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L H Wu

Publications and source records attributed to L H Wu.

At least 73 records · Page 4Linked to original sources
PubMed1986

Dynamic behavior of histone H1 microinjected into HeLa cells.

Histone H1 was purified from bovine thymus and radiolabeled with tritium by reductive methylation or with 125I using chloramine-T. Red blood cell-mediated microinjection was then used to introduce the labeled H1 molecules into HeLa cells synchronized in S phase. The injected H1 molecules rapidly entered HeLa nuclei, and a number of tests indicate that their association with chromatin was equivalent to that endogenous histone H1. The injected molecules copurified with HeLa cell nucleosomes, exhibited a half-life of approximately 100 h, and were hyperphosphorylated at mitosis. When injected HeLa cells were fused with mouse 3T3 fibroblasts less than 10% of the labeled H1 molecules migrated to mouse nuclei during the next 48 h. Thus, the intracellular behavior of histone H1 differs markedly from that of high mobility group proteins 1 and 2 (HMG1 and HMG2), which rapidly equilibrate between human and mouse nuclei after heterokaryon formation (Rechsteiner, M., and L. Kuehl, 1979, Cell, 16:901-908; Wu, L., M. Rechsteiner, and L. Kuehl, 1981, J. Cell Biol, 91: 488-496). Despite their slow rate of migration between nuclei, the injected H1 molecules were evenly distributed on mouse and human genomes soon after mitosis of HeLa-3T3 heterokaryons. These results suggest that although most histone H1 molecules are stably associated with interphase chromatin, they undergo extensive redistribution after mitosis.

Animals↗
PubMed1986

Stability of NADPH: effect of various factors on the kinetics of degradation.

Seeking to minimize degradation of NADPH during storage, reagent preparation, and assays, we investigated the effects of pH, temperature, and ionic strength as well as the effects of phosphate and acetate. NADH was also included for comparison. Our results indicate that the rate of degradation of NADPH is proportional most importantly to temperature and concentrations of hydronium ion, but also to concentrations of phosphate and acetate. The degradation rate decreased with increasing ionic strength at neutral pH, but increased slightly at lower pH. NADPH generally is less stable than NADH under the same conditions. The reaction orders with respect to hydronium ion and anions were near 1 for NADH degradation reactions, about 0.5 for NADPH. Rate constants for NADH and NADPH differed more at higher pH and lower phosphate and acetate concentrations.

Acetates↗
PubMed1985

RBC-mediated microinjection of chromatin components into cultured mammalian cells.

Radiolabeled DNA fragments or nuclear proteins were encapsulated within human erythrocytes, and the erythrocytes were then fused with cultured mammalian cells using Sendai virus. Autoradiography revealed that 125I-labeled DNA fragments remained dispersed in the cytoplasm and disappeared with a half-life of 24 hours. In contrast, the nuclear proteins, HMG1, HMG2, HMG17 and histone H1, rapidly localized within HeLa nuclei and exhibited half lives greater than 80 hours. Several biochemical criteria indicate that the association of the injected nuclear proteins with chromatin faithfully mimics the behavior of their endogenous counterparts.

Animals↗
PubMed1984

Studies on adenosine triphosphate transphosphorylases. Amino acid sequence of rabbit muscle ATP-AMP transphosphorylase.

The total amino acid sequence of rabbit muscle adenylate kinase has been determined, and the single polypeptide chain of 194 amino acid residues starts with N-acetylmethionine and ends with leucyllysine at its carboxyl terminus, in agreement with the earlier data on its amino acid composition [Mahowald, T. A., Noltmann, E. A., & Kuby, S. A. (1962) J. Biol. Chem. 237, 1138-1145] and its carboxyl-terminus sequence [Olson, O. E., & Kuby, S. A. (1964) J. Biol. Chem. 239, 460-467]. Elucidation of the primary structure was based on tryptic and chymotryptic cleavages of the performic acid oxidized protein, cyanogen bromide cleavages of the 14C-labeled S-carboxymethylated protein at its five methionine sites (followed by maleylation of peptide fragments), and tryptic cleavages at its 12 arginine sites of the maleylated 14C-labeled S-carboxymethylated protein. Calf muscle myokinase, whose sequence has also been established, differs primarily from the rabbit muscle myokinase's sequence in the following: His-30 is replaced by Gln-30; Lys-56 is replaced by Met-56; Ala-84 and Asp 85 are replaced by Val-84 and Asn-85. A comparison of the four muscle-type adenylate kinases, whose covalent structures have now been determined, viz., rabbit, calf, porcine, and human [for the latter two sequences see Heil, A., Müller, G., Noda, L., Pinder, T., Schirmer, H., Schirmer, I., & Von Zabern, I. (1974) Eur. J. Biochem. 43, 131-144, and Von Zabern, I., Wittmann-Liebold, B., Untucht-Grau, R., Schirmer, R. H., & Pai, E. F. (1976) Eur. J. Biochem. 68, 281-290], demonstrates an extraordinary degree of homology.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylate Kinase↗
PubMed1984

