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Biomedical subjects

L Knudsen

Publications and source records attributed to L Knudsen.

At least 73 records · Page 4Linked to original sources
PubMed1990

An inter-Nordic prospective study on cytogenetic endpoints and cancer risk. Nordic Study Group on the Health Risk of Chromosome Damage.

To investigate whether high rates of chromosomal aberrations (CAs), sister chromatid exchange (SCE), or micronuclei(MN) in peripheral lymphocytes indicate an increased risk for subsequent cancer, a prospective cohort study of 2,969 subjects cytogenetically examined between 1970 and 1988 in four Swedish, two Finnish, and two Norwegian laboratories was initiated. To standardize for the interlaboratory variation, the results of the three cytogenetic endpoints were trichotomized for each laboratory into "low" (1st to 33rd percentile), "medium" (34th to 66th percentile), and "high" (67th to 100th percentile]. Thirty-four cancers had been diagnosed in the cohort during the observation period (1970 to 1985). The point-estimates of the standardized morbidity ratio (SMR) in the three CA strata were 90, 92, and 180, respectively. This trend for a positive association was not statistically significant (p = 0.06). There was no significant trend between SMR and the trichotomized rates of SCE. In the subcohort examined for MN only two cases of cancer had been diagnosed until now. If subjects with "high" frequencies of CA or SCE have a two-fold (or greater) risk of developing cancer as compared with individuals who have "medium" or "low" frequencies, we estimate that there is a likelihood of 80% and 70%, respectively, that this will be detectable as significant (p less than or equal to 0.05) differences after a further follow-up period of 5 years. Weaker associations between cancer risk and the cytogenetic endpoints would not be possible to evaluate until even later follow-ups.

Chromosome Aberrations↗
PubMed1990

Eight to ten years follow-up after carotid endarterectomy: clinical evaluation and Doppler examination of patients operated on between 1978-1980.

Follow-up information was obtained on 185 patients who consecutively underwent carotid endarterectomy eight to ten years previously. Doppler ultrasound examination was performed in 59 patients who were still alive and living within 100 miles of the hospital. Using lifetable analysis, the annual rate of focal strokes was estimated to be 2% and 1.5% on the operated and the contralateral, non-operated carotid artery, respectively. Doppler examination revealed 48% re-stenoses, including 14% occlusion and 15% greater than 50% stenosis. However, there was no association between the occurrence of restenosis and the development of symptoms, perhaps with the exception of internal carotid artery occlusion, which is not an accepted indication for carotid endarterectomy. Together with recent data from the literature, these observations challenge the indication for reoperative carotid surgery.

Carotid Arteries↗
PubMed1990

The effects of midazolam on cerebral blood flow and oxygen consumption. Interaction with nitrous oxide in patients undergoing craniotomy for supratentorial cerebral tumours.

Cerebral blood flow and the cerebral metabolic rate of oxygen were measured in 30 patients during craniotomy for supratentorial cerebral tumours by a modification of the Kety-Schmidt technique using Xenon 133 intravenously. Anaesthesia was induced with midazolam 0.3 mg/kg, fentanyl and pancuronium, and maintained with midazolam as a continuous infusion, fentanyl, pancuronium and nitrous oxide in oxygen or oxygen in air. The concentration of midazolam in the blood of 10 patients was about 300 ng/litre during two measurements; the patients' lungs were ventilated with N2O in oxygen. The concentration of midazolam in the blood of another 10 patients was doubled to about 600 ng/litre during the second flow measurement; the patients' lungs were ventilated with N2O/O2. The concentration of midazolam in the blood of the third group of 10 patients was doubled to 600 ng/litre during the second flow measurement; the patients' lungs were ventilated with oxygen in air. No relationship was found between the dose of midazolam and cerebral blood flow or oxygen consumption. Nitrous oxide in combination with midazolam also had no effect on these variables.

Adult↗
PubMed1990

Regulation of renal pelvic pressure by diuresis and micturition.

The influence of the voiding cycle and diuresis on the hydrodynamic pressures of the renal pelvis in the multicalyceal kidney of miniature pigs has been examined. Identification of the pressure patterns characteristic of the renal pelvis with an undisturbed pelviureteric and ureterovesical junction was emphasized. The frequency and amplitude of contractions in the renal pelvis were measured bilaterally. The patterns of renal pelvic pressure changes were interpreted during bladder filling and emptying and diuresis to evaluate the mechanisms facilitating the pressure isolation of the upper urinary tract. These studies were undertaken in the awake pig equipped with a long-term radiotelemetry implant transmitting renal pelvic and urinary bladder pressure. The results show that renal pelvic contractions are low-pressure events having an amplitude of 10.3 +/- 4.2 cmH2O and a frequency of 6.6 +/- 0.7 contractions/min. During basal hydration, the process of renal pelvic filling and emptying is active, with rhythmic pelvic contractions. The left and right renal pelvis demonstrate approximately equal frequency, 1.04:1.00, but are not synchronous. Furosemide-stimulated diuresis produces radical changes in the renal pelvis by transforming emptying from an active to passive mode and facilitating the transmission of voiding pressures and spontaneous bladder pressures to the kidney.

