Search PubMed⌕ Search

Biomedical subjects

Y Sakai

Publications and source records attributed to Y Sakai.

At least 91 records · Page 5Linked to original sources
PubMed2001

Porphyromonas gingivalis-specific IgG subclass antibody levels as immunological risk indicators of periodontal bone loss.

BACKGROUND: It has been well demonstrated a positive association between the magnitude of host antibody response and periodontal disease status. Previous studies also reported that Porphyromonas gingivalis-specific IgG subclass antibodies were elevated in sera from adult periodontitis patients. However, the rôle and the association of these IgG subclass antibodies to the development of periodontal diseases are poorly understood. AIM: The aim of present investigation was to examine the relation of serum IgG subclass antibody levels and alveolar bone loss in treated and untreated periodontitis patients. METHODS: Serum samples were taken from 20 treated and maintained periodontitis patients (SPT patients), 30 untreated patients and 19 periodontally healthy subjects. We determined the IgG subclass antibody titers to P. gingivalis whole cells using an enzyme-linked immunosorbent assay (ELISA). Subgingival plaque samples were taken from the mesio-buccal surface of 6 randomly selected teeth of SPT patients and evaluated for the presence of P. gingivalis by immunofluorescence microscopy. Clinical measurements were also taken including full mouth intraoral radiographs to measure interproximal alveolar bone loss at baseline (BLS1) and at a 5-year recall visit in the SPT patients (BLS2). RESULTS: Our results indicated that both patient groups had detectable levels of IgG1, IgG2, and IgG4. Significantly higher IgG1 was observed in both patient groups compared to the healthy subjects. The untreated patients also exhibited significantly elevated IgG2 response (p<0.05). The mean IgG4 level of the SPT patients was significantly higher compared to the other subject group (p<0.05). A statistically significant positive correlation between IgG2 levels and changes in bone levels (DeltaBLS: BLS2-BLS1) was seen in the SPT patients (p<0.001). SPT patients with high IgG2 and low IgG4 showed greater bone loss than those with low IgG2 and high IgG4 (p<0.05), although the mean prevalence of P. gingivalis in the 2 groups did not differ significantly. CONCLUSION: Our data suggest that the prolonged IgG2 response after periodontal treatment may be indicative of recurrent or persistent periodontal destruction.

Adult↗
PubMed2001

Enhanced anti-tumor effects of herpes simplex virus thymidine kinase/ganciclovir system by codelivering monocyte chemoattractant protein-1 in hepatocellular carcinoma.

The therapeutic efficacy of herpes simplex virus thymidine kinase/ganciclovir (HSV-tk/GCV) system in many types of tumors is unsatisfactory due to the insufficient spread of gene transfer and insufficient cell killing. In the current study, we investigated whether adenovirally delivered monocyte chemoattractant protein (MCP)-1 potentiates the antitumor effects of the HSV-tk/GCV system in hepatocellular carcinoma (HCC) cells. Subcutaneous tumor foci of the human HCC cell line, HuH7, established in athymic mice were directly transduced with a recombinant adenovirus (rAd) harboring an HSV-tk gene driven by a human alpha-fetoprotein promoter, followed by GCV administration. Subsequently, another rAd expressing MCP-1 under the universal CAG promoter was injected. The growth of tumors was markedly suppressed by codelivering HSV-tk and MCP-1 genes compared to that by either HSV-tk/GCV or MCP-1 delivery. In the tumor tissues, monocyte/macrophage infiltration was detected immunohistochemically. The antitumor effects of the rAd expressing MCP-1 were markedly reduced by the administration of carrageenan, a compound known to inactivate macrophage. These results indicate that adenovirally delivered MCP-1 enhanced the antitumor effects of the HSV-tk/GCV system synergistically by recruitment/activation of macrophages in tumor tissues, suggesting an effective immunotherapy for HCC and other lineages of tumors when used adjuvantly with a suicide gene.

Animals↗
PubMed2001

Skeletal muscle regeneration after insulin-like growth factor I gene transfer by recombinant Sendai virus vector.

We scrutinized the applicability and efficacy of Sendai virus (SeV) vectors expressing either LacZ or human insulin-like growth factor-I (hIGF-I) in gene transfer into skeletal muscle. Seven days after the intramuscular injection of LacZ/SeV X-gal labeled myofibers were demonstrated in rat anterior tibialis muscle with/without bupivacaine treatment and the transgene expression persisted up to 1 month after injection. Recombinant hIGF-I was detected as a major protein species in culture supernatants of a neonatal rat myoblast cell line L6 and thus induced the cells to undergo myogenetic differentiation. The introduction of hIGF-I/SeV into the muscle showed a significant increase in regenerating and split myofibers which were indicative of hypertrophy, and also an increase in the total number of myofibers, in comparison to that seen in the LacZ/SeV-treated control muscle. These results demonstrate that SeV achieves high-level transgene expression in skeletal muscle, and that hIGF-I gene transfer using SeV vector may therefore have great potential in the treatment of neuromuscular disorders.

