bluuebunny/crossref_metadata_2025_split huggingface dataset:
Marginal cost of the calving interval in beef cows is not uniform
Authors: Raboisson Didier , Citerne Philippe 
Published: December 2017

To understand the profitability of reproduction management measures, an economic assessment based on a beef cow life simulation was proposed. It accounted for the discounted feeding costs of the dam and its calves for the different periods of their lives up to their sale and for the overall production from calves adjusted by mortality and culling. The calibration was proposed for various combinations of typical French and European situations. The maximal cash flow was observed for the lowest calving interval, corresponding to the maximal number of calves produced. The marginal cost of the calving interval was not uniform: on average, it was twice as high at a calving interval of 360 days (€1/day) as at 500 days (€0.5/day). It was also higher when age at first calving was lower and when culling was late or the replacement rate was low. The results were sensitive to the costs of the calves’ diets and to the market prices for calves. These assessments may assist the evaluation of the profitability of various measures taken in the field when faced with deteriorating calving intervals in beef production.
Letters to the Editor
Authors: Wagner Alexandra , Boos Joachim 
Published: December 2017

The following is the abstract of the article discussed in the subsequent letter: Hutson, Richard G., Toshiyuki Kitoh, David A. Moraga Amador, Sanja Cosic, Sheldon M. Schuster, and Michael S. Kilberg.Amino acid control of asparagine synthetase: relation to asparaginase resistance in human leukemia cells. Am. J. Physiol. 272 ( Cell Physiol. 41): C1691–C1699, 1997.—Complete amino acid deprivation in mammalian cells causes a significant enhancement in gene expression for a number of important cellular activities; among these is asparagine synthetase (AS). The data presented demonstrate that, in both nonleukemic (rat Fao hepatoma cells) and human leukemia cells (MOLT-4, NALL-1, and BALL-1), AS mRNA levels, protein content, and enzymatic activity are induced after incubation in an otherwise complete tissue culture medium that is deficient in a single amino acid or in medium that has been depleted of the amino acid asparagine by the addition of asparaginase. Complete amino acid deprivation results in a concerted increase in AS mRNA, protein, and enzymatic activity, which, in conjunction with previously published research, suggests that the mechanism of this cellular response involves transcriptional control of the AS gene. Asparaginase treatment is a standard component of acute lymphoblastic leukemia therapy for which the effectiveness is related to the inability of these cells to upregulate AS activity to a sufficient level. With regard to the asparaginase sensitivity of the three human leukemia cell lines, there was a trend toward an inverse relation to the degree of AS expression. Selection for asparaginase-resistant MOLT-4 sublines resulted in enhanced AS mRNA and protein content regardless of whether the cells had been selected by asparaginase treatment directly or asparagine was removed from the culture medium. Collectively, the data illustrate that further advances in asparaginase therapy will require additional knowledge of amino acid-dependent regulation of AS gene expression and, conversely, that asparaginase resistance represents a model system for investigating metabolite control in a clinically relevant setting.
Respiratory gases in uterine circulation of pregnant domestic swine as sampled by indwelling catheters
Authors: Caton D. , Bazer F. W. 
Published: December 2017

Data dealing with placental respiratory gas exchange are scant for species with an epitheliochorial placenta. None have been obtained from awake, unstressed animals. For this reason 18 pregnant swine were prepared with chronically implanted polyvinyl catheters. Respiratory gases in arterial and uterine venous blood were observed between the 30th day of gestation and term (110 days). There was a statistically significant relationship between uterine venous oxygen partial pressure (Po2 and the day of gestation. The value for Po2, fell from a mean of 70 to 57 Torr. The latter appears to be the highest mean value yet observed in uterine vein of any species at term. pregnancy; chronic preparation Submitted on March 7, 1977
Cold-induced thermogenesis in younger and older Fischer 344 rats following exercise training
Authors: McDonald Roger B. , Horwitz Barbara A. , Stern Judith S. 
Published: December 2017

Pages R908–R916: Roger B. McDonald, Barbara A. Horwitz, and Judith S. Stern. “Cold-induced thermogenesis in younger and older Fischer 344 rats following exercise training.” Page R912: the y-axis label of Fig. 4 should read: VO2 [ml/(min x kg body mass0.67)]. Page R913: substitute corrected Table 3: (See PDF)
“Alveolar plateau” of the single breath nitrogen elimination curve in normal subjects
Authors: Kjellmer Ingemar , Sandqvist Lars , Berglund Erik 
Published: December 2017

