1301
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Lai HS, Chen WJ, Chen KM, Lee YN. Effects of monomeric and polymeric diets on small intestine following massive resection. TAIWAN YI XUE HUI ZA ZHI. JOURNAL OF THE FORMOSAN MEDICAL ASSOCIATION 1989; 88:982-8. [PMID: 2634733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Since the introduction of long-term total parental nutrition, it has been possible to raise the survival rate in patients with massive intestinal resection. How to increase the remaining intestinal mucosa hyperplasia in these patients has become the focus of many studies. Early postoperative enteral feeding with exogenous intraluminal nutrition was considered to be one of the most essential factors. The best enteral food pattern, however, is still not conclusive. In this study, we used the animal model of rats with 60% small intestinal resection, giving them different kinds of enteral diets through gastrostomy tubes. The monomeric diet included amino acid, glucose, disaccharide, and triglyceride. The polymeric diet included the usual source of nutrition such as protein, polysaccharide, and fat. The rats were killed three weeks later. Histopathological changes of the remaining bowel and H3 thymidine incorporation to mucosal DNa were measured. We found: (1) hyperplasia of the remaining bowel in the 60% resected rats was definitely increased more than the rats of the sham operation; (2) from the protein content, the DNA content of mucosa cells, the villus height and crypt depth points of view, the polymeric diet fed rats had a better adaptation; (3) on the 21st postoperative day, the DNA synthetic rate was still very high in polymeric diet fed rats, but returned to preoperative levels in rats fed with a monomeric diet. Our conclusion of this study is that a polymeric diet can contribute to a better intestinal mucosa regeneration than a monomeric diet in the rats with massive intestinal resection.
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1302
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Chen K, Gavaler JS, Van Thiel DH, Whiteside T. Phenotypic characterization of mononuclear infiltrate present in liver of biliary atresia. Dig Dis Sci 1989; 34:1564-70. [PMID: 2676428 DOI: 10.1007/bf01537111] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The liver tissue of 26 children with biliary atresia was compared to that of 20 adults with autoimmune chronic active hepatitis, 20 adults with chronic hepatitis due to hepatitis B infection, and 5 children with alpha 1-antitrypsin deficiency in terms of the number and type of mononuclear cells in portal and lobular areas of each using a panel of specific monoclonal antibodies that recognize different cell surface epitopes. All of the tissues studied were obtained at time of liver transplantation. In addition the livers of 5 adults biopsied for hepatomegaly but found to have no histologic liver disease were used as normal controls for this study. The results demonstrate that liver tissue obtained from children with end-stage biliary atresia is more like normal liver in terms of the number and type of mononuclear cells present than in either of the two types of adult liver diseases. Moreover although the liver of children with end-stage alpha 1-antitrypsin deficiency is more like that of normal liver than either of the two adult liver diseases studied in terms of the number and type of mononuclear cells within the liver, it is less similar to that of normal adult liver than is liver tissue obtained from children with biliary atresia. These findings suggest that as a morphologic basis biliary atresia is unlikely to be due to either a viral or an autoimmune attack upon the liver.
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1303
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Chen K, Swartz HM. The products of the reduction of doxyl stearates in cells are hydroxylamines as shown by oxidation by 15N-perdeuterated Tempone. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 992:131-3. [PMID: 2546601 DOI: 10.1016/0304-4165(89)90060-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The use of nitroxides in functional biological systems has increased greatly as it has become evident that such studies can provide valuable biophysical and metabolic data. This has led to a need to understand the nature of the metabolism of nitroxides and their products. This paper presents data indicating the value of 15N-perdeuterated Tempone specifically to indicate the amount of hydroxylamines that are present in a cellular system. Using this technique, we found that in the mammalian cells that we studied the principal or only products of reduction of doxyl stearates were the corresponding hydroxylamines.
