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Biomedical subjects

D Ma

Publications and source records attributed to D Ma.

At least 127 records · Page 7Linked to original sources
PubMed1999

[Effects of ligustrazine on plasma platelet aggregation rate, thromboxane B2, 6-keto-prostaglandin F1 alpha and von Willebrand's factor in patients with acute onset of cor pulmonale].

OBJECTIVE: To study the effect on large dose of Ligustrazine on the function of platelet and endothelial cells of patients with acute onset of cor pulmonale. METHODS: Platelet aggregation rate (PAR), thromboxane B2 (TXB2), 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), von Willebrand's factor (vWF), PaO2 and PaCO2 were assayed in 30 patients with acute onset of cor pulmonale and 26 cases of control before and after treatment of large dose of Ligustrazine. RESULTS: PAR, vWF, TXB2, TXB2/6-keto-PGF1 alpha and PaCO2 decreased (P < 0.05, P < 0.01), and 6-keto-PGF1 alpha, PaO2, SaO2 increased (P < 0.01) after treatment of Ligustrazine, and only PaCO2 decreased in control. CONCLUSION: Ligustrazine had the function of antiplatelet and protecting the endothelial cells. Large dose (800 mg/d) had no side-effects.

6-Ketoprostaglandin F1 alpha↗
PubMed1999

[Evaluation of normal submandibular gland function by sialo-scintigraphy].

OBJECTIVE: To study the normal glandular function of the submandibular gland as a background for evaluation of changes in submandibular gland diseases. METHODS: The backgrounds of both submandibular area and temporal area were analyzed comparatively with Emission Computerized Tomography in eleven pairs of normal submandibular gland. RESULTS: About 2.18 times of the temporal background equals to submandibular area background; the Concentrate Index of normal submandibular gland was 1.42 +/- 0.89; the Secretory Index was (109.4 +/- 39.8)%, the Secretory Index Ratio and the Concentrate Index Ratio were (77.2 +/- 17.2)% and 71.0 +/- 15.2% respectively; and the Function Index was (89.9 +/- 7.4)%. CONCLUSION: The use of submandibular area background and functional index to represent submandibular gland function is more accurate and more sensitive. Normal functional index can provide the basis for researching submandibular gland disease.

Humans↗
PubMed1999

[Separation of p-aminobenzenearsonic acid and its oxide by ion-pair reversed-phase high performance liquid chromatography].

To study the separation of p-aminobenzenearsonic acid (PABAA) and its oxide, p-aminophenylarsine oxide (PAPAO), both the absorption spectra were scanned at the wavelengths from 200 nm to 380 nm. PABAA had absorption maximum at 254 nm and PAPAO 258 nm. The effects of salt concentration, column temperature, methanol and ion-pair agent concentrations on the capacity factor were investigated. Compounds of high polarity showed almost no retention on reversed-phase column; as the volume fraction of the methanol decreased from 90% to 10%, the retention time of PABAA gradually increased with broad peak, and partially eluted when methanol volume fraction being below 20%. With temperature rising, the retention time of PABAA was decreased. But PABAA capacity factor can be increased by selecting an appropriate salt concentration for the mobile phase. The cetyltrimethyl and tetrabutyl ammonium ions were separately added as ion-pair agents to the mobile phase containing methanol in phosphate buffer of 10 mmol/L, the changes of retention time were observed. The mechanism of retention based on reversed phase ion-pair model is proposed. Besides, the retention behaviour is also influenced by size exclusion in stationary phase as well as polar interactions with residual silanol group on the silica surface.

Arsanilic Acid↗
PubMed1999

[Registration and fusion of multimodality medical images].

This paper introduces the present situation of research and methods of multimodality medical images fusion. Some algorithms and relative techniques are given in detail. A summary of the clinical application of multimodality medical images fusion is also presented.

Algorithms↗
PubMed1999

[Limited diffraction beams and its application].

