Papers by Richard Dekhuijzen
Respiratory Medicine, 2009
Background: Increased oxidative stress and bronchial inflammation are important mechanisms in the... more Background: Increased oxidative stress and bronchial inflammation are important mechanisms in the pathophysiology of COPD. Aim: To investigate whether treatment with the inhaled corticosteroid fluticasone propionate (FP) or the anti-oxidative agent N-acetylcysteine (NAC) are effective in primary care patients. Methods: The study was a 3-year placebo-controlled randomised controlled trial preceded by a 3-month washout and 2-week prednisolone pre-treatment. Patients were (ex-)smokers with chronic bronchitis or COPD. Interventions were inhaled FP 500 mg b.i.d., oral NAC 600 mg o.d., or placebo. Exacerbation rate and quality of life measured with the Chronic Respiratory Questionnaire (CRQ) were the primary outcomes, FEV 1 decline and respiratory symptoms secondary outcomes. Results: 286 patients recruited from 44 general practices were randomised. Exacerbation rate was 1.35 times higher for NAC (p Z 0.054) and 1.30 times higher for FP (p Z 0.095) compared with placebo. CRQ total scores did not differ between NAC (p Z 0.306) or FP (p Z 0.581) treatment compared to placebo. Annual postbronchodilator FEV 1 decline was 64 mL [SD 5.4] for NAC [p Z 0.569 versus placebo], 59 mL [SD 5.7] for FP [p Z 0.935], and 60 mL [SD 5.4] for placebo.
Respiration, 2008
In contrast to static inspiratory parameters such as vital capacity and inspiratory capacity, inf... more In contrast to static inspiratory parameters such as vital capacity and inspiratory capacity, information on forced inspiratory volume in 1 s (FIV(1)) in patients with chronic obstructive pulmonary disease (COPD) is limited. It was the aim of this study to investigate the influence of the preceding expiratory manoeuvre and the optimal number of manoeuvres on FIV(1) values. In 169 patients with COPD, FIV(1) manoeuvres were performed after a forced (FIV(1)-Fe) and a slow (FIV(1)-Se) expiration. To investigate the optimal number of the FIV(1)-Se manoeuvres, 8 attempts were performed. The variability of FIV(1)-Fe was greater than that of FIV(1)-Se. The mean difference between FIV(1)-Se and FIV(1)-Fe was 0.21 litres (p < 0.01) and dependent on the Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage. The higher the GOLD stage, the greater the difference between the 2 techniques. The correlation coefficient between FIV(1)-Se and FIV(1)-Fe was high (r = 0.89, p = 0.01), but there was a poor agreement between these parameters (limits of agreement -0.52 to 0.94 litres). Five manoeuvres were needed to obtain an optimal FIV(1)-Se. There was no association with the GOLD stage. In COPD patients, FIV(1)-Se are less variable than FIV(1)-Fe, the agreement between the 2 manoeuvres is poor, and at least 5 FIV(1)-Se manoeuvres are needed to get an acceptable FIV(1). This holds for all GOLD stages.
Clin Microbiol Infect, 2009
Nontuberculous mycobacteria are environmental, opportunistic pathogens whose role in human diseas... more Nontuberculous mycobacteria are environmental, opportunistic pathogens whose role in human disease is increasingly recognized, especially regarding the rapid growing mycobacteria (RGM). RGM are recovered from various environmental sources, both natural and manmade. In water systems, RGM can survive by forming biofilms and by interactions with protozoa. The presence and species diversity of RGM in water is influenced by temperature, pH and the chemical quality of the water, as well as the availability of nutrients, although the exact correlations remain controversial. Despite their omnipresence in environmental sources, the actual transmission of RGM to humans, with subsequent clinical disease, has rarely been proven. However, outbreaks as a result of contaminated water sources have been reported, although accidental presence in clinical samples cannot always be excluded. In this setting, the presence of RGM does not necessarily indicate a causal relationship with clinical disease; accidental presence in clinical samples cannot always be excluded.
