PubMed Health⌕ Search

Biomedical subjects

U Karhunen

Publications and source records attributed to U Karhunen.

At least 19 recordsLinked to original sources
PubMed1997

Impaired retinal function in young labrador retriever dogs heterozygous for late onset rod-cone degeneration.

Xenon-flash d.c.-electroretinograms were recorded from dark adapted, rod-cone degenerate homozygote affected (n = 6), heterozygote carrier (n = 3) and control retinas (n = 4) at 3 and 4 months of age, starting at 0.6 log units below control PII threshold. One log unit higher stimuli were necessary to evoke PII in heterozygote and affected retinas compared to controls. Unique to the heterozygotes, double peaked PII responses that were evoked by -2 log relative units intensity stimulation were significantly (P = 0.028) lower in amplitude than those of controls. PII amplitudes of homozygotes were significantly (P = 0.005) lower in amplitude than those of controls at both ages examined in response to -2 and 0 log relative intensity stimulation. No differences were found in scotopic threshold response amplitudes or times to peak between the three groups. Homozygote affected PII times to peak were significantly (P = 0.005) shorter in relation to controls at -2 log units. Findings suggest that heterozygotes exhibit an impaired retinal function which can be demonstrated at 3 and 4 months in this mutant.

Animals↗
PubMed1996

Propofol influences the electroretinogram to a lesser degree than thiopentone.

BACKGROUND: The Electroretinogram (ERG) is used clinically to assess the function of retina. Anaesthetic agents are known to affect ERG, and as anaesthesia is often needed in children and uncooperative patients, knowledge about its effects is of clinical importance. Barbiturates selectively depress ERG components, and we compared thiopentone with propofol to assess if the latter preserved retinal function better. METHODS: Ten pigs, average weight 17 kg (SD +/- 2 kg) were anaesthetized randomly with propofol 10 mg kg-1 or thiopentone 30 mg kg-1. Anaesthesia was maintained by 65% nitrous oxide in oxygen and continuous infusion of the induction agent, i.e. 10 mg kg-1 h-1 of propofol, or 10 mg kg-1 h-1 for the first hour, then 5 mg kg-1 h-1 of thiopentone, with doses being based on pilot studies. After an interval of one week the programme was repeated using the other agent. After 40 minutes dark-adaptation, responses to single flashes of graded intensities from a xenon flashlamp were recorded at five-minute intervals. The a- and b-wave amplitudes and implicit times (time to peak), and a-wave slopes were determined. RESULTS: The b-wave implicit time was significantly shorter during propofol anaesthesia than when using thiopentone. The effect was most pronounced at the lowest intensities (P < 0.01). No statistically significant differences were found in the amplitudes of the b-waves. The a-wave appeared at lower stimulus intensity (P < 0.05) and the a-wave slopes were significantly steeper (P < 0.01) during propofol anaesthesia. CONCLUSION: Propofol accordingly appeared to preserve the photoreceptor response better than thiopentone, and may therefore be considered to be more suitable for ERG recordings than thiopentone.

Anesthetics, Intravenous↗
PubMed1994

Early morphometry of a retinal dystrophy in Labrador retrievers.

Retinal morphometry was assessed in 7 dogs from a colony of Labrador Retrievers with dystrophic retinas at 1,2,3,4 and 18 months of age. Rod outer segment length and outer nuclear layer width were measured in the central, midperipheral and peripheral retina at six locations along the vertical meridian. Early striking regional differences in onset and rate of progression were characteristic for this inherited retinal degeneration. Notably, some areas of the retina developed fully and normally before degenerating. The central parts of the vertical meridians showed slightly disorganized rod outer segments already at 1 month of age and they were significantly shorter than those of control animals at 3 and 4 months (p < 0.01 and p < 0.001, respectively). The rod outer segments of the midperipheral and peripheral regions were, however, comparable to control animals as late as at 4 months of age. At 18 months the rod outer segments of dystrophic animals were significantly shorter in all retinal regions (p < 0.0005). At the age the outer nuclear layer of the dystrophic animals had become significantly thinner than that of control animals in all retinal regions (p < 0.001), indicating a clear visual cell loss. It is reasonable to characterize this as a retinal degeneration having a relatively slow progression, which enhances its relevance to conditions of clinical significance.

