Fractures of the femur in newborn calves.

A retrospective study of femoral fractures in 77 calves revealed that most occurred in the femoral shaft or in the proximal physis, with thin cortices and periosteal stripping significant problems in fractures of the femoral shaft. Most cases were related to forced extraction, with more left femurs being affected than right. The existence of concurrent disease reduced the success rate by 50% and, when significant additional trauma was present, no calves survived. When all cases were considered regardless of condition, the "longterm" success rate was 43%.

Calcium ion stimulated endogenous protein kinase catalyzed phosphorylation of basic proteins in myelin subfractions and myelin-like membrane fraction from rat brain.

Polypeptide composition and endogenous phosphorylation were investigated in the subfractions of rat brain myelin isolated by either discontinuous or continuous sucrose density gradient centrifugation of myelin. Similarly, a myelin-like membrane fraction (SN4) was also studied. Observations were made that strongly indicated the presence of a calcium-stimulated protein kinase in a highly purified myelin preparation and which exclusively phosphorylated myelin basic proteins of the membrane preparation. Adenosine cyclic 3',5'-phosphate (cAMP) stimulated kinase on the other hand was found to be considerably enriched in the myelin-like membrane fraction. Although this latter enzyme is also capable of phosphorylating the basic proteins, its effect was at least 5 times weaker compared to the calcium-stimulated myelin protein kinase. Within the gradient subfractions there appeared a close relation between the amount of basic proteins and their calcium-stimulated phosphorylation; a similar relationship, however, was not obtained in the case of cAMP-dependent phosphorylation of myelin basic proteins. The former (i.e., Ca2+-stimulated phosphorylation) was found to require a protein factor that functionally resembled calmodulin. The results thus raises an interesting possibility of the presence of calmodulin-like proteins and a calcium-stimulated protein kinase in adult myelin membrane from mammalian brain, both of which have been hitherto unrecognized constituents of myelin membranes.

Differential effects of benztropine and desipramine on the high affinity uptake of paratyramine in slices of the caudate nucleus and hypothalamus.

The effect of benzotropine and desipramine on the uptake of dopamine and p-tyramine was studied in slices of caudate and hypothalamus. In the hypothalamus, of the various combinations of drugs and amines, desipramine inhibited p-tyramine uptake most effectively. In the caudate, benzotropine inhibited dopamine uptake most effectively. It is suggested that in the caudate, p-tyramine may possess its own unique transport system distinct from that utilized by dopamine which is inhibited by benzotropine.

Calcium ion-stimulated phosphorylation of myelin proteins.

Myelin isolated from the central and peripheral nervous system contains a Mg2+-dependent protein kinase that catalyses phosphorylation of myelin-specific proteins. This phosphorylation is markedly stimulated by Ca2+ but not by cyclic AMP. Evidence was obtained that suggested an involvement of calmodulin-like protein in the stimulatory effects of Ca2+ on myelin phosphorylation.

Calcium ion stimulated endogenous protein kinase catalyzed phosphorylation of peripheral and central nerve myelin proteins: comparison between normal and genetically dystrophic mouse.

Myelin isolated from the peripheral (PNS) and central nervous system (CNS) of mouse contained a protein kinase which catalyzed phosphorylation of myelin proteins. In the case of CNS myelin, small and large basic proteins were phosphorylated whereas in the case of PNS myelin, a glycoprotein (Po) as well as other basic proteins (P1 and P2) were phosphorylated. Ca2+, but not adenosine 3',5'-monophosphate (cyclic AMP), markedly (5- to 10-fold) stimulated phosphorylation of PNS and CNS myelin proteins. There was no difference between the normal and dystrophic mouse CNS myelin phosphorylation. However, a marked decrease in the cauda equina PNS myelin phosphorylation ofthe dystrophic mouse was observed. Interestingly, the dystrophic sciatic nerve myelin phosphorylation, compared to normal, was higher.

Calcium ion stimulated endogenous protein kinase catalyzed phosphorylation of peripheral nerve myelin proteins.

Myelin isolated from the rat peripheral nervous system (sciatic nerve and cauda equina) contained Mg2+-dependent protein kinase that phosphorylated myelin polypeptides. Ca2+, in micromolar concentrations, markedly stimulated phosphorylation (half-maximal stimulation at 5 microM (free) Ca2+) but at higher concentrations (greater than 100 microM Ca2+) it caused inhibition. In the presence of Triton X-100, phosphorylation (+/-Ca2+) of myelin was increased and Ca2+ caused up to a 10-fold increase in phosphorylation. Among the myelin polypeptides, P0 (Mr, 28 000), a major glycoprotein, accounted for nearly 60% of the total phosphate incorporated into the myelin and Ca2+ markedly promoted phosphorylation of P0. Phosphorylation of other myelin polypeptides, P2 (Mr, 16 000), Y (Mr, 26 000), and P1 (Mr, 20 000), and the Ca2+-stimulatory effect on phosphorylation of these were also evident. Cyclic AMP (or other cyclic nucleotides) failed to show any significant stimulatory effect on myelin phosphorylation.

Uptake of para-tyramine and meta-tyramine into slices of the caudate nucleus and hypothalamus of the rat.

The kinetics of the uptake of p-tyramine, m-tyramine, and dopamine were investigated in slices of the hypothalamus and striatum of the rat in the presence of nialamide. When uptake was analyzed by a least-squares fit to a Lineweaver-Burk plot, each amine appeared to be concentrated by both a "low"-affinity and a "high"-affinity system in both brain regions. The obtained Km and Vmax values for the "high"-affinity uptake system for each amine in both brain regions were similar. In general terms, the uptake systems in the striatum exhibited larger Km and Vmax values, with the velocity of uptake being in the order dopamine less than m-tyramine less than p-tyramine. 2,4-Dinitrophenol (DNP) and ouabain reduced all uptakes in the caudate, but reduced only the "high"-affinity uptake of m-tyramine and the "low"-affinity uptake of dopamine in the hypothalamus.