The China tuberculosis clinical trials consortium network: a model for international TB clinical trials capacity building

Background

With the second largest tuberculosis (TB) burden globally, China is committed to actively engage in international TB clinical trials to contribute to global TB research. However, lack of research capacity among local sites has been identified as a barrier.

Main text

The China Tuberculosis Clinical Trials Consortium (CTCTC) was initiated by Beijing Chest Hospital with investment from the US National Institutes of Health and technical support from Family Health International 360 in 2013, as a nationwide collaborative clinical trial network to strengthen selected clinical site research capacity and attract TB clinical trials. The program aims to: 1) recruit leading hospitals that care for TB patients; 2) conduct on-site assessment to identify capacity gaps and needs for improvement; 3) design and deliver capacity building activities; 4) attract and deliver high quality results for TB clinical trials.

A total of 24 sites have joined CTCTC, covering 20 provinces in China. Twenty-two sites have been accredited by the National Medical Products Administration (NMPA) to be qualified to conduct TB clinical trials. The onsite assessment, extensive trainings among the CTCTC sites and young investigators have resulted in better understanding and improvement of the site capacity in conducting TB clinical trials. The establishment and growth of the CTCTC network has benefited from the good leadership, effective international cooperation and local commitment. Issues in human resources, regulatory environment and sustainability have been challenging the network from continuing growth. Clinical researchers have full-time clinical responsibilities in China and it is thus important to build a cadre of other human resources to assist. The regulatory environment is becoming friendlier in China to introduce international clinical trials to the CTCTC network.

Conclusions

The CTCTC, with mature management structure and sustainable development model, which are distilled five key lessons for other developing countries or investigators of interest. They are the respectively using assessment-based approach to design tailored training package, understanding the availability of clinical researchers, providing solutions to maintain sustainability, understanding local regulatory environments and working with an international organization with local on-site team, respectively. Although, the experiences and capacity of China’s TB hospitals in conducting clinical research vary. Considerable efforts to continue building the capacity are still needed, although the gap is smaller for a few top-tier hospitals.

Tackling the unknowns of short-course rifapentine-based treatment for active tuberculosis: a decision analysis

BACKGROUND

Shorter treatment regimens for tuberculosis (TB) are deemed vital for advancing TB control. Murine studies have suggested potential new regimens; however, Phase II human studies of these drug combinations have not shown clear improvement in 2-month culture conversion over current therapy. Nevertheless, drugs such as rifapentine (RPT) may have additional sterilizing effects after 2 months that are difficult to measure in current Phase II studies.

OBJECTIVES

To model potential bactericidal effects of RPT in a Phase III trial of a 4-month anti-tuberculosis regimen.

METHODS

We developed a Markov model of anti-tuberculosis treatment to compare two regimens for treating TB: a 6-month standard (rifampin-based) treatment and a 4-month regimen using high-dose RPT. The primary outcome was the number of relapses.

RESULTS

In the base-case scenario, standard therapy resulted in fewer relapses; improvement in 2-month culture conversion rates in the RPT arm did not change this result. However, while RPT has better sterilizing ability during months 3 and 4 (as observed in the mouse model), the 4-month regimen results in fewer relapses.

CONCLUSIONS

Higher 2-month culture conversion rates are neither sufficient nor necessary for making a theoretical 4-month anti-tuberculosis treatment regimen advantageous.

Factors associated with non-completion of follow-up: 33-month latent tuberculous infection treatment trial

SETTING

A post-hoc exploratory analysis of a randomized, open-label clinical trial that enrolled 8053 participants from the United States, Canada, Brazil, and Spain.

OBJECTIVE

To assess factors associated with non-completion of study follow-up (NCF) in a 33-month latent tuberculous infection treatment trial, PREVENT TB.

DESIGN

Participants were randomized to receive 3 months of weekly directly observed therapy vs. 9 months of daily self-administered therapy. NCF was defined as failing to be followed for at least 993 days (33 months) from enrollment. Possible factors associated with NCF were analyzed using univariate and multivariate regression via Cox proportional hazard model.

RESULTS

Of 7061 adults selected for analysis, 841 (11.9%) did not complete study follow-up. Homelessness, young age, low education, history of incarceration, smoking, missing an early clinic visit, receiving isoniazid only, and male sex were significantly associated with NCF. Similar results were found in the North American region (United States and Canada) only. In Brazil and Spain, the only significant factor was missing an early clinic visit.

CONCLUSIONS

Study subjects at higher risk for NCF were identified by characteristics known at enrollment or in early follow-up. Evaluation of follow-up in other trials might help determine whether the identified factors consistently correlate with retention.

RePORT International: Advancing Tuberculosis Biomarker Research Through Global Collaboration

Progress in tuberculosis clinical research is hampered by a lack of reliable biomarkers that predict progression from latent to active tuberculosis, and subsequent cure, relapse, or failure. Regional Prospective Observational Research in Tuberculosis (RePORT) International represents a consortium of regional cohorts (RePORT India, RePORT Brazil, and RePORT Indonesia) that are linked through the implementation of a Common Protocol for data and specimen collection, and are poised to address this critical research need. Each RePORT network is designed to support local, in-country tuberculosis-specific data and specimen biorepositories, and associated research. Taken together, the expected results include greater global clinical research capacity in high-burden settings, and increased local access to quality data and specimens for members of each network and their domestic and international collaborators. Additional networks are expected to be added, helping to spur tuberculosis treatment and prevention research around the world.

Expanding tuberculosis case notification among marginalized groups in Bangladesh through peer sputum collection

Case notification rates of tuberculosis (TB) in Bangladesh remain poor despite a high burden of disease. Peer sputum collection among underserved populations was implemented to expand case notification and to provide socially empowering roles in society for often excluded members of marginalized populations. Over the 55 months of the evaluation, 32 587 members of key populations were screened for TB, with 1587 smear-positive TB cases detected. Broadening TB services at human immunodeficiency virus drop-in centers using peer sputum collection to target high-risk populations for TB may be an effective way to increase TB case notification among key populations in Bangladesh.

Intermittent tuberculosis treatment for patients with isoniazid intolerance or drug resistance

SETTING

Twenty tuberculosis (TB) clinics in the United States and Canada.

OBJECTIVE

To evaluate the efficacy and safety of a 6-month intermittent regimen of rifampin (RMP), pyrazinamide (PZA) and ethambutol (EMB) in human immunodeficiency virus (HIV) negative patients with culture-confirmed pulmonary or extra-pulmonary tuberculosis and either isoniazid (INH) resistance or INH intolerance.

DESIGN

Patients were enrolled in a single-arm clinical trial to receive intermittent dosing after at least 14 initial daily doses of RMP+PZA+EMB. Treatment was continued twice (BIW) or thrice weekly (TIW) per physician/patient preference for a total of 6 months, with 2 years of follow-up for relapse after treatment.

RESULTS

From 1999 to 2004, 98 patients were enrolled, 78 with reported INH resistance and 20 with INH intolerance. BIW dosing was used in 77 and TIW in 21. Study treatment was completed in 73 (74%). Reasons for discontinuation were hepatic adverse events (n= 12), other adverse effects (n= 3) and other reasons (n= 10). Failure (n= 1) and relapse (n= 2) occurred in 3 (3.5%, 95%CI 1.2-9.8) of 86 patients eligible for efficacy analysis, all occurring in patients with cavitary, acid-fast bacilli smear-positive pulmonary TB.

