In Acinetobacter baumannii (A. baumannii), a wide repertoire of resistance genes is often carried... more In Acinetobacter baumannii (A. baumannii), a wide repertoire of resistance genes is often carried within genomic resistance islands (RIs), particularly in high-risk global clones (GCs). As the first in Egypt, the current study aimed at exploring the diversity and genetic configuration of RIs in the clinical isolates of A. baumannii. For this purpose, draft genomes of 18 isolates were generated by Illumina sequencing. Disk diffusion susceptibility profiling revealed multidrug resistance (MDR) and extensive drug resistance (XDR) phenotypes in 27.7 and 72.2%, respectively. The highest susceptibility was noted for tigecycline (100.0%) followed by colistin (94.4%), for which an MIC50 of 0.25 μg/ml was recorded by the broth microdilution assay. Sequence typing (ST) showed that the majority of the isolates belonged to high-risk global clones (GC1, GC2, and GC9). A novel Oxford sequence type (ST2329) that also formed a novel clonal complex was submitted to the PubMLST database. A novel blaA...
NEURO-ONCOLOGY • JANUARY 2018 as unclassified meningiomas with probable brain invasion. For the p... more NEURO-ONCOLOGY • JANUARY 2018 as unclassified meningiomas with probable brain invasion. For the patients with probable brain invasion: 100% of patients with grade I meningioma had resection Simpson grade II; 42.8% of patients with grade II meningioma had resection Simpson grade IV and 57.1% resection grade II; 50% of patients in the unclassified group had resection Simpson grade II and 50% had resection grade IV. Following surgery, all patients were followed up with image surveillance. Recurrence was observed in two patients in the unclassified group and in one patient in the meningioma grade II group. CONCLUSIONS: Brain invasion in meningiomas is common (1 in 11 in our series): this will increase the number of meningiomas classified as grade II according to the new WHO classification, with likely implications on follow up and treatment. In a small number of cases, uncertainty on the presence of brain invasion made it difficult to accurately grade the meningioma.
Background: hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and i... more Background: hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and it is one of the major causes of death, because of its high frequency and poor prognosis. Hepatocellular carcinoma is now a common malignancy in Egypt which usually develops on top of liver cirrhosis secondary to viral infection, as hepatitis C viruses increased the risk of HCC in the Egyptian patients. Aim of the Work: was to verify the possibility of using the plasma squamous cell carcinoma antigen level as a tumor marker for hepatocellular carcinoma and to evaluate its prognostic value in management of HCC. Patients and Methods: the study included 60 subjects divided into three groups: group I was 30 patients with hepatocellular carcinomas, group II was 15 patients with liver cirrhosis and group III was 15 normal subjects serving as a control group. Results: the plasma SCCA level was significantly higher in group I patients (with HCC), than in the group II patients (cirrhosis) and control group. SCCA showed direct significant correlation with the most of laboratory data specially AST, INR, number and size of lesion. Conclusion: plasma SCCA is a sensitive and specific serum marker for the diagnosis of HCC and combination of AFP and SCCA in screening and diagnosis of HCC yielded a better sensitivity in diagnosis of HCC.
OBJECTIVE To evaluate the results of combined management of large vestibular schwannomas (VS) wit... more OBJECTIVE To evaluate the results of combined management of large vestibular schwannomas (VS) with initial subtotal resection (STR) followed by adjuvant stereotactic radiosurgery (SRS), with a particular emphasis on the timing and regimen of irradiation. METHODS Seventeen patients underwent STR of a VS followed by SRS, whereas five others were observed after STR. Early SRS (<6 months after surgery) and late SRS (>6 months after surgery) were done in 8 and 9 patients, respectively. Single- and multisession SRS treatments were administered in 10 and 7 patients, respectively. The mean follow-up durations after surgery and SRS were 40 and 28 months, respectively. RESULTS The rates of radiological and oncological tumor control after SRS were 82% and 100%, respectively. The tumor volume at the last follow-up and its relative changes after SRS did not differ significantly on the basis of the irradiation timing (early versus late) or on the basis of the irradiation regimen (single-session versus multisession). In no patient who was observed after STR of a VS was tumor regrowth noted during a mean follow-up period of 49 months. At 12 months after surgery, motor function of the ipsilateral facial nerve corresponded to House-Brackmann grades I, II, III, and IV in 16 patients (73%), 3 patients (14%), 1 patient (5%), and 2 patients (9%), respectively. Facial nerve function at the last follow-up did not differ significantly on the basis of the irradiation timing (early versus late) or on the basis of the irradiation regimen (single-session versus multisession). CONCLUSION The combination of initial STR followed by adjuvant SRS is an effective treatment strategy for patients with a large VS. Although the optimal timing and regimen of postoperative irradiation of the residual lesion should be defined further, our preliminary data suggest that either early or late SRS after surgery may provide good tumor control and optimal functional results.
