Trematode parasites as indicators of an animal component in the diet of the Water Vole Arvicola amphibius

The intestinal trematode fauna of the Water Vole Arvicola amphibius, (previously A. terrestris), was investigated to determine whether it might provide evidence of an animal component in the diet of this aquatic herbivorous small mammal. Interrogation of the electronic Host-Parasite Database of the Natural History Museum London revealed the presence of fourteen species of intestinal trematode in water voles, infection with each of which would require the ingestion of tissue from an animal intermediate host. The results obtained using these parasite indicators provide convincing evidence of animal components in the diet of A. amphibius and support anecdotal reports of water voles feeding on animal material in the field.

South Georgia blue whales five decades after the end of whaling

Blue whales Balaenoptera musculus at South Georgia were heavily exploited during 20th century industrial whaling, to the point of local near-extirpation. Although legal whaling for blue whales ceased in the 1960s, and there were indications of blue whale recovery across the wider Southern Ocean area, blue whales were seldom seen in South Georgia waters in subsequent years. We collated 30 yr of data comprising opportunistic sightings, systematic visual and acoustic surveys and photo-identification to assess the current distribution of blue whales in the waters surrounding South Georgia. Over 34000 km of systematic survey data between 1998 and 2018 resulted in only a single blue whale sighting, although opportunistic sightings were reported over that time period. However, since 2018 there have been increases in both sightings of blue whales and detections of their vocalisations. A survey in 2020 comprising visual line transect surveys and directional frequency analysis and recording (DIFAR) sonobuoy deployments resulted in 58 blue whale sightings from 2430 km of visual effort, including the photo-identification of 23 individual blue whales. Blue whale vocalisations were detected on all 31 sonobuoys deployed (114 h). In total, 41 blue whales were photo-identified from South Georgia between 2011 and 2020, none of which matched the 517 whales in the current Antarctic catalogue. These recent data suggest that blue whales have started to return to South Georgia waters, but continued visual and acoustic surveys are required to monitor any future changes in their distribution and abundance.

Chyle leak following an axillary sentinel lymph node biopsy for breast cancer in a patient with superior vena caval thrombosis - a case report and review of the literature

Chyle leak is a very rare complication following an axillary lymph node dissection. We report a case of chyle leak following sentinel lymph node biopsy in a patient with breast cancer with superior vena caval thrombosis. To our knowledge, this is the first case report of chyle leakage following axillary sentinel lymph node biopsy. We describe the aetiology, prevention and treatment strategy that can be adopted in these patients.

Causes of Sudden Death in Epilepsy, and Some Points in the Treatment of Epilepsy

The two subjects that I wish to bring to your notice to-day are sudden death during an epileptic fit, and the present treatment of confirmed epilepsy.

Trophodynamics of Protomyctophum (Myctophidae) in the Scotia Sea (Southern Ocean)

This study investigated spatial and temporal patterns in distribution, population structure and diet of Bolin's lanternfish Protomyctophum bolini, Tenison's lanternfish Protomyctophum tenisoni and gaptooth lanternfish Protomyctophum choriodon in the Scotia Sea using data collected by midwater trawl during spring, summer and autumn. Protomyctophum bolini was the most abundant species of the genus encountered throughout the Scotia Sea with the greatest concentrations occurring around the Antarctic Polar Front (APF). This species had a life cycle of 2+ years, but spatial differences in population structure were apparent as the I-group was absent from all regions south of the APF, suggesting that the species does not recruit in the Scotia Sea. Protomyctophum tenisoni occurred mostly in waters characteristic of the APF and was absent from the southern Scotia Sea. It had a limited size range, but there was clear size-related sexual dimorphism with males significantly larger than females. The species had a life cycle of c. 2 years, but the I-group (c. 1 year old, 1 November to 31 October the next year) occurred only in regions close to the APF suggesting that recruitment is restricted to these waters. A seasonal southward migration for P. choriodon is likely as the species occurred mostly to the south-west of South Georgia in summer, but extended to the sea-ice sectors in autumn. Protomyctophum choriodon had a life cycle of 4+ years in the Scotia Sea and the population was dominated by age classes >3 years old. Larval stages were absent during the surveys for all species. Diurnal variations in vertical distribution were apparent for all three species. Interspecific variations in diet were evident, but all species were primarily copepod feeders, with Metridia spp., Rhincalanus gigas and Calanus simillimus generally dominating their diet. Small euphausiids, principally Thysanoessa spp., were also an important component of their diets, particularly for P. choriodon which had the largest body size. The spatial and temporal variations in diet for both P. bolini and P. tenisoni were broadly consistent with underlying abundance patterns within the mesozooplankton community.

Does diisocyanate exposure result in neurotoxicity?

CONTEXT

Diisocyanates have been associated with respiratory and dermal sensitization. Limited number of case reports, and a few case studies, media, and other references suggest potential neurotoxic effects from exposures to toluene diisocyanate (TDI), 1,6 hexamethylene diisocyanate (HDI), and methylene diisocyanate (MDI). However, a systematic review of the literature evaluating the causal association on humans does not exist to support this alleged association.

OBJECTIVE

To perform systematic review examining the body of epidemiologic evidence and provide assessment of causal association based on principles of the Sir Austin Bradford Hill criteria or considerations for causal analysis.

METHODS

A comprehensive search of public databases for published abstracts, case reports, cross-sectional surveys, and cohort studies using key search terms was conducted. Additional searches included regulatory reviews, EU IUCLID and EU Risk Assessment databases, and unpublished reports in the International Isocyanate Institute database. An expert panel consisting of physicians, toxicologists, and an epidemiologist critically reviewed accepted papers, providing examination of epidemiologic evidence of each report. Finally, the Hill criteria for causation were applied to the summative analysis of identified reports to estimate probability of causal association.

RESULTS

Twelve papers reporting exposed populations with a variety of neurological symptoms or findings suitable for analysis were identified, including eleven case or case series reports, and one cross-sectional study. Three papers reported on the same population. Each of the papers was limited by paucity of diisocyanate exposure estimates, the presence of confounding exposures to known or suspected neurotoxicants, a lack of objective biological measures of exposure or neurotoxic effects, and lack of relative strength of association measures. Additionally, reported health symptoms and syndromes lacked consistency or specificity. No plausible mechanism of toxicity was found. Application of a predictive mathematical model for determining probability of causal association for neurotoxicity was calculated to be 21%.

