Selecting haematological malignancy patients for intravenous immunoglobulin.

Prior randomised studies of immunoglobulin replacement therapy have studied mixed populations with or without a history of infections. Immunoglobulin therapy is expensive and in limited supply suggesting that optimising patient selection is of value. In this retrospective study, infection history identified high-risk groups benefiting from treatment. A group of patients without any infection history had a low risk of infection without immunoglobulin.

Future Exploration of the Outer Heliosphere and Very Local Interstellar Medium by Interstellar Probe.

A detailed overview of the knowledge gaps in our understanding of the heliospheric interaction with the largely unexplored Very Local Interstellar Medium (VLISM) are provided along with predictions of with the scientific discoveries that await. The new measurements required to make progress in this expanding frontier of space physics are discussed and include in-situ plasma and pick-up ion measurements throughout the heliosheath, direct sampling of the VLISM properties such as elemental and isotopic composition, densities, flows, and temperatures of neutral gas, dust and plasma, and remote energetic neutral atom (ENA) and Lyman-alpha (LYA) imaging from vantage points that can uniquely discern the heliospheric shape and bring new information on the interaction with interstellar hydrogen. The implementation of a pragmatic Interstellar Probe mission with a nominal design life to reach 375 Astronomical Units (au) with likely operation out to 550 au are reported as a result of a 4-year NASA funded mission study.

Dimethyl sulfoxide-induced reversion of several features of polyoma transformed baby hamster kidney cells (BHK-21). Alterations in growth and morphology.

Cells of a polyoma virus transformed clonal line (Cl-I) of baby hamster kidney fibroblasts (BHK-21) were grown in medium containing 2 percent dimethylsulfoxide (DMSO). Unlike the untransformed BHK-21 cells, Cl-I cells adapted to replication in the presence of DMSO, and they exhibited a rapidly reversible phenotypic reversion of a number of properties characteristic of the transformed state. Restoration of density dependent growth inhibition with accumulation of cells in the G(1) phase of the cell cycle occurred and was associated with restoration of contact dependent behavior and with reversion of histological and ultrastructural features towards those which characterize untransformed cells. Concomitantly, Cl-I cells grown in 2 percent DMSO lost the ability to form colonies in semisolid medium. The data presented suggest that DMSO alters the expression of cellular functions which were altered as a result of viral transformation and which may be involved in cell tumorigenicity.

Retinoic acid inhibits the regulated expression of vascular cell adhesion molecule-1 by cultured dermal microvascular endothelial cells.

The regulated expression of cell adhesion molecules (CAM) on endothelial cells is central to the pathogenesis of various inflammatory processes. Retinoic acid and synthetic derivatives have been demonstrated to exert antiinflammatory effects in cutaneous diseases. To determine modes of retinoid action in the modulation of inflammatory responses, we explored effects of all-trans-retinoic acid (t-RA) on the TNFalpha-induced expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and E-selectin in cultured human dermal microvascular endothelial cells. Pretreatment with t-RA specifically prevented TNFalpha-induced VCAM-1 expression, but not ICAM-1 and E-selectin induction. t-RA significantly reduced VCAM-1-dependent T cell binding to TNFalpha-treated human dermal microvascular endothelial cells as well. This differential modulation of TNFalpha-induced CAM expression by t-RA was reflected at steady state mRNA levels and in nuclear run-on studies. In transcriptional activation studies, the TNFalpha-mediated activation of the human VCAM-1 promoter was inhibited after t-RA treatment, while the ICAM-1 promoter activation was unaffected, indicating that the selective inhibition of CAM expression is regulated in part at the level of gene transcription. Furthermore, the transcriptional inhibition by t-RA appears to be mediated by its effects upon the activation of NF-kappaB-dependent complex formation. Analysis of protein-DNA binding assays revealed marked inhibition of specific NF-kappaB-dependent binding to the tandem NF-KB sites of the VCAM-1 promoter, but not to the functional NF-kappaB motif of the ICAM-1 promoter. The specific inhibition of cytokine-mediated VCAM-1 gene expression in vitro may provide a potential basis by which retinoids exert their biological effects at sites of inflammation in vivo.

Relative risks and population attributable fraction of incident HIV associated with symptoms of sexually transmitted diseases and treatable symptomatic sexually transmitted diseases in Rakai District, Uganda. Rakai Project Team.