Objective: Spinal infections are a significant clinical problem. Associated axial back pain has a... more Objective: Spinal infections are a significant clinical problem. Associated axial back pain has a substantial burden and disability on the patient. Management involve conservative and surgical pathways. We here present our experience with the effect of facetal radiofrequency ablation on axial back pain and quality of life for patients with primary spinal infections. Methods: A retrospective study of patients with primary pyogenic spine infection treated in the period from February 2014 through December 2017. All patients had axial back pain score of 10/10 before any intervention. All patients involved has no other associated neurological morbidity. Patients were treated with pulsed radiofrequency (PRF) of the dorsal root ganglion, conventional radiofrequency (CRF) of facet medial branch, or a combination of both techniques to improve their back pain beside conservative antibiotics management. Results: Thirty-one patients were included in this study. Mean age was 43 years. Mean follo...
A secret sharing scheme is non-perfect if some subsets of participants that cannot recover the se... more A secret sharing scheme is non-perfect if some subsets of participants that cannot recover the secret value have partial information about it. The information ratio of a secret sharing scheme is the ratio between the maximum length of the shares and the length of the secret. This work is dedicated to the search of bounds on the information ratio of non-perfect secret sharing schemes. To this end, we extend the known connections between polymatroids and perfect secret sharing schemes to the non-perfect case. In order to study non-perfect secret sharing schemes in all generality, we describe their structure through their access function, a real function that measures the amount of information that every subset of participants obtains about the secret value. We prove that there exists a secret sharing scheme for every access function. Uniform access functions, that is, the ones whose values depend only on the number of participants, generalize the threshold access structures. Our main result is to determine the optimal information ratio of the uniform access functions. Moreover, we present a construction of linear secret sharing schemes with optimal information ratio for the rational uniform access functions.
Background: Further reports are required to describe the outcome of truncal dystonia treated by b... more Background: Further reports are required to describe the outcome of truncal dystonia treated by bilateral pallidal stimulation (GPi-DBS), owing to the small number of reports and clinical variability and complexity of truncal dystonia. Retrospectively, we report our experience of treating three patients with idiopathic generalized dystonia, with predominant mobile truncal dystonia by bilateral GPi-DBS. Methods: three patients with idiopathic generalized dystonia underwent bilateral GPi-DBS. One patient had adult-onset dystonia, while two patients had childhood-onset dystonia. All patients had predominant mobile truncal dystonia of mixed abnormal postures (camptocormia and lateral tilt), while one patient had also truncal twist. Patients were assessed pre-and post-GPi-DBS using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and Dystonia Disability Scale (DDS). Results: The three patients showed marked improvement of global (94.78, 92.4 and 80.95%) and truncal BFMRS (all abnormal postures) (87.5, 93.75, and 87.5%) and DSS (95. 84 and 50%), using high amplitude monopolar settings, with a dramatic improvement of the mobile component. Improvement was persistent for 1.5, 3, and 6 years. Conclusion: Bilateral GPi-DBS improves markedly the mobile truncal dystonia and associated abnormal postures in patients with adult and childhood-onset idiopathic generalized dystonia.
Annals of Clinical Microbiology and Antimicrobials, 2019
Background Colistin resistance is mainly driven by alterations in the Gram-negative outer membran... more Background Colistin resistance is mainly driven by alterations in the Gram-negative outer membrane lipopolysaccharides and is caused, in most cases, by mutations in mgrB gene. However, the recent emergence of plasmid-encoded colistin resistance among Enterobacteriaceae strains represents a serious threat to global public health. In this paper we have investigated the rates of colistin resistance and the underlying mechanisms in 450 Klebsiella pneumoniae and Escherichia coli isolates obtained from cancer patients in Egypt. Methods Colistin susceptibility and minimum inhibitory concentrations were determined according to the European Committee on Antimicrobial Susceptibility Testing, by broth microdilution, and by E-test. The mcr-1, mcr-2 and mgrB genes were detected by PCR and then sequenced. Clonal diversity in colistin-resistant K. pneumoniae was evaluated by multilocus sequence typing. Results Forty (8.8%) colistin-resistant isolates, including 22 K. pneumoniae and 18 E. coli, wer...
