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Biomedical subjects

D L Ingram

Publications and source records attributed to D L Ingram.

At least 91 records · Page 5Linked to original sources
PubMed1975

Circulating polyribophosphate in Hemophilus influenzae, type b meningitis. Correlation with clinical course and antibody response.

In systemic infections caused by Hemophilus influenzae, type b, the capsular polysaccharide, polyribophosphate, is released into the circulation. Polyribophosphate was quantitated in serial serum and cerebrospinal fluid samples from 45 children with H. influenzae, type b meningitis by means of a radiolabeled antigen-binding inhibition assay. Polyribophosphate was regularly found in acute serum and cerebrospinal fluid samples and could be detected in unbound form for periods of 1-30 days after initiation of effective therapy. Complexes of polyribophosphate dissociable with acid and pepsin were detected in serum samples from 17 patients, in one case for a period of 145 days after hospitalization. Polyribophosphate levels and patterns of clearance were studied in relation to hospital course and antibody response. Patients with prolonged antigenemia had protracted fevers and severe neurological symptoms during hospitalization, frequently with focal complications.Antipolyribophosphate antibody responses were detected during the first 100 days of convalescence by radioimmunoassay in 79% of the patients studied, including 60% of the children 1 yr or less in age. The intensity of antibody response although clearly related to the age of the patient, was more reliably predicted by the efficiency of antigen clearance. Antibody responses were uniformly of low magnitude in patients with prolonged antigenemia, irrespective of age. Paients who failed to develop antibody to polyribophosphate after meningitis also exhibited impaired antigen clearance. These studies suggest that mechanisms necessary for clearance of polyribophosphate may influence the development and intensity of the humoral immune response and raise the possibility of developmental deficiencies in the clearance system in infants and children.

Age Factors↗
PubMed1974

The significance of deep body temperature in regulating the concentration of thyroxine in the plasma of the pig.

1. The activity of the thyroid gland in the pig has been assessed while thermosensitive regions of the hypothalamus or the spinal cord were cooled.2. If the cervical region of the spinal cord was cooled for 3 hr, by means of a thermode in the epidural space, the concentration of thyroxine in the plasma increased to a maximum within the first hour but fell again to the control level or lower within 2 hr of the onset of cooling.3. When a thermode in the preoptic region of the hypothalamus was cooled to 18 or 25 degrees C for 3 hr, the concentration of thyroxine in the plasma increased within the first hour and then declined again. Cooling the thermode to 10 degrees C led to a sustained increase in thyroxine concentration.4. The increase in the concentration of thyroxine in the plasma, on cooling the hypothalamus, was of a similar magnitude whether the ambient temperature was 25 or 15 degrees C.5. Observations on the disappearance of radioactive thyroxine from the plasma indicated that the distribution or metabolism of thyroxine was altered by the cooling of either the hypothalamus or the spinal cord.6. It was concluded that when the preoptic region of the hypothalamus or the cervical region of the spinal cord was cooled the rise in the concentration of thyroxine in the plasma was due at least in part to a change in the metabolism or distribution of thyroxine within the body and not entirely to the stimulation of the thyroid gland as has previously been suggested.

Animals↗
PubMed1973

The influence of body core temperature and peripheral temperatures on oxygen consumption in the pig.

1. The rate of oxygen consumption was measured in young pigs exposed to different ambient temperatures and the effect on metabolic rate of changing the temperature of thermodes implanted in the hypothalamus and over the spinal cord was determined. In some experiments the temperature of the skin over the trunk was changed by means of a water-perfused coat.2. Cooling the hypothalamus or the spinal cord in a warm ambient did not change the rate of oxygen consumption. At a thermoneutral ambient temperature, cooling either thermode increased oxygen consumption. In a cold environment, cooling either thermode increased the rate of oxygen consumption more than at a thermoneutral temperature. The increase in the rate of oxygen consumption was greatest during cooling of the spinal cord and it appeared that the pigs also shivered more violently. Heating either thermode tended to decrease oxygen consumption in a cold environment.3. In pigs with thermodes both in the hypothalamus and over the spinal cord, cooling both thermodes was accompanied by a greater increase in oxygen consumption than cooling either thermode alone. The increase in oxygen consumption on cooling one thermode could be reduced by heating the other.4. The skin temperature (fixed by the water perfused coat, or the ambient temperature) at which the rate of oxygen consumption increased, was lowered during heating of the thermodes, but the rate of increase in oxygen consumption appeared not to change as a function of falling skin or ambient temperature.