Aging↗
PubMed1991

Ultrastructural and ERG findings in progressive rod-cone dystrophy in a litter of Labrador retrievers.

Early ultrastructural findings of a progressive photoreceptor dystrophy and corresponding ERG findings are reported in 3 Labrador Retrievers from a litter of 7 pups bred from 2 dogs clinically and electroretinographically affected with generalized progressive retinal dystrophy. The pups were euthanized at 5, 11 and 15 months post partum. The most prominent ultrastructural finding was photoreceptor dystrophy. At 5 months the outer nuclear layer (ONL) consisted of 8-10 layers and seemed reduced in thickness, pyknotic nuclei were seen in this layer. The receptor outer segments (OS) were short and swollen. Some disorientation of OS discs occurred. In the 11-months specimen 7-8 ONL layers were identified. Overall thinning of the neuro-retina had occurred and fewer receptors compared to the 5-months specimen were present. By 15 months the ONL was further reduced to about 4 layers. Enlarged internuclear spaces were present in the ONL as well as around inner segments (IS). Phagocytic cells were frequent among remains of OS. The pigment epithelium appeared normal. The dark adapted ERG b-wave amplitudes and photopic 30 Hz flicker responses were low in comparison to controls of the same breed, and decreased with age. The condition represents a progressive rod-cone dystrophy which shares similarities with primary receptor dystrophy in man such as retinitis pigmentosa.

Animals↗
PubMed1990

A late receptor dystrophy in the Labrador retriever.

Dark adapted single flash and light adapted 30 Hz photopic flicker ERGs were recorded from a litter of seven Labrador Retrievers bred from parents affected with generalized progressive rod-cone dystrophy. After an initial increase of b-wave amplitudes from 5 weeks to 4 months similar to the controls, the b-wave amplitudes of the litter were significantly decreased (P less than 0.005) at 7 months. At 21 months the b-wave amplitudes were very low, although some response to 30 Hz photopic flicker was still left. The ERG changes indicated a late onset progressive rod-cone dystrophy which developed after maturation of the retina. The development of this photoreceptor dystrophy has not previously been described.

Animals↗
PubMed1989

Spontaneous recovery of residual neuromuscular blockade after atracurium or vecuronium during isoflurane anaesthesia.

With atracurium and vecuronium, spontaneous recovery of residual neuromuscular blockade monitored electromyographically during 0.5% isoflurane anaesthesia was studied in 60 patients undergoing plastic surgery. After thiopentone, in random order, either atracurium 0.5 mg kg-1 or vecuronium 0.1 mg kg-1 was administered and isoflurane added to N2O and O2 mixture. Following spontaneous recovery of both the single twitch amplitude (T1) to 75% of the control value and the train-of-four ratio (TOF ratio) to 75%, incremental doses of the relaxant were given to maintain the T1 at less than 10%. Before the end of surgery, the blockade was again permitted to recover spontaneously. During the initial spontaneous recovery, the mean recovery time of T1 from 25% to 75% (the recovery index) with atracurium was longer (P less than 0.001) than that with vecuronium (13.2 min and 10.1 min, respectively) but, during the second recovery, the mean recovery index was shorter (P less than 0.05) with atracurium than with vecuronium (16.1 min and 19.8 min, respectively). The recovery time from T1 75% to TOF ratio 75%, indicating the recovery rate of residual neuromuscular blockade, with atracurium was about 15 min after both the initial and the second recoveries. With vecuronium, the respective recovery times were significantly (P less than 0.001) longer (25.6 min and 38.5 min, respectively). It is concluded that with vecuronium there is slower spontaneous recovery of residual neuromuscular blockade than with atracurium.

Adult↗
PubMed1988

Serum creatine kinase levels after succinylcholine in children with "muscle, eye and brain disease".

