Catechol-O-methyltransferase-deficient mice exhibit sexually dimorphic changes in catecholamine levels and behavior

Catechol-O-methyltransferase (COMT) is one of the major mammalian enzymes involved in the metabolic degradation of catecholamines and is considered a candidate for several psychiatric disorders and symptoms, including the psychopathology associated with the 22q11 microdeletion syndrome. By means of homologous recombination in embryonic stem cells, a strain of mice in which the gene encoding the COMT enzyme has been disrupted was produced. The basal concentrations of brain catecholamines were measured in the striatum, frontal cortex, and hypothalamus of adult male and female mutants. Locomotor activity, anxiety-like behaviors, sensorimotor gating, and aggressive behavior also were analyzed. Mutant mice demonstrated sexually dimorphic and region-specific changes of dopamine levels, notably in the frontal cortex. In addition, homozygous COMT-deficient female (but not male) mice displayed impairment in emotional reactivity in the dark/light exploratory model of anxiety. Furthermore, heterozygous COMT-deficient male mice exhibited increased aggressive behavior. Our results provide conclusive evidence for an important sex- and region-specific contribution of COMT in the maintenance of steady-state levels of catecholamines in the brain and suggest a role for COMT in some aspects of emotional and social behavior in mice.

Compulsory averaging of crowded orientation signals in human vision

A shape can be more difficult to identify when other shapes are near it. For example, when several grating patches are viewed parafoveally, observers are unable to report the orientation of the central patch. This phenomenon, known as 'crowding,' has historically been confused with lateral masking, in which one stimulus attenuates signals generated by another stimulus. Here we show that despite their inability to report the orientation of an individual patch, observers can reliably estimate the average orientation, demonstrating that the local orientation signals are combined rather than lost. Our results imply that crowding is distinct from ordinary masking, and is perhaps related to texture perception. Under crowded conditions, the orientation signals in primary visual cortex are pooled before they reach consciousness.

Letrozole, a new oral aromatase inhibitor for advanced breast cancer: double-blind randomized trial showing a dose effect and improved efficacy and tolerability compared with megestrol acetate

PURPOSE

To compare two doses of letrozole and megestrol acetate (MA) as second-line therapy in postmenopausal women with advanced breast cancer previously treated with antiestrogens.

PATIENTS AND METHODS

Five hundred fifty-one patients with locally advanced, locoregionally recurrent or metastatic breast cancer were randomly assigned to receive letrozole 2.5 mg (n = 174), letrozole 0.5 mg (n = 188), or MA 160 mg (n = 189) once daily in a double-blind, multicenter trial. Data were analyzed for tumor response and safety variables up to 33 months of follow-up evaluation and for survival up to 45 months.

RESULTS

Letrozole 2.5 mg produced a significantly higher overall objective response rate (24%) compared with MA (16%; logistic regression, P = .04) or letrozole 0.5 mg (13%; P = .004). Duration of objective response was significantly longer for letrozole 2.5 mg compared with MA (Cox regression, P = .02). Letrozole 2.5 mg was significantly superior to MA and letrozole 0.5 mg in time to treatment failure (P = .04 and P = .002, respectively). For time to progression, letrozole 2.5 mg was superior to letrozole 0.5 mg (P = .02), but not to MA (P = .07). There was a significant dose effect in overall survival in favor of letrozole 2.5 mg (P = .03) compared with letrozole 0.5 mg. Letrozole was significantly better tolerated than MA with respect to serious adverse experiences, discontinuation due to poor tolerability, cardiovascular side effects, and weight gain.

CONCLUSION

The data show letrozole 2.5 mg once daily to be more effective and better tolerated than MA in the treatment of postmenopausal women with advanced breast cancer previously treated with antiestrogens.

