Robust Reconstitution of Tuberculosis-Specific Polyfunctional CD4+ T-Cell Responses and Rising Systemic Interleukin 6 in Paradoxical Tuberculosis-Associated Immune Reconstitution Inflammatory Syndrome

BACKGROUND

The immunopathogenesis of paradoxical tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) remains unclear. We determined the association between pathogen-specific T-cell responses and development of paradoxical TB-IRIS on antiretroviral therapy (ART).

METHODS

This study was nested within a prospective cohort study of HIV-infected patients with active pulmonary tuberculosis and baseline CD4 counts ≤125 cells/µL initiating ART. T-cell immune activation (CD38, HLA-DR, and PD-1 expression), phenotype, and polyfunctional pathogen-specific cellular immune responses prior to and 4 weeks after ART initiation were determined by flow cytometry. Patients with TB-IRIS were compared to non-IRIS controls using χ(2) and rank-sum tests and logistic regression.

RESULTS

TB-IRIS patients and controls had similar CD4 counts, levels of T-cell-associated immune activation, frequencies of T-cell memory subsets, and frequencies of interferon gamma (IFN-γ(+))/interleukin 2 (IL-2(+))/tumor necrosis factor alpha (TNF-α(+)) CD4(+) T-cells prior to ART initiation. After ART initiation, cellular immune activation and T-cell subsets also were similar in TB-IRIS patients and controls. In contrast, TB-IRIS patients had significantly greater early increases in the frequency of tuberculosis-specific polyfunctional IFN-γ(+)/IL-2(+)/TNF-α(+) CD4(+) T-cells on ART (P = .02); each quartile increase in the percentage of these cells was independently associated with a 2.8-fold increased risk of TB-IRIS (95% confidence interval, 1.1 to 7.5-fold). In a secondary analysis, patients with TB-IRIS had rapid, concomitant increases in tuberculosis-specific adaptive immune responses and interleukin 6 (IL-6) levels, whereas controls with similarly rapid increases in cellular immune function had IL-6 levels that tended to decrease on ART.

CONCLUSIONS

Rapid expansion of tuberculosis-specific polyfunctional CD4(+) T-cell responses, likely linked to increases in IL-6, is associated with development of paradoxical TB-IRIS.

Immunological profiling of tuberculosis-associated immune reconstitution inflammatory syndrome and non-immune reconstitution inflammatory syndrome death in HIV-infected adults with pulmonary tuberculosis starting antiretroviral therapy: a prospective observational cohort study

BACKGROUND

Patients co-infected with advanced HIV and tuberculosis are at risk of tuberculosis-associated immune reconstitution inflammatory syndrome (IRIS) and death soon after initiation of antiretroviral therapy (ART). Tuberculosis-associated IRIS has been associated with quicker recovery of cellular immune responses after ART initiation and early mortality with slower recovery of these responses. We aimed to assess whether patients who have these outcomes have distinct immunological profiles before and after ART initiation.

METHODS

We undertook this prospective cohort study at 22 public clinics and the main public hospital in Gaborone, Botswana, in ART-naive adults (aged ≥21 years) with advanced HIV (CD4 cell counts ≤125 cells per μL) and pulmonary tuberculosis. We obtained data for clinical variables and for levels of 29 plasma biomarkers, quantified by Luminex assay. We classified patients as having tuberculosis-associated IRIS, early mortality, or survival without a diagnosis of tuberculosis-associated IRIS (controls), on the basis of outcomes recorded in the 6 months after ART initiation. We used rank-sum or χ(2) tests, and logistic regression with odds ratios (OR) and 95% CIs, to assess the association between variables measured before and 4 weeks after ART initiation with death and tuberculosis-associated IRIS, compared with controls.

FINDINGS

Between Nov 12, 2009, and July 3, 2013, we enrolled 201 participants. 31 (15%) patients left the study before ART initiation, leaving 170 (85%) patients for analysis. Patients with tuberculosis-associated IRIS had reduced pre-ART concentrations of several pro-inflammatory biomarkers, including interleukin (IL)-6 (adjusted OR per 1 log10 increase 0·40 [95% CI 0·18-0·89]). However, patients with early death had increased pre-ART concentrations of inflammatory biomarkers, including monocyte chemoattractant protein-1 (adjusted OR 9·0 [95% CI 1·0-80·0]) and tumour necrosis factor (TNF)α (7·8 [1·1-55·2]). At week 4 after ART initation, tuberculosis-associated IRIS was independently associated with greater increases in several inflammatory biomarkers, including IL-6 (adjusted OR 1·7 [95% CI 1·2-2·5]) and TNFα (1·5 [1·0-2·2]), versus controls. Death was likewise associated with greater increases in systemic inflammatory markers, including granulocyte colony-stimulating factor (adjusted OR 2·8 [95% CI 1·3-6·1]), IL-12p40 (1·8 [1·0-3·4]), and IL-15 (2·0 [1·1-3·7]), versus controls. However, changes in CD4 cell count during ART, which were similar between controls and patients with tuberculosis-associated IRIS (p=0·45), were substantially lower in patients who died (p=0·006).

INTERPRETATION

Distinct immunological profiles before and after ART initiation characterise patients with advanced HIV and tuberculosis who have tuberculosis-associated IRIS and death. Interventions that decrease inflammation while promoting cellular immune recovery during ART should be considered in patients co-infected with HIV and tuberculosis.

FUNDING

National Institutes of Health and the Penn Center for AIDS Research.

Screening for pulmonary tuberculosis in HIV-infected individuals: AIDS Clinical Trials Group Protocol A5253

BACKGROUND

Improved tuberculosis (TB) screening is urgently needed for human immunodeficiency virus (HIV) infected patients.

METHODS

An observational, multi-country, cross-sectional study of HIV-infected patients to compare a standardized diagnostic evaluation (SDE) for TB with standard of care (SOC). SOC evaluations included TB symptom review (current cough, fever, night sweats and/or weight loss), sputum Ziehl-Neelsen staining and chest radiography. SDE screening added extended clinical signs and symptoms and fluorescent microscopy (FM). All participants underwent all evaluations. Mycobacterium tuberculosis on sputum culture was the primary outcome.

RESULTS

A total of 801 participants were enrolled from Botswana, Malawi, South Africa, Zimbabwe, India, Peru and Brazil. The median age was 33 years; 37% were male, and median CD4 count was 275 cells/mm(3). Thirty-one participants (4%) had a positive culture on Löwenstein-Jensen media and 54 (8%) on MGIT. All but one positive culture came from sub-Saharan Africa, where the prevalence of TB was 54/445 (12%). SOC screening had 54% sensitivity (95%CI 40-67) and 76% specificity (95%CI 72-80). Positive and negative predictive values were respectively 24% and 92%. No elements of the SDE improved the predictive values of SOC.

CONCLUSIONS

Symptom-based screening with smear microscopy was insufficiently sensitive. More sensitive diagnostic testing is required for HIV-infected patients.

Impact of the human immunodeficiency virus on early multidrug-resistant tuberculosis treatment outcomes in Botswana

SETTING

The impact of the human immunodeficiency virus (HIV) on multidrug-resistant tuberculosis (MDR-TB) treatment outcomes in sub-Saharan Africa, where extensive rollout of highly active antiretroviral therapy (HAART) has occurred, remains unclear.

OBJECTIVE

To compare the time to initial culture conversion among patients with and those without HIV infection in a setting of individualized MDR-TB care in Botswana.

