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Biomedical subjects

B F Chen

Publications and source records attributed to B F Chen.

At least 55 records · Page 3Linked to original sources
PubMed1995

Gastric carcinoma: recent issues in prognostic factors.

The prognosis of gastric carcinoma remains unfavorable despite a greater understanding of its molecular pathology. This retrospective study of primary gastric carcinomas was collected from one of the highest risk regions of China and examined for the oncogenetic expression of p53, c-erbB-2, and PCNA using immunohistochemistry and DNA contents by flow cytometry and image analysis. These products are reported to influence the tumor behavior. The p53 nuclear and c-erbB-2 membrane-bound stainings were seen in 58% and 34% of cases, respectively. A high PCNA index was found in 90% of the tumors. The p53 expression did not correlate with the histological differentiation, gross morphology, and depth of tumor invasion. Additionally, p53 and c-erbB-2 reactivity did not correlate with the proliferative index (PI) or S-phase DNA content. However, the mutant p53 expression was detected in the dysplastic cells adjacent to the tumor, suggesting a possible role of the oncogene in tumor pathogenesis. Mutant p53 expression can also be helpful in early detection of cases with dysplasia in well-differentiated adenocarcinomas.

Adenocarcinoma↗
PubMed1994

Subaortic blind mitral pouch in a double-inlet right ventricle.

A full-term baby girl was diagnosed at birth using echocardiography to have a single ventricle with common atrioventricular valve and subaortic ridge. On the 22nd day after birth she was admitted to hospital for intensive care after sudden onset of cyanosis. Three days later she died after repeated attacks of bradycardia. At necropsy the heart was examined by sequential segmental approach. Situs solitus with double-inlet right ventricle and ventriculoarterial discordance was revealed. The left atrial floor was separated from the ventricle by a small hole leading to a translucent blind pouch, which bulged toward the subaortic outflow tract with its hypoplastic tensor apparatus connected to the subaortic infundibulum. The aortic valve was normal. The pulmonary trunk with a competent bicuspid valve arose from the left-sided rudimentary left ventricle. The pulmonary blood flow was limited by a slit-like interventricular communication. Obstruction of the pulmonary venous return due to the natural closing of the patent foramen ovale and the mitral atresia led to her premature death.

Female↗
PubMed1994

A clinicopathological study of Langerhans cell histiocytosis.

BACKGROUND: Langerhans cell histiocytosis encompasses a wide clinical spectrum, from a benign localized disease to acute generalized disease with fatal outcome. Here the histological features and clinical data for thirteen patients are reviewed and compared. The antigenic phenotype of the proliferating cells in Langerhans cell histiocytosis was also studied. METHODS: The antibodies used included S-100 protein, vimentin, peanut agglutinin, HLA-DR, leukocyte common antigen, UCHL-1, CD 20, lysozyme, alpha 1-antitrypsin and epithelial membrane antigen. RESULTS: Six patients had localized lesions affecting a bone or its surrounding soft tissue. Four patients had multifocal disease without organ dysfunction. All patients of these two categories survived, except for one adult who died of hypertensive cerebral hemorrhage. Three patients had multifocal disease with liver, lung or bone marrow dysfunction. One died and two were lost to follow up. CONCLUSIONS: There was no significant difference in pathological findings between localized disease and multifocal disease. Immunohistochemical examinations using a panel of antibodies, including S-100 protein, peanut agglutinin, HLA-DR and vimentin, were very helpful for diagnosis of Langerhans cell histiocytosis.

Adult↗
PubMed1993

Characterization of a bicistronic retroviral vector composed of the swine vesicular disease virus internal ribosome entry site.

