Regional differences in alpha1-adrenoceptor subtypes and mechanisms in rabbit arteries

Contractility mediated through alpha1-adrenoceptor subtypes and the maximum binding site (Bmax value) and the dissociation constant (Kd value) for [125I]HEAT ([125I]iodo-2-(beta-(4-hydroxyphenyl)ethylaminomethyl)tetralone) were determined in the following rabbit arteries: thoracic and abdominal aorta, mesenteric, renal and iliac arteries, and the alpha1-adrenoceptor subtypes mediating contractile mechanisms in vascular smooth muscle were studied. The pD2 values for norepinephrine differed considerably among the arteries in the presence of nicardipine (10(-5) M), while the pA2 values for 5-methylurapidil against norepinephrine were identical at low affinity in all the arteries used. In Ca2+-free physiological saline solution (Ca2+-free PSS), the pA2 values for 5-methylurapidil were also similar except for the renal artery, in which there were no stable contractions. In normal PSS, the concentration-response curves for norepinephrine with chloroethylclonidine-pretreatment were shifted to the right (pD2 values of 5.58, 5.70, 5.74, 5.98 and 6.38 for thoracic and abdominal aorta, mesenteric, renal and iliac arteries, respectively). In the [125I]HEAT binding study using membrane preparations obtained from chloroethylclonidine-treated strips, the Bmax values (33.2-105.2 fmol/mg protein) for [125I]HEAT varied considerably among arteries, while the Kd values (0.20-0.26 nM) were identical. The logarithm of Bmax values is proportional to the pD2 values for norepinephrine (slope=0.69, r=0.961). These observations suggest that the regional differences in potency (pD2 value) of the alpha1-adrenoceptor agonist, norepinephrine, are a result of the differences in population and density of alpha1-adrenoceptor subtypes in rabbit arteries.

Molecular cloning of Saccharomyces cerevisiae MLF4/SSH4 gene which confers the immunosuppressant leflunomide resistance

Immunosuppressant leflunomide inhibits the growth of cytokine-stimulated lymphoid cells in vitro and also inhibits the growth of eukaryotic microorganism Saccharomyces cerevisiae. To elucidate the molecular mechanism of the action of the drug, a yeast gene which suppresses the anti-proliferative effect when in increased copy number was cloned and designated MLF4 for multicopy suppressor of leflunomide sensitivity. DNA sequencing analysis indicates that the MLF4 gene is identical to the SSH4 gene which suppresses the shr3 mutation. Excess of amino acids overcame the anti-proliferative activity of leflunomide. Thus, leflunomide is suggested to affect amino acid transport by interacting with Shr3 chaperon-like protein.

IL-6-deficient mice are resistant to the induction of experimental autoimmune encephalomyelitis provoked by myelin oligodendrocyte glycoprotein

The role of IL-6 in experimental autoimmune encephalomyelitis (EAE) provoked by myelin oligodendrocyte glycoprotein (MOG) was investigated using IL-6-deficient mice. We show here that IL-6-deficient mice were resistant to the MOG-induced EAE as compared to wild-type mice (one out of 18 versus 17 out of 20). The delayed-type hypersensitivity response, lymphocyte proliferation response and antibody reactivity to MOG in IL-6-deficient mice were significantly lower than those in wild-type mice. Furthermore, the histological examination revealed that no infiltration of inflammatory cells was observed in the central nervous system of IL-6-deficient mice. These results indicate that IL-6 may play a crucial role in the induction phase of EAE. Given the potential relevance of this animal model for multiple sclerosis (MS), it is possible that anti-IL-6 therapy may be useful in the prevention of relapses of MS.

