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Biomedical subjects

D Luo

Publications and source records attributed to D Luo.

At least 91 records · Page 5Linked to original sources
PubMed1997

[The effects of hypoxia on angiotensin II secretion by cultured pulmonary artery endothelial cells].

The alterations of paracrine function of pulmonary arterial endothelial cells (PAEC) might play an important role in the development of hypoxic artery hypertension (HPAH). To test this hypothesis, the effects of hypoxia on angiotensin II (AT II) secretion by new born bovine PAEC were investigated. AT II secretion increased significantly when PAECs were incubated under 2.5% O2 hypoxic condition for 1.5 h (P < 0.01 vs control). But it decreased from 1.5 h to 12 h incubation and increased from 12 h to 48 h incubation under 0% O2 hypoxic condition, with significance compared with control group (P < 0.01). NO donor SIN-1 inhibited but endogenous NO inhibitor L-nitro-arginine promoted AT II secretion significantly under both normorxic and hypoxic conditions. It was also found that the concentration of cyclic guanine monophosphate in PAEC decreased significantly at 24 h incubation in 0% O2. The above results suggest that changes of AT II in PAEC may participate in the development of HPAH.

Angiotensin II↗
PubMed1997

[Studies of mechanism of erythrocyte deformability injury during hypobaric hypoxia in rats].

Rats were randomized into sea level group and hyoxic group. Erythrocyte filtration index (IF), mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), erythrocyte [pH]i, [Mg2-]i, [Ca2+]i and [K+]i/[Na+]i were investigated in our studies. The results were as follows: 1. IF was increared in hypoxic group (0.234 +/- 0.060) 2. [Ca2+]i of hypoxic group (7.02 +/- 1.66) was evidently increased and correlated with its IF (r = 0.7386, P < 0.01), but [Mg2+]i had no obvious changes, [K+]i/ [Na+]i ratio of hypoxic group was reduced and negatively correlated with IF (r = -0.3957, P < 0.05), meanwhile, [pH] of hypoxic group increased evidently. 3. There was no statistic difference between MCHC of hypoxic and sea level group, but MCV of hypoxic group increased. These findings suggest that the changes of [Ca2+]i, [K+]i/[Na+]i ratio, [pH]i and MCV may play important role in erythrocyte deformability injury during hypoxia.

Animals↗
PubMed1997

[A study on the treatment and restoration of the complete fractured teeth].

In order to keep the fractured teeth with their important function of mastication the authors had adopted a kind of improved calvital preparation to carry out the pulp treatment for 56 cases, 63 teeth, together with periodontal washing, the application of medicine and the periodontal treatment of gingivectomy and flap operation, etc. from Jan. 1989 to Jan. 1993. The regularization of the filling of the fragmental area, the combination and the fixation of the split tooth were strengthened with spiral root post and dentin retaining nails, and then the full cast crown was restorated. The results were satisfied. It turns out that complete fracture of posterior teeth, thought to be pulled out in the past because they had split well below the gum, or even affected the pulp chamber floor, can be kept if given treatment and proper restoration.

Adult↗
PubMed1997

[A direct immunogold-silver staining method for diagnosing hemorrhagic fever with renal syndrome].

A direct immunogold-silver staining (D-IGSS) method with 5nm colloidal gold-labeled rabbit anti-HFRS IgG antibodies was employed to detect HFRS virus antigen in the cytoplasm of white blood cells from HFRS patients and compared with indirect immunofluorescence assay (I-IFA). The results showed as follows: 1. The positive rate (87.5%) of HFRSV antigen detected by D-IGSS was significantly higher than that (65.6%) detected by I-IFA. in the white blood cells (P<0.05); 2. With the D-IGSS method the positive rates of HFRSV antigen in white blood cells of finger and vein blood were 81.3% and 87.5% respectively (P>0.05) with no significant difference but finger blood smears is more simple. We belive the D-IGSS method can be widely used for early diagnosis of HFRS at basic-level hospitals.

Animals↗
PubMed1997

Testing a model of family caregivers' perceptions of elder behavior two weeks posthospitalization on caregiver response and health.

