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Biomedical subjects

M Fan

Publications and source records attributed to M Fan.

At least 91 records · Page 5Linked to original sources
PubMed1998

[A study on anti-caries activity of genetic recombinant vaccine of Streptococcus lactis. II. Immunization in vein with recombinant S. lactis in pregnant rabbits].

The effects of immunization in vein with recombinant S. lactis HL107 carring the S. mutans surface protein PAc gene in pregnant rabbits were studied. The results indicated that specific anti-PAc IgG in serum and milk were obviously induced 1 week after immunization and retained at high level for several weeks. It suggests that the recombinant S. lactis HL107 possessing immunogenicity of S. mutans surface protein PAc is able to stimulate specific systemic immune response against PAc.

Animals↗
PubMed1998

[Cloning and sequence analysis of rOmpA gene fragment of spotted fever group Rickettsiae isolated in China].

Rr 190.70 p-602 n primers were used to amplify the rOmpA gene fragment of prototype strains (Rickettsia sibirica 246 strain and R. parkeri) and Chinese strains (BJ-90, Ha-91 and HLJ-054) of spotted fever group rickettsiae (SFGR). The PCR products were cloned into pGEM-T vector respectively and sequenced by Sanger's dideoxy method. The sequences of the tested strains were compared with the corresponding regions of prototype and reference strains of SFGR. The results showed that the homology of rOmpA gene fragments of prototype strains varied from 90.06%-96.62% in nucleotide and 83.05%-94.35% in putative amino acid respectively. Compared Chinese strains with prototype and reference strains of SFGR, it was found that the homology of BJ-90 strain and Ha-91 strain with R. sibirica 246 strain was the highest in nucleotide (99.06% and 98.31%, respectively) and in putative amino acid (98.87% and 96.61%, respectively), whereas HL-93 strain and HLJ-054 strain showed higher homology with R. japonica (96.62% and 95.68% in nucleotide, respectively) than others. Among all the Chinese strains, the homology between BJ-90 strain and Ha-91 strain was the highest, 99.25% in uncleotide and 97.74% in putative amino acid. The homology of nucleotide and putative amino acid between HL-93 strain and HLJ-054 strain was 98.12% and 94.92% respectively. The above results indicated that all SFGR so far isolated from different sources seem to be identical or closely related to R. sibirica, except for HL-93 and HLJ-054 strains, which could be considered as new members of SFGR.

Amino Acid Sequence↗
PubMed1997

Lymph node micrometastases from breast carcinoma: reviewing the dilemma.

BACKGROUND: The presence or absence of regional lymph node metastases has been one of the most important determining factors in recommending adjuvant chemotherapy for patients with breast carcinoma. However, because of the 15-20% failure rate at 5 years for lymph node negative patients, other tumor-related prognostic factors have gained greater significance in this decision-making process. Many investigators have reported finding micrometastases that were not detected by routine sectioning of the lymph nodes but were identified by multiple sectioning and additional staining. This review attempts to evaluate the role of occult lymph node micrometastases and their relevance to disease recurrence. METHODS: A literature search of the entire MEDLINE data base was conducted. All relevant articles were reviewed for the criteria they used to define micrometastases. The frequency of detection of micrometastases by various methodologies and the prognostic significance of such deposits were examined. RESULTS: Tumor deposits involving the lymph nodes were found to be arbitrarily categorized as either micrometastases or macrometastases, with the cutoff point ranging from 0.2-2.0 mm. The detection rate of such deposits by conventional techniques was inadequate. Serial sectioning and immunohistochemistry appeared to increase the detection rate by 9-33%. A definite survival disadvantage was noted for patients with such occult metastases. CONCLUSIONS: Current routine histologic examination of regional lymph nodes underestimates breast carcinoma metastases. Serial sectioning and immunohistochemistry increase the yield but are too labor-intensive and expensive for routine use. However, the introduction of the sentinel lymph node biopsy in lieu of axillary lymph node dissection in cases of breast carcinoma holds promise for making these methods practical and cost-effective.

Breast Neoplasms↗
PubMed1997

[Comparison between the effects of rhCNTF on sensory and motor neuron of chicken embryo].

