Comptes rendus des seances de l'Academie des sciences. Serie D, Sciences naturelles最新文献

Pyrophosphorolysis, the reverse reaction of nucleotide polymerisation during replication or transcription must influence error-rates. Calculations suggest, for a wide range of reaction mechanisms, a linear dependency between pyrophosphate concentration and the ratio correct/incorrect substrate incorporation. Errors in A.T -rich regions should be particularly sensitive to changes in pyrophosphate concentration.

Some characteristics of the horizontal optokinetic nystagmus (OKN) have been studied in the pigeon using monocular and binocular stimulations. The OKN is asymmetrical, temporal to nasal stimulation eliciting a larger response than a nasal to temporal one. The role of the accessory optic system (AOS) was studied by means of unilateral or bilateral lesions of the primary relays, nuclei ectomamillaris (nEM) and superficialis synencephali (nSS). Results show the existence of a synergy between nEM and nSS on the same side and between nEM and nSS on opposite sides, whereas each nucleus has an inhibitory effect upon its contralateral homologue. Some evidence was obtained which suggests the existence of an ipsilateral retinal projection to the nEM.

The effects of tremogenic doses of harmaline have been studied by extracellular unit recordings and 14C 2-deoxyglucose marking in two groups of cats. Harmaline sensitive neurons were found in the lateral reticular nucleus and the nucleus reticularis tegmenti pontis. The nucleus interpositus as well as the red nucleus were also found to be discharging at the tremor frequency, indicating that the cerebello-interposito-rubral system participates in harmaline tremor. In cats with unilateral sections of the inferior cerebellar peduncle, 14C 2-deoxyglucose marking demonstrated that the increased activity previously observed in those structures was a consequence of harmaline acting on the inferior olive.

A cellular hybrid secreting a Mouse monoclonal immunoglobulin (IgG) specific of human leukocyte interferon has been obtained, following fusion of a nonsecreting variant of the myeloma P3X63 Ag8 with splenic lymphocytes from a Mouse immunized against interferon incorporated into liposomes. The antibody also recognizes human interferon made by a bacterial recombinant and a fraction of interferon made by Namalva cells. Mass production of the antibody has been achieved using ascitic growth of the hybrid in Mice.

When administered intravenously to Rats, 14C Gentamicin decreased very fast in all tissues, except in kidney and cartilage. Some flexures of the small intestine contained radioactive carbon, and that was evidence for the biliary elimination of a part of the aminoglycoside. In animals with water restriction, the distribution of the antibiotic in tissues was similar to the distribution in animals with free access to water.

GTG chromosomic banding of a male and a female Lophocebus albigena is reported. The chromosome number of the karyotypes is 2 n = 42, characterized by a pair of marked chromosomes and a mediocentric Y chromosome, similar to that of the Lophocebus aterimus.

The present paper deals with the use of a new technique in type II human pancreatic elastase studies based on the use of a reversible immune-adsorbent which provides a unique specificity. According to the type of ligand linked on activated Sepharose, the elastase or its antibody in Rabbit could be obtained, in very pure form, in a one step process. The anti-human pancreatic elastase II, which specifically inhibits the enzyme, may be used in therapy whenever the elastase-inhibitor system becomes unbalanced.

A single-eye irradiation of 10 Gy (0.8 Gy. min-1) induces impairments of the electrical responses of the rabbit retina in dark adaptation. These are associated with reversible alteration of the photoreceptors and the preganglionic neurons and a disturbance of all the mechanisms of adaptation. Possible relationships between these functional alterations and the effects of irradiation are discussed.

In the Cat, the development of an electrocortical rhythm at 40 Hz (fast "mu" rhythm) is observed in the parietal cortex whenever the subject immobilizes itself in an attitude of focused attention (e.g. when watching a mouse). This rhythm, as well as the accompanying behaviour, seems to be under the control of a dopaminergic mechanism originating from the ventral tegmental mesencephalic area (cellular dopaminergic group A 10).

By studying serologically the appearance of HLA-DR determinants on T lymphocytes activated by a mixed lymphocyte culture, we have been able to demonstrate the existence of a new class of antigenic determinants distinct from classical HLA-DR antigens. Indeed, some monospecific anti-DR sera were cytotoxic from some alloactivated T cells, though not directed against their HLA-DR specificity. The absorption of these anti-sera on B lymphocytes bearing the HLA-DR antigen against which they were directed, did not remove their reactivity on alloactivated T lymphocytes. The absorption of the same anti-sera on activated T lymphocytes did not affect their anti-DR reactivity. This study shows the existence of new antigenic determinants expressed by T lymphocytes during their activation: alloactivated T lymphocyte antigens (AATL).