Improved branching ratio measurement for the decay K(0)(L) --> &mgr;(+)&mgr;(-)

We report results from Experiment 871, performed at the BNL AGS, of a measurement of the branching ratio K(0)(L)-->&mgr;(+)&mgr;(-) with respect to the CP-violating mode K(0)(L)-->pi(+)pi(-). This experiment detected over 6200 candidate &mgr;(+)&mgr;(-) events, a factor of 6 more than that seen in all previous measurements combined. The resulting branching ratio gamma(K(0)(L)-->&mgr;(+)&mgr;(-))/gamma(K(0)(L)-->pi(+)pi(-)) = (3. 474+/-0.057)x10(-6) leads to a branching fraction B(K(0)(L)-->&mgr;(+)&mgr;(-)) = (7.18+/-0.17)x10(-9), which is consistent with the current world average, and reduces the uncertainty in this decay mode by a factor of 3.

Total plasma clearance of 51Cr-EDTA: variation with age and sex in normal adults

Although inulin clearance measured during constant infusion is still considered the reference method, single-injection of 51Cr-EDTA with subsequent plasma sampling has become the most popular technique for the routine assessment of glomerular filtration rate. Despite the fact that the technique has been in use for 30 years, there are only a few reports of normal values calculated directly from 51Cr-EDTA data and normal ranges have generally been produced by conversions of inulin data. The aim of this study was to measure the variation in total plasma clearance, calculated directly from 51Cr-EDTA measurements, in normal males and females, of Saudi Arabian origin, over a wide range. Altogether, 201 potential kidney donors aged 16-60 years were studied. No statistically significant association of total plasma clearance with age or sex could be demonstrated; however, predictive equations suggesting a small decline in total plasma clearance with age were developed. The figures presented suggest that the reduction in total plasma clearance of 51Cr-EDTA with age is relatively shallow up to the age of at least 60 years and that normal ranges produced by conversion of inulin data may overestimate the decline with age.

Severe bronchopulmonary dysplasia increases risk for later neurological and motor sequelae in preterm survivors

Preterm children who develop severe chronic lung disease may be developmentally compromised by exposure to hypoxic episodes. This study aims to determine if children with severe bronchopulmonary dysplasia (BPD) who required home oxygen therapy were at greater risk for neurological and motor deficits at school age than preterm peers without BPD. This study evaluated 27 subjects with BPD and 27 preterm control infants matched for gestational age, birthweight, sex, and year of birth at a mean age of 9.9 years (2.0 SD) using standardized neuromotor outcome measures. Pair-matched comparisons and regression analyses were used to determine if subjects with BPD were at increased risk for neuromotor sequelae. Neurological abnormalities, including subtle neurological signs, cerebral palsy, microcephaly, and behavioral difficulties were highly prevalent in the BPD group (71% compared with 19% in control group, P<0.005). Over half the BPD cohort had difficulties in gross and/or fine motor skills. There were significant differences in postural stability between groups. Duration of hospitalization and home oxygen treatment, and decreased lung function at school age, markers of severity of illness, correlated with motor outcomes. The findings underline the importance of preventing the cardiorespiratory complications associated with chronic lung disease to minimize disability in preterm children. For children with severe BPD, better recognition and subsequent remediation of neuromotor impairments that manifest at school age may help maximize their functional potential.

The HAND1 basic helix-loop-helix transcription factor regulates trophoblast differentiation via multiple mechanisms

The basic helix-loop-helix (bHLH) transcription factor genes Hand1 and Mash2 are essential for placental development in mice. Hand1 promotes differentiation of trophoblast giant cells, whereas Mash2 is required for the maintenance of giant cell precursors, and its overexpression prevents giant cell differentiation. We found that Hand1 expression and Mash2 expression overlap in the ectoplacental cone and spongiotrophoblast, layers of the placenta that contain the giant cell precursors, indicating that the antagonistic activities of Hand1 and Mash2 must be coordinated. MASH2 and HAND1 both heterodimerize with E factors, bHLH proteins that are the DNA-binding partners for most class B bHLH factors and which are also expressed in the ectoplacental cone and spongiotrophoblast. In vitro, HAND1 could antagonize MASH2 function by competing for E-factor binding. However, the Hand1 mutant phenotype cannot be solely explained by ectopic activity of MASH2, as the Hand1 mutant phenotype was not altered by further mutation of Mash2. Interestingly, expression of E-factor genes (ITF2 and ALF1) was down-regulated in the trophoblast lineage prior to giant cell differentiation. Therefore, suppression of MASH2 function, required to allow giant cell differentiation, may occur in vivo by loss of its E-factor partner due to loss of its expression and/or competition from HAND1. In giant cells, where E-factor expression was not detected, HAND1 presumably associates with a different bHLH partner. This may account for the distinct functions of HAND1 in giant cells and their precursors. We conclude that development of the trophoblast lineage is regulated by the interacting functions of HAND1, MASH2, and their cofactors.

