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Biomedical subjects

T James

Publications and source records attributed to T James.

At least 73 records · Page 4Linked to original sources
PubMed1993

Tolerance induction to rat islet allografts by intrathymic inoculation of donor spleen cells.

Intrathymic (i.t.) injection of UVB donor spleen cells induces donor-specific unresponsiveness to cardiac and islet allografts in sublethally irradiated recipients in the low-responder Lewis-to-ACI rat combination. This study examined whether unresponsiveness to islet allografts could be achieved following i.t. inoculation of untreated or UVB-irradiated donor SC under the cover of peritransplant immunosuppression with sublethal TBI or ALS in the high-responder combination of WF-to-Lewis rats. The results of this study show that i.t. injection of untreated SC combined with sublethal TBI or ALS led to permanent islet allograft survival in 50% of recipients, while i.t. injection of UVB donor SC combined with sublethal TBI or ALS resulted in indefinite graft survival in 80-100% of recipients. Third-party (BN) islets were rejected normally in this model, confirming donor-specificity of unresponsiveness. Extrathymic inoculation of UVB-treated donor SC by the subcutaneous, intratesticular, or intravenous routes in similarly immunosuppressed animals did not result in any prolongation of islet allograft survival, thus confirming the importance of the thymus in induction of tolerance in this model. The unresponsive recipients that were challenged with 2nd-set allografts 100 days after islet transplantation, permanently accepted donor-type but not third-party (ACI) cardiac allografts, thus proving that recipients are indeed tolerant to donor alloantigens and that such tolerance is donor- and not organ-specific. This study proposes a novel strategy of immunomodulation that may be useful in induction of specific unresponsiveness to organ allografts.

Animals↗
PubMed1992

History of medicine. Paulesco.

Nicolas Constantine Paulesco achieved the unrecognised distinction of proving that an unknown but constituent factor of the pancreas controls the physiological value of the blood-sugar of a normal animal and that its absence is the cause of diabetes mellitus. His research in this particular field of medicine was carried out on dogs and his proof was the culmination of years of experimental work of precursors, colleagues and himself. This great advance, perhaps equivalent in some respect to the discovery of the therapeutic virtue of penicillin, remains unacknowledged. An exposition of the facts attendant upon this neglect follows. The reader is left to draw his or her own conclusion regarding the award of the Nobel Prize for Medicine in 1923.

Diabetes Mellitus↗
PubMed1990

Absence of abundant binding sites for anesthetics in rabbit brain: an in vivo NMR study.

Using magnetic resonance spectroscopy, the authors tested whether cerebral concentrations of inhaled anesthetics do not increase proportionately at inspired concentrations exceeding 3% 1) because anesthetics bind to and saturate specific sites in the brain or 2) because anesthetic-induced depression of ventilation limits the increase in alveolar anesthetic partial pressure. New Zealand White rabbits were anesthetized with methohexital, 70% nitrous oxide, and local infiltration of 1% lidocaine. Cerebral concentrations of anesthetic were determined from 19F spectra acquired with nuclear magnetic resonance (NMR). Inspired, end-tidal, and arterial anesthetic concentrations, and end-tidal and arterial partial pressure of carbon dioxide were measured. Blood/gas partition coefficients were determined and used to convert arterial anesthetic concentration to partial pressures. In seven spontaneously breathing animals, halothane (1%; n = 5) or isoflurane (0.8%; n = 2) was administered at a constant inspired concentration for 20 min; NMR spectra were acquired between 10 and 20 min. Thereafter, the inspired concentration was increased and the process repeated until apnea occurred. Two additional rabbits were anesthetized with isoflurane and studied similarly but with higher inspired concentrations during mechanical ventilation. In spontaneously breathing animals, ventilatory depression occurred, documented by marked increases in PaCO2, and cerebral concentrations of anesthetic did not increase proportionately at inspired concentrations exceeding 3%. In contrast to an absence of a correlation of inspired and cerebral concentrations during spontaneous ventilation, arterial and cerebral concentrations correlated linearly during both spontaneous and mechanical ventilation (R2 greater than 0.969). These results are consistent with depression of ventilation, rather than binding to specific cerebral sites as an explanation for the nonlinear relationship between cerebral and inspired anesthetic concentrations.

Animals↗
PubMed1990

Pepys on pox.

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History, Early Modern 1451-1600↗
PubMed1990

RAIN in Arkansas.

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Acquired Immunodeficiency Syndrome↗
PubMed1989

Neurosis or psychosis?

The management of patients who attend the surgery requesting psychotropic medication is complicated by the inadequate classification of neuroses and the difficulty in distinguishing between neurotic and psychotic depression. Moreover, patients have lives to lead and know that there is treatment available as they have often been given tablets before.

Adult↗
PubMed1987

Effects of bicarbonate on arterial and brain intracellular pH in neonatal rabbits recovering from hypoxic lactic acidosis.

We used 31P spectroscopy to determine whether administration of a neutralizing dose of bicarbonate in rabbits with lactic acidosis caused a paradoxical brain intracellular acidosis. Ten 10- to 16-day-old rabbits were anesthetized with 0.75% halothane/oxygen and their lungs mechanically ventilated. Metabolic acidosis was induced by decreasing PaO2 to 25 to 35 mm Hg for 1 to 2 hours until the base deficit was 10 to 15 mEq/L. Cerebral ischemia was prevented by maintaining arterial blood pressure at +/- 20% of control value with a venous infusion of epinephrine. Hypoxia was then terminated by administration of 100% oxygen, which was continued for the remainder of the study. After 15 minutes 100% oxygen, 5 mEq/kg 4.2% bicarbonate was administered to five animals; 5 minutes later the same dose was repeated. Control rabbits were given equal volumes of saline solution. In all animals, arterial pH decreased from 7.43 +/- 0.06 to 7.25 +/- 0.08 (SE) during hypoxia, and brain intracellular pH from 7.22 +/- 0.06 to 7.09 +/- 0.09 (SE). Both pH values remained low during reoxygenation. Bicarbonate administration normalized arterial pH (7.41 +/- 0.03), whereas treatment with saline solution did not (7.23 +/- 0.01, P less than 0.05). PaCO2 rapidly increased by 10 mm Hg in the bicarbonate group, and remained elevated; it was unaffected by saline solution administration. Brain intracellular pH in the bicarbonate group increased by 0.12 U over 40 minutes, but intracellular pH in the saline solution group decreased 0.05 pH U (P less than 0.05) over the same period. We conclude that administering a total dose of 10 mEq/kg sodium bicarbonate to neonatal rabbits recovering from hypoxic lactic acidosis increases arterial pH, brain intracellular pH, and PaCO2; it does not produce paradoxical intracellular acidosis in the brain.

Acidosis, Lactic↗