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Biomedical subjects

R D Miles

Publications and source records attributed to R D Miles.

At least 55 records · Page 3Linked to original sources
PubMed1987

Effect of antibiotics on tissue trace mineral concentration and intestinal tract weight of broiler chicks.

Two experiments were conducted with broiler-type chicks to determine the effect of antibiotics on intestinal weight and kidney, bone, and liver trace mineral concentrations. All antibiotics were in diets at the manufacturers' recommendations. Feed intake of experimental diets (antibiotics or non-treated control) was restricted to 90% of that of an additional group fed the control diet ad libitum. Feed intake, weight gain, and feed efficiency were not affected (P greater than .10) by dietary treatments. Virginiamycin decreased intestinal weight an average of 19% as compared with 14% for bambermycins and oxytetracycline, 6% for Zn bacitracin, and 18% for lincomycin. Except for Zn bacitracin, all antibiotics produced intestinal weights which were lower (P less than .01) than those of controls. Only virginiamycin increased (P less than .01) kidney Mn concentration. Bone Mn concentration was greater (P less than .01) for virginiamycin than bambermycins or oxytetracycline in Experiment 2, and greater (P less than .05) for lincomycin than virginiamycin or Zn bacitracin in Experiment 2. Feeding Zn bacitracin increased (P less than .01) bone Zn concentration whereas feeding virginiamycin caused a decline (P less than .05) in bone Zn concentration in Experiment 1. There were no differences in Cu, Zn, or Fe concentrations in liver or kidney.

Animals↗
PubMed1987

Effect of dietary fructose on broiler chick performance.

The effect of feeding various levels of dietary fructose, furnished by high fructose corn syrup (HFCS), to broiler-type chicks housed in Petersime batteries was studied in two experiments. In experiment 1, HFCS was added to a corn-soybean meal basal diet at levels of 0, 5, 10, and 15%. In Experiment 2, HFCS was added to the diet at levels of 0, 2, 4, 6, and 15%. In both experiments diets were isocaloric and isonitrogenous. In Experiment 1, chicks fed HFCS consumed more feed (P less than or equal to .05) and grew more rapidly (P less than or equal to .05) than chicks fed the control diet. No differences in the feed to gain ratio were observed among treatments. Feeding HFCS resulted in non-significantly higher liver weight and percent liver lipid. Values for kidney weights and plasma uric acid were higher (P less than or equal to .05) in chicks fed 15% HFCS. In Experiment 2, adding 4, 6, and 15% HFCS resulted in more rapid growth (P less than or equal to .05). No significant differences were observed in feed intake and kidney weights. Chicks fed the 15% HFCS diet had heavier (P less than or equal to .05) livers.

Animal Nutritional Physiological Phenomena↗
PubMed1987

Interaction of dietary nutrient concentration and supplemental copper on chick performance and tissue copper concentrations.

An experiment was conducted with 576 female Cobb feather-sexed chicks to study the influence of methionine (MET) and selected nutrient (SN) supplementation on the performance of chicks fed high Cu levels. Day-old chicks were allotted randomly to pens for the 22-day experiment. A 3 X 2 X 2 factorial arrangement of treatments was used which included Cu at 0, 400, and 800 mg/kg, MET at 0 and .4%, and SN at 0 and 20%. A significant (P less than .001) Cu X MET X SN interaction was found for gain. Supplemental MET reversed the growth depression observed in birds fed 400 but not 800 mg/kg Cu. Additions of 400 and 800 mg/kg Cu to the basal diet depressed (P less than .001) feed consumption by 8.6 and 19.4%, respectively. Hepatic Cu concentrations increased linearly (P less than .001) with increasing dietary Cu and were not influenced (P greater than .10) by supplemental MET or SN. Liver weights increased linearly (P less than .001) with increasing dietary Cu and were higher (P less than .05) for chicks on diets supplemented with SN, but lower (P less than .05) for those with diets supplemented with MET. The interaction of MET X SN was significant (P less than .001) for serum Cu; chicks supplemented with SN in conjunction with MET had the lowest (P less than .05) serum Cu concentrations. Serum glutamic-oxaloacetic transaminase (SGOT) activity was not influenced (P greater than .10) by dietary Cu, but SN supplementation resulted in a 10% elevation (P less than .001) in SGOT activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Relationships of five Doppler measures with flow in an in vitro model and clinical findings in newborn infants.

