Search PubMed⌕ Search

Biomedical subjects

P Sinha

Publications and source records attributed to P Sinha.

At least 91 records · Page 5Linked to original sources
PubMed1999

Protein A of Staphylococcus aureus evokes Th1 type response in mice.

Protein A (PA) of Staphylococcus aureus is known to elicit several cytokines such as IFN gamma, TNF alpha and IL1. However, it has not been delineated yet as to which differentiation pathway lymphocytes follow after stimulation by PA. In this report, we attempted to collect such evidences. Cytokines, such as IFN gamma, IL2, IL4, IL6, IL10, TNF alpha, IL1alpha and IL1beta were measured in serum by ELISA. Our results show that 1 microg dose of PA stimulates the production of IFN gamma (115 +/- 5 pg/ml), TNF alpha (250 +/- 8 pg/ml) and IL1alpha (100 +/- 5 pg/ml) as compared to control levels of, 22 +/- 2, 20 +/- 2 and 35 +/- 3 pg/ml respectively whereas IL2 and IL1beta secretion were less (beyond the lower detection limit of the kit and 25 +/- 1 pg/ml, respectively) as compared to control (28 +/- 2 and 52 +/- 4 pg/ml, respectively). Larger dose of PA (10 microg) increases the expression of IL2 (75 +/- 3 pg/ml), TNF alpha (1380 +/- 120 pg/ml), IL1alpha (495 +/- 10 pg/ml) and IL1beta (110 +/- 7 pg/ml) as compared to controls described above. We also observed that 1 microg dose of PA decreases IL4, IL6 and IL10 secretion to 9 +/- 1, 10 +/- 1 and 10 +/- 2 pg/ml, respectively, whereas 10 microg dose also decreased them to 11 +/- 1, 12 +/- 2 and 30 +/- 4 pg/ml, respectively as compared to the background controls, i.e. 50 +/- 5, 50 +/- 2 and 215 +/- 9 pg/ml respectively. The ratio of IFN gamma to IL4 increased and the peak value at 4 h, came to 13 +/- 1 and 9.6 +/- 0.5 with 1 microg and 10 microg PA, respectively, which is an established parameter indicating a Th1 type response. Flow cytometry analysis of CD4+/CD8+ cells, and c-myc protein expression by splenocytes indicate that 1 microg dose of PA causes 2-fold increase of CD4+ cells with no change in CD8+ cells, and 10-fold increase in c-myc protein, whereas 10 microg dose increases CD4+ cells 4-fold, CD8+ cells 3-fold and c-myc protein 100-fold. The cell cycle data shows an induction of apoptosis in thymocytes and splenocytes with the large dose (10 microg), whereas the 1 microg dose does not show any apoptosis. This report indicates that a Th1 response is induced in mice, after PA inoculation at a dose of 1 microg animal. Thus, cytokine mediated therapeutic strategies should consider the fact that an induction of large concentration of some cytokines might become detrimental to the host.

Animals↗
PubMed1999

S. aureus superantigen protein A expands CD4(+)/CD8(+)/CD19(+)/CD34(+) cells in mice: a potential immunorestorer.

Protein A (PA) of Staphylococcus aureus is known for its immunostimulatory, anti-cancer, and anti-toxic properties. The present study revealed that PA stimulates specific immunocytes to act as a potential immunorestorer. It has also been shown that the percentage of various cell types bearing different clusters of differentiation markers, e.g., CD4(+), CD8(+), CD19(+), increases considerably after inoculation with PA. It has also been observed that CD34(+) progenitor cells of bone marrow also increased significantly (P < 0.05) upon PA treatment. PA significantly elevated Th-1 cytokines, e.g., IFN-gamma, TNF-alpha, and IL-1alpha. The increased percentages of CD4(+), CD8(+), CD19(+), CD34(+) cells and elevated cytokine levels in PA treated animals may contribute to the reported anti-tumor, anti-fungal, anti-parasitic, and anti-toxic properties of PA. Since in various diseased conditions and during toxic drug therapy lymphocytes bearing such differentiation markers get suppressed, this type of approach could help in immunorestoration of the host. These findings might help in designing therapeutic approaches toward various diseases which cause immunosuppression.

Animals↗
PubMed1999

Molecular modeling and experimental approaches toward designing a minimalist protein having Fc-binding activity of Staphylococcal protein A.

