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Biomedical subjects

L Knudsen

Publications and source records attributed to L Knudsen.

At least 55 records · Page 3Linked to original sources
PubMed1993

Patterns of use of obstetrical interventions in 12 countries.

Recent obstetrical practice trends in 12 countries were surveyed. There was a 3-fold difference in caesarean section rates and a 10-fold difference in instrumental vaginal delivery rates among countries. There was a net increase in the caesarean section rate of all countries over the study period and a net decrease in the instrumental vaginal delivery rate of some countries. There was a decrease in the caesarean section rate during the last year of observation in Australia, Denmark and Finland. In general, countries with high caesarean rates also had high instrumental vaginal delivery rates. There was no consistent relationship between use of caesarean section and use of instrumental vaginal delivery, although in several countries increasing use of caesarean section was accompanied by decreasing use of instrumental vaginal delivery. Oxytocin use rates were associated positively with instrumental delivery but not with caesarean section rates. While it was not possible to determine the proportions of women who received appropriate obstetrical care, we can infer that a significant proportion of interventions were unnecessary or only marginally beneficial. Continued increases in rates of obstetrical intervention are unlikely to result in improvements in birth outcome overall and may pose a risk to mothers and their newborns.

Australia↗
PubMed1992

[Painful syndromes connected with disseminated sclerosis].

Multiple sclerosis (MS) is frequently regarded as a painless condition. A review of the literature reveals that approximately 2/3 of the patients with multiple sclerosis will experience painful syndromes during the course of disease and that these are associated with the disease. Acute syndromes are described: Trigeminal neuralgia, Lhermitte's sign, optic neuritis and tonic seizure. Chronic syndromes: Dysaesthesia, pain in extremities, muscular spasms, low back pain and headache. The frequency, causes and suggestions for treatment are mentioned. A Danish investigation has revealed that only 42% of a representative section of DS patients received adequate treatment for pain. It is thus concluded that optimal treatment of pain in MS patients is necessary.

Back Pain↗
PubMed1992

[The circumstances of life and need for social measures of patients with prolonged psychiatric illness].

The circumstances of life and the need for social support were investigated in 142 patients with prolonged psychiatric illness who sought help consecutively in the psychiatric casualty department or who were referred to the psychiatric department of Odense Hospital during the period 11 Sep. 1989-31 Dec. 1989. 80% of these were psychotic and 20% were borderline psychotic. Approximately 90% were young adults (20-49 years). Schizophrenic men predominated. More than 40% of all the patients had some form of addiction as a contributory diagnosis and 71% of the patients with borderline psychoses were addicts. Approximately 3/4 of the patients lived alone in flats. The level of occupational training was low as compared with the remainder of the population. The majority received early pensions. The majority lived in social isolation from the remainder of the community. Only a single patient had no fixed abode but suitable forms of residence where social support could be given were insufficient. Similarly, the requirements for possible employment and leisure activities were great.

Adult↗
PubMed1992

Obstructive nephropathy in the pig. Possible roles for insulin-like growth factor I.

Kidney growth was investigated in 30-kg pigs after 72 h of unilateral ureteral obstruction. The data were compared to control kidneys from normal non-operated pigs at same weight. Kidney wet weight was determined. Cortex and medulla were separated, and from both regions RNA, DNA, protein and kidney tissue insulin-like growth factor I was determined. Unilateral obstruction caused a doubling of the wet hydronephrotic kidney weight and an ipsilateral 76% increase in total kidney protein content. RNA increased by 45% in the cortex and 76% in the medulla. Kidney protein in the contralateral cortex increased by 23% and RNA by 42%. In the hydronephrotic kidney DNA was reduced by 13% in the cortex and by 21% in the medulla. Contralaterally, DNA was the same as in the controls. Mean kidney insulin-like growth factor I increased sevenfold in the ipsilateral medulla but in the cortex it was the same as in the controls. Serum insulin-like growth factor I concentration was 1.7 +/- 1.1 micrograms/l in the hydronephrotic animals and 1.2 +/- 0.8 micrograms/l in controls. At this stage of obstruction, our data demonstrate (1) hydronephrotic growth that is most probably hyperplastic in the medulla, associated with an increase in medullary insulin-like growth factor I, (2) hyperplastic growth in the cortex, and (3) contralateral kidney growth that is mainly hypertrophic after 72 h of contralateral ureteral obstruction.

