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Biomedical subjects

B Uvelius

Publications and source records attributed to B Uvelius.

At least 73 records · Page 4Linked to original sources
PubMed1990

Metabolism and force in hypertrophic smooth muscle from rat urinary bladder.

Ten days of urinary outlet obstruction in the rat induced a threefold increase in bladder weight. Active force of control and hypertrophic bladder muscle strips was measured at varying PO2 levels after high-K+, carbachol, or electrical field stimulation. Highest force output was obtained with carbachol. Force per muscle area was lower in the hypertrophic muscles. The basal rates of oxygen consumption and lactate formation were similar in the two groups. The metabolic tension cost (ATP turnover/active force) was similar in the two groups for activation with high K+ and carbachol. In anoxia the active force decreased, but this was less pronounced in the hypertrophied muscle. Hypertrophied muscle could, in contrast to the controls, maintain a sustained K+ contracture in anoxia. Basal metabolic rates and tension cost were markedly reduced in anoxia for both groups. The lower force per area with unaltered tension cost, in hypertrophic muscles under all experimental conditions, may reflect unaltered intrinsic properties of the contractile system, although the amount of contractile material has decreased relative to cell volume. The increased resistance to anoxia may reflect a metabolic adaptation to impaired oxygen supply to the hypertrophied tissue.

Animals↗
PubMed1990

Effects of variations in extracellular pH on spontaneous contractile activity and response to nerve stimulation in smooth muscle from rat urinary bladder.

The effects of variations in extracellular pH have been studied on rat detrusor muscle in vitro. At pH 7.4 a continuous low amplitude spontaneous contractile activity was found. At pH 6.75 the contractions became more regular with periods of relaxation between the contractions which had increased in amplitude. At pH 7.85 the reverse was found. The results are interpreted as a membrane effect of pH. No effect of pH on amplitudes of high-K(+)-induced contractures was found. Carbachol dose-response relations and maximal contraction amplitude to carbachol was similar at pH 7.4 and 6.75. A significant depression in response to nerve stimulation was, however, noted at pH 6.75. We suggest that, while the force output of the activated detrusor smooth muscle cell is unaffected by changes in extracellular pH, a prejunctional inhibition of nerve induced contraction might occur at low pH.

Acid-Base Equilibrium↗
PubMed1989

Bladder function in rats with short- and long-term diabetes; effects of age and muscarinic blockade.

The development of alterations in urinary bladder function was studied in rats during six months of streptozotocin-induced diabetes. The results were compared with those obtained in age-matched controls. The bladders from the control rats developed with increasing age an increased micturition volume, a decreased micturition interval, and increased bladder compliance and capacity despite an unaltered bladder weight and unaltered passive and active length-tension relations. The effects of muscarinic blockade were somewhat more pronounced in the older control rats. Following streptozotocin 24 hour diuresis increased rapidly to stabilize within two weeks at a level 15 times higher than the original. This was accomplished initially by an increase in the micturition frequency and then gradually by an increased micturition volume. After six weeks bladder weight had increased more than twofold and did not increase further with time. Despite this both micturition volume and bladder capacity increased from six weeks to six months of diabetes. The diabetic bladders had at low frequencies of stimulation a higher resistance to scopolamine than their age-matched controls. At higher frequencies the resistance to muscarinic blockade showed a similar decrease with age as for the controls. The more pronounced decrease in micturition pressure following atropine treatment in six weeks diabetic rats thus suggests an increased excitation frequency during micturition. No supersensitivity to carbachol was found even after six months of diabetes.

Aging↗
PubMed1988

Contents and effects of substance P and vasoactive intestinal polypeptide in the bladder of rats with and without infravesical outflow obstruction.

The concentrations of substance P and vasoactive intestinal polypeptide (VIP) were determined in the upper, middle, and lower part of the bladder of rats with and without infravesical outflow obstruction. In the obstructed animals there was a significant increase in bladder weight and the total amounts of substance P and VIP were increased. However, the concentrations of substance P were significantly lower than in the control bladders. The concentrations of VIP, on the other hand, were significantly higher in the middle and lower parts of obstructed bladders than in the controls. In isolated strips of the normal and obstructed bladders VIP had neither contractile nor relaxant effects. The peptide had no effect on electrically induced contractions. Substance P produced concentration-dependent contractions in both normal and obstructed bladders. However, obstructed bladders were significantly less sensitive than controls. It is concluded that the bladder instability seen in rats with infravesical outflow obstruction cannot be explained only in terms of changes in the bladder content of substance P or VIP.

