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Biomedical subjects

S Song

Publications and source records attributed to S Song.

At least 217 records · Page 12Linked to original sources
PubMed1995

A multicentred phase III comparative clinical trial of Mesigyna, Cyclofem and Injectable No. 1 given by intramuscular injection to Chinese women. II. The comparison of bleeding patterns.

Between 1988 and 1992, a randomized phase III clinical trial was conducted in China to compare three monthly injectable contraceptives: Mesigyna, Cyclofem and Injectable No. 1. This paper presents a detailed analysis of the menstrual diaries provided by 5098 (89%) of the subjects. In total, 902, 903 and 913 diaries were analyzed to compare bleeding patterns induced by Mesigyna, Cyclofem and Injectable No. 1. The first withdrawal bleeding usually occurs 14-20 days after the first injection for all three of these preparations. Thereafter, 50% of Mesigyna users had precisely 3 bleeding/spotting episodes every 90 days, 50% of Cyclofem users had 2-3 and 50% of Injectable No. 1 users had 3-4 episodes every 90 days. Relative to users of Mesigyna or Cyclofem, Injectable No. 1 users had 2-3 more bleeding/spotting days, and a shorter length of bleeding/spotting-free intervals in each period. 63.7%, 41.4% and 60.6% of subjects using Mesigyna, Cyclofem and Injectable No. 1, respectively, had bleeding patterns similar to their untreated patterns in the first 90-day period. The percentages increased to 82.2% 67.8% and 75.0% in the fourth 90-day period. A total of 1815 diaries for Mesigyna and 1802 for Cyclofem were analyzed for more in depth comparison of these two methods. The number of bleeding/spotting days over four periods showed little difference between the two group, but there were more spotting days and there was greater individual variability among Cyclofem users.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

High grade prostatic intraepithelial neoplasia in prostates removed following irradiation failure in the treatment of prostatic adenocarcinoma.

Prostatic Intraepithelial Neoplasia (PIN) is widely considered to be a precursor lesion for adenocarcinoma of the prostate. No information is available, however, on the sensitivity of PIN to irradiation or the distribution of residual PIN after radiotherapy. We studied a series of forty-six totally embedded, whole mounted, serially sectioned prostates removed by salvage radical retropubic prostatectomy following irradiation failure in which no hormonal therapy/ablation had been undertaken. The mean age of patients was 65 (56-74) years, the mean dose of radiotherapy was 7,266 (6,000-9,000) cGy (15 external beam, 27 external beam plus iridium or gold seed, 3 iodine, and 1 unknown) and the mean interval for irradiation therapy to prostatectomy was 60 (16-145) months. Thirty-two (70%) of the patients had high grade PIN within the prostatectomy specimen. The pattern of PIN was recorded as described by Bostwick and co workers. The frequency of the different patterns per positive case paralleled in rank those in Bostwick's series of non-irradiated prostates, with the most common to least common per patient being: tufting (78.1%), micropapillary (59.3%), cribriform (34.4%) and flat (15.6%). However, the mean number of foci of PIN per prostate was less than in Bostwick's series (7.1 foci vs. 17 foci). There was no statistically significant difference between groups with or without high grade PIN with regard to various clinical factors (last preoperative serum PSA, age, dose of radiotherapy, interval from irradiation therapy to prostatectomy, Kaplan-Meier survival), or pathologic factors (presence of confined tumor, extracapsular extension, positive surgical margins, seminal vesicle invasion, or positive lymph nodes on permanent sections). We conclude that high grade PIN is common in the prostates of patients who have failed irradiation therapy and that, theoretically, not all recurrent tumors derive from regrowth of the initial, incompletely eradicated tumor. However, because there was no significant difference between the two groups with regard to the clinical and pathologic parameters listed, we consider it likely that most recurrent tumors derive from the initial incompletely eradicated tumor.

Adenocarcinoma↗
PubMed1995

[Clinical trial of high-dose medroxyprogesterone acetate in advanced breast cancer].

