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Biomedical subjects

T Collins

Publications and source records attributed to T Collins.

At least 181 records · Page 10Linked to original sources
PubMed1982

Making videotapes: an activity for hospitalized adolescents.

An activities specialist, an instructional technologist, and an occupational therapist developed a videotape program for hospitalized adolescents. The goals of the program were to provide clients with an opportunity to use the videotape medium creatively, to promote communication between staff and clients, and to facilitate each client's mastery of some aspect of the health care experience. The program was initially implemented on a 30-bed adolescent inpatient unit of a pediatric hospital. Later, with little modification, the program was implemented with an outpatient adolescent group of 6 developmentally disabled young male adults whose antisocial behavior had resulted in contact with the penal system.

Adolescent↗
PubMed1981

Post-translational cleavage of mucocyst precursors in Tetrahymena.

Pulse-chase experiments utilizing intact Tetrahymena revealed that at least six proteins (molecular weights, 61,000, 56,000, 51,000, 48,000, 42,000, and 38,000) were unstable and underwent proteolytic cleavage during the first 20 min of the chase period. At least 9 product polypeptides (molecular weights, 45,000, 41,000, 25,000, 21,000, 20,000, 18,000, 17,000, 16,000, and 15,000) appeared during the chase. The proposal that the product polypeptides were actually mucocyst constituents was supported by a variety of observations. First, treatment of whole cells in a complete media with dibucaine caused precursor cleavage and product accumulation with kinetics that were consistent with previous morphologic observations on mucocyst formation. Second, the product polypeptides were enriched in a cell fraction containing just cortical components and amorphous material consistent with aggregated mucus. Third, the labeled product polypeptides in the cortex comigrated with partially purified labeled mucus obtained by dibucaine treatment of whole cells. Fourth, one-dimensional peptide mapping of the 45-kilodalton product confirmed that the post-translationally derived product in whole cell pulse-chase experiments was similar to the purified products in the cortex fraction and in dibucaine-released mucus. Two-dimensional peptide mapping of the 125I-labeled tryptic peptides of three pairs of products in the cortex and mucus further suggested a strong homology. The cleavage of mucocyst precursors was blocked by agents which deplete ATP levels and by N-tosyl-L-phenylalanyl chloromethyl ketone. Preliminary structural relationships were established between some of the precursors and products by one-dimensional peptide mapping. Models for the biogenesis of mucocysts are discussed, and it is proposed that the additional sequence information present in the precursors may be required for the intracellular transport of these proteins or their insertion and assembly within the mucocyst.

Animals↗
PubMed1977

Dose response to fenoprofen in an antipyretic study of fenoprofen and propoxyphene.

Single oral doses of 0, 50, 100, and 200 mg (acid equivalents) of fenoprofen calcium provide essentially linear increases in antipyretic activity over a six-hour period in patients with fever due to acute upper respiratory tract infection. During this same time interval, 200 and 400 mg doses apparently had equal efficacy. Single oral doses of 200 and 400 mg propoxyphene napsylate had no significant effect on the fever of patients with acute respiratory tract infections. No significant interaction between propoxyphene and fenoprofen, related to the antipyretic effect of fenoprofen, was demonstrated.

Administration, Oral↗
PubMed1976

Membrane perturbation: studies employing a calcium-sensitive dye, arsenazo III, in liposomes.

A metallochromic dye, arsenazo III [2,7-bis-(2-arsonophenylazo)-1,8-dihydroxynaphthalene-3,6-disulfonic acid], has been incorporated into the aquenous interspaces of multilamellar liposomes. multilamellar liposomes. Addition of Ca produced no shift in the absorbance spectrum of dye captured by liposomes, whereas disruption of liposomes by Triton X-100, followed by Ca, produced the spectrum chracteristic of the dye-Ca complex: evidence of latency. Addition of excess ethyleneglycol-bis(beta-aminoethyl ether)-N,N'-tetraacetic acid (EGTA) reversed the spectal shift. Differences between spectra obtained in this sequence yielded dye efflus. To measure Ca efflux, difference spectra (+/-EGTA) were obtained from cationic liposomes containing Ca after detergent lysis (sensitivity less than 10 mmol/ml). Since liposomes were impermeable either to dye or Ca until perturbed, it was possible to test a variety of membrane-active steroids (diethylstilbesterol, deoxycorticosterone, etiocholanolone) for their capacity to provoke dye efflux from liposomes; preincorporation of cortisol stablized liposomes against dye leak. Immunoglobulin-coated liposomes containing dye were taken up by phagocytes of Mustelus canis, and phagocytic vacuoles stained red-purple after ingestions. Liposomes containing the calcium-sensitive dye constitute a simple, accurate means for determining membrane perturbation and Ca fluxes; their uptake by cells or organelles remains to be exploited further.

