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PubMed1991

Cytochemical evidence of an organized microtubular cytoskeleton in Xenopus laevis oocytes: involvement in the segregation of mitochondrial populations.

An organized microtubular cytoskeleton was discovered in the cytoplasm of Xenopus laevis oocytes. The microtubules were observed in 10- to 30-micron cryostat sections by indirect immunoperoxidase labeling using an antibody to tubulin. A gradual extraction of cells with a nonionic detergent was essential for good penetration of the antibody into the cells. In the cytoplasm of all previtellogenic oocytes, a dense network of criss-crossed long microtubules was associated in a basket-like structure surrounding the mitochondrial mass. At the beginning of vitellogenesis, the network meshes enlarged, while clusters of mitochondria migrated, in close association with microtubule bundles. At the beginning of vitellogenesis, the reorganization of the microtubular network, mostly in the vegetal hemisphere, occurred during the segregation of the mitochondrial populations. Reorganization is characterized by (1) a temporary enlargement of the network and close association of mitochondrial clusters with microtubular bundles, and (2) a progressive organization of a ring-shaped microtubular structure in the crown elaboration area. It is hypothesized that these modifications of the microtubular cytoskeleton contribute to the maintenance of cell shape and the polarized organization of the cell.

Animals↗
PubMed1976

Action of midcycle contraceptive (R 2323) on the human endometrium.

Over 2,148 cycles of midcycle oral administration of R 2323 (50 mg. per day on Days 15,16, and 17), the authors recorded a drug-failure pregnancy rate of 5 per cent and an unusually regular cycle length of 28 +/- 2 days. During this trial, endometrial biopsies obtained in the luteal phase were examined by light and electron microscopy and compared to pretreatment biopsies. Light microscopy indicated a weakly secretory endometrium suggestive of some, albeit low, progesterone impregnation. Ultrastructural examination revealed deleterious changes in the development of the nucleolar channel system and giant mitochondria and a delay in the migration of glycogen granules. This low progesterone impregnation could be explained either by a direct effect of R 2323 on cell ultrastructure or by interference with progesterone availability. It would appear that R 2323 acts as a temporary substitute for progesterone at the receptor level but that it does not induce all the biological manifestations of this hormone, in particular, the endometrial changes required for implantation.

Biopsy↗
PubMedDate not supplied

[Mollusks associated to the submerged roots of the red mangrove, Rhizophora mangle (L.), in the Gulf of Santa Fe, Sucre State, Venezuela].

A qualitative and quantitative monthly study of the mollusks community associated to the submerged roots of the red mangrove, Rhizophora mangle (L.), between October of 1998 and September of 1999, in six stations of the Gulf of Santa Fe, (Sucre State, Venezuela). Were collected 4,704 specimens, 45 species of mollusks were identified (22 gastropods, 15 bivalves and 8 chitons). The most abundant species were: Crassostrea rhizophorae, Isognomon bicolar, I. alatus and Brachidontes exustus. The highest values in diversity and evenness, and the smallest dominant values, were in the stations three and four, while the opposed happened in the stations one and two. The analysis of likeness showed that in the first five stations the space variations in the composition of the community are bigger than the temporary variations, while in the station six the temporary differences prevail. They were factors that could be important to determine the structure of the community, as vicinity to other ecosystems and/or specific biological aspects of the species like adaptations to fluctuating conditions, nutritious habits and migration in search of shady and protected atmospheres.

Animals↗
PubMed1985

A new method for correlating pancreatic and biliary duct pressures and sphincter of Oddi electromyography.

