Purification of heat-labile enterotoxin from an enterotoxin from an enterotoxigenic Escherichia coli of human origin by monoclonal immunoaffinity chromatography

Heat-labile enterotoxin (LT) was purified from an enterotoxigenic Escherichia coli 015H11 of human origin. The purification steps included French pressure cell disruption of the bacteria, salting-out, DEAE-Sephacel on chromatography. Application of this procedure resulted in a 95.1-fold purification of LT with a yield of 19.9% as determined by rabbit ileal loop assay. The final LT preparation showed only one protein-staining band on polyacrylamide gel electrophoresis, indicating that the purified LT was homogeneous.

Gamma-aminobutyric acid- and picrotoxin-induced changes in c-wave and light peak of retinal potentials in the chick

Retinal potentials were recorded from the eyes of anesthetized and immobilized chicks by a standard direct current method. The amplitude of the electroretinogram (ERG) c-wave was measured 2 and 5 sec after the onset of the light stimulus, as indexes of the fast-rise c-wave (cF-wave) and the slow-rise c-wave (cS-wave), respectively. An intravitreal injection of gamma-aminobutyric acid (GABA) at an estimated intravitreal concentration of 10(-9)-10(-7) M resulted in an increase of the amplitude of the cS-wave, a less remarkable change in the a- and cF-waves, and a slight decrease in the b-wave. The light peak of the retinal standing potential increased in amplitude following GABA administration (10(-7)-10(-4) M). Following an intravitreal injection of picrotoxin (10(-5)-10(-3) M), the polarity of the cS-wave changed from positive to negative and a significant decrease and deformation in the light peak was observed. The amplitude of the a-wave, however, increased in the range of the higher dose, while that of the b- and cF-waves decreased markedly but no polarity reversal of the cF-wave was found. The results may suggest that the GABA-ergic synapse plays a significant role in production of the cS-wave and the light peak, along with that of the pigment epithelium.

Synthesis of 3-(3-pyridyl)- and 3-(3-benzo[b]thienyl)-D-alanine

The DL-arylamino acid ethyl ester derivatives of beta-(3-pyridyl)-DL-alanine, and beta-(3-benzo[b]thienyl)-DL-alanine were synthesized by diethyl acetamidomalonate condensation with the respective arylmethyl halides followed by partial hydrolysis to the monoethyl ester and decarboxylation. Each derivative was enzymatically resolved to a separable mixture of the corresponding N-acetyl-L-amino acid and the unchanged D amino acid derivative. Acidic hydrolysis of the latter gave the corresponding D-amino acid, the optical purity of which was established by HPLC analysis of the 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate (GITC) derivative. The free D amino acids were converted to D-BOC derivatives by reaction with di-tert-butyldicarbonate in tert-butyl alcohol, water and sodium hydroxide.

Pharmacokinetics and metabolism of an intravenously administered penem (Sch 34343) in humans

The pharmacokinetics of Sch 34343, a new broad-spectrum penem antibiotic, was studied in subjects receiving 1 g of 14C-labeled drug by intravenous administration. At the end of a 30-min intravenous infusion, the mean maximum concentration of drug in serum was 39 micrograms/ml for unchanged Sch 34343 and 49 mu eq/ml for total radioactivity. The mean serum half-lives of Sch 34343 were 0.16 h for the distribution phase and 0.80 h for the elimination phase. The total body clearance of Sch 34343 was 7.52 ml/min per kg, and the mean apparent volume of distribution was 525 ml/kg. Over a 4-day period, mean urinary excretion of radioactivity accounted for 87.9% of the dose, and mean urinary excretion of unchanged Sch 34343 accounted for 23.6% of the dose. The total radioactivity in feces on days 0 to 6 accounted for only 0.8% of the dose. In serum from 0.5 and 1 h, unchanged Sch 34343 represented the major radioactive peak, with negligible amounts of several metabolites. In urine, there were at least six metabolites in addition to Sch 34343. The amount of unchanged Sch 34343 accounted for 33% of radioactivity in samples of urine from 0 to 2 h, 22% in urine from 2 to 4 h, 15% in urine from 4 to 8 h, and 0% in urine from 8 to 12 h.

