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B C Tanis

Publications and source records attributed to B C Tanis.

17 recordsLinked to original sources
PubMed2006

Carrier diagnostics and prevention of hemoglobinopathies in early pregnancy in The Netherlands: a pilot study.

BACKGROUND: We have offered, for the first time in The Netherlands, carrier diagnostics for hemoglobinopathies (HbP) to early pregnant women. The aim of this study was to establish whether carrier analysis would be welcome by the public and feasible at the outpatient level. METHOD: One hundred and thirty-nine randomly selected women were informed and offered basic carrier diagnostics at the first pregnancy control. RESULTS: Carrier diagnostics was accepted by 136 women (97.8%). The population consisted of 31% of recent immigrants and 69% of native Dutch. One carrier of HbS and one of beta-thalassemia were found, both among the group of the recent immigrants. In both cases, partners were tested excluding a couple at risk. In addition, five carriers of alpha(+)-thalassemia were diagnosed at the molecular level, one of them in the native Dutch population. Basic carrier analysis was done both at the Hospital Laboratory and at the Reference Laboratory. No discrepancies were found. CONCLUSIONS: This pilot study shows that (1) as predicted the prevalence of risk-related HbP and of alpha(+)-thalassemia is high in the immigrant population. (2) The compliance with carrier analysis in both native Dutch and immigrants is virtually total and (3) carrier diagnosis in early pregnancy and partner analysis in Hospital Laboratories is possible and is an effective tool for primary prevention of HbP in The Netherlands.

Adult↗
PubMed2005

Prothrombotic conditions, oral contraceptives, and the risk of ischemic stroke.

BACKGROUND: The role of inherited prothrombotic conditions, including factor V Leiden (FV G1691A), prothrombin G20210A, and the methylenetetrahydrofolate reductase (MTHFR) C677T genotype, in the pathogenesis of ischemic stroke is not well established. The effects of these factors may be potentiated by the use of oral contraceptives, analogous to observations in venous thrombosis. METHODS: Patients (n = 193) were women aged 20-49 years with ischemic stroke. Controls (n = 767) were women without arterial thrombosis stratified for age, calendar year of the index event, and residence. The relative risk of ischemic stroke was estimated with unconditional logistic regression, adjusted for stratification variables. FINDINGS: Factor V Leiden and MTHFR 677TT were more common in patients than in controls [odds ratio (OR): 1.8; 95% confidence interval (CI): 0.9-3.6 respectively OR: 1.5; 95% CI: 0.9-2.6]. The frequency of prothrombin G20210A was similar in cases and controls. Carriers of FV Leiden using oral contraceptives had a 11.2-fold (95% CI: 4.3-29.0) higher risk of ischemic stroke than women without either risk factor. Women with MTHFR 677TT using oral contraceptives had a 5.4-fold (95% CI: 2.4-12.0) higher risk than women without these risk factors. INTERPRETATION: These data suggest that carriers of FV Leiden or MTHFR 677TT who use oral contraceptives have an increased risk of ischemic stroke. When these findings are confirmed, a cost-effectiveness analysis should indicate whether ischemic stroke could be prevented with genetic testing before the start of oral contraceptives.

Adult↗
PubMed2004

Folate, homocysteine levels, methylenetetrahydrofolate reductase (MTHFR) 677C --> T variant, and the risk of myocardial infarction in young women: effect of female hormones on homocysteine levels.

In young women data are limited about the association between myocardial infarction (MI) and hyperhomocysteinemia, low folate or methylenetetrahydrofolate reductase (MTHFR) genotypes. The effect of oral contraceptive (OC) use on plasma homocysteine levels is not clear. We assessed the association between hyperhomocysteinemia, low folate, MTHFR 677TT mutation and risk of MI, and we investigated the effect of OC use on homocysteine levels in controls. In 181 patients with a first MI and 601 controls 18-49 years of age from a population-based case-control study, non-fasting blood samples were available. The homozygote mutant allele (TT) was detected in 12% of the patients and in 10% of controls. The odds ratio (OR) for MI in TT patients compared with the wild-type (CC) controls was 1.3 [95% confidence interval (CI) 0.8, 2.3]. For all MTHFR genotypes combined, the OR for MI in the lowest quartile of folate (<5.4 nmol L-1) compared with the highest quartile (>10.4 nmol L-1) was 3.0 (95% CI 1.7, 5.1). A 2-fold increased risk of MI was found in women with the TT genotype who had folate levels below the median of 7.4 nmol L-1 compared with CC genotype and folate levels above the median (OR = 2.0; 95% CI 1.0, 3.7). Mean homocysteine levels were 12.2 micromol L-1 in OC users and 12.3 micromol L-1 in non-users. Only at the 97.5 percentile (cut-off 21.0 micromol L-1) was the adjusted OR for higher vs. lower homocysteine levels increased by 2.8-fold (95% CI 1.2, 6.8). Low folate is a risk factor for MI, particularly in women with the MTHFR 677TT genotype. Homocysteine levels were not influenced by OC use.

