Biomedical subjects

Jun Chen

Publications and source records attributed to Jun Chen.

402 records · Page 23Linked to original sources

PubMedDate not supplied

Differential roles of spinal protein kinases C and a in development of primary heat and mechanical hypersensitivity induced by subcutaneous bee venom chemical injury in the rat.

It has been demonstrated that subcutaneous injection of bee venom (BV) can produce different types of pain and hypersensitivity including persistent spontaneous nociception (PSN), primary heat and mechanical hypersensitivity (hyperalgesia) and mirror-image heat (MIH) hypersensitivity in an individual animal, and the changes of spinal neurons are likely to be responsible for the production of these pain-related behaviors. In this study, we examined the roles of spinal protein kinase C (PKC) and protein kinase A (PKA) in the BV-induced different types of pain and hypersensitivity in conscious rats. We found that: (1). BV-induced primary heat hypersensitivity could be blocked by intrathecal pre- or posttreatment with a PKC inhibitor, chelerythrine chloride (CH), while a PKA inhibitor, N-(2-[P-bromocinnamylamino]ethyl)-5-isoquinolinesulfonamide hydrochloride (H89), had no effect. (2). BV-induced primary mechanical hypersensitivity could be blocked by pre- or posttreatment with H89, whereas CH had no effect. (3). Both pre- and posttreatment with H89 produced suppressive effects on both induction and maintenance of the BV-induced PSN and MIH hypersensitivity. Based on the present findings, we proposed that spinal PKC might be activated during the central processes of primary heat hypersensitivity, while spinal PKA is likely to be involved in primary mechanical hypersensitivity induced by subcutaneous BV chemical injury. Taken together with our previous report however, spinal PKC and PKA are likely to be simultaneously involved in the central processes of both PSN and MIH hypersensitivity.

Animals↗

PubMedDate not supplied

High-risk HPV DNA detection rate in patients with atypical squamous cells and its relationship to the atypical squamous cell: squamous intraepithelial lesion ratio.

OBJECTIVE: To determine if there is any relationship between the atypical squamous cell (ASC):squamous intraepithelial lesion (SIL) ratio and high-risk HPV DNA detection rate. STUDY DESIGN: Data on the frequency of various cytologic diagnoses for each pathologist were retrieved from 2002 to 2003. ASC:SIL ratio for each pathologist was calculated. In addition, data related to high-risk HPV detection rate was obtained during the study period. HPV DNA testing was performed using HC II (Digene, Gaithersburg, Maryland U.S.A). Cases with insufficient quantity were excluded. RESULTS: Five pathologists, with experience ranging from 2 to 15 years, reviewed Pap tests during the study period. For the entire laboratory, the ASC:SIL ratio was 2.0, and the high-risk HPV DNA detection rate in ASC specimens was 31%. For individual pathologists, ASC:SIL ratio ranged from 1.2 to 4.0 and high-risk HPV DNA detection rate from 31% to 38%. No significant correlation was noted between the ASC:SIL ratio and high-risk HP DNA detection rate. CONCLUSION: Our ASC:SIL ratios (except for 1 pathologist) and high-risk HPV DNA detection rates were within an acceptable range. We did not observe any association between ASC:SIL ratio and high-risk HPV detection rate.

Cervix Uteri↗

PubMedDate not supplied

Analysis of stimulated Brillouin scattering in multi-mode fiber by numerical solution.

Stimulated Brillouin scattering in optical fibers is described by a theoretical model and numerical analysis. The results showed that, for an optical fiber pumped by a laser beam with ns-order-pulse width and kW-order peak-power, SBS reflectivity tends to saturate when the fiber length exceeds a limit, named "effective fiber length". Using small core-diameter and long enough fiber, the SBS reflectivity level could be raised but is limited by optical damage of the entrance surface of the fiber. Therefore, just a small dynamic range can be obtained.

Computer Simulation↗

PubMedDate not supplied

[Sequence, necessary for initiating RNA synthesis, in the 3'-noncoding region of the classical swine fever virus genome].