Animals↗
PubMed1975

A general method for the introduction of enzymes, by means of immunoglobulin-coated liposomes, into lysosomes of deficient cells.

Phagocytes of the smooth dogfish (Mustelus canis) contain no endogenous peroxidase within their lysosomes and constitute models for cells genetically deficient in lysosomal enzymes such as myeloperoxidase. We have obtained uptake of over 50% of exogenous horseradish peroxidase, provided the enzyme is exhibited to cells after incorporation into liposomes coated with heat-aggregated (62 degrees, 10 min), isologous IgM. Trapping of horseradish peroxidase (EC 1.11.1.7) by liposomes was established by chromatographic resolution (Sephadex G-200; Sepharose 2B and 4B) of free enzyme from that associated with liposomes; liposome-associated horseradish peroxidase, together with trapped markers of the aqueous compartment (glucose, CrO4 equals), were excluded, and free enzyme and markers were retained. Enzyme and marker trapping was not electrostatic, varied with the molar ratio of charged membrane components, and was reversed by detergent lysis (Triton X-100) of liposomes. Uptake at 30 degrees of aggregated IgM-coated liposomes containing trapped horseradish peroxidase exceeded that of free enzyme of 100-fold, and was more efficient than uptake of horseradish peroxidase presented in uncoated liposomes or in liposomes coated with native IgM. After phagocytosis, peroxidase-rich liposomes were localized exclusively in lysosomes of the phagocytes by ultrastructural histochemistry; the enzyme displayed over 50% latency to osmotic lysis. This method may prove to be of general use in the provision of exogenous enzymes to phagocytic cells genetically deficient in lysosomal hydrolases.

Animals↗
PubMed1975

Educational attainment in adolescent school phobia.

The educational attainment of 100 school-phobic youngsters was compared to that of 100 other psychiatric patients, using the reading quotient as the main measure. Age and IQ were allowed for. RGs were, on average, higher in the school phobic group than in the other subjects, except in a small number of younger children of high IQ. Additional comparisons with another group of psychiatric patients and with the general population,using regression equations, failed to provide any evidence of poor educational attainment in school phobia.

Achievement↗
PubMed1975

Prediction of post-freshman year dental student performance.

The orientation of the remedial education program was changed as a result of this study. By using freshman achievement to aid in prediction of later performance it was found that inefficient students could be identified much earlier with reliable accuracy (R equal to 0.9). Although the computer program did not produce a reliable formula for the prediction of specific problem disciplines, it allowed a preventive as well as a remedial mechanism to assist the inefficient student.

Education, Dental↗
PubMedDate not supplied

Intracoronary and aortic root myocardial contrast echocardiography: the effect of route, dose, and pharmacologic coronary vasodilation.

Myocardial contrast echocardiography is useful for the assessment of myocardial perfusion but has required direct intracoronary injections. Aortic root myocardial contrast echocardiography has the potential advantage of allowing simultaneous assessment of multiple perfusion beds, as well as evaluating competitive and collateral flows. This study assessed the safety and efficacy of intracoronary and aortic root injections of sonicated 5% human serum albumin (Albunex) with and without concomitant coronary vasodilation. Without vasodilation, 72% of intracoronary injections had optimal myocardial enhancement, compared with 21% of aortic root injections. For individual patients, significant dose-response relationships existed for both intracoronary and aortic root injections, although contrast intensity for a given dose varied between patients. Pharmacologic vasodilation resulted in significant increases in contrast intensity and in the incidence of optimal myocardial contrast after aortic root injections. Aortic root myocardial contrast echocardiography potentially allows the simultaneous assessment of multiple perfusion beds through a route somewhat less invasive than that of direct intracoronary injections.

Adult↗
PubMedDate not supplied

Response forms reflect pharmacists' participation in retrospective DUR.

This study examined pharmacists' responses to two different Medicaid retrospective therapeutic interventions (excessive use of beta 2-agonist inhalers and long-term use of sedatives) in New Mexico. It also examined the types of actions pharmacists reported taking, and the differences between actions taken by physicians and pharmacists in terms of response rate, tone of responses, and time spent responding to the intervention. The most frequent pharmacist action was to call the physician. Response rates for the drug use review (DUR) program were higher for physicians than for pharmacists; pharmacists also took twice as long as physicians to respond to both interventions. The study results indicate a need for better methods to document clinical services performed by pharmacists under the Medicaid DUR program to obtain reimbursement and justify therapeutic decisions. Pharmacists also need documentation methods that are relatively easy to use so that they can respond more quickly to interventions.

