Dimensional Changes of Tracheids during Drying of Radiata Pine (Pinus radiata D. Don) Compression Woods: A Study Using Variable-Pressure Scanning Electron Microscopy (VP-SEM).

Variable-pressure scanning electron microscopy was used to investigate the dimensional changes in longitudinal, tangential and radial directions, on wetting and drying, of tracheids of opposite wood (OW) and three grades of compression woods (CWs), including severe CW (SCW) and two grades of mild compression wood (MCW) (MCW1 and MCW2) in corewood of radiata pine (Pinus radiata) saplings. The CW was formed on the underside and OW on the upper side of slightly tilted stems. In the longitudinal direction, the shrinkage of SCW tracheids was ~300% greater than that of OW tracheids, with the shrinkage of the MCW1 and MCW2 tracheids being intermediate. Longitudinal swelling was also investigated and hysteresis was demonstrated for the tracheids of all corewood types, with the extent of hysteresis increasing with CW severity. A statistical association was found between longitudinal shrinkage and the content of lignin and galactosyl residues in the cell-wall matrix. The galactosyl residues are present mostly as (1→4)-ß-galactans, which are known to have a high capacity for binding water and swell on hydration. The small proportions of (1→3)-ß-glucans in the CWs have similar properties. These polysaccharides may play a functional role in the longitudinal shrinking and swelling of CW tracheids. Tangential shrinkage of tracheids was greater than radial shrinkage but both were greatest for OW and least for SCW, with the MCW1 and MCW2 being intermediate.

Location and characterization of lignin in tracheid cell walls of radiata pine (Pinus radiata D. Don) compression woods.

Tilted stems of softwoods form compression wood (CW) and opposite wood (OW) on their lower and upper sides, respectively. More is known about the most severe form of CW, severe CW (SCW), but mild CWs (MCWs) also occur widely. Two grades of MCWs, MCW1 and MCW2, as well as SCW and OW were identified in the stems of radiata pine (Pinus radiata) that had been slightly tilted. The four wood types were identified by the distribution of lignin in the tracheid walls determined by fluorescence microscopy. A solution of the fluorescent dye acridine orange (AO) (0.02% at pH 6 or 7) was shown to metachromatically stain the tracheid walls and can also be used to determine lignin distribution. The lignified walls fluoresced orange to yellow depending on the lignin concentration. Microscopically well-characterized discs (0.5 mm diameter) of the wood types were used to determine lignin concentrations and lignin monomer compositions using the acetyl bromide method and thioacidolysis, respectively. Lignin concentration and the proportion of p-hydroxyphenyl units (H-units) relative to guaiacyl (G-units) increased with CW severity, with <1% H-units in OW and up to 14% in SCW. Lignin H-units can be used as a marker for CW and CW severity. Similar discs were also examined by Raman and FTIR micro-spectroscopies coupled with principal component analysis (PCA) to determine if these techniques can be used to differentiate the four different wood types. Both techniques were able to do this, particularly Raman micro-spectroscopy.

Tracheid cell-wall structures and locations of (1 → 4)-ß-D-galactans and (1 → 3)-ß-D-glucans in compression woods of radiata pine (Pinus radiata D. Don).

BACKGROUND: Compression wood (CW) forms on the underside of tilted stems of coniferous gymnosperms and opposite wood (OW) on the upperside. The tracheid walls of these wood types differ structurally and chemically. Although much is known about the most severe form of CW, severe CW (SCW), mild CWs (MCWs), also occur, but less is known about them. In this study, tracheid wall structures and compositions of two grades of MCWs (1 and 2) and SCW were investigated and compared with OW in slightly tilted radiata pine (Pinus radiata) stems. RESULTS: The four wood types were identified by the distribution of lignin in their tracheid walls. Only the tracheid walls of OW and MCW1 had a S3 layer and this was thin in MCW1. The tracheid walls of only SCW had a S2 layer with helical cavities in the inner region (S2i). Using immunomicroscopy, (1 → 4)-ß-D-galactans and (1 → 3)-ß-D-glucans were detected in the tracheid walls of all CWs, but in only trace amounts in OW. The (1 → 4)-ß-D-galactans were located in the outer region of the S2 layer, whereas the (1 → 3)-ß-D-glucans were in the inner S2i region. The areas and intensities of labelling increased with CW severity. The antibody for (1 → 4)-ß-D-galactans was also used to identify the locations and relative amounts of these galactans in whole stem cross sections based on the formation of an insoluble dye. Areas containing the four wood types were clearly differentiated depending on colour intensity. The neutral monosaccharide compositions of the non-cellulosic polysaccharides of these wood types were determined on small, well defined discs, and showed the proportion of galactose was higher for CWs and increased with severity. CONCLUSION: The presence of an S3 wall layer is a marker for very MCW and the presence of helical cavities in the S2 wall layer for SCW. The occurrence and proportions of (1 → 4)-ß-D-galactans and (1 → 3)-ß-D-glucans can be used as markers for CW and its severity. The proportions of galactose were consistent with the labelling results for (1 → 4)-ß-D-galactans.

