Reactivity and structural evolution of urchin-like Co nanostructures under controlled environments.

In situ transmission electron microscopy (TEM) of samples in a controlled gas environment allows for the real time study of the dynamical changes in nanomaterials at high temperatures and pressures up to the ambient pressure (105 Pa) with a spatial resolution close to the atomic scale. In the field of catalysis, the implementation and quantitative use of in situ procedures are fundamental for a better understanding of the behaviour of catalysts in their environments and operating conditions. By using a microelectromechanical systems (MEMS)-based atmospheric gas cell, we have studied the thermal stability and the reactivity of crystalline cobalt nanostructures with initial 'urchin-like' morphologies sustained by native surface ligands that result from their synthesis reaction. We have evidenced various behaviors of the Co nanostructures that depend on the environment used during the observations. At high temperature under vacuum or in an inert atmosphere, the migration of Co atoms towards the core of the particles is activated and leads to the formation of carbon nanostructures using as a template the initial multipods morphology. In the case of reactive environments, for example, pure oxygen, our investigation allowed to directly monitor the voids formation through the Kirkendall effect. Once the nanostructures were oxidised, it was possible to reduce them back to the metallic phase using a dihydrogen flux. Under a pure hydrogen atmosphere, the sintering of the whole structure occurred, which illustrates the high reactivity of such structures as well as the fundamental role of the present ligands as morphology stabilisers. The last type of environmental study under pure CO and syngas (i.e. a mixture of H2 :CO = 2:1) revealed the metal particles carburisation at high temperature.

A posterior approach pancreaticoduodenectomy with portal vein resection in a large adenocarcinoma of the uncinate process of the pancreas - case report.

A portal vein invasion is no longer a contraindication for resection in pancreatic cancer, but increased morbidity and mortality rates can be encountered. Hereby it is presented the case of a patient diagnosed with a large adenocarcinoma of the uncinate process of the pancreas, who underwent aposterior approach pancreaticoduodenectomy, with en bloctang ential resection of the portal vein, and total mesopan creasexcision. A posterior approach allows a negative resection margins pancreaticoduodenectomy, with a good local control of the disease, despite the in creas.

Anatomo-clinical analysis of 14 consecutive cases of primary cystic mesenterico-epiploic tumors.

BACKGROUND: The aim of this study is an anatomo-clinical evaluation of the primary cystic mesenterico-epiploic tumors,based on a single-center's 15 year experience. MATERIAL AND METHOD: We performed a retrospective study of a series of 14 primary cystic mesenterico-epiploic tumors that were operated in the Surgical Department 4 UMPh Targu-Mures, Romania, between 01.01.1997 and 01.01.2012. Data about the clinical complaints, imagistic aspects, associated lesions, surgical approach, hospitalization, pathology, and immediate and late postoperative course were recorded and analysed using the Microsoft Excel software. RESULTS: In all cases we performed a complete and intact surgical excision, using an open approach in 13 cases and laparoscopy in 1 case, with no mortality and no significant surgical-related morbidity; we have encountered a single recurrence at 1.5 years after surgery. We had no preoperative pathological diagnosis; the exact preoperative anatomic location of the tumor was possible only in one case. Pathologic examination showed the following types: inclusion cysts - 4 cases, enteral duplication cysts - 2 cases, simple mesothelialcysts - 6 cases, cystic lymphangioma - 1 case and simple lymphatic cyst - 1 case. We have systematized 3 clinicoimagistic patterns according to the dimension of the tumor,with no relationship to the histologic origin of the tumor. CONCLUSIONS: Primary cystic mesenterico-epiploic tumors aredifficult to diagnose preoperatively. Complete excision is usually possible, even for large tumors. These relatively rare tumors must be considered in the differential diagnosis of cystic abdominal masses.

Bright and ultrafast electron point source made of LaB6 nanotip.

