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PubMed1997

Implementation of intussusceptive microvascular growth in the chicken chorioallantoic membrane (CAM).

Intussusceptive microvascular growth (IMG) is a new mechanism of capillary growth: The vascular network expands by insertion of newly formed columns of interstitial tissue (interstitial tissue structures) into the vascular lumen called tissue pillars or posts (diameter: 0.5-2.5 microm). IMG has so far been described during organ development and growth and in tumor angiogenesis. Different modes of its implementation could be demonstrated in the rat lung and the chicken chorioallantoic membrane (CAM). In the present investigation a further mechanism of IMG is reported in the chicken CAM: tissue pillars form by splitting of larger interstitial tissue structures and intercapillary walls located between neighboring capillary segments which will consecutively fuse. Splitting is dependent on the existence of a pillar's core composed of a bundle of collagen fibrils ensheathed by extensions of endothelial-like cells inside these structures. Pillar cores thus represent the smallest unit of interstitial tissue around which the vascular lumen might expand. This mode of IMG is obviously connected to physiological remodeling of the capillary network and appears to be dominant during later stages of CAM development.

Actin Cytoskeleton↗
PubMed1997

Quantitative study of intussusceptive capillary growth in the chorioallantoic membrane (CAM) of the chicken embryo.

In an attempt to sort out the respective contributions of sprouting and intussusceptive microvascular growth (IMG) during chicken chorioallantoic membrane (CAM) development, we analyzed the morphology and the quantitative growth of the capillary bed of the CAM by light microscopy. By perfusing the CAM microvasculature with highly concentrated colloidal gold particles, the capillaries could be unambiguously distinguished from the surrounding unlabelled tissue. This allowed us to identify, count and measure the intercapillary tissue profiles. By means of morphometric analysis we could show that CAM angiogenesis undergoes three phases of development. In an early phase, from Day 5 to Day 7, the major mechanism of capillary network growth is sprouting. In an intermediate phase, from Day 8 to Day 12, IMG is prevailing, and at Days 13 and 14, CAM structure is undergoing expansion with only a small increase in complexity. These findings are important in view of experimental protocols using the CAM as a model for testing angiogenetic factors. Indeed, care has to be taken not to misinterpret normal age-dependent alterations of the CAM vascular architecture as specific responses to tested agents.

Allantois↗
PubMed1998

TIE1 and TIE2 receptor tyrosine kinases inversely regulate embryonic angiogenesis by the mechanism of intussusceptive microvascular growth.

As shown previously, TIE1 and TIE2 receptor tyrosine kinases are specifically expressed in endothelial cells during embryonic angiogenesis. A detailed analysis of the vascular malformations of homozygous mice for a targeting mutation of both receptors was performed at the histological and cellular level. The data demonstrate that the TIE1 and TIE2 receptor inversely and concomitantly mediate interactions between endothelial cells with their extracellular matrix and with surrounding mesenchymal cells. These interactions are obviously crucial for normal endothelial cell motility and/or attachment and also for recruitment of periendothelial cells. The analysis of the TIE2-deficient embryos demonstrates how these cell/cell- and cell/matrix interactions subsequently influence the formation of normally structured tissue folds that divide the vessel lumen. They are also essential for the formation of vessel loops that compose a new vascular network and for the development of the ventricle in the heart. Fold and loop formation follow the principles of intussusceptive microvascular growth. The localization of the cardiovascular malformations corresponds to the temporal and spatial expression pattern of the TIE2 receptor. Angiopoietin-1, a ligand that activates the TIE2 receptor, is expressed in mesenchymal cells surrounding the endothelium. This local relationship is indicative of a paracrine regulation.

Angiopoietin-1↗
PubMed1992

Intussusceptive microvascular growth, a new mechanism of capillary network formation.

Growth by intussusception is defined as growth by deposition of new particles or pieces of formative material among those already embodied in a tissue or structure. In the context of capillary growth the term stands for the extension of the capillary system by the insertion of new capillary meshes within the existing network. New meshes arise as slender transcapillary tissue pillars. These are formed initially by a circumscribed fusion of opposite endothelial leaflets. Following reorganization of the junctional complexes, the pillar is invaded by interstitial tissue. This means that for the formation of new capillaries no sprouting of endothelial cords or tubules is required. The mechanism is described in the growing lung, but may occur in other tissues too. There may be a chance for in vivo observation of the process in the capillaries of the chorio-allantoic membrane of the chicken.

Aging↗
PubMed1996

Detubularized right colonic reservoir with intussuscepted ileal nipple valve or stapled ileal ("Lundiana") outlet. Clinical and urodynamic results in a prospective randomized study.

