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Biomedical subjects

K Kubo

Publications and source records attributed to K Kubo.

At least 55 records · Page 3Linked to original sources
PubMed2001

In vivo behaviour of human muscle tendon during walking.

In the present study we investigated in vivo length changes in the fascicles and tendon of the human gastrocnemius medialis (GM) muscle during walking. The experimental protocol involved real-time ultrasound scanning of the GM muscle, recording of the electrical activity of the muscle, measurement of knee- and ankle-joint rotations, and measurement of ground reaction forces in six men during walking at 3 km h(-1) on a treadmill. Fascicular lengths were measured from the sonographs recorded. Musculotendon complex length changes were estimated from anatomical and joint kinematic data. Tendon length changes were obtained combining the musculotendon complex and fascicular length-change data. The fascicles followed a different length-change pattern from those of the musculotendon complex and tendon throughout the step cycle. Two important features emerged: (i) the muscle contracted near-isometrically in the stance phase, with the fascicles operating at ca. 50 mm; and (ii) the tendon stretched by ca. 7 mm during single support, and recoiled in push-off. The behaviour of the muscle in our experiment indicates consumption of minimal metabolic energy for eliciting the contractile forces required to support and displace the body. On the other hand, the spring-like behaviour of the tendon indicates storage and release of elastic-strain energy. Either of the two mechanisms would favour locomotor economy

Adult↗
PubMed2001

Results of three-year mass screening programme for lung cancer using mobile low-dose spiral computed tomography scanner.

The aim of this study was to evaluate the usefulness of annual screening for lung cancer by low-dose computed tomography (CT) and the characteristics of identified lung cancers. Subjects consisted of 5483 general population aged 40-74 years, who received initial CT scans in 1996, followed by repeat annual scans for most subjects in 1997 and 1998, with a total of 13 786 scans taken during 1996-1998. Work-up examinations for patients with suspicious lesions were conducted using diagnostic CTs. The initial screening in 1996 detected suspicious nodules in 279 (5.1%) of 5483 subjects, and 22 (8%) were confirmed surgically to have lung cancer. Corresponding figures in 1997 and 1998 screening studies were 173 (3.9%) of 4425 and 25 (14%) of 173, and 136 (3.5%) of 3878 and 9 (7%) of 136, respectively. The sensitivity and specificity of detecting surgically confirmed lung cancer were 55% (22/40) and 95% (4960/5199) in 1996 and 83% (25/30) and 97% (4113/4252) in 1997 screening, respectively. 88% (55/60) of lung cancers identified on screening and surgically confirmed were AJCC stage IA. Our trial allowed detection of nearly 11 times the expected annual number of early lung cancers. Repeat CT allowed the detection of more aggressive, rapidly growing lung cancers, compared to those in the initial screening.

Adult↗
PubMed2001

Assessment of the capillary zone electrophoretic behavior of proteins in the presence of electroosmotic modifiers: protein-polyamine interaction studied using a polyacrylamide-coated capillary.

The use of polyamines as electroosmotic modifiers has been shown to be effective in enhancing resolution of protein glycoforms in capillary zone electrophoresis (CZE) using a bare capillary tube. In this study, effectiveness was evaluated by using a polyacrylamide-coated capillary tube instead of a bare capillary tube. Electropherograms obtained in the presence of polyamines were inferior to those obtained in their absence with respect to resolution. Electrophoretic mobility of the proteins decreased and their peaks were broadened by polyamines bound to them. This unfavorable effect was dependent on both the species of polyamines and the pH values of the electrolyte buffer. The reduction of resolution caused by polyamines was in the following order: spermidine (SPD) approximately spermidine-tri-hydrochloride (SPD-HCI) > putrescine (PUT) > hexamethonium chloride (HMC). The observed effect can be ascribed to the formation of complexes between the proteins and the polyamines. In addition, for the bare capillary tube the complexes showed interaction with the inner surface, resulting in local suppression of electroosmosis and poor resolution. The high resolution obtained in the coated capillary tube was reduced in the presence of the polyamines. Thus, the use of the polyamines has a negative effect on the analysis of protein microheterogeneity as a result of protein-polyamine interaction.

Acrylic Resins↗
PubMed2001

Is passive stiffness in human muscles related to the elasticity of tendon structures?