CONCLUSION

There is insufficient evidence for a causal association of neurotoxic effects and diisocyanate exposure based on lack of evidence in all categories of the Hill criteria for causality except for temporal association of reported symptoms and alleged exposure. Future reports should attempt to address more rigorous exposure assessment and control for confounding exposures.

Long-term changes in deep-water fish populations in the northeast Atlantic: a deeper reaching effect of fisheries?

A severe scarcity of life history and population data for deep-water fishes is a major impediment to successful fisheries management. Long-term data for non-target species and those living deeper than the fishing grounds are particularly rare. We analysed a unique dataset of scientific trawls made from 1977 to 1989 and from 1997 to 2002, at depths from 800 to 4800 m. Over this time, overall fish abundance fell significantly at all depths from 800 to 2500 m, considerably deeper than the maximum depth of commercial fishing (approx. 1600 m). Changes in abundance were significantly larger in species whose ranges fell at least partly within fished depths and did not appear to be consistent with any natural factors such as changes in fluxes from the surface or the abundance of potential prey. If the observed decreases in abundance are due to fishing, then its effects now extend into the lower bathyal zone, resulting in declines in areas that have been previously thought to be unaffected. A possible mechanism is impacts on the shallow parts of the ranges of fish species, resulting in declines in abundance in the lower parts of their ranges. This unexpected phenomenon has important consequences for fisheries and marine reserve management, as this would indicate that the impacts of fisheries can be transmitted into deep offshore areas that are neither routinely monitored nor considered as part of the managed fishery areas.

Effects of different feed additives alone or in combination on broiler performance, gut microflora and ileal histology

1. The objectives of this experiment were to investigate the effects of different xylanases, alone or in combination with different organic acid and oligosaccharide sources, on bird performance, gut microflora and ileal histology. 2. Birds were given a diet based on a commercial formulation, which was split into 8 batches. Batch 1 contained the antibiotic growth promoter Avilamycin and acted as the positive control. To batch 2 the enzyme Allzyme PT was added and to batch 3 Allzyme PT was added with the organic acid and oligosaccharide mixture Avimos. To batch 4, Allzyme PT was added with the oligosaccharide mixture Biomos. To batch 5, yeast extract 2012 was added with the organic acid mixture Gustor and the enzyme xylanase XP20. To batch 6, yeast extract 2012 and feed acidifier Gustor were added as before, with the enzyme Avizyme 1300. Batches 7 and 8 both acted as negative experimental controls, with no added growth promoters. 3. A total of 64 birds were housed in individual wire cages in each of three consecutive experimental replicates (24 birds/treatment). Birds were fed ad libitum from 7 to 28 d and a 7-d excreta collection was carried out to determine apparent metabolisable energy (AME) content. 4. At 28 d, the birds were killed and viscosity of jejunal digesta supernatant and gizzard weight were determined. Samples were taken from the crop, ileum and caecum and analysed for viable presumptive lactic acid bacteria and coliforms. The overall microbial flora was determined using denaturing gradient gel electrophoresis of 16S ribosomal DNA followed by DNA sequence analysis in order to assign amplicons to a bacterial species. Ileal sections were also collected for histological analysis. 5. Total live weight gain (12%) and gain:feed (9%) were significantly improved for all diets containing additives, compared to the negative control diets. All diets containing xylanases gave significantly lower in vivo viscosity values than the positive and negative controls. Diet treatment significantly affected viable coliform numbers in the ileum and also viable lactobacilli in the ileum and caecum. A substantial proportion of the bacteria present in the GI tract (40%) belong to unknown species. No effects of diet treatment on histological measurements were observed in this study. 6. All the additive combinations studied were at least as effective as the antibiotic growth promoter and the results for Allzyme PT suggest that xylanase alone is as effective as any of the combinations studied.

Metastatic colorectal cancer (mCRC) patterns of care: Implications for clinical trial design

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Background: New approaches have expanded options for patients (pts) with mCRC. To characterize current practice paradigms that might bear on clinical trial design, we analyzed decision-making and treatment patterns in pts treated at a Comprehensive Cancer Center since the introduction of cetuximab (CET), and bevacizumab (BV). Methods: A retrospective review of all pts diagnosed with mCRC between 3/1/04 and 8/28/06 treated at Fox Chase Cancer Center. Results: 160 pts were treated, with 157 pts receiving at least one therapy regimen by 10 attending oncologists. There were 350 changes in therapy with 246 (70%) including continuation of at least one prior drug (92 BV, 111 fluoropyrimidines, 43 other). The most common reasons for treatment change were toxicity (33%), progressive disease (PD) (29%), treatment breaks (15%), and metastasectomy (11%) ( Table ). PD was a more common cause for treatment discontinuation in later phases of treatment (18% initial regimen vs. 36% subsequent regimens, p=0.0002). 24% of pts treated with oxaliplatin (OX) discontinued due to neuropathy. Hypersensitivity caused discontinuation in 5% of pts with OX and 7% of pts with CET. Resection of metastases was undertaken in 38% of pts. 43% of these pts received neoadjuvant therapy, and 56% received adjuvant therapy. 30% of pts have died, 29% remain on active treatment, 28% are on a treatment break, 3% are on hospice, and 11% are lost to follow-up. Conclusions: PD is no longer the primary reason for change of therapy in pts with mCRC. Metastasectomy is common and OX neuropathy is often treatment-limiting. These findings have important implications for endpoint selection and design of clinical trials in mCRC. Future clinical trials in mCRC must recognize treatment complexities and capture key components of decision-making that may result in prolonged survival. Furthermore, treatment breaks represent a potential window for the evaluation of new drugs.

[Table: see text]

No significant financial relationships to disclose.

