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Biomedical subjects

G M Raab

Publications and source records attributed to G M Raab.

At least 37 records · Page 2Linked to original sources
PubMed1995

HIV infection in women: immunological markers and the influence of pregnancy.

OBJECTIVE: To describe the influence of pregnancy on immunological marker paths and progression of HIV-infected women. DESIGN: Analysis of prospectively collected immunological and clinical data collected on 145 women reviewed at the City Hospital, Edinburgh, between 1985 and 1992 using a two-level random-effects model that allows for within- and between-patient variance. RESULTS: There were differences between the marker paths of women according to risk activity; women who had acquired HIV via injecting drug use (in addition to heterosexual intercourse) had a higher level of absolute CD4 cells, CD4% and total lymphocytes at seroconversion than those who had acquired HIV via heterosexual intercourse alone; however, immunological markers declined more steeply after seroconversion. There was no evidence that pregnancy, either before or after HIV seroconversion had an adverse effect on marker paths of HIV disease. There was a significant association between pregnancy after HIV seroconversion and post-pregnancy changes in immunological markers: an increase in the CD4% and a decrease in CD8%. However, causality cannot be implied as pregnancy itself may be associated with considerable lifestyle changes. During pregnancy the total white blood count rose due to an increase in the number of granulocytes, whereas the total lymphocyte numbers fell. The absolute CD4 lymphocyte subset counts fell progressively but the effect was due to the fall in the total lymphocyte counts, there being no influence of pregnancy on either CD4% or CD8%. CONCLUSIONS: In asymptomatic HIV infection, changes in the absolute levels of CD4 and CD8 lymphocyte counts are primarily related to changes in the other components of the white cell count because there were no changes in CD4% and CD8%. Pregnancy itself has no adverse effect on immunological markers of HIV.

Adult↗
PubMed1994

Deaths, HIV infection, abstinence, and other outcomes in a cohort of injecting drug users followed up for 10 years.

OBJECTIVE: To trace, follow up, and interview a group of patients known to be injecting drug users in order to establish current drug taking and other features related to drug use over 10 years. DESIGN: Descriptive follow up study of a cohort of injecting drug users established between 1982 and 1985. SETTING: General practice based patient population study initially, with later tracing of subjects throughout the United Kingdom through NHS Central Registries and current general practitioners. SUBJECTS: 203 injecting drug users recruited up to December 1985. MAIN OUTCOME MEASURES: Survival, cause of death, abstinence, or continued drug use; HIV status; and demographic variables. RESULTS: Of the 203 injecting drug users recruited into the study, over half were known to be HIV positive and 42 died of various causes (increasingly AIDS). From the start of follow up in 1990, 163 (91%) of the 180 survivors were traced, of whom 116 (71%) were interviewed. Dramatic changes had occurred in drug taking, with a move away from injecting towards oral drug use. A few patients, however, continued to inject. 90 (78%) of those interviewed had been in prison, of whom 37 (41%) had injected drugs while in prison. CONCLUSIONS: The pattern of deaths had changed from being largely due to overdose in the early 1980s to predominantly AIDS related in later years. The reduction in deaths due to overdose may have been connected with but was not always causally related to a new approach by legal, social, and medical services. Drug use continues in a modified form in a large proportion of patients followed up. As a group, drug users require long term support for a multiplicity of problems.

Adult↗
PubMed1994

Age-related ranges of memory, activation, and cytotoxic markers on CD4 and CD8 cells in children.

The expression of markers defining functional subpopulations on the surface of CD4 and CD8 cells changes with disease. To monitor these changes in children, it is important to establish the age-related normal changes in marker expression due to maturation of the immune system. We have studied the expression of several functionally important molecules on both CD4 and CD8 cells in 168 children (aged 0-122 months) using monoclonal antibodies and flow cytometry. Our results show that the percentage of CD4 cells decreases with age, while the CD8 percentage increases, resulting in a decrease in the CD4/CD8 ratio. The expression of CD45RO and CD29 increases with age, while CD45RA expression decreases, both on CD4 and CD8 cells. The expression of HLA-DR on both CD4 and CD8 cells, and of CD11a and CD57 on CD8 cells, is less clearly age dependent. The relationships between the marker percentages and age were not straightforward; the standard deviations and the skewness, as well as their mean values, varied as a function of age. The changes were modeled for each marker and age-specific centiles are presented.

