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Biomedical subjects

M Du

Publications and source records attributed to M Du.

At least 73 records · Page 4Linked to original sources
PubMed1999

Immunolabeling of the major cell surface protein antigen of Streptococcus sobrinus with monoclonal antibody.

OBJECTIVE: The purpose of this study was to determine the accessibility of monoclonal antibody (McAb), specific for the major cell surface protein antigen (PAg) of Streptococcus sobrinus, to the surface of its native epitopes. MATERIALS AND METHODS: An indirect immunogold labeling technique was used to detect the reaction of McAb with S. sobrinus 6715. The reactions of polyclonal antibodies (PcAbs) against S. sobrinus 6715 or PAg with S. sobrinus 6715, S. mutans Ingbritt C and S. rattus BHT were studied as controls. RESULTS: The results indicated that PAg was localized on the outer cell surface of S. sobrinus, and McAb was reactive with only a few epitopes of the cell surface, whereas PcAbs were found to be reactive with more epitopes. CONCLUSIONS: McAb was specific for the PAg, but there was cross-reaction with S. mutans. Also there seemed to be an association between the fuzzy coat on the surface of S. sobrinus and PAg.

Adhesins, Bacterial↗
PubMed1999

[Serum levels of levonorgestrel during long-term use of Norplant].

OBJECTIVE: (1) Assessment of longest effective contraceptive duration of Norplant (containing levonorgestrel, LNG) by serum levonorgestrel levels. (2) To observe the possible relationships between the serum LNG levels of long-term use (5 years) and body weight. METHODS: To determine serum LNG levels in 230 women among 1,356 cases at various intervals between 1 and 11 years after implantation using RIA kits provided by WHO. RESULTS: The average serum levels of LNG in users of Norplant at the 1st, 3rd, 5th years were 1,273.5, 924.0 and 739.6 pmol/L respectively. From the 5th to 7th years average serum LNG levels showed almost a linear decline, and from the 7th through 10th year it did not show much changes. The average serum LNG level was (511.1 +/- 209) pmol/L. A significant negative correlation was found between serum LNG levels and body weight at the 5th years. CONCLUSION: One set of Norplant implants may provide effective contraception for 8-10 years in women with body weights less than 60 kg.

Adult↗
PubMed1999

[A pathological study on pulmonary fibrosis caused by chronic obstructive pulmonary disease].

OBJECTIVE: To estimate the morphologic characteristics of chronic obstructive pulmonary disease (COPD) induced pulmonary fibrosis. METHODS: 41 autopsy cases of COPD were chosen as the study group and other 10 autopsy cases died from non-respiratory diseases as control group. Histochemical stain and image quantitative analysis were used to identify the type of collagen. RESULTS: In 36 cases (88%) of study group, fibrosis proliferation could be seen in peri-bronchial area, especially in the bronchi under grade VI. Respiratory bronchiole and alveoli were also involved in 11 cases. The main component of collagen in fibrosis area was identified as type III collagen by sirius red stain, reticular fiber could also be seen by Gomori stain. The type III collagen in alveoli distributed interruptedly. Image quantitative analysis showed: the integral optical density (A) of type III collagen was much higher than that of type I collagen in peri-bronchial area (P < 0.01); Both A of type III and type I collagen in peri-bronchial area were higher than that in alveolar area (P < 0.01). Mucous purulent plugs, interrupted elastic fibers in bronchial wall and chronic inflammation accompanied with lymphocytes infiltration in fibrosis area could also be seen. CONCLUSIONS: COPD induced pulmonary fibrosis distributed mainly in peri-bronchial area, especially in the bronchi under grade VI. The main component of proliferative collagen was type III collagen. The genesis of pulmonary fibrosis might be associated with chronic inflammation accompanied with lymphocytes. Peri-bronchial fibrosis, interrupt of elastic fibers in bronchial wall caused the bronchial lumen narrowed or collapsed making both airway obstruction and ventilation insufficiency deteriorated.

Aged↗
PubMed1998

Cloning and expression analysis of a novel salicylate suppressible gene, Hs-CUL-3, a member of cullin/Cdc53 family.