Primary Care Respiratory Journal Journal of the General Practice Airways Group, Jun 1, 2009
Mild persistent asthma should be treated with continuous inhaled corticosteroids (ICS), which red... more Mild persistent asthma should be treated with continuous inhaled corticosteroids (ICS), which reduces exacerbations of disease, controls symptoms and reduces bronchial mucosal inflammation. Most patients can be controlled with low dosage ICS (≤ 500 mcg/day beclometasone or equivalent) and there is limited benefit from further escalating dosages. There is some evidence of additional benefit of early treatment in terms of better longer term control of symptoms, but not alteration of the natural history of the disease. Withdrawal of ICS therapy results in rapid relapse of symptoms. Although some studies have suggested that intermittent therapy with ICS is not detrimental to asthma control, in the absence of any studies investigating the long term clinical, functional and pathophysiological differences between regular and intermittent therapy, the former continues to be recommended in guidelines. In patients well controlled on low/moderate dosages of ICS there is little benefit of adding any other medication and no rationale for commencing combination therapy routinely as first line controller therapy. There is no evidence that ICS or any other medication prevents the occurrence of asthma, and scanty evidence that the decline in lung function associated with asthma is arrested to any significant degree by ICS therapy. ICS has variable effects on features of airways remodelling but the long term physiological consequences of these effects, if any, are as yet unknown.
The European Respiratory Journal, Aug 1, 2001
Int J Tuberc Lung Dis, 2008
The Netherlands. To investigate the frequency of resistance to second-line drugs among multidrug-... more The Netherlands. To investigate the frequency of resistance to second-line drugs among multidrug-resistant tuberculosis (MDR-TB) cases and its correlation with patients' geographic origin. Retrospective laboratory database study of multidrug-resistant Mycobacterium tuberculosis complex strains isolated in the Netherlands between January 1993 and October 2007. We found 153 patients with MDR-TB, of whom 18 (12%) were native Dutch. Complete second-line drug susceptibility testing was performed for 131 MDR-TB patients. Resistance to second-line drugs was noted in primary samples of 28 (21%) MDR-TB patients. Resistance to a single second-line drug was most frequent (24/28 [86%]; 9 to prothionamide [PTH], 6 to para-aminosalicylic acid, 4 to amikacin [AMK], 4 to ciprofloxacin and 1 to cycloserine). Four MDR-TB patients had strains resistant to multiple second-line drugs; two were extensively drug-resistant M. bovis. In MDR-TB patients of European and Central Asian origin, resistance to second-line drugs was most frequent and involved the widest range of drugs. PTH resistance was frequent among African and American MDR-TB patients, while AMK resistance was frequent among South-East Asians. Resistance to second-line drugs is infrequent among MDR-TB patients in the Netherlands. Most second-line drug resistance is recorded among immigrants, with substantial differences in second-line drug resistance in MDR-TB patients originating from different geographical areas.
Journal of Bacteriology, 2009
The esat-6 and cfp-10 genes are essential for virulence in Mycobacterium tuberculosis. Among nont... more The esat-6 and cfp-10 genes are essential for virulence in Mycobacterium tuberculosis. Among nontuberculous mycobacteria, we found these genes only in M. kansasii, M. szulgai, M. marinum, and M. riyadhense, with unique sequences. This adds a phylogenetic and taxonomical characteristic and may represent a virulence factor for nontuberculous mycobacteria.
International Journal of Rehabilitation Research, Feb 1, 1991
In target-flow inspiratory muscle training (TF-IMT), the generated inspiratory mouth pressure and... more In target-flow inspiratory muscle training (TF-IMT), the generated inspiratory mouth pressure and the duration of the inspiration and expiration are standardized to given an adequate training stimulus to the inspiratory muscles. The acute effects of TF-IMT on the efficiency of breathing were studied in a group of 12 COPD patients with a ventilatory limitation of their exercise capacity (mean age 58, mean FEV1 46.2% of predicted) and in 15 normal subjects (mean age 30). Also, the effect of a 10 week period of TF-IMT on the maximal inspiratory mouth pressure (PImax) in the COPD patients was measured. After an unloaded baseline period, the subjects started to inspire through a target-flow device during 15 min, followed by a recovery phase of 5 min. During TF-IMT minute ventilation (VE) decreased only in the COPD group. The ventilatory equivalent for O2 (VE/VO2) and the dead space to tidal volume ratio (VD/VT) decreased in both groups. During recovery, VE, VE/VO2 and VD/VT remained below baseline values in the COPD group, but not in the control group. PCO2 and lactate concentrations did not change during TF-IMT. After the 10 week training period, PImax [means) (SD] increased from 5.7(2.2) to 8.2(2.7) kPa (p less than 0.05). The results indicate that with standardized TF-IMT, the inspiratory muscles can be trained effectively in COPD patients with a ventilatory limitation. The persistence of the decrease in VE, VE/VO2 and VD/VT after a training session may be an additional beneficial effect of TF-IMT.