Fas has a crucial role in the progression of experimental autoimmune encephalomyelitis

To investigate the role of Fas in experimental autoimmune encephalomyelitis (EAE) in mice, we examined the susceptibility of EAE in C57BL/6 (B6).lpr mice lacking Fas. The frequency of myelin oligodendrocyte glycoprotein (MOG)-induced EAE in B6.lpr mice was significantly lower than that in B6 mice (19% vs 94%). However, no significant difference was observed between them in either the lymphocyte proliferation response or antibody reactivity to MOG. In addition, the histological examination and semiquantitative reverse transcriptase polymerase chain reaction analysis revealed that the infiltration of inflammatory cells and the up-regulation of gene expression for inflammatory cytokines occurred in the central nervous system (CNS) of B6.lpr mice immunized with MOG, even if they showed no clinical sign. These results indicate that Fas may contribute to the pathogenesis of EAE and may play a crucial role in the expansion of inflammation and/or myelin destruction in the CNS rather than in the activation of encephalitogenic T cells in the periphery and/or the breakdown of blood brain barrier.

Fabrication Technique of a Nonlinear Optical Structure Using Optical Polymeric Films by Direct Electron-beam Irradiation

A simple fabrication technique of nonlinear optical structures for use with dye-doped polymer is described. Polymethylmethacrylate, U-100 polymer, and polystyrene were used as the host matrices to fabricate the nonlinear optical waveguide. The periodically poled nonlinear optical polymer structures and ridge-type channel structures were fabricated by direct electron-beam irradiation. The electron beam with 25 kV of energy was exposed directly onto the polymer films containing the nonlinear optical chromophores. We can also demonstrate the fabrication technique of the domain-inverted grating of dye-doped polystyrene film.

Three novel missense mutations in unrelated Japanese patients with type I and type II protein S deficiency and venous thrombosis

A molecular analysis of protein S deficiency in three unrelated Japanese patients was performed. An approximately 50% reduction in both functional and immunologic levels of protein S was detected in the plasmas from two unrelated patients, designated protein S Osaka 1 and protein S Osaka 2. An approximately 50% reduction in the functional level, but a normal immunologic level of protein S, was detected in plasma from a third patient, designated protein S Osaka 3. All of the exons and exon/intron junctions of the protein S gene were studied using a strategy combining polymerase chain reaction amplification and rapid non-radioactive single-strand conformational polymorphism analysis. We identified a G-to-A change in exon X of the protein S gene in protein S Osaka 1. This mutation resulted in the substitution of Gly for Ser at position 295 in the sex hormone-binding globulin-like region. In protein S Osaka 2, a G-to-C change at the position of the 3' end of exon III was identified, leading to the amino acid substitution of Val46 by Leu in the aromatic stack region. In protein S Osaka 3, an A-to-G change in exon II was identified, leading to the substitution of Lys9 by Glu in the Gla domain. It was concluded that the Gly295-to-Ser mutation and Val46-to-Leu mutation cause type I protein S deficiency and that the Lys9-to-Glu mutation causes type II deficiency.

Severe motor-dominant neuropathy with IgM M-protein binding to the NeuAcalpha2-3Galbeta- moiety

We report the occurrence of a relapsing, severe predominantly motor neuropathy in a 75-year-old man with an IGM-K M-protein binding to gangliosides GM2, GM3, GM4, GD1a, GT1b and LM1. Motor nerve conduction velocities were slowed with conduction block. A superficial peroneal nerve biopsy specimen revealed segmental demyelination and remyelination. The patient improved after repeated plasma exchanges, and the antibody titer decreased in association with clinical recovery. This IgM M-protein has a unique, previously unreported binding specificity for terminal NeuAcalpha2-3Galbeta- moiety in common to all gangliosides bound by the antibody except GM2. M-proteins with this affinity may be involved in the pathogenesis of this and other cases of motor-dominant demyelinating neuropathy.

Mitochondrial abnormalities in a murine model of primary carnitine deficiency. Systemic pathology and trial of replacement therapy

Mitochondrial abnormalities and effectiveness of replacement therapy were examined in a murine model of systemic carnitine deficiency, namely the juvenile visceral steatosis (JVS) mouse. Homozygous JVS mice revealed severe lipid deposition and abnormal mitochondria in liver, heart, skeletal muscle, and kidney, but there was no pathological change in the nervous system, though they showed cerebral signs. There were numerous ragged-red fibers in muscles, but enzyme activities of the respiratory chain were intact. Histograms of oxidative and nonoxidative muscle fibers showed an increase in small and oxidative muscle fibers in 4-week-old JVS mice, but this difference no longer existed in 8-week- or 1-year-old JVS mice. On the contrary, Mn-superoxide dismutase immunostaining of muscle showed a focal increase in every age of JVS mice. With L-carnitine treatment, JVS mice could survive for a year, but to some extent, there were the same pathological changes as those seen in untreated mice.

