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M Caine

Publications and source records attributed to M Caine.

At least 37 records · Page 2Linked to original sources
PubMed1986

Clinical experience with alpha-adrenoceptor antagonists in benign prostatic hypertrophy.

The symptomatic treatment of benign prostatic hyperplasia with alpha-adrenoceptor antagonists is based on the concept of a dynamic component in prostatic obstruction, dependent on the sympathetically controlled tone of smooth muscle in the prostate and its capsule. Blockade of the alpha adrenoceptors minimizes this tone, hence the degree of obstruction, and also relieves the irritative symptoms. A review of the published clinical experience reveals convincing evidence of a beneficial action on the irritative symptoms of diurnal and nocturnal frequency, and on the objective parameters of uroflow, residual urine, urethral closure pressure, and cystometrographic evidence of detrusor instability. It is also of value in the prophylaxis or treatment of certain cases of acute retention in these patients. The greatest amount of experience has been with phenoxybenzamine, which appears to be the most effective drug in practice, but other drugs are being assessed for this purpose. It is possible that a combined alpha 1 and alpha 2 antagonist may be more effective than a pure alpha 1 antagonist.

Adrenergic alpha-Antagonists↗
PubMed1986

Comparison of the alpha-adrenoceptor characteristics in human and canine prostate.

Alpha adrenoceptors, mediating contraction, have been shown to be present in strips of hypertrophic prostate surgically removed from patients with benign prostatic hypertrophy (BPH), providing a rational explanation for the demonstrated effectiveness of alpha antagonists in the symptomatic treatment of this disease. Inasmuch as the dog develops spontaneous and hormonally induced prostatic enlargement, studies were performed to compare the adrenoceptor characteristics of canine and human prostate to determine whether the dog represents a useful model to search for more effective alpha-adrenolytic therapy for human BPH. Norepinephrine produces contraction in isolated strips of canine prostate although it is only one-tenth as potent as previously reported in human tissue. In contrast, several selective alpha 1-adrenoceptor agonists are potent contractile agents in canine prostate, but are nearly inactive in the human tissue. This difference may be a consequence of their partial agonist character. The potency of selective alpha-adrenoceptor antagonists in blocking the norepinephrine-induced contractile response in both canine and human tissue is consistent with an action of norepinephrine on the alpha 1 adrenoceptor. The receptor dissociation constants for these antagonists are similar in prostatic tissue from dogs and humans, and the values in canine tissue correlate well with those obtained in the rabbit ear artery, a standard model for vascular alpha 1 adrenoceptors. Hence the dog may represent a useful model for studies of the potential responsiveness of human prostate to adrenergic agents.

Adrenergic alpha-Antagonists↗
PubMed1986

Peripheral factors in urinary continence.

Urinary continence is dependent upon satisfactory bladder relaxation together with adequate closure of the outflow tract. The former is mainly controlled by the interaction of the cholinergic and adrenergic mechanisms, at both central and peripheral levels. In addition, purinergic nerves, Vasoactive Intestinal Peptide (VIP), and prostaglandins may possibly play a role in the regulation of the detrusor tone. The factors responsible for closure of the outflow tract may be grouped into three local and one extrinsic mechanisms. The distal continence mechanism comprises the peri-urethral pelvic floor striated muscles, which are under somatic neural control. Their function is mainly that of active continence, produced by voluntary contraction. The proximal mechanism is that producing closure of the bladder neck, and is the consequence of the tone and arrangement of the smooth muscle fibres in this region. The intrinsic mechanism acts along the length of the female urethra (or posterior urethra in the male) and is dependent upon the functioning of several constituents of the urethral wall. The tone of both the smooth muscle (lissosphincter) and the striated muscle (rhabdosphincter) in the wall produces a centripetal force which acts upon the inner layers of the urethra, compressing them and producing a hermetic seal. These structures, the mucosa and the cushioning vascular channels in the submucosa, are of particular importance in the female, where they are hormone-sensitive. The extrinsic mechanism consists of the transference of intra-abdominal pressure rises via the wall of the intra-pelvic urethra, assisted by a simultaneous reflex contraction of the pelvic floor, so as to supplement the already existing closure pressure at the moment of stress.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1986

Nontraumatic spontaneous rupture of the urinary bladder.

