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Biomedical subjects

M Cheang

Publications and source records attributed to M Cheang.

16 recordsLinked to original sources
PubMed1992

Human immunodeficiency virus type 1 infection in women attending a sexually transmitted diseases clinic in Kenya.

A cross-sectional study was conducted among women attending a sexually transmitted diseases clinic in Nairobi, kenya, to determine the prevalence of and associated risk factors for human immunodeficiency virus (HIV) type 1 infection. HIV-1 antibody was detected in 13.8% of 600 women. This virus was found most frequently in prostitutes (odds ratio [OR], 7.2), in women reporting a history of genital ulcers (OR, 2.3), and in those with a current diagnosis of genital ulcers (OR, 5.1). Lifetime duration of oral contraceptive use was significantly greater in HIV-1-positive women. Multivariate analysis revealed an association between genital ulcers and HIV-1 infection (OR, 3.8). The strongest association for HIV-1 infection, however, occurred with genital ulcers in combination with the use of oral contraceptives (OR, 25.7).

Adult↗
PubMed1992

Efficacy of Listerine, Meridol and chlorhexidine mouthrinses as supplements to regular tooth cleaning measures.

The anti-plaque, anti-gingivitis and anti-microbial efficacies of a phenolic compound (Listerine) and 2 different amine/stannous fluoride mouthwashes (Meridol I, II) were compared when these solutions were used in addition to usual tooth cleaning. A placebo preparation was utilized as a negative control and a chlorhexidine solution as a positive control in this double-blind study. After professional tooth cleaning, 49 volunteers continued their habitual, self-performed and non-supervised oral hygiene for a period of 2 weeks, in order to have a more standard baseline. At day 0, they began to rinse twice daily with 1 of the 5 mouthwashes. After 3 weeks of rinsing, plaque indices remained the lowest in the chlorhexidine and the Meridol I groups, while subjects using Listerine or Meridol II demonstrated similar indices significantly lower than that of individuals rinsing with the placebo solution. Through this period, the gingival index scores were similar in the Meridol, Listerine and chlorhexidine groups. At day 21, the mean GI scores in the chlorhexidine group were significantly lower than the scores in the placebo group. The plaque vitality scores showed a bacterial effect in vivo of chlorhexidine and, to a lesser extent, of the Meridol solutions. No substantial evidence of an antibacterial effect in vivo was found for Listerine. This study has demonstrated that when mouthrinses are used to supplement habitual mechanical oral hygiene, chlorhexidine remains the most powerful solution. Furthermore, it was also shown that a combination of habitual self-performed and non-supervised oral hygiene with Meridol or Listerine is more beneficial for plaque control than the use of mechanical oral hygiene alone.

Adult↗
PubMed1992

A role for prostacyclin in bruising symptomatology.

The relationship between bleeding and bruising and the production of prostacyclin and thromboxane was assessed in children who were to have a tonsillectomy and/or an adenoidectomy. Eicosanoids in the blood oozing from the bleeding time incision were measured and correlated with the reported frequency of bruising and epistaxis. A striking association (P = .0003) between prostacyclin production and the frequency of bruising was found; children reporting bleeding at least biweekly had the highest prostacyclin synthesis. Successively lower levels of the prostacyclin metabolite, 6-keto-prostaglandin F1 alpha, were found in children reporting less frequent bruising. Prostacyclin production in bleeding time blood was also correlated inversely with systolic blood pressure and hemoglobin level, although neither of these variables could explain the association between prostacyclin production and bruising. There was no correlation between thromboxane formation, systolic blood pressure, hemoglobin level, age, or bleeding time and the frequency of bruising. The ratio of thromboxane B2 to 6-keto-prostaglandin F1 alpha was correlated inversely with the length of the bleeding time (P = .016). It is concluded that vascular prostacyclin production may have a role in bruising symptomatology. It is suggested that prostacyclin formed at the injured vessel surface collects within the first few seconds after injury inside the tissue space at the site of the bruise and, by influencing the formation of the platelet/fibrin plug and/or the leakage of blood from the vessels, plays a significant role in modifying the development of bruising.

6-Ketoprostaglandin F1 alpha↗
PubMed1991

How long should catheter-acquired urinary tract infection in women be treated? A randomized controlled study.

