Search PubMed⌕ Search

Biomedical subjects

R Hata

Publications and source records attributed to R Hata.

At least 73 records · Page 4Linked to original sources
PubMed1991

[Clinical study of renal cell carcinoma as incidental finding].

Reports on renal cell carcinoma (RCC) as an incidental finding have been increasing in recent years as the imaging modalities including ultrasonography (US) and computerized tomography (CT) scan have gained popularity in clinical medicine. Because effective treatment in RCC is only surgical removal of the involved kidney even at present, it is imperative for urologists to find and to diagnose the RCC in early stage. Whether RCC found incidentally is in early stage cancer is not determined at present. To determine if the RCC found incidentally is in early stage cancer and if the survival rate is better than that of the RCC found with symptoms, we undertook the following study. Between December 1972 and March 1990, 65 patients with RCC were registered at the Department of Urology, Teikyo University Hospital. Of 65 patients 20 with RCC as an incidental finding were subjected to this study. 34 patients with RCC found with symptoms including hematuria were subjected to control group. Causes of the diagnosis in 20 patients included workup for non-urological diseases in 11 patients (55.0%), workup for urological disease other than RCC in 5 patients (25.0%) and routine medical checkup in 4 patients (20.0%). First-line imaging modalities for the diagnosis was US in 9 patients (45.0%), DIP in 6 patients (30.0%) and CT in 5 patients (25.0%). Size of the tumor, pathological stage (pT) and grade in these 20 patients were tended to be smaller and lower, respectively, but these results were not significant as compared to those of the control group. Incidence of the remote metastasis, at the time of diagnosis, however, was significantly lesser than that of the control group (p = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[A case of systemic lupus erythematosus with the central nervous system manifestations (CNS-lupus) mimicking herpes simplex encephalitis (HSE)].

A 21-year-old male with SLE developed seizure, loss of consciousness and focal signs referable to involvement of the front-temporal brain regions. MRI (magnetic response imaging) image revealed high signal areas in the temporal lobes. By these findings, herpes simplex encephalitis (HSE) was suspected at first. But neither isolation of herpes simplex virus nor HSV specific IgM by ELISA was detected. Acyclovir administration by intravenous infusion was'nt effective but corticosteroid pulse therapy was effective. The level of anticardiolipin antibody was very high. Finally, the diagnosis of CNS-lupus with HSE-like characteristics was made in this case.

Adult↗
PubMed1990

Direct visualization of affected collagen molecules synthesized by cultured fibroblasts from an osteogenesis imperfecta patient.

Human skin fibroblasts obtained from normal controls and a patient with osteogenesis imperfecta were cultured in the presence of ascorbic acid 2-phosphate, a long-acting vitamin C derivative. Crude collagen samples extracted from the cell layer were made to form lateral aggregates of collagen molecules, segment-long-spacing crystallites. Under the electron microscope, normal and abnormal crystallites of type I collagen were identified with the patient's collagen. While the carboxyl-terminal half of the abnormal crystallite was tightly packed, the amino-terminal half was loose and spreading, indicating the site of abnormality in the amino-terminal half of one of type I collagen alpha chains. The method is simple and useful to detect abnormal collagen and to predict the site of mutation.

Adult↗
PubMed1990

'Ischemic tolerance' phenomenon found in the brain.

We investigated the possibility that neuronal cells given a mild ischemic treatment sufficient to perturb the cellular metabolism acquired tolerance to a subsequent, and what would be lethal, ischemic stress in vivo. Cerebral ischemia was produced in the gerbils by occlusion of both common carotids for 5 min, which consistently resulted in delayed neuronal death in the CA1 region of the hippocampus. Minor 2-min ischemia in this model depletes high-energy phosphate compounds and perturbs the protein synthesis, but never causes neuronal necrosis, and therefore was chosen as mild ischemic treatment. Single 2-min ischemia 1 day or 2 days before 5 min ischemia exhibited only partial protective effects against delayed neuronal death. However, two 2-min ischemic treatments at 1 day intervals 2 days before 5 min ischemia exhibited drastically complete protection against neuronal death. The duration and intervals of ischemic treatment, enough to perturb cellular metabolism and cause protein synthesis, were needed respectively, because neither 1-min ischemia nor 2-min ischemia received twice at short intervals exhibited protective effects. This 'ischemic tolerance' phenomenon induced by ischemic stress--which is unquestionably important--and frequent stress in clinical medicine, is intriguing and may open a new approach to investigate the pathophysiology of ischemic neuronal damage.

