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Biomedical subjects

T Braun

Publications and source records attributed to T Braun.

At least 127 records · Page 7Linked to original sources
PubMed1987

Clonidine and prazosin block the iminodipropionitrile (IDPN)-induced spasmodic dyskinetic syndrome in mice.

The effects of drugs with selective action on alpha 1- or alpha 2-adrenoceptors were investigated on persistent head twitches, vertical neck dyskinesia, and the random circling behaviors induced by chronic intraperitoneal injections of IDPN. The alpha agonist clonidine and the alpha antagonist prazosin inhibited the IDPN-induced behavioral syndrome whereas the alpha antagonist yohimbine had no significant effect. These results suggest that dysregulation of a facilitatory noradrenergic input to cortical and/or subcortical motor areas may be involved in the abnormal movements caused by chronic treatment with IDPN.

Animals↗
PubMed1987

Human mitochondrial aldehyde dehydrogenase: mRNA expression in different tissues using a specific probe isolated from a cDNA expression library.

Using monospecific antibodies against mitochondrial aldehyde dehydrogenase (ALDH I), cDNA clones were isolated from a human liver cDNA library constructed in the plasmid expression vector pEX. Two overlapping clones pEXAL21 and pEXAL43 containing inserts of 861 bp and 1180 bp respectively, code for the carboxy-terminal end of ALDH I as confirmed by sequence analysis. The messenger RNA of ALDH I was estimated by Northern blot analysis to contain approximately 2350 nucleotides. RNA hybridizations revealed that the ALDH I gene transcription is generally low in fetal tissues. Especially, transcription in the adult liver is up to 5-fold higher than in the fetal liver.

Adult↗
PubMed1986

Charting the trends in nuclear techniques for analysis of inorganic environmental pollutants.

Publications in analytical abstracts in the period 1975-1984 and papers presented at the Modern Trends in Activation Analysis international conferences series in the period 1961-1986 have been used as an empirical basis for assessing general trends in research and publication activity. Some ebbs and flows in the specialty of instrumental techniques for analysis of environmental trace pollutants are revealed by a statistical analysis of the publications.

Activation Analysis↗
PubMed1986

Comparison of alternating to nonalternating chemotherapy regimens for non-small cell lung cancer.

Forty-seven patients with stage III lung cancer from four institutions in the Denver area were entered in a study comparing two regimens of chemotherapy. The patients were randomized into two groups: Group A received lomustine, cyclophosphamide, vincristine, cisplatin, and doxorubicin monthly; Group B received the five-drug regimen on Months 1, 3, and 5 and received 5-FU by constant infusion, methotrexate, and mitomycin on Months 2, 4, and 6. The age, extent of disease, Karnofsky score, prior therapy, and average number of chemotherapy courses received in each group were comparable. The median survival in Group A was 265 days and in Group B was 163 days (P greater than 0.25). There does not seem to be an advantage in survival in patients who are treated with the eight-drug regimen over the five-drug regimen.

Adenocarcinoma↗
PubMed1984

Radiochemistry and biostability of autologous leucocytes labelled with 99mTc-stannous colloid in whole blood.

Autologous leucocytes were labelled in whole blood by phagocytic uptake of 99mTc-stannous colloid. This colloid has a mean particle size of 1.5 micron and labels leucocytes with 81% efficiency. Individual cell uptakes were: granulocytes 42%, monocytes 39%. Isotonic sodium citrate added after the labelling procedure did solubilise excess colloid but was not necessary for adequate removal of excess colloid. Labelled leucocytes were shown in vitro to be viable and maintain normal bactericidal and chemotactic capacity. Biodistribution, clearance rates and dosimetry are presented. These results indicate that autologous leucocytes can be efficiently labelled with 99mTc-stannous colloid with good residual cell function.

Animals↗
PubMed1981

FSH and testosterone effects in seminiferous tubules of immature hypophysectomized rats.

The effects of follicle-stimulating hormone (FSH) and testosterone on the development of the cytosolic germ cell adenylate cyclase and germ cell morphology in rats hypophysectomized at 29 days of age were studied. Following hypophysectomy, the adenylate cyclase content fell to marginal levels and germ cell development ceased at the late pachytene stage. Testosterone treatment led to a moderate increase in the cytosolic enzyme content and to progression of spermatid cell development to stages 8-12. FSH treatment with doses of 80-100 micrograms/day restored enzyme content to levels seen in control rats, as well as progression of germ cell development up to stages 15-16, i.e., to the same stages present in age-matched control (sham-operated) rats. The results indicate that in immature rats FSH is essential for spermatid cell maturation as is evidenced by its ability to stimulate the formation of cytosolic germ cell adenylate cyclase to quantitatively normal levels, as well as to stimulate the development of spermatid cells.

Adenylyl Cyclases↗
PubMed1977

Mn2+-sensitive, soluble adenylate cyclase in rat testis. Differentiation from other testicular nucleotide cyclases.