Treatment of lesions of osteomyelitis in the hind flippers of six grey seals (Halichoerus grypus)

Six rescued grey seal (Halichoerus grypus) pups had traumatic injuries to their hind flippers; three had osteomyelitis without fractures, one had a single fracture and associated osteomyelitis, and two had multiple compound fractures and large open wounds. The medical and surgical methods used to treat these lesions are described. A proprietary waterproof covering appeared to be a better method for dressing the wounds than conventional bandaging.

Deletion of the Cul1 gene in mice causes arrest in early embryogenesis and accumulation of cyclin E

The stability of many proteins is controlled by the ubiquitin proteolytic system, which recognizes specific substrates through the action of E3 ubiquitin ligases [1]. The SCFs are a recently described class of ubiquitin ligase that target a number of cell cycle regulators and other proteins for degradation in both yeast and mammalian cells [2] [3] [4] [5] [6]. Each SCF complex is composed of the core protein subunits Skp1, Rbx1 and Cul1 (known as Cdc53 in yeast), and substrate-specific adaptor subunits called F-box proteins [2] [3] [4]. To understand the physiological role of SCF complexes in mammalian cells, we generated mice carrying a deletion in the Cul1 gene. Cul1(-/-) embryos arrested around embryonic day 6.5 (E6.5) before the onset of gastrulation. In all cells of the mutant embryos, cyclin E protein, but not mRNA, was highly elevated. Outgrowths of Cul1(-/-) blastocysts had limited proliferative capacity in vitro and accumulated cyclin E in all cells. Within Cul1(-/-) blastocyst cultures, trophoblast giant cells continued to endocycle despite the elevated cyclin E levels. These results suggest that cyclin E abundance is controlled by SCF activity, possibly through SCF-dependent degradation of cyclin E.

Reproducibility of thoracic aortic diameter measurement using computed tomographic scans

OBJECTIVES

Decisions to recommend elective surgical repair of thoracic aortic aneurysms (TAA) may be based on size or expansion rate, which are used as indices of the risk of rupture. Measurement error may thus affect clinical decision-making. In order to evaluate the reproducibility of aortic diameter measurements of TAA, we assessed departmental inter- and intra-observer variability of measurement of pre-selected computed tomographic scan images of aneurysmal segments of the thoracic aorta.

METHODS

We compared measurements of minimum aortic diameter made by four observers in 50 pre-selected scans and at different times by two observers using a calliper method and a measurement tool within the scan. Differences in measured dimension were analysed using Wilcoxon's signed ranks test and the repeatability assessed using the method of Bland and Altman.

RESULTS

There were no significant inter-observer differences among three observers but there were significant differences between another observer and two other observers (P < 0.05). No significant intra-observer differences existed. The best intra-observer repeatability was 2.25 while the worst inter-observer repeatability was 4.37. The mean and maximum difference in measurement were +/-0.88 mm and +/-8.0 mm, respectively. Variability of measurement increased with aortic diameter.

CONCLUSIONS

Calliper measurement of TAA is an acceptable measurement method for surveillance of TAA but appears most accurate with a single observer. Increasing error is seen with increasing diameter which may compound error in estimation of expansion rate. Standardisation of technique is advisable for multiple observers and aortic units should adopt quality assurance protocols to minimise error.

The neonatal presentation of Prader-Willi syndrome revisited

We describe 6 newborns evaluated for hypotonia, later diagnosed with Prader-Willi syndrome despite the absence of the classical neonatal features of this syndrome. Specific genetic testing for Prader-Willi syndrome should be considered for all neonates with undiagnosed central hypotonia even in the absence of the other major features of this syndrome.

The association of asymptomatic bacterial vaginosis with upper genital tract infection

Objective: To determine whether asymptomatic bacterial vaginosis (BV) is associated with upper genital tract inflammation or bacterial colonization.Methods: Fifty nonpregnant women with intact uteri who planned to undergo gynecologic surgery and had no recent symptoms of vaginal infection were enrolled. We obtained a vaginal swab for Gram stain, endocervical swab for chlamydia and gonorrhea DNA probe testing, and Pipelle endometrial biopsy for aerobic and anaerobic cultures and histology. We correlated surgical findings and histology of available surgical specimens with the microbiologic results. The diagnosis of BV was made according to Speigel's criteria. Bacteria isolated from the uterus were classified as high virulence versus low virulence. Contingency tables were analyzed using the chi-square or Fisher Exact tests.Results: Twenty-one of 50 patients had BV on Gram stain, 3 had intermediate BV, and 3 had unreadable slides. Eleven patients had histologic endometritis, including 7 of the 21 with BV. The association between BV and endometritis was not statistically significant. Thirty-eight patients had a positive endometrial culture; 18 of these also had BV and 3 had intermediate BV. Of patients with a positive endometrial culture, isolates from those who also had BV or intermediate BV were more likely to be highly virulent pathogens compared to those who tested negative for BV (P <.05). No patients had positive gonorrhea or chlamydia tests. Of the 37 patients who underwent abdominal surgery, 20 had visible adhesions. The association between adhesions and endometritis, BV, or positive endometrial cultures was not significant.Conclusion: Patients with asymptomatic BV are more likely than patients without BV to have highly virulent bacteria isolated from the endometrium. BV may predispose to upper genital tract infection.