The purpose of this study was to examine the effect of family caregivers' perceptions of elders' behaviors on caregiver burden and health while controlling for other factors often associated with burden. The model tested included the following concepts: elders' health, caregivers' perceptions of elder behaviors, caregiving involvement, coping, discrepancy in social support, caregiver response and caregiver health. Data for the analyses were obtained from a longitudinal study of 346 elder/caregiver dyads in which the elders had been hospitalized for acute episodes of chronic conditions. The sample for these analyses consisted of a subset of 118 dyads from the longitudinal project. A structural equation approach using the computer software Linear Structural Relations (LISREL) was used in analyzing the data. The findings indicated that the data fit reasonably well with some of the general patterns hypothesized in the model; the Goodness of Fit Index was 0.85 and the Tucker-Lewis Fit index, .88. More important than overall fit were specific relationships. Caregivers' perception of elders' behaviors was directly linked with caregiving response two weeks postdischarge; caregiver response directly linked with caregiver health at two weeks postdischarge but not at two months postdischarge. The findings provide support for Lazarus and Folkman's theory that appraisal of the situation influences response.

Activities of Daily Living↗
PubMed1997

[Study on clinical anatomy of Chinese nasal cavity and paranasal sinus related to functional endoscopic sinus surgery].

The two-dimensional image makes it difficult to determine the anatomic locations during the Functional Endoscopic Sinus Surgery (FESS), which causes many complications. The nasal columella is the best mark to identify the distance to the operating sites during the FESS. In this study, we measured the distances and angles from the base of columella to each important landmark: the anterior end of the middle turbinate, the ethmoid bulla, the posterior and superior end of the uncinate process, the basal lamina, the posterior wall of the ethmoid sinus, the posterior and superior wall of the sphenoid sinus, the anterior and posterior ethmoid artery and the ostia of the frontal sinus and the maxillary sinus in 12 Chinese adult cadavers (24 sides). Then a simple method was proposed to identify where you are operating on and where is the most perilous point. We also paid attention to the thickness of bony wall of the optic nerve canal, the superior wall of the sphenoid sinus, the papyraceous lamina and the septa of the ethmoid air cells and found that the former two were much thicker than the latters. The thicker bony wall may contribute enough safety to the optic nerve and the hypophysis in FESS.

Adult↗
PubMed1996

Origin of floral asymmetry in Antirrhinum.

Dorsoventral asymmetry in flowers is thought to have evolved many times from a radially symmetrical ancestral condition. The first gene controlling floral asymmetry, cycloidea in Antirrhinum, has been isolated. The cycloidea gene is expressed at a very early stage in dorsal regions of floral meristems, where it affects growth rate and primordium initiation. Expression continues through to later stages in dorsal primordia to affect the asymmetry, size and cell types of petals and stamens.

Alleles↗
PubMed1996

Characterization of topoisomerase II-DNA interaction and identification of a DNA-binding domain by ultraviolet laser crosslinking.

We have used ultraviolet laser crosslinking to characterize the DNA-binding properties of highly purified yeast topoisomerase II in the absence of ATP. A single 5 ns, 20 mJ pulse of 266 nm light produced optimal crosslinking to a short DNA duplex, with an efficiency of 0.25%. An equilibrium binding constant (Keq) of 1.2 +/- 0.5 x 10(8) M(-1) was determined from kinetic analysis. Topoisomerase II showed highest affinity for supercoiled DNA. Limited proteolysis of crosslinked topoisomerase II-DNA complexes showed a site of crosslinking to be within a 29-kDa fragment with Leu-681 at its amino-terminal end. This region contains the active Tyr-783 and is homologous to the amino-terminal region of the DNA-binding bacterial gyrase GyrA subunit, suggesting a conserved DNA-binding mechanism.

Base Sequence↗
PubMed1996

Effect of prostatic growth factor, basic fibroblast growth factor, epidermal growth factor, and steroids on the proliferation of human fetal prostatic fibroblasts.

To study the relationship between androgen metabolism and the pathogenesis of benign prostatic hypertrophy, we purified a growth factor from benign hyperplastic tissue of human prostates and assayed the proliferative responses of human fetal prostatic fibroblasts to the purified growth factor (hPGF), basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), dihydrotestosterone (DHT), and estradiol (E2). Prostatic tissue extracts were fractionated using heparin-Sepharose chromatography. The fraction that eluted with 1.3-1.7 M NaCl contained the majority of mitogenic activity. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS/PAGE) of the lyophilyzed active fraction showed a band at 17,000 daltons. Human prostatic fibroblasts were isolated from fetal prostate and tested for their proliferative responses to hPGF, bFGF, EGF, DHT, and E2. hPGF, as well as bFGF and EGF, did increase tritiated thymidine incorporation into the cultured fibroblasts. DHT(10(-7) M) had a significant stimulatory effect on cell growth in serum-free media after 6 days of culture. E2(10-7 M) had no effect on cell proliferation. The combination of DHT and E2 showed no synergistic effect. We conclude that our purified hPGF, bFGF, and EGF promote cell growth directly, DHT indirectly, while E2 does not. The effect of DHT appears to be mediated via the increased production and/or secretion of growth factor(s). Possibly, the bFGF-like hPGF purified from human benign hyperplastic prostatic tissue is such a mediator.

