Percutaneous coronary rotational angioplasty in humans: preliminary report.

Percutaneous coronary rotational angioplasty was attempted in 12 patients. The procedure was performed with a flexible rotating shaft with an abrasive tip, varying in diameter from 1.25 to 3.5 mm, tracking along a central guide wire. Among the 12 patients (mean age 58 years), 4 had a stenosis in the left anterior descending coronary artery and 8 a stenosis in the right coronary artery. After the guide wire crossed the stenosis, the abrasive tip was slowly advanced and several passes across the stenosis were made. The residual stenosis was measured with computerized automatic quantitative coronary angiography. Success was defined as a reduction of percent stenosis by greater than 20%. If residual stenosis remained significant (greater than 50%), the procedure was completed by balloon dilation. The device could not be inserted in 2 of the 12 patients. Five of the 10 patients underwent rotational angioplasty alone, and 5 had the procedure completed by balloon dilation. The stenosis was significantly enlarged from 0.56 +/- 0.31 mm to 1.26 +/- 0.28 mm. The outline of the vessel appeared smooth and regular. There were no complications related to the procedure and all patients were free of symptoms when discharged 2 to 3 days after the procedure. Thus, coronary rotational angioplasty is a simple and safe procedure allowing marked dilation of the narrowed segment. However, long-term follow-up is required for further evaluation.

XeCl laser in biliary calculus fragmentation: fluence threshold and ablation products.

The in vitro action of a xenon-chlorine (XeCl) excimer laser on biliary calculi is reported: fluence threshold and rate for ablation process are given. An analysis of gaseous products evolved during irradiation of gallstones, performed through an infrared spectrophotometric technique is also reported. Based on the different results, we discuss the mechanism of destruction.

A resource server for medical training.

OBJECTIVES: We have developed a RESOURCE SERVER to collect and store various elements used by a professor during his lecture. METHODS: The server manages four types of objects: ELEMENTS, RESOURCES (set of elements referring to a given topic), INDEXES (to organize the resources for further search and use), and USERS (to identify providers, users, and access rights). If an ELEMENT s modified, the RESOURCE is automatically updated. RESULTS: An example (preparation of an anatomy lecture) explains how the RESOURCE SERVER works in three steps: organization of the training material, indexing, and retrieval. CONCLUSIONS: The RESOURCE SERVER will help instructors develop, update and share pedagogic resources for supporting their training courses, lessons and conferences. Moreover, these techniques, based on Internet technologies for easy handling of and access to these resources, allow local and distant access. Within the general framework of the French-speaking Virtual Medical University, the RESOURCE SERVER will represent an important link between data collection and its use in intelligent pedagogic training.

The value of endoscopic retrograde opacification of biliary-pancreatic ducts in icterus.

Important progress in the last few years in fiberscopic instrumentation for digestive endoscopy has made possible duodenoscopy with catheterization of the papilla to obtain retrograde biliopancreatic contrast x-rays. Up to now the only possible way to explore biliary ducts, in icterus, was surgically. This new method makes their study possible without any surgical intervention and with a simple neuroleptanalgesia. It is most advantageous in icterus where clinical tests, laboratory tests and other complementary examinations such as laparoscopy do not help to determine the cause. This examination is not devoid of dangers, particularly of the risk of cholangitis and pancreatitis and therefore certain technical precautions are necessary, e.g., immediate surgical intervention in case of organ obstruction and well defined indications.

[Development and evaluation of a laser catheter with tip fiberoptic for coronary angioplasty]. / Mise au point et évaluation d'un cathéter laser avec fibre optique à boule pour angioplastie coronaire.

A fiber-optic tip catheter has been developed for treating coronary and peripheral atherosclerosis percutaneously. The catheter is coupled to an ionised Argon laser emitting at an optical power of 1 to 7 Watts. It is designed to follow a guide wire and to perform tissue ablation by a new concept combining the effects of central vaporisation and peripheral thermal remodelling of the obstructed artery. This mode of function should considerably reduce the risks of false route previously encountered with laser angioplasty. The optical and thermic properties of the catheter prototypes were determined by physical methods. These experiments showed that the temperature of the metallic component of the catheter tip did not exceed 30 degrees C at a continuous power of 6 laser Watts when the flush was functioning. It attained 400 degrees C in the absence of the flush. The performances of the catheter were then tested in a number of in vitro experiments. First of all, the catheter tip was placed perpendicularly to atheromatous cadaver aortae to study the effect of vaporisation with respect to the laser power. The threshold of vaporisation was 1 Watt (irradiance: 1100 Watts/cm2). The catheter was then introduced into plastic tubes obstructed by atheromatous plaques. This experiment demonstrated the mechanical solidity of the catheter and its flexibility in difficult operating conditions: diameter 2mm, 45 degrees angles, irregular calcified plaques. It also showed that the optimal safety-efficacy laser power was 3 laser Watts and that the exposure times varied with respect to the nature of the plaques tested.(ABSTRACT TRUNCATED AT 250 WORDS)

[A new method of laser angioplasty by contact sapphire: preliminary results. Apropos of 20 cases]. / Nouvelle méthode d'angioplastie laser par saphir de contact des artères périphériques: résultats préliminaires. A propos de 20 cas.

