Search PubMed⌕ Search

Biomedical subjects

H Ikeda

Publications and source records attributed to H Ikeda.

At least 415 records · Page 23Linked to original sources
PubMed1998

Cryopreservation and ensuing in vitro fertilization ability of boar spermatozoa from epididymides stored at 4 degrees C.

The influence of prolonged storage of boar epididymides on post-thaw sperm motility, and in vitro fertilization was evaluated. Twenty pairs of epididymides were obtained from Large White boars, and spermatozoa from one of each of the pairs were immediately collected and frozen (control group). The remaining epididymides were cooled to 4 degrees C and stored for 1, 2 or 3 d, after which spermatozoa were collected and frozen (experimental groups Day 1, 2 and 3, respectively). Sperm motility was maintained throughout the dilution procedure and then dropped (P < 0.01) after freezing and thawing. During storage the motility of nonfrozen spermatozoa decreased significantly (P < 0.01), reaching a value equal to that of frozen-thawed spermatozoa on Day 3. In vitro fertilization experiments revealed significantly (P < 0.05) lower penetration rates using Day 1, 2 and 3 stored spermatozoa (12, 13 and 2%, respectively) than that of the control group (40%). Oocyte penetration ability seemed to be reflected by acrosome integrity. However, the motility of spermatozoa with the ability to penetrate oocytes in Day 1 and Day 2 groups did not differ from that of the controls. The motility of spermatozoa lacking penetration ability, on the other hand, gradually decreased as the storage period was prolonged. This suggests that the sperm motility and penetration ability are affected by different mechanisms during the cold storage of epididymides. Finally, control and experimental groups exhibited high incidences of monospermic penetration (64 to 90%) and of male pronuclear formation (67 to 71%). These data suggest that cryopreservation of spermatozoa from boar epididymides stored at 4 degrees C for 1 to 2 d can be used for conserving male germ cells when epididymal spermatozoa can not be collected immediately and cryopreserved.

Acrosome↗
PubMed1998

Subjective sensation and objective neural discharges recorded from clinically nonvital and intact teeth.

The aim of this study was to compare subjective sensation with objective neural discharges recorded by microneurography. We examined human teeth that did not respond to pulp vitality testing, but that responded to cavity preparation for endodontic treatment (pathophysiological). Intact teeth and endodontically obturated teeth were used as controls. Pulpal blood flow in the clinical crown and histological examination were also used. Most teeth, both in normal and pathophysiological conditions, did not respond to all pulp vitality tests. Even when teeth in the pathophysiological group showed spike discharges evoked by pulp vitality tests or from spontaneous activity no sensation was elicited. These results confirmed the usefulness of microneurography for research on pulpal sensation and the significance of summation in the perception of sensation in chronically inflamed tooth pulp.

Action Potentials↗
PubMed1998

Spheno-orbital meningioma with unusual radiological features.

We report a patient with a spheno-orbital meningioma having unusual clinical and radiological features. Eight days before consultation, this 66-year-old female developed right exophthalmos associated with periorbital pain. Neuroradiological features included, (1) multilocular intratumoral cyst on enhanced CT, (2) preferential extradural growth with prominent bony destruction and intratumoral hemorrhage on MRI. and (3) early venous draining on CAG. Histopathology including immunohistochemistry and electron microscopy revealed typical transitional meningioma. The only uncommon pathological feature was that the attachment consisted of the outer (periosteal) layer of the dura, and the microscopic structure of the inner (meningeal) layer was normal.

Aged↗
PubMed1998

Generators of visual evoked potentials investigated by dipole tracing in the human occipital cortex.

