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Biomedical subjects

P T Doyle

Publications and source records attributed to P T Doyle.

At least 19 recordsLinked to original sources
PubMed1997

Surgical management of the renal manifestations of von Hippel-Lindau disease: a review of a United Kingdom case series.

OBJECTIVE: To review the results of nephron-sparing surgery in a group of patients with von Hippel-Lindau (VHL) disease, a rare familial cancer syndrome which is dominantly inherited and predisposes affected individuals to developing various tumours, including haemangioblastomas of the retina and central nervous system, and multicentric renal cell carcinoma (RCC). PATIENTS AND METHODS: The 11 patients (seven men and four women, age range 27-62 years) assessed had been referred for surveillance to the Department of Clinical Genetics, Addenbrooke's Hospital, often having presented with neurological or ocular manifestations of the disease. Their case notes were reviewed to assess the results of conservative surgery. Five patients had more than one parenchymal-sparing operation (either partial nephrectomy or enucleation, i.e. removal of a malignant lesion with a 0.5 cm rim of normal tissue) while four had bilateral procedures. At the time of surgery, co-existent cysts were aspirated to allow a more accurate definition on computed tomography during follow-up. RESULTS: At a mean follow-up of 60 months after surgery, eight patients were alive with good renal function. Three patients were alive with paraplegia or paraparesis from spinal cord lesions. The three patients who died (aged 50, 40 and 31 years) were diagnosed when RCC was already advanced and renal tissue-preserving surgery was not possible. CONCLUSIONS: Nephron-sparing surgery may be justified because morbidity is reduced in patients whose quality of life may already be compromised by neurological and other problems, and because the lesions of RCC are often small, enucleation may also be justifiable in the attempt to conserve renal tissue and delay disease progression.

Adult↗
PubMed1996

A review of antegrade stenting in the management of the obstructed kidney.

OBJECTIVE: To review experience in the management of the obstructed ureter using antegrade stenting in a variety of conditions. PATIENTS AND METHODS: Between 1984 and 1993, 41 patients (mean age 57 years, range 9-83) had antegrade stents placed by an experienced interventional radiologist. The causes of obstruction were urological in 27, gynaecological in eight, colorectal in three and miscellaneous in three. RESULTS: The overall success rate for antegrade stent insertion was 83% and the failure rate was greatest (four of six) in cases of ureteric injury following gynaecological procedures. There were no immediate complications. CONCLUSION: Antegrade stenting can be used as a temporary or permanent solution to ureteric obstruction. The technique is safe, acceptable to patients and avoids the need for a general anaesthetic.

Adolescent↗
PubMed1994

Inhibition in the human urinary bladder by gamma-amino-butyric acid.

OBJECTIVE: To investigate the effects of gamma-amino-butyric acid (GABA) on detrusor activity in man to determine whether it has any inhibitory effect on detrusor contraction. The inhibitory neurotransmitter GABA has been found in mammalian urinary bladders and the effects of GABA on detrusor activity in the rabbit bladder has previously been described [1]. MATERIALS AND METHODS: Human detrusor muscle strips, obtained at cystectomy, were made to contract by electrical stimulation of their autonomic nerves or by the addition of carbachol in a superfusion apparatus. GABA and its analogues were added to the superfusion chamber and any changes in the responses were measured. RESULTS: The electrically evoked nerve-mediated contractions in human bladder muscle were exclusively cholinergic. GABA inhibited nerve-mediated contractions in human detrusor muscle-strips by the activation of the GABAB receptor, since baclofen (a GABAB receptor agonist) produced similar inhibition and muscimol (a GABAA receptor agonist) did not. There was no inhibition of carbachol-mediated contractions by GABA. CONCLUSION: This in vitro study shows that GABA has a peripherally mediated inhibitory effect on excitatory neurotransmission in human detrusor muscle. The site of action is on the post-ganglionic nerves and appears to be mediated via the GABAB receptor.

Aged↗
PubMed1993

Data collection and complication rates in clinical audit.

Audit data were collected continuously between February 1988 and July 1991. For the initial period (February 1988-June 1990) data were collected by monitoring of ward admission and discharge records and by collecting data from operating theatre records whilst complications were noted in a 'complications book' which was kept on the notes trolley. In July 1991, when a computerized system for storing and processing audit data was introduced into the department, the methods of data collection changed. For each patient a proforma was attached to the clinical notes which was filled in at each stage of the hospital stay. On this proforma was a list of possible complications which were ticked, as appropriate, at the time of discharge from hospital. We have reviewed the results of clinical audit during these two periods. The number of operations performed per month fell slightly in the latter period (p = 0.005). However, there was a significant increase in both the number of complications (p < 0.0001) and in the complication rate (p < 0.0001). Further analysis showed that there was a similar increase in the number of recorded major and minor complications, and that this increase was also seen even when changes in medical personnel were accounted for. We suggest that the increased complication rate recorded in the latter period reflects the change in the method of data collection. This has important implications when comparing outcome measures for clinical departments.

