[Automatic hemacytometer applied for detecting white blood cell in the patients with severe jaundice hepatitis].
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Cholestasis, Intrahepatic↗
Biomedical subjects
Y Fan
Publications and source records attributed to Y Fan.
[The boundary design of mandibular model by means of the three-dimensional finite element method].
OBJECTIVE: To construct the mandibular model and simulate the boundary conditions by means of the three-dimensional finite element method. METHODS: A juvenile mandible, including TMJ, was scanned transversely by CT, then a three-dimensional finite element model of mandible was constructed. At the same time, the functions of stomatologic muscles and ligaments and the functional actions of temporomandibular joint (TMJ) were simulated by means of cable elements and compressive gap elements respectively. RESULTS: The cable elements were consistent with the functions of stomatologic muscles and ligaments, and the gap elements were similar to the boundary conditions of the TMJ and teeth. CONCLUSION: Cable and gap elements are reasonable boundary conditions of the finite element model of mandible, which will improve the similarity of the model.
Adolescent↗
[Computer-aided legal medical examination of body surface].
This paper provides a package of automatic and semi-automatic methods for computing the area of different kinds of body surface injuries. Compared with traditional methods, these processes of examination are faster and the conclusions are more precise and objective. Also presented are the authors classify the items into many types by standards which are necessary to let computer draw conclusions automatically. This software is conducive to improvement in work efficiency and convenience for judicial supervision.
Algorithms↗
[Three-dimensional finite element study on periodontal membrane of central maxillary incisor under physiological load].
This paper presents the development of a three-dimensional finite element model of central maxillary incisor. Stress distribution of the periodontal membrane was obtained by calculation under physiological load exerted to the natural tooth and tooth restored with post respectively. And it was compared with the stress distribution of the implate (contact with bone and without periodontal membrane). The result indicated that, under physiological load, when the natural tooth was compared with tooth restored with post, there were no apparent diferences in stress distribution of periodontal membrane and in stress values on inner surface and outer surface of periodontal membrane. It suggests that periodontal membrane has apparent cushioning action against stress.
Adult↗
[One-stage reconstruction with the pedicle skin flap of forehead for defective tissue of head-neck tumors dissection].
OBJECTIVE: To discuss the feasibility on reconstructing the defective tissue with the pedicle skin flap of forhead after head-neck tumors dissection. METHOD: 14 patients with advanced head-neck tumors were studied, whose defective tissues were reconstructed by their forehead skin flaps. The flap area ranged from 5 cm x 11 cm to 7 cm x 16 cm. RESULT: 2 cases of them were partial necrosis, 3 years and 5 years survival rates were 76.9% and 63.6% respectively. The function of breath through nose or mouth and the function of swallow were satisfactory. CONCLUSION: The forehead skin flap should be a good selection for the reconstruction of defective tissue after basicranial and nasalfacial dissection.
Adolescent↗
[79 cases: a clinical analysis of hoarseness in children].
OBJECTIVE: To research the clinical characters of the hoarseness in children. METHOD: 79 cases are analysed retrospectively. RESULT AND CONCLUSION: Age for this disease is usually 3 years old. People with irritable character are more easy to get it. Vocal nodule is the main cause to chronic hoarseness in children. Conservative treatment is important.
Adolescent↗
[Prevention of complications of endoscopic sinus surgery].
OBJECTIVE: To investigate the causes and prevention of the complications of endoscopic sinus surgery (ESS). METHOD: We summurized the complications of 26 cases among 100 patients who were performed the ESS operations. RESULT: The complications included hemorrhage, cerebrospinal fluid leak, orbital hematoma, subcutaneous orbital emphysema, synechia and antrotomy closure. CONCLUSION: We concluded the factors which probably result in complications and the prevention of complications.
Adolescent↗
[A new adaptive filtering method for micro-particle image processing].
