Biomedical subjects

K Ishida

Publications and source records attributed to K Ishida.

At least 199 records · Page 11Linked to original sources

PubMed1998

MR imaging of the central nervous system in divers.

BACKGROUND: Magnetic resonanse imaging (MRI) frequently reveals asymptomatic cerebral infarctions in the general population. HYPOTHESIS: The central nervous system (CNS) of divers is affected by a hyperbaric environment even if they are asymptomatic. METHODS: We examined 25 uniformed service divers by MRI and compared them with normal controls. RESULTS: Of 25 divers, 9 had CNS lesions vs. 2 of 25 controls (p = 0.02). There was a significant relationship between the CNS lesions, age, and smoking. CONCLUSION: The divers had a risk of accumulating CNS lesions. These results suggested that divers should undergo periodic medical evaluations and MRI brain scanning.

Adult↗

PubMed1998

Distinction of the shape of Helicobacter pylori using stereo pairs constructed from digitized light microscopic images.

This study was performed to distinguish between the coccoid form or spiral forms of Helicobacter pylori (Hp) and to elucidate the pathologic significance of these shapes of Hp. Specimens obtained from human or Mongolian gerbil stomachs were fixed in Carnoy's solution and embedded in paraffin. Sections 3 or 10 microm thick were stained with polyclonal anti-Hp antibody by the immunoperoxidase method. Stereo pairs were prepared from these thick sections by computer-assisted reconstruction. The two shapes of Hp were easily distinguishable by this method. In the human stomach, the proportions of Hp in the surface mucous gel layer (SMGL) and the gastric pits were 31.5% and 68.5%, and the percentage of the spiral form varied from 31.9% to 66.3%. In Mongolian gerbils, a higher proportion of Hp colonized the SMGL, and the spiral form existed more frequently both in the SMGL and on the surfaces of the surface mucous cells.

Animals↗

PubMed1998

Extracellular matrix production regulation by TGF-beta in corneal endothelial cells.

PURPOSE: Production of extracellular matrix (ECM) by corneal endothelial cells is related to physiologic functions and pathologic conditions and is regulated by many cytokines, including transforming growth factor-beta (TGF-beta). In this study, the molecular mechanism of ECM production regulation by TGF-beta was investigated in cultured corneal endothelial cells. METHODS: The production of ECM components (laminin and fibronectin) was detected in cultured corneal endothelial cells by western blot analysis. To determine the signal transduction pathways, mutant TGF-beta type I receptor (TbetaR-I) and/or Smad protein family members (intracellular signal transducers in TGF-beta signaling) were overexpressed by transfecting their cDNA into the cultured cells, and the effects on ECM production were observed. RESULTS: The production of laminin and fibronectin was stimulated by treatment with TGF-beta1 or TGF-beta2. After transient transfection of cDNA of the constitutively active (CA) mutant of TbetaR-I, the production of laminin and fibronectin was stimulated even in the absence of TGF-beta. The transfection of the dominant negative mutant of TbetaR-I counteracted the effects of TGF-beta. These results confirm that TGF-beta directly stimulates ECM production from corneal endothelial cells through TbetaR-I. The ECM production stimulation by TGF-beta or CA TbetaR-I was accelerated by the overexpression of Smad2, Smad3, and/or Smad4 and inhibited by that of Smad7. These results show that TGF-beta signals connected to ECM production are regulated by Smad family members, located downstream of TbetaR-I. CONCLUSIONS: The results of this study show that TGF-beta stimulates ECM production from corneal endothelial cells through TbetaR-I and Smad family transducers.

Animals↗

PubMed1998

Antitumor glycogen from scallops and the interrelationship of structure and antitumor activity.

