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Biomedical subjects

C Smith

Publications and source records attributed to C Smith.

At least 721 records · Page 40Linked to original sources
PubMed1990

Sexual abuse in a national survey of adult men and women: prevalence, characteristics, and risk factors.

This paper reports on the first national survey of adults concerning a history of childhood sexual abuse. Victimization was reported by 27% of the women and 16% of the men. Higher rates of abuse were found among men who grew up in unhappy families, lived for some period with only their mothers, who were currently residing in the West and who came from English or Scandinavian heritage. Higher rates of abuse were found among women who grew up in unhappy families, lived for some period without one of their natural parents, received inadequate sex education, were currently residing in the West or who were born after 1925.

Adolescent↗
PubMed1990

Characterization of heteromyeloma fusion partners which promote the outgrowth of porcine hybridomas.

Production of porcine monoclonal antibodies for use in research and immunotherapy has been hampered by the lack of suitable fusion partners which promote high efficiencies of hybridoma out-growth and immunoglobulin synthesis. To overcome these obstacles, five heteromyeloma fusion partners (HM-1,2,3,4 and 5) were constructed by successively fusing porcine lymphocytes with murine myeloma cells or murine x bovine heteromyeloma cells. Following section of hypoxanthine/aminopterin/thymidine (HAT)-sensitive mutants, karyotypes, growth rates and surface phenotypes of the heteromyelomas were determined. Karyotyping revealed an increase in the mean number of chromosomes present in HM-1,4 and 5 cells. Peak doubling times of the parental and HM cells ranged between 12.2 and 17.4 h. Uisng flow microfluorimetry and monoclonal antibodies specific for class I/II major histocompatability antigens, it was determined that the surface phenotype of HM-1,2,3,4 and 5 resembled that of the parental murine X63 myeloma cells. HM 1,2,3,4 and 5 were evaluated for their abilities to serve as fusion partners. Highest percentages of hybrid outgrowth (37%) and immunoglobulin synthesis (52%) were observed when HM-1 was fused with procine lymphocytes. When cloned, percentage of outgrowth and immunoglobulin synthesis increased if HM-1 and HM-2 were used as fusion partners. Cryopreservation of HM-1 and HM-2 did not adversely affect their abilities to promote hybrid outgrowth or immunoglobulin synthesis. During the first week following fusion of porcine lymphocytes with heteromyelomas, murine thymocytes were found to be essential for survival of the nascent hybrids. To confirm that immunoglobulin secreted by hybridomas was of porcine and not murine or bovine origin, culture supernates were subjected to SDS gel electrophoresis, electroblotted and identified. using species-specific isotyping reagents. Two of four cell lines tested secreted porcine light chains and one of four cell lines secreted whole IgM molecules. This paper is the first to describe porcine heteromyelomas for use as fusion partners. Similar to findings of human and bovine studies, our data suggest that heteromyeloma fusion partners perform better than rodent myelomas for creating hybridomas synthesizing porcine immunoglobulin.

Animals↗
PubMed1990

Reduced tracheal growth after reconstruction with pericardium.

Four groups of piglets were used to test the use of pericardium and periosteum as free grafts in the repair of full thickness cervical tracheal defects. Pericardium provided an airtight, rapidly healing graft, but did not give sufficient structural rigidity to prevent narrowing and growth failure at the graft site. Composite grafts of pericardium and periosteum were also unsatisfactory, in that the periosteum failed to produce enough bone to prevent collapse of the graft. Since previous studies have shown that periosteal grafts result in good bone formation when applied alone or as an extramucosal support, it is concluded that the osteogenic potential is dependent on the available blood supply and speed of revascularization. It appears that the presence of pericardium in the composite grafts may have inhibited this property.

Animals↗
PubMed1990

Developmental outcome of neonates treated with extracorporeal membrane oxygenation.

