Postnatal autonomic activity in the preterm lamb

Background

Early postnatal abnormalities of autonomic nervous system (ANS) activity, including at baseline and following cardiorespiratory challenge, are involved in apneas-bradycardias of prematurity, apparent life-threatening events of infancy and sudden infant death syndrome. Literature data suggest that baseline ANS activity does not mature normally after premature birth.

Objectives

This study performed in preterm lambs was aimed at assessing ANS maturation at baseline and following laryngeal chemoreflexes (LCR), a group of reflexes triggered by the contact of liquids with the laryngeal mucosa.

Methods

Heart rate variability (HRV) and baroreflex sensitivity (BRs) were measured at baseline and after LCR during polysomnographic recordings performed in five non-sedated lambs born 15 days prematurely. Laryngeal chemoreflexes were induced by distilled water or acid (pH 2) during sleep and wakefulness on postnatal days 7 (D7) and 14 (D14, full-term equivalence).

Results

While the life-threatening cardiorespiratory events of the LCR observed at D7 were no longer present at D14, baseline and post-LCR HRV and BRs indices were significantly lower at D14 compared to D7 (up to p < 0.001). These results suggest that an initial autonomic overactivity was present at D7 and normalized at D14.

Conclusion

The autonomic cardiac and baroreflex control appears to follow a specific evolution in the preterm compared to the full-term newborn lamb, with an important initial autonomic stress, which normalizes at an age equivalent to full-term. Potential relevance of these findings in relation to anomalies of cardiac control in the early postnatal period, such as apneas-bradycardias of prematurity, apparent life-threatening events of infancy and sudden infant death syndrome, awaits further studies.     

两种方法测定羊外周血淋巴细胞增殖的研究

本试验比较~3H胸腺嘧啶核苷(~3H-TdR)渗入法和BrdU-ELISA方法测定羊外周血淋巴细胞增殖。分离健康羊外周血淋巴细胞,与不同浓度的非特异刺激因子刀豆素A(concanavalinA,1.0,0.5,0.25,0.125,0.0625,0.0313,0.0156,0.0078,0.0039μg/孔)培养,分别用~3H胸腺嘧啶核苷(~3H-TdR)和5-溴-2’-脱氧尿苷(BrdU)标记细胞,测定刺激细胞和对照细胞的每分钟脉冲数cpm或光吸收值OD,计算刺激指数SI和光吸收值差△OD,统计学方法分析SI和△OD的相关程度。同样的方法测定羊试验感染肝片吸虫(Fasciola hepatica)后,在感染早期阶段(PIWO-PIW4)其外周血淋巴细胞在特异性抗原-片形吸虫分泌排泄产物(ESP,5μg/孔)刺激下的增殖。结果表明,刺激指数SI和光吸收值差△OD在两个试验中的相关系数分别为0.946和0.924,SI和OD用均呈强正线性相关。BrdU-ELISA方法无同位素放射物,且敏感、快速、方便,和~3H-TdR渗入法一样可以用于测定淋巴细胞增殖。     

p-Hydroxyphenylpyruvate dioxygenase inhibitor-resistant plants

The enzyme p-hydroxyphenylpyruvate dioxygenase (HPPD) catalyzes the formation of homogentisic acid, the aromatic precursor of plastoquinone and vitamin E. HPPD is the specific target of several herbicide families: isoxazoles, triketones and pyroxazoles. Its inhibition results in the depletion of the plant plastoquinone and vitamin E pools, leading to bleaching symptoms. These herbicides are very potent for the selective pre- and in some cases post-emergence control of a wide range of broadleaf and grass weeds in maize and rice. Their herbicidal potential raised interest in the development of highly resistant transgenic crops. This goal was first achieved by over-expression of a bacterial HPPD in crop plants, and an increased level of resistance was obtained by using a mutant enzyme. A second strategy based on bypassing HPPD in the production of homogentisate was then developed. Recently, a third strategy of resistance based on the increase of p-hydroxyphenylpyruvate substrate flux has been developed. This was achieved by the introduction of the yeast prephenate dehydrogenase gene (PDH) into transgenic plants already overexpressing HPPD. In addition to a high level of herbicide resistance, a massive accumulation of vitamin E, mainly tocotrienols, was observed in leaves of the transgenic HPPD-PDH plants.     

Description and first results of a BVDV control scheme in Brittany (western France)

A collective zoo-sanitary control scheme for BVDV has been implemented in Brittany in successive steps since 1998. Prior evaluation of prevalence and dynamics of infection through bulk-milk ELISA showed that 40% of the dairy herds were likely to be free of BVDV but that, in the long term, no improvement was to be expected without control of new infections. The next step was a test-and-cull programme for PI animals in ELISA positive herds. Ten percentage of the herds were found to have at least one PI animal. The incidence decreased during this step. To lower costs of testing traded animals, a database was developed to collect all the available information to trace animals already known to be non-PI.     

Multiple eyelid apocrine hidrocystomas in two Persian cats

Abstract Two middle-aged Persian cats were presented for evaluation of periocular masses. On examination, multiple pigmented nodules, 2-10 mm in diameter, were found in the periocular skin. Excisional biopsy revealed unilocular cystic lesions derived from apocrine sweat glands and resembling apocrine hidrocystomas of the eyelids described in humans. Immunostaining for Ki67 identified actively proliferating epithelial cells and demonstrated, for the first time, that these cystic lesions are adenomatous proliferative tumors (cystadenomas) rather than retention cysts. In both cases, additional lesions appeared within 6 to 9 months at affected and previously unaffected sites on the eyelids.     

