In vitro antimicrobial activity of nanoconjugated vancomycin against drug resistant Staphylococcus aureus

The mounting problem of antibiotic resistance of Staphylococcus aureus has prompted renewed efforts toward the discovery of novel antimicrobial agents. The present study was aimed to evaluate the in vitro antimicrobial activity of nanoconjugated vancomycin against vancomycin sensitive and resistant S. aureus strains. Folic acid tagged chitosan nanoparticles are used as Trojan horse to deliver vancomycin into bacterial cells. In vitro antimicrobial activity of nanoconjugated vancomycin against VSSA and VRSA strains was determined by minimum inhibitory concentration, minimum bactericidal concentration, tolerance and disc agar diffusion test. Cell viability and biofilm formation was assessed as indicators of pathogenicity. To establish the possible antimicrobial mechanism of nanoconjugated vancomycin, the cell wall thickness was studied by TEM study. The result of the present study reveals that nano-sized vehicles enhance the transport of vancomycin across epithelial surfaces, and exhibits its efficient drug-action which has been understood from studies of MIC, MBC, DAD of chitosan derivative nanoparticle loaded with vancomycin. Tolerance values distinctly showed that vancomycin loaded into nano-conjugate is very effective and has strong bactericidal effect on VRSA. These findings strongly enhanced our understanding of the molecular mechanism of nanoconjugated vancomycin and provide additional rationale for application of antimicrobial therapeutic approaches for treatment of staphylococcal pathogenesis.

The Physicochemical Characterization and In Vitro/In Vivo Evaluation of Natural Surfactants-based Emulsions as Vehicles for Diclofenac Diethylamine

Two sugar-based emulsifiers, cetearyl alcohol & cetearyl glycoside and sorbitan stearate & sucrose cocoate, known as potential promoters of lamellar liquid crystals/gel phases, were investigated in order to formulate an optimal vehicle for amphiphilic drug - diclofenac diethylamine (DDA). Physico-chemical characterization and study of vehicle's physical stability were performed. Then, the in vitro DDA liberation profile, dependent on the mode of drug incorporation to the system, and the in vivo, short-term effects of chosen samples on skin parameters were examined. Droplets size distribution and rheological behavior indicated satisfying physical stability of both types of vehicles. Unexpectedly, the manner of DDA incorporation to the system had no significant influence on DDA release. In vivo study pointed to emulsion's favorable potential for skin hydration and barrier improvement, particularly in cetearyl glycoside-based vehicle.

Functional studies of the effect of NO donor on human CLCN1 polymorphism/mutants expressed in Xenopus laevis oocytes

In this study, we investigated the effect of NO donor, diethylamine/nitric oxide (DEA/NO), on the electrophysiological behavior of human skeletal muscle chloride channel (CLCN1). The wild-type and variants of CLCN1, including one polymorphism (P727L) and four mutants (T631I, D644G, G482R, and S471F), were expressed in Xenopus oocytes and the ionic current was measured by two-electrode voltage-clamp method. Our results revealed that there is no significant difference in the current-voltage relationships and half-voltage values of open probability between wild-type and variants of CLCN1 except for G482R. Application of the DEA-NO (0.1mM) significantly increases the channel conductance of wild-type, T631I, D644G, and S471F, but not P727L. This indicates that P727L polymorphism causes loss of sensitivity of CLCN1 to the DEA/NO treatment, which could be due to a conformational change caused by proline substitution. The data suggest that the polymorphic changes may affect the function of CLCN1 in response to the treatment of chemical compounds.

Peripheral nerve avulsion injuries as experimental models for adult motoneuron degeneration

We have used adult rat peripheral nerve avulsion models to evaluate the effects of neuroprotective molecules on motoneuron degeneration. The right facial nerves of adult Fischer 344 male rats were avulsed and adenoviral vectors encoding glial cell line-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF), transforming growth factor-beta2 (TGFbeta2), and growth inhibitory factor (GIF) were injected into the facial canal. The treatment with the vectors significantly prevented the loss of lesioned facial motoneurons, improved choline acetyltransferase (ChAT) immunoreactivity and suppressed the induction of nitric oxide synthase activity in these neurons. In separate experiments, animals were orally administered a solution of a neuroprotective compound T-588 after avulsion. Both free oral administration and oral tube administration of T-588 improved the survival of injured motoneurons and ameliorated their ChAT immunoreactivity. These results indicate that the gene transfer of GDNF, BDNF, TGFbeta2, and GIF and oral administration of T-588 may prevent the degeneration of motoneurons in adult humans with motoneuron injury and motor neuron diseases.

