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Biomedical subjects

S Pillai

Publications and source records attributed to S Pillai.

At least 55 records · Page 3Linked to original sources
PubMed1998

Bacterial profile of sepsis in a neonatal unit in south India.

OBJECTIVE: To study the pattern of sepsis in a neonatal unit in south India and assess the influence of maternal factors on early onset sepsis (EOS). DESIGN: Prospective survey from 1995-1996. SETTING: Medical College Hospital. SUBJECTS: All inborn babies who had clinical signs of sepsis or were born to mothers with potential risk factors for infection were screened for sepsis. Neonatal septicemia was defined as a disease of infants who were younger than 1 month of age, were clinically ill, and had positive blood cultures. RESULTS: Among 13,367 live births in the study period, there were 131 episodes of neonatal septicemia among 125 newborn infants, 18 (14.4%) of whom died. Thirty (24%) had EOS (< or = 48 hours) and 95 (76%) had late onset sepsis (LOS) (> or = 48 hours). Sepsis occurred in 9.8 per 1000 livebirths and 4.4% of all nursery admissions. E. coli and E. fecalis were the predominant organisms causing EOS, while Klebsiella and E. fecalis were the predominant organisms in LOS. The mean gestational age (GA) and birth weight (BW) of babies with EOS was significantly higher than those with LOS. Maternal factors significantly associated with EOS were meconium staining of liquor and multiple vaginal examinations. CONCLUSIONS: The incidence of neonatal bacterial sepsis is 9.8 per 1000 livebirths. E. coli and Klebsiella were the most common organisms causing EOS and LOS, respectively. E. fecalis was also a major pathogen, both in EOS and LOS.

Enterobacteriaceae Infections↗
PubMed1997

Electrophore mass tag dideoxy DNA sequencing.

Toward a goal of dideoxy sequencing DNA utilizing electrophore labels, we prepared four electrophore-labeled DNA oligonucleotide primers. Each primer has a different electrophore and DNA sequence but a common glycol keto (alpha,beta-dihydroxyketo) release group. Cleavage of this latter group by either periodate oxidation or a thermal retroaldol reaction releases the electrophores for detection by mass spectrometry. Successful sequencing data with these primers was obtained by capillary electrophoresis on an ABI Model 310 after fluorescence dideoxy terminator cycle sequencing reactions were conducted. In a separate experiment, it was demonstrated that a cocktail of the four electrophore DNA primers could be detected as a dried sample spot by CO2 laser desorption/capillary collection/gas chromatography electron capture mass spectrometry. These results establish some feasibility for our long-term goal of high-speed multiplex electrophore mass tag dideoxy DNA sequencing. Ultimately we plan to use a higher number of electrophore mass tags and to rely on direct detection of the desorbed electrophores by electron capture time-of-flight mass spectrometry.

Chromatography, High Pressure Liquid↗
PubMed1997

A lymphocyte-specific Ltk tyrosine kinase isoform is retained in the endoplasmic reticulum in association with calnexin.

A lymphocyte-specific murine Ltk tyrosine kinase isoform was previously found to reside in the endoplasmic reticulum and to be potently activated upon treatment of cells with alkylating or thiol-oxidizing agents. Based on these observations, a unique role for Ltk was proposed as an endoplasmic reticulum-resident transmembrane kinase regulated by redox changes (Bauskin, A. R., Alkalay, I., and Ben-Neriah, Y. (1991) Cell 66, 685-696). To analyze why this Ltk isoform is retained in the endoplasmic reticulum, we investigated its behavior in over-expressing cells. Our results indicate that lymphoid Ltk exhibits a dual Nexo/Ccyt and Ncyt/Cexo transmembrane topology in transfected cells. This unusual behavior may be responsible for retention in the endoplasmic reticulum since mutants with an increased number of positive amino acids downstream of the transmembrane segment exhibit a conventional Nexo/Ccyt orientation and proceed to the cell surface. Endoplasmic reticulum-retained Ltk forms a prominent complex with the chaperone calnexin, suggesting that Ltk may be retained by the mechanism that prevents surface expression of inappropriately folded proteins or incompletely assembled protein complexes.