Myoelectric activity of the sphincter of Oddi and duodenum was correlated with pancreatic and biliary duct pressures in eight opossums, in both the fasted and fed states. Four bipolar electrode pairs were implanted in the sphincter of Oddi and duodenum. A polyethylene T tube was placed in the pancreatic duct. The common duct was cannulated through a small bile duct. This method allowed pressure recording for several weeks and avoided interference with the flow of bile or pancreatic juice into the duodenum. The frequency of slow waves was the same in the sphincter of Oddi and duodenum (19 per minute). The variation in the frequency of spike potentials in the sphincter of Oddi correlated to that of the migrating myoelectric complex in the duodenum. The average frequency of slow waves that have superimposed spike potentials in the sphincter of Oddi and duodenum was 3.0 and 0 in phase 1, 4.7, and 6.2 in phase II, 6.1 and 15.1 in phase III, and 3.4 and 6.3 in phase IV, respectively. The average duration of a migrating myoelectric complex cycle was 92 minutes. After feeding, the interdigestive phases of the migrating myoelectric complex were abolished and substituted by a feeding activity pattern that was characterized by an average number of sphincter of Oddi and duodenum spikes of 6.6 and 10.7, respectively. The mean fasting pressure in the pancreatic and biliary duct was 15 and 13 mmHg, respectively. Pressure changes were of two types--synchronous with respiratory movements and with each sphincter of Oddi spike potential. There was no variation in the baseline pressure during the migrating myoelectric complex phases and the fed state. It is concluded that the sphincter of Oddi of the fasting opossum exhibits cyclic changes in the number of spike potentials that correlate with the migrating myoelectric complex in the duodenum. However, the number and amplitude of spike potentials are different in the sphincter of Oddi and duodenum. There is no change in the baseline pressure during fasting and feeding states, and a temporary pressure elevation synchronic with each sphincter of Oddi spike potential was observed.

Action Potentials↗
PubMed1997

A multidisciplinary approach to restoring posterior bite collapse.

Treatment planning of posterior bite collapse cases with loss of vertical dimension can be complex. In cases where a patient's vertical dimension of occlusion has been lost, there often is drifting of posterior teeth, flaring of maxillary anterior teeth, and inadequate interarch space for a restoration. These factors are further complicated by the esthetic demands of the patient and the dentist and by the use of implants to replace missing teeth. This article presents a case report of a multidisciplinary treatment plan to achieve a functional and esthetic restoration.

Alveolar Ridge Augmentation↗
PubMed1996

Successful atrial defibrillation with very-low-energy shocks by means of temporary epicardial wire electrodes.

Sustained atrial fibrillation is very common after cardiac surgical procedures. We hypothesized that atrial defibrillation could be accomplished consistently and safely by means of low-energy shocks delivered by temporary stainless steel wire electrodes placed at the time of the operation. Sterile pericarditis was created in five mongrel dogs (20.9 +/- 2.1 kg), and pairs of standard temporary stainless steel wire electrodes were placed on the right atrial appendage, on Bachmann's bundle, and on the right ventricular apex for pacing, sensing, and recording. Temporary stainless steel wire electrodes, insulated except for the distal 6 cm and used to deliver defibrillation shocks, were placed adjacent to both atrial free walls and secured to the pericardium. All electrodes were brought out through the skin, and the sternotomy was closed. Dogs were tested in the conscious state on postoperative day 2. Sustained atrial fibrillation was induced by rapid atrial pacing. A customized software program was used to control the defibrillator, which delivered R wave-synchronous biphasic shocks to the atria through the temporary defibrillation electrodes. The shock intensity began at 50 volts and was increased by 10-volt increments until atrial fibrillation was terminated. Atrial fibrillation was terminated in all dogs at 112 +/- 7 volts, with an energy of 0.42 +/- 0.07 joule and an impedance of 67.8 +/- 4 ohms (all values mean +/- standard error of the mean). The mean percent success for atrial defibrillation at this minimal threshold was 49%. Thus at low-threshold voltages atrial fibrillation could be terminated with every other shock. A 25% increase in the minimal threshold voltage improved the conversion rate to 73% (mean energy 0.66 +/- 0.19 joule and mean impedance of 67 +/- 3.8 ohms). No complications were detected with the use of the electrodes or after their removal on the seventh postoperative day. One instance of electrode migration on the right atrial free wall was detected by roentgenography, but this did not adversely affect atrial defibrillation threshold. No ventricular arrhythmias or hemodynamic complications were noted during shock delivery. We conclude that successful conversion of atrial fibrillation to sinus rhythm can be achieved consistently with shock energies below 0.5 joule delivered with temporary epicardial defibrillation wire electrodes in this canine pericarditis model. These results suggest that this approach to the management of sustained atrial tachyarrhythmias has considerable promise in the management of atrial fibrillation in patients who have had cardiac operations.

Animals↗
PubMed2004

Temporary placement of an expandable polyester silicone-covered stent for treatment of refractory benign esophageal strictures.

