Biomedical subjects

Y Yu

Publications and source records attributed to Y Yu.

At least 451 records · Page 25Linked to original sources

PubMed1996

Reduction of circulating prostaglandin E2 level by antiserum against core lipopolysaccharide in a rabbit model of multiple organ failure.

OBJECTIVE: To determine the potential role of prostaglandin E2 (PGE2) in the development of multiple organ dysfunction or failure (MOF), the possible effects of antiserum directed against Re chemotype lipopolysaccharide (LPS, from Re mutant of Escherichia coli F515) on circulating PGE2 level and survival rate, and whether there is an elevation in the plasma LPS concentration that could account for the induction of arachidonic acid metabolite in a rabbit model of MOF caused by acute hypovolemic insult. DESIGN, MATERIALS, AND METHODS: An animal model of MOF in rabbits, engendered by feeding live Escherichia coli O111:B4 before hemorrhagic shock (35-40 mm Hg for 60 min), was used in the present study. Re-LPS antiserum was given intravenously in the treatment group at the onset of hemorrhage and 4 hours after resuscitation. The animals that received equal volumes of normal rabbit serum and antiserum served as the control group. MEASUREMENTS AND MAIN RESULTS: The circulating PGE2 level was not increased at the end of shock (p > 0.05), but it was found to be significantly elevated 24 hours after hemorrhage and resuscitation in both groups. However, Re-LPS antiserum administration markedly decreased peak PGE2 level (p < 0.05) and attenuated multiple organ damage caused by acute insult. Concomitantly, there were also lower LPS concentrations in the treatment group as compared with the control group (p < 0.05-0.01). The survival rate was significantly increased in antiserum-treated rabbits 96 hours postinjury (treatment vs. control: 58.0% vs. 11.1%, p < 0.01). CONCLUSIONS: The results suggest that an excessive generation and release of PGE2 may be involved in the pathogenesis of immunosuppression and MOF following hemorrhage and resuscitation. Re-LPS antiserum has an inhibitory effect on overproduction of circulating PGE2 and the ability to improve survival with MOF. Gut-derived endotoxemia, bacterial translocation, or both, could account, at least in part, for the PGE2 formation and release in animals response to acute hypovolemic insult.

Animals↗

PubMed1996

A nondivergent specification of the mean treatment dose in interstitial brachytherapy.

The harmonic mean formalism is investigated as a nondivergent specification of the mean treatment dose in three distinct applications of interstitial brachytherapy: (a) permanent 125I prostate implant; (b) double plane 192Ir linear source array; and (c) multiple catheter optimized high dose rate implant. In each case the harmonic treatment dose (HTD) can be calculated in regions that contain radioactive sources or otherwise high dose gradient, to yield objective and consistent results with little computational effort. The need to identify local dose minima, geometric centers, or seed planes is largely avoided, which makes the formalism suitable for automated computation. Dose distribution uniformity is analyzed in terms of the fractional spread for the HTD and, where the periphery of the target volume is delineated, the uniformity number and the peripheral uniformity number. It is shown that the harmonic mean dose formalism is a practical alternative to the ICRU dose specification parameters in certain areas of brachytherapy.

Biometry↗

PubMed1996

A genetic algorithm for the optimization of prostate implants.

A genetic algorithm (GA) is presented for the optimization of template- and ultrasound-guided prostate implants. The end points for optimization are incorporated in an objective function of separable cardinal utility terms. As an application of the GA, the minimum 103Pd total source strength required to deliver a given dose was correlated with the average dimension for prostate implants carried out under the current template and seed spacing protocols. Significant improvements in quality were observed, in terms of both the minimum peripheral dose and tumor cell surviving fractions, when GA-optimized implants were compared to the corresponding unoptimized implants for given target volumes. In addition, numerical simulation of source displacements indicates that the dosimetric and radiobiologic advantages of GA optimization can tolerate a reasonable level of seed placement uncertainties observed clinically. In summary, the GA application provides an automated design strategy for prostate implant planning, and at the same time affords the potential for systematic optimization of a set of end points that can sustain practical variations.

Algorithms↗

PubMed1996

Mutations in the homologous ZDS1 and ZDS2 genes affect cell cycle progression.

