Biomedical subjects

M Yang

Publications and source records attributed to M Yang.

At least 325 records · Page 18Linked to original sources

PubMed1997

Helicobacter pylori Lewis expression is related to the host Lewis phenotype.

BACKGROUND & AIMS: Lewis antigens occur in human gastric epithelium and in Helicobacter pylori lipopolysaccharide; their expression is polymorphic in both. Autoimmune mechanisms induced by bacterial Lewis expression have been proposed to cause gastritis. The aim of this study was to examine the relationship between bacterial and host gastric Lewis expression, as determined by the erythrocyte Lewis(a/b) phenotype, and between gastric histopathology and bacterial Lewis expression. METHODS: H. pylori Lewis expression was determined by enzyme immunoassays, erythrocyte Lewis phenotype was assessed by agglutination tests, and gastric histopathology was scored blindly. RESULTS: The host Lewis phenotype was (a+b-) in 15, (a-b+) in 34, and (a-b-) in 17 patients, therefore expressing Lewis x, y, or neither as their major gastric epithelial Lewis type 2 antigen. H. pylori from patients with Lewis(a+b-) expressed Lewis x more than y (1147 +/- 143 vs. 467 +/- 128 optical density units [ODU]; P = 0.006), isolates from patients with Lewis(a-b+) expressed Lewis x less than y (359 +/- 81 vs. 838 +/- 96 ODU; P = 0.0001), and isolates from Lewis(a-b-) patients expressed Lewis x and y approximately equally. Gastritis was unrelated to H. pylori Lewis expression. CONCLUSIONS: In mimicking host gastric epithelium, H. pylori cells not only express Lewis x and y, but the relative proportion of expression corresponds to the host Lewis phenotype, suggesting selection for host-adapted organisms.

Adult↗

PubMed1997

Cloning and functional analysis of rat cyclin D2 promoter: multiple prolactin-responsive elements.

Structure and function of the promoter region of rat cyclin D2 gene were investigated by cloning, sequence analysis and DNA mobility shift assay using nuclear extracts of prolactin-stimulated Nb2 cells. The results show that the expression of rat cyclin D2 gene is not dependent on the TATA-box but is stimulated by multiple transcription factors induced by prolactin at an immediate-early stage of the cell cycle.

Amino Acid Sequence↗

PubMed1997

Appendiceal spirochetosis.

Appendiceal spirochetosis is rarely described in the literature. We assessed the incidence of spirochetosis in a series of 109 appendectomies (76 adult and 33 pediatric cases) done for either suspected acute appendicitis or as a concurrent procedure. Appendiceal spirochetosis was identified on hematoxylin-eosin sections and confirmed by Steiner and Steiner stain and ultrastructural study in two women and two men. One of these four patients was found to have HIV infection. The HIV status of the other three patients was unknown. We observed appendiceal spirochetosis to be an uncommon phenomenon that affects both sexes, occurring with or without symptoms of acute appendicitis. None of our four positive cases occurred in the pediatric age group.

Adolescent↗

PubMed1997

Are intraaortic balloons suitable for reuse? A survey study of 112 used intraaortic balloons.

To assess the safety of reusing single-use intraaortic balloon devices (IABs), 112 used devices were investigated in terms of physical integrity, gas leakage inspection, mechanical performance, surface chemistry and morphology, and physical stability. These IABs were all used clinically only once, and the duration of the IABs in vivo ranged from 6 to 312 h. Macroscopic examination of the balloons and the outer catheters revealed no obvious change in either shape or color. No discernible abrasions or cracks were observed on the balloons. However, 61% of the balloons were creased, and 40% of the central lumens and 21% of the sheaths showed visible bending flaws. Moreover, 65% of the balloons and 38% of the central lumens were contaminated by visible residual organic debris. The physical integrity of each device was verified in a specially designed leakage-fatigue tester for 72 h. Ninety-seven percent of the devices passed the leakage inspection. Stress-strain testing, differential scanning calorimetry, attenuated total reflection-Fourier transform infrared, and scanning electron microscopy analyses clearly indicated that there were no significant differences in the mechanical properties, bulk material morphology, surface chemistry, and external surface morphology between the used balloons and virgin controls. Although some surface modifications occurred on the internal side of the balloons, the external surfaces of most balloons suffered no trauma. Most of the used IABs examined in this study maintained physical and mechanical properties similar to those of the virgin devices. The chemistry of the balloon material was stable after short-term in vivo use. However, it does not seem possible to establish a rigorous protocol of cleaning, sterilization, and inspection to guarantee a safer reuse of these devices. The presence of residual organic debris that cannot be eliminated results in an imperative preclusion not to reuse the IABs.