The purpose of this study was to examine in vivo whether passive stiffness in human muscles was related to the elasticity of tendon structures and to performance during stretch-shortening cycle exercise. Passive torque of plantar flexor muscles was measured during passive stretch from 90 degrees (anatomical position) to 65 degrees of dorsiflexion at a constant velocity of 5 degrees.s-1. The slope of the linear portion of the passive torque-angle curve during stretching was defined as the passive stiffness of the muscle. The elongation of the tendon and aponeurosis of the medial gastrocnemius muscle (MG) was directly measured using ultrasonography during ramp isometric plantar flexion up to the voluntary maximum. The relationship between the estimated muscle force of MG and tendon elongation was fitted to a linear regression, the slope of which was defined as the stiffness of the tendon. In addition, the dynamic torques during maximal voluntary concentric plantar flexion with and without prior eccentric contraction were determined at a constant velocity of 120 degrees.s-1. There were no significant correlations between passive stiffness and either the tendon stiffness (r = 0.19, P > 0.05) or the relative increase in torque with prior eccentric contraction (r = -0.19, P > 0.05). However, tendon stiffness was negatively correlated to the relative increase in torque output (r = -0.42, P < 0.05). The present results suggested that passive stiffness was independent of the elasticity of tendon structures, and had no favourable effect on the muscle performance during stretch-shortening cycle exercise.

Adult↗
PubMed2001

Phase I trial of weekly docetaxel combined with cisplatin in patients with non-small cell lung cancer.

The phase I study was conducted to evaluate the maximum tolerated dose (MTD) and toxicity of weekly administered docetaxel combined with cisplatin in patients with non-small-cell lung cancer (NSCLC). In a dose escalation study, 22 patients, under 75 years old, with unresectable and metastatic untreated NSCLC with performance status (0-1) were enrolled. Patients were treated with cisplatin (day 1) and weekly docetaxel (days 1, 8, 15). Dose escalation levels in mg/m(2) were for cisplatin and docetaxel; 70 and 15 (level 1), 80 and 15 (level 2), 80 and 20 (level 3), 80 and 25 (level 4), 80 and 30 (level 5), respectively. Chemotherapy was repeated for at least two cycles every 28 days. All patients were assessable for toxicities. Although grade 3 neutropenia occurred in one case in level 4, there were no significant modifications of chemotherapy schedule until level 4. Grade 3 neutropenia occurred in all cases receiving level 5. One patient developed an infection, and two had incomplete recovery of neutropenia by the 28th day after the first cycle of chemotherapy. Nonhematological toxicities, including nephrotoxicity, nausea/vomiting, alopecia and hypersensitivity reaction, were tolerable. However, one case developed severe hyponatremia. Among 21 patients evaluable for response, eight cases achieved partial response, thus the overall response was 39%. Weekly administration of docetaxel at 25 mg/m(2) (days 1, 8, 15) combined with cisplatin 80 mg/m(2) (day 1) is recommended for phase II studies. The responses observed in the present study suggest an identical high degree of activity against NSCLC with less hematotoxicity compared with a standard schedule of cisplatin and docetaxel.

Adult↗
PubMed2001

Inactivity and muscle: effect of resistance training during bed rest on muscle size in the lower limb.

The present study aimed to investigate the effect of dynamic leg press training on the physiological cross-sectional areas (PCSAs) of human lower limb muscles during 20 days of 6 degrees head-down tilt bed rest. Five healthy men comprised the resistance training group (BR-Tr) and data from two previous studies were used to derive a 10-man control group (BR-Cont). The BR-Tr performed two sessions (morning and afternoon session) of dynamic leg press action including knee extension and plantar flexion daily for the bed rest period: (1) three sets of 10 repetitions at 90% of maximum load and (2) 40% of maximum load to exhaustion. The PCSAs of the knee extensor (KE), knee flexor (KF), plantar flexor (PF), and dorsiflexor muscle groups were estimated using serial axial magnetic resonance (MR) images of the right-thigh and leg. After the bed rest period, the BR-Tr showed a significant increase in the PCSA of the KE. Although PCSA of the KF in two groups significantly decreased after bed rest, percentage of change in PCSA of the biceps femoris (long head) and semitendinosus muscles in the BR-Tr, which occupied approximately 70% of the KF, was significantly higher than those in the BR-Cont. Both the BR-Tr and BR-Cont groups showed significant decreases in the PCSA of PF with similar magnitude of 11.6% (P < 0.001) and 11.9% (P < 0.001), respectively. These results suggest that dynamic leg press training during bed rest can prevent deteriorating of the KE and a part of KF, but not the calf muscles.

Adult↗
PubMed2001

Gamma knife radiosurgery for neuroepithelial tumors: radiological and histological changes.

