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.

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.

Correlation of bcl-2 oncoprotein immunohistochemical expression with proliferation index and histopathologic parameters in colorectal neoplasia

Thebcl-2oncogene 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 valuated by MIB1, a monoclonal antibody to Ki67 proliferation antigen. Immuno-histochemical (IHC) staining expression of bcl-2 and Ki67 was retrospectively investigated in a series of 52 colorectal carcinomas and 56 adenomas according to the avidin-biotin-complex method. The aim of the study was twofold: 1) to investigate any correlation between MIB1 and bcl-2 immunostaining expression in colonic adenomas and carcinomas, 2) to identify any relationship between either marker and several histopathologic parameters including tumor size, pathologic stage, lymph node metastasis, angio-lymphatic invasion, tumor grade and differentiation in colon carcinomas. Bcl-2 was consistently higher in adenomas than in carcinomas. There were 44/56 (78.6%) adenomas, and 27/52 (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). Expression of bcl-2 in carcinoma was significantly associated with a lower mean Ki67 LI and with favorable histopathologic parameters. We conclude that bcl-2 oncoprotein expression is probably an early step in the process of colon carcinogenesis, and its expression may be associated with a favorable clinical course. Furthermore, an inverse relationship exists between bcl-2 and Ki67 in colonic neoplasia. Evaluation of bcl-2 and Ki67 IHC expression in colonic carcinoma should be performed prospectively to determine if their expression is of value in predicting the clinical course in these patients.

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.

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.

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.

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

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.

Replacement of the bacteriophage Mu strong gyrase site and effect on Mu DNA replication

The bacteriophage Mu strong gyrase site (SGS) is required for efficient replicative transposition and functions by promoting the synapsis of prophage termini. To look for other sites which could substitute for the SGS in promoting Mu replication, we have replaced the SGS in the middle of the Mu genome with fragments of DNA from various sources. A central fragment from the transposing virus D108 allowed efficient Mu replication and was shown to contain a strong gyrase site. However, neither the strong gyrase site from the plasmid pSC101 nor the major gyrase site from pBR322 could promote efficient Mu replication, even though the pSC101 site is a stronger gyrase site than the Mu SGS as assayed by cleavage in the presence of gyrase and the quinolone enoxacin. To look for SGS-like sites in the Escherichia coli chromosome which might be involved in organizing nucleoid structure, fragments of E. coli chromosomal DNA were substituted for the SGS: first, repeat sequences associated with gyrase binding (bacterial interspersed mosaic elements), and, second, random fragments of the entire chromosome. No fragments were found that could replace the SGS in promoting efficient Mu replication. These results demonstrate that the gyrase sites from the transposing phages possess unusual properties and emphasize the need to determine the basis of these properties.

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.

Role of radical prostatectomy in patients with prostate cancer of high Gleason score

BACKGROUND

The routine use of serum prostate-specific antigen (PSA) testing combined with digital rectal examination has lowered tumor volume and clinical-pathological stage of men undergoing radical prostatectomy. Therefore, we may identify more men with poorly differentiated tumors of early clinical stage. In order to identify those who may benefit from radical prostatectomy, we evaluated known prognostic variables in patients with prostate cancer of high Gleason score (8-10).

METHODS

Of 652 patients who underwent a radical prostatectomy as monotherapy for clinically localized prostate cancer between March 1991-December 1995, 84 patients with prostatectomy specimen Gleason score 8-10 tumors were identified. Clinical-pathological data were obtained from our prostate cancer database. Gleason score, PSA level, margin status, pathologic stage, and tumor volume were analyzed as general prognostic variables for disease-free survival (DFS). Follow-up ranged from 13-84 months (median, 36.2). Biochemical recurrence was defined as a postoperative PSA elevation greater than 0.4 ng/ml.

RESULTS

The DFS for patients with Gleason score 8-10 and pathologically organ-confined disease was 62.5%. DFS was 56.2% for patients with PSA < or =10 ng/ml, compared to 19.2% for patients with serum PSA >10 ng/ml (P = 0.009). Patients with nonspecimen-confined disease (positive margins) had a DFS rate of 26.6% vs. 55% for patients with specimen-confined disease (negative margins) (P = 0.009). On multivariable analysis, only preoperative PSA < or =10 ng/ml (P = 0.02) and surgical margin status (P = 0.04) were significant predictors of DFS.

CONCLUSIONS

Surgical margin status and preoperative serum PSA level are independent predictors of DFS for patients with high Gleason score prostate cancer treated by radical prostatectomy as monotherapy. Patients with poorly differentiated prostate cancer treated surgically at an early stage can have a favorable prognosis, especially if negative surgical margins are obtained. A preoperative serum PSA level < or =10 ng/ml carries the greatest likelihood of achieving prolonged DFS in this group of patients.

Evolution of the high molecular weight glutenin loci of the A, B, D, and G genomes of wheat

We used PCR to obtain phylogenetically informative sequences from the high molecular weight glutenin genes of wheat. The validity of partial sequence comparisons as a means of studying glutenin phylogenetics was established by constructing neighbour-joining trees from partial alignments of 12 published glutenin allele sequences. PCR was then used to obtain 20 novel glutenin allele sequences from various Triticum and Aegilops species, including a 3000 year old preserved wheat. A neighbour-joining tree derived from all known glutenin allele sequences had eight clades, representing the eight loci from which the allele sequences were derived, and was split into two halves, one comprising alleles from the Glu-1-1 loci and the other comprising Glu-1-2 alleles. The topology was compatible with the postulated relationships between the A, B, D, and G genomes. The Glu gene duplication event was tentatively dated at 7.2-10.0 million years ago (MYA), the origin of the four genomes at 5.0-6.9 MYA, and the split between the B and G genomes at 2.5-3.5 MYA. The Glu-B1-1 alleles in cultivated wheats fell into two subgroups that diverged 1.4-2.0 MYA, suggesting that emmer was domesticated twice. The D allele sequences were relatively diverse, indicating that the hybridization event that resulted in the hexaploid bread wheats might have occurred more than once.

Outcome of palliative urinary diversion in the treatment of advanced malignancies

BACKGROUND

It is unclear whether palliative endourologic or percutaneous urinary diversion in the treatment of advanced cancer provides significant improvement in quality or duration of life. The purpose of this study was to evaluate survival and performance status after endourologic palliative urinary diversion in patients with advanced malignancy and to compare the results for different malignancies.

