Biomedical subjects

H Kato

Publications and source records attributed to H Kato.

At least 361 records · Page 20Linked to original sources

PubMed2000

Effect of etching and sandblasting on bond strength to sintered porcelain of unfilled resin.

This study determined the bond strength of an unfilled resin joined to a feldspathic porcelain for the purpose of evaluating the retentive performance of the prepared material surfaces. Porcelain disks (VMK 68 dentin) were either air abraded with alumina (AAA) or etched with one of the following five etchants: (1) ammonium hydrogen bifluoride (AHB); (2) acidulated phosphate fluoride (APF); (3) hydrofluoric acid (HFA); (4) phosphoric acid (PHA); and (5) sulfuric acid-hydrofluoric acid (SHF). Specimens ground with abrasive paper were also used as controls. After surface preparation, the two different sized porcelain disks were bonded together with a methyl methacrylate-based resin initiated with tri-n-butylborane (MMA-TBB resin). Shear bond strengths were determined both before and after thermocycling. Before the thermocycling, the greatest bond strengths (21.3 and 23.7 MPa) were generated with the use of the SHF and HFA agents, followed by the AHB agent (18.4 MPa). Reduction in bond strength after thermocycling was significant for all groups, although the SHF- and HFA-treated groups exhibited bond strengths greater than 15 MPa even after the thermocycling. The results indicated the effectiveness of the SHF- or HFA-etching for retaining the acrylic resin to the porcelain. However, ageing testing also revealed insufficient retentive characteristics of the acrylic resin by etching alone.

Acid Etching, Dental↗

PubMed2000

Sepsis in children.

BACKGROUND: Sepsis remains lethal to children. At our institution, we have noted that approximately 2% of all hospitalized patients have had sepsis. In the present study, we analyzed episodes of sepsis that occurred in our ward. METHODS: Sepsis that occurred in our institution between January 1984 and December 1998 was reviewed and analyzed. RESULTS: Three hundred and sixty-six episodes of sepsis in 244 admitted patients were analyzed. Sepsis occurred in approximately 2% of all hospitalized patients. Forty-three of 244 patients were under 1 year of age. Eighty-seven percent (212/244) of cases had underlying diseases. Hematologic disorders or neoplasms were the most common underlying disease, comprising 55% of all patients (133/244). Two-hundred and fifty-one of 366 episodes of sepsis were acquired during hospitalization. We identified 409 causative agents. There were 25 polymicrobial infections (25/366; 7%). Gram-positive bacteria comprised 68% of all organisms (280/409). Staphylococcus aureus was the most common organism, comprising 18% of causing agents (75/409). Sixty-six organisms came from the insertion of a central venous catheter. Eighty-one patients experienced recurrent episodes of sepsis. In terms of complications, respiratory distress was the most common complication (36 episodes) and there were 15 episodes of shock. Thirty-seven patients died of sepsis. Sepsis caused by Gram-negative bacteria showed significantly higher mortality than Gram-positive bacteria (11/43 (26%) vs 15/146 (10%); P= 0.053). CONCLUSIONS: In our institution, approximately 20% of septic patients were under 1 year of age and 90% had underlying diseases. The causative agents of sepsis affected the outcome.

Adolescent↗

PubMed2000

Endocrine cell distribution and expression of tissue-associated antigens in human female paraurethral duct: possible clue to the origin of urethral diverticular cancer.

BACKGROUND: To investigate (i) what determines the histologic differences seen among female urethral diverticular cancers and (ii) the possible embryologic origin of the female paraurethral duct, we performed a distribution analysis of endocrine cells and a comparative study of tissue-associated antigens in the female paraurethral duct. METHODS: Six human female urethras were obtained from surgical and autopsy cases including two cases of urethral diverticular cancer (columnar/mucinous type adenocarcinoma). The urethral and paraurethral epithelia were examined histologically and immunohistochemically. RESULTS: Immunoreactive endocrine cells predominated and carcinoembryonic antigen (CEA) was strongly expressed in the larger portion of the paraurethral duct close to the urethral lumen. Conversely, prostate-specific antigen and prostatic acid phosphatase were positive only in the smaller distal duct. In two cases of adenocarcinoma including endocrine cells, cancer cells were strongly positive for CEA. CONCLUSIONS: This study suggests that the proximal and distal parts of the paraurethral duct have different histologic characteristics and that the pathologic differences seen among female diverticular cancers may result from their cancer-genesis from different parts of the paraurethral duct.

