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Biomedical subjects

S F Ho

Publications and source records attributed to S F Ho.

At least 19 recordsLinked to original sources

The management of primary rhegmatogenous retinal detachment not involving the fovea.

AIM: To establish the likelihood of, and risk factors associated with, progression of 'macula-on' retinal detachment. METHODS: A multi-centre prospective observational study of patients with acute retinal detachment, not involving the fovea, was conducted over a 6-month period. Data collected included duration of symptoms, visual acuity, presence of posterior vitreous detachment, retinal drawings and subretinal fluid (SRF) distance from the fovea at a minimum of two time points. RESULTS: A total of 82 data sets from 15 institutions were analysed. Of 82 cases 11 (13%) demonstrated progression of fluid. Mean progression in those cases which progressed was 2.3 disc diameters (dd) and the average rate of progression was 1.80 dd/day. Binary regression analysis failed to reveal any statistically significant risk factors for progression. Multiple regression analyses were made to identify risk factors. With distance of SRF from fovea at operation as a function, distance of SRF at presentation was the only statistically significant risk factor. In all, 26% of patients underwent surgery out-of-hours. A total of 83% patients achieved a 6-week best-corrected vision of 6/9 or better. CONCLUSION: Most retinal detachments in this study did not progress within the first few days. The distance of SRF from the fovea at presentation was the only statistically significant risk factor for progression to foveal detachment.

Acute Disease↗

Dyspnoea and quality of life in older people at home.

OBJECTIVES: To determine the prevalence of dyspnoea in older people at home, measure its impact on function and quality of life, and identify associated cardio-respiratory diseases. DESIGN: Cross-sectional population-based study. METHODS: We sent a modified Medical Research Council (MRC) dyspnoea questionnaire to identify breathlessness in 1404 randomly selected subjects from general practitioner lists of 5002 subjects aged 70 years and over living at home. We visited a further random sample of 500 of these subjects at home and at a study centre. SETTING: Community-based study in South Wales. MAIN OUTCOME MEASURES: Prevalence of dyspnoea (MRC grades 3-5) and its effect on psychological and functional status, and quality of life as measured by Hospital Anxiety and Depression, Nottingham Extended Activities of Daily Living and SF-36 questionnaires. RESULTS: The prevalence of dyspnoea as defined was 32.3% (95% confidence intervals: 30.3, 34.3). Breathless subjects had poorer functional status than non-breathless subjects. They also had poorer physical and mental health and were more likely to be anxious and depressed. The prevalence of left ventricular systolic dysfunction, reversible airways disease and obesity were all higher in those with dyspnoea. CONCLUSIONS: Dyspnoea is common in older people. Given its profound adverse effect on people's lives, dyspnoea is an important public health issue.

Aged↗

Morbidity in older people with self-reported asthma.

OBJECTIVE: To investigate the differences in physical and psychological morbidity in older people with and without self-reported asthma and whether these are associated with use of more medication and hospital services. DESIGN: Cross-sectional study of changes in health services for older people. SETTING: South Wales in 1990 and 1992. SUBJECTS: A population-based random sample of 2818 people aged 65 years and over. MAIN OUTCOME MEASURES: Prevalence of self-reported asthma; assessment of disability, anxiety, depression and memory using standardized measures; mobility; use of prescribed medication and hospital services. RESULTS: 231 subjects with self-reported asthma were identified. The prevalence of asthma was 8%, which was not significantly different between the sexes (P = 0.88), age groups (P = 0.06) or social classes (P = 0.108). There was a significant relationship between asthma and functional and physical disability (severe disability 29% vs 16%, P < 0.0001), mobility (housebound 7% vs 4%, P < 0.05), anxiety (37% vs 20%, P < 0.0001), depression (19% vs 10%, P < 0.001), poor perceived health status (23% vs 9%, P < 0.0001), number of different medications (seven or more, 13% vs 4%, P < 0.0001) and inpatient (P < 0.0001) and outpatient (P < 0.05) use of hospital services. CONCLUSIONS: There is excess psychological and physical morbidity and poorer perceived health status in older people with self-reported asthma.

Aged↗

Lead exposure in the lead-acid storage battery manufacturing and PVC compounding industries.

