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Biomedical subjects

P H Powell

Publications and source records attributed to P H Powell.

18 recordsLinked to original sources
PubMed1991

The role of colour duplex ultrasonography in the diagnosis of vasculogenic impotence.

Colour duplex ultrasonography was used to obtain peak systolic velocity (PSV) readings from cavernosal arteries at rest and during papaverine-induced tumescence. Results from 31 men with vasculogenic impotence were compared with those from 17 men with non-vasculogenic impotence and a control group of 6 potent men. In the flaccid state no significant differences in PSV readings were found between the vasculogenic and control groups. Following the injection of papaverine, men from the vasculogenic group without venous leakage were alone in having significantly lower PSV readings compared with the potent controls. All 23 men with normal penile haemodynamics had a mean PSV greater than or equal to 20 cm/s during tumescence. This was also the case for 19 (61%) of the vasculogenic group, including 9 (69%) of the 13 patients with venous leakage. The remaining 12 men in the vasculogenic group (39%) had a mean PSV less than 20 cm/s, this being diagnostic of an inadequate arterial inflow. Colour duplex ultrasonography can identify patients who have marked arterial insufficiency as the major cause of their impotence and hence allows more rational selection for angiography and revascularisation. Lesser degrees of arterial deficit are difficult to characterise using mean PSV readings alone.

Adult↗
PubMed1991

The effect of inhibitors of nitric oxide biosynthesis and cyclic GMP formation on nerve-evoked relaxation of human cavernosal smooth muscle.

1. The inhibitory transmission in isolated preparations of cavernosal smooth muscle from human penis has been studied. 2. Electrical field stimulation (EFS; 2-64 pulses/train, 0.8 ms pulse duration, 10 Hz) evoked relaxation of preparations treated with guanethidine (50 microM). The EFS-evoked relaxations were atropine-resistant and tetrodotoxin-sensitive indicating their origin to be non-adrenergic, non-cholinergic (NANC) nerve stimulation. 3. EFS-evoked relaxation was attenuated dose-dependently by the nitric oxide (NO)-synthase inhibitor, L-NG-nitro arginine (L-NOARG; 0.3-100 microM) but not by D-NG-nitro arginine. The inhibitory effect of L-NOARG on transmission was antagonized by L-arginine (100 microM), a NO precursor, but not by D-arginine. 4. Incubation with methylene blue (10-50 microM), a known inhibitor of guanylate cyclase activation by NO, caused a concentration-related inhibition of EFS-evoked relaxation. 5. It is concluded that NANC nerve-evoked relaxation of human cavernosal smooth muscle is mediated by NO or a NO-like substance.

Arginine↗
PubMed1989

Outcome of elective prostatectomy.

OBJECTIVES: To determine the symptomatic and urodynamic outcome of elective prostatectomy and to establish whether the outcome is influenced or can be predicted by preoperative urodynamic measurements. DESIGN: Prospective non-randomised study with follow up at a mean of 11 months after operation. Most men were assessed jointly by a urologist and a general practitioner. SETTING: Department of urology in a teaching hospital serving a large district population. PATIENTS: 253 Men listed for elective prostatectomy because of symptoms and low urinary flow rates (less than 15 ml/s) and excluding those already on a waiting list or with acute urinary retention, clinically apparent prostatic cancer, and neurological or cerebrovascular disease; 217 (86%) were followed up. INTERVENTION: Elective prostatectomy. MAIN OUTCOME MEASURE: Classification on the basis of relief of symptoms assessed by patients and urologist and general practitioner and of symptom scores obtained by questionnaire. RESULTS: Of the 217 men followed up, 171 (79%) had a satisfactory subjective review and 155 (72%) had a satisfactory review and also low symptom scores. An unsatisfactory outcome was associated with preoperative symptoms of urge incontinence, small prostatic size and resected weight, low voiding pressures, and low urethral resistance. Preoperative maximum urinary flow rates did not predict outcome. Men with poor outcome could be classified into two groups: those with irritative symptoms who were more likely before operation to have had urge incontinence and detrusor instability and men with symptoms of poor urinary flow who were more likely before operation to have had a small prostate, low voiding pressures, and low urethral resistance. In patients in the second group flow rates or voiding pressures improved little after operation. Men with stable detrusors and either low urethral resistance or low voiding pressures were less likely to do well after prostatectomy, but despite these associations preoperative urodynamic measurements were unable to predict outcome accurately. CONCLUSIONS: Prostatectomy was satisfactory in relieving symptoms and improving urodynamic measurements in most men, but even in those with classic symptoms and low urinary flow rates a substantial minority experienced little improvement afterwards and urodynamic measurements did not accurately predict outcome in individual patients.

