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Biomedical subjects

I S Mudraia

Publications and source records attributed to I S Mudraia.

At least 19 recordsLinked to original sources
PubMed1993

[The effect of upper urinary tract interior drainage on urodynamics and contractile function of the ureteral wall].

S-stents were introduced to the upper urinary tracts of experimental dogs on a period from 1 week to 11 months. It was found mild ureter dilation, the increased ureter pressure, refluxes along the upper urinary tract, the lowered flow resistance during perfusion and diuretic loads. Isolated ureter wall fragments demonstrated the diminished contractility in vitro, and the mode of their contractile force adrenergic regulation was modified. The reduced ureter pressure during large flows after indwelling S-stents to the ureters may be the factor that facilitated the renal and ureter stones removing but the decreased contractility and ureter refluxes emphasized that the period of stent implantation to the upper urinary tracts must be pathogenetically and clinically evident.

Animals↗
PubMed1992

[Adrenergic regulation of the contractility of the human and canine ureters].

Investigations on the isolated pieces from upper part of human ureters and upper and lower parts of dog ureters were performed. Isometric contractions during electrical stimulation in Lock solution (37 degrees C) and their changes after adrenomimetic drug and adrenoblocking drug perfusion were studied. The pieces of human ureters had more average weight and rest tension, but less isometric tension during rhythmic electrical stimulation and more pronounced hypersodium contracture in contrast to dog ureters. Adrenaline and noradrenaline augmented contractions of human and dog ureters. Isadrin increased the contractility of the upper parts of human ureters and the lower parts of dog ureters, but decreased--the upper segments of dog ureters. Adrenoblocking agents modified the action of adrenomimetics. After blockade of alpha-receptors by phentolamine, isadrin decreased the contractions of all studied pieces of ureters, however, adrenaline decreased contractility of human ureters but increased--dog ureters. It may be proposed, that there are alpha 1 and alpha 2 receptors, that stimulated the contractility of human and dog ureters, beta 1 adrenoreceptors, that inhibited the contractions during blockade of alpha-receptors, and beta 2-receptors, that in these conditions increased the contractions of dog ureter but decreased the contractions of human ureters.

Animals↗
PubMed1991

[Experimental megaureter in dogs: modeling by "devitalization" of a segment of the ureter and features of the course].

The method of experimental megaureter modelling in dogs that is based on the operative damage of the ureter segment is described. Obstructive megaureter was found in 100% of "devitalization" of the ureterovesical junction and in 59% of "devitalization" of the middle third of ureter. Progression of megaureter symptoms and reduction of evacuator-secretory function on the side of modelling operation without anatomical narrowing of the ureter lumen in 41% of experiments pointed to the actual role of the functional obstruction in pathogenesis of this hard syndrome. In vitro methods demonstrated the decrease of contractility of the "devitalized" fragments and also of above and below situated segments of megaureter. Urodynamic investigations showed the signs of the bioelectrical disturbance in the megaureter wall and the disorder in excitement and contraction of the megaureter, deterioration of the reactivity of the megaureter on the functional loading tests.

Animals↗
PubMed1985

[Inotropic effect of strophanthin in combination with calcium on the heart muscle].

The effect of strophanthine-g and its combination with different concentrations of calcium in Tyrode solution was studied in guinea-pig auriculi atrii contracting under the effect of isometric electric stimulation. Addition to Tyrode solution of strophanthine-g combined with calcium promoted the reduction of the positive inotropic effect of the former substance. During perfusion of the muscles with Tyrode solutions containing no calcium, the maintenance of the contractile function of the muscles is secured adequately enough by addition of strophanthine-g combined with low concentrations of calcium. Combinations of the cardiosteroid and calcium calculated on the basis of the stability constants of their complexes appeared effective. It is inferred that cardiosteroids should be combined with small amounts of calcium in order to attain a positive inotropic effect.

Animals↗
PubMed1977

[Physiological assessment of the method of autohemoperfusion through activated carbon].

The results of study of the sorption properties of phenolformaldehide-activated coal in respect of several physiologically active substances from the physiological saline under static conditoins and under conditions of autohemoperfusion of the limb vessels in experimental animals are presented. Phenolformaldehide-activated coal proved to sorb actively serotonin, adrenaline and noradrenaline, and--to a lesser extent--histamine from physiological saline. Serotonin, adrenaline, noradrenaline, and acetylcholine are sorbed well, histamine--less, papaverine--very weakly from the flowing blood. No alteration of the systemic arterial blood pressure was noted with the inclusion of phenolformaldehide-activated coal into the animal's arterial circulation; a fall of perfusion pressure associated with the decreased vascular resistance occured in a number of cases.

Acetylcholine↗
PubMedDate not supplied

[Comparative assessment of contractility of different sections of the intestine (an experimental study)].

