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Biomedical subjects

E Block

Publications and source records attributed to E Block.

At least 19 recordsLinked to original sources
PubMed1992

Effect of recombinant bovine somatotropin on estradiol-induced estrous behavior in ovariectomized heifers.

To evaluate whether bST administration could affect the intensity of estrous behavior in the absence of the ovary, 17 ovariectomized heifers were assigned to receive a placebo or 500 mg/14 d of recombinant bST and were induced to display behavioral estrus by administration of 2 mg of estradiol cypionate. Estrous behavior was monitored for the following 60 h with a surveillance camera and a video recorder, and mounting activity was quantified. Blood samples were collected before and after bST administration. Administration of bST numerically elevated plasma insulin and NEFA and caused a significant increase in concentration of insulin-like growth factor-I in plasma. Heifers that received bST started to display estrous behavior later (24.5 +/- 1.1 and 21.9 +/- 1.1 h after estradiol administration for bST and placebo treatments, respectively), displayed estrous behavior of shorter duration (bST, 13.2 +/- 1.2 vs. placebo, 15.8 +/- 1.1 h), and instigated fewer mounting events (bST, 45.5 +/- 5.9 vs. placebo, 62.6 +/- 5.7 mounts) than control heifers, although only the number of mounting events was significantly different between the two groups.

Animals↗
PubMed1991

Effect of somidobove sustained release administration on the lactation performance of dairy cows.

Lactation performance was determined on 190 multiparous Holsteins from five herds supplemented with 0, 320, 640, or 960 mg of somidobove every 28 d. The experiment consisted of 21 d of pretreatment and treatment periods of various lengths, depending upon stage of lactation of animals at first administration. Somidobove beginning in early (28 to 45 d in milk), mid (111 to 166 d in milk), or late (166 to 334 d in milk) stages of lactation consisted of 9, 6, or 3 administrations. Milk and 3.5% FCM yields were increased by each dose of somidobove in all stages. Milk composition and dry matter and energy intakes were similar among treatments within stage. Milk to DMI ratio and milk energy to net energy intake ratio were improved by somidobove. Gain was positive for all treatments, but less in somidobove-supplemented cows. Lower body weight and condition score at the completion of somidobove treatment resulted. For early cows, days to first estrus and days to first breeding were similar; however, total number of inseminations for cows receiving somidobove was twofold greater than control, resulting in a longer calving interval. Results demonstrated efficacy of somidobove administered every 28 d to lactating dairy cattle for increased milk yield.

Animals↗
PubMed1991

Effects of manipulating dietary cation-anion balance on macromineral balance in sheep.

Effect on macromineral balance in sheep of dietary excess of inorganic anions (Cl and S) or inorganic cations (Na and K) was studied. Dietary cation-anion balance was calculated as milliequivalents [(Na + K) - (Cl + S)] kg-1 of DM. Eight crossbred wethers were fed two levels of Ca, designated high Ca (.82%) or normal Ca (.48%), with four treatment each, three of which differed in dietary cation-anion balance. Control and two treatments had +284, +61, and -27 meq kg-1 of DM for high Ca and +343, +218, and +63 meq kg-1 of DM for normal Ca, respectively. A fourth treatment was control plus injection of vitamin D3 (16,670 IU kg-1 of BW). Reducing dietary cation-anion balance reduced Ca retention by increasing excretion of urinary Ca. Apparent absorption of Ca was similar across cation-anion balances. There was no correlation observed between dietary cation-anion balance and concentration of plasma Ca. No difference was observed in apparent absorption of Ca between high and normal Ca. This result may be related to an oversupply of dietary Ca. Magnesium retention as a proportion of that absorbed for lowest cation-anion balance was smaller than that for the intermediate balance and control plus vitamin D3, although not different from control. Results showed that reduced dietary cation-anion balance resulted in a reduction of Ca retention.

Analysis of Variance↗
PubMed1991

Effects of various dietary cation-anion balances on response to experimentally induced hypocalcemia in sheep.

