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Biomedical subjects

S Zhao

Publications and source records attributed to S Zhao.

At least 235 records · Page 13Linked to original sources
PubMed1999

A novel immunoscintigraphy technique using metabolizable linker with angiotensin II treatment.

Immunoscintigraphy is a tumour imaging technique that can have specificity, but high background radioactivity makes it difficult to obtain tumour imaging soon after the injection of radioconjugate. The aim of this study is to see whether clear tumour images can be obtained soon after injection of a radiolabelled reagent using a new linker with antibody fragments (Fab), in conditions of induced hypertension in mice. Fab fragments of a murine monoclonal antibody against human osteosarcoma were labelled with radioiodinated 3'-iodohippuryl N-epsilon-maleoyl-L-lysine (HML) and were injected intravenously to tumour-bearing mice. Angiotensin II was administered for 4 h before and for 1 h after the injection of radiolabelled Fab. Kidney uptake of 125I-labelled-HML-Fab was much lower than that of 125I-labelled-Fab radioiodinated by the chloramine-T method, and the radioactivity of tumour was increased approximately two-fold by angiotensin II treatment at 3 h after injection, indicating high tumour-to-normal tissue ratios. A clear tumour image was obtained with 131I-labelled-HML-Fab at 3 h post-injection. The use of HML as a radiolabelling reagent, combined with angiotensin II treatment, efficiently improved tumour targeting and enabled the imaging of tumours. These results suggest the feasibility of PET scan using antibody fragment labelled with 18F-fluorine substitute for radioiodine.

Angiotensin II↗
PubMed1999

Expression of Bcl-2-related genes in normal and AML progenitors: changes induced by chemotherapy and retinoic acid.

The expression of Bcl-2 family members was examined in normal and leukemic hematopoietic cells. Immature hematopoietic progenitor cells (CD34+/33-/13-) did not express Bcl-2 but Bcl-XL, the majority of CD34 cells expressed Bcl-2, Bcl-XL and BAD, and normal promyelocytes (CD34-/33+) lacked expression of both Bcl-2 and Bcl-XL, while leukemic CD34+progenitors and promyelocytes expressed these anti-apoptotic proteins. In AML, Bcl-2 expression was higher on CD34+ than on all AML cells, however, expression of Bcl-2 or Bcl-XL did not predict achievement of complete remission. Surprisingly, low Bcl-2 content was associated with poor survival in a group of patients with poor prognosis cytogenetics. The anti-apoptotic BAD protein was found to be expressed in AML, but was phosphorylated in 41/42 samples. Phosphorylation was found at both sites, Ser 112 and Ser 136. During induction chemotherapy, Bcl-2 levels of CD34 cells increased significantly. In the context of evidence for small numbers of leukemic CD34+ cells expressing very high levels of Bcl-2 prior to therapy, this finding is interpreted as a survival advantage of Bcl-2 overexpressing progenitors and rapid elimination of cells with low Bcl-2. Bcl-2 and Bcl-XL were both expressed in minimal residual disease cells. Downregulation of Bcl-2 mRNA and protein was observed by ATRA and the combination of Ara-C, followed by ATRA, resulted in markedly increased cytotoxicity in HL-60 cells, as compared to Ara-C alone or ATRA followed by Ara-C. Implications of these findings for the development of new therapeutic strategies for AML are discussed.

Acute Disease↗
PubMed1999

Functional expression of TRAIL by lymphoid and myeloid tumour cells.

TRAIL is a potent death protein that favours the killing of various types of cancer cells to normal cells, but under the right conditions TRAIL can also kill activated human T cells. TRAIL mRNA is widely expressed by normal cells but its expression by primary tumour cells is not known. In this study, primary tumour cells of haemopoietic origin constitutively expressed TRAIL mRNA and protein and were capable of inducing the apoptosis of target Jurkat cells in a dose-dependent manner. This killing effect was reversed by anti-TRAIL antibody. The functional expression of TRAIL by lymphoid and myeloid malignant cells raises the possibility of its involvement in tumour cell evasion of immunosurveillance, and could be related to spontaneous tumour cell death and necrosis.

