Role of IS6110 uniplex PCR in the diagnosis of tuberculous meningitis: experience at a tertiary neurocentre.

SETTING: Tuberculous meningitis (TBM) is the commonest form of neurotuberculosis in the Indian subcontinent. Rapid laboratory confirmation of TBM is important for the institution of early treatment and to avoid associated morbidity and mortality. The polymerase chain reaction (PCR) is the most widely applied alternative rapid diagnostic technique for TBM. OBJECTIVE: To evaluate the efficacy of an in-house developed IS6110 uniplex PCR (uPCR) in the diagnosis of TBM. DESIGN: A prospective, blinded study was conducted in a large sample base of 677 cerebrospinal fluid samples from 677 patients with clinically suspected TBM. RESULTS: All culture-positive samples (n = 136) were positive (100%) by the PCR assay. The assay was found to be positive in 70% (n = 541) of the samples with a clinical diagnosis of TBM. The assay had an observed sensitivity of 76.37% (negative predictive value 59.90%) and a specificity of 89.18% (positive predictive value 94.69%). A diagnostic accuracy of 80% (kappa 0.57) was seen in patients with a clinical diagnosis of TBM. Statistical significance was observed, as patients with a clinical diagnosis of TBM were found to be 9.38 times more likely to be PCR-positive (OR 9.38, chi2 = 149.94, P < 0.001). CONCLUSION: The performance of the in-house IS6110 uPCR assay merits its use as a sensitive and specific tool for the rapid diagnosis of TBM.     

Comparative evaluation of BACTEC 460TB system and Lowenstein-Jensen medium for the isolation of M. tuberculosis from cerebrospinal fluid samples of tuberculous meningitis patients

PURPOSE: To evaluate the role of the radiometric BACTEC 460TB system and the conventional Lowenstein-Jensen (LJ) medium for isolation of M. tuberculosis from cerebrospinal fluid (CSF) samples of tuberculous meningitis (TBM) patients. METHODS: CSF specimens (n=2325) from suspected TBM patients were processed for isolation of mycobacteria by inoculating BACTEC 12B medium and the LJ medium. The isolation of mycobacteria in both media was confirmed by microscopy and biochemical identification. Drug sensitivity testing for the anti-TB drugs was carried out by BACTEC radiometric method. RESULTS: Among the total 2325 CSF specimens processed by both methods, M. tuberculosis was isolated from 256 specimens. The isolation rates were 93% and 39% for the BACTEC system and LJ medium respectively. Both the media supported growth in 32% of the culture-positive specimens. BACTEC system alone yielded growth in 61% and LJ alone in 7%, of the culture-positive specimens. Among 205 isolates tested for drug susceptibility 81% were sensitive to all the drugs tested and 19% were resistant. CONCLUSIONS: The BACTEC 460TB system provides a highly sensitive and rapid tool for the isolation and drug susceptibility testing of M. tuberculosis, from CSF of TBM patients. Use of a solid medium in conjunction with the BACTEC 12B medium is essential for optimal recovery for M. tuberculosis from CSF specimens.     

Postoperative monitoring of myocardial oxygen tension: Experience in 51 coronary artery bypass patients

Following a preliminary feasibility report, polarographic monitoring of myocardial tissue O₂ tension (PmO₂) in 51 coronary bypass patients has been accomplished. In this context, the influence of rapid atrial pacing (RAP), O₂ inhalation, and intra-aortic balloon assistance (IAB) was statistically analyzed using Wilcoxon sign-rank and Student's t-tests. Electrodes were implanted in revascularized and nonrevascularized areas for comparison (24.0 ± 1.1; and 26.3 ± 1.8 mmHg PmO₂, p, not significant). Increasing myocardial O₂ demand with RAP caused a 6% PmO₂ drop (p<0.01). A 70% O₂ inhalation increased Pmo₂ by 30% (p<0.01). In 5 cases the benefit of IAB was confirmed by a 41% increase in Pmo₂ (p = 0.02). These data support the clinical usefulness of polarographic PmO₂ as a measure of regional myocardial oxygenation. In addition to early recognition of intraoperative or postoperative graft failure previously reported, the efficacy of various therapeutic interventions can be more precisely determined.     

Lipid and glycolipid antigens of CD1d-restricted natural killer T cells

In spite of their relatively limited antigen receptor repertoire, CD1d-restricted NKT cells recognize a surprisingly diverse range of lipid and glycolipid antigens. Recent studies of natural and synthetic CD1d-presented antigens provide an increasingly detailed picture of how the specific structural features of these lipids and glycolipids influence their ability to be presented to NKT cells and stimulate their diverse immunologic functions. Particularly for synthetic analogues of α-galactosylceramides which have been the focus of intense recent investigation, it is becoming clear that the design of glycolipid antigens with the ability to precisely control the specific immunologic activities of NKT cells is likely to be feasible. The emerging details of the mechanisms underlying the structure–activity relationship of NKT cell antigens will assist greatly in the design and production of immunomodulatory agents for the precise manipulation of NKT cells and the many other components of the immune system that they influence.     

