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Biomedical subjects

D Lu

Publications and source records attributed to D Lu.

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

Distribution of two HIV-1-resistant polymorphisms (SDF1-3'A and CCR2-64I) in East Asian and world populations and its implication in AIDS epidemiology.

Chemokine receptor CCR2 and stromal-derived factor (SDF-1) are involved in HIV infection and AIDS symptom onset. Recent cohort studies showed that point mutations in these two genes, CCR2-64I and SDF1-3'A, can delay AIDS onset > or = 16 years after seroconversions. The protective effect of CCR2-64I is dominant, whereas that of SDF1-3'A is recessive. SDF1-3'A homozygotes also showed possible protection against HIV-1 infection. In this study, we surveyed the frequency distributions of the two alleles at both loci in world populations, with emphasis on those in east Asia. The CCR2-64I frequencies do not vary significantly in the different continents, having a range of 0.1-0.2 in most populations. A decreasing cline of the CCR2-64I frequency from north to south was observed in east Asia. In contrast, the distribution of SDF1-3'A in world populations varies substantially, and the highest frequency was observed in Oceanian populations. Moreover, an increasing cline of the SDF1-3'A frequency from north to south was observed in east Asia. The relative hazard values were computed to evaluate the risk of AIDS onset on the basis of two-locus genotypes in the east Asian and world populations.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Y-Chromosome evidence for a northward migration of modern humans into Eastern Asia during the last Ice Age.

The timing and nature of the arrival and the subsequent expansion of modern humans into eastern Asia remains controversial. Using Y-chromosome biallelic markers, we investigated the ancient human-migration patterns in eastern Asia. Our data indicate that southern populations in eastern Asia are much more polymorphic than northern populations, which have only a subset of the southern haplotypes. This pattern indicates that the first settlement of modern humans in eastern Asia occurred in mainland Southeast Asia during the last Ice Age, coinciding with the absence of human fossils in eastern Asia, 50,000-100,000 years ago. After the initial peopling, a great northward migration extended into northern China and Siberia.

Africa↗
PubMed1999

Evidence for production of a new lantibiotic (butyrivibriocin OR79A) by the ruminal anaerobe Butyrivibrio fibrisolvens OR79: characterization of the structural gene encoding butyrivibriocin OR79A.

The ruminal anaerobe Butyrivibrio fibrisolvens OR79 produces a bacteriocin-like activity demonstrating a very broad spectrum of activity. An inhibitor was isolated from spent culture fluid by a combination of ammonium sulfate and acidic precipitations, reverse-phase chromatography, and high-resolution gel filtration. N-terminal analysis of the isolated inhibitor yielded a 15-amino-acid sequence (G-N/Q-G/P-V-I-L-X-I-X-H-E-X-S-M-N). Two different amino acid residues were detected in the second and third positions from the N terminus, indicating the presence of two distinct peptides. A gene with significant homology to one combination of the determined N-terminal sequence was cloned, and expression of the gene was confirmed by Northern blotting. The gene (bvi79A) encoded a prepeptide of 47 amino acids and a mature peptide, butyrivibriocin OR79A, of 25 amino acids. Significant sequence homology was found between this peptide and previously reported lantibiotics containing the double-glycine leader peptidase processing site. Immediately downstream of bvi79A was a second, partial open reading frame encoding a peptide with significant homology to proteins which are believed to be involved in the synthesis of lanthionine residues. These findings indicate that the isolated inhibitory peptides represent new lantibiotics. Results from both total and N-terminal amino acid sequencing indicated that the second peptide was identical to butyrivibriocin OR79A except for amino acid substitutions in positions 2 and 3 of the mature lantibiotic. Only a single coding region was detected when restriction enzyme digests of total DNA were probed either with an oligonucleotide based on the 5' region of bvi79A or with degenerate oligonucleotides based on the predicted sequence of the second peptide.

Amino Acid Sequence↗
PubMed1999

A mutation in the insulin 2 gene induces diabetes with severe pancreatic beta-cell dysfunction in the Mody mouse.

