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J Varghese

Publications and source records attributed to J Varghese.

26 records · Page 2Linked to original sources
PubMed1993

Cetyltrimethylammonium chloride as a surfactant buffer additive for reversed-polarity capillary electrophoresis-electrospray mass spectrometry.

The rapid analysis of picomole quantities of various cationic molecules (laser dyes, tripeptides and larger bioactive peptides) has been achieved by on-line capillary electrophoresis-electrospray mass spectrometry (CE-ES-MS). Use of the cationic surfactant, cetyltrimethylammonium chloride (CTAC) in the CE buffer greatly facilitated the analyses. Under reversed-polarity conditions (negative potential at the source vial), CTAC induces electroosmotic flow towards the mass spectrometer, presumably due to the creation of a cationic layer on the inner surface of the fused-silica capillaries. CTAC diminishes analyte-capillary wall interactions, allowing efficient separations and symmetrical peak shapes. It may be used over a wide range of pH values without loss of electroosmotic flow. Added selectivity, provided by the surfactant properties of CTAC, played a critical role in resolving closely related tripeptides as well as larger (five to thirteen amino acid units) peptides. Above the critical micelle concentration of CTAC, interactions with the pseudostationary micellar phase increased selectivity even for ionic analytes.

Amino Acid Sequence↗
PubMed1993

Severe acute metabolic alkalosis.

We have presented the case of a 34 year old male patient who was admitted with severe metabolic alkalosis (MA). Peak serum HCO3 was 96 mg/dl and compensatory PCO2 was 95 which, to our knowledge, has never been reported before in a patient with MA. MA was probably generated by consumption of high amount of NaHCO3 and renal impairment and maintained by impaired renal function due to volume depletion hypokalemia and hyochloremia. The patient was successfully treated with IV administration of saline and KCL.

Adult↗
PubMed1990

Antigen-induced T-cell changes: modulation by pharmacologic agents.

To determine the effect of pharmacologic modulation of alterations of peripheral blood T-cell subsets caused by antigen-induced bronchoconstriction, we administered albuterol immediately after antigen-induced bronchoconstriction in a double-blind to protocol to 12 atopic asthmatic subjects. We also administered cromolyn sodium before antigen to 7 of the same subjects. Peripheral blood T-cell subset composition (CD4, CD8, Ia) of a highly purified T-cell preparation was determined before, 24, 48, 72, and 168 h after bronchoconstriction. We found that placebo inhalation immediately after antigen-induced bronchoconstriction did not affect subsequent peripheral blood T-cell subset changes (decrease in CD4+ and increase in Ia+ T lymphocytes). In contrast, inhaled albuterol abolished these T-cell subset changes. Although cromolyn sodium significantly decreased the severity of antigen-induced bronchoconstriction, it did not affect T-cell subset composition changes at the dosage used. We conclude that albuterol can ablate T-cell subset changes associated with antigen-induced bronchoconstriction. Cromolyn sodium ameliorates bronchoconstriction, but has no affect on T-cell subset composition changes. This implies that T-cell changes and bronchoconstriction caused by antigen inhalation are mediated through different pathways.

Administration, Inhalation↗
PubMed1990

Biochemical features of major organ of Corti proteins (OCP-I and OCP-II) including partial amino acid sequence.

Further biochemical and biophysical characterization of two low-molecular-weight, strongly acidic proteins that are present at extremely high levels in the organ of Corti, tentatively named OCP-I and OCP-II, is presented. The two proteins are also present, although at much lower levels, in the vestibular end-organs and a variety of other inner ear tissues; they have not been observed in other systems. OCP-I and II are highly soluble and do not contain appreciable amounts of carbohydrate. The two proteins, originally described in the guinea pig, are compared electrophoretically with the corresponding proteins in several other mammalian species. Preliminary data on the amino acid composition of the two proteins are presented. Moreover, the amino-terminal sequence of a 22-residue segment of OCP-II is shown and compared to the sequences of known proteins.

Amino Acid Sequence↗
PubMed1988

Immunohistochemical assessment of the effect of chemical and mechanical stimuli on cAMP and prostaglandin E levels in human gingival fibroblasts in vitro.

