Biomedical subjects

K Uchida

Publications and source records attributed to K Uchida.

At least 631 records · Page 35Linked to original sources

PubMed1996

Clinical evaluation of irreversible data compression for computed radiography in excretory urography.

Efficient data compression is required for practical daily use of digital images in computed radiography (CR). This study investigated the clinical utility of data compression in excretory urography using the FCR 9000 system (Fuji Photo Film, Tokyo, Japan). Type III data compression technique was used, which can achieve a 20:1 to 25:1 compression ratio. To evaluate the degradation of image quality, we compared paired original and compressed CR images. Although a slight deterioration of image quality was noted in the renal calyx including collecting tubules among various anatomical structures, the difference was not significant. Receiver operating characteristics analysis revealed no significant difference among the original and compressed images. We conclude that compressed CR images using Type III data compression technique in excretory urography appear to be clinically applicable and acceptable.

Adolescent↗

PubMed1996

Lumbosacral dumb-bell neurilemmoma approached by microsurgical interlaminar foraminotomy. A case report.

The case history of a patient with a dumb-bell neurilemmoma arising from the L5 nerve root is described. The tumour extended into the outlet of the neural foramen at L5-S1 on the left and was also compressing the dural sac and the S1 nerve root. A limited laminotomy at L4-5 and L5-S1, with preservation of the neural arch, was followed by microsurgical medial foraminotomy at L5-S1 which allowed visualisation of the nerve root and enucleation of the tumour. The technique maintains stability of the posterior elements and spinal movement, and is recommended for the removal of this type of tumour.

Adult↗

PubMed1996

Clonal analysis of nodular parathyroid hyperplasia in renal hyperparathyroidism.

Although it is well known that chronic renal failure induces parathyroid hyperplasia, the pathogenesis and development of this parathyroid lesion in this disease are poorly understood. Histopathologically, there is progression from diffuse to nodular hyperplasia, and each nodule consists of a single cell type with aggressive proliferative potential. Pathophysiologic and clinical investigations have suggested that neoplastic tumors may emerge from nodular hyperplasia. In this study the clonality of parathyroid tissue in nodular and diffuse hyperplasia in renal hyperparathyroidism was analyzed by a method based on restriction fragment length polymorphism of the X chromosome-linked phosphoglycerokinase gene and on random inactivation of the gene by methylation. DNA of peripheral lymphocytes was screened in 43 women undergoing parathyroidectomy for advanced renal hyperparathyroidism, and 10 of these patients appeared to be heterozygous. Fourteen specimens from these patients were available for clonal analysis. The analysis showed that all four specimens of diffuse hyperplasia were polyclonal, whereas all seven specimens from nodules in nodular hyperplasia and all three samples representing parathyroid tissue removed from forearm because of graft-dependent recurrence were revealed to be monoclonal. It is likely that the clonal origin of each nodule is independent. These results suggest that in renal hyperparathyroidism parathyroid glands initially grow diffusely and polyclonally, and then the cells in the nodules are later transformed monoclonally and proliferate aggressively. From the present study it can be concluded that nodular hyperplasia represents monoclonal parathyroid neoplasia, which might explain why patients with nodular hyperplasia in renal hyperparathyroidism are refractory to medical treatment, requiring parathyroidectomy. To prevent recurrences, nodular hyperplastic tissue should not be left at surgery.

Adult↗

PubMed1996

Exclusion of Sox9 as a candidate for the mouse mutant tail-short.

The Sry-related gene Sox9 has been proposed as the gene responsible for the mouse skeletal mutant Tail-short (Ts), on the basis of its expression in skeletogenic mesenchymal condensations in the mouse embryo and its chromosomal location in the region of Ts on distal Chromosome (Chr) 11. We present here detailed mapping of Ts locus relative to the Sox9, using an intersubspecific cross. Among 521 backcross progeny, 16 recombinants were detected between Sox9 and Ts, suggesting a separation of 3.5 +/- 0.01 cM, and excluding Sox9 as a candidate for Ts. A further nine recombinants were detected between Ts and the polycomb-like gene M33, suggesting that these loci are separated by 1.8 +/- 0.011 cM. Six microsatellite markers were co-localized to the Ts locus, providing reagents for positional cloning of Ts.

Animals↗

PubMed1996

Senile plaques in very aged cats.

