Search PubMed⌕ Search

Biomedical subjects

J Dong

Publications and source records attributed to J Dong.

At least 199 records · Page 11Linked to original sources
PubMed1995

[Susceptibility study on urogenital Chlamydia trachomatis to 19 kinds of antibiotics].

We detected the minimal inhibitory concentrations (MIC) and minimal bacteriocidal concentrations (MBC) of 19 kinds of antibiotics against urogenital chlamydia trachomatis (CT) from sexually transmitted disease (STD) patients. The results were as follows: (1) The mean MICs of tetracycline, doxycycline, minocycline, erythromycin, josamycin, medimycin, lomexacin and ofloxacin were lower than 0.08 microgram/ml. Clindamycin was lightly inhibitant to CT. Steptomycin, cephaloradine, chloramiphonic, metronidazole, ciprofloxacin, sulfamethaxazole and trimethoprim showed no activitis to urogenital CT. (2) The values of the MICs and MBCs of the standard strains were among those of the isolated ones. Another the differences in drug susceptibility of different serovars were observed. (3) The MIC detected method is also discussed.

Cervix Uteri↗
PubMed1995

[Amplification and overexpression of c-erbB2 in human breast cancer].

Quantitative DNA dot blot hybridization and immunohistochemical method were employed to detect amplification and overexpression of proto-oncogene c-erbB2 in 101 paraffin-embedded breast cancers. The results showed that c-erbB2 was amplified and overexpressed in 34.7% and 23.8% of examined cases respectively. The overexpression of c-erbB2 was correlated with, but not always paralled to the gene amplification. The moderate to high-level overexpression of c-erbB2 detected by immunohistochemistry was significantly associated with the size of the tumour and the number of lymph nodes involved. No differences were found in the alteratio of c-erbB2 gene and its protein expression between primary and metastatic breast cancers indicating that the genotypic and phenotypic changes of c-erbB2 occured prior to and maintained in the process of metastasis of breast cancer.

Breast Neoplasms↗
PubMed1995

Amygdalo-entorhinal relations and their reflection in the hippocampal formation: generation of sharp sleep potentials.

While the anatomical relations between the amygdala, parahippocampal cortices, and hippocampus have been studied extensively, little is known about how they interact. To address this issue, we studied the timing of entorhinal (ENT), subicular, and basolateral amygdaloid (BL) discharges with respect to previously unknown population events, hereafter termed sharp potentials (SPs), that appear in the ENT cortex of cats during EEG-synchronized states. SPs occurred in two forms. Simple SPs were monophasic potentials, negative in deep ENT layers and positive in layer I. Complex SPs appeared as simple SPs interrupted by a brief potential of opposite polarity. Simple SPs had no hippocampal correlate whereas complex SPs were followed by large potentials that could be recorded at several levels of the hippocampal loop under barbiturate anesthesia, but not beyond the dentate gyrus in natural sleep. In agreement with this, layer II ENT neurons and most subicular cells fired only in relation to complex SPs under anesthesia. Layer II ENT neurons fired in phase with SPs whereas subicular neurons fired 20-40 msec later. In contrast, BL cells, layers IV-VI and layer III ENT neurons fired sequentially in relation to SPs with BL cells discharging as early as 40 msec before SPs. Finally, amygdala lesions abolished ENT SPs. These results suggest that the BL complex plays an essential role in the generation of population events that are transmitted to the ENT cortex. This is the first demonstration that spontaneous events occurring in the amygdala are reflected in the activity of related cortices. In turn, layer II ENT neurons gate the transfer of incoming inputs to the hippocampus. These findings shed light on the elaboration of normal and pathological activities in the amygdalo-hippocampal network.

Action Potentials↗
PubMed1995

Difference between the resistance mechanisms of aclacinomycin- and adriamycin-resistant P388 cell lines.

Aclacinomycin (ACR) is an anthracycline anticancer drug that shows marked effects in Adriamycin (ADM)-resistant tumors. ADM, however, is not effective against ACR-resistant tumor cells. When tumor cells acquire resistance to ACR, though the resistance is not easily acquired, they show strong cross-resistance to ADM. To study the mechanism underlying these phenomena, we studied the resistance mechanism of ACR- and ADM-resistant P388 leukemia cells. The P388/ACR cells showed 4.9- and 100-fold resistance to ACR and ADM, respectively, whereas the P388/ADM cells showed respectively 2.0- and 270-fold resistance. Both P388/ACR and P388/ADM cells expressed large amounts of P-glycoprotein, and the amount was 3-fold higher in the P388/ACR than in the P388/ADM cells. As a result, the accumulation of vincristine and ADM were greatly reduced in P388/ACR and P388/ADM cells, as compared with the parental P388 cells. The accumulation of ACR, however, was moderately reduced in both the resistant cell lines. ACR accumulation in P388/ACR and P388/ADM cells was reduced to respectively 37 and 64% of the level in P388 cells. The amount and the activity of topoisomerase II were comparable in P388 and P388/ACR cells, but they were reduced in P388/ADM cells. Consequently, the formation of protein (topoisomerase II)-DNA cross-links induced by a topoisomerase II inhibitor was more prominent in the P388 and P388/ACR nuclei than in the P388/ADM nuclei. Notably, ACR could reduce the protein-DNA cross-links equally in the nuclei of P388, P388/ACR, and P388/ADM cells.(ABSTRACT TRUNCATED AT 250 WORDS)

