Characterization of Pleural Mesothelioma by Hierarchical Clustering Analyses Using Immune Cells within Tumor Microenvironment

INTRODUCTION

Over the past decade, classifications using immune cell infiltration have been applied to many types of tumors; however, mesotheliomas have been less frequently evaluated.

METHODS

In this study, 60 well-characterized pleural mesotheliomas (PMs) were evaluated immunohistochemically for the characteristics of immune cells within tumor microenvironment (TME) using 10 immunohistochemical markers: CD3, CD4, CD8, CD56, CD68, CD163, FOXP3, CD27, PD-1, and TIM-3. For further characterization of PMs, hierarchical clustering analyses using these 10 markers were performed.

RESULTS

Among the immune cell markers, CD3 (p < 0.0001), CD4 (p = 0.0016), CD8 (p = 0.00094), CD163+ (p = 0.042), and FOXP3+ (p = 0.025) were significantly associated with an unfavorable clinical outcome. Immune checkpoint receptor expressions on tumor-infiltrating lymphocytes such as PD-1 (p = 0.050), CD27 (p = 0.014), and TIM-3 (p = 0.0098) were also associated with unfavorable survival. Hierarchical clustering analyses identified three groups showing specific characteristics and significant associations with patient survival (p = 0.016): the highest number of immune cells (ICHigh); the lowest number of immune cells, especially CD8+ and CD163+ cells (ICLow); and intermediate number of immune cells (ICInt). ICHigh tumors showed significantly higher expression of PD-L1 (p = 0.00038). Cox proportional hazard model identified ICHigh [hazard ratio (HR) = 2.90] and ICInt (HR = 2.97) as potential risk factors compared with ICLow. Tumor CD47 (HR = 2.36), tumor CD70 (HR = 3.04), and tumor PD-L1 (HR = 3.21) expressions were also identified as potential risk factors for PM patients.

CONCLUSION

Our findings indicate immune checkpoint and/or immune cell-targeting therapies against CD70-CD27 and/or CD47-SIRPA axes may be applied for PM patients in combination with PD-L1-PD-1 targeting therapies in accordance with their tumor immune microenvironment characteristics.

Simultaneous Expression of CD70 and POSTN in Cancer-Associated Fibroblasts Predicts Worse Survival of Colorectal Cancer Patients

Colorectal cancer (CRC) is one of the most common gastrointestinal cancers worldwide, with high morbidity and mortality rates. The evidence for the tumor-supporting capacities of cancer-associated fibroblasts (CAFs) that modulate cancer cell proliferation, invasion, metastasis, and tumor immunity, including in CRC, has been attracting attention. The present study examined the expression status of CD70 and POSTN in CRC and analyzed their association with clinicopathological features and clinical outcomes. In the present study, in total 15% (40/269) and 44% (119/269) of cases exhibited CD70 and POSTN expression on CAFs, respectively. Co-expression of CD70 and POSTN was detected in 8% (21/269) of patients. Fluorescent immunohistochemistry identified the co-expression of CD70 and POSTN with FAP and PDPN, respectively. ACTA2 was not co-expressed with CD70 or POSTN in CRC CAFs. CRC with CD70+/POSTN+ status in CAFs was significantly associated with distant organ metastasis (p = 0.0020) or incomplete resection status (p = 0.0011). CD70+/POSTN+ status tended to associate with advanced pT stage (p = 0.032) or peritoneal metastasis (p = 0.0059). Multivariate Cox hazards regression analysis identified CD70+/POSTN+ status in CAFs [hazard ratio (HR) = 3.78] as a potential independent risk factor. In vitro experiments revealed the activated phenotypes of colonic fibroblasts induced by CD70 and POSTN, while migration and invasion assays identified enhanced migration and invasion of CRC cells co-cultured with CD70- and POSTN-expressing colonic fibroblasts. On the basis of our observations, CD70 and POSTN immunohistochemistry can be used in the prognostication of CRC patients. CRC CAFs may be a promising target in the treatment of CRC patients.

Characterization of colorectal cancer by hierarchical clustering analyses of five immune cell markers

The present study analyzed the expression of five independent immunohistochemical markers, CD4, CD8, CD66b, CD68, and CD163, on immune cells within the colorectal cancer (CRC) tumor microenvironment (TME). Using hierarchical clustering, patients were successfully classified according to significant associations with clinicopathological features and/or survival. Patients with mismatch repair-proficient (pMMR) CRC were categorized into four groups with survival differences (p = 0.0084): CD4Low , CD4High , MΦHigh , and CD8Low . MΦHigh tumors showed significantly higher expression of CD47 (p < 0.0001), a phagocytosis checkpoint molecule. These tumors contained significantly greater numbers of PD-1+ (p < 0.0001), TIM-3+ (p < 0.0001), and SIRPA+ (p < 0.0001) immune cells. Notably, 10% of the patients with pMMR CRC expressed PD-L1 (CD274) on tumor cells with significantly worse survival (p = 0.00064). The Cox proportional hazards model identified MΦ High (hazard ratio [HR] = 2.02, 95%, p = 0.032), CD8Low (HR = 2.45, p = 0.011), and tumor PD-L1 expression (HR = 2.74, p = 0.0061) as potential risk factors. PD-L1-PD-1 and/or CD47-SIRPA axes targeting immune checkpoint therapies might be considered for patients with pMMR CRC according to their tumor cells and tumor immune microenvironment characteristics.

CD70 and PD-L1 (CD274) co-expression predicts poor clinical outcomes in patients with pleural mesothelioma

Diffuse pleural mesothelioma (PM) is a highly aggressive tumour typically associated with short survival. Recently, the effectiveness of first-line immune checkpoint inhibitors in patients with unresectable PM was reported. CD70-CD27 signalling plays a co-stimulatory role in promoting T cell expansion and differentiation through the nuclear factor κB (NF-κB) pathway. Conversely, the PD-L1 (CD274)-PD-1 (PDCD1) pathway is crucial for the modulation of immune responses in normal conditions. Nevertheless, pathological activation of both the CD70-CD27 and PD-L1-PD-1 pathways by aberrantly expressed CD70 and PD-L1 participates in the immune evasion of tumour cells. In this study, 171 well-characterised PMs including epithelioid (n = 144), biphasic (n = 15), and sarcomatoid (n = 12) histotypes were evaluated immunohistochemically for CD70, PD-L1, and immune cell markers such as CD3, CD4, CD8, CD56, PD-1, FOXP3, CD68, and CD163. Eight percent (14/171) of mesotheliomas simultaneously expressed CD70 and PD-L1 on the tumour cell membrane. PMs co-expressing CD70 and PD-L1 contained significantly higher numbers of CD8+ (p = 0.0016), FOXP3+ (p = 0.00075), and CD163+ (p = 0.0011) immune cells within their microenvironments. Overall survival was significantly decreased in the cohort of patients with PM co-expressing CD70 and PD-L1 (p < 0.0001). In vitro experiments revealed that PD-L1 and CD70 additively enhanced the motility and invasiveness of PM cells. In contrast, PM cell proliferation was suppressed by PD-L1. PD-L1 enhanced mesenchymal phenotypes such as N-cadherin up-regulation. Collectively, these findings suggest that CD70 and PD-L1 both enhance the malignant phenotypes of PM and diminish anti-tumour immune responses. Based on our observations, combination therapy targeting these signalling pathways might be useful in patients with PM.

