Biomedical subjects

H Lu

Publications and source records attributed to H Lu.

At least 325 records · Page 18Linked to original sources

PubMed1997

[Tolerance limit of human upper extremity with arm restraint plate on eject seat to simulated aerodynamic loads].

To obtain tolerance limit of human upper extremity with arm restraint plate on eject seat to windblast, impact was applied to the upper extremity of 13 human corpses and 7 living monkeys by a spring driven impact device. Relationship between impact load, moment of elbow joints and arm injuries with arm restraint plate were studied. Relationship between biomechanical characteristic curve of human elbow joint and clinical injuries was obtained. The results indicated that tolerance limit of human upper arm is higher than forearm. Safety limit of human anterior arm to simulated aerodynamic load is 1.26 kN.

Aerospace Medicine↗

PubMed1997

[A simulation study on G protection using tilt-back seat].

A mathematical model of human cardiovascular system with cardiopulmonary interaction was developed basing on the previous works of Jaron, Bai jing, et al (1988, 1992). The model of pulmonary circulation was improved and intrathoracic pressure, intra-abdominal pressure and pulmonary alveolar pressure were introduced in the new model. Computer simulation experiments using this model for human relaxed tolerance to rapid onset (1 G/s), gradual onset (0.1 G/s), and high onset (5 G/s) G exposures, at seat back angles of 13 degrees, 30 degrees, 45 degrees, 55 degrees, 65 degrees, 75 degrees, and 85 degrees, were performed. The simulation results are consistent with the experimental data obtained from reported centrifuge experiments. The tolerance increase by tilt back seat may be attributed to the following three factors: (1) decrease of retinal-aorta hydrostatic distance; (2)decrease of venous pooling in the lower body; (3)decrease of G onset rate in Z axis.

Acceleration↗

PubMed1997

[Clinial study of "qingjunyin" detoxification for the treatment of heroin addicts].

To evaluate the efficacy of treatment of heroin addicts (n = 100) by "Qingjunyin" (QJY) detoxification (10 days program). Methadone detoxification (10 days program) group (n = 50) and colonidine treated group (n = 50) serve as controls. QJY group is given 180 ml P. O daily. The dosage of the two comparatine groups is given according to Documentation, the method of abserving the treatment protocols and detoxification standard is according to current regulation. The scores of abstinence syndrome in QJY detoxification group are lower than those in colonidine treated group in the first three days of potocol, but this difference disappear in the late stage of treatment. While QJY detoxification is effective as methadone detoxification in the control of abstinece syndrome during the first five days of treatment but the difference in the scores of abstinence syndrome between QJY and methadone group is observed during the late five days of protocol. QJY does not result in potential dependence and has definite curative effect in the treatment of heroin addiction.

Adolescent↗

PubMed1997

[Dynamic study of anti-NS5 and ALT in post-transfusion hepatitis C].

In order to study the character and dynamic changes of HCV NS5 antigen in post-transfusion hepatitis C, EIA was established with fusion protein, and different groups of population were investigated. The results showed the positive rate of whole blood donor, normal people, chronic hepatitis C patients and post transfusion hepatitis C patients is 0.0%, 1.66%, 50.7% and 70.5%, respectively. Serial blood samples of 25 cases of acute or chronic post-transfusion hepatitis C were detected, and the results indicated that the antibody of NS5 appeared relatively late, and the serum conversion time was 182.9 +/- 168.5 days. The anti-NS5 positive rate in 1, 3, 6, 12 and 24 months after HCV infection was 28%, 40%, 52%, 68% and 76%, respectively. The positive rate of anti-NS5 in sera with HCV RNA was 61.9%. Analysis on the appearance of antibody to the different antibody region of the gene, ALT and HCV RNA showed the dynamic changes of anti-NS5 were corresponding to the serum ALT in some cases, indicating antibody of NS5 appear later and may reflect the disease activity to some extent. The dynamic changes of anti-NS5 are of four kinds: transient positive, intermittent positive, persistent positive and persistent negative in during the two years period.

Alanine Transaminase↗

PubMed1997

[Cloning and sequencing of cDNA of E2/NS1 gene of hepatitis C virus].