The development of time-resolved transmission electron microscopy (TEM), ultrafast electron spectroscopy and pulsed X-ray sources relies on the realization of stable and high brightness sources of ultra-short electron bunches with a long service time. The flat photocathodes implanted in thermionic electron guns have been replaced by Schottky-type or cold-field emission sources driven by ultra-fast laser. Recently, lanthanum hexaboride (LaB6) nanoneedles have been reported to have high brightness and high emission stability when working in a continuous emission mode. Here, we prepare nano-field emitters from bulk LaB6 and we report on their use as ultra-fast electron sources. Using a high repetition rate laser in the infrared range, we present different field emission regimes as a function of the extraction voltage and laser intensity. The properties of the electron source (brightness, stability, energy spectrum and emission pattern) are determined for the different regimes. Our results show that LaB6 nanoneedles can be used as ultrafast and ultra-bright sources for time-resolved TEM, with better performances as compared to metallic ultra-fast field-emitters.

The advantages of retropancreatic vascular dissection for pancreatic head cancer with portal/superior mesenteric vein invasion: posterior approach pancreatico-duodenectomy technique and the mesopancreas theory.

UNLABELLED: BACKROUNDS/AIMS: Surgery remains the single hope for long-term survival long-term survival in pancreatic head carcinoma. Portal vein invasion is no longer a contraindication for resection but could be technically challenging. The aim of the present study is to emphasize the advantages of the posterior approach in duodenopancreatectomy with portal vein resection. METHODS: The present series includes 16 patients with duodenopancreatectomy and portal/superior mesenteric vein resection and reconstruction duodenopancreatectomy invading the venous axis, performed from 2004 to 2011, and representing one author's experience. RESULTS: A lateral resection with direct suture was performed in 10 patients and the length of the resected venous wall was less than 1.2 cm. A segmental resection was performed in six patients and the length of resected vein did not exceed 3 cm (range, 1.5 - 3 cm). All venous resection extremities were cancer-free at final pathological report. Eleven patients were considered as R0 resection while 5 patients were assessed as R1 at final pathological examination. Postoperative morbidity consisted of: 3 patients with postoperative pancreatic fistulae (grade A - 2 patients; grade C - 1 patient, requiring second look laparotomy for peri-pancreatic abscesses) and 5 patients with delayed gastric emptying grade B. CONCLUSION: Portal/superior mesenteric vein resection during duodenopancreatectomy is safe and it is facilitated by the posterior approach. Moreover, the posterior approach facilitates total mesopancreas excision during duodenopancreatectomy for pancreatic head cancer, a technical feature that appears to be associated with an increased rate of negative resection margins.

A photonic atom probe coupling 3D atomic scale analysis with in situ photoluminescence spectroscopy.

Laser enhanced field evaporation of surface atoms in laser-assisted Atom Probe Tomography (APT) can simultaneously excite photoluminescence in semiconductor or insulating specimens. An atom probe equipped with appropriate focalization and collection optics has been coupled with an in situ micro-photoluminescence (µPL) bench that can be operated during APT analysis. The photonic atom probe instrument we have developed operates at frequencies up to 500 kHz and is controlled by 150 fs laser pulses tunable in energy in a large spectral range (spanning from deep UV to near IR). Micro-PL spectroscopy is performed using a 320 mm focal length spectrometer equipped with a CCD camera for time-integrated and with a streak camera for time-resolved acquisitions. An example of application of this instrument on a multi-quantum well oxide heterostructure sample illustrates the potential of this new generation of tomographic atom probes.

In situ insight into the unconventional ruthenium catalyzed growth of carbon nanostructures.

