Rotational behavior in intermediate energy heavy ion collisions.
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Journal Article↗
Biomedical subjects
J Feng
Publications and source records attributed to J Feng.
High-resolution analysis of c-fos chromatin accessibility using a novel DNase I-PCR assay.
In our previous study, c-fos chromatin accessibility was assayed using DNase I digestion and Southern blot analysis. This low-resolution mapping of c-fos chromatin accessibility demonstrated that serum stimulation of the c-fos enhancer induces a reversible increase in c-fos DNase I sensitivity and suggested that a 5' to 3' gradient of DNase I sensitivity may form downstream from the c-fos enhancer. To confirm the existence of a 5' to 3' gradient of accessibility, we have recently developed a high-resolution polymerase chain reaction (PCR) assay for DNase I sensitivity. Using this novel DNase I assay, we have reliably detected position- and time-dependent gradients of chromatin accessibility around the c-fos enhancer. These data confirm our earlier results and further support the hypothesis that the changes in c-fos chromatin accessibility originate near the 5' enhancer. As a technique for future examinations of gene structure, our data demonstrate the value of the DNase I-PCR assay for rapidly preparing comprehensive and high-resolution maps of chromatin accessibility for any sequenced genomic region.
Base Sequence↗
An altered repertoire of fos/jun (AP-1) at the onset of replicative senescence.
With multiple divisions in culture, normal diploid cells suffer a loss of growth potential that leads to replicative senescence and a finite replicative capacity. Using quantitative RT-PCR, we have monitored mRNA expression levels of c-fos, c-jun, JunB, c-myc, p53, H-ras, and histone H4 during the replicative senescence of human fibroblasts. The earliest and the largest changes in gene expression occurred in c-fos and junB at mid-senescence prior to the first slowing in cell growth rates. The basal level of c-fos mRNA decreased to one-ninth that of the early-passage levels, while junB declined to one-third and c-jun expression remained constant. The decline in the basal c-fos mRNA level in mid-senescence should lead to an increase in Jun/Jun AP-1 homodimers at the expense of Fos/Jun heterodimers and may trigger a cascade of further changes in c-myc, p53, and H-ras expression in late-passage senescent fibroblasts.
Base Sequence↗
Clinical evaluation of radioimmunoimaging with 131I-C0C183B2 monoclonal antibody against ovarian carcinoma by intraperitoneal injection.
Forty-eight cases subjected to radioimmunoimaging (RII) by intraperitoneal injection with 131I-C0C183B2 monoclonal antibody (MAb) prepared in our laboratory were studied. Thirteen of 14 cases of proved primary ovarian carcinoma were positive. In 11 follow-up cases of ovarian carcinoma after initial surgery and chemotherapy, 5 recurrences were positive and 6 cases without recurrence were negative; all were confirmed histopathologically after a second operation. One false negative was ovarian mucinous adenocarcinoma, which also negatively stained with C0C183B2 by the peroxidase anti-peroxidase method. Twenty of 23 cases of nonepithelial or metastatic carcinoma of the ovary, benign tumors, and benign diseases were negative. The sensitivity and specificity were 94.7 and 89.7%, respectively. If patients had complications with ascites, the MAb which positively stained with the cancer cells in the ascites was chosen for RII. For follow-up cases PAP staining with the tumor tissue from the initial surgery and the MAb should be done before RII. These are the principal factors that increase the positive rate and accuracy of RII. The intraperitoneal route seems to be a valuable method for clinical staging and tumor localization as well as for follow-up use.
Adult↗
Role of phosphorylated metabolic intermediates in the regulation of glutamine synthetase synthesis in Escherichia coli.
Transcription of the Ntr regulon is controlled by the two-component system consisting of the response regulator NRI (NtrC) and the kinase/phosphatase NRII (NtrB), which both phosphorylates and dephosphorylates NRI. Even though in vitro transcription from nitrogen-regulated promoters requires phosphorylated NRI, NRII-independent activation of NRI also occurs in vivo. We show here that this activation likely involves acetyl phosphate; it is eliminated by mutations that reduce synthesis of acetyl phosphate and is elevated by a mutation expected to cause accumulation of acetyl phosphate. With purified components, we investigated the mechanism by which acetyl phosphate stimulates glutamine synthetase synthesis. Acetyl phosphate, carbamyl phosphate, and phosphoramidate but not ATP or phosphoenolpyruvate acted as substrates for the autophosphorylation of NRI in vitro. Phosphorylated NRI produced by this mechanism exhibited the properties associated with NRI phosphorylated by NRII, including the activated ATPase activity of the central domain of NRI and the ability to activate transcription from the nitrogen-regulated glutamine synthetase glnAp2 promoter.
Adenosine Triphosphatases↗
The polyomavirus enhancer activates chromatin accessibility on integration into the HPRT gene.
