[Composition of 359 kidney stones from the East region of Algeria]. / Détermination de la composition de 359 calculs du haut appareil urinaire collectés dans la région Est-algérien.

PURPOSE: Determine stones composition of the upper urinary tract in the eastern region of Algeria. METHODS: Our study focuses on a set of 359 stones of the upper urinary tract collected between January 2007 and December 2012 at hospitals in the eastern region of Algeria and analyzed by Fourier transform infrared spectroscopy. RESULTS: The male/female ratio was only 1.32. Calcium oxalate prevailed in 68.5% of stones and 49.3% of nuclei, mainly as whewellite (51.8% of stones and 37.9% of nuclei vs 16.7% and 11.4% respectively for weddellite). Carbapatite prevailed in 15% of stones and 29.8% of nuclei. The struvite, identified in 11.1% of calculi, prevailed in 3.9% of stones and 3.1% of nuclei. Among purines, uric acid prevailed with frequencies quite close to 8.9% and 7% respectively in the stone and in the nucleus while the ammonium urate prevailed in only 0.3% of stones and 3.3% of nuclei. The cystine frequency was 3.6% in both stone and nucleus. The frequency of stone with umbilication was 26.2%. Whewellite was the main component of umbilicated stones with Randall's plaque. CONCLUSION: Our results suggest that stones of the urinary tract in the Algerian east region resemble those observed in industrialized countries. Some features such as stones location, the whewellite prevalence, the frequencies of main components in both the stone and the nucleus as well as the formation of stones on renal papilla confirm this trend. LEVEL OF EVIDENCE: 4.

Polyelectrolyte multilayer film and human mesenchymal stem cells: an attractive alternative in vascular engineering applications.

Mesenchymal stem cells (MSCs) have tremendous potential as a cell source for regenerative medicine due to their capacity for differentiation into endothelial-like cells when seeded on nonmodified cover glasses. This absence of removable surface, preventing recovery of cell sheet, constitutes a critical obstacle to predict an application in tissue engineering. It remains unknown whether MSCs differentiation could be realized when the cells are cultivated on a scaffold that could be used in vascular engineering. In this study, we propose to differentiate human MSCs into endothelial-like cells on surfaces coated with polyelectrolyte multilayer film (PMF) and fibronectin (control surfaces). We quantified Platelet Endothelial Cell Adhesion Molecule (PECAM) and von Willebrand Factor (vWF) expressions (endothelial cell specific markers) and nitric oxide (NO) production, which is representative of the cell functionality. After only two weeks of differentiation, we showed, on PMF, that MSCs expressed PECAM and vWF, exhibiting a differentiation into endothelial-like cells, which functionality was explored by a significant production of nitrites. These results highlight the importance of PMF to get human MSCs differentiation and suggest that this film of nanometer thickness opens a new route for vascular bioengineering by pre-seeding hMSCs directly into a vascular graft functionalized by a removable coating.

Mechanical valve dysfunction in yemen.

BACKGROUND: Rheumatic heart disease is the most common cardiac disease in Yemen. It is associated with high morbidity and mortality. Valve replacement is the most common open heart surgery procedure in our cardiac center. The use of mechanical valves remains burdened with serious complications such as thrombosis. Valve thrombosis is still associated with high mortality(]) The reported mortality rate of the redo operation ranges from 8 to 20% and up to 37-54% in critically ill patients. OBJECTIVE: The aim of the present study was to investigate mechanical valve obstruction among Yemeni patients. PATIENTS AND METHODS: Between January 2003 and April 2007, 2794 patients underwent prosthetic valve replacement in our center, Al-Thawra Hospital. Of those patients, 129 (4.6%) underwent reoperation for te obstructive mechanical valve. Patients with clinical suspicion of prosthetic valve obstruction (PVO) were admitted emergently to the CCU and the diagnosis was confirmed with echocardiography. All patients had heart failure; 95% of them were in NYHA class IV. All were transferred directly from the CCU to the operating room. The mean age was 34.8 ± 13.4 years. Two patients received preoperative thrombolytic therapy that was not successful. Obstruction involved the mitral valve prosthesis in 47 (36.4%); the aortic prosthesis in 16 (12.4%) patients; both valves in 21 (16.3%) patients; mitral valve replacement with tricuspid valve repair in 22(17%); double valve replacement with tricuspid valve repair in 1 (0.8%); redo mitral valve replacement with aortic valve cleaning in 7 (5.4%) cases; aortic valve cleaning in 5 (3.9%) patients; mitral valve cleaning in 5 (3.9%); and 5 (3.9%) patients had redo mitral with aortic replacement. RESULTS: The operations were performed urgently. The etiology of the obstruction was thrombus in 111 (86%), pannus formation in 4 (3%), pannus and thrombus in 6 (4.8%), vegetation in 7 (5.4%) patients, and interposition of suturing materials in 1 (0.8%) patient. The in- hospital mortality was 23/129 (17.8%). CONCLUSION: The incidence of prosthetic valve obstruction remains high in Yemen. The vast majority of the patients who are referred to our hospital come from remote provinces in the country where regular INR measurement is not readily available. For those who are living in areas without good medical care, certain measures are necessary to avoid this disastrous complication: (1) good patient education, (2) free INR testing and free anticoagulant drugs such as warfarin; and (3) use of tissue rather than mechanical valves.

