S100A8/A9 as a biomarker for synovial inflammation and joint damage in patients with rheumatoid arthritis

S100A8 and S100A9 are major leukocyte proteins, known as damage-associated molecular patterns, found at high concentrations in the synovial fluid of patients with rheumatoid arthritis (RA). A heterodimeric complex of S100A8/A9 is secreted by activated leukocytes and binds to Toll-like receptor 4, which mediates downstream signaling and promotes inflammation and autoimmunity. Serum and synovial fluid levels of S100A8/A9 are markedly higher in patients with RA than in patients with osteoarthritis or miscellaneous inflammatory arthritis. Serum levels of S100A8/A9 are significantly correlated with clinical and laboratory markers of inflammation, such as C-reactive protein, erythrocyte sedimentation rate, rheumatoid factor, and the Disease Activity Score for 28 joints. Significant correlations have also been found between S100A8/A9 and radiographic and clinical assessments of joint damage, such as hand radiographs and the Rheumatoid Arthritis Articular Damage score. In addition, among known inflammatory markers, S100A8/A9 has the strongest correlation with total sum scores of ultrasonography assessment. Furthermore, baseline levels of S100A8/A9 are independently associated with progression of joint destruction in longitudinal studies and are responsive to change during conventional and biologic treatments. These findings suggest S100A8/A9 to be a valuable diagnostic and prognostic biomarker for RA.

The effects of antihypertensive drugs on bone mineral density in ovariectomized mice

The effects of several antihypertensive drugs on bone mineral density (BMD) and micro-architectural changes in ovariectomized (OVX) mice were investigated. Eight-week-old female C57/BL6 mice were used for this study. Three days after ovariectomy, mice were treated intraperitoneally with nifedipine (15 mg/kg), telmisartan (5 mg/kg), enalapril (20 mg/kg), propranolol (1 mg/kg) or hydrochlorothiazide (12.5 mg/kg) for 35 consecutive days. Uterine atrophy of all mice was confirmed to evaluate estrogen deficiency state. BMD and micro-architectural analyses were performed on tibial proximal ends by micro-computed tomography (micro-CT). When OVX mice with uterine atrophy were compared with mice without atrophy, BMD decreased (P < 0.001). There were significant differences in BMD loss between different antihypertensive drugs (P = 0.005). Enalapril and propranolol increased BMD loss in mice with atrophied uteri compared with control mice. By contrast, thiazide increased BMD in mice with uterine atrophy compared with vehicle-treated mice (P = 0.048). Thiazide (P = 0.032) and telmisartan (P = 0.051) reduced bone loss and bone fraction in mice with uterine atrophy compared with the control. Thiazide affects BMD in OVX mice positively. The reduction in bone loss by thiazide and telmisartan suggest that these drugs may benefit menopausal women with hypertension and osteoporosis.

Metformin downregulates Th17 cells differentiation and attenuates murine autoimmune arthritis

INTRODUCTION

This study was undertaken to determine whether metformin has anti-inflammatory effects in the collagen antibody-induced arthritis (CAIA) murine model. The effect of metformin on Th17 cell differentiation was also investigated.

METHODS

CAIA mice were treated with 100 and 150 mg/kg i.p. metformin (low- and high-dose groups, respectively). Arthritis activity and histological joint destruction were studied. Flow cytometry was used to (i) determine RORγt-expressing CD4+ percentages in draining axillary lymph nodes (ALNs) from metformin-treated and untreated mice with CAIA, (ii) determine Th17 percentages in splenic CD4+ T cells cultured ex vivo for 3 days in Th17-differentiation-inducing conditions, and (iii) determine the percentages of RORγt+CD4+ T cells when normal splenic T cells from DBA/1 mice were cultured in Th17-differentiation-inducing conditions together with various metformin doses. Western blot analysis was used to assess the intracellular signaling of the metformin-treated splenocytes.

