The true prevalence of pulmonary lymphangioleiomyomatosis (LAM) in patients with tuberous sclerosis complex (TSC) is unknown. The prevalence of LAM, radiological features, and lung function in patients with TSC was measured. The presence of LAM, as defined by the presence of cysts by high-resolution chest computed tomography (HRCT) scan, was determined in patients with TSC without prior pulmonary disease (Group 1). To determine the significance of early detection, severity of disease in screened patients (Group 1) was compared with that in patients with TSC with a prior diagnosis of LAM (Group 2). Forty-eight patients with TSC and no prior history of LAM were screened. Of the 38 females, 13 (34%) had LAM; LAM was absent in males. Lung function was preserved in patients with TSC who were found to have LAM by screening. In patients previously known to have LAM, FEV(1) and DL(CO) correlated inversely with severity of disease as assessed by CT scan. The prevalence of LAM in women with TSC was 34%, approximately 10-fold that previously reported, consistent with a large hitherto unrecognized subclinical population of patients at risk for pulmonary complications.

Herpes simplex virus type 1 (HSV-1) infection alters the phosphorylation of the large subunit of RNA polymerase II (RNAP II), resulting in the depletion of the hypophosphorylated and hyperphosphorylated forms of this polypeptide (known as IIa and IIo, respectively) and induction of a novel, alternatively phosphorylated form (designated IIi). We previously showed that the HSV-1 immediate-early protein ICP22 is involved in this phenomenon, since induction of IIi and depletion of IIa are deficient in cells infected with 22/n199, an HSV-1 ICP22 nonsense mutant (S. A. Rice, M. C. Long, V. Lam, P. A. Schaffer, and C. A. Spencer, J. Virol. 69:5550-5559, 1995). However, depletion of IIo still occurs in 22/n199-infected cells. This suggests either that another viral gene product affects the RNAP II large subunit or that the truncated ICP22 polypeptide encoded by 22/n199 retains residual activity which leads to IIo depletion. To distinguish between these possibilities, we engineered an HSV-1 ICP22 null mutant, d22-lacZ, and compared it to 22/n199. The two mutants are indistinguishable in their effects on the RNAP II large subunit, suggesting that an additional viral gene product is involved in altering RNAP II. Two candidates are UL13, a protein kinase which has been implicated in ICP22 phosphorylation, and the virion host shutoff (Vhs) factor, the expression of which is positively regulated by ICP22 and UL13. To test whether UL13 is involved, a UL13-deficient viral mutant, d13-lacZ, was engineered. This mutant was defective in IIi induction and IIa depletion, displaying a phenotype very similar to that of d22-lacZ. In contrast, a Vhs mutant had effects that were indistinguishable from wild-type HSV-1. Therefore, UL13 but not the Vhs function plays a role in modifying the RNAP II large subunit. To study the potential role of UL13 in viral transcription, we carried out nuclear run-on transcription analyses in infected human embryonic lung cells. Infections with either UL13 or ICP22 mutants led to significantly reduced amounts of viral genome transcription at late times after infection. Together, our results suggest that ICP22 and UL13 are involved in a common pathway that alters RNAP II phosphorylation and that in some cell lines this change promotes viral late transcription.

A direct antigen-capture ELISA based on the detection of mycobacterial lipoarabinomannan (LAM) in unprocessed urine was evaluated for its usefulness in clinical practice. In Tanzania, 231 patients with suspected pulmonary tuberculosis (TB) and 103 healthy volunteers were screened with standard TB tests and with the new LAM-ELISA. Of 132 patients with confirmed pulmonary mycobacterial disease (positive sputum culture), 106 were positive using the LAM-ELISA (sensitivity 80.3%). In comparison, the sensitivity of acid-fast bacilli (AFB) sputum microscopy was 62.1% (82 of 132 confirmed cases). Of the 231 patients, 17 were both culture- and AFB-negative, but had typical radiographic signs of pulmonary mycobacterial infection and did not respond to antibiotic treatment. Of these 17 patients, 13 (76.5%) had positive LAM-ELISA test results. To define the specificity of the assay, urine samples from 103 healthy volunteers were also screened using LAM-ELISA. All but one had an optical density below the cut-off (specificity 99%). Of interest was a significant correlation between level of microscopic density of mycobacteria in sputum and LAM antigen concentration in urine (chi2=8.44). The LAM-ELISA is a field-adapted tool that can improve screening standards in countries with a high incidence of TB.

