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Biomedical subjects

S Ma

Publications and source records attributed to S Ma.

At least 145 records · Page 8Linked to original sources
PubMed1996

Measurement of radiation-induced DNA double-strand breaks in human diploid fibroblasts from keloid and normal skin by single-cell gel electrophoresis.

Cell culture experiments recently have shown that different populations of fibroblasts may exist in keloid patients. Moreover, several studies have strongly suggested heterogeneity in cell response of skin fibroblasts in the same individual. The purpose of this study was to evaluate the radiation sensitivity of skin fibroblasts from keloid and normal skin. Single-cell gel electrophoresis was employed in detecting amounts of DNA double-strand breaks generated in individual fibroblasts primarily cultured from normal skin and from keloid tissue after various doses of gamma-irradiation (0, 25, 50, and 100 Gy aerobically) from a 137Cs radiation generator. For the repair study, cells were incubated at 37 degrees C for 0 and 15 minutes and 1 and 2 hours after irradiation. Following neutral lysis and electrophoresis, DNA double-strand breaks were then detected by propidium iodide staining and determined by fluorescence microscope and quantitative image analysis. No significant difference in the extent of DNA double strand breaks in fibroblasts from normal skin or keloid after various doses of irradiation was observed. However, the residual DNA double-strand breaks remaining after various periods of incubation were demonstrated to be significantly increased in fibroblasts from keloid (p < 0.01). In conclusion, different repair capacities were found in fibroblasts from normal skin and keloid scar; this finding may play a role in the treatment of the disease entity.

Cells, Cultured↗
PubMed1996

Anti-inflammatory activities of 70% methanolic extract from Cinnamomi Cortex.

The effects of 70% methanolic extract (CC-ext) from Cinnamomi Cortex on acute and chronic inflammation were investigated. CC-ext inhibited the rise in vascular permeability induced by acetic acid and the increase of paw edema induced by carrageenin in mice. It was ineffective on edema derived by histamine or bradykinin, and exhibited only weak inhibitory effect on the edema derived by serotonin. CC-ext also showed inhibitory effects on the prekallikrein enzyme activity and ear edema induced by arachidonic acid. It also had an inhibitory effect on cotton pellet-induced granuloma but showed no atrophying action against the adrenal or thymus glands. Little effect was shown on secondary lesions in the development of adjuvant-induced arthritis (the arthritis reappeared from 11 to 27 d after injection of the adjuvant). These results suggest that some active component having an inhibitory effect on acute inflammation is contained in Cinnamomi Cortex.

Animals↗
PubMed1996

An improved technique for molecular cytogenetic analysis of human preimplantation embryos with fluorescence in situ hybridization.

OBJECTIVE: To develop a method for the cytogenetic evaluation of preimplantation embryos using nonradioactive centromeric probes for chromosomes 1, 16 and X. STUDY DESIGN: The embryos used for this study were either fragmented or polyploid embryos rejected from an in vitro fertilization program. Prior to in situ hybridization, the embryos were treated with 0.5% protease. After application of gradual fixation, conventional hybridization protocol was followed. RESULTS: Ten of 11 embryos showed hybridization signals suggesting that the success rate of in situ hybridization of human embryos is improved when a modified method of digesting the zona pellucida and gradual fixation with removal of the cytoplasm are used. CONCLUSION: The method described in this study demonstrates that the zona pellucida is the key to successful in situ hybridization of whole human embryos. When the zona pellucida is removed, penetration by a probe becomes possible.

Chromosome Aberrations↗
PubMed1996

[Acceleration of hematopoietic reconstitution in mice transplanted with syngeneic bone marrow cells by IL-6 gene therapy].

In the present study, the potential of fibroblast-mediated IL-6 gene therapy for accelerating hematopoietic reconstitution after syngeneic bone marrow transplantation (BMT) in BALB/c mice subjected to total body irradiation at a dose of 7 Gy was investigated. We observed that not only recovery of platelets, WBCs, CFU-GM or CFU-MK in bone marrow in mice treated with IL-6 gene therapy in combination with transplantation of 10(7) syngeneic bone marrow cells was faster than that in mice treated with IL-6 gene therapy in combination with transplantation of 10(6) or 10(5) syngeneic bone marrow cells, but also the number of CFU-S or survival rate in mice treated with IL-6 gene therapy in combination with transplantation of 10(7) syngeneic bone marrow cells was significantly higher. Nevertheless, the number of platelets, WBCs, CFU-GM or CFU-MK in bone marrow, CFU-S and survival rate in mice treated with IL-6 gene therapy in combination with transplantation of syngeneic bone marrow cells were elevated more significantly than that in mice transplanted with syngeneic bone marrow cells alone. These data demonstrated that IL-6 gene therapy could markedly augment hematopoietic reconstitution after syngeneic bone marrow transplantation and the more bone marrow cells transplanted, the better was the effect.

