Characterization of D-2 dopamine receptors in a tumor of the rat anterior pituitary gland

Dopamine receptors in the 7315a transplantable rat anterior pituitary tumor were characterized using radioligand binding assays with [3H]spiroperidol ([3H]SPD) and assays of adenylate cyclase activity. Scatchard analysis of the binding of [3H]SPD yielded linear plots and a Kd value of 73 pM. Studies of the inhibition of the binding of [3H]SPD were performed with a series of competing ligands, including the antagonists domperidone, (+)-butaclamol and sulpiride and the agonists dopamine, bromocriptine and N-propylnorapomorphine. Inhibition curves for the antagonists gave Hill coefficients of approximately 1, consistent with the presence of only a single class of binding sites with a high affinity for [3H]SPD. In contrast, the Hill coefficient for dopamine was significantly less than 1. When assays were carried out in the presence of 300 microM GTP, the inhibition curve for dopamine was shifted to the right and the Hill coefficient increased to approximately 1. An effect of GTP on the affinity of a receptor for agonists is consistent with the existence of at least two agonist affinity states. Inhibition of the binding of [3H]SPD by the partial agonist bromocriptine was not affected when assays were carried out in the presence of GTP. The uniform low affinity of the selective serotonin antagonist ketanserin for these sites indicated that the radioligand was not labeling serotonin-2 receptors in this tissue. A good correlation was observed between the Ki values for competing ligands measured in the tumor and in homogenates of rat striatal tissue. Dopamine was shown to inhibit forskolin-stimulated adenylate cyclase activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of (+)-cyclaradine-5'-esters as prodrugs for (+)-cyclaradine in animals

Both (+)-cyclaradine-5'-methoxyacetate (CM) and (+)-cyclaradine-5'-ethoxypropionate (CE) were converted to (+)-cyclaradine (C) in squirrel monkey and human sera at 37 degrees C. CE was more stable than CM. After oral administration (20 mg base equivalent per kg) of either CM or CE, no unchanged esters were observed in serum of squirrel monkeys, rabbits, or rats. Instead, C was detected, indicating conversions of CM and CE to C in vivo. In squirrel monkeys, the areas under the curve (AUCs) of C obtained from oral dosing with CM were 61% higher than those obtained from dosing with C, indicating that CM may be a good prodrug for C. In squirrel monkeys, rabbits, and rats, CE resulted in a 20 to 90% higher AUC of C than did CM, indicating that CE was better absorbed than CM.

Activity of (+)-cyclaradine (Sch 31172) against herpes simplex virus in vitro and in vivo

(+)-Cyclaradine (Sch 31172) is the carbocyclic derivative of adenosine arabinoside (9-beta-D-arabinofuranosyladenine). Because it is not deaminated by deaminase in serum, as is adenosine arabinoside, (+)-cyclaradine is about 2 to 5 times more active in vitro against herpes simplex virus. (+)-Cyclaradine has in vitro activity nearly equivalent to that of phosphonoformate but is significantly less active than acycloguanosine (acyclovir; ACV), trifluorothymidine, or 9-(1,3-dihydroxy-2-propoxymethyl)guanine. The absolute ratios of in vitro activities are difficult to determine because of variability among virus strains, inoculum size, and dependence on the tissue culture cell line in which the comparative test is carried out. (+)-Cyclaradine is active against TK-, ACV-resistant mutants. In the guinea pig model of vaginal herpes simplex virus infection, (+)-cyclaradine is only slightly less active than ACV when both molecules are nearly equivalently bioavailable; thus, the large difference in activity seen in vitro is not reflected in this in vivo model system.

