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At least 541 records · Page 30Linked to original sources
PubMed1991

Cultured epidermal allografts as biological wound dressings.

Recent advances in cell culture technology permit the generation of large stratified epithelial sheets appropriate for wound coverage. Autografts (sheets prepared from the patient's own skin) have proven life-saving in the treatment of large third-degree burns and have been successfully employed in the management of chronic ulcers. Allografts (sheets prepared from the skin of an unrelated donor) have also been used. In our experience, cultured allografts derived from neonatal foreskin provide a potent stimulus to healing in a variety of partial thickness wounds. Their application is a simple outpatient procedure which involves no discomfort for the patient. In contrast to autografting, no biopsy is necessary and use of cultured allogenic cells permits immediate grafts availability and possibility of stockpiling and preserving grafts for future use. Preparation of epithelial sheets suitable for grafting is also faster and easier with newborn than with adult donor cells. Newborn allografts have caused rapid healing of most previously refractory ulcers with long-term results comparable to those obtained with conventional split thickness grafting. We postulate that cultured allografts act by providing a temporary wound covering while releasing multiple cytokines that synergistically promote permanent reepitheliazation by previously quiescent host keratinocytes then stimulated to divide and migrate. Whether allografts are immunologically rejected in a clinically undetectable reaction or simply replaced stochastically by host keratinocytes is presently unknown.

Biological Dressings↗
PubMed2003

The maintenance of reproductive isolation in a mosaic hybrid zone between the fire-bellied toads Bombina bombina and B. variegata.

Mosaic hybrid zones arise when ecologically differentiated taxa hybridize across a network of habitat patches. Frequent interbreeding across a small-scale patchwork can erode species differences that might have been preserved in a clinal hybrid zone. In particular, the rapid breakdown of neutral divergence sets an upper limit to the time for which differences at marker loci can persist. We present here a case study of a mosaic hybrid zone between the fire-bellied toads Bombina bombina and B. variegata (Anura: Discoglossidae) near Apahida in Romania. In our 20 x 20 km study area, we detected no evidence of a clinal transition but found a strong association between aquatic habitat and mean allele frequencies at four molecular markers. In particular, pure populations of B. bombina in ponds appear to cause massive introgression into the surrounding B. variegata gene pool found in temporary aquatic sites. Nevertheless, the genetic structure of these hybrid populations was remarkably similar to those of a previously studied transect near Pescenica (Croatia), which had both clinal and mosaic features: estimates of heterozygote deficit and linkage disequilibrium in each country are similar. In Apahida, the observed strong linkage disequilibria should stem from an imperfect habitat preference that guides most (but not all) adults into the habitats to which they are adapted. In the absence of a clinal structure, the inferred migration rate between habitats implies that associations between selected loci and neutral markers should break down rapidly. Although plausible selection strengths can maintain differentiation at those loci adapting the toads to either permanent or temporary breeding sites, the divergence at neutral markers must be transient. The hybrid zone may be approaching a state in which the gene pools are homogenized at all but the selected loci, not dissimilar from an early stage of sympatric divergence.

Animal Migration↗
PubMed1986

Red krypton and blue-green argon panretinal laser photocoagulation for proliferative diabetic retinopathy: a laboratory and clinical comparison.

