Cardiovascular risk among ultra-endurance runners

BACKGROUND

Our objective was to determine the prevalence and clinical correlates of conventional cardiovascular risk factors among ultra-endurance marathon runners.

METHODS

An electronic internet survey to characterize modifiable cardiovascular risk factors including diabetes, hypertension, dyslipidemia, tobacco exposure and obesity (BMI >30) among competitive ultra-endurance runners.

RESULTS

Among 290 respondents (mean ± SD, 42 ± 11 years, 31.4% female), 106 (36.6%) had at least one established cardiovascular risk factor. Female sex, younger age and participation in competitive high school or collegiate sports were associated with freedom from cardiovascular risk factors. There were no significant associations between risk factor status and either hours per week of running training (risk factor negative = 10 ±7 vs. risk factor positive = 11 ± 8 hours, p=0.42) or years of ultra-endurance competition (6 ± 8 vs. 7 ± 9 years, p=0.38). Runners with at least one cardiovascular risk factor were more likely to have had personal or peer concerns about excessive alcohol use.

CONCLUSIONS

Conventional cardiovascular risk factors are common among ultra-endurance runners. Early life participation in competitive sports, rather than adult exercise habits, is associated with freedom from the development of cardiovascular risk factors during middle age. Determining mechanistic explanations for the legacy effect of early life exercise as a means to reduce cardiovascular risk among aging athletes represents an important area of future work.

Optimising ripening temperatures of Cavendish bananas var. 'Williams' harvested throughout the year in Queensland, Australia

Varying banana ripening temperatures were examined throughout the year to ensure optimum quality and shelf life of commercially ripened fruit in Australia. Cavendish bananas (var. 'Williams') were harvested throughout the year 2000 and were ripened at 14, 16, 18 and 20°C with 300 μL/L ethylene on 2 consecutive days until fruit were more yellow than green and then subsequently stored at 22°C until the end of the experiment. Ripening bananas at 14 and 16°C extended shelf life by up to 50 and 32%, respectively. However, ripening bananas at 14 and 16°C did increase peel discolouration, especially on bananas chilled in the field in winter. Bananas ripened at 18 or 20°C throughout the year had an average shelf life of 6 days and consistently lower peel discolouration. Therefore, ripening at 18 or 20°C throughout the year results in a better visual appearance of the fruit, which is essential for consumers.

Detection of Prunus necrotic ringspot virus in almond: effect of sampling time on the efficiency of serological and biological indexing methodologies

The reliability of enzyme-linked immunosorbent assay (ELISA) and indexing methodologies for the detection of Prunus necrotic ringspot virus (PNRSV) in almond was assessed under local conditions. Thirteen field-grown almond trees were sampled fortnightly throughout the growing season. Petal and leaf homogenates were used for ELISA and to inoculate herbaceous indicator species, while buds collected from October onwards were budded to woody indicators. ELISA reliably detected PNRSV in petals and young leaves from bud-break until the cessation of stem elongation. While herbaceous indexing was not as reliable as ELISA, woody indicators could differentiate positive from negative samples reliably throughout the testing period. However, for mass screening of foundation plantings, nursery stock and elite germplasm, woody indexing is too costly and slow to give results. The use of ELISA can overcome these limitations but the timing of sample collection is critical. Petal or leaf tissue collected early in the season will yield the most reliable results.

Application of DNA fingerprinting for the classification of selected almond [Prunus dulcis (Miller) D. A. Webb] cultivars

Almond cultivars developed in Australia are thought to have descended from 2 breeding lines, 1 from hard-shelled Spanish/Jordan types, and the other from paper-shell Californian types. However, the precise derivation of many individual Australian cultivars is uncertain. Randomly amplified polymorphic DNA (RAPD) was used to estimate the genetic similarities between 50 accessions of almond cultivars derived from Australia, California, Europe and the Middle East, and individual accessions of Prunus orientalis (Miller) D. A. Webb and Prunus webbii (Spach) Vieh. Amplification products were analysed using the simple matching coefficient and the unweighted pair group method with arithmetic averages to cluster individuals into a dendrogram. Cultivars known to have originated in Europe or the Middle East clustered in a different group from those known to have originated in California confirming the 2 suspected breeding lines. The origin of some common Australian commercial cultivars was inferred by their placement on the dendrogram, and the possible parentage of some Australian selections is discussed.

Xylem development in relation to water uptake by roots of grapevine (Vitis vinifera L.)

Axial resistance (R_a ) was estimated from xylem diameter measurements obtained from periodic acid and toluidinc blue O (PAS-TBO) stained sections of Vitis vinifera L. ev. Shiraz. Multiple linear regression showed a strong negative relationship between axial resistance and either root diameter or distance from the root tip. Water stress treatments did not affect the relationships, but plant age significantly influenced the intercept of the regression. The use of both lignin and cytoplasm stain showed that some vessels retained degenerating protoplasm which would impede water flow. Inclusion of these vessels in calculations of axial resistance could account for the underestimation reported by some authors in comparison with experimental determinations. Calculations based on the assumption that all xylem vessels, large and small, are involved in axial water conduction showed that use of mean xylem diameter might result in overestimating values by a magnitude of between 1.7 and 4.4. The use of individual xylem vessel diameters gave more accurate estimation of axial resistance. Some adjacent secondary xylem and metaxylem vessels were observed to merge into single vessels as a result of breakdown of the wall between them. Implications of such a developmental phenomenon are discussed.

