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Biomedical subjects

T Kondoh

Publications and source records attributed to T Kondoh.

At least 73 records · Page 4Linked to original sources
PubMed2000

Magnetic resonance imaging and histologic evidence of postoperative back muscle injury in rats.

STUDY DESIGN: Postoperative back muscle injury was evaluated in rats by magnetic resonance imaging and histologic analyses. OBJECTIVE: To compare the magnetic resonance imaging manifestation of back muscle injury with the histologic findings in rats and to subsequently clarify the histopathologic appearance of the high intensity regions on T2-weighted images in human postoperative back muscles. SUMMARY OF BACKGROUND DATA: In a previous study, it was found that the signal intensity on T2-weighted images of the postoperative back muscles was increased in patients who had postsurgical lumbar muscle impairment, especially in those with a prolonged surgery duration. However, the specific histopathologic changes that cause the high signal intensity on T2-weighted images remain unclear. METHODS: Rats were divided into three groups: sham operation group, 1-hour retraction group, and 2-hour retraction group. Magnetic resonance imaging and histology of the multifidus muscles were examined before surgery and at 2, 7, and 21 days after surgery. RESULTS: T2-weighted imaging was more useful than T1-weighted imaging to estimate back muscle injury. The high signal intensity of the multifidus muscles on T2-weighted images remained 21 days after surgery only in the 2-hour retraction group. Histologically, the regeneration of the multifidus muscles was complete at 21 days after surgery in the 1-hour retraction group, but the regenerated muscle fibers in the 2-hour retraction group had a small diameter, and the extracellular fluid space remained large. CONCLUSION: The high signal intensity on T2-weighted images of the postoperative multifidus muscles in the regenerative phase may be due to an increased extracellular space and incomplete muscle fiber regeneration.

Animals↗
PubMed2000

Blood-brain barrier formation of grafted human umbilical vein endothelial cells in athymic mouse brain.

Human umbilical vein endothelial cells (HUVECs) were transplanted in athymic mouse brain and neovascularization of grafted endothelial cells was studied. HUVECs were transfected by a reporter gene pEGFPE-N1 in vitro and grafted stereotactically in unilateral striatum of adult nude mice. Histological studies in 4 weeks revealed that grafted HUVECs newly formed microvessels in brain, which were migrated and fused with host vessels. Intravenous injection of Evans blue before sacrificing animals resulted in no extravasation of dye, indicating that a blood-brain barrier (BBB) was formed by the grafted HUVECs. Immunohistochemistry demonstrated that host astrocytes extended glial feet on the grafted endothelial cells and a part of the newly formed vessels was positive with glucose transporter-1. These results indicate that endothelial cells from an ectopic origin have the potential to form a BBB after grafting in the central nervous system.

Animals↗
PubMed2000

Magnetic resonance imaging findings and clinical symptoms in the temporomandibular joint in patients with mandibular continuity defects.

PURPOSE: This study explored the morphologic changes and clinical symptoms related to the temporomandibular joint (TMJ) associated with long-term lack of mandibular continuity. PATIENTS AND METHODS: The subjects were 20 patients (40 TMJs) who underwent mandibulectomy including the condyle or segmental mandibulectomy without mandibular reconstruction more than 6 months previous to the study. The 40 TMJs were classified into the following 3 groups: group I: TMJs with a major mandibular fragment including the mandibular body (n = 21), group II: TMJs with a minor mandibular fragment including only the condylar process or the mandibular ramus (n = 10), and group III: TMJs without a condyle (n = 9). All TMJs were examined with respect to disc position, condylar position, bony changes, and appearance of joint effusion on magnetic resonance imaging, as well as for the presence of joint or muscle pain and joint noise. RESULTS: The rate of anterior disc displacement was 28.6% in group I, 10.0% in group II, and 100% in group III. All condyles in group I were located in the glenoid fossa. Seven of 10 condyles in group II were dislocated anteriorly out of the glenoid fossa. However, these condyles were situated in the intermediate zone of the disc. Osteoarthritic changes was found in 1 joint in group II. Joint effusion was not observed in group I. However, joint effusion was detected in the posterior region of the upper joint compartment in 7 of 10 TMJs in group H and in 8 of 9 TMJs in group III. In group II, the 7 TMJs with joint effusion were the same joints with anteriorly dislocated condyles. Clinical symptoms of TMJ pain, TMJ noise, or muscular pain were not found in any patients. CONCLUSIONS: Partial mandibulectomy does not affect the relationship between the disc and the condyle or the bony condition of the TMJ. The disc without a condyle will become anteriorly displaced with time. The condyle not connected to the mandibular body often dislocates anteriorly out of the glenoid fossa, while retaining a normal relationship with the disc. Joint effusion, which is detected in nonfunctional TMJs, is not associated with an inflammatory reaction in the joint compartment.

