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Biomedical subjects

H Schmidt-Gayk

Publications and source records attributed to H Schmidt-Gayk.

At least 109 records · Page 6Linked to original sources
PubMed1987

Ramipril and captopril in patients with heart failure: effects on hemodynamics and vasoconstrictor systems.

Fifteen patients with congestive heart failure (New York Heart Association III) were randomly assigned to treatment with either captopril or ramipril, a newly developed angiotensin converting enzyme inhibitor. Both groups were similar with respect to baseline hemodynamic measurements and plasma levels of norepinephrine, renin and vasopressin. The group receiving ramipril showed hemodynamic changes comparable to the group receiving captopril on the seventh day of treatment. The stroke volume index increased by 20% versus 21%, respectively, and the total peripheral resistance decreased by 13% versus 20%, respectively. The decrease in blood pressure and the tendency to decrease heart rate were similar in both groups. All patients had reactive hyperreninemia during therapy with the converting enzyme inhibitor. The resting elevated plasma norepinephrine decreased in both groups significantly, whereas vasopressin did not change. The hemodynamic improvement was more pronounced and comparable in both groups during exercise. Thus, ramipril is equally effective compared with captopril in the treatment of patients with severe congestive heart failure.

Adult↗
PubMed1987

Antiepileptic drugs reduce serum uric acid.

Uric acid examination in 554 epileptic out-patients under long-term anticonvulsant medication revealed significantly lower serum concentrations compared to a group of normal controls. In patients taking enzyme-inducing drugs, uric acid levels were found to be lower than in those under valproate sodium. In addition, uric acid concentrations showed a negative correlation with duration of therapy in epileptic males. At this time, we can only speculate on the mechanism involved in the reduction of uric acid by enzyme-inducing anticonvulsants as well as on the possible implication of this finding in the treatment of hyperuricemia.

Adult↗
PubMed1987

Sensitive homologous radioimmunoassay for human parathyroid hormone to diagnose hypoparathyroid conditions.

A sensitive radioimmunoassay for human parathyroid hormone (hPTH) to diagnose hypoparathyroid conditions is described. The antiserum was raised in goats against extracted hPTH. Synthetic human PTH fragment (53-84) is used as a standard and 125I-Tyr52hPTH (53-84) as a tracer. After a two-step incubation (24 h + 24 h) at 4 degrees C, the bound and free fractions are separated by a mixture of second antibody and polyethylene glycol solution. The detection limit for hPTH (53-84) is 2 pmol/L hPTH (53-84) (2 mol/tube). The PTH level in 36 healthy subjects was 5-12 pmol/L. Of 14 patients with hypoparathyroidism 11 patients had PTH concentrations below normal, two patients had levels on the lower limit of the normal range (5 pmol/L). The concentration of one patient with pseudohypoparathyroidism was markedly elevated. This assay is suitable for detecting low PTH levels and for studying changes of PTH concentration within the normal range.

Calcium↗
PubMed1987

Evaluation of Ca 12-5 as a tumor marker for gastric and colo-rectal cancer in comparison to CEA and Ca 19-9.

We performed simultaneous measurements of CA 12-5, CEA and Ca 19-9 in the preoperative sera of 87 patients with gastric cancer, 177 patients with colo-rectal cancer and 55 patients with benign diseases. 5.6% of the control patients, 13.8% of the gastric cancer patients and 9.6% of the colo-rectal cancer patients showed Ca 12-5 values of 27.0 U/ml and more. In contrast, the sensitivity of the tumor markers CEA (greater than or equal to 5.0 ng/ml in 17.1% of the gastric cancer and 36.2% of the colo-rectal cancer patients examined) and Ca 19-9 (greater than or equal to 25.0 U/ml in 16.1% of the gastric cancer and 19.8% of the colo-rectal cancer patients) was distinctly higher. The simultaneous determination of three markers on the one hand increased the rate of 'marker-positive' patients (up to 34.5% in gastric cancer and 45.2% in colo-rectal cancer) but on the other hand diminished the specificity (from 96.4% to 89.1%) of the examination.

Antigens, Neoplasm↗
PubMed1987

Measurement of intact human parathyrin by an extracting two-site immunoradiometric assay.

This is an immunoradiometric assay of intact human parathyrin, hPTH(1-84). One antibody, directed against the N-terminal part of the hormone, was produced in goats and conjugated covalently to cellulose particles. hPTH(1-84) and the N-terminal fragments were extracted from EDTA-treated plasma by these particles and thus concentrated. Another antibody, against synthetic hPTH(53-84), was raised in rabbits; this bound to the C-terminal part of the hormone. The final step was labeling the second free binding site of this antibody with 125I-labeled Tyr52-hPTH(53-84) and measuring the bound radioactivity. This assay can detect intact PTH in concentrations as low as 0.6 pmol/L (1.2 X 10(-16) mol per tube). The assay did not cross react with hPTH(1-34), hPTH(1-44), hPTH(28-48), hPTH(39-84), hPTH(44-68), or hPTH(53-84) in concentrations up to 6400 pmol/L. In 60 normal subjects, hPTH(1-84) concentrations ranged from 1.9 to 6.8 pmol/L; in 32 patients with primary hyperparathyroidism, from 7.0 to 80 pmol/L. The hormone was not detected in four patients with hypoparathyroidism.

