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J L Mohler

Publications and source records attributed to J L Mohler.

At least 19 recordsLinked to original sources
PubMed1995

Genetic instability assessed by sister chromatid exchange analysis in the Dunning R-3327 rat prostatic adenocarcinoma model and its relationship to metastatic potential.

The original Dunning R-3327 tumor, described in 1961, has given rise to distinct sublines of different metastatic potentials. The different phenotypes cannot be explained by differences in chromosomal number, DNA content, or nuclear pleomorphism. Sister chromatid exchange is an interchange between two strands of DNA indicative of DNA damage. The frequency of sister chromatid exchanges is a well-accepted measure of genetic instability. To determine whether an assay of genetic instability could distinguish sublines capable of generating cells of the metastatic phenotype, cells from three sublines of low (< 10%) metastatic potential and three sublines of high (> 90%) metastatic potential were cultured in 10 microM 5-bromodeoxyuridine to label DNA. Chromosome preparations were made and sister chromatids were differentiated with Hoechst 33258 dye and Giemsa stain. Sixty metaphase spreads from each subline were scored for SCE and chromosome number. The low metastatic sublines G, AT-1, and AT-2 had 0.32 +/- standard deviation 0.10, 0.38 +/- 0.12, and 0.14 +/- 0.05 sister chromatid exchanges per chromosome, respectively. The high metastatic sublines AT-3, MAT-Lu, and MAT-LyLu had 0.55 +/- 0.17, 0.32 +/- 0.1, and 0.33 +/- 0.2 sister chromatid exchanges per chromosome, respectively. Subline differences in metastatic potentials cannot be explained by incidences of sister chromatid exchanges.

Adenocarcinoma↗
PubMed1995

Detection of candidates for cancer cell motility inhibitory protein in the Dunning adenocarcinoma model.

The more differentiated components of a primary tumor may produce substances that reduce the growth rate and metastatic potential of more aggressive components. In the Dunning R-3327 prostatic adenocarcinoma model, cancer cell motility is required for metastatic potential. Medium conditioned by the non-motile, non-metastatic G subline contains proteins of molecular weight 50-100 kDa that inhibited the motility of the highly motile, highly metastatic MAT-LyLu subline. G subline-conditioned medium was separated by DEAE-cellulose chromatography using a linear gradient of 0-0.5 M NaCl in 100 mM Tris at pH 8.3. The motility inhibitory activity of G-conditioned medium was localized to column fractions 51-70 that contained 18% of the applied protein and only 6.5% of the proteins secreted by the G cells. Analysis of pooled fractions 51-60 and 61-70 by two-dimensional gel electrophoresis identified five protein families, with a total of 12 charged proteins of molecular weights approximating 66, 54, 50, 41 and 34 kDa, that were not present or present in reduced quantities in column fractions that did not inhibit motility. Isolation and identification of motility inhibitory protein may prove it the first substance discovered that is produced by a more differentiated component of a neoplasm that directly inhibits a metastasis-associated property.

Adenocarcinoma↗
PubMed1995

Selection of men at high risk for disease recurrence for experimental adjuvant therapy following radical prostatectomy.

OBJECTIVES: Following surgery, men with recurrent prostate cancer have an isolated elevation in serum prostate-specific antigen (PSA) well in advance of measurable metastatic disease. Rational patient selection for new forms of adjuvant therapy, for example, gene therapy, is imperative. METHODS: In a retrospective study of two cohorts, we used proportional hazards regression analysis to develop and validate a multifactor model for identifying men who are at high risk of cancer recurrence. The model cohort consisted of 216 men with clinical Stage T2b and T2c treated by 1 urologist. The validation cohort consisted of 214 men with Stage T2b and T2c disease. RESULTS: A model for log relative risk, Rw, used serum PSA with a sigmoidal transformation (PSAST), radical prostatectomy Gleason score (GS), and pathologic stage (PS) as specimen confined or nonspecimen confined: Rw = (PSAST x 0.06) + (GS x 0.54) + (PS x 1.87). Recurrence risk categories were determined as low risk if Rw is less than 4.0, intermediate risk if it is 4.0 to less than 5.75, and high risk if Rw is more than 5.75. The observed Kaplan-Meier actuarial analysis of the three risk groups correlated well with the predictions determined for the model cohort. We then validated this model independently using a second cohort of 214 men with similar age, stage, and grade treated by 3 different urologists at two different institutions. CONCLUSIONS: The recurrence rates for men in the high-risk group are similar to those for men with positive lymph nodes and justifies exploration of experimental adjuvant therapy within this group using this model of patient selection.

