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M Banerjee

Publications and source records attributed to M Banerjee.

At least 19 recordsLinked to original sources
PubMed2001

Absorption spectroscopic study of EDA complexes of.

[70]Fullerene has been shown to form 1:1 molecular complexes with toluene, p-xylene, m-xylene, 1,2,4,5-tetramethyl benzene (durene) and pentamethyl benzene (PMB) in CCl4 medium by absorption spectroscopic method. Isosbestic points have been detected in case of complexes with PMB and durene. Charge transfer absorption band could not be detected but the intensity of the broad absorption band of C70 in CCl4 decreases systematically with increase in the concentration of the added methylbenzenes. From this trend the formation constants (Kc) of the complexes have been determined at three different wavelengths. The constancy of Kc with respect to change in the wavelength of measurement supports the view that complex of a single stoichiometry (1:1) is formed in each case.

Benzene Derivatives↗
PubMed2001

Biochemical recurrence after radical prostatectomy in black and white American men with a positive or negative family history of prostate cancer.

PURPOSE: We investigated the impact of a family history of prostate cancer on predicting biochemical recurrence in black and white American men. MATERIAL AND METHODS: Between January 1991 and December 1996, 910 men underwent radical retropubic prostatectomy for clinically localized prostate cancer, of whom 676 had data available on prostate cancer family history. Statistical analysis was performed to identify any correlation among the known predictors of biochemical outcome and family history in each race. RESULTS: Median followup was 34 months (range 2 to 103). We identified 355 (52%) and 321 (48%) white and black American men, respectively, for whom data were available on prostate cancer family history, including 177 (26%) with a positive and 499 (74%) with a negative history. Family history was positive in 94 black (29%) and 83 white (23%) men. No significant difference was noted in the incidence of familial prostate cancer in the 2 races (p = 0.10). In black men the biochemical failure rate was 32% and 26% in those with a positive and negative history (log rank test p = 0.51), while in white men the rate was 17% and 18%, respectively (log rank test p = 0.79). A family history positive for prostate cancer was not associated with biochemical failure in either race. CONCLUSIONS: Biochemical recurrence was not significantly worse in patients with a family history of prostate cancer than in those with nonfamilial disease in either race.

Black People↗
PubMed2001

Clearance of filtered fluid from the lung during exercise: role of hyperpnea.

During strenuous exercise in sheep, lung lymph flow increases within seconds and rises to levels 7- to 10-fold over baseline. Concomitant with the flow increase, the lymph protein content rapidly decreases to levels consistent with severe capillary hypertension. This pattern of clearance of filtered fluid is quite different than is seen with the passive capillary hypertension that results from mechanical obstruction of the mitral valve. In passive capillary hypertension, the increase in lymph flow and reduction in lymph protein content develop over several hours. The purpose of this study was to discover if these observed differences in edema clearance are related to the hyperpnea that accompanies exercise. Sheep were instrumented for continuous measurement of pulmonary arterial, left atrial, and systemic pressures, cardiac output by ultrasound, lung lymph flow, and ventilation. First, hemodynamics, ventilatory, and lymph clearance variables were measured during moderate exercise at 2.8 mph on a treadmill. Second, on a separate occasion, sheep were induced to hyperventilate to the same minute ventilation as during exercise, using modest CO2 stimulation. Lymph flow and hemodynamics were unaffected by this hyperpnea. The third arm of the experiment was to raise pulmonary microvascular pressure at rest to the level seen with exercise by means of a balloon catheter placed in the mitral valve. Lymph flow rose and protein content decreased slowly and to a lower degree than seen with exercise despite a comparable microvascular pressure. Finally, left atrial hypertension and induced hyperpnea were combined in sheep at rest, and the resulting lymph flow and protein content were the same as seen with exercise at similar pressures and ventilation. We conclude that hyperpnea is a major mechanism of interstitial liquid clearance during exercise, and may be largely responsible for preventing pulmonary edema that might occur at the high microvascular pressures of strenuous exercise.

Animals↗
PubMed2000

Gleason score 7 prostate cancer: a heterogeneous entity? Correlation with pathologic parameters and disease-free survival.