OBJECTIVE: To determine the optimal management of catheter-acquired bacteriuria after short-term catheter use in women. PATIENTS: Asymptomatic patients (119) with catheter-acquired bacteriuria were randomly assigned to receive no therapy, a single dose (320-1600 mg) of therapy with trimethoprim-sulfamethoxazole, or 10 days (160-800 mg twice daily) of therapy. Thirty-two patients with lower tract symptoms alone received a single dose or 10 days of therapy, and 10 patients with upper tract symptoms or signs received 10 days of therapy. MAIN RESULTS: The mean and median durations of catheter use were 6 and 4 days, respectively. Bacteriuria resolved within 14 days without therapy in 15 of 42 (36%; 95% CI, 21% to 51%) asymptomatic patients. Seven of the remaining patients developed symptoms. Single-dose therapy resolved infection in 30 of 37 patients (81%; CI, 68% to 94%); 10 days of therapy resolved infection in 26 of 33 (79%; CI, 65% to 93%). For patients with lower tract symptoms alone, resolution rates with single-dose therapy or 10 days of therapy were similar (11 of 14 [79%] and 13 of 16 [81%], respectively). Ten days of therapy resolved infection in 6 of 9 (67%) patients with upper tract symptoms. Infection was resolved more often in women who were less than or equal to 65 years than in older women (62 of 70 [89%] versus 24 of 39 [62%]; P less than 0.001). Bacteriuria resolved spontaneously more frequently in younger (14 of 19 [74%] compared with 1 of 23 older women [4%]; P less than 0.001). Single-dose therapy resolved infection in 31 of 33 (94%) patients who were less than or equal to 65 years. CONCLUSIONS: Asymptomatic bacteriuria after short-term catheter use frequently becomes symptomatic and should be treated. For asymptomatic patients and patients with lower tract symptoms alone, single-dose therapy was as effective as 10 days of therapy; it was very effective in women who were less than or equal to 65 years. Bacteriuria resolved spontaneously within 14 days after catheter removal more commonly in women who were less than or equal to 65 years and both types of therapy were less effective in older women.

Adult↗
PubMed1991

Computer assisted analysis of hand radiographs in infantile hypophosphatasia carriers.

Hand radiographs of 49 carriers of infantile hypophosphatasia and 67 non-carriers were evaluated using two Apple IIe Computer Programs and an Apple Graphics Tablet. CAMPS (1) was used to determine the bone lengths and calculate the metacarpophalangeal profiles. A newly developed program (ADAM) was used to determine bone density based on percent cortical area of the second metacarpal. Carriers of infantile hypophosphatasia had significantly less dense bones.

Adolescent↗
PubMed1991

Cofactors in male-female sexual transmission of human immunodeficiency virus type 1.

In a study of human immunodeficiency virus type 1 (HIV-1)-uninfected African prostitutes, 83 (67%) of 124 seroconverted to HIV-1. Oral contraceptive use (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.1-8.6; P less than .03), genital ulcers (mean annual episodes, 1.32 +/- 0.55 in seroconverting women vs. 0.48 +/- 0.21 in seronegative women; P less than .02) and Chlamydia trachomatis infections (OR, 3.6; CI, 1.3-11.0; P less than .02) were associated with increased risk of HIV-1 infection. Condom use reduced the risk of HIV-1 infection (OR, 0.11; CI, 0.05-0.27; P less than .0001). Stepwise logistic regression analysis confirmed independent associations between HIV-1 infection and oral contraceptive use, condom use, genital ulcers, and C. trachomatis. The presence of other sexually transmitted diseases may in part explain the heterosexual HIV-1 epidemic in Africa and may represent important targets for intervention to control HIV-1 infection.

Adult↗
PubMed1991

An analysis of occupational blood lead trends in Manitoba, 1979 through 1987.

BACKGROUND: While regulations for workplace lead exposure become more strict, their effectiveness in decreasing blood lead concentrations and the method by which this is attained have not been evaluated. METHODS: An analysis was conducted of 10,190 blood lead samples from employees of 10 high-risk workplaces collected in Manitoba, 1979-87, as part of regulated occupational surveillance. RESULTS: A significant decrease in blood lead concentrations was observed overall as well as for each individual company. A 1979 government regulation to reduce blood lead to below 3.38 mumol/L (70 micrograms/dl) was followed by a drop in blood lead concentrations; a 1983 order to reduce blood leads to below 2.90 mumol/L (60 micrograms/dl) was not followed by such a drop. Longitudinal analysis by individual workers suggested that companies were complying by use of administrative control, i.e., removing workers to lower lead areas until blood lead levels had fallen, then returning them to high lead areas. CONCLUSION: Focusing upon blood lead as the sole criterion for compliance is not effective; regulations must specifically require environmental monitoring and controls. Biological surveillance serves as "back-up" to environmental surveillance and this database illustrates the usefulness of a comprehensive centralized surveillance system.