Stromal POSTN Enhances Motility of Both Cancer and Stromal Cells and Predicts Poor Survival in Colorectal Cancer

Evidence for the tumor-supporting capacities of cancer-associated fibroblasts (CAFs) has rapidly been accumulating. To uncover clinicopathological importance of periostin (POSTN) expression in colorectal cancer (CRC), the present study immunohistochemically examined its expression status. Furthermore, to reveal its mechanisms involved, molecular experiments were performed. In CRC tissues, 44% of the cases (119/269) exhibited POSTN expression in the CAFs. In contrast, CRC cells expressed POSTN at almost undetectable levels. Survival analyses identified that patients with POSTN-positive CRC had a significantly worse 5-year survival rate (63.2% vs. 81.2%; p = 0.011). Univariate analyses revealed that POSTN positivity was associated with peritoneal (p = 0.0031) and distant organ metastasis (p < 0.001). Furthermore, immunohistochemical analyses identified a significant association between POSTN and p53 complete loss status in CRC cells. Decorin and fibroblast activation protein expression in CAFs was also associated with POSTN. POSTN significantly enhanced the migration of both CRC cells and fibroblasts with FAK and AKT or STAT3 activation, and co-culture assays demonstrated the communication between CRC cells and fibroblasts, which enhanced STAT3 activation in fibroblasts. On the basis of our results, we speculated that stromal POSTN accelerated metastasis via stromal remodeling capacity and activated the migration of both tumor and stromal cells.

The Complete Loss of p53 Expression Uniquely Predicts Worse Prognosis in Colorectal Cancer

p53 immunohistochemistry is considered an accurate surrogate marker reflecting the underlying TP53 mutation status and has utility in tumor diagnostics. In the present study, 269 primary CRCs were immunohistochemically evaluated for p53 expression to assess its utility in diagnostic pathology and prognostication. p53 expression was wild-type in 59 cases (23%), overexpressed in 143 cases (55%), completely lost in 50 cases (19%), and cytoplasmic in 10 cases (4%). p53 immunoreactivity was associated with tumor size (p = 0.0056), mucus production (p = 0.0015), and mismatch repair (MMR) system status (p < 0.0001). Furthermore, among CRCs with wild-type p53 expression, a significantly higher number of cases had decreased CDX2 than those with p53 overexpression (p = 0.012) or complete p53 loss (p = 0.043). In contrast, among CRCs with p53 overexpression, there were significantly fewer ALCAM-positive cases than p53 wild-type cases (p = 0.0045). However, no significant association was detected between p53 immunoreactivity and the “stem-like” immunophenotype defined by CDX2 downregulation and ALCAM-positivity. Multivariate Cox hazards regression analysis identified tubular-forming histology (hazard ratio [HR] = 0.17, p < 0.0001), younger age (HR = 0.52, p = 0.021), and female sex (HR = 0.55, p = 0.046) as potential favorable factors. The analysis also revealed complete p53 loss (HR = 2.16, p = 0.0087), incomplete resection (HR = 2.65, p = 0.0068), and peritoneal metastasis (HR = 5.32, p < 0.0001) as potential independent risk factors for patients with CRC. The sub-cohort survival analyses classified according to chemotherapy after surgery revealed that CRC patients with wild-type p53 expression tended to have better survival than those with overexpression or complete loss after chemotherapy. Thus, immunohistochemistry for p53 could be used for the prognostication and chemotherapy target selection of patients with CRC.

PBK Enhances Cellular Proliferation With Histone H3 Phosphorylation and Suppresses Migration and Invasion With CDH1 Stabilization in Colorectal Cancer

Colorectal cancer (CRC) is one of the most frequent gastrointestinal malignancies with high morbidity and mortality rates. Several biological markers for the prognostication of patient outcome of CRCs are available. Recently, our group identified two favorable factors for the survival of CRC patients: PDZ-binding kinase (PBK) and phospho-histone H3 (PHH3). Both showed a significant inverse association to pT stage. The aim of this study was to uncover the mechanism through which these cellular proliferation–associated protein expressions lead to favorable clinical outcome in CRC patients. We first confirmed co-expression of PBK and PHH3 in CRC cells. Further investigation showed that aberrantly expressed PBK up-regulated the cellular proliferation of CRC cells with accumulation of PHH3. The PBK inhibitor OTS514 suppressed cellular proliferation of CRC cells through down-regulation of PHH3 and induction of apoptosis. In vitro studies revealed that PBK suppressed the migration and invasion of CRC cells with suppression of Wnt/β-catenin signaling and CDH1 stabilization. Exogeneous PBK up-regulated the phosphorylated CDH1 at S840, S846, and S847 residues in cultured cells. Recombinant PBK directly phosphorylated HH3; however, it failed to phosphorylate CDH1 directly in vitro. The present study demonstrated the association of two markers PBK and PHH3 in CRC. We further identified one of the potential mechanisms by which higher expression of these cellular proliferation–associated proteins leads to the better survival of CRC patients, which likely involves PBK-mediated suppression of the migration and invasion of CRC cells. Our findings suggest that PBK-targeting therapeutics may be useful for the treatment of CRC patients with PBK-expressing tumors.

Secretory Ig a in Saliva and Academic Stress

Several reports have proposed that the concentration of secretory immunoglobulin A (S-IgA) in saliva is an indicator of psychological stress. With this in mind, we decided to examine it in 10 second year medical student volunteers at Kawasaki Medical School course between May 4 and July 13, 2000 and discussed the relationship between S-IgA and the stress from academic examinations. Saliva was collected three times (on rising, at forenoon, and at bedtime) every Thursday. During this period, sporadic academic examinations were held twice and term-end examinations occurred during the last two weeks. Results showed the concentration of S-IgA significantly higher at the on rising time-point than at the other two time-points. There was also a tendency for the S-IgA level in saliva to be higher on the day before academic examinations and during them and lower on the days between these examinations. In addition, daily variations in the S-IgA concentration sometimes seemed to be disturbed by other academic stress. Therefore, it may be possible to use this measurement to monitor psychological stress in students and workers.