The effect of ethambutol (EMB) is primarily on polymerization steps in the biosynthesis of the arabinan component of cell wall arabinogalactan (AG) of Mycobacterium smegmatis. Inhibition of the synthesis of the arabinan of lipoarabinomannan (LAM) occurred later, and thus in the cases of AG and LAM, the polymerization of D-arabinofuranose apparently involves separate pathways. While the synthesis of these arabinans was normal in an EMB-resistant isogeneic strain, the addition of EMB to the resistant strain resulted in partial inhibition of the synthesis of the arabinan of LAM and the emergence of a novel, truncated form of LAM, indicating partial susceptibility of the resistant gene(s) and providing a new intermediate in the LAM biosynthetic sequence. A consequence of inhibition of AG arabinan biosynthesis is the lack of new sites for mycolate attachment and thus the channeling of mycolate residues into a variety of free lipids which then accumulate. The primary biochemical effects of EMB can be explained by postulating separate AG and LAM pathways catalyzed by a variety of extramembranous arabinosyl transferases with various degrees of sensitivity to EMB.

Mycobacteria possess various immunomodulatory molecules on the cell wall. Mannose-capped lipoarabinomannan (Man-LAM), a major lipoglycan of Mycobacterium tuberculosis, has long been known to have both inhibitory and stimulatory effects on host immunity. However, the direct Man-LAM receptor that explains its pleiotropic activities has not been clearly identified. Here, we report that a C-type lectin receptor Dectin-2 (gene symbol Clec4n) is a direct receptor for Man-LAM. Man-LAM activated bone-marrow-derived dendritic cells (BMDCs) to produce pro- and anti-inflammatory cytokines, whereas it was completely abrogated in Clec4n(-/-) BMDCs. Man-LAM promoted antigen-specific T cell responses through Dectin-2 on DCs. Furthermore, Man-LAM induced experimental autoimmune encephalitis (EAE) as an adjuvant in mice, whereas Clec4n(-/-) mice were resistant. Upon mycobacterial infection, Clec4n(-/-) mice showed augmented lung pathology. These results demonstrate that Dectin-2 contributes to host immunity against mycobacterial infection through the recognition of Man-LAM.

Mycobacterium tuberculosis, the causative agent of tuberculosis, is one of the most effective human pathogens and the molecular basis of its virulence remains poorly understood. Here, we review our current knowledge about the structure and biosynthesis of the mycobacterial cell-wall lipoglycans, lipoarabinomannans (LAM). LAM are ubiquitous of mycobacteria and appear as the most potent non-peptidic molecules to modulate the host immune response. Nevertheless, LAM structure differs according to the mycobacterial species and three types of LAM have been described: mannose-capped LAM (ManLAM), phospho-myo-inositol-capped LAM (PILAM) and non-capped LAM (AraLAM). The type of capping is a major structural feature determining the ability of LAM to modulate the immune response. ManLAM, found in slow-growing mycobacteria, such as M. tuberculosis, have been demonstrated to be powerful anti-inflammatory molecules and emerge as key virulence factors that may be relevant drug targets. LAM-like molecules are not only confined to mycobacteria but are also present in actinomycetes (including the genera Rhodococcus, Corynebacterium or Gordonia). This offers the possibility of comparative studies that should help in deciphering the structure-function relationships and biosynthesis of these complex molecules in the future.

Interactions between dendritic cells (DCs) and Mycobacterium tuberculosis, the etiological agent of tuberculosis, most likely play a key role in anti-mycobacterial immunity. We have recently shown that M. tuberculosis binds to and infects DCs through ligation of the DC-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) and that M. tuberculosis mannose-capped lipoarabinomannan (ManLAM) inhibits binding of the bacilli to the lectin, suggesting that ManLAM might be a key DC-SIGN ligand. In the present study, we investigated the molecular basis of DC-SIGN ligation by LAM. Contrary to what was found for slow growing mycobacteria, such as M. tuberculosis and the vaccine strain Mycobacterium bovis bacillus Calmette-Guérin, our data demonstrate that the fast growing saprophytic species Mycobacterium smegmatis hardly binds to DC-SIGN. Consistent with the former finding, we show that M. smegmatis-derived lipoarabinomannan, which is capped by phosphoinositide residues (PILAM), exhibits a limited ability to inhibit M. tuberculosis binding to DC-SIGN. Moreover, using enzymatically demannosylated and chemically deacylated ManLAM molecules, we demonstrate that both the acyl chains on the ManLAM mannosylphosphatidylinositol anchor and the mannooligosaccharide caps play a critical role in DC-SIGN-ManLAM interaction. Finally, we report that DC-SIGN binds poorly to the PILAM and uncapped AraLAM-containing species Mycobacterium fortuitum and Mycobacterium chelonae, respectively. Interestingly, smooth colony-forming Mycobacterium avium, in which ManLAM is capped with single mannose residues, was also poorly recognized by the lectin. Altogether, our results provide molecular insight into the mechanisms of mycobacteria-DC-SIGN interaction, and suggest that DC-SIGN may act as a pattern recognition receptor and discriminate between Mycobacterium species through selective recognition of the mannose caps on LAM molecules.