Apoptosis↗
PubMed1999

Hippocampal Cajal-Retzius cells project to the entorhinal cortex: retrograde tracing and intracellular labelling studies.

Cajal-Retzius (CR) cells are characteristic horizontally orientated, early-generated transient neurons in the marginal zones of the neocortex and hippocampus that synthesize the extracellular matrix protein reelin. They have been implicated in the pathfinding of entorhino-hippocampal axons, but their role in this process remained unclear. Here we have studied the axonal projection of hippocampal CR cells. Following injection of the carbocyanine dye DiI into the entorhinal cortex of aldehyde-fixed rat embryos and young postnatal rats, neurons in the outer molecular layer of the dentate gyrus and stratum lacunosum-moleculare of the hippocampus proper with morphological characteristics of CR cells were retrogradely labelled. In a time course analysis, the first retrogradely labelled CR cells were observed on embryonic day 17. This projection of hippocampal CR cells to the entorhinal cortex was confirmed by retrograde tracing with Fast Blue in new-born rats and by intracellular biocytin filling of CR cells in acute slices from young postnatal rat hippocampus/entorhinal cortex and in entorhino-hippocampal slice cocultures using infrared videomicroscopy in combination with the patch-clamp technique. In double-labelling experiments CR cells were identified by their immunocytochemical staining for reelin or calretinin, and their interaction with entorhino-hippocampal axons labelled by anterograde tracers was analysed. Future studies need to investigate whether this early transient projection of hippocampal CR cells to the entorhinal cortex is used as a template by the entorhinal axons growing to their target layers in the hippocampus.

Amidines↗
PubMed1999

A test of the Piagetian water-level task with Chinese students.

A sample of 486 children in Beijing, China, were tested on the water-level task (WLT; J. Piaget & B. Inhelder, 1948/1956). The participants were 256 boys and 230 girls from 4th, 5th, 6th, 8th, and 11th grades. Three levels of mastery of the WLT were found. Level 1 consisted of 4th and 5th graders, who averaged about 71% correct. Level 2 consisted of 6th and 8th graders, who averaged about 83% correct. Level 3 consisted of 11th graders, who averaged 97% correct. The results provide partial support for the Piagetian theory of age-related developmental differences in performance on the WLT. The findings depict an interactive relationship of maturation with culture and education in the development of the ability to solve the WLT.

Adolescent↗
PubMed1999

Radioimmunotherapy for liver micrometastases in mice: pharmacokinetics, dose estimation, and long-term effect.

The pharmacokinetics of a therapeutic dose of 131I-labeled antibody and the absorbed dose in liver micrometastases of human colon cancer LS174T in female BALB/c nu/nu mice were investigated, along with the long-term therapeutic effect. Mice with liver micrometastases were given an intravenous injection of 131I-labeled anti-carcinoembryonic antigen (CEA) antibody F33-104 (8.88 MBq/ 40 microg). The biodistribution of the antibody was determined 1, 2, 4, 6, and 10 days later. The absorbed dose was estimated for three hypothetical tumor diameters; 1,000, 500, and 300 microm. Autoradiography showed a homogeneous distribution of radioactivity in the micrometastases, and a high uptake was maintained until day 6 (24.0 % injected dose (ID)/g on day 1 to 17.8 %ID/g on day 6), but decreased thereafter. The absorbed doses in the 1,000-, 500-, and 300-microm tumors were calculated to be 19.1, 12.0, and 8.2 Gy, respectively. The intravenous injection of the 131I-labeled antibody also showed a dose-dependent therapeutic effect (all mice of the nontreated group died, with a mean survival period of 4 weeks; 3 of the 8 mice that received 9.25 MBq survived up to 120 days with no sign of liver metastasis). These data give further evidence that micrometastasis is a good target of radioimmunotherapy, and that an absorbed dose of less than 20 Gy can effectively control small metastatic lesions.

Animals↗
PubMed1999

Effect of ambient temperature on human skeletal muscle metabolism during fatiguing submaximal exercise.

