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Biomedical subjects

X Kong

Publications and source records attributed to X Kong.

At least 55 records · Page 3Linked to original sources
PubMed2000

Injury detection for central nervous system via EEG with higher order crossing-based methods.

Higher order crossing (HOC) is a powerful tool for time series analysis. Two HOC-based EEG analysis methods are developed for brain injury detection and quantification. The first method explores EEG spectrum characteristics via an estimate of the dominant frequency of a pre-processed EEG signal. The second method is based on the norm of the AHOC, an HOC obtained from the alpha-filter prefiltered EEG signal. Both methods are shown to be effective in detecting hypoxic/asphyxic injuries as well as assessing the severity of the injury.

Animals↗
PubMed2000

[Influence of mannitol on early enlargement of hematoma in hypertensive cerebral hemorrhage].

OBJECTIVE: To probe into the influence of mannitol on early enlargement of hematoma in hypertensive cerebral hemorrhage, and to discuss how to use mannitol correctly. METHODS: 93 patients with hypertensive supratentorial non-thalamic cerebral hemorrhage and light intracranial hypertension, and with less than 30 ml of hematoma volume determined by cranial CT within 6 h after the onset were randomly divided into a group in which mannitol was used (n = 46) or a group in which mannitol was not used (n = 47) within 24 h. Cranial CT was redone at 48 h. If the volume of hematoma increased by 33%, it was named early enlargement of hematoma. The influence of using mannitol within 24 h after the onset on early enlargement of hematoma was analyzed. RESULTS: 14(14/46) patients in the group in which mannitol was used within 24 h after the onset had early enlargement of hematoma, yet 4(4/47) patients in the group without mannitol had hematoma enlargement. There was significant difference between them (P < 0.01). No significant difference was seen between the integral of nerve function defect in the two groups when CT was done at the first time (P > 0.05). When CT was redone, the integral of nerve function defect in the group with mannitol used within 24 h was markedly higher than that in the group without mannitol (P < 0.05). 5(5/46) patients died in the former group and 1(1/47) in the latter. CONCLUSION: Improper use of mannitol within 24 h after the onset may increase the incidence of early enlargement of hematoma in patients with hypertensive cerebral hemorrhage, and exacerbate the patient's condition. For patients with hypertensive cerebral hemorrhage with light intracranial hypertension, especialy those within 24 h after the onset, mannitol should not be used blindly, in case that it enlarges the hematoma and exacerbates patient's condition.

Cerebral Hemorrhage↗
PubMed2000

[Study on typing of respiratory syncytial viruses].

OBJECTIVE: To determine the epidemiologic patterns of subgroups A and B and genotypes of respiratory syncytial viruses (RSV) during two uncontinuously epidemic years from 1990 to 1991 and 1997 to 1998 in Beijing. METHODS: Nasopharyngeal secretion (NPS) samples of RSV positive or BSV isolates tested by indirect immunofluorescent (IIF) assay were classified into subgroups A and B. Also, isolates of RSV were divided into at least six different lineages, designated NPl-6, by restriction mapping of the N gene. NP l, 3 and 6 were given by subgroup B isolates, while NP2, 4 and 5 were given by subgroup A isolates. Strains of subgroup A were further subdivided into six lineages SHL 1-6 on the basis of the SH gene sequence. SH lineages were closely related to each other and to NP 1-6. Strains of SHL 1,3, and 4 were closely related and belonged to NP2, SHL 2 and 6 to NP4 and SHL5 to NP5. RESULTS: Of 145 RSV NPS samples from the winter 1997 to the spring 1998, 83(57.2%) were subgroup B strains, 62(42.8%) were sub-group A strains, the rate of occurrence of subgroup A to B strains was about 1:1.3. Two of 10 isolates of 1997-1998 offered by viral department of research institute of Pediatrics were subgroup A strains, whereas 8 were subgroup B strains, the rate of occurrence of subgroup A to B strains was 1:4. Eight subgroup A strains of 10 isolates from the 1990-1991 epidemic were dominant, the proportion of subgroup A to B strains was 4:1. of 10 BSV isolates in 1997-1998, all 2 subgroups A strains gave N gene fragment restriction pattern NP4, and fell into SH lineage SHL2, whereas 8 subgroup B strains all belonged to NP3. All 8 subgroup A isolates from the 1990-1991 epidemic gave pattern NP4, and fell into SHL2, while 2 subgroups B strains all belonged to NP3. The classification of subgroups A and B deduced from NP patterns was corresponded to the definition of these subgroups by monoclonal antibodies. CONCLUSIONS: These observations confirmed that subgroups A and B or multiple lineages of BSV co-circulated in Beijing, but different genomic types predominated each year. Moreover, very similar viruses were isolated up to more than 5 years ago, indicating that despite apparent diversity of the subgroup A strains, the separate lineages might be relatively stable.