The leading cause of death in the neonatal period is respiratory failure, and extracorporeal membrane oxygenation (ECMO) is an effective means of improving survival in select patients. Only neonates with severe hypoxia and acidosis are treated with ECMO. To determine the developmental outcome of the neonates we supported with ECMO, we reviewed the records of all our patients who are at least 6 months of age. The results of follow-up assessment were available for 57 patients and growth parameters were available for 43 patients. Examinations were done at 6 to 48 months (mean, 22.1). Growth parameters showed that 14% of the patients were below the tenth percentile for height and weight while 16.3% were below the tenth percentile for head circumference. Twenty-four patients were evaluated using the Bayley Scales of Infant Development consisting of a Mental Developmental Index (MDI) and a Psychomotor Developmental Index (PDI). Normal scores (greater than 84) were obtained in 75% on the MDI and in 88% on the PDI. Only two patients (8%) scored less than 85 on both portions. Twelve patients were evaluated using the McCarthy Scales of Children's Abilities. The mean score was 95 and nine patients (75%) had scores greater than 85. The Gessell was used to evaluate six patients and five were normal. The Denver Developmental Screening Test was used to evaluate 23 patients and all passed. The results of neurologic examination were documented in 57 patients. One patient had severe spastic quadriplegia with cerebral palsy. The neurological examination was normal in the other patients. Only one of 57 patients is profoundly delayed (2%) and 45 (79%) are normal.(ABSTRACT TRUNCATED AT 250 WORDS)

Child Development↗
PubMed1990

Klebsiella pneumoniae bacteraemia at an urban general hospital.

Of 47 patients with Klebsiella pneumoniae bacteraemia admitted to the Hillbrow Hospital, Johannesburg during a period of 18 months, 31 were males and 16 were females. Features predisposing to illness were found in 89.4% patients, chronic alcoholism, neoplastic disease and diabetes mellitus being the most common. Twenty-five infections were acquired in hospital and 22 in the community. Most patients (59.6%) had pneumonia. All isolates of K. pneumoniae were resistant to ampicillin (100%); several (42.6%) were resistant to other antibiotics also. The overall mortality rate was 55.3%. A higher mean initial blood pressure and lower concentrations of serum urea and bilirubin were found in survivors. None of the 28 patients, surviving more than 48 h who received combined therapy with an aminoglycoside and a beta-lactam antibiotic (to which the organism was susceptible) died. Among the remaining patients treated with either an appropriate beta-lactam agent alone, an appropriate aminoglycoside alone or ciprofloxacin the combined mortality rate was 83.3% (P = 0.007).

Adolescent↗
PubMed1990

Antifolate and antibacterial activities of 5-substituted 2,4-diaminoquinazolines.

A series of 5-substituted 2,4-diaminoquinazolines (3) has been synthesized and evaluated as inhibitors of the enzyme dihydrofolate reductase (DHFR) from both bacterial and mammalian sources. The best compounds (e.g. 53) show good activity against Escherichia coli DHFR, but there is no significant selectivity for the bacterial over the mammalian enzyme. The structure-activity relationships for enzyme inhibition appear to be complex and not amenable to simple analysis; a hypothesis to explain the observed qualitative structure-activity relationships is proposed. The inhibitory activities of the compounds against the growth of intact bacterial cells in vitro closely parallel those for the inhibition of the isolated bacterial enzymes, suggesting that their antifolate action is responsible for their antibacterial effects. Five of the compounds were tested for their ability to cure a systemic E. coli infection in the mouse, but they showed no therapeutic effects at their maximum tolerated doses.

Animals↗
PubMed1990

High-dose cytosine arabinoside plus etoposide as initial treatment for acute myeloid leukaemia: a single centre study.

In a single centre, 52 newly diagnosed patients with acute myeloid leukemia (AML) under the age of 56 years received induction chemotherapy commencing with high-dose cytosine arabinoside (Ara-C) and etoposide (Protocol BF11), followed by Ara-C, 6 thioguanine (6TG). A total of 67% of patients entered remission using these drugs. An anthracycline was added for those patients not in remission. The overall remission rate (CR) was 86.5% (45/52), with a minimum follow-up of 90 days. Patients are hospitalised for relatively short periods, and consequently require less blood product and antibiotic support. Patients in continuing first remission following induction with Ara-C and etoposide are similar in number to those in continuing first remission who initially received an anthracycline. This would imply that the efficiency of Ara-C and etoposide in inducing long-term disease-term survival is comparable with anthracycline-containing regimens. We conclude that high-dose Ara-C and etoposide used in the first induction cycle for treating AML have good antileukaemic effect with acceptable toxicity.