Hot water extract of scallop was treated with actinase E and fractionated by Sephadex G-25 gel-filtration and DEAE Sephadex A-25 ion-exchange chromatography. The antitumor activity of these fractions against Meth-A fibrosarcoma was examined. The nonadsorbed fraction (SCA25A) and weakly adsorbed fraction (SCA25B) obtained on DEAE Sephadex A-25 anion-exchange gel showed strong antitumor activity. Chemical analyses and NMR spectra identified SCA25A and SCA25B as glycogen. However, glycogen extracted from the scallop with trichloroacetic acid and from abalone showed no antitumor activity. This difference was thought to be due to variations in the fine structure of the glycogen molecule. The fine structure of glycogen was investigated by a sequential enzyme digestion method using beta-amylase and pullulanase, while the unit chain was analyzed by high performance anion exchange chromatography. The results showed that the antitumor active glycogen was highly branched with a shorter chain than glycogens without antitumor activity.

Journal Article↗

PubMed1998

Clinical factors associated with progression of normal-tension glaucoma.

PURPOSE: To investigate clinical factors associated with the progression of visual field loss in normal-tension glaucoma (NTG). METHODS: One hundred and ten patients with NTG whose cases were followed for more than 2 years were retrospectively analyzed with the Kaplan-Meier life table method and the Cox proportional hazards model. Several clinical factors were investigated to find a possible association with progression of glaucomatous visual field defined by two different definitions: one by mean deviation change and the other by pointwise comparison. RESULTS: The Cox proportional hazards model indicated that change in the visual field was significantly associated with treatment with calcium channel blockers, recovery rate from a cold recovery test, systolic blood pressure, disc hemorrhage, corrected pattern standard deviation, mean deviation, and fluctuation of intraocular pressure (IOP) at a 24-hour phasing. The probability of nonprogression of visual field loss was significantly higher for patients taking calcium channel blockers than for control subjects by either definition of visual field progression. CONCLUSION: Factors other than IOP, including the use of calcium channel blockers, are associated with the outcome of visual field loss in NTG.

Adult↗

PubMed1998

Diagnostic value of cervical somatosensory evoked potentials recorded from the intervertebral discs after median and ulnar nerve stimulation in cervical spondylotic myelopathy.

We have studied the cervical somatosensory evoked potentials (CSEPs) recorded referentially from serial intervertebral discs after stimulation of the median nerve or the ulnar nerve at the wrist in cervical spondylosis. In seven unilateral radiculopathies, the CSEPs evoked by stimulation on the asymptomatic side normally consisted of the P1-N1 and the P2-N2 components, which represented the potentials arising from the white matter and the gray matter, respectively. Of 21 myelopathies, the CSEPs revealed the white matter involvement with conduction block identified by abrupt P1-N1 amplitude reduction in 7, the gray matter involvement identified by P2-N2 amplitude reduction in 3, or a combination of both in 11. The CSEPs were useful not only for determining the level responsible for myelopathy but also for localizing the lesion in the transverse plane of the spinal cord.

Adult↗

PubMed1998

Canal-down tympanoplasty; one-stage tympanoplasty with mastoid obliteration, for non-cholesteatomatous chronic otitis media associated with osteitis.

We operated on 54 ears using the canal-down procedure consisting of one-stage tympanoplasty with mastoid obliteration for non-cholesteatoma otitis media with lesions in the ossicular chain and compared the results with those of patients treated with the canal-up procedure. Complications, such as mastoid problems, which have been observed in surgery with the simple canal-down procedure, were not observed in operations combining mastoid obliteration. The success rate for our procedure as evaluated by postoperative hearing levels, according to the standards established by the Japan Society of Clinical Otology, Committee on Nomenclature 1987, was 77.4% with tympanoplasty (ceramic P type) with reconstruction of the ossicular chain; 70.6% with reconstructive surgery using T type ceramic; and 50.0% with reconstructive surgery using the patient's own bone. Overall, the success rate was 72.2%. Our procedure seems to be superior to the canal-up procedure with respect to improvement of hearing levels in the treatment of patients with chronic otitis media associated with lesions in the ossicular chain.