These were evaluated by: (1) a combined immunohistochemical-microphotometric procedure (IH) and (2) conventional radiometric assays. Human gingival fibroblasts were in the sixth passage, grown and maintained in Dulbecco minimal essential medium (DMEM) supplemented with 10 per cent horse serum. For chemical and hormonal stimuli, cells (2 x 10(4] were seeded on tissue-culture chamber/slides, and incubated with graded doses of either parathyroid hormone (PTH) or prostaglandin E2 (PGE2) for assessment of their adenosine-3',5'-monophosphate (cAMP) levels, and with indomethacin or colchicine for their effect on PGE levels. For mechanical stimuli, cells (1 x 10(6] were seeded on culture dishes with a flexible plastic membrane and stretched for 5, 30, 60 or 120 min by placing the membrane over a convex surface and weighting the dish cover. After freeze drying, cells were stained by an immunoperoxidase technique for either cAMP or PGE, using monoclonal antibodies. The staining intensity of fibroblasts was determined at 600 nm wavelength. Per cent light absorbance of 15 cells in each slide was measured and the results tested by analysis of variance. The gingival fibroblasts responded to the drugs and hormones in a dose- and time-related fashion. Stretching significantly increased their synthesis of PGE with concomitant increase in cAMP. The IH results were compared with the radiometric assays to confirm the validity of this technique; both assays were valid for describing the quantitative responses of these cells to the stimuli. In particular, the IH method could localize those intracellular sites which demonstrated chances in relative cAMP and PGE concentrations in response to hormonal stimuli.

Colchicine↗
PubMed1976

Sudden death among postoperative patients with tetralogy of Fallot: a follow-up study of 243 patients for an average of twelve years.

Two hundred and forty-three patients were evaluated following total correction of tetralogy of Fallot with special emphasis on postoperative conduction disturbances and on the occurrence of sudden death. The average follow-up period was 12 years with a range of 6 1/2 to 16 1/2 years. Sudden death occurred in seven patients. Four deaths were among those with right bundle branch block pattern (RBBB) and three of the four had premature ventricular contractions (PVC) for more than one month postoperatively. PVCs were documented in ten of the 158 patients with RBBB; sudden death occurred in three (30%). Three of the ten (30%) patients with trifascicular block pattern (TB) died suddenly, while no deaths occurred in 24 patients with bifascicular block pattern (BB). Progression of RBBB to BB and TB occurred in 18 patients from one month to seven years postoperatively (58% of BB and 40% of TB). The risk of sudden death in patients with RBBB and PVCs following tetralogy repair is high and warrants consideration of suppressive therapy. TB also carries a high risk. The finding that RBBB may progress to BB or TB mandates long-term careful follow-up of all tetralogy patients with postoperative conduction disturbances.

Adolescent↗
PubMedDate not supplied

The role of maternal affect mirroring on social expectancies in three-month-old infants.

The role of maternal affect mirroring on the development of prosocial behaviors and social expectancies was assessed in forty-one 2- to 3-month-old infants. Prosocial behavior was characterized as infants' positive behavior and increased attention toward their mothers. Social expectancies were defined as infants' expectancy for affective sharing. Mothers and infants were observed twice, approximately 1 week apart. During Visit 1, mothers and infants were videotaped while interacting over television monitors for 3 min. During Visit 2, infants engaged in a live, 3-min interaction with their mothers over television monitors (live condition) and they also viewed a replay of their mothers' interaction from the preceding week (replay condition). The order of conditions was counterbalanced. Maternal affect mirroring was measured according to the level of attention maintenance, warm sensitivity, and social responsiveness displayed. A natural split was observed with 58% of the mothers ranking high and 42% ranking low on these affect mirroring measures (HAM and LAM, respectively). Infants in the HAM group ranked high on prosocial behaviors and social expectancy--they discriminated between live and replay, conditions with smiles, vocalizations, and gazes. Infants in the LAM group ranked low on these variables--they gazed longer during the live condition than during the replay condition, but only when the live condition was presented first; however, they did not smile or vocalize more. These findings indicate that there is a relation between affect mirroring and social expectancies in infants.

Adult↗