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Biomedical subjects

D Willems

Publications and source records attributed to D Willems.

At least 19 recordsLinked to original sources
PubMed2001

Zinc supplementation increases bone alkaline phosphatase in healthy men.

Zinc takes part in the metabolism of bone as a constituent of the matrix and as an activator of several metallo-enzymes. Animal in vitro and in vivo studies strongly suggest that zinc supplementation could stimulate bone formation and inhibit bone resorption but data in humans remain rare. The biological effects of 50 mg zinc given orally as gluconate in 20 healthy male volunteers were investigated in a 12 weeks double-blind placebo-controlled randomized trial. To investigate bone turnover, total alkaline phosphatases activity (ALP), bone specific alkaline phosphatase activity (BAPE) and BAP mass (BAP-M) concentration were measured as parameters of bone formation while urine calcium and C-terminal collagen peptide were determined as parameters of bone resorption. Samples were obtained in fasting subjects at baseline and after 6 and 12 weeks. In zinc treated subjects, a significant increase was observed at least after 12 weeks in total ALP (p < 0.01), BAP-M (p < 0.05) and BAP-E (p < 0.02). These parameters did not significantly change in the placebo group. Urine zinc/creatinine ratio significantly increased after 6 (p < 0.03) and 12 weeks (p < 0.04) in the zinc-treated group and was significantly different from the placebo group (p < 0.002). There was no significant effect of zinc supplementation on parameters of bone resorption. In conclusion, zinc supplementation at supraphysiological doses increased parameters of bone formation in healthy men while parameters of bone resorption remained unchanged.

Adult↗
PubMed2000

Managing one's body using self-management techniques: practicing autonomy.

This paper discusses some of the anthropological and philosophical features of the use of self-management plans by patients with a chronic disease, focusing on patients with asthma. Characteristics of this technologically mediated form of self-care are contrasted with the work of Mauss and Foucault on body techniques and techniques of self. The similarities and differences between self-management of asthma and Foucault's technologies of self highlight some of the ways in which self-management contributes to modifications in the definitions of patients and physicians. Patients, in measuring their lung function, first come to rely on measurements more than on felt disturbances, but next, felt disturbances become modified by previous measurements. Physicians, one the other hand, see their role changed from expert to being a participant in a joint treatment. It is argued that the concept of agency is more appropriate for describing the advantage of self-management for patients than autonomy.

Anti-Asthmatic Agents↗
PubMed2000

TGF-beta autocrine loop regulates cell growth and myogenic differentiation in human rhabdomyosarcoma cells.

Transforming growth factor beta (TGF) is a well-known inhibitor of myogenic differentiation as well as an autocrine product of rhabdomyosarcoma cells. We studied the role of the TGF-beta autocrine loop in regulating growth and myogenic differentiation in the human rhabdomyosarcoma cell line, RD. We previously reported that the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) induces growth arrest and myogenic differentiation in these cells, which constitutively express muscle regulatory factors. We show that TPA inhibits the activation of secreted latent TGF-beta, thus decreasing the concentration of active TGF-beta to which the cells are exposed. This event is mediated by the TPA-induced alteration of the uPA/PAI serine-protease system. Complete removal of TGF-beta, mediated by the ectopic expression of a soluble type II TGF-beta receptor dominant negative cDNA, induces growth arrest, but does not trigger differentiation. In contrast, a reduction in the TGF-beta concentration, to a range of 0.14-0.20 x 10(-2) ng/ml (which is similar to that measured in TPA-treated cells), mimics TPA-induced differentiation. Taken together, these data demonstrate that cell growth and suppression of differentiation in rhabdomyosarcoma cells require overproduction of active TGF-beta; furthermore, they show that a 'critical' concentration of TGF-beta is necessary for myogenic differentiation to occur, whereas myogenesis is abolished below and above this concentration. By impairing the TGF-beta autocrine loop, TPA stabilizes the factor concentration within the range compatible for differentiation to occur. In contrast, in human primary muscle cells a much higher concentration of exogenous TGF-beta is required for the differentiation inhibitory effect and TPA inhibits differentiation in these cells probably through a TGF-beta independent mechanism. These data thus clarify the mechanism underlying the multiple roles of TGF-beta in the regulation of both the transformed and differentiated phenotype.