Classical swine fever virus (CSFV) is the causative agent of swine fever, which represents an economically important disease in hogs. We previously made a prediction about the recognition sites of replication initiation of CSFV by using the information content method, and it was predicted that the 21 nucleotides located at 3' end of the CSFV genome 3'UTR were essential to CSFV replication. In this paper, we experimentally studied these 21 nucleotides by site-directed mutagenesis. It was found that the 3'UTRs with the 21 nucleotides had the function of initiating RNA synthesis, while the 3'UTRs without the 21 nucleotides did not. The 21 nucleotides alone, without the rest of 3'UTR, were able to initiate RNA synthesis, though with a slump. It was demonstrated that the 21 nucleotides were essential to the replication of CSFV genome. The other part of 3'UTR was also required for sufficient RNA synthesis. It is highly likely that the 21 nucleotides were the necessary site for the CSFV genome replication initiation, and that the elements required for sufficient RNA synthesis were in the other part of 3'UTR. It was assumed that the CSFV replicase bound to the site and initiated the replication of the CSFV genome. In the 21 nucleotides, it was found that the mutation of position 216 and destruction of the 3' terminus in the 3'UTR precluded initiation of RNA synthesis, that the mutation of position 212 did not affect the capacity for initiation of RNA synthesis but attenuated the synthesis of RNA. Among the four mutants of 3'UTR at position 219, three produced the 3'UTR without initiation of RNA synthesis, and the other one produced the 3'UTR with initiation of less RNA synthesis. Therefore, it could be concluded that T216 was the most important while T212 was the least important, and that G219 and C228 were also important for RNA synthesis. The normal base component within the 21 nucleotides was essential to sufficient RNA synthesis.

3' Untranslated Regions↗

PubMedDate not supplied

Clipless needlescopic bilateral varix ligation.

We report a novel technique of clipless needlescopic bilateral varix ligation and compare its results with the conventional laparoscopic approach. The positions of ports and surgical procedures were similar to those of the conventional 3-port laparoscopic technique, but all 5- and 10-mm trocars were replaced by 2-mm trocars. The internal spermatic veins proximal to the internal inguinal ring were isolated and coagulated for an adequate segment with a 2-mm bipolar electrocautery apparatus and then transected. The perioperative parameters of 25 patients operated on in this manner were compared with a historical cohort of 25 patients operated on using the conventional laparoscopic approach. Both groups of patients had uneventful surgery with no complications. The mean amount of analgesics used (1.25 vs 3.68 mg of morphine sulfate equivalent, P=.03), the maximal and mean postoperative pain scores (3.5 vs 5.6 and 2.5 vs 4.0, respectively, both P <.05), the postoperative hospital stay (0.5 vs 1.1 days, P=.03), and convalescence to normal activity (0.56 +/- 0.3 vs 1.64 +/- 0.4 weeks, P=.01) were all significantly decreased in the needlescopic group. We conclude that needlescopic bilateral varix ligation not only is feasible and safe but also provides the same therapeutic efficacy of a conventional laparoscopic approach; most importantly, it causes less pain and yields faster convalescence and excellent cosmetic results.

Adult↗

PubMedDate not supplied

Differential expression of molecular markers in arsenic- and non-arsenic-related urothelial cancer.

BACKGROUND: Little is known about the mechanisms of arsenic-related urothelial cancer (AsUC). The aim of this study was to reveal the differential expression of molecular markers between AsUC and non-arsenic-related UC (non-AsUC). MATERIALS AND METHODS: Tissues of AsUC (n=33), non-AsUC (n=20) and normal bladder urothelia from patients with benign diseases (n=4) were examined for multiple selected molecular markers responsible for various cellular functions, includingglutathione, GST-pi, Bcl-2, p53 and c-Fos. RESULTS: The mean cellular glutathione content of normal mucosal samples (33.4 +/- 7.2 microM/mg protein) was significantly higher than either non-AsUC (22.8 +/- 1.8, p = 0.04) or AsUC (16.4 +/- 1.6, p = 0.002). The glutathione content of non-AsUC was higher than that of AsUC (p = 0.012). The expressions of Bcl-2 and c-Fos in AsUC were significantly higher than those in non-AsUC (p = 0.004 and p = 0.02, respectively). CONCLUSION: The carcinogenic pathway for AsUC is different, in part, from that of non-AsUC. Cellular glutathione contents may be down-regulated during urothelial carcinogenesis. Bcl-2 and c-Fos may play important roles in arsenic-mediated carcinogenesis of the urothelium.

Arsenic Poisoning↗