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Biomedical subjects

K Iwanaga

Publications and source records attributed to K Iwanaga.

At least 37 records · Page 2Linked to original sources
PubMed2000

The effect of mental loads on muscle tension, blood pressure and blink rate.

Surface electromyogram (EMG), blood pressure (BP), blink rate (BR) and heart rate (HR) were recorded before and during 4 types of mental task. The mental task involved 3 tasks that encompassed the memory (M), visual search (VS) and color-word (CW) tasks besides the control task (CT) of maintaining a similar posture while focusing on a single spot on the computer screen. Except for CW, any voluntary movement for response to visual stimuli given were not demanded. Slightly but significant increases in integrated EMG (iEMG) were shown in terapezius, biceps and gastrocnemius muscles during tasks except for CT. Especially in the trapezius muscle during M, the most remarkable enhancements of iEMG and BP were shown. In VS and CW tasks, significant decreases in BR were observed, although in M and CT tasks there were no significant changes in it. There were no significant changes in HR in any type of tasks. The present study demonstrated the increase in muscle tension due to mental needs of cognitive tasks per se accompanying changes in BP and BR. And, enhancement of these physiological responses by memory loads and eyeball movement was discussed as a possible mechanism.

Adult↗
PubMed2000

Effects of inhalation of essential oils on EEG activity and sensory evaluation.

The purpose of this study was to investigate EEG changes in subjects directly after inhalation of essential oils, and subsequently, to observe any effect on subjective evaluations. EEG and sensory evaluation were assessed in 13 healthy female subjects in four odor conditions. Four odor conditions (including lavender, chamomile, sandalwood and eugenol) were applied respectively for each subject in the experiment. The results were as follows. 1) Four basic factors were extracted from 22 adjective pairs by factor analysis of the sensory evaluation. The first factor was "comfortable feeling", the second "cheerful feeling", the third "natural feeling" and the fourth "feminine feeling". In the score of the first factor (comfortable feeling), the odors in order of high contribution are lavender, eugenol, chamomile and sandalwood. 2) Alpha 1 (8-10 Hz) of EEG at parietal and posterior temporal regions significantly decreased soon after the onset of inhalation of lavender oil (p < 0.01). Significant changes of alpha 1 were also observed after inhalation of eugenol or chamomile. The change after inhalation of sandalwood was not significant. These results showed that alpha 1 activity significantly decreased under odor conditions in which subjects felt comfortable, and showed no significant change under odor conditions in which subjects felt uncomfortable. These results suggest a possible correlation between alpha 1 activity and subjective evaluation.

Administration, Inhalation↗
PubMed2000

Development and evaluation of the measurement system for the human shoulder joint based on the 6 DOF kinematic modelling.

Although numerical models on the shoulder complex joint are currently available, many are impractical because of the procedural complexity coupled with limited and mere simple simulations. The present study defined the clavicle-scapula system as the "base of the humerus" in determining the position of proximal head of humerus, rendering conclusive innovation of a six degree of freedom (DOF) shoulder complex joint model. Furthermore, a complete measurement system where evaluation by calibrating the actual values via the use of an electromagnetic tracking device (ETD) was developed based on the innovated model. The special calibration method using optimizing calculation to work out the rotational center of humerus was employed and actually tested if the theoretical consideration was practically available. As a result of accuracy check experiments, the measurement error was defined within 2-3 mm, indicating sufficient accuracy in studies for human movement. Our findings strongly advocate that the benefit of this novel measurement system would contribute to studies related to shoulder movements in physiological anthropology.

Biomechanical Phenomena↗
PubMed2000

Effects of specific warm-up at various intensities on energy metabolism during subsequent exercise.

BACKGROUND: To investigate the effects of specific warm-up at various intensities on energy metabolism during subsequent intense exercise. METHODS EXPERIMENTAL DESIGN: specific warm-up was consisted of 3 sets of wrist flexions for 5 min, with each set followed by a 3-min rest. The intensity of specific warm-up was set at 20%, 30% or 40% of maximal voluntary contraction (MVC). The subjects then performed a set of wrist flexions at 60% MVC for 4 min as the criterion exercise. For the control experiment, criterion exercise was done without specific warm-up. PARTICIPANTS: Five healthy volunteers. MEASUREMENTS: using phosphorus-31 magnetic resonance spectroscopy, spectra were obtained from the wrist flexor muscles to determine the ratio of inorganic phosphate to phosphocreatine (Pi/PCr) and intracellular pH. RESULTS: The Pi/PCr during the criterion exercise after specific warm-up at any intensity was not significantly different from that without specific warm-up. The intracellular pH during the criterion exercise after specific warm-up at 30% or 40% MVC was significantly higher than that without specific warm-up. CONCLUSIONS: These results indicate that mild warm-up exercise could inhibit the development of intracellular acidosis during subsequent intense exercise.