Humans↗
PubMed2000

Complications of temporomandibular joint arthroscopy: a retrospective analysis of 301 lysis and lavage procedures performed using the triangulation technique.

PURPOSE: This study evaluated the complications of temporomandibular joint (TMJ) arthroscopic lysis and lavage performed using the triangulation technique. PATIENTS AND METHODS: The 202 consecutive patients (301 joints) who underwent arthroscopic lysis and lavage between 1992 and 1995 were retrospectively surveyed. The preoperative diagnosis of all patients was anterior disc displacement without reduction. RESULTS: Complications were observed in 31 (10.3%) of 301 cases of arthroscopic lysis and lavage. Of these, otologic complications were found in 26 cases (8.6%): blood clots in the external auditory canal in 9; laceration of external auditory canal in 7; partial hearing loss in 5; ear fullness in 2; vertigo in 1; and perforation of tympanic membrane with laceration of external auditory canal in 1. Neurologic injuries were found in 5 cases (1.7%): fifth cranial nerve injuries in 3; and seventh cranial nerve injuries in 2. No other complications were observed. CONCLUSIONS: A high level of understanding of the regional anatomy helps reduce the complications associated with arthroscopic lysis and lavage in the TMJ.

Adolescent↗
PubMed2000

Seizure control after radiosurgery on cerebral arteriovenous malformations.

Among 462 cases of cerebral arteriovenous malformation (AVM) treated with gamma-radiosurgery, the initial presentations were haemorrhage in 68%, epilepsy in 12.8%, neurological deficits in 3.2%, minor symptoms in 7.6% and asymptomatic in 4.5% respectively. There were 79 cases (17.1%) who had had a convulsive seizure before radiosurgery and they were classified into two groups: 58 cases presented with seizure as an initial symptoms (group A) and the other 21 cases mostly had seizures following intracranial haemorrhage (group B). Before radiosurgery, generalised seizure was the predominant seizure pattern in both groups, followed by pure partial and complex partial seizures. There was no major difference in seizure patterns or seizure frequency in group A and B. At radiosurgery AVMs were treated with a mean maximum dose of 37.2 Gy and a marginal dose of 19.8 Gy. Seizures had apparently decreased in most of the cases at the last follow-up (mean 24 months) according to the obliteration of the nidus. Seizures were either decreased or had disappeared in 91.6% of group A and 62.5% of group B patients. The overall results indicate that seizures improved in 85.5%, were changed in 11.6% and deteriorated in 2.9% of patients. Radiosurgery is effective not only for the obliteration of nidus of cerebral AVM, but also for seizure control, even before complete occlusion of the nidus.

Adult↗
PubMed2000

Improvement of C-reactive protein levels and body temperature of an elderly patient infected with Pseudomonas aeruginosa on treatment with Mao-bushi-saishin-to.