Contractility of different portions of the intestine used for partial or complete replacement of the bladder was studied on the circular fragments of non-inbred rats' intestine. The contractility was studied at rest, in response to electric stimulation, addition to the solution of growing concentrations of cholinomimetic or adrenomimetic drugs, to depolarization of smooth cell membrane with hypersodium solution. It was established that contractility of the large intestine contrary to that of the small intestine is characterized by diminished amplitude of spontaneous contractions. In addition of cholino- and adrenomimetics, amplitude of the phasic and tonic reactions in the large intestine fragments compared to those of the small one was decreased. The conclusion was made that the large intestine is preferable for taking transplants partially replacing urinary bladder to correct its reservoir function whereas small intestinal grafts are more suitable for total replacement of the detrusor.

Acetylcholine↗
PubMedDate not supplied

[Contractile function of ureter in its anomalies in children].

A study on the testing unit was made of a contractile function of ureteral fragments removed at reconstructive operations for vesicoureteral reflux (VUR), neuromuscular dysplasia (NMD) and pelvoureteral segment stricture (PUSS). The study parameters (wall rigidity, amplitude of the contractions, potassium depolarization contracture, responses to adrenoreactive drugs) in patients with VUR were close to normal, whereas in those with NMD or PUSS changed significantly, especially in PUSS patients. Ureteral contractility impairment was heterogenic in all the groups, varying from intact to lost and did not correlate either with age or the disease stage. The value of functional studies of the ureter in reconstructive surgery for specifying the disease pathogenesis, mechanisms of functional decline and individual prognosis of functional efficiency of the operative intervention is discussed.

Adolescent↗
PubMedDate not supplied

[Urodynamics of upper urinary tracts after intestinal plastic surgery on urinary bladder (experimental study)].

In dog experiments, the urinary bladder was replaced for an isolated intestinal segment to test upper urinary tract function as regards configuration of the established urine reservoir early and late after the surgery. Intestinal plastic surgery of the bladder changes parameters of ureteral function in unchanged potential reserve of ureteral contraction. Postileocystoplasty urodynamics of the upper urinary tracts is characterized by lowering of intraureteral pressure, decreased amplitude of ureteral contractions, enhanced tonicity and motility. Plastic replacement of the bladder with isolated intestinal segment is not contraindicated in the solitary kidney.

Animals↗
PubMedDate not supplied

[Functional state of upper urinary tract in urgent extracorporeal lithotripsy].

Seven patients have undergone urgent extracorporeal lithotripsy (UEL) for renal colics. 3 patients were cured. Before UEL they had insignificant defects of urodynamics and ureteral contraction. 3 patients with initial dilation of the upper urinary tracts > 2 cm and reflux ureteral motility, residual concrements eliminated spontaneously or after additional UEL procedures or combined treatment. One female with initial pelvic and uretral dilation and disturbed motility of the upper urinary tracts was treated for 6 months. 1-2.5-year follow-up detected neither concrements nor marked dilation of the calyceropelvic system. Patients with renal colics have more pronounced local defects of contraction rhythm and activity, peristaltic direction. Peristaltic disorders in the upper urinary tracts in patients with renal colics are local and may be related to acute occlusion and neuroreflex effects. This explains why UEL produces good results in renal colics, especially in patients with minimal defects of urodynamics. Complicated course after UEL early after the operation occurred in patients with dilated upper urinary tracts, high contraction amplitude registered by high tonicity of the ureteral wall and the presence of retrograde peristaltic waves.

Humans↗
PubMedDate not supplied

[Internal prosthetic appliance of ureter (experimental study)].

In experiment, endoprosthetic appliances were placed in the intact ureters of 5 dogs, in previously created stricture also in 5 dogs. Three types of endoprostheses were used: nitinol thermo-extensible spiral prosthesis (Russia), reticular extensible vascular endoprosthesis Wallstent (Schneider, Switzerland) and tough teflon biliary prosthesis (Olympus, Japan). The dogs were followed up 1-36 months. Regardless of the prosthesis type, in good patency, in all the cases excretory urography and dynamic nephroscintigraphy demonstrated moderate dilatation of the upper urinary tracts, slowing down of urine evacuation. Urodynamic investigations detected arise in intraureteral basal and peristaltic pressure, transient more frequent contractions above the prosthesis and persistent less frequent contractions of the distal ureter, increased amplitude of the contractions. The contractions became arrhythmic, retrograde waves arose. Later, some dogs had chaotic contractions. It is concluded that endoprostheses reestablish patency of the urinary tracts but hinder contractions in part of the ureter thus affecting negatively urodynamics.

Animals↗
PubMedDate not supplied

[Effects of impaired urodynamics and contractile function of the upper urinary tract on elimination of stone fragments after extracorporeal lithotripsy].

The authors analyze effects of amplitude, tone and frequency of ureteral contractions on elimination of stones fragmented after extracorporeal shock-wave lithotripsy (ECSWL) in 30 patients with concrements in the kidneys and ureters. Before ECSWL the patients had indications for renal pelvis cathetarization. The measurements were made with multichannel impedance ureterography. According to initial dilatation of the upper urinary tracts (UUT), the patients were divided into 3 groups. It is shown that urodynamic UUT disorders determine effectiveness of ECSWL in urolithiasis patients: the greater is the dilatation the more probable are unsatisfactory results of ECSWL. Ureteral contractile activity is essential for rehabilitation in early postoperative period after ECSWL in patients with unrevealed UUT dilation: high amplitude of ureteral contractions in low tone is good for the fragments elimination, while high tone may result to the fragments ejection into the kidney. Low contractility may contribute to development of stone path. In patients with pronounced UUT dilation ureteral contractility is less important for ECSWL effectiveness than the wall tone and retrograde ureteral peristaltic movements. ECSWL results are better in patients with low tone of UUT wall. High UUT tone, especially in combination with retrograde peristaltic ureteral contractions registered prior to ECSWL indicates high probability of residual stones and additional fragmentation procedures irrespective of initial UUT dilation.

