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Biomedical subjects

J Ma

Publications and source records attributed to J Ma.

At least 289 records · Page 16Linked to original sources
PubMed1999

[Observations on prostate histology in 50 young and middle aged men. Its implication on clinical pathological diagnosis].

OBJECTIVE: To investigate the morphology and the relationship between the prostate and the adjacent structures in order to clarify its significance in histopathological diagnosis. METHODS: By means of light microscopy, and in part by electron microscopy and immunohistochemistry, the histology of 50 normal prostates were observed. RESULTS: The parenchymal component can be divided into four zones, i.e. peripheral zone, central zone, transitional zone and periurethral gland region, each characterized by its own anatomical and histological features. CONCLUSION: This 4 zone division of prostate has more clinical significance than the traditional division of the prostate. A good knowledge of the normal structure of the prostate has great practical significance in pathologic diagnosis.

Acid Phosphatase↗
PubMed1999

[Preservation of hearing and facial nerve function after Gamma knife therapy for acoustic neurinomas].

Thirty-five patients with acoustic neurinomas were treated by Gamma knife from Sept. 1995 to Oct. 1997. Neuroimaging studies performed in 21 patients with more than 12 months showed that tumor size decreased in 9(43%) cases, unchanged in 11(51%) cases, and increased in 1(15%) case. The tumor growth control and regression rates were 95% and 43%, respectively. Some hearing was preserved in four patients (36%) who had hearing prior to Gamma knife treatment. There was new transient facial weakness in five patients(23%), and there was new trigeminal neuropathy after treatment in one patient (4.8%). These findings indicate that Gamma knife therapy is a safe and effective management for acoustic neurinomas, especially in preventing facial function and hearing.

Adolescent↗
PubMed1999

[Differentiated remodeling changes of medium-sized arteries from different body parts in tail-suspended rats and their reversibility].

Objective. The aim of the present study was to test whether medium-sized arteries in different body parts are differentially directed to achieve stimulus-specific remodeling to adapt local hemodynamic changes induced by tail-suspension, and to examine whether these structural changes are reversible. Method. Morphological changes of femoral, anterior tibial, common carotid, and basilar arteries from 4 wk tail-suspended (SUS-4), 1 wk recovered (REC-1), and control (CON) rats were studied using van Gieson-Orcein staining method. Result. For the hindquarter arteries, like the femoral and anterior tibial arteries, the lumen diameter (d) and medial tissue area (A) of SUS-4 group were significantly decreased (P<0.05, P<0.01) as compared with that of CON group, and that of REC-1 group were not fully recovered though the differences were not significant. With respect to arteries in the neck region and the brain, the remodeling changes were just in an opposite direction. In SUS-4 group, the d and A of both common carotid and basilar arteries were significantly increased (P<0.05, P<0.01) as compared with that of CON, and not fully restored after 1 wk recovery. Conclusion. The structures of medium-sized arteries in different body parts remodel differentially in response to local hemodynamic changes during simulated weightlessness and these changes were reversible.

Adaptation, Physiological↗
PubMed1999

[Malignant melanoma of external ear: 14 cases report].

OBJECTIVE: To improve the diagnosis and treatment level of malignant melanoma in external ear. METHOD: 14 cases with malignant melanoma of external ear were reported. All patients were treated by surgical excision. RESULT: 13(in 14) cases were followed up. 7 patients were survival with no tumor, the others died. The 5-year survival rate for the whole series was 50.0%. CONCLUSION: The malignant melanoma of external ear has rapid progress and poor prognosis, early detection and treatment are necessary. Extensive excision of malignant melanoma was principle method of the treatment. Recurrent tumor should be treated by combined operation with radiation.

Adult↗
PubMed1999

[Immunohistochemical study of safe resection margin in the surgical treatment of laryngeal carcinoma].

