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Biomedical subjects

G Hoffmann

Publications and source records attributed to G Hoffmann.

At least 145 records · Page 8Linked to original sources
PubMed1990

Converting enzyme inhibition and vascular prostacyclin synthesis: effect of kinin receptor antagonism.

The effects of angiotensin I-converting enzyme (ACE) inhibitors and bradykinin (BK) on prostacyclin (PGI2) production in isolated arterial tissue were investigated. Rings of rat abdominal aorta were incubated in Krebs-Ringer bicarbonate buffer and PGI2 generation was assessed by the determination of its stable hydrolysis product; 6-keto-PGF1 alpha. The addition of both ACE inhibitors, captopril and lisinopril, and bradykinin resulted in dose-dependent stimulation of PGI2 biosynthesis when the individual substance was added into the incubation buffer at final concentrations between 10(-8) and 10(-5) M. The bradykinin-induced stimulation of PGI2 synthesis was dose dependently inhibited by the BK receptor antagonist, D-Arg[Hyp3, Thi5,8, D-Phe7]BK. The captopril- and lisinopril-induced stimulation of vascular 6-keto-PGF1 alpha production was also significantly decreased when the BK antagonist was added to the incubation medium together with the ACE inhibitors. Our results show that both captopril and lisinopril stimulate PGI2 synthesis in arterial tissue and that this effect may be secondary to changes in the activity of the kinin system.

6-Ketoprostaglandin F1 alpha↗
PubMed1990

[Ultrasonic diagnosis of fetal triploidy].

It can be assumed that among the most frequent pointers to triploidy are the sonographic proof of the existence of a voluminous and vacuolic placenta, early retardation of growth, and the presence of an oligohydramnios. Occasionally, other malformations are also observed, such as hydrocephalus or neural tube defects. Sonographic findings are demonstrated in two cases of triploidy found to exist before the 24 weeks of pregnancy in the living foetus. The clinical signs and patterns are discussed.

Abnormalities, Multiple↗
PubMed1990

Suppression of experimental autoimmune encephalomyelitis by sulfasalazine.

It has recently been suggested that the sulfidopeptide leukotriene C4 (LTC4), a 5-lipoxygenase product of the arachidonic acid metabolism and one of the most potent mediators of vascular permeability, might be involved in the pathogenesis of experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis (MS). Subsequently, 20 guinea pigs with EAE were treated with sulfasalazine, a substance with a proved leukotriene inhibiting effect, which has previously been described as exerting beneficial effects in patients with inflammatory bowel disease and rheumatoid arthritis. The sulfasalazine-treated guinea pigs showed a significantly better clinical outcome, as well as a significantly lower histological inflammation score compared with 19 controls.

Animals↗
PubMed1990

[GnRH-agonists in the therapy of endometriosis].

Repeated application of GnRH agonists causes a reversible suppression of ovarian function. Suppression on estrogen release is the fundamental idea of this hormonal therapy of endometriosis. We treated twelve patients with histologically proved endometriosis with leuprolide acetate depot in a dose of 3.75 mg s.c. every 4 weeks over a period of 6 months. In the first week of therapy the estrogen level decreased to a post-menopausal niveau along with amenorrhoea during the entire period of therapy. Complaints previous to therapy such as dysmenorrhoea, pelvic pain and dyspareunia were relieved or completely disappeared after therapy. The clinical finding on palpation also diminished or disappeared. In addition to this finding pelvis copy showed a shift from severe endometriosis stage III and stage IV to stage I and stage II of the AFS classification 1985. Regular menstruation appeared in 5 to 9 weeks after the last application to all patients. Out of six cases of infertility, four patients became pregnant. Except for one case, typical menopausal symptoms appeared, such as flush, increased perspiration and sleeping disorders. During and after therapy we could not prove any changes in the lipid metabolism under estrogen therapy. Mineralization of the bone decreased under therapy by about 3%. Simultaneously, serum osteocalcin increased. Demineralization occurred with one exception within the normal range for the corresponding age. With identical efficiency but less side effects, we see therapy with GnRH agonists as an alternative to current hormonal therapy of endometriosis.

Adolescent↗
PubMed1990

[Ecosystems with special reference to development of resistance].

