Safety and efficacy of a splenectomy during debulking surgery for Müllerian carcinoma

PURPOSE

This study was designed to assess the safety and efficacy of a splenectomy and to analyze the prognostic factors of Müllerian carcinoma with spleen metastasis.

METHODS

We reviewed the medical records of 11 patients with Müllerian carcinoma who underwent a splenectomy between 1997 and 2007. The treatment outcome of these patients was examined and the possible prognostic factors were investigated by univariate analysis.

RESULTS

Four and seven patients underwent a splenectomy for primary and recurrent disease, respectively. A complete resection was achieved in eight patients. A blood transfusion was not required and only two mild postoperative complications were observed. The median and five-year survivals of all patients following treatment were 39 months and 39%, respectively. Older patients (> or = 60 years old) and patients with a poor performance status (PS2) had a poorer prognosis by univariate analysis.

CONCLUSIONS

A splenectomy can be performed safely and effectively during debulking surgery for appropriately selected patients with primary or recurrent Müllerian carcinoma.

Lymphoepithelial-like carcinoma of the uterine cervix; a case report

Lymphoepithelioma-like carcinoma (LELC) of the uterine cervix is a rare variant of squamous cell carcinoma of the uterine cervix. This tumor is characterized by nests of poorly differentiated epithelial cells surrounded by a prominent lymphocytic infiltration. Despite the poorly differentiated pathological findings, it appears to have a better outcome than the usual squamous cell carcinoma of the uterine cervix. Therefore, it is quite important to differentiate this tumor from poorly differentiated squamous cell carcinoma and lympho-proliferative disorders of the cervix. LELC arising from the nasopharynx has been suggested to be associated with Epstein-Barr virus (EBV), whereas the involvement of EBV in LELC of the uterine cervix is still controversial. In addition, the role of high-risk human papilloma virus (HPV) in this type of tumor remains unknown. We report a case of LELC of the cervix with diagnosis on the basis of histopathology in a 52-year-old Japanese woman who presented with a history of continuous bleeding post menopause. We also examine the association of EBV and HPV in this case.

THE FAS/FAS-LIGAND PATHWAY DOES NOT MEDIATE THE APOPTOSIS IN ELASTASE-INDUCED EMPHYSEMA IN MICE

Porcine pancreatic elastase (PPE), which induces emphysema via apoptosis, was administered to wild-type and Fas-deficient (lpr) mice. On days 3 and 28 after administration, the mean linear intercepts within lung tissues were significantly higher in PPE-treated wild-type and lpr mice than in control mice, though there were no significant differences between the PPE-treated groups. Likewise, the numbers of TUNEL-positive cells were increased in the lungs of PPE-treated wild-type and lpr mice, and again the effect was similar in the two PPE-treated groups. These findings suggest that apoptosis associated with PPE-induced emphysema is not mediated via the Fas/Fas-ligand pathway.

BENEFICIAL EFFECTS OF AUTOLOGOUS BONE MARROW MONONUCLEAR CELL TRANSPLANTATION AGAINST ELASTASE-INDUCED EMPHYSEMA IN RABBITS

The authors investigated whether autologous bone marrow mononuclear cell (BMC) transplantation via the left and right main bronchi would mitigate elastase-induced pulmonary emphysema in rabbits. Four weeks after elastase administration, rabbits also receiving BMCs showed significantly better pulmonary function (FVC, FEV100, FEVPEF) and smaller alveolar airspaces, as indicated by a smaller mean linear intercept, than those receiving porcine pancreatic elastase (PPE) (200 U/kg) alone via the left and right main bronchi. BMCs also significantly reduced cell counts in bronchoalveolar lavage fluid, the incidence of apoptotic (TUNEL-positive) cells and matrix metalloproteinase (MMP)-2 expression, while increasing numbers of proliferative (Ki-67-positive) cells. Thus, BMCs may inhibit the progression to emphysema by attenuating inflammation, MMP-2 expression, and apoptosis, while enhancing alveolar cell proliferation.

