Immunoassays are laboratory technologies used for cost-effective and sensitive assessment of many... more Immunoassays are laboratory technologies used for cost-effective and sensitive assessment of many different analytes. These analytes account for about 25% of the tests done at large regional laboratories and include tests ranging from those for specific drugs like Dilantin and Digoxin; proteins like PSA, Troponin, and Ferritin; vitamins like Vitamin B12 and Folate; and hormones like TSH, free T4, Estradiol, Progesterone, and Testosterone, and many others. Recognition of the analyte by the assays occurs through complex interaction of antibodies within the assay reagent with certain parts of the analyte molecule.
BACKGROUND Immunoassays provide a rapid tool for the screening of drugs-of-abuse (DOA). However, ... more BACKGROUND Immunoassays provide a rapid tool for the screening of drugs-of-abuse (DOA). However, results are presumptive and confirmatory testing is warranted. To reduce associated cost and delay, laboratories should employ assays with high positive and negative predictive values (PPVs and NPVs). Here, we compared the results of urine drug screens on cobas 6000 (cobas) and ARCHITECTi2000 (ARCHITECT) platforms for six drugs against LC-MS/MS to assess the analytical performance of these assays. METHODS Eighty nine residual urine specimens, which tested positive for amphetamine, THC-COOH, benzoylecgonine, EDDP, opiates and/or oxycodone during routine drug testing, were stored frozen until later confirmation by LC-MS/MS. Immunoassays were performed on cobas and ARCHITECT using a split sample. A third aliquot from these samples was tested by LC-MS/MS to assess the percentage of false positive, false negative, true positive and true negative results and calculate the PPVs and NPVs for each immunoassay. RESULTS The PPVs of THC-COOH and EDDP assays were 100% on both platforms. Suboptimal PPVs were achieved for oxycodone (cobas, 57.1% vs ARCHITECT, 66.7%), amphetamine (77.8 vs. 100%), opiates (80.0 vs. 84.6%) and benzoylecgonine (88.9 vs. 84.2%) assays. The NPV was 100% for cobas and ARCHITECT oxycodone assays. Lower NPVs were achieved for THC-COOH (cobas, 28.6% vs ARCHITECT, 25.0%), EDDP (72.7% for both assays), benzoylecgonine (74.4% vs 73.8%), amphetamine (83.3% vs 82.8%) and opiates (100% vs 85.3%). CONCLUSION Overall, cobas and ARCHITECT urine drug screens have comparable analytical performance. Confirmatory testing is warranted for positive test results especially for oxycodone, amphetamine, opiates and cocaine. Negative drug screen results must be interpreted with caution especially for THC-COOH, EDDP, benzoylecgonine, amphetamine and opiates.
ackground: The ketogenic diet is used to treat epilepsy refractory to anticonvulsant medication. ... more ackground: The ketogenic diet is used to treat epilepsy refractory to anticonvulsant medication. Individuals with epilepsy often have ehavioral problems and deficits in attention and cognitive functioning. The ketogenic diet has been found to effect improvements in hese domains. It has also been suggested that the ketogenic diet may act as a mood stabilizer. ethods: The present research used the Porsolt test, an animal model of depression, to determine whether the ketogenic diet has ntidepressant properties. Porsolt test scores of rats on the ketogenic diet were compared with those of rats on a control diet. esults: The rats on the ketogenic diet spent less time immobile, suggesting that rats on the ketogenic diet, like rats treated with ntidepressants, are less likely to exhibit “behavioral despair.” onclusions: It is concluded that the ketogenic diet may have antidepressant properties.
BACKGROUND The mechanism of a high-fat, low-carbohydrate ketogenic diet (KD) in alleviating drug-... more BACKGROUND The mechanism of a high-fat, low-carbohydrate ketogenic diet (KD) in alleviating drug-resistant epilepsy is unknown but may be related to systemic ketosis induced under this treatment. The need for frequent measurement of systemic ketosis, which is essential for improving maintenance of the KD in patients and for studying mechanism of the KD action, has prompted us to validate the breath acetone test as a fast, reliable, and noninvasive tool for ketosis assessment. METHODS A rat model of the KD that allowed frequent blood sampling was used to investigate how well breath acetone reflects plasma beta-hydroxybutyrate (beta-HBA), the most commonly measured ketone body. Rat pups (20 days of age) were introduced to and maintained on a KD or control diet for 33 days. During this period, breath acetone, plasma beta-HBA, blood glucose, and body weight were measured approximately every 4th day. A correlational analysis of breath acetone and plasma beta-HBA was conducted. RESULTS Br...
