Preparation and radiopaque properties of chitosan/BaSO4 composite fibers

Chitin and chitosan have been extensively investigated as a matrix of organic/inorganic composite. Barium, one of the radiopaque inorganic materials, can provide chitosan with radiopaque property by blending of chitosan and BaSO₄. The filtered and deaerated chitosan/BaCl₂ solutions were extruded into NaOH and Na₂SO₄ coagulation bath through a nozzle by gear pump. BaSO₄ was synthesized by the reaction between BaCl₂ and Na₂SO₄ in the coagulation bath, in which acidic chitosan solution was also solidified at the same time. In XRD, the introduction of BaSO₄ into chitosan fibers reduced the inherent peak of chitosan fibers. In angiographic observation, chitosan/BaSO₄ hybrid fibers exhibited the clear contrast images which become clear with an increase in BaSO₄ content.     

麦园蜘蛛(Penthaleus sp.)及麦长腿蜘蛛(Petrobia latens(Müller))的生物学研究

1953—1955年在晋南、北京等地对麦园蜘蛛及麦长腿蜘蛛的发生规律及生活习性进行了研究。结果明确两种麦蜘蛛一年中:秋季密度最大时期为11月上、中旬。春季密度最大的时期,麦园蜘蛛在3月下旬至4月上旬;麦长腿蜘蛛在5月上旬前后。两种麦蜘蛛均以滞育卵越夏。直至10月中旬,越夏卵始孵化,孵化最盛在11月上旬,此时幼、若虫出现最多,若进行防治可基本上防止以后的猖獗。根据结果分析,估计麦园蜘蛛每年发生2—3代,麦长腿蜘蛛发生3—4代。室内饲育初步观察麦园蜘蛛一世代(从卵到产卵)历时平均约57.8天;麦长腿蜘蛛为32.1天。两种麦蜘蛛都是单性生殖。麦长腿蜘蛛的滞育卵,具多年滞育习性,初步观察有些卵能在土中生活两年。两种麦蜘蛛的分布和猖獗都受湿度的影响,主要猖獗为害地区麦长腿蜘蛛在黄河以北的旱地;麦园蜘蛛在黄淮地区的水浇地或低洼地。耕作栽培对麦蜘蛛的发生有重要影响;连作对两种麦蜘蛛发生有利;深耕能将卵翻至深土之下,可以减少发生;晚播影响麦蜘蛛孵化后的食料。因此,合理轮作、深耕和适当晚播是综合防治中的重要措施。     

Development and functional characterization of monoclonal antibodies recognizing chicken lymphocytes with natural killer cell activity.

We have developed two monoclonal antibodies which detect cell surface antigens present on chicken lymphocytes mediating natural killer (NK) cell activity against the avian tumor cell target. The monoclonal antibodies, K-14 and K-108, stained 17 and 6% of splenic lymphocytes, and 11 and 14% of peripheral blood lymphocytes (PBL), respectively, and fewer than 5% of thymic and bursal lymphocytes. Neither of these monoclonal antibodies stained adherent macrophages or the MC29-virus transformed monocytic cell line. Both monoclonal antibodies significantly inhibited NK cell activity in a standard 4 h 51Cr-release cytotoxicity assay using the LSCC-RP9 tumor cell line as target cells at an effector to target ratio of 50:1. Pretreatment of splenocytes with either monoclonal antibody in the presence of rabbit complement (C) resulted in a significant reduction in NK cell activity. However, the monoclonal antibody K-1 which detects normal chicken macrophages did not interfere with NK cell activity. The monoclonal antibody K-108 significantly blocked Fc receptor-mediated rosette formation of sheep red blood cells coated with IgG antibodies (EA) by 56% while the monoclonal antibody K-14 did not show a significant blocking. These results indicate that the monoclonal antibodies K-108 and K-14 identify different epitopes present on the surface of chicken splenic lymphocytes which mediate spontaneous NK cytotoxicity.     

Anti‐microbial Susceptibility for east1+Escherichia coli Isolated from Diarrheic Pigs in Korea

The in vitro susceptibilities of 128 isolates of east1⁺Escherichia coli from pre‐weaned and post‐weaned pigs with diarrhoea were tested with nine commonly used anti‐microbial agents by an agar dilution minimal inhibitory concentration (MIC) procedure according to National Committee for Clinical Laboratory Standards guidelines. For the isolates from pre‐weaned and post‐weaned pigs, most of them were susceptible to low concentrations (MIC₉₀) of tetracycline (4 and 2 μg/ml), ceftiofur (2 and 2 μg/ml), and colistin (4 and 2 μg/ml). Marked resistance was found in others.     

