Expression of cytochromes P450 1A1 and 1B1 in human lung from smokers, non-smokers, and ex-smokers.

Cytochromes P450 1A1 and 1B1 are known to bioactivate procarcinogens such as polycyclic aromatic hydrocarbons (PAHs) found in cigarette smoke and are inducible via an Ah receptor-mediated mechanism. The aim of this study was to examine the levels of expression of CYP1A1 and CYP1B1 in samples of lung from smokers (n = 18), non-smokers (n = 7), and ex-smokers (n = 7). Using immunoglobulin preparations of highly specific polyclonal antibodies and immunoblot analysis of microsomes from lung tissues, we determined the specific content for CYP1A1 and CYP1B1.

Investigation of the association of esophageal carcinoma with human papillomaviruses.

The role of human papillomavirus (HPV) in esophageal cancers was evaluated in patients seen at Johns Hopkins University Hospital. Frozen esophageal tumor tissues from 22 cases with squamous cell carcinoma (SCC) and 24 cases with adenocarcinoma (AC), diagnosed between 1988 and 1998, were assayed for HPV sequences by reverse line blot polymerase chain reaction. HPV sequences (HPV-54) were detected in a single specimen; the other 45 specimens were negative.

A measurement error model for time-series studies of air pollution and mortality.

One barrier to interpreting the observational evidence concerning the adverse health effects of air pollution for public policy purposes is the measurement error inherent in estimates of exposure based on ambient pollutant monitors. Exposure assessment studies have shown that data from monitors at central sites may not adequately represent personal exposure. Thus, the exposure error resulting from using centrally measured data as a surrogate for personal exposure can potentially lead to a bias in estimates of the health effects of air pollution.

Social and psychological influences on HIV preventive behaviors of youth in Haiti.

Purpose: To examine HIV/AIDS prevention-related sexual behaviors and identify potential predictors of those behaviors among youth living in Haiti.

Methods: Data were gathered from a cross-sectional survey conducted with 845 youth, aged 15-19 years, attending 12 primary and/or secondary schools. A subsample of the 491 students who were sexually active comprised the study sample.

Pro12Ala of the peroxisome proliferator-activated receptor-gamma2 gene is associated with lower serum insulin levels in nonobese African Americans: the Atherosclerosis Risk in Communities Study.

Recent research suggests that the Pro12Ala variant in peroxisome proliferator-activated receptor-gamma2 (PPAR-gamma2) is associated with diabetes- and obesity-related traits, and that its effects may be modified by obesity status. We characterized this variant in a population-based sample of 1,441 middle-aged African-American individuals with respect to diabetes-, obesity-, and other cardiovascular-related traits, both cross-sectionally and prospectively. The overall frequency of Ala12 was 1.

Counseling and motivational videotapes increase duration of breast-feeding in African-American WIC participants who initiate breast-feeding.

Objective: To evaluate the relative effects introducing motivational videotapes and/or peer counseling in Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) clinics serving African-American women have on breast-feeding duration.

Design: Experimental intervention study. Pregnant women were enrolled at or before 24 weeks gestation and were followed up until postpartum week 16.

Overexpression, purification, and characterization of the periplasmic space thiamin-binding protein of the thiamin traffic ATPase in Escherichia coli.

Thiamin (Vitamin B(1)) transport in Escherichia coli occurs by the superfamily of traffic ATPases in which the initial receptor is the periplasmic binding protein. We have cloned the periplasmic thiamin-binding protein (TBP) of the E. coli periplasmic thiamin transport system and purified the overexpressed protein to apparent homogeneity.

Thiamine transport in Escherichia coli: the mechanism of inhibition by the sulfhydryl-specific modifier N-ethylmaleimide.

Active transport of thiamin (vitamin B(1)) into Escherichia coli occurs through a member of the superfamily of transporters known as ATP-binding cassette (ABC) transporters. Although it was demonstrated that the sulfhydryl-specific modifier N-ethylmaleimide (NEM) inhibited thiamin transport, the exact mechanism of this inhibition is unknown. Therefore, we have carried out a kinetic analysis of thiamin transport to determine the mechanism of inhibition by NEM.

Effect of student involvement on patient perceptions of ambulatory care visits: a randomized controlled trial.

Objective: To determine if patient satisfaction with ambulatory care visits differs when medical students participate in the visit.

Design: Randomized controlled trial.

Setting: Academic general internal medicine practice.

Calibration and random variation of the serum creatinine assay as critical elements of using equations to estimate glomerular filtration rate.

Equations using serum creatinine level, age, sex, and other patient characteristics often are used to estimate glomerular filtration rate (GFR) in both clinical practice and research studies. However, the critical dependence of these equations on serum creatinine assay calibration often is overlooked, and the reproducibility of estimated GFR is rarely discussed. We address these issues in frozen samples from 212 Modification of Diet in Renal Disease (MDRD) study participants and 342 Third National Health and Nutrition Examination Survey (NHANES III) participants assayed for serum creatinine level a second time during November 2000.

Molecular changes in glutamatergic synapses induced by Pb2+: association with deficits of LTP and spatial learning.

What are the molecular bases for the neurotoxicity that occurs after developmental exposure to low levels of Pb2+, and are these effects persistent and detrimental in adults? Our inability to understand specific mechanisms behind Pb2+ neurotoxicity has long been one of many problem areas of this preventable childhood disease. The sensitivity of the developing brain to Pb2+-induced neurotoxicity is an outcome of the many unique characteristics that comprise the developing central nervous system. The developing brain can be exposed to significant concentrations of Pb2+ during vulnerable periods of development such as synapse formation, gene and protein expression, and other diverse molecular changes associated with these processes.

