The location and function of cytochrome c2 in Rhodopseudomonas capsulate membranes

Two fractions of membrane preparations, a heavy and a light one were isolated from mildly broken Rhodopseudomonas capsulata cells. The light fraction which contained vesicles similar to the regular chromatophores obtained by sonication and a heavy fraction which appeared in electron micrographs to consist of cell fragments which were designated as heavy chromatophores and were composed of broken cell envelopes containing closely packed vesicles enclosed within the cytoplasmic membrane. Both types of chromatophores catalyzed photophosphorylation. However, cytochrome c2 could be washed out only from the heavy chromatophores. Photophosphorylation activity which was lost by the removal of the cytochrome could be restored by addition of either cytochrome c2 or phenazine methosulphate. Light induced proton efflux in heavy chromatophores in contrast to proton influx in regular chromatophores. The washed heavy chromatophores did not lose the light induced proton movement. Light induced quenching of 9-aminoacridine and atebrin fluorescence in chromatophores, while the fluorescence was enhanced in the heavy chromatophores. The washing did not affect the fluorescence changes of the heavy chromatophores but caused a reduction of the steady state of the carotenoid absorbance shift. It is suggested that the membrane in the heavy chromatophores is oriented inside out with respect to the membrane in regular chromatophores. Cytochrome c2 which is attached to that side of the membrane facing the outside medium could be removed from the heavy chromatophors and reconstituted to them. The role of cytochrome c2 in photophosphorylation is discussed.

Cancer of the thyroid following radium application to the neck

A young patient, suffering from thyroid carcinoma 24 years after radium treatment of the neck, is presented. The cancer appeared in the area which has been irradiated. In the present case, the thyroid was exposed to a relatively low dose of radiation. The importance of ionizing radiation and its carcinogenic effect in the juvenile thyroid are discussed.

Normal and Pathological Parameters of the Liver as Measured on the Scannogram

Sept paramètres différents en longeur et largeur ont été mesurés dans 100 scintigrammes du foie normaux et 100 scintigrammes pathologiques. Touts les donnés ont été comparés statistiquement entre eux. Des comparaisons entre les sexes on été effectués. Des détails sont donnés sur l’âge, le sex le diagnostique et les tests biochimiques de fonction du foie dans les deux groupes. A l’exception de deux, tous les paramètres montrent des différences statistiques entre le groupe normal et le groupe pathologique. On n’a pas observé des différences de sexe.

L’usage de ces mesures comme critère objectif en addition à l’impression subjectif du médecin expériencé sont importants pour arriver à un diagnostique plus sûr.

Thyroid Dimensions as Measured on the Scintigram

Thyroid scans were performed on 61 patients. Forty-one were females and 20 males. Seven patients were hyperthyroid, 43 euthyroid and 11 hypothyroid.

It was found that in most patients the right lobe was larger and wider than the left lobe. Males had usually larger glands than females. The upper pole of the right lobe extended higher in the neck than the left lobe.

The value of these findings in relation to treatment of thyrotoxicosis is discussed.