OBJECTIVE: To study safe resection margin of laryngectomy according to the level of protein of gene expression. METHOD: Using citric-LSAB-immunochemical technique, the expressions of ras, c-myc and P53 were studied in different regions of larynx including 30 cases laryngeal carcinoma, border area, adjacent mucosa which was 0.5, 1.0, 1.5, 2.0 cm away from cancer and four normal laryngeal mucosa. RESULT: The results showed that both single expression and co-expression of p21, p62 and p53 increased as tissue progressed in sequence from normal mucosa, 2.0, 1.5, 1.0, 0.5 cm distant mucosa adjacent to carcinoma, border area and carcinoma. A significant different expression in most of them can be seen at regions of 0.5 cm and 1.0 cm distant from the tumor (P < 0.05). CONCLUSION: The tissue 0.5 cm adjacent to the tumor should be regarded as precancerous lesion. It is appropriate to regard 0.5 cm away from tumors as resection margins for surgical treatment of laryngeal carcinoma.

Adult↗
PubMed1999

[Dynamic changes in the expression of type VI collagen in mice with schistosomal liver fibrosis].

AIM: To clarify the dynamic changes in type VI procollagen mRNA expression and collagen content in mice with schistosomal liver fibrosis. METHODS: Northern blot hybridization and immunohistochemical technique. RESULTS: The expression of alpha 1(VI) procollagen mRNA measured by Northern blot hybridization in the liver of schistosome infected mice was elevated significantly at 8 wk post infection, peaked at 10 wk pi, slightly decreased at 12-16 wk pi, and sustained at high levels until 20 wk pi. Immunohistochemical assay revealed that the staining pattern of type VI collagen first appeared in the walls of central veins and liver sinusoids at 8 wk pi, then extended gradually to the egg granuloma and the portal tract, within and surrounding the egg granuloma to form dense reticular septum at the 12, 16 and 20 wk pi, respectively. The VI collagen content as indicated by the intensity of stain peaked at 16 wk pi. CONCLUSION: Both the expression of alpha 1(VI) procollagen and the content of collagen VI were significantly increased in the liver of mice with early schistosomal fibrosis, suggesting that the type VI collagen detection might be of importance for evaluating the intensity of schistosomal liver fibrosis.

Animals↗
PubMed1999

[Influence of radiation on the blood-brain barrier and optimum time of chemotherapy].

OBJECTIVE: A pilot study of the destructive effects of radiation on the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB) were carried out on 29 patients. METHODS: (1) First BBB with localized and limited brain tumors was examined by 99mTc-GH imaging count/pixel, data was obtained from the unirradiated, irradiated, and tumor areas of before and after radiotherapy of 20-40 Gy respectively. (2) The BCSFB was studied quantitatively by observing the effect of methotrexate (MTX) permeation into the CSF before, during, and after brain irradiated after i.v. injection of MTX. RESULTS: (1) the BBB in the unirradiated area outside the radiation portal was not changed, (2) the degree of destructive effect on the BBB in the irradiated normal area and on the BCSFB were directly proportional to radiation doses. CONCLUSIONS: When the permeation of BBB and BCSFB irradiated, was enhanced the degree of destructive effect were enhanced proportionally with irradiation doses. It was that the BBB irradiated can be recovered at least partially after irradiation of 3 weeks proved. After a dose of 20 Gy irradiation, the BCSFB would gradually open. As compared with the pre-radiation data, the permeability of MTX increased by 1.05-1.3 times. So, it was advisable to give chemotherapy after 20 Gy irradiation.

Antimetabolites, Antineoplastic↗
PubMed1999

[Subtractive cDNA cloning and analysis of murine erythroid terminal differentiation related factor].