METHODS

One hundred three patients with advanced malignancies underwent palliative urinary diversion (stent or nephrostomy) between 1986 and 1997. Ninety-two patients and 11 patients had bilateral and unilateral obstruction, respectively. Indications, complications, performance status after diversion, and survival for patients with different malignancies were identified and compared. A modified Karnofsky performance scale (KPS) was used for assessment of physical performance. A scale of 0-4 was used: 0) hospitalized until death; 1) bedridden at home, severe pain despite analgesia; 2) moderate disability, moderate pain despite analgesia; 3) mild disability, pain free with medication; and 4) normal.

RESULTS

The mean age of patients was 68 years. The mean pre- and postoperative creatinine levels were 6 mg/dL and 3.3 mg/dL, respectively (P < 0.0001). The median survival and days of hospitalization were 112 and 45, respectively. The median postdiversion KPS score was 2 (range, 0-4), and 15% of patients never left the hospital. Overall, 51% required secondary percutaneous procedures, and 68.4% had complications (minor, 63%; major, 5.4%).

CONCLUSIONS

Most patients with advanced cancers had poor performance status and survival after diversion. Eighty six percent had cancer-related symptoms despite the diversion. The average survival was 5 months, 50% of which was spent in the hospital. Primary endourologic procedures had a high failure rate, and additional procedures were required.

Outcome of palliative urinary diversion in the treatment of advanced malignancies

BACKGROUND

It is unclear whether palliative endourologic or percutaneous urinary diversion in the treatment of advanced cancer provides significant improvement in quality or duration of life. The purpose of this study was to evaluate survival and performance status after endourologic palliative urinary diversion in patients with advanced malignancy and to compare the results for different malignancies.

METHODS

One hundred three patients with advanced malignancies underwent palliative urinary diversion (stent or nephrostomy) between 1986 and 1997. Ninety-two patients and 11 patients had bilateral and unilateral obstruction, respectively. Indications, complications, performance status after diversion, and survival for patients with different malignancies were identified and compared. A modified Karnofsky performance scale (KPS) was used for assessment of physical performance. A scale of 0-4 was used: 0) hospitalized until death; 1) bedridden at home, severe pain despite analgesia; 2) moderate disability, moderate pain despite analgesia; 3) mild disability, pain free with medication; and 4) normal.

RESULTS

The mean age of patients was 68 years. The mean pre- and postoperative creatinine levels were 6 mg/dL and 3.3 mg/dL, respectively (P < 0.0001). The median survival and days of hospitalization were 112 and 45, respectively. The median postdiversion KPS score was 2 (range, 0-4), and 15% of patients never left the hospital. Overall, 51% required secondary percutaneous procedures, and 68.4% had complications (minor, 63%; major, 5.4%).

CONCLUSIONS

Most patients with advanced cancers had poor performance status and survival after diversion. Eighty six percent had cancer-related symptoms despite the diversion. The average survival was 5 months, 50% of which was spent in the hospital. Primary endourologic procedures had a high failure rate, and additional procedures were required.

Lymph node size does not correlate with the presence of prostate cancer metastasis

OBJECTIVES

To determine whether lymph node size is a surrogate marker for lymph node metastasis.

METHODS

We reviewed 980 patients who underwent radical retropubic prostatectomy with bilateral pelvic lymph node dissection for clinically localized prostate cancer, of whom 63 had lymph node metastases. A comparable group of patients with prostate cancer undergoing radical prostatectomy who did not have lymph node involvement was identified using the following parameters: serum prostate-specific antigen level, clinical and pathologic stage, and pre- and postoperative Gleason score. The axial and longitudinal dimensions of the nodes from patients with and without metastases were analyzed to assess the significance of lymph node size in predicting the presence of metastases. All patients had negative preoperative computed tomography (CT) and bone scans. Of the 63 patients with lymph node metastases, 48 had tissue available for measuring the dimensions of the lymph nodes.

RESULTS

A total of 76 metastatic and 92 negative lymph nodes were identified from the patients with and without metastatic nodes, respectively. The mean nodal longitudinal size was 1.65 cm (range 0.2 to 6.5) and 3.50 cm (range 0.5 to 9) for positive and negative nodes, respectively (P = 0.0001). The mean axial nodal size was 0.8 cm (range 0.2 to 3.2) and 1.0 cm (range 0.2 to 2.2) for positive and negative lymph nodes, respectively. In 56 metastatic nodes (74%), the axial size was less than 1 cm and in 20 (26%) less than 5 mm.

CONCLUSIONS

Lymph node size should not be used as a surrogate for the presence of lymph node metastases. Although no patient had enlarged lymph nodes by CT scan criteria (greater than 1.5 cm), 6 (8%) of 48 and 19 (12%) of 48 patients with and without lymph node metastases, respectively, had nodes with an axial dimension greater than 1.5 cm.

Should Gleason score 7 prostate cancer be considered a unique grade category?

OBJECTIVES

To evaluate pathologic characteristics and biochemical survival rate differences between patients with Gleason score 6 or less, 7, and 8 or more prostate cancer.

METHODS

A total of 652 patients who underwent a radical prostatectomy for clinically localized prostate cancer between March 1991 and December 1995 were selected for this study. Patients who underwent neoadjuvant or adjuvant hormonal therapy or radiotherapy were excluded. Clinical and pathologic data were obtained from our prostate cancer data base. Serum prostate-specific antigen (PSA) level, pathologic stage, and disease-free survival (DFS) were analyzed between the three Gleason score groups.

RESULTS

The overall mean pretreatment serum PSA level was 12.9 ng/mL, being 8.4, 13.4, and 23 ng/mL for Gleason score 6 or less, 7, and 8 or more prostate cancers, respectively (P = 0.0001). Of patients with specimen Gleason score 6 or less, 7, and 8 or more, pathologic organ-confined disease was present in 69.4%, 43.1 %, and 9.2%, respectively (P = 0.001). Extraprostatic extension was present in 30.6%, 56.9%, and 90.8% (P = 0.0001); positive surgical margins, considered independently from the other pathologic findings, were present in 31 %, 47.6%, and 67.8% of patients with Gleason score 6 or less, 7, and 8 or more, respectively (P = 0.0001). DFS was 34.5% for patients with Gleason score 8 or more, 75% for Gleason score 7, and 91.2% for Gleason score 6 or less prostate cancers, at a median follow-up of 34.2 months (P = 0.0001). On multivariable analysis, after adjusting for serum PSA level (10 or less or more than 10 ng/mL) and pathologic stage, Gleason score (6 or less, 7, 8 or more) remained a statistically significant predictor of DFS (P = 0.0001).