Senile plaques were found in the cerebral cortices of three very aged cats (more than 18 years old). The plaques consisted of a coarse assembly of silver staining-positive materials, and was morphologically different from the well-known classical, primitive, and diffuse plaques. Congophilic amyloid angiopathy was observed in a few cortical arterioles of the oldest cat (20 years old). The senile plaques and a few cortical blood vessels were immunopositive for amyloid beta-protein (A beta). A beta-positive materials were also sparsely distributed in the cortical neuropil but did not form senile plaques there. These findings should help to clarify the development of senile plaques and the early stage of A beta deposition.

Aging↗

PubMed1996

Expression of platelet-derived growth factor B-chain in neointimal smooth muscle cells of balloon injured rabbit femoral arteries.

In order to obtain information about the developmental mechanisms of restenosis after angioplasty, we investigated an association between the expression of platelet-derived growth factors (PDGFs) and neointimal cell accumulation in rabbit femoral arteries subjected to balloon angioplasty. Northern analysis demonstrated that mRNA expression of PDGF B-chain (PDGF-B) increased markedly in the injured arteries, peaking at day 7 (sevenfold), and the transcripts remained augmented until day 21. Also transcripts of PDGF beta-receptor (PDGFR-beta) and alpha-receptor increased by 3- and 2.5-fold, respectively, but those of PDGF A-chain showed only a slight increase (1.5-fold). In situ hybridization and immunohistochemistry demonstrated the concordant expression of mRNA and protein for PDGF-B in the smooth muscle cells (SMCs) of injured vessels throughout the experiment. PDGF-B expression peaked in neointimal SMCs at day 7. In accordance with PDGF-B expression, cellular proliferation in neointima peaked at day 7, being followed by a dramatic increase of neointimal areas thereafter. Further, we demonstrated PDGFR-beta immunoreactivity in these neointimal cells with PDGF-B expression. Our data provide evidence that PDGF-B may stimulate vascular SMC proliferation and contribute to neointimal formation after angioplasty.

Angioplasty, Balloon↗

PubMed1996

Corneal endothelial changes in schizophrenic patients with long-term administration of major tranquilizers.

PURPOSE: To examine corneal endothelial changes in schizophrenic patients who underwent long-term administration of major tranquilizers. METHODS: We performed slit-lamp examination and endothelial specular microscopy on 100 eyes of 50 schizophrenic patients (range, 31 to 68 years old; mean, 54 years) who underwent long-term (12 to 44 years) treatment with major tranquilizers. We also studied 50 eyes of 25 patients (range, 31 to 65 years old; mean, 53 years) with no history of corneal disease, as a control group of similar age. Mean cell density, coefficient of variation, and percentage of hexagonal cells were calculated and statistically compared between patients and controls using an unpaired t-test. RESULTS: Slit-lamp examination disclosed pigmentation of the cornea in nine eyes of five patients and pigmentation of the lens in 25 eyes (25%) of 35 patients. Corneal pigmentary changes were seen only in patients with lenticular changes. No eyes showed corneal edema. In contrast, no corneal abnormalities were seen in any control eye. Specular microscopic analysis showed mean cell density of 3,484.4 +/- 462.6 cells/mm2, coefficient of variation of 0.31 +/- 0.06 and percentage of hexagonal cells to be 60.2% +/- 7.5% in the patient group, and 3,291.3 +/- 384.4 cells/mm2, 0.32 +/- 0.07, and 60.6% +/- 7.0%, respectively, in the control subjects. There were no statistically significant differences between patient and control eyes in these three factors. The nine eyes with corneal pigmentation showed no significant differences in these three factors as compared with the control subjects. CONCLUSIONS: These results indicate that long-term treatment with major tranquilizers is not associated with morphometric abnormalities of the corneal endothelium.

Adult↗

PubMed1996

Outcome of radical surgery for carcinoma of the gallbladder according to the TNM stage.

