Brown adipose tissue metabolism in ob/ob mice: effects of a high-fat diet and adrenalectomy

Adrenalectomy prevents development of obesity in ob/ob mice fed high-carbohydrate stock diets partly by stimulating the low thermogenic capacity of their brown adipose tissue (BAT). Adrenalectomy, however, fails to prevent development of obesity in ob/ob mice fed a high-fat diet. Effects of adrenalectomy on BAT metabolism in ob/ob mice fed a high-fat diet were thus examined. ob/ob mice fed the high-fat diet developed gross obesity despite normal BAT metabolism, as assessed by rates of norepinephrine turnover in BAT, GDP binding to BAT mitochondria, and GDP-inhibitable, chloride-induced mitochondrial swelling. Adrenalectomy failed to arrest the development of obesity or to influence BAT metabolism in ob/ob mice fed the high-fat diet. Development of obesity in ob/ob mice fed a high-fat diet is not associated with low thermogenic capacity of BAT or with adrenal secretions, as it is in ob/ob mice fed high-carbohydrate stock diets.

Clonogenic assay of gastric adenocarcinoma stem cells--clonogenic assay, stomach cancer

Clonogenic assay is the culturing of tumor stem cells, which are responsible for tumor growth by self renewal and differentiation to tumor end cells. Elimination of the malignant stem cells or their self renewal will lead cure of the tumor. Thus, the behavior of the stem cells by clonogenic assay has been correlated with prognosis and outcome of therapy.

We studied clonogenic assay by means of double agar system for 21 patients with advanced stomach cancer. The colony formation evaluted on 14th day of the culture was grown from 14 of 19 malignant effusions plated and 1 of 2 tumor nodules plated. The number of the colonies ranged from 5 to 96 per petri dish, and the median number was 20. The plating efficiency ranged from 0.001 to 0.036%, and the median was 0.003%. In the morphologic studies, the colonies made of tightly packed cells were grown from the poorly differentiated adenocarcinoma, whereas the colonies made of loosely packed cells with mucin formation were grown from the mucin secreting adenocarcinoma of stomach. The chemosensitivity in vitro tests to cisplatin were performed in 5 patients, and the results showed 4 sensitive and 1 resistant patient. The result of in vivo study with instillation of intraperitoneal cisplatin revealed that 3 patients “in vitro sensitive” were “responsive in vivo”, and 1 patient “in vitro resistant” was “non-responsive in vivo”.

We conclude that clonogenic assay of stomach cancer is useful method to understand the biology of the stem cell pool and select proper chemotherapy according to the chemosensitivity test.

Effects of adrenalectomy on energy balance in obese (ob/ob) mice fed high carbohydrate or high fat diets

We reported previously that adrenalectomy reduced the energy density of body weight gain (an indicator of proportional gain in lean and fat tissue) and the efficiency of energy retention in obese (ob/ob) mice to values approximating those in lean mice, but that adrenalectomy had much less influence on these parameters in ob/ob mice fed a purified high fat diet. To determine if fat was the exclusive factor in the purified high fat diet that negated effects of adrenalectomy, ob/ob mice were fed a purified high carbohydrate (glucose) diet identical in composition to the high fat diet, except for the fat/carbohydrate ratio. Responses of adrenalectomized ob/ob mice fed the purified high glucose diet from 4 to 7 wk of age mimicked those of mice fed the purified high fat diet, not those of mice fed the high carbohydrate nonpurified diet. Plasma glucose responses to a glucose load in adrenalectomized ob/ob mice paralleled the diet-dependent changes in energy balance. These results demonstrate that diet composition interacts with adrenal secretions to influence energy and glucose metabolism in ob/ob mice; consumption of either a purified high glucose or high fat diet negates the beneficial effects of adrenalectomy on energy and glucose metabolism observed when adrenalectomized ob/ob mice consume a nonpurified diet.

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.