PubMed Health⌕ Search

Biomedical subjects

S Mathew

Publications and source records attributed to S Mathew.

At least 37 records · Page 2Linked to original sources
PubMed1999

Comparison of cytogenetics, Southern blotting, and fluorescence in situ hybridization as methods for detecting MLL gene rearrangements in children with acute leukemia and with 11q23 abnormalities.

Bone marrow samples from 67 children with acute leukemia and with cytogenetic evidence of chromosome 11 band q23 (11q23) abnormalities were characterized by fluorescence in situ hybridization (FISH) and Southern blot analysis to determine whether FISH could reliably detect MLL gene rearrangements in this population. Among the 42 patients with acute lymphoblastic leukemia (ALL), MLL gene rearrangements were detected in cells from 23 patients (54.8%) by both FISH and Southern blot analysis. FISH identified allelic deletions of MLL gene in five of 12 patients (42%) with ALL and with deletion of 11q23. In 22 of 25 children (88%) with AML, FISH detected MLL gene rearrangements, whereas Southern blot analysis identified rearrangements in 24 of 25 patients (96%). For children with acute leukemia and with 11q23 abnormalities, we recommend that FISH be used for the rapid screening of MLL gene rearrangements and that Southern blot analysis be used for the definitive assessment of the MLL gene status.

Acute Disease↗
PubMed1999

Phaeochromocytoma: experience from a referral hospital in southern India.

BACKGROUND: Phaeochromocytoma has been traditionally called the 'Tumour of Tens'. Many investigators have reported the prevalence of extra-adrenal phaeochromocytoma to be more than 10%. METHODS: All consecutive adult patients diagnosed to have phaeochromocytoma by the departments of endocrinology and surgical endocrinology of the Christian Medical Hospital, India, over a period of 10 years from 1988 to 1998, were included in the study. RESULTS: A total of 30 patients were diagnosed to have phaeochromocytoma. Extra-adrenal phaeochromocytoma accounted for 26.6% of cases, Ten per cent of cases were bilateral, 6.6% were malignant and one patient had a familial tumour (multiple endocrine neoplasia IIB). The tumours were localized pre-operatively in all patients. Multicentric extra-adrenal tumours were not found in this series. All patients except one were explored by the anterior transperitoneal approach. Persistent hypertension was noted in 30% of patients. CONCLUSIONS: Our series shows a higher prevalence (26.6%) of extra-adrenal tumours than the traditionally described 10%. With accurate pre-operative localization, a transperitoneal approach may not be necessary. The laparoscopic approach needs to be evaluated in light of these findings.

Adrenal Gland Neoplasms↗
PubMed1999

Implicit memory for phonological processes in visual stem completion.

Four experiments were conducted investigating the role of phonology in repetition priming. Experiment 1 used a cross-modal priming paradigm in which participants made semantic judgments about spoken words and then performed a visual stem completion task. In Experiments 2-4, both the primes and the test stems were presented visually. The results of the first three experiments revealed that priming transfers across interpretations of a homophone. That is, seeing or hearing week primes both week and weak. The results of Experiment 4 showed that homophone priming cannot be attributed to the orthographic similarity of homophonic words. Together, these results indicate that repetition priming on a visual word completion task includes a phonological component.

Adult↗
PubMed1999

Early results from indirect drug susceptibility test for tubercle bacilli.

The indirect susceptibility test results on L-J medium for tubercle bacilli against streptomycin, isoniazid and rifampicin were read at the end of 2 wk and compared with the results at 4 wk. It was found that drug resistance could be correctly predicted in over 70 per cent of cultures including multi-drug resistant tuberculosis (MDR TB) strains at the end of 2 wk. The susceptibility to para-nitrobenzoic acid (PNB) read at 2 wk was able to distinguish non-tuberculous mycobacteria from Mycobacterium tuberculosis cultures. The early detection of resistance by this procedure requires only minimum inputs, and can benefit the majority of patients harbouring drug resistant tubercle bacilli.

Antitubercular Agents↗
PubMed1998

A human lymphoid leukemia cell line with a V(D)J recombinase-mediated deletion of hprt.