CONCLUSIONS

Intermittent RMP+PZA+EMB appears to be effective in HIV-negative patients, but the regimen is poorly tolerated, possibly due to the prolonged use of PZA. Alternative regimens of lower toxicity are needed.

Sprint interval exercise elicits near maximal peak VO2 during repeated bouts with a rapid recovery within 2 minutes

AIM

We investigated the cardiorespiratory response during acute sprint interval exercise (SIE; 4 x 30 sec maximal efforts, each separated by 4 min recovery) vs. continuous endurance exercise (CEE; 30 min) at 70% VO2max.

METHODS

Oxygen consumption (VO2) and heart rate were measured in 8 males (age: 23±2.3 y, height: 181±6.4 cm, body mass: 78±8.6 kg, VO2max: 52±3.1 ml·kg-1·min-1, mean±SD). Pre-exercise diet was controlled.

RESULTS AND CONCLUSION

Total VO2 was greater with CEE vs. SIE (87.6±13.1 vs. 35.1±4.4 L O2) with small differences (P=0.06) in average heart rates (CEE: 157±10 bpm vs. SIE: 149±6 bpm) and peak heart rates (CEE: 166±10 vs. SIE: 173±6; P=0.14). VO2 increased during the sprint bouts (53-72% of VO2max) and attained near maximal values (84-96%) in the immediate recovery period (within 20 sec). Thereafter a rapid decrease occurred so that at 2 min of recovery VO2 was ~1.5 L/min (~38% VO2max). During the remaining 2 min of recovery VO2 declined more slowly to ~1.3 L/min or ~33% of VO2max. Similar heart rate responses with CEE and SIE and a greater VO2 during SIE suggest increased muscle oxygen extraction with SIE, which might explain the greater peripheral adaptations, observed previously with sprint vs. continuous training. The potential value of shorter recovery durations to SIE needs to be examined.

A randomized controlled trial of standard versus intensified tuberculosis diagnostics on treatment decisions by physicians in Northern Tanzania

Background

Routine tuberculosis culture remains unavailable in many high-burden areas, including Tanzania. This study sought to determine the impact of providing mycobacterial culture results over standard of care [unconcentrated acid-fast (AFB) smears] on management of persons with suspected tuberculosis.

Methods

Adults and children with suspected tuberculosis were randomized to standard (direct AFB smear only) or intensified (concentrated AFB smear and tuberculosis culture) diagnostics and followed for 8 weeks. The primary endpoint was appropriate treatment (i.e. antituberculosis therapy for those with tuberculosis, no antituberculous therapy for those without tuberculosis).

Results

Seventy participants were randomized to standard (n = 37, 53%) or intensive (n = 33, 47%) diagnostics. At 8 weeks, 100% (n = 22) of participants in follow up randomized to intensive diagnostics were receiving appropriate care, vs. 22 (88%) of 25 participants randomized to standard diagnostics (p = 0.14). Overall, 18 (26%) participants died; antituberculosis therapy was associated with lower mortality (9% who received antiuberculosis treatment died vs. 26% who did not, p = 0.04).

Conclusions

Under field conditions in a high burden setting, the impact of intensified diagnostics was blunted by high early mortality. Enhanced availability of rapid diagnostics must be linked to earlier access to care for outcomes to improve.

Old drugs, new purpose: retooling existing drugs for optimized treatment of resistant tuberculosis

Treatment of drug-resistant tuberculosis is hindered by the high toxicity and poor efficacy of second-line drugs. New compounds must be used together with existing drugs, yet clinical trials to optimize combinations of drugs for drug-resistant tuberculosis are lacking. We conducted an extensive review of existing in vitro, animal, and clinical studies involving World Health Organization-defined group 1, 2, and 4 drugs used in drug-resistant tuberculosis regimens to inform clinical trials and identify critical research questions. Results suggest that optimizing the dosing of pyrazinamide, the injectables, and isoniazid for drug-resistant tuberculosis is a high priority. Additional pharmacokinetic, pharmacodynamic, and toxicodynamic studies are needed for pyrazinamide and ethionamide. Clinical trials of the comparative efficacy and appropriate treatment duration of injectables are recommended. For isoniazid, rapid genotypic tests for Mycobacterium tuberculosis mutations should be nested in clinical trials. Further research focusing on optimization of dose and duration of drugs with activity against drug-resistant tuberculosis is paramount.

MCP1 SNPs and pulmonary tuberculosis in cohorts from West Africa, the USA and Argentina: lack of association or epistasis with IL12B polymorphisms

The monocyte chemotactic protein-1 (MCP-1) is a chemokine that plays an important role in the recruitment of monocytes to M. tuberculosis infection sites, and previous studies have reported that genetic variants in MCP1 are associated with differential susceptibility to pulmonary tuberculosis (PTB). We examined eight MCP1 single nucleotide polymorphisms (SNPs) in a multi-ethnic, case-control design that included: 321 cases and 346 controls from Guinea-Bissau, 258 cases and 271 controls from The Gambia, 295 cases and 179 controls from the U.S. (African-Americans), and an additional set of 237 cases and 144 controls of European ancestry from the U.S. and Argentina. Two locus interactions were also examined for polymorphisms in MCP1 and interleukin 12B (IL12B), another gene implicated in PTB risk. Examination of previously associated MCP1 SNPs rs1024611 (-2581A/G), rs2857656 (-362G/C) and rs4586 (+900C/T) did not show evidence for association. One interaction between rs2857656 and IL12B SNP rs2288831 was observed among Africans but the effect was in the opposite direction in Guineans (OR = 1.90, p = 0.001) and Gambians (OR = 0.64, p = 0.024). Our data indicate that the effect of genetic variation within MCP1 is not clear cut and additional studies will be needed to elucidate its role in TB susceptibility.

Strategies for treating latent multiple-drug resistant tuberculosis: a decision analysis

Background

The optimal treatment for latent multiple-drug resistant tuberculosis infection remains unclear. In anticipation of future clinical trials, we modeled the expected performance of six potential regimens for treatment of latent multiple-drug resistant tuberculosis.

Methods

A computerized Markov model to analyze the total cost of treatment for six different regimens: Pyrazinamide/ethambutol, moxifloxacin monotherapy, moxifloxacin/pyrazinamide, moxifloxacin/ethambutol, moxifloxacin/ethionamide, and moxifloxacin/PA-824. Efficacy estimates were extrapolated from mouse models and examined over a wide range of assumptions.

Results

In the base-case, moxifloxacin monotherapy was the lowest cost strategy, but moxifloxacin/ethambutol was cost-effective at an incremental cost-effectiveness ratio of $21,252 per quality-adjusted life-year. Both pyrazinamide-containing regimens were dominated due to their toxicity. A hypothetical regimen of low toxicity and even modest efficacy was cost-effective compared to “no treatment.”

Conclusion

In our model, moxifloxacin/ethambutol was the preferred treatment strategy under a wide range of assumptions; pyrazinamide-containing regimens fared poorly because of high rates of toxicity. Although more data are needed on efficacy of treatments for latent MDR-TB infection, data on toxicity and treatment discontinuation, which are easier to obtain, could have a substantial impact on public health practice.

Potential economic viability of two proposed rifapentine-based regimens for treatment of latent tuberculosis infection

Rationale

Rifapentine-based regimens for treating latent tuberculosis infection (LTBI) are being considered for future clinical trials, but even if they prove effective, high drug costs may limit their economic viability.