Cholesteatoma, Middle Ear↗

PubMed1997

Identification and characterization of an anti-glial fibrillary acidic protein antibody with a unique specificity in a demented patient with an autoimmune disorder.

We detected an antibody to a 48 kd antigen of the central nervous system in the serum from a demented patient with an autoimmune disorder. To identify and characterize the antigen, we screened a human cerebral cDNA library and performed immunoblot analysis following two-dimensional gel electrophoresis (2-D blotting). The sequences of the isolated cDNA fragments were homologous to human glial fibrillary acidic protein (GFAP). Two-D blotting using patient serum revealed that the antibody reacted with a restricted subset of GFAP molecules which exhibited relatively high isoelectric points. Furthermore, to elucidate the importance of the anti-GFAP antibody in dementia, we screened for the presence of an anti-GFAP antibody in the sera of 46 demented patients: 26 with Alzheimer's disease and 20 with vascular dementia (VD). We found an anti-GFAP antibody in the serum of only one patient with VD. Two-D blotting revealed that the anti-GFAP antibody in the serum from the VD patient reacted with a more acidic subset of GFAP molecules compared with the anti-GFAP antibody from our patient. In conjunction with the fact that the GFAP molecule with high isoelectric point was insoluble and less degraded, these results suggested that the anti-GFAP antibody in the serum of our patient was not generated due to a secondary response to soluble and degraded GFAP which leaked through the damaged blood-brain barrier as found in the VD patient, but was generated actively on the basis of dysregulation of the immune system. Possible effects of the autoantibody on astrocytic function and the pathogenesis in dementia are discussed.

Alzheimer Disease↗

PubMed1997

Evaluation of post-mortem oxymetry with reference to the causes of death.

We examined blood samples of 214 forensic autopsy cases, excluding fire victims, on a CO-oximeter system in order to evaluate post-mortem oxymetric profiles with reference to the causes of death. Oxyhemoglobin (O2-Hb) levels in the left and right heart blood, respectively, ranged from 0 to 97.7% and from 0 to 92.1%, showing no apparent correlation with the post-mortem intervals or rectal temperatures. In nearly 60% of the cases, O2-Hb was lower than 10%. A high O2-Hb level (over 50%) in the left heart blood was most frequently observed in death from cold exposure and occasionally in fatalities from blunt injuries and stab/incised wounds with or without medical care. O2-Hb in the heart blood was usually very low (under 10%) in fatalities from asphyxiation, drowning, poisoning and natural diseases. A greatest oxymetric variation was observed in death from injuries, probably due to varied causal mechanisms of death. In most cases, the differences between blood O2-Hb levels in the heart and iliac vessels were within 15%; whereas O2-Hb in the cerebral venous blood was usually evidently higher than that in the right heart blood. An inverse relation of O2-Hb levels to total hemoglobin contents was observed slightly for the blood in the heart and iliac vessels, and more obviously for the cerebral venous blood. The above post-mortem oxymetric profiles were considered to at least partially reflect the final balance of oxygen uptake and consumption in dying process, possibly also affected by the circulatory status, giving an objective index to the color of cadaveric blood (hypostasis), although it should be assessed in consideration of post-mortem interference and total hemoglobin contents. In any case, however, post-mortem oxymetry seemed to have a limited value owing to severe systemic hypoxia which would be a common final state before death from various fatal traumas and diseases, maybe except for those with extremely short agony.

Adolescent↗

PubMed1997

Leptin suppresses basal insulin secretion from rat pancreatic islets.

The effects of leptin on insulin secretion from pancreatic islets of Sprague-Dawley rats were examined in vitro. In a basal glucose medium (5.5 mM), insulin secretion from isolated islets was significantly decreased after addition of a recombinant leptin (80 nM) (3.20+/-0.14 nmol/10 islets/h) compared with that before the addition (4.41+/-0.30 nmol/10 islets/h). Although significant leptin suppression of insulin secretion was not observed under a glucose-stimulated (11.1 mM) condition, these results suggest that a negative feedback system may exist between leptin and insulin, which increases the production of leptin from adipose tissues.

