Search PubMed⌕ Search

Biomedical subjects

S Kannan

Publications and source records attributed to S Kannan.

At least 73 records · Page 4Linked to original sources
PubMed1999

Cripto-1 indirectly stimulates the tyrosine phosphorylation of erb B-4 through a novel receptor.

Cripto-1 (CR-1) is a recently discovered protein of the epidermal growth factor family that fails to directly bind to any of the four known erb B type 1 receptor tyrosine kinases. The present study demonstrates that CR-1 indirectly induces tyrosine phosphorylation of erb B-4 but not of the epidermal growth factor-related receptors erb B-2 and erb B-3 in different mouse and human mammary epithelial cell lines. In addition, down-regulation of erb B-4 in NMuMG mouse mammary epithelial cells and in T47D human breast cancer cells, using an anti-erb B-4 blocking antibody or a hammerhead ribozyme vector targeted to erb B-4 mRNA, impairs the ability of CR-1 to fully activate mitogen-activated protein kinase. Finally, chemical cross-linking of 125I-CR-1 to mouse and human mammary epithelial cell membranes results in the labeling of two specific bands with a molecular weight of 130 and 60 kDa, suggesting that the CR-1 receptor represents a novel receptor structurally unrelated to any of the known type I receptor tyrosine kinases. In conclusion, these data demonstrate that CR-1, upon binding to an unknown receptor, can enhance the tyrosine kinase activity of erb B-4 and that a functional erb B-4 receptor is required for CR-1-induced MAPK activation.

Animals↗
PubMed1999

Moderately severe anaphylactoid reaction to pentastarch (200/0.5) in a patient with acute severe asthma.

The use of synthetic colloids for resuscitation and volume replacement is common in the intensive care unit. Although adverse reactions have been reported to colloid solutions, the incidence of severe reactions to the starch derivatives is low. We report a case of an anaphylactoid reaction to pentastarch (200/0.5) in a young asthmatic who received it as a fluid challenge in the intensive care unit. The pathogenesis and implications of such a reaction in an asthmatic are discussed.

Adult↗
PubMed1999

Differential lung physiotherapy using a double lumen tube in flail chest and refractory lung atelectasis.

The management of refractory lung atelectasis in a patient with flail chest can be difficult. Treatment of lung atelectasis is complicated by practical problems with the application of chest physiotherapy, postural drainage and incentive spirometry. Although double lumen endotracheal tubes have been used in such cases for the purpose of differential lung ventilation, the use of differential lung physiotherapy has not been reported before. This report describes the successful application of this technique in a patient with flail chest and refractory lung atelectasis.

Adult↗
PubMed1999

Severe head injury patients in a multidisciplinary ICU: are they a burden?

OBJECTIVE: Patients with severe head injury (HI) are often considered to be a burden in a multidisciplinary intensive care unit (ICU). This study was undertaken to compare the severe closed HI patients with all other patients in the ICU in terms of age group involved, stay in the unit, complications and outcome. DESIGN: Retrospective analysis. SETTING: Multidisciplinary ICU of a tertiary care hospital in Northern India. PATIENTS AND PARTICIPANTS: All the patients admitted to the ICU between January 1995 and December 1997. The patients were classified into two groups: group A comprising patients with severe closed HI and group B consisting of all other patients. RESULTS: The mean age of the patients was around 30 years in both the groups. The average stay of the patients in the unit was 12.71 +/- 11.9 days in group A, compared to 9.9 +/- 14.4 days for group B (p < 0.05). The duration on the ventilator or on an endotracheal airway was not different between the groups (p > 0.05). The mortality in group A was 46.8 % and that in group B was 38.5 % (p > 0.05). The mortality was directly proportional to the age in group A. Hypotension, renal failure and septicaemia were the commonest complications in both the groups but the difference was not statistically significant. CONCLUSIONS: This study demonstrates that patients with severe HI do not pose an extra burden in a multidisciplinary ICU.