Animals↗
PubMed2001

Radiation therapy in combination with transcatheter arterial chemoembolization for hepatocellular carcinoma with extensive portal vein involvement.

AIM: The aim of this study was to examine the effectiveness and toxicity of radiation therapy in combination with transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) with extensive portal vein tumor thrombus (PVTT). METHODS: The combined therapy was performed in 24 HCC patients with extensive PVTT. External radiation targeted for PVTT (50 Gy in 2 Gy fractions) was performed in combination with repetitive TACE for intralobar lesions using 30-60 mg epirubicin every 3 months, and associations of the following variables with the survival rate were evaluated: gender, age, viral etiology, Child's class, performance status, extrahepatic metastasis, size and number of HCC, and location of PVTT. RESULTS: The local response confined to PVTT was complete response (CR) in four patients, partial response (PR) in eight patients, no change (NC) in eight patients, and progressive disease (PD) in four patients. By using the stepwise Cox's regression analysis, only Child's class was associated with the survival rate. The survival rates after 1 and 2 years were 73 and 21% in Child's A, 10 and 0% in Child B or C, and 61 and 21% in patients in whom the local response was CR or PR, and 19 and 9% in those in whom the local response was NC or PD, respectively. By using the multiple logistic regression analysis, Child's class was the only factor associated with the local response (P = 0.006). CONCLUSIONS: The combined therapy is feasible and may be useful to reverse PVTT in patients with good hepatic function reserve.

Antineoplastic Agents↗
PubMed2001

Sleep-wake rhythm during stay in an intensive care unit: a week's long-term recording of skin potentials.

To monitor the sleep-wake cycle of patients during their stay in the intensive care unit (ICU), we tried continuous and long-term recording of skin potential (SP) levels in patients after surgery. A graph of the week-long SP showed the sleep-wake pattern to be evident until the fourth day. It disappeared beginning on the fifth day, resulting finally in delirium with a relatively high mean SP level. In another record, the administration of sedative agents to calm the excitement lowered the mean SP level and suppressed SP responses evoked by frequent day and night treatment or nursing care. Continuous monitoring of arousal level by SP will be of help in prevention of ICU syndrome.

Aged↗
PubMed2001

Need for sling surgery in patients with large cystoceles and masked stress urinary incontinence.

BACKGROUND: We studied the need for sling surgery in patients who suffered from large cystoceles and masked stress urinary incontinence. METHODS: Twenty patients who had large cystoceles but neither evidence nor history of stress incontinence were enrolled in this study. The cystocele was reduced using a reducing device. Masked urinary incontinence was identified by a 60 m pad weighing test and a stress test. The cystocele was reduced using a pessary ring in 14 patients, or a vaginal pack formed of two rolls of ordinary 28 x 28 cm gauze in six patients. Ten of 20 patients were diagnosed with masked stress urinary incontinence and were treated with anterior colporrhaphy and a suburethral sling procedure. The other 10 patients were continent after use of a cystocele reducing device and were treated with anterior colporrhaphy alone. Average follow-up periods of the patients with or without masked stress urinary incontinence were 51.2 months (range, 24.0-72.0 months) or 57.6 months (range, 27.0-70.0 months), respectively. RESULTS: One of the 10 patients diagnosed with masked stress incontinence had mild stress urinary incontinence postoperatively. None of the 10 continent patients had stress incontinence after anterior colporrhaphy alone. CONCLUSIONS: Reducing devices of protruding cystocele were clinically useful in the detection of masked stress incontinence. Sling surgery was effective to prevent emerging stress urinary incontinence for patients who suffered from cystocele and masked stress incontinence.

Aged↗
PubMed2001

Expression of cytokines after meniscal rasping to promote meniscal healing.