OBJECTIVES: Gleason score 7, in different proportions of grades 3 and 4, is the score most frequently assigned to prostate cancer in our radical prostatectomy specimens (RPSs). We correlated the major grade component of score 7 tumors with clinicopathologic parameters and disease-free survival. METHODS: All Gleason score 7 RPSs were classified as having a major grade of 3 or 4 carcinoma. The two groups were compared according to patient age, race, serum prostate-specific antigen (PSA) level, clinical and pathologic stage, tumor volume, and biochemical recurrence. RESULTS: Of the 534 patients analyzed, 356 and 178 had major grade 3 or 4 tumors, respectively. Compared with patients with 3+4 tumors, those with 4+3 had significantly more advanced clinical and pathologic stages, larger tumor volume, higher preoperative PSA levels, and older age and a higher proportion were African American (P <0.05 for all above parameters). With a mean follow-up of 34.6 months, patients with 3+4 tumors experienced lower rates of PSA recurrence than did those with 4+3 tumors (P = 0.0021). Furthermore, for the subset of patients with organ-confined disease, multivariable analysis that included race, age, clinical stage, preoperative PSA level, tumor volume, and major grade component found only the latter to be a significant predictor of recurrence, with patients who had major grade 4 component tumors experiencing a higher incidence of PSA recurrence than those with major grade 3 tumors (P = 0.012). CONCLUSIONS: The major grade 4 component in Gleason score 7 carcinoma indicates a higher likelihood of biochemical recurrence, particularly for the increasing proportion of patients with organ-confined disease after radical prostatectomy.

Aged↗
PubMed2000

Recursive partitioning for prognostic grouping of patients with clinically localized prostate carcinoma.

BACKGROUND: Patients treated with radical prostatectomy for clinically localized prostate carcinoma present considerable heterogeneity in terms of disease free survival outcome. Multiple studies have attempted to create prognostic groupings of these patients in the perioperative phase, using information available regarding several clinicopathologic variables. Such groupings allow physicians to make early yet prudent decisions regarding adjuvant combination therapies. The current study presents results from a statistical analysis that enables the natural identification of such prognostic groups. METHODS: Examination of consecutive radical prostatectomy specimens was performed between January 1991 and December 1995 at Wayne State University, Harper Hospital, Detroit, Michigan. Disease free survival in a cohort of 485 of these men was analyzed using recursive partitioning and amalgamation technique. Clinicopathologic parameters evaluated included age, race, preoperative prostate specific antigen (PSA) level, clinical and pathologic stage, and Gleason grade of the fine-needle biopsy as well as the radical prostatectomy specimen. RESULTS: A binary decision tree representation was generated for classifying patients based on the clinicopathologic variables mentioned earlier. The worst prognosis was for patients with either advanced stage and a PSA level > 24.1 ng/mL or advanced stage, a PSA level </= 24.1 ng/mL, and age </= 65 years. This group had an estimated median disease free survival of only 10.3 months. Patients with lower pathologic stage, prostatectomy Gleason scores of </= 7, and a preoperative PSA level </= 22.7 ng/mL had the best prognosis. CONCLUSIONS: The recursive partitioning analyses allows easy characterization of a patient for prognosis shortly after radical prostatectomy. This will enable a physician to make more prudent decisions regarding whether to employ watchful waiting, proceed with accepted adjuvant therapy (radiotherapy or hormonal therapy), or refer patients to a research center that is able to administer experimental adjuvant therapy. [See editorial counterpoint on pages 232-3 and reply to counterpoint on pages 234-5, this issue.]

Adult↗
PubMed2000

Immunohistochemical analysis of ageing human B and T cell populations reveals an age-related decline of CD8 T cells in spleen but not gut-associated lymphoid tissue (GALT).

It is thought that senescence of the immune system is responsible, at least in part, for many health problems associated with ageing. Previous studies on changes in lymphocyte composition have used flow cytometry to study peripheral blood lymphocytes (PBL's), or cells isolated from rodent tissue, and have yielded conflicting results. We have used immunohistochemistry to determine whether the B and T cells in human tissue from spleen and gut are affected by age. Areas of germinal centre, mantle zone and marginal zone of B cell follicles were measured. In addition, CD4 and CD8 T cells in T cell areas and in B cell follicles were counted. We observed a striking age-related decrease in the proportion of CD8+ T cells in the T cell zones of the spleen. This decrease was not apparent in the T cell population that occupies splenic B cell areas, or in GALT. Further differences, in CD4+ cells, were seen between T cell populations in the T cell zones and those in B cell areas. These findings highlight differences between lymphocyte populations in different lymphoid tissues, and different compartments within each tissue, which may be of importance in future studies of the ageing immune system.