Increase in hemokinin-1 mRNA in the spinal cord during the early phase of a neuropathic pain state

BACKGROUND AND PURPOSE

Substance P (SP), a representative member of the tachykinin family, is involved in nociception under physiological and pathological conditions. Recently, hemokinin-1 (HK-1) was identified as a new member of this family. Although HK-1 acts on NK(1) tachykinin receptors that are thought to be innate for SP, the roles of HK-1 in neuropathic pain are still unknown.

EXPERIMENTAL APPROACH

Using rats that had been subjected to chronic constrictive injury (CCI) of the sciatic nerve as a neuropathic pain model, we examined the changes in expression of SP- and HK-1-encoding genes (TAC1 and TAC4, respectively) in the L4/L5 spinal cord and L4/L5 dorsal root ganglia (DRGs) in association with changes in pain-related behaviours in this neuropathic pain state.

KEY RESULTS

The TAC4 mRNA level was increased on the ipsilateral side of the dorsal spinal cord, but not in DRGs, at day 3 after CCI. In contrast, the TAC1 mRNA level was significantly increased in the DRGs at day 3 after CCI without any changes in the dorsal spinal cord. Analysis of a cultured microglial cell line revealed the presence of TAC4 mRNA in microglial cells. Minocycline, an inhibitor of microglial activation, blocked the increased expression of TAC4 mRNA after CCI and inhibited the associated pain-related behaviours and microglial activation in the spinal cord.

CONCLUSIONS AND IMPLICATIONS

The present results suggest that HK-1 expression is increased at least partly in activated microglial cells after nerve injury and is clearly involved in the early phase of neuropathic pain.

[Paraneoplastic neurological syndrome accompanied by severe central hypoventilation and expression of anti-Hu antibody in a patient with small cell lung cancer]

A 65-year-old man was admitted to our hospital complaining of diplopia, dysarthria, difficulty in walking and progressive dysesthesia that developed in his left hand and leg. Brain MRI revealed high signal intensity regions on T2-weighted and FLAIR images of the hippocampus and the corpus amygdaloideum. After admission, the patient's neurological symptoms progressed to delirium and dementia with hallucinations. When he eventually developed severe respiratory failure requiring ventilatory support, brain MRI revealed new high signal intensity regions on T2-weighted images of the medulla oblongata and pons. Chest CT scans showed a mass under the aortic arch, and based on subsequent histopathological examination of a transesophageal endoscopic ultrasonography-guided fine needle aspiration biopsy of the tumor, a diagnosis of small cell lung cancer was made. In addition, anti-Hu antibody was found in the patient's serum, leading to a diagnosis of paraneoplastic encephalomyelitis/sensory neuropathy. One course of chemotherapy (carboplatin + etoposide) was administered; however, the protocol was not completed because the patient developed severe pneumonia. Given that neurological symptoms usually precede a diagnosis of malignancy in paraneoplastic neurological syndromes, it is important that these are considered carefully, as they may contribute to early diagnosis and treatment. Here we report a rare case of severe central hypoventilation in paraneoplastic encephalomyelitis/sensory neuropathy.

Surgical treatment for neuroendocrine carcinoma of the uterine cervix

OBJECTIVE

To identify the best operative approach for neuroendocrine cervical carcinoma (NECC).

METHODS

The records of surgically treated patients with stages IB to IIB NECC were reviewed.

RESULTS

Of 10 patients who met the study criteria for NECC and underwent radical hysterectomy, 4 had pT1bN0, 4 had pT1bN1, 1 had pT2aN0, and 1 had pT2bN1 disease. Those with pT1bN1 or pT2bN1 disease received postoperative adjuvant radiotherapy and/or chemotherapy, and recurrence occurred in 7 patients (70%). Among these 7 patients, 5 (71%) had a primary NECC tumor with deep stromal invasion and 5 (71%) had extrauterine disease (parametrium and/or lymph node). The recurrences in 6 patients (86%) were located outside the pelvis (lung, liver, or brain). Stromal invasion was 6 mm or less in the 3 patients who did not experience disease recurrence.

CONCLUSIONS

Pelvic control by radical hysterectomy may not be beneficial for patients with NECC except for those with an early invasive lesion.