To examine the effect of ambient temperature on metabolism during fatiguing submaximal exercise, eight men cycled to exhaustion at a workload requiring 70% peak pulmonary oxygen uptake on three separate occasions, at least 1 wk apart. These trials were conducted in ambient temperatures of 3 degrees C (CT), 20 degrees C (NT), and 40 degrees C (HT). Although no differences in muscle or rectal temperature were observed before exercise, both muscle and rectal temperature were higher (P < 0.05) at fatigue in HT compared with CT and NT. Exercise time was longer in CT compared with NT, which, in turn, was longer compared with HT (85 +/- 8 vs. 60 +/- 11 vs. 30 +/- 3 min, respectively; P < 0.05). Plasma epinephrine concentration was not different at rest or at the point of fatigue when the three trials were compared, but concentrations of this hormone were higher (P < 0.05) when HT was compared with NT, which in turn was higher (P < 0.05) compared with CT after 20 min of exercise. Muscle glycogen concentration was not different at rest when the three trials were compared but was higher at fatigue in HT compared with NT and CT, which were not different (299 +/- 33 vs. 153 +/- 27 and 116 +/- 28 mmol/kg dry wt, respectively; P < 0.01). Intramuscular lactate concentration was not different at rest when the three trials were compared but was higher (P < 0.05) at fatigue in HT compared with CT. No differences in the concentration of the total intramuscular adenine nucleotide pool (ATP + ADP + AMP), phosphocreatine, or creatine were observed before or after exercise when the trials were compared. Although intramuscular IMP concentrations were not statistically different before or after exercise when the three trials were compared, there was an exercise-induced increase (P < 0.01) in IMP. These results demonstrate that fatigue during prolonged exercise in hot conditions is not related to carbohydrate availability. Furthermore, the increased endurance in CT compared with NT is probably due to a reduced glycogenolytic rate.

Adult↗
PubMed1999

Purine loss after repeated sprint bouts in humans.

The influence of the number of sprint bouts on purine loss was examined in nine men (age 24.8 +/- 1.6 yr, weight 76 +/- 3.9 kg, peak O(2) consumption 3.87 +/- 0.16 l/min) who performed either one (B1), four (B4), or eight (B8) 10-s sprints on a cycle ergometer, 1 wk apart, in a randomized order. Forearm venous plasma inosine, hypoxanthine (Hx), and uric acid concentrations were measured at rest and during 120 min of recovery. Urinary inosine, Hx, and uric acid excretion were also measured before and 24 h after exercise. During the first 120 min of recovery, plasma inosine and Hx concentrations, and urinary Hx excretion rate, were progressively higher (P < 0.05) with an increasing number of sprint bouts. Plasma uric acid concentration was higher (P < 0.05) in B8 compared with B1 and B4 after 45, 60, and 120 min of recovery. Total urinary excretion of purines (inosine + Hx + uric acid) was higher (P < 0. 05) at 2 h of recovery after B8 (537 +/- 59 micromol) compared with the other trials (B1: 270 +/- 76; B4: 327 +/- 59 micromol). These results indicate that the loss of purine from the body was enhanced by increasing the number of intermittent 10-s sprint bouts.

Adult↗
PubMed1999

Past-year use of outpatient services for psychiatric problems in the National Comorbidity Survey.

OBJECTIVE: The authors present nationally representative descriptive data on 12-month use of outpatient services for psychiatric problems. They focused on the relationship between DSM-III-R disorders and service use in four broadly defined service sectors as well as the distribution of service use in multiple service sectors. METHOD: Data from the National Comorbidity Survey were examined. RESULTS: Summary measures of the seriousness and complexity of illness were significantly related to probability of use, number of sectors used, mean number of visits, and specialty treatment. One-fourth of the people in outpatient treatment were seen in multiple service sectors, but no evidence was found of multisector offset in number of visits. CONCLUSIONS: Use of outpatient services for psychiatric problems appears to have increased over the decade between the early 1980s and early 1990s, especially in the self-help sector. Aggregate allocation of treatment resources was related to need, highlighting the importance of making provisions for specialty care in the triage systems currently evolving as part of managed care.