OBJECTIVE: To examine the effectiveness of Mao-bushi-saishin-to (Ma-Huang-Fu-Zi-Xi-Xin-Tang in Chinese medicine) (Tochimototenkaido Co. Ltd., Osaka, Japan), one of the traditional herbal medicines, against resistant bacterial infection. SETTING: The Nursing Center Himawari, Izumo, Japan DESIGN, PATIENT, AND PREPARATION: Half of the standard dose of Mao-bushi-saishin-to was prescribed for 7 days to one elderly patient with fever and positive C-reactive protein (CRP) levels suffering from drug resistant Pseudomonas aeruginosa. The daily standard dose of Mao-bushi-saishin-to is prepared from 1200 mg of dried extract obtained from three crude drugs, Ephedrae Herba (4 g), Asiasari Radix (3 g), and Aconiti Tuber (1 g). It is certified by the Japanese Ministry of Health and Welfare. RESULTS: The patient's fever and CRP level returned to normal levels. CONCLUSIONS: In cases in which the fever does not fall in response to antibiotics for at least 3 days, half of the standard dose of Mao-bushi-saishin-to for 7 days might be worth trying to induce remission, especially for elder patients.

Aged↗
PubMed2000

Hypothalamic and amygdalar neuronal responses to various tastant solutions during ingestive behavior in rats.

The forebrain, including the amygdala (AM) and hypothalamus, may be a higher brain center that modulates the activity of a brainstem neural system that influences ingestive behavior via descending projections. In this study, to elucidate the characteristics of sensory information processing in the forebrain in relation to this putative connection, we recorded neuronal activity in the AM and hypothalamus [lateral hypothalamic area (LHA), medial hypothalamic area (MHA)] of rats during discrimination of conditioned sensory stimuli and the ingestion of various tastant solutions. Of 420 responsive AM neurons identified, 24 were taste responsive and located mainly in the central nucleus of the AM. Multivariate analyses of these taste neurons suggested that in the AM, taste quality is processed on the basis of palatability. In the hypothalamus, of 282 LHA and MHA neurons recorded, 144 responded to one or more conditioned auditory stimuli and/or licking of one or more solutions. Stress, which is known to influence feeding behavior, increased the mean spontaneous activity of LHA neurons but decreased the mean spontaneous neuronal activity of MHA neurons. This pattern of changes in spontaneous neuronal activity correlated with alterations in feeding behavior during stress. Furthermore, the activity of both AM and LHA neurons was modulated flexibly during conditioned associative learning. Together, the data suggest that the activity of the AM and hypothalamic neurons is altered when animals must modulate ingestive behavior by learning a new stimulus associated with food and by being exposed to stress, suggesting that these forebrain areas are important modulators of the activity of a basic neural system in the brainstem that influences ingestive behavior.

Acoustic Stimulation↗
PubMed2000

Mechanisms of umami taste preference and aversion in rats.

The influence of glutamate intake on growth and appetite, and the mechanisms of preference and aversion for monosodium L-glutamate (MSG) solutions were investigated in rats. Food intake, but not weight gain, was reduced significantly in rats fed a glutamate + glutamine (Glx)-deficient diet compared with those fed a control diet. Increase in the voluntary intake of Glx solutions was more rapid in rats fed the Glx-deficient diet. The preference and aversion for MSG solutions were distinctly different in 14 rat strains tested. Brown-Norway rats showed a strong preference for 60 mmol/L MSG and did not show aversive behavior toward solutions containing up to 600 mmol/L MSG. Sprague-Dawley (SD) rats showed a moderate preference for 60 mmol/L MSG and a weak aversion for MSG concentrations higher than 240 mmol/L; Long-Evans Agouti rats showed a moderate preference for 60 mmol/L MSG and a marked aversion for MSG concentrations higher than 120 mmol/L. Aversion was not due to nonspecific hyperosmotic effects. After section of gastric branches of the vagus nerve, MSG became aversive to SD rats. Aversion to 240 mmol/L MSG was reduced by 23-39% when combined with proline, alanine, glycine and glucose. These results show that the preference and aversion for MSG are determined by genetic factors, as well as vagus nerve function, and that the aversion to high MSG concentrations is reduced by the presence of other glucogenic amino acids and sugars.

Amino Acids↗
PubMed2000

Presynaptic nicotinic acetylcholine receptors as a functional target of nefiracetam in inducing a long-lasting facilitation of hippocampal neurotransmission.

