PubMed Health⌕ Search

Biomedical subjects

G M Dorrestein

Publications and source records attributed to G M Dorrestein.

At least 37 records · Page 2Linked to original sources
PubMed1991

The pharmacokinetics of avian therapeutics.

The knowledge of drug disposition and metabolism in various avian species is rapidly expanding. Allometric scaling, as a new method for extrapolating a dose from one species to the other, is a mathematical characterization of the functional consequences of change in mass. Special attention, in addition, has been paid to interspecies differences in relation to metabolic elimination, anatomy, and physiology of the digestive and respiratory systems and differences in drug distribution. Intraspecies differences attributable to physiochemical aspects of the drug preparation and physiologic conditions of the avian patient can also influence drug efficacy. The consequences of the choice of a particular method of drug administration in relation to avian therapy are also considered.

Animals↗
PubMed1990

[A papovavirus-like infection in parakeets].

Several potential causes of disease were detected in young as well as in full-fledged parakeets of several species in an outbreak of disease on a parakeet-breeding farm. Both papovavirus and Absidia sp. were isolated; the drinking water contained a toxic level of nitrates. The pathological findings are presented and the possible role of the various findings in the pathogenesis of the disease complex is discussed.

Animals↗
PubMed1989

[Inventory of the shedding of Chlamydia psittaci by parakeets in the Utrecht area using ELISA].

Using a Chlamydia-ELISA test to detect the agent in cloacal swabs in budgerigars and other parakeets, the following findings may be summarised: --10/25 Breeders of budgerigars (40 per cent) housed birds shedding the agent, involving ten per cent of all birds tested, average shedding being 28 per cent in positive lofts. --4/15 Pet shops (27 per cent) were found to have positive birds on sale, at least three per cent of all tested birds being shedders, the proportion of shedders averaging nine per cent per infected pet shop. --In the flocks of five breeders of psittaciformes, which were known positive flocks from the outset average shedding was eighteen per cent. The test may also be used for detecting the agent in organs. The shedding pattern in known positive birds was apparently decreasing, when a large dose of corticosteroids was administered, shedding recurred. The possibility of a cage bird sanitation scheme is discussed.

Animals↗
PubMed1988

Pharmacotherapeutic aspects of medication of birds.

This review covers current knowledge of the pharmacodynamics and pharmacokinetics of drugs in avian species. Special attention has been paid to inter-species differences in relation to metabolic elimination, anatomy and physiology of the digestive and respiratory system, and differences in drug distribution. Intra-species differences attributable to physicochemical aspects of the drug preparation and physiological conditions of the avian patient can also influence drug efficacy. The consequences of the choice of a particular method of drug administration on pharmacokinetics are also considered.

Animals↗
PubMed1987

Comparative study of ampicillin and amoxycillin after intravenous, intramuscular and oral administration in homing pigeons (Columba livia).

Pharmacokinetics of ampicillin and amoxycillin after intravenous, intramuscular and oral administration was investigated in homing pigeons. The pharmacokinetic parameters in a cross-over study after intravenous administration of the sodium salts were comparable. The only significant difference was found for the distribution phase. The bioavailability after intramuscular injection of the sodium salts was especially low for ampicillin (26 per cent, as against 57 per cent for amoxycillin). The mean peak blood levels at 0.5 hours were 13.65 and 28.80 mg litre-1 for ampicillin and amoxycillin, respectively. After oral administration of trihydrate solutions (8 mg ml-1) the bioavailability was 20 and 35 per cent, respectively, and the mean peak blood levels were 8.46 and 16.98 mg litre-1, found at 1.04 and 1.26 hours. The recovery from the droppings, which include in birds the urine fraction as well, was unexpectedly low. Based on controls for recovery of added penicillin from the droppings and uric acid suspensions, indications were found that the pigeon enzymically inactivates penicillins. The in vitro activity of ampicillin against 266 strains of bacteria isolated from birds was determined. The minimum inhibitory concentration (MIC) for 65.4 per cent of the Escherichia coli was lower than 4 mg litre-1, for 91.1 per cent of the Salmonella species was lower than 2 mg litre-1 and for 100 per cent of the Yersinia pseudotuberculosis was lower than 0.25 mg litre-1. Based on these data and a literature study dosage regimens were calculated for MIC values of 0.5 and 2.5 mg litre-1.

Administration, Oral↗
PubMed1986

Icterus and amaurosis caused by lead poisoning in a cynomolgus monkey (Macaca fascicularis).

