Biomedical subjects

T Yoshioka

Publications and source records attributed to T Yoshioka.

At least 271 records · Page 15Linked to original sources

PubMed1997

Mild mitral regurgitation reduces exercise capacity in patients with idiopathic dilated cardiomyopathy.

We evaluated 30 patients with dilated cardiomyopathy (New York Heart Association functional Class II or III with medical treatment) to assess the effect of mild mitral regurgitation (MR) on exercise capacity in patients with congestive heart failure. They were classified into two groups based on results of left ventriculography: MR present (n = 10) and MR absent (n = 20). The severity of the MR by left ventriculography was grade I (mild) in all patients with MR. Steady-state hemodynamic data and angiographic data did not differ significantly between the two groups. Heart rate and systolic blood pressure at rest and in response to symptom-limited exercise testing did not differ between the groups. However, the peak work load was significantly lower in the group with MR than that in the group without MR (101 +/- 32 vs. 142 +/- 29 W, respectively; p < 0.005). Peak oxygen uptake and peak oxygen pulse were also significantly lower in the group with MR than in that without MR (peak oxygen uptake: 18 +/- 23 +/- 5 ml/min/kg; p < 0.05, peak oxygen pulse: 6.6 +/- 2.6 vs. 9.5 +/- 2.7 ml/min/beat: p < 0.01, respectively). Thus, mild MR had a detrimental effect on the exercise capacity in patients with dilated cardiomyopathy.

Adult↗

PubMed1997

Characterization of protein components of human urinary crystal surface binding substance.

We previously extracted crystal surface binding substance (CSBS) from human urine and showed that it appeared to constitute a substantial proportion of urinary macromolecular inhibitors of calcium oxalate crystallization. CSBS was isolated from human urine and fractionated by three consecutive chromatography procedures in order to characterize protein inhibitors of calcium oxalate crystallization. Sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and NH2-terminal amino acid sequencing revealed that inhibitory fractions eluted from a final, hydroxyapatite column contained prothrombin and osteopontin. Hydroxyapatite column fractions also contained other, unidentified protein inhibitors of calcium oxalate crystallization. CSBS contained also human serum albumin, alpha 1-acid glycoprotein, alpha 1-microglobulin, alpha 2-HS glycoprotein, retinol-binding protein, transferrin, and Tamm-Horsfall protein, but these proteins seemed to play no direct role in inhibitory activity.

Adult↗

PubMed1997

Performance study of a miniature gamma ray scintillation vivo probe for tumor localization.

UNLABELLED: We have developed a miniature gamma-ray endoscopic probe consisting of dual BGO detector probes for tumor detection inside the body cavities. The dual detector system was coupled with random coincidence to decrease the distant background radiation and to improve its spatial resolution for tumor localization. METHOD: The performance of the probe was investigated with a point source and a water phantom. A solution of positron emitting 18F isotope was used as the source. Clinical trials of the probe were done to localize tumors on the skin surface of four subjects carrying tumors close to the body surfaces, into whom 67Ga-citrate and 18F-FDG radiopharmaceuticals were injected. RESULTS: Measurements indicated that the spatial resolution of the dual detector probes is around 1.5 times better than the single detector probe, and both single and dual detector endoscopic probe systems are capable of localizing a tumor on a large photon background. CONCLUSION: The endoscopic probe may be easier to insert inside body cavities due to the small crystal size and the flexible light guides. A single detector probe with higher sensitivity may be useful in searching for tumors over a wide intracavity area but a dual detector probe can be used for precise tumor localization. The detector probe may also be suitable for intraoperative observation.

Adult↗

PubMed1997

Role of nitric oxide, prostaglandins and tyrosine kinase in vascular endothelial growth factor-induced increase in vascular permeability in mouse skin.