Animals↗
PubMed1999

Clinical relevance of thiamine status amongst hospitalized elderly patients.

BACKGROUND: The prevalence and the consequences of thiamine deficiency among elderly patients admitted to acute geriatric wards are not known. OBJECTIVES: (1) To assess the prevalence of thiamine deficiency in patients admitted to a geriatric ward compared to age-matched ambulatory outpatients; (2) to identify their diseases and problems associated with thiamine deficiency, and (3) to determine the relationship between the thiamine status and the cognitive and functional status of these patients. MATERIALS AND METHODS: 118 aged hospitalized patients (83 +/- 7 years; mean age +/- SD) were prospectively enrolled on admission to the geriatric ward. Their cognitive status was assessed using the Mini-Mental State Examination (MMSE) and their ability to perform their activities of daily living (ADL) using ADL scales. The effect of exogenous thiamine pyrophosphate (TPP) addition on the blood transketolase (TK) activity (TPP TK effect) served to estimate thiamine deficiency. Socioeconomic data, diseases and treatment were identified as potential associated risk factors. This group of hospitalized patients was divided according to their thiamine status to characterize the conditions associated with thiamine deficiency. Thirty-five outpatients without any functional or cognitive impairment served as a control group. RESULTS: Of 118 inpatients, 46 (39%) presented with a TPP TK effect of >15%, and 6 with values of >22%, indicating moderate and severe thiamine deficiency, respectively. Only 6 of 30 outpatients (20%) exhibited a TPP TK effect of >15% and none of them reached values of >18%. Although it tended to be lower in outpatients, the mean TPP TK effect did not statistically differ from the mean of inpatients. Thiamine-deficient inpatients comprised a larger proportion of institutionalized subjects than nondeficient inpatients (87 versus 47%, p < 0.001). Functional status, cognitive functions and the occurrence of delirium did not differ according to their thiamine status. By contrast, thiamine-deficient inpatients exhibited a higher proportion of Alzheimer's disease, depression, cardiac failure and falls. Furosemide was more frequently taken by thiamine-deficient patients. CONCLUSIONS: Severe thiamine deficiency remained quite low among the hospitalized elderly. The prevalence of moderate thiamine deficiency approached 40%. Institutionalized subjects were at particular risk of developing thiamine deficiency. Its clinical relevance on functional status and on cognitive function remained not significant. By contrast, a high proportion of falls, Alzheimer's disease, depression, cardiac failure and furosemide use could have been related to thiamine deficiency.

Activities of Daily Living↗
PubMed1998

Serum antioxidant status and oxidized LDL in well-controlled young type 1 diabetic patients with and without subclinical complications.

It has been suggested that oxidative stress may play an important role in the pathogenesis of diabetic complications because hyperglycemia may cause increased production of free radicals. However, studies on the antioxidant status of young type 1 diabetic patients are very scarce as well as the relationships of oxidative stress and the presence of subclinical complications. Therefore, it was decided to evaluate autoantibodies against LDL (o-LAB) and antioxidant status in relationship with glycated hemoglobin levels (HbA1c), lipoproteins and subclinical complications (retinopathy, neuropathy and nephropathy). The study included 110 young type 1 diabetic patients, with a median age of 15 years and a median diabetes duration of 5 years. The mean+/-S.E.M. of HbA1c levels was 7.1+/-0.2%. Subclinical complications were detected in 26 patients. Total antioxidant status (TAS), vitamin A or E were not decreased in the patients and no significant differences were noted between the different subgroups of patients classified according to their subclinical complications. HbA1c levels were not related to antioxidants. Autoantibodies against LDL-lipoproteins decreased with age and diabetes duration, as reported in healthy non diabetic subjects. In conclusion, in the diabetic patients with a more or less good diabetic control, increased lipid peroxidation or reduced lipid antioxidant defense could not be demonstrated, even for the patients with subclinical complications.

Adolescent↗
PubMed1997

Lens fibre transdifferentiation in cultured larval Xenopus laevis outer cornea under the influence of neural retina-conditioned medium.

