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Biomedical subjects

A Williams

Publications and source records attributed to A Williams.

At least 379 records · Page 21Linked to original sources
PubMed1994

Pulmonary function in infants with cystic fibrosis: the effect of antibiotic treatment.

Since 1982 all infants born within the East Anglian Regional Health Authority have been screened for cystic fibrosis. Between April 1985 and April 1992 infants identified in this way have been entered into a randomised prospective controlled trial of antibiotic prophylaxis. Approximately half the infants received continuous oral flucloxacillin and the remainder received antibiotics when clinically indicated. Infants underwent tests of respiratory function at 3-4 months and at 1 year of age. Measurements of thoracic gas volume and airway conductance were made with an infant whole body plethysmograph, and maximum expiratory flow by the 'squeeze' technique. A total of 73 tests was performed of 42 infants. To facilitate comparisons, measurements were expressed as scores. The mean values of the scores for the two groups of infants fell within normal limits. There was no difference between the treatment groups at either age. A reduction in airways conductance was observed between the two tests.

Administration, Oral↗
PubMed1994

Raised concentration of plasma creatine kinase BB isoenzyme in myelodysplasia.

A 72 year old woman presented with a suspected myocardial infarction. An echocardiograph showed no acute changes but her plasma creatine kinase (CK) activity was increased at 343 U/l (< 175 normal range). The apparent creatine kinase-MB activity by a CK-M subunit immunoinhibition assay was 350 U/l. In view of the discrepancy between the total creatine kinase and CK-MB activity plasma creatine kinase electrophoresis studies were performed which showed not only a band of creatine kinase-MM but also a band of creatine kinase-BB, 53% of the total creatine kinase activity. No band of CK-MB was seen. It later transpired that the woman had myelodysplasia. It is suggested that premalignant and malignant haematological conditions should be considered in patients with an unexplained increase in plasma CK-BB.

Aged↗
PubMed1994

Lay people's evaluations of health: are there variations between different subgroups?

STUDY OBJECTIVE: To elicit lay concepts of health and to see whether these are related to various sociodemographic factors, as has been suggested by previous smaller studies. DESIGN AND SETTING: A total of 196 people aged 18 and over were selected, as a representative sample of the general population, from the electoral registers of Walsall and Dudley in the West Midlands. Respondents were interviewed in their own homes in the autumn of 1989. MEASUREMENTS: Open ended and structured questions were used to elicit concepts of health. The three main stages consisted of an unprompted section in which respondents were asked to describe the features of good or poor health in themselves or others; a prompted section in which they were asked to rate 37 health statements using a series of categories from "very important" to "not at all important"; and a section in which they were asked to indicate which of six groups of statements, each representing a particular concept of health, best represented their own notions of health. RESULTS: Health was seen as multidimensional. Irrespective of whether respondents addressed health in self or health in others, or good or poor health, the biomedical dimension remained an important one. The manner by which concepts of health are elicited may provide some explanation as to why so many and varied concepts are alleged to be held by different subgroups of the population (notably different social classes). CONCLUSIONS: The differences found in this study between models of health employed by different subgroups of the general population have not been as great as has previously been suggested in the published reports. This is encouraging for those using existing health status measurements.

Adolescent↗
PubMed1994

Patronizing the young: forms and evaluations.

Exploratory work indicated that Californian undergraduates were frequently, and irritatingly, patronized by older adults in a variety of ways. In a follow-up, using multidimensional scaling procedures, three distinct clusters representing young adults' own conceptions of patronizing speech emerged ("non-listening," "disapproving," and "parental"). In the main study, young adults were provided with a single vignette of a short conversation between an older and younger person. Eight versions of this vignette were devised independently varying elder's age (40- vs. 70-years) and speech style (neutral vs. non-listening vs. disapproving vs. parental). Participants were required to evaluate both vignette-targets. As expected, the patronizing elders were negatively perceived. An evaluative hierarchy differentiated between the three patronizing forms, and in ways that differed depending on the nature of the judgmental task. Content analyses of open-ended data also revealed interesting differences in interpretive responses to the various vignette conditions.

Adolescent↗
PubMed1994

Small bowel tumours: a diagnostic challenge.

In a 20-year retrospective study of 43 patients having surgery for small bowel neoplasia in a district general hospital, the commonest pathologies were lymphoma (12), carcinoid (12) and adenocarcinoma (11). Malignant neoplasms occurred in 38 patients presenting on average at 68 years of age. In 4 patients a synchronous gastrointestinal neoplasm was found. The average duration of symptoms was 11 weeks for operated patients. In 31 patients the presentation was as a surgical emergency. Only 10 had imaging investigations prior to emergency presentation from which diagnostic information was obtained in 1 patient and helpful information in a further 4. The 5-year survival figures of patients with small bowel neoplasia were carcinoid (50%), lymphoma (27%) and adenocarcinoma (15%), reflecting the poor prognosis of these patients even after 'curative resection'. Patients with carcinoid tumours were the exception, as long-term survival was not unusual even without complete resection of all macroscopic disease.

