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P Lin

Publications and source records attributed to P Lin.

At least 109 records · Page 6Linked to original sources
PubMed1997

Neutralizing IGF-1 monoclonal antibody with cross-species reactivity.

We report the generation of a murine IGF-1 monoclonal antibody designated 35I17, which exhibits unique cross-species reactivity. The antibody recognizes recombinant human and rat IGF-1 in ELISA, Western blots, and in an 125I-recombinant human IGF-1 Scintillation Proximity Assay. In addition, 35I17 blocks cell proliferation induced by recombinant human and rat IGF-1, and inhibits cell proliferation induced by sera from human, rat, calf, dog, goat, or mouse. The antibody inhibits rat IGF-1 binding to IGF-1 receptors, and prevents IGF-1-stimulated receptor and IRS-1 phosphorylation in LISN C4 cells, an IGF-1 receptor-transfected cell line. The cross-species and neutralizing properties of 35I17 may be useful in in vitro and in vivo animal studies for elucidating the role of IGF-1 in cancer, rheumatoid arthritis, and other diseases.

3T3 Cells↗
PubMed1997

Analysis of mutationally altered forms of the Cct6 subunit of the chaperonin from Saccharomyces cerevisiae.

The Cct double-ring chaperonin complex of Saccharomyces cerevisiae is comprised of eight essential subunits, Cct1p-Cct8p, and assists the folding of substrates such as actins and tubulins. Single and multiple amino acid replacements of Cct6p were constructed by oligonucleotide-directed mutagenesis, including changes of charged to alanine residues and uncharged to charged residues. The replacements were targeted, in part, to residues corresponding to functionally critical regions identified in the published crystal structure of the Escherichia coli chaperonin, GroEL. Here, we report the critical hydrophobic residues and clusters of hydrophilic residues in regions corresponding to those from the apical domain of GroEL implicated in peptide binding and peptide release, and certain residues in the putative equatorial domain implicated in subunit-to-subunit interaction. In contrast to their homologous counterparts in Cct2p and Cct1p, the highly conserved putative ATP binding motifs of Cct6p were relatively amenable to mutations. Our data suggest that the entire Cct6p molecule might be essential for assembly of Cct complex and might participate in binding substrates. However, there appeared to exist a functional hierarchy in ATP binding/hydrolysis among Cct subunits, as suggested by the high tolerance of Cct6p to mutations within the putative ATP binding pocket.

Amino Acid Sequence↗
PubMed1997

[Reconstruction of the hypopharyngeal and cervical esophagus using flap of epiglottis].

Reconstruction of the hypopharyngeal and cervical esophagus was performed for eight patients after the resection of hypopharyngeal carcinoma. The flap of the epiglottis and the facial flap of the sternohyoid muscle or the uninvolved mucous membrane of the hypopharynx were used for the reconstruction of the hypopharyngeal and cervical esophagus. A good swallowing function was obtained. No pharyngeal-cervical fistula occurred. Although stomach transposition or colon interpolation and pectoralis major myocutaneous flap could be used to reconstruct the hypopharynx and the cervical esophagus, however, the operative time became longer, more complex and the patient suffered more. The procedure of the flap of epiglottis had the following advantages: (1) a rich vascularized flap; (2) simple operative technique; (3) higher success rate; and (4) few complications.

Adult↗
PubMed1997

[Study on red cell enzymes and isoenzymes in patients with leukemia and myelodysplastic syndromes].

OBJECTIVE: To define the prevalence of acquired red cell enzymopathy in leukemia and MDS patients and explore its clinical significance. METHODS: Red cell enzymes (G6PD, 6PGD, PK, ENOL, ADA, PNP,ALD) activities and PK,ADA isoenzymes were assayed by the methods recommended by ICSH and PAGE electrophoresis. RESULTS: The prevalence rate of G6PD deficiency was 43.1%, and of PK deficiency was 27.8%, in leukemia and MDS patients. The prevalence rates of PK, G6PD and PNP deficiency in MDS patients were 50%, 48% and 39.1%, respectively, while of ADA, ENOL and ALD over production in MDS patients were 69. 6%, 40% and 30. 4%, respectively. PK activity was increased in CML, while the PK isoenzyme pattern was normal. Administration of antitumor antibiotics to AL decreased G6PD and 6PGD activities (P < 0.05). ADA2 was expressed in MNC of AML (M4 and M5) and in RBC of CMML, but not expressed in ALL (P < 0.001). CONCLUSION: Determination of enzymes may be used as prognostic parameters in CML,a predictor of antitumor drug resistance in acute leukemia, and a differential parameter between MDS-RA and aplastic anemia and between CML and CMML.

