A protective effect against undesirable increase of dihydroetorphine permeation through damaged skin by using pressure-sensitive adhesive tape with an ethylene-vinyl acetate co-polymer membrane.
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The release kinetics of dihydroetorphine (DHE) from pressure-sensitive adhesive (PSA) tape with an ethylene-vinyl acetate co-polymer (EVA) membrane as a diffusion-controlling membrane and its protective effect from an unpredictable increase in skin permeation of DHE caused by stratum corneum damage were investigated. The DHE flux through the EVA membrane was enhanced with the increase of vinyl acetate content. Although the DHE release from the PSA tape was proportional to the square root of the time, the release from the PSA tape covered with the EVA membrane was dominated by zero-order rate. The release rate increased by the addition of isopropyl myristate to the PSA layer, due to the increase of solubility and diffusivity of DHE in the PSA layer, and not a decrease of permeation resistance in the EVA membrane. When using the PSA tape with the EVA membrane, the steady-state flux of DHE through hairless rat skin with stratum corneum damage was not 2-fold more than that through non-damaged skin. Plasma DHE concentration rose promptly above 5 ng/ml after the application of the PSA tape onto the damaged skin in hairless rat. In contrast, when the PSA tape with the EVA membrane was applied onto the damaged or non-damaged skin, plasma concentrations in the both cases were maintained in the therapeutic range (0.2-1.2 ng/ml). These results suggest that the PSA tape with the EVA membrane can be used to protect from the unpredictable increase in skin permeation of DHE due to stratum corneum damage. (+info)
Investigation of interpolymer complexation between Carbopol and various grades of polyvinylpyrrolidone and effects on adhesion strength and swelling properties.
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PURPOSE: To investigate the interpolymer complexation between Carbopol 934P (CP) and various grades of polyvinylpyrrolidone (PVP) (K90, K32, C15, and VA/S-630). METHODS: Amount of fresh and dried CP-PVP complexes, water retaining capacity, apparent density, pH, conductivity, FTIR, swelling and adhesion strength were studied. RESULTS: Interpolymer complexation occurred between CP and all the PVP, but most significantly with PVP K90. Maximum amount of fresh and dried CP-PVP K32 complexes were obtained at a weight ratio of 1:1. On the contrary, CP concentration was linearly related to amount of CP-PVP K90 complexes produced and their water retaining capacity were all above 97%. Increase in CP concentration caused a decrease in pH, but an increase in conductivity for all the CP-PVP complexes. The apparent density of the filtrate of CP-PVP K90 complex was the lowest and its IR spectrum was similar to that of pure PVP K90, indicating that all the CP has interacted with the PVP K90. Discs of physical mixtures of CP-PVP K90 swelled gradually and reached a maximum after 20-30 hr, while discs of solid complex swelled readily and reached a maximum within 20 hr. Adhesion strength was directly correlated to CP content. However, adhesion strength of solid CP-PVP K90 complex was lower than the physical mixture of the pure polymers. CONCLUSION: Interpolymer complexation occurred between CP and PVP but to a different extent for the various grades of PVP. Complexation was most prominent between CP and PVP K90. (+info)
The use of the TDMAC-heparin shunt in replacement of the descending thoracic aorta.
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The use of a flexible polyvinyl tube bonded with tridodecylmethylammonium-heparin (Gott) as a temporary shunt during the resection of lesions of the descending thoracic aorta has proven a safe and simple means of providing adequate circulation to the abdominal viscera and spinal cord. This technique avoids the metabolic consequences of ischemia to the lower body, diminishes left ventricular afterload during aortic clamping, and obviates the requirement for systemic anticoagulation associated with pump bypass. Between September 1970 and October 1974, 24 patients have been operated using the TDMAC shunt. There were two deaths (9%) among the 22 patients undergoing elective resections. Two patients with acutely dissecting and ruptured aneurysms expired. Followup data has been obtained on all patients from one to 46 months postoperative. The ease with which the shunt is inserted and its adaptability to varied clinical and anatomic situations is stressed. We feel that TDMAC-Heparin shunt provides the best method of circulatory support for elective operative procedures on the descending thoracic aorta. (+info)
Tobacco cessation, the dental profession, and the role of dental education.
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This article describes the development of a comprehensive, interdisciplinary, tobacco cessation program based on twenty years of experience at the Indiana University (IU) School of Dentistry. It reviews the relationship between tobacco use and oral health, the nature of nicotine addiction and cessation approaches involving nicotine replacement therapy. In the early 1980s, tobacco control curriculum and cessation guidelines were introduced at the IU School of Dentistry and cooperative efforts initiated with other U.S. and Canadian dental schools. During the past decade, an interdisciplinary Nicotine Dependence Program has been developed to serve outpatients receiving treatment at all hospitals on the IU Medical Center campus. It is hoped that the models described here will be of value to other dental schools developing educational curricula and tobacco control and cessation programs. (+info)
Designing surfaces that kill bacteria on contact.