Spatial and temporal operation of the Scotia Sea ecosystem: a review of large-scale links in a krill centred food web

The Scotia Sea ecosystem is a major component of the circumpolar Southern Ocean system, where productivity and predator demand for prey are high. The eastward-flowing Antarctic Circumpolar Current (ACC) and waters from the Weddell-Scotia Confluence dominate the physics of the Scotia Sea, leading to a strong advective flow, intense eddy activity and mixing. There is also strong seasonality, manifest by the changing irradiance and sea ice cover, which leads to shorter summers in the south. Summer phytoplankton blooms, which at times can cover an area of more than 0.5 million km2, probably result from the mixing of micronutrients into surface waters through the flow of the ACC over the Scotia Arc. This production is consumed by a range of species including Antarctic krill, which are the major prey item of large seabird and marine mammal populations. The flow of the ACC is steered north by the Scotia Arc, pushing polar water to lower latitudes, carrying with it krill during spring and summer, which subsidize food webs around South Georgia and the northern Scotia Arc. There is also marked interannual variability in winter sea ice distribution and sea surface temperatures that is linked to southern hemisphere-scale climate processes such as the El Niño-Southern Oscillation. This variation affects regional primary and secondary production and influences biogeochemical cycles. It also affects krill population dynamics and dispersal, which in turn impacts higher trophic level predator foraging, breeding performance and population dynamics. The ecosystem has also been highly perturbed as a result of harvesting over the last two centuries and significant ecological changes have also occurred in response to rapid regional warming during the second half of the twentieth century. This combination of historical perturbation and rapid regional change highlights that the Scotia Sea ecosystem is likely to show significant change over the next two to three decades, which may result in major ecological shifts.

Tamoxifen effect on L-DOPA induced response complications in parkinsonian rats and primates

The contribution of striatal protein kinase C (PKC) isoform changes in levodopa (L-DOPA) induced motor response complications in parkinsonian rats was investigated and the ability of tamoxifen, an antiestrogen with a partial PKC antagonist property, to prevent these response alterations in 6-hydroxydopamine (6-OHDA) lesioned rats as well as in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treated cynomologous monkeys was studied. Following treatment of adult male rats with L-DOPA twice daily for 3 weeks, protein levels of left (lesioned) and right (intact) striatal PKC isoforms were measured. Western blot analysis showed increased protein expression of both the novel PKC epsilon isoform and the atypical PKC lambda isoform ipsilateral to the lesion (174+/-17% for epsilon, 140+/-9% for lambda, of intact striatum in 6-OHDA lesioned plus chronic L-DOPA treated animals) in acute L-DOPA treated rats. No enhancement was observed in PKC immunoreactivity for other isoforms. Tamoxifen (5.0 mg/kg p.o.) significantly attenuated the L-DOPA induced augmentation of protein expression of PKC epsilon and PKC lambda, but had no effect on immunoreactivity for other PKC isoforms. In chronic L-DOPA treated parkinsonian rats, tamoxifen prevented (5.0 mg/kg p.o.) as well as ameliorated (5.0 mg/kg p.o.) the characteristic shortening in duration of motor response to L-DOPA challenge. In MPTP lesioned primates, similar to the ameliorative effect seen in rats, tamoxifen (1 and 3 mg/kg p.o) reduced the appearance of L-DOPA induced dyskinesia by 61% and 55% respectively (p<0.05). These results suggest that changes in specific striatal PKC isoforms contribute to the pathogenesis of L-DOPA induced motor complications and further that drugs able to selectively inhibit these signaling kinases might provide adjunctive benefit in the treatment of Parkinson's disease.

Trends in body size across an environmental gradient: a differential response in scavenging and non-scavenging demersal deep-sea fish

Body size trends across environmental gradients are widely reported but poorly understood. Here, we investigate contrasting relationships between size (body mass) and depth in the scavenging and predatory demersal ichthyofauna (800-4800 m) of the North-east Atlantic. The mean size of scavenging fish, identified as those regularly attracted to baited cameras, increased significantly with depth, while in non-scavengers there was a significant decline in size. The increase in scavenger size is a consequence of both intra and inter-specific effects. The observation of opposing relationships, in different functional groups, across the same environmental gradient indicates ecological rather than physiological causes. Simple energetic models indicate that the dissimilarity can be explained by different patterns of food distribution. While food availability declines with depth for both groups, the food is likely to be in large, randomly distributed packages for scavengers and as smaller but more evenly distributed items for predators. Larger size in scavengers permits higher swimming speeds, greater endurance as a consequence of larger energy reserves and lower mass specific metabolic rate, factors that are critical to survival on sporadic food items.

Combined blockade of AMPA and NMDA glutamate receptors reduces levodopa-induced motor complications in animal models of PD

AMPA and NMDA receptors, abundantly expressed on striatal medium spiny neurons, have been implicated in the regulation of corticostriatal synaptic efficacy. To evaluate the contribution of both glutamate receptor types to the pathogenesis of motor response alterations associated with dopaminergic treatment, we studied the ability of the selective AMPA receptor antagonist GYKI-47261 and the selective NMDA receptor antagonists, MK-801 and amantadine, to mitigate these syndromes in rodent and primate models of Parkinson's disease. The effects of GYKI-47261 and amantadine (or MK-801), alone and in combination, were compared for their ability to modify dyskinesias induced by levodopa. In rats, simultaneous administration of subthreshold doses of AMPA and NMDA receptor antagonists completely normalized the wearing-off response to acute levodopa challenge produced by chronic levodopa treatment (P < 0.05). In primates, the glutamate antagonists GYKI-47261 and amantadine, co-administered at low doses (failing to alter dyskinesia scores), reduced levodopa-induced dyskinesias by 51% (P < 0.05). The simultaneous AMPA and NMDA receptor blockade acts to provide a substantially greater reduction in the response alterations induced by levodopa than inhibition of either of these receptors alone. The results suggest that mechanisms mediated by both ionotropic glutamate receptors make an independent contribution to the pathogenesis of these motor response changes and further that a combination of both drug types may provide relief from these disabling complications at lower and thus safer and more tolerable doses than required when either drug is used alone.

Accurate social perception at zero acquaintance: the affordances of a Gibsonian approach

We review research on accurate social perception at zero acquaintance and apply a Gibsonian ecological approach to redress several shortcomings. We argue that recent use of Brunswik's lens model to determine what physical qualities accurately communicate psychological traits has limited utility because it fails to consider the structured information provided by configural physical qualities that is central to Gibson's (1979) theory. We elaborate a developmental model of relationships between physical and psychological qualities that highlights research needed to identify configural physical qualities that may inform accurate perceptions. This model and tenets of the ecological theory yield several hypotheses regarding such qualities. Finally, we advocate the value of studying perceived affordances (opportunities for acting, interacting, or being acted upon) because this will focus attention on the neglected issue of contextual influences on social perception accuracy, and because affordances may be perceived more accurately than global personality traits.