The aim of this study was to investigate the mechanisms responsible for resistance to antimicrobi... more The aim of this study was to investigate the mechanisms responsible for resistance to antimicrobials in a collection of enterobacterial isolates recovered from two hospitals in Saudi Arabia. A total of six strains isolated from different patients showing high resistance to carbapenems was recovered in 2015 from two different hospitals, with four being Klebsiella pneumoniae and two Enterobacter cloacae. All isolates except one K. pneumoniae were resistant to tigecycline, but only one K. pneumoniae was resistant to colistin. All produced a carbapenemase according to the Carba NP test, and all were positive for the EDTA-disk synergy test for detection of MBL. Using PCR followed by sequencing, the four K. pneumoniae isolates produced the carbapenemase NDM-1, while the two E. cloacae isolates produced the carbapenemase VIM-1. Genotyping analysis by Multilocus Sequence Typing (MLST) showed that three out of the four K. pneumoniae isolates were clonally related. They had been recovered fro...
Stereotactic and functional neurosurgery, Jan 18, 2018
The optimum target in surgery for Parkinson's disease (PD) is still controversial, especially... more The optimum target in surgery for Parkinson's disease (PD) is still controversial, especially in patients with tremor-dominant PD. We aim to compare results in tremor-dominant patients undergoing pallidotomy vs. those undergoing simultaneous posteroventral pallidotomy (PVP) and ventral intermediate nucleus (VIM) thalamotomy. Twenty-four patients with tremor-dominant PD were included in this study. Twelve patients received unilateral PVP contralateral to the most affected side. The other 12 patients received simultaneous unilateral PVP and VIM thalamotomy contralateral to the most affected side. Assessment of results in both groups was achieved using both UPDRS "off" motor scores and UPDRS rest tremor subscores. The mean UPDRS off motor score improved in the pallidotomy group from 61.3 preoperatively to 36.8 at 12 months. In the combined group, it improved from 59.6 to 35.2 at 12 months, with no statistically significant difference between both groups. On the other hand...
The main objective of this work was to characterize carbapenemases, extended-spectrum -lactamase... more The main objective of this work was to characterize carbapenemases, extended-spectrum -lactamases (ESBLs), and plasmid-mediated quinolone resistance (PMQR) among carbapenem-insensitive Klebsiella pneumoniae and Escherichia coli clinical isolates which were isolated from three hospitals in Riyadh. Thirty-one carbapenem-insensitive isolates (21 K. pneumoniae and 10 E. coli) were recovered from March 2014 to May 2014. Susceptibility testing and phenotypic detection tests were used to characterize the classes of -lactamases. PCR assays were performed for the detection of the genes encoding ESBL (bla CTX-M , bla TEM, bla SHV , and bla OXA-1), carbapenemase (bla KPC, bla GES, bla VIM , bla IMP , bla NDM , and bla OXA-48), and PMQR (qnrA, qnrB, qnrS, aac(6)-Ib-cr, qepA, oqxA, and oqxB) genes. All carbapenem-insensitive isolates were carbapenemase producers, with 41.9% and 58.1% being class B carbapenemases class D OXA-48, respectively. While the prevalence of ESBL producers was 80.6%. The following resistance genes were detected; OXA-48-like (58.1%), NDM-type (41.9%), CTX-M-1-like (77.4%), CTX-M-9-like (9.6%), TEM-1 (74.2%), OXA-1 (54.8%), SHV-1 (4.4%), qnrS (58.1%), qnrB (3.2%), and aac(6)-Ib-cr (51.6%). The predominant carbapenemases in the isolates that had carbapenem MIC ≤ 4 g/ml and MIC ≥ 12 g/ml were bla OXA-48-type and bla NDM-type respectively. CTX-M-1-like and qnrS were the dominant ESBL and PMQR genes, respectively. This is the first report in which qnrS was described in the isolates from Saudi Arabia.