Narirutin inhibits airway inflammation in an allergic mouse model

1. Flavonoids are naturally occurring compounds that possess anti-allergic, anti-inflammatory, antiproliferative and anti-oxidant properties. In the present study, we investigated whether the flavonoid narirutin could reduce airway inflammation in ovalbumin (OVA)-sensitized/challenged NC/Nga mice, a model of allergic eosinophilic airway inflammation. 2. Mice were initially immunized intraperitoneally with OVA on Days 0 and 7 and then challenged with inhaled OVA on Days 14, 15 and 16. In addition, some mice received narirutin orally at doses of 0.1, 1 or 10 mg/kg bodyweight daily on Days 7-16. 3. At 10 mg/kg, but not 0.1 or 1 mg/kg, narirutin significantly diminished OVA-induced airway inflammation caused by infiltration of lung tissue with inflammatory and mucus-producing cells, as well as reduced eosinophil counts in the peripheral blood and bronchoalveolar lavage fluid (BALF), interleukin (IL)-4 levels in BALF and IgE levels in serum. 4. The mechanism of the anti-inflammatory effect of narirutin are likely to be associated with a reduction in the OVA-induced increases of IL-4 and IgE in a murine model of allergic eosinophilic airway inflammation. These findings suggest that narirutin may be an effective new tool in the treatment of bronchial asthma.

THE SPECIFIC FREE RADICAL SCAVENGER EDARAVONE SUPPRESSES BLEOMYCIN-INDUCED ACUTE PULMONARY INJURY IN RABBITS

1. Intratracheal instillation of bleomycin induces a condition in rabbits that serves as a useful model of human pulmonary fibrosis. Bleomycin-induced production of reactive oxygen species leads to acute lung inflammation and induction of apoptosis, which is followed by pulmonary fibrosis at a later chronic stage. In the present study, we tested whether edaravone, a free radical scavenger, would suppress bleomycin-induced acute pulmonary inflammation. 2. Rabbits were divided into three groups (n = 10 in each): (i) a bleomycin-treated group, which received intratracheal instillation of 2 mg/kg bleomycin; (ii) a bleomycin + edaravone group, which received a 10 day regimen of daily intravenous injections of edaravone (3 mg/kg per day) beginning 3 days before bleomycin instillation; and (iii) a saline control group. Rabbits were killed for analysis 7 days after bleomycin administration. 3. In lung tissues from the bleomycin-treated group, marked infiltration of inflammatory cells, consisting mainly of lymphocytes, neutrophils and eosinophils, was observed. In addition, significantly increased numbers of TUNEL-positive (apoptotic) and transforming growth factor-beta-positive cells were seen. All these effects were significantly attenuated by treatment with edaravone. 4. The findings of the present study suggest that edaravone may be useful in the prevention of acute lung injury resulting from the production of reactive oxygen species.

Biochemistry of postmortem brains in Parkinson's disease: historical overview and future prospects

Biochemical studies on postmortem brains of patients with Parkinson's disease (PD) have greatly contributed to our understanding of the molecular pathogenesis of this disease. The discovery by 1960 of a dopamine deficiency in the nigro-striatal dopamine region of the PD brain was a landmark in research on PD. At that time we collaborated with Hirotaro Narabayashi and his colleagues in Japan and with Peter Riederer in Germany on the biochemistry of PD by using postmortem brain samples in their brain banks. We found that the activity, mRNA level, and protein content of tyrosine hydroxylase (TH), as well as the levels of the tetrahydrobiopterin (BH4) cofactor of TH and the activity of the BH4-synthesizing enzyme, GTP cyclohydrolase I (GCHI), were markedly decreased in the substantia nigra and striatum in the PD brain. In contrast, the molecular activity (enzyme activity/enzyme protein) of TH was increased, suggesting a compensatory increase in the enzyme activity. The mRNA levels of all four isoforms of human TH (hTH1-hTH4), produced by alternative mRNA splicing, were also markedly decreased. This finding is in contrast to a completely parallel decrease in the activity and protein content of dopamine beta-hydroxylase (DBH) without changes in its molecular activity in cerebrospinal fluid (CSF) in PD. We also found that the activities and/or the levels of the mRNA and protein of aromatic L-amino acid decarboxylase (AADC, DOPA decarboxylase), DBH, phenylethanolamine N-methyltransferase (PNMT), which synthesize dopamine, noradrenaline, and adrenaline, respectively, were also decreased in PD brains, indicating that all catecholamine systems were widely impaired in PD brains. Programmed cell death of the nigro-striatal dopamine neurons in PD has been suggested from the following findings on postmortem brains: (1) increased levels of pro-inflammatory cytokines such as TNF-alpha and IL-6; (2) increased levels of apoptosis-related factors such as TNF-alpha receptor R1 (p 55), soluble Fas and bcl-2, and increased activities of caspases 1 and 3; and (3) decreased levels of neurotrophins such as brain-derived nerve growth factor (BDNF). Immunohistochemical data and the mRNA levels of the above molecules in PD brains supported these biochemical data. We confirmed by double immunofluorescence staining the production of TNF-alpha and IL-6 in activated microglia in the putamen of PD patients. Owing to the recent development of highly sensitive and wide-range analytical methods for quantifying mRNAs and proteins, future assays of the levels of various mRNAs and proteins not only in micro-dissected brain tissues containing neurons and glial cells, but also in single cells from frozen brain slices isolated by laser capture micro-dissection, coupled with toluidine blue, Nissl staining or immunohistochemical staining, should further contribute to the elucidation of the molecular pathogenesis of PD and other neurodegenerative or neuropsychiatric diseases.

