Impact of interventions for tuberculosis prevention and care in South Africa - a systematic review of mathematical modelling studies

BACKGROUND

Substantial additional efforts are needed to prevent, find and successfully treat tuberculosis (TB) in South Africa (SA). In thepast decade, an increasing body of mathematical modelling research has investigated the population-level impact of TB prevention and careinterventions. To date, this evidence has not been assessed in the SA context.

OBJECTIVE

To systematically review mathematical modelling studies that estimated the impact of interventions towards the World HealthOrganization's End TB Strategy targets for TB incidence, TB deaths and catastrophic costs due to TB in SA.

METHODS

We searched the PubMed, Web of Science and Scopus databases for studies that used transmission-dynamic models of TB in SAand reported on at least one of the End TB Strategy targets at population level. We described study populations, type of interventions andtheir target groups, and estimates of impact and other key findings. For studies of country-level interventions, we estimated average annualpercentage declines (AAPDs) in TB incidence and mortality attributable to the intervention.

RESULTS

We identified 29 studies that met our inclusion criteria, of which 7 modelled TB preventive interventions (vaccination,antiretroviral treatment (ART) for HIV, TB preventive treatment (TPT)), 12 considered interventions along the care cascade for TB(screening/case finding, reducing initial loss to follow-up, diagnostic and treatment interventions), and 10 modelled combinationsof preventive and care-cascade interventions. Only one study focused on reducing catastrophic costs due to TB. The highest impactof a single intervention was estimated in studies of TB vaccination, TPT among people living with HIV, and scale-up of ART. Forpreventive interventions, AAPDs for TB incidence varied between 0.06% and 7.07%, and for care-cascade interventions between 0.05%and 3.27%.

CONCLUSION

We describe a body of mathematical modelling research with a focus on TB prevention and care in SA. We found higherestimates of impact reported in studies of preventive interventions, highlighting the need to invest in TB prevention in SA. However, studyheterogeneity and inconsistent baseline scenarios limit the ability to compare impact estimates between studies. Combinations, rather thansingle interventions, are likely needed to reach the End TB Strategy targets in SA.

Impact of root hairs on microscale soil physical properties in the field

AIMS

Recent laboratory studies revealed that root hairs may alter soil physical behaviour, influencing soil porosity and water retention on the small scale. However, the results are not consistent, and it is not known if structural changes at the small-scale have impacts at larger scales. Therefore, we evaluated the potential effects of root hairs on soil hydro-mechanical properties in the field using rhizosphere-scale physical measurements.

METHODS

Changes in soil water retention properties as well as mechanical and hydraulic characteristics were monitored in both silt loam and sandy loam soils. Measurements were taken from plant establishment to harvesting in field trials, comparing three barley genotypes representing distinct phenotypic categories in relation to root hair length. Soil hardness and elasticity were measured using a 3-mm-diameter spherical indenter, while water sorptivity and repellency were measured using a miniaturized infiltrometer with a 0.4-mm tip radius.

RESULTS

Over the growing season, plants induced changes in the soil water retention properties, with the plant available water increasing by 21%. Both soil hardness (P = 0.031) and elasticity (P = 0.048) decreased significantly in the presence of root hairs in silt loam soil, by 50% and 36%, respectively. Root hairs also led to significantly smaller water repellency (P = 0.007) in sandy loam soil vegetated with the hairy genotype (-49%) compared to the hairless mutant.

CONCLUSIONS

Breeding of cash crops for improved soil conditions could be achieved by selecting root phenotypes that ameliorate soil physical properties and therefore contribute to increased soil health.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11104-022-05530-1.

Significance of root hairs for plant performance under contrasting field conditions and water deficit

BACKGROUND AND AIMS

Previous laboratory studies have suggested selection for root hair traits in future crop breeding to improve resource use efficiency and stress tolerance. However, data on the interplay between root hairs and open-field systems, under contrasting soils and climate conditions, are limited. As such, this study aims to experimentally elucidate some of the impacts that root hairs have on plant performance on a field scale.

METHODS

A field experiment was set up in Scotland for two consecutive years, under contrasting climate conditions and different soil textures (i.e. clay loam vs. sandy loam). Five barley (Hordeum vulgare) genotypes exhibiting variation in root hair length and density were used in the study. Root hair length, density and rhizosheath weight were measured at several growth stages, as well as shoot biomass, plant water status, shoot phosphorus (P) accumulation and grain yield.

KEY RESULTS

Measurements of root hair density, length and its correlation with rhizosheath weight highlighted trait robustness in the field under variable environmental conditions, although significant variations were found between soil textures as the growing season progressed. Root hairs did not confer a notable advantage to barley under optimal conditions, but under soil water deficit root hairs enhanced plant water status and stress tolerance resulting in a less negative leaf water potential and lower leaf abscisic acid concentration, while promoting shoot P accumulation. Furthermore, the presence of root hairs did not decrease yield under optimal conditions, while root hairs enhanced yield stability under drought.

CONCLUSIONS

Selecting for beneficial root hair traits can enhance yield stability without diminishing yield potential, overcoming the breeder's dilemma of trying to simultaneously enhance both productivity and resilience. Therefore, the maintenance or enhancement of root hairs can represent a key trait for breeding the next generation of crops for improved drought tolerance in relation to climate change.

Significance of root hairs at the field scale - modelling root water and phosphorus uptake under different field conditions

ABSTRACT

BACKGROUND AND AIMS

Root hairs play a significant role in phosphorus (P) extraction at the pore scale. However, their importance at the field scale remains poorly understood.

METHODS

This study uses a continuum model to explore the impact of root hairs on the large-scale uptake of P, comparing root hair influence under different agricultural scenarios. High vs low and constant vs decaying P concentrations down the soil profile are considered, along with early vs late precipitation scenarios.

RESULTS

Simulation results suggest root hairs accounted for 50% of total P uptake by plants. Furthermore, a delayed initiation time of precipitation potentially limits the P uptake rate by over 50% depending on the growth period. Despite the large differences in the uptake rate, changes in the soil P concentration in the domain due to root solute uptake remains marginal when considering a single growth season. However, over the duration of 6 years, simulation results showed that noticeable differences arise over time.

CONCLUSION

Root hairs are critical to P capture, with uptake efficiency potentially enhanced by coordinating irrigation with P application during earlier growth stages of crops.

Surface tension, rheology and hydrophobicity of rhizodeposits and seed mucilage influence soil water retention and hysteresis

AIMS

Rhizodeposits collected from hydroponic solutions with roots of maize and barley, and seed mucilage washed from chia, were added to soil to measure their impact on water retention and hysteresis in a sandy loam soil at a range of concentrations. We test the hypothesis that the effect of plant exudates and mucilages on hydraulic properties of soils depends on their physicochemical characteristics and origin.

