Effect of γ-radiation on some elements in certain organs of albino rats

Energy-dispersive X-ray fluorescence (EDXRF) was used to determine the concentrations of Ca, Cl, Fe, Ni, P, K, Se, S, and Zn in heart, lung, liver, spleen, and kidney of adult albino rats 2 mo after they were subject to a single gamma γ-radiation dose from⁶⁰Co at 5 gy. In female rats, K levels were significantly higher and the Ca levels significantly lower for the irradiated animals when compared to age-matched nonirradiated controls. Significant differences between irradiated and nonirradiated tissues were observed for other elements, although no sex-related differences could be found. Tissue damage and disturbances of biological functions were observed as a result of γ-irradiation.     

Effect of anticancer drugs on the release of interferon γ in vitro

Summary Some conventional and experimental anticancer drugs were tested for their effect on concanavalin-A-induced interferon release from rat splenocytes in vitro. When 2.5 × 10⁶ rat splenocytes/ml, stimulated with 1 µg/ml concanavalin A, were incubated with various non-cytotoxic doses of the vinca alkaloid vincristine, there was an inhibition of the release of interferon in culture supernatants. The antitumour antibiotics bleomycin and Adriamycin, alkylating agents 4-hydroperoxycyclophosphamide and mafosfamide, and the immunoactive peptides FK 156 and FK565 did not affect the release of interferon under similar conditions. However, cyclosporin A, in similar experiments, markedly inhibited the release of interferon .     

Metabolic fates of 2′-deoxy-5-[18F]fluorouridine in tumor-bearing mice and human plasma

The metabolic fate of 2′-deoxy-5-[¹⁸F]fluorouridine ([¹⁸F]FdUrd), a useful positron emission tomography (PET) tracer of nucleic acid metabolism in tumors, was investigated in mice and humans. A rapid increase in labeled catabolites was found in mouse and human plasma. In mouse FM3A mammary carcinoma, the corresponding catabolites were also detected in addition to metabolites which were activated by the nucleic acid metabolism. From a biodistribution study of β-[³H]alanine, α-[¹⁸F]fluoro-β-alanine, a major catabolite, was assumed to be taken up twice as much by tumor than by the brain. Nucleic acid metabolism in brain tumors by [¹⁸F]FdUrd-PET may be assessed using normal brain regions as a reference.     

Effect of prostaglandins E2 and F2α on in vitro development and hatching of caprine blastocysts

Prostaglandin E₂ has been shown to increase the ovine embryo hatching rate, and PGF_2α to reduce the development of rabbit, bovine, and rat embryos. The objective was to determine the effects of PGE₂ and PGF_2α on development of caprine embryos. Estrus was synchronized in does (n = 25) with medroxyprogesterone acetate (MAP) intravaginal sponges for 12 days, and superovulated with 20 units of FSH. On day 6 following estrus, embryos were flushed (n = 128) and incubated individually per well in 25 μl droplets of TCM-199 and BSA (8 mg/ml) for 6 days at 38.5 °C in a 5% CO₂: air with one of the following treatments: (1) control (0.0002% EtOH), (2) PGE₂ (7 ng/ml), (3) PGF_2α (7 ng/ml), (4) low PGE₂:high PGF_2α (3.5 ng/ml:14 ng/ml), (5) balanced PGE₂:PGF_2α (7 ng/ml:7 ng/ml), or (6) high PGE₂:low PGF_2α (14 ng/ml:3.5 ng/ml). Treatment with PGE₂ alone reduced (P < 0.05) the hatching rate (1/15; 7%). The hatching rate of embryos treated with PGF_2α alone (9/18; 50%), low PGE₂:high PGF_2α (8/16; 50%), and balanced PGE₂:PGF_2α (11/16; 69%) were similar to control (6/18; 33%). In contrast, the hatching rate was non-significantly increased (13/18; 72%) with the high PGE₂:low PGF_2α treatment. None of the treatments affected development from the morula to blastocyst stage. From the current data, it can be concluded that PGE₂ alone reduced hatching rate, and PGF_2α alone had no effect on the development of caprine embryos. High concentrations of PGE₂ with PGF_2α improved the hatching rates. Thus, uterine concentrations of PGE₂ may need to reach a threshold level to improve embryo hatching, as previously reported, while increased uterine concentrations of PGF_2α during early pregnancy would not affect development of the embryo.     

