Search PubMed⌕ Search

Biomedical subjects

H Yoshioka

Publications and source records attributed to H Yoshioka.

At least 181 records · Page 10Linked to original sources
PubMed1996

MR imaging of non-cancerous hepatic lesions in Long-Evans cinnamon rats.

We measured MR images of the liver of Long-Evans Cinnamon (LEC) rats with pathologic correlation and assessed the effectiveness of MR imaging (MRI) for diagnosis of noncancerous hepatic lesions. T1- and T2-weighted images of their livers were obtained, and the dynamic and delayed studies after intravenous gadolinium injection were also performed. Cholangiofibrosis showed low signal intensity on T1-weighted images and high signal intensity on T2-weighted images. The T2 relaxation time of cholangiofibrosis was significantly prolonged (p < .01), and the signal intensity ratio of this lesion to muscle on T1-weighted images was significantly lower than that of normal liver parenchyma to muscle (p < .01). The lesion was enhanced immediately after gadolinium injection and the enhancement was prolonged. Among three cases of peliosis hepatis identified, one showed heterogeneous intensities on both T1- and T2-weighted images and the other two showed similar intensity pattern to cholangiofibrosis. The characteristic MR appearance of cholangiofibrosis may be useful to distinguish it from hepatocellular carcinoma (HCC).

Animals↗
PubMed1996

Lenńox-Gastaut syndrome associated with leukoencephalopathy.

We report a 13-year-old boy with Lennox-Gastaut syndrome (LGS) associated with leukoencephalopathy. He was diagnosed with unclassified acute lymphocytic leukemia at the age of 3 years. After initial chemotherapy, he received intravenous methotrexate (total dosage 1,035 mg), intrathecal methotrexate (total dosage 221 mg), and whole brain irradiation (2,400 cGy). From about the age of 8 years, he developed slurred speech, hyperactivity, and mental deterioration. Cranial CT revealed calcification of the subcortical white matter. At age 9 years, he exhibited tonic seizures and atonic seizures. EEG showed diffuse slow spike-wave discharges, which are characteristic of LGS. Although multiple antiepileptic drugs have been prescribed, the frequency of seizures remains unchanged and his mental state is becoming progressively worse.

Adolescent↗
PubMed1996

Seizure susceptibility during recovery from hypercapnia in neonatal dogs.

Seizure susceptibility during recovery from hypercapnia was investigated in seven anesthetized neonatal dogs; 13, 20, or 30% CO2 gas was administered for 30 min through a ventilator to result in three levels of hypercapnia in which measured PaCO2 values were approximately 70, 100, and 140 mm Hg. Thereafter, the animals were allowed to recover for 45 min; during this recovery phase, electrocorticography was performed. In five of seven dogs, approximately 1.5 Hz slow irregular spike and wave bursts appeared at 6 min after abrupt withdrawal from hypercapnia and lasted several minutes. This seizure activity was followed by a brief period of electrical suppression. This phenomenon was most often observed during the recovery from moderate hypercapnia and between the PaCO2 values of 100 and 50 mm Hg. When seizure activities appeared in the electrocorticogram, arterial blood pressure increased -40 mm Hg from the preseizure level. These results suggest that neonatal seizures may occur during recovery from hypercapnia.

Acidosis↗
PubMed1996

Increased expression of type VI collagen genes in cutis laxa fibroblasts.

Type VI collagen gene expression in cutis laxa was studied by measuring messenger RNA (mRNA) and protein production levels in four fibroblast strains from patients with congenital cutis laxa and comparing them with those in fibroblasts obtained from age-matched healthy subjects. Levels of type VI collagen mRNA were increased in all cutis laxa fibroblast strains and the levels of alpha 1 (VI) and alpha 3 (VI) chain mRNAs increased in parallel. Increases in type VI collagen mRNAs correlated well with production levels of the corresponding proteins, as determined by immunological assay. These results suggest that increased type VI collagen gene expression is one of the characteristics of cutis laxa dermal fibroblasts and that this abnormality may be related to the skin changes in cutis laxa.

Child, Preschool↗
PubMed1996

Treatment of nodular hepatocellular carcinoma larger than 3 cm with ultrasound-guided percutaneous acetic acid injection.

