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Biomedical subjects

H K Müller

Publications and source records attributed to H K Müller.

At least 37 records · Page 2Linked to original sources
PubMed1984

Basal lamina redevelopment in tumours metastatic to brain:an immunoperoxidase study using an antibody to type-IV collagen.

The basal lamina in a variety of metastatic tumours in brain was assessed with an antibody to type-IV collagen and the indirect immunoperoxidase technique. The antibody was raised in rabbits against type-IV collagen isolated from human placental tissue. Basal lamina redevelopment was demonstrated around individual melanoma cells, between melanoma cells and cerebral parenchyma, and at the tumour-stroma interface in both metastatic melanoma and metastatic carcinoma. At the periphery of metastatic carcinomatous deposits, no basal lamina was observed between tumour cells and the adjacent cerebral parenchyma. Basal lamina staining other than that of cerebral vessels was absent in deposits of poorly differentiated tumours which were unaccompanied by the development of a tumour stroma. It is concluded that metastatic tumours retain the ability to produce basal lamina and, in the case of metastatic epithelial tumours, the redevelopment of basal lamina is dependent on interaction with mesenchymal tissue. The stromal dependency of basal lamina formation by metastatic epithelial tumours suggests the reactivation of a control mechanism acting in normal tissue. Although basal lamina formation in metastatic melanoma can occur in the absence of mesenchymal tissue, there may be some interaction between tumour cells and stroma in the redevelopment of basal lamina at the tumour-stroma interface.

Biopsy↗
PubMed1984

Bufuralol metabolism in human liver: a sensitive probe for the debrisoquine-type polymorphism of drug oxidation.

The genetically controlled polymorphism causing decreased metabolism of debrisoquine is closely related to that of the metabolism of bufuralol and numerous other drugs and has important clinical consequences. A sensitive in vitro assay was developed which quantifies the production of 1'-hydroxy-bufuralol (carbinol) from bufuralol in human liver microsomes. Initial formation rates of carbinol suggested Michaelis-Menten kinetics with an apparent KM of 61 and 171 mumol l-1 and Vmax of 3.2 and 5.8 nmol mg-1 microsomal protein h-1 in two human liver samples. The Vmax in microsomes of thirty-two liver samples was 4.2 +/- 1.0 (SD) nmol carbinol mg-1 protein h-1. Metabolism of debrisoquine in vivo, as expressed by the 'metabolic ratio' of debrisoquine over 4-OH debrisoquine correlated (r = -0.65, P less than 0.01; n = 18) with carbinol production rate in microsomes in vitro. Microsomes of one individual identified as poor metabolizer of debrisoquine in vivo showed reduction of carbinol formation to 1.97 nmol mg-1 h-1. Mixing his microsomes with those of an extensive metabolizer resulted in additive formation of carbinol excluding mediation of the defect by a soluble inhibitor. These data support the concept of a primary defect in microsomal oxidation of bufuralol. The described assay offers a sensitive tool to investigate the molecular mechanism of the 'debrisoquine polymorphism'.

Adrenergic beta-Antagonists↗
PubMed1980

[Development of medical sciences in China].

Three periods or stages can be recognized in the development of medicine in China. The first one, being the indigenous medical practice, has its own philosophical approach and can therefore not simply be combined with Western medicine. The second period, in which medical missionaries introduced modern medicine was still a time of laissez-faire and pestilence. The third stage was ushered in by the liberation in 1949 and is characterized by the fact that the government no longer regards health as the private affair of the individual but as a task for the whole community. A number of endemic and epidemic diseases were conquered mainly through close cooperation between the population and medical workers. Success must be regarded as in an important part due to land reform and the eradication of famine. Further improvement in health care will depend to a great deal on improvement in living standards and a lessening of population pressure. As family planning meets resistance for economic and other reasons, only specific measures by the state can bring about a change in attitude. The progress in preventive measures is matched by advances in the technical aspects of medicine and especially too in medical education.

China↗
PubMed1978

DNA sequence homology estimation by combinatorial analysis of endonuclease restriction data.

A combinatorial analysis of the products of DNA cleavage by restriction endonucleases permits an estimation of the sequence homology between closely related linear DNAs. The main assumption to be made is that fragments of identical length represent equivalent sections of the genomes. All patterns of common and varying restriction sites compatible with the results of the electrophoretic analysis of fragment sizes can be enumerated, each yielding an estimate of the proportion of sequences of restriction site length common to both DNAs. From this, sequence homology is derived by using a model of randomly distributed point mutations relating the two genomes. Possible limitations of the approach are discussed.

Base Sequence↗
PubMed1978

Inverted terminal repeats in rabbit poxvirus and vaccinia virus DNA.

In both rabbit poxvirus and vaccinia virus DNA have demonstrated an identical distribution of eight HinfI. The length of the terminal repeats was found to be 3.4 to 3.6 megadaltons (Mdaltons) for rabbit poxvirus DNA and 7.4 to 8.0 Mdaltons for vaccinia virus DNA. Maps of the HinfI restriction sites within isolated EcoRI end fragments of rabbit poxvirus and vaccinia virus DNA PHAVE DEMONSTRATED AN IDENTICAL DISTRIBUTION OF EIGHT HinfI sites in an internal part (approximately 2 Mdaltons) of the EcoRI end fragments of the two genomes.

Animals↗
PubMed1978

[The smallpox vaccination strain MVA: marker, genetic structure, experience gained with the parenteral vaccination and behavior in organisms with a debilitated defence mechanism (author's transl)].

The MVA virus is a lab virus ideally suited for vaccination of both man and animal which can be differentiated from the known Vaccinia strains by the use of numerous biological markers. Its reduced virulence for the chick embryo, for experimental animals and for man is a particularly characteristic feature. With the exception of chick embryo fibroblasts, the MVA virus grows in cell cultures only abortively. This applies particularly to cells of human origin in which the cytopathic effect and plaque formation are completely missing. The restriction analysis of the DNS of the MVA virus demonstrates that its genetic structure differs from that of the CVA basic virus and other orthopox viruses. In contrast to the WHO reference strain Elstree, the MVA virus has a genome shortened by about 9 per cent. The use of the MVA virus for human vaccination is particularly indicated in persons to be vaccinated for the first time and likely to entail a risk (on account of allergies etc.) because it brings about a state of revaccination without complications. The MVA virus can be administered in intracutaneous, subcutaneous or intramuscular injections. Innocuoursness and successful vaccination have been demonstrated in more than 120000 persons. While other Vaccinia strains, such as the Elstree virus, experience a drastic increase of virulence in the immunosuppressed organism (subjected to whole-body irradiation), the MVA virus cannot be activated not even in this situation.

Animals↗
PubMed1977

HindIII and Sst I restriction sites mapped on rabbit poxvirus and vaccinia virus DNA.

The DNAs of two closely related orthopoxviruses, rabbit poxvirus (RPV) and vaccinia virus (VV), were mapped by overlapping-fragment analysis using restriction endonucleases HindIII and Sst I. The exact arrangement of these fragments was accomplished by total digestion of isolated partial restriction products and by end-fragment determination. RPV and VV DNAs showed identical restriction patterns in an internal region comprising approximately 60% of the genome. The size, by electrophoretical analysis of the RPV DNA, was 118 X 10(6) daltons, some 6 X 10(6) daltons less than VV DNA. The two opposite terminal restriction fragments of RPV DNA cross-hybridized to each other.

Base Sequence↗