Application of the modified Shepard interpolation method to the determination of the potential energy surface for a molecule–surface reaction: H2+Pt(111)

We have used a modified Shepard (MS) interpolation method, initially developed for gas phase reactions, to build a potential energy surface (PES) for studying the dissociative chemisorption of H2 on Pt(111). The aim was to study the efficiency and the accuracy of this interpolation method for an activated multidimensional molecule-surface reactive problem. The strategy used is based on previous applications of the MS method to gas phase reactions, but modified to take into account special features of molecule-surface reactions, like the presence of many similar reaction pathways which vary only slightly with surface site. The efficiency of the interpolation method was tested by using an already existing PES to provide the input data required for the construction of the new PES. The construction of the new PES required half as many ab initio data points as the construction of the old PES, and the comparison of the two PESs shows that the method is able to reproduce with good accuracy the most important features of the H2 + Pt(111) interaction potential. Finally, accuracy tests were done by comparing the results of dynamics simulations using the two different PESs. The good agreement obtained for reaction probabilities and probabilities for rotationally and diffractionally inelastic scattering shows clearly that the MS interpolation method can be used efficiently to yield accurate PESs for activated molecule-surface reactions.

Completed sequence of plasmid pIP501 and origin of spontaneous deletion derivatives

The sequence of plasmid pIP501 (30,603 bp) was completed using previously published and newly acquired data. The sites at which two spontaneous deletions had occurred were identified. One was between tracts of repeated heptamers and the other between regions of secondary structure associated with plasmid replication. A high level of identity ( >95%) between plasmid pIP501 and part of plasmid pRE25, which had been isolated from Enterococcus faecalis associated with a food source, was confirmed.

Cross section for the H+H2O abstraction reaction: experiment and theory

The absolute value of the cross section for the abstraction reaction between fast H atoms and H2O has been determined experimentally at a mean collision energy of 2.46 eV. The OH population distribution at the same mean energy has also been determined. The new measurements are compared with state-of-the-art quantum mechanical and quasiclassical scattering calculations on the most recently developed potential energy surface.

Human immunodeficiency virus type 1 gp120 and ethanol coexposure in rat organotypic brain slice cultures: Curtailment of gp120-induced neurotoxicity and neurotoxic mediators by moderate but not high ethanol concentrations

Human immunodeficiency virus type 1 (HIV-1) envelope protein gp120, implicated with other retroviral proteins in acquired immunodeficiency syndrome (AIDS)-related dementia, causes neuronal degeneration by inciting cascades of neurotoxic mediators from glia. It also may facilitate neuronal glutamate (N-methyl-D-aspartate, NMDA) receptor-mediated excitotoxicity by interacting at the glycine coagonist site. The authors reported that preconditioning rat organotypic hippocampal-cortical slice cultures subchronically with ethanol at concentrations occurring during moderate drinking (20 to 30 mM) prevented gp120's induction of neurotoxic mediators and intracellular calcium, as well as neuronal death. The authors now find that the acute copresence of ethanol in moderate as opposed to high concentrations similarly blocks the retroviral protein's neurotoxic effects in brain slice cultures, assessed with lactate dehydrogenase (LDH) release and propidium iodide (PI) labeling. As with ethanol preconditioning, neuroprotection against gp120 by moderate ethanol coexposure appears secondary to abrogation of the retroviral protein's early induction of arachidonic acid (AA), glutamate, and superoxide (but not nitric oxide) elevations/release. Additionally, experiments indicate that 30 mM ethanol is sufficient to inhibit the NMDA receptor, particularly in the presence of added glycine, thus hindering potential direct neuronal stimulation by gp120. However, in contrast to moderate ethanol, 100 mM ethanol, a concentration tolerated only in chronic alcoholics, potentiates gp120-dependent neurotoxicity (PI labeling) in the hippocampal CA1 region, augments LDH release, and fails to curtail gp120's actions on AA, glutamate, and superoxide-but does suppress nitric oxide induction. The results indicate dominant roles for AA, superoxide, and glutamate-mediated oxidative stress in gp120's neurotoxic mechanism, but perhaps a less important role for NMDA receptor stimulation, which would be constrained at both ethanol concentrations employed. We suggest that ethanol's concentration-dependent, two-edged sword behavior could alter the development of dementia in HIV-1-infected individuals during social consumption or abuse. Further studies are needed to elucidate the differing apparently glial effects of the two concentrations of ethanol.

DNA cloning in Lactobacillus helveticus by the exconjugation of recombinant mob-containing plasmid constructs from strains of transformable lactic acid bacteria

A system developed for the genetic transfer of plasmids between strains of nontransformable bacteria (P. Langella, Y. le Loir, S. D. Ehrlich and A. Gruss, 1993, J. Bacteriol., 175, 5806-5813) by the specific inclusion of a mobilization (mob) region into a nonconjugative shuttle vector was used successfully to deliver the genetic determinants for beta-glucanase, beta-glucuronidase, and green fluorescent protein to Lactobacillus helveticus. Expression of two of the genes could be detected in the new host. Data suggested that resolution of cointegrates into components could release the original recombinant plasmid or generate a cointegrate deletion. All the recombinant plasmids were segregationally unstable in Lb. helveticus and there was some evidence for structural instability. Intrinsic instability in the mob-containing vector was reduced by replacing the duplicated pBluescript polylinker with that from pUC19. Sites at which cointegrate formation could occur were localized at two distinct tracts close to the D-loop that forms at the primosome during plasmid replication.

Effect of race and resistance training status on the density of fat-free mass and percent fat estimates

The impact of race and resistance training status on the assumed density of the fat-free mass (D(FFM)) and estimates of body fatness via hydrodensitometry (%Fat(D)) vs. a four-component model (density, water, mineral; %Fat(D,W,M)) were determined in 45 men: white controls (W; n = 15), black controls (B; n = 15), and resistance-trained blacks (B-RT; n = 15). Body density by hydrostatic weighing, body water by deuterium dilution, and bone mineral by dual-energy X-ray absorptiometry were used to estimate %Fat(D,W,M). D(FFM) was not different between B and W (or 1.1 g/ml); however, D(FFM) in B-RT was significantly lower (1.091 +/- 0.012 g/ml; P < 0.05). Therefore, %Fat(D) using the Siri equation was not different from %Fat(D,W,M) in W (17.5 +/- 5.0 vs. 18.3 +/- 5.4%) or B (14.9 +/- 5.6 vs. 15.7 +/- 5.7%) but significantly overestimated %Fat(D,W,M) in B-RT (14.0 +/- 5.9 vs. 10.4 +/- 6.0%; P < 0.05). The use of a race-specific equation (assuming D(FFM) = 1.113 g/ml) did not improve the agreement between %Fat(D) and %Fat(D,W,M), resulting in a significantly greater mean (+/-SD) discrepancy for B (1.7 +/- 1.8% fat) and B-RT (6.2 +/- 4.3% fat). Thus race per se does not affect D(FFM) or estimates of %Fat(D); however, B-RT have a D(FFM) lower than 1.1 g/ml, leading to an overestimation of %Fat(D).