Evidence of enhanced serum amino acid profile but not appetite suppression by dietary glycomacropeptide (GMP): a comparison of dairy whey proteins.

OBJECTIVE: There is evidence that high-protein foods increase satiety and may aid weight loss, yet little is known of differential effects of protein composition. The aim of the study was to compare the acute effects of 4 whey proteins on satiety and food intake and to evaluate possible relationships with postprandial serum amino acid concentrations. METHODS: Isoenergetic high-protein shakes (∼1 MJ) containing 25 g whey protein were given to 18 lean male participants using a crossover design. Three protein fractions identified as satiating in a rat model, glycomacropeptide (GMP), beta-lactoglobulin (ß-lac), and colostrum whey protein concentrate (WPC), were compared with a WPC control. A standardized 2.5MJ breakfast was given at 0830 hours, followed by the preload beverages at 1130 hours. Participants rated appetite sensations using visual analogue scales (VAS) prior to the beverage (baseline, 0 minutes) and then at 15, 30, 45, 60, 90, 150, and 210 minutes. Energy and macronutrient intake was measured by covert weighing of an ad libitum lunch meal at 90 minutes. Repeat blood samples were collected via venous cannulation. RESULTS: Serum amino acid (a.a.) concentrations differed between whey fractions (p=0.012) and were higher following GMP compared to ß-lac (p=0.051) and colostrum WPC (p=0.044) but not the WPC control (p=0.20). There was no difference in VAS-rated hunger, satisfaction, or thoughts of food between whey fractions, but fullness did differ (p=0.032) and was highest following the ß-lac beverage. Energy intake was not suppressed relative to control by any of the 3 whey fractions. CONCLUSIONS: We conclude that total serum a.a. concentration was a poor indicator of satiety, with little evidence of differential satiety between these whey proteins other than a modest enhancement of fullness by ß-lac.

Histomorphometric evaluation of the effect of early exercise on subchondral vascularity in the third carpal bone of horses.

OBJECTIVE: To investigate histomorphometric changes in the cartilage and subchondral bone of the third carpal bone associated with conditioning exercise in young Thoroughbreds. ANIMALS: Nine 18-month-old Thoroughbreds. Procedures-Both third carpal bones of 9 horses (4 exercised spontaneously at pasture only and 5 given additional conditioning exercise beginning at a mean age of 3 weeks) were evaluated. Histomorphometric variables (hyaline and calcified cartilage thickness and collagen orientation; vascular channel area, number, and orientation; and osteochondral junction rugosity) of the third carpal bone, sampled at 4 dorsopalmar sites in the radial facet, were compared between the exercised and nonexercised groups. RESULTS: The vascular channel area measured at the 4 dorsopalmar sites was larger in the exercised group than in the control group, but none of the variables were significantly different between groups. Both groups had significant site-specific variations in all measured variables. Most importantly, the vascular channel area was highest in the most dorsal aspect. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that the mild exercise imposed in both groups during the developmental period appeared to be associated with an increase in the vascular channel area beneath the calcified cartilage layer in the third carpal bone. This increased vascular channel area could also be associated with high stress in the dorsal aspect of the radial facet, a region that is known to be vulnerable to osteochondral fragmentation.

No evidence of differential effects of SFA, MUFA or PUFA on post-ingestive satiety and energy intake: a randomised trial of fatty acid saturation.