Recombinant human lactoferrin has a potential to suppresses uterine cervical ripening in preterm delivery in animal model

OBJECTIVE

To investigate the effect of recombinant human lactoferrin (rhLF) on cervical ripening using a rabbit model in which preterm labor was induced by bacterial endotoxin lipopolysaccharide (LPS).

STUDY DESIGN

Timed pregnant rabbits (New Zealand White, 3-4 kg, day 14) were randomly assigned to the following treatment groups: Group A, LPS + rhLF (n = 4); Group B, LPS (n = 4); and Group C, control (n = 4). Recombinant human lactoferrin (10 microg) was administrated to pregnant rabbits in Group A and not in Group B. Lipopolysaccharide (100 microg) was given to the rabbits in both groups for 3 days (days14-16). Drugs were administered as a vaginal suppository. On day 18, the rabbits were anesthetized with intramuscular ketamine hydrochloride (20 mg/kg) and diazepam (4 mg/kg). Both cervices of the rabbit uterus, which is bicorpus-bicolli, were taken out. One cervix was placed in 10% formalin solution for a histological study with standard hematoxylin-eosin staining. The other was used for an extension test to assess the grade of ripening. Extension was measured after a 5-mm length of cervical tissue was loaded with 5.8 g.

RESULTS

The histological study showed remarkably loose and edematous connective tissue in Group B cervices. Cervical tissues in Group A was not different from those in Group C. Extension lengths were 2.2 +/- 0.2 mm in Group A, 7.0 +/- 2.7 mm in Group B, and 1.7 +/- 0.3 mm in Group C.

CONCLUSION

These results suggest that rhLF inhibits cervical maturation induced by LPS in a rabbit model and may have a potential to prevent preterm delivery caused by cervical infection and ripening.

The intra-arterial injection of microglia protects hippocampal CA1 neurons against global ischemia-induced functional deficits in rats

In the present study, we have attempted to elucidate the effects of the intra-arterial injection of microglia on the global ischemia-induced functional and morphological deficits of hippocampal CA1 neurons. When PKH26-labeled immortalized microglial cells, GMIR1, were injected into the subclavian artery, these exogenous microglia were found to accumulate in the hippocampus at 24 h after ischemia. In hippocampal slices prepared from medium-injected rats subjected to ischemia 48 h earlier, synaptic dysfunctions including a significant reduction of synaptic responses and a marked reduction of long-term potentiation (LTP) of the CA3-CA1 Schaffer collateral synapses were observed. At this stage, however, neither significant neuronal degeneration nor gliosis was observed in the hippocampus. At 96 h after ischemia, there was a total loss of the synaptic activity and a marked neuronal death in the CA1 subfield. In contrast, the basal synaptic transmission and LTP of the CA3-CA1 synapses were well preserved after ischemia in the slices prepared from the microglia-injected animals. We also found the microglial-conditioned medium (MCM) to significantly increase the frequency of the spontaneous postsynaptic currents of CA1 neurons without affecting the amplitude, thus indicating that MCM increased the provability of the neurotransmitter release. The protective effect of the intra-arterial injected microglia against the ischemia-induced neuronal degeneration in the hippocampus was substantiated by immunohistochemical and immunoblot analyses. Furthermore, the arterial-injected microglia prevented the ischemia-induced decline of the brain-derived neurotrophic factor (BDNF) levels in CA1 neurons. These observations strongly suggest that the arterial-injection of microglia protected CA1 neurons against the ischemia-induced neuronal degeneration. The restoration of the ischemia-induced synaptic deficits and the resultant reduction of the BDNF levels in CA1 neurons, possibly by the release of diffusible factor(s), might thus contribute to the protective effect of the arterial-injection of microglia against ischemia-induced neuronal degeneration.

