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Biomedical subjects

A Mattiasson

Publications and source records attributed to A Mattiasson.

100 records · Page 6Linked to original sources
PubMed1984

Influence of antimuscarinics on alpha-adrenoceptors in the female rabbit urethra.

The effects of the tertiary amine atropine and its structural analogues homatropine and scopolamine, as well as the quarternary amine emeprone, were evaluated on noradrenaline (NA)-induced contractions of isolated female rabbit urethral ring preparations. In addition, the abilities of these antimuscarinics to inhibit 3H-dihydro-alpha-ergocryptine (3H-DHE) binding to alpha-adrenoceptors were studied on a crude membrane preparation from the female rabbit bladder base and urethra. Atropine and homatropine depressed the NA-induced contractions in a concentration-dependent way, whereas this was not seen with scopolamine. Emeprone 10(-5) and 10(-4) M augmented the contractions, an effect possibly attributable to a NA-uptake blocking effect. All antimuscarinics displaced specific 3H-DHE binding, the order of potency being atropine greater than homatropine greater than emeprone greater than scopolamine. In general a good correlation was seen between the binding and mechanical activity studies for atropine, homatropine and scopolamine, while this was not found for emeprone. It is concluded that alpha-adrenoceptor blockade by atropine can be observed at concentrations exceeding 10(-7) M. Scopolamine, showing alpha-adrenoceptor blocking properties only in high concentrations, may be used as an alternative for blockade of muscarinic cholinoceptors.

Adrenergic alpha-Antagonists↗
PubMed1984

Acute effects of full urinary bladder and full caecal urinary reservoir on regional renal function. A study with scintillation camera renography.

Scintillation camera renograms were recorded in six patients without a history of bladder function disturbances and in eight patients with caecal urinary reservoir. Each patient was studied once with empty bladder/reservoir and once with full bladder/reservoir. Renograms were obtained from parenchyma, pelvis and whole kidney. Time was measured from injection of isotope to peak of the renogram curve (Tmax) and to the point corresponding to the centre of gravity of the area under the curve (Tg). A full reservoir gave longer Tmax and Tg for both parenchyma and pelvis than an empty reservoir. With full bladder the only significant change was Tg increase for renal pelvis. In the patients with full caecal reservoir, the elimination of radioisotope from the renal pelvis was significantly slower, reflected as longer Tmax and Tg, than in the subjects with full bladder. In comparisons between empty and full bladder/reservoir, Tg permitted clearer separation between the groups than did Tmax. The higher Tmax and Tg values for full than for empty reservoir indicated obstruction to urinary flow and could be ascribed to the high intrareservoir pressure. Regularly occurring pressure waves with amplitudes of 30-65 cm H2O were recorded in the reservoirs, sometimes reflected as transient increases in radioisotope activity in the renograms. In some patients the two kidneys differed considerably in their response to a full urinary bladder or reservoir. The cause may have been difference in the dynamics of the two ureterovesical junctions or of the ureterointestinal anastomoses.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Effects of estradiol on norepinephrine-induced contraction, alpha adrenoceptor number and norepinephrine content in the female rabbit urethra.

Several studies have revealed that estrogen treatment increases the reactivity to catecholamines of various tissues. In the present study it was found that estrogen treatment caused an increased sensitivity to norepinephrine (NE) of the isolated female rabbit urethra. There was a 3-fold shift to the left of the concentration-response curve for longitudinal tension in perfused urethras and for tension in urethral ring preparations. Possible mechanisms for this increase in sensitivity were investigated by studying radioligand binding to the alpha adrenoceptors and by measuring the NE content of the urethras. Using [3H]dihydro-alpha-ergocryptine as a marker for alpha adrenoceptors, a more than 2-fold increase in the receptor number was found after estrogen treatment. This is suggested to be attributable to a selective increase in the number of alpha-2 adrenoceptors. No significant change was found in the affinity of [3H]dihydro-alpha-ergocryptine to the receptor. The total NE content in the urethra was not changed by estrogen treatment. However, if calculated per milligram of wet weight, the NE content was reduced to half in estrogen treated animals. It is suggested that in the rabbit urethra the estrogen-induced increased sensitivity to the contractant effects of NE, at least in part, is attributable to an increase in the number of postjunctional alpha-2 adrenoceptors.

Animals↗
PubMed1983

Electrically induced relaxation of the noradrenaline contracted isolated urethra from rabbit and man.

Isolated urethral preparations from rabbit and man responded to transmural electrical stimulation with contraction when the basal tension was low, and with relaxation when the preparations were contracted by noradrenaline, clonidine, 5-hydroxytryptamine and lysine vasopressin. Both contractant and relaxant responses were abolished by tetrodotoxin, suggesting that they were caused by the action of transmitters released from nerves. The electrically induced contractions in the rabbit urethra had a threshold frequency of 5 to 6 Hz and maximum was reached at 40 Hz. The responses were markedly reduced by alpha-receptor blockers suggesting that the released contraction-mediating transmitter was mainly noradrenaline. The relaxant response was immediate and rapidly reversible. It was obtained at a threshold frequency of 1 to 2 Hz and maximum was reached at 10 to 15 Hz. It was not inhibited by propranolol, indomethacin, atropine or peptides such as substance P, VIP, vasopressin or somatostatin. Prostaglandin E2, isoprenaline, adenosine-5'-triphosphate and VIP relaxed the noradrenaline contracted rabbit urethra with a time course different from that of the electrically induced relaxation. Nifedipine and "calcium free" solution decreased the noradrenaline induced contraction but did not influence the relaxant response to electrical stimulation. It is suggested that the relaxant response of the isolated noradrenaline-contracted urethra to electrical stimulation is caused by an unknown transmitter released from nerves.

