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Biomedical subjects

B Z Xu

Publications and source records attributed to B Z Xu.

15 recordsLinked to original sources
PubMed2000

[Survey of susceptibility of anopheline vectors to insecticides in a malaria mesoendemic area, Hubei Province].

OBJECTIVE: To determine the susceptibility of Anopheles anthropophagus and Anopheles sinensis to deltamethrin and DDT in an area where different counter-measures had been adopted. METHODS: The mortality of the vectors was examined by using the standardised WHO test. RESULTS: The mortality for tentative diagnostic dose in An. anthropophagus to deltamethrin were 83.8%, 83.7% and 84.7%, respectively in the areas where impregnated net had been used for 1 year or 3 years and DDT residual spraying had been carried out for 3 years, suggesting that An. anthropophagus was an initially resistant group. The LT50 were 8.69, 7.48 and 9.87 min, respectively. The mortality for tentative diagnostic dose in An. sinensis to deltamethrin and DDT were 76.5%, 57.0% and 79.0%, respectively in three survey areas, suggesting that An. sinensis was a resistant group. The LT50 were 12.0, 15.4 and 11.2 min, respectively. The mortality for tentative diagnostic dose in An. sinensis to DDT was 95.8% in impregnated net area, suggesting that An. anthropophagus was an initially resistant group. The LC50 was 0.73%. The mortality for tentative diagnostic dose in An. sinensis to DDT was 44%, suggesting that An. sinensis was a highly resistant group. The LC50 was more than 4%. CONCLUSION: A substantial use of insecticides in the rice paddy field has resulted in resistance of An. sinensis, whereas no apparent resistance of An. anthropophgus has been found.

Animals↗
PubMed1994

[Treatment of bladder cancer by Nd:YAG laser local irradiation and whole-bladder photodynamic therapy with hematoporphyrin derivative].

Twenty cases with 51 tumor foci of urinary bladder were treated by Nd:YAG laser local irradiation plus whole-bladder photodynamic therapy (PDT) with hematoporphyrin derivative (HPD). All cases were confirmed by histopathological diagnosis. Of the 20 patients, 19 were cured after one treatment (95%) and the other patient cured after 2 treatments within 40 days. On follow-up for 3-23 months, tumor recurrence occurred in 2 cases (10%) about 3-6 months after treatment. The results suggest that the PDT effect in destroying bladder tumors might be enhanced by Nd:YAG laser while the lesions escaped Nd:YAG laser irradiation could be handled by whole-bladder PDT.

Adult↗
PubMed1994

Visual evoked potential measurement by adaptive filtering.

The method of ensemble averaging (EA), commonly used to improve signal-to-noise ratio (SNR) in evoked potential measurements, loses potentially useful information regarding response variability across trials. Due to the usually low SNR, it is difficult to extract the response from individual trials. The present paper describes an adaptive signal enhancer (ASE) that is capable of tracking the variation of visual evoked potential (VEP) from trial to trial as well as improving SNR. This ASE requires two inputs: a primary input, which is the raw noise-corrupted response, and a reference input, which is designed for an optional performance of ASE. We used moving ensemble averaging (MEA) to form the dynamic reference input. Experimental results in humans show a satisfactory performance of the ASE in determining VEP to single stimulus and in tracking the temporal changes of the signal.

Algorithms↗
PubMed1994

[A clinical study on the tumor associated antigen CA50 in the monitoring of genitourinary malignancies].

The tumor associated antigen CA50 was examined in serum level of 84 patients with genitourinary malignancies, 48 patients with genitourinary benign diseases and 35 normal persons by immunoradiometric assay (IRMA). The mean CA50 value in the patients with genitourinary malignancy was much higher then that in patients with benign genitourinary diseases and that in the normal control group (P < 0.05-0.01). Taking 17 u/ml as the upper limit of normal range, the positive rates were 55% (11/20) of patients with renal cell carcinoma, 78% (7/8) in pyeloureteric carcinoma, 65% (30/46) in bladder cancer and 70% (7/10) in genital malignancies. The sensitivity of CA50 for the patients with genitourinary malignancy was 65.5% (55/84) and the specificity was 87.5% (42/48). The measurement of level of serum CA50 also could be used to monitor the clinical change and responses during the course of treatment. It might be helpful to predict the recurrence of tumor after surgical treatment.

Adult↗
PubMed1991

Visual evoked potential measurement by maximum length sequence technique.

The maximum length sequence (MLS) technique is applied to improve data collection of a clinically important long latency visual potential. Given a limited time for measuring the response and with low number of stimulus presentation, the MLS technique exceeded the conventional method of ensemble averaging in attaining a higher signal-to-noise ratio (SNR). The theoretical consideration of such improvement is developed along with the system implementation. Typical examples of the results obtained in a human subject are presented.