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

[Effects of three kinds of decoction on histopathology of gastric mucosa, gastric pH and the content of bile acid in experimental chronic gastritis in rats].

Experimental chronic gastritis (ECG) models were established in rats by inserting a spring into pyloric canal as well as feeding sodium deoxycholate. An experiment was undertaken to observe the therapeutic effects of three formulas of traditional Chinese medicine "Shipitong", "Ganpingyangwei" and "Weile". The experimental results show that all of the three decoctions can reduce gastric pH and bile acid of the ECG rats and make gastric mucosal histomorphology of these rats change markedly.

Animals↗
PubMed1995

[Treating steroids dependent asthmatic patients with high dose beclomethasone dipropionate aerosol].

In order to provide a more effective alternative therapy for the steroid dependent asthmatic (SDA) patients, 23 SDA patients replaced their oral steroids with high dose beclomethasone dipropionate (1500 micrograms/d) inhalation were investigated. The changes of clinical features, pulmonary function and the Synacthen test were recorded. The results showed that about 82% of the patients replaced their oral steroids completely or partially with the inhalation therapy, the clinical features were improved in 13% of the patients and the failure rate was only 4.4%, the results also revealed that, after replacement, the pulmonary function of the patients were improved (P < 0.05); according to the results of Synacthen test, after alternative therapy for 3-6 months, the damaged reserve power and secretive ability of adrenal cortex of the patients were also partially improved (P < 0.01).

Administration, Inhalation↗
PubMed1995

Quantitative detection of amplification of proto-oncogenes in breast cancer.

In the present study, dot-blot hybridization, serial dilution analysis and densitometric scanning were used to detect amplification of proto-oncogenes including c-erbB2, c-myc, int-2 and c-Ha-ras in 101 paraffin-embedded breast cancers. Expression of c-erbB2 was also examined by immunohistochemistry. Amplification of c-erbB2, c-myc and int-2 genes was found in 34.7%, 17.8% and 11.9% of breast cancers respectively. However amplification of c-Ha-ras was not detected in all cases. In 11.9% of cases co-amplification of two or more oncogenes was observed. Positive immunostaining of c-erbB2 was seen in 23.8% of the cases and it was significantly associated, but not always corresponding to the amplification of the gene. There was no difference between primary and metastatic breast cancer in the alterations of proto-oncogenes examined in this study, which suggested that the amplification and overexpression of these proto-oncogenes occurred prior to and maintained in the process of metastasis of breast cancer. Statistical analysis showed that high-scale of immunopositive staining of c-erbB2 and high-fold co-amplification of proto-oncogenes were significantly correlated with large size of the tumour and the number of involved lymph nodes. Our results indicate that the alterations of multiple oncogenes are involved in the development of breast cancer and some of them may have prognostic importance for breast cancer patients.

Breast Neoplasms↗
PubMed1995

Transseptal methods for percutaneous balloon valvoplasty simultaneously with radiofrequency catheter ablation.

Percutaneous balloon mitral valvoplasty (PBMV) and radiofrequency catheter ablation (RFCA) have been used in the treatment of mitral stenosis (MS) and supraventricular tachycardia. The techniques of PBMV and RFCA yield better results with the development of interventional cardiology, but there is no report about PBMV performed simultaneously with RFCA in the same patient. Seven patients with mitral stenosis and Wollf-Parkinson-White (W-P-W) Syndrome were successfully treated with PBMV and RFCA by transseptal methods. LA, LAP, mPG and mPA were decreased from 43.4 +/- 4.6mm, 21.8 +/- 6.8mmHg, 21 +/- 7.7mmHg and 45.7 +/- 16.5mmHg to 39.2 +/- 3.7mm (P < 0.05), 12.7 +/- 4.5mmHg, 12 +/- 3.7mmHg and 32.3 +/- 9mmHg (P < 0.01). MVA was increased from 0.96 +/- 0.33cm2 to 1.7 +/- 0.80cm2 (P < 0.01). delta wave disappeared in 12-lead surface EKG and SVT could not be induced in electrophysiological study after the treatment. The overall time of the procedure for this series was 93 +/- 34 minutes and fluoroscopy time was 23 +/- 7 minutes on the average. Radiofrequency energy applications were 3 +/- 2 times each procedure. PBMV and RFCA are safe and highly effective in the treatment of MS and W-P-W syndrome. The results in the present study proved the feasibility of the combined use of PBMV and RFCA. We prefer a first choice of PBMV and then RFCA in order to avoid aggravation of the hemodynamics due to mitral stenosis. The results also showed that of overall procedure and fluoroscopy only took a short time for this series. We suggest that it could be used as a routine method for the treatment of mitral stenosis complicated by W-P-W syndrome.