RESULTS

Metformin attenuated both arthritis scores and bone destruction in CAIA mice, decreased the serum levels of the pro-inflammatory cytokines, TNF-α and IL-1, and reduced the number of RORγt+CD4+ T cells in the ALNs. Splenocytes from metformin-treated CAIA mice differentiated less readily into Th17 cells upon ex vivo stimulation. Metformin treatment of normal cells cultured in Th17-differentiation-inducing conditions decreased the number of RORγt-expressing CD4+ cells in a dose-dependent manner and downregulated STAT3 phosphorylation via the AMPK pathway.

CONCLUSIONS

Metformin had an anti-inflammatory effect on murine autoimmune arthritis due to the inhibition of Th17 cell differentiation. Metformin may have a possible therapeutic value for treatment of rheumatoid arthritis.

The paradoxical effects of TNF inhibitors on bone mineral density and radiographic progression in patients with ankylosing spondylitis

OBJECTIVES

To determine the longitudinal effects of TNF inhibitors on BMD and radiographic progression in patients with AS and to assess independent factors associated with increased BMD in the lumbar spine.

METHODS

Sixty-three patients with AS were included. Twenty-six patients were treated with TNF inhibitors and 37 were not. BMD in the lumbar spine and right femur was measured by DXA at baseline and 1 and 2 years later. Lumbar spine radiography was performed at baseline and after 2 years. Radiographic progression was scored using the Stoke AS Spinal Score (SASSS) and the modified SASSS. Univariate and multivariate linear regression analyses were performed to identify factors independently associated with spinal BMD increase.

RESULTS

BMD in the lumbar spine and total proximal femur of patients receiving TNF inhibitors increased consistently over 2 years compared with that in patients not receiving TNF inhibitors (P < 0.01 and P = 0.02), and treated patients showed increased SASSS scores (P = 0.05); however, syndesmophyte development was no different between the two groups. There was a significant difference in the change of SASSS in patients treated with both TNF inhibitors and bisphosphonates compared with those treated with TNF inhibitors alone (P < 0.01). TNF inhibitor therapy and the increase in SASSS were independently associated with increased lumbar spine BMD (P = 0.009 and P < 0.001).

CONCLUSION

TNF inhibitors appear to be associated with increased SASSS scores and improvements in BMD. Further prospective studies with larger subject numbers are needed to validate this paradoxical role of TNF inhibitors.

Tacrolimus treatment increases bone formation in patients with rheumatoid arthritis

Tacrolimus is a calcineurin inhibitor, and it is used for the treatment of rheumatoid arthritis (RA). It works by inhibiting nuclear factor of activated T cells and inducting immunosuppression. This study aims to evaluate the influence of tacrolimus on the bone metabolism of patients with RA. Twenty-eight RA patients in three centers received tacrolimus 3 mg once daily for 24 weeks. Blood samples for evaluating bone metabolism and cytokines were collected at Weeks 0 and 24. We measured the serum C-telopeptide of type I collagen (sCTx-I), osteocalcin and inflammatory cytokines. We analyzed the data using the Kruskal-Wallis test and Spearman's correlation. IL-2 and IL-6 were significantly decreased after the administration of tacrolimus (p = 0.027 and p = 0.024). There was no significant difference in the serum level of sCTx-I before and after treatment. The level of serum osteocalcin at Week 24 was significantly increased compared to the level at Week 0 (p = 0.002). The increase of osteocalcin was correlated with the reductions of IL-2 and IFN-γ (r = 0.405, p = 0.033 and r = 0.380, p = 0.046, respectively). Tacrolimus treatment increased bone formation markers in RA patients. This suggests that tacrolimus may play a role to inhibit bone erosion by increasing bone formation as well as improving the clinical symptoms of RA.

Impact of interleukin-21 in the pathogenesis of primary Sjögren's syndrome: increased serum levels of interleukin-21 and its expression in the labial salivary glands

INTRODUCTION

Interleukin (IL)-21 is a cytokine that controls the functional activity of effector T helper cells and the differentiation of Th17 cells, and promotes B-cell differentiation. To test whether IL-21 participates in the pathogenesis of primary Sjögren's syndrome (SS), serum IL-21 level was measured and IL-21 expression in the labial salivary glands (LSG) was examined.

