Topical cyclosporine inhibits mast cell-mediated conjunctivitis

PURPOSE

Allergic conjunctivitis is a common condition caused by a mast cell-mediated hypersensitivity reaction to immunoglobulin E-bound allergens. The purpose of this study was to investigate the effect of topical cyclosporine A on the development of mast cell-mediated conjunctivitis in mice.

METHODS

Allergic conjunctivitis was induced in C57BL/6 mice by topical applications of compound 48/80, a mast cell degranulating agent. In two separate experiments, mice were treated with topical cyclosporine A (0.05%, 0.2%, or 0.4%), prednisolone acetate 1%, or phosphate-buffered saline. Twenty-four hours after compound 48/80 instillation, the number of neutrophils, eosinophils, lymphocytes, macrophages, and the number of preserved goblet cells and undegranulated mast cells in the conjunctiva were counted by a masked observer.

RESULTS

In both experiments, treatment with all three doses of cyclosporine A resulted in a statistically significant reduction in the number of infiltrating neutrophils and eosinophils compared to saline-treated controls. There was no significant difference in the treatment effect of cyclosporine and prednisolone acetate. In addition, there was increased preservation of goblet cells in the cyclosporine A-treated animals. Immunohistochemical staining showed a reduction in infiltrating lymphocytes and a smaller reduction in infiltrating macrophages in animals treated with cyclosporine compared to saline-treated controls.

CONCLUSIONS

Topical cyclosporine A was effective in inhibiting the development of mast cell-mediated allergic conjunctivitis in mice. This study suggests that topical cyclosporine A may be effective in treating allergic conjunctivitis in humans.

Laboratory evaluation on the toxic effects of bednets impregnated with permethrin against malaria mosquitos

In the laboratory, bednets impregnated with 250mg ai/m2 and 500mg ai/m2 permethrin caused respectively the mean mortalities of 86.6% within 13 months and 87.2% within 17 months on laboratory-bred An. sinensis, while they caused average mortalities of 58.3% within 4 months and 73.8% within 10 months on An. dirus respectively. The bioassay results of KT50 and LT50 on the two species showed that KT50 is shorter than LT50 after exposure to the treated bednets. The ratio is 1:2.16 - 1:3.05. It was observed Anopheles had obviously secondary knocked down after exposure to the treated bednets and there is obvious resurgent after Anopheles have been knocked down. When the temperature goes up the resurgence gets shorter, the resurgence rate gets higher and the mortality gets lower. It showed that permethrin has stronger knocking down effect than killing effect.

Role of dopamine D-1 and D-2 antagonists in a model of focal epilepsy induced by electrical stimulation of hippocampus and amygdala in the rabbit

1. The differential role played by blockade of D-1 or D-2 dopamine receptors in mechanisms underlying seizures was studied in a model of EEG after-discharge induced by electrical stimulation of selective brain regions (dorsal hippocampus and amygdala) in the rabbit. 2. The D-2 antagonist haloperidol (1 mg/Kg) increased significantly after-discharge duration after stimulation of either hippocampus or amygdala and lowered after-discharge threshold in few animals. 3. The D-1 antagonist SCH 23390 (0.3 mg/Kg) caused no changes following stimulation of amygdala and reduced after-discharge duration when hippocampus was stimulated. 4. Haloperidol exerted a proconvulsant action in this experimental model, having a clearer influence on D-2 receptors. SCH 23390 had no effect on amygdala whereas it exerted protection on the hippocampus. 5. The present data suggest that D-1 and D-2 receptors have different roles in generating and spreading the epileptic activity.