The fluid-attenuated inversion-recovery pulse sequence in assessment of central nervous system involvement in myotonic dystrophy

We compared the fluid-attenuated inversion recovery (FLAIR) sequence with conventional spin-echo (SE) imaging for detection of involvement of the central nervous system in five patients with myotonic dystrophy (MD). The diagnosis was made based on clinical features and DNA analysis. All patients showed abnormal high-intensity lesions in the white matter on T2-weighted images, although these were more clearly visible using FLAIR.

Aminoguanidine, a selective inhibitor of the inducible nitric oxide synthase, has different effects on experimental allergic encephalomyelitis in the induction and progression phase

To elucidate the role of excessive nitric oxide (NO) via the inducible nitric oxide synthase (iNOS) in experimental allergic encephalomyelitis (EAE), the effect of a selective iNOS inhibitor, aminoguanidine, was investigated using mice with actively induced EAE. Administration of aminoguanidine by intraperitoneal or intracisternal injection from day 2 to day 12 after immunization produced a significant delay in the onset of EAE. On the other hand, administration of aminoguanidine by intraperitoneal or intracisternal injection for 10 days after the onset of EAE enhanced the clinical severity and mortality rate and hastened the onset of relapse significantly. The histological study at day 11 after the onset revealed that more inflammatory cells were present in the central nervous system of mice treated with aminoguanidine as compared with mice without aminoguanidine treatment. These results suggested that NO via iNOS was a pathogenetic factor in the induction phase of EAE, but had an inhibitory role in the progression phase of EAE. Although the effect of NO synthase inhibitors on EAE has been controversial, the present study suggested that the timing of administration might be an important consideration and might explain the previous contradictory reports.

A clinicopathological study of a patient with familial amyotrophic lateral sclerosis associated with a two base pair deletion in the copper/zinc superoxide dismutase (SOD1) gene

The recognition of mutations in the copper/zinc superoxide dismutase (SOD1) gene in familial amyotrophic lateral sclerosis (FALS) has been a landmark in ALS research. We report a clinicopathological study of a female patient with FALS showing a two base pair deletion in exon 5 of the SOD1 gene. Her clinical course was rapid and she died 2 years after the onset. The SOD1 activity was down to 30% of the normal level. Western blot analysis did not reveal the mutant protein which was expected to be approximately 2.4 kDa smaller than normal SOD1 protein in molecular mass. In contrast to the neuropathological findings of the previously reported cases showing the same mutation, our case was characterized by sparing of the dorsal column and the presence of only a modest number of intracytoplasmic eosinophilic inclusions showing weak or partial immunoreaction for neurofilament and negative reaction for SOD1. Thus, the same mutation in the SOD1 gene does not necessarily induce consistent pathological changes in the central nervous system.

Role of nitric oxide in the convulsive seizures induced by fluoroquinolones coadministered with 4-biphenyl acetic acid

1. Contribution of nitric oxide to the convulsive seizures induced by fluoroquinolones (FQs) coadministered with 4-biphenyl acetic acid (BPAA), the active metabolite of fenbufen, was assessed in mice. 2. Enoxacin + 4-biphenyl acetic acid caused clonic seizures in all treated mice, followed by tonic seizures and death. These events were associated with a significant increase in intracerebellar cyclic GMP. 3. Pretreatment with the nitric oxide synthase (NOS) inhibitor, NG-nitro-L-arginine methylester (L-NAME), but not with D-NAME, significantly reduced the incidence of convulsions and lethality, as well as the increase in cyclic GMP. 4. Pretreatment with N-methyl-D-aspartic acid (NMDA)-receptor antagonist, MK-801, inhibited only the transition of clonic seizure to tonic seizure without affecting the incidence of clonic seizure and lethality. 5. These findings suggest that FQs + BPAA exert convulsions by activating NOS partly through the mediation of the NMDA receptor in the brain cells.