Adolescent↗
PubMed2003

The RATIO study: oral contraceptives and the risk of peripheral arterial disease in young women.

With regard to oral contraceptives, much research has concentrated on venous thrombosis and on the coronary and cerebral forms of atherosclerotic disease, while peripheral arterial disease (PAD) has received little attention. In this case-control study, we assessed oral contraceptive use and the risk of PAD in young women using a population-based case-control study. The women were 18-49 years of age, and had been admitted to a collaborating hospital between January 1990 and October 1995, and had a diagnosis of PAD. Participants were patients with PAD (n = 152), and control women (n = 925), identified by random digit dialing. The diagnosis of PAD was based almost exclusively on intra-arterial angiography. Patients and control subjects filled out the same structured questionnaire, which included questions on medical history, cardiovascular risk factors, and contraceptive use. The adjusted odds ratio for PAD in women using any type of oral contraceptives vs. no use, was 3.8 (95% CI 2.4-5.8). When first generation oral contraceptive use was compared with no use, the odds ratio was 8.7 (95% CI 3.6-21.3). For second and third generation oral contraceptives, the adjusted odds ratios (compared with non-users) were 2.6 (95% CI 1.4-4.9) and 3.0 (95% CI 1.4-6.6), respectively. This is the first study on oral contraceptive use and PAD in humans. All types of oral contraceptives were associated with an increased risk of PAD.

Adult↗
PubMed2003

Estrogens, progestogens and thrombosis.

Hundreds of millions of women worldwide use either oral contraceptives or postmenopausal hormone replacement. The use of oral contraceptives leads to an increased risk of venous thrombosis, of myocardial infarction, of stroke and of peripheral artery disease, the risks of which are highest during the first year of use. Women with coagulation abnormalities have a higher risk of venous thrombosis when they use oral contraceptives (or postmenopausal hormones) than women without these abnormalities. The risk of venous thrombosis is also higher for preparations containing desogestrel or gestodene (third-generation progestogens) than for those containing levonorgestrel (second-generation progestogens). A previous thrombosis as well as obesity also increase the risk of oral contraceptive-related thrombosis. Hormone replacement therapy increases the risk of venous thrombosis, and has no beneficial, and possibly even a detrimental, effect on the risk of arterial disease. The risk of arterial disease in oral contraceptive users and users of hormone replacement therapy is at most weakly affected by the presence of prothrombotic abnormalities.

Contraceptives, Oral↗
PubMed2002

The relation between Helicobacter pylori and atherosclerosis cannot be explained by a high homocysteine concentration.

BACKGROUND: Recent studies have suggested that a chronic infection with Helicobacter pylori might be an independent risk factor for atherosclerosis. However, a direct role in atherogenesis is not plausible, since the bacterium has not been isolated from atherosclerotic lesions. An indirect mechanism that could link H. pylori with atherosclerosis might be through an increase in plasma homocysteine concentration caused by deficiencies of vitamin B12 and folate in plasma. MATERIALS AND METHODS: In 150 female patients with peripheral arterial disease (PAD) and in 412 healthy control women from a nation-wide population-based case-control study, blood samples were collected to determine the antibody titre against H. pylori and to measure plasma homocysteine, folate and vitamin B12 levels. First, the odds ratio for PAD in women with a positive antibody titre against H. pylori was calculated and adjusted for homocysteine level. Secondly, mean concentrations of vitamin B12, folate and homocysteine were compared in healthy controls with a positive or negative antibody titre against H. pylori. Thirdly, the relation between H. pylori and PAD in individuals with a normal or high homocysteine level was investigated. RESULTS: A positive immunoglobulin G antibody titre against H. pylori was found in 42% of the PAD patients and in 27% of the controls. The age- and socio-economic-status (SES) adjusted odds ratio for PAD was 1.5 (95%CI; 1.0-2.2). Additional adjustment for homocysteine plasma concentration did not essentially change the odds ratio. Secondly, among the healthy controls, the homocysteine plasma concentration did not depend on the immunoglobulin G titre, neither did the folate plasma concentration. The concentration of vitamin B12 was slightly higher in women with a positive titre. Thirdly, H. pylori infection was a risk factor for PAD in subjects with a normal homocysteine concentration [OR 2.0 (95%CI 1.3-3.1)]. CONCLUSIONS: This study shows a relationship between a positive immunoglobulin G antibody titre against H. pylori and PAD in young women. Moreover, this study does not support the hypothesis that H. pylori infection is related to atherosclerosis via an increase in plasma homocysteine concentration.