Adolescent↗
PubMed2000

Phosphatase Activities of Endolithic Communities in Rocks of the Antarctic Dry Valleys.

Phosphorus is scarce in Beacon Sandstone of the McMurdo Dry Valleys, Antarctica, and any input from precipitation is minimal. In endolithic microbial communities recycling of P by the action of phosphatases may therefore be important. The phosphatase activities of three different types of endolithic communities in the McMurdo Dry Valley, Antarctica, were studied in the laboratory. The dominant phototrophs were Chroococcidiopsis, mixed Gloeocapsa and Trebouxia, and Trebouxia. Bacteria were also visually conspicuous in the latter two communities, and the Trebouxia in both cases formed a lichenized association with fungal hyphae. In each case marked phosphomonoesterase (PMEase) activity was found in assays with 4-methylumbelliferyl phosphate (MUP) or p-nitrophenyl phosphate as substrate, and phosphodiesterase activity with bis-p-nitrophenyl phosphate as substrate. The pH optimum of PMEase (assayed at 0.5 pH intervals) of the Chroococcidiopsis, Gloeocapsa-Trebouxia, and Trebouxia communities was 9.5, 5.5, and 8.0, respectively. These values are similar for aqueous extracts of the respective rocks (pH 9.2, 6.2, 7.5). All three communities showed significantly higher PMEase activity at 5 degrees than 1 degrees C, and the first two also showed much higher activity at 5 degrees than 10 degrees C. All three communities also showed slightly lower activity in the light (7 µmol photon m(-2) s(-1)) than the dark; this was found with all substrates and substrate concentrations. Prior exposure of a moistened sample to light for 2 h led to a reduction in activity even when the subsequent assay was done in the dark. The rate of PMEase activity (using 100 µM MUP) in the Gloeocapsa-Trebouxia and Trebouxia communities was approximately linear with time up to 24 h, whereas the Chroococcidiopsis community showed a marked decrease after 6 h. At least part of this was due to retention of the 4-methylumbelliferone (MU) hydrolysis product. In spite of the assays being conducted on a whole community, the activity-substrate relationship in each case quite closely resembled a typical Michaelis-Menten relationship. Estimates were made of the apparent half-saturation value and the concentration of MUP required to support half-maximal rates. The apparent K (m) values were: Chroococcidiopis, 230 µM; Gloeocapsa-Trebouxia 169 µM; Trebouxia, 135 µM. The respective values for apparent V (max) were 0.053, 0.55, and 0.35 µmol MU g(-1) h(-1). In view of the greater dependence of these communities on the rock for their sole supply of P than for C and probably N, it is suggested that the cycling of P within the communities is a key factor influencing their overall metabolic activity when moisture permits their activation. </hea

Journal Article↗
PubMed2000

Prostate cancer biochemical recurrence stage for stage is more frequent among African-American than white men with locally advanced but not organ-confined disease.

OBJECTIVES: To determine whether outcome differences between African-American men (AAM) and white men with prostate cancer (PCa) will still be present if we control for stage in a large cohort of men. It is well established that AAM have a worse outcome from PCa than white men. METHODS: We examined 848 consecutive patients who underwent radical prostatectomy at Wayne State University, Karmanos Cancer Institute, between 1991 and 1995. The mean follow-up was 34 months (range 1.5 to 75). We included men with Gleason score 7 (4 + 3) with those men with Gleason score 8 to 10 for racial/ethnic comparisons. RESULTS: AAM and white men diagnosed with organ-confined PCa demonstrated similar prostate-specific antigen (PSA) levels, Gleason grade, and biochemical recurrence. However, AAM diagnosed with non-organ-confined disease demonstrated higher PSA levels and a higher incidence of recurrence than did white men with non-organ-confined disease. There was a trend toward AAM having a greater proportion of high-grade lesions than white men when PCa was not organ confined. The evidence suggests that the difference in recurrence among AAM versus white men is based on pretreatment PSA, grade, extracapsular extension, and positive surgical margins. Seminal vesicle invasion predicted a worse prognosis equally for both AAM and white men. CONCLUSIONS: A difference in biochemical recurrence was not detected between AAM and white men with organ-confined PCa after radical prostatectomy. PSA was higher in AAM than in white men with pathologically locally advanced PCa, and the biochemical recurrence was greater. AAM had a greater percentage of high Gleason grade lesions compared with white men, and this difference approached statistical significance. We hypothesize that AAM have a more rapid growth rate of PCa, which may be responsible for these clinical findings. Further investigations of the biology of PCa are needed to understand these findings.