CONCLUSIONS

Patients with Gleason score 7 prostate cancer should be considered a specific prognostic category. We believe that this distinction is critical to obtain more reliable results from prostate cancer analyses about prognosis of patients treated with curative intent.

Should African-American men be tested for prostate carcinoma at an earlier age than white men?

BACKGROUND

There have recently been challenges to testing high risk populations, i.e., African-American men younger than 50 years, for prostate carcinoma (PCa). The mortality rate of patients with PCa between ages 40 and 60 years is nearly 3 times greater among African-American men (AAM) compared with white men (WM). The literature in support of testing AAM at an earlier age than WM is sparse. Therefore, the authors present clinical and histologic data that support the testing of AAM at a younger age, utilizing data on patients with clinically localized PCa.

METHODS

Examination of consecutive radical prostatectomy specimens from AAM and WM was performed from January 1991 to June 1996 among AAM and WM at Wayne State University, Harper Hospital, Detroit, Michigan. International, salvage prostatectomy, and neoadjuvant hormonal therapy patients were excluded, as were patients with lymph node metastasis. The authors examined biochemical recurrences of PCa in this cohort of men treated from January 1991 through December 1995. Univariate analysis of contingency tables was performed, using chi-squared-tests to assess the correlation between stage and race after stratification of patients by age group. Biochemical recurrence was analyzed using the Kaplan-Meier method and the log rank test.

RESULTS

The authors examined radical prostatectomy specimens from 759 patients and biochemical recurrence outcome of 655 patients. AAM patients ages 50-69 years had higher prostate specific antigen levels, worse Gleason scores, more advanced stages of disease, and a higher recurrence rate. However, among men ages 70-79 years, there was no difference in these parameters between AAM and WM. Among men ages 40-49 years, a larger sample size is necessary to make meaningful comparisons.

CONCLUSIONS

Data on the outcomes of men treated for clinically localized PCa demonstrated more advanced disease and more frequent recurrence among young AAM than among WM, young and of advanced age. These differences in disease severity and recurrence, in addition to the disproportionate mortality among young AAM, are strong evidence that AAM should be tested for PCa at an earlier age than WM.

Tumor angiogenesis in vulvar squamous cell carcinoma

OBJECTIVE

Angiogenesis has been shown to correlate positively with the presence of metastatic disease in some tumors, but has not been studied in invasive vulvar squamous cell carcinoma. Fifty cases of invasive vulvar squamous cell carcinoma were studied in an effort to correlate angiogenesis with stage, survival, and pattern of invasion.

METHODS

These patients were diagnosed between 1987 and 1993. Microvessels were identified immunohistochemically using antibody to Factor VIII, and areas of greatest microvessel density associated with tumor were counted. The pattern of invasion was categorized as "spray," "pushing," or "mixed." The mean microvessel count was correlated with surgical and clinical stage, pattern of invasion, and survival.

RESULTS

Mean microvessel counts in surgical stage I/II cases (31.1 +/- 7.3) were not significantly different from stage III/IV cases (26.3 +/- 8.6) (P = 0.089). Similarly mean microvessel counts in clinical stage I/II cases (31.6 +/- 11.9) were not significantly different from stage III/IV cases (27.0 +/- 8.7) (P = 0.198). Seventeen patients who died of disease had mean counts of 26.1 +/- 6.4, while 21 patients alive with or without evidence of disease had counts of 31.1 +/- 10.8 (P = 0.087). Mean microvessel counts did not vary significantly with the spray pattern (30.1 +/- 8. 7), pushing pattern (31.4 +/- 12.9), or mixed pattern of invasion (31.4 +/- 12.9) (P = 0.920).

CONCLUSIONS

Tumor angiogenesis in vulvar squamous cell carcinoma does not correlate positively with stage, survival, or pattern of invasion and cannot be used as a prognostic indicator.

Development of a highly sensitive direct microtiter plate ELISA for human serum testosterone

A simple, highly sensitive, direct, competitive ELISA for human serum testosterone has been indigenously developed. Specific antisera against testosterone were raised in rabbits using testosterone-3carboxymethyl oxime (CMO)-bovine serum albumin (BSA) as the antigen. For the enzyme conjugate, testoterone-3CMO was coupled with horse raddish peroxidase by the active ester method. The standard curve covered a wide range from 3.9 pg/ml to 500 pg/ml. The inter and intra-assay variation were found to be low and within the acceptable limits. Specificity and accuracy for the assay was established by having negligible crossreactivity with the related steroids and an excellent parallelism between the sample and standard dilution curve. Samples measured by RIA and ELISA showed very high degree of correlation (r=0.991).

Population-based study of pelvic lymph node positivity in clinically localized prostate cancer: a study comparing African Americans and whites

OBJECTIVES

To evaluate the correlation between race and lymph node metastasis for prostate cancer by analyzing which preoperative parameters may predict lymph node status in both races.

METHODS

We analyzed a group of patients (552 American white men [AWM] and 423 African-American men [AAM]) who underwent radical prostatectomy plus modified pelvic lymphadenectomy between January 1991 and June 1997. Patients who received neoadjuvant radiation or hormone therapy were excluded. Univariate and multivariate analyses were performed to determine the influence of race on lymph node positivity, as well as to correlate the preoperative parameters (serum prostate-specific antigen [PSA], biopsy Gleason score, and clinical stage) with lymph node metastasis for each race separately.

RESULTS

The AAM presented with significantly higher preoperative Gleason scores and PSA levels than AWM. However, comparing lymph node status by race, the difference of positivity (41 AWM [7.4% and 22 AAM [5.2%]) was not statistically significant (P = 0.16). The percentage of positive nodes was similar in both races for each subset of PSA, Gleason score, and clinical stage. Despite the statistical significance of the three preoperative parameters in univariate analysis, in multivariate analysis only PSA and Gleason score were independent predictors of positive lymph nodes.

