ABSTRACT
A series of (2,3)-methylenepenams were examined with respect to binding to essential penicillin-binding proteins (PBPs) in Escherichia coli and Staphylococcus aureus. The compounds were also examined with respect to their interaction with Streptomyces strain R61 DD-carboxypeptidase. The alpha isomer of (2,3)-methylene penicillin G bound to PBP 3 of E. coli and other enterobacteria at 0.1 to 10 micrograms/ml. The beta isomer bound to PBP 3 at 100 micrograms/ml. Either isomer bound to PBPs 1b and 2 of E. coli only at 100 micrograms/ml. The alpha, but not the beta, isomer also bound to PBP 2 of S. aureus at 0.1 micrograms/ml. Binding studies with radiolabeled compounds indicated the binding to be covalent and revealed no additional binding proteins. (2,3)-Methylenepenams active against E. coli bound to PBP 3 and induced filamentation. The compounds also inhibited Streptomyces strain R61 DD-carboxypeptidase with apparent 50% inhibitory concentrations as low as 10(-7) M. The two (2,3)-methylene penicillin G isomers bound to the enzyme covalently, most likely at the same site as penicillin G since partial proteolysis after binding radiolabeled compounds produced similar peptide patterns. The bound beta isomer was released with a half-time similar to that of penicillin G (70 min at 30 degrees C), while the alpha isomer was released with a longer half-time (13 h at 30 degrees C). With either isomer, the major release product was phenylacetylglycine, suggesting C-5-C-6 cleavage.
Subject(s)
Bacterial Proteins , Carrier Proteins/metabolism , Escherichia coli/metabolism , Hexosyltransferases , Muramoylpentapeptide Carboxypeptidase/metabolism , Penicillins/metabolism , Peptidyl Transferases , Staphylococcus aureus/metabolism , Streptomyces/enzymology , Carboxypeptidases/antagonists & inhibitors , Cephalothin/pharmacology , Chemical Phenomena , Chemistry , Escherichia coli/drug effects , Escherichia coli/ultrastructure , Isomerism , Penicillin-Binding Proteins , Penicillins/pharmacology , Protein BindingSubject(s)
Aging , Dementia/drug therapy , Acetylcholine/deficiency , Aged , Alzheimer Disease/drug therapy , Alzheimer Disease/therapy , Behavior/drug effects , Dementia/diagnosis , Dementia/therapy , Humans , Middle Aged , Neurocognitive Disorders/diagnosis , Neurocognitive Disorders/therapy , Psychotropic Drugs/therapeutic useABSTRACT
Labelled 11-methyl prostaglandins have been prepared via the catalytic tritium reduction of 11-iodomethyl intermediates. Two examples are reported for the preparation of such 11-iodomethyl precursors in which the desired lower side chain is attached in non-radioactive steps. Subsequent tritium hydrogenolysis of the 11-iodomethyl lactones followed by addition of the delta 5 cis-double bond yielded prostaglandins having specific activities of 10-15 Ci/mmol.
Subject(s)
Isotope Labeling/methods , Prostaglandins , Tritium , MethylationABSTRACT
Catalytic tritium reduction of cholest-5-en-23-yne-3beta,25-diol diacetate (VIII) gave cholest-5-ene-3 beta,25-diol diacetate-23,23,24,24-t4 (IX) having a specific activity of 92 Ci/mmol. Bromination, dehydrobromination and hydrolysis of the labelled material gave cholesta-5,7-diene-3beta,25-diol-23,23,24,24-t4 (XI) which was photolyzed to the previtamin and then thermally equilibrated to 25-hydroxycholecalciferol-23,23,24,24-t4 (I).
Subject(s)
Hydroxycholecalciferols/chemical synthesis , Catalysis , Isotope Labeling , Methods , TritiumABSTRACT
A series of analogs of thyroliberin (TRH) ([L-delta3Pro3]-TRH, [D-delta3Pro3]-TRH, [L-3-MeHis2, L-delta3Pro3]-TRH) in which proline was replaced by L- or D-3, 4-dehydroproline was synthesized. The analogs exhibited approximately the same biological activity as the corresponding proline-containing peptides. These analogs and others in which 3, 4-dehydroproline is present at the NH2-terminal, COOH-terminal or internal positions in the peptide were successfully reduced with deuterium or tritium to provide the 3, 4-2H2-proline or 3,4-3H2-proline analogs, respectively, with near theoretical values of substitution. A novel procedure for the chemical resolution of DL-3, 4-dehydroproline is also described.
