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At least 667 records · Page 37Linked to original sources
PubMed1996

Endovascular treatment of experimental aneurysms with liquid polymers: the protective potential of stents.

Liquid polymers have previously been used to treat experimental and human aneurysms. However, the delivery of a liquid embolic material into the cerebral circulation involves a high risk of irreversible vessel occlusion and stroke. To evaluate methods for the safe and effective treatment of experimental aneurysms with liquid polymer injection, we tested four different techniques to deliver cellulose acetate polymer (CAP) or N-hexyl-cyanoacrylate into canine side-wall carotid artery aneurysms. The animals were observed for 1 to 10 weeks after treatment. Two aneurysms were treated without protection of the distal circulation, one with CAP and another with N-hexyl-cyanoacrylate. In four cases, an angioplasty balloon was inflated within the parent artery during endosaccular injection of CAP. In two of these cases, the balloon was placed adjacent to the aneurysm orifice, resulting in simultaneous occlusion of both the aneurysm and the parent artery, and in the other two cases, the balloon was positioned proximal to the aneurysm, resulting in temporary flow arrest. Three aneurysms were treated with either CAP or N-hexyl-cyanoacrylate after implantation of a balloon-expandable tantalum stent within the parent artery across the aneurysm orifice. Complete angiographic obliteration was achieved in all but one case. One aneurysm ruptured. Another partially occluded aneurysm reopened 10 weeks after treatment. In all cases treated without stents, distal migration of the polymer resulted in either stenosis or occlusion of the parent arteries. The combination of stent implantation and polymer injection resulted in permanent aneurysm occlusion without detectable polymer migration. An intravascular stent deployed within the parent artery across the aneurysm orifice acted as a safety net during endosaccular polymer injection by allowing blood to flow from the aneurysm cavity while preventing distal migration of liquid polymer.

Aneurysm↗
PubMed1996

Failure to absorb: remigration by immigrants into Israel.

"Hypotheses about remigration by immigrants are investigated using longitudinal data from the 1970s for immigrants to Israel. The main finding is that experience of unemployment during the first year in Israel does not, on the whole, help predict subsequent remigration. The propensity to remigrate varies inversely with age for most groups, and it increases if the immigrant has not acquired permanent housing. Immigrants on temporary resident visas are naturally more prone to remigrate in the short run. The well-educated and the young are more likely to be temporary residents."

Age Factors↗
PubMed2005

Methane mass balance at three landfill sites: what is the efficiency of capture by gas collection systems?

Many developed countries have targeted landfill methane recovery among greenhouse gas mitigation strategies, since methane is the second most important greenhouse gas after carbon dioxide. Major questions remain with respect to actual methane production rates in field settings and the relative mass of methane that is recovered, emitted, oxidized by methanotrophic bacteria, laterally migrated, or temporarily stored within the landfill volume. This paper presents the results of extensive field campaigns at three landfill sites to elucidate the total methane balance and provide field measurements to quantify these pathways. We assessed the overall methane mass balance in field cells with a variety of designs, cover materials, and gas management strategies. Sites included different cell configurations, including temporary clay cover, final clay cover, geosynthetic clay liners, and geomembrane composite covers, and cells with and without gas collection systems. Methane emission rates ranged from -2.2 to >10,000 mg CH(4) m(-2) d(-1). Total methane oxidation rates ranged from 4% to 50% of the methane flux through the cover at sites with positive emissions. Oxidation of atmospheric methane was occurring in vegetated soils above a geomembrane. The results of these studies were used as the basis for guidelines by the French environment agency (ADEME) for default values for percent recovery: 35% for an operating cell with an active landfill gas (LFG) recovery system, 65% for a temporary covered cell with an active LFG recovery system, 85% for a cell with clay final cover and active LFG recovery, and 90% for a cell with a geomembrane final cover and active LFG recovery.

Air Pollutants↗
PubMedDate not supplied

Subcutaneously tethered temporary filter: pathologic effects in swine.