Animals↗

PubMed1997

Immunohistochemical evaluation of lymph node micrometastases from gastric carcinomas.

BACKGROUND: The clinicopathologic significance of micrometastases to lymph nodes, consisting of a single carcinoma cell or a small cluster of carcinoma cells and confirmed only by special staining, was evaluated in patients with gastric carcinoma. METHODS: The authors studied 2446 lymph nodes removed during surgery for 109 cases of gastric carcinoma, including Stages I, II, III and IV. Tissue preparations were stained with hematoxylin and eosin (H&E), Alcian blue in combination with periodic acid-Schiff stain, and antibodies against cytokeratin and carcinoembryonic antigen (CEA). RESULTS: Metastases were confirmed in 230 lymph nodes (9.4%) stained with H & E, and an additional 201 lymph nodes (17.6%) had micrometastases identified only by immunostaining for cytokeratin (197 lymph nodes) and/or CEA (66). Carcinomas with micrometastases had significantly worse prognoses at Stage II. Between the two histologic types of gastric carcinoma, the diffuse type had more micrometastases than the intestinal type. CONCLUSIONS: The findings of this study indicate that the presence of micrometastases in lymph nodes is an indispensable factor in determining the prognosis of gastric carcinoma patients.

Adult↗

PubMed1997

The origin of chlorarachniophyte plastids, as inferred from phylogenetic comparisons of amino acid sequences of EF-Tu.

A molecular phylogenetic analysis of elongation factor Tu (EF-Tu) proteins from plastids was performed in an attempt to identify the origin of chlorarachniophyte plastids, which are considered to have evolved from the endosymbiont of a photosynthetic eukaryote. Partial sequences of the genes for plastid EF-Tu proteins (1,080-1,089 bp) were determined for three algae that contain chlorophyll b, namely, Gymnochlora stellata (Chlorarachniophyceae), Bryopsis maxima (Ulvophyceae), and Pyramimonas disomata (Prasinophyceae). The deduced amino acid sequences were used to construct phylogenetic trees of the plastid and bacterial EF-Tu proteins by the maximum likelihood, the maximum parsimony, and the neighbor joining methods. The trees obtained in the present analysis suggest that all plastids that contain chlorophyll b are monophyletic and that the chlorarachniophyte plastids are closely related to those of the Ulvophyceae. The phylogenetic trees also suggest that euglenophyte plastids are closely related to prasinophycean plastids. The results indicate that the chlorarachniophyte plastids evolved from a green algal endosymbiont that was closely related to the Ulvophyceae and that at least two secondary endosymbiotic events have occurred in the lineage of algae with plastids that contain chlorophyll b.

Amino Acid Sequence↗

PubMed1997

Ventilatory response at the onset of voluntary exercise and passive movement in endurance runners.

The present study was performed to examine whether or not the ventilatory response at the onset of voluntary exercise and passive movement in endurance runners is the same as in untrained subjects. Twelve long-distance runners belonging to the varsity athletic club and 13 untrained subjects of our university participated as subjects in this study. Maximum oxygen uptake was significantly higher in the endurance runner group [mean (SD) 70.8 (4.7) ml.kg-1.min-1] than in the untrained group [49.8 (6.3) ml.kg-1.min-1]. Cardiorespiratory responses during voluntary exercise and passive movement of alternate flexion-extension of the right and left legs for about 15 s at a frequency of about 60 rpm, were determined by means of breath-by-breath techniques. Minute inspiratory ventilation (VI), tidal volume (VT), respiratory frequency (fb), cardiac output (Qc), stroke volume (SV) and heart rate (HR) increased significantly immediately at the onset of voluntary exercise and passive movement. The incremental rate for VI was greater than that for Qc. Average values and standard deviations of changes in VI were calculated as the difference between the mean of the first and second breath and the mean of five breaths preceding the exercise or movement. The rates obtained in voluntary exercise and passive movement in the endurance runner group [2.34 (0.82) and 1.72 (0.71 l.min-1), respectively] were significantly (P < 0.05) lower than those in the untrained group [4.16 (2.66) and 2.71 (1.56 l.min-1), respectively]. Also changes in VT and HR were significantly lower in the endurance group than in the untrained group with regard to both voluntary exercise and passive movement. The results suggest that the magnitude of cardiorespiratory responses at the onset of voluntary exercise and passive movement in humans is influenced by chronic endurance training for long periods.

