ABSTRACT
National guidance (executive letter) EL(97)12 stated that population screening should not be provided by the NHS, or be offered to the public until there is effective screening technology for prostate cancer. The study set out to determine the views of general practitioners and, indirectly, their practice staff on prostate cancer screening in primary care upon receiving EL(97)12. This postal questionnaire survey reveals that 81% (95% CI 75% to 87%) of responding general practitioners in North Staffordshire agreed with EL(97)12 and one in ten said that the executive letter changed their views, suggesting that such national guidance has an effect.
Subject(s)
Health Care Surveys , Mass Screening/statistics & numerical data , Prostatic Neoplasms/prevention & control , England , Family Practice , Female , Guidelines as Topic , Humans , Male , Middle Aged , Prostatic Neoplasms/diagnosis , Prostatic Neoplasms/epidemiology , State Medicine , Surveys and QuestionnairesABSTRACT
The authors assessed the ocular toxicity and pharmacokinetics of subconjunctivally and intravenously administered dacarbazine in New Zealand white rabbits. Nine rabbits received a subconjunctival injection of 5 mg (three animals), 10 mg (three animals) or 25 mg (three animals) of dacarbazine in 0.5 mL of sterile water; 10 mg was found to be a well-tolerated dose. This dose was given as a bolus to 42 other rabbits either subconjunctivally (21 animals) or intravenously (21 animals). In both groups the dacarbazine concentrations in the ocular humours, serum and urine were measured by means of high-pressure liquid chromatography at 0.5, 1, 2, 4, 8, 12 and 24 hours, three animals being assessed at each interval. The peak serum levels of the drug were similar with the two routes of administration. The mean peak dacarbazine levels in the aqueous humour and vitreous humour after subconjunctival administration were 250 to 380 times those achieved after intravenous administration. The bioavailability of the drug over 24 hours was 107 micrograms/h.mL in the aqueous and 34 micrograms/h.mL in the vitreous after subconjunctival administration, compared with 0.65 and 0.14 micrograms/h.mL respectively after intravenous administration. Our results provide a solid pharmacokinetic basis for considering subconjunctivally administered dacarbazine in the treatment of human ocular melanoma.
Subject(s)
Conjunctiva/metabolism , Dacarbazine/pharmacokinetics , Animals , Aqueous Humor/metabolism , Chromatography, High Pressure Liquid , Conjunctiva/drug effects , Dacarbazine/toxicity , Injections, Intravenous , Male , Rabbits , Tissue Distribution , Vitreous Body/metabolismABSTRACT
The authors assessed the ocular toxicity and pharmacokinetics of subconjunctivally and intravenously administered cyclosporine in New Zealand white rabbits. Fifteen rabbits received a subconjunctival injection of 5 (five animals), 10 (five animals) or 25 (five animals) mg of cyclosporine in 0.1 mL (intravenous solution of Sandimmune [50 mg/mL]); 5 mg was found to be the maximum tolerable dose. This dose was given as a bolus to 36 other rabbits either subconjunctivally (18 animals) or intravenously (18 animals). In both groups the cyclosporine concentrations in the ocular compartments, blood and urine were measured by means of high-pressure liquid chromatography at 0.5, 1, 2, 4, 8 and 12 hours, three animals being assessed at each interval. Subconjunctival administration resulted in peak cyclosporine concentrations of 718 ng/mL in the aqueous humour and 1078 ng/mL in the vitreous humour, compared with no detectable levels in the aqueous humour and a peak concentration of 292 ng/mL in the vitreous following intravenous administration. The peak blood cyclosporine levels were 10 times lower after subconjunctival injection than after intravenous injection. The results indicate that subconjunctival administration is superior to intravenous administration in enhancing the ocular absorption of cyclosporine while minimizing systemic exposure in the rabbit.