BACKGROUND: The role of surgery in the treatment of gallbladder carcinoma (GBC) is controversial. The outcome after prospective radical surgery for GBC is discussed on the basis of the TNM stage of the tumor. METHODS: One hundred six patients who had undergone radical surgery were selected. The standard radical procedure consisted of a cholecystectomy accompanied by lymph node dissection, wedge resection of the liver, and resection of the extrahepatic bile ducts. The stage was determined by pathologic examination of resected specimens. RESULTS: Lymph node metastases were identified in no patients with T1 tumors (n = 15), 48% of patients with T2 tumors (n = 46), 72% of patients with T3 tumors (n = 25), and 80% of patients with T4 tumors (n = 20). One patient died within 30 days after radical surgery (mortality rate, 0.9%). There were 35 5-year survivors including 11 patients with nodal involvement, 10 with stage I tumors, 13 with stage II tumors, 10 with stage III tumors, and 2 with stage IV tumors. The cumulative 5-year survival rate in patients with stage I tumors was 91% (n = 15), 85% in patients with stage II tumors (n = 24), 40% in patients with stage III tumors (n = 28), and 19% in patients with stage IV tumors (n = 39). In patients with stage III and IV tumors the 5-year survival rate was 52% after curative resection (n = 35). This was significantly better than the 5% 5-year survival rate after a noncurative resection (n = 32). CONCLUSIONS: The presence of lymph node metastases is strongly influenced by the depth of invasion of the primary tumor. Accurate determination of the TNM stage is essential in comparing surgical results, predicting patient outcome, and planning additional treatment. Standard radical surgery contributes to patient survival and is recommended in patients with advanced GBC.

Adult↗

PubMed1996

Pathogenic role of thromboxane A2 in immediate food hypersensitivity reactions in children.

BACKGROUND: Food hypersensitivity, from the standpoint of pathogenesis as well as clinical management, remains controversial. During the food allergen-induced immediate hypersensitivity reaction, various chemical mediators are released. OBJECTIVE: The purpose of our study was to determine whether thromboxane A2 participates in food antigen-induced responses in children with food hypersensitivity. METHODS: Nine open food challenges were performed in nine patients with suspected food hypersensitivity. Plasma thromboxane B2 and histamine levels were measured during a 24-hour period following the challenge. RESULTS: All the patients demonstrated immediate reactions after food challenge. The mean plasma thromboxane B2 level (a marker of thromboxane A2 activity) rose significantly at two hours and three hours after the challenge. Simultaneously, the mean plasma histamine level rose significantly at two hours and three hours after the challenge. CONCLUSIONS: The results suggest that thromboxane A2 may play a pathogenic role in part in the immediate reaction after food challenge and that thromboxane A2 is probably released from a common cellular source (eg, mast cell) with histamine and/or by a common mechanism (eg, IgE-dependent platelet activation).

Child↗

PubMed1996

Microsurgical nerve root canal widening without fusion for lumbosacral intervertebral foraminal stenosis: technical notes and early results.

We describe a technique for microsurgical widening of the nerve root canal in the lumbosacral spine. We also report our early results in 31 patients (19 men and 12 women; average follow-up, 3.2 years) with such foraminal stenosis but without osseous defects in the pars interarticularis and/or spondylolisthesis. The affected nerve root was decompressed by interlaminar medial foraminotomy followed by lateral laminotomy and foraminotomy using a microsurgical technique. The procedure aimed at preserving bony continuity of the pars interarticularis and segmental motion. Neurological results showed a favourable improvement of radicular symptoms and of intermittent claudication. The need for segmental fusion at the operated segment was excluded in 30 patients, but one patient subsequently required a transpedicular screw procedure with bone grafting. We recommend the present technique for effective decompression of the nerve root within the neural foramen, simultaneously maintaining lumbar spine mobile function.

Action Potentials↗

PubMed1996

Development of hydrocephalus after cervical laminoplasty for ossification of the posterior longitudinal ligament: case report.

We report a 69-year-old woman who developed serious hydrocephalus after cervical laminoplasty for ossification of the posterior longitudinal ligament. The patient presented with approximately 50% spinal canal compromise pertaining to ossified lesion at C5 and C6 levels and subsequently underwent a C3-C7 open-door laminoplasty, followed by uneventful neurological recovery until 2 weeks postoperatively. Despite a favourable postoperative course, she presented with serious symptoms and signs of intracranial hypertension about 3 weeks after surgery. Computed tomography demonstrated the appearance of marked hydrocephalus, with no explainable cause. A ventriculoperitoneal shunt followed by removal of subdural fluid in the suboccipital fossa resulted in resolution of the clinical symptoms and of the hydrocephalus. It is important to be aware of the very rare occurrence of such intracranial neurological compromise after a cervical laminoplasty operation for long-standing ossification of the posterior longitudinal ligament.

Aged↗

PubMed1996

Posterior limbus vertebral lesions causing lumbosacral radiculopathy and the cauda equina syndrome.