We report on the in situ analysis of the growth process of carbon nanostructures catalyzed by Ru nanoparticles using syngas, a mixture of hydrogen and CO, as the carbon source at a medium temperature (500 °C). The structural modifications of the dual nanotube/nanoparticle system and the general dynamics of the involved processes have been directly followed during the growth, in real time and at the atomic scale, by transmission electron microscopy in an environmental gas cell at atmospheric pressure. After a reduction step under hydrogen and syngas, the particles became very active for the carbon growth. The growth rate is independent of the particle size which mainly influences the nanotube wall thickness. Other subtle information on the general behavior of the system has been obtained, as for instance the fact that the regular changes in the direction of the particle originate generally from the particle shape fluctuation. The main result is the evidence of a new growth mode in relation to the presence and the high instability of the ruthenium carbide phase which acts as a carbon reservoir. For the first time, a relaxation oscillation of the growth rate has been observed and correlated with the metal-carbide structural transition at the particle sub-surface.

Synthesis engineering of iron oxide raspberry-shaped nanostructures.

Magnetic porous nanostructures consisting of oriented aggregates of iron oxide nanocrystals display very interesting properties such as a lower oxidation state of magnetite, and enhanced saturation magnetization in comparison with individual nanoparticles of similar sizes and porosity. However, the formation mechanism of these promising nanostructures is not well understood, which hampers the fine tuning of their magnetic properties, for instance by doping them with other elements. Therefore the formation mechanism of porous raspberry shaped nanostructures (RSNs) synthesized by a one-pot polyol solvothermal method has been investigated in detail from the early stages by using a wide panel of characterization techniques, and especially by performing original in situ HR-TEM studies in temperature. A time-resolved study showed the intermediate formation of an amorphous iron alkoxide phase with a plate-like lamellar structure (PLS). Then, the fine investigation of PLS transformation upon heating up to 500 °C confirmed that the synthesis of RSNs involves two iron precursors: the starting one (hydrated iron chlorides) and the in situ formed iron alkoxide precursor which decomposes with time and heating and contributes to the growth step of nanostructures. Such an understanding of the formation mechanism of RSNs is necessary to envision efficient and rational enhancement of their magnetic properties.

Towards nanoprinting with metals on graphene.

Graphene and carbon nanotubes are envisaged as suitable materials for the fabrication of the new generation of nanoelectronics. The controlled patterning of such nanostructures with metal nanoparticles is conditioned by the transfer between a recipient and the surface to pattern. Electromigration under the impact of an applied voltage stands at the base of printing discrete digits at the nanoscale. Here we report the use of carbon nanotubes as nanoreservoirs for iron nanoparticles transfer on few-layer graphene. An initial Joule-induced annealing is required to ensure the control of the mass transfer with the nanotube acting as a 'pen' for the writing process. By applying a voltage, the tube filled with metal nanoparticles can deposit metal on the surface of the graphene sheet at precise locations. The reverse transfer of nanoparticles from the graphene surface to the nanotube when changing the voltage polarity opens the way for error corrections.

Deficiency of somatostatin (SST) receptor type 5 (SSTR5) is associated with sexually dimorphic changes in the expression of SST and SST receptors in brain and pancreas.

The actions of somatostatin (SST) are mediated through five somatostatin receptor subtypes, termed SSTR1-5. Although SSTRs commonly display an overlapping pattern of tissue distribution, subtype-selective responses have been shown to occur in the same tissue. In the present study, we have investigated the changes in SSTR subtypes at the cellular and molecular level in both the brain and the pancreatic islets of mice deficient in SSTR5 (SSTR5KO). Expression levels of insulin and glucagon were also determined in the pancreas of these mice. Semi-quantitative RT-PCR and Western blot analysis showed significant increases in the expression of SSTR2 and 3 with a corresponding reduction in SSTR4 in the brains of female SSTR5KOs, while no changes were observed in male KOs. Strikingly, SST mRNA and SST-like immunoreactivity (SST-LI) were reduced in the brain of male KO animals but not in their female counterparts. In male SSTR5KO islets, there was an increase in the number of cells immunoreactive for SSTR1-3, whereas in female islets only SSTR3 expression was increased. Pancreatic SST-LI and SST mRNA, as well as immunoreactivity for insulin were reduced in male but not in female KO mice. These data indicate that deficiency of SSTR5 leads to subtype-selective sexually dimorphic changes in the expression of both brain and pancreatic SSTRs.