CONCLUSIONS

There is no influence of race on lymph node metastasis, despite AAM presenting with higher preoperative Gleason scores and PSA levels. In multivariate analysis, preoperative Gleason score and PSA were independent factors for positive nodes regardless of race.

Tick-borne relapsing fever in British Columbia, Canada: first isolation of Borrelia hermsii

The spirochete that causes tick-borne relapsing fever, Borrelia hermsii, was isolated in pure culture during 1995 and 1996 from three acutely ill human patients infected in southern British Columbia, Canada. The geographic area of exposure is a known focus of this disease dating back to 1930 when the first case was recognized in a human. Analyses of plasmid DNA, protein profiles, and reactivity with a species-specific monoclonal antibody identified the new isolates of spirochetes as B. hermsii, all of which were most similar to an isolate of this spirochete from northern California described previously. These are the first reported isolates of B. hermsii from Canada.

Racial differences and prognostic significance of tumor location in radical prostatectomy specimens

BACKGROUND

Our objective was to evaluate radical prostatectomy specimens for possible racial differences in tumor location, as well as to correlate tumor location with pathologic stage and disease-free survival.

METHODS

Between January 1991-December 1997, 1,245 patients underwent radical prostatectomy with bilateral pelvic lymphadenectomy for clinically localized prostate cancer. Seven hundred and eighty-five patients who were treated with surgery as monotherapy were evaluated. Tumor location, defined as mainly anterior, mainly posterior, or both (anterior and posterior), was obtained from review of tumor maps prepared from pathological evaluation of completely embedded, resected specimens.

RESULTS

Overall tumor location was anterior in 107 (14%), posterior in 459 (58%), and both in 219 (28%) cases. The incidence of anterior tumors was higher in African American men compared to Caucasians (16% vs. 11%, P = 0.045). The rate of positive surgical margins in anteriorly and posteriorly located tumors was 60% vs. 38% in African American men (P = 0.001) and 48% vs. 27% in Caucasians (P = 0.001), respectively. African American men were found to have a higher incidence of positive surgical margins (50%; 174/348) compared to Caucasian men (34%; 150/437; P = 0.001).

CONCLUSIONS

Anterior tumors were present in 14% of our patients. African American men have a greater percentage of anterior tumors than do Caucasians. In addition, a higher rate of positive surgical margins was encountered in patients with anterior tumors, especially if they were African American men. In patients with an abnormal serum prostate-specific antigen level and negative sextant prostate biopsies, we recommend biopsy of the anterior zone of the prostate.

Limited role of radionuclide bone scintigraphy in patients with prostate specific antigen elevations after radical prostatectomy

PURPOSE

Bone scintigrams of patients with increasing serum prostate specific antigen (PSA) after radical prostatectomy are only rarely positive. We identify clinical parameters that would improve our ability to select patients for this imaging study.

MATERIALS AND METHODS

We reviewed all bone scintigrams done at our institution between 1991 and 1996 in patients with persistently increasing serum PSA after radical prostatectomy. What prompted the clinician to obtain the bone scintigram was trigger PSA (tPSA). The rate of increase in PSA to tPSA was measured by tPSA/time from radical prostatectomy (slope 1) and tPSA/time from last undetectable PSA (slope 2). These parameters were evaluated together with standard clinicopathological data in univariate and multivariate analyses to determine the ability to predict the bone scintigram result.

RESULTS

In univariate analysis tPSA (p = 0.003), slope 1 (p = 0.005) and slope 2 (p = 0.004) were useful in predicting the bone scintigram result but pathological stage, Gleason score, preoperative PSA and time to recurrence were not. In multivariate analysis the single most useful parameter in predicting the bone scintigram result was tPSA (p = 0.01). Based on a logistic regression model the probability of a positive bone scintigram was less than 5% until tPSA increased to 40 to 45 ng./ml.

CONCLUSIONS

In patients with increasing serum PSA after radical prostatectomy current serum PSA is the best predictor of the bone scintigram result. Furthermore, there is limited usefulness of bone scintigraphy until PSA increases above 30 to 40 ng./ml.

Effect of neoadjuvant androgen deprivation on circulating prostate cells in the bone marrow of men undergoing radical prostatectomy

Our objective was to determine the effect of neoadjuvant hormonal therapy on the presence of circulating prostate cells in patients undergoing radical prostatectomy for prostate cancer. A total of 60 patients at high risk for extraprostatic disease were analyzed for the presence of circulating prostate cells using reverse transcriptase PCR (RTPCR) amplification of the prostate-specific antigen mRNA. Twenty-nine patients underwent radical prostatectomy for a clinical T2b-c tumor or a stage T1c-T2a tumor and a serum prostate-specific antigen level > or =10ng/ml (radical prostatectomy alone), and 31 similarly staged patients received neoadjuvant hormonal therapy before radical prostatectomy (neoadjuvant). Bone marrow samples were used for RTPCR analysis. Twenty-four percent and 58% of the radical-prostatectomy-alone patients and neoadjuvant patients had organ-confined disease, respectively (P = 0.007). In the radical-prostatectomy-alone group, 77% and 14% of patients with extraprostatic and organ-confined disease were RTPCR positive, respectively (P = 0.03). However, in the neoadjuvant group, 46% and 28% of patients with extraprostatic and organ-confined disease were RTPCR positive, respectively (P = 0.29). For patients that were RTPCR positive, 45 % of the neoadjuvant patients had organ-confined disease compared with 6% in the radical-prostatectomy-alone patients (P = 0.018). These data suggest that a subset of the neoadjuvant patients are converted to organ confined disease without eliminating the prostate cells in the bone marrow. Our data suggest that hormonal therapy before radical prostatectomy decreases the occurrence of extraprostatic disease but, to a lesser degree, the incidence of circulating prostate cells. This may partially explain why hormonal therapy before radical prostatectomy has not improved disease-free survival.

Prognostic indicators in patients with seminal vesicle involvement following radical prostatectomy for clinically localized prostate cancer

PURPOSE

We identify prognostic factors in patients with seminal vesicle involvement and negative lymph nodes following radical prostatectomy for clinically localized prostate cancer.