DESIGN

Prospective cohort study of MDR-TB patients receiving ambulatory, integrated TB-HIV care at two public clinics in Botswana. The time to culture conversion was compared by HIV status using Cox proportional hazard ratios (HRs).

RESULTS

A total of 40 HIV-infected and 30 non-HIV-infected patients with MDR-TB and follow-up cultures were identified. The median time to initial culture conversion was 78 days (interquartile range [IQR] 42-186) for HIV-infected and 95 days (IQR 70-133) for non-HIV-infected individuals (log rank P > 0.5; unadjusted HR 0.9, 95%CI 0.5-1.5). Adjusting for age, sex, treatment history and number of active anti-tuberculosis drugs did not change this result (adjusted HR 0.8, 95%CI 0.4-1.4).

CONCLUSION

We found no difference in the proportion of or time to initial sputum culture conversion between an HIV-infected and a non-infected cohort of MDR-TB patients in Botswana, suggesting that outcomes may be comparable in similar settings with access to individualized anti-tuberculosis treatment and HAART.

Isoniazid-resistant tuberculous meningitis, United States, 1993-2005

To determine patient characteristics associated with isoniazid resistance in cases of tuberculous meningitis, we conducted a cross-sectional study by using data from the US National Tuberculosis Surveillance System during 1993–2005. Foreign-born patients were more likely to be infected with an isoniazid-resistant strain.

Cryptococcus and lymphocytic meningitis in Botswana

We retrospectively reviewed microbiological data from a tertiary care hospital in Botswana, and found that Cryptococcus neoformans was cultured from 15% (193/1307) of all cerebrospinal fluid (CSF) specimens submitted for analysis, making it the most common diagnosed cause of meningitis in this population. Moreover, almost 70% of CSF samples with significant lymphocytosis did not yield a pathogen, suggesting that many causes of lymphocytic meningitis go undiagnosed.

Serological evidence of HIV-associated infection among HIV-1-infected adults in Botswana

In industrialized countries, it is recommended that adults with human immunodeficiency virus type 1 (HIV-1) infection undergo baseline screening for pathogens that might cause latent or active infections, such as syphilis, hepatitis B, hepatitis C, infection due to Toxoplasma gondii, and cytomegalovirus infection. A paucity of data exist from sub-Saharan Africa describing the prevalence of these pathogens. We report data for HIV-1-infected adults referred for initiation of highly active antiretroviral therapy in Botswana.

Small rat islets are superior to large islets in in vitro function and in transplantation outcomes

Barriers to the use of islet transplantation as a practical treatment for diabetes include the limited number of available donor pancreata. This project was designed to determine whether the size of the islet could influence the success rate of islet transplantations in rats. Islets from adult rats were divided into two groups containing small (diameter <125 microm) or large (diameter >150 microm) islets. An average pancreas yielded three times more small islets than large. Smaller islets were approximately 20% more viable, with large islets containing a scattered pattern of necrotic and apoptotic cells or central core cell death. Small islets in culture consumed twice as much oxygen as large islets when normalized for the same islet equivalents. In static incubation, small islets released three times more insulin under basal conditions than did large islets. During exposure to high glucose conditions, the small islets released four times more insulin than the same islet equivalencies of large islets, and five times more insulin was released by the small islets in response to glucose and depolarization with K+. Most importantly, the small islets were far superior to large islets when transplanted into diabetic animals. When marginal islet equivalencies were used for renal subcapsular transplantation, large islets failed to produce euglycemia in any recipient rats, whereas small islets were successful 80% of the time. The results indicate that small islets are superior to large islets in in vitro testing and for transplantation into the kidney capsule of diabetic rats.

Management of Potential Neurocysticercosis in Patients with HIV Infection

In patients with human immunodeficiency virus, the diagnosis of neurocysticercosis can be complex, and the current diagnostic criteria may not apply. We report 3 cases and suggest including the CD4+ T lymphocyte count as an important factor in the proper diagnosis and treatment of patients with human immunodeficiency virus and potential neurocysticercosis.

IL-13 Acutely Augments HIV-Specific and Recall Responses from HIV-1-Infected Subjects In Vitro by Modulating Monocytes

We show in this study that acute exposure of PBMCs derived from HIV-infected subjects to IL-13 results in increased recall T cell lymphoproliferative responses against HIV-1 p24 (n = 30, p < 0.0001) and other recall Ags (influenza, n = 43, p < 0.0001; purified protein derivative tuberculin, n = 6, p = 0.0299). This effect is due to a mechanism that acutely targets APC function in the adherent monocyte subset, as shown by the expansion of CD4(+) T cell responses following coculture of IL-13-treated enriched CD14(+) monocytes with donor-matched enriched CD4(+) T cells and Ag. Exposure to IL-13 over 18-72 h resulted in a significant enhancement of monocyte endocytosis (n = 11, p = 0.0005), CD86 expression (n = 12, p = 0.001), and a significant decrease in spontaneous apoptosis (n = 8, p = 0.008). Moreover, IL-13 exposure induced a significant decrease of significantly elevated constitutive levels of PBMC-secreted TNF-alpha (n = 14, p < 0.001) and IL-10 (n = 29, p < 0.001) within 18 h of exposure ex vivo, also reflected by decreased gene expression in the adherent cell population. Our data show that IL-13 is able to acutely enhance the function of the CD14(+) cell subset toward supporting Ag-specific cell-mediated responses in chronic HIV-1 infection.

A tale of 2 epidemics: the intersection between obesity and HIV infection in Philadelphia

BACKGROUND

Obesity and HIV infection are ongoing epidemics in the United States. Obesity predisposes to diabetes and cardiovascular disease, which are complications also associated with HIV and/or its treatment.

OBJECTIVE

To determine the prevalence and risk factors for overweight and obesity in HIV-infected individuals.

DESIGN AND SETTING

Retrospective cross-sectional study in which 1689 patients enrolled in the University of Pennsylvania Center for AIDS Research Adult/Adolescent Database at 1 university hospital clinic, 2 affiliated practices, and 1 Veterans Administration clinic in Philadelphia had demographic, social, and medical data collected prospectively since 1999.

PARTICIPANTS

Body mass index (BMI) data were available for 1669 HIV-infected subjects: 78% were men, and 60% were African American. The median CD4 count was 381 cells/microL, 47% of subjects had a viral load <400 copies/mL, and 9% of subjects were treatment naive.

MAIN OUTCOME MEASURES

The prevalence and risk factors for overweight (BMI: 25-29.9 kg/m) and obesity (BMI>or=30 kg/m) in HIV-infected subjects.

RESULTS

Obesity and overweight were more prevalent than wasting (14%, 31%, and 9%, respectively; P<0.0005), but they were not more common than in the general population. Although women and men were equally overweight (30% vs. 31%), women were more obese than men (28% vs. 11%; P<0.001). Among women, African American race (odds ratio [OR]=1.8, 95% confidence interval [CI]: 1.1-2.9) and a CD4 count>or=200 cells/microL (OR=2.8, 95% CI: 1.6-4.9) were associated with overweight and obesity. Among men, only a CD4 count>or=200 cells/microL (OR=1.6, 95% CI: 1.04-2.4) was associated with increased BMI. In men and women, smoking was associated with decreased obesity and overweight (OR=0.59, 95% CI: 0.47-0.74 and OR=0.65, 95% CI: 0.43-0.98, respectively). Age, income, employment, education, past or current intravenous drugs, being on HIV treatment, and viral load were not associated with obesity in the multivariate model. There was a positive correlation between BMI and total cholesterol, triglycerides, and glucose.