Double-gene ablation of SSTR1 and SSTR5 results in hyperinsulinemia and improved glucose tolerance in mice.

BACKGROUND: Previous studies conducted in our laboratory showed that single-gene ablation of somatostatin receptor (SSTR)1 or 5 results in diabetes in mice. The objective of this study was to determine the effect of double-gene ablation of SSTR1 and SSTR5 on insulin secretion and glucose homeostasis in mice. METHODS: SSTR1/5 -/- mice and wild-type (WT) control mice were generated and their genotype verified via polymerase chain reaction. Insulin secretion and glucose levels in these mice were examined with the use of an intraperitoneal glucose tolerance test (1.2-2.0 g/kg body weight). In vitro glucose-stimulated insulin secretion was studied with the use of the isolated perfused mouse pancreas model and islet culture techniques. Pancreata morphologic alterations were determined, and an immunohistochemistry analysis was performed. RESULTS: In vitro incubation of isolated islets from WT mice with somatostatin peptides resulted in significant reduction in insulin secretion, whereas SSTR1/5 -/- mouse islets had no response to somatostatin peptides confirming SSTR1/5 gene ablation. SSTR1/5 -/- mice also had significant increase of both basal and glucose-stimulated insulin levels in vitro. During the intraperitoneal glucose tolerance test, SSTR1/5 -/- mice had significantly improved glucose tolerance and sustained an increase in late-phase insulin secretion in vivo. Histological analysis demonstrated significant islet hyperplasia in the SSTR 1/5 -/- mouse pancreas. Immunostaining revealed an overall increase of glucagon and pancreatic polypeptide-producing cells in the islets of SSTR1/5 -/- mice. CONCLUSIONS: Double-gene ablation of SSTR1 and SSTR5 in mice resulted in a distinct phenotype with islet cell hyperplasia, hyperinsulinemia, and improved glucose tolerance. This form of diabetes differs from that seen in mice in which only the SSTR1 or SSTR5 gene was ablated. These results demonstrate that SSTR1 and SSTR5 are important regulators of insulin secretion and glucose regulation, and suggest that SSTR1 and SSTR5 are coordinately regulated.

Insulin secretion is inhibited by subtype five somatostatin receptor in the mouse.

BACKGROUND: Recently five somatostatin receptor subtypes (SSTRs) were cloned, allowing the development of highly specific agonists to these SSTRs. Previous studies have shown a species specificity phenomenon with respect to the inhibition of insulin secretion by these selective agonists. This study was undertaken to determine which SSTR (2 or 5) is responsible for the inhibitory effect of somatostatin on glucose-stimulated mouse insulin secretion. METHODS: Intact mouse islets (n = 10) were stimulated with D-glucose in the presence or absence of receptor-specific somatostatin agonists. RESULTS: D-glucose (16.7 mmol/L) augmented insulin secretion by 158% above that seen with 3.9 mmol/L D-glucose. In the presence of DC 32-92 (SSTR5) selective agonist, D-glucose (16.7 mmol/L) augmented insulin secretion by 64% above that seen with 3.9 mmol/L D-glucose. The presence of SSTR 5 selective agonist resulted in a significant (P < .05) inhibition of glucose-stimulated insulin secretion. The identification of SSTR5 within the mouse pancreas was established by reverse transcriptase polymerase chain reaction and confirmed by Southern blot analysis. CONCLUSIONS: These results suggest that the inhibitory effect of somatostatin on insulin secretion is mediated through the subtype 5 receptor within the mouse islet.

An Internet multicast symposium concerning the microcirculation of the islets of Langerhans.

