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Biomedical subjects

Isao Ishikawa

Publications and source records attributed to Isao Ishikawa.

At least 55 records · Page 3Linked to original sources
PubMed2004

Prevotella shahii sp. nov. and Prevotella salivae sp. nov., isolated from the human oral cavity.

Two bacterial strains, EHS11(T) and EPSA11(T), which were isolated from the human oral cavity, were characterized in terms of phenotypic and biochemical characteristics, cellular fatty acid profiles and phylogenetic position based on 16S rRNA gene sequence analysis. 16S rRNA gene sequence analysis showed that each of the isolates belonged to a novel species of the genus Prevotella. Strain EHS11(T) was related to Prevotella loescheii (about 95 % similarity), whereas strain EPSA11(T) was related to Prevotella oris (about 94 % similarity). Both strains were obligately anaerobic, non-pigmented, non-spore-forming, non-motile, Gram-negative rods. The cellular fatty acid composition of strain EPSA11(T) was very similar to that of P. oris JCM 8540(T). On the other hand, the cellular fatty acid composition of strain EHS11(T) was significantly different from those of other Prevotella species. The predominant fatty acids in strain EHS11(T) are C(18 : 1)omega9c, C(16 : 0) and C(16 : 0) 3-OH, whereas other Prevotella species, except for P. loescheii JCM 8530(T), possess anteiso-C(15 : 0), iso-C(17 : 0) 3-OH and C(18 : 1)omega9c. The predominant fatty acids in P. loescheii JCM 8530(T) are anteiso-C(15 : 0), C(16 : 0) and C(18 : 1)omega9c. DNA-DNA hybridization experiments revealed a genomic distinction of strains EHS11(T) and EPSA11(T) from P. loescheii JCM 8530(T) and P. oris JCM 8540(T). On the basis of these data, two novel Prevotella species are proposed: Prevotella shahii sp. nov. and Prevotella salivae sp. nov. The type strains of P. shahii and P. salivae are EHS11(T) (=JCM 12083(T)=DSM 15611(T)) and EPSA11(T) (=JCM 12084(T)=DSM 15606(T)), respectively.

DNA, Bacterial↗
PubMed2004

Changes in oral microbial profiles after periodontal treatment as determined by molecular analysis of 16S rRNA genes.

Terminal RFLP (T-RFLP) analysis was used to investigate changes in the oral microbiota in saliva and subgingival plaque samples from one patient with aggressive periodontitis (subject A) and two patients with chronic periodontitis (subjects B and C) before and 3 months after periodontal treatment. Substantial changes in the T-RFLP patterns of subgingival plaque samples of subjects B and C were noted after 3 months of improved oral hygiene and full-mouth supra- and subgingival scaling and root planing. However, there was little change in the subgingival microbiota of subject A. Although the proportions of terminal restriction fragments (T-RFs) larger than 1000 bp were notable in the T-RFLP patterns generated after digestion with HhaI of the samples from two subjects before treatment (subject B, 35.5 %; subject C, 29.6 %), the proportions of these T-RFs were significantly reduced or not detected after treatment (subject B, none; subject C, 4.1 %). Real-time PCR showed a significant change in the proportions of target bacteria in subgingival plaque samples of subject B. After 3 months, the Porphyromonas gingivalis population was markedly reduced (3.1 x 10(-3) %), whereas the proportion of Porphyromonas gingivalis before treatment was 7.6 %. The proportions of Tannerella forsythensis, Treponema denticola and Treponema socranskii were also markedly diminished after treatment. Similarly, the proportion of the T-RF presumed to represent Porphyromonas gingivalis was 5.9 % and became undetectable after 3 months. Analysis of 16S rRNA gene clone libraries from subgingival plaque samples of subject B before and after treatment showed a notable change in the subgingival microbiota. These results were in agreement with the T-RFLP analysis data and showed that the T-RFs larger than 1000 bp represent Peptostreptococcus species. Our results indicate that T-RFLP analysis is useful for evaluation of the effects of medical treatment of periodontitis.

Adult↗
PubMed2004

Effect of low dose Actinobacillus actinomycetemcomitans lipopolysaccharide pretreatment on cytokine production by human whole blood.