Recent studies suggest that enhancers may increase the accessibility of chromatin to transcription factors. To test the effects of a viral enhancer on chromatin accessibility, we have inserted minigenes with or without the polyomavirus enhancer into the third exon of the hypoxanthine phosphoribosyltransferase (HPRT) gene by homologous recombination and have prepared high-resolution maps of gene accessibility by using a novel polymerase chain reaction assay for DNase I sensitivity. In its native state, we find that the HPRT gene has low sensitivity to DNase I in fibrosarcoma cells. Insertion of the polyomavirus enhancer and neo reporter gene into exon 3 confers altered HPRT DNase I sensitivity for several kilobases on either side of the enhancer. The changes in DNase I sensitivity peak near the enhancer and decline with distance from the enhancer. The increase in HPRT DNase I sensitivity persisted when the tk promoter was deleted from the inserted construct but disappeared when the enhancer was deleted. These experiments identify the polyomavirus enhancer as a cis-acting initiator of chromatin accessibility.
Base Sequence↗
[Studies of distribution of subtypes of transferrin, group-specific component, alpha 1-antitrypsin in gastric cancer patients from Shanghai area].
The genetic polymorphism of transferrin (Tf) and alpha 1-Antitrypsin (alpha 1-AT) in 202 gastric cancer patients and 202 controls in Shanghai Hans were analyzed by isoelectric focusing. In transferrin, the phenotype frequency of C1C1 and gene frequencies of c1 and c2 were 0.3713, 0.5718 and 0.4109 respectively in gastric cancer patients, and 0.5149, 0.6782 and 0.2970 separately in controls. The frequencies of the c1c1 phenotype and the C1 gene increased significantly (p < 0.01) among the controls, while the frequency of the C2 gene greatly increased (p < 0.01) among the patients. The frequencies of the C2C2 in gastric cancer patients and controls were 0.2228 and 0.1436 respectively, showing a significant difference between them (p < 0.05). The genetic polymorphisms of group-specific component (Gc) in 200 gastric cancer patients and 200 controls in Shanghai Hans were studied with isoelectric focusing followed by immunofixation. The Gc1F1F phenotype frequency and 1Fgene frequency were 0.22 and 0.4375 in gastric cancer patients, and 0.14 and 0.3600 in controls, respectively. The frequencies of the Gc1F1F phenotype and the 1F gene were significantly increased (p < 0.05) among the patients. In alpha 1-Antitrypsin, there was no significant difference in phenotype frequencies and gene frequencies between the patients and controls. The data reported here indicate that the gastric cancer is associated positively with TfC2 and Gc1F, and negatively with TfC1. These facts support the notion that cancerogenesis is a multi-step process controlled by multifactorial inheritance.
Adult↗
[Study on radionuclide migrating along the channel].
The study of impedance line along channel had been performed with the radionuclide tracing method in 15 healthy human being and 4 guinea pigs. These images of tracer migrating routes approximately corresponded with classical courses of channel. The study proved that these line-shaped tracer migration were not by the way of lymphatic and blood vessels as well as nerves. This image of radionuclide migrating along channel may used as the guide for the observation of micro-autoradiography. In this study, satisfactory migrating image along the channel was also obtained by 131I instead of 99mTC. So a new way was opened up for both macro- and micro-autoradiographic study.
Adult↗
Anaerobic vertebral osteomyelitis.
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Aged↗
[Propagation methods for nutmeg seeds].
The test was conducted on the interrelated factors of germination of Nutmeg seeds. The result indicated that germination occurred fast and exuberantly (up to 88.8%) when the fresh and plump seeds (collected in summer or early autumn) were shown and expedited in clean sand in the complete shade during May-August after being treated with wet sand for 96 hours.
Medicine, Chinese Traditional↗
[Gene diagnosis of hemophilia A by PCR].
DNA fragments containing restriction enzyme Bcl I or XbaI polymorphic sites within the gene of coagulation factor VIII were amplified, respectively. Carrier detection and prenatal diagnosis of hemophilia A were performed by analysis of the polymorphisms of the amplified DNA. This is a simple, fast and sensitive technique, especially for prenatal diagnosis with very small amounts of chorionic villi or amniocytes. Four families with hemophilia A were analyzed, and 3 cases at high risk for hemophilia A were diagnosed prenatally.
Female↗
A preliminary study of radioimmunoimaging by 131I-COC183B2 monoclonal antibody in patients with epithelial ovarian cancer.
Monoclonal antibody 131I-COC183B2, developed in our laboratory and proved to fit for human treatment was injected intraperitoneally or subcutaneously in 13 patients. In 8 cases with i.p. injection the disease corresponded with the image, i.e. 3 primary ovarian epithelial cancers showed positive images, 1 ovarian Krukenberg tumor was negative and the other 4 negative images included 1 uterine myoma and 3 ovarian teratomas. In the subcutaneous injection group, 4 cases had ovarian carcinoma, surgery and chemotherapy. Two negative images corresponded with the clinical status-in good health, another negative case had metastatic left supraclavicular lymph node due to ovarian mucinous adenocarcinoma. The last negative image in this group was a case of benign ovarian teratoma which was proved after surgery. The 1 positive case was waiting to be proved by a scheduled third operation. The computer scintigram calculation of T/NT was 5.35 to 13.7. The results suggest that this monoclonal antibody can be used for radioimmunoimaging for the localization of ovarian carcinoma, which is not only helpful for clinical staging and differential diagnosis but is also a good follow-up method.
