An evaluation of transovarian uptake of metabolites using arterio-venous difference methods in dairy cattle

Arterio-venous (A-V) difference techniques were used in cattle to examine ovarian energy metabolism, cholesterol uptake and steroid hormone outputs. Catheters were inserted into the ovarian vein and facial artery, and Transonic flow transducers were placed around the ovarian A-V plexus. Further, in some cows, the effects of a challenge with GnRH were examined. Glucose uptake and lactate output were significant in most individual cows. Nonesterified fatty acids (NEFA) uptake were not significant in any cow in dioestrus. Ovarian uptake of beta-Hydroxy-butyrate (3-OHB) was significant in 4 cows in dioestrus. Cholesterol uptake was significant in only 1 cow. Oxygen uptake was significant in all cows at all stages of the oestrous cycle. All cows had significant output of progesterone and oestradiol-17 beta. These data show that the bovine ovary utilises significant amounts of glucose, and Respiratory quotient (RQ) estimates demonstrated that glucose was the primary fuel used by the ovary. The significant output of lactate suggested that anaerobic pathways were mainly used for glucose oxidation. The observed uptakes of 3-OHB indicated that the ovary utilises 3-OHB as a source of energy. Cholesterol uptake was not a rate-limiting factor for steroid hormone production in the ovary. Despite the high metabolic rate in the luteal ovary, the small difference in PO2 between arterial and ovarian venous blood indicated that the ovary consumes only a small proportion of available oxygen. GnRH had no significant effect on the uptake of metabolites and energy metabolism, but it increased OBF and the output of progesterone and oestradiol-17 beta. The use of A-V methods to determine the metabolic needs of the ovary is useful in understanding the means by which nutrition can influence fertility.     

Protection of low density lipoprotein oxidation at chemical and cellular level by the antioxidant drug dipyridamole

1. The oxidative modification of low density lipoprotein (LDL) is thought to be an important factor in the initiation and development of atherosclerosis. Natural and synthetic antioxidants have been shown to protect LDL from oxidation and to inhibit atherosclerosis development in animals. Synthetic antioxidants are currently being tested, by they are not necessarily safe for human use. 2. We have previously reported that dipyridamole, currently used in clinical practice, is a potent scavenger of free radicals. Thus, we tested whether dipyridamole could affect LDL oxidation at chemical and cellular level. 3. Chemically induced LDL oxidation was made by Cu(II), Cu(II) plus hydrogen peroxide or peroxyl radicals generated by thermolysis of 2,2'-azo-bis(2-amidino propane). Dipyridamole, (1-10 microM), inhibited LDL oxidation as monitored by diene formation, evolution of hydroperoxides and thiobarbituric acid reactive substances, apoprotein modification and by the fluorescence of cis-parinaric acid. 4. The physiological relevance of the antioxidant activity was validated by experiments at the cellular level where dipyridamole inhibited endothelial cell-mediated LDL oxidation, their degradation by monocytes, and cytotoxicity. 5. In comparison with ascorbic acid, alpha-tocopherol and probucol, dipyridamole was the more efficient antioxidant with the following order of activity: dipyridamole > probucol > ascorbic acid > alpha-tocopherol. The present study shows that dipyridamole inhibits oxidation of LDL at pharmacologically relevant concentrations. The inhibition of LDL oxidation is unequivocally confirmed by use of three different methods of chemical oxidation, by several methods of oxidation monitoring, and the pharmacological relevance is demonstrated by the superiority of dipyridamole over the naturally occurring antioxidants, ascorbic acid and alpha-tocopherol and the synthetic antioxidant probucol.     

Ischemic heart disease and stroke mortality in African-American, Hispanic, and non-Hispanic white men and women, 1985 to 1991

Electrochemiluminescence (ECL) of 200 ppm 2,3-diaminonaphthalene (2,3-DAN) was studied alone and in conjunction with 100 ppm of 34 different metal and non-metal ions and revealed three relatively intense ECL responses from interactions of 2,3-DAN with Au+, Fe+3 and V+5. ECL responses from Cr+6 or Ru+3 with 2,3-DAN were less intense, but noteworthy, as was the coloured fluorescent product of the non-metal ion Se+4 interaction with 2,3-DAN. Several intense 2,3-DAN-metal ion ECL reactions were studied in greater detail and revealed various titration curves with ionic detection limits in the low ppm range, using a fixed level (200 ppm) of 2,3-DAN.     