BACKGROUND: Benign, refractory esophageal strictures are an important therapeutic challenge. Metal stents occasionally have been used, but results have been disappointing. The present study assessed the safety and the efficacy of temporary placement of the new expandable polyester silicone-covered stent for management of problematic esophageal strictures. METHODS: Fifteen patients with benign esophageal strictures were treated by temporary (6 weeks) placement of an expandable polyester silicone-covered stent. All patients had previously been treated, unsuccessfully, by repetitive endoscopic dilation. RESULTS: Stent placement was successful in all patients. There was no procedure-related complication. Dilation with over-the-guidewire polyvinyl dilators was required before stent placement. With the stent in situ, dysphagia completely resolved in all patients. Six weeks after placement, one stent was found to have migrated into the stomach. In the remaining patients, the stent was easily removed with a foreign body forceps. The pretreatment dysphagia score was 3 (range 2-4); the post-treatment score was 1 (range 0-1) (p < 0.0005). Long-term resolution (mean follow-up 22.7 [2.6] months) of the stricture was achieved in 12 patients (80%). The treatment failed in 3 patients, all of whom continue to require periodic dilation. CONCLUSIONS: In patients with benign esophageal strictures refractory to conventional dilation, temporary placement of a removable expandable polyester silicone-covered stent may lead to long-term relief of dysphagia with minimal morbidity.

Adult↗
PubMed2006

Use of Polyflex stents in treatment of acute esophageal and gastric leaks after bariatric surgery.

BACKGROUND: This study examined the feasibility of using Polyflex stents in the treatment of enteric leaks after various bariatric operations. Chronic and acute leaks were treated. METHODS: We performed a retrospective case series review. Four patients received 6 Polyflex stents to treat complications of bariatric surgery. Two presented with early sepsis before stenting. One presented with abdominal pain. One presented with a chronic persistent fistula with an associated abscess. Stenting was performed under endoscopy with fluoroscopic guidance. The stents were left in place for 6 weeks. RESULTS: All patients tolerated a clear liquid diet within 24 hours of stenting and were able to be advanced to a pureed diet. All patients improved clinically after stenting. Three patients with acute leaks sealed their leaks after stent placement. One patient with a chronic leak persisted and required operative closure after a second stent was placed and failed. All patients experienced short-term nausea, as well as early satiety that lasted the duration of the stenting. One patient experienced hypersialisis while the stent was in place. Two stents migrated, although this had no effect on leak closure. One patient had an anastomotic stenosis successfully treated with a second stent. CONCLUSIONS: Polyflex stents are useful in bypassing acute upper intestinal leaks after various bariatric operations. They provide a temporary bridge for wound healing with continued oral intake. Stenting provides a minimally invasive option in the management of acute leaks and, in our experience, had no serious associated morbidity.

Adult↗
PubMed2005

Temporary stenting of acquired benign tracheoesophageal fistulas in critically ill ventilated patients.

BACKGROUND: To evaluate the use of esophageal stents for temporary sealing of acquired benign tracheoesophageal fistulas developed in critically ill, ventilated patients. METHODS: This is a retrospective analysis (1992-2003) of the data of 12 mechanically ventilated patients - six of them after major or multiple trauma - being intubated for a median of 30 days before they develop an acquired benign tracheoesophageal fistula. Five of them were in sepsis. Two types of stents were used: the Wilson-Cook esophageal balloon plastic stent in the first four cases and the Ultraflex covered self-expandable stent in the remaining eight. The total procedure was performed at bedside in the intensive care unit, with no special need for supplementary anesthesia or fluoroscopic control. RESULTS: Stent implantation was technically successful in all patients and fistula occlusion was achieved in every case. There was no stent migration and fistulas remained sealed until death or upon decision for removal. Nine patients died between 5 days and 2 months after stent placement, as a result of their diseases. Three patients were referred for fistula surgical repair 33, 36, and 43 days after stent placement. Before surgery the stents were easily removed under direct vision. CONCLUSION: Temporary closure of an acquired tracheoesophageal fistula developed in critically ill ventilated patients is an easy, bedside-applicable, safe, and effective palliative procedure, with no complications or mortality.

