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Biomedical subjects

M Schmidt

Publications and source records attributed to M Schmidt.

At least 667 records · Page 37Linked to original sources
PubMed1991

Subcutaneous gonadotropin therapy in male patients with hypogonadotropic hypogonadism.

OBJECTIVE: The response to subcutaneous (SC) gonadotropin replacement therapy, using human chorionic gonadotropin (hCG) and human menopausal gonadotropin (hMG) or hCG alone, was evaluated in male hypothalamic hypogonadism. DESIGN: Sixteen patients with hypothalamic hypogonadism were treated with gonadotropins for induction of puberty and normalization of spermatogenesis. The results were analyzed retrospectively. SETTING: The study was carried out in a clinical endocrinology department providing tertiary care and in private practices of endocrinology. PATIENTS: Eight patients with idiopathic hypogonadotropic hypogonadism and eight patients with Kallmann's syndrome in prepubertal or early pubertal stages. INTERVENTIONS: Human chorionic gonadotropin and hMG were administered SC in individual dosages. MAIN OUTCOME MEASURES: Increase of serum testosterone (T), testicular volume, semen volume, and sperm count were evaluated. RESULTS: Normalization of serum T and complete sexual maturation was achieved in all patients. Spermatogenesis was induced in all but two patients. Seven patients showed normal findings in semen volume and sperm count, and two patients had semen quality close to normal. In five patients sperm count remained less than 10 x 10(6)/mL. CONCLUSIONS: The results obtained by SC gonadotropin replacement prove this mode of administration to be effective in stimulating steroidogenesis and spermatogenesis in hypogonadotropic males.

Adolescent↗
PubMed1991

Kinetics of expression of ACh receptor alpha-subunit mRNA in denervated and stimulated muscle.

Levels of the acetylcholine receptor (AChR) alpha-subunit mRNA were quantified in chick leg muscle, both after section of the sciatic nerve and following electrical stimulation of the denervated leg musculature. Whereas a lag period of approximately 17 h intervenes between the nerve section and the increase in message level, electrical stimulation leads to an immediate decline, which proceeds with a half-life of 3-4 h, similar to the decay induced by treatment with actinomycin D. The asymmetry in the kinetics of activation and repression can be accommodated by several regulatory schemes of which the simplest contains an autocatalytic loop as recently proposed by Changeux (The New Biologist 3: 413-429, 1991).

Animals↗
PubMed1991

Differentiation of sympathetic neurones projecting in the hypogastric nerves in terms of their discharge patterns in cats.

1. Sympathetic neurones that project in the hypogastric nerves (HGNs) were analysed for their discharge patterns in anaesthetized cats. The activity of these neurones was recorded from their axons. Afferents from the pelvic organs (urinary bladder, colon, anal canal), and arterial baro-and chemoreceptors were stimulated. 150 postganglionic and nine preganglionic neurones were analysed. 2. The postganglionic neurones exhibited reflex patterns that were typical of visceral vasoconstrictor neurones and various types of motility-regulating neurones. Most motility-regulating neurones and all visceral vasoconstrictor neurones had ongoing activity. 3. Postganglionic motility-regulating neurones were not influenced by stimulation of arterial baro-and chemoreceptors, but showed distinctive reflexes on stimulation of afferents from pelvic organs. Three subgroups of motility-regulating neurones were identified: type 1 neurones (34% of the sample of postganglionic neurones) were excited from the urinary bladder and inhibited or not influenced from the colon. Type 2 neurones (14%) exhibited a reflex pattern reciprocal to that of the type 1 neurones. Anal motility-regulating neurones (8%) were only influenced from the anal canal. The most powerful reflexes in these types of motility-regulating neurones were elicited by mechanical stimulation of the anal mucosa. 4. Postganglionic visceral vasoconstrictor neurones (16% of the sample) were under powerful inhibitory control from the arterial baroreceptors and weakly excited by stimulation of arterial chemoreceptors. Visceral stimuli had little or no effect on most of these neurones. Some visceral vasoconstrictor neurones exhibited some overlap in their functional properties with motility-regulating neurones. 5. Twenty-eight per cent of our sample of postganglionic neurones showed no reflexes to the afferent stimuli used. About half of these neurones had on-going activity. 6. Nine preganglionic neurones with on-going activity were identified. Most of these neurones behaved like visceral vasoconstrictor or motility-regulating neurones. 7. This study shows that the majority of postganglionic neurones that project in the HGNs can be divided into the same functional types as the lumbar preganglionic neurones that project to the inferior mesenteric ganglion. The proportions of the different types of neurones are similar at pre- and postganglionic levels. Thus the centrally generated patterns of activity are most likely faithfully transmitted from the spinal cord to the target organs in the pelvic cavity in functionally separate pathways.