Calibration↗

PubMed1997

Airway responsiveness in two inbred strains of mouse disparate in IgE and IL-4 production.

The mouse provides an excellent model for genetic studies of asthma, which is characterized by airway hyperexcitability and hyperreactivity. The former is a function of the properties of the membrane of the airway smooth muscle (ASM), whereas the latter is a function, albeit indirectly, of the mechanical properties of the muscle contractile apparatus. The very small size of the muscle has in the past hampered its study. We report herein that contractile properties of tracheal smooth muscle (TSM) can be measured in mice. We examined TSM strips from two inbred strains of mouse, ASW and SJL, which are high and low IgE responders, respectively. Force-velocity relationships were measured in four groups of mice, two ASW (control and sensitized)/and two SJL (control and sensitized). Muscle strips from sensitized SJL mice exhibited shortening velocities (V0) and maximum shortening capacities (deltaLmax), that were significantly greater than those of the other groups. However, no difference was found between the two strains in maximal isometric force (P0). The two strains also showed differences in their potential to express cytokines such as interleukin-4 (IL-4) and IL-5 in ex vivo splenocyte cultures, as measured by the cytokines' messenger RNA (mRNA) and protein expression. The SJL strain, which exhibited TSM hyperreactivity, was found to produce significantly greater amounts of IL-4 than the ASW strain. We conclude that the altered contractile properties of TSM in sensitized SJL mice are independent of IgE response, but linked to increased amounts of IL-4.

Animals↗

PubMed1997

Parent and physician response to children's cholesterol values of 200 mg/dL or greater: the Child and Adolescent Trial for Cardiovascular Health Experiment.

OBJECTIVE: To determine parental actions and concerns and physician responses to parental notification that a child's cholesterol value was 200 mg/dL or greater, a value recommended by the National Cholesterol Education Program to warrant physician follow-up and evaluation. METHODOLOGY: A telephone survey of parents (n = 784) and physicians (n = 117) was carried out after parental notification of a total blood cholesterol value obtained as part of measurement done while participating in the Child and Adolescent Trial for Cardiovascular Health in 96 schools located in California, Louisiana, Minnesota, and Texas. RESULTS: Only 20% of parents contacted physicians. Factors associated with this action included whether the parent was notified once or twice, the level of the cholesterol, previous cholesterol testing in the parent, and medical insurance that covered the visit. Family history of cardiovascular disease, when other factors were considered, did not increase the likelihood that a physician contact would be made. After contact with the physician, 59% of physicians reported evaluating children for cholesterol; about half reported repeating the cholesterol determination. CONCLUSION: Parental knowledge of a child's cholesterol value of 200 mg/dL or greater did not result in substantially further seeking of health care.

Adolescent↗

PubMed1997

Effects of co-supplementation of iron with ascorbic acid on antioxidant--pro-oxidant balance in the guinea pig.

The relationship between intake of iron with ascorbic acid and their uptake into the plasma and liver of guinea pigs was studied. The influence on the antioxidant/pro-oxidant balance of liver microsomes was also determined. Animals were fed a standard pelleted diet low in iron and ascorbic acid for 35 days. The pellet diet was supplemented by oral dosing with a solution containing either maintenance dietary levels of ascorbic acid and iron, or one of three regimens that increased the dosage of these substances ten fold. There were no significant differences in animal growth rate or food intake between these regimens. Liver and plasma total ascorbate levels were significantly increased (p < 0.05) in animals receiving either ascorbic acid alone (liver 126 +/- 36 micrograms/g tissue wet wt. and plasma 51.7 +/- 17.0 microM; n = 9) or ascorbic acid and iron (105 +/- 18 micrograms/g and 40.3 +/- 15.3.0 microM; n = 8) compared to controls (84 +/- 36 micrograms/g and 15.3 +/- 8.5 microM; n = 11). Total iron levels in the liver (76.7 +/- 7.3 micrograms/g; control; n = 6) and plasma (2.4 +/- 0.03 mg/l; control) were not significantly raised in animals under these conditions of iron or ascorbate intake. Liver microsomes isolated from animals receiving iron had a greater susceptibility to oxidative stress in terms of malondialdehyde production during auto-oxidation compared to those from control animals under the same conditions. This effect was eliminated on combining ascorbic acid with the iron supplementation, suggesting that oral administration of vitamin C has a protective rather than a pro-oxidant effect under these circumstances.

Administration, Oral↗

PubMed1997

[Preparation of NADPH-cytochrome P-450 reductase and the role in metabolism of xenobiotics].