The mouse autosomal dominant mutation Mody develops hyperglycemia with notable pancreatic beta-cell dysfunction. This study demonstrates that one of the alleles of the gene for insulin 2 in Mody mice encodes a protein product that substitutes tyrosine for cysteine at the seventh amino acid of the A chain in its mature form. This mutation disrupts a disulfide bond between the A and B chains and can induce a drastic conformational change of this molecule. Although there was no gross defect in the transcription from the wild-type insulin 2 allele or two alleles of insulin 1, levels of proinsulin and insulin were profoundly diminished in the beta cells of Mody mice, suggesting that the number of wild-type (pro)insulin molecules was also decreased. Electron microscopy revealed a dramatic reduction of secretory granules and a remarkably enlarged lumen of the endoplasmic reticulum. Little proinsulin was processed to insulin, but high molecular weight forms of proinsulin existed with concomitant overexpression of BiP, a molecular chaperone in the endoplasmic reticulum. Furthermore, mutant proinsulin expressed in Chinese hamster ovary cells was inefficiently secreted, and its intracellular fraction formed complexes with BiP and was eventually degraded. These findings indicate that mutant proinsulin was trapped and accumulated in the endoplasmic reticulum, which could induce beta-cell dysfunction and account for the dominant phenotype of this mutation.

Alleles↗
PubMed1999

[HLA-DQA1 genes involved in the genetic susceptibility to duodenal ulcer in Wuhan Hans].

OBJECTIVE: To study the genetic susceptibility of HLA-DQA1 alleles to duodenal ulcer in Chinese Hans from Wuhan and its nearby regions. METHODS: Seventy patients with duodenal ulcer and fifty healthy controls were examined for HLA-DQA1 genotypes. HLA-DQA1 typing was carried out by digesting the locus specific polymerase chain reaction amplified products with alleles specific restriction enzymes (PCR-RFLP), Apal I, Basj I, Hph I, Fok I, Mbo II and Mnl I. RESULTS: The allele frequency of DQA1 0301 in patients with duodenal ulcer (64.3%) was significantly higher than that in healthy controls (36%). In contrast, the allele frequency of DQA1 0102 in patients with duodenal ulcer (8.6%) was significantly lower than that in healthy controls (26%). CONCLUSION: These findings suggest that DQA1 0301 is a susceptible gene for duodenal ulcer in Wuhan Hans while DQA1 0102 is its resistant gene, and there are immunogenetic differences in HLA-DQA1 locus between duodenal ulcer patients and healthy controls.

Adolescent↗
PubMed1999

[Linkage analysis of chromosome 5 and asthma in a Chinese population].

OBJECTIVE: To investigate the linkage between asthma and 5q31-33 in a Chinese population. METHODS: The linkage between microsatellite markers in 5q and asthma and allergy was tested by lod score analysis. RESULTS: The linkage between asthma and 5q31-33 was not confirmed. CONCLUSION: The genes at 5q31-33 are not likely to contribute to inheritance of asthma in this Chinese population.

Asthma↗
PubMed1999

An experimental investigation of osseointegration and stability of implants used as orthodontic anchorage in dogs.

OBJECTIVE: To investigate osseointegration and stability of three kinds of implants used as orthodontic anchorage in dogs. METHODS: HA-coated, titanium plasma-coated, and uncoated titanium implants were inserted into each femur of two dogs. After a healing period of three months, orthodontic force of 200 g was applied by means of Ni-Ti springs which were connected to the two adjacent implants for two months. Position change of the implant was first measured and then calculated. The shear bond strength of the interface between implant and bone was measured with a push test. After the test, the fracture surface at the interface was observed with a scanning electronic microscope. RESULTS: All implants were stable, without mobility. The highest bond strength and mature bone compactness were found at the interface between HA-coated implant and bone. The other two showed no significant difference in bond strength. However, osseointegration existed at the interface between all three kinds of implants and bone. CONCLUSION: HA-coated, titanium plasma-coated, and uncoated titanium implants can each serve as orthodontic anchorage as well as prosthodontic abutment.