Degeneration of the pyramidal tracts in patients with amyotrophic lateral sclerosis. A premortem and postmortem magnetic resonance imaging study

To investigate focal hyperintensity in the internal capsule (IC) on magnetic resonance images (MRIs) and its clinical significance, 80 patients with amyotrophic lateral sclerosis (ALS) and 80 sex- and age-matched normal control subjects were studied. On T2-weighted images, hyperintense foci were found in the posterior part of the posterior limb (PL) of the IC in 41 (51%) of 80 control subjects. However, no subject showed increased signal intensities on proton density-weighted images. Hyperintense foci were also observed in the posterior part of the PL of the IC on T2-weighted images in 52 (65%) of 80 ALS patients and on proton density-weighted images in 26 (65%) of 40 ALS patients; the abnormally intense foci were seen at the same anatomical location in the IC as those in the normal control subjects. On postmortem MRI, the abnormally intense foci were found in the posterior part of the PL of the IC in the formalin-fixed brains from 9 ALS patients. Three normal control subjects did not show signal intensity changes on postmortem MRI. On histological examination of 9 ALS brains, distinct myelin pallor and gliosis were found in the posterior third of the PL of the IC. Proton density-weighted images appear to be useful to distinguish neuropathological changes in the corticospinal tract of ALS patients.

Block of the cell cycle of the yeast Saccharomyces cerevisiae by tyrphostin, an inhibitor of protein tyrosine kinase

Tyrphostins are inhibitors of the epidermal growth factor receptor tyrosine kinase. To elucidate the biological function of protein tyrosine kinases in yeast cells, a mutant hypersensitive to tyrphostin was isolated and investigated for its response to the drug. The mutation was recessive and was designated tpt1 for tyrphostin hypersensitive. A tpt1 strain cannot grow in the presence of tyrphostin, implying that a biological process sensitive to tyrphostin is essential for cell growth. Microscopic observation indicated that large-budded cells were accumulated in the presence of the inhibitor. The results suggest the involvement of protein tyrosine phosphorylation in the cell cycle progression of Saccharomyces cerevisiae.

Demyelination in severe combined immunodeficient mice by intracisternal injection of cerebrospinal fluid cells from patients with multiple sclerosis: neuropathological investigation

Demyelinating lesions have been observed in severe combined immunodeficient (SCID) mice after intracisternal administration of cerebrospinal fluid cells (CSFC) from patients with multiple sclerosis (MS). Further investigation in our laboratory revealed that CSFC from 6 to 15 patients at exacerbation of MS caused demyelination. The factor leading to demyelination appears to be the high frequency of relapses during a short period, but not to the severity of the disease. Neuropathological and immunohistochemical studies revealed that a lack of inflammatory mononuclear cell infiltration within and around the demyelinating lesions or in leptomeninges was a common characteristic in all SCID mice with CSFC-induced demyelination. In affected mice killed 2-3 weeks after intracisternal administration of CSFC, foamy/vacuolar lesions with a small or moderate number of lipid-laden macrophages were seen in the white matter. Ultrastructurally, relative preservation of axons, in contrast to myelinoclastic features, as well as some remyelinated axons were observed. In affected SCID mice killed 4-6 weeks after intracisternal administration, more widespread foamy macrophages and necrotic foci with poor remyelination were seen. The findings were similar to those seen in experimental allergic encephalomyelitis, though without lymphocytic infiltration, but were quite different from the lesions observed in Theiler's murine encephalitis virus infection. The absence of an immunohistochemical reaction to the human leukocyte common antigen in the infiltrating mononuclear cells suggested that the graft-versus-host reaction was unlikely cause of the demyelinating lesions.