The Internet Globally-linked Computer System was used to conduct an international scientific symposium. The symposium was held at the VAMC-Long Beach and consisted of prepared lectures that were multicast over the Internet. The basic unit of hardware used for the Internet Multicast was the Silicon Graphics Indy Unix Workstation, which was equipped with a color video camera. The multicast required four additional pieces of software from the file transfer protocol. The multicast backbone protocol allowed for simultaneous audio and video signals (the presenter, the slides, and the videotape images of islet microcirculation studies) to be transmitted over the computer network. The faculty included 12 experts in microcirculation, who gave 15-min lectures that included a question and answer period. All lectures were received at 14 computer stations in six countries. Eleven of the faculty gave their lectures at the VAMC-Long Beach, and one gave her lecture at the Massachusetts Institute of Technology in Boston, MA. The presenter from Boston was able to receive and answer questions from the faculty at the VAMC-Long Beach. An estimated $12,000 was saved in travel, hotel, and food costs and an estimated 180 travel hours were saved by viewers who did not have to travel to the symposium. We have demonstrated that a scientific symposium can be conducted using the Internet. We propose that many of our future meeting will be organized over the computer network. This format of multiimage projections allows us to effectively communicate in a personal way with a reduction in expensive and time-consuming travel.

Improved quality and yield of islets isolated from human pancreata using a two-step digestion method.

A new approach, involving a two-step digestion process and Los Angeles preservation solution #1 (LAP-1), a cold storage solution, was developed for isolation of high-quality islets from human pancreata for transplantation. This approach markedly improves the islet yield, purity and viability, and the isolation success rate. In this method, the pancreas was digested first in warm collagenase solution for up to 20 minutes. After decanting the enzyme solution, partially digested tissue was dissociated by gentle agitation in cold LAP-1 solution without additional collagenase. The digested tissues were stored in cold LAP-1 solution until islet purification on Euro-Ficoll. Forty-six islet isolations were performed consecutively by the new method (group 1). These results were compared to those obtained earlier with 46 consecutive isolations, using our previous method that had been used before development of the new method (group 2). Our old method was a modification of Ricordi's method involving only warm collagenase digestion and the storage of digested tissues in cold Hanks balanced salt solution. All pancreata were partial, containing the body and tail. There were no significant differences in both groups with regard to the donor age, cold ischemic time, harvesting conditions, and pancreatic weight. Pancreas digestion was completed in approximately 1 hour in both groups. The isolation success rate as determined by viable islets after 2 days in culture was 93.5% (43 of 46 cases) in group 1, and 56.5% (26 of the 46) in group 2. Immediately after isolation, the new method yielded a total of 335,739 +/- 36,244 islets equivalent to 150 microm (IEQ) and 6,233 +/- 681 IEQ/g of pancreas with 83 +/- 2.5% purity, whereas the old method yielded a total of 195,587 +/- 25,242 IEQ and 3,763 +/- 5,509 IEQ/g with 69.2 +/- 4.7% purity. Isolated islets in group 1 maintained a good three-dimensional structure, displayed normal insulin release to high glucose stimulation in vitro, and restored euglycemia after transplantation into streptozotocin-diabetic athymic mice. The two-step digestion method provides a sufficient number of islets for transplantation from a single pancreas.

LAP-1 cold preservation solution for isolation of high-quality human pancreatic islets.

