Biomedical subjects

Richard D Semba

Publications and source records attributed to Richard D Semba.

49 records · Page 3Linked to original sources

PubMed2002

Antenatal vitamin A supplementation increases birth weight and decreases anemia among infants born to human immunodeficiency virus-infected women in Malawi.

Vitamin A is essential for immunity and growth. A controlled clinical that involved 697 human immunodeficiency virus (HIV)-infected pregnant women was conducted to determine whether vitamin A prevents anemia, low birth weight, growth failure, HIV transmission, and mortality. Women received daily doses of iron and folate, either alone or combined with vitamin A (3 mg retinol equivalent), from 18-28 weeks' gestation until delivery. In the vitamin A and control groups, respectively, the mean (+/-SE) birth weights were 2895+/-31 g and 2805+/-32 g (P=.05), the proportions of low-birth-weight infants were 14.0% and 21.1% (P=.03), the proportions of anemic infants at 6 weeks postpartum were 23.4% and 40.6% (P<.001), and the respective cumulative proportions of infants who were HIV infected at 6 weeks and 24 months of age were 26.6% and 27.8% (P=.76) and 27.7% and 32.8% (P=.21). Receipt of vitamin A improved birth weight and neonatal growth and reduced anemia, but it did not affect perinatal HIV transmission.

Adult↗

PubMed2002

Vitamin A deficiency and genital viral burden in women infected with HIV-1.

The relation between vitamin A (retinol) deficiency and perinatal transmission of HIV-1, if it exists, might be mediated through an increased viral load in the mother's genital tract. To ascertain whether or not such an association is present, we measured the serum concentration of retinol with high performance liquid chromatography, and correlated the results with concurrent quantified HIV-1 RNA concentrations in cervicovaginal lavage fluid in 301 women infected with the virus. We noted no association between retinol status and genital HIV-1 load. Our findings lend support to those of studies that reported no association between retinol deficiency and perinatal HIV-1 transmission.

Adult↗

PubMed2002

High prevalence of iron deficiency and anemia among female injection drug users with and without HIV infection.

INTRODUCTION: Anemia is associated with increased progression of disease and higher mortality during HIV infection. OBJECTIVE: To determine the prevalence of iron deficiency and iron deficiency anemia among female injection drug users (IDUs) with and without HIV infection. METHODS: Hemoglobin and plasma ferritin were measured in a cross-sectional study of a cohort of female IDUs followed in Baltimore, Maryland. RESULTS: Among 136 HIV-positive and 61 HIV-negative women, the prevalence of anemia was 44.1% and 26.2% ( p <.02), the prevalence of iron deficiency was 37.5% and 42.6% ( p =.49), and the prevalence of iron deficiency anemia was 20.6% and 14.7% ( p =.33), respectively. The overall prevalence of hepatitis C infection was 90.5%. Iron deficiency anemia accounted for 46.7% and 56.1% of the anemia among HIV-positive and HIV-negative female IDUs. CONCLUSIONS: Iron deficiency accounts for about half of the anemia among female IDUS. Although iron supplementation is indicated for anemia patients, such treatment should be approached with caution in women coinfected with HIV and hepatitis C virus, because iron supplementation and overload have been associated with increased progression of HIV infection, worsening of hepatitis C virus infection, and higher mortality.

Anemia, Iron-Deficiency↗

PubMed2002

Micronutrient malnutrition and the pathogenesis of malarial anemia.

Malaria is a leading cause of morbidity and mortality worldwide, and anemia is a common and sometimes serious complication of Plasmodium falciparum infection. Although micronutrient malnutrition is usually highly prevalent in malaria endemic areas, the contribution of micronutrient deficiencies to malarial anemia is often overlooked. Recent investigation suggests that micronutrients such as vitamin A, vitamin E, and zinc, may improve the morbidity of malaria through immune modulation and alteration of oxidative stress. Micronutrients are also involved in the pathogenesis of anemia and likely play a role in malarial anemia, but many clinical trials have not specifically addressed the impact of micronutrient supplementation on malarial anemia. Further work is needed to assess the effect of both clinic and community-based micronutrient interventions on malarial anemia in infants, children, and pregnant women.

Adolescent↗

PubMed2002

Low serum vitamin d does not predict new disability or loss of muscle strength in older women.