Large deletions of exons 2 and 3 of the hprt gene are the most common type of hprt mutation in lymphocytes of newborn infants, and their frequency increases in cultured human T-lymphoid cells as a result of exposure to etoposide. Sequenced PCR products for these deletions are consistent with a V(D)J recombinase-mediated mechanism underlying their genesis. Herein, we describe the isolation and characterization of an etoposide-induced mutant CEM cell line that is clonal for a V(D)J recombinase-mediated exon 2 + 3 deletion. Human CCRF-CEM cells were exposed to 5 muM etoposide for 4 h, selected in 6-thioguanine, and an exon 2 + 3 deletion mutant was isolated through serial limiting dilution, using a PCR-based assay for detection of the exon 2 + 3 deletion. Untreated CEM cells and cells treated with 6-thioguanine alone were similarly subcultured. The exon 2 + 3 deletion-containing line was termed SJCEM808 and had a slightly longer doubling time than the control lines, tended to clump in suspension, and was characterized by cell membrane blebbing. Compared to the parent line, SJCEM808 had similar cytogenetic abnormalities, lower CD2, CD1, and CD10 expression, and negligible RAG-1 expression. However, RAG-1 expression was down-regulated in some untreated parental subclones following similar subculturing. The sequence of the exon 2 + 3 deletion mutation exhibited nucleotide insertions, and the breakpoints were adjacent to heptamer signal recognition sequences in intact hprt, consistent with a V(D)J recombinase-mediated mechanism underlying its genesis. There were no MLL gene or interlocus T-cell receptor (TCR) rearrangements. These results indicate that non-homologous recombination following etoposide treatment is neither necessarily accompanied by other large DNA rearrangements nor simply a pre-lethal event, and this cell line may serve as a useful tool for studying illegitimate V(D)J recombinase-mediated deletions.

Antigens, Surface↗
PubMed1998

Pentoxifylline potentiates in vitro lymphocyte suppression by glucocorticoids and immunosuppressive drugs.

Pentoxifylline, which has immunomodulatory effects in addition to its better known rheologic effects, might potentiate the effectiveness of traditional immunosuppressive drugs. We therefore studied the suppressive effect of pentoxifylline in combination with clinically relevant concentrations of prednisolone, methylprednisolone, cyclosporine, tacrolimus, rapamycin, and mycophenolic acid on mitogen-stimulated lymphocytes from 29 patients with glomerular diseases. Inhibition of lymphocyte proliferation obtained with 10(-7) and 10(-8) mol/L concentrations of the glucocorticoids and with 300 ng/mL cyclosporine was significantly increased when each was combined with 5, 25, or 50 microg/mL of pentoxifylline. The additive inhibitory effect of pentoxifylline in combination with 10(-7) mol/L glucocorticoids was inversely proportional to the inhibitory effect of the 10(-7) mol/L concentration of glucocorticoid alone, suggesting that the less sensitive the patient's cells, the greater the potentiation by pentoxifylline. The greatest degree of potentiation by pentoxifylline occurred when combined with the lower (10(-8) mol/L) concentration of glucocorticoids. Pentoxifylline also significantly increased lymphocyte suppression in combination with 150 and 300 ng/mL concentrations of cyclosporine, 5 ng/mL of tacrolimus, 2.5 x 10(-7) mol/L mycophenolic acid, and 10 ng/mL of rapamycin. These in vitro results suggest that pentoxifylline might have steroid-sparing effects and contribute to improved clinical outcomes from immunosuppressive treatment of renal diseases.

Adult↗
PubMed1998

Atelectasis in children.

BACKGROUND: In children with lower respiratory tract symptoms, the elicited signs are not enough to distinguish common diagnosis like pneumonic consolidation, foreign body aspiration and atelectasis. Radiology and bronchoscopy would identify the true nature of the etiology. DESIGN: Prospective study. SUBJECTS: Thirty five children with both acute and chronic lower respiratory tract symptomatology, were analyzed for clinical and radiological signs of atelectasis. RESULTS: There were 23 cases in the acute group and 12 in chronic group. Acute group included cases of pneumonia, foreign body aspiration and mucus plug syndrome. Chronic group included cases of congenital heart disease, endobronchial tuberculosis and bronchial stenosis. Clinical recognition of atelectasis on the basis of localized loss of breath sounds and mediastinal shift was seen only in a minority of cases (8/35). The presence of atelectasis in children with pneumonia, missed clinically were diagnosed by the presence of tracheal shift, elevated hemidiaphragm and silhouette sign. In 21 cases, silhouette sign was positive making it an important radiological sign. Twenty one children underwent either diagnostic or/and therapeutic bronchoscopy. Findings included foreign bodies (n = 5), mucus plugs (n = 4), narrowing of main bronchus (n = 4) and inflammatory mucoid secretions and narrowing of lumen (n = 8). There were no major complications. CONCLUSION: The diagnosis of atelectasis in children may pose difficulties and there is a need to have a high index of suspicion to exclude atelectasis in children with either acute or chronic respiratory tract symptomatology.

