Speract, a decapeptide from Strongylocentrotus purpuratus sea urchin eggs, transiently stimulates a membrane guanylyl cyclase and activates a K(+)-selective channel that hyperpolarizes the sperm. Membrane potential recordings with fluorescent dyes in sperm flagellar vesicles were used to determine if calmodulin participates in the signal transduction induced by speract. The vesicle hyperpolarization induced by speract was inhibited by the calmodulin antagonists: trifluoperazine, mastoparan; N-(6-Aminohexyl)-5-chloro-1-naphthalenesulfonamide, (W-7); and N-(6-Aminohexyl)-1-naphthalenesulfonamide, (W-5). Since that inhibition occurred at concentrations at which calmodulin action is inhibited by these compounds, the overall findings suggested that calmodulin could be involved in the speract response. The speract response was Ca(2+)-independent however. Ten millimolar EGTA does not inhibit the hyperpolarization and 2 mM BAPTA only partially inhibited the response. High concentrations of calmodulin-dependent kinase II and phosphatase inhibitors did not alter the response of the flagella vesicles to speract. Taken as a whole, these results indicate that the speract-induced hyperpolarization involves the participation of calmodulin in a Ca2+ independent manner.
Parkinson's disease (PD) is characterized by malfunction of dopaminergic systems, and the current symptomatic treatment is to replace lost dopamine. For investigating mechanisms of pathogenesis and alternative treatments to compensate lack of dopamine (DA) activity in PD, the 6-hydroxydopamine (6-OHDA)-lesioned rat model of PD has been useful, these animals display apomorphine-induced contralateral rotational behavior, when they are examined after lesion. The purpose of this study was to assess Titania-dopamine (TiO2-DA) complexes implanted on the caudate nucleus for diminishing motor behavior alterations of the 6-OHDA rat model. Rats with 6-OHDA unilateral lesions received TiO2 alone or TiO2-DA implants, and were tested for open field (OF) gross motor crossing and rearing behaviors, and apomorphine-induced rotation (G) behavior. TiO2 complex have no effects on rearing OF and G behaviors, and a significant reducing effect on crossing motor behavior of normal rats compared to control non-treated rats throughout 56 days of observation. Interestingly, TiO2-DA treatment significant recovered motor crossing and rearing behaviors in 6-OHDA-lesioned rats, and diminished the G behaviors during 56 days of examination. Additionally, in the 6-OHDA-lesioned rats TiO2 treatment had a moderate recovering effect only on crossing behavior compared to lesioned non treated rats. Our results suggest that continuous release of dopamine in the caudate nucleus from TiO2-DA complex is capable of reversing gross motor deficits observed in the 6-OHDA-lesioned rat model of PD. Thistype of delivery system of DA represents a promising therapy for PD in humans.
Tacrolimus is a macrolide immunosuppressant that is safe and effective for the prevention of rejection after kidney transplantation. The oral bioavailability of tacrolimus averages 20% to 25%; however, the inter-individual variability in this parameter is large. Because of the poor correlation of dose to blood concentration between patients, the variability in pharmacokinetics and a relatively narrow therapeutic window, therapeutic drug monitoring of tacrolimus trough whole blood concentrations must be a standard practice. The objective of this evaluation was to determine the relationship among changes in hematocrit, albumin, and corticosteroid dosing on the disposition of tacrolimus during 6 months of treatment in renal transplant recipients. Blood samples for the determination of trough tacrolimus concentrations were taken immediately prior to the morning dose, samples were collected according to the request of the attending physician. Clinical and dosage data were reviewed 6 months after transplantation. The analysis was conducted including 11 patients who were analyzed for hematocrit and albumin at the same time they are measured tacrolimus blood levels. The mean age was 25.3 years (range 17 to 41 years) 4 of the patients were female. Levels of tacrolimus, hematocrit and albumin over the first 24 weeks post-transplant were documented and the estimated relative clearance of tacrolimus were calculated. Statistical evaluation of the data indicates poor correlation between relative clearance and both hematocrit and albumin levels and the mean oral steroid dose. This observation is of clinical significance because dose adjustment may be required to maintain blood concentrations within thetherapeutic range in patients in whom hematocrit or albumin concentrations are changing.