Androgen dynamics in vitro in the human prostate gland. Effect of oestradiol-17β

Normal, hyperplastic and adenocarcinomatous human prostatic tissue was perfused in vitro with radioactively labelled androstenedione, testosterone and 5alpha-dihydrotestosterone with and without added oestradiol-17beta. Various parameters of tissue-steroid relationship were measured at the steady state. When oestradiol (0.11 or 0.22mumol/l) was added to the perfusing medium, the entry of the steroids into the tissue and their metabolism was increased in the majority of the glands studied. The ;uptake' of all the steroids varied, in response to the addition of oestradiol, in both normal and adenocarcinomatous glands in a way differing from the response of hyperplastic glands. As a consequence, the tissue clearance of the steroids, particularly of androstenedione and testosterone, increased in normal and adenocarcinomatous glands in the presence of oestradiol, and decreased in the hyperplastic tissues. At a concentration 0.33mumol/l, oestradiol decreased the entry of the steroids in all the tissues studied, while the clearance of steroids tended to decrease. The significance of these findings in terms of the regulation of androgen dynamics in vivo in the normal and diseased human prostate, with particular regard to the response to oestrogen treatment, is discussed.     

Effect of γ-Decanolactone on Glutamate Binding in the Rat Cerebral Cortex

Epilepsy is one of the most common neurological disorders. Even though antiepileptic drugs can afford a reasonably satisfactory treatment for 80% of diagnosed patients, chronic intractable epilepsy still affects a significant number of people and more effective and less harmful antiepileptic drugs are needed. Previous studies have shown that -decanolactone has dose-dependent sedative effects, including hypnotic, anticonvulsant and hypothermic properties in mice. The present study reports an inhibitory effect of -decanolactone on glutamate binding (96.8% with 5 mM) in rat cortex membranes. The non competitive nature of glutamate binding inhibition as a neurochemical correlate of the anticonvulsant activity of -decanolactone may be a relevant mode of action for further drug development.     

Ontogeny of the enzymes related to γ-glutamyl cycle in the human fetal system

Measurements have been made of the enzymes associated with γ-glutamyl cycleviz, γ-glutamyl transpeptidase, γ-glutamyl cysteine synthetase, and 5-oxoprolinase in human fetal brain, liver and kidney over 12–36 weeks of gestation. γ-Glutamyl transpeptidase activity increases gradually with age. γ-Glutamyl cysteine synthetase and 5-oxoprolinase show biphasic pattern of development in human fetal brain. The data presented in this communication may indicate a relationship between γ-glutamyl cycle and amino acid transport.     

Effect of ethanol on the response of the rat urinary bladder to in vitro ischemia: Protective effect of α-lipoic acid

