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Biomedical subjects

S Sun

Publications and source records attributed to S Sun.

At least 181 records · Page 10Linked to original sources
PubMed1998

[Preparation and identification of monoclonal antibodies to estrogen and progesterone receptors].

OBJECTIVE: Preparation of anti human progesterone receptor (PR) and estrogen receptor (ER) monoclonal antibodies (McAb). METHODS: Characterization of the two McAbs were detected by Western blot, immunohistochemical, immunofluorescence and fluocytometer techniques. RESULTS: (1) A specific protein belt was obtained between anti-PR McAb and the extract of cell line T47D and the same result was noticed between anti-ER McAb and extract from MCF-7 cell line by Western blot. (2) The PR and ER status of 40 and 35 human breast cancer were studied by immunohistochemistry (IHC) using the anti-PR and ER McAb. The efficacy of the McAbs prepared was just the same as that of the McAbs purchased from Zymed company. The corresponding rate of determination for ER and PR status between IHC and DCC were 85% and 91.4%, respectively. (3) The fluorescent markers were mainly localized in the cell nuclei when detected through indirect immunofluorescence techniques. (4)FCM showed that fluorescent index was larger than 1.0, and negative control F1 was less than 1.0. CONCLUSION: The anti-PR and ER McAbs prepared in this program are specific and sensitive and have the similar efficacy and quality as the Zymed PR and ER McAbs.

Animals↗
PubMed1998

[The effect of Codonopsis pilosula (Franch.) Nannf. on gastric acid, serum gastrin and plasma somatostatin concentration in dogs].

The results were obtained by oral administration of the decoction of Codonopsis pilosula in three different doses(10 g, 20 g, 40 g) to 5 dogs with Heidenhain pouch. No significant changes occurred in the acidity output of Heidenhain pouch and plasma somatostatin concentration out of the oral administration (P > 0.05). A significant increase occurred in serum gastrin concentration (P < 0.05 or P < 0.01) 150 min after a dose of 10 g, 90 min and 150 min after doses of 20 g, and 30 min, 60 min, and 150 min after doses of 40 g.

Animals↗
PubMed1998

[Studies on the synthesis and antitumor activities of howiinol A and its analogues].

Howiinol A(1), one of the active antitumor constituents from the root and stem bark of Goniothamus howii Meer. (Annonaceae) has been synthesized in nine steps from alpha-D-glucoheptonic gamma-lactone with an over all yield of 13.3%. It shows that all data of the synthetic product are identical to those of the natural howiinol A, thus the absolute configuration of natural howiinol A is further confirmed as 1. In the search for new antitumor compounds with high potency, 26 analogues have been synthesized. In pharmacological tests most of them showed antitumor activities in vitro, some of them are significant.

Animals↗
PubMed1998

[Application of improved western blot method in diagnosis of cysticercosis].

AIM: To evaluate the diagnostic value of four specific antigens from cDNA of Cysticercus cellulosae. cC1, cC2, and cP1 and cH1 (28 kDa, 18 kDa, 14 kDa and 34 kDa), mixing in equal proportions for the diagnosis of cysticercosis. METHODS: Taking the FP (fusion proteins) as antigen to make IWB (improved Western blot) analysis basing on the detection of antibody responses against FP, and making ELISA/IHA-crude antigen(CA) analysis. They were evaluated comparatively while using 107 infected sera of cysticercosis cases, 40 infected sera of clonorchiasis cases, 24 infected sera of echinococcosis cases and 34 sera of healthy persons. The FP are encoded by cDNAs of beta-galactosidase-specific antigens of Cysticercus cellulosae isolated from the cDNA library. RESULTS: 94(87.9%) sera from 107 cysticercosis cases recognized FP in IWB and could not cross-react with the sera of echinococcosis cases, clonorchiasis cases and healthy persons, the specific rates were 100%, whereas ELISA, IHA using CA were 84.1% and 74.8%, respectively and could cross-react with the sera of echinococcosis cases, the false positive rates were 2.5% and 12.5% respectively; CA-ELISA/IHA could cross-react with the sera of clonorchiasis patients, the false positive rates were 8.3% and 16.7%, respectively; and they could also cross-react with the sera of healthy persons, the false positive rates were 8.8% and 11.8%, respectively. CONCLUSION: The recombinant FP used in the immunodiagnosis of cysticercosis is specific and sensitive.