Objectives

To inform clinical trial design by estimating the potential costs and effectiveness of rifapentine-based regimens for treatment of latent tuberculosis infection (LTBI).

Methods

We used a Markov model to estimate cost and societal benefits for three regimens for treating LTBI: Isoniazid/rifapentine daily for one month, isoniazid/rifapentine weekly for three months (self-administered and directly-observed), and isoniazid daily for nine months; a strategy of “no treatment” used for comparison. Costs, quality-adjusted life-years gained, and instances of active tuberculosis averted were calculated for all arms.

Results

Both daily isoniazid/rifapentine for one month and weekly isoniazid/rifapentine for three months were less expensive and more effective than other strategies under a wide variety of clinically plausibly parameter estimates. Daily isoniazid/rifapentine for one month was the least expensive and most effective regimen.

Conclusions

Daily isoniazid/rifapentine for one month and weekly isoniazid/rifapentine for three months should be studied in a large-scale clinical trial for efficacy. Because both regimens performed well even if their efficacy is somewhat reduced, study designers should consider relaxing non-inferiority boundaries.

Perspective: The case for research justice: inclusion of patients with limited English proficiency in clinical research

Persons with limited English proficiency (LEP) constitute a growing portion of the U.S. population, yet they are underrepresented in clinical research. This inherently limits the societal benefits of the research and its generalizability to ethnic populations living in the United States. To illustrate the complexity associated with including LEP participants in clinical research, the authors critically evaluated LEP consent requirements posted on the Web sites of 134 academic health centers in March 2008. They found wide variability with regard to consent policies and striking interinstitutional differences in posted IRB policies and attitudes toward consent of LEP patients in research. The authors argue this variation highlights competing concerns between autonomy and justice. Outcomes-based justice requires inclusion of LEP patients in the research, yet the consent process is often resource-intensive and complex. The authors suggest that more uniform and specific guidance from federal agencies for enrollment of LEP patients in clinical research be established and that this guidance explicitly recalibrate the current balance between autonomy and justice. Investigators and institutional review boards should also develop streamlined best practices to reduce unnecessary effort and expense associated with recruitment of LEP individuals. LEP individuals should have fair access to clinical research in order to fully realize individual and societal benefits of their participation and to ensure the generalizability of scientific discovery.

Interleukin 12B (IL12B) genetic variation and pulmonary tuberculosis: a study of cohorts from The Gambia, Guinea-Bissau, United States and Argentina

We examined whether polymorphisms in interleukin-12B (IL12B) associate with susceptibility to pulmonary tuberculosis (PTB) in two West African populations (from The Gambia and Guinea-Bissau) and in two independent populations from North and South America. Nine polymorphisms (seven SNPs, one insertion/deletion, one microsatellite) were analyzed in 321 PTB cases and 346 controls from Guinea-Bissau and 280 PTB cases and 286 controls from The Gambia. For replication we studied 281 case and 179 control African-American samples and 221 cases and 144 controls of European ancestry from the US and Argentina. First-stage single locus analyses revealed signals of association at IL12B 3′ UTR SNP rs3212227 (unadjusted allelic p = 0.04; additive genotypic p = 0.05, OR = 0.78, 95% CI [0.61–0.99]) in Guinea-Bissau and rs11574790 (unadjusted allelic p = 0.05; additive genotypic p = 0.05, OR = 0.76, 95% CI [0.58–1.00]) in The Gambia. Association of rs3212227 was then replicated in African-Americans (rs3212227 allelic p = 0.002; additive genotypic p = 0.05, OR = 0.78, 95% CI [0.61–1.00]); most importantly, in the African-American cohort, multiple significant signals of association (seven of the nine polymorphisms tested) were detected throughout the gene. These data suggest that genetic variation in IL12B, a highly relevant candidate gene, is a risk factor for PTB in populations of African ancestry, although further studies will be required to confirm this association and identify the precise mechanism underlying it.

NOS2A, TLR4, and IFNGR1 interactions influence pulmonary tuberculosis susceptibility in African-Americans

Tuberculosis (TB) has substantial mortality worldwide with 5-10% of those exposed progressing to active TB disease. Studies in mice and humans indicate that the inducible nitric oxide synthase (iNOS) molecule plays an important role in immune response to TB. A mixed case-control association study of individuals with TB, relatives, or close contact controls was performed in 726 individuals (279 case and 166 control African-Americans; 198 case and 123 control Caucasians). Thirty-nine single nucleotide polymorphisms (SNPs) were selected from the NOS2A gene for single SNP, haplotype, and multilocus interaction analyses with other typed candidate genes using generalized estimating equations. In African-Americans, ten NOS2A SNPs were associated with TB. The strongest associations were observed at rs2274894 (odds ratio (OR) = 1.84, 95% confidence interval (CI) [1.23-2.77], p = 0.003) and rs7215373 (OR = 1.67, 95% CI [1.17-2.37], p = 0.004), both of which passed a false discovery rate correction for multiple comparisons (q* = 0.20). The strongest gene-gene interactions were observed between NOS2A rs2248814 and IFNGR1 rs1327474 (p = 0.0004) and NOS2A rs944722 and IFNGR1 rs1327474 (p = 0.0006). Three other SNPs in NOS2A interacted with TLR4 rs5030729 and five other NOS2A SNPs interacted with IFNGR1 rs1327474. No significant associations were observed in Caucasians. These results suggest that NOS2A variants may contribute to TB susceptibility, particularly in individuals of African descent, and may act synergistically with SNPs in TLR4 and IFNGR1.

HIV-specific health care utilization and mortality among tuberculosis/HIV coinfected persons

Persons coinfected with tuberculosis (TB) and HIV are at high risk of death, in part due to suboptimal utilization of HIV-specific health care. We sought to better understand HIV-associated health care utilization and mortality in a retrospective cohort of TB/HIV coinfected cases reported in North Carolina 1993-2003. In this cohort, HIV was newly diagnosed during TB presentation for 34.2% of coinfected patients. Patients had advanced HIV (median CD4 104 cells/mm(3)) at TB diagnosis. Of 260 patients previously known to be HIV positive, 32.3% had seen a physician for HIV care in the previous 6 months and only 18.5% were taking antiretrovirals when TB was diagnosed; 34.8% of patients started antiretrovirals during TB treatment. Twenty-seven (5%) patients died prior to starting TB treatment; of those who survived, 13.6% (70/515) died prior to completing TB treatment, and 42.7% (220/515) died during a median 1408 days of follow-up. CD4 count (relative risk [RR] 0.53 per 100 cell increase, 95% confidence interval [CI] 0.34, 1.02) and highly active antiretroviral therapy (HAART) use during TB therapy (RR 0.37, 95% CI 0.13, 1.02) were independently associated with decreased mortality, while age greater than 45 (RR 2.18, 95% CI 1.11, 4.29) was independently associated with increased mortality during TB treatment. We conclude that TB/HIV coinfected patients had low utilization rates of HIV-specific care prior to TB diagnosis. Many did not receive potentially lifesaving HIV treatment while on TB therapy, and mortality was high as a result. Interventions to enhance utilization of HIV-related health care and integration of TB and HIV services should be studied to improve outcomes.