Protein A (PA), a cell wall constituent of Staphylococcus aureus, has got the unique property of binding with the Fc fragment of IgG from various species. The sequence data indicate five highly homologous Fc-binding regions in protein A. Computer sequence analysis provided the tryptic and chymotryptic fragments of IgG-binding domains of protein A. Molecular modeling in conjunction with molecular mechanical calculation has been used to search for the smallest possible proteolytic fragments of PA, still retaining Fc-binding activity. A 20-residue peptide (typtic fragment) and a 16-residue peptide (chymotryptic fragment) have been indicated, by molecular modeling studies, to possess IgG-binding affinity comparable to that of the B domain of Protein A. Binding of a 20-residue peptide has been substantiated experimentally by immunoprecipitation, capillary electrophoresis, and circular dichroism spectroscopic analyses.

Amino Acid Sequence↗
PubMed1999

Increased expression of epidermal fatty acid binding protein, cofilin, and 14-3-3-sigma (stratifin) detected by two-dimensional gel electrophoresis, mass spectrometry and microsequencing of drug-resistant human adenocarcinoma of the pancreas.

In order to study possible mechanisms leading to chemoresistance in pancreatic adenocarcinoma we examined the global protein expression of pancreatic cancer cells in vitro. We used a cell culture model derived from the adenocarcinoma of the pancreas (EPP85-181P). A classical multidrug-resistant subline, EPP85-181RDB, selected in presence of daunorubicin, and an atypical multidrug-resistant cell variant, EPP85-181RNOV, selected in presence of mitoxantrone, were analyzed using two-dimensional electrophoresis. After staining and image analysis, spots of interest were isolated using preparative two-dimensional electrophoresis and subjected to mass spectrometry and microsequencing. Three proteins, E-FABP, cofilin, and 14-3-3-sigma (stratifin), were overexpressed in chemoresistant cell lines. Cofilin was present in both multidrug in chemoresistant cell lines. Cofilin was present in both multidrug-resistant cell lines. E-FABP and 14-3-3-sigma (stratifin) was found to be overexpressed only in the mitoxantrone-selected atypical multidrug-resistant cell line. The possible significance of these findings is discussed.

14-3-3 Proteins↗
PubMed1999

Search for novel proteins involved in the development of chemoresistance in colorectal cancer and fibrosarcoma cells in vitro using two-dimensional electrophoresis, mass spectrometry and microsequencing.

In search of novel mechanisms that may lead to the development of chemoresistance of malignant tumors of the large bowel we used two-dimensional electrophoresis to identify proteins that were overexpressed in colorectal and fibrosarcoma cell lines that were resistant towards mitoxantrone. This cytostatic drug is known to lead to atypical multidrug resistance, i.e., the classical mechanism of multidrug resistance (MDR) accompanied by the overexpression of P-glycoprotein (P-gp) is ineffective. Using mass spectrometry and microsequencing we found adenine phosphoribosyl transferase and breast cancer specific gene 1 (BCSG1) overexpressed in the resistant colorectal tumor cell line. In the chemoresistant fibrosarcoma cell line we found two proteins that were overexpressed. One was identified as Rho-guanine dinucleotide phosphate (Rho-GDP) dissociation inhibitor and the other had sequence homologies with yeast protein yer-7. The putative role of these proteins is discussed.

Antineoplastic Agents↗
PubMed1999

Rapid detection of elevated prostate-specific antigen levels in blood: performance of various membrane strip tests compared.

OBJECTIVES: To compare the ability of four commercially available membrane strip tests to detect increased (4 microg/L or more) concentrations of prostate-specific antigen (PSA) in blood. METHODS: Serum samples with PSA concentrations less than 4 microg/L (n = 67) and from greater than 4 microg/L to 20 microg/L (n = 32) were independently examined by two observers using the PSA membrane strip tests from Chembio, Medpro, Seratec, and Syntron. The positive and negative results of each membrane strip test were classified as either true positive or negative and false negative or positive by comparing them with the quantitative PSA assay of Immulite DPC using the conventional threshold value of 4 microg/L. RESULTS: The interobserver variations of the tests were between 93% and 97%. The color stability of the Seratec and Chembio tests did not show significant differences between test results read within 10 to 20 minutes of the reaction time; however, the results of the other two tests were especially affected by variations in the reading time. The sensitivity and specificity of the tests in relation to the threshold of 4 microg/L were 67% to 93% and 87% to 97%, respectively. CONCLUSIONS: The Syntron test and, within certain limitations, the Seratec test fulfill the concept of a rapid and convenient PSA determination to detect PSA concentrations greater than 4 microg/L. Methodologic optimization of the tests by a grading of the PSA measuring ranges (eg, between 0 and 2, 3 and 4, 4 and 6, and 7 and 10 microg/L) should be taken into account for future development.

