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Biomedical subjects

A Ballaro

Publications and source records attributed to A Ballaro.

10 recordsLinked to original sources
PubMed2003

Electromyographic detection of purinergic activity in Guinea pig detrusor smooth muscle.

PURPOSE: We recorded nerve mediated extracellular electrical activity from guinea pig detrusor smooth muscle strips using suction electrodes and determined the electrophysiological origins of this signal and its relationship to contractile activity. MATERIALS AND METHODS: Mucosa-free detrusor strips were prepared from male guinea pigs sacrificed under Home Office license, physiologically superfused, attached to a pressure transducer and electrically stimulated (0.1 millisecond pulses). Electrical signals recorded using a bipolar reversible suction electrode were processed and recorded simultaneously with changes in strip tension. The effect of superfusion with alpha, beta-methylene adenosine triphosphate (ATP), atropine, extracellular [CaCl(2)] depletion and pharmacological Ca2+ channel blockade on the electrical and mechanical signals was determined. RESULTS: A biphasic electrical signal was consistently recorded from 37 detrusor strips. The signal was sensitive to graded reduction in [CaCl(2)] of the superfusate and abolished by tetrodotoxin in 7 preparations. The signal was also abolished in 12 preparations by alpha, beta-methylene ATP in association with an attenuated contraction but not significantly reduced in amplitude (p = 0.77) despite a significant reduction in tension with atropine (mean plus or minus SD 74% +/- 14% of control, p <0.001). The signal was attenuated to a mean maximum of 9% +/- 3% of control by pharmacological Ca2+ channel blockade and the remaining signal was abolished by alpha, beta-methylene ATP. CONCLUSIONS: The extracellular electrical signal recorded from guinea pig detrusor strips using suction electrodes originates from a purinergic mechanism. Although an atropine sensitive component may be present, the signal does not depend on cholinergic neuromuscular transmission and would not be expected to be generated by normal human detrusor. Provided that the electrophysiological basis of purinergic neurotransmission in guinea pig and human bladders is similar suction electrodes may be a valuable tool with which to evaluate in vitro and clinically by electromyography the pathological purinergic neuromuscular transmission that can be expressed in addition to normal cholinergic mechanisms in detrusor from dysfunctional human bladders.

Adenosine Triphosphate↗
PubMed2001

Penile resurfacing for extensive genital warts.

Complete surgical excision followed by reconstruction, of diseased penile skin may result in sexual dysfunction due to tethering of the underlying Buck's fascia by the graft. We describe penile resurfacing for extensive condyloma accuminata, a novel technique that circumvents this complication without compromising clearance of this particular lesion.

Aged↗
PubMed2001

A new approach to recording the electromyographic activity of detrusor smooth muscle.

PURPOSE: Extracellular recordings from the whole intact mammalian bladder of the electrical events leading to contraction of the organ have been elusive for almost 50 years despite the widespread potential applications of such a technique. The principal problem is the need to isolate the small real signals reflecting membrane depolarization from the large electromechanical artifact generated as the organ contracts. In this preliminary study we determined whether electrical signals may be isolated and verified as biological using extracellular bipolar reversible suction electrodes. MATERIALS AND METHODS: Six whole excised guinea pig bladders were mounted in an especially constructed organ bath. Electrical activity resulting from nerve stimulation of the organ was recorded using a novel 10 bipolar Pt/PtCl suction electrode simultaneously with changes in intravesical pressure. Mechanical and pharmacological control experiments were performed to determine the true origin of these signals. RESULTS: A predominantly biphasic electrical signal of a mean amplitude plus or minus standard deviation of 647 plus or minus 301 microV. and a mean duration of 293 plus or minus 51 milliseconds was consistently recorded from the serosal surface of all guinea pig bladders. In all cases the electrical signal and mechanical response to stimulation were completely abolished by 1 microM. tetrodotoxin. The signal always preceded any change in intravesical pressure. It was sensitive to changes in the CaCl2 concentration of the superfusate, abolished by purinergic but not cholinergic neuromuscular blockade and independent of electromechanical artifact. CONCLUSIONS: In this preliminary report we describe a novel technique by which nerve mediated detrusor electrical activity leading to contraction of the whole intact guinea pig bladder may be isolated from artifact and verified as real. We hope that development of this technique may enable its application to the in situ human bladder. However, to our knowledge whether electromyographic activity may be recorded from human detrusor remains to be determined.

Animals↗
PubMed2000

Do we do what they say we do? coding errors in urology.

