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Biomedical subjects

D G Parsons

Publications and source records attributed to D G Parsons.

At least 19 recordsLinked to original sources
PubMed1993

Comparison of apraclonidine and timolol in chronic open-angle glaucoma. A three-month study.

PURPOSE: To compare the safety and efficacy of apraclonidine ophthalmic solution 0.25% and 0.5% (both given 3 times daily) to timolol maleate (0.5%) given twice daily, in primary open-angle glaucoma or ocular hypertension. METHODS: This study was a 90-day prospective, multicenter, double-masked, randomized, parallel group trial. Intraocular pressure (IOP) measurements were made between 8:00 and 10:00 AM before the morning dose (i.e., up to 12 hours after the evening dose of glaucoma medication) and at 4:00 PM (i.e., 8 hours after the morning dose of glaucoma medication). Patients with off-therapy IOP of greater than 22 mmHg and less than 35 mmHg were entered into the study and were assessed 14, 30, and 90 days after treatment. RESULTS: Sixty-nine patients were enrolled; there were no significant demographic differences among the three study groups. All three treatments significantly reduced IOP over 90 days (P < 0.011). For apraclonidine 0.5%, IOP reductions from 25.8 +/- 3.2 mmHg (pretreatment) to 20.4 +/- 4.00 mmHg (day 90) were observed; for apraclonidine 0.25%, from 25.7 +/- 3.05 mmHg (pretreatment) to 22.1 +/- 4.24 mmHg (day 90); and for timolol 0.5% from 26.1 +/- 3.79 mmHg to 21.1 +/- 5.91 mmHg (day 90). The 90-day period of therapy was completed by 12 patients treated with apraclonidine 0.5%, 21 patients treated with apraclonidine 0.25%, and 23 patients treated with timolol 0.5%. There were no serious adverse events. Fourteen of 22 patients (0.5% apraclonidine) and 21 of 23 patients (0.25% apraclonidine) tolerated the drug well; ocular allergy developed in the remaining patients treated with apraclonidine, which resolved upon discontinuation. CONCLUSIONS: Apraclonidine effectively lowers IOP associated with open-angle glaucoma or ocular hypertension; these pilot results will need to be confirmed by a larger pivotal study. Long-term therapy for some patients may be inhibited by ocular allergy for which there was a higher incidence to the 0.5% apraclonidine solution than to the 0.25% solution in this study. Apraclonidine may be of value as an additional therapy for open-angle glaucoma in selected patients.

Adult↗
PubMed1992

Patient-controlled lumbar epidural fentanyl compared with patient-controlled intravenous fentanyl for post-thoracotomy pain.

Thirty-four patients undergoing thoracotomy were entered into a randomized, double-blind, placebo-controlled study to compare the effects of patient-controlled, lumbar epidural (PCA-E) fentanyl with patient-controlled intravenous (PCA-i.v.) fentanyl with respect to drug requirements, analgesic efficacy and respiratory function. Prior to chest closure patients received fentanyl 2 micrograms.kg-1 by the epidural or i.v. route. In the recovery room further doses of epidural or i.v. fentanyl, 50 micrograms, were administered by the patients who controlled two PCA pumps. Background fentanyl infusion rates were increased by 10 micrograms.hr-1 each time the patient administered a drug bolus and were decreased by 10 micrograms.hr-1 whenever visual analogue scale (VAS) pain scores were less than 2 on a maximum 10 scale. Twenty-nine patients completed the study. Patients in the PCA-E group (n = 14) required less total fentanyl than those in the PCA-i.v. (n = 15) group (1857 +/- 693 micrograms vs 2573 +/- 890 micrograms respectively, P less than 0.05). Fentanyl infusion rates were lower in the PCA-E group at most measurement times. There were no differences between groups in respiratory rates, PaCO2, VAS pain scores or changes in pulmonary function as measured by FVC and FEV1. It is concluded that satisfactory patient-controlled analgesia can be achieved with both epidural and i.v. fentanyl after thoracotomy but that fentanyl requirements are less when given via the epidural route. This supports a direct spinal cord site of action for lumbar epidural fentanyl.

Analgesia, Epidural↗
PubMed1986

Buccal nitroglycerin in congestive cardiac failure: a multicentre study.

One-hundred-and-ninety-two elderly patients with symptoms of congestive cardiac failure, despite therapy with diuretics and inotropic agents, received buccal nitroglycerin as additional medication. They were assessed for up to 6 months. Improvements in symptoms and functional classification were apparent within 14 days, and were maintained for the duration of the study.

Administration, Oral↗
PubMed1980

Experimental infection of turkeys with egg drop syndrome 1976 virus and studies on the application of the haemagglutination inhibition test.

Evidence that turkeys can be infected with virus 127 by the combined intranasal and oral route and that the haemagglutination inhibition (HI) test can be used to demonstrate past infection is presented. Experimental infection of turkeys (six weeks old and six months old) with virus 127 did not result in any clinical signs. However, a rapid HI response was detectable one week later and detectable titres were found 28 weeks after infection. No antibody was detected in 392 sera examined from commercial turkey flocks.

Animals↗
PubMed1978

The pathogenicity of four avian influenza viruses for fowls, turkeys and ducks.

Groups of 10 two-week-old chicks, turkey poults and ducklings were each infected by the intranasal route with one of four avian influenza viruses: a/fowl/Germany/34 (Hav 1N))--Rostock, A/FPV/Dutch/27 (Hav 1 Neq 1)--Dutch, A/fowl/Victoria/75 (Hav 1 Neq 1)--Australian, and A/parrot/Ulster/73 (Hav 1 N1)--Ulster. Eight hours after infection 10 birds of the same age and species were placed in contact with each group and allowed to mix. The clinical signs of disease and onset of sickness and death were recorded. Ulster virus was completely avirulent for all birds. Rostock, Dutch and Australian viruses were virulent for fowls and turkeys causing death in all birds with the exception of 3/10 in contact fowls from the Rostock virus group and 2/10 in contact fowls from the Australian virus group. Only Rostock virus caused sicked sickness or death in ducks, 9/10 intranasally infected and 6/7 in contact birds showed clinical signs and 2/10 intranasally infected and 3/7 in contact ducks died. Intranasal and in contact pathogenicity indices were calculated for each virus in each bird species and indicated quantitatively the differences in virulence of the four virus strains. Virus isolation and immune response studies indicated that surviving in contact fowls in the Rostock virus group had never been infected but that surviving Australian virus in contact fowls had recovered from infection. Infection was not established in Ulster virus in contact fowls and Australian virus intranasally infected and in contact ducks. The birds in all other groups showed positive virus isolations and a high incidence of positive immune response. The last virus isolation was made at 22 days after intranasal infection of ducks with Ulster virus.

Animals↗