The effect of dexamethasone on the expression of activated NF-kappa B in adjuvant arthritis

The transcription factor NF-kappa B plays a significant role in inflammatory diseases. In this study we have investigated the expression of activated NF-kappa B p65 subunit in the rat adjuvant arthritis model in a 28-day time-course experiment using immunohistochemistry. The expression of p65 was detected in the synovial lining layer and around the blood vessels in the inflamed synovium as early as Day 3 post-adjuvant injection. The cells that expressed p65 in the synovial lining were thought to be macrophage-like synoviocytes. The expression was stronger in the injected hindpaw than that in the noninjected hindpaw. Dexamethasone treatment at 1 mg/kg p.o. (Days 0-20) suppressed both the hindpaw edema and increase in p65 expression. Withdrawal of the treatment caused increases in both p65 expression and paw volume. Together these suggest that activated NF-kappa B was specifically expressed in the arthritic synovium and may play a significant role in the development of arthritis.

Cognitive function in amyotrophic lateral sclerosis

Cognitive function in patients with amyotrophic lateral sclerosis (ALS) has drawn recent attention. However, the pathogenesis of cognitive dysfunction in patients with ALS remains uncertain. To explore the underlying mechanism for cognitive dysfunction further, we studied 26 patients with ALS (15 male and 11 female; age from 36 to 67 years) by using neuropsychological batteries, magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT). We also evaluated these patients and an additional 26 age- and sex-matched normal controls using neuropsychological batteries with special attention to the frontal lobe function. On the basis of neuropsychological examination, we classified patients into three groups using cluster analysis. Age, education level and severity were comparable across these subgroups. Neuropathologic examination was subsequently carried out in six patients. Patients in Group 1 and 2 had low scores on all measures compared to patients in Group 3 and normal controls. Patients in Group 1 and 2 had frontal atrophy on MRI and reduced isotope uptake in the frontal region on SPECT, which was more evident in patients in Group 1. On neuropathologic examination, patients in Group 1 showed spongy degeneration and neuronal loss in the frontal lobe. Patients in Group 3 showed no notable pathology in the frontal region. The gradient distribution of the scores for attention and executive function, as well as SPECT findings suggested the presence of a continuum of cognitive disability in patients with ALS corresponding to the pathologic process in the frontal lobe ranging from significant impairment to normality. We, therefore, believe that inattention and executive dysfunction alternatives may evolve in patients with ALS corresponding to the pathologic process in the frontal lobe.

Nitric oxide via an inducible isoform of nitric oxide synthase is a possible factor to eliminate inflammatory cells from the central nervous system of mice with experimental allergic encephalomyelitis

We recently identified the inducible isoform of nitric oxide synthase (iNOS) in inflammatory lesions of the central nervous system (CNS) in mice with experimental allergic encephalomyelitis (EAE), a known animal model of multiple sclerosis (MS). In the present study, the role of excessive nitric oxide (NO) production via iNOS was investigated in mice with EAE using immunohistochemistry with antibodies to nitrotyrosine and iNOS, NADPH-diaphorase histochemistry, and the in situ terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) method to detect cell death, presumably through an apoptotic mechanism. NADPH-diaphorase histochemistry and immunohistochemistry for iNOS revealed an elevation of nitric oxide synthase (NOS) activity during the course of EAE, which came from iNOS. Nitrotyrosine was detected in infiltrated cells and some glial cells in the spinal cord lesions, where iNOS-positive inflammatory cells were present at the peak of EAE. The findings implied the generation of NO and peroxynitrite in the EAE lesions, which might damage structural and functional proteins. The TUNEL positive cells were mainly inflammatory ones, and most of them were located in close proximity to iNOS-positive cells, while some of them were iNOS-positive themselves. These results suggested that excessive NO via iNOS played an important role to eliminate inflammatory cells in the CNS of mice with EAE, possibly through an apoptotic mechanism.