Dependence of fragmentation behavior of colloidal aggregates on their fractal structure

The fragmentation dynamics of aggregate of non-Brownian particles in shear flow is investigated numerically. The breakup behaviors of aggregates having the same connectivity but the different space-filling properties are examined. The Lagrangian particle simulation in a linear flow field is performed. The effect of surrounding fluid on the motion of multiple particles is estimated by Stokesian dynamics approach. The inter-particle force is calculated from the retarded van der Waals potential based on the Lifshitz theory. The results obtained in this work indicate that the fragmentation behavior of colloidal aggregates depends on their fractal structure. However, if the resultant aggregate size is smaller than the critical one, the fragmentation behavior shows the universality regardless of their original structure. Furthermore, the restructuring of aggregate in shear flow and its effect on the fragmentation process are also discussed.

Endoscopic ultrasound-guided fine-needle aspiration biopsy for lymphadenopathy of unknown origin

BACKGROUND AND STUDY AIMS

The diagnosis of mediastinal and intra-abdominal lymphadenopathy is sometimes difficult, especially in patients who have no other primary lesions. Lymphoma is one of the main causes of this condition. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a safe and accurate diagnostic procedure for lesions surrounding the gastrointestinal tract. However, diagnosing lymphoma using the EUS-FNA technique remains a diagnostic challenge, due to limitations in the amount of material sampled. The aim of the present study was to evaluate the yield of EUS-FNA biopsy (EUS-FNAB) using a large-gauge needle in patients with mediastinal and intra-abdominal lymphadenopathy of unknown origin, especially in relation to subclassification of the lymphomas.

PATIENTS AND METHODS

Consecutive patients with mediastinal and intra-abdominal lymphadenopathy of unknown origin who were referred between October 2003 and March 2005 were enrolled in the study. EUS-FNAB was carried out using a 19-gauge needle, passing through the esophageal, gastric, and duodenal walls. Pathological diagnoses were made on the basis of histological findings, including immunopathological staining.

RESULTS

A total of 104 patients were included in the study. The locations of the lymph nodes were mediastinal in 50 patients, intra-abdominal in 48 patients, and both mediastinal and intra-abdominal in six patients. The diagnoses made using EUS-FNAB were lymphoma (n = 48), metastasis (n = 16), and benign/reactive (n = 40). The overall accuracy of EUS-FNAB for unknown lymphadenopathy was 98 %, and it was possible to classify the lymphomas in accordance with the World Health Organization classifications in 88 % of cases. No serious complications occurred with the procedure.

CONCLUSIONS

Open thoracic surgery, laparotomy, and other invasive diagnostic procedures such as mediastinoscopy and laparoscopy can now be avoided, as EUS-FNAB is potentially a safe and accurate tool for diagnosing unknown lymphadenopathy, including lymphoma.

Expression of lactate dehydrogenase-A and -B messenger ribonucleic acids in chick glycogen body