We investigated role of nitric oxide (NO), prostaglandins (PG) and tyrosine kinase in vascular endothelial growth factor (VEGF)-induced increase in vascular permeability in mouse skin. Subcutaneous injection of VEGF (0.5-2.0 ng/site) induced dose- and time-dependent increase in vascular permeability at the injection site determined by a leakage of Pontamine sky blue. VEGF (1 ng/site)-induced dye leakage was partially inhibited by N(G)-nitro-L-arginine methyl ester (an inhibitor for both constitutive and inducible NO synthase) (5 and 10 mg/kg, i.v.) and by aminoguanidine (a selective inducible NO synthase inhibitor) (5-20 mg/kg, i.v.), but not by an inactive enantiomer, N(G)-nitro-D-arginine methyl ester (10 mg/kg, i.v.). Pretreatment with an intraperitoneal injection of indomethacin (a nonselective cyclooxygenase inhibitor) (5 mg/kg) or N-(2-cyclohexyloxy-4-nitrophenyl) methanesulphonamide (a cyclooxygenase-2 selective inhibitor) (1-100 microg/kg) almost completely inhibited the effect of VEGF (1 ng/site). Coadministration of PGE2 (3 and 30 nmol/site) with VEGF did not restore the inhibitory effect of indomethacin on VEGF (1 ng/site)-induced increase in vascular permeability. Lavendustin A (a selective tyrosine kinase inhibitor) (10 and 50 microg/kg, s.c.) dose-relatedly inhibited the VEGF (1 ng/site)-induced increase in dye leakage, whereas its negative control, lavendustin B (10 microg/kg, s.c.) had no effect. Another tyrosine kinase inhibitor, genistein (2.5 mg/kg, s.c.) also inhibited the response. Cycloheximide (a protein biosynthesis inhibitor) (35 mg/kg, s.c.) suppressed the response of VEGF (1 ng/site). Histologically, no cellular infiltration was observed in the area of VEGF injection. These results suggest that increased vascular permeability induced by VEGF is mediated by local production of NO and arachidonic acid metabolites other than PGE2, which are most probably produced by inducible NO synthase and cyclooxygenase-2, respectively. Protein tyrosine kinase-mediated phosphorylation and synthesis of any new proteins are likely to be required in this effect of VEGF in mouse skin.

Animals↗

PubMed1997

Down-regulation of manganese-superoxide dismutase gene expression in idiopathic nephrotic syndrome.

An oxidant stress has been shown to prevail in experimental and clinical nephrotic syndrome. Such oxidant stress may be induced by a reduced activity of antioxidant systems. We examined the altered expression of manganese-superoxide dismutase (Mn-SOD), an antioxidant enzyme, in patients with idiopathic nephrotic syndrome, in whom an increased oxidant stress had been demonstrated. The Mn-SOD activities in peripheral blood mononuclear cells obtained from 12 patients with active nephrotic syndrome (6.0 +/- 1.1 years of age, mean +/- SE) and hypoproteinemia were 42% lower (p < 0.05) than in 12 control subjects (5.5 +/- 0.5 years of age) with normal serum total protein concentrations. Reverse-transcriptase polymerase chain reaction also demonstrated that Mn-SOD messenger RNA expression in the patients with nephrotic syndrome was, on average, 59% lower than in control subjects. Because expressions of some genes are sensitive to serum, the serum dependency of Mn-SOD gene transcription was studied in glomerular endothelial cells transfected with a luciferase reporter gene fused with a rat Mn-SOD DNA fragment of -806 to +22 bp of the transcription initiation site (-806:+22). When these cells were exposed to different concentrations of fetal bovine serum (0.5% to 15%), the transcriptional activities determined by luciferase activities were proportional to serum concentrations. This serum-dependent transcriptional activation was also demonstrated by the fragment (-220:+22) but not by the fragment (-220:-20). When glomerular endothelial cells transfected with the fragment (-220:+22) were treated with 5% serum from patients with active nephrotic syndrome, transcriptional activation was more than 80% less than that by 5% serum from control subjects without nephrosis. These results indicate that Mn-SOD gene transcription is regulated at least in part by serum, and that the serum-dependent transcription of the gene is diminished in patients with idiopathic nephrotic syndrome. The regulatory region of serum-dependent gene transcription resides within its early promoter region. Our findings suggest that down-regulation of antioxidant enzyme transcription may contribute increased oxidant stress in idiopathic nephrotic syndrome.

