Changes in amine oxidase in plasma of rats treated with hepatotoxins

When allyl formate (AF) was administered to rats, the marked elevation of B-form MAO activity in plasma was found with beta-PEA as a substrate. In contrast, in the case of carbon tetrachloride (CCl4), A-form MAO activity elevated predominantly. The deaminations of 5-HT and beta-PEA in these plasma treated with AF or CCl4 were not inhibited completely by a high concentration of MAO inhibitor, deprenyl or clorgyline. These results indicate that there may be two or more distinct amine oxidases released from the liver and other organs in response to CCl4 or AF.

Reversible inhibition of aromatic hydroxylation of methamphetamine in rat liver microsomal preparations pretreated with methamphetamine

The effects of a single and repeated administration of methamphetamine (MP) in vivo in rats on its own metabolism in vitro were investigated. In both cases, the p-hydroxylation of MP to p-hydroxymethamphetamine by a microsomal fraction from rat liver was inhibited for a period of 16 hr after the last injection of MP. This inhibition was diminished by dialysis of the microsomal preparations. In contrast, the reduced level of cytochrome P-450 in hepatic microsomes from rats pretreated with the SKF 525-A did not revert to the control value after dialysis. When microsomes were preincubated with N-hydroxymethamphetamine, which is the metabolite of MP and a potent substrate for the formation of a metabolic intermediate (MI) complex with cytochrome P-450, the content of the MI was increased and the MP-hydroxylation activity decreased in direct proportion to the length of the preincubation. These results suggest that the inhibition of MP-hydroxylation may be due to reduction of the level of cytochrome P-450 that accompanies the formation of the MI complex. Furthermore, it appears that the complex can be dissociated by dialysis.

Changes in MAO activities in several organs of rats after administration of l-thyroxine

Male rats were given daily injections of 200 micrograms/kg l-thyroxine, s.c., for a period of 10 days. Monoamine oxidase (MAO) activities in the heart, lung and liver mitochondria decreased rapidly to about 50% those of the control rats with 5-HT and beta-phenylethylamine (beta-PEA) as substrates on the first day. After that, heart MAO activity increased gradually and exceeded the control value after 10 days with 5-HT as the substrate. The level of liver MAO activity was maintained at about 50-70% during the same period of administration with 5-HT as the substrate. The thyroxine treated rats showed no marked change in brain MAO activity. In vitro, l-thyroxine and its metabolites had no discriminative actions on MAO activities in these organs of rats. The heart, lung and liver MAO have unaltered Km values for 5-HT and beta-PEA, but decreases in the Vmax for both substrates were observed between the control and l-thyroxine-treated rats. Addition of the brain, heart and liver cytosol fractions from l-thyroxine treated rats caused MAO activities of heart mitochondria to decrease with 5-HT as a substrate and caused them to increase with beta-PEA as a substrate. MAO activities in liver also were inhibited by adding all the cytosols when beta-PEA was the substrate, but on the contrary, lung MAO activities were increased when 5-HT was the substrate. These results indicate the possible presence of multiple modulators of MAO in the cytosol fractions of l-thyroxine treated rats.

Effects of d-methamphetamine on monkey brain monoamine oxidase, in vivo and in vitro

A and B form MAO activities in mitochondria and synaptosome were measured in the brain of monkeys administered d-methamphetamine (d-MP) 2 mg/kg, i.m., daily for 7 days. When mitochondria were used as an enzyme preparation, the Km and Vmax values decreased with 5-HT (serotonin for A-form MAO substrate) and beta-phenylethylamine (beta-PEA for B-form MAO substrate), while in the synaptosome, a significant increase of the Km and Vmax values was observed with 5-HT and dopamine as substrates. The mitochondrial MAO treated with d-MP was inhibited strongly by clorgyline and deprenyl with beta-PEA as a substrate, while synaptosomal MAO was highly sensitive to these MAO inhibitors with 5-HT as a substrate. MP and amphetamine (AP) were found in brain mitochondrial and synaptosomal preparations of monkeys administered 2 mg/kg d-MP, i.m. daily for 7 days; MP and AP contents were 5.05 +/- 0.22 pg/mg protein and 37.3 +/- 3.8 ng/mg protein in mitochondria and 2.35 +/- 0.35 pg/mg protein and 46.4 +/- 1.5 ng/mg protein in synaptosomes, respectively. MAO was inhibited by MP and its metabolites, AP p-hydroxymethamphetamine (OH-MP) and p-hydroxyamphetamine (OH-AP), with 5-HT, beta-PEA and dopamine as substrates, in vitro. MP and its metabolites were more potent inhibitors of A-form MAO than B-form MAO.

