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PubMed1988

[Development of a small caliber vascular graft using a connective tissue tube with temporary antithrombogenicity].

A connective tissue tube containing collagen fibrils and capillary blood vessels is an ideal material for artificial artery, since the collagen fibrils compose an excellent supporting framework for cell migration and proliferation and the endothelial cells of the capillary can be the origin of the endothelialization of the graft. However, its thrombogenicity has remained a problem. This experiment was designed to develop a small caliber (3mm) vascular graft using an autogenous connective tissue provided with temporary antithrombogenicity. A tube knitted of ultra-fine polyesters was implanted subcutaneously in the back of mongrel dogs for three weeks. Thus accomplished connective tissue grafts were heparinized ionically in vitro, using cross-link agents. Then the treated grafts, 5-6 cm in length and 3mm in diameter, were segmentally replaced with bilateral carotid arteries. During the follow-up period up to 55 days, 7 of 8 grafts (88%) were patent. Histological examinations revealed that there was no thrombus and the neointima formation with a lining of endotherial cells was completed, extending overall length of the grafts. Thus, newly devised hybrid type of connective tissue graft is thought to be usefull for a replacement for arteries with a small caliber.

Animals↗
PubMed1992

[Pelvic thrombosis and uterine fibroids].

The association of thrombosis with an abdomino-pelvic mass should suggest that there is a malignant tumour present, and aetiology must be explored. All the same it is not possible to exclude a benign mass as the cause of the thrombosis. The anatomy of the blood vessels in this region make it more likely that the phlebitis will be on the left side. As far as the physiopathology is concerned the pressure on the vessels is associated probably with an increase in fibrous tissue, and perhaps a local excretion of tissue thromboplastin. The principal complications are: pulmonary embolus, or gangrene of the leg as a primary complication and also as a secondary post-phlebitic complication. Treatment with Heparin prescribed in every case in the correct doses. When the thrombosis is recent and threatening direct surgery may avoid the short and long term consequences. If thrombectomy is not indicated urgently surgery can be postponed unless the tumour is growing rapidly. It is important to avoid migration of the clot during the operation, and this is best done by putting a temporary clip on the vena cava which will avoid the serious vascular consequences after phlebitis and surgery.

Adult↗
PubMed2000

Binary Black Hole Mergers from Planet-like Migrations.

If supermassive black holes (BHs) are generically present in galaxy centers, and if galaxies are built up through hierarchical merging, BH binaries are at least temporary features of most galactic bulges. Observations suggest, however, that binary BHs are rare, pointing toward a binary lifetime far shorter than the Hubble time. We show that, almost regardless of the detailed mechanism, all stellar dynamical processes are too slow in reducing the orbital separation once orbital velocities in the binary exceed the virial velocity of the system. We propose that a massive gas disk surrounding a BH binary can effect its merger rapidly, in a scenario analogous to the orbital decay of super-Jovian planets due to a proto-planetary disk. As in the case of planets, gas accretion onto the secondary (here a supermassive BH) is integrally connected with its inward migration. Such accretion would give rise to quasar activity. BH binary mergers could therefore be responsible for many or most quasars.

Journal Article↗
PubMed2004

Effect of morphological properties of transferred embryonic stages on tubal migration Implications for in vivo culture in the bovine oviduct.

In cattle, there is no practical method, which allows tubal transfer of pre-implantation embryos for routine in vivo culture as it has been established in sheep. The aim of our study was to perform tubal transfer by transvaginal endoscopy in synchronized heifers, in order to expose embryos at various embryonic stages to the physiological mechanisms of migration in the non-ligated oviducts. Various embryonic stages were transferred by transvaginal endoscopy into the oviducts of temporary recipients and were recovered on Day 7. The transfer of embryos in hyaluronate containing medium ("Hyaluronan"), zygotes stripped of cumulus ("Denuded Zygotes"), embryos embedded in cumulus ("Zygotes with Cumulus"), matured oocytes with capacitated spermatozoa ("GIFT") or embryos embedded in Na alginate ("Alginate") led to increasing recovery rates (13, 30, 56, 63 and 71%, respectively). However, the developmental rate on Day 7 was adversely affected (16, 11, 8, 16 and 8%), whereas the blastocyst rate on Day 8 showed more balanced results (17, 14, 18, 21 and 11%). Our data demonstrate that the structural properties of transferred embryos affect tubal migration and are crucial for subsequent in vivo culture. Embryos enclosed in cumulus cells or alginate synchronize more successfully with the oviductal transport systems than denuded stages or embryos in hyaluronate containing medium.