Based on the local gray level histogram of macro-particle image which is more special than other images, a new adaptive noise filtering method for macro-particle image processing is developed and described in this paper. It is made up of median filter and special order statistic (OS) filters (alpha-mean filter and inverse alpha-mean filter). This adaptive filter not only has satisfactory performance in both of noise-removal and edge-preservation of macro-particle image, but also is easy and quick to implement. An example is presented in this paper.
Algorithms↗
[3-channels data acquisition system based on single-chip-microcomputer used in the measurement of coronary sinus blood flow].
The coronary sinus blood flow can be figured out, which based on the principle of thermodilution, so long as gets the temperature of blood, indicator and mixture of blood and indicator respectively. This system is a smart slave module with single-chip-microcomputer. The structure and principles of hardware and the flow chart of software are described in detail.
Blood Volume Determination↗
Reversion of the neoplastic phenotype of human glioblastoma cells by connexin 43 (cx43).
Connexins (cx), structural components of gap junction, are believed to play a role in the regulation of cell proliferation and suppression of the neoplastic phenotype. We used human brain glioblastoma tumor cells as a model system to test this hypothesis. Western blot and reverse transcription-PCR analysis indicate that the expression levels of the gap junction protein connexin 43 (cx43) are profoundly decreased in several human brain tumor cell lines examined. Transfection of human cx43 into human glioblastoma cell lines U251 and T98G profoundly reduces cell proliferation in monolayer culture, in soft agar, and in athymic nude mice. Surprisingly, these effects are not associated with the establishment of gap junction communication in cx43 transfected cells. We conclude that the loss of cx43 expression may play a role in the development of human gliomas and that cx43 acts as a tumor suppressor gene to human glioblastoma.
Animals↗
Phenotype and genotype of advanced premalignant head and neck lesions after chemopreventive therapy.
BACKGROUND: The goal of chemoprevention is to reduce the risk of cancer development by reversing or blocking the tumorigenic process through the use of pharmacologic or natural agents. To determine the potential role of genetic alterations in assessing cancer risk and in evaluating the efficacy of chemopreventive agents, we studied 22 patients with advanced premalignant lesions of the head and neck who were part of a prospective cancer prevention trial that is investigating a regimen of 13-cis-retinoic acid, interferon alfa, and alpha-tocopherol administered for 12 months or until disease progression. METHODS: We used polymerase chain reaction analysis of microsatellite DNA sequences in cells from precancerous lesions to determine the frequencies of genetic alterations--namely, loss of heterozygosity (LOH) and microsatellite instability--at chromosomal loci that are commonly deleted in head and neck cancer. RESULTS: Prior to treatment, 17 (81%) of 21, eight (44%) of 18, and eight (42%) of 19 patients who were informative (i.e., heterozygous) at chromosomes 9p21, 3p14, and 17p13, respectively, exhibited LOH in at least one of their lesion biopsy specimens. Among nine patients who exhibited LOH at chromosome 9p21 in pretreatment biopsy specimens and who had completed at least 5 months of therapy, the genetic loss persisted in eight--including three of the four patients who exhibited complete histologic responses (i.e., no evidence of dysplasia in their biopsy specimens). IMPLICATION: Our data suggest that clinical and histologic assessments of the response to chemopreventive agents may be insufficient to determine their efficacy and that critical genetic alterations could be used as independent biomarkers to augment the ability to evaluate the efficacy of such agents.
Antineoplastic Agents↗
[Identification of a mutation hotspot in exon 8 of Wilson's disease gene by cycle sequencing].
OBJECTIVE: To screen for mutation hotspot of Wilson's disease (WD) gene in Chinese. METHODS: Cycle sequencing was used to detect mutation in exon 8 of WD gene in 30 patients with WD. RESULTS: The same missense mutation, Arg778Leu, was identified in 14 WD patients, four of which were homozygous and the others were heterozygous for this mutation. The frequency of this mutation was 30%. CONCLUSION: The codon 778(CGG-->CTG) of exon 8 in WD gene was one of mutation hotspots in Chinese.
Adolescent↗
Mechanism of action of eukaryotic DNA topoisomerase I and drugs targeted to the enzyme.