Pests and ectoparasites may cause considerable damage to health or impair the well-being of humans and domestic animals in the open as well as indoors. They may do so as vectors of diseases, producers of allergens and/or toxins and also as causes of repulsion and nuisances. Further detrimental factors of their occurrence may consist e.g. in damage to foods and feeds as well as materials used for insulation of apparatus, textiles, packaging materials, wood etc. In addition, measures to control pests and parasites may affect the habitats of non-target animals, e.g. larvicides applied to liquid manure, or products to control breeding of mosquitoes and blackflies. Such measures may result in hazards for surface water, ground water and soil from residues of the products applied. In the indoor environment, the users of rooms may become exposed, over extended periods, to contamination resulting from the desorption of insecticides or acaricides from the material treated. Increasing and often complex resistance to the active ingredients of the products used means a qualitative and quantitative intensification of the generation of residues. To be able to minimize such problems, exact knowledge of type, spectrum, intensity and dynamics of the resistance presence are required. However, systematic inquiries into the problem are not conducted in the Federal Republic of Germany.

Animals↗
PubMed1990

3-Hydroxy-3-methylglutaryl coenzyme A reductase activity in cultured fibroblasts from patients with mevalonate kinase deficiency: differential response to lipid supplied by fetal bovine serum in tissue culture medium.

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity was measured in extracts of cultured fibroblasts derived from patients with mevalonate kinase deficiency (MKD). For six patients studied, the mean activity of 63.3 +/- 41.1 pmol/min-mg protein (+/- 1 SD, range 37.7-146.2) was significantly higher than the mean value in three control fibroblast lines of 11.1 +/- 3.5 (+/- 1 SD, range 8.0-14.9). These values were obtained using cells subcultured in medium supplemented with 10% fetal bovine serum (FBS) 21 h prior to assay. When cells were deprived of cholesterol by subculturing for 21 h in delipidated FBS, the mean value for patient cells was increased to 230.8 +/- 78.5 pmol/min-mg protein (range 130.9-333.8) as compared to 109.5 +/- 47.1 (range 78.0-163.6) for controls. The activity of HMG-CoA synthase in extracts of fibroblasts derived from the patients was not elevated. The mevalonic acid concentration in the surrounding culture medium was assessed by stable isotope dilution assay. For five patients, the mean concentration in medium containing FBS was 0.92 +/- 0.37 microM (+/- 1 SD, range 0.46-1.48) in contrast to 1.24 +/- 0.83 microM (range 0.46-2.54) for cells subcultured in delipidated FBS. The mean value for three control fibroblast lines was 0.22 +/- 0.12 microM (+/- 1 SD, range 0.11-0.35) for cells subcultured in FBS as compared to 0.01 +/- 0.01 microM (range 0.0-0.01 microM) for cells sucultured in delipidated FBS.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Evaluation of reflux behavior of esophago-jejunal anastomoses following gastrectomy].

Functional results of 48 gastrectomies are reported. The applied techniques of the construction (jejunoplicatio) are judged for the safety of the anastomosis. 29 patients (60.5%) were examined for the degree of jejunooesophageal reflux after a survival time of 1 year. Antireflux techniques of anastomosis had good functional results measured by manometry and pH-metry.

Anastomosis, Roux-en-Y↗
PubMed1989

Effects of oxymorphazone in frogs: long lasting antinociception in vivo, and apparently irreversible binding in vitro.

Oxymorphazone (at doses of 50-200 mg/kg) was found to be a relatively weak antinociceptive drug in intact frog (Rana esculenta) when acetic acid was used as pain stimulus. Frogs remained analgesic for at least 48 hrs following oxymorphazone (200 mg/kg) administration. The ligand increased the latency of wiping reflex in spinal frogs too. These effects were blocked by naloxone. In equilibrium binding studies (3H)oxymorphazone had high affinity to the opioid receptors of frog brain and spinal cord as well (apparent Kd values were 8.9 and 10.6 nM, respectively). Kinetic experiments show that only 25% of the bound (3H)oxymorphazone is readily dissociable. Preincubation of the membranes with labeled oxymorphazone results in a washing resistant inhibition of the opioid binding sites. At least 70% of the (3H)oxymorphazone specific binding is apparently irreversible after reaction at 5 nM ligand concentration, and this can be enhanced by a higher concentration of tritiated ligand.