[Electrophoretic properties of mitochondrial monoamine oxidase in monkey liver]

Monkey liver monoamine oxidase (MAO) was predominantly the B-form enzyme from the observed differences in substrate specificities and differences in sensitivities to MAO inhibitors. It is known that a MAO inhibitor, pargyline, binds to MAO irreversibly in the molar ratio of 1:1. 3H-pargyline was used as a marker to determine the existence of MAO. The molecular weight of MAO in monkey liver mitochondria was investigated by SDS-polyacrylamide gel electrophoresis after solubilization of 3H-pargyline binding mitochondria with 6% sodium dodecyl sulphate (SDS). The subunit molecular weight was found to be 60,000. The molecular weight determined from the electrophoretic mobility on several concentrations of gels by disc gel electrophoresis in the absence of SDS was found to be 120,000. These results indicate that monkey liver mitochondrial MAO exists as a dimer. Isoelectric focusing of the enzyme after solubilization with 0.1% Triton X-100 and 0.75% Triton X-100 and 0.75% Lubrol showed that it had a pI value near 6.5. Similar pI values were obtained for enzyme preparations solubilized with 0.75% Triton X-100 after treatment with phospholipase A or methylethylketone. These results suggest that the pI value of MAO in monkey liver mitochondria does not depend on the properties of detergents used to solubilize the enzyme preparation.

Evidence for existence of A and B form monoamine oxidase in mitochondria from dog platelets

It is known that platelet MAO appears to behave more like the B-form enzyme than the A-form enzyme based on inhibitor sensitivity and substrate specificity. However, dog platelets showed a different substrate specificity such as high activity with 5-HT and beta-PEA as substrates. Moreover, dog platelet MAO was sensitive to the drugs clorgyline and harmaline with 5-HT as the substrate, while it was sensitive to the drug deprenyl with beta-PEA as the substrate. These results also indicate the existence of two forms of MAO in dog platelets unlike in other platelets such as those from humans. A-form MAO from dog platelets was more stable against heat treatment at 55 degrees C than A-form MAO from dog liver and brain. On the other hand, there was no difference in the heat resistance of the three enzymes with beta-PEA as the substrate. After digestion with trypsin at 37 degrees C for 30 min, it was found that MAO from dog platelets, brain and liver were mostly inhibited with 5-HT as the substrate. In contrast, MAO in brain and liver were inhibited about 10%, but platelet MAO was inhibited about 50% with beta-PEA as the substrate. From these results, it is considered that dog platelet MAO exists as the two forms of the enzyme and has different enzymic properties in comparison with those of MAO from dog liver and brain mitochondria.

Modulation of neuronal MAO activity, 5-HT uptake and imipramine binding by endogenous substances in dog cerebrospinal fluid

Addition of small amounts of dog cerebrospinal fluid (CSF) inhibited both type A and type B monoamine oxidase (MAO) in dog brain mitochondria. The inhibition was competitive with 5-HT as substrate, but non-competitive with beta-phenylethylamine as substrate. Tricyclic antidepressants also exhibited competitive inhibition with type A MAO, but were non-competitive with type B MAO. The endogenous materials in CSF activate [3H]-imipramine specific, dose-dependent binding in dog brain preparations. The maximum number of binding sites (Bmax) increased, but the dissociation constant (Kd) was altered significantly in the presence of CSF. Addition of CSF induced a marked activation of uncompetitive [14C]-5-HT uptake in dog brain preparations. Moreover, there were reversibilities of the inhibition of MAO activity or of the activation of imipramine binding and 5-HT uptake by CSF substance after dilution experiment. These results indicate the possible presence of an endogenous psychotic drug-like substance in CSF.

Ossification of the posterior longitudinal ligament: a clinico-radiological study of 74 cases

A clinico-radiological analysis of 74 cases of ossification of the posterior longitudinal ligament is reported. Eighteen cases (24%) were asymptomatic or only had neck or shoulder pain; 16 cases (22%) showed signs of radiculopathy, and the remaining 40 cases (54%) had myelopathy. Ossification of the posterior longitudinal ligament developed most frequently at C5, and was rare in thoracic and lumbar regions. Ossification of the posterior longitudinal ligament led to stenosis of the spinal canal; more marked stenosis caused clinical myelopathy. The data showed that 30% of stenosis caused by ossification of the posterior longitudinal ligament was critical for the production of myelopathy.

Demonstration of endogenous inhibitors of monoamine oxidase in dog cerebrospinal fluid

Cerebrospinal fluid (CSF) from dogs competitively inhibited A-form MAO, but was non-competitive with B-form MAO. Heat treatment of CSF (90 degrees C, 20 min) had no effect on the inhibition. Digestion with trypsin and chymotrypsin reduced the MAO inhibitory activity. After ultrafiltration of the CSF through a membrane to remove substances of greater than 5,000 M.W., significant inhibitory activity persisted. These results suggest that CSF contains endogenous substances that act like MAO inhibitor to inhibit A and B-form MAO, and these substances are peptides of less than 5,000 M.W.

