Geographical patterns of persistence in duck guilds

Geographical gradients of persistence in community structure have been suggested to be causally related to underlying gradients of species diversity, environmental variability and/or productivity. In order to test whether the persistence of breeding duck communities was dependent on any one of these three factors, thirty-three years of census data from the Canadian prairie and boreal forest regions was examined along geographical gradients of wetland habitat variability and productivity. For breeding ducks, locally derived patterns of persistence were generally independent of local habitat conditions. Persistence appeared to be related more to patterns of emigration and immigration in response to climatic conditions (i.e., drought) in the southern prairies than to local species richness, wetland habitat variability or productivity. It is suggested, therefore, that analyses of community persistence derived at small spatial scales may be of limited value if the structure of communities is not regulated by local conditions.     

A decade of diabetes: keeping children out of hospital.

OBJECTIVES--To document the number of children aged less than 15 years who developed diabetes and were managed within one large health district, and to evaluate the outcome of those children managed without hospital admission at diagnosis. DESIGN--A retrospective study over 1979-88, when a paediatrician and a physician with special interests in childhood diabetes initiated joint clinics. Data collected from the district diabetes register and files of consultants and health visitors specialising in diabetes. SETTING--Referral of children to consultants in Leicestershire (total population 863,000). MAIN OUTCOME MEASURES--The proportion of children managed without hospital admission, comparison of readmission rates and glycated haemoglobin concentrations between children admitted and those not admitted. RESULTS--Over 10 years 236 children aged 10-14 years developed diabetes (annual incidence rate 12.8/100,000 child population (95% confidence interval 11.3 to 14.7)). In total 138 were not admitted to hospital but received supervised management based at home. Admitted children were younger or acidotic or their family doctors did not contact the diabetes team. Duration of admission declined from seven days in 1979-80 to three days in 1987-8. Ninety two were not admitted to hospital during the 10 years for any reason. Significantly fewer children who received management at home were readmitted for reasons related to diabetes than the group treated in hospital (30 (22%) v 40 (41%); p = 0.004). Concentrations of glycated haemoglobin were no different between the two groups. CONCLUSIONS--Children with newly diagnosed diabetes may be safely and effectively managed out of hospital. Domiciliary or community based management depends on the commitment of consultants specialising in diabetes working in close cooperation with general practitioners, specialist nurses in diabetes, and dietitians.     

A- and B-type lamins are differentially expressed in normal human tissues

 A selection of normal human tissues was investigated for the presence of lamins B1, B2, and A-type lamins, using a panel of antibodies specific for the individual lamin subtypes. By use of immunoprecipitation and two-dimensional immunoblotting techniques we demonstrated that these antibodies do not cross-react with other lamin subtypes and that a range of different phosphorylation isoforms is recognized by each antibody. The lamin B2 antibodies appeared to decorate the nuclear lamina in all tissues examined, except hepatocytes, in which very little lamin B2 expression was observed. In contrast to previous studies, which suggested the ubiquitous expression of lamin B1 in mammalian tissues, we show that lamin B1 is not as universally distributed throughout normal human tissues as was to be expected from previous studies. Muscle and connective tissues are negative, while in epithelial cells lamin B1 seemed to be preferentially detected in proliferating cells. These results correspond well with those obtained for lamin B1 in chicken tissues. The expression of A-type lamins is most prominent in well-differentiated epithelial cells. Relatively undifferentiated and proliferating cells in epithelia showed a clearly reduced expression of A-type lamins. Furthermore, most cells of neuroendocrine origin as well as most hematopoietic cells were negative for A-type lamin antibodies. Accepted: 4 February 1997     

Thyroglobulin biosynthesis in a larval (ammocoete) and adult freshwater lamprey (Lampetra planeri Bl.).

1. The biosynthesis of 18-19S thyroglobulin has been studied in a larval and adult freshwater lamprey (Lampetra planeri Bl.). 2. In vivo and in vitro experiments have been performed by injecting into the coelomic cavity or by incubating branchial region labeled constituents of Tg of higher vertebrates (125I, [3H]leucine and various [3H]carbohydrates). 3. Larvae (ammocoetes) and adults incorporate all labels into thyroglobulin (18-19S Tg), containing a small proportion of labeled T3 and T4, as identified by paper chromatography, and very minute amounts of stable iodine. 4. In adults, the biosynthesis of 18-19S Tg proceeds much more rapidly and the labels are incorporated in higher percentage than in larvae. 5. The demonstration of the biosynthesis of the specific thyroid protein, 18-19S Tg, in larvae indicates that the biochemical mechanism of hormonogenesis is present in larval endostyle before the morphological differentiation of thyroid cells and follicles occurring during metamorphosis. 6. Some 18-19S Tg is apparently stored in the endostyle.