Characterization of the nucleotide-binding capacity and the ATPase activity of the PIP3-binding protein JFC1

In this work, we demonstrate that the phosphatidylinositol 3,4,5-trisphosphate-binding protein JFC1 is an ATP-binding protein with magnesium-dependent ATPase activity. We show that JFC1 specifically binds to the ATP analog 8-azido-[alpha-(32)P]ATP. The affinity of JFC1 for [alpha-(32)P]ATP was 10x greater than its affinity for [alpha-(32)P]ADP; the protein did not appear to bind to [alpha-(32)P]GTP. JFC1 hydrolyzed [alpha-(32)P]ATP in a Mg(2+)-dependent manner. JFC1, which also hydrolyzed dATP, has a relatively high affinity for ATP, with a K(M) value of 58 microM, and a k(cat) value of 2.27 per min. The predicted amino acid sequence of JFC1 denotes a putative nucleotide-binding site similar to those in the GHKL ATPase/kinase superfamily. However, a truncation of JFC1 that contains boxes G2 and G3 but not boxes N and G1 of the Bergerat-binding site showed residual ATPase activity. Secondly, the antitumor ATP-mimetic agent geldanamycin, which inhibits the ATPase activity of Hsp-90, did not affect JFC1 ATPase. Therefore, the characteristics of the ATP-binding site of JFC1 are unique. Phosphatidylinositol 3,4,5-trisphosphate, a high-affinity ligand of JFC1 did not affect its ATPase kinetics parameters, suggesting that the phosphoinositide have a different role in JFC1 function.

Through the haze of cigarettes: teenage girls' stories about cigarette addiction

Narrative inquiry was used to explore the meaning of nicotine addiction among teenage girls, age 14 to 17 years, who had recent experience with smoking. The following three narratives emerged: invincibility, giving in, and unanticipated addiction. Those who told a story of invincibility depicted how they were in control of their smoking and not addicted. Participants who gave accounts of giving in to smoking described yielding to external forces. In the narrative of unanticipated addiction, participants recounted their surprise at realizing that they were addicted. Two subnarratives, needing to quit and repeating history, were also uncovered. The study findings reveal the importance of semantics and identity issues as teenage girls talked about nicotine addiction. Listening to their stories is paramount in continued efforts in the reduction of tobacco consumption.

Increased replication of HIV-1 at sites of Mycobacterium tuberculosis infection: potential mechanisms of viral activation

Tuberculosis (TB) enhances HIV-1 replication and the progression to AIDS in dually infected patients. We employed pleural TB as a model to understand the interaction of the host with HIV-1 during active TB, at sites of Mycobacterium tuberculosis (MTB) infection. HIV-1 replication was enhanced both in the cellular (pleural compared with blood mononuclear cells) and acellular (pleural fluid compared with plasma) compartments of the pleural space. Several potential mechanisms for expansion of HIV-1 in situ were found, including augmentation in expression of tumor necrosis factor (TNF)-alpha and the HIV-1 noninhibitory beta-chemokine (MCP-1), low presence of HIV-1 inhibitory beta-chemokines (MIP-1 alpha, MIP-1 beta, and RANTES [regulated on activation, normal T expressed and secreted]), and upregulation in expression of the HIV-1 coreceptor, CCR5, by pleural fluid mononuclear cells. Thus, at sites of MTB infection, conditions are propitious both for transcriptional activation of HIV-1 in latently infected mononuclear cells, and facilitation of viral infection of newly recruited cells. These mechanisms may contribute to enhanced viral burden and dissemination during TB infection.

Plasmin-mediated fibroblast growth factor-2 mobilisation supports smooth muscle cell proliferation in human saphenous vein

The focus of this study was identification of the contribution of the plasminogen activator-plasmin system to smooth muscle cell proliferation and migration in human saphenous vein. Segments of human saphenous vein were grown in organ culture for up to 14 days. Smooth muscle cell proliferation and migration were measured by incubating vein segments in bromodeoxyuridine, and smooth muscle cell death was detected by in situ end-labelling. Tissue-type (tPA) and urokinase-type (uPA) plasminogen activator enzymic activities were detectable in cultured saphenous vein segments, and were concentrated in focal zones. Inhibition of plasmin activity with alpha-N-acetyl-L-lysine methyl ester (NALME) or of uPA activity with a neutralising antibody caused significant decreases in smooth muscle cell proliferation in the media and the intima, but no significant changes in smooth muscle cell migration. Intimal thickness was also significantly decreased. Incubation with plasminogen or plasmin caused fibroblast growth factor-2 (FGF2) to be released into the medium. Addition of FGF2 to segments cultured with NALME reversed the inhibition of smooth muscle cell proliferation, and blocking the activity of FGF2 with a neutralising antibody caused a significant decrease in medial smooth muscle cell proliferation. These data suggest that plasmin mobilises FGF2 bound to the extracellular matrix of human saphenous vein, so that it can support smooth muscle cell proliferation and intimal thickening.

Retinal photoreceptors and visual pigments in Boa constrictor imperator

The photoreceptors of Boa constrictor, a boid snake of the subfamily Boinae, were examined with scanning electron microscopy and microspectrophotometry. The retina of B. constrictor is duplex but highly dominated by rods, cones comprising 11% of the photoreceptor population. The rather tightly packed rods have relatively long outer segments with proximal ends that are somewhat tapered. There are two morphologically distinct, single cones. The most common cone by far has a large inner segment and a relatively stout outer segment. The second cone, seen only infrequently, has a substantially smaller inner segment and a finer outer segment. The visual pigments of B. constrictor are virtually identical to those of the pythonine boid, Python regius. Three different visual pigments are present, all based on vitamin A(1.) The visual pigment of the rods has a wavelength of peak absorbance (lambda(max)) at 495 +/- 2 nm. The visual pigment of the more common, large cone has a lambda(max) at 549 +/- 1 nm. The small, rare cone contains a visual pigment with lambda(max) at 357 +/- 2 nm, providing the snake with sensitivity in the ultraviolet. We suggest that B. constrictor might employ UV sensitivity to locate conspecifics and/or to improve hunting efficiency. The data indicate that wavelength discrimination above 430 nm would not be possible without some input from the rods.

The desi ways: traditional health practices of South Asian women in Canada

Although many South Asian immigrants have made their homes in Canada, little research has examined health behaviors in this population and fewer studies have examined the use of traditional health practices. As part of a larger study on health-seeking patterns of South Asian women living in Western Canada, an analysis was done on the use of traditional health practices. Using critical ethnographic methods, data were collected through face-to-face individual interviews (n = 50), focus group discussions (n = 12), and community meetings with a cross section of women in the South Asian community. Interviews were conducted in the language of each participant's choice. Thematic analysis was done on the transcribed interviews. Women's descriptions of traditional health practices varied and consisted of home remedies, dietary regimens, prayers, rituals, and consultation with hakims, veds, babajis, pundits, homeopaths, and jyotshis. Choosing to use traditional health practices was influenced by family members, the nature and severity of problems, beliefs and prior experiences, and the feasibility of using these practices. Traditional health practices were used on a daily or episodic basis. Women rarely used traditional health practices exclusively. Traditional health practices were used for small problems or when conventional medicines did not work. For women to meet their health needs, health care providers must be culturally sensitive and respect women's choices to use traditional health practices.

Intraperitoneal blood exacerbates the remote inflammatory response to murine peritonitis

BACKGROUND

This study investigated the effects of intra-abdominal blood on the systemic response to peritonitis using a murine model of hemorrhage, peritonitis, and multiple organ dysfunction syndrome.

METHODS

The model used male ICR mice subjected to hemorrhage and intraperitoneal zymosan. Half of the mice received intraperitoneal blood. Outcome measures included lung myeloperoxidase, lung edema, lung injury score, and plasma and lung tissue chemokine production.

