Biomedical subjects
Publications and source records attributed to L Gauthier.
Varicella disciform stromal keratitis is rare. It occurs several weeks or months after the skin rash. We report 4 cases in children, two of whom developed one or more recurrent episodes. Treatment based on local steroids was long and difficult to dose. One case treated with oral aciclovir did not show a better clinical course than the other patients.
There seems to be a consensus today by which a child, who is a victim of incest or sexually abused, must be directed to therapy in order that he or she provides a factual account of the traumatism and, by the same token, exorcises it. The authors deplore the widespread use of this destabilizing method. They emphasize that, for many children, recovery is achieved more successfully through "repression" (in the psychoanalytical sense of the term). After having obtained disclosure from the child, the authors argue that it is preferable for the intervenor to create the appropriate therapeutic conditions allowing the child to positively bury the event and move on with his or her life.
The protein, HPr, a necessary component of the phosphoenolpyruvate phosphotransferase system (PTS) in bacteria, was purified from Streptococcus salivarius by column chromatography. The purified preparation gave only one band when analyzed by sodium dodecylsulfate gel electrophoresis or by isoelectric focusing in polyacrylamide gel (pI = 4.85). However, electrophoresis in Tris-containing buffers under non-denaturing conditions revealed 2 bands that could be phosphorylated by PEP in the presence of enzyme I of the PTS or by ATP with the HPr kinase. Homogeneous preparations of these 2 forms could be obtained by preparative electrophoresis. Each preparation exhibited only 1 band when analyzed by electrophoresis under non-denaturing conditions, indicating that the doublet observed before preparative electrophoresis was not an electrophoretic artefact. The electrophoretic mobility of each protein was not modified following heat-treatment at 100 degrees C for 20 min or storage at -40 degrees C for several months. Both HPr proteins catalyzed in vitro the PEP-dependent phosphorylation of glucose, but at a rate slightly lower than that observed with a preparation of HPr containing both forms of the protein. Both forms were also able to transfer the phosphate group from PEP to the other specific PTS proteins known in S salivarius. Rabbit polyclonal antibodies directed against each form reacted with both proteins. The presence of the 2 forms of HPr was detected in fresh cellular extracts of S salivarius; however, their intracellular ratio varied according to growth conditions. A doublet was also found in many other streptococcal species tested (S mutans, S sobrinus, S sanguis, S thermophilus, S bovis, S rattus) and also in L lactis.(ABSTRACT TRUNCATED AT 250 WORDS)
HPr is a small phosphocarrier protein of the bacterial phosphoenolpyruvate:sugar phosphotransferase system involved in the transport and phosphorylation of sugars. It has recently been reported that streptococci possess two forms of HPr having identical biochemical properties. In this communication, we show by N-terminal amino-acid sequencing and by ion-spray mass spectroscopy that these two forms differ by the presence or the absence of the N-terminal methionine.
The relative failure of symptomatic therapeutic trials for Alzheimer's disease using non-selective cholinergic agonists brings about the need for longitudinal studies with parallel designs aimed at disease stabilization, using trophic substances or amyloid suppressors.
Although spatial disorientation is frequently observed in persons with Alzheimer disease, it is not well understood. A descriptive study was conducted to examine spatial skills associated with spatial orientation. Spatial tasks were selected and grouped into three types of spatial skills: perceptual, cognitive, and functional. These spatial tasks were administered to a group of 15 persons with senile dementia of the Alzheimer type (SDAT) (early Alzheimer disease) and a group of 15 control subjects. The results indicated that the subjects with SDAT were impaired on half of the perceptual spatial tasks and all of the cognitive spatial tasks. On the functional spatial tasks, however, the subjects with SDAT showed impaired skills in the new environment but intact skills in familiar environments. Spatial disorientation poses a danger and limits a person's ability to independently perform daily activities that require navigation outside of the home. Occupational therapy should therefore include the assessment of spatial orientation skills in persons who are in the early stages of dementia.