Analysis of Variance↗
PubMed1996

The role of adhesion molecules in the recruitment of hepatic natural killer cells (pit cells) in rat liver.

Previous studies showed that blood large granular lymphocytes (LGL), which possess natural killer (NK) activity, develop within rat liver sinusoids into high-density (HD) and subsequently into low-density (LD) pit cells which show an increasing level and spectrum of tumor cytotoxicity. In this study, we investigated the role of adhesion molecules, such as CD2, CD11a, CD18, and CD54 in the recruitment of pit cells to the liver. Immunostaining for electron microscopy, and two color flow cytometry showed that most pit cells expressed CD2, CD11a, CD18, and CD54. After intravenous injections into rats with anti-CD2, anti-CD11a, and anti-CD18 antibodies, the number of pit cells per square millimeter in frozen sections of liver tissue decreased. Treatment of rats with zymosan increased the number of pit cells fivefold, whereas subsequent treatment with anti-adhesion-molecule antibodies resulted in approximately 60% lower number of pit cells. Anti-CD54, supposed to block CD54 expression on sinusoidal endothelial cells, also decreased the number of pit cells. The number of blood LGL was, however, not affected by these antibodies. These results indicate that blocking of CD2, CD11a, CD18, and CD54 antigens on blood LGL and/or liver endothelium decreased the number of pit cells in the liver. These adhesion molecules therefore play an important role in the recruitment of pit cells in the liver.

Animals↗
PubMed1996

The independent prediction of general intelligence by elementary cognitive tasks: genetic and environmental influences.

Current theories of intelligence have, in some cases, begun to include elementary cognitive tasks. Behavioral genetic studies of intelligence have not taken these theories into account. The current study includes 135 MZ and 128 DZ twin pairs from the Western Reserve Twin Project. The 11 WISC-R subtests as well as 6 elementary cognitive tasks were employed. Using a Schmid-Leiman (1957) transformation, analyses indicate a four-group factor model, supported by a second-order general factor at both phenotypic and biometric levels. Results indicate that the general factor, group factors, and specific residuals are necessary when examining additive genetic variance. Common environmental variance can be collapsed into a single general factor.

Adolescent↗
PubMed1996

Construction and expression of bi-functional proteins of single-chain Fv with effector domains.

We fused various polypeptide extensions to the C-termini of single chain Fv (scFv) and disulfide-stabilized Fv (dsFv) fragments to facilitate detection of bi-functional proteins or to add biological effector domains, which included the human metallothionein (HMT) motif and biotin mimetic sequence. These bi-functional proteins were expressed and secreted in a recombinant Pichia pastoris system and showed specific anti-idiotype binding activity, as determined by competitive radioimmunoassaying. However, the fusion protein constructed with dsFv- HMT, but not scFv-HMT, had lost this binding activity. The interruption of the structural conformation as a result in dsFv-HMT may be explained by the interactions between the cysteines engineered in dsFv domains and the cysteines in the HMT region.

Amino Acid Sequence↗
PubMed1996

Transmission imaging of large attenuators using a slant hole collimator on a three-headed SPECT system.

By combining conjugate views, truncation-free attenuation profiles of patients can be obtained by using slant hole collimators on three-headed SPECT systems. The alterations in reconstruction algorithms necessary for use with slant hole collimators and potential image artifacts are discussed. Based on an evaluation of the size of objects that can be imaged without truncation and the size of the overlap region in the conjugate views, a 15 degrees slant angle was determined to be optimal. Studies with a 30 degrees slant hole collimator verified the ability of slant hole transmission imaging to provide accurate, truncation-free attenuation maps of a 56 cm lateral width phantom. The center of rotation was determined to be dependent on the slant angle and radius of rotation of the slant collimator. These studies also demonstrated that the spatial resolution in the transaxial plane of the attenuation maps depends on radius of rotation of the slant hole collimator, but does not depend on the radius of rotation of an uncollimated transmission source. A multiline transmission source was investigated for use with estimating the attenuation map in Tc-99m labeled sestamibi perfusion imaging.