Adenocarcinoma, Mucinous↗

PubMed2000

Optimization of orthotopic colonic bladder: implantation of tubularized mucosal flap from colonic segment into demucosalized urethra.

If the urethral mucosa of a female could be replaced by another mucosa, one could augment the indication for orthotopic reconstruction of the bladder. A mucosal replacement technique for the female urethra is reported. A colonic mucosal flap formed from a colonic bladder was used in a patient with bladder cancer for whom cystectomy was indicated. For 3 years after the surgery, the patient has maintained satisfactory voiding and urethral function. There has been no evidence of a recurrence. The orthotopic bladder with the mucosal replacement technique can be applied to female patients who have a bladder cancer with a high risk of urethral recurrence.

Adult↗

PubMed2000

Development of gastric emptying in the human fetus.

OBJECTIVE: To evaluate stomach size and the development of gastric emptying in human fetuses using ultrasound. DESIGN: Clinical observational study. METHODS: The motility and peristalsis of the fetal stomach were studied in 80 normal fetuses between 12 and 39 weeks of gestation. Fetal gastric motility was assessed by analysis of videotaped recordings of ultrasound images of the stomach taken in real time. RESULTS: Fetal maximum gastric area gradually increased and minimum gastric areas gradually decreased after 20 weeks of gestation. At term, the maximum and minimum gastric area ratios were approximately 13 and 5%, respectively. The change in fetal gastric area, defined as the difference of maximum and minimum gastric area ratios, was relatively constant at 3% from 12 to 15 weeks of gestation to 20-23 weeks of gestation. It increased significantly (to 8%) after 24-27 weeks of gestation until term. CONCLUSIONS: Fetal gastric emptying was quantified and its development assessed during pregnancy. A critical point of gastric development, associated with an increase in the change of gastric volume, was identified at 24-25 weeks of gestation.

Fetus↗

PubMed2000

Mutant loricrin is not crosslinked into the cornified cell envelope but is translocated into the nucleus in loricrin keratoderma.

Loricrin is a major constituent of the epidermal cornified cell envelope. We have recently identified heterozygous loricrin gene mutations in two dominantly inherited skin diseases, the ichthyotic variant of Vohwinkel syndrome and progressive symmetric erythrokeratoderma, collectively termed loricrin keratoderma. In order to see whether the mutant loricrin molecules predicted by DNA sequencing are expressed in vivo and to define their pathologic effects, we raised antibodies against synthetic peptides corresponding to the mutated sequences of loricrin. Immunoblotting of horny cell extracts from loricrin keratoderma patients showed specific bands for mutant loricrin. Immunohistochemistry of loricrin keratoderma skin biopsies showed positive immunoreactivity to the mutant loricrin antibodies in the nuclei of differentiated epidermal keratinocytes. The immunostaining was localized to the nucleoli of the lower granular cell layer. As keratinocyte differentiation progressed the immunoreactivity moved gradually into the nucleoplasm leaving nucleoli mostly nonimmunoreactive. No substantial staining was observed along the cornified cell envelope. This study confirmed that mutant loricrin was expressed in the loricrin keratoderma skin. Mutant loricrin, as a dominant negative disrupter, is not likely to affect cornified cell envelope crosslinking directly, but seems to interfere with nuclear/nucleolar functions of differentiating keratinocytes. In addition, detection of the mutant loricrin in scraped horny layer could provide a simple noninvasive screening test for loricrin keratoderma. J Invest Dermatol 115:1088-1094 2000

Cell Nucleolus↗

PubMed2000

Modification of the Sauvé-Kapandji procedure with extensor carpi ulnaris tenodesis.

The Sauvé-Kapandji procedure is a useful treatment option for osteoarthritis of the distal radioulnar joint. Recent reports of a painful unstable proximal ulnar stump prompted us to develop a method of stabilizing the proximal stump of the ulna during the Sauvé-Kapandji procedure by using a half-slip of the extensor carpi ulnaris. Thirteen osteoarthritic wrists (8 primary and 5 traumatic) in 8 men and 5 women with an average age of 50 years were treated by this method. The length of the follow-up periods averaged 36 months. Pain improved in all patients after surgery but pain was elicited over 1 ulnar stump by direct pressure. Both pronation/supination and flexion/extension had statistically significant improvement with the exception of flexion. Grip strength improved in all wrists after surgery. Postoperative x-rays improved alignment in both coronal and lateral planes. Stabilization of the proximal ulnar stump associated with Sauvé-Kapandji procedure is a useful procedure to prevent an unstable ulnar stump in the treatment of osteoarthritis of the distal radioulnar joint.