Animals↗
PubMed1982

Changes in contractile properties in hypertrophic rat urinary bladder.

Hypertrophy was induced in female rat urinary bladders by partial obstruction of the urethra. After 6 weeks the bladder weight had increased almost 7-fold compared to the matched controls. At this stage the animals were anesthetized and the pelvic nerves stimulated bilaterally at different bladder volumes. Isovolumetric pressures were measured by means of a catheter inserted via the urethra. For control (C) bladders maximum active pressure (104 +/- 11 cm. H2O, n = 5) was attained with 0.10 ml. content. For volumes above this a rapid progressive decrease in active pressure was noted. For hypertrophic (H) bladders maximum active pressure (92 +/- 14 cm. H2O, n = 6) was reached at 0.50 ml. Further filling decreased active pressure only slightly. By use of the law of Laplace the volume-active pressure relations were transformed to radius-force curves. The maximum active stress was similar for C and H bladders. The radius-force relation for H bladders was shifted to the right compared to the C curve (optimum radius for active force: C: 0.4 cm., H: greater than 0.9 cm.). This shift, responsible for the decreased ability to pressure production of the H bladders at small volumes indicates a dramatic remodelling of the smooth muscle in the hypertrophic bladder wall.

Animals↗
PubMed1982

Atropine resistance of transmurally stimulated isolated human bladder muscle.

Human detrusor strips were obtained from patients undergoing reimplantation of ureters because of reflux, transvesical prostatectomy, or cysto-urethrectomy en bloc because of bladder malignancy. The strips were electrically stimulated. A frequency-dependent contractant response was obtained that was potentiated by physostigmine and abolished by tetrodotoxin. The maximum response approximately equaled that of acetylcholine in a maximum concentration. In most bladder preparations from patients without known functional bladder disturbances, atropine (0.01 to 0.1 microM) had a marked inhibitory effect, and at concentrations exceeding 1 microM the blockade was complete. In strips obtained from patients undergoing transvesical prostatectomy, and who also had a cystometrically verified unstable bladder, there was a varying degree of atropine resistance, with some preparations showing a 50 per cent resistance to atropine. Prazosin, phentolamine, yohimbine, guanethidine, clonidine, and noradrenaline had no consistent effects on the electrically induced bladder contraction. Nifedipine and nimodipine caused a maximum of 65 per cent inhibition of the response. Addition of nimodipine to atropine-resistant strips when maximum atropine inhibition had been reached abolished the contractions. Omitting calcium from the bath solution rapidly abolished the electrically induced contraction. It is suggested that in the normal human bladder the contraction induced by electrical stimulation is mainly atropine sensitive. However, in the functionally disturbed bladder, part of the bladder contraction is atropine resistant, a finding that may have clinical implications.

Adolescent↗
PubMed1981

Priapism--conservative treatment versus surgical procedures.

Fourteen patients with priapism have been treated over the last 12 years. Two patients had a recurrence 2 and 5 years after the primary incident. Abuse of alcohol (often combined with psychotropic drugs) and the use of antihypertensive drugs were the most prominent aetiological factors. Three out of 9 patients treated conservatively and 5 out of 6 patients treated with a shunt procedure have preserved their erection ability. Our results indicate that conservative treatment is not justified and that a shunt procedure should be performed with the least possible delay.

Adult↗
PubMed1981

Antegrade spermatic phlebography in the diagnosis of metastases from testicular tumors.

Antegrade spermatic phlebography was performed in 18 patients in connection with orchiectomy because of testicular expanding lesions and was compared with other diagnostic methods. Fifteen of the cases were teratomas or seminomas. In 6 patients metastases were demonstrated at phlebography and later confirmed. In one case no abnormality was found at phlebography, nor at CT, but at lymphography metastases were found in not enlarged lymph nodes. Due to technical error at phlebography one case was falsely considered abnormal. The technique is described and its use as a screening procedure for metastases is advocated.

Adult↗
PubMed1981

Effects of prazosin on isolated human urethra and in patients with lower motor neurons lesions.

In isolated human urethra, prazosin competitively inhibited contractions induced by noradrenaline, but had no effect on contractions elicited by potassium (127 mM), suggesting an action solely on alpha-adrenoceptors. Seven patients with lower motor neuron lesions and micturition disturbances were treated with 2 mg of prazosin twice daily. Five were investigated by simultaneous urethrocystometry before and during treatment. Prazosin reduced the intraurethral pressure, the intravesical pressure during bladder filling, and autonomous bladder waves. Voiding and incontinence improved in five patients. In one, voiding was facilitated, but continence deteriorated, and in one, no clinical effects were observed. In all patients, residual urine decreased. There were no side effects, except one case of nasal congestion. It is concluded that prazosin effectively reduces alpha-adrenoceptor mediated hyperactivity in the smooth muscle of the lower urinary tract, and that it may be an effective treatment of micturition disturbances in patients with lower motor neuron lesions.

Adolescent↗