Familial hemiplegic migraine versus migraine with prolonged aura: an uncertain diagnosis in a family report

Four of five members of a family complained of repeated attacks of hemiplegic migraine, migraine with aura of different types, or migraine without aura. The hemiplegia always outlasted the headache and was often accompanied by altered consciousness, aphasia, and, in one patient, coma; in this latter patient, the ictal EEG, recorded during two attacks, showed delta activity in the hemisphere contralateral to the hemiplegia. At least 2 months after their latest attacks, three patients showed dyscalculia, attentional disturbances, and impaired long-term verbal memory on neuropsychologic assessment. There were no cognitive disturbances in the unaffected relative. The severity of cognitive impairment appears to be correlated with migraine history. We attempt to classify these cases according to the criteria of the International Headache Society.

Melatonin and cortisol circadian secretion during ethanol withdrawal in chronic alcoholics

Changes in central neurotransmission and in hypothalamo-pituitary function occur in both ethanol (ETOH) intake and withdrawal. Melatonin (MLT) secretion is regulated by the noradrenergic system, which is activated upon ETOH withdrawal. Experimental evidence exist that pineal gland may have a role in ETOH intake and preference in rats. Twenty-four hour urinary excretion of MLT was found to be increased during ETOH intake in chronic alcoholics. In this study we have determined 24h plasma levels of MLT and cortisol in 8 chronic alcoholic males hospitalized for a detoxication program and in 8 healthy controls. The study was performed just after admission, on the first day of ETOH withdrawal and after 14 days of controlled abstinence. Circadian periodicity has been evaluated by the cosinor method. The initial determinations corresponded to the acute withdrawal phase. Twenty-four hour plasma MLT mean levels on acute withdrawal were higher than after 14 days abstinence and than those found in controls. Large interindividual differences prevented the detection of statistical significance. The cosinor analysis disclosed the loss of circadian periodicity in the acute withdrawal. Significant 24h periodicity was restored after 14 days abstinence. Cortisol levels were significantly higher than those found on day 14 and in healthy controls. Twenty-four hour periodicity was maintained in both alcoholics series. A delay in cortisol acrophase occurred in acute withdrawal. The effects of Corticotropin Releasing Hormone infusion on cortisol secretion were significantly enhanced in the acute withdrawal phase in comparison with those occurring when patients were retested and with healthy controls.

Early effects of GM1 in experimental cerebral focal ischemia in rabbits

This study aimed to investigate the effects of monosialoganglioside (GM1) when administered early in a model of cerebral focal ischemia, in the rabbit. The statistical evaluation of the electroencephalographic changes (quantified EEG analysis, QEEG) due to the ischemic event showed that the early treatment (1-3-24 h) with GM1 reduced the EEgraphic pattern typical of this model of cerebral ischemia. Considering the observation period, we hypothesized that it was due to the formation of an oedema of a lesser degree compared to the untreated group. Particularly, we did not obtain the increase in delta activity on the contralateral hemisphere, which we thought was expression of the diaschisi phenomenon.

Eegraphic and behavioural effects of ondansetron, a 5HT3 antagonist, in rabbits

1. EEGraphic and behavioural effects of ondansetron, a 5HT3 antagonist, have been studied in the rabbit. Subsequently we tested the neurophysiological and behavioural interactions between ondansetron and L-5-HTP induced serotonergic syndrome. 2. The drug produced a dose-dependent (0.001, 0.01, 0.1 mg/kg i.v.) increase in the cortical power density spectrum, particularly in the range of the lowest frequencies bands. This effect is expression of cortical synchronization. 3. The lowest and mild dose, but not the highest, failed to produce behavioural sedation and to inhibit the arousal induced by vibroacustical stimulation. 4. L-5-HTP (10 mg/kg i.v.) administration generated a typical EEGraphic-behavioural pattern characterized by a decrease of cortical power spectrum density and stereotyped movements. The EEGraphic effects were significantly suppressed by administration of mild and higher doses of ondansetron, while the behavioural effects were inhibited by all doses tested. 5. It is concluded that ondansetron acts with considerably efficacy on central nervous system. The administration of low and mild doses shows a singular dissociation between EEGraphic and behavioural actions. The inhibition of the L-5-HTP behavioural syndrome by ondansetron suggests that this drug acts on behaviour only when there is an altered physiological pattern.