OBJECTIVES: To determine whether serum levels of 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone (PTH) predict accelerated decline in muscular strength or onset of new disability in mobility and upper extremity functioning over a 3-year follow-up. DESIGN: A community-based prospective cohort study. PARTICIPANTS: Six hundred twenty-eight moderately to severely disabled women aged 65 and older living in the community. MEASUREMENTS: Subjects were divided into three groups of baseline 25(OH)D serum levels (deficiency: <25 nmol/L; low normal: 25-52 nmol/L; high normal: > or =53 nmol/L) and into tertiles of PTH levels. Objective performance measures (hip flexor, knee extensor, and grip strengths; walking speed; and time for repeated chair stands) and disability in activities involving mobility and upper extremity function were assessed at baseline and every 6 months for 3 years. Decline in performance measures and onset of new disability were compared between 25(OH)D and PTH groups using random effects models and proportional hazards models, respectively, while adjusting for age, race, education, body mass index, baseline performance, and chronic conditions. RESULTS: The annual rate of decline over 3 years in muscular strength, walking speed, and time to perform repeated chair stands was similar across 25(OH)D groups. We observed a nonsignificantly faster decline in proximal muscle strength and walking speed with increasing PTH levels. There was no association for either measure between serum levels and the risk of incident disability in activities relating to mobility and upper extremity function. CONCLUSION: This study does not support the hypothesis that vitamin D deficiency is associated with loss in muscular strength and decline in mobility and upper extremity functioning over time in older women who were moderately to severely disabled at baseline.

Age Factors↗

PubMed2002

Iron deficiency anemia is highly prevalent among human immunodeficiency virus-infected and uninfected infants in Uganda.

Although anemia is a common finding among human immunodeficiency (HIV)-infected infants in sub-Saharan Africa, the factors contributing to the pathogenesis of anemia have not been well characterized. We sought to characterize the relative contribution of iron deficiency and chronic disease to the anemia among infants. Hemoglobin, ferritin, erythropoietin, tumor necrosis factor-alpha (TNF-alpha), neopterin, CD4(+) lymphocyte count and plasma HIV load were measured in 165 HIV-infected and 39 uninfected 9-mo-old infants seen in an outpatient pediatric clinic in Kampala, Uganda. Among HIV-infected and uninfected infants, the prevalence of anemia (hemoglobin < 110 g/L) was 90.9 and 76.9%, respectively (P = 0.015), and the prevalence of iron deficiency anemia (hemoglobin < 110 g/L and ferritin < 12 microg/L) was 44.3 and 45.4%, respectively (P = 0.92). The relatively higher prevalence of anemia among HIV-infected infants was attributed to the anemia of chronic disease. Among infants with and without iron deficiency, the fitted regression line was log(10) plasma erythropoietin = 2.86 - 0.016.hemoglobin, and log(10) plasma erythropoietin = 4.11 - 0.028.hemoglobin, respectively, with a difference in the slope of the regression lines between log(10) erythropoietin and hemoglobin among infants with and without iron deficiency (P = 0.049). Infants in Uganda have an extremely high prevalence of anemia, and nearly half of the anemia is due to iron deficiency. The erythropoietin response to anemia appears to be upregulated among infants with iron deficiency.

Anemia, Iron-Deficiency↗

PubMed2002

Erythropoietin in human milk: physiology and role in infant health.

Human milk contains substantial concentrations of erythropoietin, a hormone best known for its role in the regulation of erythropoiesis. Recent studies show that erythropoietin receptors are widely distributed in human tissues, including the gastrointestinal tract, endothelial cells, spinal cord, and brain, suggesting that erythropoietin plays a wider role in infant development. Mammary epithelial cells contribute to the production of erythropoietin in human milk, and erythropoietin concentrations appear to rise slowly in human milk during the first few months of lactation. Current data suggest that erythropoietin in human milk may play a pleiomorphic role in erythropoiesis, neurodevelopment, maturation of the gut, apoptosis, and immunity in the infant.

Adult↗

PubMed2002

Risk factors and cumulative incidence of anaemia among HIV-infected injection drug users.

Risk factors for anaemia and cumulative incidence of anaemia were examined in a longitudinal cohort study of 622 injection drug users (IDUs) (8885 visits) in Baltimore, Maryland, from 1988 to 2000. At enrollment, 19.6% subjects were anaemic (16.1% of men and 30.5% of women, P<0.0001) and 8.4% had microcytic anaemia (6.7% of men and 14.0% of women, P=0.006). Cumulative incidence of anaemia was 82.2% (87.9% of men and 100% of women, P<0.0001) during a median of 7.5 years follow-up. Factors associated with anaemia included age (per 5 year increase, odds ratio (OR)=1.22; 95% confidence interval (CI): 1.10, 1.36), female gender (OR=1.62; 95% CI: 1.16, 2.27), CD4+ lymphocyte count <200 cells/microl (OR 1.85; 95% CI: 1.52, 2.24), weight loss (OR 1.55; 95% CI: 1.26, 1.91), oral thrush (OR 1.53; 95% CI: 1.21, 1.94), Mycobacterium avium complex infection (OR 1.30; 95% CI: 1.04, 1.64), and zidovudine use (OR 1.24; 95% CI: 1.04, 1.48). Higher body mass index (OR 0.92; 95% CI: 0.88, 0.95) and marijuana use (OR 0.75; 95% CI: 0.61, 0.92) were associated with a lower risk of anaemia. The cumulative incidence of anaemia is high among IDUs, and women are at highest risk of anaemia.

Adult↗

PubMed2002

Relationship between carotenoids and anaemia during acute uncomplicated Plasmodium falciparum malaria in children.