Sixty-two evaluable patients with advanced breast cancer were treated with medroxyprogesterone acetate (Farlutal. Erba) 500mg orally twice or three times a day. After thirty days, one patient had a complete response (1.6%), 33 patients had partial response (53.2%). 11 had stable disease (17.7%), and 17 progressive disease (27.4%). The response rates of bone, lung and chest wall metastasis were higher. And the older patients showed a better response than the younger. The response did not show significant correlation with KPS, menopausal status, disease-free intervals after operation, numbers of metastases and the dose of medroxyprogesterone acetate. The response rate in ER positive patients was higher than the ER negative, but the difference was not statistically different. The side effects of high-dose medroxyprogesterone acetate were well tolerated and the most common ones were weight gain and excessive perspiration.

Adult↗
PubMed1995

[Evaluation of chemosensitivities of human breast cancers by primary culture assay in vitro].

Chemosensitivities of 32 human breast cancer to 6 antitumor drugs were assayed in vitro using MTT colorimetric method. The results showed that the chemosensitivity of primary breast cancer cultures varied remarkably from one patient, and from one drug, to another with hundred-to thousand-fold differences. The distribution of 50% inhibition concentration (IC50) was significantly deviated from normal distribution (P < 0.0001), and the drug sensitivity could be divided into four different catagories by means of percentile method. Preliminary results showed that the in vitro chemosensitivities of different antitumor drugs were consistent with the clinical therapeutic responses It seems that the herein reported assay might be useful on an individual basis to optimize chemotherapy of human breast cancer.

Antineoplastic Agents↗
PubMed1995

[Operative management of retroperitoneal tumors involving major blood vessels: a report of 20 cases].

We report the experience of operative management in 20 patients with retroperitoneal tumors with major adjacent blood vessels involved, including portal vein inferior vena cava, abdominal aorta, iliac and renal vessels, and superior mesenteric vein. The diagnosis, preoperative preparation, intraoperative management and the postoperative complications were discussed. We emphasize the importance of radical resection of the tumors involving major blood vessels and vascular reconstruction.

Adult↗
PubMed1995

[Homology of the recombinant DNA of plasmid pDJH2 with the recombinant DNA probe of L. alstoni and analysis of its expression in Escherichia coli].

Dig-labeled recombinant DNA probe of L. alstoni which contains the entire structural OmpL1 gene was hybridized with the recombinant DNA of the plasmid named pDJH2 of the gene library of L. interrogans serovar lai strain 017. The result showed a high degree of homology among them; expression of recombinant DNA of pDJH2 was achieved by beta-D-galactosidase (IPTG) induction in E. coli. The molecular weight of this product is 68kd. Then they were treated with proteinase K and subjected to SDS-PAGE. The results showed it is a protein in nature. Using the specific monoclonal antibody E4B7D5 on immunoblotting and specific polyclonal antibody on dot-ELISA assay, we investigated the immune reaction and noticed that protein 68kd might be an antigen in character. E. coli which contains the recombinant plasmid pDJH2 were injected into BALB/c mice. Then the mice were challenged by leptospires of the strong virulence strain 017, but all the infected mice survived. In this paper, we first report the expression of recombinant DNA of L. interrogans serovar lai strain 017 in E. coli when injected with IPTG, and immunoprotection of BALB/c mice which were injected with the expression against the infection of L. interrogans serovar lai strain 017. pDJH2 may be the first recombinant for which the gene has been cloned and its expression product 68kd may be the immunoprotective antigens.

Animals↗
PubMed1995

Application of fluorescent dUTP on PCR and automated PCR product detection by using internal lane size standard.

A convenient, simple, cost effective and efficient fluorescent PCR labeling for automated detection was developed by using fluorescent deoxyuridine triphosphate-(F)dUTP without changing any PCR reaction parameters. Multiple fluorescent (F)dUTPs in a broad range of concentration were tested on PCR reaction and then titration tests for optimum sample loading amount with automated detection were done by using Genescan 672 software on ABI 373A DNA sequencer. PCR product were automaticaly detected although the sensitivity of each color was different. Colors of (F)dUTP and (F)dUTP/dTTP ratio showed a significant influence on the incorpration of (F)dUTP in PCR reaction, so consequently the ratio gave a great impact on the PCR product detection results. To much incorpration of (F)dUTP changed the PCR fragment mobility and also sizing value. The application of (F)dUTP should have a great potential on linkage studies, mapping with microsatellite and mutation detection.