Animals↗
PubMed1998

[Immunodiagnosis of cysticercosis by simplified western blotting using recombinant fusion protein as antigen].

AIM: To provide simple and useful method for the immunodiagnosis of cysticercosis. METHODS: Fusion protein of beta-galactosidase-Cysticercus cellulosae cDNA was analysed with simplified Western blot. RESULTS: The positive rate was 93.5% when detecting 124 cases of human cysticercosis sera with four clones (cC1, cC2, cP1 and cH1) and 100% when detecting 38 cases of porcine cysticercosis sera with three clones (cC1, cC2 and cP1), being higher than those using monoclone fusion protein alone. Moreover, the fusion proteins did not react with other parasitosis sera. CONCLUSION: Simplified Western blot analysis using recombinant fusion protein as antigen was highly sensitive and specific and easy to be operated.

Animals↗
PubMed1998

[FTIR microscope study on the change of membrane protein and lipids of erythrocyte damaged by free radicals].

The FTIR Microscope and Computer Aided Analysis were used to study not only the change of secondary structure of erythrocyte membrane protein attacked by the free radicals, but also the effect of oxygen centered free radicals on the membrane lipids in this paper. The results indicate that the content of alpha-helix in the secondary structure of protein clearly changed because of the attack of the free radicals. Damaged by free radicals in 30 minutes, the protein structure could not be restored after 3 hours. The number of the P=O (vp=0), C=O and C=C in the lipids of the membrane was changed. These changes were caused by the peroxidation of the oxygen centered free radicals.

Adult↗
PubMed1998

[Synthesis of new pyrazoline fluorescent compounds and their IR spectra and fluorescence property].

The Fluorescent compounds of pyrazoline have been used in many field. According to Schellhammer theory, we designed and synthesized five new benzothiazoyl pyrazoline compounds. Their infrared spectra and fluorescent spectra of five compounds were detected. The results showed that five compounds have fluorescence, fluorescence emission wavelength is about 450nm. Effect of different substituents on the fluorescent intensity was investigated.

Fluorescent Dyes↗
PubMed1998

Coronary artery bypass grafting in patients with profound ventricular dysfunction.

Patients with severe ventricular dysfunction make up a special subset of patients who undergo coronary artery bypass procedures. For these patients, the risk associated with the bypass procedure is relatively high, but the opportunity-for-survival benefit is also greater. We studied 61 consecutive coronary artery bypass patients with preoperative ejection fractions < or = 25%, and further compared several subgroups: Group I (n = 30) ejection fractions ranged from 21% to 25%; Group II (n = 23) ejection fractions ranged from 16% to 20.9%; and Group III (n = 8) ejection fractions ranged from 10% to 15.9%. The overall mortality rate was 8% (5/61), with no deaths in Group III. The 41% (25/61) of patients who received left internal mammary artery conduits experienced a higher mortality rate, yet it did not differ significantly from that of patients who received only saphenous vein conduits. Intraaortic balloon pumps were placed in 48% (29/61) of the patients, with a progressively higher incidence in patients with poorer ventricular function (P < 0.05). Most intraaortic balloon pumps (59%) were placed intraoperatively. Two patients underwent placement of left ventricular assist devices, and 1 of these survived. Coronary artery bypass grafting in patients with poor ventricular function carries a substantial, but acceptable, mortality risk. Use of the left internal mammary artery did not improve perioperative mortality, and may have a negative impact in the early postoperative period. Intraaortic balloon pump use was most common in those patients with the worst ventricular function. Prophylactic intraaortic balloon pump use may be justified in candidates with ejection fractions < 20%.