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Poly(4-vinyl-N-alkylpyridinium bromide) was covalently attached to glass slides to create a surface that kills airborne bacteria on contact. The antibacterial properties were assessed by spraying aqueous suspensions of bacterial cells on the surface, followed by air drying and counting the number of cells remaining viable (i.e., capable of growing colonies). Amino glass slides were acylated with acryloyl chloride, copolymerized with 4-vinylpyridine, and N-alkylated with different alkyl bromides (from propyl to hexadecyl). The resultant surfaces, depending on the alkyl group, were able to kill up to 94 +/- 4% of Staphylococcus aureus cells sprayed on them. A surface alternatively created by attaching poly(4-vinylpyridine) to a glass slide and alkylating it with hexyl bromide killed 94 +/- 3% of the deposited S. aureus cells. On surfaces modified with N-hexylated poly(4-vinylpyridine), the numbers of viable cells of another Gram-positive bacterium, Staphylococcus epidermidis, as well as of the Gram-negative bacteria Pseudomonas aeruginosa and Escherichia coli, dropped more than 100-fold compared with the original amino glass. In contrast, the number of viable bacterial cells did not decline significantly after spraying on such common materials as ceramics, plastics, metals, and wood. (+info)
Interaction of a cationic polymer with negatively charged proteoliposomes.
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Proteoliposomes were prepared by making bilayer vesicles from neutral egg yolk lecithin and negatively charged alpha-chymotrypsin that had been previously stearoylated. Interaction of these proteoliposomes with a cationic polymer, poly-(N-ethyl-4-vinylpryidinium bromide) (PEVP) was examined. For comparison purposes, interaction of PEVP with egg lecithin vesicles containing an anionic phospholipid, cardiolipin, was also examined. Binding of PEVP to both types of vesicles was electrostatic in nature with the polymer manifesting a higher affinity to the cardiolipin relative to the enzyme. PEVP had no effect on the permeability of the bilayer membranes to sodium chloride. On the other hand, PEVP increased the transmembrane permeability of the nonionic anti-tumor drug, doxorubicin. The greater the negatively charged component in the membrane, the greater the PEVP effect. Polycation binding to the vesicles was accompanied by clustering of the stearoylated chymotrypsin (sCT) molecules within the membrane. This protein clustering is most likely responsible for the increase in the doxorubicin permeation. Enzymatic activity of the membrane-associated sCT remained unchanged upon PEVP binding. These findings seem relevant to the effects of polyelectrolytes on cellular membranes. (+info)
The mechanism of action of a single dose of methylprednisolone on acute inflammation in vivo.
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A model system for the study of inflammation in vivo has been developed using the 16-h polyvinyl sponge implant in the rat. This system allows for simultaneous measurement of in vivo chemotaxis, volume of fluid influx, and fluid concentrations of lysosomal and lactic dehydrogenase (LDH) enzymes. In addition, the enzyme content of inflammatory fluid neutrophils may also be determined. A parallel time course of neutrophil and lysosomal enzyme influx into sponge implants was observed. This was characterized by an initial lag phase and a rapid increase between 5 and 16 h. The origin of supernatant LDH and lysosomal enzymes was studied with anti-neutrophil serum to produce agranulocytic rats. Inflammatory fluid in these rats was almost acellular and contained decreased concentrations of beta glucuronidase (-96%) and LDH (-74%). In control rats all of the supernatant beta glucuronidase could be accounted for by cell death and lysis, as estimated from measurements of soluble DNA. Only 15-20% of the LDH activity could be accounted for on the basis of cell lysis. The remainder was derived from neutrophil-mediated injury to connective tissue cells. Large intravascular doses of methylprednisolone markedly inhibited neutrophil influx into sponges and adjacent connective tissue. Secondary to decreased neutrophil influx, fewer neutrophils were available for lysis, and lysosomal enzyme levels in inflammatory fluid decreased. No evidence for intracellular or extracellular stabilization of neutrophil lysosomal granules by methylprenisolone was found. (+info)
Renal artery embolization using a new liquid embolic material obtained by partial hydrolysis of polyvinyl acetate (Embol): initial experience in six patients.
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OBJECTIVE: To evaluate the therapeutic efficacy of a new liquid embolic material, Embol, in embolization of the renal artery. MATERIALS AND METHODS: Embol is a new embolic material obtained by partial hydrolysis of polyvinyl acetate mixed in absolute ethanol and Iopromide 370 and manufactured by Schering Korea, Kyonggido, Korea. Six patients who underwent embolization of the renal artery using Embol were evaluated. Four were male and two were female and their ages ranged from 11 to 70 (mean, 53) years. Clinical and radiologic diagnoses referred for renal artery embolization were renal cell carcinoma (n = 3), renal angiomyolipoma (n = 2) and pseudoaneurysm of the renal artery (n = 1). After selective renal angiography, Embol was injected through various catheters, either with or without a balloon occlusion catheter. Changes in symptoms and blood chemistry which may have been related to renal artery embolization with Embol were analyzed. RESULTS: The six patients showed immediate total occlusion of their renal vascular lesions. One of the three in whom renal cell carcinoma was embolized with Embol underwent radical nephrectomy, and the specimen thus obtained revealed 40% tumor necrosis. In the two patients with angiomyolipomas, the tumors decreased in size and abdominal pain subsided. Bleeding from pseudoaneurysm of the renal artery was successfully controlled. Four patients showed symptoms of post-embolization syndrome, and one of these also showed increased levels of blood urea nitrogen and creatinine. One patient experienced transient hypertension. CONCLUSION: Embol is easy to use, its radiopacity is adequate and it is a safe and effective embolic material which provides immediate and total occlusion of renal vascular lesions. (+info)