Adolescent↗
PubMed1997

Does vaginal cuff closure decrease the infectious morbidity associated with abdominal hysterectomy?

BACKGROUND: Infectious morbidity after total abdominal hysterectomy includes fever (31%) and antibiotic administration (45%). Whether vaginal cuff closure reduces postoperative infectious morbidity remains unresolved. STUDY DESIGN: We reviewed the records of 172 consecutive abdominal hysterectomies for nonmalignant disease performed at an inner-city hospital. We identified potential risk factors for infectious morbidity by univariate analysis and determined adjusted odds ratios by multiple logistic regression analysis. RESULTS: The open vaginal cuff technique was associated with an increased risk of wound infection. Use of prophylactic antibiotics was associated with a decreased risk of febrile morbidity and a decreased risk of prolonged hospitalization. Body weight in the heaviest quartile was associated with increased risk of wound infection, increased risk of prolonged hospitalization, and decreased risk of postoperative vaginal cuff granulation tissue. Older age was associated with an increased risk of prolonged hospitalization. CONCLUSIONS: Closure of the vaginal cuff and use of prophylactic antibiotics at total abdominal hysterectomy were associated with decreased infectious morbidity in a high-risk population.

Antibiotic Prophylaxis↗
PubMed1997

[The shrinkage of ovarian and uterine size and the decline of serum estradiol level in post-menopausal women].

OBJECTIVE: To investigate the shrinkage of ovarian and uterine size, and the decline of serum estradiol (E2) level in normal women. METHODS: Ovarian and uterine area of 92 perimenopausal and 292 postmenopausal women, measured by transvaginal ultrasonography, were analysed retrospectively and were compared with those of the controls consisting of 41 normal women in midfollicular phase, so did the serum E2 levels. RESULTS: As compared with the control group, ovarian area and endometrium thickness shrunk on an average of 30%, 2% and 56%, 48% in early perimenopausal and postmenopausal groups respectively. Serum E2 level and uterine area increased by 11% and 38% in early perimenopausal group, but decreased by 67% and 21% in postmenopausal groups respectively. No obviously further decline of serum E2 level was found 1 year after menopause, and of ovarian, uterine area 3-5 years after menopause. CONCLUSION: These data represent a normal profile of ovarian and uterine shrinkage and decline of serum E2 levels related to the time of menopause.

Adult↗
PubMed1996

Failure to activate interleukin 1beta-converting enzyme-like proteases and to cleave retinoblastoma protein in drug-resistant cells.

We previously found that retinoblastoma (RB) is cleaved at the initiation of apoptotic execution. Here we report that when an HL-60 cell line resistant to cytosine arabinoside (Ara-C) was exposed to this anticancer drug, neither RB cleavage nor apoptosis was detected. Consistent with that, processing of interleukin 1beta-converting enzyme (ICE) and CPP32 (an ICE-like protease) was also prevented in these cells. In contrast, treatment of the HL-60-Ara-C-resistant cells with etoposide induced all of these apoptotic events. Furthermore, the etoposide-induced RB cleavage was inhibited by a specific tetrapeptide ICE-like inhibitor. Our results demonstrate that activation of the RB cleavage enzyme, an ICE-like protease, is required for overcoming drug resistance.

Caspase 1↗
PubMed1996

Formation of interstrand DNA cross-links by bis-(2-chloroethyl)sulfide (BCES): a possible cytotoxic mechanism in rat keratinocytes.

Interstrand cross-links in the DNA of epidermal basal keratinocytes may be responsible for cell death and consequent vesication in skin exposed to BCES. The formation of cross-links and cytotoxicity were compared when cells in primary monolayer cultures of rat epidermal keratinocytes, synchronized at the G1/S boundary or in the G1 phase of the cell cycle, were exposed to BCES. The dose-responsive formation of cross-links, measured with an ethidium bromide-fluorescence assay, was determined immediately after exposure of cells at either position of the cycle. At 24 hr post-exposure, the level of cross-links in cells exposed at the G1 phase showed had not decreased significantly and was still dose-dependent. However, cells exposed in the G1 phase showed a major decrease in cross-links. Formation of interstrand DNA cross-links appears to be related to the mustard's cytotoxicity.