Adult↗
PubMed1998

ECG observations in Tibetan and Han residents of Lhasa.

In order to compare the prevalence of electrocardiographic (ECG) abnormalities suggestive of right ventricular hypertrophy in native and immigrant populations residing at high altitude, a retrospective review was undertaken of data obtained from a random survey of healthy volunteers and persons with chronic mountain sickness (CMS). All persons included in the survey were ambulatory volunteers from the general community who were evaluated at the Tibet Institute of Medical Science in Lhasa, where the elevation is 3,658 meters. The 74 residents of Lhasa, whose ECGs were studied, included 30 healthy Tibetan natives of Lhasa; 24 healthy Han (Chinese) immigrants, born at or near sea level, who had migrated to high altitude as children or adults; and 20 persons with symptoms of CMS. The ECGs of all subjects were reviewed for predetermined criteria suggestive of right ventricular hypertrophy, which were found to be present in 17% of healthy Tibetan natives, 29% of healthy Han immigrants, and 50% of CMS patients. The Han subjects who had migrated as children presented evidence of right ventricular hypertrophy more commonly than did adult immigrants. The overwhelming majority (90%) of persons with CMS were Han. Thus, the frequency of ECG abnormalities consistent with right ventricular hypertrophy was similar in healthy young Tibetan and Han men, but these abnormalities were less common in Tibetan natives than in Han who had migrated to high altitude as children or in CMS patients. The prevalence of ECG evidence of right ventricular hypertrophy increased with duration of high altitude residence among Han.

Adult↗
PubMed1998

[Determination enzyme protein of CK-MB m-AST and ChE by immunological methods and survey of its applying values].

In recent decades, because considerable progress has been made due to rapid developments in basic theory and techniques in molecular biology and immunology, the determination of trace enzyme proteins is not difficult. We measured the serum concentration of Creatine kinase-MB (CK-MB) mitochondria aspartate aminotransferase (m-AST) and cholinesterase (ChE) immunologically and compared these findings with those of an assay of enzyme activity. Purification of enzyme protein and preparation of serum antibodies monoclonal antibodies established the immunological assay methods. Equipment and reagents for enzyme activity test use 7150 Biochemical Analyzer. CK-NAC AST and ChE were produced by trace kits (Australia). CK-MB and m-AST use immunological inhibition method. CK-MB m-AST ChE of protein determination used immunological turbidimetry. The normal group included 150 cases and the 1990 patient group. Results of the two methods did not significantly differ for normal controls, but were significantly different in the patient group. These results demonstrated that the two methods differ, although each may have specific clinical significance. How to evaluate these differences needs to be studied further, but immunological assay uses higher values for clinical diagnosis than enzyme activity assay.

Antibodies, Monoclonal↗
PubMed1997

CDKN2A mutation in a non-FAMMM kindred with cancers at multiple sites results in a functionally abnormal protein.

The CDKN2A gene encodes p16 (CDKN2A), a cell-cycle inhibitor protein which prevents inappropriate cell cycling and, hence, proliferation. Germ-line mutations in CDKN2A predispose to the familial atypical multiple-mole melanoma (FAMMM) syndrome but also have been seen in rare families in which only 1 or 2 individuals are affected by cutaneous malignant melanoma (CMM). We therefore sequenced exons 1alpha and 2 of CDKN2A using lymphocyte DNA isolated from index cases from 67 families with cancers at multiple sites, where the patterns of cancer did not resemble those attributable to known genes such as hMLH1, hMLH2, BRCA1, BRCA2, TP53 or other cancer susceptibility genes. We found one mutation, a mis-sense mutation resulting in a methionine to isoleucine change at codon 53 (M531) of exon 2. The individual tested had developed 2 CMMs but had no dysplastic nevi and lacked a family history of dysplastic nevi or CMM. Other family members had been diagnosed with oral cancer (2 persons), bladder cancer (1 person) and possibly gall-bladder cancer. While this mutation has been reported in Australian and North American melanoma kindreds, we did not observe it in 618 chromosomes from Scottish and Canadian controls. Functional studies revealed that the CDKN2A variant carrying the M531 change was unable to bind effectively to CDK4, showing that this mutation is of pathological significance. Our results have confirmed that CDKN2A mutations are not limited to FAMMM kindreds but also demonstrate that multi-site cancer families without melanoma are very unlikely to contain CDKN2A mutations.