Analgesics↗
PubMed1989

Analysis of follicle-cell functions in Drosophila: the Fs(3)Apc mutation and the development of chorionic appendages.

Fs(3)Apc is a dominant female-sterile mutation of Drosophila melanogaster which causes an incomplete migration of follicle cells between the oocyte and the nurse cells. This leads to leakage of anterior egg cytoplasm followed by degeneration of the egg primordium or deposition of flaccid eggs with reduced anterior egg coverings including the dorsal appendages. Analysis of ovarian and germ-line chimeras revealed that the focus of the Apc phenotype is located in the ovarian soma. Apc+ clones, induced by mitotic recombination, lead to the formation of "exceptional" eggs with (often partial) rescue of the mutant phenotype. Analysis of Apc+ mosaics shows that the Apc mutant phenotype depends on the genotype of the anterior follicle cells. The patterns of apparent Apc+ clones suggest that there is no lineage restriction between the follicle cells that form the anterior egg coverings and those that form the dorsal appendages at the follicle envelope stage.

Animals↗
PubMed1989

[Diagnosis of hypophyseal abscess using MRI and high resolution CT].

Preoperative diagnosis of pituitary abscess is very difficult. In particular, differentiation from other cystic processes of the sellar region is delicate. The clinical and radiological findings of a case of pituitary abscess are presented. Since CT and MRI are of major importance for routine pituitary screening, the aspects of these methods are emphasized. In our experience, both methods can contribute to preoperative diagnosis.

Adenoma↗
PubMed1989

Isolation and characterization of dominant female sterile mutations of Drosophila melanogaster. II. Mutations on the second chromosome.

Twenty-four, second chromosome, dominant female sterile (Fs) mutations in Drosophila are described. Fs(2) were isolated at a frequency of approximately 1 per 1000 EMS-treated chromosomes screened. In comparison the isolation of frequency for second chromosome zygotic recessive lethal mutations was approximately 550 per 1000. Complementation analysis of the Fs(2) revertants showed that the 24 Fs(2) mutations identify 13-15 loci, calculated to be about 65-75% of the second chromosome genes EMS mutable to dominant female sterility. Two of the Fs(2) mutations are useful tools for the dominant female sterile technique: Fs(2)1 for induction and detection of germ-line clones and Fs(2)Ugra for follicle cell clones. Several of the Fs(2) mutations bring about novel mutant phenotypes. Seven of them alter egg shape, whereas the others arrest development primarily at two stages: around fertilization by five Fs(2) and during cleavage divisions [by Fs(2) in three loci]. The remaining that allow development to the larval stage of differentiation include four new dorsal alleles and one dominant torso allele. Analysis of germ-line chimeras revealed that with two exceptions all the Fs(2) mutations are germ-line dependent. The Fs(2) mutations were mapped mainly on the basis of mitotic recombination induced in the female germ-line cells of adult females. That most of the Fs(2) may be gain-of-function mutations is indicated by the unusual behavior of the Fs+ germ-line clones and also by the fact that 90% of the could be induced to revert.

Animals↗
PubMed1989

Suppression of experimental autoimmune encephalomyelitis by dual cyclo-oxygenase and 5-lipoxygenase inhibition.

The release of leukotriene C4 (LTC4), an important 5-lipoxygenase product of the arachidonic acid metabolism from polymorphonuclear leucocytes (PMNLs) of guinea pigs with experimental allergic encephalomyelitis (EAE), the animal model of MS, has been found to be significantly increased compared with healthy animals. Subsequently, the dual cyclo-oxygenase and 5-lipoxygenase inhibitor BW755C was applied to 15 guinea pigs with EAE. Two control groups (15 each) were treated with the cyclo-oxygenase inhibitor indomethacin or physiological saline, respectively. In the BW755C treated group, no animal developed symptoms of the disease in contrast to, respectively, 5 and 3 animals in the 2 other groups. Histological examination of the CNS revealed a highly significantly lower inflammation score in the BW755C treated animals, and the release of LTC4 from PMNLs was highly significantly decreased in this group compared with each of the others. The findings suggest that the vascular permeability enhancing LTC4 plays a pathogenetic role in EAE and indicate that inhibition of this sulfidopeptide leukotriene suppresses the disease. Therefore, the application of leukotriene inhibitors could contribute to the future treatment of MS.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed1989

Mevalonate kinase in lysates of cultured human fibroblasts and lymphoblasts: kinetic properties, assay conditions, carrier detection and measurement of residual activity in a patient with mevalonic aciduria.

