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Biomedical subjects

H Müller

Publications and source records attributed to H Müller.

At least 451 records · Page 25Linked to original sources
PubMed1990

Immunological characterization and localization of the Na+/Ca2(+)-exchanger in bovine retina.

The sodium/calcium exchanger was purified from bovine retinal rod outer segment membranes and used for the immunization of New Zealand White rabbits. A polyclonal antibody was produced which was found to bind specifically to the 230 kDa Na+/Ca2(+)-exchanger protein as assessed by Western blotting. The antibody did not bind to the high-molecular-weight "rim protein," thereby demonstrating that this protein is distinct from the rod outer segment of Na+/Ca2(+)-exchanger. We used the polyclonal antibody for immunohistochemically localizing the exchange protein in bovine retina. Fluorescent light microscopy revealed intensive immunolabeling of the photoreceptor outer segments, whereas other retinal cell layers exhibited minimal binding. Using the electron microscopic immunogold method, we found specific antibody binding to the extracellular side of rod outer segment plasma membrane. Rod disk membranes, rod inner segments, and cone photoreceptors displayed no significant labeling. We therefore conclude that the Na+/Ca2(+)-exchanger is localized primarily in the rod outer segment plasma membrane, the most appropriate localization considering its proposed role in the process of vertebrate phototransduction.

Animals↗
PubMed1990

[The genesis of permanent growth of the beak wattle of a wattle-type pigeon].

Variation in size of warts located on the beak of wattle-pigeons represents a dominant trait of this breed. Excessive growth to extraordinary size in two breeds (barbs and carriers), in addition to a large beak, can cause losses due to the inability of the parents to feed the offspring properly. In older birds, respiration is impeded and the field of vision is limited. This permanent growth in barbs and carriers could not be attributed neither to an infection with papovaviruses, nor to the overexpression of the retroviral c-src-protooncogen. This finding, in conjunction with the genetic analysis, underlines that this prominent trait is genetically determined.

Animals↗
PubMed1990

[Perioperative preventive antibiotic treatment with fosfomycin in heart surgery: serum kinetics in extracorporeal circulation and determination of concentration in heart valve tissue].

A prospective clinical study was carried out to assess the adequacy of perioperative antibiotic prophylaxis using fosfomycin in patients undergoing open-heart surgery for valve diseases for the prevention of early postoperative endocarditis, as well as for serious mediastinal infections that are caused mostly by multiresistant staphylococci and Gram-negative bacteria. Perioperative pharmacokinetics and tissue penetration were determined within the harvested heart valves and subcutaneous tissue. Reliable bactericidal serum levels were established at the first measurement 10 min after the end of intravenous infusion (203.7 +/- 44.7 micrograms/ml) and were maintained during surgery for at least 120 min (124.6 +/- 58.4 micrograms/ml), even in cases of prolonged extracorporeal circulation. Cardiopulmonary bypass did not alter the serum elimination of fosfomycin in comparison with patients not undergoing extracorporeal circulation. Peak tissue concentrations were achieved in both aortic and mitral valves after 30 min, ranging between 27.1 and 76.9 micrograms/g for aortic valves and 39.6-69.4 micrograms/g for mitral valves, depending on the degree of valvular degeneration. MIC values of 16 micrograms/g were maintained in both valves for at least up to 60 min. There was no evidence of renal impairment, adverse reactions or infections during the postoperative course or thereafter for a period of 3 months. It is concluded that perioperative intravenous antibiotic prophylaxis using fosfomycin (5 g t.i.d. in adults), beginning with induction of anesthesia and continued for 48 h postoperatively, provides rapid, reliable bactericidal serum levels and valvular tissue concentrations that will inhibit most Gram-positive and Gram-negative organisms that cause bacterial endocarditis and other serious infections following cardiac surgery.

Aged↗
PubMed1990

[Effects of adjuvant chemotherapy of breast cancer on gonadal function].

