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Biomedical subjects

J Nauta

Publications and source records attributed to J Nauta.

At least 37 records · Page 2Linked to original sources
PubMed1996

Four cases of hemolytic uremic syndrome--source contaminated swimming water?

In June '93, 4 children, aged 1.5-3.5 years, all living in one town, were admitted to our hospital with the diagnosis hemolytic uremic syndrome (HUS) within one week. In cooperation with the local health authorities a common source was searched for. Questionnaires indicated that the single condition shared by all patients was swimming water. The patients were not acquainted, visited different daycares, and had no food resources in common. All 4 patients bathed in the same, shallow, recreational lake within a period of 5 days. During this time the air temperature was high according to Dutch standards (around 27 degrees C), and many people visited the lake, estimated several hundreds a day. The water level was lower than normal. Diarrhea followed 3-11 days after swimming and the first clinical symptoms of HUS developed 6-7 days after the onset of diarrhea. The lake was closed for swimming when the fourth HUS patient was diagnosed and the possibility of transmission by way of the lake was mentioned. E. coli O157: H7 was demonstrated in the fecal samples of 2 index patients. The samples were taken 9-20 days after the start of diarrhea. Antibodies to O157 and verotoxin 2 were strongly positive in all patients. A local outbreak of diarrheal illness was not registered. Of 16 family members who also swam in the same lake, 7 developed symptoms of enteritis, 3 had positive cultures of their fecal samples and 5 had positive serology. Pulsed-field gel electrophoresis of the E. coli isolates of the patients and family members showed an identical pattern. No O157: H7-DNA could be detected in filter concentrated lake water samples using polymerase chain reaction (PCR) enhancement. These samples were, however, taken 16 days after the latest possible date of contamination of our patients, 15 days after decrease of the air temperature to 15-17 degrees C, and 14 days after the inlet from water from the environment. It could thus very well be that the microorganism was no longer present. This third report of swimming water associated HUS should direct environmental surveys in similar cases of local HUS outbreaks.

Antibodies, Bacterial↗
PubMed1995

Renal transplantation and osteoporosis.

A cross sectional study assessed the bone mineral density (BMD) of 20 young adult patients who received a renal transplantation in childhood. The BMD of the lumbar spine, mainly trabecular bone, and of the total body, mainly cortical bone, were measured and expressed as an SD score. Fourteen patients (70%) had a BMD SD score of the lumbar spine below -1, of whom six patients were below -2. Fifteen patients (75%) had a BMD SD score of the total body below -1, of whom seven patients were below -2, Both trabecular and cortical bone appeared to be involved in the osteopenic process. The cumulative dose of prednisone was inversely correlated to both lumbar spine and total body BMD SD score. In a multiple regression analysis the cumulative dose of prednisone appeared to be the only factor with a significant effect on BMD SD score. Most young adult patients who had received a renal transplantation in childhood had moderate to severe osteopenia. Corticosteroid treatment played a major part in the development of osteopenia in these patients.

Adult↗
PubMed1995

Biliary epithelial cells from mice with congenital polycystic kidney disease are hyperresponsive to epidermal growth factor.

Epithelial hyperplasia is an early feature of the renal and biliary lesions in autosomal recessive polycystic kidney disease (ARPKD). To explore the cellular basis of this hyperplasia we isolated, cultured, and characterized biliary tract epithelium from common bile duct explants of mice with ARPKD (the BPK mouse) and controls. Primary cultures resulted in dense colonies of contact-inhibited epithelial cells with a homogenous growth pattern. Colony growth in serum-free basal medium (BM) of BPK-derived cells was not different from controls. Supplementation of BM with epidermal growth factor (EGF) induced a proliferative response in BPK-derived cells that was significantly increased over controls as assessed by [3H]thymidine uptake and expressed as percent change over growth in BM (BPK 239% and controls 131% of BM growth). In contrast, no differences between BPK- and control-derived cells were found with regard to the effects of BM supplementation with IGF-I, IGF-II, acidic fibroblast growth factor, keratinocyte growth factor, hepatocyte growth factor, or transforming growth factor-beta. Primary culture of biliary epithelium may provide a useful in vitro model for the study of the cellular pathophysiology of ARPKD. Our data demonstrate that increased epithelial sensitivity to EGF-like proteins may play a role in biliary epithelial proliferative changes which parallel renal tubular epithelial proliferation in ARPKD.