Demonstration projects in community-based prevention

Community-based demonstration projects represent the translation of research findings into practice. This article discusses the scientific basis for demonstration projects and illustrates various principles through two large-scale programs: the Health Promotion and Disease Prevention Research Centers and the Community-Based Public Health initiative. These programs have shown several key components for success, including: building effective partnerships, using existing data effectively, adopting a causal model in intervention design, employing appropriate evaluation techniques, using policy change as an intervention, and utilizing the potential of community groups to foster change among professional partners.

The Hand1 bHLH transcription factor is essential for placentation and cardiac morphogenesis

The placenta and cardiovascular system are the first organ systems to form during mammalian embryogenesis. We show here that a single gene is critical for development of both. The Hand1 gene, previously called Hxt, eHAND and Thing1, encodes a basic helix-loop-helix (bHLH) transcription factor that starts to be expressed during pre-implantation development. After implantation, Hand1 expression is restricted to placental trophoblast cells and later to embryonic cardiac and neural crest cells. We generated Hand1-null mutant mice by gene targetting. Homozygous mutant embryos arrested by embryonic day (E) 7.5 of gestation with defects in trophoblast giant cell differentiation. This early mortality could be rescued by aggregation of mutant embryos with wild-type tetraploid embryos, which contribute wild-type cells to the trophoblast, but not the embryo. By E10.5, however, the Hand1-null fetuses derived from tetraploid chimaeras died due to cardiac failure. Their heart tubes showed abnormal looping and ventricular myocardial differentiation. Therefore, Hand1 is essential for differentiation of both trophoblast and cardiomyocytes, which are embryologically distinct cell lineages.

Enhancement of aminolevulinic acid based photodynamic therapy by adriamycin

This paper reports on studies that evaluate the interaction between delta-aminolevulinic acid (ALA)-based photodynamic therapy (PDT) and adriamycin (ADM) in an animal model system. Two groups of mice bearing a transplantable mammary adenocarcinoma received ADM i.p. in a single dose of 5 mg (low dose) and 30 mg (high dose) per kg body weight. Sixteen or 40 h after administration of the drug, mice were sacrificed, tumours, livers and hearts were removed and porphyrins, enzyme activities and malondialdehyde content were determined. Tumour explants of ADM-treated mice were incubated with ALA and irradiated with an He-Ne laser. Re-implantation of these in vitro PDT-treated explants into test animals showed that inhibition of tumour growth was significantly enhanced by combined treatment when the low dose of ADM was used. There were no significant changes in porphyrin content, ALA dehydratase and porphobilinogenase activities in the tissues analyzed after ADM treatment as compared with control values. ADM toxicity is thought to be related to semiquinone free radical formation with subsequent generation of reactive oxygen species such as peroxide and hydroxyl radical. These species are considered to initiate lipid peroxidation (LPO) and cause DNA damage. In the case of low-dose treatment with ADM a significant increase in the LPO product, malondialdehyde, was observed after PDT whereas with the high-dose regimen no changes were observed. In the case of explants of (non-irradiated) cardiac tissue malondialdehyde production was also found to be dependent on the dose and time of administration of adriamycin. In our in vivo/in vitro model system we have shown that pre-treatment with ADM increased the cytotoxicity of ALA-PDT at a dosage level of ADM which did not raise LPO levels in heart tissue. The mechanism of this effect has not been clearly elucidated but our data suggest that the observed enhancement of PDT may be attributed in part to the weakening of cellular defence mechanisms by the pre-treatment involving free radical generation by ADM.

Beyond law and ethics: an interdisciplinary course in family law and family therapy

The professions of family therapy and law share many clients and areas of overlap. Law-related coursework in family therapy programs is typically limited to legal, ethical, and professional issues. However, students can also benefit from understanding other areas of overlap, such as divorce, child custody, and mediation. This article discusses the curriculum for an interdisciplinary course that educates both family therapy and law students. The course provides: (1) a substantive education about similarities and differences between the professions, how they operate as systems, and specific areas of overlap, (2) opportunities to learn clinical skills, and (3) opportunities for personal insight about skills, personality types, and negotiation styles, and how these may differ between the professions.

