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Biomedical subjects

D L Ingram

Publications and source records attributed to D L Ingram.

At least 37 records · Page 2Linked to original sources
PubMed1987

Heat production and respiratory enzymes in normal and runt newborn piglets.

The heat productions of newborn runt and normal piglets were estimated over a range of ambient temperatures. Most runts increased their heat production in the cold, but when expressed as J X kg-0.67 X min-1 it was significantly lower than in normal piglets (201.3 +/- 16.0 and 144.7 +/- 16.2 J X kg-0.67 X min-1 for controls and runts, respectively, at 32 degrees C). Runts consequently had lower deep body temperatures (37.8 +/- 0.2 and 36.8 +/- 0.3 degrees C for controls and runts, respectively, at 32 degrees C). Some runts failed to increase their metabolic rate in the cold and these had the lowest deep body temperature. Activities of respiratory enzymes in heart and diaphragm muscle were similar in all animals, whereas the longissimus dorsi of runts had significantly lower enzyme activities (76.3 +/- 4.2 and 55.5 +/- 6.6 in absorbance units for controls and runts, respectively).

Animals↗
PubMed1986

Effect of diet and temperature acclimation on thermoregulatory behaviour in piglets.

Piglets were weaned at 14 days and acclimated to 10 or 35 degrees C and kept either on a low or a high plant of nutrition. After 2 and 3 weeks of acclimation their operant thermoregulatory behaviour was observed at 15 degrees C. The pigs which had been living at 10 degrees C obtained more radiant heat than those from 35 degrees C and the animals on a low energy intake obtained more reinforcements than those on a high intake. There was no interaction between temperature and diet indicating that these two variables exerted their influence independently. Pigs tested 22 hr after a meal obtained more heat than when tested 1 hr after a meal. Rectal temperature before the test was significantly lower in the animals reared at 10 than at 35 degrees C, but the difference had disappeared at the end of the trial. By contrast, the pigs kept on different planes of nutrition had the same rectal temperatures before the test trial but afterwards the animals on a high diet had higher rectal temperatures. Body temperatures seemed to be the factor which influenced the demand for heat. The role of thermal comfort, body size, diet induced thermogenesis and separate sets of controls for autonomic and behavioural thermoregulatory responses in operant thermoregulatory behaviour is discussed.

Acclimatization↗
PubMed1986

Influence of a single meal on fractional disappearance and catabolic rates of 3,5,3'-triiodothyronine and thyroxine over 24 hours.

The influence of a single meal on the rates of catabolism of 3,5,3'-triiodothyronine (T3) and thyroxine (T4) was investigated in young pigs. Plasma hormone concentrations, fractional disappearance rates (K), distribution volumes and catabolic rates were estimated during three periods after a meal. For T3, plasma concentration and K were greatest immediately after the meal and decreased progressively. Catabolic rate decreased from 0.45 nmol.hr-1.kg-1 immediately after the meal to 0.28 nmol.hr-1.kg-1 after 24 hr. In a separate investigation, a meal was found to cause an increase in plasma [125I] T4, indicating a shift in the distribution of the hormone pool. Catabolic rate of T4 appeared to be greatest in the period immediately after the meal and decreased to 0.43 nmol.hr-1.kg-1 nearly 24 hr later.

Animals↗
PubMed1986

Use of rapidly generated results in patient management.

The usefulness of a rapid diagnostic test in patient management depends on the sensitivity of the test, the clinical consequences of false-negative or false-positive results, the ease and cost of performance, and the timely availability of results. A test that is sensitive, specific, inexpensive, and rapid is presumed to be useful clinically. However, there has been surprisingly little effort to measure the actual impact of the results on patient care. Since antigen detection for Haemophilus influenzae type b disease has been available for more than a decade, it will be used as a model to illustrate several factors that help determine the benefits, limitations, and pitfalls of antigen detection in the management of patients with serious bacterial infections. Herein we will compare the use of antigen detection in meningitis with that in other Haemophilus influenzae type b diseases. We also will review our experience with the impact of rapid diagnosis on the treatment of bacterial meningitis. Finally, other factors that influence the usefulness of antigen detection on patient care will be explored by comparing the potential consequences of laboratory error on the management of patients with Haemophilus influenzae type b infections with that of management of other kinds of infections, such as streptococcal pharyngitis, sexually transmitted diseases, and viral respiratory infections.