Black or African American↗
PubMed2000

Genetic analysis of the strong gyrase site (SGS) of bacteriophage Mu: localization of determinants required for promoting Mu replication.

The Mu strong gyrase site (SGS), located in the centre of the Mu genome, is required for efficient Mu replication, as it promotes synapsis of the prophage termini. Other gyrase sites tested, even very strong ones, were unable to substitute for the SGS in Mu replication. To determine the features required for its unique properties, a deletion analysis was performed on the SGS. For this analysis, we defined the 20 bp centred on the midpoint of the 4 bp staggered cleavage made by gyrase to be the 'core' and the flanking sequences to be the 'arms'. The deletion analysis showed that (i) approximately 40 bp of the right arm is required, in addition to core sequences, for both efficient Mu replication and gyrase cleavage; and (ii) the left arm was not required for efficient Mu replication, although it was required for efficient gyrase cleavage. These observations implicated the right arm as the unique feature of the SGS. The second observation showed that strong gyrase cleavage and Mu replication could be dissociated and suggested that even weak gyrase sites, if supplied with the right arm of the SGS, could promote Mu replication. Hybrid sites were constructed with gyrase sites that could not support efficient Mu replication. The SGS right arm was used to replace one arm of the strong pSC101 gyrase site or the weaker pBR322 site. The pSC101 hybrid site allowed efficient Mu replication, whereas the pBR322 hybrid site allowed substantial, but reduced, replication. Hence, it appears that optimal Mu replication requires a central strong gyrase site with the properties imparted by the right arm sequences. Possible roles for the SGS right arm in Mu replication are addressed.

Bacteriophage mu↗
PubMed2000

Immunohistochemical expression of bcl-2 and p53 oncoproteins: correlation with Ki67 proliferation index and prognostic histopathologic parameters in colorectal neoplasia.

The bcl-2 oncogene plays an important role in carcinogenesis by inhibiting cell death (apoptosis). It was initially discovered in follicular B cell lymphoma with t(14,18) and subsequently found in other malignant and premalignant lesions. Alteration of the normal controls of cell proliferation is also a significant factor in the multistep process of tumorigenesis. The proliferative activity of a given lesion is commonly evaluated by MIB 1, a monoclonal antibody to Ki67 proliferation antigen. Mutation of the p53 gene is considered the most common genetic aberration in colorectal cancer. Immunohistochemical (IHC) staining expression of bcl-2, Ki67, and p53 was retrospectively investigated in a series of 52 colorectal carcinomas and 56 adenomas. The aim of the study was twofold: (i) to investigate any correlation between MIB 1, p53, and bcl-2 immunostaining expression in colonic adenomas and carcinomas and (ii) to identify any relation between these markers and several histopathologic parameters including tumor size, pathologic stage, lymph node metastasis, angiolymphatic invasion, tumor grade, and differentiation in colon carcinomas. bcl-2 was consistently higher in adenomas than in carcinomas. There were 44 of 56 (78.6%) adenomas and 27 of 52 (51.9%) carcinomas positive for bcl-2 (P = 0.004). The mean Ki67 labeling index (LI) was 30.05 +/- 7.6 and 38.12 +/- 11.01 in adenomas and carcinomas, respectively (P = 0.0001). p53 was significantly higher in carcinomas (35 of 52 [67.3%]) than in adenomas (18 of 56 [32.1%]) (P = 0.0004). Expression of bcl-2 in carcinoma was associated with a lower p53 levels and lower mean Ki67 LI and with favorable histopathologic parameters. Higher p53 and Ki67 values were associated with prognostically poor histopathologic features (differentiation and Duke's stage). We conclude that, in contrast to p53 and Ki67, bcl-2 oncoprotein expression is probably an early step in the process of colon carcinogenesis, and its expression may be associated with favorable pathologic parameters. Furthermore, an inverse relation exists between p53 and Ki67, and bcl-2 IHC expression in colonic neoplasia. Evaluation of bcl-2, p53, and Ki67 IHC expression in colonic carcinoma may be of value in predicting the clinical course in these patients.