The effects of rhCNTF on dorsal root ganglia (DRG) sensory neurons and spinal cord (SC) motor neurons of 10-day chicken embryos were observed with serum-free culture. The results indicated that rhCNTF supported the survival and differentiation of these neurons and showed certain dose-dependent manners. No effect was found at 0.5 ng/ml rhCNTF concentration, a little survival promotive effect at 1.0-1.5 ng/ml, peak effect at 4 ng/ml and no more effects from 8.0 to 100 ng/ml. The survival number of neurons on 7th day was compared, and results showed higher sensitivity of sensory neuron to CNTF shortage than that of motoneuron. This suggests that survival effect of CNTF on motoneuron is only small part of its neurotrophic effects.

Animals↗
PubMed1997

[The effects of strontium in drinking water on growth and development of rat bone].

Effects of strontium at a high level in drinking water on growth and development of rat bone were studied. The results showed that Sr2+ concentration from 5 to 500 mg/L in drinking water could increase the contents of strontium in blood serum, urine, femur, mixilla and tooth in Wistar rats exposed to Sr2+ for 12 weeks with an obvious dose-response relationship. In addition, strontium at over 50 mg/L could decrease the contents of calcium in bone, increase the contents of calcium in tooth and bone density, and decrease the levels of calcium in blood serum except female rats at the 12th week. Effects of Sr2+ on body weight, body length, AKP activity of serum, calcium content of urine and breaking load of bended femur for rats were not found. However, there are differences in the effects of strontium on growth and development of bone between male and female rats. At the 12th week the content of calcium in blood serum decreased in male rats but increased in female rats in exposed groups. At the 4th and 8th weeks, urine Hop/Cr in male rats increased but it remained normal level in female rats. Sr2+ increased the bone density of mixilla in male rats but it did not increase that of femur in female rats. It is suggested that such changes may be a result of the differences in endocritic regulation and metabolic process between two sexes.

Animals↗
PubMed1997

[Dynamic study on the mutagenic activity of organic concentration of water from one branch port of Huangpu River].

From 1991 to 1994, we studied the mutagenicity of drinking water in Shanghai by seasons by Ames test. The results indicated that the mean value of mutagenic activity of organic concentration on TA98 is 162 revertants per liter. Studies on the four branch ports of Huangpu river showed that they contributed 74% of the total mutagenicity, which accounted for the predominant fraction of the mutagenic activity of Shanghai drinking water. The mutagenicity of Hongkou branch was the highest, accounting for 1/3 of the total mutagenic activity of the 4 branches. Studies showed that the mutagenic activity of organic concentration of Hongkou branch water was declining year by year, and factors affecting the mutagenic activity were analysed.

China↗
PubMed1997

[Detection of types I, III and IV collagen in human cementum, periodontal ligament and alveolar bone].

The aim of the present study was to investigate distribution and composition of collagen Types I, III and IV in human cementum, periodontal ligament and alveolar bone with immunohistochemical localization and image analysis technique. The results showed that collagen Type I was 78.06% in periodontal ligament, 73.09% in cementum and 30.50% in alveolar bone; Type III was 11.73% in periodontal ligament and was also observed in apical cementum and bone tissue of alveolar socket; Type IV was restricted to the basement membrane of the blood vessles; Sharpey's fibers was stained by Type I and its periphery was demonstrated stronger staining by Type I and Type III as a sheath. These results provided necessary informations on healthy periodontal tissues that will be required for future studies on the effects of pathological and regenerative processes.

Alveolar Process↗
PubMed1997

[Ultrastructure of adherence of Streptococcus mutans MT8148 and its glucosyltransferase deficient mutants].

The ultrastructure of adherence of Streptococcus mutans MT8148 and its glucosyltransferase deficient mutants were compared by Scanning Electronic Microscope. Four patterns of adherence of tested strains in the presence of sucrose were observed. These results suggest that the cell-associated GTase is responsible for firm aggregation of cells. However, cell free GTase is also important in aggregation between cells.

Bacterial Adhesion↗
PubMed1997

[LIM homeobox genes family in nervous system].

