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Biomedical subjects

M C Sturkenboom

Publications and source records attributed to M C Sturkenboom.

At least 19 recordsLinked to original sources
PubMed2002

Incidence and prevalence of lower urinary tract symptoms suggestive of benign prostatic hyperplasia in primary care--the Triumph project.

OBJECTIVE: Benign prostatic hyperplasia (BPH) is one of the most common conditions associated with ageing in men. BPH often presents as lower urinary tract symptoms (LUTS) due to difficulties in voiding and irritability of the bladder. We conducted a retrospective cohort study within the Integrated Primary Care Information (IPCI) database, a general practitioners database in The Netherlands, to assess the incidence of LUTS suggestive of BPH (LUTS/BPH) in the general population. MATERIALS: Our study population comprised all males, 45 years or older who were registered for at least 6 months prior to start of follow-up. The study period lasted from 1 January 1995 to 31 December 2000. Cases of LUTS/BPH were defined as persons with a diagnosis of BPH, treatment or surgery for BPH, or urinary symptoms suggestive of BPH that could not be explained by other co-morbidity. RESULTS: The study cohort comprised 80,774 males who contributed 141,035 person-years of follow-up. We identified 2181 incident and 5605 prevalent LUTS/BPH cases. The overall incidence rate of LUTS/BPH was 15 per 1000 man-years (95% CI: 14.8-16.1). The incidence increased linearly (r(2) = 0.99) with age from three cases per 1000 man-years at the age of 45-49 years (95% CI: 2.4-3.6) to a maximum of 38 cases per 1000 man-years at the age of 75-79 years (95% CI: 34.1-42.9). After the age of 80 years, the incidence rate remained constant. For a symptom-free man of 46 years, the risk to develop LUTS/BPH over the coming 30 years, if he survives, is 45%. The overall prevalence of LUTS/BPH was 10.3% (95% CI: 10.2-10.5). The prevalence rate was lowest among males 45-49 years of age (2.7%) and increased with age until a maximum at the age of 80 years (24%). CONCLUSIONS: The incidence rate of LUTS/BPH increases linearly with age and reaches its maximum at the age of 79 years.

Age Distribution↗
PubMed2001

Indinavir crystallization around the loop of Henle: experimental evidence.

OBJECTIVE: To determine the probable site of the nephron and the plasma indinavir (IDV) concentration at which intrarenal IDV crystallization occurs. DESIGN: We performed in vitro crystallization experiments in IDV solutions simulating conditions found in the nephron. METHODS: To determine intrarenal IDV concentrations at which conditions in the nephron allow crystallization, several concentrations of IDV basic solutions (0-800 mM) were titrated from pH 4.0 to higher pH values until crystals formed within 1 minute. Based on the combination of pH and ionic strength at which crystals formed, we determined the site of the nephron at which this combination was first attained. Based on the capacity for concentration at that site, we were able to measure the corresponding plasma IDV concentration. RESULTS: Under conditions normally found at the proximal tubule (i.e., pH 6.7 and ionic strength of 200 mM), IDV crystallized at 200 mg/L. Under conditions applying to the loop of Henle, pH 7.4 and ionic strength of 200 mM, IDV crystallized at 125 mg/L, which would correspond to a plasma IDV concentration of 8 mg/L. CONCLUSIONS: IDV crystallization is most likely in the loop of Henle and may already start at plasma IDV concentrations as low as 8 mg/L. Increasing hydration does not reduce the risk of IDV crystallization in the loop of Henle but instead prevents IDV crystallization and aggregation in the lower urinary tract. It remains to be confirmed whether prevention of high IDV plasma concentrations will reduce the risk of IDV crystallization in the loop of Henle.

Crystallization↗
PubMed2001

Tendon disorders attributed to fluoroquinolones: a study on 42 spontaneous reports in the period 1988 to 1998.