CONCLUSION

Obesity is more common than wasting in this therapeutic era. Women, particularly those of African American race, are at high risk. Obesity might add to metabolic abnormalities associated with HIV or its treatment and contribute to morbidity, as patients with HIV live longer.

Clinical, microbiological, and immunological characteristics in HIV-infected subjects at risk for disseminated Mycobacterium avium complex disease: an AACTG study

The clinical, microbiologic, and immunologic parameters in HIV-infected subjects first presenting with disseminated Mycobacterium avium complex (DMAC) were determined. Four HIV-positive groups not yet on DMAC treatment were enrolled: 19 subjects with CD4 lymphocyte counts < or =50/microl thought to have DMAC on clinical grounds; 18 subjects newly found to have a positive blood culture for MAC; 25 asymptomatic controls (CD4 cell counts < or =50); and 25 asymptomatic controls (CD4 counts 100-250/microl). Outcome measures include comparisons between groups for clinical characteristics; results of cultures from blood, marrow, and gastrointestinal and respiratory tracts; immunological markers from staining of marrow and flow cytometry of circulating lymphocytes; and cytokine production of PBMCs. Only 21% of the 19 patients entered on suspicion of having DMAC grew MAC from blood or marrow. Neither clinical presentation nor laboratory tests differentiated those culture-positive from those culture-negative patients. However, prior PCP or multiple other opportunistic infections were more common in the DMAC group. MAC was isolated from 82% of marrow and 50% of blood specimens from the DMAC group. Respiratory or gastrointestinal colonization was present in 36% of DMAC subjects, but only 5% of non-DMAC subjects with CD4 counts <50 cells/microl. CD8+ cells were more frequent in bone marrow, and CD4 cells recognizing MAC antigen were more frequent in blood from DMAC subjects vs. controls. Results suggest an early stage of tissue dissemination preceding persistent bacteremia, and mucosal entry without persistence of colonization. MAC-specific T cell responses apparently develop and persist during DMAC, but are dysfunctional or too infrequent to prevent persistence.

Plasmid vaccination of stable HIV-positive subjects on antiviral treatment results in enhanced CD8 T-cell immunity and increased control of viral ?blips?

Antiviral therapy prolongs suppression of viral replication and allows for significant immune reconstitution but has not been effective in eradicating reservoirs of virus, which produce resurgent viremia when highly active antiretroviral therapy (HAART) is discontinued. Immune-based therapy may provide an additional antiviral effect. We vaccinated stable HIV-positive patients on HAART with an HIV plasmid vaccine to determine safety, immunogenicity, and therapeutic potential. Volunteers received a combination of two HIV DNA plasmid constructs, which drive expression of env/rev and gag/pol genes. The vaccine was well tolerated with no toxicity. CD4 and CD8 lymphocyte counts did not change significantly among volunteers. CD8 MHC class I-restricted responses to HIV antigens were assayed. Eight of 13 vaccinees responded after vaccination with detectable ELISpot result. Importantly, we observed a difference in viral detection events in vaccinated compared to control patients. Three out of the five placebo recipients had "viral blips" (transient elevations of HIV RNA) during follow-up (10/49 assays) while these were only present in one of 13 vaccinees on one occasion (1/130 assays; p<0.04). The decrease in the frequency of transient viremia and failure suggests that DNA immunization with CD8-generating vaccines in HAART-controlled HIV-positive subjects may have therapeutic potential.

Stavudine Entry into Cerebrospinal Fluid After Single and Multiple Doses in Patients Infected with Human Immunodeficiency Virus

STUDY OBJECTIVE

To establish the pharmacokinetics of stavudine within the cerebrospinal fluid (CSF) of patients infected with human immunodeficiency virus (HIV).

DESIGN

Pharmacokinetic study.

SETTING

General clinical research center.

PATIENTS

Thirty-six patients infected with HIV; 21 were receiving long-term stavudine therapy, 15 were not (single-dose treatment group).

INTERVENTION

After an overnight fast, all patients received a single dose of stavudine 40 mg. Fifteen patients in the long-term treatment group and all 15 patients in the single-dose treatment group were randomized to undergo lumbar puncture 2, 4, or 6 hours after dosing (five patients for each time point from each group). The six other patients in the long-term treatment group underwent lumbar puncture 0 or 8 hours after dosing.

MEASUREMENTS AND MAIN RESULTS

Serum stavudine concentrations were obtained just before dosing, 1 hour after dosing (approximate peak), and at the time of lumbar puncture. The CSF was also analyzed for cell counts, protein, and glucose levels. The mean peak serum stavudine concentration in the long-term treatment group was estimated to be 580.7 ng/ml (2.59 micromol/L), occurring approximately 1.3 hours after dosing. The CSF concentrations over 0-8 hours were 0.0-109.9 ng/ml (0.00-0.49 micromol/L) with an overall mean of 51.6 ng/ml (0.23 micromol/L). Mean peak CSF concentration was estimated to be 62.8 ng/ml (0.28 micromol/L), occurring 4.7 hours after dosing. For the 15 patients not taking stavudine, both the serum and the CSF estimated peaks were significantly lower than those of the long-term group: 475.3 ng/ml (2.12 micromol/L) and 40.4 ng/ml (0.18 micromol/L), respectively. However, time to peak was similar at 1.2 hours and 5.0 hours, respectively. In both groups, no correlation was found between CSF and baseline or peak serum stavudine concentrations, CSF white blood cell count, baseline CD4 + lymphocyte count, or plasma viral load.

CONCLUSION

Mean CSF stavudine concentrations equaled or exceeded the mean concentration producing 50% of the maximal effect in vivo (EC 50 ) for HIV. The CSF concentrations were higher in the stavudine-experienced patients, indicating that concentrations rise with progressive doses until steady state is reached.

Differential virulence of Mycobacterium avium strains isolated from HIV-infected patients with disseminated M. avium complex disease

The role that colonization with Mycobacterium avium plays in the development of disseminated disease is unclear. In this study, we determined whether all M. avium strains isolated from the portals of M. avium infection are capable of crossing the mucosal border and causing infection. The patients in this study were enrolled in AIDS Clinical Trial Group protocol 341. The patients were divided into 3 groups; 2 groups differed in their immunological and clinical risk for M. avium disease. A third group (n=22 patients) had culture-documented disseminated M. avium complex disease at the time of entry in the study. Eight of 22 patients had M. avium isolated from both a colonized site and blood or bone marrow specimens. All 8 patients had distinct M. avium strains; 2 patients had a polyclonal infection. The virulence properties of 13 strains were determined, including invasion of gastrointestinal cells and replication in macrophages. There were significant differences in the virulence properties, and these differences may provide insight into the interplay between microbial pathogenesis and host defense.

Identifying the vector of Lyme disease

Lyme disease is the most common vector-borne illness in the United States. It is caused by the spirochete Borrelia burgdorferi, which is transmitted by the deer tick. Deer ticks have a four-stage life cycle (egg, larva, nymph, and adult), and nymphal ticks transmit B. burgdorferi to humans more frequently than adult ticks. Transmission of this spirochete typically requires a minimum of 24 to 48 hours of tick attachment. Early stages of Lyme disease are characterized by a hallmark rash, erythema migrans. The overall risk of acquiring Lyme disease is low in a person who has a deer tick bite. If erythema migrans develops at the site of the bite, treatment may include doxycycline in persons who are at least eight years of age. Administration of amoxicillin is appropriate for pregnant women or children younger than eight years. For those who are allergic to these medications, cefuroxime axetil may be used.

