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Biomedical subjects

R Hayes

Publications and source records attributed to R Hayes.

At least 109 records · Page 6Linked to original sources
PubMed1993

HIV, breast-feeding and under-5 mortality: modelling the impact of policy decisions for or against breast-feeding.

A computer model was developed to assess the impact on under-5 child mortality of breast-feeding practices in developing countries in the context of HIV infection. The model was used to estimate the effect on mortality of cessation of breast-feeding among mothers HIV-positive and mothers HIV-negative at birth, for both urban and rural settings. Using parameter values for a hypothetical East African country, cessation of breast-feeding in urban areas was predicted to result in increases in under-5 mortality of 108% for children of mothers HIV-negative at birth, and 27% for those HIV-positive at birth, with slightly larger increases in rural areas, suggesting that breast-feeding should continue to be promoted. A sensitivity analysis was conducted to identify critical values of key variables for which a review of policies encouraging breast-feeding is indicated. This showed that, even under extreme assumptions, cessation of breast-feeding among mothers HIV-negative at birth (but at risk of acquiring HIV during the lactation period) would increase under-5 mortality. For mothers HIV-positive at birth, the key variables are the additional risk of vertical transmission attributable to breast-feeding, the under-5 mortality rate (U5MR) in breast-fed children, and the relative risk of mortality in non-breast-fed compared to breast-fed children. Depending on the values of these key variables, there may be some urban populations with low U5MR in which the positive and negative effects on under-5 mortality of a policy change are finely balanced. However, no change in policy should be made in these areas until more precise information is available on the key variables, and the many adverse consequences of such a change have been fully explored.

Breast Feeding↗
PubMed1993

Semisynthetic sphingolipids prevent protein kinase C translocation and neuronal damage in the perifocal area following a photochemically induced thrombotic brain cortical lesion.

A vascular thrombotic lesion localized to the rat sensorimotor cortex was produced following intravenous injection of the photosensitive dye rose bengal, and its activation with a small beam of high-intensity white light focused to the skull overlaying the sensorimotor cortex. In the sensorimotor cortex at various times after the triggering event, two contiguous brain regions with different degree(s) of neuronal damage can be distinguished: (1) a primary thrombotic ischemic core where the majority of cells are dead and (2) a penumbra region surrounding the core lesion in which a slower progressive neuronal degeneration is occurring. Importantly, in both brain regions the neuronal degeneration is associated with the activation and persistent translocation of protein kinase C (PKC) as indicated by an increase in 4-beta-3H-phorbol-12,13-dibutyrate (3H-PDBu) binding. Moreover, the demonstration that in the area penumbra the neuronal degeneration and the persistent translocation of PKC can be inhibited by a pretreatment with dizocilpine (i.e., MK-801) indicates that the dynamics of the progression of the neuronal degeneration are maintained by glutamate accumulating in the extraneuronal fluids. MK-801 additionally prevents the transcriptional activation of several immediate-early genes (IEGs) (e.g., c-fos) and their cognate third nuclear messenger (i.e., c-Fos) expression present in the hemisphere ipsilateral to the lesion. On the other hand, LIGA4 and LIGA20 derivatives of GM1 lysoganglioside reduce the membrane translocation of PKC and the neuronal damage in the penumbra area, but fail to change the increase of IEG expression in the cortex ipsilateral to the lesion.

Animals↗
PubMed1992

Cross-sectional survey of HIV infection among patients with tuberculosis in Nairobi, Kenya.

