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L Raju

Publications and source records attributed to L Raju.

18 recordsLinked to original sources
PubMed2000

Signal sequence and alanine-rich region of streptococcal protein antigen A of Streptococcus sobrinus can direct localization of alkaline phosphatase to the periplasm of Escherichia coli.

Streptococcal protein antigen A (SpaA) of Streptococcus sobrinus is expressed on the surface of cells and extracellularly. TnphoA which lacks signals for transcription and membrane transport of Escherichia coli alkaline phosphatase was used to analyze the sequences necessary for transport of a SpaA/PhoA fusion protein across the cytoplasmic membrane to the periplasm of E. coli cells. Of 15 alkaline phosphatase-producing isolates analyzed, all were found to localize more than 85% of the SpaA/PhoA hybrid protein to the periplasm of E. coli cells. From DNA sequence analysis, all were found to have TnphoA inserted into an identical site. The insertion site of TnphoA was downstream from the coding sequence that generates four tandemly repeated alanine-rich sequences of 82 amino acid residues. These results suggest that in addition to the signal sequence, mature protein sequences containing alanine-rich repeat sequences may play a role in the export of the SpaA protein across a bacterial membrane.

Alanine↗
PubMed1992

Incarceration of existing inguinal hernia as a complication of pulmonary function testing.

Pulmonary function testing (PFT) has not been listed as a risk for development of incarceration in an existing inguinal hernia. We report two patients who developed this complication after routine preoperative PFT. We also present data of our retrospective review of eight patients with inguinal hernia who were referred for preoperative PFT. Two out of eight patients suffered incarceration of an existing inguinal hernia. We found no significant difference in mean age, weight, smoking habits, number of forced expiratory maneuvers, time of sustained forced expiratory maneuver, or any PFT data between the groups with and without incarceration. Thus, incarceration of inguinal hernia could not have been predicted prior to PFT and was not related to other factors such as obesity or more severe airway obstruction.

Aged↗
PubMed1990

Nontemplated bases at the 5' ends of Tacaribe virus mRNAs.

Centrifugation of Tacaribe arenavirus-infected cell extracts on CsCl density gradients was used to separate genomes and antigenomes, which band at 1.31 g/ml as nucleocapsids, from mRNAs which pellet. Primer extensions on the banded RNAs showed that the 5' ends of the genomes and antigenomes were unique, whereas primer extensions on the mRNAs showed that their 5' ends were heterogenous in length, extending 0-4 bases beyond the 3' ends of the templates for their synthesis. This suggests that arenavirus mRNAs may initiate by a cap-snatching mechanism, somewhat similar to influenza viruses and bunyaviruses. We also found an extra G residue at the 5' end of the genome RNA, which was not predicted according to current models. This is now the third time that the unexpected G residue has been found at the 5' end of arenavirus genomes.

Animals↗
PubMed1989

The translational requirement for complete La Crosse virus mRNA synthesis is cell-type dependent.

The translational requirement to prevent premature termination during La Crosse virus S mRNA synthesis was found to be cell-type dependent. This requirement was present in the BHK, HEL, and Vero cell lines we examined, but not in C6/36 mosquito cells. The cell-dependent translational requirement could be reproduced in vitro by using either cell extracts or purified virions of BHK and C6/36 cells. In the BHK reactions, the polymerase terminated predominantly at nucleotide 175 in the absence of concurrent translation and required translation to read through this position. In the C6/36 reactions, however, the polymerase reads through nucleotide 175 efficiently independent of translation. Reconstitution studies suggested that the translational requirement was due to a factor(s) present in BHK, but not in C6/36, cells.

Animals↗
PubMed1988

Elevated histamine and tryptase levels in smokers' bronchoalveolar lavage fluid. Do lung mast cells contribute to smokers' emphysema?

Human lung mast cells have been reported recently to contain small amounts of the elastolytic protease present in the neutrophil and implicated in the pathogenesis of alveolar wall destruction in emphysema. Since mast cells are numerous within alveolar walls, release of inflammatory mediators (and possibly elastase) by cigarette smoking could contribute to alveolar injury in this disease. We therefore examined bronchoalveolar lavage (BAL) fluid for the mast cell granule constituents histamine and tryptase. The results, while not conclusive, supported the possibility that cigarette smoking increases secretion of histamine releasing activity by alveolar macrophages with subsequent degranulation of local mast cells. Mast cell discharge of inflammatory mediators (including neutrophil chemotactic factors and perhaps the elastolytic protease) could then participate in the destruction of alveolar walls.

