Biomedical subjects

H Okada

Publications and source records attributed to H Okada.

At least 325 records · Page 18Linked to original sources

PubMed1998

Enhancement of anti-tumor activity of natural killer cells by BALL-1, a B cell lymphoma line.

The anti-tumor activity of human peripheral blood mononuclear cells (PBMC) against various tumor cell line cells (K562, Daudi, KMG-2, and KATOIII) was enhanced by coculture with irradiated BALL-1, but not with other irradiated B cell line cells (NALM-1, Namalwa, and Daudi). PBMC cocultured with BALL-1, however, failed to exhibit evident cytotoxicity against autologous concanavalin A-induced lymphoblasts. The enhancement of the anti-tumor activity seemed not to be correlated with EBNA and HLA-DR expression on B cell line cells. Monoclonal antibodies (mAbs) against interleukin (IL)-2, interferon-gamma, IL-12, IL-15, tumor necrosis factor-alpha and lymphotoxin showed little or no suppression of the anti-tumor activity of PBMC treated with irradiated BALL-1. Furthermore, the culture supernatants of BALL-1 failed to enhance the anti-tumor activity of PBMC, suggesting no involvement of soluble factors in the induction of the anti-tumor activity. The anti-tumor activity of PBMC treated with BALL-1 was synergistically enhanced by an additional IL-2 stimulation. Periodate-lysine-paraformaldehyde-fixed, but not ethanol- or acetone-fixed, BALL-1 could significantly enhance the anti-tumor activity. Furthermore, BALL-1-derived membrane fraction, but not that of Daudi, enhances the anti-tumor activity. It was thus suggested that some membrane glycoproteins on the cell surface of BALL-1 play a crucial role in the induction of the anti-tumor activity. By analysis using mAbs against human leukocytes, we found that depletion of CD11b, CD16, and CD56-positive cells resulted in decreased anti-tumor activity, suggesting that the main effector cells in the BALL-1-induced anti-tumor activity were natural killer (NK) cells. The present results thus raise the possibility that BALL-1, probably via membrane glycoproteins, modulates NK cell-mediated anti-tumor activity.

Antibodies, Monoclonal↗

PubMed1998

Comparative analysis of blood chemical values in primary ketosis and abomasal displacement in cows.

Blood chemical values, including ketone bodies, were measured in 25 cows with abomasal displacement (displacement group), 16 cows with primary ketosis (ketosis group), and nine normal controls to investigate the pathophysiology of abomasal displacement. Increases in aspartate aminotransferase, gamma-glutamyl transpeptidase, non-esterified fatty acid (NEFA), and ketone bodies (3-hydroxybutyric acid and acetoacetic acid) were observed in the displacement and ketosis groups. Total cholesterol increased significantly in the ketosis group but decreased in the displacement group. Glucose was significantly low and reversely correlated to ketone bodies in the ketosis group but was not low and was not correlated with ketone bodies in the displacement group. While NEFA was correlated to ketone bodies in the ketosis group, it was not in the displacement group. A correlation between the values of acetoacetic acid and 3-hydroxybutyric acid was seen in both the ketosis and displacement groups. The fact that blood chemical values in ketosis cows were clearly different from those in displacement cows suggest that the biochemical mechanism of ketogenesis is different between these two groups.

Abomasum↗

PubMed1998

Construction and voiding functions of three types of orthotopic neobladders using colonic segments: the Kobe University experience.