Actuarial Analysis↗
PubMed1995

Outpatient pelvic lymph node dissection.

PURPOSE: Staging pelvic lymph node dissection is an important part of the evaluation of most patients with prostatic carcinoma. While laparoscopic pelvic lymph node dissection provides an alternative to standard pelvic lymph node dissection, it has been associated with a significant learning curve, high major complication rate, frequent hospitalization and greater expense. We sought to modify the technique of pelvic lymph node dissection to allow its performance as an outpatient procedure. MATERIALS AND METHODS: Pelvic lymph node dissection was performed through bilateral 3 cm. incisions overlying the obturator fossa in 11 patients. RESULTS: Nodes sampled ranged from 5 to 26 per patient that differed insignificantly from those undergoing standard pelvic lymph node dissection. Four patients had lymph node metastases. Nine procedures were performed entirely on an outpatient basis. One complication (external vein injury) was repaired with a single suture after extending the incision to 6 cm. CONCLUSIONS: Outpatient pelvic lymph node dissection through small incisions provides an attractive alternative to standard or laparoscopic lymph node dissection. With further experience it may become the procedure of choice for staging prostatic carcinoma in patients with a high risk of pelvic lymph node metastases.

Aged↗
PubMed1995

Partial adrenalectomy for renal cell carcinoma with bilateral adrenal metastases.

Resection of the adrenal glands precludes participation in many immunotherapy protocols for metastatic renal cell carcinoma. We performed radical nephrectomy with adrenalectomy and contralateral partial adrenalectomy, including adrenal vein ligation for a 4 cm. hilar metastasis without perioperative complications or local recurrence after 30 months. Adrenal function, measured by cosyntropin stimulation tests 6 weeks and 10 months postoperatively, was normal. Partial adrenalectomy with preservation of adrenal function is possible.

Adrenal Gland Neoplasms↗
PubMed1994

Nuclear shape analysis for the assessment of local invasion and metastases in clinically localized prostate carcinoma.

BACKGROUND: Nuclear shape analysis of histologic sections from radical prostatectomy specimens has retrospectively predicted outcome in patients with clinically localized prostate carcinoma. If outcome could be predicted preoperatively by nuclear shape analysis, patients might be selected better for definitive surgical therapy. Morphometric analysis of preoperative biopsies, however, has not correlated positively with values obtained from analysis of prostatectomy specimens. METHODS: The nuclear shapes of histologic specimens of 20 organ-confined carcinomas, 10 periprostatic fat-invasive carcinomas, 10 seminal vesicle-invasive carcinomas, and 12 lymph node-metastatic carcinomas from 52 patients who had undergone radical prostatectomy for clinically localized disease were evaluated. RESULTS: Nuclei from areas of extraprostatic invasion or regional lymph node metastases were less round than those from the corresponding intraprostatic portion of the tumor (nuclear roundness factor (mean +/- SD) PPF, 51.2 +/- 3.1 vs. 31.2 +/- 3.2; SV, 52.4 +/- 4.1 vs. 31.6 +/- 2.5; and LN, 57.3 +/- 3.1 vs. 36.4 +/- 1.8; paired Student's t tests, P < 0.001). Cells sampled from the periphery of organ-confined tumors had a greater nuclear roundness factor (49.1 +/- 1.5) than did those sampled from the center (34.5 +/- 2.0; P < 0.001) or randomly throughout the tumor (37.8 +/- 1.6; P < 0.001). Nuclear roundness factors for all extraprostatic tumor foci and for peripheral tumor cells in organ-confined disease were similar (analysis of variance, P > 0.05). The intraprostatic portions of randomly sampled primary tumors had similar nuclear roundness factors, regardless of pathologic stage (P > 0.05). Among organ-confined carcinomas, nuclear shape was unrelated to tumor volume. CONCLUSIONS: Pathologic stage in clinically localized prostate carcinoma cannot be determined by the nuclear shape profiles of intraprostatic tumor cells. Thus, patients with a poor prognosis or high pathologic stage can be recognized only when samples for morphometric analysis include high proportions of nuclei from the extra-prostatic carcinoma and nuclei from the periphery of organ-confined carcinoma that may not be sampled routinely by prostate biopsy.