3T3 Cells↗
PubMed1996

[Ovarian metastasis in uterine cervical cancer: analysis of 17 cases].

OBJECTIVE: To investigate the incidence of ovarian metastasis in cervical cancer, especially in early FIGO stages. METHODS: Seventeen cervical cancer patients with ovarian metastasis treated at Cancer Hospital, Chinese Academy of Medical Sciences from 1958 to 1994 were retrospectively analysed. The diagnoses of all patients were confirmed by operations and pathologic examinations. RESULTS: The incidence of ovarian metastasis in cervical cancer was 0.07% in squamous cell carcinoma and 1.81% in adenocarcinoma (P < 0.05). In early stages (stage l-I), the incidence of ovarian metastasis in adenocarcinoma was higher than that in squamous cell carcinoma (2.2% VS 0.08%, P < 0.05). In patients treated by surgery, the rate of ovarian metastasis in adenocarcinoma was also higher than that in squamous cell carcinoma (7.8% VS 1.6%, P < 0.05). 10 of the 17 cases had macroscopic metastasis and 7 had microscopic metastasis. 11 patients (58.8%) were with bilateral ovarian involvement. Uterine corpus invasion and retroperitoneal lymph node involvements were high risk factors for ovarian metastasis in cervical cancer. The prognosis of cervical cancer patients with ovarian metastasis was poor, the 5-year survival rate in this study being only 17.6%. CONCLUSIONS: Patients with cervical cancer are threatened with the risk of ovarian metastasis, especially in adenocarcinoma. Conservative treatment of the cervical cancer with reservation of the ovary should be further investigated.

Adenocarcinoma↗
PubMed1996

[Therapeutic effect of vaccinia virus secreting granulocyte-macrophage colony-stimulating factor on pulmonary metastatic melanoma].

A recombinant vaccinia virus containing and expressing the gene of murine granulocyte-macrophage colony-stimulating factor (VVGM-CSF) was tested for its antitumor activity. Murine pulmonary metastasis was established by injecting 2 x 10(5) B16F10 melanoma cells into tail vein of C57BL/6 mouse. Three days after B16F10 inoculation, VVGM-CSF or VVTK, a thymidine kinase gene deficient vaccinia virus, was injected intraperitoneally twice weekly for 2 weeks. Two weeks later mice were sacrificed and pulmonary metastasis foci counted. The results showed that VVGM-CSF treatment significantly decreased the number of pulmonary metastasis and prolonged the survival time of tumor-bearing mice (P < 0.01). Cytotoxic and phagocytic activities of peritoneal macrophages were found to be markedly elevated in mice treated with VVGM-CSF. Nitric oxide released from macrophages was also found to be increased. Based on these data, together with our previous results, we may speculate that continuous secretion of GM-CSF and activation of macrophages might partially explain the antitumor effects of VVGM-CSF.

Animals↗
PubMed1996

Antenatal diagnosis and management of Dandy-Walker syndrome.

The Dandy-Walker syndrome (DWS) can be accurately diagnosed in utero by sonographic demonstration of characteristic morphologic changes of the fetus, which includes hydrocephalus, incomplete cerebellar vermis and a posterior fossa cyst. We present a case of Dandy-Walker syndrome diagnosed antenatally. The associated anomalies are reviewed, and the value of antenatal diagnosis is discussed.

Adult↗
PubMed1996

[Epicanthoplasty during double-fold eyelid operation].