Journal of Liquid Chromatography & Related Technologies, 2019
Objectives: The objective of this study was the investigation of age-and sex-associations in a se... more Objectives: The objective of this study was the investigation of age-and sex-associations in a set of blood plasma metabolites in healthy male and female subjects. Methods: A comparison study design with male and female subjects of various ages was used. Metabolic profiling was performed using electrospray ionization tandem mass spectrometry that yielded 186 metabolite concentrations for each study participant. The key age-related metabolites were identified using an integrative analysis of absolute concentrations, metabolite ratios and the differential correlation of pairwise metabolite concentrations. All of the age-associated metabolites were adjusted prior to the analysis to account for differences in Body Mass Index (BMI). Results: A total of 236 plasma samples from 140 female and 96 male subjects aged 20 to 82 yearsold were collected and analyzed in the study. 13 and 14 age-associated metabolites (jrj > 0.33 and p < 6.6Â10 À5), 438 and 337 age-associated metabolite ratios (jrj > 0.37 and p < 3.5Â10 À6), and 5 and 10 core metabolites were discovered in the female and male groups, respectively. 80% of the metabolites displaying associations with age belonged to sphingolipids and phosphatidylcholines, and the two sexes shared less than 50% of the age-associated metabolites. Conclusion: The study found that changes in metabolite concentrations, metabolite ratios and differential correlations were age and sex-specific.
Multiple factors can help predict knee osteoarthritis (OA) patients from healthy individuals, inc... more Multiple factors can help predict knee osteoarthritis (OA) patients from healthy individuals, including age, sex, and BMI, and possibly metabolite levels. Using plasma from individuals with primary OA undergoing total knee replacement and healthy volunteers, we measured lysophosphatidylcholine (lysoPC) and phosphatidylcholine (PC) analogues by metabolomics. Populations were stratified on demographic factors and lysoPC and PC analogue signatures were determined by univariate receiver-operator curve (AUC) analysis. Using signatures, multivariate classification modeling was performed using various algorithms to select the most consistent method as measured by AUC differences between resampled training and test sets. Lists of metabolites indicative of OA [AUC > 0.5] were identified for each stratum. The signature from males age > 50 years old encompassed the majority of identified metabolites, suggesting lysoPCs and PCs are dominant indicators of OA in older males. Principal component regression with logistic regression was the most consistent multivariate classification algorithm tested. Using this algorithm, classification of older males had fair power to classify OA patients from healthy individuals. Thus, individual levels of lysoPC and PC analogues may be indicative of individuals with OA in older populations, particularly males. Our metabolite signature modeling method is likely to increase classification power in validation cohorts.
Menopause is an endocrine-related transition that induces a number of physiological and potential... more Menopause is an endocrine-related transition that induces a number of physiological and potentially pathological changes in middle-aged and elderly women. The intention of this research was to investigate the influence of menopause on the intricate relationships between major biochemical metabolites. The study involved metabolic profiling of 186 metabolic markers measured in blood plasma collected from 120 healthy female participants. We developed a method of network analysis using differential correlation that enabled us to detect and characterize differences in metabolites and changes in interrelationships in preand post-menopausal women. A topological analysis was performed on the differential network that uncovered metabolite differences in pre-and post-menopausal women. In this analysis, our method identified two key metabolites, sphingomyelins and phosphatidylcholines, which may be useful in directing further studies into menopause-specific differences in the metabolome, and how these differences may underlie the body's response to stress and disease following the transition from pre-to post-menopausal status for women.
