Effect of ethanol on nuclear casein kinase II activity in brain

The mutual enhancement of insulin release by glucose and amino acids is not clearly understood. In this study, the effects on electrical activity and insulin release of a mixture of amino acids and glucose at concentrations found in fed (aaFD) and fasted (aaFT) animals were determined using freshly isolated mouse islets. Islets perifused with aaFD mixture showed an oscillatory pattern of electrical activity at lower glucose concentrations (5 mmol/l) than in islets perifused with the aaFT mixture and with glucose (G) alone (10 mmol/l). The concentration/response curve for the fraction of time spent by the membrane potential in the active phase in aaFD-stimulated islets was found to be significantly shifted to the left and had a smaller slope than that for glucose-stimulated islets. Insulin release followed the same pattern. This resulted in a concentration/response curve for glucose that was closer to that recorded "in vivo". We have also found that four amino acids (leucine, isoleucine, alanine and arginine) are largely responsible for the observed effects and that there is a non-linear enhancement of insulin release as a consequence of the combined effect of amino acids and glucose. This effect was more pronounced in the second phase of insulin release and was dependent on intracellular Ca2+. These findings indicate that amino acids account for most of the left-ward shift in the concentration/response curve for glucose and that a reduction in the threshold for the glucose-induced oscillatory electrical activity response and in the generation of Ca2+ spikes accounts for the triggering of insulin release at lower glucose concentrations. Nevertheless, the effects on insulin release at high glucose concentrations cannot be explained solely by the increase in glucose-induced electrical activity.     

Discarded needles do not increase soon after the opening of a needle exchange program

This study examines the effect of a Needle Exchange Program (NEP) on the quantity and geographic distribution of discarded needles on the streets of Baltimore, Maryland, and presents methods to survey discarded needles in the community. A random sample of 32 city blocks located within high-drug-use census tracts, stratified by east and west sides of the city and by proximity to the NEP, was selected for survey. Three teams surveyed the number of needles and the number of drug vials and unbroken glass bottles ("trash") to control for practice effects. Surveillance was conducted prior to initiation of the NEP in August 1994 and 1 and 2 months thereafter. Over the three study periods, the absolute count of discarded needles was 106, 130, and 128, respectively; the number of vials and bottles was 3,048, 3,825, and 3,796, respectively. The initial nonstatistically significant increase in needles (mean change = 0.38, 95% confidence interval (CI) -0.18 to 0.93) was offset by accounting for background trash. Regression models fitted with the generalized estimating equation method, which accounted for within-block correlation over time, showed no significant increase in the number of needles after adjustment for trash during the first 2 months of the NEP's operation. These data suggest that the initiation of NEPs does not result in an increase in the number of discarded needles on the street.     

Novel characteristics of a myosin isolated from mammalian retinal pigment epithelial and endothelial cells

We have isolated a novel, high Mr protein from human retinal pigment epithelial cells and endothelial cells by affinity chromatography on Sepharose 4B. Two polypeptides are present on SDS-gels of the 8 M urea eluent with apparent molecular mass of approximately 210 and 47 kDa. In the absence of dithiothreitol, the two polypeptides migrate as one protein band with an apparent molecular mass of approximately 550 kDa. "Piglet," as this molecule is tentatively named, is present in retinal pigment epithelial and endothelial cells of several species, but could not be detected in the nonepithelial cells we examined. Immunofluorescent localization using an antibody to the 210-kDa polypeptide revealed a filamentous network in the cytoplasm of cultured cells. This antibody was used to identify a cDNA for piglet in a bovine aortic endothelial cell expression library. Sequence data indicate a high degree of identity with non-muscle myosin II heavy chain. We subsequently found that piglet had an actin-activated ATPase activity, colocalized with actin in cells, and reacted on Western blots with a pan-non-muscle myosin II heavy chain antiserum. The protein was also recognized by antibodies specific for myosin heavy chain isoform A, but did not react with anti-isoform B antibodies. Although piglet has several features in common with known forms of non-muscle myosin II, the distinctly unconventional features it displays suggest that it is a novel myosin.     

