Phosphorylation in the carboxyl-terminal domain of the capsid protein of hepatitis B virus: evaluation with a monoclonal antibody.

The capsid protein of hepatitis B virus (p21c) is made of 183 amino acids coded for by the C gene. By using p21c isolated from Dane particles (hepatitis B virus) as an immunogen, a monoclonal antibody (no. 2212) which recognized an epitope dependent on the phosphorylation of p21c was raised. The binding of no. 2212 antibody to authentic p21c was completely inhibited by a synthetic undecapeptide with a sequence of RRRSQSPRRRR, representing amino acids 165 to 175 of p21c, only when the peptide was phosphorylated. Either or both of Ser-168 and Ser-170 were phosphorylated in p21c in vivo, therefore, and contributed to the manifestation of the epitope. No. 2212 antibody bound to p21c from core particles derived from Dane particles or hepatocellular carcinoma tissues (PLC/342) propagated in nude mice but did not bind to p21c from core particles expressed in Escherichia coli or yeast cells, indicating different states of phosphorylation in them. Nonphosphorylated p21c showed a higher affinity for the viral DNA than did phosphorylated p21c. Since the serum from an asymptomatic carrier, with a high titer for antibody to hepatitis B core antigen, specifically bound to phosphorylated undecapeptide (amino acids 165 to 175), the epitope would stimulate humoral antibody responses in the human host.     

Characterization of pathogenic constituents of Cryptococcus neoformans strains

We examined seven strains, comprising five serotypes, of Cryptococcus neoformans to determine what constituents of the organisms are responsible for pathogenicity and virulence in BALB/c mice. C. neoformans strains were divided into three virulence classes by survival rates after intravenous inoculation of 1 X 10(5) or 1 X 10(7) viable cells, and virulence was found not to be correlated with serotype or capsular size. C. neoformans cells resisted phagocytosis in different degrees in the presence of normal serum. Sensitivity of the C. neoformans strains to singlet oxygen ranged from resistance to susceptibility. Histological examination revealed that a weakly encapsulated virulent strain induced inflammatory responses with granuloma formation in the liver, lung, and kidney in addition to formation of cystic foci in the brain. In contrast, although the heavily encapsulated virulent strain produced granulomatous lesions in the liver, this strain preferably produced mucinous cystic foci in the lung, kidney, and brain. Correlation between virulence, and biological, histopathological and physiological evidence suggests that C. neoformans strains are endowed with the implicated multiple pathogenic constituents in various degrees and proportions. The following are suggested as the most important pathogenic constituents: a polysaccharide capsule responsible for resistance to phagocytosis and formation of cystic foci; a cell surface structure for responsible for resistance to intra- or extracellular killing and induction of the granulomatous lesion; a growth rate suitable for interacting with phagocytic elimination.     

Ultrastructure of neurofibrillary tangles in Alzheimer's disease

The ultrastructure of neurofibrillary tangles (NFT) was examined by electron microscopy. The fibrils of NFT seemed to consists of about eight protofilaments consisting of globular subunits; these protofilaments were helically wound in a longitudinal direction. The fibrils of NFT had hollow structures at their centers surrounded by the eight globular subunits. The subunits were tightly connected in the narrow parts of the fibril, but more loosely connected in the wider parts. From these findings, it seemed that the fibrils of NFT consist of a twisted tubule having periodical constrictions and is made up of eight helically wound protofilaments, forming globular subunits.     

In vitro study on release of thyroid hormone in solitary autonomously functioning thyroid nodules using cell culture method

In vitro release of thyroid hormone was investigated under basal and TSH-stimulated conditions in the solitary autonomously functioning thyroid nodules (AFTN). A small portion (0.5 g of wet weight) of the nodules and adjacent thyroid tissues removed surgically from five patients with solitary AFTN were prepared for the dispersed cell culture. In the experiment on non TSH-stimulated (basal) conditions, those culture media which were totally replaced on the 5th day after primary culture were utilized for the determination of thyroxine (T4) and triiodothyronine (T3) by radioimmunoassay. T4 and T3 levels in culture media of the functioning nodules were 1.15 +/- 0.33 microgram/dl (mean +/- SEM) and 2.72 +/- 0.68 ng/ml, contrasted with levels of 0.67 +/- 0.09 microgram/dl and 1.24 +/- 0.22 ng/ml in the paranodular tissues. The mean ratios of T3/T4 of the nodules and paranodular tissues were 0.25 +/- 0.02 and 0.19 +/- 0.02, respectively (p less than 0.05). Meanwhile, in another experiment under TSH stimulatory conditions employing 40 and 80 microU/ml of human TSH, there were no significant differences in T4 and T3 releases when the two groups were compared.     

Alpha-elastin coacervate as a protein liquid membrane: effect of pH on transmembrane potential responses.

A protein liquid membrane composed of coacervated alpha-elastin, a chemical fragmentation product of the biological elastic fiber protein, functioned as an amphoteric liquid ion-exchange membrane. Ionic permselectivities of the alpha-elastin coacervate membrane to a series of metal chlorides were investigated for the concentration-cell systems by the ordinary electrochemical measurements. Effects of pH on the transmembrane potential responses for NaCl, CaCl2, and MgCl2 systems were examined. Only in the Ca(2+)-containing system did potential responses stay at constant levels against the pH changes, whereas in the other systems, increasing pH caused potential changes, indicating an improvement of cationic permselectivity across the alpha-elastin coacervate membrane. It was suggested that the characteristic Ca2+ transport mechanisms across the alpha-elastin coacervate membrane are related in some way to the polypeptide backbone interactions specific and selective to Ca2+ ions.     

The use of arteriovenous anastomosis for replantation of the distal phalanx of the fingers.

Microvascular replantation at the distal phalangeal level has recently been reported by several authors, but as yet the rate of success has not been constant owing to the technical difficulties associated with small vessels. To solve this problem, over the last 4 years we have used arteriovenous anastomosis to reestablish either the arterial system or the venous drainage system in the 33 digits of our 23 patients. The results have been excellent, with a 91 percent success rate. Such results for replantation of the distal phalanx may be maintained and improved if a small venous graft with several branches is also utilized.     

High concentration of a gastrin releasing peptide-like immunoreactive substance in pregnant human milk

The level of a gastrin releasing peptide-like immunoreactive substance (GRP-IS) in human milk and plasma during late pregnancy and after delivery was measured. GRP-IS in milk increased during late pregnancy (1.3 nM at 39 weeks) and decreased after delivery (100 pM). GRP-IS in plasma during late pregnancy and after delivery was much lower (below 2 pM). By using HPLC and gel-filtration chromatography, two peaks of GRP-IS were purified. The one was coeluted with GRP (18-27) and the other was a prohormone. The GRP-IS in milk during pregnancy was mostly composed of proGRP. These results suggest that GRP may be produced and secreted in mammary glands.