Contributions of severe burn and disuse to bone structure and strength in rats.

Burn and disuse results in metabolic and bone changes associated with substantial and sustained bone loss. Such loss can lead to an increased fracture incidence and osteopenia. We studied the independent effects of burn and disuse on bone morphology, composition and strength, and microstructure of the bone alterations 14days after injury. Sprague-Dawley rats were randomized into four groups: Sham/Ambulatory (SA), Burn/Ambulatory (BA), Sham/Hindlimb Unloaded (SH) and Burn/Hindlimb Unloaded (BH). Burn groups received a 40% total body surface area full-thickness scald burn. Disuse by hindlimb unloading was initiated immediately following injury. Bone turnover was determined in plasma and urine. Femur biomechanical parameters were measured by three-point bending tests and bone microarchitecture was determined by micro-computed tomography (uCT). On day 14, a significant reduction in body mass was observed as a result of burn, disuse and a combination of both. In terms of bone health, disuse alone and in combination affected femur weight, length and bone mineral content. Bending failure energy, an index of femur strength, was significantly reduced in all groups and maximum bending stress was lower when burn and disuse were combined. Osteocalcin was reduced in BA compared to the other groups, indicating influence of burn. The reductions observed in femur weight, BMC, biomechanical parameters and indices of bone formation are primarily responses to the combination of burn and disuse. These results offer insight into bone degradation following severe injury and disuse.

Bone responses to body weight and moderate treadmill exercising in growing male obese (fa/fa) and lean Zucker rats.

OBJECTIVE: To evaluate if exercise in a young growing model of obesity would be able to reduce adiposity without adversely affecting bone. METHODS: Obese (fa/fa) and lean (Fa/Fa) male Zucker rats were randomly assigned (n=8-9 rats/group) to no exercise or to a moderate treadmill exercise regimen consisting of a speed of 20 m/min for approximately 1 h, 5 d/wk for 9 wks. Bone morphometry, total bone ash, and bone strength by three-point bending test were determined in the femur and the tibia. Serum alkaline phosphatase was determined using calorimetric enzyme assays. Serum osteocalcin, deoxypyridinoline (DPD), and pyridinoline (PYD) crosslinks were measured using enzyme immunoassays. Various blood chemistry measurements were determined including: serum glucose, insulin, and leptin. RESULTS: Growing obese (fa/fa) Zucker rats have long bone ash comparable to lean Zucker rats, although bone size is reduced. Moderate treadmill running successfully reduced body weight without increasing muscle mass, but did not attenuate the reduction in bone growth or promote greater bone mass and strength in obese Zucker rats. CONCLUSIONS: Moderate treadmill running for 9 wks successfully reduced the body weight of obese Zucker rats by 7.5% without negatively affecting bone.

Amino acid and mineral composition of protein and other components and their recovery yields from whole Antarctic krill (Euphausia superba) using isoelectric solubilization/precipitation.

Proteins and insolubles were recovered from whole Antarctic krill via novel isoelectric solubilization/precipitation using different pH treatments. The protein recovery yield was 45% to 50% (dry basis). The recovered proteins had higher (P < 0.05) content of essential amino acids (EAAs) and non-EAAs as well as higher (P < 0.05) ratio of total EAA/total AA than whole krill. The EAAs constituted almost 50% of total AAs. The least extreme pH treatments (pHs 3 and 12) yielded highest (P < 0.05) content of EAAs. The quality of recovered proteins was high based on EAAs meeting FAO/WHO/UNU recommendations for adults and infants. The basic pH yielded proteins with the lowest (P < 0.05) amount of minerals and the highest (P < 0.05) amount of Ca, P, and Mg in the insolubles when compared to the acidic treatments. However, both basic and acidic treatments effectively removed minerals from recovered proteins without the removal of the exoskeleton before processing. Therefore, besides high-quality proteins, the insolubles may provide a mineral supplement in the animal diet.

Amino acid, fatty acid, and mineral profiles of materials recovered from rainbow trout (Oncorhynchus mykiss) processing by-products using isoelectric solubilization/precipitation.

