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Biomedical subjects

J Richard

Publications and source records attributed to J Richard.

At least 37 records · Page 2Linked to original sources
PubMed1999

Naked DNA vaccination of Atlantic salmon Salmo salar against IHNV.

A naked plasmid DNA encoding the glycoprotein (pCMV4-G) of a 1976 isolate of infectious hematopoietic necrosis virus (IHNV) obtained from steelhead Oncorhynchus mykiss was used to vaccinate Atlantic salmon Salmo salar against IHNV. Eight weeks post-vaccination the fish were challenged with a strain of IHNV originally isolated from farmed Atlantic salmon undergoing an epizootic. Fish injected with the glycoprotein-encoding plasmid were significantly (p < 0.05) protected against IHNV by both immersion and cohabitation challenge. Survivors of the first challenges were pooled and re-challenged by immersion 12 wk after the initial challenge. Significant (p < 0.05) protection was observed in all of the previously challenged groups including those receiving the complete vaccine. Fish injected with the glycoprotein-encoding plasmid produced low levels of virus-neutralizing antibodies prior to the first challenge. Neutralizing antibodies increased in all groups after exposure to the IHNV. Passive transfer of pooled sera from pCMV4-G vaccinates and IHN survivors provided relative survivals of 40 to 100% compared to fish injected with sera collected from fish immunized with control vaccines or left unhandled. In this study, DNA vaccination effectively protected Atlantic salmon smolts against challenges with IHNV.

Animals↗
PubMed1998

Differences in visual search tasks between congenitally deaf and normally hearing adults.

In order to study the processes of central vision in deaf subjects, 12 congenitally deaf adults and 12 normally hearing adults performed a visual search task. The task consisted of detecting a "Q" target among "O" distractors in variable numbers and the reverse. The method used a paradigm based on the stimulus onset asynchrony (SOA) specifically designed to measure the visual processing time between the visual array and a mask. A different visual search pattern was observed in each group. The hearing subjects showed an asymmetrical visual search pattern (parallel versus serial processing respectively for "Q" and "O" targets). In contrast, the deaf subjects showed a symmetrical search pattern (parallel processing in both experimental conditions). In a visual task selectively supported by central vision, visual processes of the congenitally deaf are more efficient when the task involves the contribution of serial processes.

Adolescent↗
PubMed1998

A comparison of skin storage methods for oculoplastic surgery.

PURPOSE: To assess the level of contamination of full-thickness skin grafts stored with or without an antibiotic cover. METHODS: Full-thickness skin grafts were harvested from 40 bilateral upper lid blepharoplasties. Before surgery the face was sterilised, the head of the patient was packed with sterile, single-use surgical drapes and the whole face was left exposed. The harvested full-thickness skin grafts were conserved in sterile containers at 4 degrees C for 6 days, rolled in gauze moistened with either 4 ml of sterile saline solution (group I) or with 4 ml of gentamicin solution (2 mg/ml) (group II). The degree of contamination, expressed in colony forming units (CFU), was evaluated on days 2, 3, 4, 5 and 6. Identification of the microorganisms was done to species level following standard procedures and commercial methods. RESULTS: In group I 2 grafts (5%) were negative during the whole observation period while the other 38 grafts (95%) presented a degree of contamination ranging from 10(2) to 10(4) CFU. Microorganisms isolated were: Staphylococcus epidermidis (24 cases), Staphylococcus aureus (5 cases), Staphylococcus saprophyticus (2 cases), Pseudomonas aeruginosa (4 cases), Serratia liquefaciens (1 case) and Klebsiella oxytoca (2 cases). In group II, 26 grafts (65%) were negative during the whole observation time while in 14 cases (35%) a few colonies (3 to 6) of Candida albicans were isolated on day 2 and remained constant in number for the whole observation time. CONCLUSIONS: The storage of full-thickness skin graft with an antibiotic cover is more reliable than the storage of full-thickness skin graft without an antibiotic cover.

Anti-Bacterial Agents↗
PubMed1998

Functional coupling and regional activation of human cortical motor areas during simple, internally paced and externally paced finger movements.