Adolescent↗
PubMed1999

Immunolocalization of the sarcolemmal Ca2+/Mg2+ ecto-ATPase (myoglein) in rat myocardium.

Cardiac plasma membrane Ca2+/Mg2+ ecto-ATPase (myoglein) requires millimolar concentrations of either Ca2+ or Mg2+ for maximal activity. In this paper, we report its localization by employing an antiserum raised against the purified rat cardiac Ca2+/Mg2+ ATPase. As assessed by Western blot analysis, the antiserum and the purified immunoglobulin were specific for Ca2+/Mg2+ ecto-ATPase; no cross reaction was observed towards other membrane bound enzymes such as cardiac sarcoplasmic reticulum Ca(2+)-pump ATPase or sarcolemmal Ca(2+)-pump ATPase. On the other hand, the cardiac Ca2+/Mg2+ ecto-ATPase was not recognized by antibodies specific for either cardiac sarcoplasmic reticulum Ca(2+)-pump ATPase or plasma membrane Ca(2+)-pump ATPase. Furthermore, the immune serum inhibited the Ca2+/Mg2+ ecto-ATPase activity of the purified enzyme preparation. Immunofluorescence of cardiac tissue sections and neonatal cultured cardiomyocytes with the Ca2+/Mg2+ ecto-ATPase antibodies indicated the localization of Ca2+/Mg2+ ecto-ATPase in association with the plasma membrane of myocytes, in areas of cell-matrix or cell-cell contact. Staining for the Ca2+/Mg2+ ecto-ATPase was not cardiac specific since the antibodies detected the presence of membrane proteins in sections from skeletal muscle, brain, liver and kidney. The results indicate that Ca2+/Mg2+ ecto-ATPase is localized to the plasma membranes of cardiomyocytes as well as other tissues such as brain, liver, kidney and skeletal muscle.

Adenosine Triphosphatases↗
PubMed1999

Infant feeding practices of Anglo American and Asian Indian American mothers.

OBJECTIVE: To compare infant feeding practices of Anglo-American (AA) (n = 25) and Asian-Indian American (AIA) mothers (n = 25) residing in the southeastern United States. METHODS: Feeding practices (breast-feeding, formula-feeding, introduction of solid foods) were assessed at infant ages one, three, six, nine and twelve months for a total of 250 interviews conducted in the home. Mothers' sources of information about infant feeding practices and dietary intakes of their infants were collected (24-hour recalls). RESULTS: Compared to their AIA counterparts, AA mothers breast-fed for significantly longer durations and introduced formula and solid foods into the infants' diet at a later age (p<0.05). Throughout the first year, AA mothers relied primarily upon health professionals for infant feeding information compared to AIA mothers, who sought information primarily from the family network during the first six months and relied more on health professionals during the second six months of the infant's life. Throughout the first twelve months, infants of both groups exceeded 100% of the RDA for energy, protein, calcium, iron, vitamin A, and vitamin C. CONCLUSION: Health professionals, including nutrition educators, should educate AIA mothers about and encourage AA mothers to follow current feeding recommendations and guidelines about breast-feeding, formula-feeding and introducing solid foods.

Adult↗
PubMed1999

Identification of volatile compounds from cheek glands of lesser bandicoot rats and assessment of behavioural response for identified compounds.

Check gland secretions were collected from sexually mature male and female rats to identify the volatile compounds using gas chromatography linked mass spectroscopy with a modified head space technique. Twenty one volatile fractions including alkanes, aliphatic acids, esters and alcohols were found. Three compounds viz. 3-octen-1-ol (E) (I), cyclopentane undecanoic acid (II) and 2,4,6,8 tetramethyl-l-undecane (III) were present in very high concentrations in both male and female rats. In addition, the estrus female contained another compound, L-alanine, 1,1-dimethyl ethyl ester. On the basis of odour preference tests the compounds I, II and III were found to attract both male and female of the homotypic species. In contrast, the fourth compound present in the female attracts the opposite sex. The results suggest that the volatile fractions have unique function and the level of attraction varies from compound to compound.