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1304
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Chen K, Chen KJ, Sun FL. [Effects of an ever-young pill on decreased intelligence and symptoms associated with aging]. ZHONG XI YI JIE HE ZA ZHI = CHINESE JOURNAL OF MODERN DEVELOPMENTS IN TRADITIONAL MEDICINE 1989; 9:398-401, 387-8. [PMID: 2791157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A test was carried out to evaluate the effect of Ever-Young Pill (EYP) on decreased fluid intelligence and symptoms associated with aging. Nootropil and placebo were used as control drugs. Random, single-blind and self-control observation methods were applied. 90 days were spent for the clinical study. 154 older persons were divided into three groups (EYP 63, nootropil 60, placebo 31). The method of measuring intelligence was talking between man and computer. The computerized program was worked out by our department. The measure included eight parameters. A semi-quantitative method was used to evaluate the symptoms of aging. The main results were as follows: In the group of EYP, there were significant differences (P less than 0.01) in speed of calculation (SC, 5.92 +/- 2.5, 5.1 +/- 2.1), speed of digits and pictures (SDP, 24.2 +/- 6.2, 21.7 +/- 6.7), two digits span (2.8 +/- 1.0, 3.2 +/- 0.8) and other two parameters before and after treatment. In the group of nootropil, SDP and SC were also improved significantly. In the normal control's there was not any evident change. In the early declined health group treated with EYP and nootropil separately, four parameters were improved in each group. The best effect of EYP obtained was on Kidney Yang deficiency and Kidney and Heart Qi Yang deficiency Syndromes. In other syndromes, the results were less satisfactory. By using EYP for treating symptoms of aging the total effective rate was 96.8%, nootropil 71.7% and placebo 44.2%. There were noticeable differences in three groups. Those results suggested that EYP was one of the effective therapies for decreased fluid intelligence with aging.
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1305
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Mroczkowski B, Reich M, Chen K, Bell GI, Cohen S. Recombinant human epidermal growth factor precursor is a glycosylated membrane protein with biological activity. Mol Cell Biol 1989; 9:2771-8. [PMID: 2789334 PMCID: PMC362742 DOI: 10.1128/mcb.9.7.2771-2778.1989] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
NIH 3T3 cells were transfected with cDNA corresponding to human kidney prepro-epidermal growth factor (preproEGF) under control of the inducible mouse metallothionein promoter. The synthesis of recombinant human EGF precursor by these cells has provided us with a model system for analysis of the structure and activity of this precursor. In transfected cells, the precursor was present as an intrinsic 170-kilodalton membrane protein as well as a soluble protein in the extracellular medium; both forms were N glycosylated. Glycosylation of the EGF precursor was determined by (i) the direct incorporation of [3H]mannose and [3H]glucosamine, (ii) metabolic labeling in the presence or absence of glycosylation inhibitors, (iii) enzymatic cleavage of the precursor by N-glycanase or endoglycosidase II, and (iv) lectin chromatography. Recombinant human preproEGF was purified by affinity chromatography, using wheat germ lectin and antibodies to human EGF. The intact precursor was biologically active. Purified preparations of preproEGF (i) competed with 125I-labeled EGF for binding to the EGF receptor in intact fibroblast cells, (ii) activated the intrinsic tyrosine kinase activity of the EGF receptor in membrane preparations, and (iii) sustained the growth of a mouse keratinocyte cell line that is dependent on EGF for growth. These results suggest that proteolytic processing of the precursor may not be essential for its biological function.
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1306
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Snyderman CH, Heo DS, Chen K, Whiteside TL, Johnson JT. T-cell markers in tumor-infiltrating lymphocytes of head and neck cancer. Head Neck 1989; 11:331-6. [PMID: 2502505 DOI: 10.1002/hed.2880110408] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Fresh suspensions of tumor-infiltrating lymphocytes (TIL) from 16 patients with squamous cell carcinoma of the head and neck (SCCHN) were examined for T-cell markers including CD4 (helper-inducer), CD8 (cytotoxic-suppressor), natural killer (NK) cell, and activation surface markers using monoclonal antibodies and two-color flow cytometry. Two of 8 (25%) patients with a CD4/CD8 ratio of less than 1 developed cervical lymph node metastases; none had extracapsular spread. Six of 8 (75%) patients with a CD4/CD8 ratio of greater than 1 developed cervical metastases; 5 of 6 (83%) exhibited extracapsular spread. An increased CD4/CD8 ratio was attributable to a decrease in CD8+ cells. A CD4/CD8 ratio of greater than 1 may be a useful prognostic indicator of the development of cervical metastases.