[Electroencephalographic effects of a new triazolobenzodiazepine (Adinazolam) in the rabbit]

In this study we investigated the central effects of adinazolam, a triazolobenzodiazepine, by means of neurophysiological techniques (electroencephalogram, EEG, and quantified analysis of EEG, QEEG). The drug has been administered at the doses of 0.1-1-10 mg/kg i.v. The evaluation of the data obtained by QEEG has demonstrated that this substance acts on the central nervous system. Particularly we observed that the drug at the middle and high doses caused an increase of the "slow waves sleep" EEG pattern. This preclinical study has shown that adinazolam possesses a neuropharmacological profile similar to that of atypical antidepressive and/or anxiolytic drugs.

[Role of the dopaminergic system in experimental models of epilepsy]

It has been shown that neuroleptics which interact selectively with either D-1 or D-2 dopamine receptors possess a marked difference in their propensity on seizures. The aim of this work was to investigate whether the D-1 antagonist SCH 23390 differs from haloperidol (D-2 antagonist) in models of experimental epilepsy induced by electrical stimulation of selected brain regions (hippocampus and amygdala), in rabbits. Haloperidol increased and SCH 23390 significantly decreased the susceptibility to seizures in both models investigated. The data suggest that the D-1 and D-2 receptor subtypes have different roles in the mechanisms underlying seizures.

Chiropractic complications. Another case report

We report the case of a 34-year-old man, treated by chiropractic manipulation for tension-type headache. The patient complained of a sharp occipital pain during the first session, followed by vomiting and loss of consciousness, and remained comatose for five days. Neurological examination detected persistence of dysarthria, ataxia, with delayed responses. Neuroradiological findings reveal an ischemic lesion in left PICA region, confirmed by angiography. Clinical and radiological findings suggested complete remission about two months later.

Neurophysiological parameters during halothane anaesthesia in experimental models of cerebral ischemia

Types of anaesthesia in different experimental models of ischemia vary, with consequent difficulties in analysis of results obtained by the authors. The aim of this work was to evaluate EEG and SEPs parameters in a group of rabbits submitted to anaesthesia with halothane. We used White New Zealand rabbits prepared for EEG recording according to the Monnier and Gangloff's stereotaxic method. SEPs were obtained by medial nerve stimulation according to a method standardized in our laboratory. Each animal was anaesthetized with halothane plus nitrous oxide and oxygen or halothane plus oxygen for surgical MAC, which was maintained for a time corresponding to the duration of surgical intervention. We evaluated all parameters in basal conditions and after the administration of anaesthesia until EEG and SEPs returned to basal values. Evoked potentials remained altered for a longer period of time and returned to basal levels only two hours after anaestethic suspension.

Comparative study of the EEG profile of neuroleptics selective for D-1 or D-2 dopamine receptors in the rabbit

The neuroleptics SCH 23390 and raclopride, which interact selectively with either D-1 or D-2 dopamine receptor, were studied for their effects on electroencephalographic (EEG) activity in the rabbit. Haloperidol (0.3 and 1 mg/kg intravenously, i.v.), which was used for comparison, induced synchronization of the cortical EEG activity. Spectral EEG analysis showed increase of power in the whole frequency range (0.1-38.5 Hz) and in all frequency bands in the cortex, whereas a slight decrease of slow and fast theta activity (3.7-7.2 and 7.2-12.2 Hz) was observed in the hippocampus. Animals appeared sedated and arousal response to somatosensory stimuli was markedly inhibited. SCH 23390 (0.03 and 0.3 mg/kg i.v.) induced periods of cortical synchronization and changes of spectral power qualitatively similar to those accompanying haloperidol administration. The drug slightly reduced the duration of arousal elicited by stimuli. Raclopride (1 and 3 mg/kg i.v.) induced weak EEG changes and little effect on arousal response to stimulation. There was an increase of slow wave activity which was particularly evident in the hippocampus. The data indicate that, although to a lesser degree, the D-1 receptor antagonist SCH 23390 induced EEG effects similar to those of haloperidol, whereas blockade of D-2 receptors by raclopride resulted in different patterns of EEG activity.