Silent corticotroph staining pituitary adenoma (SCA) represents an uncommon subset of Non-Functio... more Silent corticotroph staining pituitary adenoma (SCA) represents an uncommon subset of Non-Functioning adenomas (NFAs), hypothesized to be more locally aggressive. In this retrospective multicenter study, we investigate the safety and effectiveness of Stereotactic Radiosurgery (SRS) in patients with SCA compared with other non-SCA NFA's. Eight centers participating in the International Gamma-Knife Research Foundation (IGKRF) contributed to this study. Outcomes of
Journal of Neurological Surgery Part B: Skull Base, 2017
Aggressive pituitary corticotroph tumors causing Cushing's disease are rare, and there is limited... more Aggressive pituitary corticotroph tumors causing Cushing's disease are rare, and there is limited data about their clinical management. Here, we aimed to report our long-term experience with gamma knife radiosurgery (GKRS) as adjuvant treatment in patients with residual or recurrent pituitary corticotroph tumors. This retrospective study included 45 adult patients (M/F, 7/38; mean age, 40.2 ± 13.1 years) with residual tumor or recurrence after initially successful surgical resection. Single-session GKRS was performed in all patients. Tumors with a Ki-67 value higher than 3 % and radiologic invasion to surrounding tissues were classified as aggressive tumor group. Clinical, hormonal and radiological findings were compared between the aggressive (n = 10) and nonaggressive adenoma (n = 35) groups. Following GKRS, tumor volumes were significantly reduced in both groups. The mean time to hormonal remission in the non-aggressive group was significantly shorter than in the aggressive group (23.5 ± 6.3 vs 33.0 ± 5.0 month, respectively, p < 0.05). New-onset hypopituitarism was identified in only seven patients (15 %) after GKRS in the whole cohort. The present study introduces several essential findings about aggressive corticotroph tumors. First, aggressive behavior tends to occur more frequently in male subjects. Second, time to GKRS was significantly shorter in the aggressive group. Moreover, a tumor volume ≥2 cm 3 may be associated with clinical aggressiveness in corticotroph tumors. In conclusion, we suggest that early adjuvant GKRS is an effective treatment option in aggressive pituitary corticotroph tumors.
There is no objective and readily accessible method for the preoperative determination of atypica... more There is no objective and readily accessible method for the preoperative determination of atypical characteristics of a meningioma grade. To evaluate the feasibility of using fractal analysis as an adjunctive tool to conventional radiological techniques in visualizing histopathological features of meningiomas. A group of 27 patients diagnosed with atypical (WHO grade II) meningioma and a second group of 27 patients with benign (WHO grade I) meningioma were enrolled in the study. Preoperative brain magnetic resonance (MR) studies (T1-wieghted, post-gadolinium) were processed and analyzed to determine the average fractal dimension (FDa) and maximum fractal dimension (FDm) of the contrast-enhancing region of the tumor using box-count method. FDa and FDm as well as particular radiological features were included in the logistic regression model as possible predictors of malignancy. The cohort consisted of 34 women and 20 men, mean age of 62 ± 15 yr. Fractal analysis showed good interobse...
Background: The debate continues with a limited number of publications describing outcomes in pat... more Background: The debate continues with a limited number of publications describing outcomes in patients with vestibular schwannoma (VS) treated with planned subtotal resection (STR) plus stereotactic radiosurgery (SRS). Here we present our experience. Methods: This is a retrospective review of 22 patients with VS Koos grade III and IV who were treated with STR followed by SRS. Tumor volumes, facial nerve function, hearing preservation, and the presence of trigeminal neuropathy were noted. Spearman's rank test was used to correlate facial nerve grade with postoperative tumor residual tumor volume. Results: Tumor control was achieved in all patients with a mean follow-up of 28 months. No patient required other treatment beyond the original surgery and adjuvant SRS during this period. After a mean postoperative period of 28 months, 19/22 patients had excellent (House-Brackmann I or II) facial nerve function grading. Improved facial nerve function was positively correlated with large...
Sodium ascorbate has been suggested to modify bleaching agents' side effects especially on compos... more Sodium ascorbate has been suggested to modify bleaching agents' side effects especially on composite resin bonding to dental hard tissues. The aim of the present study was to evaluate the effect of 10% sodium ascorbate on Streptococcus mutans adherence to bleached enamel surfaces. Sixty enamel slabs from bovine incisors were used. After sterilization of the intact enamel surfaces with UV light, the specimens were randomly divided into the following treatment groups: (1) immersion in normal saline containing 2%NaN 3 ; (2) bleaching of enamel surfaces with 10% carbamide peroxide; (3) bleaching of enamel surfaces with 10% carbamide peroxide followed by 10% sodium ascorbate treatment. Adherence of S. mutans to enamel surfaces was determined bacteriologically. Data was analyzed using one-way ANOVA and post hoc Tukey tests (P < 0.05).10% sodium ascorbate after bleaching (Group 3) caused a significant increase in surface adherence of S. mutans compared to groups 1 and 2 (P < 0.001). Because of bacterial adherence subsequent to use of sodium ascorbate to bleached enamel caries risk may be increased.