Antibodies, Monoclonal↗
PubMed1986

Increased heterogeneity of serum thyroglobulin in thyroid cancer patients as determined by monoclonal antibodies.

We investigated the immunological heterogeneity of plasma Tg in thyroid cancer patients using monoclonal antibodies in an immunoradiometric assay and a conventional RIA system with a polyclonal rabbit antibody. The results were compared with measurements of plasma Tg in patients with nonmalignant disease. We can demonstrate an increased immunological heterogeneity in tumor patients compared with patients with non-malignant thyroid diseases. In one case the Tg value measured by a monoclonal test system exceeded the value obtained by a polyclonal RIA system in the same sample by a factor of 25. It has to be further investigated whether this increase in heterogeneity is of diagnostic value in the follow-up of thyroid cancer patients.

Adenocarcinoma↗
PubMed1986

Metastatic C-cell carcinoma: calcitonin and CEA production in monolayer culture.

Mechanically dissociated cells from a surgically removed mediastinal C-cell carcinoma (MTC) were cultured over a period of 4 months. The cells of the monolayer culture consisted of clusters of small epithelial-like cells. Using semithin and ultrathin sections, two different types of cells could be characterized by shape of nucleus and by content and distribution of secretory granules. One type of cell showed a more irregularly shaped nucleus, the other contained a large oval nucleus, similar to the normal C-cell of the human thyroid. Calcitonin (CT) and carcinoembryonic antigen (CEA) were measured in supernatants in duplicate by radioimmunoassays. Radioimmuno-detectable CT levels in the supernatant of culture medium varied between 0.8 and 1.6 ng/ml and CEA levels between 5 and 27 ng/ml during a 2-month period. The present study proves that in monolayer-cultured cells of a MTC, metastases continue to produce radioimmuno-detectable CT and CEA. Whether the two different cell types in culture are relevant for carcinoma needs further investigation.

Adult↗
PubMed1986

The association of hyperlipoproteinemia with dysimmunoglobulinemia.

In a study of the immunoglobulin concentrations in an urban population and in patients with hyperlipoproteinemia we observed significant positive correlations between serum triglycerides and IgA independent of sex, age and body weight. In men serum triglycerides also correlated with IgG and IgM, and serum cholesterol with IgA. The prevalence of hyper- and hypoimmunoglobulinemia was significantly higher in hyperlipidemic than in normolipemic subjects. We propose that the occurrence of hyperlipoproteinemia with hypoimmunoglobulinemia may be caused by different pathobiological mechanisms than the occurrence with hyperimmunoglobulinemia.

Adult↗
PubMed1986

Chronic ethanol consumption selectively stimulates rectal cell proliferation in the rat.

Cell proliferation was examined in the gastrointestinal tract of 30 pair fed rats having received an isocaloric liquid diet containing 36% of total calories either as ethanol or carbohydrates for four weeks. Utilising the metaphase arrest technique with vincristine, cell proliferation was measured as crypt cell production rate. This was selectively increased in the rectal mucosa of ethanol fed rats (19.1 +/- 2.0 vs 9.1 +/- 1.8 cells/crypt/h; p less than 0.005). There was a concomitant increase in proliferative compartment size (48.1 +/- 5.6% vs 30.1 +/- 8.5% of crypt population size; p less than 0.001). Serum gastrin concentrations were also found to be significantly increased after ethanol feeding (172 +/- 51 vs 106 +/- 27 pmol/l; p less than 0.01). The ethanol dependent proliferative changes in the rectal mucosa are predictive of higher susceptibility of this site to carcinogenesis, supporting experimental and epidemiological data. Increased gastrin concentrations may partly explain the observed rectal hyperproliferation. Other possible causes cannot, however, be excluded.

Alcohol Drinking↗
PubMed1986

Two homologous radioimmunoassays for parathyrin compared and applied to disorders of calcium metabolism.

These 48-h homologous equilibrium radioimmunoassays for human parathyrin (hPTH) are based on the use of two antisera, MS 6 and MS 7, raised in guinea pigs against human parathyroid adenoma extract. For the assay with MS 6, Tyr43-hPTH(44-68) and hPTH(44-68) were radioiodinated for use as the assay tracer. Labeled peptides were separated from free iodine by passage through Sep-Pak C18 cartridges. This RIA appears to be mid-region specific: hPTH(28-48) and hPTH(64-84) were not recognized, whereas hPTH(53-84) was 100% cross reactive with hPTH(44-68). Thus, the PTH recognition site of antiserum MS 6 must be between amino-acid residues 53 and 63. With antiserum MS 7, which recognized the PTH molecule between amino-acid residues 69 and 84, we used hPTH(53-84) for preparing the standard curve and 125I-labeled Tyr52-hPTH(53-84) as the assay tracer. Because this RIA recognized PTH fragments containing residues 69-84 of hPTH, we termed it a C-terminal assay. Both assays were useful for diagnosis of primary and secondary hyperparathyroidism.