Adult↗
PubMed1995

[Evaluation and its clinical significance of anti-platelet granule membrane protein-140 autoantibodies and anticalmodulin antibody in patients with severe pregnancy-induced hypertension].

OBJECTIVE: To study the effect of immune function of platelet on the pathogenesis of severe pregnancy-induced hypertension. METHODS: 46 plasma samples from patients with severe pregnancy-induced hypertension (PIH) were evaluated for autoantibodies directed against granule membrane protein-140 (GMP-140) and anticalmodulin antibody (A-CaM) using ELISA methods. RESULTS: Autoantibodies to GMP-140 existed in 13 patients with severe PIH (28.6%), after SDS-page of purified GMP-140 immunoblotting showed that 1 out of 8 sera from patients presented a staining band with M.W. of 140 kd. 29 plasma samples were found autoantibodies to GMP-140, GP IIb/IIIa and GP Ib/IX, simultaneously. It was shown that antiGMP-140 activities coexisted with anti-GP IIb/IIIa and/or anti-GPIb/Ix in 29 cases (81.8%). The elevated A-CaM was observed in the patients with severe PIH reaching to 20.02 +/- 3.74U/L, that was much higher than those from the normal (7.53 +/- 2.57U/L, P < 0.05). CONCLUSION: Our study provided the evidence for autoantibodies to GMP-140 and A-CaM in some of patients with severe PIH, it has certain importance for further study on the pathogenesis of severe PIH.

Autoantibodies↗
PubMed1995

[Epoxide acrylate maleic resin and hydroxyapatite composite material as a bone graft substitute in surgical correction of orbital reconstruction].

This paper illustrates the results of surgical correction in 11 cases with orbital deformities such as periorbital deficiency after orbitotomy for retinoblastoma and orbital malposition after facial trauma. EH composite material, mixture of hydroxyapatite and epoxide acrylate maleic resin in constant proportion, was used as a good bone graft substitute in all 11 cases. This material was easier to be molded during surgery, safe to human body, had no toxic effects, no irritation and no implant-related complications. The early results obtained in these patients are encouraging.

Adolescent↗
PubMed1994

Differential suppression of mammary and prostate cancer metastasis by human chromosomes 17 and 11.

Metastasis suppressor activities have previously been mapped to human chromosomes 17 and 11. Decreased expression of the metastasis suppressor gene NM23, which is located on chromosome 17, has been correlated with increased metastatic potential in mammary cancers. A region on human chromosome 11, from 11p11.2-p13, has been shown to suppress metastasis in rat prostatic carcinoma cells. In both cases the metastasis suppressor activity had no effect on tumorigenicity or tumor growth rate, demonstrating that the encoded activities are distinct from effects of tumor suppression. To determine whether these human chromosomes encode general or tissue-specific metastasis suppressor activities, a truncated human chromosome 17 (i.e., pter-q23) and a full-length human chromosome 11 were separately transferred into highly metastatic rat mammary and prostate cancer cell lines and tested for their ability to suppress spontaneous metastasis in vivo. These studies demonstrated that when the pter-q23 region of human chromosome 17 is retained by the microcell hybrids, the metastatic ability of both mammary and prostatic cancer cells is suppressed. In contrast, when the pter-q14 region of human chromosome 11 is retained, only the metastatic ability of prostatic cancer cells is suppressed. Additional studies demonstrated that the metastasis suppressor activity encoded by the chromosome 17 pter-q23 region is p53-independent and not due to enhanced expression of NM23 protein.

Animals↗
PubMed1994

Transport of cyclosporin A across the brain capillary endothelial cell monolayer by P-glycoprotein.