Antigens, Bacterial↗
PubMed1986

Role of thyroid hormones in the modification of diet-induced thermogenesis by propranolol.

The effect of thyroid hormones on the reduction in resting metabolic rate by the beta-blocker propranolol has been investigated in young pigs. Oxygen consumption was measured 12 to 20 hr after the last meal in euthyroid and hypothyroid animals on a high or low level of energy intake. The increase in resting metabolic rate in animals on the high energy intake was reduced by propranolol in the euthyroid controls but not in those animals made hypothyroid by methimazole. Thus at least part of the action of propranolol to decrease diet-induced thermogenesis depends on its interaction with thyroid hormones.

Animals↗
PubMed1986

The effect of day length on the duration of pregnancy and the onset of parturition in the rat.

Rats mated under normal lighting conditions of a 24 h day were transferred to a sound-proof room with period lengths (T) of 24 h (12 h light and 12 h dark, 12L:12D), or 22 h (11L:11D). During the first 15 d of pregnancy the rats were kept together in a large enclosure and the locomotor activity of the group was recorded. From day 15 they were kept separately, in cages, and from day 21 the number of litters born was noted every 3 h. On 12L:12D, rats displayed well defined periods of activity which were closely related to photoperiod. Mean activity was greatest in the dark, and overall activity declined after day 13 of gestation. On 11L:11D, coupling of locomotor activity to the dark phase was retained initially, but was not sustained throughout the period of study. Activity in the light was comparable to that in the dark at the time when the light:dark cycles of 11L:11D became reversed relative to those of 12L:12D. Rats on a 24 h day had a peak time of delivery at 519 h after mating (21.6 cycles of 12L:12D) and those on a 22 h day at 527 h (24.0 cycles of 11L:11D; difference, P less than 0.002). The 11L:11D cycle therefore increased rather than decreased the duration of pregnancy, implying that elapsed time rather than the number of light:dark cycles experienced has the greater influence on the length of gestation. Of the animals on a 24 h day 76% had their litters in the light phase of the cycle, whereas only 36% of those on a 22 h day gave birth in the light (P less than 0.02).

Activity Cycles↗
PubMed1986

Alteration of lactase and aminopeptidase N expression in porcine enterocytes by energy intake and environment.

The influence of nutrition, environmental temperature and time of feeding on lactase and aminopeptidase N activities in enterocytes of young pigs has been investigated. Animals were kept in the cold (10 degrees C) or warm (35 degrees C) and given either a high or low energy intake. In animals from the cold, lactase activity as determined by scanning microdensitometry was significantly lower at 4 h after a meal than it was in animals from the warm. At 6 h, the activities were similar in all groups, while at 20-24 h after feeding, lactase activity was much greater in those kept at 10 degrees C than in those at 35 degrees C. Level of energy intake had no statistically significant effect and no differences were found with respect to aminopeptidase N. The possibility that these differences in lactase activity are related to thyroid hormone metabolism and energy supply in relation to demand is discussed.

Aminopeptidases↗
PubMed1985

Synchronization of motor activity in young pigs to a non-circadian rhythm without affecting food intake and growth.

The influence of length of light:dark cycle on motor activity, food intake and growth has been investigated in young pigs subject to either 12 hr light:12 hr dark, or 9 hr light:9 hr dark. Motor activity was positively correlated with the light phase in both groups. No differences were found in growth rate or in the average amount of food eaten in a 72 hr period between the two treatments. Body conformation and composition were also similar. Thus, unlike many other mammals the young pig can synchronize its activity to a non-circadian rhythm. Moreover, this does not affect growth.

