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Biomedical subjects

S Mikkelsen

Publications and source records attributed to S Mikkelsen.

At least 37 records · Page 2Linked to original sources
PubMed1998

The Harris Design-2 total hip replacement fixed with so-called second-generation cementing techniques. A ten to fifteen-year follow-up.

We analyzed the clinical results of 195 Harris Design-2 total hip replacements performed with so-called second-generation cementing techniques in 166 consecutive patients who had osteoarthrosis. The mean age of the patients at the time of the replacement was sixty-seven years and nine months (range, thirty-one to eighty-nine years). Forty-eight patients (fifty-four hips) died before the time of the latest follow-up, but the implants were apparently functioning well at the time of death. Three patients (four hips) were lost to follow-up. Five patients (five hips; 3 percent) had a revision because of aseptic loosening of the acetabular or femoral component, or both, that was related to wear-induced osteolysis. The mean Harris hip score for the 131 hips that were available at the latest follow-up examination at a mean of twelve years (range, ten to fifteen years) after the operation was 89 +/- 10 points. On the basis of the Harris hip score, seventy-six hips had an excellent result, thirty-four had a good result, fifteen had a fair result, and six had a poor result at the latest follow-up examination. Radiographically, twelve (9 percent) of the 131 acetabular components and three (2 percent) of the 131 femoral components were probably or definitely loose. At a mean of twelve years, 186 (97 percent) of 191 Harris Design-2 implants were in situ or had been in situ at the time of the patient's death.

Aged↗
PubMed1997

Norketamine, the main metabolite of ketamine, is a non-competitive NMDA receptor antagonist in the rat cortex and spinal cord.

The enantiomers of the potent non-competitive NMDA receptor antagonist ketamine and its major metabolite, norketamine were evaluated as NMDA receptor antagonists using the rat cortical wedge preparation and the neonatal rat spinal cord preparation, respectively, for electrophysiological studies and [3H](RS)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-im ine ([3H]MK801) in homogenate binding experiments. In agreement with earlier studies (S)-ketamine (Ki 0.3 microM) was found to possess a 5 times higher affinity for the NMDA receptor complex than (R)-ketamine (Ki 1.4 microM). (S)-Norketamine (Ki 1.7 microM) had approximately an 8 times higher affinity than (R)-norketamine (Ki 13 microM) in the inhibition of [3H]MK-801 binding. All compounds inhibited responses to NMDA in the rat cortical wedge preparation and the hemisected neonatal rat spinal cord, being approximately four times more potent in the cortex than in the spinal cord except for (R)-norketamine being only twice as potent. In light of the clinically obtained concentrations of norketamine after oral administration of ketamine, these data strongly suggest that (S)-norketamine may contribute significantly to the clinical activity of (S)-ketamine, especially when given orally.

Animals↗
PubMed1997

Epidemiological update on solvent neurotoxicity.

Epidemiological studies of occupational mixed solvent exposure were reviewed for evidence of exposure-related neuropsychiatric disorders, mental symptoms, and neurobehavioral performance. Studies of workers receiving disability pensions found consistent evidence of an increased risk of neuropsychiatric disability among solvent-exposed workers. Study results differed, however, with respect to relations between solvent exposure and specific diagnostic entities. These differences may be attributed to cross-country differences in diagnostic entities and criteria for disability pension eligibility. Psychiatric morbidity studies found no relation between occupational solvent exposure and admission to a hospital for psychiatric illness. Alcohol abuse and solvent exposure in combination seemed to be a risk factor for dementia and cerebral degeneration. Cross-sectional studies supported the hypothesis that occupational, low-level, long-term solvent exposure may cause adverse central nervous system effects. Several studies that used complex measures of lifetime cumulative and average exposure demonstrated significant dose-response relations between exposure, mental symptoms, and neurobehavioral performance. There were discrepancies, however, in the degree of exposure causing these adverse effects. The cumulative findings strongly suggest that occupational solvent exposure may be the cause of mental and cognitive impairment that may become chronic and disabling. The adverse central nervous system effects observed in these studies seemed to occur at exposure levels well below accepted threshold limit values. Lowering these values should be considered.