METHODS

Surface tension and viscosity of the exudate solutions were measured using the Du Noüy ring method and a cone-plate rheometer, respectively. The contact angle of water on exudate treated soil was measured with the sessile drop method. Water retention and hysteresis were measured by equilibrating soil samples, treated with exudates and mucilages at 0.46 and 4.6 mg g-1 concentration, on dialysis tubing filled with polyethylene glycol (PEG) solution of known osmotic potential.

RESULTS

Surface tension decreased and viscosity increased with increasing concentration of the exudates and mucilage in solutions. Change in surface tension and viscosity was greatest for chia seed exudate and least for barley root exudate. Contact angle increased with increasing maize root and chia seed exudate concentration in soil, but not barley root. Chia seed mucilage and maize root rhizodeposits enhanced soil water retention and increased hysteresis index, whereas barley root rhizodeposits decreased soil water retention and the hysteresis effect. The impact of exudates and mucilages on soil water retention almost ceased when approaching wilting point at -1500 kPa matric potential.

CONCLUSIONS

Barley rhizodeposits behaved as surfactants, drying the rhizosphere at smaller suctions. Chia seed mucilage and maize root rhizodeposits behaved as hydrogels that hold more water in the rhizosphere, but with slower rewetting and greater hysteresis.

Plant exudates may stabilize or weaken soil depending on species, origin and time

We hypothesized that plant exudates could either gel or disperse soil depending on their chemical characteristics. Barley (Hordeum vulgare L. cv. Optic) and maize (Zea mays L. cv. Freya) root exudates were collected using an aerated hydroponic method and compared with chia (Salvia hispanica L.) seed exudate, a commonly used root exudate analogue. Sandy loam soil was passed through a 500-μm mesh and treated with each exudate at a concentration of 4.6 mg exudate g-1 dry soil. Two sets of soil samples were prepared. One set of treated soil samples was maintained at 4°C to suppress microbial processes. To characterize the effect of decomposition, the second set of samples was incubated at 16°C for 2 weeks at -30 kPa matric potential. Gas chromatography-mass spectrometry (GC-MS) analysis of the exudates showed that barley had the largest organic acid content and chia the largest content of sugars (polysaccharide-derived or free), and maize was in between barley and chia. Yield stress of amended soil samples was measured by an oscillatory strain sweep test with a cone plate rheometer. When microbial decomposition was suppressed at 4°C, yield stress increased 20-fold for chia seed exudate and twofold for maize root exudate compared with the control, whereas for barley root exudate decreased to half. The yield stress after 2 weeks of incubation compared with soil with suppressed microbial decomposition increased by 85% for barley root exudate, but for chia and maize it decreased by 87 and 54%, respectively. Barley root exudation might therefore disperse soil and this could facilitate nutrient release. The maize root and chia seed exudates gelled soil, which could create a more stable soil structure around roots or seeds.

HIGHLIGHTS

Rheological measurements quantified physical behaviour of plant exudates and effect on soil stabilization.Barley root exudates dispersed soil, which could release nutrients and carbon.Maize root and chia seed exudates had a stabilizing effect on soil.Physical engineering of soil in contact with plant roots depends on the nature and origin of exudates.

Work It Out Together: Preliminary Efficacy of a Parent and Adolescent DVD and Workbook Intervention on Adolescent Sexual and Substance Use Attitudes and Parenting Behaviors

The purpose of the current study was to test an interactive DVD and workbook specifically designed for African-American parents and adolescents (ages 13-18), based on an efficacious face-to-face intervention, to address key factors associated with risk. A total of 170 parent-adolescent dyads were enrolled and randomly assigned to receive either the "Work It Out Together" DVD or a General Health Promotion DVD (HP). Parents and adolescents completed measures of HIV knowledge, self-efficacy, and parenting behaviors. Immediately after receiving the Work It Out Together intervention, parents and adolescents demonstrated higher HIV knowledge and greater HIV prevention self-efficacy. Three months after receiving the Work It Out Together intervention, parents and adolescents reported higher levels of parental monitoring and sexually active adolescents reported higher levels of condom use self-efficacy and a lower rate of recent sex. These outcomes provide preliminary evidence that the "Work It Out Together" DVD impacted individual attitudes and protective parenting behaviors.

Practical management of functional abdominal pain in children

Functional abdominal pain (FAP) is common in childhood, but is not often caused by disease. It is often the impact of the pain rather than the pain itself that results in referral to the clinician. In this review, we will summarise the currently available evidence and discuss the functional dimensions of the presentation, within the framework of commonly expressed parental questions. Using the Rome III criteria, we discuss how to classify the functional symptoms, investigate appropriately, provide reassurance regarding parental worries of chronic disease. We outline how to explain the functional symptoms to parents and an individualised strategy to help restore function.

Epidemiology and control of tuberculosis in Victoria, a low-burden state in south-eastern Australia, 2005-2010

SETTING

Victoria, Australia.

OBJECTIVE

To describe the epidemiology and control of tuberculosis (TB) in Victoria, 2005-2010.

DESIGN

Retrospective review of laboratory-confirmed TB in Victoria, 2005-2010. State TB reference laboratory records were matched with Department of Health notification records to obtain laboratory, demographic, clinical and treatment data.

RESULTS

The incidence of TB fell in the Australian-born population but increased overall, reflecting an increase in the proportion of overseas-born cases from 88.9% to 95.8% between 2005 and 2010 (P = 0.03). Patients from India and Viet Nam accounted for over one third of all cases. For overseas-born cases, the median time between arrival and diagnosis was 4 years. Half of all diagnoses were pulmonary disease, of which 45.4% were Ziehl-Neelsen smear-positive. Treatment was most commonly self-administered (76.9%), and very few patients defaulted or failed treatment (1.1%). Only 4.1% of cases were linked to another laboratory-confirmed case. Multidrug-resistant TB remained uncommon (1.7% of cases).

CONCLUSIONS

TB in Victoria remains low by global standards and continues to overwhelmingly affect the overseas-born population. Current TB control strategies in Victoria are effective, but strengthened control in high-burden countries will also improve TB control locally.

A conceptual model of root hair ideotypes for future agricultural environments: what combination of traits should be targeted to cope with limited P availability?

BACKGROUND

Phosphorus (P) often limits crop production and is frequently applied as fertilizer; however, supplies of quality rock phosphate for fertilizer production are diminishing. Plants have evolved many mechanisms to increase their P acquisition, and an understanding of these traits could result in improved long-term sustainability of agriculture. This Viewpoint focuses on the potential benefits of root hairs to sustainable production.