NADPH-Cytochrome P-450 Reductase is the major part of MFO (mixed function oxidase) system of liver. A simple and economic method of preparation of reductase was introduced in this paper and it was certified that xenobiotics benzene, bichloroethylene, and asbestos can be oxidized by reductase and reconstituted cytochrome P-450 2B1. But the metabolites of the 3 compounds can not cause the changes of plasmid PBR322 DNA.

Animals↗

PubMed1997

[Construction of Escherichia coli-Mycobacteria shuttle plasmid and the stable expression of human interleukin-2 in BCG and Escherichia coli].

OBJECTIVE: To construct and identify Escherchia coli (E. coli)-Mycobacteria shuttle plasmid and to detect stable expression of foreign gene in E. coli and BCG. METHOD: With a genetic engineering technique to construct the E. coli-Mycobacteria shuttle plasmid, the human interleukin-2 (IL-2) gene was electrophoreted into BCG with recombinant plasmid PZSIII-I and positive clones selected using polymerase chain reaction (PCR) technique. The expression of foreign gene of human IL-2 in BCG was identified by ELISA and SDS-PAGE. RESULT: Human IL-2 cytokine was steadily expressed in recombinant BCG and E. coli and could secrete outside the cell. CONCLUSION: M. bovis BCG recombinant constructed can produce and secrete the human IL-2. A secretion of the active cytokine was accomplished through the combined use of the BCG HSP65 promoter and a secretion signal from the BCG Ag-85B. The BCG HSP65 promoter is active in both BCG as well as E. coli which can not secrete foreign protein.

BCG Vaccine↗

PubMed1997

[Experimental study and clinical use of the dorsal digital flag flap].

To investigate the survival mechanism of the dorsal digital flag flap, an animal experiment was undertaken in a monkey. Eight dorsal digital flag flaps were created and examined by clinical observations, laser Doppler and biopsy. Of them six flaps were proximal-based and two were distal-based. The results showed: 1. The flag flaps survived without purplish discoloration or blister formation when the length-width ratio reached 10:1; 2. The perfusion unit measured by laser Doppler flowmetry decreased on the second postoperative day and began to increase from the third day, and returned to or surpass the preoperative level on the fifth day; 3. Biopsies confirmed that there was no specific artery in the pedicle of the flag flap but a rich dorsal digital venous network. The results indicated that the flag flap is a venous flap. Its arterial perfusion passed through the perivenous vascular network of the pedicle while the venous drainage is through the dorsal digital veins. Based on this study, 20 venous dorsal digital flag flaps have been used for reconstruction of digital defects associated with exposure of bone or tendon in 12 patients. Satisfactory results were obtained in all cases.

Adolescent↗

PubMed1997

[Applied anatomy of the vessels in the dorsum of the finger].

Twenty adult cadavers were used to study the vessels of the flag flap in the dorsum of the finger with careful dissection and measurement. The results indicate: 1. The main blood supply to the dorsum of the finger comes from the cutaneous branches of the proper palmar digital artery. The dorsal digital artery is short and small, taking part in the blood supply of the dorsal digital skin of the proximal phalanges. 2. The veins communicate with each other, forming the first, the second and the third venous arch at the level of the distal phalangeal joint, the proximal phalangeal joint and the middle of the proximal phalanges. 3. The third venous arch is big. Proximally, the veins grouped to form radial and ulnar trunks, which communicate with the dorsum veins. 4. There are almost no veins in the area between the radial and ulnar venous trunk, which might be called the "vein lacking area." 5. The venous trunk, radial or ulnar, locates 4.1 +/- 0.1 mm from the midline of the finger dorsum at the middle of the proximal phalanges, and 5.2 +/- 0.2 mm at the metacarpophalangeal joint. Based on the results, we described the anatomical characteristics, the principle of design and the survival mechanism of the flag flap.

Adult↗

PubMed1997

[Mast cells in the labial cancer: histochemical and electron microscopical study].

The labial cancer tissue of 24 cases and normal labial tissue of 7 cases were studied histochemically and electron microscopically. The result showed that the number of mast cells around the periphery of labial cancer tissue increased significantly. The histochemical properties of these mast cells differed from those in the normal labial tissue. The former did not contain heparin which was present normally. Under electron microscope, according to the characteristic ultrastructure, the mast cells around the labial cancer were TC mast cells. Some of them showed the appearance of degranulation, and contacted intimately with cancer cells, lymphocytes and macrophages, etc. These findings suggest that together with lymphocytes, macrophages, these mast cells contribute to the defence reaction to the cancer tissue.

Cell Degranulation↗

PubMed1997

[Antibacterial activity of histidine-rich polypeptides in human parotid saliva].

