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Biomedical subjects

P Mock

Publications and source records attributed to P Mock.

15 recordsLinked to original sources
PubMed1998

HIV prevalence, risk, and partner serodiscordance among pregnant women in Bangkok. Bangkok Collaborative Perinatal HIV Transmission Study Group.

CONTEXT: Most prior studies of the human immunodeficiency virus (HIV) epidemic in Thailand have focused on commercial sex encounters; however, because the epidemic increasingly concerns stable heterosexual relationships, determining risk factors for this form of transmission is warranted. OBJECTIVES: To determine temporal trends in HIV prevalence, risk factors for HIV seropositivity, and rates of partner serodiscordance for pregnant women in Bangkok, Thailand. DESIGN: Retrospective review of hospital antenatal clinic HIV test results from 1991 through 1996. Baseline demographic and behavioral risk factors for HIV were assessed for subjects enrolled from November 1992 through March 1994. SETTING: Two Bangkok hospitals with routine antenatal clinic HIV counseling and testing. PARTICIPANTS: The HIV-positive pregnant women enrolled in a perinatal HIV transmission study and their partners and HIV-negative pregnant controls. RESULTS: From 1991 through 1996, antenatal clinic HIV seroprevalence increased from 1.0% to 2.3%. On multivariate analysis of data from 342 HIV-positive and 344 HIV-negative pregnant women, more than 1 lifetime sex partner, history of a sexually transmitted disease, and a high-risk sex partner were the most important factors for seropositivity (all P<.001). Twenty-six percent of partners of HIV-positive women were HIV negative. Women reporting more than 1 lifetime sex partner were more likely to have an HIV-negative partner than women reporting only 1 (45% vs 8%; relative risk, 5.5; 95% confidence interval, 3.2-9.5; P<.001); women reporting no high-risk behaviors were less likely to have an HIV-negative partner (10% vs 44%; relative risk, 0.2; 95% confidence interval, 0.1-0.4; P<.001). CONCLUSIONS: Prevalence of HIV in pregnant women has increased steadily in Bangkok from 1991 through 1996. Sex with current partners was the only identified risk exposure for about half (52%) of the HIV-positive women. Although few HIV-positive pregnant women reported high-risk behaviors, more than 1 lifetime partner and a partner with high-risk behavior were strong risk factors for seropositivity. Together with the unexpected finding that one fourth of partners of seropositive pregnant women were seronegative, these data emphasize that women in the general population are at risk for HIV because of the risk behavior of both current and previous partners.

AIDS Serodiagnosis↗
PubMed1998

The apparent late half-life of human chorionic gonadotropin (hCG) after surgical treatment for ectopic pregnancy. A new approach to diagnose persistent trophoblastic activity.

OBJECTIVE: The disappearance kinetic of human chorionic gonadotropin (hCG) follows a biexponential decay with a rapid initial fall followed later by a slow disappearance. This kinetic is characterised by two half-lives: an early and a late. The objective of this study was to determine if and which half-life could be used clinically to detect persistent trophoblast after conservative surgery in patients with ectopic pregnancy. DESIGN: Retrospective analysis of patients having undergone salpingostomy by laparoscopy for an ectopic tubal pregnancy between January 1990 and October 1993. SETTING: Gynaecology Department of an University Hospital. PATIENTS: 104 women with diagnosed tubal ectopic pregnancy were treated by salpingostomy performed under laparoscopy. In seven cases, persistent trophoblast was diagnosed on the basis of plateauing or increasing peripheral hCG values. MAIN RESULTS: From the individual disappearance curves of hCG we calculated the early half-life (early T0.5, from samples obtained between 0 and 48 h postsurgery) and the late half-life (late T0.5, from samples obtained between 2 and 7 days postsurgery). Late T0.5 but not early T0.5 were significantly (P<0.0001 and P=0.416 respectively) longer in women (n =7) in whom a persistent trophoblast was diagnosed. Early T0.5 was dependant on the preoperative value of hCG, whereas late T0.5 was independent. We propose to use late T0.5 as a parameter to follow ectopic pregnancies after treatment.

Chorionic Gonadotropin↗
PubMed1998

Modulation of human chorionic gonadotrophin bioactivity during the first trimester of pregnancy.