Adult↗
PubMed2006

Cell proliferation in the adult rat rostral migratory stream following exposure to gamma irradiation.

One of the few areas of the adult CNS, that are known to be competent for neuronal proliferation, is the subventricular zone (SVZ) lining the brain lateral ventricles. Cells proliferating in the SVZ migrate along a defined pathway, the rostral migratory stream (RMS), where their proliferation continues until reaching the olfactory bulb. 1. In relation to the fact that brain is, in general, regarded as a radioresistant organ composed from non dividing cells, the aim of the present study was to investigate effect of ionizing radiation on proliferating cell numbers in the RMS of adult rats. 2. Male Wistar rats were investigated 25 and 80 days after whole body gamma irradiation with the dose of 3 Gy. Dividing cells were labeled by bromodeoxyuridine (BrdU). BrdU-positive cells were counted by Disector program. The mean number of BrdU(+) cells in the whole RMS and in its individual parts (vertical arm, elbow, and horizontal arm) was evaluated. 3. Temporary increase in proliferating cell number (by 30%) was seen in the whole RMS at the 25th day after irradiation. 4. The most expressive increase occurred in the vertical arm (by 60%) and elbow (about 37%). The values reduced till the 80th day after exposure. Our results show that ionizing irradiation significantly influences the extent of cell proliferation and migration in the adult rat RMS.

Animals↗
PubMed1981

Effects of colchicine on gap junction formation during retinal neurogenesis.

Colchicine, injected into the amniotic cavity of 3 to 10 day-old chick embryos, has the following effects on the developing retina: 1. Cells in arrested metaphase accumulate in the ventricular portion of the matrix region. If colchicine is applied at the end of the first week of incubation, the kinetic migration of the cell nuclei is inhibited. 2. The cells lose their typical slender, bipolar shape to become ovoid to spherical. These morphological changes are more obvious when colchicine acts during the first week of incubation. 3. The formation of temporary gap junctions between the matrix cells of the retina occurs during the first week of development. When colchicine is administered around the 3rd day of incubation, the assembly of intramembranous particles (IMPs) during gap junctions formation is incomplete. These results suggest that an intact microtubular system within the submembranous cytoskeleton is essential for the assembly of these intercellular contacts.

Animals↗
PubMed1980

[Linkage disequilibrium].

The linkage disequilibrium which measures the association between linked genes is a temporary phenomenon in a population because of crossing over. But such associations persist in HLA system. These persistent linkage disequilibria may be due to the very small fraction of recombinaison between the loci but other explanations are possible: selection or migration. A linkage disequilibrium produces a phenotypic correlation in a population. A phenotypic correlation may be due to pleiotropic effect of a gene, or epistasie of two genes, or population stratification... On the same hand, if a correlation appears in an inter population study, it may be due to a migration or a subdivided population. In medical genetics the research of such association intra or inter population studies may permit to point out a defect gene. In particular, HLA system study has proved that many susceptibility genes of various diseases are linked to B or D alleles.

Female↗
PubMedDate not supplied

[Loco-regional thrombolysis in deep venous thrombosis].

Anticoagulation, by means of heparin and warfarin is, till now, the most common treatment in deep venous thrombosis. Although thrombolytic agents have been available for over 10 years, their use remains quite low, ranging from 15 to 20% of deep venous thromboses. This is due to the relatively high incidence of contraindications as well as to the fact that the potential advantages versus heparin are diminished by the increased bleeding risk and by the potential risk of pulmonary embolism (migration of partially lysed thrombi). Following the example of the "triple armed therapy" proposed by Rosenthal for the treatment of pulmonary embolism, we will evaluate if loco-regional thrombolysis, with the catheter wedged against the thrombus, associated with a temporary vena cava interruption by means of an intraluminal filter, can achieve a better lysis of the thrombus without pulmonary embolism. In our Unit 18 patients affected by proximal deep venous thrombosis were submitted to thrombolytic therapy, 6 to systemic treatment, 3 to local treatment and the last 9 to loco-regional thrombolysis, using recombinant tissue-type Plasminogen Activator. We obtained 10 complete lyses, 1 with systemic and 9 with loco-regional treatment. There were no major complications. Thus, we think that venous loco-regional thrombolysis with rt-PA at lower doses, associated with temporary caval interruption, can probably achieve a better lysis than systemic treatment without risk of pulmonary embolism and with a very low haemorrhagic risk, as in arterial loco-regional thrombolysis. Furthermore, loco-regional thrombolysis, by means of a faster thrombus dissolution, could better prevent post-phlebitic syndrome.

