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Biomedical subjects

J O'Brien

Publications and source records attributed to J O'Brien.

At least 181 records · Page 10Linked to original sources
PubMed1992

The sonographically thick placenta: a predictor of increased perinatal morbidity and mortality.

In order to determine the prevalence and significance of sonographically thick placentas, we reviewed the computerized records of 18 827 viable, singleton pregnancies. Of these, 116 (0.6%) had thick placentas diagnosed by ultrasound examination. Perinatal mortality was markedly increased among pregnancies with thick placentas (odds ratio = 13.1, 95% confidence limits (CL) = 8.3-20.8), accounting for 6.2%; of the total. The rates of abruptio placentae (odds ratio = 2.9, CL = 1.1-8.1), neonatal intensive care unit admissions (odds ratio = 4.6, CL = 3.1-6.9) and anomalies (odds ratio = 8.4, CL = 4.9-14.4) were also significantly increased among the thick placenta cohort compared to controls. The 106 liveborn neonates with thick placentas had lower Apgar scores, were delivered at an earlier gestational age, and weighed less than controls. Anomalies, hydrops fetalis and abruptio placentae complicated 16 of the 24 cases of perinatal mortalities. Sonographically thick placentas should alert the clinician to the possibility of compromised perinatal outcome.

Journal Article↗
PubMed1992

Localized conformational changes in the N-terminal domain of CD4 identified in competitive binding assay of monoclonal antibodies and HIV-1 envelope glycoprotein.

The CD4 antigen is established as a major cellular receptor for the human immunodeficiency virus (HIV). Previous studies have suggested that certain anti-CD4 monoclonal antibodies (MAbs) can inhibit or enhance the binding of the viral envelope glycoprotein gp120 to CD4 by allosteric effects. In the study reported here, 17 anti-CD4 MAbs were tested for their ability to influence the binding of each other to recombinant soluble CD4 in a solid-phase radioimmunoassay. Marked enhancement of binding between specific pairs of MAbs was seen, as well as inhibition or lack of interaction. Enhancement was seen less often when CD4+ cells were used as the target antigen. Information on patterns of enhancement and inhibition permitted grouping of MAbs on the basis of epitope specificity, and this grouping was in agreement with published findings based on X-ray crystallographic studies. These results demonstrate connectivity between epitopes in the first domain of recombinant CD4 and suggest a high degree of flexibility of surface structure. These findings may be of physiological significance both in the normal function of CD4 and in the interaction of CD4 with HIV. The data have implications for research or therapeutic strategies based on recombinant CD4 or CD4 mutants and highlight the problems of interpreting experimental findings based on abrogation of MAb binding.

Antibodies, Monoclonal↗
PubMed1992

A methodology for collecting outcome measures for common hospital conditions.

An eight-month prospective analysis of routinely collected hospital data with 24-week follow-up of mortality and morbidity was carried out at two district general hospitals in Somerset Health District, to test the feasibility of collecting useful and valid outcome measures for two common hospital conditions, strokes and fractured hips. Data were collected on 163 consecutive admissions with a primary diagnosis of stroke (83 cases) or fractured hip (80 cases). At 24 weeks, 38 patients with stroke had died (mortality ratio 46 per cent, 95 per cent C.I. = 35.3-56.7 per cent) and 11 with fractured hip had died (mortality ratio 14 per cent, 95 per cent C.I. = 6.4-21.6 per cent). Seven patients (four with fractured hip and three with stroke) died after 24 weeks and before responding to the NHP questionnaire. One stroke patient could not be traced. Nottingham Health Profiles were received from 106 patients (41 with stroke and 65 with fractured hip). Both groups of patients had problems with physical mobility and lack of energy. Patients with fractured hips were more likely to complain of pain. It is concluded that the methods used to collect outcome measures in this study are widely applicable to other conditions, but the interpretation and comparability of the results require the collection of similar data elsewhere.

Aged↗
PubMed1992

Patterns of regional cerebral blood flow in Alzheimer's disease.

Regional cerebral blood flow was assessed in 35 patients with Alzheimer's disease and the same number of matched normal volunteers. Images were scored for regional perfusion deficits. Mildly demented patients had parietal and temporal perfusion deficits, often unilateral. Moderate to severely demented patients had bilateral temporal and parietal perfusion deficits. All severely demented patients also had involvement of both occipital regions. Frontal lobe deficits were seen in 14 patients. Left cortical perfusion deficits were more severe than the right cortical perfusion deficits in general. Patients with early onset of the disease showed left frontal deficits, more often, however, the total perfusion deficit scores in early and late onset groups were not statistically significant. Also, the cognitive performance scores were not statistically significant in these two groups. These results suggest a stage-dependent reduction in regional cerebral blood flow in patients with Alzheimer's disease.