Methamphetamine-induced behavioral alterations following repeated administration of methamphetamine

Repeated administration of a large dose of methamphetamine (MA) (25 mg/kg, i.p. twice daily for 4 days) to mice enhanced locomotor activity and decreased stereotyped behavior following a subsequent injection of MA. Simultaneous determinations of catecholamines revealed a depletion of brain dopamine. The moderate doses of haloperidol significantly enhanced MA-induced locomotor activity in mice. A significant enhancement of MA-induced locomotor activity was observed in the rats pretreated with 6-hydroxydopamine into the striatum, and this effect correlated negatively with the striatal dopamine level. These results suggest that hypofunction of striatal dopaminergic neuron systems induced by repeated administration of MA may be one of possible mechanisms of the enhancement of MA-induced locomotor activity due to the decrease of stereotyped behavior.

Metabolism of methamphetamine, amphetamine and p-hydroxymethamphetamine by rat-liver microsomal preparations in vitro

Methamphetamine N-demethylation and p-hydroxylation activities of rat liver were located mainly in the microsomal fraction. The Km values for methamphetamine and p-hydroxymethamphetamine demethylations were 1.0 and 1.6 mM, respectively. The Km value for amphetamine p-hydroxylation was 10.2 microM; substrate inhibition occurred at high substrate concn. Two Km values were obtained for the aromatic hydroxylation of methamphetamine (10.6 microM and 2.2 mM). N-Demethylation of methamphetamine and p-hydroxymethamphetamine were depressed in rats pretreated with 3-methylcholanthrene, CoCl2 or SKF 525-A. In rats pretreated with phenobarbital, methamphetamine demethylase was induced and p-hydroxymethamphetamine demethylase was depressed. The p-hydroxylation of methamphetamine and amphetamine in rats pretreated with phenobarbital, CoCl2, SKF 525-A or iprindole were depressed.

Histochemical localization of monoamine oxidase in whole-body, freeze-dried sections of mice

Monoamine oxidase was investigated histochemically in tissues of the mouse by incubating freeze-dried, whole-body sections with tryptamine, serotonin, tyramine, beta-phenylethylamine, or benzylamine as substrate and Nitroblue tetrazolium as the final electron acceptor. The most intense staining with tryptamine was exhibited by intestinal epithelium and adrenal cortex; moderate staining was noted in the epithelium of the nose, bronchi, oesophagus, and upper stomach and in preputial gland, pancreas, nerve, spinal cord and brain. Weak staining was seen in the lung, spleen, liver and kidney. The distribution of the formazan deposition was similar, but much less intense, when serotonin and tyramine were used as the substrates. Only very weak staining was observed when beta-phenylethylamine was the substrate; no staining was seen with benzylamine. Monoamine oxidase activities with tryptamine were greatly inhibited by pretreatment with clorgyline (10 microM), while deprenyl (10 microM) slightly inhibited activities in all tissues except liver. This staining technique should be useful in further studies on the identification of the multiple forms of monoamine oxidase in tissues of the mouse. Nicotine and nitrosonornicotine were not substrates in any of the tissues; consequently, this enzyme system does not appear to produce the proximal carcinogen from this nitrosamine.

Histochemical localization of primary and secondary alcohol dehydrogenases in whole-body, freeze-dried sections of mice

Whole-body sagittal sections of frozen, C57BL/6J, adult, male mice were used for the localization of primary and secondary alcohol dehydrogenases in most tissues of the body. The reduction of Nitro BT with NAD+ as coenzyme, as described originally by Hardonk (1965), was utilized for the generation of coloured final reaction deposits. Ethanol was used as a substrate for primary alcohol dehydrogenase; 2-propanol, alpha-methylbenzyl alcohol and 2-butanol were used as substrates for secondary alcohol dehydrogenase. Liver and bronchial epithelium showed the highest activities for both enzymes; oesophageal and upper gastric epithelium showed a high activity of primary alcohol dehydrogenase. Pyrazole, indazole and imidazole inhibited primary, but not secondary, alcohol dehydrogenase. Dimethylsulphoxide and menthol slightly inhibited both enzymes. Oleic acid, sulphydryl agents, p-chloromercuribenzoate, and copper sulphate also inhibited both enzymes. Slight inhibition of secondary dehydrogenase was observed on co-administration of several alcohols. As expected, N-nitrosonornicotine did not function as a substrate for alcohol dehydrogenases. When this compound was present in the histochemical incubation media, no activity was seen at any of the usual sites of these enzymes. The distribution of the alcohol dehydrogenase activities found in this study correlates with the distribution of radioactivity in oesophagus, bronchi and liver after administration of [14C]nitrosonornicotine. This suggests that the alcohol dehydrogenases may be involved in the metabolism of hydroxylated nitrosonornicotine, a metabolite of the most abundant known carcinogen in cigarette smoke.

