Biomedical subjects

X Yu

Publications and source records attributed to X Yu.

At least 127 records · Page 7Linked to original sources

PubMed2000

[Tolerance of various geographic populations of brown planthopper to adverse environmental stresses].

The populations of brown planthopper(BPH), Nilaparvata lugens, were collected from Zhejiang, Guangxi and Yunnan provinces to study their tolerance to various adverse environmental stresses. The results indicated that all of these three populations could adapt to the rice variety IR26 bearing resistant gene 1 (Bph1), and Guangxi and Yunnan populations could successfully infest rice varieties ASD7 bearing bph2 and Rathu Heenati bearing Bph3, implying that these two populations had a higher adaptability to resistant rice varieties. The significantly negative relationship between female brachypterous rate and nymphal density in Zhejiang population showed a lower tolerance to high nymphal density of Zhejiang population than that of Guangxi and Yunnan populations. A higher resistance to high temperature and a lower tolerance to starvation were obviously found in Guangxi and Yunnan populations. The resistance to insecticide (Omethoate) of Zhejiang population was little higher than that of Guangxi population. It was suggested that the tolerance of different geographic populations of BPH to various adverse environmental stresses be closely related to their habitat characteristics.

Animals↗

PubMed2000

[Nutrient retranslocation in fine roots of Cunninghamia lanceolata, Alnus cremastogyne and Kalopanax septemlobum in the mixed plantations--a pilot study].

Comparison of N, P and K concentrations in live and dead fine roots of Cunninghamia lanceolata, Alnus cremastogyne and Kalopanax septemlobum showed that the fine roots of A. cremastogyne had a stronger ability of N retranslocation than K. septemlobum's, but no N translocation occurred in C. lanceolata's. P retranslocation could be found in the fine roots of the all test tree species except C. lanceolata. As for K, it could translocate from fine roots to tree bodies of all these tree species before senescence. Based on the analysis on the difference of N, P, and K concentrations in live fine roots of each pair of tree species in the mixtures, it was suggested that N and K could respectively transfer from the root system of A. cremastogyne and K. septemlobum to the fine roots of C. lanceolata, and the mechanism could be clarified through exploring the ecological process of root-soil interface.

Biological Transport↗

PubMed2000

[Hunger tolerance of Microvelia horvathi hibernating generation].

The experimental results showed that the hunger tolerance (HT) of different wing forms Microvelia horvathi adults had significant difference at 14-32 degrees C, and decreased with increasing temperature, which was 32.10 and 29.58 days at 14 degrees C, and 9.46 and 7.82 days at 32 degrees C, respectively for apterous and pterygote adults. The HT of apterous adults was higher than that of pterygote ones, and females was higher than males with the same wing form. The lower the temperature, the bigger the difference. The HT of M. horvathi adults differed obviously with densities. 1 female 1 male per bottle had a higher HT than 5 females 5 males per bottle and 10 females 10 males per bottle, while no difference was found between two latter densities. The HT of the 1st instar nymphs of M. horvathi had an obvious difference at different temperatures, which was significantly higher at 14 and 20 degrees C than at 26 and 32 degrees C.

Animals↗

PubMed2000

[Distribution of interleukin-6 receptors (CD(126) and CD(w130)) on circulating lymphocytes in patients with lupus nephritis].