In Acinetobacter baumannii (A. baumannii), a wide repertoire of resistance genes is often carried... more In Acinetobacter baumannii (A. baumannii), a wide repertoire of resistance genes is often carried within genomic resistance islands (RIs), particularly in high-risk global clones (GCs). As the first in Egypt, the current study aimed at exploring the diversity and genetic configuration of RIs in the clinical isolates of A. baumannii. For this purpose, draft genomes of 18 isolates were generated by Illumina sequencing. Disk diffusion susceptibility profiling revealed multidrug resistance (MDR) and extensive drug resistance (XDR) phenotypes in 27.7 and 72.2%, respectively. The highest susceptibility was noted for tigecycline (100.0%) followed by colistin (94.4%), for which an MIC50 of 0.25 μg/ml was recorded by the broth microdilution assay. Sequence typing (ST) showed that the majority of the isolates belonged to high-risk global clones (GC1, GC2, and GC9). A novel Oxford sequence type (ST2329) that also formed a novel clonal complex was submitted to the PubMLST database. A novel blaA...
NEURO-ONCOLOGY • JANUARY 2018 as unclassified meningiomas with probable brain invasion. For the p... more NEURO-ONCOLOGY • JANUARY 2018 as unclassified meningiomas with probable brain invasion. For the patients with probable brain invasion: 100% of patients with grade I meningioma had resection Simpson grade II; 42.8% of patients with grade II meningioma had resection Simpson grade IV and 57.1% resection grade II; 50% of patients in the unclassified group had resection Simpson grade II and 50% had resection grade IV. Following surgery, all patients were followed up with image surveillance. Recurrence was observed in two patients in the unclassified group and in one patient in the meningioma grade II group. CONCLUSIONS: Brain invasion in meningiomas is common (1 in 11 in our series): this will increase the number of meningiomas classified as grade II according to the new WHO classification, with likely implications on follow up and treatment. In a small number of cases, uncertainty on the presence of brain invasion made it difficult to accurately grade the meningioma.
Background: hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and i... more Background: hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and it is one of the major causes of death, because of its high frequency and poor prognosis. Hepatocellular carcinoma is now a common malignancy in Egypt which usually develops on top of liver cirrhosis secondary to viral infection, as hepatitis C viruses increased the risk of HCC in the Egyptian patients. Aim of the Work: was to verify the possibility of using the plasma squamous cell carcinoma antigen level as a tumor marker for hepatocellular carcinoma and to evaluate its prognostic value in management of HCC. Patients and Methods: the study included 60 subjects divided into three groups: group I was 30 patients with hepatocellular carcinomas, group II was 15 patients with liver cirrhosis and group III was 15 normal subjects serving as a control group. Results: the plasma SCCA level was significantly higher in group I patients (with HCC), than in the group II patients (cirrhosis) and control group. SCCA showed direct significant correlation with the most of laboratory data specially AST, INR, number and size of lesion. Conclusion: plasma SCCA is a sensitive and specific serum marker for the diagnosis of HCC and combination of AFP and SCCA in screening and diagnosis of HCC yielded a better sensitivity in diagnosis of HCC.
OBJECTIVE To evaluate the results of combined management of large vestibular schwannomas (VS) wit... more OBJECTIVE To evaluate the results of combined management of large vestibular schwannomas (VS) with initial subtotal resection (STR) followed by adjuvant stereotactic radiosurgery (SRS), with a particular emphasis on the timing and regimen of irradiation. METHODS Seventeen patients underwent STR of a VS followed by SRS, whereas five others were observed after STR. Early SRS (<6 months after surgery) and late SRS (>6 months after surgery) were done in 8 and 9 patients, respectively. Single- and multisession SRS treatments were administered in 10 and 7 patients, respectively. The mean follow-up durations after surgery and SRS were 40 and 28 months, respectively. RESULTS The rates of radiological and oncological tumor control after SRS were 82% and 100%, respectively. The tumor volume at the last follow-up and its relative changes after SRS did not differ significantly on the basis of the irradiation timing (early versus late) or on the basis of the irradiation regimen (single-session versus multisession). In no patient who was observed after STR of a VS was tumor regrowth noted during a mean follow-up period of 49 months. At 12 months after surgery, motor function of the ipsilateral facial nerve corresponded to House-Brackmann grades I, II, III, and IV in 16 patients (73%), 3 patients (14%), 1 patient (5%), and 2 patients (9%), respectively. Facial nerve function at the last follow-up did not differ significantly on the basis of the irradiation timing (early versus late) or on the basis of the irradiation regimen (single-session versus multisession). CONCLUSION The combination of initial STR followed by adjuvant SRS is an effective treatment strategy for patients with a large VS. Although the optimal timing and regimen of postoperative irradiation of the residual lesion should be defined further, our preliminary data suggest that either early or late SRS after surgery may provide good tumor control and optimal functional results.
