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Biomedical subjects

Kazuhiro Yamada

Publications and source records attributed to Kazuhiro Yamada.

At least 37 records · Page 2Linked to original sources
PubMed2004

Detection of the novel autoantibody (anti-UACA antibody) in patients with Graves' disease.

Uveal autoantigen with coiled coil domains and ankyrin repeats (UACA) is an autoantigen in patients with panuveitis such as Vogt-Koyanagi-Harada disease. The prevalence of IgG anti-UACA antibodies in patients with uveitis is significantly higher than healthy controls, suggesting its potential role as an autoantigen. Originally, UACA was cloned from dog thyroid tissue following TSH stimulation. So, we presumed UACA could be a novel autoantigen in autoimmune thyroid diseases. We measured serum anti-UACA antibody titer using ELISA in patients with autoimmune thyroid diseases (Graves' disease, Hashimoto's thyroiditis, subacute thyroiditis, and silent thyroiditis). The prevalence of anti-UACA antibodies in Graves' disease group was significantly higher than that in healthy group (15% vs. 0%). Moreover, the prevalence of anti-UACA antibodies in Graves' ophthalmopathy was significantly higher than that in Graves' patients without ophthalmopathy (29% vs. 11%). Especially, 75% of severe ocular myopathy cases showed high UACA titer. Immunohistochemical analysis revealed that UACA protein is expressed in eye muscles as well as human thyroid follicular cells. Taken together, UACA is a novel candidate for eye muscle autoantigens in thyroid-associated ophthalmopathy.

Adult↗
PubMed2004

Multilevel phase-type diffractive lenses in silica glass induced by filamentation of femtosecond laser pulses.

Multilevel phase-type diffractive lenses were fabricated by translating a filament of a femtosecond laser pulse into three-dimensional space inside synthesized silica. The profile of the lenses was designed by use of a multi-level approximation to a kinoform lens. Two-level diffractive lenses with multiple layers along the optical axis provided a maximum efficiency of 37.6% at a wavelength of 632.8 nm. A four-level diffractive lens provided a maximum efficiency of 56.9%. The lenses fabricated with filamentation were free from birefringence.

Journal Article↗
PubMed2004

Development of an ultrasensitive enzyme immunoassay for human proadrenomedullin N-terminal 20 peptide and direct measurement of two molecular forms of PAMP in plasma from healthy subjects and patients with cardiovascular disease.

OBJECTIVE: Proadrenomedullin N-terminal 20 peptide (PAMP) processed from an adrenomedullin precursor is a potent hypotensive peptide. It was anticipated that a mature form of PAMP (m-PAMP) and an intermediate PAMP-gly existed together in the blood. To measure concentrations of PAMPs in human plasma directly, we have developed a highly sensitive enzyme immunoassay (immune complex transfer enzyme immunoassay, ICT-EIA). DESIGN AND METHODS: PAMP was reacted simultaneously with 2,4-dinitrophenyl (DNP)-biotinyl-bovine serum albumin (BSA)-anti-PAMP Fab' conjugate and anti-PAMP Fab'-beta-D-galactosidase conjugate. The immune complex that was formed was initially trapped onto a polystyrene bead coated with anti-DNP IgG, and then transferred onto a second polystyrene bead coated with streptavidin. The resulting three-component complex was then assayed fluorometrically. RESULTS: The detection limits of ICT-EIA for both m-PAMP and PAMP-gly were 0.1 pmol/l with as little as 10 microl of plasma, and were a hundred times higher than with conventional radioimmunoassay (RIA). Using ICT-EIA, we determined that the plasma concentrations of m-PAMP and PAMP-gly in 51 healthy volunteers were 0.51 +/- 0.19 and 1.15 +/- 0.38 pmol/l (mean +/- SD), respectively. Both plasma m-PAMP and PAMP-gly concentrations in patients with a variety of diseases, including hypertension, heart failure, chronic renal failure, and hemodialysis, were significantly higher than those in healthy subjects. In addition, both plasma m-PAMP and PAMP-gly concentrations in patients with New York Heart Association (NYHA) class I-IV heart failure were increased in proportion to clinical severity. CONCLUSIONS: These sensitive and specific ICT-EIAs may be used as a powerful tool for investigating the cardiovascular system in patients with heart failure.

Adrenomedullin↗
PubMed2004

Three-dimensional structural views of branch migration and resolution in DNA homologous recombination.

The processing of the Holliday junction by various proteins is a major event in DNA homologous recombination and is crucial to the maintenance of genome stability and biological diversity. The proteins RuvA, RuvB and RuvC play central roles in the late stage of recombination in prokaryotes. Recent atomic views of these proteins, including protein-protein and protein-junction DNA complexes, provide new insights into branch migration mechanisms: RuvA is likely to be responsible for base-pair rearrangements, whereas RuvB, classified as a member of the AAA(+) family, functions as a pump to pull DNA duplex arms without segmental unwinding. The mechanism of junction resolution by RuvC in the RuvABC resolvasome remains to be elucidated.

