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(i) Myosin from chicken gizzards was purified by a modification of an earlier procedure ( M. N. Malik, 1978, Biochemistry 17 , 27–32). When this myosin, as well as that prepared by the method of A. Sobieszek and R. D. Bremel (1975, Eur. J. Biochem. 55 , 49–60), was analyzed by gradient slab gel using the discontinuous buffer system of Neville (1971, J. Biol. Chem. 246 , 6328–6334), a closely spaced doublet in the heavy chain and four light chains were observed as opposed to one heavy chain and two light chains with the method of Weber and Osborn (1969, J. Biol. Chem. 244 , 4406–4412). These findings raise the possibility of the existence of myosin isoenzymes in smooth muscle. (ii) The purified gizzard myosin was found to be free of kinase and phosphatase. Phosphorylation or thiophosphorylation of myosin was observed only by exogenously adding kinase. A maximum of 1.2 mol of 32 P/mol of myosin and 2.3 mol of 35 S/mol of myosin were obtained. The actin-activated ATPase activity depended upon the extent of thiophosphorylation of myosin; a four- to fivefold increase in the activity was observed when myosin was fully thiophosphorylated. Thiophosphorylated myosin was found to be more stable than phosphorylated myosin.

A calcium-activated neutral protease (CANP) has been purified 2,800 fold, to near homogeneity, from human platelets. The purification procedure involved ammonium sulfate fractionation of the platelet cytosol followed by chromatography on Sephacryl S-200, DEAE-Sephacel, Agarose-Hexylamine, Agarose-Octylamine and alpha-casein-Sepharose 4B affinity gel. The protease consisted of two polypeptides of Mr = 74,000 and 28,000 as judged on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It hydrolyzed [methyl-14C] alpha-casein at a significant rate of 37 degrees C which was, therefore, used as an exogenous substrate. Microtubules and intermediate filament proteins were also susceptible to hydrolysis by the purified protease. It attained maximum activity at 0.06 uM CaCl2 and displayed two pH maxima: one at 5.5 and the other at 6.5. The protease was fully active in the presence of MnCl2 and was about 75% active with BaCl2 and SrCl2. Among the actinomycete protease inhibitors, leupeptin, antipain and pepstatin, the order of inhibition was: leupeptin greater than antipain greater than pepstatin. The protease was also inhibited by sulfhydryl modifying agents.

(i) The steady-state kinetic data obtained with purified gizzard and uterus smooth muscle myosins indicated the presence of a plateau region on the substrate-saturation curves. Hill plots of these data provided evidence for mixed positive and negative cooperative interactions. In contrast, when gizzard myosin was prepared according to the method of A. Sobieszek and R.D. Bremel (1975, Eur. J. Biochem. 55 , 49–60), the saturation curve in the presence of CaATP was hyperbolic and no cooperativity of the binding site(s) was discerned. However, in the presence of MgATP although the curve appeared hyperbolic the Hill plot of the data was biphasic with negative cooperativity at low MgATP concentration, (ii) When thiophosphorylated gizzard myosin was used for kinetic analysis, the plateau region in the presence of MnATP was eliminated from the saturation curve and this curve became hyperbolic. However, in the presence of MgATP, although the plateau was almost eliminated, the saturation curve was still biphasic with either no or greatly reduced negative cooperativity of binding sites at low MgATP concentrations but positive cooperativity of binding at high MgATP concentrations. In addition, the thiophosphorylation of myosin also increased the K m and V of MgATP and MnATP, thus indicating weaker affinity for these substrates with thiophosphorylated myosin. (iii) Gizzard myosin also hydrolyzed other nucleotides (the order of rates being CTP = ITP > ATP = UTP > GTP), therefore saturation kinetics using different nucleotides as substrates was also carried out. The saturation curves with each nucleotide were different i.e., hyperbolic with CTP, sigmoid with GTP, hyperbolic with biphasic Hill plot with ITP, and possessing plateau with UTP. In addition, it was observed that the kinetic pattern with each nucleotide was very sensitive to temperature and pH.