The single breath N2 elimination test, as standardized by Comroe and Fowler, has been used in normal subjects. The N2 difference, i.e. the difference in N2 concentration between Ve = 1250 and Ve = 750 ml, showed a tendency to increase with increasing volumes of inspired O2 and with increasing inspiratory flow rates. It decreased with increasing breath-holding time and was not consistently influenced by expiratory flow rate. The findings are compared with those of Fowler and of Shephard on normal subjects; different results were obtained, largely depending on different analytical procedures. These factors must be considered when evaluating results in patients. Submitted on July 21, 1958
Influence of abdominal muscles, mesenteric viscera and liver on respiratory mechanics
Authors: Brody Alfred W. , Connolly John J. , Wander Harry J. 
Published: December 2017

In a group of 13 supine, anesthetized cats initial measurement was made of respiratory elastance, total resistance by sinusoidal pressure, total resistance, k1 and k2 and their ratio of change from breath to breath, the natural frequency, damping factor and mass factor or inertance, and the functional residual capacity (FRC) and tissue resistance. Comparison was then made with the value obtained by remeasurement in the same cat after a) control operation of mid-line abdominal incision; b) incisions eliminating the effects of the abdominal muscles (mid-line vertical plus transverse incision extended to back); c) evisceration of gastrointestinal tract and spleen and d) evisceration plus hepatectomy. The abdominal response was found to be mainly a surface wave response (at a speed of about 150 cm/sec.) above the natural frequency. The abdominal muscles impose a steady force, more like a weight than a spring, which decreases the FRC. The liver contributes significantly to the mass factor and natural frequency, but the viscera do not. About half the tissue resistance consists of a resistance within the abdomen to respiratory movements; since nearly half the total resistance is tissue resistance, this is nearly one fourth the total resistance to respiration. Submitted on June 2, 1958
Fluid volume redistribution and thoracic volume changes during recumbency
Authors: Tenney S. M. 
Published: December 2017

Continuous measurements of change in center of gravity, thoracic and abdominal girths and extremity volume over a 30-minute period of recumbency were recorded in 20 normal young adults. Vital capacity, expiratory reserve volume and residual volumes were recorded at the beginning and end of the period. No significant differences between the initial and final vital capacities or residual volumes were observed. Expiratory reserve volume decreased and correlated positively with the measured change in torque. Abdominal and thoracic end expiratory circumferences both increased. Four young adults, normal except for congenital or traumatic absence of the lower extremities, were examined in the same manner. In these subjects the change in center of gravity was minimal and the thoracic circumference did not increase. The pattern of lung volume changes during recumbency was similar to normal subjects. It is concluded that during recumbency the lower extremities contribute blood to the thoracic pool and this is manifested as an increase in thoracic girth, but without decrease in total lung volume. The diaphragm assumes a more expiratory position and is partially responsible for the change in expiratory reserve volume. Submitted on August 4, 1958
Relationship of potassium and calcium to hypothermic ventricular fibrillation
Authors: Beavers William R. , Covino Benjamin G. 
Published: December 2017

Pentobarbital-anesthetized dogs, cooled in ice water to terminus, were found to have a 96% incidence of ventricular fibrillation. Plasma potassium levels were uniformly depressed at low body temperatures. Treatment with Intravenous potassium chloride, 150– 250 mg/kg, reduced the frequency of fibrillation to 57%. Administration of EDTA (ethylene diamine tetracetic acid), 75 mg/kg in divided doses, lowered serum calcium levels but affected the incidence of fibrillation only slightly. Combined therapy with potassium chloride and EDTA reduced the incidence of ventricular fibrillation to 50%. These results are interpreted as indicating that ionic imbalance observed with hypothermia produces a marked arrhythmic tendency and that proper alteration of plasma potassium levels reduces the danger of fibrillation. Submitted on July 28, 1958
Regional inhomogeneity of alveolar air and R.Q. differences in the lungs of the normal dog
Authors: Bechtel A. A. 
Published: December 2017