BACKGROUND: At Kobe University Hospital we have created orthotopic neobladders since 1988 by using several colonic segments. Various types of neobladders were compared and a detailed description of these procedures and the voiding function outcome is presented. METHODS: Thirty-two men with invasive bladder carcinoma or recurrent carcinoma in situ underwent a radical cystectomy followed by orthotopic neobladder replacement using a right colonic, ileocolic or sigmoid colonic segment. The functional capacity, percentage of residual urine volume, configuration of the neobladder, and location in the pelvis were evaluated 1 year after surgery. Voiding function was evaluated using a questionnaire which included questions on diurnal and nocturnal continence, and by uroflowmetric analysis. RESULTS: Operative time, blood loss, and functional neobladder capacity did not differ for the 3 types of neobladders. The configuration of the right colonic and ileocolic neobladders resembled the shape of a rugby ball. The configuration of the sigmoid neobladder was oval. The right colonic and ileocolic neobladders tended to be located along the right side wall of the pelvis. The sigmoid neobladder was located in the center of the pelvis. Daytime and nocturnal continence was not affected by either the type of neobladder or its configuration or position. Neobladders located in the center of the pelvis exhibited a better maximum flow rate than those located along the right wall of the pelvis. CONCLUSION: The technical difficulty in constructing the 3 types of neobladders was approximately the same. For better voiding a neobladder should be located in the center of the pelvis.

Aged↗

PubMed1998

Clinical evaluation of random biopsy of urinary bladder in patients with superficial bladder cancer.

BACKGROUND: Superficial bladder cancer has a tendency to recur in the urinary bladder. One reason for recurrence is the presence of concomitant carcinoma in situ (CIS) or dysplasia. However, the usefulness of random biopsy of the urinary bladder has been unclear. METHODS: Between September 1990 and March 1996, 83 patients with superficial bladder cancer underwent mucosal biopsy of 6 different sites in the urinary bladder with macroscopically normal findings (random biopsy). The relationship between a positive biopsy (CIS or dysplasia) and the tumor characteristics was examined. The disease-free survival of the patients according to the biopsy results was determined. RESULTS: The positive biopsy rate was 24.1% (CIS, 14.5%; dysplasia, 9.6%). The incidence of positive biopsy in patients with high-grade (G3), pT1 tumors, 3 or more and non-papillary wide-based tumors was significantly higher than that in patients with 1 or 2 tumors, low-grade (G1, G2), pTa tumors and papillary tumors (P < 0.05). In patients with a single papillary tumor, positive biopsy was found in 9.5%. The disease-free survival in patients with a positive biopsy did not differ from that in patients with a negative biopsy, because intravesical bacillus Calmette-Guérin was instilled in patients with a positive biopsy. CONCLUSION: Our results indicate that random biopsy is useful for detecting concomitant CIS or dysplasia and in the choice of drugs for intravesical instillation.

Adult↗

PubMed1998

Preliminary report of a modified continent appendix stoma in a sigmoid urinary reservoir pouch.

BACKGROUND: The application of an appendix stoma in a Mainz urinary reservoir pouch is an established procedure and assures good continence. We modified this method for use with a sigmoid pouch. METHODS: In each of 3 men with bladder carcinoma, an appendix with a blood supply was prepared and anastomosed to the detubularized sigmoid pouch with a 3-cm submucosal tunnel. RESULTS: In all 3 patients, this procedure was performed successfully, and the pouch was completely continent. Self-catheterization could be performed without difficulty by 2 patients, and with slight resistance in the remaining patient. The patients are satisfied with their quality of life. CONCLUSIONS: We conclude, based on our findings and these preliminary observations, that this procedure is a potentially good alternative for the placement of continent stoma in continent urinary reservoir surgery.

Aged↗

PubMed1998

Clinical study of renal cell carcinoma with brain metastasis.