This report reviews our experience with spinal decompression for posterior limbus vertebral lesions or osteocartilaginous vertebral corner defects in the lumbar spine in 29 children and young adults. There were 19 male and 10 female patients with a mean age of 16.5 years (range, 9 to 24 years). Twenty-four patients were involved with various athletic activities. Clinical presentation included low back pain with a variable degree of radiculopathy in 25 patients and a cauda equina syndrome in four. The level of the affected spinal area was L1-2 in one patient, L2-3 in one, L3-4 in seven, L4-5 in 17, and L5-S1 in three. The preoperative imaging workup showed lateralised "non-calcified' or 'calcified' limbus vertebral defects in 13 patients and centrally displaced lesions in 16 patients. All patients underwent posterior spinal decompression with a slightly extended laminotomy, except for three patients who had a subsequent posterolateral fusion. All of the patients consequently returned to practice their favourite preoperative sport and lifestyle, but five discontinued their previous sports. We suggest that patients with posterior limbus vertebral lesions require careful diagnosis and therapy that are different from those with an ordinary lumbar disc herniation.

Adolescent↗

PubMed1996

The in-vitro activity of an antifungal antibiotic benanomicin A in comparison with amphotericin B.

Benanomicin A showed a broad antifungal spectrum, inhibiting the growth of all test strains of 41 yeasts, 23 dimorphic fungi, 23 dematiaceous fungi, 16 aspergilli, and 19 dermatophytes, with the exception of 12 zygomycetic strains. The MIC values of benanomicin A were comparable to those of amphotericin B against Cryptococcus. Rhodotorula, Trichosporon, Geotrichum, Sporothrix, and some dermatophytes, but were two to eightfold higher than those of amphotericin B against other fungal pathogens tested. The action of benanomicin A was fungicidal.

Amphotericin B↗

PubMed1996

Cloning and expression of an isovaleryl pepstatin-insensitive carboxyl proteinase gene from Xanthomonas sp. T-22.

Xanthomonas carboxyl proteinase (XCP), isolated from Xanthomonas sp. T-22, is the second example of the unique carboxyl proteinases [EC 3.4.23.33] which are insensitive to the classical aspartic proteinase inhibitor. The gene coding for XCP was cloned, sequenced, and expressed in Escherichia coli. The XCP gene contains an open reading frame of 2,481 base pairs encoding a protein of 827 amino acid residues with a M(r) of 83,677. The XCP was synthesized as a large precursor consisting of three regions: NH2-terminal prepro (N-Prepro) (237 amino acid residues); mature XCP (398 a.a.residues); and COOH-terminal pro (C-Pro) (192 a.a. residues). The N-Prepro and mature XCP regions had no sequence similarity to any other proteins reported so far, except the carboxyl proteinase from Pseudomonas sp. 101 [Oda, K., Takahashi, T., Tokuda, Y., Shibano, Y., and Takahashi, S. (1994) J. Biol. Chem. 269, 26518-26524]. The C-Pro region showed high similarity to COOH-terminal regions of other microbial proteinase precursors. E. coli carrying a plasmid containing the cloned wild-type XCP gene produced an 84-kDa protein. This protein was processed into a mature, active form under acidic conditions. This process was completely blocked by tyrostatin, an XCP-specific inhibitor from Kitasatosporia sp. 55, indicating an autocatalytic processing. The purified recombinant XCP had the same characteristics as authentic XCP except for the NH2-terminal amino acid sequence. When the mutant XCP gene truncated in the C-Pro region was expressed in E. coli, an expected 64-kDa protein was detected in the cells, and also processed into the 42-kDa active form under the acidic conditions. Thus, the C-Pro region was not essential for the formation of active mature XCP.

Amino Acid Sequence↗

PubMed1996

Mutation analysis of gonadotropin receptor and G protein genes in various types of human ovarian tumors.

The heterotrimeric guanine-nucleotide-binding proteins (G proteins) and G protein-coupled hormone receptors including gonadotropin receptors have been suggested to play a role in ovarian tumorigenesis. However, no functional significance of gonadotropin receptors and G proteins in this process has been demonstrated. To investigate this issue, we examined point mutations in these genes in various types of ovarian tumors by polymerase chain reaction-single strand conformation polymorphism analysis and direct sequencing. Among 37 tumors (20 epitherial, 8 sex cord-stromal, and 9 germ cell tumors) and 5 carcinoma cell lines examined, no mutational sequence of G protein-interaction domains of luteinizing hormone receptor and follicle-stimulating hormone receptor, or "hot spots" of the alpha subunit of adenylyl cyclase-stimulating G protein and -inhibitory G protein was observed. Although this analysis was performed on only a limited number of tumors and cell lines, and on limited gene loci, the results suggest that mutational activation in gonadotropin receptors and G proteins is not crucial for ovarian tumorigenesis.