By using a mRNA differential display technique to search for salicylate suppressible genes, we identified a cDNA in human foreskin fibroblasts, which by GenBankTM DNA data base search shows sequence homology to the recently reported cullin/Cdc53 (CUL) family genes, especially CUL-3. We have cloned the full-length human CUL-3 (Hs-CUL-3) cDNA. It encodes a 768-amino acid polypeptide and has a predicted molecular weight of 88,939. The amino acid sequence of Hs-CUL-3 shows 46% homology to that of its Caenorhabditis elegans ortholog, Ce-CUL-3, and 27 and 23% to that of Hs-CUL-1 and Hs-CUL-2, respectively. Northern blot analysis showed that phorbol 12-myristate 13-acetate increased the expression of Hs-CUL-3 mRNA in a concentration- and time-dependent manner, and this increase was inhibited by sodium salicylate. Hs-CUL-3 widely expressed in human tissues and its expression in cultured COLO205 colon cancer cells was increased when compared with that in normal colon cells. It is likely that Hs-CUL-3 is involved in cell proliferation control.

Amino Acid Sequence↗
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

Imbalance between proliferation and apoptosis in the development of colorectal carcinoma.

To evaluate the relationship between cell proliferation and apoptosis in sporadic colorectal carcinogenesis, immunohistochemistry for proliferation-associated antigen Ki-67 and in situ end labelling for identifying apoptotic bodies were performed on paraffin sections from 59 adenomas and 22 carcinomas. These results were correlated with the expression of the proliferation and apoptosis modulators Bcl-2 and p53. Carcinomas showed increased proliferation and apoptosis compared with adenomas (P<0.0001, P<0.001, respectively). There were positive linear correlations between proliferation and apoptosis in adenomas and carcinomas (P<0.02, P<0.05, respectively). The proliferative rate increased significantly from mild to moderate, and from moderate to severe dysplasia (P<0.002, P<0.001, respectively). Apoptotic rate also increased in this sequence, but the increases did not reach statistical significance (both P>0.05). Expression of Bcl-2 was associated with lower apoptotic rate in adenomas (P<0.025) but not in carcinomas (P>0.25), whereas p53 expression was correlated with higher proliferative rate in both adenomas and carcinomas (P<0.01, P<0.05, respectively). An inverse relationship between Bcl-2 and p53 expression was seen in both adenomas and carcinomas (P<0.05, P<0.005, respectively). These data suggest that the normal balance between proliferation and apoptosis is disturbed in colorectal carcinogenesis, both being increased, but proliferation occurs in excess. Bcl-2 and p53 may each play a role in modulating cell apoptosis or proliferation during the development of colorectal carcinoma.

Adenoma↗
PubMed1998

The anesthetic isoflurane decreases ionized calcium and increases parathyroid hormone and osteocalcin in cynomolgus monkeys.

The effects of anesthetics on calcium metabolism in cynomolgus monkeys were studied. Eight adult female cynomolgus monkeys were used in a crossover design. Blood was collected from each of the monkeys at four timepoints: (1) while conscious; (2) following induction of anesthesia with ketamine, ketamine and atropine, isoflurane, or no anesthetic; (3) at 30 min; and (4) 120 min thereafter. Four experiments were performed with a 1 week washout period between sessions, such that each monkey received each treatment. Potassium was lower in anesthetized monkeys than in those that remained conscious. Cortisol, although high, did not differ among anesthetic treatments. Ketamine and ketamine/atropine did not consistently affect ionized calcium or parathyroid hormone (PTH) concentrations. Isoflurane decreased ionized calcium (0.05 mmol/L), and increased PTH and osteocalcin twofold. The serum inorganic fluoride concentration was higher in monkeys anesthetized with isoflurane than with ketamine/atropine, which may partially account for the decrease in ionized calcium with isoflurane. The increases in PTH and osteocalcin are presumably secondary to the decrease in ionized calcium.

Anesthetics, Inhalation↗
PubMed1998

Compound GW506U78 in refractory hematologic malignancies: relationship between cellular pharmacokinetics and clinical response.

