Publications by authors named "Jasheway D"

Objective: Describe the pharmacokinetics of ciprofloxacin and dexamethasone after administration of CIPRODEX Otic Suspension (CIP/DEX) into the middle ears of children.

Design: Open-label, single-dose, pharmacokinetic studies, administering four drops of CIP/DEX instilled into each middle ear through the tympanostomy tubes immediately following tube placement. Blood was collected for 6h and analyzed for ciprofloxacin and dexamethasone concentrations using a validated liquid chromatography and tandem mass spectrometry (LC/MS/MS) method.

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Fluoroquinolones provide an important single antibiotic therapy for bacterial keratitis caused by Staphylococcus aureus and numerous gram-negative bacteria, including Pseudomonas aeruginosa. The pharmacokinetics of three ocular fluoroquinolones, norfloxacin (CHIBOXIN, Merck, Sharp & Dohme), ciprofloxacin (CILOXAN, Alcon Laboratories), and ofloxacin (OCUFLOX, Allergan Pharmaceuticals), have been studied in the human eye and in both the normal rabbit eye and rabbit models of keratitis. However, the pharmacokinetics of ciprofloxacin have not been previously studied in the tear film of rabbits.

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Epidermal cells were isolated from adult inbred SENCAR (SSIN) mice and separated by density-gradient centrifugation. The cells were pooled into three fractions shown by previous work to differ in their state of differentiation and proliferative potential. The three fractions were examined for their capacity to metabolize exogenous 14C-arachidonic acid (AA) into prostaglandins (PG) and hydroxyeicosatetraenoic acids (HETE).

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A simple and sensitive high-performance liquid chromatographic (HPLC) method for the analysis of 2-methylsulfonylpyridine (2-MSP) in plasma has been developed. Up to 1 mL of plasma containing 2-MSP and an internal standard was extracted with 3 mL of methylene chloride, usually twice, evaporated to dryness, resuspended in mobile phase, and chromatographed on two 15-cm C8 reversed-phase LC columns in series. The mobile phase was 5% acetonitrile in water with a flow rate of 1 mL/min and ultraviolet detection was at 260 nm.

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The activation of protein kinase C, induction of ornithine decarboxylase (ODC), and hyperplasia have been suggested to be linked, sequential processes resulting from phorbol ester application to mouse skin. However, evidence is presented indicating that these events are not necessarily linked or dependent on one another and that significant differences exist in these responses between phorbol ester promotion sensitive (SSIN) and resistant (C57BL/6J) mice. The epidermis from SSIN mice treated with a single application of 12-O-tetradecanoylphorbol-13-acetate (TPA) displayed a large induction of ODC and a subsequent extensive hyperplasia.

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Murine epidermal cells have previously been shown to produce an oxidant response to the mouse skin tumour promoter 12-O-tetradecanoylphorbol-13-acetate (TPA); however, the cellular source of these oxidants has not been well characterized. The demonstration that phospholipase C also elicits this oxidant response suggests that protein kinase C is the common mediator. In order to pursue this hypothesis, studies using protein kinase C inhibitors were carried out; both the induced oxidant response and the induction of ornithine decarboxylase (ODC), a known protein kinase C mediated event, were studied.

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Exposure of isolated SENCAR mouse epidermal cells to the tumor promoter 12-0-tetradecanoylphorbol-13-acetate (TPA) in vitro resulted in the production of oxidant species detected as chemiluminescence. This oxidant response can be inhibited by superoxide dismutase and copper complexes but not catalase or scavengers of hydroxyl radical or singlet oxygen, suggesting that the oxidant is superoxide anion. Inhibitors of various parts of the arachidonate cascade affect the TPA-induced oxidant response in a manner that corresponds to their effects on in vivo tumor promotion experiments.

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Several responses suggested to be critical components of phorbol ester tumor promotion were compared in 12-O-tetradecanoylphorbol-13-acetate (TPA) promotion-sensitive SSIN and TPA promotion-resistant C57BL/6J mice. SSIN mice treated topically with 2 micrograms of TPA showed extensive hyperplasia accompanied by edema, measured as a 26% increase in water content of the skin. Only a very slight hyperplasia and 7% increased water content occurred after TPA treatment of C57BL/6J mice.

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The F1 progeny of a cross between 12-O-tetradecanoyl-phorbol-13-acetate (TPA) tumor promotion-sensitive SSIN mice and TPA promotion-resistant C57BL/6J mice were found to be sensitive to TPA as a tumor promoter. The tumor response was substantial, with an average of 15 papillomas per mouse and a 100% incidence following initiation with 400 nmol dimethylbenz[a]anthracene and promotion with 6.5 nmol (4 micrograms) TPA.

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Components of human serum can be separated on the basis of differences in relative molecular mass by using size-exclusion "high-performance" liquid chromatography. Lipoproteins in fractions of the eluate can be quantitated by conventional chemical and enzymatic methods. Alternatively, if lipoproteins in the serum are selectively prestained with diformazan dye, the column effluent can be monitored spectrophotometrically at 580 nm, so that only the lipoprotein components of serum are detected.

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