Biomedical subjects

H Iwata

Publications and source records attributed to H Iwata.

At least 361 records · Page 20Linked to original sources

PubMed1996

Idiopathic spinal cord herniation.

Idiopathic spinal cord herniation is a rare disease, few cases having been reported. We encountered a case of idiopathic spinal cord herniation presenting with severe spasticity in the right leg and urinary dysfunction. The spinal cord was herniated into a cavity created by duplication of the dura mater and resection of the inner layer improved the neurological deficits. MRI, myelography, and CT myelography were useful for diagnosing this disease. Four radiological signs of spinal cord herniation are described.

Dura Mater↗

PubMed1996

Embolization of cerebral aneurysms with a liquid embolus, EVAL mixture: report of three cases.

Embolization of three surgically difficult cerebral aneurysms was performed using our newly developed non-adhesive embolic material, EVAL mixture (ethylene vinyl alcohol copolymer). Conventional embolic materials such as detachable balloons or microcoils were not used because of a large or irregular aneurysmal neck. After temporary occlusion of the parent artery with a superselective balloon catheter, the EVAL mixture was slowly injected through a microcatheter placed in the aneurysm or parent artery. The locations of the aneurysms were anterior communicating artery, basilar artery-posterior cerebral artery and basilar artery-anterior inferior cerebellar artery (BA-AICA). One aneurysmal occlusion and 2 parent artery occlusions were performed. Patients had no persistent deficits. The patient with the BA-AICA aneurysm associated with an arteriovenous malformation died of rupture of the residual AVM due to haemodynamic change 2 weeks after embolization. In selected and limited cases, embolization of surgically difficult cerebral aneurysms using EVAL mixture was more effective and safer than embolization using conventional embolic materials such as balloons and microcoils.

Adult↗

PubMed1996

Mucopolysaccharidosis IVA: a comparative study of polymorphic DNA haplotypes in the Caucasian and Japanese populations.

Mucopolysaccharidosis IVA (MPS IVA) is an autosomal recessive disorder caused by deficiency of the lysosomal enzyme N-acetylgalactosamine-6-sulphate sulphatase (GALNS). The genetic heterogeneity at the GALNS locus was studied in 62 mutant alleles and 376 normal alleles in the Caucasian population and also in 40 mutant and 100 normal alleles in the Japanese population. For this study, six different restriction fragment length polymorphisms (RFLPs) at the GALNS locus were analysed to search for the frequency of each RFLP produced by StyI, SphI, RsaI, HaeIII, StuI and HapII restriction endonucleases. We detected a total of 27 haplotypes in the Caucasian and Japanese population. Of these 27 haplotypes, 18 haplotypes were present in the Caucasian population and the most common of these was haplotype 1 (ABHcde) in both mutant and normal alleles. In contrast, in the Japanese population we found 20 of the 27 haplotypes and the most common in mutant and normal alleles was haplotype 2 (abhcDE). Within these two populations a parent in the MPS IVA family has an average probability of greater than 77% (in the Caucasian population 77.27% and in the Japanese population 78.26%) of being heterozygous, and hence informative for linkage, at one or more GALNS RFLP sites. Our results delineate the molecular heterogeneity of MPS IVA haplotypes, as well as their significant interpopulation variation, and make prenatal diagnosis and carrier detection possible in the majority of families with one affected child.

Acetylgalactosamine↗

PubMed1996

A cationic polymer, Eudragit-E, as a new liquid embolic material for arteriovenous malformations.

We have developed a new liquid material for embolisation of arteriovenous malformations: a mixture of methyl and butyl methacrylate, plus dimethylaminoethyl methacrylate copolymer (Eudragit-E) in a solvent consisting of ethanol and iopamidol. Upon contact with aqueous substances, Eudragit-E precipitates rapidly and forms a soft elastic sponge within 3 s, as the ethanol diffuses. In blood, the positively charged Eudragit-E aggregates the negatively charged blood elements. Transcatheter embolisation of 4 canine and 52 rat renal arteries was feasible. Histological studies revealed no acute inflammatory reaction within 1 week, but mild to moderate reactions in the subacute and chronic stages. No recanalisation was seen. Because of its unique properties and excellent thrombogenicity the Eudragit-E, mixture seems a promising embolic material.

Analysis of Variance↗

PubMed1996

Inflammatory reaction in chondroblastoma.