Animals↗
PubMed1973

The effects of heating and cooling the spinal cord and hypothalamus on thermoregulatory behaviour in the pig.

1. The effects of warming and cooling the spinal cord and hypothalamus on operant thermoregulatory behaviour and posture have been studied in the pig at neutral and cold ambient temperatures.2. Cooling the spinal cord increased and warming decreased the rate of obtaining thermal reinforcement. The response to cooling began with the onset of the stimulus and persisted for up to 5 min followed by a diminution in rate during the remaining 15 min of cooling. The peak of this ;on' response was greater the lower the ambient temperature. The response to heating was a small reduction in rate of reinforcement.3. The ;on' response to cooling the spinal cord was related to changes in temperature of only the cervical region of the cord.4. Cooling the hypothalamus led to an increase in the rate of obtaining heat and this increase was sustained during the 20 min of central cooling. Termination of cooling was followed by a marked depression in rate. Heating the hypothalamus had only a weak inhibitory effect on rate of reinforcement.5. While working for external heat during periods when thermodes over the spine and in the hypothalamus were not being cooled, pigs lay in ;cold defensive' prone positions 25% of the time and lay on their sides 75% of the time. During cooling of the spinal cord the time spent in the prone position was 95% at 5 and 15 degrees C ambients and 71% at a 25 degrees C ambient. During cooling of the hypothalamus the prone posture was adopted 50% of the time.6. When the temperatures of the spinal cord and of the hypothalamus were changed in opposite directions, the operant response was determined by the temperature of the hypothalamus while the postural response was most frequently determined by the temperature of the spinal cord.

Animals↗
PubMed1972

The influence of deep body temperatures and skin temperatures on respiratory frequency in the pig.

1. The influences on respiratory frequency of ambient temperature, the temperature of the skin, the temperature and humidity of the inspired air, hypothalamic temperature, the temperature of the spinal cord, rectal temperature and some temperatures in the abdomen have been studied in the pig.2. At a constant ambient temperature the effect on respiratory frequency of heating a thermode in the hypothalamus was modified by the temperature of the skin of the trunk which was varied independently by means of a temperature-controlled coat. A cold skin inhibited panting; a warm skin enhanced panting. The effect of heating a thermode over the spinal cord was similarly modified by skin temperatures.3. Simultaneous heating of thermodes in the hypothalamus and spinal cord increased respiratory frequency more than heating either alone, and in a warm environment the rectal temperature influenced the extent to which respiratory frequency increased on heating the thermodes.4. Cooling the thermodes decreased respiratory frequency in a warm environment and the cooling of one thermode enhanced the effect of cooling the other.5. At a constant trunk skin temperature the effect on respiratory frequency of heating the thermode in the hypothalamus depended on ambient temperature.6. Changing the temperature of thermodes in the abdomen did not affect respiration nor was there any evidence that the temperature and humidity of the inspired air had a direct effect on respiration.

Animals↗
PubMed1972

The influence of deep body and skin temperatures on thermoregulatory responses to heating of the scrotum in pigs.

1. The temperature on the surface of the pig's scrotum was increased by circulating water through a pad held over the scrotal surface while the animal was lightly restrained.2. At an ambient temperature of 25 degrees C there was no change in respiratory frequency even when the scrotum was heated to 42 degrees C, but peripheral blood flow did increase and body temperature fell. At 30 degrees C ambient temperature, respiratory frequency increased when the scrotum was warmed to 42 degrees C. At an ambient temperature of 32 degrees C, the frequency increased at a scrotal temperature of 40 degrees C and was even higher when the scrotum was 42 degrees C, but body temperature did not fall.3. At a constant ambient temperature the effect on respiratory frequency of heating the scrotum to a given temperature depended on the skin temperature of the trunk which was modified by means of a coat through which water was circulated.4. In a cold environment, heating the scrotum was accompanied by a fall in body temperature, the arrest of shivering and a decline in oxygen consumption.5. Cooling a thermode in the hypothalamus or over the spinal cord inhibited the increase in respiratory frequency and peripheral blood flow caused by heating the scrotum. Warming either thermode potentiates the effect of heating the scrotum.

Animals↗