Antifungal and antioxidant activities of organic and aqueous extracts of Annona squamosa Linn. leaves

An increasing demand for natural additives has shifted the attention from synthetic to natural antioxidants and antifungal agents. This study was carried out to evaluate the antifungal and antioxidant activities of methanol, chloroform, and aqueous extracts of Annona squamosa Linn. leaves. The antifungal activities of all extracts of A. squamosa leaves against five different strains of fungi (Alternaria alternata, Candida albicans, Fusarium solani, Microsporum canis, and Aspergillus niger) were evaluated by the agar well diffusion method and the minimum inhibitory concentration of each extract was assessed by antifungal susceptibility using the broth microdilution method. The antioxidant potential of each extract was determined by free radicals (1,1-diphenyl-2-picrylhydrazyl, nitric oxide, and hydrogen peroxide) scavenging activity and reducing power property of A. squamosa leaves. Both organic and aqueous extracts were found to express dose-dependent inhibition against all tested fungi strains in both agar well diffusion and broth dilution methods. The free radical scavenging activity and reducing power property of all extracts were found to be concentration dependent, with the methanol extract exhibiting higher antioxidant activity than the chloroform extract, which was more effective than the aqueous extract of A. squamosa leaves. Results of phytochemical analysis of extracts showed the presence of glycosides, saponins, tannins, flavonoids, phenols, etc. The results obtained from in vitro studies of antifungal and antioxidant activities clearly suggest that the methanol, chloroform, and aqueous extracts of A. squamosa leaves possess antifungal and antioxidant activity.     

Preliminary Phytochemical Screening and Antimicrobial Studies of Lantana indica Roxb

The aim of the present study was to investigate the antimicrobial and preliminary phytochemical properties of Lantana indica Roxb. The aqueous and organic solvent (ethyl acetate and methanol) extracts from the leaves of Lantana indica (Verbenaceae) were tested against Staphylococcus aureus, Bacillus subtilis, Steptococcus pyrogens, Escherichia coli, Proteus vulgaris, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, Aspergillus niger and Candida albicans by agar well diffusion method. The results showed promising antibacterial activity against the tested bacteria. Among these, methanol and aqueous extracts were found to possess a more potent inhibitory effect when compared to the ethyl acetate extract. Preliminary phytochemical analysis of extracts revealed the presence of antimicrobial compounds such as carbohydrates, proteins, tannins and flavonoidal glycosides. The result of this study validates the use of methanol and aqueous extract of this species in ethnomedicine, favouring the isolation of antibacterial agents from the leaf extract of Lantana indica.     

Lysine requirements of healthy adult Indian subjects receiving long-term feeding,measured with a 24-h indicator amino acid oxidation and balance technique

BACKGROUND: The mean lysine requirement of healthy Indian subjects was estimated from short-term experimental diet periods to be 29 mg x kg(-1) x d(-1), which is higher than the 1985 FAO/WHO/UNU upper requirement of 12 mg x kg(-1) x d(-1). OBJECTIVE: Our objective was to confirm our proposed requirement of 29 mg x kg(-1) x d(-1) by extending the diet period to 21 d and by using 4 test lysine intakes (12, 20, 28, and 36 mg x kg(-1) x d(-1)) and a 24-h indicator amino acid oxidation and balance approach. DESIGN: During two 21-d diet periods, 18 healthy Indian men were randomly assigned to receive 12 and 28 or 20 and 36 mg lysine x kg(-1) x d(-1) as part of an L-amino acid diet. At 1800 on days 6 and 20, [(13)C]leucine was infused over 24 h to assess leucine oxidation and daily leucine balance at each test intake. RESULTS: Leucine oxidation, balance, and flux did not differ significantly between days 7 and 21. Twenty-four-hour leucine oxidation was lower at lysine intakes of 28 and 36 mg than at 12 and 20 mg. Leucine balances at lysine intakes of 12 and 20 mg were negative and significantly less than equilibrium (P < 0.01) and lower (P < 0.02) than balances at 28 and 36 mg lysine. Two-phase regression analysis indicated a breakpoint at 31 mg lysine x kg(-1) x d(-1) in the relation between lysine intake and 24-h leucine oxidation and balance. CONCLUSIONS: Full adaptation to a low lysine intake occurs within 7 d. The previously proposed tentative mean lysine requirement for Western subjects of 30 mg x kg(-1) x d(-1) is confirmed for healthy Indian adults.