Air Pollutants, Occupational↗
PubMed1990

Quantitative analysis of the effect of freezing on donor sperm motion kinetics.

One hundred ninety-two semen specimens from 14 donors were analyzed on a CellSoft Semen Analyzer (CRYO Resources, New York, NY) before and after freezing. Mean post-thaw motility decreased by 52%. Correlation of the percent decrease in post-thaw versus prefreeze motility was significant but of poor predictive value. Comparisons of the percent change in post-thaw motility and sperm motion kinetics between four discrete ranges of prefreeze motility (32% to 66%, 67% to 76%, 77% to 84%, 85% to 94%) revealed that the effect of freezing on sperm cell survival was equivalent between all ranges. However, significant differences occurred between these ranges for curvilinear velocity, straight line velocity, and mean amplitude of lateral head displacement but not for linearity nor beat cross frequency. All correlations between prefreeze and post-thaw motion variables were significant but closest for curvilinear velocity and straight line velocity. Furthermore, correlations of prefreeze versus post-thaw velocity measurements were strongest for those cells within the 65% to 85% range of prefreeze motility. We suggest that sperm survival is independent of prefreeze motility. However, velocity kinetics appear stable after freezing for those specimens that had an initial motility of 65% to 85%.

Analysis of Variance↗
PubMed1990

Maternal gonococcal infection as a preventable risk factor for low birth weight.

With the objective of determining if specific sexually transmitted diseases (STDs) are associated with prematurity (birth weight less than or equal to 2500 g and gestational age less than or equal to 36 weeks), a case-control study was conducted to evaluate women for serologic evidence of syphilis and human immunodeficiency virus infection and microbiologic evidence of cervical infection with Neisseria gonorrhoeae, Chlamydia trachomatis, and Haemophilus species and vaginal infection with genital mycoplasma, Streptococcus agalactiae, and Enterobacteriaceae. Gram stains of vaginal secretions were evaluated for bacterial vaginosis. Among 166 cases and 175 controls, infection with N. gonorrhoeae was associated with preterm birth. Four percent of controls and 11% of cases were infected with N. gonorrhoeae (odds ratio 2.9, 95% confidence interval 1.2-7.2). This association was independent of age, rupture of membranes, and hypertension. Other STDs were not associated with preterm birth. The attributable risk of gonococcal infection was 14%. Gonococcal infection appears to be responsible for a substantial proportion of premature births and is theoretically preventable by antenatal case detection and treatment.

Adult↗
PubMed1990

Possible association of rare autosomal folate sensitive fragile sites and idiopathic mental retardation: a blind controlled population study.

The expression of folate sensitive fragile sites (FS) was assessed in cord blood lymphocyte cultures obtained from 790 newborns (NB) and in peripheral blood lymphocyte cultures from 326 institutionalized mentally retarded residents (MR). The mean rate of expression of common FS and the occurrence of rare FS was significantly higher in the MR population. Age, sex and history of chronic medication use did not appear to influence common FS expression in the MR population, 3/790 (0.38%) NB and 5/326 (1.53%) MR exhibited rare autosomal folate sensitive FS, a 4-fold difference in incidence (P = 0.009, Poisson test). Four of the five MR who expressed rare FS were considered to have idiopathic MR (4/179 or 2.2%). The occurrence of rare FS in 1/147 (0.68%) MR with known etiology is not significantly different from the frequency of occurrence in the NB population (P = 0.428, Poisson test). In this population, rare FS appear to be overrepresented in the idiopathic etiology MR group.

Abnormalities, Multiple↗
PubMed1989

Female to male transmission of human immunodeficiency virus type 1: risk factors for seroconversion in men.