Regional inhomogeneity of alveolar air was studied by simultaneous sampling through catheters in primary or secondary bronchi, at the end of normal expiration in dogs under sodium pentobarbital anesthesia. With dogs lying on the back, the right lung usually had the lower Pco2, higher Po2 and higher R. P( t) < .001 for each difference. In the side-lying position the ‘down’ lung usually had the higher Po2 and R unless the catheters were placed so deep as to differentially obstruct the airway in that lung. Submitted on July 3, 1958
Quantitative studies of perception of thermal stimuli in the normal and neurogenic urinary bladder
Authors: McDonald Donald F. , Murphy Gerald P. 
Published: December 2017

Quantitative measurements of the ability of human beings to perceive temperature changes in the urinary bladder were made using copper-constantan thermocouples connected to a continuous recording electronic potentiometer. Ten different thermal changes were induced by irrigation of the bladder with cold or warm saline solution. Each stimulus was presented to each subject 10 times, according to a table of random numbers. The subjects were asked to indicate whether they felt warmer or colder. The stimulus was maintained for less than 3 seconds. In 40 normal volunteers, the mean warm response was 93℉. The mean cool response was 87.5℉. The neutrality point where the two curves intersected was 89.4℉. Statistical evaluation established the validity of the differences. The thermal sensation of seven patients with varying levels of spinal cord trauma seemed to indicate that the afferent pathway for thermal bladder sensation involved S2,3,4cord segments. Submitted on December 5, 1958
Circulatory adjustments of voluntary muscle in anemia
Authors: Verel D. , Duff R. S. 
Published: December 2017

Simultaneous measurements of the blood flow through the human forearm and of the arteriovenous oxygen difference of forearm blood have shown that in moderate anemia the need for oxygen was met by an increase in the arteriovenous oxygen difference without increase in blood flow. When the hemoglobin fell below 4 gm.% the blood flow rose. In subjects in whom the blood flow had increased, the venous oxygen saturation was below 15%. Cardiac output has been shown to increase when the hemoglobin falls below 8 gm.%. It is concluded that the initial increase in heart output is not due to ischemia of voluntary muscle but is required for maintaining the metabolism of the brain and the heart itself. Submitted on July 3, 1958
Diminished blood ATP levels induced in the chick by dietary aluminum hydroxide gel
Authors: Bishop C. , Williams C. , Rodbard S. 
Published: December 2017

When newly hatched chicks are placed on a diet containing a reactive aluminum hydroxide gel, the fatal syndrome of progressive leg and wing weakness which they develop is accompanied by a reduction in the quantity of adenosine triphosphate (ATP) in the blood. The intramuscular injection of an emulsion of inorganic phosphate tends to prevent this change. It is suggested that these chicks fed alumina gel are deficient in inorganic phosphate and that their reduced ability to maintain blood ATP levels is indicative of reduced phosphorylating ability elsewhere in the body. Submitted on November 13, 1958
Diffusion of water vapor through human skin in hot environment and with application of atropine
Authors: Buettner Konrad J. K. , Holmes Frederick F. 
Published: December 2017

At room temperatures between 20° and 40°C, vapor transfer through skin of human forearm was tested with four small heated bottles containing air of humidities ranging from 2 to 100% relative humidity. Exposure times ranging from 30 to 120 minutes had no influence on results. Water loss or gain of skin were observed for the different bottles. At very high humidities, liquid water deposit on the skin was measured by weighing a blotter. Skin vapor loss decreases systematically when bottle moisture increases. This increase is enhanced at room temperatures above 24℃, where total loss into a dry bottle increases more than fivefold. This increase seems only partially caused by sweat and partially by a decrease of the skin diffusion resistance. Tourniquet and locally applied atropine did not affect vapor transfer in a cool room. In a hot room, the tourniquet lowered the vapor loss by only 20%, whereas atropine drastically curtailed vapor loss. Submitted on August 25, 1958
Effect of posture on pulmonary dead space in man
Authors: Riley R. L. , Permutt S. , Said S. , Godfrey M. , Cheng T. O. , Howell J. B. L. , Shepard R. H. 
Published: December 2017