Ethanol pre-exposure suppresses HIV-1 glycoprotein 120-induced neuronal degeneration by abrogating endogenous glutamate/Ca2+-mediated neurotoxicity

The neurotoxic mechanism of HIV-1 envelope glycoprotein 120 (gp120) involves glutamatergic (NMDA) receptor/Ca2+-dependent excitotoxicity, mediated in part via glia. Pro-inflammatory cytokines also may have roles. We have reported that pre-exposure of brain cultures to 'physiological' ethanol concentrations (20-30 mM) protects against neuronal damage from HIV-1 gp120, but not from the direct receptor agonist, NMDA. Using lactate dehydrogenase assays and propidium iodide staining of rat organotypic hippocampal-entorhinal cortical slice cultures we determined that ethanol's suppression of gp120 neurotoxicity required at least 4 days of pretreatment. The gp120-induced neurotoxicity was accompanied by interleukin-6 elevations that were not affected by the pretreatment. However, gp120 induced substantial, early increases in extracellular glutamate levels that were blocked by ethanol pretreatment, conceivably abrogating excitotoxicity. Consistent with abrogation of excitotoxic pathways, fura-2 imaging showed selective deficits in gp120-dependent intracellular Ca2+ responses in ethanol-pretreated slices. Gp120 is believed to increase glutamate levels by both stimulating release and inhibiting (re)uptake. Results with a labeled glutamate analog, D-[3H]aspartate, revealed that gp120's inhibition of glutamate uptake, rather than its stimulation of release, was abolished after ethanol. Further studies indicated that two converging effects of ethanol pretreatment may underlie the abolishment of gp120-mediated glutamate uptake inhibition: (a) blockade of gp120-induced release (ostensibly from glia) of arachidonic acid, an inhibitor of astroglial glutamate reuptake, and (b) modest proliferation and activation of astroglia upon gp120 stimulation--which are likely to augment glutamate transporters. Thus, as with gp120 itself, glia and glutamate/arachidonic acid regulation appear to be important targets for ethanol. Since moderate ethanol consumption is as common among HIV-infected individuals as in the general population, this newly recognized neuroprotective (and apparently anti-excitotoxic) effect of ethanol withdrawal in vitro could be important, but it requires further study before its significance, if any, is understood.

The effects of benzodiazepines on human opioid receptor binding and function

We performed in vitro studies to investigate the potential interaction of benzodiazepines with cloned human opioid receptor subtypes. Midazolam, chlordiazepoxide, and diazepam directly displaced [(3)H]-diprenorphine binding from kappa and delta receptors, but not mu receptors, whereas flumazenil was inactive. These benzodiazepines also stimulated (35)S-GTPgammaS binding in membranes containing human kappa receptors, and the effect of midazolam was prevented by a selective kappa antagonist. Midazolam was also weakly active at delta-receptor activation, whereas all three were inactive at mu receptors. The results suggest that the analgesic efficacy reported for intrathecal benzodiazepines may be attributed, in part, to direct interaction with kappa-opioid receptors.

IMPLICATIONS

Several human and animal studies have shown analgesic effects of benzodiazepines after spinal injection. Our results show that large concentrations of midazolam, chlordiazepoxide, and diazepam displace the binding of [(3)H]-diprenorphine-an opiate radioligand from kappa receptors. In an in vitro functional assay, midazolam is a weak agonist at the delta-opioid receptor, whereas all three benzodiazepines are kappa-opioid agonists. These findings may partially explain the mechanism of benzodiazepine-induced spinal analgesia.

Use of air displacement plethysmography for estimating body fat in a four-component model

PURPOSE

To compare measurements of body density (D(b)) obtained from air displacement plethysmography (AP) and hydrostatic weighing (HW) and to determine the accuracy of substituting D(b) via AP (D(b)-AP) for D(b) via HW (D(b)-HW) in estimating body fatness (%Fat(4C)) and the composition and density of the fat-free mass (Dffm) from a four-component model (fat, mineral, water, and protein).

METHODS

D(b) was measured in 50 young adults using AP and HW. Total body water via deuterium dilution, bone mineral content via dual-energy x-ray absorptiometry, and D(b) were used to estimate %Fat(4C).

RESULTS

D(b)-AP and D(b)-HW were highly correlated (r = 0.89, SEE = 0.008 g x mL(-1)), but D(b)-AP (1.065 +/- 0.003 g x mL(-1)) was significantly higher (P < 0.05) than D(b)-HW (1.058 +/- 0.003 g x mL(-1)), resulting in a mean difference of 2.8%fat. Differences between %Fat(4C-AP) (17.8 +/- 1.2%) and %Fat(4C-HW) (19.3 +/- 1.2%) were significant (P < 0.05), but the SD of the differences (2.3%) was low. When D(b)-AP was used in a four-component model in place of D(b)-HW, the calculated Dffm was significantly higher (1.109 +/- 0.002 vs 1.105 +/- 0.002 g x mL(-1)) based on a higher (P < 0.05) protein fraction (22.0 +/- 0.4% vs 20.6 +/- 0.4%) and lower (P < 0.05) water (71.1 +/- 0.4% vs 72.4 +/- 0.4%) and mineral fractions (7.0 +/- 0.1% vs 7.1 +/- 0.1%).

CONCLUSIONS

AP yields a higher D(b) than HW and may not be a valid method for measuring D(b) or estimating %fat using densitometry. However, due to relatively small bias and low individual error, D(b)-AP is an acceptable substitute for D(b)-HW when estimating %fat with a four-component model in young adults.