Evidence from many countries suggests an association of human immunodeficiency virus (HIV) infection and tuberculosis of major public health significance. In order to begin assessing the impact of HIV on tuberculosis in Kenya, we have determined the HIV-1 seroprevalence among tuberculosis patients and compared the clinical characteristics of tuberculosis in HIV-positive and HIV-negative patients in two cross-sectional studies at the Infectious Disease Hospital (IDH) and the Ngaira Avenue Chest Clinic (NACC), Nairobi, Kenya. The diagnosis in 92% of all patients with pulmonary tuberculosis was confirmed by culture. The remainder were diagnosed on histological, clinical or radiological grounds. HIV seroprevalence among tuberculosis patients at IDH was 26.5% (52/196) compared to 9.2% (18/195) at NACC (P less than 0.001). There was no association between numbers of streptomycin injections in the previous 5 years and HIV infection. Positive sputum smear rates in HIV-positive patients were slightly lower than in HIV-negative patients at both study sites (71% vs 83% at IDH and 73% vs 82% at NACC) but the difference was not significant. Only Mycobacterium tuberculosis was isolated. Miliary disease was not associated with HIV infection. Persistent diarrhoea, oral candidiasis, generalized itchy rash, herpes zoster and generalized lymphadenopathy were all associated with HIV infection, but 46% (95% CI:38-54%) of all HIV-positive patients had none of the clinical features listed in the WHO Clinical Criteria for the Diagnosis of AIDS, apart from fever, cough and weight loss. Stevens-Johnson Syndrome was reported in 7/52 (13%) patients with HIV infection, and in 4/144 (3%) patients without (RR 4.85, 95% CI: 1.45-15.88).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Comparison of methods of assessing 24-hour intraesophageal pH recordings in children.

Prolonged intraesophageal pH recording, an important test in the evaluation of children with suspected gastroesophageal reflux (GER) disease, may be performed and evaluated by markedly different methodologies. Twenty-four-hour intraesophageal pH recordings from 67 consecutive infants were evaluated by three scoring methods: early postprandial, late postprandial, and total recording. In addition, the scoring methods were evaluated for their ability to identify 20 infants with clinically defined GER-induced acute life-threatening events (ALTEs). There were significant positive correlations between each pair of scoring systems (early postprandial with late postprandial, early postprandial with total recording, and late postprandial with total recording). However, our data indicate that the three methods identify different groups of patients. The early and late postprandial methods disagreed in designating "normal" versus "abnormal" in approximately 20% of patients. The total recording method was more likely to label patients as normal than either of the other methods; it yielded normal results in approximately one half of patients abnormal by either the early or the late postprandial methods. Patients with GER-induced ALTEs were identified by the early postprandial method in 90% of cases, the late postprandial method in 95% of cases, and the total recording method in only 45% of cases. By applying three different scoring methods to the same 24-h intraesophageal pH recording, we demonstrated less-than-perfect correlation among the methods. Long-term follow-up is needed to determine if these differences are of clinical significance. We feel that effort should be directed toward standardizing the approach to intraesophageal pH monitoring in infants.

Esophagus↗
PubMed1992

The value of urine specimens in screening for male urethritis and its microbial aetiologies in Tanzania.

OBJECTIVE: To evaluate the first void urine (FVU) specimen in screening for urethritis and its microbial aetiologies in a male African population in which urinary schistosomiasis is also prevalent. PATIENTS AND METHODS: Two hundred and forty eight males aged 15-54 years provided FVU specimens: 55 patients from a clinic for sexually transmitted diseases (STD), 151 patients from a medical outpatient clinic and 42 villagers from an area of high endemicity for S haematobium. Specimens were tested for leucocyte esterase (LE) using a dipstick (Nephur-Test+Leuco, Boehringer-Mannheim France SA). Ova of S haematobium were sought in terminal urine samples from all subjects. For all STD patients, and all medical outpatients with a positive LE test, urine and urethral swabs were tested for Chlamydia trachomatis antigen, and urethral swabs were tested for Neisseria gonorrhoeae by gram stain and isolation. RESULTS: The prevalence of LE positivity was 38/41 in STD patients with urethral signs or symptoms (93%), 5/14 among other STD patients (36%), 21/151 among medical outpatients (15%) and 13/42 among villagers (31%). As a screening test for urethral infection (detection of gonorrhoea or chlamydia and/or > or = 5 polymorphs per high power field on gram stain) the LE test had a sensitivity of 94% and a specificity of 53% among STD patients. Of 24 STD patients with gonococcal or chlamydial infection, 23 had a positive LE test (96%). Among general medical outpatients, 12 of 22 with a positive LE test had either conventionally defined urethritis or gonococcal or chlamydial infection, giving a positive predictive value of 55% for the LE test in this group. Of 18 subjects in all groups with urinary schistosomiasis nine had a positive LE test (50%), although three of these also had gonorrhoea. Chlamydial antigen was detected in the FVU specimen of all six subjects in whom it was detected in a urethral swab, and in an additional three subjects in the outpatient group. CONCLUSIONS: The FVU, which is an easily collected and non-invasive specimen, can provide valuable information on the prevalence of urethritis and on its microbial aetiology among the general male population in African countries.