Objective: Spinal infections are a significant clinical problem. Associated axial back pain has a... more Objective: Spinal infections are a significant clinical problem. Associated axial back pain has a substantial burden and disability on the patient. Management involve conservative and surgical pathways. We here present our experience with the effect of facetal radiofrequency ablation on axial back pain and quality of life for patients with primary spinal infections. Methods: A retrospective study of patients with primary pyogenic spine infection treated in the period from February 2014 through December 2017. All patients had axial back pain score of 10/10 before any intervention. All patients involved has no other associated neurological morbidity. Patients were treated with pulsed radiofrequency (PRF) of the dorsal root ganglion, conventional radiofrequency (CRF) of facet medial branch, or a combination of both techniques to improve their back pain beside conservative antibiotics management. Results: Thirty-one patients were included in this study. Mean age was 43 years. Mean follo...
A secret sharing scheme is non-perfect if some subsets of participants that cannot recover the se... more A secret sharing scheme is non-perfect if some subsets of participants that cannot recover the secret value have partial information about it. The information ratio of a secret sharing scheme is the ratio between the maximum length of the shares and the length of the secret. This work is dedicated to the search of bounds on the information ratio of non-perfect secret sharing schemes. To this end, we extend the known connections between polymatroids and perfect secret sharing schemes to the non-perfect case. In order to study non-perfect secret sharing schemes in all generality, we describe their structure through their access function, a real function that measures the amount of information that every subset of participants obtains about the secret value. We prove that there exists a secret sharing scheme for every access function. Uniform access functions, that is, the ones whose values depend only on the number of participants, generalize the threshold access structures. Our main result is to determine the optimal information ratio of the uniform access functions. Moreover, we present a construction of linear secret sharing schemes with optimal information ratio for the rational uniform access functions.
Background: Further reports are required to describe the outcome of truncal dystonia treated by b... more Background: Further reports are required to describe the outcome of truncal dystonia treated by bilateral pallidal stimulation (GPi-DBS), owing to the small number of reports and clinical variability and complexity of truncal dystonia. Retrospectively, we report our experience of treating three patients with idiopathic generalized dystonia, with predominant mobile truncal dystonia by bilateral GPi-DBS. Methods: three patients with idiopathic generalized dystonia underwent bilateral GPi-DBS. One patient had adult-onset dystonia, while two patients had childhood-onset dystonia. All patients had predominant mobile truncal dystonia of mixed abnormal postures (camptocormia and lateral tilt), while one patient had also truncal twist. Patients were assessed pre-and post-GPi-DBS using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and Dystonia Disability Scale (DDS). Results: The three patients showed marked improvement of global (94.78, 92.4 and 80.95%) and truncal BFMRS (all abnormal postures) (87.5, 93.75, and 87.5%) and DSS (95. 84 and 50%), using high amplitude monopolar settings, with a dramatic improvement of the mobile component. Improvement was persistent for 1.5, 3, and 6 years. Conclusion: Bilateral GPi-DBS improves markedly the mobile truncal dystonia and associated abnormal postures in patients with adult and childhood-onset idiopathic generalized dystonia.
Annals of Clinical Microbiology and Antimicrobials, 2019
Background Colistin resistance is mainly driven by alterations in the Gram-negative outer membran... more Background Colistin resistance is mainly driven by alterations in the Gram-negative outer membrane lipopolysaccharides and is caused, in most cases, by mutations in mgrB gene. However, the recent emergence of plasmid-encoded colistin resistance among Enterobacteriaceae strains represents a serious threat to global public health. In this paper we have investigated the rates of colistin resistance and the underlying mechanisms in 450 Klebsiella pneumoniae and Escherichia coli isolates obtained from cancer patients in Egypt. Methods Colistin susceptibility and minimum inhibitory concentrations were determined according to the European Committee on Antimicrobial Susceptibility Testing, by broth microdilution, and by E-test. The mcr-1, mcr-2 and mgrB genes were detected by PCR and then sequenced. Clonal diversity in colistin-resistant K. pneumoniae was evaluated by multilocus sequence typing. Results Forty (8.8%) colistin-resistant isolates, including 22 K. pneumoniae and 18 E. coli, wer...