A clinic-based cohort study in Kampala, Uganda, was conducted to examine the relationship between severe malarial anaemia and plasma micronutrients. Plasma carotenoids, retinol, vitamin E, and four trace metal concentrations were measured at enrollment and seven days later in 273 children, aged 1-10 year(s), with acute, uncomplicated Plasmodium falciparum malaria. Concentrations of plasma provitamin A carotenoids (p < 0.0001), non-provitamin A carotenoids (p < 0.0001), retinol (p < 0.0001), all four trace elements (all p < 0.001), and vitamin E (p < 0.0001) rose significantly by day 7 among children without severe anaemia (haemoglobin 70 g/L). There was no change in provitamin A carotenoids (p = 0.24) among children with severe anaemia (haemoglobin <70 g/L), whereas non-provitaminAcarotenoids (p < 0.0001), retinol (p < 0.0001), and vitamin E (p = 0.011) increased. These observations also support the hypothesis that the use of provitamin A carotenoids increases during malaria infection.

Acute Disease↗

PubMed2001

Prevalence and cumulative incidence of and risk factors for anemia in a multicenter cohort study of human immunodeficiency virus-infected and -uninfected women.

We conducted a longitudinal study of 797 human immunodeficiency virus (HIV)-positive women (7732 visits) and 389 HIV-negative women (3651 visits) to characterize anemia. At enrollment, the prevalence of anemia was 28.1% among HIV-positive women and 15.1% among HIV-negative women (P<.0001), and during follow-up the cumulative incidence of anemia was 74% and 48%, respectively (P<.0001). Risk factors for anemia were African American race (odds ratio [OR], 2.15; 95% confidence interval [CI], 1.73-2.69), age (per 5-year increase; OR, 1.12; 95% CI, 1.03-1.21), body mass index (OR, 0.96; 95% CI, 0.94-0.97), history of pneumonia (OR, 1.41; 95% CI, 1.20-1.65), oral candidiasis (OR, 1.42; 95% CI, 1.22-1.66), CD4+ lymphocyte count <200 cells/microL (OR, 1.68; 95% CI, 1.46-1.94), history of fever (OR, 1.42; 95% CI, 1.13-1.80), and zidovudine use (OR, 1.14; 95% CI, 1.01-1.30). Anemia was common and associated with an increased risk of death (hazards ratio, 1.64; 95% CI, 1.21-2.23) among HIV-positive women.

Adult↗

PubMedDate not supplied

T cell subsets and mortality in older community-dwelling women.

The relationship between specific T cell subset alterations and mortality has not been well characterized in older adults. The specific aim was to determine whether specific T cell subsets are associated with an increased risk of death. We conducted a case-control study of T cell subsets (CD4+ and CD8+ T cells, and subsets of these cells defined by expression or non-expression of CD28, CD45RA, and CD45RO) nested within two complementary prospective cohorts of women aged 65 and over living in the community, the Women's Health and Aging Studies (WHAS). Cases consisted of 61 women who died during 5 years of follow-up, and controls consisted of 61 women matched by age, frailty, and morbidities who survived during 7 years of follow-up. There were no significant differences between cases and controls in any of the T cell subsets studied. When analyses were stratified by frailty status, these data suggest that CD8+CD28- lymphocyte counts were significantly higher among women who were frail compared with pre-frail and non-frail women.

Aged↗

PubMedDate not supplied

Measles blindness.

Measles remains a major problem in developing countries, where it affects an estimated 30 million children a year and causes up to one million deaths annually. Measles blindness is the single leading cause of blindness among children in low income countries, accounting for an estimated 15,000 to 60,000 cases of blindness per year. There is a close synergism between measles and vitamin A deficiency that can result in xerophthalmia, with corneal ulceration, keratomalacia, and subsequent corneal scarring or phthisis bulbi. High-dose oral vitamin A supplementation is recommended for all children with measles in developing countries. Higher measles immunization coverage to interrupt measles transmission and interventions aimed at improving vitamin A nutriture of children are the main strategies to prevent measles blindness.

Blindness↗

PubMedDate not supplied

The trachoma menace in the United States, 1897-1960.

Although largely considered a problem of developing countries today, trachoma was once extremely common in parts of the United States and accounted for a large proportion of blindness. Under an act signed by President Woodrow Wilson in June 1913, a substantial part of the U.S. Public Health Service budget was earmarked to fight trachoma. Numerous trachoma surveys revealed the presence of a "trachoma belt" across the mid United States, and the prevalence of trachoma reached as high as 50-90% among school children on some Indian reservations. Crowding, poverty, and lack of clean water and hygiene were identified as risk factors for trachoma. Measures taken to combat trachoma included isolation schools for infected children, special government trachoma hospitals and field clinics, screening of immigrants to the U.S., improvements in hygiene and sanitation, and antibiotic therapy. The Indian Health Service utilized radical eyelid surgery with reportedly disastrous consequences. Prevalence surveys show a clear decline in trachoma in the U.S. during the twentieth century.

History, 19th Century↗