METHODS

Serum IL-21 levels in 40 primary SS, 40 rheumatoid arthritis (RA), and 38 systemic lupus erythematosus (SLE) patients and 20 healthy controls were measured. Serum IL-21 levels of SS patients were assessed for correlations with laboratory data, including anti-nuclear antibody, anti-Ro/La antibodies, globulin, immunoglobulin (Ig) class, and IgG subclass. LSGs from 16 primary SS and 4 controls with sicca symptoms were evaluated for IL-21 and IL-21 receptor (IL-21R) expression by immunohistochemistry. Confocal microscopy was performed to further characterize the IL-21 positive cells.

RESULTS

Primary SS patients had significantly higher serum IL-21 levels than controls, and these increments correlated positively with levels of IgG, IgG1. Serum IgG1 levels correlated with anti-Ro antibody titers. Immunohistochemical analyses showed that lymphocytic foci and the periductal area of the LSGs from SS patients expressed high levels of IL-21 and lower levels of IL-21R, whereas the control LSGs showed minimal expression of both antigens. The more the lymphocyte infiltrated, IL-21 expression in LSGs showed a tendency to increase. Confocal microscopic analyses revealed that IL-21 expressing infiltrating lymphocytes in the LSGs of SS patients also expressed CXCR5.

CONCLUSIONS

Primary SS is associated with high serum IL-21 levels that correlate positively with serum IgG, especially IgG1, levels. The expression of IL-21 is increased as more lymphocytes infiltrated in LSGs. These observations suggest that IL-21 may play an important role in primary SS pathogenesis.

The change of bone mineral density according to treatment agents in patients with ankylosing spondylitis

OBJECTIVES

The aim was to access the effects of treatment on bone mineral density (BMD) by treatment agents in patients with ankylosing spondylitis (AS).

METHODS

We analyzed clinical characteristics of 90 AS patients. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and x-ray of lumbar spine (L-spine) and sacroiliac joint were included in the baseline assessment. The BMDs of right femur and L-spine were measured annually using dual x-ray absorptiometry (DXA). The patients were divided into one of the following four groups by agents exposed for the follow-up period: conventional treatment, bisphosphonate, anti-TNF-α agent or bisphosphonate + anti-TNF-α agent. We evaluated the changes of BMD according to treatment groups.

RESULTS

The average age of disease onset was 30 years and the mean disease duration was 8.2 years. The patients who were assigned to the groups of conventional treatment, bisphosphonate, anti-TNF-α agents and bisphosphonate + anti-TNF-α agents were 40, 20, 19 and 11. BMDs values of both L-spine and femur showed tendencies to the most increase in the group treated with concurrent bisphosphonate and anti-TNF-α agent. However, the change of BMD by treatment agents was significant different only in trochanter (P = 0.001). In patients without syndesmophyte, there was significant difference of BMD change in both L-spine and total proximal femur (P = 0.001, 0.004). The BMD change of trochanter was correlated with the reductions of ESR and CRP (r = 0.239, P = 0.035 and r = 0.233, P = 0.040).

CONCLUSIONS

The BMDs of AS patients increased more by the treatment of concurrent bisphosphonate and anti-TNF-α agents. The gain of bone mass was associated with the reduction of inflammation.

The causes of death in Korean patients with systemic lupus erythematosus over 11 years