OBJECTIVE: Fluoroquinolone antibiotics have been associated with tendinitis and tendon rupture. In this paper we report on the followup of 42 spontaneous reports of fluoroquinolone-associated tendon disorders. METHODS: This study is based on cases of fluoroquinolone-associated tendon disorders reported to the Netherlands Pharmacovigilance Foundation Lareb and the Drug Safety Unit of the Inspectorate for Health Care between January 1, 1988, and January 1, 1998. By means of a mailed questionnaire, we collected information on the site of injury, onset of symptoms, treatment, and course of the tendon disorder as well as information on possible risk factors and concomitant medication. RESULTS: Of 50 mailed questionnaires, 42 (84%) were returned. The data concerned 32 patients (76%) with tendinitis and 10 patients (24%) with a tendon rupture. Sixteen cases (38%) were attributed to ofloxacin, 13 (31%) to ciprofloxacin, 8 (19%) to norfloxacin, and 5 (12%) to pefloxacin. There was a male predominance, and the median age of the patients was 68 years. Most of the reports concerned the Achilles tendon, and 24 patients (57%) had bilateral tendinitis. The latency period between the start of treatment and the appearance of the first symptoms ranged from 1 to 510 days with a median of 6 days. Most patients recovered within 2 months after cessation of therapy, but 26% had not yet recovered at followup. CONCLUSION: These reports suggest that fluoroquinolone-associated tendon disorders are more common in patients over 60 years of age. Ofloxacin was implicated most frequently relative to the number of filled prescriptions in the Netherlands.

Adult↗
PubMed2001

The Dutch cohort of sildenafil users: baseline characteristics.

OBJECTIVE: To identify a Dutch cohort of sildenafil users and describe their baseline characteristics. PATIENTS AND METHODS: Each pharmacy in The Netherlands (n = 1571) was asked to identify prospectively the first 20 sildenafil prescriptions in their pharmacy over 1 year, and to complete and return a registration form. The collected data included patient characteristics, the details of the sildenafil prescription (date, prescriber, number of prescriptions, dosing), and the use of co-medication by the patient in the year preceding the sildenafil prescription. RESULTS: Data were collected from 4460 sildenafil prescriptions during the year under study, relating to 3477 individual patients. Most of the cohort had cardiovascular morbidity or diabetes. Sildenafil seems to have been used by a new, previously untreated population of patients with erectile dysfunction. In addition, 69 men were identified who could have been using nitrates and sildenafil concomitantly. CONCLUSION: A cohort of patients using sildenafil was identified and characterized; they appeared to be representative of sildenafil users in The Netherlands. This cohort will be followed prospectively to evaluate the medical status (particularly cardiovascular) of the patients with time.

Adult↗
PubMed2001

Demographic risk factors and lymphocyte populations in patients with tuberculosis and their healthy contacts.

SETTING: Campania, a southern region of Italy, and the Institute of Respiratory Diseases, Monaldi Hospital, University 'Federico II', Naples. OBJECTIVE: To evaluate clinical and socio-demographic risk factors for tuberculosis (TB) infection and/or disease. Peripheral blood lymphocytes from a sub-cohort of 19 patients and 53 contacts were studied by flow cytometry. DESIGN: A prospective study among patients with newly diagnosed pulmonary tuberculosis and their close contacts. RESULTS: A total of 90 patients and 277 contacts were enrolled. The prevalence of infection was 45% (95%CI 39-51%) among contacts. Age, sex, delay in diagnosis and treatment, cavitation on chest radiograph, cough, unwillingness to cover the mouth, and volume of air shared by close contacts and patients were investigated as potential risk factors for infection. Only delay in diagnosis of cases remained independently associated with an increased risk of infection (P < 0.0002), and hemoptysis was the only factor capable of reducing the delay significantly. The CD8+ CD28+ cytotoxic subset was significantly diminished in the patients (P < 0.001), whereas the CD8+ CD28- and CD8+ CD57+ (suppressor and NK-like subsets) were elevated (P < 0.001 and P = 0.04). CONCLUSIONS: These data show that delay in diagnosis of cases is a crucial factor for tuberculosis and that cytotoxic CD8+ cells play a primary role in immune response to tuberculosis.