The effects of PRP with red krypton laser are essentially identical to those produced with blue-green argon laser. Burns of the rabbit retina produced with these two different lasers are almost the same. In a prospective and randomized clinical trial of proliferative diabetic retinopathy treatment there was no significant difference between PRP using these two different lasers. The characteristic changes of rabbit fundi 3, 7, and 30 days after PRP with red krypton laser were almost the same as those following blue-green argon laser. Both types of treatment frequently produced small vitreous hemorrhages and exudative retinal detachments, but choroidal thickening occurred more frequently with argon treatment. These changes were transient and had resolved within 30 days of treatment. The microscopic changes consisted of pigment epithelial disruption with pigment migration into the retina, heat coagulation of the photoreceptors, disruption of the outer and inner nuclear layers with atrophy of the nuclei, and temporary swelling of the nerve fiber layer. The untreated retina and choroid between burns was not involved and appeared normal at each period. Thirty days after treatment, the scarring produced by these two types of burns was identical. Seventy-one eyes with proliferative diabetic retinopathy having three or four retinopathy risk factors were treated with panretinal laser photocoagulation, and followed in a prospective study for 6 months. Thirty-six eyes were randomly selected for blue-green argon treatment, and 35 were randomly selected for red krypton treatment. The incidence of undesired side effects during the first 2 weeks following treatment was almost identical between the two groups. However, by 1 month the majority of eyes in both groups had visual acuities equal to or better than the pretreatment acuities and complete regression of NVD. Six months after treatment, the majority of eyes in both groups continued to have visual acuities equal to or better than the pretreatment acuities with fewer cases having larger losses of vision in the krypton treated group. Loss of peripheral visual field was equal with the two types of treatment having a minimal decrease with the IV-4e isopter, but substantial loss with the I-4e isopter. Additional vitreous hemorrhage rarely occurred in either group, but was slightly more frequent in those treated with krypton. Complete regression was accomplished in most eyes with pretreatment disc and/or NVE in both groups, but persistence of neovascularization was more frequent in those treated with krypton. Overall, the wavelength used seemingly had little effect on the result.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed2006

Minimally invasive keyhole approach for removal of a migratory balloon complicated by endovascular embolization of a carotid-cavernous fistula.

PURPOSE: This report presents our experience in using a minimally invasive keyhole approach to remove a migratory balloon in the cerebral artery in one patient. CASE REPORT: A 19-year-old male suffered from carotid-cavernous fistula after craniofacial trauma two months previously. The patient received endovascular embolization of a carotid-cavernous fistula with detachable balloons. Unfortunately, migration of one balloon to the right middle cerebral artery (MCA) at the M1-M2 junction was noted after detaching the balloon during this procedure. Volume expansion, anticoagulation therapy and an emergency pterional keyhole approach with removal of the displaced balloon were performed successfully. Transient left hemiparesis due to temporary occlusion of the right middle cerebral artery by the balloon was promptly alleviated. There was no definite neurological sequel after the operation. CONCLUSIONS: Although detachable balloon embolization is the best initial treatment of direct carotid-cavernous fistulas, it is likely to migrate to downstream cerebral arteries. We recommend a minimally invasive pterional keyhole approach as a good alternative for treating such endovascular complications to improve outcome.

Adult↗
PubMed2002

Dysphagia and quality of life after laparoscopic Nissen fundoplication in patients with and without prosthetic reinforcement of the hiatal crura.

BACKGROUND: Recurrent hiatal hernia with or without intrathoracic wrap migration ("slipping Nissen") is one of the most common complications after laparoscopic Nissen fundoplication (LNF). Therefore, we decided to reinforce the hiatal crura using a prosthetic mesh prosthesis in an attempt to reduce recurrent hiatal hernia. METHODS: The current nonrandomized study compares the surgical outcome, including quality of life data [Gastrointestinal Quality of Life Index (GIQLI)] and subjective degree of dysphagia, in a total of 200 patients with (n = 100) or without (n = 100) mesh prosthesis for a follow-up for at least 1 year. RESULTS: There are no significant differences between groups in postoperative DeMeester score or lower esophageal sphincter pressure. In the group without mesh prosthesis, in 6 cases laparoscopic redo surgery was necessary due to severe and persistent dysphagia (n = 2) or a slipping Nissen (n = 4). Additionally, in 5 patients we found recurrent hiatal hernia, but patients have been without symptoms for at least 1 year. In the group with mesh prosthesis, laparoscopic refund application was performed in only 1 patient due to a slipping Nissen. In this group, recurrent hiatal hernia was not found in endoscopy. After laparoscopic antireflux surgery, GIQLI showed an equal improvement in both groups with an outcome comparable to that for healthy individuals. Postoperative dysphagia was significantly higher in the group with mesh prothesis within the 3 first months after surgery. One year after surgery no differences could be found. CONCLUSIONS: Our findings suggest that LNF with reinforcement of the hiatal crura reduces the risk of recurrent hiatal hernia with or without wrap migration. In addition, LNF with mesh prosthesis improves patient's quality of life significantly to the same level as that in patients without mesh prosthesis. Postoperative dysphagia is higher in the early period after surgery, but this is only temporary. Long-term results of a randomized trial must be obtained before a general standardization can be discussed.

