Nevirapine pharmacokinetics in HIV-infected persons receiving rifapentine and isoniazid for TB prevention.

BACKGROUND: The use of rifamycin antibiotics for TB prevention carries a risk of detrimental drug-drug interactions with concomitantly used ART. OBJECTIVES: To evaluate the interaction of the antiretroviral drug nevirapine in combination with 4 weeks of daily rifapentine and isoniazid for TB prevention in people living with HIV. METHODS: Participants were individuals enrolled in the BRIEF-TB study receiving nevirapine and randomized to the rifapentine/isoniazid arm of the study. Participants provided sparse pharmacokinetic (PK) sampling at baseline and weeks 2 and 4 for trough nevirapine determination. Nevirapine apparent oral clearance (CL/F) was estimated and the geometric mean ratio (GMR) of CL/F prior to and during rifapentine/isoniazid was calculated. RESULTS: Seventy-eight participants had evaluable PK data: 61 (78%) female, 51 (65%) black non-Hispanic and median (range) age of 40 (13-66) years. Median (IQR) nevirapine trough concentrations were: week 0, 7322 (5266-9302) ng/mL; week 2, 5537 (3552-8462) ng/mL; and week 4, 5388 (3516-8243) ng/mL. Sixty out of 78 participants (77%) had nevirapine concentrations ≥3000 ng/mL at both week 2 and 4. Median (IQR) nevirapine CL/F values were: week 0 pre-rifapentine/isoniazid, 2.03 (1.58-2.58) L/h; and during rifapentine/isoniazid, 2.62 (1.81-3.42) L/h. The GMR (90% CI) for nevirapine CL/F was 1.30 (1.26-1.33). CONCLUSIONS: The CL/F of nevirapine significantly increased with concomitant rifapentine/isoniazid. The decrease in nevirapine trough concentrations during rifapentine/isoniazid therapy suggests induction of nevirapine metabolism, consistent with known rifapentine effects. The magnitude of this drug-drug interaction suggests daily rifapentine/isoniazid for TB prevention should not be co-administered with nevirapine-containing ART.

International neurocognitive normative study: neurocognitive comparison data in diverse resource-limited settings: AIDS Clinical Trials Group A5271.

Infrastructure for conducting neurological research in resource-limited settings (RLS) is limited. The lack of neurological and neuropsychological (NP) assessment and normative data needed for clinical interpretation impedes research and clinical care. Here, we report on ACTG 5271, which provided neurological training of clinical site personnel and collected neurocognitive normative comparison data in diverse settings. At ten sites in seven RLS countries, we provided training for NP assessments. We collected normative comparison data on HIV- participants from Brazil (n = 240), India (n = 480), Malawi (n = 481), Peru (n = 239), South Africa (480), Thailand (n = 240), and Zimbabwe (n = 240). Participants had a negative HIV test within 30 days before standardized NP exams were administered at baseline and 770 at 6 months. Participants were enrolled in eight strata, gender (female and male), education (<10 and ≥10 years), and age (<35 and ≥35 years). Of 2400 enrolled, 770 completed the 6-month follow-up. As expected, significant between-country differences were evident in all the neurocognitive test scores (p < 0.0001). There was variation between the age, gender, and education strata on the neurocognitive tests. Age and education were important variables for all tests; older participants had poorer performance, and those with higher education had better performance. Women had better performance on verbal learning/memory and speed of processing tests, while men performed better on motor tests. This study provides the necessary neurocognitive normative data needed to build infrastructure for future neurological and neurocognitive studies in diverse RLS. These normative data are a much-needed resource for both clinicians and researchers.

Population level usage of health services, and HIV testing and care, prior to decentralization of antiretroviral therapy in Agago District in rural Northern Uganda.

