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Biomedical subjects

A T Cockett

Publications and source records attributed to A T Cockett.

At least 19 recordsLinked to original sources
PubMed1992

Prostate specific antigen predominantly forms a complex with alpha 1-antichymotrypsin in blood. Implications for procedures to measure prostate specific antigen in serum.

BACKGROUND: Prostate specific antigen (PSA) is a zymogen of a 33-kilodalton (kD) serine proteinase with extensive similarity to glandular kallikreins. The mechanism responsible for converting the zymogen into active proteinase has not been defined, but active PSA may be irreversibly inactivated in vitro by two of the major proteinase inhibitors in blood: alpha 1-antichymotrypsin and alpha 2-macroglobulin. METHODS: Procedures have been designed to characterize the different molecular forms of PSA in serum. One assay detects PSA epitopes available on both PSA binding to serine proteinase inhibitors and PSA not binding to a proteinase inhibitor. A second assay only detects PSA in complex with alpha 1-antichymotrypsin. A third assay mainly detects PSA not binding to a proteinase inhibitor. RESULTS: In serum samples, an 80-kD to 90-kD species of PSA in complex with alpha 1-antichymotrypsin is the predominant molecular form and a minor molecular form of serum PSA was an approximately 30-kD fraction not binding to a proteinase inhibitor. CONCLUSIONS: The benefits of detecting different molecular forms of serum PSA should be investigated regarding possibilities to facilitate differential diagnosis of carcinoma of the prostate (CAP) and benign prostatic hyperplasia (BPH).

Antigens, Neoplasm↗
PubMed1992

Indications for treatment of benign prostatic hyperplasia. The American Urological Association Study.

BACKGROUND: In 1990, a pilot study was begun that evaluated benign prostatic hyperplasia (BPH) at five clinical institutions. Data management and coordination of this study was performed at the Medical Practices Evaluation Center at Massachusetts General Hospital. Because of decreased patient enrollment, one institution was dropped. This was a randomized, prospective, clinical study that provided an initial overview of the trial and a rationale for the project. METHODS: Patients with clinically significant signs and symptoms of BPH were enrolled in this study. A symptom index consisting of seven items was used to document patient complaints of prostatic enlargement. Prostate size was determined using ultrasonography. Uroflowmetry (peak flow and mean flow) and residual urine volumes were documented. Abdominal ultrasonography was performed to rule out the presence of a dilated upper urinary tract. Cystoscopy was completed to determine the extent of prostatic and bladder neck obstruction. Trabeculations or cellules in the bladder, if present, were also documented. Conclusions. Preliminary results were obtained. The operative and nonoperative options depending on prostate size are shown in the figures of this article. The use of an interactive video disc has been beneficial in explaining the risks and benefits of each treatment option applicable to the patient in this randomized, controlled study.

Aged↗
PubMed1992

The effect of varicocelectomy on testicular volume in 89 infertile adult males with varicoceles.

The presence of a varicocele has been associated with reduced testicular volumes both in the adult and pediatric patient populations. An increase in testicular volume after varicocelectomy, however, has been documented only in the latter group and then only in the ipsilateral testicle. We present our experience with 89 infertile male patients with varicoceles who underwent operative repair. An increase in testicular volume was observed in 72 of the 89 patients, with the right side showing a greater increase, regardless of whether bilateral or unilateral left varicoceles were present preoperatively. No greater increase in testicular volume was noted among the patients who went on to achieve a pregnancy with their spouses. In addition, the age of the patient did not influence the observed change in testicular volume. No correlation between varicocele grade and pregnancy nor between improvement in semen parameters and improvement in testicular volume could be demonstrated.

Adult↗
PubMed1992

The American Urological Association symptom index for benign prostatic hyperplasia. The Measurement Committee of the American Urological Association.

A symptom index for benign prostatic hyperplasia (BPH) was developed and validated by a multidisciplinary measurement committee of the American Urological Association (AUA). Validation studies were conducted involving a total of 210 BPH patients and 108 control subjects. The final AUA symptom index includes 7 questions covering frequency, nocturia, weak urinary stream, hesitancy, intermittence, incomplete emptying and urgency. On revalidation, the index was internally consistent (Cronbach's alpha = 0.86) and the score generated had excellent test-retest reliability (r = 0.92). Scores were highly correlated with subjects' global ratings of the magnitude of their urinary problem (r = 0.65 to 0.72) and powerfully discriminated between BPH and control subjects (receiver operating characteristic area 0.85). Finally, the index was sensitive to change, with preoperative scores decreasing from a mean of 17.6 to 7.1 by 4 weeks after prostatectomy (p < 0.001). The AUA symptom index is clinically sensible, reliable, valid and responsive. It is practical for use in practice and for inclusion in research protocols.