Effect of dopamine and haloperidol on the c-wave and light peak of light-induced retinal responses in chick eye

The relation between dopaminergic cells (and centrifugal fibers), the electroretinogram (ERG) c-wave, and the light peak were electrophysiologically investigated by observing the effects of a retrobulbar conduction block and intravitreal injection of either dopamine or haloperidol on these retinal responses. The retrobulbar conduction block (1% lidocaine) caused a decrease in the amplitude of the c-wave and the light peak in newly hatched chicks. Injections (2-20 microliters) containing dopamine (0.1-10 mM) or haloperidol (1.3-13 mM) were given intravitreously while the responses were recorded. Although intravitreous injection of saline for control resulted in no observable change in the responses, dopamine selectively augmented the c-wave of ERGs and the light peak, but not the a-, b-, and d-waves. Haloperidol decreased first the light peak and later the c-wave. The augmentation of the retinal responses by dopamine and their reduction by haloperidol was statistically significant. The estimated threshold concentration of dopamine in the vitreous cavity was 1-3.5 microM. Since in many species the interplexiform cells have been found to contain dopamine, we hypothesize that the modulatory effects on the c-wave and the light peak in this preparation may be due to a centrifugal feed-back loop which includes the interplexiform cells to the horizontal and bipolar cells and the horizontal cells to the cones.

Development and use of a radioimmunoassay for D-(-)-norgestrel 17 beta-cyclopentanecarboxylate

The synthesis of the 6 alpha-carboxymethylmercapto BSA and homologous histamine conjugate of D-(-)-norgestrel 17 beta-cyclopentanecarboxylate is reported. Using the BSA conjugate as an immunogen for the development of antibody in the rabbit and the 125I-histamine conjugate as the radioligand, a radioimmunoassay (RIA) for the ester was developed. Serum profiles of the free alcohol and ester were determined following IV or IM injection in macaques. Peak values for the ester (about 12 ng/mL) were observed 2 min following an IV bolus of 0.5 mg in one rhesus monkey. Blood levels dropped rapidly within the first 30 min and were barely detectable at 24 h. Serum levels of the free alcohol rose to a peak at 30 min and then declined slowly to very low values by 24 h. Following IM injection of 20 mg in cynomolgus monkeys, peak levels of the ester were observed within a few days while the free alcohol reached a maximum about day 30. Serum concentrations of D-(-)-norgestrel had fallen to about 0.4 ng/mL 160 days post-injection when levels of the ester fell below 0.2 ng/mL.

Pharmacokinetics and metabolism of [14C]rosaramicin in dogs

The pharmacokinetics and metabolism of [14C]rosaramicin were studied in dogs after intravenous (i.v.; 10 mg/kg [bodyweight]) and oral (25 mg/kg) administration. After i.v. administration, rosaramicin levels in plasma declined rapidly, with half-lives of 0.22 h for the distribution phase and 0.97 h for the elimination phase. The apparent volume of distribution was 3.43 liters/kg, and the total body clearance was 106 mg/min . kg, indicating extensive distribution in tissue or metabolism or both. The absorption of oral solution was 58%, and the absolute bioavailability of rosaramicin was 35%. The plasma area under the curve of unchanged rosaramicin was only 5% that of total radioactivity after oral administration and 8% after i.v. administration, indicating extensive metabolism of the drug. The total radioactivity excreted in urine accounted for only 24% of the i.v. dose and 17% of the oral dose. Fecal radioactivity accounted for 71% of the i.v. dose and 68% of the oral dose. Several metabolites were observed in the plasma and urine. The amount of unchanged rosaramicin in urine (1 to 2% of the dose) was quite small after drug administration by either route.

Pharmacokinetic and therapeutic trial of sultamicillin in acute sinusitis

Sultamicillin, an antibiotic combining ampicillin and the beta-lactamase inhibitor sulbactam, was administered to 13 patients diagnosed as having acute sinusitis. Specimens from sinus were obtained for all 13 patients by transantral puncture. Pharmacokinetics, bacteriology, and therapeutic efficacy were assessed. Eighty-five percent (11 of 13) were cured; two treatment failures were subsequently shown to have chronic (rather than acute) sinusitis during surgical exploration. Diarrhea was frequently encountered, and Clostridium difficile-associated enteritis was documented for one patient. Beta-lactamase-producing organisms were not encountered in this study; however, this study provides impetus for further controlled clinical trials.

Characteristics of VA/Q distributions recovered from inert gas elimination data

The resolving powers of the enforced smoothing and log-normal parametric estimation techniques in recovering ventilation/perfusion ratio (VA/Q) distributions were evaluated using noisy inert gas elimination data simulated from hypothetical distribution functions representing various degrees of heterogeneity. The resolving powers were assessed in terms of the statistical recoverabilities of the shunt, dead space, modality, and modal moments characterizing the perfusion distribution. For all distributions tested, both modal mean and shunt were estimated by either technique with sufficient accuracies. Modal dispersions (sigma) were consistently overestimated by up to 0.15 decade for narrow distributions, but the mean errors became negligible for sigma greater than 0.2 decade. As compared with the shunt, the dead space estimates were more variable and biased, probably due to their indirect estimation from the perfusion distribution, which was imperfectly recovered. Both broad unimodal and widely separated bimodal or trimodal distributions (sigma greater than 0.6 decade) were recovered as bimodal distributions of similar forms, so that detection of modality was difficult. The recoveries by both techniques were comparable in most cases studied, except that parametric estimation generally tended to be more sensitive to measurement errors and was computationally less efficient. These results provide a useful basis for the interpretation of VA/Q distributions obtained from empirical inert gas data.