Animals↗
PubMed1985

Conversion of thyroxine into 3,5,3'-triiodothyronine and 3,3',5'-triiodothyronine in the young pig.

Estimates have been made of the amounts of 3,5,3'-triiodothyrone (T3) and 3,3',5'-triiodothyronine (rT3) derived from peripheral deiodination of thyroxine (T4) in young pigs. Two methods were used. The first depended on the assumption that deiodination occurs at the same rate in normal animals and in thyroidectomized animals on T4 replacement therapy. The second on the assumption that T3 and rT3 are secreted in the same proportions as they occur in thyroglobulin. The first method arguably gives the better estimate which is that 87% of circulating T4 is monodeiodinated to T3 and rT3. Peripheral conversion accounts for 76 and 69% of the circulating T3 and rT3, respectively.

Animals↗
PubMed1985

Influence of environmental temperature and energy intake on porcine skeletal muscle mitochondria.

The influence of acclimation to a cold (10 degrees C) or warm (35 degrees C) environment on the functional characteristics of skeletal muscle mitochondria has been investigated in young pigs on a high (H) or low (L) energy intake. Living at 10 degrees C increased the amount of mitochondrial protein and the concentration of cytochrome. Ca2+-stimulated succinate oxidation by mitochondria from the 35H group was tightly coupled and similar to that in pigs living under normal husbandry conditions. Mitochondria from the three other groups were readily uncoupled and thus resembled those from pigs susceptible to malignant hyperthermia. Arrhenius plots of State 3 Ca2+-stimulated succinate oxidation showed that energy intake altered the transition temperature suggesting possible differences in the structure of the mitochondrial membrane.

Adenosine Diphosphate↗
PubMed1985

Effect of long term differences in energy intake on metabolic rate and thyroid hormones.

Long term effects of differences in energy intake on thyroid hormone metabolism and the rate of oxygen consumption were studied in two groups of young pigs. The pigs were kept at 25 degrees C and fed either a high (H) or low (L) energy intake such that H = 2L for six weeks. The rate of oxygen consumption, the plasma levels of thyroxine (T4) and 3,5,3'-triiodothyronine (T3) and the fractional rate of disappearance of T4 and T3 were measured each week. The metabolic rate at thermal neutrality was lowest in the animals on the L intake and the critical temperature was lowest in the pigs on the H intake. These differences tended to increase with time. The fractional disappearance rate (K) for T4 began by being greater in the animals on the H intake, but after four weeks the difference reversed. The catabolic rate of T4 in nmol.kg-1h-1 showed similar changes. The k values for T3 were not significantly different between treatments. It is tentatively suggested that the different energy intakes lead to a change in the tissue sensitivity to thyroid hormone.

Animals↗
PubMed1985

An analysis of some behavioural effects of the vibration and noise components of transport in pigs.

The reactions of pigs to the vibration and noise components of transport were examined with the use of an apparatus which simulated these factors. The pigs were trained to switch off the apparatus by pressing a switch panel with their snouts. It was found that vibration was aversive but that noise was not. The pigs switched off the apparatus more frequently when the vibration was fast and when they had been fed a large meal before the test. Although the sedative tranquillizing drug azaperone decreased the number of times the apparatus was switched off, the effect appeared to be non-specific because azaperone also reduced the number of responses that pigs would make in order to receive food.

Animals↗
PubMed1984

Carbohydrate-induced thermogenesis and its modification by the beta-blocker propranolol.

Thermogenesis induced by carbohydrates of differing chemical complexity has been investigated. In piglets aged 6-10 weeks and fed standard feed, doubling the energy intake with glucose did not alter the resting oxygen consumption 12-21 hr after a meal. Addition of sucrose or glucose polymer to standard feed increased the resting rate of oxygen consumption slightly. Nevertheless the rate was still considerably less than after a meal of complex carbohydrate. Although propranolol had no effect on metabolic rate immediately after a meal high in glucose, it reduced the rate significantly after 7-15 hr.