OBJECTIVE: The objective of this study was to evaluate the inflammatory reaction accompanying chondroblastoma and to define the value of the finding in clinical practice. DESIGN: We reviewed the clinical, radiographic, and magnetic resonance (MR) findings in six patients with histologically proven chondroblastoma. RESULTS: In all cases, MR imaging showed marrow and soft tissue edema. In four of six cases, periosteal reaction related to intra-osseous edema was more clearly demonstrated on MR imaging than on radiographs. Follow-up MR studies after surgery were available in three patients and all showed disappearance of inflammatory responses such as marrow and soft tissue edema, and reactive synovitis. CONCLUSION: We propose that these inflammatory reactions of chondroblastomas are important signs for detecting residual tumor in recurrences after surgery, as well as for making a precise diagnosis. The MR changes may also be valuable in demonstrating eradication of the tumor.

Adolescent↗

PubMed1996

Cementless total hip arthroplasty with autologous bone grafting for hip dysplasia.

The fate of autologous femoral head bone grafts in acetabular roof reconstruction for severely dysplastic hips was investigated in 25 patients (25 cementless total hip arthroplasties). Twenty patients were women and 5 were men, whose average age was 55 years old; their average followup was 58 months. The average Harris Hip Rating improved from a preoperative value of 49 points to a postoperative value of 85 points. Radiographic measurements did not indicate any vertical or horizontal socket migration >2 mm. The grafted bone was incorporated by an average time of 7 months, and the acetabular sclerosis had disappeared in 23 hips by 9.4 months. One year after operation, the grafted bone was reduced in size significantly. Radionuclide uptake at the site of the bone graft remained high for as long as 18 months after the operation, then normalized. The autologous acetabular bone grafts were incorporated completely and remodeled 18 months after surgery.

Acetabulum↗

PubMed1996

Successful treatment of chylothorax by bleomycin for Gorham's disease.

A patient with idiopathic osteolysis in the thoracolumbar spine who developed severe chylothorax after a spinal operation is described. Irradiation and pleural adhesion therapies with minocycline and bleomycin were undertaken to control the chylothorax. Pleural adhesion therapy with bleomycin proved effective in treating this patient. Magnetic resonance imaging was performed to detect the lesion. T1 weighted imaging was particularly useful in diagnosing the lesion and evaluating the degree of fusion in the spine.

Adult↗

PubMed1996

Twenty years' followup of intertrochanteric osteotomy for treatment of the dysplastic hip.

A followup study of more than 15 years of intertrochanteric osteotomy for osteoarthrosis of the dysplastic hip was performed in 52 hips of 42 patients with varus osteotomy and in 58 hips of 53 patients with valgus osteotomy. Varus osteotomy was indicated for predegenerative or early degenerative stages of osteoarthrosis, and valgus osteotomy was indicated for progressive or end stage disease. The average age at time of varus and valgus osteotomies was 25 and 37 years, respectively, and the average followup period was 21 and 20 years, respectively. Using Kaplan-Meier's method (end point, Harris Hip Score < 70 points or salvage operation), the 10- and 15-year survival rates for varus osteotomy were 89% and 87% and for valgus osteotomy were 66% and 38%, respectively. Radiographic measurements of the postoperative acetabular head index and center edge angle in varus osteotomy were better in the group with good results than those in the group with poor results. There were no differences in radiographic measurements between the group with good results and the group with poor results of valgus osteotomy. Intertrochanteric varus and valgus osteotomy delayed the need for total hip arthroplasty in young patients with osteoarthrosis of the dysplastic hip.

Adolescent↗

PubMed1996

Comparison of calbindin D-28k and S-100 protein B in neuroblastoma as determined by enzyme immunoassay.