The most critical factors that affect the outcome of clinical pancreatic islet transplantation are the number and quality of donor islets available for transplantation. Toward this goal, we attempted to obtain islets that are both of better quality and higher number than are obtainable by the islet-isolation process that is now widely used. We paid special attention to two critical components of the isolation procedure: minimizing the exposure of pancreatic tissue and freed islets to warm enzyme solution, and development of a preservation solution suitable for islets during cold storage of digested pancreatic tissue-free islets. For this purpose, we developed both a two-step procedure for pancreas digestion and a new cold preservation solution, the LAP-1 solution (Los Angeles preservation solution 1). In this study, we evaluated the effect of four preservation solutions by storing digested pancreatic tissues on ice for 90 min. After the cold storage, islets were purified on three layers of Euro-Ficoll solutions in a 50-ml tube, and the islet yield, viability, and function were determined. These experiments were performed by using samples from 10 consecutive islet isolations. Results with LAP-1, original University of Wisconsin solution (oUW), and modified UW solution (mUW;UW without hydroxyethyl starch) were compared with those obtained with Hank's balanced salt solution (HBSS). The islet yield was significantly higher in the LAP-1 and mUW groups as compared with the HBSS group (p < 0.01). The islet purity was significantly better in the LAP-1, oUW, and mUW groups than the HBSS (p < 0.001). The islet viability was lowest in the HBSS group immediately after purification (vs. LAP-1, oUW, and mUW, p < 0.05) and further decreased during culture (p < 0.01). Both the number and viability of cultured islets were the highest with LAP-1 solution but without statistical significance between mUW and oUW. Electron microscopic examination showed only slight damage to cell membranes immediately after purification of islets stored in LAP-1 solution and their complete recovery within 1-2 days of culture. These islets also exhibited normal insulin responses to high glucose by static incubation and perifusion assays.

Immunoneutralization of somatostatin, insulin, and glucagon causes alterations in islet cell secretion in the isolated perfused human pancreas.

INTRODUCTION: In this study, immunoneutralization of endogenous insulin, glucagon, and somatostatin with specific antibodies was used in an isolated perfused human pancreas (IPHP) model. AIMS: To study intrapancreatic cellular interactions and pancreatic hormonal secretion. METHODOLOGY: Randomized, sequential 10-minute test intervals of single-pass perfusion with each antibody were performed at 3.9 mM or 11.5 mM steady-state glucose concentrations. Somatostatin, insulin, and glucagon levels were measured in the effluent during basal and immunoneutralization intervals. RESULTS: At 3.9 mM glucose concentration, somatostatin antibody (SS-Ab) stimulated insulin and glucagon secretion, insulin antibody (IN-Ab) inhibited glucagon secretion, and glucagon antibody (GN-Ab) stimulated insulin secretion. At 11.5 mM glucose concentration, SS-Ab stimulated insulin secretion, IN-Ab stimulated glucagon and inhibited somatostatin secretion, and GN-Ab stimulated insulin secretion. CONCLUSION: The variation in hormonal responses to immunoneutralization during stimulated and nonstimulated glucose conditions suggests that a dynamic association exists between the pancreatic cells.

Intraislet somatostatin inhibits insulin (via a subtype-2 somatostatin receptor) but not islet amyloid polypeptide secretion in the isolated perfused human pancreas.

It is our hypothesis that intraislet somatostatin regulates beta cell secretion in the isolated perfused human pancreas. The present study was designed to determine the relative influence of intraislet somatostatin on the regulation of islet amyloid polypeptide (IAPP) and insulin secretion, and to determine the effect of specific somatostatin receptor (SSTR) agonists on beta cell secretion during immunoneutralization of endogenous somatostatin in the isolated perfused human pancreas. Single-pass perfusion was performed in pancreata obtained from seven cadaveric organ donors using a modified Krebs medium with 3.9 mmol/L glucose. Sequential test periods were separated by basal periods and experiments were performed by infusion of any of the following: (1) somatostatin monoclonal antibody (S-Ab); (2) S-Ab + SSTR2 agonist (DC32-87); or (3) S-Ab + SSTR5 agonist (DC32-92). The changes in insulin and IAPP secretion from basal levels during each stimulation were calculated. Infusion of S-Ab resulted in a significant increase in insulin secretion (2033 +/- 429 pmol/L; P <0.05) but not IAPP. In the presence of S-Ab, infusion of the SSTR2 agonist resulted in a significant inhibition of insulin secretion (-1128 +/- 457 pmol/L; P <0.05) but not IAPP. In the presence of S-Ab, infusion of the SSTR5 agonist had no significant effect on insulin or IAPP secretion. We conclude that intraislet somatostatin inhibits insulin secretion via SSTR2, but not IAPP secretion, in the isolated perfused human pancreas model and that this effect occurs via SSTR2. These results also suggest that insulin and IAPP secretion are regulated by different mechanisms despite being co-localized to the beta cell.

