Biomedical subjects

Y Yoshida

Publications and source records attributed to Y Yoshida.

At least 847 records · Page 47Linked to original sources

PubMed1993

Urine, serum and hair monitoring of hydrofluoric acid workers.

To define the relationship between fluoride (F) concentration in the serum, urine and hair of workers and the concentration of hydrofluoric acid (HF) in the work environment, pre- and postshift serum and urine samples of 142 HF exposed workers and 237 unexposed workers were examined. Hair specimens were also collected for the determination of F. To determine whether external contamination influences hair analysis, the control hair samples were kept in the work environment for one week. The pre-exposure levels in serum and urinary F in HF workers were higher (P < 0.01) than the control values. This suggests that F excretion from the body continues for at least 12 hours. The postshift serum and urinary F concentrations of these workers were significantly higher (P < 0.01) than the preshift concentrations. The levels of F in the hair of HF workers were also higher than in the control subjects. The concentrations of F in postshift serum and urine, and hair were in good correlation to each other. There was a linear relationship between mean serum and urinary F concentrations and HF concentration in the workplace. A mean F concentration of 82.3 micrograms/l in serum and 4 mg/l in urine with a lower fiducial limit (95%, P = 0.05) of 57.9 micrograms/l in serum and 2 mg in urine were estimated to correspond to an atmospheric HF concentration of 3 ppm, which is the maximum allowable concentration recommended by Japan Association of Industrial Health and also the threshold limit value suggested by American Conference of Governmental Industrial Hygienists.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

Phase II study of NK313 in malignant lymphomas: an NK313 Malignant Lymphoma Study Group trial.

Liblomycin (NK313) is a bleomycin analog that has proved to be associated with less pulmonary toxicity and with more potent antitumor activity than bleomycin in animal tumors. In a phase I study, pulmonary toxicity was not observed, whereas myelosuppression was the dose-limiting factor. The maximum tolerated dose was 140 mg/m2 given once a week for 4 weeks. In the present phase II study, patients with malignant lymphomas received liblomycin at 80 or 100 mg/m2 by intravenous infusion over 15 min once a week for 4 weeks. A total of 39 patients were entered, and 31 [4 with Hodgkin's disease (HD) and 27 with non-Hodgkin's lymphoma (NHL)] were evaluable. The median age of the patients was 52 years (range, 22-74 years), and their performance status ranged from 0 to 3. In all, 28 of the patients had a history of intensive anticancer chemotherapy. Responses were evaluated according to WHO criteria. We obtained 1 complete remission and 9 partial remissions (PRs), for an overall response rate of 37%, in the 27 patients with NHL, whereas 1 PR was achieved in the 4 patients with HD. In all, 9 PRs (32.1%) were obtained in patients who had been exposed to prior chemotherapy, including 4 PRs (33.3%) in 12 patients who had previously been treated with bleomycin. Myelosuppression and nausea and vomiting were the major toxicities, which occurred in about 50% of the patients, and myelosuppression was severe in two patients treated at a dose of 100 mg/m2. We concluded that liblomycin demonstrated significant antitumor activity against malignant lymphomas.

Adult↗

PubMed1993

Depolymerization of hyaluronan by sonication.

High molecular weight hyaluronan (M(r) 400,000) obtained from human umbilical cord was depolymerized by sonication for 10 h into small molecules and finally into molecules of constant size (M(r) 11,000). The molecular size of the depolymerized hyaluronan was unaltered even under different conditions of sonication. After sonication, the main sugar residues at the reducing and non-reducing termini of depolymerized hyaluronan were N-acetylglucosamine (86%) and glucuronic acid (98%), respectively. Hyaluronans derived from rooster comb (M(r) 1 x 10(6)) and Streptococcus zooepidemicus (M(r) 1.2 x 10(6)) were depolymerized into molecules of different but characteristic sizes by sonication. On the other hand, neither chondroitin sulfate nor glycogen was depolymerized by sonication. These results suggest that high molecular weight hyaluronan may have some weak linkages related to N-acetylglucosamine in the chain, which are extremely sensitive to sonication. At present, however, the nature of these linkages is still unclear.

Animals↗

PubMed1993

pH profile of esophagus in patients with inlet patch of heterotopic gastric mucosa after tetragastrin stimulation. An endoscopic approach.