RESULTS

Peritoneal blood (in association with peritoneal inflammation) increased lung neutrophil sequestration (myeloperoxidase) (2.56 +/- 1.42 vs. 1.45 +/- 0.49 U/left lung, p = 0.04) and lung weight (0.11 +/- 0.04 vs. 0.07 +/- 0.02 g/left lung, p = 0.02), and was associated with significantly higher chemokine levels in plasma (KC and MCP-1) and lung tissue (KC, MIP-2, and MCP-1). Both plasma and lung tissue neutrophil chemoattractants KC and MIP-2 were significantly linearly correlated with myeloperoxidase (p < 0.009), and lung tissue KC (a neutrophil chemokine) and MCP-1 and MIP-1alpha (mononuclear cell chemokines) correlated with lung injury score (p < 0.003).

CONCLUSION

Although blood alone in the peritoneal cavity was well tolerated, in conjunction with inflammation, it was synergistic in amplifying the systemic inflammatory response. The amplified lung injury in this model was associated with significant increases in circulating and lung tissue chemokine concentrations.

Evaluation of suspected tuberculous pleurisy: clinical and diagnostic findings in HIV-1-positive and HIV-negative adults in Uganda

SETTING

National Tuberculosis Treatment Centre, Mulago Hospital, Kampala, Uganda.

OBJECTIVES

To compare clinical and radiographic presentation, and diagnostic methods, in adults with tuberculous pleurisy who are negative and positive for the human immunodeficiency virus (HIV).

DESIGN

Adults with suspected pleural tuberculosis were screened by clinical examination, thoracocentesis and closed pleural biopsy. Biopsy material was cultured on Middlebrook 7H-10 solid medium and in BACTEC 12B radiometric vials. Pleural fluid was cultured using Löwenstein-Jensen slants, BACTEC and Kirchner liquid medium.

RESULTS

Of 156 individuals enrolled, 142 had tuberculosis, of whom 80% were HIV-positive. Among those with tuberculosis, HIV-positive patients bad a more severe and longer illness. The size of effusions was similar in HIV-positive and HIV-negative patients. A higher proportion of HIV-positive patients had parenchymal infiltrates but this difference was not statistically significant. Pleural fluid lymphocytosis was present in all HIV-negative and 97% of the HIV-positive patients. HIV-positive patients had lower pleural fluid lymphocyte counts. Pleural fluid cultures were more often positive in HIV-positive patients. BACTEC and Kirchner liquid media gave higher yields than solid media.

CONCLUSION

HIV-positive patients with tuberculous pleurisy had a more severe illness than HIV-negative patients. Mycobacterial cultures from HIV-positive patients were more often positive, suggesting more mycobacterial extension from the lungs into the pleural space. Liquid culture media were superior to solid media with regard to diagnostic yield and time until diagnosis.

Cyclophosphamide, doxorubicin, vincristine, prednisone, and etoposide (CHOPE) for advanced-stage Hodgkin's disease: CALGB 8856

Successful treatment of advanced-stage Hodgkin's disease (HD) may critically depend on dose intensity. Because mechlorethamine, Oncovin, procarbazine, and prednisone (MOPP), and Adriamycin, bleomycin, vinblastine, and dacarbazine (ABVD) are not suitable for major dose escalation, we evaluated the activity and toxicity of combined cyclophosphamide, doxorubicin, vincristine, prednisone, and etoposide (CHOPE) in advanced HD, here used at conventional dose intensity, as a preparatory study prior to using this regimen at higher dose intensity. Ninety-two patients were treated with CHOPE (cyclophosphamide, 750 mg/m2, day 1; doxorubicin, 50 mg/m2, day 1; vincristine, 1.4 mg/m2, days 1 and 8; prednisone, 100 mg/day, days 1-5; and etoposide, 80 mg/m2, days 1, 2, and 3) every 21 days. All had advanced HD with no prior chemotherapy with 46% stage IV, 63% with B symptoms, and 57% with bulky disease (> 5 cm). Radiation and growth factor support were not permitted. Full-dose vincristine (not capped at maximum 2 mg/dose) was used in the first 33 patients. An initial cohort of 41 patients was treated with four cycles of CHOPE to evaluate safety and efficacy followed by four cycles of ABVD. A second cohort of 51 patients was treated with 6-8 cycles of CHOPE alone. Toxicity was generally acceptable and primarily hematologic, with neutrophils < 500 in 63% of cohort I and 90% of cohort II, and platelets < 25,000 in 7% of cohort I and 8% of cohort II. The long-term neurotoxicity of full-dose, high-intensity vincristine was acceptable and largely reversible. In cohort I, 92% of patients achieved a complete response (CR) or partial response (PR) with four cycles of CHOPE and 85% were in CR after four additional cycles of ABVD. In cohort II, 77% achieved a CR with 6-8 cycles of CHOPE alone. FFS was 76% in cohort I and 59% in cohort II, with a median follow-up of 8.2 and 5.7 years, respectively. CHOPE, at conventional dose intensity as used here, is an effective first-line regimen for the treatment of advanced-stage HD and may warrant evaluation using higher doses of cyclophosphamide and etoposide with granulocyte colony stimulating factor (G-CSF) support.

Dose-escalated cyclophosphamide, doxorubicin, vincristine, prednisone, and etoposide (CHOPE) chemotherapy for patients with diffuse lymphoma: Cancer and Leukemia Group B studies 8852 and 8854

BACKGROUND

To address the feasibility and outcome of moderate dose intensification with granulocyte-colony stimulating factor (G-CSF) for patients with aggressive non-Hodgkin lymphoma (NHL), the Cancer and Leukemia Group B (CALGB) conducted two studies evaluating dose-escalated cyclophosphamide and etoposide in the cyclophosphamide, doxorubicin, vincristine, prednisone, etoposide (CHOPE) regimen.

METHODS

Eligibility criteria included histologically documented, diffuse small cleaved, diffuse mixed, diffuse large cell, or immunoblastic lymphoma, Stage III--IV or bulky Stage II disease, and an ECOG performance status of 0--1. CALGB 8852, a group-wide study, accrued 227 patients: 120 patients in the pilot study to determine the maximum tolerated dose (MTD) without G-CSF and 107 in the pilot study of dose-escalated CHOPE with G-CSF. CALGB 8854, a limited-institution, Phase I study, enrolled 38 patients and determined the MTD of CHOPE with G-CSF to be used in CALGB 8852. The MTD in both studies was defined as the dose at which 50% of patients had 1) Grade 4 neutropenia or thrombocytopenia lasting 7 days or more, or 2) Grade 3--4 hemorrhage or nonhematologic toxicity (excluding alopecia, nausea, and emesis), or 3) were prevented from receiving 100% of drug on Day 22.

RESULTS

The MTD of CHOPE without G-CSF was cyclophosphamide 1000 mg/m(2) on Day 1 and etoposide 100 mg/m(2) on Days 1--3 with doxorubicin 50 mg/m(2) on Day 1, vincristine 1.4 mg/m(2) (maximum, 2 mg) on Day 1, and prednisone 100 mg on Days 1--5. With the addition of G-CSF at 200 microg/m(2) on Days 5--19, the MTD was cyclophosphamide 1500 mg/m(2) and etoposide 160 mg/m(2) on Days 1-3 with standard doses of doxorubicin, vincristine, and prednisone. Increasing the dose of G-CSF from 200 microg/m(2) to 400 microg/m(2) did not allow for further dose escalation. The primary toxicity in all cohorts was neutropenia. Four toxic deaths occurred on CALGB 8852. The 5-year failure free survival (FFS) and overall survival (OS) rates for eligible patients on CALGB 8852 were 31% (95% confidence interval [95%CI], 23--39) and 48% (95%CI, 40--57), respectively. The 5-year FFS and OS rates for eligible patients on CALGB 8854 were 34% (95%CI, 17--52) and 51% (95%CI, 33--70), respectively.

