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Biomedical subjects

H L Chen

Publications and source records attributed to H L Chen.

At least 163 records · Page 9Linked to original sources
PubMed1993

Cytogenetic studies on human liver cancer cell lines.

Karyotyping of human liver cancer cell lines and chromosome in situ hybridization of hepatitis B virus (HBV) DNA was performed in order to elucidate the possible mechanism of hepatocarcinogenesis from evidence of chromosomal changes and HBV integration patterns. HepG2-2 and HepG2-5 cell lines were HepG2 cells experimentally transfected with HBV DNA; the HCC36 cell line was derived from a hepatocellular carcinoma containing integrated HBV DNA from a Taiwanese patient. HepG2 cells, a hepatoblastoma cell line without HBV DNA integration, served as negative control. In HepG2-2, HepG2-5, and HCC36 cells, multiple integrations of HBV DNA were observed by in situ hybridization and hybridization signals occurred preferentially on certain chromosomes: 2, 5, 10, 11, 18; 7, 10, 13, 17, 18; and 4, 6, 11, 12q+, 18; respectively. In addition, a strong correlation between chromosomal changes and HBV integration was noticed in HCC36 cells, especially at chromosome 12q+.

Carcinoma, Hepatocellular↗
PubMed1993

Tumor necrosis factor-alpha gene expression in mouse oocytes and follicular cells.

Ovarian cells that transcribe and translate the gene for tumor necrosis factor alpha (TNF alpha) were identified in the adult cyclic mouse by using in situ hybridization and immunocytochemistry. TNF alpha mRNA was observed in > 97% and protein was contained in approximately 53% of the oocytes of healthy follicles with two or more layers of granulosa cells, but neither was detectable in oocytes of primordial follicles and follicles with a single layer of granulosa cells. In early atretic follicles, only 13% contained TNF alpha protein and 40% contained TNF alpha mRNA. In late stages of atresia, intense immunoreactive TNF alpha was observed in all of the oocytes, but TNF alpha mRNA was present in only 13%. In approximately 85% of follicles, theca and/or granulosa cells exhibited TNF alpha mRNA hybridization signals. Macrophage-like cells within the interstitium were positive for TNF alpha mRNA and protein. In corpora lutea, luteal cells and macrophage-like cells contained TNF alpha message, while only the latter lineage contained immunoreactive TNF alpha. Hybridization signals and immunoreactivity were more intense in older corpora lutea than in corpora lutea of the present cycle. Northern blot analysis revealed a 2.2-kb TNF alpha mRNA in the ovary that was unchanged relative to 28S rRNA (constitutive RNA) during the cycle. Similarly, TNF alpha hybridization signals and immunoreactivity did not appear to change throughout the cycle. These results indicate that TNF alpha gene transcription in the oocyte coincides with the synthesis of immunoreactive TNF alpha and that these complex biochemical processes occur at distinct steps of follicular development in the mouse.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Normal distribution of tumor necrosis factor-alpha messenger ribonucleic acid and protein in the uteri, placentas, and embryos of osteopetrotic (op/op) mice lacking colony-stimulating factor-1.

In order to map mouse tumor necrosis factor-alpha (TNF) gene expression in detail and to determine whether transcription or translation of the TNF gene is regulated by uterine colony stimulating factor-1 (CSF-1), preimplantation embryos, oviducts, uteri, and uteroplacental units were studied in various strains of mice. These included homozygous osteopetrotic (op/op) female mice, which completely lack CSF-1, and heterozygous (+/op) females, which have normal levels of CSF-1. TNF mRNA was identified in all samples except preimplantation embryos by use of Northern blot hybridization or reverse transcriptase polymerase chain reaction. In situ hybridization and immunocytochemical experiments showed that the TNF gene was expressed in mouse oviduct and uterine epithelial cells, decidual cells, macrophage-like cells, placental trophoblast, and embryos. Despite an absence of CSF-1, TNF gene expression in the uteri, placentas, and embryos of op/op mothers did not differ in any major respect from expression in +/op or other strains of mice. The results of this study therefore indicate that the TNF gene is transcribed and translated in an ordered sequence through mouse gestation, and that maternal CSF-1 is not essential to expression of this cytokine gene. Collectively, these findings are consistent with a major role for TNF in mouse reproduction and development and with a potential compensatory function for this potent polypeptide factor in CSF-1 deficiency.