Animals↗
PubMed1988

Reversibility of detrusor hypertrophy and hyperplasia after removal of infravesical outflow obstruction in the rat.

The present investigation was performed in order to study the degree of reversibility of changes of the rat detrusor secondary to infravesical outflow obstruction for various periods of time. In a previous study it was shown that outflow obstruction induced both hypertrophy and hyperplasia of the smooth muscle cells. This was determined by means of morphometry and analyses of DNA and RNA. The results of the present investigation confirm the findings of previous studies that these changes to a considerable extent are reversible after removal of the outflow obstruction. This seems to be true both in animals obstructed for a short period of time (10 days) and in animals where the hypertrophy and hyperplasia processes have diminished (six weeks).

Animals↗
PubMed1988

Cystometrical and in vitro evaluation of urinary bladder function in rats with streptozotocin-induced diabetes.

Micturition pattern and cystometric characteristics were determined in control rats, and in rats with streptozotocin-induced diabetes (six weeks duration). The diabetic rats had an increased frequency of micturition, an increased micturition volume, and an increased 24 hr. urinary output. The cystometry showed that the diabetic bladders had an increased compliance and a higher threshold volume for initiating a micturition reflex. No spontaneous rhythmic contractions were seen during the filling phase, and no residual urine could be detected. While micturition pressure increased, the micturition time was virtually unaltered. In vitro a right-ward shift for passive and active length-tension relations was noted. The observed changes in cystometric characteristics and length-tension relations might probably be explained on the basis of adaptive changes to the increased diuresis involving both sensory and motor control of the urinary bladder.

Animals↗
PubMed1988

Different effects of neuropeptide Y on electrically induced contractions in the longitudinal and circular smooth muscle layers of the female rabbit urethra.

The effects of neuropeptide Y (NPY) on preparations of isolated longitudinal and circular smooth muscle from rabbit urethra were studied. In both types of muscle, electrically induced contractions and relaxations could be abolished by tetrodotoxin, (TTX). In the longitudinal muscle preparations the contraction was slightly reduced by prazosin, but markedly reduced by scopolamine and NPY. The NPY effect was not influenced by pretreatment with rauwolscine. Pretreatment with NPY had no effect on contractions induced by noradrenaline (NA) or carbachol and the peptide did not relax preparations contracted by these agents. In circular muscle an initial, fast response, not sensitive to prazosin or scopolamine was occasionally observed following electrical stimulation. A slow contraction component was regularly seen; this response was abolished by prazosin. Neuropeptide Y did not influence any of these responses. The preparations were concentration-dependently contracted by NA, whereas carbachol had no effect. Pretreatment with NPY did not affect contractions induced by NA, nor did the peptide relax NA-contracted preparations. In neither longitudinal nor circular muscle strips did NPY affect the electrically induced TTX sensitive relaxation of NA-contracted preparations. The results suggest that in the rabbit urethra NPY reduces contractions in the longitudinal muscle layer by selectively inhibiting the release of acetylcholine from cholinergic nerves. Neuropeptide Y did not appear to have any significant postjunctional effects nor to interfere with the release, or effects of NA or other transmitter agents. The physiological importance of the urethral effects of NPY remains to be established.

Animals↗
PubMed1987

Bladder vasodilatation and release of vasoactive intestinal polypeptide from the urinary bladder of the cat in response to pelvic nerve stimulation.

In the feline urinary bladder blood flow was determined by means of a direct blood flow measurement technique before and during pelvic nerve stimulation. Simultaneous sampling of venous blood from the bladder was performed, and the output of vasoactive intestinal polypeptide (VIP) was determined by means of radioimmunoassay. Maximal stimulation of the pelvic nerves led to a clearcut increase in intravesical pressure and a small but sustained increase of blood flow in the bladder wall. These changes were associated with a drastic increase in VIP output from the bladder, increasing from a control level of 0.2 fmol./min. to 15 fmol./min. during stimulation. The results suggest that VIP might be the neurotransmitter responsible for the vasodilatation in the feline urinary bladder in response to pelvic nerve stimulation. The discrepancy between the moderate blood flow increase and the pronounced increase in VIP-release might, however, indicate that VIP exerts its main effects elsewhere in the bladder than in the vascular bed, for instance the detrusor smooth muscle.