Follow-Up Studies↗
PubMed1988

Deferred treatment for prostate cancer.

The clinical outcome of 278 prostate cancer patients managed by a deferred treatment policy was analysed retrospectively. Following TURP or biopsy, all patients were asymptomatic and deemed suitable for management by a deferred treatment policy, i.e. hormone therapy or other forms of treatment were only initiated if and when symptomatic progression occurred. The overall 5-year survival rate was 30%; 18% of patients died from other causes without needing treatment for their prostate cancer; 11% were alive and untreated after 5 years' follow-up; 17% died from prostate cancer without further treatment. Poor tumour grade, anaemia, metastatic disease, a short history, presentation with retention, and a raised serum creatinine at presentation were associated with a poor prognosis.

Aged↗
PubMed1988

Reproducibility of measurement of prostatic volume by ultrasound. Comparison of transrectal and transabdominal methods.

88 men undergoing elective prostatectomy were investigated by transrectal and transabdominal ultrasound. A repeat examination was performed by a second observer in 28 patients. The aims were to determine the correlation between transrectal and transabdominal ultrasonic estimation of prostatic volume and the degree of observer error. Transabdominal estimation of prostatic volume correlated well with the transrectal method (p less than 0.001) and good agreement between the two observers was found with both methods (p less than 0.001). In the individual patient, however, a wide variation in prostatic volume was found between the two observers and the two methods.

Aged↗
PubMed1987

Detection of blood group antigens in frozen sections of prostatic epithelium.

The detection of blood group antigens (BGA) in non-malignant prostates by previous workers has been at best inconsistent. BGA have not before been detected in prostatic carcinomas. In this preliminary study, a variety of anti-BGA reagents, with known specificities that involve the carbohydrate backbone in addition to the BGA specific terminal monosaccharides, were used to study the expression of the A and H (O) BGA in cryostat sections of 16 patients with benign prostatic disease and nine with prostatic cancer. Positive staining, appropriate to the patients' blood group, was seen in all of the benign tissues when anti-BGA reagents that included specificity against type 2 backbone structures were used. Staining was absent, however, if the reagent had only type 1 specificity. The anti-A and anti-H (O) reagents which gave the best staining patterns in benign tissues were used in malignant tissues. No cancer was found to express A antigen but eight of the nine prostatic cancers were positive for the H (O) antigen irrespective of blood group. Using fresh frozen material and appropriate reagents, BGA may be reproducibly detected in the epithelium of all non-malignant prostates, suggesting that a significant component of BGA is probably lipid-based on type 2 carbohydrate backbone chains. Further studies of changes in BGA expression in prostatic cancer are warranted.

ABO Blood-Group System↗
PubMed1987

Relationship between voiding pressures, symptoms and urodynamic findings in 253 men undergoing prostatectomy.

