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Biomedical subjects

G Walter

Publications and source records attributed to G Walter.

At least 163 records · Page 9Linked to original sources
PubMed1989

The stereotype of the mad psychiatrist.

The stereotype of the mad psychiatrist is examined. There is initial consideration of the "popular" model of madness. It is suggested that there is no firm evidence that psychiatrists suffer more frequently from "popular madness" than other medical practitioners. The paper subsequently explores the stereotype's functions, origins, means of propagation and range of effects. It emerges that members of "the first generation" of psychiatrists were labelled as mad. It is inferred that the stereotype may not be about to change. The paper invokes the conceptually closely-related literatures and attendant terminologies of stereotyping, mythology, labelling, deviance, prejudice and stigma.

Career Choice↗
PubMed1989

[Phoresy and hyperparasitism in Ornithomya (Diptera, Hippoboscidae) in the Federal Republic of Germany].

243 louse-flies of the genus Ornithomya were examined for mites and Mallophaga. 12 out of 71 O. fringillina and 4 out of 153 O. avicularia were infested by Microlichus avus. Myialges uncus were found on 5 O. avicularia. One O. avicularia was infested by Myialges pari. Mallophaga were found on 8 O. avicularia. The following species were identified: Allobruelia abluda, A. amsel, Turdinirmus merulensis, Trichodectes sp., Brueelia sp.

Animals↗
PubMed1989

[The infection process with Sphaerospora renicola (Myxosporidia)].

New data are presented on the development of infection by S. renicola in common carp within the first 15 weeks of their life. The infection of parasite-free common carp succeeded by myxospores as well as by feeding carp kidneys with and without spores in laboratory experiments. In field experiments one year-old parasite-free common carp were successfully infected.

Air Sacs↗
PubMed1988

Sensitive two-site sandwich enzyme immunoassay with antipeptide antibodies for detection of viral antigens.

Two-site sandwich ELISAs with antipeptide antibodies were developed for measuring the amounts of polyoma virus medium T and SV40 virus large T antigen in extracts from virus infected and transformed cells. In order to exclude crossreactive proteins, two antipeptide antibodies directed against different regions of the antigen were used in series. Both antigenic determinants have to be recognized for the assay to score positive. A positive signal was obtained with as little as 10 microliter of polyoma virus infected cell lysate and 100 microliter of extract prepared from medium T antigen-transformed FR18-1 cells which were shown to contain 37 and 15 pg of medium T antigen, respectively. This two-site sandwich ELISA is a sensitive tool to detect novel or closely related proteins.

Animals↗
PubMed1988

In vitro phosphorylation of SV40 large T antigen.

Phosphorylation of simian virus 40 large T antigen (large T) was investigated in vitro. "Autophosphorylation" of large T resulted in the modification of Ser106, Ser112, Ser123, Thr124, either Ser676, Ser677, or Ser679, and Thr701. All of these residues were also found to be phosphorylated in vivo. Reaction of large T with purified casein kinase I resulted in phosphorylation of Ser123, possibly Thr124, and either Ser676, Ser677, or Ser679, while purified casein kinase II phosphorylated Ser106 and possibly Ser112. Submolar amounts of phosphate were transferred to large T indicating that only a fraction of large T served as substrate for the casein kinases. Removal of serine-bound phosphate did not affect the subsequent autophosphorylation or phosphorylation by casein kinase I and II. No phosphorylation at in vivo sites was observed with the cAMP-, cGMP-, or Ca2+/phospholipid-dependent protein kinases, or with the protease-activated kinase I and II.

Antigens, Polyomavirus Transforming↗
PubMed1988

Developmental expression of two forms of pp60c-src in mouse brain.

The expression during mouse development of two forms of protein-tyrosine kinase pp60c-src, pp60 and pp60+, was investigated. At embryonic day 9 (E9), only pp60 was detected in whole-brain lysates. A trace of pp60+ was first seen at E10. In E18 embryos and in adults, pp60+ was the predominant form of pp60c-src in forebrain and midbrain lysates.

Animals↗
PubMed1988

Progressive loss of neuronal src protein in postnatal weaver and staggerer cerebellum.

Two forms of the c-src protein-tyrosine kinase, pp60c-src, are detectable in the central nervous system. One form pp60+, appears to be exclusively expressed in neurons and is characterized by insertion of 6 amino acids compared to its non-neuronal counterpart, pp60. These 2 proteins were studied in the mutant mouse strains weaver and staggerer with postnatal loss of cerebellar granular neurons. We found a continuous postnatal decline of the neuronal form of pp60c-src, pp60+, in the cerebellum of both mutants concomitant with the degeneration of cerebellar granule cells. This indicates that granular neurons provide the main source for pp60+ in the cerebellar cortex.