Animals↗
PubMed1995

Additional weight-bearing during exercise is more important than duration of exercise for anabolic stimulus of bone: a study of running exercise in female rats.

Mechanical loading is necessary for maintenance of skeletal integrity, but the most effective type, intensity, and duration of exercise are not known. In vivo experiments have indicated that the strain generated by the stimulus is more important than the duration of the stimulus. To elucidate this question, we studied 5-month-old female Wistar rats exercised on a motor-driven exercise belt for 17 weeks, 5 days per week (average velocity 20 m/min). Group 1 served as controls, group 2 was trained for 30 min, group 3 was trained for 30 min with a 50-g backpack, and group 4 was trained for 15 min with a 50-g backpack. Total body bone mineral content (BMC), bone mass of the lower extremities (LEBMC), total body lean soft-tissue mass (LSTM), and total body fat-tissue mass (FTM) were measured by dual-energy absorptiometry (DXA) at 0, 6, and 17 weeks. The BMC increased more in group 4 than in controls (15% vs. 8%, p < 0.03). In the other two intervention groups, no significant increases of total body BMC occurred compared with controls, although a trend was observed (12%). The LEBMC increased significantly in all exercising groups after 17 weeks, being 16% in group 2, 15% in group 3, and 20% in group 4, compared with 6% in controls (p < 0.05). The increase in LSTM after 6 weeks was most pronounced in group 3, at 20%, compared with 10% in the control group (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1994

The incidence of hip fractures in independent and institutionalized elderly people.

The incidence density of hip fractures in the population of Amsterdam, aged 70 years and over, was studied according to the type of residence. In 1989, 655 patients were admitted to nine hospitals within Amsterdam for a hip fracture. Postal codes were used to classify the residence of the population and the hip fracture cases as independent, home for the elderly or nursing home. Stepwise logistic regression was used for data analysis. The risk of hip fracture increased with age and was 1.7 times higher for women than for men. In the age group 70-74 years the relative risk (RR) was 7.6 for those in homes for the elderly and 5.8 for those in nursing homes, when compared with the independent elderly. This RR was approximately 1 for those in homes for the elderly aged 85 years and over. However, in nursing homes the RR was still 2.8 in the age group 95+. We concluded that, despite protective measures against falls, the institutionalized elderly are at greater risk of hip fracture than the independent elderly of the same age and sex. This higher risk is especially apparent in the 'younger' age groups.

Age Factors↗
PubMed1994

Serum testosterone level is the major determinant of the male-female differences in serum levels of high-density lipoprotein (HDL) cholesterol and HDL2 cholesterol.

We studied prospectively the effect of exogenous testosterone (testosterone undecanoate [TU] 160 mg/d orally) on lipoprotein profiles in eight hypogonadal males and 10 females (female-to-male transsexuals). Testosterone administration to androgen-deficient men and to eugonadal women produced similar serum levels of testosterone (7.67 +/- 5.47 nmol/L v 8.45 +/- 3.81 nmol/L) and 5 alpha-dihydrotestosterone (DHT) (3.27 +/- 3.52 nmol/L v 3.97 +/- 2.35 nmol/L) in the two groups, while serum estradiol levels were three to four times higher in the females (90 +/- 24 pmol/Lv 376 +/- 315 pmol/L). After testosterone treatment serum high-density lipoprotein (HDL) cholesterol levels decreased from 1.41 +/- 0.27 mmol/L to 1.27 +/- 0.22 mmol/L after 3 months and 1.17 +/- 0.23 mmol/L after 6 months (P < .01) in female-to-male transsexuals and from 1.31 +/- 0.39 mmol/L to 1.09 +/- 0.31 mmol/L after 3 months and 1.10 +/- 0.32 mmol/L (P < .05) after 6 months in hypogonadal males. In particular, serum HDL2 cholesterol levels decreased from 0.71 +/- 0.44 mmol/L to 0.45 +/- 0.20 mmol/L after 3 months and 0.49 +/- 0.39 mmol/L after 6 months (P < .01) in female-to-male transsexuals and from 0.52 +/- 0.12 mmol/L to 0.38 +/- 0.18 mmol/L after 3 months and 0.34 +/- 0.19 mmol/L after 6 months (P < .05) in hypogonadal males. Serum apolipoprotein (apo) A1 levels decreased concomitantly. In both sexes, serum levels of HDL cholesterol and HDL2 cholesterol decreased by approximately 15% and 35%, respectively, whereas serum levels of total cholesterol, triglycerides, low-density lipoprotein (LDL) cholesterol, apo A2, and apo B were not affected.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Loss of bone in the proximal part of the femur following unstable fractures of the leg.

