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Biomedical subjects

H Tada

Publications and source records attributed to H Tada.

At least 307 records · Page 17Linked to original sources
PubMed1991

Nifedipine-induced gingival hyperplasia: a clinical and in vitro study.

Two cases of gingival hyperplasia associated with long-term administration of nifedipine, a drug that dilates coronary arteries, are reported. The clinical and histopathological features of the gingival hyperplasia induced by nifedipine were similar to those induced by phenytoin, an anticonvulsant drug. In the present cases, gingival inflammation had developed before drug administration. In one case, extensive dental plaque control in addition to surgical removal of the overgrown gingival tissues resulted in satisfactory progress without the need to discontinue drug administration, suggesting that the preexisting gingival inflammation was involved in the development of this periodontal disease. In the other case, change from nifedipine to another drug resulted in spontaneous recovery, strongly suggesting that the drug had induced the gingival hyperplasia. Nifedipine had no direct effects in vitro on proliferation or collagen synthesis of gingival fibroblastic cells from one of the patients. Study of these two cases suggests that both local inflammatory factors and long-term administration of nifedipine were responsible for the gingival hyperplastic changes observed.

Cell Division↗
PubMed1991

Interaction of ascorbic acid and glucose on production of collagen and proteoglycan by fibroblasts.

Collagen and proteoglycans are two major constituents of the extracellular matrix, and their abnormalities have been incriminated in the pathogenesis of diabetic complications. A decrease of plasma ascorbic acid has been reported in diabetes and thus may play a role in the collagen and proteoglycan abnormalities in diabetes. Ascorbic acid and glucose share structural similarity, and their metabolism may interact at the level of membrane transport and cellular action. In this study, we used a fibroblast culture system to explore this possibility. Ascorbic acid increased collagen and proteoglycan both in the culture medium and the cell layer. This stimulatory action of ascorbic acid was inhibited by the presence of glucose at a concentration of 25 mM. The effect of high glucose concentration was not mediated by inhibition of ascorbic acid uptake by fibroblasts. Insulin is able to abolish this inhibitory action of glucose on collagen production, but the precise mechanism is unclear. These results show that the high glucose concentration in diabetes can impair the action of ascorbic acid at the cellular level. This may further accentuate the problem of decreased availability of this vitamin as a result of its low plasma concentration.

Amino Acids↗
PubMed1991

[The role of surgery in the treatment of chronic empyema].

For the last ten years we had 56 patients operated for the empyema which occupied almost all the thoracic cavity. We evaluated their postoperative pulmonary functions and their sequelae. The pathological features of the resected lung and empyema wall were also examined. Surgical procedures consisted of 25 extraperiostal air plombage, 14 pleuropneumonectomy, 8 decortication, and 9 other procedures (lobectomy, muscle-flap, omental flap, and others). Preoperative %VC of patients with extraperiostal air plombage, those with pleuropneumonectomy, those with decortications and those with other procedures were 59.6 +/- 12.6, 46.4 +/- 11.1, 63.0 +/- 10.1, and 53.8 +/- 11.7 respectively. Of 11 patients who developed severe respiratory impairments (%VC less than 40 and/or FEV 1/VC predicted less than 30) post operatively, 4 had extraperiostal air plombage, 4 had pleuropneumonectomy, and 3 had other procedures. In general, degree of respiratory impairment was more severe in patients who underwent multiple surgical procedures. Of 18 patients who survived 5 years or more, %VC was under 50% in 9, and of those nine patients five had 30% decrease in VC compared to the preoperative values and there were 2 patients with extraperiostal air plombage in whom extreme shrinkage and deformity of hemithorax were observed though they had neither additional surgeries nor recurrences. Hemangioma was often seen on the walls of empyema and in some they became so large as to cause mediastinal shift. There were patients with round atelectasis, which, we thought, could have caused abscess or inflammatory granuloma.

Aged↗
PubMed1991

Extensor tendon rupture after osteoarthrosis of the wrist associated with nonrheumatoid positive ulnar variance.

Rupture of the extensor tendon after osteoarthrosis of the wrist associated with nonrheumatoid, positive ulnar variance is uncommon. Eight cases were seen in the last five years. They included five men and three women, whose ages ranged from 54 to 82 years (average, 70 years). In all the cases, roentgenograms revealed osteoarthrotic changes in the wrist and dorsal subluxation or dislocation of the ulnar heads. Seven cases had operations. Friction with the dorsally subluxated or dislocated ulnar head and the osteophytes surrounding it caused these tendons to rupture. It was impossible to use end-to-end sutures, so tendon transfers or tendon grafts were performed. The patients were evaluated one to four years after surgery. Three patients complained of some disability in their daily lives, notably, limited flexion of their fingers. It is important that during surgery the reconstructed tendons should not be strained excessively.