We investigated the causes of death and analyzed the prognostic factors in Korean systemic lupus erythematosus (SLE) patients. We evaluated 1010 patients with SLE who visited Seoul Saint Mary's Hospital from 1997-2007. Changing patterns in the causes of death were analyzed. Survival rate was calculated by the Kaplan-Meier method and the log-rank test. The risk factors for death were analyzed by multivariate logistic regression analysis. The 5-year survival rate was 97.8%. Over the period of the study, 59 deaths were observed. Among 44 patients who died in our hospital, the most common cause of death was infection (37.3%), with SLE-related death as the next most frequent cause (22.0%). In comparison with earlier data, the proportion of SLE-related deaths has fallen and the proportion of infections has risen. SLE-related death was the most frequent cause of early death, while infection was the most common cause of death in the overall population. In univariate analysis, damage related to SLE, cumulative glucocorticoid dose, mean glucocorticoid dose for 1 month before death, intravenous methylprednisolone therapy and cyclophosphamide treatment were associated with death (p < 0.001 each). The late onset of SLE and renal involvement were predictive factors of poor outcome (p = 0.03 and p < 0.001). In multivariate analysis, the risk factors for death were irreversible damage related to SLE, cyclophosphamide therapy and mean glucocorticoid dose for 1 month before death. The most common cause of death in Korean SLE patients was infection. The judicious use of immunosuppressive agents may be important to decrease infection and to improve survival in SLE patients.

Incidence of cancer among patients with systemic sclerosis in Korea: results from a single centre

OBJECTIVE

The aim of this study was to determine whether the incidence of cancer has increased among patients with systemic sclerosis (SSc) in Korea.

METHODS

The study subjects consisted of 112 patients who had been consecutively evaluated for at least 6 months between 1990 and 2007. We retrospectively reviewed their medical records, investigated the incidence rate of cancer and compared it with that of the Korea National Cancer Centre database.

RESULTS

Nine out of 112 patients developed cancer (four males and five females). The average age at diagnosis of cancer was 56.4 years and the mean disease duration was 8.9 years. The standardized incidence ratio (SIR) for SSc patients was 4.2 [95% confidence interval (CI) 2.3-6.1], 3.7 for women (95% CI 1.2-6.2) and 6.4 for men (95% CI 1.6-11.2). Lung cancer was the most common cancer (n = 4), followed by oesophagus (n = 1), stomach (n = 1), liver (n = 1), pancreas (n = 1), and squamous cell carcinoma of unknown origin (n = 1). All patients who developed lung cancer were female and non-small cell carcinoma in origin. The SIR of lung cancer in female patients was 23.0 (95% CI 6.0-40.0). Two out of four lung cancer patients had concomitant interstitial lung disease (ILD); all were non-smokers. Treatment agents, autoantibodies, smoking, and lung involvement were not significantly different between SSc patients with or without cancer.

CONCLUSION

The SIR of cancer was significantly higher in SSc patients, and especially in those who were male, than in the general population. Lung cancer was the most common cancer. Active surveillance for the detection of cancer should be performed in all SSc patients.

The silent progression of metastatic malignancy during the treatment with soluble tumor necrosis factor receptor

Etanercept is singular among anti-tumor necrosis factor alpha (TNF-alpha) agents, for being a soluble antibody to both TNF and lymphtoxin-alpha. The long-term neutralization of two cachexins by etanercept would theoretically compromise early detection of malignancy. This case reports a patient who was treated by etanercept for 21 months due to ankylosing spondylitis. Metastatic malignancy of unknown origin developed, and silently led the patient to lethal hepatic rupture. With an example of a malignancy masking effect of soluble TNF receptor, this article questions a need for vigilant attention to de novo carcinoma during the therapy, and calls for refined strategies in modulating autoimmune diseases.

Lupus mesenteric vasculitis can cause acute abdominal pain in patients with SLE

Lupus mesenteric vasculitis (LMV) is a unique clinical entity found in patients who present with gastrointestinal manifestations of systemic lupus erythematosus, and is the main cause of acute abdominal pain in these patients. LMV usually presents as acute abdominal pain with sudden onset, severe intensity and diffuse localization. Other causes of abdominal pain, such as acute gastroenteritis, peptic ulcers, acute pancreatitis, peritonitis, and other reasons for abdominal surgery should be ruled out. Prompt and accurate diagnosis of LMV is critical to ensure implementation of appropriate immunosuppressive therapy and avoidance of unnecessary surgical intervention. The pathology of LMV comprises immune-complex deposition and complement activation, with subsequent submucosal edema, leukocytoclastic vasculitis and thrombus formation; most of these changes are confined to small mesenteric vessels. Abdominal CT is the most useful tool for diagnosing LMV, which is characterized by the presence of target signs, comb signs, and other associated findings. The presence of autoantibodies against phospholipids and endothelial cells might provide information about the likelihood of recurrence of LMV. Immediate, high-dose, intravenous steroid therapy can lead to a favorable outcome and prevent serious complications such as bowel ischemia, necrosis and perforation.