Current source generators (dipoles) of the human visual evoked potentials to pattern-onset stimuli were investigated with the dipole tracing method, using a realistic four-layer head model of scalp-skull-fluid-brain, which can equate the surface potential distributions on a scalp to one or two corresponding equivalent dipoles. Three healthy adult human subjects were used, and 29 electrodes were set on a scalp of each subject. Visual stimulus of a checkerboard pattern was presented for 250 ms in each of eight different visual fields (central and peripheral parts of each of four quadrant fields). The visual evoked potentials consisting of initial positive-late negative waves (CI and CII components designated by Jeffreys and Axford) were recorded mainly on the occipital region contralateral to stimulated visual fields. The initial positive wave (CI) of visual evoked potentials were divided into two components: early component of the CI (e-CI--an early small positive deflection with approximate peak latency of 70-90 ms) and late component of the CI (l-CI--a late large positive deflection with approximate peak latency of 100-120 ms). The dipole with a fit exceeding 98% dipolarity with our model at the shortest latencies was defined as an "earliest dipole" of the evoked potentials, produced by the primary responses in the occipital cortex to an afferent volley from the lateral geniculate body. These earliest dipoles, for eight different visual field stimulations, were estimated at the approximate peak of the e-CI. Estimated dipoles were superimposed on a three-dimensional magnetic resonance image of each subject's brain. Earliest dipoles for right upper and right lower quadrant-field stimulations were located at the left calcarine cortices below and above the calcarine fissure, respectively; earliest dipoles for left upper and left lower quadrant-field stimulations were located at the right calcarine cortices below and above the calcarine fissure, respectively. Furthermore, earliest dipoles for central and peripheral quadrant-field stimulations were located posteriorly and anteriorly in the calcarine cortex, respectively. The results from these non-invasive analyses of visual evoked potentials indicated topographic localization of the dipoles around the calcarine fissure based on the loci of the visual fields. This was comparable to the retinotopy of the human occipital lobe based on clinicopathological studies.

Adult↗
PubMed1998

Induction of immune-mediated hearing loss in SCID mice by injection of MRL/lpr mouse spleen cells.

Induction of immune-mediated hearing loss in SCID mice by injection of MRL/lpr mouse spleen cells The MRL/lpr mouse, which has a mutation in the Fas gene encoding a cell-surface receptor for apoptosis, shows an accumulation of abnormal immunocompetent cells and SLE-like disease. It has recently been reported that this mouse also manifests sensorineural hearing loss (SHL) with cochlear pathology at 20 weeks of age. We examined the effects of injecting MRL/lpr spleen cells on the development of SHL in severe combined immunodeficient (SCID) mice, which originally develop neither SHL nor cochlear pathology. Immune-mediated SHL and cochlear pathology were, indeed, transferred to the SCID mice by the injection of spleen cells from the MRL/lpr mice. These findings suggest that cell-mediated immunity is involved in the development of SHL and cochlear pathology.

Animals↗
PubMed1998

Peripheral blood levels of matrix metalloproteases-2 and -9 are elevated in patients with acute coronary syndromes.

OBJECTIVES: This study was sought to investigate whether peripheral blood levels of matrix metalloproteases (MMPs) are affected in patients with acute coronary syndromes (ACS). BACKGROUND: Synthesis of MMPs has been reported in coronary atherosclerotic lesions in patients with unstable angina (UA), suggesting a pathogenic role of MMPs in the development of ACS. METHODS: Using sandwich enzyme immunoassay, serum MMP-2 and plasma MMP-9 were measured in 33 patients with ACS (22 with acute myocardial infarction [AMI], 11 with UA), 17 with stable effort angina (EA) and 17 normal control subjects. RESULTS: Serum MMP-2 in patients with UA and AMI on day 0 was two times greater than that in control subjects, and patients with EA showed higher MMP-2 levels than those in control subjects. Plasma MMP-9 in patients with UA and AMI on day 0 was elevated by threefold and twofold versus that in control subjects, respectively. In patients with UA and AMI who underwent medical treatment (n = 11 and 13, respectively), MMP-2 elevation was sustained until day 7. In patients with UA, MMP-9 elevation on day 0 was followed by a gradual decrease toward the control range up to day 7. Some patients with AMI showed a transient MMP-9 elevation with a peak on day 3, whereas in others, MMP-9 levels were significantly elevated on day 0 and remained higher than those in control subjects up to day 3. CONCLUSIONS: Serial changes in serum MMP-2 and plasma MMP-9 were documented in patients with ACS. These findings provide an insight into the molecular mechanism of plaque destabilization.