We evaluated the subsequent loss of bone from the proximal part of the ipsilateral and contralateral femora and from the lumbar spine of seven men and nine women who had a fracture of the tibia. The average age was sixty years. All of the fractures were unstable, and the involved leg bore no weight for an average of eight weeks. The bone mineral density was measured with dual-energy x-ray absorptiometry of the lumbar spine and of the femoral neck and the trochanteric region of both hips immediately after the fracture, after the period of immobilization, and at approximately three, six, and twelve months after the fracture. During the period of immobilization, the bone mineral density of the trochanteric region decreased an average of 9 +/- 7 per cent on the side of the fracture, compared with the value immediately after the fracture, but there was no change on the contralateral side (p < 0.01). At twelve months, the average decrease in the trochanteric area was 15 +/- 10 per cent on the side of the fracture, compared with the value immediately after the fracture, but again there had been no change on the uninjured side (p < 0.01). The bone mineral density of the femoral neck on the side of the fracture had decreased 6 +/- 6 per cent at twelve months, compared with a decrease of 2 +/- 4 per cent on the uninjured side (p < 0.05). The bone mineral density of the lumbar spine decreased only during the period of unloading of the fractured leg (1 +/- 2 per cent, p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1993

Intranasal calcitonin suppresses increased bone resorption during short-term immobilization: a double-blind study of the effects of intranasal calcitonin on biochemical parameters of bone turnover.

Immobilization is associated with increased bone resorption and decreased bone formation. We evaluated in a double-blind trial the effect of intranasal administration of salmon calcitonin on biochemical parameters of bone turnover in 32 patients immobilized for a prolapsed intervertebral disk. Calcitonin in a dose of two times 200 IU/day partially inhibited the increase in the fasting 2 h urinary hydroxyproline/creatinine ratio (OHPr/Cr) and calcium/creatinine ratio (Ca/Cr). The increase in OHPr/Cr was 40% less in the calcitonin group compared to the placebo group (P = 0.01), and the increase in Ca/Cr was 80% less in the calcitonin group (P = 0.04). Calcitonin also partially inhibited the increase in serum cross-linked carboxyl-terminal telopeptide of collagen type I (P < 0.05). The decrease in serum 1,25-dihydroxyvitamin D after 10 days of immobilization was significantly less in the calcitonin-treated group than in the placebo group (14 versus 29%, respectively; P < 0.05). Intranasal calcitonin did not influence the pain scores as measured with a visual analog scale (VAS). The tolerability of the nasal calcitonin preparation was excellent. We conclude that nasal salmon calcitonin counteracts the early increase in bone resorption induced by immobilization.

Administration, Intranasal↗
PubMed1993

Renal and biliary abnormalities in a new murine model of autosomal recessive polycystic kidney disease.

Current models of autosomal recessive polycystic kidney disease (ARPKD) fail to demonstrate biliary abnormalities in association with renal cysts. We therefore studied a new murine model of ARPKD in which dual renal tubular and biliary epithelial abnormalities are present. Affected homozygous animals typically die 1 month postnatally in renal failure with progressively enlarged kidneys. Renal cysts shift in site from inner cortical proximal tubules at birth to collecting tubules 20 days later, as determined by segment-specific lectin binding. Increased numbers of mitosis were demonstrated in proximal and collecting tubular cysts. In addition, epithelial hyperplasia was demonstrated morphometrically in the intra- and extrahepatic biliary tract of affected animals. The number of intrahepatic biliary epithelial cells was increased by 50% on postnatal day 5 and by 100% on postnatal day 25 (P < 0.01). Despite an increased frequency of "chaotic" portal areas in mice with renal cysts, no intrahepatic cysts or shape abnormalities of the biliary lumen were detected using biliary casts and morphometry. Additionally there was nonobstructive hyperplastic dilatation of the extrahepatic biliary tract which was linked in all animals to the presence of renal cysts. The hyperplastic abnormalities in both renal and biliary epithelium make this new mouse strain a good model for the study of the dual organ cellular pathophysiology of ARPKD.

Animals↗
PubMed1993

Assessment of pupillary responses to light with IRIS.