[A case of spinal epidural abscess in a renal transplant recipient]

A 44-year-old male underwent a cadaveric renal transplantation at the university hospital of Tsukuba on March 3, 1979. On June 11, 1979, he was discharged this hospital. Immunosuppressive therapy with azathioprine and methylprednisolone was done. On November 1, 1979, he developed back pain associated with fever. On November 3, 1979, he was admitted to the university hospital of Tsukuba. Laboratory study revealed leucocytosis. CRP inserum was positive. But pneumonia, urinary tract infection and infectious skin lesion were ruled out by physical, radiological and laboratory examination. On November 16, 1979, he became paraparetic. On the next day, he consulted the neurosurgical unit. Neurological findings were as follows: paraplegia, and hypesthesia and hypalgesia below the level of T4, and bilateral hyperrefrexia of P.T.R. and A.T.R. Lumbar myelogram revealed a complete block at the level T7. On November 17, 1979, a laminectomy from T4 through T7 was performed. The epidural abscess containing yellow pus was found and totally removed. Gram-positive rods were isolated on bacteriologic culture. On the 7th postoperative day, the sensory level dropped to L4 bilaterally and the muscle strength in the lower extremity became fair. About 3 years after operation, he became to be able to walk without cane. Discussion was made about this case together with previously reported cases.

Isoelectric focusing of isoenzymes of monkey brain monoamine oxidase

The multiple forms of monoamine oxidase (MAO) in monkey brain were investigated using an electrofocusing technique. When beta-phenylethylamine (beta-PEA) was used as substrate, two peaks (peak I and peak II) could be clearly distinguished from the profile; the isoelectric point (pI) values were near 7.8 and 6.3, respectively. When serotonin (5-HT) was used, MAO activity was observed in peak I enzyme. The peak I enzyme with a pI value of 7.8 contains AB-form MAO and oxidizes 5-HT and beta-PEA, while peak II enzyme with a pI value of 6.3 contains B-form MAO and oxidizes beta-PEA, respectively. However, when peak II enzyme was incubated in a pH 8.8 reaction medium, MAO activity toward 5-HT in peak II enzyme was seen.

Some interrelated properties of A and B form monoamine oxidase in monkey brain mitochondria

The multiplicity of monoamine oxidase (MAO) in monkey brain was studied by comparing the relationship between the selective substrates of MAO and the pH-activity curves obtained using these substrates. When mitochondrial and A-form MAO were used as the enzyme preparations with serotonin (5-HT) and norepinephrine (NE), preferential substrates for A-form MAO, the pH optima were 8.8 and 7.8 with 5-HT and 8.5 and 7.2 with NE. These substrates were also oxidized by B-form MAO after changing the pH of the incubation medium (shift to alkaline); these pH optima were 9.0 and 8.2, respectively. When common substrates of MAO were used (tyramine, octopamine, dopamine and tryptamine), the pH activity curves obtained were all broad and bell-shaped with pH optima for the 3 species of enzyme (mitochondria, A-form and B-form MAO) at 8.0, 7.8, and 8.0 with tyramine; 8.3, 7.5, and 8.5 with octopamine; 7.8, 7.5, and 8.5 with dopamine; and 8.0, 8.3, and 6.9 with tryptamine, respectively. The pH optima were 6.6 with beta-phenylethylamine (beta-PEA) and 9.0 with benzylamine, preferential substrates for B-form MAO, for either mitochondria or B-form MAO. The Km values obtained for tryptamine and beta-PEA were lower than those for the other substrates of MAO, regardless of the enzyme preparations. The Km and Vmax values of both forms MAO for 5-HT and NE were similar to those of the A-form MAO. The differences in the Km and Vmax values of the A-form MAO and B-form MAO for common substrates were comparable. Tyramine, octopamine and dopamine were substrates for both forms MAO, with only a slight preference for B-form MAO over A-form MAO. However, tryptamine may be deaminated predominantly by A-form MAO.

Use of evoked responses to measure laser photoradiation tissue effects

The amount of argon laser irradiation necessary to first produce marked changes in somatosensory evoked potentials when applied to the dorsal columns of cats was used to measure the enhancement of tissue response by fluorescein previously injected intravenously. The mean radiant exposure was roughly 2700 J/cm2 in normal control animals compared to a mean radiant exposure of only about 560 J/cm2 in animals given fluorescein. Thus, the presence of fluorescein in these tissues enhanced the laser's effectiveness by a factor of 5. We suggest the use of evoked responses as a measure of laser photobiological effectiveness.

Characteristics of mitochondrial and synaptosomal monoamine oxidase in monkey brain

Enzymic properties of monoamine oxidase (MAO) from monkey brain were studied. High MAO activity was observed in the mesencephalon and dienecephalon of the brain. Highest activity in every region of the brain was found with tyramine as a substrate. Monkey brain mitochondrial MAO showed a different substrate specificity and different Km and Vmax values than the enzyme from mice, rats, guinea pigs and rabbits. The pH activity curves were all bell-shaped, but the pH optima were remarkably different with the various substrates used. The activities of various substrates at pH 7.2 were compared with those at the pH optimum. At the pH optima, the activity was about 1.2-fold higher with tyramine and dopamine, 2-fold higher with beta-phenylethylamine (beta-PEA) and 3-fold higher with serotonin (5-HT) and benzylamine. These results were almost similar when synaptosomes from monkey brain were used. MAO activities with 5-HT and beta-PEA were strongly inhibited by much lower concentrations of clorgyline and deprenyl, respectively. Plateau-shaped inhibition curves by these inhibitors were obtained with tyramine as the substrate. These results indicate that both the A- and B-form of MAO appear to be uniformly distributed in monkey brain, and the A-form of MAO represents approximately 35% and 50% of the total MAO activity in mitochondria and synaptosomes, respectively.