Adolescent↗
PubMed1997

Mitogenicity of DNA from different organisms for murine B cells.

Recent evidence that DNA from bacteria causes polyclonal activation of mouse B cells raises the question of whether DNA from other organisms has similar properties. Extending prior studies on bacteria and insects, we show here that the capacity of DNA to stimulate B cells correlates closely with hypomethylation of DNA CpG dinucleotide motifs. Thus strong stimulation of B cells was seen with DNA from various organisms displaying little or no methylation of CpG motifs, i.e., yeast, nematodes, and molluscs in addition to bacteria and insects. For these organisms, DNA induced nearly all B cells (including small resting B cells) to up-regulate the activation marker, CD69, and caused many B cells to enter the cell cycle, indicative of polyclonal activation; this effect was not seen after selective methylation of CpG motifs (tested on yeast DNA). By contrast, no stimulation of B cells was seen with DNA from organisms whose CpG motifs are heavily methylated, i.e., various vertebrates (mammals, fish, and frogs) and plants (corn). Despite this correlation, DNA prepared from two murine cell lines exhibiting hypomethylation of CpG motifs caused little or no stimulation of B cells. Thus, the idea that the stimulatory properties of DNA correlate solely with the presence of unmethylated CpG motifs may be an oversimplification.

Animals↗
PubMed1997

Quantitative assessment of myelin basic protein-reactive T cell entry to the central nervous system by using oligonucleotide probes complementary to VDJ junctional sequences of rat TCR beta-chain.

The VDJ junctional region represents the most diverse part of the antigenic TCR. We have previously reported that of 200 sequenced TCR beta-chains of rat MBP-reactive T cells, rarely did two share sequence homology over the entire CDR3 region. In this study, we demonstrate that sequences of the TCR CDR3 region are excellent clonotypic markers for rat MBP-reactive T cell clones and oligonucleotide probes complementary to the CDR3 region of three T cell clones specifically recognized the TCR from which they were derived, but failed to recognize syngeneic T cells that express a similar TCR beta-chain or T cells that share both V beta and J beta usage. To explore this observation, we determined the ability of MBP-reactive T cell clones to enter the CNS. We were able to show that some MBP-reactive T cell clones have an augmented ability to enter the CNS and that fully-activated T cells have a higher penetrating activity than their less-activated T cell counterparts.

Amino Acid Sequence↗
PubMed1997

Metal ion catalysis during splicing of premessenger RNA.

The removal of intervening sequences from premessenger RNA is essential for the expression of most eukaryotic genes. The spliceosome ribonucleoprotein complex catalyses intron removal by two sequential phosphotransesterification reactions, but the catalytic mechanisms are unknown. It has been proposed that two divalent metal ions may mediate catalysis of both reaction steps, activating the 2'- or 3'-hydroxyl groups for nucleophilic attack and stabilizing the 3'-oxyanion leaving groups by direct coordination. Here we show that in splicing reactions with a precursor RNA containing a 3'-sulphur substitution at the 5' splice site, interaction between metal ion and leaving group is essential for catalysis of the first reaction step. This establishes that the spliceosome is a metalloenzyme and demonstrates a direct parallel with the catalytic strategy used by the self-splicing group I intron from Tetrahymena. In contrast, 3'-sulphur substitution at the 3' splice site provides no evidence for a metal ion-leaving group interaction in the second reaction step, suggesting that the two steps of splicing proceed by different catalytic mechanisms and therefore in distinct active sites.