An increased dose of insulin detemir improves glycaemic control and reduces body weight of Japanese patients with diabetes

AIMS

The aim of study was to evaluate the safety and efficacy of insulin detemir as a basal insulin switching from neutral protamine Hagedorn insulin (NPH) and insulin glargine in patients with diabetes on an intensive insulin therapy regimen.

METHODS

This 6-month multicentre, prospective, treat-to-target [glycosylated haemoglobin (HbA(1c) ) less than 6.5%] trial included 92 people with diabetes (61 type 1, 29 type 2 and two unknown diabetes types). Detemir was administered first with fixed dose and injection times and then adapted to optimal dose after 3 months.

RESULTS

Mean HbA(1c) (%) of all the subjects at months 4 to 6 of the study was improved compared with month 0 (7.34 ± 0.87, 7.28 ± 0.88, 7.25 ± 0.93 vs. 7.55 ± 1.18; p < 0.05 paired t-test). However, significant improvement was seen only among the patients who had previously used NPH as a basal insulin. Twice-daily injection of basal insulin increased among people in the type 1 previously injected insulin glargine. Total insulin dose increased in the type 1 glargine group. The mean body weight change in the highest quartile body mass index (BMI) group was from 70.7 to 69.3 kg over the 6 months. Quality of life (QoL) relating to the patients' glycaemic control tended to improve without a change in frequency of hypoglycaemia.

CONCLUSIONS

The results suggest that insulin detemir has a greater effect on glycaemic control in subjects with poor glycaemic control using NPH; can reduce or maintain body weight in obese patients; and obtains perceptive stability for patients with unstable glycaemic control.

Nerve growth factor attenuates hippocampal cholinergic deficits and operant learning impairment in rats with entorhinal cortex lesions

In the present study we investigated whether continuous intraventricular nerve growth factor (NGF) infusion could ameliorate hippocampal cholinergic deficits and learning impairment following entorhinal cortex lesions. Rats with such lesions received continuous intraventricular infusions of NGF or vehicle. Unlesioned rats with a sham operation were studied as controls. After learning sessions, a dialysis probe was implanted in the CA3 hippocampal region. In addition, brain sections were stained for synaptophysin immunoreactivity. In rats undergoing surgical procedures similar to those in the behavioral study, brains were processed for acetylcholinesterase (AChE) histochemistry. NGF-treated rats showed partial amelioration of lesion-associated hippocampal acetylcholine (ACh) efflux deficits and fixed-interval schedule learning impairment compared with vehicle-treated rats. Histochemical, immunohistologic, and microdensitometric analyses confirmed greater density of AChE-positive fibers and synaptophysin immunoreactivity in CA3, in NGF-treated rats relative to vehicle-treated rats, although not as great as in sham-operation rats, indicating partial recovery in NGF-treated rats. These results suggest that enhanced performance of the learning task with NGF treatment was related to improved hippocampal cholinergic function: specifically, increased cholinergic neurotransmission resulting from NGF effects on cholinergic neurons and presynaptic terminals.

Similarities and differences between Alzheimer's disease and vascular dementia from the viewpoint of nutrition

Dietary habits were compared in patients with Alzheimer's disease (AD) and those with vascular dementia (VaD). Twenty-seven patients with AD, 15 patients with VaD, and 49 age-matched controls were enrolled. Nutritional status was assessed using a semiquantified food-frequency questionnaire. Dietary habits were very similar in male patients with AD and VaD. Both groups had significantly higher energy intake than their energy demands: +25% for AD and +35% for VaD, respectively. However, major sources of energy were different: grains and animal fats for AD versus only grains for VaD. Calculation of nutrients revealed excess intake of n-6 polyunsaturated fatty acids (PUFA) and relative deficiencies of multiple vitamins including antioxidants, vitamin C and carotene, and the vitamin B group. In contrast, dietary habits in female patients with AD differed significantly from those of male patients. Female patients consumed significantly lower amounts of fish and green vegetables. Calculation of nutrients showed absolute deficiencies of n-3 PUFA, multiple vitamins, and minerals. Our results show that AD and VaD are similar from the viewpoint of nutrition, except for the higher consumption of animal fats for AD patients, probably reflecting Westernization of dietary habits in recent years. Nutrition may be relevant to the pathogenesis of dementia through many processes. Higher intake of energy and lower intake of antioxidants may exaggerate the process of dementia through oxidative stress. Excessive amounts of n-6 PUFA or deficiency of n-3 PUFA may cause chronic inflammation, platelet aggregation, or endothelial dysfunction of microvasculature. Nutrition may be useful for preventing dementia, although gender-specific differences must be taken into account.

Intramolecular epitope spreading among anti-caspase-8 autoantibodies in patients with silicosis, systemic sclerosis and systemic lupus erythematosus, as well as in healthy individuals

Dysregulation of apoptosis through the Fas-Fas ligand pathway is relevant in autoimmune disease onset. We recently reported elevated serum levels of sFas in patients with silicosis, systemic sclerosis (SSC) and systemic lupus erythematosus (SLE), and proposed a block of apoptosis in the pathogenesis. The disturbance of apoptosis in lymphocytes including autoreactive clones could induce autoantibody production. Since autoantibodies directed against unknown antigens are present in the sera of these patients, the sera samples were examined for the presence of autoantibodies directed to caspase-8. Using Western blotting, autoantibodies against caspase-8 were detected in healthy individuals and in over 60% of patients. Using epitope mapping employing 12 amino acid polypeptides with SPOTs system, a minimum of 4 epitopes and a maximum of 13 were found, which implied that epitope spreading was in progress. It is noteworthy that two important catalytic cystein residues were included within the epitopes; firstly the active site cystein Cys287, and secondly Cys360 located in the unique pentapeptide motif QACQG. Using recombinant human caspase-8 linked protein chip array, autoantibodies were identified and molecular weight determined. The antibodies were mainly IgG; 80% were subclass IgG1(lambda); 20% were IgG4(kappa). Despite the ratio of human light chain kappa:lambda = 2:1, the predominance of IgG1(lambda) is noticeable. Anti-caspase-8 autoantibodies are detectable in healthy individuals and in patients suffering silicosis, SSc or SLE. A few epitopes were detected in healthy individuals compared to those suffering autoimmune diseases, indicating the intramolecular epitope spreading. Relationship of autoantibodies and the clinical background of the patients requires clarification.

Long-term synaptic alteration in the rat hippocampal CA3 field following an entorhinal cortex lesion

The entorhinal cortex is a key initial relay for cortical input to the hippocampus. To better understand hippocampal dysfunction resulting from early entorhinal cortex involvement in Alzheimer's disease, we stereotaxically injected ibotenic acid to produce unilateral entorhinal cortex lesions in rats. We then serially examined the CA3 hippocampal region by neuronal counts, histochemistry for acetylcholinesterase, and synaptophysin immunohistochemistry. Over 12 months, the neuronal counts did not change. Acetylcholinesterase-positive fibers were persistently but non-progressively beginning at 3 months. Synaptophysin immunoreactivity progressively declined over 12 months. Since much of the entorhinal cortex output proceeds to CA3 via the dentate gyrus, transsynaptic degeneration is suspected.