Homeobox genes define a class of genes containing homeobox sequences and encoding proteins, that are identified as transcription regulator controlling cellular development and differentiation, and controlling patterns of gene expression. LIM homeobox genes contain both a homeobox and a conservative sequences (encoded LIM domain). The members of the LIM homeobox genes family which have recently been identified include lin-11, mec-3, apterous(ap), isl-1, LH-2, Rlim, lim-1, lmx-1, Xlim-1 and Xlim-3. Recent findings suggested that products expressed by LIM homeobox genes family play an important role in adjusting differentiation and developmental of the organism. The effects of LIM homeobox genes in the differentiation and development of neurons are currently attracting more and more attention.

Animals↗
PubMed1997

[Research progresses on signal transduction of neurotrophins].

Binding of neurotrophins and their receptors lead to dimerization and autophosphorylation of trks. Activated trkA initiates the Ras pathway and finally opens the transcriptions of immediate early genes and delayed response genes or participates directly in physiological responses. Target-derived neurotrophins bind to and induce phosphorylation of trk receptors at the axonal terminal. Active trk or NT-trk or other signal molecules can be retrogradely transported along the axon to transduct messages to neuronal nucleus. There are local autocrine and paracrine mechanisms besides target-derived NTs. Following nervous system injury, increased gene expressions of NTs and their receptors and increased retrograde axonal transport are helpful to survive and regenerate for injured neurons. Lacking NTs and their receptors will result in serious abnormal development of nervous system of mice.

Animals↗
PubMed1997

[The effect of chlorhexidine varnish system on Streptococcus mutans in fissure plaques].

A chlorhexidine varnish system and a controlled releasing varnish were prepared by the authors. The release rate of chlorhexidine in vitro and the effects on S. mutans and S. sanguis in vivo were determined. The results showed that the system could selectively inhibit the growth of S. mutans in fissure plaque and had no effect on S. sanguis. The period of interaction between the layer of varnish and plaque was prolonged by the control-releasing reagent. The study suggests that the chlorhexidine varnish system is effective of anticaries and can maintain microflora balance in oral bacteria.

Adolescent↗
PubMed1997

[Mineralization of human dental pulp cells in continued culture].

The purpose of this study was to understand the mineralization of human dental pulp cells in vitro. Pulp cells were isolated from human normal permanent teeth and cultured in normal tissue-culture medium. With continued culture, pulp cells formed cell nodules after 12-15 days, but no cell nodules were found from human gingiva fibroblasts. Pulp cells showed high alkaline phosphatase activity and the nodules were strongly stained by Von Kossa. Furthermore, the nodules showed high level of calcium and phosphorus by Energy-dispersive X-ray analysis and pulp cells had similar ultrastrusture with odontoblasts under TEM. The continued culture of pulp cells provides a useful system for studying differentiation and calcification of pulp tissue.

Alkaline Phosphatase↗
PubMed1997

[Bianticollagen membrane: preparation and analysis of properties].

This study was undertaken to assess the antiplaque and anticollagenase properties of bianticollagen membrane (BACM) for use in the guided tissue regeneration (GTR). First, preparing cross-linked collagen membrane (GLCM) from bone collagen by glutaraldehyde and ultraviolet irradiation. Then, the GLCM was coated with tetracycline (TC) delivery device, which is BACM. BACM's properties are as follows: under scan electron microscope (SEM), it is a three dimensional structure with small pores; the modulus of elasticity in low strain regions and swelling ratio are 20.4 g/mm2 and 0.141 respectively; immediate type and delayed type hypersensitivity are negative; BACM with TC 150 micrograms placed into pockets, the average intrasulcular TC concentration measured at the end of the 7-days is 46.76 +/- 5.69 micromol/L, which is 2 times higher than MIC of TC; the period against collagenase (100 u) digestion is over 30 days in vitro; 1 mg GLCM and BACM implanted in mice may maintain about 4 weeks and 7 weeks respectively, and BACM and GLCM placed onto patient's root surface in flap operation and taken at 7th day the bacteria on BACM are significantly less than that on GLCM under SEM. These results indicate that BACM has antiplaque and stronger antidegradation effects than GLCM.