Catheterization, Peripheral↗
PubMed2002

Mid-term results of an endovascular stent-graft by means of median sternotomy for distal aortic arch aneurysm.

Migration and perigraft leakage are major problems after endovascular stent graft (EVG) by means of median sternotomy for distal aortic arch aneurysm. Anchoring sutures have been applied to prevent these problems. We evaluate the mid-term results and the efficacy of anchoring sutures. The operation was performed on 19 men and 2 women with a mean age of 70 years (range, 59-81). The aneurysms were 19 true (12 fusiform, 7 saccular), 1 chronic dissection, and 1 penetrating aortic ulcer. EGVs were implanted by way of the aortic arch under retrograde cerebral perfusion in 13 patients and selective cerebral perfusion in 8. Total arch replacement was performed in 2 patients, and aortocoronary bypass grafting in 4. Anchoring sutures to fix the EVG were applied in 9 patients. The average follow-up period was 28 months (range, 2-56). There were no operative mortalities, but 1 paraplegia, 1 stroke, and 2 cases of temporary spinal cord dysfunction occurred. All aneurysms were thrombosed completely after surgery and reduced in diameter (66.9 +/- 17.4 mm to 57.3 +/- 15.7 mm, p < 0.0001). EVG-related complications arose in 4 patients. A chronic Type B dissection revealed impending rupture because of false lumen infection 1 year after operation, and redo surgery was performed. Migration occurred in 3 patients, all with fusiform aneurysms. One of these had a graft kink 1 year later. Another showed aneurysm enlargement with serous pleural effusion 3 years after operation. The third required redo surgery because of perigraft leakage at 3 years after surgery. There were 2 late deaths caused by stroke. There were no EVG-related complications in the 9 cases in which anchoring sutures were applied and in the 7 cases with saccular aneurysms. No spinal cord dysfunction occurred in 8 cases with low-flow antegrade perfusion by way of both axillary arteries while the aorta was opened. Logistic regression analysis showed significant relevance to complications of large aneurysms, greater than 80 mm in diameter. A large aneurysm tends to give rise to complications involving EVG migration. Anchoring sutures of EVG may prevent EVG-related complications.

Aged↗
PubMed2001

A novel approach to ex vivo gene therapy for familial hypercholesterolemia using human amniotic epithelial cells as a transgene carrier.

This study has demonstrated the potential of human amniotic epithelial cells (HAEC) as a transgene carrier to treat patients with familial hypercholesterolemia (FH). One approach to liver-directed gene therapy is represented by transplantation of autologous hepatocytes that have been genetically modified in vitro. However, the hepatocytes must be isolated from surgically resected tissue and it is difficult to expand the hepatocytes in culture. In contrast, the advantages for using HAEC are the higher availability and the nonimmunogenicity after allotransplantation. Our strategy involved isolating HAEC from an amnion, transducing a human low-density lipoprotein receptor (LDLR) gene into these cells with a recombinant adenovirus, and transplanting the genetically modified cells into the liver of an animal model of FH. Each animal, treated with the LDLR-transduced HAEC, exhibited a substantial decrease in serum cholesterol with an eventual return to pretreatment level. Moreover, the transplanted HAEC migrated out of the sinusoids into the hepatic parenchyma and expressed the LDLRs until at least 20 days after transplantation. However, the transplanted HAEC markedly decreased in number after 10 days post-transplant with an increase of inflammatory cells. The temporary nature of the metabolic improvement may be associated with xenograft rejection and transient function of the adenoviral vector.

Adenoviruses, Human↗
PubMed1993

Implantation and recovery of temporary metallic stents in canine coronary arteries.