Animals↗
PubMed1997

The presence of a C1-inhibitor-like molecule (C1-INH-L) on human sperm: its involvement in sperm motility.

PROBLEM: An 88-92-kDa C1-inhibitor-like molecule (C1-INH-L) was previously identified to elicit cytotoxic sperm antibody response in infertile men and women. Here, we document that it is present on the human sperm surface and could be detected by an enzyme-labeled immunoglobulin G (IgG) fraction of anti-human C1-INH antibody. METHOD OF STUDY: Western blot analysis, enzyme-lined immunoadsorbent assay (ELISA) and computerized sperm motion analysis. RESULTS: The existence of C1-INH-L on the sperm surface is calcium independent. Phosphatidylinositol-specific phospholipase C (PIPLC), EDTA, and acid (pH 3.0) could not remove the C1-INH-L from sperm, but trypsin did. Activated C1s was able to bind to the sperm surface. Immunofluorescence studies localized the protein to the head and midpiece of the sperm membrane. The C1-INH-L exists on both uncapacitated and capacitated sperm surfaces, which suggests that this protein is a sperm-surface protein. The heat-treated (56 degrees C, 30 min) IgG fraction of anti-C1-INH greatly reduced the percentage of motile spermatozoa and the progressive and path velocities in the absence of complement. CONCLUSION: Our data suggest that C1-INH is a sperm membrane-anchored protein that may have complement and sperm motility regulatory function.

Complement C1 Inactivator Proteins↗
PubMed1997

Utility of a bedside Doppler in tracking left ventricular dysfunction related to hemorrhagic shock.

Treatment of hemorrhagic shock with fluid resuscitation alone results in diastolic dysfunction as measured by peak systolic pressure/end systolic volume ratio (PSP/ESV). The purpose of this study was to test the ability of a simple Doppler device to track diastolic dysfunction in hemorrhagic shock. In this prospective, controlled crossover study, five adult swine were resuscitated from hemorrhagic shock using fluids. Diastolic dysfunction was confirmed using PSP/ESV ratio. The effect of nitroprusside and dobutamine on this diastolic dysfunction was evaluated. Data (PSP/ESV, Doppler-derived acceleration, and oxygen transport parameters) were collected at each stage of the model. Arterial pressure and oxygen transport parameters corrected to baseline values; however, the PSP/ESV and Doppler-derived acceleration failed to correct with fluid resuscitation alone. Treatment with nitroprusside and dobutamine increased oxygen transport parameters, PSP/ESV ratio, and Doppler-derived acceleration significantly. Doppler-derived acceleration tracks left ventricular dysfunction seen in hemorrhagic shock.

Animals↗
PubMed1996

An increased risk of Crohn's disease in individuals who inherit the HLA class II DRB3*0301 allele.

The role of inflammatory T cells in Crohn's disease suggests that inherited variations in major histocompatibility complex (MHC) class II genes may be of pathogenetic importance in inflammatory bowel disease. The absence of consistent and strong associations with MHC class II genes in Caucasian patients with inflammatory bowel disease probably reflects the use of less precise typing approaches and the failure to type certain loci by any means. A PCR-sequence-specific oligonucleotide-based approach was used to type individual alleles of the HLA class II DRB1, DRB3, DRB4, and DRB5 loci in 40 patients with ulcerative colitis, 42 Crohn's disease patients, and 93 ethnically matched healthy controls. Detailed molecular typing of the above alleles has previously not been reported in patients with inflammatory bowel disease. A highly significant positive association with the HLA-DRB3*0301 allele was observed in patients with Crohn's disease (P = 0.0004) but not in patients with ulcerative colitis. The relative risk for this association was 7.04. Other less significant HLA class II associations were also noted in patients with Crohn's disease. One of these associations involved the HLA-DRB1*1302 allele, which is known to be in linkage disequilibrium with HLA-DRB3*0301. These data suggest that a single allele of an infrequently typed HLA class II locus is strongly associated with Crohn's disease and that MHC class II molecules may be important in its pathogenesis.