Two hundred and fifty-three men (age 69.2 +/- 7 years) undergoing prostatectomy for bladder outflow obstruction were studied. The aims were to determine the distribution of voiding pressures and their relationship to presenting symptoms and urodynamic findings. Symptoms were scored by means of a standardised questionnaire and urodynamic studies were performed. Within this study group, high obstructive symptom scores were associated with low flow rates and high urethral resistance. However, high voiding pressures were not associated statistically with low flow rates or obstructive symptoms. Voiding pressures followed a unimodal, parametric distribution and a significant number of men had voiding pressures within the normal range: 9.1% had voiding pressures less than 55 cm H2O and 27.7% less than 75 cm H2O. Irritative symptoms, on the other hand, correlated significantly with obstructive symptoms, high voiding pressures and urethral resistance. Furthermore, high voiding pressures were associated with small cystometric bladder capacities, low compliance and detrusor instability. Whilst these clinical and urodynamic parameters were associated statistically with voiding pressures, none proved specific in being able to identify men with voiding pressures in the high or low end of the range.

Aged↗
PubMed1987

Relationship between detrusor function and residual urine in men undergoing prostatectomy.

Two hundred and fifty-three men undergoing prostatectomy were studied by means of urodynamic investigation to determine the relationship between the volume of residual urine and detrusor function. Increased volumes of residual urine were associated significantly with increasing age, low peak flow rate and high urethral resistance. However, weak voiding pressures were uncommon and did not correlate with increased residual volumes. Increased residual volumes also correlated significantly with a high resting detrusor pressure and a high detrusor pressure rise during the filling phase, but there was a wide scatter of the results for pressure rise and patients could not be classified into groups on the basis of this parameter. Whilst detrusor decompensation was not manifest by weak voiding pressures in patients with increased residual volumes, impairment of the ability of the detrusor to empty the infused cystometric capacity during the subsequent voiding study correlated with increased residual volumes. These data are consistent with theories relating bladder outflow obstruction to the development of increased volumes of residual urine in men undergoing prostatectomy.

Aged↗
PubMed1986

Immunological and colorimetric determination of prostatic acid phosphatase--technical and clinical reappraisal in symptomatic patients.

We compared a selection of quantitative immunological methods for prostatic acid phosphatase (PAP) with routine colorimetric assays for total and tartrate-labile acid phosphatase and evaluated their relative clinical merits in the differential diagnosis of prostatic carcinoma. We also assessed a wide range of commercial control materials for suitability of use with these methods. Patients studied included 111 cases of prostatic carcinoma, 42 cases of benign prostatic hyperplasia, and 33 controls. The principles of the methods used included determination of enzymatic activity using p-nitrophenyl phosphate, RIA, immunoradiometric, and enzymoimmunometric assays. Performance characteristics for the immunological methods were inferior to manufacturers' precision and specificity claims. We identified control materials that were unsuitable for routine use. Poor discrimination between clinical groups was observed for all methods. Analysis by use of a receiver operator characteristic plot failed to improve this. We conclude that the immunological methods we studied offer no advantages over colorimetric methods in the differential diagnosis of prostatic cancer in symptomatic patients.

Acid Phosphatase↗
PubMed1979

Exploration of the common bile duct: a comparative study.

The results of a retrospective comparative study of 122 patients who underwent explorations of the common bile duct in a district general hospital over a 5-year period are presented. Seventy-eight patients had a supraduodenal choledochotomy, 32 had a transduodenal spincterotomy and 12 had a combination of both procedures. Particular attention was paid to postoperative complications in relation to the grade of the surgeon performing the operation and also to the age of the patient. A total of 78 (64 per cent) patients had definite stones in the common bile duct. Of these patients, 7 (9 per cent) were subsequently shown to have retained stones, all having been operated on by registrars. Registrars also did more negative explorations than consultants. Nine patients (7.4 per cent) died, all but 1 of them being over the age of 70 and 4 of them having had a combined procedure. We conclude that transduodenal exploration should be avoided in patients over 70, particularly when added to a supraduodenal exploration.

Adult↗
PubMed1979

Urinary incontinence: prevalence and needs.

The prevalence of recognised urinary incontinence in a community was found to be 1%; the prevalence of unrecognised incontinence was 3.3% in men and 8% in women in a group practice of 7000 patients. The approach to investigation and management of urinary incontinence in a urodynamic unit and the staffing of this unit are described.

Adolescent↗