MATERIALS AND METHODS

A total of 93 patients who underwent radical prostatectomy and had seminal vesicle invasion without lymph node metastasis were evaluated. Patients who underwent neoadjuvant/adjuvant hormonal or radiation therapy were excluded from study. Preoperative serum prostate specific antigen (PSA), biopsy and radical prostatectomy specimen Gleason score, surgical margin status, presence of extraprostatic extension and evidence of biochemical disease progression were determined prospectively. Biochemical failure was defined as a single serum PSA elevation greater than 0.4 ng./ml.

RESULTS

The presence of positive surgical margins (p = 0.001), and Gleason score 7 or higher from preoperative biopsies (p = 0.03) and from the radical prostatectomy specimen (p = 0.01) were significant predictors of disease progression at a median followup of 43.3 months. Patients with preoperative PSA less than 10 ng./ml. had a better disease-free survival (p = 0.07). On multivariate analysis, after adjusting for biopsy Gleason score, prostatectomy Gleason score and serum PSA, positive surgical margins remained a statistically significant predictor of disease progression (p = 0.002).

CONCLUSIONS

Surgical margin status is an independent predictor of disease recurrence in patients with seminal vesicle involvement and negative lymph nodes following radical prostatectomy. Serum PSA 10 ng./ml. or greater and specimen Gleason score 7 or greater also were adverse prognostic factors in these patients. Conversely, patients with negative surgical margins and lymph nodes have a better prognosis than previously expected, despite seminal vesicle invasion.

Prognostic indicators in patients with seminal vesicle involvement following radical prostatectomy for clinically localized prostate cancer

PURPOSE

We identify prognostic factors in patients with seminal vesicle involvement and negative lymph nodes following radical prostatectomy for clinically localized prostate cancer.

MATERIALS AND METHODS

A total of 93 patients who underwent radical prostatectomy and had seminal vesicle invasion without lymph node metastasis were evaluated. Patients who underwent neoadjuvant/adjuvant hormonal or radiation therapy were excluded from study. Preoperative serum prostate specific antigen (PSA), biopsy and radical prostatectomy specimen Gleason score, surgical margin status, presence of extraprostatic extension and evidence of biochemical disease progression were determined prospectively. Biochemical failure was defined as a single serum PSA elevation greater than 0.4 ng./ml.

RESULTS

The presence of positive surgical margins (p = 0.001), and Gleason score 7 or higher from preoperative biopsies (p = 0.03) and from the radical prostatectomy specimen (p = 0.01) were significant predictors of disease progression at a median followup of 43.3 months. Patients with preoperative PSA less than 10 ng./ml. had a better disease-free survival (p = 0.07). On multivariate analysis, after adjusting for biopsy Gleason score, prostatectomy Gleason score and serum PSA, positive surgical margins remained a statistically significant predictor of disease progression (p = 0.002).

CONCLUSIONS

Surgical margin status is an independent predictor of disease recurrence in patients with seminal vesicle involvement and negative lymph nodes following radical prostatectomy. Serum PSA 10 ng./ml. or greater and specimen Gleason score 7 or greater also were adverse prognostic factors in these patients. Conversely, patients with negative surgical margins and lymph nodes have a better prognosis than previously expected, despite seminal vesicle invasion.

Salvage surgery or salvage radiotherapy for locally recurrent prostate cancer

OBJECTIVES

To evaluate the efficacy and toxicity of salvage radiation or surgery for locally recurrent tumor after initial treatment for clinically localized prostate cancer.

METHODS

The treatment records of 70 patients with local treatment failure after definitive therapy for clinically localized prostate cancer were reviewed. Initial treatment consisted of external beam radiation therapy (RT) in 27 patients and radical retropubic prostatectomy (RP) in 43 patients.

RESULTS

The mean serum PSA levels were similar in both groups before initial treatment: 8.5 and 10.5 ng/mL for the salvage RP and salvage RT groups, respectively (P = 0.09). However, at the time of salvage treatment, the mean serum PSA levels were 9.1 and 1.1 ng/mL for the salvage RP and salvage RT groups, respectively (P = 0.0001). The mean time from tumor recurrence to salvage treatment was 15.6 months for the salvage RP group and 4.9 months for the salvage RT group (P = 0.0001 ). Although there was no statistical difference in the disease-free survival rate (P = 0.38), a trend for better disease control in the salvage RT group was evident (74.4% versus 44.4%). Patients treated with salvage RP had a higher rate of urinary incontinence than those undergoing salvage RT: 63% and 32.6%, respectively (P = 0.01).

CONCLUSIONS

The disease-free survival rate was similar between patients receiving salvage RP or RT, despite the significantly higher serum PSA levels at the time of treatment and the delay in time to treatment for the salvage RP patients. Salvage RP is associated with a high rate of urinary incontinence. Earlier identification of tumor recurrence after RT may improve the efficacy and safety of salvage RP.

Antibody responses in melanoma patients immunized with an anti-idiotype antibody mimicking disialoganglioside GD2

We initiated a clinical trial for patients with advanced malignant melanoma treated with an anti-idiotype antibody that mimics the disialoganglioside GD2. We report the clinical and immune responses of the first 12 patients entered into this trial. Patients received 1-, 2-, 4-, or 8-mg doses of the anti-idiotype antibody mixed with 100 microg of QS-21 adjuvant every other week, four times, and then monthly. Twelve patients have been on trial for 2-23 months, and all of them have generated immune responses. Patients were removed from the study if they demonstrated disease progression. Hyperimmune sera from all 12 patients revealed an anti-anti-idiotypic Ab3 response, as demonstrated by the inhibition of Ab2 binding to Ab1 by patients' immune sera. To further test the anti-anti-idiotypic response, patients' Ab3 antibodies were affinity purified on Sepharose 4B columns containing adsorbed immunizing anti-idiotype immunoglobulin. Purified Ab3 of all patients studied inhibited binding of Ab1 to a GD2-positive cell line. Purified Ab3 also inhibited binding of Ab1 to purified GD2, in a manner comparable to equal quantities of purified Ab1. The patient Ab3 was truly an Ab1' because it specifically bound to purified disialoganglioside GD2. The isotypic specificity of the Ab3 antibody was predominantly IgG, with only minimal IgM. The predominant IgG subclass was IgG1, with approximately equal quantities of IgG2, IgG3, and IgG4. These Ab3 antibodies reacted specifically with tumor cells expressing GD2 by immune flow cytometry and immunoperoxidase assays. Five patients' Ab3 antibodies studied for antibody-dependent cellular cytotoxicity were positive. One patient had a complete clinical response, with resolution of soft tissue disease, and six patients had stable disease, ranging from 9 to 23 months, and are being continued on vaccine therapy. Toxicity consisted of local reaction at the site of the injection, including induration and pain that generally resolved within a few days. Mild fever and chills were observed in 75% of the patients but rarely required acetaminophen. There was no additional toxicity, including abdominal pain that was previously seen with infusion of murine monoclonal anti-GD2 antibody. Current trials include patients with stage III melanoma and small cell lung cancer. Future trials will attempt to enhance the antitumor response by the addition of interleukin 2, granulocyte macrophage colony-stimulating factor, and other cytokines, together with the 1A7 vaccine.