Alleles↗
PubMed1996

Changes in calcium responsiveness and handling during keratinocyte differentiation. Potential role of the calcium receptor.

Extracellular calcium concentrations (Cao) > 0.1 mM are required for the differentiation of normal human keratinocytes in culture. Increments in Cao result in acute and sustained increases in the intracellular calcium level (Cai), postulated to involve both a release of calcium from intracellular stores and a subsequent increase in calcium influx through nonspecific cation channels. The sustained rise in Cai appears to be necessary for keratinocyte differentiation. To understand the mechanism by which keratinocytes respond to Cao, we measured the acute effects of Cao on Cai and calcium influx in keratinocytes at various stages of differentiation. We then demonstrated the existence of the calcium receptor (CaR) in keratinocytes and determined the effect of calcium-induced differentiation on its mRNA levels. Finally, we examined the role of Cai in regulating both the initial rise in Cai after the switch to higher Cao and the activity of the nonspecific cation channel through which calcium influx occurs. Our data indicate that the acute Cai response to Cao is lost as the cells differentiate and increase their basal Cai. These data correlated with the decrease in CaR mRNA levels in cells grown in low calcium. However, calcium influx as measured by 45Ca uptake increased with differentiation in 1.2mM calcium, consistent with the increase in CaR mRNA in these cells as well as the calcium-induced opening of the nonspecific cation channels. We conclude that the keratinocyte contains a CaR that regulates both the initial release of Cai from intracellular stores and the subsequent increase in calcium flux through nonspecific calcium channels. A rising level of Cai may turn off the release of calcium from intracellular stores while potentiating the influx through the nonspecific cation channels. Differentiation of keratinocytes appears to increase the CaR, which may facilitate the maintenance of the high Cai required for differentiation.

Animals↗
PubMed1996

Load-independent left ventricular function in a hemorrhagic shock model.

Load-independent left ventricular (LV) function has been recently shown to be reversibly depressed in septic shock. The peak systolic pressure to end systolic volume ratio (PSP/ESV) is a load independent measure of LV function. We evaluated PSP/ESV in a porcine model of hemorrhagic shock. Hemorrhagic shock was induced in five adult swine by arterial bleeding to a mean arterial pressure of 45-65 mmHg. This hypotension was maintained for 30 min, and then each animal was resuscitated to baseline mean arterial pressure using shed blood and crystalloid solution. Data (echocardiographically derived ejection fraction and oxygen transport parameters) were collected at baseline, after 30 min of hypotension and postresuscitation. Although the cardiac index, a marker for systolic function, and the mean arterial pressure, as well as oxygen delivery and consumption returned to baseline levels, the PSP/ESV ratio remained low despite adequate fluid resuscitation. This model provides a reproducible hemodynamically stable cardiac dysfunction associated with hemorrhagic shock.

Animals↗
PubMed1996

Effect of lactic acid isomers on keratinocyte ceramide synthesis, stratum corneum lipid levels and stratum corneum barrier function.

Alpha-hydroxy acids are effective agents for the treatment of skin xerosis and it is known that, following treatment with lotions containing D,L-lactic acid, the stratum corneum prevents xerosis more effectively. To date, the relative efficacy of the different isomers of lactic acid has not been evaluated and the mode of action of lactic acid in improving stratum corneum resilience is not known. The objective of the present studies was to determine the effects of lactic acid isomers on keratinocyte ceramide biosynthesis, stratum corneum barrier function and the resistance of the stratum corneum to the appearance of skin xerosis. In vitro, lactic acid enhanced the production of ceramides by keratinocytes. L-Lactic acid was more effective than the D isomer (300% increase vs 100% increase). Carbon label from lactic acid was incorporated into all keratinocyte lipid species and a greater incorporation of label into ceramides was achieved with L-lactate than with D-lactate. In vivo, lactic acid increased the levels of stratum corneum ceramides. Whereas, lotions containing L-lactic acid resulted in the greatest increase (48% increase) followed by D,L-lactic acid (25% increase), D-lactic acid had no effect on stratum corneum ceramide levels. The increases in stratum corneum ceramide levels following lactic acid treatment also led to improvements in stratum corneum barrier function, measured by transepidermal water loss following a challenge to the skin with SLS and in the regression phase of a moisturization efficacy study. Significant improvements in barrier function and resistance to the appearance of skin xerosis were observed following L-lactic acid and D,L-lactic acid, but not following D-lactic acid treatment. From these results we believe that lactic acid, particularly the L isomer, stimulates ceramide biosynthesis leading to increased stratum corneum ceramide levels which results in superior lipid barrier and a more effective resistance against xerosis.