OBJECTIVE: In order to achieve an artistic epicanthoplasty and gain an ideal eyelid double-fold parallel to the lid margin. METHODS: Various epicanthoplasty procedures were performed on 183 patients. Combining Fox's plastic operation for correcting upper lid type epicanthus and "L" form removal of skin for correcting lower lid type epicanthus, we put forward three kinds of methods available for epicanthoplasty. According to the degree of seriousness of upper lid type epicanthus, the patients who had a strong desire to receive treatment or improve their looks underwent different operative procedures. The skin resection in 38 cases was of shuttle-form and in 120 cases, of cuneiform: low level "Z"-plasty was performed on 25 cases. RESULTS: Satisfactory cosmetic results were obtained in 183 cases. CONCLUSION: These methods of plastic surgery can achieve artistic epicanthoplasty in double-fold eyelid operation.

Adolescent↗
PubMed1996

[Clinical study of imposed work of breathing caused by the breathing apparatus].

OBJECTIVE: The imposed work of breathing caused by the breathing apparatus (endotracheal tube, breathing circuit tubing, and ventilator's valves) may increase patient's work of breathing. To evaluate the imposed work may be useful to determine weaning. METHODS: Work of breathing was observed by Bicore CP-100 breathing monitor at different levels pressure support (PS), T piece and after extubation, and the PS level to compensate imposed work of breathing was computed. RESULTS: When PS level decreased, patient's work of breathing increased significantly. At PS O kPa, the patient's work of breathing increased 57%, which was caused by imposed work of apparatus. Because of the resistance of endotracheal tube, the patient's work of breathing increased 41% at T piece. The PS level that compensated for the imposed work was 0.7 kPa. CONCLUSIONS: When PS level was too low or T piece was applied, the imposed work of breathing caused by apparatus could markedly increase patient's work of breathing.

Adult↗
PubMed1996

[Pharmacognostical study on the Chinese drug biejia].

The Chinese drug Biejia is taken from a variety of animals. In this paper, 3 kinds of Biejia from different genera have been studied in their pharmacognostical characteristics and microproperties. A key has been complied based on the experimental results.

Animals↗
PubMed1995

Capillary zone electrophoresis at subzero temperatures. I. Separation of the cis and trans conformers of small peptides.

The cis-trans conformers of two dipeptides, Phe-Pro and Leu-Pro, and two opioid heptapeptides containing one or two proline residues were separated by capillary zone electrophoresis (CZE) in borate buffer at low temperatures down to -17 degrees C. At temperatures near ambient, the relaxation time of the cis-trans isomerization is on the time-scale of minutes for the dipeptides and thus commensurate with the migration times in CZE under usual operating conditions. The conformers of both dipeptides could be separated with baseline resolution below 10 degrees C in neat aqueous 100 mM sodium borate (pH 8.4). The conformer peaks on the electropherograms were identified by using authentic samples of the cis and trans forms of Phe-Pro and Leu-Pro that were obtained by reversed-phase HPLC at 0 degree C, validated by NMR spectroscopy and stored in liquid nitrogen. The interplay of the electrophoretic migration and on-column isomerization reaction in CZE of Phe-Pro under various conditions was analyzed in the light of the Damköhler number (Da). The results showed that besides employing low temperature increasing the voltage and/or decreasing the capillary length also reduce the magnitude of Da to bring about the separation of interconverting species. In this work the use of low temperature in this work was preferred due to the experimental simplicity. The separation of cis-trans conformers of two opioid heptapeptides was carried out by CZE at subzero temperatures with aqueous sodium borate containing 23% (v/v) glycerol at pH* 11.3 as measured with a glass electrode. The two conformers of Tyr-Pro-Phe-Asp-Val-Val-Gly-NH2 were baseline separated at -12 degrees C and the four conformers of Tyr-Pro-Phe-Gly-Tyr-Pro-Ser-NH2 due to the presence of two peptidyl-proline bonds in the molecule, were also resolved at -12 degrees C. From the electrophoretic mobilities, the hydrodynamic radii of the cis-trans conformers of the dipeptides Phe-Pro and Leu-Pro were estimated. In both cases, the trans isomers had 1.3 times greater Stokes radii than the cis conformers. This agrees with the observed migration order and molecular modeling results. The hydrodynamic radii of the Phe-Pro conformers were smaller than those of the Leu-Pro isomers despite the lower molecular mass of the latter. The results demonstrate that CZE is suitable for measuring certain molecular properties and suggest that the methods introduced here are applicable to the study of other systems of interconverting conformers.