Equipment Design↗
PubMed1996

Experience in prevention of serious complications of laparoscopic cholecystectomy.

OBJECTIVE: To study the causes and prevention of the complications of laparoscopic cholecystectomy (LC). PATIENTS AND METHODS: Based on experience with 2 428 cases, the following should be paid attention to when dissecting and separating adhesions around the gallbladder and of the Calot's triangle. The best method for the prevention of mistaking the common bile duct (CBD) for the cystic duct is to find the junction of the cystic infundibulum and duct, separate the gallbladder wall along the infundibulum, and transect the cystic duct at the junction with the infundibulum. If dense adhesions around the gallbladder or of the Calot's triangle are met with, LC should be abandoned and open the cholecystectomy (OC) should be used instead. In separating the Calot's triangle, blunt dissection should be used to avoid burning the extrahepatic bile duct (EHBD), and blind hemostasis should be avoided. If the cystic artery lies in the upper part and the back of the cystic duct, the cystic duct should be dissected out, clipped and cut first, then the cystic artery be dealt with. If the cystic artery is in the front part of the pedicle of the gallbladder, the artery should be separated, clipped and cut first. Injury to the adjacent organs may be avoided by using electric coagulating hook correctly and avoiding accidental damage to the viscera, and keeping from viscera injury due to current chemotaxis in the closed cavity of the body. RESULTS: A total of 2427 patients were cured. One patient died of frequent episodes of supraventricular tachycardia and pneumonia on the 21st day after LC. CONCLUSION: If LC surgeons follow the above said principles of LC technique. LC is very safe for patients with benign diseases of the gallbladder.

Adolescent↗
PubMed1996

[Study on the organ weight of sudden death cases].

In order to make clear any influence on the weight of various organs particularly in case of chronic diseases, Basing on the result of analysis carried out previously, data of 4402 autopsy cases of sudden death collected from 22 Medical Schools and Hospitals in China were studied. The organ weight analysed included those of the heart, lungs, spleen, liver, kidneys, brain and pancreas. The results showed that weights of the heart, lungs, spleen, liver and pancrease in males and weights of the the heart, spleen and pancreas in females were heavier than those of the non-sudden death cases in adults. The difference between male and female organ weights were that weight of the female brain aged above 3 months old and weight of all the 7 organs measured in adult female were lighter than the male.

Adolescent↗
PubMed1995

Effects of methylene blue and LY83583 on neuronal nitric oxide synthase and NADPH-diaphorase.

Methylene blue and 6-anilino-5,8-quinolinedione (LY83583) have often been used as 'selective' inhibitors of soluble guanylyl cyclase. We report that in in vitro assays, both these compounds were potent inhibitors of rat cerebellar nitric oxide synthase activity. Methylene blue had an apparent Ki of 2.7 microM, while for LY83583 the Ki was 15.8 microM. Furthermore, methylene blue, but not LY83583, inhibited the NADPH-diaphorase histochemical reaction associated with nitric oxide synthase. Our results indicate that many of the effects of these drugs which have been attributed to inhibition of guanylyl cyclase, may derive from their direct inhibition of nitric oxide synthase activity instead.

Aminoquinolines↗
PubMed1995

Vl-linker-Vh orientation-dependent expression of single chain Fv-containing an engineered disulfide-stabilized bond in the framework regions.

Single chain Fv fragments (scFv) derived from an antibody, MAb 174H.64 (Tru-ScintRSQ kit, Biomira), were constructed in both orientations, i.e. Vh-linker-Vl and Vl-linker-Vh, but only the latter form could be expressed and secreted in the recombinant Pichia pastoris system. The secreted scFv protein showed specific anti-idiotype binding activity. Additionally, the molecular graphic modeling has been used to identify a possible site for the introduction of an interchain disulfide bond in the framework region of Fv. These Cys-modifications of the sites were done using a method of PCR-mediated mutagenesis. The engineered protein (disulfide-stabilized Fv: dsFv) was expressed and tested for its binding activity. It was found that dsFv was as active as the corresponding scFv and more stable as determined by competitive radioimmunoassay.

Amino Acid Sequence↗