BACKGROUND: Decentralization of ART services scaled up significantly with the country wide roll out of option B plus in Uganda. Little work has been undertaken to examine population level access to HIV care particularly in hard to reach areas in rural Africa. Most work on ART scale up has been done at health facility level which omits people not accessing healthcare in the community. This study describes health service usage, particularly HIV testing and care in 2/6 parishes of Lapono sub-county of northern Uganda, prior to introduction of ART services in Lira Kato Health Centre (a local lower-level health centre III), as part of ART decentralization. METHODS: Household and individual questionnaires were administered to household members (aged 15-59 years). Logit random effects models were used to test for differences in proportions (allowing for clustering within villages). RESULTS: 2124 adults from 1351 households were interviewed (755 [36%] males, 1369 [64 %] females). 2051 (97%) participants reported seeking care locally for fever, most on foot and over half at Lira Kato Health Centre. 574 (76%) men and 1156 (84%) women reported ever-testing for HIV (P < 0.001 for difference); 34/574 (6%) men and 102/1156 (9%) women reported testing positive (P = 0.04). 818/850 (96%) women who had given birth in the last 5 years had attended antenatal care in their last pregnancy: 7 women were already diagnosed with HIV (3 on ART) and 790 (97%) reported being tested for HIV (34 tested newly positive). 124/136 (91%) HIV-positive adults were in HIV-care, 123/136 (90 %) were taking cotrimoxazole and 74/136 (54%) were on ART. Of adults in HIV-care, most were seen at Kalongo hospital (n = 87), Patongo Health Centre (n = 7) or Lira Kato Health Centre (n = 23; no ART services). 58/87, 5/7 and 20/23 individuals walked to Kalongo hospital (56 km round-trip, District Health Office information), Patongo Health Centre (76 km round-trip, District Health Office information) and Lira Kato Health Centre (local) respectively. 8 HIV-infected children were reported; only 2 were diagnosed aged <24 months: 7/8 were in HIV-care including 3 on ART. CONCLUSIONS: Higher proportions of women compared to men reported ever-testing for HIV and testing HIV-positive, similar to other surveys. HIV-infected men and women travelled considerable distances for ART services. Children appeared to be under-accessing testing and referral for treatment. Decentralization of ART services to a local health facility would decrease travel time and transport costs, making care and treatment more easily accessible.

Renal and metabolic toxicities following initiation of HIV-1 treatment regimen in a diverse, multinational setting: a focused safety analysis of ACTG PEARLS (A5175).

BACKGROUND: Convenient dosing, potency, and low toxicity support use of tenofovir disoproxil fumarate (TDF) as preferred nucleotide reverse transcriptase inhibitor (NRTI) for HIV-1 treatment. However, renal and metabolic safety of TDF compared to other NRTIs has not been well described in resource-limited settings. METHODS: This was a secondary analysis examining the occurrence of renal abnormalities (RAs) and renal and metabolic serious non-AIDS-defining events (SNADEs) through study follow-up between participants randomized to zidovudine (ZDV)/lamivudine/ efavirenz and TDF/emtricitabine/efavirenz treatment arms within A5175/PEARLS trial. Exact logistic regression explored associations between baseline covariates and RAs. Response profile longitudinal analysis compared creatinine clearance (CrCl) over time between NRTI groups. RESULTS: Twenty-one of 1,045 participants developed RAs through 192 weeks follow-up; there were 15 out of 21 in the TDF arm (P = .08). Age 41 years or older (odds ratio [OR], 3.35; 95% CI, 1.1-13.1), his- tory of diabetes (OR, 10.7; 95% CI, 2.1-55), and lower baseline CrCl (OR, 3.1 per 25 mL/min decline; 95% CI, 1.7-5.8) were associated with development of RAs. Renal SNADEs occurred in 42 participants; 33 were urinary tract infections and 4 were renal failure/insufficiency; one event was attributed to TDF. Significantly lower CrCl values were maintained among patients receiving TDF compared to ZDV (repeated measures analysis, P = .05), however worsening CrCl from baseline was not observed with TDF exposure over time. Metabolic SNADEs were rare, but were higher in the ZDV arm (20 vs 3; P < .001). CONCLUSIONS: TDF is associated with lower serious metabolic toxicities but not higher risk of RAs, serious renal events, or worsening CrCl over time compared to ZDV in this randomized multinational study.

Improved neuropsychological and neurological functioning across three antiretroviral regimens in diverse resource-limited settings: AIDS Clinical Trials Group study a5199, the International Neurological Study.