To determine the frequency and risk factors for female to male sexual transmission of human immunodeficiency virus type 1 (HIV-1), a prospective study was carried out in 422 men who had acquired a sexually transmitted disease (STD) from a group of prostitutes with a prevalence of HIV-1 infection of 85%. The initial seroprevalence of HIV among the men was 12%. 24 of 293 (8.2%) initially seronegative men seroconverted to HIV-1. Newly acquired infection was independently associated with frequent prostitute contact (risk ratio 3.2, 95% confidence interval 1.2-8.1), with the acquisition of genital ulcer disease (risk ratio 4.7, 95% confidence interval 1.3-17.0), and with being uncircumcised (risk ratio 8.2, 95% confidence interval 3.0-23.0). 96% of documented seroconversions occurred in men with one or both of the latter two risk factors. In a subgroup of 73 seronegative men who reported a single prostitute sexual contact, the frequency of HIV-1 infection was 8.2% during 12 weeks of observation. No man without a genital ulcer seroconverted. A cumulative 43% of uncircumcised men who acquired an ulcer seroconverted to HIV-1 after a single sexual exposure. These data indicate an extremely high rate of female to male transmission of HIV-1 in the presence of STD and confirm a causal relation between lack of male circumcision, genital ulcer disease, and susceptibility to HIV-1 infection.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Chronic respiratory disorders related to farming and exposure to grain dust in a rural adult community.

In a survey of chronic respiratory symptoms and airflow obstruction of a rural population aged 20-65 years, the effects of both farming and, in particular, the exposure to grain dust on the respiratory health of the people was examined. Of the 1,892 subjects (82% of the eligible population) studied, 924 were males and 968 females, with half living in the town. Three groups were identified: current, former, and never farmers. Almost all current farmers were exposed to grain for, on average, 2 months a year. There was no difference in atopic status between the groups. While there was a strong association between most symptoms and smoking, there was no association between symptoms and exposure to grain and farming category once age and smoking had been taken into account. Results of this study suggest that farmers do not have chronic respiratory symptoms or impairment of lung function because of their exposure to grain dust. Lung function of former farmers might have been affected by farming, and this may reflect more involvement with livestock in the past.

Adult↗
PubMed1989

Diminished responsibility--a psychiatric viewpoint.

Diminished responsibility is based on the notion that mental disorder may make a person only partially accountable for his act in the killing of another person. For this plea to succeed it has to be shown that an accused has to be suffering from such an abnormality of mind that his responsibility for the action is substantially diminished. As these concepts of abnormality of mind and criminal responsibility do not fit easily into psychiatric classification of mental disorders, nine senior psychiatrists who regularly attend court as expert witnesses were surveyed and their viewpoints about mental abnormality and diminished responsibility were elected.

Attitude of Health Personnel↗
PubMedDate not supplied

Maternal and neonatal neutralizing antibody titers to selected enteroviruses.

Neutralizing antibody titers were determined at term for 98 matched mothers' serum and neonatal cord blood pairs, to coxsackieviruses B2, B3, B4 and B5 and to echovirus 11. The reciprocal of the geometric mean titers of maternal sera were, respectively, 15.3, 18.1, 53.5, 14.1 and 11.4. The geometric mean titers of cord sera were statistically lower for coxsackie B5 and echovirus 11 (P less than 0.031 and p less than 0.005, respectively) than those in maternal sera. The percentage of neonates born with antibody titers less than 1:10 to coxsackieviruses B2, B3, B4 and B5 and echovirus 11 ere 49, 37, 17, 53 and 69%. Thus a large percentage of neonates in our community are born with low titers of enterovirus-neutralizing antibody, which for some infants may be disproportionately lower than maternal titers to selected enteroviruses. Commercially available immune serum globulin contains high titers of antibody to these enteroviruses and may be a useful means of passive antibody acquisition in susceptible neonates at risk for enterovirus infections. However, a single dose of immune serum globulin intramuscularly produced little change in circulating neutralizing antibodies to coxsackie B4 and echovirus 11 in seven neonates.

Adult↗
PubMedDate not supplied

Adverse effects of the salazopyrine metabolite sulphapyridine on female fertility in the rat.

Salazopyrine, a common therapy for inflammatory bowel disease, is known to have a reversible antifertility effect in men and male rats via its metabolite, sulphapyridine. To determine if there is an adverse effect in females, 20 mature Sprague-Dawley rats were assigned to a treatment (400 mg/kg sulphapyridine daily), or a control group. After three estrous cycles of treatment, the rats were bred to males of proven fertility. When killed at 10 days gestation, there was a significant reduction in the proportion of fertilized oocytes between control (112/174) and treatment (81/212) groups (chi-square = 26.16, d.f. = 1, P less than .00001). These findings suggest an adverse effect of sulphapyridine on female fertility.

Animals↗