Selenium in the anterior pituitary of the rat after a single injection of75Se sodium selenite

In order to investigate the selenite metabolism in the anterior pituitary and compare it with other endocrine organs, rats were injected intraperitoneally with⁷⁵Se sodium selenite (5 mg/kg). The rats were whole body counted shortly after injection and recounted just before sacrifice, which was performed 2, 24, 48 h, and 4, 10, 20, 30, 40, 60, and 80 d after injection. Besides the anterior pituitary, the selenium content was also estimated in the thyroid gland, testis, adrenals, liver, kidney, and blood. The maximum selenium content was observed in all organs 2 h after injection, at which time the anterior pituitary contained 2.9 μg/g wet wt, compared to 13.5 μ/g wet wt in liver and .6 μg/mg wet wt in testis. The excretion of selenite from the anterior pituitary resembled that seen in most other organs investigated, i.e., an initial rapid excretion and a slower secondary phase resembling a first order reaction. Practically all selenium was excreted by 60 d after injection.     

The distribution and half-life for retention of vanadium in the organs of normal and diabetic rats orally fed vanadium(IV) and vanadium(V)

The concentration of vanadium in organs of diabetic rats that had been fed vanadium, either as V(IV) or V(V), in their drinking water has been determined. The kidney was found to have the highest concentration, about 185 nmol/g wet tissue. This averages about three times higher than for the liver or spleen, for which concentrations were comparable. The lung, blood plasma, and blood cells tended to have the lowest accumulations of vanadium. A time-course study indicated that the half-life for elimination of vanadium from the bodies of vanadium-fed rats is about 12 d.     

Effect of zinc on biological half-lives of 65Zn in whole body and liver and on distribution of 65Zn in different organs of rats following nickel toxicity

This study was designed to determine the effect of zinc on the biological half-lives of ⁶⁵Zn in whole body and liver and on distribution of ⁶⁵Zn in different organs of rats following nickel toxicity. Sprague-Dawley (SD) rats received either nickel in the form NiSO₄·6H₂O at a dose of 800 mg/L in drinking water, zinc in the form of ZnSO₄·7H₂O at a dose of 227 mg/L in drinking water, and nickel plus zinc or drinking water alone for a total duration of 8 wk. All of the rats were injected with a tracer dose of 0.37 MBq ⁶⁵Zn at the end of the treatment period. The effects of different treatments were studied on biological half-lives of ⁶⁵Zn in whole body and liver and on the distribution of ⁶⁵Zn in different organs of rats. In the present study, we have noted that nickel treatment to normal rats caused a significant decrease in the slow component (Tb₂) in liver, which improved following zinc supplementation. Nickel administration to normal-diet-fed animals caused significant lowering in the percentage uptake of ⁶⁵Zn values in the brain, liver, and intestine. However, the administration of zinc to nickel-treated rats improved the status of ⁶⁵Zn in different organs. The Tb₂ in the liver and the percentage uptake of ⁶⁵Zn values elevated following zinc supplementation to nickel-treated rats.     

65Zinc uptake from blood into brain and other tissues in the rat

Zinc is essential for normal growth, development and brain function although little is known about brain zinc homeostasis. Therefore, in this investigation we have studied⁶⁵Zn uptake from blood into brain and other tissues and have measured the blood-brain barrier permeability to⁶⁵Zn in the anaesthetized rat in vivo. Adult male Wistar within the weight range 500–600 g were used.⁶⁵ZnCl₂ and [¹²⁵I]albumin, the latter serving as a vascular marker, were injected in a bolus of normal saline I.V. Sequential arterial blood samples were taken during experiments that lasted between 5 min and 5 hr. At termination, samples from the liver, spleen, pancreas, lung, heart, muscle, kidney, bone, testis, ileum, blood cells, csf, and whole brain were taken and analysed for radio-isotope activity. Data have been analysed by Graphical Analysis which suggests⁶⁵Zn uptake from blood by all tissues sampled was unidirectional during this experimental period except brain, where at circulation times<30 min,⁶⁵Zn fluxes were bidirectional. In addition to the blood space, the brain appears to contain a rapidly exchanging compartment(s) for⁶⁵Zn of about 4 ml/100g which is not csf.     

