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Biomedical subjects

R Black

Publications and source records attributed to R Black.

At least 37 records · Page 2Linked to original sources
PubMed1998

Yearly colonoscopy, liver CT, and chest radiography do not influence 5-year survival of colorectal cancer patients.

BACKGROUND & AIMS: Guidelines on the type and frequency of follow-up of patients after curative surgery for colorectal cancer are unclear. The aim of this study was to determine the survival benefit of a planned follow-up program. METHODS: Three hundred twenty-five patients who underwent curative resection of colorectal cancer were prospectively randomized to either intensive or standard follow-up. After stratification according to Dukes' stage and site in the colon or rectum, patients were randomized to intensive follow-up of yearly colonoscopy, computerized tomography (CT) of the liver, and chest radiography and clinical review and simple screening vs. structured clinical review and simple screening tests only. RESULTS: On completion of 5-year follow-up, there was no significant difference in survival between the two groups. Yearly colonoscopy failed to detect any asymptomatic local recurrences. Only one asymptomatic curable metachronous colon tumor was detected. Liver CT resulted in earlier detection of hepatic metastases but did not increase the number of curative hepatectomies. Only 1 patient had an asymptomatic CT-detected liver metastasis, and another had an asymptomatic chest radiography-detected lung metastasis. Both had curative resections. CONCLUSIONS: Yearly colonoscopy, liver CT, and chest radiography will not improve survival from colorectal cancer when added to symptom and simple screening review.

Adult↗
PubMed1998

The efficacy and fetal-maternal cardiovascular effects of transdermal glyceryl trinitrate in the prophylaxis of pre-eclampsia and its complications: a randomized double-blind placebo-controlled trial.

OBJECTIVES: Pre-eclampsia continues to be a major cause of maternal and perinatal mortality. A disorder of the nitric oxide system is implicated in the pathogenesis of this condition and preliminary studies have suggested a possible therapeutic role for nitric oxide donors in women with established pre-eclampsia. The aim of this study was to determine whether pre-eclampsia and its complications could be prevented by the long-term use of nitric oxide donors in a group of women identified to be at risk on the basis of abnormal uterine artery Doppler measurements. STUDY DESIGN: We enrolled 40 healthy normotensive women at high risk of pre-eclampsia selected on the basis of abnormal uterine artery Doppler waveforms at 24-26 weeks of gestation. Women were randomly allocated to receive transdermal glyceryl trinitrate 5 mg-patches or equivalent placebo patches in a double-blind randomized study. The primary outcome measures were pre-eclampsia, fetal growth restriction, preterm delivery or small for gestational age/fetal growth restriction rates. Patches were worn daily from recruitment for 10 weeks or until delivery. RESULTS: The primary outcomes were not significantly different in the placebo compared to the glyceryl trinitrate group. However, survival analysis of adverse events with gestation in both groups showed a significantly reduced risk of an adverse event in the glyceryl trinitrate group (p = 0.004), equating to a 73% reduction in hazard. There was no difference in maternal systolic and diastolic blood pressure, mean uterine artery resistance index and fetal umbilical and middle cerebral artery pulsatility indices between the groups. CONCLUSIONS: Low-dose prophylactic transdermal glyceryl trinitrate commenced late in the second trimester did not reduce the incidence of pre-eclampsia, preterm delivery or fetal growth restriction, but may increase the likelihood of a complication-free pregnancy. Transdermal glyceryl trinitrate (5 mg/day) did not affect maternal cardiovascular, uterine artery or fetal arterial Doppler parameters.

Administration, Cutaneous↗
PubMed1997

[Abnormal response of growth hormone to oral glucose tolerance test in obesity].

In obesity, it is well known that basal growth hormone (GH) levels can be suppressed and they may show an impaired response to various stimuli like hypoglycemia, stress, and GHRH. However, the inhibitory effect of hyperglycemia on GH in this condition has not been well studied. We analyzed the GH response to an oral glucose tolerance test (OGTT) in 25 unselected patients with morbid obesity who were not diabetic, glucose intolerant or affected by renal or hepatic disease. Ten (40%) of the 25 subjects had an abnormal response of GH to the OGTT, expressed by a lack of suppression of GH levels below 2 micrograms/L within 60 minutes of glucose administration. Three subjects even had a paradoxal increase of GH levels of more than 50% of the basal level. There was no significant difference between these subjects regarding their age, BMI and, serum levels of glucose, insulin, C peptide, or insulin/glucose ratio. After weight loss, three of four patients normalized their GH response. Thus, we conclude that patients with morbid obesity frequently have an abnormal response of GH to OGTT (40% vs 4-8% in normal subjects). This finding must be taken into consideration when interpreting GH levels in these patients. A normalization of this response can be expected after weight loss.

