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Biomedical subjects

G Schmidt

Publications and source records attributed to G Schmidt.

At least 595 records · Page 33Linked to original sources
PubMed1977

[Changes of erythrocyte criteria of the guinea pig under hypoxia].

In the present study the adequacy of erythrocytic criteria for the diagnosis of hypoxia has been investigated in animal experiments. Guinea pigs were exposed to a defined hypoxia (pO2 equals 48 mm Hg approximately equal to 9000 m height) for 24 and 72 hrs. With increasing duration of hypoxia there is observable a distinct rise in reticulocyte count, 59Fe incorporation and the proportion of erythroblasts in the bone marrow. Hematocrit and hemoglobin concentration have increased significantly after hypoxia compared with the control animals. The mean cellular hemoglobin content shows a marked fall with the duration of hypoxia. The density distribution curves show under hypoxia a shift to lower densities and, therefore, appear to be well suited for the diagnosis of hypoxic states. The activities of the erythrocytic enzymes, G-6-PD and GOT, are increased after 24 and 72 hrs of hypoxia. The GOT isoenzyme pattern is shifted with continued hypoxia in favour of the mitochondrial GOT. The changes of enzyme activities are not pronounced enough under hypoxic conditions to be used for diagnositc purposes.

Animals↗
PubMed1976

The cell-wall lipopolysaccharide of Escherichia coli K-12. Structure and acceptor site for O-antigen and other substituents.

The lipopolysaccharides of two wild-type Escherichia coli K-12 strains, two core-deficient mutants and one SR recombinant with Salmonella typhimurium specificity were analyzed. The respective oligosaccharides were dephosphorylated and methylated. Chemical analysis of the oligosaccharides and mass spectrometric analysis of their methylated derivatives indicated the presence of core structures with different degrees of completion. In different strains of E. coli K-12 the complete core is substituted at the non-reducing end with N-acetylglucosamine or with another substituent. There are indications that the latter may be N-acetylmannosaminuronic acid. In the SR recombinant the complete (N-acetylglucosamine-free) K-12 core is substituted with one S-specific oligosaccharide of S. typhimurium. The attachment site for all these substituents is the 6-position of the non-reducing core-terminal glucose. The heterogeneity of the K-12 core preparations and mode and nature of their substitution are discussed.

Antigens, Bacterial↗
PubMed1976

Immunochemical studies on lipopolysaccharides from wild-type and mutants of Escherichia coli K-12.

Lipopolysaccharides from a number of mutants of Escherichia coli K-12 were investigated by means of chemical and serological methods. Inhibition of passive hemagglutination and inhibition of precipitation show that L-rhamnose is the immunodominant sugar in the lipopolysaccharide from wild-type E. coli K-12. The disaccharide rhamnosyl-KDO (where KDO is 3-deoxy-D-manno-octulosonic acid) was isolated and characterized after mild acid hydrolysis of the lipopolysaccharide. It is concluded that rhamnose is present in the innermost part of the core as a side-chain substituent on KDO. From crosses between an E. coli K-12 donor and E. coli O8, hybrids were obtained which contained either one or both of the donor rfa and rfb clusters. Serum absorption studies with lipopolysaccharides from these hybrids indicated that the histidine-linked rfb cluster is responsible for the presence of rhamnose in the K-12 core oligosaccharide. Using paper chromatography of 32P-labelled lipopolysaccharides we have found heterogeneous lipopolysaccharide in two strains as well as some differences between two wild-type strains. The latter difference is believed to be due to varying contents of KDO-linked ethanolamine phosphate. The overall results presented together with those described in the companion paper clearly show that the core oligosaccharide in E. coli K-12 has a structure different from the types previously described for other strains of E. coli (designed coli R1 to coli R4).

Alleles↗
PubMed1976

The simultaneous determination of lidocaine and procainamide in serum by use of high pressure liquid chromatography.

This report describes an accurate, sensitive rapid procedure for the determination of lidocaine and procainamide at therapeutic concentrations in serum. The drugs and an added internal standard (procaine) are extracted from serum using charcoal adsorption. The analysis is carried out by high pressure liquid chromatography on a reverse-phase column using buffered aqueous acetonitrile as the mobile phase. Chromatography is complete in 10 min. C.V. values of 10% and 6% for concentrations of 1 mg/l and 20 mg/l, respectively, are attainable routinely. Total analysis time is 15 min.

Chromatography, High Pressure Liquid↗
PubMed1976

[Non-resecting surgery for gastroduodenal ulcer. I. Pathophysiological principles (author's transl)].

Selective proximal vagotomy with pyloroplasty is a method which permits ulcers to be operated on with less morphological and pathophysiological disturbances than is possible with any other method. After ingestion, a reactive yet reduced acid secretion is still possible through the gastrin stimulus. The retained vagal antral release of gastrin seems to be without importance to the denervated delomorphous cells. Side effects of this type of vagotomy are small. The disturbances of motility and evacuation which also occur here can easily be corrected by an additional pyloroplasty suitable in shape and function.

