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Biomedical subjects

D B Adams

Publications and source records attributed to D B Adams.

At least 109 records · Page 6Linked to original sources
PubMed1980

Intestinal lymph and the local antibody and immunoglobulin response to infection by Trichostrongylus colubriformis in sheep.

A local antibody response occurred in the small intestine when immune sheep were challenged with the enteric nematode parasite, Trichostrongylus colubriformis. Incoming infective larvae stimulated the appearance of increased numbers of IgA-containing lymphocytes in intestinal lymph. There were increases in the populations of IgA- and IgG1-containing plasma cells in the lamina propria. This did not occur in regions of the small intestine distant to the habitat of T. colubriformis. Challenge infection in immune animals increased the titre of anti-T. colubriformis haemagglutinating antibody in serum, intestinal lymph, intestinal fluid and extracts of intestinal mucosa. Although immune intestinal lymph contains anti-T. colubriformis antibody of IgA isotype, which is presumably produced in intestinal lamina propria, it failed to transfer passive immunity against the parasite. This result, however, does not exclude the possibility that IgA-antibody responses are important in protective immunity against T. colubriformis.

Animals↗
PubMed1978

Rise in female-initiated sexual activity at ovulation and its suppression by oral contraceptives.

This study was designed to test the hypothesis that women exhibit peaks of sexual activity at ovulation, as would be predicted from estrous effects in animals. Married women who used contraceptive devices other than oral contraceptives experienced a significant increase in their sexual behavior at the time of ovulation. This peak was statistically significant for all female-initiated behavior, including both autosexual and female-initiated heterosexual behavior, but was not present for male-initiated behavior except under certain conditions of contraceptive use. Previous failures to find an ovulatory peak may be due to use of measures of sexual behavior that are primarily determined by initiation of the male partner. Women using oral contraceptives did not show a rise in female-initiated sexual activity at the corresponding time in their menstrual cycles, probably owing to the suppression of ovulatory increases in hormone secretion by the oral contraceptives.

Adult↗
PubMed1978

Flow and protein composition of intestinal lymph in sheep infected with the enteric nematode, Trichostrongylus colubriformis.

A study of immunoglobulin and albumin concentrations and the flow of intestinal lymph was made in sheep during infection with the parasitic nematode, Trichostrongylus colubriformis. Observations were made on uninfected worm-free sheep, on worm-free sheep undergoing primary infection and on immune sheep undergoing challenge infection. The flow of intestinal lymph and the concentrations of IgG1, IgG2 and IgM in intestinal lymph and IgG2 and IgM in blood plasma remained relatively constant during both primary and challenge infection. The concentration of IgA in intestinal lymph and blood plasma increased as early as day 6 of primary infection and maximum values were observed at day 34. By day 34 of primary infection the concentration of IgG1 in blood plasma was significantly greater than that found in worm-free controls. Plasma IgG1 concentrations in resistant sheep were also significantly greater than those observed in worm-free controls. Challenge infection in immune sheep did not raise the concentration of IgA in intestinal lymph and blood or IgG1 in blood. An indirect haemagglutination test was used to detect antibodies to T. colubriformis. Primary infection did not increase anti-worm antibody titres in either intestinal lymph or serum. Significant antibody titres were present in serum and lymph from immune sheep and were rapidly increased by challenge infection. Most antibody activity in serum was associated with IgM, whereas that in intestinal lymph was associated with IgA. These observations indicate the occurrence of a local antibody response to T. colubriformis in the intestine of immune sheep.

Agglutinins↗
PubMed1978

Studies on the role of histamine and 5-hydroxytryptamine in immunity against the nematode Trichostrongylus colubriformis. V. Changes in amine levels in the intestine following infection of guinea pigs of different immune status.

A temporal relationship was established between the onset of expulsion of the parasitic nematode Trichostrongylus colubriformis from the intestine of both vaccinated and adoptively immunized guinea pigs with a sudden increase in small intestinal mucosal histamine to two or three times pre-infection levels. However, in guinea pigs whose capacity to expel T. colubriformis was inhibited by treatment with anti-lymphocyte serum, mucosal histamine remained at pre-infection levels. The results support previous findings which suggest an important role for histamine in the effector mechanism of the immune response of guinea pigs against T. colubriformis.

Animals↗
PubMed1978

Interlaboratory comparisons of nickel analyses in urine by atomic absorption spectrometry.

Two interlaboratory surveys of urine nickel analyses were performed in which eight or nine urine samples were distributed to laboratories in seven nations for measurements of nickel concentrations by atomic absorption spectrometry. In both surveys, wide discrepancies were observed in the values for urine nickel concentrations that were obtained in different laboratories by various analytical methods. This finding documents a serious need for improvement in the proficiency of nickel analyses. Nonetheless, excellent interlaboratory concordance was found in the rankings of urine samples in order of increasing nickel concentrations. Analytical techniques that involved preliminary wet or dry ashing and extration steps before flameless atomic absorption spectrometry were generally superior to techniques for direct analysis of urine by flameless atomic absorption spectrometry in respect to (a) analytical sensitivity, (b) recovery of added nickel, (c) interlaboratory precision, and (d) interlaboratory concordance of ranking of urine samples in order of increasing nickel concentrations.

Evaluation Studies as Topic↗
PubMed1977

Single unit recording in the midbrain of rats during shock-elicited fighting behavior.

Single unit activity was recorded extracellularly from the midbrain of rats during fighting behavior and during non-fighting control manipulations. Fighting behavior was elicited by footshock or startle stimuli or occurred spontaneously as a result of prior footshock presentations. Seven cells were found in the midbrain reticular formation and central gray which displayed maximum firing rates during fighting behavior. These cells also fired to a limited extent to some of the control manipulations, particularly contralateral vibrissae stimulation. These cells fired phasically during fighting behavior and their firing was correlated with either the approach or paw-strike of the opponent animal or to the response of the recording animal to a tactic of the opponent animal. However, no specific movement or sensory event reliably predicted the firing of these cells during fight sequences. Cells located in other midbrain areas, such as the deep tectum or the area of the red nucleus, also responded during fighting behavior. However, the discharge of these cells was correlated with specific body movements or sensory events. The activity during fighting was similar in rate and pattern to activity during control manipulations whenever similar movements or sensory stimulation were produced. Cells were also found which did not discharge during fighting behavior although they fired under a variety of other conditions.

Action Potentials↗
PubMed1977

The effect of thymectomy in guinea pigs on the lymphocyte content of central lymph.

The number of lymphocytes discharged from the mesenteric lymphatic duct was measured over several days of continuous lymph drainage in adult guinea pigs which had been thymectomised at birth or as young adults. The reduced output of lymphocytes during the first few days of lymph drainage from neonatally thymectomised guinea pigs indicated that removal of the thymus at birth produced a deficiency in the mobilizable lymphocyte pool. Adult thymectomy led to a decrease in the mobilizable lymphocyte pool which did not become apparent until 35 days after removal of the thymus. This indicated that the production of lymphocytes by the thymus is important in the guinea pig for maintaining adequate numbers of recirculating lymphocytes during adult life. The concentration of lymphocytes was reduced in the peripheral blood of guinea pigs which had been thymectomised at birth. In female guinea pigs this lymphopenia was accompanied by an increase in the number of lymphocytes bearing Kurloff bodies. The concentration of lymphocytes in bone marrow was not significantly altered following neonatal thymectomy.

Animals↗