Animals↗

PubMed1997

Paradoxical positive nitrogen balance in burn patients receiving high-dose administration of insulin for nutritional care.

BACKGROUND: Nitrogen balance in patients who need high-dose administration of insulin has not been evaluated clinically. The purpose of this study was to compare the difference in nitrogen balance between burn patients who received high-dose administration of insulin and those who did not. METHODS: This study was performed in 19 severely burned adults with no liver or kidney failure. Patients were divided into two groups on the basis of the mean ratio of administered insulin and calorie intake (I/C) for the initial 4 weeks, a high I/C group (n = 9) and a low I/C group (n = 10). There were no significant differences between the two groups regarding age, percentage of area burned, and body weight. Nitrogen balance, blood urea nitrogen, and urine urea nitrogen were measured in all patients. Plasma concentrations of glucose, insulin, glucagon, cortisol, and urinary excretion of 3-methyl-histidine were measured in 12 patients (six in each group). RESULTS: Until day 10 both groups exhibited similar changes in plasma concentrations of glucose, insulin, glucagon, and cortisol. Subsequently, plasma concentrations of insulin and glucagon began to decrease in the low I/C group, whereas a high level was sustained in the high I/C group (p < 0.05). Plasma glucose and cortisol measurements showed no significant differences between the two groups. Blood urea nitrogen levels and urinary excretion of 3-methyl-histidine were not different between the two groups. Urine urea nitrogen excretion in the high I/C group, however, was significantly lower than that in the low I/C group from day 8 (p < 0.05). Thus the high I/C group achieved positive nitrogen balance more quickly than the low I/C group. Paradoxically, however, the high I/C group was at higher risk of septic complications and exhibited higher mortality than the low I/C group (p < 0.05). CONCLUSIONS: These results indicate that an improvement in nitrogen balance, which is accepted as a good thing in the management of critically ill patients, is not necessarily good in the high I/C group and that residual nitrogen was retained within the body in the high I/C group.

Adult↗

PubMed1997

A new engine-driven canal preparation system with electronic canal measuring capability.

A new cordless engine-driven root canal preparation system has been developed that electronically monitors the location of the file tip and the torque applied to the file during all instrumentation procedures. The Root ZX is mounted inside the handpiece to measure the canal length. The engine is driven with a rechargeable battery, and it works more than 40 minutes without a recharge. Nickel-titanium files are used for this preparation system. The file is rotated at 240 to 280 rpms. When the file tip reaches the apical constriction, the revolution of the file can be automatically reversed (Auto-apical-reverse mechanism). If there is too much torque, the rotation is automatically reversed (Auto-torque-reverse mechanism). These automatic functions promise a safer engine preparation of the canal with nickel-titanium files.

Dental Alloys↗

PubMed1997

Mesangial phenotypic changes associated with cellular lesions in primary focal segmental glomerulosclerosis.

Injury to glomerular visceral epithelial cells has been proposed as the initial step in glomerular scar formation in primary focal segmental glomerulosclerosis (FSGS); however, the subsequent process that ultimately results in glomerular scar formation remains uncertain. This study examined whether phenotypically altered mesangial cells determine the early progression of primary FSGS. Cellular lesion characterized by proliferative epithelial cell reaction with occasional endocapillary hypercellularity has been considered to be an early morphologic feature in the development of glomerular scar in primary FSGS. We compared the immunohistologic findings of 10 patients with primary FSGS showing cellular lesion, 15 patients with primary FSGS showing only segmental scar, and 10 patients with minimal-change nephrotic syndrome. Histologically normal kidney tissue samples obtained from three patients with renal trauma were used as normal controls. Alpha-smooth muscle actin expression detected by a mouse anti-human monoclonal antibody as well as de novo type III collagen expression determined by a goat polyclonal antibody were prominent in the glomerular tufts with cellular lesions in FSGS patients. A significant increase in the number of glomerular CD68+ (a mouse anti-human monoclonal antibody) macrophages was also observed in association with the cellular lesion. Repeat renal biopsies in six of the 10 FSGS patients with a cellular lesion showed disappearance of the cellular lesion, reduced glomerular alpha-smooth muscle actin expression, decreased number of glomerular CD68+ macrophage, and progression of glomerular scar formation. These results indicate that mesangial cells undergo phenotypic changes to myofibroblasts in association with the cellular lesion in primary FSGS. Thus, the phenotypically altered mesangial cells acquiring features of a myofibroblast may have an important role in the early process of glomerular scar formation in certain types of primary FSGS.