An assay has been developed for the measurement of mevalonate kinase activity in extracts of cultured human fibroblasts and lymphoblasts. Individual elements of the assay were investigated in order to achieve optimum conditions. Apparent Michaelis constants (KMapp) for the substrates mevalonic acid and adenosine-5'-triphosphate were 22 +/- 10 mumol/l and 0.42-0.53 mmol/l, respectively, in lysates of control fibroblast lines. The same values in lysates of a control lymphoblast line were 17 mumol/l and 0.23 mmol/l, respectively. Mevalonate kinase activity in extracts of cultured fibroblasts derived from 6 control individuals was 3.24 +/- (SD) 0.91 nmol/min/mg protein. The activity in extracts of fibroblasts derived from a patient with mevalonic aciduria was 0.15 +/- 0.10 nmol/min/mg protein, approximately 5% of the control mean. The parents and brother of the patient displayed mevalonate kinase activities in fibroblast extracts approximating 38-42% of the control mean. Substantially higher mevalonate kinase activity was documented in extracts of cultured lymphoblasts. When assayed on various occasions, the mean activity of mevalonate kinase in extracts of lymphoblasts derived from the parents, brother and maternal grandmother of the patient ranged from 27 to 32% of the mean activity of 9.8 +/- (SD) 3.4 nmol/min/mg protein measured in a parallel control lymphoblast line, while the mean activity in a maternal and paternal uncle approximated 65-89% of the same control mean. The mean activity in extracts of lymphoblasts derived from the patient approximated 2% of the control mean. The data suggest that the parents, brother and maternal grandmother are carriers of the defective gene responsible for mevalonate kinase deficiency, consistent with an autosomal recessive mode of inheritance.

Cells, Cultured↗
PubMed1989

Insulinotropic properties of synthetic human gastric inhibitory polypeptide in man: interactions with glucose, phenylalanine, and cholecystokinin-8.

The quantitative contribution of glucose-dependent insulinotropic polypeptide [gastric inhibitory polypeptide (GIP)] to the incretin effect after oral glucose (augmentation of insulin secretion over the degree that is explained by the glycemic rise) is not known. Therefore, hyperglycemic clamp experiments (8 mmol/L, corresponding to postprandial glucose concentrations) were performed in healthy volunteers, and synthetic human GIP was infused for 60 min at a rate (approximately 1.3 pmol/kg.min) that results in plasma GIP concentrations similar to those occurring after oral glucose loads of 75 g. The MCR for exogenous GIP was approximately 6 mL/kg.min; the decay after ceasing infusion was exponential with a t1/2 of about 18 min, and the resulting volume of distribution was about 140 mL/kg. At euglycemic (basal) plasma glucose concentrations (5.0 mmol/L) similar values were found. Insulin secretion was stimulated by hyperglycemia alone, but was greatly (2.3-fold based on C-peptide) potentiated by GIP infusions (P less than or equal to 0.001 for integrated incremental values). When integrated incremental responses over 120 min of GIP, immunoreactive insulin, and immunoreactive C-peptide were compared after oral glucose and during GIP infusions, no significant differences were found. Peak glucose concentrations after oral glucose (7.6 +/- 0.6 mmol/L) were similar to mean plasma glucose values during clamp experiments (8.2 +/- 0.1 mmol/L; P = 0.124). However, mean glucose concentrations after oral glucose were lower (6.0 +/- 0.3 mmol/L; P = 0.0004). Additional infusion of sulfated cholecystokinin-8 (25 pmol/kg.h) or the amino acid phenylalanine (1.7 mumol/kg.min) did not further stimulate insulin secretion and had no influence on the pharmacokinetics of exogenous GIP. It is concluded that human synthetic GIP is insulinotropic in man and that this activity may well explain a substantial part of the incretin effect after oral glucose. There is no interaction with cholecystokinin or phenylalanine in concentrations found after mixed meals.

Adult↗