Levels of two calcium-building proteins, calbindin D-28k (calbindin-D) and S-100 protein B (S-100b), were measured by immunoassay in solid tumors obtained surgically from pediatric patients. Mean concentrations of calbindin-D and S-100b in 73 neuroblastomas (23 ganglioneuroblastomas and 50 neuroblastomas) were 10- or 25-fold higher, respectively, than those in other types of solid tumors in pediatric patients (n = 15). The mean tumor concentration of calbindin-D in patients with neuroblastoma (n = 73) was 25.1 ng/mg (range 0.20 to 317.0 ng/mg soluble protein, SE = 6.26); that of S-100b was 278.3 ng/mg (range 0.93 to 2521 ng/mg soluble protein, SE = 71.7). The mean concentration of calbindin-D (4.4 ng/mg soluble protein) was significantly (P < 0.05) lower in stage IV, the most advanced stage. The mean concentration of S-100b (74.0 ng/mg soluble protein) was lower in patients with undifferentiated neuroblastomas (P < 0.01). Tumor levels of the two calcium-binding proteins were not correlated in patients with neuroblastoma, but each was strongly correlated with outcome in patients with neuroblastoma. The evidence suggests that measurements of the calcium-binding proteins calbindin-D and S-100b would be useful for evaluating the prognosis of patients with neuroblastoma.

Adolescent↗

PubMed1996

Production of matrix metalloproteinases and tissue inhibitors of metalloproteinases in human breast carcinomas.

We examined production and tissue localization of matrix metalloproteinase (MMP)-1 (tissue collagenase), MMP-2 (gelatinase A), MMP-3 (stromelysin-1), MMP-9 (gelatinase B), tissue inhibitors of metalloproteinase (TIMP)-1 and TIMP-2 in human breast carcinomas. In more than half of the cases, MMP-1, MMP-2, MMP-9, TIMP-1 and TIMP-2 were immunolocalized in carcinoma cells and MMP-2 was on the carcinoma cell membranes as well, whereas MMP-3 was positively stained in less than 15% of the cases. MMP-1 staining in carcinoma cells was significantly higher in scirrhous carcinoma than in other types of carcinoma. MMP-9 expression was remarkably higher in the carcinoma cases with lymphnode metastasis than in the non-metastatic cases. MMP-3 was mainly expressed in T-lymphocytes infiltrated in the tumor stroma. Stromal fibroblasts were positive for all these MMPs except for MMP-3. The TIMP-1 levels released into the culture media by carcinoma tissues were significantly lower than those by fibroadenoma tissues, although there were no significant differences in the levels of MMP-1, MMP-2, MMP-9 and TIMP-2. Gelatin zymographical analyses showed that the activation rate of the zymogen of MMP-2 (proMMP-2) is significantly higher in the more advanced carcinoma group with lymphnode metastasis than in the metastasis-negative and fibroadenoma groups. These data indicate that MMP-1, MMP-2 and MMP-9 are highly expressed in human breast carcinoma tissue and suggest that activation of proMMP-2 may be an indicator of lymphnode metastasis of the breast carcinoma.

Breast Neoplasms↗

PubMed1996

Evidence of direct recognition subset in xeno-reactive helper T cells.

There are two functional subsets of alloreactive helper T cells: one recognizes the alloantigens on self-antigen-presenting cells (APCs), and the other recognizes the alloantigens on allo-APCs. In this study, we analyzed which specific Th cells have a possible effect on concordant-xenograft rejection responses and how Th cells recognize xeno-antigens. In the proliferative response stimulated with spleen cells obtained from rats (r-SPC), mouse T cells (m-Tc) were not inhibited by GK1.5 (CD4) or 2.43 (CD8) antibodies. In a xeno-mixed lymphocyte reaction, m-Tc that included APC (APC(+)) proliferated when stimulated with r-SPC APC(+) or APC(-). In contrast, B6 T cell APC(-) proliferated only when stimulated with r-APC(+)SPC but not when stimulated with APC(-). The m-Tc lines responded to F344 SPC APC(+) but not to SPC APC(-); however, the m-Tc line did not respond to SPC from another rat strain. We hypothesize that both CD4+ Th and CD8+ Th are included in the concordant xeno-reactive Th; there are both xeno-APC-restricted Th and self-APC-restricted Th; and xeno-APC-restricted Th recognizes xeno-major histocompatibility complexes.

Animals↗

PubMed1996

Comparison among performances of a ligase chain reaction-based assay and two enzyme immunoassays in detecting Chlamydia trachomatis in urine specimens from men with nongonococcal urethritis.