To assess the efficacy of ultrasound-guided percutaneous acetic acid (15%, 20%, 30%, 40%, and 50% in concentration) injection for a large nodular hepatocellular carcinoma (HCC), percutaneous acetic acid injection was performed using 15% to 50% acetic acid in 28 patients who had one single nodular HCC larger than 3 cm or one main tumor with fewer than two HCCs smaller than 3 cm during the past 7.5 years; the main tumor was slightly hypervascular in nine patients and was highly hypervascular, showing viable cancer cells despite transcatheter arterial embolization in 19 patients. During the series of treatment sessions for each patient, the same concentration of acetic acid was used. Eight (89%) of nine slightly hypervascular main tumors, 18 (95%) of 19 highly hypervascular main tumors, and all 14 small tumors were treated successfully. No serious complications occurred as a direct sequela to acetic acid injection. The 1-, 2- and 3-year recurrence rate from the original main tumor was 0%, 20%, and 20%, respectively, in patients treated with percutaneous acetic acid injection alone and 12%, 24%, and 24% in patients treated with percutaneous acetic acid injection after transcatheter arterial embolization (P = NS). The 1-, 2-, 3-, 4-, and 5-year survival rates were 100%, 80%, 80%, 80%, and 0%, respectively, in the former and 90%, 81%, 81%, 61%, and 61% in the latter (P = NS). Percutaneous acetic acid injection (15% to 50%) may be an effective therapy for slightly hypervascular nodular HCCs larger than 3 cm and highly hypervascular nodular HCCs larger than 3 cm that remain partly viable after transcatheter arterial embolization.

Acetic Acid↗
PubMed1996

In utero exposure to low-doses of ionizing radiation decelerates neuronal migration in the developing rat brain.

In order to elucidate the possible mechanisms for the effects of low doses of ionizing radiation on the developing rat cerebral cortex we studied how neuronal migration can be affected by prenatal in utero irradiation. We have demonstrated an effect of ionizing radiation on neuronal migration at doses as low as 15 cGy together with a changing pattern of expression of the neural cell adhesion molecule N-CAM. After a dose of 15 cGy or more there was a reduction in N-CAM immunoreactivity in the matrix cell zone which became apparent about 24 h after exposure and continued until 48 h after exposure. Normal reactivity occurred 3 days after exposure to radiation. However, there was no obvious change in the immunoreactivity for L1, MAP2, tau protein or neurofilament. Our findings suggest the possible role of N-CAM in neuronal migration and also suggest the presence of a threshold in terms of the effects of small radiation doses on the developing cerebral cortex.

Animals↗
PubMed1996

A cytosolic phospholipase A2 from potato tissues appears to be patatin.

Phospholipase (PL) A2 is involved in signal transduction in the resistance reaction that is induced in potato by inoculation of an incompatible race of Phytophthora infestans, the late blight fungus, or by treatment with fungal elicitor hyphal wall components (Kawakita et al. 1993). In this study, PLA2 in the soluble fraction from potato tuber was purified. The following results suggested that the enzyme was, in fact, patatin: (1) the molecular mass of the purified enzyme was 40 kDa, the same as that of patatin; (2) the pI of the purified enzyme was approximately 4.75, which corresponds to that of patatin; and (3) the amino-terminal amino acid sequence of the purified enzyme showed a high degree of homology to that of patatin. Patatin is known as a storage protein of the potato tuber and it has been shown to have esterase activity. However, other enzymatic activities and the function(s) of patatin are unknown. We investigated the PLA activities of the purified patatin. The PLA2 activity of the patatin was much higher than the PLA1 activity, even though the protein exhibited both activities. The PLA2 activity of the enzyme was particularly apparent when phosphatidylcholine with linoleic acid at the sn-2 position was used as substrate. Lower activity was observed with phosphatidylcholine with palmitic acid, oleic acid and arachidonic acid at the sn-2 position.

Amino Acid Sequence↗
PubMed1996

Magnetic resonance imaging of isolated skeletal muscles. Osmotic influence.