First-principles theory for the H + H2O, D2O reactions

A full quantum dynamical study of the reactions of a hydrogen atom with water, on an accurate ab initio potential energy surface, is reported. The theoretical results are compared with available experimental data for the exchange and abstraction reactions in H + D2O and H + H2O. Clear agreement between theory and experiment is revealed for available thermal rate coefficients and the effects of vibrational excitation of the reactants. The excellent agreement between experiment and theory on integral cross sections for the exchange reaction is unprecedented beyond atom-diatom reactions. However, the experimental cross sections for abstraction are larger than the theoretical values by more than a factor of 10. Further experiments are required to resolve this.

Phosphorylation of serine 43 is not required for inhibition of c-Raf kinase by the cAMP-dependent protein kinase

The activity of the serine/threonine kinase c-Raf (Raf) is inhibited by increased intracellular cAMP. This is believed to require phosphorylation with the cAMP-dependent protein kinase (PKA), although the mechanism by which PKA inhibits Raf is controversial. We investigated the requirement for PKA phosphorylation using Raf mutants expressed in HEK293 or NIH 3T3 cells. Phosphopeptide mapping of (32)P-labeled Raf (WT) or a mutant lacking a putative PKA phosphorylation site (serine to alanine, S43A) confirmed that serine 43 (Ser(43)) was the major cAMP (forskolin)-stimulated phosphorylation site in vivo. Interestingly, the EGF-stimulated Raf kinase activity of the S43A mutant was inhibited by forskolin equivalently to that of the WT Raf. Forskolin also inhibited the activation of an N-terminal deletion mutant Delta5-50 Raf completely lacking this phosphorylation site. Although WT Raf was phosphorylated by PKA, phosphorylation did not inhibit Raf catalytic activity in vitro, nor did forskolin treatment inhibit the activity of an N-terminally truncated Raf protein (Raf 22W) or a full-length Raf protein (Raf-CAAX) expressed in NIH 3T3 cells. In contrast, forskolin inhibited the EGF-dependent activation of a Raf isoform (B-Raf), lacking an analogous phosphorylation site to Ser(43). Thus, these results demonstrate that PKA exerts its inhibitory effects independently of direct Raf phosphorylation and suggests instead that PKA prevents an event required for the EGF-dependent activation of Raf.

Selective methylation changes on the Bacillus subtilis chemotaxis receptor McpB promote adaptation

The Bacillus subtilis McpB is a class III chemotaxis receptor, from which methanol is released in response to all stimuli. McpB has four putative methylation sites based upon the Escherichia coli consensus sequence. To explore the nature of methanol release from a class III receptor, all combinations of putative methylation sites Gln(371), Gln(595), Glu(630), and Glu(637) were substituted with aspartate, a conservative substitution that effectively eliminates methylation. McpB((Q371D,E630D,E637D)) in a Delta(mcpA mcpB tlpA tlpB)101::cat mcpC4::erm background failed to release methanol in response to either the addition or removal of the McpB-mediated attractant asparagine. In the same background, McpB((E630D,E637D)) produced methanol only upon asparagine addition, whereas McpB((Q371D,E630D)) produced methanol only upon asparagine removal. Thus methanol release from McpB was selective. Mutants unable to methylate site 637 but able to methylate site 630 had high prestimulus biases and were incapable of adapting to asparagine addition. Mutants unable to methylate site 630 but able to methylate site 637 had low prestimulus biases and were impaired in adaptation to asparagine removal. We propose that selective methylation of these two sites represents a method of adaptation novel from E. coli and present a model in which a charged residue rests between them. The placement of this charge would allow for opposing electrostatic effects (and hence opposing receptor conformational changes). We propose that CheC, a protein not found in enteric systems, has a role in regulating this selective methylation.

Increased beta-carboline 9N-methyltransferase activity in the frontal cortex in Parkinson's disease

Enzymatic beta-carboline N-methyltransferase activities generate N-methylated beta-carbolinium cations that are analogs of the parkinsonian-producing neurotoxin MPP+. We measured beta-carboline-2N-methyltransferase and beta-carboline-9N-methyltransferase activities in the supernatant and particulate fractions from postmortem human brains. These N-methyltransferase activities were assessed in the substantia nigra, putamen, and frontal cortex from control and Parkinson's disease cases. No significant differences were measured in any brain region in particulate and supernatant fraction beta-carboline 2N-methyltransferase activity or particulate fraction beta-carboline 9N-methyltransferase activity. Likewise, supernatant fraction beta-carboline 9N-methyltransferase activity was similar in the putamen and substantia nigra from Parkinson's disease and control cases. Unexpectedly, supernatant fraction beta-carboline 9N-methyltransferase activity was increased fourfold in Parkinson's disease frontal cortex (P < 0.05), suggesting that beta-carboline N-methylation may play a role in Parkinson's disease.

HIV-I gpI20 neurotoxicity in brain cultures is prevented by moderate ethanol pretreatment

The HIV-1 coat protein gp 20, a potent neurotoxin that may underlie AIDS dementia, activates glia to cause neurotoxicity via the NMDA receptor and perhaps other routes. We find that pretreating cultures of rat organotypic cortical/hippocampal slices or cerebellar granule cells subchronically with ethanol in physiological concentrations (20-30 mM; 6 days) largely or even completely inhibits neurodegeneration due to gp120. However, NMDA-induced neurotoxicity appears unaffected by moderate ethanol pretreatment, indicating that ethanol's neuroprotection against gp120 is upstream of the NMDA receptor, possibly at a glial activation stage. The results could lead to a better understanding of relationships between ethanol, glia and neurodegeneration, particularly in AIDS.

Regulation of carbamoyl phosphate synthetase by MAP kinase

The de novo synthesis of pyrimidine nucleotides is required for mammalian cells to proliferate. The rate-limiting step in this pathway is catalysed by carbamoyl phosphate synthetase (CPS II), part of the multifunctional enzyme CAD. Here we describe the regulation of CAD by the mitogen-activated protein (MAP) kinase cascade. When phosphorylated by MAP kinase in vitro or activated by epidermal growth factor in vivo, CAD lost its feedback inhibition (which is dependent on uridine triphosphate) and became more sensitive to activation (which depends upon phosphoribosyl pyrophosphate). Both these allosteric regulatory changes favour biosynthesis of pyrimidines for growth. They were accompanied by increased epidermal growth factor-dependent phosphorylation of CAD in vivo and were prevented by inhibition of MAP kinase. Mutation of a consensus MAP kinase phosphorylation site abolished the changes in CAD allosteric regulation that were stimulated by growth factors. Finally, consistent with an effect of MAP kinase signalling on CPS II activity, epidermal growth factor increased cellular uridine triphosphate and this increase was reversed by inhibition of MAP kinase. Hence these studies may indicate a direct link between activation of the MAP kinase cascade and de novo biosynthesis of pyrimidine nucleotides.