Bacterial Proteins↗
PubMed2004

Relationship between serum IgA/C3 ratio and progression of IgA nephropathy.

OBJECTIVE: The serum IgA/C3 ratio might be considered to serve as a diagnostic marker for patients with IgA nephropathy (IgAN), but its value as a marker of the severity of histological lesions or prognosis is unknown. METHODS: We studied the serum IgA/C3 ratio, using standardized reference material, in 86 patients with IgAN and in 32 with non-IgAN. The patients with IgAN were divided according to the severity of histological lesions (mild IgAN, n=29 and severe IgAN, n=57) based on Japanese clinical guidelines. RESULTS: The serum IgA level was significantly higher, while its C3 level was lower in patients with severe IgAN compared to those with non-IgAN. However, these levels were not different between patients with mild IgAN and non-IgAN. In contrast, the serum IgA/C3 ratio obviously differed among the three groups (2.47+/-0.96 vs. 3.63+/-1.44 vs. 4.72+/-1.86; p<0.01, ANOVA). Kaplan-Meier analysis of the patients with IgAN classified according to the mean serum IgA/C3 ratio revealed that the group with high serum IgA/C3 (4.5 and above) had a significantly poorer renal outcome (p<0.05, log-rank test), since the cumulative renal survival rate at 5 years was 84.4% vs. 100%. The ratio (%) of patients with severe IgAN in whom hematuria disappeared, was significantly higher in the low, than in the high serum IgA/C3 group (41.9% vs. 15.4%; p<0.05, t-test). CONCLUSION: The serum IgA/C3 ratio appears to reflect the histological severity of IgAN and could serve as a marker of the progression of IgAN.

Adult↗
PubMed2004

Nephrotic syndrome caused by membranous nephropathy: response to a short course of cyclophosphamide alternating with prednisolone.

OBJECTIVE: The optimal duration of immunosuppressive therapy and the timing of treatment for treating membranous nephropathy (MN) have yet to be established. We examined outcomes of a short course of cyclophosphamide alternating with prednisolone for MN patients with nephrotic syndrome. METHODS AND PATIENTS: Cyclophosphamide (2 mg/kg/day for 8 weeks) combined with prednisolone (1 mg/kg every 48 hours for 8 weeks, then tapering off for 1 year) was prescribed for 28 MN patients (12 men and 16 women; mean age 52.4+/-2.25 years SEM). We first evaluated the response rates to this combined therapy, then compared the clinical characteristics of those who achieved remission (group A) with those who did not (group B) within 6 months of the start of treatment. RESULTS: The incidences of complete and partial remission increased with the follow-up period; 32 and 21% by 6 months, 54 and 29% by 12 months, and 79 and 11% by 24 months, respectively. Serum IgG (906+/-100.8 versus 562+/-66.1 mg/day; p<0.01) was significantly higher in group A, and the selectivity index (C(IgG)/C(albumin) 0.16+/-0.015 versus 0.30+/-0.040; p<0.01), significantly lower. Nephrotic syndrome persisted in 3 group B patients (23%), who finally had impaired renal function. CONCLUSION: MN patients with nephrotic syndrome responded favorably to a short course of cyclophosphamide combined with prednisolone. The serum IgG level and selectivity index may serve as markers of early response to this treatment.

Biopsy, Needle↗
PubMed2004

Minimal change nephrotic syndrome after allogenic hematopoietic stem cell transplantation.

We describe a 24-year-old man who developed minimal change nephrotic syndrome after allogenic hematopoietic stem cell transplantation (HSCT). One year after undergoing allogenic peripheral blood stem cell transplantation (PBSCT), this patient presented with proteinuria. He also presented with skin and lip lesions considered to be chronic graft-versus host disease. Observation of renal biopsy specimens by light microscopy revealed minor glomerular abnormalities. However, electron microscopy disclosed focal mesangial interposition, irregular thickening of the glomerular basement membrane and subendothelial loosening. Two years after HSCT, the patient developed nephrotic syndrome. Long use of cyclosporine improved the proteinuria and hypoalbuminemia within 12 months.

Adult↗
PubMed2004

[Head and neck reconstruction using laparoscopically harvested omentum].