Aged↗
PubMed1990

A nuclear protein derived from brain cells stimulates transcription of the human neurotropic virus promoter, JCVE, in vitro.

The 98-base pair enhancer/promoter sequence is critical for cell type-specific transcription of the human neurotropic viral promoter, JCVE, in glial cells. Transcriptionally active extracts were prepared from glial cells and used to identify cis- and trans-acting regulatory elements that are involved in the glial-specific activation of the JCVE promoter. Results indicate that multiple regulatory sequences within the 98-base pair repeat specifically bind to nuclear proteins present in glial cells and positively regulate viral early RNA synthesis. The central region of the repeat, designated domain-B, interacts with a 45-kDa nuclear protein present in brain cells. This brain-specific protein was purified by conventional and DNA affinity chromatography. Complementation of the highly purified protein with HeLa extract significantly increased JCVE promoter activity. Thus, association of the novel glial-origin transcription factor with its target sequence increases transcription of the JCVE promoter in a non-glial context.

Animals↗
PubMed1990

Trans-activation of the JC virus late promoter by the tat protein of type 1 human immunodeficiency virus in glial cells.

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system caused by the JC virus (JCV), a human papovavirus. PML is a relatively rare disease seen predominantly in immunocompromised individuals and is a frequent complication observed in AIDS patients. The significantly higher incidence of PML in AIDS patients than in other immunosuppressive disorders has suggested that the presence of human immunodeficiency virus type 1 (HIV-1) in the brain may directly or indirectly contribute to the pathogenesis of this disease. In the present study we have examined the expression of the JCV genome in both glial and non-glial cells in the presence of HIV-1 regulatory proteins. We find that the HIV-1-encoded trans-regulatory protein tat increases the basal activity of the JCV late promoter, JCVL, in glial cells. In a reciprocal experiment, the JCV early protein, the large tumor antigen, stimulates expression from JCVL and HIV-1 long terminal repeat promoter in both glial and non-glial cells. This trans-activation occurs at the level of RNA synthesis, as measured by the rate of transcription, stability of the message, and translation. We conclude that the presence of the HIV-1-encoded tat protein may positively affect the JCV lytic cycle in glial cells by stimulating JCV gene expression. Our results suggest a mechanism for the relatively high incidence of PML in AIDS patients than in other immunosuppressive disorders. Furthermore, our findings indicate that the HIV-1 regulatory protein tat may stimulate other viral and perhaps cellular promoters, in addition to its own.

Cell Line↗
PubMed1990

Effects of pretreatment with 2-O-octadecylascorbic acid, a novel free radical scavenger, on reperfusion-induced arrhythmias in isolated perfused rat hearts.

The effects of pretreatment with 2-O-octadecylascorbic acid (CV-3611), a novel liposoluble free radical scavenger, on reperfusion-induced arrhythmias were studied in isolated perfused rat hearts (n = 15 per group). The hearts were subjected to 10 min of coronary artery occlusion and 3 min of reperfusion. Pretreatment with CV-3611 (5 and 20 mg/kg) reduced the incidence of ventricular fibrillation (VF; reversible plus sustained) from its control value of 93% to 47% (p less than 0.05). Furthermore, CV-3611 reduced the incidence of sustained VF in a dose-dependent manner, from 67% in the control group to 13% in the CV-3611, 20 mg/kg treated group (p less than 0.01). CV-3611 (5 and 20 mg/kg) reduced the incidence of ventricular tachycardia (VT) from its control value of 93% to 73%. Pretreatment with ascorbic acid (5 mg/kg) had no effect on VF and VT. The myocardial content of CV-3611 was proportional to the dosage. We concluded that CV-3611 could reduce significantly the susceptibility to reperfusion-induced arrhythmias, especially VF, and that its effect may be due to the elimination of oxygen-derived free radicals by CV-3611 present in the membrane and the capture of lipid radicals, thereby inhibiting lipid peroxidation.

Animals↗
PubMed1990

The third nationwide survey in Japan of vitamin K deficiency in infancy.