Aging↗
PubMed1993

Bayesian analysis of binary data from an audit of cervical smears.

A large data set of unsatisfactory smear rates from 629 different cervical smear takers is used to illustrate a Bayesian approach to the analysis of medical audit data with a binary outcome. It is shown that this gives more relevant results in terms of characterizing individual smear takers than frequentist methods, and that the full Bayesian analysis is preferable to an empirical Bayes approximation when the number of different smear takers is small and at least one individual smear taker has contributed only a few smears. Plots of Bayesian posterior distributions with 95 per cent confidence sets are suggested as a useful way of feeding back the results to individual clinicians.

Adult↗
PubMed1993

Macrophage prostaglandin E2 and oxidative responses to endotoxin during immunosuppression associated with anaesthesia and transfusion.

The widespread use of blood transfusion in major surgical procedures has led to concern about the immunosuppressive effect of transfusion on patients with underlying malignancy. Transfusion may also suppress the host response to infection. The cellular mechanisms of transfusion-associated immunosuppression may involve macrophage prostaglandin E2 (PGE2) in modulating the host response to cancer and infection. We previously observed that the transfusion of blood increased PGE2 production by unstimulated macrophages. To investigate this PGE2 associated immunosuppression, we studied the effect of transfusion of rats using a physiological stimulus of macrophage PGE2 production, bacterial endotoxin. In the same macrophages, we analysed intracellular oxidative activity. Both allogeneic and syngeneic blood transfusion were associated with increased PGE2 release by macrophages. This stimulation of PGE2 increased with duration of storage of blood. A similar effect of serum indicated that a humoral factor was involved. Endotoxin (50 ng/ml-500 micrograms/ml) stimulated PGE2 production in all transfused subjects. The lowest endotoxin concentration gave proportionately the greatest stimulation. Oxidative activity was down-regulated in macrophages of transfused rats, supporting an immunosuppressive role of PGE2 within the macrophage. An effect of surgery on the oxidative response was also detected.

Anesthesia↗
PubMed1993

Ultrasonically determined patterns of enlargement in benign prostatic hyperplasia.

A series of 430 men aged 40 to 79 years underwent transrectal ultrasonography (TRUS) as part of a community survey of benign prostatic hyperplasia (BPH). We describe a reproducible method of prostate volume estimation and discuss the implications of prostate dimension changes in BPH. The mean prostate and adenoma volumes for the group were 32 ml (SD 14) and 15 ml (SD 11) respectively. The antero-posterior dimension of the prostate (APD) had the strongest correlation with gland volume compared with the transverse dimension (TD) and length (L). The mean ratio of adenoma volume to prostate volume was 0.45 (SD 0.13) and this increased with increasing gland volume. There was a modest correlation between the ratio and prostate volume. BPH is characterised by a proportionally greater increase in the APD compared with L and TD and by an increasing adenoma/prostate ratio. TRUS is useful in assessing the type and extent of adenoma and prostate enlargement in BPH.

Adult↗
PubMed1990

The accuracy of simple ordinal scoring of tooth attrition in age assessment.

Tooth wear is frequently used as a method of ageing skeletal remains. Fundamental to this method is the ability to measure the amount of tooth wear. The Brothwell chart based on the Miles method of ageing, uses simple ordinal scoring and is frequently used by archeologists. The purpose of the present investigation was to evaluate the accuracy of simple ordinal scoring in recording tooth wear and ageing skulls. A group of Chinese skulls of known age at death was used. The age range was from 16 to 60 years. A single score per molar tooth was used to record occlusal wear. The data were analysed by regression methods using BMDP statistical software. The results showed that molar tooth wear continues throughout the life of the individual. The first molar teeth wear significantly more quickly than do second molar teeth. Use of a simple ordinal score method for recording wear gives an inaccurate estimate of an individual skull's age at death with a very wide 95% confidence interval.

Adolescent↗
PubMed1990

Prostaglandin E2 production by rat peritoneal macrophages: role of cellular and humoral factors in vivo in transfusion-associated immunosuppression.