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1307
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Chuang HR, Chen KM. A numerical method for the computation of induced currents inside 3-D heterogeneous biological bodies by ELF--LF electric fields. IEEE Trans Biomed Eng 1989; 36:628-34. [PMID: 2731949 DOI: 10.1109/10.29458] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A numerical technique, based on the combination of surface-charge integral equations (SCIE) and an impedance network method, has been developed to compute internal electric fields and currents inside 3-D heterogeneous biological bodies with arbitrary grounding impedances induced by ELF-LF electric fields. The method has been applied to a biological concentric-sphere and the numerical results agree well with an existing analytical solution. Numerical results of the induced current inside a simplified heterogeneous model of the human head computed by this method are also presented.
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1308
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Chen K. Bit-serial realizations of a class of nonlinear filters based on positive Boolean functions. ACTA ACUST UNITED AC 1989. [DOI: 10.1109/31.90399] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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1309
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1310
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Chen DG, Feng QP, Wang ZQ, Chen K. [Pharmacodynamics and pharmacokinetics of nifedipine in patients with congestive heart failure]. ZHONGGUO YAO LI XUE BAO = ACTA PHARMACOLOGICA SINICA 1989; 10:233-8. [PMID: 2609994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Twenty-seven cases of congestive heart failure (CHF) were treated with nifedipine (Nif) 20 mg po. Significant improvements in resting hemodynamics were found in 22 cases. The higher the basal systemic vascular resistance (SVR) and pulmonary artery end diastolic pressure (PAEDP) were, the greater the magnitudes of reduction found (r = 0.84 and 0.77, P less than 0.01, respectively). Exercise hemodynamic investigation showed that Nif led to a lowering of SVR, PAEDP and pulmonary vascular resistance (PVR), with increases in SV and concentration of 5-10 ng/ml, with a maximum being observed at the concentration of 20 ng/ml. No further vasodilation was found when the plasma concentration exceeded 20 ng/ml. No remarkable deviations from the normal ranges of Nif pharmacokinetics were found in CHF patients. The plasma norepinephrine level decreased markedly 2 and 7 h after Nif. Thus, it is concluded that oral Nif is beneficial in severe CHF patients having low cardiac output and high SVR.
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1311
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Sun JS, Wang SM, Chen KT, Lee CS, Chen KM. Angiodysplasia of the gastrointestinal tract: report of 5 cases and review of the literature. TAIWAN YI XUE HUI ZA ZHI. JOURNAL OF THE FORMOSAN MEDICAL ASSOCIATION 1989; 88:400-3. [PMID: 2794941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
With the application of more refined examinations, angiodysplasia is now being recognized as a common cause of bleeding in patients suffering from lower gastrointestinal bleeding. The diagnosis can be made by angiography or occasionally by colonofiberscopy. Angiography allows one to make this diagnosis even after bleeding has ceased. The lesions may not be clinically evident at the time of surgery, and the diagnosis must be made preoperatively to allow for proper treatment. A right hemicolectomy is the treatment of choice since these lesions are frequently multiple and seldom, if ever, occur distal to the proximal transverse colon. The pathophysiology, diagnosis, management and salient features of these lesions are described. The management of 5 patients is discussed.
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1312
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Luckhardt SC, Chen K, Coda S, Kesner J, Kirkwood R, Lane B, Porkolab M, Squire J. Production and maintenance of high poloidal beta tokamak plasmas by means of rf current drive. PHYSICAL REVIEW LETTERS 1989; 62:1508-1511. [PMID: 10039692 DOI: 10.1103/physrevlett.62.1508] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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1313
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Chen K, Glockner JF, Morse PD, Swartz HM. Effects of oxygen on the metabolism of nitroxide spin labels in cells. Biochemistry 1989; 28:2496-501. [PMID: 2543442 DOI: 10.1021/bi00432a022] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The products of the reduction of nitroxides in cells are the corresponding hydroxylamines, which cells can oxidize back to the nitroxides in the presence of oxygen. Both the reduction of nitroxides and the oxidation of hydroxylamines are enzyme-mediated processes. For lipid-soluble nitroxides, the rates of reduction are strongly dependent on the intracellular concentration of oxygen; severely hypoxic cells reduce nitroxides more rapidly than cells supplied with oxygen. In contrast, the rates of oxidation of hydroxylamines increase smoothly with increasing intracellular oxygen concentration up to 150 microM. In order to separate the effects on the rates of metabolism of nitroxides due directly to oxygen from effects due to the redox state of enzymes, we studied the cells under conditions in which each of these variables could be changed independently. Oxygen affects the metabolism of these nitroxides primarily by interacting with cytochrome c oxidase to change the redox state of the enzymes in the respiratory chain. Our results are consistent with the conclusions that in these cells reduction of lipophilic nitroxides occurs at the level of ubiquinone in the respiratory chain in mitochondria, and oxidation of the corresponding hydroxylamines occurs at the level of cytochrome c oxidase.