Adult↗
PubMed1999

Lewy body-type degeneration in cardiac plexus in Parkinson's and incidental Lewy body diseases.

Heart tissues of patients with PD or incidental Lewy body (LB) disease (ILBD) were examined by light and electron microscopy. LBs and alpha-synuclein-positive neurites were identified in the hearts from 9 of 11 patients with PD and from 7 of 7 patients with ILBD. LBs were present in both tyrosine hydroxylase-positive and -negative nerve processes, which are nerves of extrinsic sympathetic and intrinsic origin, respectively. These findings provide histologic evidence that the postganglionic sympathetic and intrinsic neurons in the heart are involved in the PD disease process.

Aged↗
PubMed1999

Application of surface-coated liposomes for oral delivery of peptide: effects of coating the liposome's surface on the GI transit of insulin.

We prepared two kinds of surface-coated liposomes and investigated their potencies as oral dosage forms for peptide drugs by focusing on their effects on the gastrointestinal (GI) transit of drugs. The surface of the liposomes was coated with poly(ethylene glycol) 2000 (PEG-Lip) or the sugar chain of mucin (Mucin-Lip). As a model peptide drug, insulin was encapsulated in these liposomes. Coating the surface with poly(ethylene glycol) was found to reduce the transit rate of liposomes in the small intestine after oral administration to rats in vivo. Mucin-Lip was retained in the stomach longer than PEG-Lip or uncoated liposomes. The effect of surface coating on the intestinal transit of liposomes was determined by means of in situ single pass perfusion in the rat small intestine. Statistical moment analysis was applied to the outflow pattern of both liposomes and encapsulated insulin. The mean transit time (MTT) and deviation of transit time (DTT) in the intestinal tract were calculated. The MTT of PEG-Lip was much longer than those of uncoated liposomes and Mucin-Lip and was significantly shortened after removal of the intestinal mucous layer. These results indicated that PEG-Lip interacts strongly with the intestinal mucous layer, leading to its slow transit in the intestine. In contrast, coating the liposome's surface with mucin did not affect either the MTT or DTT of liposomes in the intestine. This result is in accordance with the in vivo observation that Mucin-Lip was highly retained in the stomach, but not in any region of the small intestine in vivo. Both the MTT and DTT values of insulin encapsulated in PEG-Lip and Mucin-Lip were almost the same as those of liposomes themselves, suggesting that surface-coated liposomes retained insulin in the intestinal tract. However, MTT and DTT of insulin were significantly shorter than those of uncoated liposomes because these liposomes degraded and released significant amounts of insulin during single pass perfusion. The ability of surface-coated liposomes, especially of PEG-Lip, to interact with the mucus layer and slow the transit rate in the GI tract is considered desirable for oral delivery of peptide drugs. Modification of the liposomal surface with appropriate materials, therefore, should be an effective method by which to achieve the oral delivery of peptide drugs.

Animals↗
PubMed1999

Tracheal barrier and the permeability of hydrophilic drugs and dipeptides.

The permeability of model hydrophilic compounds with different molecular weights and model dipeptides were examined to characterize the tracheal epithelial barrier in in vitro experiments using excised rabbit trachea. 6-Carboxyfluorescein (6-CF; 376 Da) and fluorescein isothiocyanate (FITC)-dextrans (FDs) with varying molecular weights (4 to 70 kDa) were used as model hydrophilic and macromolecular compounds, and glycyl-D-phenylalanine (Gly-D-Phe) and glycyl-L-phenylalanine (Gly-L-Phe) were used as model dipeptides in this experiment. The apparent permeability coefficients (Papp) of 6-CF and FDs with Mw 376 Da to 70 kDa ranged from 2.35x10(-7) to 4.05x10(-10)cm/s and exhibited a good inverse correlation with their molecular weights. The tracheal permeability of 6-CF, FD-4 (4 kDa) and FD-10 (10 kDa) were increased over three fold by 10 mM glycocholate, which is an absorption enhancer. The Papp of Gly-D-Phe was 1.03x10(-6)cm/s and there was no metabolism during tracheal permeation. Gly-L-Phe was immediately degraded in the mucosal fluid and its intact form was not detected in serosal fluid during the 150 min experimental period. These results suggest that absorption of some peptide drugs via the respiratory tract may contribute to their systemic delivery following pulmonary administration by intratracheal insufflation and instillation.