BACKGROUND AND OBJECTIVE: Periodontal disease is known to influence the systemic condition in various ways, and the bacteria and their products, such as lipopolysaccharides (LPS), may spread from periodontal lesions via the systemic circulation to affect distant organs. The level of LPS in plasma from such patients is reported to be very low, and this low level of LPS is suspected to have priming or desensitizing effect. Thus, we investigated the effects of low dose LPS pretreatment on LPS-dependent cytokine production by whole blood cells ex vivo. METHODS: Blood samples obtained from seven systemically and periodontally healthy individuals were pretreated with or without 5 pg/ml Actinobacillus actinomycetemcomitans LPS, followed by further stimulation with 1 ng/ml A. actinomycetemcomitans LPS. The concentrations of interleukin-1 beta (IL-1beta), IL-6, IL-10 and tumor necrosis factor-alpha (TNF-alpha) in the culture supernatants were then determined using enzyme-linked immunosorbent assay (ELISA). In addition, intracytoplasmic cytokine staining of whole blood cells was performed for flow cytometry. RESULTS: Pretreatment with 5 pg/ml A. actinomycetemcomitans LPS significantly enhanced the production of IL-1beta and IL-6 from whole blood when further induced by 1 ng/ml LPS (1.72 times higher for IL-1beta, 2.18 times higher for IL-6 than without pretreatment). The pretreatment did not enhance the production of either TNF-alpha or IL-10. Intracytoplasmic staining showed that the monocyte fraction was primarily involved in producing IL-1beta and IL-6. Flow cytometric analysis revealed that pretreatment increased the number of IL-1beta and IL-6 producing cells as well as mean fluorescence intensity of the stained cells. CONCLUSION: A low dose of bloodstream LPS found in periodontitis patients appears to be sufficient to prime monocytes, and may be capable of affecting the systemic responses of immune and inflammatory cells.

Adjuvants, Immunologic↗
PubMed2004

Potential applications of Erbium:YAG laser in periodontics.

OBJECTIVES: Since lasers were introduced for the treatment of oral diseases, there has been considerable advancement in technology. As a result, numerous laser systems are currently available for oral use. Neodymium:Yttrium-Aluminum:Garnet (Nd:YAG), carbon dioxide (CO(2)) laser and the semiconductor Diode lasers have already been approved by the US Food and Drug Administration for soft tissue treatment in oral cavity. The Erbium:YAG (Er:YAG) laser was approved in 1997 for hard tissue treatment in dentistry and recent studies have reported positive results. This suggests that the Er:YAG laser system is a promising apparatus, which will be able to revolutionize and improve dental practice, in particular periodontal treatment. In this mini-review, we would like to describe the positive characteristics of the Er:YAG laser which indicate its potential as a new treatment modality in periodontics. MATERIALS AND METHODS: Recent findings are summarized briefly to evaluate the potential of the Er:YAG laser for clinical application in periodontics. RESULTS: The Er:YAG laser possesses suitable characteristics for oral soft and hard tissue ablation. Recently, it has been applied for effective elimination of granulation tissue, gingival melanin pigmentation and gingival discoloration. Contouring and cutting of bone with minimal damage and even or faster healing can also be performed with this laser. In addition, irradiation with the Er:YAG laser has a bactericidal effect with reduction of lipopolysaccharide, high ability of plaque and calculus removal, with the effect limited to a very thin layer of the surface and is effective for implant maintenance. CONCLUSION: The Er:YAG laser seems to be an effective tool for periodontal therapy, however, further clinical and basic investigations are required to confirm its clinical application.

Aluminum Silicates↗
PubMed2004

The distribution of periodontopathic bacteria among Japanese children and their parents.

