Upregulation of brain somatostatin and neuropeptide Y following lidocaine-induced kindling in the rat

Male Sprague-Dawley rats received a daily injection of 60 mg/kg of lidocaine (> 30 days). Twenty percent of rats developed convulsions (kindled rats) and remaining rats did not show convulsions (non-kindled rats). The level of immunoreactive somatostatin (IR-SRIF) in kindled rats was significantly increased in amygdala than that in non-kindled rats and control rats. Immunoreactive neuropeptide Y (IR-NPY) contents in kindled rats were significantly increased in amygdala, hippocampus, cortex and striatum compared to non-kindled and control rats. The expression of SRIF mRNA in kindled rats produced a significant increase in amygdala, while NPY mRNA in kindled rats showed an elevated expression in both amygdala and hippocampus. These results coincide with the previous findings with the elevated expression of SRIF and NPY mRNA in electrically and pharmacologically kindled models, suggesting the important role of these peptides in the kindling phenomenon.

[A case of acute theophylline intoxication with repeated status convulsivus]

We report a 6-month-old female infant with status convulsivus which appeared during intravenous drip infusion of aminophylline. She had an extremely high serum theophylline concentration (79 micrograms/ml), which was effectively reduced by plasmapheresis and dialysis. Three days later, she developed status convulsivus again, though her serum theophylline was undetectable at that time. A CT on 14th day of illness revealed mild widening of frontal sulci and Sylvian fissure. The patient apparently recovered her healthy condition, but psychomotor developmental delay, especially in speech and social behavior, was noted at the age of 2 years 6 months (DQ = 55). A delay of myelination was observed on brain MRI at 4 year 1 months, suggesting an irreversible brain injury caused by theophylline intoxication.

Blood and cerebrospinal fluid pharmacokinetics of primidone and its primary pharmacologically active metabolites, phenobarbital and phenylethylmalonamide in the rat

Primidone is a clinically useful antiepileptic drug that is metabolised to two pharmacologically active metabolites phenobarbital and phenylethylmalonamide. As data on the inter-relationship between the systemic and central nervous system pharmacokinetics of primidone and its metabolites are sparse, we have investigated their temporal inter-relationship using a freely behaving rat model which allows repeated sampling of blood (100 microl) and cerebrospinal fluid (CSF; 20 microl). After administration, by intraperitoneal injection (50, 100 or 200 mg/kg), primidone rapidly appeared in both serum (Tmax mean range 1.5-2.5 h) and CSF (Tmax mean range 2.0-3.5 h), suggesting ready penetration of the blood-brain-barrier. This was also the case for phenylethylmalonamide and phenobarbital but peak concentration occurred later. Primidone, phenylethylmalonamide and phenobarbital concentrations rose linearly and dose-dependently in both serum and CSF. The mean free fraction (free/total concentration ratio) for primidone, phenylethylmalonamide and phenobarbital was 0.86, 0.97 and 0.88, respectively, and, as their respective mean CSF/serum ratio values were 0.73, 1.06 and 0.65, it would suggest that equilibration between the blood and CSF compartments is rapid. CSF mean t(1/2) values for primidone, phenylethylmalonamide and phenobarbital were similar to those of sera and essentially paralleled the pattern seen in sera.

Non-histone chromosomal proteins HMG1 and 2 enhance ligation reaction of DNA double-strand breaks

DNA ligase IV in a complex with XRCC4 is responsible for DNA end-joining in repair of DNA double-strand breaks (DSB) and V(D)J recombination. We found that non-histone chromosomal high mobility group (HMG) proteins 1 and 2 enhanced the ligation of linearized pUC119 DNA with DNA ligase IV from rat liver nuclear extract. Intra-molecular and inter-molecular ligations of cohesive-ended and blunt-ended DNA were markedly stimulated by HMG1 and 2. Recombinant HMG2-domain A, B, and (A + B) polypeptides were similarly, but non-identically, effective for the stimulation of DSB ligation reaction. Ligation of single-strand breaks (nicks) was only slightly activated by the HMG proteins. The DNA end-binding Ku protein singly or in combination with the catalytic component of DNA-dependent protein kinase (DNA-PK) as the DNA-PK holoenzyme was ineffective for the ligation of linearized pUC119 DNA. Although the stimulatory effect of HMG1 and 2 on ligation of DSB in vitro was not specific to DNA ligase IV, these results suggest that HMG1 and 2 are involved in the final ligation step in DNA end-joining processes of DSB repair and V(D)J recombination.