Actins↗

PubMed1997

Burn injuries in the 1995 Hanshin-Awaji earthquake.

In the 1995 Hanshin-Awaji earthquake, 504 deaths were listed as fire related, although many of the victims may have been crushed or suffocated before they were burned. Census data related to surviving burn victims, however, were unknown. This study was designed to examine the medical requirements of those burn patients following the earthquake. Medical records of 2718 patients with injuries admitted to 95 hospitals during the 15 days after the earthquake were retrospectively reviewed. Only 44 patients (1.9 per cent) were hospitalized with burns. Scalds with less than 20 per cent total burn surface area (TBSA) were mainly observed; flame burns from earthquake-associated fires were rare. Morbidity rates increased in patients over 40 years old. Associated injuries were observed in 11 cases. These included three soft tissue injuries, one rib, three spine, three pelvis and two extremity fractures, and two cases of crush syndrome. Intensive care was required for only 10 patients, five of whom were transferred to hospitals that were undamaged or outside the earthquake zone. No relationship was noted between the number of burned houses and that of hospitalized burn patients. These results suggest that the number of burn patients requiring medical care was less than might have been expected in view of the total number of fire-related deaths in this urban earthquake.

Burns↗

PubMed1997

Quantitative subtraction with direct digital dental radiography.

OBJECTIVES: To elucidate the accuracy in vitro of quantitative digital subtraction for direct digital dental radiography using a commercially available image analysis system. METHODS: Images were corrected first for dark current and sensitivity variation among pixels of the CCD sensor (first correction), and corrected further for interimage variations due to the variations in exposure conditions (second correction). A copper stepwedge with six steps was used in the second correction. Three corrected images derived from three original images at each different exposure time were examined to confirm the reliability of the second correction. Correlation between bone mineral content and pixel value was assessed in subtracted images of an artificial bone phantom. RESULTS: The first and second corrections significantly improved the intra- and inter-image variation respectively. The second corrected images obtained at three different exposure times showed almost the identical grey levels. An original image was transformed to a copper equivalent image with a high reliability by our original method. The pixel value in the subtracted image between two copper equivalent images of a bone phantom was linearly related to the bone mineral content. There was a slight overestimate at lower pixel values but it was accurate at higher pixel values. CONCLUSIONS: Quantification of digital subtraction using this method is sufficiently reliable for its application to clinical practice to be evaluated.

Adult↗

PubMed1997

Interleukin-6 secreting phaeochromocytoma associated with clinical markers of inflammation.

Phaeochromocytomas have been shown to produce not only catecholamines but other neuropeptides and hormones, with a variety of clinical manifestations. We report a 70-year-old female patient with phaeochromocytoma exhibiting sustained hypertension, low-grade fever, thrombocytosis, and elevated levels of plasma fibrinogen and C-reactive protein. Serum interleukin (IL)-6 levels were significantly elevated, whereas serum IL-1 alpha and IL-1 beta were not detectable. After surgical removal of the tumour, hypertension and low-grade fever disappeared, and the laboratory finding including serum IL-6 concentrations became normal. Immunohistochemical study of the tumour showed positive staining for IL-6. Culture of the resected tumour revealed the production of large amounts of IL-6. It is suggested that IL-6 secreted by the tumour was responsible for some of the clinical manifestations in this patient.