Distribution of 1,5-anhydro-D-glucitol in normal, diabetic, and perfused rat bodies.

The concentration of 1,5-anhydro-D-glucitol (AG) was determined in various organs and tissues of normal rats and rats rendered diabetic with streptozocin, using an AG-assay method in which AG was extracted after acid hydrolysis of the whole tissues. The organs and tissues examined included skin, muscle, liver, and kidney. The plasma of control rats contained 3-12 micrograms/ml of AG. In these rats, all the organs examined also contained AG at concentrations not much lower than that in the corresponding plasma, except for adipose tissues and testis, which have relatively small water spaces; the latter two contained AG at relatively low concentrations. In contrast, both the plasma and various organs of the diabetic rats contained only trace amounts of AG. The whole body perfusion of control rats depleted AG from most of the organs, the exception being spleen, the circulation system of which is known to have a structure that is difficult wash by means of perfusion. These observations indicated that AG readily diffused into the inter- and intra-cellular water spaces from the circulation. Accordingly, the plasma membranes of the cells in these organs were suggested to be permeable to AG.     

Modeling the time dependent biodistribution of Samarium-153 ethylenediamine tetramethylene phosphonate using compartmental analysis

Aim

The main purpose of this work was to develop a pharmacokinetic model for the bone pain palliation agent Samarium-153 ethylenediamine tetramethylene phosphonate ([¹⁵³Sm]-EDTMP) in normal rats to analyze the behavior of the complex.

Background

The use of compartmental analysis allows a mathematical separation of tissues and organs to determine the concentration of activity in each fraction of interest. Biodistribution studies are expensive and difficult to carry out in humans, but such data can be obtained easily in rodents.

Materials and methods

We have developed a physiologically based pharmacokinetic model for scaling up activity concentration in each organ versus time. The mathematical model uses physiological parameters including organ volumes, blood flow rates, and vascular permabilities; the compartments (organs) are connected anatomically. This allows the use of scale-up techniques to predict new complex distribution in humans in each organ.

Results

The concentration of the radiopharmaceutical in various organs was measured at different times. The temporal behavior of biodistribution of ¹⁵³Sm-EDTMP was modeled and drawn as a function of time.

Conclusions

The variation of pharmaceutical concentration in all organs is described with summation of 6–10 exponential terms and it approximates our experimental data with precision better than 2%.     

Hypoglycemic effect of Belamcanda chinensis leaf extract in normal and STZ-induced diabetic rats and its potential active faction

Belamcanda chinensis (Iridaceae) belongs to the family of iridaceae and its rhizoma has been widely used for the treatment of throat ailment. Here we report a new pharmacological activity of B. chinensis leaf extract (BCL), that is, the hypoglycemic effect in normal and STZ-induced diabetic rats. Animals either healthy or STZ-induced diabetic show significantly lowered fasting blood glucose levels after treatment with BCL. The serum insulin concentration in normal rats is also enhanced. Additionally, the increase in blood glucose levels after administration of various carbohydrates in normal rats is significantly decreased and the oral glucose tolerance (OGTT) of STZ-induced diabetic rats is largely improved by BCL treatment. However, co-administration of BCL with Nifedipine, a Ca²⁺ ion channel blocker, or Nicorandil, an ATP-sensitive K⁺ ion channel opener thoroughly abolishes the hypoglycemic effect of BCL. HPLC analysis and compound identification showed that several isoflavone glycosides with antidiabetic activities were contained in BCL while pharmacological experiment showed that the polysaccharide fraction of BCL had no significant hypoglycemic effect on normal rats. Therefore, the isoflavone glycosides but not polysaccharides might be the active fraction of BCL in diabetes treatment.     

