Clinical experience using a small-gauge needle for arterial puncture

The present study was undertaken to ascertain the feasibility of using a 25-gauge needle for arterial punctures. A total of 11,500 arterial punctures were performed over the past four years by this technique without any major complication. Repeated arterial punctures were well tolerated by all patients, and the necessity for indwelling arterial catheters was almost totally eliminated during this period of study.     

The presence of aromatic L-amino acid decarboxylase in certain intestinal nerve cells

The presence of aromatic 1-amino acid decarboxylase (AADC) in nerve cell bodies of the intrinsic plexuses of the guinea-pig small intestine was demonstrated by incubating segments of intestine with 1-dopa in the presence of an inhibitor of monoamine oxidase, pargyline. After such incubation, some nerve cell bodies gave a fluorescence histochemical reaction indicative of the presence of a decarboxylated product of 1-dopa, probably dopamine. No fluorescence reaction occurred in the unincubated control or if the inhibitor of AADC, RO 4-4602, was included in the incubation mixture. The AADC-containing cell bodies apparently do not take up and store dopamine, because no fluorescence could be detected after incubation with dopamine and a monoamine oxidase inhibitor. The AADC-containing cells were found in about half of the ganglia of the submucous plexus of the guinea-pig small intestine, but were considerably less frequent in the myenteric plexus. They were also found in the other areas examined in this study, that is, in both enteric plexuses of the guinea-pig distal colon and of the small intestines of rabbits and rats.     

Substrate inhibition of beta-lactamases, a method for predicting enzymatic stability of cephalosporins

Selected cephalosporins, including cefamandole, cephaloridine, cephaloglycin, and cefoxitin, were examined for their ability to inhibit the enzymatic activity of and act as substrates for beta-lactamases produced by Enterobacter cloacae and Staphylococcus aureus. Enzyme inhibition was determined by Michaelis-Menten kinetic measurements and by a spot plate assay using a chromogenic substrate (Glaxo compound 87/312). These two methods provide comparable estimates of kinetic parameters. Inhibition of beta-lactamase, as measured by these two methods, was generally found to correlate with resistance to hydrolysis and is proposed as a preliminary method of assessing susceptibility of cephalosporins to beta-lactamase hydrolysis. Four 7-alphaOCH(3), 7-alphaH cephalosporin analogue pairs were also examined. The presence of the 7-alphaOCH(3) substituent invariably resulted in reduced susceptibility to enzymatic hydrolysis, regardless of the other C7 substituent. The 7-alphaOCH(3) compounds were also better inhibitors than were their 7-alphaH analogues, with the exception that 7-alphaOCH(3) compounds having C7 adipic acid substituents were less inhibitory to the S. aureus enzyme than were the corresponding 7-alphaH analogues. Response of these two enzymes to 7-alphaOCH(3) and 7-alphaH cephalosporins suggests that beta-lactamase hydrolysis of these compounds involves attack at the alpha side of the betalactam ring.     

Partial purification of rabbit aorta contracting substance-releasing factor and inhibition of its activity by anti-inflammatory steroids

Rabbit aorta contracting substance-releasing factor (RCS-RF) is found in perfusates from guinea pig lungs during anaphylaxis. It has been identified as a small peptide which releases arachidonic acid from lung tissue, thus generating prostaglandin endoperoxides and tbromboxanes and causing bronchocconstriction. Anti-inflammatory steroids block the release of arachidonate by RCS-RF. In this activity their relative potency is very similar to their relative anti-inflammatory potency, suggesting that the two actions may be related.     

Renal responses of Australian lungfish to vasotocin, angiotensin II, and NaCl infusion

The Australian lungfish (Neoceratodus forsteri) responds to intravenous injections of 0.63 ng/kg or more of arginine vasotocin with increased dorsal aortic blood pressure, inulin clearance, urine flow, and tubular rejection of Na+. Single injections of 1 ng/kg or more of angiotensin II or norepinephrine also increase dorsal aortic pressure but do not cause consistent diuresis and natriuresis, Continuous infusions of angiotensin II or repeated injections of norepinephrine produce sustained hypertension and more modest diuresis and natriuresis than are seen after injections of arginine vasotocin that cause less hypertension. Infusions of isosmolar or hyposmolar NaCl solutions increase blood pressure, inulin clearance, urine flow, and tubular Na+ rejection in a manner resembling the response to argininge vasotocoin injections. These data are consistent with the hypothesis that arginine vasotocin is released in response to volume expansion in lungfishes and that it may act on the kidney as a diuretic and natriuretic hormone. They do not rule out a more direct action of expansion on renal functions.     

Arbitration agreements and your malpractice coverage

With new legislation and favorable case law developments, many providers of health care services are turning to binding arbitration agreements as a partial solution to the medical malpractice crisis. Existing data indicate tremendous advantages can be gained from the use of such agreements, if they are carefully drawn to comply with new law, tailored to the particular situation in which they will be used and coupled with appropriate procedures to secure the intended benefits. Arbitration is not a substitute for insurance, but if a provider has taken the calculated risk of forgoing insurance he should not be without a carefully drawn binding arbitration agreement.     

Pig prothrombin: purification and properties

A procedure for the preparation of highly purified pig prothrombin is described. Compared to the initial clotting activity of the starting plasma, this protein was purified 776 times with a final yield of 8 per cent. The purified zymogen showed a specific activity of 1,460 NH units/mg of protein , a molecular weight of 65,000 as determined by SDS-polyacrylamide disc gel electroesis, E 1.0 mg/ml 1.0 cm, 280 nm = 1.45 at pH 7.0 and the following amino acid composition: Asx 51, Thr 38, Glx 62, Pro 23, Gly44, Ala 25, Half-Cys 30, Val 35, Met 3, Ile 30, Leu 32, Tyr 19, Phe 22, Lys 36, His 8, Arg 28, and Trp 13, which accounts for a minimum molecular weight of 59,370 (carbohydrates not computed). Alanine was found as the only N-terminal residue. Carboxypeptidases A and B failed to release any C-terminal residue. By hydrazinolysis however 0.4 mole of serine was released per mole of prothrombin. The activation of crude and chromatographed pig prothrombin was investigated.