Antibodies, Monoclonal↗
[A report of surveillance on acute diarrhoeal diseases in Wuwei Prefecture from 1987 to 1988].
Surveillance on acute diarrhoeal diseases in Jinta County, Wuwei City for two successive years from January 1987 to December 1988 showed that the annual average incidence of diarrhoeal diseases was 0.079-0.124. The total detection rate of the etiologic agent was 58.95%. Bacterial infection was predominant. Ten species of pathogenic bacteria were detected, of which shigella remained the prevalent bacteria among which flexneri appeared as the predominant species after a decline for several years since early 1980s. The percentage of rotavirus was rather low. Diarrhoea was related to multiple factors. Children under 5 years old should be regarded as the target population for the prevention. Early detection of carriers has great significance in the prevention and control of diarrhoea.
Adolescent↗
Harmonic generations in an optical Fibonacci superlattice.
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Journal Article↗
[The natural variance of transient myocardial ischemia in coronary artery patients].
Sixty patients of CAD were studied with 24 and 48 hours ambulatory electrocardiogram monitoring. The day-to-day natural variances of transient myocardial ischemia in this group were analysed. The ranges of variation of myocardial ischemia based on a 95% confidence interval were confirmed. The results showed that the day-to-day variances of ischemia between the different days were: (1) 43% in number of ischemia episodes, (2) 76% in duration, (3) 53% in integration, and (4) 48% in maximal degree of ST depression.
Analysis of Variance↗
Generation and characterization of human monoclonal antibody HMD4 against ovarian carcinoma and the study of radioimmunoimaging in nude mice.
Lymphocytes from regional lymph nodes of patients with ovarian carcinoma were immortalized by fusing them with a nonsecreting cell line of murine myeloma (Sp2/0-Ag14). By early cloning and recloning a hybrid cell line, named HMD4, was established. It has secreted human IgG for more than 15 months stably. Chromosome analysis corresponded with the characterization of human-mouse hybridoma. Large quantities of ascites were obtained after hybrid cells injection into the primed nude mice. Human IgG of light chain was detected and purified from the ascites. Twenty-six of 43 (60.5%) epithelial ovarian cancers were positively stained with HMD4 by ABC immunoperoxidase methods while nonepithelial ovarian cancers and almost all benign tumors and normal tissues were negative. The molecular weight of the antigen recognized by HMD4 was 55KDa determined by Western blotting. 131I labeled HMD4 was administered intraperitoneally to nude mice bearing human ovarian epithelial adenocarcinoma; 131I labeled normal human IgG and normal murine IgG were used as controls. Measurements of T/NT and T/B ratios of 131I-HMD4 were done. Radioimaging showed HMD4 clearly localized on tumor regions at 48 and 72 hours and the biodistribution and metabolism of the labeled HMD4 corresponded with the images. The above results indicate that HMD4 was specific to ovarian carcinoma, a hopeful clue for clinical applications.
Animals↗
A human monoclonal antibody HMD4 against ovarian carcinoma associated antigen.
Lymphocytes from regional lymph nodes of patients with ovarian carcinoma were immortalized by fusing them with a nonsecreting cell line of murine myeloma (Sp2/0-Ag14). The fusion rate was 0-87.5%. By early cloning and recloning, a hybrid cell line, named HMD4, was established. It has stably secreted human IgG for more than 15 months. Chromosome analysis showed the characteristics of human-mouse hybridoma. The cells of HMD4 were injected into the abdominal cavities of nude mice and 2-3 weeks later large quantities of ascites were obtained. Human IgG of lambda light chain was detected and purified from the ascites. The specificity of HMD4 human McAb was tested by ABC or PAP immunoperoxidase stainings of paraffin-embedded tissue sections, cryostat sections, cell smears of various tissues and different cancer cell lines. 60.5% (26/43) of epithelial ovarian cancers was positive, while nonepithelial ovarian cancers, most cancers from other organs and almost all nonmalignant and normal tissues were negative. The molecular weight of the antigen recognized by HMD4 was 55 KDa determined by Western blotting. The problems of maintaining the IgG secreting function of human-mouse hybridoma and its screening were also discussed.
Animals↗
[Electron spin resonance (ESR) study on hair of rats with diabetic cataract].
The hair taken from 40 rats with diabetic cataract and 20 normal controls was tested by using ESR. It was found that the 'g factor' of the hair of the rats with diabetic cataract is higher than that in normal controls. The intensity of ESR signals of the hair taken from rats with diabetic cataract is three times higher than that of ESR signals of the hair from the normal controls. The results have suggested a good reappearance and a remarkable increase in number of the free radicals and other particles of paramagnetic substances during the course of the development of the rats' diabetic cataract. The study provides new scientific data for the theory of free radicals damaging to the crystal in the process of the formation of diabetic cataract.
Animals↗