We cloned the 5' nontranslated region (NTR) from the genome of swine vesicular disease virus (SVDV), a member of the family Picornaviridae, and used it to construct a bicistronic retroviral vector. The vector is characterized by coexpression of two genes from a single transcript. We found that inclusion of the 5' NTR of SVDV did not negate the viral vector titer. Protein analysis indicated that the 5' NTR could efficiently direct internal initiation, thus allowing the downstream gene to be translated. Translation of the internally initiated porcine growth hormone gene was about 30-fold less than that when the porcine growth hormone gene was at the upstream position in NIH 3T3 cells but was about equivalent to that in HeLa cells, implying that some cellular factors that stimulated internal initiation of the SVDV 5' NTR are present in HeLa cells. However, in G418-selected clones, the Neor-encoding gene was expressed with equivalent efficiency either at a downstream position or at an upstream position in either NIH 3T3 or HeLa cells. Compared with the conventional double-gene vector or the U3-based vector, the bicistronic vector coexpressed two genes much more efficiently, owing to elimination of promoter interference. Furthermore, this type of vector infected and expressed the target genes efficiently in two primary cell lines, rat embryo and human skin fibroblast cells, which we tested. These experimental data suggest a better design for the retroviral vector and provide evidence that internal initiation of the SVDV 5' NTR was stimulated cell specifically.

3T3 Cells↗
PubMed1993

Rapid preparation of tissue DNA from paraffin-embedded blocks and analysis by polymerase chain reaction.

We have developed a new, easy, and more rapid method for DNA preparation, which avoids contamination. With this method, manual surgical blade scrapings from precisely targeted areas of paraffin block surfaces, without microtome cutting, were used to obtain tissues from 10 different neoplasms. Our results indicate the feasibility of DNA extraction from the scraped paraffin tissue for molecular genetic analysis. We applied this technique successfully to screen for the presence of human papillomavirus using the polymerase chain reaction (PCR) procedure in cases of endocervical, esophageal, and nasopharyngeal carcinomas, and to examine the expression of p53 gene from prostate and gastric adenocarcinomas. We conclude that this procedure is also suitable for purification of PCR products in analysis of the mutation or loss of allelic genes by Bstu I endonuclease digestion.

Base Sequence↗
PubMed1993

An angiogenic factor from human bladder cancer: the investigation of purification and biological activities.

An angiogenic factor from human transitional cell cancer of bladder has been purified by protein extraction, cation exchange chromatography, gel filtration high-performance liquid chromatography (GE-HPLC) and reversed-phase high-performance liquid chromatography (RP-HPLC). The purified substance was named bladder cancer angiogenic factor (BCAF). Biological activity of the BCAF was assessed by the method of chick embryo chorioallantoic membrane (CAM) assay and 3H-TdR incorporation into DNA in Balb/C 3T3 cells. The BCAF displayed the potent activities of neovascularization in CAM and DNA synthesis in Balb/C 3T3 cells. The ultrastructural features of blood vessels induced by the BCAF were similar to the blood vessels in tumors. The BCAF contained a protein with an approximate molecular weight of 15,000 D which was identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and silver staining. Amino acid compositions of the BCAF were also analysed by acid hydrolysis.

3T3 Cells↗
PubMed1993

[Evaluation of the apical seal of endodontically treated teeth by the ion-diffusion method].

It is generally accepted that improper preparation of the post space in endodontically treated teeth may damage sealing of the filling and cause treatment failure. Conventional method of detecting the sealing ability of endodontically treated teeth are quite complicated and inconvenient. To avoid the shortcomings of these traditional methods, the law of diffusion was adopted in this experimental design, and the results were compared with those of the traditional dye penetration method. Fifty sound molar teeth were treated by routine endodontic procedures, and were instrumented to 35# endodontic file. In 20 teeth in the control group, half were treated as a positive control by leaving the apical foramen open, and the remaining half were used as a negative control by sealing the foramen with two layers of nail polish. The other 30 experimental teeth were filled with gutta-percha points and sealer Canals by the lateral condensation method. Two weeks later, the filling material was removed to apical 3 mm, then 60 microL 2915 mM KCl solution was placed into the pulp cavity. The root was immersed into 1 mL 24.17 mM KCl solution. During the following 30 days, the concentration of the potassium ions in the outer solution was monitored by an ion-selective electrode. Finally, all 50 teeth were immersed in 1% methylene blue for 24 hours, sectioned with Isomet, and the extent of dye penetration was measured under a stereomicroscope with a digital caliper. The results of both methods were compared by means of regression analysis. There was a good correlation between the dye penetration method and the newly designed ion-diffusion method (r = 0.812).(ABSTRACT TRUNCATED AT 250 WORDS)

Dental Leakage↗
PubMed1993

[Polymerase chain reaction in detection of human papillomavirus DNA in esophageal carcinoma].

