CD44 and hyaluronic acid regulate in vivo iNOS expression and metalloproteinase activity in murine air-pouch inflammation

OBJECTIVE

To evaluate the effects of anti-CD44 IM7.8.1 antibody, HMW-HA and LMW-HA on leukocyte migration and adhesion, and the induction of proinflammatory mediators, in mouse air-pouch inflammation induced by zymosan.

METHODS

Leukocytes were obtained from zymosan-air pouches after the intra-pouch injection of anti-CD44 IM7.8.1, isotype control, HMW-HA, LMW-HA or PBS. TNF-alpha, IL-1beta and iNOS mRNA were estimated in leukocytes by semi-quantitative RT-PCR. Matrix metalloproteinases (MMPs) from exudates were evaluated by zymography and Western Blot. Adhesion and migration of leukocytes were evaluated in HA-coated plates and Boyden chambers respectively.

RESULTS

IM7.8.1 decreased iNOS mRNA levels and the activity of both MMP-9 and MMP-2 eight h after injection into zymosan air pouch while IM7.8.1, HMW-HA and LMW-HA had no effect on IL1-beta or TNF-alpha mRNA levels. Leukocytes from air pouch adhered to and migrated in vitro against both HMW-HA and LMW-HA. LMW-HA increased the number of leukocytes in the air pouch and iNOS mRNA levels as compared to PBS injection. In contrast, HMW-HA decreased leukocyte count and reduced iNOS mRNA levels. Paradoxically, the activity of both MMP-9 and MMP-2 was increased by HMW-HA and decreased by LMW-HA.

CONCLUSIONS

Both CD44 and HA can modulate leukocyte migration and induction of proinflammatory mediators in mouse zymosan air pouch inflammation. IM7.8.1 had consistent anti-inflammatory effects, reducing iNOS, MMP-9 and MMP-2. HMW-HA and LMW-HA were able to modulate both the induction of proinflammatory mediators and leukocyte count in the air pouch.

Lymphoplasmacytic hyperplasia (possibly pre-PTLD) has varied expression and appearance in intestinal transplant recipients receiving Campath immunosuppression

Posttransplant lymphoproliferative disorders (PTLD) are a frequent complication in bowel transplant recipients. Histological changes in PTLD range from expansile lymphoplasmacytic (LP) hyperplasia to frank lymphoma. Small bowel allograft biopsies obtained in the first 250 days posttransplant were retrospectively graded after patients had received induction immunosuppression with either anti-CD52 (Campath) or anti-CD25 (Zenapax) monoclonal antibodies. The biopsies were analyzed with respect to the onset intensity of lymphoplasmacytic infiltrates and presence of in situ EBV hybridization (EBER) positivity. We observed that lymphoplasmacytic infiltrates were a frequent change in all bowel transplant patients over the examined period. Campath-treated patients developed earlier LP infiltrates of mild to moderate intensity between day 1 and 100 posttransplant, thereafter decreasing to mild. No EBER positivity was detected in this group. Zenapax-treated patients presented with LP infiltrates later of mild to moderate intensity through day 100 posttransplant. However, more persistent and intense LP infiltrates was observed after day 101 in this group, including a case of lymphoma and two cases of EBER positivity. We conclude that Campath immunosuppression results in an earlier appearance of LP lesions that are generally less intense than those evident with Zenapax. We attribute these findings to the more profound immunodeficiency and cell targeting following Campath treatment.

Households contaminated by environmental tobacco smoke: sources of infant exposures

OBJECTIVES

To examine (1) whether dust and surfaces in households of smokers are contaminated with environmental tobacco smoke (ETS); (2) whether smoking parents can protect their infants by smoking outside and away from the infant; and (3) whether contaminated dust, surfaces, and air contribute to ETS exposure in infants.

DESIGN

Quasi-experiment comparing three types of households with infants: (1) non-smokers who believe they have protected their children from ETS; (2) smokers who believe they have protected their children from ETS; (3) smokers who expose their children to ETS.

SETTING

Homes of smokers and non-smokers.

PARTICIPANTS

Smoking and non-smoking mothers and their infants < or = 1 year.

MAIN OUTCOME MEASURES

ETS contamination as measured by nicotine in household dust, indoor air, and household surfaces. ETS exposure as measured by cotinine levels in infant urine.