PURPOSE: In vitro investigations with arabinosylguanine (ara-G) demonstrated potent cytotoxicity to T-lymphoblastoid cell lines. The goals of the present study were to evaluate GW506U78, a prodrug of ara-G, against human hematologic malignancies and to determine its pharmacokinetics in plasma and cells. PATIENTS AND METHODS: During a phase I multicenter trial of GW506U78, 26 patients were treated at M.D. Anderson Cancer Center (MDACC). Daily doses between 20 and 60 mg/kg were administered for 5 days. Parallel plasma and cellular pharmacokinetic studies were conducted. RESULTS: Complete (n=5) or partial remission (n=5) was achieved in T-cell acute lymphoblastic leukemia (T-ALL), T-lymphoid blast crisis, T-lymphoma, and B-cell chronic lymphocytic leukemia (B-CLL) (n=13). In contrast, patients with B-ALL, B-lymphoma, acute myelogenous leukemia (AMI), or T-CLL did not respond. Peak plasma concentrations of GW506U78 and ara-G were dose-dependent. The elimination of GW506U78 (half-life [t1/2]=17 minutes) was faster than the elimination of ara-G (t1/2=3.7 hours). Median peak concentrations of ara-GTP were 23, 42, 85, and 93 micromol/L at 20, 30, 40, and 60 mg/kg, respectively. T-lymphoblasts accumulated significantly (P=.0008) higher peak arabinsylguanosine triphosphate (ara-GTP) (median, 140 micromol/L; n=7) compared with other diagnoses (median, 50 micromol/L; n=9) and normal mononuclear cells (n=3). The ara-GTP elimination was slow in all diagnoses (median, > 24 hours). Responders accumulated significantly (P=.0005) higher levels of ara-GTP (median, 157 micromol/L) compared with patients who failed to respond (median, 44 micromol/L). CONCLUSION: GW506U78 is an effective prodrug and a potent agent for hematologic malignancies with major efficacy in T-cell diseases. The pharmacokinetics of ara-GTP in leukemia cells are strongly correlated with clinical responses to GW506U78.

Adult↗
PubMed1998

A pathological study of in situ thrombosis of small pulmonary arteries and arterioles in autopsy cases of chronic cor pulmonale.

OBJECTIVE: To investigate the incidence of in situ thrombosis of small pulmonary arteries and arterioles during the exacerbation stage of chronic cor pulmonale. METHODS: 49 autopsy cases died from the exacerbation of chronic cor pulmonale were chosen as the study group, while 103 other autopsy cases without chronic cor pulmonale and disseminated intravascular coagulation (DIC) as control group. Morphologic and morphometric studies were taken on lung tissues and other organs with focus on the thrombi in small pulmonary arteries and arterioles. RESULTS: 44 cases of the study group had multiple thrombi in small pulmonary arteries and arterioles, the incidence is 89.8%, and in 9 of them, thrombi in proximal pulmonary arteries co-existed, the incidence is 18.4%. 80% of the thrombi existed in pulmonary arterioles. In the control group, only 3 cases had thrombi in small pulmonary arteries and arterioles, the incidence is 2.9%. All thrombi adhered to endangium, implying that they were in situ thrombi. No intravascular thrombosis was found in other organs. chi 2 test showed that the incidence of thrombosis and the number of thrombi in small pulmonary arteries and arterioles in cases with chronic cor pulmonale were significantly higher than those of the control group (P < 0.01). CONCLUSIONS: Multiple in situ thrombosis in small pulmonary arteries and arterioles is a prominent and common pathological change during the exacerbation stage of chronic cor pulmonale. The study suggests a new diagnostic and therapeutic concept and gives a morphological and theoretical basis for the clinical application of anticoagulants or even the thrombolytic agents for the cases of chronic cor pulmonale in the exacerbation stage.

Aged↗
PubMed1998

[The experimental study of immunization with purified surface protein antigen I/II from streptococcus mutans in BALB/c mice].