Posttranslational regulation of Ty1 retrotransposition by mitogen-activated protein kinase Fus3

Ty1 retrotransposons in Saccharomyces cerevisiae are maintained in a state of transpositional dormancy. We isolated a mutation, rtt100-1, that increases the transposition of genomic Ty1 elements 18- to 56-fold but has little effect on the transposition of related Ty2 elements. rtt100-1 was shown to be a null allele of the FUS3 gene, which encodes a haploid-specific mitogen-activated protein kinase. In fus3 mutants, the levels of Ty1 RNA, protein synthesis, and proteolytic processing were not altered relative to those in FUS3 strains but steady-state levels of TyA, integrase, and reverse transcriptase proteins and Ty1 cDNA were all increased. These findings suggest that Fus3 suppresses Ty1 transposition by destabilizing viruslike particle-associated proteins. The Fus3 kinase is activated through the mating-pheromone response pathway by phosphorylation at basal levels in naive cells and at enhanced levels in pheromone-treated cells. We demonstrate that suppression of Ty1 transposition in naive cells requires basal levels of Fus3 activation. Substitution of conserved amino acids required for activation of Fus3 derepressed Ty1 transposition. Moreover, epistasis analyses revealed that components of the pheromone response pathway that act upstream of Fus3, including Ste4, Ste5, Ste7, and Ste11, are required for the posttranslational suppression of Ty1 transposition by Fus3. The regulation of Ty1 transposition by Fus3 provides a haploid-specific mechanism through which environmental signals can modulate the levels of retrotransposition.

A similar pattern of chromosomal alterations in prostate cancers from African-Americans and Caucasian Americans

A combination of genetic and epigenetic factors may explain the disproportionate incidence and mortality of prostate cancer among African-American males (AAMs) as compared with Caucasian American males (CAMs). We wished to determine whether primary prostate cancers from AAMs and CAMs harbor different patterns or frequencies of chromosomal alterations. Comparative genomic hybridization (CGH) was performed on clinically localized, untreated primary prostate cancers from 16 AAMs and 16 CAMs. Detailed statistical analysis was used to delineate gains and deletions with high sensitivity and specificity and to compare the frequency and pattern of alterations between the two groups of tumors. The two groups of patients had indistinguishable preoperative serum prostate-specific antigen levels, and the two groups of tumors had similar pathological stages and grades. Chromosomal gains and deletions occurred in regions known to be frequently altered in prostate cancer. Specifically, the most frequent alterations were deletions of regions on chromosomes 13q, 5q, 16q, and 8p and gains of regions on 8q and 5q. When tumors from AAMs and CAMs were compared, the frequencies of alteration (deletion, gain, or no alteration) were similar across 98.9% of the length of the genome. The patterns of alterations of the most frequently altered chromosomes were also similar between tumors from AAMs and CAMs. We concluded that primary prostate cancers from AAMs and CAMs harbor a similar pattern and frequency of chromosomal alterations. These data support the notion that sporadic prostate cancers from AAMs and CAMs develop by similar chromosomal mechanisms. Biological differences, if present, do not occur on the chromosomal level.

A clinicobacteriological study on leucorrhoea

The pathogens like Trichomonas vaginalis (4.5%), N gonorrhoeae (2.7%) and C albicans (6.7%) were exclusively present in leucorrhoea. The other potential agents with their respective percentages in normal women and cases of leucorrhoea were U urealyticum (21.2% and 50.2%), actinomyces (29.7% and 41.6%), Chlamydia trachomatis (17% and 48.8%), candida-like organisms (CLO) (1.2% and 9.5%) and non-group B streptococci (4.2% and 16.7%). The percentages of urethral syndrome (65.8%), vaginal irritation (63.4%), sore vulva (17%), cervicitis (13.4%), cervical erosion (11%) of the STD clinic were more than those of gynaecological cases. The latter group more often revealed infertility (15.8%) and pelvic inflammatory disease (13.6%). The exclusive isolation rate of N gonorrhoeae (7.3%) and prevalence of G vaginalis (19.5%) and Trichomonas vaginalis (8.5%) in the STD clinic were notable. The cases of gynaecological clinic more commonly showed C albicans (8%) and CLO (13.6%). Significant differences pertaining to U urealyticum (leucorrhoea and inapparent group p < 0.01; leucorrhoea and normal cases p < 0.01), M hominis (leucorrhoea and inapparent group p < 0.05; leucorrhoea and normal cases p < 0.01), Chlamydia trachomatis (leucorrhoea and normal cases p < 0.01) and also actinomyces (leucorrhoea and normal cases p < 0.01; inapparent and normal cases p < 0.05) were recorded. There was conspicuous association of U urealyticum, M hominis, G vaginalis, Chlamydia trachomatis, CLO and actinomyces with leucorrhoea. An almost exclusive presence of Staph aureus, Esch coli and Klebsiella in cases of leucorrhoea appeared meaningful.

Presence of circulating prostate cells in the bone marrow of patients undergoing radical prostatectomy is predictive of disease-free survival

PURPOSE

To determine whether the presence of circulating prostate cells in the bone marrow is associated with disease-free survival in patients undergoing radical prostatectomy.

MATERIALS AND METHODS

We evaluated the bone marrow of 86 patients with clinically localized prostate cancer treated by radical prostatectomy for the presence of circulating prostate cells using reverse-transcriptase polymerase chain reaction (RT-PCR) amplification of prostate-specific antigen (PSA) mRNA. Follow-up duration ranged from 1 to 43 months (mean, 15.4).

