Oral Lesions Associated with Orotracheal Administered Mechanical Ventilation in Critically III Dogs

The incidence and clinical progression of oral lesions in a cohort of critically ill patients administered mechanical ventilation via orotracheal intubation were observed prospectively in the Intensive Care Unit (ICU) of the University of California, Davis Veterinary Medical Teaching Hospital. Oral cavities of these patients were examined within 24 hours of being placed on the ventilator and at least daily thereafter during ventilator therapy. As part of the study protocol, any lesion noted was treated. Twenty-one critically ill canine patients (median age of 7 yrs; range <1 to 19 yrs) were observed from 1 January 1995 through 31 August 1995. Over ninety percent (90.5%) of the observed patients developed oral lesions subsequent to being mechanically ventilated. Erosive and ulcerative mucosal lesions were the most frequently observed (15/43) with the tongue being the most frequently involved oral structure. Most of the observed soft tissue oral lesions appeared secondary to persistently applied pressure from teeth, mouth gags, endotracheal tubes, and other monitoring devices. Efforts taken to prevent persistently applied trauma, such as periodic positional changes of equipment and padding of susceptible structures, apeared effective in preventing oral lesions. There were indications of gastric reflux in 6 patients (28.6%), as evidenced by secretions in the oral cavity with a pH of <6 and containing digested blood. Ulcerative lesions in the subset of patients with gastric reflux seemed to worsen in severity with exposure to the low pH secretions. Over the course of the study, the ICU nursing staff developed an effective protocol for the care of the oral cavity: treating mucosal erosions and ulcers topically8 with a dilute chlorhexidine solution (0.05%), removing oral secretions via suction as needed, and padding persistently traumatized tissues with glycerin moistened gauze. Oral lesions in orotrachealy intubated and mechanically ventilated patients are predictable, preventable, and treatable. Most lesions are pressure induced, associated with monitoring/therapeutic equipment, and appear to be preventable with appropriate nursing protocls. Most observed oral lesions clinically improved with routine, periodic dilute chlorhexidine rinses and relief of applied pressure.     

转基因植物的生物安全性

植物遗传改良的主要目的之一就是通过提高植物抵抗病虫害的能力,来增加作物的产量。然而,即使是转基因植物获得了成功,依然要对其生物安全性进行评估,以确保有意识的生物学修饰被介入,来平息公众的恐惧。甚至在植物中只有一个或两个基因可能被修改,都不能假定认为它们的蛋白质结构不会被改变。任何改变都可能导致不必要的植物代谢产物的产生,包括潜在的有毒化合物。     

Genetic analysis of flowering and maturity time in high latitude spring wheat

Due to the short growing season in the high northern latitudes, the development of early maturing spring wheat (Triticum aestivum L.) cultivars is important to avoid frost damage which can lower production and quality. We investigated earliness of flowering and maturity, and some associated agronomic traits, using a set of randomly selected high northern latitude adapted spring wheat cultivars (differing in maturity) and their F₁ and F₂ crosses made in a one-way diallel mating design. The parents, and their F₁ and F₂ crosses were evaluated under field conditions over 2 years. Anthesis and maturity times were controlled by both vernalization response and earliness per se genes, mainly acting additively. Non-additive genetic effects were more important in controlling grain fill duration, grain yield and plant height. Additive × additive epistatic effects were detected for all traits studied except time to anthesis. Segregation analyses of the F₂ populations for time to anthesis indicated the presence of different vernalization response genes. Molecular genetic analyses revealed the presence of Vrn-A1 and Vrn-B1 genes in the parental cultivars. Narrow-sense heritability was medium to high (60–86%) for anthesis and maturity times but low to medium (13–55%) for grain fill duration, plant height and grain yield. Selection for early flowering/maturity in early segregating generations would be expected to result in genetic improvement towards earliness in high latitude spring wheats. Incorporation of the vernalization responsive gene Vrn-B1 in combination with vernalization non-responsive gene Vrn-A1 into spring wheats would aid in the development of early maturing cultivars with high grain yield potential for the high latitude wheat growing regions of the northern hemisphere.     

Emission Inventories for SO2 and NOx in Developing Country Regions in 1995 with Projected Emissions for 2025 According to Two Scenarios

Water, Air, &; Soil Pollution - Top-down inventories of anthropogenic SO2 and NOx emissions were compiled for 1995 for developing country regions. Regional emission factors were used to generate...     

Evaluating estimators of the numbers of females with cubs-of-the-year in the yellowstone grizzly bear population

Current management of the grizzly bear (Ursus arctos) population in Yellowstone National Park and surrounding areas requires annual estimation of the number of adult female bears with cubs-of-the-year. We examined the performance of nine estimators of population size via simulation. Data were simulated using two methods for different combinations of population size, sample size, and coefficient of variation of individual sighting probabilities. We show that the coefficient of variation does not, by itself, adequately describe the effects of capture heterogeneity, because two different distributions of capture probabilities can have the same coefficient of variation. All estimators produced biased estimates of population size with bias decreasing as effort in creased. Based on the simulation results we recommend the Chao estimator for model M _h be used to estimate the number of the female bears with cubs of the year; however, the estimator of Chao and Shen may also be useful depending on the goals of the research.     

Nutritional disturbances and histological changes in declining forests

“New type” forest damages have been observed in West Germany since the mid-1970's and discussed in North America since the early 1980's. Various types of damage are associated with typical foliar discoloration symptoms related to site characteristic nutritional disturbances. The macronutrients are generally Mg, Ca, and K. Based on foliar and soil analysis results diagnostic fertilization trials were established at a wide variety of sites and stands in West Germany as well as in North America. The appropriate application of fast soluble fertilizers proved that damage symptoms associated with nutritional disturbances can frequently be mitigated within a relatively short period. The observed visual revitalization corresponds well with foliar analysis data obtained continuously for the last 5 yr. Soil analyses also reflect the improved nutrient supply. Investigations of older fertilizer trials indicated that stands fertilized before the appearance of “new type” damage symptoms are considerably more vital when compared to the untreated control plots. Remarkable results were derived from histological research. Microscopic analysis of needles proved the regeneration potential on a histological level for moderately yellowed needles after fertilization. Furthermore, needles of nutrient deficient trees reveal typical differences of tissue damages when compared to SO₂ fumigated or O₃ impacted needles. Thus, histological investigations can be used as a diagnostic tool to differentiate between direct and indirect forest damages.