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Biomedical subjects

H Hauser

Publications and source records attributed to H Hauser.

At least 217 records · Page 12Linked to original sources
PubMed1985

Influence of a prolonged treatment with disulfiram and D-penicillamine on nitrosodiethylamine-induced biological and biochemical effects. II. Investigations on trace elements in the liver.

The influence of a 28-week treatment with disulfiram (DSF), D-penicillamine (PA), and nitrosodiethylamine (NDEA), as well as with a combination of DSF or PA with NDEA on the concentrations of eight essential trace elements in the whole liver tissue of rats was measured by means of neutron activation analysis. While NDEA treatment lowered the Zn content of the liver, DSF alone or in combination with NDEA enhanced the Zn and Se concentration by 50%-80%. Co, Cu, and Cd levels were increased by factors of 10, 60, and 110, respectively. The Mo concentration was decreased by 50% after DSF administration. PA reduced Cu, Co, and Zn in the liver. PA/NDEA treatment also lowered Cu, Co, and Zn content, but there was no strengthening effect of PA on the decrease in Zn observed with NDEA. The change of trace element concentrations, especially of Cu, is discussed with regard to the observed tumor induction in the liver, which tended to be increased by a combined NDEA/PA administration compared with NDEA treatment alone, whereas a protective action of DSF against NDEA induced liver tumors could not be established.

Animals↗
PubMed1985

Lever pressing for pups: evidence for hormonal influence upon maternal behavior of mice.

Five experiments were performed to determine the extent to which hormones influence maternal behavior of the female mouse. The number of pup-reinforced lever presses served as the measure of maternal behavior. In Experiment 1 it was found that postpartum mice performed significantly more pup-reinforced lever presses than intact or ovariectomized virgins. The second experiment showed that the augmentation of responding was unique to the postpartum period since responding was not facilitated during the last three days of pregnancy. Experiment 3 established that the postpartum augmentation of responding was mediated by the termination of pregnancy and not by parturition per se. It also was observed that the earlier during gestation pregnancy was terminated the greater the decline in response rate. Experiment 4 proved that ovarian secretions play a critical role in the pregnancy-terminated facilitation of pup-reinforced lever pressing. The final experiment demonstrated that the termination-of-pregnancy effect on responding in all likelihood is mediated by the synergistic actions of estrogen stimulation and progesterone withdrawal. The results show that the maternal behavior of the mouse, like that of the rat, is responsive to hormonal stimulation.

Animals↗
PubMed1985

Isolation of a functional human interleukin 2 gene from a cosmid library by recombination in vivo.

A method has been developed that allows the isolation of genomic clones from a cosmid library by homologous recombination in vivo. This method was used to isolate a human genomic interleukin 2 (IL2) gene. The genomic cosmid library was packaged in vivo into lambda phage particles. A recombination-proficient host strain carrying IL2 cDNA sequences in a non-homologous plasmid vector was infected by the packaged cosmid library. After in vivo packaging and reinfection, recombinants carrying the antibiotic resistance genes of both vectors were selected. From a recombinant cosmid clone the chromosomal IL2 gene was restored. After DNA mediated gene transfer into mouse Ltk- cells human IL2 was expressed constitutively.

Animals↗
PubMed1985

Contribution of paramagnetic trace elements to the spin-lattice relaxation time in the liver.

The relaxation times of water protons in rat liver tissue were measured with a NMR spectrometer at 20 MHz. The paramagnetic trace elements Cu, Fe, and Mn were determined by neutron activation analysis. No shortening of T1 could be observed when liver Cu or Fe concentration was increased in the microgram range. T1 was strongly correlated with the liver Mn concentration of untreated animals and animals whose liver Mn concentration was artificially increased or decreased by intravenous injection of manganous acetate or a metal chelating agent with high affinity for hepatobiliary excretion. Deviations from this Mn-T1 correlation were found in the initial phase of liver cirrhosis induced by thioacetamide (elongated T1, normal Mn concentration) and after stimulation of liver growth by phenobarbital (normal T1, decreased Mn concentration). An increased or decreased enhancement factor for Mn may have contributed to the observed deviations during phenobarbital and thioacetamide treatment.

