Bacterial community structure and response to nitrogen amendments in Lake Shenandoah (VA, USA).

Microbial processes are critical to the function of freshwater ecosystems, yet we still do not fully understand the factors that shape freshwater microbial communities. Furthermore, freshwater ecosystems are particularly susceptible to effects of environmental change, including influx of exogenous nutrients such as nitrogen and phosphorus. To evaluate the impact of nitrogen loading on the microbial community structure of shallow freshwater lakes, water samples collected from Lake Shenandoah (Virginia, USA) were incubated with two concentrations of either ammonium, nitrate, or urea as a nitrogen source. The potential impact of these nitrogen compounds on the bacterial community structure was assessed via 16S rRNA amplicon sequencing. At the phylum level, the dominant taxa in Lake Shenandoah were comprised of Actinobacteria and Proteobacteria, which were not affected by exposure to the various nitrogen treatments. Overall, there was not a significant shift in the diversity of the bacterial community of Lake Shenandoah with the addition of nitrogen sources, indicating this shallow system may be constrained by other environmental factors.

Paleoclimatological analysis of late quaternary cores from the northeastern gulf of Mexico.

Oxygen isotopic, radiocarbon, and micropaleontological analysis of deep-sea cores from the northeastern Gulf of Mexico identify an episode of rapid ice melting and sea-level rise at about 9600 years B.C. This age coincides, within the limits of all errors, with the age of the Valders ice readvance and with the age assigned by Plato to the flood he describes.

Comparison of L-758,298, a prodrug for the selective neurokinin-1 antagonist, L-754,030, with ondansetron for the prevention of cisplatin-induced emesis.

Substance P is localised in brainstem regions associated with emesis. Based on studies in the ferret, it was postulated that a neurokinin-1 (NK1) receptor antagonist would have antiemetic activity as monotherapy in humans receiving chemotherapy. L-758,298 is a water-soluble, intravenous (i.v.) prodrug for L-754,030, a potent and selective NK1 receptor antagonist. This double-blind, randomised, active-agent (ondansetron)-controlled study enrolled 53 cisplatin-naïve patients and evaluated the prevention of both acute (0-24 h) and delayed (days 2-7) emesis after cisplatin treatment (50-100 mg/m(2)). All patients received i.v. L-758,298 (60 or 100 mg) (n=30) or ondansetron (32 mg) (n=23) before cisplatin and efficacy was evaluated up to day 7 post-cisplatin. Nausea was assessed by means of a four-point ordinal scale at intervals over the 7 day period. In the acute period, the proportion of patients without emesis in the L-758,298 and ondansetron groups was 37 and 52%, respectively (no significant difference between the groups). Comparing the distribution of average nausea scores over the entire first 24 h revealed no significant difference between the groups. In the delayed period, the proportion of patients without emesis in the L-758,298 and ondansetron treatment groups was 72 and 30%, respectively (P=0.005). The distribution of average nausea scores in the delayed period was lower in the L-758,298 group compared with the ondansetron group (P=0.15 for the entire delayed period and P=0.043 for day 2 only). No serious adverse events were attributed to L-758,298. A single dose of L-758,298 substantially suppressed the delayed nausea and vomiting characteristic of high dose cisplatin and also appeared to reduce acute emesis post-cisplatin. The data also support the proposition that the underlying mechanism(s) of acute and delayed emesis are different.

The enhancement of traditional behavioral couples therapy: consideration of individual factors and dyadic development.