BACKGROUND: The clinical outcome of patients with renal cell carcinoma with brain metastasis was analyzed. METHODS: Nine patients (median age, 60 years) with primary renal cell carcinoma and distant metastasis, including brain metastasis, were treated. The median time to the development of brain metastasis was 15 months after the initial visit. Patients with poor performance status or progressive disease were treated with interferon or conservative therapy alone. Patients with good performance status and other well-controlled metastatic foci were treated either with radiotherapy, or by tumorectomy of brain metastasis, or both. The median follow-up was 26 months after the initial visit. RESULTS: The 1-year, cause-specific survival rate was 17%. Of the 5 patients treated with alpha-interferon alone, all died of disease after the treatments, without improvement of performance status, 1 to 4 months after the diagnosis of brain metastasis. Two of 4 patients who underwent radiotherapy were treated with a combination of gamma-knife and tumorectomy of brain metastasis. They remained alive 10 and 22 months after diagnosis of brain metastasis. The 2 patients who underwent the combination treatment of gamma-knife and tumorectomy showed improvement of their performance status after these treatments for brain metastasis. CONCLUSION: Brain metastasis is an unfavorable prognostic factor in renal cell carcinoma. Although a larger number of patients would be necessary to demonstrate the definitive effects of gamma-knife treatment, our results suggest that the combination of gamma-knife and tumorectomy of brain metastases may be recommended for selected patients with good performance status and other well-controlled metastatic foci.

Aged↗

PubMed1998

Assessment of proliferating cell nuclear antigen expression and prognosis in patients with renal cell carcinoma with pulmonary metastases.

BACKGROUND: The presence of proliferating cell nuclear antigen (PCNA) has been suggested as a more important prognostic marker than either grade or mitotic index in the prognosis of patients with renal cell carcinoma. We assessed the immunoreactivity of PCNA in primary lesions and pulmonary metastases from patients with renal cell carcinoma and correlated the results with various histopathologic features and prognostic factors. METHODS: We studied the relationship between PCNA expression and clinical prognostic factors from resected primary lesions and pulmonary metastases from 10 patients and primary lesions from 32 patients with renal cell carcinoma without metastases. The cells were immunohistochemically stained with PCNA monoclonal antibody (PC-10) and 1000 nuclei were counted. The results were expressed as a ratio of stained to total cells (PCNA labeling index, LI %). RESULTS: The PCNA LI of pulmonary metastatic nuclei was significantly higher than the PCNA LI of renal lesions either from patients with (P < 0.05) or without (P < 0.01) metastases. Also, the mean PCNA LI of the pulmonary lesions in patients dying within 3 years of diagnosis was higher than the mean PCNA LI of patients surviving greater than 3 years. CONCLUSION: Our findings suggest that the PCNA LI, which was determined by immunohistochemical analysis, is an important marker reflecting the biologic behavior of renal cell carcinomas. The degree of PCNA expression in this study was of prognostic significance.

Aged↗

PubMed1998

Expression of receptors for basic fibroblast growth factor on human periodontal ligament cells.

Basic fibroblast growth factor (FGF-2; bFGF) is a major mitogen for connective tissue cells, and participates in the healing process. It has already been reported that FGF-2 could be applicable to enhance periodontal regeneration. In the present study, we examined FGF receptor (FGFR) expression on human periodontal ligament (PDL) cells. The binding of [125I]-labeled FGF-2 to human PDL cells was studied by radioreceptor assay. The binding of [125I]-FGF-2 to PDL cells reached a plateau after 2.5 h incubation at 4 degrees C and was inhibited by the addition of unlabeled FGF-2 and acidic FGF (FGF-1; aFGF), but not insulin-like growth factor-I, platelet-derived growth factor and transforming growth factor-beta 1. Scatchard analysis revealed the presence of approximately 1.0 x 10(5) FGF-2 binding sites per cell with an apparent Kd of 1.2 x 10(-10) M. Interestingly, the binding of [125I]-FGF-2 on PDL cells reached its maximum at d 6 of the culture and then gradually decreased. Scatchard analysis also demonstrated that the number of FGFRs on a PDL cell was altered during the course of the culture, while the affinity between FGF-2 and its receptor was not. The responsiveness of PDL cells to FGF-2, which was monitored by the inhibitory effect on alkaline phosphatase activity, was reduced in proportion to the decrease in the number of FGFRs on the PDL cells. The present study suggests that PDL cells alter the responsiveness to FGF-2 during the course of the culture by changing the density of its receptor, and that the density of FGFR expression might be a marker of the cytodifferentiation of PDL cells into mineralized tissue forming cells.

