Terminal cretaceous extinctions in the hell creek area, montana: compatible with catastrophic extinction

Inaccurate stratigraphic correlations in the Hell Creek area, Montana, have led to the assumption that transitional vertebrate faunas (Bug Creek Anthills) exist in the latest Cretaceous, refuting a catastrophic turnover at the Cretaceous-Tertiary boundary. Establishment of the transitional faunas in Paleocene channels that cut down through the Cretaceous-Tertiary boundary renders the terrestrial faunal record compatible with the marine record and with catastrophic extinction.

Characterization of In Vivo Reporter Systems for Gene Expression and Biosensor Applications Based on luxAB Luciferase Genes

Advances in genetic engineering methods have allowed the development of an increasing number of practical and scientific applications for bioluminescence with lux genes cloned from a variety of organisms. Bioluminescence derived from the shortened lux operon (luxAB genes) is a complex process, and applications seem to be proliferating in advance of an understanding of the underlying biochemical processes. In this report, we describe a two-phase kinetic behavior of the light emission which must be properly taken into account in any quantitative measurements of the bioluminescence signal. By using strains of Escherichia coli and Caulobacter crescentus, this behavior was characterized and interpreted in terms of the biochemistry underlying the bacterial luciferase mechanism. We show that the intensity profile of each of the two phases of the luminescence signal is responsive (and exhibits different sensitivities) to the concentration of added decanal and other components of the assay mix, as well as to the order of mixing and incubation times. This study illustrates the importance of appropriate protocol design, and specific recommendations for using the luxAB system as a molecular reporter are presented, along with versatile assay protocols that yield meaningful and reproducible signals.

Validity of the K-10 in detecting DSM-IV-defined depression and anxiety disorders among HIV-infected individuals

It has been suggested that an HIV diagnosis may increase the likelihood of mental disorders among infected individuals and that the progression of HIV may be hastened by mental disorders like anxiety and depression. Therefore, a brief screening measure, with good sensitivity/specificity for psychiatric diagnoses that could be given to HIV-infected individuals would be useful. We assessed the validity of the K-10, using the MINI International Neuropsychiatric Interview as the gold standard, in a sample of 429 HIV-infected adults enrolled in HIV care and treatment services near Cape Town, South Africa. There was significant agreement between the K-10 and the MINI-defined depressive and anxiety disorders. A receiver operating characteristic (ROC) curve analysis indicated that the K-10 showed agreeable sensitivity and specificity in detecting depression (area under the ROC curve, 0.77), generalized anxiety disorder (0.78), and posttraumatic stress disorder (PTSD) (0.77). The K-10 may be a useful screening measure for detecting mood and anxiety disorders, including PTSD, in patients with HIV/AIDS.

Double Blind Randomised Clinical Trial of Bright Light Therapy in Elderly Subjects with Nonseaonal Major Depressive Disorder

Background:

The cause of depression is largely unknown, but several studies point to disturbances of biological rhythmicity. The functioning of the suprachiasmatic nucleus (SCN) is impaired, as evidenced by an increased prevalence of day-night rhythm perturbations, such as sleeping disorders. Moreover, the inhibitory SCN neurons on the hypothalamus-pituitary adrenocortical axis (HPA-axis) have decreased activity and HPA-activity is enhanced, when compared to non-depressed elderly. Using bright light therapy (BLT) the SCN can be stimulated. In addition, the beneficial effects of BLT on seasonal depression are well accepted. BLT is a potentially safe, nonexpensive and well accepted treatment option. But the current literature on BLT for depression is inconclusive.

Methods/design:

RCT (ClinicalTrials.gov identifier: NCT00332670) in 89 subjects, of 60 years and older with a diagnosis of major depressive disorder. After inclusion subjects were randomly allocated to the active (BLT) vs. placebo (dim red light) condition. just before the start of light therapy, after completion of three weeks therapy period, and three weeks thereafter several endocrinological, psychophysiological, psychometrically, neuropsychological measures are performed:

Results:

Main effect analyses on HADRS-17 scores revealed significant antidepressant effects from BLT. Primary results will be presented.

