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Biomedical subjects

D Parker

Publications and source records attributed to D Parker.

At least 289 records · Page 16Linked to original sources
PubMed1980

The effects of naloxone on methylphenidate-induced mood and behavioral changes: a negative study.

The effects of naloxone on IV methylphenidate-induced mood, behavior, and neurohumoral changes were assessed in eight psychiatric inpatients. While methylphenidate alone produced anticipated changes, the indications for significant naloxone-methylphenidate interactions were minimal. It is speculated that larger doses of naloxone might be required to produce modification of the psychostimulant effects.

Behavior↗
PubMed1980

Preparation of antisera specific for guinea pig B cells.

Heterologous antisera against guinea pig B lymphocytes have been prepared in rabbits. Sera, obtained 1 week after a third injection of cells from a guinea pig leukemic B cell line (L2C), were absorbed with guinea pig and sheep erythrocytes and guinea pig thymocytes. In the presence of complement, selected antisera killed both L2C cells (85%) and B cells from Hartley outbred guinea pigs (85%). Normal rabbit serum kills guinea pig thymocytes and this ability was enhanced in the sera obtained from rabbits immunized with L2C cells. After three absorptions with thymocytes the antisera retained their cytotoxicity for B cells but did not kill guinea pig thymocytes or peripheral T lymphocytes. The antigenic determinants on the L2C cells that simulate anti-B cell activity are unknown but surface membrane immunoglobulins were excluded. The development of methodology for obtaining a potent and specific anti-guinea pig B cell serum should significantly improve the usefulness of guinea pigs as animals for in vitro studies.

Animals↗
PubMed1980

Dissociation between tumour resistance and delayed-type hypersensitivity to tumour-associated antigens in the mouse.

A comparison was made in mice between resistance to growth of a syngeneic methylcholanthrene-induced fibrosarcoma (Meth A) and specific delayed-type hypersensitivity to this tumour. Resistance could be induced in 90% of mice following a single injection of 10(4) Meth A cells. This resistance could be transferred by spleen cells but not serum. Delayed skin reactivity to ultrasonicated Meth A cells was found in both tumour-resistant and tumour-bearing mice and could be passively transferred by spleen cells and serum. These findings suggest a dissociation between tumour resistance and specific delayed-type hypersensitivity. It would appear that, in this system, delayed skin reactivity to Meth A tumour cells is mediated by humoral antibody despite a mononuclear cell infiltrate at 24 and 48 h and that this could be the reason for its lack of correlation with host resistance to tumour growth which is cell-mediated and not transferable by serum.

Animals↗
PubMed1979

Studies on the intracellular segregation of polyribosome-associated messenger ribonucleic acid species in the lactating guinea-pig mammary gland.

1. Free and membrane-bound polyribosomes were isolated and the associated mRNA species characterized by cell-free protein synthesis, RNA-complexity analysis and polyribosome run-off in vitro. 2. Of the recovered polyribosomal RNA 85% was associated with membrane-bound polyribosomes and contained 87--93% of the total milk-protein mRNA species as assessed by cell-free protein synthesis or RNA-complexity analysis. 3. RNA-complexity analysis showed that the abundant (milk-protein mRNA assumed) species constituted 55% of the post-nuclear poly(A)-containing RNA population, the remainder consisting of a moderately abundant population (18%) and a low abundance population (27%). Calculations suggest that each population contained up to 2, 48 and 5000 different species respectively. 4. RNA-complexity analysis of the free polyribosomal poly(A)-containing RNA demonstrated that all the species in the post-nuclear fraction were present, though in different proportions, the abundant, moderately abundant and low-abundance groups representing 38, 30 and 32% of this population. 5. RNA-complexity analysis of the membrane-bound polyribosomal poly(A)-containing RNA revealed a more limited population, 72% consisting of the abundant (milk-protein mRNA) species, and 28% a population of up to 900 RNA species. 6. Polyribosome run-off confirmed that milk-protein mRNA was associated with the membrane-bound and free polyribosomes, but represented only a small fraction of the total protein synthesized by the latter. 7. Comparative analysis of milk proteins synthesized in mRNA-directed cell-free systems, or by run-off of free and of membrane-bound polyribosomes, is consistent with the interpretation that in vivo the initiation of protein synthesis occurs on free polyribosomes, followed by the attachment of a limited population to the endoplasmic reticulum. After attachment, but before completion of peptide synthesis, the detachable N-terminal peptide sequence of one of these(pre-alpha-lactalbumin) is removed. 8. The results are discussed in terms of the mechanisms involved in the intracellular segregation of mRNA species in the lactating guinea-pig mammary gland.