Different distribution of HLA class II alleles in anti-topoisomerase I autoantibody responders between silicosis and systemic sclerosis patients, with a common distinct amino acid sequence in the HLA-DQB1 domain

Autoantibodies against DNA topoisomerase I (anti-topo I) have been reported to be specific to systemic sclerosis (SSc), however, anti-topo I was detected in patients with silicone breast implants, SLE without features of SSc, and rheumatic diseases. We detected anti-topo I positive silicosis patients without any symptoms of autoimmune diseases. The correlation between anti-topo I autoantibody responses and HLA class II has been established. HLA-DRB1*1502; DQB1*0601 has been reported to be the most frequent anti-topo I associated haplotype among Japanese SSc patients. In this study, haplotype HLA-DR15; DQ6 was detected in all 4 anti-topo I positive Asian Japanese SSc patients randomly selected. Furthermore, HLA-DQB1*0402 was identified in 3 of 4 anti-topo I positive silicosis patients. These findings coincide with the results of a previous study, in which all 4 Japanese patients with anti-topo I had the DQB1*04 alleles, whereas no studies among Caucasian-Americans, African-Americans and Choctaw Indians found the involvement of DQB1*04. We investigated common features among various DQB 1 alleles. HLA-DQB I with a distinct characteristic is clearly involved in the anti-topo I response irrespective of ethnic groups, the main disease, or silica exposure. A common positioning of distinct amino acids, (i.e. positions 14, 30, 57 and 77 of the DQbeta1 domain are methionine, tyrosine, aspartic acid and threonine, respectively,) seems to be associated with anti-topo I response. The above-mentioned amino acid sequence is detected in alleles *0301, *0303, *0306, *0401, *0402, *0601 and *0602.

Anti-HER2-antibody enhances irradiation-induced growth inhibition in head and neck carcinoma

To explore the antiproliferative effects of rhumAbHER2 on head and neck squamous carcinoma cell (HNSCC) lines and breast cancer cell lines (BCCLs) and to evaluate the combined effects with irradiation, 2 human HNSCC lines and 2 BCCLs were exposed to rhumAbHER2 with or without irradiation. The results showed that combined treatment enhanced the growth and colonization inhibitory effects of rhumAbHER2 or irradiation. Interestingly, the apoptotic cell fraction produced by irradiation disappeared on combined treatment. This disappearance was associated with repression of p53 and Bax upregulation induced by irradiation, but conservation of the upregulation of p27. Based on these results, rhumAbHER2 and irradiation may be a new strategy for treating HNSCC and breast cancers. In addition, the upregulation of cyclin-dependent kinase inhibitors by rhumAbHER2 may occur upstream of irradiation-induced p53 upregulation.

[Malignant syndrome caused by a combination of bromperidol and donepezil hydrochloride in a patient with probable dementia with Lewy bodies]

The patient was a 68-year-old man with a 1-year history of delusions related to well-formed and detailed visual hallucinations. Bromperidol 12 mg was prescribed to treat his symptoms. After a diagnosis of dementia of Alzheimer's type was suspected, the patient received donepezil hydrochloride 5 mg. One week later, the patient's Parkinsonism deteriorated. One month later, the patient developed radical edema of the eyelids and the anterior neck, hypoproteinemia, and severe anteflexion of the body. One and a half months later, the patient developed malignant syndrome. His medication was discontinued and parenteral nutrition was started. The patient recovered from his malignant syndrome. However, 1 month later, his Parkinsonism had not improved. The patient received levodopa to treat his Parkinsonism and his symptoms subsequently improved. The hallucinations and systematized delusions returned. The patient's cognitive impairment deteriorated on one side. The aggravation of extrapyramidal symptoms and the development of malignant syndrome were believed to have been caused by the combination of bromperidol and donepezil hydrochloride and poor nutrition. Caution should be exercised when prescribing an antipsychotic drugs with donepezil hydrochloride.

Cell cycle analysis and expression of cell cycle regulator genes in myeloma cells overexpressing cyclin D1

Among the recently discovered myeloma-specific gene alterations associated with chromosomal translocations, cyclin D1/PRAD1/Bcl-1 overexpression caused by t(11;14)(q13;q32) is considered to be the most frequent in myeloma patients and cell lines, and may be a prognostic factor clinically. To elucidate the cellular biological role of overexpressed cyclin D1 in myeloma cells, we examined the mRNA expression levels of cell cycle regulators including three cyclin Ds, cyclin-dependent kinase inhibitors (CDK-Is) and accelerators. Cyclin D1 overexpression was clearly demonstrated in the lines with abnormal 11q13 and associated with overexpression of S and G2 accelerator genes. The cyclin D1-overexpressing lines tended to have a shortened G1 phase compared with the non-expressing lines. In addition, artificial silencing using antisense oligonucleotides for cyclin D1 suppressed the growth rate of some but not all cyclin D1-overexpressing cells. These results indicate that overexpression of cyclin D1 caused by cytogenetic abnormalities may make cells progress through the cell cycle rapidly, but it seems that other factors such as cyclin D2 and translocation-related genes affect the cell cycle progression in myeloma cells.

Factors associated with mortality in patients with early-onset Alzheimer's disease: a five-year longitudinal study

To identify neuropsychiatric and somatic factors related to survival in early-onset Alzheimer's disease, we longitudinally studied 108 patients (35 male, 73 female) with early-onset Alzheimer's disease who were 46 to 64 years old at onset and 50 to 69 years old when diagnosed at our institution. A five-year follow-up, 30 patients had died. Pneumonia was the most common cause (73%), followed by malignancy (20%) and heart disease (7%). Kaplan-Meier survival curves showed a lower survival rate in patients with early-onset Alzheimer's disease than in age- and sex-matched life-table data in Japan. In Cox proportional hazards analysis, male gender, early disease onset, concurrent physical illness at time of diagnosis, and a low mini-mental state examination score increased the likelihood of death in patients with early-onset Alzheimer's disease. Our study confirmed that these patients have considerable excess mortality and a different pattern of cause of death than in the general population. Gender, age at onset, physical illness, and cognitive function strongly influenced survival. These factors may be predictors of mortality in patients with early-onset Alzheimer's disease that are useful in counseling patients and their families.

