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M Banerjee

Publications and source records attributed to M Banerjee.

At least 37 records · Page 2Linked to original sources
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

The Sgs1 helicase of Saccharomyces cerevisiae inhibits retrotransposition of Ty1 multimeric arrays.

Ty1 retrotransposons in the yeast Saccharomyces cerevisiae are maintained in a genetically competent but transpositionally dormant state. When located in the ribosomal DNA (rDNA) locus, Ty1 elements are transcriptionally silenced by the specialized heterochromatin that inhibits rDNA repeat recombination. In addition, transposition of all Ty1 elements is repressed at multiple posttranscriptional levels. Here, we demonstrate that Sgs1, a RecQ helicase required for genome stability, inhibits the mobility of Ty1 elements by a posttranslational mechanism. Using an assay for the mobility of Ty1 cDNA via integration or homologous recombination, we found that the mobility of both euchromatic and rDNA-Ty1 elements was increased 32- to 79-fold in sgs1Delta mutants. Increased Ty1 mobility was not due to derepression of silent rDNA-Ty1 elements, since deletion of SGS1 reduced the mitotic stability of rDNA-Ty1 elements but did not stimulate their transcription. Furthermore, deletion of SGS1 did not significantly increase the levels of total Ty1 RNA, protein, or cDNA and did not alter the level or specificity of Ty1 integration. Instead, Ty1 cDNA molecules recombined at a high frequency in sgs1Delta mutants, resulting in transposition of heterogeneous Ty1 multimers. Formation of Ty1 multimers required the homologous recombination protein Rad52 but did not involve recombination between Ty1 cDNA and genomic Ty1 elements. Therefore, Ty1 multimers that transpose at a high frequency in sgs1Delta mutants are formed by intermolecular recombination between extrachromosomal Ty1 cDNA molecules before or during integration. Our data provide the first evidence that the host cell promotes retrotransposition of monomeric Ty1 elements by repressing cDNA recombination.

DNA Helicases↗
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↗
PubMed2001

Birds disperse ixodid (Acari: Ixodidae) and Borrelia burgdorferi-infected ticks in Canada.

A total of 152 ixodid ticks (Acari: Ixodidae) consisting of nine species was collected from 82 passerine birds (33 species) in 14 locations in Canada from 1996 to 2000. The Lyme disease spirochete Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwaldt & Brenner was cultured from the nymph of a blacklegged tick, Ixodes scapularis Say, that had been removed from a common yellowthroat, Geothlypis trichas L., from Bon Portage Island, Nova Scotia. As a result of bird movement, a nymphal I. scapularis removed from a Swainson's thrush, Catharus ustulatus incanus (Godfrey), at Slave Lake, Alberta, during spring migration becomes the new, most western and northern record of this tick species in Canada. Amblyomma longirostre Koch, Amblyomma sabanerae Stoll, and Ixodes baergi Cooley & Kohls are reported for the first time in Canada. Similarly, Amblyomma americanum L., Arnblyomma maculatum Koch, and ixodes muris Bishopp & Smith are reported for the first time on birds in Canada. After removal of an I. muris gravid female from a song sparrow, Melospiza melodia Wilson, at St. Andrews, New Brunswick, eggs were laid, which developed into larvae, and this new tick-host record demonstrates that birds have the potential to start a new tick population. We conclude that passerine birds disperse several species of ixodid ticks in Canada, and during spring migration translocate ticks from the United States, and Central and South America, some of which are infected with B. burgdorferi.

Animals↗
PubMed2001

Phase II randomized clinical trial of lycopene supplementation before radical prostatectomy.

An inverse association has been observed between dietary intake of lycopene and the risk of prostate cancer. We investigated the effects of lycopene supplementation in patients with prostate cancer. Twenty-six men with newly diagnosed, clinically localized (14 T(1) and 12 T(2)) prostate cancer were randomly assigned to receive 15 mg of lycopene (n = 15) twice daily or no supplementation (n = 11) for 3 weeks before radical prostatectomy. Biomarkers of differentiation and apoptosis were assessed by Western blot analysis on benign and malignant parts of the prostate gland. Prostatectomy specimens were entirely embedded, step-sectioned, and evaluated for pathological stage, Gleason score, volume of cancer, and extent of high-grade prostatic intraepithelial neoplasia. Plasma levels of lycopene, insulin-like growth factor-1 (IGF-1), IGF binding protein-3, and prostate-specific antigen were measured at baseline and after 3 weeks of supplementation or observation. Eleven (73%) subjects in the intervention group and two (18%) subjects in the control group had no involvement of surgical margins and/or extra-prostatic tissues with cancer (P = 0.02). Twelve (84%) subjects in the lycopene group and five (45%) subjects in the control group had tumors <4 ml in size (P = 0.22). Diffuse involvement of the prostate by high-grade prostatic intraepithelial neoplasia was present in 10 (67%) subjects in the intervention group and in 11 (100%) subjects in the control group (P = 0.05). Plasma prostate-specific antigen levels decreased by 18% in the intervention group, whereas they increased by 14% in the control group (P = 0.25). Expression of connexin 43 in cancerous prostate tissue was 0.63 +/- 0.19 absorbance in the lycopene group compared with 0.25 +/- 0.08 in the control group (P = 0.13). Expression of bcl-2 and bax did not differ significantly between the two study groups. IGF-1 levels decreased in both groups (P = 0.0002 and P = 0.0003, respectively). The results suggest that lycopene supplementation may decrease the growth of prostate cancer. However, no firm conclusions can be drawn at this time because of the small sample size.

Administration, Oral↗
PubMed2001

Acute disseminated encephalomyelitis--another cause of post malaria cerebellar ataxia.

The aetio-pathogenesis of delayed onset cerebellar ataxia following Plasmodium falciparum malaria is uncertain. An autoimmune demyelinating pathology has been suspected though not yet definitively substantiated. In the present communication we report a case of delayed onset cerebellar ataxia following acute falciparum malaria, where magnetic resonance imaging revealed demyelinating lesions in the pons and cerebellar peduncles which disappeared after resolution of symptoms.

Acute Disease↗
PubMed2001

JU-2, a novel phosphorous-containing antifungal antibiotic from Streptomyces kanamyceticus M8.

A novel phosphorous-containing antifungal antibiotic JU-2 was isolated from Streptomyces kanamyceticus M8. Quantitative chemical analysis shows the presence of two phenylalanines, two glucose, one linoleic acid, one crucic acid and one phosphonamide moiety per molcule of the antibiotic. JU-2 shows strong inhibitory activity against various pathogenic and non-pathogenic fungi but no activity against bacteria and yeast.

Aminoglycosides↗
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↗