Changes of regional cerebral blood flow in AIDS patients without acquired immunodeficiency syndromes dementia complex

AIM:To investigate the changes of regional cerebral blood flow(rCBF) in AIDS patients without acquired immunodeficiency syndrome dementia complex(ADC).METHODS:^99mTc-ECD brain SPECT imaging was performed in 4 AIDS patients without ADC and 16 sex and age-matched normal controls. The rCBF percentage compared to the cerebellum were calculated using a semi-quantitative processing software.RESULTS:The rCBF in the right and left frontal, temporal, porietal lobe, basal ganglia and thalamus, cyrus rectus and pons were decreased significantly in AIDS patients without ADC than those of the control subjects (P＜0.01).CONCLUSION:There is reduced cortico-subcortical rCBF in AIDS patients without ADC.     

Advances on studies of AIDS pathogenesis and new strategies for drug and vaccine development

A breakthrough has recently been made in the studies on pathogenesis of HIV disease, which result in some new theories. New strategies for HIV drug and vaccine development are emerging in the impact of these new understandings. The intestinal infection hypothesis proposes that HIV disease can be regarded as some kind of infectious disease of gut immune system as the major HIV infection is located in intestine. The acute catastrophe hypothesis suggests that the subsequent pathological changes are the fallout from a mucosal catastrophe of acute intestinal HIV infection, in which the majority of CD4+ T cells are deleted due to infection. The general immune overactivation hypothesis proposes that the general immune overactivation is harmful to patient as it increases the cell susceptibility to HIV infection and supportiveness of HIV replication. The host proteins related to HIV replication can be new targets for HIV drug discovery. The mucosal vaccine strategies, which attempt to induce HIV specific neutralizing antibodies on mucosal surface may be the first choice in development of prophylactic HIV vaccines. Induction of tolerance may be one of the strategies for HIV therapeutic vaccines because HIV disease can be regarded as autoimmune disease caused by HIV infection.     

Emergence of Phaseolus Vulgaris Seedlings from Wet Soil

The failure of Phaseolus vulgaris seedlings to emerge when irrigated after seeding was found to be caused mainly by mechanical impedance of the wet soil and not by soaking injury. Seeds sown deeper than 2-5 cm and then irrigated produced abnormal seedlings with thickened, flattened and hollow hypocotyls. In addition, such seedlings often sustained damage such as the loss of a cotyledon or the breaking of the hypocotyl. Seeds soaked in 1% hydrogen peroxide, which is known to prevent soaking injury and to promote seedling growth in germination boxes, emerged poorly in soil, presumably due to bruising of the water-saturated cotyledons while pushing through the soil. Satisfactory emergence can be obtained, however, from seeds sown 2-5 cm deep and then irrigated provided the soil is not allowed excessively either to dry out or become heated by solar radiation.     

Effect of Fu-Sheng powder on ischemia-reperfusion-like injury in neural cells

AIM: To further elucidate the mechanism underlying the protective effect of Chinese herb Fu Sheng powder on vascular dementia. METHODS: Primary passage of neural cells of new born rats were subjected to the ischemia-reperfusion-like injury of hypoxia plus glucose deprivation followed by reoxygenation plus glucose, and the effect of "Fu-Sheng powder" on neural cells was examined. RESULTS: Both 5 hours of "ischemia" and 5 hours of "ischemia" plus 5 hours of "reperfusion" led to severe injury to neural cells, the formation of MDA and intracellular calcium concentration increased significantly, however, the activities of SOD and fluidity of neurons decreased significantly. It was also observed that Fu-Sheng powder could significantly alleviate this injury. CONCLUSION: Fu-Sheng powder had direct protective effect on neurons subjected to iscehmia-reperfusion-likeinjury, which might be one of the mechanisms underlying its therapeutic effect on vascular dementia.     

