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Biomedical subjects

E Dekker

Publications and source records attributed to E Dekker.

At least 19 recordsLinked to original sources
PubMed2006

[Screening the population for colorectal cancer: the background to a number of pilot studies in the Netherlands].

Colorectal cancer is one of the most common cancers in the Netherlands, where it is now the second most commonly-occurring cancer in terms of both incidence (10,000 new cases each year) and mortality rate (4,400 each year). - In 40% of all cases the disease is diagnosed at a late stage, which is associated with a poor outcome. - Research has shown that screening of the general population for colorectal cancer by means of the faecal occult blood test (FOBT) results in a reduction in mortality of approximately 16%. Whether endoscopic screening will result in a greater reduction in the mortality rate is currently under investigation. - This year, the first pilot study on implementation of screening for colorectal cancer using two different types of FOBT will start in the Netherlands.

Colorectal Neoplasms↗
PubMed2005

Removal of epileptogenic sequences from video material: the role of color.

BACKGROUND: After Pokémon viewing triggered an epidemic of seizures in Japan, many efforts have been made to design safety guidelines and systems to protect subjects with photosensitivity. The authors developed a new method based upon nonlinear diffusion techniques capable of filtering the epileptogenic content of a video sequence related to color without altering its spatial and luminance content. METHODS: The authors showed to 25 photosensitive patients (18 women, mean age: 22 years) the original Pokémon sequence and a modified one in an ABBA protocol using two television (TV) sets (100 and 50 Hz). RESULTS: Twenty-three patients had a photoparoxysmal response (PPR) according to Waltz classification with at least one of the scenes. The modified sequence triggered fewer and less severe PPRs than the original version in both TVs (p < 0.001). Original sequences elicited generalized PPRs in 56.5% of the trials for the 50 Hz TV and in 41.3% for the 100 Hz TV, whereas modified sequences elicited these responses in only 8.7% (50 Hz) and 4.3% (100 Hz TV) of the trials (p < 0.001). Sensitivity to the modified version on the 50 Hz TV correlated with pattern sensitivity (p < 0.05). CONCLUSION: Specific manipulations of the color modulation-depth could be enough to decrease dramatically the risk of triggering seizures in susceptible subjects exposed to provocative visual scenes. This new method can be implemented in protective devices able to filter out the epileptogenic video sequences in which color plays a fundamental role while leaving intact the spatial content, frequency, and average luminance.

Adolescent↗
PubMed2002

[Prolonged diarrhea and weight loss after a biking trip from Tibet to Nepal: infection with Cyclospora].

A 39-year-old man, who had made a cycling tour from Tibet to Nepal, visited the outpatients' clinic one month later because of prolonged diarrhoea, abdominal complaints and serious weight loss. Parasitological examination of the stool revealed oocysts of Cyclospora cayetanensis and the patient was treated with trimethoprim-sulfamethoxazole (co-trimoxazole) with good result. C. cayetanensis has only recently been discovered as a protozoal cause of diarrhoea. Infections are primarily reported from areas with a low hygienic standard e.g. Central and South America, the Indian subcontinent (Nepal), Indonesia and South-East Asia. Clinical symptoms of infection are diarrhoea (usually watery), abdominal cramps and discomfort. The infection can have a prolonged course. Diagnosis is made by parasitological examination of the stool (one should be cautious not to confuse with cryptosporidia) and treatment with trimethoprim-sulfamethoxazole is effective.

Adult↗
PubMed2002

[Television, children and epilepsy].

Two girls and one boy suffered seizures caused by television and other visual stimuli from 11, 12 and 12 years of age onwards, respectively. EEG recording revealed that intermittent photic stimulation (IPS) provoked epileptiform activity. Technological progress (video games, computer, disco, car, train) has considerably increased the risk for visually-induced seizures. A comprehensive clinical history with special attention to the environmental circumstances is important. For correct diagnosis an EEG with standardised IPS is necessary. Treatment consists of avoidance of strong visual stimuli. Patients may need prophylaxis with valproic acid, which should only be withdrawn after clear reduction of the EEG response to IPS. Repeating the EEG after the dosage has been lowered will help avoiding unnecessary recurrence of seizures.

Adolescent↗
PubMed2001

Glucose production and gluconeogenesis in adults with cerebral malaria.