Aged↗
PubMed1992

Recovery of leukotriene E4 from the urine of patients with airway obstruction.

The urinary excretion of leukotriene E4 (LTE4) was measured in subjects presenting for emergency treatment of airway obstruction. A total of 72 subjects presenting with airway obstruction performed peak flow determinations before and after three treatments with nebulized albuterol given at 20-min intervals. Of these subjects, 22 more than doubled their peak flow rates, while 19 failed to increase their peak flow rates more than 25% during the treatment period. These groups were designated "responders" and "nonresponders," respectively. Urinary LTE4 excretion was determined in 16 of the 22 responders and 12 of the 19 nonresponders as well as 13 normal subjects by precolumn extraction, analytic reversed-phase high-performance liquid chromatography, and enzyme immunoassay. In the normal subjects the urinary LTE4 excretion was significantly (p less than 0.0001) less than the urinary LTE4 measured in the responder subjects, but not less than the urinary LTE4 excretion in the nonresponder group (p = 0.071). The enhanced recovery of LTE4 from the urine of subjects with acutely reversible airway narrowing is consistent with a bronchoconstrictor role for the cysteinyl leukotrienes in spontaneous acute asthma.

Acute Disease↗
PubMed1992

Closing the asylums: where do all the former long-stay patients go?

The ongoing closure of the old asylums has resulted in large numbers of potentially vulnerable people living in the community. Where are these patients now and how are they coping? This study answers these questions in relation to a cohort of former long-stay patients discharged between 1985 and 1989 in Somerset Health District. The findings show that, as a group, they are a settled non-mobile population whose residential setting is not under threat. However, day care arrangements are inadequate with 45% of the study population without any structured day care. Most patients had unmet needs in the categories 'living space', 'work' and 'leisure'. Such studies are simple to conduct, and require little research funding. This methodology is recommended as a crude means of measuring unmet needs in this group of vulnerable individuals.

Community Mental Health Services↗
PubMed1992

Five DNA tumor viruses undetectable in human retinoblastomas.

Retinoblastoma (RB) is a childhood eye cancer that arises when a retinal cell lacks a functional RB gene. Recent data indicate the transforming proteins of adenovirus, papillomavirus, and the polyomaviruses BK and JC all can bind to the product of the RB gene. Furthermore, adenovirus 12, JC virus, and simian virus 40 are able to induce RB-like tumors in rodents. In view of these findings, 50 human RBs were tested for the presence of five human DNA tumor viruses: adenovirus 12, BK virus, JC virus, and human papillomaviruses 16 and 18. Using the polymerase chain reaction, no viral sequences were detected in 50 RB DNAs. These data provide no evidence that these viruses have an etiologic role in human RB.

Base Sequence↗
PubMed1991

Urinary incontinence: prevalence, need for treatment, and effectiveness of intervention by nurse.

OBJECTIVE: To measure the unmet need of patients with regular urinary incontinence (incontinence twice or more a month) treatable by a nurse. DESIGN: Self completed postal questionnaire and randomised controlled trial of assessment and intervention by a nurse. SETTING: One urban and one rural general practice in Somerset. SUBJECTS: 7300 adults randomly selected from 10,300 aged 35 and over on the combined practice lists. 515 women and 185 men with regular incontinence were offered assessment and treatment, of whom 134 women and 49 men had no intervention for three months (historical controls). They then joined the assessment and treatment programme. INTERVENTION: Four sessions of pelvic floor exercises and bladder retraining supervised by non-specialist nurse who had taken a three week course on assessing and treating uncomplicated incontinence. MAIN OUTCOME MEASURES: Number of patients desiring treatment; self reported cure, improvement, or deterioration in continence after three months. RESULTS: The questionnaire achieved a 79% response. Validated responses showed a prevalence of 4.4% in men and 16.4% in women aged 35-64. 315 (45%) of the 700 patients offered assessment refused it and seven had moved away or died, 64 men and 41 women were referred to their general practitioner. 197 of 292 treated women (68%) reported cure or improvement compared with seven (5%) of controls. 22 of the 86 men desiring treatment were suitable for intervention by the nurse. Seventeen were cured or improved compared with none of the men in the control group. CONCLUSIONS: About half the people with regular urinary incontinence took up the offer of treatment (9.2% of women and 3.4% of men in the study population). This condition can be effectively managed by a nurse with limited training.

Adult↗
PubMed1991

Comparison of ZFY and ZFX gene structure and analysis of alternative 3' untranslated regions of ZFY.