OBJECTIVE: To study the immunogenicity and immunoreactivity of purified surface protein antigen I/II from streptococcus mutans. METHODS: Purified antigen I/II was used to immune BALB/c mice by subcutaneous injection route, and S. mutans whole cells were used as comparison. RESULTS: ELISA showed immunization with antigen I/II highly induced both specific serum IgG antibody and specific salivary IgA antibody against antigen I/II (P < 0.01), but immunization with whole cells only induced specific serum IgG antibody (P < 0.05). CONCLUSION: The study suggest purified antigen I/II is an effective candidate vaccine.

Animals↗
PubMed1998

[Host-guest molecule interaction mechanism of hemostatics with liposomes and red blood cells studied with fluorescence polarimetric method].

The supermolecule compounds of adrenobazone, p-aminomethylbenzoic acid, vitamin K1, 6-amino caproic acid with liposomes and red blood cells were studied by fluorescence polarimetric method. The mechanisms of formation of the supermolecule compounds were examined by fluorescence probe of the link of 1,6-dipheny-1,3,5-hexatriene (DPH) with liposomes which were taken as a model of blood cells. The interaction mechanism of hemostatics with red blood cells was described according the quantitative relationship between polarization value (P) and the microviscosity [formula: see text]. The result showed that the acting force between hemostatics and liposomes or that between hemostatics and red blood cells were mainly supermolecular acting force. The acting force between vitamin K1 and cytomembrane is hydrophobic force and those between adrenobazone, p-aminomethylbenzoic acid, or 6-amino caproic acid and cytomembrane are hydrogen bond or electrostatic force. Under the same drug concentration, all of the four haemostatics can reduce the fluidity of the cell membrane, which benefits blood coagulation. The binding ways of hemostatics with red blood cells was also discussed.

4-Aminobenzoic Acid↗
PubMed1998

[Crackle detection and classification based on matched wavelet transform].

In this paper, we present a method for crackle detection which is based on 'matched' wavelet transform. We first modeled crackles as a mathematical function. Then we designed a matched mother wavelet based on this model. Applying a soft-threshold to the results of the continuous wavelet transform to suppress noise further, we obtained the optimal scale Crackles were detected based on the envelope of the signal at optimal scale, and could be classified based on energy distribution with scale. The theory, methods and experimental results are given in detail.

Algorithms↗
PubMed1997

Identification of alternative first exons of NADH-cytochrome b5 reductase gene expressed ubiquitously in human cells.

Two forms of NADH-cytochrome b5 reductase (b5R), soluble and membrane-bound, are known. A hypothesis that the human soluble form b5R is generated through post-translational processing of the membrane-bound form was previously proposed. In this study, the 5'-rapid amplification of cDNA ends for human reticulocyte, liver, brain, and HL-60 cell mRNAs revealed the ubiquitous presence of an alternative type of human b5R mRNA which can probably be translated into the soluble form b5R directly; however, the erythroid-specific transcript of the b5R gene was not found. This type of b5R mRNA initiating from at least two sites contains a non-coding new first exon located between the first two exons of the human b5R gene identified before. In addition, this new first exon shares 62% homology with the first exon and its 3'-flanking intron sequences of rat erythroid-specific b5R mRNA, whereas the 5'-flanking region of the new first exon possesses features of house-keeping gene. These results might be important to understand the regulation mechanism of human b5R biosynthesis and divergent evolution of the gene regulation.

Animals↗
PubMed1997

Clonality analysis in tumours of women by PCR amplification of X-linked genes.

Modifications have been made to two polymerase chain reaction (PCR) methods for clonality analysis based on the inactivation patterns of two highly polymorphic X-linked genes encoding the androgen receptor (AR) and monoamine oxidase A (MAOA). These methods have been used to examine the clonal nature of frozen tissues from 42 tumours and 25 non-tumour controls from female subjects. Unbalanced inactivation patterns of the genes, which indicate monoclonality, were frequently observed in tumours of heterozygous (informative) cases (18/35 = 51.4 per cent for the AR gene, 9/30 = 30 per cent for the MAOA gene, and 21/38 = 55.2 per cent for both). Among 23 informative non-tumour controls, only one (4.3 per cent), a reactive lymph node, showed skewing in the AR gene. Successful detection of monoclonality was found to depend on the proportion of tumour cells in the tissues examined. None of the AR or MAOA informative cases containing less than 50 per cent of tumour cells showed imbalance in inactivation patterns. With more than 50 per cent of tumour cells in the samples, 66.6 per cent (18/27) of AR and 39.1 per cent (9/23) of MAOA informative cases showed allelic imbalance, with a combined frequency of 72.4 per cent (21/29) of both genes. Our results demonstrate that the methods described are useful for clonal analysis of tissue samples from female patients.