Discussion:

BLT reduces nonseasonal depression in elderly patients. Additional lightning may easily be implemented in the homes of patients to serve as add-on treatment to antidepressants or as a stand-alone treatment in elderly depressed patients. Our data support the role of a dysfunctional biological clock in depressed elderly subjects, such a finding may guide further development of novel chronobiological oriented treatment strategies.

Translation and cross-cultural adaptation of a mental health battery in an African setting

BACKGROUND

Standardised measuring instruments are increasingly used in psychiatric research cross-culturally. These instruments are considered to be culturally equivalent when all forms of biases, or social norms specific to the culture of origin, have been removed.

OBJECTIVES

To describe the qualitative process of selection, translation and cultural adaptation of a mental health battery for use in a Xhosa-speaking community that is, as far as possible, 'culture-free' or equivalent.

METHOD

Informal discussions were held with key members in the community to determine what would be considered as appropriate for the community in respect of psychiatric screening instruments. Existing rating-scales for depression, alcohol abuse and posttraumatic stress disorder that would meet these criteria were identified and then translated from English into Xhosa. Cultural equivalence was achieved by combining methods of back-translation, committee consensus approach and decentering. Discussions during the committee consensus meetings were recorded and categorized into themes. Two themes emerged: (1) issues related to the attainment of semantic equivalence and (2) broader problems inherent in cross-cultural research.

RESULTS

Issues related to individual questionnaires included the use of terms to describe emotional distress cross-culturally. Broader issues related to the translation process itself included the form of language to be used, time-frames, and the use of Likert-scales. It also demonstrated the problems inherent in the categorization of emotions.

CONCLUSION

A method of combining a group approach, back-translation, and decentering was effective and efficient in this context for establishing content and semantic equivalence. Cross-cultural adaptation can never completely remove all forms of bias from a research instrument, but such limitations should be acknowledged and openly discussed, rather than hidden or ignored.

Sexual risk factors associated with volunteering for HIV vaccine research in South Africa

There are few data on how the risk profiles of individuals who volunteer for HIV vaccine research compare to the general population from which participants are recruited. This study contrasts demographic and sexual risk behaviours among volunteers in an HIV vaccine preparedness cohort with data from a cross-sectional community survey conducted in the same peri-urban community during the same time period. For the HIV vaccine preparedness cohort, structured questionnaires were administered to 140 HIV-negative individuals aged between 16 and 40 years. A questionnaire with identical measures was self-administered in a cross-sectional community survey of 583 randomly selected individuals within the same age range. Compared to the local community sample, individuals who volunteered for the HIV vaccine preparedness cohort were younger (adjusted odds ratio = 0.48; 95% CI = 0.28-0.82), more likely to have had a sexually transmitted disease (adjusted odds ratio = 1.75; 95% CI = 1.03-2.99) and less likely to use condoms (adjusted odds ratio = 0.51; 95% CI = 0.3-0.86). Cohort participants were also more likely to perceive themselves and their partners to be at risk of HIV infection, though these associations did not persist in multivariate analysis. These findings suggest that volunteers for vaccine-related research may be at greater risk of HIV infection than the general population from which they are recruited.

Depot medroxyprogesterone versus norethisterone oenanthate for long-acting progestogenic contraception

BACKGROUND

There are two injectable progestogen-only contraceptives (IPCs) that have been available in many countries in the world since 1983. They are both still extensively used in many developing countries, forming a large proportion of the health system's expenditure on contraception. These are depot medroxyprogesterone acetate (DMPA) and norethisterone oenanthate (NET-EN). These are both highly effective contraceptives that receive wide acceptance amongst women in their fertile years. They differ in frequency of administration that has implications on patient uptake. They also differ in cost that may significantly affect budgeting in the health system. A systematic comparison will aid to ensure their rational use.