The aim of this study was to evaluate the pharmacological effect of FL-6, a new immunomodulatory drug, in chronic hepatitis immunologically induced in rats via porcine-serum (PS) administration. Thirty-two male Wistar rats (150 g) were divided into 4 experimental groups: (1) Control (PBS 0.5 ml 3-times per week for 8-week); (2) FL-6 (50 ng/kg 3-times per week for 4-week); (3) Hepatitis (PS 373 mg/kg twice per week for 8-week); and (4) Hepatitis + FL-6 (doses as above). Rats were sacrificed at the end of treatment. ALT, AST, ALP and gamma-GT activities, as well as IL-6 and IL-10 levels, were evaluated in serum samples. Glutathione and malondialdehyde were also analyzed. A morphological analysis of liver tissue was carried out. The hepatitis group showed an increase in ALT (1.44-fold), AST (1.28-fold), ALP (1.83-fold), gamma-GT (3.91-fold), IL-6 (2.6-fold) and IL-10 (7.1-fold) levels when compared with controls (p < 0.05). Histopathological analysis revealed an inflammatory response characterized by inflammatory infiltrates and liver damage, which was accompanied by a reduction of 74.8% in glutathione levels (p < 0.05). However, animals with hepatitis treated with FL-6 had a reduction of ALT activity (17.74%), as well as a reduction in IL-6 (24.21%) and IL-10 (30.91%) levels (p < 0.05). These animals showed a reduction in inflammatory response characterized by a decrease in inflammatory infiltrate at the hepatic parenchyma and portal structures; livers showed less damage and a reduction of necrotic and apoptotic hepatocytes. In conclusion, the treatment with FL-6 improved liver function and reduced the inflammatory marker in rats with chronic hepatitis induced by PS-administration.
We studied the cellular damage in a patient with Dyke-Davidoff-Masson Syndrome and a history of chronic temporal lobe epilepsy resistant to treatment. The epileptogenic zone was localized to the right temporal lobe, and an extensive surgical removal of the temporal neocortex plus amygdala and hippocampus was performed. The specimens were immediately frozen in liquid nitrogen and stored at -75 degrees C for biochemical studies. Specimens were immersed and fixed in freshly prepared 4% paraformaldehyde for histopathological evaluation. Neurotransmitter levels were highest in the hippocampus compared to the temporal neocortex (T1, T2, and T3). In the amygdala, GABA was found whereas other amino acids were absent. We found marked dislamination in all areas of the cortex, neuronal loss, amylaceous bodies, and neuronal cytomegaly with cytoskeletal disorganization containing dense fibrillar cytoplasmic aggregates, nodular heterotopias, dysplastic and large neurons with high Nissl staining, intermixed with balloon cells with atypical nuclei, often with binucleation, and abundant glassy eosinophilic cytoplasm. Positive immunoreactive cells with nestin, vimentin, and enhanced expression of astrocytes were observed in all brain regions. This patient's syndrome should be considered as a postinfectious/post-stroke event that caused hemiparesis and later recurrent seizures. Higher expression of nestin and vimentin has been observed in proliferative neuronal cells, the expression in astrocytes may mainly reflect an early response of these cells to injury. Nestin may play a role in protecting the brain from injury. It has been proposed that re-expression of embryonic genes by mature cells is associated with morphological plasticity.
Streptozotocin (STZ) is used to induce experimental diabetes in rodents. There is however, controversy as to whether STZ induced diabetes models type 1 or 2 diabetes. We show that the grade of STZ-induced hyperglycemia in male CD1 mice is dependent on STZ dose. A single injection of high dose (130 or 150 mg/Kg body weight) or multiple injections (2, 3, 4 or 5) of low dose (40 mg/Kg body weight) STZ was administered intraperitonealy in non-fasted mice. Blood glucose and body weight were measured over 21 days for high dose and 21 and 28 days for low dose administration. On day three, high dose treatment produced hyperglycemia and body weight loss in comparison to mice without STZ, however unstable hyperglycemias and several deaths were observed during treatment. Hyperglycemia and body weight loss were seen with three or more injections of STZ at 21 days, whereas 4 and 5 injections produced severe hyperglycemia but not death. Mild hyperglycemia (250-450 mg/dL) was seen after 28 days following three injections of STZ. Therefore we concluded that a high dose STZ produces severe hyperglycemia in mice similar to a type 1 diabetic, and three successive administrations of STZ induces mild hyperglycemia in mice similar to type 2 diabetics.