With a newly developed method, IRIS, the potential usefulness of various parameters of pupillary reflexes for the assessment of autonomic nerve function was studied. Constriction latency decreased and dilatation latency increased significantly with higher intensities of light (P < 0.01 and P < 0.05, respectively). Thirteen subjects were tested twice one year apart in order to examine long-term intra-individual variability; no significant differences (all P > 0.3) were found. Reproducibility and reliability of hippus and pupil cycle time were lower than for the determination of constriction and dilatation latency. None of the parameters was correlated with age (all P > 0.3). We conclude that pupillary constriction and dilatation latency, assessed with IRIS, are the main dynamical parameters for the study of parasympathetic and sympathetic parts of the autonomic nervous system, that controls the pupillary system. Although a statical parameter, useful additional information may be obtained from the dark adapted pupil diameter. Hippus cycle time and pupil cycle time do not provide additional information and therefore cannot be recommended as standard tests for autonomic nerve function.

Adult↗
PubMed1993

Results of renal transplantation in boys treated for posterior urethral valves.

The results of renal transplantation in boys treated for posterior urethral valves were evaluated and compared with a matched control group. Patient and graft survival was equal in both groups, although serum creatinine levels were slightly higher in the posterior urethral valves group. Postoperative complications, such as urinary tract infections, occurred more frequently in the posterior urethral valves group. Urodynamic evaluation was performed before transplantation in 11 of 20 patients. Adequate treatment of bladder dysfunction, such as poor compliance and/or hyperreflexia, is essential in diminishing the risks of secondary graft damage due to severe bladder dysfunction.

Child↗
PubMed1993

Protein restriction in chronic renal failure.

The aim of the study was to investigate the effect of a protein restricted diet on renal function and growth of children with chronic renal failure. In a multicentre prospective study 56 children (aged 2-18 years) with chronic renal failure were randomly assigned to the protein restricted (0.8-1.1 g/kg/day) or the control group. All children were followed up by the same paediatrician and dietitian. After a follow up period of three years there was no significant difference in glomerular filtration rate between children on a protein restricted diet and children of the control group. There was no significant difference in weight with respect to height and height SD score between the protein restricted and the control group. Compliance with the protein restricted diet, as indicated by the prospective diet diaries and the serum urea:creatinine ratio, was good. This study shows that children with chronic renal failure do not benefit from a protein restricted diet.

Adolescent↗
PubMed1993

A new murine model of autosomal recessive polycystic kidney disease.

We describe the renal cystic disease occurring in a new inbred strain of mice which developed as a spontaneous mutation in otherwise healthy Balb/c mice. The disease displays characteristics of an autosomal recessive polycystic kidney disease. Affected animals develop massive cystic enlargement of the kidneys and die of renal failure at the age of 4 weeks. During postnatal development, there is a gradual shift in site of the lesions. At birth, cystic dilations are localized almost exclusively in proximal tubular segments, whereas in the terminal stages of the disease, 80% of the cysts are localized in collecting tubular segments as defined by segment specific lectin binding. The composition of the basement membrane of the cystic tubular walls during postnatal development as analyzed by immunocytochemistry is essentially normal during the earliest stage of cyst formation. However, with disease progression, the cystic tubular basement membrane demonstrates a decreased immunoreactivity to anti-laminin and anti-entactin antibodies. This indicates a shift in cyst localization during disease progression in this model, and suggests that basement membrane abnormalities are not a primary feature of the early cyst formation and progressive enlargement.

Animals↗
PubMed1992

Protein intake can not be estimated from urinary urea excretion.

We assessed the relationship between protein intake (calculated from a 3-day prospective dietary diary) and 24-h urinary urea excretion in 37 children with chronic renal failure. Protein intake was not restricted during the investigation period. The 24-h urinary urea excretion correlated poorly with the protein intake estimated from the dietary diary (r = 0.58). We conclude that although it is common practice to assess compliance with a protein-restricted diet in children with chronic renal failure with a dietary diary and 24-h urinary urea excretion, the value of this assessment is questionable.

Adolescent↗
PubMed1992

White matter lesions on magnetic resonance imaging in clinically diagnosed Alzheimer's disease. Evidence for heterogeneity.