Four boys belonging to a group of children affected by a rare form of muscular dystrophy with eye and brain involvement, termed the "muscle, eye and brain disease" (MEB), were anaesthetized for various eye examinations and surgery. On some occasions succinylcholine was used during anaesthesia and the initially elevated serum creatine kinase (CK) values increased from a range of 122 to 1200 units.L-1 to a range of 4350 to 9690 units.L-1 22 hours after anaesthesia. CK values after anaesthesia without succinylcholine remained at the initially elevated levels. Rectal temperatures of the children were normal. These findings suggest that succinylcholine should be avoided in patients with MEB disease.

Anesthesia↗
PubMed1988

Sleep effect of rectal methohexitone (10 mg/kg) in children premedicated for anaesthesia.

Methohexitone (10 mg/kg) was administered before 464 general anaesthesias for 317 children following intramuscular atropine and pethidine for various ophthalmological procedures. Approximately 70% of the children were asleep when anaesthesia was continued or started, usually with halothane in nitrous oxide and oxygen. Although the dose of methohexitone used here was smaller than that recommended in the literature, the results of the study did not greatly differ from earlier investigations in which no other premedication was given but where 20 mg/kg methohexitone was used.

Administration, Rectal↗
PubMed1987

Concomitant problems to the anaesthesia of diabetic vitrectomy patients.

Problems related to general anaesthesia of 109 consecutive vitrectomies performed on diabetic patients were retrospectively reviewed. On the morning of surgery a normal or a slightly reduced dose of the patient's regular insulin was administered subcutaneously. The amount of intravenous infusion, mostly 5% glucose, was calculated according to the pre-operative urine volume. After surgery, hypoglycaemic (less than 3 mmol/l) values were seen in less than 11% of the patients, and high glucose in less than 30%; 20% had a mild ketoacidosis post-operatively. Difficulties in tracheal incubation was encountered in 10%. Three patients complained of chest pain after surgery, and in one of them a myocardial infarction was diagnosed. Forty-one per cent of the patients complained of nausea or vomited in the afternoon after surgery, and 21% had difficulties in urination the night after surgery. Two of four patients with peritoneal dialysis complained of stomach pain post-operatively. There was no significant association between recurrent vitreous haemorrhage and blood glucose concentration or arterial blood pressure in the early post-operative period.

Anesthesia, General↗
PubMed1987

Characteristics and survival of diabetic patients undergoing vitreous surgery.

Characteristics, and the occurrence of other diseases, and complications related to diabetes mellitus of 91 consecutive diabetic patients who underwent vitreous surgery in 1979-1985 were examined. The mean age of the patients was 40 years (median 37, range 19-74), and the mean duration of diabetes 23 years (range 5-44). All, but one, had insulin therapy. Abnormalities in the cardiovascular and/or renal function were found in 89 of the 91 patients (98%). Signs of cardiovascular disease were observed in 58 patients (64%): 42% had elevated blood pressure (greater than or equal to 150/100 mmHg), 46% were on antihypertensive therapy, 14% had a history or signs of ischaemic heart disease, 12% had been digitalized, 7% had a history of cerebral ischaemia, and 8% had had surgery for gangrene of the lower limb. Signs of nephropathy were recorded in 64 patients (70%); 6 of them were on dialysis therapy, and two had received a kidney transplant. Symptoms possibly related to autonomic neuropathy e.g. postural hypotension, urinary tract symptoms, and gastric discomfort were found in 27%. Nine patients (10%) had some kind of thyroid disease, and two of them signs of multiple autoimmune endocrinopathy. The percentage surviving decreased from 96% at one year to 80% after 5 years of follow-up.

Adult↗
PubMed1986

Adverse reactions to fluorescein angiography.