Animals↗
PubMed1976

[Frequency of chronic non-suppurative destructive cholangitis and primary biliary cirrhosis in comparison with other chronic inflammatory liver diseases].

Primary biliary liver disease was diagnosed and verified by histology and demonstration of antibodies against mitochondrial proteins in 73 patients between 1970 and 1974. Comparing cases between 1950 and 1961 and between 1970 and 1974 with the frequency of other chronic inflammatory liver diseases it was found that figures for advanced primary biliary cirrhosis remained unchanged during both periods whereas early stages of primary biliary disease were detected far more frequently in the latter period. One case with chronic non-suppurative destructive cholangitis or complete primary biliary cirrhosis was outnumbered by 8 cases of chronic aggressive hepatitis and 15 of liver cirrhosis of various aetiologies in Kassel. The relations in Göttingen were 1 : 5 and 1 : 6, respectively. Primary biliary diseases are no longer rare.

Aged↗
PubMed1976

[Late diagnosis of malignant renal tumors. Review and case reports (author's transl)].

In this paper the problem of early diagnosis in hypernephroid carcinoma of the kidney is explained. Hematuria remains inspite of other possible causes suspect for tumor as long as a tumor is certainly excluded. The different methods for diagnostic and characteristic signs for tumor in the X-ray (EVP) are discussed. Three cases of late diagnosis of hypernephroid carcinoma of the kidney, due to long time not explained symptoms, are described.

Adenocarcinoma↗
PubMed1976

The effects of perceived status and linguistic diversity upon judgment of speaker attributes and message effectiveness.

It has been shown previosly that high linguistic diversity positively affects listeners' judgments of speaker attributes and message effectiveness. Diversity refers to the degree of lexical and syntactic redundancy in a message. In the present study it was predicted that listeners' initial perceptions of a speaker's status would influence their judgments of high- and low-diversity messages. Ss were 46 male and female undergraduates at The University of Iowa. Three competing predictions were offered, and the results supported a status-attribution explanation. A high-status speaker was rated especially negatively when he delivered a low-diversity message. High- and low-diversity messages did not differ in their evaluative consequences for a low-status speaker; in this case both message types produced ratings that fell between the relatively positive or negative ratings given to the high-status speaker.

Communication↗
PubMed1976

Genetic transfer of Salmonella O antigens to Escherichia coli O8.

His+ hybrids from a cross between a Salmonella typhimurium donor and an Escherichia coli O8 recipient expressed E. coli O8 specificity and in addition Salmonella O4,12-specificity. This indicated that the recipients had received the his-linked donor rfb cluster determining the synthesis of S. typhimurium O-specific repeat units and that the rfb genes of both mating partners are functional in these hybrids. Chemical analyses showed that the hybrids contained an E. coli O8 lipopolysaccharide (O antigen) and a S. typhimurium specific lipopolysaccharide with only one O-specific repeat unit (SR antigen). O8-negative mutants selected from the O8-positive hybrids retained the Salmonella O-specificity and represent semi-rough (SR) forms, because the rfc gene(s) determining the polymerization of repeat units has not been transferred. Attempts to introduce the S. typhimurium rfc locus into E. coli O8 remained unsuccessful. Crosses between a S. typhi donor and E. coli O8 gave rise to smooth (S) and SR His+ recombinants exhibiting only S. typhi O-specificity. The smooth recombinants are assumed to have obtained the his-linked rfb cluster and in addition the rfc gene(s) of the donor. The exchange of the rfb region of such smooth recombinants by that of a S. typhimurium donor led to smooth hybrids with O4,(5), 12-specificity. The phenotypically smooth recombinants exhibited concomitantly S- and SR-lipopolysaccharides of S. typhi and S. typhimurium O-specificity, respectively.

Antigens, Bacterial↗
PubMed1976

Role of a lipopolysaccharide gene for immunogenicity of the enterobacterial common antigen.

It is known that only certain strains of the family of Enterobacteriaceae, notably rough (R) mutants with the type R1 or R4 core, evoked antibodies in high titers against the common enterobacterial antigen (CA) after immunization of rabbits with heated cell suspensions. The present investigation deals with genetic and immunochemical aspects of certain R1 and R4 mutants isolated from Escherichia coli 08 and various Shigella serotypes which, unexpectedly, do not induce CA antibody formation. Immunochemical and genetical (transduction and conjugation) experiments revealed that the rough phenotype of these special mutants was evoked by a mutation of pyrE-linked rfa gene, called rfaL, which is involved in translocation of O-specific polysaccharides onto the lipopolysaccharide core. The transduction of the defective rfaL, allele into appropriate rough recipients results in transductants which have simultaneously lost the ability to evoke CA antibodies. This finding suggests that a close connection exists between the function of the rfaL gene and the expression of CA immunogenicity in R1 and R4 mutants. One of the strains synthesized neither O-hapten nor CA, suggesting a mutation in a region equivalent to the rfe genes of Salmonella.

Animals↗