Characteristics of β-endorphin-induced histamine release from rat serosal mast cells Comparison with neurotensin,dynorphin and compound 48/80

Summary Rat peritoneal mast cells were exposed to the neurohormone and basic opioid peptide content/n561712311808n24/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-endorphin. content/n561712311808n24/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-Endorphin induced a dose-dependent release of histamine from the mast cells. A significant histamine release was found at 5 content/n561712311808n24/xxlarge956.gif" alt="mgr" align="MIDDLE" BORDER="0">mol/l of content/n561712311808n24/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-endorphin and maximal release (35% of total) at 20 content/n561712311808n24/xxlarge956.gif" alt="mgr" align="MIDDLE" BORDER="0">mol/l. The histamine release process was very rapid and terminated within 30 s at 37°C, and in this sense is very similar to the histamine release induced by compound 48/80 or neurotensin. The histamine release was temperature-dependent showing an optimum release around 30°C, and it was independent of available extracellular calcium, but was inhibited in the presence of high extracellular calcium concentrations. Naloxone, only in very high concentrations (10 mmol/l), inhibited the release, and the very same concentration also inhibited the neurotensin — as well as the compound 48/80-induced histamine release. Cromoglycate and benzalkoniumchloride, a 48/80 antagonist, both produced a progressive dose-dependent inhibition of content/n561712311808n24/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-endorphin-, neurotensin- as well as compound 48/80-induced histamine release. Taken together, the findings indicate that the opioid peptide content/n561712311808n24/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-endorphin induces a selective, energy-dependent release of histamine from peritoneal rat mast cells. The pattern of release has much in common with that of compound 48/80 and other basic peptides, such as neurotensin and substance P. In addition this pattern of release is similar to that induced by dynorphin. Send offprint requests to Anita Sydbom at the above address     

The pharmacokinetics of doxifluridine and 5-fluorouracil after single intravenous infusions of doxifluridine to patients with colorectal cancer

Summary The disposition kinetics of a new 5-fluorouracil prodrug, 5content/k246108623462064/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-deoxy-5-fluorouridine (5content/k246108623462064/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">dFUR, doxifluridine), were investigated in six patients with colorectal carcinoma. Each patient randomly received two single intravenous doses of 5content/k246108623462064/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">dFUR (2 and 4 g · m^–2) on separate days.Plasma concentrations of 5content/k246108623462064/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">dFUR fell rapidly with terminal half-lives ranging from 16.1 to 27.7 min. A disproportionate increase in the area under the curve with increasing dose was seen in most patients. Doubling the dose resulted in a 40% decrease in nonrenal clearance (0.60 to 0.37 l · min^–1) but no apparent change in renal clearance (0.32 to 0.29 l · min^–1) or steady-state apparent volume of distribution (19.8 to 20.4 l).The mechanism for dose-dependence of 5content/k246108623462064/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">dFUR appears to be primarily due to nonlinear elimination associated with nonrenal processes rather than nonlinear plasma protein or tissue binding.     

Lymphocyte β-adrenergic receptor binding in panic disorder

Lymphocyte beta adrenergic receptor binding using [¹²⁵I]CNP was determined in patients with panic disorder (N=4) or agoraphobia with panic attacks (N=17) and age- and sex-matched healthy subjects (N=22). The patients showed a significantly lower number of content/wu4260l3781wn4j4/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-adrenergic receptor binding sites and a significantly higher affinity of binding than healthy subjects. A past or present history of major depression in the patients did not alter these findings. These results are consistent with a growing body of knowledge implicating noradrenergic dysfunction in the pathophysiology of panic anxiety.     

Synthesis,Physicochemical Properties,and Cytotoxicity of a Series of 5′-Ester Prodrugs of 5-Iodo-2′-deoxyuridine

Five aliphatic 5content/l6444461378u1m1u/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-esters of 5-iodo-2content/l6444461378u1m1u/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">deoxyuridine (IDU) were synthesized via an acid chloride alcoholysis reaction. The solubility in pH 7.4 phosphate buffer, lipophilicity as determined by partition experiments in octanol/pH 7.4 buffer, and cytotoxicity of these potential prodrugs were evaluated. The esters showed a 43- to 250-fold increase in lipophilicity and a 1.6- to 14-fold decrease in aqueous solubility relative to IDU. At a concentration of 50 µM, all esters showed reduced cytotoxicity toward uninfected Vero cells relative to IDU.     