CONCLUSIONS

Moderate dose escalation with G-CSF is feasible. However, response and survival rates of patients who receive dose-escalated CHOPE, even with the addition of G-CSF, appear similar to the rates reported with standard-dose CHOP.

Safety and bactericidal activity of rifalazil in patients with pulmonary tuberculosis

Rifalazil, also known as KRM-1648 or benzoxazinorifamycin, is a new semisynthetic rifamycin with a long half-life of approximately 60 h. Rifalazil has potent bactericidal activity against Mycobacterium tuberculosis in vitro and in animal models of tuberculosis (TB). Prior studies in healthy volunteers showed that once-weekly doses of 25 to 50 mg of rifalazil were well tolerated. In this randomized, open-label, active-controlled phase II clinical trial, 65 subjects with sputum smear-positive pulmonary TB received one of the following regimens for the first 2 weeks of therapy: 16 subjects received isoniazid (INH) (5 mg/kg of body weight) daily; 16 received INH (5 mg/kg) and rifampin (10 mg/kg) daily; 17 received INH (5 mg/kg) daily plus 10 mg of rifalazil once weekly; and 16 received INH (5 mg/kg) daily and 25 mg of rifalazil once weekly. All subjects were then put on 6 months of standard TB therapy. Pretreatment and day 15 sputum CFU of M. tuberculosis were measured to assess the bactericidal activity of each regimen. The number of drug-related adverse experiences was low and not significantly different among treatment arms. A transient decrease in absolute neutrophil count to less than 2,000 cells/mm(3) was detected in 10 to 20% of patients in the rifalazil- and rifampin-containing treatment arms without clinical consequences. Decreases in CFU counts were comparable among the four treatment arms; however, the CFU results were statistically inconclusive due to the variability in the control arms. Acquired drug resistance did not occur in any patient. Studies focused on determining a maximum tolerated dose will help elucidate the full anti-TB effect of rifalazil.

Injury induces dedifferentiation of smooth muscle cells and increased matrix-degrading metalloproteinase activity in human saphenous vein

Long-term patency of human saphenous vein bypass grafts is low because of intimal thickening and superimposed atherosclerosis. Matrix-degrading metalloproteinases (MMPs) and changes in vascular smooth muscle cell (VSMC) phenotype are thought to be essential for the VSMC migration that contributes to intimal thickening. We examined VSMC phenotype and MMP activity in saphenous veins obtained before and after surgical manipulation. Surgical preparation of the veins significantly increased pro-MMP-1 expression by 2-fold and significantly reduced tissue inhibitor of MMPs (TIMP)-2 expression, whereas MMP-3 and TIMP-1 were unaffected. Furthermore, caseinolytic and gelatinolytic activities measured by in situ zymography were dramatically elevated by injury. The expression of desmin and smoothelin was significantly decreased by injury, whereas vimentin expression was significantly increased. In addition, these changes in phenotype and MMP activity were localized to a subpopulation of VSMCs, the circumferential medial VSMCs. Our data show that surgical preparative injury induces phenotypic modulation of a subpopulation of medial VSMCs to a synthetic phenotype and increases MMP activity. This may favor matrix degradation, VSMC migration, and the subsequent intimal thickening that leads to graft failure.

Macrophage‐Activating Cytokines in Human Immununodeficiency Virus Type 1–Infected and –Uninfected Patients with Pulmonary Tuberculosis

Tuberculosis (TB) is the most common opportunistic infection in human immunodeficiency virus type 1 (HIV-1)-infected patients globally and occurs throughout the course of HIV-1 disease. Here the production of interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha by peripheral blood mononuclear cells (PBMC) of HIV-1-infected versus -uninfected patients with newly diagnosed pulmonary TB (PTB) was compared. Findings were correlated with cytokine profiles, clinical presentation, and expression of inducible nitric oxide (iNOS). Most HIV-1/PTB patients with a CD4 cell count of 200-500 cells/microL had high IFN-gamma production and radiographic evidence of atypical PTB. Low IFN-gamma production and radiographic evidence of reactivated PTB characterized both HIV-1/PTB patients with a CD4 cell count >or=500 cells/microL and HIV-1-uninfected patients. TNF-alpha levels were similar in all HIV-1/PTB patients, regardless of CD4 cell count. Induction of iNOS in PBMC was low and was associated with low IFN-gamma production. These data underscore the potential pathogenic role of macrophage-activating cytokines in TB in HIV-1-infected patients.

A triple mutant, K319N/H322Q/E325Q, of the lactose permease cotransports H+ with thiodigalactoside

In a previous study, we characterized a lactose permease mutant (K319N/E325Q) that can transport H+ ions with sugar. This result was surprising because other studies had suggested that Glu-325 plays an essential role in H+ binding. To determine if the lactose permease contains one or more auxiliary H+ binding sites, we began with the K319N/E325Q strain, which catalyzes a sugar-dependent H+ leak, and isolated third site suppressor mutations that blocked the H+ leak. Three types of suppressors were obtained: H322Y, H322R, and M299I. These mutations blocked the H+ leak and elevated the apparent Km value for lactose. The M299I and H322Y suppressors could still transport H+ with beta-d-thiodigalactoside (TDG), but the H322R strain appeared uncoupled for H+/sugar cotransport. Four mutant strains containing a nonionizable substitution at codon 322 (H322Q) were analyzed. None of these were able to catalyze uphill accumulation of lactose, however, all showed some level of substrate-induced proton accumulation. The level seemed to vary based on the substrate being analyzed (lactose or TDG). Most interestingly, a triple mutant, K319N/H322Q/E325Q, catalyzed robust H+ transport with TDG. These novel results suggest an alternative mechanism of lactose permease cation binding and transport, possibly involving hydronium ion (H3O+).

Avoidance of abdominal compartment syndrome in damage-control laparotomy after trauma

HYPOTHESIS

Abdominal compartment syndrome (ACS) is a morbid complication of damage-control laparotomy. Moreover, the technique of abdominal closure influences the frequency of ACS.

DESIGN

Retrospective cohort study.

SETTING

Urban level I trauma center.

PATIENTS

We studied 52 patients with trauma who required damage-control laparotomy during the 5 years ending December 31, 1999, and who survived longer than 48 hours.

MAIN OUTCOME MEASURES

Abdominal compartment syndrome, acute respiratory distress syndrome (ARDS), and multiple organ failure (MOF).

RESULTS

Mean (+/- SD) age was 33 +/- 2 years; 38 (73%) were male. Mechanism of injury was blunt in 29 patients (56%), and mean (+/- SD) Injury Severity Score was 28 +/- 2. Development of ARDS and/or MOF was seen in 23 patients (44%); ARDS and MOF increased mortality from 12% (3/26) to 42% (11/26). Abdominal compartment syndrome was a common complication (17/52), and was associated with an increase in ARDS and/or MOF (12 patients [71%] vs 11 patients [31%] without ACS; P =.02, chi(2) test) and death (6 [35%] vs 8 patients [23%] without ACS). Primary fascial closure (n = 10) at the initial laparotomy was associated with ACS in 8 (80%) (P =.001, chi(2) test) and ARDS and/or MOF in 9 (90%) (P =.01, chi(2) test); skin closure (n = 25), with ACS in 6 (24%) and ARDS/MOF in 9 (36%); and Bogotá bag closure (n = 17), with ACS in 3 (18%) and ARDS/MOF in 8 (47%).

CONCLUSIONS

Damage-control laparotomy is associated with frequent complications. In particular, ACS is a serious complication that increases ARDS and/or MOF and mortality. Avoiding primary fascial closure at the initial laparotomy can minimize the risk for ACS.

Percutaneous dilational tracheostomy: a comparison of single- versus multiple-dilator techniques

OBJECTIVE

To compare the safety and efficacy of single- vs. multiple-dilator techniques in the performance of percutaneous dilational tracheostomy.