Animals↗
PubMed1989

[Traditional and alternative treatment of patients with multiple sclerosis].

The medicine consumption and the employment of alternative treatment were investigated in a material of 117 patients with disseminated sclerosis (DS) considered to be a representative sample of the patients with DS in the County of Funen. This investigation revealed that the preparations most commonly employed to modify the disease among patients with disseminated sclerosis were: spasmolytics, agents to counteract neurogenic bladder symptoms, benzodiazepine and analgesics. The consumption of medicine increased with increasing handicap. Employment of psychopharmaca was commonest in patients in social classes 4 and 5 and in women. In addition, is was found that there was no difference in social class, sex and age among the patients who employ alternative methods of treatment. The patients themselves have not experienced any effect from alternative treatment.

Adult↗
PubMed1989

[Flumazenil. A specific benzodiazepine antagonist].

Flumazenil (Lanexat) is the first specific benzodiazepine-antagonist for clinical use. In several controlled investigations, a significant rapidly commencing antagonistic effect on the central effects of benzodiazepines has been demonstrated. Flumazenil possesses only slight side effects which may easily be treated. The immediate indications for employing flumazenil are reversal of the sedation caused by benzodiazepines in outpatients and treatment of cases of poisoning. In addition, flumazenil could be employed to reverse sedation produced by benzodiazepines during general anaesthesia and prolonged sedation in intensive care units. The following should be observed on employing flumazenil: 1. Flumazenil should be administered by slow meticulous titration. 2. The relatively short half-life of flumazenil provides the possibility for partial return of CNS depression. 3. In cases of mixed poisoning, flumazenil may unmask the effects of possible seizure-producing drugs. 4. Care should be employed in using flumazenil in chronic benzodiazepine abusers.

Benzodiazepines↗
PubMed1989

[Referrals for carotid surgery during the period 1977-1986. The referral pattern for patients with carotid stenosis in the catchment region of the University Hospital in Copenhagen, assessed during a 10-year period].

Although carotid endarterectomy has been carried out for over 30 years, there are as yet no investigations which prove the value of this form of treatment with certainty. Attitudes to carotid surgery also vary greatly. The authors have assessed this variation during the period 1977-1986 on the basis of the lists of patients admitted to the Department of Vascular Surgery in the University Hospital. Patients from Funen and Jutland were excluded from the material because endarterectomy is also carried out in hospitals in these regions. A total of 720 patients from two extensive municipalities and six counties were admitted. During the period involved, increase in the number of referrals and also in the number of operations carried out occurred until 1984. After this, and in accordance with the global more restrictive attitudes, fewer patients were referred. Great regional variations were found as 8-10 as many patients per 100,000 inhabitants between 50 and 70 years were referred from the Municipality of Copenhagen as from the county which referred fewest patients. It is concluded that there are considerable differences in the treatment of patients with carotid stenosis within the catchment region of the University Hospital in Copenhagen.

Aged↗
PubMed1989

Flumazenil used for antagonizing the central effects of midazolam and diazepam in outpatients.

In a double-blind, randomized trial, the efficacy and safety of flumazenil, a benzodiazepine antagonist, was evaluated in patients after gastroscopy under midazolam or diazepam sedation. The criteria of efficacy were the degree of sedation and anterograde amnesia. Flumazenil significantly reduced the degree of sedation in both groups without significant intergroup differences. No sign of resedation was found during the observation period of 3 h. The anterograde amnesia was effectively antagonized in both groups. Flumazenil was well tolerated. Flumazenil is a safe and effective benzodiazepine antagonist which makes it possible to reduce the recovery period in outpatients sedated sufficiently with benzodiazepines for gastroscopy.

Adult↗
PubMed1989

Normative data for eight neuropsychological tests based on a Danish sample.