RESULTS

ETS contamination and ETS exposure were 5-7 times higher in households of smokers trying to protect their infants by smoking outdoors than in households of non-smokers. ETS contamination and exposure were 3-8 times higher in households of smokers who exposed their infants to ETS by smoking indoors than in households of smokers trying to protect their children by smoking outdoors.

CONCLUSIONS

Dust and surfaces in homes of smokers are contaminated with ETS. Infants of smokers are at risk of ETS exposure in their homes through dust, surfaces, and air. Smoking outside the home and away from the infant reduces but does not completely protect a smoker's home from ETS contamination and a smoker's infant from ETS exposure.

Expanded huntingtin activates the c-Jun terminal kinase/c-Jun pathway prior to aggregate formation in striatal neurons in culture

Huntington's disease (HD) is an autosomal neurodegenerative disorder, caused by expansion of a glutamine repeat in the Huntingtin protein. Pathogenesis in HD includes the cytoplasmic cleavage of Huntingtin and release of an amino-terminal fragment capable of nuclear localization, where expanded-Huntingtin (Exp-Htt) might lead to aberrant transcriptional regulation, neuronal dysfunction and degeneration. Recent evidence, from hippocampal cell lines, also implicates altered interaction of Exp-Htt with components of the c-Jun N-terminal kinase (JNK) cascade. However, there is yet no proven implication of the JNK/c-Jun module in degeneration of striatal neurons, the more vulnerable cell population, in HD. In the present study, we used primary striatal neurons in culture to analyze c-Jun activation by Exp-Htt. Green fluorescent protein (GFP)-tagged exon 1 of human Huntingtin either in its normal (25Q, normal-Htt) or expanded (103Q, Exp-Htt) version was transiently transfected in these cells. We first set out, in our conditions, the time course of striatal degeneration produced by Exp-Htt, and found it occurred rapidly. At 48 h post-transfection, 60% of striatal neurons expressing Exp-Htt had apoptotic characteristics including DNA fragmentation and neuritic retraction. Most of these neurons also showed nuclear aggregates of GFP-Exp Htt. Kinetics of c-Jun activation were tested in transfected cells using immunocytochemical detection of phospho-c-Jun. We found a significant activation and induction of c-Jun in Exp-Htt but not normal-Htt-transfected neurons. Of interest, these events occurred prior to nuclear translocation of Exp-Htt. Finally, overexpression of a dominant negative version of c-Jun, as well as pharmacological inhibition of JNK strongly protected against DNA fragmentation and neuritic retraction induced by Exp-Htt. Thus our data suggest that c-Jun activation and induction, is an early event in the pathogenesis of HD, occurring prior to formation of nuclear aggregates of Exp-Htt.

Evolutionary conserved chromosomal segments in the human karyotype are bounded by unstable chromosome bands

In this paper an ancestral karyotype for primates, defining for the first time the ancestral chromosome morphology and the banding patterns, is proposed, and the ancestral syntenic chromosomal segments are identified in the human karyotype. The chromosomal bands that are boundaries of ancestral segments are identified. We have analyzed from data published in the literature 35 different primate species from 19 genera, using the order Scandentia, as well as other published mammalian species as out-groups, and propose an ancestral chromosome number of 2n = 54 for primates, which includes the following chromosomal forms: 1(a+c(1)), 1(b+c(2)), 2a, 2b, 3/21, 4, 5, 6, 7a, 7b, 8, 9, 10a, 10b, 11, 12a/22a, 12b/22b, 13, 14/15, 16a, 16b, 17, 18, 19a, 19b, 20 and X and Y. From this analysis, we have been able to point out the human chromosome bands more "prone" to breakage during the evolutionary pathways and/or pathology processes. We have observed that 89.09% of the human chromosome bands, which are boundaries for ancestral chromosome segments, contain common fragile sites and/or intrachromosomal telomeric-like sequences. A more in depth analysis of twelve different human chromosomes has allowed us to determine that 62.16% of the chromosomal bands implicated in inversions and 100% involved in fusions/fissions correspond to fragile sites, intrachromosomal telomeric-like sequences and/or bands significantly affected by X irradiation. In addition, 73% of the bands affected in pathological processes are co-localized in bands where fragile sites, intrachromosomal telomeric-like sequences, bands significantly affected by X irradiation and/or evolutionary chromosomal bands have been described. Our data also support the hypothesis that chromosomal breakages detected in pathological processes are not randomly distributed along the chromosomes, but rather concentrate in those important evolutionary chromosome bands which correspond to fragile sites and/or intrachromosomal telomeric-like sequences.