Rupture of the urinary bladder without a history of recent trauma or instrumentation is rare; it is usually associated with bladder disease or outlet obstruction. The patient is usually seen as an emergency case and has an atypical clinical picture. The four patients in this report were initially seen and treated by a general surgeon; in only two was the diagnosis established preoperatively and confirmed by retrograde cystography. Awareness on the part of the consulting surgeon that bladder rupture is possible in a predisposed patient may lead to a correct preoperative diagnosis. In this series, early operation--removing urine from the peritoneal cavity or retropubic space, closing the rupture and securing good vesical drainage--resulted in resumption of vesical function in all four patients and there were no deaths.

Adult↗
PubMed1985

In vitro characterization of the alpha-adrenoceptors in human prostate.

The alpha-adrenoceptors of the human prostate gland were characterized in vitro by the use of antagonists selective for alpha 1- and alpha 2-adrenoceptor subtypes. The contractile response induced by norepinephrine in this tissue could be antagonized by prazosin, a selective alpha 1-antagonist, with a receptor dissociation constant (KB) of 4.0 +/- 0.9 nM. The selective alpha 2-antagonists rauwolscine and SK&F 86466 were less potent antagonists of this response, with KB values of 1020 +/- 400 nM and 2400 +/- 800 nM, respectively. The irreversible alpha-antagonists benextramine and phenoxybenzamine, both of which preferentially inactivate the alpha 1-subtype, produced marked depression of norepinephrine-induced contraction. These data would suggest that the alpha-receptors on prostatic smooth muscle are predominantly of the alpha 1-subtype.

Adrenergic alpha-Antagonists↗
PubMed1985

Diagnosis and management of renal angiomyolipoma.

Renal angiomyolipoma (hamartoma) is an uncommon benign tumor of the kidney. Although about 400 cases of renal angiomyolipoma have been reported, it still causes difficulties in diagnosis and treatment. Until a few years ago it was almost impossible to arrive at a correct diagnosis preoperatively, and most of the cases underwent nephrectomy with the wrong diagnosis of renal carcinoma. More recently, abdominal computerized tomography and renal sonography have made it possible to reach the correct preoperative diagnosis in many cases, and thus to avoid unnecessary nephrectomies. We report on our experience with 13 cases of renal angiomyolipoma, and our conservative approach in a number of cases, which has enabled us to preserve renal tissue and function.

Adolescent↗
PubMed1984

The effect of nicergoline on the lower urinary tract muscle.

Two series of experiments were performed to determine whether nicergoline possesses an alpha-adrenergic blocking action on the lower urinary tract musculature in dogs and humans. One series consisted of in vivo studies of urethral pressure profile recordings in 19 female dogs, and their responses to adrenergic stimulation with noradrenaline or methoxamine, alone and following administration of nicergoline. The other series consisted of in vitro isometric studies of 61 strips of human prostate, and the establishment of dose response curves to nor-adrenaline alone and in the presence of various concentrations of nicergoline. In both sets of experiments clear evidence of an alpha-adrenergic blocking effect was obtained. From the in vitro experiments, the Kb of nicergoline was calculated as less than or equal to 9 X 10(-9) M.

Adenoma↗
PubMed1982

Comparative experimental study on the use of the carbon dioxide laser beam in partial nephrectomy.

A report is given on an experimental study in 20 dogs designed to compare the use of the CO2 laser beam as a cutting instrument in resection of the kidney parenchyma, with the simple scalpel and the cutting diathermy current. It was found that the laser can be used with impunity. It shortens the time of operation by facilitating hemostasis, diminishes blood loss, and does not interfere with the final kidney function. The damage to the kidney parenchyma compares favorably with the produced by the other instruments.

Animals↗
PubMed1982

The clinical use of CO2 laser beam in the surgery of kidney parenchyma.

Encouraged by the experimental work done on 40 kidneys in 20 dogs using the CO2 laser beam for partial nephrectomies, we decided to use the laser in four patients. Three of them underwent lower partial nephrectomy, and the fourth underwent bivalving of kidney through the anatrophic line. The use of this new instrument was very helpful in reducing blood loss, shortening the time of hemostasis, and minimizing parenchymal damage. Case No. 1 is the first published case of xanthogranulomatous pyelonephritis that underwent partial nephrectomy with success.

Adult↗
PubMed1982

Adrenergic response of bladder muscle in prostatic obstruction. Its relation to detrusor instability.

In vitro isometric studies of bladder dome muscle taken at operation from 47 patients with benign prostatic obstruction, revealed an alpha-adrenergic response instead of the normal beta response in 23 per cent. The relationship between this finding and the presence of irritative symptoms and an unstable detrusor is examined. This finding may explain the beneficial effect of alpha-blockers on these symptoms in many patients with prostatic obstruction.

Humans↗