Blindness is a pervasive sensory condition that imposes diverse difficulties to carry on with activities of daily living. In blind individuals, the brain is subjected to a large scale reorganization characterized by expanded cortical territories associated with somatosensory and auditory functions and the recruitment of the former visual areas to perform bimodal somatosensory and auditory integration. This poses obstacles to efforts aimed at reassigning visual functions to the recruited visual cortex in the blind, especially after the end of the ontogentic sensitive period. Devising pharmacological measures to modulate the magnitude of brain plasticity could improve our chances of recovering visual functions in the blind. Here, by using the primary somatosensory cortex (S1) in the rat as a working model, we showed that valproic acid administered through the mother's milk prevents cortical reorganization in blinded rats by delaying neuronal histone de-acetylation. These results suggest that in the future, we might be able to devise epigenetic pharmacological measures that could improve our chances of reassigning visual functions to the once deprived former visual cortex in the blind, by modulating the magnitude of brain plasticity during critical times of development.
We evaluated the therapeutic potential of LA-419, a hybrid organic nitrate that donates nitric oxide and thiol groups, to improve pulmonary arterial hypertension in an experimental model induced by monocrotaline in the rat. Treatment with LA-419 from the first day after monocrotaline administration prevented the increase in pulmonary pressure as well as the increases in ventricle/body weight and pulmonary artery wall thickness. Administration of LA-419 after establishment of hypertensive status also resulted in an improvement of these parameters. Both preventive and therapeutic treatments reduced mortality. The antioxidant effect of LA-419 was comparable to that achieved with a-tocopherol. Pulmonary remodeling accomplished by LA-419 could be attributed to a balanced antioxidant effect associated with its nitric oxide/SH donor capability. Thus, LA-419 might represent a new therapeutic approach in severe pulmonary hypertension in humans.
Mycophenolate mofetil is an immunosuppressive pro-drug frequently used to prevent renal graft rejection. It is hydrolyzed by esterases to obtain the active drug mycophenolic acid (MPA). There is high inter-patient variation in mycophenolic acid pharmacokinetics. Area under the concentration versus time curve (AUC) is used for therapeutic drug monitoring and recommended levels are 30-60 microg x hr/L. The aim of this study was to determine mycophenolic acid pharmacokinetics in children awaiting renal allograft in order to predict mycophenolate mofetil dose requirements. Children with end-stage renal disease on the waiting list for renal allograft transplantation were invited to participate in the study. A nine-point pharmacokinetic profile was performed. All patients received a single dose (600 mg/m2, subcutaneously) of mycophenolate mofetil at time zero. Mycophenolic acid was measured by HPLC. The AUC0-12h was estimated by the trapezoidal rule. Ten children were included in the study. Mean age was 13.5 +/- 3.5 years. The median AUC0-12h was 20.3 microg x hr/L, median Cmax = 0.7 microg/mL. Two children (20%) had no detectable levels of mycophenolic acid after a single mycophenolate mofetil dose, other two patients had AUC > 60 microg x hr/L. One patient had abdominal pain 1 hr after the mycophenolate mofetil dose. Twenty percent of our patients had AUC0-12h higher than the recommended value after a single mycophenolate mofetil dose, those patients should receive lower mycophenolate mofetil dose since the beginning of the transplant to avoid adverse events, and another 20% of patients had no detectable mycophenolic acid levels after a single mycophenolate mofetil dose. UGT1A9 gene polymorphisms remain to be studied in our patients, since they could explain the differences in bioavailability.
The aim of this study was to evaluate the effect of orlistat, a drug used in weight loss, on 5-HT and indicators of oxidative stress in rat brain. Orlistat, 12 mg/kg was administered to Wistar rats as single dose or successive doses on 3 consecutive days. Blood glucose and oxidative stress indicators were detected by measurement of lipid peroxidation, Na+, K+ ATPase, glutathione and serotonin levels using previous validated methods. The levels of glucose decreased in rats receiving successive doses. The activity of Na+, K+ ATPase and total ATPase was reduced in rats receiving successive doses, while the level of lipid peroxidation increased slightly in both groups. Glutathione underwent significant reduction in the successive doses group (p < 0.05). 5-HT increased significantly after single dose treatment (p < 0.05). Orlistat can induce pro-oxidant effects in the brain due to alteration of serotonergic metabolism and the reduction of glutathione.