Hepatitis C virus (HCV) RNA extracted from serum of a patient infected with HCV in Beijing was converted to cDNA by reverse transcription. HCV E2/NS1 gene (approximately 930 bp) was amplified by nested polymerase chain reaction and was inserted into pGEM-T plasmid vector. The 431 bp nucleotide sequence at 5' terminus of this gene was determined by dideoxy-mediated chain termination method. The result of comparison of this sequence and sequences of another 9 HCV isolates suggested that the isolate we obtained was highly homologous to HCV genotype II. There are two hypervariable regions (HVR) at the N terminus of envelope protein encoded by HCV E2/NS1 gene. Several relatively conserved amino acid residues and areas located in and out of HVR were also observed. They are concerned in maintenance of spatial conformation of HCV envelope protein, but their immune function remains to be further studied.

Amino Acid Sequence↗

PubMed1997

[Comparison of anti-hepatitis C virus (HCV) IgM and HCV-RNA detection in serum samples of patients with HCV infection].

Anti-HCV IgG is the routine assay for the diagnosis hepatitis C. But the method is ineffective in early detection of hepatitis C. We have detected anti-HCV IgM in hospital hepatitis C patients by Enzyme-Linked Immunosorbent Assay (ELISA) and compared the results with those of HCV-RNA and total antibody. Our studies indicate that anti-HCV IgM is detected in all hepatitis C marker positive sera. But the amount of anti-HCV IgM in HCV-RNA positive sera is significantly higher than that of in the corresponding negative sera. This subjects that anti-HCV IgM and HCV-RNA are somewhat correlated and they have different clinical interests. Anti-HCV IgM can be expected and hepatitis activities and its actual clinical interests are to be further studied.

Antibodies, Anti-Idiotypic↗

PubMed1997

[The study on the effect of prostaglandins A1 on the replication of human immunodeficiency virus type 1 (HIV-1) in vitro].

We observed the effect of prostaglandins A1 (PGA1) on the replication of HIV-1 by Northern-blot method in the CEM-ss cells which had been infected with HIV-1. The results showed that the RNA levels of HIV-1 in infected cells treated with PGA1 was lower than that of controls in low MOI 72-96 hours postinfection. The RNA of HIV-1 was dramatically reduced in infected CEM-ss cells when PGA1 was given 24 hours postinfection. The inhibition effect of PGA1 lasted for 9 days when PGA1 was given constantly.

Blotting, Northern↗

PubMed1997

[Liposome-mediated gene transfer into bone marrow cells and its in vitro expansion].

OBJECTIVE: To explore the efficiency of liposome-mediated gene transfer into bone marrow cells and the stability of its expression. METHODS: Two marker genes (Neo and Lac Z) mediated by liposome were co-transferred into bone marrow cells. Following G418 screening,the positive cells were enriched and expanded in vitro. RESULTS: The liposome-mediated gene transfer rate in bone marrow cells was 13.33 +/- 2.68%, and after G418 screening, it was 46.06 +/- 3.47%. The blue colouring rates with X-gal staining of these cells were not significantly different before and after expansion. CONCLUSION: Liposome-mediated gene transfer in bone marrow cells is highly efficient and the expression of the transferred gene is stable.

Bone Marrow Cells↗

PubMed1997

Renal clearance of ifosfamide.

Nephrotoxicity is an important clinical side effect of the chemotherapeutic agent ifosfamide. This medication is activated by the hepatic cytochrome P450 system with potentially toxic metabolites produced through both ring hydroxylation and chloroethyl side chain oxidation pathways. Using an isolated perfused rat kidney preparation, we examined the possibility that renal metabolism of ifosfamide also occurs. Renal function before and after addition of ifosfamide to perfusate was not significantly different. After addition of ifosfamike to the perfusate, the metabolites N2-dechloroethylifosfamide, N3-dechloroethylifosfamide, and isophasphoramide mustard were recovered from urine and renal venous effluent. These results provide the first demonstration of ifosfamide metabolism by the kidney and suggest the possibility that intrarenal metabolism may contribute to nephrotoxicity.

Animals↗

PubMed1997

[Observing and nursing of the blood circulation for the free flap].

The monitoring for the blood circulation of the free flap should be continued in postoperation. If the crisis of blood circulation occur, the monitoring for the blood circulation is the key to keep the success for the grafted flap, because the majority of the crisis of the free flap can be corrected based on the early discovering and corrective judgment. In our 11 cases, the filling of blood circulation of the free flap was difficulty to be monitored because of the pigmentation or other reason. We combined some special monitor methods to judge the blood circulation of the flap, the corrective judgment rate was 100 percent in our group. We concluded that the combined some methods for monitoring can judge the blood circulation of the flap correctly.

Blood Circulation↗

PubMed1997

Phase I clinical trial of cefditoren pivoxil (ME1207). Tolerance in healthy volunteers.