The transfusion of blood is associated with long-term immunosuppression, which has been postulated to influence immunosurveillance and cancer cell killing. The mononuclear phagocyte synthesises large quantities of PGE2, and PGE2 has been shown to inhibit the activity of a range of immunocompetent cell types. The role of mononuclear phagocyte PGE2 synthesis in transfusion-associated immunosuppression, and the elements of transfused blood which control this immunosuppression, were investigated using a transfused rat model. A significant increase in macrophage PGE2 synthesis was detected 7 days after transfusion with blood and serum. The storage of blood for 24 h increased the stimulatory activity of transfused blood. The effects of storage and serum on macrophage PGE2 synthesis were greater than effects due to genetic differences between blood donor and recipient, and the serum effects indicated that a major factor activating PGE2-mediated immunosuppression in transfused subjects may be humoral in nature.

Animals↗
PubMed1989

Blood-lead levels and children's behaviour--results from the Edinburgh Lead Study.

The effect of blood-lead on children's behaviour was investigated in a sub-sample of 501 boys and girls aged 6-9 years from 18 primary schools within a defined area of central Edinburgh. Behaviour ratings of the children were made by teachers and parents using the Rutter behaviour scales. An extensive home interview with a parent was also carried out. Multiple regression analyses showed a significant relationship between log blood-lead and teachers' ratings on the total Rutter score and the aggressive/anti-social and hyperactive sub-scores, but not the neurotic sub-score when 30 possible confounding variables were taken into account. There was a dose-response relationship between blood-lead and behaviour ratings, with no evidence of a threshold.

Aggression↗
PubMed1989

Ventilatory and arousal responses to added inspiratory resistance during sleep.

Airway resistance increases during sleep. We have determined the ventilatory and arousal responses to the addition of inspiratory resistance of 4, 7, or 10 cmH2O/L/s during sleep in 10 normal men who slept wearing valved face masks. Insufficient ventilatory response data were obtained during rapid eye movement (REM) sleep to allow adequate analysis. The immediate responses to loading were decreases in tidal volume (VT), breathing frequency (f), and minute ventilation (VE), with no difference between wakefulness and Stage 2 and Stage 3/4 sleep in the effects of loading on VT and VE, but f fell more during wakefulness than during sleep (p less than 0.05) because of a greater lengthening of inspired time (TI) (p less than 0.05). During the first 10 breaths, occlusion pressure (P0.1) increased similarly in all EEG stages. Averaging responses during the 2-min periods when resistances were applied, the only variable to differ between EEG stages was TI, which increased more in wakefulness than in Stage 2 or Stage 3/4 sleep (p less than 0.01). Arousal within 2 min of application of resistance occurred less frequently from Stage 3/4 sleep than from Stage 2 or REM sleep (p less than 0.02). The study demonstrates that sleep modifies the changes in respiratory timing produced by resistive loading without having a major effect on ventilation or P0.1 responses. The low frequency of arousal from Stage 3/4 sleep with loading may explain why asthmatics rarely awaken from this stage with wheeze.

Adult↗
PubMed1988

Factors influencing lead concentrations in shed deciduous teeth.

Data collected for the Edinburgh Lead Study have been used to investigate lead concentrations in children's naturally shed deciduous teeth. A within-child multiple-regression analysis has shown that the upper jaw has a higher concentration of lead than the lower, and that there is a gradient of decreasing concentration from the front to the back of the mouth. Even after the effects of jaw and tooth type have been allowed for, the concentration is still found to be negatively correlated with the weight of the tooth and with the age at which the tooth was shed. No statistically significant effects could be attributed to caries, fillings, or the incomplete resorption of roots. A single-valued index of tooth lead has been derived for each child, taking into account the fact that children gave different types of teeth.

Age Factors↗
PubMed1987

Children's blood lead and exposure to lead in household dust and water--a basis for an environmental standard for lead in dust.

Good quantitative evidence on the role of lead in household dust as a source of exposure to children has been lacking. A study of 495 children in Edinburgh, Scotland shows a significant relationship between lead in dust vacuumed from the floors of the children's homes and their blood lead levels. A multiple regression analysis incorporating drinking water and household dust estimates that a 1,000 micrograms g-1 increase in dust lead concentration would increase blood lead by 1.9 micrograms dl-1, for a child with the median population blood lead of 10.1 micrograms dl-1. Dust lead concentration is a more useful predictor of blood lead than lead loading. The sanding or blow-lamp stripping of old paint is found to be an important source of the higher household dust lead concentrations. Finally, the dust lead-blood lead relationship is used to derive a standard for lead in house dust, as no such standard exists for this exposure route.