OBJECTIVE: To determine the accuracy of routine data coding in a large multispeciality urological unit. Materials and methods From the clinical records, the diagnosis and procedure codes were ascribed to 106 finished consultant episodes (FCEs) in urology, by two urological trainees. The codes were compared with those ascribed by professional hospital coders (and of which the trainees were unaware) from information written on the audit form by junior medical staff. Where there were discrepancies in codes an error was recorded and the stage in the coding process in which it occurred was determined. RESULTS: Forty-eight coding errors were found in 38 of the 106 (36%) FCEs; 34 (71%) were caused by inaccurate coding and 14 (29%) were the result of the incorrect completion of audit forms. CONCLUSION: The clinical codes generated from the authors' department do not accurately reflect the clinical practice. If coding errors of this magnitude are typical of urology units in general, the concept of hospital performance tables (which will be generated using routine clinical data) is untenable unless data recording is given higher priority.

Forms and Records Control↗
PubMed1999

Prosthesis implantation after radial free flap phalloplasty in patients with bladder exstrophy.

METHODS: Inflatable penile prosthesis were implanted into sensate radial free-flap phalloplasties in two adult patients with bladder exstrophy. RESULTS: Neither patient reported loss of sensation, and both were able to inflate the prosthesis and engage in sexual intercourse three months later. CONCLUSION: The construction of a functional neophallus is well described however has not previously been reported in exstrophy patients who are suited to this procedure due to the presence of crura, and the absence of a neourethra. Scarring from previous reconstructive procedures however may make implantation difficult, and long-term follow up is required to evaluate this procedure in patients with bladder exstrophy.

Adult↗
PubMed1999

A computer generated interactive transurethral prostatic resection simulator.

PURPOSE: We developed a computer generated model of the prostate gland and an interactive simulator for use in training urologists in transurethral resection of the prostate. MATERIALS AND METHODS: Software was developed on a standard personal computer which allowed images of the lumen of the prostatic urethra and resectoscope loop to be generated and interacted with using a magnetic position sensor input device attached to a dummy resectoscope. RESULTS: An anatomically accurate computer model of the prostate was generated at low cost which permitted user interaction and which simulated key elements of transurethral prostatic resection. CONCLUSIONS: Although not a substitute for learning transurethral prostatic resection on patients, the simulator enabled the user to become familiar with the technique of transurethral prostatic resection in the absence of time constraints and without risk to patients. The simulator may become an important tool in training and assessing surgeon competency, and may reduce the costs of training. Further development is needed to refine the transurethral prostatic resection simulator and expand its surgical range.

Computer Simulation↗
PubMed1998

A seasonal variation in the incidence of ruptured abdominal aortic aneurysms.

OBJECTIVE: To discover whether there is a seasonal variation in the incidence of rupture of abdominal aortic aneurysms. DESIGN: Deaths per month due to rupture of abdominal aortic aneurysm were analysed retrospectively using a cosinor regression model. SETTING: England and Wales. SUBJECTS: 19,599 patients who died from rupture of abdominal aortic aneurysm between January 1991 and December 1995 according to death certification data. INTERVENTIONS: None. RESULTS: A seasonal variation in the incidence of rupture of abdominal aortic aneurysm occurs, with a peak in winter (p = 0.003). The ratio of rupture of abdominal aortic aneurysm in males and females decreased from more than 12 to 1 below age 60 years to less than 5 to 1 over age 80 years. CONCLUSIONS: There is a seasonal variation in the incidence of recorded deaths from abdominal aortic aneurysm in England and Wales, with a peak of deaths in the cold winter months. The underlying cause is unknown, but hypertension and tobacco smoking are predisposing factors to aortic aneurysm rupture. Exposure to tobacco smoke is known to be greater indoors in cold weather and there is a winter peak of blood pressure in hypertensive patients.

Age Factors↗
PubMed1997

Acute colonic pseudo-obstruction after total hip replacement.

Acute colonic pseudo-obstruction is a poorly recognised and potentially fatal complication of hip surgery. Between 1991 and 1994 six patients were observed who required laparotomy after failure of medical management. In three the indication was signs of peritonism, while in the other three exploration was required to exclude segmental ischaemia and to decompress the bowel. In all, there was no evidence of mechanical obstruction. Patients having total hip replacement are at risk of developing pseudo-obstruction due to their age, comorbidity, high doses of analgesics and the nature of the operation. If postoperative ileus persists for more than 48 hours acute colonic pseudo-obstruction should be suspected and confirmed by plain radiography. Prompt recognition and treatment with early referral to a colorectal unit are indicated. Laparotomy appears to carry less risk than that for patients with idiopathic pseudo-obstruction, but should be performed only if colonic ischaemia is suspected.

Acute Disease↗