Variability in cut flower production of Banksia coccinea R.Br. and Banksia menziesii R.Br. at six locations in southern Australia

Cut flower production from seedling plants of Banksia coccinea and B. menziesii was investigated on 6 commercial plantations in southern Australia (3 in each of South Australia and Western Australia). Both species exhibited variability in the total number of blooms produced per plant, bloom quality, stem and inflorescence length of the harvested bloom, and the time of production within the flowering season. Production of B. coccinea in South Australia extended from July to October, with most blooms harvested in September. Blooms on B. menziesii were produced over an 8-month period from March to October, with peak production in March-April. Each species showed some abnormal floret development. There were significant (P<0.001) between-site differences in B. coccinea for the number of blooms produced and the proportion which were abnormal. Maximum production (average 75.3 blooms per bush) was recorded near Albany, Western Australia, close to the natural habitat of B. coccinea. In comparison, few blooms (average 3.2 per bush) were produced at Muchea, Western Australia.

Insect pollination of mango in northern Australia

Large native insect species were shown to pollinate mango (Mangifera indica L.) in northern Australia. The pollinators, in decreasing order of efficiency, were wasps, bees, large ants and large flies. It was found that the most efficient pollinators were those that carried large numbers of pollen grains on their thoraces and used a short proboscis or short mouth parts to feed on nectar. Large Diptera and the native bee, Trigona sp., frequently moved from tree to tree and thus were probably the most effective cross pollinators. Of randomly selected hermaphrodite mango flowers, 36% were pollinated.

Ultrastructure and histochemistry of the watermelon stigma

The ultrastructure and histochemistry of the watermelon stigma were followed from 6 days before flower opening to anthesis. Starch and lipid were present in the immature papilla cells but had largely disappeared from the cells by anthesis, when carbohydrate and lipid were present in the stigma secretion external to the cell wall. Th mature papilla cells had simple wall thickenings and were transfer cells. The wall thickenings were associated with dictyosomes and secretory vesicles. Other characteristics indicating a secretory function for the papilla cells included plastid-ER complexes and close associations between ER and secretory vesicles at the plasmalemma. Granulocrine secretion involving dictyosomes and ER is suggested for the carbohydrate component of the secretion.

Structural changes in the pollinated and unpollinated avocado stigma and style

Structural changes in the pollinated and unpollinated avocado (Persea americana Mill) stigma and style up to 42 h after first opening of the flower were investigated using light and electron microscopy. The pollen tubes grew in the stigma secretion and intercellular substance and initial contact occurred between the plasma membrane of the male and the cuticle and stigma secretion of the female. The pollen tube wall started to develop 15 min after pollination and increased in thickness up to 24 h after pollination. By 18 h after first opening of the flower, starch had disappeared and cell wall thickenings were present in both the pollinated and unpollinated stigma and style. The wall thickenings developed more slowly in the unpollinated than in the pollinated tissue. They contained lipid and were bounded by callose. Degeneration of the cytoplasm of some of the papilla and transmitting tissue cells occurred only following the passage of the pollen tubes and may be of importance in tube nutrition. There was no degeneration in the unpollinated stigma and style and the cytoplasm did not start to lose clarity until 42 h after first opening of the flower.

The migration of lymphocytes across specialized vascular endothelium. II. The contrasting consequences of treating lymphocytes with tryspin or neuraminidase

Lymphocytes were exposed in vitro to either trypsin or neuraminidase. The ability of the treated cells to migrate into tissues were measured (a) by i.v. injection into intact recipients and (b) by vascular perfusion through an isolated lymph-node preparation. The localization of trypsinized cells in the lymph-nodes of recipients was deficient when compared to untreated lymphocytes and there was a surplus of trypsinized cells in blood. Trypsinized cells migrated into the isolated nodes in reduced numbers. By contrast, neuraminidase treated lymphocytes were markedly deficient in the blood of recipients early after injection; their localization in the spleen and lymph-nodes was also deficient but they were in surplus in the liver. Moreover they migrated into the isolated nodes in slightly increased numbers. By 24 hr after injection the perturbed localization pattern produced by either enzyme was partly restored to normal. In conclusion, tryspin interfered with the capacity of lymphocytes to migrate into lymph-nodes but neuraminidase did not; the latter promoted the hepatic sequestration of cells and the reduced localization in the blood and tissues was a consequence of this. The hypothesis that lymphocytes adhere to specialized endothelia in lymph-nodes because of specific glycoside sequences on their surface lacks experimental support.

The migration of lymphocytes across specialized vascular endothelium. I. The entry of lymphocytes into the isolated mesenteric lymph-node of the rat

The chain of lymph-nodes in the rat mesentery was isolated and the preparation was perfused via cannulae in the superior mesenteric vessels. The perfusate consisted of serum to which labelled lymphocytes had usually been added. The entry of radioactively labelled lymphocytes from the blood vessels into the lymph-nodes was studied by scintillation counting and autoradiography. It was observed that: (1) In the perfused node labelled lymphocytes localized in and around post-capillary venules in the paracortex as they do early after i.v. injection. (2) The number of lymphocytes which entered the node was directly proportional to the concentration in the perfusate over the range studied. The proportion of cells retained in the node varied considerably around a mean of 11% of lymphocytes reaching it. (3) The isolated lymph-node released few if any lymphocytes into the effluent (venous) perfusate. (4) Large lymphocytes migrated into isolated lymph-nodes slightly more readliy than did small lymphocytes. (5) Unlike intact cells isolated lymphocyte membranes did not adhere to specialized vascular endothelium.