The Saccharomyces cerevisiae ZDS1 and ZDS2 genes were identified as multicopy suppressors in distinct genetic screens but were found to encode highly similar proteins. We show that at semipermissive temperatures, a yeast strain with a cdc28-1N allele was uniquely deficient in plasmid maintenance in comparison with strains harboring other cdc28 thermolabile alleles. Quantitative analysis of plasmid loss rates in cdc28-1N strains carrying plasmids with multiple replication origins suggests that a defect in initiating DNA replication probably causes this plasmid loss phenotype. The ZDS1 gene was isolated as a multicopy suppressor of the cdc28-1N plasmid loss defect. A zds1 deletion exhibits genetic interactions with cdc28-1N but not with other cdc28 alleles. SIN4 encodes a protein which is part of the RNA polymerase II holoenzyme-mediator complex, and a sin4 null mutation has pleiotropic effects suggesting roles in transcriptional regulation and chromatin structure. The ZDS2 gene was isolated as a multicopy suppressor of the temperature-sensitive growth defect caused by the sin4 null mutation. Disruption of either ZDS1 or ZDS2 causes only modest phenotypes. However, a strain with both ZDS1 and ZDS2 disrupted is extremely slowly growing, has marked defects in bud morphology, and shows defects in completing S phase or entering mitosis.

Adaptor Proteins, Signal Transducing↗

PubMed1996

Molecular markers of ionizing radiation-induced gene mutations in mammalian cells.

We have isolated independent Chinese hamster ovary (CHO) cell mutants at the hypoxanthine guanine phosphoribosyltransferase (hprt) locus from untreated, 60Co gamma-ray-exposed, and 212Bi alpha-exposed cells and identified the molecular changes underlying the mutation determined by multiplex polymerase chain reaction (PCR)-based exon deletion analysis. Both the parental CHO-K1 cells and the X-ray-sensitive mutant xrs-5 cells were studied. The radiosensitive xrs-5 cells are defective in DNA double-strand break rejoining ability and in V(D)J recombination, which can be complemented by Ku protein. Of the 71 spontaneous CHO-K1 hprt mutants analyzed, 78% showed no change in exon number or size, 20% showed loss of one to eight exons (partial deletion), and 3% showed loss of all nine hprt exons (total deletion). Exposure of CHO-K1 cells to 6 Gy of gamma rays, which reduced survival levels to 10%, produced a high deletion spectrum with 45% of the 20 mutants analyzed showing a loss of one to eight exons and 30% showing total deletion. Exposure to an equitoxic dose of alpha radiation from 212Bi, a 220Rn daughter, resulted in a spectrum similar to the gamma-ray spectrum in that 75% of the 49 mutants analyzed were deletions. To alpha radiation, however, tended to produce larger intragenic deletions than gamma radiation. Of the 92 spontaneous xrs-5 mutants analyzed for deletions, 43% showed a loss of one to eight exons and 14% showed total deletion. This suggests that, in certain regions of the hprt gene, base alterations can be converted into large deletions and alteration in the Ku protein complex can influence this type of mutational process. Exposure to alpha radiation (10% survival) to xrs-5 cells resulted in a deletion spectrum similar to that seen in CHO-K1 cells. Of the 49 mutants analyzed, 43% showed on change in exon number or size, 16% showed a loss of one to eight exons, and 41% showed total deletion. While the defect in xrs-5 cells has a profound effect on spontaneous mutant spectra, this defect does not appear to affect alpha-induced mutation spectra.

Alpha Particles↗

PubMed1996

Clinical significance of the increased peak levels of exhaled nitric oxide in patients with bronchial asthma.

We measured exhaled nitric oxide (NO) with a chemiluminescence method to elucidate the clinical significance of the increased concentration of exhaled NO in patients with bronchial asthma. Exhaled NO was measured in 25 patients with bronchial asthma and in 10 healthy control subjects. The concentration of exhaled NO in asthmatics was significantly higher than in the controls (250.4 +/- 30.4,59.9 +/- 9.6 ppb, respectively, p < 0.01). Symptomatic patients (unstable asthmatics) had a higher exhaled NO concentration than did the asymptomatic patients (stable asthmatics) (384.2 +/- 32.5,143.6 +/- 18.8 ppb, respectively, p < 0.01). The exhaled NO concentration was significantly correlated with the peak expiratory flow rate (r = 0.671, p < 0.01) and eosinophil ratio in induced sputum (r = 0.772, p < 0.05), but it was not correlated with the parameters of bronchial hyperactivity (Dmin and PD35 Grs). We conclude that the increased concentration of exhaled NO in patients with bronchial asthma reflects the state of airway inflammation, and we suggest that the measurement of exhaled NO is a useful, non-invasive and simple method for the management of bronchial asthma.

Adult↗

PubMed1996

Acupuncture stimulation enhances splenic natural killer cell cytotoxicity in rats.