Adverse reactions to ophthalmic patients during 9909 fluorescein angiographies during 9 years were registered. Nausea (4.6%) and vomiting (1.3%) were the most common untoward reactions. Allergic skin manifestations occurred in 48 patients, and 5 patients complained of shortness of breath. 56 patients (0.6%) felt dizzy during or immediately after the investigation. Nine patients complained of chest pain, three of whom developed myocardial infarction. Sixteen patients collapsed during the procedure. One healthy male, 42-year-old, collapsed after the injection of fluorescein during angiography, and electrocardiogram showed an asystole of 24 seconds. Otherwise, the electrocardiograms registered on 100 consecutive patients did not reveal any systematic changes in heart rate or rhythm during fluorescein angiography.

Adolescent↗
PubMed1985

Comparison of four non-depolarizing neuromuscular blocking drugs in the suppression of the oculocardiac reflex during strabismus surgery in children.

Eighty children (aged 2-12 yr) undergoing strabismus surgery were randomly assigned to receive tubocurarine, alcuronium, pancuronium or vecuronium during anaesthesia with thiopentone, fentanyl and nitrous oxide in oxygen. Heart rate and rhythm were recorded before and after the induction of anaesthesia and before and during traction on an extraocular muscle. End-tidal carbon dioxide concentration and the degree of neuromuscular blockade were monitored. Alcuronium seemed to give more protection against the oculocardiac reflex (defined as a 20% decrease in heart rate) than did tubocurarine, pancuronium or vecuronium.

Alcuronium↗
PubMed1985

Psychiatric reactions complicating intracapsular cataract surgery. A 5 years follow-up.

This follow-up study describes the 47 patients out of 1506 intracapsularly extracted cataracts (1505 patients) who presented with a psychotic reaction post-operatively. Matched non-psychotic cataract patients served as a control group. The mean age of both groups of patients was 78 years at time of surgery, female/male ratio was 39/8, and the mode of anaesthesia was local analgesia/general anaesthesia 16/31. The surgery had been performed in 1977-1979 and this follow-up examination in autumn 1983. Twenty-seven patients of the study group and 16 of the controls had died during the interval period. The difference between the groups was statistically significant. The patients of the study group were statistically significantly more dependent on nursing, and their mental performance, according to an orientation test, was more reduced, compared to the controls. Visual prognosis in the operated eye was unfavourable in the study group, versus the controls, mainly because of visual deprivation due to mental debilitation. Pre-operative vision did not predict future psychotic reaction.

Aged↗
PubMed1984

The oculocardiac reflex in adults. A dose response study of glycopyrrolate and atropine.

Ninety adult patients about to undergo strabismus surgery received glycopyrrolate or atropine intramuscularly. Three doses of each anticholinergic were studied. Cardiac rate and rhythm were recorded during halothane anaesthesia. The oculocardiac reflex, defined as a fall of 20% in heart rate during traction of the extraocular muscle was inhibited in a dose-dependent manner by the drugs studied. The potency ratio of glycopyrrolate to atropine according to the oculocardiac reflex was established as 1:2.

Adolescent↗
PubMed1982

Changes in the electroretinogram and visual evoked potentials during general anaesthesia using enflurane.

Fourteen female patients 27.7 +/- 10.0 years of age were studied by electrophysiological means before and during general anaesthesia. A mixture of thiopentone sodium, enflurane and nitrous oxide was used for anaesthesia. Electroretinogram (ERG) and visual evoked potentials (VEP) were recorded with electrodes placed on the lower lid and scalp and an averaging technique was used. The recordings were made under standard conditions with the pupils dilated, the eyes adapted to the dark and after 15-20 min stable anaesthesia. The latency of the a-wave did not change, whereas the b-wave was delayed (P less than 0.01). The amplitude of the a-wave tended to decrease; however, an increase of amplitude was also present. Therefore the change was not significant. The b-wave was unchanged. Changes induced by anaesthesia were often noted in the shape of P130, where a change from V to W-form took place or the reverse. The latencies of the late components N180 and P220 were increased during anaesthesia (P = 0.006 and P = 0.001, respectively). No statistically significant change occurred in the N180 and P220 amplitudes. The amplitudes of N60 and P130 became smaller (P = 0.002 and P = 0.0003, respectively) during anaesthesia. The effect of enflurane on the components of the VEP seems to indicate a cortical site of action.

Anesthesia, General↗