We examined the effect of dietary cation-anion balance on bone Ca mobilization, measured by challenging wethers with a 5.6% EDTA infusion at a rate of 1.4 ml kg of BW-1. Dietary cation-anion balance was calculated as milliequivalents [(Na + K) - (Cl + S)]. Six crossbred wethers (average BW, 67.8 kg) were fed rations with high Ca (.74% dry basis) or normal Ca (.45%) and three different dietary cation-anion treatments, which differed in their mineral supplementation. Dietary cation-anion balances were 354, 125, and 32 meq kg of DM-1 for control and two treatments. A 6 x 4 incomplete Latin square design (six treatments, four periods) was used with five 15-d periods of 14 d of adaptation followed by 1 d of EDTA infusion. Concentrations of total and EDTA titratable plasma Ca were not affected by the level of dietary Ca or treatments. The decrease in plasma EDTA titratable Ca at conclusion of EDTA infusion (120 min) was least in wethers fed the lowest cation-anion balance within high Ca, and recovery of plasma EDTA titratable Ca during the 240-min postinfusion period was faster for sheep fed this diet than for the control. The amount of Ca mobilized and its rate of mobilization during the EDTA infusion period tended to be higher for diets with reduced cation-anion balances than for the control. Thus, reducing cation-anion balance increased the sheep's ability to mobilize Ca during hypocalcemia.

Acute Disease↗
PubMed1991

Effects of reducing dietary cation-anion balance on calcium kinetics in sheep.

A Ca kinetic study with a four-compartment model being fitted to radioisotope and balance data using the CONSAM (conversational, simulation, analysis, and modeling) computer program was conducted to examine the effects of dietary cation-anion balance, calculated as milliequivalents [(Na + K] - (Cl + S)]. Twelve crossbred wethers were used as eucalcemic control (period 1); then Ca loss during lactation was simulated by continuous infusion of ethylene glycol tetraacetate (period 2). Dietary cation-anion balance was manipulated by supplementation of various mineral salts and was +339, +35, and -127 meq of kg DM-1 during period 1 and +429, +68, and -147 meq of kg DM-1 during period 2 for control and two treatments, respectively. Animals responded to the simulated lactational Ca loss (period 2) by increasing true intestinal absorption of Ca and bone resorption and by reducing Ca accretion by bone. No difference was observed in concentration of total Ca in plasma, but treatments produced increased concentration of plasma ionized Ca during both periods. Both treatments produced hypercalciuria during both periods, and the lowest cation-anion balance increased true intestinal absorption of Ca and reduced bone accretion during period 2. The size of total exchangeable Ca pool did not differ between treatments or periods, but amount of Ca movement between the pools increased with the intermediate cation-anion balance during period 1 and with both treatments during period 2 compared with control. These results indicated that feeding reduced cation-anion balance diets increased Ca flux through the exchangeable Ca pool with no changes in the size of the pool, particularly when Ca demand was increased.

Animal Feed↗
PubMed1990

1-Butyryl-glycerol: a novel angiogenesis factor secreted by differentiating adipocytes.

Differentiation of adipocytes is accompanied by secretion of molecules stimulating angiogenesis in vivo and endothelial cell growth and motility in vitro. We demonstrate that the angiogenic and motility-stimulating activities secreted by adipocytes are separable from the endothelial cell mitogenic activity by fractionation of adipocyte-conditioned medium. The major differentiation-dependent angiogenic molecule was purified and identified by GCMS as 1-butyryl-glycerol (monobutyrin). Monobutyrin levels increase at least 200-fold during adipocyte differentiation and represent a major fraction of the total angiogenic activity. Synthetic monobutyrin shows the same spectrum of biological activities as the adipocyte-derived factor: stimulation of angiogenesis in vivo and microvascular endothelial cell motility in vitro, with no effect on endothelial cell proliferation. Angiogenesis is stimulated at doses as low as 20 pg when tested in the chick chorioallantoic membrane assay. These results strongly suggest that monobutyrin is a key regulatory molecule in an angiogenic process linked to normal cellular and tissue development.

Adipose Tissue↗
PubMed1990

Effect of somatotropin on the plasminogen and plasmin system in the mammary gland: proposed mechanism of action for somatotropin on the mammary gland.