We report our first 20 cases of peripheral laser angioplasty using an optic fibre with contact sapphire tip. The equipment included a teflon catheter on which was screwed a round sapphire 2.2 mm in diameter. A 600 microns optic fibre connected to a Nd-Yag laser instrument was introduced into the catheter and placed in contact with the sapphire. Twenty patients underwent recanalization of femoral or popliteal arteries occluded on a length of 5 to 45 cm. The sapphire-tipped catheter was introduced by the Seldinger technique up to the site of occlusion. The 15 watt laser emission was set at intervals of one second. Sixteen out of the 20 occluded arteries were recanalized. Among the 4 failures, 3 were due to perforation and 1 to intraparietal progression. Angioplasty was performed with laser alone in 3 cases and with laser completed by balloon catheter in 13 cases. The minimum diameter of the laser-induced channel was 2 mm and was significantly increased (3.8 mm) by complementary balloon dilatation. In the 3 patients who underwent laser angioplasty alone, no noticeable improvement in distal blood flow was demonstrated by doppler velocimetry, and reocclusion occurred either soon afterwards (n = 2) or later (n = 1). Midterm results were much better in patients who had had additional balloon dilatation: early (3rd day) or late (2 months) reocclusion took place in only 3 patients. In the remaining 10 patients, followed up for periods of 1 week to 18 months (mean: 6 months), clinical improvement and recanalization were maintained.

[Palliative treatment of cancer of the esophagus and cardia by laser photo-ablation]. / Traitement palliatif des cancers de l'oesophage et du cardia par photoablation laser.

The results of the palliative treatment by laser photo-ablation for esophageal and gastric cancers in 79 nonsurgical patients are reported. The aim of treatment was to relieve dysphagia in 60 patients with an obstructive tumor, to maintain esophageal lumen patency in 8 patients with a nonobstructive tumor, and to completely destroy 11 small tumors. The success rate in the patients with dysphagia was 78 p. 100. Functional improvement lasted as long as patients survived with further treatment required once or twice a month. The best results were obtained in exophytic, non circumferential lesions, and in adenocarcinomas of the esophagogastric junction. The localization at the upper third of the esophagus was associated with poor prognosis. The complication rate was 6.6 p. 100. Eight of the 11 small lesions were completely destroyed, but radiation therapy had been associated in four cases with invasive cancer, one of which recurred after 6 months. No complications occurred in this last group of patients.

[Gastric metastasis of a malignant melanoma of the choroid]. / Métastase gastrique d'un mélanome malin de la choroïde.

Gastric metastases of choroid malignant melanoma seem to be exceptional since less than 10 cases have been previously published. We report the case of a 71 year old patient with a gastric melanosarcoma secondary to a choroid malignant melanoma. Gastric metastasis was revealed by digestive bleeding occurring 18 years after right eye enucleation. Gastroscopy showed black ulcerated tumors. Histology confirmed the diagnosis portraying typical melanic pigments within the gastric mucosa. Laser photocoagulation of the gastric lesion was used for the first time in this indication. As a result, hemorrhage decreased and the patient's comfort was improved.

[Blue rubber bleb nevus syndrome. 3 cases treated with a Nd:YAG laser and bipolar electrocoagulation]. / Blue rubber bleb nevus syndrome. Trois cas traités par laser Nd:YAG et électrocoagulation bipolaire.

This report concerns three patients with "blue rubber bleb nevus syndrome" presenting with recurrent digestive tract hemorrhage. Tuberous angiomas of the digestive tract associated with typical skin lesions as described by Bean led to diagnosis. Endoscopic coagulation with Nd:YAG laser and bipolar electrocoagulation "Bicap" of gastric and colonic angiomas was performed successfully without complication but did not avoid hemorrhagic recurrence originating from lesions located in the small bowel, as demonstrated during laparotomy in one case.

[Laser treatment of rectosigmoid villous tumors. Study of a series of 313 patients]. / Traitement par laser des tumeurs villeuses rectosigmoïdiennes. Etude d'une série de 313 malades.