Initial metabolism of gamma-hexachlorocyclohexane (gamma-HCH) by rat liver microsomes

gamma-Hexachlorocyclohexane (gamma-HCH) was metabolized by dehydrochlorination, dehydrogenation and dechlorination in rat liver microsomes and these initial metabolites of gamma-HCH were identified as gamma-pentachlorocyclohexene (gamma-PCCH), gamma-hexachlorocyclohexene (gamma-HCCH) and gamma-tetrachlorocyclohexene (gamma-TCCH) by gas chromatography-mass spectrometry (GC/MS). The dehydrochlorination and dehydrogenation were performed in incubation media containing NADPH and p,p'-tetramethyldiaminodiphenyl methane (TPD, 30 nmol) which is known to inhibit the degradation of initial metabolites formed during an aerobic incubation of gamma-HCH with microsomes at 25 degrees C. The dechlorination was found to proceed well under anaerobic conditions. The dehydrogenation was inhibited by SKF 525-A, CO, piperonyl butoxide, N2 and the absence of NADPH, but not by cyanide. Additionally, pretreatment of rats with phenobarbital (PB), but not with 3-methylcholanthrene (3-MC), induced the dehydrogenation of gamma-HCH. These results suggest that cytochrome P-450 is involved in this reaction. The cytochrome b5 system may not be involved. The dehydrochlorination was inhibited by N2, CO, piperonyl butoxide, KCN and the absence of NADPH, but not by SKF 525-A. This reaction was enhanced by pretreatment of rats with SKF 525-A, CoCl2 and piperonyl butoxide. Pretreatment with PB and 3-MC did not show a significant effect on the dehydrochlorination activity. Thus, the results suggest that the dehydrochlorination could be catalyzed by a specific species of cytochrome P-450 and cytochrome b5 system and/or other microsomal enzyme systems.

Effects of cephem antibiotics on rat liver aldehyde dehydrogenases

Effects of cephem antibiotics, which have a tetrazolethiol side chain, on rat liver mitochondrial aldehyde dehydrogenases (ALDH) were investigated in vitro and in vivo. The antibiotics tested were cefmetazole (CMZ), cefamandole (CMD), cefotiam (CTM), cefoperazone (CPZ) and latamoxef (LMOX). The antibiotics inhibited low-Km ALDH activity by 17-30% at 5 mM in vitro. The degrees of inhibition were in the order: CMZ = CTM = CMD greater than LMOX greater than CPZ. Disulfiram inhibited the enzyme activity by 50% at approx. 40 microM. The antibiotics (except CTM) at a dose of 1,000 mg/kg i.v. inhibited the low-Km ALDH activity by 36-52% of the control 24 hr after pretreatment, but did not alter the high-Km ALDH activity. The degrees of inhibition were in the order: LMOX = CMD greater than CPZ greater than CMZ. Disulfiram at a dose of 300 mg/kg p.o. markedly inhibited the low-Km ALDH activity, but did not alter the high-Km ALDH activity. The blood acetaldehyde levels during ethanol metabolism were elevated 1.3-2.6 times in rats treated with the cephem antibiotics (except CTM) for 24 hr at a dose of 1,000 mg/kg i.v. The degrees of elevation at 1 hr after ethanol injection were in the order: LMOX greater than CMD greater than CPZ greater than CMZ. The present experiments demonstrated that the rise in blood acetaldehyde levels coincided with the inhibition rates of the low-Km ALDH activity by the cephem antibiotics.

Comparative metabolism of fenitrothion and methylparathion in male rats

The mechanisms for the lower toxicity of fenitrothion as compared with methylparathion were investigated in male rats. The difference in the acute toxicity of the insecticides could be the more rapid decomposition of fenitrothion and fenitrooxon in rat liver than that of methylparathion and methylparaoxon. In particular, the decomposition of fenitrothion by hepatic microsomes was accelerated by increasing the insecticide concentration as the substrate. The oxygen analogues of both insecticides, fenitrooxon and methylparaoxon, were not detected in the brain after the administration of their parent compounds. From these results, it is concluded that the lower toxicity of fenitrothion as compared with methylparathion could be due to the greater rate of the decomposition of fenitrothion to its less toxic metabolites, rather than to the relative rate of penetration of the oxygen analogues into brain.

The relationship between conidial germination and esterase activities in Neurospora crassa

Esterase activity in rapidly germinating Neurospora conidia was several times higher than the esterase activity in conidia which germinate slowly. Starch gel electrophoresis experiments demonstrated the existence of esterase isoenzymes which are specific to the conidia. These isoenzymes completely disappeared during 20 h of conidial germination at 30 degrees C. Electron microscopy showed the successive breakdown of electron-dense compounds in storage bodies during conidial germination. These observations, taken together, indicate that the electron-dense compounds may be hydrolysed by specific esterases to serve as an endogenous energy and material source for germ tube formation. The levels of esterase activity, however, were not always proportional to the time required for conidial germination, indicating the possibility that additional enzyme systems might also be involved in the initial stages of germination.