Adult↗
PubMed1996

Peptide-specific T cell clonal expansion in vivo following immunization in the eye, an immune-privileged site.

To visualize the primary antigen-specific T cell response to Ag introduced into the eye, we have used an adoptive transfer system in which a limiting number of OVA peptide (323-339)-specific T cells from a TCR-transgenic mouse were transferred into nonirradiated, syngeneic recipients and then tracked in vivo by staining for FACS analysis or immunohistochemistry with the clonotypic mAb KJ1-26. Following posterior chamber injection of Ag, KJ1-26+ cells accumulated primarily in the draining, submandibular lymph node (LN) within 3 days. Although reduced in number, by day 6 these cells were primarily in the paracortical regions and were able to proliferate and secrete IL-2 in response to Ag stimulation. In contrast, following i.v. injection of Ag, the KJ1-26+ cells accumulated in the paracortical regions of the LN to a comparable degree, but did not proliferate or secrete IL-2. The day 3 accumulation of KJ1-26+ cells in the submandibular LN was inhibited if the eye was removed within 5 h after injection of Ag. In the spleen, foci of KJ1-26+ cells were observed in the periarteriolar lymphoid sheaths at day 3; these were not observed to the same degree following other forms of immunization. These results demonstrate that the submandibular LN is the primary site for early clonal expansion of antigen-specific T cells following intraocular Ag administration and that these cells show changes consistent with immunity rather than tolerance.

Adoptive Transfer↗
PubMed1996

HOOKLESS1, an ethylene response gene, is required for differential cell elongation in the Arabidopsis hypocotyl.

Bending in plant tissues results from differential cell elongation. We have characterized Arabidopsis "hookless" mutants that are defective in differential growth in the hypocotyl. HOOKLESS1 was cloned and its predicted protein shows similarity to a diverse group of N-acetyltransferases. HOOKLESS1 mRNA is increased by treatment with ethylene and decreased in the ethylene-insensitive mutant ein2. High level expression of HOOKLESS1 mRNA results in constitutive hook curvature. The morphology of the hookless hypocotyl is phenocopied by inhibitors of auxin transport or by high levels of endogenous or exogenous auxin. Spatial patterns of expression of two immediate early auxin-responsive genes are altered in hookless1 mutants, suggesting that the ethylene response gene HOOKLESS1 controls differential cell growth by regulating auxin activity.

Alleles↗
PubMed1996

Otolith-semicircular canal interaction during postrotatory nystagmus in humans.

The otolith-semicircular canal interaction during postrotatory nystagmus was studied in ten normal human subjects by applying fast, short-lasting, passive head and body tilts (15, 30, 45, or 90 degrees in the roll or pitch plane) 2 s after sudden stop from a constant-velocity rotation (100 degrees/s) about the earth-vertical axis in yaw. Eye movements were measured with three-dimensional magnetic search coils. Following the head tilt, activity in the semicircular canal primary afferents continues to reflect the postrotatory angular velocity vector in head-centered coordinates, whereas otolith primary afferents signal a different orientation of the head relative to gravity. Despite the change in head orientation relative to gravity, postrotatory eye velocity decayed closely along the axis of semicircular canal stimulation (horizontal in head coordinates) for large head tilts (90 degrees) and also for small head tilts (15-45 degrees) for reorientations in the pitch plane. Only for small head tilts (15-45 degrees) in the roll plane was there a reorientation of the eye rotation axis toward the gravitational vector. This reorientation was approximately compensatory for 15 degrees head tilts. For 30 degrees and 45 degrees head tilts the eye rotation axis tilted toward the gravitational vector by about the same amount as for 15 degrees head tilts. These results suggest that, with the exception of small head tilts in the roll plane, there was no compelling data showing a relationship between the eye rotation axis and head tilt and that postrotatory nystagmus is largely organized in head-centered rather than gravity-centered coordinates in humans. This indicates a rudimentary, nonlinear, and direction-specific interaction of semicircular canal and otolith signals in the central vestibular system in humans.

Adult↗
PubMed1996

The role of plant clinics in plant disease diagnosis and education in developing countries.

The scarcity of literature in the realm of plant clinics operating in the developing world brought us to the decision to perform a survey in non-OECD countries in Africa, Asia and Oceania, Latin America and the Caribbean, and in central and southern Europe. Forty-one completed questionnaires that refer to 79 plant clinics were returned. The best-equipped clinics are operated by the international research bodies. By and large, this review shows that considerable progress has been achieved in the physical development of plant clinics in developing countries and in staffing them with well-trained personnel. Not surprisingly, however, many inadequacies and inconsistencies still need to be addressed before clinics can fully play their part in providing plant protection services to their clients. Success and constraining indicators in the diagnostic performance of the clinics are identified. A model of the'ideal plant clinic' is suggested.