Rapamycin promotes repair of neurovascular units after ischemic stroke

Neurovascular unit （NVU） is composed of neurons, endothelial cells, pericytes, astrocytes, macrophages/microglia, smooth muscle cells, extracellular matrix, etc, and plays vital roles in maintenance of the normal brain tissue function and cellular homeostasis. Cerebral ischemia caused by stroke can harm various components of NVU. Repairing damaged NVU and maintaining its structural and functional integrity are an effective way to improve stroke treatment. Resent research has found that rapamycin not only enhances autophagy of neurons but also effectively repairs the injuried components of NVU , thereby reducing neural damage after stroke. In this paper, the mechanisms of rapamycin underlying the repair of injured NVU after ischemic stroke is reviewed to provide guidance for its application in the treatment of stroke.     

Calcium-influx response and ERK phosphorylation in human microglia triggered by HIV-1 glycoprotein gp120

AIM: The aim of the present study is to explore the effects and mechanisms of HIV-1 glycoprotein gp120 on calcium-influx and ERK-phosphorylation of human microglia.METHODS: The level of intracellular calcium of human microglia grown on coverslip,which was loaded by calcium-probe,Fluo-4,and then treated in various experimental processing,was detected by confocal microscopy with time resolution mode.The binding of gp120 to human microglia was determined with confocal microscopy or flow cytometry after treatment with gp120 and stained with anti-gp120-FITC antibody.Phosphorylation of ERK within human microglia with or without gp120 stimulation was analyzed with confocal microscopy following the direct immuno-staining with anti-phosphorylated ERK antibody.RESULTS: The results of confocal microscopy showed that calcium-influx response was triggered by HIV-1 glycoprotein gp120 in human microglia.The results from analysis by confocal microscopy and flow cytometry showed that gp120 was able to bind to human microglia.ERK phosphorylation was enhanced in human microglia stimulated with gp120.CONCLUSION: HIV-1 glycoprotein gp120 induces calcium-influx in human microglia and enhances ERK phosphorylation in human microglia,indicating that gp120 is an activator of human microglia.So gp120 may be involved in the pathogenesis of HIV-associated dementia.     

Physical influences of landscape on a large-extent ecological disturbance: the northeastern North American ice storm of 1998

The 1998 ice storm was a large-extent ecological disturbance that severely affected the eastern Adirondack forests of northern New York. Ice damage produced widespread breakage of limbs and trunks in susceptible trees. Although ice storms are common within northeastern North American forests, the magnitude and extent of the 1998 storm far exceeded damage caused by typical ice storms in the recent past. While plot and stand-scale ecological impacts of ice storms have received attention insofar as tree species vulnerability, stand age susceptibility, and microhabitat alterations, larger-extent damage patterns have not been previously evaluated. The normalized difference vegetation index (NDVI) was employed to assess forest vigor and canopy density in atmospherically corrected Landsat Thematic Mapper (TM) satellite imagery of the Adirondacks. Digital change analysis of the baseline forest condition (1990 NDVI data), and the condition encountered in a post-storm image (1998 NDVI data) was conducted. Forest damage was separated from natural variations in canopy reflectance by employing a generalized linear model that incorporated in situ measurements. A robust empirical variogram analysis revealed that locations of tree damage were significantly correlated for distances up to 300 meters. Intensely-damaged forest exhibited greater spatial dependence, but over a smaller distance. Canopy damage was not greater proximate to stream and forest boundaries, and did not follow our hypothesis of decreasing damage with distance from the boundary. Overall, we show that local topography (elevation and aspect), forest composition (deciduous or coniferous), and the meteorological characteristics of the disturbance event acted together to determine the spatial extent of ice storm damage.This revised version was published online in May 2005 with corrections to the Cover Date.     

