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Biomedical subjects

N Aoyama

Publications and source records attributed to N Aoyama.

14 recordsLinked to original sources
PubMed1992

Overlap of the p53-responsive element and cAMP-responsive element in the enhancer of human T-cell leukemia virus type I.

The wild-type p53 protein suppresses transformation, but certain missense mutants of p53 can transform cells. Although the wild-type p53 protein contains a transcriptional activation domain, no p53-responsive element has been identified. Here, we identified the p53-responsive element within the Tax-responsive element [21-base-pair (bp) enhancer] of human T-cell leukemia virus type I. Mutation analysis of the 21-bp enhancer indicated that the 16-bp sequence containing the cAMP-responsive element and its surrounding sequence was responsible for p53-induced transactivation. This 16-bp sequence was demonstrated to bind specifically to wild-type human p53 protein in vitro. Using a series of deletion mutants of p53, we showed that almost the entire region of p53 is needed for the transactivating capacity. Furthermore, the transforming mutants of p53 were unable to act as transcriptional activators. The p53-responsive element identified here should be useful to analyze the mechanism by which p53 regulates expression of a set of genes with a negative effect on cellular growth.

Animals↗
PubMed1992

Effects of hormonal supplements on the maintenance of cardiac function in potential donor patients after cerebral death.

It is well-known that cardiac function in cerebrally dead patients rapidly deteriorates, leaving the organ unfit for donation. This study investigated whether or not cardiac function in patients with cerebral death can be maintained in a desirable condition with hormonal supplementation. In studies of changes in hormones before and after cerebral death, insulin, glucagon, triiodothyronine, thyroxine, cortisol, vasopressin, epinephrine, and norepinephrine values were measured with a lapse of time after cerebral death. Among them, triiodothyronine and cortisol levels were markedly reduced after cerebral death; therefore, these two hormones were selected as hormonal supplements. The average period from the judgment of cerebral death to cardiac arrest was 4.3 days in 12 patients with no hormonal supplement (group I) and more than 11.5 days in 4 patients with hormonal supplement (group II). This period for patients in group II was significantly longer (p less than 0.05). In 2 of the group II patients the hormonal supplementation was discontinued at the family's request, and in the other 2 patients, it was discontinued because of proposed renal donation. Hemodynamic comparisons between the two groups showed that the mean arterial pressure and the left ventricular maximum dp/dt were significantly higher (p less than 0.01) as was the cardiac index (p less than 0.05) on the 3rd day after cerebral death in members of group II. Thereafter, in group II, an excellent hemodynamic state was maintained until hormonal supplements were discontinued. We conclude that the triiodothyronine and cortisol supplements were effective in the maintenance of cardiac function in patients after cerebral death.

Adolescent↗
PubMed1992

[A case of urinary bladder hernia].

A 77-year-old male visited our hospital complaining of swelling in the right scrotal and inguinal region, urinary urgency and difficulty of urination. Physical examination revealed an elastic soft mass in the right inguinal region toward the right scrotum. Rectal examination proved that the prostate was moderately enlarged. Cystogram and urethrography showed hernia of the bladder into the right scrotum and benign prostatic hyperplasia. Urodynamic studies demonstrated organic obstruction in the lower urinary tract. Transurethral resection of the prostate was done for benign prostatic hyperplasia. Later, surgical treatment for the bladder hernia was performed by replacing the bladder into the pelvic cavity and closing the hernial ring without resection of the bladder wall. The bladder hernia proved to be a para-peritoneal type. The postoperative course was uneventful. The previous reports of urinary bladder hernia are reviewed and the incidence, etiology, diagnosis the treatment are discussed.

Aged↗
PubMed1992

[Intentional hypotension therapy induced by nitroglycerin and the changes in the intracranial pressure for acute hemorrhagic intracranial lesions].

It is reported that nitroglycerin (NTG) induces the elevation of intracranial pressure (ICP). Because of it, the use of NTG in patients exhibiting the increased ICP especially in the neurosurgical field is thought to be avoided. However, these reported cases dealt with normal patients. Few cases under the condition of exactly increased intracranial pressure were studied. Our 31 patients of the hemorrhagic intracranial lesion (subarachnoid hemorrhage and hypertensive intracranial hemorrhage) at the acute stage were treated by NTG infusion as an antihypertensive drug, and the ICP was measured using the epidural pressure transducer. The 31 patients were divided into three groups. Group 1 consists of the 14 patients exhibiting normal ICP (< 15mmHg). Group 2 consists of 9 patients showing elevated ICP (15mmHg < or =). Group 3 consists of 8 patients treated with glycerol before the NTG infusion. Group 1 demonstrates a statistically significant elevation of ICP corresponding with the blood pressure depression. Group 2 showed no significant elevation of it. Group 3 disclosed no remarkable elevation of it both in the elevated ICP cases and the normal ICP cases. As mentioned above, the intravenous NTG caused a remarkable increase of ICP in the normal compliance of the intracranial contents and no elevation of ICP in the poor compliance. We conclude that NTG can be used for blood pressure control at an acute stage even in hemorrhagic intracranial lesion as anti-depressor.

Acute Disease↗
PubMed1992

[Through-bougie esophageal prosthesis intubation--a method and its evaluation].