Animals↗
PubMed1996

Somatic histone H1 microinjected into fertilized mouse eggs is transported into the pronuclei but does not disrupt subsequent preimplantation development.

We injected somatic subtypes of histone H1 into newly fertilized mouse eggs, which do not naturally contain this chromosomal protein, and examined the fate of the injected protein and its effect on preimplantation development of recipient eggs. Rhodamine-labelled H1 injected into the cytoplasm of 53 eggs was transported into the pronuclei in 51 cases, and this nuclear accumulation could be detected within 15 min of injection. Unlabelled histone H1, which was detected using immunofluorescence, was also transported following microinjection to the pronuclei, where it colocalized with the chromatin and remained associated with the nuclei following cleavage to the two-cell stage. Nuclear accumulation of injected H1 was inhibited when injected eggs were incubated in the presence of drugs that prevent mitochondrial electron transport or glycolysis, which indicates that nuclear transport occurs through an energy-dependent process, as previously observed in tissue culture cells. To determine whether the presence of somatic H1 in early embryonic nuclei would influence subsequent development, fertilized eggs were injected with an approximately physiological quantity (1-5 pg) of somatic H1 or, as controls, with another small basic protein, cytochrome c. Fifty-three eggs were injected with cytochrome c, of which 51 divided to the two-cell stage, and 32 (60%) reached the blastocyst stage, after 5 days in culture. One hundred and eleven eggs were injected with somatic H1, of which 95 divided to the two-cell stage, and 53 (48%) reached the blastocyst stage, after 5 days in culture. The two groups did not differ statistically (chi 2, P > 0.1) with respect to the fraction of injected embryos that developed to the blastocyst stage. These results show that, although mouse embryos lack the somatic subtypes of histone H1 until the four-cell stage of development, they are able to progress through preimplantation development when these subtypes are present beginning at the one-cell stage. This may imply that the distinctive chromatin composition that characterizes early embryos of a variety of species is not essential for early development in mammals.

Animals↗
PubMed1996

GABAA receptors modulate early spontaneous excitatory activity in differentiating P19 neurons.

P19 embryonic carcinoma (EC) stem cells are pluripotent and are efficiently induced to differentiate into neurons and glia with retinoic acid (RA) treatment. Within 5 days, a substantial number of differentiating P19 cells express gene products that are characteristic of a neuronal phenotype. P19 neurons were used as a model to explore the relationship between neuronal "differentiation" in vitro and the acquisition of gamma-aminobutyric acid (GABAA) receptors and functional GABA responses. Pulse-labeling experiments using bromodeoxyuridine indicated that all neurons had become postmitotic within 3-4 days after treatment with RA. This was confirmed by a reduction in the immunocytochemical detection of the undifferentiated stem cell antigen SSEA-1. Subsequently, a transient expression of nestin was observed during the first 5 days in vitro (DIV) after exposure to RA. By 5-10 DIV after RA, a significant number of neurons (approximately 80-90%) expressed immunocytochemically detectable glutamate decarboxylase and GABA coincident with the acquisition of membrane binding sites for tetanus toxin. These phenotypic markers were maintained for > 30 DIV after RA. Under current-clamp conditions, random, low-amplitude, spontaneous electrical activity appeared in neurons within the first few days after RA treatment and this was blocked by the specific GABAA receptor antagonist bicuculline. Thereafter, the appearance and progressive increases in the frequency of spontaneous action potentials in P19 neurons were observed that were similarly attenuated by bicuculline. In neurons > 5 DIV after RA, exogenous application of GABA elicited similar action potentials. The onset of excitatory responses to GABA or muscimol in voltage-clamped neurons appeared immediately after the cessation of neuronal mitosis and before the previously reported acquisition of responses to glutamate. In fura-2 imaging studies, the exogenous application of GABA resulted in neuron-specific increases in intracellular Ca2+. Thus, P19 neurons provide an in vitro model for the study of the early acquisition and properties of electrical excitability to GABA and the expression of functional GABAA receptors.