Female↗

PubMed1996

Isolation and characterization of the cDNA for an A-like cyclin in Adiantum capillus-veneris L.

We have isolated and characterized the cDNA for a homolog of a cyclin from the fern Adiantum capillus-veneris L. Three fragments of cDNAs for cyclin homologs were amplified by the PCR from the cDNA of germinating spores with degenerate primers that encoded the highly conserved region in the so-called cyclin box. We isolated a full-length cDNA for cyclin from a lambda ZAPII-cDNA library that has been derived from spores using an amplified fragment as a probe. The cDNA insert (Cyc-Ac1) in one positive clone was 2.0 kb in length, having an open reading frame of 1,599 bp that encoded 532 amino acids. The putative CycAc1 protein had a cyclin box and a destruction motif, and it was homologous to A-type cyclins. Northern blot analysis was performed to study the expression of CycAc1 during the first cell cycle in the haploid generation of the fern. CycAc1 mRNA was not detectable in dormant spores, during the first G1 phase, and at the onset of the S phase in imbibed spores after breaking of dormancy. This mRNA became detectable after the termination of the S phase, and it accumulated during the second G1 phase. Although CycAc1 was classified as an A-like cyclin, the failure to detect CycAc1 mRNA at the onset of the S phase suggests that CycAc1 might not play a role in the replication of DNA during the S phase.

Amino Acid Sequence↗

PubMed1996

Painless thyroiditis occurring during long-term treatment with interferon alfa in a patient with chronic active hepatitis C.

We describe here painless thyroiditis during interferon (IFN) therapy in a 65-year-old man with chronic active hepatitis C. The patient had hypothyroidism in the late stage of a 24-week course of treatment with IFN-alpha. After cessation of the treatment a small, firm goiter was noticed, and chronic focal thyroiditis was diagnosed histologically. Analyses of the stock serum samples drawn before, during, and after IFN-alpha therapy revealed transient hyperthyroidism followed by transient hypothyroid states with aggravation of antithyroid hormone antibody titers. These findings suggest that long-term IFN-alpha therapy caused painless thyroiditis with aggravation of autoimmunity in our patient with preexisting chronic thyroiditis.

Aged↗

PubMed1996

8-hydroxy-2'-deoxyguanosine is increased in epidermal cells of hairless mice after chronic ultraviolet B exposure.

8-Hydroxy-2'-deoxyguanosine (8-OHdG) is a mutation-prone (G:C to T:A transversion) DNA base-modified product generated by reactive oxygen species or photodynamic action. G:C to T:A transversions are observed in the p53 and ras genes of UVB-induced skin cancers of mice and in squamous and basal cell carcinomas of human skin exposed to sunlight. In the current study, 8-OHdG formation was evaluated in the epidermis of hairless mice after repeated exposure to UVB, and possible mechanisms involved were studied. Exposure of hairless mice to either 3.4 [2 minimal erythema dose (MED)] or 16.8 (10 MED) kJ/m2 of UVB three times a week for 2 wk induced a 2.5- or 6.1-fold increase, respectively, in the levels of 8-OHdG in DNA, compared to the unexposed controls. An immunohistochemical method using a monoclonal antibody specific for 8-OHdG showed stronger and more extensive staining in the nuclei of UV-irradiated epidermal cells than in those of nonirradiated cells. Western blots probed with antibodies against 4-hydroxy-2-nonenal-modified proteins confirmed the involvement of reactive oxygen species in the epidermal damage induced by chronic UVB exposure. 3-Nitro-L-tyrosine was detected in western blots in a concentration-dependent manner, suggesting that peroxynitrite derived from the reaction of nitric oxide and superoxide, both of which were probably released from inflammatory cells, was involved in modifying the DNA bases. Therefore, the formation of 8-OHdG after UVB exposure appears to be regulated by at least three pathways: photodynamic action, lipid peroxidation, and inflammation and may play a role in sunlight-induced skin carcinogenesis.

8-Hydroxy-2'-Deoxyguanosine↗