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Biomedical subjects

T Fukunaga

Publications and source records attributed to T Fukunaga.

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

Primary sequence of the envelope glycoprotein of a dengue type 2 virus isolated from patient with dengue hemorrhagic fever and encephalopathy.

Dengue viruses exist in nature as a collection of highly similar but not identical members (quasispecies). In order to correlate the presence of viral quasispecies with rare occurrence of unusual clinical manifestations in dengue-infected individuals, a dengue type 2 virus was isolated from the peripheral blood of a 12-year-old boy who presented with fever, headache, drowsiness and tonic seizure of the left arm, and subsequently manifested symptoms and signs of dengue hemorrhagic fever. Analysis of the envelope glycoprotein sequence of the encephalopathy-associated virus and two other dengue type 2 viruses from the same epidemic season in Chiang Mai, Thailand revealed that all three viruses belonged to the subtype IIIa of the five-subtype phylogenetic nomenclature system for dengue type 2 virus. The encephalopathy-associated dengue virus was more divergent from the others and was characterized by an Ala-->Val substitution at the position 173 of the envelope glycoprotein. This substitution mapped to the central domain 1 which was not known to be involved directly in envelope-receptor interaction.

Amino Acid Sequence↗
PubMed1995

Ultrasonography gives directly but noninvasively elastic characteristic of human tendon in vivo.

To obtain an insight into tendon elasticity during human movement, a real-time ultrasonography was applied to the contracting tibialis anterior muscle. The insertion point of fascicles onto the aponeurosis was clearly visualized, and its position relative to a fixed marker on the skin moved proximally (delta 1) according to the increasing dorsiflexion force (delta F) with a fixed ankle joint. Notably, the delta 1-delta F relationship in the tendon was found to be quadratic in nature (delta F = c delta 1(2); c = 1.48-2.24, r = 0.985-0.992, n = 9) as has been reported in the isolated tendon, although the delta F-delta 1 curves were slightly underestimated in comparison with the stiffness constant estimated from tendon architecture. This underestimation might be caused by changes in the height of the foot arch with the application of force.

Adult↗
PubMed1995

Increased plasma levels of soluble thrombomodulin in patients with sepsis and organ failure.

The fact that thrombomodulin (TM) is released into the bloodstream from damaged vascular endothelial cells led us to hypothesize that plasma levels of soluble TM could be an indicator of the development of organ failure. In this study, we examined the changes in plasma levels of TM in 60 septic patients and 13 postsurgical patients, and investigated the circulating levels of interleukin 6 (IL-6) and polymorphonuclear leukocyte elastase (PMN-E) to determine the mechanism causing the excess liberation of TM. The arterial ketone body ratio (AKBR) was also measured as an indicator of the hepatocyte energy state. Of the 60 septic patients, 26 developed organ failure, 10 of whom died. In contrast, none of the postsurgical patients developed organ failure. The mean plasma level of TM was significantly higher in the septic patients who developed organ failure compared to those without organ failure (P < 0.001) or the postsurgical patients (P < 0.001). Furthermore, those patients whose plasma TM values became elevated over 6.0 ng/ml frequently developed complications. A positive correlation was also observed between the plasma TM levels and the IL-6 (P < 0.01) and PMN-E levels (P < 0.01). In contrast, a negative correlation was seen between the plasma TM levels and the AKBR (P < 0.01). These findings show that plasma TM could be a useful indicator of impending organ failure during sepsis.

Adult↗
PubMed1995

Measurement of muscle fibre displacement during contraction by real-time ultrasonography in humans.

The contact point (P) made by both the echoes of the aponeurosis and from interspaces among fascicles of the tibialis anterior muscle was detected by real-time ultrasound scanning in 12 adults. Movement in the location of P was observed during muscle contraction and its displacement was related to changes in ankle joint angles (r = 0.81, P < 0.01), i.e., P shifted proximally when the ankle joint was dorsiflexed. There was also a significant positive correlation between the degree of dorsiflexion and the velocity related to the change in location of P (r = 0.84, P < 0.01). Ultrasound measurements of the displacement and the velocity of P were reproducible as there was no variation noticed among measurements on different days. It is suggested from these results that the displacement of P reflected changes in muscle length during contraction and that this amount of change corresponded to changes in joint angles.