T-588 protects motor neuron death following axotomy

R(-)-1-(benzo [b] thiophen-5-yl)-2-[2-(N,N-diethylamino)ethoxy] ethanol hydrochloride) (T-588) enhances acetylcholine release. This compound slows the motor deterioration of wobbler mouse motor neuron disease and enhances neurite outgrowth and choline acetyltransferase activity in cultured rat spinal motor neurons. We examined the ability of T-588 on axotomized spinal motor neuron death in the rat spinal cord. After the postnatal unilateral section of sciatic nerve, there was approximately a 50% survival of motor neurons in the fourth lumbar segment. In comparison with vehicle, intraperitoneal injection of T-588 for 14 consecutive days rescued spinal motor neuron death. Our results showing in vivo neurotrophic activity of T-588 for motor neurons support the applicability of T-588 for the treatment of motor neuron diseases, such as amyotrophic lateral sclerosis and motor neuropathies.

T-588, a novel neuroprotective agent, delays progression of neuromuscular dysfunction in wobbler mouse motoneuron disease

R(-)-1-(benzo[b]thiophen-5-yl)-2-[2-(N,N-diethylamino) ethoxy]ethanol hydrochloride (T-588) enhances acetylcholine release from the frontal cortex and hippocampus in rats, and can ameliorate cognitive dysfunction in various amnesia models of rodents. T-588 protects rat cerebellar granule cells from glutamate neurotoxicity in culture. This agent also inhibits facilitation in the crayfish neuromuscular junction and mammalian cerebellum. Clinical trials of T-588 are underway in patients with Alzheimer's disease. We attempted to determine whether T-588 treatment ameliorates neuromuscular dysfunction in the wobbler mouse, an animal model of motoneuron disease (MND). After the initial diagnosis of MND at the age of 3-4 weeks, wobbler mice were orally administered T-588 (3, 10, 30 mg/kg) or vehicle daily for 4 weeks in a blinded fashion. We compared symptomatic, pathological and biochemical changes among the groups. In comparison with vehicle, T-588 administration potentiated grip strength, attenuated forelimb contracture and increased the weight of the biceps muscles. T-588-treated mice had retarded denervation muscle atrophy and elevated activities of choline acetyltransferase (ChAT) or lactate dehydrogenase in the biceps muscles. T-588 treatment also enhanced ChAT activities and promoted formation of cyclic adenosine monophosphate in the cervical cord. Pharmacokinetic study also showed that T-588 was transported efficiently into the cerebrum and spinal cord following oral administration. Thus, T-588 treatment delayed the progression of wobbler murine MND. Our findings suggest that this agent has therapeutic potential in human motor neuropathy or MND.

The effects of T-588, a novel cognitive enhancer, on noradrenaline uptake and release in rat cerebral cortical slices

Previously, we reported that (R)-(-)-1-(benzo[b]thiophen-5-yl)-2-[2-(N,N-diethylamino)-ethoxy]e thanol hydrochloride (T-588), a novel cognitive enhancer, stimulated noradrenaline (NA) release from rat cerebral cortical slices. In this study, we investigated the effects of T-588 on NA uptake and release, compared to the effects of desipramine, a blocker of the NA carrier on the plasma membrane. Both T-588 and desipramine caused dose-dependent inhibition of [3H]NA uptake into the slices. Addition of 3 mM T-588 stimulated [3H]NA release from the prelabeled slices even in the presence of 10 microM desipramine, which inhibited NA uptake completely. Tyramine, which accelerates NA carrier-mediated release, also stimulated [3H]NA release, and tyramine-stimulated release was inhibited by desipramine. These findings indicated that T-588-stimulated NA release was not mediated by 1) inhibition of reuptake or 2) reverse transport mediated by NA carriers. Reserpine, which interacts with the intracellular vesicular transport system, increased [3H]NA efflux from slices. High K+-, not T-588-, stimulated [3H]NA release was shifted upward by reserpine. These findings suggest that T-588 evokes NA release by a mechanism similar to that induced by reserpine. T-588 might act as a cognitive enhancer via neurotransmitter release in the brain.