Child↗
PubMed2000

[Expression of VEGF and tumor angiogenesis in bladder cancer].

OBJECTIVE: To evaluate expression of vascular endothelial growth factor (VEGF) and its relation to angiogenesis in bladder cancer. METHODS: The expression of VEGF by immunohistochemical staining was examined in 68 cases of primary transitional carcinoma (TCC) and 7 subjects with normal urothelium. Microvessel density (MVD) in 40 cases of invasive bladder cancer was determined by Factor VIII immunohistochemical staining. RESULTS: The expression of VEGF was negative or low level in all normal bladder tissue but high in bladder cancer. VEGF and MVD were closely related to tumor cell nuclear grade and clinical stage. The average MVD was higher in the cases with the high level expression of VEGF, than in those with the low level expression of VEGF. CONCLUSIONS: This study indicates that VEGF is positively correlated with the occurrence and progression of bladder cancer. VEGF is one of the primary angiogenic factors for bladder cancer, and is able to induce tumor angiogenesis and accelerate tumor growth. Quantification of VEGF may provide a valuable marker for a poorer prognosis of patients.

Adult↗
PubMed2000

[Determination of the composition distribution of polymer blend films by using microscopic FTIR].

In this paper, PS/PC blend film (about 120 microns thick) and PS/PMMA (about 90 microns thick) blend film were prepared by evaporation the solvent very slowly from polymer blend solution. Different FTIR methods were used to determine the composition distribution along the vertical direction of the films. PS/PC film was firstly sectioned by ultramicrotomy, then the vertical section was measured to determine the composition of every 16 microns width unit from the surface-side to the bottom-side by Microscopic transmission-FTIR. The results showed that the concentration of PS was significantly greater in the vicinity of the surface of the film than that in the bulk, i.e., the component of PS enriched to the surface. Focusing the reflecting infrared light on different layer of the film, we can detect the composition of the different depth region in the PS/PMMA blend film. As the result, PMMA aggregated to the bottom of the film. It was considered that this effect was related to the different affinity and wetting prosperities of the blend component to the substrate or air.

English Abstract↗
PubMed1999

Preliminary clinical application of contrast-enhanced MR portography.

The clinical application of contrast enhanced (CE) MR was evaluated. A total of 66 CE MR portograms were obtained by performing fast imaging with steady procession (FISP) technique on a 1.5-T Siemens magnetom vision. A maximum intensity projection algorithm was also employed to include all vessels in a single image. The patency of portal venous system, the presence and extent of varices were also evaluated. The results showed that all images had diagnostic quality. Main portal vein (MPV) and its 4th-6th level intrahepatic branches were visualized in 10 normal persons serving as control. The diameter of MPV, splenic vein and superior mesenteric vein was 1.02 +/- 0.21, 0.8 +/- 0.15, 0.8 +/- 0.26 cm respectively, which were significantly lower than that in portal hypertension patients (1.38 +/- 0.27, 1.26 +/- 0.18, 1.24 +/- 0.18 cm, respectively). In 23 preoperative cases of portal hypertension, dilated portal vein and tortuous enlarged splenic vein were found in 23 cases; esophageal and coronary varices in 12 and 19 cases, respectively. In 7 postoperative re-examined cases with portal hypertension, the flow velocity and flow of MPV were decreased in all cases and esophageal varices could still be observed in 3 cases. New vessels appeared in the great curvature of stomach in 2 cases. In 20 cases of liver carcinoma, occlusion of MPV or its intrahepatic branches were showed in 14, compression and dislocation of intrahepatic portal vein were found in 6. In other 6 cases, 2 were splenic venous thrombosis and 4 were tumors in the intestine or retro-peritoneum. It is concluded that three-dimensional CE MR portography is an accurate technique for evaluating the portal venous system. It is a reliable and noninvasive technique that can provide important information for the evaluation of patients' condition before TIPSS and liver transplantation.