Alginates↗
PubMed1977

The effect of locally injected vasoactive amines on the elicitation of delayed-type hypersensitivity.

In previous work monoamine depletion due to treatment with reserpine was shown to decrease the elicitabiltiy of DTH responses in mice. In addition, treatment with monoamine oxidase inhibitors prevented the reserpine-induced decrease. These findings led to the suggestion that serotonin-induced increased vascular permeability is necessary to the development of DTH reactions, perhaps by allowing bone marrow-derived macrophage precursor cells, which are obligate components of DTH responses, to migrate through specialized venules into the site of the reaction. We have compared classical drug tachyphlaxis (temporary inhibition of the effects of a drug by prior treatment with agonists) to serotonin in vessels of mouse feet with local inhibition of DTH after serotonin pretreatment of mice. During the tachyphylactic period, DTH responses are depressed. This suggests that serotonin-induced tachyphylaxis of local endothelial receptors can be responsible for DTH inhibition. In contrast, local injection of histamine has no effect on DTH and this drug is a much less potent inducer of tachyphylaxis to serotonin-mediated vasoactive reactions. On the other hand, histamine can inhibit in vitro T cell reactions, which are not affected by serotonin. These data help to further the concept that serotonin plays an important role in the regulation of DTH in mice and that it probably does so by acting on vascular endothelium.

Animals↗
PubMedDate not supplied

Venous interruption as prophylaxis of pulmonary embolism: vena cava filters.

Interruption of vena cava for prevention of pulmonary embolism (PE) was achieved in the past with surgical ligation or placement of clips outside the infrarenal vena cava. At present, this procedure is performed with percutaneous insertion of vena cava filters. Vena cava filters can be permanent or temporary, catheter-retrievable. Main indications for placement of a vena cava filter are: contraindication for anticoagulant therapy in patients with severe PE in whom a further embolic episode would be fatal or patients with PE (or its recurrence) undergoing adequate anticoagulant therapy. Temporary filters are reserved to patients where the risk of PE is limited in time as in posttraumatic, post-partum or postoperative thromboembolism. The incidence of recurrence after placement of a vena cava filter varies between 0.5 and 7%. Procedure-associated complications are usually mild. However, severe complications as filter migration into the pulmonary artery or vena cava perforation were described. Our experience concerns the insertion of 61 vena cava filters (47 permanent and 14 temporary). Indications were as follows: iliofemoral thrombosis at embolic risk (37 cases), contraindication for anticoagulant therapy in the presence of deep vein thrombosis with embolic risk (7 cases), protection during fibrinolytic therapy (3 cases), PE during anticoagulant therapy (5 cases) complications of anticoagulant therapy which required discontinuation (5 cases), prophylaxis in view of surgery at high risk for PE (2 cases), protection for surgical venous thrombectomy (2 cases). Mortality was nil. Clinically evident PE was not observed in any patient in whom vena cava filter was inserted. Complications were mild and asymptomatic. Vena cava filters represent an effective prevention of PE together with medical and surgical treatment. At present, problems of this procedure are not technical but rather concern correct indications. Interruption of vena cava is effective if planned within a global strategy for prevention of thromboembolism.

Adolescent↗
PubMed1988

[A totally implantable permanent central venous access, long-term experience with subcutaneous infusion chambers].

Subcutaneously implanted infusion chambers represent a new method of central venous access. In 57 evaluable out of 70 patients, four different models of infusion chambers with an accumulative observation time of 57 years were implanted. In 72% of the patients, up to 12 cycles of polychemotherapy were administered. Parenteral nutrition and blood drawing were also performed. After 4,970 punctions of the system and 12.2 years of use 46 complications in 38 patients were observed, however, most were minor ones, such as temporary occlusions (12) and extravasations (14). Septum luxation (1), septum perforation (1), catheter fracture (1) and catheter migration (2) as well as 7 cases of septicemia or port-pocket-infection required explanation. Infusion chambers seem to be particularly suitable for intermittent and long-term chemotherapy and emergency bolus injections with a significant advantage (10 complications per one thousand days of use) compared to externally placed venous catheters. However, follow-up and care must be performed by a skilled team.

