Hemodynamic studies in acute venous stasis edema in rats

An increase in venous pressure in the rat tail is known to result in acute edema. Acute venous stasis edema of the rat tail was induced by applying a force-controlled banding of standard tension (200 g) proximally for a period of 6-12 h. The hemodynamic changes of acute venous stasis edema were evaluated using non-invasive plethysmography, fluorescence angiography, computer thermography and invasive radioactive microsphere techniques. It is shown here that reduction of tail circulation to 40% of the control value is followed by prolonged vascular disorder characterized by genesis of reversible edema, increased total blood flow to the tail and decreased local cutaneous blood flow, without affecting the general hemodynamics. The cutaneous circulation (decreased blood flow) seems to be principally involved in the edemogenic response, whereas the deeper vessels (hyperemia) may or may not play a determinant role in acute experimental venous stasis edema in rats.     

Human hepatitis B vaccine from recombinant yeast

The worldwide importance of human hepatitis B virus infection and the toll it takes in chronic liver disease, cirrhosis and hepatocarcinoma, make it imperative that a vaccine be developed for worldwide application. Human hepatitis B vaccines are presently prepared using hepatitis B surface antigen (HBsAg) that is purified from the plasma of human carriers of hepatitis B virus infection. The preparation of hepatitis B vaccine from a human source is restricted by the available supply of infected human plasma and by the need to apply stringent processes that purify the antigen and render it free of infectious hepatitis B virus and other possible living agents that might be present in the plasma. Joint efforts between our laboratories and those of Drs W. Rutter and B. Hall led to the preparation of vectors carrying the DNA sequence for HBsAg and antigen expression in the yeast Saccharomyces cerevisiae. Here we describe the development of hepatitis B vaccine of yeast cell origin. HBsAg of subtype adw was produced in recombinant yeast cell culture, and the purified antigen in alum formulation stimulated production of antibody in mice, grivet monkeys and chimpanzees. Vaccinated chimpanzees were totally protected when challenged intravenously with either homologous or heterologous subtype adr and ayw virus of human serum source. This is the first example of a vaccine produced from recombinant cells which is effective against a human viral infection.     

Molecular cloning of cDNA encoding a murine haematopoietic growth regulator, granulocyte-macrophage colony stimulating factor

DNA clones specifying the murine granulocyte-macrophage colony stimulating factor have been isolated. This haematopoietic growth factor is encoded by a unique gene specifying a messenger RNA of 1,200 nucleotides and a polypeptide of 118 amino acids. It bears no structural similarity to the functionally related factor, interleukin-3, described recently.     

Antibacterial activity in the egg mass of a sea hare

Summary The eggs of a sea hare,Aplysia kurodai, contained antibacterial factors which probably play a role in the defense of eggs against bacterial infection. The active factors were composed of several heat-labile proteins, unrelated to lysozyme, and were produced in the albumen gland.     

Plasmodium falciparum strain-specific antibody blocks binding of infected erythrocytes to amelanotic melanoma cells

An important feature of Plasmodium falciparum malaria which differentiates it from other human malarias is that erythrocytes infected with trophozoites and schizonts are not present in the peripheral blood but are sequestered along capillary and venular endothelium. Infected erythrocytes attach via parasite-induced ultrastructural modifications on the surface of the infected cells, called 'knobs'. This sequestration may be important for parasite survival because it prevents infected erythrocytes from circulating through the spleen where they could be eliminated. We have established an in vitro correlate of sequestration and used it to demonstrate that immune sera from repeatedly infected Aotus monkeys inhibit binding of infected erythrocytes to endothelial cells. We have investigated whether antiserum that blocks binding of one isolate of P. falciparum to target cells can block or reverse binding of other isolates. We report here that sera which block or reverse binding are strain-specific, indicating that the corresponding antigens on the surface of the infected erythrocytes are strain (isolate)-specific.     

Use of oven-dried blood for in vitro feeding of tsetse flies

Comparison of the survival, fecundity and offspring size of Glossina palpalis palpalis females fed reconstituted oven-dried blood, fresh, frozen/thawed, or reconstituted freeze-dried blood showed that oven-drying at 45 degrees C does not diminish the nutritional quality of blood. The significance of this finding is discussed with a view to optimizing costs and conditions of blood-diet storage and transportation in the context of mass-rearing of tsetse flies.     

Optically active benzo[c]phenanthrene diol epoxides bind extensively to adenine in DNA

Reactions of diol epoxide metabolites of carcinogenic polycyclic aromatic hydrocarbons with DNA are thought to initiate the carcinogenic process. Although formation of a benzo[a]pyrene (BaP) diol epoxide-deoxyguanosine adduct has been held responsible for biological activity, the more potent carcinogen, 7,12-dimethylbenz[a]anthracene (DMBA) binds extensively to deoxyadenosine residues in DNA, suggesting that hydrocarbon carcinogen-deoxyadenosine adducts may be instrumental in tumour initiation. Because the bay region diol epoxides of benzo[c]phenanthrene (BcPh) are very active tumour initiators, and the relative activities of the four configurationally isomeric 3,4-diol 1,2-epoxides (Fig. 1) are known, we examined their reactions with DNA. Each BcPh diol epoxide isomer exhibits a remarkable preference for covalent binding to DNA over hydrolysis, each yields a unique distribution of products with the nucleosides of DNA and each reacts extensively with deoxyadenosine residues in DNA. The relative tumour initiating activities of these stereoisomers is best reflected by the relative yields of one of the deoxyadenosine adducts formed.     

Prevention of enteral radiocesium absorption by hexacyanoferrates(II) in piglets

The efficacy of different hexacyanoferrates(II) in preventing the enteral absorption of 134Cs was studied in piglets. As compared to the controls, oral application of 134Cs together with KFe[Fe(CN)6], NH4Fe[Fe(CN)6], or Fe4[Fe(CN)6]3 resulted in a strong reduction of the 134 Cs-uptake by more than 97%. The decrease in enteral absorption depends on the dose of administered hexacyanoferrate(II), whereas differences between the compounds under study were small. The biological half-life of 134Cs in non-hexacyanoferrate(II) treated piglets was 21.6 +/- 3.3 days (mean +/- SD).     

Complementary DNA for a novel human interleukin (BSF-2) that induces B lymphocytes to produce immunoglobulin

When stimulated with antigen, B cells are influenced by T cells to proliferate and differentiate into antibody-forming cells. Since it was reported that soluble factors could replace certain functions of helper T cells in the antibody response, several different kinds of lymphokines and monokines have been reported in B-cell growth and differentiation. Among these, human B-cell differentiation factor (BCDF or BSF-2) has been shown to induce the final maturation of B cells into immunoglobulin-secreting cells. BSF-2 was purified to homogeneity and its partial NH2-terminal amino-acid sequence was determined. These studies indicated that BSF-2 is functionally and structurally unlike other known proteins. Here, we report the molecular cloning, structural analysis and functional expression of the cDNA encoding human BSF-2. The primary sequence of BSF-2 deduced from the cDNA reveals that BSF-2 is a novel interleukin consisting of 184 amino acids.