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Biomedical subjects

D L Ingram

Publications and source records attributed to D L Ingram.

At least 109 records · Page 6Linked to original sources
PubMed1971

The influence of deep body temperatures and skin temperatures on peripheral blood flow in the pig.

1. The rate of blood flow through the tail of the pig has been measured by means of venous occlusion plethysmography using a mercury in rubber strain gauge. Conscious animals were used in all experiments because previous work had demonstrated that anaesthetics interfere with the animal's ability to vasoconstrict.2. Graded changes in the temperature of the hypothalamus were imposed by means of an implanted thermode. It was found that the change in blood flow depended on the extent of the change in hypothalamic temperature and on the ambient temperature. Below 20 degrees C ambient temperature, heating the hypothalamus did not cause vasodilatation and at 30 degrees C ambient temperature, cooling the hypothalamus caused only slight vasoconstriction, but at 25 degrees C ambient temperature, changes in hypothalamic temperature caused changes in blood flow from full vasoconstriction to full vasodilatation.3. The skin temperature on the trunk was changed by means of water circulated through tubes sewn into a coat worn by the pig. Blood flow in the tail, which was outside the coat, depended on the skin temperature of the trunk, the ambient temperature, and the temperature of the hypothalamus, all of which were varied separately.4. A thermode was implanted in the epidural space in the cervical region of the spinal cord. The change in blood flow in the tail which accompanied a change in thermode temperature was found to depend on the temperature of the thermode and the ambient temperature. Cooling the spine while the hypothalamus was being heated to 43 degrees C resulted in a decrease in blood flow, but when the spine was heated while the hypothalamus was being cooled the increase in blood flow was only slight.5. Local stimulus to the tail in the form of infra-red heat, or increased air movement was followed by changes in blood flow even when deep body temperature remained stable.

Animals↗
PubMed1970

Variations in deep body temperature in the young unrestrained pig over the 24 hour period.

1. The temperature near the carotid artery has been measured in the unrestrained pig by means of radiotelemetry. When the animals were housed singly under constant conditions of temperature and lighting the temperature rhythm appeared to be related only to the time of feeding. A similar record was obtained from temperature measurements made in the hypothalamus.2. Over the range of ambient temperatures 10-30 degrees C the mean body temperature was 38.8 degrees C. No consistent variation occurred with ambient temperature, but on initial transfer from 10 to 30 degrees C ambient temperature the body temperature decreased, while on initial transfer from 30 to 10 degrees C it increased.3. When one pig was housed in a hut with a small outside yard a nychthemeral rhythm was sometimes superimposed on that imposed by feeding. When two pigs were kept in a paddock containing a hut the nychthemeral rhythm was more pronounced.4. It is concluded that in the pig there is very little innate circadian temperature rhythm and that the temperature variations seen are related chiefly to feeding and activity.

Animals↗
PubMed1968

The influence of hypothalamic temperature and ambient temperature on thermoregulatory mechanisms in the pig.

1. Two types of temperature fluctuation have been recorded from the preoptic region of the conscious pig. One, which is associated with arousal or movement, and another, which is related to rhythms in respiration and blood pressure.2. When the pigs were subjected to infra-red irradiation at various ambient temperatures it was found that there was no precise temperature of the preoptic region at which the respiratory frequency increased.3. Local heating of the preoptic region was effective in increasing the respiratory frequency only when the ambient temperature was above 30 degrees C.4. Even when both the peripheral temperature and central temperatures were increased there was a delay of several minutes before the onset of panting.5. Cooling the preoptic region of the hypothalamus prevented the onset of panting in a hot environment, and reduced respiratory frequency in an animal which was already panting.6. Oxygen consumption was reduced in a cold environment when the preoptic region was warmed, and increased when it was cooled. No increase in oxygen consumption occurred when the hypothalamus was cooled in a hot environment.

Animals↗
PubMed1967

Effect of heating & cooling the hypothalamus on behavioral thermoregulation in the pig.

1. Pigs were trained to push a switch with their snouts in order to obtain a short burst of infra-red heat on the skin.2. When the preoptic region of the hypothalamus was cooled by means of an implanted thermode, the rate at which the heaters were turned on increased at environmental temperatures ranging from 0 to 25 degrees C. At 30 and 35 degrees C cooling sometimes had no effect.3. The preoptic region was warmed either by means of a thermode or using radio-frequency heating from implanted electrodes. Warming the preoptic region decreased the rate at which the infra-red heaters were turned on, but the effect was not as obvious as the increases observed during cooling.4. Pigs placed in a cold or neutral environment did not learn to push a switch in order to obtain radio frequency heating of the preoptic region.

Animals↗
PubMedDate not supplied

Gardnerella vaginalis infection and sexual contact in female children.

Gardnerella vaginalis (GV) infection has been reported as being acquired via sexual contact in adults and as an indicator of sexual contact in female children (DeJong, 1985). The purpose of this study was to determine if GV infection was more commonly found in 191 female children who gave a history of sexual contact and/or were infected with Neisseria gonorrhoeae (GC) or Chlamydia trachomatis (CT) (Group 1), compared with 144 female children evaluated for possible sexual abuse and found to have no such history or infection with GC or CT (Group 2), or 31 female children (friends of the authors) without such a history or GC or CT infection (Group 3). Vaginal GV was found in 5.3% of Group 1, 4.9% of Group 2 and 6.4% of Group 3 (p > .05). Also, vaginal GV infection was not related to the type of sexual contact or race, but did increase with age in white female children. Because vaginal GV infection is not more commonly found in children with a history of sexual contact than those without such a history, the finding of GV in a vaginal culture in an individual case would not be a reliable marker of sexual contact. Routine culturing for GV is not recommended as part of a sexual abuse workup.

Age Factors↗