[Comparison of in vitro assays for the cytotoxic effect of anticancer drugs]

The cytotoxic effects of three anticancer drugs, methotrexate (MTX), 5-fluorouracil (5-Fu) and oridonin (Rub A), were investigated using a human gastric adenocarcinoma cell line (MGc80-3) and a human esophageal cancer cell line (CaEs-17) by means of colony-forming assay, dye exclusion test, measurement of incorporation of 3H-thymidine into DNA and examination of mitotic index. MGc80-3 cells, exposed for 24 hr to increasing concentrations of MTX (0-1.6 micrograms/ml), 5-Fu (0-12 micrograms/ml) or Rub A (0-25 micrograms/ml), showed different types of dose-survival curves determined by colony-forming assay. It suggests that these drugs have different models of action. The killing effect of MTX and 5-Fu was obviously underestimated by dye exclusion; the cell numbers were reduced to about 30% and 60% of control, while the colony formation showed approximately 2.5 and 3.5-log kill. When CaEs-17 cells exposed for 6 hr to varying concentrations of Rub A (0-15 micrograms/ml), the reduction in cell number (15 micrograms/ml, T/C = 18.0%) was always less than that (15 micrograms/ml, T/C = 3.8%) in colony formation. Under the same condition, the mitotic index, however, increased with increasing dosage first, and then the T/C values, at higher concentrations (5-15 micrograms/ml), reached approximately 200%. Although the drug significantly inhibited the incorporation of 3H-thymidine, the pattern of the dose-response curve differed from the dose-survival curve. These findings in cytobiochemistry and morphology may contribute to explain the cytotoxicity of an anticancer drug, but failed in correlation with the data obtained by colony-forming assay which seems to be the most reliable method for determining drug-induced cell lethality.

Relationship between production of epidermal growth factor receptors, gene amplification, and chromosome 7 translocation in variant A431 cells

Synthesis of the epidermal growth factor (EGF) receptor has been analyzed in a series of variant A431 human epidermoid carcinoma cell clones reported to contain different amounts of EGF binding sites. The amount of EGF receptor protein, quantitated by immunoaffinity chromatography, and EGF receptor mRNA, quantitated by cDNA hybridization, were closely correlated to the extent of EGF receptor gene amplification. This correlation existed in variants selected for reduced EGF receptors and in revertants from those variants with increased EGF receptors. There was also a correlation between the frequency of translocation of chromosome 7, containing the EGF receptor gene, and EGF receptor protein. These results support gene amplification as the mechanism enhancing A431 cell EGF receptor protein and determining growth responses.

Pharmacokinetics of Sch 34343 in rats and dogs

The pharmacokinetics of 14C-Sch 34343 were studied in rats and dogs following intravenous and intramuscular dosing. In both species, it was rapidly absorbed after intramuscular dosing. The serum AUC for total radioactivity and for intact drug after intramuscular dosing were similar to those obtained after intravenous dosing. Following both routes of drug administration, the elimination of half-life (T 1/2 beta) was 7 min in rats and 25-32 min in dogs. Following intravenous dosing of 14C-Sch 34343 to rats, radioactivity in tissues disappeared rapidly with time indicating no tissue accumulation. Highest concentrations of radioactivity were seen in the kidney. Liver, lung, skin and heart appeared to have concentrations of radioactivity similar to those of blood. Sch 34343 was excreted rapidly and primarily into the urine in both rats and dogs. After either route of dosing, urinary excretion of total radioactivity ranged from 84 to 93% and that of intact Sch 34343 from 41 to 51% of the dose, respectively. In addition, the effect of pretreatment with probenecid on the pharmacokinetics in rats and dogs and in anephric rats were also evaluated. Pretreatment with probenecid prolonged the elimination half-life in both rats and dogs. Anephric rats had a longer half-life than normal rats.

The excretion of rosaramicin in breast milk

The excretion of rosaramicin, a macrolide antibiotic, was studied in the breast milk of ten lactating women. Breast milk and serum samples were collected for 48 hours after a single 250-mg oral dose of rosaramicin. Mean serum half-life, apparent volume of distribution, and oral clearance were 4.4 hours, 3.41 L/kg, and 6.34 mL/min/kg, respectively. Mean milk/serum ratio was 0.12 and the total amount of drug recovered over the first ten hours was 6.25 micrograms, approximately 0.0025% of the dose. A positive correlation between breast milk volume and breast milk clearance was found, suggesting that the amount of drug received by a nursing infant will depend on the volume of milk produced by the mother. Drug-induced toxicity from the parent drug is unlikely to occur in nursing infants since the amount of rosaramicin that a nursing infant could ingest is small.