BACKGROUND: AIDS Clinical Trials Group (ACTG) A5199 compared the neurological and neuropsychological (NP) effects of 3 antiretroviral regimens in participants infected with human immunodeficiency virus type 1 (HIV-1) in resource-limited settings. METHODS: Participants from Brazil, India, Malawi, Peru, South Africa, Thailand, and Zimbabwe were randomized to 3 antiretroviral treatment arms: A (lamivudine-zidovudine plus efavirenz, n = 289), B (atazanavir, emtricitabine, and didanosine-EC, n = 293), and C (emtricitabine-tenofovir-disoproxil fumarate plus efavirenz, n = 278) as part of the ACTG PEARLS study (A5175). Standardized neurological and neuropsychological (NP) screening examinations (grooved pegboard, timed gait, semantic verbal fluency, and finger tapping) were administered every 24 weeks from February 2006 to May 2010. Associations with neurological and neuropsychological function were estimated from linear and logistic regression models using generalized estimating equations. RESULTS: The median weeks on study was 168 (Q1 = 96, Q3 = 192) for the 860 participants. NP test scores improved (P < .05) with the exception of semantic verbal fluency. No differences in neurological and neuropsychological functioning between treatment regimens were detected (P > .10). Significant country effects were noted on all NP tests and neurological outcomes (P < .01). CONCLUSIONS: The study detected no significant differences in neuropsychological and neurological outcomes between randomized ART regimens. Significant improvement occurred in neurocognitive and neurological functioning over time after initiation of ARTs. The etiology of these improvements is likely multifactorial, reflecting reduced central nervous system HIV infection, better general health, and practice effects. This study suggests that treatment with either of the World Health Organization -recommended first-line antiretroviral regimens in resource-limited settings will improve neuropsychological functioning and reduce neurological dysfunction. CLINICAL TRIALS REGISTRATION: NCT00096824.

The impact of first year adherence to antiretroviral therapy on long-term clinical and immunological outcomes in the DART trial in Uganda and Zimbabwe.

OBJECTIVES: To describe associations between different summaries of adherence in the first year on antiretroviral therapy (ART) and the subsequent risk of mortality, to identify patients at high risk because of early adherence behaviour. METHODS: We previously described an approach where adherence behaviour at successive clinic visits during the first year on ART was seen as a Markov chain (MC), and the individually estimated transition probabilities between 'good', 'poor' and 'non-response' adherence states were used to classify HIV-infected adults in the DART trial into subgroups with similar behaviour. The impact of this classification and classifications based on traditional 'averaged' measures [mean drug possession ratio (DPR) and self-reported adherence] were compared in terms of their impact on longer-term mortality over the 2-5 years on ART using Cox proportional hazards models. RESULTS: Of 2960 participants in follow-up after 1 year on ART, 29% had never missed pills in the last month and 11% had 100% DPR throughout the first year. The poorest adherers by self-reported measures were more likely to have only none/primary education (P < 0.01). Being in the poorest adherence subgroup by MC and DPR was independently associated with increased mortality [HR = 1.57 (95% CI 1.02, 2.42); 1.82 (1.32, 2.51) respectively]. CONCLUSIONS: Classification based on dynamic adherence behaviour is associated with mortality independently of DPR. The classifications could be useful in understanding adherence, targeting focused interventions and improving longer-term adherence to therapy.

Daily co-trimoxazole prophylaxis in severely immunosuppressed HIV-infected adults in Africa started on combination antiretroviral therapy: an observational analysis of the DART cohort.