Myocardial ischaemia during daily life in patients with stable angina: its relation to symptoms and heart rate changes

In thirty patients with stable angina and positive exercise tests, ambulatory ST segment monitoring was used to record episodes of transient myocardial ischaemia during daily life. All patients had four consecutive days of monitoring and in 20 patients long-term variability was assessed by repeated 48 hour monitoring and exercise testing over 18 months. There were 1934 episodes of rectilinear or downsloping ST-depression (911, 1 mm; 638, 2 mm; 385, greater than 3 mm) in 446 days of recording, of which only 470 (24%) were accompanied by angina. Positron tomography showed evidence of regional myocardial ischaemia during both symptomatic and asymptomatic ST depression. On average, heart rate at the onset of both symptomatic and asymptomatic ST episodes was significantly lower than the rate at the onset of ST depression during exercise testing (98 +/- 20.5 vs 124 +/- 17 beats/minute). Heart rate rose by more than 10 beats in the minute preceding ST depression in only 23% of episodes. Over 18 months, 8 (40%) patients exhibited marked variability in the number of daily ST episodes. Variability of ST depression was consistently underestimated by symptoms and not reflected by exercise testing. Thus, patients with stable angina showed frequent, variable, and often asymptomatic electrocardiographic evidence of ischaemia. Heart rate increase was not common before myocardial ischaemia, suggesting that, in such patients, transient impairment in coronary supply may be at least as important as excessive increase in demand in the genesis of ischaemia during daily life.

Biodegradable block copolymers for delivery of proteins and water-insoluble drugs

Release of several drugs from new ABA-type biodegradable thermal gels, ReGel, including proteins and conventional molecules, are presented. These are biodegradable, biocompatible polymers that demonstrate reverse thermal gelation properties. Organic solvents are not used in the synthesis, purification, or formulation of these polymers. The unique characteristics of ReGel hinge on the following two key properties: (1) ReGel is a water soluble, biodegradable polymer at temperatures below the gel transition temperature; (2) ReGel forms a water-insoluble gel once injected. This is consistent with a hydrophobically bonded gel state where all interactions are physical, with no covalent crosslinking. An increase in viscosity of approximately 4 orders of magnitude accompanies the sol--gel transition. The gel forms a controlled release drug depot with delivery times ranging from 1 to 6 weeks. ReGel's inherent ability to solubilize (400 to >2000-fold) and stabilize poorly soluble and sensitive drugs, including proteins is a substantial benefit. The gel provided excellent control of the release of paclitaxel for approximately 50 days. Direct intratumoral injection of ReGel/paclitaxel (OncoGel) results in a slow clearance of paclitaxel from the injection site with minimal distribution into any organ. Efficacies equivalent to maximum tolerated systemic dosing were observed at OncoGel doses that were 10-fold lower. Data on protein release (pGH, G-CSF, insulin, rHbsAg) and polymer biocompatibility are discussed.

Targeting the RNA m6A Reader YTHDF2 Selectively Compromises Cancer Stem Cells in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is an aggressive clonal disorder of hematopoietic stem cells (HSCs) and primitive progenitors that blocks their myeloid differentiation, generating self-renewing leukemic stem cells (LSCs). Here, we show that the mRNA m6A reader YTHDF2 is overexpressed in a broad spectrum of human AML and is required for disease initiation as well as propagation in mouse and human AML. YTHDF2 decreases the half-life of diverse m6A transcripts that contribute to the overall integrity of LSC function, including the tumor necrosis factor receptor Tnfrsf2, whose upregulation in Ythdf2-deficient LSCs primes cells for apoptosis. Intriguingly, YTHDF2 is not essential for normal HSC function, with YTHDF2 deficiency actually enhancing HSC activity. Thus, we identify YTHDF2 as a unique therapeutic target whose inhibition selectively targets LSCs while promoting HSC expansion.

Evaluating meta-ethnography: systematic analysis and synthesis of qualitative research

BACKGROUND

Methods for reviewing and synthesising findings from quantitative research studies in health care are well established. Although there is recognition of the need for qualitative research to be brought into the evidence base, there is no consensus about how this should be done and the methods for synthesising qualitative research are at a relatively early stage of development.

OBJECTIVE

To evaluate meta-ethnography as a method for synthesising qualitative research studies in health and health care.

METHODS

Two full syntheses of qualitative research studies were conducted between April 2002 and September 2004 using meta-ethnography: (1) studies of medicine-taking and (2) studies exploring patients' experiences of living with rheumatoid arthritis. Potentially relevant studies identified in multiple literature searches conducted in July and August 2002 (electronically and by hand) were appraised using a modified version of the Critical Appraisal Skills Programme questions for understanding qualitative research. Candidate papers were excluded on grounds of lack of relevance to the aims of the synthesis or because the work failed to employ qualitative methods of data collection and analysis.