Peripheral arterial occlusive disease is described as vascular disorders associated with ischemia and may be the result of an obstructive vascular process or a lost revascularization response. We have shown that gait locomotion analysis by video filming represents an integrative model for the evaluation of mechanisms involved in the process of ischemia-induced revascularization. However, analysis by this method can be subjective and perception errors may be occurring. We present the optimization of a quantifiable, noninvasive, reproducible method that analyzes ankle kinematics in rats using a two-dimensional digital video system. Gait dynamics were filmed in hindlimb ischemic rats with a high speed digital video camera. Images were collected and analyzed at 125 frames per second. An algorithm using interactive data language (IDL) was devised to assess different parameters. In ischemic rats, stride time and knee joint angle remained altered 10 days post-surgery compared with sham animals. Gait kinematics were outlined in a highly reliable way by this computational analysis and corroborated the notion of hindlimb movement recovery associated with the revascularization process.
Information related to adverse drug effects caused by ocular medications and ocular adverse effects of systemically administered drugs has increased over the last several decades. Here we review the medical literature over the last four decades to both quantitatively and qualitatively determine the adverse effects of ocular drugs and ocular toxicity of non-ocular drugs. A systematic bibliographic review of the literature was performed with the following terms: "drug treatment", "drug therapy", "ocular adverse effects", "ocular side effects", "ocular toxicity", "systemic side effects", "systemic adverse effects", "systemic toxicity", "ocular drug" and "ophthalmic drug" using the Boolean operators or, and, not. Searches focused on: (1) Ocular side/adverse effects of ophthalmic drugs; (2) Ocular side/adverse effects of systemic drugs; (3) Systemic side/adverse effects of ophthalmic drugs. PubMed was used to perform searches. Limits included: species, human and field tag, abstract/title, dates from 01/01/1971 to 31/12/2010. A sub-selection of references was made by discarding articles that were irrelevant for the topics listed above. Adverse effects of alpha2-adrenergic agonists, beta-adrenergic antagonists, quinine derivatives and antituberculosis agents appear in the literature throughout the period of the review. Adverse effects of newer drugs such as amiodarone, phosphodiesterase 5 inhibitors, antiepileptics, tamoxifen, and its interactions have been published principally in the last two decades. It is imperative for patient safety that knowledge of the adverse effects of drugs on the eye whether topically or systemically administered, and the possible systemic effects of drugs given as ophthalmic medications be emphasized to clinicians.
Low brain serotonin levels and high circulating levels of corticosterone are features of migraine. The 5-HT7 receptor was shown to mediate dilator responses to the 5-HT1B/1D and 5-HT7 receptor agonist, 5-carboxamidotryptamine in the middle meningeal artery of rats. Here we analyzed the effect of serotonin depletion and chronic corticosterone treatment on 5-HT7 receptor-mediated dilatation induced by 5-carboxamidotryptamine in the middle meningeal artery of anesthetized rats. Two weeks before experiments, male Wistar rats received i.c.v. injections of vehicle or the neurotoxin, 5,7-dihydroxytryptamine; upon recovery, animals received a chronic s.c. treatment (2 weeks) with vehicle (1 ml/kg/day) or corticosterone (20 mg/kg/day). At the end of treatments, animals were anesthetized and prepared for recording of blood pressure and blood flow in the middle meningeal artery, and i.v. drug administration. All animals received the 5-HT1B/1D receptor antagonist GR-127935 (1 mg/kg, i.v.) alone or combined with the 5-HT7 receptor antagonist, SB-269970 (1 mg/kg, i.v.). Topical 5-carboxamidotryptamine (0.01-1000 microM) to the exposed dura mater encephala produced decreases in diastolic blood pressure, variable changes in meningeal blood flow and increases in conductance (i.e. dilatation) in the middle meningeal artery. Meningeal dilator responses to 5-carboxamidotryptamine did not differ among treatment groups. In all cases, the combined treatment with GR-127935 + SB-269970 inhibited hypotensive and meningeal dilator responses to 5- carboxamidotryptamine. Together, these data do not support the notion that 5-HT7 receptors mediating dilatation in the middle meningeal artery are regulated by low brain serotonin levels and/or chronically high circulating levels of corticosterone. Further studies are required to elucidate the potential impact of these conditions and the role of 5-HT7 receptors in migraine.