A tolerance study to ME1207 was conducted in healthy volunteers using five single doses administered before a meal (50, 100, 200, 300 and 500 mg), a single 200 mg dose administered after a meal, and 200 mg administered every 12 h for 7 days. No subjective symptoms or changes in haematological and biochemical examinations and urinalysis were observed after single administration of 50 to 500 mg Four subjects complained of minimal upper abdominal discomfort when 200 mg was administered every 12 h for 7 days, but this symptom disappeared without remedial action in all cases. Therefore ME1207 was thought to be safe when orally administered at the above-mentioned doses by the above-mentioned administration methods.

Administration, Oral↗

PubMed1997

Simulation study of the interaction between respiration and the cardiovascular system.

Many studies have been done on the respiratory and the cardiovascular system. Among them, only a few are on the interaction of these two physiologic systems. To explore the mechanism of the integration of these two physiological systems, computer simulation has been done; we report the preliminary results obtained in our laboratory. In this study, a mathematical model of the cardiovascular system integrated with the respiratory mechanical system has been established. The model is based on our previous work on cardiovascular modeling. The previous lumped lung model has been replaced by a multielement model with more detail. Interthoracic and abdominal pressures and modeled as external pressure sources on the related cardiovascular elements. Using this model, a sequence of simulation studies have been carried out. Different respiratory modes have been simulated and the different effects are observed in the simulation results. The results indicate that by following a certain respiratory pattern, the circulation status can be improved. These results agree with clinical observations.

Cardiovascular Physiological Phenomena↗

PubMed1997

Phase I clinical trial of cefditoren pivoxil (ME 1207): pharmacokinetics in healthy volunteers.

Pharmacokinetics of ME1207 were evaluated in 5 groups of healthy adult male volunteers given single preprandial administration of 100, 200 and 300 mg; postprandial administration of 200 mg; and administration of 200 mg every 12 h for 7 consecutive days. Blood drug concentrations were determined by HPLC and bioassay after oral single administration of 100, 200 and 300 mg before meals. Serum concentrations and major pharmacokinetic parameters (Cmax, Tmax, AUC and T1/2 Ke) determined by these two methods were comparable. Cmax and AUC determined by bioassay after postprandial administration were greater than those determined after preprandial administration. Blood concentrations determined 1.5 and 12 h after each administration, during repeated administration of 200 mg every 12 hours for 7 days, were always about 2.5 and 0 mg/l, respectively, indicating that the drug is not accumulated in the body. Within 24 hours after administration of 100, 200 and 300 mg, 19.93 +/- 5.20, 20.24 +/- 3.72 and 21.29 +/- 5.47%, respectively, of the dose were excreted into urine in an unchanged form.

Absorption↗

PubMed1997

Mitochondrial tRNA(Leu(UUR)) gene mutation diabetes mellitus in Chinese.

OBJECTIVE: To ascertain the prevalence and clinical features of mitochondrial tRNALeu(UUR) gene nucleotide (nt) 3243 A-->G mutation diabetes mellitus in Chinese and to establish the approaches for genetic diagnosis of this subtype of diabetes during routine daily clinical practice. METHODS: Mitochondrial nt 3243 A-->G mutation was screened among 207 unrelated non-insulin-dependent diabetes mellitus (NIDDM) patients by using polymerase chain reaction (PCR)/Apa I restriction endonuclease digestion. Samples with positive result were confirmed by DNA sequence analysis. Genetic and clinical analysis were carried out in family members of the proband with positive genetic diagnosis. RESULTS: Positive results were found in two subjects during screening of unrelated NIDDM patients, which account for 2.4%-11.1% of NIDDM subjects with uncommon clinical features (with early age-of-onset, with low body-mass-index and on insulin therapy) or with positive family history of diabetes consistent with or unable to exclude from maternal inheritance. Genetic diagnosis was positive in 10 out of 25 family members in the pedigrees of these two probands. CONCLUSIONS: Mitochondrial tRNALeu(UUR) gene nt 3242 A-->G mutation should be considered in diabetic patients with the above-mentioned clinical features. The genetic diagnosis in daily clinical practice can be performed with allele specific priming amplification, or PCR/Hae III or Apa I digestion which are technically simple to perform and diagnostically easy to define.

Adolescent↗

PubMed1997

[Morphologic changes of endometrium in patients with ectopic pregnancy].