Adipose Tissue↗
PubMed1994

Elevation of topoisomerase I messenger RNA, protein, and catalytic activity in human tumors: demonstration of tumor-type specificity and implications for cancer chemotherapy.

Topoisomerase I has been identified as an intracellular target of camptothecin, a plant alkaloid with anticancer activity. Various lines of evidence suggest that the sensitivity of cells to this drug is directly related to the topoisomerase I content. In humans, the levels of topoisomerase I have been shown to be elevated in colorectal tumors, compared to normal colon mucosa. The aim of our study was to determine whether (a) topoisomerase I levels are elevated in other solid tumors, (b) the elevated enzyme is catalytically active in these tumors, and (c) the increase in topoisomerase I levels in colorectal tumors is a result of increased transcription or translation. Topoisomerase I levels were quantitated in crude extracts from colorectal, prostate, and kidney tumors and their matched normal counterparts by Western blotting and by direct determination of catalytic activity, and mRNA levels were determined by Northern blotting. By Western blotting, colorectal tumors showed 5-35-fold increases in topoisomerase I levels, compared to their normal colon mucosa. In the case of prostate tumors, the increase was 2-10-fold, compared with benign hyperplastic prostate tissue from the same patients. However, no difference was observed in topoisomerase I levels in kidney tumors, compared to their normal counterparts. The catalytic activity of topoisomerase I was determined by a quantitative 32P-transfer assay in crude homogenates, without isolating nuclei. Colorectal and prostate tumors exhibited 11-40- and 4-26-fold increases, respectively, in catalytic activity. However, kidney tumors did not show any alteration in catalytic activity, compared to their normal matched samples. Thus, for all three tumor types there was a good correlation between enzyme levels and catalytic activity. Finally, colorectal tumors were analyzed for steady state mRNA levels. A 2-33-fold increase in mRNA levels was found in colorectal tumors, compared to normal colon mucosa. These results suggest that alterations in topoisomerase I expression in humans are tumor type specific and that the increase in topoisomerase I levels results from either increased transcription of the topoisomerase I gene or increased mRNA stability.

Amino Acid Sequence↗
PubMed1994

Coumarin (1,2-benzopyrone) for the treatment of prostatic carcinoma.

The unavailability of effective treatment for metastatic hormone-refractory and clinically localized but pathologically unfavorable prostatic carcinoma warrants trial of new and promising treatments. Preliminary studies in patients with metastatic disease have shown (a) subjective but no objective responses to 100 mg coumarin and cimetidine daily; (b) objective responses in 3 of 40 patients treated with 3 g coumarin daily, all of whom had normal performance status and 1 of whom remains with three resolved bone metastases and stable prostate-specific antigen levels after 4 years; (c) toxicity only in bedridden patients. We recently initiated two multi-center trials of 1 g coumarin daily. Metastatic prostatic carcinoma patients of normal performance status were treated in a phase II trial. Patients who had been treated by radical prostatectomy, but had surgical margin, seminal vesicle or lymph node involvement or detectable prostate-specific antigen after radical prostatectomy, were randomized to coumarin or placebo.

Aged↗
PubMed1994

An updated review of the clinical development of coumarin (1,2-benzopyrone) and 7-hydroxycoumarin.

