Characterization of Hydrogen Metabolism in the Multicellular Green Alga Volvox carteri.

Hydrogen gas functions as a key component in the metabolism of a wide variety of microorganisms, often acting as either a fermentative end-product or an energy source. The number of organisms reported to utilize hydrogen continues to grow, contributing to and expanding our knowledge of biological hydrogen processes. Here we demonstrate that Volvox carteri f. nagariensis, a multicellular green alga with differentiated cells, evolves H2 both when supplied with an abiotic electron donor and under physiological conditions. The genome of Volvox carteri contains two genes encoding putative [FeFe]-hydrogenases (HYDA1 and HYDA2), and the transcripts for these genes accumulate under anaerobic conditions. The HYDA1 and HYDA2 gene products were cloned, expressed, and purified, and both are functional [FeFe]-hydrogenases. Additionally, within the genome the HYDA1 and HYDA2 genes cluster with two putative genes which encode hydrogenase maturation proteins. This gene cluster resembles operon-like structures found within bacterial genomes and may provide further insight into evolutionary relationships between bacterial and algal [FeFe]-hydrogenase genes.

Light and the circadian clock mediate time-specific changes in sensitivity to UV-B stress under light/dark cycles.

In Arabidopsis, the circadian clock regulates UV-B-mediated changes in gene expression. Here it is shown that circadian clock components are able to inhibit UV-B-induced gene expression in a gene-by-gene-specific manner and act downstream of the initial UV-B sensing by COP1 (CONSTITUTIVE PHOTOMORPHOGENIC 1) and UVR8 (UV RESISTANCE LOCUS 8). For example, the UV-B induction of ELIP1 (EARLY LIGHT INDUCIBLE PROTEIN 1) and PRR9 (PSEUDO-RESPONSE REGULATOR 9) is directly regulated by LUX (LUX ARRYTHMO), ELF4 (EARLY FLOWERING 4), and ELF3. Moreover, time-dependent changes in plant sensitivity to UV-B damage were observed. Wild-type Arabidopsis plants, but not circadian clock mutants, were more sensitive to UV-B treatment during the night periods than during the light periods under diel cycles. Experiments performed under short cycles of 6h light and 6h darkness showed that the increased stress sensitivity of plants to UV-B in the dark only occurred during the subjective night and not during the subjective day in wild-type seedlings. In contrast, the stress sensitivity of Arabidopsis mutants with a compromised circadian clock was still influenced by the light condition during the subjective day. Taken together, the results show that the clock and light modulate plant sensitivity to UV-B stress at different times of the day.

Rcl1 protein, a novel nuclease for 18 S ribosomal RNA production.

In all forms of life, rRNAs for the small and large ribosomal subunit are co-transcribed as a single transcript. Although this ensures the equimolar production of rRNAs, it requires the endonucleolytic separation of pre-rRNAs to initiate rRNA production. In yeast, processing of the primary transcript encoding 18 S, 5.8 S, and 25 S rRNAs has been studied extensively. Nevertheless, most nucleases remain to be identified. Here, we show that Rcl1, conserved in all eukaryotes, cleaves pre-rRNA at so-called site A(2), a co-transcriptional cleavage step that separates rRNAs destined for the small and large subunit. Recombinant Rcl1 cleaves pre-rRNA mimics at site A(2) in a reaction that is sensitive to nearby RNA mutations that inhibit cleavage in vivo. Furthermore, mutations in Rcl1 disrupt rRNA processing at site A(2) in vivo and in vitro. Together, these results demonstrate that the role of Rcl1 in eukaryotic pre-rRNA processing is identical to that of RNase III in bacteria: to co-transcriptionally separate the pre-rRNAs destined for the small and large subunit. Furthermore, because Rcl1 has no homology to other known endonucleases, these data also establish a novel class of nucleases.

Who needs grief counseling? A report from the Scott & White Grief Study.

Cluster analysis was performed on a diverse group of 69 non-clinical grievers whose loved ones died between 12-40 months prior to the study. Based on psychometric measures of both bereavement distress and growth, three distinct clusters emerged: High Grief (high distress-low growth; n = 16); High Growth (low distress-high growth; n = 32); and Low Impact (low distress-low growth; n = 21). Discriminant function analyses showed that the High Grief cluster differed robustly from the other two groups on several measures of grief adaptation and coping; the differences between the High Growth and Low Impact clusters were less pronounced. High Grief participants sought grief counseling significantly more often whereas the Low Impact grievers preferred medicinal help for symptoms if they sought any professional assistance at all. When High Growth participants sought counseling, they seemed to focus on growth-oriented dimensions rather than mere symptom relief. Of the 11 participants who sought grief counseling for their loss, 10 (91%) found the experience to be helpful. Findings are discussed in the context of meta-analytic studies of the effectiveness of grief counseling.

Incorporating PDA use in diabetes self-care: a central Texas Primary Care Research Network (CenTexNet) study.