Anal Canal↗
PubMed1991

Drosophila as a model system for molecular analysis of tumorigenesis.

In Drosophila, homozygous mutations in a series of genes can cause the appearance of tissue-specific tumors. These tumors occur either during embryonic or larval development. The majority of the identified genes give rise to larval tumors that affect either the presumptive adult optic centers of the brain, the imaginal discs, the hematopoietic organs, or the germ cells. These genes act as recessive determinants of neoplasia and have been designated as tumor-suppressor genes. They are normally required for the regulation of cell proliferation and cell differentiation during development. Among these genes, the lethal(2)giant larvae (l(2)gl) has been best studied. Homozygous mutations in l(2)gl produce malignant tumors in the brain hemispheres and the imaginal discs. The l(2)gl gene has been cloned, introduced back into the genome of l(2)gl-deficient animals, and shown to restore normal development. The nucleotide sequence of the l(2)gl gene has been determined, as well as the sequence of its transcripts. Anti-l(2)gl antibodies recognize a protein of about 130 kDa that corresponds to the major product of l(2)gl transcripts. Analysis of the spatial distribution of l(2)gl transcripts and proteins revealed a first phase of intensive expression during embryogenesis and a second weaker phase during the larval to pupal transition period. As revealed by mosaic experiments, the critical period of l(2)gl expression for preventing tumorigenesis takes place during early embryogenesis. During this period, the l(2)gl protein is ubiquitously expressed in all cells and tissues, while during late embryogenesis expression becomes gradually restricted to the midgut epithelium and the axon projections of the ventral nervous system that show no phenotypic alteration in the mutant animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Microbial metabolism of quinoline and related compounds. XI. Degradation of quinoline-4-carboxylic acid by Microbacterium sp. H2, Agrobacterium sp. 1B and Pimelobacter simplex 4B and 5B.

From soil enrichment cultures four strains, using quinoline-4-carboxylic acid as sole source of energy and carbon, have been isolated. According to their physiological properties these bacteria have been identified as Microbacterium sp. designated H2, as Agrobacterium sp. designated 1b and Pimelobacter simplex designated 4B and 5B. Metabolites of the degradation pathway of quinoline-4-carboxylic acid have been isolated and identified. With Pimelobacter simplex 4B and 5B 2-oxo-1,2-dihydroquinoline-4-carboxylic acid and 8-hydroxycoumarin-4-carboxylic acid were isolated. The Agrobacterium strain accumulated 2-oxo-1,2-dihydroquinoline-4-carboxylic acid and 2-oxo-1,2,3,4-tetrahydroquinoline-4-carboxylic acid in the media during growth; with Microbacterium sp. H2 we only found 8-hydroxycoumarin-4-carboxylic acid. With mutants of Microbacterium sp. H2 which were induced with N-methyl-N'-nitro-N-nitrosoguanidine we found 2-oxo-1,2-dihydroquinoline-4-carboxylic acid, 8-hydroxy-coumarin-4-carboxylic acid and 2,3-dihydroxyphenyl-succinic acid.

Actinomycetales↗
PubMed1991

Chymotrypsin-catalyzed fragment coupling synthesis of GnRH-analogs.

D-Xaa6-GnRH analogs (Xaa: Ala, Nal1), Phe, Ser(tBu), Trp) were prepared by chymotrypsin catalyzed 3 + 7 fragment coupling synthesis with conversion rates of the amino component in the range from 90.3 to 97.4%. For D-Phe6-GnRH the method was scaled up to production level.

Catalysis↗
PubMed1991

[The diagnostic value of conventional x-ray diagnosis and quantitative mineral measurements in patients with clinical symptoms of osteoporosis].