Effects of vinconate on age-related alterations in [3H]MK-801, [3H]glycine, sodium-dependent D-[3H]aspartate, [3H]FK-506 and [3H]PN200-110 binding in rats

We investigated the effects of age and (+/-)-methyl-3-ethyl-2,3,3a,4-tetrahydro-1 H-in-dolo[3,2,1-de] [1,5] naphthyridine-6-carboxylate hydrochloride (vinconate), an indolonaphthyridine derivative, on calcium channels, neurotransmitter receptor systems and immunophilin in Fischer rat brain using quantitative receptor autoradiography. [3H]MK-801, [3H]glycine, sodium-dependent D-[3H]aspartate, [3H]FK-506 and [3H]PN200-110 were used to label N-methyl-D-aspartate (NMDA) receptors, glycine receptors, excitatory amino acid transport sites, FK-506 binding proteins (FKBP) and voltage-dependent L-type calcium channels, respectively. [3H]Glycine and sodium-dependent D-[3H]aspartate binding significantly decreased in the frontal cortex, parietal cortex, striatum, nucleus accumbens, hippocampus, thalamus, substantia nigra and cerebellum of 24 month old rats in comparison with 6 month old animals. In contrast, [3H]MK-801, [3H]FK-506 and [3H]PN200-110 binding showed no significant changes in the brain of 24 month old rats. Intraperitoneal chronic treatment with vinconate (10 and 30 mg/kg, once a day for 4 weeks) dose-dependently ameliorated the significant reduction in [3H]glycine and sodium-dependent D-[3H]aspartate binding in the brain of 24 month old rats. These results demonstrate that glycine receptors and excitatory amino acid transport sites are more susceptible to aging processes than NMDA receptors, immunophilin and voltage-dependent L-type calcium channels. Furthermore, our findings suggest that vinconate may have a beneficial effect on age-related changes in glycine receptors and excitatory amino acid transport sites.

[Benign infantile mitochondrial myopathy caused by reversible cytochrome c oxidase deficiency]

A 2-month-old girl had generalized weakness, profound muscular hypotonia, hepatomegaly and severe lactic acidosis. She needed ventilatory support. Muscle specimen taken at 2 months showed ragged-red fibers, abnormal mitochondria, and reduced cytochrome c oxidase (CCO) staining Biochemical analysis showed CCO activity to be reduced to about 16% of the normal mean. She received carnitine and coenzyme Q10 supplementation from the age of 3 months and abnormal blood lactate values declined to near normal values during the first three weeks. Gradually her condition started to improved: she held her head at 9 months, and walked alone at 15 months. The second biopsy specimen at 3 years and 8 months showed almost normal CCO staining and she was free of clinical signs. This case is an example of a rare benign infantile mitochondrial myopathy caused by CCO deficiency. Early diagnosis is crucial to provide intensive treatment until spontaneous clinical improvement appears. We concluded that carnitine and coenzyme Q10 supplementation was a useful treatment for clinical improvement in patients with a benign infantile mitochondrial myopathy caused by CCO deficiency.