A prospective, randomized trial examining the efficacy and safety of clarithromycin in combination with ethambutol, rifabutin, or both for the treatment of disseminated Mycobacterium avium complex disease in persons with acquired immunodeficiency syndrome

This multicenter, randomized, open-label phase 3 clinical trial compared the safety and efficacy of 3 clarithromycin-containing combination regimens for the treatment of disseminated Mycobacterium avium complex (MAC) disease in persons with acquired immunodeficiency syndrome. A total of 160 eligible patients with bacteremic MAC disease were randomized to receive clarithromycin with either ethambutol (C+E), rifabutin (C+R), or both (C+E+R) for 48 weeks. After 12 weeks of treatment, the proportion of subjects with a complete microbiologic response was not statistically significantly different among treatment arms: the proportion was 40% in the C+E group, 42% in the C+R group, and 51% in the C+E+R group (P=.454). The proportion of patients with complete or partial responses who experienced a relapse while receiving C+R (24%) was significantly higher than that of patients receiving C+E+R (6%; P=.027) and marginally higher than that of patients receiving C+E (7%; P=.057). Subjects in the C+E+R group had improved survival, compared with the C+E group (hazard ratio [HR], 0.44; 95% confidence interval [CI], 0.23-0.83) and the C+R group (HR, 0.49; 95% CI, 0.26-0.92).

A study of discontinuing maintenance therapy in human immunodeficiency virus-infected subjects with disseminated Mycobacterium avium complex: AIDS Clinical Trial Group 393 Study Team

The present nonrandomized prospective study evaluated whether antimycobacterial therapy for disseminated Mycobacterium avium complex (MAC) could be withdrawn from human immunodeficiency virus-infected subjects who experienced immunologic recovery while receiving highly active antiretroviral therapy (HAART). Eligible subjects had received macrolide-based therapy for least 12 months, were asymptomatic for MAC, had received HAART for at least 16 weeks, and had CD4+ T cell counts >100 cells/microL. Forty-eight subjects were enrolled, with a median CD4+ T cell count of 240 cells/microL at the time of discontinuation of MAC therapy. Forty-seven subjects remained MAC free, whereas 1 subject developed localized MAC osteomyelitis. The median duration of follow-up while not receiving therapy was 77 weeks, and the incidence of MAC infection was 1.44/100 person-years (95% confidence interval, 0.04-8.01). Withdrawal of anti-MAC therapy appears to be safe in patients who have been treated with a macrolide-based regimen for at least 1 year and have an immunologic response on HAART.

Endemic babesiosis in another eastern state: New Jersey

In the United States, most reported cases of babesiosis have been caused by Babesia microti and acquired in the northeast. Although three cases of babesiosis acquired in New Jersey were recently described by others, babesiosis has not been widely known to be endemic in New Jersey. We describe a case of babesiosis acquired in New Jersey in 1999 in an otherwise healthy 53-year-old woman who developed life-threatening disease. We also provide composite data on 40 cases of babesiosis acquired from 1993 through 2001 in New Jersey. The 40 cases include the one we describe, the three cases previously described, and 36 other cases reported to public health agencies. The 40 cases were acquired in eight (38.1%) of the 21 counties in the state. Babesiosis, a potentially serious zoonosis, is endemic in New Jersey and should be considered in the differential diagnosis of patients with fever and hemolytic anemia, particularly in the spring, summer, and early fall.

T-cell responses induced in normal volunteers immunized with a DNA-based vaccine containing HIV-1 env and rev

OBJECTIVE

An effective HIV-1 vaccine will likely need to induce strong cell-mediated immunity in humans. Therefore, we examined the ability of a DNA HIV-1 vaccine to induce a T-cell response in HIV-1 seronegative humans.

DESIGN

Individuals were enrolled in a phase I clinical trial of safety and immune responses to an env/rev-containing plasmid at doses of 100, 300 or 1000 microg. Peripheral blood mononuclear cells (PBMC) samples were analyzed by standard lymphocyte proliferation, cytotoxic T lymphocyte (CTL) and ELISPOT techniques.

RESULTS

PBMCs from subjects immunized with doses as low as 300 microg proliferated in vitro to env (four of six) or (three of six) proteins. Importantly, when the dose of vaccine was increased to 1000 microg of DNA, lymphocytes secreted IFN-gamma in an ELISPOT assay following in vitro stimulation with env (three of six) or rev (four of six) proteins.

CONCLUSION

We observed HIV-1 DNA plasmid vaccines induce CD4 T-helper cell responses in humans. We observed a discrepancy in the CD4 versus CD8 response suggesting the importance of analyzing both compartments in clinical evaluation. Furthermore, this report demonstrates the high level of immunogenicity of and its importance as a component of a prophylactic vaccine for HIV-1.

Clinical protocol. A phase 1 open-label clinical trial of the safety and tolerability of single escalating doses of autologous CD4 T cells transduced with VRX496 in HIV-positive subjects

The proposed study is a Phase I trial to evaluate a HIV-based lentiviral vector carrying an antisense sequence targeted to HIV in the treatment of HIV infection. The primary objective of this Phase I study is to determine the safety and tolerability of treatment with autologous CD4+ T cells modified (transduced) ex vivo with VRX496 when administered to HIV-infected patients. VRX496 is a completely gutted lentiviral vector and does not code for any viral proteins. The viral vector contains an antisense sequence targeted to the HIV envelope (env) gene. VRX496 directly interferes with wild-type HIV (wt-HIV) expression via anti-env antisense expression in vector transduced CD4 cells that become infected with wt-HIV. Expression of the anti-HIV antisense env from a HIV vector transcript would target wt-HIV RNA and destroy it, and hence, decrease productive HIV replication from CD4 T cells. The clinical goal for this treatment approach is to decrease viral loads and promote CD4 T cell survival in vivo. Data from in vitro studies suggest that HIV vectors such as VRX496 could potentially reduce viral loads in HIV-infected individuals and thus could delay the onset to AIDS while promoting CD4 T cell survival and providing the immune system with a better chance to control the infection. Additionally, preliminary results from experiments in SCID mice (mice with transplanted human immune cells) indicate that the human cells transduced with VRX496 and implanted into the SCID mice do not elicit any overt adverse effects. HIV-infected patients (CD4 T cell count of >200/mm3, discontinued from HAART therapy) will undergo leukoapheresis with subsequent CD4 T cell isolation. Patient CD4 T cells will be transduced ex vivo with the vector, expanded for 8-11 days, and then the modified cells will be reintroduced into the patient. Each subject will receive a single intravenous injection infused over 30 minutes; subjects will be examined 24, 48, and 72 hours post-injection and weekly for 4 weeks. Patients will receive one of four different ascending doses (1 x 10(9), 3 x 10(9), 1 x 10(10), and 3 X 10(10) cells/patient). Doses will be administered to four independent, sequential subject cohorts of 3 patients. Groups will be administered escalating doses at 6-week intervals after safety has been demonstrated in the previous group. Follow-up examinations will be conducted 1, 3, and 6 months post-injection. Long term follow-up including RCR testing will be performed.

