Near-Field Investigations of the Landers Earthquake Sequence, April to July 1992

The Landers earthquake, which had a moment magnitude (M(w)) of 7.3, was the largest earthquake to strike the contiguous United States in 40 years. This earthquake resulted from the rupture of five major and many minor right-lateral faults near the southern end of the eastern California shear zone, just north of the San Andreas fault. Its M(w) 6.1 preshock and M(w) 6.2 aftershock had their own aftershocks and foreshocks. Surficial geological observations are consistent with local and far-field seismologic observations of the earthquake. Large surficial offsets (as great as 6 meters) and a relatively short rupture length (85 kilometers) are consistent with seismological calculations of a high stress drop (200 bars), which is in turn consistent with an apparently long recurrence interval for these faults.

Survival of bull spermatozoa seeded and frozen at different rates in egg yolk-tris and whole milk extenders

Six factorially arranged experiments were designed to study effects of seeding, freezing, and thawing rates in whole milk and egg yolk-Tris extenders commonly used for commercial cryopreservation of bull sperm. In these extenders, semen normally is supercooled to -13 or -14 degrees C unless the sperm are seeded. When sperm were supercooled or seeded, either mechanically or with immobilized silver iodide, and frozen to -196 degrees C, the postthaw percentages of motile sperm were 59, 57, and 64%, respectively. Freezing rates of -15, -25, and -35 degrees C/min gave similar sperm survival rates and were superior to -5 degrees C/min. For milk, the critical freezing temperature extended to -75 degrees C before transfer to liquid nitrogen gave good results. For egg yolk-Tris extender, transfer to liquid nitrogen was less critical once -50 degrees C had been attained. Thawing of sperm in water baths at 25 and 45 degrees C gave similar results, and both temperatures were superior to 5 degrees C. The postthaw percentage of motile sperm in egg yolk-Tris was equal or superior to that of sperm frozen in milk. A freezing rate of -15 degrees C/min to -100 degrees C and thawing at 25 degrees C consistently gave good results.

Protein kinase C modulates parathyroid hormone- but not prostaglandin E2-mediated stimulation of cyclic AMP production via the inhibitory guanine nucleotide binding protein in UMR-106 osteosarcoma cells

In UMR-106 osteosarcoma cells we found that PTH activated both the cAMP/protein kinase A and the Ca(2+)-dependent phosphoinositide/protein kinase C (PKC) pathways, but prostaglandin E2 (PGE2) activated only the cAMP pathway. Activation of PKC by the phorbol ester PMA had no effect on cAMP production but enhanced PTH-stimulated cAMP production by 50% or more; the effect on PGE2-induced cAMP was negligible. Inhibition of the alpha-subunit of the inhibitory guanine nucleotide binding protein (Gi) by pertussis toxin pretreatment also enhanced PTH-mediated cAMP production but had no effect on PGE2-induced cAMP production. These results suggest that although PTH-mediated adenylate cyclase activity is regulated via both the stimulatory (Gs) and inhibitory (Gi) guanine nucleotide binding proteins, only Gs regulates PGE2-mediated adenylate cyclase activity in UMR-106 cells. Costimulation with pertussis toxin and PMA did not increase PTH-stimulated cAMP production above that obtained with PMA alone. This implies a similar target of action for pertussis toxin and PMA, that is, the alpha-subunit of Gi. The alpha-subunit of Gi was found to be a substrate for in vitro PKC phosphorylation of membrane fractions from UMR-106 cells, seen as a +/- 40 kD band on SDS-PAGE. Stimulation of in situ 32P-labeled cells with either PMA or PTH also enhanced incorporation of 32P into the 40 kD band. Using the peptide antisera AS/7 and EC/2, we showed that pertussis toxin-labeled subunits of both Gi1 alpha/Gi2 alpha and Gi3 alpha could be immunoprecipitated, respectively, but immunoprecipitation of membrane proteins after in situ phosphorylation and stimulation with PMA precipitated only Gi2 alpha.(ABSTRACT TRUNCATED AT 250 WORDS)

Biochemical changes in bull spermatozoa during capacitation in vitro

To evaluate the metabolic changes of bull spermatozoa (SPZ) during capacitation in vitro, SPZ were incubated for 0, 5 or 10 hours in the presence (co-culture) and absence (control) of monolayers of bovine oviduct epithelial cells, which promote capacitation-like changes in vitro. There was little change in the oxygen uptake of the SPZ after 5 hours, but after 10 hours there was a decrease, particularly in the co-cultured sample. After 5 hours there was little change in the cyclic adenosine monophosphate (cAMP) concentration of the co-culture or control SPZ, but by 10 hours the levels of cAMP decreased in both the co-cultured and control SPZ (P=0.06). The concentration of adenosine triphosphate (ATP) was somewhat decreased after 5 hours in both the co-cultured and control SPZ and the percentage of decline was much higher after 10 hours. Overall, there was no significant change in oxygen uptake or cAMP and ATP levels specifically associated with capacitation of bull SPZ.

