Biomedical subjects

R Steketee

Publications and source records attributed to R Steketee.

9 recordsLinked to original sources

PubMed1998

Impact of zidovudine use on risk and risk factors for perinatal transmission of HIV. Perinatal AIDS Collaborative Transmission Studies.

OBJECTIVES: To evaluate the impact of perinatal zidovudine use on the risk of perinatal transmission of HIV and to determine risk factors for transmission among women using perinatal zidovudine. DESIGN: Prospective cohort study of 1533 children born to HIV-infected women between 1985 and 1995 in four US cities. METHODS: The association of potential risk factors with perinatal HIV transmission was assessed with univariate and multivariate statistics. RESULTS: The overall transmission risk was 18% [95% confidence interval (CI), 16-21]. Factors associated with transmission included membrane rupture > 4 h before delivery [relative risk (RR), 2.1; 95% CI, 1.6-2.7], gestational age < 37 weeks (RR, 1.8; 95% CI, 1.4-2.2), maternal CD4+ lymphocyte count < 500 x 10(6) cells/l (RR, 1.7; 95% CI, 1.3-2.2), birthweight < 2500 g (RR, 1.7; 95% CI, 1.3-2.1), and antenatal and neonatal zidovudine use (RR, 0.6; 95% CI, 0.4-0.9). For infants exposed to zidovudine antenatally and neonatally, the transmission risk was 13% overall but was significantly lower following shorter duration of membrane rupture (7%) and term delivery (9%). The transmission risk declined from 22% before 1992 to 11% in 1995 (P < 0.001) in association with increasing zidovudine use and changes in other risk factors. CONCLUSIONS: Perinatal HIV transmission risk has declined with increasing perinatal zidovudine use and changes in other factors. Further reduction in transmission for women taking zidovudine may be possible by reducing the incidence of other potentially modifiable risk factors, such as long duration of membrane rupture and prematurity.

Adult↗

PubMed1996

Heterosexual behavior during pregnancy and perinatal transmission of HIV-1. New York City Perinatal HIV Transmission Collaborative Study Group.

OBJECTIVE: To determine the relationship between maternal heterosexual activity during pregnancy and perinatal transmission of HIV-1. DESIGN: A retrospective analysis of 175 New York City HIV-1-seropositive women enrolled during pregnancy or immediately post-partum from 1986 to 1994 in a prospective cohort study. METHODS: Frequency of heterosexual intercourse and condom use during pregnancy was determined from self-report measures. Unprotected intercourse was defined as follows: 'none', consistent condom use or abstinence; 'moderate', inconsistent condom use and fewer than 80 episodes of intercourse; and 'high', inconsistent condom use and 80 or more episodes. RESULTS: The rate of perinatal HIV-1 transmission was 9.1% (four out of 44) among women with no unprotected intercourse during pregnancy, 22.2% (20 out of 90) among those with moderate frequency, and 39.0% (16 out of 41) among those with high frequency (P < 0.01). The relative risk (RR) of perinatal transmission was higher among women with moderate [RR, 2.4; 95% confidence interval (Cl), 0.9-6.7] and high frequency of unprotected sexual intercourse (RR, 4.3; 95% Cl, 1.6-11.8) compared with women with no unprotected sexual intercourse. When potential covariates (maternal injecting drug use, CD4 lymphocyte count, AIDS, zidovudine use, pelvic inflammatory disease or sexually transmitted disease during pregnancy, delivery mode, and extreme prematurity) were included in a logistic regression model (n = 128), the rate of perinatal transmission remained significantly higher among women with any unprotected sexual intercourse during pregnancy. CONCLUSIONS: Data suggest that unprotected sexual intercourse during pregnancy influences perinatal HIV-1 transmission.

Bias↗

PubMed1996

Prospective study of human immunodeficiency virus 1-related disease among 512 infants born to infected women in New York City. The New York City Perinatal HIV Transmission Collaborative Study Group.

