Search PubMed⌕ Search

Biomedical subjects

J V Johnson

Publications and source records attributed to J V Johnson.

79 records · Page 5Linked to original sources
PubMedDate not supplied

Bioconjugation of ribonuclease A: a detailed chromatographic and mass spectrometric analysis of chemical modification by a cross-linking reagent.

The modification of ribonuclease A with the heterobifunctional cross-linker, 4-succinimdyloxycarbonyl-methyl-alpha-[2-pyridyldithio]-toluene (SMPT) is described. RNase A has 11 potential sites of modification by the SMPT reagent. Tracking the two-dimensional separation and proteolytic digestion of SMPT-modified RNase A with ESI/FTICR-MS and HPLC/ESI/QIT-MS demonstrates the detailed information about number of SMPT modifications and sites of modification that can be obtained by application of these techniques. Analysis of native and modified RNase A tryptic digests by ESI/FTICR-MS resulted in the identification of the sites of modification. Semiquantitative results of the reactivity of certain lysine residues toward the coupling reagent SMPT are presented. Two sites (lysines 1 and 37) are highly reactive, while three sites (lysines 41, 61, and 104) appear to be unreactive toward SMPT under the conditions used. Experimental results demonstrate that quantitative comparison of relative intensities of peptide sequences of different charge states is not possible. No correlation was found between number of basic residues and sensitivity to detection. Digestion of the modified and unmodified RNase A by subtilisin followed by examination by HPLC/ESI/QIT-MS and MS(n) enabled further investigation of modification on lysines 1 and 7, including modification at the epsilon- and alpha-amino positions on lysine 1.

Amino Acid Sequence↗
PubMedDate not supplied

Prevention of venous complications from intravenous anesthesia.

Vascular complications following the use of intravenous sedative drugs continue to be a problem in dental anesthesia. Etiological factors associated with pain and thrombophlebitis are reviewed. From reports in the literature and clinical experience, venous complications from intravenous sedation may be reduced by utilizing large veins with the dilution of sedative agents in a fast running intravenous infusion. Intravenous lidocaine may be of use to block reflex venospasm and pain.

Anesthesia, Intravenous↗
PubMedDate not supplied

Women, occupation, and risk of cardiovascular morbidity and mortality.

Despite the many investigations of male workers, little is known about cardiovascular risk attributable to occupational class or occupational exposures among women. Results from a previous investigation suggest that the relationship between these factors may be different in women, for whom lack of workplace social support may be important in cardiovascular morbidity. The finding that women in blue-collar occupations had over three times the rate of coronary heart disease compared with their white-collar equivalents is intriguing. Modest and inconclusive data about the relationship between occupational stress and health status in women suggest that class and level of control may be of importance in women's experience of occupational stress.

Aged↗
PubMedDate not supplied

Comparison of two methods for INR determination in a pharmacist-based oral anticoagulation clinic.

Warfarin is a commonly used oral anticoagulant that is usually initiated after the definitive diagnosis of a certain thromboembolic disorder or disease. Warfarin therapy will usually be prescribed for 6-12 weeks or more, and some patients may continue therapy throughout life, depending on the type of thromboembolic disorder. Major problems associated with warfarin therapy include adverse effects such as bleeding complications and drug-drug or drug-food interactions. In addition, thromboembolic complications may occur due to subtherapeutic dosages of warfarin. The laboratory reference standards for monitoring warfarin therapy are the prothrombin time (PT) and the International Normalized Ratio (INR). While both the PT or INR will reflect the clinical response in the patient, results reported as INR values have been shown to be more accurate than those reported as PT values. Thirty-two patients were enrolled in this study. Our objectives were to compare INR values measured by both the Coumatrak and conventional laboratory method, and to demonstrate the effects of pharmacist intervention on managing patients receiving warfarin therapy. Results from our study reveal that INR monitoring by Coumatrak is similar to the conventional laboratory method. In addition, our study indicates that patients receiving warfarin therapy can be monitored and managed effectively by pharmacists.

Aged↗