Detection of firearm imprints on the hands of suspects: effectiveness of PDT reaction.

Pyridyldiphenyl triazine (PDT) and three of its analogues were compared as practical reagents for visualizing unseen impressions left on the hands of a person who has held a firearm. The parent compound, PDT, gave the best results using intensity and clarity as measuring criteria. The effectiveness of the PDT reaction was then studied on 147 volunteers who had held firearms in their hands. Identifiable impressions of the metallic parts of the weapons were developed on the hands of 103 volunteers (70%). Results with females were slightly higher than with males, however, the difference was possibly statistically insignificant, and needs further study. Ferroprint and Ferrotrace, 5 commercial preparations that are based on the PDT reaction, have become a part of the professional equipment of every crime scene technician in Israel.

Child neglect or tragic misadventure?

The body of a 2-month-old baby was found inside the pram where he had been left overnight. Initial assessment of the event by a paramedic unit seemed to indicate foul play, based on the presence of a prominent linear pressure mark on the child's scalp and face. Thorough police and medicolegal investigation cleared the suspect and disclosed that the death resulted from accidental positional asphyxia, related to a faulty mechanism of the pram. We advise that when examining sudden unexpected death of children, forensic investigators should be aware of the potential hazards associated with baby accessories.

Hypophosphite: A Review.

Efforts to find a suitable sparing agent for nitrite in cured meat products have brought sodium hypophosphite (SHP) to the attention of the scientific community. Hypophosphites were introduced in the mid 1800s as a cure for tuberculosis, but recent reports have suggested SHP could possess antibotulinal and antimicrobial properties. Sodium hypophosphite has good potential as an antimicrobial food ingredient and it is Generally Recognized As Safe (GRAS). This review summarizes SHP chemistry, history, toxicology, regulatory status, applications, and antimicrobial properties.

Gonadotropin-releasing hormone binding and activation of enriched population of pituitary gonadotrophs.

The properties of GnRH receptors were analyzed in isolated rat pituitary cells by binding studies with the labeled GnRH agonist, [125I]iodo-[D-Ser(tBu)6]des-Gly10-GnRH-N-ethylamide. The concentration of GnRH-binding sites in pituitary cells from immature female rats was twice as high as in cells from adult females. Electron-microscopic immunocytochemistry revealed twice as many gonadotrophs in the immature rat pituitary, indicating that gonadotrophs from immature and mature female rats contain the same number of binding sites. An enriched population of gonadotrophs prepared from immature female rat pituitaries by velocity sedimentation at unit gravity contained 77% of the total radioimmunoassayable LH, and 71% of the total GnRH receptors. A second population of small, poorly granulated gonadotrophs was distributed among the cells of other fractions of the gradient, and could be detected only by immunocytochemistry. The smaller, possibly immature, gonadotrophs did not contain a measurable number of GnRH receptors. When incubated with the cells recovered from the gradient, GnRH stimulated LH release only in the mature gonadotroph-enriched fraction, and not in other regions of the gradient. These results indicate that GnRH interacts preferentially with gonadotrophs in the pituitary. The findings also suggest that functional heterogeneity exists among pituitary gonadotrophs, and that GnRH binds to and activates only the mature gonadotrophs which exhibit the highest LH-storage capacity.

Calcium-dependent actions of gonadotropin-releasing hormone on pituitary guanosine 3',5'-monophosphate production and gonadotropin release.

The effects of gonadotropin-releasing hormone (GnRH) on cGMP production and LH release in cultured rat pituitary cells are markedly dependent upon the extracellular calcium concentration. The absence of calcium from incubation media caused almost complete loss of the GnRH effects on cGMP production and LH release but did not change the stimulation of cAMP accumulation by GnRH in the pituitary of the adult male rat. In female rat pituitary cells, reduction of the extracellular calcium concentration increased the concentration of GnRH required to produce half-maximal LH release and decreased the maximal gonadotropin output but had no significant effect on basal LH release. The divalent cation ionophore A23187 stimulated LH release, and this action was dependent on extracellular calcium. Both GnRH and A23187 were found to have maximal effects when the calcium concentration was 0.6 mM, and their actions were not additive. The calcium antagonists, verapamil and lanthanum, caused concentration-dependent inhibition of the actions of GnRH, with half-maximal blockade values of 10(-5) and 3 X 10(-6) M, respectively, and had no effect on basal LH release. The binding of a radioiodinated GnRH analog, [D-Ser(t-Bu)6]des-Gly10-GnRH-N-ethylamide, to pituitary GnRH receptors was unchanged in the absence of extracellular calcium. These observations demonstrate that stimulation of pituitary cGMP production and LH release by GnRH is dependent on extracellular calcium. The site at which calcium is required during GnRH action is at a postreceptor locus before cGMP formation.

Effects of lucanthone on the sedimentation properties of DNA from HeLa cells.

Exposure of HeLa cells to lucanthone (3 microgram/ml) caused dissociation of a fast-sedimenting duplex DNA complex, as judged by lysis and sedimentation in alkaline sucrose gradients. The effect of lucanthone on the DNA complex resembled that of actinomycin D and ionizing radiation. Protein synthesis inhibitors such as cycloheximide or inhibitors of DNA synthesis such as hydroxyurea did not lead to dissociation of the complex. Lucanthone was more active than were hycanthone and five other closely related thiaxanthenones tested. Lucanthone promoted X-ray-induced denaturation of DNA in intact cells, as judged by their nuclear immunoreactivity to antinucleoside antibodies. Lucanthone did not inhibit repair of X-ray-induced DNA single-strand breaks.