Adenoma↗
PubMed2000

Bayesian inference for kappa from single and multiple studies.

Cohen's kappa coefficient is a widely popular measure for chance-corrected nominal scale agreement between two raters. This article describes Bayesian analysis for kappa that can be routinely implemented using Markov chain Monte Carlo (MCMC) methodology. We consider the case of m > or = 2 independent samples of measured agreement, where in each sample a given subject is rated by two rating protocols on a binary scale. A major focus here is on testing the homogeneity of the kappa coefficient across the different samples. The existing frequentist tests for this case assume exchangeability of rating protocols, whereas our proposed Bayesian test does not make any such assumption. Extensive simulation is carried out to compare the performances of the Bayesian and the frequentist tests. The developed methodology is illustrated using data from a clinical trial in ophthalmology.

Bayes Theorem↗
PubMed2000

Should the age specific prostate specific antigen cutoff for prostate biopsy be higher for black than for white men older than 50 years?

PURPOSE: Investigators who have examined age specific reference ranges recommend a higher prostate specific antigen (PSA) cutoff for biopsy for black than for white men older than 50 years. We controlled for PSA to determine whether age specific reference range cutoffs for diagnosis defined by the Walter Reed Army Medical Center group (Walter Reed group) would improve the disproportionate prostate cancer prognosis between black and white men. MATERIALS AND METHODS: We studied 651 consecutive patients who underwent radical prostatectomy at Wayne State University between 1991 and 1995 with a mean followup of 34 months (range 1.5 to 75). Log rank tests were used to determine the homogeneity of survival functions between black and white men with similar PSA ranges, and between groups defined by age specific PSA reference ranges for each race. RESULTS: Disease stage and grade were similar or worse in black men for any PSA range, and biochemical disease-free survival was similar or worse within each range. Black men had a higher percentage of high grade prostate cancer than white men 60 to 69 years old who would not have undergone biopsy using the Walter Reed group proposed PSA cutoff. CONCLUSIONS: Black men have similar or worse prostate cancer severity and outcome than white men with similar PSA ranges. Using age specific reference ranges for the PSA test defined by the Walter Reed group, black men have worse outcome than white men after radical prostatectomy. Therefore, we recommend that the PSA cutoff for biopsy should not be higher for black men at any age range.

Black or African American↗
PubMed2000

Prenatal diagnosis of beta-thalassaemia and other haemoglobinopathies in India.

This paper reports prenatal diagnosis of 787 fetuses of beta-thalassaemia and other haemoglobinopathies in Indian high-risk communities. DNA based diagnosis was offered in the first, as well as the second trimester, in 489 pregnancies (with five twins) on fetal tissues such as chorionic villus (CV) and amniocytes using the amplification refractory mutation system (ARMS) and restriction fragment length polymorphism (RFLP) techniques. Two hundred and ninety-two women (with one twin), who either presented late in the second trimester or whose DNA diagnosis was not informative, were offered prenatal diagnosis using globin chain synthesis (GCS) on fetal blood cells. Maternal contamination of fetal DNA was ruled out by variable number tandem repeat (VNTR) analysis using sites in four different genes (Apo-B, D1S-80, Ig-JH and Ha-ras), while contamination of fetal blood was checked by a particle size distribution channelyzer. Using both techniques we were able to offer complete diagnosis in 99.8% cases. Out of 494 fetuses tested by DNA analysis, 135 were found to be normal, 201 were carriers, whereas 146 were affected. Out of 293 fetuses analysed by GCS, 215 were unaffected and 71 were affected. In this study, both fetuses were tested in twin pregnancies, of which three required selective termination of one fetus. Because of social, religious taboos and family influences, genetic counselling was found to be an important guideline for couples selecting options for prenatal diagnosis. Our experience suggests that because of late presentation by many couples to the diagnostic centres, in developing countries like India, both the techniques of DNA analysis and GCS should be made available at major referral centres for maximum benefit to couples.