The outer cornea of larval Xenopus laevis can reprogram cell differentiation when cultured in medium conditioned by X. laevis neural retina (XRCM) or by Rana esculenta neural retina (RRCM). Under these experimental conditions corneal cells showed the same series of cytological changes of fibre cell differentiation observed during ontogenesis and in vivo lens regeneration: enlargement of nuclei and nucleoli, increase of ribosomal population (cytoplasm-basophilia), cell elongation gradual loss of basophilic properties and acquisition of acidophilic properties for crystallin synthesis and accumulation. These events were completely dependent on XRCM or RRCM, suggesting that the neural retina secretes a factor(s) which initiates and sustains lens fibre transdifferentiation of the corneal epithelial cells. This culture system appears to be a suitable one for investigating the control of lens fibre transdifferentiation in vitro.

Animals↗
PubMed1997

In vitro lens transdifferentiation of Xenopus laevis outer cornea induced by Fibroblast Growth Factor (FGF).

It has been shown that lens regeneration from outer cornea of larval Xenopus laevis is dependent on neural retina both in vivo and in tissue culture. The isolated outer cornea cultured in the presence of bovine brain-derived acidic Fibroblast Growth Factor (aFGF) is able to reprogram the differentiation into lens fibers, although this transdifferentiative process is not coupled with the formation of a normally organized lens. The capacity of aFGF to promote lens differentiation from cornea is not linked to its mitogenic activity. The cultured corneal cells can transdifferentiate into lens fibers in the presence of aFGF when DNA replication and cell proliferation are prevented by addition of aphidicolin, a specific inhibitor of DNA polymerase in eukaryotes, to the culture medium.

Animals↗
PubMed1997

Glycated hemoglobin and related factors in diabetic children and adolescents under 18 years of age: a Belgian experience.

OBJECTIVE: To determine, in an unselected population of diabetic children and adolescents < 18 years of age, which HbA1c levels can be achieved, and to examine the relationships with insulin regimen, insulin dose, sex, diabetes duration, BM1, and frequency of home blood glucose monitoring (HBGM) and outpatient clinic attendance. RESEARCH DESIGN AND METHODS: A total of 144 unselected subjects (73 boys and 71 girls) aged 11.8 +/- 3.7 years (mean +/- SD) were included in the study over a 6-month period. They had diabetes durations ranging from 5 months to 15 years (4.0 +/- 3.0). They were followed by the same pediatric diabetologist and the same nurse. The yearly frequency of visits was 8.9 +/- 2.0, and the monthly frequency of HBGM was 111 +/- 27. Of the patients, 129 were treated with two daily insulin injections of an individualized mixture of rapid- and intermediate-acting insulins, and 15 adolescents were treated with four injections using the basal-bolus regimen. The patients were divided into two subgroups according to diabetes duration: < or = 2 years (n = 53) and > 2 years (n = 91), i.e., outside the honeymoon period. HbA1c was measured by a high-pressure liquid chromatography method (normal values 3.9-5.5%). RESULTS: The mean +/- SD HbA1c level in the 144 children and adolescents was 6.6 +/- 1.2% using our method. In 62% of the patients, it was possible to obtain an HbA1c level under the normal mean value plus 5 SD. HbA1c was not related to sex, number of insulin injections, or age, i.e., it was not poorer at adolescence. The mean daily insulin dose was 0.9 U/kg body wt, being lower during the first 2 years of diabetes and reaching 1 U at adolescence. HbA1c levels were lower during the first 2 years of diabetes (6.2 +/- 1.0%) than afterwards (6.9 +/- 1.2%), but the frequencies of outpatient visits and HBGM were higher. After 2 years, HbA1c was negatively correlated with the frequency of HBGM. The yearly incidence rate of severe hypoglycemic episodes was 0.2. After the age of 13 years, BM1 was significantly higher in girls and in adolescents on four daily injections. CONCLUSIONS: In nearly two-thirds of diabetic children and adolescents, it is possible to obtain HbA1c levels under the normal mean plus 5 SD, which is considered satisfactory and close to that of the adult cohort of the Diabetes Control and Complications Trial (DCCT) with intensive treatment. There is no difference between the children on only two daily insulin injections and the adolescents on four injections. After 2 years of diabetes, increased frequency of HBGM helps reduce HbA1c levels, taking into account the "intensive" education of the patients and their families. Adolescent girls on four injections must pay attention to the risk of becoming overweight.