The aim of this study was to investigate the mechanisms responsible for resistance to antimicrobi... more The aim of this study was to investigate the mechanisms responsible for resistance to antimicrobials in a collection of enterobacterial isolates recovered from two hospitals in Saudi Arabia. A total of six strains isolated from different patients showing high resistance to carbapenems was recovered in 2015 from two different hospitals, with four being Klebsiella pneumoniae and two Enterobacter cloacae. All isolates except one K. pneumoniae were resistant to tigecycline, but only one K. pneumoniae was resistant to colistin. All produced a carbapenemase according to the Carba NP test, and all were positive for the EDTA-disk synergy test for detection of MBL. Using PCR followed by sequencing, the four K. pneumoniae isolates produced the carbapenemase NDM-1, while the two E. cloacae isolates produced the carbapenemase VIM-1. Genotyping analysis by Multilocus Sequence Typing (MLST) showed that three out of the four K. pneumoniae isolates were clonally related. They had been recovered fro...
Stereotactic and functional neurosurgery, Jan 18, 2018
The optimum target in surgery for Parkinson's disease (PD) is still controversial, especially... more The optimum target in surgery for Parkinson's disease (PD) is still controversial, especially in patients with tremor-dominant PD. We aim to compare results in tremor-dominant patients undergoing pallidotomy vs. those undergoing simultaneous posteroventral pallidotomy (PVP) and ventral intermediate nucleus (VIM) thalamotomy. Twenty-four patients with tremor-dominant PD were included in this study. Twelve patients received unilateral PVP contralateral to the most affected side. The other 12 patients received simultaneous unilateral PVP and VIM thalamotomy contralateral to the most affected side. Assessment of results in both groups was achieved using both UPDRS "off" motor scores and UPDRS rest tremor subscores. The mean UPDRS off motor score improved in the pallidotomy group from 61.3 preoperatively to 36.8 at 12 months. In the combined group, it improved from 59.6 to 35.2 at 12 months, with no statistically significant difference between both groups. On the other hand...
The main objective of this work was to characterize carbapenemases, extended-spectrum -lactamase... more The main objective of this work was to characterize carbapenemases, extended-spectrum -lactamases (ESBLs), and plasmid-mediated quinolone resistance (PMQR) among carbapenem-insensitive Klebsiella pneumoniae and Escherichia coli clinical isolates which were isolated from three hospitals in Riyadh. Thirty-one carbapenem-insensitive isolates (21 K. pneumoniae and 10 E. coli) were recovered from March 2014 to May 2014. Susceptibility testing and phenotypic detection tests were used to characterize the classes of -lactamases. PCR assays were performed for the detection of the genes encoding ESBL (bla CTX-M , bla TEM, bla SHV , and bla OXA-1), carbapenemase (bla KPC, bla GES, bla VIM , bla IMP , bla NDM , and bla OXA-48), and PMQR (qnrA, qnrB, qnrS, aac(6)-Ib-cr, qepA, oqxA, and oqxB) genes. All carbapenem-insensitive isolates were carbapenemase producers, with 41.9% and 58.1% being class B carbapenemases class D OXA-48, respectively. While the prevalence of ESBL producers was 80.6%. The following resistance genes were detected; OXA-48-like (58.1%), NDM-type (41.9%), CTX-M-1-like (77.4%), CTX-M-9-like (9.6%), TEM-1 (74.2%), OXA-1 (54.8%), SHV-1 (4.4%), qnrS (58.1%), qnrB (3.2%), and aac(6)-Ib-cr (51.6%). The predominant carbapenemases in the isolates that had carbapenem MIC ≤ 4 g/ml and MIC ≥ 12 g/ml were bla OXA-48-type and bla NDM-type respectively. CTX-M-1-like and qnrS were the dominant ESBL and PMQR genes, respectively. This is the first report in which qnrS was described in the isolates from Saudi Arabia.