Breast Neoplasms↗
PubMed1997

Contraceptives for lactating women: a comparative trial of a progesterone-releasing vaginal ring and the copper T 380A IUD.

From approximately one week before normal ovulation resumes, lactating women require protection against pregnancy by a contraceptive that is safe for both infant and mother in a multicenter one-year study, the natural hormone, progesterone, delivered vaginally by a sequence of four contraceptive rings designed for continuous use, was evaluated as a contraceptive for nursing mothers in comparison with the Copper T 380A IUD. Individual rings release in effective average dose of 10 mg day for a 3 month period. Evaluation included measures of lactational performance as well as of contraceptive efficacy and safety to mother and child. Nine participating clinics enrolled 802 ring users and 734 IUD acceptors between postpartum days 29 and 63. Life table analyses were performed with parallel decrements for ring and IUD subjects. Continuation in the study and analysis required that subjects not stop breastfeeding. The ring, with a one-year pregnancy rate of 1.5 per 100, did not differ significantly from the IUD with respect to contraceptive effectiveness (p > 0.05). More than half of the ring subjects were continuing at 6 months post admission and a quarter (23.5 per hundred) were still using the ring and breastfeeding one year after admission. Women with the IUD, however, had higher continuation rates (p < 0.001) at both time points. The largest single decrement for each method was that for weaning. Ring users had more complaints of vaginal problems but had fewer vaginal disorders on examination. At 12 months postpartum, 46 per 100 continuing ring users remained in amenorrhea. Lactation performance and the health and weight gain of the infants were similar among users of either regimen.

Administration, Intravaginal↗
PubMed1997

Genetic evidence for a clonal link between low and high-grade components in gastric MALT B-cell lymphoma.

High-grade MALT lymphomas often contain low-grade tumour components; both cell populations have been shown to express the same immunoglobulin light chain previously. However, the clonal link between the low and high-grade components has not been established at the genetic level. To investigate this link, we have examined low- and high-grade components micro-dissected from tissue sections of four high-grade gastric MALT lymphomas. PCR and sequence analyses were performed to identify clone-specific rearranged immunoglobulin heavy chain gene sequences. In each of these cases, the PCR products from the two components were identical in size by electrophoresis. Direct sequencing revealed common clone-specific immunoglobulin heavy chain gene rearrangements in both lesions of each case, providing genetic evidence for a clonal link. These results support the proposal that high-grade MALT lymphomas generally evolve from low-grade clones.

Base Sequence↗
PubMed1997

Promotion of proliferation of murine BALB/C3T3 fibroblasts mediated by nitric oxide at lower concentrations.

This study showed that nitric oxide (NO)-generating S-nitrosothiols, S-nitroso-N-acetylpenicillamine (SNAP) and S-nitrosoglutathione (GSNO), increased proliferation of BALB/c 3T3 (clone A31-1-1) fibroblasts in vitro. Treatment with SNAP at a relatively low concentration (0.005-0.02 mM) induced an increase in cell number compared to control. SNAP (0.005-0.02 mM) and GSNO (0.025-0.05 mM) both showed an increase of [3H]thymidine incorporation in exponentially growing cells in a dose-dependent manner. The maximal effect was observed at about 40 and 90% above control at 0.02 mM and 0.05 mM, respectively. The increase induced by 0.02 mM SNAP was abolished by the addition of 0.01 mM oxyhemoglobin, a scavenger of NO. [3H]Thymidine incorporation in stationary cells was also increased by SNAP. In addition, 0.02 mM SNAP produced a 1.8-3.2-fold increase of thymidine kinase activity in exponentially growing cells.

3T3 Cells↗