Convergent and alternative designs in the digital adhesive pads of scincid lizards.

Prasinohaema virens, an arboreal scincid lizard, differs from its closest relatives in that it exhibits subdigital adhesive setae resembling those of anoles in shape and those of geckos in some aspects of size. The other scincid species in this genus as well as those in a presumed ancestral genus exhibit pad scales with surface folds and ruffles but no setae; at least one of these species uses an adhesive grip similar to that of anoles and geckos. Thus, there appear to be two strikingly different epidermal specializations for adhesive grip within this small radiation.

Fission in the evolution of a lizard karyotype.

The lizard Anolis monticola has a diploid chromosome number of 48 (24 macrochromosomes and 24 micrcchromosomes). More primitive members of the genus, as determined by bone morphology, have 12 macrochromosomes and 24 microchromosomes. Since the higher chromosome number is the derived condition, this is a case of karyotypic change by centric fission.

Cardioprotective Effects of Curcumin-Nisin Based Poly Lactic Acid Nanoparticle on Myocardial Infarction in Guinea Pigs.

Myocardial infarction (MI) is the most prevalent cause of cardiovascular death. A possible way of preventing MI maybe by dietary supplements. The present study was thus designed to ascertain the cardio-protective effect of a formulated curcumin and nisin based poly lactic acid nanoparticle (CurNisNp) on isoproterenol (ISO) induced MI in guinea pigs. Animals were pretreated for 7 days as follows; Groups A and B animals were given 0.5 mL/kg of normal saline, group C metoprolol (2 mg/kg), groups D and E CurNisNp 10 and 21 mg/kg respectively (n = 5). MI was induced on the 7th day in groups B-E animals. On the 9th day electrocardiogram (ECG) was recorded, blood samples and tissue biopsies were collected for analyses. Toxicity studies on CurNisNp were carried out. MI induction caused atrial fibrillation which was prevented by pretreatment of metoprolol or CurNisNp. MI induction was also associated with increased expressions of cardiac troponin I (CTnI) and kidney injury molecule-1 (KIM-1) which were significantly reduced in guinea pig's pretreated with metoprolol or CurNisNp (P < 0.05). The LC50 of CurNisNp was 3258.2 µg/mL. This study demonstrated that the formulated curcumin-nisin based nanoparticle confers a significant level of cardio-protection in the guinea pig and is nontoxic.

The role of alterations in membrane lipid composition in enabling physiological adaptation of organisms to their physical environment.

It is clear from the literature reviewed that modifications in membrane lipid composition play a major role in the adaptation of diverse organisms to specific environments and physiological circumstances. Acyl chain and molecular species restructuring in phospholipids are the most ubiquitous adaptations to environmental insult, being implicated in membrane adjustments to temperature, pressure, water activity, pH and salinity. In contrast, other adaptations (e.g. modulation of anionic phospholipids (salinity adaptation), trehalose content (dehydration) and the PC/PE ratio (temperature acclimation] appear to be more context specific. Although the volume of correlative data relating membrane composition to environmental state is impressive, several questions must be explicitly addressed in future research if a mechanistic understanding of the role of lipids in fine tuning membrane function is to be achieved. These include: (1) Adaptation thresholds--How much environmental variation is required before an acclimatory response is initiated, and is the extent of membrane perturbation induced by such minimally effective stimuli similar for different stress vectors? Interspecific comparisons of the Na+/K(+)-ATPase of fish collected at different depths indicate that species must be separated in depth by a distance corresponding to a pressure difference of 20 MPa before pressure adaptation is evident. Assuming a dT/dP value of 0.23 (Table 1), a 20 MPa change in pressure corresponds to ca. a 5 degrees C change in temperature, which agrees well with the minimal temperature change required to elicit changes in the lipid composition of plasma membranes in kidney tissue of thermally-acclimating trout. A pressure of 20 MPa also corresponds approximately to the maximum depth from which deep sea animals survive being brought to the surface. Collectively, these observations suggest that the minimally effective stimuli for both temperature and pressure adaptation are similar. Comparable data are not available for other environmental variables. (2) Signal transduction--What signals are being sensed and how are they transduced into an adaptational response? In some cases, it is clear that the enzymes of lipid metabolism respond directly (either by a variation in catalytic rate or substrate preference) to variations in the physical environment in an apparently adaptive manner (e.g. refer Sections VI.A.1 and VI.B.2). It seems unlikely, however, that such direct effects can explain the totality of the adaptive capacity of organisms, especially given the evidence for the induction of desaturase synthesis in cold adaptation (refer to Section VI.A.2).(ABSTRACT TRUNCATED AT 400 WORDS)

Docosahexaenoic acid (DHA) alters the structure and composition of membranous vesicles exfoliated from the surface of a murine leukemia cell line.