Erectile dysfunction in heart disease patients

Atherosclerosis is a general health problem that not only affects the coronary arteries but also (in men) the penile arteries, thus contributing to organic causes of erectile dysfunction (ED) in heart disease patients. These organic causes are intertwined with psychological and pharmacological causes because medication prescribed for heart disease patients may also cause ED. The incidence of ED after myocardial infarction ranges from 38 to 78%. As sexual intercourse involves physical exertion, the medical history, ventricular function determined through echocardiography, and stress testing are used to classify patients into various groups where coital activity represents a greater or lesser cardiovascular risk. The energy requirements for intercourse are not high, ranging from 3.7 metabolic equivalents (METs) of energy expenditure at resting state during the preorgasmic phase to 5 METs during orgasm. The Bruce protocol for exercise stress testing is a six-stage protocol with changes in the slope and speed of the treadmill. As a general rule, a patient who completes the first two stages of the Bruce protocol has a functional capacity greater than 7 METs, which is considered sufficient for sexual intercourse. The physician or cardiologist concerned should institute first-line treatment with oral drugs according to the indications listed below. If sexual activity is not contraindicated, the treatment of choice for ED in heart disease patients is oral therapy with sildenafil, except in those cases in which its use is contraindicated. Specific recommendations are discussed.

Early neurologic deterioration in intracerebral hemorrhage: Predictors and associated factors

OBJECTIVE

To identify potential predictors of and factors associated with early neurologic deterioration (END) in primary intracerebral hemorrhage (ICH).

METHODS

Two hundred sixty-six patients with spontaneous supratentorial ICH admitted within 12 hours of stroke onset were investigated in a multicenter, prospective study. Sixty-one clinical, biochemical, and neuroimaging variables were registered on admission, and 37 clinical and neuroimaging variables were registered at 48 hours. The volumes of the ICH and peripheral edema on admission and at 48 hours were measured on CT scan. Stroke severity and functional outcome were evaluated with the Canadian Stroke Scale (CSS) and modified Rankin Scale. END was diagnosed when the CSS score decreased > or =1 points between admission and 48 hours. With use of logistic regression analyses, baseline variables that predicted END and factors measured after the early acute phase and associated with END were investigated.

RESULTS

END occurred in 61 (22.9%) patients. Body temperature of >37.5 degrees C (odds ratio [OR] 24.5; 95% CI 4.8 to 125), neutrophil count (by 1,000-unit increase; OR 2.1; 95% CI 1.6 to 2.6), and serum fibrinogen levels of >523 mg/dL (OR 5.6; 95% CI 1.9 to 16.2) on admission were independent predictors of END. Among the factors recorded at 48 hours, early ICH growth (OR 4.3; 95% CI 1.3 to 14.5), intraventricular bleeding (OR 2.6; 95% CI 1.4 to 5.0), and highest systolic blood pressure (by 10-unit increase; OR 1.17; 95% CI 1.02 to 1.32) were associated with END in multivariate analyses.

CONCLUSIONS

Clinical and biologic markers of the inflammatory reaction on admission are predictors of subsequent END, whereas early ICH growth, intraventricular bleeding, and high systolic blood pressure within 48 hours are factors associated with END in patients with spontaneous ICH.

