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Biomedical subjects

J Wolfe

Publications and source records attributed to J Wolfe.

At least 199 records · Page 11Linked to original sources
PubMed1981

Virus infection of endothelial cells.

Endothelial injury is important in the pathogenesis of thrombosis, atherosclerosis, disseminated intravascular coagulation, and vasculitis. The ability of several common human viruses to infect cultures of endothelial cells obtained from human umbilical veins or bovine thoracic aorta was demonstrated. Indicators of infection included cytopathology, viral growth curves, and antigen detection by immunofluorescence. Herpes simplex virus type 1, adenovirus type 7, measles virus, and parainfluenza virus type 3 infected both human venous and bovine aorta endothelium. Mumps virus, poliovirus type 1, and echovirus type 9 grew only in human venous cells; coxsackievirus B4 infected only bovine arterial cultures; and cytomegalovirus, influenza A/Victoria/75 (H3N2) virus, and respiratory syncytial virus failed to grow in either cell culture. During replication some viruses caused acute lytic changes; some produced chronic, less destructive alterations; and other induced no apparent cytopathology. The results suggest that viral replication within endothelium may be important in the pathogenesis of viral disease of initiation of vessel-wall injury.

Adenoviruses, Human↗
PubMed1980

A possible skeletal substructure of the macronucleus of Tetrahymena.

Upon removal of chromatin from isolated macronuclei of tetrahymena, residual structures are obtained, the organization of which faithfully reflects the distinctive architecture of the macronucleus. Macronuclei are isolated by a new procedure in which cells are lysed by immersion in citric acid and Triton X-100. This method is rapid and efficient and leaves the nuclear structures stripped of nuclear envelope and nucleoli. The remaining interconnected chromatin bodies are structurally differentiated into a dense outer shell and a fibrillar inner core. The fibrillar component is identified as chromatin because it is removed upon digestion with DNase and extraction with 2 M NaCl. The dense shell of the chromatin body is unaffected by the digestion procedure, which leaves a skeletal structure comprised of hollow spherical bodies. Analysis of the protein composition by SDS acrylamide gel electrophoresis before and after digestion with DNase and RNase and high-salt extraction shows that histones are diminished, whereas the nonhistone protein composition remains unchanged. It was found the DNase not only extracts chromatin but also protects the nonchromatin structure from the otherwise disruptive effects of high-salt extraction. The method used for isolating the nuclei also affects the structure remaining after the digestion procedure the citric acid/Triton X-100 method enhances the stability of the interconnected spherical bodies. The results indicate that the method for isolating nuclei and the procedure by which chromatin is extracted are both major factors contributing to the detection of a possible nonchromatin nuclear skeleton.

Animals↗
PubMed1980

Long-term maintenance of Tetrahymena spp.

Simple media for Tetrahymena, using rat gut or soybean as the nutrient source are described. Cultures can be maintained in these media up to one year at room temperature.

Animals↗
PubMed1980

Clonal nature of the immune response to phosphocholine. IX. Heterogeneity among antibodies bearing M511 idiotypic determinants.

A fraction of serum anti-PC antibodies from mice immunized with PC-KLH expresses idiotypic determinants of the PC-binding myeloma MOPC-511. We examined the molecular heterogeneity of IgG antibodies bearing the M511 idiotype (Id) by analytical isoelectric focusing followed by in situ labeling with 125I-anti-M511. Antibodies with the M511 Id were shown to be conserved in many mouse strains and were distinct from T15 Id+ anti-PC antibodies. Two complex sets of M511 Id+ bands were observed and these were identified as M511 Id+ antibodies belonging to the IgG1 and IgG3 subclasses. Examination of responses in different individuals of a strain permitted identification of at least 4 to 6 IEF band groups. Thus, the M511 Id is a marker for a family of closely related molecules. Quantitative variations were observed in the expression of the M511 family within a strain and between strains of mice that occurred independently of expression of the dominant T15 Id+ fraction. These results support the concept of an M511 Id family and further suggest that there can be differential control mechanisms governing expression of individual clones or a family of closely related clones.

Animals↗
PubMed1979

Properties of bilayer membranes in the phase transition or phase separation region.

The increase in passive permeability of bilayer membranes near the phase transition temperature is usually explained as caused by either the increase in the amount of 'boundary lipid' present in the membrane, or by the increase in lateral compressibility of the membrane. Since both the amount of 'boundary lipid' and the lateral compressibility show a similar anomaly near the transition temperature, it is difficult to distinguish experimentally between the two proposed mechanisms. We have examined some details of both of the proposed pictures. The fluid-solid boundary energy, neglected in previous work, has been computed as a function of the domain size. For a single component uncharged lipid bilayer, the results rule out the existence of even loosely defined solid domains in a fluid phase, or vice versa. Thermodynamic fluctuations, which are responsible for anomalous behaviour near the phase transition temperature, are not intense enough to approximate the formation of a domain of the opposite phase. Turning next to lateral compressibility of bilayer membranes we have considered two-component mixtures in the phase separation region. We present the first calculation of lateral compressibility for such systems. The behaviour shows interesting anomalies, which should correlate with existing and future data on transport across membranes.

Lipid Bilayers↗
PubMed1979

Mass selection of conditional mating mutants of Tetrahymena thermophila.

The mating reaction in Tetrahymena thermophila includes a starvation period and two distinct cell interactions, co-stimulation and cell pairing, before the cells are cytoplasmically joined as conjugants. A selection procedure for harvesting mutants unable to mate at a restrictive temperature has been developed. A conjugant pair consisting of one cycloheximide-resistant cell and one wild-type cell (cycloheximide-sensitive) was itself sensitive to the drug. By adding cycloheximide and nutrient medium to a cross made at the restrictive and grow. Repetition of the selection procedure enriched for cells unable to conjugate at the restrictive temperature. The selected cells were able to grow at 38 degrees C and could conjugate at 28 degrees C. This procedure may be narrowed to select specifically for cell interaction mutants.

Animals↗
PubMed1978

Drosophila hemolymph proteins: purification, characterization, and genetic mapping of larval serum protein 2 in D. melanogaster.

Three of the major protein species present in the hemolymph of Drosophila melanogaster larvae just prior to pupation are absent from second instar larvae but accumulate rapidly during the third instar. This article describes the purification and characterization of one of these, larval serum protein (LSP) 2, using an immunological assay. It is a homohexamer of molecular weight about 450,000, with a polypeptide molecular weight of 78,000--83,000. Fast and slow electrophoretic variants of this protein map between the markers vin and gs, at 36--37 on chromosome 3.

Animals↗
PubMed1977

Biochemical and immunological studies on larval serum protein 1, the major haemolymph protein of Drosophila melanogaster third-instar larvae.

Larval serum protein 1 is the major haemolymph protein just before puparium formation in Drosophila melanogaster. It has been purified and characterised as a family of hexamers (molecular weight 450000-480000) of three immunologically related polypeptides (molecular weight 75000-81000). Homologous proteins, present in other dipterans, are similar in structure, amino acid composition and developmental profile.

Amino Acids↗