Animals↗
PubMed1992

Enhanced intrarenal angiotensin II generation in response to obstruction of the pig ureter.

The effect of acute unilateral complete ureteral obstruction (UUO) on renal hemodynamics has been examined in a pig model. Pigs were operated on under general anesthesia, electromagnetic flow probes were inserted around renal arteries, and catheters were implanted in renal veins and aorta for blood sampling. The influence of 15 h of obstruction on the physiological variation in immunoreactive angiotensin II (ANG II) was measured together with detailed analysis of the renal handling of ANG II in anesthetized animals. Pelvic pressure rose significantly within 2 h to a maximum of 59.9 +/- 2.9 cmH2O (n = 10). The ipsilateral renal blood flow (RBF) was reduced by 30% from 319 +/- 35 to 241 +/- 42 ml/min (P = 0.001), whereas contralateral RBF did not change. A temporary significant increase in mean aortic blood pressure was seen during the first 2 h after UUO. Renal vascular resistance increased by 44% in the obstructed kidney from 37 +/- 3 to 55 +/- 9 mmHg.ml-1.min.g during the course of obstruction. Concomitantly, the plasma concentration of immunoreactive ANG II increased from all three sample sites by 8-15 times. This increase was highly significant compared with the sham-operated group. The results show that the pig kidney responds to UUO by a net secretion of ANG II from the ipsilateral kidney. Our observations on the ANG II renal secretion rate suggest that part of the immunoreactive ANG II in the renal venous effluent originated de novo from intrarenal generation.

Angiotensin II↗
PubMed1992

The impact of total unilateral ureteral obstruction on intrarenal angiotensin II production in the polycalyceal pig kidney.

Nine pigs with unilateral complete ureteral obstruction were investigated for 15 hours. Obstruction of the ureter resulted in a maximum intrapelvic pressure of 60 cmH2O within the first hour after obstruction, and a gradual decline to 40 cmH2O during the next 15 hours. In 6 pigs both renal veins were catheterized together with the abdominal aorta allowing measurement of the hormonal difference over the kidney. Plasma angiotensin II, plasma vasopressin and plasma atrial natriuretic peptide concentrations were determined. Arterial concentration of plasma angiotensin II gradually increased from 38.7 pg/ml to 252.3 pg/ml. The highest concentrations of angiotensin II were found from the ipsilateral renal vein. From 1 hour after obstruction and onward there was a negative extraction ratio of angiotensin II from the ipsilateral kidney indicating enhanced intrarenal generation of angiotensin II. No difference in vasopressin was found among the sample sites, but a significant reduction in vasopressin from 15.2 pg/ml to 4.9 pg/ml was found from the ipsilateral renal vein during the 15 hours of unilateral ureteral obstruction. Arterial atrial natriuretic peptide concentrations were higher than renal venous levels at all times. Glomerular filtration was immediately reduced to 58%. It is suggested that an increased ipsilateral generation of intrarenal angiotensin II is at least partly responsible for some of the changes in kidney function during acute obstruction.

Angiotensin II↗
PubMed1991

[Perioperative treatment of diabetics].

The metabolic changes in connection with fasting, anaesthesia and surgery in diabetic patients and non-diabetic patients are reviewed. Various perioperative forms of treatment are described. The forms of treatment most commonly employed are infusion of glucose-insulin-potassium (GIK) and subcutaneous administration of insulin followed by infusion of glucose (KON). The more intensive GIK regime provides the diabetic patient with a biochemical regulation which resembles that found in non-diabetics. It has not been proved whether this marginal regulation influences the well-being, morbidity or mortality of the patients. In critically ill patients or patients with concurrent diseases, the GIK regime is recommended as this provides optimal regulation of the diabetes. In the remaining patients, local conditions will influence the choice of form of treatment.

Anesthesia↗
PubMed1991

A time-dependent study of passive esophageal wall properties and collagen content in rabbits with esophageal varices.