Limited diffraction beams have a large depth of field and thus have many applications such as medical imaging, tissue characterization, material flaw detection and blood flow detection by Doppler method. Nondiffraction beams colud be produced only by transducer with an infinity large aperture in theory. The experimental results show that limited diffraction beams produced by a limited aperture have desirable large depth of field also. The theory of this kind of beams and their applications in field of medical imaging and blood flow estimation are introduced.

Acoustics↗
PubMed1999

[EB virus infection and expression of P53 and P16 in non-Hodgkin's lymphoma].

OBJECTIVE: To observe the presence of Epstin-Barr virus (EBV) and expression of P53 and P16 in the non-Hodgkin's lymphoma (NHL) occurring in the nasal cavity and pharyngeal Waldeyer's ring. METHODS: In situ hybridization was used to detect EBV-DNA and P16-mRNA and immunohistochemical staining was used to examine the expression of LMP1, P53 and P16 in the 36 cases. Five cases whose EBV-DNA were negative at first assay by hybridization was re-detected for EBV-DNA by PCR. RESULTS: Positive expression rates of EBV-DNA, LMP1, P16 mRNA, P53 and P16 were 63.9%, 27.8%, 30.6%, 19.4% and 22.2%. P53 and P16 expressions were not significantly different between T cell NHL and B cell NHL, nor were them significantly different between EBV positive and negative cases. CONCLUSION: A higher percentage of EBV infection was detected in the nasal cavity and pharyngeal Waldeyer's ring in NHL. EBV infection was not significantly associated with P53 and P16 expresions in NHL.

Cyclin-Dependent Kinase Inhibitor p16↗
PubMed1999

[Synthesis of the new reagent N-hexyl-N'-(sodium aminobenzenesulfonate) thiourea (HXPT) and its spectrophotometric study with Pd2+].

A new reagent N-Hexyl-N'-(sodium aminobenzenesulfonate) thiourea (HXPT) was synthesized. Its structure was also characterized. A new spectrophotometric method of determining Pd2+ was developed based on the new reagent. In the range of pH 5.4-5.8 Pd2+ forms a stable yellow complex with HXPT in the presence of CTMAB,and its apparent molar absorptivity is 2. 21 x 10(5) L x mol(-1) x cm(-1) at the maximum absorption wavelength 296.8 nm. Beer's law is obeyed in the range of 1-7 microg x 25 mL(-1) for Pd2+. This method has been used for the determination of trace Pd2+ in ores and catalyst with satisfactory results.

English Abstract↗
PubMed1998

Rituximab (anti-CD20 monoclonal antibody) for the treatment of patients with relapsing or refractory aggressive lymphoma: a multicenter phase II study.

Rituximab, a chimeric monoclonal antibody that binds specifically to the CD20 antigen, induced objective responses in 50% of patients with low-grade or follicular B-cell lymphoma. Because most nonfollicular B-cell lymphomas also express the CD20 antigen, we conducted a phase II study to evaluate the efficacy and tolerability of this new agent in patients with more aggressive types of lymphoma. Patients with diffuse large B-cell lymphoma (DLCL), mantle cell lymphoma (MCL), or other intermediate- or high-grade B-cell lymphomas according to the Working Formulation were included in this prospective randomized phase II study if they were in first or second relapse, if they were refractory to initial therapy, if they progressed after a partial response to initial therapy, or if they were elderly (age >60 years) and not previously treated. The patients received 8 weekly infusions of rituximab at the dose of 375 mg/m2 in arm A or one infusion of 375 mg/m2 followed by 7 weekly infusions of 500 mg/m2 in arm B. Patients were evaluated 2 months after the last rituximab infusion. Fifty-four patients were randomized from 9 centers in Europe and Australia (28 in arm A and 26 in arm B). A total of 5 complete responses (CR) and 12 partial responses (PR) were observed among the 54 enrolled patients, with no difference between the two doses. In an intent-to-treat analysis, the CR rate was 9% (CI95%, 3% to 20%) and the PR rate was 22% (CI95%, 12% to 36%), for an overall response rate of 31% (CI95%, 20% to 46%). An analysis of prognostic factors showed that response rates were lower in patients with refractory disease, patients with lymphoma not classified as DLCL, and patients with a tumor larger than 5 cm in diameter. DLCL and MCL patients had response rates of 37% and 33%, respectively. The median time to progression exceeded 246 days for the 17 responding patients. The most frequently reported adverse events were related to an infusion syndrome and were mild: 19% of the patients had a grade 3 related adverse event, slightly more in arm B, and only 1 patient had a grade 4 related adverse event in arm A. Two patients (3.7%) withdrew from treatment because of severe adverse events, one patient in each arm. In this first trial of rituximab in DLCL and MCL, patients experienced a significant clinical activity with a low toxicity. Rituximab has significant activity in DLCL and MCL patients and should be tested in combination with chemotherapy in such patients.