Infection of one member of a pair of parabiotic rats with various numbers of Trichinella spiralis larvae consistently produced myocarditis in the infected rat. No myocarditis was seen in any of the “uninfected parabionts”.

Each of a total of 106 five-week-old male Swiss albino mice divided into four groups, was inoculated with 6,400 Trichinella spiralis larvae subjected to various doses of roentgen radiation and their survival times recorded. One hundred per cent of the mice died if the larvae received no irradiation. None died if the larvae received 12,000 r. Approximately 85% of the mice died if the larvae were irradiated with 8,000 or 10,000 r.

We describe a patient with adult-type osteopetrosis presenting as carpal tunnel syndrome. Radiographs demonstrated sclerosis of the carpal bones, bone biopsy revealed wide bone spicules containing areas of cartilage, and electrophysiologic studies confirmed the diagnosis of median nerve entrapment in the carpal tunnel. Any condition which alters the size or shape of the carpal canal or its contents may result in median nerve compression.

Disruption of the right lobe of the liver with massive hemorrhage in a young woman taking oral contraceptives was successfully treated by right hepatolobectomy. Pathologic examination of the resected liver revealed evidence of hepatic vein thrombosis, necrosis, and hemorrhage. In the absence of any history of trauma, and in view of the pathologic findings, it is suggested that an association existed between the development of this entity and the use of oral contraceptives.

Three hundred thirty-three 5-week-old male Swiss albino mice divided into 11 equal groups in four experiments were inoculated with single graded doses of Trichinella spiralis larvae. Doses ranged from 400 to 51,200 larvae per mouse. Within the limits of these experiments, (1) the number of deaths among mice infected with increasing numbers of larvae increased until a mortality of one hundred per cent (100%) was reached. (2) Mean and median survival times varied inversely with the size of the inoculum. (3) There was no assurance that mean survival times for groups of homogeneous mice inoculated with equal dosages in different experiments would be comparable or precisely predictable.

values and suggest that platelet counts below 100,000 are abnormal. Garnet s showed that chlorothiazide freely crosses the placenta. Gjonness ~ found no adverse effects on electrolytes in the newborn infants of mothers receiving thiazide therapy. Leissring and Vorlicky s have reported a marked thrombocytopenia in an infant of a mother with severe pre-eclampsia, disseminated intravascular coagulation was thought to be responsible f o r the thrombocytopenia. The possibility exists that the thrombocyto~ penia in some infants of.~ mothers receiving thiazides might be a consequence of preeclampsia rather than of the thiazides. We were unable ~,~o~ any significant effect of maternal thiazides on the platelet counts of newborn infants. Although this series is small, the results suggest that therapeutic administration of thiazides to the pregnant woman has no predictable or common effect on the platelets of their infants. REFERENCES I. Oski, F. A., and Naiman, J. L.: Hematologic problems in the newborn, Philadelphia, 1966, W. B. Saunders Company. 2. Rodriguez, S. U., Leikln, S. L., and Hiller, M. C.: Neonatal thrombocytopenia associated with ante-partum administration of thiazide drugs, New Eng. J. Med. 270: 881, 1964. 3. Aballi, A. J., Puapondh, Y., and Desposito, F.: Platelet counts in thriving premature infants, Pediatrics 42: 685, 1968. 4. Fogel, B. J., Arias, D., and Kung, F.: PIatelet counts in healthy premature infants, J. PEmAT. 73: 108, 1968. 5. Kaplan, E., and Klein, S.: Thrombocytopenia and intestinal bleeding in premature infants, J. PEDIAT. 61: 17, 1962. 6. Garnet, J. O.: Placental transfer of chlorothiazide, Obstet. Gynec. 21: 123, 1963. 7. Gjonness, t-Ix Thiazide treatment in pregnancy, Acta Obstet. Gynec. Scand. 47: 404, 1968. 8. Leissring, J. C., and Vorlicky, L. N.: Disseminated intravascular coagulation in a neonate, Amer. J. Dis. Child. 115: 100, 1968.

Disulfiram and diethyldithiocarbamate, both inhibit the activity of alcohol dehydrogenase. We investigated whether another major dehydrogenase enzyme, lactate dehydrogenase was also inhibited by disulfiram