Adolescent↗
PubMed1997

Comparability of a new turbidimetric digoxin test with other immunochemical tests and with HPLC--a multicenter evaluation.

A new turbidimetric inhibition immunoassay for digoxin (Tina-quant [a] Digoxin, Boehringer Mannheim) was evaluated in seven laboratories. It can be performed without sample pretreatment with ready-to-use reagents on nondedicated analyzers in combination with routine clinical chemistry. The studies revealed a good analytical performance: lower limit of detection 0.12 microg/L (3 SD from mean of blank); linearity up to 7.5 microg/L; median between-run CVs 8.1% (0.6 microg/L), 2.8% (1.5 microg/L), 1.9% (3 microg/L); mean analytical recovery in control sera 98-102%; slopes from 0.97 to 1.09 and intercepts from -0.28 to 0.10 microg/L in comparison with four immunoassays; and a high resistance to common interferents. The test was more resistant to digoxin-like immunoreactive factor (DLIF) interference than other methods, showing cross-reactivity only in some intensive care patient samples. Among 192 patients in whom DLIF is expected (e.g., pregnant women, patients with renal failure, newborns), 90% of results were < or =0.26 microg/L digoxin. Cortisol showed no cross-reactivity and digoxigenin had a low reactivity. An interlaboratory survey revealed a good comparability of the Tina-quant [a] test with the median of all methods (slope 0.99, intercept -0.06 microg/L). An HPLC method for digoxin based on isocratic separation of samples on an RP-18 column followed by detection by an immunoassay yielded a reasonable comparability with the immunochemical tests with noncritical samples. Divergent results of immunoassays caused by DLIFs or different cross-reactivities with digoxin metabolites or derivatives can be explained by the use of this HPLC method.

Anticoagulants↗
PubMed1997

[Glycosylated hemoglobin in nonselected under-18-year-old young diabetics. Comparison of 2 HPLC methods].

The aim of this study is to determine, in an unselected population of diabetic children and adolescents < 18 years of age, which HbA1c levels can be achieved, and to compare 2 different HPLC (High Performance Liquid Chromatography) methods. One hundred and fourty-four unselected subjects (73 boys and 71 girls), with a diabetes duration ranging from 5 months to 15 years were included. HbA1c was measured simultaneously in our hospital and at the Steno Institute in Danemark. The mean (SD) HbA1c levels in the 144 children and adolescents were 6.6 +/- 1.2% using our method (normal values: 3.9-5.5%), and 7.7 +/- 1.1% at the Steno Institute (normal values : 4.4-6.3%), with a mean difference of 1.1 +/- 0.4%. Therefore, one must be cautious when comparing HbA1c levels, even by HPLC, between laboratories. Moreover, the lack of HbA1c standardization makes difficult to define HbA1c thresholds in order to avoid diabetic complications. In more than 60% of the patients, it is possible to obtain an HbA1c level under the normal mean value plus 5 SD. In the other paediatric studies, HbA1c levels are higher, whatever the type of treatment.

Adolescent↗
PubMed1996

The inhibition of differentiation caused by TGFbeta in fetal myoblasts is dependent upon selective expression of PKCtheta: a possible molecular basis for myoblast diversification during limb histogenesis.

Embryonic and fetal skeletal myoblasts are responsible for the formation of primary and secondary fibers in mammals, but the mechanism which diversifies their fate is unknown. In vitro, embryonic myoblasts are resistant to the differentiation inhibitory effects of transforming growth factor beta and phorbol esters. Thus, differential expression of specific molecules involved in the transduction of extracellular signals may contribute to the different phenotypes. We report here that protein kinase C theta, but none of the other known protein kinase C isoforms, is selectively expressed in fetal and postnatal muscle cells (at both the myoblast and myotube stage) in vitro and in vivo. By contrast, embryonic myoblasts and myotubes do not express protein kinase C theta in vitro or in vivo. This difference is causally related to a differential response to transforming growth factor beta, since overexpression of protein kinase C theta, but not of protein kinase C alpha or zeta, in embryonic myoblasts makes these cells sensitive to transforming growth factor beta. These data demonstrate for the first time that a protein kinase C isoform is a key component of the signal transduction cascade which follows exposure of myoblasts to transforming growth factor beta. They also suggest a specific role for protein kinase C theta in determining the fate of different myoblasts during muscle histogenesis.

