Maturity onset diabetes mellitus: response to intensive dietary management.

Analysis of the first six months of intensive dietary management of 57 maturity onset diabetics showed that a large proportion of such patients could be satisfactorily controlled without the need of either oral hypoglycaemic agents or insulin. A dietitian''s assessment of the patient''s adherence to the prescribed diet allowed groups of good and poor dieters to be selected. Among the poor dieters the plasma insulin and triglyceride levels were significantly increased though plasma glucose levels were not significantly higher. Dietary adherence may thus be an prognostic risk factor in this group of diabetic patients.     

Resolving polarized views: septin filaments do the twist

Septins are a highly conserved family of filamentous GTPases required for cell division in a wide range of eukaryotic organisms. In a recent issue of Nature, Vrabioiu and Mitchison use polarized fluorescence microscopy to show that septin filaments undergo a highly orchestrated rotation, from a longitudinal to circumferential orientation, coincident with splitting of the septin ring during cytokinesis (Vrabioiu and Mitchison, 2006).     

A new, rapid, method for preparation of dispersed pancreatic acini.

A new method for the preparation of pancreatic acini is described. The method is simple and much more rapid than previously described techniques, the time required for preparation of pancreatic acini being 20 min from removal of the pancreas. Acini prepared with this method perform in a superior manner when stimulated by either caerulein or secretin. Thus this new technique would be ideal for use in binding and secretion studies.     

Age determination by back length for African savanna elephants: extending age assessment techniques for aerial-based surveys

Determining the age of individuals in a population can lead to a better understanding of population dynamics through age structure analysis and estimation of age-specific fecundity and survival rates. Shoulder height has been used to accurately assign age to free-ranging African savanna elephants. However, back length may provide an analog measurable in aerial-based surveys. We assessed the relationship between back length and age for known-age elephants in Amboseli National Park, Kenya, and Addo Elephant National Park, South Africa. We also compared age- and sex-specific back lengths between these populations and compared adult female back lengths across 11 widely dispersed populations in five African countries. Sex-specific Von Bertalanffy growth curves provided a good fit to the back length data of known-age individuals. Based on back length, accurate ages could be assigned relatively precisely for females up to 23 years of age and males up to 17. The female back length curve allowed more precise age assignment to older females than the curve for shoulder height does, probably because of divergence between the respective growth curves. However, this did not appear to be the case for males, but the sample of known-age males was limited to ≤27 years. Age- and sex-specific back lengths were similar in Amboseli National Park and Addo Elephant National Park. Furthermore, while adult female back lengths in the three Zambian populations were generally shorter than in other populations, back lengths in the remaining eight populations did not differ significantly, in support of claims that growth patterns of African savanna elephants are similar over wide geographic regions. Thus, the growth curves presented here should allow researchers to use aerial-based surveys to assign ages to elephants with greater precision than previously possible and, therefore, to estimate population variables.     

Diapause termination and thermal requirements for postdiapause development inAphelinus mali at constant and fluctuating temperatures

Diapause termination under natural and simulated overwintering conditions, the effect of subzero temperature on postdiapause development and the relationship between postdiapause development rate and constant and fluctuating temperatures was studied in a Dutch population ofAphelinus mali Hald. (Hymenoptera: Aphelinidae).The rate of diapause termination was similar in larvae overwintering under natural and simulated conditions. Most larvae had terminated diapause by the last week of February. Some female larvae may have remained in diapause until the end of March. The exposure of postdiapause larvae to –10°C for two weeks did not affect their survival or postdiapause development rate.PostdiapauseA. mali larvae could complete development and the adults emerge from their mummified aphid hosts at constant temperatures from 12 to 24°C. Although some larvae completed postdiapause development at 10°C, few emerged. The theoretical threshold temperature (t_o) for postdiapause development was 9.4°C and the thermal constant (K) 136.4 degree-days. K was 121.4 and 134.8 for first and 50% emergence, respectively.The number of heat units accumulating above 9.4°C to 1st and 50% emergence was similar under constant and fluctuating temperatures.

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Fin de la diapause et exigences thermiques pour le développement après la diapause d'Aphelinus mali soumis à des températures constantes ou à des thermopériodes

Résumé L'achèvement de la diapause en conditions naturelles ou simulant l'hiver, les effets des températures inférieures à zéro sur le développement après la diapause et les relations entre la vitesse de développement après la diapause et les températures constantes ou en thermopériodes ont été examinés sur des populations néerlandaises d'A. mali (Hymenop.; Aphélinidae).Les taux d'achèvement de la diapause de larves hivernantes étaient semblables en conditions naturelles ou simulées. La plupart des larves ont terminé leur diapause la dernière semaine de février. Quelques larves femelles sont restées en diapause jusqu'à fin mars. L'exposition pendant 2 semaines des larves sorties de diapause à –10 °C ne compromet pas leur survie ou leur taux de développement après la diapause.Les larves ayant diapause peuvent terminer leur développement et les adultes émerger des pucerons momifiés aux températures constantes comprises entre 12 et 24 °C. Bien que quelques larves achèvent leur développement à 10 °C, peu émergent. La température seuil théorique de développement après la diapause (t_o) a été de 9,4 °C et la constante thermique (K), 136,5 degrés-jours. Pour la première émergence et pour 50% d'émergences, les valeurs de K étaient respectivement: 121,4 et 134,8.Le nombre d'unités thermiques pour la première émergence et pour 50% d'émergences était le même à température constante ou avec une thermopériode.