Case-Control Studies↗
PubMed1997

Pneumopericardium associated with high-frequency jet ventilation during laser surgery of the hypopharynx in a child.

A case of pneumopericardium, without concomitant pneumothorax, resulting from high frequency jet ventilation during laser surgery of the hypopharynx is described. The patient, a four-year-old boy, suffered cardiac arrest as a consequence of the incident. The pneumopericardium was likely to have been caused by obstruction to the expiratory flow during surgery. Other possible explanations for the incident are discussed.

Child, Preschool↗
PubMed1997

Studies on the bioavailability of glyceryl trinitrate after sublingual administration of spray and tablet.

The plasma profiles of nitroglycerin (glyceryl trinitrate, GTN, CAS 55-63-0) were estimated after two sublingual puffs of 0.4 mg GTN from a fluorochlorohydrocarbon (FCH)-free oral spray and one sublingual tablet of 0.5 mg GTN (Nitromex). The study was carried out in an open, randomized, two-phase, cross-over design with 24 volunteers. Eighteen blood samples were taken within 30 minutes after administration, and the plasma concentrations of GTN were determined by a specific gas chromatographic method with electron capture detection. The pharmacokinetic parameters, Cmax, tmax, and AUC, were determined for each volunteer. After correction of the AUC and Cmax values of the oral spray by dividing by two, the ratios (spray/tablet) of the AUC and Cmax and the 90% confidence intervals were estimated. The plasma concentrations of GTN (mean) after the spray (dose: 0.8 mg GTN) reached a maximum of 3.96 ng/ml (range: 0.99-10.86) at 3.5 minutes (range: 2-5). The plasma concentrations of GTN (mean) after the tablet (dose: 0.5 mg GTN) reached a maximum of 1.97 ng/ml (range: 0.57-4.33) at 4.9 minutes (range: 3-7). The corrected ratios (spray/tablet) of AUC and Cmax were 1.02 and 0.97 with the 90% confidence intervals (0.80, 1.30), respectively (0.77, 1.24). The results indicate that the oral spray in a dose of 0.4 mg is equivalent to the sublingual tablet in a dose of 0.5 mg.

Administration, Sublingual↗
PubMed1995

Peritonsillar infiltration with low-dose tenoxicam after tonsillectomy.

We have compared the effect of peritonsillar infiltration with tenoxicam 5 mg and placebo on postoperative pain after tonsillectomy. Fifty patients undergoing bilateral elective tonsillectomy under general anaesthesia were allocated randomly to receive peritonsillar infiltration with tenoxicam 5 mg in 8 ml of normal saline (4 ml per tonsil) or normal saline only, before tracheal extubation. Median time to first request for morphine (30 min in each group, P = 0.83), cumulative morphine requirements from 0 to 2 h after surgery (two and one doses, P = 0.50), and from 2 to 24 h after surgery (one dose in each group, P = 0.17) were similar. There were no significant differences between groups in VAS scores at rest or when drinking 100 ml of water at any time. The power of detecting a reduction in VAS scores of 20 mm was 90% at the 5% significance level.

Adolescent↗
PubMed1995

Prognosis of vibration induced white finger: a follow up study.