[Basic research for visible laser unit for the spinal cord (a preliminary report)]

The cat's spinal dorsal column was irradiated unilaterally with Ar. laser of which power output was 500 mW and the spot size was 2 mm in diameter. The somatosensory evoked potentials (S.E.P.) were recorded bilaterally. In other cats, the fluorescein was injected intravenously for photoactivation and the dorsal column was irradiated with Ar. laser. The conclusion can be summarized as follows: 1) When the small demarcated area was made in the surface of the dorsal column by Ar. laser-irradiation, the early component of S.E.P. was disappeared. The histological finding revealed the destruction of the irradiated dorsal column. 2) The photoactivation effect of Ar. laser was demonstrated in the spinal cord, by using a fluorescein drug. The S.E.P. and the histological finding were the same as those of the nonfluorescein drug group. 3) The S.E.P. was available for the concept of the Laser-Photo-Biological-Effect (L.P.B.E.).

Ethylene oxide polyneuropathy

Sensorimotor polyneuropathy developed in two workers who had been exposed to ethylene oxide gas repeatedly for several months. Sural nerve biopsies revealed axonal degeneration with mild changes of the myelin sheath. Unmyelinated fibers were also involved. Muscle biopsies showed typical denervation atrophy. Symptoms improved after exposure to ethylene oxide terminated.

Effect of adrenalectomy, pretreatment with SKF 525-A, phenobarbital and diethyl maleate on the acute toxicity of fenitrothion in male rats

The effect of adrenalectomy (Adx), SKF 525-A, phenobarbital (PB), and diethyl maleate (DEM) on the acute toxicity of fenitrothion was investigated in male rats by assessing the degree of plasma cholinesterase activity. PB, 60 mg/kg/day for 3 days, exerted no protective effect on the toxicity of fenitrothion (100 mg/kg, p.o.) given 24 h after the last injection. In adrenalectomized and SKF 525-A-pretreated rats, the toxicity of fenitrothion was lower than that of the controls. Fenitrothion toxicity was increased by administration of DEM (1 ml/kg), which depletes hepatic glutathione (GSH) levels. In vitro, the rates of fenitrothion decomposition and fenitrooxon formation by microsomes were markedly affected by PB, SKF 525-A and Adx. The decomposition of fenitrooxon by the microsomal fraction and GSH-dependent decomposition of fenitrooxon by the soluble fraction were not affected by PB, SKF 525-A and Adx pretreatment. The GSH-dependent decomposition of fenitrothion and fenitrooxon was increased by addition of GSH to the incubation mixture. The present results indicate that the GSH-dependent metabolic pathway plays an important role in the detoxication of fenitrothion.

Methamphetamine-induced behavioral effects and releases of brain catecholamines and brain concentrations of methamphetamine in mice

The characteristic behavioral effect of methamphetamine (MA) at 2.5 mg/kg was enhanced locomotor activity which lasted over 2.5 hr. At 10.0 mg/kg MA, stereotyped behavior was predominant and lasted over 3 hr. The behavioral effect of 5.0 mg/kg MA was of the mixed type. MA at 5.0 and 10.0 mg/kg lowered the brain NE level from 2 hr after drug treatment, while the accumulation of MHPG-SO4 was increased over 2 hr at 2.5 and 5.0 mg/kg MA. The accumulation of HVA was significantly increased at 10.0 mg/kg MA over 3 hr. Accordingly, the behavioral effects of MA at the earlier period were compatible with the biochemical effects of MA. The behavioral effects during the 2- to 4-hr period, however, seem to be unrelated to the actions on brain catecholamines. Measurement of brain MA concentrations revealed that approx. 2 micrograms/g in the brain may be necessary to produce enhanced locomotor activity and the increased accumulation of brain MHPG-SO4. It appeared that approx. 8 to 9 micrograms/g MA in the brain was required to produce characteristic stereotyped behavior and the increased accumulation of HVA. Therefore, the behavioral and biochemical effects of MA were correlated with the brain MA concentrations.

Reduction of exogenous cytochrome c by Neurospora crassa conidia: effects of superoxide dismutase and blue light

The reduction of externally added cytochrome c by Neurospora crassa conidia was observed. The reduction was stimulated by antimycin A and suppressed partially by superoxide dismutase. When conidia were treated with diethyldithiocarbamate, which inactivated endogenous superoxide dismutase, the cytochrome c reduction was stimulated. Blue light also stimulated the cytochrome c reduction. Azide, which inhibits photochemical reactions mediated by flavins, suppressed the blue light effect. Superoxide dismutase partially suppressed the cytochrome c reduction in the light. The results suggest that O2(-) participates in the cytochrome c reduction by conidia and the flavins or flavoproteins are candidates for the receptor pigment of blue light to stimulate the cytochrome c reduction. It was also suggested that the redox component(s), which could directly transfer its reducing equivalents to exogenous cytochrome c, was present at the surface of conidia.