Hypoglycaemia is an important complication in severe malaria, ascribed to an inhibition of gluconeogenesis. However, the only data available suggested that in severe malaria, total glucose production is increased. We measured glucose production and gluconeogenesis after an overnight fast in all seven patients with cerebral malaria (CM) consecutively admitted to Bao Loc General hospital over a 2-year period, and in six healthy sex- and age-matched controls. Glucose production was measured by infusion of [6,6-(2)H(2)]glucose and the contribution of gluconeogenesis by oral ingestion of (2)H(2)O. Compared to controls, plasma glucose concentration was 42% higher in CM patients (p=0.004), and glucose production was doubled (p=0.003). Gluconeogenesis contributed 100% of the total glucose in CM patients but only 58% in controls (p=0.003). The plasma concentrations of the substrates for gluconeogenesis and the glucoregulatory hormones were not different between patients and controls, except for an increase in lactate and cortisol in the patients. Cerebral malaria is associated with increases rather than decreases in plasma glucose, glucose production and gluconeogenesis, and there is no contribution of glycogenolysis to glucose production. Factors other than malaria per se are involved in the pathogenesis of hypoglycaemia associated with CM.

Adult↗
PubMed2000

Small valve area index: its influence on early mortality after mitral valve replacement.

OBJECTIVE: To test the hypothesis that mitral valve prosthesis-patient mismatch increases postoperative mortality. METHODS AND RESULTS: The effect of mitral valve prosthesis-patient mismatch on survival in a cohort of consecutive patients after mitral valve replacement with a mechanical prosthesis was measured, focusing on the lower tail of the normal distribution curve of the prosthetic valve area index. For the calculation of the geometric valve area index (cm(2)/m(2) body surface area), we used specifications for the geometric valve area supplied by the manufacturer. The cut-off value of the 10th percentile of the valve area index was 1.919 cm(2)/m(2). The study population consisted of 428 adult patients who underwent mitral valve replacement by a Medtronic Hall (n=270, 63%) or a St. Jude Medical prosthesis (n=158, 37%). The size of the valves implanted ranged from 25 mm to 31 mm. The valve area index showed a normal distribution curve ranging from 1.43 to 2.98 cm(2)/m(2) with a mean of 2.2 cm(2)/m(2). Group 1 (n=33) had a valve area index <1.9 cm(2)/m(2) and group 2 (n=395), > or =1.9 cm(2)/m(2). The 30-day mortality was higher in group 1 than in group 2 (18.2 vs. 4.1%, P=0.005). Multivariate logistic regression analysis of the determinants of the 30-day mortality rendered a small valve area index (<1.9 cm(2)/m(2)) as an independent risk indicator: relative risk 4.3 (95% CI 1.6-9.5; P=0. 0043). The difference in overall survival between the two groups was entirely due to the high 30-day mortality in the patients with small valve area indices, congestive heart failure being the main cause of death. CONCLUSIONS: By concentrating on the extreme lower tail of the normal distribution of the valve area index, a strong and independent relation was found between relatively small valves (valve area index <1.9 cm(2)/m(2)) and 30-day mortality. We found no influence of valve size on late mortality beyond the first 30 days.

Adult↗
PubMed1999

Podiatric care for diabetic patients with foot problems: an observational study.

The aims of this study were to describe podiatric care for diabetic patients with foot problems and to explore the changes in knowledge, self-care behaviour and physical functioning after podiatric care. The treatment characteristics of 26 diabetic patients referred to podiatry were assessed. Prior to the first podiatric visit (T1) and 20 weeks later (T2) these patients filled in a structured questionnaire and performed a six-minute walking test. In half the number of patients preventive goals were set and strived for by general education about the diabetic foot and advice on footwear and self-care behaviour. With regard to treatment, reduction of pain was the most frequently selected goal. To achieve this reduction, a variety of interventions was applied. After podiatric care, patients reported having less severe foot pain and some improvements in functional ability and self-care behaviour were found. This study offers clues to start controlled clinical trials on the effectiveness of podiatry for diabetic patients. Trials should not only be directed to (the role of podiatry in) ulcer healing; it may be even more significant to study its effectiveness for the purpose of prevention and treatment of early-stage diabetic foot symptoms.

Activities of Daily Living↗
PubMed1999

To operate or not on elderly patients with aortic stenosis: the decision and its consequences.