Animals↗
PubMed1999

Evaluation and design of a small portable EMG amplifier with potential RMS output.

The present study attempted to design and evaluate a small portable electromyogram (EMG) amplifier that can output enhanced EMG and its root mean square (RMS) value. The production and design were of a laboratory scale without any special or high cost circuit construction. The designed amplifier was actually innovated according to the actual working conditions based on physiological anthropology. The present amplifier was compared with commercially available products and proved to be of practical use. The device was installed with a sufficiently small body depicting 8-channel variable gain AC amplifier and variable time-window RMS-to-DC converter. The prototype was battery-driven and well-shielded to minimize external noise interference.

Amplifiers, Electronic↗
PubMed1999

Loss of 123I-MIBG uptake by the heart in Parkinson's disease: assessment of cardiac sympathetic denervation and diagnostic value.

UNLABELLED: Myocardial imaging with 123I-metaiodobenzylguanidine (MIBG) was performed on 35 patients with Parkinson's disease and 24 control subjects to evaluate cardiac sympathetic function in patients with Parkinson's disease, verify this phenomenon and examine whether myocardial MIBG uptake and clearance are correlated with the clinical severity of Parkinson's disease. METHODS: We studied 35 patients with Parkinson's disease and 24 control subjects with other central nervous system diseases. The latter group consisted of 12 subjects with other neurodegenerative disorders (4 with spinocerebellar degeneration, 2 with amyotrophic lateral sclerosis, 3 with progressive supranuclear palsy and 3 with corticobasal degeneration and 12 patients with cerebral infarction (CI), 6 with vascular parkinsonism and 6 without it. Early and delayed images of the anterior view were obtained 15 min and 4 h after injection of 123I-MIBG, respectively. MIBG uptake was quantified by calculating a heart-to-mediastinum count (H/M) ratio. RESULTS: The H/M ratio was markedly reduced in the patients with Parkinson's disease (II to V on the Hoehn and Yahr scale) compared with the control subjects. None of the subjects with neurodegenerative diseases showed a marked decrease in myocardial MIBG uptake nor did any subject with CI. CONCLUSION: Our findings indicate that, in Parkinson's disease, a reduction in myocardial MIBG uptake is a very common, specific phenomenon that can be used to detect cardiac autonomic dysfunction to diagnose Parkinson's disease, particularly in patients without typical signs and symptoms.

3-Iodobenzylguanidine↗
PubMed1999

[A case of synchronous bilateral double primary lung cancer successfully treated by Nd-YAG laser therapy and chemotherapy].

A 61-year-old man was admitted to our hospital with the chief complaint of hemosputum. He was a heavy smoker. A chest radiograph revealed a tumor shadow in right S3 which invaded the pulmonary artery. There was also an associated patchy shadow in the periphery as well as ipsilateral pleural effusion. Bronchoscopy revealed a near occlusion with superficial infiltration at the right B3 bronchus and a nodular tumor at the bifurcation between the left upper and lingual division bronchi, which was consistent with endoscopic early lung cancer. Although both tumors were histologically diagnosed as squamous cell carcinoma, this was considered to be a case of synchronous double primary lung cancer due to their mutual isolation. The left tumor was subsequently diagnosed as carcinoma in situ. Following Nd-YAG laser therapy for carcinoma in situ and 4 courses of systemic chemotherapy using TXT and CDDP, bronchoscopy revealed no residual cancerous tissue and no tumor apart from the nodular shadow in right S3 was seen on a radiograph. Subsequent right upper and middle lobectomy and lymph node (R2a) dissection revealed no residual tumors.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

Pick's disease: selective occurrence of apolipoprotein E-immunoreactive Pick bodies in the limbic system.