The 26 S proteasome is a multisubunit proteolytic complex responsible for degrading eukaryotic proteins targeted by ubiquitin modification. Substrate recognition by the complex is presumed to be mediated by one or more common receptor(s) with affinity for multiubiquitin chains, especially those internally linked through lysine 48. We have identified previously a candidate for one such receptor from diverse species, designated here as Mcb1 for Multiubiquitin chain-binding protein, based on its ability to bind Lys48-linked multiubiquitin chains and its location within the 26 S proteasome complex. Even though Mcb1 is likely not the only receptor in yeast, it is necessary for conferring resistance to amino acid analogs and for degrading a subset of ubiquitin pathway substrates such as ubiquitin-Pro-beta-galactosidase (Ub-Pro-beta-gal) (van Nocker, S., Sadis, S., Rubin, D.M., Glickman, M., Fu, H., Coux, O., Wefes, I., Finley, D., and Vierstra, R. D. (1996) Mol. Cell. Biol. 16, 6020-28). To further define the role of Mcb1 in substrate recognition by the 26 S proteasome, a structure/function analysis of various deletion and site-directed mutants of yeast and Arabidopsis Mcb1 was performed. From these studies, we identified a single stretch of conserved hydrophobic amino acids (LAM/LALRL/V (ScMcb1 228-234 and At-Mcb1 226-232)) within the C-terminal half of each polypeptide that is necessary for interaction with Lys48-linked multiubiquitin chains. Unexpectedly, this domain was not essential for either Ub-Pro-beta-gal degradation or conferring resistance to amino acid analogs. The domain responsible for these two activities was mapped to a conserved region near the N terminus. Yeast and Arabidopsis Mcb1 derivatives containing an intact multiubiquitin-binding site but missing the N-terminal region failed to promote Ub-Pro-beta-gal degradation and even accentuated the sensitivity of the yeast delta mcb1 strain to amino acid analogs. This hypersensitivity was not caused by a gross defect in 26 S proteasome assembly as mutants missing either the N-terminal domain or the multiubiquitin chain-binding site could still associate with 26 S proteasome and generate a complex indistinguishable in size from that present in wild-type yeast. Together, these data indicate that residues near the N terminus, and not the multiubiquitin chain-binding site, are most critical for Mcb1 function in vivo.

Mycobacterium tuberculosis infection is accompanied by acute and chronic inflammatory infiltrates associated with necrotizing granulomas in lung tissue. The cellular infiltrate is characterized by inflammatory cells which include neutrophils, lymphocytes, and macrophages. In animal and in vitro models of mycobacterial infection, cytokines including tumor necrosis factor-alpha (TNF-alpha), interferon gamma (IFN-gamma), and interleukin-1 beta (IL-1 beta) participate in granulomatous inflammation. We hypothesized that interleukin-3, a potent chemoattractant for neutrophils and lymphocytes, could be released by activated alveolar macrophages after exposure to M. tuberculosis or its components and contribute to granulomatous lung inflammation. A quantitative immunoassay revealed that IL-8 protein release was significantly elevated in supernatants of macrophages and in lavage fluid obtained from patients with pulmonary tuberculosis compared to normal controls. In addition, Northern blots demonstrated striking up-regulation of IL-8 mRNA in macrophages from these patients. M. tuberculosis and its cell wall components lipoarabinomannan (LAM), lipomannan (LM), and phosphoinositolmannoside (PIM) stimulated IL-8 protein release and mRNA expression in vitro from alveolar macrophages, but deacylated LAM did not. Neutralizing antibodies to TNF-alpha and/or IL-1-alpha and beta blocked 83% of the stimulation. IL-8 synthesis and release is an early response of macrophages after phagocytosis of M. tuberculosis. Its production serves to attract both acute and chronic inflammatory cells of active infection and thus participates in the process of containment of the pathogen.

OBJECTIVE

To determine the efficacy of tenofovir disoproxil fumarate (TDF) in adults with chronic hepatitis B virus (HBV) infection who had previously failed lamivudine (LAM) and had significant viral replication (HBV DNA >10⁵ copies/ml if HBeAg positive,>> 10⁴ copies/ml if HBeAg negative) despite at least 24 weeks of treatment with adefovir dipivoxil (ADV).

METHODS

A prospective open-label study of TDF 300 mg daily. Patients receiving combination ADV/LAM prior to baseline were switched to TDF/LAM.

METHODS

Multiple tertiary referral centres.