Missed opportunities for diagnosis of tuberculosis and human immunodeficiency virus co-infection in Moshi, Tanzania

SETTING

A community-based voluntary counseling and testing (VCT) center in Moshi, Tanzania.

OBJECTIVE

To compare rates of prior human immunodeficiency virus (HIV) testing among clients with and without previous tuberculosis (TB) treatment, and HIV seropositivity among those with and without current TB symptoms.

DESIGN

Cross-sectional study of consecutive clients presenting for initial testing; sociodemographic and clinical data were collected via a structured questionnaire. HIV status was compared among clients with or without three or more TB-related symptoms: weight loss, fever, cough, hemoptysis or night sweats.

RESULTS

Overall, 225 (3%) of 6583 VCT clients who responded to questions on previous TB treatment reported a history of TB, but only 34 (15%) reported previous HIV testing. This rate of HIV testing was not different from the rate among those clients without a history of TB (OR 0.77, P = 0.175). One hundred thirty-five (61%) clients with a history of TB were HIV-infected at VCT, compared with 17% of all clients. Of the total 6592 first-time testers who responded, 372 (6%) had at least three symptoms suggestive of TB at VCT. These symptoms were strongly associated with HIV seropositivity (OR 16.30, P < 0.001).

CONCLUSION

Missed opportunities for HIV diagnosis at the time of TB treatment appear frequent in this population, underscoring the need for integration of TB and HIV diagnostic services.

Variants in toll-like receptors 2 and 9 influence susceptibility to pulmonary tuberculosis in Caucasians, African-Americans, and West Africans

Tuberculosis (TB) is a global public health problem and a source of preventable deaths each year, with 8.8 million new cases of TB and 1.6 million deaths worldwide in 2005. Approximately, 10% of infected individuals develop pulmonary or extrapulmonary TB, suggesting that host defense factors influence development of active disease. Toll-like receptor' (TLR) polymorphisms have been associated with regulation of TLR expression and development of active TB. In the present study, 71 polymorphisms in TLR1, TLR2, TLR4, TLR6, and TLR9 were examined from 474 (295 cases and 179 controls) African-Americans, 381 (237 cases and 144 controls) Caucasians, and from 667 (321 cases and 346 controls) Africans from Guinea-Bissau for association with pulmonary TB using generalized estimating equations and logistic regression. Statistically significant associations were observed across populations at TLR9 and TLR2. The strongest evidence for association came at an insertion (I)/deletion (D) polymorphism (-196 to -174) in TLR2 that associated with TB in both Caucasians (II vs. ID&DD, OR = 0.41 [95% CI 0.24-0.68], p = 0.0007) and Africans (II vs. ID&DD, OR = 0.70 [95% CI 0.51-0.95], p = 0.023). Our findings in three independent population samples indicate that variations in TLR2 and TLR9 might play important roles in determining susceptibility to TB.

Association of SLC11A1 with tuberculosis and interactions with NOS2A and TLR2 in African-Americans and Caucasians

SETTING

Host defense factors may influence the development of active tuberculosis (TB).

OBJECTIVE

To test variants in solute carrier family 11A, member 1 (SLC11A1), for an association with TB.

METHODS

A mixed case-control study of TB cases, relatives or close contact controls, consisting of 474 African-Americans (243 families) and 381 Caucasians (192 families), examined 13 SLC11A1 polymorphisms for association with pulmonary TB using generalized estimating equations adjusting for age and sex.

RESULTS

Two associations were observed in Caucasians (rs3731863, P = 0.03, and rs17221959, P = 0.04) and one in African-Americans (rs3731865, P = 0.05). Multilocus analyses between polymorphisms in SLC11A1 and 11 TB candidate genes detected interactions between SLC11A1 and inducible nitric oxide synthase (NOS2A) in Caucasians (rs3731863 [SLC11A1] x rs8073782 [NOS2A], P = 0.009; rs3731863 [SLC11A1] x rs17722851 [NOS2A], P = 0.007) and toll-like receptor 2 (TLR2) in African-Americans (rs3731865 [SLC11A1] x rs1816702, P = 0.005).

CONCLUSIONS

No association was detected with 5'(GT)(n) promoter polymorphism previously associated with lower SLC11A1 expression, rs17235409 (D543N), or rs17235416 (3' TGTG insertion/deletion polymorphism). SLC11A1 polymorphism rs3731865 was associated with TB in African-Americans, consistent with previous findings in West Africans. These results suggest that variants in SLC11A1 increase susceptibility to pulmonary TB and interact with other variants that differ by race.

Therapeutic drug monitoring of antimycobacterial drugs in patients with both tuberculosis and advanced human immunodeficiency virus infection

STUDY OBJECTIVE

To determine the feasibility of therapeutic drug monitoring for adjusting low serum antimycobacterial concentrations in patients with both tuberculosis and advanced human immunodeficiency virus (HIV).

DESIGN

Retrospective cohort study.

DATA SOURCE

De-identified dataset from a tuberculosis clinic.

PATIENTS

Twenty-one patients (median age 38 yrs, range 25-68 yrs) with advanced HIV infection (CD4(+) cell count < 100 cells/mm(3)) who received treatment for active tuberculosis between March 2002 and September 2007.

MEASUREMENTS AND MAIN RESULTS

We evaluated data based on the practices performed at the tuberculosis clinic. After the daily doses of isoniazid and rifamycins (rifampin or rifabutin) were ingested, serum concentrations were obtained at 2 hours for isoniazid and rifampin, at 3 hours for rifabutin, and, when possible, at 6 hours for all three drugs to detect delayed absorption. Antimycobacterial drug concentrations were compared with published reference levels, and dosages were adjusted to achieve desired concentrations. Costs of monitoring were recorded for all patients. Of the 21 patients, 18 (86%) had low serum concentrations of at least one drug 2 hours after ingestion: 2 (10%) had low isoniazid concentrations, 5 (24%) had low rifamycin concentrations, and 11 (52%) had low serum concentrations of both drugs. The median number of dosage adjustments to attain normal concentrations was 1 (range 0-4 adjustments). The median cost/patient for therapeutic drug monitoring was $619 (range $230-1948). The median final doses to achieve normal concentrations were isoniazid 600 mg/day (range 300-1500 mg/day), rifampin 1050 mg/day (range 600-1200 mg/day), and rifabutin 300 mg (range 150-450 mg) 3 times/week. No patient demonstrated any adverse effects attributed to these higher doses.

CONCLUSION

Low serum concentrations of antituberculous drugs, which suggest malabsorption, are common among patients with advanced HIV who also have tuberculosis but can be overcome with higher doses. Therapeutic drug monitoring may be an effective tool to optimize therapy, but needs further study.

Costs and cost-effectiveness of four treatment regimens for latent tuberculosis infection

RATIONALE

Isoniazid given daily for 9 months is the standard treatment for latent tuberculosis infection (LTBI), but its effectiveness is limited by poor completion rates. Shorter course regimens and regimens using directly observed therapy result in improved adherence but have higher upfront costs.

OBJECTIVES

To evaluate the costs and cost-effectiveness of regimens for the treatment of LTBI.

METHODS

We used a computerized Markov model to estimate total societal costs and benefits associated with four regimens for the treatment of LTBI: self-administered isoniazid daily for 9 months, directly observed isoniazid twice-weekly for 9 months, directly observed isoniazid plus rifapentine once weekly for 3 months, and self-administered rifampin daily for 4 months. In the base-case analysis, subjects were assumed to have newly positive tuberculin skin tests after recent exposure to infectious tuberculosis.