Action Potentials↗
PubMed1996

[The influence on prognosis of intraoperative chemotherapy for adenocarcinoma of gastric cardia].

Four hundred and four patients underwent surgical treatment for adenocarcinoma of the gastric cardia in our hospital between January 1980 to June 1990. Of 342 resected cases, 231 cases were treated with surgery alone, their 1-, 3-, and 5-year survival rates were 83.8%, 38.5% and 20.8%, respectively. Since January 1987, postoperative chemotherapy was given in 47 patients, their 1-, 3-, and 5-year survival rates were 89.4%, 46.8%, 29.8%, respectively, while intraoperative chemotherapy in 54 cases, had 1-, 3-, and 5-year survival rates of 87.1%, 63.0% and 38.9%, respectively. The result showed that the 3- and 5-year survival rates were higher in postoperative chemotherapy cases than in cases with operation alone, but there was no statistical significance between the two groups. However, intraoperative chemotherapy group had much higher 3- and 5-year survival rates than operation alone (P < 0.01). Intra-operative chemotherapy is recommended especially in patients beyond stage I with lymph node metastasis.

Adenocarcinoma↗
PubMed1996

[Clinical study of the pattern of lymphnode metastasis in carcinoma of esophagus: an analysis of 200 cases].

To study the pattern of lymphnode metastasis in carcinoma of the esophagus, 200 cases of resected esophageal cancer specimens were carefully examined pathologically. Lymphnode metastasis, its pathway and extent in relation to pathological changes were analyzed. Lymphnode metastasis was mainly regional and extended vertically in both directions. Leaping-over metastasis was another feature. The deeper invasion by the tumor, the higher frequencies of metastasis development, and vice versa. However, leaping-over metastasis was more likely to occur where tumor invasion was less severe. Owing to the high frequency of lymphnode metastasis in the superior mediastinum and the widely spanned leaping-over metastases, an operative approach by three incisions through right thoracotomy with excision of the whole segment of esophagus and anastomosis at cervical region was recommended, in order to dissect lymphnodes in the cervical, thoracic and abdominal regions and to leave less or no metastatic lymphnodes behind.

Adult↗
PubMed1995

The complete sequence of human lens gamma s-crystallin.

The complete sequence of human gamma s-crystallin has been determined and confirmed using a combination of MS methods, peptide sequencing and cDNA sequencing. Regions 21-35 and 102-107, which were previously assumed to be the same as the bovine sequence, differ from the bovine sequence at residues 22, 28, 31 and 104. An additional six residues were also found to be different from the original sequence determined for Pakastani lenses. Whether these differences represent errors in the original sequence or two different sequences among human lens crystallins is not yet known.

Amino Acid Sequence↗
PubMed1995

Human IL-12 p40 homodimer binds to the IL-12 receptor but does not mediate biologic activity.

IL-12, a heterodimeric cytokine, consists of two disulfide-linked subunits, p40 and p35. We investigated the role of p40 in ligand binding and signal transduction by expressing this subunit alone in COS cells. Culture media of the transfected COS cells exhibited specific dose-dependent binding to KIT225/K6 cells, a human T cell line that expresses IL-12R. Analysis of the culture media by SDS-PAGE and Western blotting demonstrated the presence of 40-kDa monomers and 80-kDa disulfide-linked homodimers. The two p40 species were purified and identified by N-terminal sequencing and proteolytic peptide mapping. Characterization of the p40 proteins for binding and bioactivity showed that both the p40 monomer and dimer inhibited 125I-labeled IL-12 binding to IL-12R, but the 80-kDa species, having a 50% inhibitory concentration (IC50) of 20 to 70 ng/ml, was at least 20-fold more effective than the monomer. Although neither the monomer nor the dimer stimulated human PHA-blast proliferation, the 80-kDa dimer inhibited IL-12-induced proliferation in a dose-dependent manner with an IC50 of 65 ng/ml. The results suggest that the IL-12 p40 subunit contains the essential epitopes for receptor binding. However, a proper conformation required for high affinity binding is achieved only when p40 is associated with a p35 subunit or another p40 subunit. When p40 is associated with a p35 subunit, the heterodimer acts as an agonist mediating biologic activity. However, when p40 associates with another p40, the homodimer behaves as an antagonist in vitro.