Adult↗
PubMed1988

Pneumonia in the elderly: a review.

Elderly persons are at increased risk of acquiring pneumonia. Morbidity and mortality rates from pneumonia are also higher. Clinical manifestations of pneumonia in the elderly are frequently very subtle; however, a high index of suspicion will induce the physician to obtain a chest roentgenogram. A new lung infiltrate will confirm the diagnosis. Although the Gram's stain of a sputum smear is most helpful in the initial selection of a specific antibiotic, a good quality sputum is not usually available in the elderly, and empiric therapy reduces the morbidity and mortality from pneumonia.

Aged↗
PubMed1983

The role of oxidative processes in emphysema.

Elastase/elastase inhibitor imbalance in the lung has been implicated in the pathogenesis of pulmonary emphysema. In light of this, it may be significant that the activity of two major elastase inhibitors, alpha 1-proteinase inhibitor (alpha 1-antitrypsin, alpha 1Pi) and bronchial mucous proteinase inhibitor, can be decreased by oxidizing agents. The effect can be observed with ozone, substances present in cigarette smoke, and oxygen metabolites generated by lung macrophages as well as peroxidative systems released by other phagocytic cells. Thus alpha 1Pi recovered from lung washings of cigarette smokers has only half the predicted normal activity per mg inhibitor and contains 4 moles of methionine sulfoxide (oxidized methionine) per mole of inactive inhibitor. By contrast, alpha 1Pi purified from nonsmokers' lung washings is fully active and contains only native methionine. At the same time, lung washes from some smokers show significantly greater hydrolytic activity against a specific synthetic elastase substrate than do lung washes of nonsmokers. These findings suggest that some smokers may develop an acquired imbalance between elastase and elastase inhibitor in their lungs, favoring activity of the enzyme. In addition to the potential effect of cigarette smoking on lung elastase/elastase inhibitor balance, smoking also may interfere with elastin repair mechanisms. Specifically, acidic water-soluble gas phase components of cigarette smoke prevent synthesis of desmosine cross-links during elastinogenesis in vitro. This report will attempt to correlate the foregoing information on biochemical changes in the lung induced by cigarette smoking with the development of emphysema in the smoker.

Drug Synergism↗
PubMed1983

Levels of elastase activity in bronchoalveolar lavage fluids of healthy smokers and nonsmokers.

Elastase activity was measured in concentrated, cell-free bronchoalveolar lavage (BAL), using the synthetic substrate butyloxycarbonyl-L-alanyl-L-alanyl-L-prolyl-L-valyl-amino-methylcoumarin. The BAL fluids obtained from young, asymptomatic smokers with normal urine desmosine concentrations 1 h after they had smoked 2 cigarettes showed significant increases in elastase levels compared with those in nonsmoking control subjects [nanomoles substrate hydrolyzed (3 h) per milligram lavage albumin = mean 2.7 +/- 1.9 SD (11 smokers) versus 0.5 +/- 0.4 (11 nonsmokers), p less than 0.01]. Repeated BAL samples were obtained at later times from one smoker with a high initial enzyme value and from one nonsmoking control subject. Elastase activity varied over time, but both subjects consistently remained within their respective group ranges. Inhibition studies on pooled BAL from smokers showed that the elastase activity present had properties of both serine and metalloenzymes, suggesting that neutrophils and/or monocytes (serine enzyme) as well as macrophages (metalloenzyme) contributed to the observed activity. Lung lavage cells obtained from 2 of the smokers and 2 of the nonsmokers were stained with both a chromogenic substrate and by indirect immunofluorescence for the serine enzyme. Positively stained neutrophils were readily found in smokers' lavages, but no, or only rare, positive mononuclear cells could be identified. By contrast, peripheral blood mononuclear cells from all 4 subjects stained positively with either method. These results show that some asymptomatic smokers have significantly more elastase activity in their bronchopulmonary secretions than do nonsmokers (as measured with a low molecular weight synthetic substrate). Furthermore, the enzyme activity recovered in smokers' BAL appears to be derived mainly from neutrophils (serine enzyme) and macrophages (metalloenzyme), rather than from monocytes.

Adult↗
PubMed1981

Pregnancy and chronic obstructive pulmonary disease.

A 40-year-old pregnant patient with severe chronic obstructive pulmonary disease developed respiratory distress and delivered prematurely at 32 weeks' gestation. She required intubation and mechanical ventilation in the postpartum period. Aggressive management of this unusual case resulted in a successful outcome for both the patient and her child.

Adult↗