In a prospective randomized study, patients undergoing cystectomy and continent urinary diversion by means of a detubularized right colonic reservoir were randomized to one of two types of outlet: either an intussuscepted ileal nipple valve (n = 15) or a stapled ileal ("Lundiana") outlet (n = 15). There were no early complications from the reconstruction. Subsequently, one ileal nipple outlet required revision because of progressive catheterization difficulties. In the Lundiana group, perforation of the reservoir occurred in one case and a narrow stomal opening was revised in local anesthesia in two cases. Urodynamic assessment revealed similar pressures at rest for the two outlets. At stress (concomitant with reservoir contraction), there was a distinct increase in outlet pressure in the nipple valves, but this was rarely encountered in the Lundiana group. Questionnaires showed episodes of urinary leakage to be more common in the Lundiana group, whereas the reverse applied to catheterization difficulties. In both groups, however, the great majority of patients were satisfied or very satisfied with the function of the urinary tract.

Adult↗
PubMed1989

Intussusception ureterectomy.

A modification of intussusception ureterectomy is described. Dilatation of the ureter is unnecessary before the procedure and closure of the bladder wall defect is recommended to avoid urine extravasation.

Dilatation↗
PubMed1998

Preputial intussusception or acquired megaprepuce.

Preputial intussusception, or acquired megaprepuce, is a clinical condition whose incidence is increasing. It results from infolding of the outer preputial skin, obstruction of urinary flow, and the development of a phimosis. With time the process continues, resulting in a distinctive clinical picture. Treatment by early circumcision cures the problem and allows resolution of the sequelae.

Humans↗
PubMed1990

Intussusception-type antireflux valve in the Roux-en-Y loop to prevent ascending cholangitis after hepatic portojejunostomy.

An intussusception-type antireflux valve was created in the Roux-en-Y loop in 23 infants with biliary atresia (17 new cases, and six others after episodes of ascending cholangitis) and 10 patients with congenital bile duct dilatation, in order to prevent ascending cholangitis after hepatic portojejunostomy. Mesenteric blood vessels were divided in a 4 cm length of the Roux-en-Y loop, and the distal 1.5 cm of this portion was further denuded of the seromuscular layer; an antireflux valve was thus established by invaginating the proximal portion into the denuded jejunum. No case, in which this technique was used, was associated with any surgical complications, and ascending cholangitis never developed in any of the 17 new cases with biliary atresia, during an average follow-up of 32 months.

Anastomosis, Roux-en-Y↗
PubMed1977

Ileal substitute of ureter with reflux-plasty by terminal intussusception of bowel: animal experiments and clinical experience.

The conflicting results reported after substitution of the ureter by isolated bowel segments suggest that the procedure is still hazardous. This induced us to check experimentally the performance of the ileal ureter with antireflux-plasty before using it clinically. The antireflux mechanism is constructed by intussuscepting the terminal 8 cm. of an isolated ileal segment into each other thus forming a nipple. After vesicoileostomy the nipple protrudes into the urinary bladder. In the pig vesicoileorenal reflux was prevented, and anterograde urinary flow from the kidney through the ileal ureter into the bladder was unobstructed. Finally, the case of a patient is recorded who was submitted to the same procedure successfully.

Animals↗
PubMed1979

Transvesical intussusception (Lich) ureterectomy.

Intussusception ureterectomy has been used to excise prophylactically the distal ureter in 10 patients with carcinoma of the renal pelvis. The procedure has proved safe and expeditious, as well as permitting more precise excision of the surrounding vesical mucosa.

Adult↗
PubMed1983

Total nephroureterectomy with ureteral intussusception and transurethral ureteral detachment and pull-through.

We describe a technique for nephroureterectomy that includes ureteral intussusception and transurethral ureteral resection and our method for transurethral ureteral pull-through. These adjuncts permit total nephroureterectomy through a single skin incision and are appropriate in all cases except in patients with known high-grade transitional cell carcinoma of the renal pelvis or ureter. In 18 cases, these techniques have been shown to be reliable, safe, and rapid; in the 14 patients under observation for five years or longer, there have been no local recurrences of tumor.

Aged↗
PubMed1990

Urodynamic evaluation of patients with continent urinary diversion using cecal reservoir and intussuscepted ileocecal valve.