Characterizing indices of damage to tomato by the two- spotted spider mite,Tetranychus urticae Koch (Acari; Tetranychidae) to achieve biological control

Indices of damage caused by the two-spotted spider mite (Tetranychus urticae) on tomato are described to provide information for biological control using the predator mite Phyto- seiulus persimilis. Degrees of a scale of 1-5 for damage to leaflet and leaf, which when integrated to the plant can distinguish fifty classes of damage (0.0-5.0), are characterized by a number of mites and by a population structure. Scores of 3 for leaflet and leaf damage reveal 99-95% adult females and eggs, marking the end of the colonization phase. The further development of foliage damage to a score of 4 corresponds to the activity of new migrating forms (27-21%) emerging from the important egg sub-population. A plant with a damage degree of 2.0 and 2.5 has 14% and 50% respectively of its ten upper leaves presenting a damage degree of 3 and supporting 6,500 and 15,500 spider mites respectively. These scores seem to be the maximum tolerable levels. Leaves damaged at score 4 appear on plants classified at a mean leaf damage index of 2.8 and supporting 23,100 spider mites.     

不同栽培密度对生姜产量、品质的影响

为推动凯里市生姜产业发展,开展了生姜适宜栽培密度探讨研究。试验结果表明,生姜行距不宜低于50 cm,否则不利于培土,密度以调整株距为宜;生姜适宜的种植密度为8000株/667 m2,此密度下生姜产量高,产品品质优、商品性好;生姜不宜连作,连作病虫害严重,且随着栽培密度的增加而加重。     

光肩星天牛的生活习性及防治

光肩星天牛是园林树木的重要蛀干害虫,分布于国内二十多个省市,它不仅造成树势衰弱,枝条枯死,而且被害的枝干易被大风折断,严重者往往引起全株死亡。危害相当严重。是一种毁灭性蛀干害虫,树木从干基直到侧枝、顶枝都可受害,受害严重的树木千疮百孔将死亡或被砍伐。     

Establishment of intrauterine hypoxic-ischemic brain damage model in near term fetal rabbits

AIM: To establish intrauterine hypoxic-ischemic brain damage (HIBD) model in near term fetal rabbits at 29 d gestation age for the investigation of the pathogenesis and treatment of newborn HIBD. METHODS: Twenty-four pregnant New Zealand white rabbits at 29th gestational day were chosen for this project. Under combined general anesthesia and spinal anesthesia, a 4F Fogarty arterial embolectomy catheter was introduced into the left femoral artery. The blood supply of uterus in experiment group was blocked by inflating the catheter balloon with 0.3 mL saline for 20 min, 25 min, 28 min, 30 min and 40 min (n=4 for each experimental time group). The catheter balloon was not inflated in control group (n=4). All pregnant rabbits were subject to cesarean section 24 h after the experimental procedure to induce hypoxia-ischemia to the fetus. The general conditions of the newborn rabbits were recorded, and the neurobehavioral damage and histology of the brain tissue were assessed. RESULTS: During the entire procedure, the pregnant rabbits had stable vital signs, no hypoxia happened,and had a good tolerance to the anesthesia program. When the balloon was inflated, the pulses of right femoral artery disappeared and the right leg blood pressure became non-detectable in experimental groups. In contrast, no fluctuation of the right leg blood pressure in control group (P>0.05) was observed. Intrauterine hypoxia-ischemia caused neonatal and fetal rabbit death, neurobehavioral damage and brain cell death. When the balloon was inflated for 20 min, all fetal rabbits were alive and had no obvious neurologic damage. For 25~28 min, the stillbirth rates were 12.9% and 40.6%, respectively, while the live neonatal rabbits manifested neurobehavioral damage, edema neural cells, activated microglia cells and apoptotic brain cells. When blocking time beyond 30 min, above 80% fetal rabbits died. CONCLUSION: Continuous blockage of uterine blood supply in pregnant rabbits causes neonatal rabbit death, neurobehavioral damage and brain cell death. Different blocking time arouses different levels of brain damage. Continuous blockage of uterine blood supply for 25-28 min can establish fetal generalize hypoxic-ischemic brain damage rabbit model, which is a good animal model for the investigation of newborn HIBD.     