Endoscopic laser treatment is reported in 313 patients with benign rectosigmoid villous adenomas. Total tumor destruction was achieved in 92% of them, without any major complications. The circumferential extension of the tumor base was the only factor affecting this result. During the average 37-month follow-up period of the patients with total tumor destruction, 14% had a tumor recurrence. The recurrence rate after initial treatment was higher a) in patients treated for a recurrence after a previous non laser treatment, b) when the initial histology was low-grade dysplasia and c) when the tumor was located in the lower or middle rectum. Because treatment is long and difficult with a high cancer rate, laser treatment for patients with a circumferential villous adenoma should be limited to nonsurgical candidates. In the other cases, laser is well adapted to old and fragile patients, when transanal resection seems difficult or in case of recurrence after a previous non-laser treatment.

[Control of intensity of light coagulation by thermo-induced release of a fluorescent marker encapsulated in liposomes. In vivo/ex vivo preliminary study]. / Contrôle de l'intensité des photocoagulations par libération thermo-induite d'un marqueur fluorescent encapsulé dans des liposomes. Etude préliminaire in vivo/ex vivo.

PURPOSE: The aim of this in-vivo/ex vivo study was to assess the possible use of temperature sensitive liposomes in an established model such as the liver as a new approach to monitor the temperature induced by a laser. METHOD: Temperature sensitive liposomes (DSPC: DiStearoylPhophatidyl-Choline: critical temperature: 55 degrees C) loaded with carboxy-fluoresceine were prepared by the Bancham procedure. These liposomes (1 ml solution) were injected to adult male wistar rats. Two hours later, the liver was exposed and irradiated with a 100 W Nd: YAG laser (single pulse mode, pulses ranging from 100 to 260 ms, spot diameter: 4 mm). Simultaneously, the surface temperature was recorded with a infrared thermographic camera (Aga). The fluorescence emission was then measured with a fluorescent imaging system (Hamamatsu). RESULTS: The dye was released in response to laser energy. The amount of the drug release increased linearly with increasing temperature in the range 42 to 60 degrees C. The estimated latency of release seems more related to the heating pattern (i.e. to laser parameters) than to the liposomes. CONCLUSION: This preliminary study assesses the possible use of laser-induced release of liposome-encapsulated dye to monitor tissue temperature and then thermal damage.

[Proximal tubal recanalization by endoluminal laser probe. I. Anatomic results in the female rat]. / Recanalisation tubaire proximale par sonde laser endoluminale. I. Résultats anatomiques chez la rate.

To evaluate the cicatrization of the uterine horn after the recanalization by endoluminal laser probe, 50 white female rats of Wistar's race have been separated into two groups. The group 1 (nb = 10) had for aim to validated the procedure of obstruction. In group 2 (nb = 40), we performed the recanalization six weeks after the obstruction. Histologic samples were obtained 48 hours, 3 weeks and 6 weeks after treatment. In group 1, we found a complete obstruction in 70% of the cases, and a tight stenosis in 30% of the cases. In group 2, at 48 hour's control after the treatment by laser, we found a drill hole with a blackened look without parietal sequel in 80% of the cases. At 6 week's control, we found a normal lumen with a regeneration of the epithelioma in 85% of the cases. For energy deposition under 30 Joules, we found good results in 95% of the cases. Above 30 Joules, we always found bad results (5 cases on 5).

[Proximal tubular recanalization by endoluminal laser. II. Functional results in the female rabbit]. / Recanalisation tubaire proximale par sonde laser endoluminale. II. Résultats fonctionnels chez la lapine.

To evaluate the function of the fallopian tube after a recanalization by endoluminal laser probe, 34 mature female New Zealand white rabbits have been separated into two groups. The group 1 (nb = 12) had for aim to validate the procedure of obstruction. In group 2 (nb = 22), we performed the recanalization six weeks after the obstruction. The female rabbits underwent a fertilization six weeks after the laser treatment. The results have been appreciated by the ratio nidation/ovulation. In group 1, we valided the procedure of obstruction. In group 2 twelve rabbits on thirteen have been fecundated in the treated tube.

Impact of a modelization of the task allocation problem on the design of a prescription management software for intensive care units.

After having studied the coordination in Intensive care Units we have proposed a dynamic model for improving coordination in respect of human control over the work. We have performed simulations for analysing the impact of different strategies on coordination and we have found that our task centred coordination model could be efficient to improve the health care actors coordination and the efficiency of care delivery. We have built a first prototype based on this model. This implementation uses Internet technologies.

The French Virtual Medical University.

This paper is the description of a French Virtual Medical University based on the federation of existing or currently being developed resources in several Medical Schools in France. The objectives of the project is not only to share experiences across the country but also to integrate several resources using the New Information and Communication Technologies to support new pedagogical approaches for medical students and also for continuing medical education. The project includes: A virtual Medical Campus using secure access from several sites, The Integration of new interactive resources based on pedagogical methods, Implementation of new indexing and search engines based on medical vocabularies and ontologies, The definition of general and specific portals, the evaluation of the system for ergonomics and contents.