Several authors have demonstrated that coumarin (1,2-benzopyrone) in combination with cimetidine can produce objective antitumor responses in some patients with advanced renal cell carcinoma. The purpose of this report is to review the clinical development of coumarin, with or without cimetidine, with special reference to renal cell carcinoma (RCC). Previously unpublished data concerning the survival of a population of patients with RCC, who were treated on a phase I trial of coumarin and cimetidine, are presented. The rationale and study design of an active randomized, double-blinded, placebo-controlled trial of coumarin for RCC are discussed. A progress report is given for an ongoing phase I trial of oral 7-hydroxycoumarin, the major human metabolite of coumarin.

Adult↗
PubMed1994

Effects of alpha-adrenergic agonist on neobladder water and electrolyte transport.

OBJECTIVE: Nocturnal urinary incontinence and nocturia are problematic for patients with continent neobladders. Clonidine, an alpha 2-adrenergic agonist, increases water absorption across rabbit ileum; human intestine contains a substantial density of alpha 2-adrenergic receptors. We studied the effect of neobladder clonidine instillation and catheterization (to reduce urine-bowel contact time) on nocturnal water and electrolyte reabsorption. METHODS: A total of 8 patients with Indiana neobladders constructed after radical cystectomy were studied at a mean of 11.3 months postoperatively under standardized diet and fluid intake. RESULTS: Topical clonidine or catheterization failed to alter nocturnal urine volume, free-water clearance, or absolute excretions of electrolytes in Indiana neobladders; however, the absolute excretion of urine urea nitrogen and osmoles was significantly increased in the catheterized urine collections compared with the baseline urine collections (paired t-test, p = 0.0022 and 0.0091, respectively). CONCLUSIONS: Bowel comprising neobladders loses its capacity to significantly alter urinary electrolyte composition by prolonged contact, which may explain the rarity of significant acid-base disturbances in patients with continent neobladders. Unfortunately, topical clonidine does not diminish nocturnal urine volumes, but increased excretion of urea and osmoles with overnight neobladder catheterization may prove beneficial in patients who suffer azotemia or hyperosmolarity.

Adult↗
PubMed1994

Collagen cross-link metabolites in urine as markers of bone metastases in prostatic carcinoma.

The efficacy of radionuclide bone scans in monitoring metastatic bone activity remains controversial. Objective measurement of bone tumor burden would be useful for the evaluation of new therapies for metastatic carcinoma of the prostate. The recent discovery of the urinary excretion of pyridinoline (cross-link of mature collagen found in cartilage and bone) and deoxypyridinoline (collagen cross-link specific to bone) measured by high pressure liquid chromatography has provided sensitive specific indexes of cartilage and bone breakdown in rheumatoid arthritis, osteoporosis and metabolic bone diseases. We compared the urinary excretion of deoxypyridinoline,pyridinoline and hydroxyproline relative to urinary creatinine (nmol./mmol.creatinine) in 27 patients with benign prostatic hyperplasia (patient age 70.0 +/- 8.5 years, standard deviation), 29 with clinically confined prostate cancer (age 70.2 +/- 9.7 years), and 26 with prostate cancer and bone metastases (age 71.1 +/- 7.7 years). No diurnal variation of deoxypyridinoline or pyridinoline urinary excretion was detected in 5 patients with metastases. Urinary excretion of pyridinoline and deoxypyridinoline was significantly greater in patients with metastatic carcinoma of the prostate compared with patients with either benign prostatic hyperplasia (Mann-Whitney-Wilcoxon rank sum analysis, p < 0.00004 and 0.002, respectively) or localized prostate cancer (Mann-Whitney-Wilcoxon, p < 0.00001 and 0.00005, respectively). Urinary hydroxyproline levels failed to separate the 3 groups. Pyridinoline and deoxypyridinoline excretion in prostate cancer patients with metastases directly correlated with bone scan Soloway scores (r = 0.55, p < 0.005 and r = 0.57, p < 0.004 respectively), whereas serum prostate specific antigen did not (r = 0.36, p = 0.08). Serial measurements of pyridinoline and deoxypyridinoline progressively increased in 3 patients with clinical progression documented by new metastatic lesions by bone scan. Measurement of pyridinoline and deoxypyridinoline excretion cannot diagnose metastatic disease. However, these markers should be evaluated further for quantitative assessment of bone metastases.