Adult↗
PubMed1992

Suramin inhibits gonadotropin action in rat testis: implications for treatment of advanced prostate cancer.

Suramin is being evaluated for the treatment of metastatic prostate cancer based on its inhibition of growth factor action. In addition, suramin may inhibit the endocrine control of androgen production, which was explored herein. Adult Sprague-Dawley rats were injected (i.p.) daily with varying doses of suramin. At a cumulative dose of 200 mg., suramin significantly depressed serum testosterone (p less than 0.05), and follicle stimulating hormone (p less than 0.002) levels. In vitro studies showed that suramin-mediated suppression of androgen production might be secondary to inhibition of gonadotropin action. In MA-10 cell cultures, suramin inhibited a maximum stimulatory dose of human chorionic gonadotropin with an ED50 of 4.4 microM. Studies in rat Sertoli cell cultures showed that follicle stimulating hormone action was also inhibited by suramin, with an ED50 of 8.6 microM. Using receptor binding assays with calf testis membrane, we showed that suramin inhibited 125I-hFSH binding to receptor in a dose dependent fashion with an ED50 of 10.4 microM; comparable to the ED50 of suramin inhibition of follicle stimulating hormone action in Sertoli cell culture cells. Thus the mechanism of suramin's suppression of androgen production may involve multiple sites of action, including inhibition of gonadotropin binding to its receptor and suppression of pituitary gonadotropin levels in serum. This inhibition of androgen production may be useful in the treatment of advanced prostate cancer.

Animals↗
PubMed1991

DNA slit-scan flow cytometry of bladder irrigation specimens and the importance of recognizing urothelial cells.

DNA slit-scan flow cytometry was used to analyze 150 bladder irrigation specimens from 83 patients. Specimens were categorized into groups based on cystoscopy, histology, and cytopathology. Cells were stained for DNA with propidium iodide using a whole cell protocol. Non-specific fluorescence in the cytoplasm of some urothelial cells together with differential DNA staining of cell types in certain specimens was noted. DNA frequency distributions were analyzed using a semi-automated technique. Data were gated using slit-scan morphological features to remove cellular debris, multiple nuclei, and cells exhibiting nonspecific cytoplasmic fluorescence. Specimens were classified abnormal if they were aneuploid or had a hyperdiploid fraction (HDF) greater than 8%. The sensitivity to abnormality was 89% for grade 3 transitional cell carcinoma (TCC), 70% for grade 2 TCC, and 67% for grade 1 TCC. Specificity was 61%. Specimen data were then reprocessed using slit-scan morphological features to enrich for urothelial cells. The urothelial cells were identified by the ratio of nuclear diameter to cell diameter. This method was found to be in good agreement with immunofluorescent labeling of urothelial cells using the urothelium-selective T16 monoclonal antibody. The sensitivity to abnormality remained 89% for grade 3 TCC and 70% for grade 2 TCC, but fell to 52% for grade 1 TCC. Specificity for the urothelial cell enriched data increased to 77%. Reprocessing of data to enrich for urothelial elements resulted in 16 fewer specimens with an aneuploid DNA distribution and 2 fewer specimens with increased HDF.(ABSTRACT TRUNCATED AT 250 WORDS)

Aneuploidy↗
PubMed1991

Bacillus Calmette-Guerin and interleukin-2 for treatment of superficial bladder cancer.

A total of 22 patients with bladder cancer received bacillus Calmette-Guerin (BCG) and interleukin-2. Significant bladder tumor remissions were noted in 15 of 17 patients (88%). Of 5 patients with carcinoma in situ 1 was noncompliant and he died of carcinoma in situ. The other 4 patients are in remission. BCG alone was instilled in 22 additional patients with superficial bladder cancer. The remission rates were encouraging. Of the 22 patients 13 (59%) had remission of the bladder tumor. A half dose of BCG (60 mg.) is adequate when given weekly for 6 weeks. Maintenance therapy is important as noted in both of our clinical arms. BCG and interleukin-2 therapy results in a higher remission rate.

