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Biomedical subjects

H van Herpen

Publications and source records attributed to H van Herpen.

7 recordsLinked to original sources
PubMed1998

Clinical efficacy and safety of propofol or ketamine anaesthesia in dogs premedicated with medetomidine.

Combinations of medetomidine with either propofol or ketamine were compared for the sedation and induction of anaesthesia in dogs undergoing a variety of surgical (60 per cent) and non-surgical (40 per cent) procedures. Eighty-four dogs were used at four sites. Medetomidine was administered intramuscularly at a dose of 1000 micrograms/m2 body surface area 10 to 15 minutes before the induction of anaesthesia by the administration of propofol (n = 44) or ketamine (n = 40) dosed to effect. The dogs became sedated by medetomidine after a mean (sd) time of 6.7 (5.4) minutes, and their heart rates and respiration rates decreased. Sixteen of the dogs suffered an adverse effect, 13 of them vomited. Anaesthesia was induced by the intravenous administration of propofol (2.1 [0.7] mg/kg) or ketamine (3.7 [1.9] mg/kg), and further doses of the anaesthetic were given, depending on the length of the operation, once in 17 per cent, twice in 11 per cent and three or more times in 24 per cent of the cases. The heart rate of the dogs anaesthetised with ketamine was significantly higher than that of the dogs anaesthetised with propofol, but there were no other significant physiological differences. There were 11 adverse side-effects in the ketamine group compared with five in the propofol group and they were generally more severe. The quality of the recovery from anaesthesia was considered to be smooth in 89 per cent of the propofol group but in only 63 per cent of the ketamine group.

Anesthesia↗
PubMed1993

Disturbed release of growth hormone in mature dogs: a comparison with congenital growth hormone deficiency.

An acquired defect in growth hormone secretion in mature dogs has been associated with some forms of generalised alopecia. In an attempt to elucidate the pathogenesis of the disturbance in growth hormone release, the plasma concentrations of growth hormone and insulin-like growth factor I (IGF-I) were measured in two seven-year-old poodles with alopecia and, for comparison, in two young German sheperd dogs with congenital hyposomatotropism (pituitary dwarfism). In the poodles the basal concentrations of growth hormone were low, although often above the detection limit of the assay. The concentrations of IGF-I were in the reference range for healthy poodles. No growth hormone could be detected in the plasma of the German sheperd dogs and the concentrations of IGF-I were very low. Stimulation with clonidine and growth hormone releasing hormone (GHRH) before and after repeated injections of GHRH did not result in significant increases in growth hormone concentrations in plasma. The concentrations of growth hormone in the poodles fluctuated at low levels during the test period. In the German sheperd dogs the levels of growth hormone remained unmeasurable during the stimulation tests. It was concluded that in the two poodles the basal concentrations of growth hormone were sufficient to maintain normal IGF-I concentrations, and thus the release of growth hormone was considered appropriate. Based upon measurements of urinary corticoids and a review of the literature it is suggested that the lack of a growth hormone response to stimulation was due to the enhanced release of somatostatin as a result of mild and fluctuating hyperadrenocorticism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex Hormones↗
PubMed1993

[Occipital dysplasia in a Pomeranian dog].

Occipital dysplasia, a congenital malformation of the foramen magnum, was diagnosed in a 4-year-old Pomeranian dog. The diagnosis was made by clinical and radiographic findings. Caudal displacement of the cerebellum and hydrocephalus were diagnosed postmortem, using a radiographic contrast study of the subarachnoid space.

Animals↗
PubMed1990

Long-lasting epidural sensory blockade by n-butyl p-aminobenzoate in the dog: neurotoxic or local anesthetic effect?

An aqueous suspension of n-butyl p-aminobenzoate (BAB), a highly lipid-soluble congener of benzocaine, was applied epidurally and around ulnar nerves in dogs. The suspension consisted of 10% BAB and 0.025% polysorbate in 0.9% NaCl. Sensory effects were tested by electrical stimulation. Three epidural injections were given, and the dogs were killed after 21 days. The increase in stimulation threshold was comparable to the effect of lidocaine in a concentration between 0.5% and 1%. Increased sensory threshold lasted for days, whereas no long-lasting motor effects were observed. Pathomorphologic changes were found primarily in the dorsal spinal nerve roots, although slight changes were also found in the ventral spinal roots. White matter degeneration was found only in the lumbar dorsal columns. This result suggested Wallerian degeneration in the dorsal spinal nerves and was at variance with recently published data on epidural BAB. No changes were observed in the ulnar nerves. The authors demonstrated that the pathomorphologic changes were induced by the BAB suspension and not by the suspending additive polysorbate 80. It was postulated that the suspension of BAB, which contains particles of a median size of 15 microns, was mainly confined to the dorsal epidural space where neurolytic changes in axons of the dorsal spinal nerve roots and dorsal columns are induced. This may explain the long-lasting sensory effects seen in intractable cancer pain patients after epidural BAB administration. More research is necessary to define the distribution of BAB in nervous tissue after its epidural administration and to better characterize toxicity, neurolytic effects, and regeneration of nervous tissue after BAB administrations.

Analgesia, Epidural↗