The objective of this study was to evaluate the bioactivity of human chorionic gonadotrophin (HCG) during first trimester pregnancy. This was done by means of a retrospective analysis of sera from patients with first trimester normal intrauterine and ectopic pregnancies. Serum samples were obtained from 38 women with amenorrhoea of <10 weeks. From these, 19 had a normal intrauterine pregnancy (IUP) and 19 an ectopic pregnancy (EP). Cases were allocated to either low serum immunoreactive HCG (HCGi), intermediate HCGi or high HCGi concentrations (HCGi <5000 mUI/ml, between 5000 and 40,000 mIU/ml and >40,000 mIU/ml respectively). HCGi and oestradiol were measured by enzyme immunoassays and bioactive HCG by the mouse Leydig cell bioassay. All results were analysed by analysis of variance and unpaired Student's t-test. There was a significant difference between bioactive to immunoreactive HCG ratios (b/i ratio) between the subgroups of low, intermediate and high HCGi concentrations. Lower b/i ratios were found when HCGi concentrations were high (HCG b/i mean +/- SEM: high subgroup, 0.33 +/- 0.07 versus low subgroup: 1.50 +/- 0.12; P < 0.0001). Furthermore, the b/i ratios were inversely correlated with oestradiol (P < 0.0001) and HCGi (P < 0.0001) concentrations but not with gestational age. There was no difference in the b/i ratios when comparing IUP with EP. It is concluded that, in first trimester pregnancies, there is a likely modulation of HCG bioactivity which is inversely correlated with HCGi and oestradiol concentration. The underlying mechanisms and their physiological relevance remain to be elucidated.

Animals↗
PubMed1997

Identification of pro-EPIL and EPIL peptides translated from insulin-like 4 (INSL4) mRNA in human placenta.

Recently, a new member of the insulin gene superfamily termed insulin-like 4 (INSL4) was identified in the human placenta and uterus. The present study investigated whether placenta translates INSL4 mRNA into a putative peptide named early placenta insulin-like (EPIL). Among antibodies elicited against the C chain of pro-EPIL, one antibody (AB7381) was specifically directed against the C chain 59-88 portion, and among those elicited against the A and B chains of EPIL, one antibody (Ab1661) was directed against the A chain 115-139 and the B chain 23-52 portions. Immunohistochemistry based on antibody 7381 to pro-EPIL and antibody 1661 to EPIL demonstrated that the cytotrophoblast from early placenta preferentially expresses the pro-EPIL peptide, whereas the EPIL peptide is expressed by both the cytotrophoblast and the syncytiotrophoblast. At term, the pro-EPIL peptide was detected in villous cytotrophoblast cells, whereas the EPIL peptide was not detected. Moreover, in vitro experiments performed on term placenta showed that the steady state levels of INLS-4 mRNA in the cytotrophoblast are 10 times (one log unit) lower than in the differentiated villous syncytiotrophoblast cells. Taken together, these findings reveal that expression of EPIL peptides in the villous cytotrophoblast is different from that displayed by the syncytiotrophoblast. Finally, these data are the first demonstration that INSL4 mRNA are translated into pro-EPIL and EPIL peptides.

Amino Acid Sequence↗
PubMed1996

Implantable cardioverter defibrillator clinic casualties: inadvertent reprogramming during routine implantable cardioverter defibrillator follow-up.

On one occasion during a busy ICD follow-up clinic, the preceding patient's parameters for rate, PDF, and delay were inadvertently programmed into the subsequent patient's generator using the CPI Programmer Model 2035. This occurred after capacitor reformation, without pressing the "Program" button. The source of this reprogramming error was failure to clear the programmer memory of the previous patient's data, usually achieved by turning the programmer off between patients (or selecting "New Patient" from the menu). At our next ICD follow-up clinic, we purposely did not turn off the programmer between two sets of patients. On both occasions the above finding was repeated and confirmed. These observations indicate the potential for serious reprogramming errors that can occur simply by not clearing the programmer's memory between clinic patients.

Defibrillators, Implantable↗
PubMed1995

PEAPS-Q: a questionnaire to measure the psychosocial effects of having an abnormal pap smear. Psychosocial Effects of Abnormal Pap Smears Questionnaire.