Silent corticotroph staining pituitary adenoma (SCA) represents an uncommon subset of Non-Functio... more Silent corticotroph staining pituitary adenoma (SCA) represents an uncommon subset of Non-Functioning adenomas (NFAs), hypothesized to be more locally aggressive. In this retrospective multicenter study, we investigate the safety and effectiveness of Stereotactic Radiosurgery (SRS) in patients with SCA compared with other non-SCA NFA's. Eight centers participating in the International Gamma-Knife Research Foundation (IGKRF) contributed to this study. Outcomes of
Journal of Neurological Surgery Part B: Skull Base, 2017
Aggressive pituitary corticotroph tumors causing Cushing's disease are rare, and there is limited... more Aggressive pituitary corticotroph tumors causing Cushing's disease are rare, and there is limited data about their clinical management. Here, we aimed to report our long-term experience with gamma knife radiosurgery (GKRS) as adjuvant treatment in patients with residual or recurrent pituitary corticotroph tumors. This retrospective study included 45 adult patients (M/F, 7/38; mean age, 40.2 ± 13.1 years) with residual tumor or recurrence after initially successful surgical resection. Single-session GKRS was performed in all patients. Tumors with a Ki-67 value higher than 3 % and radiologic invasion to surrounding tissues were classified as aggressive tumor group. Clinical, hormonal and radiological findings were compared between the aggressive (n = 10) and nonaggressive adenoma (n = 35) groups. Following GKRS, tumor volumes were significantly reduced in both groups. The mean time to hormonal remission in the non-aggressive group was significantly shorter than in the aggressive group (23.5 ± 6.3 vs 33.0 ± 5.0 month, respectively, p < 0.05). New-onset hypopituitarism was identified in only seven patients (15 %) after GKRS in the whole cohort. The present study introduces several essential findings about aggressive corticotroph tumors. First, aggressive behavior tends to occur more frequently in male subjects. Second, time to GKRS was significantly shorter in the aggressive group. Moreover, a tumor volume ≥2 cm 3 may be associated with clinical aggressiveness in corticotroph tumors. In conclusion, we suggest that early adjuvant GKRS is an effective treatment option in aggressive pituitary corticotroph tumors.
There is no objective and readily accessible method for the preoperative determination of atypica... more There is no objective and readily accessible method for the preoperative determination of atypical characteristics of a meningioma grade. To evaluate the feasibility of using fractal analysis as an adjunctive tool to conventional radiological techniques in visualizing histopathological features of meningiomas. A group of 27 patients diagnosed with atypical (WHO grade II) meningioma and a second group of 27 patients with benign (WHO grade I) meningioma were enrolled in the study. Preoperative brain magnetic resonance (MR) studies (T1-wieghted, post-gadolinium) were processed and analyzed to determine the average fractal dimension (FDa) and maximum fractal dimension (FDm) of the contrast-enhancing region of the tumor using box-count method. FDa and FDm as well as particular radiological features were included in the logistic regression model as possible predictors of malignancy. The cohort consisted of 34 women and 20 men, mean age of 62 ± 15 yr. Fractal analysis showed good interobse...
Background: The debate continues with a limited number of publications describing outcomes in pat... more Background: The debate continues with a limited number of publications describing outcomes in patients with vestibular schwannoma (VS) treated with planned subtotal resection (STR) plus stereotactic radiosurgery (SRS). Here we present our experience. Methods: This is a retrospective review of 22 patients with VS Koos grade III and IV who were treated with STR followed by SRS. Tumor volumes, facial nerve function, hearing preservation, and the presence of trigeminal neuropathy were noted. Spearman's rank test was used to correlate facial nerve grade with postoperative tumor residual tumor volume. Results: Tumor control was achieved in all patients with a mean follow-up of 28 months. No patient required other treatment beyond the original surgery and adjuvant SRS during this period. After a mean postoperative period of 28 months, 19/22 patients had excellent (House-Brackmann I or II) facial nerve function grading. Improved facial nerve function was positively correlated with large...
Sodium ascorbate has been suggested to modify bleaching agents' side effects especially on compos... more Sodium ascorbate has been suggested to modify bleaching agents' side effects especially on composite resin bonding to dental hard tissues. The aim of the present study was to evaluate the effect of 10% sodium ascorbate on Streptococcus mutans adherence to bleached enamel surfaces. Sixty enamel slabs from bovine incisors were used. After sterilization of the intact enamel surfaces with UV light, the specimens were randomly divided into the following treatment groups: (1) immersion in normal saline containing 2%NaN 3 ; (2) bleaching of enamel surfaces with 10% carbamide peroxide; (3) bleaching of enamel surfaces with 10% carbamide peroxide followed by 10% sodium ascorbate treatment. Adherence of S. mutans to enamel surfaces was determined bacteriologically. Data was analyzed using one-way ANOVA and post hoc Tukey tests (P < 0.05).10% sodium ascorbate after bleaching (Group 3) caused a significant increase in surface adherence of S. mutans compared to groups 1 and 2 (P < 0.001). Because of bacterial adherence subsequent to use of sodium ascorbate to bleached enamel caries risk may be increased.
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Papers by Hesham Radwan