PURPOSE: We have developed a new surgical procedure of rasping a meniscal surface to repair a tear in the avascular zone. This procedure stimulates vascular induction to the tear, resulting in meniscal healing. The purpose of this study was to elucidate the mechanism of vascular induction and meniscal healing. TYPE OF STUDY: Randomized trial. METHODS: A full-thickness longitudinal tear of 5 mm in length was created in the avascular zone of the anterior segment of both medial menisci of rabbits. Meniscal rasping of about 0.5 mm in depth was then done on the femoral surface of the left meniscus from the parameniscal synovium to the inner portion including the longitudinal tear, and the right meniscus was left untreated as a control. After surgery, at 1, 7, 14, 28, 56, and 112 days, 4 rabbits were killed, both medial menisci were resected, and immunohistochemical staining with monoclonal antibodies was used to quantify expression of interleukin-1alpha (IL-1alpha), transforming growth factor-beta1 (TGF-beta1), platelet-derived growth factor (PDGF), and proliferating-cell nuclear antigen (PCNA) on the femoral surface of the menisci. A positive ratio of immunostaining was encountered. RESULTS: The positive ratio of IL-1alpha, TGF-beta1, PDGF, and PCNA on the rasped surface area reached its peak at 1, 7, 14, and 7 days, respectively, after surgery, and thereafter gradually declined. Although the time course of the positive ratio was different among these cytokines, the positive ratio on the rasped surface was significantly higher than that on the control surface at the early stage of the observation period. CONCLUSIONS: The cytokine network on the rasped meniscal surface appears to be the key to explaining the mechanism of vascular induction and meniscal healing by meniscal rasping.

Animals↗
PubMed2001

Microwave recanalization: thermal effects with nitinol and stainless-steel stents.

BACKGROUND AND STUDY AIMS: A previous study we conducted evaluated the thermal effects of microwave irradiation when attempting recanalization of a nitinol stent occluded by tumor ingrowth. The present study evaluates the thermal effects of microwave irradiation on different stents in vitro. METHODS: The thermal response to microwave energy was evaluated in a muscle-equivalent phantom containing a nitinol (Accuflex) or stainless-steel stent (Wallstent). The phantom temperature was monitored continuously at different distances from an electrode, with either stent type in place. The tip of the electrode was either in contact with the stent or not in contact with it. RESULTS: The steel stent showed a smaller temperature increase than nitinol at 2 mm from the electrode. Without electrode contact, the stents did not differ significantly during the first 40s of irradiation. The stents did not differ significantly with regard to temperatures further from the electrode. When the electrode was in contact with the stent, the rise in temperature was significantly greater with the stainless-steel stent than with the nitinol one, but the phantom temperature did not exceed 45 degrees C with either of the stents. CONCLUSIONS: In patients with a Wallstent stainless-steel stent, microwave coagulation therapy to recanalize stent occlusions appears to be feasible in the same conditions as with an Accuflex nitinol stent.

Alloys↗
PubMed2001

Transpapillary microwave coagulation therapy for recanalizing self-expandable metallic stents occluded by tumor ingrowth: initial experience.

Percutaneous microwave coagulation for recanalizing stents occluded by tumor ingrowth has been reported. With this technique, however, the percutaneous drain diminishes the quality of life in patients with unresectable tumors and a limited prognosis. Transpapillary microwave ablation was attempted in three patients with occluded stents. After a sheath had been inserted into the proximal hepatic duct across the occluded region, a microwave electrode was introduced into the intrahepatic duct via the sheath. We used microwave therapy with an output power of 40 W, based on our previous in vitro study. Except in one patient, the stents were successfully recanalized with one or two attempts. In one patient who underwent ablation in the intrahepatic duct, a 1.8-mm electrode enabled recanalization of the stent. In another who underwent ablation in the extrahepatic duct, however, a larger electrode was required. There were no procedure-related complications. Transpapillary microwave coagulation of occluded stents appears to be an alternative to percutaneous microwave coagulation with an electrode fitting the stent size. The technique might be easier with the use of a redesigned electrode with a guide wire lumen.

Aged↗
PubMed2001

Inhibitory effect of magnolol and honokiol from Magnolia obovata on human fibrosarcoma HT-1080. Invasiveness in vitro.

We investigated the inhibitory effect of Magnolia obovata Thunb. bark ethanol extracts on human fibrosarcoma HT-1080 cells invasion in a reconstituted basement membrane [Matrigel (MG)]. We found that the effective components of the bark ethanol extracts were magnolol and honokiol, two biphenyl compounds. The extracts, magnolol and honokiol, did not affect HT-1080 cells adhesion to MG, but did inhibit HT-1080 cells migration at a high concentration (100 microM). HT-1080 cells secrete matrix metalloproteinase (MMP)-9, which degrades the extracellular matrix as a part of the invasive process. Magnolol and honokiol inhibited the activity of MMP-9, which may have been responsible, in part, for the inhibition of tumor cell invasiveness.

Antineoplastic Agents, Phytogenic↗
PubMed2001

Knitted nitinol stent insertion for various intestinal stenoses with a modified delivery system.

