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Biomedical subjects

C Lemasson

Publications and source records attributed to C Lemasson.

13 recordsLinked to original sources
PubMed1989

[Orthodontics of unilateral complete cleft lip-palate: point of view and personal proposals].

Studying 43 cases of unilateral cleft palate including 21 treated cases, the author notes that the lateral incisor is missing in 85% of the cases, the central near the cleft is badly rotated and there is a buccal cross bite in 45% associated or not with an anterior cross bite. He proposes to treat first the cross bite by fixed split palate appliance then to align the incisors at age 9. Then to wait until the patient is approximately 12 years old. At that moment a full fixed appliance is used; on the cleft side, the cuspid is usually placed against the central incisor and on the other side a bicuspid is usually extracted. Using this two steps therapy, the total treatment is no longer than 30 months.

Adolescent↗
PubMed1984

[Therapy of class II, division 1. Orthodontics or surgery?].

Concerning five observations of class II division 1, the authors justify therapies they used. Mandibular micrognathia is excluded. Proposed schedules are all based on a precise diagnosis and knowledge of abilities and limits of orthodontics. These limits depend upon orthodontical technics and also, individual factors, particularly if patient is an adult or a child. For a child, orthodontics are preferred and, according with prediction of mandibular growth and child's cooperation, non-extraction therapies are proposed. In adult, correction of deformity ignore such helpful factors as growth and cooperation; nevertheless, it can be successfully treated by orthodontics, using differential extractions, or, if orthodontics are impossible, by orthognathic surgery. Then, surgery will include orthodontical preparation and achievement of dental arches.

Adolescent↗
PubMed1976

Anomalies in the kinetics of photosynthetic oxygen emission in sequences of flashes revealed by matrix analysis. Effects of carbonyl cyanide m-chlorophenylhydrazone and variation in time parameters.

The model of Kok et al. (Kok, B., Forbush, B. and McGloin, M. (1970) Photochem. Photobiol. 11, 457-475) is considered the best kinetic explanation of the damped oscillations of O2 evolution induced in higher plants by a sequence of brief saturating flashes. Matrix analysis applied to this model shows that the parameters involved (distribution of S states at zero time, probabilities of transition between states induced by a flash) cannot be completely known from the O2 yield sequence, Yn. However, four quantities, with limited content of information, are readily derived from data, without additional assumptions. They are sigma1, sigma2 and sigma3, three quasisymmetrical functions of the transition coefficients, and Y, a weighed average of four consecutive Yn values. The extent of misses and double hits and their variations can be qualitatively ascertained by inspection of the relative values of sigma1, sigma2and sigma3. In a regular sequence (stricly obeying Kok's model), all four quantities should be constant along the time axis. It is shown that actual sequences are seldom regular, in particular in the following conditions: (1) variable flashing frequency, (2) addition of carbonylcyanide m-chlorophenylhydrazone, (3) incomplete deactivation, (4) change of flashing frequency at steady state. In order to account for these anomalies, it is proposed to modify Kok's model by introducing, in parallel to the four state storage entity (S states), a side carrier C, which can reversibly exchange a positive charge with it. In the new model, the transition coefficients are essentially time varying, thus producing a nonregular behaviour of Yn sequences.

Carbonyl Cyanide m-Chlorophenyl Hydrazone↗
PubMed1975

Photo-inactivation of system II centers by carbonyl cyanide m-chlorophenylhydrazone in Chlorella pyrenoidosa.

In the presence of a high concentration of carbonyl cyanide m-chlorophenylhydrazone (CCCP) (4-10(-6) M), the S2 and S3 dark decays are accelerated and become biphasic with a first half-time of 0.6 s. The first fast phase of the decays does not correspond to a simple reduction of S2, S3 back to S0, S1 (i.e. to an acceleration of the deactivation reaction), but to a decrease in the number of oxygen-evolving System II centers. This photo-inactivation produced by CCCP is rapidly reversible in the dark.

Carbonyl Cyanide m-Chlorophenyl Hydrazone↗
PubMed1973

Role of allophycocyanin as light-harvesting pigment in cyanobacteria.

Photosynthetic action spectra of several cyanobacteria show a peak at about 650 nm, the height of which is correlated with allophycocyanin content in the strains examined. Allophycocyanin harvests light more efficiently than do phycocyanin and phycoerythrin. The contribution of chlorophyll a absorption to photosynthetic activity is barely detectable in cells of normal pigment composition. Chlorophyll a becomes the major light-harvesting pigment in cells that have been physiologically depleted of phycobiliproteins.

Journal Article↗