We carried out immunohistochemical examination of apolipoprotein E (apoE) in brains from two patients with Pick's disease. In these cases 1 and 2, the APOE genotypes were epsilon 3/4 and epsilon 3/3, respectively. In both cases, numerous argyrophilic globular intraneuronal inclusions, Pick bodies (PBs), were distributed widely throughout the brain, and immunohistochemically were occasionally positive for apoE. Interestingly, such apoE-immunoreactive PBs were virtually restricted to neurons in the limbic system; in the dentate gyrus, the proportion of apoE-immunoreactive PBs relative to the total number of argyrophilic PBs was 5.0% in case 1 and 2.7% in case 2, whereas in the frontal and temporal neocortices it was less than 0.1% in both cases. Diffuse cytoplasmic immunoreactivity for apoE was found in only a few limbic system neurons without PBs in both cases. In conclusion, it is considered that apoE may not be positively involved in the process of PB formation and that the preferential distribution of apoE-immunoreactive PBs in the limbic system may reflect the presence of certain regional factors associated with the synthesis or metabolism of apoE in this particular system.

Aged↗
PubMed1998

Influence of absorption enhancers (bile salts) and the preservative (benzalkonium chloride) on mucociliary function and permeation barrier function in rabbit tracheas.

Effects of bile salts and benzalkonium chloride on the ciliary beat activity (frequency) and the mucociliary transport rate of tracheas, and permeabilities of 6-carboxyfluorescein (6-CF; Mw 376) and FITC-dextrans (FD-4; Mw 4300) as hydrophilic compounds through trachea were investigated for intratracheal delivery of drugs. Ciliary beat activity was measured by an in vitro photoelectric method by using excised rabbit tracheas. Transport rate was determined by an in vivo endoscopic method in rabbit tracheas. Permeation test was carried out by using excised rabbit tracheas. The ciliary beat activities and mucociliary transport rates were not significantly affected by 1, 10 and 20 mM sodium glycocholate, while they were significantly decreased by 1 and 10 mM sodium taurodeoxycholate and immediately halted after application of 20 mM taurodeoxycholate. They were not significantly affected by 0.02% of benzalkonium chloride, whereas they were completely halted by 0.05% of benzalkonium chloride. The apparent permeability coefficients (Papp) of 6-CF and FD-4 were 2.35x10(-7) and 2.22x10(-8) cm/s, respectively. One mmol of glycocholate did not significantly increase the Papp of 6-CF and FD-4, while, 10 mM of glycocholate and 1 and 10 mM of taurodeoxycholate significantly increased the Papp. Benzalkonium chloride (0.01%) did not significantly increase the Papp of 6-CF, whereas 0.03% significantly increased the Papp of 6-CF. Benzalkonium chloride (0.01 and 0.03%) slightly increased the Papp of FD-4. Therefore, sodium glycocholate may be a safe and useful absorption enhancer for intratracheal delivery of drugs.

Animals↗
PubMed1998

Efficiency of targeted gene delivery of ligand-poly-L-lysine hybrids with different crosslinks.

Hybrids of a ligand protein crosslinked to a DNA binding protein have been developed as gene delivery vehicles mediated by receptors. To identify the effect of the crosslinks between the ligand and DNA binding protein on gene expression caused by an internalized hybrid-DNA complex, we prepared two kinds of transferrin-poly-L-lysine (TF-PL) hybrids: one was crosslinked by probably cleavable disulfide bonds (TF-ss-PL) and the other was linked by a probably uncleavable Schiff's base (TF-Schiff-PL). The binding affinity of the hybrids to HeLa cells was not different. However, the expression of a reporter gene (for luciferase) bound to these hybrids in HeLa cells transfected with TF-Schiff-PL was greater than that of TF-ss-PL.

Asialoglycoproteins↗
PubMed1998

Estimation of thermal sensation during varied air temperature conditions.

