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S Desai

Publications and source records attributed to S Desai.

At least 55 records · Page 3Linked to original sources
PubMed2001

Ratios of multijet Cross Sections in p p collisions at radical(s) = 1.8 TeV.

We report on a study of the ratio of inclusive three-jet to inclusive two-jet production cross sections as a function of total transverse energy in p&pmacr; collisions at a center-of-mass energy sqrt[s] = 1.8 TeV, using data collected with the D0 detector during the 1992-1993 run of the Fermilab Tevatron Collider. The measurements are used to deduce preferred renormalization scales in perturbative O(alpha(3)(s)) QCD calculations in modeling soft-jet emission.

Journal Article↗
PubMed2001

Inclusive jet production in pp(macro) collisions.

We report a new measurement of the pseudorapidity (eta) and transverse-energy ( E(T)) dependence of the inclusive jet production cross section in pp(macro) collisions at square root of s = 1.8 TeV using 95 pb(-1) of data collected with the D0 detector at the Fermilab Tevatron. The differential cross section d(2)sigma/(dE(T)d eta) is presented up to eta = 3, significantly extending previous measurements. The results are in good overall agreement with next-to-leading order predictions from QCD and indicate a preference for certain parton distribution functions.

Journal Article↗
PubMed2001

Search for large extra dimensions in dielectron and diphoton production.

We report a search for effects of large extra spatial dimensions in pp collisions at a center-of-mass energy of 1.8 TeV with the D0 detector, using events containing a pair of electrons or photons. The data are in good agreement with the expected background and do not exhibit evidence for large extra dimensions. We set the most restrictive lower limits to date, at the 95% C.L. on the effective Planck scale between 1.0 and 1.4 TeV for several formalisms and numbers of extra dimensions.

Journal Article↗
PubMed2001

Proliferating cell nuclear antigen and epidermal growth factor receptor (EGFr) status in renal cell carcinoma patients with polysomy of chromosome 7.

We investigated 40 cases of renal cell carcinoma (RCC) to study the polysomy 7 status in papillary and clear-cell types (nonpapillary RCC) and relationship with clinical, pathological, and biological features such as grade, stage, tumor proliferation rate (PCNA expression) and epidermal growth factor receptor (EGFr) expression and thereby to understand the prognostic significance of polysomy 7 and EGFr expression. In a prospective study, chromosome 7 copy number was analyzed in tumor cells by using fluorescence in situ hybridization (FISH) with an alpha-satellite DNA probe for chromosome 7. Both proliferating cell nuclear antigen (PCNA) and EGFr expression were examined in paraffin sections by immunostaining. The relationship between clinicopathological and clinicobiological parameters was evaluated by appropriate statistical methods. Polysomy 7 was present in 100% of papillary and 56.2% of clear-cell types RCC. In clear-cell RCC, in comparison with polysomy 7-dominant (D) category (20-50% polysomy-7 cells), polysomy 7-major (M) category (>50% polysomy 7 cells) was associated with higher tumor grade (P = 0.05). Polysomy 7 was also correlated with stage of the disease (P = 0.006). The PCNA index ranged between 12.8-89.6% and was comparatively high in high-grade tumors (P = 0.001). The PCNA index was also correlated with polysomy 7 (P = 0.002), and the association was stronger in tumors with polysomy M versus polysomy D category (P = 0.02). The EGFr expression did not correlate with either grade, stage, PCNA, or polysomy 7. The correlation of polysomy 7 with less favorable prognostic factors such as higher tumor grade, stage, and higher proliferative index in the present study indicates that polysomy 7 might be used as a prognostic predictor in clear-cell RCC. Evaluation of clinical end points will confirm the prognostic potential of the genetic marker polysomy 7 in our study.

Adenocarcinoma, Clear Cell↗
PubMed2001

The Nudix hydrolases of Deinococcus radiodurans.

All 21 of the Nudix hydrolase genes from the radiation-resistant organism Deinococcus radiodurans have been cloned into vectors under the control of T7 promoters and expressed as soluble proteins in Escherichia coli. Their sizes range from 9.8 kDa (91 amino acids) to 59 kDa (548 amino acids). Two novel proteins were identified, each with two Nudix boxes in its primary structure, unique among all other known Nudix hydrolases. Extracts of each of the expressed proteins were assayed by a generalized procedure that measures the hydrolysis of nucleoside diphosphate derivatives, and several enzymatic activities were tentatively identified. In addition to representatives of known Nudix hydrolase subfamilies active on ADP-ribose, NADH, dinucleoside polyphosphates or (deoxy)nucleoside triphosphates, two new enzymes, a UDP-glucose pyrophosphatase and a CoA pyrophosphatase, were identified.

Amino Acid Sequence↗
PubMed2001

Pigmented epidermal cysts.