BACKGROUND: High fat diets have long been associated with weight gain and obesity, and the weak satiety response elicited in response to dietary lipids is likely to play a role. Suppression of appetite and food intake has consistently been shown to be diminished with high fat relative to either high protein or carbohydrate meals. There is however some evidence that the satiating capacity of lipids may be modulated when physicochemical properties are altered, but studies investigating the effect of lipid saturation on appetite have generated inconsistent findings. This study investigated the effects of changes in fatty acid saturation on post-ingestive satiety and energy intake. METHODS: High-fat (HF) test breakfasts (2.0 MJ) containing 26 g lipid were given to 18 healthy, lean men in a 3 treatment randomised cross-over design, each treatment separated by a washout of at least 3 days. The breakfasts were high in saturated (SFA, 65% of total fat), polyunsaturated (PUFA, 76%) or monounsaturated (MUFA, 76%) fatty acids, and comprised 2 savoury muffins. Participants rated appetite sensations using visual analogue scales (VAS) to assess palatability immediately following the meals, and hunger and fullness prior to the HF breakfast and throughout the day. Energy intake was measured by covert weighing of a lunch meal which was served 3.5 h after the breakfast, and from which the participants ate ad libitum. RESULTS: There was no difference in VAS ratings of pleasantness, visual appearance, smell, taste, aftertaste and overall palatability between the 3 high-fat test breakfasts. However, there was also no differential effect of the 3 treatments on ratings of hunger, fullness, satisfaction or prospective food consumption during the 3.5 h following the breakfast meal and over the full 6 h experiment. Energy and macronutrient intake at lunch also did not differ between treatments (mean, sem; SFA: 5275.9 +/- 286.5 kJ; PUFA: 5227.7 +/- 403.9 kJ; MUFA: 5215.6 +/- 329.5 kJ; P > 0.05). The maximum difference in energy intake between treatments was less than 2%. CONCLUSIONS: There was no evidence of a difference in post-ingestion satiety between high fat meals which differed in saturation profile in this group of lean, healthy men.

Influence of early conditioning exercise on the development of gross cartilage defects and swelling behavior of cartilage extracellular matrix in the equine midcarpal joint.

OBJECTIVE: To investigate the influence of early conditioning exercise on the development of gross cartilage defects and swelling behavior of cartilage extracellular matrix (ECM) in the midcarpal joint of horses. ANIMALS: 12 Thoroughbreds. PROCEDURES: 6 horses underwent early conditioning exercise from birth to 18 months of age (CONDEX group), and 6 horses were used as control animals (PASTEX group). The horses were euthanized at 18 months of age, and the midcarpal joints were harvested. Gross defects of the cartilage surface were classified and mapped. Opposing surfaces of the third and radial carpal bones were used to quantify swelling behavior of the cartilage ECM. RESULTS: A wide range of gross defects was detected in the cartilage on the opposing surfaces of the bones of the midcarpal joint; however, there was no significant difference between the CONDEX and PASTEX groups. Similarly, no significant difference in swelling behavior of the cartilage ECM was evident between the CONDEX and PASTEX groups. CONCLUSIONS AND CLINICAL RELEVANCE: In the study reported here, we did not detect negative influences of early conditioning exercise on the prevalence of gross defects in cartilage of the midcarpal joint or the quality of the cartilage ECM as defined by swelling behavior. These results suggested that early conditioning exercise may be used without negative consequences for the midcarpal joint and the cartilage ECM of the third and radial carpal bones.

Postprandial response of adiponectin, interleukin-6, tumor necrosis factor-alpha, and C-reactive protein to a high-fat dietary load.

OBJECTIVE: Circulating levels of adiponectin are low in obesity and metabolic disorders associated with increasing fat mass including insulin resistance and dyslipidemia. Body fat stores may be positively related to intake of dietary fat, but little is known of mechanisms by which serum adiponectin may be regulated through diet. We investigated acute effects of a high-fat load and changes in fatty acid saturation on circulating adiponectin and associated mediators of inflammation including interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and C-reactive protein (CRP). METHODS: A high-fat test meal (59 +/- 4 g fat; 71% of energy as fat) containing a high ( approximately 71:29) or low ( approximately 55:45) ratio of saturated:unsaturated fatty acids was given at breakfast on two occasions. Blood samples were collected at 0 (baseline), 1, 3, and 6 h for measurement of adiponectin, IL-6, TNF-alpha, and high-sensitivity CRP. A fat-exclusion lunch, snack, and dinner were also given and blood samples collected at 10 and 24 h. RESULTS: Eighteen healthy, lean men completed the trial. There was no evidence of acute change in circulating adiponectin in response to the lipid bolus or a differential effect of fatty acid saturation on adiponectin, high-sensitivity CRP, or IL-6 (P > 0.05). IL-6 increased over 6 h on both treatments (time, P < 0.05). TNF-alpha decreased on the high saturated:unsaturated fatty acid treatment (treatment by time, P < 0.05). There were no significant correlations between circulating adiponectin and insulin on either dietary treatment in these normoglycemic subjects. CONCLUSION: Acute changes in the content of saturated and unsaturated fatty acids had no adverse effect on postprandial circulation of the adipose-related factors adiponectin, IL-6, TNF-alpha, or high-sensitivity CRP.

No evidence of an effect of alterations in dietary fatty acids on fasting adiponectin over 3 weeks.