Adult↗
PubMed1995

Training-induced changes in muscle architecture and specific tension.

Five men underwent unilateral resistance training of elbow extensor (triceps brachii) muscles for 16 weeks. Before and after training, muscle layer thickness and fascicle angles of the long head of the triceps muscle were measured in vivo using B-mode ultrasound, and fascicle lengths were estimated. Series anatomical cross-sectional areas (ACSA) of the triceps brachii muscle were measured by magnetic resonance imaging, from which muscle volume (Vm) was determined and physiological cross-sectional area (PCSA) was calculated. Elbow extension strength (isometric; concentric and eccentric at 30, 90 and 180 degrees.s-1) was measured using an isokinetic dynamometer to determine specific tension. Muscle volumes, ACSA, PCSA, muscle layer thickness and fascicle angles increased after training and their relative changes were similar, while muscle and fascicle length did not change. Muscle strength increased at all velocities; however, specific tension decreased after training. Increase in fascicle angles, which would be the result of increased Vm and PCSA, would seem to imply the occurrence of changes in muscle architecture. This might have given a negative effect on the force-generating properties of the muscles.

Adult↗
PubMed1995

A cross-sectional study of the size and strength of the lower leg muscles during growth.

The influences of age and sex on the cross-sectional area (CSA) and isometric strength of the ankle dorsiflexors and plantarflexors (PF) were investigated in four age groups of 121 boys and 121 girls aged: 7-9, 10-12, 13-15, and 16-18 years. A single anatomical cross-section was determined at 30% of the distance from the articular cleft between the femur and tibiacondyles by using an ultrasonic apparatus. In both sexes, the increase in age was associated with significant increases in the CSA and strength (ST) of these opposing muscle groups. The sex differences became apparent in the 13-15 year group for CSA and in the 16-18 year group for ST but the differences reduced considerably when CSA and ST were expressed per unit of the second power of the lower leg length (CSA.LL-2) and the product of CSA and the lower leg length (ST.CSA-1.LL-1), respectively. However, CSA.LL-2 of both muscles had a tendency to be increased at and over the age of 10-12 years, and was the highest at 16-18 years, and ST.CSA-1.LL-1 of PF showed higher values in the older boys than in the younger. Thus, it appeared that, at least in the reciprocal muscle groups of the ankle joint, the sex differences in muscle CSA and ST during growth could be accounted for by differences in LL and muscle mass, respectively. However, other factors must also be involved to explain completely the age differences in these variables.

Adolescent↗
PubMed1995

Fatigability during repetitive maximal knee extensions in 14-year-old boys.

The isokinetic forces, during 50 repeated maximal knee extensions with a constant velocity of 3.14 rad.s-1, and muscle cross-sectional area (CSA) of the quadriceps femoris muscles were measured for boys aged 14 years (n = 26) and young adult men (n = 26). As representative scores in the maximal session, the mean values of force (F) of every five consecutive and all trials were calculated. The CSA was measured by using a B-mode ultrasound technique at the midpoint of the thigh length (lt). The average values of F at the 1st-5th contractions were 193 (SEM 12) N for the boys and 303 (SEM 13) N for the young adults. The average decline of F with 50 contractions, expressed as a percentage of the value in the 1st-5th trial, was higher in the young adults than in the boys: F for the young adults was reduced by 48 (SEM 2.9)%, for the boys by 36 (SEM 3.1)%. The F of every five consecutive and all trials were significantly correlated to the product of CSA and lt (CSA.lt) in separate groups: for the boys r = 0.762-0.894 (P < 0.01), for the young adults r = 0.598-0.837 (P < 0.01). In a trial range between the 1st-5th and 11th-15th contractions, the young adults showed significantly higher values in the ratio of F to CSA.lt (F.CSA-1.lt-1) than the boys. However, the difference between groups of the ratio on and after the 16th-20th trial and for all trials became insignificant. Thus, at least for 50 maximal repeated knee extensions, the 14-year-old boys were inferior to the young adults in their ability to produce force during the earlier sessions even when the difference in muscle size was allowed for. The inferiority in the boys might be attributed to a lower reliance on glycolysis as pointed out in previous biochemical studies.

Adolescent↗
PubMed1995

Moment of inertia of whole body using an oscillating table in adolescent boys.