SCOPE

First the various root-related traits that could be deployed to improve agricultural sustainability are catalogued, and their potential costs and benefits to the plant are discussed. A novel mathematical model describing the effects of length, density and longevity of root hairs on P acquisition is developed, and the relative benefits of these three root-hair traits to plant P nutrition are calculated. Insights from this model are combined with experimental data to assess the relative benefits of a range of root hair ideotypes for sustainability of agriculture.

CONCLUSIONS

A cost-benefit analysis of root traits suggests that root hairs have the greatest potential for P acquisition relative to their cost of production. The novel modelling of root hair development indicates that the greatest gains in P-uptake efficiency are likely to be made through increased length and longevity of root hairs rather than by increasing their density. Synthesizing this information with that from published experiments we formulate six potential ideotypes to improve crop P acquisition. These combine appropriate root hair phenotypes with architectural, anatomical and biochemical traits, such that more root-hair zones are produced in surface soils, where P resources are found, on roots which are metabolically cheap to construct and maintain, and that release more P-mobilizing exudates. These ideotypes could be used to inform breeding programmes to enhance agricultural sustainability.

Long-term follow-up of contacts exposed to multidrug-resistant tuberculosis in Victoria, Australia, 1995-2010

SETTING

The effectiveness of public health strategies following exposure to multidrug-resistant tuberculosis (MDR-TB) is not clear.

OBJECTIVE

To perform long-term follow-up of MDR-TB contacts and review individual outcomes and management approaches.

DESIGN

Retrospective review of MDR-TB contacts identified by the Victorian Department of Health from 1995 to 2010. Health records, including personal medical and pharmacy records and statewide clinical and laboratory TB databases, were searched to identify management strategies and individual outcomes.

RESULTS

A total of 570 contacts of 47 MDR-TB cases were identified, with a total follow-up period of 3093 person-years of observation (PYO) since exposure. Of 570 contacts, 49 (8.6%) were considered likely to have been infected with Mycobacterium tuberculosis from index cases, and 11/49 (22.5%) of these were prescribed preventive therapy tailored to isolate susceptibility. No MDR-TB cases occurred in those receiving preventive treatment, while two cases were observed in those not treated (incidence 2878/100 000 PYO during the first 2 years post exposure).

CONCLUSIONS

The risk of MDR-TB transmission to close contacts in this low-prevalence setting highlights the potential for public health strategies involving preventive treatment.

Pulmonary involvement in type 1 Gaucher disease: functional and exercise findings in patients with and without clinical interstitial lung disease

Pulmonary disease is a well-known complication of Type 1 Gaucher disease (GD), although its incidence is not well established and its severity varies. The purpose of this study was to determine the frequency and extent of pulmonary involvement in patients with GD. Pulmonary involvement was assessed by history, physical examination and chest radiograph in 150 consecutive patients with Type 1 GD presenting at a specialized center for genetic diseases. Five patients were noted to have clinical evidence of pulmonary involvement. Full pulmonary function tests were performed in these five patients and in an additional 13 patients randomly selected from the remaining 145. Many of the 18 patients also underwent radionuclide body imaging with 67 Gallium citrate and 111Indium-tagged leucocyte scans, as well as incremental cardiorespiratory exercise tests. Lung biopsies were available in two patients with lung disease, and a second examination of lung tissue was performed in one of these two patients post-mortem. Clinical lung disease was detected in five patients. All five had dyspnea, diffuse infiltrates, restrictive impairment and low single breath CO diffusing capacity (DLCOSB). Two of these patients underwent exercise testing and showed abnormalities consistent with lung disease (ventilatory limitation, excessive ventilation and increased dead space) as well as decreased VO2 max. and anaerobic threshold (AT). In contrast, in the other 13 patients, physical examination, chest radiographs and pulmonary function were normal (except for a low DLCOSB in one patient). Responses on exercise testing (performed in six of the 13 patients) were consistent with a circulatory impairment (decreased VO2 max. and AT). Our study found that <5% of patients with Type 1 GD have clinical interstitial lung disease. In addition, we found that some patients, without evident lung involvement, may experience limitations in physical exertion and are easily fatigued; this is attributable to impaired circulation.

Promoting safer sex among HIV-positive youth with haemophilia: theory, intervention, and outcome

The goal of the project was to develop and evaluate theory-based interventions designed to change sexual behaviour and promote safer sex practices of HIV seropositive young men and adolescents with haemophilia to prevent transmission to sexual partners and offspring. Safer sex was defined as abstinence, consistent condom use, or 'outercourse' (intimate, non-intercourse sexual behaviour). This project utilized the Transtheoretical Model developed by Prochaska and DiClemente, which describes behaviour change as an incremental, stage-based process. The 1-year intervention protocol consisted of two individual sessions and two peer-centred activities. One hundred and four adolescents, residing in 22 states, participated. Pre- and post-intervention evaluations were conducted to measure stage progression for participants. The number who were in the action or maintenance stage of change for safer sex was significantly greater at post-test than at pre-test (79 vs. 62%, P < 0.0001). Participants also reported an increased use of outercourse. In addition, significant increases in self-efficacy and knowledge regarding safer sex were demonstrated. Following these stage-based interventions, participants were significantly more likely to be engaging in safer sex behaviours than they were previously. These intervention activities can be adapted for use with other adolescent populations and for other behaviour change goals in adolescents with haemophilia.

A prospective study of psychological distress and sexual risk behavior among black adolescent females

OBJECTIVE

The purpose of the study was to examine the association between adolescents' psychological distress and their sexually transmitted disease/human immunodeficiency virus (STD/HIV)-associated sexual behaviors and attitudes.

METHOD

Sexually active black adolescent females (N = 522) completed, at baseline and again 6 months later, a self-administered questionnaire that assessed sexual health attitudes and emotional distress symptoms (using standardized measures, alpha =.84), a structured interview that assessed STD/HIV-associated sexual risk behaviors, and a urine screen for pregnancy.

RESULTS

In multivariate analyses, controlling for observed covariates, adolescents with significant distress at baseline were more likely than their peers, after 6 months, to be pregnant (adjusted odds ratio [AOR]: = 2.0), have had unprotected vaginal sex (AOR = 2.1), have nonmonogamous sex partners (AOR = 1.7), and not use any form of contraception (AOR = 1.5). Additionally, they were also more likely to: perceive barriers to condom use (AOR = 2.2), be fearful of the adverse consequences of negotiating condom use (AOR = 2.0), perceive less control in their relationship (AOR = 2.0), have experienced dating violence (AOR = 2.4), feel less efficacious in negotiating condom use with a new sex partner (AOR = 1.6), and have norms nonsupportive of a healthy sexual relationship (AOR = 1.7).