Aged↗
PubMed1994

Expression of human prostatic acid phosphatase and prostate specific antigen genes in neoplastic and benign tissues.

Expression of human prostatic acid phosphatase (ACPP) and prostate specific antigen (PSA) genes in prostatic carcinoma (CAP) and benign prostatic hyperplasia (BPH) was investigated by northern blot analyses. The expressions of ACPP and PSA, as well as the glycolytic enzymes glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and lactate dehydrogenase-muscle (LDH-A), were elevated significantly in prostatic carcinoma when compared with the expressions of these genes in benign prostatic hyperplasia in the same patient. The expression of the actin gene in both neoplastic and benign hyperplasia remained the same.

Acid Phosphatase↗
PubMed1994

Semiautomated nuclear shape analysis of prostatic carcinoma and benign prostatic hyperplasia.

Nuclear shape analysis has predicted outcome better than histologic grading in patients with clinically localized prostatic carcinoma. However, the requirement for manual nuclear contour tracing makes the method tedious and slow. Currently available image analysis systems for nuclear shape analysis using light-absorption microscopy provide nuclear boundaries of insufficient clarity for automatic segmentation. We improved image resolution using confocal laser scanning microscopy, automatically detected nuclear boundaries by a multiscale segmentation algorithm and discriminated artifacts in a semiautomated way. A manual quantitative morphometry system and our semiautomated system distinguished eight cases of prostatic carcinoma from seven cases of benign prostatic hyperplasia by nuclear roundness factor, ellipticity, nuclear area and perimeter. The ease of semiautomated nuclear shape analysis should allow evaluation of large numbers of patients with known outcomes after treatment for clinically localized prostatic carcinoma to determine whether nuclear shape analysis can be extended from research to clinical usage.

Carcinoma↗
PubMed1994

Nuclear morphometry in automatic biopsy and radical prostatectomy specimens of prostatic carcinoma. A comparison.

Nuclear shape analysis performed upon prostatectomy specimens of prostatic carcinoma distinguished individual patients with good and poor prognoses. In order to be useful for prognosis assessment preoperatively, nuclear morphometry must be measured on needle biopsy specimens. We compared nuclear morphometry on automatic biopsy and radical prostatectomy specimens in 20 patients with prostatic carcinoma. Nuclear size was smaller (paired Student t test, P < .0001) in biopsy specimens (perimeter 17.0 +/- SD 4.9 microns, area 29.9 +/- 6.6 microns2) than in prostatectomy specimens (perimeter 24.6 +/- 4.4 microns, area 48.2 +/- 8.7 microns2). Nuclear shape was more abnormal in automatic biopsy specimens (nuclear roundness factor 82.0 +/- 18.8, ellipticity 90.5 +/- 27.7) than in surgical specimens (nuclear roundness factor 43.5 +/- 8.8, ellipticity 54.0 +/- 14.7) (P < .0001). Study of specimens obtained by automatic biopsy preoperatively and automatic biopsy of the prostatectomy specimens at various steps of processing revealed that nuclear swelling and rounding occurred after 2-24 hours of formalin fixation. Automatic prostate biopsies may more accurately reflect true nuclear morphometry and should be studied for preoperative prognosis prediction in patients with clinically localized prostatic carcinoma.

Biopsy↗
PubMed1993

Genetic risk and carcinogen exposure: a common inherited defect of the carcinogen-metabolism gene glutathione S-transferase M1 (GSTM1) that increases susceptibility to bladder cancer.