Deglutition Disorders↗
PubMed1955

Studies on the pathogenesis of acute inflammation. I. The inflammatory reaction to thermal injury as observed in the rabbit ear chamber.

A special adaptation of the rabbit ear chamber has been devised to study in vivo, under high magnification, the acute inflammatory reaction to thermal injury. Systematic observations of the cellular response have led to the following conclusions. 1. Contrary to the commonly accepted view, vasodilatation does not always precede the adherence of leucocytes to vascular endothelium. 2. The fact that leucocytes often adhere to one another as well as to the endothelium indicates that the increased adhesiveness characteristic of the early stages of inflammation is not limited to the surfaces of the endothelial cells. 3. The sharing of erythrocytes and platelets in this increased stickiness suggests that a "plasma factor" is involved. There is indirect but as yet inconclusive evidence that the plasma factor may concern the clotting mechanism of the blood. 4. The adherence of leucocytes to the endothelium is usually first noted on the side of the vessel closest to the site of injury. This previously undescribed phenomenon of "unilateral sticking" is in keeping with the concept that the vascular reaction is caused by products of cellular damage which diffuse to the vessel from the site of injury. 5. Leucocytes always become adherent to the endothelium before penetrating the vessel wall. They often migrate about for some time on the endothelial surface before undergoing diapedesis. 6. Although no definite stomata are at any time visible in the endothelium, penetrating leucocytes may leave behind temporary defects through which other leucocytes and even erythrocytes may pass. 7. The diapedesis of leucocytes appears to depend primarily upon cellular motility. It may occur in static vessels where there is presumably little if any hydrostatic pressure. 8. The diapedesis of erythrocytes, on the other hand, is a passive process depending upon intravascular pressure. Its occurrence is greatly exaggerated in areas in which intravascular pressure becomes elevated. Such elevations occur as the result of proximal arteriolar dilatation and distal occlusion of vessels. 9. Once they have reached the extravascular tissues the leucocytes move about more or less at random, apparently uninfluenced by any compelling chemotactic force. Their resultant migration, however, is toward the site of injury around which they eventually tend to congregate. 10. The histiocytes normally present in the connective tissue appear to play no role in the type of acute inflammatory reaction produced in these experiments.

Animals↗
PubMed1993

Effect of shear stress upon localization of the Golgi apparatus and microtubule organizing center in isolated cultured endothelial cells.

Despite substantial evidence to suggest that directed cell migration is dependent upon positioning of the Golgi apparatus (GA) and the microtubule organizing center (MTOC), some controversy exists about whether such a relationship is relevant to endothelial cells under flow. The present study was undertaken to provide an indepth investigation of the relationship between shear stress, GA/MTOC localization, cell migration and nuclear position. Bovine carotid endothelial cells were exposed to 22 or 88 dynes/cm2 for 0.5, 2, 8 or 24 h, and localization of their GA/MTOCs was determined relative to the direction of flow. In no-flow control specimens, (0, 0.5, 2, 8 and 24 h) there was no change in the equally distributed GA/MTOCs. In contrast, during the first 8 h at 88 dynes/cm2 and by 2 h at 22 dynes/cm2 there was a significant increase in the number of cells with GA/MTOCs localized upstream to flow direction. The effect was temporary, however, and by 24 h there was no significant difference between the no-flow, 22 and 88 dynes/cm2 specimens. Analysis of GA/MTOC localization with respect to the direction of cell migration determined that 72.5% of no-flow cells possessed GA/MTOCs localized to the sides of nuclei nearest the direction of migration. In contrast, 64% of the specimens shear stressed over the same time period had GA/MTOCs localized to the sides of nuclei opposite the direction of migration. These results suggest that positioning of the GA/MTOC in endothelial cells is not dependent completely upon the direction of migration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Observations on the migratory behaviour of Schwann cells from adult peripheral nerve explant cultures.