The problem of differentiating between patients suffering from osteoporosis and those with healthy bones is discussed on the basis of distribution of the age-specific and sex-specific mineral salt values in a healthy population and in a population with clinically manifest osteoporosis. By comparing the results of quantitative mineralometry and conventional x-ray films of the human skeleton in a histologically clarified group of persons with clinically manifest osteoporosis signs and symptoms, the diagnostic ranking of both methods is assessed and discussed.

Bone Density↗
PubMed1991

Bisection of bovine morulae and blastocysts from superovulated Danish dairy cows.

Sixtyfour compacted morulae and blastocysts were bisected with a microscalpel. The majority of the demi-embryos (n = 122) were reinserted into separate zona pellucidae (ZP) before non-surgical transfer to 113 synchronized recipients, as singles (n = 98) (DE-S) or in pairs (n = 30) (DE-P). Thirty non-manipulated embryos (E) were transferred during the same period and served as controls. Pregnancies were diagnosed by rectal palpation 4-7 weeks after transfer. The pregnancy rates for DE-S, DE-P and E were 32%, 53% and 40%, respectively (P greater than 0.05). A substantial number of abortions were recorded between 50 and 250 days of pregnancy among the recipients with DE-S. The fetal survival rate for DE-S was reduced to 21% and significantly lower (p less than 0.05) than the survival rates of DE-P (43%) and E (40%). The quality of DE and the presence of ZP did not significantly influence the results. No conclusive reasons for the fetal loss could be found but different possibilities are discussed.

Animals↗
PubMed1991

Allergens in Hymenoptera venoms. XXIII. Venom content of imported fire ant whole body extracts.

A two-site immunoassay using monoclonal antibodies has been developed to measure the imported fire ant venom allergen Sol i III. The assay is specific for Solenopsis invicta venom, since one of the monoclonal antibodies does not react with Sol r III. A commercial imported fire ant whole body extract, known from RAST and skin test data to be potent, was found to contain 10.3 micrograms of Sol i III per milliliter. This was comparable to the content of an extract freshly prepared in our laboratory. The immunoassay detected Sol i III in an extract of fire ant abdomens, but not in head and thorax extract. The amount of imported fire ant venom in a potent whole body extract appears to be sufficient to provide possible protection for patients receiving it as immunotherapy, although this can only be verified by controlled clinical trials with intentional sting challenges.

Allergens↗
PubMed1991

Comparative evaluation of an ELISA based on recombinant polypeptides and IFA for serology of malaria.

In the present investigation we compare the performance of a solid-phase assay based on three recombinant polypeptides corresponding to three asexual blood-stage antigens of P. falciparum (ELISA MIXT) with the reference method for the measurement of antimalaria antibodies: indirect immunofluorescence antibody assay (IFA). Sera collected from persons with various degrees of exposure to malaria were selected: sera from inhabitants of a malaria endemic area (Group I), European patients with acute malaria infection (Group II) and blood donors with clinical symptoms of sickness or fever during a stay in malaria endemic areas. 86% of the sera gave concording results by ELISA MIXT and IFA. The correlation was 100% for sera of Group I but discrepancies were observed for Groups II and III. The great majority of the differences were due to sera positive on ELISA MIXT but not by IFA. Most of the sera positive on ELISA MIXT reacted with parasite-derived components only on Western-blot. These results underline the potential of the ELISA MIXT for epidemiologic studies.

Adolescent↗
PubMed1990

[Inoculation failure following hepatitis B vaccination. The effect of additional vaccinations].

One to three repeat vaccinations were undertaken in 63 persons (32 males, 31 females; mean age 29 [17-59] years) who had not or inadequately responded to basal immunization with hepatitis B vaccine (47 non- and 16 hyporesponders). After re-vaccination, 12 of the 47 nonresponders and 11 of 16 hyporesponders formed specific antibodies against hepatitis B surface antigen, anti-HBs, at concentrations above 10 IU/l. Six of 14 persons who had not responded to the first repeat vaccination reached anti-HBs concentrations above 10 U/l after a further injection. Vaccination response was age-dependent. The median age of those subjects who responded to the first re-vaccination was 27 (19-45) years, while the non-responders' median age was 34 (22-59) years (P less than 0.05). Re-vaccination also raised initially low anti-HBs values. These results indicate that some of the nonresponders can obtain reliable protection by revaccination(s).