OBJECTIVES: To assess the linkage of sexually transmitted disease (STD) symptoms and treatable STD to HIV incidence. DESIGN: Analysis of a randomized trial of STD control for HIV prevention, Rakai, Uganda. METHODS: Consenting adults 15-59 years of age were seen at 10-monthly home visits, interviewed regarding STD symptoms, and asked to provide samples for HIV and STD diagnoses. HIV incidence was determined in 8089 HIV-negative subjects over 10 457 person years. Adjusted rate ratios (RR) and 95% confidence intervals (CI) of HIV acquisition associated with genital ulcer disease (GUD) and discharge/dysuria were used to estimate the population attributable fraction (PAF) of HIV acquisition. HIV transmission risks associated with STD symptoms in HIV-positive partners of 167 HIV discordant couples and the numbers of sexual partners reported by HIV-positive subjects were used to estimate the PAF of HIV transmission attributable to STD. RESULTS: HIV prevalence was 16%. The risk of HIV acquisition was increased with GUD (RR 3.14; CI 1.98-4.98) and in males with discharge/dysuria (RR 2.44; CI 1.17-5.12), but not in females with discharge/dysuria. The PAF of HIV acquisition was 9.5% (CI 2.8-15.8%) with any of the three STD symptoms. The PAF for GUD was 8.8% (CI 3.7-13.8), but only 8.2% of reported GUD was caused by treatable syphilis or chancroid . The PAF for discharge/dysuria in males was 6.7% (CI 1.1-13.8), but only 25% of symptomatic males had concurrent gonorrhea or chlamydial infection. No significant differences were seen in PAF between study treatment arms. The PAF of HIV transmission associated with STD symptoms in HIV-positive persons was indirectly estimated to be 10.4%. CONCLUSION: In this mature, generalized HIV epidemic setting, most HIV seroconversion occurs without recognized STD symptoms or curable STD detected by screening. Therefore, syndromic management or other strategies of STD treatment are unlikely to substantially reduce HIV incidence in this population. However, STD is associated with significant HIV risk at the individual level, and STD management is needed to protect individuals.

A randomized, community trial of intensive sexually transmitted disease control for AIDS prevention, Rakai, Uganda.

OBJECTIVE: To describe the design and first-round survey results of a trial of intensive sexually transmitted disease (STD) control to reduce HIV-1 incidence. STUDY DESIGN: Randomized, controlled, community-based trial in Rakai District, Uganda. METHODS: In this ongoing study, 56 communities were grouped into 10 clusters designed to encompass social/sexual networks; clusters within blocks were randomly assigned to the intervention or control arm. Every 10 months, all consenting resident adults aged 15-59 years are visited in the home for interview and sample collection (serological sample, urine, and, in the case of women, self-administered vaginal swabs). Sera are tested for HIV-1, syphilis, gonorrhea, chlamydia, trichomonas and bacterial vaginosis. Following interview, all consenting adults are offered directly observed, single oral dose treatment (STD treatment in the intervention arm, anthelminthic and iron-folate in the control arm). Treatment is administered irrespective of symptoms or laboratory testing (mass treatment strategy). Both arms receive identical health education, condom and serological counseling services. RESULTS: In the first home visit round, the study enrolled 5834 intervention and 5784 control arm subjects. Compliance with interview, sample collection and treatment was high in both arms (over 90%). Study arm populations were comparable with respect to sociodemographic and behavioral characteristics, and baseline HIV and STD rates. The latter were high: 16.9% of all subjects were HIV-positive, 10.0% had syphilis, and 23.8% of women had trichomonas and 50.9% had bacterial vaginosis. CONCLUSIONS: Testing the effects of STD control on AIDS prevention is feasible in this Ugandan setting.