The migration of Schwann cells from adult sciatic nerve explant cultures has been examined by time-lapse photomicrography. Analysis of Schwann cell migratory behaviour indicates that the initial outwandering by individual Schwann cells was random. Although chance cell-cell contacts resulted in temporary immobilization of pairs of cells, stable multicellular structures did not form during this initial phase. As local cell densities increased, Schwann cells assembled networks within which Schwann cell movement continued to be observed. A second form of Schwann cell outgrowth was observed from degenerating fibres in which arrays of highly oriented Schwann cells migrated away from their basal lamina tubes onto the culture dish. These observations of Schwann cell random migration, network self-assembly and coordinated extratubal migration are considered to highlight aspects of Schwann cell behaviour, independent of axonal influences, which may have relevance to their role in peripheral nerve repair following nerve section.

Animals↗
PubMed1985

Experimental evidence for a proteinaceous presegmental wave required for morphogenesis of axolotl mesoderm.

Mesoderm of axolotl embryos at various developmental stages was briefly exposed to a calcium-free 0.01% trypsin solution by temporary removal of the epidermis. This treatment was found to disrupt somite segmentation in a localized region and the pronephric duct was unable to migrate through this region. The affected area, consisting of 3.91 +/- 1.04 somites, traveled through the embryo in synchrony with, and 3.55 +/- 0.69-somite widths ahead of segmentation. Trypsinization in the presence of 340 microM calcium resulted in normal duct migration while somite segmentation was still affected. These results demonstrate the existence of a trypsin-sensitive region in the somitic mesoderm and the lateral mesoderm of the duct path that travels in advance of somite segmentation and in synchrony with it. In addition, the trypsin sensitivity of the duct path is calcium dependent whereas that of the somitic mesoderm is not.

Ambystoma↗
PubMed1989

Remittances from labor migration: evaluations, performance and implications.

2 evaluative views of worker remittances draw opposite conclusions. The negative one posits that remittances increase dependency, contribute to economic and political stability and development distortion, and lead to economic decline that overshadows a temporary advantage for a fortunate few. The positive view sees remittances as an effective response to market forces, providing a transition to an otherwise unsustainable development. They improve income distribution and quality of life beyond what other available development resources could deliver. The implications are tested for labor supply countries to Europe and the Middle East. The implications of the negative are not supported. Although the dire predictions of the pessimistic view have not materialized, the converse - contributions of remittances to economic performance - should not be overstated due to a lack of data.

Africa↗
PubMed1997

Can a brain drain be good for growth in the source economy?

"This paper analyzes the interaction between income distribution, human capital accumulation and migration. It shows that when migration is not a certainty, a brain drain may increase average productivity and equality in the source economy even though average productivity is a positive function of past average levels of human capital in an economy. It is also shown how the temporary possibility of emigration may permanently increase the average level of productivity of an economy."

Demography↗
PubMed1988

Functional modification of a 21-kilodalton G protein when ADP-ribosylated by exoenzyme C3 of Clostridium botulinum.

Exoenzyme C3 from Clostridium botulinum types C and D specifically ADP-ribosylated a 21-kilodalton cellular protein, p21.bot. Guanyl nucleotides protected the substrate against denaturation, which implies that p21.bot is a G protein. When introduced into the interior of cells, purified exoenzyme C3 ADP-ribosylated intracellular p21.bot and changed its function. NIH 3T3, PC12, and other cells rapidly underwent temporary morphological alterations that were in certain respects similar to those seen after microinjection of cloned ras proteins. When injected into Xenopus oocytes, C3 induced migration of germinal vesicles and potentiated the cholera toxin-sensitive augmentation of germinal vesicle breakdown by progesterone, also as caused by ras proteins. Nevertheless, p21.bot was immunologically distinct from p21ras.

ADP Ribose Transferases↗
PubMed2000

[Intramedullary fixation within bones of the hand: 20 years of experience].

Intramedullary fixation within bones of the hand has been used for treatment of 313 fractures in 169 patients after serious trauma or replantation between 1978 and 1998. Kirschner wires or Steinmann pins were introduced at the fracture site and anchored within both metaphyses. The method was used in various types of fractures, comminuted ones and bone defects included. In all cases fracture healed between 4 and 8 weeks. No deep infection occurred, in 2 patients the implants had to be removed because of their migration. The method is technically undemanding and allows for immediate postoperative rehabilitation. Total range of motion exceeded by 15% results achieved in patients treated with temporary immobilization of the hand.