BCG Vaccine↗
PubMed1991

Extracorporeal shock-wave lithotripsy in patients with spinal cord dysfunction.

Patients with spinal cord dysfunction are at an increased risk for urolithiasis. A retrospective study was undertaken to determine the effectiveness of extracorporeal shock-wave lithotripsy (ESWL) in this population. Thirteen kidneys received 19 treatments averaging 2,350 shocks per renal unit. All but one of the stones showed good fragmentation; however, none of the patients was stone-free at three months. Four of 9 patients with long-term follow-up were stone-free at five to fifteen months. Our poor stone-free rate is similar to that found in other studies of patients with spinal cord dysfunction. ESWL was well tolerated in this population, however, the clearance of stones is poor and delayed.

Adult↗
PubMed1991

World Health Organization Consensus Committee recommendations concerning the diagnosis of BPH.

The expert committees, which met in Paris in June 1991 under the patronage of WHO to establish a consensus concerning BPH, adopted the recommendations summarised in this report. Despite certain criticisms which can be made, these recommendations offer the advantage of simplicity and uniformity, thereby constituting a "universal language". This will facilitate comparison of patients and therapeutic results, both in everyday practice and in the course of clinical trials. These recommendations will be periodically re-evaluated in the light of clinical experience and technological progress.

Clinical Protocols↗
PubMed1990

Influence of intravesical administration of tumor necrosis factor alpha and systemic gamma-interferon on murine bladder cancer: lack of dose response.

The effect of intravesical administration of high dose recombinant tumor necrosis factor-alpha (rTNF) and in combination with systemic recombinant gamma-interferon (rIFN) on murine bladder cancer was studied. RTNF was given at 12.5 micrograms/mouse on days 7, 11 and 15 after tumor instillation or at 2.5 micrograms/mouse on days 7, 9, 11, 13 and 15. Some groups were also injected i.v., 24-h prior to each rTNF treatment with rIFN at a dose of 1.3 micrograms/mouse. RTNF treatment suppressed tumor growth up to 48% of control, although the difference was not statistically significant. Combined administration of rIFN did not provide additional benefit.

Administration, Intravesical↗
PubMed1990

Clonal growth of bladder cancer cells in a double layer soft agar assay: needles addition of multiple culture supplements.

The necessity of multiple culture supplements, characteristic of Hamburger and Salmon (H&S) soft agar assay (1977), for the clonal growth of bladder cancer cells was systematically investigated. One murine and 6 human cell lines were cultivated in different culture supplemented conditions based on the H&S method. All cell lines successfully formed colonies in the absence of supplements. The inclusion of 2-mercaptoethanol to supplement-free medium stimulated the clonal growth of murine (MBT-2) cells, whereas it did not affect the growth of human cell lines. DEAE-dextran suppressed the clonal growth of 5 out of 7 lines. Tryptic soy broth stimulated the growth of 2 human cell lines, whereas it suppressed the other 2 cell lines. The chemosensitivity of MBT-2 cells was not affected by these supplements.

Animals↗
PubMed1990

Cortisone inhibition of tumor angiogenesis measured by a quantitative colorimetric assay in mice.

A simple and quantitative angiogenesis assay was developed. Using this assay, the angiostatic effect of cortisone acetate (CA) on three murine tumors was studied. Tumor cells were inoculated i.d. into the syngeneic or heterogeneic hosts (day 0) and the degree of angiogenesis was quantitated on day 3 by measuring the tumor vascular volumes using an Evan's blue perfusion technique. CA treatment (250 mg/kg for 3 days) significantly suppressed tumor angiogenesis; however, the degree of angiostatic effect was influenced by the tumor types and by the mouse strain used. MBT-2 bladder cancer angiogenesis was suppressed by 77%-80% of controls in C3H/HeN and C57B1/6 mice, whereas MBT-2 angiogenesis in BALB/c mice was significantly less suppressed by CA (65% inhibition) as compared with values obtained for C3H mice. B16 melanoma or Line-1 lung-cell carcinoma-induced angiogenesis was suppressed by 57%-66% in their syngeneic or heterogeneic hosts. The combined administration of CA and heparin (Sigma; 1,000 units/ml in drinking water) did not influence the outcomes. The data suggest that host factor(s) and tumor factor(s) influenced the expression of CA angiostatic activity. This colorimetric assay enabled a quantitative estimation of the degree of angiogenesis in mammalian animals.