Adult↗
PubMed2000

Multiple sclerosis and antecedent infections: a case-control study.

OBJECTIVES: To determine whether there is an excess of respiratory tract infections in the 5-week, 3-month, and 12-month periods before MS symptom onset and if there is an association between MS and a history of infectious mononucleosis (IM). BACKGROUND: The etiology of MS remains unknown, but infection is frequently suggested as a putative etiologic agent. Epidemiologic studies have produced inconsistent evidence for an etiologic role of respiratory tract infections (RTI) and IM in MS. METHODS: The authors performed a case-control study using the General Practice Research Database from the United Kingdom. There were 225 subjects with definite or probable MS, and 900 controls matched for age, sex, and physician practice. Using computerized patient records, the authors compared the mean rates of RTI per patient in the 5-week, 3-month, and 12-month periods before the date of onset of the first symptoms compatible with MS (index date). They also compared histories of IM. RESULTS: In all periods, an increased frequency of RTI was associated with a significantly increased risk of MS. A history of IM was associated with greater than five times the risk of MS (OR = 5.5 [95% CI 1.5 to 19.7]). CONCLUSIONS: These results support an association between a history of IM and subsequent MS. Respiratory tract infections may precipitate disease onset.

Adult↗
PubMed1999

Minocycline and lupuslike syndrome in acne patients.

BACKGROUND: Recently several case reports described the association between minocycline and lupuslike syndrome. Minocycline, one of the tetracyclines, is widely used to treat acne. We aimed to examine the association of exposure to minocycline and other tetracyclines with the development of lupuslike syndrome. METHODS: We conducted a nested case-control study in a cohort of 27 688 acne patients aged 15 to 29 years, using data automatically recorded on general practitioners' office computers in the United Kingdom. Controls were matched to cases on age, sex, and practice. The main outcome was lupuslike syndrome defined as the occurrence of polyarthritis or polyarthralgia of unknown origin, with negative rheumatoid factor or latex agglutination test, positive or unmeasured antinuclear factor, elevated or unmeasured erythrocyte sedimentation rate, and absence of or unmeasured antinative DNA antibody levels. RESULTS: We identified 29 cases and selected 152 controls. Current single use of minocycline was associated with an 8.5-fold (95% confidence interval [CI], 2.1-35) increased risk of developing lupuslike syndrome compared with non-users and past users of tetracyclines combined. The risk of past exposure to any of the tetracyclines was closely similar to nonuse (relative risk, 1.3; 95% CI, 0.5-3.3). Current use of doxycycline, oxytetracycline, or tetracycline combined was associated with a 1.7-fold (95% CI, 0.4-8.1) increase of risk. The risk increased with longer use. CONCLUSION: Current use of minocycline increased the risk of developing lupuslike syndrome 8.5-fold in the cohort of young acne patients. The effect was stronger in longer-term users. However, the absolute risk of developing lupuslike syndrome seems to be relatively low.

Acne Vulgaris↗
PubMed1999

Postmarketing surveillance based on electronic patient records: the IPCI project.

Researchers claim that data in electronic patient records can be used for a variety of purposes including individual patient care, management, and resource planning for scientific research. Our objective in the project Integrated Primary Care Information (IPCI) was to assess whether the electronic patient records of Dutch general practitioners contain sufficient data to perform studies in the area of postmarketing surveillance studies. We determined the data requirements for postmarketing surveillance studies, implemented additional software in the electronic patient records of the general practitioner, developed an organization to monitor the use of data, and performed validation studies to test the quality of the data. Analysis of the data requirements showed that additional software had to be installed to collect data that is not recorded in routine practice. To avoid having to obtain informed consent from each enrolled patient, we developed IPCI as a semianonymous system: both patients and participating general practitioners are anonymous for the researchers. Under specific circumstances, the researcher can contact indirectly (through a trusted third party) the physician that made the data available. Only the treating general practitioner is able to decode the identity of his patients. A Board of Supervisors predominantly consisting of participating general practitioners monitors the use of data. Validation studies show the data can be used for postmarketing surveillance. With additional software to collect data not normally recorded in routine practice, data from electronic patient record of general practitioners can be used for postmarketing surveillance.