Analysis of Variance↗
PubMed1984

Granular cell tumors of the breast. Steroid receptor analysis and localization of carcinoembryonic antigen, myoglobin, and S100 protein.

Granular cell tumors occur in a variety of sites, including the breast (6%). Origins from histiocytic, myogenic, fibroblastic, and neurogenic elements have been proposed. Female predominance suggests that estrogenic hormones are involved. Four granular cell tumors of the breast and one in an axillary lymph node were studied for sex steroid receptor content, myoglobin, carcinoembryonic antigen, and S100 protein localization. Antimyoglobin antibody did not localize in these tumors. Carcinoembryonic antigen and S100 protein localized in the cytoplasm of these tumors. Neither estrogen nor progesterone receptor protein were present in these tumors in detectable amounts. Ultrastructural features of these granular cell tumors in the breast are similar to those described for extramammary granular cell tumors. These studies agree with previous data that suggest a neurogenic origin for granular cell tumors.

Breast Neoplasms↗
PubMed1983

Changes in food intake in response to alterations in the ambient temperature: modifications by previous thermal and nutritional experience.

1. The influence of ambient temperature on ad libitum food intake has been investigated in piglets weaned at 2 weeks and kept in the hot (35 degrees C) or the cold (10 degrees C) on a high or low energy intake for 6 weeks. Further, the extent to which food intake was correlated with fasting body temperatures and resting metabolic rate was also examined. 2. The amount of food eaten in a single meal was recorded daily in two series of tests. In Test I, measurements were made both at the normal living temperature and after 2 and 24 h at thermal neutrality (25 degrees C). In Test II, the animals were examined at 25 degrees C over a 4 day period. Resting metabolic rate and body temperatures were also measured, immediately before the measurement of food intake. 3. Food intake was much greater at 10 than at 35 degrees C, but even at thermal neutrality it was significantly higher for those which had been in the cold. This was true for periods of between 2h and 4 days at 25 degrees C. Although food intake was not correlated with skin or core temperatures, there was an indication of a correlation with metabolic rate, particularly at thermal neutrality. 4. The results show that long-term cold exposure has a lasting effect on food intake, even at thermal neutrality, and it is suggested that this may be related to hormonal changes.

Acclimatization↗
PubMed1983

Influence of thermal and nutritional acclimatization on body temperatures and metabolic rate.

1. An investigation of the influence of previous thermal and nutritional experience on body temperatures and metabolic rate has been carried out with growing piglets. Littermates were kept, from shortly after birth, at either 10 or 35 degrees C and fed either a high (H) or a low (L) energy intake. At 8 weeks of age the animals were exposed to a series of environmental temperatures of 10, 20, 27 and 35 degrees C for 1.5 hr and their rates of oxygen consumption were determined over the last 45 min. At the end of the session body temperatures were measured. 2. Rectal temperatures measured 24 hr after the start of the last meal were higher at each test temperature in piglets which had been living at 35 degrees C than in those at 10 degrees C. Also, rectal temperatures were higher in those on the H intake for animals which had been living in either the hot or the cold environment. 3. Skin temperature on the back was similar in all groups at any given test temperature although there was a tendency for those on an H intake to have the higher temperatures. Skin temperatures of the legs and ears were higher in the 10H and 10L groups than in the 35H or 35L groups at all the test environmental temperatures; energy intake had little effect. 4. Metabolic rate was greater for the animals on the H than the L intake, for those which had been living at either 10 or 35 degrees C at all the test environmental temperatures. The analysis did not reveal any significant difference related to the overall effect of living temperature, which was independent of energy intake. 5. At thermal neutrality (27 degrees C) there was a significant interaction, between energy intake and normal living temperature, on metabolic rate. Living temperature was found to modify the effect of intake: the difference between the two intakes was greater in those from the cold environment than from the hot.

Acclimatization↗