大理州“红阳”猕猴桃真菌性枝干的发生与病原鉴定

以大理州"红阳"猕猴桃枝干为试材,采用田间调查法调查病原菌对其危害状况,对采集的10份病样采用常规组织分离法分离病原,单孢纯化法获得病原菌,采用形态和分子法鉴定病原种类,以期明确大理州"红阳"猕猴桃枝干病害的发生状况及危害病原。结果表明:大理州"红阳"猕猴桃枝干病害发生严重,病株率高达69.6%,5个采样点共分离得到15个菌株,其中以链格孢菌(Alternaria alternata)、厚坦镰刀菌(Fusarium chlamydosporum)、小新壳梭孢菌(Neofusicoccum parvum)和间座壳属中一种(Diaporthe bohemiae)共4类病原菌出现频率最高,是优势种,分离率分别为55.6%、52.4%、49.8%和50.1%。利用柯赫氏法则对分离所得的所有菌株进行致病性测定,证实了优势菌株对猕猴桃茎杆的致病性,进一步明确了引起大理州猕猴桃茎杆的病原真菌。     

Changes in sucrose levels as an indicator of the marketable quality of cauliflowers exposed to freezing temperatures

It is suggested that sucrose determinations may act as a reliable indicator of the extent of hidden frost damage and subsequent deterioration of the field crop before and during marketing, where reliable visual estimates cannot be made. Determinations of soluble sugars were carried out on curd tissue before and after subjection to low temperature. Sucrose always increased significantly, but reducing sugars showed no significant change. Natural and artificial freezing both caused similar changes in sucrose levels. A connection between sucrose content and frost hardiness was not established, although sucrose increase accompanies hardening of the tissues.     

Biology and control of the apple canker fungus Neonectria ditissima (syn. N. galligena) from a Northwestern European perspective

A review of apple canker caused by Neonectria ditissima is presented for Northwestern Europe with a focus on the Lower Elbe region (Northern Germany). Whereas conidia released by rainsplash are produced mainly from spring to autumn, the liberation of wind-borne ascospores peaks in autumn and/or early spring. Infection occurs via natural as well as pruning-induced wounds, some of which are present throughout the year. Autumnal leaf scars are the most frequent entry point for N. ditissima. Wounds on tree trunks, especially bark cracks in the crotch regions, are potentially even more serious because cankers on trunks and leader shoots commonly cause the total loss of a tree. Surface moisture is a prerequisite for leaf scar infections but possibly not for an entry through other wounds. Irrespective of the entry route, successful infection of a wound requires a mass inoculum of at least 50–100 conidia or ascospores. Infections of trees originating in nurseries may enter a state of latency from which they can break out up to 3 years after the trees have been explanted into the production orchard. Streaks of brown wood discolourations can be caused both by systemic colonisation of the xylem by N. ditissima and by winter frost damage. Apple varieties may show pronounced differences in their sensitivity to canker. For highly susceptible varieties, this disease can be a major production-limiting factor. Flower infections by N. ditissima commonly lead to a pre-harvest rot at the blossom end of the fruit, whereas infections of the growing fruit before harvest lead to a storage rot. Rigorous pruning is an essential canker control measure. Chemical control during the growing season is achieved by apple scab fungicides such as dithianone, captan or dodine. At leaf fall and in winter, copper fungicides are indispensible for controlling canker on highly susceptible varieties in Northern Germany.     

套袋苹果内新害螨——乱跗线螨

苹果黑点病(黑点症)主要发生在套袋苹果上,发生率高达90%。为进一步确定套袋苹果黑点症的危害因子,2003-2005年进行了调查、模拟昆虫危害、室内培养、药剂试验等研究。结果表明,调查套袋苹果上和果袋内的害虫数量总计为2079头,其中乱跗线螨占91.8%;乱跗线螨的发生与“黑点症”症状的出现密切相关,而康氏粉蚧和甲螨没有此相关性;刺孔试验出现了与苹果“黑点症”相同的危害状;在使用化学杀螨剂的化防果园苹果“黑点症”的发生率仅为12%;“黑点症”病斑处的黑点并不随着果实的生长而扩展,在室内高湿培养下亦不扩展,这一点不同于其他病害的发展规律。综上所述,乱跗线螨(Tarsonemus confusus Ewing)是套袋苹果“黑点症”的危害因子之一。     

Examining strain propagation in the branch unions of Quercus alba L. and Quercus montana Willd.

