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N Han

Publications and source records attributed to N Han.

26 records · Page 2Linked to original sources
PubMed1991

[Determination of DNA base composition and levels of DNA-DNA hybridization of Actinobacillus actinomycetemcomitans].

Using the strains of Actinobacillus actinomycetemcomitans (Aa) and Haemophilus aphrophilus (Haph) in experiments, the mole percent quanine plus cytosine content (mol% G + C) and level of DNA-DNA hybridization (DNA homology) were determined for the first time in oral microbiologic study in China. DNA was extracted by Marmur's method. The mol% G + C of DNA was determined by thermal denaturation method (Tm). DNA-DNA hybridization was carried out by De Ley's optical procedure (initial renaturation rate). The results are as follows: 1. The mol% G + C of DNA of Aa is different from that of Haph. 2. 2 strains of Aa had high DNA homology (73.8%) and the DNA homology between Aa and Haph was low (33.9%). It was confirmed that Aa and Haph are different species. In order to identify the bacteria in periodontal pockets accurately, it is necessary to carry out the nucleic acid study in bacterial classification.

Actinobacillus↗
PubMed1990

[Hepatocellular carcinoma with extrahepatic malignancies].

A clinical investigation of 16 hepatocellular carcinoma (HCC) patients with extrahepatic malignancies (13 male, 3 female) has been conducted. The age of these patients ranged from 55 to 76 years. Three of these double cancer cases were hemocronous, and 13 were heterochronous. The duration between the occurrence of the cancers ranged from 2 years and 4 months to 22 years. As for the site of the other cancer, the stomach was the most common organ (12 cases). In nine cases out of 16, the HCC was resected, whereas the other cases were treated with a TAE and hepatic artery ligation because the cancer were far advanced stages. Early detection of an HCC by AFP or an ultrasonographic examination, and a subsequent surgical resection in cases of a postoperative cancer patient with a liver dysfunction may lead to a more favorable prognosis.

Aged↗
PubMed1990

[Tissue UFT distribution and histological changes following UFT administration in metastatic liver cancer cases].

For the purpose of assessing the anti-tumor effect of UFT in metastatic liver cancer, blood futraful (FT), 5-fluorouracil (5-FU) and uracil levels and their distribution in tissue (cancer lesion, etc.) following oral UFT administration were examined in 10 surgically treated cases of metastatic liver cancer secondary to cancer of the large intestine and 4 cases of metastatic liver cancer secondary to stomach cancer. Liver tissue 5-FU distribution following UFT treatment was excellent. 5-FU concentration in liver cancer lesion was 0.164 +/- 0.128 micrograms/g, which was markedly higher than the minimal effective tissue concentration for 5-FU (0.050 micrograms/g). 5-FU level in normal tissue of the organ with primary cancer was significantly lower than that in the tumor-affected tissue of the same organ, while no difference in 5-FU level was noted between cancer-affected and normal tissues of the liver. Tissue 5-FU level in both primary and metastatic cancer lesions was significantly higher than the simultaneously determined blood 5-FU level. Histological findings of cancer-affected liver did not differ between different UFT dose levels, but degeneration of cancer cells was severe in some cases given high doses of UFT.

Aged↗
PubMed1988

[Cholangiocarcinoma associated with Caroli's disease].

We report on an autopsy case of cholangiocarcinoma associated with Caroli's disease. A 38-year-old woman was admitted to our hospital suffering from epigastralgia. A diagnosis of Caroli's disease was made after CT, US, and ERCP testing. Because of diffuse intrahepatic bile duct dilatation, the patient was treated with antibioticus. In August 1985, her CA 19-9 level was 3,800 U/ml. This data suggested the development of a carcinoma secondary to Caroli's disease, but no tumor in the liver had been detected in the US and CT examinations. The patient died on February 1, 1986, of hepatorenal failure, approximately seven years after her first admission. An autopsy revealed diffuse dilatation of the intrahepatic bile duct (Caroli's disease) with a cholangiocarcinoma.