Adrenal Gland Neoplasms↗

PubMed1997

Glycosaminoglycans in crystal-surface binding substances and their role in calcium oxalate crystal growth.

OBJECTIVE: To clarify the role of glycosaminoglycans (GAGs) in crystal-surface binding substances (CSBS) on the growth of calcium oxalate crystals in urine. MATERIALS AND METHODS: Urine samples (24 h) were collected from healthy men (aged 25-42 years) and CSBS were obtained from the pooled urine samples. The CSBS were digested with heparitinase or proteinase and the inhibition of crystal growth assessed before and after enzyme digestion. Anion-exchange chromatography and high-performance liquid chromatography (HPLC) were used to determine the types of GAGs contained in the CSBS. RESULTS: The inhibitory activity of CSBS on crystal growth decreased with concentration when digested with heparitinase or proteinase. HPLC showed that CSBS contained a small amount of dermatan sulphate and abundant heparan sulphate, both of which inhibited crystal growth. CONCLUSION: Both heparan sulphate and dermatan sulphate may inhibit calcium oxalate crystallization, the former being the predominant GAG in CSBS.

Adult↗

PubMed1997

CT, MR imaging and muscle biopsy in severe crush injury.

PURPOSE: We reviewed CT and MR findings in crush injuries in muscles and compared them with findings at muscle biopsy. MATERIAL AND METHODS: CT and MR examinations were made of the lower extremities in 6 adult patients whose muscles were crushed in the big earthquake in Kobe, Japan, on 17 January 1995. All CT examinations were performed twice and within 60 days of the earthquake. In 5 of the 6 patients, biopsies were taken of the injured muscle after the CT and MR examinations. RESULTS: At CT investigation, the images in 5 patients showed calcification in the muscles, and the crushed muscle appeared atrophic. In 3 of these 5, the degree of calcification decreased with time. At MR investigation, T1-weighted images of the crushed muscle showed isointensity in 4 of the 6 patients and high intensity in the remaining 2. T2-weighted images of the crushed muscle showed inhomogeneous high intensity in all patients. After Gd injection, all the crushed muscles were enhanced, either slightly or markedly. At muscle biopsy, in 5 of the 6 cases, the findings showed calcification in the muscle cells and the total destruction of the normal muscle structure. CONCLUSION: CT and MR findings in crush injury correlated well with the findings at histopathology.

Acute Disease↗

PubMed1997

Inhibition by 1-aminocyclobutane-1-carboxylate of the activity of 1-aminocyclopropane-1-carboxylate oxidase obtained from senescing petals of carnation (Dianthus caryophyllus L.) flowers.

We partially purified 1-aminocyclopropane-1-carboxylate (ACC) oxidase from senescing petals of carnation (Dianthus caryophyllus L. cv. Nora) flowers and investigated its general characteristics, and, in particular, the inhibition of its activity by ACC analogs. The enzyme had an optimum pH at 7-7.5 and required Fe2+, ascorbate and NaHCO3 for its maximal activity. The Km for ACC was calculated as 111-125 microM in the presence of NaHCO3. Its M(r) was estimated to be 35 and 36 kDa by gel-filtration chromatography on HPLC and SDS-PAGE, respectively, indicating that the enzyme exists in a monomeric form. These properties were in agreement with those reported previously with ACC oxidases from different plant tissues including senescing carnation petals. Among six ACC analogs tested, 1-aminocyclobutane-1-carboxylate (ACBC) inhibited most severely the activity of ACC oxidase from carnation petals. ACBC acted as a competitive inhibitor with the Ki of 20-30 microM. The comparison between the Km for ACC and the Ki for ACBC indicated that ACBC had an affinity which was ca. 5-fold higher than that of ACC. Whereas ACC inactivated carnation ACC oxidase in a time-dependent manner during incubation, ACBC did not cause the inactivation of the enzyme. Preliminary experiments showed that ACBC and its N-substituted derivatives delayed the onset of senescence in cut carnation flowers.