Species differences in [11C]clorgyline binding in brain

[11C]Clorgyline selectively binds to MAO A in the human brain. This contrasts with a recent report that [11C]clorgyline (in contrast to other labeled MAO A inhibitors) is not retained in the rhesus monkey brain [4]. To explore this difference, we compared [11C]clorgyline in the baboon brain before and after clorgyline pretreatment and we also synthesized deuterium substituted [11C]clorgyline (and its nor-precursor) for comparison. [11C]Clorgyline was not retained in the baboon brain nor was it influenced by clorgyline pretreatment or by deuterium substitution, contrasting to results in humans. This suggests a species difference in the susceptibility of MAO A to inhibition by clorgyline and represents an unusual example of where the behavior of a radiotracer in the baboon brain does not predict its behavior in the human brain.

Increased plasma tryptophan in HIV-infected patients treated with pharmacologic doses of nicotinamide

OBJECTIVE

Decreased plasma tryptophan in persons infected with human immunodeficiency virus (HIV) was first reported over a decade ago, and this observation has since been confirmed by many groups. Before this study, only zidovudine (an antiviral medication) had been reported to reverse plasma tryptophan depletion in HIV-infected persons. Starting with the hypothesis that HIV induces a pellagra-like state and that plasma tryptophan in HIV-infected patients is decreased as a known biochemical correlate of pellagra, we predicted that niacin therapy would reverse plasma tryptophan depletion as it does in pellagra.

METHODS

After receiving approval from the institutional review board, we treated HIV-infected patients for 2 mo with high-dose niacin in the form of oral nicotinamide.

RESULTS

There was an average 40% increase in plasma tryptophan (P = 0.01) in the four HIV-infected individuals who completed the 2-mo protocol. This finding was specific in that four other amino acids, which have been shown to have significant plasma concentration alterations during HIV infection (i.e., cystine, methionine, taurine, and lysine), showed no significant change with nicotinamide therapy.

CONCLUSIONS

There were no adverse side effects attributable to this treatment. The effects of high-dose nicotinamide treatment on morbidity or mortality in HIV-infected persons are yet to be determined. This report marks the first successful use of a vitamin to reverse this HIV-induced metabolic abnormality.

Maintenance of brain monoamine oxidase B inhibition in smokers after overnight cigarette abstinence

OBJECTIVE

The authors' goal was to replicate a previous finding that smokers have lower brain monoamine oxidase B (MAO-B) levels than comparison nonsmoking subjects and to determine if levels recover after overnight cigarette abstinence.

METHOD

Brain MAO-B levels were measured by means of positron emission tomography in six smokers who were scanned twice: 11.3 hours (baseline) and 10 minutes after smoking one cigarette.

RESULTS

Average MAO-B levels in smokers in the present study were similar to those found in the previous study and averaged 39% (SD=17) lower than those found in a comparison group of nonsmokers. Brain MAO-B levels did not differ between baseline levels and 10 minutes after smoking.

CONCLUSIONS

This study reinforces the need to investigate whether MAO-B inhibition may account for some of the behavioral and epidemiological features of smoking.

Effects of Mycobacterium avium complex-infection treatment on cytokine expression in human immunodeficiency virus-infected persons: results of AIDS clinical trials group protocol 853

Human immunodeficiency virus (HIV) type 1-infected persons with newly diagnosed Mycobacterium avium complex (MAC) bacteremia were enrolled in an 8-week study to determine whether treatment of MAC infection is associated with decreases in plasma tumor necrosis factor (TNF)-alpha levels. Blood specimens were obtained for quantitative MAC cultures and to determine plasma levels of HIV RNA, TNF-alpha, and other proinflammatory cytokines. MAC levels decreased by 1.75 log at week 4 (P=.008) and by 2.48 log at week 8 (P=.001). Plasma TNF-alpha decreased by 0.15 log at week 4 (P=.042) and by 0. 40 log at week 8 (P=.027). Plasma interleukin (IL)-6 decreased by 0. 56 log at week 8 (P=.039). There were nonsignificant trends (P<.10) for plasma levels of IL-1beta and HIV RNA to decrease at week 8. Nonsignificant decreases in plasma levels of TNF-alpha, IL-1beta, IL-6, and HIV RNA were also seen in those individuals who remained on stable antiretroviral therapy throughout the 8 weeks of the study.

Induction of tissue plasminogen activator secretion from rat heart microvascular cells by fM 1,25(OH)(2)D(3)

We investigated the effects of 1,25-dihydroxyvitamin D(3) [25(OH)(2)D(3)] on tissue plasminogen activator (tPA) secretion from primary cultures of rat heart microvascular cells. After an initial 5-day culture period, cells were treated for 24 h with 1,25(OH)(2)D(3) and several of its analogs. The results showed that 1,25(OH)(2)D(3) induced tPA secretion at 10(-10) to 10(-16) M. A less calcemic analog, Ro-25-8272, and an analog that binds the vitamin D receptor but is ineffective at perturbing Ca(2+) channels, Ro-24-5531, were approximately 10% as active as 1,25(OH)(2)D(3). An analog that binds the vitamin D receptor poorly but is an effective Ca(2+) channel agonist, Ro-24-2287, required approximately 10(-13) M to induce tPA secretion. Combinations of Ro-24-5531 and Ro-24-2287 were approximately as potent as 1,25(OH)(2)D(3). Treatment of the cells with BAY K 8644 or thapsigargin also increased tPA secretion, suggesting that increased cytosolic calcium concentration ([Ca(2+)]) induces tPA secretion. The results suggested that the sensitivity of the tPA secretory response of microvascular cells to 1,25(OH)(2)D(3) was due in part to generation of a vitamin D-depleted state in vitro and in part to synergistic effects of 1,25(OH)(2)D(3) on two different induction pathways of tPA release.

Vaccination of seronegative volunteers with a human immunodeficiency virus type 1 env/rev DNA vaccine induces antigen-specific proliferation and lymphocyte production of beta-chemokines

There is a pressing need to test novel vaccine concepts in an effort to develop an effective vaccine for human immunodeficiency virus (HIV) type 1. A phase I clinical study was done to test the immunogenicity of an HIV env/rev DNA vaccine, which was administered intramuscularly to HIV-1-seronegative persons. Subjects received 3 doses of vaccine at a single concentration (100 or 300 microgram) at 0, 4, 8, and 24 weeks. In at least 1 of multiple assays, the 6 subjects who received the 300-microgram dose had DNA vaccine-induced antigen-specific lymphocyte proliferative responses and antigen-specific production of both interferon-gamma and beta-chemokine. Furthermore, 4 of 5 subjects in the 300 microgram-dose group responded to both the rev and env components of the vaccine. The responses did not persist within inoculated individuals and scored in different individuals at different times in the trial. This study supports that HIV-1 DNA vaccine antigens can stimulate multiple immune responses in vaccine-naive individuals, and it warrants additional studies designed to enhance DNA vaccine immunogenicity.