Data Interpretation, Statistical↗
PubMedDate not supplied

[Usage of the novel synthetic material carbilan for urinary tract reconstruction in experiment].

Carbilan was tried as a new synthetic suturing material and ureteral prosthesis in reconstruction surgery on the urinary tracts. In experiments on 24 dogs carbilan suturing threads were used for establishment of ureteral-ureteral and vesicoureteral anastomoses, suturing of the ureter, bladder or urethra. In a comparative group of 36 dogs such operations were made using chrome-plated catgut. Complications occurred in 3.8 and 17.6% of the dogs from the carbilan and catgut groups, respectively. Replacement of the part of the ureter in the middle or in the lower third 3-5 cm in length for a carbilan transplant was conducted in 8 dogs. In 6 cases of the suture leaking, the prosthesis underwent deformation and compression by commissures which formed around the flap within 3 months after the implantation. In 2 experiments the prosthesis was sealed with fibrin (a short-term implantation into the artery). This provided normal function of the prosthesis for 9-13 months. Later, the urinary tracts were also obstructed. No occlusions of the prosthesis with urinary salts or detritus were observed. Histologically, both suturing threads and ureteral prosthesis made of carbilan showed good biocompatibility. Massive commissures around the prosthesis arose because of its leaking and contact of the urine with the surrounding tissues.

Animals↗
PubMedDate not supplied

[Urodynamics of the upper urinary tracts after ureteroplasty (experimental data)].

An experimental study on 12 mongrel dogs was made for assessment of urodynamics of the upper urinary tracts after reconstructive surgery. Ureterohydronephrosis was modelled by cryodestruction, confirmed by x-ray and radionuclide examinations. Urodynamics of the upper urinary tracts was studied by measurements of the intraluminal pressure and at multichannel impedance ureterography under thiopental anesthesia. It was found that reestablishment of normal urine passage after ureteroplasty is not accompanied by urodynamic recovery. Preoperative hyperfunction of the upper urinary tracts and their postoperative hypofunction appeared unfavourable prognostic signs for ureteroplasty outcomes.

Animals↗
PubMedDate not supplied

[Functional status of urinary tract after plastic surgery of the urinary bladder with a segment of the ileum (experimental study)].

Replacement of the gall bladder with an isolated ileal segment was made to evaluate function of the urinary tracts depending on configuration of the created urine reservoir early and late after the operation in dogs. Intestinoplasty of the gall bladder changes parameters of ureteral function. Upper urinary tract urodynamics after ileocystoplasty is characterized by lowering of intraureteral pressure, decreased amplitude of the contractions, high tonicity and motility. The intestinal bladder has the same mean basal pressure at rest but less when full than the control animals. Reflex urination after the bladder reconstruction in subtotal resection was intact. Detubulized urinary reservoir had low intravesical pressure and no spontaneous contraction activity.

Animals↗
PubMedDate not supplied

[Role of the level of obstruction and urodynamics of the upper urinary tract in infectious-toxic complications in urolithiasis. (Clinical and experimental study). ].

Clinical studies have revealed that location of the occlusion in the kidney and upper third of the ureter raises the risk of severe infectious-toxic complications of urolithiasis. It is shown experimentally that mechanisms of compensation of impaired urinary transport along the upper urinary tracts differ in obstruction of the upper and lower third of the ureter.

Animals↗
PubMedDate not supplied

[A contractile function of various megaureter forms in infants and its pharmacological regulation].

A total of 43 infants under 3 years of age with organic, functional and reflux obstructive megaureter were studied. The function of the upper urinary tract was examined with dynamic pyeloureterosonography with diuretic load. Contractility of isolated fragments of megaureters and possibility of its pharmacological regulation were studied in patients after surgery in vitro. Different urodynamic variants of the response of refluxing and obstructive megaureters and those with functional obstruction on stimulation of diuresis were established at dynamic pyeloureterosonography with diuretic load. The differences concerned the strength and kind of the reaction, frequency, amplitude and performance of the megaureters (15-30-45 min). In vitro studies confirmed functional differences between the forms of megaureters. The data obtained show preservation of functional reserves of the wall of the refluxing megaureter in children, suppression contractions and reaction of the megaureters with organic obstruction in the ureterovesical anastomosis while functionally obstructive megaureters are able to contract slowly and have reactivity according to the state of the smooth muscle wall. Pharmacological impact on ureteral function by metabolic drugs (picamilone) is determined. A direct action of lasix on the smooth muscle (weakening of high toxic reaction) is proved.

Antioxidants↗