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Biomedical subjects

J Ball

Publications and source records attributed to J Ball.

At least 37 records · Page 2Linked to original sources
PubMed2000

Germinal centers without T cells.

Germinal centers are critical for affinity maturation of antibody (Ab) responses. This process allows the production of high-efficiency neutralizing Ab that protects against virus infection and bacterial exotoxins. In germinal centers, responding B cells selectively mutate the genes that encode their receptors for antigen. This process can change Ab affinity and specificity. The mutated cells that produce high-affinity Ab are selected to become Ab-forming or memory B cells, whereas cells that have lost affinity or acquired autoreactivity are eliminated. Normally, T cells are critical for germinal center formation and subsequent B cell selection. Both processes involve engagement of CD40 on B cells by T cells. This report describes how high-affinity B cells can be induced to form large germinal centers in response to (4-hydroxy-3-nitrophenyl) acetyl (NP)-Ficoll in the absence of T cells or signaling through CD40 or CD28. This requires extensive cross-linking of the B cell receptors, and a frequency of antigen-specific B cells of at least 1 in 1,000. These germinal centers abort dramatically at the time when mutated high-affinity B cells are normally selected by T cells. Thus, there is a fail-safe mechanism against autoreactivity, even in the event of thymus-independent germinal center formation.

Animals↗
PubMed2000

Survey of nationally registered emergency medical services providers: pediatric education.

STUDY OBJECTIVE: To survey emergency medical services (EMS) providers on a national level to determine and describe their perspective regarding their initial and continuing education (CE) needs in pediatrics. METHODS: A 10-question survey was developed, pilot-tested, and sent to EMS providers as a part of their National Registry of Emergency Medical Technicians reregistration materials. RESULTS: Surveys were completed by 18,218 EMS providers, a response rate of 67%. During a typical month, 60% of emergency medical technician-paramedics (EMT-Ps), 84% of EMT-intermediates (EMT-Is), and 87% of basic EMTs (EMT-Bs) care for 0 to 3 pediatric patients. CE was identified by all provider levels as the main source of their pediatric knowledge and skills. A state or national mandate for required CE in pediatrics was supported by 76% of surveyed providers. More than 70% of all providers responded they were comfortable to some degree with their own ability and their EMS system's ability when confronted with a critical pediatric call. Cost, availability, and travel distance were identified by all levels as the primary barriers to obtaining pediatric CE. All levels identified infants as the age of greatest concern if the provider was called to manage a critical case. CONCLUSION: Surveyed practicing nationally registered EMS providers have infrequent contact with pediatric patients and have acquired most of their pediatric knowledge and skills from CE. In general, these providers are comfortable with their personal and their system's ability to care for children, but clearly support the need for required pediatric CE and identify the birth to 3-year age range as the priority for an educational focus. Cost, travel distance, and availability of pediatric CE are barriers that should be considered if pediatric CE is to be required of EMS providers.

Attitude of Health Personnel↗
PubMed2000

Effectiveness of the National Death Index for establishing the vital status of older women in the Australian Longitudinal Study on Women's Health.

OBJECTIVE: To assess the effectiveness of the National Death Index (NDI) in identifying participants in the oldest cohort of the Australian Longitudinal Study on Women's Health (ALSWH) who had died between 1996 and 1998. METHODS: Identifying information for each woman was matched with the NDI using a probabilistic algorithm and clerical review. Differences in full name, date of birth, State of residence and date of last contact were used to assess the probability of a true match. RESULTS: NDI identified 410 matches of death records for 409 women; 386 were categorised as true matches and 23 were doubtful matches. Responses to the follow-up survey confirmed that for six of the doubtful matches the women had died, 16 were alive and the vital status of one woman remained unconfirmed at 30 June 1998. Twelve deaths, known to have occurred before July 1998, were not identified through NDI. The sensitivity of the NDI for identifying known deaths was 95%. Detailed identifying information, particularly the middle name, was important for accurate identification of the vital status. CONCLUSIONS: Using surname, all given names, gender, date of birth, State of residence and age at last contact as matching variables, the NDI was an effective tool for identifying women who had died. IMPLICATIONS: Routinely collected mortality data in the NDI are useful for the practice of epidemiology.

Aged↗
PubMed2000

Why are we waiting.

Explore the source record for details and available documents.

Emergency Nursing↗
PubMed1999

Women drivers' behaviour, socio-demographic characteristics and accidents.