Purpose: Anterior cruciate ligament tears (ACLT) are associated with a large knee effusion which ... more Purpose: Anterior cruciate ligament tears (ACLT) are associated with a large knee effusion which likely contains an early inflammatory response that may represent an early attempt at healing but ultimately leads to cartilage degeneration. Little is known about the composition of the synovial fluid (SF) in effusions after ACLT and whether it changes with time from injury. The purpose of this study is to determine the pattern of SF biomarkers after ACLT to test the hypotheses that it (a) differs from the pattern of SF biomarkers in knees with OA, (b) exhibits a response dependent on time-frominjury, and (c) varies based on the presence or absence of concomitant meniscus injury. Methods: SF was aspirated in the clinic from patients with ACLTs without any evidence for OA (N ¼ 13) and from patients with moderate to severe OA (N ¼ 16). Assessment of numerous pro-and anti-inflammatory cytokines, growth factors and chemokines was performed using multiplexed panel of 45 proteins. Nitric oxide (NO) was measured by Griess' reagent system.
To determine whether pre-existing nephropathy impacts urinary KIM-1 levels, urinary KIM-1 were me... more To determine whether pre-existing nephropathy impacts urinary KIM-1 levels, urinary KIM-1 were measured in patients with normal kidney filtration function but either with or without proteinuria. The reference intervals of urinary KIM-1 in adults with normal kidney filtration function but without urine proteinuria were established. Design and methods: 188 urine samples were obtained from adults with normal kidney filtration. 83 of the 188 showed negative urine protein, erythrocytes and leucocytes were used as normal controls. The remaining 105 samples showed at least one abnormal result suggesting possible preexisting nephropathy. Urinary KIM-1 concentrations were measured using an enzyme-linked immunosorbent assay. Urinary KIM-1 was normalized with urine creatinine concentration. The reference interval for urinary KIM-1 was determined by non-parametric methodology on 147 individuals. Results: The results showed significantly increased urinary KIM-1 concentration in protein positive (protein þ, erythrocyte þ/À, leucocyteþ/-) samples compared to controls (protein-, erythrocyte-, leucocyte-). Urinary KIM-1 concentrations were significantly higher when proteinuria was at trace concentration (0.25 g/L) and correlated with the severity of proteinuria. The creatinine normalized urinary KIM-1 was significantly higher when urine protein was 1 þ to 3þ (0.75-5 g/L). The reference interval for urinary KIM-1 was 0.00 (90%CI: 0-0) to 4.19 (90%CI: 3.11-5.62) μg/L, and for creatinine normalized urinary KIM-1 0.00 (90%CI: 0-0) to 0.58 (90%CI: 0.44-0.74) μg/mmol. Conclusions: Baseline urinary KIM-1 concentrations were increased when there was detectable urine protein and correlated with its severity. The urinary KIM-1 concentrations should be interpreted with consideration of urine protein levels in individual patients.
Background: Ketogenic diets are used therapeutically to treat intractable seizures. Clinically, i... more Background: Ketogenic diets are used therapeutically to treat intractable seizures. Clinically, it appears that the maintenance of ketosis is crucial to the efficacy of the diet in ameliorating seizures. To understand how ketosis and seizure protection are related, a reliable, noninvasive measure of ketosis that can be performed frequently with minimal discomfort is needed. Objective: The objective was to determine which index, breath acetone or urinary acetoacetate, is more strongly related to the plasma ketones acetoacetate and -hydroxybutyrate. Design: After fasting overnight for 12 h, 12 healthy adults consumed 4 ketogenic meals over 12 h. Blood, breath, and urine samples were collected hourly. Blood was analyzed for plasma acetoacetate and -hydroxybutyrate, breath for acetone, and urine for acetoacetate. Results: By the end of the 12-h dietary treatment, plasma acetoacetate, plasma -hydroxybutyrate, and breath acetone had increased 3.5-fold, whereas urinary acetoacetate increased 13-fold when measured enzymatically and 25-fold when measured with urinary ketone dipsticks. Plasma acetoacetate was best predicted by breath acetone (R 2 = 0.70, P < 0.0001). Plasma -hydroxybutyrate was equally predicted by breath acetone and urinary acetoacetate (R 2 = 0.54, P = 0.0040). Conclusions: Breath acetone is as good a predictor of ketosis as is urinary acetoacetate. Breath acetone analysis is noninvasive and can be performed frequently with minimal discomfort to patients. As an indicator of ketosis in epilepsy patients consuming a ketogenic diet, breath acetone may be useful for understanding the mechanism of the diet, elucidating the importance of ketosis in seizure protection, and ultimately, enhancing the efficacy of the diet by improving patient monitoring.
