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Biomedical subjects

S Bennett

Publications and source records attributed to S Bennett.

At least 181 records · Page 10Linked to original sources
PubMed1991

Age-dependent effects of sodium nitroprusside and dopamine in lambs.

Vasodilators and cardiotonic agents are frequently used in hypoxemic newborn infants with persistent pulmonary hypertension. We studied the effects of sodium nitroprusside and dopamine on hypoxia-induced pulmonary hypertension in seven newborn (0-3 d) and seven young (10-14 d) lambs under chloralose anesthesia. Pulmonary blood flow, pulmonary arterial pressure, systemic arterial pressure, and left atrial pressure were measured during the experimental states of hypoxia, hypoxia plus nitroprusside, and hypoxia plus both nitroprusside and dopamine. Pulmonary and systemic arterial pressure and cardiac output all decreased significantly when hypoxemic newborn lambs were given nitroprusside; in contrast, when hypoxemic young lambs were given nitroprusside, cardiac output did not change, whereas both pulmonary and systemic arterial pressure decreased significantly. Calculated pulmonary vascular resistance was unchanged in the newborn lambs but fell in the young lambs, implying that active pulmonary vasodilation by nitroprusside occurred only in the latter group. Systemic vascular resistance was not significantly affected by nitroprusside in either group. The addition of dopamine resulted in qualitatively similar changes in both groups of lambs, with increased pulmonary blood flow and no significant change in pulmonary or systemic arterial pressures. Maturation in vascular smooth muscle responsiveness to nitrovasodilators may explain the age-related differences that we found in lambs, and could also account for the variable clinical responses to vasodilators observed in hypoxemic human infants.

Age Factors↗
PubMed1991

A simplified general method for cluster-sample surveys of health in developing countries.

General guidelines are presented for the use of cluster-sample surveys for health surveys in developing countries. The emphasis is on methods which can be used by practitioners with little statistical expertise and no background in sampling. A simple self-weighting design is used, based on that used by the World Health Organization's Expanded Programme on Immunization (EPI). Topics covered include sample design, methods of random selection of areas and households, sample-size calculation and the estimation of proportions, ratios and means with standard errors appropriate to the design. Extensions are discussed, including stratification and multiple stages of selection. Particular attention is paid to allowing for the structure of the survey in estimating sample size, using the design effect and the rate of homogeneity. Guidance is given on possible values for these parameters. A spreadsheet is included for the calculation of standard errors.

Child↗
PubMed1991

Is childhood sexual abuse really increasing in prevalence? An analysis of the evidence.

One controversy regarding childhood sexual abuse is whether the increased rate of reported cases reflects a true increase in prevalence. In this report, data obtained in the 1970s and 1980s were compared with those of the 1940s. Using predetermined criteria for quality of information, commonality of definitions of childhood sexual abuse, and research design, the authors reviewed the Kinsey report published in 1953 and 19 prevalence studies reported in the last 10 years. Interrater reliability was .97 for each paper. In spite of differences in study designs and populations surveyed, where definitions of childhood sexual abuse were similar, the more recent studies with the strongest methodology reported prevalence figures similar to those of Kinsey in the 1940s, ie, 10% to 12% of girls younger than 14 years of age. Thus it would appear that increased reporting is due to changes in legislation and social climate rather than a true increase in prevalence. The absence of an increase in prevalence of childhood sexual abuse should not deter those interested in pursuing solid research in prevention and treatment because any childhood sexual abuse is too much.

Adolescent↗
PubMed1990

Cellular and humoral immune responses to Plasmodium falciparum gametocyte antigens in malaria-immune individuals. Limited response to the 48/45-kilodalton surface antigen does not appear to be due to MHC restriction.