Protein, lipid, and insolubles (bones, skin, scales, fins, insoluble protein, and more) were recovered from rainbow trout processing by-products by means of isoelectric solubilization/precipitation at basic pH and acidic pH. Isoelectric solubilization/precipitation of the trout processing by-products resulted in the recovery of protein that was higher (P < 0.05) in essential amino acids (EAAs), non-EAAs, and total EAA/total AA ratio when compared to the processing by-products. Basic pH treatments yielded a higher (P < 0.05) content of EAAs than the acidic pH treatments. Nutritional quality of the recovered protein was high based on EAAs meeting the FAO/WHO/UNU recommendations for adults. The presence of omega-3 and omega-6 fatty acids (omega-3, omega-6 FAs) and the omega-3/omega-6 ratio in the recovered lipids were similar to the trout processing by-products, indicating that the pH treatments had no effect on these FAs. Ca and P contents of the processing by-products exceeded the recommended dietary allowances (RDA), but Fe and Mg did not. Basic pH treatments yielded protein with the lowest (P < 0.05) amount of minerals and the highest (P < 0.05) amount of Ca, P, and Mg in the insolubles when compared to acidic pH. The isoelectric solubilization/precipitation of the processing by-products effectively removed minerals from the recovered protein without removal of the bones, skin, scales, fins, and so on, prior to processing. The results indicated that isoelectric solubilization/precipitation, particularly at basic pH, permitted recovery of high-quality protein and lipids from fish processing by-products for human food uses; also, the recovered insolubles may be used in animal feeds as a source of minerals.

Exposure to flaxseed or its lignan component during different developmental stages influences rat mammary gland structures.

Reduction of the highly proliferative terminal end bud (TEB) structures in the developing mammary gland by differentiation to alveolar buds (ABs) and lobules has been suggested to be protective against mammary cancer. Flaxseed is high in alpha-linolenic acid (ALA) and secoisolariciresinol diglycoside (SDG). SDG is the precursor of mammalian lignans, which can affect mammary gland structures. Thus, the objective of this study was to determine the effect of lifetime, gestation and lactation or after-weaning exposure to 5 or 10% flaxseed or SDG and flaxseed oil components on the mammary gland structures of virgin female rat offspring at post-natal day 50. Lifetime or gestation and lactation exposure to flaxseed altered mammary gland structure development, whereas exposure to flaxseed after weaning had no effect. Lifetime or gestation and lactation exposure to 5% flaxseed caused endocrine changes, as suggested by delayed puberty onset and reduced number of estrous cycles. These changes reduced exposure to endogenous estrogens, leading to atrophy of mammary TEB structures. SDG, but not flaxseed oil, at the level found in 5% flaxseed produced similar effects as 5% flaxseed. This suggested that the lignans were the component in flaxseed responsible for the observed effects. Lifetime or gestation and lactation exposure to 10% flaxseed also caused endocrine changes, as suggested by early puberty onset and lengthened cycles due to prolonged estrus. This increased exposure to endogenous estrogens and stimulated mammary gland differentiation, as indicated by fewer TEBs and more ABs. Thus, lifetime or gestation and lactation exposure to 5 or 10% flaxseed induced structural changes in the mammary gland that may potentially reduce mammary cancer risk.

Dose, timing, and duration of flaxseed exposure affect reproductive indices and sex hormone levels in rats.

Flaxseed ingestion produces large amounts of mammalian lignans. Since lignans have weak estrogenic/antiestrogenic properties, the objective of this study was to determine in rats whether exposure to 5% or 10% flaxseed affects sex hormone levels and reproductive indices when given at different developmental stages. Rats were exposed to either a basal diet (control), 5%, or 10% flaxseed diet starting at weaning on postnatal day (PND) 21 or continuously from gestation to PND 132 for lifetime exposure. Compared to the control, exposure to 5% or 10% flaxseed after weaning produced no marked reproductive effects, whereas lifetime flaxseed exposure caused significant changes that differed depending on the dose. In female rats, lifetime exposure to 5% flaxseed affected the reproductive tract as indicated by delayed puberty onset. In contrast, lifetime exposure to 10% flaxseed caused earlier puberty onset, higher relative ovarian weight, higher serum estradiol levels, and lengthened estrous cycles. In male rats, lifetime 10% flaxseed exposure raised serum testosterone and estradiol levels and produced higher relative sex organ weights and prostate cell proliferation. In contrast, lifetime exposure to 5% flaxseed reduced adult relative prostate weight and cell proliferation, suggesting potential protection against prostatic disease, although sex hormone levels were unaffected. In conclusion, flaxseed can potentially alter reproduction, depending on the dose and timing of exposure.

Flaxseed and its lignan precursor, secoisolariciresinol diglycoside, affect pregnancy outcome and reproductive development in rats.

