Anti-Hepatitis A Virus Antibody Response Elicited in Mice by Different Forms of a Synthetic VP1 Peptide

Peptide VP1 (11-25) of the capsid of hepatitis A virus was synthesized by the Fmoc-polyamide solid phase method, and administered to mice in different forms: (1) free, (2) encapsulated in multilamellar liposomes, (3) coupled to keyhole limpet hemocyanin (KHL), and (4) incorporated into a tetrameric branched lysine core. The highest anti-VP1 peptide responses were generated by synthetic peptides entrapped into liposomes and coupled to KLH. No anti-HAV response was generated with the free peptide, while all the other forms induced both anti-HAV and HAV-neutralizing antibodies. Maximum neutralization indices were observed in ascites from mice treated with liposome-entrapped and KLH peptides.     

Composition and properties of Albizia lebbeck gum exudate

An analytical study has been made of six gum specimens from Albizia lebbeck, Leguminosae. Galactose, mannose, arabinose, glucuronic acid and its 4-O--metyl analogue are present in all the specimens studied. Rhamnose was not detected according to sugar analysis and spectral data. The absence of this sugar, the high acidity and the relatively low limit viscosity number contrast with the values reported previously for one African sample of A. lebbeck. The lead content is much higher than that recorded for other Albizia gums. ¹³C-NMR spectrum of this gum, in deuterium oxide, shows good resolution.     

Transferable clastogenic activity in plasma from patients with Fanconi anemia

The present study was conducted on 13 patients with Fanconi anemia, 25 parents and 12 siblings. The chromosomal instability characteristic of this congenital breakage syndrome was associated with the presence of transferable clastogenic material in the plasma, as also reported previously for ataxia telangiectasia and Bloom's syndrome. While all plasma ultrafiltrates from homozygotes had chromosome damaging properties, the clastogenic material had to be concentrated in most heterozygotes to reach detectable levels. The clastogenic effect was exerted via the intermediacy of superoxide radicals, since it was regularly inhibited by superoxide dismutase (SOD). This adds further evidence for a prooxidant state in this hereditary disease. The autosustained clastogenic activity possibly plays a role in the progressive impairment of blood cell-producing bone marrow and may predispose patients to develop cancer and leukemia. Prophylactic use of antioxidants may be recommended, using clastogenic plasma activity as a guide.     

Hemagglutination properties of Enterococcus

In total, 86 enterococcal strains including representatives of most of the described species were tested for the ability to agglutinate human, sheep, and rabbit erythrocytes. Five strains did not react with any of the erythrocytes tested, and 81 (94.2%) strains agglutinated only rabbit erythrocytes. The hemagglutination titers ranged from 2 to 64. Loss of the hemagglutination activity was observed when rabbit erythrocytes were treated with trypsin or neuraminidase. Trypsin treatment of the bacterial suspensions also caused loss of the agglutination ability. On the other hand, heat treatment of bacterial suspensions increased the efficiency of the interactions, and higher titers were obtained. Assays for inhibition of hemagglutination were performed with -d-fucose, -d-galactose, -d-galactose, d-glucose, N-acetyl-galactosamine, N-acetyl-glucosamine, N-acetylneuraminic acid, N-acetylneuraminic acid-lactose, and fetuin. Only fetuin was able to inhibit the hemagglutination reactions. The results showed that hemagglutination properties are common to the different enterococcal species tested. They also suggest that enterococci possess hemagglutinins of proteic and non-proteic nature that are involved in the attachment to sialic acid-containing receptors on the surface of rabbit erythrocytes.     

Gating of gap junction channels.

Gap junctional conductance ( gj ) in various species is gated by voltage and intracellular pH (pHi). In amphibian embryos, gj is reduced to half by a 14 mV transjunctional voltage ( Vj ), a change that in fish embryo requires approximately 28 mV. Crayfish septate axon and pairs of dissociated rat myocytes show no voltage dependence of gj over a range of Vj greater than +/- 50 mV. In fish and amphibian blastomeres , gj is steeply decreased by decrease in pHi (n, Hill coefficient: 4.5) and the apparent pKH (7.3) is in the physiological range. In crayfish septate axon the pKH is lower (6.7) and the curve is less steep (n = 2.7). Rises in cytoplasmic Ca can also decrease gj but much higher concentrations are required (greater than 0.1 mM in fish blastomeres). Voltage and pH gates on gap junctions in amphibian embryos appear independent. In squid blastomeres pH gates exhibit some sensitivity to potential, both transjunctional and between inside and outside. A pharmacology of gap junctions is being developed: certain agents block gj directly (aldehydes, alcohols, NEM in crayfish); others block by decreasing pHi (esters that are hydrolyzed by intrinsic esterases, NEM in vertebrates, and, as in the experiments demonstrating the effect of pHi, weak acids). Certain agents block pH sensitivity without affecting voltage dependence (retinoic acid, glutaraldehyde, EEDQ), further indicating separateness of pH and voltage gates. These studies demonstrate a dynamics of gap junctional conductance and variability in gating in a series of possibly homologous membrane channels.     