Animals↗
PubMed1987

Cystometrical evaluation of bladder instability in rats with infravesical outflow obstruction.

Cystometries were performed in normal rats and in rats with bladder hypertrophy due to infravesical outflow obstruction. Investigations were performed in the presence and absence of anesthesia. pentobarbital anesthesia depressed spontaneous contractile activity in the bladder and the micturition reflex, thereby making measurements of other variables, such as bladder capacity and residual volume, impossible. In conscious animals infravesical outflow obstruction led to development of increased bladder capacity, marked residual volume, and unstable detrusor contractions. The model seems to be well suited for further evaluation of the mechanisms involved in the development of detrusor instability and the responses to pharmacological treatment.

Anesthesia, General↗
PubMed1987

Ornithine decarboxylase activity and polyamine content in normal renal tissue and in renal carcinoma.

Ornithine decarboxylase (ODC) activity and contents of putrescine, spermidine and spermine were determined in cortical and medullary tissue and clear cell tumours in human kidneys. Medullary ODC activity was 75 +/- 9% (n = 6; p less than 0.05) of the respective cortical value. The ODC activity in renal tumours varied considerably but did not differ significantly from the respective cortical values. Similar concentrations of putrescine were found in cortex and medulla, but a 5-fold increase was found in the tumours (p less than 0.02). Significantly lower values (p less than 0.01) of spermidine and spermine were found in medulla when compared to cortex. No significant change was found for these amines in the carcinomas when compared with corresponding cortical tissue.

Adult↗
PubMed1987

Transient ischemic colitis. Case report.

A 78-year-old man had profuse bloody diarrhea of sudden onset following a traffic accident associated with mild hypothermia. Rectoscopy performed one day later showed severe acute inflammatory changes, and biopsy revealed acute necrotizing colitis. Treatment was conservative. At control colonoscopy 3 weeks later the mucosa was mainly normal.

Accidents, Traffic↗
PubMed1986

Lithium lowers renal, cardiac and splenic ornithine decarboxylase activity in mice.

A single i.p. injection of lithium chloride (5-7.5 mumoles/g b.wt) in mice caused a 70-80% decrease in renal, cardiac and splenic ornithine decarboxylase (ODC) activity within 1 h, whereas pulmonary ODC activity was unaffected. Lithium chloride did not have any effect on ODC activity in vitro when added to homogenates of the tissues studied. We suggest that the effect of lithium on ODC activity is not direct, but mediated via e.g. hormonal or nervous influence.

Animals↗
PubMed1986

Detrusor smooth muscle in rats with alloxan-induced diabetes.

Following five weeks of alloxan-induced diabetes, female rats were killed and the urinary bladder was used either for organ bath experiments, collagen determination or electron microscopy. Mean bladder weight increased from 70 +/- 3 (SE, n = 8) for controls to 131 +/- 7 mg. (n = 9) for the diabetic rats. Collagen concentration decreased from 104 +/- 5 (n = 8) to 69 +/- 4 (n = 9) micrograms/mg. but due to the weight gain total bladder collagen increased from 7.4 +/- 0.6 to 8.9 +/- 0.3 mg. Electron microscopy indicated an increase in mean cross-sectional area of the detrusor smooth muscle cells from 8.1 +/- 0.5 (n = 132) to 19 +/- 0.9 (n = 144) mu 2. Despite these changes the bladders from diabetic animals and the controls had similar characteristics with regard to nerve mediated frequency-response relations, atropine resistance, responses to alpha-agonists and high-K+ solution. No functional neurogenic lesion and no impairment of smooth muscle cell contractility could thus be detected, and it is proposed that the bladder hypertrophy in the diabetic animals is due to a physiological adaptation to the four-fold increase in urinary production.

Animals↗
PubMed1986

Detrusor collagen content in the denervated rat urinary bladder.

