Effect of fruit maturity,seed weight and storage time on the viability and germination of the seed of candelilla (<i>Euphorbia antisiphylitica</i> Zucc.)

Candelilla (Euphorbia antisiphylitica Zucc.) is a very important plant resource in the arid lands of Northern Mexico. This is because the wax content coating the stem has unique properties which have been useful for multiple applications in the food industry, electronics, cosmetics, etc. However, the intensive exploitation of this resource has caused a great decrease in the populations of this species making necessary to consider strategies for their conservation and sustainable use. One of the primary needs with regeneration purposes is to know their reproductive processes, particularly the biotic and/or abiotic factors that determine the viability and germination of seeds. The present study evaluated the (1) germination and seed viability in relation to the ripeness degree of the fruit at the time of collection, (2) weight of the seed (low, medium and high), and (3) storage time (1, 3, and 5 months). Fruits from four locations, two in the State of Coahuila (Las Coloradas and Candela) and two in the State of Nuevo Leon (Icamole 1 and Icamole 2), were collected. Three germination assays were carried out corresponding to each month of storage. Seed viability was determined by the tetrazolium test. The average weight of the candelilla seeds was 0.0029 ± 0.0010 g, with extreme average values of 0.0018 ± 0.0006 g at Las Coloradas and 0.0036 ± 0.0010 g in Icamole 2. Those seeds with heavier weight obtained from red fruits and with 1 month of storage showed the highest average percentage of viability (66.87 ± 24.19%). At the same time, seeds with around average weight, obtained from red fruits and five months of storage, showed the highest average germination percentage (50.00 ± 9.42%).     

Myocutaneous flap ischemia: flow dynamics following venous and arterial obstruction.

To further clarify the pathogenesis of the poorer prognosis in skin flaps exposed to venous stasis compared with arterial insufficiency, a microsphere study was conducted in bilateral rectus abdominis island flaps in seven pigs. The relationship between capillary blood flow and arteriovenous (A-V) shunting was studied during progressive 1-hour intervals of arterial insufficiency and venous stasis and during 3 hours of reperfusion. Under controlled conditions, total blood flow was reduced from 100 percent to both 50 and 25 percent by application of an adjustable clamp on the artery supplying one flap and on the vein draining the contralateral flap. The relative distribution between A-V shunt flow and capillary blood flow was different in arterial insufficiency when compared with venous stasis at both the 50 percent and the 25 percent blood flow levels. In the arterial insufficiency flaps, the A-V shunt flow and capillary blood flow shared the total blood flow in the following percentages: 64/36 (at 100 percent total blood flow), 44/56 (at 50 percent total blood flow level), and 22/78 (at 25 percent total blood flow level). In the venous stasis flaps, the A-V shunt flow and the capillary blood flow shared the total blood flow in percentages of 70/30, 66/34, and 55/45, respectively. Hence, in arterial insufficiency flaps, capillary blood flow was spared by a relatively greater decline in A-V shunting compared with venous stasis flaps. Redistribution of capillary blood flow from subcutaneous tissue to muscle was observed, whereas blood flow was equally distributed throughout the length of the flaps at all flow levels.(ABSTRACT TRUNCATED AT 250 WORDS)     

Glycogenosis Type III in the Dog

Enzyme and glycogen structure studies have been carried out on tissues of a glycogenotic dog, the clinical and pathological characteristics of which are reported in the accompanying paper. Liver glucose-6-phosphatase, leukocyte and liver acid maltase, and liver and skeletal muscle glycogen Phosphorylase all appeared largely unaffected. The activity of the muscle and liver debranching enzyme (amylo-l,6-glucosidase), determined by two independent assay methods, was, however, reduced to between 0 and 7 % of normal activity. Glycogen structure studies with Phosphorylase or iodine spectra revealed that the abnormally large amounts of glycogen found in liver and skeletal muscle had abnormally short branches, as would be expected for a deficiency of debranching enzyme. It is thus clear that the dog had suffered from the equivalent of Cori's disease (limit dextrinosis, type III glycogen storage disease). Preliminary data indicate that it may be possible to identify heterozygotes based on a study of the debranching enzyme of leukocytes.     

Application of stains in clinical microbiology

Stains have been used for diagnosing infectious diseases since the late 1800s. The Gram stain remains the most commonly used stain because it detects and differentiates a wide range of pathogens. The next most commonly used diagnostic technique is acid-fast staining that is used primarily to detect Mycobacterium tuberculosis and other severe infections. Many infectious agents grow slowly on culture media or may not grow at all; stains may be the only method to detect these organisms in clinical specimens. In the hands of experienced clinical microscopists, stains provide rapid and cost-effective information for preliminary diagnosis of infectious diseases. A review of the most common staining methods used in the clinical microbiology laboratory is presented here.     

Persistence during Tasks with Horses in Relation to Social Support,General Self-efficacy and Self-esteem in Adolescents

ABSTRACT

In young people, interactions with horses may contribute to the development of social skills and self-efficacy. Our aim was to identify relationships between psychological variables and young people's experience of activities with horses. Participants in this study were 13–15-year-old adolescents (n = 25), given a 4-month intervention consisting of weekly sessions of stable work and horseback riding. We investigated the relationship between psychological variables from survey data with video-recorded behavioral observations during tasks and contact with horses. From the behavioral data, we calculated the frequency per hour of “trying again” when met with a challenge, as a measure of participants' persistence in horse-related tasks. The number of times per hour that that participant initiated contact with the horse was used as a measure of frequency of physical contact (petting). We examined correlations between the change from early to late stages of the intervention in trying again during horse-related tasks and for physical contact and three psychological variables measured prior to the intervention: perceived social support, self-esteem, and general self-efficacy. We detected an association between lower pretest levels of perceived social support and general self- efficacy, and an increase during the intervention in persistence of trying again when met with challenges during tasks with the horse. In a linear regression analysis, controlling for initial levels of persistence during horse-related tasks, self-esteem, and self-efficacy, social support was the only unique predictor of an increase in persistence during the intervention. No association was found between the psychological variables and change in frequency of petting the horse. The results indicate that adolescents with lower levels of perceived social support at the start of the intervention showed greater increases in their persistence in trying again after being met with challenges during horse-related tasks. Since persistence is a central aspect in the development of mastery of tasks, the possible positive social impact of the horse/stable environment should be given more attention in future intervention research.