Females and males are known to have different abilities to cope with stress and disease. This stu... more Females and males are known to have different abilities to cope with stress and disease. This study was designed to investigate the effect of sex on properties of a complex interlinked network constructed of central biochemical metabolites. The study involved the blood collection and analysis of a large set of blood metabolic markers from a total of 236 healthy participants, which included 140 females and 96 males. Metabolic profiling yielded concentrations of 168 metabolites for each subject. A differential correlation network analysis approach was developed for this study that allowed detection and characterization of interconnection differences in metabolites in males and females. Through topological analysis of the differential network that depicted metabolite differences in the sexes, we identified metabolites with high centralities in this network. These key metabolites were identified as 10 phosphatidylcholines (
analysis (IBM SPSS Statistics, 19.01) was performed using repeated measures ANOVA (p<0.05). Resul... more analysis (IBM SPSS Statistics, 19.01) was performed using repeated measures ANOVA (p<0.05). Results: BR lead to a reduction in sCOMP after 24h for all interventions and the control condition (Fig.1). sCOMP recovered to baseline after the end of BR for all conditions (
To test whether type 2 diabetic patients have an elevated level of advanced glycation end-product... more To test whether type 2 diabetic patients have an elevated level of advanced glycation end-products (AGEs) and responsible for altered phosphatidylcholine metabolism, which we recently found to be associated with osteoarthritis (OA) and diabetes mellitus (DM), synovial fluid (SF) and plasma samples were collected from OA patients with and without DM. Hyperglycemia-related AGEs including methylglyoxal (MG), free methylglyoxal-derived hydroimidazolone (MG-H1), and protein bound N-(Carboxymethyl)lysine (CML) and N-(Carboxyethyl)lysine (CEL) levels were measured in both SF and plasma samples using liquid chromatography coupled tandem mass spectrometry methodology. The correlation between these AGEs and phosphatidylcholine acyl-alkyl C34:3 (PC ae C34:3) and C36:3 (PC ae C36:3) were examined. Eighty four patients with knee OA, including 46 with DM and 38 without DM, were included in the study. There was no significant difference in plasma levels of MG, MG-H1, CML, and CEL between OA patients with and without DM. However, the levels of MG and MG-H1, but not CML and CEL in SF were significantly higher in OA patients with DM than in those without (all p 0.04). This association strengthened after adjustment for age, body mass index (BMI), sex and hexose level (p<0.02). Moreover, the levels of MG-H1 in SF was negatively and significantly correlated with PC ae C34:3 (ρ =-0.34; p = 0.02) and PC ae C36:3 (ρ =-0.39; P = 0.03) after the adjustment of age, BMI, sex and hexose level. Our data indicated that the production of non-protein bound AGEs was increased within the OA-affected joint of DM patients. This is associated with changes in phosphatidylcholine metabolism and might be responsible for the observed epidemiological association between OA and DM.
To identify novel biomarker(s) for predicting advanced knee OA. Study participants were derived f... more To identify novel biomarker(s) for predicting advanced knee OA. Study participants were derived from the Newfoundland Osteoarthritis Study and the Tasmania Older Adult Cohort Study. All knee OA cases were patients who underwent total knee replacement (TKR) due to primary OA. Metabolic profiling was performed on fasting plasma. Four thousand and eighteen plasma metabolite ratios that were highly correlated with that in SF in our previous study were generated as surrogates for joint metabolism. The discovery cohort included 64 TKR cases and 45 controls and the replication cohorts included a cross-sectional cohort of 72 TKR cases and 76 controls and a longitudinal cohort of 158 subjects, of whom 36 underwent TKR during the 10-year follow-up period. We confirmed the previously reported association of the branched chain amino acids to histidine ratio with advanced knee OA (P = 9.3 × 10(-7)) and identified a novel metabolic marker-the lysophosphatidylcholines (lysoPCs) to phosphatidylchol...
In the early 1900s, medical practitioners recognized fasting as an effective method for controlli... more In the early 1900s, medical practitioners recognized fasting as an effective method for controlling seizures (1,2). The mechanism by which fasting suppressed seizures was initially explained as an alleviation of “intestinal intoxication,” which in turn was thought to be the cause of epilepsy (1).