PURPOSE: To evaluate the histopathologic effects of the Tempo-filter, a temporary caval filter, on the caval wall and determine the feasibility of deployment and removal of the device in swine. MATERIALS AND METHODS: Filters were placed in the infrarenal inferior vena cava of 11 swine. The tethering catheter was sutured in a subcutaneous pocket near the puncture site. The original tethering catheter used in humans and a stiffer catheter designed to prevent migration in swine were evaluated. Postplacement, mid-study, and preexplant vena cavography procedures were performed. Four swine underwent in situ dissection at 3-10 weeks. Filters were removed from seven animals just before they were killed at 1-6 weeks. RESULTS: All filters were successfully placed. All seven filters were successfully removed at up to 6 weeks after placement. Cephalic migration of more than 1 cm was observed in 10 of 11 swine (100% of original catheters, 83% of stiff catheters). Other complications were more common with stiffer tethering catheters, including caval stenosis in 40% of original catheters and 100% of stiff catheters, filter cone thrombus in 0% and 67%, tethering catheter thrombus in 20% and 83%, pulmonary embolism in 0% and 50%, and death in 0% and 17%, respectively. There was mild vessel wall damage in the vena cava. CONCLUSION: Placement of the Tempofilter and removal at up to 6 weeks after placement is feasible.

Animals↗
PubMedDate not supplied

Percutaneous endoscopic gastrojejunostomy: a dual center safety and efficacy trial.

Although jejunal tube placement through a percutaneous endoscopic gastrostomy (PEG) has not been proven to be preferable to PEG feeding, it would be theoretically advantageous for those patients prone to gastrointestinal aspiration. However, reliable placement of a small bowel feeding tube through a PEG has been technically difficult. We have previously reported successful placement of a percutaneous endoscopic gastrojejunostomy (PEG/J) with minimal complications. These results are in contrast to other series that report technical difficulty, frequent tube dysfunction and gastric aspiration. We describe an over-the-wire PEG/J technique performed by multiple operators at two medical centers. Gastrostomy tube placement was successful in 94% of patients. Initial placement of the jejunal tube was successful in 88% of patients. Second attempts were 100% successful. The average procedure time was 36 minutes. The distal duodenal and jejunal placement of the jejunal tube resulted in no episodes of gastroduodenal reflux. Complications included jejunal tube migration (6%), clogging (18%), and unintentional removal (11%). The majority of patients were ultimately converted to either oral or intragastric feedings. We conclude that the PEG/J system is a reliable, reproducible method of small bowel feeding and is associated with no episodes of tube feeding reflux when the jejunal tube is positioned in the distal duodenum or beyond. Furthermore, it provides a temporary nutritional bridge for those patients who are later transitioned to either PEG or oral feeding.

Adult↗
PubMed1997

Effect of Escherichia coli L-form cytoplasmic membranes on the interaction between macrophages and Lewis lung carcinoma cells: scanning electron microscopy.

Scanning electron microscopy (SEM) investigations on the interactions between peritoneal macrophages from Lewis lung carcinoma (LLC)-bearing mice and LLC tumour cells during 21 days after tumour implantation were carried out. The action of lipopolysaccharide (LPS)-containing cytoplasmic membranes (CM), from the stable protoplast type L-form of Escherichia coli, on the activity of in vitro phagocytosis was studied; CM induced a continuous increase in macrophage numbers. Activation of macrophage surfaces in healthy and tumour-bearing mice was established. Lamelipods, pseudopods and migration fringes 14 days after CM application were seen. Crater-like cavities deeply in the macrophage cells as well as adherent or prominent engulfed tumour cells within macrophages were observed during in vitro interaction with LLC cells. Macrophages from tumour-bearing mice without CM treatment showed less activation evaluated by SEM during earlier stages of tumour growth. The SEM investigation proved the temporary stimulating effect of E. coli L-form CM on the cell surface activation of peritoneal macrophages in healthy and LLC-bearing mice.

Animals↗
PubMed1978

White cell involvement in the inflammatory, wound healing, and immune actions of vitamin A.

Stress or injury-induced phenomena, such as impaired wound healing and immune depression, may be related to impaired function of certain leukocyte populations. Since vitamin A prevents some aspects of stress, we studied its effect on various white cell populations in normal and injured rats. Supplemental vitamin A (150,000 IU/kg chow) to normal rats resulted in marked increases in thymic weight and lymphocytes without any effct on adrenal weight. The basal chow contains 13,700 IU vitamin A per kg. In rats subjected to moderately severe injury (dorsal wounding or unilateral femoral fracture), supplemental vitamin A greatly diminished the thymic involution observed in chow-fed controls and delayed or minimized the accompanying adrenal hypertrophy. In uninjured rats, supplemental vitamin A induced in three to four days a temporary circulatory leukocytosis characterized by lymhocytosis, monocytosis, and a relative neutropenia. These changes in the blood picture persisted one day after femoral fracture. On the second and third day postfracture the lymphocyte and neutrophil values returned to normal while the monocytosis persisted. Polyvinyl alcohol sponges implanted next to the fracture site demonstrated that supplemental vitamin A consistently increased the number of white blood cells migrating into the wound area and showed significantly larger numbers of monocytes/macrophages. These data suggest that vitamin A influences the numbers and nature of white cells involved in immune, inflammatory, and wound healing processes. In addition to the known antiglucocorticoid activity of vitamin A, these effects may represent a direct beneficial action of dietary vitamin A supplements for stressed and injured animals.