A procedure for cryopreservation of hamster oocytes yielding highly conserved oocytes suitable for sperm penetration tests

Hamsters were superovulated and their oocytes frozen in Dulbecco's phosphate-buffered saline containing 10% fetal calf serum and 1.5 molar 1,2-propanediol. In several experiments, 94% of the hamster oocytes survived freezing and were equivalent to fresh oocytes in sperm penetration. In routine use of the procedure described, also 94% of 1,340 frozen-thawed oocytes were satisfactory for sperm penetration of several species. Frozen oocytes eliminate problems and costs of maintaining hamster colonies with variable responses on individual days.

Platelet activating factor activity in the phospholipids of bovine spermatozoa

Platelet activating factor (PAF) has been detected in sperm from several mammalian species and can affect sperm motility and fertilization. Because bovine sperm contain a high percentage of ether-linked phospholipid precursors required for PAF synthesis, a study was undertaken to determine the PAF activity of bovine sperm phospholipids. Total lipids of washed, ejaculated bull sperm were extracted, and phospholipids were fractionated by thin-layer chromatography. Individual phospholipid fractions were assayed for PAF activity on the basis of [3H]serotonin release from equine platelets. PAF activity was detected in the PAF fraction (1.84 pmol/mumol total phospholipid) and in serine/inositol (PS/PI), choline (CP), and ethanolamine phosphoglyceride (EP) and cardiolipin (CA) fractions. Activity was highest in the CP fraction (8.05 pmol/mumol total phospholipid). Incomplete resolution of PAF and neutral lipids may have contributed to the activity in the PS/PI and CA fractions, respectively. Phospholipids from nonsperm sources did not stimulate serotonin release. Platelet activation by purified PAF and by sperm phospholipid fractions was inhibited by the receptor antagonist SRI 63-675. These results indicate that bovine sperm contain PAF and that other sperm phospholipids, especially CP and EP, which are high in glycerylether components, are capable of receptor-mediated platelet activation.

Managing hypersexual disorders in brain-injured clients

Three case studies involving hypersexuality in brain-injured clients are illustrated. Two cases involved the inappropriate touching of the opposite sex, and the third case involved exhibitionism. In one case of touching, feedback was used to decrease inappropriate touching. In the other case of touching, scheduled massage was used to shift stimulus control to an appropriate setting. In the case of exhibitionism, a combination of self-monitoring, private self-stimulation and dating-skills training were used to suppress the behaviour.

Sexuality within the head-injury rehabilitation setting: a staff's perspective

A survey of 32 staff of an urban rehabilitation program for head-injured adults confirmed that sexual adjustment was an important issue for their clients, but few had pertinent training.

Social network analysis for mildly mentally retarded adults

A pilot study was conducted in preparation for an extensive analysis of the social network characteristics of mildly mentally retarded adults. From a total of 10 clients (aged 25 to 67 yr.) living in residences which were a part of the agency's supportive living program, five were administered the Arizona Social Support Interview Schedule and five were administered the Children's Inventory of Social Support. Recommendations regarding the implementation of social network analysis with mildly mentally retarded adults were discussed.