There has been little effort by behavior therapists to develop couple interventions that view marriage from a content-relevant or developmental perspective. Consequently, we have delineated ways in which a perspective of intimate relationships including individual factors and dyadic development might guide the enhancement of traditional behavioral couples therapy (TBCT) with novel and improved techniques that will ultimately allows us to reach a wider range of distressed couples than our current interventions allows. Specifically, we examined the potential benefits to intervention that could occur by considering the impact of individual factors on relationship quality, using the literature on attachment patterns as an example. Further, we have discussed the potential gains to couple interventions that could occur by considering the impact of dyadic development on relationship satisfaction. We first addressed gradual changes in marriage, using intimacy as an example. Next we examined "stage of marriage" issues, using child behavior problems as an example. Finally, we considered whether or not a problem was chronic. Throughout, we have proposed utilizing TBCT as a starting point, and considering ways to enhance TBCT specifically, as it is the marital therapy for which we have the most information and empirical support.

Integrative behavioral couple therapy: an acceptance-based, promising new treatment for couple discord.

Although traditional behavioral couple therapy (TBCT) has garnered the most empirical support of any marital treatment, concerns have been raised about both its durability and clinical significance. Integrative behavioral couple therapy (IBCT) was designed to address some of these limitations by combining strategies for fostering emotional acceptance with the change-oriented strategies of TBCT. Results of a preliminary clinical trial, in which 21 couples were randomly assigned to TBCT or IBCT, indicated that therapists could keep the 2 treatments distinct, that both husbands and wives receiving IBCT evidenced greater increases in marital satisfaction than couples receiving TBCT, and that IBCT resulted in a greater percentage of couples who either improved or recovered on the basis of clinical significance data. Although preliminary, these findings suggest that IBCT is a promising new treatment for couple discord.

Evidence-based practice. Slow-acting remedy.

A survey of community trusts in North Thames found little evidence of a general move towards evidence-based practice. Half the clinicians Interviewed claimed that their managers had no knowledge of their research projects and the findings of their research were not disseminated. More than half the clinicians interviewed had not read the NHS R&D strategy. Managers and clinicians both need training in research skills. Some doctors and many nurses felt the current research strategy was unfavourable to qualitative studies.

A new species of Myrmedonota Cameron from eastern Kansas (Coleoptera, Staphylinidae, Aleocharinae).

Myrmedonota helianthasp. n. is described from eastern Kansas (USA). All specimens were collected from dung. A modified new key to the species of Myrmedonota of America north of Mexico is provided.

Does the clinical outcome of hepatitis C infection vary with the infecting hepatitis C virus type?

Whether differences in the natural history of hepatitis C virus (HCV) can be explained by differences in the infecting HCV type is unknown. The aim of this study was to investigate whether the HCV type might influence the clinical outcome of infection. Study serum samples were assembled from 749 individuals enrolled into the UK HCV National Register from which data on clinical outcomes were extracted. HCV-RNA-positive specimens were genotyped and HCV-RNA-negative specimens serotyped. Logistic regression analysis was used to investigate the independent effect of HCV type on viral clearance by comparing patients who were HCV RNA negative (n = 86) with those who were HCV RNA positive (n = 508). The same method was used to investigate whether HCV type was associated with histological stage of liver disease. The prevalence of HCV type 1 among those who cleared infection was 69% and among those who remained HCV RNA positive was 51%: Type 1 infections were more likely to be HCV RNA negative than non-1 types (OR 0.47, 95% CI 0.29-0.78, P = 0.003). Type 1 infections were also more likely to be associated with histological stage scores above the median when compared with non-1 types (OR 2.03, 95% CI 1.07-3.83, P = 0.03). In conclusion, HCV type 1 infection was more often HCV RNA negative, suggesting that spontaneous clearance may occur more commonly with this type. Among the RNA-positive infections, type 1 infection may be more aggressive than types 2/3.

Dental caries prevalence and dental health behaviour in HIV infected children.