Nefiracetam (1-10 microM), a nootropic (or cognition-enhancing) agent, persistently potentiated currents through Torpedo acetylcholine (ACh) receptors expressed in Xenopus oocytes as a result of interacting with a protein kinase C pathway and the ensuing protein kinase C phosphorylation of the receptors. A similar effect was found in neuronal nicotinic ACh receptors (alpha4beta2 and alpha7). In contrast, the other nootropic agents such as piracetam and aniracetam had no potentiating action on the receptors. A sustained enhancement in the activity of nicotinic ACh receptors induced by nefiracetam caused a marked increase in the glutamate release, leading to a long-term potentiation-like facilitation of hippocampal synaptic transmissions. One of the consistent neuropathologic features of the Alzheimer brain is a loss of nicotinic ACh receptors. This fact, together with the results of our study, raises the possibility that the loss of nicotinic ACh receptors may be a key factor in the decline of cognitive function observed in Alzheimer disease and that agents targeting neuronal nicotinic ACh receptors like nefiracetam could, therefore, be of great therapeutic importance.

Acetylcholine↗
PubMed2000

Effects of repeated cold stress on activity of hypothalamic neurons in rats during performance of operant licking task.

The present study investigated the effects of repeated cold stress on single neuron activity in the lateral hypothalamic area (LHA) and medial hypothalamic area (MHA) of behaving rats. The rats were trained to lick a protruding spout in response to one of several cue-tone stimuli (CTSs) to ingest water, or amino acid, NaCl or glucose solution. Following this training, the rats were raised under either stressed (repeated temperature changes between -3 and 24 degrees C) or control (24 degrees C) condition for 2 mo. During this period, neuronal activity was recorded in the LHA and MHA. For rats raised under the stressed condition, mean spontaneous firing rate of LHA neurons was significantly greater than for rats under the control condition. More LHA neurons in the stressed rats responded, with an accompanying decrease in activity (inhibitory response), to CTSs than in the control rats. During extinction learning, some LHA neurons enhanced or reversed the responses to CTSs in the stressed rats, whereas no LHA neurons showed such response changes in the control rats. In contrast to the effects of the stressed condition on LHA neuron activity, mean spontaneous firing rate of MHA neurons in the stressed rats was significantly smaller than in the control rats. Fewer MHA neurons in the stressed rats responded to CTSs and/or ingestion of sapid solutions. The preceding results suggested that repeated cold stress produces a specific pattern of changes in spontaneous activity and responses to sensory stimuli in LHA and MHA neurons; this could underlie the behavioral changes induced by repeated cold stress such as hyperphagia and hyper-reactivity to sensory stimuli.

Acoustic Stimulation↗
PubMed2000

Prognostic significance of electrocardiographic change during anginal attack in patients with unstable angina.

OBJECTIVE AND METHODS: We examined the prognostic significance of electrocardiographic change during anginal attack, C-reactive protein and fibrinogen in 169 patients with unstable angina. RESULTS: During the 90-day follow-up period, 26 patients (15%) exhibited new cardiac events (death, myocardial infarction or urgent revascularization). Using multivariate analysis, ST depression (relative risk 7.507 [95 % confidence intervals 1.842-30.592], p<0.01) during anginal attack was found to be an independent risk factor to predict cardiac events as well as diabetes mellitus, an increased total cholesterol level and the use of a thrombolytic agent. C-reactive protein and fibrinogen did not have prognostic significance. CONCLUSION: ST depression during anginal attack is an independent risk predictor for new cardiac events in patients with unstable angina.

Aged↗
PubMed2000

In vivo gene transfer into the periventricular region by electroporation.

Gene transfer by electroporation was attempted in the normal rat brain. The reporter gene pEGFP-C1 (25 micrograms/5 microliters) was injected into the striatum of young adult rats and various square electrical impulses were applied using a pair of electrodes implanted in the striatum. The brains were removed and sliced after 5 days. Histological examination revealed that the high energy impulses caused extensive tissue damage whereas lower energy impulses (200-400 mJ) resulted in the transfection of more than 300 cells per brain, which were widely distributed in the subependymal region of the lateral ventricle and extended long processes into the striatum.

Animals↗