Steady-state bioavailability of dexbrompheniramine and pseudoephedrine from a repeat-action combination tablet

The steady-state bioavailabilities of dexbrompheniramine and pseudoephedrine were evaluated following multiple-dose administrations of a repeat-action combination tablet containing 6 mg of dexbrompheniramine maleate with 120 mg of pseudoephedrine sulfate every 12 h for 7 d compared with reference standards. The reference standards used in this study were concomitant administration of conventional 2-mg dexbrompheniramine maleate tablets every 4 h and 120-mg pseudoephedrine sulfate repeat-action tablets every 12 h, each for 7 d. Twelve healthy adult male volunteers completed this randomized two-way crossover study. Blood samples for subsequent assay were obtained at frequent time intervals throughout each 7-d dosing phase. Sensitive and specific gas-liquid chromatographic methods were used for the determination of dexbrompheniramine and pseudoephedrine in plasma. Based on the plasma levels, the times to reach steady state were determined. In addition, the major bioavailability parameters (Cmin, Cmax, tmax, and AUC) for days 6 and 7 of dosing were determined and statistically evaluated. The results of this study demonstrate that, at steady state, the repeat-action combination tablet and concomitant administration of the reference standards are bioequivalent.

Pharmacokinetics and metabolism of rosaramicin in humans

The pharmacokinetics of rosaramicin was studied in subjects receiving 500 mg of the drug (i) by 1-h intravenous infusion, (ii) in solution orally, or (iii) as tablets orally. After intravenous administration, the rosaramicin levels in serum declined rapidly with t1/2S of 0.27 h for the distribution phase and 3.28 h for the elimination phase. The apparent volume of distribution was 3.78 liter/kg, and the total body clearance was 13.41 ml/min per kg, indicating extensive tissue distribution or metabolism or both. Similar pharmacokinetic data were obtained after oral administration of the drug in solution or tablets and after intravenous dosing. The absolute bioavailability of the drug administered orally, in either tablets or solution, was 32 to 39%. The metabolism and excretion of [14C]rosaramicin administered orally were also evaluated in volunteers. The serum area under the curve (infinity) of unchanged rosaramicin was 19% of that of total radioactivity, indicating extensive metabolism of the drug. About 7.0% of the radioactivity was recovered in the urine, and 86.7% was recovered in the feces. Only a small amount of unchanged rosaramicin was present in the urine (7 to 9% of urinary radioactivity), but none was present in the feces. The major metabolite, 20-bis-ureidorosaramicin, represented 17 to 38% of the radioactivity in the urine and 26 to 29% of the radioactivity in the feces.

7 alpha-Methylnorethindrone enanthate 10 beta-hydroperoxide: isolation and characterization

10 beta-Hydroperoxy-7 alpha-methylnorethindrone 17-heptanoate (II), a product of allylic autoxidation of 7 alpha-methylnorethindrone enanthate (I), has been isolated and characterized. The synthesis of the hydroperoxide (II) from the 3-ethylene ketal of 7 alpha-methylnorethynodrel (III) was achieved. Esterification of alcohol (III), subsequent deketalization, and photochemical oxygenation resulted in the hydroperoxide (II). Reduction of the hydroperoxide (II) to the 10 beta-alcohol (VI) and acetylation of (II) to the 10 beta-acetoxyperoxide (VII) are described. A single subcutaneous injection of the compounds (II), (VI), and (VII) to rats failed to produce long term inhibition of fertility in contrast to the parent compound (I) which is at least five times more effective than norethindrone enanthate as measured by suppression of vaginal cornification and estrous cycles.

Treatment of ampicillin-resistant acute otitis media in the chinchilla

The efficacy of sulbactam sodium (CP45,899-2) was investigated using the chinchilla animal model of acute otitis media with effusion (AOME). Both ears of 78 chinchillas were inoculated with beta-lactamase-producing nontypable Hemophilus influenzae. Half of the animals were treated with ampicillin sodium alone (group A) and the remaining animals received ampicillin plus sulbactam (group B). On day 14, all of the ears in group B were culture-negative whereas H influenzae was recoverable in over 70% of the effusions in group A. Similarly, the course of middle ear effusion was significantly abbreviated in group B during the two-week study period. These findings suggest that sulbactam in combination with ampicillin is effective in treating AOME secondary to infection with beta-lactamase-producing nontypable H influenzae in the chinchilla animal model.