We evaluated the performances of a ligase chain reaction (LCR)-based assay and two enzyme immunoassays (Chlamydiazyme and IDEIA) in the detection of Chlamydia trachomatis in urine specimens. We compared the results of testing urine specimens by these assays with those of urethral swab culture by examining samples from 131 men with nongonococcal urethritis. Discrepant results were analyzed by testing urethral swab specimens for C. trachomatis by a PCR-based assay. After the resolution of discrepant results, the sensitivity of urethral swab culture was 85.3%, whereas those of the LCR assay, Chlamydiazyme, and IDEIA with urine specimens were 94.1, 82.4, and 94.1%, respectively. The LCR assay and IDEIA were more sensitive than was urethral swab culture. In addition, the LCR assay, with a sensitivity equal to that of IDEIA, was more specific. Overall, the LCR assay proved to be superior to the enzyme immunoassays in detecting C. trachomatis in urine specimens. Testing urine specimens by LCR assay should be a helpful alternative method for diagnosing C. trachomatis urethral infection in men with nongonococcal urethritis.

Chlamydia Infections↗

PubMed1996

An immuno-isolative membrane capable of consuming cytolytic complement proteins.

In an earlier article we demonstrated that xenogeneic islets of Langerhans in an agarose/poly(styrenesulfonic acid) (PSSa) microcapsule were protected from the host's immune rejection and that diabetic animals maintained a normal glucose level for a long period of time after their transplantation. In this study, we attempted to make clear the immuno-isolative mechanisms of the agarose-PSSa microcapsule from the standpoint of permeability of antibodies and complement proteins through this microcapsule membrane. It was found that the microcapsule was unable to prevent the permeation of IgG for longer than a few days, but protect the encapsulated cells from cytolytic complement attack. This strongly suggests that the cytolytic complement activity was lost during permeation through the microcapsule, probably because of the strong interaction of PSSa in the membrane with complement proteins. Based on these findings we proposed the minimum requirement for the immuno-isolative membrane to be applicable to xenotransplantation.

Animals↗

PubMed1996

Effects of long-term oral administration of amiodarone on the ventricular repolarization of rabbit hearts.

The chronic effects of amiodarone on ventricular repolarization were investigated in Langendorff-perfused rabbit hearts in comparison with the acute effects of other Class III antiarrhythmic drugs. Forty to fifty electrograms were recorded through modified bipolar electrodes from the anterior to the lateral epicardial surface of the ventricles under His-bundle pacing (1.0 Hz). In control hearts, epicardial activation proceeded from the apex to the base. The interval from the initial sharp negative deflection of the QRS complex to the apex of the T-wave (Q-aT), which reflects the action potential duration (APD) at the recording site, was longest in the apex and shortest in the base. Therefore, repolarization proceeded from the base to the apex. In hearts treated with oral amiodarone (100 mg/kg, 4 weeks), Q-aT was uniformly prolonged by 14-16% throughout the entire mapped area, whereas the activation sequence was unaffected, and a normal Q-aT gradient was well preserved from the apex to the base. The spatial inhomogeneity of left ventricular repolarization was not enhanced by drug treatment. Acute application of sotalol (30 mumol/L), E-4031 (0.1 mumol/L) or MS-551 (1.0 mumol/L) caused a much greater Q-aT prolongation in the apex than in the base, resulting in a marked enhancement of the spatial inhomogeneity of repolarization. These findings suggest that the propensity of chronic amiodarone to induce torsade de pointes less often than other Class III agents may result at least in part from its favorable effect on the spatial homogeneity of ventricular repolarization.

Administration, Oral↗

PubMed1996

[Monoclonal antibody against an urinary protein secreted from the renal tubules--immunohistochemical analysis of renal cell carcinoma].

BACKGROUND: Monoclonal antibodies (mABs) against urinary proteins originated from renal tubules were obtained in order to find a possible tumor marker for renal cell carcinoma. METHODS: Urine samples were collected from healthy adult males. After removal of Thamm-Horsfall protein (THP) by sodium chloride precipitation, supernatant urine was ultrafiltered, thus, THP-free urinary proteins were obtained. Then, proteins of plasma origin were removed by circulating the urinary proteins through an affinity column which contained immobilized rabbit anti-human whole serum immunoglobulins. BALB/c mice were immunized with the THP- and plasma protein-free urinary proteins. The spleen cells were fused with mouse myeloma cells. Hybridomas were screened by indirect immunofluorescence of fresh frozen kidney tissue sections using culture supernatants. RESULTS: Five hybridomas producing mAbs which reacted with renal tubular segments were established. One mAb reacted strongly with distal renal tubules. Using this mAb, formalin fixed and paraffin embedded sections of 39 renal cell carcinomas were stained by immunoperoxidase method. Twenty-six of the 39 cancer tissues (66.7%) were stained positive. According to the histological classification, positive staining rate of clear cell subtype, and mixed subtype was 75% (6/8), 80% (8/10) and 66.7% (6/9), respectively. According to the tumor grade, positive staining rate of G1, G2, G3 was 66.7% (6/9), 71.4% (15/21) and 55.5% (5/9), respectively. CONCLUSION: These findings indicate that most of renal cell carcinomas were originated from common precursor cells for both proximal and distal tubules, because normal proximal tubular cells were not stained by the mAb.