The diagnosis and treatment of a case of lead poisoning in a cynomolgus monkey (Macaca fascicularis) are described. The clinical signs were jaundice and amaurosis. Clinicopathological findings suggested cholestasis. A tentative diagnosis of lead poisoning was made when basophilic stippling of erythrocytes was observed in a peripheral blood smear. The diagnosis was confirmed by finding a lead concentration of 2280 micrograms/litre in a venous blood sample. Cage bars painted with red lead appeared to be the source of the poison. The lead was chelated by the intramuscular administration of 2,3 dimercapto-1-propanol (BAL) and calcium disodium edetate for seven days, followed by oral D-penicillamine for five weeks. The encephalopathy was treated with dexamethasone sodium phosphate. Recovery from the blindness was noted after 10 days and marked improvement of the general well being of the animal was observed after one month.

Animals↗
PubMed1986

Bioavailability and pharmacokinetics of ampicillin and amoxycillin from tablets, capsules and long-acting preparations in the homing pigeon (Columba livia).

Three ampicillin and three amoxycillin formulations (tablets and capsules, administered orally, and oily suspensions, injected intramuscularly (i.m.) and subcutaneously (s.c.] were studied in twenty adult homing pigeons (Columba livia). Bioavailability, pharmacokinetics and recovery were determined for each product and administration route. A standard dose of 50 mg/pigeon or 100 mg/kg was used in each study. The mean availability calculated for each of these preparations was 7% for ampicillin anhydrate tablets, 22% for amoxycillin trihydrate tablets, 17% for ampicillin trihydrate capsules, 67% for amoxycillin trihydrate capsules, 46% for ampicillin oily suspension i.m., 67% for amoxycillin oily suspension i.m. and 43% for amoxycillin oily suspension s.c. The blood concentration-time curves for the tablets were very scattered, which was far less the case for the capsules. The maximum blood concentration (Cmax) for amoxycillin was twice as high as for ampicillin. The Cmax resulting from the oily suspensions administered i.m. were low (4.35 +/- 1.05 and 5.04 +/- 1.36 mg/l, for ampicillin and amoxycillin, respectively). The Tmax for ampicillin was 10 h and for amoxycillin it was 0.9 h after administration. Both curves showed biphasic absorption, the initial peak representing an absorption and a distribution phase and the second part reflecting the 'depot-nature' of the drug. After the s.c. administration of the amoxycillin oily suspension the same pattern was found, but the Cmax, which was found at 2.13 +/- 1.03 h after administration, was low (2.81 +/- 0.68 mg/l).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1984

Pharmacokinetic aspects of penicillins, aminoglycosides and chloramphenicol in birds compared to mammals. A review.

Based on a review of the literature, a comparison is made of the pharmacokinetics of penicillins, aminoglycosides, and chloramphenicol in birds and mammals. Penicillins in birds are likely to be more dependent for their elimination on biotransformation than in mammals. Amoxycillin had a relatively low availability (0.34) after p.o. administration. Higher doses (2 to 8 times) were needed to achieve the same peak levels in birds and mammals. Aminoglycosides, which for their elimination largely depend on renal excretion by glomerular filtration, show only minor differences in pharmacokinetics between birds and mammals. Chloramphenicol is mainly excreted after biotransformation and large differences in pharmacokinetic parameters are to be found, not only between birds and mammals, but also between avian species.

Aminoglycosides↗
PubMed1983

Clinical pharmacology and pharmacokinetics of flumequine after intravenous, intramuscular and oral administration in pigeons (Columba livia).

The in-vitro activity of flumequine against 157 strains of bacteria isolated from birds was determined. The minimum inhibitory concentration (MIC) of 96.3% of the Enterobacteriaceae, Proteus spp. and Yersinia pseudotuberculosis studied (n = 135) was less than or equal to 1 microgram/ml. Pharmacokinetics of flumequine in pigeons (Columba livia) was investigated after intravenous, intramuscular and oral administration. From the blood disappearance curves after i.v. bolus injection (10 mg/kg body weight) clearance rate, blood half-time and distribution volume were calculated. The recovery of unchanged flumequine from the droppings in 24 h was 37 +/- 10% of the administered dose. Flumequine was also given i.m. at two dose levels, 10 and 60 mg/kg body weight. The availability of flumequine as intact drug was 22 and 23%, respectively, in 24 h. Therapeutic blood levels were maintained for 4 and 10 h, respectively. After an oral dose of flumequine (60 mg/kg body weight) an availability of 6.7 +/- 2.5% and a peak blood concentration of 2.68 +/- 0.92 microgram/ml at 2 h after administration were found. The recovery of unchanged flumequine from the droppings in 24 h was 1.55 +/- 0.79% of the administered dose. With the exception of the i.m. dose of 10 mg/kg, all flumequine administrations made the pigeons vomit. It appears that blood concentrations below 3 micrograms/ml will not induce vomiting. On the basis of the present data, a dosage regimen for flumequine in pigeons of a priming dose of 30 mg/kg i.m., followed after 8 h by oral administration of 30 mg/kg, this dose being repeated every 8-12 h, would be expected to give blood concentrations between 1.44 and 2.88 micrograms/ml.