Relapsing cutaneous polyarteritis nodosa associated with streptococcal infections

BACKGROUND: Polyarteritis nodosa is an aggressive, often fatal form of vasculitis associated with multi-organ involvement. Cutaneous polyarteritis nodosa is purported to be a more benign form of this disorder with involvement limited to the skin. METHODS: The identification of a female patient from childhood to adulthood documenting repeated episodes of cutaneous polyarteritis nodosa following bouts of recurrent streptococcal pharyngitis. RESULTS: Repeated bouts of streptococcal pharyngitis at ages 11, 28, and 33 years were followed by episodes of cutaneous polyarteritis nodosa, documented by histopathologic skin changes and clinical presentation, and confirmed by therapeutic management. CONCLUSIONS: Various infectious and non-infectious conditions have been linked both to the initiation and relapse of this disease. We describe a patient with recurrent episodes of cutaneous polyarteritis nodosa spanning a period of over 20 years with each episode appearing to be linked to a prior streptococcal infection.     

Thermodynamics-based alloy design criteria for austenite stabilization and transformation toughening in the Fe---Ni---Co system

Transformation toughening has been widely applied in metastable austenitic steels. Recently this toughening mechanism has been extended to ultrahigh strength secondary-hardening martensitic steels, bearing suitable austenitic dispersions. The resulting dispersed-phase transformation toughening depends on the stability of the austenitic dispersions. The stability of dispersed austenite depends on various factors including the chemical composition and size of austenite particles, the stress state and the yield strength of the matrix. A single-parameter characterization of the stability of the austenitic dispersion is provided by the M_s^σ temperature and a functional form relating that temperature with the above-mentioned factors is developed. The microstructural requirements for dispersed-phase transformation toughening are then derived in terms of the austenite particle size and chemical enrichment in stabilizing solutes. Compositional effects on austenite stability have been studied by performing thermodynamic calculations using the Thermo-Calc software. The free-energy change ΔG^ch = G^b.c.c. − G^f.c.c. for martensitic transformation (a measure of austenite stability) has been evaluated as a function of composition in the ternary Fe---Ni---Co system. This information, when superimposed on isothermal sections at the tempering temperatures of interest, provides a way for selecting alloy compositions that maximize the thermodynamic stability of dispersed austenite.     

Changes in surface conditions with first plasma in the princeton large torus (PLT)

We report in-situ measurements of the changes in surface composition of 305 stainless steel exposed to the first plasma discharges in PLT. Auger electron spectroscopy of pre-exposure surfaces shows a contamination by carbon and smaller amounts of oxygen. Surfaces subjected to increasing levels of plasma exposure show a substantial decrease of the carbon coverage, increased fractional-monolayer coverages of oxygen and iron and tenth-monolayer quantities of chlorine and sulfur.     

Personal and peers' word associations in relation to children's false recognition errors.

Attempted to show that false recognition errors would be more frequently elicited by children's personal associates to a set of target words than by associates based on peer norms; Ss were 80 White middle-class 2nd and 5th graders (mean ages, 7.6 and 10.6 yrs, respectively). In Session 1 Ss gave oral associations to 34 words. In the 1st phase of Session 2, target words were each read aloud once and Ss were required to memorize them; in the 2nd phase Ss worked for 5 min on a maze task to prevent rehearsal; and in the final phase, a 40-item recognition list was read. Ss determined whether a word was one they had been asked to remember. As predicted, responses occurred with decreasing frequency to target, personal, peer, and control words. Consistent with the expectation that personal associates would more frequently elicit false recognition errors than would peer associates, the difference between personal and control responses was larger than the difference between peer and control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)