RESULTS

Thirty-eight studies were entered into the medicine-taking synthesis, one of which did not contribute to the final synthesis. The synthesis revealed a general caution about taking medicine, and that the practice of lay testing of medicines was widespread. People were found to take their medicine passively or actively or to reject it outright. Some, in particular clinical areas, were coerced into taking it. Those who actively accepted their medicine often modified the regimen prescribed by a doctor, without the doctor's knowledge. The synthesis concluded that people often do not take their medicines as prescribed because of concern about the medicines themselves. 'Resistance' emerged from the synthesis as a concept that best encapsulated the lay response to prescribed medicines. It was suggested that a policy focus should be on the problems associated with the medicines themselves and on evaluating the effectiveness of alternative treatments that some people use in preference to prescribed medicines. The synthesis of studies of lay experiences of living with rheumatoid arthritis began with 29 papers. Four could not be synthesised, leaving 25 papers (describing 22 studies) contributing to the final synthesis. Most of the papers were concerned with the everyday experience of living with rheumatoid arthritis. This synthesis did not produce significant new insights, probably because the early papers in the area were substantial and theoretically rich, and later papers were mostly confirmatory. In both topic areas, only a minority of the studies included in the syntheses were found to have referenced each other, suggesting that unnecessary replication had occurred.

LIMITATIONS

We only evaluated meta-ethnography as a method for synthesising qualitative research, but there are other methods being employed. Further research is required to investigate how different methods of qualitative synthesis influence the outcome of the synthesis.

CONCLUSIONS

Meta-ethnography is an effective method for synthesising qualitative research. The process of reciprocally translating the findings from each individual study into those from all the other studies in the synthesis, if applied rigorously, ensures that qualitative data can be combined. Following this essential process, the synthesis can then be expressed as a 'line of argument' that can be presented as text and in summary tables and diagrams or models. Meta-ethnography can produce significant new insights, but not all meta-ethnographic syntheses do so. Instead, some will identify fields in which saturation has been reached and in which no theoretical development has taken place for some time. Both outcomes are helpful in either moving research forward or avoiding wasted resources. Meta-ethnography is a highly interpretative method requiring considerable immersion in the individual studies to achieve a synthesis. It places substantial demands upon the synthesiser and requires a high degree of qualitative research skill. Meta-ethnography has great potential as a method of synthesis in qualitative health technology assessment but it is still evolving and cannot, at present, be regarded as a standardised approach capable of application in a routinised way.

FUNDING

Funding for this study was provided by the Health Technology Assessment programme of the National Institute for Health Research.

Sustained secretion of human alpha-1-antitrypsin from murine muscle transduced with adeno-associated virus vectors

Recombinant adeno-associated virus (AAV) vectors have been used to transduce murine skeletal muscle as a platform for secretion of therapeutic proteins. The utility of this approach for treating alpha-1-antitrypsin (AAT) deficiency was tested in murine myocytes in vitro and in vivo. AAV vectors expressing the human AAT gene from either the cytomegalovirus (CMV) promoter (AAV-C-AT) or the human elongation factor 1-alpha promoter (AAV-E-AT) were examined. In vitro in C2C12 murine myoblasts, the expression levels in transient transfections were similar between the two vectors. One month after transduction, however, the human elongation factor 1 promoter mediated 10-fold higher stable human AAT expression than the CMV promoter. In vivo transduction was performed by injecting doses of up to 1.4 x 10(13) particles into skeletal muscles of several mouse strains (C57BL/6, BALB/c, and SCID). In vivo, the CMV vector mediated higher levels of expression, with sustained serum levels over 800 micrograms/ml in SCID and over 400 micrograms/ml in C57BL/6 mice. These serum concentrations are 100,000-fold higher than those previously observed with AAV vectors in muscle and are at levels which would be therapeutic if achieved in humans. High level expression was delayed for several weeks but was sustained for over 15 wk. Immune responses were dependent upon the mouse strain and the vector dosage. These data suggest that recombinant AAV vector transduction of skeletal muscle could provide a means for replacing AAT or other essential serum proteins but that immune responses may be elicited under certain conditions.