Adenoma↗
PubMed1985

[Long-term therapy of familial hypercholesterolemia in young patients with colestipol: availability of minerals and vitamins].

Longterm treatment for 5 years of young patients with familial hypercholesterolemia was accompanied by monitoring of plasma levels of calcium, iron, sodium, parathyroid hormone and water- and fat soluble vitamins, since interference of the ion exchange resin with absorption of numerous substances as well as abnormal plasma levels of some of the above had been described in several studies. Treatment was effective in the group with good compliance (lowering of plasma cholesterol at the end of 5 years by 19% and, compared to the control group, by 23%). Adverse drug effects with respect to the above parameters were not found. Plasma levels of carotinoides and vitamin E were elevated in the patients according to elevated concentrations of lipoproteins which are carriers of these vitamins.

Adolescent↗
PubMed1985

Secretion of calcitonin and carcinoembryonic antigen in long-term organ culture of human medullary thyroid carcinoma: biochemical and immunocytochemical studies.

Tissue cultures of four C-cell carcinomas (medullary thyroid carcinoma, MTC) were prepared to study the basal and stimulated calcitonin (CT) and carcinoembryonic antigen (CEA) release. Immunohistological staining of the explants for CT and CEA have been performed after various periods of culture. These MTC explants were able continuously to release CT and CEA for periods up to 157 days. The spontaneous CT and CEA release decreased sharply during the 1st week of culture, then remained nearly constant over the observation period. THE CEA/CT secretion ratio slightly declined during long-term culture; CEA release seems to drop earlier than CT production. CT and CEA could be detected in the same cells by immunocytochemical technique. The septal tissue consisting of dense connective tissue and amyloid produced by tumor cells seemed to increase during long-term culture. CT, but not CEA, was stimulated by pentagastrin (10(-5) M), glucagon (6 x 10 (-6) M), and dose related by calcium (2.5-20 mM) in vitro. The MTC explant organ long-term culture proved to be a useful model for studies of human CT and CEA secretion.

Adolescent↗
PubMed1985

Calciuric response to 1,25-(OH)2D3 in early renal failure.

In 10 patients with early renal failure (glomerular filtration rate between 30 and 80 ml/min/1.73 m2) without nephrotic syndrome and in 13 controls the calciuric response to increasing oral doses of calcitriol [1,25-(OH)2D3] (0.25; 0.5; 1.0; 1.5 micrograms/day) was evaluated. Patients had initially normal plasma calcitriol levels, normocalcemia and hypocalciuria. With calcitriol doses up to 1 microgram/day, the increment of UVCa was less in patients. Only at 1.5 micrograms/day the calciuria of patients reached the baseline calciuria of controls. The data document that 1.0 microgram calcitriol per day is required to normalize UVCa in patients with early renal failure and normal calcitriol levels. Blunted calciuric response to low doses of calcitriol is compatible with an altered dose-response relationship.

Administration, Oral↗
PubMed1984

A sensitive and simplified radioimmunoassay for 1,25-dihydroxyvitamin D3.

A sensitive radioimmunoassay system for 1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3] with an improved extraction procedure has been developed. Following one-step extraction and prepurification of 1,25(OH)2D3 by 'Extrelut-1' minicolumns final purification was achieved by high-performance liquid chromatography (HPLC) using a radial compression separation system equipped with a mu Porasil cartridge. The HPLC method applied allows the purification of 4 extracts/h. Recovery of 1,25(OH)2[3H]D3 after HPLC was 77 +/- 2.6% (mean +/- SD, n = 51). Since the recovery of 1,25(OH)2[3H]D3 was very reproducible, addition of labelled steroid to each single serum sample for monitoring recovery was omitted. The sensitivity of the assay was 0.8 pg/tube resulting in a detection limit of 3 ng/l, when 1 ml of serum was extracted. Intra-assay and inter-assay coefficients of variation were 12% and 16.8%, respectively. Serum 1,25(OH)2D3 concentration in 30 normal subjects (mean age: 25 yr) was 55 +/- 12 ng/l (mean +/- SD). In 55 elderly patients (mean age: 77 yr) the 1,25(OH)2D3 serum level was 32 +/- 12 ng/l (mean +/- SD) and in three patients with chronic renal failure on 1,25(OH)2D3 therapy 146 +/- 67 ng/l (mean +/- SD). Patients with chronic renal failure had reduced 1,25(OH)2D3 serum levels (mean 5.4 ng/l, range less than 3-11 ng/l, n = 10). In one patient with renal failure, following kidney transplantation the serum 1,25(OH)2D3 and creatinine levels were monitored from the 4th to the 12th post-surgical day: a highly significant negative correlation (r = 0.85) was found.

Adolescent↗