[Is power Doppler US a good predictor of prostate cancer aggressiveness]. / L'écho-Doppler puissance est-il un bon témoin de l'agressivité du cancer de la prostate?

PURPOSE: To determine the value of Power Doppler US for the diagnosis of prostate cancer and in the prediction of cancer aggressiveness. PATIENTS AND METHODS: One hundred and five consecutive patients with PSA>4 ng/ml and/or abnormal digital rectal exam underwent power Doppler US prior to biopsy. In addition to biopsies directed to suspiscious lesion on US, 10 to 12 standard sextant biopsies were obtained. Histologic results were correlated to imaging findings. RESULTS: A hypervascular lesion (enlarged, irregular, serpentine or disorganized vessels) was present at power Doppler US in 34 patients and corresponded to cancer in 28 cases. Nineteen cancers showed no detectable abnormality on power Doppler US. Cancer was present in 271 of 1093 cores. After correlation with results from sextant prostate biopsy, power Doppler showed a sensitivity of 44%, specificity of 96%, positive predictive value of 84% and negative predictive value of 80%. Positive results on power Doppler US were strongly cotrrelated with higher Gleason scores. CONCLUSION: Power Doppler US may contribute to the evaluation of prostate cancer aggressiveness and direct biopsies to more aggressive foci.

Polyelectrolyte multilayer films: effect of the initial anchoring layer on the cell growth.

In tissue engineering, surface characteristics of a biomaterial are one of most important factors determining the compatibility with the environment. They influence attachment and growth of cells onto the material. In many cases, the surface should to be modified and engineered in the desired direction. The modification of non-adhesive surfaces with polyelectrolyte multilayer films (PMF) was recently depicted as a powerful technique to promote the growth of different cell lines. In this study, we evaluated the possible use of two different PMF as surface modification for the culture of mesenchymal stem cells (MSC). We used two types of PMF which differed by the nature of the initial anchoring layer which was poly(ethylenimine) (PEI) or poly(allylamine hydrochloride) (PAH). This initial polyelectrolytes adsorption was followed by the alternated deposition of poly(sodium 4-styrenesulfonate) (PSS) and (PAH) in order to obtain a PEI-(PSS-PAH)(3) film or a PAH-(PSS-PAH)(3) film. In order to control the behaviour of MSC, the cell viability was evaluated by Alamar Blue assay and the actin cytoskeleton was labelled and visualised in a confocal microscope. The behaviour of cells on the two PMF was compared to cells cultivated on surfaces treated with fibronectin. The results showed that PAH-(PSS-PAH)(3) PMF improve the growth of cells, inducing a higher cell viability compared to PEI-(PSS-PAH)(3) PMF and fibronectin at 2, 3 and 7 days of culture. Moreover, those cells showed a well-organized actin cytoskeleton. In conclusion, PAH-(PSS-PAH)(3) polyelectrolyte multilayer film seems to constitute an excellent material for MSC seeding.

Effects of renal diseases on the regulation and expression of renal and hepatic drug-metabolizing enzymes: a review.

1. The activity of drug-metabolizing enzymes (DMEs) in extrahepatic organs is highest in the kidneys. Generally, the kidneys contain most, if not all, of the DMEs found in the liver. Surprisingly, some of these DMEs show higher activity in the kidneys than in the liver. 2. Most of the renal DMEs are localized in the cortex of the kidneys, especially in the proximal tubules. DMEs are also found in the distal tubules and collecting ducts. 3. Renal diseases such as acute and chronic renal failure and renal cell carcinoma alter the regulation of both hepatic and extrahepatic phase I and II DMEs. Changes in the expression of these DMEs seem to be tissue and species specific. 4. Generally, there is significant down-regulation of most of the phase I and a few of phase II DMEs at the protein, mRNA and activity levels. Unfortunately, the mechanisms leading to the alteration in DMEs in renal diseases remain unclear, although many theories have been made. 5. The presence of some circulating factors such as cytokines, nitric oxide, parathyroid hormones and increased intracellular calcium play a role in the regulation of DMEs in renal diseases.