A new method was developed for nonsurgical peroral positioning of an esophageal prosthesis by using bougie under X-ray control in 1983. I referred to it as "through-bougie esophageal prosthesis intubation". The external diameter of a bougie is equal to the internal diameter of an esophageal prosthesis, so intubation can be performed safely and smoothly. This method was carried out in 44 cases (40 cases of cancerous stenosis, and 4 cases of cicatrical stenosis), and insertion of an esophageal prosthesis was possible in all cases. The improvement rate of peroral feeding was 88.6%. This new method is useful for the patients, who have dysphasia due to inoperable stenosis of the upper gastrointestinal tract.

Aged↗
PubMed1991

Transcellular transport of organic anions in the isolated perfused rat liver: the differential effects of monensin and colchicine.

Nonbile salt cholephiles and bile salts are two classes of organic anions that are efficiently taken up and excreted by the liver. Recent evidence suggests that a microtubular system-dependent, colchicine-sensitive transcellular pathway may transport both classes of these ligands. The relationship of this pathway to flux rates, however, remains unclear. Some structural evidence suggests an important role for a Golgi-associated vesicular system. Monensin, like colchicine, is a perturbing agent that is believed to target primarily Golgi and related organelles. The effects of a minimal effective dose of both colchicine (0.06 mg to 0.12 mg/100 gm body wt) and monensin (0.6 mg/100 gm body wt) were examined in the isolated perfused rat liver in a single-pass mode. The nonbile salt cholephile, phenol red, was studied at two doses: 1 nmol and 5 mumol. Sodium taurocholate was studied at three doses: 2 nmol, 1 mumol and 5 mumol. Colchicine affected the transcellular transport for both classes of organic anions equally. Partially inhibitory effects on both anions occurred only at high ligand flux rates. In contrast, monensin greatly impaired the transport of nonbile salt cholephiles but had no influence on transcellular bile salt flux. We conclude that the monensin effect appears to define a distinct transcellular transport pathway for each of the two classes of organic anions.

Animals↗
PubMed1991

A novel transcellular transport pathway for non-bile salt cholephilic organic anions.

Non-bile salt cholephilic organic anions comprise a single class of nonhomologous ligands having a range of hydrophobicity. Hydrophobicity enhances the hepatic extraction of cholephiles as well as their partitioning into secreted biliary lipid particles. When hydrophobicity is correlated with patterns of biliary excretion for studying transcellular transport, however, the more hydrophobic probes are unsuitable. Specifically, with the isolated perfused rat liver technique, the excretory times for sulfobromophthalein and rose bengal were significantly longer compared with that for the much more hydrophilic analogue phenol red (PR), which showed only a single, nearly symmetrical excretory peak at 10 min. Colchicine affected the apparently well-defined PR pathway only at a saturation dose (10,000 times the tracer dose). In contrast, the effect of a different perturbant, monensin, was striking at a tracer dose of PR, but was less evident at a saturation dose. The combined administration of colchicine and monensin had no additive inhibitory effect on PR excretion at tracer doses. At a saturation dose of PR, where monensin is less inhibiting, however, a significant additive inhibitory effect was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[Enhanced effect of intraperitoneal administration of CDDP combined with caffeine against peritoneal metastasis].

The enhanced effect of CDDP combined with caffeine against P-388 leukemia was investigated. No synergistic effect was shown after one hour simultaneous treatment with CDDP and caffeine. But the growth inhibition was enhanced by the addition of caffeine after one hour treatment with CDDP. It is suggested that caffeine inhibits DNA repair by the reduction of CDDP-induced elongation of G2 + M phase. The increase in life span of mice after ip transplantation was observed by frequent ip injections of caffeine after CDDP injection. It is suggested that the effect of intraperitoneal administration of CDDP against peritoneal metastasis is enhanced by combination with caffeine.

Animals↗
PubMed1991

Hepatic extraction of organic anions in the rat depends on ligand hydrophobicity.

Non-bile-salt cholephilic organic anions are efficiently taken up by the liver. Recent work from our group has suggested the possible importance of relative hydrophobicity among various organic anions in hepatic uptake. To further validate and clarify this, we studied hepatic extraction of five different cholephilic dyes using the isolated perfused rat liver in single-pass mode. Albumin binding affinities and capacities for each of the ligands were measured in vitro to permit evaluation of in vivo interactions for each of them over a spectrum of unbound ligand concentrations. As expected, a strong positive correlation was found between ligand hydrophobicity and the relative degree of albumin binding affinity and capacity. Using appropriate experimental conditions, we also found a strong positive correlation between hepatic extraction efficiency for a given ligand and both its hydrophobicity and its unbound concentration. These data indicate that where the unbound ligand concentration is significant, the greater the ligand hydrophobicity, the greater is its efficiency of hepatic extraction. We conclude that hepatic extraction efficiency for non-bile-salt cholephilic organic anions depends on a combination of ligand hydrophilic/hydrophobic balance and the availability of the unbound ligand for uptake.

Animals↗
PubMed1990

[Automatic polishing of dental prostheses. 1. Development of a centrifugal barrel finishing apparatus].

A centrifugal barrel finishing apparatus with a variable turn table rotational speed (250-1,000 rpm) was newly developed and barrel finishing of Ni-Cr casting plates (10 x 10 x 2 mm) was performed using alumina base chips. When using the sample with a mirror face the amount of polishing and the surface roughness increased and the surface gloss decreased with the increase in rotation speed. A high rotational speed was useful for coarse polishing and low rotational speed was useful for fine polishing. The continuous barrel polishing was trially performed using the sample prepared by the carborundum wheel under variable rotational speed. Automatic polishing to fine polishing could be done using this apparatus.

Dental Polishing↗