Aged↗
PubMed1999

Determination of alpha1-antichymotrypsin-PSA complex in serum does not improve the differentiation between benign prostatic hyperplasia and prostate cancer compared with total PSA and percent free PSA.

OBJECTIVES: To evaluate the analytical performance and diagnostic utility of alpha1-antichymotrypsin (ACT)-prostate-specific antigen (PSA) complex in serum to improve the differentiation between benign prostatic hyperplasia (BPH) and prostate cancer (PCa). METHODS: Serum concentrations of total PSA (tPSA), free PSA (fPSA), and ACT-PSA were measured in 112 untreated patients with PCa (median age 65 years), 34 patients with BPH (median age 66 years) with histologic confirmation, and 33 men without prostate disease and with a normal digital rectal examination considered as controls (median age 54 years). Sera were frozen at -80 degrees C within 2 hours after collection and then analyzed during a 12-week period. Determinations were made with the Enzymun-Test for tPSA and fPSA and with a prototype assay for ACT-PSA on the ES system (Roche Diagnostics, Boehringer Mannheim). RESULTS: The new ACT-PSA assay showed reliable data of analytical performance. The lower detection limit amounted to 0.068 microg/L. The assay was linear to 50 microg/L. Spiking experiments showed a mean recovery rate of 98.2%. No interferences of the assay were observed in patients with acute inflammation and highly increased ACT concentrations. The values of intra- and interassay imprecision ranged from 1.51% to 3.48% and 2.1% to 6.3%, respectively. The median value of ACT-PSA concentrations were significantly different (P <0.001) between controls and patients with BPH and PCa (0.40, 3.86, 5.26 microg/L, respectively). The median fPSA/tPSA and fPSA/ACT-PSA ratios were significantly different between BPH and PCa (24.3% versus 12.2%, P <0.001 and 32.9% versus 15.0%, P <0.001, respectively), but no difference of the ACT-PSA/tPSA ratio was observed (78.2% versus 78.7%, P = 0.696). Receiver operating characteristics of ACT-PSA (area under the curve = 0.630) and all the derivative ratios of fPSA/ACT-PSA (area = 0.737) and ACT-PSA/tPSA (area = 0.528) were not different from that of tPSA (area = 0.619), but showed a lower discrimination power between BPH and PCa than the fPSA/tPSA ratio (area = 0.790). CONCLUSIONS: Using this prototype assay to quantify ACT-PSA in serum, we have demonstrated that ACT-PSA and the calculated derivatives are not superior in the differentiation between BPH and PCa compared with tPSA and the ratio of fPSA to tPSA.

Adult↗
PubMed1999

Rapid reversal of nephrotic syndrome due to primary systemic AL amyloidosis after VAD and subsequent high-dose chemotherapy with autologous stem cell support.

In a patient with nephrotic syndrome, renal biopsy revealed AL amyloid deposits. Monoclonal lambda light chains were identified in serum and urine. A low percentage of monoclonal plasma cells was detected in the bone marrow. The patient received four cycles of VAD and subsequent high-dose chemotherapy (HDCT) with melphalan (200 mg/m2) followed by autologous peripheral blood stem cell transplantation. Proteinuria rapidly diminished during chemotherapy. Three months after HDCT, the patient has no edema, and no signs of plasma cell dyscrasia are currently detectable. Using VAD before starting HDCT may improve the condition of patients with amyloidosis and reduce transplantation-related morbidity and mortality.

Amyloidosis↗
PubMed1999

MCM21 and MCM22, two novel genes of the yeast Saccharomyces cerevisiae are required for chromosome transmission.