The polymerase chain reaction (PCR) was used to detect and type HPV DNA in 40 cases of esophageal carcinoma, which were collected from the high risk region in Fujian. Twenty-four 60% of the 40 patients were positive for HPV DNA after esophagotomy. HPV 6 DNA was found in 12 (50%) of the 24 patients HPV 16 DNA in 2 (8%), but HPV 6, HPV 16 in 4(17%) and HPV unknown type in 6(25%). No reaction was found for HPV 18 and 11. HPV 16 and 6 were detected in 2 lymph nodes with metastatic carcinoma. HPV types were in accordance with their primary tumors. HPV effects on esophagus mucosa adjacent to tumors in 27 cases consistent with cervical lesions. Among them, koilocytosis of statistically significance (P < 0.05). The evidence showed that HPV may be a possible etiological agent for esophageal carcinoma in high risk regions.

Adult↗
PubMed1993

Purification and characterization of human hepatic stimulator substance.

Human hepatic stimulator substance (hHSS) was purified from fetal liver with 6,000-fold decrease in protein content and 840-fold increase in specific growth stimulative activity. Purification procedures included the heating of a homogenate in 35% (W/V) Tris-HCL at 95 degrees C for 20 min, high and ultra speed centrifugation, passage over Sephadex G100 gel filtration, DEAE-cellulose ion exchange, TSK G3000 SWG high performance liquid chromatography (HPLC) and YWG C-18 reverse phase HPLC techniques. The most purified material (HP-HSS) revealed cell-specific and dose dependent increase in 3H-TdR incorporation into cellular DNA. As little as 38 ng of the HP-HSS per ml of culture medium produced a 2.5-fold increase in DNA synthesis. Further studies indicate that HP-HSS in combination with insulin and epidermal growth factor stimulate DNA synthesis 16-fold compared with serum and hormone free controls and nearly 3-fold over hepatoma growth with HP-HSS alone. Sodium dedecyl sulfate polyacrylamide gel electrophoresis with silver stain and ultrascan XL laser densitrometer quantitative scanning revealed only one band at 12,800.

Carcinoma, Hepatocellular↗
PubMed1992

Improved gene expression by a U3-based retroviral vector.

To improve the expression of the genes transduced by retroviral vectors, we have constructed a U3-based retroviral vector and evaluated its effect on the expression of an insert from the internal promoter. The unique feature of the vector is that the transduced gene is inserted at the U3 region of the 3' long terminal repeats (LTR). Consequently, in the infected cells the gene is duplicated and transferred to the 5'-LTR. When compared with the conventional retroviral vectors which insert the gene within the retroviral transcriptional unit, the U3-based vectors greatly enhanced the expression of the transduced gene under all three promoters tested, viz. the cytomegalovirus immediately early gene promoter (CMV), the SV40 early gene promoter (SV), and the herpes simplex virus thymidine kinase gene promoter (TK). The SV and TK promoters which were previously shown suppressed by the retroviral promoter in the conventional construction restored their potencies in the U3-based vectors. Our results therefore suggested that the U3-based vectors are more advantageous than the conventional vectors for gene expression.

Animals↗
PubMed1992

Meconium ileus-like condition in Chinese neonates.

Between January 1985 and May 1990, 16 neonates were treated for meconium ileus (MI) at this hospital. All babies were born to Chinese couples. Seven of them were premature, but none of them weighed less than 1,000 g. Eight patients underwent operations either because of mistaken diagnosis, as ileal atresia or long-segment Hirschsprung's disease, or because of complicated MI, including two meconium peritonitis and one associated with ileal atresia. Gastrograffin enema was successful in management of eight uncomplicated MI. The albumin content in the meconium of the last nine cases, including four complicated cases, ranged from 9.2 to 93.3 mg/g dry meconium. Usually, albumin is not present in normal meconium. All cases received sweat test, which were negative. Three patients died in the follow-up period. Sepsis of unknown origin, multiple congenital anomalies, and severe metabolic problems were the causes of death. The other 13 patients are doing well. They have exhibited no pulmonary or digestive problems during their follow-up period, which ranged from 11 months to 5 years. They are healthy and receive regular diets. Growth and development are appropriate for their age groups.