Reproducibility of repeated measures of deuterium substituted [11C]L-deprenyl ([11C]L-deprenyl-D2) binding in the human brain

The purpose of this study was to assess the reproducibility of repeated positron emission tomography (PET) measures of brain monoamine oxidase B (MAO B) using deuterium-substituted [11C]L-deprenyl ([11C]L-deprenyl-D2) in normal subjects and to validate the method used for estimating the kinetic constants from the irreversible 3-compartment model applied to the tracer binding. Five normal healthy subjects (age range 23-73 years) each received two PET scans with [11C]L-deprenyl-D2. The time interval between scans was 7-27 days. Time-activity data from eight regions of interest and an arterial plasma input function was used to calculate lambda k3, a model term proportional to MAO B, and K1, the plasma to brain transfer constant that is related to blood flow. Linear (LIN) and nonlinear least-squares (NLLSQ) estimation methods were used to calculate the optimum model constants. A comparison of time-activity curves for scan 1 and scan 2 showed that the percent of change for peak uptake varied from -18.5 to 15.0% and that increases and decreases in uptake on scan 2 were associated with increases and decreases in the value of the arterial input of the tracer. Calculation of lambda k3 showed a difference between scan 1 and scan 2 in the global value ranging between -6.97 and 4.5% (average -2.1 +/- 4.7%). The average percent change for eight brain regions for the five subjects was -2.84 +/- 7.07%. Values of lambda k3 for scan 1 and scan 2 were highly correlated (r2 = 0.98; p < 0.0001; slope 0.955). Similarly, values of K1 showed a significant correlation between scan 1 and scan 2 (r2 = 0.61; p < 0.0001; slope 0.638) though the values for scan 2 were generally lower than those of scan 1. There was essentially no difference between the values of model constants calculated using the NLLSQ or LIN methods. Regional brain uptake of [11C]L-deprenyl-D2 varied between scan 1 and scan 2, driven by the differences in arterial tracer input. Application of a 3-compartment model to regional time-activity data and arterial input function yielded lambda k3 values for scan 1 and scan 2 with an average difference of -2.84 +/- 7.07%. Linear regression applied to values of lambda k3 from the LIN and NLLSQ methods validated the use of the linear method for calculating lambda k3.

Azithromycin as treatment for disseminated Mycobacterium avium complex in AIDS patients

This multicenter, randomized, dose-ranging study was performed to determine the safety and efficacy of two different doses of azithromycin for treating disseminated Mycobacterium avium complex (MAC) in patients with AIDS. Eighty-eight AIDS patients with symptoms and blood cultures consistent with disseminated MAC were treated with 600 or 1,200 mg of azithromycin daily for 6 weeks; 62 patients completed the entire 6 weeks of study. Of note, this study was done prior to the time when combination antiretroviral or anti-MAC regimens were the standard of care. Over the 6-week study period, symptomatic improvement was noted in both dose groups. Microbiological responses were comparable, with mean decreases of 1. 5 and 2.0 log CFU/ml in the high- and low-dose groups, respectively. Sterilization of blood cultures occurred in 54% of samples; patients with lower baseline colony counts were more likely to achieve culture negativity. Resistance developed in one patient. Gastrointestinal symptoms were the most common side effects and were more frequent in patients receiving 1,200 mg. Azithromycin is a useful alternative treatment for disseminated MAC infection in AIDS patients. Symptomatic improvement correlates with measurable decreases in mycobacterial load.

Smoking a single cigarette does not produce a measurable reduction in brain MAO B in non-smokers

Positron emission tomography (PET) studies with [11C]L-deprenyl-D2 have shown that brain monoamine oxidase (MAO) B is 40% lower in smokers than in non-smokers. Here we investigated whether MAO B inhibition can be detected after smoking a single cigarette. Eight normal healthy non-smokers (35 +/- 11 years) received two PET studies 2 h apart with [11C]L-deprenyl-D2, one at baseline and the second 5-10 min after the subject had smoked a single cigarette. Plasma nicotine and expired carbon monoxide (CO) were measured prior to smoking and 10 min after smoking completion as an index of tobacco smoke exposure. A three-compartment model was used to calculate lambda k3, a model term which is proportional to MAO B activity and which is derived from the time course of carbon-11 in the brain and the time course of the radiotracer in the plasma and K1, the plasma-to-brain transfer constant (for [11C]L-deprenyl-D2) which is related to brain blood flow. Subjects experienced difficulty inhaling and became dizzy and/or nauseous after smoking. Plasma nicotine averaged 11.6 +/- 5.5 ng/ml and expired CO averaged 8 +/- 10 ppm after smoking. The average lambda k3 and K1 for 11 different brain regions did not differ significantly between baseline and smoking. These results indicate that the reduction in MAO B in smokers probably occurs gradually and requires chronic tobacco smoke exposure.

HIV-1 DNA vaccines and chemokines

DNA vaccines have a demonstrated ability to induce humoral and cellular immune responses in animal models and humans. The technology, although it dates back to the 1950's, has had an insurgence of interest within the past few years following concurrent research papers. The basic technology is being applied broadly to viral, bacterial and parasitic infections. It has also been demonstrated that genes delivered via plasmid expression vectors result in expression of functional proteins in the inoculated host. Further, injection of plasmids encoding cytokine, chemokine or co-stimulatory molecules, also referred to as immunomodulatory plasmids can lead to the further expansion of this technology to include directed immunology. We have been developing DNA technology specifically with a focus as a vaccine against HIV-1 infection. We report that such vaccines can stimulate immune responses in a variety of relevant animal systems including humoral and cellular responses as well as the production of beta-chemokines. We describe that the beta-chemokines can both modulate the immune response induced by DNA vaccines and be modulated by the DNA vaccines in the murine and chimpanzee models as well as in humans.

Enhancement of cellular immune response in HIV-1 seropositive individuals: A DNA-based trial

A DNA-based vaccine containing HIV-1 Env and Rev genes was tested for safety and host immune response in 15 HIV-infected asymptomatic patients with CD4-positive lymphocyte counts >/=500/microl of blood and receiving no antiviral therapy. Successive groups of patients received three doses of vaccine at 30, 100, or 300 microg at 10-week intervals in a dose-escalation trial. Some changes were noted in cytotoxic T-lymphocyte activity against gp160-bearing targets. Importantly, enhanced specific lymphocyte proliferative activity against HIV-1 envelope was observed in multiple patients. Three of three patients in the 300-microg dose group also developed increased MIP-1alpha levels which were detectable in their serum. Interestingly patients in the lowest dose group showed no overall changes in the immune parameters measured. The majority of patients who exhibited increases in any immune parameters were contained within the 300 microg, which was the highest dose group. These studies support further investigation of this technology for the production of antigen-specific immune responses in humans.

Use of PCR in detection of Mycobacterium avium complex (MAC) bacteremia: sensitivity of the assay and effect of treatment for MAC infection on concentrations of human immunodeficiency virus in plasma

We evaluated the sensitivity and specificity of a PCR-based qualitative test for the rapid diagnosis of Mycobacterium avium-M. intracellulare complex (MAC) bacteremia in patients with AIDS disease. Eleven subjects with newly culture-proven MAC bacteremia had the following tests performed at biweekly intervals during the first 8 weeks of therapy: blood culture, Mycobacterium-specific PCR, and quantitative human immunodeficiency virus (HIV) viral-load testing. Mycobacterium genus-specific biotinylated primers were used to amplify a sequence of approximately 582 nucleotides within the 16S rRNA genes of M. avium and M. intracellulare. Detection of the amplified product was performed with an oligonucleotide probe-coated microwell plate combined with an avidin-horseradish peroxidase-tetramethylbenzidine conjugate-substrate system. While not as sensitive as BACTEC culture, PCR detected 17 of 18 specimens which grew >/=40 organisms/ml (94.4% sensitivity) and 9 of 16 specimens which grew </=40 organisms/ml (56.3% sensitivity). No clear change in HIV viremia occurred in response to successful treatment of patients' MAC bacteremia. Use of the PCR test allowed detection of MAC bacteremia in 1 day, with a sensitivity similar to those of quantitative blood culture techniques, and it may prove useful for rapid screening of suspected cases. HIV viremia was unaffected by 8 weeks of MAC therapy.

