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Biomedical subjects

W Miles

Publications and source records attributed to W Miles.

7 recordsLinked to original sources

Adenosine for paroxysmal supraventricular tachycardia: dose ranging and comparison with verapamil. Assessment in placebo-controlled, multicenter trials. The Adenosine for PSVT Study Group.

OBJECTIVE: To assess the safety and efficacy of intravenous adenosine in terminating acute episodes of paroxysmal supraventricular tachycardia. DESIGN: Two prospective, double-blind, randomized, placebo-controlled trials to evaluate dose response in patients receiving adenosine and to compare the effects of adenosine with those of verapamil. PATIENTS: A total of 359 patients with a tachycardia electrocardiographically consistent with paroxysmal supraventricular tachycardia were entered into the two protocols. Patients subsequently found to have arrhythmias other than paroxysmal supraventricular tachycardia were excluded from the efficacy analysis. INTERVENTIONS: The first protocol compared sequential intravenous bolus doses of 3, 6, 9, and 12 mg of adenosine to equal volumes of saline. In the second protocol, patients received either 6 mg and, if necessary, 12 mg of adenosine or 5 mg and, if necessary, 7.5 mg of verapamil. MEASUREMENTS AND MAIN RESULTS: When data are expressed in terms of cumulative response in eligible patients, intravenous adenosine terminated acute episodes of paroxysmal supraventricular tachycardia in 35.2%, 62.3%, 80.2%, and 91.4% of patients who received maximum doses of 3, 6, 9, and 12 mg, respectively, in a four-dose sequence, whereas 8.9%, 10.7%, 14.3%, and 16.1% of patients responded to four sequential placebo doses (P less than 0.0001). In the second trial, cumulative response rates after 6 mg followed, if necessary, by 12 mg of adenosine were 57.4% and 93.4%, and after 5 mg followed, if necessary, by 7.5 mg of verapamil were 81.3% and 91.4%. The average time after injection to termination of tachycardia by adenosine was 30 seconds. Adenosine caused adverse effects in 36% of patients, but they lasted less than 1 minute and were usually mild. CONCLUSIONS: Adenosine in graded doses up to 12 mg rapidly and effectively terminates acute episodes of paroxysmal supraventricular tachycardia in which the atrioventricular node is an integral part of the re-entrant circuit. The overall efficacy of adenosine is similar to that of verapamil, but its onset of action is more rapid. Adverse reactions to adenosine are common but are minor and brief.

Acute Disease

Soft tissue trauma.

With any soft tissue injury that involves a great deal of skin loss, the basic goals of therapy are edema control and management of scar tissue. The key to treatment is early intervention with the use of elevation, exercise, pressure, and splinting to prevent the all too frequent soft tissue and joint contractures. Management is not short-term as maturation of the scar can take up to 1 year. Experienced evaluation and consistency in carrying out the therapeutic program are necessary if full function is to be restored.

Adolescent

Gas-liquid chromatographic-mass spectrometric determination of alpha- and beta-naphthylamines in FD&C Red No. 2 (amaranth).

A method is described for the simultaneous quantitation of trace amounts of alpha- (alpha-NA) and beta-naphthylamines (beta-NA) with detectability in the 0.1 ppb range and sensitivity of 50 picomoles in certified food grade amaranth (FD&C Red No. 2; C.I. Food Red 9; CI 16185). The amaranth sample is extracted with benzene, and the evoporated residue is derivatized with perfluorooctanoic anhydride. The resulting derivatives are separated by gas-liquid chromatography and identified and quantitated by mass spectrometric monitoring of the m/e at 539.04. The method was used for quantitation of alpha-NA and beta-NA in randomly chosen samples of amaranth. Of 11 samples from different manufacturers, 5 were free of the beta-isomer; the remaining samples contained up to 1.2 ppb beta-NA. The concentration of alpha-NA ranged from no detectable amount to 970 ppb; the majority of the samples contained less than 7 ppb.

1-Naphthylamine

N-Nitrosodiethanolamine in synthetic cutting fluids: a part-per-hundred impurity.

N-nitrosodiethanolamine has been found to be present at a concentration of 0.02 to 3 percent in several brands of synthetic cutting fluids. Its identity was confirmed by three independent techniques: (i) by measuring the retention times on two different high-performance liquid-chromatography columns, (ii) by dehydration to N-nitrosomorpholine, and (iii) by preparation of the O-methyl ether derivative.

Environmental Pollutants

Implications of inorganic/organic interconversion on fluxes of arsenic in marine food webs.

An organic form of arsenic is commonly encountered in marine organisms; in greysole and shrimp, it accounted for all arsenic found in muscle tissue. It has been isolated from flounder tissue by two independent procedures; it was hydrophilic, cationic, and was not decomposed to inorganic arsenic by hot nitric and sulfuric acids. NMR spectroscopy indicated all nonexchangeable protons to be equivalent; they behaved more like N-methyl protons than As-methyl protons. High-resolution mass spectroscopy from a heated probe yielded a spectrum corresponding to tetramethylarsonium (AsMe4+); the authentic ion, however, had TLC and ion-exchange behavior different from that of the natural product. Infrared spectrometry likewise produced conflicting or uninterpretable data. Decomposition of the compound for analytical purposes was accomplished by dry ashing under oxidizing conditions. Sea urchins, like trout, converted arsenic to an organic form, but to a more limited degree. Arsenic found naturally in sea urchins and in a species of macroalga was also organic. In individual containers, sea urchins were fed on the alga for 7 weeks. During this time they consumed 0.203 +/- 0.075 mg total As and excreted only 0.036 +/- 0.015 mg as feces. Measurement of inorganic As in the seawater did not account for the discrepancy, but measurements of total As did (0.202 +/- 0.095 mg). Sea urchins, like humans, appear to be able to rapidly excrete these organic forms of arsenic.

Animals