Acute Disease↗
PubMed1998

Role of pinaverium bromide in south Indian patients with irritable bowel syndrome.

The effect of pinaverium bromide in controlling gastrointestinal symptoms in 61 patients with irritable bowel syndrome was studied, as an open trial. Individually, there was significant relief in abdominal discomfort/pain as well as in bowel symptoms in most of the patients. Abdominal pain was reduced in 49%, stool consistency improved in 74%, straining and urgency decreased in 71% and mucus decreased in 64%. Tolerance to the drug administered was good and side-effects reported were few.

Adult↗
PubMed1998

Modulation of biochemical activity of hepatocytes in culture by matrix substratum.

The influence of extra cellular matrix on the biochemical activity of hepatocytes was studied by maintaining rat hepatocytes in primary culture in a serum free medium on different matrix protein substrata or biomatrices prepared from liver, aorta or mammary gland. There was significant difference in the individual protein synthesis and distribution by cells maintained on different substrata. Comparison of the kinetics of synthesis and secretion of albumin by cells maintained on different tissue biomatrix showed that those maintained on hepatic biomatrix synthesized more albumin and retained more of albumin synthetic capacity, when compared to those maintained on aortic and mammary gland biomatrix. Similarly, hepatocytes maintained on hepatic biomatrix synthesized significantly more apo B, the major apo protein of VLDL, than those maintained on heterologous tissue matrix. Induction of tyrosine aminotransferase by dexamethasone and the uptake of [14C]-amino isobutyric acid were found to be maximum in cells maintained on liver biomatrix than the heterologous biomatrix. But cells maintained on hepatic biomatrix incorporated less amounts of radioactivity into total cytoskeletal proteins as well as the individual proteins such as actin and the cytokeratins C8 and C18 while that by cells maintained on aortic biomatrix was significantly high. Quantitative analysis of the relative incorporation of radioactivity into individual cytoskeletal proteins and albumin in pulse labelling studies with cells maintained in culture on different matrix for different lengths of time revealed a reciprocal relationship between these two activities. These results indicate that the substrata with which the cells are in contact influence on a selective basis, the biochemical activity of hepatocytes in primary culture.

Albumins↗
PubMed1997

12p abnormalities and the TEL gene (ETV6) in childhood acute lymphoblastic leukemia.

Although abnormalities involving the short arm of chromosome 12 (12p) are one of the most frequently observed rearrangements in childhood acute lymphoblastic leukemia (ALL), little is known about the frequency of different structural abnormalities and their relationship to the status of the ETV6 (also named TEL) gene in this region. Of 815 children with newly diagnosed ALL, 94 (11.5%) had a total of 104 cytogenetic 12p abnormalities. Loss of genetic material was observed in 67 (64%) of these abnormalities. Cases with 12p alterations had a much lower frequency of hyperdiploidy greater than 50 (7%) than did the ALL population in general, but these cases had a similar distribution of immunophenotype and similar 5-year event-free survival (70% +/- 5% SE v 64% +/- 2%, P = .64). Rearrangement of the ETV6 gene was identified in 36 (56%) of 64 cases evaluated. The ETV6-CBFA2 (TEL-AML1) fusion transcript was found in 25 (66%) of 38 cases evaluated, and all but one of these showed ETV6 rearrangement. Importantly, ETV6 rearrangement was associated with a favorable prognosis (5-year event-free survival: 89% +/- 6% v 60% +/- 1%, P < .01). We conclude that most but not all 12p cytogenetic abnormalities in childhood ALL involve ETV6, and that rearrangement of ETV6 is associated with a favorable treatment outcome.

Adolescent↗
PubMed1997

Pulmonary sequestration--a diagnostic pitfall: a case report.

Pulmonary sequestration is defined as a congenital malformation of abnormal lung tissue that does not communicate with the airway system and that receives blood supply from anomalous arteries. The majority of these sequestrations are encountered in the pediatric population. Surgical excision is the treatment of choice, with excellent prognosis. We studied a case of an extralobar pulmonary sequestration in a young adult, presenting as an intrathoracic mass; it was aspirated twice, final diagnosis being rendered after surgical resection. The cytologic findings and the accompanying diagnostic difficulties to our knowledge have never been reported.

Adult↗
PubMed1997

Parotid fine-needle aspiration: a cytologic study of pediatric lesions.