OBJECTIVE: Cloning and identification of cDNA related to erythroid terminal differentiation factor (MEDRF). METHODS: cDNA related to erythroid terminal differentiation from the Friend virus anemia (FVA) infected splenic erythroblasts of BALB/c mice were performed by using subtractive hybridization combined with PCR technique. The splenic proerythroblasts isolated were cultured in the presence of erythropoietin for 36 hrs. Subtractive cDNA clones of differentially expressed in the 36 hrs erythroblasts (sub cDNA-36) but absent in the uncultured proerythroblasts were observed. The sub cDNA-36 was then used for construction of subtractive cDNA library using the Bluescript-SK(+) phage vector system, and differentially screened by 32P-labelled PCR generated probes. The positive clones were analyzed by nucleotide sequencing. RESULTS: The results indicated that a 472 bp cDNA fragment which contained a 309 bp reading frame from 51 to 359 coding 102 amino acids was identified and it has been accepted by GenBank as a new cDNA sequence that without comparable homology of existing sequences (accession number: AA114369). Northern blot analysis demonstrated that it was differentially expressed in the 36 hrs cultured intermediate-late stages of erythroblasts. CONCLUSIONS: The newly found cDNA, which expresses specifically in intermediate-late stages of erythroblasts, not in stages of proerythroblasts, may be a new gene related to murine erythroid terminal differentiation.

Activins↗
PubMed1999

Immunocytochemical study of cells in the vitreous of proliferative vitreoretretinopathy.

PURPOSE: To identify the cellular components of vitreous samples obtained during vitrectomy for proliferative vitreoretinopathy (PVR). METHODS: With the use of three intermediate filament (IF) proteins, vimentin, glial fibrillary acidic protein (GFAP), and cytokeratin (CK), cytocentrifuge slides of 14 fresh vitreous aspirates were detected with immunohistochemical technique. RESULTS: All the specimens contained epithelial-like proliferative cells with or without pigment and some membrane-like pieces. Immunocytochemical staining showed that 76.0-90.0% cells stained for CK, 17.4-29.6% cells expressed GFAP, and 80.1-91.0% cells were positive for vimentin. CONCLUSIONS: Majority of cells in the vitreous samples originated from retinal pigment epithelial cells (RPE) and glial cells in PVR. Expression of IF proteins may be determined by tissue of origin and local microenvironment.

Adolescent↗
PubMed1999

[Expression of vimentin in the lenses of vimentin transgenic mice].

PURPOSE: To observe the expression of vimentin in the lenses of vimentin transgenic mice and investigate the role of vimentin in the formation of cataract. METHODS: The 12.7 kb chicken vimentin genes were microinjected into the male pronuclei of ICR mice. The injected embryos were transferred to the pseudopregnant recipient females and then generated several transgenic mice. Twenty mice developed cataract by cross-breeding. Expression of vimentin in 4 cataractous lenses and 4 normal lenses were detected by ABC immunohistochemical method. Usig SDS-PAGE and Western blot technique, we seperated and measured vimentin in the normal and two cataract lenses, in which one was part opacity and the other was complete opacity. RESULTS: Besides in the epithelial cells, vimentin was overexpressed in the cells in anterior cortex and equatorial region in the lenses of transgenic mice. By SDS-PAGE and Western blot, 57 KD urea-soluble protein bands were seperated in normal and cataract lenses and were reacted with vimentin antiserum specifically. In normal lens, partly and completely opaque lenses respectively, the values of average grey density of these bands were 15.56, 34.59 and 33.06 and the percentages of vimentin in urea-soluble fraction were 7.26%, 9.05% and 9.17%, according to the sum of the grey level values of each band. CONCLUSION: Over and ectopic expression of vimentin in the Lenses of transgenic mice inhibits the lens cell differentiation and is linked to cataract formation.

Animals↗
PubMed1999

[The development of an intelligent vision testing instrument].

The paper introduces an intelligent vision testing instrument, which works on automatic method or manual method. The examinee inputs his or her judgement about the direction of the letter "E" with remote control. The system examines and judges the examinee's judgement, and then prints the testing report. The vision testing range is from logarithm vision 3.0 to 5.3. The distance between examinee and optometer can be measured automatically by the system with infrared and ultrasonic testing functions and a good accuracy.

Diagnosis, Computer-Assisted↗
PubMed1999

[Measurement of cadmium content in soils and vegetables by FAAS].

The analytical and testing centre the total cadmium (Cd) and the available Cd contents in different Cd-polluted soils were measured by FAAS. The Cd content in the stems and leaves of cole was tested in the same way. The methods of sample pretreatment for the total Cd and available Cd in soils and in cole were compared respectively. The standard sample recovery rates were all above 96 percent, and the relative standard deviations were less than 3.97 percent. The FAAS is rapid and accurate.