Animals↗
PubMed1993

Expression of tumor necrosis factor-alpha in mouse spermatogenic cells.

Enriched fractions of spermatogenic cells were isolated by unit gravity sedimentation and analyzed both for the presence of secreted tumor necrosis factor-alpha (TNF alpha) in vitro by bioassay and for the presence of TNF alpha mRNA by Northern blot analysis. Small quantities of bioactive TNF alpha were consistently detected in medium conditioned by round spermatid fractions. Both pachytene spermatocyte and round spermatid fractions contained RNA that hybridized with murine cDNA probes for TNF alpha, with pachytene spermatocytes containing a normal 1.9-kilobase (kb) transcript, while round spermatids contained principally an approximately 2.8-kb transcript. Both the normal size transcript and the larger haploid-specific transcript were enriched when total RNA from pachytene spermatocyte and round spermatid fractions was passed through an oligo(dT) column. The normal 1.9-kb transcript within pachytene spermatocytes could be induced by exposing the spermatogenic cells to lipopolysaccharides in vitro, yet the approximately 2.8-kb transcript within round spermatids appeared uninduced by LPS treatment. In situ hybridization for the TNF alpha message by using digoxigenin label antisense TNF alpha riboprobe labeled pachytene spermatocytes, round spermatids, and presumptive interstitial macrophages. Spermatogonia and elongating spermatids as well as other interstitial cells were unlabeled or very lightly labeled. Hybridization of 16-day-old prepuberal testis resulted in the labeling of spermatocytes and presumptive interstitial macrophages. RNA from Sertoli cells, but not pachytene spermatocytes or round spermatids, hybridized with human TNF alpha receptor p60 probe in Northern blot analysis. These results are consistent with the working hypothesis that spermatids release TNF alpha, which is detected by Sertoli cells and may serve as a paracrine factor, regulating an as yet unidentified process in spermatogenesis.

Animals↗
PubMed1993

[Surveillance of scrub typhus in Taiwan].

Although scrub typhus, a rickettsial exanthematous febrile disease, has designated as a reportable communicable disease in Taiwan since 1955, only Pescadores island, Hualien and Taitung counties had more reported and confirmed cases. Suspected dengue fever and scrub typhus serum specimens sent from the Bureau of Health and health stations to this institute from January 1991 to December 1992 were tested for antibody to scrub typhus by indirect fluorescent antibody technique (IFA). The results showed that: 1) there were serologically positive cases in many counties except Hsinchu and Iilan, 2) the disease occurred mostly from July to October, 3) more males than females were infected and their age ranged from 21 to 60 years old with a peak of the twenties and 4) higher incidence rate in children under five years old was observed in Pescadores and Orchid islands. The above data call the attention of people and physicians to be aware of the fact that there were probable scrub typhus cases in every county in Taiwan.

Adolescent↗
PubMed1993

[Characterization of trimethoprim resistance in Shigella].

Ninety-seven Shigella strains from 1982 to 1987 were isolated. When these isolates were tested with minimal inhibitory concentrations of trimethoprim, twenty-two were found to be resistant. Among these, 10 were found to be S. flexneri, and 12 to be S. sonnei. In addition, all of these 22 isolates were found to have multiple drug resistance. In order to determine the type of dihydrofolate reductase (DHFR) genes in these 22 trimethoprim-resistant isolates, colony hybridization with probes representing types I, II, III and V DHFR, were used. The results revealed the presence of type I DHFR gene in all of these isolates. Further southern hybridization indicated that the type I DHFR gene was located on plasmids. In order to determine whether a trimethoprim resistant gene existed as a functional transposable element in these isolates, we used a specific probe to detect the prevalence of Tn7. However, no positive hybridization was found. The relationship between the trimethoprim resistant gene and integron is characterized by the fact that the integrase gene, in our study, was frequently found in all of the 22 resistant isolates. These results indicate that trimethoprim resistant genes might transfer among bacteria via site-specific integration.

Serotyping↗
PubMed1992

A histofluorescent study of sympathetic innervation of human palatine tonsils.