[Glaucoma and ocular hypertension: the importance of intraocular pressure in treatment decisions in France]. / Glaucome et hypertonie oculaire: importance de la pression intraoculaire cible dans la prise en charge thérapeutique en France.

PURPOSE: Several recent clinical studies have shown the benefit of lowering intraocular pressure in both ocular hypertensive and glaucoma patients. However, in patients with open-angle glaucoma (OAG) or ocular hypertension (OHT), there is no consensus on the value of intraocular pressure (IOP) to be reached to prevent the progression of visual field defects. This IOP value, called target IOP, is defined by the ophthalmologist according to the patient and the progression of the disease, without a clear explicit justification of this decision. In France, ophthalmologists' education is mainly based on scientific meetings and the European Guidelines. This study was conducted to investigate the position of the IOP target in the treatment strategy for patients with glaucoma or OHT. MATERIAL: and methods: A cross-sectional descriptive survey was conducted in France among ophthalmologists in private practice. Patients with simple OHT or with OAG who required an initiation or a modification of treatment were included. RESULTS: We included 1735 patients (805 males, 46.4%) in the study. An OAG was diagnosed in 1338 patients (77.1%) and a simple OHT in 397 patients (22.9%). The patients with OAG were older than the OHT patients (65 years vs 61.7 years, p<0.0001). Most patients (73.5%) were included for treatment modification (77.5% of the patients with OAG and 59.9% of the patients with simple OHT; p<0.0001). The main reason for treatment change was an unsatisfactory IOP value. The main therapeutic objective was to reach a target IOP in 46.0% of the patients. The choice of the ocular hypotensive drugs depended on the IOP value in 51.9% of the patients. When the treatment was modified, monotherapy was preferred in 60.8% of the patients. CONCLUSION: Among ophthalmologists, the main objective for the treatment of patients with simple OHT or with OAG was to reach a target IOP. About half the participants were used to set up a target pressure for their patients. This fairly good ratio shows the comprehensiveness and the adaptation of our colleagues to relatively new concepts in treating and managing patients with ocular hypertension or chronic open-angle glaucoma. If a modification in the treatment was necessary, then monotherapy was preferred. This decision was motivated by the efficacy of the treatment but also by expected better patient compliance.

Cytochrome P-450 content and activity after cold storage of rat hepatocytes in university of wisconsin and sodium-lactobionate-sucrose solutions.

We compared the capacity of University of Wisconsin (UW) and of sodium-lactobionate-sucrose (SLS) hypothermic preservation solutions to maintain the integrity of the hepatic cytochrome P-450-dependent mono-oxygenase system. Isolated rat hepatocytes were stored for 0, 10, 24, and 48 hours in UW or SLS solution and were subsequently cultured shortly at 37 degrees C. Cell viability declined slightly but significantly in a time-dependent manner during cold preservation in either UW or SLS solution, and warm culture exacerbated this effect. Total cytochrome P-450 declined gradually after cold preservation and warm culture to reach values of 70% and 52% of unstored controls in cells preserved for 24 and 48 hours in cold UW solution, respectively. Storage in cold SLS solution yielded a similar decrease to 79% and 59% of unstored controls for the equivalent preservation times. Cytochrome P-450 activity was assessed by the metabolism of theophylline after various cold preservation times in UW or SLS solutions. Production of the major metabolite 1,3-dimethyluric acid was not significantly affected by extended cold preservation periods in either UW or SLS solutions. Similarly, the amount of residual theophylline remained stable in all groups, suggesting that alternative metabolic routes were not modified. These studies show that cold preservation in SLS solution is as effective as that in UW solution in terms of cell viability, cytochrome P-450 content, and activity toward theophylline. In addition, the significant reduction in cytochrome P-450 in conjunction with unaffected theophylline disposition suggests that certain cytochrome P-450 isoforms are specifically damaged by cold preservation and rewarming.

Functional reconstitution of membrane glycoproteins into lipid vesicles using lectin precipitation. Application to the VIP receptor.