Contrast Media↗
PubMed1999

Quantification of injury-related EEG signal changes using distance measures.

Novel indicators based on distance measures are developed and compared to quantify changes in electroencephalogram signal resulting from hypoxic-asphyxic injury. An injury index is derived based on the measures. The Itakura distance-based index is found to have the highest correlation with the long-term outcome as measured by the neurological deficit scores.

Animals↗
PubMed1999

Adaptive estimation of latency change in evoked potentials by direct least mean p-norm time-delay estimation.

Evoked potentials (EP) have been widely used to quantify neurological system properties. Changes in EP latency may indicate impending neurological injury. Traditional EP analyses are developed under the condition that the background noise in EP analysis are Gaussian distributed. This paper proposes a latency change detection and estimation algorithm under alpha-stable noise condition, a generalization of Gaussian noise assumption. An analysis shows that the alpha-stable model fits the noises found in the impact acceleration experiment under study better than the Gaussian model. The robustness of the proposed algorithm is demonstrated through computer simulations and experimental data analysis under both Gaussian and alpha-stable noise environments.

Algorithms↗
PubMed1999

Latency change estimation for evoked potentials via frequency selective adaptive phase spectrum analyzer.

This paper addresses the problem of detecting and estimating latency changes in evoked potentials (EP's). EP's have been widely used to quantify neurological system properties. Transient and time-varying changes in latency may indicate impending neurological injury. Traditional time averaging and correlation methods for EP latency estimation are inefficient under low signal-to-noise ratio (SNR) and/or strong periodic interference conditions. This paper proposes an adaptive phase spectral time delay estimation method to detect and estimate the time-varying latency changes when both the SNR and the signal-to-interference ratio (SIR) are low. A theoretical analysis and computer simulation demonstrate that the proposed method can track the time-varying latency changes effectively and accurately when both the SNR and the SIR are as low as -5 dB. The method is also suitable for real time detection and estimation of the latency changes.

Algorithms↗
PubMed1999

Context-based lossless and near-lossless compression of EEG signals.

In this paper, we study compression techniques for electroencephalograph (EEG) signals. A variety of lossless compression techniques, including compress, gzip, bzip, shorten, and several predictive coding methods, are investigated and compared. The methods range from simple dictionary-based approaches to more sophisticated context modeling techniques. It is seen that compression ratios obtained by lossless compression are limited even with sophisticated context-based bias cancellation and activity-based conditional coding. Though lossy compression can yield significantly higher compression ratios while potentially preserving diagnostic accuracy, it is not usually employed due to legal concerns. Hence, we investigate a near-lossless compression technique that gives quantitative bounds on the errors introduced during compression. It is observed that such a technique gives significantly higher compression ratios (up to 3-bit/sample saving with less than 1% error). Compression results are reported for EEG's recorded under various clinical conditions.

Electroencephalography↗
PubMed1999

Flow cytometric analysis of BHRF1 expression prohibiting apoptosis induced by radiation.

The Epstein-Barr virus gene BHRFI has homology with proto-oncogene bcl-2, which can protect cells from apoptosis. In order to investigate the effect of BHRF1 expression on the anti-apoptotic ability of nasopharyngeal carcinoma (NPC) cells after irradiation, a high-BHRF1 expression vector was constructed and transfected into the NPC cell line CNE2. Then, the alteration of proliferation and apoptosis in the cells was tested by flow cytometry after cobalt 60 irradiation. The results showed that BHRF1 expression could increase G1 delay and decrease the cell percentage in S phase before irradiation, and reduce the apoptotic rate of CNE2 cells and increase the cell percentage in S phase after irradiation. The results suggest that BHRF1 expression is able to alter the cell cycle and protect CNE2 cells from apoptosis induced by radiation.

