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Biomedical subjects

R Lowe

Publications and source records attributed to R Lowe.

At least 37 records · Page 2Linked to original sources
PubMed1990

The human lung fibroblast cell line, MRC-5, produces multiple factors involved with megakaryocytopoiesis.

The human lung fibroblast cell line MRC-5 constitutively produces a megakaryocyte potentiator activity, identified in murine bone marrow liquid culture assays for acetylcholinesterase and megakaryocyte colony assays in the presence of low concentrations of IL-3. The production levels of this activity were increased after stimulation with the phorbol ester analog, mezerein, and the calcium ionophore, A23187. Complete purification of a protein having this activity from conditioned media of induced MRC-5 cells was achieved using gel filtration and ion exchange chromatography. The first 14 residues of the purified protein identified by amino-terminal sequencing were identical to the first 14 residues of IL-6. Recombinant human IL-6 was tested and found to promote megakaryocyte growth. IL-1 beta, another component detected in MRC-5 conditioned media, was unable to promote megakaryocyte colony formation but did reduce the concentration of IL-6 necessary to support megakaryocyte colony formation. Immunoprecipitation using rabbit antiserum prepared against IL-6 removed the megakaryocyte growth activity found in MRC-5 conditioned media. Thus, connective tissue cells such as fibroblasts in the bone marrow may co-stimulate thrombocytopoiesis via IL-6 and, possibly, via IL-1 production.

Acetylcholinesterase↗
PubMed1990

In vivo dehydration of disposable (Acuvue) contact lenses.

The in vivo dehydration of the Acuvue disposable contact lens was measured in six subjects using a contact lens refractometer. On average, the lenses dehydrated 6.2 +/- 1.9% after 20 min and 10.2 +/- 3.9% after 6 h of wear. The magnitude of dehydration is greater than has been reported for other hydrogel lens types of similar water content. This information may assist practitioners in the interpretation of clinical signs pertaining to lens behavior and associated patient symptoms.

Adult↗
PubMed1988

Preoperative percutaneous intraluminal balloon catheter control of major arterial hemorrhage.

Preoperative percutaneous balloon catheter control of major arterial hemorrhage is a useful technique when the damaged vessel is difficult or dangerous to expose. We report two cases, one with a gunshot wound to the internal carotid artery and one with a ruptured splenic artery aneurysm, in whom this approach was successfully employed to stop hemorrhage, control shock, and allow a precise, controlled vascular exposure and repair.

Adult↗
PubMed1988

Benefit of external carotid endarterectomy in patients with advanced cerebrovascular disease.

The external carotid artery and its branches may serve as critical collateral pathways to the cerebral hemisphere when the internal carotid artery is occluded. In this setting, a stenotic lesion of the external carotid artery can result in hypoperfusion as well as lead to embolic phenomena via enlarged collaterals. This is a report of an experience with six external carotid endarterectomies in five patients from April 1983 to March 1986. All five of the patients had an internal carotid artery occlusion ipsilateral to a significant external carotid artery stenosis. Each patient had symptomatic cerebrovascular insufficiency with four of the five patients demonstrating clear cut symptoms, which lateralized to the side with external carotid stenosis and internal carotid occlusion. These symptoms included amaurosis fugax in four patients and transient extremity weakness in two patients. Four out of five patients were completely relieved of their symptoms after external carotid endarterectomy with follow up periods ranging from 6 months to 2 and one half years. There were no perioperative neurological deficits or complications. The duplex scan was useful in identifying possible candidates for this operation. Important technical details include use of an arterial shunt and closure of the internal carotid artery stump, which may be a source of further emboli. It is concluded that with appropriate patient selection, external carotid endarterectomy can be safely employed with gratifying results in patients with advanced cerebrovascular disease.

Aged↗
PubMed1987

Quality care and cost-effectiveness. An organized approach to problem solving.

The reflexive approach to rising hospital costs and decreased revenue is to balance the budget by curtailing expenses. This places budgetary limitations on personnel, supplies, and equipment and ultimately has an impact on the quality of care. An alternative approach is to modify traditional practice patterns so that quality is preserved and costs are reduced. We reviewed elective class I and II coronary artery bypass graft surgery on a cost basis to identify potential problems. High costs in blood and blood-product usage were identified. An in-depth analysis of practice patterns was conducted, and comparisons were made between data from our hospital and other institutions. Modifications that improved quality and reduced costs were designed. Blood and blood-product usage was reduced from an average of 9.2 U to 3.4 U per case, resulting in an estimated cost avoidance of $111,286 per year. No cost advantage was observed with the use of cell savers, membrane oxygenators, or automated coagulation analysis in these routine short pump run surgeries. Though not cost-effective, the cell saver did allow the salvage of 2 U of blood per case. Mediastinal drainage systems (Sorenson) as well as reeducation regarding the safe, albeit low, hematocrit (no transfusions for hematocrits above 25% [0.25]) were effective in eliminating unnecessary use of potentially dangerous and expensive blood products.