We show in this article that the transport of glucose, mannose and fructose by the phosphoenolpyruvate: mannose phosphotransferase system of oral streptococci requires the participation of a protein component that we have called IIIman. This protein was purified from Streptococcus salivarius by chromatography on DEAE-cellulose, DEAE-TSK, hydroxyapatite, and Dyematrex Green A. The purified protein migrated as a 38,900 molecular weight protein on a sodium dodecyl sulfate polyacrylamide gel. However, electrophoretic analysis of phosphoproteins and Western blot experiments indicated the presence in membrane-free cellular extracts of S. salivarius of 2 different forms of IIIman having molecular weights of 38,900 and 35,200. The presence of the high-molecular-weight form of IIIman was observed by immunodiffusion, Western blot and phosphorylation by [32]PEP in S. salivarius, Streptococcus mutans, Streptococcus sobrinus, and Streptococcus lactis but not in Streptococcus faecium, Staphylococcus aureus, Bacillus subtilis and Lactobacillus casei. Antibodies directed against the IIIman of S. salivarius did not react with the IIIman of Escherichia coli.
The physiological and biochemical characterization of Streptococcus salivarius mutants isolated by positive selection for resistance to 0.5 mM 2-deoxyglucose in the presence of lactose are reported. We found 2 classes of mutants following a series of experiments that included: growth rate determinations, uptake studies, measurement of phosphotransferase system (PTS) activities and detection of the IIIman proteins by Western blotting and analysis of [32P]PEP-phosphorylated proteins. Class 1 mutants did not possess the low-molecular-weight form of IIIman. They did not grow on mannose and were unable to transport 2-deoxyglucose. On the other hand, class 2 mutants possessed the 2 forms of IIIman, grew readily on mannose and transported 2-deoxyglucose, albeit at a lower rate than the parental strain. Both classes of mutants exhibited abnormal growth in media containing mixtures of sugars. Moreover, derepression of genes coding for catabolic enzymes was observed in all the mutant strains. Our data suggested that the role of the mannose PTS in the control of sugar utilization in S. salivarius is complex and may involve the participation of several components.
Functional difficulties occur in all patients with Alzheimer's disease. Instrumental skills (shopping, handling money) are involved first, then self-care activities (toileting, dressing). Drug trials in intermediate stage Alzheimer's disease should monitor self-care activities with structured diaries and rating scales.
The conjunctival and corneal lesions usually observed in the floppy eyelid syndrome are benign and reversible as soon as the specific treatment of superior palpebral hyperlaxity is performed. A case of bilateral corneal vascularization, a rare but severe complication of floppy eyelid syndrome is reported. The floppy eyelid syndrome was identified late because keratoconjunctivitis was clinically predominant and palpebral tonicity was not initially considered. The treatment of palpebral hyperlaxity was the prerequisite for good results with keratoplasty.
The micronucleus test using erythrocytes of Pleurodeles waltl larvae (Amphibian, Salamandridae) was used to detect the genotoxic activity of various substances. Most of them were known (or suspected) to be mutagenic or carcinogenic in mammals. Larvae were reared in water containing either a test chemical (experimental group) or in control water and the levels of micronucleated red blood cells (RBCs) compared between the two groups. Aroclor 1254, butylated hydroxyanisole, phenobarbital and 12-O-tetradecanoyl-phorbol-13-acetate produced negative results, while acridine orange, benzo[alpha]pyrene, epsilon-caprolactam, cyclophosphamide, diethyl sulphate, epichlorhydrin, ethidium bromide, ethyl methanesulphonate, ethylene dibromide (dibromoethane), N-ethyl-N'-nitro-N-nitrosoguanidine, N-ethyl-N-nitrosourea, hexamethylphosphoramide, 3-methyl cholanthrene, pyrene and o-toluidine gave positive responses. The results were compared with published data from other tests used to detect the clastogenic or mutagenic properties of chemicals. We suggest that the newt micronucleus test could be used to monitor aquatic pollution, and/or for the quality control of drinking water. Pleurodele larvae may also prove to be of value for the detection of carcinogenic/clastogenic substances dissolved in water.