A Biotin–Avidin-Based Enzyme Immunoassay for βh-Endorphin

An avidin–biotin enzyme-linked immunosorbent assay (ELISA) is described for content/h1v517777n768x1l/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">_h-endorphin (content/h1v517777n768x1l/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">_h-EP). Microtiter plates coated with commercially available antibodies were used together with content/h1v517777n768x1l/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">_h-EP tracer derivatives that were biotinylated in positions 24, 28, and 29 via a C₆ spacer arm. Nonspecific binding of biotinylated derivatives to the microtiter plates was blocked with a mixture of 1% casein and 10% ethanolamine in 0.1 M NaHCO₃. A sequential saturation procedure using a high-affinity antiserum in combination with an avidin–alkaline phosphatase complex matched the sensitivity of reported radioimmunoassays (RIAs), with a detection limit of 0.5 fmol/assay. The intra- and interassay coefficients of variation were 5 and 12%, respectively. Results obtained by ELISA and RIA showed good correlations (r = 0.95). The content/h1v517777n768x1l/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-EP concentration in extracted rat plasma after high-performance liquid chromatographic (HPLC) fractionation was determined by this method to be 1600 fmol/ml.     

Cotinine determination by immunoassays may be influenced by other nicotine metabolites

Polyclonal rabbit anticotinine antiserum, which can be used for biomonitoring nicotine uptake by the determination of cotinine in body fluids, was checked by a competitive ELISA for its cross-reactivity with nine nicotine metabolites. The highest percentage of relative crossreactivity (about 30%) was observed with trans-3content/w1202211463l54w5/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-hydroxycotinine, a metabolite which is known to be excreted in 3-fold higher amounts than cotinine in the urine of human smokers. Therefore, it is possible that cotinine determinations performed by immunochemical methods — especially in urine — may yield overestimated cotinine concentrations.     

Induction of light hydrocarbon nephropathy by p-dichlorobenzene

In order to clarify the etiology of a dose-related increase in the incidence of tubular cell adenocarcinomas of the kidney in male rats, the nephrotoxicity of p-dichlorobenzene (p-DCB) was investigated in a subchronic study. Groups of ten male and ten female Fischer 344 rats were dosed by gavage with 0 (controls), 75, 150, 300 or 600 mg p-DCB/kg/day in corn oil. Half of the animals were sacrificed after 4 weeks and the remainder after 13 weeks. Increased urinary LDH and epithelial cell excretion and exacerbation of hyaline droplet accumulation in the cytoplasm of renal cortical cells were observed in male rats over the entire dose range investigated. Tubular single cell necrosis, dilated tubules with granular cast formation in the outer zone of the medulla, were evident in male rats after 4 and 13 weeks of treatment with doses of 150–600 mg/kg/day. In female rats there was no indication of a nephrotoxic action of p-DCB. The effects on the kidney, both in their morphological characteristics and the fact that they occur exclusively in male animals, correspond to the light hydrocarbon nephropathy observed as a result of short-term treatment with a number of aliphatic and cyclic hydrocarbons. The development of cortical renal tumors seems to be associated with this kind of kidney damage which is unique to male rats. The literature on this subject generally regards these renal effects as not predictive for man.     