Increased Lipid Peroxidation and Ascorbic Acid Utilization in Testis and Epididymis of Rats Chronically Exposed to Lead

The hypothesis has been recently presented that lead may exert its negative effect at least partially through the increase of reactive oxygen species (ROS) level in tissues. However, little is known about the influence of lead intoxication on equilibrium between generation and elimination of ROS in the male reproductive system. Sexually mature male Wistar rats were given ad libitum 1% of aqueous solution of lead acetate (PbAc) for 9 months. Significantly higher lead concentrations were found in blood [median 7.03 (Q25–Q75: 2.99–7.65) versus 0.18 (0.12–0.99) μg dl⁻¹, P < 0.01], caput epididymis [median 5.51 (Q25–Q75: 4.31–7.83) versus 0.51 (0.11–0.80) μg g⁻¹ d.m., P < 0.001], cauda epididymis [median 5.88 (Q25–Q75: 4.06–8.37) versus 0.61 (0.2 – 1.08) μg g⁻¹ d.m., P < 0.001] and testis [median 1.81 (Q25–Q75: 0.94–2.31) versus 0.17 (0.03–0.3) μg g⁻¹ d.m., P < 0.01] of lead-intoxicated rats when compared to the control. The concentration of ascorbyl radical, generated in vitro from l-ascorbic acid (present in tissues in vivo) was measured by means of Electron Paramagnetic Resonance (EPR) spectroscopy. The EPR signal of ascorbyl radical in caput epididymis, cauda epididymis, testis and liver of lead acetate-treated animals revealed a significant decrease by 53%, 45%, 40% and 69% versus control tissues, respectively. Plasma l-ascorbic acid content measured by high performance liquid chromatography (HPLC) method and total antioxidant status (TAS) measured by means of spectrophotometry were also significantly lower in the intoxicated versus control animals (28% and 21%, respectively). In the group exposed to lead the concentration of lipid peroxide in homogenates of the reproductive system organs was significantly elevated versus control group. It can be assumed that the lower EPR signal was caused by decreased tissue concentrations of l-ascorbic acid. The latter may have resulted from consumption of ascorbic acid for scavenging of ROS excess in tissues of animals chronically exposed to lead.     

Iron Oxide Nanoparticle Assisted Purification and Mass Spectrometry Based Proteolytic Mapping of Intact CD4+T Cells from Human Blood

Abstract

Iron oxide nanoparticles have been used for many years as clinical applications. We have developed a rapid immunoaffinity isolation method of CD4⁺T cells from a mixed cell population of human blood using iron oxide nanoparticles. Anti CD4-antibody has been attached to iron oxide nanoparticles after its surface modification. The antibody tagged iron oxide nanoparticle beads are simply incubated with the mixed cell population of human blood and CD4⁺T cells are purified using an external magnetic field. The purification level was checked by fluorescence microscopy and flow cytometry. The purified CD4⁺T cells were digested with trypsin with different time periods and the products were analyzed by MALDI-TOF mass spectrometry, without further fractionation or purification, to obtain its proteome pattern. A database search showed a number of peptide masses matched specific to T-cell peptide masses. These results indicate that iron oxide nanoparticles are useful for CD4⁺T cell purification, and mass spectrometry based proteolytic fingerprint is simple and swift for identifying putative surface biomarkers from the whole cell surfaces.     

Effects of selenium deficiency on Ca transport function of sarcoplasmic reticulum and lipid peroxidation in rat myocardium

Two groups of weanling Sprague-Dawley rats were fed a low-selenium basal diet (Se 0.009 mg/kg) and the same diet supplemented with sodium selenite (Se 0.25 mg/kg), respectively, for 1, 2, and 3 months. At each feeding time, the Ca²⁺-ATPase activity, Ca²⁺ uptake rate and the capacity of Ca²⁺ uptake in isolated cardiac sacroplasmic reticulum from the Se-deficient rats were decreased significantly compared to those from the Se-supplemented rats, the contents of lipid peroxide in postmitochondrial supernatant and isolated sarcoplasmic reticulum from the Se-deficient rats were significantly higher than that from Se-supplemented rats. Compared to the Se-supplemented rats, the cytosolic glutathione peroxidase activity in Se-deficient rats decreased significantly. In addition, significant linear negative correlations of lipid peroxide in postmitochondrial supernatant to sarcoplasmic reticular Ca²⁺-ATPase activity, Ca²⁺ uptake rate and to whole blood selenium concentration were observed. The results suggest that the enhancement of lipid peroxidation via the depressed glutathione peroxidase activity might be responsible for the decrease of Ca²⁺-ATPase and Ca²⁺ uptake activities in sarcoplasmic reticulum in Se-deficient animals.     