[Effects of iron deficiency on toxic action of nitrites and endogenous synthesis of N-nitrosamines]

Separate or joint ingestions of water solutions of sodium nitrite and/or N-diethylamine by rats fed iron deficiency diet caused sharp increasing of N-nitrosodiethylamine level in stomach, a decreasing of Hb and increasing of MetHb concentrations in blood of animal. These effects were greater on iron deficient diet than on control diet. The nitrite ingestion caused a decline level of cytochrome P-450 and inhibition of lipid peroxidation in rat liver.

Inhalation of diethylamine--acute nasal effects and subjective response

Adult volunteers were exposed to 25 ppm (75 mg/m3) diethylamine in a climate chamber for 15 min in order to study the acute nasal reactions to an exposure equivalent to the present threshold limit value-short-term exposure limit. Changes in nasal volume and nasal resistance were measured by acoustic rhinometry and by rhinomanometry. Acute change in nasal volume, usually seen as acute nasal mucosa response to thermal stimuli, was not observed, nor was an acute change in nasal airway resistance. In a subsequent experiment, the aim was to measure acute sensory effects. Exposure to a concentration increasing from 0 to 12 ppm took place for 60 min, equal to an average concentration of 10 ppm (30 mg/m3). A moderate to strong olfactory response and distinct nasal and eye irritation were observed. In spite of considerable individual variation, the results were in agreement with sensory effect estimates obtained from animal studies.

Effects of administration of N-nitrosodialkylamines and N-nitrodiethylamine on hepatic UDP-glucuronosyltransferase activity in Wistar rats

N-Nitrosodiethylamine (NEN) and N-nitrodiethylamine (NEA) are carcinogens and in vitro activators of hepatic UDP-glucuronosyltransferase (GT) toward 2-aminophenol (AP) and 4-nitrophenol (NP). In this communication, they were intraperitoneally administered to male Wistar rats for 7 days and GT activities were determined towards AP, NP, phenolphthalein (PH) and testosterone (TS). Administration of 30 or 20 mg/kg dose of NEN caused marked decrease of liver and body weights, and did not affect hepatic GT activities. Injection of 10 mg/kg dose of NEN did not diminish liver and body weights, and increased the maximally activated GT activities toward AP and NP. In contrast, 30 mg/kg dose of NEA, did not affect either liver and body weights or GT activities. N-Nitrosodimethylamine (NMN), which is a carcinogen and a weak in vitro AP GT activator, was more toxic than NEN, and 3.6 mg/kg dose of NMN appears to induce GT toward NP and AP. Administration of 46.5 mg/kg N-nitrosodibutylamine (NBN), which is a carcinogen but not a GT activator, did not affect GT activities or liver body weights.

Differential motor effects of intraventricular infusion of morphine and etonitazene

The motor effects produced by intraventricular infusions of morphine were compared to the effects of etonitazene. Despite the similarity in the peripheral actions of these drugs, motor effects of central infusions differed dramatically. Intraventricular morphine infusions resulted in explosive motor behavior whereas etonitazene produced extreme muscular rigidity. The periaqueductal grey (PAG) has been proposed as the substrate of morphine-induced explosive motor behavior. However, considerations of the dose of morphine and the mobility of this drug in tissue suggests that sites other than the PAG may also be involved in explosive motor behavior.

Schedule-induced oral self administration of etonitazene

Rats were induced to drink either a saline-etonitazene solution or a saline solution with a schedule-induced polydipsia paradigm. When water was freely available, the rats continued to drink the saline solution or the saline-etonitazene solution, rather than the water. When the locations of the solutions were switched, the rats that were drinking saline switched to water (drank at the usual location), but the rats that were drinking saline-etonitazene continued to drink the saline-etonitazene solution (drank from the bottle at the other location). Naloxone administration temporarily eliminated the drinking of saline-etonitazene solution, but not that of saline solution.