This study measured the moment of inertia of the body using the oscillating table method, and saw how it is affected by age and body size. One hundred and seventeen subjects of junior and senior high school boys of ages 13-18 participated in this study. Moment of inertia was measured in two postures of supine (Imx) and recumbent (Imy) positions. Both Imx and Imy account for the range from 5.6 to 14.0 kg m2 and 4.2 to 13.5 kg m2, respectively, and correlate linearly to body height (Ht) and body weight (W). The values of Imy/Imx becomes 93.6 and 95.2% independent of age and body size. The difference between Imx and Imy might be affected by projection areas on the frontal from the sagittal area of the body. The multiple regression analysis of Ht2 and W with regard to Im was performed to obtain the following multiple regression equations: Imx = 3.44 Ht2 + 0.144 W - 8.04 (R = 0.973), Imy = 3.52 Ht2 + 0.125 W - 7.78 (R = 0.972). When Imx and Imy were estimated using these equations, the standard deviation of error which calculates the percent differences between the estimated and measured values amounted to +/- 5% in Imx and Imy. The results suggest that, with Japanese boys, there is a relationship between the postures and body size (height or weight), independent of age.

Adolescent↗
PubMed1995

Strength and cross-sectional areas of reciprocal muscle groups in the upper arm and thigh during adolescence.

The purpose of this study was to investigate the development in muscle cross-sectional area (CSA) and strength capability of the reciprocal muscle groups in the upper arm and thigh. Subjects were 130 boys aged 7 to 18 years; 7-9 yr aged-group (n = 30), 10-12 yr (n = 30), 13-15 yr (n = 35), and 16-18 yr (n = 35). Anatomical CSAs of elbow flexors (EF), elbow extensors (EE), knee flexors (KF) and knee extensors (KE) were determined with a B-mode ultrasound apparatus. Isokinetic strength during elbow or knee extension as well as elbow or knee flexion was measured by using a Cybex II isokinetic dynamometer at the pre-set constant velocity of 60 degrees/s. The effect of age associated with a significant increase in both CSA and strength with a marked increase in 13-15 yr. The elder aged-groups had a significantly higher ratio of strength to muscle CSA than in the lower aged-groups. The effect of age on EF/EE CSA ratio was not significant, but EF/EE strength ratio was the highest in 16-18 yr and the lowest in 7-9 yr. With advancing age, KF/KE CSA ratio had a tendency to increase, but KF/KE strength ratio remained almost unchanged. These results indicate that (1) children in the pre-puberty or the early stage of puberty do not develop strength in proportion to their muscle CSA, and (2) the flexors and extensors in limbs have reciprocally different growth rates in either CSA or strength even in the same region.

Adolescent↗
PubMed1995

A quantative in vivo method of analyzing human tumor-induced angiogenesis in mice using agarose microencapsulation and hemoglobin enzyme-linked immunosorbent assay.

This study was conducted to develop a quantitative assay system for use in the in vivo evaluation in mice of angiogenesis induced by human tumor cells. The human epidermoid carcinoma cells, A431 cells, were cultured on microcarriers. Microcarrier-attached A431 cells (A431-MC) were microencapsulated with agarose hydrogel to isolate them from the immune system of the C57BL/6 mice after subcutaneous dorsal midline implantation. The agarose hydrogel-microencapsulated A431 cells (Aga-A431 cells; diameter=300 micron) survived for at least 10 days in vitro, and the proliferation profile of the Aga-A431 cells was indistinguishable from that of non-microencapsulated A431 cells. The Aga-A431 cells were subcutaneously injected into mice with an 18-gauge needle. Ten days later, few vessels had formed at the site implanted with cell-free agarose beads, whereas notable angiogenesis was observed at the site implanted with Aga-A431 cells. The degree of angiogenesis was evaluated by measurement of the hemoglobin content in the implanted site using a mouse hemoglobin (mHb) enzyme-linked immunosorbent assay (ELISA) system. This mHb-ELISA system has the advantages of great simplicity and reproducibility. The measured mHb-content of new blood vessels at the site implanted with agarose beads was in good agreement with the amount of angiogenesis observed under a stereoscopic microscope. This assay system enabled us to evaluate the angiogenesis induced by xenogeneic cells, such as human tumor cells. Thus, our novel method may be useful for the study of the angiogenic potential of various human tumor cells and in research on the anti-angiogenic properties of various agents.