Premenopausal breast cancer patients frequently develop amenorrhea during adjuvant chemotherapy. Despite psychic distress and severe weight loss are possible causes for secondary amenorrhea in cancer patients, it is in this case due to the gonadotoxicity of the cytostatic drugs. Alkylating agents, such as cyclophosphamide, damage ovaries directly, resulting in ovarian fibrosis, atretic follicles and decline in estrogen production. Elevated plasma levels of LH and FSH show adequate reaction of the hypothalamohypophyseal unit. There is no change in the androgen production of stromal cells as well as in the plasma levels of prolactin and adrenal androgen precursors. Ovarian damage goes along with hot flushes, loss of libido and dyspareunia. The onset of amenorrhea is age- and dose-related. Commonly the changes are irreversible. Estrogen replacement therapy promptly removes menopausal symptoms but is contra-indicated regarding the possible hormone-dependence of the tumor. In this case low dose medroxy-progesterone acetate is indicated.

Amenorrhea↗
PubMed1990

[The effects of local anesthesia on the thermoregulation of the tooth pulp].

Laser Doppler flowmetry was used to measure the effects of local anesthesia on the thermoregulation of the tooth pulp. Heat affecting the pulp is physiologically offset by a reactive increase in blood flow. An increase in temperature from 35 degrees C to 45 degrees C results in an increase in blood flow by 100%, on an average. Local anesthetics produce a reversible block of this protective mechanism, thus eliminating more or less the reactive increase in blood flow. Under local anesthesia the defence power of the tooth pulp against noxious temperatures seems to be considerably reduced.

Anesthesia, Local↗
PubMed1990

[Intraoperative suppression of spasticity using intrathecal baclofen].

Even in patients with complete loss of sensation and paraplegia after cervical spinal trauma, abdominal operations usually require general or spinal anesthesia due to spasms and increased muscle tone. Both anesthetic types have serious drawbacks under these circumstances, e.g. hyperkalemia induced by relaxation or the impossibility of adequate monitoring of the level of spinal blockade. After an onset time of 1-2 h the intrathecal injection of approx. 100 micrograms baclofen, a spinally acting GABAB-agonist, led to complete and long-lasting suppression of surgically induced spasticity. This could be demonstrated by neurological examination (spasticity scores: Ashworth score, spasm score, clonus score) during 5 neurosurgical operations in 3 patients with paraplegia. Except for slight sedation, the patients had no discomfort during operation. Intrathecal baclofen was also effective against autonomic hyperreflexia, i.e. vegetative dysregulation such as bradycardia or hypertension, provoked by catheterization or bladder surgery.

Adult↗
PubMed1990

[Cryopreservation of bovine embryos].

The method of cryopreservation of embryos aged seven days, proposed for embryo transfer with cattle by Niemann (1985), was tested under production conditions on three cattle breeding farms and three experimental animal units. The number of donors was 128, and 467 intact embryos were obtained from them and were cryopreserved in semen straw. Following thawing, 455 were recovered, and 439 (96.5 percent) of these were suitable for transfer. A pregnancy rate of 49.0 percent was recorded from 412 transfers. This rate was differentiated by oestric cycle conditions of heifer recipients, which gave percentages of 46.0 among recipients of seven-day old embryos, 45.7 for eight-day recipients, and 65.8 for six-day recipients. Related to pregnancy results recorded on the same units from transfer of freshly collected seven-day embryos, the efficiency coefficient was 0.69 (550 fresh transfers = 65.4 percent and 222 cryopreserved transfers = 48.2 percent). The method is recommended for general field practice.

Animals↗
PubMed1990

[Prospective study of primary and secondary prevention of Pneumocystis carinii pneumonia with pentamidine aerosol].

In an open prospective study in the AIDS Outpatient Department of the Frankfurt University Clinic the efficacy of pentamidine aerosol at a dosage of 200 mg every 14 days in the primary and secondary prophylaxis of pneumocystis carinii pneumonia was tested. The incidence of pneumocystis carinii pneumonia was reduced by more than 75% in the group of patients receiving pentamidine additionally by inhalation as compared with a historical cohort given azidothymidine alone. The results of the study suggest that a CD4-positive cell count of less than 50/microliters with a concomitant secondary lung infection promotes the development of pneumocystis carinii pneumonia. There was no correlation between the incidence of pneumocystis carinii pneumonia and the number of previous disease episodes. No systemic toxicity of pentamidine aerosol was established.