DESIGN

Prospective randomized trial.

SETTING

Intensive care units at a level 1 trauma center.

PATIENTS

Fifty consecutive patients requiring tracheostomy for airway control or prolonged mechanical ventilatory support.

INTERVENTIONS

Patients were randomized to receive a percutaneous dilational tracheostomy by either the single- or multiple-dilator technique described by Ciaglia.

MEASUREMENTS AND MAIN RESULTS

Percutaneous dilational tracheostomy was performed using the single-dilator technique in 6:01 +/- 3:03 mins and by the multiple-dilator technique in 10:01 +/- 4:26 mins (p <.0006). There were no statistically significant differences in complication rates between the two techniques. No major complications occurred with either technique.

CONCLUSION

The single-dilator percutaneous tracheostomy technique is a safe, cost-effective, and more rapidly performed method for bedside tracheostomy in the intensive care unit.

Quantitative bacillary response to treatment in Mycobacterium tuberculosis infected and M. africanum infected adults with pulmonary tuberculosis

Data regarding possible differences in microbiological response to therapy of disease caused by Mycobacterium tuberculosis and M. africanum are limited. Presenting clinical characteristics and sputum bacillary load during standard short-course chemotherapy in patients with newly-diagnosed pulmonary tuberculosis due to M. tuberculosis (n = 7) and M. africanum (n = 6) were compared. Changes in sputum bacillary load were measured using quantitative acid-fast bacilli smears, colony forming unit assay, and time until positive culture in the BACTEC radiometric system. Presentation and response to short course chemotherapy were comparable between patients infected with M. tuberculosis and those infected with M. africanum.

JFC1, a novel tandem C2 domain-containing protein associated with the leukocyte NADPH oxidase

We have employed a yeast two-hybrid system to screen a B lymphoblast-derived cDNA library, searching for regulatory components of the NADPH oxidase. Using as bait the C-terminal half of p67(phox), which contains both Src homology 3 domains, we have cloned JFC1, a novel human 62-kDa protein. JFC1 possesses two C2 domains in tandem. The C2A domain shows homology with the C2B domain of synaptotagmins. JFC1 mRNA was abundantly expressed in bone marrow and leukocytes. The expression of JFC1 in neutrophils was restricted to the plasma membrane/secretory vesicle fraction. We confirmed JFC1-p67(phox) association by affinity chromatography. JFC1-containing beads pulled down both p67(phox) and p47(phox) subunits from neutrophil cytosol, but when the recombinant proteins were used, only p67(phox) bound to JFC1, indicating that JFC1 binds to the cytosolic complex via p67(phox) without affecting the interaction between p67(phox) and p47(phox). In contrast to synaptotagmins, JFC1 was unable to bind to inositol 1,3,4,5-tetrakisphosphate but did bind to phosphatidylinositol 3,4,5-trisphosphate and to a lesser extent to phosphatidylinositol 3,4-diphosphate. From the data presented here, it is proposed that JFC1 is acting as an adaptor protein between phosphatidylinositol 3-kinase products and the oxidase cytosolic complex.

Adult tuberculosis in the 21st century: pathogenesis, clinical features, and management

This article reviews the significant advances in the past year in the basic and clinical aspects of adult tuberculosis (TB). Further research has deepened our understanding of host susceptibility and resistance mechanisms, including cytotoxicity, apoptosis, and antimicrobial polypeptides such as granulysin. Studies have confirmed the effects of HIV infection on risk of disease and disease manifestations, and have defined the effects of HIV on TB transmission. Recent studies also indicate a possible role for extended treatment of active disease and latent infection in HIV-1 infected individuals. Multidrug-resistant disease has been reported on every continent; rapid molecular approaches to the simultaneous diagnosis of TB and detection of rifampin resistance may facilitate prompt initiation of treatment. TB remains one of the major problems in global health.

Comparative in vitro activity of gemifloxacin, ciprofloxacin, levofloxacin and ofloxacin in a North American surveillance study

The in vitro activity of gemifloxacin, a new fluoroquinolone, was compared to three marketed fluoroquinolones; ciprofloxacin, levofloxacin and ofloxacin against over 4,000 recent clinical isolates covering 29 species isolated in the United States and Canada between 1997-1999. Based on MIC(90)s, gemifloxacin was the most potent fluoroquinolone tested against a majority of Gram-positive isolates: Streptococcus pneumoniae, penicillin resistant S. pneumoniae, macrolide resistant S. pneumoniae, ciprofloxacin non-susceptible (MIC > or = 4 microg/mL) S. pneumoniae, S. pyogenes, S. agalactiae, viridans streptococci, Enterococcus faecalis, methicillin susceptible Staphylococcus aureus, methicillin resistant S. aureus, S. epidermidis, S. hemolyticus, and S. saprophyticus. Against Enterobacteriaceae and aerobic non-Enterobacteriaceae Gram-negatives, gemifloxacin was usually comparable to ciprofloxacin and levofloxacin and more potent than ofloxacin for the following species: Citrobacter freundii, Enterobacter aerogenes, E. cloacae, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, P. vulgaris, Providencia stuartii, Serratia marcescens, Acinetobacter lwoffii, A. baumannii, Burkholderia cepacia, Haemophilus influenzae, H. parainfluenzae, Moraxella catarrhalis, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. Gemifloxacin was generally 16-64 fold more potent than the other fluoroquinolones tested against Gram-positive organisms and retains excellent activity comparable with ciprofloxacin and levofloxacin against a majority of Gram-negative pathogens.

Infection and disease among household contacts of patients with multidrug-resistant tuberculosis

SETTING

Urban public teaching and referral hospital in Espirito Santo, Brazil.

OBJECTIVE

To assess whether rates of infection and progression to active tuberculosis (TB) differed between household contacts of patients with multidrug-resistant (MDR) and drug susceptible (DS) pulmonary tuberculosis.

DESIGN

Household contacts were assessed for evidence of TB infection and disease by purified protein derivative (PPD) skin testing, physical examination, chest X-ray, and sputum smear and culture.

RESULTS

Among 133 close contacts of patients with MDR-TB, 44% were PPD-positive (> or =10 mm) compared to 37% of 231 contacts of the DS-TB cases (P = 0.18, chi2 test, OR 1.2, 95%CI 0.8-2). In a multivariate logistic regression analysis, after allowance for between-household variation in PPD responses, PPD positivity among household contacts of patients with MDR-TB remained comparable to PPD positivity in contacts of patients with DS-TB (OR 2.1, 95%CI 0.7-6.5). Respectively six (4%) and 11 (4%) contacts of the MDR- and DS-TB cases were found to have active TB at the time of initial evaluation or during follow-up (P = 0.78, chi2 test). Five of six contacts of MDR-TB cases and nine of nine contacts of DS-TB cases who developed TB, and for whom drug susceptibility test results were available, had the same bacterial susceptibility profiles as their index cases. DNA fingerprinting analysis of Mycobacterium tuberculosis isolates was identical between household contacts with active TB and the index MDR or DS-TB case for all 14 pairs compared.

CONCLUSION

Our data suggest that the prevalence of tuberculous infection and progression to active TB among household contacts exposed to DS and MDR-TB cases is comparable, despite a longer duration of exposure of contacts to the index case in patients with MDR-TB.

Macro-porosity is necessary for the reduction of neointimal and medial thickening by external stenting of porcine saphenous vein bypass grafts

BACKGROUND

placing external non-restrictive macro-porous stents around porcine vein grafts prevents neointima formation and medial thickening in both the short and long term. Whether the porosity of the stent material influences this effect, however, has not been determined. Therefore, the effect on neointimal and medial thickening of external macro-porous (polyester) and micro-porous (polytetrafluorethylene) stents of equal diameter were compared. The effect on expression of platelet-derived growth factor (PDGF), a potent mediator of vascular smooth muscle cell migration and proliferation and its receptors was also investigated.