Glucose is a main metabolic substrate in the central nervous system (CNS). Recently, lactate has attracted renewed attention because it plays an important role in the CNS as a metabolic substrate between neurons and astrocytes. Lactate and lactate dehydrogenase (LDH), a key enzyme for lactate and pyruvate interconversion, have been investigated. The glycogen body (GB) is a gelatinous tissue in the dorsal area of the lumbosacral spinal cord in birds. It is composed of uniform cells with high glycogen storage and is thought to be in the astroglia lineage. In this article, we investigated the LDH enzyme activity in embryo GB (embryonic d 12, 14, 16, 17, and 18) and chickens. To detect the subtype of the LDH, mRNA expressions in GB were investigated and compared with those of cerebral cortex and spinal cord. By histochemical observations, LDH enzyme activity was detected in the cytoplasm of GB cells of all embryonic periods after embryonic d 12. In biochemical analysis, the enzymatic activities of the GB were higher than in the cerebral cortex. In the GB the subtype of LDH mRNA was LDM-B only, and in the cerebral cortex and spinal cord, the subtype of LDH mRNA was predominantly LDH-B, and a small amount of LDH-A was found in the chicken and embryo. The LDH-B mRNA expression in GB was detected during all periods of the study (after embryonic d 12). These observations suggest that GB expressed only LDH-B and that GB cells are not lactate-producing cells, like astrocyte, but rather are lactate-consuming cells, similar to neurons in CNS.

Effect of MKC-733, a 5-HT receptor partial agonist, on bowel motility and symptoms in subjects with constipation: an exploratory study

BACKGROUND

MKC-733, a 5-HT(3) receptor partial agonist, is a novel enteroprokinetic compound.

OBJECTIVE

The aim of this study was to explore the effects of MKC-733 on bowel motility and symptoms in a small group of subjects with constipation. Tolerability was also examined.

METHODS

The study was conducted in a single-blind and dose-escalation manner on 14 male and female subjects with constipation aged 22-67 years. After a 1 week run-in period, subjects were treated with placebo (b.i.d.) for 1 week, and 0.2 and 0.5 mg of MKC-733 (b.i.d.) for 2 weeks sequentially. Geometric mean and per cent elimination of surrogate markers of bowel motility were measured by a radio-opaque marker technique at the end of each treatment period. They were analysed on the whole group and subgroups with low (n = 6) and high (n = 8) bowel motility based upon the geometric mean value after placebo treatment. Subjects kept diaries of their bowel habits and gastrointestinal symptoms.

RESULTS

Percent elimination increased after treatment with 0.5 mg MKC-733 compared with placebo treatment in the whole group (70.4 +/- 33.5% vs. 47.1 +/- 36.6%, mean +/- SD, P < 0.05). In the low bowel motility group, both geometric mean and percent elimination increased after treatment with 0.5 mg MKC-733 compared with placebo (7.1 +/- 0.9 vs. 5.9 +/- 0.5, P < 0.05; 60.0 +/- 35.8% vs. 13.3 +/- 19.4%, P < 0.05). Stool frequency increased after the first-week treatment with MKC-733 compared with placebo (P < 0.05). Numbers of sensation of incomplete evacuation and gastrointestinal symptoms decreased to half and less after the treatment with MKC-733. No serious adverse effect was noted.

CONCLUSION

Multiple doses of 0.5 mg MKC-733 improve bowel motility, which was clearly demonstrated in the subjects with decreased bowel motility. MKC-733 at the doses studied might be effective in increasing stool frequency and reduce gastrointestinal symptoms related to constipation. MKC-733 was well tolerated. Further studies will be needed to clarify efficacy and safety of MKC-733 on a larger population.

Carotid Artery Angioplasty and Stenting as a First-choice Revascularization Therapy for Cervical Carotid Artery Stenosis

SUMMARY

We examined the patients with cervical carotid artery stenosis (> 70%) treated by carotid artery angioplasty and stenting (CAS) as a firstchoice direct revascularization therapy. The patients consisted of 45 men and seven women; their mean age was 70.4 years (range, 54-84 yr), with 60 cervical carotid stenosis (39 symptomatic and 21 asymptomatic). Sixty procedures resulted in successful stent deployment in 55 cases, percutaneous transluminal angioplasty (PTA) only without stenting in three, and failed angioplasty due to inaccessibility in two. Morbidity was seen in three cases associated with thromboembolic complication. Instent restenosis was observed in one case, which was successfully treated with subsequent PTA. CAS seems reasonable treatment for cervical carotid artery stenosis, although further accumulation of the cases will be needed to evaluate the efficacy between CAS and carotid endarterectomy.