Consultants↗
PubMed1992

Inhibitory role of gamma-amino-butyric acid in the rabbit urinary bladder.

Gamma-amino-butyric acid (GABA) is an established inhibitory neurotransmitter in the central nervous system (CNS) and it has also been identified in the bladder. We have investigated in the rabbit the effect of GABA on detrusor activity. Rabbit detrusor muscle strips were made to contract by electrical stimulation of their autonomic nerves or by the addition of carbachol. The addition of GABA caused substantial inhibition of muscle contraction. GABA acts on 2 classes of receptors-GABAA and GABAB. The inhibition was mediated via the GABAB receptors as its effect was mimicked by baclofen (a GABAB agonist) and inhibited by 2-hydroxysaclofen (a GABAB receptor antagonist). Inhibition was not prevented by bicuculline (a GABAA receptor antagonist). This inhibition may be due to a direct muscle effect since the inhibition, which occurred with carbachol-induced contraction, was not abolished by the addition of tetrodotoxin. GABA, acting via the GABAB receptor, produces substantial inhibition of muscle contraction in the rabbit urinary bladder. This raises the possibility of using GABAB analogues in the treatment of detrusor instability.

Animals↗
PubMed1992

Rectal obstruction secondary to carcinoma of the prostate treated by transanal resection of the prostate.

Rectal obstruction caused by carcinoma of the prostate is uncommon. If the disease does not respond to either hormonal treatment or radiotherapy, the only surgical means of relieving the obstruction has been the formation of a colostomy. We present an alternative treatment, since many of these patients are elderly with a short life expectancy and they may have difficulty coping with a stoma. Seven transanal endoscopic resections of the prostate (TARP) have been performed on 5 patients. The procedure is not without complications, but it does offer simple surgical palliation of the rectal obstruction and obviates the need for a colostomy.

Aged↗
PubMed1990

Computed tomography and magnetic resonance imaging before salvage cystectomy.

Nine patients who developed recurrence of bladder carcinoma following radical radiotherapy were assessed for salvage cystectomy by computed tomography (CT) and magnetic resonance imaging (MRI) to predict extravesical spread. Both tests correctly identified a patient with such advanced local disease that surgery was deemed inappropriate at examination under anaesthesia and both tests indicated that surgery might be difficult in a further patient with inoperable disease. Both tests demonstrated abnormalities in the perivesical and pelvic fat planes in all patients but they had difficulty in distinguishing between malignant infiltration and the effects of radiotherapy. Nevertheless, each test is useful in excluding gross pelvic disease and predicting involvement of adjacent organs. The advantages of the multiplanar images provided by MRI must be balanced against the high cost. CT readily demonstrates the upper abdomen, the kidneys and para-aortic nodes as well as the pelvis and is more widely available.

Aged↗
PubMed1990

Identifiable factors in post-prostatectomy haemorrhage: the role of aspirin.

Post-operative haemorrhagic complications following the ingestion of aspirin have been reported after several types of surgery, most notably coronary artery bypass surgery. In this study, aspirin ingestion also appeared to be a significant aetiological factor in post-prostatectomy haemorrhage. This is explained in terms of its inhibitory effect on platelet aggregation. A history of aspirin ingestion should be carefully sought and its haemorrhagic implications considered prior to prostatectomy.

Aged↗
PubMed1990

Effect of bladder outflow obstruction on the innervation of the rabbit urinary bladder.

The effects of bladder outflow obstruction on the innervation of the bladder were studied using a rabbit animal model. Partial occlusion of the bladder neck was obtained by the placement of a silk ligature at that level; control animals underwent a sham procedure. After a 3-month period, the presence of outflow tract obstruction was confirmed using urodynamic studies. The animals were then killed and pharmacological assessments of the bladder innervation undertaken. Detrusor muscle strip studies provided evidence of damage to the cholinergic innervation of the detrusor. Also, muscle strips from obstructed animals showed reduced inhibitory responses to beta-adrenergic stimulation with isoprenaline. In addition to these muscle strip studies, the bladder content of the neuropeptide substance P was assayed, but no significant change was observed in response to obstruction. This finding suggests that substance P-containing sensory nerves may be spared from the denervating effect of bladder outflow obstruction.

Animals↗
PubMed1988

The investigation of painless haematuria--a comparison of intravenous urography and DMSA scintigraphy.

In order to test in a prospective study the suggestion that there should be a shift from the intravenous urogram to DMSA scintigraphy for the diagnosis of suspected renal masses, both investigations were performed in 63 patients with painless haematuria. While the sensitivity of both investigations was similar in renal lesions, specificity was slightly less for scintigraphy. These findings, together with the intrinsic limitations of the DMSA scintigram in detecting lesions elsewhere in the urinary tract, lead us to conclude that the intravenous urogram should remain the initial investigation for painless haematuria unless there are specific contraindications.

Hematuria↗