PIP: An ongoing (1994-98) randomized, community-based trial in Uganda's Rakai District is assessing the assumption that intensive sexually transmitted disease (STD) control efforts result in marked declines in HIV/AIDS prevalence. Described, in this article, are the project design and findings of the first-round baseline survey. 56 communities were grouped into 10 clusters designed to encompass social/sexual networks and clusters within blocks were randomly assigned to the intervention or control arm. All consenting permanent residents of the district are visited in their homes at 10-month intervals where they are administered extensive questionnaires, provide urine and vaginal swab samples, and are offered mass treatment regardless of symptoms or laboratory testing (single oral dose STD treatment in the intervention arm and anthelmintics and iron folate in the control arm). Both groups receive identical health education, condom promotion, and serologic counseling services. In the first round of home visits, 5834 intervention and 5784 control arm subjects were enrolled, representing about 90% of eligible adults. The groups were comparable in terms of sociodemographic and behavioral characteristics and baseline rates of HIV and STDs. 16.9% of subjects were HIV-positive, 10.0% had syphilis, 23.8% of women had trichomonas, and 50.9% had bacterial vaginosis. Detailed STD assessment is expected not only to document the relationship between STD control and HIV, but also to identify which STDs confer the greatest population attributable risk for HIV transmission, facilitating targeted control efforts in the future.

Pervanadate mimics IFNgamma-mediated induction of ICAM-1 expression via activation of STAT proteins.

Differential expression of intercellular adhesion molecule-1 (ICAM-1) in the epidermis plays a critical role in the regulation of cutaneous inflammation, immunologic reactions, and tissue repair. Transcriptional upregulation of ICAM-1 in response to interferon-gamma (IFNgamma) occurs through a palindromic response element pIgammaRE. pIgammaRE is homologous to IFNgamma-activated sequences, which bind to tyrosine phosphorylated members of the transcription factor family known as signal transducers and activators of transcription (STAT). The importance of tyrosine phosphorylation events in the STAT pathway led us to investigate the effect of the protein tyrosine phosphatase inhibitor, pervanadate, on ICAM-1 expression. We show that treatment of A431 cells and human keratinocytes with pervanadate stimulates protein complex formation on pIgammaRE in a time- and concentration-dependent manner. As demonstrated by mobility supershift assays, the pervanadate-stimulated complex is similar to the IFNgamma-stimulated complex and contains Stat1. Pervanadate treatment also led to an increase in overall protein tyrosine phosphorylation and phosphorylation of Stat1, as well as the subsequent increase in ICAM-1 mRNA and cell surface protein levels. These data show that pervanadate can mimic each step in the IFNgamma-mediated pathway leading to ICAM-1 expression, demonstrate the ability of a pharmacologic agent to bypass the standard cytokine-receptor interaction required for increased ICAM-1 expression, and emphasize the importance of protein tyrosine phosphatases and protein tyrosine kinases in mediating inflammatory responses in the skin.

Characterization of electrically evoked [3H]-D-aspartate release from hippocampal slices.

Electrical stimulation has certain advantages over chemical stimulation methods for the study of neurotransmitter release in brain slices. However, measuring detectable quantities of electrically evoked release of endogenous or radiolabeled markers of excitatory amino acid neurotransmitters has required current intensities or frequencies much higher than those usually required to study other transmitter systems. We demonstrate here that [3H]-D-aspartate (D-ASP) release can be detected from hippocampal slices at lower stimulation intensities in the presence of a glutamate reuptake inhibitor. Subsequently, we optimized the electrical stimulus parameters for characterizing electrically evoked D-ASP release. Under the experimental conditions described, greater than 90% of electrically evoked D-ASP release is calcium-dependent. Evoked D-ASP release is markedly reduced by pre-treating slices with the synaptic vesicle toxin bafilomycin A1 (BAF A1) or in the presence of 10-mM magnesium. Evoked D-ASP release is also reduced to variable degrees by N- and P/Q type voltage-sensitive calcium channel antagonists. Neither spontaneous efflux nor evoked D-ASP release were affected by NMDA, AMPA or group I metabotropic glutamate receptor (mGluR) antagonists. Evoked D-ASP release was reduced in the presence of an adenosine A1 receptor agonist and potentiated by treatment with a group I mGluR5 agonist. Evoked [3H]-D-ASP release was similar in magnitude to evoked [3H]-L-glutamate (L-GLU) release. Finally, in separate experiments using the same electrical stimulus parameters, more than 90% of electrically evoked endogenous L-GLU release was calcium dependent, a pattern similar to that observed for evoked [3H]-D-ASP release. Taken together, these results indicate that electrically evoked [3H]-D-ASP release mimics evoked glutamate release in brain slices under the experimental conditions employed in these studies.

Imported malaria in Montagnard refugees settling in North Carolina: implications for prevention and control.