Impact of bone mineral estimates on percent fat estimates from a four-component model

PURPOSE

The primary purpose of this study was to determine the impact of bone mineral content (BMC) from QDR 1000/W and DPX-L dual-energy x-ray absorptiometers (DXA(QDR) and DXA(DPX-L) on percent fat (%fat) estimates from a four-component model. A secondary purpose was to test the accuracy of %fat estimates from DXA(QDR) and DXA(DPX-L) using %fat estimates from a four-component model as the criterion.

METHODS

Percent fat, fat mass, and fat-free mass (FFM) were determined from DXA(QDR) and DXA(DPX-L) and from a four-component model based on measures of body density from underwater weighing, body water from deuterium dilution, and BMC from DXA(QDR) (4C(QDR)) or DXA(DPX-L) (4C(DPX-L)) in young men (N = 14) and women (N = 10).

RESULTS

BMC was significantly lower using DXA(QDR) compared with DXA(DPX-L) (approximately 11%), resulting in slightly lower estimates of %fat and fat mass and slightly higher estimates of FFM from 4C(QDR) than 4C(DPX-L). Although estimates of %fat, fat mass, and FFM from DXA(QDR) and DXA(DPX-L) were not different than those from a four-component model, there was considerable individual variability between methods. Furthermore, %fat from DXA(QDR) was lower than %fat from 4C(DPX-L).

CONCLUSIONS

We conclude that using BMC from different DXA instruments has a minimal impact on %fat, fat mass, and FFM estimates from a four-component model. The large variability in %fat estimates between the two DXA instruments and those from a four-component model does not support DXA as a criterion method of body composition. Further studies involving larger sample sizes and specific population groups are needed to assess the validity of body composition measurements from DXA.

Driving drug discovery and patient therapy via the encapsulation and fusion of knowledge

Knowledge and Knowledge Management are becoming common senior management parlance in the Pharmaceutical Industry in the late 1990s. This perspective article will address exactly what is knowledge and the various techniques available to harness and use it to drive the pharmaceutical business process. The impact of knowledge on this process to provide a better service to the industry's customers (the patient) are discussed with respect to the key business problems facing the industry as it enters the new millennium.

Complete sequence of plasmid pLH1 from lactobacillus helveticus ATCC15009: analysis reveals the presence of regions homologous to other native plasmids from the host strain

The complete sequence for plasmid pLH1 from Lactobacillus helveticus ATCC15009 has been determined. Analysis of the 19,360-bp primary sequence revealed a putative replication origin and initiation protein, information that could provide the basis for the construction of cloning vectors for L. helveticus. Evidence that pLH1 is theta-replicating could be deduced from the plasmid size, from the homology to the replication protein of the Bacillus natto theta-replicating plasmid pLS32, and from the identification of a putative resolvase gene (orf-195). Although 14 open reading frames capable of encoding polypeptides longer than 100 amino acids were identified, none, on the basis of homology with known sequences, appeared to encode a well-characterized trait relevant to milk fermentation. Plasmid pLH1 revealed regions of identity with the smaller cryptic plasmids (pLH2 and pLH3) from the same strain and with other tracts of DNA, including insertion sequence elements, from a variety of other lactic acid bacteria. The presence of such regions provides a basis for developing an explanation of the phenotypic variability observed in these bacteria. The plasmid also appears to possess a number of genetic elements present in other lactic acid bacterial plasmids, conservation of which would be consistent with an important functional or evolutionary role. It could be argued that the plasmid complement of L. helveticus ATCC15009 consists of parasitic entities concerned only with their own replication and survival.

Contrasting effects of catecholic and O-methylated tetrahydroisoquinolines on hydroxyl radical production

Tetrahydroisoquinolines (TIQs) are intraneuronal, catecholamine-derived alkaloids that have been implicated in the etiology of Parkinson's disease and in alcohol related disorders. The in vitro production of the cytotoxic hydroxyl radical (*OH) was recorded during the autoxidation of salsolinol (SAL) and salsolinol-1-carboxylic acid (SAL-1C), but not when these two catecholic TIQs were oxidized by tyrosinase. Significantly higher levels of the radical were produced when these catecholic TIQs were incubated with *OH generating complexes, or with chelated iron. In contrast, mono-O-methylated TIQs such as salsoline (SLN) and salsoline-1-carboxylic acid (SLN-1C) did not generate *OH during autoxidation or when incubated with chelated iron or tyrosinase. Radical production by *OH-generating complexes was reduced in the presence of O-methylated TIQs. The neurotoxicity of TIQs may result from their propensity to autoxidize and generate reactive quinoids and ensuing oxygen radicals. The functional significance of the replacement of a hydroxyl group attached to C-7 of SAL or SAL-1C with a methoxyl group remains to be determined. This single structural modification may prevent mono-O-methylated TIQs from participating in catalytic redox cycling reactions that would otherwise augment *OH production. If true, then O-methylation and other cellular mechanisms that circumvent the autoxidation of catecholamine-derived TIQs may reduce the likelihood of these substances forming cytotoxic quinoids and influencing endogenous *OH-generating reactions.

Evaluation of the BOD POD for assessing body fat in collegiate football players

PURPOSE

The purpose of this investigation was to evaluate the accuracy of a new air displacement plethysmograph, BOD POD Body Composition System, for determining %fat in collegiate football players.

METHODS

Body fatness was estimated from body density (Db), which was measured on the same day using the BOD POD and hydrostatic weighing (HW) in 69 Division IA football players. In addition, 20 subjects were whole body scanned using dual-energy x-ray absorptiometry, DXA (Lunar DPX-L) to assess total body mineral content and %fat. Mineral content and HW determined Db were used to compute %fat from a three-component model (3C; fat, mineral, and residual).

RESULTS

Test-retest reliability for assessing %fat using the BOD POD (N = 15) was 0.994 with a technical error of measurement of 0.448%. Mean (+/- SEM) Db measured with the BOD POD (1.064 +/- 0.002 g x cc(-1) was significantly greater (P < 0.05) than HW (1.060 +/- 0.002 g x cc(-1)), thus resulting in a lower %fat for the BOD POD (15.1 +/- 0.8%) compared with HW (17.0 +/- 0.8%). Similar results (N = 20) were found for DXA (12.9 +/- 1.2%) and the 3C (12.7 +/- 0.8%) where %fat scores were significantly higher (P < 0.05) than scores determined using the BOD POD (10.9 +/- 1.0%).