Fine-needle aspiration (FNA) of parotid lesions in the pediatric age group presents interesting diagnostic problems. There is limited cytologic literature available on the subject. We studied the cytologic findings on FNA of parotid masses in seven such cases. Patients ranged in age from 1 to 17 years (mean = 10.4). Diagnoses included lymphoepithelial cyst (n = 1), mucoepidermoid carcinoma (n = 2), pilomatrixoma (n = 1), acinic-cell carcinoma (n = 1), rhabdomyosarcoma (n = 1), and Ewing's sarcoma (n = 1). Six cases were confirmed by subsequent histologic examination. The study elaborates on the cytologic features of each lesion and discusses the differential diagnosis of closely related entities peculiar to this age group. It highlights the role of FNA as the diagnostic modality of choice in dealing with pediatric parotid masses.

Adolescent↗
PubMed1997

Classically conditioned changes in plasma cortisol levels induced by dexamethasone in healthy men.

Animal research has indicated that the activity of the hypothalamic-pituitary-adrenal axis can be influenced by classical (Pavlovian) conditioning procedures. To test the hypothesis that alterations in plasma cortisol levels can be conditioned in humans, the present study used a prospective, randomized, double-blind, placebo-controlled design in which a distinctively flavored beverage was paired with p.o. administration of dexamethasone. Twenty-five healthy men were randomly assigned to one of two groups. During the conditioning phase of the study, subjects in the experimental group received three conditioning trials (pairings of a distinctively flavored beverage with a capsule containing 5 mg dexamethasone) separated by 1 wk recovery periods. Subjects in the control group were treated identically, except that the capsule contained a placebo. During the test phase, all subjects underwent a test day (reexposure to the distinctively flavored beverage before receiving a placebo capsule) and a comparison day (no exposure to the beverage or the capsule). Plasma cortisol was assessed repetitively before and after administration of the beverage and capsule, as were possible confounding factors, including: behavioral variables, psychological distress, aversive reactions to the beverage, and expectations of treatment. After reexposure to the beverage and administration of a placebo capsule (conditioned stimuli), the experimental group had significantly higher levels of plasma cortisol than the control group, after controlling for variability in baseline levels of cortisol (F(5,60)=3.09; P=0.015) that could not be explained by differences in other study variables. No differences in cortisol levels were found on the comparison day. These results support the study hypothesis that changes in plasma cortisol levels can be classically conditioned in humans by pairing a distinctive beverage with p.o. administration of dexamethasone.

Adult↗
PubMed1997

Significance of peritoneal washings in gynecologic oncology. The experience with 901 intraoperative washings at an academic medical center.

OBJECTIVE: Peritoneal washings are routinely performed during gynecologic surgery. The presence or absence of malignant cells in washings helps determine the stage of the malignancy. However, the efficacy of this procedure has not been studied recently. DESIGN: All intraoperative washings for gynecologic disease at our hospital from 1992 through 1994 (901 cases) were reviewed. Of these, 380 were gynecologic malignancies that were reviewed for changes in staging based on the presence of malignant cells. RESULTS: Histologically, 380 cases were gynecologic malignancies, 521 benign, 79 nongynecologic, and 25 had no accompanying surgical pathology. Of the malignancies, 125 had a diagnosis of cancer on washings. In 12 cases (3.1%), a change in stage resulted. CONCLUSIONS: In a small but significant number of cases, malignant cells in the washings changed postoperative staging, impacting therapeutic measures and prognosis for these patients greatly. Peritoneal washings remain a simple yet effective tool in the evaluation and management of gynecologic malignancies.

Ascitic Fluid↗
PubMed1997

Antioxidant activity of Tinospora cordifolia and its usefulness in the amelioration of cyclophosphamide induced toxicity.

Extract of Tinospora cordifolia has been shown to inhibit the lipid peroxidation and superoxide and hydroxyl radicals in vitro. Concentration needed for 50% inhibition was 6 mg and 12.5 mg/ml, respectively. The extract was also found to reduce the toxic side effects of cyclophosphamide administration (25 mg/kg b.wt, 10 days) in mice hematological system by the free radical formation as seen from total white blood cell count, bone marrow cellularity and alpha-esterase positive cells. Moreover, administration of the extract partially reduced the elevated lipid peroxides in serum and liver as well as alkaline phosphatase and glutamine pyruvate transaminase. This indicates the use of Tinospora extract in reducing the chemotoxicity induced by free radical forming chemicals.

Animals↗