Effects of hypervitaminosis A on the bone and mineral metabolism of the rat

Vitamin A toxicity has been associated with alterations in mineral metabolism and may result in osteopenia, fractures, deformities, and growth arrest. The pathogenesis of the bone lesions that occur in vitamin A toxicity is, however, ill defined and was examined in the present study. The administration of pharmacological doses of vitamin A to growing male rats resulted in weakness and spontaneous fractures. Undecalcified bone histology of vitamin A toxic animals was characterized by increased bone resorption, osteoclastosis, a paucity of trabecular surfaces covered with osteoid, and lesions which appear to be pathognomonic of hypervitaminosis A. The serum calcium and magnesium levels of vitamin A-toxic animals were unremarkable, but serum phosphate levels were significantly higher than control values. Urinary hydroxyproline excretion reflected bone histology and was significantly increased in experimental rats. Circulating levels of the potent bone resorbers, PTH, 1,25-dihydroxyvitamin D, and 25-hydroxyvitamin D, were, however, comparable in vitamin A-toxic and control animals, suggesting a possible direct effect of vitamin A on bone. Subsequently, the effects of vitamin A (retinol) on in vitro collagen synthesis (incorporation of [3H]proline into collagen) and bone resorption (45Ca release from bone) were examined using a fetal rat calvarial culture. Retinol added to the culture medium for 20-24 h in concentrations ranging from 0.5-10 micrograms/ml selectively inhibited collagen synthesis in a dose-dependent fashion. Higher concentrations of retinol were toxic and resulted in a general inhibition of protein synthesis. Bone resorption was stimulated by 0.5 and 2.5 micrograms/ml retinol. We conclude that vitamin A toxicity in rats causes bone lesions, the genesis of which can be explained, at least in part, by a direct effect of the vitamin on skeletal tissue.

Perceiver bias in the processing of human faces: neuropsychological mechanisms

Previous research has suggested that in face-to-face contexts perceivers are biased to judge the side of the poser's face to their left as more similar to the full face than the side to their right. Traditional explanations of the perceiver bias have presumed that it is a visual field effect, with the side of the poser's face falling within the perceiver's left visual field dominating impressions of the full face. In this study, five experiments are reported. In the first experiment, the validity of the perceiver bias phenomenon was supported. The remaining experiments examined three alternative accounts of the neuropsychological processes that underlie the perceiver bias. No support was obtained for the visual field explanation, nor for an account of the bias as due to asymmetry in gaze patterns. Support was obtained for an account emphasizing a hemispatial bias in central processing. Despite equivalent intake of information from both sides of space, the brain may differentially weight information as a function of hemispatial origin. Practical and theoretical implications are discussed.

Recognition of unfamiliar faces and common objects by neurologically impaired-learning disabled and normal children

The performances of 29 normal and 29 neurologically impaired-learning disabled children (aged 7.3 to 15.3 yr.) were evaluated on unfamiliar face and common object recognition tasks. Although the normal children performed better, the relative difficulty of face and object recognition was the same for both groups.

Vitamin D metabolism in the chronic streptozotocin-induced diabetic rat

Alterations in circulating vitamin D3 metabolites have been documented in both experimental and human diabetes mellitus. Using a recirculating hepatic perfusion system and in vitro kidney mitochondrial assays, we studied vitamin D3 hydroxylation in control and insulin-deficient rats 6 weeks after the induction of streptozotocin-diabetes. Vitamin D3-25-hydroxylase activity, assessed by hepatic conversion of [3H]vitamin D3 to [3H]25-hydroxyvitamin D3 during a 4-h perfusion, was similar in diabetic and control animals. The hepatic degradation of 25-hydroxyvitamin D3 to more polar metabolites was also normal, as was glucuronide conjugation and biliary excretion of vitamin D3 metabolites. The chronic insulin-deficient state resulted in a significantly (P less than 0.01) decreased 1 alpha-hydroxylase activity and enhanced (P less than 0.001) renal 24-hydroxylase activity. These alterations in vitamin D metabolism may relate to the deranged mineral homeostasis and skeletal morphology observed in rats and humans with chronic insulin deficiency.

Calcium homeostasis in chronic streptozotocin-induced diabetes mellitus in the rat

Calcium homeostasis was studied in freely fed control, streptozotocin diabetic, long-term and short-term insulin-treated diabetic rats 7 wk after the induction of diabetes. In contrast to the short-term (5-12 day) diabetic rat model, intestinal absorption of calcium was markedly enhanced in chronically insulin-deficient animals. Moreover, conventional balance studies showed that these animals were in positive calcium balance despite severe hypercalciuria. Intestinal hyperabsorption of calcium in long-standing diabetic rats occurred despite low levels of circulating 1,25-dihydroxyvitamin D and hypercorticosteronism and was attended by hypercalcemia and suppression of both plasma parathyroid hormone (PTH) and urinary cyclic 3',5'-AMP (cAMP). Long-term insulin replacement completely normalized the intestinal hyperabsorption of calcium, corrected the plasma calcium, and significantly increased circulating PTH and urinary cAMP excretion. Insulin therapy also corrected the decreased plasma 1,25-dihydroxyvitamin D observed in untreated diabetic animals. Intestinal hyperabsorption of calcium appeared to be only partially corrected by short-term insulin therapy. The accumulated results reveal decided differences in calcium homeostasis and hormonal response between the rats with long-standing diabetes and those with diabetes of short duration.

