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Biomedical subjects

H Ohta

Publications and source records attributed to H Ohta.

At least 379 records · Page 21Linked to original sources

Transpedicular fixation with Zielke instrumentation in the treatment of thoracolumbar and lumbar injuries.

STUDY DESIGN: Sixty-five patients who underwent transpedicular fixation for thoracolumbar and lumbar injuries were studied for type of injury, the severity of paralysis, the degree of postoperative correction, and instrumentation failures. OBJECTIVES: To evaluate the surgical approaches and the selection of instrumentation to determine indications for using the transpedicular fixation procedure. SUMMARY OF BACKGROUND DATA: Various transpedicular fixation devices have been used for different type of injuries, and satisfactory postoperative results were not obtained in some studies. METHODS: Forty patients had burst fractures, 19 had fracture dislocations, and six had chance-type fractures. An anterior decompression procedure was used for most cases of burst fracture and some cases of fracture dislocation where anterior compression factors were present. The Zielke or modified Zielke system was used as an internal fixator for posterior segmental fixation. RESULTS: No patient had neurologic deterioration after surgery. Twenty of 28 patients with incomplete lesions improved postoperatively according to Frankel grades. The instrumentation failed in only one patient, in whom a nonunion developed. CONCLUSION: With transpedicular fixation, it is possible to provide solid internal fixation that is circumscribed to the injured vertebral segments. The elasticity of the Zielke rod makes it an excellent transpedicular fixation device because it is easily attached and reduction is easily performed. Anterior decompression with fusion needs to be used with transpedicular fixation in the treatment of injuries (especially burst fractures).

Adult↗

Progressive cognitive impairment following chronic cerebral hypoperfusion induced by permanent occlusion of bilateral carotid arteries in rats.

The effects of chronic cerebral hypoperfusion induced by permanent occlusion of bilateral common carotid arteries (2VO) on learning and memory performance were examined in rats using an eight-arm radial maze task. The learning of the task was severely impaired in the permanent 2VO rats that had not been pretrained, while the retention was slightly impaired and soon recovered in the permanent 2VO rats that had been fully pretrained when tested within 1 month after the 2VO operation. The performance, however, was impaired in the pretrained rats when a 3-min delay was interposed between the fourth and fifth choices. Moreover, when retrained in the radial maze 4 months after the permanent 2VO, these same rats showed a performance impairment. Some loss of the hippocampal pyramidal neurons was observed 1 month after the permanent 2VO, although the decrease was not significant. However, significant loss of the cells was observed in the hippocampus CA1 subfield 4 months after the operation. We concluded that: (1) In the early stage (1 month after permanent 2VO), a learning deficit was observed in the non-pretrained rats. In the pretrained rats, working memory was not impaired, whereas longer term memory was compromised; (2) in the late stage (4 months after permanent 2VO), working memory may have also been impaired in the pretrained rats; and (3) this progressive cognitive deficit seemed to parallel the progress of neuronal damage.

Animals↗

Genetic diagnosis identifies occult lymph node metastases undetectable by the histopathological method.

The mutant allele-specific amplification (MASA) method is capable of detecting one tumor cell containing genetic changes in a sample containing thousands of normal cells. To investigate whether MASA can be applied to sensitive detection of lymph node metastasis, we screened 22 colorectal cancers for K-ras and p53 mutations and examined corresponding regional lymph node at the genetic level by the MASA method. Six of the primary tumors were found to certain K-ras mutations, and nine exhibited mutations of the p53 gene. In seven of the 14 cases in which genetic alterations were identified (mutations in both genes were found in one tumor), we found discrepancies between the genetic and the histopathological diagnoses with respect to the presence or absence of cancer cells in lymph nodes, in that these patients were histologically diagnosed lymph node negative, hn(-) but genetically diagnosed lymph node positive, gn(+). Because disease recurs in 20-30% of cancer patients whose lymph nodes are histopathologically negative after surgery, genetic evaluation of lymph nodes for metastasis may become a useful prognostic indicator.

Adult↗

Glycine elicits release of acetylcholine from the nucleus tractus solitarii in rat.