Brassica↗
PubMed1998

Yeast chorismate mutase in the R state: simulations of the active site.

The isomerization of chorismate to prephenate by chorismate mutase in the biosynthetic pathway that forms Tyr and Phe involves C5---O (ether) bond cleavage and C1---C9 bond formation in a Claisen rearrangement. Development of negative charge on the ether oxygen, stabilized by Lys-168 and Glu-246, is inferred from the structure of a complex with a transition state analogue (TSA) and from the pH-rate profile of the enzyme and the E246Q mutant. These studies imply a protonated Glu-246 well above pH 7. Here, several 500-ps molecular dynamics simulations test the stability of enzyme-TSA complexes by using a solvated system with stochastic boundary conditions. The simulated systems are (i) protonated Glu-246 (stable), (ii) deprotonated Glu-246 (unstable), (iii) deprotonated Glu-246 plus one H2O between Glu-246 and the ether oxygen (unstable), (iv) the E246Q mutant (stable), and (v) addition of OH- between protonated Glu-246 and the ether oxygen. In (v), a local conformational change of Lys-168 displaced the OH- into the solvent region, suggesting a possible rate-determining step that precedes the catalytic step. In a 500-ps simulation of the enzyme complexed with the reactant chorismate or the product prephenate, no water molecule remained near the oxygen of the ligand. Calculations using the linearized Poisson-Boltzmann equation show that the effective pKa of Glu-246 is shifted from 5.8 to 8.1 as the negative charge on the ether oxygen of the TSA is changed from -0.56 electron to -0.9 electron. Altogether, these results support retention of a proton on Glu-246 to high pH and the absence of a water molecule in the catalytic steps.

Binding Sites↗
PubMed1998

Cloning and localization of RPE65 mRNA in salamander cone photoreceptor cells1.

RPE65 is a potential retinoid-processing protein expressed in the retinal pigment epithelium. Mutations in the RPE65 gene have been shown to cause certain inherited retinal dystrophies. Previous studies have shown that salamander cone photoreceptor cells have a unique retinoid processing mechanism which is distinct from that of rods. To determine whether RPE65 is expressed in photoreceptors, the RPE65 cDNA was cloned from a salamander retinal cDNA library. The deduced protein consists of 533 amino acids and is 85% identical to human and bovine RPE65. The RPE65 mRNA was detected in all of the single cone cells isolated from the salamander retina, as well as in the retinal pigment epithelium by RT-PCR, but not in the isolated rods. The RT-PCR products have been confirmed to be RPE65 by DNA sequencing. The results indicate that this potential retinoid processing protein is expressed in the cone photoreceptor cells but not in rods. Therefore, this protein may contribute to the unique retinoid processing capabilities in salamander cones.

Amino Acid Sequence↗
PubMed1998

Expression of a fusion protein of scFv-biotin mimetic peptide for immunoassay.

We constructed two fusion proteins of scFv linked to biotin mimetic sequence (BMS) via different linkers, and expressed them in the Pichia pastoris expression/secretion system. We found that both bi-functional scFv proteins exhibited their intrinsic binding activities to antigen CA125 determined in competitive radioimmunoassay experiments, but the fusion protein with a spacer between the scFv and BMS (scFv-spacer-BMS) showed higher binding activity of streptavidin than the one with c-Myc peptide as a linker.

Antibodies, Bispecific↗
PubMed1998

A physical map of 30,000 human genes.

A map of 30,181 human gene-based markers was assembled and integrated with the current genetic map by radiation hybrid mapping. The new gene map contains nearly twice as many genes as the previous release, includes most genes that encode proteins of known function, and is twofold to threefold more accurate than the previous version. A redesigned, more informative and functional World Wide Web site (www.ncbi.nlm.nih.gov/genemap) provides the mapping information and associated data and annotations. This resource constitutes an important infrastructure and tool for the study of complex genetic traits, the positional cloning of disease genes, the cross-referencing of mammalian genomes, and validated human transcribed sequences for large-scale studies of gene expression.

Animals↗