In the winter of 1992, some 402 Southeast Asian refugees were resettled in North Carolina. They received very limited medical screening before immigration and many arrived in the United States with significant health problems, including several tropical infectious diseases. These refugees had lived for many years in remote areas along the Vietnam-Cambodia border, where there is intense transmission of malaria, including Plasmodium falciparum resistant to most antimalarial drugs available in the United States. Of 322 refugees screened after arrival in North Carolina, 187 (58%) were infected: 33% with P. falciparum, 23.5% with P. vivax, 23.5% with P. malariae, and 2.1% with P. ovale. Most infected persons were asymptomatic and infections with multiple species were common. Because of the documented high infection prevalence and the probable presence of many subpatent infections, all nonpregnant refugees were treated with halofantrine; those with P. vivax or P. ovale infections were given primaquine as well. This group accounted for the largest cluster of malaria cases reported in the United States in the last 50 years. Their rapid relocation, with minimal medical screening prior to arrival, resulted in a significant burden to the refugees and to the health-care system. Coordination between immigration agencies, the public health community, and medical workers in communities where the refugees are settled is critical for U.S.-based management of imported tropical diseases.

Safety and pharmacokinetics of intravenously administered trospectomycin sulfate.

Local and systemic tolerance and drug pharmacokinetics were evaluated after a single intravenous infusion of 75 to 1,000 mg of trospectomycin or placebo in 96 healthy volunteers. No clinically significant changes, trends, or abnormalities were observed in the vital signs, electrocardiograms, or laboratory test results; however, there were some statistically significant dose effects or dose-by-time interactions on some of the measures. Mild, transient, local reactions at the infusion site were reported by 20% of the trospectomycin-treated and 22% of the placebo-treated subjects. No irritation of the surrounding tissue was noted when extravasation occurred. Mild, transient, perioral-facial numbness, which was probably drug-related, was the most commonly reported systemic adverse drug experience, occurring in 17 of 64 trospectomycin-treated subjects, but only at doses of 600 mg and above. Pharmacokinetic analyses showed that after a 1,000-mg intravenous dose of trospectomycin, the mean serum half-life was 2.18 hr, the mean area under the curve (AUC) was 157.0 hr x micrograms/ml, the mean maximum concentration (Cmax) was 82.4 micrograms/ml, the mean time to maximum concentration was 25.0 min, and the elimination rate (Ke) was 0.33 hr-1. The Ke and half-life did not vary with dose, and both Cmax and AUC showed a strong linear trend. From 48% to 62% of the dose was excreted in the urine during the first 48 hours after infusion. Under the conditions of this study, intravenous trospectomycin was well tolerated by human subjects at single doses up to and including 1,000 mg.

Prenatal ethanol exposure decreases hippocampal 3H-vinylidene kainic acid binding in 45-day-old rats.

The effect of prenatal ethanol exposure on the kainate-sensitive subtype of glutamate receptor binding sites was studied using in vitro 3H-vinylidene kainic acid (VKA) autoradiography. Pregnant Sprague-Dawley rats were fed a liquid diet containing either 3.35% or 6.7% ethanol throughout gestation. Pair-fed dams received isocalorically matched liquid diets and a lab chow ad lib group served as control for paired feeding. At 45 days of age, the offspring were sacrificed and their brains analyzed for specific 3H-VKA binding. Compared to pair-fed controls, specific 3H-VKA binding was reduced by 13% to 32% in dorsal and ventral hippocampal CA3 stratum lucidum, entorhinal cortex and cerebellum of 45-day-old rats whose mothers consumed either 3.35% or 6.7% ethanol diets. The binding site reductions were statistically significant only in the ventral hippocampal formation and entorhinal cortex of the 3.35% ethanol diet group rats. Saturation of binding studies in the ventral hippocampal formation of 3.35% ethanol rats indicated that the decrease in specific 3H-VKA binding was due to a decrease in the total number of binding sites. Given the excitatory effect of kainic acid on the spontaneous firing rate of hippocampal CA3 pyramidal neurons, the reduction of kainate-sensitive glutamate binding in this region is consistent with the electrophysiological observation of decreased spontaneous activity of CA3 pyramidal neurons in fetal alcohol rats.

Observer variation in bone lesion detection in thoraco-abdominal visceral CT images.