Effects of ethanol on catecholamine levels and related enzyme activities in different brain regions of rats

The effects of ethanol on the contents of norepinephrine (NE) and dopamine (DA) and the activities of related enzymes in the various regions of rat brains with different doses and mode of administration of ethanol were investigated. In acute ethanol intoxication, steady-state levels of NE were not altered. Continuous ethanol intoxication, however, significantly reduced NE contents and tended to decrease the activity of dopamine-beta-hydroxylase in the hippocampus. The decrease in NE contents became more significant during ethanol withdrawal, especially in the medulla oblongata and the striatum. DA contents were increased in the brain-stem region in all ethanol-treated rats. The increase in DA contents correlated with the increase in tyrosine hydroxylase activity. The present data suggest that the dopaminergic system may contribute to the development of physical dependence on ethanol.

Preferential inhibition of the B-form of monoamine oxidase in the liver of rats given 3'-methyl-4-dimethylaminoazobenzene in the diet

A and B-form monoamine oxidase (MAO) activities were measured in the liver of rats maintained with a diet containing 0.06% 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB). A-form MAO activity was similar to the control value throughout the feeding periods with serotonin as substrate. In contrast, B-form MAO activity decreased rapidly and the level of MAO activity was maintained at about 30% with beta-phenylethylamine (beta-PEA) as substrate. 3'-Me-DAB feeding did not cause any changes in MAO activity in the brain of rats. A single administration of 3'-Me-DAB (100 mg/kg p.o.) failed to alter A and B-form MAO activities for up to 4 days after its administration. The mechanism of inhibition of B-form MAO activity in rat liver mitochondria by 3'-Me-DAB was investigated. The inhibition of 3'-Me-DAB of B-form MAO activity, in vitro, was competitive and reversible. There was no difference in the apparent Michaelis constant toward beta-PEA between control and 3'-Me-DAB fed rats. B-form MAO in rat liver mitochondria was titrated with (-)deprenyl; this compound is selective to and an irreversible inhibitor of B-form MAO. The content of B-form MAO in liver mitochondria of rats fed 3'-Me-DAB for 3 weeks was decreased to about 60% of the control level.

Increase of adrenal weight in rats by the repeated administration of fenitrothion

Adrenal weight and the concentration of corticosterone and glucose in plasma of male Wistar rats, dosed orally with fenitrothion (7.25 or 14.5 mg/kg/day) for 28 days were investigated. A significant increase in the relative weight of adrenals was observed 2 weeks after treatment commenced, but was preceded by an increase in plasma corticosterone and glucose levels, which reached a maximum within 7 days. These results indicate that the repeated administration of fenitrothion might produce changes in adrenal function in rats.

Inhibition of monoamine oxidase by 3'-methyl-4-dimethylamino azobenzene (3'-me-DAB) in rat liver mitochondria

Effects of 3'-Me-DAB on MAO in rat liver mitochondria, in vitro, were investigated. 3'-Me-DAB at a concentration of 1 x 10(-5) M inhibits MAO activity about 40%, and this inhibition recovered to the control value after dialysis overnight against 0.001 M phosphate buffer. MAO activity was inhibited in an apparently competitive fashion by 3'-Me-DAB. These results indicate that 3'-Me-DAB binds to mitochondrial MAO with a weak affinity in vitro. The Km value toward benzylamine was 220 microM using both the mitochondria from the liver of rats fed a basal diet and those from rats ingesting 3'-Me-DAB. The activity of these enzyme preparations did not revert after dialysis to the control values of rats fed a basal diet. The titration experiment of MAO by pargyline suggests that the decrease of MAO activity, in vitro, is mainly due to the decrease of active MAO molecules in these mitochondrial preparations from livers of rats ingesting 3'-Me-DAB.

Protective effects of diisopropyl 1, 3-dithiol-2-ylidene malonate (NKK-105) on liver injury by carbon tetrachloride (CCl4)

Effects of NKK-105 against lipid peroxidation of microsomes by CCl4 are investigated, in vitro. NKK-105 had no effect on microsomal lipid peroxidation. With the microsomal fraction was preincubated with NKK-105 before adding CCl4, the lipid peroxidation induced with CCl4 was almost prevented by NKK-105. Effects of NKK-105 administration on aminopyrine N-demethylase, cyt.b5, cyt.p-450 and lipid peroxidation in CCl4-induced liver damage were investigated, in vivo. NKK-105 had no effect on the activity of aminopyrine N-demethylase and the content of cyt.b5, cyt.p-450 and peroxide. The content of cyt.b5, cyt.p-450 and the activity of demethylase remarkably decreased with CCl4 administration, but the content of cyt.p-450 and the demethylase activity were restored about 75% of the control values and cyt.b5 content was completely restored with previous administration of NKK-105. The amount of peroxide in the microsomal fraction increased with CCl4 administration was restored to the control level with previous administration of NKK-105.