Adolescent↗
PubMed1992

Patient psychoeducation: the therapeutic use of knowledge for the mentally ill.

Psychoeducation has been used successfully with families of patients with psychiatric illness for over the past two decades. Modifying this model for use with mentally ill patients has demonstrated to both patients and staff the positive impact that knowledge can have on patients' functioning and attitudes. The model described has three objectives: (1) to impart information about psychiatric illness, medication and treatment regimens as a way of increasing patients' understanding, (2) to provide a forum which facilitates the integration of this information through group discussions with other patients and (3) to teach and model some specific management skills for patients as they deal with their illnesses.

Day Care, Medical↗
PubMed1991

Mortality among workers exposed to ethylene oxide.

BACKGROUND: Ethylene oxide is a sterilant gas that causes leukemia and other cancers in animals. Studies in Sweden have shown an excess of leukemia and stomach cancer in humans exposed to ethylene oxide, but other studies have generally failed to confirm these findings. METHODS: We conducted a study of mortality in 18,254 U.S. workers exposed to ethylene oxide at 14 plants producing sterilized medical supplies and spices. The subjects averaged 4.9 years of exposure to the gas and 16 years of follow-up. The exposure levels in recent years averaged 4.3 ppm (eight-hour time-weighted adjusted exposure) for sterilizer operators and 2.0 ppm for other workers. The levels in earlier years are likely to have been several times higher. Mortality in this cohort was compared with that in the general U.S. population. RESULTS: Overall there was no significant increase in mortality from any cause in the study cohort. The standardized mortality ratios (SMRs) were 0.97 for leukemia (95 percent confidence interval, 0.52 to 1.67; 13 deaths observed), 1.06 for all hematopoietic cancers (95 percent confidence interval, 0.75 to 1.47; 36 deaths), and 0.94 for stomach cancer (95 percent confidence interval, 0.45 to 1.70; 11 deaths). Analyses according to job category and according to the duration of exposure showed no excess in cancers, as compared with the rate in the general population, but there was a significant trend toward increased mortality with increasing lengths of time since the first exposure for all hematopoietic cancers. The rate of death from hematopoietic cancer (especially non-Hodgkin's lymphoma) was significantly increased among men (SMR, 1.55; 27 deaths). Mortality from leukemia in recent years (1985 through 1987) was significantly increased among men (SMR, 3.45; 5 deaths). CONCLUSIONS: For the entire cohort, there was no increase in mortality from hematopoietic cancer. There was a slight but significant increase among men, however. Among men and women combined, there was a trend toward an increased risk of death from hematopoietic cancer with increasing lengths of time since the first exposure to ethylene oxide.

Cohort Studies↗
PubMed1991

Acute inflammation of the breast--the role of breast ultrasound in diagnosis and management.