Reovirus messenger RNA contains a methylated, blocked 5'-terminal structure: m-7G(5')ppp(5')G-MpCp-

Reovirus mRNA synthesized in vitro by the virus-associated RNA polymerase in the presence of S-adenosylmethionine contains blocked, methylated 5'-termini with the structure, m-7G(5')ppp(5')G-MpCp. The functional significance and possible mechanism of formation of this novel 5'-5' terminal nucleotide linkage are discussed.

Phase III, multicenter, double-blind, randomized study of letrozole, an aromatase inhibitor, for advanced breast cancer versus megestrol acetate

PURPOSE

To compare two doses of letrozole (0.5 mg and 2.5 mg every day) and megestrol acetate (40 mg qid) as endocrine therapy in postmenopausal women with advanced breast cancer previously treated with antiestrogens.

PATIENTS AND METHODS

This double-blind, randomized, multicenter, multinational study enrolled 602 patients, all of whom were included in the primary analysis in the protocol. Patients had advanced or metastatic breast cancer with evidence of disease progression while receiving continuous adjuvant antiestrogen therapy, had experienced relapse within 12 months of stopping adjuvant antiestrogen therapy given for at least 6 months, or had experienced disease progression while receiving antiestrogen therapy for advanced disease. Tumors were required to be estrogen receptor- and/or progesterone receptor-positive or of unknown status. Confirmed objective response rate was the primary efficacy variable. Karnofsky Performance Status and European Organization for Research and Treatment of Cancer quality-of-life assessments were collected for 1 year.

RESULTS

There were no statistically significant differences among the three treatment groups for overall objective tumor response. Patients treated with letrozole 0.5 mg had improvements in disease progression (P =.044) and a decreased risk of treatment failure (P =.018), compared with patients treated with megestrol acetate. Letrozole 0.5 mg showed a trend (P =.053) for survival benefit when compared with megestrol acetate. Megestrol acetate was more likely to produce weight gain, dyspnea, and vaginal bleeding, and the letrozole groups were more likely to experience headache, hair thinning, and diarrhea.

CONCLUSION

Given a favorable tolerability profile, once-daily dosing, and evidence of clinically relevant benefit, letrozole is equivalent to megestrol acetate and should be considered for use as an alternative treatment of advanced breast cancer in postmenopausal women after treatment failure with antiestrogens.

Prospective study of liver dysfunction in pregnancy in Southwest Wales

BACKGROUND

Liver dysfunction in pregnancy has serious consequences. Its frequency and characteristics have not been systematically documented in Britain. We have prospectively determined incidence, causes, and outcome of liver dysfunction in pregnancy in an obstetric unit in Southwest Wales, UK.

METHODS

A central laboratory identified all abnormal liver tests (bilirubin >25 micro mol/l, aspartate transaminase >40 U/l, or gamma glutamyl transpeptidase >35 U/l) from patients in antenatal clinics and wards of an obstetric unit serving a population of 250 000. Patients with abnormal liver tests were assessed and followed throughout and after pregnancy [corrected]. Medical advice was provided to obstetric teams.

FINDINGS

There were 4377 deliveries during the 15 month study. A total of 142 patients had abnormal liver tests. There were 206 contributing diagnoses, the great majority being pregnancy specific. Among the most important were pre-eclampsia (68), HELLP (haemolysis, elevated liver enzymes, low platelets) syndrome (30), obstetric cholestasis (23), hyperemesis gravidarum (11), acute fatty liver of pregnancy (five), and hepatic infarct (one). Sepsis, postoperative factors, and placental pathology (51) were not uncommonly responsible but incidental or pre-existing hepatobiliary disease was infrequent (17). Sixty five patients were delivered early by induction or caesarean section because of liver dysfunction. Despite substantial liver related morbidity, there were no maternal deaths and only two intrauterine deaths.

CONCLUSIONS

Liver dysfunction was seen in 3% of deliveries during a 15 month prospective study and was usually directly related to pregnancy with spontaneous recovery in the puerperium. Incidence of the most serious conditions, acute fatty liver of pregnancy and HELLP syndrome, was much greater than previously reported. Profound effects on maternal and infant health were observed but close medical and obstetric collaboration ensured low mortality.