[The neuroendocrine aspects of chronic alcoholism: the effect of alcohol intake and its withdrawal]

Neuroendocrine dysfunctions, in part similar to those found in depression, are present in chronic alcoholism. The aim of this investigation was to evaluate the effects of chronic alcohol intake on cortisol secretion in basal conditions, after dexamethasone (DXT) suppression or corticotropin (ACTH) stimulation in 10 alcoholic men, during active drinking and after two weeks of alcohol withdrawal. The 24-hour, day- and night-time urinary cortisol and melatonin levels, and the effects of thyrotropin releasing hormone (TRH) on thyrotropin (TSH) and prolactin (PRL) secretions were studied in the same subjects. The data were correlated to the scores obtained by the Hamilton Rating Scale for depression and compared to those found in healthy subjects. Increased cortisol levels and the lack of DXT suppression of cortisol secretion are considered to be alcohol-dependent inasmuch as they disappear in most patients after alcohol withdrawal. The cortisol response to ACTH 1-24 infusion measured before and after alcohol withdrawal was similar in the patients we studied; moreover no significant difference was found between patients and controls. The increment of urine free cortisol levels in active alcoholics was not statistically significant. Urine cortisol levels became similar to those of the control subjects after alcohol withdrawal. The increased diurnal values of urine melatonin and the inversion of the physiological ratio between nocturnal and diurnal levels observed during alcohol intake became normal upon alcohol withdrawal. The TSH and PRL responses after the administration of 50 or 200 micrograms TRH were higher in alcoholics than in controls, while a blunted response is known to occur in depression.

[Early ECG changes after experimental focal cerebral ischemia. A pathogenetic hypothesis of the brain-heart syndrome]

Primary CVT alterations and arrhythmias, occurring one hour after embolization were detected in several experiments about focal cerebral ischaemia in rabbits. 62 animals were fed on a standard diet and 15 on an atherogenic diet. Primary CVT alterations and arrhythmias occurred in 4 rabbits fed on a standard diet and in 6 rabbits fed on an atherogenic diet. These results gave statistic evidence of a relationship between more frequent and serious electrocardiographic alterations and an atherogenic diet. The information coming out of these experiments are discussed. Considering the data coming out of other experiments and the data of the literature it is supposed that the pathogenesis of "the cerebro-cardiac syndrome" is linked to several biohumoral alterations occurring after the stroke. If these alterations occur in animals (or in subjects) with damaged coronary arteries cardiac alterations occurring after the stroke are greater and more important than the cardiac alterations occurring in the same conditions in the animals in which coronary arteries are not jet damaged.

Effects of remoxipride, a dopamine D-2 antagonist antipsychotic, on sleep-waking patterns and EEG activity in rats and rabbits

The antipsychotic remoxipride, a selective dopamine D-2 receptor antagonist, was studied for its effects on sleep-waking patterns in the rat and electroencephalographic (EEG) activity in the rabbit. Haloperidol, which has lesser selectivity for D-2 receptors, was used for comparison. In the rat, remoxipride (1-10 mg/kg SC) did not affect either total sleep or non-rapid eye movement (non-REM) sleep. Only REM was slightly reduced by the high dose of 10 mg/kg. Haloperidol (0.1-1 mg/kg PO) enhanced duration of both total sleep and non-REM sleep. In the rabbit, remoxipride (3 and 10 mg/kg IV) induced no significant changes of the EEG power spectrum over 0.1-38.5 Hz or individual frequency bands. In both cortex and hippocampus the drug did not alter the arousal response to acoustic sensory stimuli. Plasma concentration of remoxipride 10 mg/kg IV in rabbits declined biexponentially and was 4 and 2 mumol/l at 30 min and 1 h, respectively. Haloperidol (0.3 and 1 mg/kg) slowed down the EEG activity, enhanced the power spectrum of the cortical and hippocampal activity, and significantly reduced the duration of arousal induced by sensory stimuli. The results indicate that, unlike haloperidol, remoxipride has weak or no sedative effects. The data also provide support to the notion that D-2 receptors are not involved in the regulation of states of sleep and sedation.

