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Biomedical subjects

F Klein

Publications and source records attributed to F Klein.

At least 145 records · Page 8Linked to original sources

Immuno-epidemiology of malaria: a study in a tribal area of West Irian.

An investigation of malariometric indices in relation to immunoglobulin levels, rheumatoid factors, and antithyroglobulins was carried out on 78 members of the Arfak tribe near Manokwari in Western New Guinea, in the course of a WHO assessment of malaria control activities in that region. The population investigated had been exposed to a period of epidemic malaria, as indicated by the small differences in malariometric indices between consecutive age groups. Typically high spleen sizes were recorded, as found generally among Papuans in similar situations. Falciparum malaria was most prevalent, almost equal to cases of vivax and malariae malaria together. IgM levels were very high, while those of IgG, IgA and IgD were not elevated. Total serum protein was rather low. No correlation between malariometric indices, autoantibodies, and immunoglobulin levels could be found. In particular there was no correlation between IgM levels and spleen indices, such as has been found in many other surveys. It is suggested that splenomegaly may show no correlation with the IgM level in Papuan populations without previous selection.

Adolescent↗

Growth of pathogenic virus in a large-scale tissue culture system.

A model system is described for the mass propagation of Rift Valley fever (RVF) virus, utilizing large-volume fermentor units for suspension culture of tissue cells and the subsequent production of virus. Comparisons between laboratory- and fermentor-scale operations of tissue cell growth gave equivalent results. Cell viability dropped 24 to 30 hr postinfection with a subsequent virus yield between 10(8.0) and 10(9.0) mouse intracerebral median lethal doses per milliliter. Infecting volumes of tissue cell culture (20- or 40-liter working volumes) had no apparent effect on virus yields. Tissue cells grown under either oxidation-reduction potential- and pH-controlled or uncontrolled conditions showed little or no difference in their ability to produce RVF virus. We believe this tissue cell virus process to have potential application for large-scale production of vaccines for human or veterinary use or for the mass propagation of certain carcinogenic viruses for cancer research, once use of established lines for this purpose is accepted.

Animals↗

Ultrafiltration as a method for concentrating Rift Valley fever virus grown in tissue culture.

Filtration by means of a Diaflo ultrafilter was used to concentrate three 1,000-ml lots and one 3,000-ml lot of tissue culture-grown Rift Valley fever virus. Quantitation of both infectivity and total protein was achieved. Water treatment with continued ultrafiltration of the virus concentrate provided a final virus product approximately 99.25% free of low-molecular-weight materials originally present in the growth medium.

Animals↗

Growth of human lymphoid cells (Raji strain) in a five-liter fermentor.

Procedures used to produce an established line of mammalian cells (L cell) in a New Brunswick fermentor were adapted to propagate human lymphoid cells in suspended culture. Control of pH within defined limits was more effective for regulation of cell metabolism than control of oxidation-reduction potential. An unusually high rate of agitation was required.

Burkitt Lymphoma↗

Concentration of Rift Valley fever and Chikungunya viruses by precipitation.

Simple and efficient methods for concentrating Rift Valley fever (RVF) virus and chikungunya (CHIK) virus are described. Ammonium sulfate, potassium sulfate, or alcohol was used as a precipitating agent and the precipitate was resuspended to volumes suitable for further processing and purification. The methods permitted concentration of live RVF virus and CHIK virus about 100-fold with negligible losses of virus. RVF virus retained a high level of infectivity with potassium aluminum sulfate and alcohol, but CHIK virus retained a higher infectivity level with ammonium sulfate than with potassium aluminum sulfate. The data indicate that serum plays an important role in the concentration of both viruses, at least when the sulfate methods are used.

Animals↗