Adolescent↗
PubMed1990

[Contaminated small bowel syndrome in infants caused by gram-negative bacteria and yeasts].

The upper small intestine is usually "sterile" in a healthy individuals, but due to some reasons the number of microorganisms may reach or increase above 10(4)/ml, leading to the contamination of the small intestine, which may cause severe malabsorption. The authors have diagnosed this syndrome in 50 children, aged between 1 month and 3 years, using breath hydrogen test and duodenal juice culture. Most of these children had growth retardation. According to their experience the authors found that the oral antibiotic is the effective treatment of this syndrome.

Anti-Bacterial Agents↗
PubMed1990

Specificity and inhibitory activity of antibodies to Plasmodium falciparum aldolase.

The multiplication of Plasmodium falciparum within RBC is energy-dependent and the glucose consumption of infected RBC is increased more than 50 times over the consumption of normal RBC. High levels of glycolytic enzymes such as fructose-1,6-diphosphate aldolase (p41) have been detected in infected RBC. Expression of the cloned aldolase gene of P. falciparum in Escherichia coli resulted in an enzymatically active polypeptide with a high sp. act. and the recombinant p41 aldolase was used for enzymatic and immunologic studies reported here. The presence of antibodies against p41 in the sera of human adults partially immune to malaria and immunization experiments in monkeys suggest that p41 is implicated in protective immune response against the parasite. Therefore, we analyzed the capacity of various antisera to inhibit P. falciparum aldolase activity. It was found that anti-p41 antibodies raised in mice, rabbits, and monkeys inhibited very efficiently aldolase activity in vitro up to dilutions higher than 10(-3). In contrast none of the human sera with high levels of anti-p41 antibodies were able to inhibit parasite aldolase activity even at a dilution of 1/2. The inability of human antisera to neutralize parasite aldolase is not related to antibody titers but is probably related to the specificity of the human antibodies. This finding is discussed in relation to homology of structure of P. falciparum and mammalian aldolase and to a possible mechanism of parasite adaptation and survival in its natural host.

Animals↗
PubMed1990

Trends in endometrial cancer incidence and mortality in Sweden, 1960-84.

Trends in incidence of and mortality from invasive endometrial cancer in Sweden in 1960-84 were analyzed. The study was based on virtually all 20,371 patients given this diagnosis and 4,887 patients who died of the disease in that period. Only minor changes occurred in age-standardized incidence in pre-menopausal women, in whom the rates declined consistently during the last 15 years, especially in the youngest age groups. Among post-menopausal women, an early increase was followed by stable rates in women over 60 and decreasing rates at ages 50-59 years. In contrast, mortality rates decreased consistently over the study period. Multivariate regression analyses indicated that birth cohort was a more important determinant of incidence and mortality than was time period. The relative risk of developing endometrial cancer increased by about 20 percent in women born around 1900 as compared with 1880, and by an additional 40 percent from the 1910 cohort to the maximum risk attained in those born around 1930. In successively younger birth cohorts, the risk markedly and continuously declined. These strong birth-cohort effects after 1910 may be reasonably explained by the change from the risk-increasing estrogen-only replacement therapy introduced in the 1960s to the less harmful use, starting about 10 years later, of combined estrogen-progestogen regimens; and further, by the protective exposure of a large proportion of pre-menopausal women to oral contraceptives. Mortality, however, decreased steadily in successive cohorts from those born in 1890, indicating that the increase in incidence was referable mainly to non-lethal cancers.

Aged↗
PubMed1990

Unusual X chromosome inactivation in a mentally retarded girl with an interstitial deletion Xq27: implications for the fragile X syndrome.

A de novo interstitial deletion (X)(q27.1q27.3), between the loci DXS 105 and F8, has been found in a mentally retarded female. The deleted X chromosome is preferentially early replicating in fibroblasts, B cells and T cells, suggesting that the missing region plays a role in inactivation of the X chromosome. None of the available DNA probes except DXS 98 maps to the deleted region of about 10,000 kb. The locus FRAXA is either included in the deletion, or located close to the distal break point.

Blotting, Southern↗