Effect of prepartum anionic supplementation on periparturient feed intake, health, and milk production.

Our objectives were to determine if dietary cation-anion difference (DCAD) and source of anions influence periparturient feed intake and milk production of dairy cattle during the transition period. Diets differed in DCAD (cationic or anionic) and anionic supplement. The 4 diets used prepartum were (1) control [DCAD +20 mEq/100g of dry matter (DM)], (2) Bio-Chlor (DCAD -12 mEq/100g of DM; Church & Dwight Co. Inc., Princeton, NJ), (3) Fermenten (DCAD -10 mEq/100g of DM; Church & Dwight Co. Inc.), and (4) salts (DCAD -10 mEq/100g of DM). Urine pH was lower for cows that consumed an anionic diet prepartum compared with control. Prepartum diet had no effect on prepartum dry matter intake (DMI) of multiparous or primiparous cows. Postpartum DMI and milk yield for multiparous cows fed anionic diets prepartum were greater compared with those fed the control diet. Postpartum DMI and milk yield of primiparous cows were similar for prepartum diets. Feeding prepartum anionic diets did not affect plasma Ca at or near calving. However, cows fed anionic diets began their decline in plasma Ca later than control cows. Postpartum ß-hydroxybutyrate and nonesterified fatty acids were lower for primiparous cows fed prepartum anionic diets compared with those fed the control diet. Prepartum and postpartum plasma glucose concentrations were not affected by prepartum diet for all cows. Liver triglyceride differed for parity by day. Parities were similar at 21 d prepartum, but at 0 d and 21 d postpartum, levels were greater for multiparous cows. Results indicate that decreasing the DCAD of the diet during the prepartum period can increase postpartum DMI and milk production of multiparous cows without negatively affecting performance of primiparous cows.

Trialkylphosphine-stabilized copper-phenyltellurolate complexes: from small molecules to nanoclusters via condensation reactions.

Reactions of CuCl with Te(Ph)SiMe3 and solublizing trialkylphosphine ligands afford a series of polynuclear copper-phenyltellurolate complexes that has been structurally characterized. The formation of the complexes is found to be highly dependent on the ancillary phosphine ligand used. The synthesis and structures of [Cu2(mu-TePh)2(PMe3)4] 1, [Cu4(mu3-TePh)4(PPr(i)3)3] 2, [Cu5(mu-TePh)3(mu3-TePh)3(PEt3)3][PEt3Ph] 3, and [Cu12Te3(mu3-TePh)6(PEt3)6] 4 are described. The telluride (Te(2-)) ligands in 4 arise from the generation of TePh2 in the reaction mixtures. The subsequent co-condensation of clusters 3 and 4 leads to the generation of the nanometer sized complex [Cu29Te9(mu3-TePh)10(mu4-TePh)2(PEt3)8][PEt3Ph] 5 in good yield, in addition to small amounts of [Cu39(mu3-TePh)10(mu4-TePh)Te16(PEt3)13] 6. These complexes are formed via the photo elimination of TePh2. The cyclic voltammogram of 5 in THF solution exhibits two oxidation waves, assigned to the oxidation of the Cu(I) centers.

Internal iliac artery embolization in the stent-graft treatment of aortoiliac aneurysms: analysis of outcomes and complications.

PURPOSE: To analyze the complications of internal iliac artery (IIA) embolization in conjunction with stent-graft treatment of aortoiliac aneurysms. MATERIALS AND METHODS: Seventy-one patients with aortoiliac (n = 47) or iliac (n = 24) aneurysms were treated with endoluminal placement of stent-grafts. Thirty-two patients (31 men, one woman; mean age, 73 years; range, 56-88 years) had embolization or occlusion of one (n = 27) or both (n = 5) IIAs. Status of the IIAs and the collateral circulation was assessed by retrospective review of angiographic images. Follow-up consisted of a standardized patient questionnaire and review of radiologic and medical records. RESULTS: The mean follow-up time was 35 months (range, 5-64 months). Eleven of the 47 patients with abdominal aortic aneurysms (AAA) (23%) and 19 of the 24 patients with iliac aneurysms (79%) required IIA embolization. One patient with AAA and another with iliac aneurysm had unintentional occlusion of an IIA by extension of the stent-graft over their origins. A total of seven patients had bilateral occlusion of the IIAs after the procedure. Additionally, the inferior mesenteric arteries (IMAs) of two other patients with AAA were also embolized. In six patients, all three vessels were occluded after placement of the stent-grafts. Symptoms were reported in nine of the 20 (45%) patients with iliac aneurysms and in three of the 12 (25%) patients with AAA. Symptoms consisted of buttock claudication (nine of 32, 28%), new sexual dysfunction (two of 16, 12%), and transient urinary retention (3%). Seven of the claudicants had resolution of symptoms after a mean interval of 14 months (range, 1-36 months). There were no instances of bowel ischemia, neurologic sequelae, or buttock necrosis related to these procedures. CONCLUSION: Embolization of the IIA is associated with symptoms in a significant number of patients. While symptoms are transient in most patients, they can be problematic. Efforts should be made to preserve the pelvic circulation if possible.

Pyruvate and lactate metabolism in the in vivo dog heart.