Adult↗
PubMed1996

Induction of pneumococcal polysaccharide-specific mucosal immune responses by oral immunization.

Liposome and cholera toxin (CT) are considered to be effective antigen delivery vehicles and adjuvants for mucosal vaccines. The effect of these antigen delivery systems on adjuvant responses to mucosally administered pneumococcal polysaccharide (Pnup) was investigated in this study. Both mucosal (e.g. oral) and systemic (i.p.) immunization of mice with purified preparations of Pnup type 23F induced antigen-specific IgM responses in sera. Interestingly, oral immunization of as little as 10 micrograms of Pnup type 23F was sufficient to induce systemic IgM responses. Pnup-specific IgM antibodies peaked by day 7 and no booster responses were evident after a second dose on day 14. In order to examine whether IgG and IgA Pnup-specific immune responses are induced by mucosal immunization, the mucosal adjuvant CT was mixed with Pnup type 23 as an oral vaccine. Co-oral administration of CT and Pnup type 23F resulted in the induction of Pnup-specific faecal IgA antibodies. These results were confirmed by detecting antigen-specific IgA-spot-forming cells in mononuclear cell suspensions prepared from the intestine of immunized mice. These findings suggest that oral immunization with Pnup in the presence of mucosal adjuvants, such as CT, could induce Pnup-specific IgA responses whereas Pnup alone did not. In an attempt to further enhance antigen-specific antibody responses, Pnup type 23F was encapsulated in liposomes and used as mucosal vaccine. However, immunogenicity of Pnup was not improved.

Administration, Oral↗
PubMed1996

Rectal pH measurement in tracking cardiac performance in a hemorrhagic shock model.

OBJECTIVE AND DESIGN: We evaluated the utility of rectal mucosal pH measurement for tracking cardiac performance in hemorrhagic shock as compared with gastric tonometry. MATERIALS AND METHODS: Hemorrhagic shock was induced in five adult swine to a mean arterial pressure of 45-65 mm Hg. Hypotension was maintained for 30 minutes, resuscitation was accomplished with the shed blood and lactated Ringer's solution (3x blood volume). Gastric tonometry, rectal pH, and oxygen transport data were obtained at baseline, 0, and 30 minutes after onset of hypotension and after resuscitation. RESULTS: Intramucosal pH readings from gastric tonometry and rectal mucosal pH both showed a significant change from baseline to 0 and 30 minutes after onset of hypotension. Data after resuscitation were found to be statistically the same as baseline values. CONCLUSIONS: Rectal mucosal pH tracks cardiac performance as well as does gastric tonometry in hemorrhagic shock without as many limitations.

Animals↗
PubMed1996

Squamous carcinoma cell lines fail to respond to 1,25-Dihydroxyvitamin D despite normal levels of the vitamin D receptor.

