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Biomedical subjects

T Higashi

Publications and source records attributed to T Higashi.

At least 289 records · Page 16Linked to original sources
PubMed1989

Hepatitis B virus markers in patients with schistosomiasis, liver cirrhosis and hepatocellular carcinoma in Khartoum, Sudan.

Markers of hepatitis A and B virus were tested in 88 adult Sudanese subjects in Khartoum, Sudan. The subjects consisted of 25 control hospitalized patients, 21 volunteer blood donors, 23 patients with hepatosplenic schistosomiasis, 13 patients with liver cirrhosis and 6 patients with hepatocellular carcinoma (HCC). Antibody to hepatitis A virus was detected in 96% of the total. Hepatitis B surface antigen (HBsAg) was positive in 4, 24, 22, 31, and 67% of the subject groups, respectively. Antibody against hepatitis B core antigen (HBcAb) of undiluted serum was positive in 60, 57, 65, 77 and 83%, and there was no difference in incidence among the groups. It was positive in 200X diluted serum in 4, 24, 17, 23 and 60%. HBsAg and HBcAb (200X) were detected more often in HCC patients than in the control subjects (p less than 0.01). Hepatitis B virus is an important factor in the etiology of HCC in the Sudan.

Adult↗
PubMed1989

The secretion of high molecular weight cathepsin B from cultured human liver cancers.

The biochemical characteristics of cathepsin B secreted from cultured human liver cancer cells were examined. The enzyme activity of culture medium against a synthetic substrate, N-carbobenzoxy-L-arginyl-L-arginine-4-methyl-coumaryl-7-amide, was dependent on the addition of cysteine, and the optimal pH was found to be 6.0. No activity was observed when the enzyme source was fresh medium not used for culture. These results suggest that the enzyme released from liver cancer cells is the thiol-protease cathepsin B. The molecular weight of the enzyme with 90% of the total activity was 40,000. Two cathepsin B molecules were found in liver tissue from patients with hepatocellular carcinoma (HCC); one was equivalent in size to the secreted enzyme, and a smaller one was the same as normal liver cathepsin B (27,000), which was also obtained from HCC-bearing cirrhotic liver. These results demonstrate that two molecules of cathepsin B are synthesized in liver cancer, and that the larger one is released into the surrounding tissue.

Cathepsin B↗
PubMed1989

Development of a new exposure monitoring system considering pulmonary ventilation (DEM 1).

Exposure evaluation is an essential facet in the assessment of the risks of exposure to toxic materials in the workplace. Presently, samples from the breathing atmosphere are measured in order to determine the level of individual exposure to toxic substances. This method, however, does not take into account the level of physical exertion during exposure. Physical activity is known to increase pulmonary ventilation by up to 10 times that of the level at rest. Thus, measurement of pulmonary ventilation, as well as the concentration of a toxic material in the air would provide valuable data in evaluating exposure. We have developed a device that measures and records the concentration of a toxic material in the air and pulmonary ventilation as predicted by heart rate both simultaneously and continuously. In this system, real time pulmonary ventilation is predicted from heart rate by using a regression equation that was obtained from the results of our study. The percentage error of predicted pulmonary ventilation at each heart rate is within 30%. The present study assessed the feasibility of the use of heart rate as the predictor of pulmonary ventilation. Our new exposure monitoring system is the first practical device that monitors the level of exposure dependent upon pulmonary ventilation and will be useful in the reevaluation of threshold limit values (TLV's) and in working management.

Adult↗
PubMed1989

Methylation at the CpG doublet in equine adenovirus genome.

Viral DNA obtained from the equine adenovirus propagated in equine transitional cell carcinoma (ETCC) cells and in equine fetal dermis cells were compared by cleaving with isoschizomeric restriction enzymes, HpaII and MspI, and then electrophoresed in 1.4 per cent agarose gels. Differences between the HpaII and MspI cleavage patterns were evident in viral DNA obtained only from the equine adenovirus propagated in ETCC cells, suggesting site specific methylation at CpG sequences.