OBJECTIVE: To evaluate the application of guidelines in the decision making process leading to medical or surgical treatment for aortic stenosis in elderly patients. DESIGN: Cohort analysis based on a prospective inclusive registry. SETTING: 205 consecutive patients (>/= 70 years) with clinically relevant isolated aortic stenosis and without serious comorbidity, seen for the first time in the Doppler-echocardiographic laboratories of three university hospitals in the Netherlands. RESULTS: The initial choice was surgery in 94 patients and medical treatment in 111. Only 59% of the patients who should have had valve replacement according to the practice guidelines were actually offered surgical treatment. These were mainly symptomatic patients under 80 years of age with a high gradient. Operative mortality (30 days) was only 2%. The three year survival was 80% in the surgical group (17 deaths among 94 patients) and 49% in the medical group (43/111). Multivariate analysis showed that only patients with a high baseline risk, mainly determined by impaired left ventricular function, had a significantly better three year survival with surgical treatment than with medical treatment. CONCLUSIONS: In daily practice, elderly patients with clinically relevant symptomatic aortic stenosis are often denied surgical treatment. This study indicates that a surgical approach, especially where there is impaired systolic left ventricular function, is associated with better survival.

Age Factors↗
PubMed1998

[Quality assessment indicators of cardiac surgeons' work; the validity of mortality rates].

OBJECTIVE: To determine the possibility of comparing the mortality rates of patients operated by different heart surgeons with each other. DESIGN: Retrospective cohort study. SETTING: Academic Medical Centre, Amsterdam, the Netherlands. PATIENTS AND METHODS: Clinical information, operation data and follow-up data on 783 patients who had undergone cardiac valve replacement, were collected from the clinical records. Aortic valve replacement had been performed in 446 patients (1979-1986) and mitral valve replacement in 337 patients (1980-1990). RESULTS: The one-year mortality rate was higher among patients operated on by heart surgeon A than among patients operated on by the other heart surgeons from the same team, viz. 16.4% and 9.5%, respectively, an absolute difference of 6.9%. The 95% confidence interval of the difference was 1.7-12.9. However, it was also found that the risk profiles of these patients of surgeon A differed from those of the other patients. After multivariate correction for this difference in risk profile, the difference in mortality was no longer statistically significant. CONCLUSION: The differences in mortality observed in our study could not be attributed to difference in quality of the heart surgeons, but were related with the risk profiles of the patients operated by one of them. Thorough analysis with correction for risks is necessary for the assessment of the quality of care, if the conclusions are not to be misleading.

Adult↗
PubMed1998

Sharp transients in the sleep EEG of healthy adults: a possible pitfall in the diagnostic assessment of seizure disorders.

The use of sleep EEG recordings is a routine procedure in the diagnostic work up of patients with suspected epilepsy. With respect to the diagnostic significance of paroxysmal EEG phenomena it is of importance to be informed about the incidence of such paroxysms in EEG's of healthy subjects. Several benign paroxysmal EEG phenomena during drowsiness or sleep have been identified (benign epileptiform transients of sleep (BETS), 14 and 6 positive spikes). Recent studies have shown that other, apparently aspecific, paroxysmal sharp transients may be recorded during drowsiness or sleep in healthy subjects. In order to obtain more data on such paroxysmal EEG phenomena during sleep, a qualitative and semi quantitative analysis was performed on full night sleep recordings from 60 carefully selected healthy volunteers. Only 4 recordings were completely without the studied phenomena, all others showed some suspicious paroxysmal transients and some rare yet true specific epileptiform discharges were recorded in 8 subjects (13%), predominantly during transient periods of light non-REM sleep in the first two sleep cycles. The presence of some sharp transients during drowsiness or light sleep thus should be considered as a non-specific and non-pathological finding. Moreover these findings indicate the limited diagnostic specificity of the presence of a few epileptiform discharges during sleep, especially in patients with an ambiguous clinical history of epilepsy.

Adolescent↗
PubMed1998

Light diffusion in photosensitive epilepsy.

Photosensitivity is usually tested by intermittent photic stimulation. Photoparoxysmal responses in the EEG are enhanced when the eyes remain closed during stimulation. We tested the hypothesis that this is due to diffusion of light by the eyelids. In 25 photosensitive patients, conditions 'eye closure', 'eyes closed', 'eyes open' and 'eyes open with diffuser' were tested for frequencies of 2-60 Hz. Additional influences of a red filter and fixation were also examined. The photosensitivity range was maximal in the condition 'eyes open with diffuser', due to an increase of the upper limit to a median 60 Hz (range 25-60), from 35 (15-50) Hz with eyes open, 37.5 (25-60) Hz with eyes closed and 40 (23-60) Hz with eye closure (P = 0.0002). This effect was attenuated in patients on valproic acid and with the use of a red or white filter. Testing with a diffuser was more sensitive than without, except for one patient who was photosensitive only in the eye closure condition. The influence of the eyelids on photosensitivity can be explained by diffusion of light, attentuated by an intensity loss. Use of a diffuser may simplify testing for photosensitivity in the EEG laboratory. The diffusion effect may explain seizure susceptibility in front of 50 and 60 Hz television screens.