The purpose of this study was to examine factors which affect driving behaviour and accident rates in women in Australia. Two groups of women (aged 18-23 and 45-50 years) participating in the Australian Longitudinal Study on Women's Health, completed a mailed questionnaire on driver behaviour and road accidents. Self reported accident rates in the last 3 years were 1.87 per 100,000 km for the young drivers (n = 1199) and 0.59 per 100,000 km for the mid-age drivers (n = 1564); most accidents involved damage only, not injury. Mean scores for lapses obtained using the Driver Behaviour Questionnaire, were similar in the two age groups and similar to those found in other studies. In contrast, scores for errors and violations for the young women were higher than for the mid-age group and previous reports using the same instruments. Riskier driving behaviour among young women was associated with stress and habitual alcohol consumption. In the mid-age group, poorer driver behaviour scores were related to higher levels of education, feeling rushed, higher habitual alcohol consumption and lower life satisfaction scores. Accident rates in both groups were significantly related to lapses. Women born in non-English speaking countries had significantly higher risk of accidents compared to Australian-born women: relative risk = 3.40, 95% confidence interval (1.93, 5.98) for the young drivers; relative risk = 1.77, 95% confidence interval (1.11, 2.83) for mid-age drivers. These findings support the need for road safety campaigns targeted at young women to reduce dangerous driving practices, such as speeding, 'tail gating' and overtaking on the inside. There is also a need for further research to understand how lifestyle characteristics are associated with higher risk of accidents and to explore factors which might account for the higher risk for women drivers who were born overseas.

Accidents, Traffic↗
PubMed1999

Comparison of the upper gastrointestinal safety of Arthrotec 75 and nabumetone in osteoarthritis patients at high risk for developing nonsteroidal anti-inflammatory drug-induced gastrointestinal ulcers.

A 6-week, multicenter, double-masked, placebo-controlled, parallel-group study compared the upper gastrointestinal (UGI) safety of Arthrotec 75 (diclofenac sodium 75 mg-misoprostol 200 microg; G.D. Searle & Co., Skokie, Illinois) administered twice daily with that of nabumetone 1500 mg administered once daily in 1203 patients with symptomatic osteoarthritis (OA) of the hip or knee. All patients had a documented clinical history of endoscopically confirmed gastric, pyloric-channel, or duodenal ulcer or > or = 10 erosions in the stomach or duodenum. UGI endoscopy was performed at baseline and again at week 6 or early withdrawal. Treatment with Arthrotec 75 resulted in a significantly lower combined incidence of endoscopically confirmed gastric and duodenal ulcers compared with nabumetone (4% vs 11%), and its rate of endoscopically confirmed ulceration was equivalent to that of placebo. The incidence of gastric ulcers alone was also significantly lower with Arthrotec 75 than with nabumetone (1% vs 9%). The incidence of duodenal ulcer with Arthrotec 75 was not significantly different from that with nabumetone (4% vs 3%). Types of adverse events were similar for all treatment groups, with GI adverse events predominating. Arthrotec 75 was well tolerated by the majority of patients. The results of this study demonstrate that Arthrotec 75 has a superior UGI safety profile, causing significantly fewer UGI ulcers, in comparison with nabumetone in patients with symptomatic OA and a documented history of ulcers or > or = 10 erosions.

Adult↗
PubMed1999

Extracorporeal photopheresis (ECP) in the treatment of chronic graft-versus-host disease (GVHD)

The aim of our study was to assess the efficacy of extracorporeal photopheresis (ECP) in chronic graft-versus-host disease (GVHD). Eleven patients with chronic cutaneous GVHD were studied. Four had mucosal involvement and five had pulmonary involvement. All had failed to improve on first- and second-line therapy. Three patients received ECP alone; the remainder continued to receive steroids and/or immunosuppressive therapy. Patients received ECP twice monthly for 4 months and then once monthly for 3 months. They were evaluated by serial skin scores, mucosal and skin photography, pulmonary function tests, biochemical and haematological parameters. Nine patients showed objective evidence of cutaneous improvement with a mean reduction in skin score of 48% overall. In the 10th patient, skin scores and oral involvement improved on twice monthly ECP but deteriorated when reduced to once monthly. The final patient died from renal failure secondary to cyclosporin toxicity. Two out of five patients with lung involvement showed a mild improvement in pulmonary function tests. Liver function tests were abnormal in five patients; they improved in one and deteriorated in three. All patients receiving concomitant immunosuppressive/steroid therapy were able to reduce drug dosages by trial completion. Our results indicate that ECP can benefit patients with cutaneous and mucosal chronic GVHD who have failed on first- and second-line therapies. The effect on the systemic manifestations of GVHD is less consistent.

Adolescent↗
PubMed1998

General practitioners' attitudes to psychiatric and medical illness.

BACKGROUND: General practitioners are increasingly involved in the care of patients with long-term psychiatric disorders. We have previously reported that general practitioners are less willing to treat patients with schizophrenia than those without such a diagnosis, but this may have been attributable to a reluctance to treat patients with any psychiatric or chronic illness. We, therefore, examined general practitioners' attitudes to patients with chronic psychiatric or medical illnesses. METHODS: A random sample of 260 local general practitioners were each sent one of our case vignettes which were identical apart from mention of a previous diagnosis of schizophrenia, depression, diabetes or no illness. The general practitioners were asked to indicate their level of agreement with 13 attitudinal statements based on the vignette. RESULTS: One hundred and sixty-six (66%) of the general practitioners responded to the case vignettes. Those responding to the vignette about the patient with schizophrenia were less happy to have that patient on their practice list and were more concerned about the risk of violence and the child's welfare. Those responding to the depression vignette were more likely to offer the patient antidepressants or counselling; and those who replied to the diabetes case were most likely to refer the patient to a hospital specialist. These differences were not attributable to the personal or practice characteristics of the general practitioners. CONCLUSIONS: Patients with schizophrenia arouse concerns in general practitioners that are not simply due to those patients suffering from a psychiatric or chronic illness. Our results suggest that some patients with schizophrenia may find it difficult to register with a general practitioner and receive the integrated community-based health care service they require. Psychiatrists should provide education and support to general practitioners who look after patients with schizophrenia.