Three-dimensional ultrasonographic application for analyzing synovial hypertrophy of the knee in patients with osteoarthritis

OBJECTIVE

The purpose of this study was to evaluate 3-dimensional (3D) ultrasonography for the visualization of intra-articular synovial hypertrophy in patients with osteoarthritis.

METHODS

Knee joints of 22 patients with osteoarthritis were examined by 3D ultrasonography, and their synovial fluids were analyzed. Ultrasonographic image patterns, vascular endothelial growth factor and transforming growth factor beta concentrations in synovial fluid, and serum inflammatory markers were analyzed.

RESULTS

It was possible to visualize the intra-articular structure by 3D ultrasonography. Three-dimensional ultrasonography revealed various interesting stereoscopic views of the synovial structures, and the patterns of synovial proliferation ranged from simple proliferations to complex shrubby structures. Patients with a more complex and proliferative pattern in the synovium tended to have higher C-reactive protein concentrations, but this difference was not significant (P = .09). The concentrations of vascular endothelial growth factor and transforming growth factor beta in synovial fluid were significantly higher in patients with complex hypertrophy (P < .05).

CONCLUSIONS

Three-dimensional technology was useful in delineating the shape of the synovium. It may have a possible impact on future imaging in rheumatology.

Visualization and localization of rheumatoid knee synovitis with FDG-PET/CT images

We annually evaluated (18)F-fluorodeoxyglucose-positron emission tomography/ computed tomography (FDG-PET/CT) scans for three consecutive years in a patient with rheumatoid arthritis. The inflammatory activity of the rheumatoid synovium was visualized in coronal and transverse sections by FDG-PET/CT. The extent and area of the synovial inflammation was relatively well delineated, and this technique was more informative in detecting inflammation than were conventional X-rays.

Application of three-dimensional computed tomography for the rheumatoid wrist

Recent technical advances in computed tomography (CT) and the introduction of three-dimensional (3D) image reconstruction through computer systems make distinct visualization of tiny defects in the hand and wrist a feasible task. Three wrists from three patients -- two of whom are patients with rheumatoid arthritis and one with osteoarthritis -- were evaluated by 3D CT. Images were obtained with a multidetector-row CT scanner. Bony wrist structures including erosions were observed in the patients with arthritis by means of 3D CT. 3D CT could clearly visualize bone-erosive lesions. It also revealed various interesting stereoscopic views of bony structures unattainable with conventional radiographic studies. 3D CT may serve to be interesting in future imaging studies in the rheumatology field.

Two-dimensional electrophoretic analysis of rice proteins by polyethylene glycol fractionation for protein arrays

Two-dimensional electrophoresis (2-DE) is known as the most effective as well as one of the simplest methods for separating proteins. However, a few hundred plant leaf proteins out of thousands visualized on a 2-DE gel can be identified by chemical analysis due to the presence of ribulose bisphosphate carboxylase/oxygenase (Rubisco) that limits protein loading. We describe the extraction and fractionation technique with polyethylene glycol (PEG) to analyze rice leaf proteins. Rice proteins were extracted with Mg/NP-40 extraction buffer. The Mg/Nonidet P-40 (NP-40) buffer extract was further fractionated with PEG into three fractions: 10% PEG and 10-20% PEG precipitants and the final supernatant fraction that was precipitated with acetone. Rubisco, the most abundant rice leaf protein, was enriched in the 20% PEG precipitant. This fractionation technique analyzed at least 2,600 well-separated protein spots and exhibited less than 1.2% of noticeable overlapping spots. An immunological approach was used to verify the efficiency whether PEG fractionation technique can detect or enrich signal transduction components such as Galpha, ADP ribosylation factor, small GTP binding protein and 14-3-3. The ADP ribosylation factor (ARF) and Galpha were only detected in the PEG supernatant fraction not in the total protein fraction. The small GTP binding protein (Rab 7) was identified in the 10% PEG fraction and only faintly in the total protein fraction. The 14-3-3 protein was detected in all fractions but was especially prevalent in the 20% PEG fraction.