Immunoassays are laboratory technologies used for cost-effective and sensitive assessment of many... more Immunoassays are laboratory technologies used for cost-effective and sensitive assessment of many different analytes. These analytes account for about 25% of the tests done at large regional laboratories and include tests ranging from those for specific drugs like Dilantin and Digoxin; proteins like PSA, Troponin, and Ferritin; vitamins like Vitamin B12 and Folate; and hormones like TSH, free T4, Estradiol, Progesterone, and Testosterone, and many others. Recognition of the analyte by the assays occurs through complex interaction of antibodies within the assay reagent with certain parts of the analyte molecule.
BACKGROUND Immunoassays provide a rapid tool for the screening of drugs-of-abuse (DOA). However, ... more BACKGROUND Immunoassays provide a rapid tool for the screening of drugs-of-abuse (DOA). However, results are presumptive and confirmatory testing is warranted. To reduce associated cost and delay, laboratories should employ assays with high positive and negative predictive values (PPVs and NPVs). Here, we compared the results of urine drug screens on cobas 6000 (cobas) and ARCHITECTi2000 (ARCHITECT) platforms for six drugs against LC-MS/MS to assess the analytical performance of these assays. METHODS Eighty nine residual urine specimens, which tested positive for amphetamine, THC-COOH, benzoylecgonine, EDDP, opiates and/or oxycodone during routine drug testing, were stored frozen until later confirmation by LC-MS/MS. Immunoassays were performed on cobas and ARCHITECT using a split sample. A third aliquot from these samples was tested by LC-MS/MS to assess the percentage of false positive, false negative, true positive and true negative results and calculate the PPVs and NPVs for each immunoassay. RESULTS The PPVs of THC-COOH and EDDP assays were 100% on both platforms. Suboptimal PPVs were achieved for oxycodone (cobas, 57.1% vs ARCHITECT, 66.7%), amphetamine (77.8 vs. 100%), opiates (80.0 vs. 84.6%) and benzoylecgonine (88.9 vs. 84.2%) assays. The NPV was 100% for cobas and ARCHITECT oxycodone assays. Lower NPVs were achieved for THC-COOH (cobas, 28.6% vs ARCHITECT, 25.0%), EDDP (72.7% for both assays), benzoylecgonine (74.4% vs 73.8%), amphetamine (83.3% vs 82.8%) and opiates (100% vs 85.3%). CONCLUSION Overall, cobas and ARCHITECT urine drug screens have comparable analytical performance. Confirmatory testing is warranted for positive test results especially for oxycodone, amphetamine, opiates and cocaine. Negative drug screen results must be interpreted with caution especially for THC-COOH, EDDP, benzoylecgonine, amphetamine and opiates.
ackground: The ketogenic diet is used to treat epilepsy refractory to anticonvulsant medication. ... more ackground: The ketogenic diet is used to treat epilepsy refractory to anticonvulsant medication. Individuals with epilepsy often have ehavioral problems and deficits in attention and cognitive functioning. The ketogenic diet has been found to effect improvements in hese domains. It has also been suggested that the ketogenic diet may act as a mood stabilizer. ethods: The present research used the Porsolt test, an animal model of depression, to determine whether the ketogenic diet has ntidepressant properties. Porsolt test scores of rats on the ketogenic diet were compared with those of rats on a control diet. esults: The rats on the ketogenic diet spent less time immobile, suggesting that rats on the ketogenic diet, like rats treated with ntidepressants, are less likely to exhibit “behavioral despair.” onclusions: It is concluded that the ketogenic diet may have antidepressant properties.
BACKGROUND The mechanism of a high-fat, low-carbohydrate ketogenic diet (KD) in alleviating drug-... more BACKGROUND The mechanism of a high-fat, low-carbohydrate ketogenic diet (KD) in alleviating drug-resistant epilepsy is unknown but may be related to systemic ketosis induced under this treatment. The need for frequent measurement of systemic ketosis, which is essential for improving maintenance of the KD in patients and for studying mechanism of the KD action, has prompted us to validate the breath acetone test as a fast, reliable, and noninvasive tool for ketosis assessment. METHODS A rat model of the KD that allowed frequent blood sampling was used to investigate how well breath acetone reflects plasma beta-hydroxybutyrate (beta-HBA), the most commonly measured ketone body. Rat pups (20 days of age) were introduced to and maintained on a KD or control diet for 33 days. During this period, breath acetone, plasma beta-HBA, blood glucose, and body weight were measured approximately every 4th day. A correlational analysis of breath acetone and plasma beta-HBA was conducted. RESULTS Br...