Previous studies have suggested that cardiovascular responses elicited by injection of glycine into the nucleus tractus solitarii (NTS) depend upon interactions between glycinergic and cholinergic neuronal elements in NTS. Release of acetylcholine in response to glycine is one such interaction that has been shown in slices of hippocampus and striatum. In this study we sought to test the hypothesis that glycine causes release of acetylcholine from neurotransmitter stores in NTS. We compared release from NTS with that from adjacent hypoglossal nucleus and from caudate nucleus. Release of radiolabeled acetylcholine was determined in vitro after incubating NTS with [3H]choline. Exposure of NTS and caudate nucleus, but not hypoglossal nucleus, to glycine caused release of acetylcholine in a calcium-dependent manner that varied with concentration of glycine in the incubation medium. The maximally effective concentration (1 mM) of glycine elicited 136% increases over basal levels. Glycine did not elicit release of [3H]acetylcholine from tissue when calcium ion had been removed from the bath. Acetylcholine also was not released if tissue was incubated with either strychnine (10 microM) or hemicholinium-3 (1 mM) prior to exposure to glycine (1 mM). Thus, glycine, acting at strychnine-sensitive receptors in NTS, elicits release of acetylcholine from a portion of locally synthesized neurotransmitter stores.

Acetylcholine↗

Frequent replication errors at microsatellite loci in tumors of patients with multiple primary cancers.

Nearly 10% of cancer patients develop a second primary cancer within 10 years after surgical removal of the first tumor. Hence, detection of a genetic risk for developing multiple primary tumors would be of clinical importance. To investigate whether a genetic defect(s) involving the mismatch repair system constitutes an important risk factor in patients with multiple primary cancers, we examined replication errors (RER) at microsatellite loci in 79 primary cancers which had developed among 38 patients with multiple primary cancers. The RER(+) phenotype was observed at five microsatellite loci on chromosomes 2, 3, 11, or 17 in tumors from 34 (89%) of 38 patients with multiple primary cancers but only in 19 tumors from 174 patients (11%) with a single primary cancer. Our results suggested that: (a) genetic instability may play an important role in development of multiple primary cancers, and (b) testing for RER in a primary cancer may be an appropriate approach to detection of patients at high risk for developing multiple primary cancers.

DNA Repair↗

Molecular and biological characterization of fusion regulatory proteins (FRPs): anti-FRP mAbs induced HIV-mediated cell fusion via an integrin system.

Anti-FRP mAbs induced polykaryocyte formation of U2ME-7 cells (CD4+U937 cells transfected with the HIV gp160 gene). Anti-FRP-1 mAb immunoprecipitated gp80-85, gp120 and homodimers of these peptides, and anti-FRP-2 mAb reacted with gp135 identically to the alpha 3 subunit of integrin. Both anti-FRP-1 and anti-FRP-2 mAb-induced cell fusion was blocked by anti-beta 1 integrin antibody, fibronectin or inhibiting anti-FRP-1 antibody. Therefore, anti-FRP mAbs were thought to induce the fusion via an integrin system(s). FRP-mediated fusion was temperature, cytoskeleton, energy and Ca2+ dependent. These experiments showed a possible regulatory function of cell fusion by an integrin system(s).

Amino Acid Sequence↗

A novel lipoxygenase from rice. Primary structure and specific expression upon incompatible infection with rice blast fungus.

A novel lipoxygenase cDNA (3,007 base pairs) was isolated from rice leaves (Oryza sativa cv. Aichiasahi) which had been infected with an incompatible race of the rice blast fungus, Magnaporthe grisea. A single copy of the gene is present in the rice genome and encodes a protein of 923 residues with a molecular weight of 102,714. This gene product shares the least amino acid sequence homology among plant lipoxygenases identified to date. A novel feature of this gene product is a putative transit peptide sequence at the amino terminus, suggesting the enzyme is localized in chloroplasts. An active lipoxygenase was expressed from the cDNA in Escherichia coli and characterized. The lipoxygenase introduces molecular oxygen exclusively into the C-13 position of linoleic and linolenic acids. The gene is expressed at high levels 15 h after inoculation with an incompatible race of M. grisea, at a low level after inoculation with a compatible race of the pathogen, and is not expressed in mock-infected leaves. Gene expression begins at the same time that the pathogen begins to penetrate into leaf tissue. This novel lipoxygenase gene expression is a part of the early response of the host to pathogenic attack.