Establishment of CD7+ human myeloma sister cell lines, KMS-21-PE and KMS-21-BM, carrying t(11;14) and t(8;14)

Two new human myeloma cell lines were established from pleural effusion and bone marrow malignant cells derived from a single patient, who manifested hyperammonemia associated with multiple myeloma, and these were characterized. Both lines possess t(11;14)(q13;q32) and t(8;14)(q24;q32) reciprocal translocations and overexpress cyclin D1, but not c-myc. Human myeloma lines including these new lines produced and secreted excess ammonia into culture medium more than non-myelomatous hematological cell lines. In addition, these two lines were revealed to have high surface CD7 expression correlated with relatively high mRNA expression by MP-RT-PCR. Among 8 human myeloma lines, half of them revealed significant surface expression of CD7 and a positive correlation between expression levels of protein and message. CD7 message was also detected in surface negative lines. Consequently, there may be posttranslational regulation of the CD7 molecule, whose cellular biological role in expressing cells has not been elucidated.

Antidesmoglein autoantibodies in silicosis patients with no bullous diseases

BACKGROUND

Pemphigus is an autoimmune bullous disease characterized by the presence of antidesmoglein autoantibodies. However, the mechanism of its autoantibody production remains unknown. In previous reports, we have described rare cases of pemphigus and pemphigoid associated with silicosis. It is well known that during long-term silicosis, some autoimmune diseases, such as systemic sclerosis, systemic lupus erythematosus or rheumatoid arthritis, can occur.

OBJECTIVE

The aim of this study was to explore the presence of pemphigus or pemphigoid autoantibodies in silicosis patients without clinical bullous diseases or collagen diseases.

METHOD

The presence of pemphigus antibodies was examined in 54 silicosis patients with no associated bullous diseases, using immunofluorescence, the enzyme-linked immunosorbent assay (ELISA) for desmoglein 1 and 3, and immunoblotting methods. In the antibody-positive cases, HLA genotyping of peripheral lymphocytes was performed with PCR-RFLP.

RESULTS

Seven out of the 54 patients were found to be positive for pemphigus antibodies and 1 for bullous pemphigoid by immunofluorescence. In addition, by ELISA, 6 patients were found to be positive against the desmoglein 1 antigen, 2 against the desmoglein 3 antigen and 2 against both desmoglein 1 and desmoglein 3.

CONCLUSION

The results of the present study strongly suggest the occurrence of pemphigus and pemphigoid autoantibodies in patients with silicosis. It remains unclear whether such patients will develop an autoimmune bullous disease in the future. Accordingly, long-term follow-up of antibody-positive patients is required.

Autoantibodies detectable in the sera of silicosis patients. The relationship between the anti-topoisomerase I antibody response and HLA-DQB1*0402 allele in Japanese silicosis patients

Eighty-one Japanese silicosis patients and 66 healthy volunteers were analyzed for autoantibodies by ELISA, and HLA-genotyping using the PCR-RFLP method was performed. Anti-topoisomerase I (anti-topo I) autoantibodies were detected in seven patients without any clinical features of autoimmune diseases such as progressive systemic sclerosis (PSS), although anti-topo I have been mostly reported in PSS patients. Antibodies directed to RNP, ssDNA, dsDNA and cent-B were not detected among the anti-topo I positive patients. The indirect immunofluorescent staining pattern of Hep-2 cells with the sera of anti-topo I positive silicosis patients demonstrated the typical mode of anti-topo I autoantibodies observed in the patients with PSS. The allelic frequency of HLA-DQB1*0402 was significantly higher in anti-topo I positive patients (28.6%) than in anti-topo I negative patients (1.5%, P < 0.001) or healthy controls (0.8%, P<0.001). HLA-DQB1*0301, DQB1*0601 and DPB1*1801 alleles were more frequently detected in anti-topo I positive patients than in the patients without anti-topo I or in healthy volunteers, but no significant difference was observed. DQB1 allele is associated with the induction of anti-topo I autoantibodies in Japanese silicosis patients, but the allele is not the same as in Caucasian PSS patients. Another allele (DQB1*0402) plays an important role in Japanese silicosis patients. The most important factor to induce anti-topo I autoantibodies seems not to be the type of alleles themselves, but the position of some specific amino acid residues in the DQ beta first domain. These findings will be useful for preventing occupational autoimmune diseases.

Expression and in vitro modification of parathyroid hormone-related protein (PTHrP) and PTH/PTHrP-receptor in human myeloma cells

To elucidate the role of PTHrP in myeloma, we examined the expression levels of PTHrP and its receptor in human myeloma cell lines and clinical specimens from 13 myeloma cases. In vitro modification of PTHrP expression and production induced by TGF-beta and PMA in PTHrP expressing myeloma cell lines was also investigated. PTHrP expression was detected in six out of seven myeloma cell lines with an inverse correlation with the expression of its receptor, and in 10 out of 13 clinical specimens in varying degrees. The PTHrP expression and secretion into culture medium were enhanced by supplemental TGF-beta and PMA. PMA also seemed to affect PTHrP upregulation via TGF-beta activation. The fundamental role of PTHrP in bone lesions and hypercalcemia in myeloma may be important to consider even during the initial phase of the disease and particularly in the progression of bone complications with hypercalcemia.

Biological effects of asbestos fibers on human cells in vitro--especially on lymphocytes and neutrophils

Biological effects of asbestos fibers were reviewed in relation to the polyclonal activation of human lymphocytes and to the release of free radicals from human neutrophils in vitro. Chrysotile, crocidolite, and amosite asbestos activate CD4+ T lymphocytes polyclonally, followed by activation-induced cell death (a type of apoptosis). The activation is HLA class II dependent, and certain Vbeta repertoire, e.g. Vbeta 5.3, are detected among the fractionated T cells with a high Ca++ level that had been stimulated by asbestos fibers. These observations support the possibility that asbestos acts as a superantigen, and that asbestos stimulate lymphocytes repeatedly in vivo. It has been reported that asbestos-induced cytotoxicity can be suppressed by the scavengers of superoxide or hydroxyl radical. Some of these scavengers such as dimethylsulfoxide (DMSO) or retinoic acid are known as inducers of cell differentiation. The biological functions of DMSO for cell differentiation of HL-60 cells to neutrophils are suppressed by co-culturing of crocidolite asbestos, because DMSO reacts with the hydroxyl radical released after the stimulation with crocidolite and spent itself. Superoxide dismutase (SOD) inhibited the effects of crocidolite, reacting rapidly with *O2- before the secondary release of *OH. It seems to be probable that asbestos fibers, especially crocidolite, suppress the tissue cell differentiation by releasing free radicals and by wasting inducers of cell differentiation as radical scavengers.

No evidence for an association between the Glu298Asp polymorphism of the NOS3 gene and Alzheimer's disease

Recently a significant association of a missense mutation (Glu298Asp) of the endothelial nitric oxide synthase (NOS3) gene with late-onset Alzheimer's disease (LOAD) was reported. We tried to replicate this finding in a Japanese sample of 121 patients with LOAD, 51 with early-onset AD (EOAD), and 165 medical controls. However, the genotype and allelic distributions for the Glu298Asp polymorphism were similar for these three groups, suggesting that the Glu298Asp polymorphism of the NOS3 gene has no relevance to the development of AD in Japanese.