Acupuncture stimulation of the anterior tibial muscle, which is equivalent to Tsu-sanli point (S36) stimulation and which induces acupuncture analgesia, enhanced YAC-1 cell lytic activity of the splenic natural killer cells (NK activity) from pentobarbital anaesthetized Wistar rats. On the other hand, abdominal muscle stimulation, which does not induce acupuncture analgesia, did not affect NK activity. The serum from rats treated with acupuncture stimulation (acupuncture-stimulated rats) also enhanced the NK activity of other intact rats. The reinforcement effect of serum remained after heat inactivation (56 degrees C, 30 min). The serum from acupuncture-stimulated rats also had more potent complement activity than that from control rats. These results indicate the following considerations: 1) the Tsu-sanli point may be one of the specific points modulating immune activity, 2) this immune modulation system may share a common nervous pathway with the acupuncture analgesia-producing system, 3) acupuncture stimulation may modify NK activity through unknown heat stable humoral factors as well as the nervous system, and 4) acupuncture stimulation may activate the complement system.

Animals↗

PubMed1996

[The effect of cytokines on the liver necrosis].

OBJECTIVE: To investigate the effect of cytokines on liver necrosis. METHODS: We injected IL-1, IL-6, IFN gamma, TNF alpha with or without D-galactosamine (D-GAL) into the abdominal cavity of mice separately. RESULTS: There was no effect on hepatocyte of normal mice after injection of IL-1, IL-6, IFN gamma alone or together. The serum total bilirubin (TBIL) and liver necrosis of mice increased more markedly by using of TNF alpha, IL-6 or IFN gamma separately with D-GAL (TBIL: 46.2 +/- 10.6 micromol/L, 44.6 +/- 12.9 micromol/L, 41.9 +/- 14.9 micromol/L), then by D-GAL alone (TBIL: 27 +/- 11 micromol/L) also the serum TBIL of mice and liver necrosis also increased after injection of IL-1, IL-6 with D-GAL and TNF alpha. CONCLUSION: Cytokines like IL-1, IL-6, IFN gamma and TNF alpha joined the process of hepatocyte necrosis. They can enhance the degree of liver necrosis induced by D-GAL.

Animals↗

PubMed1996

Detection of PML-RAR alpha in patients with APL during follow-up period.

OBJECTIVE: To evaluate the significance of PML-RAR alpha transcripts in patients with acute promyelocytic leukemia (APL) during remission period and to follow up the patients through monitoring aberrant gene expression. PATIENTS AND METHODS: This study included 17 patients with APL (5 females and 12 males). Another 19 APL patients during relapse served as control. RNA extraction was obtained through the single-step method. By means of reverse transcriptase polymerase chain reaction (PCR), the PML-RAR alpha was detected in the sample mRNA. RESULTS: Nine out of 10 patients with complete remission (CR) duration shorter than 3 years were positive. Four cases became negative and three remained positive among 7 cases in a long remission of over 3 years. The difference of the positive rate of PML-RAR alpha transcripts between the 2 groups was significant (P < 0.05). Four among 12 positive cases relapsed. No evidence of relapse was present in the 5 negative patients after 9.6 +/- 3.9-month follow-up. Further treatment was therefore given to the 4 positive patients whose treatment was already ceased at that time. By this management they were all in CR during the following 10-month observation. CONCLUSIONS: RT-PCR detection for PML-RAR alpha transcripts was useful in monitoring MRD and guiding further treatment to obtain a long remission. Persistently positive transcripts were closely associated with the relapse.

Adolescent↗

PubMed1996

Use of recombinant Epstein-Barr virus early antigen for detection of antibody in patients with nasopharyngeal carcinoma.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is one of the most common cancers in southern China and Taiwan. Serological studies revealed the close-relationship between NPC and Epstein-Barr virus (EBV). Elevated serum and saliva levels of anti-EBV antibodies are detected in patients with NPC. Therefore, Development Center for Biotechnology prepared the EBV-early antigen (EA-D) by recombinant DNA technique for screening the serum and throat washing samples from patients with head and neck cancers. METHODS: The BMRF1 gene for EBV early antigen (EA-D) was placed into the plasmid pDB18, then transformed into an Escherichia coli strain containing the lambda cI857 temperature-sensitive repressor. Heat treatment of the transformant, at exponential growth phase, inactivated the cI protein and induced an over-expression of the EA-D protein. Next, the EA-D was purified by chromatography and characterized as a protein of molecular weight 47 kDa, by sodium dodecyl sulfate-polyacry lamide gel electrophoresis (SDS-PAGE) and Western blot analysis using monoclonal anti-EA antibody and sera from patients with nasopharyngeal carcinoma (NPC). Enzyme-linked immunosorbent assay (ELISA) with the purified EA-D antigen was used to screen 129 serum and throat washing (TW) samples from patients with head and neck tumors, 24 from patients with a nonmalignant disease and 44 from normal donors. RESULTS: Experimental results indicated significantly higher positive rates of EA-D IgA (69%) and EA-D IgG (91%) in NPC sera than in the sera of patients with other head and neck tumors and normal controls. TW samples from patients with NPC also showed a higher positive rate (34%) than the other groups (7-20%). CONCLUSIONS: Results in this study demonstrate that the bacterially expressed EA-D antigen could be recognized by sera from patients with NPC and monoclonal anti-EA antibody. Thus, it has potential use in ELISA for screening EBV-related diseases such as NPC.