Journal Article↗
PubMed1996

Immigration and social justice: towards a progressive European immigration policy?

"Stepping back from current debates over immigration in the new 'Fortress Europe', this paper examines moral and philosophical arguments for an alternative and more 'progressive' immigration policy. Despite recent interest within geography in principles of social justice, the extent to which such principles reach beyond particular societies or nations has rarely been considered explicitly. The notion of social justice may be extended to the question of immigration, without taking the position that migration should itself be seen as a 'human right'. Even within relatively conservative contractarian and communitarian conceptions of social justice, a number of suggestions can be made for 'progressive' policy options, in particular by focusing on the communal rights and duties of societies rather than the human rights of individual migrants."

Developed Countries↗
PubMed1996

Estimating the completeness of under-5 death registration in Egypt.

To evaluate the completeness of registration of infant and child deaths in Egypt, reinterviews were conducted with families who had reported a death of a child under age 5 in the five years before the survey for two national surveys recently conducted in Egypt: the United Nations PAPCHILD survey of 1990-1991 and the Egyptian Demographic and Health Survey (EDHS) of 1992. The survey instrument included questions regarding notification of the death at the local health bureau. If the family said the death had been notified, separate employees searched the health bureau records for the registration. Overall 57% of infant deaths were reported as notified and 68% of those death reports were found; the corresponding figures for child death were 89% and 74%. Using the percentage reported as notified as an estimate for completeness of registration, we adjusted upward the national infant and child mortality rates from registration data, giving values of 73 per 1,000 for infant mortality and 99 for 5qo for the period 1987-1990. These values are approximately 20% above the corresponding direct estimates from the PAPCHILD and EDHS surveys.

Adult↗
PubMed1995

Prevention of SIV infection in macaques by (R)-9-(2-phosphonylmethoxypropyl)adenine.

The efficacy of pre- and postexposure treatment with the antiviral compound (R)-9-(2-phosphonylmethoxypropyl)adenine (PMPA) was tested against simian immunodeficiency virus (SIV) in macaques as a model for human immunodeficiency virus (HIV). PMPA was administered subcutaneously once daily beginning either 48 hours before, 4 hours after, or 24 hours after virus inoculation. Treatment continued for 4 weeks and the virologic, immunologic, and clinical status of the macaques was monitored for up to 56 weeks. PMPA prevented SIV infection in all macaques without toxicity, whereas all control macaques became infected. These results suggest a potential role for PMPA prophylaxis against early HIV infection in cases of known exposure.

Adenine↗
PubMed1995

Community infection ratio as an indicator for tuberculosis control.

The epidemiology of tuberculosis remains poorly understood. We investigated the relative importance of within-household and community transmission of infection among children aged 6 months to 14 years living in a Peruvian shanty-town. The prevalence of Mycobacterium tuberculosis exposure among 175 contact children (sharing a household with a person who had confirmed pulmonary tuberculosis) and 382 control children (living in nearby households free of active tuberculosis) was defined as the proportion of children with a positive purified protein derivative (PPD) skin-test. 97 (55%) contact children and 129 (34%) controls were PPD positive. Living in a contact household (odds ratio 1.74, 95% CI 1.11-2.73) and age (1.11, 1.06-1.18) were significant risk factors for PPD positivity. We calculated the community infection ratio (CIR) as the odds ratio of PPD-positive controls to PPD-positive contacts: CIR = [formula: see text] A low CIR therefore suggests mainly household spread of infection, whereas a high value suggests frequent transmission outside the household. The adjusted odds ratio (for age, sex, within-household correlation, and household size) was 0.40 (95% CI 0.26-0.64), compared with values of 0.18-0.37 in studies elsewhere. Currently recommended tuberculosis control strategies are suitable for areas with low CIRs. Different strategies may be needed for areas, such as that we studied, with high values.

Adolescent↗
PubMed1995

Prevalence of sexual abuse among patients with functional disorders of the lower gastrointestinal tract.

To evaluate the links between gastrointestinal disorders and sexual abuse, we asked 344 patients consulting in a specialized tertiary care university hospital or a gastroenterologist in private practice, if they had been sexually abused. Forty per cent of patients suffering from lower functional digestive disorder gave a history of having been victims of sexual abuse in contrast to only 10% of patients with organic diseases (P < 0.0003). The prevalence was similar in private practice and in the university hospital. Abused patients were more likely to complain of constipation (P < 0.03) and diarrhoea (P < 0.04). Anismus was more frequent in patients who had been sexually abused (P < 0.02). The prevalence of abuse was four times greater in patients with lower than with upper functional motor disorders of the gastrointestinal tract (P < 0.002). This study confirms the large prevalence of a past history of sexual abuse among patients consulting for gastrointestinal tract functional disorder, and this whatever the kind of recruitment may be. It shows the association to be much stronger in patients who have a lower rather than an upper gastrointestinal dysfunction, the major complaint of abused patients being constipation and diarrhoea.