Adolescent↗
PubMed1990

Inactivation of heparin during extracorporeal circulation in infants.

Heparin anticoagulation is necessary to prevent clotting during procedures involving the extracorporeal circulation of blood. Our preliminary observations suggested that heparin was inactivated in the extracorporeal circuit during extracorporeal membrane oxygenation. We tested this hypothesis by comparing heparin pharmacokinetics in five infants during extracorporeal circulation with kinetics, respectively determined in each patient and in the isolated circuit immediately after discontinuation of the procedure. Heparin clearance was 1.6 +/- 0.5 ml/kg/min in the patient and 2.1 +/- 0.8 ml/kg/min in the separated circuit. In each patient, the total of heparin clearances in the patient and circuit, 3.7 +/- 1.0 ml/kg/min, was virtually identical with the heparin clearance during the procedure, 3.8 +/- 1.9 ml/kg/min (r = 0.94, p less than 0.01). We conclude that more than one half of the heparin administered to infants during extracorporeal membrane oxygenation is eliminated by the extracorporeal circuit itself or by blood components in the circuit. These data explain the relatively large heparin doses needed to maintain anticoagulation in infants during extracorporeal circulation. In light of these findings, a reexamination of the normal mechanisms of elimination of heparin activity appears to be warranted.

Blood Coagulation↗
PubMed1990

In vivo 31phosphorus spectroscopy during transient cerebral ischaemia in the gerbil.

The depletion of the high energy phosphates; phosphocreatine and ATP, during cerebral ischaemia disrupts normal cellular function and can lead to cerebral infarction. Using in vivo nuclear magnetic resonance spectroscopy, the metabolic effects of the gerbil model of transient bilateral carotid artery occlusion were quantified. By examining the changes in the inorganic phosphate (Pi), phosphocreatine (PCr) and beta-ATP peaks, the PCr/Pi ratio, the PCr/beta-ATP ratio and intracellular pH (pHi) before, during and after an ischaemic insult were calculated. Preischaemic values for these parameters were: PCr/Pi = 2.466 +/- 0.130, PCr/beta-ATP = 1.691 +/- 0.053, pHi = 7.112 +/- 0.021. By the end of 20 min of global ischaemia, the PCr and beta-ATP peaks fell to levels similar to background in most animals. Calculated values were: PCr/Pi = 0.488 +/- 0.126, PCr/beta-ATP = 1.833 +/- 0.179, pHi = 6.551 +/- 0.258. With reperfusion, PCr/Pi increased rapidly back towards preischaemic levels but pHi improvement was delayed 10 min after that of PCr/Pi. By 1 h of reperfusion, both PCr/Pi and pHi were statistically equivalent to preischaemic values. During ischaemia, ATP was lost more rapidly than the storage form, PCr, but recovery of both was parallel. This suggested an intact ability to store such energy. These data indicate that the gerbil brain recovers normal high energy phosphate levels within an hour following a 20 min ischaemic insult, but that initial reperfusion does not immediately correct intracellular acidosis. Such a delay may prove a useful marker of those animals with more severe ischaemic injury.

Adenosine Triphosphate↗
PubMed1990

Complacency, risk perception and the problem of HIV education.

