Spacing and kinship in the Formosan squirrel living in different habitats

Summary Spacing and kinship of the Formosan squirrel, Callosciurus erythraeus thaiwanensis, were studied in two different habitats. One, native habitat in the woods of Kenting, southern Formosa, was rich in available food throughout the year and had several species of predators. The other, a site in Kamakura, central Japan where squirrels had been introduced, had relatively scanty food and few potential predators. 1. Home ranges among males and between sexes overlapped extensively in both habitats. 2. Females occupied exclusive home ranges in Kamakura but had small overlapping home ranges in Ken-ting. 3. Most males disappeared from their natal areas at 1 year old in both habitats (86% in Kamakura and 93% in Ken-ting), but less females disappeared (36% in Kamakura and 35% in Ken-ting). 4. In Kamakura, daughters settled adjacent to the mother or inherited the home range of the mother, but never shared the mother's home range. In Ken-ting, 35% of daughters shared the home range with their mothers. 5. Tolerance among female kin in Ken-ting was probably facilitated by the richness of available food throughout the year, and functioned to reduce predation risk via alarm calling and mobbing.     

Production of endothelin-1 from the mesenteric arteries of streptozotocin-induced diabetic rats

Release of endothelin-1 (ET-1) from the mesenteric arteries of Wistar rats with streptozotocin-induced diabetes (STZ-DM) rats and nondiabetic rats was measured by a specific enzyme immunoassay following purification using an immunoaffinity column. The mesenteric arteries from STZ-DM rats released a significantly higher amount of ET-1 as compared to control rats (35.8 +/- 2.8 vs 14.9 +/- 2.0 pg/1hr, p less than 0.05). The plasma level of ET-1 in STZ-DM rats was also elevated to a significant extent as compared to controls (5.1 +/- 0.4 vs 3.0 +/- 0.4 pg/ml, p less than 0.05). The systolic blood pressure of STZ-DM rats was significantly higher than of the controls (p less than 0.05). The increased level of plasma ET-1 as well as its release from the mesenteric artery of STZ-DM rats may suggest its release following damage to the endothelium caused by diabetes and/or by associated changes in blood pressure.     

Changes in aerobic and anaerobic ATP-synthesizing activities in hypoxic mouse brain

The changes in cerebral metabolism in mice in severe hypoxia were investigated by analyses of changes in the levels of energy metabolites and near-infrared spectrophotometric assessment of the states of hemoglobin and cytochrome oxidase. Under 4.4% O2, the contribution of anaerobic ATP production was at most about 20% of the demand. However, the cerebral ATP level was kept at the control level until about 1 min before death. Pentobarbital anesthesia, which reduced the cerebral rate of metabolism, prolonged the survival time, although anaerobic ATP production still did not support ATP demand. Under these conditions, deoxygenation of hemoglobin and reduction of cytochrome oxidase proceeded rapidly within 1 min. Hemoglobin reached the maximum state of deoxygenation in the middle phase of hypoxia, with no further change until death. However, cytochrome oxidase was reduced slowly with one phase of partial reoxidation due to increase of cerebral blood volume, and reached the completely reduced state at death. From these results it was concluded that the aerobic ATP synthesis, which supplied more than 80% of the cerebral demand, decreased gradually because of limitation of oxygen supply, and that the failure of oxidative phosphorylation to meet demand triggered the decrease in the cellular ATP level that led to death.     

Maternal inheritance of deleted mitochondrial DNA in a family with mitochondrial myopathy

Skeletal muscles from a mother and her daughter both with chronic progressive ophthalmoplegia were analyzed. Histological and biochemical analyses of their muscle samples showed typical features of this type of mitochondrial myopathy. Southern blot analysis revealed that, in both patients, there were two species of mitochondrial DNA (mtDNA): normal one and partially deleted one. The sizes of the deletion were different; the mutant mtDNAs from the mother and the daughter had about 2.5- and 5-kilobase deletions, respectively. The two mutant mtDNAs shared a common deleted region of 1.2-kilobase. However, both the start and the end of deletion were different between them, implying a novel mode of inheritance. This is the first report that the mutant mtDNA is responsible for the maternal inheritance of a human disease.     

Provocation of a paradoxical growth hormone response to corticotropin-releasing hormone by pretreatment with metoclopramide in patients with acromegaly and normal subjects

Two of 7 patients with acromegaly and one of 7 normal subjects exhibited a paradoxical rise in growth hormone (GH) to human corticotropin-releasing hormone (CRH) when pretreated with metoclopramide, although CRH alone did not induce an increase in GH. In one of these two patients with acromegaly, the GH increase to metoclopramide alone also reached the criteria of a paradoxical response. These two acromegalic patients showed a GH increase to metoclopramide pretreatment before and up to two months after surgery. In another acromegalic patient, whose GH level remained high 5 months after surgery, metoclopramide induced an increase in GH level, while in a patient who had an above-normal GH level 18 months after surgery, the resumption of physiological GH secretion after surgery was evidenced by a postoperative absence of a GH response to metoclopramide. It is suggested from these results that the GH response to metoclopramide and the metoclopramide-provoked GH response to CRH in patients with acromegaly result from the secretion of GH from nonadenomatous cells of the pituitary.     

Clinical significance of serum bone Gla protein and urinary gamma-Gla as biochemical markers in primary hyperparathyroidism

The serum bone Gla-protein (BGP) and urinary gamma-carboxyglutamic acid (gamma-Gla) levels were determined in patients with primary hyperparathyroidism (PHP). The mean serum BGP and urinary gamma-Gla levels were 18.6 +/- 2.34 ng/ml and 65.5 +/- 4.62 nmoles/mgCr, respectively, for the 11 patients with the skeletal type of PHP, 5.13 +/- 0.85 ng/ml and 45.2 +/- 1.33 nmoles/mgCr for the 4 with the chemical type, and 7.91 +/- 2.43 ng/ml and 43.2 +/- 3.47 nmoles/mgCr for the 5 with the renal type. Thus, patients with skeletal-type PHP had significantly higher serum BGP and urinary gamma-Gla levels than those with the other type of PHP. Serum BGP levels had significant positive correlations with serum Ca (r = 0.64, P less than 0.005), serum A1-p (r = 0.77, P less than 0.001) and serum PTH (r = 0.45, P less than 0.005). Urinary gamma-Gla levels also had significant positive correlations with serum Ca (r = 0.50, P less than 0.05), serum A1-p (r = 0.67, P less than 0.005), serum 1,25(OH)2D (r = 0.62, P less than 0.02), and serum BGP (r = 0.72, P less than 0.001). Mineral content in the left radius had significant negative correlations with serum BGP levels (r = -0.73, P less than 0.001) and urinary gamma-Gla levels (r = -0.59, P less than 0.01). As these data show, serum BGP and urinary gamma-Gla levels clearly reflect the abnormal bone metabolism and can therefore be useful biochemical markers in PHP.