Urine melatonin in alcoholic patients: a marker of alcohol abuse?

Ethanol is known to alter central neurotransmission and endocrine functions. Urine melatonin was studied in 10 male chronic alcoholic patients, before and after two weeks of controlled alcohol abstinence, and in sex and age matched healthy controls. In both groups, 24-hour urines were collected in two fractions corresponding to day- (D) (08:00-20:00) and night- (N) (20:00-08:00) time. Urine melatonin was assayed by RIA after methylene chloride extraction. Twenty-four hour urine melatonin levels were calculated adding up D and N values. In patients during alcohol intake, the 24-hour urine melatonin levels were significantly higher than in controls (p = 0.004, Student's t test). A disruption of the physiological ratio between N and D values was also observed, since the higher melatonin levels occurred in the D fraction. In drinking alcoholics, melatonin D values were significantly higher than the D values found in controls (p less than 0.01, Student's t test) and in the same patients after alcohol withdrawal (p less than 0.05). The N/D ratio approximated 1 during alcohol intake and became larger than 1 after alcohol withdrawal, as in the controls. The melatonin data were correlated with the suppressive effects of dexamethasone (DXT) on cortisol secretion evaluated both during alcohol intake and during abstinence. After alcohol withdrawal, the two (out of 10) patients, who remained unresponsive to the DXT suppression test, showed high D melatonin values and a low N/D ratio. These preliminary data indicate that in chronic alcoholism the pattern of urinary "melatonin- like immunoreactivity" is altered.

Anticonvulsive efficacy of flumazenil in the electroinduced seizures in the rabbit

The anticonvulsive efficacy of flumazenil, a specific antagonist of the ligands of the benzodiazepine receptor, was studied in the experimental seizures induced by electrical stimulation of corpus Amygdaloideum and Cornu Ammonis dorsale of the hippocampus in rabbits. In the amygdaloid seizure model flumazenil raised the threshold and/or reduced the afterdischarge duration. Results observed in the seizures induced by stimulation of hippocampus were less consistent. Possible explanations are discussed.

Evoked potentials monitoring of a cerebral focal ischemia model

A model of cerebral ischemia by microsphere embolization in the rabbit was monitored with somatosensory evoked potentials by median nerve stimulation (SEPs) and by flash visual evoked potential (VEPs). The degree of SEP alterations paralleled the type of lesions (focal or multifocal ischemia or diffuse oedema). Alterations present at the first hour after ischemia were generally unchanged during the follow-up, which ended at the 24th hour. The prevalence of VEP alterations was low (only 16% in focal ischemia). These results are compared to EEG modifications performed in the same animals.

The brain-heart syndrome: remarks on early ecgraphic changes following focal cerebral ischemia in healthy and in experimentally hyperdyslipidemic rabbits

Early cardiac effects of focal cerebral ischemia in two groups of rabbit, one of which made hyperdyslipidemic with an atherogenic diet, were detected in several experiments. In the group of 62 animals fed on a standard diet, primary CVT alterations and arrhythmias occurred in 4 rabbits (6.4%), in the group of 15 animals fed on an atherogenic diet the same cardiac alterations occurred in 6 rabbits (40%). A marked statistically significant prevalence of ECGraphic changes was observed in hyperdyslipidemic group. These results and the data coming out of other experiments and literature suggest that the pathogenesis of the "cerebro-cardiac syndrome" is linked to several biohumoral alterations occurring after the stroke. If these events affect functionally damaged endothelia, or occur in the presence of atherosclerotic plaques, cardiac alterations occurring after the stroke are greater than cardiac alterations observed in the same condition when coronary are intact or little damaged.