Quantitative RT-PCR for inhibin/activin subunits: measurements of rat hypothalamic and ovarian inhibin/activin subunit mRNAs during the estrous cycle

Inhibins (alpha-beta(A) and alpha-beta(B)) and activins (beta(A)-beta(A), beta(A)-beta(B) and beta(B)-beta(B)) were originally isolated from ovarian follicular fluids as FSH secretion modifiers. Inhibin/activin subunits, alpha, beta(A) and beta(B), are widely distributed in several tissues, including gonads and brain, and inhibins and activins have been reported to be involved in ovarian or hypothalamic functions. In this study, we established and employed a competitive RT-PCR assay system for rat inhibin/activin subunits by capillary electrophoresis to determine rat hypothalamic and ovarian inhibin/activin subunit mRNA levels during the estrous cycle. Linearity of standards for alpha, beta(A), and beta(B) subunit assays were between 0.01-0.3 amol, 0.003-0.09 amol and 0.002-0.02 amol of each fragment DNA as a standard, respectively. Hypothalamic beta(A) subunit mRNA during the estrous morning (1000 h) tended to be increased compared with that of the proestrous evening (1700 h), although they were not significantly different. Ovarian alpha subunit mRNA levels tended to be increased during the proestrous morning (1000 h) and were significantly increased in the proestrous evening (1700 h), compared with diestrus and estrus (P < 0.05). Ovarian beta(A) subunit mRNA was also significantly higher in the proestrous evening, compared with diestrus and estrus (P < 0.05), but in the case of beta(B) subunit mRNA there was no difference among diestrus, proestrus and estrus. We thus established a sensitive competitive RT-PCR system for the measurement of inhibin/activin alpha, beta(A) and beta(B) subunits, and this assay system would be helpful for the study of inhibin/activin action in brain and other tissues where these factors are expressed at low levels.

Immunolocalization of type I or type II activin receptors in the rat brain

We have studied immunolocalization of activin receptors in the central nervous system using polyclonal antibodies (IgG) to type I (50-55 kDa, ActRI), type II (70-75 kDa, ActRII) or a subtype of type II known as type IIB (ActRIIB) receptors of activin. A total of 7 antisera to rat activin receptors was generated, i.e. 3 kinds of antisera to the extracellular domain (ActRI(81-89), ActRII(91-100), or ActRIIB(90-99)) and 4 antisera to the kinase domain (ActRI(323-333), ActRII(307-319), ActRII(407-420) or ActRIIB(306-319)). The region of aa 407-420 of ActRII is identical with that of ActRIIB. At first, we characterized these antibodies by Western blot analysis using ovarian proteins fractionated by preparative SDS-PAGE. All antibodies to ActRII and ActRIIB specifically reacted with 75 kDa-proteins which could also bind to activin-A. Anti-ActRII(91-100) antibody also reacted with 62 kDa-proteins which were capable of binding with activin-A. Although no positive reactions to anti-ActRI(81-89) antibody were seen in ovarian proteins, a positive reaction was detected at 52 kDa only when the proteins were deglycosylated. By use of these antibodies, immunolocalization of activin receptors was examined in the rat brain. The patterns of expression of activin type I and type II receptors were different. Positive reactions to anti-ActRII(91-100) antibody were detected in neurons of the cerebral cortex, hippocampus, medial amygdala and thalamus. In the hypothalamus, some neurons of the supraoptic nucleus were weakly stained, and widely scattered neurons of the lateral hypothalamic area were moderately stained. On the contrary, the most intense reactions to anti-ActRI(81-89) antibody were detected in neurons of the lateral hypothalamic area. In addition, many neurons of the cerebral cortex were also stained, but neurons of the hippocampus and the amygdala were not stained. These results suggest that activin may have physiological roles not only for hypothalamic neuroendocrinological and feeding-related systems as suggested previously but may also have functions in cortical and limbic pathways as a neuromodulator or for maintenance of neurons.