In a series of 1771 endoscopic examinations from 1988 to 1990, we observed 62 cases (3.3%) of inlet patch of heterotopic gastric mucosa (IPHGM) in the upper esophagus. Ten of the IPHGM patients complained of throat discomfort or globus sensation, and these symptoms were relieved by histamine H2-antagonists, suggesting that these symptoms could be caused by acid secretion from IPHGM. Acidity under tetragastrin stimulation was measured in the esophagus and compared with the pool of gastric juice and saliva under direct vision by a newly devised endoscopic method. Congo red staining was also carried out after pH measurement. Significant pH reduction at IPHGM was observed in three cases, and black coloration with Congo red staining in the IPHGM was observed in four cases. These findings suggest that IPHGM is a mucosal change with latent acid secretion.

Adult↗

PubMed1993

Diagnosis of cardiac thrombosis in patients with atrial fibrillation in the absence of macroscopically visible thrombi.

Cardiac thrombosis due to atrial fibrillation (AF) has been recognized as the most common cause of cerebral embolism. However, sometimes no macroscopic thrombus is found at autopsy in the heart of a victim of this type of cerebral embolism. We investigated morphological changes in the left atrial endocardium of 31 patients (including 21 cases with AF) who had died of cerebral embolism. "Rough endocardium" (RE) seen macroscopically provided evidence for the existence of atrial thrombosis. The RE that appeared in AF cases was due to a granular and wrinkled appearance of the endocardium associated with oedematous and fibrous thickening. Fibrin-thread deposits were also always distinguishable. Mural thrombi and oedema with neutrophil infiltration in the subendocardium could be seen under the microscope. Small areas of endothelial denudation and thrombotic aggregations were commonly observed by scanning electron microscopy (SEM). These SEM lesions were significantly more frequent in cases with AF than in controls (P < 0.001). The diagnostic success rate for atrial thrombosis among cases with AF increased from 33.3% to 81% when thrombi proven by histological investigation of the areas with RE were added. Left atrial RE may be an anatomically relevant finding for the existence of atrial thrombosis with AF, when the thrombosis cannot be detected upon gross observation at autopsy.

Adult↗

PubMed1993

Serial changes in endogenous erythropoietin levels in patients with myelodysplastic syndromes and aplastic anemia undergoing erythropoietin treatment.

Recombinant human erythropoietin (rhEpo) was administered to 14 patients with myelodysplastic syndrome (MDS) and seven patients with aplastic anemia (AA). In 19 patients, doses of 6000 units were given intravenously three times a week (t.i.w.) with the dose being doubled up to 24,000 units every 8 weeks until a response was obtained. RhEpo was given subcutaneously in two patients. Seven patients, four with MDS and three with AA, showed a significant response with an increase of hemoglobin concentration during therapy. The response occurred at doses of 12,000 units in five and 24,000 units in two patients. Responding patients with both MDS and AA had a relatively low serum Epo (s-Epo) level prior to Epo therapy. MDS responders had either refractory anemia (RA) or RA with ring sideroblasts (RARS), while two of the Epo responders in AA had a severe form of the disease. However, since some of the Epo responders had a high initial s-Epo concentration, a high s-Epo level does not preclude the use of rhEpo. Serial determination of s-Epo levels showed a progressive decline in six of the seven responders even when they were on rhEpo therapy, while the s-Epo levels remained elevated or further increased with time in most nonresponders. RhEpo was well tolerated by all patients. The results suggest that rhEpo is a safe and effective treatment for a certain proportion of patients with MDS and AA. Moreover, serial determination of s-Epo during therapy may be useful in monitoring and predicting the therapeutic effect of rhEpo.

Adolescent↗

PubMed1993

Detection of focal nodular hyperplasia of the liver with color Doppler ultrasonography.

A 3-cm lesion indicative of focal nodular hyperplasia (FNH) of the liver was coincidentally detected in a 21-year-old female. Ultrasonography (US), computed tomography (CT), magnetic resonance (MR) imaging and liver scintigraphy all proved nonspecific. However, color Doppler US demonstrated characteristic vascular patterns of FNH of the liver, including (a) hypervascularity of the mass, (b) an enlarged afferent blood vessel in the tumor with blood flow toward the center of the tumor, and (c) arterial pulse waves in all the vessels in the lesion, detected by means of the fast Fourier transformation (FFT). With selective hepatic angiography, a "spoke-wheel" pattern was revealed. The angiographic pattern corresponded well to that shown by color Doppler US. On the basis of the findings from these two modalities, the diagnosis of FNH was made. This report examines the effectiveness of color Doppler US in the differential diagnosis of FNH, compared with other imaging modalities.