METHODS AND RESULTS

saphenous vein-carotid artery interposition grafting was performed in Landrace pigs with external placement of 8 mm diameter macro- and micro-porous stents contralaterally. One month after surgery, graft wall dimensions, PDGF and PDGF receptor expression and cell proliferation using proliferating cell nuclear antigen (PCNA) were measured on histological sections. Macro-porous stents significantly reduced neointimal and medial thickening compared with micro-porous stents (0.1+/-0.02 vs. 0.25+/-0.03 mm, P<0.002, and 0.10+/-0.02 vs. 0.17+/-0.02 mm, P<0.014, respectively). Macro-porous stents significantly reduced the percentage of cells expressing PDGF and PCNA, compared with micro-porous stents (36+/-9 vs. 80+/-7, P < 0.002, and 11+/-3 vs. 21+/-2, P < 0.02, respectively). The percentage of cells expressing PDGF receptors was similar with both the stent types. Adventitial microvessel formation occurred across macro-porous stents but was markedly suppressed by micro-porous stents.

CONCLUSIONS

porosity is crucial to the efficacy of external stents in reducing neointima formation in porcine vein grafts. Decreases in PDGF expression and cell proliferation accompany the reduction in neointima formation. In addition, macro-porous stents allow adventitial microvessels to connect with the vasculature outside the stent, thereby potentially improving oxygenation. Although external stenting is highly effective in reducing neointima formation after vein grafting, the properties of the stent material necessary for this effect have not been defined. This study establishes that macro-porosity is one essential feature required to reduce PDGF expression cell proliferation and neointima formation.

Inhibition of isoniazid-induced expression of Mycobacterium tuberculosis antigen 85 in sputum: potential surrogate marker in tuberculosis chemotherapy trials

Mycobacterium tuberculosis antigen 85 is induced in vitro by isoniazid (INH); its sustained induction in sputum during tuberculosis (TB) therapy predicts relapse. In this trial, rifampin or rifalazil inhibited the induction of sputum antigen 85 by INH in a dose-dependent fashion. This approach may facilitate the evaluation of new TB drugs.

HIV-1-related pleural tuberculosis: elevated production of IFN-gamma, but failure of immunity to Mycobacterium tuberculosis

BACKGROUND

Pleural tuberculosis can resolve spontaneously, suggesting that the inflammatory process may represent a protective immune response. However, pleural tuberculosis is strongly associated with HIV infection. It has been suggested that cell-mediated immune responses may be reduced, and direct bacterial invasion may have a role in pathogenesis, in HIV-positive cases. To test this hypothesis, we compared production of the pro-inflammatory cytokines, interferon (IFN)-gamma and tumour necrosis factor(TNF)-alpha, production of the immunosuppressive cytokine, interleukin (IL)-10, and mycobacterial culture positivity, in HIV-negative and HIV-positive patients with pleural tuberculosis.

METHODS

Cytokine levels were measured in serum and pleural fluid, and in supernatants of blood and pleural fluid stimulated in vitro using mycobacterial antigens. Intracellular IFN-gamma and TNF-alpha production was measured after stimulation with phorbol myristate acetate and ionomycin in vitro.

RESULTS

IFN-gamma was strikingly elevated in serum and pleural fluid in HIV-positive, compared to HIV-negative subjects (P < or = 0.02). TNF-alpha was elevated, but this was not statistically significant. IL-10 levels were higher in serum (P < 0.001), but similar in pleural fluid. IFN-gamma responses to soluble mycobacterial antigen in vitro were reduced in peripheral blood (P = 0.006), but not pleural fluid, of HIV-positive subjects. Intracellular cytokine staining suggested that CD8+ T cells were a major source of IFN-gamma in HIV-positive subjects. The proportion of subjects with a positive culture for Mycobacterium tuberculosis from pleural fluid was higher in the HIV-positive group.

CONCLUSIONS

HIV-positive patients with pleural tuberculosis show elevated production of IFN-gamma, for which CD8+ T cells may be a major source. Mycobacterium tuberculosis can proliferate despite high levels of pro-inflammatory cytokines.

Augmentation of apoptosis and interferon-gamma production at sites of active Mycobacterium tuberculosis infection in human tuberculosis

Pleural tuberculosis (TB) was employed as a model to study T cell apoptosis at sites of active Mycobacterium tuberculosis (MTB) infection in human immunodeficiency virus (HIV)-coinfected (HIV/TB) patients and patients infected with TB alone. Apoptosis in blood and in pleural fluid mononuclear cells and cytokine immunoreactivities in plasma and in pleural fluid were evaluated. T cells were expanded at the site of MTB infection, irrespective of HIV status. Apoptosis of CD4 and non-CD4 T cells in the pleural space occurred in both HIV/TB and TB. Interferon (IFN)-gamma levels were increased in pleural fluid, compared with plasma. Spontaneous apoptosis correlated with specific loss of MTB-reactive, IFN-gamma-producing pleural T cells. Immunoreactivities of molecules potentially involved in apoptosis, such as tumor necrosis factor-alpha, Fas-ligand, and Fas, were increased in pleural fluid, compared with plasma. These data suggest that continued exposure of immunoreactive cells to MTB at sites of infection may initiate a vicious cycle in which immune activation and loss of antigen-responsive T cells occur concomitantly, thus favoring persistence of MTB infection.

Resuscitation with a blood substitute abrogates pathologic postinjury neutrophil cytotoxic function

BACKGROUND

Resuscitation with oxygen-carrying fluids is critically important in the patient with hemorrhagic shock caused by trauma. However, it is clear that a number of biologic mediators present in stored blood (packed red blood cells [PRBCs]) have the potential to exacerbate early postinjury hyperinflammation and multiple organ failure through priming of circulating neutrophils (PMNs). PolyHeme (Northfield Laboratories, Evanston, IL), a hemoglobin-based substitute that is free of priming agents, provides an alternative. We hypothesized that PMN priming would be attenuated in patients resuscitated with PolyHeme in lieu of stored blood.

METHODS

Injured patients requiring urgent transfusion were given either PolyHeme (up to 20 units) or PRBCs. Early postinjury PMN priming was measured via beta-2 integrin expression, superoxide production, and elastase release.

RESULTS

Treatment groups were comparable with respect to extent of injury and early physiologic compromise. PMNs from patients resuscitated with PRBCs showed priming in the early postinjury period by all three measures. No such priming was evident in patients resuscitated with PolyHeme.

CONCLUSION

The use of a blood substitute in the early postinjury period avoids PMN priming and may thereby provide an avenue to decrease the incidence or severity of postinjury multiple organ failure.

Atherosclerotic plaque rupture in the apolipoprotein E knockout mouse

The rupture of an atherosclerotic plaque is the main underlying cause of coronary artery thrombotic occlusion and subsequent myocardial infarction, but research into the causes and treatment of plaque rupture is hampered by the lack of a suitable animal model. Although complex atherosclerotic plaques can be induced in a number of experimental animal systems, in none of these is plaque rupture an established feature. We have surveyed branch points in the carotid arteries and aortas of apolipoprotein E knockout mice fed a diet supplemented with 21% lard and 0.15% cholesterol for up to 14 months. Six male and five female mice were used. Four of the male mice and four of the female mice died, after 46+/-3 weeks of feeding (range 37-59 weeks). Lumenal thrombus associated with atherosclerotic plaque rupture was observed in three male and all four female mice. In six of these seven mice, an atherosclerotic plaque rupture was found where the brachiocephalic artery branches into the right common carotid and right subclavian arteries. The ruptures were characterised by fragmentation and loss of elastin in the fibrous caps of relatively small and lipid-rich plaques overlying large complex lesions, with intraplaque haemorrhage. Immunocytochemical analysis revealed loss of smooth muscle cells from ruptured caps. These data suggest that long-term fat-feeding of apolipoprotein E knockout mice is a useful and reproducible model of atherosclerotic plaque rupture, and that these ruptures occur predominantly in the brachiocephalic artery.