OBJECTIVE AND BACKGROUND: It is not well known how periodontopathic bacteria colonize in the oral cavity during childhood. The purpose of this study was to investigate the distribution of periodontopathic bacteria in oral cavities of children and their parents and the relationship between the bacterial findings and clinical parameters. METHODS: Fifty-six children (mean age: 8.3 +/- 3.5, range: 1-15 years), including 15 with deciduous dentition, 26 with mixed dentition and 15 with permanent dentition, and their parents participated in this study. Whole saliva and dental plaque of the children and whole saliva of their parents were collected for detection of seven species of periodontopathic bacteria (Actinobacillus actinomycetemcomitans, Tannerella forsythensis (Bacteroides forsythus), Campylobacter rectus, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens and Treponema denticola) using the polymerase chain reaction method. Clinical parameters including simplified Oral Hygiene Index and Papillary-Marginal-Attachment Index were recorded for the children and their accompanied parents. RESULTS: The detection frequencies of T. forsythensis, C. rectus, P. nigrescens, T. denticola, A. actinomycetemcomitans and P. gingivalis in the oral cavities of children were 42.9%, 94.6%, 42.9%, 48.2%, 1.8% and 8.9%, respectively. T. forsythensis, P. gingivalis and T. denticola were detected more frequently in the saliva of parents (54.8%, 54.8%, 88.1%, respectively) than in the saliva of children (25.5%, 7.3%, 41.8%, respectively). Different detection frequencies of P. nigrescens were found among the oral cavities of children with deciduous, mixed and permanent dentitions. In mixed dentition, females harbored T. forsythensis more frequently than males did. Children who harbored T. forsythensis, P. intermedia, P. nigrescens and T. denticola showed high scores for oral debris measurement by simplified Oral Hygiene Index. T. forsythensis, P. intermedia and P. nigrescens were detected more frequently in children whose parents were positive for these pathogens than in children whose parents were negative. CONCLUSIONS: High plaque retention seems to promote the colonization of periodontal pathogens in the oral cavities of children. T. forsythensis, P. intermedia and P. nigrescens were detected more frequently in the oral cavities of children whose parents already harbored these bacteria. Familial transmission of these bacteria is suggested.

Adolescent↗
PubMed2004

Renal cell carcinoma detected by screening shows better patient survival than that detected following symptoms in dialysis patients.

There is an apparent advantage to early or incidental diagnosis of renal cell carcinoma in the general population. We investigated whether the prognosis of dialysis patients with renal cell carcinoma is better if renal cell carcinoma is detected by screening of patients without symptoms rather than by examination after the appearance of the symptoms. Two groups in which renal cell carcinomas were detected by screening (N = 721) and by symptoms (n = 76) were compared. The model tested consisted of patient age and duration of dialysis in addition to the detection by screening or symptoms. Cox proportional hazard model was used to compare survival rates between the groups. The hazard ratio of death from all causes in patients with renal cell carcinoma detection by screening was 0.653 and the risk of death was reduced by 35%, compared with that in the group with detection due to symptoms. Moreover, the 50% survival rate in the group detected by symptoms was 80 months and the ratio of those detected by screening was 119 months. Therefore, screening provided a survival benefit of 39 months (3.3 years) in death from all causes after adjustment for age and duration of dialysis. The survival rate was best in young patients with a short duration of dialysis and renal cell carcinoma detected by screening. In dialysis patients with renal cell carcinoma, the survival rate in the group detected by screening was better than that in the group detected by symptoms. Especially, there was a large effect of screening for renal cell carcinoma in the young dialysis patients.

Adult↗
PubMed2004

Present status of renal cell carcinoma in dialysis patients in Japan: questionnaire study in 2002.

AIMS: To determine the incidence and recent trends of renal cell carcinoma (RCC) in dialysis patients, a nationwide investigation was performed in Japan. METHODS: In February 2002, 3,155 questionnaires were sent to dialysis units in Japan. The variables studied for RCC diagnosed between March 2000 and February 2002 included patient age, duration of dialysis, diagnostic aids, cancer size, histology of cancer, and the presence of metastasis and acquired cysts. RESULTS: 489 RCCs (381 males, 104 females, and 4 unknown) were studied. The mean age of the RCC patients was 57.5 +/- 11.4 (mean +/- SD) years, and the mean duration of dialysis was 136.9 +/- 95.2 months. RCC was detected by symptoms alone in 5.3% of the cases, by sonographic screening in 46.1%, and computed tomographic screening in 44.2%. The metastasis rate was 15.2%. The standardized incidence ratio was 9.7 (95% confidence interval, CI: 8.3-11.2) for the male dialysis patients and 11.0 (95% CI: 8.2-14.4) for the female patients. Eighty-four of the RCC patients with more than 20 years of hemodialysis were younger, were more frequently male, and demonstrated a larger cancer size, a higher incidence of papillary RCC, a higher metastasis rate, and a higher incidence of fatal RCC than 215 patients with less than 10 years of dialysis. CONCLUSION: 54.6% of the patients with RCC received dialysis for more than 10 years. For RCC patients with more than 20 years of dialysis, the mean age was younger, and the metastasis rate was higher than for RCC patients with less than 10 years of dialysis.