Angina Pectoris↗
PubMed1998

Exercise-induced abnormal blood pressure responses are related to subendocardial ischemia in hypertrophic cardiomyopathy.

OBJECTIVES: We examined by thallium-201 scintigraphy whether exercise-induced abnormal blood pressure response (BPR) is related to myocardial ischemia. BACKGROUND: Hemodynamic instabilities during exercise in patients with hypertrophic cardiomyopathy (HCM) are considered to be caused by abnormal reflex control of vascular resistance. METHODS: In 105 patients with HCM, exercise thallium scintigraphy was performed by means of a multistage, symptom-limited bicycle ergometer exercise test. RESULTS: Eighty-eight patients had normal BPR (> or = 25 mm Hg from baseline to peak exercise), and 17 had abnormal BPR (<25 mm Hg). Clinical characteristics including age, the prevalence of obstruction, New York Heart Association functional class and echocardiographic measurements were similar between the two groups. Left ventricular end-diastolic pressure was significantly higher in patients with abnormal BPR than in those with normal BPR (18+/-8 vs. 14+/-5 mm Hg, p < 0.05). Exercise-induced perfusion abnormalities including fixed and reversible perfusion defects, and left ventricular cavity dilatation (LVCD) were identified in 72 (69%) of 105 study patients. Left ventricular cavity dilatation indicates subendocardial hypoperfusion and is a marker of diffuse subendocardial ischemia. The prevalence of fixed or reversible perfusion defects was similar between the two groups. Patients with abnormal BPR had the higher prevalence of LVCD as compared to those with normal BPR (47.1 vs. 10%, p < 0.0002). Multiple logistic regression analysis revealed that LVCD was independently associated with abnormal BPR (odds ratio 3.76, 95% confidence interval 1.61 to 8.76). CONCLUSIONS: Exercise-induced abnormal BPRs in patients with HCM are related to subendocardial ischemia during exercise.

Adolescent↗
PubMed1998

Brainstem lesion in Aicardi-Goutières syndrome.

Aicardi-Goutières syndrome is characterized by the calcification of basal ganglia, leukodystrophy, and lymphocytosis in cerebrospinal fluid. No brainstem lesion has been described. We report a Japanese girl who presented with delayed development and microcephalus at early infancy. Magnetic resonance imaging revealed T2-weighted high intensity in the cerebral white matter and brainstem, and nerve conduction velocity was delayed in the central nervous system, indicating that she manifested dysmyelination in the brainstem white matter similar to that in the cerebral white matter.

Basal Ganglia Diseases↗
PubMed1998

Networking antioxidants in the isolated rat heart are selectively depleted by ischemia-reperfusion.

Although cardiac endogenous antioxidants have been reported to be oxidized and decreased by ischemia-reperfusion, little is known whether the changes in these antioxidants are correlated with each other in a systematic relationship. In this study, isolated rat hearts were subjected to various periods of ischemia-reperfusion using the Langendorff method, and the content and/or redox status of tissue antioxidants were analyzed. Significant losses in the tissue hydrophilic antioxidants, ascorbate, and glutathione were observed. These losses were dependent on the duration of the reperfusion period (between 0-40 min) but not of ischemia (20-60 min). Marked increases of dehydroascorbate and glutathione disulfide, the oxidized forms of ascorbate and glutathione, respectively, were found during reperfusion, but these changes were not observed during ischemia. These findings indicate that the tissue hydrophilic antioxidants are easily oxidized and may be the first line of antioxidant defenses during reperfusion. Lipophilic antioxidants, like ubiquinol 9 and vitamin E, were not decreased during ischemia-reperfusion using regular buffer; however, if oxidative stress was induced by addition of H2O2 to the buffer solution during reperfusion after 20 min of ischemia, decreases in both the hydrophilic and hydrophobic antioxidants were noticeable. With 100 microM H2O2, the tissue antioxidant decreases were ubiquinol 9 (39%), vitamin E (3%), glutathione (44%) and ascorbate (58%). Only with 500 microM H2O2 treatment were marked decreases in tissue vitamin E (65%) observed; this was associated with almost complete depletion of tissue ubiquinol 9 (95%). These results suggest that prior to the consumption of vitamin E, other antioxidants are depleted and that vitamin E may serve as the ultimate antioxidant, protecting the integrity of cellular membranes. Thus, in this work, cardiac antioxidants were demonstrated to change in a systematically organized relationship under ischemia-reperfusion. This graded utilization of antioxidants supports the redox based antioxidant network concept, found to be present in other biological systems.