The passive biomechanical wall properties of the esophagus were studied in rabbits with esophageal varices and controls using a four-electrode impedance technique. Stepwise pressure inflation and deflation was done for analysis of esophageal cross-sectional area, compliance, and hysteresis monthly during six months. At sacrifice, the esophageal collagen content was determined. A small but statistically insignificant increase in compliance was observed during the six-month observation period in both groups. No differences were observed between the groups (P greater than 0.3). No change in hysteresis was observed in either group. The group with esophageal varices had significantly higher collagen content in the distal esophagus when compared to controls (P less than 0.05). No difference was demonstrated in the proximal part. No correlation was demonstrated between the collagen content and esophageal compliance. The study demonstrated that the method allows measurement of luminal cross-sectional area and tissue elasticity. No relationship was found, however, between the collagen content and compliance of the rabbit esophagus.

Animals↗
PubMed1991

Effect of labetalol on cerebral blood flow and middle cerebral arterial flow velocity in healthy volunteers.

The effect of labetalol, a combined alpha- and beta-adrenoceptor antagonist, on the cerebral circulation was investigated in 7 normotensive subjects. Cerebral blood flow (CBF) was measured with the intravenous 133Xe method and mean flow velocity (Vmean) in the middle cerebral artery was determined using transcranial Doppler (TCD) ultrasound. Examination was performed before and then 15, 60 and 120 min after 0.75 mg/kg i.v. labetalol. Reactivity to inhalation of 5% CO2 in air was studied before, and again 90 min after labetalol administration. Neither CBF nor Vmean changed following labetalol administration, whereas a marked increase occurred during inhalation of CO2. The median CO2 reactivity was 3.2%/mmHg (range: 1.8-4.0) for CBF and 4.4%/mmHg (1.5-5.6) for Vmean. These results indicate that labetalol, given in moderate but clinically relevant doses, does not affect the cerebral circulation in normotensive subjects. Neither does it affect CO2 reactivity. The uniform results obtained with the two methods suggest TCD as a usable alternative to conventional CBF technique in the assessment of cerebral vasoactivity of various drugs in subjects with a normal cerebral circulation.

Adult↗
PubMed1991

Effects of flumazenil on cerebral blood flow and oxygen consumption after midazolam anaesthesia for craniotomy.

Cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRO2) were measured by a modification of the Kety-Schmidt technique using i.v. xenon-133 in 20 patients undergoing craniotomy for supratentorial cerebral tumours. Anaesthesia was induced and maintained with midazolam, fentanyl and nitrous oxide. Pancuronium was given for neuromuscular block. The lungs were ventilated to normocapnia. The first flow measurements were performed approximately 1 h after induction of anaesthesia. At the end of operation the patients were allocated to two groups. Ten patients were given flumazenil 0.01 mg kg-1 and 5 min later the second flow measurement was performed. In the other 10 patients the second flow measurement was performed before the administration of flumazenil. Plasma concentrations of midazolam were measured at the time of each measurement of CBF. There was no difference between the groups in plasma concentration of midazolam, CBF or CMRO2. Flumazenil had no effect on CBF and CMRO2.

Adult↗
PubMed1991

Impedance measurement in divers during a scuba-diving training programme.

An assessment of the strain on the tympanic membrane caused by diving was performed using impedance measurement of the middle ear in 21 untrained young men going through a scuba-diving training programme (scuba, self-contained under-water breathing apparatus). Tympanometry was carried out just before and after diving. The divers made 104 dives between them (median 5 each, range 2-7) at depths from 2 to 12 m (median 6 m). The results showed a significant increase in middle ear compliance on diving. The increase in compliance was significant at different depths, was transient, and fell to the initial level between the dives. We conclude that the strain exerted on the tympanic membrane and middle ear from barotrauma due to diving results in a reversible impairment of the recoiling capacity of the elastic fibrils of the tympanic membrane. This transient increase in compliance, we think, is the first measurable change in elasticity of the tympanic membrane. If barotrauma continue the changes could be irreversible.

Acoustic Impedance Tests↗
PubMed1991

Acute and chronic pain syndromes in multiple sclerosis.