We have examined immune responses to a cultured Plasmodium falciparum gametocyte lysate and to an affinity-purified preparation of the 48/45-kDa gamete surface Ag in a group of 30 malaria immune individuals and in 24 Europeans with no previous exposure to malaria. Cellular responses were assessed in vitro by lymphoproliferation and production of IFN-gamma; antigamete antibodies were detected by immunofluorescence, Western blotting, and competitive ELISA. Cells from all the malaria immune donors responded to the gametocyte lysate in both assays while cells from nonimmune donors gave only weak proliferative responses. Antigamete antibodies were detected in the serum of all the immune donors but not in serum from nonimmunes. Nonimmune donors were completely unresponsive to the purified 48/45-kDa surface Ag while cells from 40% of immune donors responded by either proliferation or IFN-gamma production. Only 3 of 30 immune donors had detectable antibodies to the 48/45-kDa Ag. Class II HLA type was determined for 27 of the immune donors but no relationship between HLA-DR or -DQ and responsiveness to the 48/45-kDa Ag was discerned. The possible reasons for limited recognition of this gamete surface Ag are discussed.

Animals↗
PubMed1990

Persistence of leptospiral agglutinins in Trinidadian survey subjects.

Participants in a survey for leptospiral agglutinating antibodies undertaken in Trinidad, West Indies, in 1977-78, were further monitored for up to 5-and-a-half years. 52 individuals with a titre greater than or equal to 1:400 were matched for age, sex and occupation with seronegative subjects. They were re-bled twice (on average 2.38 and 4.84 years later), and changes of titre were noted. At the first follow-up, 78% of negative controls remained negative, and 22%, showed titre changes. Among the seropositive subjects, 47% showed a fall in titre, 38% showed no change, and in 15% the titre rose. New exposure rates between the original and first follow-up samples were 96/1,000 survey population per year in the controls, and 68/1,000 for the subjects with titres greater than or equal to 1:400. Between the first and second follow-up, 47% of the seropositive subjects lost titre, 40% showed no change, and 13% showed a rise in titre. These data demonstrate that although antibody titres may be maintained for a few years at the same level, or show a loss as is usually expected, about 8.3% of individuals in Trinidad may be infected/reinfected per year. The infection/reinfection rate is an important factor in the epidemiology of leptospirosis.

Adolescent↗
PubMed1990

The comparison of trends in perinatal mortality in small areas.

Year to year changes in perinatal mortality rates for small populations are difficult to interpret. Because local rates are based on small numbers of events, they are subject to apparently large fluctuations. A technique for analysing trends in mortality, for detecting changes in trends and comparing variations in trends between areas is described. It is illustrated by an analysis of perinatal mortality rates for Area Health Authorities in the West Midlands Region of England from 1974-1981, but the same techniques could be used to analyse trends at other times and in other places.

Birth Rate↗
PubMed1990

Surgical techniques of oocyte collection and embryo transfer.

In the decade since the birth of the first child conceived as a result of in vitro fertilization and embryo transfer much has been achieved in the field of assisted conception. Although in vitro fertilization (IVF) was successful first for the treatment of tubal disease, the indications for its use have now widened to include unexplained infertility, oligozoospermia, endometriosis and infertility due to immunological disorders. Gamete intrafallopian transfer (GIFT) and zygote intrafallopian transfer (ZIFT) are now used commonly for the treatment of couples where the woman has patent fallopian tubes. The huge increase in the demand for therapy using these techniques of assisted conception places considerable strain on the finances available for health care, and has led some to question the wisdom of such use of limited resources. To reduce the cost of treatment, and because repeated IVF-ET attempts may be necessary before achieving pregnancy, the initial laparoscopic approach for oocyte recovery has been largely replaced by ultrasound-guided techniques. Non-surgical embryo transfer techniques have changed little since originally described. However, where the tubes are patent, one-cell zygotes or cleavage stage embryos may be transferred into the fallopian tube (ZIFT and tubal embryo stage transfer respectively). On the other hand if the tubes are blocked, surgical embryo transfer (SET) may be performed. Most recently, some success has been achieved following the transfer of embryos into the fallopian tube by the technique of retrograde fallopian tube catheterisation.

Biopsy, Needle↗
PubMed1990

Postsurgical follow-up study of patients with severe polypoid degeneration.