Stimulation of sympathetic cardiovascular centres by RA 642, a new pyrimido-pyrimidine derivative

RA 642, 2,2'-[14,8-bis(diethylamino)-pyrimido[5,4-d] pyrimidine-2,6-diyl)di-(2-methoxyethyl)-imino]diethanol, has formerly been described to hypertensive when administered systemically. In the present experiments injection of 50 mug/kg RA 642 into the vertebral artery (i.a. vert.) of the cat exerted hypertension, while the same dose given intravenously (i.v.) elicited no effect. Since the drug was still effective in cats of which the brain was removed rostrad of the myelencephalon but not in spinal animals, its site of action was concluded to be in cardiovascular centres of the medulla oblongata. An i.a. vert. injection increased total peripheral resistance of the vasculature. The electrical discharge rate in preganglionic cervical sympathetic nerve fibres increased in parallel to the arterial blood pressure following the i.v. injection of 1 mg/kg of the substance. 1 mg/kg RA 642 i.v. decreased the reflex bradycardia elicited by the i.v. injection of angiotensin in dogs pretreated with a beta-adrenoceptor blocking drug to study the vagal effector reactions of the baroreceptor reflex, and treated with clonidine to facilitate the reflex. Thus, RA 642 increased sympathetic and, following clonidine treatment, decreased vagal reflex activity. RA 642 stimulated the respiration by a central action. The drug had no convulsant action.

Opioid-reinforced operant behavior: selective suppression by alpha-methyl-para-tyrosine

Morphine-addicted rats performed operant responses for opioid or milk rewards. When rats were then denied access to opioids, abstinence symptoms developed. Responding under extinction conditions 2 wk. after opioid withdrawal provided a measure of the "relapse" tendency. Systemic administration of DL-alpha-methyl-para-tyrosine, an inhibitor of catecholamine synthesis, suppressed these responses if they had been reinforced by an opioid but not if they had been established with milk reinforcement. This indicates that the integrity of the catecholamine systems is vital for relapse to occur.

Nuclear bodies produced in astrocytes by tilorone

Large, eosinophilic, nonglycogenic nuclear inclusions were produced in the central nervous system by the drug tilorone. At the light microscope level, the inclusions occurred predominantly in astrocytes. Ultrastructurally, they were identical to the nuclear bodies described in many cell types under many conditions. The bodies were produced by tilorone in small numbers in the median eminence, a part of the hypothalamus that lacks a blood-brain barrier. They were produced in only 2 or 3 days in large numbers adjacent to zones of thermal or traumatic necrosis or in areas of inflammation. These facts, and the distribution of affected astrocytes, indicated that permeability factors and cerebrospinal fluid flow were involved in the development of the nuclear bodies. The large size and large number of nuclear bodies produced by tilorone should facilitate studies of this poorly understood nuclear organelle.

Long-term chelation therapy in thalassaemia major: effect on liver iron concentration, liver histology, and clinical progress

A prospective trial of continuous chelation therapy in children with homozygous thalassaemia on a high transfusion regimen was started in April 1966. The effect of treatment on iron concentration in the liver and on hepatic histology was examined in 49 biopsy specimens obtained from nine chelator-treated patients and nine control patients between April 1966 and April 1973.Chelation therapy was associated with a significant reduction in liver iron concentration, and by the end of the trial the values for the two groups showed no overlap. A similar difference was seen in the amount of hepatic fibrosis, which showed little or no change in the chelator-treated patients but was progressive in the controls.No major clinical differences were seen, probably because both groups included several older children who were heavily loaded with iron at the start of the trial. Among the younger patients, however, puberty was delayed in four of five controls but in only one of four chelator-treated children. Prepubertal growth rate was significantly greater in the chelator-treated patients than in the controls.

Blockade of the surge of prolactin at pro-oestrus by administration of anti-oestrogenic substance, MER-25

A non-steroidal oestrogen antagonist, MER-25, was administered to cycling rats for elucidating the role of oestrogen in the surge of prolactin observed on the afternoon of pro-oestrus (POe).

In animals injected with 20 mg of MER-25 intramuscularly on the afternoon (16.30 h) of the first day of dioestrus (D-1), the surge of prolactin was blocked while the level of prolactin on the afternoon of POe of these animals was significantly higher than that of the corresponding controls injected with oil. Ovulation was also blocked in these animals treated with the drug on the afternoon of D-l. On the other hand, treatment on the morning (10.30 h) of the 2nd day of dioestrus failed to prevent not only the surge of prolactin but also ovulation.

These observations provide strong evidence for the view that oestrogen is responsible for the surge of prolactin on the afternoon of POe, and that the surge is accompanied by that of LH.