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1314
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Wang Q, Chen K, Hamilton TT, Ruderman M, Shaham J. Does supernova 1987A contain a rapidly vibrating neutron star? Nature 1989. [DOI: 10.1038/338319a0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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1315
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Chen K, Hiramatsu Y, Yunoki M, Hirano Y. [Focal sparing around the gallbladder in fatty liver: an useful sign in the diagnosis of borderline cases by CT]. NIHON IGAKU HOSHASEN GAKKAI ZASSHI. NIPPON ACTA RADIOLOGICA 1989; 49:146-52. [PMID: 2755781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The role of CT in the diagnosis of fatty liver is well established. CT has been proved to be a useful noninvasive tool for the demonstration of fatty infiltration of the liver. The characteristic finding is a diffuse decrease in the attenuation within the liver compared with that of the spleen. Commonly, fatty infiltration of the liver is generalized and both CT scans and sonograms can easily demonstrate changes related to this condition. Sometimes, fatty infiltration of the liver is focal and occasionally, it is generalized with focal sparing of the normal liver tissue creating some problems in the diagnosis. Recently, some reports have mentioned the appearance of a focal sparing area in the generalized fatty liver. We often found a high attenuation region around the gallbladder bed in the fatty liver patients on CT examination. There appears to be some relationship between the high density around the gallbladder area and the fatty liver. A retrospective study was undertaken to evaluate the relationship. In this paper, we presented the CT scans of 57 fatty liver cases and compared them with the CT scans of 50 normal patients to discuss the possible cause of the phenomenon and its usage in the diagnosis of the fatty liver.
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1316
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Lee WJ, Chang KJ, Hung CR, Chen KM. A case of acute superior mesenteric embolism successfully treated by embolectomy. TAIWAN YI XUE HUI ZA ZHI. JOURNAL OF THE FORMOSAN MEDICAL ASSOCIATION 1989; 88:176-8. [PMID: 2769217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Superior mesenteric artery embolism is undoubtedly fatal unless operative intervention is promptly performed. The first case successfully managed by embolectomy in Taiwan is reported in this communication. The key to successful management lies in the early suspicion in patients with atrial fibrillation or recent myocardial infarction, presenting with sudden abdominal pain and an unremarkable physical examination. Abdominal angiography is strongly recommended; however, immediate laparatomy should not be postponed if angiography is not available. Early embolectomy is the only useful means of treatment to restore mesenteric circulation, preserve the bowel and rescue the patient. A 56-year-old woman was admitted with a 5-year history of rheumatic heart disease and atrial fibrillation. She had a sudden attack of severe abdominal pain 8 hours after cardiac catheterization. Abdominal examination was not remarkable and plain abdominal X-ray was negative, while bloody stools and leukocytosis developed 7 hours later. Superior mesenteric embolism was highly suspected and emergency laparotomy was performed. Successful embolectomy was carried out through the distal approach and the patient recovered completely without requiring small bowel resection. All branches of the superior mesenteric artery were demonstrated patent upon postoperative angiography.
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1317
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Chen K. [Evaluation of mailed epidemiologic inquiries]. ZHONGHUA LIU XING BING XUE ZA ZHI = ZHONGHUA LIUXINGBINGXUE ZAZHI 1989; 10:47-50. [PMID: 2736613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The mailed inquiry is a economical and useful epidemiologic survey method. Comparison and discussion of data from the mailed inquiries and home interviews were done. More than 60 items which included general questions, height and weight, sources of drinking water, dietary habits, histories of smoking and alcohol consumption, physical activities, medical histories, parents medical histories and income were analysed, there was no significant difference in 45 items of the above data and a very significant relative coefficients between there two methods. Only 16 items which focused on alcohol and oil consumption, income, etc. had significant differences, but the most still had positive-relative correlation (P less than 0.05). The response rate of the mailed inquiries was 87.1 percent. In addition, the mailed questionnaire also was discussed.