Animals↗
PubMed1999

[Study on the pathogenesis of acquired pure amegakaryocytic thrombocytopenic purpura].

OBJECTIVE: To investigate the possible pathogenesis of acquired pure amegakaryocytic thrombocytopenic purpura(APATP). METHODS: Twenty eight patients with APATP were studied. Bone marrow mononuclear cells(MNCs) from these patients were plated into methyl cellulose cultures for CFU-GM, CFU-E and CFU-MK assay. The influence of depleting T cells or adherent cells from patients' marrow cells on CFU-MK growth was observed. The humoral inhibitory effect on CFU-MK was determined by co-incubation of patients' sera or IgG with normal or autologous MNCs prior to cultures. The serum MK-CSA was also assessed. RESULTS: Fifteen cases (53.6%) of APATP was resulted from intrinsic defect of CFU-MK. The megakaryocyte colony formation was augmented significantly in 3 T lymphocytes-depleted and 2 mono-macrophages depleted patients. Sera from 6 patients(21.4%) were inhibitor to CFU-MK. The inhibitor originated from IgG and selectively directed against the megakaryocyte. In the remaining 2 cases, the pathogenesis was not ascertained. CONCLUSION: The intrinsic defect of megakaryocyte progenitor cell is considered to be a primary pathogenesis of APATP. In some patients the disease can result from abnormal immune mechanisms. The decompensation of MK-CSA production could also be an important cause for APATP.

Adolescent↗
PubMed1999

[Prophylaxis and treatment of cytomegalovirus infection in allogeneic bone marrow transplantation].

OBJECTIVE: To assess the efficacy and safety of Cymevene (ganciclovir) in the prophylaxis and treatment of cytomegalovirus (CMV) infection after allogeneic bone marrow transplantation (allo-BMT). METHODS: Sixty patients with leukemia undergoing allo-BMT were observed. Cymevene was given prophylactically to 20 patients at a dose of 5 mg/kg twice daily from day -9 to day -2 and restarted when the ANC > or = 1.0 x 10(9)/L and BPC > or = 30 x 10(9)/L at a daily dose of 5 mg/kg for 5 days every week until day +100. In diagnosed symptomatic CMV infections, the dose of Cymevene was 5 mg/kg twice daily for 2-3 weeks followed by 5 mg/kg twice a day for 5 days every week for an additional 2-3 weeks. RESULTS: The incidence of active CMV infection was 0 in the prophylaxis-treated patients and 25% in the controls (P < 0.05). In diagnosed CMV diseases, marked improvement was noted in 17 of 20 patients (85%) treated with Cymevene. The most common adverse events of Cymevene were leukopenia and thrombocytopenia, but were reversible. CONCLUSION: Cymevene is effective and safe for the prophylaxis and treatment of CMV infections after allo-BMT.

Acute Disease↗
PubMed1999

Comparison of some antineoplastic drugs on inhibiting thrombin catalizing fibrinogen clotting in vitro.

OBJECTIVE: To classify the effect of thrombin, the key enzyme which enables fibrinogen to form fibrin (fibrinogen clotting) on the formation of metastasis by comparing the inhibition of some antineoplastic drugs on fibrinogen clotting in vitro. METHODS: Time intervals of different drugs to reach a maximum OD (340 nm) data in fibrinogen solution added with thrombin were used in this work. RESULTS: It was found that L-4-oxalysine (8-40 micrograms/ml) and arabinosyl cytosine (10-50 micrograms/ml) could inhibit the effect of thrombin by extending the fibrinogen clotting time to 100%-150% (P < 0.001) and 61%-100% (P < 0.001) while the other antimetastatic drugs razoxane, probimane, adriamycin, harringtonine homoharringtonine and alpha-anordrin at the treatment concentrations showed no such activity. The positive rate of drugs to thrombin activity was approximately 25%. CONCLUSION: It suggests that L-4-oxalysine and arabinosyl cytosine may even exhibit antimetastatic effect through thrombin-fibrinogen pathway, and thrombin might operate in tumor metastasis for only limited step but crucial to fibrin formation in tumor nodules.