Color↗
PubMed1994

UV resonance Raman and excited-state relaxation rate studies of hemoglobin.

We have measured the UV resonance Raman (UVRR) spectra of human methemoglobin fluoride (metHbF) and examined the Raman saturation behavior of the metHbF trytophyl (Trp) and tyrosyl (Tyr) residues. Our high-quality UVRR spectra devoid of Raman saturation with 229- and 238.3-nm CW laser excitation allow us to determine small changes in Trp and Tyr residue Raman band frequencies and intensities caused by the hemoglobin R-T quaternary structural change induced by the allosteric effector inositol hexaphosphate. At 238.3-nm excitation, we observe a ca. 15 and 8% intensity increase for the Trp and Tyr bands, respectively, upon the R-T transition. In contrast, a small intensity decrease is observed with 225-nm excitation. These intensity alterations result from Trp and Tyr absorption and Raman excitation profile red-shifts which correlate with a strong 231.5-nm R-T absorption spectral change. These absorption and Raman excitation profile red-shifts and our model compound absorption studies together suggest a T-state increase in the hydrogen bond donation of the Trp-beta(2)37 and Tyr-alpha(1)42 residues at the alpha 1 beta 2 subunit interface. The Tyr-alpha 42 residue appears to be a hydrogen bond donor, rather than an acceptor. We determined the electronic excited-state relaxation rates of the Trp and Tyr residues in hemoglobin by using Raman saturation spectroscopy with 225-nm pulsed laser excitation. The observed average excited-state relaxation rate of the Trp residues is ca. 1/120 ps and is independent of the quaternary structure. This rate is slower that that observed for Trp residues of horse myoglobin. The average excited-state relaxation rate of the Tyr residues is ca. 1/60 ps for both the R and T quaternary forms. These are the first Tyr relaxation rates measured for any heme protein.

Amino Acid Sequence↗
PubMed1994

Conformation of ATP and ADP bound to N10-formyltetrahydrofolate synthetase determined by TRNOE NMR spectroscopy.

ATP and ADP bind to N10-CHO-H4folate synthetase from Clostridium cylindrosporum at four identical sites. Although both ADP and ATP bind to the enzyme with essentially the same Ka values as the Mg2+.nucleotide complexes, only the Mg2+.nucleotides are kinetically active. Using transferred nuclear Overhauser effect (TRNOE) NMR spectroscopy, we have measured the time-dependent NOE buildup rates of selected protons in ADP and ATP bound to N10-CHO-H4folate synthetase after preirradiating protons H1', H2', H3', and H4'. The results were used to calculate interproton distances. In order to define the conformations of ADP and ATP bound to the enzyme, we used the TRNOE distance constraints in a distance geometry algorithm. The results of the distance geometry calculations suggest that, within experimental error, the conformations of both ADP and ATP (with or without Mg2+) have an average glycosidic torsion angle X (O4'-C1'-N9-C8) of 100 degrees +/- 20 degrees and a sugar pucker angle psi' (C5'-C4'-C3'-O3') of 85 degrees +/- 5 degrees. These values are consistent with a nucleotide structure generated by computer modeling after energy minimization, which has X = 90 degrees +/- 6 degrees and psi' = 81 degrees, indicating a high-anti and C3'-endo conformation.

Adenosine Diphosphate↗
PubMed1994

A new method for determining dose rate distribution from radioimmuno-therapy using radiochromic media.