METHODS

Sixty patients were enrolled. The median age was 48.5 years (range 21e80), 46 (77%) were male and 40 (67%) were HBeAg positive. Thirty-eight patients (63%) were switched from ADV to TDF, the remainder from ADV/LAM to TDF/LAM. At baseline, substitutions conferring resistance to LAM or ADV were present in 20 patients (33%) and 17 patients (28%), respectively. The median baseline viral load was 5.33 log₁₀ IU/ml (range 2.81-8.04). Patients initially treated with TDF monotherapy with persistent viral replication at or after 24 weeks were switched to TDF/LAM. The main outcome measures were change in HBV viral load from baseline and percentage of patients achieving an undetectable viral load (<15 IU/ml).

RESULTS

Results are reported at 96 weeks of treatment. One patient discontinued TDF at 10 days due to rash. The time-weighted change in viral load from baseline to week 12 was -2.19 log10 IU/ml overall. The median change in HBV DNA from baseline to weeks 12, 24, 48 and 96 was -2.86, -3.23, -3.75 and -4.03 log₁₀ IU/ml, respectively. At 48 and 96 weeks, 27/59 (46%) and 38/59 (64%) patients achieved a HBV DNA <15 IU/ml. The response was independent of baseline LAM therapy or mutations conferring ADV resistance.

CONCLUSIONS

In heavily pretreated patients with a high rate of genotypic resistance, TDF retains significant activity against HBV although this appears diminished in comparison with studies of naïve patients.

OBJECTIVE

Lymphangioleiomyomatosis (LAM), a disease affecting women and causing cystic lung lesions, and, in some instances, leading to respiratory failure and death, appears to be exacerbated by estrogens. Hence, hormonal therapy with progesterone is frequently employed; however, efficacy has not been demonstrated. Our aim was to determine whether progesterone administration slowed the decline in lung function in LAM.

METHODS

Retrospective study.

METHODS

National Institutes of Health, Bethesda, MD.

METHODS

The study population comprised 348 patients with LAM participating in a longitudinal research protocol. Declines in diffusion capacity of the lung for carbon monoxide (Dlco) and FEV(1) were measured in 275 patients observed for approximately 4 years. The declines in Dlco and FEV(1) of patients treated with progesterone, po (n = 67) or IM (n = 72), were compared with those of untreated patients (n = 136).

RESULTS

Overall yearly rates of decline in Dlco and FEV(1) were 2.4 +/- 0.4% predicted (0.69 +/- 0.07 mL/min/mm Hg) and 1.7 +/- 0.4% predicted (75 +/- 9 mL), respectively (mean +/- SEM). The most significant predictors of functional decline were initial lung function and age. After adjusting for initial FEV(1), age, and duration of disease, patients treated with IM progesterone tended to have lower rates of decline in FEV(1) than patients treated po (1.9 +/- 0.6% predicted vs 3.2 +/- 0.8% predicted, respectively; p = 0.081). However, there was no significant difference in rates of decline in FEV(1) between patients treated with IM progesterone and untreated patients (1.9 +/- 0.6% predicted vs 0.8 +/- 0.5% predicted, respectively; p = 0.520), and patients treated with po progesterone and untreated patients (3.2 +/- 0.8% predicted vs 0.8 +/- 0.5% predicted, respectively; p = 0.064). After adjusting for initial Dlco, rates of decline in Dlco were significantly higher in patients treated with po progesterone (3.6 +/- 0.7% predicted, p = 0.002) and IM progesterone (2.8 +/- 0.5% predicted, p = 0.022) than in untreated patients (1.6 +/- 0.6% predicted).

CONCLUSIONS

Within the limitations of a retrospective study, our data suggest that progesterone therapy does not slow the decline in lung function in LAM.

We show here that purified lipoarabinomannan (LAM) from Mycobacterium tuberculosis can cause the release of tumour necrosis factor (TNF) in vitro from human blood monocytes and activated mouse peritoneal macrophages, and the production of TNF in vivo in mice pretreated with Propionibacterium acnes, with a potency comparable to that of lipopolysaccharide (LPS) from Gram negative bacteria. Like LPS, LAM binds to polymyxin B. We confirmed that its activity was distinct from any contaminating LPS and was associated with the antigenic activity by affinity chromatography, using a monoclonal antibody specific for LAM. Treatment with dilute alkali greatly diminished the TNF-inducing activity, suggesting that omicron-acyl groups may be involved. When LAM was fractionated by electrophoresis on SDS-Page and blotted on nitrocellulose, most TNF-inducing capacity coincided with the bulk of the LAM, as estimated by molecular weight and antigenic activity. This modification of the Western blotting technique may be generally useful for the study of macrophage-triggering molecules. The ability of LAM to cause the release of TNF may be responsible for some of the characteristics of tuberculosis, such as fever, weight loss, raised acute phase reactants and necrosis that can be mediated by this cytokine.

