Semiautomated Method for the Analysis of Chlorpheniramine Maleate Tablets: Collaborative Study

A semiautomated method for the analysis of chlorpheniramine maleate tablets, which is based on the USP XIX general assay for salts of organic nitrogenous bases, was collaboratively studied by 6 laboratories. Collaborators were supplied with 4 composites from 4 manufacturers. In the method, the active ingredient is dissolved in dilute HC1, sampled, made basic with dilute NaOH, and extracted with isooctane. The isooctane phase is resampled and the drug is re-extracted into dilute HCL. The absorbance of the acidic aqueous solution is measured at 265 nm. The Associate Referee assayed the collaborative samples to compare the semiautomated and USP XIX methods, and found close agreement in the results from the 2 methods. In the collaborative study of the semiautomated method, there was excellent agreement of the results obtained by the collaborators. The coefficients of variation ranged from 0.46 to 2.24%. The method has been adopted as official first action.

Countercurrent immunoelectrophoresis in the diagnosis of viral infections of the central nervous system

Countercurrent immunoelectrophoresis was utilized in the study of 621 specimens of cerebrospinal fluid to determine the correlation of detection of viral antigens with the clinical diagnosis of aseptic meningitis and related viral infections. A panel of viral antisera was immunoelectrophoresed against 119 specimens from patients with suspected viral infections of the central nervous system (group I), 32 from patients with bacterial meningitis (group 2), and 470 from patients with no suspected infection of the nervous system (group 3). One or more precipitin bands were detected in 79% of specimens from group 1, 19% from group 2, and 4% from group 3. Paired acute- and convalescent-phase sera from 32 (78%) of 41 patients with precipitin bands detected by countercurrent immunoelectrophoresis demonstrated a fourfold or greater change in complement-fixing antibodies to the detected antigen. With refinements in antisera, countercurrent immunoelectrophoresis may become useful in the rapid laboratory diagnosis of viral infection of the central nervous system.

Involvement of the sympathetic nervous system in the urinary bladder internal sphincter and in penile erection in the anesthetized cat

Male cats were anesthetized with pentobarbital. In one series of experiments a Foley catheter was placed suprapubically in the urinary bladder and physiologic saline, under a constant head of pressure, was allowed to flow at a constant rate through the bladder. Alpha-adrenergic stimulants such as ephedrine, norepinephrine, or methoxamine all caused a decrease or cessation in urinary flow. This effect was reversed by the alpha-adrenergic blocking agent, phentolamine. In addition, phentolamine administration caused penile erection. Erection also occurred after administration of the alpha-adrenergic blocking agent, phenoxybenzamine, or the beta2-adrenergic stimulants terbutaline or salbutamol. In each case the erection could be reversed, and usually terminated completely, by administration of the beta-adrenergic blocking agent, propranolol. Hypotension per se was not the required event to initiate erection because administration of acetylcholine, histamine, or prostaglandin E2 did not result in penile erection. In two of five experiments nitroprusside caused an erection. It was concluded that a predominance of beta2 activity in the penile vasculature is involved in erection.

Tubular Flow Reactors With First-Order Kinetics

A method is presented for automatically calculating true first order rate constants for gas phase and wall reactions from experimentally observed decay parameters in tubular flow reactors. It includes the effects of axial and radial diffusion and Poiseuille flow.

Treatment of Dupuytren's contracture. Long-term results after fasciotomy and fascial excision

Of 359 hands treated surgically for Dupuytren's contracture, 135 were available for study after two years or more, often because of recurrence. Of the sixty-five hands treated by excision of the involved fascia (subtotal fasciectomy), 63 per cent had recurrences in the area operated on but only 15 per cent had sufficient deformity to warrant another operation. Of the forty-one hands treated by palmar fasciotomy, 43 per cent had recurrent deformities severe enough to warrant further surgical treatment. After palmar fasciotomy, improvement at the metacarpohalangeal joint persisted; but, as expected, the deformity at the proximal interphalangeal joint progressed just as it did in an untreated control group. The average postoperative period of disability was fifty-nine days after fasciectomy and twenty-one days after fasciotomy. Stiffness and hematoma occurred after fasciectomy but were not observed after fasciotomy. A digital nerve was severed during one fasciotomy and one fasciectomy. Excision of the involved fascia, therefore, gave the best long-term results but was associated with a higher incidence of postoperative complications.

The possible role of histones in the mechanism of chromosomal G banding

Cytochemical data are presented to show that the histone fractions f1 and f2a are involved in the induction of chromosomal G bands, whereas the f2b and f3 fractions are not involved. Removal of the f1 and f2a fractions probably occurs during fixation and is necessary for the induction of G bands.

Stabilizing effect of inorganic phosphate salts on antibiotic-steroid ophthalmic preparations

Drocinonide phosphate potassium forms an insoluble complex with neomycin sulfate in aqueous solution. Dibasic sodium phosphate can be employed in an ophthalmic formulation to prevent the formation of this precipitate without affecting the stability of the steroid or the bioactivity of the antibiotic. Other phosphate steroid salts behaved in a like manner.

Ammonia and urea transport by the excluded human colon

1. Ammonia and urea transport across the colonic mucosa was studied by a perfusion technique in four subjects with colonic exclusion for chronic hepatic encephalopathy. 2. Reduction of luminal pH inhibited net and unidirectional transport of ammonia from lumen to plasma, but net absorption from high luminal concentrations persisted at low pH. 3. Neither addition of urea to the perfusate nor intravenous infusion of urea produced a consistent increase in the colonic excretion of ammonia when ammonia-free solutions were perfused. 4. In one subject intravenous infusion of (15N)-ammonium chloride produced rapid labelling of colonic effluent ammonia and within 60 min the specific enrichments of ammonia in effluent and in arterial plasma were approximately equal. 5. During perfusion of nitrogen-free solutions, only small amounts of urea appeared in the effluent, suggesing limited permeability of the colonic mucosa to urea. 6. These results are discussed in relation to the equilibration of ammonia across the colonic mucosa by both ionic and non-ionic diffusion. The lack of evidence of 'juxtamucosal' (as opposed to luminal) ureolysis is in contrast to other observations on the intact colon. The possible reasons for and implications of this discrepancy are discussed.