This study was conducted as part of the Human Exposure Assessment Location (HEAL) Project which comes under the United Nations Environment Programme/World Health Organisation (UNEP/WHO) Global environmental Monitoring System (GEMS). The objective of the study was to evaluate workers' exposure to lead in industries with the highest exposure. All subjects were interviewed about their occupational and smoking histories, the use of personal protective equipment and personal hygiene. The contribution of a dietary source of lead intake from specified foods known to contain lead locally and personal air sampling for lead were assessed. A total of 61 workers from two PVC compounding and 50 workers from two lead acid battery manufacturing plants were studied together with 111 matched controls. In the PVC compounding plants the mean lead-in-air level was 0.0357 mg/m3, with the highest levels occurring during the pouring and mixing operations. This was lower than the mean lead-in-air level of 0.0886 mg/m3 in the lead battery manufacturing plants where the highest exposure was in the loading of lead ingots into milling machines. Workers in lead battery manufacturing had significantly higher mean blood lead than the PVC workers (means, 32.51 and 23.91 mcg/100 ml respectively), but there was poor correlation with lead-in-air levels. Among the lead workers, the Malays had significantly higher blood lead levels than the Chinese (mean blood levels were 33.03 and 25.35 mcg/100 ml respectively) although there was no significant difference between the two ethnic groups in the control group. There were no significant differences between the exposed and control group in terms of dietary intake of specified local foods known to contain lead. However, Malays consumed significantly more fish than the Chinese did. There were no ethnic differences in the hours of overtime work, number of years of exposure, usage of gloves and respirators and smoking habits. Among the Malays, 94.3% eat with their hands compared with 9.2% of the Chinese. Workers who ate with bare hands at least once a week had higher blood lead levels after adjusting for lead-in-air levels (mean blood lead was 30.2 and 26.4 mcg/100 ml respectively). The study indicated that the higher blood lead levels observed in the Malay workers might have been due to their higher exposure and eating with bare hands.

Adult↗

Study on musculoskeletal complaints involving the back, neck and upper limbs.

OBJECTIVE & METHODS: A mail questionnaire survey was conducted among designated factory doctors (DFDs) to determine the nature and extent of musculoskeletal aches/pains in patients attending their clinics over one working week. Information was recorded for all patients aged 15 years and above presenting with aches or pains in the back, neck or upper limbs, as the main complaint or as one of the presenting symptoms. RESULTS: For the 155 doctors participating in the survey, the total attendance of patients aged 15 years and above during the study period was 35,010. Of these, 3.9% presented with the symptoms studied and 1.8% had work-related complaints. The commonest site affected was the back (55.7%), followed by the neck (21.4%) and shoulders (19.2%). A higher proportion of males than females had back complaints with the reverse for complaints involving hands/wrists and arms/forearms. 82.3% of the affected were employed, 60.3% being production workers, compared to 33.3% professional/office workers and 6.4% service workers. Of the patients who were working, 51.3% had work-related symptoms and 54.4% were given medical leave. Production workers had the highest proportion with work-related symptoms while service workers had the highest proportion given medical leave. The "medical certificate rate" was highest for back symptoms -57.6%, while work-related symptoms was highest for complaints involving hands/wrists. CONCLUSION: The study findings are consistent with those of a 1993 morbidity survey of outpatients in Singapore and indicate that the prevalence of work-related musculoskeletal aches/pains is not high.

Adolescent↗

The significance of aches/pains among workers in an electronics factory.

Three hundred and fifteen female workers with at least three months' employment history in a factory manufacturing disk drives were studied. Each worker completed a self-administered questionnaire on their personal particulars, hours of work, opinion on the work and the workplace and the presence and severity of aches/pains experienced over the past one month. One hundred and forty one (44.8%) of the workers had complaints of aches/pains. Of these, 81 (57.5%) reported an improvement in their symptoms during their off-days. 59 (41.8%) had symptoms affecting two or more sites. The most commonly affected sites were the hands and shoulders, followed by the head and back. There was no significant difference in the prevalence of symptoms between workers from the different work stations. Ninety four (66.7%) of these workers reported that the pains that were severe enough to affect their activities. 76 (53.9%) had to seek some form of medical treatment while 33 (23.4%) had to be on medical leave. However, the physical examinations of this group of workers were normal. The symptoms appeared to be influenced by their attitude towards work. A significantly higher number of workers with symptoms expressed dissatisfaction with work and had complaints of a noisy and cold environment. The study showed that workers' morale and the quality of the work environment may play an important role in improving their general well-being.

Female↗

Environmental and biological monitoring of occupational exposure to 1,1,1-trichloroethane.

Fifty workers involved in various degreasing and cleaning processes using 1,1,1-trichloroethane (1,1,1-TCE) were studied with respect to personal and static exposures. In addition, end-of-shift expired air and venous blood samples were taken for analysis of the parent compound. Urinary samples were also obtained at the same time for analysis of its metabolites-trichloroethanol (TCOH) and trichloracetic acid (TCA). The results show that open/manual degreasing processes generate the highest environmental solvent levels (mean = 819.9 mg/m3; SD = 781.9 mg/m3) followed by jet-spray cleaning (mean = 460.5 mg/m3; SD = 292.4 mg/m3), vapour degreasing (mean = 365.3 mg/m3; SD = 279.9 mg/m3) and ultrasonic degreasing (mean = 134.7 mg/m3; SD = 121.0 mg/m3). Personal exposure levels were well correlated with concentrations of 1,1,1-TCE in end-of-shift expired air (r = 0.81) and venous blood samples (r = 0.88) but only moderately correlated with concentrations of its metabolites in urine (r = 0.49 for TCOH; r = 0.58 for TCA). Static (area) samples were poorly correlated with the biological exposure indices studied.