Blood Banks↗
PubMed1987

Dehydration of hydrogel lenses during overnight wear.

We studied the extent of dehydration of hydrogel lenses during overnight wear. Seven subjects used a hand refractometer to measure the water content of five different lenses (Hydron zero-6 (nominal water content 38.6%), -0.50 D; Snoflex 50 (52.5%), -0.50 and + 15.00 D, and Hydron Z-67 (67.5%), -0.50 and + 15.00 D) before and after 7 h of both open- and closed-eye wear. No statistically significant difference was observed in dehydration between open and closed eye lens wear. Thick and thin lenses made of the same material were found to dehydrate to an equal extent. Contrary to expectations, the medium water content Snoflex 50 lenses displayed a greater absolute decrease in water content than the higher water content Hydron Z-67 lenses (p less than 0.01). Factors that may influence the extent of dehydration under open- and closed-eye wearing conditions, and the clinical implications of these results, are discussed.

Adult↗
PubMed1986

Intra-arterial fibrinolytic therapy. Efficacy of streptokinase vs urokinase.

This study is a retrospective comparison of the results in 25 low-dose, intra-arterial streptokinase and 12 low-dose intra-arterial urokinase infusions for thromboembolic disease. Intra-arterial streptokinase was successful in 50% of infusions and was marked by significant abnormalities in the coagulation criteria. There was a high incidence of major and minor bleeding (48% overall), which could be attributed to systemic effects of the drug. Urokinase was successful in 100% of infusions, and showed no significant effects on systemic coagulation criteria. There were also fewer complications during urokinase infusion. The average pharmacy cost for a course of intra-arterial streptokinase was $165, while urokinase cost $1142. Despite the significant difference in expense, the increased efficacy and safety of urokinase make it the preferred agent for intra-arterial infusion. Theoretical reasons for the increased effectiveness of urokinase are discussed.

Adult↗
PubMed1986

Human haptoglobin adsorption by a total internal reflection fluorescence method.

Haptoglobin (Hp) is one of the major protein constituents of plasma. Three different forms are found in the population. The 1-1 and 2-2 forms adsorb similarly onto hydrophobic silica [treated with dimethyl dichlorosilane (DDS)] and onto clean silica, although the affinities on the silica surface are lower at 60 minutes contact time. The two forms desorb differently from silica, but desorb similarly from DDS-silica. Adsorption is less reversible on the hydrophobic surface. Due to its adsorbtion tendencies and its high concentration in plasma, the adsorption of Hp may be important in blood interaction at solid-liquid interfaces.

Adsorption↗
PubMed1986

Pancreatic sonography: enhancement by metoclopramide.

Abdominal sonograms were obtained before and after intravenous metoclopramide administration in 25 patients with a wide variety of abdominal complaints. Visualization of the pancreas was improved by this pharmacologic treatment in 44% of those patients in whom gas obscured the pancreatic bed. There was no improvement when fat was the primary prevention of visualization of the pancreas. There were no significant side effects of metoclopramide administration.

Adipose Tissue↗
PubMed1985

Biologic fate of valves in reversed and nonreversed arterial vein grafts.

The cusps of valve-bearing segments of canine cephalic, femoral, and jugular veins were completely divided and were used in interposition grafts in the femoral and carotid arteries in the nonreversed position. Three control grafts had intact valves in the reversed position, and one control graft in the reversed position had division of the leaflets. Nine grafts were studied up to 2 months postoperatively with gross and microscopic observations. The cusp tissue, which shrinks immediately after complete division, disappears very early in the postoperative period in the reversed and nonreversed positions. Two reversed intact valves were still grossly microscopically normal 5 and 7 weeks postoperatively. The complete disappearance of the divided valve with a nonreversed coronary graft 101/2 months postoperatively has been documented at autopsy for the first time in a human subject. The significance of these findings and the superiority of the valveless nonreversed autogenous vein graft in clinical cardiovascular surgery has been discussed.

Animals↗