[The effects of fibronectin on DNA synthesis and ultrastructure of periodontal ligament cells]

Microspectrophotometer and transmitted electron microscope (TEM) were used to study the change of DNA synthesis and ultrastructure after fibronection(FN) acted on cultured periodontal ligament cells (PDLC).The results showed that the data of nuclus area,nuclus total absorbs and nuclus mean absorbs of PDLC in FN group was higher than control(P<0.01).Under the TEM we observed that in FN group there were more euchromatin in cell nuclues and more organ cells such as microfilaments,chondriosomes and endoplasmic reticulum in cytoplasm.It suggested that FN can accelerate periodontal regeneration by promoting DNA and protein synthesis of PDLC.

[Cytological study on the effect of fibronectin in promoting periodontal regeneration]

Cell cultures and MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] colorimetric assay were used to observe the different biological effects of fibronectin (FN) on periodontal ligament (PDL) cells and gingival fibroblasts (GF). The results showed that FN has the capacity to accelerate PDL cell multiplication at dose 0.044 mumol/L, and accelerate GF multiplication at does from 0.089 mumol/L to 0.178 mumol/L. It suggests that PDL cells are more susceptible to FN than GF. So, the right amount of FN might promote the PDL cells to occupy root surface firstly and multiply, differentiate, and then to form a new connective tissue attachment.

A study on glycosylation of cationic peanut peroxidase

Cationic peroxidase from a cell suspension culture has two heterogeneously glycosylated forms, based on their Concanavalin A column binding property, namely CP-and CP+. In these two forms three out of five potential glycosylation sites are used. Asn60 and Asn185 are located in hydrophilic beta-turns, while Asn144 in a hydrophobic beta-sheet. Asn209 and Asn275 lacking glycans all have a proline residue at the C-terminal of the consensus sequence. The difference between CP- and CP+ is due to the heterogeneous glycosylation at individual glycosylation sites.

Characterization of two forms of cationic peroxidase from cultured peanut cells

Two forms of cationic peroxidase from peanut cells were differentiated by concanavalin A affinity chromatography. They differed in molecular mass as well as concanavalin A binding, leading to the initial suggestion that they represented two isozymes of peroxidase. However, similar values for the specific activity, Soret absorption, calcium content, and peptide molecular mass were observed for each of the forms. Therefore, the binding and nonbinding fractions most likely represent two molecular forms of cationic peanut peroxidase, rather than two distinct cationic isozymes. The difference between these two forms is discussed in terms of glycosylation. Through the amino acid sequence analysis of the formic acid treated peptide, the cationic isozyme has been shown to be identical in amino acid sequence to the cDNA clone PNC1.

The American, British and Dutch responses to unlinked anonymous HIV seroprevalence studies: an international comparison

With the identification of HIV as the etiological agent responsible for AIDS in 1984, it became clear that an understanding of the dimensions of the epidemic would require more than a careful detailing of the incidence and prevalence of overt symptoms of AIDS. To enable public health authorities to target and evaluate preventative interventions and plan for the health care services that would be required in the future as the infected progressed to symptomatic conditions, knowledge of the incidence and prevalence of HIV infection was critically needed.

The legality of unlinked anonymous screening for HIV infection: the U.S. approach

The purpose of this article is to describe the legal approach, and in particular, the specific statutory vehicle adopted by the U.S. with respect to unlinked anonymous screening, and to offer the U.S. approach as a possible model for those countries presently considering the implementation of unlinked HIV screening programs. Clear legal authorization for unlinked anonymous HIV testing is provided for by statute or regulation in the U.S. Federal regulations and various state laws specifically permit unlinked anonymous testing. Under these regulations and statutes, informed consent of a test subject is not required so long as testing is done for research purposes and the test results are not individually traceable to particular subjects.

A rare case of 68,XX triploidy diagnosed by amniocentesis

68,XX triploidy was found in the amniotic fluid cell culture of a 40-year-old patient. Elective termination of the pregnancy revealed a fetus with multiple congenital anomalies. While this case does show some common features with monosomy X, a greater similarity to the triploidy syndrome is observed.

Prostaglandins stimulate thyroid function in pregnant women

Intravaginal or intravenous administration of prostaglandin F(2alpha) to pregnant women produced significant elevations of plasma triiodothyronine and thyroxine concentrations, but no rise of thyrotropin. These observations are consistent with those of previous in vitro studies indicating that prostaglandins can act directly on the thyroid gland to stimulate thyroid hormone synthesis or release, or both.

VIBRIO PARAHAEMOLYTICUS–ISOLATION, IDENTIFICATION, CLASSIFICATION, AND ECOLOGY1

Vibrio parahaemolyticus was isolated from samples of water, sediment, blue crabs, oysters, and clams collected in several areas of Chesapeake Bay. Numerical taxonomy was used to identify and classify the bacterial isolates. Deoxyribonucleic acid (DNA) base composition, serology, isozyme, gas chromatography, bacteriophage sensitivity, and DNA/DNA reassociation analyses confirmed the identification and classification of V. parahaemolyticus and permitted establishment of genetic relationships of the Chesapeake Bay strains with isolates from victims of food poisoning in Japan and from samples taken in geographically diverse areas of the United States. Isolates implicated in recent outbreaks of food poisoning, the first fully documented cases of V. parahaemolyticus food poisoning in the United States, were shown by DNA/DNA reassociation measurements to be closely related to the Japanese and other isolates collected in the United States. Fatty acid profiles of cell derivatives prepared using GLC were useful in diagnosing Vibrio spp., including V. parahaemolyticus and Vibrio cholerae. Bacteriophages isolated from ocean sediments collected off Cape Hatteras were found to be active against V. cholerae and V. parahaemolyticus. Distribution of V. parahaemolyticus appears to be restricted to coastal and estuarine regions. V. parahaemolyticus has been shown to be closely associated with zooplankton and a life cycle for V. parahaemolyticus in Chesapeake Bay is proposed.