Pharmacology of novel heteroaromatic polycycle antibacterials

Heteroaromatic polycycle (HARP) compounds are a novel class of small (M(w), 600 to 650) DNA-binding antibacterials. HARP compounds exhibit a novel mechanism of action by preferentially binding to AT-rich sites commonly found in bacterial promoters and replication origins. Noncovalent binding in the minor groove of DNA results in inhibition of DNA replication and DNA-dependent RNA transcription and subsequent bacterial growth. HARP compounds have previously been shown to have potent in vitro activities against a broad spectrum of gram-positive organisms. The present report describes the extensive profiling of the in vitro and in vivo pharmacology of HARP antibacterials. The efficacies of representative compounds (GSQ-2287, GSQ-10547, and GSQ-11203), which exhibited good MIC activity, were tested in murine lethal peritonitis and neutropenic thigh infection models following intravenous (i.v.) administration. All compounds were efficacious in vivo, with potencies generally correlating with MICs. GSQ-10547 was the most potent compound in vitro and in vivo, with a 50% effective dose in the murine lethal peritonitis model of 7 mg/kg of body weight against methicillin-sensitive Staphylococcus aureus (MSSA) and 13 mg/kg against methicillin-resistant S. aureus (MRSA). In the neutropenic mouse thigh infection model, GSQ-11203 reduced the bacterial load (MRSA and MSSA) 2 log units following administration of a 25-mg/kg i.v. dose. In a murine lung infection model, treatment with GSQ-10547 at a dose of 50 mg/kg resulted in 100% survival. In addition to determination of efficacy in animals, the pharmacokinetic and tissue disposition profiles in animals following administration of an i.v. dose were determined. The compounds were advanced into broad safety screening studies, including screening for safety pharmacology, genotoxicity, and rodent toxicity. The results support further development of this novel class of antibiotics.

Female-specific features of recombinational double-stranded DNA repair in relation to synapsis and telomere dynamics in human oocytes

Chromosome segregation errors are a significant cause of aneuploidy among human neonates and often result from errors in female meiosis that occur during fetal life. For the latter reason, little is known about chromosome dynamics during female prophase I. Here, we analyzed chromosome reorganization, and centromere and telomere dynamics in meiosis in the human female by immunofluorescent staining of the SYCP3 and SYCP1 synaptonemal complex proteins and the course of recombinational DNA repair by IF of phospho-histone H2A.X (gamma-H2AX), RPA and MLH1 recombination proteins. We found that SYCP3, but not SYCP1, aggregates appear in the preleptotene nucleus and some persist up to pachytene. Telomere clustering (bouquet stage) in oocytes lasted from late-leptotene to early pachytene-significantly longer than in the male. Leptotene and zygotene oocytes and spermatocytes showed strong gamma-H2AX labeling, while gamma-H2AX patches, which colocalized with RPA, were present on SYCP1-tagged pachytene SCs. This was rarely seen in the male and may suggest that synapsis installs faster with respect to progression of recombinational double-strand break repair or that the latter is slower in the female. It is speculated that the presence of gamma-H2AX into pachytene highlights female-specific peculiarities of recombination, chromosome behavior and checkpoint control that may contribute to female susceptibility for aneuploidy.

Households contaminated by environmental tobacco smoke: sources of infant exposures

OBJECTIVES

To examine (1) whether dust and surfaces in households of smokers are contaminated with environmental tobacco smoke (ETS); (2) whether smoking parents can protect their infants by smoking outside and away from the infant; and (3) whether contaminated dust, surfaces, and air contribute to ETS exposure in infants.

DESIGN

Quasi-experiment comparing three types of households with infants: (1) non-smokers who believe they have protected their children from ETS; (2) smokers who believe they have protected their children from ETS; (3) smokers who expose their children to ETS.

SETTING

Homes of smokers and non-smokers.

PARTICIPANTS

Smoking and non-smoking mothers and their infants < or = 1 year.

MAIN OUTCOME MEASURES

ETS contamination as measured by nicotine in household dust, indoor air, and household surfaces. ETS exposure as measured by cotinine levels in infant urine.

RESULTS

ETS contamination and ETS exposure were 5-7 times higher in households of smokers trying to protect their infants by smoking outdoors than in households of non-smokers. ETS contamination and exposure were 3-8 times higher in households of smokers who exposed their infants to ETS by smoking indoors than in households of smokers trying to protect their children by smoking outdoors.

CONCLUSIONS

Dust and surfaces in homes of smokers are contaminated with ETS. Infants of smokers are at risk of ETS exposure in their homes through dust, surfaces, and air. Smoking outside the home and away from the infant reduces but does not completely protect a smoker's home from ETS contamination and a smoker's infant from ETS exposure.