This report compares six Doppler ultrasound measures of blood flow: Pourcelot's pulsatility index, Gosling's pulsatility index, area under the curve, systolic amplitude, diastolic amplitude, and mean amplitude. Recordings from an in vitro arterial model and from the anterior cerebral arteries in 33 newborn infants with asphyxia, intraventricular hemorrhage, or normal state were analyzed. In the model, all measures had excellent correlation with flow. Neonates were correctly classified according to diagnosis by the Doppler measures as follows: Pourcelot's pulsatility index (100%), Gosling's pulsatility index (97%), diastolic amplitude (94%), mean amplitude (76%), area under the curve (70%), and systolic amplitude (58%). The best accuracy was obtained with the pulsatility indices.

Asphyxia Neonatorum↗
PubMed1986

Relative accuracy of the diagnostic components of noninvasive carotid arterial tests: a comparison of pulsed Doppler arteriography and spectrum analysis.

Pulsed Doppler ultrasonography (UA), sound spectrum analysis, and subjective interpretation of the audible signal are valuable methods for assessing carotid arterial disease; however, the relative contribution of each in making a diagnosis is disputed. To investigate this issue, 258 noninvasive carotid studies with measured x-ray comparisons were reviewed. Internal carotid spectra, UA images, and images combined with the technician's comments were each interpreted blindly by three independent readers. Percentage of stenosis was categorized into six groups: 0, 1% to 24%, 25% to 49%, 50% to 74%, 75% to 99%, and 100%. Each reader's assessment of the individual noninvasive components and his overall reading of the complete study were compared with x-ray findings and with those of the other two readers. The readings of the three observers were consistent within each diagnostic component (p less than 0.001). For each reader, the technician's comments significantly improved the accuracy of ultrasonic imaging alone (p less than 0.001). Spectrum analysis was as good as the image plus technician's comments and, for two of three readers, was better than the image alone (p less than 0.001).

Angiography↗
PubMed1986

Physiology of the peaked finger pulse in normal and cold-sensitive subjects.

A unique peaked digital pulse contour (DPC) is frequently observed in patients with cold sensitivity, but the pathophysiology of this pulse remains obscure. To investigate the responses of the DPC to cold exposure, finger blood pressure (FBP), finger blood flow (FBF), and finger skin temperature (FST) were measured in fingers of both hands of 13 normal subjects and in 16 patients with cold sensitivity. The ratio, FBP/FBF, was used to estimate small vessel resistance (SVR). One hand was immersed sequentially in water at 40 degrees, 30 degrees, 20 degrees, and 10 degrees C, while the other hand remained in room air. DPCs were classified as normal (N), intermediate (I), intermediate-peaked (IP), peaked (P), obstructive (O), and spastic obstructive (SO). At room temperature, fingers with I, IP, O, and SO pulses had increased SVRs and decreased FSTs, and those with O and SO had decreased FBP. On cold exposure IP pulses appeared in both hands of both normal and cold-sensitive subjects, but P pulses developed only on the cooled side. IP and P pulses were associated with an increase in SVR. We concluded that IP pulses are related to reflex sympathetic arteriolar vasoconstriction, that P pulses imply vasoconstriction produced directly by cold exposure, and that O, SO, or absent pulses are indicative of digital arterial vasospasm.

Adolescent↗
PubMed1986

Changes in blood flow and metabolism in a neurovascular island skin flap after a burn.

In 8 male white Yorkshire pigs weighing approximately 42 kg each, 12 buttock neurovascular island skin flaps were dissected. Baseline recordings were made of blood flow and O2 consumption in the flap. Two series of experiments were carried out. In control animals (5), the flap was dissected and the "cold" aluminum plate was applied for 10 seconds. In the burned flaps (7) a contact burn of 2.68 calories/cm2 was created with a heated aluminium plate applied to the skin for 10 seconds. After this the flaps were studied for 4 hours. In the control flaps, blood flow and O2 consumption did not change. The burned flaps showed no change in blood flow, while O2 consumption increased significantly from .07 +/- .01 (SE) ml/100 g/min to .18 +/- .08 (SE) ml/100 g/min (p less than .05).