There are few reports documenting the presence of melanin or melanocytes in epidermal cysts. One hundred and twenty five epidermal cysts from Indian patients were analyzed for the presence of melanin pigment and their sites were noted. A Masson's Fontana stain and immunohistochemistry for S-100 protein and HMB 45 was performed for localization of melanin and melanocytes within the epidermal cysts. Seventy-nine (63%) of the epidermal cysts showed presence of melanin pigment or melanocytes to a variable extent. Melanin was not present in epidermal cysts occurring along lines of fusion of skin folds during embryonogenesis (e.g., ventral midline, inner canthus, nose, upper lip and in the distal most parts like leg and foot and also scrotum). Ten of the 79 epidermal cysts showed extensive accumulation of melanin pigment and infiltration with melanophages in the cyst wall. Four of these patients gave history of trauma and the follow-up was uneventful in two of them. Pigmentation of epidermal cysts thus follows a definite anatomic pattern and is dependent on the natural skin color. Large amount of pigment accumulation within epidermal cysts occurs after cyst rupture and is not associated with hemochromatosis as was believed in the past.

Adolescent↗
PubMed2001

Morphologic expressions of urothelial carcinoma in situ: a detailed evaluation of its histologic patterns with emphasis on carcinoma in situ with microinvasion.

The recently proposed World Health Organization/International Society of Urological Pathology (WHO/ISUP) consensus classification of flat urothelial lesions expands the definition traditionally used for urothelial (transitional cell) carcinoma in situ (CIS), basing its diagnosis predominantly on the severity of cytologic changes. Lesions now encompassed within the diagnosis of CIS exhibit an array of cytologic and architectural features, which have not been documented in detail. In this study, cases were examined with respect to histologic patterns and microinvasion (invasion into the lamina propria to a depth of less than 2 mm). Five major patterns of CIS, often occurring in the same specimen (160 patterns in 77 cases), were noted. Common to each pattern was the presence of high-grade cytologic atypia, the definitional feature. The patterns found include 1) large cell CIS with pleomorphism (57%), in which the cells had abundant cytoplasm and nuclear pleomorphism; 2) large cell CIS without nuclear pleomorphism (48%); 3) small cell CIS (14%), in which the cytoplasm was relatively scant and pleomorphism was usually minimal; 4) clinging CIS (40%), in which the urothelium was denuded with a patchy, usually single layer of atypical cells; and 5) cancerization of urothelium (16%) with either pagetoid spread (clusters or isolated single cells) or undermining or overriding of the normal urothelium. Carcinoma in situ with microinvasion into the lamina propria (13 cases: 3 of 77 CIS cases studied above and 10 additional cases) was evident as invasive cells with retraction artifact mimicking vascular invasion (77%, 10 cases); nests, irregular cords, and strands, or isolated single cells with desmoplasia (8%, 1 case); or absent stromal response (15%, 2 cases). Although the diagnostic terminology for all of these patterns, for the purposes of the surgical pathology report, should be simply urothelial CIS with no specific mention of the morphologic pattern, awareness of the histologic diversity of CIS will facilitate the diagnosis of this therapeutically and biologically critical flat lesion of the urothelium. These lesions may be associated with microinvasion, which may be clinically unsuspected and histologically subtle.

Carcinoma in Situ↗
PubMed2001

Discriminatory immunohistochemical staining of urothelial carcinoma in situ and non-neoplastic urothelium: an analysis of cytokeratin 20, p53, and CD44 antigens.

Distinction of urothelial carcinoma in situ (CIS) from reactive atypia on the basis of morphology alone may be difficult in some cases. Because this distinction is therapeutically and prognostically critical, we attempted to determine if an immunohistochemical panel would help in this differential diagnosis. The immunoprofile of 21 cases of CIS and 25 non-neoplastic urothelia (15 urothelial biopsies with reactive atypia from patients without a history of bladder cancer and 10 normal ureter sections from nephrectomies performed for renal cell carcinoma) was determined using antibodies against cytokeratin 20 (CK20), p53, and CD44 (standard isoform). In the normal urothelium CK20 showed patchy cytoplasmic immunoreactivity in only the superficial umbrella cell layer and CD44 stained only the basal cells. Nuclear immunoreactivity to p53 varied from negative to weak and patchy. Reactive urothelium also showed CK20 immunoreactivity in only the umbrella cell layer in all 15 cases, and p53 nuclear staining was predominantly negative with occasional weak positivity in the basal and parabasal intermediate cells. CD44 was overexpressed in the entire reactive urothelium in 9 cases (60%) or focally positive in intermediate cells in 6 cases (40%). In contrast, CIS showed intense CK20 and p53 positivity (81% and 57%, respectively) in the majority (>50%) of malignant cells. CD44 staining revealed residual basal cells with membranous reactivity in 44% of the cases of CIS; however, the neoplastic cells were immunonegative in all cases. At least one positive immunomarker (CK20 or p53) was abnormally expressed in all cases of CIS. Abnormal expression of CK20 (increased), p53 (increased), and CD44 (decreased) in urothelial CIS, and increased expression of CD44 in reactive atypia allows more confident distinction of urothelial CIS from non-neoplastic urothelial atypias. From a differential diagnosis perspective, use of a panel of all three antibodies with morphologic correlation would be essential.