RATIONALE AND OBJECTIVES: The authors evaluate the contribution of intracellular water to the change of T2 relaxation time. METHODS: Magnetic resonance images of frog muscles (n = 16) were obtained in hypotonic, isotonic, and hypertonic solutions, and their leg weights and T2 relaxation times were measured. Likewise, these values were measured after electric stimulation for 2 to 10 minutes in isotonic solution (n = 5). RESULTS: The muscle weights increased in the hypotonic solutions, whereas they showed no change in isotonic solution. T2 relaxation times, however, showed little change in either isotonic or hypotonic solutions. In electrically stimulated muscles, T2 relaxation times increased, accompanying the increase in muscle weight in isotonic solutions. CONCLUSION: Muscle contraction results in increased T2 relaxation time, but intracellular water hardly contributes to the increase in this value. Therefore, an increase in extracellular water may be the main cause of the increase in T2 relaxation time seen in exercised muscles.

Animals↗
PubMed1996

A new model of transient cerebral ischemia in neonatal rats.

A new model of transient cerebral ischemia in 10-day- old rats is described. Under microscopic guidance, the right external and internal carotid arteries were electrically coagulated. A solid 0.47 mm diameter nylon thread was inserted into the right common carotid artery toward the ascending aorta up to 10-12 mm from the upper edge of the sternomastoid muscle (preischemic rats). A 60-min cerebral ischemia was induced by clamping the left external and internal carotid arteries (ischemic rats), followed by 3-h recirculation. 31P magnetic resonance (MRS) spectroscopic studies revealed that severe intracellular acidosis occurred and ATP disappeared completely for a least the last 20 min of ischemia. Cerebral blood flow (CBF), measured by the hydrogen clearance technique, decreased to approximately 11% of the preischemic level in the frontal cortex soon after the induction of ischemia. On resuscitation, ATP recovered completely and the preischemic intracellular pH level was restored within 180 min. CBF has recovered to approximately 30% of the preischemic level at 5 min after resuscitation. The CBF recovery was not compete even at 180 min after resuscitation. With this model, the effects of pure ischemia without hypoxia on the neonatal brain and the process of recovery from transient ischemia can be studied.

Adenosine Triphosphate↗
PubMed1996

Synthesis and biological activity of four kinds of reversed peptides.

We have synthesized four kinds of reversed peptides of various physiologically active peptides, which inhibit TNF (tumor necrosis factor) cytotoxicity, produce NGF (nerve growth factor), exert antimicrobial activity and inhibit cell attachment, respectively. They were examined for their biological activity in comparison with that of normal peptides, that is, naturally occurring peptides. The reversed peptides induce similar activities, but to a lesser extent than those of the normal peptides, respectively. These results indicate that there may be conformationally ambiguous binding in some of the naturally occurring ligand-protein interactions. This method may be useful as a tool to rapidly generate a novel lead peptide with the desired biological function from a naturally occurring active peptide.

Amino Acid Sequence↗
PubMed1996

Protecting effect of a green tea percolate and its main constituents against gamma ray-induced scission of DNA.

Gamma ray-induced scission of puC18 plasmid DNA prepared from E. coli was examined in the presence of a green tea percolate and its main constituents, L-ascorbic acid (used as the sodium salt) and (-)-epigallocatechin gallate. Each of these showed a protecting effect against DNA scission. The relationship between the protecting effect against DNA scission and the scavenging effect of the hydroxyl radical was examined, and is discussed from the viewpoint of interaction with DNA.

Antimutagenic Agents↗
PubMed1996

Age associated changes in the distribution of lpr gene-induced B220-positive T cells in lymphoid organs of MRL/Mp-lpr/lpr mice using dual exposure microphotographs of double immunofluorescence staining.

Homozygous MRL/Mp-lpr/lpr [MRL/lpr] mice, which have an autosomal recessive mutant lpr gene and exhibit defects in Fas antigen, spontaneously develop autoimmune disease with progressive expansion and accumulation of characteristic abnormal CD4-CD8-double negative T cells that express B220 surface antigen, a B cell-specific surface marker in normal mice. We analyzed the distribution and age related changes of lpr gene-induced abnormal T cells (B220-positive lpr T cells) in the lymphoid organs of MRL/lpr mice. We studied cryostat sections of the spleen, peripheral lymph nodes, mesenteric lymph nodes, and Peyer's patches at different stages using FITC [fluorescein isothiocyanate)-conjugated monoclonal antibodies directed against B220 (RA3-6B2) and PE (phycoerythrin)-conjugated anti-mouse CD3 (2C11) monoclonal antibody, examining dual-exposure microphotographs of double-immunofluorescence stained preparations. We observed that in aged MRL/lpr mice, B220-positive abnormal lpr T cells were not present in the thymus-dependent area, and the majority of the follicular area cells were displaced by lpr T cells. These findings suggest that the cellular trafficking of B220-positive lpr T cells differs from that of conventional T cells and that these lpr-derived T cells play a role in the follicle.