Adolescent↗
PubMed1998

Indomethacin stimulates glucose production in adults with uncomplicated falciparum malaria.

In healthy subjects, basal hepatic glucose production is (partly) regulated by paracrine intrahepatic factors. It is unknown if these paracrine factors also influence basal glucose production in infectious diseases with increased glucose production. We compared the effects of 150 mg indomethacin (n = 9), a nonendocrine stimulator of glucose production in healthy adults, and placebo (n = 7) on hepatic glucose production in Vietnamese adults with uncomplicated falciparum malaria. Glucose production was measured by primed, continuous infusion of [6,6-2H2]glucose. After indomethacin, the plasma glucose concentration and glucose production increased in all subjects from 5.3 +/- 0.1 mmol/L to a maximum of 7.1 +/- 0.3 mmol/L (P < .05) and from 17.6 +/- 0.8 micromol x kg(-1) x min(-1) to a maximum of 26.2 +/- 2.5 micromol x kg(-1) x min(-1) (P < .05), respectively. In the control group, the plasma glucose concentration and glucose production declined gradually during 4 hours from 5.4 +/- 0.2 mmol/L to 5.1 +/- 0.1 mmol/L (P < .05) and from 17.1 +/- 0.8 micromol x kg(-1) x min(-1) to 15.1 +/- 1.0 micromol x kg(-1) x min(-1) (P < .05), respectively. There were no differences in plasma concentrations of insulin, counterregulatory hormones, or cytokines between the groups. We conclude that indomethacin administration results in a transient increase in glucose production in patients with uncomplicated falciparum malaria in the absence of changes in plasma concentrations of glucoregulatory hormones or cytokines. Thus, this study indicates that in uncomplicated falciparum malaria, the rate of basal hepatic glucose production is also regulated by paracrine intrahepatic factors.

Adult↗
PubMed1998

Clinical and functional correlates of foot pain in diabetic patients.

PURPOSE: Patients with diabetes mellitus frequently suffer from foot pain. This pain seems to be a neglected area in studies on the diabetic foot. The purpose of this study was to identify clinical variables associated with foot pain in diabetic patients. In addition, the relationships between foot pain and several functional impairments and disabilities were explored. METHOD: The research group consisted of 29 diabetic patients with any symptoms possibly associated with a diabetic foot, who were referred to podiatry. The relationships between several clinical measures and foot pain were analysed by means of Mann-Whitney U-tests. In addition, Spearman rank correlations coefficients were computed to assess the relationships between foot pain and measures of functional health. RESULTS: Diabetic patients suffering from sensory neuropathy experience more severe foot pain. Furthermore, patients with more severe foot pain experience more fatigue, more disabilities in walking and a lower level of affective well-being. CONCLUSION: Based on these findings this paper concludes that foot pain in diabetic patients is an important impairment which deserves further scientific attention.

Adolescent↗
PubMed1997

The influence of alanine infusion on glucose production in 'malnourished' African children with falciparum malaria.

By US standards, about half of African children are malnourished, although most appear clinically normal. It is possible that precursor supply for gluconeogenesis is limited to a greater extent in these seemingly malnourished African children than in healthy children, consequently limiting glucose production. Since in malaria peripheral glucose utilization is increased, precursor supply could play an even more critical role in maintaining glucose production in African children suffering from falciparum malaria. We studied the effect of alanine infusion (1.5 mg/kg/min) on glucose production (measured by infusion of [6,6-2H2]glucose) and plasma glucose concentration in 10 consecutive children with acute, uncomplicated falciparum malaria. By US standards, six children were below the 10th percentile of weight for height and seven were below the 10th percentile of height for age. Plasma concentrations of alanine increased during alanine infusion from 153 +/- 21 to 468 +/- 39 mumol/l, whereas plasma lactate concentrations did not change (1.4 +/- 0.2 vs. 1.3 +/- 0.2 mmol/l). Plasma glucose concentration and glucose production did not change during alanine infusion: 4.6 +/- 0.3 vs. 4.5 +/- 0.3 mmol/l and 5.8 +/- 0.4 vs. 5.7 +/- 0.3 mg/kg/min, respectively. Gluconeogenic precursor supply is sufficient for maintainance of glucose production in African children with uncomplicated malaria who are malnourished by US standards.

Acute Disease↗