Prediction of Staphylococcus aureus antimicrobial resistance by whole-genome sequencing

Whole-genome sequencing (WGS) could potentially provide a single platform for extracting all the information required to predict an organism's phenotype. However, its ability to provide accurate predictions has not yet been demonstrated in large independent studies of specific organisms. In this study, we aimed to develop a genotypic prediction method for antimicrobial susceptibilities. The whole genomes of 501 unrelated Staphylococcus aureus isolates were sequenced, and the assembled genomes were interrogated using BLASTn for a panel of known resistance determinants (chromosomal mutations and genes carried on plasmids). Results were compared with phenotypic susceptibility testing for 12 commonly used antimicrobial agents (penicillin, methicillin, erythromycin, clindamycin, tetracycline, ciprofloxacin, vancomycin, trimethoprim, gentamicin, fusidic acid, rifampin, and mupirocin) performed by the routine clinical laboratory. We investigated discrepancies by repeat susceptibility testing and manual inspection of the sequences and used this information to optimize the resistance determinant panel and BLASTn algorithm. We then tested performance of the optimized tool in an independent validation set of 491 unrelated isolates, with phenotypic results obtained in duplicate by automated broth dilution (BD Phoenix) and disc diffusion. In the validation set, the overall sensitivity and specificity of the genomic prediction method were 0.97 (95% confidence interval [95% CI], 0.95 to 0.98) and 0.99 (95% CI, 0.99 to 1), respectively, compared to standard susceptibility testing methods. The very major error rate was 0.5%, and the major error rate was 0.7%. WGS was as sensitive and specific as routine antimicrobial susceptibility testing methods. WGS is a promising alternative to culture methods for resistance prediction in S. aureus and ultimately other major bacterial pathogens.

Factors related to inflammation of the ovarian epithelium and risk of ovarian cancer

Previous epidemiologic observations consistently suggest that suppression of ovulation, tubal ligation, and hysterectomy reduce the risk of ovarian cancer and that perineal talc use increases the risk. We examined these and other risk factors in the context of a new hypothesis: that inflammation may play a role in ovarian cancer risk. Ovulation entails ovarian epithelial inflammation; talc, endometriosis, cysts, and hyperthyroidism may be associated with inflammatory responses of the ovarian epithelium; gynecologic surgery may preclude irritants from reaching the ovaries via ascension from the lower genital tract. We evaluated these risk factors in a population-based case-control study. Cases 20-69 years of age with a recent diagnosis of epithelial ovarian cancer (767) were compared with community controls (1,367). We found that a number of reproductive and contraceptive factors that suppress ovulation, including gravidity, breast feeding, and oral contraception, reduced the risk of ovarian cancer. Environmental factors and medical conditions that increased risk included talc use, endometriosis, ovarian cysts, and hyperthyroidism. Gynecologic surgery including hysterectomy and tubal ligation were protective. Tubal ligation afforded a risk reduction even 20 or more years after the surgery. The spectrum of associations provides support for the hypothesis that inflammation may mediate ovarian cancer risk.

Prevention of Allograft Rejection by Use of Regulatory T Cells With an MHC-Specific Chimeric Antigen Receptor

CD4⁺ CD25^high FOXP3⁺ regulatory T cells (Tregs) are involved in graft-specific tolerance after solid organ transplantation. However, adoptive transfer of polyspecific Tregs alone is insufficient to prevent graft rejection even in rodent models, indicating that graft-specific Tregs are required. We developed a highly specific chimeric antigen receptor that recognizes the HLA molecule A*02 (referred to as A2-CAR). Transduction into natural regulatory T cells (nTregs) changes the specificity of the nTregs without alteration of their regulatory phenotype and epigenetic stability. Activation of nTregs via the A2-CAR induced proliferation and enhanced the suppressor function of modified nTregs. Compared with nTregs, A2-CAR Tregs exhibited superior control of strong allospecific immune responses in vitro and in humanized mouse models. A2-CAR Tregs completely prevented rejection of allogeneic target cells and tissues in immune reconstituted humanized mice in the absence of any immunosuppression. Therefore, these modified cells have great potential for incorporation into clinical trials of Treg-supported weaning after allogeneic transplantation.

Progesterone metabolite allopregnanolone in women with premenstrual syndrome

OBJECTIVE

To evaluate the anxiolytic 3alpha-5alpha-reduced progesterone metabolite allopregnanolone in the luteal phase of the menstrual cycle in women with premenstrual syndrome (PMS) and controls.