Adolescent↗
PubMed2000

Treatment of chronic pain by spinal cord stimulation.

Chronic pain after injury of the nervous system is difficult to treat. This report describes our experience in the treatment of chronic pain by spinal cord stimulation (SCS) in four patients (three men and one woman, with ages ranging from 61 to 73 yr). One patient had chronic intractable pain due to a spinal cord injury, one had post-herpetic neuralgia, one had failed back surgery syndrome, and one had brachial plexus and spinal cord injuries. A permanent spinal cord stimulator was implanted in the patient with spinal cord injuries. In the other three patients, a permanent spinal cord stimulator was implanted after a successful trial stimulation with temporarily implanted electrodes. After 19 to 25 months (mean, 21 mo) of follow-up, three patients had satisfactory improvement of pain and one patient had temporary pain relief, but pain recurred two months after implantation. One patient had recurrence of pain after migration of an electrode, and the pain-relieving effects of SCS returned after repositioning the electrode. According to this preliminary experience, SCS is effective for pain reduction in selected patients with chronic pain. Long-term follow-up is mandatory to evaluate the benefits and complications of SCS for relief of chronic pain.

Aged↗
PubMed1992

[Diversity of malaria in the Sahelo-Saharan region. A review apropos of the status in Niger, West Africa].

The concept of epidemiologic facies of malaria underlines the diversity in the expression of the disease in areas where important ecological variations interfere largely with transmission. Niger is quite a border region between the afrotropical fauna from the south and the Palearctic fauna from the north. The last one filters through the mountains where it maybe represents a relic of ancient paleoclimates. Annual variations of the northern limit of Anopheles arabiensis, in the Sahelo-Saharan region including some oasis, are related to temporary breeding places produced by seasonal rainfall, after estivation during the dry season or after a long migration with the wind. An. gambiae s.s is present in the south and along the Niger river, with An. funestus, even till Zinder. The northern limit of An. nili is the Niger river. The permanent variations of the environment induce great differences in the level of transmission between an intermediate stable situation in the south to an unstable one in the north. Epidemic outbreaks appear some years in vulnerable populations. The implementation of a malaria program supposes to take account of the various eco-epidemiologic situations all over the country. Even if mortality and morbidity became lower, natural precaution in some groups of people must be preserved.

Adolescent↗
PubMed1988

Reversible changes in stress fiber expression and cell shape in regenerating rat and rabbit aortic endothelium.

The influence of intimal de-endothelialization on stress fiber expression in regenerating rat and rabbit aortic endothelium was studied using immunofluorescence microscopy. Rat thoracic and abdominal aortae were balloon de-endothelialized, and endothelial cell shape and stress fiber expression was studied in both uninjured and de-endothelialized animals. In control animals, the majority of thoracic endothelial cells did not contain stress fibers while the majority of abdominal endothelial cells did. One week after injury, all the endothelial cells distal to the regenerating edge contained very prominent stress fibers. In areas directly adjacent to the still de-endothelialized surface, the endothelial cells had an intense, diffuse cytoplasmic staining without stress fibers. Regenerating endothelium also had a substantially higher length-to-width ratio, but smaller cell areas. Six weeks after injury, the endothelium had completely regenerated, and stress fibers were lost from the majority of the thoracic endothelial cells. Changes in abdominal aorta stress fiber expression were not as marked. In the rabbit, all the control thoracic endothelial cells had stress fibers; however, cells at the leading edge of a narrow region of de-endothelialization had few stress fibers. The results suggest that stress fibers do not play a primary role in cellular migration in situ. The transient increase in stress fiber expression in the rat may result from a temporary demand for greater adhesive capabilities until the subendothelial extracellular matrix is remodeled.

Animals↗
PubMed1977

Ovine fascioliasis following reinfection.

Sheep were reinfected with matacercariae once. Half were treated with anthelmintic one week before reinfection. Compared with a primary infection, the reinfecting flukes in most seemed to migrate faster through the liver although in one treated sheep migration seemed to be longer and more destructive. Migrations extended into areas little affected by the primary infection thus producing more widespread fibrosis. Although a temporary retardation in fluke growth rate occurred, there was no reduction in the numbers of flukes recovered. Flukes killed by anthelmintic formed large granulomata.

Animals↗
PubMed2006

Fracture and migration of a suprarenal inferior vena cava filter in a pregnant patient.