Amniocentesis↗
PubMed2000

Validity of mechanism of gene transfer in the process called conjugation in bacteria.

We have attempted a new evaluation of the process of conjugation in bacteria, because of some basic dissimilarities observed between this and that of eukaryotes, or plants and animals. Reference donor and recipient strains, widely used to prove conjugation in bacteria, were chosen; addition of DNase during the conjugation process, led to an unexpected but highly reproducible increase in the transconjugant colony counts (TCC; ca. > or = 1 log), when compared with that of the controls without DNase. Transconjugants were also obtained when the same live donors were substituted with the UV-killed ones although the TCC was very low initially. Contrarily, donors treated with DNA-intercalating agents, e.g. acridine orange or ethidium bromide, resulted in a complete failure to produce transconjugants. There was a quantitative relationship between the DNase used on donors and levels of DNA sugars/nucleotides/DNA, which possibly resulted from interaction between the DNase and DNA being present/produced on the donor surface. This may be indicative of what may actually happen in the donor-recipient mixtures in the conjugation test proper, where the recipient DNase may activate a donor DNA production cycle. The evidences presented did not suggest that the donor DNA in the conjugation process is actually vestibuled through any intercellular conjugation passages, and is susceptible to the action of DNase or the intercalating dyes.

Animals↗
PubMed1999

Prevalence of the inactivating 609C-->T polymorphism in the NAD(P)H:quinone oxidoreductase (NQO1) gene in patients with primary and therapy-related myeloid leukemia.

NAD(P)H:quinone oxidoreductase (NQO1) converts benzene-derived quinones to less toxic hydroquinones and has been implicated in benzene-associated hematotoxicity. A point mutation in codon 187 (Pro to Ser) results in complete loss of enzyme activity in homozygous subjects, whereas those with 2 wild-type alleles have normal activity. The frequency of homozygosity for the mutant allele among Caucasians and African Americans is 4% to 5% but is higher in Hispanics and Asians. Using an unambiguous polymerase chain reaction (PCR) method, we assayed nonmalignant lymphoblastoid cell lines derived from 104 patients with myeloid leukemias; 56 had therapy-related acute myeloid leukemia (t-AML), 30 had a primary myelodysplastic syndrome (MDS), 9 had AML de novo, and 9 had chronic myelogenous leukemia (CML). All patients had their leukemia cells karyotyped. Eleven percent of the t-AML patients were homozygous and 41% were heterozygous for the NQO1 polymorphism; these proportions were significantly higher than those expected in a population of the same ethnic mix (P =.036). Of the 45 leukemia patients who had clonal abnormalities of chromosomes 5 and/or 7, 7 (16%) were homozygous for the inactivating polymorphism, 17 (38%) were heterozygous, and 21 (47%) had 2 wild-type alleles for NQO1. Thus, NQO1 mutations were significantly increased compared with the expected proportions: 5%, 34%, and 61%, respectively (P =.002). An abnormal chromosome no. 5 or 7 was observed in 7 of 8 (88%) homozygotes, 17 of 45 (38%) heterozygotes, and 21 of 51 (41%) patients with 2 wild-type alleles. Among 33 patients with balanced translocations [14 involving bands 11q23 or 21q22, 10 with inv(16) or t(15;17), and 9 with t(9;22)], there were no homozygotes, 15 (45%) heterozygotes, and 18 (55%) with 2 wild-type alleles. Whereas fewer than 3 homozygotes were expected among the 56 t-AML patients, 6 were observed; 19 heterozygotes were expected, but 23 were observed. The gene frequency for the inactivating polymorphism (0. 31) was increased approximately 1.4-fold among the 56 t-AML patients. This increase was observed within each of the following overlapping cohorts of t-AML patients: the 43 who had received an alkylating agent, the 27 who had received a topoisomerase II inhibitor, and the 37 who had received any radiotherapy. Thus, the frequency of an inactivating polymorphism in NQO1 appears to be increased in this cohort of myeloid leukemias, especially among those with t-AML or an abnormality of chromosomes 5 and/or 7. Homozygotes and heterozygotes (who are at risk for treatment-induced mutation or loss of the remaining wild-type allele in their hematopoietic stem cells) may be particularly vulnerable to leukemogenic changes induced by carcinogens.

Alleles↗