Amino Acid Sequence↗

An adult case of Bland-White-Garland syndrome with collaterals from the bronchial artery.

We report herein an adult case of anomalous origin of the left coronary artery from the pulmonary artery (Bland-White-Garland syndrome; BWG syndrome). The patient had chest discomfort during exercise and signs of mitral regurgitation. We diagnosed him as having BWG syndrome by angiography, and performed surgical treatment. At the operation, retrograde coronary blood flow was found through the left coronary artery during aortic cross-clamping. This suggested extracardiac anastomosis from peripheral arteries to the left coronary artery. Since the collateral blood flow was considerable during aortic cross-clamping, only the left coronary artery was closed. A collateral from the left bronchial artery to the left circumflex artery was demonstrated by postoperative angiography. Cases of adults with BWG syndrome are rare, and this may be the first report of a collateral from the bronchial artery.

Adult↗

Release of bile canalicular membrane antigen into blood in experimental extrahepatic cholestasis of the rat.

The level of a bile canalicular membrane antigen in serum during extrahepatic cholestasis was serially analyzed using HAM.4, a monoclonal antibody against a bile canalicular membrane glycoprotein of normal rat hepatocytes. After bile duct ligation, the level of HAM.4 antigen in serum promptly increased within 1 hr, reached a maximum at 3 hr, and declined somewhat until 48 hr, where it plateaued. Elevated levels of HAM.4 antigen in serum preceded those of well-known biliary marker enzymes activities. Immunohistochemical studies showed that the expression of HAM.4 antigen in hepatocytes and bile duct cells was not altered appreciably after bile duct ligation even when HAM.4 antigen in serum reached a maximal level. The serum and hepatic HAM.4 antigen had a molecular weight of 110 kDa. These results suggest that HAM.4 antigen may be regarded as a potential marker of the early stage of cholestasis, with release occurring before apparent histological changes.

Animals↗

Serum levels of c-erbB-2 protein in digestive diseases.

The clinical significance of the measurement of c-erbB-2 oncogene product was evaluated. The subjects consisted of 404 patients, including 248 with cancer of the digestive organs and 128 with benign digestive diseases. Serum c-erbB-2 protein levels were measured by sandwich immunoenzyme assay. The positive rates of c-erbB-2 protein, at a cut-off value of 17.0 U/ml, were, for cancers: hepatocellular carcinoma 61.6%, biliary tract cancer 54.8%, pancreatic cancer 25.0%, esophageal cancer 33.3%, gastric cancer 16.9%, and colorectal cancer 5.0%. For benign digestive diseases, the rates were: liver cirrhosis 63.3%, chronic hepatitis 43.2%, acute hepatitis 42.9%, other liver diseases 42.8%, cholelithiasis 30.0%, and chronic pancreatitis 0%. Serum c-erbB-2 protein levels were significantly correlated with the markers of hepatic functional reserve, the indocyanine green retention rate and the hepaplastin test. These findings suggest that serum c-erbB-2 protein levels are greatly influenced by liver dysfunction and that their clinical usefulness as a serum tumor marker is questionable.

Adult↗

Measurement of sialylated stage-specific embryonic antigen-1 in pure pancreatic juice for the diagnosis of pancreatic cancer.

The diagnostic significance of measuring sialylated stage-specific embryonic antigen-1 (SLX) in pure pancreatic juice was evaluated in 20 patients with pancreatic cancer, 43 with chronic pancreatitis, 13 with cholecystolithiasis, and 15 control individuals. Four fractions of pure pancreatic juice were collected sequentially from the pancreatic duct by endoscopic cannulation. The SLX levels in all four fractions of pure pancreatic juice were significantly higher in patients with pancreatic cancer than in controls. On the other hand, patients with chronic pancreatitis or cholecystolithiasis did not have SLX levels that significantly differed from those of controls in any fraction. When the cut-off value was set as the mean concentration +2 times the standard deviation of the control values, the positive rates of SLX in the first fraction (washout phase) and the third fraction (secretory phase) of pure pancreatic juice from pancreatic cancer were 55% (11/20) and 40% (8/20), respectively. Although the false positive rates in the first fraction were high in chronic pancreatitis (30%) and cholecystolithiasis (31%), such high SLX levels in the third fraction were found only in one (2%) patient with chronic pancreatitis and in one (8%) with cholecystolithiasis. The specificities of the test for pancreatic cancer in the first fraction and the third fraction were 70% (39/56) and 96% (54/56), respectively. These results indicate that the measurement of SLX in the third fraction of pure pancreatic juice is useful as a specific marker for pancreatic cancer.