The extremely well-conserved La motif (LAM), in synergy with the immediately following RNA recognition motif (RRM), allows direct binding of the (genuine) La autoantigen to RNA polymerase III primary transcripts. This motif is not only found on La homologs, but also on La-related proteins (LARPs) of unrelated function. LARPs are widely found amongst eukaryotes and, although poorly characterized, appear to be RNA-binding proteins fulfilling crucial cellular functions. We searched the fully sequenced genomes of 83 eukaryotic species scattered along the tree of life for the presence of LAM-containing proteins. We observed that these proteins are absent from archaea and present in all eukaryotes (except protists from the Plasmodium genus), strongly suggesting that the LAM is an ancestral motif that emerged early after the archaea-eukarya radiation. A complete evolutionary and structural analysis of these proteins resulted in their classification into five families: the genuine La homologs and four LARP families. Unexpectedly, in each family a conserved domain representing either a classical RRM or an RRM-like motif immediately follows the LAM of most proteins. An evolutionary analysis of the LAM-RRM/RRM-L regions shows that these motifs co-evolved and should be used as a single entity to define the functional region of interaction of LARPs with their substrates. We also found two extremely well conserved motifs, named LSA and DM15, shared by LARP6 and LARP1 family members, respectively. We suggest that members of the same family are functional homologs and/or share a common molecular mode of action on different RNA baits.

The results of this study show that lipoarabinomannans (LAM) isolated from a virulent strain and from an avirulent strain of Mycobacterium tuberculosis, which have recently been shown to differ markedly in terms of the structures of their nonreducing termini, also differ markedly in the capacity to induce the secretion of tumor necrosis factor from murine macrophages. It was found that LAM from the avirulent H37Ra strain was 100-fold more potent at inducing tumor necrosis factor secretion than LAM from the virulent Erdman strain, thus leading us to hypothesize that the structure of LAM from a given mycobacterial isolate may directly influence its ability to elicit, or avoid, cytokine-mediated mechanisms of host resistance.

BACKGROUND

Effective tuberculosis (TB) control in HIV-prevalent settings is hindered by absence of accurate, rapid TB diagnostic tests. We evaluated the accuracy of a urine lipoarabinomannan (LAM) test for TB diagnosis in South Africa.

METHODS

Hospitalized adults with signs and/or symptoms of active TB were enrolled. Sputum smear microscopy and mycobacterial culture, mycobacterial blood culture, and HIV testing were performed. A spot urine specimen was tested for LAM.

RESULTS

Four hundred ninety nine participants were enrolled; 422 (84.6%) were HIV infected. In microbiologically confirmed TB patients, the LAM test was positive in 114 of 193 [sensitivity 59%, (95% confidence interval: 52 to 66)], including 112 of 167 [67% (59 to 74)] who were HIV infected. Among individuals classified as "not TB", the LAM test was negative in 117 of 122 [specificity 96% (91 to 99)], including 83 of 88 [94% (87 to 98)] who were HIV infected. In confirmed TB patients, the LAM test was more sensitive than sputum smear microscopy (42%, 82 of 193, P < 0.001) and detected 56% (62 of 111) of those who were sputum smear negative. HIV infection [adjusted odds ratio (AOR 13.4)], mycobacteremia (AOR 3.21), and positive sputum smear (AOR 2.42) were risk factors for a positive LAM test.

CONCLUSIONS

The urine LAM test detected a subset of HIV-infected patients with severe TB in whom sputum smear microscopy had suboptimal sensitivity. The combination of urine LAM testing and sputum smear microscopy is attractive for use in settings with high HIV burden.

OBJECTIVE

To evaluate comprehensively the characteristics of lymphangioleiomyomatosis (LAM), with emphasis on the application of imaging and immunohistochemical methods.

METHODS

Prospective study.

METHODS

Thirty-five female subjects with LAM.

METHODS

Clinical Center, National Institutes of Health.

METHODS

BAL, pulmonary function test, ventilation/perfusion lung scans, CT of the chest and abdomen, ultrasonography of abdomen, and immunohistochemical study of lung biopsy specimens.

RESULTS

Most patients had exertional dyspnea (83%) and pneumothorax (69%). BAL did not show diagnostic changes. The most common abnormalities on pulmonary function tests were decreased diffusing capacity of carbon monoxide (83%), hypoxemia (57%), and airway obstruction (51%). Bronchodilator response was found in 26% of patients. CT, which is almost pathognomonic, showed numerous thin-walled cysts throughout both lungs in all patients. Thirty-four patients (97%) had abnormal ventilation and/or perfusion lung scans. An unusual "speckling" pattern was observed on ventilation scans of 74% of patients. Common extrapulmonary features were retroperitoneal adenopathy (77%) and renal angiomyolipomas (60%). The percentage of abnormal smooth muscle cells (LAM cells), reactive with HMB45, varied from 17 to 67% in 10 lung biopsy specimens.