Animals↗
PubMed1998

A comparative study of epithelialization of subcutaneous fascial flaps and muscle-only flaps in the oral cavity. A rabbit model.

Epithelialization of subcutaneous fascial flaps and muscle-only flaps used for reconstruction of the oral mucosa were studied in a rabbit model. Angiography was performed to help to design a subcutaneous cervical fascial flap and a cleidomastoid muscle-only flap. These flaps were transferred into a mucoperiosteal defect on the mandibular alveolus. The flaps were gradually infiltrated by acute inflammatory cells from the periphery and then replaced by granulation tissue originating from the oral mucosa. The epithelialization was by secondary intention. An epithelial tongue from the surrounding epithelium migrated onto the granulating flaps with eventual coverage after three weeks. After two months, the muscle-only flap was covered by a poorly organized epithelium, different from the highly uniform epithelium in the fascial flap. The granulation tissue which replaced the muscle-only flap matured to fibrous tissue, associated with severe contraction. This was characterized by dense regular collagen fibers, no elastic fibers, and few capillaries, while the fibrous tissue which replaced the fascial flap was characterized by random collagen and elastic fiber morphology and numerous dilated blood vessels, and was associated with mild contraction. This experiment supports the view that the different extracellular matrices of these flaps may play a role in epithelial configuration and contraction.

Animals↗
PubMed1998

Treatment of ulcerative colitis with germinated barley foodstuff feeding: a pilot study.

BACKGROUND: Germinated barley foodstuff (GBF) has been shown to attenuate intestinal injury in animal models, largely by increasing luminal short-chain fatty acid production. AIM: To investigate the safety and efficacy of GBF in the treatment of ulcerative colitis (UC). METHODS: Ten patients with active UC received 30 g of GBF daily for 4 weeks in an open-label treatment protocol while the baseline anti-inflammatory therapy was continued. The response to treatment was evaluated clinically and endoscopically. Pre- and post-treatment stool concentrations of short-chain fatty acids were measured by gas-liquid chromatography. RESULTS: Patients showed improvement in their clinical activity index scores, with a significant decrease in the score from 6.9+/-1.4 to 2.8+/-1.5 (mean+/-S.E.M., P < 0.05). The endoscopic index score fell from 6.1+/-2.3 to 3.8+/-2.3 (P < 0.0001). Patients showed an increase in stool butyrate concentrations after GBF treatment (P < 0.05). No side-effects were observed. CONCLUSIONS: Oral GBF therapy may have a place in management of ulcerative colitis, but controlled studies are needed to demonstrate its efficacy in the treatment of this disorder.

Adult↗
PubMed1998

PRAME, a gene encoding an antigen recognized on a human melanoma by cytolytic T cells, is expressed in acute leukaemia cells.

Gene PRAME was found to encode an antigen recognized on a human melanoma cell line by an autologous cytolytic T-lymphocyte clone. This gene is expressed at a high level in a very large fraction of tumours, such as melanomas, non-small-cell lung carcinomas, sarcomas, head and neck tumours and renal carcinomas. It is therefore a candidate for tumour immunotherapy even though some low expression is found in certain normal tissues. We tested by RT-PCR the expression of PRAME on more than 250 bone marrow or blood samples from patients with a haematological malignancy. Approximately 25% of the acute leukaemia samples were positive. Remarkably, all acute myeloblastic leukaemias that carried the chromosomal translocation t(8;21), which fuses the genes AML1 and ETO, expressed PRAME at a high level.

Acute Disease↗
PubMed1998

Double-strand break repair mediated by DNA end-joining.