Animals↗
PubMed1990

Facilitated transport of oxygen through hemoglobin solutions.

A method for quantitative analysis of hemoglobin color to estimate the oxygen saturation was developed. The method uses an image-input and -processing system composed of a 3-tube video camera and a digital image analyzer. When the system is connected to a microscope, the facilitated diffusion of oxygen in hemoglobin solutions can be observed and analyzed in a position-sensitive manner. The results led to a new transport model expressed as: J = k'CY/d, where J is the oxygen flux, C is the hemoglobin concentration, Y is the oxygen saturation of hemoglobin, d is the distance between the entrance of oxygen and the diffusion front, and k' is a constant.

Algorithms↗
PubMed1990

Free radical generation during brief period of cerebral ischemia may trigger delayed neuronal death.

We investigated the pathogenic role of free radical formation in ischemic neuronal death using radical scavenger, superoxide dismutase. Cerebral ischemia was produced in the gerbil by bilateral common carotid occlusion for 5 min, which consistently resulted in delayed neuronal death in the CA1 region of the hippocampus. The effects of free superoxide dismutase and a derivatized superoxide dismutase, pyran copolymer conjugated superoxide dismutase, on early ischemic damages, detected sensitively by the immunohistochemical reaction for microtubule associated protein 2, and a subsequent delayed neuronal death after restoration of blood flow were investigated. Preischemic treatment by pyran conjugated superoxide dismutase showed clear protective effects against both the neuronal damages detected by immunohistochemistry after 5 min ischemia and the delayed neuronal necrosis after one week of recovery, although no clear beneficial effects were observed when this drug was administered just before the recirculation or free superoxide dismutase was used. These results strongly suggest that free radical generation during brief period of ischemia plays a pivotal role in triggering the ischemic neuronal damages causing delayed neuronal death at the selectively vulnerable areas of the brain.

Animals↗
PubMed1990

Age-dependent changes in collagen metabolism and response to hypertonic culture conditions of rat aortic smooth muscle cells and skin fibroblasts.

The rates of growth and collagen synthesis of rat aortic smooth muscle cells in culture were decreased with increasing the age of the animals from which the cells were obtained. These rates were further decreased by the presence of a 0.1 M excess concentration of KCl in the culture medium, and the cells obtained from older animals were much more sensitive to the inhibitory effect of the hypertonic culture condition. These tendencies were observed in smooth muscle cells obtained from different phases of in vitro cellular aging and also in skin fibroblasts obtained from animals of different ages. These results indicate that the cells become more sensitive to the environmental changes with increasing age both in vivo and in vitro.

Aging↗
PubMed1990

Epidermal growth factor regulates gene expression of both epithelial and mesenchymal cells in mouse molar tooth organs in culture.

Epidermal growth factor and cis-hydroxyproline specifically inhibited synthesis of type 1 collagen, a major gene product of the differentiated dental mesenchymal cells (odontoblasts). In tandem, synthesis of enamel proteins, specific gene products of differentiated dental epithelial cells (ameloblasts), was also inhibited. Under these culture conditions, total protein synthesis in tooth organs was not inhibited but rather increased. Inhibition curves of the gene products specific for epithelial and mesenchymal phenotypes were quite similar, indicating coordinate and intimately associated regulation of gene expression under conditions that perturb cytodifferentiation.

Animals↗
PubMed1990

[Functional alterations of human platelets following 111In labeling with different ligands and incubation media].

We studied the effects of various 111In-water soluble chelates and incubation media on labeling efficiency of platelets and in vitro platelet aggregability. High labeling efficiency of platelets in ACD-saline was achieved with 111In-oxine sulfate, 111In-tropolone and 111In-MPO (2-mercaptopyridine-N-oxide). In the condition with 4.8 x 10(6)/mm3 platelets in ACD-plasma, 111In-oxine-sulfate had low labeling efficiency and inconsistent labeling, while 111In-tropolone and 111In-MPO had high labeling efficiency. In vitro platelet aggregability (ADP 2 microM) was reduced when platelets were labeled in the absence of plasma. However, there was no significant difference in platelet aggregability among 111In-platelets labeled by three different chelates. In conclusion, to maintain aggregation activity of the platelets with relatively high labeling efficiency, the best result was obtained by using MPO or tropolone chelate in plasma at 4.8 x 10(6)/microliters platelet concentration.

