Identified taste bud cell proliferation in the perihatching chick [published erratum appears in Chem Senses 1998 Aug;23(4):459]

Developing taste buds in the anterior mandibular floor of perihatching chicks were studied by high voltage electron microscopic autoradiography in order to identify proliferating gemmal cell types. Montaged profiles of 29 taste buds in five cases euthanized between embryonic day 21 and posthatching day 2 were analyzed after a single [3H]thymidine injection administered on embryonic day 16, 17 or 18. Results showed that dark cells comprised 55% of identified (n = 900 cells) and 62% of labeled (n = 568 cells) gemmal cells as compared with light, intermediate, basal or perigemmal bud cells. Dark cells had both a greater (P < 0.05) number of labeled cells and a greater amount of label (grains/nucleus) than the other four bud cell types, irrespective of injection day. The nuclear area (micron 2) of dark cells was not significantly larger (P > 0.05) than that of the other gemmal cell types and therefore cannot account for the greater amount for label in the dark cells. Interestingly, only dark cells showed a positive correlation (P < 0.003) between amount of label and nuclear area. Results suggest that, during the perihatching period of robust cell proliferation, dividing dark cells may give rise primarily, but not exclusively, to dark cell progeny.      

Action of lysosomal phospholipase A1 on bis(monoacylglycerol)phosphate.

Bis(monoacylglycerol)phosphate (BMP) in macrophages is known to rapidly turn over its acyl moiety(s) located at primary positions of the glycerols, yet the glycerols and phosphate remain stable within the BMP molecule. Here we examine whether the phospholipase A1 isolated from rat-liver lysosomes is capable of deacylating BMP. By comparison with the precursor of BMP, phosphatidylglycerol, BMP is a very poor substrate for the phospholipase A1. We conclude, therefore, that a direct deacylation of the acyl groups at the primary alcohol level of the glycerol probably does not occur, but postulate that transacylations may occur to account for the removal of the acyl moiety.     

Inter-strain comparison by pyrolysis mass spectrometry of Staphylococcus aureus isolates associated with nosocomial infection

Pyrolysis mass spectrometry was used to characterise Staphylococcus aureus isolates from an outbreak of post-operative wound infections on a mixed surgical ward. The PyMS results were compared with those of phage typing. Both suggested a single strain of S. aureus, of phage type 3C, 55,71, was responsible for six of the 13 wound infections. PyMS differentiated an isolate from a member of staff of similar phage type to the epidemic strain, which had previously been considered to be the point source for the outbreak. PyMS is a rapid and inexpensive technique for investigating nosocomial outbreaks, including those caused by S. aureus and, in this instance, was more discriminatory than phage typing.     

Long-term results of [131I]metaiodobenzylguanidine treatment of refractory advanced neuroblastoma.

Fourteen patients with advanced neuroblastoma, which was unresponsive to or had relapsed despite conventional therapy, were entered into a phase I/II trial of [131I]metaiodobenzylguanidine (131I-MIBG). Doses ranged from 1.85-8.14 GBq each (50-220 mCi), with cumulative doses of 1.85-24.20 GBq (50-654 mCi) in one to three doses. Side effects included mild nausea and vomiting and moderate myelosuppression which occurred in nine patients. Subjective responses occurred in five patients. Four patients had objective responses (one partial, two minor and one mixed). Two of these patients remain alive 80 and 60 months after beginning 131I-MIBG therapy. Comparison of the 131I-MIBG treated patients with 11 carefully matched control patients treated with an advanced current chemotherapy protocol (CCG 8605) was performed by means of Kaplan-Meier life table analysis. The 14% four-year survival with 131I-MIBG compared favorably with the 6% achieved by salvage chemotherapy. We thus believe 131I-MIBG may have a role in the management of neuroblastoma.