Family Practice↗
PubMed1998

[Lipodystrophy and 'buffalo hump' during treatment with HIV protease inhibitors].

In three patients, a 36-year-old HIV seropositive homosexual man and two women aged 35 and 59 years who had acquired HIV infection through heterosexual contact, signs of lipodystrophy developed after prolonged anti-HIV triple therapy. The observed syndrome is seen after prolonged use of HIV protease inhibitors: it is characterized by peripheral fat wasting, central fat accumulation, hyperlipidaemia and insulin resistance. Typically the subcutaneous fatty tissue disappears resulting in prominent zygomata, veins and muscles and thinning of extremities and buttocks. In addition to abdominal fat accumulation, there have been reports on the occurrence of a dorsocervical fat pad, the so-called buffalo hump. Lipodystrophy caused by protease inhibitors is a risk factor for cardiovascular disease. Recognition of the syndrome is essential for adequate follow-up and possible treatment.

Adult↗
PubMed1998

Postmenopausal estrogen replacement therapy and the risk of developing systemic lupus erythematosus or discoid lupus.

OBJECTIVE: There is evidence that estrogens play a role in the etiology of systemic lupus erythematosus (SLE), but this has not yet been shown for discoid lupus. We examined the association of postmenopausal estrogen use with the development of SLE and discoid lupus. METHODS: We did a case-control evaluation, using the UK based General Practice Research Database. We analyzed 41 cases with SLE, 34 cases with discoid lupus, and 295 age, sex and practice matched controls, and estimated relative risk estimates (odds ratios) in relation to estrogen exposure duration as well as total cumulative dose and estrogen type (alone or combined with progestogens). RESULTS: While short term estrogen exposure was not associated with increased risk, the risk of developing SLE (adjusted OR 2.8; 95% CI 0.9-9.0) or discoid lupus (adjusted OR 2.8; 95% CI 1.0-8.3) was significantly increased among current users who were exposed for 2 or more years. The adjusted RR estimate comparing longer term estrogen users and nonusers for all cases (SLE and discoid lupus combined) was 2.8 (95% CI 1.3-5.8; p < 0.01). A difference was found between longterm users of estrogens alone (OR 5.3; 95% CI 1.5-18.6) and those who used estrogens combined with progestogens (OR 2.0; 95% CI 0.8-5.0), compared to nonusers. CONCLUSION: Our findings suggest that longer term use of postmenopausal estrogens plays a role in the etiology of both SLE and discoid lupus. There is a suggestion that progestogens may reduce the effect of estrogens on these autoimmune disorders.

Aged↗
PubMed1996

Taste loss to terbinafine: a case-control study of potential risk factors.

1. To identify risk factors associated with taste loss to terbinafine, we performed a case-control study of 87 reports of probably terbinafine-induced taste loss and 362 controls on terbinafine without taste loss, who had filled prescriptions from the same pharmacy and GP. Data on general health, diet, alcohol, smoking, drug use and medical history were collected by means of a self-administered questionnaire. 2. The mean latent period between first intake of terbinafine and taste loss was 35 days. Most patients recovered within 4 months after discontinuation. Cases were significantly older than controls. The odds ratio of taste loss in patients of 65 years and older was 4.4 in comparison with persons younger than 35 years of age (95% CI: 1.4-16.1). The risk in persons with a body mass index (BMI) below 21 kg m-2 was 4.4 times higher than in those with a BMI of more than 27 kg m-2 (95% CI: 1.6-14.2). The risk of taste loss in patients of 55 years and older with a BMI below 21 kg m-2 was 12.8 times higher than that in patients below 35 years of age (95% CI: 1.9-88.6). 3. A low BMI, a history of taste loss, and ageing are risk factors for developing taste loss to terbinafine. Prescription of this drug to elderly patients with low BMI and low daily intake of nutrients requires careful follow-up.

