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Biomedical subjects

J Turk

Publications and source records attributed to J Turk.

192 records · Page 11Linked to original sources
PubMed1975

Analogs of bradykinin with restricted conformational freedom.

Three analogs of bradykinin have been synthesized which bear an alpha-methyl group in the place of an alpha proton at position, 4, 5, or 8. Such analogs possess restricted conformational freedom and are of interest for three reasons. (1) They may provide information about the receptor-bound conformation of the peptide. (2) They may provide a route to antagonists of the native peptide. (3) They may be degraded slowly by proteolytic enzymes. None of the analogs described here antagonized the action of bradykinin, but one exhibited tissue specificity and decreased pulmonary inactivation in the rat.

Amino Acid Sequence↗
PubMed1973

A proposal for a standardized system of reporting human lymph node morphology in relation to immunological function.

This memorandum proposes a standardized system of reporting the histology of human lymph nodes based on commonly used simple staining techniques. The purpose is to provide a uniform, internationally acceptable system by which the histological structure of lymph nodes can be correlated with other parameters of immunological status. The proposed protocols are intended to provide information that is not available in conventional written reports that use such terms as ;hyperplasia' or ;nonspecific lymphadenitis'.

Agammaglobulinemia↗
PubMed1972

A proposal for a standardized system of reporting human lymph node morphology in relation to immunological function.

This Memorandum proposes a standardized system of reporting the histology of human lymph nodes based on commonly used simple staining techniques. The purpose is to provide a uniform, internationally acceptable system by which the histological structure of lymph nodes can be correlated with other parameters of immunological status. The proposed protocols are intended to provide information that is not available in conventional written reports, that use such terms as "hyperplasia" or "nonspecific lymphadenitis".

Histiocytes↗
PubMedDate not supplied

Potential interference of cyclobenzaprine and norcyclobenzaprine with HPLC measurement of amitriptyline and nortriptyline: resolution by GC-MS analysis.

Cyclobenzaprine and its major metabolite, norcyclobenzaprine, differ from amitriptyline and nortriptyline only by the presence of a double bond in the cycloheptane ring. Three patients developed sufficient levels of cyclobenzaprine and norcyclobenzaprine because of either rapid or long-term ingestion of cyclobenzaprine to cause positive interferences in both a Syva EMIT assay and a high-performance liquid chromatographic (HPLC) assay for identification and quantitation of tricyclic antidepressants in serum. Cyclobenzaprine coeluted with amitriptyline, and norcyclobenzaprine eluted slightly earlier than, but was poorly resolved from, nortriptyline in this HPLC assay. We found that cyclobenzaprine could be distinguished from amitriptyline and that norcyclobenzaprine could be distinguished from nortriptyline on the basis of gas chromatographic retention times upon gas chromatographic-mass spectrometric analyses after derivatization with trifluoroacetic anhydride. The compounds were also distinguishable by mass spectrometric criteria.

Acetic Anhydrides↗
PubMedDate not supplied

Renal allograft platelet activating factor synthesis during acute cellular rejection.

The aim of this study was to characterize the synthesis and metabolism of platelet activating factor (PAF, 1-0-alkyl-2-0 acetyl-sn3-phosphorylcholine) by renal tissue undergoing acute cellular allograft rejection in the canine model. Kidneys were transplanted into outbred mongrel dogs and allowed to reject without immunosuppressive therapy. Five days after transplantation, all kidneys were non-functional and the tissue was assayed for the capacity to produce various molecular species of PAF and lyso-PAF using physical-chemical (GC/MS), immunologic (RIA) and biologic (platelet aggregation) assays. Renal cortical tissue obtained from rejecting allografts produced more PAF than control tissue by the following factors (GC/MS): 18-fold for C16:0 PAF; 3-fold for Lyso-C16:0 PAF; 2-fold for C18:1 PAF; and 6-fold for C18:0 PAF. The control tissue to which comparisons were made was renal cortex obtained from the native contralateral kidney. Increases in the production of various molecular species of PAF were also observed with renal medullary tissue undergoing acute rejection, although the magnitude of change was less dramatic than with renal cortex. The predominant PAF metabolite produced both by normal and allograft tissue was C16:0 Lyso-PAF. The increased PAF production by renal allograft tissue undergoing rejection was mainly attributable to C16:0 PAF and C16:0 Lyso-PAF, but increased production of both C18:0-PAF and of C18: 1-PAF was also detected. Increased renal allograft PAF production was also confirmed with a competitive binding immunoassay specific for PAF. In addition, when PAF-like material was isolated and purified from renal allograft incubation media and added to washed canine platelets, an intense aggregation response was observed that was abolished with prior alkaline methanolysis of the isolated material. Aggregation responses of similar magnitude were not obtained with PAF-like material isolated from native (non-rejection) renal tissue. In other experiment, incubation media obtained from rejecting renal allografts was found to contain factor which catalyzed hydrolysis of exogenous PAF to Lyso- PAF at twice the rate induced by media obtained from normal renal tissue. In conclusion, this study has identified dramatic increases in production of the biologically active molecular species of PAF by renal allograft tissue undergoing untreated cellular rejection. High levels of biologically inactive Lyso-PAF were also detected, and renal allograft tissue elaborates a factor which catalyzes rapid hydrolysis of PAF.

Animals↗