Influence of type of carbohydrate on atherosclerosis in baboons fed semipurified diets plus 0.1% cholesterol

Five groups of six (three male, three female) baboons (Papio ursinus) were maintained for 17 months on a semipurified diet containing 40% carbohydrate, 25% casein, 13.9% coconut oil, 0.1% cholesterol, 15% cellulose, 5% salt mix (USP XIV) and 1% vitamin mix. The carbohydrates fed were: fructose, sucrose, starch, glucose, and lactose. A fifth group was used as control and was fed bread, fruit, and vegetables. Serum, liver, and tissue lipids were analyzed at the end of the feeding period as were cholesterol absorption (as 3H-cholesterol) and synthesis (from 14C-mevalonic acid). Serum cholesterol and beta-lipoprotein levels were elevated in all the test groups compared to final control levels or to starting levels for all the baboons. Average serum cholesterol levels of the test groups were not significantly different. Liver lipids were elevated in all test groups except that fed glucose. Baboons on the test diets absorbed more exogenous cholesterol (3H) but biosynthesis of this sterol was not inhibited. The ratio of biliary primary/secondary bile acids was below normal levels only in the animals fed fructose and sucrose. Cholesteryl ester fatty acid spectra of serum and liver reflected the dietary fat. Fecal weight was 69% higher in lactose fed animals and 31% lower in sucrose fed animals than in the controls. The ratio of endogenous or exogenous neutral/acid steroids was considerably lower in the fructose-fed baboons than in the other animals. On this diet average aortic sudanophilia (percentage of surface) was: fructose, 11.3; sucrose, 10.4; starch, 21.3; glucose, 17.2 lactose, 65.8; and control, 1.4. Gross atheromatous lesions were seen in five of six baboons fed lactose; three of six baboons fed fructose; two of six baboons fed sucrose, and one of six baboons fed starch. In a second experiment three groups of baboons were fed the control diet, the semipurified diet in which the carbohydrate was lactose, and the semipurified diet containing lactose plus 0.1% cholesterol for 8.5 months. Serum lipids were elevated in the two test groups but liver lipids were not significantly different from control levels. Average aortic sudanophilia (percentage of area) was: lactose, 2.2; lactose-cholesterol, 20.8; and control, 0.3%. One of the six baboons in the lactose-cholesterol group had visible atherosclerotic lesions. These experiments represent the first successful attempt to produce severe atherosclerosis in baboons by dietary means alone.

Nitrones. 7. alpha-Quinoxalinyl-N-substituted nitrone 1,4-dioxides

A series of alpha-quinoxalinyl-N-substitute nitrone 1,4-dioxides has been synthesize and evaluated as antibacterial and antiprotozoal agents. Structure-activity relationships are discussed. Of the compounds tested, alpha-(3-methyl-2-quinoxalinyl)-N-methylnitrone 1,4-dioxide (2) was the most active agent in vivo against the gram-negative and the gram-positive organisms.

Dietary essential fatty acids in cystic fibrosis

Analyses of serum lipids of children with cystic fibrosis (CF) have indicated a deficiency in essential fatty acids (EFA). In view of a report that intravenous administration of soybean oil emulsions normalized sweat sodium values in CF children, we studied the effects of orally administered essential fatty acids (as corn oil) for one year. Some improvement was noted in all patients, but no one consistent factor predominated. However, arachidonic acid, which was found only in trace amounts or was absent in sera of all children with CF before the clinical trial, was increased significantly in the sera after the oral administration of EFA for one year. Other findings included a significant decrease in sweat sodium and T3 in most patients.

Quantitative recovery of lipids from aortas stained with sudan IV

The separation of Sudan IV from lipid extracts of stained aortas can be accomplished by thin layer or column chromatography, but the most convenient method involves adsorption of the dye to activated carbon. The aortic lipids are thus recovered quantitatively.

Evaluation of topical polyinosinic acid-polycytidylic acid in treatment of localized herpes zoster in children with cancer: a randomized, double-blind controlled study

Twenty-four children with cancer and localized herpes zoster were randomized to receive either topical polyinosinic acid-polycytidylic acid [poly(I:C)] or a saline placebo. Solutions containing 1.0 or 2.5 mg of drug per ml were applied to the lesions every 3 h, seven times a day for 7 consecutive days. Serial, standardized color photographs were used to evaluate the progression of lesions and maximum percentage of dermatome involvement. In patients receiving poly(I:C), the median days of new lesions after therapy was 2.0 days as opposed to 3.5 days in placebo-treated patients. This difference was not statistically significant. Moreover, the total median days of lesions and percentage of dermatome involvement were similar in both groups, as were complications. Neither the concentration nor the total dose of drug was related to the outcome of infection. We conclude that topical poly(I:C), as used in this study, was of no benefit in treatment of localized herpes zoster.