Removal of an intrathoracic migrated fixation pin by thoracoscopy

Migration of orthopedic fixation pins into the thoracic cavity can result in perforation of pulmonary vasculature, aorta, bronchus, atrium, or ventricle. Prompt diagnosis and treatment is tantamount in preventing devastating consequences. A patient who had fixation of a right humeral fracture weeks later had intrathoracic migration of a fixation pin, found by routine postoperative radiographic examination. Because the patient was asymptomatic, we removed the pin with a thoracoscopic operation. The foreign body was retrieved successfully without intraoperative or postoperative complication.

Evidence for a two-electron transfer using the all-ferrous Fe protein during nitrogenase catalysis

The nitrogenase-catalyzed H(2) evolution and acetylene-reduction reactions using Ti(III) and dithionite (DT) as reductants were examined and compared under a variety of conditions. Ti(III) is known to make the all-ferrous Fe protein ([Fe(4)S(4)](0)) and lowers the amount of ATP hydrolyzed during nitrogenase catalysis by approximately 2-fold. Here we further investigate this behavior and present results consistent with the Fe protein in the [Fe(4)S(4)](0) redox state transferring two electrons ([Fe(4)S(4)](2+)/[Fe(4)S(4)](0)) per MoFe protein interaction using Ti(III) but transferring only one electron ([Fe(4)S(4)](2+)/[Fe(4)S(4)](1+)) using DT. MoFe protein specific activity was measured as a function of Fe:MoFe protein ratio for both a one- and a two-electron transfer reaction, and nearly identical curves were obtained. However, Fe protein specific activity curves as a function of MoFe:Fe protein ratio showed two distinct reactivity patterns. With DT as reductant, typical MoFe inhibition curves were obtained for operation of the [Fe(4)S(4)](2+)/[Fe(4)S(4)](1+) redox couple, but with Ti(III) as reductant the [Fe(4)S(4)](2+)/[Fe(4)S(4)](0) redox couple was functional and MoFe inhibition was not observed at high MoFe:Fe protein ratios. With Ti(III) as reductant, nitrogenase catalysis produced hyperbolic curves, yielding a V(max) for the Fe protein specific activity of about 3200 nmol of H(2) min(-1) mg(-1) Fe protein, significantly higher than for reactions conducted with DT as reductant. Lag phase experiments (Hageman, R. V., and Burris, R. H. (1978) Proc. Natl. Acad. Sci. U. S. A. 75, 2699-2702) were carried out at MoFe:Fe protein ratios of 100 and 300 using both DT and Ti(III). A lag phase was observed for DT but, with Ti(III) product formation, began immediately and remained linear for over 30 min. Activity measurements using Av-Cp heterologous crosses were examined using both DT and Ti(III) as reductants to compare the reactivity of the [Fe(4)S(4)](2+)/[Fe(4)S(4)](1+) and [Fe(4)S(4)](2+)/[Fe(4)S(4)](0) redox couples and both were inactive. The results are discussed in terms of the Fe protein transferring two electrons per MoFe protein encounter using the [Fe(4)S(4)](2+)/[Fe(4)S(4)](0) redox couple with Ti(III) as reductant.

Demonstrations of the influence of the eating environment on food acceptance

In two independent demonstrations, pre-prepared food was served in different environments: first, identical prepared meals were served in both a training restaurant and in a student cafeteria; second, a prepared main dish was served in a food science laboratory class, and as part of an entire meal in two student cafeterias and in a training restaurant. In the training restaurants and in the student cafeterias, people selected and paid for their meals. The acceptability ratings of the food served varied across the three different environments in the following order: restaurant>laboratory>cafeteria. Differences in acceptance were attributed to contextual effects and the expectations they produce, actual product differences, and a number of possible covariates. Ratings of sensory attributes tended to mirror the acceptability effects. The difficulty of comparing contexts within actual food service systems is discussed.

Analysis of steady state Fe and MoFe protein interactions during nitrogenase catalysis

Steady state kinetic measurements are reported for nitrogenase from Azotobacter vinelandii (Av) and Clostridium pasteurianum (Cp) under a variety of conditions, using dithionite as reductant. The specific activities of Av1 and Cp1 are determined as functions of Av2:Av1 and Cp2:Cp1, respectively, at component protein ratios from 0.4 to 50, and conform to a simple hyperbolic rate law for the interaction of Av2 with Av1 and Cp2 with Cp1. The specific activities of Av2 and Cp2 are also measured as a function of increasing Av1 and Cp1 concentrations, producing 'MoFe inhibition' at large MoFe:Fe ratios. When the rate of product formation under MoFe inhibited conditions is re-plotted as increasing Av2:Av1 or Cp2:Cp1 ratios, sigmoidal kinetic behavior is observed, suggesting that the rate constants in the Thorneley and Lowe (T&L) model are more dependent upon the oxidation level of MoFe protein than previously suspected [R.N.F. Thorneley, D.J. Lowe, Biochem. J. 224 (1984) 887-894], at least when applied to Av and Cp. Calculation of Hill coefficients gave values of 1.7-1.9, suggesting a highly cooperative Fe-MoFe protein interaction in both Av and Cp nitrogenase catalysis. The T&L model lacks analytical solutions [R.N.F. Thorneley, D.J. Lowe, Biochem. J. 215 (1983) 393-404], so the ease of its application to experimental data is limited. To facilitate the study of steady state kinetic data for H(2) evolution, analytical equations are derived from a different mechanism for nitrogenase activity, similar to that of Bergersen and Turner [Biochem. J. 131 (1973) 61-75]. This alternative cooperative model assumes that two Fe proteins interact with one MoFe protein active site. The derived rate laws for this mechanism were fitted to the observed sigmoidal behavior for low Fe:MoFe ratios (<0.4), as well as to the commonly observed hyperbolic behavior for high values of Fe:MoFe for both Av and Cp.

Mechanistic interpretation of the dilution effect for Azotobacter vinelandii and Clostridium pasteurianum nitrogenase catalysis

Nitrogenase activity for Clostridium pasteurianum (Cp) at a Cp2:Cp1 ratio of 1.0 and Azotobacter vinelandii (Av) at Av2:Av1 protein ratios (R) of 1, 4 and 10 is determined as a function of increasing MoFe protein concentration from 0.01 to 5 microM. The rates of ethylene and hydrogen evolution for these ratios and concentrations were measured to determine the effect of extreme dilution on nitrogenase activity. The experimental results show three distinct types of kinetic behavior: (1) a finite intercept along the concentration axis (approximately 0.05 microM MoFe); (2) a non-linear increase in the rate of product formation with increasing protein concentration (approximately 0.2 microM MoFe) and (3) a limiting linear rate of product formation at high protein concentrations (>0.4 microM MoFe). The data are fitted using the following rate equation derived from a mechanism for which two Fe proteins interact cooperatively with a single half of the MoFe protein. (see equation) The equation predicts that the cubic dependence in MoFe protein gives rise to the non-linear rate of product formation (the dilution effect) at very low MoFe protein concentrations. The equation also predicts that the rate will vary linearly at high MoFe protein concentrations with increasing MoFe protein concentration. That these limiting predictions are in accord with the experimental results suggests that either two Fe proteins interact cooperatively with a single half of the MoFe protein, or that the rate constants in the Thorneley and Lowe model are more dependent upon the redox state of MoFe protein than previously suspected [R.N. Thornley and D. J. Lowe, Biochem. J. 224 (1984) 887-894]. Previous Klebsiella pneumoniae and Azotobacter chroococcum dilution results were reanalyzed using the above equation. Results from all of these nitrogenases are consistent and suggest that cooperativity is a fundamental kinetic aspect of nitrogenase catalysis.