Amino Acid Oxidoreductases↗

PubMed1997

Analysis of 372 patients with Crush syndrome caused by the Hanshin-Awaji earthquake.

OBJECTIVE: To clarify clinical features and determine the severity of injuries in patients with crush syndrome in Hanshin-Awaji earthquake. METHODS: We retrospectively reviewed medical records of 6,107 patients hospitalized in 95 hospitals, and identified 372 patients with crush syndrome. RESULTS: The major sites of crush injury were in the lower extremities (74%), followed by the upper extremities (10%), and the trunk (9%). Pelvic fractures, limb fractures, and abdominal injuries were the most frequently associated injury. Patients with trunk compression and/or with abdominal injury had a higher mortality rate. A total of 50 patients (13.4%) died. The causes of death within 5 days after the earthquake were hypovolemia and hyperkalemia. Peak serum creatine kinase concentration increased with the number of crushed extremities. Mortality and the risk of acute renal failure were higher in patients with creatine kinase concentration more than 75,000 micro/L. CONCLUSIONS: Peak serum concentration of creatine kinase as well as the number of injured extremities serve to estimate the severity of crush syndrome.

Abdominal Injuries↗

PubMed1997

Fluid resuscitation and systemic complications in crush syndrome: 14 Hanshin-Awaji earthquake patients.

BACKGROUND: Crush syndrome is a form of traumatic rhabdomyolysis characterized by systemic involvement, in which acute renal failure is potentially life-threatening. METHODS: Clinical and laboratory data of 14 crush-syndrome patients transferred to a tertiary emergency department after the Hanshin-Awaji earthquake were analyzed. The patients were buried under collapsed houses for the average of 6.7 +/- 5.7 (SD) hours (range, 1 to 24 hours). They were referred to us 6 to 250 hours after the earthquake. RESULTS: Of those who arrived at our institution within 40 hours, 25% (two of eight) developed renal failure, whereas all six patients who arrived after 40 hours developed renal failure. Peak serum creatine kinase ranged from 6,677 to 134,200 U/L (51,674 +/- 41,776). Renal failure was highly associated with massive muscle damage (serum creatine kinase above 25,000 U/L) and insufficient initial fluid resuscitation (below 10,000 mL/2 days). CONCLUSIONS: Prompt and adequate, if not massive, fluid resuscitation is the key to preventing renal failure after such injury.

Creatine Kinase↗

PubMed1997

Analysis of 2,702 traumatized patients in the 1995 Hanshin-Awaji earthquake.

BACKGROUND: This study was undertaken to define the factors that affected the final outcome of trauma patients in the Hanshin-Awaji earthquake. METHODS: Medical records of patients admitted to 95 hospitals within or surrounding the affected area during the first 15 days after the quake were reviewed. RESULTS: There were 2,702 traumatized patients. One-third of the patients were transported to hospitals in the surrounding area and had a mortality rate of 3%. The remainder, who were treated in the affected hospitals, showed a significantly higher mortality rate (8%; p < 0.05). Intensive care was provided for 513 patients, most of whom suffered from crush syndrome or from injuries to vital organs; these patients had a high mortality rate. Patients with other types of injuries had a lower mortality rate. CONCLUSION: Crush syndrome and injuries to vital organs were potentially life-threatening. We believe that early transportation of such patients to undamaged hospitals with the ability to provide intensive care would have improved the survival rate.

Abbreviated Injury Scale↗

PubMed1997

Prolidase activity in chronic wound and blister fluids.

We investigated prolidase activity in samples derived from wound fluid as well as blister fluid. Prolidase activity was elevated in fluid samples collected from wounds over the levels in sera collected from patients with chronic wounds (P < 0.05). Prolidase activity was also present in samples taken from blister diseases. However, prolidase activity in blister fluid was not higher than that in sera collected from patients with blister diseases. Our results indicate that prolidase may play a role in wound healing.

Adult↗