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Biomedical subjects

D L Ingram

Publications and source records attributed to D L Ingram.

At least 73 records · Page 4Linked to original sources
PubMed1980

Plasma antidiurectic hormone during hypoxia and anaesthesia in pigs.

The level of antidiuretic hormone (ADH) in the plasma of pigs was studied during hypozia, anaesthesia and a combination of the two conditions. Hypoxia, caused by making conscious pigs breathe nitrogen, elicited a rise in the level of ADH without change in plasma osmolality; the hypoxia was accompanied in some cases by a slight lowering of arterial pressure which quickly returned to its original level after the period of hypoxic breathing. Pentobarbitone anaesthesia had no significant effect on the level of ADH but halothane anaesthesia elicited a rise in ADH. Transient high levels of ADH were seen in animals which were exposed to hypoxia during halothane or pentobarbitone anaesthesia. These high levels of ADH were sometimes, but not invariably, accompanied by a fall in arterial pressure. No consistent changes in plasma osmolality or haematocrit were associated with the raised plasma ADH.

Anesthesia↗
PubMed1979

Effect of dietary composition and cold exposure on non-shivering thermogenesis in young pigs and its alteration by the beta-blocker propranolol.

1. Young pigs were fed on three diets consecutively, each diet being given for 1 week. The diets were given in random order as (g pig feed/kg body-weight): (a) 20, (b) 60, (c) 20 plus a supplement with the energy equivalent of 40 g pig feed/kg. The supplements included desiccated coconut, fish meal and glucose. 2. At the end of each week resting metabolic rate, beginning 12--14 h after feeding, was measured overnight using an open-circuit respiration chamber at thermoneutrality. 3. The oxygen consumption of pigs on the 60 g/kg diet was always higher than on the 20 g/kg diet. The addition of desiccated coconut, or fish meal also increased metabolic rate; whereas with added glucose, O2 consumption tended to be even lower than on 20 g/kg alone. 4. The administration of the beta-blocker propranolol to pigs on ad lib, food intake reduced the rate of overnight resting O2 consumption, measured from 10 until 20 h after feeding, by 12%, but it had no effect on O2 consumption when the intake was 20 g feed/kg. Exposure to mild cold (15 degrees) caused an increase in O2 consumption and this was reduced by 14% after injection of propranolol.

Animals↗
PubMed1979

The relative importance of thermal, osmotic and hypovolaemic factors in the control of drinking in the pig.

1. The influence of thermogenic, osmotic or hypovolaemic stimuli on drinking has been measured in young pigs. Temperature changes in the hypothalamus and spinal cord were induced by means of implanted thermodes, while peripheral changes in skin and scrotal temperature were induced by circulating water through a coat. Osmotic stimuli were applied by I.V. injections of NaCl and hypovolaemia was induced by withdrawal of blood. 2. At an ambient temperature of 21--24 degrees C warming the hypothalamus for 10 min increased the water intake approximately 40%, while cooling the hypothalamus for a similar period reduced it by about 70%. 3. At an ambient temperature of 21--24 degrees C warming the scrotum caused the pigs to drink more than controls, and at the higher ambient temperature of 32 degrees C the effect was even greater. 4. Warming or cooling the spinal cord produced effects that were not consistent either within or between animals, thus temperature changes in this region play, at most, a minimal physiological role in the control of drinking in the pig. Warming the skin to 40 degrees C produced a slight increase in water intake, as also did cooling of the skin. 5. Drinking induced by an osmotic stimulus was proportional to the concentration of NaCl ranging from 5 to 30%. 6. Withdrawal of 500 ml. blood did not produce a statistically significant increase in water intake compared with controls.

Animals↗
PubMed1979

Methods for serotyping nasopharyngeal isolates of Haemophilus influenzae: slide agglutination, Quellung reaction, countercurrent immunoelectrophoresis, latex agglutination, and antiserum agar.

Nasopharyngeal isolates of H. influenzae were typed by the slide agglutination test, the Quelling reaction, the latex agglutination test, countercurrent immunoelectrophoresis, and the antiserum agar test. These tests gave essentially comparable results, with countercurrent immunoelectrophoresis and latex agglutination being slightly more sensitive. Cross-reactive problems encountered with latex agglutination and the expense of performing countercurrent immunoelectrophoresis or the antiserum agar test made these tests less practical than the slide agglutination test to identify single strains that were already isolated. The Quellung reaction and slide agglutination were the most rapid tests used to type an organism. For mass screening of multiple samples, countercurrent immunoelectrophoresis was the simplest technique. The antiserum agar test was slow but was the best technique to screen nasopharyngeal swab cultures to identify the presence of any encapsulated strains in the mixed flora. Whether any of the above techniques were as sensitive as the immunofluorescence test was not evaluated in this study.