Physiologic dead space was determined in the supine and upright postures by simultaneous sampling and subsequent analysis of arterial blood and expired gas for Pco2. In seven normal men there was invariably a higher dead space in the upright than in the supine position. The difference averaged 83 ml and was statistically significant (S.E. 25 ml and P < 0.01). The ratio of dead space to tidal volume also invariably increased on assuming the upright posture. Evidence is presented for believing that most of the change in physiologic dead space resulted from a change in alveolar dead space. Estimated changes in the ratio of alveolar dead space to alveolar tidal volume suggest that approximately one seventh of the total number of alveoli became nonperfused on changing from the supine to the erect posture. These findings are consistent with bronchospirometric and hemodynamic evidence that the apex of the lung is virtually nonperfused in the resting human subject in the upright posture. Submitted on November 12, 1958
Comparison of vital capacity and maximum breathing capacity of athletes and nonathletes
Authors: Stuart Douglas G. , Collings W. D. 
Published: December 2017

The vital capacity (VC), maximum breathing capacity (MBC) and MBC/VC measurements of 20 athletes and 20 nonathletes were compared. The mean VC score of the athletes was significantly higher than the mean nonathlete VC, but insignificant differences existed between the two groups in MBC and MBC/VC. It is suggested that the difference in VC is due to increased development of respiratory musculature incidental to regular physical training. This increase is not reflected in the MBC since this measurement would appear to be more concerned with the presence or absence of obstructive ventilatory defects that are unaffected by physical training. Results are compared with data from the literature. Submitted on December 5, 1959
Ventilatory response to fixed acid evaluated by ‘iso-Pco2’ technique
Authors: Domizi Dario B. , Perkins John F. , Byrne Joan S. 
Published: December 2017

In order to avoid changes in a second stimulus to ventilation, i.e. carbon dioxide, while measuring the response to fixed acid, a technique was utilized whereby alveolar carbon dioxide tension (PaCOCO2) could be held constant. This technique includes continuous recording of PaCOCO2 with an infrared type analyzer and addition of sufficient CO2 to the inspired air to keep PaCOCO2 at its control value (near 40 mm Hg). The response of anesthetized dogs to infusion of 0.5 m HCl was measured when the PaCOCO2 was held at the control value and also at various other levels. Other experiments measured the effect of CO2 when it was not allowed to change arterial hydrogen ion concentration [H+]. It was found that both these substances are potent respiratory stimuli and that their effects may be considered essentially separate and additive, as suggested by Gray. The experiments also demonstrated a slightly increased sensitivity to CO2 at increased arterial [H+], but this effect was not found necessary to explain the response to acid. Responses to successive small increments in PaCOCO2 failed to reveal any ‘threshold,’ even with CO2 tensions as low as 15 mm during acidosis. Submitted on December 29, 1958
Breath holding after breathing of oxygen
Authors: Klocke F. J. , Rahn H. 
Published: December 2017

Following normal breathing of O2 seven untrained subjects held their breath beginning with a maximal inspiration. Breath-holding times ranged from 3.1 to 8.5 minutes and ‘breaking-point’ alveolar CO2 tensions from 51 to 91 mm Hg. Under these conditions, the maximum breath-holding time in minutes ( x) can be related to the rise in alveolar CO2 tension in mm Hg ( y), according to the equation x = 0.13 y + 1.4. After hyperventilation on O2, the breath-holding times were noticeably extended ranging from 6 to 14 minutes, but the breaking-point alveolar CO2 tensions did not exceed those noted above. In all cases, the measured changes in lung volume can be explained by the uptake of oxygen alone since the amount of CO2 is essentially unaltered during apnea. The decreases in lung volume observed are related to the total breath-holding time, about 13 minutes being required for a change in lung volume equal to the vital capacity. Three subjects were able to absorb their entire vital capacity volume during breath holding since no volume could be expired at the breaking point. Submitted on April 8, 1959
Response of Negro and white males to cold
Authors: Iampietro P. F. , Goldman R. F. , Buskirk E. R. , Bass David E. 
Published: December 2017