OBJECTIVE: To study the distribution of IL-6 receptors (CD(126) and CD(w130)) on lymphocytes in patients with lupus nephritis (LN). METHOD: The percentages of lymphocyte subsets were examined by direct two colour immunofluorescence on flow cytometry. RESULTS: (1) In active and inactive cases, the percentages of CD(+)(4) cells obviously decreased as compared with the normal controls (P < 0.01). Increased numbers of CD(+)(8) cells could be detected in LN patients (P < 0.05), especially in active cases (P < 0.01). Lymphocytes of active cases contained significantly greater percentage of CD(+)(23) cells than those of normal subjects (P < 0.05). On the contrary, the percentage of CD(+)(23) cells was statistically lower in the inactive cases than in normal subjects (P < 0.01). No significant difference in the percentages of CD(+)(126) and CD(+)(w130) cells was observed among the active, inactive and healthy groups (P > 0.05); (2) The proportion of CD(+)(4) CD(+)(126) and CD(+)(4) CD(+)(w130) cells in total lymphocytes was significantly lower in the active than in the inactive ones or normal subjects (P < 0.05; P < 0.01), whereas that of CD(+)(8) CD(+)(126) and CD(+)(8) CD(+)(w130) cells was not different among the active, inactive and normal subjects (P > 0.05). The proportion of CD(+)(23) CD(+)(126) cells and CD(+)(23) CD(+)(w130) cells augmented significantly in the active (P < 0.05), whereas it lessened in the inactive without statistical meaning as compared with the normal subjects (P > 0.05). (3) There was a positive correlation between the percentage of CD(+)(23) CD(+)(126) cells and that of CD(+)(23) CD(+)(w130) cells in total lymphocytes in the active group (r = 0.756, P < 0.05). However, no correlation between the percentage of CD(+)(23) CD(+)(126) cells and that of CD(+)(23) CD(+)(w130) cells in total lymphocytes was found in the inactive (r = 0.376, P > 0.05) or normal group (r = 0.256, P > 0.05); (4) The fraction of CD(+)(23) cells expressing CD(126) and CD(w130) was related to the SLE disease activity index (SLEDAI) and lymphopenia (P < 0.05, P < 0.005). But it was neither associated with the number of damaged organs and the degree of damage, not with that of ANA, anti-dsDNA antibody and complements (C(3) and C(4)) (P > 0.05). CONCLUSIONS: LN patients present not only B cell hyperactivity but also T cell abnormality. In active cases, there is abnormal distribution of IL-6 receptors on lymphocytes: reduced CD(126) and CD(w130) expression on CD(+)(4) cells and elevated CD(126) and CD(w130) expression on CD(+)(23) cells. Detecting the proportion of CD(+)(23) CD(+)(126) cells or CD(+)(23) CD(+)(w130) cells in total lymphocytes may serve as one of activity indexes for LN patients.

Adolescent↗

PubMed2000

Developing community health nursing skills collaboration in a culturally diverse population.

The graduate curriculum in Community Health Nursing at the University of South Alabama was revised to prepare nurses to function as a community health specialist. The revised curriculum model includes two semesters that focus on a specific population or high risk group of patients or clients. Emphasis is placed on the skills that community health nurses must have in order to assess communities, identify community needs, plan and implement interventions at the population aggregate or community level. During the first semester, or the practicum course, a community needs assessment is performed. In the internship course, the planned intervention is implemented and evaluated. The purpose of the paper is to describe the process of identifying and accessing a Cambodian population aggregate in a rural setting. The collaboration among faculty, student, preceptor, official agency, as well as lay leaders in the Cambodian community is described.

Alabama↗

PubMed2000

[A study on the epidemiology and preventive measure on epidemic haemorrhage fever in army barrack area in Shandong].

OBJECTIVE: In order to guide the army and civilians to carry out the prevention on epidemic haemorrhage fever (EHF), it's necessary to elucidate the epidemic feature of natural epidemic foci and the risk factors of EHF in the army - stationed areas. METHODS: Samples were tested by pathogenic and serologic means before data was collected and analyzed by case - control or family - control studies. RESULTS: Cases belong to house - mouse type (91.48%), field - mouse type (7.21%) and unclassified (1.31%) coexist in the stationed area. In the two types of noticed cases, no significant difference in distributions of sex, profession and ages. Most house - mouse type cases occurred in the peak time from March to June and field - mouse type in November to next February. The type of EHF virus antigen of mice and the type of serum were both accordant with their host types. Dwelling in border area, living rooms with mice, dogs raising, injury of mouth tissue, eating food contaminated by mice, and household with mice living around were more frequently seen in cases themselves and in families of the cases than in controls of both groups (P < 0.05). The mice intensity could be under control to 1.0%, if comprehensive measure on mice control can be implemented. CONCLUSIONS: The stationed area is an epidemic area mixed with both house - mouse and field - mouse types, with majority of house - mouse type. It was house - mouse type virus infection that caused the epidemic area expanded and the number of cases increased radically these years. EHF was epidemic in spring and summer season in the stationed area mainly because the infections were among family members. Food contaminated by mice or close contact with mice played an important role. Mice eradication and prevention were the leading measures to prevent EHF, from our more than ten years of experiences.

Adult↗

PubMed2000

[Investigation on natural foci of autumn-winter type tsutsugamushi disease in Shandong province].