Comparison of the effect of an equimolar and low dose of fenitrothion and methylparathion on their own metabolism in rat liver

The effects of fenitrothion and methylparathion on the activities of cholinesterase and hepatic microsomal monooxygenases were investigated and compared following a single or repeated oral administration of an equimolar and low dose of the insecticides. The activities of cholinesterase in brain and plasma were inhibited equally by the repetitive administration of both insecticides. Aminopyrine N-demethylase activity and cyt.P-450 content were not affected under the same experimental conditions. However, methylparathion, when given repeatedly, inhibited the dearylation and desulfuration of it own. The results may indicate that low dose continuous exposure to methylparathion could cause the depression of its own metabolism in rat.

Further studies on the synthesis of A-form monoamine oxidase

The relation between precursors and restoration of A-form MAO activity in rat liver after administration of clorgyline to rats was investigated by measuring the rates of recovery of A-form MAO activity after treatment with the inhibitor. The half-lives of mitochondrial and microsomal A-form MAO were estimated as 3.5 and 2.0 days, respectively. MAO activity and the amount of MAO molecules were completely restored within 14 days. However the values attained did not exceed the control values in a period of 14 days. Clorgyline plus cycloheximide or chloramphenicol did not prevent the recovery of MAO activity in the microsomes, but did not delay the appearance of enzyme activity in the mitochondria. A and B-form-like MAO were also observed in the microsomal and supernatant fractions, with clorgyline as inhibitor. These results suggest that the microsomal enzyme is a precursor of the mitochondrial enzyme, that the levels of A-form and B-form MAO are regulated genetically, and that the two forms of MAO may be synthesized separately.

[Computed tomography in diagnosis and management of acute head injury--correlation between clinical symptoms and CT findings (author's transl)]

A series of 202 patients with acute head injuries was investigated in correlation with clinical signs and computed tomographical findings. Clinical signs were classified into four types according to ARAKI's grading. Ninety three cases of type I, 61 cases of type II, 41 cases of type III and 7 cases of type IV were included in this series. The youngest patient was 40 days old and the oldest was 83 years old and average age was 31.3 years old. Initial C.T. was carried out in 70.80% of this series within 2 days after injury. Conclusions were obtained as follows: 1) Intracranial hemorrhages were recognized in 5.4% of type I, 18.0% of type II, 68.3% of type III and 100% of type IV on C.T. 2) All of intracranial hemorrhage in type I and type II were small and limited ones and showed no mass effect on C.T. 3) In all of severe cases with deep coma, their C.T. demonstrated poor visualization of so-called pentagone, ambient cistern and quadrigeminal cistern. These findings especially that of quadrigeminal cistern image were considered to be signs of poor prognosis. 4) Incidence of visualization of Sylvian fissure decreased in order of type I, type II, type III and type IV on C.T. Poor visualization of Sylvian fissure may reflect of small lesion in or out of cortex near Sylvian fissure such as small intracerebral hemorrhage, localized brain edema, small epidural hematoma etc. 5) Incidence of visualization of sulci decreased in order of type I, type II, type III, and type IV. Poor visualization of sulci may reflect existence of small lesion in or out of cortex in vertex area. 6) False negative of false positive finding on C.T. can result from slice level or time of C.T. and/or age of patient. Repeated C.T. may be recommended when the patient has conflicting neurological signs for these C.T. findings.

[A case with giant aneurysm of distal portion of the posterior inferior cerebellar artery (author's transl)]

A case of a giant aneurysm of the distal posterior inferior cerebellar artery has been presented, in which the preoperative sympotoms were those of a space occupying lesion of the posterior fossa. CT scan revealed a round mass in the cerebellum. The wall of this round mass was not enhanced after an intravenous administration of iodine. At operation we found a large saccular aneurysm, about 3 cm in diameter, arising from the distal portion of the left posterior inferior cerebellar artery. By needle decompression and dissection around the aneurysm, we were able to place a Heifetz clip across the neck. After exicision, the aneurysm was found to contain a large thrombus.

Inactivation of Neurospora crassa conidia by singlet molecular oxygen generated by a photosensitized reaction

Photodynamic damage of Neurospora crassa conidia was studied in the presence of the photosensitizing dye, toluidine blue O. Conidia which germinated to form colonies decreased in number as irradiation time became longer. The photoinactivation of conidia was suppressed by azide, bovine serum albumin, and histidine, and was stimulated in deuterium oxide. Wild-type conidia were less sensitive to the irradiation than albino conidia. In the wild-type, carotenoid-enriched conidia were more resistant against the lethal damage than the conidia which contained small amounts of carotenoids. These results suggest that singlet molecular oxygen causes photodynamic lethal damage to N. crassa conidia and that singlet molecular oxygen is quenched by endogenous carotenoids.

Giant aneurysm of the distal portion of the posterior inferior cerebellar artery

The authors report a case of a giant aneurysm of the distal portion of the posterior inferior cerebellar artery presenting the classical picture of a tumor of the posterior fossa. CT scan of a giant aneurysm reveals the clear margin and high density area of aneurysm wall, and the homogeneous and high density area of the organized thrombus in a cavity of the aneurysm.