We have previously described a micronucleus test using erythrocytes from larvae of the urodele amphibian Pleurodeles waltl (pleurodele). The test is based on a comparison of the levels of micronucleated erythrocytes in blood smears from larvae reared in water containing a clastogen, with the levels from larvae reared in purified water. We have employed this test to evaluate mutagenic activity of chlorinated or monochloraminated water devoid of all organic matter. (i) The level of micronuclei in erythrocytes was compared between a group of larvae reared for 12 days in chlorinated reconstituted ultrapure water treated with sodium hypochlorite, and a control group reared in just the reconstituted water. Sodium hypochlorite was added when both the food and medium were changed each day. Chlorine levels of 0.125 and 0.25 p.p.m. led to significant elevations of micronuclei. (ii) The possibility of indirect effects of chlorine through chemical interactions with the food were also investigated, using the following scheme: larvae were left for 3 h in chlorinated reconstituted ultrapure water and then placed in non-chlorinated water. Food was only introduced when they were transferred to the non-chlorinated water. This procedure was repeated for 12 consecutive days. Control larvae were reared in non-chlorinated water throughout this period. In this case results were also positive when the larvae were exposed for only 3 h to the chlorine (0.2 p.p.m. for 12 days) in the absence of food. (iii) This was the same as experiment 1 except that the water was chlorinated with monochloramine instead of sodium hypochlorite.(ABSTRACT TRUNCATED AT 250 WORDS)
Growth of Streptococcus mutans Ingbritt in continuous culture (pH 7.0, dilution rate of 0.1 h-1) at medium glucose concentrations above 2.6 mM resulted in repression of the sugar-specific membrane components, enzyme IIGlc (EIIGlc) and EIIMan, of the phosphoenolpyruvate:sugar phosphotransferase system (PTS). In one experiment, significant repression (27-fold) was observed with 73 mM glucose when the glycolytic capacity of the cells was reduced by only 2-fold and when the culture was still glucose limited. In a more comprehensive experiment in which cells were grown in continuous culture at eight glucose concentrations from 2.6 to 304 mM, in addition to repression of specific EII activities for glucose, mannose, 2-deoxyglucose, and fructose, synthesis of the general protein, EI, was repressed at all glucose levels above 2.6 mM to a maximum of 4-fold at 304 mM glucose when the culture was growing with excess glucose (i.e., nitrogen limited). The other PTS general protein, HPr, was less sensitive to the exogenous glucose level but was nevertheless repressed fourfold under glucose-excess conditions. The Km for glucose for EIIGlc increased from 0.22 mM during growth at 3.6 mM glucose (glucose limited) to 0.48 mM at 271 mM glucose (glucose excess). The shift from heterofermentation to homofermentation during growth with increasing glucose levels suggests the involvement of glycolytic intermediates, ATP, or another high-energy phosphate metabolite in regulation of the synthesis of the PTS components in S. mutans.
Fibrin sealant is used to close perforated or preperforated corneal ulcers. In addition to the usual advantages of cyanoacrylates it is degraded physiologically and provides a good support for corneal healing. Corneal grafting can be avoided when contraindicated or postponed when conditions allow. This technique has been successful in nine eyes of eight patients.
Several lines of evidence have implicated acetylcholine (ACh) as one of the neurotransmitters found to be decreased in Alzheimer's disease (AD). Various methods of cholinergic augmentation have been attempted, with mixed results. Tetrahydroaminoacridine (THA), an acetylcholinesterase inhibitor, is currently being investigated at the McGill Centre for Studies in Aging. Preliminary uncontrolled data from a 10-week clinical trial of THA and lecithin, reported elsewhere, suggest a clinically modest but statistically significant beneficial effect on cognition, although problems exist with side effects, particularly gastrointestinal. Since the suggestion by Janowsky in 1972 that cholinergic neurotransmission may exert an inhibitory or depressant effect on mood, the evidence accumulated in the literature has been inconclusive. We undertook to assess several potential pretreatment correlates of depressive symptoms in AD and to monitor the course of these symptoms during the 10 week treatment period, using the Geriatric Depression Scale (GDS) of Brink and Yesavage. Pretreatment GDS scores were found to correlate with degree of overall disability and dementia as measured by the Rapid Disability Rating Scale (RDRS) and the Mini Mental State Examination (MMS), respectively. GDS scores over the treatment period did not change to a statistically significant degree. The meaning of these results is discussed, particularly with reference to the difficulty of diagnosis and measurement of depression in the setting of dementia.
Ten years ago, we surmised that VKC could be provoked by chlamydia. 34 patients without any contamination of trachomatous origin were recently studied. We performed examinations of biopsies (histology and ultrastructure), serology, tissue group and specific allergen skin tests. Our findings indicate that Chlamydia could be an allergen provoking VKC in atopic patients.
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