Many public surveys on the issue of HIV and AIDS have concentrated on the relationship between attitudes and knowledge. Often this relationship has been found wanting or at most tenuous. A recent survey of 1,002 people in Wales has supported these earlier findings, but found additionally that discriminatory and complacent attitudes on AIDS or towards people with the 'AIDS virus' are held by a significant proportion of the population. The survey also discovered that people correctly perceive the risk of HIV infection as being minimal. Depending on the question 17%-65% of the sample expressed discriminatory attitudes towards people that have the 'AIDS virus'. There was also no marked change over previous surveys in the degree of complacency surrounding AIDS. Younger people (aged (15-34) considered themselves to be more at risk of infection with the 'AIDS virus' but overall the perceived risk of infection was low. A sustained low key education programme in a variety of settings and independent of perceived risk is necessary to combat prejudice and complacency.

Adolescent↗
PubMed1990

Retrovirus-mediated insertional mutagenesis: phagemid rescue of flanking DNA by selecting plasmid ori.

A method for screening recombinant lambda libraries was devised to select phage containing genomic regions containing provirus insertions of retroviruses that carry the kanamycin and G418 resistance factor neo and the origin of replication derived from pBR322 (oripBR). Such recombinants are phagemids, able to replicate as bacteriophages or as plasmids under lambda repressor control. lambda repressor was cloned into a plasmid derived from pSC101 that is compatible with pBR322-derived phagemids. A strain carrying this plasmid may be used to select phagemids derived from a single proviral insertion with 100% efficiency from complex recombinant libraries. Homologous recombination between proviral long terminal repeats was observed at a rate of 10(-4)/plaque-forming unit in recABC+ strains. Despite this frequency, intact phagemids are easily recovered as phage after temperature shift to 42 degrees C. Since oripBR itself is a selectable marker in this system, the method could be applied to recover any sequence carrying the ori sequence from pBR322.

Bacteriophage lambda↗
PubMed1990

Whole blood activated clotting time in infants during extracorporeal membrane oxygenation.

Bleeding complications are the principal cause of morbidity and mortality in infants treated with extracorporeal membrane oxygenation (ECMO). The whole blood activated clotting time (ACT) test is used universally to monitor heparin therapy during this procedure. To enhance our understanding of this test and improve our management of anticoagulation, we studied the relationship between the ACT and blood heparin concentration in nine infants during ECMO. The activated clotting time correlated with the simultaneously determined heparin concentration (r = .55, p less than .001 for all patients samples; r = .92, p less than .001 for mean patients values). Within the range of values found in our patients, platelet count, fibrinogen, and fibrin degradation products did not affect the ACT-heparin concentration relationship. However, the interpretation of an individual ACT result was limited by its low precision: the mean difference of duplicate determinations was 9.2%, and the estimation of heparin concentration by a single ACT had a coefficient of variation of 32%. Two commercially available techniques using different activators gave results that differed numerically but correlated well with each other. Both provided similar precision in the estimation of heparin concentration. The ACT is a low cost, bedside test whose accuracy and precision allow the achievement of target heparin concentrations required in infants during ECMO. Multiple determinations, either in duplicate or serially, are needed to achieve satisfactory precision. These data will be useful in designing future studies to determine the optimal serum heparin concentration to provide adequate anticoagulation, but avoid bleeding complications.

Blood Coagulation Tests↗
PubMed1990

Public opinion on alcohol policies.

In recent years leading authorities and organizations have been recommending policies to combat alcohol abuse. These policies range from restrictions on availability to curbs on drinking and driving. However, the policies have not been presented in any priority order, nor is it clear how acceptable they will be to the general public. This report sets out public opinion on 21 key policies and looks at recent changes in public support in this area. It shows that there are a wide range of policies on alcohol which are well supported by the general public. It seems that the vast majority of both drinkers and non-drinkers would like to see more detailed labelling on alcoholic drinks, further action in the area of drinking and driving, the promotion of alternatives to alcohol in pubs, a levy on alcohol advertising, bans on the sale of alcohol at a variety of sports meetings, more alcohol education in schools and stricter enforcement of the laws on under-age drinking. In addition, the survey reveals greater public support for restrictions on the promotion of alcohol and the introduction of random breath testing, than had been found one year previously. It is suggested that these findings could be used for setting an agenda on the implementation of policies to reduce alcohol abuse.

Accidents, Traffic↗