Adenoviridae↗
PubMed1989

Nephrotoxicity of pyrroloquinoline quinone in rats.

When pyrroloquinoline quinone (PQQ) was intraperitoneally injected into rats daily for 4 days at a dose of 11.5 mg/kg body weight/injection, functional and morphologic changes of the kidneys were clearly observed. The most prominent finding was necrotic and degenerative changes of the proximal tubular epithelium as well as hematuria and an elevation of serum creatinine concentration.

Animals↗
PubMed1989

[Ga-67 scintigram in evaluation of malignant lymphoma of the thyroid originating from chronic thyroiditis].

At the Itoh Hospital, 27 patients with primary malignant lymphoma of the thyroid gland have been diagnosed from April 1985 to April 1988. Within the 27 patients, 8 patients were treated with a diagnosis of chronic thyroiditis during 1 year to 7 years at Itoh Hospital. Ga-67 scintigraphy was performed in the 8 patients as suspected malignant lymphoma. Of the 8 patients, 6 were very strong positive, 1 was strong positive and 1 was weak positive. All patients with Ga-67 strong positive scans should have a biopsy and the scans are helpful to direct the biopsy. Ga-67 scintigraphy is useful in the diagnosis of malignant lymphoma of the thyroid gland.

Aged↗
PubMed1988

Crystallization and preliminary crystallographic data of a truncated derivative from the human c-Ha-ras protein.

A truncated derivative of the human c-Ha-ras protein has been crystallized from polyethylene glycol 6000 solution by a vapour diffusion technique. The rectangular prism diffracts X-rays to at least 2.5 A resolution (1 A = 0.1 nm). The unit cell is monoclinic, space group P21, with unit cell parameters of a = 50.2 A, b = 110.9 A, c = 36.4 A, beta = 97.2 degrees. The unit cell contains four molecules.

Crystallization↗
PubMed1988

The relationship between Ga-67 accumulation and cell cycle in malignant tumor cells in vitro.

Previously we reported that the deposition of 67Ga into malignant tumor may be a sensitive index of proliferative activity in tumor cells. For the purpose of elucidation of this hypothesis, we investigated the relationship between the accumulation of 67Ga into malignant tumor cells and the cell cycle in vitro. We discovered that the uptake of both 67Ga and 59Fe into synchronized mouse tumor cells reaches a peak at the G2 stage which precedes cellular proliferation. Both iron and transferrin are specifically required by cells in culture for cell division, and the fact that 67Ga and 59Fe uptake into tumor cells peaks at the G2 stage of the cell cycle suggests that there is a correlation between 67Ga uptake and the rate of cellular proliferation in malignant tumor cells.

Animals↗
PubMed1988

Reevaluation of urinary excretion of coproporphyrins in lead-exposed workers.

Urinary concentrations of coproporphyrin I and III (CP I and III) were determined by high-performance liquid chromatography in 131 male workers exposed to lead, and the relationships between lead exposure and urinary coproporphyrins were reevaluated. CP I had a statistically significant correlation with lead in the blood (Pb-B), but it was not useful as an indicator of the effect of lead on heme metabolism. On the other hand, CP III had a good correlation with Pb-B and markedly increased when Pb-B levels exceeded 40 to 50 micrograms/100 ml. Both sensitivity and specificity were more than 80% when the health-based Pb-B limit and the screening level of CP III were fixed at 50 micrograms/100 ml and 50 micrograms/g creatinine, respectively. In conclusion, measurement of CP III is sufficiently sensitive and specific enough in practice for the early detection of health effects due to lead exposure in the same way as the measurement of delta-aminolevulinic acid in urine.

Adult↗
PubMed1988

Bone trabecular pattern analysis in Down's syndrome with the use of computed panoramic tomography with a laser scan system. Quantitative analysis with the power spectrum method.