DNA topoisomerase I is essential for cellular metabolism and survival. It is also the target of a novel class of anticancer drugs active against previously refractory solid tumors, the camptothecins. The present review describes the topoisomerase I catalytic mechanisms with particular emphasis on the cleavage complex that represents the enzyme's catalytic intermediate and the site of action for camptothecins. Roles of topoisomerase I in DNA replication, transcription and recombination are also reviewed. Because of the importance of topoisomerase I as a chemotherapeutic target, we review the mechanisms of action of camptothecins and the other topoisomerase I inhibitors identified to date.
Antineoplastic Agents↗
Suppression of human fibrosarcoma cell growth by transcription factor, Egr-1, involves down-regulation of Bcl-2.
Previously, we showed that the transcription factor Egr-1 suppressed the proliferation of v-sis transformed NIH3T3 cells and also a number of human tumor cells. Here, we investigate the possible mechanisms responsible for this function. We show that transfected Egr-1 in human fibrosarcoma cells HT1080 leads to down-regulation of Bcl-2. Transient CAT transfection assays reveal that expression of Egr-1 suppresses Bcl-2 promoter activity in a dose-dependent manner. Furthermore, overexpression of Bcl-2 in Egr-1-expressing HT1080 cells enhanced cell proliferation in monolayer culture and increased anchorage-independent growth. Our results suggest that suppression of tumor cell proliferation by Egr-1 may be at least partially mediated through the down-regulation of Bcl-2.
Blotting, Western↗
Gene expression of monocyte chemoattractant protein-1 in giant cell tumors of bone osteoclastoma: possible involvement in CD68+ macrophage-like cell migration.
Giant cell tumor of bone (GCT) is one of a few neoplasms in which the macrophage/osteoclast precursor cells and osteoclast-like giant cells infiltrate the tumor mass. Monocyte chemoattractant protein 1 (MCP-1) is a potent chemotactic factor specific for monocytes. In search of relevant cytokines that may enhance the recruitment of these reactive cells, we evaluated the localization and regulation of MCP-1 mRNA and protein in GCT by using Northern blot analysis, in situ hybridization and immunohistochemistry. We also determined whether conditioned medium obtained from GCT cultures can recruit human peripheral blood monocytes (CD68+) in an in vitro chemotactic assay. Using Northern blot analysis, we detected the specific gene transcript for MCP-1 in all GCT samples tested. In situ hybridization and immunohistochemistry revealed that both MCP-1 gene transcript and protein were consistently present in the cytoplasm of stromal-like tumor cells of GCT. Treatment of mononuclear cells from GCT at third passage with TGF-beta1 for 24 h increased the level of MCP-1 mRNA in a dose-dependent manner, with the maximum effect at 1 ng/ml. Conditioned media from GCT cultures promoted the chemotactic migration of CD68+ peripheral monocytes, an activity which was abolished by the addition of MCP-1 antibody to the conditioned medium. Thus, the results of this study suggest that recruitment of CD68+ macrophage-like cells may be due to the production MCP-1 by stromal-like tumor cells. These CD68+ cells may originate from peripheral blood and could have the capability of further differentiating into osteoclasts in the tumor.
Antigens, CD↗
Molecular modeling studies of the DNA-topoisomerase I ternary cleavable complex with camptothecin.
The present studies provide a three-dimensional model for the postulated ternary cleavable complex of topoisomerase I (top1), DNA, and camptothecin (CPT). Molecular simulations were done using the AMBER force field. The results suggest that a ternary cleavable complex might be stabilized by several hydrogen bonds in the binding site. In this proposed "drug-stacking" model, CPT is pseudointercalated in the top1-linked DNA cleavage site and interacts with the protein near its catalytic tyrosine through hydrogen bonding and stacking. The structural model is consistent with the following experimental observations: (i) the N3 position of the 5' terminal purine of the cleaved DNA strand is readily alkylated by 7-chloromethyl 10,11-methylenedioxy CPT; (ii) CPT generally tolerates substituents at positions 7, 9, and 10 but is inactivated by additions at position 12; (iii) 10,11-methylenedioxy (MDO) CPT is much more potent than 10,11-dimethoxy (DMO) CPT; (iv) the lactone portion of CPT is essential for top1 inhibitory activity; (v) 20S derivatives of CPT are much more potent than the 20R analogues; (vi) a catalytic tyrosine hydroxyl in top1 covalently links to the 3' terminal base, T, of the cleaved DNA strand; and (vii) top1 mutation Asn722Ser leads to CPT resistance. A total of 18 camptothecin derivatives with different DNA cleavage potencies were docked into the hypothetical cleavable complex binding site to test and refine the model. These studies provide insight into a possible mechanism of top1 inhibition by CPT derivatives and suggest rational approaches for the design of new CPT derivatives.