Adult↗
PubMed1989

L-ascorbic acid 2-phosphate stimulates collagen accumulation, cell proliferation, and formation of a three-dimensional tissuelike substance by skin fibroblasts.

Proliferation of human skin fibroblasts was stimulated significantly by the presence of L-ascorbic acid 2-phosphate (Asc 2-P). The presence of Asc 2-P (0.1-1.0 mM) in the culture medium for 3 weeks enhanced the relative rate of collagen synthesis to total protein synthesis 2-fold as well as cell growth 4-fold. Coexistence of L-azetidine 2-carboxylic acid (AzC), an inhibitor of collagen synthesis, attenuated both effects of Asc 2-P in a dose-dependent manner. Supplementation of the medium with Asc 2-P also accelerated procollagen processing to collagen and deposition of collagen in the cell layer. Among the acidic glycosaminoglycans (GAG), another major component of extracellular matrix (ECM), deposition of sulfated forms was increased by the additive. Electron microscopic observations showed multilayered, rough endoplasmic reticulum-rich cells surrounded by dense ECM. These results indicate that Asc 2-P is useful in culture systems as a long-acting vitamin C derivative and also that it promotes reorganization of a three-dimensional tissuelike substance from skin fibroblasts in culture by stimulating collagen accumulation in the fibroblasts.

Ascorbic Acid↗
PubMed1989

Microtubule-associated protein 2 as a sensitive marker for cerebral ischemic damage--immunohistochemical investigation of dendritic damage.

We investigated the neuronal distribution of microtubule-associated protein 2 in gerbil brain and monitored the progression of ischemic damage immunohistochemically by using this protein as a dendritic marker. The reaction for microtubule-associated protein 2 in normal gerbil brain clearly visualized neuronal soma and dendrites but other structures such as axonal bundles, glia and endothelial cells exhibited little immunoreactivity. In a reproducible gerbil model of unilateral cerebral ischemia, we could detect the ischemic lesions as early as 3 min after right common carotid occlusion at the subiculum-CA1 region of the ipsilateral hippocampus as faint loss of the reaction in the dendrites. After ischemia for 30 min, the ischemic lesions were clearly detected as loss of the reaction in the nerve cell bodies, dendrites and the neuropil in the hippocampus, cerebral cortex, thalamus and the caudoputamen. Although the mechanism for prompt disappearance of the immunohistochemical reaction for microtubule-associated protein 2 is not clear, the present investigation suggests that dendrites in the vulnerable regions may be quite susceptible to ischemic stress and that the immunohistochemical procedure for microtubule-associated protein 2 may be very useful for demonstration of dendritic damage in various pathophysiological states of the central nervous system.

Animals↗
PubMed1989

Co-culture of fibroblasts and hepatic parenchymal cells induces metabolic changes and formation of a three-dimensional structure.

Co-culturing of tendon fibroblasts and liver parenchymal cells in Williams' medium E supplemented with fetal bovine serum, hormones, and L-ascorbic acid 2-phosphate, a long acting vitamin C derivative, resulted in formation of three-dimensional structure. Both growth of fibroblasts and their production of collagen were inhibited, however production of albumin by the hepatocytes was much better preserved than when individual cells were cultured separately, indicating epithelial-mesenchymal interactions stimulate reorganization of the liver-like tissue from isolated cells.

Achilles Tendon↗
PubMed1989

[Clinical study of inpatients with urolithiasis during the past 10 years].

The 348 patients with urolithiasis admitted to our department between 1978 and 1987 were studied clinically. Male patients were predominant over females with the male-to-female ratio being 2 to 1. Of 404 uroliths, 389 (96.3%) were upper urinary tract stones, and 15 (3.7%) were lower urinary tract stones. Two hundred and sixty patients (74.7%) had a solitary stone, and 71 patients (20.4%) multiple stones. There were fewer patients with recurrent stones (42 patients, 12.1%) than non-recurrent stone formers. Methods of stone removal were variable including open and endourologic surgeries. The most frequent type of removal of stone was catheter extraction (92 patients, 39.8%). Percutaneous nephrolithotripsy (PNL) and transurethral ureterolithotripsy (TUL) were done on 6 (2.6%) and 5 (2.2%) patients, respectively. Extracorporeal shock wave lithotripsy (ESWL) was not done at this hospital during this period. Spontaneous passage of stone was seen in 70 patients: stones in 38 passed after catheterization. Rate of spontaneous passage of stone in untreated group was 33.5%. Calcium-containing urinary stone was the most frequent type of stone according to analysis of 56 stones with the infrared spectrometry. In conclusion, 1) etiology of urinary tract stone in all recurrent stone formers and in all patients with multiple stones must be pursued, and 2) all stones either removed or passed must be subjected to infrared spectrometry. ESWL, TUL and PNL are expected to be the main modes of stone removal instead of open surgery and conventional catheter extractions in the near future.