Comparative pharmacokinetics of Sch 28191 and amphotericin B in mice, rats, dogs, and cynomolgus monkeys

The pharmacokinetics of Sch 28191, the N-D-ornithyl methyl ester of amphotericin B, and amphotericin B were studied in mice, rats, dogs, and cynomolgus monkeys after an intravenous dose of 0.6 mg/kg was administered. The decline in the concentrations of Sch 28191 and amphotericin B in serum appeared to be biphasic in nature. The half-life at the distribution phase and the half-life at the elimination phase of Sch 28191 were similar to those of amphotericin B in all animals studied. The half-life at the distribution phase in serum was 0.9 to 1.5 h in all animals studied. The half-lives at the elimination phase in serum were 25 to 28 h in mice, 16 to 18 h in rats, 44 to 47 h in dogs, and 35 h in cynomolgus monkeys. The areas under the serum concentration-time curves of Sch 28191 were five- to eightfold larger than those of amphotericin B in rats, dogs, and cynomolgus monkeys but were only slightly larger than those of amphotericin B in mice. In dogs, the urinary excretion (over 9 days) of unchanged drug accounted for 23% of the Sch 28191 dose and 25% of the amphotericin B dose. The concentrations of Sch 28191 in serum were also studied after the intravenous administration of 0.3, 0.6, or 1.25 mg/kg to dogs. The serum concentration-time curves were parallel for these doses. There was a linear relationship between the areas under the concentration-time curves and the doses, indicating dose proportionality.

Matched filters for bin picking

Currently, a major difficulty for the widespread use of robots in assembly and material handling comes from the necessity of feeding accurately positioned workpieces to robots. ``Bin picking'' techniques help reduce this constraint. This paper presents the application of matched filters for enabling robots with vision to acquire workpieces randomly stored in bins. This approach complements heuristic methods already reported. The concept of matched filter is an old one. Here, however, it is redefined to take into account robot end-effector features, in terms of geometry and mechanics. In particular, the proposed filters match local workpiece structures where the robot end-effector is likely to grasp successfully and hold workpieces. The local nature of the holdsites is very important as computation costs are shown to vary with the fifth power of structure size. In addition, the proposed filters tend to have a narrow angular bandwidth. An example, which features a parallel-jaw hand is developed in detail, using both statistical and Fourier models. Both approaches concur in requiring a very small number of filters (typically four), even if a good orientation accuracy is expected (two degrees). Success rates of about 90 percent in three or fewer attempts have been experimentally obtained on a system which includes a small minicomputer, a 128 × 128 pixel solidstate camera, a prototype Cartesian robot, and a ``universal'' parallel-jaw hand.

Continuously tunable multiple-order stimulated four-photon mixing in a multimode silica fiber

Stimulated four-photon mixing (SFPM) has been observed up to four orders in a 300-m-long, low-loss, large-core multimode silica fiber pumped by a dual-frequency dye laser. The phase-matching condition for SFPM was uncritically achieved in the multimode fiber, so that, by varying the frequency separation of the two laser lines, it was possible to tune continuously an intense line generated by SFPM under the Raman-gain curve in the range of 350 to 495 cm(-1).

High-pressure liquid chromatographic method for determination of Sch 28191 in biological fluids

A high-pressure liquid chromatographic method has been developed for the measurement of N-D-ornithyl amphotericin B methyl ester (Sch 28191) in biological fluid. The method involves protein precipitation with methanol, followed by separation of the supernatant on a reverse-phase column and quantitation by absorbance at 405 nm. This technique resulted in a recovery of 97%. There was a good linear relationship between the peak height ratio and Sch 28191 concentrations ranging from 0.015 to 20 micrograms/ml. In addition, this method was specific for Sch 28191 since all of its analogs tested did not interfere with the assay. The method was reproducible with a lower limit of quantitation of 0.015 microgram/ml. Serum levels obtained from this method were in good agreement with those obtained from a microbiological assay only when drug concentrations were higher than 1.5 microgram/ml. The high-pressure liquid chromatographic method is useful in monitoring serum and urine drug levels in animals and should prove to be useful for pharmacokinetic studies of the drug with therapeutic doses in humans.