CONCLUSIONS

Improved diagnostic methods have defined the abnormalities in patients with pulmonary LAM and increased the potential for early recognition and treatment of this disorder. Patients with LAM should be evaluated for bronchodilator responsiveness and may benefit from a trial of bronchodilators.

BACKGROUND

The accurate diagnosis of TB in HIV-infected patients, particularly with advanced immunosuppression, is difficult. Recent studies indicate that a lipoarabinomannan (LAM) assay (Clearview-TB(R)-ELISA) may have some utility for the diagnosis of TB in HIV-infected patients; however, the precise subgroup that may benefit from this technology requires clarification. The utility of LAM in sputum samples has, hitherto, not been evaluated.

METHODS

LAM was measured in sputum and urine samples obtained from 500 consecutively recruited ambulant patients, with suspected TB, from 2 primary care clinics in South Africa. Culture positivity for M. tuberculosis was used as the reference standard for TB diagnosis.

RESULTS

Of 440 evaluable patients 120/387 (31%) were HIV-infected. Urine-LAM positivity was associated with HIV positivity (p = 0.007) and test sensitivity, although low, was significantly higher in HIV-infected compared to uninfected patients (21% versus 6%; p<0.001), and also in HIV-infected participants with a CD4 <200 versus >200 cells/mm(3) (37% versus 0%; p = 0.003). Urine-LAM remained highly specific in all 3 subgroups (95%-100%). 25% of smear-negative but culture-positive HIV-infected patients with a CD4 <200 cells/mm(3) were positive for urine-LAM. Sputum-LAM had good sensitivity (86%) but poor specificity (15%) likely due to test cross-reactivity with several mouth-residing organisms including actinomycetes and nocardia species.

CONCLUSIONS

These preliminary data indicate that in a high burden primary care setting the diagnostic usefulness of urine-LAM is limited, as a rule-in test, to a specific patient subgroup i.e. smear-negative HIV-infected TB patients with a CD4 count <200 cells/mm(3), who would otherwise have required further investigation. However, even in this group sensitivity was modest. Future and adequately powered studies in a primary care setting should now specifically target patients with suspected TB who have advanced HIV infection.

tpo mutations, located at 74 min on the genetic map, rendered Escherichia coli K-12 resistant to TP1, a phage which can use either the OmpF protein or the LamB protein as its receptor. tpo mutants synthesized decreased amounts of OmpF and LamB proteins but increased amounts of the OmpC product, another outer membrane protein. The effect of the tpo mutations in lam B gene expression was transcriptional. It is one facet of the following effect on the maltose regulon: strong decreases in the syntheses of the LamB protein and the periplasmic MalE protein occurred when the regulon was uninduced; a lesser decrease occurred in the syntheses of the LamB protein the MalE protein, and the cytoplasmic MalQ protein (amylomaltase) when the regulon was induced. The tpo mutants were found to be phenotypically identical to the perA mutant recently described by Wanner et al. (J. Bacteriol. 140:229--239, 1979) and to some of the ompB mutants described by Verhoef et al. (Mol. Gen. Genet. 169:137--146, 1979). Mapping and complementation analysis suggested that these three types of mutations belong to the same cistron. Our results bring to at least four the number of clearly distinct phenotypes which can result from mutations at, or close to, ompB, a locus which appears increasingly complex.

BACKGROUND

Tuberous sclerosis (TSC) related tumors are characterized by constitutively activated mTOR signaling due to mutations in TSC1 or TSC2.

METHODS

We completed a phase 2 multicenter trial to evaluate the efficacy and tolerability of the mTOR inhibitor, sirolimus, for the treatment of kidney angiomyolipomas.

RESULTS

36 adults with TSC or TSC/LAM were enrolled and started on daily sirolimus. The overall response rate was 44.4% (95% confidence intervals [CI] 28 to 61); 16/36 had a partial response. The remainder had stable disease (47.2%, 17/36), or were unevaluable (8.3%, 3/36). The mean decrease in kidney tumor size (sum of the longest diameters [sum LD]) was 29.9% (95% CI, 22 to 37; n = 28 at week 52). Drug related grade 1-2 toxicities that occurred with a frequency of >20% included: stomatitis, hypertriglyceridemia, hypercholesterolemia, bone marrow suppression (anemia, mild neutropenia, leucopenia), proteinuria, and joint pain. There were three drug related grade 3 events: lymphopenia, headache, weight gain. Kidney angiomyolipomas regrew when sirolimus was discontinued but responses tended to persist if treatment was continued after week 52. We observed regression of brain tumors (SEGAs) in 7/11 cases (26% mean decrease in diameter), regression of liver angiomyolipomas in 4/5 cases (32.1% mean decrease in longest diameter), subjective improvement in facial angiofibromas in 57%, and stable lung function in women with TSC/LAM (n = 15). A correlative biomarker study showed that serum VEGF-D levels are elevated at baseline, decrease with sirolimus treatment, and correlate with kidney angiomyolipoma size (Spearman correlation coefficient 0.54, p = 0.001, at baseline).

