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P Knudsen

Publications and source records attributed to P Knudsen.

At least 19 recordsLinked to original sources
PubMed2000

[Telepathology at the Norwegian Radium Hospital].

BACKGROUND: The article gives an overview of the telepathology activity at the Norwegian Radium Hospital from the service was launched in 1994 and up until today. We show the development during these years and discuss telepathology in general terms. We also discuss those aspects that determine how well a telepathology service functions. MATERIAL AND METHODS: 74 frozen section slides were diagnosed by two different telepathology systems. One of these systems was used for examining its appropriateness as a tool for second opinion in pathology. A new Internet-based system was developed that provided additional functionality. RESULTS: A telepathology system with a digital camera outperforms one with an analog camera with respect to diagnostic accuracy. INTERPRETATION: Image quality determines the precision of a telepathology service. Telepathology is a feasible tool for second opinion in pathology.

Diagnosis, Computer-Assisted↗
PubMed1999

Delayed clearance of postprandial large TG-rich particles in normolipidemic carriers of LPL Asn291Ser gene variant.

The carrier frequency of Asn291Ser polymorphism of the lipoprotein lipase (LPL) gene is 4;-6% in the Western population. Heterozygotes are prone to fasting hypertriglyceridemia and low high density lipoprotein (HDL) cholesterol concentrations especially when secondary factors are superimposed on the genetic defect. We studied the LPL Asn291Ser gene variant as a modulator of postprandial lipemia in heterozygote carriers. Ten normolipidemic carriers were compared to ten control subjects, who were selected to have similar age, sex, BMI, and apolipoprotein (apo)E-phenotype. The subjects were given a lipid-rich mixed meal and their insulin sensitivity was determined by euglycemic hyperinsulinemic clamp technique. The two groups had comparable fasting triglycerides and glucose utilization rate during insulin infusion, but fasting HDL cholesterol was lower in carriers (1.25 +/- 0.05 mmol/L) than in the control subjects (1. 53 +/- 0.06 mmol/L, P = 0.005). In the postprandial state the most pronounced differences were found in the very low density lipoprotein 1 (VLDL1) fraction, where the carriers displayed higher responses of apoB-48 area under the curve (AUC), apoB-100 AUC, triglyceride AUC, and retinyl ester AUC than the control subjects. The most marked differences in apoB-48 and apoB-100 concentrations were observed late in the postprandial period (9 and 12 h), demonstrating delayed clearance of triglyceride-rich particles of both hepatic and intestinal origin. Postprandially, the carriers exhibited enrichment of triglycerides in HDL fraction. Thus, in normolipidemic carriers the LPL Asn291Ser gene variant delays postprandial triglyceride, apoB-48, apoB-100, and retinyl ester metabolism in VLDL1 fraction and alters postprandial HDL composition compared to matched non-carriers.

Adult↗
PubMed1998

Genetic variation in the amino-terminal part of apolipoprotein B: studies in hyperlipidemic patients.

Hypertriglyceridemia is a heterogeneous lipid disorder often running in families. Variation in the apolipoprotein B (apo B) gene has been associated with serum triglyceride levels. Recently, a role of the amino-terminal end of apo B in binding with lipoprotein lipase (LPL) has been suggested. We screened the 5' end of the apo B gene in 76 Finnish severely hypertriglyceridemic (> 6 mmol/l) patients, using a single-strand conformation polymorphism (SSCP) screening method. We detected a previously unreported polymorphic C2316-->A change, causing a Val703-->Ile substitution. The minor 703 Ile allele frequency was 0.04 in hypercholesterolemic and normolipidemic population samples. This allele was associated with lower serum triglyceride levels in a normolipidemic population sample. Analysis of two previously reported polymorphisms also located in the amino-terminal domain of apo B (Thr71-->Ile and Val591-->Ala) revealed elevating effects on serum apo B concentrations in hypertriglyceridemic individuals. The 591 Ala allele was associated with elevated apo B (P=0.011), and individuals with both minor alleles (apo B 591 Ala + and apo B 71 Ile +) had higher apo B levels compared to subjects homozygous for both common alleles (P=0.004). Although no DNA sequence change seemed to be the cause of hypertriglyceridemia in our patients, genetic variation in the 5' end of the apo B gene may contribute to changes in serum apo B levels in hypertriglyceridemic patients.

Adult↗
PubMed1997

Heterozygous hepatic lipase deficiency, due to two missense mutations R186H and L334F, in the HL gene.

Hepatic lipase (HL) is an endothelial enzyme involved in the metabolism of intermediate density lipoproteins (IDL) and high density lipoproteins (HDL) in plasma. In a Finnish pedigree consisting of 18 members belonging to three generations two missense mutations RI86H and L334F in exons 5 and 7 of the HL gene co-segregated with low post-heparin HL activity. Haplotype analysis of the HL gene in family members revealed a high degree of genetic variation and demonstrated that the two missense mutations reside on the same chromosome. In vitro site-directed mutagenesis and expression of the cDNA constructs in COS-1 cells revealed that the R186H mutation leads to a protein that is not secreted while the L334F mutation results in the production of a HL protein that is secreted but has only about 30% of wild type HL activity. Carriers of the mutated HL gene exhibited clearly reduced HL activity and mass in post-heparin plasma. Probably due to their heterozygous carrier status they had only moderate elevation of total triglycerides, IDL, and LDL-triglycerides. The LDL-particles were enriched in triglycerides and depleted of cholesterol. Also their HDL2- and HDL3-particles were enriched in triglycerides.

Adolescent↗
PubMed1997

The Asn-291-->Ser and Ser-477-->Stop mutations of the lipoprotein lipase gene and their significance for lipid metabolism in patients with hypertriglyceridaemia.