MEASUREMENTS AND MAIN RESULTS

We determined the costs of treatment, quality-adjusted life-years gained, and cases of active tuberculosis prevented. In the base-case analysis, rifampin dominated (less costly with increased benefits) all other regimens except isoniazid plus rifapentine, which was more effective at a cost $48,997 per quality-adjusted life year gained. Isoniazid plus rifapentine dominated all regimens at a relative risk of disease 5.2 times the baseline estimate, or with completion rates less than 34% for isoniazid or 37% for rifampin. Rifampin could be 17% less efficacious than self-administered isoniazid and still be cost-saving compared with this regimen.

CONCLUSIONS

In our model, rifampin is cost-saving compared with the standard therapy of self-administered isoniazid. Isoniazid plus rifapentine is cost-saving for extremely high-risk patients and is cost-effective for lower-risk patients.

Alcohol use and clinical manifestations of tuberculosis

OBJECTIVES

Excess alcohol use represents a significant challenge in tuberculosis control. Whether alcohol use enhances transmission of Mycobacterium tuberculosis is not known.

METHODS

We analyzed North Carolina, USA surveillance data for all adult (> 14 years) tuberculosis cases reported 1994-2006 (N = 5556).

RESULTS

The prevalence of excess alcohol use among tuberculosis cases declined from 27.3% in 1994 to 17.9% in 2006. Cases with excess alcohol use were more likely to have pulmonary tuberculosis compared with cases without excess alcohol use (92.5% vs. 77.2%, p < 0.0001). Among pulmonary cases, excess alcohol use was associated with cavities on chest radiograph (36.8% vs. 28.2%, p < 0.0001) and positive acid-fast sputum smears (65.9% vs. 45.8%, p < 0.0001).

CONCLUSIONS

Although excess alcohol use is becoming less prevalent among tuberculosis cases in North Carolina, cases who use excess alcohol had clinical features associated with greater infectiousness, and represent a significant public health problem.

The value of end-of-treatment chest radiograph in predicting pulmonary tuberculosis relapse

SETTING

Patients with cavitary pulmonary tuberculosis (TB) on baseline chest radiograph (CXR) who remain culture-positive after 8 weeks of treatment are at high risk of relapse. The role of end-of-treatment (EOT) CXR in predicting relapse is unclear.

OBJECTIVE

To determine whether EOT CXR independently predicts TB relapse.

DESIGN

We conducted a secondary analysis of a randomized trial of intermittent treatment using rifapentine in the continuation phase of TB treatment among 1004 human immunodeficiency virus seronegative adults with culture-proven pulmonary TB.

RESULTS

Relapse occurred in 17.3% of subjects with persistent cavity on EOT CXR, in 7.6% of subjects with a cavity that resolved by EOT, and 2.5% (P=0.002 for trend) of subjects who never had a cavity. In multivariable analysis, patients with persistent cavity on EOT CXR were significantly more likely to relapse than patients with no cavity on baseline or 2-month CXR (hazard ratio [HR] 4.22, 95%CI 2.00-8.91), and were more likely to relapse than subjects whose early cavity had resolved by EOT CXR (HR 1.92, 95%CI 1.09-3.39).

CONCLUSION

A persistent cavity after 6 months of TB treatment was independently associated with disease relapse after controlling for other variables. EOT CXR may help predict those likely to relapse.

The virologic, immunologic, and clinical effects of interleukin 2 with potent antiretroviral therapy in patients with moderately advanced human immunodeficiency virus infection: a randomized controlled clinical trial--AIDS Clinical Trials Group 328

BACKGROUND

Interleukin 2 (IL-2) administration increases CD4 counts in persons with higher counts. This study investigated persons with moderately advanced human immunodeficiency virus infection receiving highly active antiretroviral therapy (HAART).

METHODS

Two hundred four patients with CD4 T-cell counts from 50/microL to 350/microL who were treatment naive or had been treated only with reverse transcriptase inhibitors began a specified protease inhibitor HAART regimen. Virologic responders (< or =5000 copies/mL) at 12 weeks were randomized to open-label continuous-infusion IL-2 (IV IL-2), subcutaneous IL-2 (SC IL-2), or HAART alone. Thirty were not randomized and 15 enrolled in a substudy, leaving 159 for analysis. Subjects continued HAART alone for 72 weeks (n = 52) or with IV IL-2 (n = 53) or SC IL-2 (n = 54) for 5 days every 8 weeks. The IV IL-2 subjects could switch to SC IL-2 if their CD4 T-cell count increased by 100/microL or by 25%.

RESULTS

Patients receiving IV or SC IL-2 had greater increases in CD4 cell counts. At week 84, median increases were 459/microL, 312/microL, and 102/microL. Increases of greater than 50% at week 60 (primary end point) were achieved in 39 patients (81%) and 32 (67%) in the IV and SC IL-2 arms, respectively, compared with 13 (29%) in the HAART arm (P<.001 for both). Treatment with IL-2 did not increase plasma human immunodeficiency virus RNA levels. There were fewer new AIDS-defining events in the IV (P = .006) and SC (P = .03) IL-2 groups than in the HAART group (0, 1, and 7, respectively). Drug-related adverse events were more frequent with IL-2 treatment.

CONCLUSION

Addition of IL-2 to HAART can significantly expand CD4 T-cell counts in moderately advanced human immunodeficiency virus infection, without loss of virologic control.

Tuberculosis knowledge and attitudes among physicians who treat young children in North Carolina, USA

SETTING

North Carolina, USA.

OBJECTIVE

To understand physicians' knowledge and attitudes toward the treatment of young children with latent tuberculosis infection (LTBI) in a low-incidence region.

DESIGN

Cross-sectional survey of 525 pediatricians and 525 family practitioners in North Carolina.

RESULTS

Of 1050 surveys mailed, 149 (14%) were returned. In the previous year, 96% of responding physicians had treated children who had emigrated from a tuberculosis (TB) endemic country. During the last 2 years, 84% of physicians had not diagnosed any young children with TB disease, and 46% had not treated any young children with LTBI. Most (83%) physicians routinely placed tuberculin skin tests (TSTs), and 26% reported placing > 10 TSTs per month. Experience in treating children with LTBI was the only predictor of TB knowledge. Physicians were particularly confused about two issues: 1) TST among bacille Calmette-Guérin (BCG) vaccinated children and 2) treatment of young children with recent exposure to an adult with infectious TB.

CONCLUSIONS

Knowledge of important issues related to management of LTBI in children aged < 5 years was limited among physicians in an area with relatively low TB incidence. Creative methods must be developed to help physicians in low-incidence areas to appropriately diagnose and treat LTBI among young children.