OBJECTIVE: Little is known about the effects of alterations in fatty acid classes on adiponectin, a hormone secreted by the adipocyte known to be important in the development of diabetes and cardiovascular disease (CVD). Any factor, including diet, that may positively influence adiponectin gene expression or increase circulating levels might be useful for improving such metabolic abnormalities. We investigated the effects of alterations in dietary fatty acid saturation on fasting serum adiponectin and associated peptides. METHODS AND PROCEDURES: Double-blind, randomized, crossover, 2 x 3-week residential intervention trial where 18 mildly hyperlipidemic adult men were provided with a high saturated:unsaturated fat (SFA:USFA) and lower SFA:USFA treatment separated by an uncontrolled 4-week washout. Only fatty acid profile was altered between treatments. Fasting blood samples were collected on days 0, 1, 7, 14, 21, 22 of each intervention period for the measurement of adiponectin, tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), high-sensitivity C-reactive protein (hsC-RP), leptin, and ghrelin. RESULTS: Body weight was kept constant (+/-1 kg) throughout each treatment. There was no detectable difference in fasting adiponectin at baseline (mean day 0 + day 1) between the treatment groups (mean +/- s.d.; high(SFA:USFA) = 7.0 +/- 1.7 vs. low(SFA:USFA) = 6.7 +/- 1.4 microg/ml, P > 0.05). There were neither significant between-treatment effects of fatty acid saturation (diet x time, P > 0.05) on serum adiponectin nor any significant between-treatment effects on serum TNF-alpha, IL-6, hsC-RP, leptin, or ghrelin (P > 0.05). DISCUSSION: Fasting serum adiponectin was not detectably affected by alterations in dietary fatty acid profile in mildly hyperlipidemic men. There was no evidence that an increase in SFA content of the diet significantly worsened fasting serum adiponectin over a 3-week intervention period.

Multivariate dispersion as a measure of beta diversity.

Beta diversity can be defined as the variability in species composition among sampling units for a given area. We propose that it can be measured as the average dissimilarity from individual observation units to their group centroid in multivariate space, using an appropriate dissimilarity measure. Differences in beta diversity among different areas or groups of samples can be tested using this approach. The choice of transformation and dissimilarity measure has important consequences for interpreting results. For kelp holdfast assemblages from New Zealand, variation in species composition was greater in smaller holdfasts, while variation in relative abundances was greater in larger holdasts. Variation in community structure of Norwegian continental shelf macrobenthic fauna increased with increases in environmental heterogeneity, regardless of the measure used. We propose a new dissimilarity measure which allows the relative weight placed on changes in composition vs. abundance to be specified explicitly.

Randomized controlled crossover study of the effect of a highly beta-glucan-enriched barley on cardiovascular disease risk factors in mildly hypercholesterolemic men.

BACKGROUND: Soluble-fiber beta-glucan derived from oats can reduce cardiovascular disease (CVD) risk through reductions in total and LDL cholesterol. Barley-derived beta-glucan may also improve serum cholesterol, but large quantities are required for clinical significance. OBJECTIVE: This trial investigated whether a beta-glucan-enriched form of barley can favorably modify cholesterol and other markers of CVD and diabetes risk. DESIGN: Eighteen mildly hyperlipidemic ( +/- SD: 4.0 +/- 0.6 mmol LDL cholesterol/L) men with a mean (+/- SD) body mass index (in kg/m(2)) of 27.4 +/- 4.6 were randomly assigned in this single-blind, 2 x 4-wk trial to either the treatment arm [8.1-11.9 g beta-glucan/d (scaled to body weight)] or the control arm (isoenergetic dose of 6.5-9.2 g glucose/d). After a washout period of 4 wk, dietary regimens were crossed over. The trial took place in a long-stay metabolic facility, and all foods were provided (38% of energy from fat). Fasted blood samples were collected on days 0, 1, 7, 14, 21, 28, and 29 in both study arms. An oral-glucose-tolerance test was carried out on days 0 and 29. RESULTS: There was no significant change (Delta) in total (Delta = -0.08 mmol/L, -1.3%), LDL (Delta = -0.15 mmol/L, -3.8%), or HDL (Delta = 0 mmol/L) cholesterol or in triacylglycerol (Delta = 0.18 mmol/L), fasting glucose (Delta = -0.05 mmol/L), or postprandial glucose when analyzed between treatments (P > 0.05; ANOVA). CONCLUSION: The effect of beta-glucan-enriched barley on lipid profile was highly variable between subjects, and there was no evidence of a clinically significant improvement in CVD risk across this group of mildly hyperlipidemic men.