Adolescent↗
PubMed1999

The relationship of glycosylation and isoelectric point with tumor accumulation of avidin.

UNLABELLED: Radiolabeled avidin markedly accumulated in intraperitoneal tumors and was cleared rapidly from circulation when given intraperitoneally. This study investigated the mechanisms of the tumor localization of avidin. METHODS: Avidin was deglycosylated through endoglycosydase-H digestion and/or neutralized by acetylation of its lysine amino acids with acetic acid N-hydroxysuccinimide ester. Avidin and modified avidins were analyzed using sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS/PAGE) and isoelectric focusing. A tumor model was established by intraperitoneal injection of human colon cancer cells, LS180, in nude mice. Avidin and modified avidins were labeled with 111In using diethyleneamine pentaacetic acid-biotin and were administered intraperitoneally into the tumor-bearing mice. The biodistribution of radioactivity was examined 2 and 24 h postinjection. RESULTS: Deglycosylated avidins revealed a major band of smaller molecules on SDS/PAGE. The isoelectric point of neutralized avidins was reduced to less than 5, whereas that of unneutralized avidins was more than 9.5. Biodistribution study demonstrated that liver uptake was decreased by deglycosylation and kidney accumulation was decreased by neutralization, respectively. The blood clearance was remarkably slowed by combined modification of deglycosylation and neutralization. The tumor uptake of radioactivity was reduced by either deglycosylation or neutralization and was further decreased with combined modification. CONCLUSION: Both high glycosylation and positive charge of avidin contributed to its accumulation in tumor. This study may facilitate development of a new vehicle for the delivery of therapeutic agents to intraperitoneal tumors.

Animals↗
PubMed1999

[Study of NAIP gene in spinal muscular atrophy].

OBJECTIVE: Investigating the correlation between the genotype and spinal muscular atrophy(SMA) clinical phenotype. METHODS: Neuronal apoptosis inhibitory protein(NAIP) gene analysis was performed by PCR amplification of exon 5 in 13 unrelated SMA patients with deletions of SMN gene. RESULTS: Two Type-I patients(2 M5, 40%) lacked the NAIP exon 5. CONCLUSION: The results suggest a possible correlation between NAIP gene deletion and the disease severity of SMA.

Child↗
PubMed1999

[Isolating candidate inserted fragment from positive fused phage clones using quantitative PCR].

OBJECTIVE: To isolate quickly and exactly the specific inserted fragment from fused phage clones which were obtained from cDNA library by hybridization. METHODS: According to the amplification principle of quantitative polymerase chain reaction (PCR) and based on the difference of original template quantity,target cDNA fragment was isolated and identified by two PCRs. RESULTS: A positive clone with specific cDNA fragment of HumGT-H1 gene was obtained from a two-phage fused clone by using this method,and the inserted fragment was verified to be the 5' cDNA sequence of HumGT-H1,1.9kb in length. So another hybridization screening is not necessary. CONCLUSION: The method presented is effective and rapid in gene cloning and can greatly save time and materials.

Bacteriophages↗
PubMed1999

Apoptosis. Molecules and mechanisms.

This review of the molecules and pathways involved in programmed cell death (apoptosis) discriminates triggers of apoptosis (e.g. chemotherapy, radiation, Fas ligation), modulators of apoptosis (e.g. Bcl-2 family members, Bcl-2 interacting proteins, Apafs, IAPs, and Fas/FasL modulators including FLICE and FLIPs), effectors (caspases 1-13) and cleavage substrates (e.g. PARP). Special consideration is given to the structure-function relationship of Bcl-2 family members and to their post-transcriptional modification. Brief references are made to the role of apoptotic pathway in leukemias and lymphomas and to strategies of modulating apoptotic pathways.

Animals↗
PubMed1999

[The establishment and application of genomic DNA extraction from peripheral blood].

OBJECTIVE: To establish the method of genomic DNA extraction. METHODS: Genomic DNA was directly extracted from peripheral blood with the use of potassium iodide. RESULTS: The genomic DNA extracted with potassium iodide was of large molecular weight. A(260)/A(280) and A(260)/ A(230) were 1.85 and 2.2 respectively. The extraction efficiency was greater than 90%. The result of PCR for the DNA was good. CONCLUSION: The method is simple, quick, economical and could be used for studying numbers of clinical samples.

