Reactivated response of blink reflex in the cat

Three reflex responses in the orbicularis oculi muscles were observed by electrical stimulation of the trigeminal nerve in lightly anesthetized or conscious cats. The third response, following the first and second responses, was concluded as being a "reactivated response" of the blink reflex as it was set up by the trigeminal afferent input evoked by the palpebral movement of the preceding blink. The reasons for this were as follows: 1) the third response disappeared on administration of muscle relaxants and 2) was enhanced by touching the palpebral hair; 3) the palpebral movement activated the afferent discharges of the trigeminal exteroceptors which were strong enough to yield the reflex responses and 4) the latency of the first reflex response by the palpebral movement corresponded to the time lag between the preceding large reflex response and the third response; 5) the third response was hardly suppressed at all until the first response disappeared over a period of maximum reflex suppression following the conditioned stimulation of the trigeminal nerve.

Cranial chondromyxoid fibroma. Case report

A case of chondromyxoid fibroma of the frontal bone in a 15-year-old girl is presented. This is a benign tumor, but should be excised widely enough to include a rim of normal bone, otherwise it may recur or even undergo malignant transformation.

An easy quantitative cytotoxicity assay using a Coulter Counter

A rapid and reproducible cytotoxicity assay using an electronic particle counter, such as a Coulter Counter, is described. With anti-BAtheta antiserum and mouse thymocytes as target cells, comparable, but more objective results than those by the ordinary dye exclusion method were obtained in a short time. The procedure is very simple: Cells in a plastic multi-well plate are first exposed to antibody and complement or other cytolytic conditions and then Pronase E is added to each well to digest dead cells completely. Then the nuclei of remaining viable cells are liberated from the cytoplasm and cell debris by solubilization with Zap-Oglobin and counted in the counter. Under these conditions, contaminating erythrocytes do not cause interference, because they are completely solubilized with Zap-Oglobin. This technique should be useful for measurements on numerous samples, such as in monitoring chromatograms of cytotoxic activity and titrating antibody and complement.

Hip abnormalities in cerebral palsy: radiological study

A total of 237 hips of children with cerebral palsy were examined annually for three years. The severely involved spastic children and those who had never stood were more susceptible to hip abnormality. Apparent coxa valga (whose phenotype consists more of anteversion and less of true coxa valga) is closely related to the hip abnormality.

Plasminogen-plasmin system IX. Specific binding of tranexamic acid to plasmin

Interactions between tranexamic acid and protein were studied in respect of the antifibrinolytic actions of tranexamic acid. Tranexamic acid did neither show any interaction with fibrinogen or fibrin, nor was incorporated into cross-linked fibrin structure by the action of factor XIII. On the other hand, tranexamic acid bound to human plasmin with a dissociation constant of 3.5 X 10-5 M, which was very close to the inhibition constatn (3.6 X 10-5 M1 for this compound in inhibiting plasmin-induced fibrinolysis. The binding site of tranexamic acid on plasmin was not the catalytic site of plasmin, because TLCK-blocked plasmin also showed a similar affinity to tranexamic acid (the dissociation constant, 2.9-4.8 x 10-5m). in the binding studies with the highly purified plasminogen and TLCK-plasmin preparations which were obtained by affinity chromatography on lysine-substituted Sepharose, the molar binding ratio was shown to be 1.5-1.6 moles tranexamic acid per one mole protein. On the basis of these and other findings, a model for the inhibitory mechanism of tranexamic acid is presented.