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Biomedical subjects

M Leblanc

Publications and source records attributed to M Leblanc.

At least 91 records · Page 5Linked to original sources
PubMed1991

SOFI: a bidimensional detector for fast direct on-line quantification of beta particles on blots.

We present a high-speed, high-resolution beta imager developed to replace autoradiographic films currently used in molecular biology experiments. It allows the user to locate and make quantitative analyses of 32P-labeled molecules on a 25.6 x 25.6-cm flat surface. Combining new techniques--scintillating optical fibers and multianode photomultipliers--this fast imager offers several advantages when compared with recent gas detectors and flexibility for further improvements. Several biological applications will be discussed.

Animals↗
PubMed1988

[Prevalence of Aeromonas spp. pediatric gastroenteritis].

A selective medium and biochemical tests were used to search for Aeromonas spp. in the stools of 536 children, more than 90% of whom had "gastroenteritis", seen at Sainte-Justine Hospital, Montreal, in June or July 1986. The organism was found in seven children, six of whom had bloody diarrhea. One of the six, a 6 1/2-year-old boy, required intravenous alimentation and later manifested ulcerative colitis; the other five recovered. The remaining child, a 14-year-old boy, had synovitis of the knee and spondylarthritis. Two of the seven carried other enteric pathogens. The authors discuss the pathogenicity of Aeromonas spp., which is not very marked in temperate climates, in human summer diarrhea and its possible role in the development of ulcerative colitis.

Adolescent↗
PubMed1986

[Toward a second generation of fluorocarbon emulsions. Methodologies: synthesis of fluorocarbons, formulation, preparation and control of emulsions].

The fluorocarbons to be used as intravascular gas carriers may be prepared: by fluorination of hydrocarbons, by means of gaseous fluorine or of metallic fluorides or by electrolysis in anhydrous hydrogen fluoride; by selective synthesis from small fluorinated molecules. Selective synthesis seems preferable because of the high purity of the compounds thus obtained, allowing fairly simple purification and detoxification procedures. The adequacy of fluorocarbons for intravascular use (limited by the values of some of their crucial physicochemical properties such as vapour pressure, gas dissolving power, viscosity) was found dependent of their molecular weight range, preferably between 460 and 540 dalton. Ionic balance, osmolarity, viscosity, mean particle size and particle size distribution are among the most important criteria to be respected in the preparation of biocompatible emulsions. Several physicochemical methods were developed for selecting the best ingredients and the best emulsification procedures and for evaluating the stability of the emulsions to storage and to thermal stress. The combination of these physicochemical measurements may be used as a methodology for the optimisation and control of fluorocarbon emulsions as well as a way of evaluating new ingredients and formulations.

Biocompatible Materials↗
PubMed1984

[From juvenile delinquency to criminal adulthood.].

Where is the continuity between the conduct of delinquent adolescents and the antisocial behavior of young adults ? In examining a sample of conventional teenagers with a sample of young delinquents, the pattern of the delinquent behavior during adolescence is analyzed: its precocity, duration, aggravation, activity and diversity. It is there shown that the nature of the illicit activities during adolescence is directly predictive of the extent and nature of the adult criminal behavior.

English Abstract↗
PubMed1980

Analysis of visual evoked responses in multiple sclerosis.

In Multiple Sclerosis (MS) the modification of the latency of visual evoked responses (VER's) shows sequels of the involvement of anterior optic tracts manifested by a retro-bulbar optic neuritis (RBON). This study was made on 102 patients with MS. The stimulus used the pattern reversal of a checkboard. The influence of the size and squares 8' and 20' chosen as stimulus has been first studied in patients with antecedents of RBON. Using the 8' squares, all eyes with a history of RBON had pathological VER's. When there is no clinical antecedent of RBON, this means of stimulation enabled us to detect sequels of RBON. In "definitive" and "probable" MS, 100% of patients had pathological VER's either for both eyes of a single eyes. In "possible" MS a sequel of RBON was demonstrated in 57% of this population without clinical antecedent of RBON. A correlation between VER's result and the ophthalmological examination (visual acuity, fundoscopic examination and acquired dyschromatopsie) was made. Although VER's are an excellent method for detecting the sequels of RBON in MS. VER's abnormalities have no etiological significance, they are observed in other neurological involvements of anterior optic tracts. These different points are discussed and a physiological interpretation of VER's abnormalities is proposed.