Adult↗
PubMed1998

1H NMR studies of azide binding to cytochrome c.

The binding of azide ion to the heme iron of ferricytochrome c in D2O is studied using 1H NMR methods at pH 7.0 and 300 K or 315 K. Some hyperfine shifted resonances arising from heme peripheral protons and resonances of side-chain protons of some amino acid residues in N3-cyt c have been assigned using 2D EXSY and DQF-COSY methods. The majority of the heme pocket side-chain proton signals have been identified. The 1D nuclear overhauser effect (NOE) difference spectra and 2D NOESY spectrum are presented and changes in NOE patterns between the heme and certain residues, and several residues around the axial ligand are interpreted in terms of changes in the pocket structure. Interpretation of NOE data indicates that conformation changes are obvious on the Met80 side of the heme cavity in the environment of the axial ligand in N3-cyt c. In addition, kinetics analysis of azide binding to cyt c is studied using 2D EXSY method.

Animals↗
PubMed1998

Crystal structure of the cyclophilin-like domain from the parasitic nematode Brugia malayi.

Cyclophilins are a family of proteins that exhibit peptidyl-prolyl cis-trans isomerase activity and bind the immunosuppressive agent cyclosporin A (CsA). Brugia malayi is a filarial nematode parasite of humans, for which a cyclophilin-like domain was identified at the N-terminal of a protein containing 843 amino acid residues. There are two differences in sequence in the highly conserved CsA binding site: A histidine and a lysine replace a tryptophan and an alanine, respectively. The crystal structure of this domain has been determined by the molecular replacement method and refined to an R-factor of 16.9% at 2.15 A resolution. The overall structure is similar to other cyclophilins; however, major differences occur in two loops. Comparison of the CsA binding site of this domain with members of the cyclophilin family shows significant structural differences, which can account for the reduced sensitivity of the Brugia malayi protein to inhibition by CsA.

Amino Acid Sequence↗
PubMed1998

Restoration of TEA-induced calcium responses in fibroblasts from Alzheimer's disease patients by a PKC activator.

Several alterations in fibroblasts of Alzheimer's disease (AD) patients have been described, including alterations in calcium regulation, protein kinase C (PKC), and potassium (K+) channels. Studies have also found reduced levels of the alpha isoform of PKC in brains and fibroblasts of AD patients. Since PKC is known to regulate ion channels, we studied K+ channel activity in fibroblasts from AD patients in the presence of (2S, 5S)-8-(1-decynyl)benzolactam (BL), a novel activator of PKC with improved selectivity for the alpha, beta, and gamma isoforms. We present evidence for restoration of normal K+ channel function, as measured by TEA-induced [Ca2+]i elevations, due to activation of PKC by BL. Representative patch-clamp data further substantiate the effect of BL on restoration of 113pS K+ channel activity. Immunoblotting analyses using an alpha-isozyme-specific PKC antibody confirm that BL-treated fibroblasts of AD patients show increased PKC activation. The present study suggests that PKC activator-based restoration of K+ channels may offer another approach to the investigation of AD pathophysiology, which in turn could lead to the development of a useful model for AD therapeutics.