Adolescent↗
PubMed1989

[A case of primary bilateral epididymal leiomyoma].

Primary epididymal tumors are relatively rare entity. Leiomyoma is the second most common benign epididymal tumor. Recently, we experienced a case of primary bilateral epididymal leiomyoma. A 50-year-old man presented with painless masses in both epididymal tails several years in duration. Solid tumors of both epididymal tails with undetermined characteristics were diagnosed. At surgery both masses were solid and smooth and were found to be well-demarcated. They were removed without difficulty. Pathology was bilateral epididymal leiomyoma. We also reviewed 55 cases of epididymal leiomyoma in the Japanese literature.

Epididymis↗
PubMed1988

Existence of malfunctioning pro alpha2(I) collagen genes in a patient with a pro alpha 2(I)-chain-defective variant of Ehlers-Danlos syndrome.

Collagen synthesis was examined in skin fibroblasts from a patient with a variant of Ehlers-Danlos syndrome. The relative rate of collagen synthesis to total protein synthesis in the patient's fibroblasts was always one-half of that in fibroblasts from normal controls. Total collagen synthesis, as assessed by quantification of total hydroxyproline, was also significantly lower than that of controls, indicating that the rate of collagen synthesis by the patient's fibroblasts was decreased compared with that by normal fibroblasts. Analysis of procollagen and collagen components showed the absence of the pro alpha 2(I) chain and its derivatives. Dot-blot and Northern-blot analyses showed the patient's fibroblasts to contain less than 10% of the mRNAs for pro alpha 2(I) found in control fibroblasts. In spite of these results, Southern blot analysis of genomic DNA indicated the presence of the same number of genes for the pro alpha 2(I) collagen chain in the patient's fibroblasts as in control fibroblasts, suggesting malfunctioning pro alpha 2(I) collagen genes as the cause for failure of the patient's fibroblasts to synthesize pro alpha 2(I) collagen chains.

Adult↗
PubMed1988

Regulation of collagen metabolism and cell growth by epidermal growth factor and ascorbate in cultured human skin fibroblasts.

Epidermal growth factor (2-50 ng/ml), prepared from mouse submaxillary glands, stimulated growth and the synthesis of non-collagenous proteins and hyaluronic acid, but inhibited collagen synthesis in cultured human skin fibroblasts, both stimulation and inhibition being dose-dependent. All these effects may be intrinsic functions of the epidermal growth factor molecule, because these effects were cancelled by the co-presence of antiserum specific for epidermal growth factor and because they were also observed following the addition of human epidermal growth factor produced urogastrone cDNA. On the other hand, L-ascorbate (vitamin C) stimulated growth and collagen synthesis, as well as synthesis of non-collagenous proteins, with no significant effect on hyaluronic acid synthesis. Co-presence of epidermal growth factor and ascorbate gave additive effects on growth and protein synthesis of the cells. These results suggest that the two growth-promoting factors, epidermal growth factor and L-ascorbate, modulate metabolism of extracellular matrix components as well as cell growth in a quite different manner in human skin fibroblasts.

Adult↗
PubMed1988

Color analysis method for studying oxygen transport in hemoglobin solutions using an image-input and -processing system.

A method for quantitative analysis of hemoglobin color to estimate the oxygen saturation was developed. The method uses an image-input and -processing system composed of a 3-tube video camera and a digital image analyzer. Using the system connected to a microscope, facilitated diffusion of oxygen in hemoglobin solutions was observed and analyzed in a position-sensitive way. The results confirmed its applicability to this study and gave information about the diffusion mechanism expressed by the empirical formula J = kY, where J is the flux of oxygen, Y is the oxygen saturation of hemoglobin, and k is a constant.

Colorimetry↗