The insulin secretory response by pancreatic ␤-cells to an acute "square wave" stimulation by glucose is characterized by a first phase that occurs promptly after exposure to glucose, followed by a decrease to a nadir, and a prolonged second phase. The first phase of release is due to the ATP-sensitive K ؉ (K ATP ) channel-dependent (triggering) pathway that increases [Ca 2؉ ] i and has been thought to discharge the granules from a "readily releasable pool." It follows that the second phase entails the preparation of granules for release, perhaps including translocation and priming for fusion competency before exocytosis. The pathways responsible for the second phase include the K ATP channel-dependent pathway because of the need for elevated [Ca 2؉ ] i and additional signals from K ATP channel-independent pathways. The mechanisms underlying these additional signals are unknown. Current hypotheses include increased cytosolic long-chain acyl-CoA, the pyruvatemalate shuttle, glutamate export from mitochondria, and an increased ATP/ADP ratio. In mouse islets, the ␤-cell contains some 13,000 granules, of which ϳ100 are in a "readily releasable" pool. Rates of granule release are slow, e.g., one every 3 s, even at the peak of the first phase of glucose-stimulated release. As both phases of glucose-stimulated insulin secretion can be enhanced by agents such as glucagon-like peptide 1, which increases cyclic AMP levels and protein kinase A activity, or acetylcholine, which increases diacylglycerol levels and protein kinase C activity, a single "readily releasable pool" hypothesis is an inadequate explanation for insulin secretion. Multiple pools available for rapid release or rapid conversion of granules to a rapidly releasable state are required. Diabetes 51 (Suppl. 1):S83-S90, 2002

Case records of 36 dogs with confirmed leptospirosis diagnosed at the New York State College of Veterinary Medicine from 1980 to 1995 were reviewed retrospectively, and clinical, serological and pathological findings were recorded to characterise the epidemiology of this disease in upstate New York. Titres were directed predominantly against serovars grippotyphosa and/or pomona in 31 of 34 dogs. Convalescent titres were measured for 53 per cent of dogs. The most common clinical presentation was acute renal failure. Increased liver enzyme activity was documented in 22 of 36 dogs. It is clear from this study that Leptospira pomona and grippotyphosa are important pathogens capable of causing severe renal and hepatic injury in dogs.

Insulin secretion has been studied in isolated rat pancreatic islets under stringent Ca2l-depleted, Ca2+-free conditions. Under these conditions, the effect of 16.7 mM glucose to stimulate insulin release was abolished. Forskolin, which activates adenylyl cyclase, also failed to stimulate release in the presence of either low or high glucose concen- (6, 7). Another important effect of glucose with an enhancing effect on insulin release is time-dependent potentiation. This pathway too is Ca2+ dependent (14). In contrast to these Ca2+-dependent effects, we report here the existence of an interesting Ca2+-independent effect of glucose to augment insulin secretion when protein kinase C (PKC) is activated in the f3 cell. Furthermore, when protein kinase A (PKA) and PKC are activated simultaneously, this Ca2+-independent augmentation of insulin release is of large magnitude. MATERIALS AND METHODSIsolation of Pancreatic Islets and Insulin Secretion. Pancreatic islets were isolated from adult male Sprague-Dawley rats by collagenase dispersion as described (6, 15). Insulin release was measured under both static incubation and perifusion conditions. In static incubations, batches of five size-matched islets were incubated in 1 ml of Krebs-Ringer bicarbonate (KRB) buffer containing 129 mM NaCl, 5 mM NaHCO3, 4.8 mM KCl, 1.2 mM KH2PO4, 2.5 mM CaCl2, 1.2 mM MgSO4, 2.8 mM glucose, 0.1% bovine serum albumin, and 10 mM Hepes (pH 7.4) for 60 min at 37°C (preincubation). Then the incubation medium was removed by aspiration and 1 ml of fresh KRB buffer containing test substances was introduced. Incubation under the test conditions was then continued for 30 or 60 min at 37°C. At the end of the incubations, the medium was aspirated and kept at -200C until radioimmunoassayed for insulin. Rat insulin was used as a standard for radioimmunoassay. When Ca2+-depleted conditions were needed, KRB buffer devoid of Ca2+ with different concentrations of EGTA was used throughout the experiments (for washing the islets and both the 60-min preincubation and the 60-min experimental incubation). When nitrendipine and thapsigargin were used, they were present throughout the preincubation and incubation periods. When norepinephrine was used, it was present during experimental incubation periods only. In perifusion experiments, 25 size-matched islets were placed in each 0.7-ml perifusion chamber (16,17) The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.