Animals↗
PubMed1990

Influence of high-energy shock waves and cisplatin on antitumor effect in murine bladder cancer.

The potential application of high-energy shock waves (HESW) for control of experimental bladder cancer was investigated. Subcutaneous 3-d murine bladder cancer (MBT-2) in C3H mice were exposed to HESW alone (250 to 1,500 shocks) or in combination with cisplatin (5 to 10 mg/kg, i.p.). Although HESW alone showed no influence on tumor growth, HESW/cisplatin combination therapy suppressed tumor growth more than cisplatin alone. Subsequent studies revealed that an air-fluid interface relative to tumor location played a pivotal role for the chemosensitizing effect of HESW. HESW treatment was able to enhance the cisplatin cytotoxicity only when the tumors were placed adjacent to the air-fluid interface.

Animals↗
PubMed1989

Differential effects of cyclosporin on hepatic and renal heme, cytochrome P-450 and drug metabolism. Possible role in nephrotoxicity of the drug.

Treatment of rats with 25 or 50 mg/kg cyclosporin A for 6 days elicited vastly different responses in hepatic and renal heme and drug metabolism activities. In the liver, cytochrome P-450 concentration was decreased significantly (to 70-75% of the control). This was accompanied by a marked reduction in benzo[a]pyrene hydroxylase activity (to 20-28% of the control). Aniline hydroxylation was also decreased, but to a lesser extent (to 77% of the control). In contrast, in the kidney cytochrome P-450 concentration was significantly increased to (145-170% of the control), along with a modest decrease in benzo[a]pyrene hydroxylation activity. In this organ, the concentration of porphyrins was severely decreased (to 30% of the control). Also, the activities of delta-aminolevulinate (ALA) synthetase and ALA dehydratase, as well as that of heme oxygenase, were inhibited. It is suggested that in the kidney the inhibition of degradation, rather than an enhanced rate of synthesis of the heme molecule, contributes to the observed increase in cytochrome P-450 concentration. In the liver, the decrease in the cytochrome concentration could not be explained in terms of an alteration in the rate of heme biosynthesis or degradation. Therefore, the observed decrease in cytochrome P-450 concentration could reflect the direct inactivation of the hemoprotein or regulation of apoprotein production by cyclosporin and/or its metabolite(s). The possible relevance of the observations to cyclosporin nephrotoxicity is discussed.

Aniline Hydroxylase↗
PubMed1989

Improved use of buthionine sulfoximine to prevent cisplatin nephrotoxicity in rats.

Male Sprague Dawley rats were treated with buthionine sulfoximine (BSO) and cisplatin in different doses and schedules to optimize the chemoprotective effect of BSO against cisplatin nephrotoxicity. BSO at 4 mmol/kg, administered s.c. 2 h prior to cisplatin, resulted in normal blood urea nitrogen (BUN) levels in rats treated with 3 or 4 mg/kg cisplatin, and modestly, but significantly reduced the toxicity of cisplatin at 5 mg/kg. Administration of BSO (4 mmol/kg) at intervals ranging from 0 to 16 h prior to cisplatin (5 mg/kg) resulted in a significant reduction in BUN values. A BSO dose as low as 0.04 mmol/kg was found to be as effective as 4 mmol/kg against nephrotoxicity associated with cisplatin at 4 mg/kg. Repetitive injections of BSO (1 mmol/kg every 12 h, four times, beginning 2 h prior to cisplatin) significantly inhibited elevations of BUN associated with higher-dose cisplatin (6 mg/kg), whereas a single BSO injection of 4 mmol/kg was ineffective. The degree and duration of renal glutathione depletion was related to the dose of BSO. Renal glutathione content following 4 mmol/kg BSO was 38% of control at 2 h and 40% at 24 h; following 0.04 mg/kg, glutathione was 47% at 2 h and almost 100% at 24 h. Simultaneous in vitro administration of BSO did not inactivate cisplatin cytotoxicity as measured by the colony-forming ability of MBT-2 cells in soft agar. These data indicate that repeated injections of BSO, beginning prior to cisplatin administration, would improve the nephroprotective effect without compromising the chemotherapeutic efficacy of cisplatin. It is suggested that the ability of BSO to reduce cisplatin nephrotoxicity may not correlate with the degree of renal glutathione depletion and that the mechanism of action is unlikely to involve direct inactivation of cisplatin.

Animals↗