Antiproliferative lactams and spiroenone from adlay bran in human breast cancer cell lines

Two new lactams, coixspirolactam D (1) and coixspirolactam E (2), and a new spiroenone, coixspiroenone (3), together with seven known compounds, coixspirolactam A (4), coixspirolactam B (5), coixspirolactam C (6), coixlactam (7), coixol (8), ethyl dioxindole-3-acetate (9), and isoindol-1-one (10), and two neolignans, zhepiresionol (11) and ficusal (12), were isolated from the bioactive subfraction of adlay bran ethanolic extract (ABE). Compounds 9 and 10 are the first isolates from natural resources. The structures of new compounds were identified by spectroscopic methods, including infrared (IR) spectrum, 1D and 2D nuclear magnetic resonance (NMR), and mass spectrum (MS). All of the isolated compounds were tested for antiproliferative effects on MCF-7, MDA-MB-231, and T-47D cells. Results showed that compounds 1, 3, 4, 6, and 7 at 50 μM significantly inhibited MCF-7 cell proliferation by 30.2, 19.2, 21.0, 13.5, and 32.4%, respectively; compounds 2, 4, and 7 significantly inhibited T-47D cells at 50 μM by 20.7, 24.8, and 28.9%; and compounds 1, 2, and 12 significantly inhibited MDA-MB-231 cells at 50 μM by 47.4, 25.3, and 69.3%, respectively. In conclusion, ABE has antiproliferative activities, and this effect is partially related to the presence of lactams and spiroenone.     

Dairy-cattle health in Gyeongnam, Korea.

An animal-health monitoring system in the Gyeongnam area was started in 1997 to develop statistically valid data for use in estimating disease frequencies in dairy cattle, and the associated costs. The objectives of this study were to: (1) describe what was done to implement and maintain the system in Gyeongnam; (2) present selected disease frequencies; (3) discuss the epidemiological consideration of what was done and implications for results obtained.Veterinary medical officers (VMOs), comprising professors and graduate students from Gyeongsang National University, faculty of Gyeongnam Livestock Promotion Institute and clinic veterinarians, served as data collectors. After training on current disease and management problems of dairy cattle, interview techniques, sampling methods and data-collection instruments, the VMOs participated in selection of the sample herds and data gathering. Forty (n=40) of 167 dairy herds were selected randomly using a computer-generated list of random numbers and the VMOs visited farms once in a month for 12 months to collect data about management, disease, inventory, production, preventive treatment, financial and other relevant data. Strict data-quality control devices were used. Specific feed-back was developed for the producers and data collectors.The six disorders found most frequently in cows (from the highest to the lowest) were breeding problems, clinical mastitis, birth problems, gastrointestinal problems, metabolic problems and lameness. In young stock, respiratory, multiple system, breeding and gastrointestinal problems were predominant, whereas in calves, gastrointestinal, respiratory and integumental problems predominated.     

Evidence that Cache Valley virus induces congenital malformations in sheep

An outbreak of congenital abnormalities occurred in sheep at San Angelo, Texas, between December 1986 and February 1987. Of 360 lambs born, 19.2% had arthrogryposis or other musculo-skeletal problems and hydranencephaly (AGH), and the total neonatal loss was 25.6%. In 1987, all ewes that were tested with AGH lambs had antibody to Cache Valley virus (CVV), whereas 62% of the ewes with normal lambs had CVV-specific antibody. Pre-colostral serum samples from AGH lambs had neutralizing antibody to CVV. An increase in prevalence of CVV-specific antibody, from 5% during the spring of 1986 to 63.4% during the winter of 1987, occurred during a time that included the gestation of these affected lambs, as well as a period of increased rainfall. The isolation of a CVV-related strain from a sentinel sheep in October 1987 confirmed the continued presence of this virus in the pasture where this outbreak occurred and provided a recent field strain for future studies.     

EFFECT OF METHYLCELLULOSE ON UPPER GASTROINTESTINAL QUALITY IN DOGS

This study was performed to evaluate and optimize a small bowel contrast technique using barium and methylcellulose in dogs. Ten healthy dogs underwent both a conventional upper gastrointestinal study that used only barium and a modified study that used barium and methylcellulose. The control group received 10 mL/kg of 40% barium suspension. Experimental groups were divided into three subgroups given 15 mL/kg of different viscosities (low, moderate, and high viscosity) of 0.5% methylcellulose after 4 mL/kg of 40% barium suspension. Compared with the control group, dogs receiving methylcellulose had higher-quality upper gastrointestinal studies. Moderate viscosity of methylcellulose was superior to the other methylcellulose groups. In conclusion, the use of methylcellulose is a simple and effective method for improving the image quality in an upper GI examination.     

The Exploitation of Crop Allelopathy in Sustainable Agricultural Production

Crop allelopathy may be useful to minimize serious problems in the present agricultural production such as environmental pollution, unsafe products, human health concerns, depletion of crop diversity, soil sickness and reduction of crop productivity. Several crops including alfalfa, buckwheat, maize, rice, rye, sorghum, sunflower, wheat, etc. are affected either by their own toxicity or phytotoxin exudates when their residues decompose in the soil, that show strong suppression on weed emergences. Allelopathic crops when used as cover crop, mulch, smother crops, green manures, or grown in rotational sequences are helpful in reducing noxious weeds and plant pathogen, improve soil quality and crop yield. Those crop plants, particularly the legumes, incorporated at 1–2 tons ha⁻¹ (alfalfa, buckwheat, rice by-products), which can give weed reduction and increase of rice yield by 70 and 20 %, respectively, are suggested for use as natural herbicides. Allelochemicals from allelopathic crops may aid in the development of biological herbicides and pesticides. Cultivating a system with allelopathic crops plays an important role in the establishment of sustainable agriculture. The introduction of allelopathic traits from accessions with strong allelopathic potential to the target crops will enhance the efficacy of crop allelopathy in future agricultural production.