Isolation and identification of a metabolite of rosaramicin in human urine

A urinary metabolite of rosaramicin in man was isolated and purified by a preparative HPLC method. On the basis of infrared, proton, and 13C magnetic resonance spectroscopic data, and elemental analysis, the metabolite has been identified as 20-bisureidorosaramicin. An authentic 20-bisureidorosaramicin was synthesized and shown to be identical to the urinary metabolite in infrared, 13C magnetic resonance spectral data and elemental analysis. In addition, fast atom bombardment mass spectral data of the metabolite was consistent with the structure of 20-bisureidorosaramicin. In mice receiving orally administered synthetic 20-bisureidorosaramicin, significant concentrations of rosaramicin were found in plasma, indicating the conversion of 20-bisureidorosaramicin to rosaramicin in this species.

A Mathematical Model for Split Point Drill Flanks

For consistent and accurate production of a split (crankshaft) point drill, proper mathematical models are derived. Modification of the existing, basic conical flank model yields the model for the major (primary) flank surface. An independent, planar model for splitting the point (secondary flank) is also derived. The models yield grinding parameters to set the relative positions of the drill and the grinding wheel for precise production of the split point geometry.

Quantitative explanation for increased affinity shown by mixtures of monoclonal antibodies: importance of a circular complex

Mixtures of some but not all monoclonal antibodies which bind to separate epitopes on human chorionic gonadotropin (hCG) show an increased affinity for the hormone. To find an explanation for the increase in affinity, we developed a mathematical model which predicts the quantities of intermediates formed when pairs of IgG1 mouse monoclonal antibodies having affinities of approximately 10(8) M-1 for hCG are mixed with the hormone. At low antibody concentrations (i.e. less than 1 nM or 0.15 micrograms/ml) analysis of possible antibody-hormone combinations, including linear and circular chains composed of less than 12 molecules of antibody and 12 molecules of hCG, suggests the increase in affinity is due to formation of a circular complex containing two molecules of antibody and two of hCG. Further, the model predicts that the circular complex will be the major species formed at antibody-antigen equivalence. This prediction is supported by experimental observations on the molecular weight of a new complex formed in the presence of hCG and the mixture of the monoclonal antibodies. In addition, based on experimental values of binding constants for individual antibodies to hCG, the model correctly quantifies the loss in complex observed in the presence of excess hCG antigen. At high antibody concentrations (i.e. greater than 10 nM or 1.5 micrograms/ml) the formation of linear chains of antibody hCG pairs becomes appreciable and contributes to the increase in apparent affinity of the mixture for hCG. These results suggest that the observed affinity of complex mixtures of antibody for antigens containing multiple epitopes calculated from Scatchard plots may not be related to the affinity or avidity of any of the antibody species for a given epitope.

[Enzyme activity in the subcellular fractions of the liver of rats following a flight on board the Kosmos-1129 biosatellite]

The activities of malate, isocitrate, and lactate dehydrogenases were measured in the liver mitochondrial and cytoplasmatic fractions of rats flown for 18.5 days onboard Cosmos-1129. The activities of the oxidative enzymes, malate and isocitrate dehydrogenases, in the mitochondrial fraction and those of the glycolytic enzyme, lactate dehydrogenase, in the cytoplasmatic fraction were found to decrease.

High-pressure liquid chromatographic method for determination of Sch 29482 in human serum

A high-pressure liquid chromatographic method was developed for quantitative determination in human serum of a new penem antibiotic known as Sch 29482 (5R,6S,8R-2-ethylthio-6(1-hydroxyethyl)penem-3-carboxylic acid). The method involves serum extraction at an acid pH with ether, followed by separation on a reverse-phase column and UV light detection at 254 nm. This technique produced a good linear relationship between the peak height ratio and the Sch 29482 concentration, which ranged from 0.09 to 35.64 micrograms/ml. In addition, this procedure proved to be quite specific for Sch 29482, since all beta-lactam antibiotics tested did not interfere with the assay. For high concentrations (greater than 0.5 micrograms/ml), the mean values obtained from the high-pressure liquid chromatographic method correlated very well (r = 0.997) with those obtained from a microbiological assay. This method is accurate and reproducible, with a sensitivity of about 0.09 micrograms per ml of serum. It is useful for monitoring serum drug levels in animals and humans and can also be used for drug pharmacokinetic studies in humans.