Adult↗
PubMed1995

The role of pharmacists in the recruitment of a cohort for postmarketing surveillance. A case study of acitretin in The Netherlands.

In October 1990, a recall procedure was issued regarding the drug acitretin. The recommended post-therapy contraception period after acitretin therapy was extended from 2 months to 2 years. For a postmarketing surveillance study, we recruited a cohort from the source population of women aged 15-45 years who were exposed to acitretin. Recruitment occurred through dermatologists, and pharmacists plus dispensing general practitioners. We describe the speed of and the response to the recruitment procedures, and the representativeness of the recruited cohort. We also studied whether the individuals who gave informed consent would have preferred to be recruited by either dermatologists or pharmacists, and whether the information obtained from pharmacists and dispensing general practitioners was valid. This study revealed that pharmacists and dispensing general practitioners (drug dispensers) recruited their subjects rapidly, with no or little selection; they attained a 42% response. Dermatologists recruited their subjects slowly and selectively; they attained a 24% response. The majority of women (60%) recruited by dermatologists would have given their informed consent if they would have been recruited by their pharmacists. Drug dispensers are essential contributors to the recruitment of a study population. We do advise that such recruitment for a postmarketing surveillance study occurs by means of a collaboration between pharmacists and physicians.

Acitretin↗
PubMed1995

Severe limb defects and craniofacial anomalies in a fetus conceived during acitretin therapy.

We describe a 20-week-old fetus with multiple congenital anomalies exposed to acitretin in the first trimester of pregnancy. Acitretin and its ethylester etretinate are both vitamin A congeners; drugs of this group are well-known teratogenic agents. Since the marketing of acitretin only one report on human teratogenicity associated with acitretin has been published. The present male fetus showed severe symmetric anomalies of upper and lower limbs, craniofacial anomalies, ear anomalies, and an atrioventricular septal defect (ASD). Although the craniofacial anomalies resemble the abnormalities described in classical "retinoic acid embryopathy," limb anomalies were seldomly reported after maternal use of vitamin A congeners. However, in laboratory animals limb defects were frequently observed after retinoid exposure in utero. This case emphasizes again that extreme care and precaution are needed before prescribing a potentially teratogenic drug to a fertile woman.

Abnormalities, Drug-Induced↗
PubMed1995

Vulvo-vaginal candidiasis associated with acitretin.

The aim of this study was to estimate the risk of vulvo-vaginal candidiasis among the users of acitretin. The incidence rate ratio of vulvo-vaginal candidiasis was estimated in a cohort of acitretin users by using prescription sequence analysis. Study subjects were 196 women between 15 and 45 years of age, exposed to acitretin in 1990. Prescriptions of drugs for treatment of vulvo-vaginal candidiasis were used as proxy for the occurrence of vulvo-vaginal candidiasis. Validation of the proxy drug was performed by record linkage of pharmacy and medical records. In addition to the risk estimation by incidence rate ratios a case-crossover study with patient-stratified logistic regression analysis was performed to control for distortion due to individual differences in contribution of exposure time. The positive predictive value of the proxy drug for vulvo-vaginal candidiasis ranged between 57 and 100%, the sensitivity was 87% and the specificity estimated 99%. The crude incidence rate ratio for vulvo-vaginal candidiasis following acitretin exposure was 2.8 (CI95%: 1.1-7.1). The pooled Mantel-Haenszel incidence rate ratio was 3.3 (CI95%: 1.1-9.6) after stratification for accumulated level of exposure. Patient-stratified analysis on the subgroup of cases (n = 15) revealed an odds ratio of 6.5 (CI95%: 2.3-18.2). This study strongly suggests that the higher occurrence of vulvo-vaginal candidiasis during acitretin exposure is attributable to the drug.