[Laser in dermatology: biological effects; indications (author's transl)]. / Les lasers en dermatologie: effets biologiques - indications thérapeutiques.

The various laser-systems can be classified according to: 1) the wavelength or range of wavelengths of the beam and 2) the method of delivery of the laser output: continuous or pulsed. -- Principal continuous-wave lasers are: -- the argon-ion laser, which produces multiple transitions ranging from 448 to 544 nm, -- the neodymium yttrium aluminium garnet (Y. A. G.) operating in the near infrared at a wavelength of 1,060 nm, -- and the carbon-dioxide laser with its output occurring in the far infrared, at 10,600 nm. Continuous-wave lasers induce essentially thermal effects which are used to coagulate or volatilize various superficial skin lesions. But when high power density is required, the relative benefit of lasers as compared with other conventional thermal devices (such as high-frequency electrocoagulator) is not obvious. On the other hand, the argon laser is capable of selectivity damaging pigmented cutaneous lesions with satisfactory healing of the laser wound and sparing of the overlying skin. This selective absorption is useful in the treatment of some vascular lesions such as port-wine stain or melanotic lesions or tattoos, and gives a good results. The specific color absorption is not so pronounced with the Nd-YAG laser and is absent with the carbon dioxide laser, chiefly used as an "optical scalpel". Photochemical effects produced by other continuous-wave lasers such as U.V. lasers, seem to be of interest in photobiology research and in destruction of tumors after the addition of a colorant. -- Pulsed laser systems produce not only thermal but also "non-linear" reactions, which are not well-known. The classical ruby laser is still appropriate in the treatment of some skin lesions.

[Physical basis of therapeutic uses of lasers]. / Bases physiques des applications therapeutiques des lasers.

Therapeutic applications of lasers usually require different mechanisms of laser tissue interaction: the thermal interaction mechanism where light energy is converted into heat, the photochemical interaction mechanism where light induces chemical reactions, the mechanical interaction mechanism where light produces shock wave and the photoablative interaction mechanism where light energy produces desorption of tissue. The interaction mechanism depends on the choice of the laser parameters.

[Future of medical lasers]. / L'avenir des lasers médicaux.

Whatever the medical field of application of lasers, their future is linked to research and to the realization of systems of automatization which will allow the development of "smart lasers". It will be linked to the improvement of imaging techniques and of medical computers, as well as to the development of new feedback systems; the wavelength and the laser beam dosimetry could then be automatically chosen depending on the aimed tissue and on the biophysical effect desired on the target (coagulation, vaporization, cutting, hyperthermia, photo-ablation). Practically, the future of lasers also depends on the elaboration of new peripheric systems and a better conception of new laser equipment. At last, clinical evaluation of such new surgical technologies with well adapted procedures, formation and information through specific teaching courses and seminars will help to the development of all new laser-technologies.

[The 1.320 micron Nd-YAG laser. Experimental study of a new wavelength adapted to neurosurgery]. / Le laser Nd-YAG 1,320 micron. Etude expérimentale d'une nouvelle longueur d'onde adaptée à la neurochirurgie.

The authors present a new laser wavelength for neurosurgery: the 1.32 micron Nd-YAG laser. Schematically, it combines the advantages of both the 1.06 micron Nd-YAG laser and the CO2 laser. As for nervous tissue it has the same physico-thermal properties as the CO2 laser: an important absorption and little thermal diffusion. Like the 1.06 Nd-YAG laser, the 1.32 Nd-YAG has very good maneuverability, because its beam is conducted through optical fibers. Experimental studies have been made on rats. They consisted of comparison between the thermal effects and the consequent histological lesions of three lasers: 1.32 micron Nd-YAG, 1.06 micron Nd-YAG, CO2. 145 impacts on the cortex of 45 rats have been studied. Each shot was registered with an infrared camera, measuring the cortex surface temperature around the impact. The signals were digitalized; they allowed us to obtain a numerical image and the profile of temperature for each shot, as well as the development of temperature of each point of the profile. These results have been correlated with the histological data. It appears that for equivalent efficient outputs, the cortical lesions, 8 days after the shots, were similar for the 1.32 Nd-YAG laser and the CO2 laser. For instance, the depth of the coagulation necrosis varied from 200 to 250 microns after CO2 laser impacts (P = 3W; t = 0 05s; Fluence = 5 Joules/cm2), and from 210 to 260 microns after 1.32 Nd-YAG laser impacts (P = 5-14W; t = 0.4s; F = 50-170 J/cm2).(ABSTRACT TRUNCATED AT 250 WORDS)