Alkaline Phosphatase↗

PubMed1998

Comparative study of efficacy of plasma exchange versus intravenous gammaglobulin treatment on acute postinfectious polyradiculoneuropathy: a preliminary report.

We tried to compare the efficacy of plasma exchange (PE) with that of intravenous immunoglobulin (IVIG) in patients with postinfectious polyneuritis (Guillain-Barré syndrome [GBS] and cranial neuritis). Fifteen patients with postinfectious polyneuritis were divided into 2 groups. The IVIG group included 5 cases of GBS and 2 cases of postinfectious cranial neuritis (ophthalmoplegic type). The PE group included 5 cases of GBS and 3 cases of postinfectious cranial neuritis (ophthalmoplegic type). The changes and incidences of improvement of muscle strength scores (MSSs) and ocular movement scores (OMSs) were evaluated before treatment and 1, 2, 3, and 4 weeks after treatment. No significant differences between the IVIG and PE groups were found in the MSSs or OMSs at any time after treatment. These data suggested that PE and IVIG had equivalent efficacy. In the IVIG group, the proportion of suppressor-inducer T cells significantly increased (p < 0.01) (before versus after treatment), and the proportion of suppressor-effector cells also increased but not significantly (before versus after treatment). In the PE group, the percentage of suppressor-inducer T cells significantly decreased (p < 0.05) (before versus after treatment) while the proportion of suppressor/cytotoxic T cells significantly increased (p < 0.05) (before versus after treatment). The percentage of suppressor-effector T cells also increased (before versus after treatment) but not significantly.

Acute Disease↗

PubMed1998

Elevated bradykinin and decreased carboxypeptidase R as a cause of hypotension during tryptophan column immunoabsorption therapy.

Tryptophan column immunoabsorption therapy is beneficial to the patient with a neuroimmunological disease, but some complications have been attributed to this treatment. There have been some instances of an abrupt shock state along with severe decreases in blood pressure. In regards to this shock state, it has been reported that plasma bradykinin levels increase during tryptophan column immunoabsorption therapy. In this study, we examined the correlation between plasma bradykinin levels and either blood pressure or the levels of its degrading enzymes, angiotensin converting enzyme (ACE) and carboxypeptidase R (CPR) in 6 patients. Increased concentrations of bradykinin were present in the latter half of the therapeutic interval, and plasma bradykinin levels were found to be inversely correlated to CPR activity. The decreased CPR level could augment the activities of bradykinin. We speculate that bradykinin could be responsible for the hypotension occurring in patients during tryptophan column immunoabsorption therapy and that the metabolism of bradykinin could be caused by the decreased activity of CPR.

Blood Pressure↗

PubMed1998

Molecular characterization and heterologous expression of the gene encoding a low-molecular-mass endoglucanase from Trichoderma reesei QM9414.

We have isolated the genomic and cDNA clones encoding EG III (a low-molecular-mass endo-beta-1,4-glucanase) gene from Trichoderma reesei QM9414. The nucleotide sequence of the cDNA fragment was verified to contain a 702-bp open reading frame that encodes a 234-amino-acid propeptide. The deduced protein sequence has significant homologies with family H endo-beta-1,4-glucanases. The 16-amino-acid N-terminal sequence was shown to function as a leader peptide for possible secretion. Northern blot analysis showed that the EG III gene transcript, with a length of about 700 bp, was expressed markedly by cellulose but not by glucose. The protein has been expressed as a mature form in Escherichia coli and as secreted forms in Saccharomyces cerevisiae and Schizosaccharomyces pombe under the control of tac, alcohol dehydrogenase (ADH1), and human cytomegalovirus promoters, respectively. The S. cerevisiae and Schizosaccharomyces pombe recombinant strains showed strong cellulolytic activities on agar plates containing carboxymethyl cellulose. The E. coli strain expressed small amounts of EG III in an active form and large amounts of EG III in an inactive form. The molecular masses of the recombinant EG IIIs were estimated to be 25, 28, and 29 kDa for E. coli, S. cerevisiae, and Schizosaccharomyces pombe, respectively, by immunoblot analysis following sodium dodecyl sulfate-polyacryl-amide gel electrophoresis. Parts of the yeast recombinant EG IIIs decreased their molecular masses to 25 kDa after treatment with endoglycosidase H and alpha-mannosidase, suggesting that they are N glycosylated at least partly.