OBJECTIVES

To determine if there are differences between depot medroxyprogesterone acetate given at a dose of 150 mg IM every 3 months and norethisterone oenanthate given at a dose of 200mg IM every 2 months, in terms of contraceptive effectiveness, reversibility and discontinuation patterns, minor effects and major effects.

SEARCH STRATEGY

We searched the computerized databases MEDLINE using PubMed, Popline, Cochrane Controlled Trials Register, Biblioline, LILACS, EMBASE and PASCAL for randomised controlled trials of DMPA versus NET-EN for long-acting progestogenic contraception. Studies were included regardless of language, and all databases were reviewed from the time that injectable progestogens have been in use.

SELECTION CRITERIA

All randomised controlled comparisons of DMPA acetate given at a dose of 150 mg IM every 3 months versus NET-EN given at a dose of 200mg IM every 2 months, used for contraception, were included. Trials had to report on contraceptive efficiency and return to fertility, discontinuation risks and reasons for discontinuation, and clinical effects, both menstrual and non-menstrual.

DATA COLLECTION AND ANALYSIS

BD and CM evaluated the titles and abstracts obtained through applying the search strategy and applied the eligibility criteria. BD attempted to contact authors where clarification of the data was required, and contacted all main manufacturers of the contraceptives. After inclusion of the two studies, the data was abstracted and analysed with RevMan 4.2.

MAIN RESULTS

Two trials were included in this review. There was no significant difference between the two treatment groups for the frequency of discontinuation for either contraceptive, although the women on NET-EN were 4% more likely to discontinue for personal reasons than those on DPMA. Discontinuation because of accidental pregnancy did not differ between the groups. Although the duration of bleeding and spotting events was the same in each group, women on DPMA were 21% more likely to develop amenorrhoea. Mean changes in body weight at 12 and 24 months, and in systolic and diastolic blood pressure at 12 months did not differ significantly between the studies.

AUTHORS' CONCLUSIONS

While the choice between DPMA and NET-EN as injectable progestogen contraceptives may vary between both health providers and patients, data from randomized controlled trials indicate little difference between the effects of these methods, except that women on DMPA are more likely to develop amenorrhoea. There is inadequate data to detect differences in some non-menstrual major and minor clinical effects.

Willingness to participate in HIV vaccine research in a peri-urban South African community

Research on willingness to participate in HIV vaccine trials is important in preparations for HIV vaccine research, but there are few data from sub-Saharan Africa. We interviewed 198 individuals in a peri-urban South African community immediately after enrolment into an HIV vaccine preparedness study on their willingness to participate in hypothetical vaccine trials. Overall 23% of participants (n = 46) said that they would be willing to participate in an HIV vaccine trial. Willingness was associated with increasing age, male gender, and increasing knowledge about vaccines generally and HIV vaccines specifically. In multivariate analysis, a 1-unit increase in HIV vaccine knowledge score was associated with a 10-fold increase in willingness to participate (adjusted odds ratio, 10.72, 95% confidence intervals: 4.40-26.12). These results suggest that while willingness to participate in HIV vaccine trials is relatively low in this setting, educational campaigns may have a substantial impact on individuals' willingness to participate in research.

Mental health and sexual risk behaviours in a South African township: A community-based cross-sectional study

OBJECTIVES

Despite the high prevalence of both mental illness and human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) in developing countries, there are few data on the association between different forms of mental illness and sexual risk behaviours in resource-poor settings. The objective of this study was to examine the association between mental illness and HIV risk behaviours in a South African township.

STUDY DESIGN

A cross-sectional study was performed among 645 individuals living in households selected at random.

METHODS

A self-administered translated questionnaire investigated sexual risk behaviours [including sexual partners, condom use, casual sexual contacts, and sex in exchange for money, drugs or a place to stay (transactional sex)], depression (measured using the Center for Epidemiological Studies Depression Scale), alcohol abuse (from the Alcohol Use Disorders Identification Test), and post-traumatic stress disorder (based on the Life Event Checklist).