CONCLUSIONS

Sirolimus treatment for 52 weeks induced regression of kidney angiomyolipomas, SEGAs, and liver angiomyolipomas. Serum VEGF-D may be a useful biomarker for monitoring kidney angiomyolipoma size. Future studies are needed to determine benefits and risks of longer duration treatment in adults and children with TSC.

BACKGROUND

Clinicaltrials.gov NCT00126672.

Pulmonary lymphangioleiomyomatosis (LAM) is a rare disorder of unknown cause characterized by peribronchial, perivascular, and perilymphatic proliferation of abnormal smooth muscle cells leading to cystic lesions. The hypothesis of hormonal dependence and the effectiveness of hormonal therapy have not yet been demonstrated conclusively, and the prevalence of extrathoracic manifestations and the survival of patients with LAM are somewhat contradictory. A multicentric retrospective study was conducted in an attempt to describe better the initial features, the diagnostic procedures, the associated lesions, and, above all, the management and course of LAM in a large homogeneous series of 69 stringently selected patients, with a majority of cases diagnosed since 1990. The aim of the study, based on a review of the literature, also was to provide a comprehensive view of this uncommon disease. The clinical features were in keeping with previous studies, but we found that exertional dyspnea and pneumothorax were the most common features, and chylous involvement was less frequent. LAM was diagnosed after menopause in about 10% of cases. The onset of LAM occurred during pregnancy in 20% of cases, and a clear exacerbation of LAM was observed in 14% of cases during pregnancy. Pulmonary LAM was diagnosed on lung histopathology in 83% of cases, but renal angiomyolipoma, observed in 32% of our patients, may be a useful diagnostic criterion when associated with typical multiple cysts on chest CT scan or with chylous effusion. Chest CT scan was more informative than chest X-ray (normal in 9% of cases), and may be indicated in spontaneous pneumothorax or renal angiomyolipoma in women of childbearing age. About 40% of the patients had a normal initial spirometry, while an obstructive ventilatory defect (44%), a restrictive ventilatory defect (23%), was observed in other patients. Initial diffusing capacity for carbon monoxide was frequently decreased (82%). Hormonal therapy was administered in 57 patients, but a clear>> or = 15% improvement of FEV1 was observed in only 4 evaluable patients, treated with tamoxifen and progestogens (n = 2), progestogen (n = 1), and oophorectomy (n = 1). Probably 1 of the most urgent needs for clinical research in LAM is to test the currently available hormonal treatments in the context of international multicenter prospective controlled studies. Pleurodesis was performed in 40 patients. Lung transplantation was performed in 13 patients, 7.8 +/- 5.2 years after onset of LAM, in whom the mean FEV1 was 0.57 +/- 0.15 L. After a follow-up of 2.3 +/- 2.2 years, 9 patients were alive. Mean follow-up from onset of disease to either death or closing date was 8.2 +/- 6.3 years. Overall survival was better than usually reported in LAM, and Kaplan-Meier plot showed survival probabilities of 91% after 5 years, 79% after 10 years, and 71% after 15 years of disease duration.

BACKGROUND

Sweet potato (Ipomoea batatas L. [Lam.]) ranks among the top six most important food crops in the world. It is widely grown throughout the world with high and stable yield, strong adaptability, rich nutrient content, and multiple uses. However, little is known about the molecular biology of this important non-model organism due to lack of genomic resources. Hence, studies based on high-throughput sequencing technologies are needed to get a comprehensive and integrated genomic resource and better understanding of gene expression patterns in different tissues and at various developmental stages.

RESULTS

Illumina paired-end (PE) RNA-Sequencing was performed, and generated 48.7 million of 75 bp PE reads. These reads were de novo assembled into 128,052 transcripts (≥ 100 bp), which correspond to 41.1 million base pairs, by using a combined assembly strategy. Transcripts were annotated by Blast2GO and 51,763 transcripts got BLASTX hits, in which 39,677 transcripts have GO terms and 14,117 have ECs that are associated with 147 KEGG pathways. Furthermore, transcriptome differences of seven tissues were analyzed by using Illumina digital gene expression (DGE) tag profiling and numerous differentially and specifically expressed transcripts were identified. Moreover, the expression characteristics of genes involved in viral genomes, starch metabolism and potential stress tolerance and insect resistance were also identified.

