The effects of Depo-Medrol preservative on the rabbit visual system.
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Periocular injections of corticosteroids play an important role in the management of various ophthalmologic diseases. The Depo-Medrol vehicle, injected into the vitreous, was shown to be toxic to the lens and to the retina when applied at double strength. The authors examined the effects of Depo-Medrol and one of the components of its vehicle, myristyl-gamma-picolinium chloride (MGP), on the functional integrity of the rabbit visual system. Visual function was assessed objectively from the electroretinogram (ERG) and the visual evoked potential (VEP). The experimental drugs were injected into the vitreous humor of one eye while saline was injected into the fellow eye for control. Depo-Medrol did not produce any measurable effects on the ERG or the VEP. When MGP solutions were injected in concentrations at least twice as large as that in the Depo-Medrol, significant reductions in the light- and dark-adapted ERG responses were seen. The effects of the drug on the ERG responses was seen as early as 3 days postinjection and developed to its maximal level within 1-2 weeks. No ERG recovery was seen over a period of more than 2 months. The VEP, elicited by applying light stimuli to the experimental eye, was characterized by low amplitude and delayed implicit time compared with the response obtained from the control eye. (+info)
Protection of Nitrosomonas europaea colonizing clay minerals from inhibition by nitrapyrin.
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Nitrate production by Nitrosomonas europaea in inorganic liquid medium containing ammonium was limited by reduction in pH. In the presence of montmorillonite and vermiculite, expanding clays with high cation-exchange-capacity (CEC), nitrite yield was increased, ammonia oxidation continued at pH values below those which inhibited growth in the absence of clays and growth was biphasic. The first phase was similar to that in the absence of clays, while the second was characterized by a lower rate of nitrite production. Illite, a non-expanding clay with low CEC, had no significant effect on ammonia oxidation, while oxidation of ammonia-treated vermiculite (ATV) occurred with no significant change in the pH of the medium. ATV, montmorillonite and vermiculite, but not illite, protected cells from inhibition by nitrapyrin at concentrations inhibitory to cells growing in suspended culture. This protection was maintained in ATV homo-ionic to Al3+, but montmorillonite made homo-ionic to Al3+ did not provide protection from inhibition. Attachment of cells to clays with high CEC is therefore advantageous in providing exchange at the clay surface of NH+4 and H+ produced by ammonia oxidation, in reducing pH toxicity, and in protecting cells from inhibition. (+info)
The novel nicotinic receptor antagonist, N,N'-dodecane-1,12-diyl-bis-3-picolinium dibromide (bPiDDB), inhibits nicotine-evoked [(3)H]norepinephrine overflow from rat hippocampal slices.
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A multicentre, observational study of sodium picosulfate and magnesium citrate as a precolonoscopy bowel preparation.
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BACKGROUND: Sodium picosulfate with magnesium citrate (PSMC) has been available as a precolonoscopy bowel preparation in Canada since 2005. A high patient acceptability and preference appears to have contributed to its wide adoption across the country. Despite its frequent use, there are relatively few published studies of this product, especially reports regarding its use in routine clinical practice. Moreover, to date, there have been no Canadian studies of any kind. OBJECTIVE: To conduct a preliminary evaluation of PSMC by prospectively collecting data describing its effectiveness. METHODS: In the present multicentre, observational study, sequential patients used PSMC according to each institution's standard colonoscopy protocol. Differences in bowel cleansing protocols included dose timing, fluid intake, dietary restrictions and administration of bisacodyl. During colonoscopy, preparation quality was rated separately for the right and left sides of the colon. RESULTS: Of the 613 patients entered, 606 were evaluable for efficacy. For the right and left colon, respectively, 93.0% and 96.2% of preparations were rated either 'excellent' or 'adequate'. In the 334 patients who received adjunctive bisacodyl and the 272 patients who did not, the results were similar: for the right and left colon, 92.3% and 97.1% of those who did not, and 93.4% and 95.7% of those who did receive bisacodyl, respectively, were rated either 'excellent' or 'adequate'. CONCLUSIONS: Despite the differences in bowel cleansing protocols used at each hospital (including an additional laxative), PSMC consistently yielded a high percentage of positive ratings for efficacy. (+info)
Preclinical antitumor activity of penclomedine in mice: cross-resistance, schedule dependence, and oral activity against tumor xenografts in brain.
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Penclomedine is 3,5-dichloro-2,4-dimethoxy-6-(trichloromethyl)pyridine (NSC 338720), an alpha-picoline derivative with p.o. antitumor activity in preclinical leukemia and solid tumor models. Described here are an in vivo cross-resistance profile of penclomedine, treatment schedule dependence studies, and studies exploring the effects of p.o. drug on human tumors xenografted into mouse brain. The latter studies exploited the apparent facile distribution of penclomedine to the central nervous system. Tumor models used included murine leukemia lines selected in vivo for acquired resistance to various antitumor drugs and the human mammary and lung tumor xenografts MX-1 and H82, respectively. The therapeutic effects of p.o. penclomedine against s.c. MX-1 and H82 xenografts were shown to be independent of treatment schedule. Therapeutic activity was comparable when p.o. and parenteral treatments were compared. Lines of P388 leukemia resistant to melphalan, cyclophosphamide, and carmustine were cross-resistant to penclomedine in vivo. Leukemia lines resistant to antimetabolites, DNA binders/intercalators, and vincristine were not cross-resistant to penclomedine. Intracerebrally implanted MX-1 xenografts retained their sensitivity to p.o. penclomedine, and therapeutic activity was at least comparable to that of carmustine, a drug known for its ability to cross the blood-brain barrier. These results demonstrate attributes of penclomedine that are relatively uncommon among currently available antitumor drugs and that are of interest for the anticipated clinical development of this drug. (+info)