This report summarizes our experiences with 23 women whose bilateral severe polypoid degeneration was managed surgically and who have been followed over a 2- to 7-year postoperative period. In our study group, polypoid degeneration did not reappear if the patient stopped smoking and practiced healthy vocal hygiene. About 25% of those who continued to smoke after surgery evidenced return of the disease, usually within 2 to 3 years. Reappearance of polypoid degeneration appeared most strongly related to the smoking variable alone or in combination with vocal abuse and/or medications that can cause edema. Neither vocal abuse nor medications appeared to be primary causal factors. The return of polypoid degeneration, in its earliest stages, was detected first via laryngeal examination.

Adult↗
PubMed1990

Identifying clinical nursing research priorities.

This paper describes a project conducted by a nursing research committee to identify and prioritize nursing research questions or topics that are most significant to the welfare of patients at a Southern university hospital. Ninety-seven nurses representing clinical staff, administration, and education were invited to participate in three rounds using the Delphi survey technique. Group consensus was reached on priority areas for nursing research at this particular institution. The purpose of this article is to outline the process of developing the project and discuss recommendations resulting from the survey.

Clinical Nursing Research↗
PubMed1990

Evaluation of a primary health care programme in The Gambia. I. The impact of trained traditional birth attendants on the outcome of pregnancy.

In 1983 a primary health care (PHC) programme was introduced into the Farafenni area of The Gambia; an important component of this programme was the identification and training of a traditional birth attendant (TBA) in each village with a population of 400 or greater. The outcome of pregnancy has been documented among women resident in 15 villages which joined the PHC programme and in 26 which were too small to do so, for 1 year before and for 3 years after the start of the programme. In PHC villages 65% of women were assisted at delivery by a trained TBA during the post-implementation period and the proportion of women who delivered in a hospital or health centre increased. Both maternal and neonatal death rates fell in PHC villages during the post-intervention period, declining to about half the levels recorded during pre-intervention surveys during the last year of the study. In non-PHC villages there was also a fall in the maternal death rate but little change in the neonatal death rate. Trained traditional birth attendants probably played some part in improving the outcome of pregnancy in the Farafenni area but other factors, such as improvements in transport, may also have contributed.

Adolescent↗
PubMed1989

An estimate of diabetes prevalence from a national population sample: a male excess.

We report the prevalence of diabetes in a population sample of 10,083 persons who were aged 25 to 64 years in eight city centres. One hundred and sixty-nine persons were known to have diabetes and 48 persons were newly-discovered to have diabetes on the basis of fasting hyperglycaemia (plasma glucose level, equal to or greater than 7.8 mmol/L). Type-1 diabetes was identified by clinical criteria and accounted for 19% of cases of known diabetes, but this proportion ranged from 67% of persons with known diabetes in the age-group of 25-29 years, to between 9% and 15% in the age-groups of persons who were 50 years of age and over. For both known and newly-discovered cases, persons with type-2 diabetes showed a significant male preponderance, which suggests that an environmental factor is operating preferentially on male subjects to cause this form of diabetes. The results of the present study, when taken with those of other recent prevalence studies, enable an approximate estimate of numbers of persons with diabetes in Australia. Approximately 250,000 persons have diagnosed diabetes, of whom 40,000 persons have type-1 diabetes, including 7000 persons who are less than 25 years of age. The number of persons with undiagnosed diabetes who could be identified on the basis of fasting hyperglycaemia is estimated to be 75,000; an additional 150,000 persons would be diagnosed to have diabetes if they were to undergo glucose tolerance tests. This study gave prevalence rates for known diabetes in Australia in 1984 of 1.6% at all ages and 2.4% for adults who were 21 years of age and older; additionally, the estimated prevalence rates for undiagnosed diabetes were 1.4% for all ages and 2.2% for adults.

Adult↗
PubMed1989

Sporozoite antibodies and malaria in children in a rural area of The Gambia.

Sporozoite antibody levels were measured in a group of children aged one to nine years resident in a rural area of The Gambia, using an ELISA to the repeat peptide (NANP)40. The prevalence and titre of antibodies varied with age but not with sex or ethnic group. Significant variations in prevalence were recorded within a group of adjacent villages. Children who were seropositive at the beginning of the dry season had higher spleen and parasite rates both at this time and at the end of the subsequent rainy season than did seronegative children, suggesting that they were exposed more frequently to infection. However, seropositive children had fewer episodes of fever accompanied by high levels of parasitaemia than did seronegative children, suggesting that they had a greater degree of clinical immunity. No differences were found in seroprevalence rates or in mean antibody titres between children who slept under conventional or Permethrin treated bed nets and those who did not, even though bed nets significantly reduced the number of bites by vector mosquitoes.