CONCLUSIONS

The combined de novo transcriptome assembly strategy can be applied to other organisms whose reference genomes are not available. The data provided here represent the most comprehensive and integrated genomic resources for cloning and identifying genes of interest in sweet potato. Characterization of sweet potato transcriptome provides an effective tool for better understanding the molecular mechanisms of cellular processes including development of leaves and storage roots, tissue-specific gene expression, potential biotic and abiotic stress response in sweet potato.

Lack of point-of-care tests for tuberculosis (TB) result in diagnostic delay, and increased mortality and healthcare-related costs. The urine Determine(TM) TB-LAM point-of-care strip-test was evaluated in 335 prospectively-recruited hospitalised patients with suspected TB-HIV co-infection (group 1) and from 88 HIV-infected hospitalised patients with non-TB diagnoses (group 2). Cut-off point-specific analyses were performed using: 1) a microbiological reference standard (culture positive versus negative); and 2) a composite reference standard (exclusion of patients with clinical-TB from the culture-negative group). Using the microbiological reference and the manufacturer-recommended grade-1 cut-off point, LAM sensitivity and specificity was 66% (95% CI 57-74%). By contrast, using the composite reference sensitivity was 60% (95% CI 53-67%) and specificity improved to 96% (95% CI 89-100%) (p=0.001). The same pattern was seen when the grade-2 cut-off point was used (specificity 75% versus 96%; p=0.01). In group two patients specificity was poor using the grade-1 cut-off point, but improved significantly when the grade-2 cut-off point was used (90% versus 99%; p=0.009). The grade-2 cut-off point also offered superior inter-reader reliability (p=0.002). Sensitivity was highest in those with a CD4 <200 cells per mL. LAM combined with smear-microscopy was able to rule-in TB in 71% of Mycobacterium tuberculosis culture-positive patients. This preliminary study indicates that the LAM strip-test may be a potentially useful rapid rule-in test for TB in hospitalised patients with advanced immunosuppression. The grade 2, but not the manufacturer-recommended grade 1 cut-off point, offered superior rule-in utility and inter-reader reliability. Larger studies to evaluate cut-off points and diagnostic accuracy are urgently required.

A central feature of host defence is the ability of leukocytes to enter tissues in response to immune or inflammatory stimuli. The leukocyte adhesion molecule-1 (LAM-1) regulates the migration of human leukocytes by mediating the binding both of lymphocytes to high endothelial venules of peripheral lymph nodes and of neutrophils to endothelium at inflammatory sites. As lymphocytes and neutrophils express the same LAM-1 protein, it is not clear how lineage-specific differences in leukocyte migration are controlled. We now report that the affinity of LAM-1 for a carbohydrate-based ligand, PPME, is dramatically increased following lymphocyte and neutrophil activation by lineage-specific stimuli. In addition, activation of lymphocytes by physiological stimuli enhanced LAM-1-dependent binding to high endothelial venules. Thus, transient changes in LAM-1 affinity after leukocyte stimulation probably directly influence leukocyte migration.

The dimannoside (PIM2) and hexamannoside (PIM6) phosphatidyl-myo-inositol mannosides are the two most abundant classes of PIM found in Mycobacterium bovis bacillus Calmette Guérin, Mycobacterium tuberculosis H37Rv, and Mycobacterium smegmatis 607. Recently, these long known molecules received a renewed interest due to the fact that PIM2 constitute the anchor motif of an important constituent of the mycobacterial cell wall, the lipoarabinomannans (LAM), and that both LAM (phosphoinositol-capped LAM) and PIM are agonists of Toll-like receptor 2 (TLR2), a pattern recognition receptor involved in innate immunity. Due to the biological importance of these molecules, the chemical structure of PIM was revisited. The structure of PIM2 was recently published (Gilleron, M., Ronet, C., Mempel, M., Monsarrat, B., Gachelin, G., and Puzo, G. (2001) J. Biol. Chem. 276, 34896-34904). Here we report the purification and molecular characterization of PIM6 in their native form. For the first time, four acyl forms of this molecule have been purified, using hydrophobic interaction chromatography. Mono- to tetra-acylated molecules were identified in M. bovis bacillus Calmette Guérin, M. tuberculosis H37Rv, and M. smegmatis 607 using a sophisticated combination of analytical tools, including matrix-assisted laser desorption/ionization-time of flight-mass spectrometry and two-dimensional homo- and heteronuclear NMR spectroscopy. These experiments revealed that the major acyl forms are similar to the ones described for PIM2. Finally, we show that PIM6, like PIM2, activate primary macrophages to secrete TNF-alpha through TLR2, irrespective of their acylation pattern, and that they signal through the adaptor MyD88.