Amino Acid Sequence↗

PubMed1998

Purification and Characterization of Exo-beta-d-Glucosaminidase from a Cellulolytic Fungus, Trichoderma reesei PC-3-7.

Chitosan-degrading activities induced by glucosamine (GlcN) or N-acetylglucosamine (GlcNAc) were found in a culture filtrate of Trichoderma reesei PC-3-7. One of the chitosan-degrading enzymes was purified to homogeneity by precipitation with ammonium sulfate followed by anion-exchange and hydrophobic-interaction chromatographies. The enzyme was monomeric, and its molecular mass was 93 kDa. The optimum pH and temperature of the enzyme were 4.0 and 50 degrees C, respectively. The activity was stable in the pH range 6.0 to 9.0 and at a temperature below 50 degrees C. Reaction product analysis from the viscosimetric assay and thin-layer chromatography and H nuclear magnetic resonance spectroscopy clearly indicated that the enzyme was an exo-type chitosanase, exo-beta-d-glucosaminidase, that releases GlcN from the nonreducing end of the chitosan chain. H nuclear magnetic resonance spectroscopy also showed that the exo-beta-d-glucosaminidase produced a beta-form of GlcN, demonstrating that the enzyme is a retaining glycanase. Time-dependent liberation of the reducing sugar from partially acetylated chitosan with exo-beta-d-glucosaminidase and the partially purified exo-beta-d-N-acetylglucosaminidase from T. reesei PC-3-7 suggested that the exo-beta-d-glucosaminidase cleaves the glycosidic link of either GlcN-beta(1-->4)-GlcN or GlcN-beta(1-->4)-GlcNAc.

Journal Article↗

PubMed1998

A novel approach for detecting an immunodominant antigen of Porphyromonas gingivalis in diagnosis of adult periodontitis.

In the course of long-term infection with Porphyromonas gingivalis in adult periodontitis, a specific antibody response to this organism is generated. We describe a potential novel approach for identifying an immunodominant antigen in human periodontitis patients. First, various monoclonal antibodies (MAbs) were established from mice immunized with crude antigen preparations of P. gingivalis FDC 381. The antigen specificities of these MAbs were compared with those of serum antibodies of 10 periodontitis patients in a competitive enzyme-linked immunosorbent assay. The binding of one MAb (termed PF18) was readily inhibited by sera from all patients but not by sera from healthy volunteers. The antigen recognized by PF18 existed on the cell surface, presumably in the capsule layer, shown by immunoelectron microscopic analysis. Purification of the antigenic substance, termed PF18-Ag, was performed by immunoaffinity chromatography with the MAb. Characterization of PF18-Ag suggested that the epitope was composed of carbohydrates but not peptides and that the substance was different from lipopolysaccharide. Measurement of levels of serum antibody to PF18-Ag better discriminated periodontitis patients from healthy individuals than measurement of antibodies to crude antigen preparations of P. gingivalis. Immunoglobulin G2 was the predominant isotype among the antibodies to PF18-Ag in the patients' sera. These results suggest that PF18-Ag, which is possibly a novel substance, is an important antigenic substance and is potentially useful for the clinical diagnosis of adult periodontitis. The approach that was used would also be relevant to detecting immunodominant antigens of other infectious microorganisms.