Adrenal Glands↗
PubMed2006

Removal of retrievable self-expandable urethral stents: experience in 58 stents.

The purpose of this study was to retrospectively evaluate the safety and efficacy of removing retrievable self-expandable urethral stents using a retrieval hook wire. Under fluoroscopic guidance, the removal of 58 polyurethane or PTFE (polytetrafluoroethylene)-covered stents was attempted in 33 patients using a retrieval hook wire. Indications for removal were elective removal (n = 21), stent migration (n = 19), formation of tissue hyperplasia around or inside of the stent (n = 14), stent deformity (n = 3), and severe pain (n = 1). The mean time the stents remained in place was 64.8 +/- 42.9 days (range, 1-177 days). Fifty-six (97%) of the 58 stents were successfully removed using the retrieval hook wire despite the following difficulties; hook wire disconnection (n = 2), untied drawstrings (n = 3), and polyurethane membrane disruption/separation (n = 4). The removal procedure using a retrieval hook wire failed in two stents (3%) which had migrated into the urinary bladder. One of the two stents with migration into the urinary bladder was removed using a snare through the cystostomy route. The overall complication rate was 14% (seven hematuria cases and one urethral tear case), and all were minor and spontaneously resolved without further treatment. In conclusion, removal of retrievable urethral stents using a retrieval hook wire was safe and effective despite some technical difficulties. It is a useful method for allowing temporary stent placement and solving various complications of stent use.

Adult↗
PubMed2000

Adjustable gastric banding: 5-year experience.

BACKGROUND: From 1993 to 1999, 172 patients underwent adjustable silicone gastric banding (ASGB) or laparoscopic adjustable silicone gastric banding (LASGB). In 109 patients the adjustable band was placed via laparoscopy; in the other patients it was placed via laparotomy (prelaparoscopic era, conversions from other bariatric operations, conversions for laparoscopic failure). The conversion rate from laparoscopy to laparotomy was 9.3%, occurring in the early part of our experience. METHODS: Mean age was 37.9 years, weight 135 +/- 14.8 kg (82-218) and BMI 46.3 +/- 5.4 (35.1-69.5). All patients had multiple band adjustments, temporary antisecretive, electrolyte and vitamin therapy, and follow-up per routine. RESULTS: Weight loss at 3 years was 30.2%; mean percent loss of excess weight was 62.5%. There was no mortality. The most important technical complications were: gastric pouch dilatation that required band replacement or removal (5.8 %); mild gastric pouch dilatation reversible with adequate dietary and pharmacological treatment (4.6%); intraoperative gastric perforation (2.3%); band migration (0.6%). The band was removed in 2.3%, with conversion to another bariatric procedure in 1.1%. CONCLUSIONS: Results have been satisfactory thus far.

Adolescent↗
PubMed1991

[Treatment of furcation involvement--implantation of alloplastic materials].

Based on the results of clinical and experimental research, the treatment of furcation-involved teeth by alloplastic implant is critically evaluated. Only materials like calcium phosphate ceramic have shown to be of therapeutic value. Clinically it was found in reentry surgeries 6 months after implantation that the vertical and horizontal components of grade II furcation-involved mandibular molars were reduced to a greater extent with hydroxyapatite implants compared to flap surgery alone. Histological studies in animals were performed only in periodontal infrabony defects; these data yielded contradictory results. However, most studies showed that the apical migration of the epithelium along the root surface was reduced and periodontal regeneration was enhanced. Because these results cannot be extrapolated to the specific situation in the furcation area, the routine treatment of furcation-involved teeth with alloplastic implants is not recommended. Possible future aspects of this treatment modality may involve a combination of the membrane technique with alloplastic implants as well as a temporary closure of the involved furcation entrance with a sterile bone cement. These techniques are based on the principle of guided tissue regeneration. Both treatment modalities demonstrate promising results.