Flaxseed is the richest source of the mammalian lignan precursor secoisolariciresinol diglycoside (SDG). Because lignans have estrogen agonist or antagonist properties, the objective of this study was to determine whether feeding flaxseed to rats during a hormone-sensitive period has reproductive effects. Rat dams were fed a basal diet or the basal diet supplemented with 10% flaxseed, 5% flaxseed or SDG at the level in 5% flaxseed during pregnancy and lactation. At weaning, the offspring were fed the basal diet. Flaxseed had no effect on pregnancy outcome except that the 10% flaxseed diet lowered birth weight (P < 0.05), compared with other treatments, and produced hormonal effects. The female offspring had shortened anogenital distance, greater uterine and ovarian relative weights, earlier age and lighter body weight at puberty, lengthened estrous cycle and persistent estrus (P < 0.05), whereas the males had reduced postnatal weight gain and, at postnatal d 132, greater sex gland and prostate relative weights (P < 0.05), suggesting estrogenic effects. In contrast, compared with the basal diet, 5% flaxseed reduced immature ovarian relative weight by 29% (P < 0.05), delayed puberty by approximately 5 d (P < 0.05) and tended to lengthen diestrus, indicating an antiestrogenic effect. The SDG produced results similar to those of 5% flaxseed, suggesting that lignans were responsible for the observed effects. Lignans were transferred to the offspring via rat dam's milk as indicated by the recovery of radioactivity in the offspring of lactating dams given 3H-SDG. Because flaxseed affects the reproductive development of offspring, caution is suggested when consuming flaxseed during pregnancy and lactation.

Valved sampling cell for membrane introduction mass spectrometry.

Membrane extractors comprising a membrane house inside of a valve have been developed to separate compounds of interest from a sample matrix and introduce these compounds into a mass spectrometer. Experimental control over parameters that affect permeability or that may damage the membrane, such as the membrane temperature, is provided with the valve. The valve was tested for response and response times with the valve separated from the mass spectrometer by various interface tube lengths. Data for steady state response measurements showed no significant change with the valve at different distances from the ion source. Polar compounds show a strong response time dependency on the interface tube length. This adsorption phenomenon is minimized by simply heating the interface tube. Other factors affecting the performance of the device are discussed.

Stability studies of alkoxysilanes in aqueous media.

In order to correlate hydrolysis rates under physiological conditions to differences in toxicity of trimethoxysilane, tetramethoxysilane, and methyltrimethoxysilane, the rates of hydrolysis of these compounds were studied in deionized water, sodium phosphate buffer solution at pH 7.4, and 10% rat serum in sodium phosphate buffer at 37.4 degrees C. A strong surface effect was observed on the hydrolysis rates of tetramethoxysilane in different reactors in the following decreasing order: quartz greater than soft glass (I) greater than stainless steel greater than Teflon greater than soft glass (II). By using the soft glass (II) reactor as the reaction vessel for hydrolysis experiments, trimethoxysilane and tetramethoxysilane were found to be very unstable in 0.15 M sodium phosphate buffer (pH 7.4) and 10% rat serum (0.15 M sodium phosphate buffer, pH 7.4) with similar rates of hydrolysis at greater than 3.0 min-1 (t 1/2 less than 0.23 min). Under similar conditions, however, the rate of hydrolysis for tetramethoxysilane in deionized water was measured to be considerably slower (k = 0.022 min-1; t 1/2 = 32 min) than that of trimethoxysilane (k greater than 8.1 min-1, t 1/2 less than 0.09 min). However, the rates of hydrolysis for methyltrimethoxysilane in water, sodium phosphate buffer at pH 7.4, and 10% rat serum were measured to be 0.03 min-1 (t 1/2 = 24 min), 0.10 min-1 (t 1/2 = 6.7 min), and 0.08 min-1 (t 1/2 = 8.6 min), respectively.

Some industrial developments and applications of multidimensional techniques.

Industrial analytical chemistry includes the measurement of the elemental composition and structure of molecules; the measurement of the concentration of specific molecules, atoms, and ions in contact with other molecules, atoms, and ions, the measurement of the energy and speed with which these reactions occur; and the separation of molecules, atoms, and ions specifically from other molecules, atoms and ions. It is also the measurement of the physical (interaction) and chemical (reaction) behavior of collections of molecules and how this behavior is controlled by the presence of other molecules and ions. Many excellent devices for separation and measurement have been developed to accomplish these tasks. Each of these attains a level of sensitivity and selectivity beyond which further improvement would be difficult. However, by coupling these techniques in various configurations, improved data can be generated in a short time span. Such techniques are often referred to as hyphenated, tandem, combined, or coupled. A more inclusive term is multidimensional techniques. In this paper, we briefly describe some of the most significant developments our laboratory has made in these and related techniques.