Amino Acids, Dicarboxylic↗
PubMed1999

[Efficacy of Chinese recipes of replenishing kidney and activating blood circulation in female rats with osteoporosis induced by ovariectomy].

OBJECTIVE: To investigate the efficacy of Chinese recipe of replenishing Kidney and activating blood circulation (RKABC) in female rats with osteoporosis induced by ovariectomy. METHODS: Fifty female SD rats at 12 months of age were chosen, and were divided into 5 groups; control, model, model plus nylestriol, RKABC (high dose) and RKABC (low dose). The model of osteoporosis was established by ovariectomy in rats for 12 weeks, and then was given different kinds of liquid and administered approximately for 12 weeks. General bone mineral density (GBMD), femur bending strength (FBS), serum-BGP and urine-Hyp/Cr were measured. RESULTS: GMBD, FBS in 3 treatment groups were significantly higher than those in the model group (P < 0.05), but lower than those in the normal control group (P < 0.05); GBMD, FBS in 2 RKABC groups were slightly higher than those in nylestriol's group (P > 0.05). Compared with model group, levels of serum BGP in 2 RKABC groups increased (P < 0.05) and in RKABC (H) treatment group increased almost the same as those in the control group (P > 0.05). In comparison with model group, levels of U-Hyp/Cr in 3 treatment groups decreased (P < 0.05, P < 0.01) but 2 RKABC treatment groups still significantly higher than those in the normal control group (P < 0.05). CONCLUSION: It indicated that RKABC could control osteoporosis in female rats induced by ovariectomy and seems to promote bone formation.

Animals↗
PubMed1999

[Effect of running granule on repairing capacity of neuro-endocrine-immunity and DNA in treating mastoplasia].

OBJECTIVE: To explore the clinical effect and therapeutic mechanism of Runing Granule (RNG) in treating mastoplasia to elucidate its pathogenesis. METHODS: One hundred and eighty-seven patients suffering from mastoplasia were randomly divided into the RNG treated group (treated group, 147 cases), and the tabellae tamoxifen control group (control group, 40 cases). The follow-up underwent for 3 months. Before and after treatment, changes of levels of plasma neurotransmitters, serum endocrine hormone, peripheral lymphocyte unscheduled DNA synthesis, the count of T lymphocyte subsets in the luteal phase during the menstrual cycle of 104 cases were measured, their clinical effects were also observed. RESULTS: Before treatment, these cases showed disturbances in the secretion of 5-hydroxytryptamine (5-HT), epinephrine (E), estradiol (E2), follicle stimulating hormone (FSH), luteinizing hormone (LH), and the levels of norepinephrine (NE), prolactin (PRL), inducer-helper T lymphocytes (OKT4+), suppressor T lymphocytes (OKT3+), were significantly increased, progesterone (P), testosterone (T), total T cells (OKT3+), OKT4+/OKT8+ ratio, unscheduled DNA synthesis (UDS) were obviously reduced (P < 0.05, P < 0.01) in mastoplasia patients. After treatment, RNG showed regulation on disturbances of these parameters, the curative rate of the treated group was higher than that of the control group; the metabolic disturbances of 5-HT/NE, E2/P, T, OKT3+ in the treated group were improved more significantly than those in the control group (P < 0.05). During the period of clinical observation, no obvious side effect and toxicity of RNG were found. CONCLUSIONS: Mastoplasia is caused by the interactions among multi-factors in which the neuro-endocrine-immune network plays a key role in the pathogenesis of mastoplasia. RGN was effective in treating mastoplasia, the mechanism probably lays on the regulation of comprehensive coordination from the multi-layers, multi-links and multiple pathways in the neuro-endocrine-immunity network and elevation of internal environment-stabilizing capacity of the body.

Adult↗
PubMed1999

[A study of mitoxantrone with other chemical agents in treating 126 cases of adult acute myeloid leukemia].