Adult↗

PubMed1998

Detection of anti-cytokeratin 8 antibody in the serum of patients with cryptogenic fibrosing alveolitis and pulmonary fibrosis associated with collagen vascular disorders.

BACKGROUND: It has been suggested that the humoral immune system plays a role in the pathogenesis of cryptogenic fibrosing alveolitis (CFA). Although circulating autoantibodies to lung protein(s) have been suggested, none of the lung proteins have been characterised. The purpose of this study was to determine the antigen to which the serum from patients with pulmonary fibrosis reacted. METHODS: The anti-A549 cell antibody was characterised in a patient with CFA using Western immunoblotting and immunohistochemical staining of A549 cells. As we identified that one of the antibodies against A549 cells was anti-cytokeratin 8, the expression of mRNA of cytokeratin 8 in A549 cells was evaluated. In addition, we attempted to establish an enzyme linked immunosorbent assay to measure the levels of anti-cytokeratin 8 antibody in the serum of patients with CFA and pulmonary fibrosis associated with collagen vascular disorders (PF-CVD). RESULTS: Initially two anti-A549 cell antibodies were detected in the serum of patients with pulmonary fibrosis, one of which was characterised as anticytokeratin 8 antibody by Western immunoblotting. We were able to establish an ELISA to measure anti-cytokeratin 8 antibody and found significantly higher levels in patients with CFA and PF-CVD than in normal volunteers, patients with sarcoidosis, pneumonia, and pulmonary emphysema. CONCLUSIONS: One of the anti-A549 cell antibodies in the serum of patients with CFA was against cytokeratin 8. The serum levels of anti-cytokeratin 8 antibody were increased in patients with CFA and PF-CVD. These results suggest that anticytokeratin 8 antibody may be involved in the process of lung injury in pulmonary fibrosis.

Adult↗

PubMed1998

Identification of a novel cis-acting element for fibroblast-specific transcription of the FSP1 gene.

The FSP1 gene encodes a filament-binding S100 protein with paired EF hands that is specifically expressed in fibroblasts. This led us to look for cis-acting elements in the FSP1 promoter that might engage nuclear transcription factors unique to fibroblasts. The first exon of FSP1 is noncoding, therefore, a series of luciferase reporter minigenes were created containing varying lengths of 5'-flanking sequence, the first intron, and the noncoding region of the second exon. A position and promoter-dependent proximal element between -187 and -88 bp was shown to be active in fibroblasts but not in epithelium. Sequence in the first intron from +777 to +964 had an enhancing effect that was not cell type specific. Hsv TK reporter constructs driven by this promoter/intron cassette in transgenic mice were coexpressed appropriately with FSP1 in tissue fibroblasts. Gel mobility shift competitor assays identified a novel domain, FTS-1 (fibroblast transcription site-1; TTGAT from -177 to -173 bp), that specifically interacts with nuclear extracts from fibroblasts. The necessity of this binding site was confirmed by site-specific mutagenesis. Database searches also turned up putative FTS-1 sites in the early promoter regions of other fibroblast expressed proteins, including the alpha1 and alpha2(I), and alpha1(III) collagens and the alphaSM-actin gene. We hypothesize that the selective engagement of FTS-1 elements may contribute to the mesenchymal phenotype of fibroblasts and perhaps other dedifferentiated cells.

3T3 Cells↗

PubMed1998

Protection of xeno-hepatocytes from complement-mediated cytolysis by transduction with homologous restriction factor 20 gene using retroviral vector.