Adult↗

PubMed1993

Negative feedback regulation of acid secretion: linkage of acid secretion and mucosal defense.

To regulate inappropriate or excessive acid secretion that may be harmful not only to surrounding mucosal cells but also parietal cells themselves, versatile mechanisms operate to control acid secretion. In this article elaborate mechanisms that participate in the control of acid secretion are described with our data and a review of relevant findings in the literature concerning the action or secretion of key regulatory molecules. The analysis of the regulatory mechanisms revealed that appropriate secretory control can be achieved by multiple feedback regulations, which are closely coordinated with mucosal defense. In the feedback circuits, the regulatory factors cannot be simply categorized into either aggressive or defensive factors. Therefore we propose that the mucosal integrity and tissue homeostasis would be better understood by a feedback loop model rather than by a dualistic balance model.

Animals↗

PubMed1993

Endoscopic ultrasonographic (EUS) evaluation of the quality of gastric ulcer healing.

EUS provides cardinal tomographic findings of gastric ulcer such as low echo mass (ulcer echo), thickening of the wall, a symmetrical or asymmetrical convergence of the submucosal layer, and a sharp (pin-point) or blunt (broad-surface) convergence, variously expressed in accordance with the depth or width, and also with the history of recurrence of ulcer. A low echo mass, or an ulcer echo histopathologically consists of fibrosis and granulation, sonographically correlating well with the thickening of the wall. Seventy nine cases of ulcer scar, 52 of which were evaluated endoscopically as S1 (red scar) and 27 as S2 (white scar), were scanned by EUS. The incidence of high quality healing recognized on EUS with complete disappearance of a low echo mass and subsidence of the wall thickness was 21.2% (11 of 52 ulcer scars) in the S1 stage group, which remarkably increased up to 70.4% (19 of 27) in the S2 group (P < 0.01). The results indicate a definite correlation between endoscopic and EUS assessment of an ulcer scar state. The cumulative relapse rate at 12 months during maintenance therapy with half doses of H2 blocker was found to be 4.5% (1 of 22 cases) in the group with high quality healing on EUS, 40.9% (9 of 22) in the group with fair quality healing, and 75.0% (12 of 16) in the group with poor quality healing. The results of the present study suggest that EUS assessment may be a reliable and objective predictor of susceptibility to ulcer recurrence, accurately evaluating the quality of gastric ulcer healing.

Gastroscopy↗

PubMed1993

Exercise coronary flow reserve of bilateral internal thoracic artery bypass grafts.

We attempted to quantify the exercise coronary flow reserve in 20 patients with bilateral internal thoracic artery grafts to the left coronary arteries (group I) who had complete revascularization. The coronary sinus blood flow was measured by the continuous thermodilution method both at rest and during exercise (50 W for 8 to 9 minutes) approximately 1 month after the operation. These results were compared with 30 patients treated with an internal thoracic artery and saphenous vein grafts to the left coronary arteries (group II) and 9 patients with saphenous vein grafts alone to the left coronary arteries (group III). There were no differences among the three groups in age, sex, number of vessels involved, heart rate, double products, left ventricular (LV) end-diastolic pressure, LV ejection fraction, LV end-diastolic volume, or LV mass at the time of study. None of the 59 patients in the study had abnormally enlarged LV end-diastolic volume or increased LV mass. The postoperative coronary sinus blood flow per 100 grams of LV mass at rest was similar among the three groups (73.0 +/- 28.4 mL/min per 100 g LV mass in group I, 73.4 +/- 31.1 mL/min per 100 g LV mass in group II, and 75.9 +/- 28.5 mL/min per 100 g LV mass in group III [not significant]) and significantly (p < 0.01) increased by exercise, although the differences between groups during exercise were not significant (158.9 +/- 45.9, 153.5 +/- 72.1, and 148.3 +/- 60.0 mL/min per 100 g LV mass, respectively [not significant]).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗

PubMed1993

Benefits of posttransplantation monitoring of interleukin 6 in lung transplantation.