Chronic inflammatory demyelinating polyneuropathy accompanied by hepatocellular carcinoma

We report a patient with chronic inflammatory demyelinating polyneuropathy (CIDP) accompanied by hepatocellular carcinoma (HCC). Due to the remarkable weakness in the lower limbs and loss of the position sense, he could not walk. On neurophysiological examination, he had impaired nerve conduction velocities. Biopsied nerve and muscle specimens demonstrated demyelination of nerve fibers and neurogenic degeneration of muscles. After steroid therapy he showed marked improvement in muscle strength and sensory function.

Accumulation of peripheral myelin protein 22 in onion bulbs and Schwann cells of biopsied nerves from patients with Charcot-Marie-Tooth disease type 1A

Peripheral myelin protein 22 (PMP-22) is a glycoprotein expressed in the myelin sheath of myelinated Schwann cells. Duplication of the PMP-22 gene and its gene dosage effect have been postulated to be involved in the pathogenesis in the majority of individuals with Charcot-Marie-Tooth disease type 1A (CMT1A). Northern blot analysis has demonstrated that the mean relative ratio of PMP-22 mRNA/beta-actin mRNA in biopsied nerves of patients with CMT1A is significantly higher than that in disease controls. To investigate whether the elevated expression of PMP-22 mRNA is reflected in the amount and the localization of PMP-22, we analyzed PMP-22, myelin basic protein (MBP), protein zero (P0), and S-100 immunoreactivities in biopsied nerves from six patients with CMT1A, five patients with other types of CMT, five patients with acquired demyelinating neuropathies, and two normal subjects. In all patients with CMT other than CMT1A and acquired demyelinating neuropathy, as well as in normal subjects, the myelin sheath was immunoreactive for PMP-22, MBP, and P0, while the Schwann cell cytoplasm was immunoreactive only for S-100. In five out of six patients with CMT1A, however, the PMP-22 immunoreactivity was present not only on the myelin sheath but also in the Schwann cell cytoplasm and onion bulbs (OBs). Although OBs are nonspecific and also seen in other inherited or acquired demyelinating neuropathies, the PMP-22-positive OBs were seen exclusively in CMT1A. The finding suggested that the expression of PMP-22 was abnormal for its localization and probably for the amount in patients with CMT1A carrying duplication of the PMP-22 gene.

Pentoxifylline delays the onset of experimental allergic encephalomyelitis in mice by modulating cytokine production in peripheral blood mononuclear cells

The effect of pentoxifylline (PTX) on experimental allergic encephalomyelitis (EAE) in mice, a known animal model of multiple sclerosis (MS), was investigated. PTX was orally administrated at 10, 40 and 100 mg/kg/day, respectively. Although oral PTX at these doses had no significant effect on the incidence and severity of EAE, oral PTX (40 mg/kg/day) alone produced a significant delay in the onset of EAE. Semiquantitative reverse transcriptase-polymerase chain reaction analysis revealed that PTX at this dose reduced the mRNA levels for tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta and IL-6 in peripheral blood mononuclear cells (PBMC) of mice with EAE. A histopathological study showed that PTX treatment delayed infiltration of inflammatory cells in the central nervous system (CNS) of mice with EAE. These results indicated that the tolerable dose of PTX had a suppressive effect on the induction phase of EAE by modulating cytokine production in PBMC but had no effect on the severity of EAE. The findings in the present study with animals suggested that a tolerable dose of PTX might prolong the intervals between relapses in MS, but might not improve the clinical sign and symptoms of MS.

The immunosuppressant leflunomide blocks the yeast Saccharomyces cerevisiae cell cycle at the G1 phase

Leflunomide is a novel immunomodulatory drug representing a new small molecule class of substances which are structurally unrelated to previously described immunomodulatory/immunosuppressive compounds. The effect of leflunomide on the cell cycle of Saccharomyces cerevisiae was investigated to elucidate the molecular mechanism of its action in eukaryotic organisms. When yeast cells were treated with leflunomide, unbudded cells were accumulated, suggesting that leflunomide may arrest the cell cycle in the G1 phase. When leflunomide-treated cells were subjected to heat shock treatment, the cells became resistant to heat shock treatment, implying that leflunomide-mediated block to cell division results in entry from the proliferative cycle into the alternative developmental G0 phase.