Agar↗
PubMed1978

Responses of the pituitary-adrenal system of the pig to environmental changes and drugs.

1 The reactivity of the pituitary-adrenal axis of the young pig was tested for its suitability as a sensitive index for any discomfort that might be experienced under certain conditions of intensive husbandry.2 In a thermoneutral environment, most undisturbed piglets showed only slight variations in the plasma concentrations of adrenocorticotrophic hormone (ACTH) and corticosteroids.3 Stimuli such as exposure to ambient temperatures of +40 degrees C or -5 degrees C were required to cause large rises in the plasma concentrations of ACTH and corticosteroids.4 Apparently milder stimuli, such as change of environment, slight frustration or changes in ambient temperatures between +5 degrees C and +30 degrees C only rarely caused a significant rise in plasma corticosteroids. Thus changes in plasma corticosteroid concentrations are not a sensitive index for the reaction of a piglet to its environment.5 Increases in plasma ACTH concentrations occurred faster than those of the corticosteroids, were larger when expressed as a percentage of the basal values and occurred following relatively small disturbances such as omission of the reward in an operant behaviour test when corticosteroid changes were often not detectable. Thus rises in plasma ACTH might be a useful indication that a given situation is disturbing to a pig. The reaction of plasma ACTH concentrations to chronic irritations as they might occur in intensive husbandry remains to be investigated.6 Azaperone (2 mg/kg i.m.), a drug which is used as a sedative in pigs, caused a rise of about 50% in plasma corticosteroid concentrations. It did not diminish the large steroid output seen when the animals were exposed to high and low ambient temperatures.

Abdomen↗
PubMed1977

Adaptations to ambient temperature in growing pigs.

1. Pigs were weaned at 8--10 dyas of age and littermate pairs were raised in individual cages at ambient temperatures of 25 degrees C or 35 degrees C to 8 weeks of age. 2. Pigs reared at the higher temperature had longer extremities and less hair than controls even though body weights were similar. 3. On exposure to an ambient temperature of 45 degrees C, thce as quickly as their littermates. 4. When the scrotum was heated locally to 42 degrees C animals reared in the warmer environment began to pant at a lower ambient temperature than the controls. 5. Heating the hypothalamus by means of an implanted thermode at an ambient temperature of 35 degrees C was accompanied by an increase in respiratory frequency in pigs reared at 25 degrees C. The pigs reared at 35 degrees C already had a slightly elevated rate of breathing and heating the hypothalamus caused no change. 6. The rate of blood flow in the tail was higher in pigs reared at 25 degrees C than those kept at 35 degrees C when measured at ambient temperatures between 20 degrees C and 35 degrees C. When the hypothalamus was cooled the slope of the line relating blood flow to the temperature of the thermode was similar in both groups. 7. The critical temperature as determined from measurements of oxygen consumption was higher in the pigs reared at 35 degrees C than in controls. But the effect of cooling the hypothalamus on metabolism was similar in both groups. 8. There was no difference between the two groups in the rate of cutaneous water loss.

Acclimatization↗
PubMed1977

Antibody of polyribophate of Haemophilus influenzae type b in infants and children: effect of immunization with polyribophosphate.

Antibody to polyribophosphate, the capsular polysaccharide of Haemophilus influenzae type b, was measured in healthy ambulatory children by a radioactive antigen-binding assay. Titers fell from birth through nine months of age, then increased until six years, when they plateaued. Antibody activity was not correlated with the child's sex, ethnic status, or area of residence. Doses of 0.2-50 microgram of polyribophosphate given as single or booster doses had similar effects on antibody activity. Of 368 doses given to infants two to six months of age, 7% produced a significant antibody response; of 95 doses given to infants seven to 12 months old, 17% produced a response. The geometric mean titers of antibody resulting from immunization with polyribophosphate given at various times in relation to diphtheria-pertussistetanus vaccine did not differ significantly from one another or from titers observed in infants given only the latter vaccine. These data indicate that purified polyribophosphate will not provoke humoral immunity in young infants against H. influenzae type b and that it should no longer be considered as a candidate vaccine for this purpose.

Age Factors↗
PubMed1977

The effect of ambient temperature upon the secretion of thyroxine in the young pig.

1. Fluctuations in the rate of secretion and metabolism of thyroxine in the pig were observed whilst the ambient temperature was reduced from 32 to 8 degrees C. The quantity of food supplied was either maintained constant or doubled when the animals were exposed to the lower temperature. 2. It was found that the rate of disappearance of [125I]thyroxine did not change when the animal was exposed to the cold, unless the animal's food intake was altered. 3. The secretion of thyroxine increased temporarily after exposure to the cold. This was shown by a rise in the concentration of thyroxine in the plasma and a simultaneously increased loss of 131I from the thyroid gland. The increase in secretion of thyroxine was not maintained throughout the exposure to cold when the food intake of the animal was kept constant.