Age Factors↗
PubMed1989

Evaluation of factors influencing vaccine uptake in Mozambique.

A pulse immunization project was started in Mozambique to compensate for the decrease in routine immunization caused by destabilization. A study was conducted to evaluate the project and identify determinants of vaccination in urban and rural areas of Mozambique. Vaccine coverage based on a documented record, the 'Road to Health' card, was 53% in urban and 60% in rural project areas, and 12% higher if a verbal history of vaccination was considered. A further 17% of children would have received effective vaccination if the correct schedule had been followed for all vaccines given and all preventive health services contacts had been used for vaccination. Factors relating to the individual mother and child and factors relating to the clusters were investigated for their association with vaccine uptake. Those which showed a strong negative association included vaccination on offer at the nearest vaccination post for only a small number of days per week; cancellation of an outreach session; knowing a child with a post-vaccination abscess; child born at home; at least five children in the family; mother's inability to speak Portuguese and her inability to name at least two target diseases. Improving the supervision of health services and immunizing at least three days per week at permanent immunization clinic sites may be the most important measures to improve coverage further.

Adult↗
PubMed1989

Phonatory characteristics following surgical treatment of severe polypoid degeneration.

This paper summarizes the results of our research into the efficacy of phonosurgery. Our study group consisted of 25 women whose severe, bilateral polypoid degeneration was managed surgically by one of the following methods: Hirano's technique, mechanical stripping, or CO2 laser enucleation. We found that all three procedures improved the voice. Surgery increased the average speaking fundamental frequency level substantially and improved the phonational range. Listeners' judgments about the appropriateness of vocal pitch and severity of hoarseness also changed positively following surgery. No one method was clearly better than another in improving the voice. However, patients treated using Hirano's method experienced the most rapid return of functional voice use, probably because the procedure is less traumatic and promotes more rapid healing than mechanical stripping or laser removal.

Female↗
PubMed1989

Arterial bullet embolism.

We report a case of an arterial bullet embolus and compare it with other cases found in the literature. A 27-year-old white male sustained a .22 caliber gunshot wound that penetrated the abdominal aorta and traveled within the arterial system to occlude the left superficial femoral artery. The case was typical in that projectiles that embolize within the vascular system originate as a low kinetic energy missile injury of the trunk. Atypically, the patient developed ischemic changes from the embolus immediately. After direct aorta repair and immediate transverse arteriotomy bullet removal, the patient recovered fully.

Adult↗
PubMed1988

Alternative promoters and exons, somatic mutation and deregulation of the Bcl-2-Ig fusion gene in lymphoma.

The most common translocation in human lymphoma, the t(14;18)(q32;q21), generates heterogeneous 4.2-7.2 kb Bcl-2-immunoglobulin (Ig) chimeric mRNAs resulting from alternative Bcl-2 5' exons and varied Ig 3' untranslated regions (UT). The normal human Bcl-2 gene has a three exon structure with an untranslated first exon, a facultative 220 bp intron I, but an enormous 370 kb intron II. S1 protection and primer extension analysis defined initiation sites in exon II associated with classic promoter elements and a decanucleotide (ATG-CAAAGCA) homologous with Ig variable region enhancers. Multiple initiation sites were also found in a GC-rich region with Sp1 binding motifs in exon I. Most t(14;18) breakpoints cluster within the 3' UT of Bcl-2 implicating that event in gene deregulation. The Bcl-2 gene introduced into the Ig constant (C gamma) locus of SU-DHL-6 displayed somatic mutation. While Bcl-2--Ig mRNAs demonstrated an unaltered 2.5 h half-life, the Bcl-2--Ig gene revealed an inappropriately high rate of transcription for a mature B-cell. This indicates the translocated Bcl-2 allele has escaped normal control mechanisms.

Amino Acid Sequence↗