Ganoderma lucidum, a traditional Chinese medicine, has been shown to target the Central Nervous System. In this work we analyze whether G. lucidum, collected in Mexico, has a protective effect in the hippocampus of rats treated with kainic acid, a neurotoxin that causes seizures and neuronal loss. The aqueous extract of G. lucidum (10 mg/Kg, i.p.) was administered to rats 30 min before kainic acid injection (5 mg/Kg, i.p.). Animals that had received prior treatment with G. lucidum showed no tonic-clonic seizure activity. Histopathological analysis showed a significant decrease in neuronal loss and cellular alterations in the hippocampal CA3 region. Immunohistochemical analysis shows that when using G. lucidum in rats, there is less immunoreactivity for GFAP as well as TNF-alpha and IL-1beta in the CA3 region when compared with rats treated with kainic acid. Our results demonstrate that G. lucidum protects against kainic acid-induced alterations of hippocampal cells and expression of immunological markers in this model of excitotoxicity.
In their transit through the female genital tract, mammalian sperm acquire the ability to fertilize the egg in a process called capacitation. During this event the intracellular levels of cAMP and cGMP increase, suggesting that cyclic nucleotide-gated (CNG) channels, which have been identified in mammalian sperm, play a functional role in their physiology. Here we report an electrophysiological characterization of the effect of cyclic nucleotides on mouse sperm. Using the patch-clamp technique in the whole-cell configuration, we show that macroscopic ionic currents are augmented by the addition of both, 8Br-cAMP and 8Br-cGMP to non-capacitated mouse sperm. Although cyclic nucleotide regulates the activity of CNG channels, disparate effects of cyclic nucleotides may also occur. Addition of L-cis-diltiazem (50 microM), a specific inhibitor of CNG channels, partially blocked currents elicited by cGMP, suggesting that CNG channels play a role in the fertilization capability of mammalian sperm.
Teachers and researchers are valuable resources of universities. A healthy life style includes appropriate utilization of medicines. In this work we explore health status and medicine consumption among a sample of academic employees over 40 years of age at a Mexican university. We analyzed answers to an on line survey in a random sample of academic employees, 40 years and older who work at the National University of Mexico. The 179 item survey was answered from November 2009 to October 2010, by 240 randomly selected academic employees. A section of the questionnaire was oriented toward health issues. We analyzed reported illness, self-perception of health status and medicine consumption. The bodies systems involved most often among those who report any kind of disease were: circulatory and endocrine and/or metabolic, followed by osteomuscular and digestive. Medicinal agents were consumed in the last two weeks by 52% of respondents. Among these, vitamins were consumed by 28%, drugs for pain by 17%, drugs for high blood pressure by 14%, drugs for high cholesterol by 13%, antibiotics by 8%, drugs for diabetes by 5%, cold medicines by 4%. It is suggested that medicinal drugs may not be consumed in situations in which they are indicated, such as in hypercholesterolemia and possibly in hypertension and diabetes. Others, such as vitamins are frequently utilized. Research and interventions should be directed toward better utilization of medicinal drugs.
The renin-angiotensin system (RAS) is one of the most important systems in blood pressure homeostasis and pathogenesis of cardiovascular-renal diseases. When blood volume goes down, juxtaglomerular cells in the kidneys secrete renin. Renin stimulates the production of angiotensin I (Ang I), which is then converted to angiotensin II (Ang II). Angiotensin II causes blood vessels to constrict, resulting in increased blood pressure. If the renin angiotensin system is over active, blood pressure will be too high. Most hypotensive drugs are designed to block this system at different points in the pathway. In this study, we developed a mathematical model of the renin-angiotensin system to emulate the response of the renin-angiotensin system in humans. This model consists of a set of differential equations. Special attention is paid to the estimation of all the model parameters from reported experimental data. These equations allow us to model hypertensive and normotensive patients and pharmacotherapeutic approaches to treatment. We show dose-response curves of blood pressure and biochemical components of the renin-angiotensin system. Our results reproduce clinical outcomes. We conclude that mathematical modeling of RAS is a useful approach for gaining insight into the complexities of homeostatic control of arterial pressure and pharmacotherapeutics.