Adenoma, Bile Duct↗
PubMed1988

[A case report of primary liver cancer with cerebral metastasis after hepatic resection].

A 67-year-old male, who had a left hepatectomy for hepatocellular carcinoma, was readmitted to our hospital because of a left hemiparesis. A brain computed tomography scan and an r-carotid angiogram revealed a large mass involving the right parietal area, and thus a brain tumor removal was performed. A histological diagnosis of the removed brain tumor found it to be a metastatic, hepatocellular carcinoma. The patient died of pulmonary congestion due to lung metastasis, approximately 2 years and seven months after hepatectomy, and 1 year and three months after the removal of this metastatic brain tumor. In selected cases, the removal of a metastatic brain tumor seems to bring about improvements in the quality and duration of life.

Aged↗
PubMed1981

Mechanism of resistance of variants of the Lewis lung carcinoma to N-(phosphonacetyl)-L-aspartic acid.

Variants of the Lewis lung carcinoma were selected for resistance to N-(phosphonacetyl)-L-aspartic acid (PALA) by treatment of tumor-bearing mice with repetitive subcurative doses of PALA. The specific activity of the target enzyme, L-aspartic acid transcarbamylase (ATCase), was measured in the four variants developed. Three had markedly elevated ATCase activities; however, the fourth line, LL/PALA-C, had an ATCase activity identical to that of the parent, PALA-sensitive line (LL/O). One high-ATCase variant, LL/PALA-J, and LL/PALA-C were compared with LL/O in subsequent biochemical studies on the mechanism of resistance to PALA. Enzyme activities in the salvage pathways which phosphorylate pyrimidine nucleosides and deoxynucleosides were found to be similar in all three lines. ATCase in these lines exhibits closely comparable kinetics with its natural substrates as well as with PALA. The time courses of restitution of ATCase after a single therapeutic dose of PALA show that both resistant variants recover full activity more rapidly than the parent. Additionally, inhibition of ATCase 24 hr following graded doses of PALA is lower in the resistant lines. The uptake of [14C]PALA in vitro into cell lines derived from the three Lewis lung carcinomas apparently occurs by passive diffusion and at comparable rates in both sensitive and resistant cells. Analysis of the nucleotide content of tumors reveals comparable spectrums of purine and pyrimidine nucleotide levels in the LL/O and LL/PALA-C lines, whereas the LL/PALA-J line has augmented nucleotide pools. In all three lines, 24 hr after treatment with PALA (400 mg/kg), uridine and cytidine nucleotide levels were substantially diminished (70 to 80%) while adenosine 5'-triphosphate and guanosine 5'-triphosphate levels were elevated (50 to 100%). Estimations of precursor flux through the de novo pyrimidine pathway by measuring orotate and orotidine levels in tumors of mice treated with pyrazofurin (an inhibitor of orotidine-5'-monophosphate decarboxylase) and either 0.9% NaCl solution or PALA shows that PALA treatment eliminates orotate and orotidine accumulation in LL/O but reduces it by only 75 and 50% in LL/PALA-C and LL/PALA-J, respectively. Similarly, PALA treatment (20 microM) of tumor lines in culture provokes a dramatic decrease in the incorporation of NaH14CO3 into pyrimidine intermediates and nucleotides in the LL/O cell line only. Determinations of specific activities of the other enzymes in this pathway reveal that the activity of carbamyl phosphate synthetase II, the rate-limiting step, is elevated 2- to 3-fold in both resistant lines. Since carbamyl phosphate synthetase II exists as a complex with ATCase, the suggestion is made that levels of carbamyl phosphate synthetase II are collaterally important determinants of PALA activity. An augmented pool of carbamyl phosphate in the resistant variants may serve to competitively displace PALA from ATCase, diminish enzyme inhibition, and allow pyrimidine biosynthesis to proceed despite therapy.

Amides↗