Animals↗
PubMed1985

Production of human interferon-beta in mouse L-cells.

A mouse fibroblast cell-constructed by genetic engineering--expresses glycosylated human interferon-beta constitutively. The cells were cultivated on microcarriers in special bioreactors. Under these conditions they produce a maximum yield of 6 000 units interferon-beta/ml/day at cell densities of about 2,2 X 10(6) cells/ml. The production stage of interferon-beta is longer than one month.

Animals↗
PubMed1984

Leakiness of brush-border vesicles.

From the water content of pelleted brush-border vesicles and from a comparison of the aqueous volume within the pellet that is available to [3H]inulin (58%), inulin [14C]carboxylic acid (34%, both approx. 5000 daltons), [3H]raffinose (97%, 540 daltons) and [3H]glucose (94%, 180 daltons) it is concluded that only 1 in 4 to 6 of the brush-border vesicles is sealed. The implication of this finding for labelling and transport studies and for vesicle formation is discussed.

Animals↗
PubMed1984

Interactions of divalent cations with phosphatidylserine bilayer membranes.

The interaction of divalent cations with a homologous series of diacylphosphatidylserines (diacyl-PS) has been studied by differential scanning calorimetry and X-ray diffraction. Hydrated di-C14-PS (DMPS) exhibits a gel leads to liquid-crystal bilayer transition at 39 degrees C (delta H = 7.2 kcal/mol of DMPS). With increasing MgCl2 concentration, progressive conversion to a phase exhibiting a high melting (98 degrees C), high enthalpy (delta H congruent to 11.0 kcal/mol of DMPS) transition is observed. Similar behavior is observed for DMPS with increasing CaCl2 concentration. In this case, the high-temperature transition of the Ca2+-DMPS complex occurs at approximately 155 degrees C and is immediately followed by an exothermic transition probably associated with PS decomposition. For di-C12-, di-C14-, di-C16- (DPPS), and di-C18-PS, the transition temperatures of the Ca2+-PS complexes are in the range 151-155 degrees C; only di-C10-PS exhibits a significantly lower value, 142 degrees C. A different pattern of behavior is exhibited by DPPS in the presence of Sr2+ or Ba2+, with transitions in the range 70-80 degrees C being observed. X-ray diffraction of the Ca2+-PS complexes at 20 degrees C provides evidence of structural homology. All Ca2+-PS complexes exhibit bilayer structures, the bilayer periodicity increasing linearly from 35.0 A for di-C10-PS to 52.5 A for di-C18-PS. Wide-angle X-ray diffraction data indicate that hydrocarbon chain "crystallization" occurs on Ca2+-PS complex formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Calorimetry, Differential Scanning↗
PubMed1983

Order-disorder phase transition and lipid dynamics in rabbit small intestinal brush border membranes. Effect of proteins.

The total lipids extracted from brush border membranes form smectic lamellar phases when dispersed in water. 31P broad-band nuclear magnetic resonance (NMR) shows that between body temperature (37 degrees C) and freezing of the solvent, the extracted lipids form bilayers with the lipid molecules undergoing fast anisotropic motion. This is also true for the lipids present in the brush border membrane. The electron spin resonance (ESR) results obtained with various hydrophobic spin probes incorporated in either brush border vesicle membranes or their extracted lipids are consistent with this interpretation. By use of a variety of chemically different spin-labels, the temperature dependence of brush border membranes and their extracted lipids was probed. The temperature dependence of various ESR spectral parameters shows discontinuities that, by comparison with differential scanning calorimetry, are assigned to a lipid thermotropic phase transition. Differential scanning calorimetry shows that the lipid in brush border membranes undergoes a broad, reversible phase transition of low enthalpy between 10 and 30 degrees C, with a peak temperature of about 25 degrees C. Hence, the brush border membrane of rabbit small intestine functions in the liquid-crystalline state, well above the peak temperature and also above the upper limit of the lipid phase transition. Therefore, in itself, the thermotropic lipid phase transition is unlikely to play a physiological role. The low enthalpy of the lipid phase transition, indicative of a lack of cooperativity, is primarily attributed to the relatively high cholesterol content and to heterogeneity in the lipid composition of this membrane [Hauser, H., Howell, K., Dawson, R. M. C., & Bowyer, D. E. (1980) Biochim. Biophys. Acta 602, 567-577].(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Vesiculation of unsonicated phospholipid dispersions containing phosphatidic acid by pH adjustment: physicochemical properties of the resulting unilamellar vesicles.