Adolescent↗
PubMed2001

Oral contraceptives and the risk of myocardial infarction.

BACKGROUND: An association between the use of oral contraceptives and the risk of myocardial infarction has been found in some, but not all, studies. We investigated this association, according to the type of progestagen included in third-generation (i.e., desogestrel or gestodene) and second-generation (i.e., levonorgestrel) oral contraceptives, the dose of estrogen, and the presence or absence of prothrombotic mutations METHODS: In a nationwide, population-based, case-control study, we identified and enrolled 248 women 18 through 49 years of age who had had a first myocardial infarction between 1990 and 1995 and 925 control women who had not had a myocardial infarction and who were matched for age, calendar year of the index event, and area of residence. Subjects supplied information on oral-contraceptive use and major cardiovascular risk factors. An analysis for factor V Leiden and the G20210A mutation in the prothrombin gene was conducted in 217 patients and 763 controls RESULTS: The odds ratio for myocardial infarction among women who used any type of combined oral contraceptive, as compared with nonusers, was 2.0 (95 percent confidence interval, 1.5 to 2.8). The adjusted odds ratio was 2.5 (95 percent confidence interval, 1.5 to 4.1) among women who used second-generation oral contraceptives and 1.3 (95 percent confidence interval, 0.7 to 2.5) among those who used third-generation oral contraceptives. Among women who used oral contraceptives, the odds ratio was 2.1 (95 percent confidence interval, 1.5 to 3.0) for those without a prothrombotic mutation and 1.9 (95 percent confidence interval, 0.6 to 5.5) for those with a mutation CONCLUSIONS: The risk of myocardial infarction was increased among women who used second-generation oral contraceptives. The results with respect to the use of third-generation oral contraceptives were inconclusive but suggested that the risk was lower than the risk associated with second-generation oral contraceptives. The risk of myocardial infarction was similar among women who used oral contraceptives whether or not they had a prothrombotic mutation.

Adolescent↗
PubMed2000

[Roaming through methodology. XVIII. Selection of control groups].

The selection of a valid control group is important in case control studies and has therefore generated a fair amount of discussion in the epidemiologic literature. The proposal of the study usually determines the type of control group that should be selected. It is possible to select population controls, hospital controls, friends or relatives of patients or a variant of these. Each method has specific advantages and disadvantages. Random-digit dialing can be used to select population controls by telephone. This method is a valuable alternative when no registry exists.

Case-Control Studies↗
PubMed1996

Effect of thyroid substitution on hypercholesterolaemia in patients with subclinical hypothyroidism: a reanalysis of intervention studies.