OBJECTIVE: In order to provide basic data of tsutsugamushi disease in Shandong province, for the control and prevention of this disease in residents and army-men. METHODS: Aetiological, serological and epidemiological methods were used to investigate the natural foci of autumn-winter type tsutsugamushi disease. RESULTS: The peak of tsutsugamushi disease epidemic in Shandong province was in October with cases in this month accounted for 80% of all in a year, that showed autumn-winter type. The main reservoir hosts were Apodemus agrarius, Rattus norvegicus and Cricetulus triton, accounted for 82.87%, 85.47% and 13.04% respectively. It was confirmed that natural infection existed among Leptotrombidium (L.) scutellare, L. palpalis, L. linhuaikonense and Walchia pacifica. The main vector of transmission was Leptotrombidium scutellare. 41 strains of Rickettsia tsutsugamushi were isolated from the blood samples of patients, rodents and chigger mites but with weak toxicity. 90% of the serotypes of the strains belonged to Gilliam type. The distribution of the cases had a sporadic nature. More than 80% of the cases were young or middle aged peasants. Clinical symptoms were mild, with some differences in different areas. CONCLUSION: The natural foci type of tsutsugamushi disease in Shandong could be divided into plain and hilly types.

Animals↗

PubMed2000

[Effects of phoxim and fenvalerate on TTX-S and TTX-R sodium channels in the DRG neurons of adult rat].

OBJECTIVE: To study the joint neurotoxic effects of phoxim (Pho) and fenvalerate (Fen) on tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant (TTX-R) Na(+) currents in dorsal root ganglion (DRG) neurons of adult rat. METHODS: Whole cell patch clamp technique was used to test the effects of Pho and Fen on TTX-S and TTX-R sodium currents in DRG neurons. RESULTS: The inactivation of TTX-R sodium channel was obviously slowed down by Fen. The tau(Na) of peak currents at doses of 10, 50 and 100 micromol/L Fen and control groups were (8.10 +/- 2.41) ms, (11.78 +/- 2.76) ms, P < 0.01, (8.76 +/-1.94) ms, P < 0.05 and (6.41 +/- 1.32) ms respectively. The inactivation of TTX-R sodium channel tail currents was also significantly delayed by Fen. The tau(Na) of the tail currents at doses of 10, 50, 100 micromol/L Fen and control groups were 6.11 +/- 0.52 (P < 0.05), 7.82 +/- 0.82 (P < 0.05), 7.23 +/- 1.09 (P < 0.05) and (4.91 +/- 0.97) ms separately. As compared with TTX-R sodium channel, the TTX-S sodium channel was less responsive to Fen exposure, which only led to slowly decay TTX-S sodium tail currents. There was no any effect of Pho on the TTX-S and TTX-R sodium channels. The mixed treatment of a Pho and Fen did not show joint effect on the sodium currents. CONCLUSION: Both the peak and tail currents are changed by Fen, however, Fen has more remarkable effects on TTX-R than on TTX-S sodium channel. The combined exposure to Pho and Fen shows no joint effect on the sodium channel.

Animals↗

PubMed2000

[The changes in serum antibody level after immunization with HFRS vaccine].

OBJECTIVES: To observe the changes in serum antibody level after mass immunization with vaccine against hemorrhagic fever with renal syndrome (HFRS) and to evaluate its efficacy and effectiveness in the prevalent areas. METHODS: Healthy people aged 16 to 60 years in the villages were recruited as study subjects, excluding those suffered from HFRS previously, going out for more than nine months and those with contraindications, and were randomly allocated into immunization and control groups with 10,460 and 16,159 persons, respectively. Specific IgG antibody was determined with indirect immunofluorescent assay (IFA) and neutralizing antibody (NA) was determined with micro CPE method. RESULTS: Two weeks after the full-course immunization, sero-conversion rate for IFA reached 100% in those sero-negative before immunization, with a 95% confidence interval of 96.3 - 100.0%, and that for NA 44.4%, with a 95% CI of 22.0% - 69.0%. Geometric mean titer (GMT) were 72.1 and 4.6 for IFA and NA, respectively. Booster immunization was provided for them one year later. Positivity of IFA and NA was 28.6%, 83.3%, 75.0%, 53.1%, 22.6% and 14.8%, 55.6%, 35.0%, 31.3%, 26.0%, before booster immunization, two weeks, one year, one and a half years, two years after booster immunization, respectively. CONCLUSION: HFRS vaccine had good immunogenicity, but its duration of serum antibody sustenance was relatively short.

Adolescent↗

PubMed2000

[Expression of proliferation and apoptosis related genes in colorectal adenoma with malignant transformation].