This study measured missed bone diagnosis on CT performed for lymph nodes or visceral spread of cancers and lymphomas. A bone-expert reading was compared to that of visceral-cancer oriented observers. From 100 examinations, 65% of bone abnormalities were not described by current reporting of cancer cases. Changes in windowing and contrast of the image produced large variations in CT readings. A slow search with different windowing decreases the false-negative ratio. A fast reading with invariable viewing parameters increases false interpretations, even for experienced radiologists.

Prenatal ethanol exposure decreases hippocampal 3H-glutamate binding in 45-day-old rats.

The effect of prenatal ethanol exposure on putative glutamate receptor binding sites in rat brain was studied using radiohistochemical techniques. Pregnant Sprague-Dawley rats were fed a liquid diet containing either 3% or 6% (vol./vol.) ethanol throughout gestation. Pair-fed dams received isocalorically matched liquid diets and a lab chow ad lib group served as control for paired feeding. At 45 days of age, the offspring were sacrificed and their brains analyzed by in vitro 3H-glutamate autoradiography. Compared to pair-fed controls, specific 3H-glutamate binding was reduced by 49-53% in regions of the dorsal hippocampal formation of 45-day-old rats whose mothers consumed either 3% or 6% ethanol diets. Specific 3H-glutamate binding was decreased also in the ventral hippocampal formation, entorhinal and posterior neocortex, but to a less consistent degree and magnitude than in dorsal hippocampal formation of fetal alcohol rats. The reduction in hippocampal 3H-glutamate binding 45 days after prenatal ethanol exposure suggests a long-lasting net decrease in glutamate-mediated excitatory neurotransmission within the hippocampal formation of fetal alcohol rats. This glutamate receptor binding site alteration may be one factor contributing to a decrease in long-term potentiation of hippocampal CA1 pyramidal neurons in fetal alcohol rats. In addition, this alteration may underlie learning and other behavioral deficits associated with functional defects of the hippocampal formation.

Prenatal ethanol exposure decreases hippocampal NMDA-sensitive [3H]-glutamate binding site density in 45-day-old rats.

The effect of prenatal ethanol exposure on N-methyl-D-aspartate (NMDA)-sensitive [3H]-glutamate receptor binding site density was studied in rat brain. Pregnant Sprague-Dawley rats were fed a liquid diet containing 3.35% ethanol throughout gestation. This diet produced maternal peak blood ethanol levels of about 39 mg/dl eight hours after the administration of the liquid diet. Pair-fed dams received an isocalorically matched liquid diet and an ad lib lab chow group served as control for the paired feeding technique. At 45 days of age, offspring from each of the three diet groups were sacrificed and brain NMDA-sensitive [3H]-glutamate binding site density measured using in vitro radiohistochemical techniques. NMDA-sensitive [3H]-glutamate binding site density was reduced significantly by 19 to 29% in the apical dendritic field regions of dentate gyrus, hippocampal CA1 and subiculum of dorsal hippocampal formation of fetal alcohol rats compared to pair-fed and ad lib controls. NMDA-sensitive [3H]-glutamate binding site density was not significantly different among the three groups in the ventral hippocampal formation, posterior neocortex, lateral entorhinal cortex or cerebellum. These results are consistent with our previous observations of a reduction in total [3H]-glutamate receptor binding site density in the dorsal hippocampal formation of fetal alcohol rats, as well as more recent electrophysiological observations of a decrease in the sensitivity of fetal alcohol hippocampal slices to NMDA.

Prenatal ethanol exposure during the last third of gestation in rat reduces hippocampal NMDA agonist binding site density in 45-day-old offspring.

