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Biomedical subjects

L Lamy

Publications and source records attributed to L Lamy.

At least 19 recordsLinked to original sources
PubMed1991

The hemagglutinating adhesin HA-Ag2 of Bacteroides gingivalis is distinct from fimbrilin.

We carried out a series of immunoblots with antigenic preparations from the periodontal pathogen Bacteroides gingivalis using antisera of restricted specificity for the hemagglutinating adhesin HA-Ag2, and for the major structural subunit of the fimbriae (fimbrilin). We have been able to show that these 2 antigens are distinct. The fimbrilin subunit had an apparent molecular weight of 42 kDa in all of the bacterial preparations tested. HA-Ag2 occurred as a pair of bands at 43 and 49 kDa in outer membranes prepared as extracellular vesicles, and at 33 and 38 kDa in glass-bead-EDTA extracted antigens and in sheared-cell outer membranes prepared in the presence of EDTA. No HA-Ag2 was found in an enriched fimbrial preparation. The 2 antigens could thus be distinguished on the basis of their behaviour when subjected to different extraction techniques. The lower apparent molecular weight of HA-Ag2 (a pair of bands at 33 and 38 kDa) was invariably associated with the presence of EDTA in the buffers used to prepare the extracts, and the effect could be partially prevented by adding MgCl2 to the extraction buffer. The difference in apparent molecular weight of HA-Ag2 in the different extracts can thus be attributed either to an EDTA-sensitive tertiary conformation of its component polypeptides, or to an EDTA-sensitive linkage of each of these polypeptides to an unknown component of approximately 10 kDa.

Adhesins, Bacterial↗
PubMed1990

Modulation of egg-white lysozyme activity by viscosity intensifier additives.

The activity of egg-white lysozyme was measured in the presence of carbohydrate additives in the reaction medium. These additives show a significant affinity for water. They depress water activity and increase the viscosity of the medium. Solute-solvent interactions in aqueous solutions of the additives are characterized by properties such as the intrinsic viscosity, Huggins constant apparent molar volume and hydration number. It was found that, despite the lowering of enzyme activity when the concentration of additive is increased, the behavior remains Michaelian and neither modification of Km nor inhibition by excess substrate is observed. On the other hand, the effect of the viscosity of the medium on enzyme activity was determined. This effect is independent of the nature of the additive at high viscosities (greater than 4 mPa s-1) for which enzyme activity is very low and appears to vary according to the kind of additive in dilute solution at low viscosities (less than 2 mPa s-1).

Animals↗
PubMed1989

[Spiramycin].

Chemotherapeutic agents appear to offer a great potential in the treatment of periodontal disease in conjunction with root planning and/or surgical approach. One of these chemotherapeutic agents is spiramycin. The aim of this paper is to review some data about the spiramycin in vitro, in vivo, the effects of spiramycin on plaque control and some interesting hypothesis on action of spiramycin.

Dental Plaque↗
PubMed1988

Lysozyme kinetics in low water activity media. A possible hydration memory.

The influence of water activity on initial lysozyme kinetics is studied. Enzyme catalytic capacity exponentially increases with thermodynamical water activity of the reactant medium; this relation seems independent of the chemical structure of the water activity depressors but dependent on the structuration of water molecules they induce. This influence of water organization on initial enzyme activity is immediate and may be preserved even after a large dilution, thus lysozyme presents a "hydration memory" phenomenon. This effect is in accordance with sorption/desorption isotherms, an hysteresis loop being observed.

Culture Media↗
PubMed1987

Priorities in adolescent health care: the teenager's viewpoint.

The purpose of this study was to determine what issues teenagers want discussed or covered when they visit primary care physicians and to assess to what extent such discussion takes place. A questionnaire was administered to 1,564 students aged between 13 and 18 years in six high schools. Mean participant age was 15.3 years; 801 were male and 763 were female. Questions were drawn from both physical and psychosocial aspects of teenage life. The teenagers answered as to whether they would like to discuss the suggested topics on visits to physicians, and whether in fact such a discussion had taken place. The three topics of most interest to teenagers were physical fitness, nutrition, and growth. Teenagers wanted to discuss these topics in over 80 percent of the visits, and they indicated that actual discussion took place in just under 50 percent of the visits. Discussion of sexually transmitted disease was desired by teenagers 70 percent of the time, with a discussion rate of only 18 percent; contraception at 66 percent with a physician discussion rate of only 22 percent. If physicians discuss exercise, nutrition, and growth with teenage patients, in over 80 percent of cases they will be providing the patient with valued information. This initial dialogue will establish a base of communication that may allow for the discussion of issues teenagers often find more difficult (such as contraception, sexually transmitted disease, depression, drugs, and drinking).

Adolescent↗
PubMed1979

[Ectopic ureter ending in the seminal vesicle in adults. Apropos of a case and review of the literature].

The authors report a 38 years old patient in whom an intravenous pyelogram was performed for moderate arterial hypertension. This showed a large filling defect in the right lower part of the bladder without renal function on that side. Endoscopic separation of the jet coming from the right half of the trigone showed a liquid containing numerous spermatozoa. A cystogram opacified by reflux a cavity in the genital system via this, the right ureter. With the diagnosis of ectopic ureter ending in the genital system, a nephro-ureterectomy demonstrated the attachment of the ureter into a pouch which communicated with the bladder and the seminal vesicle. A view of the normal embryology insists on the fact that contrary to the classic view, the pronephros disappears entirely and that the metanephros is at the origin of the Woffian canal which opens on the posterior wall of the urogenital sinus at the 28th day when the ureter springs from a ureteral bud. Since 1960 this would be the 34th case in the literature, seminal ectopia (24%) coming after ectopia in the prostatic urethra (54%). Epididymitis is a frequent presenting symptom (44%). The workup shows: absence of renal function (100%), raising of the ipsilateral trigone by a cystic swelling (76%), absence of the meatus on that side on endoscopy, presence of an ipsilateral mass above the prostate on rectal examination (30%). The diagnosis is confirmed by vasography where the ureter is opacified by the seminal vesicle or by systography after endoscopic incision of the mass. Excision of the seminal vesicle was done in conjunction with total nephroureterectomy in 17% of cases.

Adult↗
PubMed1975

Inhibition of respiration and of respiratory development by different doses of chloramphenicol in frog embryos (Rana pipiens).

High doses of chloramphenicol (4.5 and 9 mM) directly inhibited respiration in conjunction with an unusual cleavage anomaly (blastomere refusion) in embryos of the frog, Rana pipiens. Lower doses (2.1-3 mM) did not affect respiration or cleavage and, when added later, did not directly affect respiration or development at any tested stage. Continuous incubation in the latter doses, however, did eventually, by day 6 or 7, produce a parallel retardation of embryonic development and of respiratory development relative to controls, suggestive of impaired mitochondrial biogenesis. A lower continuous dose (0.9 mM) affected neither respiration nor development at any stage.

Animals↗