Animals↗
PubMed1979

Naloxone effects on serum growth hormone and prolactin in man.

Endogenous and exogenous opiate-like compounds have been found to cause increased serum growth hormone and prolactin levels in animals, and, in some cases, humans. Naloxone, a relatively specific narcotic antagonist, decreases serum prolactin and growth hormone levels in animals. Naloxone (20 mg IV) did not significantly alter serum prolactin levels and, minimally but not significantly, increased growth hormone levels in humans to whom it was administered.

Growth Hormone↗
PubMed1979

Acute lymphoblastic leukemia with eosinophilia and basophilia.

A boy with acute lymphoblastic leukemia showed cerebrospinal fluid and blood eosinophilia and basophilia. No cause for the eosinophilia or basophilia was identified, but they preceded the appearance of leukemic lymphoblasts in both CSF and blood. The first appearance of basophils and eosinophils in the CSF was associated with acute symptomatology and responded completely to antileukemic therapy. Though treatment with intrathecal drugs reversed major neurological signs, there was evidence of generalized cerebral cortical atrophy. The possible mechanisms responsible for this unusual cellular reaction include: 1) reaction to antileukemic therapy; 2) immunological reaction to the lymphoblasts; 3) ectopic hormone production; 4) common stem cell origin of lymphoblasts, basophils, and eosinophils. The last explanation seems the most likely.

Antineoplastic Agents↗
PubMed1979

Sensitization of guinea pigs to levamisole.

Levamisole, an anti-helminthic drug used also as an immunostimulating agent, has been found to be a potent skin sensitizer in experimental animal models. Sensitization is associated with marked T-lymphocyte proliferation in the draining lymph node. It is suggested that immunostimulation through increase in the T-lymphocyte population could be a function of the strong sensitization induced by this compound.

Animals↗
PubMed1979

Multiple myeloma.

Explore the source record for details and available documents.

Age Factors↗
PubMed1979

Functional recovery from cancer surgery: estimation of expectations.

Level of expected functional recovery from colostomy, laryngectomy and mastectomy was established by the Delphi technique. One hundred fifteen cancer rehabilitation experts responded to 2 rounds of questionnaires and provided their judgments regarding degrees and timing of recovery in 14 functional, physical and psychological areas. Feedback of first round judgments was provided in the second round and 85% agreement was set as the standard for consensus. The mastectomy patient is expected to have the quickest recovery with former level of functioning reached in most areas by 3 months postdischarge. The colostomy patient is expected to be functioning normally in most areas by 6 months postdischarge. The laryngectomy patient is expected to be functioning normally in most areas by 12 months postdischarge. Some functions were judged to have the same rate of recovery for all 3 patient types; for example, the experts agreed that for the 55-year-old patients described in the case abstracts, sexual activities would not reach the preoperative frequency until 12 months postdischarge.

Breast Neoplasms↗
PubMed1979

Continuous comparison of in vitro and in vivo calibrated transcutaneous oxygen tension with arterial oxygen tension in infants.

Transcutaneous PO2 simultaneously recorded by Drager and Radiometer electrodes on the abdominal skin was compared for six-hour periods with aortic PaO2 recorded by a Searle intravascular oxygen electrode. Ten newborn infants with serious respiratory illnesses, six of whom needed mechanical ventilation, were studied. The skin electrodes were heated to 44 degrees C and calibrated first in vitro, and then in vivo against the infant's PaO2. The results showed that 1) after in vivo calibration both skin electrodes gave an accurate estimate of PaO2 for six hours without resiting of the electrodes; 2) the Radiometer electrode gave as satisfactory an estimate of PaO2 after in vitro as after in vivo calibration; 3) the Drager electrode gave a significantly less accurate estimate of PaO2 after in vitro than after in vivo calibration; 4) no evidence suggesting that peripheral vasoconstriction interfered with the accuracy of estimation of PaO2 by the skin electrodes was found.

Arteries↗