OBJECTIVE: The effect of proliferation and apoptosis related genes of colorectal adenoma with malignant transformation and its clinicopathologic significance was studied. METHODS: p53, bcl-2, Fas, bax expression were detected immunohistochemically in 61 cases of colorectal adenoma with either mild or severe dysplasia and carcinoma. The rate of proliferation was evaluated with Ki-67 and apoptosis with TUNEL. RESULTS: The positive rates for p53 and bcl-2 protein in carcinomatous area, adenoma with severe and mild dysplasia were 67.2%, 57.4%, 19.7% and 77.1%, 80.3%, 49.2% respectively. The mean Ki-67 index and PCD index were 38.4%, 36.5%, 16.1% and 2.2%, 1.9%, 0.5% respectively. The difference of the expression of p53 protein, bcl-2 protein and Ki-67 index, PCD index in carcinomatous region and adenoma with severe dysplasia compared with mild dysplasia was statistically significant (P < 0.05). CONCLUSION: It is apparent that both apoptosis inhibition and abnormal proliferation play an important role in tumor formation. Adenoma with severe dysplasia is a lesion very close to carcinoma in nature, which possesses active tendency to become fully malignant. Detection of these proteins is important in the early diagnosis of malignant transformation of an adenoma.

Adenoma↗

PubMed2000

[Development and application of the software measuring the size of injured body surface].

A software to measure the area, length and angle of injured body surface is introduced. It is suitable for evaluating injury degrees with 2 or 3 dimension measurement. The software is developed by Visual Basic 6.0 on Windows 98 terrace, supporting digital video camera, digital camera and scanner input. It is easy to use and has been applied in more than 200 cases.

Diagnosis, Computer-Assisted↗

PubMed2000

[The study of occlusal contact areas of upper premolars and molars in the unilateral cleft lip and palate].

OBJECTIVE: Occlusal contact plays an important roll in masticatory procedure. It infers to biting force and masticatory performance. In order to analysis the oral function in UCLP, the author tested the occlusal contact areas of upper premolars and molars in UCLP. METHODS: 22 UCLP patients (male 13, female 9, permanent teeth) were selected, which had no temporomandibular joint dysfunction. All of them had received plastic surgery treatment and never received orthodontic therapy. Their occlusal contact areas of upper premolars and molars in intercaspid position were recorded by performed soft wax, and the results were managed by computer with the software of micro image analysis system. All the data were input to computer and be analyzed by statistics. RESULTS: 1. In normal people, the occlusal contact areas of upper premolars and molars had no differences in bilateral and in sexual. 2. there was no sexual difference in UCLP as that in normal group, and the occlusal contact areas in cleft side or non-cleft side had no difference yet. 3. The occlusal contact areas in UCLP were lower than that in normal people. 4. The decrease of occlusal contact areas was the most important factor to low masticatory performance in UCLP patients. CONCLUSION: After plastic surgery in UCLP, orthodontic therapy will improve masticatory contact and contribute to craniofacial esthetic and masticatory function.

Adolescent↗

PubMed2000

[Determinations and analysis of masticatory performance in unilateral cleft lip and palate].

OBJECTIVE: Masticatory function is one of the most important physical functions in craniomaxilla system. Masticatory performance is evaluated with the degree of broken dawn tested food in a limited period of time. Unilateral cleft lip and palate (UCLP) is a congenital abnormality in craniofacial growth and developing. It seriously damages face esthetics and masticatory function in UCLP patients. METHODS: 28 UCLP patients (male 17, female 11, permanent teeth) were selected, which all had received plastic operation treatments and never received any orthodontic therapy. The masticatory performance was determined by the advanced light absorbtion method and took peanuts as tested food. Meanwhile, malocclusal patterns and castings were identified in clinic. All of the data were treated with t-test and step wise-regression in statistics. RESULTS: 1. Masticatory performance of male was higher than that of female in normal people, but there was no sexual difference in UCLP. 2. Masticatory performance in UCLP was lower about 53.97% than that in normal people. 3. Different masticatory times within limited time had no effects on masticatory performance. 4. Different Patterns of malocclusion had different effects on masticatory performance. CONCLUSION: Orthodontic therapy is necessary to improve masticatory function in UCLP after plastic surgery.

Adolescent↗

PubMed2000

[A novel method for preparation of C18 ester-bond RP-HPLC packing].