We have developed the Psychosocial Effects of Abnormal Pap Smears Questionnaire (PEAPS-Q) which measures distress experienced by women undergoing follow-up investigation after an abnormal Pap smear result. A thorough literature review and qualitative research resulted in the development of a questionnaire which was tested on 350 women attending a Family Planning New South Wales (FPNSW) clinic. This sample included women at different stages of management after detection of a cervical abnormality: 93 first colposcopy clients and 257 follow-up colposcopy clients. Factor analysis identified four dimensions of distress: experience of medical procedures, beliefs/feelings about cervical abnormality and changes in perception of oneself, worry about infectivity and effect on sexual relationships. Repeatability of the PEAPS-Q was indicated by intra-class correlations of 0.88 overall and at least 0.60 for each scale. Internal consistency was shown by Cronbach's alpha of 0.84 overall and at least 0.72 for each scale. Validity was demonstrated by the correlation of scale scores with the 12-item General Health Questionnaire (GHQ) score of 0.32 (95% CI 0.22-0.41). The PEAPS-Q is a valid, reliable and multidimensional instrument for quantifying distress experienced by women with abnormal Pap smears.

Adult↗
PubMed1995

A prospective cohort study investigating psychosocial predictors of attendance at a mobile breast screening service.

This study aimed to examine whether knowledge, attitudes and concerns predicted attendance at the mobile Breast X-Ray Programme in Sydney. A cohort study design was used, whereby women were surveyed prior to the implementation of the program, and two years later records were checked to determine whether they had attended for screening. Telephone interviews were sought with randomly selected women aged 45 to 70 years living in the central Sydney area (the screening van's catchment area). A total of 285 women was surveyed (response rate: 50 per cent). Of these, 86 (30 per cent) subsequently attended at the mobile van and 199 did not. Attendance did not appear to be related to any of the following factors: knowledge; attitudes; prior experience; perceived susceptibility and morbid concern in relation to breast cancer; the amount of information about screening mammography to which a woman had been exposed. The results are interpreted in light of methodological considerations plus findings from our other research.

Aged↗
PubMed1994

Efficient study designs to assess the accuracy of screening tests.

Evaluating a screening test often requires estimation of test sensitivity and specificity with appropriately narrow confidence intervals and at least cost. If the major cost is the reference ("gold") standard, savings arise from reducing the large number of test negatives that are verified by the reference standard. On the basis of the formulae of Begg and Greenes (Biometrics 1983;39:207-15), the authors determine the optimal sampling strategy for test positives and test negatives to minimize the total sample size that needs to be verified for a given confidence interval width for sensitivity. Unless sensitivity is very high, verifying more test positives and fewer test negatives than would occur with equal sampling fractions is appropriate. For example, if the sensitivity is 0.7 and the specificity is 0.99, the optimal sampling strategy is for 6.2% of those verified to be test positives, compared with 1.7% in the case of equal sampling fractions. At a disease prevalence of 0.01, the 3.3-fold increase in test positives results in a saving of about 15% in the test negatives and 11% in the total verified sample size. Overall, savings are about 50% for a sensitivity of 0.3, but are negligible when sensitivity is greater than 0.8. Optimal sampling strategies for sensitivity do not materially alter confidence intervals for specificity. Figures are presented from which readers can easily obtain the optimal sampling strategy given an estimate of specificity, approximated by the proportion of screenees who are test negative, and the range of likely sensitivity.

Algorithms↗
PubMed1991

Women's perceptions of screening mammography.

A random sample of women in Sydney were interviewed by telephone to determine their knowledge about and attitudes to mammography. A response rate of 56 per cent (628 women) was obtained. While the majority of women had had some experience with breast cancer, knowledge about which age groups were most at risk and treatment alternatives was limited. Only about half of the sample had heard about screening mammography before the survey. However, when a simple explanation was given, 79 per cent expressed a favourable attitude toward it. Only 22 per cent of women thought of themselves as being personally susceptible to breast cancer; the proportion was lower in women over 60 than in those in their 40s. Morbid concern about breast cancer was rare. About a quarter of the sample expressed concern about mammographically induced exposure to radiation. Attitudes and perceptions of personal susceptibility were not associated with knowledge about risks of breast cancer. However, having a favourable attitude and a lack of concern about radiation were associated with previously having heard about screening mammography. Women speaking a language other than English at home and from households where the main income earner was in an unskilled occupation were least likely to have heard of screening mammography. Suggestions for data-based recruitment strategies are discussed.