RESULTS

Of the 645 individuals who completed the survey, 33% reported depression, 17% reported alcohol abuse, and 15% reported post-traumatic stress disorder. After adjusting for demographic characteristics, the presence of any of these three conditions was strongly associated with experiences of forced sex [adjusted odds ratio (AOR) 2.53; 95% confidence intervals (CI) 1.60-4.02], transactional sex (AOR 2.88; 95% CI 1.29-6.48) and increased condom use (AOR 2.07; 95% CI 1.32-3.25).

CONCLUSIONS

These findings emphasize the substantial burden of mental illness in this setting, and its association with forced and transactional sex. The temporal nature of these associations is not always clear from this cross-sectional study, and additional prospective research is required. Public health interventions are needed to address the dual burden of HIV/AIDS and mental illness in this and similar settings.

Anti-tumor effects of the bacterium Caulobacter crescentus in murine tumor models

Caulobacter crescentus is a gram negative, non-pathogenic bacterium, common in aquatic and soil environments. One feature of note is a protein surface layer (S-layer) composed of a single protein, organized as a self-assembled crystalline array that coats the bacterium. In the course of efforts to express cancer-associated peptides as genetic insertions into the S-layer, we noted a tumor suppressive effect of the unmodified bacterium. C. crescentus was examined for anti-tumor activity against three transplantable tumor mouse models: Lewis lung carcinoma cells transfected with the MUC1 gene in C57BL/6, murine mammary carcinoma (EMT-6) in BALB/c (both in prophylactic and therapeutic mode) and murine leukemia cells (L1210) in DBA2. Mice were immunized three times i.p. with C. crescentus (2 x 10(7) cells/mouse). In prophylactic mode, the mice were challenged with tumor cells two weeks after the last immunization. Immunization with live C. crescentus resulted in anti-tumor activity in all three transplantable tumor models, as measured by prolonged survival, reduced tumor mass or reduced number of lung nodules, compared to saline control groups. In the Lewis lung and the EMT-6 mammary carcinoma murine models the number of lung nodules as well as the tumor weight was lower in mice treated with C. crescentus, compared to the control group; for EMT-6, this was observed in prophylactic and therapeutic modes. In the murine leukemia and Lewis lung carcinoma models prolonged survival was observed in the groups of mice immunized with Caulobacters. In most cases the live C. crescentus cells were markedly more efficacious than heat killed or formalin fixed cells, despite the fact that they do not grow or persist in mice. The results suggest that C. crescentus may be a safe, bacterial immunomodulator for the treatment of tumors.

Influence of dentifrices and dietary components in saliva on wettability of pellicle-coated enamel in vitro and in vivo

In vitro salivary pellicles were found to be less hydrophobic by water contact angles than clinically formed pellicles. In this study, water contact angles were measured on enamel coated with pellicles adsorbed from reconstituted human whole saliva (RHWS) and after exposure to dentifrices or dietary components. In addition, adhesion of Streptococcus oralis J22 to pellicles formed from RHWS with minor amounts of milk added and after exposure to dentifrices was studied. Exposure of RHWS-pellicles to milk or salad oil yielded an increase in the hydrophobicity of in vitro pellicles to values observed in vivo, but a decrease was seen after exposure to a sugar solution. Pellicles formed from saliva with 0.4% milk added attracted less S. oralis cells than pellicles formed in the absence of milk components. Exposure of pellicles formed from saliva with milk added to various dentifrices had a variable effect on bacterial adhesion: markedly lower numbers of adhering S. oralis were found for a dentifrice with NaF, but exposure to dentifrices containing SnF2 or hexametaphosphate showed slightly increased adhesion. In summary, dietary components have influence on the hydrophobicity of enamel pellicles, while combinations of dietary components and dentifrices certainly influence the adhesiveness of the pellicles. The effects of dietary components on pellicle conditioning film should be taken into consideration in research on the development of ingredients to control intraoral surface chemistry and microbiology, as well as in the development of oral products.