Adolescent↗
PubMed1995

Caretaker compliance with different antibiotic formulations for treatment of childhood pneumonia.

To determine the effect of antibiotic formulations on compliance, 400 children, aged 2 months to 5 years, with a presumptive diagnosis of pneumonia, were randomly assigned to receive one of the following formulations of cotrimoxazole: 1. syrup accompanied by a 10-ml measuring cup; 2. syrup accompanied by a 5-ml measuring spoon; 3. tablets; 4. single-dose sachets of antibiotic powder. A research assistant visited the childs' home on the fourth day of therapy, asked the care-giver about compliance, and observed the care-giver prepare a dose of the medication. The remaining amount of medicine was measured, and when possible (n = 151), a urine specimen was tested for the presence of sulphamethoxazole. All of the care-givers reported giving at least one dose on the first day of therapy. By the fourth day, 82 per cent of those receiving syrup were still taking their medication compared to 71 and 55 per cent of those receiving sachets or tablets, respectively (P < 0.01). Of those who received syrup accompanied by a spoon, 38 per cent under-dosed the medicine by at least 30 per cent. Overall, compliance was highly correlated with the care-giver's report of difficulty in administering the medication. Additional research is needed to understand the obstacles encountered by care-givers in administering sachets and tablets. Meanwhile, the use of antibiotic syrup, accompanied by an appropriately sized measuring cup, appears to offer the greatest probability of medication compliance in the treatment of Egyptian children with pneumonia.

Analysis of Variance↗
PubMed1995

Epidemiology of presenile Alzheimer's disease in Scotland (1974-88) I. non-random geographical variation.

BACKGROUND: Factors that determine geographical differences in incidence rates of 'probable' presenile Alzheimer's disease (AD PSD) may help to clarify the possible role of the environment in its aetiology. METHOD: We have ascertained the treated incidence of AD PSD in Scotland by scrutiny of hospital cassenotes and searched for cases outside hospital settings. Small area geographical analysis compared the observed distribution of cases (each allocated to one of Scotland's 898 postcode sectors) with the estimated random distribution of cases. RESULTS: There was non-random geographical distribution of AD PSD but not of the comparison conditions (vascular dementia (VaD), motor neurone disease, prostatic or ovarian cancers). Substantial differences between Scottish regions were probably not attributable to methodological artefact, as other techniques of case finding showed the same regional differences. CONCLUSIONS: The observed differences in incidence of AD PSD between Scotland's regions are real and some localities have a higher incidence, mostly in central Scotland.

Adult↗
PubMed1995

Diarrhoeal diseases in the White Mountain Apaches: clinical studies.

Acute diarrhoeal diseases continue to be a major health problem in certain underprivileged populations in the United States, including native Americans living in reservations. To describe the features of patients with diarrhoeal diseases requiring medical care, those attending the medical facilities of the Fort Apache Indian Reservation, Whiteriver, Arizona, were studied during 1981-1985. Clinical and aetiological information was obtained on 535 patients which constitute a 20% sample of those attending the outpatient clinic and all 386 patients who required 550 hospitalizations. Rotavirus, enterotoxigenic Escherichia coli, and Shigella were the most common aetiologic agents, a pattern similar to that seen in the developing countries. The clinical features of diarrhoeal illness and the frequent associated occurrence of acute respiratory symptoms, however, were remarkably similar, regardless of aetiology.

Acute Disease↗
PubMed1995

Diarrhoeal diseases in the White Mountain Apaches: epidemiologic studies.

Acute diarrhoeal disease in children is known to be a major public health problem among native Americans living in reservations in the southwestern part of the United States. This study was undertaken to describe the epidemiology and causative agents of diarrhoea more completely, with the expectation that this information may help in the ultimate control of the disease in this population. Three interrelated epidemiologic studies were carried out in the White Mountain Apache Tribe, Whiteriver, Arizona, during 1981-1985: a three-year longitudinal study on a cohort of 112 newborns, a longitudinal two-year study in a cohort of 200 families, and a case-control study on 1,072 children with diarrhoea attending a medical facility. Both epidemiologic and microbiological patterns of diarrhoeal disease were found to be very similar to those seen in developing countries, indicating the need for basic improvements in sanitation and hygiene in this population.

Acute Disease↗