Histochemical Differentiation of Anterior Pituitary Cell Types by Contrasting Azocoupling and Mucoprotein Stains

Azo compounds couple with aromatic amino-acid nuclei in the cytoplasmic proteins of human anterior pituitary acidophile and basophile cells. In acidophile cells the reaction appears to be due primarily to tyrosine, but also in part to histidine. Procedures are given for the use of naphthanil diazo blue B (tetrazotized di-ortho-anisidine), with or without a second coupling agent (H acid; 8-amino-1-naphthol-3, 6-disulfonic acid), to demonstrate acidophile cells, in contrast to mucoprotein stains (periodic acid oxidation followed by leukofuchsin or leukothionin) for the cytoplasm of basophile cells. Evans blue can also be used to give a contrasting color to basophile cells.     

Induction of mutations by 5-fluorodeoxyuridine: A mechanism of self-potentiated drug resistance?

In medium containing concentrations of deoxycytidine that occur $\text{in vivo}$, 5-fluorodeoxyuridine induced mutation frequencies 6–90 fold greater than spontaneous mutant frequencies at two genetic loci in Chinese hamster cells. In medium lacking deoxycytidine, 5-fluorodeoxyuridine was more cytotoxic but induced no mutants. Hence, the effectiveness of cancer therapy with 5-fluorodeoxyuridine may be limited by self potentiated development of 5-fluorodeoxyuridine-resistant mutants and enhanced and prolonged by manipulating deoxycytidine metabolism.     

AN IN VIVO STATHMOKINETIC STUDY OF CELL PROLIFERATION IN HUMAN GASTRIC CARCINOMA AND GASTRIC MUCOSA

Cell production rates were studied in a group of eleven patients with carcinoma of the stomach using an in vivo technique with vincristine. In normal pyloric mucosa estimates ranged from 8 to 15 cells/1000 cells/hr, and in the carcinomas from 3 to 24 cells/1000 cells/hr. Because of the very large variation in the data, comparison between individual tumours and normal mucosa is not regarded as being worth while at this stage. The implications of these results for previous human in vivo stathmokinetic experiments are also discussed.     

Treatment of cultured pancreatic B-cells with streptozotocin induces cell death by apoptosis

Treatment of cultured pancreatic B-cells (HIT-T15 and RINm5F) with the diabetogenic drug Streptozotocin resulted in a significant increase in the number of cells that became detached from the substrate during a subsequent culture period. Examination of the detached cells by fluorescence microscopy after staining with acridine orange or by electron microscopy revealed evidence of chromatin condensation and margination. Isolation and fractionation of DNA from these cells revealed a pattern of oligonucleosomal fragmentation that was not evident in untreated cells. All of these features are characteristic of entry of the cells into apoptosis and the results suggest that the diabetogenic action of Streptozotocin involves induction of apoptosis in pancreatic B-cells.     

Evaluation of fast-acquisition GPS in stationary tests and fine-scale tracking of green turtles

Fastloc GPS (FGPS) is a variant of Global Positioning System (GPS) technology that offers important new utility for investigating fine-scale movements of marine animals like green turtles that surface too briefly for effective use of standard GPS. I report here on the accuracy and efficiency of this novel technology, compare it with two alternative methods, namely boat-based ultrasonic tracking and Argos Platform Transmitter Terminals (PTTs), and provide new data on the vagility and habitat selection of green turtles in shallow coastal foraging habitat. I used a combined FGPS receiver and PTT transmitter (Sirtrack, Havelock North, New Zealand) mounted together with an ultrasonic transmitter and time-depth recorder in a tether-attached housing that allowed automatic detachment and subsequent retrieval of the equipment without the requirement to recapture turtles. With this equipment I conducted short deployments (4.5 to 16.8 d) on 3 free-living adult-size green turtles in coastal foraging habitat in Queensland, Australia. In addition, stationary tests in air and afloat were conducted at the same site. FGPS location error (mean ± SD) increased as the number of satellites used in each computation decreased, from 26 m ± 19.2 (8 satellites) to 172 m ± 317.5 (4 satellites). During live tracking the frequency of FGPS locations greatly exceeded Argos PTT, such that screened data comprised about 50 times more FGPS locations despite a much tighter screening threshold for FGPS (250 m) than for Argos PTT (1000 m). FGPS locations showed the three study turtles used modest short-term activity ranges with Minimum Convex Polygon area mean ± SD 662 ha ± 293.9. They all remained within < 4.7 km of their capture-release locations and favoured shallow water, with 86% of locations at charted depths ≤ 3 m and the deepest location at 5.9 m. Fine-scale movements of each turtle varied from day to day with respect to tortuosity and areas traversed. Statistically significant day-night differences were evident in average rates of movement (greater by day) and in habitat selection, where diurnal locations had greater seagrass density while nocturnal locations featured deeper bathymetry. Individual turtles revisited some of their centres of activity (identified from 50% fixed kernel utilisation distributions) on multiple occasions but none of the study turtles travelled consistently between the same day-night pair of sites as has been reported elsewhere. Such disparity and the day-to-day variation in movements revealed by these short-term findings highlight the need for detailed tracking over longer periods at multiple locations. Fastloc GPS technology proved an effective new tool for this area of research.     

The use of molecular and morphological characters to resolve the taxonomic identity of cryptic species: the case of Miniopterus manavi (Chiroptera, Miniopteridae)

Based on recent molecular phylogenetic studies, the Old World bat family Miniopteridae, composed of species in the genus Miniopterus , has been shown to contain complex paraphyletic species, many of which are cryptic based on convergent morphological characters. Herein we resolve the phylogenetic relationships and taxonomy of the species complex M . manavi on Madagascar and in the Comoro Archipelago, where these animals occur in different bioclimatic zones. First using mitochondrial cytochrome- b sequence data to define clades and then morphology to corroborate the molecular data, including comparisons to type specimens, we demonstrate that animals identified as this taxon are a minimum of three species: M . manavi sensu stricto occurs in at least the central portion of the Central Highlands; M . griveaudi has a broad distribution in lowland northern and central western Madagascar and the Comoros (Anjouan and Grande Comore), and M . aelleni sp. n. has been found in northern and western Madagascar and the Comoros (Anjouan). In each case, these three clades were genetically divergent and monophyletic and the taxa are diagnosable based on different external and craniodental characters. One aspect that helped to define the systematics of this group was isolation of DNA from one of the paratypes of M. manavi collected in 1896 and new topotypic material. Miniopterus manavi is most closely allied to a recently described species, M. petersoni . At several localities, M . griveaudi and M . aelleni have been found in strict sympatry, and together with M. manavi sensu stricto show considerable convergence in morphological characters, but are not immediate sister taxa. In defining and resolving the systematics of cryptic species, such as miniopterid bats, the process of defining clades with molecular tools, segregating the specimens accordingly, and identifying corroborative morphological characters has been notably efficient.     

Estimating the proportion of proliferating cells in a population.

In a population of cells that proportion which is actively engaged in the proliferative cycle is often estimated from the ratio of the observed labelling index to an expected labelling index, calculated, on the basis of all cells being in cycle, from the cell cycle phase durations and the age distribution. Ignoring the variability in cell cycle times may lead to large overestimates or underestimates in the expected labelling index. A method is given of obtaining a more accurate estimate of this variable, and hence of the proliferative proportion.