To determine the predictive diagnostic value of interleukin 6 (IL-6) monitoring in lung and heart-lung transplants, we measured posttransplantation serum IL-6 levels in 17 adult lung or heart-lung transplant recipients. Posttransplantation IL-6 elevation patterns were classified into 4 groups: serum IL-6 level remained negative throughout the monitoring period (group 1; n = 1; 6%); several sharp spikes with normal baseline (group 2; n = 9; 53%); persistently high level of serum IL-6 (group 3; n = 3; 18%); and several sharp spikes of serum IL-6 elevation with abnormally high baseline (group 4; n = 4; 24%). One patient without an elevation of IL-6 (group 1) did not experience any episodes of rejection or infection. Nine patients in group 2 had 19 IL-6 spikes, 13 of which were associated with histopathologically or clinically diagnosed rejection, 3 with acute bronchitis, and 1 with diffuse alveolar damage. Three patients in group 3 had persistent infections including cytomegalovirus infection, toxic megacolon, and repeated bacterial infection during the monitoring period, and 4 in group 4 died within 3 months after transplantation. From this study it appears that a spiked elevation of IL-6 could have a predictive value in diagnosing rejection, and persistently high levels of IL-6 indicate the presence of infection. Thus, IL-6 monitoring is beneficial for lung transplant recipients.

Adult↗

PubMed1993

Three cases of juvenile onset HTLV-I-associated myelopathy with pseudohypoparathyroidism.

Among 201 patients diagnosed with HAM/TSP at Kagoshima University, 21 juvenile onset patients had manifested clinical signs and symptoms at less than 15 years of age. They appeared to have common characteristics such as short stature and slight mental retardation. These signs prompted us to investigate five of them endocrinologically; and three patients with pseudohypoparathyroidism (PHP) were confirmed. Serum calcium levels were low, and human parathyroid hormone (PTH) infusion (Ellsworth-Howard test) caused low response in urinary cyclic AMP and phosphorus excretion. The first case had IgA nephropathy, which is generally associated with infectious diseases, while the second case had muscular lymphocytic infiltration. The mothers of cases 1 and 2, who were both seropositive for HTLV-I, were suspected to have abnormal calcium metabolism based on Ellsworth-Howard test. A brother of case 1 and two sisters of case 3 had also HAM/TSP and short stature. The early clinical onset of HAM/TSP may be due to PTH receptor anomaly and a low level of 1,25-dihydroxyvitamin D, which is deficient in PHP and is involved in the regulation of the immune response. The association with IgA nephropathy or myositis may result from progressive HTLV-I infection.

Adult↗

PubMed1993

Nucleolar organizer regions are independently associated with a shortened survival in patients with non-small cell lung cancer.

We examined nucleolar organizer regions (Ag-NOR) in 102 patients with non-small cell lung cancer (NSCLC). Ag-NOR counts were generally higher in tumours from more advanced stages, or in poorly differentiated adenocarcinomas. Six potential-prognostic indicators included sex, age, year of operation, histology, stage and Ag-NOR count. Stage and Ag-NOR counts had a significant prognostic value in the univariate analysis for 79 patients who died of their lung cancer. In the multivariate analysis, high Ag-NOR counts as well as disease stage were independently associated with a poor prognosis. Furthermore we divided patients into three groups according to their Ag-NOR counts and found that in patients with stage I and II disease higher Ag-NOR counts were associated with shortened survival. This trend did not continue in patients with stage III and IV disease.

Adenocarcinoma↗

PubMed1993

Distribution of SP- and CGRP-immunoreactivity in the cat's larynx.

The distribution of substance P (SP) and calcitonin gene-related peptide (CGRP) immunoreactive (ir) fibres in the cat's larynx was investigated utilizing immunohistochemistry. Many SP- and CGRP-ir fibres with varicosities were found within and below the epithelium and along the basement membrane of the mucosa of all different regions except in the membranous portion of the vocal fold. In the subepithelium, some SP- and CGRP-ir nerve bundles and nerve fibres were recognized around the vessels and glands. In the mucosa, the pattern of distribution and the density of SR-ir fibres were similar to those of CGRP-ir fibres. These reactive fibres were denser in the supraglottic region than in the subglottic region. In the taste bud-like structures, only SP-ir fibres appeared, whereas in the motor endplates, CGRP-reaction was found exclusively. The present findings suggest that the regional distribution of SP- and CGRP-immunoreactivity might be related with sensory and autonomic innervation in the larynx.