Chronic Disease↗

Beta 2- but not beta 1-adrenoceptors are involved in desipramine enhancement of aggressive behavior in long-term isolated mice.

The effects of several beta-adrenoceptor antagonists on the desipramine-induced increase in aggressive behavior in long-term isolated mice were examined. Desipramine HCl (10 mg/kg, IP) significantly increased the duration of aggressive behavior in isolated mice but did not significantly change the latency to the first attack consistent with our previous reports. Intraperitoneal administration of (+/- )propranolol HCl (2.5-10 mg/kg), a nonselective beta-adrenoceptor antagonist, dose dependently attenuated the desipramine-induced enhancement of aggressive behavior without significantly affecting the basal aggressive responses. ICI118,551 HCl (1.25-5 mg/kg, IP), a selective beta 2-adrenoceptor antagonist, also blocked the desipramine-induced enhancement of aggressive behavior in a dose-dependent manner, whereas metoprolol tartrate (5-20 mg/kg, IP), a selective beta 1-adrenoceptor antagonist, did not affect it. Moreover, clenbuterol HCl (0.1-0.5 mg/kg, IP), a lipophilic beta 2-adrenoceptor agonist, significantly increased the duration of basal aggressive behavior. Taken together with our previous finding that the desipramine-induced enhancement of aggressive behavior can be blocked by yohimbine, an alpha 2-adrenoceptor antagonist, the present results indicate that not only alpha 2- but also beta 2-adrenoceptor stimulation plays important roles in modulation of aggressive behavior in long-term isolated mice.

Aggression↗

Monoamine depletion attenuates the REM sleep deprivation-induced increase in clonidine response in the forced swimming test.

Effect of monoamine depletion on the REM sleep (REMs) deprivation-induced increase in clonidine response in the forced swimming test was investigated. Mice were deprived of REMs by the small pedestal method. Clonidine HCl (10-1000 micrograms/kg, IP), an alpha 2-adrenoceptor agonist, dose dependently increased swimming activities in group-housed and socially isolated mice used as the control groups. The dose-response relationship shifted to the left following REMs deprivation (ED50 values in the group-housed, isolated, and REMs-deprived mice were 250, 200, and 27 micrograms/kg, respectively). Monoamine depletion, induced by reserpine (5 mg/kg, IP) plus alpha-methyl-p-tyrosine (250 mg/kg, IP), did not produce any changes in the effects of clonidine in the control groups. However, in REMs-deprived mice, monoamine depletion significantly decreased the effect of 100 micrograms/kg clonidine, but not that of 300 micrograms/kg clonidine on swimming activity. These results indicate that clonidine-induced increase in swimming activity in the forced swimming test is mainly mediated by postsynaptic alpha 2-adrenoceptor, and that endogenous noradrenaline in the brain plays an important role in the increase of clonidine response following REMs deprivation treatment. The neuronal mechanism of the increase in clonidine response is discussed.

Adrenergic alpha-2 Receptor Antagonists↗

Paeoniflorin attenuates learning impairment of aged rats in operant brightness discrimination task.

The effects of paeoniflorin isolated from peony were examined on an aging-induced learning deficit in an operant brightness discrimination task in Fischer 344 rats. Learning in aged (25 months) rats was significantly impaired compared with young (5 months) rats. Daily administration of paeoniflorin (0.01 mg/kg, PO) significantly attenuated the learning impairment in aged rats, whereas it did not affect the learning in young rats. Although tacrine (0.3 and 1 mg/kg, IP), a cholinesterase inhibitor, also did not affect the learning in young rats, it slightly augmented the aging-induced learning deficit in the present task. These data indicate the therapeutic potential of paeoniflorin in the treatment of senile dementia and aging-induced cognitive dysfunction.

