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Biomedical subjects

R G Weber

Publications and source records attributed to R G Weber.

5 recordsLinked to original sources

Modified electrosurgical adapters.

BACKGROUND: Allegedly because of concerns over worker safety in removing spent needles from the Bernsco adapter a new, modified Luer-lok adapter has been introduced by the manufacturer. However, the new adapter frequently holds needles too loosely. OBJECTIVE: To introduce a modification of the original adapter design. METHODS: The end to be inserted into the needle hub was hollowed and trisected to allow flexibility of the phalanges. A small hole is drilled in the distal shaft to allow the placement of a spiral wire, allowing a snug fit even in older, well used electrosurgical handles. CONCLUSION: The modified electrosurgical adapter may facilitate needle removal and increase surety of fit with most electrosurgical handles.

Dermatology

Mohs surgery update. Intraoperative presuturing.

During the course of Mohs surgery, the surgeon may be able to predict that the final closure may require tissue expansion or some other extraordinary measure to close a defect on a particular location. Presuturing, the use of stitches to preoperatively stretch donor tissue peripheral to the wound, has been previously advocated to aid in the primary closure of nonMohs tumor removal defects and scalp reduction defects. We describe the anticipatory need for and the use of button bolstered nonabsorbable sutures to stretch or expand the perioperative tissues for final closure. Previously unreported in the literature, we also employ this technique prior to flap closure. This quick and easy manouever following the intermediate and final stages of Mohs surgery has seen great use in the care of some relatively large tumors.

Aged

Autoradiographic visualization of A1 adenosine receptors in rat brain with [3H]8-cyclopentyl-1,3-dipropylxanthine.

A1 adenosine receptors were labeled in rat brain sections with the antagonist [3H]8-cyclopentyl-1,3-dipropylxanthine ([3H]DPCPX) and visualized at the light microscopic level using autoradiography. The specific binding of [3H]DPCPX to the sections showed the pharmacological characteristics of A1 adenosine receptors and was accompanied by very low levels of nonspecific binding. Whereas GTP had no significant effect on [3H]DPCPX binding to rat brain membranes, the addition of 100 microM GTP increased the apparent affinity of [3H]DPCPX to tissue sections fivefold (from 1.83 to 0.35 nM), enhancing it to the affinity measured in membranes. However, GTP altered neither the binding capacity nor the distribution of binding sites in tissue sections. It is suggested that a competitive antagonism with endogenous adenosine explains the lower affinity of [3H]DPCPX in the absence of GTP. The autoradiographic pattern of [3H]DPCPX binding was characteristic for A1 adenosine receptors. Distinct labeling of the different layers of the cerebellar cortex was shown by photomicrographs generated with the coverslip technique. In addition, several fiber tracts were found to be labeled. The high selectivity for A1 adenosine receptors and low nonspecific binding of [3H]DPCPX, the ability to produce high-resolution autoradiograms, together with the fact that the effects of endogenous adenosine can be eliminated by the addition of GTP make [3H]DPCPX a very useful tool in the autoradiographic study of A1 adenosine receptors.

Animals

Autoradiographic visualization of A1-adenosine receptors in brain and peripheral tissues of rat and guinea pig using 125I-HPIA.

A1-adenosine receptors were identified in sections of rat brain and guinea pig kidney with the radioiodinated agonist 125I-N6-p-hydroxyphenylisopropyladenosine (125I-HPIA) using in vitro autoradiography. The affinities of adenosine receptor ligands in competing with 125I-HPIA binding to tissue sections were in good agreement with those found in membranes, and indicate that the binding site represents an A1-adenosine receptor. The distribution of 125I-HPIA binding sites in rat brain sections was similar to the pattern of [3H]N6-cyclohexyladenosine ([3H]CHA) binding sites determined previously, with highest densities in the hippocampus and dentate gyrus, the cerebellar cortex, some thalamic nuclei and certain layers of the cerebral cortex. In the guinea pig kidney 125I-HPIA labelled longitudinal structures in the medulla. This study demonstrates that 125I-HPIA allows the autoradiographic detection of A1 adenosine receptors in the brain and peripheral organs and has the advantage of short exposure times.

Adenosine