Squamous carcinoma cells (SCC) fail to differentiate under conditions that are favorable for the growth and differentiation of normal human keratinocytes. Human keratinocytes differentiate from a highly proliferative basal cell to a terminally differentiated cornified cell in culture in the presence of physiological levels of extracellular calcium. 1,25-Dihydroxyvitamin D (1,25[OH]2D3) potentiates this process. Previous studies have shown that the differentiation process in keratinocytes is associated with increased expression of the genes for involucrin and transglutaminase, the products of which participate in cornified envelope formation. The mRNA for involucrin and transglutaminase was not detected in the SCC lines studied (viz. SCC4, 12B2, 12F2, A431, and HACAT) when they were grown in serum free medium. Addition of at least 2% fetal bovine serum for 48 h triggered the expression of these genes, which could then be maintained in the absence of serum. Serum was not required for induction of these genes in keratinocytes. In these cells, 1,25(OH)2D3 stimulated the expression of involucrin and transglutaminase in a concentration-dependent manner, while the SCC lines failed to respond to 1,25(OH)2D3 regardless of whether these cells had been pre-exposed to serum. An important factor that mediates 1,25(OH)2D3-stimulated gene expression is the vitamin D receptor, but vitamin D receptor mRNA levels in all the SCC lines examined were comparable to those in keratinocytes. Furthermore, the vitamin D receptor protein levels in SCC lines as assessed by ligand-binding analysis were comparable to those of keratinocytes. Thus, the mediators of 1,25(OH)2D3 action on gene expression other than the vitamin D receptor may be missing or defective in SCC lines, whereas the mediators of as yet undefined agents in serum may be better expressed in SCC lines than in keratinocytes. Our results indicate that, although SCC lines are capable of expressing the genes for the proteins involved in differentiation, the control of the expression of these genes by 1,25(OH)2D3 is abnormal in SCC despite the presence of a functional vitamin D receptor in concentrations equivalent to those in keratinocytes.

Animals↗
PubMed1996

Antibodies to endometrial transferrin and alpha 2-Heremans Schmidt (HS) glycoprotein in patients with endometriosis.

PROBLEM: Identifying the endometrial antigens inciting autoimmunity is important in setting up an antibody assay for a non-invasive diagnosis and clinical monitoring of endometriosis. METHODS: Two-dimensional gel electrophoresis of endometrial extracts, Western blot analysis, passive hemagglutination and enzyme-linked immunosorbent assay (ELISA), amino acid sequencing and molecular studies were done on chosen antigens. Forty-six women with endometriosis, 4 women with uterine leiomyomata, 4 with pelvic adhesions, 3 with repeat Cesarean sections (conditions that coexist with or predispose to endometriosis) and 46 controls participated. RESULTS: Antigens with molecular weights (MW) of 64 kDa [isoelectric point (pI) of 3.5-4.0] and 72 kDa (pI of 4.5) bound to IgG in all patients with endometriosis, but not the controls. Amino acid sequencing of the proteins revealed that they had homology to alpha 2-Heremans Schmidt (HS) glycoprotein (MW: 64 kDa) and transferrin (MW: 72 kDa). Endometriosis patients had significant antibody levels to these two proteins (predictive value of 80-90%). The analysis of patients' endometrial RNA detected the message for alpha 2-HS glycoprotein and transferrin. Albumin (pI 5.5) and collagen (pI 3.5) failed to elicit antibody responses. CONCLUSIONS: Patients with endometriosis have significant antibodies to endometrial transferrin and alpha 2-HS-glycoprotein. We can effectively use an antibody assay using these antigens for diagnosing endometriosis.

Adult↗
PubMed1996

Molecular weights and isoelectric points of sperm antigens relevant to autoimmune infertility in men.

PURPOSE: We determined the molecular weights and isoelectric points of antigens in the uncapacitated and capacitated spermatozoa of fertile men binding to the serum immunoglobulin G (IgG) from 8 autoimmune infertile men and 8 fertile nonautoimmune men. MATERIALS AND METHODS: We used double fluorochrome cytotoxicity and immunobead binding assays to determine the sperm antibody status of the study subjects. 2-Dimensional gel electrophoresis and Western blot analysis were used to determine the molecular weights and isoelectric points of sperm antigens binding to serum IgG from these men. Amino acid sequencing of the digested peptides of chosen proteins was accomplished. Immune reactivity to the proteins in autoimmune infertile men was further verified. RESULTS: Serum IgG from fertile men failed to react significantly. Serum IgG from all autoimmune men (100%) showed significant binding to proteins with a molecular weight of 92 kDa. and isoelectric points of 3.5 to 4.0 in the capacitated spermatozoa. Six of 8 infertile men (75%) had serum IgG binding to capacitated sperm antigens with a molecular weight of 18 kDa. and isoelectric points of 4.5 to 5.2. Amino acid sequencing of peptides of the 92 kDa. protein matched complement component 1 (C1) inhibitor, with noted differences in the amino acid sequencing from the latter. The 18 kDa. protein matched calmodulin. We verified that serum IgG from autoimmune infertile men bound with C1 inhibitor and ascertained that the 92 kDa. protein in the spermatozoa was C1 inhibitor-like protein. CONCLUSIONS: Significant antibody responses to C1 inhibitor-like protein and calmodulin were noted in autoimmune men. Both of these proteins may be of testicular origin and these autoimmune responses may be highly relevant to infertility.