Adult↗
PubMed1998

Preventing and managing childhood emergencies in schools.

The Emergency Medical Services for Children (EMSC) program, initially funded in 1984, is jointly administered by the Health Resources and Services Administration and the National Highway Traffic Administration. The program is designed to reduce child and youth mortality and morbidity resulting from severe illness or trauma. Several initiatives, focused at the federal, state, and local levels, have established collaboration between the education and health communities. They include injury prevention education and programs in school settings; school and staff preparation for a medical emergency; and emergency care planning for school children with special health care needs. This article provides an overview of key issues.

Child↗
PubMed1997

Isospora tiaris n.sp. (Apicomplexa: Eimeriidae) from the sooty grassquit (Tiaris fuliginosa), a passeriform bird of South America.

Isospora tiaris n. sp. is described from the feces of an adult bird, a sooty grassquit (Tiaris fuliginosa) from Venezuela. The oocysts are subspherical, 27.1 x 23.8 (24.7-30.0 x 21.2-26.5) microns with a bilayered, smooth, colorless wall. A micropyle and oocyst residuum are absent; an ellipsoidal polar granule is usually present. Sporocysts are ovoidal, 14.7 x 10.8 (12.4-16.8 x 8.8-12.4) microns with prominent Stieda and substieda bodies and a residuum composed of small uniform granules.

Animals↗
PubMed1996

Very late antigen (VLA) expression by normal and neoplastic human plasma cells; including an assessment of antibodies submitted to the Vth International Workshop on Leucocyte Differentiation Antigens using human myeloma cell lines.

The biology of normal plasma cells and the pathophysiology of human multiple myeloma remain poorly understood. Functional assays are scarce and at present cell phenotyping is providing the most information about how human plasma cells may behave. Three different types of human plasma cells: normal, fresh neoplastic myeloma cells and plasma cell lines, have been studied for their reactivity with antibodies to the beta-1 integrins (Very Late Antigens; VLAs), including a panel obtained from the Vth International Workshop on Leucocyte Differentiation Antigens. Most plasma cell targets express VLA-4 (CD49d positive) and the common beta chain recognized by CD29. CD49e (VLA-5) was occasionally positive. Other VLAs were not usually expressed. These data suggest the wide use by plasma cells of VLA-4, possibly as a ligand with fibronectin and high endothelial venules (HEV). Of other adhesion structures expressed by plasma cells, only CD44 is seen as frequently, and this is also a HEV ligand.

Antibodies↗
PubMed1996

Centrocytes rapidly adopt a memory B cell phenotype on co-culture with autologous germinal centre T cell-enriched preparations.

B cells, after mutating their Ig B-region genes in germinal centres (GC), undergo apoptosis, unless they receive antigen-dependent selection signals. The signals appear to be delivered by GC T cells, require CD40 ligand expression and may induce differentiation to memory cells. Cultured GC B cells are prevented from entering apoptosis by ligating their surface CD40, but the resulting phenotype is not associated with B cells found in vivo. Conversely, GC B cells rapidly adopt a memory B cell phenotype on culture with autologous memory CD4(+) T cells that have been induced to express CD40 ligand transiently. This effect is prevented by blocking CD40 ligand. Naive CD4(+) T cells, induced to express CD40 ligand, do not prevent GC B cells undergoing apoptosis.

Adolescent↗
PubMed1996

4-Hydroperoxycyclophosphamide purged autologous bone marrow transplantation in non-Hodgkin's lymphoma patients at high risk of bone marrow involvement.

Between June 1990 and January 1994, 19 patients with non-Hodgkin's lymphoma (NHL) at high risk for bone marrow involvement underwent 4-hydroperoxycyclophosphamide (4-HC) purged bone marrow transplantation. Eleven patients had low grade, seven intermediate grade and one high grade NHL and 7/19 patients had received three or more previous chemotherapeutic regimens. Four patients were transplanted in first partial remission (PR) and the remainder in responsive relapse. Fourteen patients had bone marrow (BM) involvement at diagnosis and/or at relapse. The median times to granulocyte and platelet recovery were 26 and 29 days, respectively. There were two toxic deaths and one complete responder developed secondary AML at 31 months post-BMT. Seventeen of 18 evaluable patients achieved a complete remission (CR) and one patient a PR. Fourteen patients (74%) are progression-free at a median follow-up of survivors of 34 months (range 29-55). The 3 year event-free (EFS) and overall survival (OS) probabilities are both 67%. No statistically significant difference was seen between EFS or OS and BM involvement or histologic grade at diagnosis. At 29 months, 4/7 patients with a morphologically involved BM harvest had relapsed or died compared to 1/12 patients with negative BM (P = 0.03). These results are encouraging and warrant further investigation of 4-HC purging in NHL.

Adult↗