OBJECTIVE: To determine the incidence of HIV-1-related clinical findings, mortality and predictors of death in a cohort of HIV-exposed infants followed from birth. METHODS: Data were collected approximately bimonthly during the first and second year of life and used in Kaplan-Meier and Cox proportional hazards survival analyses to predict time to the development of symptoms and death. RESULTS: One hundred sixteen infected and 396 uninfected infants were followed for a median of 26 months at 7 New York City hospitals from 1986 to 1995. Two or more nonspecific HIV-related symptoms, AIDS or death occurred in 83% of infected children by the first year. Fifty infected infants (43%) developed AIDS and 19 (38%) of these had Pneumocystis carinii pneumonia. Estimated median age at AIDS/death was 30 months and 64% of infected children remained alive and AIDS-free at 1 year. Estimated infant mortality among infected children was 160/1000 live births, and median survival after AIDS was 21 months; 55% of infected children survived > 12 months after diagnosis of AIDS. P. carinii pneumonia was the most common cause of death. Although birth CD4 values did not predict AIDS or death, CD4 counts as early as 6 months of age were highly correlated with both. Thirteen (68%) of 19 infants who remained AIDS-free up to 3 to 6 months of age with CD4 count < or = 1500 cells/microliters subsequently developed AIDS vs. 18 (30%) of 61 with CD4 count > 1500 (P = 0.0001). CONCLUSIONS: Most HIV-1-infected infants develop disease in the first year of life. AIDS or death can be predicted by a threshold CD4 count of 1500 cells/microliters at 3 to 6 months of age.

CD4 Lymphocyte Count↗

PubMed1996

Perinatal mortality in rural Malawi.

Reported are the results of a study to assess the prevalence and risk factors for perinatal death among pregnant women in Malawi over the period 1987-90. There were 264 perinatal deaths among the 3866 women with singleton pregnancies (perinatal mortality rate, 68.3 per 1000 births). Among the risk factors for perinatal mortality were the following: reactive syphilis serology, nulliparity, a late fetal or neonatal death in the most recent previous birth, maternal height < 150 cm, home delivery, and low socioeconomic status. Although unexplained perinatal deaths will continue to occur, perinatal mortality can be reduced if its causes and risk factors in a community are given priority in antenatal and intrapartum care programmes. The following interventions could potentially reduce the perinatal mortality in the study population: screening and treating women with reactive syphilis serology; and management from early labour, by competent personnel in a health facility, of nulliparous women and multiparous women who are short or have a history of a perinatal death.

Body Height↗

PubMed1995

Mortality associated with multiple gestation in Malawi.

BACKGROUND: Multiple gestation is associated with increased maternal, perinatal, and infant mortality. The prevalence of multiple gestation varies widely with the highest rates reported among populations in Africa. There have been few population-based studies of the impact of multiple gestation on pregnancy outcomes in sub-Saharan Africa. METHODS: Data from a 1987-1990 prospective study of the effect of malaria chemoprophylaxis among pregnant women on birthweight and mortality of their infants in a rural area of Malawi were used to estimate the prevalence of multiple gestation and to quantify the risk of mortality associated with multiple gestation compared with single gestation. RESULTS: There were 88 (2.2%) multiple gestations among 4049 women. Mortality was high; only 38% of mothers were known to have all their infants survive to 1 year, compared with 74% in singleton gestations. The increased mortality associated with multiple gestation was due to two factors: a higher frequency of low birthweight and a fourfold increase in perinatal mortality among the infants with birthweights > or = 2500 g and among infants with unknown birthweight. We estimated that multiple gestation contributes to 5.5% of the perinatal, 1.2% of the postperinatal, and 11.5% of the maternal deaths in this population. CONCLUSION: Multiple gestation in Malawi contributed to increased perinatal and maternal mortality, but did not increase the risk of mortality after the perinatal period.

Birth Weight↗

PubMed1993

Beyond chloroquine: implications of drug resistance for evaluating malaria therapy efficacy and treatment policy in Africa.