Amino Acid Sequence↗
PubMed1996

Changes in oxygenation and compliance as related to body position in acute lung injury.

Body positioning during mechanical ventilation for acute lung injury has not been studied in a detailed manner. We evaluated the relationship between oxygenation, compliance, and body position during mechanical ventilation of patients with acute lung injury (ALI). Sixteen patients on mechanical ventilation with a diagnosis of ALI (partial pressure of oxygen/fraction of inspired oxygen <300 and no clinical evidence of congestive heart failure) were prospectively studied. Each patient was placed in a supine position followed by a 30 degrees head elevation and a 45 degrees head elevation. Data obtained in each position (after a 45-60 minute equilibration time) included static pulmonary compliance and partial pressure of oxygen from arterial blood gas sampling. Oxygenation is not improved and compliance is adversely affected by upright body positioning as compared to the supine position in patients receiving mechanical ventilation for ALI.

Adult↗
PubMed1996

Synergy between vitamin D precursor 25-hydroxyvitamin D and short chain ceramides on keratinocyte proliferation and differentiation.

The active vitamin D metabolite, 1,25-dihydroxyvitamin D3 (1,25D), and its analogs induce normal human keratinocyte differentiation and are used for the treatment of psoriasis. Long-term topical use of 1,25D, however, causes hypercalcemia. The precursor of 1,25D, 25-hydroxyvitamin D3 (25D) is converted to 1,25D in the keratinocyte in a regulated manner. The action of 1,25D is reported to be mediated, at least in part, by cellular ceramides in the leukemia cell line, HL-60 cells. Therefore, in this study we evaluated the synergy between 25D and short chain cell permeable ceramides (SCC) or synthetic analogs of ceramides on keratinocyte growth and differentiation in vitro. C2 ceramide (acetyl sphingosine) synergistically enhanced the growth inhibitory effect of 25D and 1,25D in a concentration-dependent manner. Short chain analogs of ceramide-like compounds, neoceramides and pseudoceramides, also inhibited keratinocyte proliferation and acted in synergy with 25D and 1,25D. SCC alone increased transglutaminase and cornified envelope levels. 25D potentiated this prodifferentiating effect of SCC. Twenty-four-hour preincubation with SCC did not alter 25D or 1,25D uptake into keratinocytes. These studies demonstrate a synergy between vitamin D metabolites and ceramides in human keratinocytes and indicate the potential of using 25D as an effective and safer alternative to deliver 1,25D benefits to the epidermis.

Calcifediol↗
PubMed1995

Association of activated phosphatidylinositol 3-kinase with p120cbl in antigen receptor-ligated B cells.

A 120-kDa protein that is tyrosine-phosphorylated upon antigen receptor ligation in B lymphocytes has been identified as the product of the c-cbl protooncogene. Tyrosine phosphorylation of Cbl depends on the efficient association of membrane immunoglobulin heavy chains with the Ig alpha/beta heterodimer but is unimpaired in splenic B cells from the Xid mouse. Cross-linking of membrane IgM and membrane IgG, but not of CD40, leads to the tyrosine phosphorylation of Cbl. In receptor-ligated B lymphocytes, p120cbl associates with an 85-kDa protein that has been identified as the 85-kDa subunit of phosphatidylinositol 3-kinase.

Animals↗