Membrane lipid microdomains are regions of the membrane thought to be functionally important, but which have remained poorly characterized because they have proven to be difficult to isolate. The exfoliation of small membranous vesicles from the cell surface is a continuous and normal activity in many cells. If microdomains are relatively large or stable, they may influence the structure and composition of exfoliated vesicles, which are easy to isolate. We tested the ability of docosahexaenoic acid (DHA), a fatty acid proposed to alter the structure of microdomains, to change the structure and composition of vesicles exfoliated from a murine leukemia cell line. Cells were cultured in normal and DHA-enriched media for 72 h, then washed and given a 15-h exfoliation period. Afterwards, the pooled vesicles and their parent plasma membrane were collected and analyzed. Vesicles and plasma membrane from cells grown in normal culture medium had similar fatty acid compositions, including equal, and low, proportions of DHA, but the vesicles had much more cholesterol and displayed higher anisotropy than the plasma membrane. When cells were grown in DHA-enriched medium, both the plasma membrane and exfoliated vesicles had 10-fold elevated levels of DHA in their phospholipids, with the DHA displacing other polyunsaturates. These cells released vesicles having significantly reduced levels of cholesterol and monoenoic fatty acids than those in normal culture. The anisotropy of these vesicles was also dramatically reduced. These data are consistent with DHA altering the structure and composition of membrane microdomains on the cell surface, and suggest that exfoliated vesicles may prove useful in the further study of membrane microdomains.

Docosahexaenoic acid (DHA) alters the phospholipid molecular species composition of membranous vesicles exfoliated from the surface of a murine leukemia cell line.

Previously, we presented evidence that the vesicles routinely exfoliated from the surface of T27A tumor cells arise from vesicle-forming regions of the plasma membrane and possess a set of lateral microdomains distinct from those of the plasma membrane as a whole. We also showed that docosahexaenoic acid (DHA, or 22:6n-3), a fatty acyl chain known to alter microdomain structure in model membranes, also alters the structure and composition of exfoliated vesicles, implying a DHA-induced change in microdomain structure on the cell surface. In this report we show that enrichment of the cells with DHA reverses some of the characteristic differences in composition between the parent plasma membrane and shed microdomain vesicles, but does not alter their phospholipid class composition. In untreated cells, DHA-containing species were found to be a much greater proportion of the total phosphatidylethanolamine (PE) pool than the total phosphatidylcholine (PC) pool in both the plasma membrane and the shed vesicles. After DHA treatment, the proportion of DHA-containing species in the PE and PC pools of the plasma membrane were elevated, and unlike in untreated cells, their proportions were equal in the two pools. In the vesicles shed from DHA-loaded cells, the proportion of DHA-containing species of PE was the same as in the plasma membrane. However, the proportion of DHA-containing species of PC in the vesicles (0.089) was much lower than that found in the plasma membrane (0.194), and was relatively devoid of species with 16-carbon acyl components. These data suggested that DHA-containing species of PC, particularly those having a 16-carbon chain in the sn-1 position, were preferentially retained in the plasma membrane. The data can be interpreted as indicating that DHA induces a restructuring of lateral microdomains on the surface of living cells similar to that predicted by its behavior in model membranes.

Seroepidemiology of human immunodeficiency virus infection in Borno State of Nigeria by sentinel surveillance.

A serosurvey for human immunodeficiency virus (HIV) infection was carried out in three well-separated population centers in Borno State of Nigeria in 1989-1990. The study subjects were 1,259 made up of sexually transmitted disease (STD) clinic attenders, pregnant women, female prostitutes, and blood donors. Sera were screened by enzyme-linked immunosorbent assay and confirmation was done by Western blotting. The overall seroprevalence was 1.67% (21/1,259), with no significant differences from one population center to another. There were, however, significant differences among the population groups studied: prostitutes, 4.24%; STD clinic attenders, 1.67%; blood donors, 0.71%; and pregnant women, 0.24%. Of the 21 seropositives, 18 were positive for HIV-1 only; 1 was positive for HIV-2 only; and 2 were positive for both HIV-1 and HIV-2. All three HIV-2-positive sera were from prostitutes. Prevalence rates found in this study showed marked increases from 2 to 3 years earlier. There is therefore the need for a vigorous and sustained intervention program.