We studied the activation and interaction of cortical motor regions during simple, internally paced and externally paced right-hand finger extensions in healthy volunteers. We recorded EEGs from 28 scalp electrodes and analysed task-related coherence, task-related power and movement-related cortical potentials. Task-related coherence reflects inter-regional functional coupling of oscillatory neuronal activity, task-related power reflects regional oscillatory activity of neuronal assemblies and movement-related cortical potentials reflect summated potentials of apical dendrites of pyramidal cells. A combination of these three analytical techniques allows comprehensive evaluation of different aspects of information processing in neuronal assemblies. For both externally and internally paced finger extensions, movement-related regional activation was predominant over the contralateral premotor and primary sensorimotor cortex, and functional coupling occurred between the primary sensorimotor cortex of both hemispheres and between the primary sensorimotor cortex and the mesial premotor areas, probably including the supplementary motor area. The main difference between the different types of movement pacing was enhanced functional coupling of central motor areas during internally paced finger extensions, particularly inter-hemispherically between the left and right primary sensorimotor cortexes and between the contralateral primary sensorimotor cortex and the mesial premotor areas. Internally paced finger extensions were also associated with additional regional (premovement) activation over the mesial premotor areas. The maximal task-related coherence differences between internally and externally paced finger extensions occurred in the frequency range of 20-22 Hz rather than in the range of maximal task-related power differences (9-11 Hz). This suggests that important aspects of information processing in the human motor system could be based on network-like oscillatory cortical activity and might be modulated on at least two levels, which to some extent can operate independently from each other: (i) regional activation (task-related power) and (ii) inter-regional functional coupling. We propose that internal pacing of movement poses higher demands on the motor system than external pacing, and that the motor system responds not only by increasing regional activation of the mesial premotor system, including the supplementary motor area, but also by enhancing information flow between lateral and mesial premotor and sensorimotor areas of both hemispheres, even if the movements are simple and unimanual.

Adult↗
PubMed1998

The contribution of caseins to the amino acid supply for Lactococcus lactis depends on the type of cell envelope proteinase.

The ability of caseins to fulfill the amino acid requirements of Lactococcus lactis for growth was studied as a function of the type of cell envelope proteinase (PI versus PIII type). Two genetically engineered strains of L. lactis that differed only in the type of proteinase were grown in chemically defined media containing alphas1-, beta-, and kappa-caseins (alone or in combination) as the sources of amino acids. Casein utilization resulted in limitation of the growth rate, and the extent of this limitation depended on the type of casein and proteinase. Adding different mixtures of essential amino acids to the growth medium made it possible to identify the nature of the limitation. This procedure also made it possible to identify the amino acid deficiency which was growth rate limiting for L. lactis in milk (S. Helinck, J. Richard, and V. Juillard, Appl. Environ. Microbiol. 63:2124-2130, 1997) as a function of the type of proteinase. Our results were compared with results from previous in vitro experiments in which casein degradation by purified proteinases was examined. The results were in agreement only in the case of the PI-type proteinase. Therefore, our results bring into question the validity of the in vitro approach to identification of casein-derived peptides released by a PIII-type proteinase.

Amino Acid Sequence↗
PubMed1998

[Extra-coronary atherosclerosis in documented coronary patients].

The prevalence and severity of extracoronary atherosclerosis in 728 patients (572 men and 156 women; average age 59 years) referred for coronary angiography and who had a history of coronary disease for at least 2 years, were assessed by ultrasonography. This population was divided into 3 groups: Group I, 115 patients without lesions at coronary angiography: Group II, 76 patients with mild coronary stenosis ang Group III, 537 patients with at least one severe coronary artery stenosis, a group which included 294 cases of single vessel disease. The authors observed a strong correlation between the presence, severity and diffusion of the coronary artery disease and ultra sonographic signs of peripheral arterial disease: the frequency increased regularly from 45% in Group I to 88% in patients with triple vessel disease in Group III. About two thirds of patients in Group III had carotid or lower limb atherosclerosis and half of them had atherosclerosis or aneurysm of the abdominal aorta. Severe peripheral lesions were not common but all the aortic aneurysms were observed in Group III. Similarly, simultaneous disease in all three peripheral arterial territories ranged from 12% in Group I to 51% in Group III. The risk of finding peripheral arterial disease was increased in patients with coronary artery disease compared with normal subjects. For each peripheral localisation, the risk was two-fold in cases of mild coronary disease and three or four-fold in patients with triple vessel disease in whom the risk of finding at least one severe peripheral lesion was multiplied by ten. The authors conclude that the prevalence and severity of ultrasonographic peripheral atherosclerosis in documented coronary patients was closely related to the presence, severity and diffusion of the coronary lesions.