Animals↗
PubMed1997

[Study on the vaccine against dental caries of recombinant Streptococcus lactis and artificial active immunization. V. Extraction, purification and dot blot analysis of RNA in the recombinant S. lactis].

To investigate the transcription level of the pac gene in the recombinant S. lactis, the amount of PAc-specific mRNA was measured by RNA dot blot analysis with the biotin-labeled 1.5 kb PstI fragment of the pac gene. RNA were extracted with guanidinium thiocyanate followed by centrifugation in cesium chloride solutions. These results indicated the sequence of PAc-mRNA in S. lactis HL107 or HL45 was the same as that in S. mutans Ingbritt and showed similar density photograph. The PAc-specific mRNA plated an intermediary role of protein synthesis in recombinant S. lactis and made it complete the expression of cloned pac gene.

Blotting, Northern↗
PubMed1997

[Improvement of the pre-hypertensive inherited cardiac dearangements with phenylalanine in essential hypertension].

OBJECTIVE: To assess whether phenylalanine intervention can effectively improve the pre-hypertensive inherited cardiac hypertrophy and systolic dysfunction in young offsprings of patients with essential hypertension (ER). METHODS: Ninty-six normotensive adolescents with hypertensive family history and associated with inherited cardiac hypertrophy, i.e, interventricular, septum (IVST) and (or) left ventricular post wall thickness (PWT) > or = 10.5 mm, were screened according to the normal range criteria of ultrasonic-cardiogram (UCG) obtained previously from 50 normotensive adolescents without hypertensive genetic predisposition. The UCG parameters before and after 3, 6, 9 months of observation were compared between intervention group (Phe 1 g/d 58 subjects) and placebo-control group (placebo 1 g/d, 38 subjects) in 2 separate trials by a double-blind, randomized, cross-over and comparable placebo-control design. RESULTS: The hypertrophy and dilatation of ascending aorta and left heart structure were regressed after intervention, i.g, the changes after 9 months intervention, IVST dropped from 10.9 +/- 1.2 to 9.2 +/- 0.6 mm, PWT from 9.5 +/- 1.0 to 8.6 +/- 0.6 mm, left ventricular mass index from 92 +/- 15 to 70 +/- 11 g/m2; All of the parameters reflecting the systolic function of left ventricle were improved in pooled group of 2 trials. The UCGs after placebo was fundamentally not changed except some sporadic values. The results were similar in 2 separate trials. The improvement after Phe and its return towards that of pre-intervention after stope were remarked at 6 months. CONCLUSION: The inherited cardiac dearrangement seen in adolescents with hypertensive genetic predisposition can be assumed to be the pre-hypertensive changes of EH. It can be reversed by phenylalanine--a natural and essential amino-acid.

Adolescent↗
PubMed1997

[Hemorheological disorders in patients with sudden deafness].

Fourteen hemorheological and related parameters of blood samples derived from 59 patients with sudden deafness were observed and were compared with those of blood samples got from 512 healthy persons. The ratio viscosity of whole blood (6.50 +/- 1.07), reduced viscosity of whole blood (12.37 +/- 1.80), and plasma viscosity (1.84 +/- 0.14) in male patients were significantly higher than those (6.05 +/- 0.63, 11.06 +/- 1.04, and 1.70 +/- 0.07, respectively) in male controls. The reduced viscosity of whole blood (16.62 +/- 3.87) and plasma viscosity (1.92 +/- 0.13) in female patients were also significantly higher than those (14.40 +/- 2.27 and 1.72 +/- 0.06, respectively) in female controls. The findings above suggest that there is an intimate relationship between the microcirculationary disorder resulting from hemorheological changes and the onset of sudden deafness. The parameters related to plasma viscosity revealed that there were higher concentrations of plasma fibrinogen and triglyceride in male patients than those in male controls, while the concentrations of plasma cholesterol and triglyceride were higher in female patients than in female controls. These results indicate that the factors which induce the change of plasma viscosity in male patients could not be the same as those in female patients. Thus, in the process of treating sudden deafness, besides the use of common devices such as reducing blood viscosity and improving microcirculation, some other special steps based on the hemorheological parameters derived from different sexes or individuals, should also be considered.

Adolescent↗