A novel polymorphism of the brain-derived neurotrophic factor (BDNF) gene associated with late-onset Alzheimer's disease

Several lines of evidence have suggested altered functions of the brain-derived neurotrophic factor (BDNF) in the pathogenesis of neurodegenerative diseases including Alzheimer's disease (AD). In the search for polymorphisms in the 5'-flanking and 5'-noncoding regions of the BDNF gene, we found a novel nucleotide substitution (C270T) in the noncoding region. We performed an association study between this polymorphism and AD in a Japanese sample of 170 patients with sporadic AD (51 early-onset and 119 late-onset) and 498 controls. The frequency of individuals who carried the mutated type (T270) was significantly more common in patients with late-onset AD than in controls (P = 0.00004, odds ratio: 3.8, 95% CI 1.9-7.4). However, there was no significant difference in the genotype distribution between the patients with early-onset AD and the controls, although this might be due to the small sample size of the early-onset group. Our results suggest that the C270T polymorphism of the BDNF gene or other unknown polymorphisms, which are in linkage disequilibrium, give susceptibility to late-onset AD. We obtained no evidence for the possible interactions between the BDNF and apolipoprotein E (APOE) genes, suggesting that the possible effect of the BDNF gene on the development of late-onset AD might be independent of the APOE genotype.

Expression and production of interleukin 10 in human myeloma cell lines

Recent investigations of the cytokine network surrounding myeloma cells have disclosed the importance of gp130-related cytokines including interleukin (IL)-6 for myeloma cell survival and proliferation, identification of IL-10 as a growth factor for myeloma cells, the close relationship between IL-10 and the receptors for gp130-related cytokines, and the growth enhancement effect of IL-11 and IL-7 on myeloma cells. In this study, IL-10 production was observed in three out of seven human myeloma cell lines examined and five (including three producing lines) out of 10 lines exhibited mRNA expression of IL-10. The IL-10 mRNA expression was also enhanced in approximately one third of primary specimens, whereas the IL-10 receptor (R) expression was not changed compared with that of normal component marrow controls. However, reverse transcription-polymerase chain reaction (RT-PCR) assay of various cytokines and their receptors showed no particular association with IL-10-producing myeloma lines compared with non-producing lines. Supplementing exogenous IL-10 or neutralization of the IL-10 signal by anti-IL-10 monoclonal antibody (mAb) in a culture conditions did not significantly affect myeloma cell growth regardless of expression of IL-10 or its receptor (IL-10R). However, supplement of anti-IL-10 mAb caused upregulation of certain genes such as IL-11, leukaemia inhibitory factor receptor (LIFR) and syndecan-1 in IL-10R-expressing cell lines. These findings indicate that the cytokine network surrounding myeloma cells is complicated and variable. In addition, IL-10 may modify this network and the cellular biological properties of myeloma cells rather than cell proliferation.

No genetic association between alpha-2 macroglobulin I1000V polymorphism and Japanese sporadic Alzheimer's disease

Alpha-2 macroglobulin (A2M) is a serum pan-protease inhibitor that is related with the pathogenesis of Alzheimer's disease (AD) through its ability to mediate amyloid beta degradation. Recently, it has been reported that the I1000V polymorphism in A2M gene might increase the risk of AD. In the present study, we investigated this mutation in 95 healthy controls and in 111 sporadic AD cases by polymerase chain reaction-restriction fragment length polymorphism method in order to study this hypothesis in the Japanese AD population. Allelic frequencies with the I1000V polymorphism in the gene were 7.4 and 6.8% in the control and AD groups, respectively. Our results failed to demonstrate an association between this polymorphism and Japanese sporadic AD, and the A2M I1000V mutation does not seem to be a risk factor per se for sporadic AD.

Cellular biological differences between human myeloma cell lines KMS-12-PE and KMS-12-BM established from a single patient

To clarify cellular biological varieties of myeloma cells, biological differences were analyzed between 2 human myeloma cell lines, KMS-12-PE and KMS-12-BM, derived from pleural effusion and bone marrow, respectively, of a single patient. Although both lines were considered to be derived from the same clone because both had the same chromosomal marker and immunoglobulin H rearrangement, several biological differences were noted. CD11a and CD20 were highly expressed in the KMS-12-BM line, whereas the KMS-12-PE line showed a higher expression of CD7 and CD95/Fas. Although growth was stimulated in KMS-12-BM by interleukin-6 and interferon-alpha, it was inhibited in KMS-12-PE. In addition, apoptosis inhibitors Bcl-2 and Bcl-X(L) were highly expressed in KMS-12-BM cells. Because KMS-12-PE was cultivated 2 months before KMS-12-BM, these differences might be related to their origin (pleural effusion and bone marrow) or the phases of disease progression. However, these biological differences may help clarify myeloma cell biology and lead to improvement in treatment for myeloma patients.

Depression in multiple system atrophy: a case report

A 53-year-old woman who developed depression as the first symptom of multiple system atrophy was treated. Depression was followed successively by autonomic failure, parkinsonism and cerebellar ataxia. Treatment with L-DOPA, L-threo-DOPS, and thyroid releasing hormone was associated with improvement of autonomic failure and parkinsonism. As for depression, scores on the Zung scale and the Hamilton scale improved from 58 to 49 and from 30 to 22, respectively, This case is remarkable in that depression preceded neurologic dysfunction and was managed successfully by antiparkinsonian medication. A common underlying disturbance may be responsible for the depression and neurologic dysfunction in multiple system atrophy.

[Fas-Fas ligand system in silicosis patients]

The exposure to silica and related substances such as silicate (e.g. chrysotile asbestos; 3MgO.2SiO2.H2O) or silicone (-R2Si-O-)n, used in plastic surgery, has been known to induce autoimmune diseases. The pathogenesis of autoimmunity induced by such environmental factors, however, needs to be clarified. On the other hand, details about the relationship between autoimmunity and defective functioning of the Fas-Fas ligand system have been analyzed. In this report, we intend to summarize our results which suggest a suppressed apoptosis through the Fas-Fas ligand system in silicosis patients, and to speculate on the effects of silica on inappropriate cell survival which could induce the development of autoimmune reactions. We observed elevated levels of serum sFas and an increased expression of sFas mRNA in silicosis patients. sFas instead of membranous Fas binds competitively to the Fas ligand, and consequently, reduces the apoptosis of Fas positive cells. In addition, we observed polyclonal activation of human T cells by silica and silicate in vitro. In such cases, many autoreactive clones could be activated simultaneously. From these results, silica and silicate could play an important role in inducing autoimmune reactions by (1) repeated polyclonal activation of human T cells and (2) the suppression of apoptosis inducing the release of sFas into the sera of the patients.