BACKGROUND: Co-trimoxazole prophylaxis can reduce mortality from untreated HIV infection in Africa; whether benefits occur alongside combination antiretroviral therapy (ART) is unclear. We estimated the effect of prophylaxis after ART initiation in adults. METHODS: Participants in our observational analysis were from the DART randomised trial of management strategies in HIV-infected, symptomatic, previously untreated African adults starting triple-drug ART with CD4 counts lower than 200 cells per muL. Co-trimoxazole prophylaxis was not routinely used or randomly allocated, but was variably prescribed by clinicians. We estimated effects on clinical outcomes, CD4 cell count, and body-mass index (BMI) using marginal structural models to adjust for time-dependent confounding by indication. DART was registered, number ISRCTN13968779. FINDINGS: 3179 participants contributed 14 214 years of follow-up (8128 [57%] person-years on co-trimoxazole). Time-dependent predictors of co-trimoxazole use were current CD4 cell count, haemoglobin concentration, BMI, and previous WHO stage 3 or 4 events on ART. Present prophylaxis significantly reduced mortality (odds ratio 0.65, 95% CI 0.50-0.85; p=0.001). Mortality risk reduction on ART was substantial to 12 weeks (0.41, 0.27-0.65), sustained from 12-72 weeks (0.56, 0.37-0.86), but not evident subsequently (0.96, 0.63-1.45; heterogeneity p=0.02). Variation in mortality reduction was not accounted for by time on co-trimoxazole or current CD4 cell count. Prophylaxis reduced frequency of malaria (0.74, 0.63-0.88; p=0.0005), an effect that was maintained with time, but we observed no effect on new WHO stage 4 events (0.86, 0.69-1.07; p=0.17), CD4 cell count (difference vs non-users, -3 cells per muL [-12 to 6]; p=0.50), or BMI (difference vs non-users, -0.04 kg/m(2) [-0.20 to 0.13); p=0.68]. INTERPRETATION: Our results reinforce WHO guidelines and provide strong motivation for provision of co-trimoxazole prophylaxis for at least 72 weeks for all adults starting combination ART in Africa. FUNDING: UK Medical Research Council, the UK Department for International Development, the Rockefeller Foundation, GlaxoSmithKline, Gilead Sciences, Boehringer-Ingelheim, and Abbott Laboratories.

Routine versus clinically driven laboratory monitoring of HIV antiretroviral therapy in Africa (DART): a randomised non-inferiority trial.

BACKGROUND: HIV antiretroviral therapy (ART) is often managed without routine laboratory monitoring in Africa; however, the effect of this approach is unknown. This trial investigated whether routine toxicity and efficacy monitoring of HIV-infected patients receiving ART had an important long-term effect on clinical outcomes in Africa. METHODS: In this open, non-inferiority trial in three centres in Uganda and one in Zimbabwe, 3321 symptomatic, ART-naive, HIV-infected adults with CD4 counts less than 200 cells per microL starting ART were randomly assigned to laboratory and clinical monitoring (LCM; n=1659) or clinically driven monitoring (CDM; n=1662) by a computer-generated list. Haematology, biochemistry, and CD4-cell counts were done every 12 weeks. In the LCM group, results were available to clinicians; in the CDM group, results (apart from CD4-cell count) could be requested if clinically indicated and grade 4 toxicities were available. Participants switched to second-line ART after new or recurrent WHO stage 4 events in both groups, or CD4 count less than 100 cells per microL (LCM only). Co-primary endpoints were new WHO stage 4 HIV events or death, and serious adverse events. Non-inferiority was defined as the upper 95% confidence limit for the hazard ratio (HR) for new WHO stage 4 events or death being no greater than 1.18. Analyses were by intention to treat. This study is registered, number ISRCTN13968779. FINDINGS: Two participants assigned to CDM and three to LCM were excluded from analyses. 5-year survival was 87% (95% CI 85-88) in the CDM group and 90% (88-91) in the LCM group, and 122 (7%) and 112 (7%) participants, respectively, were lost to follow-up over median 4.9 years' follow-up. 459 (28%) participants receiving CDM versus 356 (21%) LCM had a new WHO stage 4 event or died (6.94 [95% CI 6.33-7.60] vs 5.24 [4.72-5.81] per 100 person-years; absolute difference 1.70 per 100 person-years [0.87-2.54]; HR 1.31 [1.14-1.51]; p=0.0001). Differences in disease progression occurred from the third year on ART, whereas higher rates of switch to second-line treatment occurred in LCM from the second year. 283 (17%) participants receiving CDM versus 260 (16%) LCM had a new serious adverse event (HR 1.12 [0.94-1.32]; p=0.19), with anaemia the most common (76 vs 61 cases). INTERPRETATION: ART can be delivered safely without routine laboratory monitoring for toxic effects, but differences in disease progression suggest a role for monitoring of CD4-cell count from the second year of ART to guide the switch to second-line treatment. FUNDING: UK Medical Research Council, the UK Department for International Development, the Rockefeller Foundation, GlaxoSmithKline, Gilead Sciences, Boehringer-Ingelheim, and Abbott Laboratories.