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1318
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Chen K, Neimark H, Rumore P, Steinman CR. Broad range DNA probes for detecting and amplifying eubacterial nucleic acids. FEMS Microbiol Lett 1989; 48:19-24. [PMID: 2469620 DOI: 10.1016/0378-1097(89)90139-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
In this report we describe and characterize two oligomer probes that are broadly homologous to conserved eubacterial 16S ribosomal RNA (rRNA) sequences not present in human 18 rRNA or human mitochondrial 12S rRNA. One or both of the probes can detect all of 23 phylogenetically diverse eubacterial nucleic acids against which they were tested by dot blot hybridization. A sensitivity of about 1 bacterium per 10 eukaryotic cells was achieved. By using these oligomer sequences or their complements as primers in the polymerase chain reaction (PCR), the equivalent of 1 pg of E. coli DNA was detected in the presence of a large excess of eukaryotic DNA. Information useful for partial phylogenetic classification of detected organisms may be obtained by direct sequence analysis of the amplified DNA and comparison with known sequences or catalogs. Such broadly homologous probes offer advantages over more narrowly specific probes for detecting organisms whose identity is unknown. They could thus be employed for recognizing infection by organisms that cannot be cultured as may occur, for example, in tissue culture or in plant or animal diseases of unknown cause, provided the probes fail to hybridize with host nucleic acids.
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1319
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Takagi S, Chen K, Schwarz R, Iwatsuki S, Herberman RB, Whiteside TL. Functional and phenotypic analysis of tumor-infiltrating lymphocytes isolated from human primary and metastatic liver tumors and cultured in recombinant interleukin-2. Cancer 1989; 63:102-11. [PMID: 2642728 DOI: 10.1002/1097-0142(19890101)63:1<102::aid-cncr2820630117>3.0.co;2-t] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Tumor-infiltrating lymphocytes (TIL) were isolated from 40 of 51 consecutive human liver tumor samples (primary hepatocellular carcinoma, 16 of 18; metastatic, 23 of 29; benign, one of four). Functional and phenotypic characteristics of fresh and recombinant interleukin-2 (rIL-2)-expanded TIL were evaluated. The expansion of TIL from hepatic tumors in the presence of 1000 units/ml of rIL-2 was possible in 60% of cases. In comparison to TIL from metastatic liver tumors, TIL obtained from primary liver tumors expanded faster and better in rIL-2 cultures. Expanded TIL from primary tumors had significantly higher cytotoxicity against K562 targets, but not Raji targets, than those from metastatic tumors. Cytotoxicity against fresh autologous tumor targets was detected in seven of eight cultures tested. TIL from primary tumors retained antitumor reactivity significantly longer in culture. The optimal in vitro cytotoxicity was achieved between days 20 and 60 of culture in the presence of rIL-2. Antitumor activity was associated with the increase in these TIL cultures of a cell population expressing the Leu19 antigen with or without the CD3 antigen. The frequency of the CD3+Leu19+ population showed a bimodal distribution during culture: the first peak of CD3+Leu19+ cells occurred between days 30 and 60 and was associated with the increased antitumor activity; the second peak occurred after day 60 and was not associated with activity. These findings demonstrate that TIL from most human hepatic tumors can be successfully isolated, cultured in rIL-2, and enriched in Leu19+ effectors. In addition, these TIL upon IL-2 activation in vitro are capable of lysing fresh autologous and/or allogeneic tumor targets.
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1320
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Chen K, Ebner C, Jayaprakash C, Pandit R. Microemulsions in oil-water-surfactant mixtures: Systematics of a lattice-gas model. PHYSICAL REVIEW. A, GENERAL PHYSICS 1988; 38:6240-6254. [PMID: 9900383 DOI: 10.1103/physreva.38.6240] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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1321
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Abstract
Over a 2-year period we have identified pollen grains from 48 families of grasses, as well as mould spores and mite particles during air sampling in Guangxi Province. The major aeroallergens were Artemisia, Moraceae and Euophoribiacea, and the spores of Aspergillus, Penicillinum, Cephalosporium and Helminthosporium. Mites were probably also one of the major outdoor aeroallergens. Our investigations also included inspection of the vegetation of the geographical area involved, as well as skin testing on 774 subjects using extracts of 37 aeroallergens. We believe that this work has provided fundamental information on seasonal allergy in Southern China and South-east Asia.