Acitretin↗
PubMed1994

Communicating a drug alert. A case study on acitretin in The Netherlands.

In October 1990, a recall procedure was initiated for the teratogenic drug acitretin, and the recommended post-therapy contraception period after acitretin therapy was extended from 2 months to 2 years due to the possibility of its conversion to the lipophilic compound etretinate. The aim of the present study was to evaluate the communication procedures and their effects as a drug alert from the health authorities, the pharmaceutical company and professional associations of health professionals to the population at risk. A model was used to evaluate communication between three hierarchical levels. Data were obtained via semi-structured interviews and structured questionnaires. Communication procedures were evaluated according to channel characteristics and by analysis of their contents. The effect was measured as whether the drug dispensers identified acitretin users, contacted physicians, and whether physicians communicated in person with the population at risk. The penetration of direct mail from the health authorities and from the pharmaceutical company ranged from 97-98% and 65-94% at Level 2 (health professionals). The population at risk was informed via personal communication with health professionals, and/or the mass media. Of the women at risk, 19% were contacted by a dermatologist, 30% by their GP, and 39% by the pharmacist. 35% was never informed by any health professional. The Dutch health care system is adequately equipped for effective communication between health authorities, pharmaceutical industry and health professionals.(ABSTRACT TRUNCATED AT 250 WORDS)

Acitretin↗
PubMed1994

Inability to detect plasma etretinate and acitretin is a poor predictor of the absence of these teratogens in tissue after stopping acitretin treatment.

1. Concentrations of etretinate, acitretin and its main metabolite 13-cis-acitretin were measured in plasma and subcutaneous fat samples from 37 women of childbearing age exposed to acitretin before November 1990. Twenty of the women still used acitretin and 17 had stopped therapy for a period ranging from 1 to 29 months. 2. The prevalences of detectable etretinate concentrations were 45% and 83% in plasma and subcutaneous tissue, respectively, among current acitretin users and 18% and 86% among those who had stopped acitretin therapy. Thus, inability to detect plasma etretinate is a poor predictor of the absence of etretinate in fat. 3. Acitretin and/or etretinate were detectable in fat and in some cases in plasma from women who had ceased acitretin therapy for up to 29 months. 4. We suggest that (cis)-acitretin and etretinate should be monitored in subcutaneous tissue when plasma measurements are negative. The recommended contraception period of 2 years after cessation of acitretin therapy should be reconsidered to avoid the risk of teratogenicity.

Acitretin↗
PubMed1993

Differential effects of spermine and its analogues on the structures of polynucleotides complexed with ethidium bromide.

The interactions of spermine and polyamine analogues with synthetic polynucleotides of various base sequences complexed with ethidium bromide (EB) were investigated using measurements of fluorescence intensity and steady-state fluorescence polarization. Spermine and polyamine analogues displaced some but not all of the EB bound to poly(dA-dT).poly(dA-dT) or poly(dG-dC).poly(dG-dC), suggesting that polyamines may stabilize these polynucleotides in a conformation with reduced affinity for EB. Modifications of the aliphatic backbone of spermine have pronounced effects on its ability to displace EB from poly(dA-dT).poly(dA-dT) but not from poly-(dG-dC).poly(dG-dC). Spermine and some but not all of the polyamine analogues caused fluorescence depolarization when they interacted with the complex of EB and poly(dA-dT).poly-(dA-dT). Neither spermine nor any of the analogues, however, induced fluorescence depolarization in the complex of EB with poly(dG-dC).poly(dG-dC) or poly(dA).poly(dT). This suggests that spermine and some spermine analogues induce structural changes specific to alternating A-T sequences.

Ethidium↗