AIDS-Related Complex↗
PubMed1990

[Determination of thiocyanate in serum with ion-selective liquid membrane electrodes].

The manufacture of a liquid membrane type thiocyanate ion selective electrode on the basis of crystalviolet thiocyanate or methylene blue thiocyanate solved in nitrobenzene is described. This electrodes are available for the determination of the thiocyanate ion in agents with high levels on chlorid or protein, for instance in serum. Thiocyanate levels in serum from smokers and nonsmokers determinated by this electrodes differ significant from values that were obtained by the barbituric acid method, but they were in good agreement with values determinated by ion exchange chromatography. It can be assumed that its possible to ascertain the part of the dissociated thiocyanate by means of the ion selective electrodes and the ion exchange chromatography.

Chemical Phenomena↗
PubMed1989

Lectin binding and enzymatic deglycosylation of the cGMP-gated channel from bovine rod photoreceptors.

In order to investigate the lectin-binding properties of the photoreceptor cGMP-gated channel, solubilized and purified channel protein was incubated with immobilized lectins followed by reconstitution of unbound proteins. Of the lectins tested, only concanavalin A (ConA) was able to specifically sediment channel activity. A 240-kDa protein, which copurifies with the 63-kDa channel protein but does not bind ConA, was also found to be sedimented by the ConA-affinity matrix, thereby implicating that it is associated with the channel complex. Treatment of the purified channel protein with the enzyme glycopeptidase F in the presence of the denaturing detergent sodium dodecyl sulfate resulted in a rapid reduction of the apparent molecular mass by 1.90 kDa, and the abolition of ConA-binding. No intermediate molecular weight species were observed, suggesting that the channel protein is N-glycosylated at one site only. Under nondenaturing conditions, the kinetics of deglycosylation were distinctly two-phased: 50-60% deglycosylation was achieved rapidly; however, prolonged incubation was required to arrive at complete deglycosylation. Reconstitution experiments showed that deglycosylation had no significant effect on the kinetics of channel protein activation by cGMP.

Amidohydrolases↗
PubMed1989

Immunohistochemical assessment of splenic lymphocyte and macrophage subpopulations in patients with gastric cancer.

In order to assess the effects of malignant tumors on the immune system, 25 spleens from patients with gastric carcinoma were studied by in situ immunohistochemical methods for lymphocyte subsets and cells of the mononuclear phagocyte system. Highly significant reductions of CD4+ T cells (P less than 0.001), Ki M2+ and Ki M-3+ MPS cells (P less than 0.02 and P less than 0.05), and a stage-dependent reduction of Ki 67+ B cell proliferation activity (P less than 0.05) were seen in spleens of patients with gastric cancer. These results, which were obtained by morphologic methods in a noninvolved lymphatic organ, reflect the systemic immunosuppressive and immunodepleting effects of malignant tumors that are probably mediated by tumor-associated cytokines.

Adult↗
PubMed1989

Lysosomal (vacuolar) proteinases of yeast are essential catalysts for protein degradation, differentiation, and cell survival.

Mutants deficient in the vacuolar (lysosomal) endopeptidases proteinase yscA and proteinase yscB of the yeast Saccharomyces cerevisiae exhibit a drastically reduced protein degradation rate under nutritional stress conditions. The differentiation process of sporulation is considerably disturbed by the absence of the two endopeptidases. Also under vegetative growth conditions and under conditions of false protein synthesis, the two vacuolar endopeptidases exhibit some effect on protein degradation, which is, however, much less pronounced as found under starvation conditions. Proteinase yscA deficiency leads to rapid cell death when glucose-grown cells starve for nitrogen or other nutrients. Whereas overall protein degradation is affected in the endopeptidase mutants, degradation of two distinct false proteins analyzed is not altered in the absence of proteinase yscA and proteinase yscB. Also catabolite inactivation and degradation of fructose-1,6-bisphosphatase is not affected to a greater extent in the endopeptidase-deficient strains.

Cell Differentiation↗