Emphasis on retaining chloroquine as the first-line therapy for Plasmodium falciparum infections in most of sub-Saharan Africa for as long as it remains effective has resulted in widespread reliance on chloroquine in areas where it can have little effect on P. falciparum parasitemia. To address this issue, clinical, parasitologic, and hematologic responses to chloroquine or pyrimethamine/sulfadoxine treatment were assessed among very young children in Malawi (n = 153) and Kenya (n = 73). The median time to resumption of clinical symptoms in chloroquine-treated children was 13.5 days in Malawi and 9.5 days in Kenya. Children treated with pyrimethamine/sulfadoxine maintained clinical improvement and had greater increases in their hemoglobin concentration during the follow-up period than did children treated with chloroquine. Treatment with chloroquine failed to produce either a durable clinical improvement or optimal hematologic recovery. Consequently, chloroquine can no longer be considered adequately effective therapy of clinical P. falciparum malaria in very young children in these areas of Africa.

Child, Preschool↗

PubMed1993

Syphilis-associated perinatal and infant mortality in rural Malawi.

In Mangochi District, a rural area of Malawi, the prevalence of active syphilis was 3.6% among 3591 women who had singleton births and who were negative for human immunodeficiency virus (HIV). Compared with non-syphilitic women, those with active syphilis (positive Venereal Disease Research Laboratory/rapid plasmin reagin tests (titre > or = 1:8) and a reactive microhaemagglutination assay) were more likely to experience stillbirths as well as the early and late neonatal deaths and even postneonatal deaths of their children. Characteristics associated with active syphilis were not very useful in targeting women at high risk of having the condition, which makes universal screening in antenatal programmes the most efficacious way to prevent syphilis-associated morbidity and mortality. The potential for a programme to prevent congenital syphilis in the perinatal, neonatal, and post-neonatal periods is evident. In considering resource allocation to child survival programmes in areas where the prevalence of syphilis is high, officials need to include antenatal syphilis screening, using rapid tests and treatment at the first contact of the mother with the health care system.

Child Welfare↗

PubMed1989

Plasmodium falciparum associated placental pathology: a light and electron microscopic and immunohistologic study.

Pathological changes were studied by light and electron microscopy on term placentas collected in Malawi from 20 P. falciparum infected women (11 primiparas and 9 multiparas). One placenta from an uninfected term primipara and 4 from multiparas were studied as controls. Changes included the presence of parasitized erythrocytes and malarial pigment particles in the intervillous space, excessive syncytial knotting, chronic basal villitis, malarial pigment deposits in the trophoblasts, trophoblastic damage with focal necrosis, partial loss of microvilli, and thickening of the trophoblastic basement membrane. Infected erythrocytes were not seen in the fetal circulation. Severity appeared to correlate with the level of maternal and placental parasitemias, regardless of infant birth weight or placental weight. Differences in the severity of pathological changes between primiparas and multiparas could not be demonstrated. Immunohistochemistry revealed that 45% of the placentas stained strongly for IgG and 15% stained for C3 and for P. falciparum antigens in the trophoblastic cytoplasm and basement membrane.

Animals↗

PubMed1987

Use of enzyme-linked synthetic DNA in diagnosis of falciparum malaria.

Plasmodium falciparum contains a family of 21-base-long repetitive DNA sequences in its genome. A 21-base synthetic DNA oligomer, formerly labelled with phosphorus-32 for autoradiographic detection of P falciparum DNA, was covalently coupled to alkaline phosphatase for histochemical detection. The conjugate (PFR1-AP) detected purified P falciparum DNA with a sensitivity and specificity equal to that of 32P-labelled probes after 2-day exposures. PFR1-AP did not detect host DNA or DNA of other Plasmodium species. In African blood specimens PFR1-AP specifically detected P falciparum infections of 100 parasites/microliter. This sensitive, rapid, nonisotopic probe will allow more widespread use of DNA hybridisation in the diagnosis of malaria.

Alkaline Phosphatase↗