Two-dimensional electrophoretic analysis of rice proteins by polyethylene glycol fractionation for protein arrays

Two-dimensional electrophoresis (2-DE) is known as the most effective as well as one of the simplest methods for separating proteins. However, a few hundred plant leaf proteins out of thousands visualized on a 2-DE gel can be identified by chemical analysis due to the presence of ribulose bisphosphate carboxylase/oxygenase (Rubisco) that limits protein loading. We describe the extraction and fractionation technique with polyethylene glycol (PEG) to analyze rice leaf proteins. Rice proteins were extracted with Mg/NP-40 extraction buffer. The Mg/Nonidet P-40 (NP-40) buffer extract was further fractionated with PEG into three fractions: 10% PEG and 10-20% PEG precipitants and the final supernatant fraction that was precipitated with acetone. Rubisco, the most abundant rice leaf protein, was enriched in the 20% PEG precipitant. This fractionation technique analyzed at least 2,600 well-separated protein spots and exhibited less than 1.2% of noticeable overlapping spots. An immunological approach was used to verify the efficiency whether PEG fractionation technique can detect or enrich signal transduction components such as Galpha, ADP ribosylation factor, small GTP binding protein and 14-3-3. The ADP ribosylation factor (ARF) and Galpha were only detected in the PEG supernatant fraction not in the total protein fraction. The small GTP binding protein (Rab 7) was identified in the 10% PEG fraction and only faintly in the total protein fraction. The 14-3-3 protein was detected in all fractions but was especially prevalent in the 20% PEG fraction.

Isolation of TC/AG repeat microsatellite sequences for fingerprinting rice blast fungus and their possible horizontal transfer to plant species

Genome fingerprinting has been a major role in characterization of population structure and analysis of the variability in phytopathogenic fungi. In order to characterize Korean rice blast fungal isolates, the genomic DNAs were digested with AluI endonuclease and subsequent PCR amplifications using random decamer primers with combinations of microsatellite primers had been carried out. This Alu-Inter SSR technique revealed high polymorphism among the Korean blast fungal isolates. Then, fragments from the Alu-Inter SSR analysis were isolated to be used as probes in Southern hybridization, which also revealed high polymorphism between isolates to distinguish individuals. The sequences of the isolated fragments contained TC/AG tandem repeats interspersed with a 30 bp direct repeat. In gel blot analysis, the isolated TC/AG repeat microsatellite sequences were proved to be useful for characterizing the isolates in blast fungi in addition to the conventional MGR (Magnaporthe grisea repeat) probes. One interesting point was that the rice blast fungus derived TC/AG repeat microsatellite sequences were abundant in non-rice blast fungi and plant species, but not in other fungi and yeasts. A discussion on the possible horizontal gene transfer between phytopathogenic fungi and host plants is presented.

Isolation and identification of antifungal N-butylbenzenesulphonamide produced by Pseudomonas sp. AB2

An antifungal bacterial strain, isolated from a greenhouse soil sample, inhibits growth of microflora nearby. It was selected for further studies of bacterial antifungal properties. This isolate was identified as a Pseudomonas sp. based on carbohydrate utilization, and other biochemical and physiological tests. Petri plate assay revealed that the Pseudomonas sp. exhibited antifungal activity against the plant pathogens, Pythium ultimum, Rhizoctonia solani, Phytophthora capsici, Botrytis cinerea and Fusarium oxysporum. Using direct inhibition bioassay on TLC plates after ethyl acetate extraction of the culture filtrate, we correlated antifungal activity with production of antifungal compounds. An antifungal antibiotic was isolated from the culture filtrate and was identified as N-butylbenzenesulphonamide. ED50, values of the N-butylbenzenesulphonamide against P. ultimum, P. capsici, R. solani, and B. cinerea were 73, 41, 33 and 102 ppm, respectively.