Placement of retrievable inferior vena cava (IVC) filters as prophylaxis for pulmonary embolism (PE) is an increasingly attractive option for patients who require temporary IVC filtration. However, experience thus far with retrievable filters in pregnant patients is limited. This report describes a suprarenally placed Recovery IVC filter in a pregnant woman with PE despite therapeutic anticoagulation. After failed induction of labor and uneventful cesarean section, the patient returned for filter retrieval 167 days after initial placement. Fracture and inferior migration of the filter was observed, and subsequent attempts at filter retrieval were unsuccessful.

Adult↗
PubMed1996

Anterior cervical discectomy with or without fusion with acrylate. A randomized trial.

STUDY DESIGN: A prospective randomized trial with assessment of treatment results by an independent observer and by patient questionnaire. OBJECTIVES: This study evaluated whether implantation of polymethylmethacrylate after anterior cervical discectomy improved clinical results and whether polymethylmethacrylate provided a solid bony union with preservation of anatomical relations of the cervical spine. SUMMARY OF BACKGROUND DATA: Discectomy without fusion disturbs anatomical relations of the cervical spine. Use of an autologous bone graft frequently causes donor-site complications. Therefore, synthetic materials such as polymethylmethacrylate have been used instead of bone to obtain spinal fusion. Whether these implants improve the clinical results of anterior discectomy is unknown. In addition, the radiological follow-up of discectomy with polymethylmethacrylate has hardly been investigated. METHODS: Between April, 1986, and April, 1990, all patients with radiologically proven cervical disc pathology and a radicular syndrome were eligible for this study. The primary endpoint of the study was the clinical result after 2 years. Assessment of the result was rated both by an independent observer using Odom's criteria and by the patient using a written questionnaire. Before surgery and during follow-up, radiographs were obtained. RESULTS: Two patients died during follow up. A good result was obtained in 28 of 42 patients (70%) treated with polymethylmethacrylate and in 30 of 39 patients (77%) of patients treated with discectomy only. Pre-operative neck pain subsided earlier if polymethylmethacrylate was used, but the difference was temporary and clinically insignificant. The use of polymethylmethacrylate resulted in a significant lower bony union rate. Polymethylmethacrylate frequently migrated into adjacent vertebrae. CONCLUSIONS: No relevant clinical differences between treatments were found. The radiological results of anterior discectomy with polymethylmethacrylate were inferior to those of discectomy only. Based on these results, the use of polymethylmethacrylate to obtain fusion after anterior discectomy is not recommended.

Acrylates↗
PubMed2006

Accidental dislocation of an intracaval temporary filter into the heart in a case of renal cell carcinoma extending into the vena cava.

In a case of renal cell carcinoma extending into the vena cava, a temporary intracaval filter was applied before surgery to prevent pulmonary artery thrombosis. Two days later, the filter accidentally migrated into the right ventricle during defecation. Fortunately, it was successfully removed without damaging cardiac musculature under fluoroscopy.

Carcinoma, Renal Cell↗
PubMed2005

Beta1 integrin as a xenoantigen in fetal porcine mesencephalic cells transplanted into the rat brain.

Xenografts of fetal porcine mesencephalic cells implanted into the rat striatum are generally rejected within several weeks. The fetal donor mesencephalon predominantly consists of neurons, but also contains microglial and endothelial cells, which are more immunogenic. In the present work, we investigated the occurrence of donor endothelial cells in grafts of porcine mesencephalic cells implanted into the rat striatum. Pig endothelial cells were monitored by immunochemical methods, using a monoclonal antibody (mAb) that recognizes a peptidic epitope of the porcine beta1 integrin, and isolectin IB4, for the staining of the Galalpha1,3Gal epitope. The analysis also involved the detection of the pig hyaluronate receptor CD44, and the cell adhesion molecule CD31. The anti-beta1 integrin mAb revealed endothelial-like cells in grafts of porcine mesencephalic cells as soon as 1 week after implantation. A similar staining pattern was obtained with the IB4 lectin. Unlike aortic endothelial cells, these pig brain-derived endothelial-like cells were not recognized by the anti-CD44 antibody. They also failed to express the CD31 adhesion molecule, a fact which suggests that they remained poorly mature, even in grafts maintained during 45 days in immunosuppressed rats. Interestingly, a strong expression of beta1 integrin immunoreactivity was noticed in a large proportion (80%) of the cells freshly dissociated from the fetal pig mesencephalic tissue. The immunoreactivity decreased progressively after transplantation of the cells into the rat brain. This observation suggests that dissociated neuroblasts are capable of a temporary expression of beta1 integrin. This molecule is known to participate in the process of cell sorting and migration in the developing brain. Hence, its expression could be the hallmark of a rescue mechanism triggered by the disruption of the cell/matrix interactions during the dissociation of the fetal mesencephalon. This disruption might account for part of the dramatic cell death process that occurs during the manipulation of the donor tissue.

