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Biomedical subjects

W Koch

Publications and source records attributed to W Koch.

At least 145 records · Page 8Linked to original sources
PubMed1984

Multiple gastric tumors--Crohn's disease.

A case of multiple, histologically in part differing gastric tumors and granulomatous inflammation in the upper gastrointestinal tract and terminal ileum in the same patient is presented. The differential diagnosis of granulomatous inflammation and a possible association between Crohn's disease and carcinoma is discussed.

Adenocarcinoma, Papillary↗
PubMed1984

Molecular analysis of the envelope gene and long terminal repeat of Friend mink cell focus-inducing virus: implications for the functions of these sequences.

We sequenced the envelope (env) gene and 3' long terminal repeat of a Friend mink cell focus-inducing virus (F-MCFV). We also sequenced the gp70 coding regions for two cDNA clones of another F-MCFV. The deduced amino acid sequence of the env gene products of both F-MCFVs were compared to the corresponding sequences of other MCFVs and of ecotropic viruses. The env polypeptides of the different viruses showed long stretches of homology in the carboxy-terminal half of gp70 and in p15env ("constant region"). The amino-terminal half of gp70 was very similar in all MCFVs, but showed extensive variations relative to the ecotropic viruses ("differential region"). This differential region in all MCFVs is of endogeneous origin. We show evidence that this region carries determinants for ecotropic or polytropic host range. No indication could be found that the env gene products determine the histological type of disease caused by particular MCFVs. When the long terminal repeats of F-MCFV and Friend murine leukemia virus were compared with those of other viruses causing either lymphatic leukemia or erythroleukemia, several nucleotides were localized which might determine the histological type of disease caused by these viruses.

Amino Acid Sequence↗
PubMed1983

Sequence analysis of Gardner-Arnstein feline leukaemia virus envelope gene reveals common structural properties of mammalian retroviral envelope genes.

We have sequenced the envelope (env) gene and most of the adjacent 3' long terminal repeat (LTR) of Gardner-Arnstein feline leukaemia virus subtype B. The LTR of this virus contains, at corresponding positions, all signal sequence elements known from other retroviral LTRs. The deduced amino acid sequence of the longest open reading frame was compared with env polypeptide sequences of several murine leukaemia viruses. This allowed us to predict the positions of both p12/15env and gp70 polypeptides as well as a hydrophobic leader polypeptide. The env polypeptides of the different viruses show long stretches of homology and similar hydrophilicity profiles in the p12env region and in the carboxy-terminal half of gp70 (constant region). The most extensive variations are confined to certain parts of the amino-terminal half of gp70 (differential region). In this region, however, feline leukaemia virus and murine mink cell focus forming viruses are still closely related. A correspondingly spaced pattern of identical, short amino acid sequences appears in three different parts of the env polyprotein, suggesting its evolution from a primordial env-related precursor by tandem duplications.

Amino Acid Sequence↗
PubMed1983

Nucleotide sequence of the envelope gene of Friend murine leukemia virus.

The envelope gene of the helper-independent, highly leukemogenic virus Friend murine leukemia virus was sequenced by using a molecular clone of a Friend murine leukemia provirus. The deduced amino acid sequences of the envelope proteins gp70 and p15env were homologous to the sequences of Moloney murine leukemia virus (86%) and Akv (76%). However, a stretch of about 40 amino acid residues near the middle of gp70 was dissimilar in Friend and Moloney murine leukemia viruses and Akv. In this type-specific region the gp70s of all three viruses contained more than 30% proline residues, giving this sequence a very rigid conformation. We suggest that this rigid and highly variable region of gp70 participates in infection by recognition of cell surface receptors and, in addition, might contribute to the different oncogenic spectra of murine leukemia viruses.

Amino Acid Sequence↗
PubMed1982

The significance of luminance on visual evoked potentials in diagnosis of MS.

In view of the fact that with psychophysical methods monocular luminance changes may increase the detection rate of pathological interocular-latency differences in MS patients, we studied the influence of stimulus luminance on the detection rate of MS using checkerboard visual evoked potentials. Decrements of stimulus luminance covering a range of three log units were unable to increase the detection rate of VEP. Regression coefficients of the luminance-latency functions did not differ in MS patients and normals. Contrary to the hypothesis tested, the diagnostic significance of VEP decreases with decreasing stimulus intensity.

Adult↗
PubMed1982

Comparison of impedance cardiography and echocardiography for measurement of stroke volume.