Adenocarcinoma↗
PubMed1994

Clinical findings and respiratory function in infants following repair of oesophageal atresia and tracheo-oesophageal fistula.

Survival rates for infants undergoing surgical repair of oesophageal atresia with tracheo-oesophageal fistula (OA-TOF) have improved dramatically, but this condition remains associated with substantial morbidity. Most studies of patients following OA-TOF repair have concentrated on school-age and older people; whereas, the most hazardous period is infancy. We aimed to assess respiratory function in a group of infants following primary operative repair, and to relate the results to clinical findings during the first year of life. We studied 16 infants within 3 months of primary repair of OA-TOF. Measurements were made of maximum expiratory flow at functional residual capacity (VmaxFRC), thoracic gas volume (TGV) and airways resistance (Raw). Ten infants had tests repeated, usually to assess progress alongside continuing symptoms, or to ascertain improvement following additional surgery. Seven infants had essentially normal initial respiratory function tests, and six remained either symptom-free or developed only minor clinical problems. One infant subsequently developed stridor, with spontaneous improvement towards the end of the first year. The remaining nine infants had abnormal initial respiratory function tests: one was symptom-free at that time. The remainder developed respiratory and/or gastro-oesophageal symptoms. The functional abnormalities appeared to reflect the severity of the clinical problems encountered. We conclude that respiratory function testing in infants following OA-TOF repair may augment the value of clinical appraisal, help define postoperative respiratory status, and provide a general guide to likely clinical progress.

Airway Resistance↗
PubMed1993

Expression of GlyCAM-1, an endothelial ligand for L-selectin, is affected by afferent lymphatic flow.

The interaction of naive, L-selectin-bearing lymphocytes with counterreceptors on the surface of high endothelial venules (HEV) is the initial step in the extravasation of these cells from the bloodstream into the peripheral lymph node. Recently, two sulfated glycoprotein ligands, 50 and 90 kDa, respectively, have been identified as ligands for L-selectin using an L-selectin-IgG chimera. cDNA cloning of one of these molecules, the 50-kDa sulfated glycoprotein (glycosylation-dependent cell adhesion molecule 1 [GlyCAM-1]), has shown it to be a mucinlike scaffold that presents a carbohydrate ligand(s) to the lectin domain of L-selectin. Herein, we analyze the factors that might regulate the expression of these ligands. Ligation of afferent lymphatics results in a complete loss of the mRNA for GlyCAM-1. In addition, L-selectin-mediated adhesion, as inferred by binding of an L-selectin-IgG chimera, is also lost on interruption of afferent flow. It thus appears that a soluble and/or cellular component(s) of afferent lymph regulates the expression of GlyCAM-1 mRNA and the resultant HEV adhesiveness for lymphocytes.

Animals↗
PubMed1993

An investigation into the role of reactive oxygen species in the mechanism of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxicity using neuronal cell lines.

The study of oxygen radical generation and effects during 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) metabolism was undertaken in an in vitro test system. Three neurochemically discrete neuronal cell lines, B50 (cholinergic) and B65 rat cell lines and SKNSH human neuroblastoma (both catecholaminergic), were exposed to MPTP (0-200 microM). Parallel experiments were performed using reagent H2O2, an intermediate which may be generated during MPTP metabolism, to determine whether MPTP and H2O2 had any selectivity of toxicity and whether the mechanisms of cell death were similar. MPTP toxicity was shown to be reduced by monoamine oxidase B inhibitors, pargyline (P < 0.01) and selegiline (P < 0.05), indicating that toxicity was due to metabolism of MPTP rather than the parent compound. Cytotoxicity was also decreased in the presence of antioxidants, most notably in the presence of superoxide dismutase and catalase together (P < 0.01), suggesting that reactive oxygen species (ROS) play a role in MPTP-induced cell death. Attempts to determine the intracellular target for oxidative attack did not identify significant levels of lipid peroxidation products, but did demonstrate nucleoid expansion, possibly the result of double stranded DNA breaks induced by ROS.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1993

Overexpression of p53 in Hodgkin's disease: lack of correlation with Epstein-Barr virus infection.

Recent work has shown that p53 gene mutations are frequently found in Epstein-Barr virus (EBV)-positive and EBV-negative cases of Burkitt's lymphoma but not in EBV-associated undifferentiated nasopharyngeal carcinomas (NPCs). Similar viral gene expression patterns are observed in undifferentiated NPCs and in EBV-positive cases of Hodgkin's disease (HD), suggesting that the contribution of the virus to the pathogenesis of these malignancies may also be similar. We have analysed 116 cases of HD for EBV association and for immunohistologically detectable overexpression of p53. p53 overexpression was detected in the tumour cell population of 37 (32 per cent) of the cases. Fifteen cases showed p53-specific labelling of more than 40 per cent of tumour cells; in six of these, virtually all tumour cells were stained. In eight cases, between 5 and 40 per cent of tumour cells were labelled, and in another 14 cases, less than 5 per cent of tumour cells expressed detectable amounts of p53. EBV-positive HD cases were found in all groups with different levels of p53 overexpression as well as amongst p53-negative cases. While a more detailed analysis of the p53 gene in HD is required, these data show that overexpression of p53 in HD is heterogeneous and that there is no simple correlation between EBV infection and p53 overexpression.