A representative sample of 117 patients with definite multiple sclerosis (MS) was interviewed on pain syndromes. Chronic syndromes lasting more than one month included dysaestesthesia, low back pain, spasms, tonic seizures, tightening and painful sensations in the extremities. Acute syndromes included neuralgia, L'Hermitte's sign and pain associated with optic neuritis. Thirty-five per cent were pain-free. Of the remaining patients had 45% pain at the time of the examination, 32% indicated pain among the most severe symptoms of MS and 23% had pain at the onset of MS. The number of patients with pain at the time of the examination increased with age and duration of disease. Patients with pain were significantly more often spastic and significantly more often sought alternative treatment forms. No difference was found for mean age, sex, physical impairment, duration of disease from onset of MS, depressive score and score of delayed verbal memory.

Acute Disease↗
PubMed1991

Multiple sclerosis: the impact of physical impairment and cognitive dysfunction on social and sparetime activities.

In a cross-sectional investigation of 116 patients with multiple sclerosis, the social and sparetime activities of the patient were assessed by both patient and his/her family. The assessments were correlated to physical disability which showed that particularly those who were moderately disabled suffered from severe psychosocial strain. The literature shows that the strain becomes even more severe in certain periods of progression of the disease with the result that psychosomatic conditions arise.

Activities of Daily Living↗
PubMed1991

Measurement of cerebral blood flow (CBF) with the Kety and Schmidt technique during craniotomy.

In this study cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) were measured twice during craniotomy for supratentorial cerebral tumors by the Kety and Schmidt technique. The anaesthetic procedures included halothane, enflurane isoflurane and continuous infusion with midazolam, etomidate, althesin and neurolept anaesthesia (dehydrobenzpyridol). Moderate hypocapnia was used and the anaesthesia was supplemented with nitrous oxide and fentanyl. In general, both CBF and CMRO2 were decreased. However, with inhalation anaesthetics an increase in concentration resulted in an increase in CBF (halothane) or unchanged CBF (isoflurane and enflurane) and a decrease in CMRO2. With the hypnotic agents a dose related decrease in CMRO2 was observed, while CBF either was unchanged (midazolam) or decreased (Althesin and etomidate).

Adult↗
PubMed1991

[Disseminated sclerosis: organic basis for mental disorders and cognitive dysfunction].

The MRI-(magnetic resonance imaging) scanner has improved the knowledge of the organic basis of cognitive defects in multiple sclerosis. Recent studies demonstrated a correlation of MRI-verified single lesions, atrophy of the corpus callosum and cognitive defects; but failed to demonstrate the convincing correlation between psychic symptoms and MRI-verified lesions.

Atrophy↗
PubMed1990

[Hemodynamic assessment of cerebrovascular circulation using transcranial Doppler ultrasound in patients with carotid stenosis].

Transcranial Doppler-ultrasound (TCD) is a new non-invasive technique which renders continuous monitoring of the rate of flow in the major intracerebral arteries possible. The method appears, therefore, to be attractive for perioperative monitoring of patients submitted to operation on account of carotid stenosis. Seventeen patients were included in this preliminary investigation. These patients were submitted for thromboarterectomy of the internal carotid artery. Preoperatively the average flow rate (Vmean) in the ipsilateral medial cerebral artery measured at rest was 54 cm/second (range 34-94) as compared with 57 cm/second (range 32-86) in the contralateral medial cerebral artery. During occlusion, Vmean in the ipsilateral medial cerebral artery decreased momentarily, on an average 35% (p less than 0.001), and returned to the preoperative level after reopening of the internal carotid artery. Corresponding but no significant changes were observed in the pulsatile index. The preliminary experience suggests that TCD is scarcely useful as a diagnostic method in individual cases but that it is well suited for continuous monitoring of changes in cerebral circulating during surgery on the internal cerebral artery. Further assessment of the technique is necessary before the method can be employed routinely, mainly on account of the great interindividual scatter.

Aged↗
PubMed1990

Hysterectomy subsequent to laparoscopic sterilization.

The incidence of hysterectomy for bleeding disorders among sterilized women was compared with the incidence of hysterectomy for bleeding disorders among the female population of the same age in Denmark. The relative risk of undergoing hysterectomy subsequent to tubal sterilization was increased compared to the control group. However, there are several other plausible explanations for this apparently increased risk.

Adult↗