Amino Acid Substitution↗
[Rapid selection of the gradually shortened DNA clones by using PCR amplification].
OBJECTIVE: To establish a simple technique with which the gradually shortened DNA clones can be selected rapidly and accurately so that the sequencing and identification of the full length cDNA or longer DNA fragments can be performed as quick as possible. METHODS: Primers were designed according to the sequence flanking the multiple cloning site of pGEM vector and were used to amplify the inserted fragments in a series of deletion sub-clones originated from a clone. with longer DNA insert fragment. These sub-clones which contain the gradually shortened fragments can be selected directly. This method was compared with the routine method in which the restriction endonuclease was used to digest DNA samples. RESULTS: A series of deletion sub-clones were identified accurately with this new method and the cycle sequencing could be performed on these PCR products as well. This method was characteristic of more accurate, more simple and less time-consuming, compared with the routine method. CONCLUSION: The method presented is very effective for rapid selection of the gradually shortened inserted fragments constructed in pGEM vector. It can greatly save time and materials, and the strategy in the report could also fit for selecting the clones containing gradually shortened fragments in other plasmid vectors.
DNA, Complementary↗
An analysis of sex and breeding stage differences in prolactin binding activity in brain and hypothalamic GnRH concentration in Wilson's phalarope, a sex role-reversed species.
Wilson's Phalarope (Phalaropus tricolor) is a sex role-reversed species in which incubation of eggs and care of young is performed exclusively by the male. Plasma levels of prolactin (PRL), the hormone most associated with parental care in birds, are higher in incubating males than in nonincubating males or females. Conversely, plasma testosterone levels are reduced in males during incubation. In an attempt to characterize the physiological basis of this unusual parental care system we used quantitative film autoradiography and densitometry to measure the specific binding in vitro of 125I-ovine PRL to 12 brain regions in females, nonincubating males, and incubating males during the normal breeding season. We also measured hypothalamic chicken gonadotropin-releasing hormone I (cGnRH-I) in three brain areas in these same birds, as well as plasma levels of PRL and testosterone. Analysis revealed that cGnRH-I concentrations in the preoptic area and plasma testosterone levels were significantly lower in incubating males than in nonincubating males. Specific binding of 125I-ovine PRL was detected in choroid plexus and in several diencephalic brain regions of both sexes, with highest binding activity recorded in the dorsolateral thalamus, medial habenula, nucleus subrotundus, and preoptic area. When adjustments were made for the large number of comparisons performed, specific binding did not vary significantly by sex or breeding stage in any single brain region. However, average specific binding values in nonincubating males exceeded those of incubating males in 9 of the 11 PRL-sensitive regions examined. Increased occupancy of the receptor by endogenous PRL during incubation could have contributed to this result, since plasma PRL levels were elevated in incubating males. In addition, PRL binding activity in several of these brain regions tended to correlate negatively with plasma PRL. The two exceptions to this general pattern were the preoptic area and the lateral septum, where mean specific binding was 14-15% higher in incubating males than in nonincubating males. This raises the interesting possibility that PRL sensitivity is up-regulated during incubation in some regions of the male phalarope brain, such as the preoptic area and lateral septum, that have been implicated in PRL-modulated changes in behavior and reproductive activity during this breeding stage.
Animals↗