Gamma knife radiosurgery (RS) has been introduced as a modern therapy for brain tumors. However, the effects of RS for neuroepithelial tumors are still obscure. The present study investigates the radiological and histological changes after RS to elucidate the biological effect. There were seven cases (two males and five females), ranging from 4 to 71 years with a mean age of 33 years. Two cases were located in the brainstem, another two in the cerebellum, and one each in the thalamus, the hypothalamus, and the frontal lobe. Histologically, two cases had gangliogliomas, four astrocytomas (1 pilocytic, 1 fibrillary, 2 anaplastic), and one glioblastoma. RS was performed after surgery with a central dose of 30-36 Gy. All cases were evaluated radiologically on MRI before and after RS. Four cases (3 astrocytomas and 1 glioblastoma) which neurologically deteriorated after RS were reoperated. These cases were examined using HE and immunohistochemical studies with antibodies of CD34, alpha-smooth muscle actin (SMA), p53, p21 and MIB-1 on the sections before and after RS. MRI demonstrated perifocal edema and intratumoral hypointensity on T2 weighted imaging (T2WI), suggesting radionecrosis in most of the cases within 6 months after RS. In the central part of the RS, destructive changes were observed in the tumor cells and endothelial cells: decrease in the tumor cell population, coagulation necrosis, and fibrinoid degeneration of vascular walls were revealed. In the peripheral part, however, some tumors contained viable tumor cells intermingled with blood vessels showing endothelial and pericytic proliferations. The increase of MIB-1 staining index was found in only one case. The p21 immunoreactivity was increased in endothelial cells, although the p53 immunoreactivity was unchanged. These results suggested that radionecrosis occurred earlier and more frequently in neuroepithelial tumors after RS than after conventional radiation.

Adolescent↗
PubMed2001

Intravenous digital subtraction angiography and helical computed tomography in evaluation of living renal donors.

OBJECTIVES: The present study was carried out to evaluate the accuracy of helical computed tomography (CT) and intravenous digital subtraction angiography (IV-DSA) on anatomical assessment of renal vasculature for living renal donors. METHODS: Forty-two healthy potential renal donors were prospectively evaluated and 35 subsequently underwent donor nephrectomy after helical CT and IV-DSA evaluation. The vascular and non-vascular findings were compared between the findings on helical CT, IV-DSA and surgery. RESULTS: Ten prehilar branches and five accessory renal arteries were found at nephrectomy. Overall, operative findings agreed with the findings by IV-DSA in 89% and by helical CT in 83%. In delineating accessory arteries, IV-DSA had a sensitivity of 60% and specificity of 97%, whereas helical CT had a sensitivity of 40% and specificity of 100%. In delineating prehilar branches, IV-DSA had a sensitivity of 90% and specificity of 100%, whereas helical CT had a sensitivity of 70% and specificity of 100%. Accessory arteries and prehilar branches that were not detected by helical CT or IV-DSA, were less than 2 mm in diameter and did not require vascular reconstruction. Renal veins were delineated in 63% by IV-DSA, whereas they were clearly imaged by helical CT in all cases, including a case with a circumaortic renal vein. Non-vascular findings were obtained in 64% by helical CT, including two renal tumors. None of these findings were obtained by IV-DSA. CONCLUSION: Helical CT and IV-DSA provide comparably sufficient information on renal artery vasculature. However, helical CT provides significantly more information on venous and non-vascular findings as a single-imaging modality.

Adult↗
PubMed2001

Successful prevention of recurrent ventricular fibrillation by intravenous isoproterenol in a patient with Brugada syndrome.

Intravenous administration of isoproterenol restored the ST-segment configuration to nearly normal in the right precordial leads and completely prevented spontaneous VF attacks in a patient with Brugada syndrome. The formation of a Brugada-type ECG has been attributed to the transmural dispersion of repolarization of the right ventricular epicardium and related to modulation of the autonomic nervous system. Our case may provide clues to the pathophysiological mechanism of this syndrome.

Adult↗
PubMed2001

Two cases of bronchial asthma after treatment with amiodarone.

Amiodarone is a highly effective antiarrhythmic agent for the prevention of life-threatening arrhythmias. Two cases are described of patients who developed bronchial asthma after treatment with amiodarone. The bronchial asthma resolved after the dose of amiodarone was decreased in both patients. To our knowledge, an association between amiodarone and severe bronchial asthma has previously been reported only once in the medical literature. Physicians should note that amiodarone may cause bronchospasm in susceptible patients.

Aged↗
PubMed2001

Influence of various hemodialysis membranes on the plasma (1-->3)-beta-D-glucan level.