Enhanced proliferation and differentiation of human articular chondrocytes when seeded at low cell densities in alginate in vitro

Dedifferentiated human articular chondrocytes exhibited a wide variation in their capacity to proliferate and redifferentiate in an alginate suspension culture system. The greatest extent of proliferation and redifferentiation was seen to be dependent on the formation of clonal populations of chondrocytes and correlated inversely with the initial cell seeding density. Redifferentiating chondrocytes seeded at low density (1 x 10(4) cells/ml alginate) compared with chondrocytes that were seeded at high density (1 x 10(6) cells/ml alginate) showed a nearly 3-fold higher median increase in cell number. a 19-fold greater level of type-II collagen mRNA expression, a 4-fold greater level of aggrecan mRNA expression, and a 6-fold greater level of sulfated glycosaminoglycan deposition at 4 weeks of culture. Matrix molecules from low-density cultures were assembled into chondrocyte-encapsulated, spherical extracellular matrices that were readily visualized in sections from 12-week cultures stained with antibodies against types I and II collagen and aggrecan. Ultrastructural analysis of 12-week low-density cultures confirmed the presence of thin collagen fibrils throughout the matrix.

Efficacy of an unsupervised 8-month rifampicin-containing regimen for the treatment of pulmonary tuberculosis in HIV-infected adults. Uganda-Case Western Reserve University Research Collaboration

SETTING

National Tuberculosis Treatment Centre, Mulago Hospital, Kampala, Uganda.

OBJECTIVE

To assess the efficacy of a daily, self-administered 8-month rifampicin-containing regimen for the treatment of pulmonary tuberculosis (TB) in human immunodeficiency virus (HIV) infected adults.

DESIGN

Treatment outcomes in patients with pulmonary TB treated with a single 8-month regimen and followed in a prospective epidemiological study.

RESULTS

Two hundred and sixty-five HIV-infected and 26 non-HIV-infected adults with initial episodes of pulmonary tuberculosis were treated with 2 months of daily isoniazid (INH), rifampicin (RMP), ethambutol and pyrazinamide followed by 6 months of daily INH + RMP. Median follow-up was 17.8 months. Ninety-five per cent of the HIV-infected and all of the non-HIV-infected patients who had sputum examined were sputum culture negative after 2 months of treatment. Twenty-two HIV-infected and no non-HIV-infected patients died during treatment. Relapse rates were 8.4% (5.9 per 100 person-years of observation [PYO], 95%CI 3.2-8.6) among HIV-infected patients and 4.5% (2.1/100 PYO, 95%CI 0-7.8) for non-HIV-infected patients. Adverse drug reactions occurred in 37% of the HIV-infected patients; most were minor and self-limiting.

CONCLUSION

An 8-month RMP-containing regimen was well tolerated and effective in the treatment of HIV-infected adults with initial episodes of pulmonary TB. Relapse rates were similar to those reported with 6-month short-course regimens in HIV-infected individuals. Decisions about the duration of anti-tuberculosis treatment for HIV-infected adults must balance programme resources and the likelihood of poor compliance with longer regimens with the potential for a modest decrease in relapses with longer treatment.

Slowly resolving and nonresolving pneumonia. Questions to ask when response is delayed

What is the proper course of action when pneumonia symptoms seem to linger? Is the disease running a typical course, or is further evaluation needed? Dr Johnson addresses these important questions with an outline of risk factors for delayed resolution and a detailed listing of diagnostic considerations. He also discusses reasonable timing of further studies and the usefulness of radiography and fiberoptic bronchoscopy.

Simultaneous comparison of reactivity to purified protein derivative RT-23 and Tubersol in health care workers in Vitória, Brazil

Questions have recently been raised regarding the potency of purified protein derivative (PPD) RT-23, the tuberculin most widely used world-wide for skin testing. We performed simultaneous testing with PPD RT-23 and Tubersol to compare these reagents during a tuberculin survey of 202 adult health care workers at a large teaching hospital in 1997. Individuals were tested with 2 tuberculin units (TU) PPD RT-23 and 5 TU Tubersol using the Mantoux method. Using a 10 mm cut-point for a positive PPD test, 39% of the health care workers were positive when tested with Tubersol and 35% were positive when tested with PPD RT-23. The median PPD size with Tubersol was 4 mm (interquartile range = 0-12 mm) compared to 2 mm (interquartile range = 0-12 mm) with PPD RT-23. PPD skin test reactivity with the two reagents was highly correlated (Spearman's rank coefficient, rho = 0.92; P = 0.01, two tailed). Concordance between the skin test reaction size with the two antigens did not differ based on age, sex or prior BCG vaccination. Mantoux skin test reactivity in health care workers in an area with a high prevalence of tuberculosis was comparable with PPD RT-23 and Tubersol.

A comparative In vitro surveillance study of gemifloxacin activities against 2,632 recent Streptococcus pneumoniae isolates from across Europe, North America, and South America. The Gemifloxacin Surveillance Study Research Group

From 1997 to 1999, 94 study centers in 15 European, 3 North American, and 2 South American countries contributed 2,632 isolates of Streptococcus pneumoniae to an international antimicrobial susceptibility testing study. Only 62.0% of isolates were susceptible to penicillin, while 22.3% were penicillin intermediate and 15.6% were penicillin resistant. Resistance to trimethoprim-sulfamethoxazole (24.4%), azithromycin (26.0%), and clarithromycin (27.1%) was also highly prevalent. For the penicillin-resistant isolates (n = 411), the MICs at which 90% of isolates are inhibited (MIC(90)s) for gemifloxacin, levofloxacin, ofloxacin, clarithromycin, and azithromycin were 0.03, 1, 2, >16, and >64 microgram/ml, respectively. Similarly, for isolates resistant to both azithromycin and clarithromycin (n = 649), gemifloxacin, levofloxacin, ofloxacin, and penicillin MIC(90)s were 0.03, 1, 2, and 4 microgram/ml, respectively. Overall rates of resistance to trovafloxacin (0.3%), levofloxacin (0.3%), grepafloxacin (0.6%), and ofloxacin (0.7%) were low. For ofloxacin-intermediate and -resistant isolates (n = 142), gemifloxacin had the lowest MIC(90) (0.12 microgram/ml) compared to the MIC(90)s of trovafloxacin (0.5 microgram/ml), grepafloxacin (1 microgram/ml), and levofloxacin (2 microgram/ml). For all S. pneumoniae isolates tested, gemifloxacin MICs were </=0.5 microgram/ml, suggesting that gemifloxacin has the potential to be used as a treatment for pneumococcal infections, including those arising from isolates resistant to beta-lactams and macrolides.

Quadrupole radiation from terahertz dipole antennas

We report what is to our knowledge the first detailed investigation of the polarization state of radiation from lens-coupled terahertz dipole antennas. The radiation exhibits a weak but measurable component that is polarized orthogonally to the orientation of the emitter dipole. The angular radiation pattern of this cross-polarized emission reveals that it is quadrupolar, rather than dipolar, in nature. One can understand this result by taking into account the photocurrent flowing in the strip lines that feed the dipole antenna. A Fresnel-Kirchhoff scalar diffraction calculation is used for calculating the frequency-dependent angular distribution of the radiation pattern, providing satisfactory agreement with the measurements.

Abdominal perfusion pressure: a superior parameter in the assessment of intra-abdominal hypertension

OBJECTIVE

To assess the clinical utility of abdominal perfusion pressure (mean arterial pressure minus intra-abdominal pressure) as both a resuscitative endpoint and predictor of survival in patients with intra-abdominal hypertension.

METHODS

144 surgical patients treated for intra-abdominal hypertension between May 1997 and June 1999 were retrospectively reviewed. Multivariate logistic regression and receiver operating characteristic curve analysis of common physiologic variables and resuscitation endpoints were performed to determine the decision thresholds for each variable that predict patient survival.