HIV-1 DNA based vaccine induces a CD8 mediated cross-clade CTL response

Novel approaches for the generation of more effective vaccines for HIV-1 are of significant importance. In this report we analyse the immunogenicity and efficacy of a DNA vaccination approach in a chimpanzee model system. Three chimpanzees were vaccinated with DNA constructs which express the env, rev, gag and pol proteins. These animals developed specific cellular responses to these proteins, although the nature of the responses varied among the animals. We demonstrated that DNA vaccination led to a CD8 mediated killing of targets expressing the homologous clade B envelope as well as targets expressing heterologous clade E envelope. In addition seronegative individuals have been inoculated with a DNA construct which expresses the env, rev proteins. These studies serve as an important benchmark for the use of DNA vaccine technology for the production of protective immune responses.

Prophylaxis with weekly versus daily fluconazole for fungal infections in patients with AIDS

We compared the efficacy of a 400-mg once-weekly dosage versus a 200-mg daily dosage of fluconazole for the prevention of deep fungal infections in a multicenter, randomized, double-blind trial of 636 human immunodeficiency virus-infected patients to determine if a less intensive fluconazole regimen could prevent these serious but relatively infrequent complications of AIDS. In the intent-to-treat analysis, a deep fungal infection developed in 17 subjects (5.5%) randomly assigned to daily fluconazole treatment and in 24 (7.7%) given weekly fluconazole during 74 weeks of follow-up (risk difference, 2.2%; 95% confidence interval [CI], -1.7% to 6.1%). Thrush occurred twice as frequently in the weekly versus daily fluconazole recipients (hazard ratio, 0.59; 95% CI, 0.40-0.89), and in a subset of patients evaluated, fluconazole resistance was infrequent. Fluconazole administered once weekly is effective in reducing deep fungal infections in patients with AIDS, but this dosage is less effective than the 200-mg-daily dosage in preventing thrush.

First human trial of a DNA-based vaccine for treatment of human immunodeficiency virus type 1 infection: safety and host response

A DNA-based vaccine containing human immunodeficiency virus type 1 (HIV-1) env and rev genes was tested for safety and host immune response in 15 asymptomatic HIV-infected patients who were not using antiviral drugs and who had CD4+ lymphocyte counts of > or = 500 per microliter of blood. Successive groups received three doses of vaccine (30, 100, or 300 microg) at 10-week intervals in a dose-escalation trial. Vaccine administration induced no local or systemic reactions, and no laboratory abnormalities were detected. Specifically, no patient developed anti-DNA antibody or muscle enzyme elevations. No consistent change occurred in CD4 or CD8 lymphocyte counts or in plasma HIV concentration. Antibody against gp120 increased in individual patients in the 100- and 300-/microg groups. Some increases were noted in cytotoxic T lymphocyte activity against gp160-bearing targets and in lymphocyte proliferative activity. The safety and potential immunogenicity of an HIV-directed DNA-based vaccine was demonstrated, a finding that should encourage further studies.

A randomized, double-blind trial of valaciclovir prophylaxis for cytomegalovirus disease in patients with advanced human immunodeficiency virus infection. AIDS Clinical Trials Group Protocol 204/Glaxo Wellcome 123-014 International CMV Prophylaxis Study Group

Cytomegalovirus (CMV) disease is a common complication of advanced human immunodeficiency virus (HIV) infection. Administration of oral valaciclovir, a valine ester of acyclovir, achieves sufficient plasma acyclovir levels to inhibit many clinical isolates. Acyclovir has been associated with enhanced survival in AIDS but not with CMV disease prevention. CMV-seropositive patients (1227) with CD4 cell counts <100/mm3 were enrolled in a randomized, double-blind trial. Valaciclovir, 8 g/day, was compared with acyclovir, 3.2 or 0.8 g/day, for CMV prevention; all three arms were compared for survival. The confirmed CMV disease rate was 11.7% among valaciclovir recipients and 17.5% in the pooled acyclovir arms, a 33% reduction in risk. Time to confirmed CMV disease was significantly longer for the valaciclovir group (P = .03). A trend toward earlier mortality for valaciclovir recipients was seen (P = .06). Toxicity and earlier medication discontinuation were more common in this group. Valaciclovir significantly reduces the risk of CMV disease. Further exploration of a better-tolerated dose is warranted.

Randomized trial of itraconazole oral solution for oropharyngeal candidiasis in HIV/AIDS patients

PURPOSE

Oropharyngeal candidasis (thrush) is the most common opportunistic infection in individuals who are positive for the human immunodeficiency virus (HIV) and those who have progressed to AIDS. Itraconazole has a broad in vitro spectrum of activity, including a wide variety of Candida species. Our study determined the relative efficacy of a new oral solution formulation of itraconazole and fluconazole tablets in the treatment of oropharyngeal candidiasis.

PATIENTS AND METHODS

This was a prospective randomized, third-party-blind, multicenter trial conducted at 12 centers in the United States. One hundred seventy-nine HIV-positive patients with mycologically documented oropharyngeal candidiasis were treated with itraconazole oral solution 200 mg/ day for 7 or 14 days, or fluconazole tablets 100 mg/day for 14 days. Severity of disease was scored clinically before treatment and at clinical evaluations on days 3, 7, 14, 21, 35, and 42. Semi-quantitative cultures of mouth washings were also obtained on these days.

RESULTS

Both 14-day and 7-day regimens of itraconazole oral solution were equivalent to fluconazole for most efficacy parameters. The clinical response rate was 97% after 14 days of itraconazole and 87% after 14 days of fluconazole. Itraconazole oral solution given for 7 days was also equivalent to fluconazole treatment for 14 days. Approximately one half of patients in all three groups relapsed by 1 month after completion of treatment. There were few adverse reactions to either drug.

CONCLUSION

Itraconazole oral solution is well tolerated and offers an alternative at least as effective as fluconazole in the treatment of oropharyngeal candidiasis.

Thapsigargin shifts the Ca set point of parathyroid cells to lower extracellular [Ca]

The hypothesis that cytosolic calcium concentration ([Ca2+cyt]) is the primary regulator of parathyroid hormone (PTH) secretion is supported by a number of studies that show an inverse relationship between them. One agent shown to inhibit PTH secretion is thapsigargin, a sesquiterpene lactone that raises [Ca2+cyt] by inhibiting the Ca-ATPase that pumps Ca2+ from the cytosol into the lumen of the endoplasmic reticulum. Thapsigargin may act on the parathyroid cell other than to inhibit the Ca-ATPase, however, in ways that might also affect PTH secretion. We have tested its effects on functional parameters, such as protein synthesis, the exocytic machinery, and the ability of parathyroid cells to respond to different concentrations of extracellular Ca2+ ([Ca2+ex]). In particular, we have determined whether the inhibition of PTH secretion by thapsigargin is independent of or is modulated by changes in [Ca2+ex]. The results revealed no effects of thapsigargin on protein synthesis or the exocytic mechanisms within 2 h of treatment, and showed that [Ca2+ex] can modulate PTH secretion in the presence of thapsigargin. Its inhibition of PTH secretion, therefore, appears to rest on its ability to shift [Ca2+cyt] to higher levels, but the possibility that it interacts with the Ca receptor has not been eliminated. The results support the hypothesis that the primary regulator of steady-state PTH secretion is [Ca2+cyt].