OBJECTIVES: To determine dental caries prevalence in a group of HIV positive children and their reported dental health behaviour. DESIGN: Standardized epidemiological dental examination and structured interview. SETTING: Paediatric HIV outpatient department in a South London hospital. STUDY POPULATION: HIV-positive children attending the above outpatient clinic over a 6-month period (30 subjects) and parents (20 informants). METHODS: Epidemiological examination of children was undertaken by one trained and calibrated examiner to determine caries prevalence using dmft/DMFT. Parents were interviewed to obtain information on their children's dental health behaviour: toothbrushing, diet, fluoride; oral medication and dental attendance were explored. RESULTS: Sixty-three per cent (n = 19) of children had dental caries experience, much of it untreated. Mean dmft/DMFT was 4.4. Sixty per cent (n = 18) of all children presented with active or untreated caries and the care index for those at/under age 5 years was low (10%). Unfavourable dental health behaviour included: consumption of nonmilk extrinsic sugars at night, use of sugar-based medications, low fluoride intake, late commencement of toothbrushing and poor dental attendance. Dental health was not considered a priority for many of these children. Parents did not necessarily disclose their child's HIV status on dental attendance. CONCLUSION: Caries prevalence was high, much of the disease untreated, and unfavourable dental health behaviour, including the use of sugar-based medicines was common. HIV infected children should be considered a high caries risk and receive appropriate dental care, in terms of both treatment and preventive services, following confirmation of seropositivity.

Heparan sulfate proteoglycans in the substratum adhesion sites of human neuroblastoma cells: modulation of affinity binding to fibronectin.

Tissue culture substratum adhesion sites from EGTA-detached Platt human neuroblastoma cells were extracted with a buffer containing ocytlglucoside, NaCl, guanidine hydrochloride, and a variety of protease inhibitors, an extraction which resulted in quantitative solubilization of the 35SO4 = -radiolabeled proteoglycans and 3H-leucine-radiolabeled proteins. Of the sulfate-radiolabeled material, the vast majority was heparan sulfate proteoglycan (Kav = 0.15 on Sepharose C14B columns) and the remainder was chondroitin sulfate chains (no single chains of heparan sulfate were observed). This extract was then fractionated on DEAE-Sephadex columns under two different buffer elution conditions. Under DEAE-I conditions in low ionic strength acetate buffer, two major peaks of 35SO4 = -radiolabeled material (A,B) and a minor peak (C) could be resolved in the NaCl gradient; however, three-fourths of the material required 4 M guanidine hydrochloride to elute it from the column (peak D). Under DEAE-II conditions in acetate buffer supplemented with 8 M urea, the vast majority of the proteoglycan material could be eluted in the NaCl gradient as peak AB. Peak D material was shown to contain aggregated proteoglycan, along with nonproteoglycan protein, which high concentrations of urea or guanidine could dissociate, but not nonionic or zwitterionic detergents. Three different affinity chromatography systems were used to further characterize these components. Approximately 60% of peak A heparan sulfate proteoglycan from DEAE-I binds to the hydrophobic matrix, octyl-Sepharose, while 80% of the proteoglycan in DEAE-I peak D binds to this hydrophobic column. A sizable fraction of peak A proteoglycan fails to bind to plasma fibronectin but does bind to platelet factor-4 affinity columns. In contrast, peak AB proteoglycan from DEAE-II columns yields a much higher proportion of molecules which do bind to fibronectin. To examine the basis for these differences in affinity binding, nonproteoglycan protein from these adhesion sites was mixed with peak AB proteoglycan prior to affinity chromatography; proteoglycan binding to fibronectin decreased markedly while binding to platelet factor-4 was unaffected. This modulating activity involves the binding of nonproteoglycan protein in adhesion site extracts to both fibronectin on the column, as well as to heparan sulfate proteoglycan itself, and it could not be mimicked by a number of known proteins in adhesion site extracts or several other proteins. These results demonstrate selectivity and specificity in this modulation and indicate that a previously unidentified protein(s) is responsible.(ABSTRACT TRUNCATED AT 400 WORDS)

Characterization of membrane-bound electron transport enzymes from castor bean glyoxysomes and endoplasmic reticulum.