RESULTS

Abdominal perfusion pressure was statistically superior to both mean arterial pressure and intravesicular pressure in predicting patient survival from intra-abdominal hypertension and abdominal compartment syndrome. Multiple regression analysis demonstrated that abdominal perfusion pressure was also superior to other common resuscitation endpoints, including arterial pH, base deficit, arterial lactate, and hourly urinary output.

CONCLUSION

Abdominal perfusion pressure appears to be a clinically useful resuscitation endpoint and predictor of patient survival during treatment for intra-abdominal hypertension and abdominal compartment syndrome.

Serial causation: occasion setting in a causal induction task

The temporal relations among candidate causes were studied in a causal induction task using a design that is known to produce occasion setting in animal learning preparations. For some subset of the observations, one event, the occasion setter, was accompanied by another event, the conditional cause; for another subset of the observations, the conditional cause occurred alone. The efficacy of the conditional cause depended on whether it was or was not accompanied by the occasion setter. Participants used the occasion setter to modulate their effect expectancy to the conditional cause when the events were presented serially, but not simultaneously. Current causal induction models are unable to account for the full range of effects that we observed; the relative roles of time, attention, and cue distinctiveness are discussed.

An unusual case of corneal perforation secondary to Pseudomonas keratitis complicating a patient's surgical/trauma intensive care unit stay

We report a case of corneal perforation secondary to bacterial keratitis caused by Pseudomonas aeruginosa in a trauma patient in our intensive care unit. A 43-year-old man was involved in a motorcycle crash and suffered multiple injuries necessitating a prolonged intensive care unit (ICU) stay. Subsequently P. aeruginosa was cultured from his sputum, blood, and open abdomen. He developed a bacterial keratitis in his right eye, which also grew P. aeruginosa. This infection rapidly progressed to corneal perforation requiring a Gunderson conjunctival flap and lateral tarsorrhaphy in addition to aggressive antibiotic treatment. At the time of discharge from the hospital the patient had the return of vision to light only in his right eye. Corneal perforation is an unusual event in the ICU. Prevention or early detection of bacterial keratitis with aggressive antibiotic treatment is needed to prevent such complications. Pseudomonas is one of the more virulent organisms that can infect the cornea and early identification is paramount for a good outcome. Management of this complicated case is discussed and the limited amount of literature on nosocomial bacterial keratitis in the ICU is reviewed.

Subungual melanoma. A review of 93 cases with identification of prognostic variables

From 1970 to 1996, 93 patients received diagnoses of subungual melanoma. Followup data were complete on all patients and reviewed with a median duration of followup of 5.2 years. This study identifies significant clinicopathologic variables that affect survival and provides the orthopaedic surgeon assistance in the early diagnosis and treatment of this lesion. Eight-three percent of patients presented with Stage I disease, whereas 17% had nodal or distant disease. Fifty-three percent had locally advanced disease at presentation. Twelve percent of the patients were African-American. Fifty-five percent of the lesions arose on the hands with thumb involvement predominating in more than half of these cases. Operative therapy consisted of amputation. Elective lymph node dissection was performed in 34 patients (37%) for Stage I tumors of intermediate thickness. Therapeutic node dissection was required in 16 patients (17%) for positive nodes. Five-year survival was 74% for patients with Stage I disease and 40% for patients with Stage II disease. Statistical analysis identified stage at diagnosis, Clark and Wihm's level, the patient's race, and the presence of ulceration as prognostic variables affecting survival. The diagnosis of subungual melanoma carries a grave prognosis and often is misdiagnosed in the early stages. The treatment of choice is amputation at the appropriate level.

Phase II study of infusional chemotherapy with doxorubicin, vincristine and etoposide plus cyclophosphamide and prednisone (I-CHOPE) in resistant diffuse aggressive non-Hodgkin's lymphoma: CALGB 9255. Cancer and Leukemia Group B

BACKGROUND

Patients with resistant diffuse aggressive non-Hodgkin's lymphoma (DA-NHL) have a poor prognosis. Studies have suggested infusional therapy may be beneficial.

PATIENTS AND METHODS

This trial used an infusional regimen called I-CHOPE in resistant patients who had previously received only bolus CHOPE or CHOP regimen. Resistance was defined as: a) primary refractory disease, b) progression on therapy, c) partial response, d) complete remission lasting less than one year. Eligibility criteria included a diagnosis of DA-NHL (IWF E-H), no prior irradiation and adequate organ function.

RESULTS

Thirty-seven patients were entered and twenty-nine were eligible. Reasons for ineligibility were incorrect histology (5) and other (3). The median age was 57 years (range 29-81) with 21 males. The performance status scores were: 0 (12 patients); 1 (9 patients); 2 (8 patients). Prior therapy consisted of standard CHOP (26 patients), bolus CHOPE (2 patients), high dose CHOP (1 patient). Therapy consisted of a 120 hour continuous intravenous infusion of doxorubicin 10 mg/m2/day, vincristine 0.28 mg/m2/day (maximum 0.4 mg/day), and etoposide 48 mg/m2/day. Cyclophosphamide 750 mg/m2 was given as an i.v. bolus day 6 and prednisone was given at 100 mg/day p.o. on days 1-5. G-CSF was allowed for myelosuppression. The overall response rate was 48% (CR 17%; PR 31%). Freedom from progression was 24% at six months and 8% at one year. Survival was 69% at six months and 40% at one year. In an exploratory analysis a prior CR or PR predicted response to I-CHOPE. Twelve of sixteen patients who had a CR/PR on previous therapy responded while two of thirteen who had no prior response, responded to I-CHOPE (P = 0.003). The toxicity was tolerable with grade 3-4 hematologic toxicity being leucopenia 94% and thrombocytopenia 41%. The grade 3-4 non-hematologic toxicities were infection in 28%, phlebitis in 11%, and stomatitis in 15%.

CONCLUSIONS

I-CHOPE can induce responses in this group of patients with a poor prognosis, but most were seen in those who had previously had a response to bolus chemotherapy.

Long-term satisfaction and psychological and social function following bilateral prophylactic mastectomy

CONTEXT

Prophylactic mastectomy is a preventive option for women who wish to reduce their risk of breast cancer. There has been concern about possible negative psychological sequelae following this procedure. However, few data are available regarding long-term satisfaction and psychological and social function following this procedure.

OBJECTIVE

To evaluate patients' long-term satisfaction and psychological and social function following prophylactic mastectomy.

DESIGN, SETTING, AND PARTICIPANTS

Descriptive study of all women known to be alive (n = 609) who had a family history of breast cancer and elected to undergo bilateral prophylactic mastectomy at a large, tertiary US health care clinic between 1960 and 1993, 94% (n = 572) of whom completed a study questionnaire.

MAIN OUTCOME MEASURES

Satisfaction with procedure and effects on psychological and social function, based on responses to the study-specific questionnaire.

RESULTS

Mean time from prophylactic mastectomy to last follow-up was 14.5 years. Most women (70%) were satisfied with the procedure; 11% were neutral; and 19% were dissatisfied. Among the psychological and social variables, the most striking finding was that 74% reported a diminished level of emotional concern about developing breast cancer. The majority of women reported no change/favorable effects in levels of emotional stability (68%/23%), level of stress (58%/28%), self-esteem (69%/13%), sexual relationships (73%/4%), and feelings of femininity (67%/8%). Forty-eight percent reported no change in their level of satisfaction with body appearance; 16% reported favorable effects. However, 9%, 14%, 18%, 23%, 25%, and 36% reported negative effects in these 6 variables, respectively.

CONCLUSIONS

This study suggests that positive outcomes following prophylactic mastectomy include decreased emotional concern about developing breast cancer and generally favorable psychological and social outcomes. These must be weighed against the irreversibility of the decision, potential problems with implants and reconstructive surgery, and occurrence of adverse psychological and social outcomes in some women. JAMA. 2000;284:319-324