Safety of 2 months of rifampin and pyrazinamide for treatment of latent tuberculosis

An alternative regimen for the treatment of latent tuberculosis infection is 2 months of rifampin and pyrazinamide, but some patients have died of hepatitis associated with this therapy. One hundred fourteen patients received rifampin/pyrazinamide in Wake County, North Carolina, between December 1999 and May 2002; 60.5% of these patients were homeless, and at least 17% drank alcohol to excess. Seventy-seven patients (67.5%) completed a full 2-month course. Nine patients had a history of viral hepatitis or chronic liver disease. Four of 114 (3.5%; 95% confidence interval, 1.0-8.7%) patients developed hepatitis on therapy, and another two had symptoms consistent with hepatitis but did not report for laboratory testing (total confirmed plus suspected hepatitis rate 5.3%; 95% confidence interval, 2.0-11.1%). No patient who developed hepatitis had a history of viral hepatitis or liver disease, and none had been previously treated with isoniazid. No patients died or were hospitalized due to drug side effects. Rifampin/pyrazinamide was associated with a significantly higher rate of hepatitis than previously described with isoniazid therapy for latent tuberculosis but resulted in a high completion rate. The rifampin/pyrazinamide regimen for latent tuberculosis infection may be useful for high-risk, traditionally nonadherent patient groups, but careful monitoring for toxicity is required.

A randomized comparative study to determine the effect of omeprazole on the peak serum concentration of itraconazole oral solution

To determine the effect of omeprazole on peak serum concentrations (C(max)) of itraconazole oral solution (IOS), we carried out a randomized, open-label, prospective, crossover study. Fifteen healthy, non-pregnant adults received a single dose of IOS 400 mg on two occasions, at least 7 days apart, with omeprazole 40 mg nightly for 7 days before either IOS dose 1 or 2. C(max), time to C(max) (T(max)) and AUC(0-8) were determined for itraconazole and its active metabolite, hydroxyitraconazole, for each dose and compared. Omeprazole did not significantly affect the C(max), T(max) or AUC(0-8) of itraconazole or hydroxyitraconazole when administered as IOS.

The proactive sexual health history

Family physicians must proactively address the sexual health of their patients. Effective sexual health care should address wellness considerations in addition to infections, contraception, and sexual dysfunction. However, physicians consistently underestimate the prevalence of sexual concerns in their patients. By allocating time to discuss sexual health during office visits, high-risk sexual behaviors that can cause sexually transmitted diseases, unintended pregnancies, and unhealthy sexual decisions may be reduced. Developing a routine way to elicit the patient's sexual history that avoids judgmental attitudes and asks the patient for permission to discuss sexual function will make it easier to gather the necessary information. Successful integration of sexual health care into family practice can decrease morbidity and mortality, and enhance well-being and longevity in the patient.

A prospective, randomized, double-blind study of the tolerability of rifapentine 600, 900, and 1,200 mg plus isoniazid in the continuation phase of tuberculosis treatment

Once-weekly rifapentine 600 mg plus isoniazid (INH) during the continuation phase treatment of tuberculosis is associated with a relapse rate higher than that of twice-weekly rifampin plus INH. The safety and tolerability of higher rifapentine doses need to be determined. We conducted a prospective, randomized, double-blind trial of rifapentine at three doses (600, 900, and 1,200 mg) plus INH 15 mg/kg once weekly in the continuation phase treatment of culture-positive tuberculosis in 150 human immunodeficiency virus-seronegative adults. Outcome measures were discontinuation of therapy for any reason and adverse events on therapy. Treatment was discontinued in 3 of 52 (6%), 2 of 51 (4%), and 3 of 47 (6%) in the rifapentine 600-, 900-, and 1,200-mg treatment arms, respectively. Only one discontinuation, in the rifapentine 1,200-mg arm, was due to an adverse event possibly associated with study therapy. There was a trend toward more adverse events, possibly associated with study therapy, in the highest-dose arms (p = 0.051). Rifapentine 900-mg, once-weekly dosing appears to be safe and well tolerated and is being evaluated in Phase III efficacy trials of treatment of latent tuberculosis. Further evaluation of the safety and tolerability of rifapentine 1,200 mg is warranted.

Hospital management of tuberculosis in a region with a low incidence of tuberculosis and a high prevalence of nontuberculous mycobacteria

We prospectively assessed the management of patients with suspected tuberculosis (TB) in an area with a high prevalence of nontuberculous mycobacteria (NTM) and a low incidence of TB. Clinicians' assessments were sensitive for TB but had poor predictive value. The acid-fast smear was a weak predictor of TB, owing to a high rate of isolation of NTM.

Antiretroviral therapy effects on genetic and morphologic end points in lymphocytes and sperm of men with human immunodeficiency virus infection

Many human immunodeficiency virus (HIV)-infected persons receive prolonged treatment with DNA-reactive antiretroviral drugs. A prospective study was conducted of 26 HIV-infected men who provided samples before treatment and at multiple times after beginning treatment, to investigate effects of antiretrovirals on lymphocyte and sperm chromosomes and semen quality. Several antiretroviral regimens, all including a nucleoside component, were used. Lymphocyte metaphase analysis and sperm fluorescence in situ hybridization were used for cytogenetic studies. Semen analyses included conventional parameters (volume, concentration, viability, motility, and morphology). No significant effects on cytogenetic parameters, semen volume, or sperm concentration were detected. However, there were significant improvements in sperm motility for men with study entry CD4 cell counts >200 cells/mm(3), sperm morphology for men with entry CD4 cell counts < or =200 cells/mm(3), and the percentage of viable sperm in both groups. These findings suggest that nucleoside-containing antiretrovirals administered via recommended protocols do not induce chromosomal changes in lymphocytes or sperm but may produce improvements in semen quality.

Vertical transmission of multidrug-resistant human immunodeficiency virus type 1 (HIV-1) and continued evolution of drug resistance in an HIV-1-infected infant

To confirm the vertical transmission of multidrug-resistant (MDR) human immunodeficiency virus type 1 (HIV-1) and to assess its impact on further evolution of drug-resistant virus in an infant, proviral DNA amplified from infected peripheral blood mononuclear cell cultures was sequenced to identify reverse transcriptase (RT) and protease (PR) mutations. The infant had proviral DNA with evidence of RT mutations (M41L, L74V, and T215Y) and 3 PR substitutions (K20R, M36I, and V82A). After delivery, the mother's proviral DNA had the same substitutions. Phylogenetic analyses of these HIV-1 RT and PR sequences indicated epidemiological linkage. Plasma drug susceptibility was determined by using a recombinant virus assay. Plasma HIV-1 obtained after the infant's birth demonstrated reduced susceptibility to zidovudine and ritonavir. Thus, vertical transmission of MDR HIV-1 was demonstrated in the setting of detectable maternal plasma viremia. Further accumulation of broad MDR in the infant's virus to 3 antiretroviral classes occurred, despite postnatal therapy.

Diabetes reduces right atrial beta-adrenergic signaling but not agonist stimulation of heart rate in swine

This study assessed the effects of streptozotocin diabetes in swine on the heart rate response to beta-adrenergic stimulation the adenylyl cyclase signal transduction pathway. Diabetic animals (n = 9) were hyperglycemic compared to the control group (n = 10) (12.6 +/- 1.0 vs. 3.53 +/- 0.29 mM). There were no significant differences between the diabetic and nondiabetic groups in the heart rate response to isoproterenol, however, there was a significant reduction (14%) in beta-adrenergic receptor density in the right atrium in the diabetic (61 +/- 3 fmol/mg protein) versus the nondiabetic group (71 +/- 3) (P < 0.05). The content of guanosine triphosphate binding regulatory proteins (Gs and Gi) in the right atrium was not affected by diabetes, nor was adenylyl cyclase activity under unstimulated conditions or with receptor-dependent stimulation with isoproterenol. On the other hand, adenylyl cyclase activity was 34% lower when directly stimulated with forskolin, and it was reduced by 23% when stimulated through Gs with Gpp(NH)p. In conclusion, beta-adrenergic stimulation of heart rate with isoproteronol and the receptor-dependent signal transduction pathway remained intact in the right atrium of diabetic swine despite reduced beta-adrenergic receptor density, G-protein content, and direct stimulation of adenylyl cyclase activity.

