Effect of charcoal-broiled beef on phenacetin metabolism in man

When charcoal-broiled beef was fed to human volunteers, who were then given phenacetin orally, the concentration of phenacetin in the plasma was lowered, but its half-life in the plasma was not changed. The data suggest that feeding charcoal-broiled beef enhances the metabolism of orally administered phenacetin in the intestine or during its first pass through the liver, or both.     

Musculocutaneous neurectomy for spastic elbow flexion in non-functional upper extremities in adults

The charts of twenty-nine patients who had undergone thirty musculocutaneous neurectomies for acquired spasticity of the elbow in a non-functional upper extremity were reviewed. The most common causes of the spasticity were cerebrovascular accident (59 per cent) and head injury (24 per cent). The aims of the operation were to increase the patient's capacity for self-care and to improve ambulation, personal hygiene, and appearance. Patients who had 30-degree flexion contractures preoperatively did not require a cast postoperatively; those who had 30 to 75-degree flexion contractures preoperatively required a cast postoperatively; and patients who had flexion contractures of more than 75 degrees preoperatively required a concomitant release of soft tissue in the elbow and application of a cast postoperatively. One patient who was operated on to improve appearance had no active elbow flexion postoperatively and was regarded as having a poor result. Musculocutaneous neurectomy is a safe, reliable procedure for treating the spastic elbow in the non-functional upper extremity.     

Lipids of the cottonseed. III. Perchloric acid ashing of lipids for the determination of phosphorus

1. Cottonseed oil is effectively oxidized with a mixture of perchloric and nitric acids in connection with the determination of phosphorus by the Fisk and Subbarow method.
2. The development of the molybdenum blue in the procedure is independent of the acid content in the reducing medium up to 0.5 normal.
3. The presence of perchloric acid does not interfere with the development of the molybdenum blue.
4. The phosphorus content of cottonseed extracts depends on the nature of the solvent. The quantities obtained varied from 0.0071 to 0.117%.
5. A phospholipid containing 3.73% phosphorus was isolated from cottonseed.

     

Evidence that different mechanisms underlie smooth muscle relaxation to nitric oxide and nitric oxide donors in the rabbit isolated carotid artery

1. The endothelium-dependent relaxants acetylcholine (ACh; 0.03-10 microM) and A23187 (0.03-10 microM), and nitric oxide (NO), applied either as authentic NO (0.01-10 microM) or as the NO donors 3-morpholino-sydnonimine (SIN-1; 0.1-10 microM) and S-nitroso-N-acetylpenicillamine (SNAP; 0.1-10 microM), each evoked concentration-dependent relaxation in phenylephrine stimulated (1-3 microM; mean contraction and depolarization, 45.8+/-5.3 mV and 31.5+/-3.3 mN; n=10) segments of rabbit isolated carotid artery. In each case, relaxation closely correlated with repolarization of the smooth muscle membrane potential and stimulated a maximal reversal of around 95% and 98% of the phenylephrine-induced depolarization and contraction, respectively. 2. In tissues stimulated with 30 mM KCl rather than phenylephrine, smooth muscle hyperpolarization and relaxation to ACh, A23187, authentic NO and the NO donors were dissociated. Whereas the hyperpolarization was reduced by 75-80% to around a total of 10 mV, relaxation was only inhibited by 35% (n=4-7 in each case; P<0.01). The responses which persisted to ACh and A23187 in the presence of 30 mM KCl were abolished by either the NO synthase inhibitor L-NG-nitroarginine methyl ester (L-NAME; 100 microM) or the inhibitor of soluble guanylyl cyclase 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 10 microM; 10 min; n=4 in each case; P<0.01). 3. Exposure to ODQ significantly attenuated both repolarization and relaxation to ACh, A23187 and authentic NO, reducing the maximum changes in both membrane potential and tension to each relaxant to around 60% of control values (n=4 in each case; P<0.01). In contrast, ODQ almost completely inhibited repolarization and relaxation to SIN-1 and SNAP, reducing the maximum responses to around 8% in each case (n=3-5; P<0.01). 4. The potassium channel blockers glibenclamide (10 microM), iberiotoxin (100 nM) and apamin (50 nM), alone or in combination, had no significant effect on relaxation to ACh, A23187, authentic NO, or the NO donors SIN-1 and SNAP (n=4 in each case; P>0.05). Charybdotoxin (ChTX; 50 nM) almost abolished repolarization to ACh (n=4; P<0.01) and inhibited the maximum relaxation to ACh, A23187 and authentic NO each by 30% (n=4-8; P<0.01). Application of ODQ (10 microM; 10 min) abolished the ChTX-insensitive responses to ACh, A23187 and authentic NO (n=4 in each case; P<0.01 5. When the concentration of phenylephrine was reduced (to 0.3-0.5 microM) to ensure the level of smooth muscle contraction was the same as in the absence of potassium channel blocker, ChTX had no effect on the subsequent relaxation to SIN-1 (n=4; P>0.05). However, in the presence of tone induced by 1-3 microM phenylephrine (51.2+/-3.3 mN; n=4), ChTX significantly reduced relaxation to SIN-1 by nearly 50% (maximum relaxation 53.2+/-6.3%, n=4; P<0.01). 6. These data indicate that NO-evoked relaxation of the rabbit isolated carotid artery can be mediated by three distinct mechanisms: (a) a cyclic GMP-dependent, voltage-independent pathway, (b) cyclic GMP-mediated smooth muscle repolarization and (c) cyclic GMP-independent, ChTX-sensitive smooth muscle repolarization. Relaxation and repolarization to both authentic and endothelium-derived NO in this large conduit artery appear to be mediated by parallel cyclic GMP-dependent and -independent pathways. In contrast, relaxation to the NO-donors SIN-1 and SNAP appears to be mediated entirely via cyclic GMP-dependent mechanisms.     

Stimulation of RNA and protein synthesis in isolated chondrocytes by human serum

The stimulation of isolated chicken embryo chondrocytes was studied by measuring the incorporation of [3H]uridine and [3H]leucine into cold trichloroacetic acid precipitable material after exposure of the chondrocytes to serum. The doseresponse relationships for the incorporation of uridine and leucine were similar to that of thymidine previously demonstrated. Exposure of the cells to serum-containing buffer for 15 min sufficed both for the stimulation of incorporation into the cells and for the depletion of 28% of the stimulating activity from the medium. Stimulation persisted for at least 17 h after removal of the serum. Studies where actinomycin D was added to inhibit RNA synthesis suggested that prior RNA synthesis was required for most of the stimulation of protein synthesis by serum factors.     

Design Innovations in Personal Computers

There is little question that the current enthusiasm in personal computing was catalyzed by the introduction of the MITS Altair computer kit in January 1975. This computer kit demonstrated by its cost (originally less than $400) that individuals could now afford a computer. And by its design the Altair established a standard bus structure for the personal computing industry.