Aging↗

Involvement of dopamine D2 receptor mechanism in the REM sleep deprivation-induced increase in swimming activity in the forced swimming test.

Effects of monoamine synthesis inhibitors and dopamine antagonists on rapid eye movement sleep (REMs) deprivation treatment-induced increase in swimming activity were examined. Mice were deprived of REMs for 48 h by a small pedestal method. Swimming activity in REMs-deprived mice was significantly higher than those in group-housed or socially isolated animals used as the control. dl-alpha-Methyl- p-tyrosine methyl ester HCl (250 mg/kg, IP) decreased the swimming activity in REMs-deprived mice, whereas neither disulfiram (400 mg/kg, SC), a noradrenaline synthesis inhibitor, nor dl-p-chlorophenylalanine methyl ester HCl (300 mg/kg, IP) changed it. (+)-SCH23390 HCl (30 and 100 micrograms/kg, IP), a selective dopamine D1 antagonist, did not affect the activity in REMs-deprived mice. (+/-)-Sulpiride (12.5 and 25 mg/kg, IP), a selective dopamine D2 antagonist, dose-dependently decreased swimming activity in REMs-deprived mice, while it did not significantly change the swimming activity in the control animals. These results suggest that REMs deprivation treatment-induced increase in swimming activity is mainly due to the functional changes in the dopaminergic system rather than the noradrenergic or serotonergic system, and that dopamine D2 but not D1 receptor mechanism is involved in the increase in swimming activity in REMs-deprived animals.

Animals↗

Deviate P200 and P300 in non-patient college students with high scores on the schizophrenia scale of the Minnesota Multiphasic Personality Inventory (MMPI).

Event-related potentials (ERPs) were examined in 16 college students who had high scores on the Schizophrenia Scale of the MMPI (HSS) but were without a hereditary disposition for major psychiatric disorders. 32 sex- and age-matched college students were used as controls. Subjects whose T scores were higher than 70 were designated the HSS subjects. ERPs were recorded during an auditory oddball task. Although neither the P300 latencies nor the P200 latencies differed between the two subject groups, the amplitudes of P300 to rare stimuli and P200 to frequent stimuli were lower in the HSS subjects than in the controls. These results suggest that deficits, both in the P300-related cognitive function to rare relevant stimuli, as well as matching and/or the comparison process for irrelevant frequent stimuli, may be present in HSS subjects. The HSS subjects, especially those with a combination of P300 and P200 deficits, even though without a hereditary diathesis for schizophrenia, may constitute one type of high-risk group.

Adolescent↗

Internalization of human extracellular-superoxide dismutase by bovine aortic endothelial cells.

The high heparin-affinity subtype C of the secretory enzyme extracellular-superoxide dismutase (EC-SOD) mainly exists on the outside of endothelial cell surface in the vasculature. Radioiodinated recombinant EC-SOD C(r-EC-SOD C) bound to cultured bovine aortic endothelial cells (BAE cells) at 4 degrees C with an association constant of 9.35 x 10(6) M-1 and maximum binding of 600 ng/dish (3109 ng/mg cellular protein). When incubated at 37 degrees C for 1 h, some 125I-r-EC-SOD C was no longer releasable by heparin treatment, suggesting that 125I-r-EC-SOD C was internalized by BAE cells. Since the internalization was inhibited in the presence of heparin in medium, this step was mediated by the binding to cell surface heparin sulfate proteoglycans. When cells containing internalized 125I-r-EC-SOD C were incubated in newly added medium at 37 degrees C for up to 1 h, 54% of radioactivity was recovered in new medium. However, 71% of the radioactive materials released to the medium, presumably 125I-r-EC-SOD C and its metabolic products, had lost heparin binding activity. Much of internalized 125I-r-EC-SOD C was degraded to low molecular weight peptides, because 54% of the radioactive products released to the medium were trichloroacetic acid-soluble and 59% of them were below 10 kDa. About one-fourth of radioactive materials were recycled 125I-r-EC-SOD judged from heparin-HPLC and Sephacryl S-200 column chromatography. In the presence of chloroquine, lysosomal protease inhibitor, the release of internalized 125I-r-EC-SOD C decreased to 59% compared with the control culture.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