The relationship between stroke volume (SV) measured simultaneously by impedance cardiography (SVI) and echocardiography (SVE) has been analyzed. Change in stroke volume in 6 healthy volunteers was induced by passive head-up tilting (80 degrees) and by oral administration of the sympathomimetic drug amezinium. A correlation of r = 0.83 (p much less than 0.01) was found between SVI and SVE calculated by the equation: SVE = 16.0 + (0.528 x SVI). Though stroke volume is overestimated by impedance cardiography, the method may be useful for the clinical pharmacologist interested in a simple non-invasive tool to estimate stroke volume and change in it.

Cardiac Output↗
PubMed1982

[Exocrine pancreas function - does it change with age? (author's transl)].

We compared the excretory pancreatic function of a healthy young population (n = 18, mean age 31.8 years) with that of a healthy older people (n = 18, mean age 58.7 years) using a modified secretin-pancreozymin test which comprised short infusion of secretin, injection of pancreozymin, and repetition of this procedure immediately after the end of the collection period following the first stimulation. Secretion rate and bicarbonate following secretin, lipase, amylase and secretin rate following pancreozymin were significantly lower in the old than in the young after first and second stimulation. Trypsin was lower in the old than in the young following repeat stimulation. Trypsin was the only substance which was produced in smaller quantities after the second stimulation than after the first, i.e. pancreatic fatigue was demonstrable in the older age group.

Aging↗
PubMed1982

Structural and functional analysis of an rRNA operon and its flanking tRNA genes from Zea mays chloroplasts.

The complete analysis of an rRNA operon from Zea mays chloroplasts and its comparison with other plastidic or bacterial rRNA operons is presented. The maize operon contains structural genes for 16S, 23S and 4.5S rRNA species, a leader region proximal to the 16S rRNA gene and a 2.4 kb spacer between the 16S and 23S rRNA genes. Within the spacer DNA sequence are two tRNA genes which code for a tRNAIle and tRNAAla species but each gene is split by large intervening sequences of 949 and 806 bp, respectively. 4.5S rRNA is a structural equivalent of the 3' terminal region of bacterial 23S rRNA. The operon is flanked at its 5' side by a tRNAVal gene and at its 3' side by a 5S rRNA gene. Both these genes are probably not included in the large, primary precursor rRNA transcript.

Base Sequence↗
PubMed1981

[Echography of the upper abdominal vessels (author's transl)].

The newer generation of real-time ultrasonic equipment with its high resolution capacity permits not only visualization of the large abdominal vessels like the aorta and inferior vena cava, but in addition the tracing smaller visceral branches. The celiac trunk with its branches, the common hepatic artery and the splenic artery, the superior mesenteric and the two renal arteries can be visualized in 60-80% of all echographically examined patients. Consequently the new possibilities of abdominal echography with regard to assessment of the variations of vessels from the norm and intravascular processes such as thromboses are opened up. Changes in the courses of vessels permit conclusions on the seat and direction of growth of tumors.

Abdomen↗
PubMed1981

[Can cerulein replace pancreozymin in the diagnosis of exocrine pancreatic function? (author's transl)].

The effect of the decapeptide cerulein on exocrine pancreatic function was compared with pancreozymin by means of intraindividual double stimulation. 100 ng/kg bw/45 min of synthetic cerulein led to a greater enzyme excretion than 2 U/kg bw pancreozymin. This increase in enzyme secretion was independent of whether the pancreas function was normal or disordered. In the selected experimental procedure, cerulein increased the excretion of enzymes (chymotrypsin, trypsin, lipase, amylase) whether it was infused in connection with or before an injection of pancreozymin. Cerulein can therefore completely replace pancreozymin in the diagnosis of pancreatic function.

Ceruletide↗
PubMed1981

On the mechanism of inhibitory effect of violamycin antibiotics on the transcription by bacteriophage T3-induced RNA polymerase.

The effect of three components of the anthracycline antibiotic violamycin on the transcription of bacteriophage T3 DNA by bacteriophage T3-induced RNA polymerase has been investigated in a cell-free system. The glycosides of violamycin BI possess the highest inhibitory activity, whereas those of violamycin BII and violamycin A show a reduced inhibitory effect. Concentrations of violamycin BI depressing the incorporation of (3H)UMP into RNA chains have only a slight effect on the binding of the T3 RNA polymerase to T3 DNA and on the incorporation of GTP as the first nucleotide. This shows that the primary target of the antibiotic is not the initiation of the RNA synthesis. The binding of violamycin BI to T3 DNA causes a strong reduction of the elongation rate of the RNA chains.

Aminoglycosides↗