The occurrence of hemorrhagic disease due to vitamin K (VK) deficiency beyond the neonatal period has come under investigation in Japan. In 1980 the 1st nationwide survey was conducted in Japan by Nakayama and others, and was followed by the 2nd nationwide survey in 1985 by Hanawa. The present survey was designed to further monitor the incidence of this disease in Japan during the 3-year period from July 1985 to June 1988. Questionnaires were sent to 1,315 hospitals having more than 200 beds, located throughout Japan. Responses were received from 775 hospitals, for an answer rate of 58.9%. The total number of reported cases was 175, including 129 idiopathic type, 28 secondary type and 18 near-miss type. In this survey it was revealed that the incidence rate of the idiopathic type of vitamin K deficiency in infancy (VKDI) has decreased remarkably, to about one-fourth that reported in the first survey. The declining incidence rate of VK deficiency in Japan is considered to be the result of ever more widespread prophylactic administration of VK during the neonatal period, as most occurrences of VK deficiency in infancy are preventable by prophylactic administration of VK from the neonatal period. However, in 16 cases of the idiopathic type of VK deficiency found in the present survey, VK had been administered at least once during or after the neonatal period. This shows the heterogeneity of this condition.

Female↗
PubMed1990

Relationship between proliferation and cell cycle-dependent Ca2+ influx induced by a combination of thyrotropin and insulin-like growth factor-I in rat thyroid cells.

The mechanism of cell proliferation by a combination of thyroid-stimulating hormone (TSH) and insulin-like growth factor-I (IGF-I) was studied in rat thyroid (FRTL-5) cells. IGF-I stimulated an approximately 3.5-fold increase in the rate of Ca2+ influx sustained for at least 6 h in TSH-pretreated cells but not in quiescent cells. The significant cell proliferation was observed when TSH-primed cells were incubated with IGF-I for 24 h but not for 12 h. IGF-I stimulated the rate of Ca2+ influx in a dose-dependent manner that was similar to that for induction of DNA synthesis. Both Ca2+ influx and DNA synthesis observed in response to IGF-I in TSH-primed cells were inhibited by cobalt. In addition, the stimulations of Ca2+ influx and DNA synthesis by IGF-I were dependent on extracellular Ca2+ in TSH-pretreated cells. When TSH-primed cells were pretreated with pertussis toxin, both IGF-I-induced Ca2+ influx and DNA synthesis were abolished. However, pertussis toxin did not block the priming action of TSH or forskolin. When calcium entry was induced by Bay K8644, it stimulated cell growth in TSH-primed cells but not in quiescent cells. Moreover, cobalt and lanthanum inhibited DNA synthesis even when added several hours after the addition of Bay K8644 but not when added 24 h after the growth factor in TSH-primed cells. These findings suggest that at least two important mechanisms may work in response to IGF-I only in the TSH-primed G1 phase of the cell cycle: first, IGF-I can activate directly or indirectly the Ca2+ channel via a pertussis toxin-sensitive substrate in TSH-primed cells; and second, a long lasting calcium entry by IGF-I may be a cell cycle-dependent mitogenic signal.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1990

Metabolic risk factors in the normolipidemic male patients with angiographically defined coronary artery disease.

The relationship of plasma lipid and apolipoprotein (apo) concentrations and plasma insulin response to oral glucose load to angiographically determined coronary artery disease (CAD) was investigated in 65 normolipidemic (plasma cholesterol less than 230 mg/dl and plasma triglyceride less than 150 mg/dl) males. According to the results of coronary angiography, the patients were divided into 2 groups: patients with normal coronary artery, NCA group (n = 21); and patients with coronary artery disease, CAD group (n = 44). No significant differences in concentrations of plasma cholesterol and triglyceride were observed between the CAD and NCA groups. In the CAD group cumulative lifetime tobacco consumption was higher and high density lipoprotein (HDL) cholesterol concentration was lower than those in the NCA group. The variables that correlated with the severity of CAD, defined by the number of lesions and percent stenosis, were levels of plasma apo A-I and apo B. Prevalence of subjects with reduced oral glucose tolerance did not differ between 2 groups. However, hyperinsulinemic response to oral glucose load was present in the CAD group. HDL-cholesterol concentration, the sum of plasma insulin levels and the magnitude of the early insulin response during oral glucose challenge were accurate predictors of the presence of but not the severity of CAD. Multivariate analysis of the data confirmed the independent effect of plasma levels of apo A-I and apo B on the severity of CAD. The present data indicated that plasma levels of apo A-I and apo B were powerful discriminators in the normolipidemic CAD patients and that a high insulin response might be an indicator of enhanced susceptibility to the distinct coronary atherosclerosis.

Adult↗
PubMed1990

Neurosyphilis manifesting as a focal mass lesion: computed tomographic and magnetic resonance imaging features--case report.