Somatotropin exerts a powerful galactopoietic effect when it is administered to dairy cattle. The mechanism by which somatotropin increases milk yield is currently unknown. This study describes the relationship between long-term exogenous somatotropin injections, milk plasmin concentrations, and milk yield. Plasmin is a serine-protease involved in rodent mammary gland involution. Thirty-five control cows were shown to increase milk plasmin concentrations and decrease milk yield as their lactation period advanced past the 2nd mo. In 42 somatotropin injected cows, milk plasmin was maintained at low concentrations, and milking performance was enhanced. Cessation of somatotropin injections at drying off led to a rapid elevation of milk plasmin to control values. Our hypothesis is that somatotropin suppresses plasmin production within the mammary gland, thereby suppressing involution and allowing a persistence of milk production. During a normal lactation, gradually increasing amounts of plasmin within the mammary gland results in the gradual involution process.

Animals↗
PubMed1990

Effects of recombinant bovine somatotropin on nutritional status of dairy cows during pregnancy and of their calves.

Objectives of this trial were to evaluate effects of rbST on the nutritional status of 24 Holstein cows during pregnancy and of their calves from birth to weaning. All cows conceived during injection with either a placebo or 350 mg of rbST in a sustained-release vehicle every 14 d commencing 98 to 112 d postpartum for their entire lactation. In Experiment 1, blood samples were collected at 90, 180, and 270 d postconception in cows. Concentrations of urea, glucose, albumin, total proteins, Ca, P, insulin, cortisol, hemoglobin, and hematocrit were unaffected by treatment as well as BW, body condition scores, and energy balances at conception and during pregnancy. Days open and calving interval were not significantly different but were numerically increased by 31 d in rbST-injected cows. Nonesterified fatty acids, bST, and insulin-like growth factor-I in plasma were elevated significantly in rbST-injected cows. In Experiment 2, blood samples were collected at birth and at 1, 3, 5, and 7 wk in calves born from cows of Experiment 1. Circulating concentrations of glucose, nonesterified fatty acids, albumin, total proteins, hemoglobin, insulin, cortisol, bST, insulin-like growth factor-I, and hematocrit, blood pH, blood gases and buffer capacity, birth weight and rate of weight gain, height at withers, and heart girth from birth to weaning were not different due to treatment of dam. However, some parameters were significantly different based on age and sex. These data support previous assumptions that the magnitude of the modifications in nutrient partitioning produced by rbST do not affect the hierarchy of the partitioning process for the calf.

Animals↗
PubMed1990

Effects of recombinant bovine somatotropin on nutritional status and liver function of lactating dairy cows.

Twenty-four high producing, multiparous Holstein cows were utilized to evaluate effects of long-term administration of sustained-release rbST on blood pH, gases, buffer capacity, circulating metabolites and hormones, and on liver lipid content and functions during lactation. Treatment, commencing 98 to 112 d postpartum and continued until d 305, consisted of a subcutaneous injection of a placebo or 350 mg of rbST every 14 d. Milk and 3.5% FCM were increased significantly by rbST, but milk fat and protein content, feed intake, energy balance, corrected feed efficiency for milk production, and body condition scores were unaffected. Somatotropin decreased blood pH and buffer capacity by decreasing bicarbonate without affecting blood partial pressures of oxygen or carbon dioxide. Concentration of plasma albumin was decreased and nonesterified fatty acids, glucose, insulin, rbST and insulin-like growth factor-I were increased by treatment. Total plasma proteins and cortisol, hemoglobin, and hematocrit were unaffected. Liver DM, total lipid and triacylglycerol contents, and plasma 3-hydroxybutyrate and glutamic oxalacetic transaminase were not affected by rbST, but the percentage of triacylglycerol in total lipids was increased. Results of this experiment suggest that rbST exhibited lipolytic and diabetogenic activities in lactating dairy cows in vivo and that these effects might be important for the increase in nutrient partitioning toward the mammary gland elicited by rbST.

Animals↗
PubMed1990

Influence of exercise on a heart transplant patient.