Antepartum or postpartum isoniazid treatment of latent tuberculosis infection

OBJECTIVE

To compare health outcomes and costs of different strategies for treatment of latent tuberculosis infection in pregnancy.

METHODS

Using a Markov decision-analysis model, the following three strategies were evaluated for treatment of latent tuberculosis infection in pregnancy, defined as positive tuberculin skin reaction of 10 mm or greater and negative chest radiograph: no treatment, antepartum isoniazid administration, in which women were given 300 mg of isoniazid with pyridoxine beginning at 20 weeks' gestation for 6 months; and postpartum isoniazid, in which women were given isoniazid and pyridoxine for 6 months after delivery. Sensitivity analyses were performed for a wide range of probability and cost estimates, and considered discount rates.

RESULTS

Under base-case assumptions, the fewest cases of tuberculosis within the cohort occurred with antepartum treatment (1400 per 100,000) compared with no treatment (3300 per 100,000) or postpartum treatment (1800 per 100,000). Antepartum treatment resulted in a marginal increase in life expectancy due to the prevented cases of tuberculosis, despite more cases of isoniazid-related hepatitis and deaths, compared with no treatment or postpartum treatment. Antepartum treatment was the least expensive. Only if the case-fatality rate for tuberculosis was tenfold lower than the base-case and the risk of fatal hepatitis tenfold higher did antepartum treatment become the least advantageous strategy.

CONCLUSION

Rather than delaying treatment until postpartum, consideration for antepartum treatment of latent tuberculosis during pregnancy should be given. If isoniazid is not administered antepartum, then efforts to improve postpartum compliance should be instituted, as either antepartum or postpartum treatment is better than no treatment.

Excessive use of vancomycin: a successful intervention strategy at an academic medical center

The project goal was to decrease excessive vancomycin use. Interventions included an educational chart note the first day of therapy, followed by pharmacists discussing the need for continued therapy with patients' physicians. Empirical vancomycin use improved from 20% to 90% compliance with guidelines within 6 months of the intervention.

The use of a transscrotal testosterone delivery system in the treatment of patients with weight loss related to human immunodeficiency virus infection

PURPOSE

Weight loss is a strong predictor of morbidity and mortality in human immunodeficiency virus (HIV)-infected patients. Men with acquired immunodeficiency syndrome (AIDS) lose body cell mass. Hypogonadism is also common. This study tested the efficacy of a testosterone transscrotal patch (6 mg/day) in improving body cell mass and treating hypogonadism in these patients.

SUBJECTS AND METHODS

This multicenter, randomized, double-blinded, placebo-controlled trial was conducted from August 1995 to October 1996 in 133 men, 18 years of age and older, who had AIDS, 5% to 20% weight loss, and either a low morning serum total testosterone level (<400 ng/dL) or a low free testosterone level (<16 pg/mL). Outcomes included weight, body cell mass as measured using bioelectrical impedance analysis, quality of life, and morning measurements of serum testosterone and dihydrotestosterone levels, lymphocyte subsets, and HIV quantification.

RESULTS

There were no significant differences in baseline weight, CD4 cell counts, or HIV serum viral quantification between treatment arms. Morning total and free testosterone levels increased in those treated with testosterone, but not with placebo. Following 12 weeks of treatment there were no differences (testosterone-placebo) in mean weight change (-0.3 kg [95% confidence interval (CI): -1.4 to 0.8]) or body cell mass (-0.2 kg [95% CI: -1.0 to 0.6]) in the two groups. There were also no changes in quality of life in either group.

CONCLUSION

Hypogonadal men with AIDS and weight loss can achieve adequate morning serum sex hormone levels using a transscrotal testosterone patch. However, this system of replacement does not improve weight, body cell mass, or quality of life.

Recent Developments in Epidemiology, Treatment, and Diagnosis of Tuberculosis

The resurgence in cases of active tuberculosis in North America in the past decade has prompted increases in funding for tuberculosis treatment, research, and education. As a result, the number of new cases of tuberculosis has declined and cases occur in smaller pockets of well-characterized populations, such as communities of foreign-born persons and socioeconomically disadvantaged groups. New strategies for the treatment of both active and latent tuberculosis may soon include the newly licensed, long-acting rifamycin, rifapentine, but further studies are needed to determine optimal dosing regimens for this agent. Experts in tuberculosis and HIV infection have made headway in defining the optimal therapy for each current therapeutic option, and recently published guidelines are a useful document for clinicians. Rifabutin-based regimens are one approach toward achieving the optimal treatment of both diseases simultaneously. Finally, newly licensed molecular diagnostic tests for direct use on clinical specimens are intriguing, but their clinical utility remains to be defined.

Clostridium septicum myonecrosis presenting as a parapharyngeal abscess in a patient with aplastic anemia

The first reported case of Clostridium septicum myonecrosis in an adult with aplastic anemia is described. The patient presented with sepsis, a parapharyngeal abscess that necessitated emergent intubation, and severe intravascular hemolysis attributed to clostridial alpha-toxin production. Despite prompt recognition and treatment, the patient died of his infection. C. septicum myonecrosis should be considered in any immunocompromised patient with sepsis, especially when accompanied by evidence of multiple sites of tissue infection.

The reharvested central third of the patellar tendon. A histologic and biomechanical analysis

We assessed the histologic, mechanical, and structural properties of the reharvested central-third patellar tendon in greyhounds. Twelve dogs had the central third of the patellar tendon (5 mm) removed with corresponding bone blocks from the patella and tibia; the remaining tendon defect was loosely closed. Six dogs were sacrificed at 6 months and six at 12 months, and the central third of the patellar tendon was harvested from both the operative and the contralateral control knees. Analysis of the structural changes in the tendons revealed a significant increase in thickness for reharvested tendons at both 6 and 12 months when compared with controls. The entire residual tendons were narrower at 6 months and were shorter at 12 months compared with controls. Mechanical testing showed that the average failure load, ultimate tensile strength, strain at failure, and average modulus for the reharvested central third of the patellar tendon were significantly less than that of controls at both 6 and 12 months. Analysis of collagen fiber size by electron microscopy revealed a significant increase in collagen fiber diameter at 6 months (135 +/- 41 nm versus 49 +/- 4 nm) but no difference between the operative limbs and controls at 12 months. The reharvested bone-patellar tendon-bone complex does not have the same properties as the primary patellar tendon graft up to 1 year after harvest in a canine model, and its use for revision cruciate ligament reconstruction must be carefully reexamined.

The fibular collateral ligament-biceps femoris bursa. An anatomic study

The anatomy of the fibular collateral ligament-biceps femoris bursa is described. The bursa is located lateral to the distal quarter of the fibular collateral ligament and forms an inverted "J" shape around the anterior and anteromedial portions of the ligament. Its most distal margin is just proximal to the fibular head where the fibular collateral ligament inserts, and its more proximal aspect is at the superior edge of the anterior arm of the long head of the biceps femoris muscle. We found this structure in all 50 knees dissected; there was a constant anatomic location of the fibular collateral ligament-biceps femoris bursa in all specimens. Measurement of the anatomic dimensions of the bursa revealed a mean width of 8.4 mm and a mean height of 18 mm. Knowing the prevalence, shape, size, and anatomic location of this bursa may aid the clinician in the differential diagnosis of lateral knee pain.