Alkaline phosphatase activity in chronic streptozotocin-induced insulin deficiency in the rat: effect of insulin replacement

Alterations in circulating alkaline phosphatase have been described in both man and the experimental animal with chronic insulin deficiency. We evaluated plasma and tissue alkaline phosphatase levels in freely-fed control, streptozotocin-induced diabetic and insulin-treated diabetic rats, seven weeks after the induction of diabetes. Circulating alkaline phosphatase activity was markedly elevated in the insulin deficient animal (p less than 0.001) and completely normalized following insulin administration. The elevated plasma alkaline phosphatase activity observed in the insulin deficient animals was heat-resistant and phenylalanine-sensitive, a pattern typical of the intestinal isoenzyme. Small intestinal alkaline phosphatase activity was significantly higher (p less than 0.01) in the diabetic animals, but comparable in the insulin-replaced and control rats. The intestinal isoenzyme activity was found to be strikingly insulin-sensitive; withholding insulin therapy for 36 hr prior to sacrifice resulted in an abrupt rise in both plasma and intestinal alkaline phosphatase values comparable to those observed in the insulin-deficient state. In contrast to these observations, skeletal alkaline phosphatase activity was decreased in the insulin deficient animal (p less than 0.01) and this abnormality was corrected by insulin replacement. Neither insulin deficiency nor insulin replacement resulted in any significant changes in the hepatic alkaline phosphatase isoenzyme.

Alterations in circulating vitamin D metabolites in the young insulin-dependent diabetic

To assess the relationship between the decreased bone mass observed in young insulin-requiring diabetic patients and vitamin D metabolism, we measured serum 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D concentration in 45 white, insulin-dependent diabetic subjects, 7-18 yr of age. Metacarpal cortical thickness in 87% of these diabetics was below the mean for their respective ages, while 16% had a cortical thickness value greater than 2 sDs below the mean. Serum calcium and phosphate concentrations were normal, immunoreactive parathyroid hormone was in the low normal range, and total serum alkaline phosphatase was elevated compared to age- and sex-matched controls. Circulating 24,25-dihydroxyvitamin D concentrations were significantly elevated, and 1,25-dihydroxyvitamin D was significantly decreased. The increase in 24,25-dihydroxyvitamin D was greater in the diabetics with the most severe bone loss and was maximally increased during the first 5 yr of clinical diabetes. No apparent correlation was seen between metabolic control, as measured by hemoglobin A1C and urine and plasma glucose, and the circulating levels of the vitamin D metabolites. Despite appropriate insulin replacement, alterations in vitamin D metabolism occur in the young insulin-dependent diabetic and could relate to the decrease in cortical bone mass observed in these patients.

Isolated skeletal involvement in Cushing's syndrome: response to therapy

A 38-yr-old male presented with severe symptomatic osteopenia secondary to adrenal hyperfunction without any clinical expression of Cushing's syndrome. The predominantly axial distribution of his osteopenia and the presence of rib fractures healing with abundant callus formation, despite insignificant elevations in serum alkaline phosphatase, were characteristic of glucocorticoid excess syndromes. The histological features of the pretreatment bone biopsy were typical of those associated with excess glucocorticoids, namely decreased quantities of nonmineralized bone matrix, reflecting sites of bone formation, and an increase in the number of osteoclasts, indicating enhanced bone resorption. Six weeks after adrenalectomy, repeat bone biopsy revealed a marked increase in bone matrix synthesis and a significant decrease in bone resorption. These observations suggest that stimulators of skeletal turnover, like sodium fluoride, may be inappropriate in the initial treatment of steroid-induced osteopenia after surgical cure and that vitamin D and calcium therapy offers a more rational approach. Furthermore, the importance of the routine evaluation of adrenal function in any patient presenting with osteopenia is stressed, as well as the fact that relatively isolated skeletal involvement, classically described in micronodular adrenal disease, is not necessarily peculiar to a specific subset of the syndrome but may potentially attend any cause of glucocorticoid excess.