Adrenergic beta-Agonists↗
PubMedDate not supplied

Lymphocytes recognize human vascular endothelial and dermal fibroblast Ia antigens induced by recombinant immune interferon.

T-lymphocyte-mediated responses to the cellular components of blood vessels are important in rejection of allografts. The induction of cytolytic T lymphocytes (CTLs) depends on recognition of foreign class II major histocompatibility complex antigens (human HLA-DR, DC/DS, SB and others, collectively referred to as Ia) on the target cells whereas killing by CTLs usually depends on recognition of foreign class I antigens (HLA-A, B), although some alloreactive CTLs recognize foreign Ia instead of HLA-A, B (refs 5-8). The expression of Ia antigens has traditionally been regarded as restricted to immunological cell types, and the presence of class II antigen-bearing 'passenger' leukocytes in rodent organ grafts appears necessary for graft rejection. Recently, Ia antigens have been observed by immunofluorescence microscopy on human renal and dermal capillary endothelium. We have previously shown that human umbilical vein endothelial (HUVE) cells in standard culture conditions do not bear Ia antigens, but may be induced to do so by products of lectin- or alloantigen-activated T lymphocytes. Furthermore, we found that recombinant immune interferon (IFN-gamma), free of other lymphokines, is a potent inducer of Ia expression in HUVE cells. Here we report that IFN-gamma also induces Ia expression on human foreskin capillary endothelial (HFCE) cells, HUVE cells transformed by Simian virus 40 viral DNA (SV-HUVE cells) and human dermal fibroblast (HDF) cells in culture. Further, we present evidence that Ia present on HUVE cells and HDF cells can be functionally recognized by human T cells, resulting in a two-way interaction between T cells and mesenchymal cells that may be important in allograft rejection.

Cells, Cultured↗
PubMedDate not supplied

Cultured human endothelial cells express platelet-derived growth factor B chain: cDNA cloning and structural analysis.

Vascular endothelial cells have a central role in various pathophysiological responses such as acute inflammation, wound healing and atherogenesis. The anatomical position of endothelial cells between blood leukocytes and the surrounding vascular smooth muscle cells or stromal fibroblasts may intensify and focus the effects of released endothelial cell products. Endothelial cells in culture produce a platelet-derived growth factor (PDGF)-like mitogen. PDGF purified from platelets is a basic protein with an apparent relative molecular mass (Mr) of approximately 30,000 (reviewed in refs 2, 3) and is believed to comprise two polypeptide chains, PDGF-A and PDGF-B (also referred to as PDGF-1 and PDGF-2; refs 5, 6). Sequence analysis of PDGF B chain has revealed a striking homology with the predicted sequence of p28sis, the transforming protein of simian sarcoma virus. sis-Homologous transcripts have been detected by Northern blot analysis of RNA from cultured endothelial cells. However, there are no structural data available on either the protein product or the messenger RNA to establish the identity of the endothelial-derived mitogen with either chain of PDGF. Here we report the isolation and complete sequence analysis of a sis-homologous complementary DNA clone from human endothelial cells, providing an opportunity to study the structure of sis as transcribed by a normal (untransformed) cell. Our results establish that normal human endothelial cells in culture express the B chain of PDGF, and that endothelial-derived PDGF B chain is synthesized as a predicted precursor polypeptide of Mr 27,281.

Base Sequence↗
PubMedDate not supplied

Alternative RNA splicing affects function of encoded platelet-derived growth factor A chain.

Platelet-derived growth factor (PDGF) is a basic protein of relative molecular mass 30,000 (Mr 30K) composed of two polypeptide chains, designated PDGF A and PDGF B. The B-chain is encoded by the c-sis gene, the cellular counterpart of the simian sarcoma virus transforming gene v-sis. The PDGF A-chain cDNA clones recently isolated and sequenced from a transformed human clonal glioma cell line represent at least two alternatively spliced transcript species differing by 69 base pairs at the C-terminus. Here we demonstrate that the normal human umbilical vein endothelial cell (EC) A chain precursor lacks the 15 carboxy-terminal, highly basic amino acids encoded by the larger tumour cell cDNA. Surprisingly, culture media from monkey kidney cells (COS) transfected with the endothelial cDNA clone contained much less mitogenic activity than media from cells transfected with the longer tumour cell-derived A-chain cDNA. This functional difference appeared to be due to inefficient assembly or secretion of the recombinant endothelial-type growth factor. This suggests that some transformed cells may use alternative RNA splicing to modify normal growth factors and by so doing increase the efficiency of mitogen assembly or secretion.

Animals↗
PubMedDate not supplied

Fractured neck of femur.

This article discusses the risk factors associated with fractured neck of femur in older people and outlines the assessments and post-operative care that should be undertaken by nurses.

Femoral Neck Fractures↗