A patient's guide to safer sex. Reducing the risk of HIV and other sexually transmitted diseases

In summary, each person must be responsible for his or her own sexual health and, unfortunately, there are some deadly infections in the population these days. We hope this frank discussion of options will help you make smart decisions about your sex life.

Impaired pyruvate oxidation but normal glucose uptake in diabetic pig heart during dobutamine-induced work

We tested the hypothesis that diabetes impairs myocardial glucose uptake and pyruvate oxidation under normal conditions and during a dobutamine-induced increase in work. We also tested the hypothesis that an increase in work would result in a decrease in the levels of malonyl CoA, a potent inhibitor of carnitine palmitoyltransferase I (CPT I). Streptozotocin-diabetic micropigs were compared with a nondiabetic control group (n = 8 per group). Triglyceride emulsion, glucose, and somatostatin were infused into the nondiabetic group to create an acute diabetic-like state. In accord with our hypothesis, malonyl CoA decreased significantly with dobutamine in both groups, providing a possible mechanism for increased fatty acid oxidation through relieved inhibition on CPT I. In the absence of dobutamine, glucose uptake and tracer-measured lactate uptake were decreased by 57 and 80%, respectively, in the diabetic group. Dobutamine infusion resulted in similar increases in cardiac contractility, oxygen consumption, and glucose uptake in both groups despite reductions of 50-65% in GLUT-4 and GLUT-1 protein in the diabetic group. Diabetic animals possessed a defect in myocardial pyruvate oxidation, as reflected in increased lactate production, and depressed lactate uptake and pyruvate dehydrogenase activity under control and dobutamine conditions. In conclusion, the major derangement in carbohydrate metabolism in diabetic myocardium was not in glycolysis but, rather, in pyruvate oxidation.

Dynamic stability of the elbow: electromyographic analysis of the flexor pronator group and the extensor group in pitchers with valgus instability

The medical collateral ligament is a common site of injury in baseball pitchers, causing substantial morbidity and loss of pitching time. Twenty-six skilled baseball pitchers with medial collateral ligament insufficiency were studied before surgery with high-speed cinematography and fine-wire electromyography of eight muscles around the elbow. Data from the pitchers with injured elbows were compared with data obtained from uninjured pitchers. The flexor carpi radialis muscle in the pitchers with medial collateral ligament deficiencies revealed significantly decreased firing during the acceleration and deceleration phase of the fastball when compared with that of the pitchers with normal elbows, and the flexor carpi radialis muscle was significantly depressed during the early cocking and deceleration phases. The extensor muscles revealed slightly increased activity in the injured elbows; however, this was not statistically significant. Although the muscles of the flexor pronator group (especially the flexor carpi ulnaris muscle and the flexor digitorum superficialis muscles) are anatomically positioned to provide dynamic stability of the elbow, they did not demonstrate increased electrical activity in pitchers with medial collateral ligament deficiencies. This finding suggests that the muscles on the medial side of the elbow do not supplant the role of the medial collateral ligament during the fastball pitch.

Adrenergic desensitization in left ventricle from streptozotocin diabetic swine

Patients with diabetes mellitus that exhibit cardiac pump failure display compromised stroke volume, ejection fraction, and slower rates of rise and fall of left ventricular (LV) dP/dt in the absence of ischemic injury. We hypothesized that diabetic cardiomyopathy may involve decrements in adrenergic sensitivity, with specific molecular alterations in the beta-adrenergic receptor (beta AR)- G protein- adenylyl cyclase (AC) signal transduction system. We assessed the effects of 3 months of streptozotocin-induced diabetes (125 mg/kg i.v.; DIAB, n = 10) on myocardial signal transduction in mini-pigs. DIAB were hyperglycemic compared to controls (CON, n = 10; 20.92 +/- 2.64 v 5.24 +/- 0.35 mM glucose), and had lower fasting insulin levels (6.46 +/- 0.97 v 13.68 +/- 3.91 microU/ml). Transmural LV free wall homogenates from DIAB exhibited similar beta AR density as CON, but decreased cAMP production (pmol cAMP/mg prot.min) using these pharmacological stimulators: 10 microM Isoproterenol plus 100 microM GTP (74 +/- 5 v 97 +/- 11); 100 microM Gpp(NH)p (116 +/- 7 v 161 +/- 17); 10 mM fluoride ion (266 +/- 16 v 324 +/- 25). No differences between DIAB and CON were observed when stimulated by 100 microM forskolin (440 +/- 20 v 429 +/- 33), suggesting no alterations in the catalytic subunit of AC. In DIAB, quantitative immunoblotting indicated slightly depressed levels of Gs (552 +/- 44 v 630 +/- 59 pmol/g ww; NS), but a significant redistribution of alpha s from the sarcolemma to the cytosol (32.7 +/- 0.82% v 25.9 +/- 1.7%). Significantly elevated levels of cardiac Gi were seen in DIAB homogenates compared to CON ventricles (2326 +/- 145 v 1522 +/- 181 pmol/g ww), with no alpha i subunit redistribution. We conclude that despite maintained beta AR density, receptor-dependent and G protein-dependent stimulation of AC is depressed so that streptozotocin-induced diabetic LV is affected by increased cardiac Gi, redistribution of Gs alpha to the cytosol, and an increase in the Gi/Gs ratio. These results help explain depressed catecholamine responsiveness and cardiac performance exhibited by diabetic patients.

Myocardial interstitial purine metabolites and lactate with increased work in swine

OBJECTIVE

Dobutamine stimulates the beta-receptors in the heart and increases myocardial blood flow and oxygen consumption 2-3-fold, similar to effects seen with exercise. The purpose of this study was to assess temporal changes in myocardial interstitial purine metabolites, adenosine monophosphate (AMP) and lactate during and following 30 min of dobutamine infusion.

METHODS

Dobutamine (15 micrograms/kg/min) was infused via the jugular vein into 9 anesthetized, open-chest, domestic swine. Interstitial fluid was sampled with microdialysis probes placed in the midmyocardium. The effluent from the probes, referred to as the dialysate, was used to estimate myocardial interstitial purine metabolites, AMP, and lactate levels before, during, and following a dobutamine-induced increased work state.

RESULTS

Dobutamine infusion resulted in a 77% increase in heart rate, a 258% increase in left ventricular dP/dt, a 208% increase in myocardial oxygen consumption, and a 155% increase in rate x pressure product. Myocardial blood flow was increased in the subepicardium, midmyocardium, and subendocardium by 207, 268, and 268%, respectively, compared to the control period. Neither coronary venous nor dialysate lactate concentrations changed throughout the protocol. Dialysate adenosine and AMP levels were both significantly elevated (P < 0.05) during the dobutamine period and fell back to control values during the recovery period.

CONCLUSIONS

The dobutamine-induced increases in myocardial oxygen consumption, rate x pressure product, and blood flow, without an increase in coronary venous or interstitial lactate suggest that energy balance is maintained during dobutamine infusion. Thus an increase in myocardial work, in the absence of demand-induced ischemia, resulted in accumulation of adenosine and AMP in the interstitium.