[Agraphia of the left hand--its characteristics and mechanism of development]

We observed 62 y.o. right-handed woman, whose truncus of corps callosum was damaged by infarction of left anterior cerebral artery, that was verified by coronal CT scan finding. She was apraxic and agraphic only with left hand. We examined the characteristics of her unilateral left agraphia from the point of quantitative and qualitative views. These analysis seemed to reveal three main characteristics of unilateral left agraphia of this patient. These were as follows; 1) productive, 2) neographic and 3) iterative. Another important feature of this patient was the mute state during her left-hand writing. Her left agraphia could not explained by apraxic factor, because her copying capacity was remarkably preserved in comparison with her dictation or written naming ability. Furthermore, this agraphia was not aphasic because her right-hand writing was almost intact. We agreed with Yamadori who insisted that this type of agraphia was neither apraxic nor aphasic, but the particular third agraphia which was named as "disconnection agraphia". We considered that the mute state during her left-hand writing might some kind of transient aphasia, which may reflect the functional disturbance of left hemisphere, and the reduced energy in the left hemisphere could increase the activity of right hemisphere. Partial interhemispheric disconnection might induce transient "linguistic anosognosia" in this patient. We believe that these transient hyperactivity and transient linguistic anosognosia could generate above mentioned characteristics of her left agraphia; productive, neographic and iterative.

[Heterogeneity of bucco-facial apraxia]

The authors have studied the bucco-facial apraxia (BFA) in 20 aphasic patients, examining 10 isolated oral gesture (IOG) and 10 combined oral gesture (COG). The heterogeneity of the BFA is indicated by the qualitative analysis of the types of errors in COG in relation to IOG. It is probably that the BFA due to the posterior lesions might base on the motor programming disorders of oral gestures, and that the BFA due to the anterior lesions on the motor realization disorders of oral gestures. It remains unsolved whether there is a continuity or some varieties between two types of BFA.

Formation of the two-dimensional hexagonal lattice of bacteriorhodopsin in reconstituted brown membrane

The aggregation state of reconstituted bacteriorhodopsin molecules in the brown membrane has been investigated by X-ray diffraction and CD spectra. It has been confirmed that reconstituted bacteriorhodopsin molecules form the hexagonal lattice spontaneously whereas bacterioopsin molecules do not.

Fractionation of rhodopsin and other components in the rod outer segment membrane by ammonium sulfate salting-out

Purified bovine rod outer segment membrane was solubilized in a mixture of 1.5% cholic acid/20% saturated ammonium sulfate and 0.05 M phosphate buffer (pH 7.5). The solubilized rod outer segment membrane was fractionated with ammonium sulfate and 70--90% of rhodopsin (A278/A498= 1.6--1.9) was recovered in the fraction of 50 to 60% saturation with ammonium sulfate, giving a highly concentrated solution of purified rhodopsin (A1CM 498 = 83). By the method of ammonium sulfate salting-out, the solubilized rod outer segment membrane was divided into several fractions without a loss of components. The components in each fraction were examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Rhodopsin and opsin amounted to 93% of the total protein in the membrane. Other proteins with molecular weights of 46 000, 52 000, 56 000, 70 000, 95 000, 105 000, 130 000 and 270 000 were also detected. Most of phospholipids in the rod outer segment membrane remained in the supernatant above 60% saturation with ammonium sulfate.