The aim of this review is to briefly describe some colorimetric methods that are commonly used to evaluate a new chemical entity (NCE) on cell cultures in non-clinical oncology discovery research. These methods have the distinct advantage over other techniques in that they can be applied and used in a cell monolayer or a suspension culture. Both protein assay determination and cell viability assays may be conducted using these culture systems. The viability of cell cultures is routinely assessed by utilizing the metabolic capacity of cells which biochemically convert chemicals (usually color dyes) which can then be conveniently measured at specific wavelengths using a multi-well plate reader. Resazurin (Alamar Blue) is an example of one of these metabolically active compounds. Resazurin is a nontoxic dye that can also be used to measure migration and cellular invasion without resorting to sacrifice of the cells during the test procedure. Another is 5-bromo-2-deoxyuridine (bromodeoxyuridine or BrdU) which is a thymidine analog that incorporates into the DNA of dividing cells during the S-phase of the cell cycle. We will also discuss the colorimetric version of the traditional 3H-thymidine incorporation and immunoenzymatic assay used to measure DNA synthesis and its application to discovery research.
Nitric Oxide (NO) is thought to play a fundamental role in the genesis and the spreading of epileptiform hyperactivity, although its function is unclear and controversial. As a free radical, NO may cause oxidative stress, which is emerging as an important mechanism in the etiology of seizure-induced neuronal death. Here we investigated the role of NO in seizure mechanisms through oxidative stress generation by studying the effect of anticonvulsant drugs such as amino oxyacetic acid (AAOA), valproate (VALP), diazepam (DIAZ) and gabapentin (GBPTNA) on oxidative stress in the brain, estimated as free carbonyls by the method of Dalle and Rossi, and by measuring NO by the indirect method based on the Griess reaction. Results show that, except for AAOA and VALP, anticonvulsants did not significantly affect or decreased free carbonyls, but reversed the oxidative stress produced by pentylenetetrazole (PTZ) induced convulsions. Anticonvulsants except AAOA diminished NO levels and with the exception of VALP, counteracted the increase in NO generated by PTZ. Anticonvulsants decreased oxidative stress and NO especially in hippocampus (HI) and cortex (CX), and reversed PTZ effects on both parameters. PTZ diminished NO in HI, which could be explained since PTZ caused an increase on endothelial NO synthase but a decrease in neuronal NOS expression in this brain area. Since the drugs studied are modulating GABA levels, our results suggest that seizures generated by alterations in GABAergic transmission produce oxidative stress caused by NO, which can be reversed by anticonvulsants. The effects described differ among the brain regions studied and the NO synthase isoform affected.
Measuring hepatic metabolic function is critical for detection and treatment of liver failure. Several tests have been widely used to characterize the integrity of liver; however, they do not evaluate the metabolic function of the organ, most requiring multiple blood draws. The purpose of this study was to establish if the ratio of the lidocaine metabolite monoethylglycinexylidide (MEGX) divided by lidocaine concentration at 30 min post intravenous lidocaine administration is a good marker of metabolic activity of the liver. Nine healthy and two partially hepatectomized and auto-transplanted dogs were included in the study. A single 1.5 mg/kg intravenous dose of lidocaine and serum samples were obtained at selected times for 150 minutes. Serum concentrations of lidocaine and MEGX were determined by a validated high-performance liquid chromatographic method. Pharmacokinetic parameters were obtained by non-compartmental methods and ratio of AUC of MEGX divided by AUC of lidocaine was determined for each dog. This ratio was correlated with the ratio of the concentration of the compounds obtained 30 minutes after drug administration. A good concordance was obtained, suggesting that ratio obtained with a single sample may be useful to predict the hepatic metabolism function. To validate the test, dogs hepatectomized and auto-transplanted were plotted and the results obtained were within the values obtained in healthy dogs. These results suggest that ratio of MEGX/lidocaine obtained 30 min after administration could be a good marker of hepatic metabolic function.