Membranes purified from castor bean endosperm glyoxysomes by washing with sodium carbonate exhibited integral NADH:ferricyanide and NADH:cytochrome c reductase activities. The enzyme activities could not be attributed to contamination by other endomembranes. Purified endoplasmic reticulum membranes also contained the redox activities; and marker enzyme analysis indicated minimum cross contamination between glyoxysomal and endoplasmic reticulum fractions. The glyoxysomal redox activities were optimally solubilized at detergent to protein ratios (weight to weight) of 10 (Triton X-100), 50 (3-[3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate), and 100 (octylglucoside). Detergent in excess of the solubilization optimum was stimulatory to NADH:ferricyanide reductase and inhibitory to NADH:cytochrome c reductase. Endoplasmic reticulum redox activity solubilization profiles were similar to those obtained for glyoxysomal enzymes using Triton X-100. Purification of the glyoxysomal and endoplasmic reticulum NADH:ferricyanide reductases was accomplished using dye-ligand affinity chromatography on Cibacron blue 3GA agarose. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of NADH:ferricyanide reductase preparations purified by rate-zonal density gradient centrifugation, affinity chromatography, and nondenaturing electrophoresis of detergent-solubilized glyoxysomal and endoplasmic reticulum membranes consistently displayed 32- and 33-kDa silver-stained polypeptide bands, respectively.

The HCV National Register: towards informing the natural history of hepatitis C infection in the UK.

The aim of this paper is to describe the development of a national hepatitis C register and the completeness of the data it contains. This is a descriptive report of the structure and function of the register, including case definitions, registration and follow-up procedures, and methods used to maximize data quality and to obtain comparative data sources. The register contains data on HCV-infected individuals who acquired their infections on a known date and by a known route; to date all are transfusion recipients identified during the UK lookback exercise, who tested positive or indeterminate for anti-HCV after receiving 'infected' blood issued before the introduction of routine testing of the blood supply for anti-HCV. By 31 December 1999, 871 (87%) of 996 eligible transfusion recipients had been registered, and 984 (99%) flagged in the NHS Central Registers. Registered patients had been infected for an average of 11.1 years (SEM 0.1); around half were being cared for by clinicians with a specialist interest in liver disease. Except for the information on tobacco use, current alcohol use, and hepatitis B status, data were more than 80% complete, and for most variables, more than 90% complete. The consistency of data abstraction was found to be 98% (SEM 0.5). In conclusion, the Register contains high quality anonymised data on one of the largest cohorts of individuals with HCV infections acquired on a known date and by a known route. It could serve as a model for other chronic disease registers; developers may find the structure, design, and methodological issues addressed useful.

Efficacy of an alcohol-free chlorhexidine mouthrinse as an antimicrobial agent.

STATEMENT OF PROBLEM: Antimicrobial mouthrinses have become an important part of comprehensive dental care. However, mouthrinses that contain alcohol have been shown to be detrimental to patients undergoing radiation therapy for head and neck cancer, to some immunocompromised patients, to families with small children, and to persons sensitive to alcohol. PURPOSE: This study evaluated the effectiveness of alcohol-free, 0.12% chlorhexidine mouthrinse in reducing microbial levels when compared with commercially available 0.12% chlorhexidine (CHX) and essential oils mouthrinses. MATERIAL AND METHODS: This study consisted of both in vitro and in vivo investigations. The double-blind study included 32 subjects randomly assigned to 3 groups, equalized according to the indices tested. One group (n = 11) received essential oils rinse; the second group (n = 11) received CHX; and the last group (n = 10) received the alcohol-free CHX. Subjects were asked not to use any mechanical means of oral hygiene for 21 days. The in vitro part of the study consisted of Streptococcus mutans strip tests. RESULTS: Mean plaque scores for both CHX products decreased after 21 days, whereas the mean for the essential oils increased. Bleeding and gingival index scores for all 3 groups increased, which may be due to the initially healthy tissues of the participants. Relative microbial growth for S mutans for both the CHX products decreased to 0 after 21 days, whereas the counts for the essential oils group remained varied.