Since the need for laparotomy in harvesting the omentum is the most significant drawback, the omentum has not been the tissue of choice for reconstructive surgery. To compensate for this drawback, we started laparoscopic harvesting of the omentum and clarified the advantages and disadvantages of this procedure. Ten patients underwent laparoscopic harvesting of the omentum by abdominal surgeons, followed by reconstruction of head and neck defects. Surgery was conducted in 5 cases of defect reconstructions for parotid gland tumor surgery and 5 of oropharyngeal defect after cancer surgery. The average harvesting time was 107 minutes (55-140 minutes) and used the omentum and different amounts and length of the vascular pedicle. Although the omentum was successfully transplanted in 9 of 10 cases, 2 cases showed partial peripheral necrosis and 1 total necrosis. With the advantage of laparoscopic harvesting of the omentum, we could obtain appropriate omental size for the defect size. Especially after total parotidecomy, the omentum was useful to fill in the defect, reducing the patients' worries about postoperative deformity. In one case, the omentum was used to treat Frey syndrome, successfully relieving the symptoms. In oropharyngeal reconstruction, the omentum is used to fill dead space and prevented postoperative infection. Although mild abdominal pain was observed a few days after surgery, no major abdominal complications such as intestinal perforation or ileus occurred in the 8 to 39 months following laparoscopic harvest of the omentum. Since the omentum is pliable and easily fills a complicated defect, the omentum is considered satisfactory for reconstructing defects of the lateral face after parotid tumor surgery and small defects after oropharyngeal tumor surgery.

Aged↗
PubMed2004

The relationship between morphological changes of the condyle and condylar position in the glenoid fossa.

AIMS: To investigate whether condylar morphological changes influence the condyle position in the glenoid fossa as well as the amount of condylar movement from the intercuspal position (IP) to the reference position (RP). METHODS: Helical computed tomography was used for precise measurement of the joint spaces at IP and RP in 22 subjects (mean age 22.7 years). Subjects were divided into 2 groups, those without condylar bone changes (n = 11) and those with condylar bone changes (n = 11). The latter group was further subdivided into a flattening subgroup and an osteophyte subgroup, according to the type of condylar bone change. RESULTS: There were no significant differences in the width of the anterosuperior or posterosuperior joint spaces at IP between either the 2 groups or the 2 subgroups. On the other hand, during condylar movement from IP to RP, the condyles moved significantly more superiorly and posterosuperiorly in the bone-change group than in the no-bone-change group. There was also greater absolute horizontal condylar movement between IP and RP in the bone-change group. In addition, within the bone-change group, the type of condylar bone change influenced the amount of condylar movement. Joints with osteophyte formation showed the most superior, posterosuperior, and absolute horizontal movement from IP to RP. CONCLUSION: The findings that condyles of the bone-change group, especially those with osteophyte formation, were located significantly more anteroinferiorly in the glenoid fossa at IP than RP than the condyles of the no-bone-change group suggest that condylar IP-RP positional changes might be related to condylar shape alteration.

Adult↗
PubMed2003

Wavelength division with three-dimensional couplers fabricated by filamentation of femtosecond laser pulses.

Refractive-index changes can be induced by filamentation of 800-nm, 1-kHz femtosecond laser pulses in silica glass. Two-dimensional translation of a 40-microm-long filament leads to the formation of a curved waveguide because of bending by the previously induced refractive-index change. The fabrication of 2-mm directional couplers to split the coupled beam into 1:1 at a wavelength of 632.8 nm is demonstrated. The realization of three-dimensional directional couplers and wavelength division in the output from the couplers is also demonstrated.

Journal Article↗
PubMed2003

Calcium binding to troponin C as a primary step of the regulation of contraction. A microcalorimetric approach.

Microcalorimetric titration studies of EF-hand Ca-binding proteins (troponin C, calmodulin and parvalbumins) resulted in the notion that Ca binding to the "active" Ca site, which is involved in the regulation of contraction, induces a characteristic anomalous enthalpy and heat-capacity changes indicating an exposure of hydrophobic residues to the solvent, which enables the proteins to interact with their targets. There is a good agreement between the results of the calorimetric and the structural studies in frog and chicken skeletal troponin C. In both species one of the N-terminal low-affinity Ca-sites is the "active" Ca site regulating muscle contraction. The results from calorimetry have shown, however, that the situation in rabbit skeletal troponin C may be more complex. Moreover, in both calorimetric and structural studies, the situation in cardiac troponin C is quite different. These results suggest the need for further studies to elucidate the mechanism of regulation by Ca. These characteristic changes do not occur in Ca-buffering proteins.

Actin Cytoskeleton↗
PubMed2003

A case of primary B-cell type non-Hodgkin lymphoma originating in the iris.