Subject(s)
Peptides , Animals , Cells, Cultured , Chemical Phenomena , Chemistry , Deuterium , In Vitro Techniques , Peptides/chemical synthesis , Peptides/pharmacology , Proline/analogs & derivatives , Proline/metabolism , Rats , Thyrotropin/analogs & derivatives , Thyrotropin/chemical synthesis , Thyrotropin/metabolism , TritiumABSTRACT
A simple and specific radioimmunoassay was developed for the determination of the anticonvulsant agent clonazepam directly in plasma without extraction. Antibodies to clonazepam were produced in rabbits after immunization with an immunogen prepared by covalently linking the 3-hemisuccinyloxy derivative of clonazepam to bovine serum albumin. When employing 3H-clonazepam as the tracer, the radioimmunoassay has a limit of sensitivity of 5 ng/ml using a 0.1-ml sample of plasma. The antibodies exhibited a high degree of specificity for clonazepam; no cross-reactivity was observed with its 7-amino and 7-acetylamino metabolites nor with a number of other widely prescribed anticonvulsant agents that might be administered in conjuction with clonazepam. Satisfactory agreement was obtained for the plasma levels of clonazepam in humans when samples were assayed by the radioimmunoassay and an established electron-capture GC technique. By virtue ot its simplicity, the radioimmunoassay offers a distinct advantage to the clinician for monitoring plasma clonazepam levels and the compliance of patients undergoing anticonvulsant therapy with the drug.
Subject(s)
Benzodiazepinones/blood , Clonazepam/blood , Animals , Antibody Specificity , Chromatography, Gas , Clonazepam/immunology , Clonazepam/therapeutic use , Humans , Methods , Rabbits/immunology , Radioimmunoassay , Serum Albumin, BovineABSTRACT
A simple, specific, and sensitive radioimmunoassay was developed for the determination of the diuretic bumetanide in plasma and urine. Antiserum to bumetanide was obtained from rabbits immunized with an immunogen prepared by covalently coupling the glycine conjugate of bumetanide to bovine serum albumin. Following extraction of the sample at pH 5.5 with ether, radioimmunoassay of the residue from the ether extract allows for the determination of bumetanide with a limit of sensitivity of about 1 ng/ml using 0.1 ml of plasma or urine. The specificity of the radioimmunoassay was established by comparison with specific radiometric and spectrofluorometric techniques. The pharmacokinetic profile of bumetanide in eight human subjects receiving single 2-mg oral doses of the drug was elucidated using the radioimmunoassay. The peak plasma levels ranged from 39 to 50 ng/ml at 1-4 hr after administration and declined with a mean apparent half-life of 1.17 hr. The mean plasma clearance rate was calculated to be 255 ml/min. During the first 24 hr, a mean of 43% of the bumetanide dose was excreted in the urine as intact drug.
Subject(s)
Bumetanide/analysis , Diuretics/analysis , Adult , Animals , Antibody Formation , Bumetanide/immunology , Bumetanide/metabolism , Cattle , Female , Humans , Kinetics , Male , Methods , Middle Aged , Rabbits/immunology , Radioimmunoassay , Serum Albumin, Bovine , Spectrometry, FluorescenceABSTRACT
The patient with cancer faces a crisis involving many basic questions and major life adjustments. The natural history of the illness may involve progressive loss in the patient's functional capacity, and the patient needs medical, psychologic, and social support. The family of the patient with cancer can provide much help if their potential resources are fully utilized. Conferences involving the patient, family members, and health care professionals allow for open communication, problem-solving, and support for the patient and family through this difficult time. A case is reported illustrating the value of periodic family conferences in the care of a patient with metastatic disease.