Solution conformations of barbituric acid derivatives: a 3J(13C,1H) NMR study.

The conformations of the 5-alkyl chains of 5,5-dialkylbarbituric acid derivatives in polar and nonpolar media were determined from the magnitudes of the vicinal heteronuclear coupling constants between the alpha-alkyl hydrogens and the carbonyl carbons. The experimental 3J values have been compared to theoretical values, and the conformational populations of the alkyl side chains with respect to the trioxopyrimidine ring have been determined. The results show that all these compounds have a very low barrier to rotation for both butyl and ethyl side chains. The barbiturates that do not have a 1'-methyl group in the butyl side chain, butobarbital and amobarbital, have no preferred conformation for either the butyl or ethyl side chains. However, the compounds with a 1'-methyl group, pentobarbital and alpha-methylamobarbital, exhibit preferred conformation for both alkyl chains. The significance of these results to the relationship between conformations and pharmacological activity is discussed.

Thermal adaptation in biological membranes: functional significance of changes in phospholipid molecular species composition.

Quantities of 1-palmitoyl 2-docosahexaenoyl phosphatidylcholine (16:0/22:6-PC or PDPC) increase from 24 to 40 weight percent as a consequence of cold acclimation in mitochondrial membranes of rainbow trout liver (J. Comp. Physiol. 156, 665-674, 1986). The present study was undertaken to assess the impact of such a large change in the proportions of a single molecular species on the fluidity, lateral packing (as sensed by phospholipase A2), and permeability of biological membranes. These properties were examined in multilamellar liposomes prepared from binary mixtures of dipalmitoyl phosphatidylcholine (DPPC) and PDPC in proportions increasing from 10 to 40 mole% PDPC. Glucose permeability was positively correlated with both assay temperature and PDPC content. The temperature dependence of Na+ permeability declined steadily as the mole fraction of PDPC increased; consequently, sodium permeability was positively correlated with PDPC content at 5 degrees C, but inversely correlated at 20 degrees C. Phospholipase A2 activity was independent of both assay temperature and vesicle composition. Vesicles of all compositions displayed a single transition in the temperature dependence of 1,6 diphenyl-1,3,5-hexatriene (DPH) fluorescence polarization, which shifted to lower temperature and broadened as proportions of PDPC increased. At temperatures below the transition, fluidity was positively correlated with the mole fraction of PDPC, but interfacial and deeper regions of the bilayer were affected differently by variations in PDPC content. Nonelectrolyte permeability was the only index of membrane structure or function to be significantly correlated with the fluidity of the bilayer interior. The tendencies of PDPC to both fluidize the membrane and to reduce the temperature sensitivity of electrolyte permeation may promote the adaptation of membrane function to low temperature.

Psychological consequences of burn injury.

The major psychological sequelae experienced by patients 1 year after burn injury were investigated. Data were collected on a consecutive series of adult burn patients, (n = 55), including major demographic and epidemiological characteristics. Participants (n = 23) completed the Hospital Anxiety Depression Scale (HADS), the Impact of Event Scale (IES) and a questionnaire covering functional impairment, visibility of the burn, experience of pain, etc. Over one-third of the patients (36.4 per cent) were found to have premorbid characteristics which could predispose them to injury. Over one-third (34.7 per cent) were still experiencing significant psychological problems. Anxiety was most common, followed by posttraumatic stress symptoms and depression. The visibility of the burn was found to be a useful factor in the prediction of psychological outcome (P = 0.001-0.018). No additional variables were found to increase the significance of prediction. Patients indicated that practical advice in the form of staff-led discussions, before or immediately after discharge, would be the most valuable help.

Clear cell sarcoma of soft parts. A case report and review of the literature.

The case of a 25-year-old woman with recurring and metastasizing clear cell sarcoma of soft parts (CCS) is presented. The clinical setting and pathological appearance were in agreement with the original cases described. This report serves to highlight the clinico-pathological features of this rare and aggressive malignancy with specific reference to prognostic markers and treatment.