The effect of ethanol exposure during different periods of prenatal or postnatal development on hippocampal N-methyl-D-aspartate (NMDA) receptor binding was studied in rat. Fetal rat pups were exposed to ethanol for different periods of time during gestation via maternal consumption of a 3.35% ethanol liquid diet. In a separate experiment, neonatal pups were fed 2.51 g ethanol/kg body weight/day from Postnatal Day (PD) 4 to PD 10 via intragastric feeding tube. These two ethanol administration paradigms produced average peak maternal and pup blood ethanol concentrations of 39 mg/dl and 57 mg/dl, respectively. At 45 days of age, offspring from each treatment group were sacrificed for measurements of hippocampal NMDA-sensitive [3H]-glutamate binding site density using in vitro radiohistochemical techniques. As observed previously, prenatal ethanol exposure throughout gestation resulted in NMDA-sensitive [3H]-glutamate binding site reductions in the apical dendritic field regions of dentate gyrus, hippocampal CA1 and subiculum of dorsal hippocampal formation compared to the ad lib or pair-fed control groups. NMDA-sensitive [3H]-glutamate binding was not different than control in rats exposed to ethanol during the first half of gestation only. Prenatal ethanol exposure during the last half or the last third of gestation resulted in NMDA-sensitive [3H]-glutamate binding site reductions comparable to the binding site reductions observed in rats exposed to ethanol throughout gestation. Hippocampal NMDA-sensitive [3H]-glutamate binding site density in postnatal ethanol-exposed rats was not different than the suckling or gastrostomy control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of a single injection of lincomycin, spectinomycin, and linco-spectin on early chick mortality caused by Escherichia coli and Staphylococcus aureus.

The efficacies of lincomycin (L) and spectinomycin (S), alone and in various combinations (L/S), were determined against Escherichia coli (EC) and Staphylococcus aureus (SA) of avian origin, both in vitro and in vivo. L contributed significantly to L/S activity against SA, while S contributed significantly to L/S activity against EC, and L/S (2.5 mg L + 5.0 mg S) was more effective than either L or S against SA and EC. The suggested optimum dose for controlling early chick mortality caused by SA and EC is 2.5/5.0 mg of L/S per chick.

Intravenous dolasetron mesilate in the prevention of postoperative nausea and vomiting in females undergoing gynecological surgery.

STUDY OBJECTIVE: To evaluate a range of doses of intravenous (i.v.) dolasetron mesilate, in preventing postoperative nausea and vomiting (PONV). DESIGN: Double-blind, placebo-controlled, randomized, multicenter trial. SETTING: Ten hospitals and/or surgical centers. PATIENTS: 281 women undergoing gynecologic surgery with general anesthesia. INTERVENTIONS: Patients received one of four single, i.v. doses of dolasetron mesilate (12.5 mg, 25 mg, 50 mg, and 100 mg) or placebo administered following cessation of anesthesia. MEASUREMENTS AND MAIN RESULTS: Patients were monitored for 24 hours following study drug administration. The antiemetic efficacy of each dolasetron mesilate dose was evaluated by recording the number and timing of emetic episodes, and the effects on nausea were assessed by use of visual analog scales (VAS). Safety was assessed by adverse event reports, clinical laboratory tests, electrocardiographic (ECG) measurements, and monitoring vital signs. Complete responses (patients with no emetic episodes and no escape antiemetic medication requirements in 24 hours) were achieved by 54% in the 12.5-mg, 67% in the 25-mg, and 59% in both the 50-mg and 100-mg dolasetron mesilate dose groups, and by 43% in the placebo group. Nausea VAS assessments demonstrated that dolasetron-treated patients were significantly (p = 0.048) more likely to report no nausea (VAS score < 5 mm) than those in the placebo group. Adverse events reported generally were mild in intensity, and there were no clinically significant changes in laboratory tests, vital signs, or ECG parameters. CONCLUSIONS: Dolasetron was effective and well tolerated for the prevention of PONV in female patients undergoing gynecologic surgery with general anesthesia.

Upper airways obstruction presenting as asthma--three case histories.

Distinguishing an acute asthmatic attack from upper airways obstruction can prove difficult. Three cases of upper airways obstruction presenting as asthma and requiring ventilatory support are reported. Problems relating to correct diagnosis and subsequent management are discussed. Two of the cases were a result of thyroid gland pathology, and the other was due to acute laryngotracheobronchitis.

Community based study of treatment seeking among subjects with symptoms of sexually transmitted disease in rural Uganda.

PIP: This paper presents a community based study of treatment seeking among people with symptoms of sexually transmitted diseases (STDs) in rural Uganda. The effects of asymptomatic infections and treatment seeking behavior on control of sexually transmitted disease were quantified. The study suggests that treating only individuals with STD symptoms results in only a small proportion of the infected population being reached. This situation leads to fewer people receiving effective health care. Thus, STD control programs in medically underserved populations must take into account the prevalence of asymptomatic infections and the health related practices of people with STDs symptoms to design strategies for reducing transmission of these diseases.^ieng