RESULTS

Two of 47 patients (4%) with negative RT-PCR PSA results and 10 of 39 patients (26%) with positive RT-PCR PSA results have had disease recurrence. Patients whose RT-PCR PSA results were positive had a significantly shorter disease-free survival period than those patients with negative RT-PCR PSA results (P = .004). RT-PCR status correlated significantly with serum PSA level (P = .001) and pathologic stage (P = .003). Based on Cox's proportional hazards models, RT-PCR status was found to be a significant predictor of disease-free survival. However, after controlling for PSA level, RT-PCR status was not significant in predicting disease-free survival.

CONCLUSION

RT-PCR PSA of bone marrow may be a useful pretreatment prognostic test for patients undergoing radical prostatectomy. Currently, this test should not be used to determine if patients receive definitive local therapy.

Prognostic implications of a positive apical margin in radical prostatectomy specimens

PURPOSE

We evaluated the prognostic implication of a positive surgical margin at the prostatic apex to define the risk of failure after radical prostatectomy.

MATERIALS AND METHODS

Radical prostatectomy specimens of 590 patients operated on between 1990 and 1994 were reviewed by 2 uropathologists (D. G. and W. S.) to determine the percentage of patients with a positive margin at the apex in the absence of positive margins, extraprostatic extension or involvement of seminal vesicles and pelvic lymph nodes. In this group of 33 patients, the significance of a positive apex could be determined without the influence of any other stage related prognostic factors. Treatment failure was defined as prostate specific antigen greater than 0.4. All 33 patients have been followed between 3.5 and 65.5 months (median 38.7).

RESULTS

Among 590 patients 236 (40%) had disease completely confined to the prostate. A total of 217 patients (37%) had either positive surgical margins (M+) or extraprostatic extension and of these, only 33 (5.5%) had an apical positive margin in an otherwise prostate confined tumor. Of 33 apical positive margin patients only 3 in whom surgery failed had progressively detectable prostate specific antigen 3.5 to 65.5 months after surgery.

CONCLUSIONS

A positive surgical margin at the prostatic apex in the absence of positive margins or extraprostatic extension elsewhere does not confer a worse prognosis than organ confined disease. In this study the recurrence rate for patients with positive apical margins was the same as for those with confined disease.

Incidence of urethral involvement in female bladder cancer: an anatomic pathologic study

OBJECTIVES

To evaluate risk factors for urethral involvement in female patients undergoing cystectomy for bladder cancer and to define potential candidates for orthotopic continent urinary diversion.

METHODS

From 1990 to 1996, 43 female patients underwent cystectomy for primary bladder malignancy. Bladder mapping studies were performed with special attention to tumor location, multifocality, pathologic stage and grade, presence of carcinoma in situ (CIS), and the relationship of these factors to urethral involvement.

RESULTS

Of the 43 patients evaluated, 7 (16.3%) had urethral involvement by tumor. Two patterns of urethral invasion were identified: 5 patients had tumors in the vascular or lymphatic channels of the periurethral tissue, and 2 had tumors in the mucosa or submucosa. Three of the 12 patients with tumors located at the trigone and 4 of the 26 with CIS of the bladder had tumor in the urethra. Three of the 5 patients with vaginal involvement had tumor in the urethra. Only vaginal involvement was significantly associated with urethral involvement (P = 0.02).

CONCLUSIONS

Vaginal involvement was the only preoperative factor that was associated with presence of tumor in the urethra. Five patients with urethral involvement had submucosal tumors without concomitant CIS of the urethra. Before the performance of orthotopic urinary diversions, intraoperative full-thickness bladder neck biopsies are needed to accurately evaluate the female urethra.

Interpreting kappa values for two-observer nursing diagnosis data

Reliability of nursing observations often is estimated using Cohen's kappa, a chance-adjusted measure of agreement between observer RNs. However, use of kappa as an omnibus measure sometimes can be misleading. In a study partly designed to describe the frequency and reliability of nursing diagnoses in long-term care facilities, 360 residents each were assessed independently by two registered nurses, and kappa and observed proportion of agreement were calculated as estimates of reliability. For some diagnoses we observed high proportions of agreement, yet paradoxically low kappa values. This article presents an in-depth statistical analysis to resolve this paradox. Results from our analysis also suggest means for planning improvements in the diagnostic performance of participating RNs. Consequently, our approach can be used in similar studies of diagnosis reliability to enhance nursing research, education, and practice.

Genetic variation in Asiatic lions and Indian tigers

Previous reports have suggested that Asiatic lions and tigers are highly inbred and exhibit very low levels of genetic variation. Our analyses on these species have shown much higher degrees of polymorphism than reported. Randomly amplified polymorphic DNA (RAPD) analysis of 38 Asiatic lions, which exist as a single population in the Gir Forest Sanctuary in India, shows an average heterozygosity of 25.82% with four primers. Sperm motility studies by our colleagues corroborate this data. In Indian tigers, microsatellite analysis of five CA repeat loci and multilocus fingerprinting using Bkm 2(8) probe on a population of 22 individuals revealed a heterozygosity of 22.65%. Microsatellite analysis of loci Fca 77 and Fca 126 revealed polymorphism amongst the Asiatic x African lion hybrids, which has enabled us to use these as markers to discriminate the pure Asiatic lions from the hybrids. A similar analysis was used to identify hybrids of Indian and Siberian tigers through polymerase chain reaction (PCR) amplification of hair samples. To ascertain the variation which existed before the population bottleneck at the turn of the present century, microsatellite analysis was performed on 50- to 125-year-old skin samples from museum specimens. Our results show similar levels of genetic variability as in the present population (21.01%). This suggests that low genetic variability may be the characteristic feature of these species and not the result of intensive inbreeding. DNA fingerprinting studies of Asiatic lions and tigers have helped in identifying individuals with high genetic variability which can be used for conservation breeding programs.