Apoptosis↗
PubMed1999

A contiguous 3-Mb sequence-ready map in the S3-MX region on 21q22.2 based on high- throughput nonisotopic library screenings.

Progress in complete genomic sequencing of human chromosome 21 relies on the construction of high-quality bacterial clone maps spanning large chromosomal regions. To achieve this goal, we have applied a strategy based on nonradioactive hybridizations to contig building. A contiguous sequence-ready map was constructed in the Down syndrome congenital heart disease (DS-CHD) region in 21q22.2, as a framework for large-scale genomic sequencing and positional candidate gene approach. Contig assembly was performed essentially by high throughput nonisotopic screenings of genomic libraries, prior to clone validation by (1) restriction digest fingerprinting, (2) STS analysis, (3) Southern hybridizations, and (4) FISH analysis. The contig contains a total of 50 STSs, of which 13 were newly isolated. A minimum tiling path (MTP) was subsequently defined that consists of 20 PACs, 2 BACs, and 5 cosmids covering 3 Mb between D21S3 and MX1. Gene distribution in the region includes 9 known genes (c21-LRP, WRB, SH3BGR, HMG14, PCP4, DSCAM, MX2, MX1, and TMPRSS2) and 14 new additional gene signatures consisting of cDNA selection products and ESTs. Forthcoming genomic sequence information will unravel the structural organization of potential candidate genes involved in specific features of Down syndrome pathogenesis.

Chromosome Mapping↗
PubMed1999

[The influences of interleukin-1 beta converting enzyme expression on the biologic characteristics of ovarian cancer cells].

OBJECTIVE: To investigate the effects of interleukin-1 beta converting enzyme (ICE) gene on the biologic characteristics of ovarian cancer cells. METHODS: A 1.3 Kilobase human ICE cDNA with 5' and 3' untranslated sequences was cloned into the EcoR I site of pLXSN retrovirus vector in sense orientation. After that, the recombinant plasmid pLXSN-ICE was transferred to virus-packing cell PA317 by electroporation method. And then the retrovirus containing human ICE cDNA generated by these PA317 cells were used to transfect human ovarian cancer cell lines, AO and 3AO. RESULTS: After being transfected with these retrovirus, the number of the clones obtained after G418 resistance selection is far less than that of controlled groups with plasmid pLXSN. The growth rate of these transfected cells was significantly suppressed in comparison with the parental cell line. Apoptosis was also found in these cells. After the transfection cancer cells were inoculated subcutaneously in nude mice, the tumor growth was significantly inhibited. CONCLUSION: It suggest that human ICE gene can suppress the phenotype and tumorigenicity in nude mice of ovarian cancer cell lines AO and 3AO.

Animals↗
PubMed1999

Study of activity of promoter from mouse alpha 2(I) procollagen gene.

OBJECTIVE: To clarify the segment and sequence in mouse alpha 2(I) procollagen gene which are responsible for high transcriptional activity during fibrogenesis. METHODS: This study was focused on further fractional analysis of 2 kb-length mouse alpha 2(I) procollagen gene promoter activity. Six chimeric genes were constructed in which various lengths of sequences between 2000 bp upstream of the start of transcription of the mouse alpha 2 (I) procollagen gene and 54 bp downstream of this site were fused to chloramphenicol acetyltransferase (CAT) reporter gene. These recombinant plasmids were transfected transiently to collagen-producing cells (NIH/3T3) and non-collagen-producing cells (COS7) with liposomal transfection method. The activities of putative promoters were observed and compared by means of CAT measurement in the transfected cells. RESULTS: The highest and partial cell specific CAT expression was observed in construction driven by -780 to bp fragment. The construction containing sequence deleted the proximal 500 bp from the transcription start site and part of exon I, and resulted in the lowest CAT expression. CONCLUSIONS: Some essential elements might exist in the 500 bp fraction proximal to transcription start site and part of exon I in mouse alpha 2(I) procollagen gene. The high potential promoter sequence between -780 bp from the start of transcription site and bp from this site is of great significance in our following study of searching for specific DNA-binding proteins in activated collagen-producing cells.