In a prospective magnetic resonance imaging (MRI) study we evaluated the prevalence and severity of white matter changes in 29 patients with Alzheimer's Disease (AD) and 24 age-matched healthy elderly, all without cerebrovascular risk factors. The AD patients were divided into two groups according to age at onset of symptoms, one with presenile onset AD (n = 13) and one with senile onset AD (n = 16), who were matched for dementia severity. Signal hyperintensities were rated using a semiquantitative scoring method, separately in the periventricular region (PVH) and in the lobar white matter (WMH), as well as in the basal ganglia (BGH) and in the infratentorial region (ITFH). Cortical atrophy as a parameter of grey matter involvement was rated on a 0 (absent) to 3 (severe) scale. We found PVH, WMH and BGH scores to be significantly higher in senile onset AD patients than in age-matched controls. By means of multiple linear logistic regression we found that PVH, WMH and BGH scores were significantly dependent on the diagnosis of senile onset AD, while the PVH score also showed a significant age dependency. Cortical atrophy did not differ significantly between presenile onset AD and senile onset AD patients. These results indicate that presenile onset AD and senile onset AD patients differ with respect to white matter involvement, but not with respect to grey matter involvement on MRI. Since cerebrovascular risk factors were excluded these findings may indicate that senile onset AD patients display more small vessel involvement (arteriolosclerosis) than presenile onset AD patients, suggesting additional (microvascular) factors for the dementia syndrome in senile onset AD. Our data lend support to the growing body of evidence that AD is heterogeneous, consisting of at least two types. Based on our findings two forms can be distinguished: (i) a 'pure' form of the disease, usually with early disease onset, and no more white matter changes than normal for age; (ii) a 'mixed' form, usually with disease onset later in life, and showing more white matter changes on MRI than normal for age.

Aged↗
PubMed1992

Interleukin-2 induces activation of coagulation and fibrinolysis: resemblance to the changes seen during experimental endotoxaemia.

The administration of Interleukin-2 (IL-2) causes the release or generation of other cytokines such as tumour necrosis factor (TNF) which, by disturbing the anticoagulant properties of the endothelium, may induce a procoagulant state in patients receiving this drug. We therefore evaluated the effects of IL-2 on coagulation and fibrinolysis in 14 patients receiving 12 or 18 x 10(6) IU/m2/d of IL-2 given as a 15 min infusion for 5 d. Blood samples were drawn at short intervals after the first IL-2 infusion. The parameters were analysed by way of analysis for repeated measures (F tests rather than t tests). During the first day, thrombin-antithrombin (TAT) complexes started to increase 2 h after the IL-2 infusion, reaching peak levels at 4 h (n = 14; 11.2 +/- 6.4 micrograms/l v 49.8 +/- 49.2 micrograms/l, P < 0.01). Plasma alpha 2 antiplasmin (PAP) complexes showed a similar pattern rising from a mean baseline value of 17.5 +/- 7.6 nmol/l to 66.8 +/- 47.7 nmol at 4 h (P < 0.01). In four patients the peak of PAP preceeded that of TAT. Tissue plasminogen activator (tPA) rose from a mean baseline value of 4.9 +/- 3.7 micrograms/l to 26.3 +/- 13.5 micrograms/l at 4 h (P < 0.01). Plasminogen-activator-inhibitor-1 (PAI-1) levels increased from 59 +/- 35 micrograms/l to 113 +/- 39 micrograms/l at 6 h (P < 0.01). tPA PAI-1 complexes increased from 0.15 +/- 0.07 to 0.69 +/- 0.21 nmol/l at 6 h (P < 0.01). Our study indicates that IL-2 activates the coagulation and fibrinolytic systems in vivo. The changes resemble the perturbations observed after endotoxin/TNF administration. These abnormalities may play a role in the side-effects induced by IL-2 therapy.

Adult↗
PubMed1992

Protein restriction affects fat intake and serum lipids in children with chronic renal failure.

Cardiovascular complications in patients with chronic renal failure have been associated with the hyperlipidemia present in many of these patients. Since a protein-restricted diet is often prescribed in an attempt to preserve renal function, we performed a randomized controlled study in children with chronic renal failure on the effect of a protein-restricted diet on fat intake and serum lipid profiles. Although total fat intake did not change, we found a lower cholesterol intake and a higher polyunsaturated/saturated fat ratio in the patients with the protein-restricted diet. This is probably caused by the restriction of animal protein which results in the replacement of animal fat by vegetable fat in the protein-restricted group. Moreover, we observed an increase of plasma cholesterol and low-density lipoprotein cholesterol in patients with a normal protein intake which was absent in the protein-restricted group. This suggests a favourable effect of the institution of a protein-restricted diet on lipid intake and plasma profile.

Adolescent↗