A treadmill training protocol was implemented to examine the effects of a 12-week exercise program on the physiologic status of a patient who had a heart transplant in 1980. The patient was tested for exercise tolerance before programming, midway through the study, and immediately upon completing endurance training. Maximal METS levels achieved were 3.2 METS, 5.6 METS, and 6.3 METS, respectively. The subject began an anaerobic program consisting of 48 exercise sessions over a three-month period. Exercise sessions were interval in nature, walking at 2.5 mph, 0% grade, three repetitions, five minutes each and increasing to 3.0 mph, 2.5% grade, two repetitions, 15 minutes each. The patient improved from Class III (METS = 3.0), where less than ordinary physical activity causes fatigue, to Class I (METS = 6.5), where ordinary physical activity can be sustained without undue fatigue. These findings suggest that selected heart transplant patients may achieve up to 85% maximum oxygen consumption and maximum heart rate which demonstrates the need for endurance training programs in this population. This form of cardiovascular conditioning has enabled the participant to engage in higher levels of activities of daily living within the community.

Blood Pressure↗
PubMed1989

Inhibition of soybean lipoxygenase and mouse skin tumor promotion by onion and garlic components.

Onion and garlic essential oils were previously shown to inhibit mouse skin tumor promotion, as were the enzymes, lipoxygenase, and cyclooxygenase. In the present study, the inhibition of soybean lipoxygenase (EC 1.13.11.12) by onion and garlic components and related compounds was investigated. The IC50 values as well as the kinetic inhibition constants were determined for the most active compounds. Di-(1-propenyl) sulfide, an analog of the substrate moiety required for oxygenase action, was the only irreversible inhibitor observed with Ki = 59 microM and k3 = 0.53/min. Inhibition in the presence of substrate was uncompetitive at 88 and 132 microM linoleic acid with Ki = 129 microM. At 173 microM linoleic acid, however, inhibition was competitive with Ki = 66 microM. Dially trisulfide, allyl methyl trisulfide, and diallyl disulfide were competitive inhibitors, while 1-propenylpropyl sulfide and (E, Z)-4,5,9-trithiadodeca-1,6,11-triene 9-oxide (ajoene) were mixed inhibitors. Nordihydroguaiaretic acid (NDGA), the most potent lipoxygenase inhibitor, was a competitive inhibitor with Ki = 0.29 microM. The results indicate a relative potency of inhibition for structural features in the following order: di(1-propenyl) sulfide greater than an alkenyl trisulfide greater than an alkenyl disulfide. Di(n-propyl) disulfide, a major onion oil component, inhibited neither lipoxygenase nor promotion. Di(1-propenyl) sulfide and ajoene inhibited both. This suggests that the inhibition of lipoxygenase may be involved in antipromotion.

Allium↗
PubMed1989

Sodium chloride supplementation and urinary calcium excretion in postmenopausal women.

It was hypothesized that variations within the range of usual salt intakes of North Americans influence urinary excretion of calcium in healthy postmenopausal women. The effects of sodium chloride supplements of 0.51, and 102 mmol/d, randomly assigned to 17 healthy, noninstitutionalized, postmenopausal women consuming their usual diets were compared. Diets and discretionary salt intake were repeated exactly for three experimental periods of 4 d each for 3 consecutive weeks. Supplementing with 51 mmol NaCl/d increased average daily urinary excretion of Ca, Na, and Cl by 0.5, 51.0, and 48.9 mmol respectively, urine pH by 0.1, and serum Cl by 1.5 mmol/L (p less than 0.05). Supplementing with 102 mmol/d induced additional increases in these variables (p less than 0.05). Assuming a total body mass of 900 g Ca and no decrease in renal or fecal losses, additions of 51 and 102 mmol/d NaCl to the diet for 10 y would mobilize Ca stores of 7.5% and 10%, respectively, and could thus constitute a risk factor for osteoporosis.

Age Factors↗
PubMed1989

Plasmin and plasminogen in bovine milk: a relationship with involution?

