Search PubMed⌕ Search

Biomedical subjects

K Hartmann

Publications and source records attributed to K Hartmann.

At least 145 records · Page 8Linked to original sources
PubMed1989

Demonstration of type I insulin-like growth factor receptors on human platelets.

Human platelets, freshly isolated from healthy human adults, express receptors for insulin-like growth factor I. The IC50 for displacement of 125I-IGF-I binding by unlabeled IGF-I was 0.2 nM, by IGF-II 32 nM by insulin 160 nM. Scatchard analysis of IGF-I binding demonstrates dissociation constants of 0.14 +/- 0.08 nM for high affinity binding site and 54 +/- 18 nM for low affinity binding site. The presence of the alpha-subunit of type I IGF receptor, as high affinity binding site, was verified by affinity crosslinking of 125I-IGF-I to platelet surface membranes. Under reducing con-conditions a Mr = 135,000 band was preferentially labeled. The complete type I IGF receptor complex, which revealed under nonreducing conditions, has an approximately molecular mass of Mr greater than 400,000. The immunoprecipitation of the 125I-IGF-I cross-linked type I receptor with alpha IR-3 confirmed the results achieved by affinity crosslinking.

Adult↗
PubMed1988

Preparative separation of human B and T lymphocytes by free flow electrophoresis.

An electrophoretic method for the quantitative separation of human B and T lymphocytes in a carrier-free system is presented. The method is based on the fact that B and T lymphocytes show marked overlap in their size and density characteristics, but differ sufficiently in surface charge to be separable by electrophoresis. The technique is performed in phosphate-buffered saline and appears to be especially suitable for the enrichment of nonstimulated, functionally intact lymphocytes which can be directly used for further immunological or biochemical studies.

B-Lymphocytes↗
PubMed1988

Diabetogenic effects of N-nitrosomethylurea in rats.

The influence of a single i.v. injection of 75 or 175 mg N-nitrosomethylurea (NMU)/kg into Wistar rats on plasma glucose, i.p. glucose tolerance, plasma insulin and glucagon, glucose stimulated insulin secretion and release as well as on the biosynthesis of insulin in isolated pancreatic islets have been investigated at set intervals between the 3rd day and the 6th week post injectionem. At the end of the experimental period all NMU-treated animals were alive but had significantly reduced body mass. All animals remained normoglycemic even after the glucose load. 3 days after drug application plasma insulin decreased only insignificantly in the 175 mg NMU-group, whereas plasma glucagon was significantly reduced in both drug-groups; after 3 and 6 weeks the reduction of plasma glucagon was still about 30 percent. In isolated islets the glucose stimulated insulin secretion, the percent stimulation of insulin release and insulin biosynthesis were significantly decreased.

Animals↗
PubMed1988

Effect of streptozotocin on transaminases, creatinine and urea in serum of rats.

This study investigates the diabetes-induced lesions in liver and kidney and in addition the possible side effects of the diabetogenic substance streptozotocin (SR) on these organs in non-diabetic animals. 5-week-old female Wistar rats were injected 65 or 130 mg SR/kg body mass. Some animals of the drug group did not become hyperglycemic; thus it was possible to separate the drug effect from the diabetic influence on liver and kidney. In serum investigations some metabolic changes concerning the activities of the liver enzymes aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and the concentrations of urea and creatinine up to 30 days after drug application were studied. SR in hyperglycemic animals causes a time and dose dependent rise in all investigated parameters. Also in normoglycemic rats a significant increase in alkaline phosphatase and in creatinine was observed after 10 days. After 21 and 30 days there were no differences compared to untreated control rats, whereas elevated levels were observed in the hyperglycemic rats. Thus our results support the view of a short damaging effect of SR on liver and kidney without inducing a diabetic state; in hyperglycemic rats the damaging effect is more pronounced.

Alanine Transaminase↗
PubMed1988

Brain structure and function in sexual molesters of children and adolescents.

Sixteen men incarcerated in a state psychiatric facility pursuant to sexual molestation of children and/or adolescents were evaluated by computed tomography (CT) head scans and regional cerebral blood flow (rCBF) estimation. Compared with controls, child molesters were found to have thinner and less dense skulls and lower rCBF values. Variations from control values in rCBF and characteristics of CT head scans for the sex offenders suggest a role for cerebral dysfunction in the etiology of their aberrant behavior.

Adult↗
PubMed1987

[Case reports in pediatric psychiatric education].

Casuistic seminars with case demonstrations, though considered an essential addition of lectures in (child-) psychiatry, sometimes provoke objections particularly amongst students of pedagogy and psychology. The article reflects upon some aspects of the conflict.

Child↗
PubMed1986

The influence of early postnatal overnutrition on peripheric thyroxine metabolism in rats.

The influence of postnatal overnutrition on thyroid metabolism in later life was studied in male rats reared in small nests (2 pups per dam). At an age of 3 months postnatally overfed rats differ from normally bred rats (12 pups per dam) by a significant higher thyroxine and lower triiodothyronine concentration in plasma. Kinetic data of thyroxine metabolism point out a lower fractional turnover rate and a lower metabolic clearance rate per 100 g body mass corresponding with a reduced 131I-uptake by the thyroid gland. A lower energy intake per metabolic mass unit and a lower energy need for maintenance in postnatally overfed rats calculated from intake and body mass development are discussed in respect of correlations between changes of thyroid hormone metabolism and efficiency of energy utilization.