Adult↗

PubMed2000

Suppressed tumorigenicity of human endometrial cancer cells by the restored expression of the DCC gene.

To obtain functional evidence for DCC as a tumour suppressor associated with endometrial cancer, the human DCC cDNA encoding a complete open reading frame (ORF) was transfected into highly tumorigenic human endometrial carcinoma cells, HHUA and Ishikawa in which DCC expression was completely deleted. Reconstituted expression of DCC in HHUA had little effect on in vitro growth, but suppressed tumour formation in mice completely. The clones from Ishikawa had abundant DCC expression similar to that in normal endometrium. Their growth in vitro was suppressed and showed apoptotic phenotype. Lower levels of DCC expression in the prolonged passaged clones did not induce apoptosis, but still had the potential to suppress tumorigenicity. These observations imply a role of DCC in regulation of normal endometrial cell growth, and categorize DCC as the tumour suppressor gene for endometrial cancer.

Animals↗

PubMed2000

Inhibition of apoptosis in human tumour cells by the tumour-associated serpin, SCC antigen-1.

The squamous cell carcinoma antigen (SCC Ag) is a tumour-associated protein and a member of the serine protease inhibitor (serpin) family. The SCC Ag has been used as a serologic tumour marker for SCC progression, and its elevated serum levels are a risk factor for disease relapse. However, the biologic significance of this intracytoplasmic protein in cancer cells remains unknown. In this report, we demonstrated that apoptosis induced by 7-ethyl-10-hydroxycamptothecin, tumour necrosis factor-alpha (TNF-alpha) or interleukin (IL)-2-activated natural killer (NK) cells was significantly inhibited in tumour cells transduced with the SCC Ag-1 cDNA, as compared to control cells in vitro. Also, inhibition of the SCC Ag-1 expression in tumour cells by transfection of antisense SCC Ag-1 cDNA was accompanied by significantly increased sensitivity of these cells to apoptosis induced by etoposide or TNF-alpha. The mechanism of protection of tumour cells from apoptosis involved inhibition of caspase-3 activity and/or upstream proteases. In vivo, tumour cells overexpressing the SCC Ag-1 formed significantly larger tumours in nude mice than the SCC Ag-1-negative controls. Thus, overexpression of the SCC Ag-1, a member of the serpin family, in human cancer cells contributed to their survival by mediating protection from drug-, cytokine- or effector cell-induced apoptosis.

Antigens, Neoplasm↗

PubMed2000

Distraction lengthening of the forearm for congenital and developmental problems.

Thirty-five callus distractions of the forearm were carried out in 23 patients, who were divided into two groups according to the cause of the shortening. Eleven cases in group A had congenital dysplasia, and the 12 cases in group B had growth disturbances from tumours or infection. The mean amount of lengthening was 27 mm in group A and 25 mm in group B. The mean percentage increase in length was 35% and 17%, respectively. The mean duration of fixation was 159 days and 127 days, respectively. The Healing Index had a positive correlation with the age at surgery in group A, but not in group B. The main complication was callus deformity after the removal of a fixator, which was especially frequent in group A. To avoid complications, the aetiology of shortening and the age of the patient should be considered when deciding the surgical protocol.

Adolescent↗

PubMed2000

Does high-resolution MR imaging have better accuracy than standard MR imaging for evaluation of the triangular fibrocartilage complex?

We compared the findings of high-resolution MR imaging and standard MR imaging in the detection of tears of the triangular fibrocartilage in 33 patients with chronic wrist pain on the ulnar side. With arthroscopy as the standard of reference, sensitivity was 100%, specificity 53%, and accuracy 79% with the high-resolution MR imaging, against 83%, 67%, and 76% with the standard MR imaging. High-resolution MR imaging showed a higher sensitivity, but a decreased specificity in the assessment of the triangular fibrocartilage. The results showed that diagnosis of tears in the triangular fibrocartilage by MR imaging, even high-resolution MR imaging, is unsatisfactory, although further technological advances may well improve the accuracy.

Adult↗

PubMed2000

Experimental study of vascularized bone grafts: hypertrophy of the grafted bone.