PURPOSE: To report a case of primary malignant B-cell type non-Hodgkin lymphoma originating in the iris. DESIGN: Interventional case report. METHODS: An 83-year-old woman presented with anterior uveitis resulting from primary malignant lymphoma in the iris. Ultrasound biomicroscopy and indocyanine green angiography using a scanning laser ophthalmoscope showed abnormalities in the iris. Diagnostic biopsy of the iris revealed B-cell type non-Hodgkin lymphoma. RESULT: The patient was treated with radiotherapy, and the tumorous lesion resolved. CONCLUSION: Primary lymphoma localized in the iris only is rare. In this case, diagnostic biopsy and radiotherapy of the iris lymphoma provided good results.

Aged↗
PubMed2003

Delivery of medical multimedia contents through the TCP/IP network using RealSystem.

We developed a low cost, user-friendly multimedia delivery system, to provide medical lectures saved as multimedia contents to persons engaged in medicine. This system was created using the RealSystem package with the TCP/IP network. Users can review lectures and medical meeting presentations with video and audio through the Internet, whenever convenient. Each medical source of video and slide has been clearly displayed on a screen. Members of medical associations or medical students can easily review the most interesting parts of these files. This system is being used efficiently in distance learning and aids the diffusion of the latest information and technology to busy physicians and medical students.

Computer-Assisted Instruction↗
PubMed2003

Single-action implantation of a 3-piece acrylic intraocular lens with an injector.

We report a method to insert a 3-piece AcrySof MA30BA acrylic foldable intraocular lens (IOL) (Alcon) in a single action using a Monarch II (Alcon) injector. The technique was used in 134 eyes. The incision widths ranged from 3.00 to 3.75 mm. The IOLs were successfully inserted in the capsular bag. Complications included cracks in the IOL optic in 3 eyes (3%), haptic damage in 3 eyes (3%), and inadequate self-sealing of the incision in 18 eyes (13%).

Acrylic Resins↗
PubMed2003

Relationship between facial asymmetry and masseter reflex activity.

PURPOSE: In this study, we evaluated the tonic vibration reflex (TVR) of the masseter muscles in patients with facial asymmetry. SUBJECTS AND METHODS: The study was conducted with 10 volunteers without facial asymmetry and 12 orthognathic patients with facial asymmetry. Subjects were seated in a chair and held a stimulator composed of an electric motor and an acrylic bite block between the upper and lower dentitions at facial midline, to elicit TVR. Electromyographic activity was recorded using a pair of silver electrodes affixed bilaterally with adhesive tape to the skin over the superficial masseter. The amount of mandibular deviation was measured on the frontal cephalogram. The reflex response was evaluated with the following: TVR index (%) = integral TVR x 100/ integral maximum voluntary contraction (MVC), and with the TVR ratio: integral TVR on the high MVC side/ integral TVR on the low MVC side. RESULTS: In the patient group, the average TVR index on the deviated side was significantly higher than that on the nondeviated side. In all subjects, including the control and patient groups, a negative correlation between the amount of mandibular deviation and the side-to-side difference in TVR index was seen (r = -0.536, P <.05, n = 22). In addition, patients with a lower MVC on the deviated side than on the nondeviated side showed a significantly higher TVR ratio than did the control group. CONCLUSIONS: These results suggest that the difference between the right and left reflex responses elicited by TVR might be related to frontal craniofacial morphology.

Adult↗
PubMed2003

The relationship between retruded contact position and intercuspal position in patients with TMJ osteoarthritis.

This study was conducted to investigate the relationship between posterior mandibular excursion movement and temporomandibular joint osteoarthntis (TMJ OA) in 25 orthodontic patients with Angle Class I and Class II, using a six degrees-of-freedom measuring device and helical computed tomography. There were significant differences found in three-dimensional length, antero-posterior, absolute latero-medial and supero-inferior incisal, and condylar intercuspal position (IP)-retruded contact position (RCP) slides between bilateral, unilateral, and no condylar bone change groups. With respect to the types of condylar bone change, there were significant differences found in three-dimensional length, antero-postenor, and absolute latero-medial condylar IP-RCP slides between flattening, erosion and osteophyte groups. These results suggest that large three-dimensional, not only incisal but also condylar, IP-RCP slides might be related to the uni-/bilaterality and kind of TMJ pathosis, which might make such slides useful as clinical indices of TMJ OA.

Adult↗
PubMed2003

Case report: Extraocular muscle paresis caused by snakebite.

A 51 year-old man presented with binocular diplopia on the three days after the snakebite in the fifth finger of the right hand by an Agkistrodon blomhoffi (mamushi). In the primary position he had an exotropia and right hypertropia, which became apparent when his head was tilted to the right. From ocular angle of deviation measured by synoptophore and Hess chart test, he was diagnosed as having medial rectus muscle paresis as well as inferior oblique muscle paresis of the left eye. Elevation deficit on right gaze in the left eye had remained during three days. Our case suggested that the occurrence of subjective binocular diplopia is an important clinical sign for the onset of general abnormalities caused by snakebite.

Animals↗