Adenocarcinoma, Clear Cell↗
PubMed2004

Role of ascorbic acid in periodontal ligament cell differentiation.

BACKGROUND: Periodontal ligament (PDL) cells form mineralized nodules in vitro. Ascorbic acid is known to be required in this process, although its effect on osteoblastic differentiation of PDL cells remains unclear. The purpose of this study was to determine the role of ascorbic acid on the early osteoblastic differentiation of PDL cells, with regard to alkaline phosphatase (ALP) activity, type I collagen production and integrin expression. METHODS: Cultured PDL cells were stimulated at confluence with ascorbic acid in the presence or absence of type I collagen inhibitor and blocking antibodies to integrins. After stimulation, the cells and culture supernatants were examined for ALP activity, type I collagen production, and integrin expression. The ALP activity was measured using a colorimetric assay with p-nitrophenyl phosphate and ALP staining. Enzyme-linked immunosorbent assay (ELISA) was used to determine type I collagen production, and ELISA and flow cytometric analysis were employed for assessment of integrin expression. RESULTS: Both ALP activity and type I collagen production were upregulated when PDL cells were cultured in the presence of ascorbic acid (200 microM). Inhibitor of the formation of collagen triple helices and blocking antibodies to alpha2beta1 integrin inhibited ALP activity by 50% in ascorbic acid-stimulated PDL cells. Furthermore, ascorbic acid increased the cell surface expression of alpha2beta1 integrin. CONCLUSIONS: Our findings indicated that ascorbic acid increases the ALP activity of PDL cells via type I collagen production and also enhances the expression of alpha2beta1 integrin, which is a major receptor of type I collagen. These results suggest that ascorbic acid promotes the osteoblastic differentiation of PDL cells by modulating type I collagen-alpha2beta1 integrin interaction.

Alkaline Phosphatase↗
PubMed2004

The mutant (F310L and V365I) tissue-nonspecific alkaline phosphatase gene from hypophosphatasia.

Hypophosphatasia (HOPS) is a heritable disorder characterized by defective skeletal mineralization, deficiency of tissue-nonspecific alkaline phosphatase (TNSALP) activity and premature loss of deciduous teeth. In a previous study, we detected missense mutations in the TNSALP gene of a patient who inherited the F310L and the V365I mutation with severe periodontitis and childhood HOPS. Expression of the mutant V365I TNSALP gene using COS-1 cells demonstrated that the protein translated from the mutant had undetectable ALP activity. In the present study, we characterized another ALP enzyme translated from the mutant F310L and compared it with the ALP in the patient's serum. The COS-1 cells transfected with the F310L and co-transfected with F310L and V365I (F310L/V365I) exhibited levels of 67% and 31%, respectively, with the enzymatic activity of the wild-type taken as 100%. In the thermostability test, TNSALPs in the COS-1 cells transfected with the mutant F310L or F310L/V365I were significantly more heat labile compared with that of the wild-type. Moreover, ALP from the patient's serum was also more heat labile than normal ALP. These results suggest that the protein translated from the mutant F310L, in addition to the mutant V365I, may be responsible for the expression of symptoms of the childhood-type HOPS.

Adult↗
PubMed2004

[Osteoporosis from the point of view of dental practice].

When dentists examine a patient with osteoporosis, they should consider the condition of periodontal disease, because both osteoporosis and periodontal disease share the same symptoms such as reduction of the bone volume. Many studies have attempted to define the relationship between these two diseases. Although most studies support a positive association between them, the mechanism of correlation still remains unclear. To establish novel treatment modalities of these diseases, further studies are necessary to elucidate the detailed mechanisms of interaction between them.

Female↗
PubMed2003

Cystic renal cell carcinoma, suspected because of lack of regression of renal cysts after renal transplantation in a dialysis patient with acquired renal cystic disease.

A 34-year-old man who had been on dialysis for about 6 years, and had acquired renal cystic disease, received a renal transplantation. However, in spite of the success of the transplantation, one area without cyst regression was observed in the original kidney. Therefore, carcinoma was suspected and nephrectomy was performed. Histology revealed cystic renal cell carcinoma (RCC). No case of cystic RCC occurring in a dialysis patient has previously been reported. Cystic RCC should be suspected in a cystic mass in the original kidney which does not regress after successful renal transplantation.

Adult↗