Alveolar Bone Loss↗
PubMedDate not supplied

Cellular and humoral components of neutrophil chemotaxis in neonates with bacterial infection.

The initial stage of infection is characterized by both, changes in leucocyte function and humoral factors activity. In this paper we evaluated random migration and chemotaxis of neutrophils and serum ability to generate humoral factors influencing the neutrophil function. The studies were performed in 51 neonates during the acute phase of bacterial infection and in the remission time. Both random migration and chemotaxis were decreased during the acute phase of disease and normalized during remission. The same was true for serum ability to generate chemotactic activity. The serum of sick neonates did not alter the mobility of neutrophils isolated from adult healthy donors and it did not influence the normal chemotactic activity. We conclude, that the handicapped locomotive abilities of neutrophils in bacterial infection are temporary, and may require in severely ill infants supportive therapy to maintain adequate cellular and humoral immunity.

Bacterial Infections↗
PubMed1984

Psoriasis: a defect in the regulation of epidermal proteases, as shown by serial biopsies after cantharidin application.

The possible role of epidermal serine proteases in the genesis of psoriatic lesions was investigated by sequential biopsies of the epidermal damage induced by topical cantharidin. In the skin of normal subjects, epidermal damage was followed by the transient appearance of proteolytic activity in the upper epidermis accompanied by temporary hyperacanthosis and perivascular inflammatory cells in the superficial dermis. In the uninvolved skin of five patients with psoriasis this proteolysis persisted longer, for more than 7 days. Thereafter, in three of the patients, the proteolysis abated, and this was followed by disappearance of the hyperacanthosis and the dermal infiltrate; in the other two psoriatics the proteolysis and hyperacanthosis increased, and a typical Koebner phenomenon ensued. Migration of neutrophils into the epidermis occurred as a later event. Thus the abnormal persistence of proteolytic activity in the upper epidermis after cantharidin application distinguishes the normal from the psoriatic skin injury response and might initiate the psoriatic lesion.

Cantharidin↗
PubMed2004

Population biology of the invasive freshwater snail Physa acuta approached through genetic markers, ecological characterization and demography.

Abstract The respective role of factors acting on population functioning can be inferred from a variety of approaches, including population genetics and demography. We here investigated the role of four of these factors (mating systems, population size, bottlenecks and migration) in the hermaphroditic freshwater snail Physa acuta. Twenty-four populations were sampled either around Montpellier (local scale), or at the scale of France (global scale). At local scale, eight populations were sampled twice, before and after summer drying out. The genetic structure of these populations was studied using microsatellite loci. Populations were classified according to openness (ponds vs. rivers) and water regime (permanent vs. temporary) allowing predictions on genetic patterns (e.g. diversity within populations and differentiation). At local scale, progeny-arrays analysis of the selfing rate was conducted, and size distributions of individuals were followed over two years. Results with regard to the four factors mentioned above were: (i) Estimates of population selfing rates derived from inbreeding coefficients were only slightly higher than those from progeny-arrays. (ii) More variation was detected in rivers than in ponds, but no influence of water regime was detected. One reason might be that permanent populations are not going less often through low densities than those from temporary habitats at the time scale studied. (iii) There was limited evidence for genetic bottlenecks which is compatible with the fact that even marked reduction in water availability was not necessarily associated with demographic bottlenecks. More generally, bottlenecks reducing genetic variation probably occur at population foundation. (iv) Lower genetic differentiation was detected among rivers than among ponds which might be related to limitations on gene flow. Demographic and temporal genetic data further indicates that flooding in rivers is unlikely to induce marked gene flow explaining the strong genetic differentiation at short geographical scale in such habitats. Finally, the demographic data suggest that some populations are transitory and subject to recurrent recolonization, a pattern that was also detected through genetic data.

Animals↗
PubMedDate not supplied

[Kinematics of fibroblast spreading. II. Individual locomotor activity].