Purpose: Ethanol exposure has been used to demonstrate the increase of oxidative stress to a variety of tissues. We studied the effect of ethanol on the response of isolated strips of rat bladder to In vitro hypoxia in the absence of glucose (In vitro ischemia). Secondly, we determined if -lipoic acid (LA) could alter the response to ethanol + In vitro ischemia.Methods: Sixty-four rats were used for the these experiments. Each rat was anesthetized and its urinary bladder excised. The bladder body was cut into two longitudinal strips and each strip mounted in individual baths filled with oxygenated Tyrodes solution containing glucose at 37 C. Ethanol (0.3%, 1%, or 3%) was placed in the first six baths (two strips at each concentration). The last two baths did not receive ethanol. Each strip was incubated for 1 h and then stimulated with field stimulation at 2, 8, and 32 Hz. Each strip was stimulated with 10 M carbachol, washed three times with fresh oxygenated buffer and ethanol re-added to their respective baths. Each strip was then stimulated with 120 mM KCl and washed three times as before. Strips were then subjected to 1 h In vitro ischemia (incubation in the absence of glucose with Tyrodes equilibrated with nitrogen instead of oxygen). During the ischemic period, each strip was stimulated for 5 s every 10 min by 32 Hz FS to simulate hyperreflexia. At the end of the hour, the tissues were incubated for an additional hour in the presence of oxygen + glucose and subjected to a second series of stimulations as before. At all times, ethanol was maintained in baths 1–6. In set 2, 1% ethanol was added to the first six baths. LA was added to every other bath, and the experiments performed as mentioned earlier.Results: (a) Ethanol at 0.3% or 1% had no effect on the contractile responses prior to exposure to In vitro ischemia; 3% was inhibitory. (b) In vitro ischemia mediated a significant decrease in the contractile responses to all forms of stimulation except for carbachol. (c) Ethanol mediated a dose-response enhancement of the contractile dysfunctions caused by In vitro ischemia. (d) LA completely reversed the effects of ethanol on contractile responses following In vitro ischemia except for carbachol.Conclusions: The results demonstrate that direct exposure to ethanol significantly enhanced contractile dysfunctions mediated by In vitro ischemia followed by re-oxygenation and that the presence of LA significantly inhibits this effect of ethanol. (Mol Cell Biochem 271: 133–138, 2005)This material is based upon work supported in part by the Office of Research and Development, Department of Veterans Affairs, and NIH RO-1-DK067114     

19F NMR studies of the binding of 5-fluoro-2′-deoxyuridylate to thymidylate synthase

Summary In the presence of thymidylate synthase, the ¹⁹F signal of 5-fluoro-2-deoxyuridylate is shifted upfield 0.6 ppm or 4.5 ppm depending on the enzyme preparation used. The bands at these positions represent different species of binary complex. When either binary complex is reacted with methylenetetrahydrofolate a ternary complex is formed with a ¹⁹F signal shifted 12.5 ppm upfield and broadened to 120 Hz.Substitution of the hydrogen atoms of the methylene group of methylenetetrahydrofolate with deuterium atoms results in line-narrowing of the spectrum of the ternary complex from 120 to 80 Hz indicating the close proximity of the methylene group to the fluorine atom in the ternary complex. A model compound, 5-fluoro-6-hydroxy-5-methyl-5, 6-dihydrouracil, gives a chemical shift in the same direction and of similar magnitude to that seen with the ternary complex.     

The effect of water loading on the urinary ratio of cortisone to cortisol in healthy subjects and a new approach to the evaluation of the ratio as an index for in vivo human 11β-hydroxysteroid dehydrogenase 2 activity

Factors that give rise to a large variation in the urinary ratio of free cortisone to cortisol (UFE/UFF) were investigated to accurately estimate 11β-hydroxysteroid dehydrogenase 2 (11β-HSD2) activity in humans in vivo. A water loading test was first carried out in two healthy subjects to examine the effect of water intake or urine volume on the urinary ratio of free cortisone to cortisol (UFE/UFF). The ratio was found to increase by water loading. We also examined urinary concentrations and amounts of cortisol, cortisone, creatinine, Na(+), K(+), and Cl(-), and urine volume, as possible factors affecting the urinary ratio (UFE/UFF), in 60 urine samples obtained from 15 healthy volunteers. Among these factors tested, the urinary concentration of cortisol was most highly correlated with the UFE/UFF ratio (r=-0.858), indicating that the in vivo activity of 11β-HSD2 (UFE/UFF) should fluctuate with the changes of the urinary concentration of cortisol. Based on the findings, we proposed a new estimation method of in vivo activity of 11β-HSD2 in humans, using the UFE/UFF ratio correlated with the urinary concentration of cortisol (UFE/UFF-cortisol concentration). Taking into consideration the intra-individual variabilities in the urinary concentration of cortisol, there were no significant within-day variations in 11β-HSD2 activity. The findings indicate that 11β-HSD2 activities can be accurately evaluated by simply measuring free cortisol and cortisone concentrations in spot urine samples. Furthermore, administrations of glycyrrhetinic acid in three healthy volunteers were performed to confirm the usefulness of the present assessment for the activity of 11β-HSD2.     