Journal of Liquid Chromatography & Related Technologies, 2019
Objectives: The objective of this study was the investigation of age-and sex-associations in a se... more Objectives: The objective of this study was the investigation of age-and sex-associations in a set of blood plasma metabolites in healthy male and female subjects. Methods: A comparison study design with male and female subjects of various ages was used. Metabolic profiling was performed using electrospray ionization tandem mass spectrometry that yielded 186 metabolite concentrations for each study participant. The key age-related metabolites were identified using an integrative analysis of absolute concentrations, metabolite ratios and the differential correlation of pairwise metabolite concentrations. All of the age-associated metabolites were adjusted prior to the analysis to account for differences in Body Mass Index (BMI). Results: A total of 236 plasma samples from 140 female and 96 male subjects aged 20 to 82 yearsold were collected and analyzed in the study. 13 and 14 age-associated metabolites (jrj > 0.33 and p < 6.6Â10 À5), 438 and 337 age-associated metabolite ratios (jrj > 0.37 and p < 3.5Â10 À6), and 5 and 10 core metabolites were discovered in the female and male groups, respectively. 80% of the metabolites displaying associations with age belonged to sphingolipids and phosphatidylcholines, and the two sexes shared less than 50% of the age-associated metabolites. Conclusion: The study found that changes in metabolite concentrations, metabolite ratios and differential correlations were age and sex-specific.
Multiple factors can help predict knee osteoarthritis (OA) patients from healthy individuals, inc... more Multiple factors can help predict knee osteoarthritis (OA) patients from healthy individuals, including age, sex, and BMI, and possibly metabolite levels. Using plasma from individuals with primary OA undergoing total knee replacement and healthy volunteers, we measured lysophosphatidylcholine (lysoPC) and phosphatidylcholine (PC) analogues by metabolomics. Populations were stratified on demographic factors and lysoPC and PC analogue signatures were determined by univariate receiver-operator curve (AUC) analysis. Using signatures, multivariate classification modeling was performed using various algorithms to select the most consistent method as measured by AUC differences between resampled training and test sets. Lists of metabolites indicative of OA [AUC > 0.5] were identified for each stratum. The signature from males age > 50 years old encompassed the majority of identified metabolites, suggesting lysoPCs and PCs are dominant indicators of OA in older males. Principal component regression with logistic regression was the most consistent multivariate classification algorithm tested. Using this algorithm, classification of older males had fair power to classify OA patients from healthy individuals. Thus, individual levels of lysoPC and PC analogues may be indicative of individuals with OA in older populations, particularly males. Our metabolite signature modeling method is likely to increase classification power in validation cohorts.
Menopause is an endocrine-related transition that induces a number of physiological and potential... more Menopause is an endocrine-related transition that induces a number of physiological and potentially pathological changes in middle-aged and elderly women. The intention of this research was to investigate the influence of menopause on the intricate relationships between major biochemical metabolites. The study involved metabolic profiling of 186 metabolic markers measured in blood plasma collected from 120 healthy female participants. We developed a method of network analysis using differential correlation that enabled us to detect and characterize differences in metabolites and changes in interrelationships in preand post-menopausal women. A topological analysis was performed on the differential network that uncovered metabolite differences in pre-and post-menopausal women. In this analysis, our method identified two key metabolites, sphingomyelins and phosphatidylcholines, which may be useful in directing further studies into menopause-specific differences in the metabolome, and how these differences may underlie the body's response to stress and disease following the transition from pre-to post-menopausal status for women.