Alzheimer Disease↗
PubMed1998

Surgery for intestinal graft-versus-host disease: report of two cases.

PURPOSE: With allogeneic bone marrow transplantation becoming increasingly common, intestinal graft-versus-host disease often is seen within specialized transplant units. Surgeons are involved infrequently in the management of such patients, and yet occasionally are called upon to operate on critically ill patients with refractory disease. This article reviews the salient features of this condition and discusses possible indications for surgery. METHOD: Two cases of intestinal graft-versus-host disease that required laparotomy are presented. RESULTS: A 24-year-old male with severe, unremitting, acute intestinal graft-versus-host disease underwent small-bowel and large-bowel resections for massive bleeding. A 35-year-old male with recurrent symptoms of small-bowel obstruction after allogeneic bone marrow transplantation underwent small-bowel resection and multiple strictureplasties for chronic intestinal graft-versus-host disease. CONCLUSION: Surgery can be performed for complications of intestinal graft-versus-host disease not responding to medical therapy, with successful outcome.

Adult↗
PubMed1998

Lidocaine prolongs the safe duration of circulatory arrest during deep hypothermia in dogs.

PURPOSE: To test the hypothesis that lidocaine prolongs the safe period of circulatory arrest during deep hypothermia. METHODS: Sixteen dogs were subjected to cooling, first surface cooling to 30 degrees C and then core cooling to 20 degrees C rectal temperature). The circulation was then stopped for 90 min. In the lidocaine group, 4 mg.kg-1 lidocaine was injected into the oxygenator two minutes before circulatory arrest and 2 mg.kg-1 at the beginning of reperfusion and rewarming. The control group received equivalent volumes of normal saline. Post-operatively, using a neurological deficit scoring system (maximum deficit score-100; minimum-zero indicating that no scored deficit could be detected). Neurological function was evaluated hourly for six hours and then daily for one week, the pharmacokinetic parameters were calculated using one compartment model. RESULTS: On the seventh day, the neurological deficit score and overall performance were better in the lidocaine (0.83 +/- 2.04) than in the control group (8.33 +/- 4.08 P < 0.05). During the experiment, the base excess values were also better in the lidocaine than in the control group (at 30 min reperfusion: -4.24 +/- 1.30 vs -8.20 +/- 2.82 P < 0.01, at 60 min reperfusion was -3.34 +/- 1.87 vs -7.52 +/- 2.40 (P < 0.01). On the eighth day the extent of pathological changes were milder in the lidocaine group than that in the control group. The elimination half life of lidocaine was 40.44 +/- 7.99 during hypothermia and 2.01 +/- 4.56 during rewarming. CONCLUSIONS: In dogs lidocaine prolongs the safe duration of circulatory arrest during hypothermia.

Anesthetics, Local↗
PubMed1998

Metabolism of cystathionine, N-monoacetylcystathionine, perhydro-1,4-thiazepine-3,5-dicarboxylic acid, and cystathionine ketimine in the liver and kidney of D,L-propargylglycine-treated rats.

Experimental cystathioninuria was induced by injection of D,L-propargylglycine in rats. The novel cystathionine metabolites, N-monoacetylcystathionine (NAc-cysta), perhydro-1,4-thiazepine-3,5-dicarboxylic acid (PHTZDC), and cystathionine ketimine (CK), were identified previously in the urine of patients with cystathioninuria and D,L-propargylglycine-treated rats. In this study, we identified these compounds in the liver and kidney of D,L-propargylglycine-treated rats using liquid chromatography-mass spectrometry with an atmospheric pressure chemical ionization interface system (LC/APCI-MS) and an amino acid analyzer. The metabolism of these compounds in the liver and kidney of D,L-propargylglycine-treated rats was also studied. PHTZDC, NAc-cysta, and CK were accumulated in the rat tissues in proportion to the content of cystathionine after D,L-propargylglycine administration. The concentrations of these compounds in the liver were higher than those in the kidney, and these compounds reached maxima earlier in the liver than in the kidney.

Alkynes↗