In subcellular fractions prepared from homogenate of adult rat testis adenylate cyclase (ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1) activity was found in the particulate, primarily 600 X g for 10 min, fractions, as well as in the cytosol. The properties of the adenylate cyclase in the cytosol differs substantially from the adenylate cyclase system associated with the 600 X g for 10 min particulate fraction. The cytosol enzyme, in contrast to the particulate adenylate cyclase, was found to be fluoride- and gonadotropin hormone-insensitive. The cytosol adenylate cyclase appears to be located in the germ cell while the particulate enzyme system in the non-germ cell component of the seminiferous tubules, The cytosol adenylate cyclase was found to be distinct also from the guanylate cyclase present in the rat testis cytosol. The adenylate cyclase appears to be located in the germ cell component while the guanylate cyclase, in the non-germ cell tubular component. Furthermore, it was found that the cytosol guanylate cyclase develops at an earlier stage of spermatogenesis, and precedes the development of the cytosol adenylate cyclase.

Adenylyl Cyclases↗
PubMed1977

[Classification of periodontologically indicated vestibuloplasties].

The present paper deals with periodontologically indicated vestibule deepenings. For the first time, a grouping of the vestibule deepenings has been elaborated that comprises all fundamental possibilities of plastic-surgical intervention. This grouping gives a survey and a classification of the different methods of operation (in part designated by the names of the respective authors) and permits to trace back many methods to a fundamental principle whereby the number of seemingly different techniques of operation is reduced.

Alveolar Process↗
PubMed1976

LH- and FSH-stimulating of adenylate cyclase in seminiferous tubules from young rats: functional FSH and LH receptors unmasked by homogenization.

LH- and FSH-sensitive adenylate cyclase activity was present in homogenates of whole testis tissue as well as in microdissected seminiferous tubules derived from young rats. In homogenates of seminiferous tubules a single adenylate cyclase appears to interact with both LH and FSH through separate hormone-specific receptors. Disruption of testis tissue by homogenization exposes functional FSH and LH receptors which are inaccessible to the hormones in intact cell preparations. These results indicate that in certain seminiferous tubule cell types only a fraction of the total functional receptors present is accessible to the cell surface for interaction with hormone.

Adenylyl Cyclases↗
PubMed1975

Development of a Mn-2+-sensitive, "soluble" adenylate cyclase in rat testis.

A distinctive Mn-2+-sensitive adenylate cyclase [ATP pyrophosphate-lyase(cyclizing), EC 4.6.1.1] system insensitive to fluoride has been found in rat seminiferous tubules and epididymal sperm. The development of this distinctive adenylate cyclase in testis was studied during spermatogenesis. It was first detectable in seminiferous tubules in immature rats at about the time of the first reductive divisions and the appearance of spermatid cells. The specific activity of the enzyme increased substantially during the period of spermatogenesis when spermatids develop into mature spermatozoa, and reached maximal values in the testis of adult rats. After centrifugation of testis tissue homogenates at 105,000 X g for 60 min, the Mn-2+-sensitive adenylate cyclase activity was found in the cytosol. The enzyme remains in solution after centrifugation at 300,000 X g for 5 hr or at 180,000 X g for 24 hr and passes through a 0.22 mum Millipore filter. Electron microscopic examination showed no visible membrane fragments or vesicles in the filtered supernatant. The Mn-2+-sensitive adenylate cyclase system is also present in epidiymal sperm. However, in the sperm obtained from either the caput or the cauda of epididymis, the adenylate cyclase is membrane-associated and found in particulate fractions of sperm homogenates. It therefore appears that the Mn-2+-sensitive adenylate cyclase is initially present in the cytoplasm either unattached or loosely bound to intracellular membranes and becomes firmly attached to sperm membranes later in development. This occurs either during the process of maturation of spermatids into sperm or during the transport of the testicular sperm into the epididymis.

Adenylyl Cyclases↗
PubMed1975

The effect of divalent cations on bovine spermatozoal adenylate cyclase activity.

The effect of divalent cations on bovine sperm adenylate cyclase activity was studied. Mn2+, Co2+, Cd2+, Zn2+, Mg2+ and Ca2+ were found to satisfy the divalent cation requirement for catalysis of the bovine sperm adenylate cyclase. These divalent cations in excess of the amount necessary for the formation of the metal-ATP substrate complex were found to stimulate the enzyme activity to various degrees. The magnitude of stimulation at saturating concentrations of the divalent cations was strikingly greater with M2+ than with either Ca2+, Mg2+, Zn2+, Cd2+ or Co2+. The apparent Km was lowest for Zm2+ (0.1 - 0.2 mM) than for any of the other divalent cations tested (1.2 - 2.3 mM). The enzyme stimulation by Mn2+ was decreased by the simultaneous addition of Co2+, Cd2+, Ni2+ and particularly Zn2+ and Cu2+. The antagonism between Mn2+ and Cu2+ or Zn2+ appeared to have both competitive and non-competitive features. The inhibitory effect of Cu2+ on Mn2+-stimulated adenylate cyclase activity was prevented by 2,3-dimercaptopropanol, but not by dithiothreitol, L-ergothioneine, EDTA, EGTA or D-penicillamine. Ca2+ at concentrations of 1-5 mM was found to act synergistically with Mg2+, Zn2+, Co2+ and Mn2+ in stimulating sperm adenylate cyclase activity. The Ca2+ augmentation of the stimulatory effect of Zn2+, Co2+, Mg2+ and Mn2+ appeared to be specific.

Adenylyl Cyclases↗