Biomarkers, Tumor↗
PubMed2001

Norepinephrine modulates myelopoiesis after experimental thermal injury with sepsis.

OBJECTIVE: To determine whether thermal injury and sepsis cause an increase in bone marrow norepinephrine release and whether such a release influences bone marrow monocytopoiesis. SUMMARY BACKGROUND DATA: The authors previously demonstrated enhanced bone marrow monocytopoiesis after burn with sepsis. They also showed that physiologic stress and bacterial challenge without injury could lead to a dynamic release of norepinephrine from the bone marrow compartment. In this study, they sought to determine the potential cause-and-effect relationship of bone marrow norepinephrine release on increased monocytopoiesis after burn sepsis. METHODS: Norepinephrine release from bone marrow was determined by traditional pulse-chase methods. Tissue and bone marrow norepinephrine content was ablated by chemical sympathectomy with 6-hydroxydopamine treatment. Clonogenic potential in response to colony-stimulating factors was determined in total nucleated bone marrow cells. Dual color flow cytometry was used to document the distribution pattern of monocyte progenitors. RESULTS: Burn sepsis induced increased norepinephrine release in bone marrow, spleen, and heart. Colony-forming assays demonstrated an increase in responsive colonies, which was significantly attenuated when norepinephrine content was reduced in animals before burn sepsis. Flow cytometric analysis of early and late monocyte progenitors showed a significantly altered distribution profile of monocyte progenitors in norepinephrine-depleted mice compared with norepinephrine-intact mice. Abrogation of bone marrow norepinephrine content resulted in a 62% survival rate in burn septic mice compared with no survivors in norepinephrine-intact mice. CONCLUSIONS: These data suggest that enhanced bone marrow norepinephrine release after burn sepsis may play a role in bone marrow monocytopoiesis, thus contributing to the sustenance of inflammation.

Animals↗
PubMed2001

Detection of hypoglycemia with the GlucoWatch biographer.

OBJECTIVE: Hypoglycemia is a common acute complication of diabetes therapy. The GlucoWatch biographer provides frequent and automatic glucose measurements with an adjustable low-glucose alarm. We have analyzed the performance of the biographer low-glucose alarm relative to hypoglycemia as defined by blood glucose < or = 3.9 mmol/l. RESEARCH DESIGN AND METHODS: The analysis was based on 1,091 biographer uses from four clinical trials. which generated 14,487 paired (biographer and blood glucose) readings. RESULTS: The results show that as the low-glucose alert level of the biographer is increased, the number of true positive alerts (alarm sounds and blood glucose < or = 3.9 mmol/l) and false positive alerts (alarm sounds but blood glucose >3.9 mmol/l) increased. When analyzed as a function of varying low-glucose alert levels, the results show receiver operator characteristic curves consistent with a highly useful diagnostic tool. Setting the alert level from 1.1 to 1.7 mmol/l above the level of concern is likely to optimize the trade-off between true positives and false positives for each user. When the same blood glucose data are analyzed for typical monitoring practices (two or four measurements per day), the results show that fewer hypoglycemic events are detected than those detected with the biographer.

Automation↗
PubMed2001

Nerve cell markers in ossifying fibromyxoid tumour of soft parts.

Reported herein are two benign ossifying fibromyxoid tumors (OFMTs) of the soft tissues in axilla and terminal phalanx respectively. Both cases on immunohistochemistry (IHC) showed reactivity for vimentin, S-100 protein and glial fibrillary acidic protein (GFAP) antibodies. In addition, a focal/diffuse strong positivity for neurofilament (NF) and neuron specific enolase (NSE) was observed. Electron microscopy in one instance revealed abundant intermediate filaments, primitive cell junctions and a focally present external lamina. In the light of nerve cell differentiation of these tumors and the similarity of IHC profile and EM features of OFMT to a poorly differentiated malignant peripheral nerve sheath tumor (MPNST); it is suggested that OFMT is a variably differentiated PNST rather than a simple Schwannian neoplasm as is believed.

Adult↗
PubMed2000

Unwinding of a DNA triple helix by the Werner and Bloom syndrome helicases.