Administration, Oral↗
PubMed1982

[A genetic disorder of vitamin A metabolism is recessively white canaries].

A discussion of vitamin A and carotene metabolism in recessively white canaries has been going on for years. This colour canary is reputed to be a 'weak' bird. In the present study, the concentrations of vitamin A, total carotenoid and beta carotene in the serum, liver and feed of both coloured and recessively white canaries were determined. The most important conclusions are: - The normal concentration of vitamin A in the livers of health canaries varies from 500 to 1,500 I.U. of vitamin A per gram of liver. - This is achieved by administering an amount of approximately 15,000 U.U. of vitamin per kg of egg feed. The intake through the feed by each canary will then be approximately 800 I.U. of vitamin A/kg. of body weight daily. - Carotenoids are practically not resorbed from the intestine by recessively white canaries. Vitamin A is also absorbed to a less extent by these birds than it is by canaries which are not recessively white. For their supplies of vitamin A, recessively white canaries are completely dependent on the pressure of vitamin A in the feed. - It would appear to be essential to increase the vitamin A content of the egg feed for recessively white canaries to 20,000 I.U./kg. of egg feed.

Animal Feed↗
PubMed1982

[Tuberculosis in raptorial birds. Clinical cases and differential diagnosis].

Four cases of avian tuberculosis in two goshawks (Accipiter gentilis gentilis), a lanner falcon (Falco biarmicus sp.) and a kestrel (Falco tinnunculus tinnunculus) are reported. All birds, except for the kestrel, were affected with generalized tuberculosis. Clinically, the lanner falcon and kestrel showed lameness due to tuberculous arthritis of a knee joint. One of the goshawks died suddenly. On post-mortem examination, the bird was found to be emaciated, and there was involvement of one knee joint. The other goshawk showed convulsive seizures for three weeks before she died. Histological examination revealed tuberculous meningitis and encephalitis. The diagnosis was based on the detection of acid-fast organisms in every case and was verified in three cases by cultures of the causative organism. Tuberculosis should be considered in the differential diagnosis of emaciation, lameness, arthritis, skin lesions, convulsions and frounce in raptors.

Animals↗
PubMed1980

[Problems arising from disease during the periods of breeding and rearing canaries and other aviary birds (author's transl)].

The hygienic aspects of the various breeding systems are reviewed. The companion aviary is the least hygienic system; the birds are hardest to supervise in this case. Breeding in pairs is preferable from either point of view. Hygiene in aviaries is determined by all component parts of the cage, which are used in keeping the birds. The walls should be smooth and clean. The most hygienic drinking water supply is ensured by bottle-type nipple drinkers provided with a small ball. Feeders should be emptied, cleansed and filled with fresh water every day. A hygienic, dry floor-covering will prevent the appearance of large numbers of Enterobacteriaceae (as well as E. coli) in the intestine. The feed should preferably be given in measured rations. An adult canary should be fed 4 g. of seed and 1 g. of soft feed (containing 20 per cent of protein and 1 per cent of lysine) daily. Causes of death in young birds may be: inferior soft feed, a faulty diet, the presence of pentachlorophenol in the nesting material, infestation with chicken lice (Dermanyssus gallinae), diarrhoea due to a polluted environment (neonatal diarrhoea shortly after hatching), cochlosomosis, drumsticks and atoxoplasmosis. The clinical features and treatment of infectious diseases are discussed.

Animal Feed↗
PubMed1979

[Pentachlorophenol poisoning in nestlings of canaries (Serinus canarius) (author's transl)].

Using binder twine of bales of straw as nesting material for canaries apparently resulted in a reduction of hatchability. However, the outstanding feature was the high mortality rate during the first week after hatching, with a peak on the fourth day and nestlings never growing any older than three months. Other symptoms consisted in marked retardation of growth and poor growth of feathers. The adult birds presented a normal appearance. The most likely cause was the presence of pentachlorophenol (PCP) averaging 285 ppm).

Animals↗