Inhibition of isoproterenol-induced DNA and RNA synthesis in rat parotid and pancreas following removal of submandibular-sublingual glands

Summary [³H] thymidine incorporation into DNA of the parotid (PA) gland of adult and 20-day-old rats and into DNA of the pancreas (PANC) of 20-day-old rats was increased markedly following a 2-day regimen of isoproterenol (ISO) administration. However, when the submandibular-sublingual (SM-SL) glands had been removed just prior to initiation of the ISO injections, the [³H] thymidine incorporation into PA and PANC was inhibited, and cpm/mg protein of these organs was even lower than that of organs of untreated rats with SM-SL glands present. Removal of the PA glands just prior to initiation of the ISO regimen had no effect on the ISO-induced [³H] thymidine incorporation into DNA of PANC but partially inhibited that of the submandibular (SM) gland. It is suggested that the inhibitory effects on DNA and RNA synthesis that follow removal of SM-SL glands are attributable to the growth factors (epidermal growth factor and nerve growth factor) found in the rat SM gland. These factors appear to regulate normal DNA synthetic activity of exocrine glands as well as ₁-adrenoceptor mediated DNA synthesis. Cellular hypertrophy induced by the ISO was less markedly affected by absence of the SM glands, but a partial inhibition of [³H] uridine incorporation into RNA of PA of adult rats also occurred when SM-SL glands were removed prior to initiation of the ISO-regimen.     

Cellular and tissue distribution of potassium: Physiological relevance,mechanisms and regulation

Potassium (K⁺) is the most important cationic nutrient for all living organisms. Its cellular levels are significant (typically around 100 mM) and are highly regulated. In plants K⁺ affects multiple aspects such as growth, tolerance to biotic and abiotic stress and movement of plant organs. These processes occur at the cell, organ and whole plant level and not surprisingly, plants have evolved sophisticated mechanisms for the uptake, efflux and distribution of K⁺ both within cells and between organs.     

Uptake and retention in suckling rats of51chromium fed with human milk or infant formulas

Optimum concentration of Cr for infant formulas has not been established. Such components as soy protein or supplemental Fe could influence absorption and retention. Suckling rat pups were used to evaluate the influence of three commercial formulas and human milk, all of which had been incubated with⁵¹CrCl₃ for 1 h, on the uptake and retention of the added⁵¹Cr. After fasting 3 h, the pups were intubated with a single dose of 25 μCi⁵¹CrCl₃ in either a cow's milk-based formula, an Fe-supplemented cow's milk-based formula, a soy-based formula, or human milk. Six hours later,⁵¹Cr was counted in five organs, thymus, blood, and total urine. Absorption of⁵¹Cr was low. At 6 h, percent⁵¹Cr in blood was <0.2% of the dose, and total⁵¹Cr excretion in urine was <1.8%. The uptake and retention of⁵¹Cr and its concentration in any of the organs, thymus, blood, and urine were not influenced by different types of formula or by human milk.     

Nitric oxide is involved in the upregulation of IFN-γ and IL-10 mRNA expression by CD8⁺ T cells during the blood stages of P. chabaudi AS infection in CBA/Ca mice

Nitric oxide (NO) is involved in the clearance of several types of bacteria, viruses and parasites. Although the roles of NO and CD8⁺ T cells in the immune response to malaria have been extensively studied, their actual contributions during the blood stages of malaria infection remain unclear.In this work, we corroborate that serum NO levels are not associated with the in vivo elimination of the blood stages of Plasmodium chabaudi AS. In addition, we show that CD8⁺ T cells exhibit increased apoptosis and up regulate the expression of TNF-α mRNA on day 4 post-infection and IFN-γ and IL-10 mRNA on day 11 post-infection. Interestingly, only the levels of IFN-γ and IL-10 expression are affected when iNOS is inhibited with aminoguanidine (AG), suggesting that NO could be involved in the activation of CD8⁺ T cells during the blood stages of plasmodium infection.     