BACKGROUND: Recently, invasive fungal infections have increased significantly because of the growing number of immunocompromised hosts. The measurement of plasma (1-->3)-beta-D-glucan has been proposed as a useful diagnostic tool for deep mycosis. In this study, we analyzed the alteration of the plasma (1-->3)-beta-D-glucan concentration by using different kinds of hemodialysis (HD) membranes in end-stage renal disease (ESRD) patients and estimated its half-life. METHODS: Twenty-seven patients with ESRD without known fungal infections (with a median age of 66 years old) were enrolled in this study. Cellulose triacetate (CTA) membrane, cellulose (Cu) membrane, and polymethyl methacrylate (PMMA) membrane were used in three consecutive initiations of HD and plasma (1-->3)-beta-D-glucan concentration was measured before and after each HD session. RESULTS: The level did not change between before and after HD when CTA and PMMA membranes were used. In contrast, the plasma (1-->3)-beta-D-glucan level increased greatly after HD using the Cu membrane (from 9.4 to 332 pg/mL in median). Hypothesizing that the plasma (1-->3)-beta-D-glucan level declines exponentially, its median half-life is estimated at 20 hours, which is not affected by hepatic or renal function. CONCLUSIONS: Because the plasma (1-->3)-beta-D-glucan level increases dramatically after HD using the Cu membrane, dialyzers with Cu membrane should be avoided for HD in patients with suspected deep mycosis. The measurement of plasma (1-->3)-beta-D-glucan is also useful for the patients with hepatic or renal failure.

Adult↗
PubMed2001

Outcomes of hemodiafiltration based on Japanese dialysis patient registry.

Effectiveness of various therapeutic modalities was analyzed among 1,196 patients entered in the registry of the Japanese Society for Dialysis Therapy who were on hemopurification therapy as of the end of 1998 and developed dialysis-related amyloidosis during 1999. In the investigation, the effectiveness of various hemopurification modalities on the dialysis-related amyloidosis was ranked as exacerbation, unchanged, or alleviation, so as to analyze the possible relationship between the hemopurification modality and its effectiveness. The analysis was performed using a logistic regression approach, and the results were shown as "the risk of a worse therapeutic ranking" among the hemopurification modalities. The smaller "the risk of a worse therapeutic effect" was, the more effective the treatment modality. When the risk of a worse therapeutic effect for the hemodialysis patients treated by a regular membrane was put at 1.0, the risk for hemodialysis patients using high-flux membrane was 0.489, the off-line hemodiafiltration risk was 0.117, the on-line hemodiafiltration risk was 0.013, and the risk of push/pull hemodiafiltration was 0.017. For hemodialysis with a beta(2)-microglobulin adsorption column, a low risk of 0.054 was found. The results indicated that hemodiafiltration therapy and simultaneous hemodialysis with beta(2)-microglobulin adsorption therapy were more effective treatment for dialysis-related amyloidosis.

Amyloidosis↗
PubMed2001

Growth changes in the elastic properties of human tendon structures.

The purpose of this study was to investigate the growth changes in the elastic properties of human tendon structures. 9 younger boys (age 10.8 +/- 0.9 years, YBG), 9 elder boys (14.8 +/- 0.3 years, EBG), and 14 young adult men (24.7 +/- 1.6 years, ADG) volunteered to take part in the present study. Using a B-mode ultrasonic apparatus, the elongation of tendon and aponeurosis of vastus lateralis muscle (VL) was noninvasively measured in vivo, while subjects performed the extension of knee joint isometrically with force production levels from zero (relax) to maximal voluntary contraction (MVC) within 5 seconds. A curvilinear relationship was found between elongation of tendon structures (dL) and muscle force (Fm). This relationship consisted of two components, a steep initial change in length followed by a linear-region. The relationship between dL and Fm was fitted to a linear regression, and then the dL and dFm within 50 to 100% MVC was defined as compliance of tendon structures. The MVC force was the greatest in ADG and the lowest in YBG among the three groups. Significant age-related differences were found in compliance; 4.1 +/- 0.9 x 10(-2) mm/N for YBG, 2.9 +/- 1.1 x 10(-2) mm/N for EBG and 1.8 +/- 0.3 x 10(-2) mm/N for ADG. The dL/thigh length (TL) was significantly greater in YBG than in the other two groups above 0.35 MPa of Fm per muscle cross-sectional area (muscle stress). However, there was no significant difference between EBG and ADG in the relationship between dL/TL and muscle stress. The ratio of fascicle length to TL in YBG was significantly lower than those in the other two groups. These results suggest that the tendon structures in younger boys are more compliant than those in older boys and young men. The observed properties of tendon structures in the younger boys may play a role in protecting younger boys from athletic injuries associated with immature muscle-tendon complex.