Adolescent↗
PubMed2003

[Self-expanding stent in obstructing colorectal cancer. A new technique to avoid abdominal surgery].

Emergency operations for obstructing colorectal cancer are associated with high morbidity and mortality rates and often result in a temporary or permanent colostomy. A colorectal stent can be used both for palliation and as a "bridge to surgery". Twenty-three patients with obstructive sigmoid or rectal cancer were selected for stenting. Self-expanding metal mesh stents were placed under endoscopic and flouroscopic guidance. Stent placement was technically successful in 19 patients and clinical success was seen in 18. There were only three minor complications, no major and no procedure related mortality. Four patients were later resected without a diverting stoma, two with rectal cancer had preoperative MRI and radiotherapy. In 15 patients the procedure was regarded as palliative. Stent migration was noted in four patients but symptomatic reobstruction did not occur, no patient needed later surgery. Colorectal stenting procedure is effective and safe and can be used in obstructing cancers both as a temporary relief before elective resection and as a definitive treatment in palliative cases.

Aged↗
PubMed1984

[Abdominal complications of ventriculo-peritoneal shunts in children. 65 cases].

From 1971 to 1982, among 1 200 children with hydrocephalus cured by ventriculo-peritoneal shunt, 65 have presented an abdominal complication. Some of them are rare and easily explainable: 2 intra-operative viscus perforations, 1 intestinal obstruction, 3 extrusions of the catheter into an inguinal hernia. Also rare, C.S.F. ascites (5 cases) et C.S.F. pseudocysts (3 cases) presented with typical symptomatology easily diagnosed, but their etiology is not clear. The main complications are peritonitis without perforation (32 cases) and migrations of the catheter in the colon (19 cases): their etiology is an intra-operative bacterial contamination, they happen during the following weeks or months after the shunt procedure. They are associated with 8 among 9 deaths of our data by gram negative germ meningitis. Removal of the peritoneal catheter and temporary external shunt are their main treatment.

Ascites↗
PubMed1988

Resolution No. 2478/87-DM setting forth requirements to grant an entry permit or residency of a permanent or temporary nature, 15 September 1987.

This Resolution of Argentina sets forth the following categories of persons as those who may be granted an entry permit or residency of a permanent or temporary nature under Decree 1434/87: 1) professionals, technicians, or specialized personnel whose admission is required to undertake their specialized duties for businesses, or persons whose solvency or economic or social activity is publicly recognized; 2) business persons, artists, or athletes contracted by a person of known solvency to undertake their specialized duties; 3) scientists, professors, writers, journalists, or persons of special importance to the cultural, social, or political order; 4) students who, according to the laws of their own country, have reached the age of majority; 5) religious persons belonging to recognized religions; 6) foreigners who are of special interest to the country because of their talents or personal circumstances; 7) immigrants who have sufficient capital to undertake a commercial, industrial agricultural, mining, or fishing activity; persons who deposit US $30,000 for not less than 120 days are considered to have sufficient capital; 8) parents, unmarried children, or spouses of Argentine citizens, foreigners resident temporarily and permanently in Argentina, or persons mentioned in 1) to 7) above. Under Resolution 700/88-DNM (National Director of Migration) of 3 March 1988, foreigners of European origin are included within category 6) above. See Boletin Oficial de la Republica Argentina, No. 26.495, 27 October 1988, p. 95. Under Resolution 179/88-MI (Minister of the Interior) of 19 February 1988, Resolution No. 2479/87-DNM, which suspended temporarily the authorization of entry permits, settling, and visitation for foreigners of Taiwanese origin, is without effect and the National Directorate of Migration is instructed to establish a system of strict control of such persons. See Boletin Oficial de la Republica Argentina, No. 26.495, 27 October 1988, pp. 26-27. Resolution No. 2364 (National Director of Migration) of 2 September 1988 sets forth rules on the migration status of persons who entered Argentina before Decree No. 1434/87 came into effect. Those who entered the country in compliance with regulations applicable at the time are to be given permanent or temporary residency. Most of those who entered illegally will have to leave. See Boletin Official de la Republica Argentina, No. 26.304, 13 January 1988, p. 3.

Americas↗