Seven male students were exposed to four varied air temperature environments: hot (37 degrees C) to neutral (27 degrees C) (HN), neutral to hot (NH), cool (17 degrees C) to neutral (CN), and neutral to cool (NC). The air temperature was maintained at the first condition for 20 min, then was changed to the second condition after 15 min and was held there for 20 min. Each subject wore a T-shirt, briefs, trunks, and socks. Each sat on a chair and was continuously evaluated for thermal sensation, thermal comfort, and air velocity sensation. Some physiological and thermal parameters were also measured every 5 s during the experiment. The correlation between thermal sensation and skin temperature at 15 sites was found to be poor. The subjects felt much warmer during the rising phase of the air temperature (CN, NH) than during the descending phase (HN, NC) at a given mean skin temperature. However, thermal sensation at the same heat flux or at the same value of the difference between skin and air temperature (delta(Tsk - Ta)) was not so different among the four experimental conditions, and the correlation between thermal sensation and heat flux or delta(Tsk - Ta) was fairly good. The multiple regression equation of the thermal sensation (TS) on 15 sites of skin temperature (Tsk; degrees C) was calculated and the coefficient of determination (R*2) was found to be 0.656. Higher coefficients of determination were found in the equations of thermal sensation for the heat flux (H; kcal.m-2.h-1) at the right and left thighs of the subjects and on delta(Tsk - Ta) (degrees C) at 4 sites. They were as follows: TS = 2.04 - 0.016 Hright - 0.036 Hleft; R*2 = 0.717, TS = 1.649 + 0.013 delta(Tsk - Ta)UpperArm - 0.036 delta(Tsk - Ta)Chest - 0.223 delta(Tsk - Ta)Thigh-0.083 delta(Tsk - Ta)LowerLeg; R*2 = 0.752, respectively.

Adult↗
PubMed1997

Neuropathology of sporadic amyotrophic lateral sclerosis of long duration.

We performed post-mortem examinations of three patients with progressive neurogenic amyotrophy of long duration. One patient had been clinically diagnosed as having sporadic amyotrophic lateral sclerosis (ALS) and two had been diagnosed with progressive spinal muscular atrophy (PSMA). The disease durations were 10, 17 and 20 years, respectively, and all of the patients died of respiratory failure with no artificial respiratory support. In all of the patients, both the upper and lower motor neuron systems were affected; degeneration of the former was definite, but was milder than that usually encountered in sporadic ALS patients, and the histopathology of the latter was identical to that of sporadic ALS. Light microscopy revealed Bunina bodies, which are characteristic of sporadic ALS, in the remaining anterior horn cells of each patient. In addition, ubiquitin-positive skein-like inclusions were also identified, immunohistochemically, in the remaining anterior horn cells of each patient. Neuron counts indicated that the number of neurons was preserved in Clarke's column in these patients, but was significantly reduced in the intermediolateral nucleus, compared with control subjects. Based on these findings, we think that these three patients, with long disease durations, were affected by essentially the same underlying disease process as that of sporadic, classical ALS. Moreover, we question the neuropathological occurrence of sporadic ALS without involvement of the upper motor neuron system, namely, pure PSMA or lower motor neuron disease.

Aged↗
PubMed1996

Development of fat within a meningioma.

We report a tentorial meningioma containing fat. Multiple areas of fatty density or intensity in the tumour were seen on CT and MRI, which corresponded histologically to lipomatous components. CT 10 years previously had demonstrated a smaller tumour without evidence of fatty components. We found only five cases in the literature in which fatty density was demonstrated within a meningioma on CT and a lipomatous component histologically proved. Xanthomatous change, with lipid in tumour cells, causes decrease in density on CT, but not to the levels of fat. As both lipomatous components and xanthomatous change show similar intensity on MRI, CT can be helpful in differentiating these two conditions. To our knowledge, our case is the only one in which the advent of fatty tissue was confirmed during follow-up.

Adipose Tissue↗
PubMed1996

Corticobasal degeneration with neither argyrophilic inclusions nor tau abnormalities: a new subgroup?

In corticobasal degeneration (CBD), cerebral cortical neuronal loss with achromasia and degeneration of the subcortical nuclei, particularly the substantia nigra, are common. Recent studies have suggested that the occurrence of argyrophilic nigral inclusions, resembling the neurofibrillary tangles found in progressive supranuclear palsy, and widespread tau abnormalities may be features of CBD. We studied brain tissues from two patients in whom CBD was suspected clinically. From the distribution of their cortical and subcortical lesions, the patients were diagnosed as having CBD. However, Gallyas/tau-positive neuronal and glial structures were not found, which suggests there may be a subgroup of CBD with neither argyrophilic inclusions nor tau abnormalities.

Aged↗