A total of 774 individual milk samples were collected from 66 Holstein cows between October 1987 and April 1988. Samples were analyzed for plasmin, plasminogen, and SCC. An increase in SCC from less than 250,000/ml to more than 1,000,000/ml resulted in an increase of plasmin, plasminogen, and serum albumin by 105, 74, and 140%, respectively. Plasminogen, plasmin, and serum albumin followed similar trends that are expected for components from blood that gain access to the alveolar lumen through ruptured epithelium caused by mastitis. Increased plasmin is the direct result of this process rather than an increase in activation of plasminogen to plasmin. The plasminogen to plasmin ratio supports this interpretation, being 4.7 at 250,000 SCC/ml and 4.0 when SCC exceeded 1 million/ml. Plasmin and plasminogen concentrations were also increased during lactation to reach peak values immediately before the dry period. However, in this case, ratio of plasminogen to plasmin was 6.55 during early lactation and decreased by half to 3.29 during the latest stage, indicating that considerable activation of plasminogen to plasmin occurred during the latter part of lactation. Mammary epithelium is not compromised at this stage, as shown by low (.8 mg/ml) serum albumin concentration in milk. Two mechanisms responsible for increased milk plasmin include influx of plasmin from blood during mastitis and increased activation of plasminogen as lactation progresses.

Animals↗
PubMed1987

Efficacy of Levamisol on milk production of dairy cows: a field study.

Twelve hundred ninety-six cows on 88 farms were alternately injected at calving with Levamisol or saline. Each farm was visited every 2nd wk from May to October to administer treatments to cows that would calve prior to our next visit and to collect fecal grab samples from cows for worm egg counts. Production records were collected for each cow for their first 6 mo of lactation. Fecal worm egg counts were reduced in cows treated with Levamisol for the first 2 mo postcalving. Daily milk produced was higher in cows treated with Levamisol by 1.24 kg. Milk fat and protein percentages were not different between treatment groups; however, milk fat production was higher in cows treated with Levamisol for the first 2 mo post-calving. Cows treated with Levamisol produced 235 kg more milk than control cows during their first 6 mo of lactation and were projected to produce 339 kg more milk for a 305-d lactation. Month of calving improved milk production by cows treated with Levamisol. Cows treated with Levamisol and calved in months May to July showed the highest improvement in milk production while cows that were treated with Levamisol and calved in months August to October showed no significant improvement in production. Injection of cows with Levamisol at calving improves milk production and reduces gastrointestinal worm burdens.

Animals↗
PubMed1987

Ergometer modification for combined arm-leg use by lower extremity amputees in cardiovascular testing and training.

A commercial arm-leg ergometer was adapted so that combined bilateral arm-single leg work could be performed by unilateral lower extremity amputees from their own wheelchairs. Three middle-aged to elderly unilateral amputees performed progressive discontinuous bilateral arm crank and combined bilateral arm-single leg cycle exercise tests on the same air-braked ergometer adapted for either form of ergometry. Select amputees may achieve greater peak oxygen uptakes (VO2), power outputs (PO), and heart rates (HR) during combined bilateral arm-single leg cycle testing versus bilateral arm crank testing. Following 14 weeks of combined arm-leg training on the modified ergometer, a 73-year-old above-knee amputee demonstrated peak VO2 and PO increases of 25% (+3.8 mL X kg-1 X min-1) and 33% (+25W) respectively. Combined arm-leg ergometry as described herein may activate the largest available muscle mass and elicit the greatest oxygen uptake during exercise testing. In addition this exercise modality may simultaneously condition the arms and leg, providing functional gains in both wheelchair propulsion and prosthetic ambulation.

Amputees↗
PubMed1986

Efficacy of morantel tartrate on milk production of dairy cows: a field study.

Eighty Holstein herds on Quebec Dairy Herd Analysis Service were paired into 40 blocks of two herds each to test the effects of systematic deworming with morantel tartrate. Cows in treated herds were given morantel tartrate in May, June, and July, and cows in control herds were given a placebo of ground corn, wheat bran, and barley; both products were administered at 1 kg/1000 kg body weight. Records were obtained from May 1983 to April 1984. Each farm was visited monthly from May to October 1983 to obtain herbage samples and fecal grab samples from a random 10% of lactating cows. Production records were obtained for the year prior to commencement of this trial for covariate analysis. Fecal worm egg counts and infective larvae counts in pasture were reduced by 83 and 93%, respectively, in treated herds. The pattern of worm egg excretion differed between groups due to repeated treatments with morantel. Treated herds produced 323 kg more milk per cow per yr and 1.2 kg per cow per d more fat-corrected milk than controls. Milk fat and protein percentages did not differ between groups for the 12 mo. Deworming lactating dairy cows at the beginning of and during the pasture season improved production performance.

Animals↗