Adenoviridae↗
PubMed1997

High-energy defibrillation increases the severity of postresuscitation myocardial dysfunction.

BACKGROUND: The fatal outcome of victims after initially successful resuscitation from cardiac arrest has been attributed both to global myocardial ischemia during the interval of cardiac arrest and to the adverse effects of reperfusion. The present study was prompted by earlier experimental observation that the magnitude of myocardial dysfunction was in part related to the energy delivered during electrical defibrillation. METHODS AND RESULTS: Ventricular fibrillation (VF) was induced in 15 Sprague-Dawley rats. Precordial compression was begun together with mechanical ventilation after 4 minutes of untreated VF and continued for 6 minutes. Spontaneous circulation was restored in each animal after external defibrillation with a single stored 2-, 10-, or 20-J countershock. Cardiac index and the rate of left ventricular pressure rise at left ventricular pressure of 40 mm Hg (dP/dt40) and fall (negative dP/dt) during the 240-minute interval after successful resuscitation were decreased, and left ventricular diastolic pressure was increased. These decreases in myocardial function were closely related to the energy of electrical defibrillation. After a 20-J shock, animals survived for only 5+/-3 hours; after a 10-J shock, animals survived for 15+/-4 hours; and after a 2-J shock, all animals survived for >24 hours. CONCLUSIONS: The severity of postresuscitation myocardial dysfunction is related, at least in part, to the magnitude of the electrical energy of the delivered shock.

Animals↗
PubMed1997

T cell stimulation in vivo by lipopolysaccharide (LPS).

Lipopolysaccharide (LPS) from gram-negative bacteria causes polyclonal activation of B cells and stimulation of macrophages and other APC. We show here that, under in vivo conditions, LPS also induces strong stimulation of T cells. As manifested by CD69 upregulation, LPS injection stimulates both CD4 and CD8(+) T cells, and, at high doses, stimulates naive (CD44(lo)) cells as well as memory (CD44(hi)) cells. However, in terms of cell division, the response of T cells after LPS injection is limited to the CD44(hi) subset of CD8(+) cells. In contrast with B cells, proliferative responses of CD44(hi) CD8(+) cells require only very low doses of LPS (10 ng). Based on studies with LPS-nonresponder and gene-knockout mice, LPS-induced proliferation of CD44(hi) CD8(+) cells appears to operate via an indirect pathway involving LPS stimulation of APC and release of type I (alpha, beta) interferon (IFN-I). Similar selective stimulation of CD44(hi) CD8(+) cells occurs in viral infections and after injection of IFN-I, implying a common mechanism. Hence, intermittent exposure to pathogens (gram-negative bacteria and viruses) could contribute to the high background proliferation of memory-phenotype CD8(+) cells found in normal animals.

Animals↗
PubMed1997

Prevalence of asymptomatic cholelithiasis and risk of acute cholecystitis after kidney transplantation.

Prophylactic cholecystectomy for asymptomatic cholelithiasis is sometimes required before transplantation. However, there is little indication in the literature that transplant recipients are at any greater risk than individuals in the general population. Between January 1990 and December 1993, 211 renal transplant recipients underwent duplex sonography. All were asymptomatic. Twenty-one had positive findings: gallstones were found in 15 patients (7.11%) and sludge was found in 6 (2.84%). Of gallstone patients, seven (3%) were men and eight (4%) were women. One gallstone patient also had diabetes mellitus. The mean age by gender of the patients with calculi was 54 years for men and 38 years for women. Thirteen of the 15 patients with calculi (87%) have remained asymptomatic. Two patients (one diabetic) developed acute cholecystitis and underwent uncomplicated laparoscopic cholecystectomy. Patients with sludge were similar in gender and age to patients with gallstones; one patient had diabetes. No sludge patients became symptomatic. The incidence and morbidity of gallstones after kidney transplantation are low. Prophylactic cholecystectomy in asymptomatic patients before transplantation is not justified.

Acute Disease↗