International Journal of Systematic and Evolutionary Microbiology, 2009
Eighteen isolates of a nonchromogenic, slowly growing, non-tuberculous species of the genus Mycob... more Eighteen isolates of a nonchromogenic, slowly growing, non-tuberculous species of the genus Mycobacterium were cultured from respiratory specimens obtained over the last eight years from 17 patients in the Netherlands. These isolates were grouped because they revealed a unique 16S rRNA gene sequence and were related to Mycobacterium xenopi. None of the 17 patients met the American Thoracic Society diagnostic criteria for non-tuberculous mycobacterial disease, which distinguishes the novel isolates from the related species, M. xenopi. A polyphasic taxonomic approach, including identification by biochemical and phenotypical analysis, hsp65 gene sequencing and PCR restriction enzyme pattern analysis, and sequence analyses of the rpoB gene and 16S-23S internal transcribed spacer supported the separate species status of the novel isolates. The name Mycobacterium noviomagense sp. nov. is proposed for the novel strains. The type strain is NLA000500338 T (5DSM 45145 T 5CIP 109766 T ). A more distinctive taxonomy of NTM is a prerequisite for the assessment of their clinical relevance.
Eur Resp J, 2004
Oxidative stress has been implicated in the pathogenesis and progression of chronic obstructive p... more Oxidative stress has been implicated in the pathogenesis and progression of chronic obstructive pulmonary disease.
Int J Syst Evol Microbiol, 2009
The Mycobacterium avium complex (MAC) consists of four recognized species, Mycobacterium avium, M... more The Mycobacterium avium complex (MAC) consists of four recognized species, Mycobacterium avium, Mycobacterium colombiense, Mycobacterium intracellulare and Mycobacterium chimaera, and a variety of other strains that may be members of undescribed taxa. We report on two isolates of a scotochromogenic, slowly growing, non-tuberculous Mycobacterium species within the M. avium complex from a lymph node and an infected wound after a dogbite of separate patients in The Netherlands. The extrapulmonary infections in immunocompetent patients suggested a high level of virulence. These isolates were characterized by a unique nucleotide sequence in the 16S rRNA gene, 99% similar to Mycobacterium colombiense, and the MAC-Q 16S-23S internal transcribed spacer (ITS) sequence. Sequence analyses of the hsp65 gene revealed 97% similarity to M. avium. The rpoB gene sequence was 98% similar to M. colombiense. Phenotypically, the scotochromogenicity, positive semi-quantitative catalase and heat-stable catalase tests, negative tellurite reductase and urease tests and susceptibility to hydroxylamine and oleic acid set these isolates apart from related species. High-performance liquid chromatography analysis of cell-wall mycolic acid content revealed a unique pattern, related to that of M. avium and M. colombiense. Together, these findings supported a separate species status within the Mycobacterium avium complex. We propose elevation of scotochromogenic M. avium complex strains sharing this 16S gene and MAC-Q ITS sequence to separate species status, for which the name Mycobacterium vulneris sp. nov. is proposed. The type strain is NLA000700772T (=DSM 45247T=CIP 109859T).
Clin Microbiol Infect, 2009
European Journal of Clinical Pharmacology, May 19, 2004
Ned Tijdschr Geneeskd, 2008
The second revised guideline 'Asthma in adults' from the Dutch College of General... more The second revised guideline 'Asthma in adults' from the Dutch College of General Practitioners has been published. Several lacunae in the scientific axiomatisation of the approach to asthma expose discrepancies, with regard to the diagnostic and therapeutic approach, particularly during a comparison of the guideline with international guidelines. According to the guideline, treatment of asthma should include the general practitioner seeing the patient on a regular basis. This approach implies that the doctor, and not the patient, still plays a pivotal role during the treatment of asthma, which sometimes makes the treatment less patient friendly than necessary. Hopefully, the next revision will show a little more consideration for the desires of the patient.
B24. NON-TUBERCULOUS MYCOBACTERIA: BENCH TO BEDSIDE, 2010
B24. NON-TUBERCULOUS MYCOBACTERIA: BENCH TO BEDSIDE, 2010
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Papers by Richard Dekhuijzen