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1322
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Chen K, Liang P, Yu M, Chang ST. A New Double-Stranded RNA Virus from Volvariella volvacea. Mycologia 1988. [DOI: 10.2307/3807565] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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1323
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Haldar P, Chen K, Maheswaran B, Roig-Janicki A, Jaggi NK, Markiewicz RS, Giessen BC. Bulk Superconductivity at 122 K in T1(Ba,Ca)
2
Ca
3
Cu
4
O
10.5+δ
with Four Consecutive Copper Layers. Science 1988; 241:1198-200. [PMID: 17740783 DOI: 10.1126/science.241.4870.1198] [Citation(s) in RCA: 95] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The observed increase of superconducting transition temperature (T(c)) with the number of copper oxide planes continues in the four-[CuO(2)](-2) layer (single TI layer) oxide superconductor, which has been prepared with > 80% purity and was magnetically aligned for crystallographic identification. A master scaling curve is proposed, which ties together the T(c)'s of virtually all known Bi and Tl oxide superconductors, and shows that the Tl(Bi) layers play an essential role in the superconductivity. publication 350 of the Barnett Institute.
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1324
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Chen K, Morse PD, Swartz HM. Kinetics of enzyme-mediated reduction of lipid soluble nitroxide spin labels by living cells. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 943:477-84. [PMID: 3415989 DOI: 10.1016/0005-2736(88)90380-x] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Nitroxide spin labels can be reduced to the corresponding hydroxylamines in cells. The selective action of inhibitors, and thermal and chemical inactivation demonstrate that the reduction of nitroxides in cells is an enzymatic or enzyme-mediated process. The kinetics of reduction of doxylstearates are affected by the position of the doxyl moiety along the stearic acid chain. The doxyl moiety of 5-doxylstearate is close to the membrane surface, and its reduction is first order with respect to the nitroxide, whereas the doxyl moieties of 10- and 12-doxylstearate are in the membrane hydrocarbon region and their reduction is a zero-order process. The reduction of 16-doxylstearate which usually has a mixture of first- and zero-order kinetics becomes zero order with addition of an extracellular broadening agent, potassium trioxalatochromiate(III). These results suggest that the rate of reduction of doxyl moieties is controlled by their accessibility to reducing equivalents, i.e., the rate-limiting step for the reduction of the doxyl moiety deep in the membrane is the diffusion of reducing equivalents within or into the membrane. The reduction of doxylstearates in cells is inhibited by rotenone but not antimycin A, cyanide, propyl gallate or SKF-525A. It appears that the reduction of doxylstearates takes place at the level of the ubiquinone in the respiratory chain in mitochondria in these cells.
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1325
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Chen K, Swartz HM. Oxidation of hydroxylamines to nitroxide spin labels in living cells. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 970:270-7. [PMID: 2840969 DOI: 10.1016/0167-4889(88)90126-7] [Citation(s) in RCA: 69] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In the presence of oxygen, cells can oxidize hydroxylamines, which are the products of the reduction of nitroxides in cells, back to nitroxides. Lipid-soluble hydroxylamines are oxidized much more rapidly than water-soluble ones, and most of this oxidation is inactivated by heat or trichloroacetic acid, indicating that the principal mechanism is enzyme-linked. The rates of oxidation of some lipophilic hydroxylamines are comparable to the rates of reduction of the corresponding nitroxides. Hydroxylamines formed by reduction of aqueous soluble nitroxides are not oxidized by cells, except for slight oxidation of some pyrrolidine derivatives. The latter is due to autoxidation. The kinetics of oxidation of reduced lipid-soluble nitroxides are all first-order with respect to hydroxylamines, regardless of the position of the nitroxide group along the carbon backbone, indicating that the oxidation occurs within the membrane. The oxidation of hydroxylamines in cells in inhibited by cyanide but not by antimycin A or SKF-525A. We also describe an effective method to oxidize hydroxylamines and follow this reaction; the method is based on the use of perdeuterated [15N]Tempone.
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