PURPOSE: To describe and evaluate a new, simple, inexpensive method for directly measuring the radiation dose and its spatial distribution generated from explanted tissues of animals previously injected with radiolabeled immunoconjugates or other agents. METHODS AND MATERIALS: This technique uses the newly developed radiochromic dye medium (Gafchromic) which responds reproducibly for therapeutic dose exposures, has high spatial resolution, does not require film processing, and is relatively insensitive to ambient light. We have evaluated the dose distribution from LS174T tumors and selected normal tissues in nude mice previously injected with 90Y labeled anti-carcinoembrionic antigen antibodies. Individual tissues from sacrificed animals are halved and the flat section of the tissue is placed onto the dosimetry media and then frozen. The dosimetry medium is exposed to beta and Bremsstrahlung radiation originating from the frozen tissues. The relative darkening of the dosimetry medium depends on the dose deposited in the film. The dosimetry medium is scanned with a commercial flatbed scanner and the image intensity is digitally stored and quantitatively analyzed. Isodose curves are generated and compared to the actual tissue outline. RESULTS: The absorbed dose distribution due to 90Y exposure show only slight gradients in the interior of the tissue, with a markedly decreasing dose near the edges of the tissue. In addition, the isodose curves follow the tissue outline except in regions having radii of curvature smaller than the range of the beta-particle (R90 = 5 mm). These results suggest that the shape of the tumor, and its curvature, are important in determining the minimum dose delivered to the tumor by radiation from 90Y monoclonal antibodies, and hence in evaluating the tumor response to the radiation. The dose and spatial dose distribution were calculated assuming that the total 90Y activity is distributed uniformly throughout a half ellipsoid. The calculated spatial dose distributions for the half ellipsoids were similar to those observed from the dosimetry media that had been exposed to radioactivity contained in the tumors. CONCLUSION: This method provides direct dose evaluation without elaborate summary calculations based on activity measurements from serial slices. The measured radiation dose actually indicates the dose rate at the time of animal sacrifice. Quantitative analysis of radiation emitted from the tissues is relatively fast, making it feasible to examine a number of tissues under a variety of conditions.

Animals↗
PubMed1994

252Cf-plasma desorption mass spectrometry. II--A perspective of new directions.

The 252Cf-PDMS method is a 'mature' technique, having survived 20 years of research, development and application. Recent advances in the application of the method have led to the use of the technique in clinical quantitation studies, the development of a microscopic method for measuring chemical homogeneity, in situ applications where serial modifications can be made and studied in a sequential fashion and the utilization of the primary fragmentation patterns to correlate with primary structure. Future directions in research, development and application will focus more attention on the chemistry of the 252Cf-PDMS process and the understanding and control of gas-phase reactions that occur in the ejection plume. Predictions are that the application of the in situ modification technique could lead to a new approach to pharmacokinetic studies as well as cell surface interactions where 252Cf-PDMS is effectively used to expand the capabilities of in vitro studies of biological processes.

Californium↗
PubMed1994

Quantifying MRI geometric distortion in tissue.

We present a method to quantify the MR field inhomogeneity geometric distortion to subpixel accuracy without using objects of known dimensions and without using an external standard such as CT. Our method may be used to quantify the geometric accuracy of MR images of anatomical structures of unknown geometry and also to test any geometry correction scheme. We have quantified the distortion in a tissue phantom and found the largest error to be approximately 2.8 pixels (1.8 mm) for Bo = 1.5 T, G = 3.13 mT/m and FOV = 160 x 160 x 70.7 mm3. We also found that our previously published correction technique reduced the largest error to 0.3 pixels (mu = 0.02 and sigma = 0.07 pixels).

Image Processing, Computer-Assisted↗
PubMed1994

Population and employment densities: structure and change.

"We examine spatial patterns and their changes during the 1970s for the Los Angeles region, by estimating monocentric and polycentric density functions for employment and population. Downtown Los Angeles is clearly identified as the statistical monocentric center of the region, and it is the most consistently strong center in the polycentric patterns. Polycentric models fit statistically better than monocentric models, and there was some shift in employment distribution toward a more polycentric pattern. These findings verify the existence of polycentricity in Los Angeles and demonstrate for the first time that employment and especially population follow a polycentric pattern based on exogenously defined employment centers. The results confirm that both employment and population became more dispersed during the 1970s."

Americas↗
PubMed1994

Effects of long-term treatment of captopril and enalapril on rat intestinal angiotensin converting enzyme specific activities.