Gene Expression↗
PubMed1993

An analysis of the diversity of Haemophilus parainfluenzae in the adult human respiratory tract by genomic DNA fingerprinting.

A method for typing Haemophilus species is described, based on the analysis of genomic DNA from Haemophilus parainfluenzae. The DNA was extracted by a rapid method and digested with the restriction enzyme BamHI to provide a characteristic 'fingerprint'. The pattern of fragments in the ranges 1-1.6 kb, 1.6-2 kb and 2-3 kb were used to produce a numerical profile of each isolate. In total 97 isolates were examined; 88 from throat swab material isolated from the 15 members of a British Antarctic Survey base and 9 type strains. Seventy-two of the 88 antarctic isolates were H. parainfluenzae and were found to be very diverse, comprising 41 identifiable strains with up to 5 strains being isolated from a single throat swab sample. There was evidence for both carriage and transmission within the isolated community. The technique provided a highly discriminatory method for characterizing Haemophilus strains which is suitable for epidemiological studies.

Adult↗
PubMed1993

Heterosexually acquired human immunodeficiency virus infection and the United States blood supply: considerations for screening of potential blood donors. HIV Blood Donor Study Group.

The impact of heterosexual transmission of the human immunodeficiency virus (HIV) on the United States blood supply was assessed, and deferral criteria that may exclude potential donors who are at high risk for heterosexually acquired HIV infection were evaluated. Interviews were conducted with 508 HIV-seropositive blood donors from May 1, 1988, to August 31, 1989 (Phase 1), and with 472 donors from January 1, 1990, to May 31, 1991 (Phase 2), at 20 blood centers. From Phase 1 to Phase 2, the overall HIV prevalence decreased from 0.021 to 0.018 percent (p < 0.001). HIV risk factors among HIV-1-seropositive donors were similar during both study phases. Eleven percent of the men and 56 percent of the women reported as their only risk that they had a heterosexual partner who was at increased risk for HIV or was known to have HIV. These percentages were similar during both study periods. During Phase 2, 13 percent of the men and 17 percent of the women with heterosexual transmission risk had a positive serologic test for syphilis, hepatitis B core antibody, or hepatitis C antibody. Among HIV-1-seropositive donors reporting heterosexual risk, the median numbers of previous-year and lifetime sex partners for men were 2 and 30, respectively; for women, those numbers were 1 and 7, respectively. Thirty-one percent of the men and 6 percent of the women reporting heterosexual transmission risk also reported having had syphilis or gonorrhea within 3 years of donation. It is concluded that the impact of heterosexual transmission of HIV infection on transfusion safety is not worsening at this time.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Banks↗
PubMed1993

Acute chest syndrome in sickle cell anaemia.

A patient suffering from sickle cell anaemia who presented with the acute chest syndrome is described. The syndrome is reported to be one of the commonest causes of death in adults suffering from sickle cell disease. As it is difficult at presentation to distinguish the syndrome from infection, it is usual to give treatment appropriate for both. Early exchange transfusion is thought to limit further damage from sickling and offers the best hope of recovery.

Acute Disease↗
PubMed1993

Group G streptococcal osteomyelitis of the spine.

Two elderly men, one with definite and one with probable malignancy, presented with severe back pain. Both had osteomyelitis of the lumbar spine due to Group G streptococci which responded to chemotherapy.

Aged↗
PubMed1993

Cardiac dysrhythmias associated with central nervous system dysfunction.

Intracranial pathology is frequently associated with cardiac dysrhythmias, which are sometimes lethal. Stroke, subarachnoid hemorrhage, seizures and head trauma with or without increased intracranial pressure are observed to be accompanied by myocardial damage and by ECG abnormalities, including T-wave changes, shortened P-R interval, prolonged Q-T interval, premature ventricular contractions, ventricular ectopy, sinus bradycardia, ventricular and supraventricular tachycardias. Derangements of autonomic function have been shown to be responsible for these disturbances of rate, rhythm and conduction. The autonomic nervous system receives neural input from various parts of the cerebral cortex, the hypothalamus and the brainstem which are extensively interconnected. Although unequivocal data supporting associations between specific neuropathological conditions or damage to specific structures and the observed dysrhythmias do not exist, some evidence for laterality of function does exist in humans. Tachycardia and pressor responses are more common after stimulation of the right insular cortex and after experimental stimulation of the left vagus which innervates the atrioventricular node and the cardiac conduction system. Bradycardia seems to be more common after stimulation of the left insular cortex or the right vagus nerve which innervate the sinoatrial node.

Arrhythmias, Cardiac↗