OBJECTIVES: The purpose of this study was to test the feasibility of implanting and retrieving a heat-activated recoverable temporary stent and to determine its effect on the angiographic, gross and histologic appearance of a normal coronary artery wall. BACKGROUND: Permanent coronary stenting is associated with a significant incidence of thrombosis, bleeding and vascular complications. These may be avoided by temporarily stenting for a period of hours to several days. METHODS: Seventy-eight stents constructed from the shape-memory nickel-titanium alloy nitinol were deployed by balloon expansion in the coronary arteries of 28 dogs and left in place for up to 6 months. Thirty minutes to 1 week after implantation, 70 stents were recovered by flushing the coronary arteries with 3 to 5 ml of 75 degrees C lactated Ringer solution, with collapse of the stent over a recovery catheter and subsequent withdrawal. RESULTS: All stents were successfully recovered and removed percutaneously. Mean vessel diameter after stenting was 12 +/- 6% (p < 0.05) greater than baseline diameter. Mean vessel diameter after stent removal remained enlarged (6 +/- 3%, p < 0.05). No angiographic or gross evidence of thrombosis, dissection, embolization, migration or spasm was associated with implantation or recovery. Microscopic examination revealed minor intimal injury in 40 segments (51%). Microscopic focal medial necrosis was associated with mural platelet-fibrin thrombus in 23 stented segments (29%) and media was interrupted in 7 (9%). CONCLUSIONS: This study demonstrates the feasibility of a new method of temporary stenting that uses the thermoelastic properties of nitinol to permit reliable recovery of the stent in normal canine coronary arteries.

Alloys↗
PubMed2005

Real-time detection of migratory thrombi by transesophageal echocardiography in a patient undergoing thrombectomy.

We report a 44-year-old male patient who sustained a right atrial (RA) thrombosis with evolvement into right pulmonary artery embolism in consequence of placement of a temporary pacing lead and was successfully treated with surgical thrombectomy under the guidance of perioperative transesophageal echocardiography (TEE). Because of intermittent complete atrioventricular block he therefore underwent implantation of a transvenous temporary pacing. On the ensuing day a large mass was incidentally found echographically in the RA suggestive of a large thrombus. Immediate surgical removal of the mass was indicated. During the emergent open-heart surgery the mass in RA dehiscenced with fragments migrating to the right main pulmonary artery, and exploration of both the RA and right pulmonary artery was done. This migratory mass, which proved to be a fresh thrombus, was surgically removed. The cardiopulmonary bypass was then terminated and the spontaneous contraction of heart was resumed. However, another mass lesion was found in RA on the TEE screen just following the removal of the problematic transvenous pacing wire. The right atrium was thus re-opened immediately and the second thrombus was cleared. Over the on-going surgical course no further abnormal echogenic objects were visible in the cardiac chambers. It is perceivable that transvenous pacing might cause thrombois or dislodgement and dehiscence of thrombi already in existence in the cardiac chamber. Careful and continuous intraoperative surveillance with echocardiography over a patient who is undergoing cardiac embolectomy is quite important in detecting thrombus escape and residual thrombi during surgery.

Adult↗
PubMed2000

Policies of deterrence and the mental health of asylum seekers.

In the past, most refugees who permanently resettled in the traditional recipient countries of North America, Europe, and Australasia were screened prior to arrival in a host country. In the last decade, increasing numbers of unauthorized refugees or asylum seekers, those who formally lodge application for refugee status in the country in which they are residing, have applied for protection after crossing the borders of these countries. Concerns about uncontrolled migration have encouraged host countries to adopt policies of deterrence in which increasingly restrictive measures are being imposed on persons seeking asylum. These measures include, variously, confinement in detention centers, enforced dispersal within the community, the implementation of more stringent refugee determination procedures, and temporary forms of asylum. In several countries, asylum seekers living in the community face restricted access to work, education, housing, welfare, and, in some situations, to basic health care services. Allegations of abuse, untreated medical and psychiatric illnesses, suicidal behavior, hunger strikes, and outbreaks of violence among asylum seekers in detention centers have been reported. Although systematic research into the mental health of asylum seekers is in its infancy, and methods are limited by sampling difficulties, there is growing evidence that salient postmigration stress facing asylum seekers adds to the effect of previous trauma in creating risk of ongoing posttraumatic stress disorder and other psychiatric symptoms. The medical profession has a role in educating governments and the public about the potential risks of imposing excessively harsh policies of deterrence on the mental health of asylum seekers. JAMA. 2000;284:604-611

Depressive Disorder↗