The incidence of p53 mutations increases with progression of head and neck cancer.

To establish a genetic model of the progression of head and neck squamous carcinoma we have defined the incidence and timing of p53 mutations in this type of cancer. We sequenced the conserved regions of the p53 gene in 102 head and neck squamous carcinoma lesions. These included 65 primary invasive carcinomas and 37 noninvasive archival specimens consisting of 13 severe dysplasias and 24 carcinoma in situ lesions. The incidence of p53 mutations in noninvasive lesions was 19% (7/37) and increased to 43% (28/65) in invasive carcinomas. These data suggest that p53 mutations can precede invasion in primary head and neck cancer. Furthermore, the spectrum of codon hotspots is similar to that seen in squamous carcinoma of the lung and 64% of mutations are at G nucleotides, implicating carcinogens from tobacco smoke in the etiology of head and neck squamous carcinoma.

Oxidative damage to lysozyme by the hydroxyl radical: comparative effects of scavengers.

The hydroxyl radical (OH.) is a highly-damaging reactive oxygen species, given its high reactivity and the consequent generation of secondary free radicals. This study was aimed at determining the qualitative and quantitative aspects of OH. scavenging by pentoxifylline (Ptx, a methylxanthine), uric acid and thymine on the OH.-induced alterations of a protein, lysozyme. Lysozyme was inactivated by OH. with a yield of 6.5 mol OH./mol lysozyme; moreover, SDS-PAGE showed a loss of native lysozyme (14.4 kDa), the presence of dimer and trimer aggregates and characteristic fragmentation. Tryptophan fluorescence was lost before aggregation became detectable in terms of bityrosine formation. Increasing concentrations of OH. scavengers gave increasing protection of lysozyme activity. Although all three compounds scavenge OH. with high rate constants, their effects were different: uric acid and Ptx prevented aggregation and preserved enzyme activity, whereas thymine preserved activity but did not prevent aggregation. These differences appear to be related to the formation of reducing secondary radicals, underlining the importance of this mechanism in the effects of scavengers.

Role of cytochrome b-559 in arachidonic acid activation of resting human neutrophils.

Whether or not cytochrome b-559 is a necessary component of NADPH oxidase activity in neutrophils is still controversial. In highly purified plasma membranes isolated from resting neutrophils and lacking cytochrome b, addition of arachidonic acid induced an NADPH oxidase activity. This activity was similar to that of plasma membranes isolated from phorbol myristate acetate (PMA)-stimulated cells which possessed cytochrome b. Addition of arachidonic acid to the latter plasma membranes did not alter the oxidase activity. It can be concluded that plasma membranes isolated from resting neutrophils have, in the presence of arachidonic acid, an NADPH oxidase activity similar to that of PMA-stimulated cells, except that it is independent of cytochrome b-559.

Resolution of major protein kinase substrates in neutrophil cytosol in response to DAG/PS and arachidonic acid stimulation and the selective action of various protein kinase inhibitors.

Stimulation of human neutrophils induces phosphorylation of several cellular proteins. Human neutrophils possess calcium-dependent protein kinase C (PKC) alpha and beta isoforms and calcium-independent n isoforms. Little is known, however, of the physiological substrates of each isoform. In this study, we characterized the substrates of calcium-dependent and -independent PKC isoforms and the substrate of PKC activated by arachidonic acid. Furthermore, we found that the PKC inhibitor H-7 failed to inhibit phosphorylation of endogenous substrates of calcium-independent PKC activity. These results may help to understand the role of PKC in neutrophil activation and shed light on the different responses elicited by H-7 in intact cells.

Analysis of choline and phosphorylcholine content in human neutrophils stimulated by f-Met-Leu-Phe and phorbol myristate acetate: contribution of phospholipase D and C.