Air↗

An investigation into complaints of wrist pain and swelling among workers at a factory manufacturing motors for refrigerators.

In 1987, a group of workers complained through their union that some of them developed wrist pain and swelling from the manual handling of heavy stators. The complaints were from the morning shift of a particular assembly line in a factory making motors for refrigerators. The precipitating factor appeared to be the change in the weight of the model assembled. The new stator weighing 5.8 kg was about twice as heavy as the previous model. Each worker on the line handled 300 to 1,000 stators per shift. The work involved including lifting the stators onto and off the conveyor belts and pushing and pulling them along horizontal planes. To evaluate the problem, workers from both shifts of the affected assembly line were interviewed and examined. A total of 79 workers (all females) was involved. The presence and severity of work-related aches, pains, numbness, swelling, etc over the last 4 weeks were enquired. The nature of the work done in the line was observed. Sixty-three out of 79 workers had some symptoms giving an overall prevalence rate of 79.8%. The two most common complains were pain (90.5%) and numbness (28.6%). The most commonly affected sites were the hands and wrist followed by the neck and shoulder. There was no significant difference in the prevalence of symptoms among workers in the 2 shifts. The symptoms were subjective and associated with job dissatisfaction and there was no difference in the average number of stators handled between those with symptoms and those without.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Contact dermatitis from dielectric fluids in electrodischarge machining.

We report an outbreak of irritant contact dermatitis in the aerospace industry from electrodischarge machining (EDM). 20 workers doing EDM developed irritant contact dermatitis from the dielectric fluid used in EDM, a form of precision metal machining that is widely used in mould making and precision engineering. Dielectric fluid contains hydrocarbons that are aromatic, paraffinic or naphthenic and are skin irritants. Irritant contact dermatitis from dielectric fluid has not been reported previously. EDM will become more widespread and occupational dermatitis from dielectric fluid is likely to become more prevalent in the future. Our experience was that irritant contact dermatitis from dielectric fluid can be prevented by simple preventive measures such as personal hygiene and health education.

Adult↗

Persistent liver dysfunction among workers at a vinyl chloride monomer polymerization plant.

Thirteen workers with persistent abnormalities in one or more liver function tests (LFT) at a vinyl chloride monomer (VCM) polymerization plant were investigated. Twelve workers were found to have VCM-induced liver dysfunction based on circumstantial evidence. They were employed between 1971 and 1982 when the VCM levels ranged from 1 to 21 p.p.m. After 1982 when the environmental VCM levels were controlled to below 1 p.p.m., no cases of VCM-induced liver dysfunction were detected. In most cases, glutamic pyruvic transaminase was the earliest parameter to be raised. The second most common parameter is serum gamma glutamyl transpeptidase. The latent period ranged from 1 to 13 years. An improvement in their LFT results was shown by 83.3 per cent of workers within 6 months to 2 years after removal from further VCM exposure. For workers who returned to VCM work, their LFT became abnormal again. Liver scans showed hepato and/or splenomegaly in most cases. Liver biopsies on 9 workers were reported as 'non-specific fatty changes' of varying degrees. These observations highlight the need for continual vigilance with environmental monitoring and medical surveillance of VCM-exposed workers.

Adult↗

Study on the health hazards of scrap metal cutters.

Scrap metal cutters seemed to be left out in most preventive programmes as the workers were mainly contract workers. The health hazards of scrap metal cutting in 54 workers from a foundry and a ship breaking plant were evaluated. Environmental sampling showed lead levels ranging from 0.02 to 0.57 mg/m3 (threshold limit values is 0.15 mg/m3). Exposure to lead came mainly from the paint coat of the metals cut. Metal fume fever was not reported although their main complaints were cough and rhinitis. Skin burns at all stages of healing and residual scars were seen over hands, forearms and thighs. 96% of the cutters had blood lead levels exceeding 40 micrograms/100 ml with 10 workers exceeding 70 micrograms/100 ml. None had clinical evidence of lead poisoning. The study showed that scrap metal cutting is a hazardous industry associated with significant lead exposure. With proper medical supervision, the blood lead levels of this group of workers decreased illustrating the importance of identifying the hazard and implementing appropriate medical surveillance programmes.

Adult↗

An outbreak of acneiform eruption in a polyvinyl chloride manufacturing factory.

An outbreak of acneiform eruptions occurred in 14 workers in a polyvinyl chloride (PVC) manufacturing factory. The cause was probably a combination of heat, high humidity and irritation from PVC powder. PVC slurry, scales and powder, to which the workers were exposed, were not comedogenic on rabbit ear. Lowering the temperature and humidity by airconditioning and improving ventilation, together with reduction of dust level at the workplaces, eliminated further outbreak's.

Acne Vulgaris↗