Vascular involvement in benign infantile mitochondrial myopathy caused by reversible cytochrome c oxidase deficiency

A 1-month-old Japanese girl had profound generalized weakness, hypotonia, and severe lactic acidosis. The infant improved gradually: she held her head at 9 months, learned to walk by 15 months. At the first muscle biopsy at 11 weeks of age, the specimen was characterized by numerous ragged-red fibers and decreased enzyme activity on cytochrome c oxidase (COX) staining. Electron microscopic findings were characterized by the presence of excessive abnormal mitochondria not only in skeletal muscle fibers but also in blood vessels. Vascular abnormalities consisted of an increased number of enlarged mitochondria in endothelial and smooth muscle cells of small arteries. Biochemical analysis showed an isolated defect of COX activity, which was only 16% of the mean control level. At the second biopsy at 44 months of age, the COX activity had increased to normal in the entire specimen. On electron microscopy, the abnormal mitochondria present on the first biopsy specimen had disappeared both in muscle fibers and blood vessels; nearly all mitochondria were morphologically normal at the second biopsy. Now at 5 years of age she can run and does not show muscle weakness. We report reversibility of abnormal mitochondria with age not only in skeletal muscle fibers but also in blood vessels in a patient, who had reversible COX deficiency with a benign clinical course.

A microdialysis study of glycinamide, glycine and other amino acid neurotransmitters in rat frontal cortex and hippocampus after the administration of milacemide, a glycine pro-drug

Milacemide is a glycinamide derivative which readily enters the brain and is metabolised to glycine. As its mechanism of action as an anticonvulsant drug is unknown we used the technique of microdialysis to study the temporal inter-relationship of glycinamide, glycine and other amino acid neurotransmitters in the extracellular fluid of rat hippocampus and frontal cortex. After milacemide administration (400 or 800 mg/kg i.p.), glycinamide concentrations rose linearly and dose-dependently in both hippocampus and frontal cortex. In contrast, whilst glycine concentrations rose in the hippocampus, glycine was unaffected in the frontal cortex. Concomitant increases in taurine hippocampal concentrations were observed. An increase in serine and a decrease in alanine concentrations was only observed at the highest milacemide dose (800 mg/kg). Other amino acids were affected. Thus, while glycinamide appears to be universally distributed throughout the brain, its metabolism to glycine and its effects on brain amino acids appear to be region specific.

The role of vasopressin, somatostatin and GABA in febrile convulsion in rat pups

In order to further elucidate a possible role of neuropeptides and GABA in the pathogenesis of febrile convulsions, we studied changes of immunoreactive-arginine vasopressin (IR-AVP), IR-somatostatin (IR-SRIF) and gamma-aminobutyric acid (GABA) in the rat brain after febrile convulsions induced by ultra-red light (UR). Male Wistar rats at 16 days of age irradiated with UR developed generalized convulsions after 4.9 +/- 0.5 min irradiation. Six rats were killed by microwave irradiation 3 min after UR irradiation prior to convulsion development, and 29 rats were killed either 0 min, 2 h, 6 h, 24 h or 48 h after febrile convulsions. Non-irradiated rats served as controls. The rat brain was dissected into 4 regions; amygdala, hypothalamus, cortex and hippocampus, and subjected to radioimmunoassays. IR-AVP levels in hypothalamus were increased 3 min after UR and decreased at 2 h and 6 h after the convulsions. IR-SRIF levels were increased in cortex and hippocampus at 3 min after UR and 0 min after the convulsions. The GABA content increased in all regions tested at 2 h and 6 h after the convulsions. These results suggest that AVP, SRIF and GABA may be involved in the pathogenesis of febrile convulsions in different ways.

[Inhibitory effect of AS-35. a novel antiallergic drug, on chemical mediator release from human eosinophils]

To determine whether AS-35, a new antiallergic drug, inhibits the activation of eosinophils, we examined the effect of AS-35 on the release of leukotriene C4 (LTC4) and eosinophil peroxidase (EPO) from human eosinophils. Calcium ionophore A23187 caused both LTC4 and EPO release from human eosinophils. AS-35 (1 x 10(-5) M) inhibited A23187-induced LTC4 release from the eosinophils with 56% inhibition. AS-35 (1 x 10(-6) to 1 x 10(-5) M) also inhibited A23187-induced EPO release from the eosinophils in a dose-dependent fashion with 79% inhibition at 1 x 10(-5) M. We concluded that AS-35 prevents the activation of human eosinophils to inhibit LTC4 and EPO release. These results suggest that AS-35 might be useful in controlling allergic diseases by inhibiting eosinophil activation.