Adult↗
PubMed1997

Antilisterial activity of three bacteriocins used at sub minimal inhibitory concentrations and cross-resistance of the survivors.

The kinetics of inhibition of Listeria innocua strain Lin11 in a nutrient broth containing either nisin, pediocin AcH, or enterococcin EFS2 at concentrations ensuring a 2-3 log reduction of the population were first investigated. The rate of inhibition differed considerably between the bacteriocins. At the time that maximum viability loss occurred in the cultures containing either nisin (12 AU ml(-1)) or pediocin AcH (50 AU ml(-1)) the survivors resumed growth, although the medium retained most of its initial inhibitory activity. The survivors displayed increased resistance not only toward the bacteriocin they were in contact with, but toward the two other bacteriocins under study.

Bacteriocins↗
PubMed1997

A case-control analysis of risk factors in HIV transmission in South India.

A case-control study was done among patients attending our clinic for sexually transmitted diseases in South India to assess risk factors for human immunodeficiency virus (HIV) infection. Of 5,876 patients tested, 105 (1.79%) were HIV antibody positive (87 men, 18 women) by enzyme-linked immunosorbent assay and Western blot. They were compared with an equal number of age- and sex-matched patients without HIV antibody. Risk factors significant in the crude odds ratio analysis were occupation (truck drivers and truck cleaners), age at first exposure, and sexual contact with commercial sex workers. In the logistic regression analysis, only a history of past genital ulcer was a significant risk factor. Other important findings of this study were that (a) the spread of HIV to women is mostly from their infected husbands and (b) regular condom use was reported by less than 8% of patients and controls. Obviously, the current methods of education of the population are far from adequate.

Adult↗
PubMed1997

Primary care physicians and coronary heart disease prevention: a practice model.

Primary care physicians have an important role in coronary heart disease prevention. This paper discusses the results of a qualitative study conducted with Nova Scotian physicians to explore the following: physicians' expectations about their role in prevention; obstacles to providing preventive care; and, mechanisms by which preventive care occurs. The second part of the paper presents a practice model which is intended as a framework by which physicians may more effectively educate and counsel their patients about health issues, such as coronary heart disease.

Coronary Disease↗
PubMed1997

Development of a Chemically Defined Medium for the Growth of Leuconostoc mesenteroides.

A chemically defined medium for the growth of Leuconostoc mesenteroides was developed. This medium contained lactose, Mn(sup2+), Mg(sup2+), 12 amino acids, eight vitamins, adenine, uracil, and Tween 80. We showed the beneficial effect of aerobic conditions on growth and that potassium phosphate (135 mM) is a suitable buffer. The growth rate in this medium was 0.85 (plusmn) 0.10 h(sup-1) for the six strains examined, and cell densities up to 3.5 x 10(sup9) CFU/ml were attained.

Journal Article↗
PubMed1997

The effects of adding lactococcal proteinase on the growth rate of Lactococcus lactis in milk depend on the type of enzyme.

Increasing the proteolytic activity of Lactococcus lactis cultures in milk by adding the corresponding proteinase resulted in a stimulation of the growth rate regardless of the strain and the type of proteinase, demonstrating that the rate of casein degradation was responsible for the growth rate limitation of L. lactis in milk. However, the stimulation was only transient, and the reduction in growth rate in the poststimulation phase depended on the type of cell envelope proteinase. When a PI-type proteinase was added, three causes were involved in the subsequent reduction in growth rate: degradation of the added proteinase, repression of the proteolytic activity expressed by the cells, and competition for peptide uptake. When a PIII-type proteinase was added, the cessation of stimulation was due to the autoproteolysis of the added enzyme only.