The glyoxylic catecholaminergic histofluorescence method was employed on human palatine tonsil specimens in order to study the sympathetic innervation present. One percent neutral red was used as a counterstain. Abundant sympathetic fibers were demonstrable around the blood vessels of the medulla and capsule. However, few sympathetic fibers were found around the vessels of the subepithelial connective tissue and interfollicular septa. In the areas of the follicle and extrafollicle where B and T lymphocytes were located, sympathetic fibers were not found. These findings indicate that if sympathetic innervation can affect T and B cells, it will do so indirectly. Results also show that there is a higher norepinephrine content in focally infected tonsils that is not due to hyperactivity of the sympathetic nerve, but may be due to other mechanisms. Finally surgical dissection at the capsule during tonsillectomy will reduce bleeding, perhaps because vessels there have an abundant sympathetic innervation that leads to good vessel contraction.

Adrenergic Fibers↗
PubMed1992

Transcription of BamHI-A region of the EBV genome in NPC tissues and B cells.

Analysis by Northern blotting and sequencing of cDNA clones from a transcription library of a tumor biopsy from a nasopharyngeal carcinoma (NPC) patient showed that the BamHI-A region of the Epstein-Barr virus genome is abundantly and regularly transcribed in tumor tissues from NPC patients. The transcription occurred in a rightward direction terminating between coordinates 160,965 and 160,995, where two polyadenylation sites are located. Rightward transcription of this region also occurred in B lymphoid cells harboring the viral genome, albeit at a lower level than in the tumor tissues. Differential splicing yields a family of related transcripts displaying at least four splicing patterns. Different promoters may be utilized, further contributing to the diversity of this family of transcripts. A 2.8-kb unspliced transcript present in B95-8 cells was probably initiated from a TATA box located in position 158,204, while the other transcripts may utilize other promoters localized to other regions. All the transcripts encompass a putative open reading frame, BARFO, which is predicted to encode a basic protein of about 20 kDa. It shares 40% colinear amino acid sequence homology with the DNA binding region of a transcription factor, ICP4, specified by herpes simplex virus.

Amino Acid Sequence↗
PubMed1992

Tumor necrosis factor-alpha gene expression in the tissues of normal mice.

Although TNF-alpha is traditionally associated with macrophage activation during neoplasia and acute inflammation, recent Northern blot hybridization studies indicate that gene expression occurs in the absence of pathology. In order to identify the cellular sources of endogenous message and protein, normal mouse tissues were tested for TNF-alpha mRNA using in situ hybridization and for the corresponding protein by immunocytochemistry. Unexpectedly, specific TNF-alpha message was readily detected in hepatocytes, kidney tubule epithelial cells, various populations of spleen cells and neurons. TNF-alpha protein was present in the same liver and kidney cells as those that contained TNF-alpha mRNA, was low in spleen cells, and was absent in neurons. These results suggest that cells other than macrophages are the major sources of TNF-alpha gene products in normal tissues, indicate that regulation is accomplished by more than one mechanism, and are consistent with the postulate that products of this gene contribute to normal physiological processes.

Animals↗
PubMed1992

Tumor necrosis factor-alpha messenger ribonucleic acid and protein in human endometrium.

Although previous studies have shown that the tumor necrosis factor-alpha (TNF) gene is expressed in pregnancy decidua, it has not been determined whether this gene is transcribed or translated in the endometrium prior to implantation. To address this question and to identify cells expressing the TNF gene, samples of normal cycling human endometria were tested for TNF mRNA by in situ hybridization using a biotinylated antisense RNA probe, and the corresponding protein was localized in the same tissues by immunocytochemistry with a monoclonal antibody to TNF. Both TNF message and protein were identified in the endometrium throughout the menstrual cycle, and the same types of cells that contained transcripts also contained protein. As judged by the intensities of the hybridization signals, TNF mRNA increased during the proliferative phases, declined in the early secretory phase, and again rose during mid-to-late secretory phases, suggesting positive associations with levels of female sex hormones that show similar cyclic fluctuations. At the initiation of the cycle, transcripts were primarily localized to glandular epithelial cells whereas by the midproliferative phase, message was also present in stromal cells. Hybridization signals were consistently more intense in functionalis-region than in basalis-region stromal cells, and were frequently stronger in basalis-region glandular epithelia than in functionalis-region glands. These observations document that the TNF gene is expressed in normal cycling endometria, suggest that ovarian hormones may regulate TNF gene transcription, and identify differences in specific endometrial compartments. The findings are also consistent with the postulate that TNF is a local mediator of cellular communications in the human endometrium.