OBJECTIVES: Angiotensin converting enzyme (ACE) has been shown to be an important peptidasse that play a role in digestion and assimilation of protein rich in proline such as casein, gliadin and collagen. Despite that ACE inhibitors have been popular for various types of hypertension and congestive heart failure, the effects of their long-term treatment on intestinal ACE activities are not known. Therefore, we measured intestinal specific activities in rats after four weeks' treatment of ACE inhibitors. METHODS: Thirty Wistar rats weighing about 200g in average were divided into three groups, and supplied with tap water, captopril solution and enalapril solution respectively for four weeks. After sacrificing, intestinal ACE specific activities were measured in homogenate and brush border membrane fraction respectively, which was prepared from three equally divided segments of removed small intestine. RESULTS: ACE specific activities of proximal, middle and distal segments of control group were 178.6 +/- 64.2, 180.3 +/- 60.2 and 48.6 +/- 13.1 in brush border membrane (mean +/- SD, nmol/min/mg protein) respectively. Those of captopril group were 314.2 +/- 72.5, 281.0 +/- 69.8 and 67.7 +/- 21.8 respectively, showing tendency of increase in proximal and middle segments (p < 0.01 and 0.05 respectively). By contrast, those of enalapril group were 48.5 +/- 27.6, 70.7 +/- 15.6 and 11.6 +/- 4.4 respectively, which were significantly lower (p < 0.01) than those of control group. CONCLUSION: Rat intestinal ACE specific activities were not inhibited by captopril treatment, but inhibited by enalapril treatment. This finding may explain why there has not been any case report of malabsorption in patients taking captopril. But the malabsorption of prolyl peptide could be possible in cases with long-term administration of enalapril.

Animals↗
PubMed1993

Solvent oxygen is not incorporated into N10-formyltetrahydrofolate in the reaction catalyzed by N10-formyltetrahydrofolate synthetase.

The mechanism of the reaction catalyzed by N10-formyltetrahydrofolate synthetase involves the formation of formyl phosphate as an intermediate which then formylates tetrahydrofolate at the N-10 position. Previous studies demonstrated that the non-enzymic formylation of tetrahydrofolate by formyl phosphate occurs exclusively at the more nucleophilic 5-nitrogen in the reduced pyrazine ring. The experiments described in this report were designed to determine whether N5-formyltetrahydrofolate might be the first product to be formed on the enzyme, followed by formyl transfer to the 10-nitrogen via the cyclic intermediate N5,10-methenyltetrahydrofolate. If this were the case, oxygen from solvent H2O would be incorporated into the formyl group of the N10-derivative. By conducting the reaction in a 1:1 mixture of [16O]H2O and [18O]H2O and using 13C NMR spectroscopy we show that no 18O is incorporated into the product and conclude that the reaction proceeds via a direct formylation of the N-10 position by formyl phosphate.

Catalysis↗
PubMed1993

Protein-heme interactions in hemoglobin from the mollusc Scapharca inaequivalvis: evidence from resonance Raman scattering.

Resonance Raman spectra of the Scapharca inaequivalvis homodimeric hemoglobin (HbI) have been measured for the ligand-bound and ligand-free ferrous forms of the protein. In the deoxy derivative, the iron-histidine (Fe-His) stretching mode, proposed as a marker of the oxygen affinity and a conduit linking the hemes to the subunit interface, gives rise to a Raman peak centered at 203 cm-1, an unusually low frequency compared to that reported for other hemoglobins and myoglobins. In the CO-bound derivative, three isotope-sensitive lines at 517, 583, and 1945 cm-1 have been assigned to the Fe-CO stretching, Fe-C-O bending, and C-O stretching modes, respectively. From the frequencies of these modes and from their relative intensities, the Fe-C-O geometry appears to be tilted from axial coordination and shows a bending angle which has been estimated to be about 171 +/- 5 degrees. For the oxygen derivative, only one isotope-sensitive peak has been detected at 570 cm-1, in line with the values found for myoglobin and other hemoglobins. Resonance Raman spectra of HbI modified with p-(chloromercuri)benzoate (PMB) at Cys92 have been measured in parallel with those of the native protein. Despite the large increase in oxygen affinity produced by the PMB modification, the frequency of the Fe-His stretching mode is unshifted in the deoxy derivative.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