A quantitative analysis of the mandibular bone trabeculae of 44 patients with Down's syndrome and 68 normal persons by means of panoramic tomography was performed with a laser scan system. The results showed that the normal persons exhibited a correlation between the trabecular pattern and aging, whereas the patients with Down's syndrome showed no such correlation. These findings were consistent with geromorphism, which is one of the systemic features of Down's syndrome.

Adult↗
PubMed1988

Salivary gland uptake of gallium-67 citrate after sialography.

Sialography may cause greatly increased Ga-67 activity within otherwise normal salivary glands. Five patients are presented in whom sialography with oily contrast material injected 8-26 days before Ga-67 imaging produced strongly positive examinations. In each patient it appears that sialography rather than pre-existing pathologic conditions accounted for the increased activity. Sialography-induced subclinical sialadenitis may be the mechanism for the phenomenon.

Adult↗
PubMed1988

Gallium-67 imaging in the evaluation of thyroid malignancy.

One hundred thirty-six patients with suspected thyroid malignancy were studied prospectively with Ga-67 imaging of the thyroid and whole body. All patients subsequently had diagnoses proven by biopsy or surgical resection. Patients with malignant tumors (anaplastic carcinoma, malignant lymphoma, adenocarcinoma, medullary carcinoma, adenocarcinoma with squamous cell transformation, and metastases to the thyroid from other tumors) were examined serially after appropriate therapy. The authors draw on their own experience and a literature review to propose the following indications for Ga-67 imaging in patients with thyroid disease: 1) suspected anaplastic carcinoma or malignant lymphoma of the thyroid gland, 2) detection of distant metastases of anaplastic thyroid carcinoma and malignant lymphoma, 3) evaluation of efficacy of therapy, 4) suspected metastases to the thyroid gland from other malignancies, and 5) differentiation of malignant lymphoma from chronic thyroiditis. The strengths, limitations, and potential pit-falls of the technique are discussed.

Adult↗
PubMed1988

A simple and useful method for simultaneous screening of elevated levels of expression of a variety of oncogenes in malignant cells.

Abnormal expression of various oncogenes has been implicated in the development of many malignant tumors. Although RNA blotting methods have been used to measure abnormal expression, they involve the time-consuming process of individually labeling the oncogene probes. To simplify this process we have attempted to develop a new method, termed simultaneous screening, which is based on the synthesis of radiolabeled cDNA corresponding to the mRNA population of malignant cells and on hybridization with various oncogene probes, immobilized on a membrane filter. This method circumvents the time-consuming process of the prevailing RNA blotting methods and is also sensitive enough to detect accurately a five- to ten-fold level of expression of rare mRNA (approximately 10 copies per cell). Overexpression of ten oncogenes was detected in a variety of malignant cells and mitogen-stimulated cells with this method. These results suggest that our simultaneous screening method can be used to examine the overexpression of oncogenes.

DNA↗
PubMed1988

Ultrasonographic characteristics of small hepatocellular carcinoma.

The ultrasonographic characteristics of hepatocellular carcinomas (HCC) were investigated. Four typical features of HCCs, "mosaic internal echo pattern", "halo", "lateral shadow" and "posterior echo enhancement", were not recognized in minute HCCs smaller than 2 cm in diameter. These characteristics developed as the tumors grew. Only hypoechoic space-occupying lesions can be considered as small HCCs. In differentiating small HCCs from hypoechoic non-malignant space-occupying lesions in the cirrhotic liver, the ratios of short to long dimensions of the lesions seemed to be important since the ratios of HCCs were significantly larger than those of non-malignant lesions. The fact that 3 hyperechoic small HCCs could not be diagnosed even by celiac arteriography has suggested to us that ultrasonically guided biopsies should be performed in order to differentiate from small hemangiomas. Serum alpha-fetoprotein (AFP) levels of 1/3 of the patients with HCCs were below 100 ng/ml, indicating that it is impossible to detect small HCCs only by measuring serum AFP.

Carcinoma, Hepatocellular↗