The computed tomographic (CT) and magnetic resonance (MR) imaging findings in a middle-aged male with cerebral syphilis are described. He presented with convulsive seizures and focal neurological deficits. A CT scan revealed a slightly enhanced, low-density mass in the left parieto-occipital region. MR imaging showed low intensity on T1-weighted images and high intensity on T2-weighted images. He was initially diagnosed as having a low-grade glioma. However, intraoperative histological examination of a small surgical specimen revealed no tumor cells but heavy infiltration of inflammatory cells in the meninges and cerebral parenchyma. Immunostaining for Treponema organisms by the peroxidase-antiperoxidase method was positive. Although the clinical and radiological findings are nonspecific, neurosyphilis should be considered in any patient in whom a nonspecific mass lesion is demonstrated by CT and MR imaging.

Humans↗
PubMed1990

Changes of eye-blink activities during hypnotic state.

Three experiments were conducted to examine eye-blink activity during the hypnotic state. The results were as follows: (1) eye-blink rate was dramatically reduced during the hypnotic as compared to the nonhypnotic state, (2) blink-rate variability between events (for example, the task and rest period) was smaller under the hypnotic than under the nonhypnotic state, (3) decrements, after induction of hypnosis, were observed in all aspects of blink-wave attributes (amplitude, duration, slope, and area). These findings can be interpreted in terms of the facilitation of motor inhibition by hypnosis.

Adult↗
PubMed1990

Purification and characterization of virginiae butanolide C-binding protein, a possible pleiotropic signal-transducer in Streptomyces virginiae.

Virginiae butanolide C (VB-C) is an autoregulator which triggers virginiamycin production in Streptomyces virginiae. A new binding assay with tritium-labeled VB-C analogue (2,3-cis-2-(1'-hydroxy-[6',7'-3H]heptyl)-3-(hydroxymethyl)butanolide+ ++ ) was developed and a specific VB-C binding protein was purified to homogeneity from crude extracts of S. virginiae by ammonium sulfate fractionation, DEAE-Sephacel and Sephadex G-100 column chromatographies, hydrophobic HPLC on phenyl 5PW and native polyacrylamide gel electrophoresis. The VB-C binding protein showed an apparent Mr of 35,800 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Mr of 26,000 approximately 44,000 on native molecular sieve HPLC, indicating the monomeric nature of the binding protein. The binding protein efficiently bound to a VB affinity column and eluted specifically by VB-C, which confirmed the specific nature of the binding protein. The binding activity decreased by 40% in the presence of genomic DNA from S. virginiae, indicating interaction between the VB-C binding protein and the DNA.

4-Butyrolactone↗
PubMed1990

[The expression of ras p21 product in hepatocellular carcinoma].

To elucidate the cell biological significance of ras oncogene, the expression of ras-p21 was analyzed in 53 cases of liver tissues including 34 cases of hepatocellular carcinoma (HCC), by using immunohistochemical method. In result, 22 (65%) cases of 34 HCC and 34 (79%) cases of 43 liver cirrhosis were positive for p21, whereas all of chronic hepatitis and normal livers were negative. Especially, comparative study between the expression of p21 and clinicopathological background of HCC revealed that p21 was prominently expressed in well differentiated form, nodular type, small liver cancer, and the cases showing AFP levels below 400 ng/ml. From these results, it was indicated that ras oncogene might play an important role in malignant transformation of hepatocytes or differentiation of HCC.

Carcinoma, Hepatocellular↗
PubMed1990

[Noncontact and noninvasive microwave biological measurements].

Without contact probes, the signals of small human body surface movements were obtained with microwave Doppler sensors using a two-phase interferometric method. The signals were then compared with mechanocardiographic records routinely obtained by contact transducers. Furthermore, this system was applied to patients wearing clothes. The study subjects consisted of 20 cardiac patients and 10 normal controls. 1. The microwave signals obtained in the cervical and precordial regions were similar to those of the mechanocardiographic recordings, such as the carotid pulse and jugular venous pulse tracings and the apexcardiogram. There was a significant correlation between left ventricular ejection time (LVET) obtained by microwave Doppler sensors and that by the carotid pulse tracing (r = 0.95). 2. The signals of the microwave Doppler sensor were obtained from the patients wearing clothes. The heart beat components were distinguished from respiratory motion and patients' movements using band-pass filters. These results suggest that this method is capable of evaluating cardiac function noninvasively and thus has a distinct advantage in the field of non-contact measurements.

Heart Function Tests↗