Branch failure resulting from static loading events can be caused by ice, snow, or a climbing arborist aloft in a tree and can cause power outages, road blockages, costly property damage, or personal injury. In previous studies, researchers calculated bending stress to investigate the load-bearing capacity of branches. Yet, these calculations require geometric measurement of the wood that may not always be readily measure post failure. As stress and strain are linearly related, this study used static loading trials and digital image correlation to measure strain, tissue displacement, to gain insight on how loads move through the branch union zone. The results indicate that strain is located distally in the branches and diminishes through the branch union zone, suggesting that branch unions may serve a role in the damping of loads in trees.     

The adaptive response of low dose sodium nitrite pretreatment on cultured CHL cells to DNA damage caused by high dose sodium nitrite

AIM: To study if low dose NaNO₂ can induce the adaptive response of cultured Chinese hamster lung cells（CHL cells）to DNA damage. METHODS: Single cell gel electrophoresis technique was used to detect the DNA damage in CHL cells exposed to NaNO₂ at different concentrations. CHL cells were pretreated with NaNO₂ of concentrations of 0.01 mg/L, 0.1 mg/L and 1 mg/L respectively. And the adaptive response to the toxicity of 1g/L NaNO₂ was observed. The activity of polyADP- ribose polymerase (PARP-1) of CHL cells was inhibited with 3-aminobenzamide(3AB) before or after pretreated with low dose of NaNO₂. And the changes of the adaptive response were observed. RESULTS: The rate of tailing cells was 7.87% when the cells were exposed to 1 g/L NaNO₂ without pretreatment with low dose NaNO₂. An extremely remarkable statistics significance (P＜0.01) was observed when compared the difference to control group. NaNO₂ of 0.01 mg/L and 0.1 mg/L could induce the adaptive response of cultured CHL cells to DNA damage caused by 1 g/L NaNO₂. The rate of tailing cells was 3.55% and 1.06％ respectively, which was much lower than that of no-pretreatment group(P＜0.05；P＜0.01). But the rate of tailing cells was 6.09% when the cells were exposed to 1 g/L NaNO₂ with pretreatment of 1 mg /L NaNO₂, which had no significant difference compared with the rate of tailing cells in control group (P＞0.05). The adaptive response could be blocked when the activity of PARP-1 was inhibited with 3AB before the low dose pretreatment, but could not be blocked when the activity of PARP-1 was inhibited after low dose NaNO₂ pretreatment 6 h. CONCLUSION: NaNO₂ of concentration that equals to or lowers than 0.1 mg/L can induce the adaptive response of cultured CHL cells to DNA damage caused by high dose NaNO₂ through PARP-1 activation. And the dose of NaNO2 that can induce adaptive response might not cause the DNA damage.     

Relation of peel damage in citrus fruit to wind climate in orchard and its control

Peel damage originated by wind is the main abiotic cause of citrus fruit discards for export in Uruguay. Natural windbreaks such as Eucalyptus and Casuarinas have not been effective in reducing it. This research was carried out during three years in a citrus orchard situated in the coastal plain of Uruguay (35° SL). The purpose of this work was to study wind climate inside the orchard, fruit seasonal sensitivity, basal leaf effect on the onset and evolution of peel damage, and the efficiency of artificial windbreaks to reduce fruit discard of ‘Ellendale’ tangor. Average wind velocity in the orchard did not exceed 5 m s⁻¹. First peel scars were evident two weeks after petal fall and damaged fruit percentage importantly increased during the first stage of fruit growth. Low energy vortexes caused almost permanent friction between basal leaves and the developing fruitlets growing in their axil. Removal of the basal leaf decreased significantly wind damaged fruit. Natural wind flow modification through the use of semi-porous artificial windbreak nets (5 cm by 10 cm mesh) modified low energy vortexes and increased significantly the percentage of export quality fruit. We conclude that this type of net is more efficient than natural windbreaks or classical nets to reduce wind damage in citrus fruit.