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Biomedical subjects

U Müller

Publications and source records attributed to U Müller.

At least 559 records · Page 31Linked to original sources
PubMed1980

Serum-borne H-Y antigen in the fetal bovine freemartin.

In mammals, ovarian cells that have been exposed to soluble H-Y antigen acquire the H-Y+ cellular phenotype. They absorb H-Y antibody in serological tests. To determine whether masculinization of the bovine freemartin, the synchorial female twin of a bull, could be due to attachment of circulating bull-twin-derived H-Y in the freemartin gonad, we exposed normal fetal ovarian cells to serum from fetal bulls, fetal cows and fetal freemartins. Ovarian target cells became H-Y+ after exposure to serum from fetal bulls or fetal freemartins, but not after exposure to serum from fetal cows. In a new competitive binding radioassay, uptake of Daudi-secreted tritiated H-Y was inhibited in fetal ovarian target cells first exposed to mouse testis supernatant, a demonstrated source of soluble H-Y. It was also inhibited in ovarian target cells exposed to serum from fetal bulls or fetal freemartins; uptake was unaffected by exposure to serum from fetal cows. Since Daudi-secreted H-Y is known to induce precocious testicular organogenesis in XX indifferent gonads in culture, we infer that initial transformation of the freemartin gonad is due to H-Y antigen that is secreted in the fetal bull, transmitted in the common chorionic vasculature and bound by gonadal receptors of the fetal cow.

Animals↗
PubMed1980

[Genetic amniocentesis: technique and results in 1,000 first trimester amniocenteses (author's transl)].

The results of 1,000 transabdominal amniocenteses between 15 and 20 weeks gestation are reported. The method is described. The bio-chemical and cytogenetic results are reported. - Amniocentesis in the first trimester is not a routine investigation since fetal and maternal risks are associated with this procedure. The risk of abortion following amniocentesis was lowered from 6/1000 to 2/500 by improvement of the technique under ultra-sound control. The worst maternal complication observed was a septic abortion one day after amniocentesis. 96% of all cyto-genetic examinations showed normal karotypes. The largest group at risk were mothers over 35 years of age. In this group chromosome anomalies were found in 17 cases. All neural tube defects were found by determination of the alpha-fetoprotein in the amniotic fluid. 26 terminations of pregnancy for fetal indications were carried out. Two patients refused therapeutic abortions despite trisomy 21 for ethical reasons. One patient continues her pregnancy with a 47 XYZ pregnancy.

Abortion, Induced↗
PubMed1980

On the significance of severe local reactions to Hymenoptera stings.

Of 317 patients with hypersensitivity to Hymenoptera stings forty had severe local reactions (SLR) only, fifty-nine reported severe local reactions before their first and seven after their last systemic reaction (SR). The probability to develop a life threatening systemic reaction when restung after a severe local reaction was calculated to be about 5%. In 80% of the patients with severe local reactions only, hypersensitivity to either bee or yellow jacket venom could be demonstrated by skin tests and/or RAST. A fair correlation of skin test and RAST results was observed. In patients with severe local reactions hyposensitization therapy with venoms is not generally indicated. In exceptional patients whose allergy is proven by skin tests or RAST and who are at a high risk of being restung, hyposensitization may be considered.

Adolescent↗
PubMed1980

The effect of bromocriptine during early pregnancy in the rat: inhibition of implantation.

The increase in the number of the ovarian LH/hCG-receptors and of serum progesterone concentration during pregnancy in the rat is highly dependent on the presence of prolactin during the luteinization process. Blocking of the hypophyseal prolactin secretion by twice daily injections of 2 microgram/g body weight bromocriptine into rats from the first day of pregnancy onwards prevents the increase in ovarian hCG-binding and progesterone production. Similar results are obtained by application of bromocriptine during the first three days only or either at day 1, 3 or 5 after mating. In all bromocriptine treated rats implantation of blastocysts does not occur. The failure to implant is not due to a teratogenic effect of bromocriptine onto preimplantation embryos, but is probably the consequence of changes of the uterine mucosa caused by the lack of progesterone production in the luteal cells.

Animals↗
PubMed1980

Coexistence of nucleosomal and various non-nucleosomal chromatin configurations in cells infected with herpes simplex virus.

Coexistence of four different forms of chromatin was observed by electron microscopy in nuclear spread preparations of monkey kidney cells during late stages of infection with herpes simplex virus (HSV-1 AMG). Besides typical nucleosomal (i) chromatin, thin (3-5 nm) strands morphologically indistinguishable from protein-free DNA were frequent, without (ii) or with (iii) sparse 10-22 nm large granules different from nucleosomes. In addition, uniformly thick (mean 17 nm), heavily stained chromatin strands (iv) were seen. The non-nucleosomal character of types (iii) and (iv) chromatin was also demonstrated by their resistance to histone removal in Sarkosyl and heparin. All four forms were seen in capsid-associated HSV-DNA molecules, and various combinations of these forms occurred in adjacent regions of the same DNA molecule, including the vicinity of replication branch points. Especially frequent were regions of chromatin types (ii) or (iii) alternating with thickly coated intercepts of type (iv) chromatin, the latter often displaying "bubble"-like strand separations. The appearance of chromatin types (ii)-(iv) was dependent on viral replication. These chromatin arrays were compared with structures observed in purified HSV-DNA from these cells. Patterns of single-stranded regions were found in HSV-DNA that were similar to those observed in the thickly coated type (iv) chromatin. It is concluded that, in these nuclei, non-nucleosomal arrangements can be formed, at least on viral DNA, under conditions of continued DNA synthesis and inhibited protein synthesis, and that single-stranded DNA is packed into a characteristic thick strand of non-nucleosomal chromatin by association with a special, probably virus-coded protein.