DISCUSSION

The findings suggest that psychological distress is predictive over a 6-month period of a spectrum of STD/HIV-associated sexual behaviors and high-risk attitudes. Brief screening to detect distress or depressive symptoms among adolescent females can alert the clinician to the need to conduct a sexual health history, initiate STD/HIV-preventive counseling, and refer for comprehensive psychological assessment and appropriate treatment. Among adolescents receiving STD treatment, those with even moderate emotional distress may be at heightened risk for further unhealthy outcomes. STD/HIV interventions should also consider psychological distress as one potential risk factor that may impact program efficacy.

Dopaminergic therapy with carbidopa L-dopa for left neglect after stroke: a case series

OBJECTIVE

To evaluate the efficacy of carbidopa L-dopa (Sinemet) in reducing left spatial neglect after stroke.

DESIGN

Case series.

SETTING

Inpatient neurorehabilitation unit in a regional rehabilitation center.

PARTICIPANTS

A convenience sample of 4 women with right brain strokes and left neglect.

INTERVENTION

A trial of carbidopa L-dopa to treat left neglect, if indicated by selected subtests of the Behavioral Inattention Test (BIT).

MAIN OUTCOME MEASURES

Baseline and posttreatment evaluation with the modified BIT and the FIM instrument.

RESULTS

Three of 4 subjects had significant improvements in their modified BIT scores (8%, 12%, 27%, respectively) and their functional status on the FIM.

CONCLUSION

With further study, carbidopa L-dopa may be shown to reduce unilateral spatial neglect and thereby improve rehabilitation outcomes.

HIV testing among young adults and older adolescents in the setting of acute substance abuse treatment

OBJECTIVES

To examine the feasibility and acceptance of HIV testing among youth in acute substance abuse treatment.

METHODS

Youth, aged 18 to 25 years old, in state-funded inpatient detoxification completed a confidential demographic/risk behavior questionnaire, and were offered a choice of no testing, serum-based testing, or oral fluid (Orasure, Epitope, Inc., Beaverton, OR, U.S.A.) HIV testing.

RESULTS

In all, 74% of 204 participants accepted HIV testing. In a multivariate model, female gender (odds ratio [OR], 0.32; 95% confidence interval [CI] 0.14-0.74) and having been recently tested (OR, 0.11; 95% CI, 0.05-0.26) were independently associated with refusing testing. Recent sexual activity (OR, 5.4; 95% CI, 1.5-20.4), recent use of methamphetamines (speed) or a combination of cocaine and heroin (speedball) (OR, 3.8; 95% CI, 1.6-9.0), and a recent perceived risk for HIV (OR, 4.6; 95% CI, 1.9-10.9) were independently associated with test acceptance. Thus, 150 of 150 (100%) chose the Orasure test. Overall, 64.6% (97 of 150) of those tested received their results, but among participants requiring a follow-up appointment to learn test results, only 9.2% (8 of 87) returned.

CONCLUSIONS

HIV testing is feasible and acceptable in this population. All patients preferred Orasure testing to a serum enzyme-linked immunosorbent assay (ELISA). Most youth tested in detoxification will only learn their results if they are provided during treatment. Rapid HIV testing with same-day results could improve follow-up rates.

Provider issues in HIV care

This chapter examines the impact of HIV infection and its associated biopsychosocial complications on provider-patient relationships and addresses the implications for health care teams and organizations. Several interventions are suggested that can relieve the complex stresses that health care providers are currently experiencing as they care for HIV and AIDS patients.

Comparison of three oral appliances for treatment of severe obstructive sleep apnea syndrome

Objective: To compare three different oral appliances: a mandibular advancement device (Snoreguard), a tongue retaining device, and a soft palate lift, for treatment of severe obstructive sleep apnea syndrome (OSAS).Background: Oral appliances are therapeutic options for patients with OSAS.Methods: Eight patients with a mean apnea hypopnea index (AHI) of 72.1 (SD+/-39.9) were studied. Polysomnographic measures during each of the treatment nights were compared to baseline.Results: Eight out of 8 patients completed the mandibular advancement device (MAD) night; 5/8 tolerated the tongue retaining device (TRD); only 2/8 could sleep with the soft palate lift (SPL) in place. Improvement using the MAD reached significance: overall AHI (mean+/-SD) decreased from 72.1+/-39.9 at baseline to 35.5+/-39.4 with the appliance in place (P<0.02). There was a non-significant increase in slow wave sleep (SWS) from 9.6%+/-8.7 to 14.4%+/-10.5 with the MAD in place. In five responders, the mean AHI decreased from 60.0+/-36.6 to 9.0+/-4.8; all were subjectively improved, using the MAD at 1 year follow-up. However, three non-responders had persistence of AHI>40. With the TRD, AHI decreased from 50.3+/-18.9 at baseline to 43.5+/-32.5 (ns). The SPL was not effective with an AHI at baseline of 52.4+/-8.0, and 47.3+/-31.0 with the device in place (ns), and not well tolerated.Conclusions: A mandibular advancement device is an effective treatment alternative in some patients with severe OSAS. In comparison, the tongue retaining device and the soft palate lift do not achieve satisfactory results.

Impact of sexual abuse on the HIV-risk-related behavior of adolescents in intensive psychiatric treatment

OBJECTIVE

This study compared the HIV-risk-related behaviors and attitudes of adolescents with and without a history of sexual abuse who were in intensive psychiatric treatment.

METHOD

Adolescent patients (N=208) completed measures of psychological functioning and HIV-related knowledge, attitudes, and behaviors.

RESULTS

Among sexually active adolescents in psychiatric treatment (N=116), those with a history of abuse reported significantly less condom self-efficacy (emotional ability to use condoms), less knowledge of HIV, less impulse control, less frequent use and purchase of condoms, and significantly higher rates of sexually transmitted diseases than their peers. Multiple logistic regression indicated that a history of sexual abuse was strongly associated with inconsistent condom use.

CONCLUSIONS

Sexual abuse was associated with HIV-risk-related attitudes and behaviors among adolescents in psychiatric treatment. Clinicians should thus view a history of sexual abuse as a marker for sexual behavior that puts adolescents at risk for HIV.

Transverse myelitis associated with restless legs syndrome and periodic movements of sleep responsive to an oral dopaminergic agent but not to intrathecal baclofen

Periodic limb movement disorder (PLMD) and restless legs syndrome (RLS) are related sleep disorders that occur with increased frequency in spinal cord disease. Effective treatment may be obtained with dopaminergic or opioid drugs, while anticonvulsants, benzodiazepines, and possibly baclofen may be helpful. This report describes a patient who developed RLS and PLMD after acute transverse myelitis associated with infectious mononucleosis, and failed to respond to intrathecal baclofen. All symptoms of RLS/PLMD resolved after treatment with pergolide.

Sexual behavior change among human immunodeficiency virus-infected adolescents with hemophilia. Adolescent Hemophilia Behavioral Intervention Evaluation Project Study Group

PURPOSE

To determine the factors associated with the adoption or maintenance of consistent safer sexual behaviors among human immunodeficiency virus-positive adolescents and young adults with hemophilia.