Glucose-induced islet hyperemia is mediated by nitric oxide.

PURPOSE: To determine whether hyperglycemia affects pancreatic islet microcirculation in vivo and whether nitric oxide is a mediator. METHODS: Islet blood flow was measured before and after infusion of glucose during in vivo microscopy of mouse pancreatic islet. The pancreas of male BALB/c mice was exteriorized and viewed under the microscope utilizing monochromatic transmitted light. The carotid artery and tail vein were cannulated and systemic blood pressure was monitored continuously. Under fluorescent light, a 0.02 mL bolus of 2% fluorescein isothyocyanate (FITC-albumin) was injected intra-arterially and the first pulse of FITC-albumin through an islet capillary was videorecorded. Following equilibration, either glucose or normal saline 300 mg/g of body weight was given intravenously. Five minutes later, a second bolus was given and the second pulse was videorecorded. The study was repeated in the presence of N omega-nitro-L-arginine methyl ester (L-NAME). The FITC-albumin bolus mean transit time (TT) and observed cross time (OCT) through the islet were calculated using slow-motion video analysis of the recorded images. RESULTS: Infusion of glucose resulted in a significant increase in islet blood flow with no change in systemic blood pressure: baseline TT was 20 +/- 1.3 pixel/0.03 sec and baseline OCT was 0.6 +/- 0.04 seconds; during hyperglycemia, TT was 16.1 +/- 1 pixel/0.03 sec, and OCT was 0.48 +/- 0.03 seconds (n = 11, P < 0.05 versus basal via paired t-test). Continuous infusion of L-NAME negated the effect of hyperglycemia on islet blood flow: baseline TT was 20 +/- 1.8 pixel/0.03 sec and OCT was and 0.6 +/- 0.05 seconds; during hyperglycemia, TT was 20 +/- 1.1 pixel/0.03 sec and OCT was 0.6 +/- 0.33 seconds (n = 10; P < 0.05 versus glucose via unpaired t-test).

[Dural carotid-cavernous fistula with uveal effusion syndrome]. / Fistule durale carotido-caverneuse avec syndrome d'effusion uvéale.

We report the case of a patient with a dural carotid-cavernous fistula. The examination showed a proptosis, a chemosis, an increased intraocular pressure and a choroidal detachment. The diagnosis was confirmed by arteriography. The treatment consisted of the embolisation of the feeders originating from the external carotid artery. The ocular improvement was only partial, but choroidal detachment regressed.

[Treatment of unilateral limbal stem cell deficiency syndrome by limbal autograft]. / Traitement du syndrome d'insuffisance en cellules souches limbiques unilatéral par autogreffe de limbe.

PURPOSE: To evaluate the improvement of the ocular surface after limbal autograft in patients with unilateral limbal stem cell deficiency related to chemical burns. MATERIALS AND METHODS: Limbal autograft was performed in five patients with unilateral limbal stem cell deficiency related to chemical burns. Thereafter, four patients underwent penetrating keratoplasty. The limbal graft was obtained from the fellow eye, and was secured with interrupted sutures. Patient follow-up ranged from 10 to 47 months. Limbus and corneas were studied by means of light microscopy. RESULTS: All five patients reported subjective improvement. Vascularization decreased in one cornea. Visual acuity improved in one eye and did not change in the remaining four eyes. After penetrating keratoplasty, graft reepithelialization was achieved after respectively 3, 4, 21, and 30 days. Light microscopy showed the presence of goblet cells in the limbal epithelium in four cases. After limbal autograft, the corneal epithelium was devoid of goblet cells in three out of four cases. CONCLUSION: Limbal autograft improves the ocular surface and the prognosis of subsequent penetrating keratoplasty in patients with unilateral limbal stem cell deficiency related to chemical burn.