Child↗
PubMed1986

Guidelines for selective radiological assessment of inversion ankle injuries.

A prospective study was performed to establish definitive guidelines for selective use of radiography in the assessment of inversion ankle injuries. Five hundred patients were included, representing 3.2% of the workload of the department during the study period. There were 379 soft tissue injuries, 56 malleolar fractures, 40 avulsion fractures, 21 fractures at the base of the fifth metatarsal, and four calcaneal fractures. Multiple logistic regression identified distal fibular tenderness, age, and ability to bear weight as the most important clinical variables in predicting important fractures (p less than 0.001). A policy of requesting x ray examination of only those patients with distal fibular tenderness or inability to bear weight or aged over 60, with a further proviso that no foot radiographs should be obtained, would produce a 60% reduction in ankle radiography in this centre without detriment to patient care.

Adolescent↗
PubMed1986

Do asthmatics suffer bronchoconstriction during rapid eye movement sleep?

Many patients with asthma are troubled by nocturnal wheeze. The cause of this symptom is unknown, but sleep is an important factor. A study was carried out to determine whether nocturnal bronchoconstriction is related to any specific stage of sleep. Eight asthmatics with nocturnal wheeze and eight control subjects performed forced expiratory manoeuvres immediately after being woken from rapid eye movement (REM) or non-REM sleep, wakings being timed to differentiate temporal effects from those related to the stage of sleep. The control subjects showed no significant temporal bronchoconstriction or bronchoconstriction related to the stage of sleep. All patients showed bronchoconstriction overnight, the mean peak expiratory flow rate falling from 410 (SEM 50) 1/min before sleep to 186 (49)1/min after sleep. After the patients had been woken from REM sleep the forced expiratory volume in one second was on average 300 ml lower (p less than 0.02) and peak expiratory flow rate 45 1/min lower (p less than 0.03) than after they had been woken from non-REM sleep. As wakenings from REM sleep were 21(8) minutes later in the night than those from non-REM sleep multivariate analysis was performed to differentiate temporal effects from those related to the stage of sleep. This showed that the overnight decreases in forced expiratory volume in one second and peak expiratory flow rate were significantly related both to time and to REM sleep. This study suggests that asthmatics may suffer bronchoconstriction during REM sleep.

Adolescent↗
PubMed1985

Guidelines for immunoassay data processing.

These guidelines outline the minimum requirements for a data-processing package to be used in the immunoassay laboratory. They include recommendations on hardware, software, and program design. We outline the statistical analyses that should be performed to obtain the analyte concentrations of unknown specimens and to ensure adequate monitoring of within- and between-assay errors of measurement.

Computers↗
PubMed1983

Comparison of a logistic and a mass-action curve for radioimmunoassay data.

This paper compares a logistic curve and a mass-action curve in their ability to represent radioimmunoassay standard curves. A data base from 10 different assays is used in this comparison. Six of the 10 assays could be modeled equally well by either the logistic or the mass-action curve. In one case the mass-action curve gave a slightly better fit, though the practical distinction was negligible. In the remaining three assays the mass-action curve performed very much worse than the logistic curve. It is shown that the mass-action curve can assume only a very limited range of shapes, which explains its difficulty with these three assays. In particular, the mass-action curve cannot represent assays where the standard curve slope is less than a specified value. The paper also discusses the extension of each of these curves to more complicated equations, and their application to immunoassay data.

Computers↗
PubMed1982

Cell turnover in the "resting" human breast: influence of parity, contraceptive pill, age and laterality.

Morphological identification of cell multiplication (mitosis) and cell deletion (apoptosis) within the lobules of the "resting" human breast is used to assess the response of the breast parenchyma to the menstrual cycle. The responses are shown to have a biorhythm in phase with the menstrual cycle, with a 3-day separation of the mitotic and apoptotic peaks. The study fails to demonstrate significant differences in the responses between groups defined according to parity, contraceptive-pill use or presence of fibroadenoma. However, significant differences are found in the apoptotic response according to age and laterality. The results highlight the complexity of modulating influences on breast parenchymal turnover in the "resting" state, and prompt the investigation of other factors as well as steroid hormones and prolactin in the promotion of mitosis. The factors promoting apoptosis in the breast are still not clear.

Adenofibroma↗