Animals↗
PubMed1986

Methionine, choline and sulfate interrelationships in the diet of weanling swine.

Experiments were conducted to examine the interrelationships between methionine, choline and inorganic sulfate in the diet of weanling pigs, and to evaluate the selenium (Se) status of pigs fed diets with or without supplemental sulfate. Two trials utilized 288 weanling (3-wk-old) pigs allotted to dietary treatment based on weight, sex and litter origin. There were six pigs/pen and three replicate pens/treatment in each trial. The basal corn-soybean meal diet was formulated to supply .55% sulfur amino acids and contained a choline and sulfur-free vitamin and mineral premix. Lysine was added to provide a total of 1.13% lysine. Seven additional treatments were formulated by substituting for corn .17% DL-methionine, .29% choline dihydrogen citrate or .25% Na2SO4 to create a 2(3) factorial arrangement of treatments. There were methionine X choline X sulfate interactions for average daily gain (P less than .001) and feed-to-gain ratio (F:G; P less than .05). Adding choline, methionine, Na2SO4 or choline plus methionine to the basal diet did not improve gains. However, when Na2SO4 plus methionine or Na2SO4 plus choline were added, daily gains were increased (P less than .05) and F:G was improved (P less than .1). Addition of all three supplements did not result in a further increase in gain. Pigs fed choline-supplemented diets had higher (P less than .01) hematocrit and tended (P = .07) to have increased hemoglobin concentration. There was no effect on serum triglycerides or alkaline phosphatase activity due to dietary treatment. The concentration of Se in muscle, liver, kidney and blood was not influenced by sulfate content of the diet.

Animals↗
PubMed1986

Influence of virginiamycin and dietary manganese on performance, manganese utilization, and intestinal tract weight of broilers.

An experiment was conducted with day-old Cobb feather-sexed chicks for 21 days to study the effect of virginiamycin and dietary manganese on tissue uptake of manganese and intestinal tract weight. The 2 X 2 factorial arrangement of dietary treatments included 0 or 12 ppm virginiamycin and 0 or 1000 ppm added manganese as MnSO4 X H2O. Ad libitum intake was determined with four pens of five birds fed the basal corn-soybean meal diet. To eliminate the possibility that tissue manganese concentration of virginiamycin-fed birds could be attributed to increased dietary manganese intake, chicks fed experimental diets were restricted to 90% of the previous day's intake of ad libitum-fed birds. Feed intake, average daily gain, and feed efficiency were not affected by treatments. Virginiamycin decreased (P less than .001) relative intestinal tract weight from 3.34 to 2.68 g/100 g body weight. Kidney and bone manganese increased (P less than .05) when virginiamycin was fed (14.0 vs. 15.4 ppm dry basis and 21.8 vs. 24.6 ppm ash basis, respectively), indicating that virginiamycin increased absorption of manganese.

Animals↗
PubMed1986

Bioavailability of manganese sulfate and manganese monoxide in chicks as measured by tissue uptake of manganese from conventional dietary levels.

The biological availability of reagent grade manganese sulfate and manganese monoxide was determined in broiler chicks fed conventional dietary Mn levels. A basal corn-soybean meal diet (35 ppm Mn) was supplemented with 40, 80, or 120 ppm Mn from the two sources and fed ad libitum for 21 days. There were no differences in average daily feed intake, daily gain, or feed conversion among treatments. There was a linear (P less than .001) increase in bone, kidney, and liver Mn as dietary Mn increased. Manganese monoxide averaged 66% of the availability of manganese sulfate as determined by a combination of linear regression, multiple linear regression and tissue Mn increase. Bioavailability was similar to that obtained when sources were fed at high dietary levels in a previous study.

Animals↗
PubMed1986

Response of laying hens to choline when fed practical diets devoid of supplemental sulfur amino acids.