ABSTRACT. We analysed changes in choline (CHO) and phosphorylcholine (PCHO) content of stimulated human polymorphonuclear leukocytes (PMNs) by a chemiluminescence assay to further examine the relative contributions of phospholipase D (PLD) and PLC to phosphatidylcholine (PC) breakdown. PLD activation was also analysed by measuring tritiated phosphatidic acid (PA) and diglycerides (GDs) in PMNs labelled with tritiated alkyl-lyso PC. Stimulation of PMNs with formyl-methionyl-leucyl-phenylalanine fMLP; 0.1 microM induced a weak elevation of mass choline (+25% of basal level) that was strongly potentiated in PMNs primed with cytochalasin B (+350% relative to the control value of 657+/-53 pmol/10(7) cells). CHO production was rapid and transient, peaking within 1 min, and ran parallel to that of tritiated PA. Thereafter, the amount of tritiated PA declined strongly (40% of maximum by 3 min), whereas the elevated choline content induced by fMLP plateaued for at least 5 min. Phorbol myristate acetate (PMA) sustained the formation of CHO for as long as 20 min, which correlated with that of [3H]PA in a time- and concentration-dependent manner. PCHO content of resting PMN leukocytes (1560 +/- 56 pmol/10(7) cells) was not modified after stimulation of PMNs with fMLP or PMA for at least 10 min, which argues against breakdown of phosphatidylcholine by PLC. For longer treatment (10-20 min), fMLP stimulated a significant enhancement of PCHO level, which occurred concomitantly with a decrease in CHO level, suggesting that choline kinase rather than PLC may be activated. Unlike fMLP, PMA stimulated a fall in PCHO between 10 and 15 min after PMN stimulation, pointing to different regulatory mechanisms of PCHO level. These data indicate that DG formation from PC in PMNs is mediated by PLD but not by PLC and show that chemiluminescence measurement of choline is a reliable index of PLD activation.

Priming of phosphatidic acid production by staurosporine in f-Met-Leu-Phe-stimulated human neutrophils--correlation with respiratory burst.

Staurosporine, a microbial alkaloid known as a potent though non specific PKC inhibitor, enhances the production of superoxide anion (respiratory burst) of human polymorphonuclear leukocytes (PMN) stimulated by chemoattractants such as f-Met-Leu-Phe (fMLP). To gain insights into the mechanisms of this priming, we analysed staurosporine effects on formation of second messengers issued from phospholipase D (PLD), i.e., phosphatidic acid (PA) and its dephosphorylated form, diglycerides (DG). PA and DG were measured by two methods, in mass and after the labelling of PMN with a phosphatidylcholine precursor, [3H]-1-O-alkyl-2-lyso-3-phosphatidylcholine. Treatment of labelled PMN with low concentrations of staurosporine (12.5 and 50 nM) which prime respiratory burst had no significant effect on basal amounts of tritiated PA and DG, but potentiated fMLP-mediated formation of [3H]PA and phosphatidylethanol (PEt) pointing to a priming of PLD activity. PA mass in resting PMN increased (approximately 80 +/- 7%) in the presence of high drug concentrations only (250-500 nM), with no change in basal DAG mass. Low staurosporine concentrations (6.25-25 nM) markedly potentiated PA mass formation induced by fMLP and positive correlation (R = 0.95) was found between enhanced superoxide formation and generation of PA but not DG. Furthermore, cytochalasin B, which is known to prime PA production induced by fMLP, synergised the priming of respiratory burst by staurosporine, which further suggests a functional role of PA. In contrast to staurosporine, the more selective PKC inhibitor GF109203X neither stimulated PLD nor primed fMLP-induced PLD or respiratory burst. These data indicate that priming of fMLP-mediated PMN respiratory burst by staurosporine correlates with PA formation. This priming may be linked to alteration of early signalling events upstream of PLD rather than to feedback inhibition of PKC.

P40phox associates with the neutrophil Triton X-100-insoluble cytoskeletal fraction and PMA-activated membrane skeleton: a comparative study with P67phox and P47phox.