Two ultrasensitive antibacterial assays were applied to determine the antibacterial activity of histidine-rich polypeptides (HRPs) in human parotid saliva. The results not only confirmed the potent antibacterial activity of HRPs against Streptococcus mutans MT6R, but also showed for the first time that HRPs were effectively antibacterial to Staphylococcus aureus ATCC 25923, Escherichia coli ML-35p and Pseudomonas aeruginosa ATCC 27853. Among HRPs, HRP3, HRP5 and HRP6 were the major antibacterial components which were active against S. mutans, S. aureus, E. coli and P. aeruginosa, whereas HRP1 was only effective against E. coli. S. sanguis was resistant to the action of HRPs. These results suggest that HRPs are actually a family of endogenous antibiotic peptides with broad antimicrobial spectrum including fungi, Gram-positive and Gram-negative bacteria and may play an important role in the prevention of various infection diseases in the oral cavity as well as in the resistance to caries.

Escherichia coli↗

PubMed1997

[Effect of human neutrophil defensins on subgingival flora].

40 teeth of 18 patients with moderate or severe adult periodontitis were examined for evaluating the effect of defensins on subgingival flora. The period of experiment was 11 days. Defensins fibers were put in the periodontal pockets deeper than 5 mm for 3 days and discarded on the fourth day. Each of the pockets was applied one fiber containing about 8 micrograms defensins. The clinical parameters (GI,BI) and the density of subgingival flora were reduced (P < 0.05). The increase of coccoid cells, and the decrease of spirochetes and rods were indicated in the relative ratio (P < 0.05). This study indicated that defensins could reduce the density of the subgingival flora and change their ratio towards the periodontal healthy flora level.

Adult↗

PubMed1997

[Investigation on the elimination of organic substances in urine by supercritical water oxidation].

Application of Supercritical Water Oxidation (SCWO) to processing of human metabolic wastes of Controlled Ecological Life Support System was studied for organic substance elimination in urine and recover potable water. The SCWO of simulated urine was investigated with oxygen as the oxidant at 400-500 degrees C and 24-30 MPa in a continuous flow reactor. The organic substance elimination efficiency was obviously effected by temperature, pressure and reaction time. It is lower than 10% at 400 degrees C, but more than 95% at 550 degrees C with reaction time of 2 min.

Ecological Systems, Closed↗

PubMed1997

[Studies on the pharmacognosy of Cortex Illicii and its adulterants].

The traditional Chinese Medicine Cortex Illicii and its adulterants were studied on textual identification, botanical origin, morphological and histological characters. The TLC and UV spertra methods were established to separate and estimate Difengpin, Magnolol and beta-sitosterol in Cortex Illicii and its products.

Chromatography, Thin Layer↗

PubMed1997

[A seroepidemiological survey: antibody to HTLV-1 in sera from various populations in Guangdong Province].

A seroepidemiological survey of HTLV-1 infection in Guangdong Province was reported. 2224 serum samples from various populations were collected and antibodies to HTLV-1 in sera were detected with indirect immunofluorescent assay. Total seropositive rate was 1.57% (35/2224). The antibody positive rates of HTLV-1 in sera from healthy individuals (n = 1810), blood donors (n = 248), patients with T cell leukemia (n = 109) and patients with neurological diseases (n = 57) were 1.27%, 0.40 %, 7.30% and 5.26% respectively. There was a significant difference between the patients with T cell leukemia and the healthy individuals (P<0.005).

Antibodies, Viral↗

PubMed1997

[HBsAg autologous red cell agglutination assay].

Three lot of HBsAg autologous red cell agglutination kits (ARCA kit) have been qualified in lab, clinical trial and the stability confirmation have been performed. The sensitivity of the kits is 1ng/ml HBsAg. A, B, O, AB type of peripheral blood or antiagglutinated specimens can be used for assay. No Holk effect has been found. The repeated rate of 10 samples assayed for five times reached 100%. The specimens collected from HAV, HCV, Schistosoma Japonicum infected patients or RF positive patients do not interfere the test. The specificity of the kits is very high. 1712 clinical specimens were inspected comparing with the EIA kits in market. The relativity between the two methods is 0.985. 18 of the 26 specimens which two methods did not accord with each other have been confirmed. The false positive and missing detected for ARCA kits is 1, 3 and for EIA kits are 6, 8 respectively. ARCA kits are stable in 4 degrees C and 22 degrees C for more than one year. The kits can stand in 35 degrees C, 45 degrees C for 45 and 10 days without losing activity respectively.

Hemagglutination Tests↗