Amino Acid Sequence↗
PubMed1995

In vivo and in vitro studies on the neurotoxic potential of 6-hydroxydopamine analogs.

In an attempt to determine which physical and biological properties could best be correlated with neurotoxic potential, seven analogs of 1-(2,4,5-trihydroxyphenyl)-2-aminoethane (1), better known as 6-hydroxydopamine, were synthesized and compared to 1 in a variety of ways both in vivo and in vitro. The analogs, in combination with the standard 1, include all eight of the 2,4,5-trisubstituted-phenyl derivatives of phenethylamine and alpha-methylphenethylamine in which the substitution is of the trihydroxy or aminodihydroxy form. Low (60 nmol) and high (300 nmol) intracerebroventricular doses of all analogs produced long-term (7 day) reduction of mouse whole brain norepinephrine (NE) and lesser depletions of dopamine (DA), and effects on serotonin were varied. The analog 1-(5-amino-2,4-dihydroxyphenyl)-2-aminopropane (8) was both more complete and more selective than the standard 1 in depleting NE. Using a histofluorometric glyoxylic acid method and Fink-Heimer silver degeneration stain, it was determined that overt neural degeneration was produced by 8. In vitro, the ease of oxidation of the eight analogs was found to be represented by a formal potential range of -130 to -212 mV vs SCE. However, there was no obvious relationship between ease of oxidation and the extent of monoamine depletion from mouse brain. Using kinetic analysis of synaptosomal accumulation of [3H]NE and [3H]DA, it was found that the standard 1 is more potent in its interaction with the DA uptake site (Ki = 12 +/- 0 microM) than the NE uptake site (Ki = 51 +/- 1 microM). A correlation analysis was used to determine that differences in NE and DA depletion by each analog could not be explained by differences in potency for in vitro uptake blockade. However, there was a correlation between the Ki for [3H]NE uptake blockade and the EC50 for synaptosomal release of preloaded [3H]NE for the eight analogs (R2 = 0.96; for log:log plot, R2 = 0.54), indicating that the results for these two in vitro tests both reflect interaction with the same NE neuronal membrane transport site. A similar correlation between Ki and EC50 was shown for all eight analogs using [3H]DA (R2 = 0.92; for log:log plot, R2 = 0.52), indicating interaction with the same DA neuronal membrane transport site. These findings demonstrate that there is no single property that can account for selectivity of action and/or potency of catecholamine neurotoxins related to 6-hydroxydopamine.

Animals↗
PubMed1995

Capillary electrophoresis of S. nuclease mutants.

The electrophoretic migration behavior of 12 S. nuclease variants from Staphylococcus aureus with small but well defined structural differences from site directed mutation was investigated in free solution capillary electrophoresis at pH 2.8 to 9.5. The nucleases are basic proteins; the pI and the M(r) of the wild type are 10.3 and 16.811 kd, respectively. With specially selected oligoamino buffers and with an inert, hydrophilic wall coating in 75 microns I.D. quartz capillary tubes, most of the proteins could be separated by CZE without interference by wall adsorption even at pH 9.5 where the selectivity was the highest. At pH 2.8, 4.1 and 7.0, S. nucleases are known to be in the random coil, "swollen" and the tight native state. Assuming that in a given state, i.e., at a certain pH, the molecular radii of the nucleases are the same, their hydrodynamic radii were calculated from their pertinent electrophoretic mobilities. The respective radii of 50.1, 26.8, and 25.0 Angstrum thus obtained agreed very well with the corresponding radii of gyration obtained from X-ray scattering. In fact, from the electrophoretic mobilities at pH 9.5, the existence of a hitherto unknown swollen basic state of the nuclease having a hydrodynamic radius of 30.5 Angstrum was postulated. In addition, a method was described to evaluate the valence of the protein at different pH from their pertinent electrophoretic mobilities. A general advantage of this method is that only the differences between the valences of the mutants and the wild type are needed; and for none of the proteins is required the knowledge of the actual valence. The results of the methods allowed the construction of a pH profile of the protein's valence. For the wild type, this profile was compared to the H+ titration curve and the agreement was excellent. Both methods employed some novel structure-electrophoretic mobility relationships and the predicted protein properties compared remarkably well to the values obtained by exoelectrophoretic methods such as pH titration and X-ray scattering. Surprisingly, certain S. nucleases having the same valence could also be readily separated by CZE in some cases under the same conditions used for the others. Close examination of appropriate X-ray crystallography and/or NMR data indicated subtle differences in the molecular structure of these proteins that could be responsible for slight alteration in their hydrodynamic radii.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1995

Charge and size effects in the capillary zone electrophoresis of nuclease A and its variants.