Animals↗
PubMed1986

[Gastrointestinal disorders in psoriatic arthritis].

Systemic amyloidosis is a rare complication in psoriatic arthritis, 16 cases only were published until now. Our case report is characteristic of gastrointestinal symptoms like chronic diarrhea, malabsorption, and intestinal pseudoobstruction. In addition, in this connection the first report of segmental pseudomembranous enteritis is given. Discussing the findings, observations and literature, the difference between psoriatic enteropathy, malabsorption in systemic amyloidosis and pseudomembranous enteritis in amyloidosis is shown. In this connection the basic different pathophysiological mechanisms are demonstrated.

Amyloidosis↗
PubMed1985

Computerized assessment of self-monitored blood glucose results using a Glucometer reflectance photometer with memory and microcomputer.

A microcomputer software package to receive, analyse, and present blood glucose/time information has been developed. Data input is accomplished automatically via interface to Glucometer reflectance photometer instruments which have been specially modified to retain glucose/time results by addition of a clock and electronic memory. This new development in self-monitoring of blood glucose (SMBG) has a number of advantages. It allows the rapid and meaningful analysis of large quantities of patient generated data to assess short- and long-term trends in BG patterns, and eliminates the tedium and possible errors of manual graphing. Patients were most interested in the positive feedback provided. The system has considerable potential in patient diabetes education and management.

Blood Glucose↗
PubMed1985

Distribution of 125I-thyroxine in different organs and tissues of dietically obese rats.

The distribution of 125I-thyroxine (% dose/g tissue; tissue/plasma radioactivity ratio) was investigated in different tissues of 28-week-old obese Wistar rats. Obesity was induced by high-fat diet (HFD) and confirmed by carcass analysis; in heavy obese animals the relative and absolute fat content is increased twofold and threefold, respectively, compared to control rats fed on a low-fat diet (LFD). Heavy HFD rats exhibit diminished 125I-T4 distribution in the "slow pool" (fat tissue, muscle) and unchanged values in the "fast pool" (liver, kidney) in comparison with LFD rats with low body weight. The differences in distribution presented here are not caused by the diet per se, but they are the consequence of the obesity of the animal, because no differences in the 125I-T4 distribution were found in the 125I-T4 between HFD and LFD rats with relatively equal body weight and body composition. The reduced T4 distribution in the fat tissue of obese rats is discussed in connection with possibly decreased lipolysis in this tissue and possible causal participation in the beginning of obesity.

Adipose Tissue↗
PubMed1985

Enhanced formation of benzo(a)pyrene:DNA adducts in monocytes of patients with a presumed predisposition to lung cancer.

Blood monocytes from 45 selected patients with lung cancer and 30 healthy controls were incubated with [G-3H]-benzo(a)pyrene for 30 h, and the formation of covalently bound DNA adducts was determined. The lung cancer patients were either relatively young (below 46 yr), nonsmokers, or had at least one first degree relative with lung cancer. Therefore, they might be considered cancer prone. The DNA adducts were significantly elevated in 22 patients with early age cancer (4.34 fmol/micrograms of DNA; P less than 0.04). In 12 familial cases, the slight elevation (2.77 fmol/micrograms of DNA) was not statistically significant in comparison to healthy controls. Benzo(a)pyrene:DNA adduct levels did not differ significantly between smokers and nonsmokers. Eight of 9 lung cancer patients with DNA adducts equal or above 4.5 fmol/micrograms of DNA but only 16 of 36 with adducts below this value had either oat cell or squamous cell cancer (P less than 0.05). The observed enhanced formation of covalent DNA adducts in blood monocytes exposed to a carcinogenic polycyclic hydrocarbon may be genetically determined and could play a role in the development of lung cancer at an early age.

Adult↗
PubMed1984

Reliability of blood glucose monitoring by patients with diabetes mellitus.

Nineteen patients with insulin-dependent diabetes mellitus were evaluated for overall reliability of self-generated data from capillary blood glucose monitoring. For a period of 12 to 14 days, standard reflectance meters used by these subjects were replaced by meters internally modified with memory chips capable of storing all glucose readings by date and time. The subjects were not aware of this modification and were instructed to continue to test capillary blood glucose as they had been and to continue their practice of recording the meter readings in a logbook. To assess reliability of patient-generated data as recorded in the logbook, the addition, deletion, and alteration of test results were determined. A significantly lower (p less than 0.0001) mean blood glucose level was reported in the logbooks than recorded in the memory reflectance meters. Differences in logbooks and memory reflectance meters ranged from 0 to 109 mg/dl. Three fourths of the subjects had reported lower than actual mean blood glucose values. Under-reporting, or omission of memory reflectance meter readings, averaged 10 percent, whereas over-reporting or addition of phantom values averaged 40 percent. An average of 26 percent of the logbook entries were not identical to memory reflectance meter values determined at the corresponding time. Two thirds of the subjects had reported values in such a manner as to obscure hyper- and hypoglycemia, leading to misleading clinical impressions about the fluctuation in metabolic control. Previous glycemic control, patterns of logbook recording, or visits to the clinic were not found to be predictive of the reliability of patient self-monitoring regimens.

Adolescent↗