Comparative bioavailability of a microsize and ultramicrosize griseofulvin formulation in man

The bioavailability of 500 mg of a microsize formulation of griseofulvin has been compared to two new ultramicrosize griseofulvin formulations, two 165 mg tablets and a 330 mg tablet, in sixteen healthy, male, volunteers in a randomized crossover study design. Based on the griseofulvin plasma levels measured at specified times over a 48-hour period, the major bioavailability parameters (i.e., area under plasma concentration-time curve, maximum plasma concentration, and time to reach maximum plasma concentration) were determined and statistically evaluated. The results showed that one 330 mg ultramicrosize tablet is bioequivalent to two 165 mg ultramicrosize griseofulvin tablets and that either ultramicrosize griseofulvin dosage regimen is bioequivalent to 500 mg of the microsize griseofulvin formulation.

Comparative bioavailability of d-pseudoephedrine from a conventional d-pseudoephedrine sulfate tablet and from a repeat action tablet

The bioavailability of a single dose of d-pseudoephedrine sulfate administered to male volunteers in repeat action tablet form (60 mg d-pseudoephedrine sulfate in the coat and 60 mg d-pseudoephedrine sulfate in the core) was compared with the bioavailability of an equivalent quantity of the drug given as two 60 mg conventional tablets, one given at 0 hour and the second 6 hours later. There was no significant difference (P less than 0.10) between the conventional tablets and the repeat action tablet formulation in area under the plasma concentration-time curve and the maximum plasma concentration of d-pseudoephedrine. Based on the data, we conclude that the repeat action tablet formulation and the conventional tablet are bioequivalent.

Bioavailability of d-pseudoephedrine and azatadine from a repeat action tablet formulation

The objective of this study was to compare in man the bioavailability of d-pseudoephedrine and azatadine from a repeat action tablet formulation and from conventional tablets. The repeat action tablet, containing 1 mg of azatadine maleate in the coat, and 60 mg of d-pseudoephedrine sulfate in both the coat and the core, was given at 0 hour. A conventional tablet of 60 mg of d-pseudoephedrine sulfate was given at 0 and 4 hours and a conventional tablet of 1 mg of azatadine maleate was given at 0 hour. The plasma levels of d-pseudoephedrine were measured by gas-liquid chromatography and the amount of azatadine in the urine was determined by a mass fragmentographic procedure. The results showed that there were no statistically significant differences in the measured bioavailability parameters (area under plasma concentrations-time curve, maximum plasma concentration and time to reach maximum plasma concentration) for pseudoephedrine from repeat action tablets and conventional d-pseudoephedrine sulfate tablets; neither was there any statistically significant difference in the cumulative urinary excretion of azatadine from the repeat action tablets and conventional azatadine maleate tablets (p less than 0.10). These data clearly demonstrate the bioequivalence of the repeat action tablets and the conventional tablets of d-pseudoephedrine and azatadine.

Phase matching in the minimum-chromatic-dispersion region of single-mode fibers for stimulated four-photon mixing

We describe phase-matched stimulated four-photon mixing in single-mode fibers in the minimum-chromatic-dispersion region. Phase matching is achieved by using the refractive-index slope change and the guiding properties of the fundamental mode. Experimental results on large-shift (1600-cm(-1)) single-idler generation in single-mode fibers with 1.319-microm Nd:YAG laser pumping are presented.

Phase matching in birefringent fibers

We describe a new technique that utilizes birefringence for phase matching of stimulated parametric emission in a single-mode optical fiber. The frequency shift between the generated frequencies and the pump frequency can be controlled over a wide range (approximately 1000 cm(-1)) by the magnitude of birefringence built into the fiber.

Optical-pulse equalization of low-dispersion transmission in single-mode fibers in the 1.3 - 1.7-microm spectral region

We describe a simple optical-pulse-equalization technique for minimizing pulse dispersion in a single-mode fiber transmission system utilizing the positive- and the negative-dispersion characteristics of single-mode fibers on both sides of a zero-chromatic-dispersion wavelength.