The migration behavior of nuclease A from Staphylococcus aureus and 11 of its variants in capillary zone electrophoresis (CZE) was investigated in the light of their three-dimensional structure known from X-ray crystallography and nuclear magnetic resonance (NMR) measurements. Nuclease A (molecular mass 16.8 kDa, pKa 10.3) and the variants differ only in a single amino acid residue and have a very similar crystal structure. With the use of coated quartz capillaries and suitable buffers, the protein migration was investigated at pH from 2.8 to 9.5 without interference by wall adsorption. Although the selectivity of the electrophoretic system for the proteins was mainly determined by their charge differences, certain variants having the same net charge could also be readily separated under nondenaturing conditions. For instance, the mobility of variant K116A was sufficiently higher than that of K116G so that they could be separated by CZE. The structures of both variants are the same except for the solvent-exposed loop containing residue 116. For this reason, the difference in electrophoretic mobilities can be attributed to the fact that in K116G the backbone of the 112 to 117 amino acids protrudes slightly from the protein, with a concomitant increase in the hydrodynamic radius with respect to that of K116A. Consequently, K116G shows a smaller mobility than K116A due to its larger hydrodynamic radius despite its smaller molecular mass. The interpretation of the experimentally measured mobilities of such closely related proteins therefore requires not only consideration of their electrostatic charge but also the fine details of their molecular structures.

Amino Acid Sequence↗
PubMed1995

Isolation of predominantly submicron-sized UHMWPE wear particles from periprosthetic tissues.

A method of tissue digestion using sodium hydroxide was applied to the isolation and recovery of ultra-high-molecular-weight polyethylene (UHMWPE) particles from tissues around failed total hip replacements. Density gradient ultracentrifugation of the digested tissues was performed to separate the UHMWPE from cell debris and other particulates. Fourier transform infrared spectroscopy and differential scanning calorimetry (DSC) verified that the recovered particles were UHMWPE. When viewed by scanning electron microscopy, individual particles were clearly observed and were either rounded or elongated. The majority were submicron in size. The application of this method to the study of particles from periprosthetic tissues may elucidate aspects of biomaterial particle size and shape that are important to the biologic response to, and clinical outcome of, total joint replacement.

Calorimetry, Differential Scanning↗
PubMed1995

Influence of power tool-related parameters on the response of finger flexor muscles.

Surface electromyography (EMG) and statistical analysis techniques were applied to investigate the response of finger flexor muscles to hand-transmitted vibration in all the three orthogonal directions. The trends in measured data were examined to derive the influence of variations in the tool-related parameters. Single-factor and multi-factor statistical analyses were performed to establish the significance of influence of different individual and coupled power tool-related parameters. The analysis of variance (ANOVA) results indicated that the vibration direction, acceleration and grip force influence the EMG of finger flexor muscles in a significant manner (P < 0.001), while the effect of vibration frequency was observed to be insignificant (P > 0.9). The electrical activity measured under different vibratory test conditions was observed to be 1.5-6.0 times higher than that measured under the static loads. The increase in electrical activity of the finger flexor muscles with an increase in the grip force was observed to be most significant under static as well as dynamic loading conditions.

Analysis of Variance↗
PubMed1995

High-resolution proton nuclear magnetic resonance studies of urine from asphyxiated newborn infants.

High-resolution proton nuclear magnetic resonance spectroscopy was used to study human urine obtained from 10 normal babies and twenty babies with various degrees of neonatal asphyxia, respiratory distress syndrome (RDS), and meconium aspiration syndrome (MAS). All sick babies showed different degrees of oxygen deficiency, indicated by an obvious increase of the lactate signal level in the urine spectra. Changes in the concentration of other urinary metabolites produced from the citric acid cycle were also observed. In extremely serious cases, the signals of some of the major components, including citrate, alpha-ketoglutarate, and succinate, simply disappeared. The spectra of urine, serum, and CSF of an infant suffering from SIDS showed common characteristics of the metabolites.

Asphyxia Neonatorum↗