Animals↗
PubMed1998

Molecular cloning of rat cardiac sarcolemmal Ca2+/Mg2+ ectoATPase (Myoglein).

Rat cardiac sarcolemmal Ca2+/Mg2+ ectoATPase (Myoglein), a membrane-bound enzyme requiring millimolar concentrations of Ca2+ or Mg2+ for maximal hydrolysis of ATP, has been purified to apparent homogeneity. Tryptic digestion and amino acid sequencing was used to design an oligonucleotide probe for screening a rat heart cDNA library; this produced a partial cDNA clone (pND2.1), and sequencing of a 400 base pair portion revealed a 100% homology to human platelet CD36. Northern blotting with pND2.1 detected a 3.1 kb transcript in rat heart but not in other tissues. Interspecies expression analysis (cardiac tissue total RNA blot probed with pND2.1) detected a approximately 2.0 kb transcript in canine, rabbit and porcine heart, whereas transcripts of a 4.1 kb, approximately 3.0 kb and 2.1 kb were observed in human cardiac tissue. A rat genomic DNA Southern blot, probed with pND2.1, indicated that there was a single copy of the gene in the rat genome. Expression of the pND2.1 cDNA in E. coli produced an 89 kDa polypeptide recognized by anti-human CD36 antibody but not by anti-rat Ca2+/Mg2+ ectoATPase antibody. It is concluded that rat cardiac Ca2+/Mg2+ ectoATPase is tightly associated with a protein highly homologous to the adhesion molecule CD36.

Adenosine Triphosphatases↗
PubMed1998

Anaesthesia in Poland syndrome.

PURPOSE: To describe the anaesthetic management of a child with Poland syndrome for CT scan. CLINICAL FEATURES: An eight-month-old child presented with left upper limb hypoplasia and chest wall deformity with absence of ribs on the left side for CT scan of thorax. Pulsations of the heart could be seen along with paradoxical respiration over the defect. The trachea was intubated and the lungs ventilated manually to avoid inadequate ventilation and hypoxia. CONCLUSIONS: The unilateral absence of ribs leads to poor development of subatmospheric pressure in the thorax and paradoxical respiration, and may cause inadequate pulmonary ventilation and hypoxia. In the present case, positive pressure ventilation was chosen to maintain ventilation during the procedure.

Anesthesia, Inhalation↗
PubMed1998

Biophysical characterization of rat cardiac Ca2+/Mg2+ ecto-ATPase (myoglein).

Sarcolemmal Ca2+/Mg2+ ecto-ATPase (Myoglein; MW 180 kD) is a membrane bound enzyme which requires a millimolar concentration of either Ca2+ or Mg2+ for maximal hydrolysis of ATP. The isoelectric point (pI) of the cardiac ecto-ATPase was 5.7. The purified Ca2+/Mg2+ ecto-ATPase from the rat heart sarcolemmal appeared as a single band with MW approximately 90 kD in the SDS-PAGE. In order to understand the nature of this enzyme, the 90 kD band in the SDS-PAGE was electroeluted; the analysis of the eluate showed 2 prominent bands with MW approximately 90 and 85 kD. The presence of 2 bands was further confirmed by gradient gel (10-20%) electrophoresis in 0.375 M Tris-HCl buffer, pH 8.8. Analysis of the purified Ca2+/Mg2+ ecto-ATPase as well as the electroeluted protein in a non-equilibrium linear two dimensional electrophoresis (Ampholyte pI 3.0-10.0) also showed two distinct bands. Mass spectroscopic analysis of the enzyme using different matrix combinations revealed the presence of multi-components indicating microheterogeneity in the protein structure. Treatment of the ecto-ATPase with DL-dithiothreitol did not alter the pattern of mass spectroscopic analysis and this indicated that the microheterogeneity may be due to some posttranslational modifications. It is concluded that rat cardiac Ca2+/Mg2+ ecto-ATPase is an acidic protein having two subunits. Furthermore, the enzyme shows microheterogeneity in its molecular structure.

Adenosine Triphosphatases↗