NADPH oxidase is an O2*- -generating enzyme found in phagocytes such as neutrophils. It is composed of a membrane-bound cytochrome b, the cytosolic proteins p67phox, p47phox, p40phox, and the G-protein p21rac. The system is dormant in resting cells but acquires catalytic activity on exposure to appropriate stimuli. Cytochrome b, p67phox, p47phox, and rac2 associate with the cytoskeleton and membrane skeleton of activated neutrophils. It is not known whether p40phox associates with the cytoskeleton. The purpose of this study was to analyze the subcellular distribution of p40phox. When resting neutrophils were lysed in Triton X-100 or octyl glucoside buffer and separated into detergent-soluble and detergent-insoluble fractions, p40phox and p67phox were mainly associated with the detergent-insoluble fraction (defined as the cytoskeleton), whereas p47phox was mainly found in the soluble fraction. Neutrophil activation by phorbol myristate acetate (PMA) induced p47phox translocation to the cytoskeleton but did not affect the distribution of p40phox or p67phox. Using immunofluorescence confocal microscopy, we found that p40phox colocalized with filamentous actin. In neutrophils from a p67phox-deficient patient with detectable p40phox, p40phox associated with the cytoskeleton only after activation by PMA. A complex containing the three proteins was isolated from the cytoskeleton of activated neutrophils. When activated membranes were treated with Triton X-100 buffer, p40phox, p47phox, and p67phox were found in the membrane skeleton enriched in NADPH-oxidase activity; some p40phox and p47phox was found in the soluble membrane fraction, but no p67phox was detected. These findings show that p40phox, like p67phox and p47phox, binds to the cytoskeleton and membrane skeleton. In addition, p40phox can dissociate from p67phox in activated membranes.

Rheumatic fever and rheumatic heart disease among children presenting to two referral hospitals in Harare, Zimbabwe.

BACKGROUND: Acute rheumatic fever (ARF) and rheumatic heart disease (RHD) remain significant causes of morbidity and mortality in resource-limited settings. In Zimbabwe ARF/RHD characteristics have not been systematically documented. OBJECTIVES: To document cases of ARF/RHD among children presenting at referral hospitals in Harare, Zimbabwe, determine their clinical and echocardiographic characteristics, and identify opportunities for improving care. METHODS: A cross-sectional survey was carried out in which consecutive children aged 1 - 12 years presenting with ARF/RHD according to the 2002/3 World Health Organization modified Jones criteria were enrolled. RESULTS: Out of 2 601 admissions and 1 026 outpatient visits over 10 months, 50 children were recruited, including 31 inpatients with ARF/RHD and 19 outpatients with chronic RHD. Among inpatients, 9 had ARF only, 7 recurrent ARF with RHD, and 15 RHD only. The commonest valve lesions were mitral regurgitation (26/31) and aortic regurgitation (11/31). The commonest reason for admission was cardiac failure (22/31). The proportion of ARF/RHD cases among inpatients aged 1 - 12 years was 11.9/1 000. Of the 22 with RHD, 14 (63.6%) presented de novo and 1 had bacterial endocarditis. Among the outpatients, 15 had cardiac failure while echocardiographic findings included mitral regurgitation (18/19) and aortic regurgitation (5/19). At presentation, 18/26 known cases were on oral penicillin prophylaxis and 7 on injectable penicillin. Of those on secondary prophylaxis, 68.0% reported taking it regularly. CONCLUSION: ARF/RHD remains a major problem and cause of hospital admissions in Harare, Zimbabwe. Children often present late with established RHD and cardiac failure. With the majority on oral penicillin, secondary prophylaxis was suboptimal in a resource-limited setting unable to offer valve replacement surgery.

Impact of HIV infection on meningitis in Harare, Zimbabwe: a prospective study of 406 predominantly adult patients.

OBJECTIVE: To determine the causative organisms and characteristics of patients presenting with features of meningitis. DESIGN: A prospective cross-sectional study. SETTING: Two tertiary university-affiliated hospitals in Harare, Zimbabwe. PATIENTS: Four-hundred and six patients clinically suspected to have meningitis. MAIN OUTCOME MEASURES: Causative organisms of meningitis; clinical and cerebrospinal fluid characteristics. RESULTS: Four-hundred and six predominantly adult (95% were aged > or = 18 years) patients were suspected to have meningitis. Of the 200 patients confirmed to have meningitis, 89 (45%) had cryptococcal meningitis (CM), 54 (27%) had mononuclear meningitis (MM), 31 (16%) had pyogenic meningitis (PM), 24 (12%) had tuberculous meningitis (TBM) and 2 (1%) had undefined meningitis. HIV seropositivity was 100% in CM, 83% in MM, 81% in PM and 88% in TBM patients. In-hospital mortality rate was 38.8% for CM, 34.9% for MM, 68% for PM and 66.7% for TBM. HIV seropositivity was 80% in the 206 patients not found to have meningitis. CONCLUSIONS: All patients suspected to have meningitis had a high HIV sero positivity irrespective of whether they were later confirmed to have meningitis or not. CM was the most common type of meningitis seen. In-hospital mortality was high irrespective of the cause of meningitis.