We studied the interaction of n-octyl-beta-d-glucopyranoside-solubilized VIP receptors (VIPR) with wheat germ agglutinin and found that the addition of the lectin to the detergent extract led to the formation of aggregates that could be pelleted by high speed centrifugation. Resuspension of the pellet in the presence of the competing trisaccharide, N,N', N"-triacetylchitotriose (TAC), dissociated the lectin from the complex without altering the precipitability of VIPR. The final pellet (referred to as TAC pellet) contained an average of 12% of total protein and 96% of total VIP binding activity with a typical rank order of potency for VIP-related peptides. Lipid analysis and electron microscopic examination indicated that the precipitated material was composed of lipid vesicles. VIPR molecules were shown to be integrally inserted in the liposomes because they could not be dissociated from the vesicles at pH 11 or with high salt concentration. By comparing the liposome-associated VIP binding activity in the presence and absence of detergent and by showing accessibility of VIPR to PNGase F, it was concluded that VIP binding sites were not simply trapped within the reconstituted vesicles but likely exposed at the external surface of the liposomes.

Effect of microtubule disruption on cell adhesion and spreading.

Microtubules have been involved in a variety of cellular processes. In this study, we examined the role of the microtubular system in the adhesion and spreading of the adenocarcinoma cell line HT29-D4. Disruption of microtubules by nocodazole or navelbine resulted in an increase in cell adhesion to purified ECM proteins. This enhanced cell adhesion is mediated by integrins, but is not attributable to quantitative changes in the number of integrin receptors at the cell surface, as determined by flow cytometric analysis. In contrast to attachment, spreading of HT29-D4 cells was reduced by nocodazole treatment in a dose-dependent manner. Thus, microtubule depolymerization appears to increase initial attachment of cells to extracellular matrix, while impeding subsequent cell spreading.

Study of the Gelation Process of Polyethylene Oxidea -Polypropylene Oxideb -Polyethylene Oxidea Copolymer (Poloxamer 407) Aqueous Solutions

The gelation process of polyethylene oxidea -polypropylene oxideb -polyethylene oxidea copolymer (poloxamer 407) aqueous solutions is studied by means of FTIR spectroscopy, rheology, and differential scanning calorimetry (DSC). The C-O-C stretching bands of infrared spectra were found to shift toward higher wavenumbers with sol-gel transition, indicating that hydrogen bonding is not the driving force for gelation. Linear viscoelastic data provide an alternative method for gel point determination of these thermoreversible gels. The results obtained with this method are found to coincide with those obtained using DSC. Gel point temperatures determined by these methods are close to 14 degrees C for 25% (w/w) poloxamer 407 solutions and 10 degrees C for 30% (w/w) solutions. In gel state, the elastic modulus (G ') and dynamic viscosity (eta*) are found to be concentration and temperature independent for temperatures ranging from 20 to 35 degrees C. In light of our results, we suggest a mechanism of gelation based on micelles packing and entanglements.

Interactive image guidance in skull base surgery using an opto-electronic device.

The applicability of an image guidance frameless system based on an opto-electronic sensor device in skull base surgery was explored in this study. Five embalmed heads with external fiducial markers placed in noncoplanar points were scanned (CT scan) and different skull base approaches were reproduced in these specimens. The opto-electronic system is comprised of an infrared camera, a local rigid body, and a 24-light-emitting diode probe attached to different surgical instruments. DOS-based calibration and transformation software and Unix-based surgical planning software were also used. The anatomic landmarks identified during the dissection were matched with the corresponding points derived from computed tomographic (CT) scans. This information allowed the surgeon to develop a three-dimensional representation of the surgical field and to anticipate the next anatomic structure encountered during the dissection. This infrared device operated in real time, is not affected by external factors with regard to its accuracy, and does not interfere with standard neurosurgical techniques. This frameless system is helpful in minimizing the risk of morbidity and provides an accurate guide during the approach, as well as unobstructed access to the surgical field.

Computer-assisted neurosurgery system: Wayne State University hardware and software configuration.