CONCLUSIONS

Db measured with the BOD POD was higher than the criterion HW, thus yielding lower %fat scores for the BOD POD. In addition, BOD POD determined %fat was lower than DXA and 3C determined values in a subgroup of subjects. Assessment of %fat using the BOD POD is reliable and requires minimal technical expertise; however, in this study of collegiate football players, %fat values were underpredicted when compared to HW, DXA, and the 3C model.

Dental anomalies associated with amelogenesis imperfecta: a radiographic assessment

Amelogenesis imperfecta, a group of hereditary conditions primarily affecting the enamel, has been associated with dental anomalies, including taurodontism, congenitally missing teeth, delayed eruption, crown resorption, and abnormal enamel density. The purpose of this study was to assess the prevalence of these anomalies in an amelogenesis imperfecta population. The study group consisted of members of 9 unrelated families--22 family members with amelogenesis imperfecta and 13 unaffected family members. Panoramic radiographs were evaluated for taurodontism, congenitally missing teeth, delayed tooth eruption, pathologic dental resorption, pulp calcification, and radiographic enamel density. The prevalence of taurodontism was similar in people with amelogenesis imperfecta and normal people; all of the remaining parameters were more commonly observed in people with amelogenesis imperfecta. The radiographic enamel density was quantitatively reduced in teeth affected by amelogenesis imperfecta in comparison with teeth with normal enamel. These findings suggest that some of the features associated with amelogenesis imperfecta result from abnormal enamel formation (eg, decreased enamel density, crown resorption) whereas others may occur as a result of expression of the genetic mutation in cells other than ameloblasts (eg, abnormal eruption, pulp calcification).

Multiplicity of glutamic acid decarboxylases (GAD) in vertebrates: molecular phylogeny and evidence for a new GAD paralog

The evolution of chordate glutamic acid decarboxylase (GAD; EC 4.1.1.15), a key enzyme in the central nervous system synthesizing the neurotransmitter gamma-amino-butyric acid (GABA) from glutamate, was studied. Prior to this study, molecular data of GAD had been restricted to mammals, which express two distinct forms, GAD65 and GAD67. These are the products of separate genes and probably are derived from a common ancestral GAD following gene duplication at some point during vertebrate evolution. To enable a comprehensive phylogenetic analysis, molecular information of GAD forms in other vertebrate classes was essential. By reverse transcriptase-polymerase chain reaction (RT-PCR), partial nucleotide sequences of GAD were cloned from brains of zebra finch (Taeniopygia guttata), turtle (Trachemys scripta), goldfish (Carassius auratus), zebrafish (Danio rerio), and armoured grenadier (Coryphaenoides (Nematonurus) armatus, a deep-sea fish), and from the cerebral ganglion plus neural gland of Ciona intestinalis, a protochordate. Whereas GAD65 and GAD67 homologs were expressed in birds, reptiles, and fish, only a single GAD cDNA with equal similarities to both vertebrate GAD forms was found in the protochordate. This indicates that the duplication of the vertebrate GAD gene occurred between 400 and 560 million years ago. For both GAD65 and GAD67, the generated phylogenetic tree followed the general tree topology for the major vertebrate classes. In turtle, an alternative spliced form of GAD65, putatively encoding a truncated, nonactive GAD, was found. Furthermore, a third GAD form, which is equally divergent from both GAD65 and GAD67, is expressed in C. (N.) armatus. This third form might have originated from an ancient genome duplication specific to modern ray-finned fishes.

Bright, bad, babyfaced boys: appearance stereotypes do not always yield self-fulfilling prophecy effects

Three studies tested the hypothesis that babyfaced adolescent boys would compensate for the undesirable expectation that they will exhibit childlike traits by behaving contrary to it. Studies 1 and 2 revealed that babyfaced boys from middle- and lower class samples, including a sample of delinquents, showed higher academic achievement than their mature-faced peers, refuting the stereotype of babyfaced people as intellectually weak. In the lower class samples, this compensation effect was moderated by IQ and socioeconomic status (SES), variables that influence the ability to overcome low expectations. Study 3 showed that babyfaceness also can produce negative compensatory behaviors. Low-SES babyfaced boys were more likely than their mature-faced peers to be delinquent, and babyfaced delinquents committed more crimes, refuting the stereotype of babyfaced people as warm, submissive, and physically weak.

Effect of weight training exercise and treadmill exercise on post-exercise oxygen consumption

Effect of weight training exercise and treadmill exercise on postexercise oxygen consumption. Med. Sci. Sports Exerc., Vol. 30, No. 4, pp. 518-522, 1998. To compare the effect of weight training (WT) and treadmill (TM) exercise on postexercise oxygen consumption (VO2), 15 males (mean +/- SD) age = 22.7 +/- 1.6 yr; height = 175.0 +/- 6.2 cm; mass = 82.0 +/- 14.3 kg) performed a 27-min bout of WT and a 27-min bout of TM exercise at matched rates of VO2. WT consisted of performing two circuits of eight exercises at 60% of each subject's one repetition maximum with a work/rest ratio of 45 s/60 s. Approximately 5 d after WT each subject walked or jogged on the TM at a pace that elicited an average VO2 matched with his mean value during WT. VO2 was measured continuously during exercise and the first 30 min into recovery and at 60 and 90 min into recovery. VO2 during WT (1.58 L.min-1) and TM exercise (1.55 L.min-1) were not significantly (P > 0.05) different; thus the two activities were matched for VO2. Total oxygen consumption during the first 30 min of recovery was significantly higher (P < 0.05) as a result of WT (19.0 L) compared with that during TM exercise (12.7 L). However, VO2 values at 60 (0.32 vs 0.29 L.min-1), and 90 min (0.33 vs 0.30 L.min-1) were not significantly different (P > 0.05) between WT and TM exercise, respectively. The results suggest that, during the first 30 min following exercise. WT elicits a greater elevated postexercise VO2 than TM exercise when the two activities are performed at matched VO2 and equal durations. Therefore, total energy expenditure as a consequence of WT will be underestimated if based on exercise VO2 only.