INTRODUCTION: We investigated the feasibility of incorporating the use of the personal digital assistant (PDA) in diabetes self-care in primary care. METHODS: Adults with type 2 diabetes whose last measured HbA1c value was 8.0% or greater were recruited from 4 family practice clinics. A trained research assistant provided one-on-one training on the use of a loaned PDA preinstalled with Diabetes Pilot software. RESULTS: Of 550 potential subjects invited for participation, only 98 (17.8%) called to schedule an orientation visit. However, 18 were never contacted when the recruitment goal was reached. Of the remaining 80 respondents, 43 (53.8%) met all study inclusion criteria. Participants' mean age was 55.2 years (SD = 10.1). The majority were female (62.8%) and white (62.8%), 83.7% had at least some college education, and most reported an income of $30,000 to $69,999. The mean baseline HbA1c was 10.0% (SD = 1.5). Major challenges of concern to the practicing family physician included few subjects agreeing to participate even though it was free, subjects who agreed to participate being generally different from those who decided not to participate, some PDAs not returned, and the relatively high cost of the intervention. CONCLUSIONS: Attempts to incorporate PDA use in diabetes self-care may be significantly challenging, although feasible. We identified several challenges and suggest strategies to overcome them.

Physician response to written feedback on a medication discrepancy found with their elderly ambulatory patients.

OBJECTIVES: To assess physicians' responses to written feedback on medication discrepancies found with their elderly ambulatory patients. DESIGN: Cross-sectional survey. SETTING: Four clinics of a large university-affiliated, multispecialty group practice associated with a 186,000-member health maintenance organization. PARTICIPANTS: Patients aged 65 and older (n=202) and their family physicians (n=32). MEASUREMENTS: Medication discrepancies and physicians' responses to written feedback on letters and adhesive labels containing a list of patients' actual medications. RESULTS: A medication discrepancy was identified with 171 of 202 patients (84.7%). They resulted from patients not taking charted medications (52.9%), patients taking medications that were not charted (34.3%), or difference in dosage and/or schedule (12.8%). The medications involved were mostly complementary/alternative (28.3%), respiratory/allergy (15.1%), and analgesics (14.1%). The majority of physicians reported that the letters (93.8%) and accompanying labels (90.6%) were helpful to them. Half of the physicians reported filing the letters in patients' charts, whereas the other half discarded them. The majority (93.8%) also perceived the labels as an additional benefit to their practice and placed them in patients' charts to be used to correct patients' medications. Receptivity to the feedback was unrelated to physician age group, sex, years in practice, or clinic of practice. CONCLUSION: Although medication discrepancies are common in elderly ambulatory patients, their family physicians appreciate assistance in correcting these discrepancies, although potential problems, such as cultural or organizational resistance to the open disclosure of medication discrepancies in medical records due to associated legal ramifications, may need to be resolved.

Parent-child concordance on reported barriers to helmet use by children.

BACKGROUND: We determined the agreement between parents and their school-age children on reported barriers to bicycle helmet use. MATERIAL/METHODS: We conducted a cross-sectional survey in a 2-county Central Texas region with no helmet use legislation. Parent-child pairs, selected through a randomized, multi-stage sampling procedure and pre-matched by unique identifiers, were surveyed independently with self-administered questionnaires. Parent-child concordance was assessed using Kappa statistic. RESULTS: Of 1,987 surveys distributed, children returned 1,203 (61%) while parents returned 636 (53% of child respondents). Parents included 31% college graduates and 33% reported annual income of >55,000 dollars. Children included 60% whites, 16% blacks, and 16% Hispanics. The most popular reasons cited by children as barriers to helmet use were not having one (34%), being a safe rider (31%), and helmets messing up hair (18%). Good concordance was found on reported child bicycle riding (parent=88.0% vs. child=88.0%; K=0.64) and child helmet use the last time child rode a bicycle (parent=25.1% vs. child=28.0%; K=0.54). While good concordance was also found for reported helmet ownership (parent=31.9% vs. child=29.9%; K= 0.50), poor concordance was found for other barriers to helmet use including helmets looking ugly (parent=6.5% vs. child=13.4%; K=0.38) and messing up hair (parent=5.6% vs. child=15.2%; K=0.36). CONCLUSIONS: Although parents may be generally aware of their children's bicycle riding and helmet use habits, they may not be fully aware of the reasons why their children may not use a helmet. Public education and interventions on helmet promotion need to focus on parents.

Helmet use: a survey of 4 common childhood leisure activities.

OBJECTIVE: To compare the distribution and observation of helmet use patterns among 4 common childhood leisure activities-bicycle riding, in-line skating, skateboarding, and scooter riding-in a setting with no helmet use legislation. DESIGN: A cross-sectional, unobtrusive, direct observation of children engaged in 1 of the 4 activities was conducted during an 8-week period. SETTING: Eight communities of at least 1000 persons each in a 2-county Central Texas area. MAIN OUTCOME MEASURES: Prevalence of activity, helmet use, and correct helmet use. RESULTS: Of 841 children observed, most rode bicycles (74.8%); only 4.2% rode skateboards. They included 127 children estimated to be younger than 6 years (15.1%) and 495 estimated to be aged between 6 and 12 years (58.9%). Most were male (67.3%) and observed in urban communities (61.7%). The locations of highest concentration of the 4 activities were minor streets for bicycle riding, playgrounds for in-line skating, and sidewalks for skateboarding and scooter riding. The rate of overall helmet use was 13.6% and did not vary significantly by activity: in-line skating, 18.2%; skateboarding, 14.3%; bicycle riding, 13.5%; and scooter riding, 11.5%. However, the observed correct helmet use prevalence of 72.6% differed significantly by activity. Most children riding scooters wore their helmets incorrectly. Helmet use was positively associated with helmet use by accompanying children and/or adults. CONCLUSIONS: While bicycle riding was the most popular activity observed, helmet use was most prevalent among in-line skaters and least prevalent among scooter riders, many of whom also wore them incorrectly. Observed helmet use was influenced mostly by adult and peer helmet use, indicating that public education and interventions should target children and their parents as well as scooter riders.