Adult↗
PubMed1992

[Cerebrospinal fluid rhinorrhea due to sinus surgery: a case report].

Cerebrospinal fluid rhinorrhea is an uncommon but dangerous disease. Many lethal complications, such as bacterial meningitis and pneumoencephalus, may be the result of cerebrospinal fluid rhinorrhea. Otolaryngologist, neurosurgeons and radiologists must know how to diagnose, how to localize the site of leakage and how to choose the best method of treatment. A case of cerebrospinal fluid rhinorrhea and meningitis due to improper sinus surgery is presented. Satisfactory result, such as avoidance of unnecessary brain tissue damage, can be obtained by extracranial endonasal repairing of the fistula with a composite septal flap.

Adult↗
PubMed1992

AGNORS in skin lesions of cutaneous malignant lymphomas and pseudolymphomas.

Nucleolar organiser regions (NORs) are loops of DNA situated on the short arms of acrocentric chromosomes 13, 14, 15, 21, and 22. They can be demonstrated in formalin-fixed paraffin-embedded sections by a one step silver technique; the resultant black structures are called AgNORs. The technique was used in 71 patients with cutaneous malignant lymphomas (CML) and 9 cutaneous pseudolymphomas (CPL). AgNORs in 200 nuclei were scored and the means, standard deviation and standard error of the means calculated. Counts were as follows: mycosis fungoides (MF) I (premycotic stage) 1.17 +/- 0.09, SEM = 0.01; MF II (infiltrating stage) 1.17 +/- 0.01, SEM = 0.02; MF III (tumor stage) 3.55 +/- 0.87, SEM = 0.43: cutaneous peripheral T cell lymphomas other than MF and Sezary's syndrome (SS) (CPTL) 2.55 +/- 1.11, SEM = 0.35; SS 1.52; cutaneous B cell lymphomas (CBCL) 2.18 +/- 0.18, SEM = 0.06; CPL 1.17 +/- 0.1, SEM = 0.03. There was a significant difference between counts for CML (MF III, CPTL, CBCL and SS) and CPL. Significant difference was also noted between scores for MF III and CBCL, and especially counts between tumor stage (MF III and CPTL) and pretumor stage (MF I and MF II) of cutaneous peripheral T cell lymphomas. Although the AgNOR technique is in the stage of research, it proves to be helpful in differentiating CML and CPL other than separating MF I and MF II from CPL.

Adolescent↗
PubMed1991

Tumor necrosis factor-alpha mRNA and protein in rat uterine and placental cells.

The pregnant uterus contains TNF-alpha, a potent cytokine with pleotrophic effects. The uterus also contains numerous macrophages, which are well described sources of TNF-alpha. In order to determine if uterine TNF-alpha originated with these macrophages, patterns of macrophage tissue distribution and population densities were first established in rat uterine tissues from early, mid, and late stages of gestation by immunohistology. The potential of these and other uterine and placental cells to synthesize TNF-alpha was then tested by in situ hybridization with the use of biotinylated antisense and sense RNA probes. Although TNF-alpha mRNA was present during all stages of pregnancy, hybridization signals were highest in gestation day 15 tissues. The predominant TNF-alpha mRNA-containing cells were uterine epithelium, decidual cells, and placental trophoblast cells; these cells also contained immunoreactive TNF. Transcription of the TNF gene in the uterus and placenta was also documented by Northern blotting experiments, which showed that the transcript sizes for uterine, placental, and macrophage TNF mRNA were similar. Although stromal cells that were located in macrophage-rich uterine compartments (myometrium, metrial gland) contained TNF-alpha mRNA, the cells did not contain high levels of immunoreactive TNF-alpha. Thus, cells other than macrophages are likely to be the major contributors of TNF-alpha during uncomplicated pregnancy in the rat.

Animals↗
PubMed1991

Immunomopharmacological effects of polysaccharides from Acanthopanax senticosus on experimental animals.