RP-HPLC packings have found widespread application in the fields of biology, chemistry and pharmaceutical industry, etc. C18-bonded phase is one of the most important packing. In order to avoid using toxic and unstable chloro-containing silane as derivatization reagent, a new practical and economic procedure had been developed to prepare RP packing. Octadecyl group was bound onto YQG80, 5 microns silica (Tsingdao Oceanic Chemical Factory, particle size d.p. 5 microns) with gamma-glycidoxypropyltrimethoxysilane as coupling agent. Elemental analysis and chromatographic evaluation confirmed the feasibility of the procedure and RP behavior of the packing. After eluting with 500 column volume of mobile phase at different pH (2, 5 and 8), the column still showed good performance (> 64,000 theoretical plates/m) and stability.

Carbon↗

PubMed2000

[The modulation of type I collagen and its receptor system on biological characteristics of osteoblasts].

This paper addresses the question whether type I collagen-receptor system is necessary for the functional activity of osteoblasts. Through blocking type I collagen-receptor system by type I collagen antibody or integrin alpha 2 beta 1 antibody, the proliferation of osteoblasts was studied by cell count, the apoptosis was studied by flow cytometry, and the mRNA expressions of type I collagen, integrin alpha 2 beta 1 and osteocalcin were also detected by RT-PCR techniques. When type I collagen-receptor system was blocked, osteoblasts showed high apoptosis rate, lower growth kinetics and weak mRNA expression of type I collagen, integrin alpha 2 beta 1 and osteocalcin; the blocking effect was reversible. It suggests that type I collagen-receptor system is necessary for osteoblastic phenotype. The biomaterials for bone tissue engineering should be constructed according to the extracellular matrix of osteoblasts, which supply normal extracellular environment for osteoblasts.

Apoptosis↗

PubMed2000

[The establishment of a computerized growth prediction system].

Natural craniofacial growth plays an important role in the etiology of malocclusion. So, craniofacial growth prediction is very necessary in orthodontics. The present author have developed a new-typed computerized craniofacial growth predition system, which was designed in the general sense of craniofacial growth. According to a unique method, the system could automatically predict of craniofacial growth to different craniofacial growth pattern. It can be used as an auxilliary tool in clinical, teaching and researches in orthodontics.

Adolescent↗

PubMed2000

[Studies on biosorption of Au3+ by Bacillus megaterium].

Some characteristics of Au3+ biosorption and bioreduction by Bacillus megaterium D01 biomass were reported. The optimum pH value of Au3+ biosorption by strain D01 was 3.0. The biosorption was a rapid process, reaching 95% of the maximal capacity within the first 5 min of contact. Temperature did not affect the biosorption. The biosorptive efficiency(99.1%) and capacity (302.0 mg Au3+/g dry weight biomass) were achieved under the conditions of pH 3.0 and 30 degrees C, both concentration with an initial Au3+/biomass radio of 305 mg/g dry weight for 30 min of the contact. The D01 biomass could reduce Au3+ in the solution to Au0, Au0 on the cells surface and in the contact solution could be crystallized to different forms gold crystals, Au3+ impregnated on SiO2 and alpha-Fe2O3 could be reduced to Au0 by D01 biomass. The results of electrochemical reaction indicated that the strain D01 exhibited a high selectivity for Au3+.

Adsorption↗

PubMed2000

Preparation of anti-idiotypic antibodies specific for anti-HEL and analysis of their functional mimicry.

OBJECTIVE: This study is to investigate the functional mimicry by using anti-idiotypic antibodies of enzymes. METHODS: Monoclonal anti-idiotypic antibodies against anti-HEL (hen egg-white lysozyme, HEL) antibodies were obtained by fusion of Sp2/0 myeloma cells with spleen cells of syngeneic mice immunized with monoclonal anti-HEL antibodies against HEL's different antigenic epitopes. Then bacteriolysis of the anti-idiotypic antibodies were observed. RESULTS: Eight hybridomas strains secreting anti-idiotypic antibodies were selected and characterized. It was shown that two of eight anti-idiotypic antibodies secreted by two hybridomas (1A10C9 and 2A11C1B3) could mimic HEL catalytic activity to lyse Micrococcus lysodeikticus and that the catalytic effect of mixed anti-idiotypic antibodies of 1A10C9 and 2A11C1B3 was stronger than that of one of them, but less than HEL. CONCLUSION: The results demonstrated that the anti-idiotypic antibodies that could mimic enzyme activity existed in the idiotype network during anti-enzymatic immune response.

Animals↗