Antibodies, Viral↗

PubMed1996

Enhanced efficacy of combination of IL-2 gene and IL-6 gene-transfected tumor cells in the treatment of established metastatic tumors.

IL-2 and IL-6 are important cytokines which have potent antitumor effects and can cooperate to induce immune responses more effectively. IL-2 gene or IL-6 gene-transfected tumor cells exhibited reduced tumorigenicity and decreased metastatic potential. In order to increase the therapeutic efficacy of IL-2 gene-, IL-6 gene-modified tumor vaccines, the experimental pulmonary metastatic melanoma-bearing mice were treated with inactivated IL-2 gene-transfected tumor cells and inactivated IL-6 gene-transfected tumor cells. After the combined vaccination, the pulmonary metastases were reduced more significantly and the survival time of tumor-bearing mice was also markedly prolonged. The CTL activity, NK activity and IL-2-induced LAK activity, IL-2 and TNF secretion from the splenocytes of the above tumor-bearing mice increased more significantly than that of tumor-bearing mice vaccinated with IL-2 gene-transfected vaccine or IL-6 gene transfected vaccine alone. These results demonstrated that the combined use of IL-2 gene-transfected tumor vaccine and IL-6 gene-transfected tumor vaccine could achieve more potent antitumor effect via more effective activation of specific and non-specific antitumor immune responses.

Animals↗

PubMed1996

[An experimental study on injury of intestinal immuno-barrier in rat after scald].

A dynamic observation on injury of intestinal immuno-barrier in scalded rat was performed to investigate the relationship between the injury of intestinal immuno-barrier and bacterial translocation. After 40% TBSA third degree scald, a decrease of IgA in intestinal content and the number of CD3+ and CD4+ T lymphocyte, and reduction of IgA coat rate of intestinal bacteria were observed. At the same time, an increase in the incidence of bacterial translocation was detected. The results indicated that intestinal immuno-barrier was damaged and its protective function was weakened after an extensive thermal injury, and it suggested that the injury of intestinal immuno-barrier might play an important role on the development of postburn bacterial translocation and postburn sepsis.

Animals↗

PubMed1996

Colchicine reduces hepatic fibrosis in mice infected with Schistosoma japonicum.

OBJECTIVE: Colchicine has been used clinically to treat hepatic cirrhosis caused by multiple etiologies. MATERIALS AND METHODS: The effect of colchicine on the liver fibrosis of mice infected with Schistosoma japonicum were studied. The morphological observation and morphometric analysis of the infected and untreated, and infected and treated groups were proceeded under the light microscopy, and morphological observation was made under electron microscopy. RESULTS: The results of morphometriic analysis in histological sections showed that the collagen fibers area per schistosome's egg was decreased in the infected and treated groups 10 to 13 weeks after infection. The decrease in the group of 13 weeks was significant statistically. The egg numerical density on area increased continuously from 10 to 13 weeks in both untreated and treated groups in similar degree. The ultrastructural study showed the accumulation of collagen fibrils around the hepatocytes and in the space of Disse decrease and ultrastructural lesion of hepatocytes get recovery in the treated group. CONCLUSIONS: These findings suggest that colchicine has therapeutic effect on schistosomal liver fibrosis, through not only killing off the schistosome but interfering the metabolism of collagen.

Animals↗

PubMed1996

[The in vitro antitumor responses of murine peritoneal macrophages induced by adenovirus-mediated IL-4 and/or M-CSF gene therapy].