METHODS

Thirty-five women with prospectively documented PMS and 36 controls were evaluated. Serum progesterone and allopregnanolone levels were measured on days 19 and 26 of the cycle as determined by urinary LH detection kits. Analysis of variance and Student t tests were used to analyze the data.

RESULTS

Allopregnanolone levels were significantly lower on day 26 in the PMS group than in controls (3.6 +/- 0.8 versus 7.5 +/- 1.3 ng/mL; P < .04). Significant differences in the ratio of the metabolite to progesterone also were noted, with a smaller ratio in the PMS subjects (0.9 +/- 0.3 versus 3.2 +/- 1.3 ng/mL; P < .05). There were no significant differences between the PMS and control groups with respect to serum progesterone levels.

CONCLUSION

Subjects with PMS manifested lower levels of the anxiolytic metabolite allopregnanolone in the luteal phase when compared with controls. Diminished concentrations of allopregnanolone in women with PMS may lead to an inability to enhance gamma aminobutyric acid-mediated inhibition during states of altered central nervous system excitability, such as ovulation or physiologic or psychological stress. The lowered metabolite levels could contribute to the genesis of various mood symptoms of the disorder, such as anxiety, tension, and depression.

Predicting antimicrobial susceptibilities for Escherichia coli and Klebsiella pneumoniae isolates using whole genomic sequence data

OBJECTIVES

Whole-genome sequencing potentially represents a single, rapid and cost-effective approach to defining resistance mechanisms and predicting phenotype, and strain type, for both clinical and epidemiological purposes. This retrospective study aimed to determine the efficacy of whole genome-based antimicrobial resistance prediction in clinical isolates of Escherichia coli and Klebsiella pneumoniae.

METHODS

Seventy-four E. coli and 69 K. pneumoniae bacteraemia isolates from Oxfordshire, UK, were sequenced (Illumina HiSeq 2000). Resistance phenotypes were predicted from genomic sequences using BLASTn-based comparisons of de novo-assembled contigs with a study database of >100 known resistance-associated loci, including plasmid-associated and chromosomal genes. Predictions were made for seven commonly used antimicrobials: amoxicillin, co-amoxiclav, ceftriaxone, ceftazidime, ciprofloxacin, gentamicin and meropenem. Comparisons were made with phenotypic results obtained in duplicate by broth dilution (BD Phoenix). Discrepancies, either between duplicate BD Phoenix results or between genotype and phenotype, were resolved with gradient diffusion analyses.

RESULTS

A wide variety of antimicrobial resistance genes were identified, including blaCTX-M, blaLEN, blaOKP, blaOXA, blaSHV, blaTEM, aac(3')-Ia, aac-(3')-IId, aac-(3')-IIe, aac(6')-Ib-cr, aadA1a, aadA4, aadA5, aadA16, aph(6')-Id, aph(3')-Ia, qnrB and qnrS, as well as resistance-associated mutations in chromosomal gyrA and parC genes. The sensitivity of genome-based resistance prediction across all antibiotics for both species was 0.96 (95% CI: 0.94-0.98) and the specificity was 0.97 (95% CI: 0.95-0.98). Very major and major error rates were 1.2% and 2.1%, respectively.

CONCLUSIONS

Our method was as sensitive and specific as routinely deployed phenotypic methods. Validation against larger datasets and formal assessments of cost and turnaround time in a routine laboratory setting are warranted.

The SF-36 health survey questionnaire: is it suitable for use with older adults?

An Anglicized version of the SF-36, a recently developed generic health status measure, was tested among people aged 65 years and over in hospital outpatient and general practice settings as both a self-completed and interview-administered instrument. The SF-36 was quick to complete, with 84% completed in 10 minutes or less (median time 8 minutes), while the distribution of scores provided further evidence of its sensitivity and validity. As an interview-administered instrument the SF-36 was acceptable among all age groups, although 32% of outpatients and 10% of general-practice patients, consisting predominantly of people aged 75 years and over with poor physical or mental health scores, felt unable to self-complete the questionnaire. In addition, 26% of respondents missed out at least one of the 36 statements, with missing items being significantly related to older age and self-completion. Missing responses were mainly concentrated on a small number of questions whose emphasis on work or vigorous activities meant that they were frequently regarded as not applicable by elderly people. Suggested modifications to these questions for elderly respondents are given. With these changes the SF-36 is regarded as suitable for use as a self-completed questionnaire among the younger age group of elderly people, although some assistance may often be required by people aged 75 years and over and especially those with poor physical or mental health.