Effect of 17β-estradiol on calcium response to phytohaemagglutinin in human lymphocytes

Pre-treatment of human lymphocytes with 17-estradiol diminishes the increase in concentration of cytosolic free calcium after stimulation with phytohaemagglutinin. The effect is dependent on 17-estradiol concentration and on the preincubation time. The effect is not due to an interaction between 17-estradiol and phytohaemagglutinin, but appears to be a consequence of the binding of the hormone to the cell surface. The effect is specific for 17-estradiol, since the isomer and other steroid hormones (progesterone, testosterone, diethylstilbestrol and 5-androstan), have no effect. Since the effect of the 17-estradiol can be suppressed by treatment of lymphocytes with ouabain, it appears that the effect of estradiol on the rise of cytosolic calcium induced by phytohaemagglutinin is mediated by the (Na, K)-ATPase.     

Effect of morphine and abstinence syndrome on [3H]bromoxidine binding to α2-adrenoreceptors in rat brain

At 4 days after the implantation of two subcutaneous 75 mg morphine pellets in the back skin, rats were morphine-dependent. In the three layers studied in the occipital cortex we found that the values of the ₂-adrenergic agonist [³H]bromoxidine binding increased with respect to animals implanted with placebo pellets. Typical behavioral and physiological symptoms of the abstinence syndrome appeared 30 minutes after administration of naloxone, [³H]bromoxidine binding values being similar to those obtained in animals implanted with placebo pellets. The pattern of response of the [³H]bromoxidine binding was similar in the hippocampus and the superficial gray layer of the superior colliculus of the mesencephalon, but the differences were not statistically significant in these areas. This paper concludes that exist brain regional differences in the ₂-adrenoreceptors response under morphine-treatment and possibly under naloxone-induced morphine abstinence syndrome.     

Effect of Pt and Sn on the adsorption of n-heptane in γ-Al2O3 catalyst models

The Grand Canonical Monte-Carlo (GCMC) method has been used to carry out simulations of the adsorption of n-heptane in models of naphtha-reforming catalysts. Models used in the study differed in the number and distribution of metal atoms—Pt and Sn. The number of adsorbed n-heptane molecules grows linearly with increasing number of metal atoms. The effect of Pt content on the adsorption of n-heptane molecules is most distinct at approximately 100 kPa and within the lower range of the temperatures investigated. In the models of bimetallic catalysts, the effect of the two metals is additive.Figure Effect of Pt and Sn on number of n-heptane molecules adsorbed in Al₂O₃ catalyst in 773 K and 1000 kPa.      

Effect of in vitro exposure of human serum to 3-butyl-1-phenyl-2-(phenyltelluro)oct-en-1-one on oxidative stress

Increased oxidative stress and impaired antioxidant defense mechanisms are believed to be the important factors contributing to the pathogenesis and progression of diabetes mellitus. In this study, we have reported the effects of the streptozotocin-induced diabetes on the gene expression and the activities of two antioxidant enzymes, manganese superoxide dismutase (MnSOD) and glutathione peroxidase (GPx). We also studied the effects of two antioxidants, vitamin C and DL-α-lipoic acid (LA), on the system. Our results showed no significant change in both enzymes activities in diabetic animals compared to controls. Similarly, mRNA and protein profiles of MnSOD showed no change. Though the mRNA expression of GPx did not show any change, Western-blot analysis results demonstrated that protein expression is increased. LA, which is a water- and lipid-soluble antioxidant, decreased the protein expression of MnSOD, though mRNA levels and activities remained unchanged. LA treatment increased the GPx activities in diabetic tissues, significantly, and RT-PCR and Western-blot analysis results demonstrated that this increase in activity is not regulated at the gene level, as both mRNA and protein levels did not change. Supplementing the animals with vitamin C, a powerful water-soluble antioxidant, increased the mRNA expression of MnSOD, though the protein expression and the activity did not change statistically. On the other hand GPx activity increased significantly through post-translational modifications, as both mRNA and protein expressions did not change. These results together with our previous findings about the gene expressions of catalase and Cu–Zn SOD indicate the presence of very intricate control mechanisms regulating the activities of antioxidant enzymes in order to prevent the damaging effects of oxidative stress.     