Bloom syndrome and Werner syndrome are genome instability disorders, which result from mutations in two different genes encoding helicases. Both enzymes are members of the RecQ family of helicases, have a 3' --> 5' polarity, and require a 3' single strand tail. In addition to their activity in unwinding duplex substrates, recent studies show that the two enzymes are able to unwind G2 and G4 tetraplexes, prompting speculation that failure to resolve these structures in Bloom syndrome and Werner syndrome cells may contribute to genome instability. The triple helix is another alternate DNA structure that can be formed by sequences that are widely distributed throughout the human genome. Here we show that purified Bloom and Werner helicases can unwind a DNA triple helix. The reactions are dependent on nucleoside triphosphate hydrolysis and require a free 3' tail attached to the third strand. The two enzymes unwound triplexes without requirement for a duplex extension that would form a fork at the junction of the tail and the triplex. In contrast, a duplex formed by the third strand and a complement to the triplex region was a poor substrate for both enzymes. However, the same duplex was readily unwound when a noncomplementary 5' tail was added to form a forked structure. It seems likely that structural features of the triplex mimic those of a fork and thus support efficient unwinding by the two helicases.

Binding Sites↗
PubMed2000

Changes in lipoprotein(a) concentration after orthotopic heart transplantation.

BACKGROUND: Elevated concentrations of lipoprotein(a) have been considered an important risk factor in the development of premature cardiovascular disease and have been proposed as a risk factor in the development of accelerated cardiac allograft vasculopathy after orthotopic heart transplantation. METHODS: We prospectively measured lipoprotein(a), fasting cholesterol, and triglyceride concentrations before (n = 38), 6 months (n = 38), and 1 year (n = 21) after orthotopic heart transplantation. The mean age of the patients was 52 +/- 2 years. Eighty-seven percent of the patients were men, 82% were white, and 61% had ischemic cardiomyopathy. RESULTS: Mean lipoprotein(a) concentration was lower 6 months after transplantation than it was before the operation (23 +/- 3 mg/dL vs 17 +/- 3 mg/dL; P =.014) and remained low 1 year after transplantation (23 +/- 3 mg/dL vs 18 +/- 4 mg/dL; P = not significant). In contrast, mean cholesterol concentration was higher 6 months after transplantation (171 +/- 8 mg/dL vs 221 +/- 8 mg/dL; P <.001) and 1 year (171 +/- 8 mg/dL vs 205 +/- 10 mg/dL; P <.01) than it was before transplantation. Triglyceride concentration was higher 1 year after transplantation than it was before the operation (146 +/- 13 mg/dL vs 184 +/- 20 mg/dL; P =.017). CONCLUSIONS: Lipoprotein(a) concentrations decrease during the 6 months after transplantation and stay low for at least 1 year after the operation. Additional studies are needed to ascertain the effect these changes in lipoprotein(a) concentration on the development of cardiac allograft vasculopathy.

Adolescent↗
PubMed2000

Modulation of metastasis phenotypes of non-small cell lung cancer cells by 17-allylamino 17-demethoxy geldanamycin.

BACKGROUND: Cancer cells that overexpress c-erbB oncogenes exhibit resistance to chemotherapy, enhanced tumorigenicity, as well as increased propensity for metastasis. The aim of this study was to investigate if depletion of erbB-1/EGFR and erbB-2/HER2neu oncogene products by 17-allylamino 17-demethoxy Geldanamycin (17AAGA) could diminish the metastatic potential of non-small cell lung cancer (NSCLC) cells that express varying levels of the erbB1/erbB2 oncogenes. METHODS: NSCLC cell lines (H460, H358, H322, or H661) were assayed for expression of erbB1 and erbB2, the cell adhesion molecule E-cadherin, secretion of the matrix metalloproteinase 9 (MMP-9), and vascular endothelial cell growth factor (VEGF), as well as their ability to invade Matrigel after 48-hour exposure to 17AAGA. RESULTS: 17AAGA significantly depleted erbB1 or erbB2 levels in NSCLC cells expressing high levels of these proteins, and effectively inhibited their growth with IC50 values ranging from 50 to 90 nmol/L. Moreover, drug treatment enhanced E-cadherin expression in H322 and H358 cells, and inhibited secretion of MMP-9 and VEGF secretion by tumor cells. 17AAGA diminished hypoxia-induced upregulation of VEGF expression as well as growth factor-mediated augmentation of MMP-9 secretion, and profoundly inhibited the ability of H322 and H358 cells to migrate through Matrigel in response to chemoattractants. CONCLUSIONS: In addition to its known antiproliferative and chemosensitization effects, 17AAGA inhibits the metastatic phenotype of lung cancer cells. 17AAGA may be a novel pharmacologic agent for specific molecular intervention in lung cancer patients.

Benzoquinones↗