The minichromosome maintenance genes, MCM21 and MCM22, have been cloned and are shown to code for the ORFs YDR318W and YJR135C respectively. Mutations in these genes caused a decrease in the stability of the minichromosome. This decrease in stability was associated with an increase in the copy number of the minichromosome in cells carrying it. Small circular dicentric plasmids were maintained relatively stably and structurally intact in the mutants compared with the wild-type strain. In the latter, such plasmids were mitotically unstable and, upon recovery, showed frequent rearrangements of their DNA. A centromere offered less obstruction to transcription in mutant cells than in the wild type, showing that both these mutants had a more relaxed kinetochore assembly. The mutant strains showed elevated rates of chromosome loss but not those of recombination. Both the mutations caused the cells to display a higher sensitivity towards the anti-mitotic drug benomyl. All these observations suggest that MCM21 and MCM22 are important for chromosome segregation with a potential role in kinetochore function. These genes are non-essential, as their deletions from chromosomes did not cause loss of cell viability. However, exponentially growing mutant cells carrying the deletion of the MCM21 gene had a significant population of large-budded cells with a single nucleus at the neck. Furthermore, the DNA content of these cells showed a shift towards 2N, suggesting a temporary pause of cells in G2 or in an early phase of mitosis. The mcm21 and mcm22 mutations do not show synthetic lethality or any further enhancement of growth defects, implying that they could be carrying out non-overlapping functions in chromosome segregation.

Cell Cycle Proteins↗
PubMed1999

Radionuclide renal scan findings in rupture of the ureter: a case report.

Radionuclide renal scan findings in a patient with iatrogenic rupture of the ureter are reported. Although the literature contains reports of the radionuclide scan in rupture of the ureter from other causes, this, to our knowledge is the first description of the scan findings in iatrogenic rupture.

Aged↗
PubMed1999

Development of a unique phantom to assess the geometric accuracy of magnetic resonance imaging for stereotactic localization.

OBJECTIVE: To test the spatial accuracy of coordinates generated from magnetic resonance imaging (MRI) scans, using the Brown-Roberts-Wells head frame and localizer system (Radionics, Inc., Burlington, MA). METHODS: An anthropomorphic head phantom, consisting of a two-dimensional lattice of acrylic spheres (4-mm diameter) spaced 10 mm apart and embedded in a brain tissue-mimicking gelatin-agar gel, was constructed. The intersphere distances for the target lattice positions in MRI and computed tomographic scan sets were compared. The data sets were fused, and differences in fiducial marker and intraphantom target positions were measured. RESULTS: Intersphere distances were identical for the MRI and computed tomographic scan sets (10 +/- 0.1 mm). Differences in fiducial marker positions [maximal lateral difference, 0.97 mm; mean absolute lateral difference, 0.69 +/- 0.22 mm; maximal anteroposterior (AP) difference, 1.99 mm; mean absolute AP difference, 1.29 +/- 0.67 mm] were correlated with differences in intraphantom target positions (maximal lateral difference, 0.83 mm; mean absolute lateral difference, 0.28 +/- 0.24 mm; maximal AP difference, -1.97 mm; mean absolute AP difference, 1.63 +/- 25 mm; maximal vertical difference, -0.73 mm; mean absolute vertical difference, 0.34 +/- 0.21 mm). This suggested that improper fiducial rod identification and the subsequent transformation to stereotactic coordinate space were the greatest sources of spatial uncertainty. CONCLUSION: With computed tomographic data as the standard, these differences resulted in maximal and minimal composite uncertainties of 2.06 and 1.17 mm, respectively. The measured uncertainties exceed recommended standards for radiosurgery but allow the possible use of MRI-based stereotactic treatment planning for certain intracranial lesions, if the errors are corrected using appropriate software. Clinicians must recognize that error magnitudes vary for different systems, and they should perform systematic, scheduled, institutional error analyses as part of their ongoing quality assurance processes. This phantom provides one tool for measuring such variances.

Brain Mapping↗
PubMed1999

Lichen sclerosus of the vulva. Long-term steroid maintenance therapy.

OBJECTIVE: To assess the efficacy of graduated topical steroids for long-term maintenance therapy for vulvar lichen sclerosus. STUDY DESIGN: A prospective observational study was performed in the Gynaecological Oncology Department, City Hospital, Birmingham, U.K. Fifty-four patients were recruited for the study. The diagnosis was confirmed with histopathologic examination. After confirmation of the diagnosis, patients were started on a diminishing regimen of topical steroid. RESULTS: Of the 54 patients in the study, 51 responded to the steroid regimen, and three did not. CONCLUSION: The graduated topical steroid regimen has a high response rate and takes a relatively short time to achieve, justifying the use of graduated topical steroids for this condition. Graduated dose reduction allows the majority of patients to remain in asymptomatic remission and minimize steroid exposure.

Administration, Cutaneous↗