DNA↗
PubMed1999

[Prevalence of HCV and HBV infection in patients with primary hepatocellular carcinoma in Shanxi Province].

OBJECTIVE: To study the prevalence of hepatitis C and B viruses (HCV and HBV) infection in the patients with primary hepatocellular carcinoma (PHC) in Shanxi Province and evaluate their etiologic roles in the pathogenecity of PHC to lay a foundation for the prevention and control of it. METHODS: Ninety-eight patients with PHC and 196 non-PHC controls matched in age and sex were selected from the four hospitals at provincial level in Shanxi Province. Serum antibodies against HCV (anti-HCV), HBs (anti-HBs), HBe (anti-HBe) and HBc (anti-HBc), IgM-antibody against HBc (anti-HBc-IgM), HBsAg and HBeAg were determined for all of them with enzyme-linked immunosorbent assay (ELISA). RESULTS: Positivity for anti-HCV and rate of HBV infection were 8.16% and 63.37%, respectively, in the PHC patients, both significantly higher than those in the controls (P < 0.05), with attributable risk proportions of (ARP) 94%, and 91%, respectively. Multiple conditional logistic regression analysis showed that positive serum anti-HCV, HBsAg and anti-HBc a risk factors for PHC, all entered the regression model, with odds ratios (ORs) of 55.06, 10.18 and 9.85, respectively. Dichotomized contingency table analysis showed that OR for those positive both for anti-HCV and HBsAg was 61.37, significantly higher than that for single positive of either one, with an additive effect. CONCLUSION: It suggested that both HCV and HBV infection were main etiologic factors for PHC in local. HBV also was an important factor in the pathogenecity of PHC, especially in those with both positive for HBsAg and anti-HBc. Coinfection with HBV and HCV had an additive effect on PHC pathogenecity.

Carcinoma, Hepatocellular↗
PubMed1999

[Effect of space environment on physiological state in Carthamus tinctorius L].

OBJECTIVE: To substantiate te effect of weightlessness and heavy ion radiation in space environment on medicinal plants. METHODS: The seeds of medicinal plant Carthamus tinctorius were carried aboard a retrievable satellite during 3-18 July, 1994. After returning to earth, the changes of peroxidase and protein were studied by means of electrophoresis. RESULTS: The result showed that the peroxidase activity of each group of seeds which were hit and penetrated by heavy ions rays was higher than that of the ground controlled seeds, but slightly lower than that of the weightless seeds. The protein contents of the weightless seeds and the seeds which is penetrated once and less than once by heavy ions rays were higher than those of the seeds which were kept on earth, but the seeds which were penetrated 2-3 times by heavy ion rays were lower than those of the ground controlled seeds. The peroxidase isozyme and protein patterns of the weightless seeds were similar to those of the ground controlled seeds, but very different between the heavy ion ray penetrated seeds and the earth kept seeds. CONCLUSION: It follows that the weightlessness in space environment has an effect mainly on the physiological condition of plants, but the heavy ion radiation has a stronger effect on the hereditary basis of plants.

China↗
PubMed1999

[Effects of space flight on medicinal plant Agastache rugosa (Fisch. et Mey.) O. Ktze].

OBJECTIVE: To substantiate the effect of space conditions on medicinal plants. METHODS: The seeds of Agastache rugosa were set up in retrievable satellites. After returning to earth, the changes of isozymes of peroxidases, esterase and soluble proteins were studied. RESULTS: The peroxidase activity and protein content of the weightless group were a little lower than those of the earth controlled group, while these two items of the hit group were higher than those of the earth controlled group. The electrophoresis patterns of isoperoxidases and isoeasterase of these three groups, as well as the protein patterns of the weightless group and the earth controlled group were found alike. But the protein patterns of the hit group were different from those of the other two groups. CONCLUSION: The effect of weightlessness is smaller than that of the high energy heavy ions on Agastache rugosa. Different plants have different susceptibility to space conditions.

China↗