Color Perception↗
PubMed1979

[Study of colour vision and visual evoked responses in multisclerosis diagnosis (author's transl)].

In a patient with suspected Multisclerosis (M.S.), the discovery of a lesion in the anterior optic tracks is of considerable diagnostic importance. If none of the classical clinical signs of optic neuritis can be found, the study of visual evoked responses (VER) and of colour vision is useful evidence for diagnosis. In a population of 102 patients having "possible", "probable" or "confirmed" M.S, we have compared the information provided by both these methods. 27 patients had MS with a known optic neuritis: the VER and colour vision of all of them was altered, either unilaterally or bilaterally. 75 patients had "possible" or "probable" MS without a history of optic neuritis. For 34,7%, the discovery of a dyschromatopsia showed a lesion in the optic nerve. In 68%, only the increased latency in VER demonstrated an optic neuritis. It should be noted that for all the patients with "probable" or "confirmed" MS, the VER latency was increased. The study of colour vision is therefore in our opinion, an excellent way of investigating anterior optic tracks lesions. When the study of colour vision is not sufficient, the recording of VER is a reliable technique and a very valuable acquisition in neuro-ophthalmology.

Adult↗
PubMed1977

[Recording of visual evoked potentials in the diagnosis of multiple sclerosis].

The authors report the results of recording EVP obtained by pattern reversal in 20 controls and 43 patients with "established", "probable" or "possible" MS on the basis of MacAlpine's criteria. Whilst the latency of the wave 1 of the EVP appeared stable in the controls (107.5 msec +/- 7.46), lengthening of the latency of the EVP was seen in 77p. 100 of cases, confirming involvement of the visual pathways, though bulbar neuritis had been known clinically in only 28 p. 100 of patients. The value of this method of recording EVP in contributing to the diagnosis of DS is discussed.

Adolescent↗
PubMed1976

[Polyradiculoneuritis in a diabetic patient. Ultrastructural study of a biopsy of a peripheral nerve].

We have made a study of a case of polyradiculoneuritis occurring in a diabetic. Clinically, symptoms were very similar to those in classical Guillain-Barré syndrome and respiratory complications necessitated a stay in a Respiratory Resuscitation Centre. Recuperation was slow but practically total. Ultrastructural changes noted in the roots and the peripheral nerves of patients suffering from Guillain-Barré syndrome are similar to those occurring in experimental allergic neuropathies. These changes are specific as the myelin takes on a fishnet appearance and, more important, the myelin is attacked by the projection of a mononucleate cell which has passed through the cytoplasm of the Schwann cells. We did not find this in our case. On the other hand, the lesions we found consisted of a mixture of common segmental demyelinization and axonal lesions, associated with marked Schwann cell hypertrophy coiled around most of the myelinized fibres. Such aspects are very like those found in certain diabetic neuropathies. The existence of significant microangiopathy which was present in this case is also an important, though not a decisive factor. We consider, therefore, that the syndrome of polyradiculoneuritis exhibited by this patient corresponds more closely to diabetic neuropathy than to a classical Guillain-Barré syndrome.

Adolescent↗
PubMed1975

[Polyneuritis in chronic lymphoid leukemia. Ultrastructural study of the peripheral nerve (author's transl)].

A 75 years old man had a chronic lymphoid leukemia for 5 years. Within a period of three months he developed a polyneuritis. The biopsy of a peripheral nerve showed a large cellular infiltration by lymphocytes. The ultrastructural study shows in some Schwann cells disruption of the myelin. Their cytoplasm is invaded by a lymphocyte process as in Guillain-Barré. But in this case some of these invading lymphocytes show polygonal structures in their cytoplasm; that is sometimes seen in the proliferating cells of the chronic lymphoid leukemia.

Aged↗