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Biomedical subjects

D B Adams

Publications and source records attributed to D B Adams.

At least 127 records · Page 7Linked to original sources
PubMed1977

Cellular changes in the intestinal lymph of sheep infected with the enteric nematode, Trichostrongylus colubriformis.

Some changes produced in the cell populations of intestinal lymph by infection with the enteric nematode, Trichostrongylus colubriformis, were studied in sheep regularly re-infused with all discharged lymph. Lymphocyte traffic through the intestinal lymphatic duct was reduced until day 35 of primary infection, mainly due to the absence of lymphocytes with smaller cell volumes, but was increased two-fold after day 70 and in immune sheep. Antigen-reactive lymphocytes in blood and lymph were assayed by the uptake of 3H-thymidine in cell culture stimulated by extracts from the larvae of T. colubriformis. Cells from the blood and lymph of immune sheep were highly reactive to worm antigen. A relatively smaller reactivity was present in the blood of worm-free sheep and was abolished during the first 12 days of primary infection. Antigen reactive cells were not detected in intestinal lymph until 12 days after primary infection, and in vitro antigen reactivity in intestinal lymph of immune sheep was increased after challenge with infective larvae. Responses to the mitogens, concanvalin A and phytohaemagglutinin, in cultures of cells from both intestinal lymph and blood were depressed on days 7 and 12 of primary infection. It is proposed that the diminished traffic of lymphocytes in intestinal lymph and the reduced numbers of mitogen and nematode antigen-reactive lymphocytes in both blood and intestinal lymph during the early stages of infection with T. colubriformis is closely related to the slow development of protective immunity to this parasite.

Animals↗
PubMed1975

Cognitive and hormonal factors accecting coital frequency.

Sexual behavior of female undergraduates was assessed by daily questionnaries. Of the 24 subjects, 13 were taking oral contraceptives ("pill" subjects) and 11 were using other methods of birth control ("nonpill" subjects), primarily diaphragm or male prophylactic methods. Three main results were obtained: (1) Intercourse rates were lowest during menstruation and highest immediately following menstruation. (2) Self-rated sexual arousal on a given day correlated with the type of heterosexual encouters on that day rather than with period of the menstrual cycle. (3) Pill subjects reported intercourse on more days than nonpill subjects but reported a lower number of intercourse sessions on day with intercourse than nonpill subjects. These results are interpreted within a general framework of sexual behavior which recognizes the sexual behavior of humans as primarily influenced by cultural and cognitive factors. The possibility is discussed that female sexual behavior might also be found to be affected by hormones if more sensitive measures were used.

Adolescent↗
PubMed1975

Competitive fighting in the rat.

Competitive fighting was obtained in pairs of like-sexed laboratory rats by placing a single piece of food into the food hopper following 48 hr. of food deprivation. The fighting was characterized by offensive sideways posture, full aggressive posture, and bite and kick attack. Tests were conducted at 110-120 days of age on pairs of animals that had been housed together since weaning. Fighting was more frequent in pairs consisting of nonlittermates than in pairs of littermates, and it was equally frequent in male and female pairings. Probability of fighting was enhanced by prior experience with food deprivation, and attack was most often initiated by the heavier animal of the pair.

Aggression↗
PubMed1971

Relation of cardiovascular changes in fighting to emotion and exercise.

1. To obtain evidence on the relative importance of exercise and emotion in the cardiovascular changes of fighting in the cat, the changes during fighting were compared with changes during a mild non-emotional exercise (walking on a treadmill at low speed), and during confrontation without fighting (preparation for fighting), an emotional condition accompanied by no or very little motor activity.2. The direction of change of all variables we measured, iliac and mesenteric flows and conductances, total peripheral conductance, heart rate, cardiac output and blood pressure, was similar in both fighting and exercise.3. Some of the cardiovascular manifestations of preparation for fighting were very different from those of motor activity. These were iliac vasoconstriction, a fall in cardiac output, and often a strong bradycardia, all of these changes being in the opposite direction to changes during exercise and fighting.4. It is suggested that the changes during preparation for fighting represent the cardiovascular manifestations of an emotional state, and that during fighting these manifestations are superseded and masked by changes due to motor activity.

Aggression↗