METHODS

One hundred eleven adolescents at 10 hemophilia care sites participated in an intervention program designed to increase safer sexual behaviors (abstinence, condom use, or nonpenetrative behavior). The theory-based intervention spanned 1 year. Adolescents attended individual sessions, small group activities, and an intensive group retreat.

RESULTS

Patients who maintained or improved safer sexual behaviors were compared with those who relapsed or did not improve. Logistic regression analyses found that improvement and maintenance of safer sexual behavior were significantly associated with perceived peer support for outercourse (odds ratio [OR]: 5.47; confidence interval [CI]: 1.4-20.8), perceived peer support for abstinence (OR: 5.08; CI: 1.2-20.1), and decreased general emotional distress (OR: 4.65; CI: 1.04-20.6). Perceived health status and previous sexual behavior were unrelated to change in safer sexual behavior.

CONCLUSIONS

These longitudinal data indicate that improvement and maintenance of safer sexual behavior among adolescents during an intervention is strongly associated with perceptions of peer support for safer sex and lesser degrees of emotional distress. Programs for human immunodeficiency virus-infected adolescents may require developmentally appropriate social and psychological approaches to impact peer norms and emotional well-being.

Children and adolescents living with HIV and AIDS: a review

Worldwide, more than one million children are infected with human immunodeficiency virus (HIV) and in the United States it has become the sixth leading cause of death among 15-24-year-olds. Despite the trend of increasing rates of infection, advances in therapies have led to survival past 5 years of age for more than 65% of infected children. This global health threat will therefore continue to have a significant impact on child and adolescent psychiatry and psychology. This paper reviews current studies and reports on the consequences of the acquired immunodeficiency syndrome (AIDS) epidemic in the psychiatric care and development of children and adolescents infected by HIV. From a search of all the English-language-based literature on pediatric AIDS, 140 studies are reviewed which address HIV infection and its psychological and social implications. Several topics of mental health significance are examined: (1) the epidemiology of HIV, (2) neurocognitive development among those infected, (3) psychological impact of infection, and (4) the family and social context of HIV. The transition of HIV from an acute, lethal disease to a subacute, chronic disease has enormous implications for the neurocognitive and psychosocial development of children and families. As children and adolescents infected with HIV continue to live longer, normal developmental milestones and educational needs will take on new significance. Many children will continue to be adversely impacted by non-HIV factors such as poverty, inadequate medical services, and a lack of social support. This review outlines recent developments that hold promise to effectively reduce the treatment burden on the infected, their families, and health care providers and to decrease the incidence of transmission to the uninfected.

Reversal of sleep apnea hypopnea syndrome in end-stage renal disease after kidney transplantation

Sleep apnea hypopnea syndrome (SAHS) is extremely common in patients with end-stage renal disease (ESRD). Although the underlying mechanisms linking these 2 conditions remain to be better defined, it is likely that multiple factors are involved. We report an individual with ESRD with severe SAHS that resolved after kidney transplantation. The improvement in SAHS paralleling the effective treatment of ESRD suggests the pathogenesis involves an unstable breathing pattern, possibly caused by an altered metabolic state, uremia, and changes in volume status. The possibility that elevations in cytokine levels could be involved also is discussed and deserves further attention.

Emotional reactions of haemophilia health care providers

This study investigated the prevalence and impact of job burnout and job satisfaction among health care professionals working with HIV-infected patients with haemophilia, using a survey that included the Maslach Burnout Inventory (MBI). A minority (7.4%) of the 213 respondents met the criteria for job burnout as assessed by the MBI. Nearly 90% of the respondents reported 'liking' their job, although only 46% anticipated being in the same job in 5 years. The following factors were associated with increased degrees of burnout: greater perceived colleague stress, less overall job satisfaction, greater perceived stress in the working environment, fewer team meetings and fewer years of career experience. Mental health professionals were also less likely than physicians to report burnout. A multiple logistic regression found that providers who reported stress with colleagues were 42% more likely than their peers to be classified as experiencing a high level of job burnout. This study underscores the importance of a well-functioning team in buffering the inevitable stresses of caring for haemophilia patients with HIV.

HIV-related attitudes and risk behavior of young adolescent mothers

This article reports on the prevalence of HIV-related risk behaviors among young adolescent mothers. To determine the facilitators and barriers to condom use for young adolescent mothers, a survey of HIV-related knowledge, attitudes and behavior and focus groups was conducted. Young mothers (N = 58) have basic knowledge and some personal concern about HIV, but also hold common misconceptions about HIV and people with AIDS. Despite their anxiety about HIV, almost half rarely or never protect themselves against HIV by using a condom. Although 70% of the sample use hormonal contraceptives, more than one third of the sample have had a second child within an average of 18 months after the birth of their first baby. Personal concern about HIV was significantly associated with consistency of condom use. Because of low rates of condom use and substantial rates of multiple sex partners, STDs and second pregnancies, disadvantaged adolescent mothers are at risk of exposure to HIV. Increased personalized concern for HIV may lead to greater motivations for safer behavior for these mothers. In addition to protecting their own safety, the protection of their child may be an important motivator for safe behavior. Cultural taboos against safe sex and the perception of such behavior as "unfeminine" also need to be addressed for these women.

Sleep-related disorders and chronic obstructive pulmonary disease

Sleep-disordered breathing is ubiquitous in COPD. Sleep-related hypoxemia results from hypoventilation attributable to reduced respiratory drive and abnormal mechanics, and from probable changes in V/Q matching. An overlap syndrome combining COPD and OSA also has been described. Disturbances in cardiac, hematologic, and pulmonary function, as well as sleep complaints, are common when COPD is complicated by nocturnal hypoxemia, and these sequelae are even more common when COPD and OSA coexist. Treatment with oxygen is the mainstay for COPD and sleep desaturation alone, whereas combined nasal CPAP and oxygen are most frequently used for the overlap syndrome.

Communicating do-not-resuscitate orders with a computer-based system

BACKGROUND

Do-not-resuscitate (DNR) orders for critically ill patients are frequently miscommunicated between attending physicians, house staff, and nurses. A computer-based system was developed to improve the communication of a procedure-specific DNR order form.

METHODS

Concordance of understanding of patients' DNR status was measured with the use of unstructured DNR orders (period 1), procedure-specific DNR order forms (period 2), and procedure-specific DNR order forms administered with a computer-based communication system (period 3). The 3 components of the DNR order assessed were (1) the clinical events to which the DNR order applied, (2) whether the DNR order withheld all elements of cardiopulmonary resuscitation, and (3) whether other treatments were to be withheld.