Nodular pulmonary amyloidosis.

An elderly man had a 10-year history of multiple pulmonary nodules that he had refused to have investigated. He died of a ruptured abdominal aortic aneurysm. At autopsy the nodules were shown to consist of amyloid. There was no evidence of systemic amyloidosis.     

Lack of effect of toxic aluminium concentrations on nitrogen fixation by nodulatedStylosanthes species

Summary Effects of three solution aluminium concentrations (0, 25, and 100M) on nitrogen fixation by well-nodulated plants ofStylosanthes hamata, Stylosanthes humilis andStylosanthes scabra are reported. Plants were inoculated with Rhizobium CB756 and grown for 21 days in an aluminium-free nutrient solution at pH 5.3 before imposition of the aluminium treatments.Nitrogen fixation was measured both by the increase in total nitrogen content of the plants and acetylene reduction in roots of plants harvested at 10 and 20 days after imposition of the aluminium treatments. Solution aluminium concentrations as high as 100M, had no detrimental effect on nitrogen fixation in any species.     

Pelvic visceral arteries of rabbits (Oryctolagus cuniculus)]

40 pelvic preparations of rabbits (oryctolagus cuniculus) were bilaterally studied by dissection under the stereomicroscope and angiography. The arterial pattern of the pelvis, i.e. origin and branching of the umbilical, urogenital and internal pudendal arteries (visceral branches), is described. The main characteristics observed are as follows: (1) The umbilical artery is permeable in adults and gives origin to the cranial vesical artery and a caudal branch that irrigates the pelvic urogenital organs and, eventually, the rectum, with six patterns of branching in both sexes. (2) Usually, the urogenital artery is the continuation of the visceral branch of the internal iliac artery. In 1 animal, unilaterally, it arises from the median sacral artery. In 12 animals (6 bilaterally and 6 unilaterally) the urogenital artery is absent. When present, it forms two branches, a cranial and a caudal one, that irrigate of the urogenital organs in both sexes. (3) The internal pudendal artery is the direct continuation of the internal iliac artery and gives to rise to some visceral branches that irrigate the penis, bulbourethral gland and rectum (with six patterns of branching) in males, and the vagina, clitoris and rectum (with three patterns of branching) in females.     

Effect of temperature on the reversal of the calcium ion pump in sarcoplasmic reticulum.

Sarcoplasmic-reticulum vesicles were actively loaded with Ca2+ in the presence of phosphate, and the ADP-induced Ca2+ efflux and ATP synthesis were measured as a function of temperature. Arrhenius plots show break points for both processes at about 18 and 37 degrees C. Between 18 and 37 degrees C, Ca2+ efflux and ATP synthesis occur with an activation energy of 67.2-71.4 kJ/mol, whereas it is about 189-210 kJ/mol for temperatures below 18 degrees C. Above 37 degrees C, the rates of ADP-induced Ca2+ release and of ATP synthesis sharply decline until the temperature reaches about 42 degrees C. Above this temperature, the Ca2+ efflux increases again even in absence of ADP, although the synthesis of ATP is inhibited, which reflects leakiness of the vesicles. The results show that the transition temperatures for ADP-induced Ca2+ efflux and for ATP synthesis resemble those for active Ca2+ uptake, which indicates that the same coupling mechanism is involved during the inward and outward Ca2+ translocations across the membrane.     

Fluxes of Ca2+, Sr2+ and Mg2+ in synaptosomes.

Synaptosomes isolated from sheep brain cortex accumulate Ca²⁺, Sr²⁺ and Mg²⁺ when incubated in isosmotic sucrose media containing 5 mM of either of these cations. The maximal levels of cations retained per mg of protein are 100 nmol of Ca²⁺, 85 nmol of Mg²⁺ and 80 nmol of Sr²⁺. The loss of Ca²⁺ or Sr²⁺ from the preloaded synaptosomes is increased by monovalent cations in the following order: Na⁺> K⁺ > Li⁺> choline, whereas for the loss of Mg²⁺ this order is different: K⁺ > Na⁺ > Li ～ choline. The efflux of Ca²⁺ or Sr²⁺ induced by monovalent cations decreases as the temperature is lowered and it is nearly abolished at 0°C, whereas the efflux of Mg²⁺ is much less influenced by temperature. The results suggest that the mechanism of exchange of Ca²⁺ for Na⁺ in synaptosomes operates similarly for Sr²⁺, but not for Mg²⁺.