Polysaccharides PES isolated from a common Oriental herb Acanthopanax senticosus were found to have a wide spectrum of immunomodulatory activities on experimental animals. The potential usefulness of these polysaccharides is suggested in the observations that PES inhibited transplanted tumor growths and ameliorated toxicities of the toxic substances in experimental animals. Of most interest is the observations that they suppressed human TB propagation in mice and guinea pigs, as evaluated by lymph node responses and OT skin tests in the guinea pig model, and the quantitation of the TB in the lungs in the mouse model.

Animals↗
PubMed1991

In-vivo effects of amrinone and milrinone on left ventricular dP/dt, intraventricular pressure and heart rate in pentobarbital-anesthetized guinea pigs.

The cardiovascular properties of amrinone and milrinone were investigated in pentobarbital-anesthetized guinea pigs (in vivo). A 19g needle, attached to a pressure transducer, was inserted through the chest wall into the left ventricle. Continuous monitoring of intraventricular pressure and heart rate was recorded. The first derivative of this pressure pulse was dP/dt, an index of inotropic state. At a dose of 500 ug/Kg, amrinone given intravenously caused an increase in the rate of rise in left ventricular pressure (LV dP/dt) by 28.7 +/- 7.8% (from 928 +/- 34 to 119 +/- 73 mm Hg/sec., p less than 0.05). At 50 ug/Kg, milrinone (i.v.) caused an increase in the left ventricular peak positive dP/dt by 15.3 +/- 3.4 (from 942 +/- 24 to 1086 +/- 32 mm Hg/sec., P less than 0.001). Both amrinone and milrinone, in addition to vasodilating effect, exerted a concentration-related manner with these positive inotropic actions.

Amrinone↗
PubMed1991

[Effect of da cheng qi decoction co. on endotoxemia in obstructive jaundice].

The role of da cheng qi decoction co. (DCQDC) in preventing endotoxemia in obstructive jaundice has been investigated. A prospective study was performed on 43 consecutive patients with obstructive jaundice undergoing surgery. 24 patients were given oral DCQDC before operation and were compared with 19 jaundiced control patients and 17 non-jaundiced control patients. The incidence of endotoxemia was reduced in perioperative portal (P less than 0.05) and postoperative systemic (P less than 0.01) blood samples in the DCQDC treated group, and a significant fall of the postoperative 24h creatinine clearance (P less than 0.01) and the plasma fibronectin level (P less than 0.01) occurred in jaundiced controls compared with the DCQDC treated group. DCQDC may reduce endotoxin absorption by a reduction or alteration of gut flora thereby reducing the endotoxin pool available for absorption as well as by a direct effect on endotoxin. Result of this study indicated that DCQDC had a beneficial effect on endotoxemia or outcome in obstructive jaundice.

Cholestasis, Extrahepatic↗
PubMed1991

Tumor necrosis factor alpha mRNA and protein are present in human placental and uterine cells at early and late stages of gestation.

Tumor necrosis factor alpha (TNF-alpha), a polypeptide that regulates cellular growth and modulates the synthesis of various cell surface and secreted molecules, has been identified in the pregnant uterus. To determine which specific cells transcribed and translated this gene, extraembryonic fetal tissues (placenta and membranes) and uterine tissue from early and late stages of gestation were analyzed for TNF-alpha mRNA by in situ hybridization using biotinylated antisense and sense TNF-alpha probes, and for immunoreactive TNF-alpha using two monoclonal antibodies. Tumor necrosis factor-alpha transcripts and protein were identified in both extraembryonic and maternal cells. In first-trimester placental villi, TNF-alpha mRNA was present in syncytiotrophoblast but was low to absent in cytotrophoblast and villous stromal cells. Decidual and epithelial cells in maternal tissues contained TNF-alpha transcripts. In term placentas, both syncytiotrophoblast and villous stromal cells contained TNF-alpha mRNA, and transcripts were present in maternal cells in the decidua adjacent to the extraplacental membranes. In both first-trimester and term tissues, coincident expression of TNF-alpha mRNA and immunoreactive TNF-alpha was demonstrated. The results of this study show that TNF-alpha is synthesized by cells in both extraembryonic membranes and maternal tissues during human gestation and that transcription in specific types of cells is influenced by gestational age. These observations are consistent with a major role for TNF-alpha in the dynamic developmental events of human pregnancy.

Delivery, Obstetric↗