Cultural assessment in home healthcare

As the nurse becomes adept at performing cultural assessments and culturally competent care, it will become clear that "although it is critical to conduct a cultural assessment with culturally and ethnically diverse groups, it is also important to realize that every client needs a cultural assessment. Every client has values, beliefs, and practices that must be considered when a clinician renders healthcare services. Therefore, cultural assessments are not limited to specific ethnic groups, but rather should be conducted on each individual" (Campinha-Bacote, 1995, p.148). Nurses who have been identified as good transcultural nurses have been found to be empathetic, caring, open, and flexible. They have a positive attitude toward cultural differences and have a genuine interest in learning from the client about the client's culture (Emerson, 1995). Talabere (1996) states that openness, appreciation of another's perspective, holistic communication, genuine interest, and a nonjudgmental attitude are central to cultural sensitivity. When a culturally sensitive nurse develops mutually agreeable goals with a patient from another culture, a kind of cultural synergy occurs, resulting in care that is "meaningful, satisfying and beneficial to clients" (Leininger, 1988, p.155).     

The genetics and evolution of handedness

At some point in hominid evolution, a mutation may have produced a "dextral" (D) allele, strongly biasing handedness in favor of the right hand and control of speech toward the left cerebral hemisphere. An alternative (chance [C]) allele is presumed directionally neutral, although there are probably other genes that influence asymmetries and that may create a weak bias toward right-handedness (and other asymmetries). Simulations show that the D allele could have spread quite quickly through a population, given even a minuscule advantage of CD heterozygotes over CC and DD homozygotes in terms of reproductive fitness. This heterozygotic advantage would also explain the apparent stability in the relative proportions of left-handers and right-handers. This putative, uniquely human allele may have emerged with the evolution of Homo sapiens in Africa some 150,000 to 200,000 years ago.     

Ruptured or intact: what can linear echoes within silicone breast implants tell us?

OBJECTIVE: During sonographic evaluation of silicone breast implants for possible rupture, we have frequently encountered several patterns of linear echoes within the implants. To our knowledge, the significance of this finding has not been established in the literature. The purpose of this study was to determine whether internal echoes are significant in predicting implant rupture. SUBJECTS AND METHODS: Thirty-three patients with 64 silicone implants were prospectively entered into a study that included gray-scale sonography of the implants and subsequent surgical removal. Echo patterns within the implants were retrospectively evaluated on hard-copy films and compared with the integrity of the implant at surgery. RESULTS: Three categories of internal echo patterns were identified: "thick linear echoes." "thin linear echoes," and "commas." One or more of these echo patterns were seen in 57 (89%) of the 64 implants. Thick linear echoes were seen in 23 (36%) of the 64 implants, thin linear echoes were seen in 33 (52%) of the 64 implants, and commas were seen in 47 (73%) of the 64 implants. All echo patterns were seen in intact and ruptured implants with nearly equal frequency. We found no statistical significance for any echo pattern in predicting whether an implant was ruptured or intact. Of the 64 implants, four were entirely free of internal echoes. All four implants were intact. CONCLUSION: A variety of linear echoes can be seen in most silicone breast implants on gray-scale sonography. The presence or absence of linear echoes is not useful in predicting implant rupture. Complete absence of internal echoes, while highly predictive of an intact implant, is infrequently seen.     

Prevalence of arterial hypertension in Cushing''s syndrome

Subacute cerebral infarcts may appear normal on T2-weighted MRI as an area isointense with surrounding normal tissue. This MRI "fogging effect" has been described in only a few cases. We present a further case of fogging observed during the evolution of a cerebellar infarct.     

Loss of GSH, oxidative stress, and decrease of intracellular pH as sequential steps in viral infection

Madin-Darby canine kidney cells infected with Sendai virus rapidly lose GSH without increase in the oxidized products. The reduced tripeptide was quantitatively recovered in the culture medium of the cells. Since the GSH loss in infected cells was not blocked by methionine, a known inhibitor of hepatocyte GSH transport, a nonspecific leakage through the plasma membrane is proposed. UV-irradiated Sendai virus gave the same results, confirming that the major loss of GSH was due to membrane perturbation upon virus fusion. Consequent to the loss of the tripeptide, an intracellular pH decrease occurred, which was due to a reversible impairment of the Na+/H+ antiporter, the main system responsible for maintaining unaltered pHi in those cells. At the end of the infection period, a rise in both pHi value and GSH content was observed, with a complete recovery in the activity of the antiporter. However, a secondary set up of oxidative stress was observed after 24 h from infection, which is the time necessary for virus budding from cells. In this case, the GSH decrease was partly due to preferential incorporation of the cysteine residue in the viral proteins and partly engaged in mixed disulfides with intracellular proteins. In conclusion, under our conditions of viral infection, oxidative stress is imposed by GSH depletion, occurring in two steps and following direct virus challenge of the cell membrane without the intervention of reactive oxygen species. These results provide a rationale for the reported, and often contradictory, mutual effects of GSH and viral infection.