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Biomedical subjects

D Parker

Publications and source records attributed to D Parker.

At least 343 records · Page 19Linked to original sources
PubMed1976

Polycythaemia.

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Humans↗
PubMed1976

Central and peripheral action of suppressor cells in contact sensitivity in the guinea-pig.

Suppressor cells were demonstrated in the spleen of guinea-pigs made specifically unresponsive to dinitrofluorobenzene (DNFB) with dinitrobenzene sulphonic acid (DNBSO3). Transfusion of these cells at the same time as sensitization with DNFB, produced a significant reduction in the immunoblasts proliferating in the draining lymph node 4 days later. Transfusion on the day of skin testing produced no greater suppression of skin reactivity than cells taken from animals made hypo-reactive to DNFB by contact with dinitrothiocyanate benzene (DNTB). It is concluded that there are at least two sites that suppressor cells can act. In the case of total unresponsiveness induced by DNBSO3, action is both central and in the periphery. In the case of hyporeactivity induced by DNTB, in which there is no defect in proliferation of T cells in response to antigen, the action of these cells is confined to the periphery. results of spleen weight studies suggest that suppressor cells homing in the spleen respond by proliferation to epicutaneously applied DNFB.

Animals↗
PubMed1976

Continuous monitoring of arterial oxygen tension using a catheter-tip polarographic electrode in infants.

An oxygen electrode mounted in the tip of an umbilical artery catheter was used in 36 newborn infants with severe respiratory illnesses, 28 of whom survived. Thirty-seven electrodes were used. The median age at insertion was 4 hours (range, 30 minutes to 122 hours). Three electrodes failed to work and they were removed or replaced, and two could not be properly evaluated. Thirty-two electrodes functioned satisfactorily for 10 to 190 hours (mean, 75 hours) after a one-point calibration against blood sampled through the catheter. Twenty-two did not need recalibrating before they were removed after 10 to 190 hours (mean, 88 hours. Four of the remaining ten electrodes were recalibrated once after 33 to 97 hours and then functioned until removed 15 to 55 hours later. The other six electrodes failed after 32 to 105 hours (mean, 49 hours). Complications were few. A total of 356 arterial blood samples, obtained after the initial calibration and before any recalibration was necessary, gave a correlation coefficient of 0.93 (P less than .0001) against an independent system for measuring arterial oxygen tension (Pao2) (Radiometer Type E.5046 oxygen electrode). We conclude that the catheter-tip electrode is a safe and reliable instrument for continuously recording Pao2 in newborn infants which much simplifies the management of serious respiratory illnesses.

Arteries↗
PubMed1975

Epicutaneous induction of hyporeactivity in contact sensitization. Demonstration of suppressor cells induced by contact with 2,4-dinitrothiocyanatebenzene.

Partial unresponsiveness to 2,4-dinitrofluorobenzene (DNFB) was produced by the epicutaneous application of 2 per cent 2,4-dinitrothiocyanatebenzene (DNTB) to the dorsum of the ear, 14 and 7 days before sensitization. This state of partial unresponsiveness could be broken by treatment with 300 mg/kg cyclophosphamide (CY) 3 days before the sensitization dose of DNFB. There was a significant increase in the uptake of 125I-labelled iododeoxyuridine in the draining lymph node, 6 days after the application of 2 per cent DNTB and in the contralateral nodes at 4 and 6 days. The state of partial unresponsiveness to DNFB was not associated with a decrease in T-cell proliferation in the draining lymph nodes. The generation of suppressor cells, capable of reacting in the periphery, was demonstrated by passive cell transfer into recipients sensitized to DNFB and depleted of normally produced suppressor cells by pretreatment with CY. These cells were found in spleen and peritoneal exudates of animals treated by the epicutaneous application of 2 per cent DNTB 14 and 7 days previously. It is suggested that the suppressor cells induced by contact with DNTB act by competition with effector cells at the periphery.

Animals↗
PubMed1975

A system for monitoring arterial oxygen tension in sick newborn babies.

The measurement of arterial oxygen tension (PaO2) has for some time now been regarded as an essential part of the management of newborn babies receiving oxygen therapy. A system for monitoring arterial oxygen tension by means of a catheter-tip transducer is described. Comparisons of the transducer output with PO2 obtained by blood sample analysis are discussed. Up to the present time the PaO2 of more than sixty sick newborn babies have been monitored using these transducers in the Neonatal Unit at University College Hospital. The results obtained with these transducers in the first eighteen babies are reported in detail and demonstrate the possibility of continuous, reliable measurement of PaO2 under routine clinical conditions.

Catheterization↗