Infection control practices among correctional healthcare workers: effect of management attitudes and availabiity of protective equipment and engineering controls.

Objectives: To determine the relation of the availability of personal protective equipment (PPE) and engineering controls to infection control (IC) practices in a prison healthcare setting, and to explore the effect on IC practices of a perceived organizational commitment to safety.

Design: Cross-sectional survey.

Setting: The study population was drawn from the 28 regional Correctional Health Care Workers Facilities in Maryland.

Recent events and observations pertaining to smallpox virus destruction in 2002.

To destroy all remaining stocks of variola virus on or before 31 December 2002 seems an even more compelling goal today than it did in 1999, when the 52d World Health Assembly authorized temporary retention of remaining stocks to facilitate the possible development of (1) a more attenuated, less reactogenic smallpox vaccine and (2) an antiviral drug that could be used in treatment of patients with smallpox. We believe the deadline established in 1999 should be adhered to, given the potential outcomes of present research. Although verification that every country will have destroyed its stock of virus is impossible, it is reasonable to assume that the risk of a smallpox virus release would be diminished were the World Health Assembly to call on each country to destroy its stocks of smallpox virus and to state that any person, laboratory, or country found to have virus after date x would be guilty of a crime against humanity.

Caspase-3 and caspase-activated deoxyribonuclease are associated with testicular germ cell apoptosis resulting from reduced intratesticular testosterone.

The purpose of the present study was to examine the possible involvement of caspase-3 and caspase-activated deoxyribonuclease in rat testicular germ cell apoptosis resulting from reduced intratesticular testosterone concentration. Adult Sprague Dawley rats received LH-suppressive testosterone- and estradiol-filled SILASTIC capsules of 2.5 and 0.

Design of a group-randomized Streptococcus pneumoniae vaccine trial.

A group-randomized, double-masked, phase III trial of a Streptococcus pneumoniae conjugate vaccine is being conducted in American Indian populations in the southwestern United States. Approximately 9000 infants will be enrolled in the primary efficacy cohort with vaccine allocation determined by community of residence. The trial is designed to continue until 48 cases of invasive pneumococcal disease due to vaccine serotypes have accumulated.

FDA censoring of manufacturers' postmarketing commitments in HIV/AIDS drug approval letters.

Context: Changing evidentiary standards and partial shift of the investigational phase of drug approval process to the postmarketing phase.

Objective: To determine the availability of information for independent researchers needed to examine accelerated drug approvals to determine how they differ from traditional drug approvals in the HIV/AIDS domain.

Design: Identification of all approved HIV/AIDS and AIDS-related conditions drugs between 1987 and 1999.

Recent weapon carrying and substance use among United States Virgin Islands youth.

The objective of the present study was to estimate the strength of the associations between recent weapon carrying and alcohol, cigarette, and illicit drug use among US Virgin Islands (USVI) youth. Data from 1,124 students in Grades 7-12 were analyzed using the conditional form of multiple logistic regression. Compared with youth who did not carry a weapon.

Early effects of the healthy steps for young children program.

Objective: The Healthy Steps for Young Children Program (HS) incorporates early child development specialists and enhanced developmental services into routine pediatric care. An evaluation of HS is being conducted at 6 randomization and 9 quasi-experimental sites. Services received, satisfaction with services, and parent practices were assessed when infants were aged 2 to 4 months.

Effectiveness of a practice-based intervention to increase vaccination rates and reduce missed opportunities.

Background: Although provider feedback and recall/reminder systems have been shown to increase vaccination rates for children, little is known about the effectiveness of less intensive interventions.

Objective: To determine whether provider prompting at acute care visits in an urban hospital-based outpatient clinic can increase vaccination rates and decrease missed opportunities.

Design And Methods: Study participants, 3 years or younger, were identified from a managed care organization as receiving primary care at the clinic.

Patient notification and follow-up after suspension of treatment protocols. experience from four clinical trials of treatments for AIDS-related CMV retinitis.

We reviewed procedures for and data about patient notification of the suspension of the treatment protocol for four clinical trials. We also examined how data collected after the suspensions were used. All four trials were designed to evaluate treatments for cytomegalovirus retinitis in patients with AIDS and were conducted by the Studies of Ocular Complications of AIDS Research Group.

Clinical review 115: effect of thyroxine therapy on serum lipoproteins in patients with mild thyroid failure: a quantitative review of the literature.

The objective of our study was to estimate the expected change in serum lipoprotein concentrations after treatment with T4 in patients with mild thyroid failure (i.e. subclinical hypothyroidism).

Endogenous estrogens as carcinogens through metabolic activation.

A common thread linking the main risks for developing breast cancer in women is cumulative, excessive exposure to estrogen. The standard paradigm to account for this association focuses on increased cell proliferation caused by estrogen through estrogen receptor-mediated signal transduction accompanied by increased probability for mutation to occur during DNA synthesis. This chapter provides an overview of the mounting evidence, provided from cell culture and whole animal experimental studies, in support of a role for the oxidative metabolites of estrogen, in particular, the catechol estrogens, in the development of estrogen carcinogenesis.

Requirements for double-strand cleavage by chimeric restriction enzymes with zinc finger DNA-recognition domains.

This study concerns chimeric restriction enzymes that are hybrids between a zinc finger DNA-binding domain and the non-specific DNA-cleavage domain from the natural restriction enzyme FOK:I. Because of the flexibility of DNA recognition by zinc fingers, these enzymes are potential tools for cleaving DNA at arbitrarily selected sequences. Efficient double-strand cleavage by the chimeric nucleases requires two binding sites in close proximity.