Animals↗
PubMed1995

Excision of ovarian dermoid cyst by laparoscopy and by laparotomy.

OBJECTIVES: Our purpose was to evaluate the efficacy of laparoscopic ovarian dermoid cystectomy and to compare the operative course, postoperative course, and complications between the laparoscopy and the laparotomy techniques. STUDY DESIGN: The safety and efficacy of laparoscopic ovarian dermoid cystectomy were evaluated in 40 women. Twenty-nine of 40 patients underwent laparoscopic excision of a solitary dermoid cyst without any additional procedure. The operative course, the postoperative course, and complications among these 29 women were compared with those of 26 other women who underwent a similar procedure by laparotomy. RESULTS: Spillage of the cyst's content did not lead to any complication. The operating time in the laparoscopy group was 73.5 +/- 4.7 minutes and in the laparotomy group it was 41.4 +/- 2.9 minutes. The duration of hospitalization was significantly shorter in the laparoscopy group (0.7 +/- 0.2 days) than in the laparotomy group (3.8 +/- 0.1 days). CONCLUSIONS: Although ovarian dermoid cystectomy by laparoscopy is associated with a longer operating time than by laparotomy, the duration of hospitalization is shorter and recovery is faster. Spillage of the contents of the dermoid cyst does not lead to any complication; perhaps this is due to the liberal irrigation of the peritoneal cavity.

Adult↗
PubMed1994

Tcp20, a subunit of the eukaryotic TRiC chaperonin from humans and yeast.

Members of the Hsp60 chaperonin family, such as Escherichia coli GroEL/S and the eukaryotic cytosolic chaperonin complex, TRiC (TCP ring complex), are double toroid complexes capable of assisting the folding of proteins in vitro in an ATP-dependent fashion. TRiC differs from the GroEL chaperonin in that it has a hetero rather than homo-oligomeric subunit composition and lacks a GroES-like regulatory cofactor. We have established greater than 57% identity between a protein encoded by the TCP20 gene from a human cDNA library and the newly identified protein encoded by the TCP20 gene located on the right arm of chromosome IV of the yeast Saccharomyces cerevisiae. These Tcp20 proteins showed approximately 30% identity to Tcp1, a known subunit of TRiC. Gel filtration, followed by Western analysis of purified bovine testis TRiC with a Tcp20-specific antibody, indicated that Tcp20 is a subunit of the hetero-oligomeric TRiC. Gene disruption experiments showed that TCP20, like TCP1, is an essential gene in yeast, consistent with the view that TRiC is required for folding of key proteins. The amino acid sequence similarities and the derived evolutionary relationships established that the human and yeast Tcp20 proteins represent members of a new family of subunits of TRiC chaperonins.

Amino Acid Sequence↗
PubMed1994

Temporal regulation of the IgE-dependent 1,2-diacylglycerol production by tyrosine kinase activation in a rat (RBL 2H3) mast-cell line.

We explored the possible role of tyrosine kinases in the IgE-dependent regulation of 1,2-diacylglycerol (DAG) production in RBL 2H3 cells. When triggered via their high-affinity IgE receptors (Fc epsilon RI), there was a rapid phosphorylation of tyrosine residues on a number of proteins. The phosphorylation of these proteins and ultimately histamine release were inhibited in a concentration-dependent manner by the tyrosine kinase inhibitor, tyrphostin. In cells labelled with [3H]myristic acid, we observed a characteristic biphasic increase in [3H]DAG production. In the presence of tyrosine kinase inhibitor, the initial increase in DAG was still observed, but the secondary increase, which was dependent on phosphatidylcholine-specific phospholipase D (PC-PLD) activation, was completely abolished. Tyrphostin significantly inhibited IgE-dependent activation of PC-PLD, suggesting that PC-PLD activation was regulated by tyrosine phosphorylation. Furthermore, when proteins from RBL 2H3 cells were immunoprecipitated with an anti-phosphotyrosine antibody, PC-PLD activity was recovered from the immunoprecipitated fraction. These results demonstrate that the secondary, but not the initial, phase of 1,2-DAG production in response to Fc epsilon RI aggregation is regulated by the initial activation of tyrosine kinases and that PC-PLD may be regulated directly by this mechanism.

Animals↗