Aqueous dispersions of phosphatidic acid and mixtures of phosphatidic acid with other phospholipids vesiculate when the pH is transiently increased to a pH near or above the second pK of the phosphatidic acid. Both small unilamellar vesicles (SUV) of a narrow size distribution (average diameter 25-30 nm) and large unilamellar vesicles (LUV) of a wide size distribution are formed. The fraction of SUV increases linearly with increasing pH from 6 to 12 and was also increased by increasing the rate of the pH change from 2 min to 1 s. For mixed phospholipid dispersions, the fraction of SUV appears to be linearly related to the phosphatidic acid content. Unilamellar vesicles formed by the transient pH increase are subsequently relatively stable to changes in pH and ionic strength. If, after vesiculation is induced, the dispersion (pH 7-8) is acidified to pH 3, the fraction of SUV decreases. However, the multilamellar structures present in the original dispersion do not re-form, and most of the reduction in the SUV fraction is reversible when the pH is returned to 7-8. The addition of NaCl to the dispersion after vesiculation has no effect on the fraction of SUV up to physiological NaCl concentrations. Subsequent addition of NaCl to a concentration in excess of 0.2 M reduces the SUV fraction; this disappears above 1 M NaCl due to aggregation or fusion. SUV of phosphatidic acid or mixed phospholipids containing phosphatidic acid can be stored at 4 degrees C for 14 days without detectable aggregation and/or fusion.

Freeze Fracturing↗
PubMed1983

Contiguity to males in utero affects avoidance responding in adult female mice.

Female mice that had been situated in utero between two female fetuses displayed higher levels of active avoidance responding in adult life than females that had been located between two male fetuses and males for whom uterine position was without effect. Uterine position, therefore, influences acquired as well as species-typical behaviors.

Androgens↗
PubMed1983

[Appendicular invagination and post-appendectomy invagination].

Intussusception of the appendix is an uncommon event (200 cases previously reported) and intussusception after appendicectomy is rare (20 cases previously published). Two recent cases are reported, the first with primary appendiceal intussusception and the second ileocolic intussusception after appendicectomy. In the second case the final pathology report revealed an intussuscepted caecal duplication responsible for the ileocolic intussusception. This event has not been previously reported. Symptomatology, investigation, classification, differential diagnosis and surgical tactics are discussed.

Adolescent↗
PubMed1983

DNA-mediated gene transfer in Friend leukemia cells by cotransfection of simian virus 40 DNA with herpes simplex virus thymidine kinase DNA.

Thymidine kinase-negative Friend leukemia cells were cotransfected with simian virus 40 (SV40) DNA and thymidine kinase gene DNA of herpes simplex virus type 1. The transfected thymidine kinase-positive cells were selected in HAT medium, and SV40 T-antigen expression was observed over many months in cells cultured under selective conditions, and after adaptation to normal growth medium under nonselective conditions. It was shown by Southern blot hybridization that SV40 DNA was integrated in multiple copies in the chromosomal DNA of several clones. All SV40 DNA-containing Friend leukemia cell clones analyzed were able to undergo induced erythroid differentiation. Induced cultures still expressed SV40 T-antigen to the same extent that untreated control cultures did.

Animals↗