Animals↗

PubMed1993

CGRP-immunoreactive cells supplying laryngeal sensory nerve fibres in the cat's nodose ganglion.

Through a combination of retrograde staining by wheat germ agglutinin (WGA) and immunohistochemistry, calcitonin gene-related peptide (CGRP)-reactive sensory neurons projecting from the laryngeal mucosa were detected in the feline nodose ganglion. The size of the CGRP-immunoreactive cell which was regarded as a laryngeal sensory neuron, was about 60 microns in diameter: the shape of the immunoreactive laryngeal sensory neuron was unipolar. CGRP-reacted laryngeal sensory cells were found in the rostral part of the nodose ganglion extending to the middle part. They aggregated in the most rostral part, were sparse in other parts and were approximately 50 per cent of WGA-reactive laryngeal sensory neurons in number. Our results suggest that this neurotransmitter might play an important role in laryngeal peripheral sensory innervation.

Animals↗

PubMed1993

Binding of an intrinsic ATPase inhibitor to the interface between alpha- and beta-subunits of F1FoATPase upon de-energization of mitochondria.

Yeast mitochondrial F1FoATPase has three regulatory subunit proteins: ATPase inhibitor, 9K protein, and 15K protein. Mutant yeasts lacking one or more of these protein factors were constructed by gene disruption [Ichikawa, N. et al. (1990) J. Biol. Chem. 265, 6274-6278; Yoshida, Y. et al. (1990) Eur. J. Biochem. 193, 49-53]. Dissipation of the electrochemical potential of protons of the mitochondrial inner membrane by an uncoupler or by a combination of valinomycin and potassium ions induced ATP-hydrolyzing activity of F1FoATPase in mitochondria of all the mutants, as in those of wild-type cells. However, the ATPase activity was inactivated within a minute in normal mitochondria, but was not suppressed in inhibitor-deficient mitochondria, and in mitochondria lacking either 9K or 15K protein, the inactivation of ATPase was slow and incomplete. Covalent binding of inhibitor protein to the enzyme was achieved with a zero length cross-linker, EEDQ, in uncoupled normal mitochondria, in which the inhibitor linked directly to both the alpha- and beta-subunits. This result strongly suggests that the binding site of the inhibitor protein is located at the interface between the two subunits.

Adenosine Triphosphate↗

PubMed1993

Age-related changes in the microvessels of the human stomach: an ultrastructural study.

The ultrastructure of microvessels in the gastric mucosa of patients with atrophic gastritis was investigated. In the gastric mucosa of atrophic gastritis, the endothelial cells of microvessels were irregularly swollen and subendothelial spaces were enlarged. The basement membrane underlying the endothelium was thickened. Degeneration of smooth-muscle cells was also evident in the media. These changes appear to correspond to sclerosis or aging of the microvessels. Such sclerotic changes in microvessels may initiate deterioration of the microenvironment in the gastric mucosa and may consequently affect metabolic activity of the gastric mucosal cells. Those sequences might induce degeneration or abnormal differentiation of mucosal cells. Such vascular changes may advance slowly and increase in intensity with advancing age. The final result would be the histologic changes associated with atrophic gastritis.

Aged↗

PubMed1993

Histologic differentiation and motility of rat stomach.

An ultrastructural and immunohistochemical study was done to investigate the normal developmental process of rat gastric wall. Neuronal processes were observed on the external side of immature muscle cells on gestational day 15, and Auerbach's plexus was found on gestational day 18, after which neuronal elements extended just under the subepithelial area. Myofilaments appeared in undifferentiated mesenchyme cells on gestational day 15. On day 17, stomach was responsive to Ach stimulation. On the day after the initiation of gastric motility, gastric glands started to form on the mucosal surface. At the same developmental stage, some parts of the mucosal epithelium and the submucosal connective tissues were stained with antiserum against tenascin. Endocrine and parietal cells appeared in the mucosal epithelium on gestational day 19. Dense secretory granules on the apical surface of mucosal epithelium were increased between day 20 and 21. The cytoplasmic organelles gradually developed with advancing fetal age. We suggest that tenascin may play a role in gastric gland formation and that there are some relationships between gastric gland formation and gastric motility. We believe that the development of subepithelial tissues may be closely associated with epithelial growth.

Animals↗