P-glycoprotein, a multidrug transporter protein, exists in the brain capillary endothelium. To study the function of P-glycoprotein in brain capillary endothelium as a barrier against cyclosporin A, we examined the interaction of cyclosporin A with P-glycoprotein expressed in cultured brain capillary endothelial cells (MBEC4). P-glycoprotein of MBEC4 specifically bound [125I]iodoaryl azidoprazosin, and the binding was inhibited by cyclosporin A and vincristine. Intracellular accumulation of cyclosporin A in MBEC4 was about one-third the amount accumulated in mouse aortic endothelial cells (MAEC3), a cell line that did not express P-glycoprotein. The reduced accumulation of cyclosporin A in MBEC4 was increased by verapamil, a competitive inhibitor of transport function of P-glycoprotein. Cyclosporin A was preferentially transported from basal to apical side when the cell monolayer of MBEC4 was formed; however this transendothelial transport was not observed across cell monolayer of MAEC3. Verapamil inhibited the transendothelial transport of cyclosporin A across the MBEC4 monolayer. Thus P-glycoprotein in brain capillary endothelium could transport cyclosporin A across the endothelium from the basal to the apical side. These observations suggest that P-glycoprotein is involved in the complex function of the blood-brain barrier as a secretory detoxifying transporter of cyclosporin A.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Structure of the mouse growth/differentiation factor 9 gene.

Using a mouse GDF-9 cDNA as a probe, over 20 kb of sequence encompassing the GDF-9 gene was isolated from a mouse 129SvEv genomic library. Sequence analysis of the exons, exon-intron boundaries, and 5'- and 3'-non-translated regions was used to establish the structure of the mouse GDF-9 gene. The GDF-9 gene is encoded by two exons separated by a 2.9 kb intron. Multiple putative transcription start sites are detected between 31 and 57 bp upstream of the start site of translation and a putative polyadenylation signal lies 342 bp 3' of the end of translation. Knowledge of the GDF-9 gene structure will enable us to further understand the role of GDF-9 in ovarian physiology and development.

Amino Acid Sequence↗
PubMed1994

The proregion of cathepsin L is required for proper folding, stability, and ER exit.

To investigate the role of the proregion in the biosynthesis and trafficking of mouse cathepsin L, cathepsin L cDNAs encoding proteins with altered proregions were constructed and their expression in COS cells was examined. As in transformed cells, normal mouse cathepsin L was secreted by COS cells. In contrast, two altered proregion cathepsin L proteins, one in which the proregion was deleted and a second in which the proregion was replaced with that of a homologous protein (aleurain), were retained within the cell and degraded over a period of 2-6 h. Immunofluorescence localization and the lack of effect of NH4Cl and brefeldin A on the turnover of the altered cathepsin L proteins indicated that their degradation occurred in the endoplasmic reticulum (ER). By using brefeldin A to induce colocalization of the UDPGlcNAc: lysosomal enzyme N-acetylglucosamine-1-phosphotransferase with the cathepsin L proteins in the ER, it was shown that the altered proteins were not susceptible to mannose phosphorylation as they exist in the ER. Trypsin sensitivity assays indicated that altered proregion proteins synthesized in COS cells or in vitro are misfolded. Taken together, these results indicate that the proregion plays an essential role in proper folding of cathepsin L. ER retention, decreased stability, and lack of mannose phosphorylation of the altered proteins are most likely secondary effects resulting from improper folding.

3T3 Cells↗
PubMed1994

Paternally inherited chloroplast polymorphism in Pinus: estimation of diversity and population subdivision, and tests of disequilibrium with a maternally inherited mitochondrial polymorphism.

We have surveyed a chloroplast DNA restriction fragment length polymorphism in 745 individuals, distributed rangewide in eight allopatric natural populations of jack pine (Pinus banksiana Lamb.) and eight allopatric natural populations of lodgepole pine (Pinus contorta Dougl.). The polymorphic region of the chloroplast genome is located near duplicated psbA genes. Fourteen length variants were found in the survey, and these variants distinguished the two species qualitatively. Variant diversities were high in both species (hes = 0.43 in jack pine; hes = 0.44 in lodgepole pine). Population subdivision was weak within and among lodgepole pine subspecies and in jack pine (i.e., theta values were less than 0.05). This weak subdivision is compatible with theoretical predictions for paternally inherited markers in wind-pollinated outcrossers, as well as for polymorphisms with high length mutation rates. If these populations are at a drift-migration equilibrium, the chloroplast DNA restriction fragment data and previous mitochondrial frequency data from the same individuals are consistent with gene flow that is differential through seeds and pollen. The new data have permitted the first empirical tests of disequilibrium between maternally and paternally inherited factors. As expected, these tests failed to detect convincing evidence of nonrandom association between chloroplast and mitochondrial variants.

Chloroplasts↗