Deficiency in mitochondrial aldehyde dehydrogenase increases the risk for late-onset Alzheimer's disease in the Japanese population

Mitochondrial aldehyde dehydrogenase 2 (ALDH2) deficiency is caused by a mutant allele in the Mongoloids. To examine whether genetic constitutions affecting aldehyde metabolism influence the risk for late-onset Alzheimer's disease (LOAD), we performed a case-control study in the Japanese population on the deficiency in ALDH2 caused by the dominant-negative mutant allele of the ALDH2 gene (ALDH2*2). In a comparison of 447 patients with sex, age, and region matched nondemented controls, the genotype frequency carrying the ALDH2*2 allele was significantly higher in the patients than in the controls (48.1% vs 37.4%, P = 0.001). Logistic regression analysis indicates that carriage of the ALDH2*2 allele is an independent risk for LOAD of the epsilon4 allele of the apolipoprotein E gene (APOE-epsilon4) (P = 0.002). Moreover, the odds ratio for LOAD in carriers of the ALDH2*2 allele was almost twice that in noncarriers, irrespective of status with regard to the APOE-epsilon4 allele. Among patients homozygous for the APOE-epsilon4 allele, age at onset of LOAD was significantly lower in those with than without the ALDH2*2 allele. In addition, dosage of the ALDH2*2 allele significantly affected age at onset of patients homozygous for the APOE-epsilon4 allele. These results indicate that the ALDH2 deficiency is a risk for LOAD, synergistically acting with the APOE-epsilon4 allele.

Alzheimer's disease and 5-HTTLPR polymorphism of the serotonin transporter gene: no evidence for an association

Recently two independent research groups consistently reported a significant association between the serotonin transporter (5-HTT) gene and late-onset sporadic Alzheimer's disease (AD). They found that the "short" allele of the 5-HTT gene-linked polymorphic region (5-HTTLPR), which is associated with reduced transcriptional activity of the gene, increases the risk of developing late-onset AD. The present study tried to replicate this finding in a Japanese sample. We genotyped 41 patients with early-onset AD (<65 years), 82 with late-onset AD, and 336 controls. There was no significant difference in genotype or allele distribution between either patient group and controls in our sample, suggesting that the 5-HTTLPR does not play a major role in the pathogenesis of AD in Japanese.

Detection of alternatively spliced variant messages of Fas gene and mutational screening of Fas and Fas ligand coding regions in peripheral blood mononuclear cells derived from silicosis patients

Silicosis is clinically characterized not only by respiratory disorders but by immunological abnormalities such as the appearance of autoantibodies and complications of autoimmune diseases. Dysregulation of apoptosis, particularly in the Fas/Fas ligand (FasL) pathway, has been considered to play a role in the pathogenesis of autoimmune diseases. It has been found that serum soluble Fas (sFas) levels are elevated in silicosis patients (SIL) and the sFas message is dominantly expressed in peripheral blood mononuclear cells (PBMC) derived from these individuals. In the present study, one tried to detect alternatively spliced variant messages including typical sFas message and found four that were highly and frequently expressed, and which possess a signal peptide domain, but not transmembrane and signal transducing domains, in PBMC derived from SIL. Functional mutations were not detected in Fas and FasL genes in silicosis PBMC. Still, alternative spliced variants of the Fas gene including typical sFas message appear to play an important role in the immunological dysregulation in SIL.

[A case of primary aldosteronism presenting hypokalemic myopathy induced by benidipine hydrochloride; a dihydropyridine calcium channel blocker]

We report a 46-year-old man with primary aldosteronism presenting hypokalemia, periodic paralysis and hypokalemic myopathy whose clinical course paralleled with the dosage of benidipine hydrochloride, a dihydropyridine calcium channel blocker (DHP-CCB), administered for the treatment of hypertension. To see relations between DHP-CCB and episodes of motor weakness in patients with primary aldosteronism, we surveyed retrospectively the history of motor weakness and anti-hypertensive drugs in 14 consecutive cases with primary aldosteronism in our institute. Five patients out of 11 cases (45.5%) who had received DHP-CCB experienced muscle weakness, however, the rest of three patients receiving other anti-hypertensive drug had not experienced weakness. Though, less attention has been paid as thiazide diuretics, it is reported that DHP-CCB also induces hypokalemia through several mechanisms. However, the occurrence of motor weakness by DHP-CCB is very rare. Our results show that primary aldosteronism should be taken into account when we encounter patients manifesting episodic motor weakness by the use of DHP-CCB.

Estrogen receptors in human myeloma cells

It has recently been reported that the human myeloma cell line U266 proceeds to undergo apoptosis after cultivation with the antiestrogen tamoxifen, thus raising the possibility that antiestrogens may be candidates for use in myeloma therapy. To obtain basic information on the effects of antiestrogens on myeloma cells, we investigated the mRNA expression levels of estrogen receptor (ER)-alpha, ER-beta, and coactivators and corepressors in nine human myeloma cell lines and compared them with those of seven human breast cancer cell lines including four ER-positive and three ER-negative lines. The alterations in cell growth and mRNA expression of the target genes of ER or those of cytokines in the myeloma lines by estradiol or antiestrogens (tamoxifen and toremifene) were also investigated. In addition, effects on membrane Fas expression, appearance of apoptosis, and cell cycle perturbation were analyzed. It was revealed that ER-beta and corepressors were dominantly expressed in myeloma cells, and antiestrogens induced growth inhibition through apoptosis mediated by a Fas-related pathway and G1 arrest of the cell cycle in myeloma cell lines.

Over-expression of the decoy receptor 3 (DcR3) gene in peripheral blood mononuclear cells (PBMC) derived from silicosis patients

Dysregulation of apoptosis, particularly in the Fas/Fas ligand (FasL) pathway, is considered to be involved in the pathogenesis of autoimmune diseases such as systemic lupus erythematosus (SLE). Recently, a soluble decoy receptor, termed decoy receptor 3 (DcR3), that binds FasL and inhibits FasL-induced apoptosis, has been identified. Silicosis is clinically characterized not only by respiratory disorders but by immunological abnormalities. We have found that serum soluble Fas (sFas) levels are elevated in silicosis patients and that sFas message is dominantly expressed in PBMC derived from these patients. This study examined DcR3 gene expression in PBMC derived from patients with silicosis, SLE, or progressive systemic sclerosis (PSS), and compared it with that in healthy volunteers (HV). The relative expression level of the DcR3 gene was examined in PBMC derived from 37 patients with silicosis without clinical symptoms of autoimmune disease, nine patients with SLE, 12 patients with PSS, and 28 HV using the semiquantitative multiplex-reverse transcriptase-polymerase chain reaction (MP-RT-PCR). The correlation between the relative expression level of the DcR3 gene and multiple clinical parameters for respiratory disorders and immunological abnormalities in individuals with silicosis was analysed. The DcR3 gene was significantly over-expressed in cases of silicosis or SLE when compared with HV. In addition, the DcR3 relative expression level was positively correlated with the serum sFas level in silicosis patients. It is unclear, however, whether over-expression of the DcR3 gene in silicosis is caused by chronic silica exposure, merely accompanies the alteration in Fas-related molecules, or precedes the clinical onset of autoimmune abnormalities. It will be necessary to study these patients further, establish an in vitro model of human T cells exposed recurrently to silica compounds, and resolve whether the increase in DcR3 mRNA expression is a cause or consequence of disease.