Clinical and pathological characteristics of carcinosarcoma of the esophagus: report of four cases.

Carcinosarcoma of the esophagus is a rare malignant neoplasm composed of both carcinomatous and sarcomatous elements. Four out of 850 patients with carcinoma of the esophagus or the cardiac portion of the stomach undergoing operation at Capital Hospital, Beijing, had carcinosarcoma of the esophagus. They ranged from 50 to 58 years old, but only 45% of all 850 patients with carcinoma were in the age group from 51 through 60 years old. All 4 patients with carcinosarcoma of the esophagus were men. On barium swallow esophagogram, the 4 patients had a characteristic intraluminal polypoid lesion in the middle third of the esophagus. Such lesions of the esophagus also can occur in patients with benign fibrovascular polyps, leiomyoma, and the polypoid form of esophageal carcinoma and esophageal melanoma. The last two can be differentiated from carcinosarcoma only by pathological examination after excision. After radical excision and esophagogastrostomy, the 4 patients were followed up for 19, 4, 4, and 3 years. They were in good condition without recurrence.

Carcinosarcoma↗
PubMed1983

Surgical treatment of carcinoma of the esophagus and cardiac portion of the stomach in 850 patients.

From 1961 to 1978, 850 patients with carcinoma of the esophagus or cardiac portion of the stomach were operated on in the Capital Hospital of the Chinese Academy of Medical Sciences. Eighty-three percent of the patients were men, and about 45% of the patients ranged from 51 through 60 years old. Just over half of the patients were seen when the lesion was at a late stage of development. The thirty-day postoperative mortality among 664 patients with a restricted lesion was 10%. Leakage of the esophagogastric anastomosis was the chief cause of morbidity, and about half of the patients with this condition died. The 5-year survival among these 664 patients with a restricted lesion was 22%. Retrospective review of the literature confirmed the possibility of further increasing resectability, further decreasing mortality, and providing greater long-term survival if early complete resection of the tumor can be carried out.

Adenocarcinoma↗
PubMed1983

Tracheobronchial tumors: an eighteen-year series from Capital Hospital, Peking, China.

From 1961 to 1979 in Capital Hospital, Peking, China, 27 patients with tracheobronchial tumors were treated: 20 underwent operation and 7 were managed by palliative measures. All 27 patients had an intraluminal lesion of the trachea or major bronchi. Respiratory obstruction was the main clinical manifestation of the tracheal tumors. Chronic suppurative infection of the lung was the principal clinical manifestation of the bronchial tumors. Histological diagnosis of these 27 patients revealed ten different cell types: squamous cell carcinoma (10 patients, including the 7 who did not undergo operation); adenoid cystic carcinoma (5 patients); carcinoid, hamartoma, neurofibroma, and papilloma (2 patients each, respectively); and leiomyoma, hemangioma, chondroma, and teratoma (1 each, respectively). The operative methods used in 20 patients were lateral resection of tracheal wall (2 patients), resection of left main bronchial root (1), local excision (5), lobectomy (5), pneumonectomy (3), bronchoscopy (1), and exploratory operation and tracheostomy (3). Local excision or lateral wall resection of the trachea was chosen for benign or less dangerously malignant tracheal tumors. Lobectomy or pneumonectomy was performed for the secondarily infected, destroyed lungs in patients with bronchial tumors.

Adolescent↗