Effects of anticonvulsants and gamma-aminobutyric acid (GABA)-mimetic drugs on immunoreactive somatostatin and GABA contents in the rat brain

Immunoreactive somatostatin (IR-SRIF) and gamma-aminobutyric acid (GABA) contents in the rat brain were investigated to study chronic effects of the treatment with anticonvulsants, carbamazepine (CBZ), valproic acid (VPA) and phenytoin (PHT). Decreased IR-SRIF levels were found in several brain regions after chronic treatment with VPA and CBZ. GABA concentrations were found to be increased significantly in chronic CBZ and VPA treatment in the rat brain, especially in limbic structures. PHT had no effect on both IR-SRIF and GABA contents in the rat brain. Effects of several GABA-mimetic drugs also were studied on IR-SRIF contents in the rat brain. Aminooxyacetic acid an inhibitor of GABA transaminase, induced a decrease in IR-SRIF concentration in the pyriform and entorhinal cortex, whereas ethanolamine-o-sulfate, another GABA-transaminase inhibitor and muscimol, a GABA receptor agonist had no effect on brain IR-SRIF after acute administration. The present results suggest that endogenous somatostatin has an important role for anticonvulsant properties of CBZ and VPA, but not of PHT. The relationship between the changes in IR-SRIF and the GABA transmitter system in the anticonvulsant action of CBZ and VPA remains to be clarified.

Clear cell carcinoma of the pancreas

A rare autopsy case of clear cell carcinoma of the pancreas developing in a 71-year-old Japanese male is described. He complained of epigastralgia and back pain and was clinically diagnosed as having primary pancreatic cancer. After death due to disseminated metastasis and cachexy, autopsy revealed pancreatic clear cell carcinoma metastasizing to various organs including the lungs (lymphoangiosis carcinomatosa). The tumor was almost entirely composed of clear cells with cytoplasm weakly positive for PAS and alcian blue, and negative for Sudan III stains. Histological differential diagnosis from the clear cell carcinoma of other organs, especially that of kidney, is also mentioned.

Effects of carbamazepine and valproic acid on brain immunoreactive somatostatin and gamma-aminobutyric acid in amygdaloid-kindled rats

Somatostatin and gamma-aminobutyric acid (GABA) concentrations were evaluated in the brain of kindled rats treated chronically with carbamazepine and valproic acid. Kindled seizures were almost completely blocked by treatment with carbamazepine, whereas the effect of valproic acid was partial, suppressing only generalized seizures. The duration of after-discharge in amygdala was suppressed by carbamazepine not by valproic acid. Carbamazepine induced a decrease in immunoreactive somatostatin concentration and an increase in GABA concentration in the temporal cortex of kindled rats. Valproic acid induced only an increase in GABA concentration. The results suggest that somatostatin may be associated with the suppression of focal seizure in amygdala and GABA may have a role in the suppression of generalized seizures.

Delta sleep-inducing peptide-like material in rat brain as determined by enzyme immunoassay: Effect of sleep deprivation

The regional distribution of immunoreactive delta sleep-inducing peptide (IR-DSIP) and the effect of 24-h sleep deprivation on the IR-DSIP content was investigated in the rat brain by means of enzyme immunoassay (EIA) of the assayable IR-DSIP in the rat brain coeluted with authentic DSIP in the gel filtration. It is thus suggested that the present EIA method preferentially detects fee DSIP and not bound DSIP. IR-DSIP proved to be more concentrated in the limbic structures, although the contents were generally at a low level. Sleep deprivation and subsequent rebound sleep had no significant effect on the brain contents of 'free-form' DSIP.