Molecular mechanism of the relation of monoamine oxidase B and its inhibitors to Parkinson's disease: possible implications of glial cells

Monoamine oxidases A and B (MAO A and MAO B) are the major enzymes that catalyze the oxidative deamination of monoamine neurotaransmitters such as dopamine (DA), noradrenaline, and serotonin in the central and peripheral nervous systems. MAO B is mainly localized in glial cells. MAO B also oxidizes the xenobiotic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to a parkinsonism-producing neurotoxin, 1-methyl-4-phenyl-pyridinium (MPP+). MAO B may be closely related to the pathogenesis of Parkinson's disease (PD), in which neuromelanin-containing DA neurons in the substantia nigra projecting to the striatum in the brain selectively degenerate. MAO B degrades the neurotransmitter DA that is deficient in the nigro-striatal region in PD, and forms H2O2 and toxic aldehyde metabolites of DA. H2O2 produces highly toxic reactive oxygen species (ROS) by Fenton reaction that is catalyzed by iron and neuromelanin. MAO B inhibitors such as L-(-)-deprenyl (selegiline) and rasagiline are effective for the treatment of PD. Concerning the mechanism of the clinical efficacy of MAO B inhibitors in PD, the inhibition of DA degradation (a symptomatic effect) and also the prevention of the formation of neurotoxic DA metabolites, i.e., ROS and dopamine derived aldehydes have been speculated. As another mechanism of clinical efficacy, MAO B inhibitors such as selegiline are speculated to have neuroprotective effects to prevent progress of PD. The possible mechanism of neuroprotection of MAO B inhibitors may be related not only to MAO B inhibition but also to induction and activation of multiple factors for anti-oxidative stress and anti-apoptosis: i.e., catalase, superoxide dismutase 1 and 2, thioredoxin, Bcl-2, the cellular poly(ADP-ribosyl)ation, and binding to glyceraldehydes-3-phosphate dehydrogenase (GAPDH). Furthermore, it should be noted that selegiline increases production of neurotrophins such as nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and glial cell line-derived neurotrphic factor (GDNF), possibly from glial cells, to protect neurons from inflammatory process.

Role of cytokines in inflammatory process in Parkinson's disease

We investigated whether the cytokines produced in activated microglia in the substantia nigra (SN) and putamen in sporadic Parkinson's disease (PD) are neuroprotective or neurotoxic. In autopsy brains of PD, the number of MHC class II (CR3/43)-positive activated microglia, which were also ICAM-1 (CD 54)-, LFA-1 (CD 11a)-, TNF-alpha-, and IL-6-positive, increased in the SN and putamen during progress of PD. At the early stage activated microglia were mainly associated with tyrosine hydroxylase (TH)-positive neurites in the putamen, and at the advanced stage with damaged TH-positive neurons in the SN. The activated microglia in PD were observed not only in the nigro-striatal region, but also in various brain regions such as the hippocampus and cerebral cortex. We examined the distribution of activated microglia and the expression of cytokines and neurotrophins in the hippocampus of PD and Lewy body disease (LBD). The levels of IL-6 and TNF-alpha mRNAs increased both in PD and LBD, but those of BDNF mRNA and protein drastically decreased specifically in LBD, in which neuronal loss was observed not only in the nigro-striatum but also in the hippocampus. The results suggest activated microglia in the hippocampus to be probably neuroprotective in PD, but those to be neurotoxic in LBD. As an evidence supporting this hypothesis, two subsets of microglia were isolated from mouse brain by cell sorting: one subset with high production of reactive oxygen species (ROS) and the other with no production of ROS. When co-cultured with neuronal cells, one microglia clone with high ROS production was neurotoxic, but another clone with no ROS production neuroprotective. On the other hand, Sawada with coworkers found that a neuroprotective microglial clone in a culture experiment converted to a toxic microglial clone by transduction of the HIV-1 Nef protein with increasing NADPH oxidase activity. Taken together, all these results suggest that activated microglia may change in vivo from neuroprotective to neurotoxic subtsets as degeneration of dopamine neurons in the SN progresses in PD. We conclude that the cytokines from activated microglia in the SN and putamen may be initially neuroprotective, but may later become neurotoxic during the progress of PD. Toxic change of activated microglia may also occur in Alzheimer's disease and other neurodegenerative diseases in which inflammatory process is found.