Two experiments were conducted with White Leghorn laying hens. In both experiments, a corn-soybean meal basal diet was used, and hens were housed individually in cages in open-type houses. In Experiment 1, the basal diet contained no supplemental choline, inorganic sulfate, or sulfur amino acids and was supplemented with 0 or 660 mg choline/kg, and 0 and .1% K2SO4, or K2Mg(SO4)2. In Experiment 2, the basal diet contained .1% reagent grade K2SO4. Four diets were formulated to contain 0, 110, 220, and 440 mg choline/kg, respectively. A fifth diet was formulated to contain 440 mg choline/kg and .15% DL-methionine. In Experiment 1, a significant increase in egg production resulted from supplementing the diet with 660 mg choline/kg in the absence of supplemental inorganic sulfate and sulfur amino acids. Only a numerical increase in egg production resulted from adding inorganic sulfate alone or in combination with choline. Addition of choline and inorganic sulfate in combination resulted in an increase in egg weight. In Experiment 2, 220 mg of supplemental choline/kg, or 114 mg choline intake/bird/day, resulted in maximum egg production and feed efficiency. However, maximum egg size was obtained only when supplemental DL-methionine and choline were present. The results obtained in this study indicate that laying hens will respond to supplemental choline in practical situations when diets are deficient in total sulfur amino acids, and daily sulfur amino acid intake is insufficient to meet the animal's requirement. For maximum egg size, adequate sulfur amino acids must be present in the diet, because supplementing choline alone will not maximize egg size.

Amino Acids, Sulfur↗
PubMed1986

Influence of virginiamycin on broilers fed four levels of energy.

An experiment was conducted with broiler chicks to determine the influence of Virginiamycin on chicks fed diets with four levels of energy. Addition of the Virginiamycin to the diet resulted in significantly improved body weight and feed efficiency at all levels of energy. The greatest improvement was obtained at the lowest level of energy. Addition of Virginiamycin to the diet decreased the energy required to produce a unit of body weight.

Animals↗
PubMed1986

A differential response in turkey poults to various antibiotics in diets designed to be deficient or adequate in certain essential nutrients.

Two experiments, each consisting of two trials, were conducted with day-old Nicholas Large White turkey poults to compare the effectiveness of four antibiotics for growth promotion and the utilization of sulfur amino acids. A corn-soybean meal basal diet that contained no supplemental methionine, choline, or inorganic sulfate was used in order to furnish nutritional stress. The diet was calculated to contain 25.4% protein, .448% methionine, .403% cystine, 1014 mg/kg choline, and 2990 kcal metabolizable energy/kg. In Experiment 1, a 2 X 4 factorial arrangement of treatments was used. This included two levels, (0% (control) and .18%), of supplemental DL-methionine and no antibiotic or bacitracin MD, flavomycin, or virginiamycin; antibiotics were fed at 50, 2, and 20 g/ton, respectively. In Experiment 2, lincomycin also was included as a treatment (at 4 g per ton) resulting in a 2 X 5 factorial arrangement of treatments. Only the addition of Virginiamycin to the control diet in Experiment 1 resulted in significantly increased body weights. Supplementation by .18% methionine increased body weights and feed efficiency. In addition, all three antibiotics increased body weights significantly when added to the .18% methionine diets. Feed efficiency values were improved by all four antibiotics at both methionine levels. In Experiment 2, increases in body weights similar to those in Experiment 1 were obtained with the addition of .18% methionine to the basal diets. Addition of lincomycin and virginiamycin improved body weights and feed efficiencies in the presence and absence of supplemental methionine.

Animals↗
PubMed1985

Noninvasive assessment of stroke risk in asymptomatic and nonhemispheric patients with suspected carotid disease. Five-year follow-up of 294 unoperated and 81 operated patients.