Immunoenzymatic and morphological detection of epithelial cell apoptotic stages in gastrointestinal allografts from multivisceral transplant patients

Acute allograft rejection (AR) is a major contributor to morbidity and mortality among patients who undergo multivisceral transplantation. Critical to the assessment of AR is detection of apoptosis in the glandular epithelium of the gastrointestinal allograft. We utilized the TUNEL stain (TdT-mediated biotin 16-dUTP nick-end labeling) to test whether this method improved detection of apoptosis compared to standard slide evaluation. TUNEL and H&E stains were performed on paraffin-embedded tissue sections to estimate the number of apoptotic bodies per 10 high power fields, as determined by independent pathologists in blinded fashion. Both methodologies showed similar numbers and distributions of apoptotic foci present among the epithelial cells. There was a correlation between the number of apoptosis and the grade of rejection (P <.001). This is the first use of the TUNEL stain in gastrointestinal allograft biopsies to our knowledge. The similarity in pattern and sensitivity of TUNEL with standard morphology confirms that biopsy assessment with routine H&E staining allows an accurate appraisal of epithelial cell apoptosis. Therefore, current staining protocols for endoscopically derived mucosal biopsies of gastrointestinal allografts are sufficiently accurate to enumerate the critical feature of epithelial apoptosis as a determinant of the grade of acute rejection.

Campath-1H immunosuppressive therapy reduces incidence and intensity of acute rejection in intestinal and multivisceral transplantation

Campath-1H, an anti-CD52 antibody, is being used at our institution as immunosuppression in multivisceral and intestinal transplantation. We reviewed the pathologic findings of 1696 small bowel allograft biopsies obtained in the first 250 days posttransplant from 78 patients who underwent isolated intestinal or multivisceral transplantation and received induction immunosuppression with Campath (n = 30) or Zenapax (n = 57). We found an overall reduced incidence of acute cellular rejection (ACR) in patients receiving Campath (19.1%) compared with those on Zenapax (32.8%). The majority of Campath patients showed no rejection or was indeterminate for rejection over the period of measurement. The frequencies of mild and moderate ACR were approximately twice and three times more common, respectively, in Zenapax-treated patients. The mean grade of ACR in Campath patients compared with Zenapax patients was significantly lower (P <.01) during the first 6 weeks posttransplant. Thereafter, the grade of rejection in both patient groups showed fluctuation, with Zenapax patients sometimes having lower values (eg, at 2 to 4 months) than Campath patients. Patient and graft survival was not significantly different between the two groups. These data suggest that the incidence of ACR is significantly reduced with Campath during the first 2 months posttransplant, when compared with Zenapax. However, the incidence and intensity of ACR following this initial time period shows vacillation with both types of immunosuppression.

Oral anti-pneumococcal activity and pharmacokinetic profiling of a novel peptide deformylase inhibitor

OBJECTIVE

BB-81384, a novel peptide deformylase (PDF) inhibitor, was characterized in terms of enzyme inhibition profile, antibacterial activity, rodent pharmacokinetics and oral efficacy in murine infection models.

METHODS

MICs were determined by standard NCCLS broth microdilution. Selectivity of metalloenzyme inhibition was determined with a limited panel of enzymes via standard biochemical assays. Profiling of the pharmacokinetics and select tissue disposition in mice was determined and compared with that of the macrolide, azithromycin. In vivo murine efficacy studies using Streptococcus pneumoniae were conducted using a peritonitis model, as well as lung and thigh burden models of infection.

RESULTS

BB-81384 selectively inhibited PDF with an IC(50) approximately 10 nM and with MICs < 0.5 mg/L against most S. pneumoniae pathogens. Pharmacokinetic analysis revealed good oral bioavailability and moderate clearance and volume of distribution. BB-81384 partitioning to lung tissue was similar in terms of magnitude and kinetics to that of the plasma compartment. Single-administration oral efficacy in a mouse peritonitis model was evident with an ED(50) of 30 mg/kg. BB-81384 reduced the bacterial load by approximately 5 and 3 log units in organ-burden models of lung and thigh infection, respectively.

CONCLUSION

BB-81384, a novel PDF inhibitor with good activity against S. pneumoniae in vitro, was the first compound of this class to be profiled for oral pharmacokinetics and tissue disposition and to demonstrate oral anti-pneumococcal efficacy in mice.

Beneficial effects of HLA class II incompatibility in living donor liver transplantation

OBJECTIVE

To analyze the impact of HLA matching in both patient and graft evolution after LDLT.

MATERIAL AND METHODS

Twenty recipients underwent LDLT with follow-up of 3 to 30 months. HLA typing was performed on all donor-recipient pairs; class I antigens were typed using serological methods and class II loci (DRB1 and DQB1) using low-resolution molecular typing. Recipient sera were cross-matched with donor lymphocytes. Antigen mismatches were analyzed for each locus individually, for each class as a whole and for HLA class I immunogenic triplets according to HLA Matchmaker software.