OBJECTIVE: To estimate the effect of mitoxantrone with other chemical agents in treating adult acute myeloid leukemia. METHODS: 126 inpatients diagnosed as acute myeloid leukemia between January 1993 to December 1997 were treated with mitoxantrone with other chemical agents. 85 had not been treated previously, (untreated) while 51 were relapsing or resistant to previous treatment. RESULTS: The complete response rate among untreated and the relapsing/resistant groups were 44.7% and 27.5%; while the partial response rate were 20.0%, 9.8% respectively. 4 patients were in the untreated group died early. The main side-effect of mitoxantrone is bone marrow depression which led to fever and bleeding with rates of 40.4%, 24.3%. The non-bone marrow side-effects were tolerable. Damage to the liver was a prominent occurrence 31.8%. CONCLUSION: mitoxantrone was effective as the first line anti-tumor drug with other chemical agents in treating adult acute myeloid leukemia, its side-effects were mild.

Adolescent↗
PubMed1999

[A clinico-pathological study of granulomatous amoebic encephalitis].

OBJECTIVE: To study the clinico-pathological characteristics and differential diagnosis of granulomatous meningioencephalitis caused by acanthamoeba. METHODS: The clinical features, CT scan findings and post mortem pathological changes of 3 patients afflicted with granulomatous amoebic encephalitis (GAE) were analysed. RESULTS: GAE is a chronic clinical entity. Clinical manifestations include headache, low fever, seizures, hemiparesis and coma leading to death. CSF: pressure slightly elevated with presence of lymphocytes and plasma cells, glucose usually low with moderately high protein levels. CT scans were non specific. Clinical course insidious and may mimic bacterial meningitis or tuberculous meningitis. Post mortem pathological examinations showed that acanthamoeba produced a chronic or subacute granulomatous meningioencephalitis. Acanthamoebic trophoziotes and cysts were found within the hemorrhagic necrotic cerebral tissues. In some cases there is severe angitis and fibrinoid necrosis of the vascular wall with perivascular cuffing by lymphocytes and plasma cells. Trophozoites and cysts were found within the perivascular space. CONCLUSIONS: Acanthamoeba is an opportunistic pathogenic free living amoeba which can produce fatal GAE.

Acanthamoeba↗
PubMed1999

[The examination of SIgE in perennial allergic rhinitis with mast allergy test system].

OBJECTIVE: To explore the relation between serum specificity immunoglobulin E (SIgE) and skin test (intracutaneous test) as well as nasal provocation in Perennial allergy rhinitis (PAR) by Mast Allergy Test System. METHOD: Serum allergen-specific IgE (SIgE) were examined by Mast Allergy Test System in 57 case of PAR patients. RESULT: The SIgE positive rate of fannae and pteronvssinus are highest (52.6%), the sensitive rate of intracutaneous test is 88.4% and nasal provocation is 88.9%. The SIgE positive rates of cludosporium, penicillum and altemana are 26.3%, 24.6% and 21.0%, respectively. The SIgE positive rates of fannae, cockroach, shrimp, crab, egg and milk is direct proportion with intracutaneous test (P < 0.01). Pteronvssiaus and pigweek mix have no relationship with intracutaneous test (P > 0.05). In addition, the positive rate of ragweed mix SIgE is 22.8%, but there is non of this plant in South China. It is worthy of paying attention in clinic. CONCLUSION: It indicate that Mast Allergy Test System is one of the better examination for PAR allergens.

Adolescent↗
PubMed1999

[Determination of mercury in food by microwave oven digestion-hydride generation atomic absorption spectrometry].

Mercury in food was determined by microwave oven digestion-hydride generation atomic absorption spectrometry. The best condition of digestion was also studied. Furthermore, the way of doing digestion was compared to standard method with satisfactory results. The method is rapid and simple, and of good precision and high accuracy. The sensitivity is 0.43 microg/L. The detection limit is 0.35 microg/L. The relative standard deviation is 2.8% and the recovery is 93.5%-103.0%.

Food Analysis↗