RESULTS

For the 147 patients, the computer-based system in period 3 (n = 71) improved concordance for attending physicians and nurses or residents for all 3 of the DNR components compared with period 1 (n = 40) and some of the DNR components compared with period 2 (n = 36). Concordance was "substantial" or "almost perfect" as measured by the K statistic during period 3. The proportion of agreement for the composite of all 3 components of the DNR order increased during each period (P<.001, period 3 vs period 1). Overall agreement between all caregivers for the composite DNR order also improved from period 1 (22.2%) to period 2 (47.8%) and period 3 (61.9%; P<.001 vs period 1). Errors in order entry were detected by physicians because of the computer system and corrected in 9.9% of DNR orders in period 3. Progress note documentation of DNR status did not improve during period 3. The procedures of period 3 were considered acceptable by the physician and nursing staff.

CONCLUSION

A computer-based system combined with a procedure-specific DNR order form improves communication of patients' DNR status in a critical care setting.

Adolescents with psychiatric disorders and the risk of HIV

OBJECTIVE

To review literature relevant to human immunodeficiency virus (HIV)-associated risk behaviors among adolescents with psychiatric disorders and psychological influences on risk behaviors.

METHOD

This report is based on review of 66 articles, which comprise all of the relevant literature in the English language.

RESULTS

Although the seroprevalence of HIV in adolescents with psychiatric disorders is unknown, studies indicate that adolescents with psychiatric disorders are at greater risk than their peers because of increased rates of unsafe sexual practices, impulsivity, self-destructive attitudes, cognitive immaturity, high rates of substance use, self-cutting behavior, and the sequelae of sexual abuse.

CONCLUSION

Directions are proposed for the design of developmentally appropriate, clinically oriented HIV prevention interventions based on the relationships between psychological dysfunction, social stressors, and HIV risk behaviors.

Diagnostic value of tests that discriminate between exudative and transudative pleural effusions. Primary Study Investigators

STUDY OBJECTIVE

To (1) determine appropriate decision thresholds and diagnostic accuracies for pleural fluid (PF) tests that discriminate between exudative and transudative pleural effusions, and (2) evaluate the quality of the primary investigations.

DESIGN

Formal meta-analysis of studies that report the diagnostic value of pleural fluid tests.

SETTING

Data collected from international academic medical centers.

PATIENTS

Hospitalized patients undergoing thoracentesis for pleural effusions.

INTERVENTIONS

Primary investigators were requested to transmit original data from patients described in their studies.

MEASUREMENTS AND RESULTS

Eight primary studies described 1,448 patients with one or more of the following tests: protein (P)-PF, P-PF/serum ratio (R), bilirubin (BILI)-R, lactate dehydrogenase (LDH)-PF, LDH-R, cholesterol (C)-PF, C-R, and albumin gradient. We found that all eight tests had similar diagnostic accuracies when evaluated by receiver operating characteristic (ROC) analysis except for BILI-R, which was less diagnostically accurate. Decision thresholds determined by ROC analysis differed from previously reported values for LDH-PF (>0.45 upper limits of normal) and C-PF (>45 mg/dL). Paired and triplet test combinations tended to have higher diagnostic accuracies compared with individual tests, but examination of the odds ratios with 95% confidence intervals did not identify a clearly superior test combination. Limitations of the primary studies presented a high likelihood of bias affecting their results.

CONCLUSIONS

Several strategies exist for clinicians in utilizing PF tests to classify effusions as exudates or transudates but accurate interpretations of these test results will require better designed studies.

A pilot HIV prevention program for adolescents in a psychiatric hospital

In a pilot HIV prevention program for 35 adolescents in a psychiatric hospital, patients completed assessments of their HIV-related knowledge, attitudes, and behaviors before entering the program, at discharge, and three months after discharge. At discharge they showed significant increases in knowledge, tolerance of people with AIDS, and self-efficacy (or perceived ability to engage in safe-sex behaviors), although those who had been sexually abused showed significantly less change in self-efficacy than others. At three-month follow-up, scores had returned to baseline, but there was a trend toward increased condom use. Findings confirm the need for HIV-AIDS interventions for adolescents in psychiatric settings despite barriers to implementation.

Publications in subspecialty journals on end-of-life ethics

BACKGROUND

Factors that impede patient adoption of advance directives and inhibit physician-patient discussions about end-of-life issues remain incompletely defined. Determination of publication rates of articles on end-of-life ethics in different subspecialty journals may provide insight into physicians' reluctance to promote advance directives for their patients, which appears to vary between subspecialty fields.

OBJECTIVE

To determine publication rates of items on end-of-life issues and other ethics topics.

METHODS

We surveyed core journals from 1976 to 1995 in cardiology (n = 5), critical care medicine (n = 1), nephrology (n = 4), oncology (n = 7), and pulmonary medicine (n = 2).

RESULTS

Critical care medicine (50.4%; 95% confidence interval [CI], 45.0%-55.8%) and pulmonary medicine (27.6%; 95% CI, 22.7%-32.5%) journals published considerably more articles on end-of-life issues than journals in cardiology (4.1%; 95% CI, 0.8%-7.4%), nephrology (11.0%; 95% CI, 7.9%-14.1%), or oncology (6.9%; 95% CI, 1.5%-12.3%). Oncology (30.7%; 95% CI, 25.3%-36.1%), critical care medicine (29.6%; 95% CI, 24.2%-35.0%), and pulmonary medicine (21.5%; 95% CI, 16.6%-26.4%) journals published more items pertaining to all ethics-related topics compared with cardiology (11.0%; 95% CI, 7.3%-14.7%) or nephrology (7.3%; 95% CI, 4.2%-10.4%) journals. Oncology journal ethics articles most often pertained to informed consent or research issues.

CONCLUSIONS

Different internal medicine subspecialty fields demonstrate markedly different patterns of publishing items on topics pertaining to end-of-life issues.

Pulmonary involvement in Fabry disease

Fabry disease is an X-linked inborn error of metabolism resulting from deficient activity of alpha-galactosidase A. Although several case reports have suggested an association between Fabry disease and airway obstruction, this has not been investigated in a large series of patients. We studied 25 unselected, consecutive, enzymatically diagnosed men referred to a General Clinical Research Center for evaluation. Thirty-six percent complained of dyspnea, and 24% had cough and/or wheezing. Symptoms were similar in smokers and nonsmokers. Nine (36%) had airway obstruction on spirometry; this finding was associated with age > or = 26 yr (p < 0.05) and dyspnea or wheezing (p < 0.005), but only weakly with smoking (p = 0.062). Five of eight patients responded to bronchodilators, but all 10 methacholine challenges were negative. Chest radiographs revealed normal lung fields in 24 patients and streaky bibasilar densities in one. No pulmonary uptake occurred on 67Ga citrate scans (18 patients) and 111In-tagged leukocyte scans (16 patients). Specific alpha-galactosidase A mutations were identified in 17 patients; all three patients with frameshift mutations and both subjects with the D264V missense mutation had obstructive impairment. We conclude that airway obstruction commonly occurs in patients with Fabry disease regardless of smoking history, and it increases with age. The presence of obstruction may be associated with certain mutations and most likely results from fixed narrowing of the airways by accumulated glycosphingolipid.

