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Biomedical subjects

E Block

Publications and source records attributed to E Block.

At least 55 records · Page 3Linked to original sources
PubMed1994

Effect of plane of nutrition before and during gestation on the concentration of hormones in dairy heifers.

Forty heifers (1 yr of age; 313 +/- 27 kg of BW) were assigned to one of four treatments in a 2 x 2 factorial design. Main effects were plane of nutrition (ad libitum vs. moderate feeding) during the second isometric phase (1 yr of age to 3 mo of gestation) and during the second allometric phase (3 mo of gestation to 14 d before calving) of mammary development. Jugular blood samples were collected from 16 heifers before the onset of treatment, at the end of the isometric phase, and at the end of the allometric phase. Additional daily blood samples were collected from 32 heifers from 14 d before expected calving to 10 d postpartum and then thrice weekly until 70 d postpartum. High plane of nutrition reduced average growth hormone concentrations during the isometric and allometric phases. Serum concentrations of prolactin tended to be higher in heifers on ad libitum intake during the isometric phase and were higher during the allometric phase. Prolactin was positively correlated with BW and average daily gain during allometric phase. Plasma IGF-I concentrations were not affected by plane of nutrition. No effect was found for previous plane of nutrition on concentrations of growth hormone, prolactin, IGF-I, and progesterone during either prepartum or postpartum periods. Average postpartum IGF-I concentrations were negatively correlated with milk production. A positive relationship existed between mean postpartum concentrations of growth hormone and both peak milk production and feed intake during lactation.

Animal Nutritional Physiological Phenomena↗
PubMed1994

Manipulation of dietary cation-anion difference on nutritionally related production diseases, productivity, and metabolic responses of dairy cows.

Dietary cation-anion difference has been defined as milliequivalents of (Na+K)-(Cl+S) per kilogram of DM and has a direct impact on blood acid-base metabolism. As this difference decreases, one or more of the following blood parameters change: increased H+, decreased HCO3-, and decreased pH. These changes are accompanied by reduced urinary HCO3- excretion and pH as compensatory mechanisms. Although other minerals have an impact on acid-base metabolism, the four minerals used in dietary cation-anion difference have the greatest effect. Manipulation of acid-base balance can be used to manipulate other biological functions to benefit health and productivity of cows. Low cation-anion difference prepartum can mitigate hypocalcemia peripartum via increased urinary Ca, blood-ionized Ca, and responsiveness to Ca homeostatic hormones. These changes reduced the incidence of paresis and increased productivity by reducing the severity and length of hypocalcemia in all cows (periparturient), regardless of the occurrence of paresis. Reduced cation-anion differences prepartum have been related to a reduced severity of udder edema, likely related to increased renal loss of water and unchanged water intake. However, the effects on acid-base balance cannot be ruled out because of effects on biochemical and transport processes. Elevated cation-anion difference in lactation has been shown to increase DMI and production and to mitigate the effects of heat stress. Because production and heat stress are acidogenic, elevated cation-anion difference improves blood-buffering capacity to cope with H+. In heat stress, elevated water intake with elevated cation-anion difference cannot be ignored. Other diseases related to metabolic acid, such as laminitis and ketoacidosis, may be influenced by elevated cation-anion difference in lactation; however, research in these areas has not been forthcoming.

Acid-Base Equilibrium↗
PubMed1993

Effect of plane of nutrition of dairy heifers before and during gestation on milk production, reproduction, and health.

Fifty-nine heifers (1 yr of age; 320 +/- 12 kg) were assigned to one of four treatments of a 2 x 2 factorial design. Main effects were plane of nutrition (ad libitum vs. moderate feeding) during the second isometric phase (1 yr of age to 3 mo of gestation) and during the second allometric phase (3 mo of gestation to 14 d before calving) of mammary development. During the isometric phase, average daily gain were .72 and .84 kg/d for heifers fed a moderate or ad libitum diet, respectively. During the allometric phase, average daily gain was affected by previous plane of nutrition and averaged .84, .66, .95, and .73 for continuous ad libitum, ad libitum followed by moderate, moderate followed by ad libitum, and continuous moderate feeding, respectively. The BW at the end of gestation and BW after calving were increased by ad libitum feeding during the allometric phase (643 vs. 605; 588 vs. 558 kg, respectively). Milk production, protein content, and withers height were not affected by plane of nutrition. Milk fat was increased by ad libitum feeding during the isometric phase (3.9 vs. 3.6%). Cows on ad libitum feeding during the allometric phase had reduced average daily gain during lactation (.02 vs. .15 kg/d). The resumption of ovarian activity (progesterone > 1 ng/ml) was not affected by treatment, but days to first observed estrus increased with ad libitum feeding during the allometric phase. Finally, ad libitum feeding during isometric phase resulted in a higher incidence of displaced abomasum after calving, 9 versus 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Nutritional Physiological Phenomena↗
PubMed1993

Pneumocystis carinii pneumonia in patients with ulcerative colitis treated with corticosteroids.

Today, Pneumocystis carinii pneumonia (PCP) is typically associated with AIDS. However, in the pre-AIDS era, PCP was known to be associated with various immunodeficiency states, malignancies, and immunosuppressive therapy, particularly the use of corticosteroids. PCP has been reported to occur during immuno-suppressive therapy of some chronic inflammatory states, but it has never been reported in patients with inflammatory bowel disease. We report two patients with ulcerative colitis who developed PCP during high-dose corticosteroid therapy, and review the literature regarding non-AIDS PCP. PCP should thus be added to the list of bronchopulmonary complications in inflammatory bowel disease. This report should give gastroenterologists further impetus to limit immunosuppressive therapy to its minimal effective dose.

Adult↗
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↗