OBJECTIVE: The significance of mild hypercholesterolaemia in subclinical hypothyroidism and whether there is beneficial reduction after thyroxine replacement, remain controversial. We aimed to describe the association between hypercholesterolaemia and subclinical hypothyroidism, and to quantify the effect of thyroid substitution therapy by an analysis of previously published intervention studies. DATA SOURCES: Intervention studies cited in the Medline database from January 1976 until January 1995, with index terms cholesterol, hypercholesterolaemia, hyperlipidaemia, thyrotrophin (TSH), hypothyroidism, thyroid and human. A total of 148 studies were reviewed. DATA EXTRACTION: We recorded the year of publication, study design, number of patients enrolled, mean age, duration of thyroid substitution, normal range of TSH levels, TSH levels pre and post-substitution treatment and total cholesterol in plasma before and after treatment. DATA ANALYSIS: (1) Qualitative description of studies on the relationship between hypercholesterolaemia and hypothyroidism, both subclinical and clinical. (2) Precision weighted pooled estimates of the effect of thyroid substitution therapy on the plasma levels of total cholesterol, in patients with subclinical and overt hypothyroidism. RESULTS: Subclinical hypothyroidism was two to three times more frequent in people with an elevated total plasma cholesterol. In addition, the total plasma cholesterol levels were slightly elevated in patients with subclinical dysfunction of the thyroid. Thyroid substitution therapy in patients with subclinical hypothyroidism, restoring the TSH levels to normal, decreased total cholesterol by 0.4 mmol/l (95% confidence interval (Cl) 0.2-0.6 mmol/l) independently of the initial plasma level. The effect of thyroid substitution therapy on HDL-cholesterol in patients with subclinical hypothyroidism was not consistent. The effect of thyroid substitution in patients with overt hypothyroidism was highly dependent on the pretreatment levels of total cholesterol. In these patients substitution therapy decreased total cholesterol by 1.2 mmol/l (95% Cl 0.9-1.5 mmol/l) when the plasma levels were elevated up to 8 mmol/l, and by 3.4 mmol/l (95% Cl 3.0-3.7) when plasma levels were higher than 8 mmol/l. The high density lipoprotein (HDL)-cholesterol level decreased and amounted to 0.16 mmol/l (95% Cl 0.07-0.24). CONCLUSIONS: Thyroid substitution treatment in patients with hypercholesterolaemia and subclinical hypothyroidism decreases total plasma cholesterol by 0.4 mmol/l, but plasma levels remain elevated in most patients. Further treatment with dietary restriction and cholesterol synthesis inhibitors should then be considered.

Adult↗
PubMed1995

Aspergillus peritonitis in peritoneal dialysis: case report and a review of the literature.

Aspergillus peritonitis is a rare complication of continuous ambulatory peritoneal dialysis. The case is described of a 68-year-old man in whom Aspergillus fumigatus was isolated from the peritoneal dialysate after recurrent peritonitis with Gram-negative rods in association with diverticulosis. Treatment consisting of removal of the catheter and intravenous administration of amphotericin B followed by oral itraconazole was successful. A review of the sparse literature (12 cases) displays uncertainties regarding diagnostic awareness, culture diagnosis, and therapeutic management. Next to institution of appropriate antifungal therapy, early removal of the peritoneal dialysis catheter is recommended, as delayed removal of the catheter appears to be associated with increased mortality and morbidity.

Administration, Oral↗
PubMed1992

Multicenter phase II study of spiroplatin.

Spiroplatin was investigated in a multicenter phase II study, during which the drug was given over 4 h. 64 Patients with nine different solid tumors received 141 cycles of spiroplatin at a dose of 30 mg/m2 every 3 weeks. Most important side effects included nausea, vomiting, myelosuppression, and renal toxicity. Four of 11 evaluable patients with prior cisplatin developed increases in serum creatinine (3 transient, 1 died of renal failure). Of 51 patients without prior cisplatin 2 had a transient increase in serum creatinine levels, and 2 showed persistent changes, in 1 of them leading to hemodialysis. Pre- and posthydration did not reduce drug-induced nephrotoxicity. Only 3 patients showed a response; 1 with renal cell carcinoma, 1 with ovarian carcinoma, and 1 with malignant melanoma. Based on the absence of striking antitumor activity and on the presence of severe unpredictable renal toxicity, the study was stopped prematurely.

Antineoplastic Agents↗
PubMed1991

Phase I study of spiroplatin.

Spiroplatin was investigated in a multicentre phase I study. 67 patients with advanced solid tumours received 151 cycles either by short-term or prolonged infusion, repeated every 3 weeks, at 2.5-40 mg/m2. Myelosuppression and renal toxicity were dose-limiting. Proteinuria, which was dose- and schedule-dependent, indicated glomerular and tubular damage. The maximum tolerated doses (MTD) for poor-risk and good-risk patients were 35 and 40 mg/m2, respectively. The area under the curve (AUC) at the MTD did not correspond with the AUC at the LD10 in mice with ratios of 0.3 for free platinum and 2.6 for total platinum; these were not suitable for predicting the MTD. 1 complete response was observed in a patient with breast cancer and lung metastases and 1 partial response in a patient with adenocarcinoma of the lung. The recommended dose for phase II studies was 30 mg/m2 by 4 h infusion every 3 weeks.

Adult↗