Concorde sonic booms as an atmospheric probe

Infrasound generated by the sonic boom from the inbound Concorde supersonic transport is recorded at Palisades, New York (Lamont-Doherty Geological Observatory), as a series of impulses from distances varying from 165 to about 1000 kilometers. Refraction effects determined by temperature and wind conditions return the signal to the surface from both stratospheric (40 to 50 kilometers) and thermospheric (100 to 130 kilometers) levels. The frequency of the recorded signal is a function of the level of reflection; the frequency decreases from impulse stretching as the atmosphere becomes more rarified relative to the sound pressure. The horizontal trace velocity of the signal across the array of instruments is equal to the acoustic velocity at the reflection level. The sonic boom can thus be used to provide temperature-wind parameters at reflection levels estimated from the signal frequency. Daily observed signal variations have indicated significant variations in these parameters.     

一种连续测定葡萄果实糖分积累的新方法

介绍了一种测定葡萄二次生长高峰期葡萄果实糖分卸载和积累的非离体试验体系-新浆果杯法。新浆果杯是由1粒剥皮后的葡萄果实侵入盛有缓冲溶液、由注射器制成的小杯组成。利用该试验体系,水分胁迫和2．5 mmol/L对氯汞苯甲酸(pCMB)可明显抑制葡萄果实糖分卸载,而1．5 mmol／L二硫基苏糖醇(DTT)则可促进葡萄果实糖分卸载。结果表明新浆果杯法可连续测定葡萄第二生长期果实糖分积累,是研究葡萄韧皮部糖分卸载机理和内外因子对葡萄果实糖分积累影响的理想方法。     

Modeling recent bark stripping by red deer (Cervus elaphus) in South Belgium coniferous stands

? Context

Over the past few decades, the impact of large herbivorous ungulates on forest vegetation has been clearly highlighted. Among those impacts, bark stripping of coniferous trees is one of the most damaging. Bark stripping leads to rot development, inducing serious loss of timber value.

? Aims

The present study aimed firstly at evidencing the factors explaining the variations observed in fresh bark peeling rate for spruce and Douglas-fir in southern Belgium and secondly at identifying the key factors to consider when setting up a deer management plan.

? Method

Fresh bark peeling rate was recorded with a systematic sampling survey from 2004 to 2007. The covered territory was then divided into 63 distinct hunting zones of area ranging from 1,000 to 25,000 ha. About 5,000 plots were monitored annually. Each zone was characterized with a large number of explanatory variables. The explanatory variables were integrated firstly into fixed linear models using a stepwise procedure, and then into a mixed model.

? Results

The significant variables included in the model (R ²?=?44 %) are (by decreasing order of importance) red deer densities, proportion of coniferous stands and agricultural areas, snow cover, distance to urban habitats, and species diversity in the understory.

? Conclusion

The models revealed the impacts of several factors on bark peeling: deer density, deer-carrying capacity of the territory, landscape structure, and severity of winter conditions. The adjusted model allowed subtracting the impact of winter conditions in order to produce a relevant indicator for hunting management. In addition, the model was used to assess the sensitivity of a forested area to bark peeling based on its environmental characteristics.     

Glacial-interglacial changes in moisture sources for greenland: influences on the ice core record of climate

Large, abrupt shifts in the (l8)O/(16)O ratio found in Greenland ice must reflect real features of the climate system variability. These isotopic shifts can be viewed as a result of air temperature fluctuations, but determination of the cause of the changes-the most crucial issue for future climate concerns-requires a detailed understanding of the controls on isotopes in precipitation. Results from general circulation model experiments suggest that the sources of Greenland precipitation varied with different climate states, allowing dynamic atmospheric mechanisms for influencing the ice core isotope shifts.     

Effects of silage preservation on astaxanthin forms and fatty acid profiles of processed shrimp (Pandalus borealis) waste

Acid silage of shellfish processing waste has been reported to be a good and economical technique to protect these biomasses from bacterial decomposition. Shrimp (Pandalus borealis) by-products contain some value-added nutrients for the aquaculture industry such as carotenoid pigments (mainly astaxanthin) and n − 3 polyunsaturated fatty acids. The aim of this work was to determine the effect of ensiling shrimp waste during a long period of time (more than 3 months) on some unstable components such as the astaxanthin forms (free, mono- and diesterified) and polyunsaturated fatty acids. Comparisons of astaxanthin forms and the fatty acid profiles were performed on defrosted shrimp waste and on a 14-week-old shrimp waste silage. No significant difference (P ≥ 0.05) in the total lipids extracted from the two forms of shrimp waste was observed. Nevertheless, a small quantity of the red pigment, presumably an astaxanthin portion, was observed to stay firmly bound to the shrimp carapace after the solvent extraction in shrimp waste compared to the full recovery obtained in ensiled shrimp waste. This may explain the significantly (P < 0.05) higher concentration of total astaxanthin (4.57 vs 3.99 mg/g) found in the crude oil extracted from shrimp waste silage. Higher percentages (P < 0.01) of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were found in esterified astaxanthin from shrimp waste silage (43.9% and 45.5%) in comparison with their shrimp waste (24.7% and 20.3%) counterparts. This suggests that EPA and DHA are the principal fatty acids esterified with the portion of astaxanthin linked to chitin in the shrimp carapace. The utilization of shrimp waste silage as a pigmenting component of salmonid feeds is also discussed.