Animals↗
PubMed1988

Specific kinase activity and phosphorylation state of pp60c-src from neuroblastomas and fibroblasts.

Several tumor lines of neuronal origin were assayed for the presence of two forms of pp60c-src, designated pp60 and pp60+. To determine the specific kinase activity of pp60 and pp60+, an enzymatic analysis was carried out with neuroblastoma LA-N-5, containing a high level of pp60+, neuroblastoma SK-N-SH, containing a low level of pp60+, fibroblast FSD, containing pp60 but no pp60+, and Rous sarcoma virus transformed 3T3 cells, SR-3T3, containing pp60v-src. Km values for Mg2+-ATP of approximately 21, 8, 17 and 13 microM were determined for pp60src kinase from LA-N-5, SK-N-SH, FSD and SR-3T3 respectively, using enolase as a substrate. The Vmax values for pp60c-src kinase from LA-N-5, SK-N-SH and FSD were similar. The Vmax value of pp60v-src was about 50-fold higher. Thirteen distinct phosphopeptides were found in tryptic digests from pp60 and pp60+ labeled in vivo with [32P]. The presence of one phosphopeptide, derived from the N-terminus, correlated with the level of pp60+ in neuroblastoma cells, but a small amount of this peptide was also detected in fibroblasts. Only phosphoserine was detected in the N-terminus of pp60 and pp60+. Our data strongly suggest that the six extra amino acids, present in pp60+ but not in pp60, do not significantly alter the specific kinase activity of pp60+, but might influence its phosphorylation state.

Animals↗
PubMed1988

Effects of high doses of diethylcarbamazine on adult Onchocerca volvulus examined by the collagenase technique and by histology.

Thirty adult male nodule carriers from a hyperendemic onchocerciasis area in the Liberian rain forest were treated with high doses of diethylcarbamazine (30 mg/kg/d) over one week. Another ten patients received placebo tablets and served as a control. All detectable nodules were removed from half of the patients at two months and from the remaining patients at ten months after chemotherapy. The adult worms in the nodules were examined for pathological alterations by the collagenase technique including embryogram, and by histology. No macrofilaricidal effect was observed at either time, and no significant reduction of microfilariae in the uteri of the female worms or in the tissue of the nodules was seen. Two months after the therapy there was a significant increase of degenerated stretched intrauterine microfilariae but this effect was no longer observed after ten months. No pathological effect was seen on the intrauterine coiled microfilariae. On the contrary, their number had significantly increased after ten months which could mean a stimulation of the embryogenesis. No effect on spermatogenesis was observed. Both techniques, the collagenase digestion and the histological examination of the nodules, provided similar results to demonstrate that there was no marked long lasting effect on O. volvulus after a treatment with high doses of diethylcarbamazine.

Animals↗
PubMed1988

Anti-idiotypic antibodies: powerful tools in diagnosis and therapy.

Mouse x mouse hybridomas secreting monoclonal anti-idiotypic antibodies have been prepared from BALB/c mice immunized with syngeneic monoclonal antibodies specific for IgE, AFP, CEA and TSH respectively. The hybridomas were selected on the basis that the secreted antibodies competed with antigen for binding to the immunizing idiotope. Using IgE and AFP as a model it could be shown that syngeneic antigen inhibitable monoclonal anti-idiotypic antibodies can act well as antigen surrogate. Thus a complementary idiotype-anti-idiotype antibody pair could be used in a competitive assay wherein the extend of idiotype-anti-idiotype complex formation is inversely proportional to the amount of antigen in the sample. Apart from this a lot of human and animal studies have shown that this interaction between idiotype and anti-idiotype could be utilized to prevent certain infectious diseases and to treat some kinds of cancers.

Animals↗
PubMed1988

Histological examination of onchocercomata after therapy with ivermectin.

During chemotherapy trials in hyperendemic onchocerciasis areas in West Africa 15 adult nodule carriers in Liberia and 24 patients in Mali received single doses of ivermectin (150 or 200 micrograms/kg). Nodules were extirpated two, six and ten months after therapy and examined histologically. No macrofilaricidal effect of ivermectin was observed. Two months after therapy, in 93% of all female worms with intrauterine stretched microfilariae nearly all microfilariae were degenerated. The percentage was lower after ten months but still significantly higher than in untreated control groups. Ivermectin did not cause degeneration of the intrauterine coiled microfilariae. But the percentage of the female worms with coiled microfilariae was significantly lower two and ten months after therapy than that in the placebo or untreated control groups. Correspondingly, the percentage of nodules with intact microfilariae in the nodule tissue was also significantly lower throughout the examination period than that of the untreated control groups. There was not observed any effect on the spermatogenesis and spermatozoa were found frequently in the uteri of female worms. Using the method of histology, the long lasting inhibitory effect of a single dose of ivermectin on the intrauterine production of microfilariae could clearly be demonstrated. This proves the value of histology for the assessment of drug effects on adult O. volvulus.