Adult↗

PubMed1997

Effects of combined beta-adrenergic and cholinergic blockade on the initial ventilatory response to exercise in humans.

To elucidate whether combined adrenergic and parasympathetic blockade would affect the ventilatory response to exercise, especially at the initial stage (phase I), six healthy subjects performed a brief and light voluntary bilateral leg extension exercise and passive movements under the conditions of control (before the blockade) and after intravenous administration of combined beta-adrenergic (propranolol, 0.2 mg.kg-1) and muscarinic (atropine, 0.04 mg.kg-1) receptor antagonists. The movements were continued only within two breaths after the onset of the motion. Ventilation increased immediately and significantly (P < 0.05) within the first breath at the onset of voluntary exercise in all conditions as compared with at rest. However, the magnitude of increase in mean ventilation within two breaths at the start of exercise as against the resting value (delta ventilation) was significantly less (P < 0.05) after the combined blockades (2.5 l.min-1) than in the control condition (3.7 l.min-1). Passive movements showed a similar but smaller change as compared with voluntary exercise. The heart rate response to exercise was attenuated by the combined blockade while cardiac output showed a slight change at the onset of exercise. It is concluded that phase I should occur despite the inhibited activity of the beta-adrenergic and the cholinergic systems; nevertheless, the response was attenuated by the combined blockade. These results suggest a possible role of the beta-adrenergic and/or cholinergic systems in the rapid increase in ventilation that occurs at the start of exercise.

Adrenergic beta-Antagonists↗

PubMed1997

Cytokine responses in mice infected with Angiostrongylus cantonensis.

For determination of the kinetics of cytokine production and its possible role in host resistance to Angiostrongylus cantonensis in the mouse, Th1 [interleukin 2 (IL-2) and interferon gamma (IFN-gamma] and Th2 (IL-5 and IL-4) cytokine production in the cerebrospinal fluid (CSF), sera, and culture supernatants of spleen cells (SC) or cervical lymph-node cells (CLNC) of infected BALB/c and C57BL/6 mice was assessed by a sandwich enzyme-linked immunosorbent assay (ELISA). IL-5 and IL-4 were detected in CSF of both strains, with a peak response occurring at around days 12-15 and 20 postinfection (p.i.), respectively. A reverse transcriptase-polymerase chain reaction (RT-PCR) assay also revealed prominent IL-5 and IL-4 mRNA expression in T-cells but not in eosinophils in CSF. SC and CLNC stimulated with A. cantonensis young adult-worm antigen released IL-5 in vitro at and after day 20 p.i. Contrarily, IFN-gamma production in CSF and SC or CLNC culture supernatants was almost negligible before day 30 p.i. IL-5, IL-4, and IL-2 production in culture supernatants was rather prominent in resistant C57BL/6 mice as opposed to susceptible BALB/c mice as assessed by the magnitude of increase over preinfection levels. Antigen-specific IgG1 (but not IgG2a) responses were more prominent in C57BL/6 mice than in BALB/c mice. These data suggest that systemic and local Th2 cytokine responses, especially those involving IL-5, are predominant in A. cantonensis-infected mice and that IL-5 is an important cytokine underlying the innate resistance of the mouse against A. cantonensis.

Angiostrongylus cantonensis↗

PubMed1997

Esophageal carcinosarcoma: a genetic analysis.