Epidermal grafts for treatment of stable and progressive vitiligo

BACKGROUND

Previous reports have shown the effectiveness of epidermal grafts for patients with stable vitiligo.

OBJECTIVE

Our purpose was to evaluate the effectiveness and complications of epidermal grafts in patients with stable and progressive vitiligo and to compare the results in both groups.

METHODS

Epidermal grafting with suction blisters was performed in 40 patients with vitiligo (26 stable and 14 progressive). The grafted sites and donor sites were examined for repigmentation for longer than 3 months, up to 2.5 years.

RESULTS

Complete repigmentation was observed in 19 patients with stable (73.1%) and 10 with progressive vitiligo (71.4%). Of the 29 patients who experienced complete repigmentation, we noted recurrences in 2 patients with stable disease (10.5%) and 4 with progressive disease (40%).

CONCLUSION

Although patients with progressive vitiligo showed more frequent recurrence than those with stable disease, epidermal grafting may be an effective treatment not only for stable vitiligo but also for progressive vitiligo.

A new class II rice chitinase, Rcht2, whose induction by fungal elicitor is abolished by protein phosphatase 1 and 2A inhibitor

Among the four classes of chitinase, a class II chitinase had not yet been reported for rice. We have isolated and characterized a class II acidic chitinase, Rcht2, from rice (Oryza sativa L. cv. Cheongcheongbyeo). The protein consists of a single polypeptide chain of 261 amino acid residues and includes a putative signal sequence of 29 amino acids at its N-terminus. It has a calculated molecular mass of 27,642 Da and an isoelectric point of 5.56. The Rcht2 chitinase lacks the cysteine-rich and hinge domains in the N-terminal region of the protein, which is the criterion for its classification as a class II chitinase. Comparison of the genomic and the cDNA sequence revealed that the coding region of Rcht2 consist of three exons of 301, 112, and 370 bp separated by two introns of 89 and 984 bp. In suspension-cultured rice cells, the transcript level of Rcht2 was dramatically increased by treatment with both glycol chitin and fungal elicitor. The application of protein phosphatase 1 and 2A inhibitors, calyculin A and okadaic acid, effectively abolished the induction of Rcht2 in response to fungal elicitor. In contrast, the activation of Rcht2 transcript was not inhibited by both cycloheximide and protein kinase inhibitors. These results demonstrate that protein dephosphorylation events play a crucial role in the elicitor-mediated induction of Rcht2 in rice cells, while de novo protein synthesis is not required for induction.

Asbestos and cancer in the Sennan District of Osaka

The cancer incidence among asbestos workers in the Sennan District and its surrounding of Osaka Prefecture, Japan, and the results of a mass survey in the above area since 1957 were evaluated from view points of epidemiology. During the period from 1953 to 1979, 107 patients with asbestosis were admitted to this Hospital. Twenty-six (24%) of them died of various carcinoma; 21 had lung cancer, 2 pleural mesothelioma and 3 had stomach cancer. Respiratory insufficiency due to pulmonary asbestosis was responsible for 41 deaths (38%). by a cohort survey of the 297 asbestos workers in the same district, 4 cases of lung cancer, and 3 cases of gastric cancer were detected and cases of cohort survey were followed up for 19 years. Fifty-seven (10%) of 556 cases of silicosis and 14 (11%) of 125 cases of pneumoconiosis other than silicosis or asbestosis were found to have lung cancer, but no mesothelioma. These results indicate that lung cancer and mesothelioma are associated more frequently with asbestosis than with non-asbestos pneumoconiosis (p less than 0.001 as tested by chi2-test). The standardized mortality ratio of lung and stomach cancer among the inhabitants of the Sennan District was calculated based on the statistics during the period of 10 years (1968-1977). the ratio of observed death to expected death of both cancers was smaller than 1.1, and there was no significant increase of death of lung and stomach cancer, although the risk of lung cancer tended to increase among male inhabitants. Discussions were made on the problems related to asbestos industry.