Neurogenic bladder dysfunction was created in male rats by removal of the pelvic ganglia. The bladders were then emptied manually once daily, and kept free from infection. After 10 days or six weeks the bladders were taken out and the mucosa-submucosa was removed. The detrusors were then weighed and used for collagen assay. Detrusor weight increased 4.5 and six times after 10 days and six weeks, respectively. Total detrusor collagen increased 2.3 and 3.7 times, but due to the increase in detrusor weight the concentration decreased to 60 per cent of normal. The electron microscopic investigation showed that the cross-sectional area of the smooth muscle cells had increased fourfold after six weeks. The collagen fibrils were found mainly in the interstitial tissue between the muscle bundles. As these increased in size following the neurogenic lesion, the collagen-rich tissue component decreased relatively. Our conclusion is that frequent emptying and the avoidance of bladder infection protects the denervated rat urinary bladder wall from injuries that would otherwise lead to an increased collagen concentration.

Animals↗
PubMed1986

Healing of esophagojejunal anastomoses after experimental total gastrectomy. A comparative study using manually sutured or stapled anastomoses.

In construction of the eosphagojejunostomy after total gastrectomy, the EEA stapled (US Surgical Corporation, Norwalk, CT) and the two-layer interrupted 3-0 Dexon anastomoses are compared concerning the radiological appearance, breaking strength, circulation, and collagen concentration. Thirty female pigs were used. After total gastrectomy and Roux-en-Y preparation, the pigs were randomized to achieve sutured or stapled anastomoses. 141Ce-labeled microspheres were used for measurements of anastomotic blood flow. After the pigs were killed, the breaking strength of the anastomosis was recorded, the collagen content determined, and an anastomotic index calculated comparing two perpendicular diameters in the anastomosis and 5 cm above. Breaking strength, leakage frequency, and anastomotic index were the same in the two groups. One week after surgery, there was a significant increase in anastomotic circulation (p less than 0.05) in both the sutured and the stapled anastomoses compared to controls. Collagen increased equally with time in the two groups (p less than 0.01). The stapled esophagojejunostomy was faster to perform (20 min) than the sutured (28 min) (p less than 0.05).

Animals↗
PubMed1986

Pleomorphic adenoma in the breast of a human female. Aspiration biopsy findings and receptor determinations. Case report.

A case of multiple pleomorphic adenomas ("mixed" tumour of salivary gland type) of the breast is reported. This rare benign tumour can be misinterpreted as a malignant tumour both clinically and radiologically. The aspiration biopsy findings suggested cystosarcoma phyllodes. Oestrogen and progesterone receptor determinations revealed medium high levels, comparable to carcinoma of the breast.

Adenoma, Pleomorphic↗
PubMed1985

Origin and distribution of neuropeptide Y-, vasoactive intestinal polypeptide-and substance P-containing nerve fibers in the urinary bladder of the rat.

The origin and distribution in the urinary bladder of nerve fibers containing neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP) and substance P (SP) were investigated in rats. Experimental procedures comprised preganglionic decentralization or postganglionic denervation of the bladder and also chemical sympathectomy as well as capsaicin treatment of newborn rats. Nerve fibers containing NPY were richly distributed in the detrusor muscle and also in the pelvic ganglia. Numerous NPY-containing nerve cell bodies were found in pelvic ganglia. A rich occurrence of VIP fibers and a more sparse distribution of SP-containing fibers were also found in the bladder as well as a relatively rich representation of VIP-containing nerve cell bodies in the pelvic ganglia. After decentralization the intensity of VIP and NPY immunofluorescence increased in nerve cell bodies of the pelvic ganglia and in nerve fibers in the wall of the bladder. Postganglionic denervation, on the other hand, eliminated all peptides examined in the bladder wall. After postganglionic denervation the situation in the ganglia was approximately the same as after decentralization. Chemical sympathectomy (6-OHDA) did not seem to change significantly the frequency and distribution of VIP-, SP- and NPY-fibers in the muscle layer of the bladder or in the pelvic ganglia, while the NPY-containing nerve fibers in the submucosal layer and around blood vessels of the bladder disappeared. Adrenergic nerve fibers in the wall of the bladder (visualized by histofluorescence) were markedly reduced in number after administration of 6-OHDA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