Animals↗
PubMed1995

Effects of steroidal glycosides on blood glucose in normal and diabetic mice.

Two steroidal glycosides, PO-1 and PO-2, were tested as a new hypoglycemic drug. PO-2 showed remarkable hypoglycemic activity on i.p. injection into normal mice. PO-1 slightly lowered the blood glucose in normal mice. Furthermore, PO-1 and PO-2 exhibited significant hypoglycemic effects in streptozotocin-induced diabetic mice. However, a steroid, diosgenin, did not affect the blood glucose level in either normal or streptozocin-induced diabetic mice, indicating that the branching glucose units are essential for the biological activity.

Animals↗
PubMed1995

Use of B-mode ultrasound for visceral fat mass evaluation: comparisons with magnetic resonance imaging.

The validity of the visceral fat evaluation based on B-mode ultrasonography was tested on 30 healthy young women (mean age 19.6 years). The mass of visceral fat (VFM) was estimated by subtracting the subcutaneous fat mass (SFM) from the total body fat mass. The SFM was calculated as the sum of segmental subcutaneous fat mass determined from the surface area and mean thickness of adipose tissue in six body segments (face and neck, upper arm, forearm, thigh, lower leg, and trunk). Reproducibility of the determination of VFM by the repeated measures of SFM and total fat mass was sufficiently high with the difference of 5.0%. Serial cross-sectional areas of visceral adipose tissue (VATarea) were measured by magnetic resonance imaging (MRI) at three different positions of the trunk (at umbilicus and at 3.5 cm upper and lower positions). The VFM correlated significantly to each VATarea (r = 0.75 to r = 0.78, P < 0.01). The present findings suggest that the VFM can be determined with the use of B-mode ultrasonography for the clinical assessment and field surveys.

Adipose Tissue↗
PubMed1995

Osteogenesis in xenogeneic bone transplantation, using an immunosuppressant. Rabbit-rat experiments.

We investigated osteogenesis and lymphocyte subsets in xenogeneic bone transplantation, using the immunosuppressant FK506 (FK). Iliac bones of rabbits were transplanted as fresh and frozen xenogeneic bone grafts into an intramuscular pouch of rats. FK was injected intramuscularly in half of the rats in a dose of 3 mg/kg/day for 14 days after transplantation. At 2, 4, and 8 weeks, transplanted grafts and the lymphocyte subsets of these rats were examined. In the group not given FK, the grafted bone became necrotic and infiltrated with small round cells around the trabeculae. In the FK group, at 2 and 4 weeks, new bone was formed in the fresh xenografts without infiltration of lymphocytes. At 8 weeks, the new bone became necrotic and lymphocytes were present. The percentage of T cells (CD 5), B cells and the ratio of CD 4 cells/CD 8 cells were smaller in the FK group. Using an immunosuppressant we concluded that xenogeneic bone has an osteogeneic potency.

Animals↗
PubMed1995

[Effect of endogenous and inhaled nitric oxide on pulmonary microcirculation].

The sites of action of endogenous and inhaled nitric oxide (NO) were reassured during hypoxic pulmonary vasoconstriction. Lungs of 21 adult cats were perfused in situ with autologous blood in zone-3 conditions. Capillary pressures were measured by the double-occlusion techniques and pressures in arterioles and venules 70-100 microns in diameter were measured by the servo-null micropuncture technique, both during normoxia (FiO2 = 0.3) and during hypoxia (FiO2 = 0.02). The effects of NG-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg), an inhibitor of NO synthase, and of inhaled NO (5-100 ppm) were also measured. The PO2 of the prefusate decreased from 187.6 +/- 5.3 mmHg during normoxia to 25.7 +/- 1.3 mmHg during hypoxia, and further decreased to 20.8 +/- 2.2 mmHg during hypoxia with 50 ppm NO (p < 0.05, compared with hypoxia only). Increases in pulmonary vascular pressure drop in response to hypoxia were 4.8 +/- 1.0 cmH2O and 9.1 +/- 1.4 cmH2O in non-treated and L-NAME-treated lungs, respectively (p < 0.05). L-NAME significantly increased hypoxic construction in the venous segment. The concentration of exhaled NO increased from 13 +/- 4 ppb during normoxia to 18 +/- 4 ppb during hypoxia (p < 0.1). Inhaled NO lowered not only pulmonary artery pressure but also capillary pressure in a dose-dependent manner, which reduced hypoxic pulmonary vasoconstriction. Pulmonary veins were more sensitive to inhaled NO than were arteries. Inhaled NO (50 ppm) dilated vessels smaller than 70 to 100 microns in diameter, by 39% (p < 0.05), and dilated venules greater than 100 microns in diameter by 26% (p < 0.05), but did not significantly dilate arterioles greater than 100 microns in diameter (11%). Inhaled NO did not significantly change the ratio of wet weight to dry weight. We conclude that both endogenous and inhaled NO attenuate hypoxic pulmonary vasoconstriction, with significant pulmonary venous dilation. The main site of action of inhaled NO is vessels smaller than 100 microns in diameter and venules greater than 100 microns in diameter. Inhaled NO (5-100 ppm) does not cause interstitial edema.