Methylated, blocked 5 termini in HeLa cell mRNA

Poly(A)-containing HeLa cell mRNA prepared from cells labeled with [methyl-(3)H]methionine or [(32)P]phosphate was found to contain a variety of methylated, blocked 5'-terminal structures of two general types: m(7)GpppN(7)-Np and m(7)GpppN(m)-N(m)-Np. In addition, about one-third of the [(3)H]methyl label was present in the N(6)-methyladenosine; this labeled nucleoside was not found in the 3'-terminal one-third of the mRNA chain and thus may also be in the 5' portion of the mRNA.

Amniotic fluid embolism

The statement that amniotic fluid embolism is the most dangerous and untreatable condition in obstetrics appears to be true. It must be suspected in any patient who collapses or bleeds excessively during labour or the immediate post-partum period. Attempts should be made to secure a definitive diagnosis in life by examination of blood obtained from the right side of the heart and the sputum for elements of amniotic fluid. Lung scanning is a useful aid to diagnosis. The principal factors that have been implicated in the clinical syndrome of amniotic fluid embolism are anaphylaxis, vascular obstruction by particulate matter, vascular spasm due to prostaglandins and possibly some other vasoactive substances, and the possibility that all the changes could be explained by disseminated intravascular coagulation as a primary event. Further work is required to elucidate the relative contributions of these various factors. Due to the suddeness of the catastrophe and the very high mortality, haemodynamic data in humans is virtually non-existent. With improved methods of resuscitation it is to be hoped that the mortality rate will be reduced and that such data will become available. In this way it might become possible to apply the results of animal research and indicate the most effective method of treatment.

Myosin light-chain phosphatase

1. A method for the isolation of a new enzyme, myosin light-chain phosphatase, from rabbit white skeletal muscle by using a Sepharose-phosphorylated myosin light-chain affinity column is described. 2. The enzyme migrated as a single component on electrophoresis in sodium dodecyl sulphate/polyacrylamide gel at pH7.0, with apparent mol.wt. 70000. 3. The enzyme was highly specific for the phosphorylated P-light chain of myosin, had pH optima at 6.5 and 8.0 and was not inhibited by NaF. 4. A Ca2+-sensitive 'ATPase' (adenosine triphosphatase) system consisting of myosin light-chain kinase, myosin light-chain phosphatase and the P-light chain is described. 5. Evidence is presented for a phosphoryl exchange between Pi, phosphorylated P-light chain and myosin light-chain phosphatase. 6. Heavy meromyosin prepared by chymotryptic digestion can be phosphorylated by myosin light-chain kinase. 7. The ATPase activities of myosin and heavy meromyosin, in the presence and absence of F-actin, were not significantly changed (+/- 10%) by phosphorylation of the P-light chain.

Results of treatment for soft tissue sarcoma in childhood and adolescence: a final report of the German Cooperative Soft Tissue Sarcoma Study CWS-86

PURPOSE

The goal of the second German Soft Tissue Sarcoma Study CWS-86 (1985 to 1990) was to improve the prognosis in children and adolescents with soft tissue sarcoma by means of a clinical trial comprising intensive chemotherapy and risk-adapted local therapy.

PATIENTS AND METHODS

There were 372 eligible patients. A staging system based on the postsurgical extent of disease was used. Chemotherapy consisted of vincristine, dactinomycin, doxorubicin, and ifosfamide. Radiotherapy was administered early at 10 to 13 weeks simultaneously with the second chemotherapy cycle (32 Gy or 54. 4 Gy). The single dose was reduced to 1.6 Gy and given twice daily (accelerated hyperfractionation).

RESULTS

The event-free survival (EFS) and overall survival rates at 5 years were 59% +/- 3% and 69% +/- 3%, respectively. The 5-year EFS rate according to stage was as follows: stage I, 83% +/- 5%; stage II, 69% +/- 6%; stage III, 57% +/- 4%; and stage IV, 19% +/- 6%. The outcome for patients with stage III disease who required radiotherapy was much better in the CWS-86 study compared with the CWS-81 study (5-year EFS, 60% +/- 5% v 44% +/- 6%; P =.053). The most common treatment failure was isolated local relapse, with 14% of patients relapsing at the primary tumor site.