BACKGROUND: Numerous studies have associated bladder cancer with exposure to carcinogens present in tobacco smoke and other environmental or occupational exposures. Approximately 50% of all humans inherit two deleted copies of the GSTM1 gene which encodes for the carcinogen-detoxification enzyme glutathione S-transferase M1. Recent findings suggest that the GSTM1 gene may modulate the internal dose of environmental carcinogens and thereby affect the risk of developing bladder cancer. PURPOSE: We investigated whether the absence of the GSTM1 gene affects bladder cancer risk and whether there are racial differences in GSTM1 genotype frequency. METHODS: Using a polymerase chain reaction (PCR)-based method, we examined the frequency of the homozygous deleted genotype (GSTM1 0/0) in 229 patients with transitional cell carcinoma of the bladder and 211 control subjects who were enrolled from the Urology Clinics at Duke University Medical Center and the University of North Carolina Hospitals. Control subjects were urology clinic patients who primarily presented with benign prostatic hypertrophy or impotence, who had no history of any cancer other than nonmelanoma skin cancer, and who were frequency matched to case patients on race, sex, and age (10-year age intervals). In order to explore racial differences in GSTM1 gene frequency, genotype was also determined in a community-based sample of 466 paid, healthy, unrelated volunteers from Durham and Chapel Hill, N.C. The presence or absence of the GSTM1 gene locus was determined by using a differential PCR, a semiquantitative technique in which multiple genes are coamplified. RESULTS: Overall, the GSTM1 0/0 genotype conferred a 70% increased risk of bladder cancer (odds ratio [OR] = 1.7; 95% confidence interval [CI] = 1.2-2.5; P = .004). Absence of the GSTM1 gene encoding the glutathione S-transferase M1 enzyme significantly increased risk to persons with exposure to the carcinogens in tobacco smoke (OR = 1.8; 95% CI = 1.2-3.0; P = .01) but poses little increased risk to persons without such exposure. Persons with smoking exposure of more than 50 pack-years who had the GSTM1 0/0 genotype had a sixfold greater risk relative to persons in the lowest risk group (i.e., nonsmokers who were GSTM1 +/+ or +/0). In the pooled clinic control and community sample groups (677 individuals), the GSTM1 0/0 genotype occurred less frequently among Blacks (35%) than among Whites (49%, P < .001). CONCLUSIONS: These findings support a protective role for the GSTM1 gene in bladder cancer. From these findings, it is estimated that 25% of all bladder cancer may be attributable to the at-risk GSTM1 0/0 genotype.

Base Sequence↗
PubMed1993

Flow cytometric assay of pinocytosis: correlation with membrane ruffling and metastatic potential in the Dunning R-3327 rat prostatic adenocarcinoma model.

Membrane ruffling has been associated with neoplastic transformation, Harvey ras expression, and metastatic capability. In the Dunning R-3327 rat prostatic adenocarcinoma model, membrane ruffling graded visually upon live cultured cells filmed by time-lapse video-microscopy has distinguished sublines of high and low metastatic potential. Fluid-phase pinocytosis is a constitutive, noninducible internalization of medium by cell membrane. Fluid phase pinocytosis may be measured flow cytometrically by cellular uptake of fluorescein-labelled medium constituents. The optimum conditions for a flow cytometric assay of pinocytosis were determined using AT-2 subline that has an intermediate degree of membrane ruffling. The optimum dextran concentration was selected from the midpoint of the linear portion of the dose-response (0.01-10.00 mg/ml) curve, whereas the optimum incubation time was determined from a time-course (1-405 min.) curve study. Cultured cells from 6 Dunning sublines incubated with 1.0 mg/ml of fluorescein-labelled dextran for 90 min were washed, fixed, and the fluorescence of 10,000 cells studied by flow cytometry. For each subline, dextran fluorescence was measured in four independent experiments. Pinocytosis failed to distinguish sublines of high (AT-3 63.5 +/- standard error 4.1 mean channel number, MAT-LyLu 63.2 +/- 6.3, MAT-Lu 64.3 +/- 5.6) and low (G 33.5 +/- 1.2, AT-1 63.5 +/- 4.1, AT-2 58.4 +/- 3.6) (rank p = 0.38) metastatic potential but correlated strongly with visually graded membrane ruffling (r = 0.95, p = 0.003). Pinocytosis assayed by flow cytometry reflects membrane ruffling observed visually and thus flow cytometric assays may facilitate study of membrane activity.

Adenocarcinoma↗