Twenty female patients aged between 24 and 69 years were referred for breast ultrasound (US) examination between June 1989 and June 1990, with clinical suspicion of a breast abscess. Six were currently lactating. Initial US examination confirmed the presence of an abscess collection in nine out of 20 patients. Seven of these subsequently had surgical incision and drainage. Two settled on medical treatment. No abscess was detected on initial US examination in the remaining 11 patients who were treated conservatively with oral antibiotics. One patient, who had markedly dilated ducts on her initial US examination, remained symptomatic. Follow-up US demonstrated a small fluid collection, which within 7 days developed into a large multiloculated abscess requiring surgical drainage. We feel that US is very useful in accurately demonstrating the presence or absence of an abscess collection in the acutely inflamed breast.

Abscess↗
PubMed1991

The mammographic parenchymal patterns of nulliparous women and women with a family history of breast cancer.

One-hundred-and-thirteen mammograms of nulliparous women and 44 mammograms of women with a family history of breast cancer were graded according to Wolfe's parenchymal pattern classification. These were compared to 437 mammograms of women without these risk factors. Mammograms were read by two independent observers in order to evaluate inter- and intra-observer variation. The interobserver variation was reduced from 17% to 5% by combining high risk patterns (P2 and DY) and low risk patterns (N1 and P1). A significantly higher proportion of high risk patterns was found in nulliparous women compared to parous women (P less than 0.01). The proportion of high risk patterns decreased significantly with the number of children (P less than 0.01). Women with a family history of breast cancer had almost the same parenchymal patterns as women without a family history. In conclusion, while nulliparity and family history are recognized risk factors for developing breast cancer, only nulliparity would appear to influence the mammographic parenchymal pattern. This probably reflects the different mechanism by which the two factors affect breast tissue.

Breast Neoplasms↗
PubMed1991

The mammographic parenchymal patterns of women on hormonal replacement therapy.

In this study 383 mammograms of women on hormone replacement therapy (HRT) for more than one year and 216 mammograms of women performed before HRT was started were examined to identify any mammographic features which are associated with a higher incidence of developing breast cancer according to Wolfe's criteria. There was no significant difference in the proportion of high and low risk parenchymal patterns as the duration of HRT increased. A significantly higher proportion of low risk patterns with ageing was observed in 216 women who had never been on HRT when compared to 194 mammograms of women who had been on HRT for more than 5 years. This difference becomes more obvious in women on HRT with less than three children compared to a similar group not taking HRT. Women who had not taken HRT appeared to undergo normal involutional changes which were reflected by an increase in the proportion of low risk patterns with increasing age. We may conclude from these findings that HRT appears to inhibit involutional processes within the breast and therefore this group have higher risk parenchymal patterns for a longer period of time and subsequently may have a higher risk of developing breast cancer.

Age Factors↗
PubMed1991

Evaluation of magnification and paddle compression techniques in the assessment of mammographic screening detected abnormalities.

Between February 1988 and December 1989, 8.6% of all women who presented to the South East London Breast Screening Centre for mammography were recalled for assessment. Magnification or paddle compression techniques were used in the assessment of 39% of these patients. The aim of the study was to evaluate the improvement in mammographic specificity provided by these 'special views'. Three hundred and thirty cases were reviewed. The basic mammograms were assessed both alone and together with the special views, and the mammographic findings were scored according to the index of suspicion for malignancy. Special views were felt to be helpful when they led to an increase in mammographic specificity. It was found that special views increased mammographic specificity in 50.8% of cases. Sixteen 'equivocal' diagnoses became 'normal' or 'benign' and 15 of these patients avoided surgical biopsy. Twelve 'equivocal' diagnoses became 'malignant', which helped surgical planning, and in all 12 cases, histology confirmed the diagnosis of malignancy. It is felt that 'special views' are necessary for the complete mammographic assessment of many screen-detected abnormalities.

Breast Diseases↗
PubMed1991

A technique to investigate the three-dimensional kinesiology of the human temporomandibular joint.