Administration, Inhalation↗
PubMed1994

Inhibition of tubular morphogenesis in human microvascular endothelial cells by co-culture with chondrocytes and involvement of transforming growth factor beta: a model for avascularity in human cartilage.

Tube formation in collagen gel was induced in human omental microvascular endothelial (HOME) cells in the presence of epidermal growth factor (EGF) or transforming growth factor-alpha (TGF-alpha). TGF-alpha enhanced the expression of the tissue type plasminogen activator (t-PA) gene, whereas TGF-beta increased the expression of the PA inhibitor-1 (PAI-1) gene and inhibited that of the t-PA gene. TGF-beta inhibited the tube formation of HOME cells in type I collagen gel that was enhanced in response to TGF-alpha. We have recently established an angiogenesis model in vitro in which vascular endothelial cells on type I collagen gel in an inner chamber are co-cultured with other types of cells in an outer chamber. Here we examined whether the EGF/TGF-alpha-induced tube formation in HOME cells was modulated by human chondrocytes co-culture in the outer chamber. TGF-alpha-dependent tube formation of HOME cells was inhibited when human chondrocytes were co-cultured in the outer chamber. This chondrocyte-induced inhibition of tube formation was partly abrogated by co-administration of anti-TGF-beta antibody. These findings suggest that TGF-beta is partly involved in the human chondrocyte-dependent inhibition of tube formation by human microvascular endothelial cells. This is the first model system demonstrating that avascularity of human chondrocytes is partly due to TGF-beta family produced from them.

Cartilage↗
PubMed1994

Phylogenetic subtypes of human T-lymphotropic virus type I and their relations to the anthropological background.

Isolates of human T-lymphotropic virus type I (HTLV-I) were phylogenetically analyzed from native inhabitants in India and South America (Colombia and Chile) and from Ainu (regarded as pure Japanese descendants from the preagricultural "Jomon" period). Their genomes were partially sequenced together with isolates from Gabon in central Africa and from Ghana in West Africa. The phylogenetic tree was constructed from the sequence data obtained and those of previously reported HTLV-I isolates and simian T-lymphotropic virus type I (STLV-I) isolates. The heterogeneity of HTLV-I was recently recognized, and one major type, generally called the "cosmopolitan" type, contained Japanese, Caribbean, and West African isolates. The phylogenetic tree constructed in the present study has shown that this cosmopolitan type can be further grouped into three lineages (subtypes A, B, and C). Subtype A consists of some Caribbean, two South American, and some Japanese isolates, including that from the Ainu, in addition to an Indian isolate, and subtype B consists of other Japanese isolates in addition to another Indian isolate, suggesting that there might be at least two ancestral lineages of the Japanese HTLV-I. Subtype A implies a close connection of the Caribbean and South American natives with the Japanese and thereby a possible migration of the lineage to the American continent via Beringia in the Paleolithic era. Subtype C consists of the West African and other Caribbean isolates, indicating that not all but part of the Caribbean strains directly originated from West Africa probably during the period of slave trade. The tree also has shown that the HTLV-I isolate from Gabon in central Africa forms a cluster with STLV-I from a chimpanzee, suggesting a possible interspecies transmission between man and the chimpanzee in the past. No specific clustering was observed in the tree in relation to manifestations of the disease such as adult T-cell leukemia and HTLV-I-related neurological disorders. Thus, the topology of the phylogenetic tree reflects the movement of people carrying the virus in the past.

Adult↗