Patients requiring bladder removal for malignant disease have undergone continent urinary diversion employing the ileocecal segment, using the cecum to construct a reservoir and an intussuscepted ileocecal valve as the continence mechanism. Five of these patients have been studied urodynamically and radiographically in the postoperative period. Incontinence was found to be minimal and related only to a prolonged catheterization interval. Passive filling pressure and peristaltic pressure remained low in all patients and was lower than the nipple valve pressure in 4 of 5 patients. A transient increase in reservoir pressure at capacity with peristalsis exceeded the nipple peristaltic pressure in 1 patient and was associated with a small volume of incontinence. This resolved with a shortened catheterization interval. Reflux was not found in any subject studied. These studies indicate that the cecal segment can be used to construct a continent urinary reservoir that provides satisfactory function for the patient while maintaining an acceptable pressure volume relationship.

Aged↗
PubMed1993

Distal intussusception of processus vaginalis: a cause of acute hydrocele.

Acute obstruction of a patent processus vaginalis occurred in two boys, mimicking incarceration of an inguinal hernia. In fact, obstruction was caused by an intussusception of the processus vaginalis forming an intussuscipiens that occluded the hernia sac. This lesion, described previously in 1896 and in 1974, is one of the mechanisms by which an asymptomatic hernia or hydrocele becomes acutely symptomatic.

Acute Disease↗
PubMed2004

Computational model of flow-tissue interactions in intussusceptive angiogenesis.

Angiogenesis, the growth of vascular structures, is a complex biological process which has long puzzled scientists. Better physiological understanding of this phenomenon could result in many useful medical applications such as the development of new methods for cancer therapy. We report on the development of a simple computational model of micro-vascular structure formation in intussusceptive angiogenesis observed in vivo. The tissue is represented by a discrete set of basic structural entities and flow conditions within the resulting domain are obtained by solving the Navier-Stokes equations. The tissue is then remodelled according to the tangential shear stress while approximating advection by means of simple non-diffusive heuristics. The updated tissue geometry then becomes the input for the next remodelling step. The model, consisting of steady-state flow and a simple mechanistic tissue response, successfully predicts bifurcation formation and micro-vessel separation in a porous cellular medium. This opens new modelling possibilities in computational studies of the cellular transport involved in micro-vascular growth.

Capillaries↗
PubMed1983

The role of a modified intussusception jejunocolic valve in short-bowel syndrome.

Short-bowel syndrome results in malabsorption and malnutrition producing profound metabolic disorders. Attempts to correct this problem with various surgical procedures have so far proved unsuccessful. Studies made in our laboratory using experimental animals, showed that a modified jejunocolic intussusception valve appears to be effective in prolonging the small-bowel transit time and the absorptive capacity of the intestines in short-bowel syndrome. Furthermore, construction of the valve is uncomplicated and unaccompanied by any mortality or morbidity.

Animals↗
PubMed1994

Retrograde ureteral intussusception.

A soft tissue mass causing ureteral obstruction should be considered malignant until proved otherwise. We report a case of retrograde ureteral intussusception that caused obstruction. To our knowledge, this condition has not been described in the recent literature.

Female↗
PubMed1992

Urethral controlled bladder substitution: a comparison between the intussuscepted nipple valve and the technique of Le Duc as antireflux procedures.

A urethral controlled bladder substitute was constructed from a detubularized, double folded ileal segment in 40 male patients following cystoprostatectomy for bladder cancer. For reflux prevention patients were prospectively randomized to receive either an intussuscepted nipple valve or the ureters were implanted by the Le Duc mucosal trough technique. All patients had normal upper tracts preoperatively. Mean patient age, performance status and stage of cancer were comparable in both groups. Patients were evaluated 6 to 18 months postoperatively. In addition to history taking, assessment included excretory urography, ascending cystography and voiding cystourethrography. During the observation period all patients with nipple valves had normal radiographic appearance of the upper tracts without evidence of reflux. On the other hand, following the Le Duc procedure 12 of 38 renal units (31%) showed evidence of radiographic dilatation. Of the 12 units 11 had stenotic ureters and 1 had reflux. We conclude that nipple valves are more effective in reflux prevention and protection of the upper urinary tract in patients for whom an ileal neobladder is indicated.

Humans↗
PubMed1992

Tapering of intussuscepted ileal nipple valve or ileocecal valve to correct secondary incontinence in patients with urinary reservoir.

Malfunction of the outlet mechanism, that is leakage of urine or difficulty in catheterization, has been the main problem in the evolution of continent urinary reservoirs. Urinary leakage in 3 patients with a right colonic reservoir (2 with an intussuscepted ileal nipple valve and 1 with a plicated ileal segment as a continence mechanism) was managed with tapered narrowing of the nipple valve and the ileocecal valve, respectively, using stapling techniques. Continence was thereby reestablished without impeding catheterization. Tapering is easy to perform and, when applicable, can obviate the need for a major surgical procedure.

Adult↗