An analysis of area changes of normal mouse fibroblasts during their spreading is made with time intervals of 5-50 s. A mean increase of the area takes place simultaneously with area fluctuations of various rhythms, which result from accidental undulations of the lamella edge. The fluctuations are also the same during intermediate temporary stopping of cell spreading. The central cell region--endoplasm--is stretched passively by centrifugal lamella forces and is an active antagonist of forces in squeeze processes. A description is made of the lamella edge undulations like the phase states change of protraction and retraction, and it is shown by two-dimensional phase diagrams that edge-activity has a zone organisation. These zones can migrate upon the cell perimeter as a wave in stohastic excitable medium.

Animals↗
PubMed1985

The biliary tract in patients with acute gallstone pancreatitis.

The biliary tract has been prospectively studied in a consecutive series of 769 patients undergoing surgery for gallstones to determine whether differences exist between subjects with and without a history of acute pancreatitis. The incidence of acute gallstone pancreatitis (AGP) was 7.7 per cent and men with gallstones were significantly more likely to develop pancreatic inflammation. Operations on patients with AGP were accompanied by a higher mortality rate which was almost entirely due to the severity of the disease at the time of surgery. The earlier operations were performed after the onset of pancreatitis the more often stones were found in the common bile duct and at the ampulla. Patients with AGP had smaller and more numerous gallbladder stones in association with a wider cystic duct that controls. The common bile duct diameter in patients with AGP was independent of the presence of choledochal calculi implying either previous temporary obstruction to the biliary tree or a dilated duct ab initio. Pancreatic duct reflux was far more commonly observed on the cholangiograms of patients with AGP and in these patients reflux occurred into a wider pancreatic duct, at a greater angle and was associated with a longer functioning common channel. No patient developed recurrent pancreatitis following biliary surgery. These features strongly support the concept of gallstone migration and suggest that patients with gallstones who develop acute pancreatitis have essential differences in their biliary tree which mechanically facilitate migration of calculi.

Acute Disease↗
PubMed2004

Shape retaining injectable hydrogels for minimally invasive bulking.

PURPOSE: Particle migration, poor shape definition and/or rapid resorption limit the success of current urethral bulking agents. We propose that shape defining porous scaffolds that allow cell infiltration and anchoring, and may be delivered in a minimally invasive manner may provide many advantageous features. MATERIALS AND METHODS: Alginate hydrogels were prepared with varying degrees of covalent cross-linking and different pore characteristics. Dehydrated scaffolds were compressed into smaller, temporary forms, introduced into the dorsal subcutaneous space of CD-1 mice by minimally invasive delivery through a 10 gauge angiocatheter and rehydrated in situ with a saline solution delivered through the same catheter. Ionically cross-linked calcium alginate gel served as a control. Specimens were harvested at 2, 6, 12 and 24 weeks to evaluate implant shape retention and volume, cell infiltration and calcification, and the presence of an inflammatory response. RESULTS: A total of 90 scaffolds were implanted and 95% were recovered at the site of injection. All of these scaffolds successfully rehydrated and 80% recovered and maintained their original 3-dimensional shape for 6 months. Scaffold volume and tissue infiltration varied depending on the degree of alginate cross-linking. Highly cross-linked materials (20% and 35%) demonstrated the best volume maintenance with the latter facilitating the most tissue infiltration. The inflammatory response was minimal except with the 80% cross-linked material. Calcification was not observed in covalently cross-linked scaffolds. In contrast, 98% of calcium alginate implants were calcified. CONCLUSIONS: Shape retaining porous hydrogels meet many of the requirements necessary for a successful injectable bulking agent and offer advantages over currently used agents.

Alginates↗
PubMed1975

Seasonal population densities of snails transmitting urinary and intestinal schistosomiasis in Lusaka, Zambia.

The two molluscan intermediate hosts of S. haematobium schistosomiasis: Bulinus africanus and Bulinus globosus, were found most commonly in habitats that retained water for a substantial part of the year rather than in temporary rain-filled pools. Biomphalaria pfeifferi which transmits S. mansoni were found principally in streams and impoundments like dams but scarce in rivers. In a permanent habitat, the peak density of snails was between the warm, dry months of August and September while in a temporary habitat B. (Physopsis) sp. were most abundant towards the end of the rainy season in March and April. The influence of rainfall and the prevailing the temperature on the fluctuations in the density of snails populations is considered. Further, the low infection rate in snails found in the field is discussed in relation to the critical effect of temperature on this feature. The problem of increasing migration of rural inhabitants to the peri-urban areas and the possible escalation of prevalence rates is considered in relation to the control measures that may be instituted in view of the substantial body of base-line data now available to effect focal control.

Animals↗