DNA double-strand breaks formed by ionizing irradiation or other stresses are repaired by homologous recombination or DNA end-joining. This review focuses on the mechanism of double-strand break repair mediated by DNA end-joining, in which many factors have recently been identified. After DNA double-strand breakage, DNA end-joining takes place between the DNA ends that have nonhomologous sequences or very short regions ofhomology. The broken DNA is repaired if the DNA end-joining occurs in the same molecule, while it causes chromosome aberrations such as deletions, insertions, translocations and inversions if it occurs between different molecules. Rad50 and its relatives, Ku-proteins, DNA ligase VI and silencing factors, are involved in DNA end-joining in yeast and mammalian cells. These findings led us to propose a model in which the formation of a heterochromatin-like complex at broken ends is an important element in DNA end-joining.

Animals↗
PubMed1998

Escherichia coli HU protein suppresses DNA-gyrase-mediated illegitimate recombination and SOS induction.

BACKGROUND: The HU protein is an abundant DNA binding protein of bacteria and is a major constituent of the bacterial nucleoid. HU protein is known to be involved in several fundamental biological functions, including DNA supercoiling, DNA replication, site-specific DNA inversion, and transposition. It is generally thought that a functional relationship exists between HU protein and DNA gyrase. RESULTS: We found that an hupA hupB double mutant displays enhanced spontaneous illegitimate recombination during the formation of lambdabio transducing phage in Escherichia coli. Nucleotide sequence analysis of the resulting transducing phages showed that the E. coli bio and lambda recombination sites did not have any homologous sequence. This mutation also enhanced the spontaneous expression of SOS functions. Furthermore, either overproduced GyrA protein or a temperature-sensitive gyrB mutation suppressed the illegitimate recombination enhanced by the defect of HU protein. CONCLUSION: These results show that the defect of HU induces illegitimate recombination and SOS response, which are probably mediated by DNA gyrase, implying that HU protein plays roles in suppression of illegitimate recombination and SOS response through interaction with DNA gyrase.

Bacterial Proteins↗
PubMed1998

Beneficial effect of long-term combined treatment with voglibose and pioglitazone on pancreatic islet function of genetically diabetic GK rats.

Effects of voglibose (an alpha-glucosidase inhibitor) and pioglitazone (an insulin sensitizer) on glycemic control and on the function of pancreatic islets were evaluated using Goto-Kakizaki (GK) rats with non-insulin-dependent diabetes mellitus (NIDDM). Five week administration (8-13 weeks of age in GK rats) of voglibose alone (added to the chow at a concentration of 10 ppm), pioglitazone alone (10 mg/kg daily p.o.), or both of the agents together significantly improved fasting plasma glucose levels and those at 120 min in oral glucose tolerance tests. Insulin secretory capacity in response to glucose of the isolated islets, assessed by batch incubation, was significantly improved in the voglibose and in the voglibose plus pioglitazone groups. Eight-week administration (5-13 weeks of age) of voglibose and voglibose plus pioglitazone successfully lowered the fasting levels of plasma glucose and triglyceride. The glucose-responsiveness in insulin release from the islets was also significantly recovered by the therapy. The treatment increased the insulin content of the islets to almost twice that in untreated controls. Thus, treatment by these drugs can not only effectively ameliorate the metabolic derangement of NIDDM in GK rats, but it can also restore the deteriorated islet function, possibly through protection from glucose toxicity.

Animals↗
PubMed1998

Neuronavigation using an articulated arm with a bayonet probe on a computer graphic composite of magnetic resonance and computerized tomography images.

This report describes a neurosurgical navigational system using a newly-designed articulated arm with an interchangeable probe shaped like a bayonet, which can be used in deep structures through narrow openings. This system enables three-dimensional integration of magnetic resonance and computed tomographical images, and thereby yields computer graphic composites of the scalp, brain, skull, and vessels. The arm was used in 15 patients during open brain surgery, including 5 skull base procedures. This system was useful for comprehension of skull base anatomy and could conveniently be used in microscopic neurosurgical procedures without limiting the operative field.

Adult↗