Pyruvate increases the phosphorylation potential in perfused heart to a greater extent than the closely correlated substrate L-lactate. Therefore, metabolism of these compounds was studied in the myocardium of intact dogs. Phosphocreatine/ATP was increased 23% at 5.3 mM plasma pyruvate but was not significantly increased by lactate except at the highest concentration (17.5 mM in blood). Calculated [ADP] fell during pyruvate infusion from 51.5 +/- 2.0 to 38.6 +/- 3.3 microM but did not change significantly during lactate infusion. Intracellular free [Mg2+] fell from 705 +/- 53 to 498 +/- 30 microM at the highest pyruvate infusion and from 692 +/- 112 to 417 +/- 19 microM with lactate infusion. Extraction of both substrates was linear at low concentrations, reaching 0.56 mumol lactate.min-1.g wet wt-1 at 17.5 mM blood lactate and 0.58 mumol pyruvate.min-1.g wet wt-1 at 5.3 mM plasma pyruvate. Therefore, lactate uptake was almost five times lower than pyruvate uptake at similar concentrations. Elevated pyruvate (> 3 mM) resulted in almost complete inhibition of net lactate uptake. Infused [3-13C]lactate or -pyruvate gave rise to labeled glutamate and alanine in vivo, but labeled lactate was not visible when [3-13C]pyruvate was the substrate. The 13C enrichment of myocardial lactate was similar to alanine and acetyl CoA with infused [3-13C]lactate but was only one-half that of alanine and acetyl CoA when [3-13C]-pyruvate was the substrate, indicating a possible inhibition of lactate dehydrogenase.

Dissociation of [H+] from fatigue in human muscle detected by high time resolution 31P-NMR.

Previous in vivo studies of skeletal muscle fatigue have demonstrated significant relationships between the decline of muscular force and changes in muscle metabolism. However, these studies performed measurements over relatively long time intervals or during steady state exercise, thereby obscuring rapid metabolic changes occurring at the onset of exercise and recovery. To overcome these limitations, fatigue of human calf musculature during sustained isometric foot plantar flexion was quantified continuously as the decline in maximal voluntary contraction force (MVC), while concentrations of phosphocreatine (PCr), inorganic phosphate (Pi), intracellular free hydrogen ion (H+), and monovalent phosphate (H2PO4-) were simultaneously measured at 2-second intervals by 31P nuclear magnetic resonance. The first major finding was that [H+], which has been thought to be a mediator of muscle fatigue, actually declined during the first 10 seconds of exercise when force was declining and rose immediately postexercise, when force partially recovered. Second, the correlations of [H+], [H2PO4-] and Pi with MVC during the first minute of exercise were determined to be curvilinear and not linear as previously suggested. Furthermore, using either a linear or curvilinear regression model, [H2PO4-] and Pi demonstrated a closer correlation to MVC than [H+] during the first minute of exercise. Thus, these results reveal nuances in the relationships of MVC to metabolites previously undetected by low time-resolution measurements. These findings suggest that during sustained isometric exercise, rising [H+] is not likely to be the sole mechanism of muscle fatigue and are consistent with the view that a rise of Pi or [H2PO4-] is a major causation factor in force reduction.

Epicardial and endocardial localized 31P magnetic resonance spectroscopy: evidence for metabolic heterogeneity during regional ischemia.

Previous studies have noted that myocardial blood flow and high energy phosphates are heterogeneous across the myocardial wall during ischemia. In order to determine whether differences in metabolites between the subendocardium and subepicardium could be detected using 31P magnetic resonance spectroscopy, the Fourier series window (FSW) experiment was implemented on a porcine model of graded regional ischemia. FSW experiments using a planar phantom showed a 46% improvement in localization to the subendocardium compared to a one-pulse experiment. Animal studies of graded ischemia demonstrated a gradient in the phosphocreatine to inorganic phosphate ratio in the myocardium that paralleled the gradient in blood flow. These studies demonstrate the ability of spatially localized 31P magnetic resonance spectroscopy to detect regional changes in myocardial high energy phosphates localized to the subepicardium and subendocardium.

Response of myocardial metabolites to graded regional ischemia: 31P NMR spectroscopy of porcine myocardium in vivo.

The changes in myocardial high energy phosphates and pH during regional ischemia, and their potential role in mediating functional abnormalities, is unclear. To determine the degree of regional blood flow reduction required to induce changes in high energy phosphates and pH, and to correlate these metabolic changes with alterations in blood flow, 31P nuclear magnetic resonance spectroscopy was employed in an in vivo porcine model of graded coronary stenosis. Simultaneous measurements of regional blood flow and phosphate compounds were made during various steady-state degrees of regional ischemia in which subendocardial blood flow was reduced by as much as 80%. ATP did not fall over the total range of graded ischemia, while phosphocreatine (PCr), inorganic phosphate (Pi), and pH all changed progressively after blood flow was reduced below 50% of normal. The ratio of PCr/Pi (a measure of the energy reserve of the myocardium) was strongly correlated to subendocardial blood flow (r = 0.94) and declined by 25% when blood flow was reduced by only 21% below normal. These findings indicate that PCr/Pi is a sensitive marker of ischemia and support the hypothesis that the in vivo energy status of the myocardium is closely coupled to myocardial blood flow.

Right ventricular contusion: experimental pathophysiology and treatment in an open-chest canine preparation.

To investigate the pathophysiology and treatment of right ventricular (RV) contusion we assessed biventricular function via volume expansion in eight open-chest, anesthetized, ventilated dogs. Measurements were obtained before and after RV contusion with a captive bolt pistol and during dobutamine infusion. RV contusion depressed both RV and left ventricular (LV) performance as assessed by classical ventricular function curves (p less than 0.05). Dobutamine reduced filling pressure (p less than 0.05) and increased cardiac output (CO) (p less than 0.01) when infused post contusion. Because, on inspection, the LV was not contused, the apparent depression in LV function is most likely due to reduced diastolic compliance secondary to ventricular interdependence. In support of this possibility, in four dogs, LV performance significantly improved (p less than 0.05) when the pericardium was opened. We conclude that RV contusion can depress the relationship between CO and filling pressures in both ventricles and that dobutamine is superior to volume in treating the resultant low cardiac output state.