3T3 Cells↗
PubMed1999

Effect of integrin on procollagen synthesis by fibroblasts from scleroderma.

OBJECTIVE: To investigate the effect of integrin on fibroblasts from scleroderma in the production of procollagen. METHODS: Phosphorothioate modified antisense oligonucleotides were used to interfere with the expression of integrin alpha 5 or beta 1 subunit on fibroblasts from 10 cases of scleroderma, and then the changes of procollagen mRNA due to the decline in level of integrin were observed by using RT-PCR. RESULTS: Expression of integrin alpha 5 or beta 1 subunit was specifically inhibited by their corresponding antisense oligonucleotides. Fibroblasts with decreased expression of alpha 5 or beta 1 subunit produced lower level of procollagen alpha 1 (I), alpha 1 (III) mRNA in comparison to the control. CONCLUSION: Overproduction of procollagen may be inhibited at the level of transcription by lowering the expression of integrin alpha 5 or beta 1 subunit on fibroblasts in scleroderma.

Adult↗
PubMed1999

[The effect of combined endocrine therapy on prostate and testis].

OBJECTIVE: To study the pathological changes of the effect of combined endocrine therapy on normal prostate, benign prostatic hyperplasia, prostatic adenocarcinoma and testis. METHODS: 11 radical prostatectomy specimens, 3 core-needle biopsies of prostate and 3 testes obtained after at least 3 months of enatone-flutamide inhibition therapy were studied. Step-section was performed on radical specimens and average 16 sections per case were reviewed. PSA, PSAP and AE1/AE3 were immunostained on 14 cases of prostate cancer and a comparative study pre- and post-treatment was made. RESULTS: No residual tumor was recognized in 2 cases. Such characteristic changes were found in 9 cases as prominent acinar atrophy, decreased ratio of acini to stroma, stromal fibrosis, squamous metaplasia of carcinoma, cytoplasmic vaculation, nuclear shrinkage, and nucleolar shrinkage. No apparent change was discovered in 3 cases. Secretory epithelial atrophy and basal cell hyperplasia were the popular change in BPH and normal prostate. The expressions of both PSA and PSAP were markedly reduced in prostate carcinoma and nonneoplastic glands. Pathological downstaging of the tumor was not found statistically. Epithelial atrophy also existed in seminal vesicles and Leydig cells of the testes after hormone therapy. CONCLUSIONS: Combined endocrine therapy results in histologically distinctive changes that can be found in both nonneoplastic and neoplastic prostate tissue. However, the drugs can not eradicate prostate cancer completely. Testis atrophy is the direct action of the therapy.

Aged↗
PubMed1999

[Clinicopathologic study of 11 patients with Paget's disease of scrotum].

OBJECTIVE: To probe the relationship of clinicopathologic presentations and prognosis of Paget's disease primarily involving the scrotum. METHODS: 11 cases of scrotal Paget's disease were studied retrospectively from 1984 to 1997. PAS was stained and EMA, S-100, HMB45, CEA and CA15-3 were immunostained in all cases for the differential diagnosis from Bowen's disease and malignant melanoma. RESULTS: Six of 11 cases involved hair follicle and/or sweat glands, and 3 cases involved dermis (one had metastasis of left superficial and deep inguinal lymph nodes, and left internal iliac lymph nodes). Paget's cells were positive for PAS (11/11), EMA (11/11), CEA (6/11), CA15-3 (11/11), and negative for S-100, HMB45. Wide local excision of the lesions was performed in 10 of 11 patients both for primary disease and recurrent disease. 3 of the 10 patients underwent lymph nodes resection and metastasis was found in 1 case pathologically. One patient accepted chemotherapy and died, from respiratory insufficiency after one month. The other 10 patients were followed up for 6 to 127 months and no patient died of Paget's disease. CONCLUSIONS: Involvement of hair follicles and sweat glands by Paget's cell does not influence the prognosis.However, invasion of dermis by Paget's cells may suggest possible metastasis.

Aged↗