Animals↗
PubMed1997

Interaction between proteolytic strains of Lactococcus lactis influenced by different types of proteinase during growth in milk.

The influence of the type of cell envelope-located proteinase (PI versus PIII) on the associative growth of Lactococcus lactis in milk was studied. Two genetically engineered strains, differing only by the type of proteinase, were first used as a model study. An interaction occurred during the second exponential growth phase of the mixed culture and resulted in a decrease in growth rate of the PI-type proteinase strain, whereas that of the PIII-type proteinase strain remained unaffected. The reduction in proteolytic activity of the PI-type proteinase strain (presumably resulting from an inhibition of the synthesis of the enzyme) due to the peptides released by the PIII-type proteinase was found to be partly responsible for this interaction. Extension of the study to wild-type proteinase-positive L. lactis strains showed a systematic imbalance of the mixture of the two strains in favor of the PIII-type proteinase strain.

Animals↗
PubMed1997

[Motor performance in Alzheimer's disease].

Movement and motor expression are indirect means of approaching the affectivity of patients suffering from Alzheimer's disease. This is why it is very important to describe here two therapeutical approaches: a) on the one hand, an approach which focuses on the physical and psychical functioning of the patient: b) on the other hand, an approach which validates a new type of therapy, psychomotor therapy.

Activities of Daily Living↗
PubMed1996

Cell wall changes in nisin-resistant variants of Listeria innocua grown in the presence of high nisin concentrations.

Two nisin-resistant variants of a strain of Listeria innocua were isolated after growth in the presence of 500 and 4000 IU ml-1 of nisin A showed increased cell wall hydrophobicity, resistance to phage attack and three different cell wall-acting antibiotics, as well as to the peptidoglycan hydrolytic enzymes lysozyme and mutanolysin, as compared to the parental strain. Transmission electron microscopy revealed marked thickening of the wall of nisin-resistant cells with an irregular surface. Differences in thickness were lost after cell wall purification and no significant difference in gross wall composition was observed between the parental and resistant variants. Cell wall changes in nisin-resistant listeriae are attributed to abnormal cell wall synthesis and autolysin inhibition, the latter possibly associated with subtle changes in cell wall structures and function.

Anti-Bacterial Agents↗
PubMed1996

Purification, partial characterisation and mode of action of enterococcin EFS2, an antilisterial bacteriocin produced by a strain of Enterococcus faecalis isolated from a cheese.

Enterococcus faecalis strain EFS2, isolated from the surface of a traditional cheese, produced a bacteriocin active against Gram-positive bacteria including Listeria spp. and some Staphylococcus aureus strains. The bacteriocin, named enterococcin EFS2, has been purified to homogeneity by ammonium sulphate precipitation and reversed-phase high performance liquid chromatography (RP-HPLC). The molecular weight was determined by mass spectrometry to be 7149.6. The amino acid composition of enterococcin EFS2 revealed that it contained 67 amino acid residues and had a blocked amino-terminal end. Enterococcin EFS2 induced viability loss, efflux of K+ ions and ATP, and cell lysis. Kinetic study of bactericidal activity of enterococcin EFS2 on Listeria innocua strain LIN11 indicated slower cell destruction than by nisin. At pH 7.0, the activity of enterococcin EFS2 was the highest at 35 degrees C and was lost at 15 degrees C. The bacteriocin was more active against L. innocua strain LIN11 in broth adjusted to pH 6.0, 7.0 and 8.0 than to pH 4.5 at 30 degrees C.

Amino Acids↗
PubMed1996

Trends in intra-uterine growth of single live births in southern India.

Trends in intra-uterine growth (IUG) of newborns from 1969-1973 to 1989-1993 were studied among rural and urban communities. Yerushalmy's five group classification of IUG was used. The percent preterm low birthweight (LBW) declined from 7 to 3 in rural and from 5 to 2 in urban areas. The percent of newborns with retardation of IUG declined from 20 to 11 in rural and from 13 to 8 in urban areas. Possible factors contributing to such changes are discussed.

Birth Weight↗