Carcinosarcoma of the esophagus is a rare malignant neoplasm that consists of both carcinomatous and sarcomatous elements. The histogenesis of the sarcomatous component is generally considered to result from metaplasia of carcinomatous cells toward mesenchymal differentiation. True carcinosarcoma, characterized as a collision between a carcinoma and a sarcoma, is extremely rare. We describe a patient with primary achalasia who developed a true carcinosarcoma of the esophagus in which clonal differences between carcinomatous and sarcomatous elements were genetically and immunohistochemically demonstrated. A polypoid tumor located in the middle third of the esophagus developed in a 51-year-old man with longstanding achalasia. The tumor was predominantly composed of spindle-shaped sarcomatous cells. Squamous cell carcinoma in situ and islands of well-differentiated squamous cell carcinoma in the sarcomatous element were histologically observed. The sarcomatous element was immunoreactive for both mesenchymal and myoid markers. The carcinomatous component expressed type I and type II cytokeratins as well as epithelial membrane antigen. Analysis for chromosomal loss of heterozygosity performed in multiple microdissected samples of each sarcomatous and carcinomatous element revealed distinct genetic clonalities. These differences in immunohistochemical and genetic clonalities suggest that the tumor composed of squamous cell carcinoma and leiomyosarcoma originated separately from epithelial and mesenchymal precursors.

Carcinosarcoma↗

PubMed1997

Induction of cerebrospinal fluid eosinophilia in rats by the intraventricular injection of Angiostrongylus cantonensis antigen.

Resistance to Angiostrongylus cantonensis is contingent upon the generation of an eosinophilic response in the CSF of infected hosts. We have studied the parameters required for the generation of this CSF eosinophilia in normally permissive rats. We initially induced a marked peripheral eosinophilia in rats by infection with either Mesocestoides corti or Angiostrongylus cantonensis or the surgical transfer of A. cantonensis young adult worms (YA) into their pulmonary arteries. Next, we injected various antigens into the ventricles of these rats. A. cantonensis-preinfected rats demonstrated significant CSF eosinophilia following injection of A. cantonensis egg antigen, 1st-stage larval (L1) antigen, or M. corti antigen, but not following YA antigen inoculation. A. cantonensis egg and M. corti antigens were potent chemoattractants for eosinophils in an in vitro chemotaxis assay. These data indicate that peripheral eosinophilia, meningeal stimulation by A. cantonensis infection and the presence of potent chemoattractants, e.g., egg and L1 antigens are prerequisites for CSF eosinophil accumulation in permissive rat hosts.

Angiostrongylus cantonensis↗

PubMed1997

A randomized trial of surgery with and without chemotherapy for localized squamous carcinoma of the thoracic esophagus: the Japan Clinical Oncology Group Study.

OBJECTIVE: To determine whether postoperative adjuvant chemotherapy confers a survival benefit on patients with esophageal squamous cell carcinoma undergoing radical surgery, we undertook a cooperative, prospective randomized controlled trial. METHODS: A total of 205 patients underwent transthoracic esophagectomy with lymphadenectomy at eleven institutions between December 1988 and July 1991. These patients were prospectively randomized into two groups (100 patients underwent surgery alone and 105 patients had additional two courses of combination chemotherapy with cisplatin (70 mg/m2) and vindesine (3 mg/m2). The two groups did not differ with respect to sex, age, location of tumor, and distributions of pT, pN, pM, or p stage. RESULTS: The 5-year survival was 44.9% in the surgery alone group and 48.1% in the surgery plus chemotherapy group. The relative risk was estimated to be 0.89 (95% confidence interval, 0.61 to 1.31) in the surgery plus chemotherapy group compared with the surgery alone group. No significant differences in survival were detected between the two groups, even with lymph node stratification. CONCLUSION: Postoperative adjuvant chemotherapy with cisplatin and vindesine has no additive effect on survival in patients with esophageal cancer compared with surgery alone.

Adult↗