We have cloned and sequenced transcripts from the X- and Y-linked zinc-finger genes ZFX and ZFY respectively and discuss a possible mechanism of post-transcriptional control by which these genes can be widely expressed but translated in only specific tissues. We report the identification of a novel 3'UTR (untranslated region) present in ZFY which is highly conserved among primates and contains a series of motifs implicated as mRNA instability determinants. These sequences can be substantially removed by polyadenylation directed from consensus (AATAAA) and non-consensus (AATATAAA) sequences in adult testis. The DNA-binding domains of the ZFY and ZFX proteins are compared using present models for zinc-finger/DNA interactions. Additionally, the genomic organisation of the ZFY coding sequence is presented as compared to that of ZFX.

Amino Acid Sequence↗
PubMed1991

Polymerization site in the beta chain of fibrin: mapping of the B beta 1-55 sequence.

The formation of a fibrin clot occurs through binding of putative complementary sites, called fibrin polymerization sites, located in the NH2- and COOH-terminal domains of fibrin monomer molecules. In this study, we have investigated the structure of the NH2-terminal fibrin polymerization site by using fibrinogen-derived peptides and fragments. Fibrinogen was digested with Crotalus atrox protease III, to two major molecular species: a Mr 325,000 derivative (Fg325) and a peptide of Mr 5000. The peptide and its thrombin-cleavage product were purified by ion-exchange and reverse-phase HPLC; the authenticity of the B beta 1-42 and beta 15-42 peptides, respectively, was confirmed by amino acid sequencing. Since Fg325 had decreased thrombin coagulability, we addressed the question of whether the peptide B beta 1-42 contained a fibrin polymerization site. In order to identify and map the site, the peptides B beta 1-42 and beta 15-42 were tested for their ability to inhibit fibrin monomer polymerization. In addition the following peptides prepared by chemical synthesis were also tested: beta 15-18, beta 15-26, beta 24-42, beta 40-54, beta 50-55, and alpha 17-19-Pro. While B beta 1-42 had no inhibitory activity, the peptide devoid of fibrinopeptide B, beta 15-42, was a strong inhibitor. The peptides beta 15-18, beta 15-26, and beta 15-42 decreased the rate of fibrin polymerization by 50% at a molar excess of the peptide to fibrin monomer of 500, 430, and 50, respectively. The peptides beta 24-42, beta 40-54, and beta 50-55 were inactive.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1991

Mitoxantrone, etoposide, mitoguazone and vinblastine chemotherapy (MV2) in relapsed and refractory lymphomas.

As part of a program to develop less leukemogenic chemotherapy regimens for the treatment of favorable prognosis Hodgkin's disease, a phase I-II trial of mitoxantrone, etoposide, mitoguazone, and vinblastine was used to treat patients with relapsed and refractory malignant lymphoma and Hodgkin's disease. An overall partial response rate of 41% was observed. Although useful responses were seen, the absence of complete remissions is disappointing.

Adolescent↗
PubMed1991

Untoward reaction to adenosine therapy for supraventricular tachycardia.

Adenosine, a naturally occurring nucleoside that slows conduction through the atrioventricular node, has recently been approved for the treatment of supraventricular tachycardia. It has been shown to convert patients with supraventricular tachycardia to sinus rhythm in up to 92% of cases. Its intravascular half-life of only 10 seconds and absence of reported serious side effects have made adenosine an attractive antiarrhythmic agent. This report describes two cases in which significant side effects from the administration of adenosine were encountered including: (1) prolonged sinus arrest with syncope, and (2) syncope with prolonged bradycardia and hypotension. Emergency physicians should be cognizant of the potential complications resulting from adenosine administration, and should be prepared to deal with them when using this newly available agent.

Adenosine↗
PubMed1991

Clinical use of dreams with latency-age children.

Although various authors have discussed the technical modification required for dream interpretation with children, the basic conceptualization of the psychotherapeutic use of the dream with children has remained virtually identical to that with adult analysands. Examining various sources including formal studies on the nature of children's dreams, clinical case reports and series, and cognitive theories, the authors conclude that a dream arising in the course of a child's therapy must be conceptualized theoretically as a posttraumatic phenomenon. This holds whether or not there has been overt trauma to the child. The reasons for the conceptualization include both the heightened degree of anxiety contained in a dream reported in the course of psychotherapy as well as the specific cognitive abilities of children to contain anxiety and abstract and generalize symbolic meanings. A specific technique based on this conceptualization is then detailed that calls for translation of the dream into more tangible expression (drawing, play, etc.) and a noninterpretative approach. The authors also discuss the more general problem of the nature of insight in children.

Child↗