CONCLUSION

The improved design of the study incorporating risk-adapted radiotherapy allowed treatment to be reduced for selected groups of patients without compromising survival.

Risk of ovarian cancer in relation to estrogen and progestin dose and use characteristics of oral contraceptives. SHARE Study Group. Steroid Hormones and Reproductions

Although past studies have shown that oral contraceptives with 50 microg or more of estrogen reduce the risk of ovarian cancer, it is not clear whether newer, lower-dose formulations do as well. We conducted a population-based, case-control study in the Delaware Valley to assess the impact of dose of oral contraception on risk of ovarian cancer. Cases aged 20-69 years with a diagnosis of epithelial ovarian cancer ascertained between May 1994 and July 1999 (n = 767) were compared with community controls (n = 1,367). Compared with never users, the adjusted risk of ovarian cancer was reduced by 40% for oral contraceptive users overall, with longer duration of use affording greater protection. The ovarian cancer risk reduction was similar for women who initiated oral contraception before 1972, when high-dose pills dominated the market; between 1972 and 1980; and after 1980, when newer, lower-dose pills dominated. Oral contraceptive estrogen and progestin content were compared for cases and controls after adjustment for current age, number of pregnancies, race, and family history of ovarian cancer. Use of low-estrogen/low-progestin pills afforded an estimated risk reduction (odds ratio = 0.5, 95% confidence interval: 0.3, 0.6) that was identical to that for high-estrogen/high-progestin pills (odds ratio = 0.5, 95% confidence interval: 0.3, 0.7).

Sickness absence and 'working through' illness: a comparison of two professional groups

BACKGROUND

Few studies have investigated occupational groups reporting low rates of sickness absence because of an assumption that these rates indicate low morbidity. This is inconsistent with the view that sickness absence, which may be caused by social and psychological rather than medical factors, does not equate with morbidity. This paper investigates rates of sickness absence and factors influencing decisions not to take sick leave among doctors and a comparative professional group.

METHODS

A postal survey was sent to 670 general practitioners (GPs), 669 hospital doctors and 400 company 'fee earners'. Qualitative interviews were conducted with 64 doctors reporting an illness lasting one month or more in the last three years.

RESULTS

Self-reported health status was similar for both groups but GPs reported higher levels of occupational stress. However, doctors were significantly less likely to report short periods of sick leave in the previous year. Over 80 per cent of all respondents had 'worked through' illness, citing cultural and organizational factors behind their decision not to take sick leave. Barriers to sick leave among doctors included the difficulty of arranging cover and attitudes to their own health.

CONCLUSIONS

Considerable emphasis has been given to the role of social factors in contributing to rates of sickness absence. These may also contribute to the decision not to take sick leave, resulting in possible inappropriate non-use. Measures to encourage and enable doctors to take sick leave might improve the management of their own health.

Comparison of self-report, video observation and direct measurement methods for upper extremity musculoskeletal disorder physical risk factors

The prevention of work-related musculoskeletal disorders has become a national priority in many countries. Increasingly, attempts are made to quantify those exposures that increase risk in order to set exposure limit values. This study used commonly employed field measurement methods and tools in order to perform an inter-method comparison between three primary methods of risk factor exposure assessment: self-report questionnaires, observational video analysis and direct measurement. Extreme posture duration, repetition, hand force (estimated from electromyography) and movement velocity were assessed for 18 subjects while performing each of three jobs processing tree seedlings. Results indicated that self-reports were the least precise assessment method, which consistently overestimated exposures for each of the measured risk factors. However, adjustment of the reports as psychophysical scales may increase agreement on a group level. Wrist flexion/extension duration and repetition were best measured by electrogoniometer. Electrogoniometric measures of wrist deviation duration and frequency were less precise than video analysis. Forearm rotation duration and repetition, grip force and velocity appeared to be best quantified by direct measurement as measured by electrogoniometer and electromyography (EMG) (as root-mean-square amplitude). The results highlight the fact that it is as important to consider and report estimated measurement error in order to reduce potential exposure misclassification in epidemiologic studies.