OBJECTIVES--To follow up 102 patients with vibration induced white finger (VWF). METHODS--102 subjects with VWF were reexamined one to 13 years after the condition had first been diagnosed. Information about symptoms, occupation, vibration exposure, smoking habits, age, and the prevalence of other diseases was present in the medical records from the first examination and was collected by a questionnaire and an interview at the second examination. The decrease in systolic blood pressure in a finger during cold provocation (FSP%) was measured in the same finger at both examinations. RESULTS--At the second examination, 22% stated that the frequency of attacks had decreased. The improvement was most frequent in subjects with little or no exposure to vibration during the previous two years, in non-smokers, and in subjects without other circulatory diseases than VWF. 32% stated that the frequency of attacks had increased. The aggravation was most notable in smokers and subjects who also had circulatory diseases other than VWF. The number of finger phalanges that blanched on cooling averaged 15.8 at the first examination and 14.4 at the second examination. Working with high vibration hand held tools during the previous two years was related to an aggravation, with more finger phalanges affected at the second examination. Presence of other circulatory diseases had the same effect. In non-smokers the number of affected finger phalanges had decreased at the second examination. The FSP% had increased (improvement) in 43%, decreased (aggravation) in 12%, and was unchanged in 45%. The increase in FSP% was more pronounced in the older than in the younger subjects. The decrease of FSP% was more frequent among the younger subjects and subjects with a short follow up. CONCLUSION--As the FSP% in nearly half of the subjects had improved, it is concluded that VWF has a good prognosis in patients with mainly moderate to severe VWF after one to 13 years of observation. The improvement in FSP%, however, was not reflected in the subjective experience of the development of attacks of VWF. Continued work with high vibration hand held tools, smoking, other circulatory diseases, and low age at the time of diagnosis had an unfavourable influence on the prognosis.

Adult↗
PubMed1995

Patients' experience of rehabilitation after stroke.

In this study patients were interviewed concerning their experience of rehabilitation in an experimental stroke unit. The patients reported positive effects of being together with other stroke patients and used the unit in a self-help group fashion. They felt that they could have used more rehabilitation, even though they were hospitalized for longer than reported in other studies. Patients felt that there were important non-physical problems in connection with their rehabilitation, and that sufficient attention was not given to all of these. Finally patients underlined the positive effects of the rehabilitation process in helping them organize their coming life in the community.

Adaptation, Psychological↗
PubMed1995

Therapists and the rehabilitation process after stroke.

Therapists working in an experimental stroke unit were interviewed about how they set goals for rehabilitation, how they measure progress, and about problems of discharging patients. In addition the interview covered the topics of quality in rehabilitation, the relationship between patient and therapist, and therapists' evaluation of the stroke unit. The therapists felt that current outcome measurement instruments did not capture the kinds of results that they felt were important. They were process-oriented, and not only outcome-oriented as in traditional studies of stroke rehabilitation. This explorative study provides an insight into how therapists view the stroke rehabilitation process, and elaborates themes for future studies of physical and occupational therapy in rehabilitation.

Attitude of Health Personnel↗
PubMed1994

Morphine pharmacokinetics in premature and mature newborn infants.

The pharmacokinetics of a single dose of morphine was investigated in five term infants (gestational age 37-40 weeks) and eight preterm infants (gestational age 25-32 weeks). In the five term infants, median (range) volume of distribution at steady state (Vd beta) was 1758 (634-2700) ml/kg, plasma clearance (Cl) was 4.73 (1.75-6.61) ml/kg/min and terminal half-life (T1/2) was 224 (107-394) min. In the eight preterm infants, Vd beta was 2366 (1662-2876) ml/kg, Cl was 2.82 (1.88-6.60) ml/kg/min and T1/2 was 556 (248-834) min. No correlation was found between clearance and gestational age, but we found a significant negative correlation between T1/2 and gestational age. We conclude that there is considerable variation in the pharmacokinetic properties of morphine in both term and preterm newborn infants. Because of this variation, careful individual assessment of the clinical effect of therapy with morphine in newborn infants should be exercised.

Gestational Age↗
PubMed1994

Chronic interstitial nephropathy after plasma cutting in stainless steel.

Chromium is nephrotoxic in experimental animals. In subjects with acute chromium intoxication acute nephritis has been reported and renal function has been affected in chromium exposed workers with a high urinary chromium concentration. Chronic kidney disease after long term occupational exposure to chromium has, however, not been reported previously. A case report is presented concerning a 48 year old man who was diagnosed with chronic interstitial nephropathy. He had worked for nine years as a plasma cutter of stainless steel and had thereby been exposed to smoke containing chromium. At the time of diagnosis his blood chromium concentration was seven times higher and his urinary chromium concentration six times higher than reference values. Taking into account the nephrotoxicity of chromium and the high chromium burden of this patient it is considered likely that his exposure to smoke from plasma cutting of stainless steel was the cause of his chronic interstitial nephropathy.