Ameliorative effects of l-carnitine on rats raised on a diet supplemented with lead acetate

Lead intoxication has been a major health hazard in humans. It affects people at all ages. Its toxicity is associated with various organs of the body and affects different metabolic pathways. Based on histological data, l-carnitine reduced the severity of tissue damage produced as a result of exposure of rats to lead acetate. The main objective of this study was to evaluate the underlying mechanism of protection offered by l-carnitine against lead acetate intoxication using male Sprague–Dawley rats.Forty male Sprague–Dawley rats were randomly divided into four groups with ten rats in each. The first group (G1) served as the control group and animals received standard diet only. The second group (G2) received lead acetate in their diet. The third group (G3) was the l-carnitine treated group and received the normal standard diet supplemented with l-carnitine. While the fourth group (G4) had a diet supplemented with both lead acetate and l-carnitine. At the end of each experiment, blood (serum and whole blood) were collected from each animal and analyzed for the following parameters: serum testosterone levels, serum nitric oxide and serum malondialdehyde. This is in addition to looking at the enzymatic activities of two important enzymes (superoxide dismutase and catalase) and on (glutathione reductase) which are indicative of the antioxidant activities in the whole blood. The results indicated that l-carnitine will counteract the undesirable effects of lead intoxication. It exerted its antioxidant potential by reducing the production of ROS and scavenging free radicals by maintaining and protecting the level of the of antioxidant enzymes SOD, CAT and glutathione peroxidase.Conclusion:l-Carnitine may play an important role in reversing the undesirable effects of lead intoxication. Future studies should be conducted to see whether such an effect is applicable in humans exposed to lead poising.     

NMR studies of malaria P nuclear magnetic resonance of blood from mice infected with Plasmodium berghei

High resolution ³¹P-NMR has been used for the non-invasive observation of metabolites and metabolic rates in blood of normal mice and of mice infected with Plasmodium berghei, the causative agent of malaria. ³¹P-NMR was used to quantitate levels of 2,3-diphosphoglycerate in whole cells as a function of the degree of parasitemia and yielded good agreement with the results of enzymatic assays. The time-dependence of ³¹P metabolites was monitored in both normal and infected erythrocytes, greater rates of decay of 2,3-diphosphoglycerate being observed in malarial blood which correlate with the level of parasitemia. Very high metabolic rates of infected cells render measurement of intracellular pH unreliable on freshly drawn whole blood. When appropriate measures are taken to avoid this complication, no difference is observed in the intracellular pH of parasitized and non-parasitized erythrocytes from infected animals. In both normal and parasitized mice the intraerythrocytic pH is more acidic than that of the suspending medium by 0.15 pH unit at 25°C. Unlike free-living protozoa, the parasitic protozoan Plasmodium does not contain detectable levels of phosphonates or polyphosphates, in either whole cells or perchloric acid extracts thereof.     

Anticonvulsant mechanisms of piperine,a piperidine alkaloid

Piperine, a natural compound isolated from the fruits of Piper, is known to modulate several neurotransmitter systems such as serotonin, norepinephrine, and GABA, all of which have been linked to the development of convulsions. Fruits of Piper species have been suggested as means for managing seizure disorders. The present study was designed to elucidate the anticonvulsant effect of piperine and its mechanisms of action using in-silico, in-vivo and in-vitro techniques.PASS software was used to determine its possible activity and mechanisms. Furthermore the latency for development of convulsions and mortality rate was recorded in different experimental mouse models of epilepsy (pentylenetetrazole, maximal electroshock, NMDA, picrotoxin, bicuculline, BAYK-8644, strychnine-induced convulsions) after administration of various doses of piperine (5, 10 and 20 mg/kg, i.p.). Finally, the effect of piperine on Na⁺ and Ca²⁺ channels were evaluated using the whole cell patch clamp techniqueOur results revealed that piperine decreased mortality in the MES-induced seizure model. Moreover, piperine (10 mg/kg) delayed the onset of tonic clonic convulsions in the pentylenetetrazole test and reduced associated mortality. Furthermore, an anticonvulsant dose of piperine also delayed the onset of tonic clonic seizures in strychnine, picrotoxin and BAY K-8644. Complete protection against mortality was observed in BAYK-8644 induced convulsions. Finally, whole cell patch clamp analysis suggested an inhibitory effect of piperine on Na⁺ channels. Together, our data suggest Na⁺ channel antagonist activity as a contributor to the complex anticonvulsant mechanisms of piperine.     