Heat production and body temperatures were measured in matched groups of U.S. Negro and white soldiers during whole body cooling and finger temperatures were measured when only the digits were cooled. Whole body cooling was accomplished by having the subjects, clad only in shorts, sit for 2 hours in a chamber at 50℉ with a 5-mph wind. Digital cooling was accomplished by having the subjects immerse the fingers in a water bath at 32℉ for 45 minutes. During whole body cooling there were no group differences with respect to the following: heat production, skin and rectal temperatures. During digital cooling white subjects had higher finger temperatures and the ‘hunting’ reaction was more pronounced than for Negroes. In addition, the white subjects required a shorter period for the onset of the first ‘rewarming’ of the fingers. The implications of these findings with reference to the reported higher incidence of cold injury among Negro soldiers are discussed. Submitted on February 19, 1959
Capillary resistance and blood pressure changes associated with pain due to local cooling: cold pressor test
Authors: McMurray Gordon A. , Jaques Louis B. 
Published: December 2017

Measurements of capillary resistance and blood pressure were made before and after immersion of the right hand in ice water for 5 minutes. The capillary resistance rose sharply immediately after stress and remained elevated for over 3 hours, returning to normal in 21 hours, while the blood pressure response reached its peak in 90 seconds. A significant negative correlation was found between the maximum changes in capillary resistance and blood pressure. Submitted on March 5, 1959
Requirements of sodium chloride during summer in the tropics
Authors: Malhotra M. S. , Sharma B. K. , Sivaraman R. 
Published: December 2017

Data are presented on salt requirements in the tropics, based on observations on 24 acclimatized Indian subjects given diets containing 16.2, 11.2, 8.7, 6.2 and 3.1 gm of salt per day. Adequacy of salt diet was tested from the chloride excretion in urine and from the changes observed in thiocyanate space and plasma chloride concentration at the start and after the subjects had been on the restricted salt diet for a week. Sweat and chloride losses at different environmental temperatures were studied. The salt requirement of subjects walking for 2 hours in the sun at a speed of about 3.5 mph was found to be about 6.2 gm/day when the mean maximum environmental temperature was 100.7℉ D.B. The requirement was found to increase by 0.063 gm/℉ rise in D.B. temperature for 2 hours' exercise. Submitted on September 12, 1958
Acetate metabolism in bovine ketosis
Authors: Kronfeld D. S. , Kleiber Max , Lucas J. M. 
Published: December 2017

The metabolism of intravenously injected acetate–1–C14 was compared in normal and ketotic cows. The mean standardized specific activity of milk citrate, casein, lactose, plasma glucose, respired carbon dioxide and urine acetone was greater in the ketotic than in the normal cows, while that of milk fat was markedly decreased. The total–C14 recovered in the milk fat within 48 hours was about 14% of the injected dose in the normal cows, but only about 3% in the ketotic cows. These results suggest that the proportion of acetate metabolized via the tricarboxylic acid cycle is increased, while milk fat synthesis from acetate is impaired during bovine ketosis. Submitted on December 15, 1958
Estimation of energy expenditure from pulmonary ventilation
Authors: Ford Amasa B. , Hellerstein Herman K. 
Published: December 2017

A method for estimating energy expenditure from pulmonary ventilation is presented and tested by analysis of 272 observations made under field conditions on 52 factory and steel mill workers. Energy expenditure (Calories/min.) equals 0.173 times ventilation (liters/min., BTPS), minus 0.52, with a standard error of estimate of 0.42 Calories per minute. The use of individual regression lines will permit more accurate estimation of energy expenditure when multiple observations are to be made on one subject. Submitted on June 10, 1959
Effect of lipemia on arterial oxygen at high altitude
Authors: Stutman Leonard J. , Kriewaldt Frank H. , Doerr Vern , George Marilyn 
Published: December 2017

Some of the effects of acute fat loading on arterial O2 at high altitude are described. Five dogs were taken to 12,000 feet in an altitude chamber and given fat infusions (1 gm/kg). There was a 10% drop in the arterial O2 content and a similar drop in the O2 capacity. One of the dogs had a surgically induced intra-atrial septal defect and died of fat emboli. Three dogs serving as controls at ground level had a 4% drop in arterial O2 content after fat infusions. A practical method for screening poor human risks among flying personnel, employing a fat tolerance test, is discussed. The drop in the O2 content and capacity of canine blood after fat infusions at 12,000 feet is at least twice that at ground level. Submitted on July 13, 1959