BACKGROUND: Insertion of metallic stents for esophageal stenoses is well established, but these stents are technically difficult to place elsewhere in the GI tract. Moreover, major complications have occurred when metal stents with sharp ends have been placed in these locations. The currently available flexible, blunt-ended, knitted nitinol stent is intended for use only in the esophagus. Because its short delivery system cannot reach segments of the gut distal to the esophagus, the delivery device was modified to facilitate intestinal access, and its performance was evaluated in the treatment of malignant intestinal obstructions. METHODS: The Ultraflex delivery system was modified by connecting an additional plastic tube and a suture cord; the length was increased from 95 cm to 150 cm or more. Stents used were 18 to 23 mm in diameter, and 10 to 15 cm in length. A knitted metal stent was inserted by using the modified delivery system in 10 patients (7 men, 3 women, mean age 68 years); 8 with gastric outlet, 1 with jejunal, and 1 with proximal colonic obstruction. RESULTS: Metal stent insertion was successful in all patients with significant relief of symptoms and restoration of the ability to eat. The patient with a jejunal stent required placement of a second stent because of bending of the initial stent. No major complications (migration or perforation) occurred. CONCLUSION: This technique appears to facilitate placement of a metal stent with blunt ends in the duodenum, small intestine, and proximal colon. Manufacturers should offer blunt-ended stents with long delivery devices.

Aged↗
PubMed2001

Intracellular distribution of the antimutagenic enzyme MTH1 in the liver, kidney and testis of F344 rats and its modulation by cadmium.

Cellular distribution of the antimutagenic MTH1protein in the liver, kidney, and testis of Fischer rat was evaluated using the immunohistochemical staining with anti-MTH1 polyclonal antibody. The present investigation revealed a non-uniform distribution of MTH1 among cells and among the cytoplasmic, nuclear, and membranal structures of cells within a given tissue. A particularly strong expression of MTH1 was observed for the first time in the perinuclear acrosomic bodies of spermatocytes and in the acrosomic vesicles of sperm heads. Treatment of rats with a single sc dose of 20 micromol Cd(II)/kg body wt. produced histopathologic changes in these organs accompanied by redistribution of the cellular MTH1 protein between the cytoplasm and nuclei. The acute phase of Cd(II) toxicity, that in the liver and especially in the testes (but not in kidneys) led to cell necrosis, was accompanied by a characteristic decrease in the abundance of MTH1-expressing nuclei. Chronic toxicity without necrosis, persisting in the kidney over the entire 14-day study, as well as the survival and proliferation of cells, observed in the liver and testis after the necrotizing phase, were signified by increased number of nuclei expressing MTH1. Thus, unlike previous biochemical studies, immunohistochemistry managed to reveal alterations in the patterns of inter- and intracellular distribution of MTH1, associated apparently with the conditional changes in the dynamics of synthesis of nucleic acids, assisted by this protein.

Animals↗
PubMed2001

Difference in degree of mucosal atrophy between elevated and depressed types of gastric epithelial tumors.

BACKGROUND: The significance of atrophy in the background mucosa and Helicobacter pylori infection in the morphogenesis of gastric epithelial tumors has not yet been investigated. METHODS: The degree of mucosal atrophy, as determined by a histological analysis and the serum pepsinogen (PG) levels, and H. pylori status were investigated in patients with elevated adenoma (EA group; n = 40), elevated early cancer of intestinal type (ECI group; n = 30), depressed early cancer of intestinal type (DCI group; n = 37) and depressed early cancer of diffuse type (DCD group; n = 33), and the findings were then compared to those in 91 controls. RESULTS: At all sites of the stomach, the histologic score of atrophy was higher in the EA group and in the ECI group than in the controls. In the DCI group, the histologic score of atrophy in the antrum was higher than in the controls, but no such difference in the score was found in the DCD group. The PG I/II ratios in the EA, ECI and DCI groups were significantly lower than in the controls, and the value was also different between the ECI and DCI groups. While H. pylori prevalence was higher in all groups than in the controls, a logistic regression analysis which included the grade of atrophy as a determinant revealed the infection to be an independent associated factor for the DCD group. CONCLUSIONS: The difference in the background mucosal atrophy seems to contribute to different macroscopic types in gastric epithelial tumors. This seems to be the case especially for cancer of intestinal type.

Adenoma↗
PubMed2001

Unusual coronary artery aneurysm and acute myocardial infarction in a middle-aged man with systemic lupus erythematosus.

A 55-year-old man developed acute myocardial infarction (AMI) related to a large coronary artery aneurysm and a distal coronary stenotic lesion after steroid therapy for systemic lupus erythematosus (SLE). Only 13 SLE patients with AMI caused by coronary artery aneurysms have been reported, 11 of whom were young or middle-aged women and the 2 remaining were young men. This is the first report of a middle-aged man with multiple coronary lesions.

Arteriosclerosis↗