Secretion of cardiac plasminogen activator during hypoxia-induced right ventricular hypertrophy

In the circulation, fibrinolytic activity is determined to a large degree by the relative levels of tissue plasminogen activator (tPA) and its major inhibitor (PAI-1). Vascular beds in different organs secrete tPA and PAI-1 into the circulation, and the total secretory rate of each protein is balanced by its half-life in the bloodstream. We are testing the hypothesis that in the heart, ventricular hypertrophy will alter the rates of formation of tPA and/or PAI-1 and the rates of their release into the cardiac vasculature. In this study, we have examined the effects of continuous hypoxia on PA activity in extracts of rat heart ventricles, on the activity secreted into the cardiac vasculature of perfused hearts, and on the levels of mRNAs for tPA and PAI-1. Rats were subjected to hypobaric hypoxia at 0.5 atm for 1-21 days. The treatment caused polycythemia within 1-3 days, and right ventricular hypertrophy by 3 days. PA activity in extracts of both right and left ventricles was significantly elevated after 3 days of hypoxia, continued to increase for 4 additional days, and remained elevated for 3 weeks. The actions of inhibitors of urokinase and tPA indicated that the PA activity in heart extracts was exclusively tPA. Fibrin zymography confirmed that result. The mRNAs for tPA and for PAI-1 were elevated after 1 day of hypoxia and then returned to near control levels on days 2 and 3. After 7 days, hearts from hypoxic rats secreted more tPA activity into perfusates than did hearts from controls. The difference in secretory rates was proportional to the differences in the levels of tPA in the corresponding heart extracts.

CCR5 genotypes in sexually active couples discordant for human immunodeficiency virus type 1 infection status

Persons who are homozygous for the delta32 polymorphism of the CCR5 chemokine receptor gene are highly protected against human immunodeficiency virus type 1 (HIV-1) infection. Previous studies described 54 HIV-1-discordant couples in whom no virus transmission occurred despite extensive sexual contact. The possible role of the delta32 polymorphism in the lack of HIV-1 transmission between these partners was studied. No participants were homozygous for the delta32 allele, but the proportion that was heterozygous was higher among HIV-1-seronegative than HIV-1-seropositive partners (28% vs. 11%, P = .05). This association was seen in heterosexual couples (P = .03) but not in homosexual couples (P = .74). Among white persons, who are most likely to carry the delta32 allele, 38.9% of HIV-1-uninfected and 5.6% of HIV-1-infected heterosexual partners were heterozygous (P = .04). These data are consistent with a possible association between the heterozygous delta32 genotype in heterosexual sex partners and partial protection against HIV-1 infection, and they emphasize the importance of analyzing different risk groups in studies of host factors that influence infection.

Oral administration of antibiotics: a rational alternative to the parenteral route

Much early experience with antibiotic therapy involved oral administration of sulfonamides, penicillins, tetracyclines, and chloramphenicol. Newer acid-labile, less-soluble agents created the need for intravenous (i.v.) administration, and i.v. technology (hyporeactive catheter polymers, infusion pumps, etc.) improved to where i.v. administration became normative for the treatment of serious infections. Recently, this preference is being reconsidered in light of agents that are highly effective orally, growing appreciation that i.v. treatment has serious complications, and economic pressures to provide the best care at the lowest cost. This article presents a brief history of administration routes and reviews the rationale for considering oral treatment for serious infections, including consideration of pharmacokinetics and minimum inhibitory concentrations. Published reports supporting the efficacy of orally administered antibiotics either as sole treatment or following an initial parenteral course are reviewed in detail, and examples of programs that educate physicians about the rationale, acceptibility, and benefits of oral administration are given.

Brain monoamine oxidase A inhibition in cigarette smokers

Several studies have documented a strong association between smoking and depression. Because cigarette smoke has been reported to inhibit monoamine oxidase (MAO) A in vitro and in animals and because MAO A inhibitors are effective antidepressants, we tested the hypothesis that MAO A would be reduced in the brain of cigarette smokers. We compared brain MAO A in 15 nonsmokers and 16 current smokers with [11C]clorgyline and positron emission tomography (PET). Four of the nonsmokers were also treated with the antidepressant MAO inhibitor drug, tranylcypromine (10 mg/day for 3 days) after the baseline PET scan and then rescanned to assess the sensitivity of [11C]clorgyline binding to MAO inhibition. MAO A levels were quantified by using the model term lambda k3 which is a function of brain MAO A concentration. Smokers had significantly lower brain MAO A than nonsmokers in all brain regions examined (average reduction, 28%). The mean lambda k3 values for the whole brain were 0.18 +/- 0.04 and 0.13 +/- 0.03 ccbrain (mlplasma)-1 min-1 for nonsmokers and smokers, respectively; P < 0.0003). Tranyl-cypromine treatment reduced lambda k3 by an average of 58% for the different brain regions. Our results show that tobacco smoke exposure is associated with a marked reduction in brain MAO A, and this reduction is about half of that produced by a brief treatment with tranylcypromine. This suggests that MAO A inhibition needs to be considered as a potential contributing variable in the high rate of smoking in depression and in the development of more effective strategies for smoking cessation.

New treatments for new TB strains

Since the discovery of penicillin in the 1930s and antituberculous agents a decade later, antimicrobial chemotherapy has advanced tremendously. New generations of older antibiotics and combinations of drugs have resulted in greater efficacy in the treatment of life-threatening infections. Yet multi-drug resistant tuberculosis remains a threat today, particularly in Pennsylvania.

Safety of dapsone as Pneumocystis carinii pneumonia prophylaxis in human immunodeficiency virus-infected patients with allergy to trimethoprim/sulfamethoxazole

OBJECTIVE

To assess the safety of dapsone prophylaxis of Pneumocystis carinii pneumonia (PCP) in patients with prior intolerance to trimethoprim/sulfamethoxazole (TMP/SMX).

METHODS

We conducted a retrospective study in the categorical human immunodeficiency virus out-patient program of a university hospital. Patients who had filled prescriptions for dapsone at our pharmacy between January 1991 and April 1994 were evaluated and 75 patients were found eligible for analysis.

RESULTS

The overall incidence of adverse events (AE) in our study cohort was 39%. The most common AEs were anemia (23%) and rash (16%). However, after critical evaluation of each case, only 3 cases of anemia (4%) and 2 cases of rash (3%) were judged to be "likely related" to dapsone. Only 5/75 patients (7%) developed the same intolerance to dapsone as previously experienced on TMP/SMX, and none of these cases was viewed as "likely related" to dapsone. A dapsone regimen of 100 mg qd and a prior episode of PCP were associated with a higher incidence of AEs. Eight cases of PCP occurred in spite of dapsone prophylaxis for an incidence of 7 cases per 1,000 patient-months. Seven of the cases of PCP occurred in patients who were receiving secondary prophylaxis.

CONCLUSIONS

Given the low incidence of AEs judged to be "likely related" to dapsone, this drug is a reasonable choice for PCP prophylaxis in patients with prior AEs to TMP/SMX.