High-pressure liquid chromatographic method for determination of rosaramicin in humans

A high-pressure liquid chromatographic method has been developed for the quantitative determination of rosaramicin in serum. This procedure involves addition of an internal standard, adjustment to alkaline pH, treatment with potassium carbonate, ether extraction, and a reverse-phase column separation with acetonitrile-acetate buffer mixture as the mobile phase. This technique produces a good linear relationship between the peak height ratio and the rosaramicin concentration. In addition, this method has proven to be quite specific for rosaramicin, since many of its derivatives tested do not interfere with the assay. The method is accurate and reproducible with a sensitivity of about 0.01 microgram of rosaramicin per ml of serum. It may be useful in monitoring drug levels in serum of patients and also for the pharmacokinetic studies of the drug in humans.

Direct demonstration of distortionless picosecond-pulse propagation in kilometer-length optical fibers

We describe the use of a mode-locked color-center laser to demonstrate nearly distortionless propagation of ~5-psec-wide, Fourier-transform-limited pulses, at or near the zero-dispersion wavelength, in two fused-silica, singlemode fibers of 0.76- and 2.5-km length, respectively. We also report the detection of sharply defined cross correlations between pulses directly from the laser and those had been delayed many microseconds by passage through a fiber.

Reduction of GTP activation of adenylate cyclase system by its coupling to hormone receptor

We have examined the characteristics of the adenylate cyclase system from control and butyrate-treated cells. Butyrate treatment results in both an increased number of catecholamine receptors and an induction of a response to the hormone, as reported previously (Tallman, J.F., Smith, C.C., and Henneberry, R.C. (1977) Proc. Natl. Acad. Sci. U.S.A. 74, 873-877); in addition, we found that the same treatment reduces the degree of activation of adenylate cyclase by GTP. We have demonstrated in two cell types that this decrease in GTP activation is inversely related to the degree of induction of the hormone response. Furthermore, in plasma membranes isolated from butyrate-treated cells, the hormone receptor is sensitive to GTP; i.e. GTP reduces the affinity of isoproterenol for the receptor. We propose that these changes reflect an interaction between the beta-adrenergic receptor and the nucleotide regulatory component and that this interaction represents, at least in part, the process of coupling. Several possible mechanisms which can account for the change in GTP activation are discussed in terms of our current understanding of the regulation of the adenylate cyclase system.

Absorption, metabolism, and excretion of 14C-tosifen in the dog and rat

14C-tosifen [N-2-(1-phenylpropyl)-N'-p-tolyl sulfonylurea] was readily absorbed in both rats and dogs. The rates of absorption, metabolism, and urinary excretion were higher in the rat than in the dog. More of the drug was excreted via the feces than in the urine of the rat, whereas in the dog, the drug was primarily excreted into the urine. The parent drug was the major radioactive component in the plasma of both species. In the urine, however, only a negligible amount of tosifen was found. The major urinary metabolite was a hydroxymethyl derivative which accounted for about 60% and 40% of the total radioactivity in the urine of the dog and rat, respectively.

Pulse delay measurements in the zero material dispersion wavelength region for optical fibers

Subnanosecond pulses in the 1120-1550-nm region are generated by multiple-order stimulated Raman scattering in a small core single-mode silica fiber pumped by a Q-switched and mode-locked Nd:YAG laser at 1064 nm. These near ir pulses are injected into various km long test fibers, and relative time delay changes between different wavelengths are used to determine dispersion in a region where fiber material dispersion is small. Zero material dispersion has been observed in germanium and boron-doped single-mode and multimode est fibers.

A cw tunable near-infrared (1.085-1.175-microm) Raman oscillator

This is the first report of a cw tunable Raman laser in the 1.1-microm region of the spectrum. A prism-tuned fiber Raman resonator with a 650-m-long, low-loss small-core single-mode silica fiber was pumped by a 5-W cw Nd:YAG laser at 1.064 microm. With two separate resonator mirrors for the first and the second Stokes oscillation, we have obtained first Stokes oscillation tunable from 1.085 to 1.13 microm and second Stokes oscillation tunable from 1.15 to 1.175 microm.

Isolation and identification of the major metabolite of albuterol in human urine

The major urinary metabolite of albuterol in man was isolated and purified by ion-exchange chromatography and countercurrent distribution. On the basis of proton magnetic resonance, infrared, and mass-spectral analysis, enzymic hydrolysis, and assay of inorganic sulfate after acid hydrolysis, the metabolite has been identified as the 4'-O-sulfate ester of albuterol.