Biomedical subjects
Publications and source records attributed to R Vignes.
The goal of this paper is to propose an algorithm based on the k nearest neighbours to compute a local predictability measure in biological sequences. Some ideas about the usefulness of this measure are discussed on the basis of preliminary experimentations.
The diagnosis of hereditary retinal syndromes may be difficult for a physician because of their number and variability. A computer assisted diagnosis of these syndromes can be useful in such cases. We used an identification software (XPER) for this purpose. The data base contains more than 67,000 elementary data that enable us to define 115 hereditary retinal syndromes. The knowledge is not represented by description of typical cases or diagnostic procedure rules but by structured description of syndromes defined by the group of experts. This CAI software is characterised by specific optimising procedures, deductive algorithms and dissimilarities calculus and enables very fast diagnoses by limiting the number of complementary analyses and thus the cost of this research. This system is extensible and justifies all its conclusions, its user-friendly data representation makes it accessible for any physician even if he does not master computers. The selected pathology field seems very suitable to developing a computer assisted diagnosis system: many low frequency syndromes, meaningful precise diagnosis for genetic and professional counseling, therapeutic expectations due to progress in molecular genetics. According to the authors, HERETAIN is one of the largest computer assisted decision support systems in ophthalmology.
We study the information included in sandfly wings in order to test this organ as a source for the specific discrimination. The cartesian coordinates of the vein intersections are collected using a microscope and a graphic table. From these data a specifically developed software searches for discriminant characters. The present study on 32 New World species shows that, in addition to classical wing indices, discriminative characters are available for inter-specific discrimination.
In the case of a conscious man suffering from a painful injury in the facial and trigeminal nerves, the administration of intra-muscular injections of increasing doses of morphine and sulfentanil provokes constant analgesia in direct proportion to the administered dose. The admitted dosages for each product are as follows. M = 0,100, 0,150, 0,200 mg/kg S = 0,00015, 0,0003, 0,0006 mg/kg. Sulfentanil is a highly active analgesic whose activity is about 333 times greater than that of morphine and 13 times greater than that of fentanyl. In the case of each of the 3 products, the point at which analgesia becomes clinically discernable is the same. Optimum intensity of action of the analgesia is arrived at in all 3 cases within a period of 60 to 90 minutes. The higher the dose administered, the longer sulfentanil can be expected to work. Although effective for a shorter period of time than morphine and fentanyl sulfentanil effectiveness is too great for it to be considered a short-acting analgesic.
For the purposes of this study, sulfentanil is administered to conscious men in increasing doses (0,00015, 0,0003, 0,0006 mg/kg) by intra-muscular injection, and the results are compared with those obtained in the same condition by administration of morphine (0,100, 0,150, 0,200 mg/kg). The administration of both drugs provokes the same side-effects. The failure of the breathing rate is as fast as observed following the administration of morphine in equi-analgesic doses. As in the case of analgesia, the time taken for the falling off of the breathing rate to occur, and its duration are shorter with sulfentanil, than with morphine. In any case their persistence is too great for one, to be able to consider sulfentanil as a drug of very short-term effect. The effects of sulfentanil on the cardiac rhythm (bradycardia) and on arterial pressure (low blood pressure) are slightly less intense, but above all, much shorter than that of a equi-analgesic dose of morphine. The other side-effects which are clinically discernable, particularly those felt by the patient, vomiting and changes in behaviour patterns are minimal; certainly lesser after administration of S than after tha of M. The sedative value are the same and often identical after administration of both drugs. Finally, the euphoric effect of sulfentanil appears to be slighter than that of morphine.
Fentanyl citrate is administered intramuscularly at increasing doses to patients suffering from an intense pain in the facial or trigeminal nerves territory. Fentanyl induces a very intense analgesia which develops during the hour following the administration. The intensity and the duration of the effect are dose related. Compared to that of morphine chlorhydrate, in the same conditions, the analgesia induced by fentanyl citrate is much less intense than expected: fentanyl seems to be only 25 times more potent than morphine. Furthermore, the observed duration of action of fentanyl makes it impossible to be still classified with the short time acting analgesics: with equianalgesic doses, morphine and fentanyl have the same time of initiation and the same duration of action. As observed, the time of the clinically useful analgesia is longer than 3 hours after injection of 0.006 mg/kg of fentanyl or of 0.150 mg/kg of morphine.
Fentanyl citrate or morphine chlorhydrate are injected intramuscularly at increasing doses to patients suffering from intense pain in the facial or trigeminal nerves territory: --fentanyl = 0.0015, 0.003, 0.006 mg/kg; --morphine = 0.100, 0.150, 0.200 mg/kg. The clinically observed side-effects are noted at regular time during the three hours following the injection. Fentanyl induces a drop in ventilation similar in duration to that of morphine, but it is more intense. Fentanyl induces less vomiting, but more euphoria than morphine and the sedation is the same in frequency and intensity with both drugs. The only difference of clinical importance concerns the cardio-vascular effects: morphine induces a constant, dose-related hypotension as that of fentanyl, at equianalgesic doses, is negligible.
Morphine chlorhydrate and buprenorphine chlorhydrate are given intramuscularly at increasing doses to patients suffering from intense pain in the facial or trigeminal nerves territory. No other drugs are used. The diverses groups of ten patients received respectively: --morphine: 0.100, 0.150, 0.200 mg/kg; --buprenorphine: 0.0015, 0.003, 0.006 mg/kg. On the whole, the analgesia is induced after a short time and is more durable, more intense as the dose is increased. Yet, concerning buprenorphine, the analgesia is not more intense with the 0.006 mg/kg dose, than with the 0.003 mg/kg dose. This phenomenon, if confirmed, would be an important limitation for the clinical use of this drug. For equianalgesic doses buprenorphine and morphine give an analgesia similar in time of initiation and in duration.
Side-effects of increasing doses of morphine (0.100, 0.150, 0.200 mg/kg) and buprenorphine (0.0015, 0.003, 0.006 mg/kg), given intramuscularly, are clinically observed in conscient subjects suffering from intense pain in the facial or trigeminal nerves territory. Buprenorphine induces a drop in ventilation even with the lower doses, which persists for 120-180 minutes. This effect is more important after the injection of an equianalgesic dose of morphine. The same phenomenon is observed for the drop in heart rate and for the hypotension, which remained in all cases very slight. The central side-effects are of the same nature with buprenorphine and with morphine. On the whole this phenomenon appears with the same frequency with both drugs, especially for drowsiness and sleep, for nausea, vomiting and dizziness. Yet, the patient under buprenorphine becomes more frequently confused and agitated. Lastly, a state of euphoria can occur which might be feared to be related to a drug-addict activity of buprenorphine.
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