Thiol Reduction of 3′-Azidothymidine to 3′-Aminothymidine: Kinetics and Biomedical Implications

The ability of thiols to reduce 3content/t48jt274574gh5r2/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-azidothymidine (AZT) to 3content/t48jt274574gh5r2/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-aminothymidine has been investigated. Incubation with glutathione, dithiothreitol (DTT), or mercaptoethanol at pH 7.2 and 37°C leads to quantitative reduction of the azido moiety to an amine. The reaction is first order in AZT and first order in reducing agent (mono- or dithiol). The second-order rate constants are 2.77 × 10^–3, 6.55 × 10^–5, and 6.35 × 10^–6 M ^–l sec^–1 for the dithiothreitol, glutathione, and mercaptoethanol reductions, respectively. The thiol reduction of alkyl azide to amine under mild conditions is a synthetic method particularly suitable for water-soluble azido compounds that are sensitive to catalytic hydrogenation. The potential for the mono- or dithiol-mediated reduction of alkyl azides under biological conditions must be considered when conducting studies of azido drugs.     

Changes in ultrastructure of hepatocytes and liver test results before,during, and after treatment with interferon-β in patients with HBeAg-positive chronic active hepatitis

We studied the histological and ultrastructural changes in the liver and alterations in the liver test results before, during, and after treatment with human interferon-content/n2p4756502774qr7/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"> from five patients with hepatitis B e antigen-positive chronic active hepatitis. A daily dose of 3×10⁶ to 6×10⁶ units of interferon-content/n2p4756502774qr7/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"> was given intravenously for four weeks. The total index of periportal and portal inflammation, intralobular degeneration, and focal necrosis before treatment was decreased significantly six months after treatment (P<0.05). Ultrastructurally, the structure of endoplasmic reticulum was irregularly shaped or fragmentally decreased during treatment, but these disappeared six or 12 months after treatment. Glycogen particles diminished greatly during treatment. The alanine aminotransferase concentrations in these patients increased during treatment. Serum albumin and cholinesterase levels decreased significantly at the fourth week of treatment (P<0.01) and at the third day (P<0.01) to the second week (P<0.05) of treatment, respectively. These results suggest that interferon-content/n2p4756502774qr7/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"> injures endoplasmic reticulum and glycogen areas and damages the cholinesterase activity in the early stage of treatment and protein synthesis in patients with hepatitis B e antigen-positive chronic active hepatitis.     

Histochemical study of pituitary adenomas with Ki-67 and anti-DNA polymerase α monoclonal antibodies,bromodeoxyuridine labeling,and nucleolar organizer region counts

Summary The growth potential of 65 pituitary adenomas was determined by histochemical analysis with Ki-67 and anti-DNA polymerase content/v5240658vrn8m001/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"> monoclonal antibodies, bromodeoxyuridine (BrdUdR) labeling, and counts of argyrophilic nucleolar organizer regions (Ag-NORs). The mean proliferating cell indices (PCIs) determined by Ki-67 and anti-DNA polymerase content/v5240658vrn8m001/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"> and the BrdUdR labeling index (LI) were generally very low [1.0±0.2%, 1.1±0.2%, and 0.5±0.1% (±SE), respectively]. Apart from adrenocorticotropic hormone-positive adenomas, which had significantly higher indices, there were no statistically significant differences in the indices among the other subtypes of pituitary adenomas. Recurrent tumors had higher Ki-67 and DNA polymerase content/v5240658vrn8m001/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"> PCIs and BrdUdR LIs (3.6%, 4.2%, 1.4%) than primary tumors (0.8%, 0.8%, 0.3%; P<0.005). The number of Ag-NORs did not correlated significantly with any of the three indices. The mean number of Ag-NORs was higher in nonfunctioning adenomas than in functioning adenomas (2.04 vs 1.66, P<0.005); among prolactin-positive adenomas, those treated preoperatively with bromocriptine had more Ag-NORs than untreated tumors (1.75 vs 1.57, P<0.005). These results suggest that the Ki-67 and DNA polymerase content/v5240658vrn8m001/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"> PCIs and the BrdUdR LI predict the growth potential of individual pituitary adenomas, whereas the number of Ag-NORs appears to correlate with hormone production rather than with the proliferative potential.Supported by grants CA-13525 and CA-50210 from the National Cancer Institute, by a grant from the Phi Beta Psi Sorority, and by Grant-in-Aid A 63771083 from the Ministry of Education, Science, and Culture of Japan