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Biomedical subjects

J Nauta

Publications and source records attributed to J Nauta.

At least 19 recordsLinked to original sources
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

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↗
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↗
PubMed1991

Biochemical parameters of bone turnover during ten days of bed rest and subsequent mobilization.

Immobilization is associated with increased bone resorption. To investigate the early onset of increased bone resorption, we evaluated 14 patients who were immobilized for 10 days because of lumbar disc protrusion. The fasting urinary hydroxyproline/creatinine ratio increased significantly after four days (P less than 0.01), reached a peak after 10 days (16.4 +/- 3.3 mumol/mmol, 27.6 +/- 8.8 mumol mmol, P less than 0.01) and returned slowly to baseline values after mobilization. The fasting urinary calcium creatinine ratio followed a similar pattern. Serum calcium and phosphate increased during immobilization (P less than 0.01). Serum 1,25-dihydroxyvitamin D decreased significantly during immobilization (98 +/- 33 pmol/l vs. 79 +/- 36 pmol/l, P less than 0.05), and reached a nadir one week after mobilization (P less than 0.01). We conclude that there is an early significant increment in resorption parameters, with a slow return during the mobilization period. Serum 1,25-dihydroxyvitamin D is suppressed as a result of the increased serum calcium and serum phosphate levels.

Adult↗
PubMed1991

Forced hydration prior to renography in children with hydronephrosis. An evaluation.

We have developed a method of diuretic renography for the assessment of upper urinary tract obstruction in children. A maximal diuresis under standardised conditions is obtained by forced intravenous hydration over a 2-h period prior to renography. We evaluated the predictive value of this method for the clinical and functional outcome in 73 children with apparent unilateral pelviureteric junction obstruction. The predictive value of a non-obstructive pattern was 94%, while the predictive value of an obstructive pattern could not be assessed accurately because the patients concerned subsequently underwent operation. The method is safe and reliable and offers advantages over conventional diuretic renography.

Adolescent↗
PubMed1991

Cyclandelate in diabetic neuropathy. A double-blind, placebo-controlled, randomized, cross-over study.

Cyclandelate has the ability to improve the rheological properties of the blood and therefore may improve blood supply of peripheral nerves. Previous studies in diabetic neuropathy have shown beneficial effects of the drug. We performed a double-blind, placebo-controlled, cross-over study in 40 diabetic patients with cyclandelate in a dose of 1600 mg daily. Motor and sensory nerve conduction velocities, late responses, thermal discrimination thresholds, vibration perception thresholds and pain scores were studied. We were not able to show any positive effect of the drug and therefore conclude that cyclandelate is not effective in the treatment of diabetic neuropathy.

Adult↗
PubMed1990

Accuracy and interobserver variation in the interpretation of computed tomography in solitary brain lesions.

The clinical data and computed tomographic findings of 64 patients with solitary supratentorial brain lesions were presented to two panels of six experienced clinicians. The diagnoses predicted by these clinicians were compared with each other (interobserver variation) and with the definite diagnosis, which in almost all cases was based on histologic examination of the involved tissue (validity of predicted diagnosis). The interobserver agreement was only moderate. The predicted diagnoses agreed with the definite diagnoses in only 57% of cases. A high number of errors were made in distinguishing between high-grade and low-grade glioma and between high-grade glioma and cerebral metastasis, and in the detection of primary cerebral lymphoma. Possible implications of these findings for clinical practice are discussed.

Adult↗
PubMed1990

Stenting of the ureterovesical anastomosis in pediatric renal transplantation.

From January 1985 to July 1989, 36 children received a renal transplant at our hospital. Their ages ranged from 2 to 18 years. All patients had a standard neoureterocystostomy according to Lich-Grégoir. In the first 18 patients, no transanastomotic stent was placed. In the latter 18, a transanastomotic stent with or without suprapubic bladder drainage was performed. In the nonstented group, six severe urological complications occurred, two of which eventually resulted in loss of the transplant. In the stented group, only one severe urological complication occurred. No kidneys in this group were lost due to urological complications. The number of urinary tract infections in the nonstented group was the same as in the stented group.

Adolescent↗
PubMed1990

Transplacental induction of membranous nephropathy in a neonate.

We report a case of renal failure in a newborn infant due to membranous glomerulonephritis. The patient was anuric in the first 3 weeks of life, after which renal function recovered. The serum of the mother contained IgG antibodies which reacted with tubular brush borders and glomeruli of adult and fetal human kidneys. Reactivity with renal epithelium from human kidneys was detected. We suggest that a transplacental, passive Heymann nephritis-like mechanism was the pathogenesis of the neonate's symptoms, although the antigen(s) involved was shown not to be gp 330 or any of the renal antigens known to be involved in experimental nephropathies.

Adult↗
PubMed1990

Some introductory remarks on acupuncture in dentistry.

In general two different types of acupuncture are used in dentistry, Traditional Chinese Acupuncture and Acupuncture according to Dr. Voll. Both use imaginary lines, called channels, according to theories of Traditional Chinese Medicine. However fundamental differences between the two types of acupuncture exist.

Acupuncture Therapy↗
PubMed1989

Vaginal sensitivity to electric stimuli: theoretical and practical implications.

Vaginal sensitivity was investigated in a group of 60 volunteers by means of an electric stimulus and under nonerotic conditions. In comparison to the dorsum of the hand, the genital area has a low sensitivity for electric stimuli (p less than 0.001). Of the genital area, the vaginal wall measured 2 to 4 cm from the vaginal introitus was found to be very insensitive (p less than 0.05). Within the vaginal wall a relatively sensitive position to electric stimuli could be detected at the "12-hr position" (the anterior vaginal wall) (p less than 0.001). The study provides data underscoring previous anatomical and clinical research findings regarding the sensitivity of the anterior vaginal wall. The inefficiency of coitus for inducing female orgasm is discussed.

Adolescent↗