The mechanism underlying hypertrophy of experimentally vascularized bone grafts was studied in 15-week-old rats. The segmental ulna was grafted to the tibial defect with an external fixator. In experiment 1, 24 rats were classified into four groups to evaluate conventional (non-vascularized), cuff (periosteum-encased, non-vascularized), and vascularized bone grafts, and vascularized segmental grafts with fracture. In experiment 2, 12 rats were classified into two groups according to the presence of mechanical loading. This involved vascularized bone grafts with external fixators, and vascularized bone grafts with external fixators removed after bone union. The bone dynamics of the grafts were investigated by several methods, including roentgenographic analysis, histologic studies, and fluorochrome labeling. In experiment 1, a slight bone formation was recognized in the conventional bone graft, while irregular bone formation with creeping substitution was observed in the cuff graft. The vascularized bone graft showed significant hypertrophy; hypertrophy of the vascularized bone with fracture was greater than that without fracture. In experiment 2, markedly circumferential bone formation was observed after removal of the external fixator, while slight new bone formation was observed during the late postoperative period in bone with an external fixator. These results suggest that hypertrophy can be promoted by artificial fracture of the grafted bone, and that mechanical loading is an important factor for remodeling of grafted bone.

Animals↗

PubMed2000

Studies on congenital protein C deficiency in Japanese: prevalence, genetic analysis, and relevance to the onset of arterial occlusive diseases.

Hereditary protein C deficiency is associated with a predisposition to venous thrombosis. We identified 43 patients with protein C deficiency by screening approximately 26,800 patients admitted to the National Cardiovascular Center Hospital. The observed prevalence of protein C deficiency was 1 per 620. We performed genetic analyses of 57 Japanese families with protein C deficiency. Combined with the results of the other studies in 10 families, the 67 Japanese families with protein C deficiency have been examined and 39 different gene defects have been identified. Some changes were solely identified in Japanese subjects, whereas others showed no such ethnic bias. The recurrent defects of Phe139Val, Arg169Trp, Val297Met, and Met364Ile substitutions and a G8857 deletion were found in 33 Japanese families, accounting for 49% of Japanese families with protein C deficiency, Finally, we examined the relevance of protein C deficiency to the onset of arterial occlusive diseases. In the examination of whether protein C deficiency hastens arterial occlusion, we found a significant difference (p = 0.02) in the age at onset of acute myocardial infarction between the patients with protein C deficiency (n = 10: 49.4 +/- 14.8 years) and a group of patients with normal protein C levels (n = 42: 60.5 +/- 10.6 years). At the onset of atherothrombotic cerebral infarction, the patients with protein C deficiency were significantly (p = 0.022) younger (n = 11:57.4 +/- 12.8 years) than those with normal protein C levels (n = 48: 64.6 +/- 10.1 years). Thus, we conclude that congenital protein C deficiency hastens the onset of arterial occlusive diseases, especially acute myocardial infarction, in Japanese subjects.

Age of Onset↗

PubMed2000

Catheter interventional treatment in Kawasaki disease: A report from the Japanese Pediatric Interventional Cardiology Investigation group.

OBJECTIVE: To assess the current status of catheter intervention in Kawasaki disease and to evaluate its efficacy and outcome. STUDY DESIGN: A questionnaire was sent to 55 major institutions in Japan. RESULTS: A total of 58 procedures in 57 patients were reported. The median age at the time of intervention was 12.1 years. The procedures included percutaneous transluminal coronary angioplasty (PTCA; n = 34), percutaneous transluminal coronary rotational ablation (PTCRA; n = 13), directional coronary atherectomy (DCA; n = 4), and stent implantation (n = 7). The immediate success rate was 74% for PTCA, 100% for PTCRA, 100% for DCA, and 86% for stents. The interval from the onset of disease to intervention in successful PTCA (n = 25) was significantly shorter than that in unsuccessful PTCA (n = 9). Restenosis after PTCA was observed in 24%. Development of new coronary aneurysms was reported in 3 patients for PTCA, 2 for PTCRA, 3 for DCA, and 1 for stents. Except for the DCA, all new aneurysms were associated with the use of high-pressure balloon inflation. Two deaths were reported as acute complications. CONCLUSIONS: Catheter intervention is a promising therapeutic strategy in the management of coronary stenosis caused by Kawasaki disease. Care should be paid to avoid acute coronary arterial complications and the development of new coronary aneurysms.