Xeno-hepatocyte transplantation has the possibility to substitute for clinical liver transplantation in certain restricted hepatic diseases such as inherited metabolic disorders. To overcome human complement-dependent cytotoxicity on xeno-hepatocytes, the effectiveness of ex vivo transfer with the homologous restriction factor 20 (HRF20, CD59) gene was examined on primary-cultured xeno-hepatocytes using a retroviral vector. Primary-cultured rat hepatocytes transduced with HRF20 cDNA expressed HRF20 antigen by flow cytometric analysis and showed the integration of HRF20 cDNA to the genomic DNA by the polymerase chain reaction. The viability of rat hepatocytes incubated with 50% human serum was decreased due to complement-dependent cytotoxicity, whereas that of the transfectant was significantly protected (77.2+/-9.4 vs. 97.8+/-5.2%, p < 0.01). It was concluded that primary-cultured xeno-hepatocytes transduced with HRF20 cDNA using a retroviral vector could escape complement-dependent cytolysis by human serum.

Animals↗

PubMed1998

Biophysical signals underlying myogenic responses in rat interlobular artery.

-To assess cellular mechanisms mediating myogenic responses of interlobular artery (ILA), experiments were performed with the use of isolated perfused hydronephrotic kidneys. ILAs were divided into 3 groups according to their basal diameters: proximal (>60 microm), intermediate (40 to 60 microm), and distal (<40 microm) ILAs. Myogenic responses were obtained by stepwise increase in perfusion pressure. Greater myogenic responsiveness was observed in ILAs with smaller diameters. Diltiazem (10 micromol/L) inhibited myogenic responses of all segments of ILAs. Furthermore, gadolinium (10 micromol/L), a mechanosensitive cation channel blocker, abolished myogenic responses of distal but not proximal ILA. In contrast, 2-nitro-4-carboxyphenyl-N, N-diphenyl-carbamate (200 micromol/L), an inhibitor of phospholipase C, prevented myogenic responses of proximal but not distal ILA. Finally, basal proximal ILA diameters were increased by treatment with 50 nmol/L of staurosporine (P<0.05), and subsequent addition of thapsigargin (1 micromol/L) blocked myogenic contraction of proximal ILAs. Myogenic responses of intermediate ILAs exhibited characteristics between those of distal and proximal ILAs. Our data indicate that underlying mechanisms for myogenic responses differ in distinct segments of ILAs. The present results suggest that mechanosensitive cation channels are involved in myogenic constriction of distal ILAs. Finally, our findings provide evidence that the stimulation of phospholipase C mediates myogenic contraction of proximal ILAs.

Animals↗

PubMed1998

Cytokine expression in periodontal health and disease.

Soluble proteins that serve as mediators of cell function and are produced by various cell types, such as structural and inflammatory cells, are collectively called cytokines. Several lines of evidence have revealed that cytokines play important roles not only in tissue homeostasis but also in the pathogenesis of many infectious diseases. Recent research on biological activities in normal periodontium and the pathogenesis of periodontal diseases has clarified the involvement of various cytokines in the biological activities observed in the sites. Cytokines play crucial roles in the maintenance of tissue homeostasis, a process which requires a delicate balance between anabolic and catabolic activities. In particular, growth factors--such as fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), insulin-like growth factor (IGF), transforming growth factor-beta (TGF-beta)--are thought to play important roles in modulating the proliferation and/or migration of structural cells in the periodontium and the production of various extracellular matrices by these cells. On the other hand, there is little doubt that excessive and/or continuous production of cytokines in inflamed periodontal tissues is responsible for the progress of periodontitis and periodontal tissue destruction. Particularly, inflammatory cytokines--such as IL-1 alpha, IL-1 beta, IL-6, and IL-8--are present in the diseased periodontal tissues, and their unrestricted production seems to play a role in chronic leukocyte recruitment and tissue destruction. It is possible that monitoring cytokine production or its profile may allow us to diagnose an individual's periodontal disease status and/or susceptibility to the disease. In addition, although the hypothesis is still controversial, it has been suggested that discrete T-cell subsets (Th1 and Th2) with different cytokine profiles play specific roles in the immunopathogenesis of periodontal diseases.

Cell Division↗