Computer-assisted neurosurgery uses the latest technological advancements in imaging, computers, mechanics, and electronics to improve the accuracy and reduce the invasiveness and risk of neurosurgical procedures. We describe the Wayne State University, Detroit, Michigan, computer-assisted neurosurgical system with the emphasis on software and discuss the theory guiding the development of this system and its application in real-time position tracking systems. Our system consists of the Neurological Surgery Planning System (NSPS) software which we developed at our medical center and three types of position tracking systems: the Zamorano-Dujovny (Z-D) are digitizer for frame-based procedures, an articulated arm, and an infrared-based digitizer for frameless procedures. The NSPS software is designed to offer neurosurgeons a safe and accurate method to approach intracranial lesions by preoperatively planning a surgical trajectory. Software consisting of the most advanced technologies in computer vision, computer imaging/graphics, and stereotactic numeric analysis forms the core of the system. Capabilities for correlating data from imaging studies to facilitate image reconstruction, image mapping, and three-dimensional (3D) visualization of target volumes enable the neurosurgeon to simulate surgical procedures into a preoperative protocol to be used during surgery, both to follow the preplanned trajectory and to track the position of surgical instruments in real-time on the computer monitor. The tracking systems position and orient the surgical instruments relative to the patient's head. With these devices, the display of the surgical instruments together with the virtual images create an excellent intraoperative tool.

Interactive intraoperative localization using an infrared-based system.

Conventional stereotactic surgery has evolved from a ring-based system with a simple software which calculated few parameters to frameless intraoperative localization systems that provide the surgeon with real-time localization and correlation with several imaging modalities. The localization system described in this paper is an opto-electronic system that uses infrared emitters and three precalibrated CCD cameras. The system was chosen among others for the following reasons: it tracks target points defined by up to 256 miniature light emitting diodes, and its accuracy in locating the spatial position of a diode marker in the operating volume 1.0 x 1.0 m at a distance of 2.0 m is 0.1 mm with a resolution better than 0.01 mm. Systems like this one can track and define the position and orientation of any object in the field view of the camera. This is done by attaching a few small infrared emitters (light emitting diodes) to the surface of each 'rigid body' (surgical instrument) being tracked. Subsequently, through a calibration process a corresponding rigid body file is created. This rigid body file represents this particular object (i.e. surgical tool, microscope) and defines a local coordinate system that identifies each translation and orientation of that tool with respect to the camera coordinate system. This in turn is transferred into the computed tomographic/magnetic resonance imaging coordinate system by a process referred to as coordinate matching. Fiducial markers are placed on the patient's head prior to image scanning.(ABSTRACT TRUNCATED AT 250 WORDS)

Interactive intraoperative localization using an infrared-based system.

We discuss new methods of localizing and treating brain lesions for both the conventional method of a base-ring fixed to the patient's skull (referred to as frame-based procedures) and the new method of frameless procedures (no base ring). Frame-based procedures are used for finding a precise instrument position during neurosurgical procedures, such as stereotactic biopsy of deep-seated lesions, placing electrodes for functional stereotaxis or catheters with radioactive seeds for brachytherapy, or even the placement of a stereotactic retractor or endoscope for removal or internal decompression of lesions. In such procedures, the intraoperative image localization of instruments becomes useful as it tracks instruments as they travel through the preplanned trajectory. Additional intraoperative digitization of surgical instruments, e.g., bipolar suction, biopsy forceps, microscope, ultrasound probe, etc, can be achieved during the stereotactic resection of eloquent areas or deep intracranial lesions by adding an infrared-based system. Frameless procedures broaden the range of surgical approaches, image guidance planning, and operative procedures, since no ring is attached to the patient's head which might interfere with the surgical approach, and offers logistic advantages in scheduling diagnostic studies. Frameless diagnostic studies employ anatomical markers and/or surface matching techniques for data registration in the computer software surgical preplanning program. This simplifies scheduling of the procedures since the image study does not need to be acquired the same day as surgery. Frameless diagnostic studies allow for the use of more than one type of imaging data for planning and optimization of surgical procedures, and greatly improve patient tolerance and comfort during these procedures and during surgery, as compared with frame-based procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer-assisted neurosurgery: simulation and automation.

Instrumentation has been developed to automate, accurately guide, and integrate microsurgery laser resection equipment that is used in stereotactic brain surgery. The instrument is a computer-controlled laser-guiding system. The improvement in the accuracy comes from relying on a certain well-referenced three-dimensional surgical orientation, and computer-preplanned tumor contours, rather than only the surgeons hand-eye orientation in the operating room.

[Difficulties of radiologic diagnosis of renal masses. A case of hemangioma of the kidney]. / Difficultés du diagnostic radiologique des masses rénales. Une observation d'hémangiome du rein.

One case of renal hemangioma is reported. Exact diagnosis was dependent on histopathologic findings. This hemangioma had a calcified mass feature, so, several radiological diagnosis are debated. The relevant literature is reviewed.