Purpose: Anterior cruciate ligament tears (ACLT) are associated with a large knee effusion which ... more Purpose: Anterior cruciate ligament tears (ACLT) are associated with a large knee effusion which likely contains an early inflammatory response that may represent an early attempt at healing but ultimately leads to cartilage degeneration. Little is known about the composition of the synovial fluid (SF) in effusions after ACLT and whether it changes with time from injury. The purpose of this study is to determine the pattern of SF biomarkers after ACLT to test the hypotheses that it (a) differs from the pattern of SF biomarkers in knees with OA, (b) exhibits a response dependent on time-frominjury, and (c) varies based on the presence or absence of concomitant meniscus injury. Methods: SF was aspirated in the clinic from patients with ACLTs without any evidence for OA (N ¼ 13) and from patients with moderate to severe OA (N ¼ 16). Assessment of numerous pro-and anti-inflammatory cytokines, growth factors and chemokines was performed using multiplexed panel of 45 proteins. Nitric oxide (NO) was measured by Griess' reagent system.
To determine whether pre-existing nephropathy impacts urinary KIM-1 levels, urinary KIM-1 were me... more To determine whether pre-existing nephropathy impacts urinary KIM-1 levels, urinary KIM-1 were measured in patients with normal kidney filtration function but either with or without proteinuria. The reference intervals of urinary KIM-1 in adults with normal kidney filtration function but without urine proteinuria were established. Design and methods: 188 urine samples were obtained from adults with normal kidney filtration. 83 of the 188 showed negative urine protein, erythrocytes and leucocytes were used as normal controls. The remaining 105 samples showed at least one abnormal result suggesting possible preexisting nephropathy. Urinary KIM-1 concentrations were measured using an enzyme-linked immunosorbent assay. Urinary KIM-1 was normalized with urine creatinine concentration. The reference interval for urinary KIM-1 was determined by non-parametric methodology on 147 individuals. Results: The results showed significantly increased urinary KIM-1 concentration in protein positive (protein þ, erythrocyte þ/À, leucocyteþ/-) samples compared to controls (protein-, erythrocyte-, leucocyte-). Urinary KIM-1 concentrations were significantly higher when proteinuria was at trace concentration (0.25 g/L) and correlated with the severity of proteinuria. The creatinine normalized urinary KIM-1 was significantly higher when urine protein was 1 þ to 3þ (0.75-5 g/L). The reference interval for urinary KIM-1 was 0.00 (90%CI: 0-0) to 4.19 (90%CI: 3.11-5.62) μg/L, and for creatinine normalized urinary KIM-1 0.00 (90%CI: 0-0) to 0.58 (90%CI: 0.44-0.74) μg/mmol. Conclusions: Baseline urinary KIM-1 concentrations were increased when there was detectable urine protein and correlated with its severity. The urinary KIM-1 concentrations should be interpreted with consideration of urine protein levels in individual patients.
Background: Ketogenic diets are used therapeutically to treat intractable seizures. Clinically, i... more Background: Ketogenic diets are used therapeutically to treat intractable seizures. Clinically, it appears that the maintenance of ketosis is crucial to the efficacy of the diet in ameliorating seizures. To understand how ketosis and seizure protection are related, a reliable, noninvasive measure of ketosis that can be performed frequently with minimal discomfort is needed. Objective: The objective was to determine which index, breath acetone or urinary acetoacetate, is more strongly related to the plasma ketones acetoacetate and -hydroxybutyrate. Design: After fasting overnight for 12 h, 12 healthy adults consumed 4 ketogenic meals over 12 h. Blood, breath, and urine samples were collected hourly. Blood was analyzed for plasma acetoacetate and -hydroxybutyrate, breath for acetone, and urine for acetoacetate. Results: By the end of the 12-h dietary treatment, plasma acetoacetate, plasma -hydroxybutyrate, and breath acetone had increased 3.5-fold, whereas urinary acetoacetate increased 13-fold when measured enzymatically and 25-fold when measured with urinary ketone dipsticks. Plasma acetoacetate was best predicted by breath acetone (R 2 = 0.70, P < 0.0001). Plasma -hydroxybutyrate was equally predicted by breath acetone and urinary acetoacetate (R 2 = 0.54, P = 0.0040). Conclusions: Breath acetone is as good a predictor of ketosis as is urinary acetoacetate. Breath acetone analysis is noninvasive and can be performed frequently with minimal discomfort to patients. As an indicator of ketosis in epilepsy patients consuming a ketogenic diet, breath acetone may be useful for understanding the mechanism of the diet, elucidating the importance of ketosis in seizure protection, and ultimately, enhancing the efficacy of the diet by improving patient monitoring.