Effect of progesterone administration on the release of uterine prostaglandin F2α and ovarian oxytocin in the goat

The effects of intramuscular progesterone administration (20 mg·day⁻¹) on plasma concentrations of 13,14-dihydro-15-keto-prostaglandin F_2α (PGFM-pulmonary metabolite of prostaglandin F_2α) and oxytocin were examined in seventeen goats after either bilateral ovariectomy, hysterectomy or during days 12–16 of the estrous cycle. Daily mean values of PGFM in animals treated with progesterone after ovariectomy were significantly greater (P<0.001) than in their corresponding controls on the last two treatment days (10 and 11); concentrations of oxytocin, however, remained at or near the limits of assay sensitivity. In hysterectomized goats PGFM concentrations remained extremely low and oxytocin release appeared steady rather than pulsatile. In the intact animals, undergoing luteolysis, daily mean concentrations of both PGFM and oxytocin were significantly greater (P<0.01) in progesterone-treated goats than in their oil-treated controls; furthermore, in the progesterone-treated goats, increases in PGFM concentrations, observed after the peaks of progesterone, were either coincident with or prior to pulses of oxytocin. These results demonstrate that uterine PGF_2α stimulates the pulsatile release of oxytocin from the ovary during luteolysis in the goat.     

Effect of prostaglandin F2α on anterior pituitary function in man

Five healthy adult men received iv PGF_2α at dosages of 0.05, 0.20 and 2.0 μg/kg/min for 30 min. There were no significant changes in serum FSH, LH or TSH levels. Serum GH and cortisol levels were slightly increased at the highest dosage. These responses were associated with, and presumably a result of, stressful side effects. Thus, PGF_2α cannot be used as a provocative test of pituitary hormone reserve.Prostaglandins (PG's) have recently been implicated in the release of a number of hormones from the anterior pituitary gland. The stimulation of GH release by PG's of the E series from incubated rat pituitary slices has been demonstrated. $\text{In vivo}$ stimulation by PGE₁ of ACTH in rats and of GH release in man has also been shown.The present study was undertaken in order to examine the efficacy of iv administration of PGF_2α as a provocative test of anterior pituitary hormone reserve in man. The responses in circulating levels of gonadotropins, TSH, GH, and cortisol (as an index of ACTH) were measured.     

Acute effects of sodium valproate and γ-vinyl gaba on regional amino acid metabolism in the rat brain: Incorporation of 2-[14C]glucose into amino acids

Amino acid concentrations have been determined in rat brain regions (cortex, striatum, cerebellum, and hippocampus) by HPLC after administration of acute anticonvulsant doses of sodium valproate (400 mg/kg, i.p.) and -vinyl-GABA (1g/kg, i.p.). After valproate administration the GABA level increases only in the cortex; aspartic acid concentration decreases in the cortex and hippocampus, and glutamic acid decreases in the hippocampus and striatum and increases in the cortex and cerebellum. There are no changes in the concentrations of glutamine, taurine, glycine, serine, and alanine following valproate administration. Only the GABA level increases in all the regions after -vinyl-GABA administration. Cortical analyses 2, 4 and 10 minutes after pulse labeling with 2-[¹⁴C]glucose, i.v., shown no change in the rate of cortical glucose utilization in the valproate treated group. The rate of labeling of glutamic acid is also unchanged, but the rate of labeling of GABA is reduced following valproate administration. After -vinyl-GABA administration there is no change in the rate of labeling of GABA. These biochemical findings can be interpreted in terms of a primary anticonvulsant action of valproate on membrane receptors with secondary effects on the metabolism of amino acid neurotransmitters. This contrasts with the primary action of -vinyl-GABA on GABA-transaminase activity.This paper is dedicated to Dr. Derek Richter on his sevety-fifth birthday