RESULTS

Eighteen of 20 donor-recipient pairs were HLA haploidentical. All but one of the recipients had a negative cross-match before transplantation. While there was not a statistically significant correlation between HLA class I mismatches and the incidence of acute rejection episodes, HLA class II matching in DRB1 and DQB1 loci appeared to be associated with a higher incidence of acute rejection episodes after LDLT. Both host-versus-graft (HvG) and graft-versus-host (GvH) HLA class II compatibilities correlated with rejection episodes, especially for the GvH direction.

CONCLUSIONS

HLA class II matching for DRB1 and DQB1 loci appears to be associated with a higher incidence of acute rejection episodes after LDLT. In this study, mismatches in class I HLA antigens are not related to an higher incidence of acute rejection episodes nor other complications after LDLT. Further studies are needed to unveil the role of HLA matching in LDLT.

How to target estrogen receptor-negative breast cancer?

Estrogen receptor (ER)-positive breast cancers generally have a better prognosis and are often responsive to anti-estrogen therapy, which is the first example of a successful therapy targeted on a specific protein, the ER. Unfortunately ER-negative breast cancers are more aggressive and unresponsive to anti-estrogens. Other targeted therapies are thus urgently needed, based on breast cancer oncogene inhibition or suppressor gene activation as far as molecular studies have demonstrated the alteration of expression, or structure of these genes in human breast cancer. Using the MDA-MB.231 human breast cancer cell line as a model of ER-negative breast cancers, we are investigating two of these approaches in our laboratory. Our first approach was to transfect the ER or various ER-deleted variants into an ER-negative cell line in an attempt to recover anti-estrogen responsiveness. The unliganded receptor, and surprisingly estradiol, were both found to inhibit tumor growth and invasiveness in vitro and in vivo. The mechanisms of these inhibitions in ER-negative cancer cells are being studied, in an attempt to target the ER sequence responsible for such inhibition in these cancer cells. Another strategy is trying to inhibit the activity or expression of an oncogene specifically overexpressed in most breast cancers. This approach was recently shown by others to be efficient in breast cancer therapy with HER2-Neu oncogene amplification using Herceptin. Without excluding other molecular putative targets, we have focused our research on cathepsin D as a potential target, since it is often overexpressed in aggressive human breast cancers, including ER-negative tumors, and rarely associated with HER2-Neu amplification. Our first results obtained in vitro on cell lines and in vivo in tumor xenografts in nude mice, illustrate that the mode of action of cathepsin D in breast cancer is useful to guide the development of these therapies. In the past 20 years we have learned that the action of cathepsin D is complex and involves both intracellular and extracellular activities due to its proteolytic activity and to interactions with membrane components without catalytic activity. Each of these mechanisms could be potentially inhibited in an attempt to prevent tumor growth. Breast cancer is a very heterogeneous and multigenic disease and different targeted therapies adapted to each category of breast cancer are therefore required. Validated assays in the primary tumor of molecular markers such as ER, HER2-Neu and cathepsin D should help to predict which targeted therapy should be applied to cure breast cancer patients.

Factors associated with time to sputum smear conversion in active pulmonary tuberculosis

OBJECTIVE

To ascertain the factors affecting the time between the initiation of treatment and obtaining three negative sputum smears.

DESIGN

In a study of 109 patients with pulmonary tuberculosis, the main variable was the period during which the patients had sputum smears once treatment was initiated. Multivariate analysis (multiple linear regression) was performed to document those variables independently associated with time to conversion.

RESULTS

The patients had positive smears for a mean of 28.63 days. The most frequent radiographic pattern was cavitary disease (36.7%). HIV co-infection was present in 38.5% of the patients. HIV-infected patients showed a cavitation pattern in only 9.6% vs 52.2% of patients without HIV infection (P < 0.001). The variables that showed a statistically significant and independent relationship with the time to sputum smear conversion were pulmonary radiographic pattern, age and erythrocyte sedimentation rate (ESR).

CONCLUSIONS

ESR, age and the presence of cavitary disease seem to be factors associated with a longer time to sputum smear conversion in patients with active pulmonary tuberculosis. However, HIV co-infection is associated with a shorter time to sputum conversion. A key factor is therefore the presence or not of cavitation, independently of HIV infection.