Absence of p53 point mutations in parathyroid adenoma and carcinoma.

Primary hyperparathyroidism is a common disorder characterized by aberrant growth and function of solitary or multiple parathyroid glands. Many, if not all, parathyroid adenomas are examples of benign clonal neoplastic growth. The molecular events associated with the development of parathyroid neoplasia have not been well characterized. We examined benign and malignant parathyroid tissues for structural abnormalities of the p53 tumor suppressor gene. To screen for mutations in the p53 gene, we analyzed polymerase chain reaction-amplified DNA by denaturing gradient gel electrophoresis. DNA was isolated from 26 benign parathyroid adenomas and 3 parathyroid carcinomas, and polymerase chain reaction was used to amplify DNA fragments corresponding to the 4 evolutionarily conserved domains within exons 5, 7, and 8 of the p53 gene in which the majority of point mutations have been identified. Amplified DNA fragments were electrophoresed through polyacrylamide gels with linearly increasing gradients of the denaturants urea and formamide. After electrophoresis, the gels were examined for the presence of abnormally migrating bands, which represent DNA with altered melting points due to nucleotide sequence changes. Amplified fragments were of the expected size in DNA from 26 parathyroid adenomas and 3 parathyroid carcinomas. Denaturing gradient gel electrophoresis studies failed to disclose evidence of mutations in exons 5, 7, and 8 of the p53 gene in these neoplasms. We conclude that p53 point mutations do not appear to be a primary event responsible for neoplastic growth in parathyroid tissue.

W-7, a calmodulin antagonist, primes the stimulation of human neutrophil respiratory burst by formyl peptides and platelet-activating factor.

Low concentrations of the calmodulin antagonist W-7 (1-10 microM) enhanced the respiratory burst (RB) of human polymorphonuclear leukocytes (PMN) stimulated by N-formyl-methionyl-leucyl-phenylalanine, whereas high drug concentrations (above 20 microM) depressed it. The maximal increase obtained with 5-10 microM W-7 affected both initial rate (50%) and total superoxide anion production (150%). W-7 also primed both parameters of the RB mediated by platelet-activating factor, although higher drug concentrations were required (15-50 microM). By contrast, W-7 depressed the RB induced by the calcium ionophore A23187 and by a protein kinase C activator, phorbol myristate acetate, with an IC50 of approximately 20 and 8 microM, respectively. These data show the enhancing effect of W-7 on chemoattractant-mediated RB and suggest that RB priming may involve calmodulin-dependent regulation of chemoattractant-mediated early signalling events.

Immunochemical identification and translocation of protein kinase C zeta in human neutrophils.

Western blots of human polymorphonuclear leukocyte (PMN) extracts were immunostained with antibodies specific for various protein kinase C (PKC) isoforms. Two bands corresponding to PKC type zeta with apparent molecular masses of 81 kDa and 76 kDa were identified in the cytosolic fraction of resting cells, in addition to PKC types alpha and beta. PKC zeta was apparently abundant, like PKC beta, whereas PKC delta, -epsilon, and -gamma were not detectable. Following short stimulation (5 min) of PMN with phorbol-12-myristate-13-acetate (1 microgram/ml), physical translocation of PKC zeta from the cytosol to the plasma membrane fraction occurred, although this isoform does not bind phorbol esters. These data show that, in addition to the two calcium-dependent isoenzymes alpha and beta, human PMN express a calcium-independent isoenzyme zeta which translocates in stimulated cells, suggesting a role in the regulation of antibacterial activities.