Influence of sexual abuse on HIV-related attitudes and behaviors in adolescent psychiatric inpatients

OBJECTIVE

To investigate the associations between sexual abuse and human immunodeficiency virus (HIV)-related attitudes and behaviors of adolescents with a psychiatric disorder.

METHOD

HIV-related knowledge, attitudes, and behaviors were examined by self-report assessment of adolescents admitted to a psychiatric hospital (N = 100). A subsample (n = 30) completed a role-playing exercise regarding HIV-preventive behavior that was scored for the degree of effective communication by raters blind to the subjects' abuse history.

RESULTS

HIV-related risk behaviors were prevalent, including unprotected sexual intercourse (67%) and multiple partners (27%) among the sexually active (71% of the total). Also frequent were alcohol and drug use (25%) and sharing cutting instruments (22%) among those engaged in self-cutting behavior (62%). The 38% of the sample identified as having a history of sexual abuse indicated significantly poorer self-efficacy concerning condom use than their peers. Abused females scored significantly lower on the self-efficacy of condom use scale and reported significantly more frequent alcohol use than nonabused females (p = .003). A hierarchical multiple regression that controlled for consistency of condom use and tolerance of people with acquired immunodeficiency syndrome found that abuse history uniquely accounted for 16% of the variance in condom use self-efficacy. Analysis of the videotaped role-play found that abused adolescents were significantly less competent and had more difficulty in effective communication than their peers (p = .003).

CONCLUSION

A history of sexual abuse is associated with impaired safe sexual decision-making and HIV-preventive communication skills, even in this already at-risk group. This study also underscores the importance of actively addressing these issues in the context of clinical care.

The accuracy of late antenatal screening cultures in predicting genital group B streptococcal colonization at delivery

OBJECTIVE

To determine the accuracy of late antenatal anogenital cultures in predicting group B streptococcal colonization at delivery.

METHODS

Swabs of the vagina and rectum were obtained from 826 women during routine prenatal visits at approximately 35-36 weeks' estimated gestation. The same women were recultured at admission for delivery. Swabs were cultured in broth media. Test performance indices were calculated using culture status at the time of delivery as the reference. Based on the sensitivity and specificity of antenatal cultures derived from analysis of this study population, we estimated predictive values of late antenatal cultures for a range of group B streptococcal carriage rates.

RESULTS

Group B streptococci were identified in specimens from 219 of 826 women (26.5%). The sensitivity of late antenatal cultures for identifying colonization status at delivery was 87% (95% confidence interval [95% CI] 83-92). Specificity was 96% (95% CI 95-98). Positive predictive value was 87% (95% CI 83-92), and negative predictive value was 96% (95% CI 95-98). Test performance was similar from 1-5 weeks before delivery, but declined when 6 or more weeks had elapsed between the antenatal culture and delivery. Among patients cultured 6 or more weeks before delivery, sensitivity was only 43%, specificity 85%, and positive and negative predictive values were 50 and 81%, respectively. We estimated positive and negative predictive values of 85 and 97% for a colonization rate of 20%, and 79 and 98% for a colonization rate of 15%.

CONCLUSION

Anogenital cultures in broth media obtained during the late antenatal period are accurate in predicting group B streptococcal colonization status at delivery in term parturients, and they perform significantly (P < .01) better than cultures collected 6 or more weeks before delivery.

Doppler sonography in the evaluation of corporovenous competence after penile vein ligation surgery

Doppler ultrasonographic findings in patients after penile vein ligation surgery are described and compared to the results of cavernosometry and cavernosography. Peak systolic and end diastolic velocities were recorded for both cavernosal arteries at 5 min intervals after papaverine injection for a total of 30 min. Peak end diastolic flow rates were compared with cavernosometric and cavernosographic results at 0-10 min, 11-20 min, and 21-30 min. Cavernosography identified venous leakage in nine patients. The end diastolic velocities were greater than the 5 cm/s threshold level generally considered to be indicative of venous leakage in nine of the nine patients (100%) at 0-10 min, in eight of the nine (89%) at 11-20 min, and in nine of the nine (100%) at 21-30 min. Although peak end diastolic velocities at or near the 5 cm/s threshold could be found in patients both with and without recurrent venous leakage in the initial 10 min of the studies, only patients with recurrent venous leakage had diastolic velocities that exceeded the 5 cm/s level when measured 10 min or more after injection. Measurement of end diastolic velocities between 21 and 30 min after injection seemed to discriminate most effectively the patients with recurrent venous leakage from those without leakage in the postoperative population.

Considering individual differences in the design of preventive interventions: HIV primary prevention as an example

This study examined how individual differences in personality style influenced children's receptivity to HIV primary prevention. Prior to taking part in a HIV prevention program, 123 fifth graders from an ethnically diverse inner city school district were administered the Weinberger Adjustment Inventory (WAI) and scales measuring HIV-related beliefs, attitudes, and knowledge. The HIV scales were readministered at the conclusion of the program. WAI groups (formed by contrasting dimensions of restraint and distress) were found to differ significantly on measures of knowledge about HIV, HIV-related fears, safe behavior attitudes, and risk behavior at pre-test. The intervention's impact, as reflected in scale change scores, did not show significant differences among WAI groups. Although subtle differences were evident among groups, findings suggest that HIV primary prevention programs may be equally effective among children with differing degrees of self-restraint and distress.

Prospective validation of an acute respiratory distress syndrome predictive score

We derived an Acute Respiratory Distress Syndrome Score (ARDS Score) from previously described training set data. To validate its diagnostic accuracy for identifying a complicated course (early death or prolonged intubation) in acute lung injury, 50 patients were prospectively scored using an ARDS Score decision threshold of > or = 2.5 to discriminate between an uncomplicated (successful extubation after < or = 14 d) and complicated course. Predictor factors incorporated in the ARDS Score were collected on Day 4 and Day 7 of ARDS and included PaO2/PAO2 ratio, required positive end-expiratory pressure (PEEP), and chest radiograph progression. The diagnostic accuracy of the ARDS Score for determining a complicated course as well as overall survival was compared with three other available indices. Using receiver operating characteristic (ROC) analysis, the ARDS Score and Lung Injury Score (LIS) had the greatest diagnostic accuracy for determining a complicated course, but the Simplified Acute Physiology Score (SAPS Score) (score > or = 14) more accurately identified survival. The LIS components of static respiratory system compliance (Crs) and chest radiograph description did not differ between patient groups. The interobserver concordance of the dynamic chest radiograph interpretation included in the ARDS Score was significant (p < 0.05). We conclude that the previously derived ARDS Score has valid diagnostic accuracy for identifying patients with ARDS who will follow a complicated course.

