PubMed Health⌕ Search

Biomedical subjects

John J Walsh

Publications and source records attributed to John J Walsh.

5 recordsLinked to original sources
PubMed2004

Ionisation characteristics and elimination rates of some aminoindanones determined by capillary electrophoresis.

Capillary electrophoresis (CE) has emerged as an important tool for evaluating the ionisation characteristics of compounds and their corresponding pKa values. A particular strength of CE in this context is that its relative selectivity allows one to measure the extent of ionisation of materials that are impure. In this study, using CE, we have measured the pKa values of a series of anti-inflammatory aminoindanones, which underwent degradation to indenone during the course of the determination. We subsequently monitored the elimination reactions measuring remaining indanone over the pH range 2.6-10 at constant ionic strength and temperature. The decomposition of the tertiary amino derivatives was especially fast with first-order half-lives of less than 10 min observed at pH 7.4. The resulting sigmoidal pH rate profiles can be accounted for by assuming unimolecular elimination of the protonated (slow) and neutral (fast) forms of the amines. This study provides further support for the use of CE in evaluating amino ionisation especially in cases where degradation might be expected.

Amines↗
PubMed2004

Vascular tumors.

Proliferative conditions involving blood vessels and masses that mimic vascular tumors can present to hand surgeons. Patient age at presentation can range from neonates with congenital tumors to adults with malignancies, such as angiosarcoma. This article reviews three basic categories of vascular tumors in the upper extremity: benign, congenital,and malignant.

Glomus Tumor↗
PubMed2004

Inhibition of acetylcholinesterase by Tea Tree oil.

Pediculosis is a widespread condition reported in schoolchildren. Treatment most commonly involves the physical removal of nits using fine-toothcombs and the chemical treatment of adult lice and eggs with topical preparations. The active constituents of these preparations frequently exert their effects through inhibition of acetylcholinesterase (AChE, EC 3.1.1.7). Increasing resistance to many preparations has led to the search for more effective treatments. Tea Tree oil, otherwise known as Melaleuca oil, has been added to several preparations as an alternative treatment of head lice infestations. In this study two major constituents of Tea Tree oil, 1,8-cineole and terpinen-4-ol, were shown to inhibit acetylcholinesterase at IC50 values (inhibitor concentrations required to give 50% inhibition) of 0.04 and 10.30 mM, respectively. Four samples of Tea Tree oil tested (Tisserand, Body Treats, Main Camp and Irish Health Culture Association Pure Undiluted) showed anticholinesterase activity at IC50 values of 0.05, 0.10, 0.08 and 0.11 microL mL(-1), respectively. The results supported the hypothesis that the insecticidal activity of Tea Tree oil was attributable, in part, to the anticholinesterase activity of Tea Tree oil.

Acetylcholine↗
PubMedDate not supplied

Current status of scapholunate interosseous ligament injuries.

Injuries to the scapholunate complex present the surgeon with both diagnostic and treatment dilemmas. The anatomic features, biomechanical properties, radiographic appearance, and surgical treatment algorithms of this small but structurally and kinematically important joint continue to be refined. A thorough history and physical examination, combined with a radiographic evaluation that can include plain radiographs, tomography, motion studies, arthrography, or MRI, usually will define the nature of the ligament injury. Arthroscopy is considered the gold standard for complete evaluation of scapholunate interosseous ligament injury and often is performed as a first step before repair or reconstruction. Procedures such as carpal fusions or capsulodesis can limit excessive scaphoid motion, promote wrist stability, and potentially prevent arthritis, but advances continue to be made in direct scapholunate interosseous ligament reconstruction. Challenges for the future involve improving noninvasive evaluation, defining the degree of extrinsic ligament injury, and improving direct repair and reconstruction.

Arthroscopy↗