Theoretical study on naphthyl-phenylacetylenes for second-order nonlinear optical applications

The ground state dipole moments (μg), excited state dipole moments (μe), linear polarizabilities (α), first hyperpolarizabilities (β), and absorption maxima [Formula: see text] of a new series of 6,4′-disubstituted 2-naphthylphenylacetylenes have been calculated using the finite field – MNDO (Modified Neglect of Diatomic Overlap) technique and studied for second-order nonlinear optical (NLO) applications. Among all the molecules studied here, the strongest and the weakest electron donor/acceptor pairs [N(CH3)2/NO2] and [CH3/CN] exhibit the largest and the smallest βμ (projection of β on the axis of the μ) of 46.3 × 10−30 esu and 10.2 × 10−30 esu, respectively. The coefficients of the power law that describes the dependence of α and β on the number of conjugated bonds (n) were calculated for [NH2/NO2]n=1–5 and [NH2/CN]n=1–5 molecules. For β, exponents of 0.36 and 0.31 were obtained for [NH2/NO2]n=1–5 and [NH2/CN]n=1–5 molecules, respectively, and for α, an exponent of 0.37 was obtained for both series of molecules. A comparison is made between naphthylphenylacetylenes and diphenylacetylenes on the basis of their hyperpolarizabilities. Keywords: nonlinear optics, organic molecules, hyperpolarizabilities.

Localization of a 25 kDa human sperm surface protein: its role in in-vitro human sperm capacitation

A human endometrial sialic acid-binding glycoprotein (SABP) binds specifically to a 25 kDa protein on the plasma membranes of human non-capacitated sperm heads. In-vitro labelling of the sperm surface sialoglycoconjugates and subsequent incubation with SABP, suggests removal of some sialoglycoconjugate moieties from the sperm surface upon interaction with SABP. SABP also induces the exposure of mannose ligand receptors on the sperm surface and increases the production of superoxide anion (O2-).

Are there ethnic differences in deletions in the dystrophin gene?

We studied 160 cases of Duchenne muscular dystrophy (DMD) drawn from all parts of India, using multiplex PCR of 27 exons. Of these, 103 (64.4%) showed intragenic deletions. Most (69.7%) of the deletions involved exons 45-51. The phenotype of cases with deletion of single exons did not differ significantly from those with deletion of multiple exons. The distribution of deletions in studies from different countries was variable, but this was accounted for either by the small number of cases studied, or by fewer exons analyzed. It is concluded that there is likely to be no ethnic difference with respect to deletions in the DMD gene.

Transcriptional silencing of Ty1 elements in the RDN1 locus of yeast

We demonstrate that in Saccharomyces cerevisiae, the tandem array of ribosomal RNA genes (RDN1) is a target for integration of the Ty1 retrotransposon that results in silencing of Ty1 transcription and transposition. Ty1 elements transpose into random rDNA repeat units and are mitotically stable. In addition, we have found that mutation of several putative modifiers of RDN1 chromatin structure abolishes silencing of Ty1 elements in the rDNA array. Disruption of SIR2, which elevates recombination in RDN1, or TOP1, which increases psoralen accessibility in rDNA, or HTA1-HTB1, which reduces histone H2A-H2B levels and causes localized chromatin perturbations, abolishes transcriptional silencing of Ty1 elements in RDN1. Furthermore, deletion of the gene for the ubiquitin conjugating enzyme Ubc2p, which ubiquitinates histones in vitro, derepresses not only Ty1 transcription but also mitotic recombination in RDN1. On the basis of these results, we propose that a specialized chromatin structure exists in RDN1 that silences transcription of the Ty1 retrotransposon.

Polymerase chain reaction-based diagnosis of del (5q) in acute myeloid leukemia and myelodysplastic syndrome identifies a minimal deletion interval

Loss of all or part of the long arm of human chromosome 5 is a recurrent abnormality in patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), especially after chemotherapy for a prior malignancy. It is one of the worst prognostic indicators in AML, associated with chemotherapy resistance and short survival. These deletions center at band 5q31, which has thus been proposed as the location of a tumor suppressor gene; this site is to be distinguished from that observed in 5q- syndrome, centering at 5q32. To define the molecular extent and the clinical prevalence of 5q31 deletions, we collected a series of AML and MDS cases of mixed karyotype, taking care to exclude MDS cases with 5q- syndrome. The samples were analyzed for loss of heterozygosity (LOH) using a panel polymerase chain reaction (PCR)-based microsatellite markers from 5q, comparing malignant cells with normal tissue derived from lymphoblastoid cell lines or buccal mucosa scrapings. Losses were detected in seven of 29 matched samples, including four of 17 with MDS, and three of 12 with AML; six of these seven also had a cytogenetically-visible del(5q) or -5. The one case without a cytogenetic deletion showed molecular loss of three contiguous markers, with retention of flanking markers interleukin-9 (IL-9) and D5S414, and thus contained a small deletion that is below cytogenetic resolution. PCR failed to detect 5q loss in two cases with large cytogenetic deletions, but both had been treated and contained low percentages of malignant cells in the samples. This study thus led to the identification of a case with a minimal deletion for the 5q31 tumor suppressor gene, specified by IL-9-D5S414, that is approximately 1 Mb (2 cM) in extent. Additionally, we demonstrate that PCR-based allelotyping is a reliable method for the detection of chromosomal deletion in myeloid malignancy, providing the specimens contain a high proportion of malignant cells. These studies will help to identify the tumor-suppressor gene at 5q31, and will help to develop molecular methods for diagnosis and monitoring of these disorders.

The Mu strong gyrase-binding site promotes efficient synapsis of the prophage termini

A strong DNA gyrase-binding site (SGS) is located midway between the termini of the bacteriophage Mu genome and is required for efficient replicative transposition. We have proposed that the SGS promotes the efficient synapsis of the Mu prophage ends (an obligate early step in replicative transposition), and that it does so by helping to organize the prophage DNA into a supercoiled loop with the SGS at the apex of the loop and the prophage termini at the base. The positioning of the synapsing termini equidistant from the SGS is a key element in the proposed model. To test this proposal, we have constructed prophages with a second, internal right end and asked whether the natural, external right end or the internal right end is used for synapsis with the left end in the presence and absence of the SGS. In the presence of the central SGS, the natural, or outside, right end was used exclusively and very efficiently. In the absence of the central SGS, the internal right end was used preferentially and inefficiently: the efficiency of transposition decreased with increasing distance between the internal right end and the left end. Repositioning the SGS midway between the left end and an internal right end allowed highly efficient use of the internal right end. These results support a model in which gyrase can influence long-range DNA interactions to promote efficient synapsis of Mu prophage ends.