OBJECTIVES: To study the morphologic changes of endometrium in patients of ectopic pregnancy. METHODS: The pathologic appearance of endometrium obtained during uterine curettage in 217 cases of ectopic pregnancy in our hospital were analysed retrospectively. RESULTS: Seven types of endometrial changes were observed: (1) decidua and/or Arias-Stella (A-S) reaction 147 cases (67.74%), (2) hypersecretory changes 13 cases (5.99%), (3) asynchronous secretory changes between the glands and the stroma 27 cases (12.44%), (4) partial secretory and partial proliferative changes in glands 18 cases (8.29%), a type of small A-S gland was found in 11 of them, (5) early, mid, or late secretory changes 9 cases (4.15%), (6) proliferative changes 2 cases (0.92%) and (7) glandular-cystic hyperplasia 1 case (0.46%). The above morphologic changes of endometrium were correlated with the occurrence and duration of vaginal bleeding and the urinary hCG levels. CONCLUSION: The appearance of decidua and A-S reaction should not be considered the only diagnostic basis for ectopic pregnancy. Patient's history and laboratory findings should also be taken into account in order to acquire an accurate diagnosis.

Adult↗

PubMed1997

Enhancement of Xe-133 ventilation lung scan image acquired after Tc-99m perfusion scan.

In nuclear medicine, the match and mismatch between the images of lung perfusion and ventilation provide an important criterion to diagnose pulmonary embolism. Usually, for imaging clarity, the ventilation scan using 133Xe is performed before the perfusion scan using 99mTc. But the inverse order is preferred clinically, since (i) if the perfusion image is normal, there is no need to do the ventilation scan, and (ii) if the perfusion image is abnormal, the ventilation image can be obtained by focusing on the perfusion abnormalities. However, the quality of the ventilation image is reduced if the ventilation scan is performed after the perfusion scan, because the 140 keV photons emitted from 99mTc will scatter into the acquisition window of 133Xe (81 keV). The purpose of this study is to apply image processing techniques to reduce the scattering effect of 99mTc to get a better 133Xe ventilation image. First, an image sequence in the preferred inverse order is simulated using the images acquired in the normal order. Image processing techniques are used to find an optimized way to reduce the scattering background in the ventilation image. Second, a real image sequence is acquired in the inverse order. An improved ventilation image is then obtained by applying image processing techniques to this image sequence.

Humans↗

PubMed1997

[cDNA library construction from compacted eight-cell mouse embryos and differential screening for specific-expressed cDNA clones].

A large and representative cDNA library containing 6.9 x 10(5) independent clones was constructed from about 2 x 10(3) mouse embryos at the compacted 8-cell stage to identify and characterize gene products which play crucial roles in the first differentiation process of mouse embryogenesis. The cDNA library was differentially screened with labelled cDNA probes synthesized on poly (A)+ RNA isolated from the compacted 8-cell morula or late 2-cell mouse embryos. The results showed that difference in gene expression existed between these two developmental stages. Two clones which appeared only at the 8-cell stage were selected. This study provides a valuable tool for further detailed analysis of specific proteins associated with developmental events.

Animals↗

PubMed1996

Interleukin-1 beta-converting enzyme-like protease cleaves DNA-dependent protein kinase in cytotoxic T cell killing.

Cytotoxic T cells (CTL) represent the major defense mechanism against the spread of virus infection. It is believed that the pore-forming protein, perforin, facilitates the entry of a series of serine proteases (particularly granzyme B) into the target cell which ultimately leads to DNA fragmentation and apoptosis. We demonstrate here that during CTL-mediated cytolysis the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs), an enzyme implicated in the repair of double strand breaks in DNA, is specifically cleaved by an interleukin (IL)-1 beta-converting enzyme (ICE)-like protease. A serine protease inhibitor, 3,4-dichloroisocoumarin (DCl), which is known to block granzyme B activity, inhibited CTL-induced apoptosis and prevented the degradation of DNA-PKcs in cells but failed to prevent the degradation of purified DNA-PKcs by CTL extracts. However, Tyr-Val-Ala-Asp-CH2Cl (YVAD-CMK) and other cysteine protease inhibitors prevented the degradation of purified DNA-PKcs by CTL extracts. Furthermore, incubation of DNA-PKcs with granzyme B did not produce the same cleavage pattern observed in cells undergoing apoptosis and when this substrate was incubated with either CTL extracts or the ICE-like protease, CPP32. Sequence analysis revealed that the cleavage site in DNA-PKcs during CTL killing was the same as that when this substrate was exposed to CPP32. This study demonstrates for the first time that the cleavage of DNA-PKcs in this intact cell system is exclusively due to an ICE-like protease.

Amino Acid Sequence↗