Females and males are known to have different abilities to cope with stress and disease. This stu... more Females and males are known to have different abilities to cope with stress and disease. This study was designed to investigate the effect of sex on properties of a complex interlinked network constructed of central biochemical metabolites. The study involved the blood collection and analysis of a large set of blood metabolic markers from a total of 236 healthy participants, which included 140 females and 96 males. Metabolic profiling yielded concentrations of 168 metabolites for each subject. A differential correlation network analysis approach was developed for this study that allowed detection and characterization of interconnection differences in metabolites in males and females. Through topological analysis of the differential network that depicted metabolite differences in the sexes, we identified metabolites with high centralities in this network. These key metabolites were identified as 10 phosphatidylcholines (
analysis (IBM SPSS Statistics, 19.01) was performed using repeated measures ANOVA (p<0.05). Resul... more analysis (IBM SPSS Statistics, 19.01) was performed using repeated measures ANOVA (p<0.05). Results: BR lead to a reduction in sCOMP after 24h for all interventions and the control condition (Fig.1). sCOMP recovered to baseline after the end of BR for all conditions (
To test whether type 2 diabetic patients have an elevated level of advanced glycation end-product... more To test whether type 2 diabetic patients have an elevated level of advanced glycation end-products (AGEs) and responsible for altered phosphatidylcholine metabolism, which we recently found to be associated with osteoarthritis (OA) and diabetes mellitus (DM), synovial fluid (SF) and plasma samples were collected from OA patients with and without DM. Hyperglycemia-related AGEs including methylglyoxal (MG), free methylglyoxal-derived hydroimidazolone (MG-H1), and protein bound N-(Carboxymethyl)lysine (CML) and N-(Carboxyethyl)lysine (CEL) levels were measured in both SF and plasma samples using liquid chromatography coupled tandem mass spectrometry methodology. The correlation between these AGEs and phosphatidylcholine acyl-alkyl C34:3 (PC ae C34:3) and C36:3 (PC ae C36:3) were examined. Eighty four patients with knee OA, including 46 with DM and 38 without DM, were included in the study. There was no significant difference in plasma levels of MG, MG-H1, CML, and CEL between OA patients with and without DM. However, the levels of MG and MG-H1, but not CML and CEL in SF were significantly higher in OA patients with DM than in those without (all p 0.04). This association strengthened after adjustment for age, body mass index (BMI), sex and hexose level (p<0.02). Moreover, the levels of MG-H1 in SF was negatively and significantly correlated with PC ae C34:3 (ρ =-0.34; p = 0.02) and PC ae C36:3 (ρ =-0.39; P = 0.03) after the adjustment of age, BMI, sex and hexose level. Our data indicated that the production of non-protein bound AGEs was increased within the OA-affected joint of DM patients. This is associated with changes in phosphatidylcholine metabolism and might be responsible for the observed epidemiological association between OA and DM.
To identify novel biomarker(s) for predicting advanced knee OA. Study participants were derived f... more To identify novel biomarker(s) for predicting advanced knee OA. Study participants were derived from the Newfoundland Osteoarthritis Study and the Tasmania Older Adult Cohort Study. All knee OA cases were patients who underwent total knee replacement (TKR) due to primary OA. Metabolic profiling was performed on fasting plasma. Four thousand and eighteen plasma metabolite ratios that were highly correlated with that in SF in our previous study were generated as surrogates for joint metabolism. The discovery cohort included 64 TKR cases and 45 controls and the replication cohorts included a cross-sectional cohort of 72 TKR cases and 76 controls and a longitudinal cohort of 158 subjects, of whom 36 underwent TKR during the 10-year follow-up period. We confirmed the previously reported association of the branched chain amino acids to histidine ratio with advanced knee OA (P = 9.3 × 10(-7)) and identified a novel metabolic marker-the lysophosphatidylcholines (lysoPCs) to phosphatidylchol...
In the early 1900s, medical practitioners recognized fasting as an effective method for controlli... more In the early 1900s, medical practitioners recognized fasting as an effective method for controlling seizures (1,2). The mechanism by which fasting suppressed seizures was initially explained as an alleviation of “intestinal intoxication,” which in turn was thought to be the cause of epilepsy (1).
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Papers by Sergei Likhodi