Animals↗
PubMed1988

[The seasonal dynamics of Sphaerospora renicola (Myxosporidia) in carp (Osteichthyes)].

We observed 2 different types of the course of incidence of sporogonic phase and blood phase. Type I shows in both phases a maximum in the first summer, a minimum in winter or autumn and a second maximum between late autumn and second summer. In this case the sporulation was especially distinct with the first maximum. Type II starts in the first summer with the blood phase without occurrence of the sporogonic phase (and the swim-bladder phase), which appears only from autumn until the second summer in a form of three peaks. Here the sporulation was successful only in the third peak. Hitherto there has been no other example of that type. The course of incidence, characterized by peaks and valleys, is regarded as an expression of an internal rhythm of different phases of the parasite and not as caused by the declining of infection and by reinfection. Premunition (if a hitherto unknown reservoir phase is surviving) or age resistance and/or less chance of coincidence of infective stages and older carps are supposed to be the cause of the rare occurrence of the 3 known phases in carps more than 14-15 months old. There are some indications of the infection of carps by carps. Carassius au. auratus was ascertained as a new host for S. renicola in a field experiment.

Air Sacs↗
PubMed1988

[Coincidental appearance of PKD and Sphaerospora sp. (Myxosporidia) in stock of Salmo gairdneri (Osteichthyes)].

For the first time in Europe simultaneous occurrence of PKX and Sphaerospora sp. is recorded in Salmo gairdneri. Myxosporidian (?) forms hitherto not described have been observed in the kidney interstitium and the epithelium of the renal tubules, sporadically also in the swimbladder wall and the intestinal wall, besides the typical PKX organism in the kidney interstitium. Sporogonic stages and spores of a Sphaerospora species have been found in the lumen of the renal tubules. Neither the exact identification of the Sphaerospora species has been possible, nor the final proof, whether the luminal form, the hitherto undescribed extraluminal forms and PKX belong to one another.

Air Sacs↗
PubMed1988

On the nature of IgG dimers. II. Idiotype--anti-idiotype complexes of polyclonal and monoclonal origin: size distribution patterns and molecular geometries.

Electron micrographs of a fraction containing dimers isolated from pooled human polyclonal immunoglobulin G (IgG) suggest essentially a cyclic geometry compatible with bivalently associated monomers. It is obvious that such a structure can be produced by idiotype (Id)--anti-idiotype (anti-Id) interactions where the latter are able to neutralize certain combining site related Id functions. Accordingly, antibody (ab) activities against tetanus toxoid (tt) and rubella antigen (ag) were found to be almost exclusively confined to the monomeric molecules in preparations composed of monomers and dimers only. Moreover, electron micrographs of complexes prepared from a murine monoclonal Id as well as anti-Id reveal the presence of ring complexes, especially of cyclic tetramers. Gel filtration patterns of mixtures containing equimolar concentrations (concns) of such abs (1.6 x 10(-6) M) show, correspondingly for 9 different Id--anti-Id pairs and therefore probably representing a more common feature, mainly the formation of even-numbered complexes, especially tetramers. That is basically in accordance to an equilibrium model developed by Archer and Krakauer but not from a quantitative point of view because non-ideality terms had not been originally included. Despite taking strain energies determined by Schumaker et al. for cyclic complexes of polyclonal rabbit abs and a bivalent hapten into account for computation of size distribution patterns, the predominant formation of dimers was, nevertheless, again predicted by the modified theory in contrast to the experimental results. Fundamental conformity could only be achieved by further decreasing one of the statistical factors, namely the ring closing factor, which theoretically influences the generation of cyclic dimers. Therefore, referring to the experimental results of Schumaker et al., we postulate a strain energy well above 700 cal/mol for cyclic dimers produced by interacting Ids and anti-Ids. In general, the findings confirm predictions based on the interpretation of recent kinetic studies.

Animals↗
PubMed1987

Lymphangiomyomatosis: a report of three cases treated with tamoxifen.

Three cases are reported of lymphangiomyomatosis with pulmonary and abdominal manifestations. Two had a chylous pleura effusion, while the third presented a retroperitoneal manifestation, which was completely resectable. Antiestrogen therapy with tamoxifen was administered in all three cases. Two patients died of pulmonary progression after 4 months of therapy. The third is still alive, with stable disease for more than 6 years, and has been receiving tamoxifen for 66 months. These observations indicate that antiestrogen treatment may be as effective as oophorectomy when started at an early stage of the disease.

Abdominal Neoplasms↗