Based on the assumption that greater than or equal to 50% stenosis of the internal carotid artery increases stroke risk, noninvasive tests are being used to screen patients for prophylactic carotid endarterectomy. To assess the validity of this concept, 104 asymptomatic and 190 nonhemispheric patients referred for cerebrovascular tests were reviewed after 5 years. Carotid stenosis greater than or equal to 50% predicted a 15% stroke incidence at 2 years compared to a 3% incidence with 1-49% stenosis (p less than or equal to 0.05). Five-year cumulative stroke incidence was 21% with greater than 50% stenosis, 14% with 1-49% stenosis (NS), and 9% with 0% stenosis (p less than 0.05). Stenosis greater than or equal to 50% predicted increased cardiac mortality (p less than 0.025). Hypertensive patients, greater than 70 years, with greater than or equal to 50% stenosis had a 37% incidence of stroke; normotensive patients, less than 70 years, with or without stenosis, had few strokes. In patients with greater than or equal to 50% disease, surgery reduced the 5-year stroke rate from 21 to 8% (p less than 0.05), mitigated the effects of age and hypertension, and improved survival. Noninvasive test results must be considered in conjunction with age and hypertension in predicting stroke risk.

Actuarial Analysis↗
PubMed1985

Virginiamycin and laying hen performance.

Two experiments were conducted for five 28-day periods each. In Experiments 1 and 2, Hyline W-36 hens, 36 and 26 weeks of age, respectively, were used. Experiment 1 was designed to measure the effect of virginiamycin on hen performance and egg characteristics when supplementing a diet having low pigmentation potential. In Experiment 2, the diet contained 3% added fat with 0, 10, and 20 ppm virginiamycin. In Experiment 1, virginiamycin-supplemented hens showed increased (P less than or equal to .05) egg production, body weight, and improved feed efficiency. When egg production and feed efficiency were ranked by quartiles within the control and virginiamycin-supplemented groups, virginiamycin was shown to benefit only the poorer producing hens. In Experiment 2, added fat improved feed efficiency; however, the response to virginiamycin, as observed in Experiment 1, did not occur.

Animals↗
PubMed1985

Effect of dietary manganese and age on tissue trace mineral composition of broiler-type chicks as a bioassay of manganese sources.

An experiment was conducted with 144 Cobb broiler-type chicks in a 4 X 3 factorial arrangement of treatments to investigate the effects of dietary manganese (Mn) and age on trace mineral composition in tissues. Day-old chicks were fed a basal corn-soybean meal diet (112 ppm Mn) supplemented with 0, 1000, 2000, or 3000 ppm Mn as manganese sulfate monohydrate (MnSO4 X H2O) for 1, 2, or 3 weeks. There were two pen replications per treatment combination and six chicks per pen. Liver, kidney, pancreas, skeletal muscle, and bone were excised from 4 chicks per replication. Plasma was pooled from the remaining 2 chicks, and all samples were frozen for subsequent mineral analysis. There was a reduction in average daily feed intake (P less than .05) at the 3000 ppm dietary level accompanied by a nonsignificant decrease in average daily gain and an increase in feed per unit gain. Tissue Mn increased (P less than .001) for all tissues as dietary Mn increased. Tissue Mn concentration was reduced with age in kidney, pancreas, muscle (P less than .001), and plasma (P less than .05). Manganese in bone was lowest (P less than .01) at 1 week of age. Of those ages tested, the optimum for bioassay based on lambda criterion values appeared to be 3 weeks. The highest lambda criterion values were obtained at 3 weeks of age in kidney followed by bone at 2 weeks. High dietary Mn increased copper (Cu) concentration in liver (P less than .05) and plasma (P less than .05) and reduced iron (Fe) in pancreas (P less than .001). Liver Fe was lower (P less than .001) at 3000 ppm than at 1000 or 2000 ppm dietary Mn. Plasma zinc (Zn) was higher (P less than .05) at all supplemental Mn levels than the unsupplemented control, and kidney Zn increased (P less than .001) at 3000 ppm dietary Mn.

Age Factors↗
PubMed1985

Influence of virginiamycin on phosphorus utilization by broiler chicks.

An experiment was conducted with day-old Cobb feather-sexed chicks to determine the influence of virginiamycin on phosphorus. When the average of the three levels of phosphorus were combined, utilization, body weights, and bone ash at 21-days of age were improved by the addition of virginiamycin to the diet. Also the amount of phosphorus required to produce a gram of body weight was decreased by the addition of virginiamycin to the diet.

Animals↗