Animals↗
PubMed1980

Supranucleosomal organization of sea urchin sperm chromatin in regularly arranged 40 to 50 nm large granular subunits.

The organization of the chromatin of sperm nuclei of sea urchin (Parcentrotus lividus and Sphaerechinus granularis) was studied by electron microscopy using thin sections of fixed cells and spread preparations of chromatin obtained after various procedures involving incubation in low salt buffers. In fixed cells and in moderately dispersed preparations chromatin appeared in the form of fibrillar chains formed by closely apposed, distinctly sized granules that were larger than chromatin subunit structures so far described in other kinds of chromatin (mean diameters of particle units determined were 36 nm, in thin sections, and 47 nm, in spread preparations). Upon prolonged incubation in low salt buffer an increasing number of these large granular units was transformed into extended nucleosomal chains (nucleofilaments). Estimations indicated that the large granules contained 20 to 26 nucleosomes, i.e. 4.8 to 6.2 kb DNA, resulting in a linear DNA contraction ratio of 33 to 55, which is in a similar range as values reported for the supranucleosomal chromatin particle of the SV40 minichromosome but greater than contraction ratios of "superbead" structures. The unravelling of the large supranucleosomal granule into the extended nucleofilament chain in low salt buffers seemed to be a gradual process since intermediate stages of variable particles sizes and shapes were observed. This novel type of chromatin particle is considered to represent an example of a naturally occurring globular supranucleosomal packing unit of chromatin which is predominating, if not the only forms of supranucleosomal levels of chromatin organization and in relation to the special DNA content and histone composition of sea urchin sperm nucleosomes.

Animals↗
PubMed1980

Reversible in vitro packing of nucleosomal filaments into globular supranucleosomal units in chromatin of whole chick erythrocyte nuclei.

Structural transitions between extended and condensed forms of chromatin have been studied by electron microscopy of whole chicken erythrocyte nuclei incubated in low buffer concentrations (0.5 mM sodium borate; 1 to 5 mM Tris-HCl) with and without additions of monovalent or divalent cations. Both spread preparations and ultrathin sections have been examined. It is shown that the condensed chromatin present in chicken erythrocytes is organized, at the supranucleosomal level, in granular particles (mean diameter 29 +/- 3 nM0 tightly apposed against each other in beaded chains (higher order fibrils). These chains of higher order granules are gradually unravelled in low salt buffers lacking divalent cations into extended nucleosomal filaments. When nuclear chromatin swollen in low salt buffer and extended uniformly into nucleosomal filaments is exposed to buffers containing higher concentrations of monovalent ions (e.g., 100 mM NaCl) or low concentrations of divalent cations (e.g., 0.05-0.5 mM MgCl2) rapid and almost complete recondensation of the entire chromatin of a nucleus into one compact spheroidal aggregate of chains of higher order granules (diameters 25-30 nm) is observed. This transition is reversible and whole nuclear chromatin can be induced, in vitro, to undergo several cycles of such conformational changes. The results show that reconstitution of globular forms of higher order packing of nucleosomes is not restricted to oligonucleosomal units but also takes place, in a rather uniform and regular mode, in long nucleosomal filaments as they are present in whole nuclei. The data are discussed in relation to other studies of chromatin ultrastructure and are interpreted to indicate that the predominant, if not exclusive form of supranucleosomal packing existing in condensed inactive chromatin of living cells is a chromatin fibril made up of serially arranged, close-packed granular particles ("suprabeads" sensu in [64]). In addition, the results suggest that higher order packing of chromatin into such supranucleosomal granules is not simply a function of ionic strength but that the type of ions present strongly influences the state of chromatin packing.

Animals↗
PubMed1979

A highly sensitive peroxidase-antiperoxidase method for detection of H-Y antigen on cultivated human fibroblasts.

A peroxidase-anti-perioxidase method for the detection of H-Y antigen at the single cell level is described. The efficiency of the test was examined in cultivated fibroblasts derived from control subjects and from XX males and a true hermaphrodite. For comparison, H-Y antigen was determined in blood cells of the same probands using the cytotoxic test. The finding of H-Y positive fibroblasts in the intersex patients has implications for the origin of these disorders.

Cells, Cultured↗
PubMed1979

Neuromyopathy during chronic amiodarone treatment. A case report.

Clinical, electrophysiological, and the nerve and muscle biopsy findings from a case treated with amiodarone are reported. Marked distal motor and sensory impairment and distal muscular atrophy were observed clinically. The electrophysiological examination revealed normal motor and sensory conduction velocities in the median nerve; the sensory action potentials were polyphasic and reduced in amplitude. Electromyography revealed denervation potentials and severe loss of motor units in the M. extensor digitorum brevis and in the M. tibialis anterior. The light and electronmicroscopical study of a N. suralis biopsy displayed total loss of large myelinated fibers and an almost total reduction of small myelinated fibers. The number of unmyelinated axons was markedly reduced. Fibrocytes and degenerative axons polymorphous inclusion bodies were present in Schwann cells. The muscle biopsy revealed both neurogenic and myopathic changes. Lipid storage was also present in the muscle fibers. Physical and chemical analysis of the nerve and muscle biopsy revealed the content of iodine to be more than 40 times increased. The findings indicate damage of axons, schwann cells and muscle fibers. It is suggested that the lipid storage in nerve and muscle tissue might be related to the accumulation of the drug or its metabolites.

Aged↗