Attitude to Health↗
PubMed1989

Encouraging attendance at screening mammography: knowledge, attitudes and intentions of general practitioners.

We surveyed a random sample of 200 general practitioners from the Sydney metropolitan area about their attitudes to and knowledge of screening mammography. General practitioners' knowledge about some aspects of screening mammography was found to be limited; only 25% of the sample knew that the risk of breast cancer increases with age and only 30% of the sample knew that the evidence for a reduction in mortality as a result of mammographic screening is weakest for women of less than 50 years of age. Ninety-five per cent of general practitioners were of the opinion that breast self-examination and clinical examination were important for asymptomatic women of more than 45 years of age compared with the 75% of respondents who viewed mammography in the same way. Scores on a scale that was constructed to measure attitudes to mammographic screening showed that 20% of general practitioners had a "very favourable" attitude, and that a further 67% of general practitioners had a "favourable" attitude. No general practitioners had a "very unfavourable" attitude. Eighty-four per cent of general practitioners indicated that they would recommend that their patients attend a free screening-mammography service. Willingness to recommend mammographic screening was predicted by a general practitioner's attitude score. The strongest component of this prediction was a belief that the benefits of screening mammography outweighed the radiation risks. General practitioners need to be supplied with correct information about target groups for screening, so that women in the appropriate age-groups are encouraged to attend screening programmes.

Age Factors↗
PubMed1987

Chylomicrons and chylomicron remnants in coronary artery disease: a case-control study.

Epidemiologic studies of coronary artery disease have largely overlooked the role of triglyceride-rich lipoproteins circulating in the post-prandial state. We have conducted a case-control study in males which examined fasting plasma lipoproteins and lipoproteins circulating 4 h after ingestion of a test meal containing fat and cholesterol. The cases were 82 subjects with coronary artery disease confirmed by angiography, while there were two control groups: one group of 38 'hospital controls' free of significant coronary disease by angiography, and a second group of 61 'workforce controls' free of coronary disease on historical grounds. Mean plasma and LDL cholesterol levels were significantly higher and HDL cholesterol levels were significantly lower in cases than in controls. The apo-B48/apo-B100 ratio in lipoproteins Sf greater than 60 obtained 4 h post-prandially, a relative measure of chylomicron and remnant presence, was significantly higher in cases than in controls. After pooling of all data, the prevalence of coronary artery disease was found to increase progressively with the concentration of plasma cholesterol and triglycerides, total cholesterol/HDL cholesterol ratio and the apo-B48/apo-B100 ratio in Sf greater than 60, the relative risk being highest for total cholesterol/HDL cholesterol ratio. After controlling for the confounding effects of age and other lipid factors via multiple logistic regression, apo-B48/apo-B100 ratio was still a significant predictor of coronary artery disease presence (z = 1.97, P less than 0.05) in a 'dose-response' fashion. The risk of coronary artery disease in the top quartile of apo-B48/apo-B100 distribution was 2.2-fold greater than that for the bottom quartile, after adjustment for the effects of other risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Predictors of surgical wound infection in Australia: a national study.

In July 1984, the first national Australian Nosocomial Prevalence Survey collected data on 12,742 surgical patients from 265 hospitals. This sample represented 59% of public and private hospitals with 50 or more acute-care beds in Australia. The infection control officers at each hospital provided data on patients in a random sample of beds. The over-all surgical wound infection rate was 4.6%. The surgical wound infection rate was twice (5.4%) as high in public than in private (2.8%) hospitals. The infection rates were greater in larger hospitals in both the public and private sector. However, after adjusting for the other predictor factors that are noted below the infection rate did not show any particular pattern for the size of hospital. Clean surgery had a higher (4.8%) infection rate than did clean-contaminated surgery (2.9%). The infection rate for contaminated surgery was 15.0%. Men were found to have nearly twice (6.5%) the infection rate of women (3.4%). Infection rates were lowest in the 15-to-34 years' age-group and highest in those of over 55 years of age. These trends remained even after adjusting for the other risk factors for infection. The cost of surgical wound infections for all hospitals during the year of 1984 was estimated at approximately $60 million. We suggest that a concerted effort should be made to attempt to reduce the infection rate for clean surgery to 1% or less.

Adolescent↗