Stimulation of tetrapyrrole synthesis in mammalian epithelial cells in culture by exposure to aminolaevulinic acid

Tetrapyrrole synthesis in CNCM-1221 cells exposed to 0.6 mM aminolaevulinic acid (ALA) was found to be approximately linear over a 6-h period of incubation. The rate was not significantly affected by cell density over a range of 0.015 to 0.15 x 10(6) cells cm(-2) (final cell density). Tetrapyrrole synthesis was not affected by GABA or glutamic acid in concentrations up to 6 mM and 2.72 mM respectively, suggesting that these amino acids, which are similar in structure to ALA, do not competitively inhibit the ALA uptake pathway in these cells. Pre-exposure to haem arginate (up to 100 microM) was inhibitory, presumably by suppression (through the inhibition of ALA synthase) of an endogenous component of the response. The ALA-stimulated response was not modified by co-exposure to AIA (up to 100 mg ml(-1)). Despite significant reduction of protein synthesis, the porphyrinogenic response of cells exposed to ALA was unaffected by cycloheximide (10 microg ml(-1)) or actinomycin D (10 microg ml(-1)) even when cells were preincubated with these agents for 3 h before ALA exposure. Fetal bovine serum (10%) inhibited tetrapyrrole synthesis by 30% but increased the rate of porphyrin export by cells by a factor of 1.5. The uptake of [14C]ALA was shown to be strongly influenced by the density of the cultures. In dense cultures (final cell density of approximately 0.15 x 10(6) cells cm(-2)), the ALA uptake rate was less than 0.8 compared with a maximum rate of 4.2 fmol per cell h(-1) at a cell density of 0.02 x 10(6) cells cm(-2). Since tetrapyrrole synthesis is less affected than ALA uptake by cell density, the resultant discrepancy in ALA incorporation occurring in dense cultures implies that endogenous ALA synthesis is induced in these cells. ALA uptake was not affected by cycloheximide or actinomycin D in serum-free conditions. However, fetal bovine serum decreased external ALA uptake by about 50%. This effect was abrogated by preincubation with cycloheximide.

Is admission chest radiography of any clinical value in acute stroke patients?

Chest radiographs are frequently requested on admission of patients with a clinical diagnosis of acute stroke. This study assesses their value in subsequent management of these patients. A retrospective analysis of 435 patients with a clinical diagnosis of acute stroke was made. All admission chest radiographs were reviewed to document both radiographic quality and any radiological abnormality. In those patients with an abnormal radiograph, clinical records were reviewed to assess their impact on clinical management. Eighty-six percent of patients had a chest radiograph performed on admission. 77.5% of these films were deemed to be technically unsatisfactory, the commonest problems being positioning and suboptimal inspiration. Radiological abnormality was demonstrated in 61 patients (16.4% of radiographs obtained). Clinical management was altered in 14 of the 61 patients (3.8% of the total number of patients radiographed). Radiological abnormality was missed by the admitting clinicians in four radiographs (1 hilar mass, 2 cases of consolidation, one of pulmonary oedema). One abnormality not clinically suspected was recorded (multiple metastases). We conclude that admission chest radiographs in patients with an acute stroke are not indicated in the absence of appropriate clinical indications.

Gender differences in perceptions of household labor

The perceptions of household labor contributions of 277 individuals were examined. At the time of the study, participants were married or cohabiting, although no couples participated. The relationship between perceptions of contributions to household labor and the independent variables of gender ideology, a wife's relative contribution to family income, a husband's time availability, and family demographic variables were studied. Responses of people in dual-earner arrangements were compared with responses of people in households in which the woman was a full-time homemaker. In dual-earner families, the woman's relative contribution to family income and number of children were negatively associated with perceptions of her contributions to household tasks relative to those of her partner. In both dual-earner arrangements and situations in which the wife was a full-time homemaker, a statistically significant association was found between the perceived division of household labor and gender. Women were more likely than men to report that a women contributes significantly more to housework than the man. Men in dual-earner relationships reported the smallest contribution to household labor by women.

Student Perceptions of Changing Answers on Multiple Choice Examinations

The belief that changing answers on examinations is detrimental persists in spite of empirical research which does not support that belief. While the research in education has consistently shown that changing answers is beneficial, few studies have been done on the behavior and psychological process of changing answers. This qualitative study found that students prefer not to change answers and do not believe it is advantageous to do so. Most students took tests in such a manner that at least a portion of the questions were re-read. Reasons given for changing answers included reconsidering the answers after re-reading the question, mismarking the answer sheet, re-guessing, and receiving a clue later in the test. The students who changed answers often found they had misread the questions initially when they re-read it. Re-reading the question was most likely to result in a change from wrong to right. Re-guessing was not found to be as beneficial to the student scores.