Significance of the quantification and demonstration of hyaluronic acid in tissue specimens for the diagnosis of pleural mesothelioma

Hyaluronic acid in pleural tissues from patients with mesothelioma, carcinoma, and asbestosis of the lung was quantified by using specific glycosaminoglycan-degrading enzymes. In all cases of pleural mesothelioma, the quantity of hyaluronic acid in mg/g of dry tissue was at least 0.10 mg, whereas carcinomatous pleural tissue and pleura in asbestosis contained 0.02 to 0.03 mg/g of dry tissue.

Effects of asbestos and beryllium on release of alveolar macrophage enzymes

Rabbit alveolar macrophages were exposed in culture medium to asbestos, beryllium sulfate, and beryllium oxide. The specific activities of the lysosomal hydrolases, acid phosphatase beta-N-acetylglucosaminidase and beta-glucuronidase plus the glycolytic enzyme, phosphohexose isomerase were determined in the medium, whole-cell homogenates, mitochondrial fractions, and supernatant. These hydrolases increased significantly in the medium but not in the mitochondrial fraction of cells exposed to dusts. Asbestos and beryllium sulfate were highly cytotoxic for alveolar macrophages in vitro and the data suggested that these agents were not associated with an increase in enzyme synthesis but rather a direct cytotoxic effect at the macrophage membrane level. For induction of enzyme release in vitro, a higher concentration of beryllium oxide was needed when compared with asbestos and beryllium sulfate. The cytotoxicity and enzyme release induced by these agents may represent an important nonspecific mechanism by which they induce inflammation and perhaps local proliferation of fibroblasts.

Effects of zirconium and aluminum salts on the alveolar macrophages

Alveolar macrophages from the rabbit were exposed in the culture medium to zirconium and aluminum salts. The specific activities of the lysosomal hydrolases, that is acid phosphatase, beta-N-acetylglucosaminidase and beta-glucuronidase, were measured in the medium, whole cell homogenate, mitochondrial fraction, and in the supernatant fraction. A highly significant increase of these hydrolases was observed in the mitochondrial fraction from cells exposed to zirconium and aluminum salts as compared with those from control cell cultures. However, release of these enzymes into the medium was not much. The phenomenon of macrophage phagocytosis was observed morphologically in the cell cultures exposed in vitro to these metal compounds.

Experimental studies of sensitization to beryllium, zirconium, and aluminum compounds in the rabbit

In a study designed to assess the potential sensitizing and granulomagenic capacities of selected metallic salts, rabbits were inoculated intradermally with zirconium aluminum glycinate (ZAG), sodium zirconium lactate (NZL), aluminum chlorhydrate (ACH), BeSO 4, and ovalbumin (OVA) by single and multiple injections. Animals immunized with BeSO4 and with OVA developed delayed skin reactivity as well as antigen-specific alveolar macrophage migration inhibition. Neither single nor multiple injections of ZAG or ACH resulted in clear-cut positive skin reactivity, macrophage migration inhibitory factor (MIF) production, or lymphocyte stimulation. Rabbits inoculated with multiple injections of NZL (500 microng) showed some marginally positive macrophage migration inhibition and skin reactivity. Histologically, ZAG and ACH were found to induce well-organized foreign-body granulomas after intradermal injection in both normal and inoculated rabbits. NZL and BeSO4 also induced skin granulomas, but these were less organized and distinct. Cell viability and ultrastructural studies indicated that BeSO4 was highly toxic for isolated alveolar macrophages in vitro at concentrations above 10 microng/ml, but NZL and ZAG did not exert such an effect at these dose levels. BeSO4 also depressed lymphocyte stimulation in sensitized animals which demonstrated delayed skin reactivity and macrophage migration inhibition.