Aging↗
PubMed1996

Expression of S-100 protein and glial fibrillary acidic protein in cultured submandibular gland epithelial cells and salivary gland tissues. Histogenetic implication for salivary gland tumors.

S-100 protein and glial fibrillary acidic protein (GFAP) were studied in human salivary gland tissues and human cultured submandibular gland epithelial cells. Immunohistochemically, ductal cells in normal salivary gland tissues were positive for S-100 protein and GFAP, but myoepithelial cells were uniformly negative. Immunocytochemically, cultured submandibular gland ductal cells were positive for S-100 protein and GFAP. By immunoblotting analysis of the cultured cell lysates, a 6.5-kd S-100 protein was detected. This band corresponded to S-100 protein purified from bovine brain. The cultured submandibular gland cells expressed 49- and 54-kd GFAP polypeptides. These results have important implications for the histogenesis of salivary gland tumors.

Animals↗
PubMed1996

[Perioperative management for partial resection of a lymphangioma of the tongue].

Twelve month old boy had been suffering from a neck lymphangioma. Partial resection was carried out in his newborn period at another hospital, and he was obliged to be tracheostomied because of severe airway obstruction due to postoperative edema. He was scheduled for partial glossectomy since his tongue had increased in mass, which could easily be injured by teeth, and he had difficulties in swallowing recently. His airway was not obstructive even during sleep and preoperative MRI showed adequate space around the larynx. We induced anesthesia by a mask and he was subseqently intubated with a fiberscope via his nose because his huge and less mobile tongue could not allow the insertion of a laryngoscope and this might cause bleeding. We did not extubate the endotracheal tube for fear of airway obstruction attributable to postoperative edema. Marked edema around the neck persisted longer than we expected. We tried to evaluate the degree of diminution of edema with MRI twice to decide when extubation could be attempted. However, examination with MRI could not give us useful informations. Consequently we evaluated the timing of extubation by examining whether he could close his mouth or not, whether his tongue could move freely and the degree of edema. We realized lymphangioma caused marked and extensive edema after the operation and we should keep in mind that lymphangioma of the tongue might cause various anesthetic problems especially on airways.

Anesthesia, Inhalation↗
PubMed1996

[Anesthetic management of 6 cases with dilated cardiomyopathy for non-cardiac surgery].

We report anesthetic management of 6 cases (5 patients) with dilated cardiomyopathy for noncardiac surgery. The severity of their cardiomyopathy evaluated by left ventricular ejection fraction (LVEF) utilizing echocardiography was different in each case. The management of anesthesia was divided into 3 steps according to the LVEF. In cases with LVEF over 0.45, it was possible to perform regular anesthetic management by carefully selecting and controlling anesthetic agents. In 2 cases with LVEF from 0.2 to 0.4, anesthetic management was difficult. Some vasoactive drugs (e.g. dopamine) and intensive monitoring devices (e.g. pulmonary artery catheter) were needed to optimize anesthetic course. In one case with LVEF less than 0.2, we discussed much about surgical indication. Because of the malignant nature of the tumor, we agreed to proceed. IABP was inserted preoperatively and this proved to be life-saving during the procedure. It is important to have an inter-departmental discussion on these severely compromised cases.

Adult↗
PubMed1996

[Cerebral hypoperfusion and leukomalacia].

Periventricular leukomalacia (PVL) is one of the neuropathological varieties of the neonatal hypoxic-ischemic encephalopathy. Recently we established a new canine model of PVL, by ligation of bilateral common, external and internal carotid arteries. In this paper we describe the relationship between neuropathological and neurological/behavioral findings of the PVL dogs.

Animals↗