Animals↗
PubMed1999

Treatment of a native right coronary artery with the PercuSurge Guardwire protection system during PTCA and stenting.

Cardiac catheterization in a patient with recent-onset unstable angina demonstrated a suboccluded dominant right coronary artery (RCA), with angiographic evidence of a large thrombus load and a severe focal stenosis of the left anterior descending (LAD) coronary artery. After abciximab, uneventful PTCA and stenting of the LAD was performed. The thrombus containing lesion of RCA was treated with balloon predilatation and stent deployment, and the whole procedure was accomplished with protection of the distal vessel by means of PercuSurge. This device was planned to avoid distal debris migration during percutaneous interventions of saphenous bypass grafts. The system is designed to allow the placement of a temporary occlusion device, a low-profile balloon, distal to the lesion to be treated during the procedure. The occlusive balloon is kept inflated during the treatment of the lesion. Before deflating the balloon and allowing blood to reach the distal vessel, whenever it is necessary, the material proximal to the balloon is aspirated through a monorail catheter. This aspiration removes blood and thrombi proximal to the occlusive balloon from the treated coronary artery. The case we present first reports the application of the device in a large native coronary artery, with an optimal distal flow restoring and no evidence of thrombus embolization. This type of protection of distal coronary vessels towards micro- and macroembolization of thrombi is a promising system of performing safer percutaneous interventions, even in acute ischemic syndromes.

Aged↗
PubMed1983

Transport of immune complexes from the subcapsular sinus to lymph node follicles on the surface of nonphagocytic cells, including cells with dendritic morphology.

The objective of the present study was to investigate the mechanism of antigen migration from the site of initial localization in the lymph node subcapsular sinus (SS) to regions of follicular retention in the cortex. The migration of horseradish peroxidase (HRP), used as a histochemically identifiable antigen, was followed by light and electron microscopy in C3H mouse popliteal lymph nodes obtained 1, 5, 15, and 30 min, and 5 and 24 hr after hindfoot pad injection of HRP. The observations showed that as early as 1 min after HRP injection, localization of antigen occurred at distinct sites in the SS and subjacent areas of the cortex on the afferent side. At these sites, between 1 min and 24 hr, the antigen formed light microscopically identifiable trails, which reached progressively deeper into the cortex with time toward individual follicular regions. By 24 hr this apparent migration of antigen was complete, and HRP was localized in follicles. This migration pattern did not occur on the efferent sides of lymph nodes, and it was dependent on the systemic presence of specific antibodies since it was observable only in passively immunized but not in nonimmune mice. Temporary retention of antigen by typical macrophages was also observed in the SS on the efferent side. This was minimal in nonimmune mice and was significantly enhanced in passively immunized mice. Electron microscopy indicated that the apparent migration of immune complexes was mediated by a group of cells observed in the migration path that had immune complexes sequestered on their surface or in plasma membrane infoldings. These antigen transporting cells (ATC) were relatively large nonphagocytic cells, with lobated or irregular euchromatic nuclei and cell processes of various complexity. ATC observed in or near the SS appeared to be less differentiated, were monocyte-like, and resembled non-Birbeck granule-containing Langerhans cell precursors or veiled cells. Others, located deeper in the cortex, appeared more differentiated, interdigitated with antigen-retaining dendritic cells, and shared morphologic characteristics with follicular dendritic cells (FDC). The results support the concepts that immune complexes are trapped in the SS and are transported by a group of non-phagocytic cells, other than lymphocytes, to follicular regions. The mechanism of transport may involve the migration of ATC with a concomitant maturation into FDC, or by a mechanism of ATC to FDC transport utilizing dendritic cell processes and membrane fluidity, or by a combination of the two mechanisms.

Animals↗