Normative neuropsychological data have been provided using a sample of 101 persons aged 20 to 54 years. Eighty-seven of the subjects were recruited among patients who had undergone minor surgery, and 14 subjects were volunteers from the staff at the hospital laundry. The measures consisted of seven subjects from the WAIS-R, the trail-making test, symbol digit modalities test, auditory-verbal learning test, story recall test, visual gestalt test, recurring figures test, verbal fluency, and Purdue pegboard test. These measures were selected because of suitability in regard to time taken for testing each subject and their sensitivity to subtle changes in neuropsychological functioning. The sample was arbitrarily divided into three age groups, and for each of the three samples, mean, standard deviation, and range were calculated for each test. The results of the Information and Vocabulary subtests from the WAIS-R, education, and social status were applied as independent variables in linear regression analyses where each of the neuropsychological tests, in turn, was the dependent variable. For the oldest age group, age in addition was used as an independent variable. Significant linear relationships, which accounted for an optimal part of the variance, were selected for clinical application.

Adult↗
PubMed1989

Reproducibility of iodine-123-hippuran renoscintigraphy in the normal pig at various flow rates.

Twenty-two pigs with normal kidney function and upper urinary tracts were examined with renoscintigraphies once a week for 4 weeks. In order to study the influence of urine flow on the reproducibility, renoscintigraphies were undertaken during various urinary flow rates. Renal split function was reproducible at any level of and independent of the urinary flow rates. For parenchymal and pelvic mean transit times a normogram was constructed for selected urinary flow intervals. An inverse relationship to urine production was seen. Parenchymal and pelvic transit times were fully reproducible when data were compared in two or three consecutive examinations of the same kidney at the same urinary flow rate. Both parenchymal and pelvic mean transit times were however significantly different (p less than 0.001) in kidneys studied from one urinary flow rate to another. Single kidney hippuran clearance was fully reproducible when compared in the same urinary flow interval. However a significant difference was found (p less than 0.05) when single kidney hippuran clearance was compared in renographies undertaken at different urinary flow intervals. Furthermore the study suggests that the size of hippuran clearance is dependent on the urine production, since an increase in hippuran clearance was seen in relation to increase in urinary flow. In conclusion this pig study showed, that monitoring of the urinary flow rate is extremely important in this very commonly used clinical investigation, and that the investigation should be performed in the same state of hydration at any renography to obtain reproducible results.

Animals↗
PubMed1988

Insulin treatment of the insulin-dependent diabetic patient undergoing minor surgery. Continuous intravenous infusion compared with subcutaneous administration.

In a prospective randomised study in 20 insulin-dependent diabetics who had minor surgery under general anaesthesia we compared the metabolic responses to intravenous glucose-insulin-potassium infusion with those who had conventional subcutaneous insulin administration. The former treatment resulted in lower blood glucose levels both during the infusion period (p less than 0.05) as well as the entire observation period (operative, first and second postoperative days; p less than 0.01). More blood glucose values were within the intended range of 5 to 10 mmol/litre in the glucose-insulin-potassium as compared to the conventional group (48% versus 24%; p less than 0.01). The levels of lactate, 3-hydroxybutyrate, glycerol, alanine, glucagon, insulin and growth hormone did not differ between the two groups. The infusion regimen resulted in better glycaemic control both peri-and postoperatively than the conventional subcutaneous insulin regimen in insulin-dependent diabetic patients who have minor surgery.

Adult↗
PubMed1988

Benzodiazepine intoxication treated with flumazenil (Anexate, RO 15-1788).

The efficacy and safety of flumazenil were assessed in comparison to placebo in a double-blind randomised study of 31 adults intoxicated with benzodiazepines. The criteria of efficacy were the degree of sedation, and orientation in time and space. Patients who received flumazenil awoke within minutes but central depression returned partly one hour later, which reflects the short elimination half-life of the drug. Side effects were few and the results indicate that flumazenil is effective in the primary management of benzodiazepine overdose and in states where benzodiazepines have been taken with other drugs.

Adolescent↗
PubMed1988

Flumazenil used in the antagonizing of diazepam and midazolam sedation in out-patients undergoing gastroscopy.

In two double-blind, randomized trials the efficacy and safety of flumazenil, the first benzodiazepine antagonist, were assessed in 100 adult patients undergoing gastroscopy under diazepam or midazolam sedation. The criteria of efficacy were the degree of sedation and anterograde amnesia. The median gastroscopy time was 20 min (range 5-40 min). The diazepam group received median 30 mg (range 15-60 mg) Diazemuls and the midazolam group median 15 mg (range 10-40 mg) Dormicum. Both groups were antagonized by median 0.42 mg flumazenil (range 0.4-0.6 mg). There was no inter-group difference with regard to blood pressure, heart rate and respiration rate. There was a significantly faster recovery of the patients after injection of flumazenil than after placebo. Patients were awake shortly after flumazenil, but remained drowsy or asleep after placebo administration. All patients, regardless of diazepam or midazolam sedation, antagonized with flumazenil were awake within 5 min and remained awake during the whole observation period of 3 h. The amnesia was totally eliminated by flumazenil. There were no significant differences in side-effects between the groups.

Adolescent↗