OBJECTIVE: To observe the antitumor responses of murine peritoneal macrophages induced by adenovirus-mediated IL-4 and/or M-CSF gene transfer. METHODS: The IL-4 gene and/or M-CSF gene was transfected into murine peritoneal macrophages-mediated by adenovirus and the levels of IL-4, M-CSF, TNF, IL-1 and NO in the supernatant of the macrophages and the cytotoxicity of the macrophages to tumor cells were assayed. RESULTS: The high levels of IL-4 and M-CSF could be detected in the supernatant of macrophages 18 hours after being infected with advenovirus expressing IL-4 or M-CSF. The cytotoxicity of the macrophages engineered to secrete IL-4 or M-CSF increased significantly, and when IL-4 gene and M-CSF gene were cotransfected into the macrophages or the macrophages were co-stimulated with LPS, the cytotoxicity increased even more significantly. The levels of TNF, IL-land NO in the supernatant of macrophages also increased. CONCLUSION: The results demonstrated that transfection of IL-4 and/or M-CSF gene into macrophages could augment their anti-tumor immunity.

Adenoviruses, Human↗

PubMed1996

[The effect of tumor necrosis factor alpha on hepatic necrosis in viral hepatitis].

In order to investigate the effect of tumor necrosis factor alpha (TNF alpha) on hepatocyte necrosis in viral hepatitis, TNF alpha with or without D-galactosamine (D-Gal) was injected into the abdominal cavity of rats. No effect was observed after injection of TNF alpha alone. After injection of TNF alpha with D-Gal, the total bilirubin level in rat blood increased and hepatocyte necrosis appeared (P < 0.05). Moreover, anti-TNF alpha McAb blocked the effect of hepatocyte necrosis produced by D-Gal and lipopolysaccharide (LPS). 130 samples of hepatic tissue were stained with anti-TNF alpha McAb by using ABC immunohistochemistry method. It was found that more severe the hepatocyte necrosis, more the positive cells expressing TNF alpha. There were more TNF alpha positive cells in the tissue of severe hepatitis. These results suggested that TNF alpha is a mediator in hepatocyte necrosis.

Adult↗

PubMed1996

[Changing prognosis of primary liver cancer: some aspects to improve long-term survival].

The authors reported the changing prognosis of primary liver cancer (PLC) during the last three decades and the factors improving long-term results. Two thousand three hundred and eighty eight pathologically proven PLC cases were analyzed. Of them, 569 cases (23.8%) were small-sized PLC (< or = 5 cm in diameter). Hepatic resection was performed in 1,650 cases (69.1%) and local resection was done in 1,202 of the 1,650 (72.8%). Follow-up study was carried out every 2-3 months during the first 2 years after resection and every 6 months thereafter. For some unresectable huge PLC, cytoreduction and subsequent resection were performed. Five-year survival rate was 4.8% in 1958-1970 (n = 187), 11.2% in 1971-1982 (n = 582), and 45.7% in 1983-1994 (n = 1,628), respectively. Re-resection of subclinical recurrence was performed in 147 cases. Cytoreduction and subsequent resection were carried out in 71 cases. It is concluded that markedly changing prognosis of PLC was observed; factors improving long-term survival included (1) early detection and radical resection, (2) local resection instead of lobectomy, (3) re-resection for subclinical recurrence, and (4) cytoreduction and subsequent resection for otherwise unresectable PLC.

Adolescent↗

PubMed1996

[Long-term follow-up results of eleven cases after resection of hepatic metastases from colorectal cancer].

Eleven patients with hepatic metastases from colorectal cancer survived more than 5 years after the resection were reviewed. There were 3 (27.3%) disease-free survivors, the longest survival period was 7 years and 2 months. Compared with 41 survivors of less than 5-year duration after resection, it was shown that close follow-up after resection of the primary cancer, detecting early subclinical hepatic metastases, preoperative lower level of CEA, tumor less or equal to 5 cm in size, single metastatic nodule and radical resection were important factors influening long-term survival (P < 0.05). It is of the opinion that early diagnosis, early resection and re-resection after detecting subclinical local recurrence and metastases play important role in improving long-term response.

Adult↗

PubMed1996

[Improvement in model of mesangial proliferative glomerulonephritis of rat].

To establish a model of mesangial proliferative glomerulonephritis (MsPGN), we gave Sprague-Dawley rats staphylococcal enterotoxin B (SEB) intravenously twice in different times, bovine serum albumine (BSA) through digestive tract every other day, and Freud's adjuvant subcutaneously twice in different times, respectively. The results showed that measangial cells and matrix in glomeruli of rats began to proliferate at the end of 6th week and this change became obvious at the end of 8th week. The duration of experiment was shorter than that using only SEB, and the change of pathomorphology was stable. The experiment confirms the thesis that mucosal immunization of gastroenteric tract plays an important role in the development of MsPGN.

Animals↗