     

The effects of dietary fish oil on hepatic high density and low density lipoprotein receptor activities in the rat

Rats were fed either a standard ration diet or that diet supplemented with 8% by wt of a marine fish oil or safflower oil. After 10 days, plasma triacylglycerols, total cholesterol, high density lipoprotein (HDL) cholesterol, hepatic cholesterol and fatty acid synthesis and hepatic low density lipoprotein (LDL) receptor activity were significantly depressed while HDL receptor activity was significantly increased in rats fed fish oil. Fish oil-induced effects on cholesterol metabolism in the rat therefore include reciprocal changes in the activities of hepatic LDL and HDL receptors.     

Abnormalities of caerulein- and carbamylcholine-stimulated pancreatic enzyme secretion in the obese Zucker rat

The secretory function of the exocrine pancreas has been studied in dispersed pancreatic acini from obese and homozygous lean Zucker rats at 6 and 22 wk. No abnormality was found in acini from young rats. Acini from 22 wk obese and lean rats were equally responsive to secretagogues which stimulate cAMP, i.e. vasoactive intestinal peptide (VIP) and secretin. By contrast, there was a reduction in the maximum responsiveness to caerulein and carbamylcholine in acini from obese rats. These latter secretagogues act through mobilization of intracellular Ca2+. Since obese animals are insulin resistant and amylase release is modulated by insulin, the role of insulin resistance in the secretory defect was then investigated. A group of 22 wk obese rats received treatment with Ciglitazone (a drug which reduces insulin resistance in obese laboratory animals) for 4 wk before the secretion study. Despite the expected reduction in insulin resistance there was no improvement of the secretory defect seen with caerulein and carbamylcholine stimulation. Thus, the secretory abnormality in the exocrine pancreas of adult obese Zucker rats does not appear to be directly associated with insulin resistance. Furthermore, the secretory defect is linked to those secretagogues which induce Ca2+-independent phosphoinositide hydrolysis and Ca2+ mobilization in the target cell.     

Detection of renal allograft rejection by computer.

A computer program incorporating an adaptation of a statistical method, the multiprocess Kalman filter, was used to detect changes in trends of plasma creatinine and urea concentrations. In 28 recipients of renal allografts a definite deterioration in renal function was identified retrospectively on 32 occasions by an experienced renal physician independently of the statistical analysis. The computer identified 31 of these 32 episodes using creatinine and urea results, and 29 using creatinine alone. Dysfunction was identified by the computer significantly earlier (p less than 0.05) than by the clinician and a median of one day earlier (p less than 0.02) than treatment was actually initiated. The computer identified dysfunction on 11 out of 1259 days when the clinician did not suspect rejection. These 11 episodes may have had a pathological importance, though no clinical diagnosis was made. This computer method is useful for immediate analysis of incoming results and for timing events either prospectively or retrospectively.     

Role of photoperiod and temperature in the induction of overwintering pupal diapause in the spotted tentiform leafminer,Phyllonorycter blancardella

The role of photoperiod and temperature in the induction of overwintering diapause inPhyllonorycter blancardella (F.) (Lepidoptera: Gracillariidae) was examined in the laboratory and field using leafminers from commercial apple orchards in Ontario, Canada.P. blancardella exhibited a long-day response to photoperiod: long daylengths resulted in uninterrupted development whereas short daylengths induced diapause. The estimated critical photoperiod for diapause induction was L14.25∶D9.75. The larvae of leafminers destined to enter diapause took ca. 3× longer to complete development than the larvae of non-diapausing leafminers. The development prolonging effect of photoperiod decreased with decreasing daylength. Temperature modified the diapause inducing effect of photoperiod. At L14.25∶D9.75, diapause incidence was similar at 15 and 20°C but was lower at 25°C. Photoperiod also altered the normal relationship between development rate and temperature. At L14.25∶D9.75, the duration of larval development of diapausing leafminers was similar at 15, 20 and 25°C. Temperature alone is unlikely to have a role in the induction of diapause because leafminers exposed to natural late summer and fall temperature regimes and L16∶D8 did not enter diapause.