Algorithms↗
PubMed1991

[Breeding grass carp against mosquitoes in rice field].

In this experimental study, grass carp were bred in rice field (1.9 fish/m2) to control mosquito larvae. 78 days after treatment, the larvae population of An. sinensis and Cu. tritaeniorhynchus dropped down by 87.4% and 80% respectively. Newly hatched 1-2 instar larvae accounted for 73.3% of the larvae remained in rice field after treatment. Eighty-nine samples of fish feces taken from rice field and 10 fishes were examined for breathing syphons of mosquito larvae. Breathing syphons were found in 22 fecal samples (24.7% positive) and 3 fishes (30% positive). The average number of mosquito larvae devoured by one fish was 861.5 in 24 hours in tap water and 661 in 24 hours in water containing grass and aquatic plants. The simulated field test showed that the average number of mosquito larvae devoured by fish was 362 larvae in 24 hours. The field trial indicated that the grass carp could not only cut down the mosquito larvae population but also benefit the peasants by increasing the production of both fish and rice.

Animals↗
PubMed1988

Study and clinical application of a porcine biomembrane for the repair of dural defects.

A biomembrane was developed from pig peritoneum treated with 0.65% glutaraldehyde. This was evaluated for use as a dural substitute in an animal model and in a patient population. After being treated with the glutaraldehyde solution, the biomembrane lost its antigenicity while its collagen underwent an irreversible cross-linking reaction, causing it to become a stable nonviable polymer resistant to absorption by the host. The biomembrane was used experimentally in 43 procedures on 20 dogs and was applied clinically in 614 patients. The results demonstrated that it is an acceptable material for the repair of dural defects, with the following advantages: 1) it is nontoxic to the body and brain tissues, with minimal tissue reaction; 2) its biophysical properties facilitate watertight closure with sutures; 3) its distensibility makes it suitable for decompressive surgical dural repair; and 4) its visceral surface is extremely smooth, causing virtually no adhesions with the brain tissue while the outer surface readily heals with the subcutaneous tissue.

Adolescent↗
PubMed1987

Floating bait formulations increase effectiveness of Bacillus thuringiensis var. israelensis against Anopheles larvae.

The development and screening of floating-type bait formulations designed to improve the activity of bacterial toxins against larval Anopheles is described. Floating and spreading abilities of carrier particles (wheat flour) were compared using corn oil, lecithin, and two products yielding surface films on water (Arosurf and Liparol). Mixtures containing 1 or 5% Arosurf showed the best spreading abilities on a water surface, but strongly inhibited the ingestion of wheat flour by Anopheles albimanus larvae. Corn oil and lecithin improved spreading satisfactorily at a concentration of 5% and inhibited larval feeding by only 6-25%. To select a suitable concentration of active ingredient in formulations, Bacillus thuringiensis var. israelensis (B.t.i.) primary powder in concentrations ranging from 0.01 to 0.5% was mixed with wheat flour/corn oil mixtures and tested in quantities exceeding the gut volumes of treated larvae. Complete mortality was obtained with concentrations of 0.1% (Anopheles stephensi), 0.2% (An. albimanus), or 0.3% (An. quadrimaculatus) B.t.i. When in 175-liter containers the activity of formulations (5% corn oil, 0.2% B.t.i.) and of toxin suspensions was compared by conventional dosage-mortality regression, formulations were more active by a factor of 68 against An. stephensi, 39 against An. albimanus and 67 against An. quadrimaculatus.

Animals↗
PubMed1983

Synthesis of the 3'-half molecule of yeast alanine tRNA.

This paper deals with the synthesis of the 3'-half molecule of yeast alanine transfer RNA (tRNAAlay) by ligation with T4 RNA ligase of three component oligonucleotide fragments corresponding to nucleotides 36-45(I), 46-57(II) and 58-76(III) in succession extending from the 3'-end to the 5'-end. First, in a ratio of acceptor to donor at 1.5 to 1, we adopted a method of three successive reactions, namely, the 5'-phosphorylation of the nonadecamer (III), ligation with the dodecamer (II) and the 5'-phosphorylation of the ligation product formed; with one isolation step and obtained the 5'-phosphorylated 31mer(46-76) (IV) in an overall yield of 70%. Then the 31mer(IV) as a donor was ligated with 3 times of decamer (I) to form the 41mer(36-76) (V), the 3'-half molecule of tRNAAlay. The yield was 67%. After 5'-phosphorylation, (V) was ligated with the natural 5'-half molecule to form the semi-synthetic tRNAAlay, which was biologically active, i.e. accepting and transferring (3H)-alanine into proteins.

Base Sequence↗