Adult↗

PubMed1996

Effects of bisphosphonate on bone metabolism in tail-suspended rats.

Our previous studies demonstrated that tail suspension causes early, transient increases in osteoclastic activity, followed by a decrease in osteoblastic activity in the hind limbs of rats. To assess whether this early increase in bone resorption is important in the development of disuse atrophy, the effect of YH529, a third generation bisphosphonate, was studied on hind limb atrophy in rats subjected to tail suspension. YH529 (YH group) or PBS (control group) were administered subcutaneously in 5-week-old male Wistar rats suspended for 7 days. In the control group, wet weight, calcium and phosphorus contents decreased significantly in the femur but they did not change in the humerus. In the YH group, however, these parameters did not change significantly in the femur, but both calcium and phosphorus increased significantly in the humerus. These results indicate that the inhibition of bone resorption by YH529 prevents the development of disuse atrophy induced by tail suspension. It is thus suggested that early increases in bone resorption are important for the development of disuse bone atrophy.

Animals↗

PubMed1996

Changes in serum concentrations of calcium and its regulating hormones during tail suspension in rats.

To study the effects of mechanical unloading on systemic calcium homeostasis, we determined the changes in serum concentration of calcium, 1,25-dihydroxyvitamin D3 and parathyroid hormone (PTH) during tail-suspension experiments in rats. The serum concentration of ionized calcium significantly increased during the 14 days of the suspension, reflecting increased bone resorption in the hind limbs. This hypercalcemic condition should cause suppression in PTH secretion. Indeed, serum PTH levels decreased on Day 3 of the suspension. This decrease was associated with lower serum levels of 1,25-dihydroxyvitamin [correction of dihyroxyvitamin] D3 probably due to a decrease in the activity of 1 alpha-hydroxylase in the kidneys resulting from a decrease in PTH secretion. Since it is known that 1,25-dihydroxyvitamin D3 stimulates osteoblastic function, it is suggested that endocrine responses evoked by tail suspension aggravate disuse atrophy of the hind limbs.

Amino Acids↗

PubMed1996

[Encapsulated dopamine-secreting cells transplanted into the brain: a possible therapy for Parkinson's disease].

Encapsulation of neurosecretory cells within a semipermeable membrane may possibly isolate the enclosed cells from the host immune system and allow inward diffusion of nutrients and outward diffusion of neurotransmitters. Moreover, the encapsulation procedure may prevent the tumor formation of enclosed cells, when they are derived from tumor cells. In the present study, PC12 cells, a dopaminergic cell line derived from a rat pheochromocytoma, were enclosed within an agarose/poly (styrene sulfonic acid) (agarose/PSSa) mixture and transplanted into the brains of rats (allogeneic transplantation) or guinea pigs (xenogeneic transplantation). Tyrosine hydroxylase (TH) immunoreactive PC12 cells within the microcapsules were observed in all rats and guinea pigs at least up to five weeks after transplantation. PC12 cells were round in shape and of relatively uniform small size. Although PC12 cells occasionally formed cell clusters, the formation of a tumor was not observed. The host reaction to agarose/PSSa microcapsules was minimum. The degree of glial fibrillary acidic protein (GFAP) positive astrocyte density around the microcapsules was similar to that around injection tracks. There was no apparent immunological rejection around the capsules. High-performance liquid chromatography with electrochemical detection (HPLC-EC) showed basal and potassium-evoked release of dopamine from the PC12 cell-enclosed microcapsules in vitro. Although our data is preliminary, we believe that agarose/PSSa microcapsules are promising for producing semipermeable membranes that enable allo-and xenotransplantation of neurosecretory cells into the brain in the absence of systemic immunosuppression. This approach is expected to be applied in Parkinson's disease in the near future.

Adrenal Gland Neoplasms↗