Adolescent↗
PubMed2001

Histamine stimulates alveolar macrophages to release neutrophil and monocyte chemotactic activity.

Histamine and serotonin are important inflammatory mediators in the pathophysiology of asthma, and asthmatic patients have higher plasma histamine and serotonin levels than non-asthmatic control subjects. Alveolar macrophages (AMs) synthesize and secrete a large number of substances that play a key role in acute and chronic inflammation including asthma. We postulated that AMs might release chemotactic activity for neutrophils and monocytes in response to histamine or serotonin. To test this hypothesis, bovine AMs were cultured, and the supernatant fluids were evaluated for neutrophil chemotactic activity (NCA) and monocyte chemotactic activity (MCA) by a blind well chamber technique. AMs released chemotactic activity in response to histamine and serotonin in a dose- and time-dependent manner (P <.05). Partial characterization and molecular sieve column chromatography revealed that low-molecular-weight lipid-soluble activity was predominant. Lipoxygenase inhibitors significantly blocked the release of chemotactic activity. Leukotriene B(4) receptor antagonists blocked the chemotactic activity. Immunoreactive leukotriene B(4) significantly increased in supernatant fluids in response to histamine and serotonin. The receptor responsible for the release of chemotactic activity in response to histamine was the H2 receptor. These data demonstrate that AMs release NCA and MCA in response to histamine or serotonin (or both) and may modulate the inflammatory cell recruitment into the lung.

Acetates↗
PubMed2001

Pathological features of the lung in fatal high altitude pulmonary edema occurring at moderate altitude in Japan.

In order to characterize the pathological features of high altitude pulmonary edema (HAPE) occurring at moderate altitude in Japan, we performed routine hematoxylin and eosin (HE) staining in lung materials from HAPE autopsied cases. We also undertook advanced immunohistochemical staining for observation of type II pneumocytes, pulmonary surfactant (PS), and mast cells in the lung of HAPE cases to examine the biological changes within the lung parenchyma. The pathological findings of HAPE were characterized by alveolar edema, congestion of pulmonary vessels, alveolar hyaline membranes, alveolar hemorrhage, and multithrombi and fibrin clots, but maintained alveolar structure. The immunostaining results showed that the type II pneumocytes were cellular fusion, deformity, and exfoliation from the walls of alveoli; the PS not only lined the alveolar surface, but was also patchily distributed within alveoli; and the number of mast cells were increased (9.0 +/- 0.9 cells/mm(2)) compared to that in controls (1.1 +/- 0.4 cells/mm(2)) (p < 0.01). We conclude that the pathological features of HAPE at moderate altitude in Japan are similar to others reported worldwide, and that the type II pneumocytes, PS, and mast cells may contribute to some extent to pathophysiological parts in the development and progression of HAPE.

Adolescent↗
PubMed2001

Quantitation of DNA damage by an aldehyde reactive probe (ARP).

DNA is constantly damaged by endogenous and environmental agents. Abasic sites representing a major class of DNA damage can be quantitated by an ELISA-like assay using an aldehyde reactive probe (ARP). It is shown that oxidative pyrimidine lesions can be also quantitated by the ARP assay in combination with the treatment with endonuclease III.

Aldehydes↗
PubMed2001

Two-generation reproductive toxicity study of tributyltin chloride in male rats.

A 2-generation reproductive toxicity study of tributyltin chloride (TBTCl) was conducted in male rats using dietary concentrations of 5, 25, and 125 ppm TBTCl to evaluate its effect on sexual development and the reproductive system. F1 males were killed on postnatal day 119 and F2 males were killed on postnatal day 91. TBTCl affected the male reproductive system of rats. The weights of the testis and epididymis were decreased and homogenization-resistant spermatid and sperm count were reduced mainly in the 125 ppm TBTCl group. Histopathologic changes were also observed in the testis of this group and included vacuolization of the seminiferous epithelium, spermatid retention, and delayed spermiation. However, the changes were minimal in nature. The weight of the ventral prostate was decreased to 84% of the control value in the 125 ppm group in the F1 generation and decreased to 84 and 69% of the control value in the 25 ppm and 125 ppm TBTCl groups, respectively, in the F2 generation. The serum 17beta-estradiol concentration was also decreased to 55% of the control value in the 125 ppm group in the F1 generation and decreased to 78 and 57% of the control value in the 25 ppm and 125 ppm TBTCl groups, respectively, in the F2 generation. However, the serum concentrations of luteinizing hormone (LH) and testosterone were not decreased in these groups. These changes corresponded with those caused by aromatase inhibition and therefore TBTCl might be a weak aromatase inhibitor in male rats.

Animals↗