Effect of lead on the erythrocyte (Ca2+,Mg2+)-ATPase activity Calmodulin involvement

Summary I have investigated the effect of lead on the erythrocyte ghosts (Ca²⁺,Mg²⁺)-ATPase, with special attention to the role of calmodulin in this phenomena. Under regular incubation conditions, lead inhibits the enzyme with an IC₅₀ of 6.0 µM. The presence of exogenously added calmodulin apparently does not change this inhibitory value. DTT added during the incubation period does not affect the inhibitory action of lead. However, when the membranes are preincubated with DTT, an important IC₅₀ displacement is observed, either with or without added calmodulin. Since [¹²⁵I]calmodulin binding to the membranes is enhanced when lead is used, the possibility of a lead/calmodulin complex that optimally stimulates the enzyme using lead concentrations between 1.0 and 10.0 µM, is suggested. Based on the experimental data, I propose two well defined actions of lead; first, an inhibitory action upon the ATPase above 1.0 µM lead, most probably related to essential sullphydryl groups in the enzyme; and second, a direct action of lead upon calmodulin at lead concentrations below 1.0 µM.A preliminary report has been presented at the 5^th European Bioenergetics Conference. Aberystwyth, Wales. 20–26 July 1988. EBEC Reports. vol 5; p294 (1988).     

Use of EPR spectroscopy to check the changes in organism radioresistance. Experimental results

The responses of dNTP, DNA, and protein synthesis systems in blood-forming organs of animals (dogs, mice) as well as changes in blood Fe³⁺-transferrin (Fe-TF) and Cu²⁺-ceruloplasmin (Cu-CP) pools upon γ-irradiation and administration of radioprotectors have been studied. It is shown that changes in Fe-TF and Cu-CP pools are indices of change in body radioresistance and are reliably checked by the EPR technique. An increase in the Fe-TF pool promotes the activation of synthesis of dNTP, DNA, and Fe³⁺-containing proteins, which are essential for repair efficiency during early postirradiation time as well as for the development of compensatory-restorative reactions of cellular systems; i.e., they are responsible for body resistance to DNA-damaging factors. It is important that the intensity of responses depends on the initial state of the organism. Thus, dogs with initial individual characteristics of blood typical of “depressed” or “activated” states had abnormally high responses to irradiation at low doses of 0.25 and 0.5 Gy. This fact is important for estimating the consequences of prolonged low-dose irradiation for the human population. It has been shown that radioprotectors efficient in the survival test activate the synthesis of dNTP, DNA, and proteins in organs. The intensity of dNTP synthesis and the time when dNTP pools become maximal determine the efficiency of protectors and the time of irradiation after their administration.     

Specificity of ligand binding to transport sites: Ca2+ binding to the Ca2+ transport ATPase and its dependence on H+ and Mg2+

Ligand binding to transport sites constitutes the initial step in the catalytic cycle of transport ATPases. Here, we consider the well characterized Ca²⁺ ATPase of sarcoplasmic reticulum (SERCA) and describe a series of Ca²⁺ binding isotherms obtained by equilibrium measurements in the presence of various H⁺ and Mg²⁺ concentrations. We subject the isotherms to statistical mechanics analysis, using a model based on a minimal number of mechanistic steps. The analysis allows satisfactory fits and yields information on occupancy of the specific Ca²⁺ sites under various conditions. It also provides a fundamental method for analysis of binding specificity to transport sites under equilibrium conditions that lead to tightly coupled catalytic activation.