Adolescent↗

PubMed2000

Shrinkage of perceived tonal duration produced by extra sounds: effects of spectral density, temporal position, and transition direction.

To investigate the mental mechanism that estimates the duration of sounds, the subjective duration of a tone was measured. In the first experiment a portion of the target sound was replaced with another sound. In the second and third experiments another sound either started or ended in the middle of the target sound. Ten or eleven undergraduates participated as listeners in each of the experiments. In the first experiment, effects of spectral spacing and those of temporal position of the replacing sound were tested. Compared with the intact case, the subjective duration of the replaced target shrunk, and the degree of shrinkage increased as the spectral spacing became wider. The temporal position of the replacing sound did not affect the degree of shrinkage. In the second experiment, effects produced by the start (ON) of the concurrent sound and those by the end (OFF) were compared. The ON case was more effective than the OFF case. In the third experiment, effects of the rise time and fall time of the concurrent sound were tested. A long rise and fall time reduced the difference between the ON and OFF cases. These results are discussed from two viewpoints, one assuming an interaction between the time markers, the other assuming continuous gate control in a neural-counting model for duration.

Acoustic Stimulation↗

PubMed2000

Lack of association between TTV viral load and aminotransferase levels in patients with hepatitis C or non-B-C.

TT virus (TTV) is a newly identified un-enveloped single-stranded DNA virus. Although TTV was initially thought to be a new hepatitis virus, it is still unclear whether it causes hepatitis. To clarify the natural history and pathogenesis of TTV infection, serial serum samples from patients with chronic hepatitis were analysed. TTV DNA was quantified by real-time detection polymerase chain reaction assay (RTD-PCR), which was adapted for TTV. Five patients with chronic hepatitis, 4 with hepatitis C and 1 with non-B-C, were studied. The study period ranged from 9 to 50 months. In 3 patients there were frequent increases in TTV DNA titres, but no concomitant elevation of the aminotransferase (ALT) levels. In 2 patients who were treated with interferon, the changes in TTV titres were not synchronized with those of the ALT levels. Thus, in cases of chronic hepatitis, no correlation was observed between the serum TTV DNA titres and the ALT levels.

Adult↗

PubMed2000

In vitro activity of R-95867, the active metabolite of a new oral carbapenem, CS-834, against anaerobic bacteria.

The in vitro activity of R-95867, the active metabolite of a new oral carbapenem, CS-834, was compared with those of DU-6859a, cefditoren, ampicillin/sulbactam and clindamycin against a variety of anaerobic bacteria. R-95867 inhibited 90% of anaerobic strains at </=2 mg/L. In general, R-95867 was 2- to 4-fold less active than DU-6859a but more active than other agents tested against strains of peptostreptococci, clostridia, the Bacteroides fragilis group, Porphyromonas spp. and fusobacteria. R-95867 was stable to hydrolysis by beta-lactamase type 2e derived from B. fragilis, Prevotella bivia and Prevotella intermedia, but unstable to hydrolysis by carbapenemase from B. fragilis.

Bacteria, Anaerobic↗

PubMed2000

Superoxide dismutase expression in the human corpus luteum during the menstrual cycle and in early pregnancy.

To investigate the possible role of the superoxide radical and its scavenging system in the human corpus luteum, superoxide dismutase (SOD) values and lipid peroxide concentrations were analysed in the corpora lutea during the menstrual cycle and in early pregnancy. Copper-zinc SOD (Cu,Zn-SOD) activities increased from the early to mid-luteal phase, and gradually decreased thereafter and were the lowest in the regression phase. In pregnant corpus luteum, Cu,Zn-SOD activities were significantly higher than those in the mid-luteal phase. In contrast, manganese SOD (Mn-SOD) activities were low in the mid-luteal phase and increased toward the regression phase. Changes in mRNA expression of both types of SOD were similar to changes in their activities. Lipid peroxide concentrations were the highest in the regression phase whereas they were remarkably low in pregnant corpus luteum. The effects of human chorionic gonadotrophin (HCG) on luteal SOD were studied in vitro. HCG significantly increased Cu,Zn-SOD expression in mid-luteal phase corpora lutea, but not in late luteal phase corpora lutea. In conclusion, the present study suggests that the superoxide radical and its scavenging system, especially Cu,Zn-SOD, play important roles in the regulation of human luteal function. The stimulation of luteal Cu, Zn-SOD expression by HCG may be important in maintaining luteal cell integrity when pregnancy occurs.

Adult↗