HIV-infected adolescents with hemophilia: adaptation and coping. The Hemophilia Behavioral Intervention Evaluation Project

OBJECTIVE

It is estimated that 70% of individuals with factor VIII deficiency hemophilia who received blood products before 1985 are infected with human immunodeficiency virus (HIV). The goal of the current study was to assess how adolescents with hemophilia cope with reminders of their HIV status, because adaptation is likely to have implications for these individuals' quality of life and adherence to safer sex recommendations.

METHODS

Participants included 297 HIV-positive adolescents with hemophilia who were recruited from 11 sites across the United States. Adolescents reported on the use and effectiveness of strategies for coping with reminders of their HIV status.

RESULTS

A significant degree of distress was reported in response to such reminders, with anger being the most commonly reported emotion. Although a wide variety of coping strategies had been tried, participants reported using resignation (80.9%), self-calming (78.8%), and distraction (76.4%) most frequently in their attempts to cope with reminders of HIV. Self-blame (3.6%), engaging in risky behaviors (22.2%), thinking about sex (25.4%), and drug/alcohol use (29.1%) were used least. These adolescents tended to rate more active cognitive and behavioral coping strategies (eg, cognitive restructuring, seeking social support, physical activity) as most effective, whereas passive strategies (eg, wishful thinking, blaming others) were reported to be least helpful. Those individuals who reported being distressed by reminders of HIV endorsed most of the coping strategies significantly more often than the nondistressed group, although ineffective strategies were commonly chosen. Sexually active adolescents were more likely than their abstinent peers to cope by thinking about sex, engaging in risky behaviors, or using alcohol and drugs.

CONCLUSION

In this population of adolescents who have known their serostatus for several years, distress about everyday reminders of HIV appears to be associated with ineffective coping strategies.

Pleural fluid chemical analysis in parapneumonic effusions. A meta-analysis

Controversy exists regarding the clinical utility of pleural fluid pH, lactate dehydrogenase (LDH), and glucose for identifying complicated parapneumonic effusions that require drainage. In this report, we performed a meta-analysis of pertinent studies, using receiver operating characteristic (ROC) techniques, to assess the diagnostic accuracy of these tests, to determine appropriate decision thresholds, and to evaluate the quality of the primary studies. Seven primary studies reporting values for pleural fluid pH (n = 251), LDH (n = 114), or glucose (n = 135) in pneumonia patients were identified. We found that pleural fluid pH had the highest diagnostic accuracy for all patients with parapneumonic effusions as measured by the area under the ROC curve (AUC = 0.92) compared with pleural fluid glucose (AUC = 0.84) or LDH (AUC = 0.82). After excluding patients with purulent effusions, pH (AUC = 0.89) retained the highest diagnostic accuracy. Pleural fluid pH decision thresholds varied between 7.21 and 7.29 depending on cost-prevalence considerations. The quality of the primary studies was the major limitation in determining the value of pleural fluid chemical analysis. We conclude that meta-analysis of the available data refines the application of pleural fluid chemical analysis but a clearer understanding of the usefulness of these tests awaits more rigorous primary investigations.

School-based AIDS education for adolescents

PURPOSE

To describe a program which utilizes medical students and persons with AIDS (PWAs) to provide for adolescents school-based education about acquired immunodeficiency syndrome (AIDS).

METHODS

Two 1.5 hour classroom sessions were conducted by medical students and persons with AIDS for seventh and eighth grade students (n = 1,161 students) at two urban middle schools. In addition, a two hour informational session was provided for parents. A 49 question student health survey was used to evaluate adolescents' HIV knowledge, tolerance of persons with AIDS, and intentions to engage in human immunodeficiency virus (HIV) safe behaviors.

RESULTS

Significant (p < 0.01) increases in HIV knowledge and tolerance of persons with AIDS were observed, which persisted for three months. A significant (p < 0.01) improvement in intention to engage in HIV-safe behaviors was observed but did not persist for three months.

CONCLUSIONS

Medical students and persons with AIDS can provide school-based AIDS education to early adolescents.

Cardiorespiratory responses to incremental exercise in sarcoidosis patients with normal spirometry

Patients with sarcoidosis are known to have histologic pulmonary abnormalities despite normal lung fields or conventional pulmonary function or both. These patients permit a useful assessment of the alleged greater sensitivity of the various measurements made during incremental cardiorespiratory exercise testing. Abnormal responses on such testing may provide insight into such complaints as dyspnea in these patients. Incremental exercise testing was performed on 30 patients with biopsy-proven sarcoidosis who had normal spirometry; 13 had clear lung fields radiographically. Of these patients, the 21 who had normal single-breath diffusing capacity for carbon monoxide (Dsb; [group A]) were compared with the 9 who had decreased Dsb (group B). Half of the group A patients had excessive ventilation and 38% had increased dead space to tidal volume ratio (Vd/Vt), but frequencies of these abnormalities were greater in group B, 89 and 78%, respectively. Ventilatory response, as minute ventilation to oxygen consumption ratios ventilatory equivalents, and deadspace to tidal volume ratio (Vd/Vt) ratios were higher in group B. Widened alveolar-arterial oxygen pressure differences were seen in 7 of 9 group B patients but only 1 of 17 group A patients. This study supports the clinical impression that occult pulmonary impairment may be present in patients (in this case, sarcoidosis patients) with normal pulmonary function, and corroborates the utility of exercise testing in demonstrating such impairment. Reduction in Dsb predicted greater frequency of abnormal exercise responses, especially in oxygenation.

Forced midexpiratory time: reference values and the effect of cigarette smoking

BACKGROUND

Forced midexpiratory time (FET25-75%), the time required to exhale from 25 to 75% of forced vital capacity (FVC), has been advocated as a relatively volume-independent measure of obstruction. Previous estimates of normal FET25-75% have not systematically studied the effect of age, height, sex, and smoking history.

METHODS

We analyzed flow-volume loops from 369 normal lifetime nonsmokers and smokers, a random sample of the population of Michigan. Linear models including age and/or height were considered, with and without logarithmic transformation.

RESULTS

The best models used age, or age and height, and no transformation. Age and height contributed much less to the variability of FET25-75% than to spirometric flows previously investigated. The largest r2 was found in the male smokers, with the largest contribution from age, suggesting a smoking effect.

CONCLUSIONS

As age was the major contributor to the value of FET25-75% and that contribution was small, we suggest the use of simplified age-stratified reference values derived from our data.