Animals↗
PubMed1977

The influence of food intake and ambient temperature on the rate of thyroxine utilization.

Young growing pigs of both sexes were subjected to changes in (1) energy intake, (2) ambient temperature, and (3) bulk of food. The rate of disappearance of injected 125I-labelled thyroxine from the plasma (K) was measured. An analysis of variance revealed that the effect attributable to changes in the energy content of the food intake was statistically significant (P less 0-01). A change in ambient temperature had no statistically significant effect on K, nor did a change in the bulk of food when energy intake was constant (P less than 0-05).

Analysis of Variance↗
PubMed1977

Thermal effects of reproductive hormones on the sheep udder.

The thermal effect of reproductive hormones on the sheep udder was tested in five ewes at the end of their breeding season. Radiotelemetry was used to provide continuous recordings of deep body temperature (Tb), udder skin temperature (Tud), and back skin temperature (Tbk) while the animals were held in a controlled-environment isolation chamber. Injections of estradiol (1.0 and 2.5 mg, im) resulted in an increase in Tud, but not in Tb, and only occasionally in Tbk. The amplitude of the rise in Tud varied from 0.4 to 3.8 degrees C and the rise persisted over 48 h following injection. Injections of saline, prostaglandin (PGF2alpha), or progesterone did not affect Tud, and injections of pyrogen (typhoid vaccine) elicited only an insignificant change in Tud concurrent with substantial increases in Tb and Tbk.

Animals↗
PubMed1976

Effects of various ambient temperatures and of heating and cooling the hypothalamus and cervical spinal cord on antidiuretic hormone secretion and urinary osmolality in pigs.

1. Plasma ADH concentration, urinary and plasma osmolality and haematocrit were measured in young pigs placed in cold, thermoneutral, warm and hot ambient temperatures. In some experiments a thermode placed in the hypothalamus or over the cervical spinal cord was heated or cooled at various ambient temperatures. 2. Plasma ADH concentration remained at a low level (0-5--5 muu. ml.-1) over 2 hr or 3 hr periods when the pigs were in cold, thermoneutral or warm ambient temperatures. A hot environment, which caused a marked rise in the pigs' rectal temperature, was associated with a large rise in plasma ADH level. 3. The rise in plasma ADH level which occurred during an increase in body temperature was consistently and completely suppressed by simultaneous cooling of the thermode in the pre-optic region to 5 to 10 degrees C. When the thermode was in the region of the supraoptic nucleus the rise in ADH was only partly suppressed, and when it was over the cervical cord it was only sometimes suppressed. 4. Cooling the thermodes in any position at a cold or thermoneutral ambient temperature, or heating them at a thermoneutral or warm ambient temperature, caused no consistent change in ADH. 5. A diuresis, with a urinary flow-rate of at most 1 ml. min-1 and minimal urinary osmolality of 53 m-osmole kg-1, was observed on only three occasions, twice during cooling of a thermode in the hypothalamus and once after the end of a period when the thermode was heated. In each case, the plasma ADH was less than 2 muu. ml.-1. 6. A slight rise of haematocrit in cold ambient conditions and a slight fall in the warm were observed. Otherwise changes in haematocrit were trivial, and a shift of water between vascular system and interstitium could not be invoked to account for changes in ADH levels. Observed variation of plasma osmolality was also slight.

Animals↗
PubMed1975

The efficiency of operatnt thermoregulatory behavior in pigs as determined from the rate of oxygen consumption.

Pigs were trained to perform an operant response for a reinforcement of radiant heat and comparisons were made between oxygen consumption during sessions when extra heat was available and others when it was not. It was found that as judged by the rate of oxygen consumption the efficiency with which heat was obtained was very high when the radiation was allowed to increase air temperature, but declined when air temperature remained low. If the pig had to make several responses for a single reinforcement, there was no saving in oxygen consumption. Reducing the intensity of the heating led to a reduction in the frequency at which responses were made. When the reinforcement was a brief respite from a draught, the pigs performed a greater number of responses at low ambient temperatures, but this was not accompanied by any saving in the rate of oxygen consumption.

Air Movements↗
PubMed1975

Variations in behavioral thermoregulation in the young pig over 24 hour periods.

Young pigs were trained to make a response to obtain a reinforcement of radiant heat. The animals were kept by themselves in a temperature-controlled light-proof room. Some pigs were kept in constant light, some were subjected to a light/dark cycle, and some were first fed ad lib and then deprived of food. The results were analysed by fitting a cosine curve using regression methods and evidence of a circadian rhythm was obtained under all conditions and at ambient temperature between 5 degrees and 20 degrees centrigrade. Most pigs had a peak demand for heat during the true daytime, but in two pigs the peak occurred at night.

Animals↗