Albumins↗
PubMed1992

[AgNOR in the pathologic differential diagnosis of tumors].

AgNOR staining technique was applied to facilitate the pathologic differential diagnosis of 74 breast tumors and 95 non-Hodgkin's lymphoma (NHL). The results showed that the mean AgNOR count per nucleus was significantly different between benign and malignant tumors (P less than 0.01). An AgNOR count per cell less than 3 indicated benign breast lesion and more than 5 implied malignancy. In NHL, AgNOR count that nucleolus less than 4 was indicative of low-grade while more than 6 of high-grade malignancy. In 45 NHL patients followed up, the AgNOR count/cell was high in 28 patients with short survivals than otherwise (17 patients). These observations suggest that the AgNOR could provide useful information about the nucleolus activity in hyperplastic and neoplastic conditions. Electron microscopically, argyrophilic protein was irregular in shape and highly stained with silver in the fibrillar centers and the dense fibrillar component in NHL tumor cells as compared to that seen in normal lymphocytes. This further implies that the NOR Proteins could be used as a marker of ribosomal DNA and its level of transcription is higher in the malignant tumors.

Adenocarcinoma, Mucinous↗
PubMed1992

Use of helper-free retroviral vector to direct a high expression of porcine growth hormone in mouse fibroblast cells.

A retroviral vector has been employed to express the cDNA coding for porcine growth hormone (pGH) in the mouse fibroblast cell NIH 3T3 in large quantity. In this study, a single gene vector which contained no selectable marker was used. We have coinfected NIH 3T3 cells with pGH retrovirus and Neo(r) retrovirus to obtain a stable, high-expression clone. Using a superinfection strategy, we further increased the copy number of proviral DNA in the host chromosome, thus increasing the pGH secretion from 22 to 55 micrograms/10(6) cells/24 h. The recombinant pGH produced from mouse fibroblast cells was heterogeneous at the N-terminus, which mimicked the situation with bovine growth hormone either from natural sources or from recombinant products derived from mouse fibroblasts. This technology is useful for many biologically important genes to be stably transduced by retroviral vector into mammalian cells and highly expressed.

3T3 Cells↗
PubMed1991

Parosteal osteosarcoma: a case report.

Parosteal osteosarcoma is a low-grade malignant tumor arising from the periosteum. It involves mainly adults of third to sixth decades and the favorite site is the posterior aspect of distal femoral metaphysis. Microscopically, it is composed of woven to lamellar bone trabeculae within spindle cell stroma. We present a case of parosteal osteosarcoma that has very well-formed lamellar bone trabeculae and fat marrow under microscopic examination. Without the help of radiologic study, it is impossible to make the diagnosis of parosteal osteosarcoma.

Bone Neoplasms↗
PubMed1991

[Enzyme-and immuno-histochemistry of muscle biopsies in severe infantile spinal muscular atrophy].

The basic lesions in the muscle biopsies of 11 cases of severe infantile spinal muscular atrophy showed typical neurogenic fascicular muscular atrophy. It was found through histochemistry staining that both types of muscle fibres were involved which were characterised by the presence of type grouping of the damaged fibers, anyhow, the original mosaic pattern of both types were still partially reserved. With anti-laminin immunofluorescence staining, it was demonstrated that the basal membrane of atrophied small muscle fibre was still intact. It is considered that the main manifestation of damage on spinal anterior horn neuron is denervation of the skeletal muscle; meanwhile, the function of the muscle fibre in regulations carbohydrate metabolism is not apparently obstructs. The pathologic process of this disease develops from denervation to renervation and then back to denervation again. Therefore the clinical feature of muscle atrophy in this disease is progressive and developmental.

Anterior Horn Cells↗