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In the eastern Pacific Ocean, three distinct forms of common bottlenose dolphin (Tursiops truncatus) have been identified, with suggestions they may be different species: a southern California/Mexico coastal, a northern temperate offshore, and an eastern tropical Pacific (ETP) offshore form. Currently, only one species (T. truncatus) is recognized in the region, with the first two forms described as distinct ecotypes. The goal of this study was to improve our understanding of the taxonomic status of these previously described forms through a re-examination of their morphological differentiation. We analyzed 135 skulls from the eastern and western Pacific, including the two nominal species, T. gillii and T. nuuanu, previously described for the eastern North Pacific and ETP, respectively. Additionally, we examined the holotypes of two currently recognized species in the genus, T. truncatus and T. aduncus. Our results showed significant morphological differentiation among bottlenose dolphins in the Pacific Ocean. The ETP offshore bottlenose dolphins were smaller in skull and body size and diagnostically distinct from dolphins in the western North Pacific and other regions in the eastern Pacific. Our results also indicated that, while other bottlenose dolphins in the Pacific were more similar to the globally distributed T. truncatus, the ETP offshore dolphins shared similarities with a previously described species in that region. The distinct environmental conditions in the ETP may be driving the evolutionary differentiation of these bottlenose dolphins. Given these results, we here recommend the recognition of ETP offshore bottlenose dolphins as a distinct subspecies, Tursiops truncatus nuuanu. [ABSTRACT FROM AUTHOR]

Pancreatic islet cells from pigs (3-12 days old) were maintained in monolayer culture at 37 °C for > 30 days. Cultures were maintained in enriched Medium 199 with 5% fetal calf serum and with the glucose concentration being cycled between 11.10 and 27.75 mmol/l every 2 days. The presence of B cells in the cultures was demonstrated by insulin secretion into the culture medium, cell staining with aldehyde fuchsin and immunofluorescence. A cells in the cultures were monitored by glucagon secretion into the medium. The absence of exocrine cells was determined by the inability to detect α-amylase in the culture medium. Insulin secretion determined over a 34-day period, was found to diminish after 12 days in culture. The fall in levels of extractable B cell insulin with time correlated with the levels of insulin secreted into the medium. Response to short term glucose stimulation (2 h in serum-free medium) was determined on days 6, 10 and 12 in culture. Morphological changes appeared after 25 days in culture, although on day 33 insulin secretion was 62.5 μU · culture · day. DNA synthesis (determined by H-thymidine incorporation and autoradiography) was demonstrated (day 12, 39.4±0.9 labelled cells/culture). These findings suggest that pig islet cell monolayer cultures are a useful tool for morphological and biochemical studies and that neonatal pig islets are a potential source of material for transplantation. [ABSTRACT FROM AUTHOR]

Fluorescein-labeled antibody against human uterine actomyosin was used as a histochemical stain to identify and localize myoepithelial cells during the early stages of differentiation of the rat submandibular gland. Smooth muscle and myoepithelium of the rat in tissue sections reacted specifically with the antiserum, indicating close antigenic relationship between smooth muscle proteins of these two species. At birth the rat submandibular gland has neither acini nor myoepithelial cells, but by 24 hours after birth a few positively fluorescent cells in the characteristic position of myoepithelium were identified around the terminal tubules. By 1 week they had formed an extensive network around the terminal tubular structures, and from the first until the fifth week continued gradually to increase in number, reaching approximately the adult number and distribution. Alkaline phosphatase is not present in detectable amounts in myoepithelial cells until the third postnatal day. From then until the fifth week alkaline phosphatase localization demonstrates a developmental pattern of myoepithelial cells similar to that shown by immunofluorescence methods. The appearance of these cells in the early postnatal period suggests that they play a functional role in the movement of secretions in the immature gland. Although the origin of myoepithelial cells remains unknown, differentiation from uncommitted cells within the terminal tubule, or migration of cells from a position external to the basement membrane are suggested as possible modes of development. [ABSTRACT FROM AUTHOR]