Chromium↗
PubMed1993

[Prevention of aspiration in obstetric patients in Denmark].

Women about to undergo Caesarean section are especially prone to suffer from aspiration of acid gastric contents into the lungs during anaesthesia. Physiological changes in the pregnant patient make gastric emptying time unpredictable. It therefore seems prudent to establish procedures in order to minimize the risk of aspiration of gastric contents. This survey reveals that 25% of the obstetric-anaesthesiological departments in Denmark employ pharmacological prophylaxis for aspiration of acid gastric contents. This finding is in contrast to a similar survey in the United Kingdom, where 99 to 100% of the Caesarean sections are carried out under pharmacological prophylaxis for aspiration of acid gastric contents.

Adult↗
PubMed1992

[PermCath as intravenous access in chronic hemodialysis].

PermCath is a dual-lumen silicone catheter for permanent venous access for hemodialysis. During an observation period from 1 July 1988 to 30 June 1991, 49 PermCath were inserted in 32 patients. In 24 patients (75%), the PermCath was used as sole method of access for hemodialysis through the observation period. Six of the 24 patients required changing of the catheter once, and in three patients the PermCath functioned properly only after the third insertion of a PermCath. In eight patients, vascular access could not be accomplished using the PermCath and these patients were all hemodialyzed through another vascular access. Four patients developed bacteraemia and one patient developed thrombosis of the subclavian vein during the observation period. Insertion of the PermCath is easy and, in case of malfunction, changing or removal of the catheter is easily accomplished. The PermCath is recommended as an alternative to existing techniques for intravenous access for hemodialysis.

Adolescent↗
PubMed1992

Recovery following thiopentone or propofol anaesthesia assessed by computerized coordination measurements.

Quantitative measurements of coordination ability and performance speed were carried out on 76 female day-case patients undergoing minor gynaecological operations. The women were assigned at random to the anaesthetic agent used, propofol 2.5 mg/kg or thiopentone 4 mg/kg. Spacing control, timing control and performance speed were recorded using a newly developed computerized coordination ability test system. The patients were tested once before the operation and 0.5, 1 and 2 h after awakening. Postoperatively the initial impairment and the subsequent regression towards preoperative test results were very similar whether the anaesthetic agent was propofol or thiopentone. Although the test apparatus was able to detect even minor differences, no postoperative test showed statistically significant differences between the two groups. We find it reasonable to conclude that there is no difference in recovery of coordination ability following propofol- or thiopentone-induced anaesthesia.

Adolescent↗
PubMed1991

[Settling times for occupational diseases reported to the National Board of Industrial Injuries].

A representative sample of 151 cases notified to the National Board of Industrial Injuries on a suspicion of an occupational disease were studied with respect to time from notification to final settlement of the case. 50% were settled within 5.5 months, and 75% within 10 months. Settling times were longer for cases accepted for compensation than for dismissed cases. The time used to investigate a case constituted an increasing proportion of the total settling time with increasing settling times. For cases with a settling time of more than nine months, approximately half of the time consisted of waiting time to obtain required information from external sources. It is concluded that a substantial reduction of cases with long settling times depends on a reduction of external expedition times for obtaining required information. The medical profession can contribute to the reduction of settling times by elucidating the case meticulously at the time of notification and by reducing expedition times for requisitions for information.

Denmark↗
PubMed1990

Computerized coordination ability testing.

Quantitative measurements of coordination ability were carried out on 76 women with a median age of 37, range 15 to 60. Spacing control, timing control and performance speed were recorded using newly developed computerized equipment, Catsys, presented in this paper. Twenty-three subjects were re-examined 2-3 months after the first measurements. A fair or even high degree of reproducibility of tests was found. Normal values for the entire group and correlation values for the re-examined group are presented. The results from this small study implies that the Catsys may be useful, e.g., in future clinical neurological practice of diagnostics and follow up on patients, in occupational medicine for detection of neurotoxic effects of various neurotoxic substances, in evaluation of drug effects and side effects and for testing people in occupations where normal coordination skills are absolutely necessary.

Adult↗