Amino Acid Sequence↗
PubMed1996

Serum lipoprotein (a) in type 1 diabetic children and adolescents: relationships with HbA1c and subclinical complications.

UNLABELLED: In a population of 106 young type I diabetic patients, we evaluated whether a relationship exists between lipoprotein (Lp)(a) or apolipoproteins and the degree of metabolic control (HbA1c, fructosamine) or the subclinical complications. The patients were subdivided according to puberty and to the presence or not of subclinical complications (no complications [n = 32]; retinopathy at fluorescein angiography [n = 28]; neuropathy diagnosed by reduced peroneal motor nerve conduction velocity [n = 30]; nephropathy determined by presence of micro-albuminuria [n = 15]. Lp(a) concentrations were not significantly increased in the whole group of diabetic patients. There was no difference between girls and boys, nor between the prepubertal children and the others. There were no significant correlations between the markers of metabolic control and Lp(a). Nevertheless, if the diabetic patients were divided into two groups according to the levels of HbA1c (<7.6 or > or = 6% Hb), Lp(a) tends to be higher in the poorly controlled, but not to any significant degree. On the other hand, significant increases of total cholesterol, triglycerides, low density lipoprotein cholesterol and apolipoprotein B levels were observed in poorly controlled patients. Lp(a) concentrations were significantly lower in patients with subclinical neuropathy or nephropathy than in patients without these complications, but not in patients with retinopathy versus no retinopathy. These results are confirmed by categorical analysis (i.e. Lp(a) < or = 30 vs > 30 mg/dl). CONCLUSION: Lp(a) levels are not significantly increased in poorly controlled insulin-dependent diabetes mellitus patients. High controlled insulin-dependent diabetes mellitus patients. High levels of Lp(a), in young diabetic patients, are not markers for subclinical complications (retinopathy, neuropathy and nephropathy). On the contrary, low Lp(a) levels were found in subjects with subclinical neuropathy or nephropathy.

Adolescent↗
PubMed1996

Colonoscopy without premedication versus barium enema: a comparison of patient discomfort.

BACKGROUND: Colonoscopy is considered a painful procedure requiring routine intravenous sedation. We investigated whether unsedated colonoscopy causes more discomfort than barium enema. METHODS: Procedure-related discomfort was determined in 100 consecutive patients undergoing colonoscopy without premedication and in an equal number of patients referred for sigmoidoscopy and barium enema. All patients underwent such examinations for the first time and had no history of previous bowel surgery. During colonoscopy, sedation was offered if significant pain or discomfort occurred. RESULTS: In patients without stenosis and with satisfactory preparation, the completion rate of colonoscopy was 95%. Five percent of all patients undergoing endoscopy required sedation. On an analog scale ranging from 1 to 9, patients undergoing colonoscopy and barium enema reported similar ratings for procedure related discomfort (3.2 +/- 1.7 and 3.1 +/- 1.9) and for discomfort caused by bowel preparation (3.2 +/- 2.1 and 3.1 +/- 1.8). Eighty-seven percent of all patients undergoing colonoscopy stated that they would prefer no premedication in the event of repeated examinations. CONCLUSIONS: Colonoscopy with sedation on demand does not cause more discomfort than barium enema and will be accepted by the vast majority of patients undergoing this procedure.

Barium Sulfate↗
PubMed1996

The case manager in Holland behind the dikes: a hole filler or bridge builder?

The health and social care service system in the Netherlands is fragmented and poorly organized. Facing an increase in the number of elderly citizens, a more consumer-oriented and vocal citizenry, and rising competition at least in part in response to government concerns over runaway costs, Dutch government officials and social researchers have been experimenting with various forms of case management since the mid-1980s. For some types of clients, such as the mentally handicapped, case management seems to be well accepted. Many issues remain to be resolved, however, including (a) the level of clinical expertise needed by case managers for clients with complex medical problems; (b) whether case management tasks are more appropriately carried out by service providers or as a separate function; and (c) how much autonomy service providers will be expected to relinquish under the control of a case manager.

Case Management↗