Neuropathological evaluation of brain damage in a rabbit model of focal cerebral ischaemia

In the present paper we studied different methods for a qualitative and quantitative morphologic assessment of the focal brain damage in rabbits after occlusion of the middle cerebral artery with vaseline microspheres. The study of the early brain ischaemic damage (4 to 12 hours after embolisation) was performed on serial coronal cryostat sections of hemispheres frozen in liquid nitrogen and processed for NADH enzyme-histochemical method. In the ischaemic area the necrotic cells were pale or negative after enzyme-histochemical reaction, but a quantitative assessment of the ischaemic area was approximative. The Evans blue method for the identification of the region of the edema at 24 hours after embolisation showed inconstant results. A reproducible method for a quantitative assessment of the ischaemic area up to the 24th hour after embolisation was proposed by Osborne and utilised in the present experimental conditions. The volumetric assessment of the ischaemic area was obtained after delineation of brain damage areas at 8 preselected coronal levels with a computerized automatic image analyzer and by integration of areas with the distance between each level. In treated animals, the measures of the volume of cerebral infarction were accurate and reproducible, and were suitable for neurophysiologic correlations.

Blood hypercoagulability secondary to experimental cerebral ischemia in the rabbit: influence of a hyperdyslipemia induced by an atherogenic diet

Within the framework of a research carried out at the Neurological Institute of Pavia on experimental cerebral ischemia some biohumoral determinations were done on two groups of rabbits: one kept on a standard diet and the other on an atherogenic diet to induce dyslipemia. The aim was to find out whether induced ischemia produces an activation of the hemocoagulation processes and whether hyperdyslipemia constitutes an aggravating factor. In the animals on a standard diet there was a statistically significant increase in factor X A and a nonsignificant increase in parameter (r + k) on TEG (thromboelastogram) and of factor VIII C after embolization. In the hyperdyslipemic group the changes were definitely more marked and, in the case of factor VIII C and parameter (r + k), statistically significant, accompanied by slight variations in APTT and factor IX pointing in the same direction. We discuss the meaning of our findings.

EEG changes and platelet aggregation in experimental cerebral focal ischemia in rabbits

Nine white New Zealand rabbits were submitted to internal carotid embolization with microspheres which caused a histologically verified focal cerebral ischemia. Six animals were sham-operated. EEG, QEEG, ECG, blood pressure, rectal temperature and platelet aggregation were monitored in basal conditions and one hour after ischemia. Embolized animals showed an increase in power density spectrum (PDS) and delta activity (0.15-3.70 Hz) and the appearance of platelet aggregation. The QEEG changes were correlated to the degree of platelet aggregation after ischemia.

Antagonism of EEGraphic and behavioural effects of methamphetamine by selective receptor blockers (SCH 23390 and raclopride) in the rabbit

1. The interactions between selective D1 and D2 antagonists (SCH 23390 and raclopride) and methamphetamine on EEG arousal and behaviour was studied in rabbits. Haloperidol, a "classic neuroleptic" was used as reference drug. 2. Both 23390 and raclopride, which were used at low dosage (0.03-0.09 mg/kg i.v. for the former and 1-3 mg/kg for the latter), were able to block completely the behaviour induced but do not inhibit completely the EEG arousal pattern induced by methamphetamine. 3. The blockade of both behaviour and EEG arousal took only when the two drugs were administered concomitantly at the lower dosage. 4. The antagonistic effects obtained with the concomitantly administration of the two drugs were of higher degree in confront of those obtained with the pretreatment with haloperidol 0.3 mg/kg i.v. 5. Our data indicate that both D1 and D2 antagonists are able to block, at the dosage used, motor hyperactivity and stereotyped behaviour typically induced by methamphetamine and that SCH 23390 and raclopride are potentiated also in this experimental model.