Expression of fibroblast growth factor and FGF-receptor family genes in human myeloma cells, including lines possessing t(4;14)(q16.3;q32. 3) and FGFR3 translocation

Recently several chromosomal translocations involved in myeloma cases and myeloma cell lines; i.e., t(11;14)(q13;q32), t('8;14)(q24;q32), t(4;14)(q16.3;q32.3), t(6;14)(p25;q32), and t(14;16)(q32.3;q23), have been identified. These translocations are considered to dysregulate genes which may be concerned with myelomagenesis; i.e., PRAD1/cyclin D1, the c-myc oncogene, FGFR3 (fibroblast growth factor receptor 3), MMSET (multiple myeloma SET domain), MUM1 (multiple myeloma oncogene 1)/IRF4 (interferon regulatory factor 4), and the c-maf oncogene, respectively. However, the cellular biological roles of these genes have not yet been elucidated in myeloma cells. Because two of the seven human myeloma cell lines which were established at Kawasaki Medical School, Okayama, Japan, KMS-11 and KMS-18, have been proven to possess t(4;14)(q16.3;q32.3), we studied the expression levels of the FGFR3 gene in these seven cell lines and 13 primary myeloma specimens. The expression levels of 12 known FGF family genes (FGF-1 to 12) and 4 FGFR genes (FGFR1 to 4) were also examined in seven cell lines. In addition, the growth status of the KMS-11 and KMS-18 lines with FGF-1 or anti-FGF-4 neutralizing monoclonal antibody (MoAb) supplementation was investigated because FGF-1 and 4 are known as the principal ligands for FGFR3. FGFR3 overexpression was observed in both of the cell lines possessing t(4;14)(q16.3;q32.3) and in 3 of 13 case specimens. Anti-FGF-4 neutralizing MoAb caused significant growth inhibition in these two cell lines possessing t(4;14)(q16.3;q32.3). These findings indicate that t(4;14) (q16. 3;q32.3) may provide myeloma cells with a growth advantage via an autocrine mechanism between FGFR3 and FGF-4.

Man-made mineral fibers induce apoptosis of human peripheral blood mononuclear cells similarly to chrysotile B

The aim of this study was to investigate whether man-made mineral fibers (MMMF) induce apoptosis of human peripheral blood mononuclear cells (PBMC), as we recently demonstrated for chrysotile B. In vitro cultivation of PBMC with various MMMF as well as chrysotile B clearly produced apoptotic cells. The alteration of the expression for apoptosis related genes at the mRNA level during in vitro cultures of PBMC with various MMMF revealed upregulation of Flice and Apaf-1 genes and down regulation of TNF receptor 1 and Bid genes. These results indicate that MMMF induce apoptosis of PBMC in a similar manner to chrysotile B. However, the process may be mediated not only by the Fas-related apoptotic pathway but also a mitochondrial pathway. Thus, one should be aware that respiratory and immunological abnormalities may occur in workers who are exposed to MMMFs.

Serum levels of soluble Fas ligand in patients with silicosis

Certain patients with silicosis have been reported to exhibit immunological abnormalities such as the appearance of antinuclear antibodies and the occurrence of autoimmune diseases. Fas ligand (FasL) is a type II membrane protein which induces apoptosis by binding to its membrane receptor, Fas. FasL is converted to a soluble form by a metalloproteinase-like enzyme. We have already found serum soluble Fas (sFas) levels in silicosis patients as well as in patients with systemic lupus erythematosus (SLE) to be significantly higher than those in healthy volunteers. To examine further the role of the Fas/FasL system in silica-induced immunological abnormalities, we investigated serum soluble FasL (sFasL) levels in silicosis patients with no clinical symptoms of autoimmune diseases, using ELISA for sFasL. Although the serum sFasL levels in patients with SLE were significantly higher than those in healthy volunteers and showed a slight positive correlation with serum sFas levels, those in silicosis patients exhibited no significant difference from those in healthy volunteers, and there was no correlation with serum sFas levels. However, sFasL levels were elevated in silicosis patients with slight dyspnoea or normal PCO2 among various clinical parameters of silicosis. It may be speculated that the immunological disturbances presented by the abnormalities of apoptosis-related molecules in silicosis patients do not occur with a similar degree of respiratory involvement. Further studies are required to clarify which kinds of factors are involved in silicosis patients who exhibit immunological abnormalities.

5-HT(2A/2C) receptor agonist-induced increase in urinary isatin excretion in rats: reversal by both diazepam and dexamethasone

Isatin, a stress-related biological substance, increases in rat urine in association with elevated catecholamine biosynthesis during stress. The goal of this study was to unravel how the biosynthetic pathway of isatin is related to stress response. The importance of the serotonergic compounds in anxiety, which is the major emotional process of stress response, has emerged. m-Chlorophenylpiperazine (m-CPP), a 5-HT(1A/1B/2A/2C) receptor agonist, and (+/-)-1-(4-iodo-2,5-dimethoxyphenyl)-2-aminopropane hydrochloride [(+/-)-DOI], a 5-HT(2A/2C) agonist, both of which have anxiogenic properties, induced a marked increase in 24-hr urinary isatin excretion, whereas neither 1-(m-chlorophenyl)-biguanide (m-CPBG), a 5-HT3 agonist, nor 2-methyl-5-HT, a 5-HT(3,4) agonist, affected urinary isatin excretion. 5-HT(2A/2C) receptor antagonists such as ketanserin and ritanserin prevented the increase in urinary isatin excretion induced by the 5-HT(2A/2C) receptor agonist m-CPP. These findings are the first to provide evidence that pharmacological substances cause increases in urinary isatin excretion via specific 5-HT receptors, probably 5-HT(2A/2C) receptors. In addition, both the synthetic glucocorticoid dexamethasone and diazepam prevented the m-CPP-induced increase in urinary isatin excretion. These observations suggest that the mechanism by which m-CPP elicits enhancing effects on urinary isatin excretion has something in common with stress response involving activation of hypothalamic CRF cells and the sympathetic nervous system.