Previous kinesiological studies of the temporomandibular joint (TMJ) were based on the motion of only one or two selected points on the mandible (such as the lower central incisor, the mandibular condyle). In the present study, a technique was developed to measure, analyze, and describe the full three-dimensional kinematic characteristics of the TMJ during any mandibular activity. The technique was based on determination of the relative position between the mandible and the temporal bone from measurement of the location of points on light-weight frames rigidly attached through splints to the maxillary and mandibular teeth. An optoelectric kinematic data acquisition system has been used to record the location of these points. The results of the study indicate the following major advantages of this technique over previously reported kinesiological methods: (1) the technique provides a full description of the motion of the mandible with respect to the temporal bone, including all the six degrees of freedom associated with this motion; (2) the description of motion in terms of joint parameters enhances interpretation of the data by clinicians; (3) the motion of any point of interest on the mandible can be easily derived from the data and; (4) the system provides only negligible interference with the natural jaw motion of the subject. It does not require head fixation, does not alter or interfere with the natural occlusion, and its light weight causes only minimal (and negligible) loading of the mandible.

Calibration↗
PubMed1991

Risk factors for human immunodeficiency virus infection in 581 intravenous drug users, northeast Italy, 1984-1988. The AIDS and Related Syndromes Study Group.

Prevalence and risk factors for human immunodeficiency (HIV) virus infection were assessed in 581 heterosexual intravenous drug users (IVDUs), recruited from eight public drug assistance centres in the northeast of Italy, an area at low risk for AIDS. The overall seroprevalence for HIV antibody was rather high, 39% (95% confidence interval (CI): 35-43%). HIV prevalence had risen from 32% in 1984-1985 to 52% in 1987-1988. Thirty-three per cent of female and 41% of male IVDUs had antibodies to HIV (p = 0.07). Seropositivity rates showed a strong east-west geographical gradient (from 16% to 60%, p = 0.005): IVDUs living in the western part of the study area had a nearly sevenfold higher risk of infection (odds ratio (OR) = 6.9, 95% CI: 4.4-13.9) than those living in the eastern part. Sharing of drug injection equipment (OR = 3.6), duration of drug addiction (OR = 2.6), use of heroin in high-incidence cities (OR = 2.3), use of cocaine in addition to heroin (OR = 1.5) and history of prostitution (OR = 2.3) increased the risk of acquiring HIV infection. Over the study period, the ORs associated with area of residence decreased, whereas those associated with the use of heroin in high-incidence cities and with prostitution increased.

Adult↗
PubMed1991

Risk factors for HIV-2 infection in The Gambia.

A serosurvey was carried out to assess the prevalence of HIV infection in The Gambia and the importance of possible risk factors. The overall prevalence of HIV-2 infection among the 4228 adults studied was 1.7% while that of HIV-1 was 0.1%. The prevalence of HIV-2 was similar in both sexes but higher among those greater than 25 years of age and those who lived in two small towns along a main transport route. Among men, multivariate analysis showed prevalence of HIV-2 infection was significantly greater among those in the more affluent occupations, those without a secondary education and those with a history of urethral discharge. Among women, infection was more frequent in divorcees and widows and those who had been married several times. The prevalence was also higher in individuals born in Guinea-Bissau and in an ethnic group which originated there.

Adolescent↗
PubMed1991

The effects of ioxaglate 320, iohexol 350, and iopamidol 370 on erythrocyte aggregation.

The authors report a randomized, double-blind prospective trial comparing the effects of nonionic with ionic low-osmolar contrast media on erythrocyte aggregation. The study group comprised 40 consecutive patients with pathology necessitating selective angiography. Patients were examined using either ioxaglate 320, iohexol 350, or iopamidol 370. Erythrocyte aggregation was assessed both macroscopically and microscopically. Erythrocyte aggregation occurred more frequently in the iopamidol group (13 of 45 samples examined) than in the iohexol (4 of 46) or ioxaglate (5 of 51) groups (P = .002).

Adolescent↗