We examined 99 Finnish patients whose serum fasting triglycerides (TG) had exceeded 6.0 mmol L-1 with special interest to their lipid, lipoprotein and post-heparin plasma lipase activities. The control group consisted of 75 healthy individuals. We also determined the frequency of the Asn-291-->Ser and Ser-447-->Stop mutations both in hypertriglyceridaemic (HTG) subjects and in control subjects. A total of 51 of the original 99 hypertriglyceridaemic patients still had TG > 6.0 mmol L-1 when measured a second time. They are referred to as persistently hypertriglyceridaemic subjects (pHTG). The remaining 48 subjects had TG < 6.0 mmol L-1 in the second measurement and are referred to as sporadically hypertriglyceridaemic subjects (sHTG). The allelic frequencies of the Ser-447-->Stop mutation in the total HTG and sHTG groups were similar to the frequencies present in the control group, but lower in pHTG patients compared with the control group (0.049 vs. 0.153, chi(2) = 6.63, P < 0.05). The Asn-291-->Ser mutation was more frequent in HTG group than in the control group (0.0606 vs. 0.013, chi(2) = 4.86, P < 0.05). This difference was due to the higher frequency of the minor allele of Asn-291-->Ser in the cohort with persistent hypertriglyceridaemia compared with the control group (0.088 vs. 0.013, chi(2) = 8.00, P < 0.01). The highest frequency (0.114) of the minor allele of Asn-291-->Ser was found in type 2 diabetic patients with persistent hypertriglyceridaemia. The carrier status of Asn-291-->Ser or Ser-447-->Stop did not predict either post-heparin plasma lipoprotein lipase (LPL) activities or lipid and lipoprotein levels in any of the groups studied. Our data suggest that overproduction of very low-density lipoproteins (VLDL) is a more important cause of hypertriglyceridaemia in the Finns than is the LPL deficiency.

Adult↗
PubMed1997

Duration of postoperative pneumoperitoneum.

OBJECTIVE: To find out the duration of postoperative pneumoperitoneum and the factors that are responsible for its persistence. DESIGN: Prospective open (non-random) study. SETTING: County hospital, Denmark. SUBJECTS: 32 patients over 18 years of age undergoing abdominal operations during a 6 month period. INTERVENTIONS: Abdominal radiographs with the patient in the left lateral position were taken at fixed time intervals until no free air could be seen. MAIN OUTCOME MEASURES: The amount of free air and the time postoperatively by which it had disappeared. RESULTS: In 20 [corrected] patients the air had disappeared within 48 hours and only one patient (3%) had free air for more than five days postoperatively. High body mass index and a small initial amount of free air were associated with the shortest period of postoperative pneumoperitoneum. CONCLUSION: Postoperative pneumoperitoneum disappeared within two days in most patients. Heavier patients and patients with small volumes of free air initially had the shortest duration of pneumoperitoneum. There were large variations among patients in the volumes of free air.

Abdomen↗
PubMed1996

Polymorphism of the glycogen synthase gene in hypertensive and normotensive subjects.

Hypertension and non-insulin-dependent diabetes mellitus (NIDDM) are characterized by a strong genetic component and impaired ability to store glucose as glycogen in skeletal muscle. Impaired insulin activation and altered genetic control of muscle glycogen synthase, the rate-limiting enzyme for glucose storage in skeletal muscle, could provide an explanation for this insulin resistance. We examined whether there is an association between the glycogen synthase gene (Xba I polymorphism) and hypertension in 304 nondiabetic subjects. We examined glucose tolerance with an oral glucose tolerance test and glucose storage in skeletal muscle with the euglycemic insulin clamp technique in combination with indirect calorimetry. The Xba I A2 allele of the glycogen synthase gene was enriched in subjects with hypertension and a family history of NIDDM (48%) compared with normotensive subjects without a family history of NIDDM (6%, P < .0001). The presence of the A2 versus the A1 allele was associated with decreased rates of insulin-stimulated glucose storage in hypertensive subjects (11.2 +/- 2.3 versus 16.9 +/- 2.6 mumol/kg lean body mass per minute, P = .029) but not in normotensive subjects (28.0 +/- 4.6 versus 29.6 +/- 3.7 mumol/kg lean body mass per minute). In conclusion, Xba I polymorphism of the glycogen synthase gene identifies a subgroup of hypertensive subjects with a family history of NIDDM. The data suggest that a locus in the glycogen synthase gene region on chromosome 19 may serve as a "thrifty gene," increasing susceptibility for insulin resistance when exposed to other environmental or genetic factors.

Adult↗
PubMed1996

A compound heterozygote for hepatic lipase gene mutations Leu334-->Phe and Thr383-->Met: correlation between hepatic lipase activity and phenotypic expression.

We have characterized the molecular basis for familial hepatic lipase (HL) deficiency in a Finnish family. In the propositus, the HL deficiency results from compound heterozygosity for two rare HL gene mutations, a previously unknown missense mutation designated L334F and the previously reported T383M mutation. These mutations were introduced into human HL cDNA by site-directed mutagenesis and the constructs expressed in COS-1 cells. In the homogenate of COS-1 cell transfected with the L334F mutant cDNA, a high amount of inactive protein accumulated. In the media of L334F transfected cells, 30% of the wild type activity and 80% of wild type mass were detected. The lysates of COS-1 cells transfected with the T383M mutant cDNA contained 39% of wild type HL activity and 34% of wild type HL mass. In the media of COS-1 cells transfected with the T383M cDNA construct, 50% of wild type HL mass but only 6% of wild type activity was present. The single amino acid substitutions present in L334F and T383M are therefore sufficient to severely affect the HL enzyme. These defects explain the HL-deficient phenotype of the individual carrying the two mutations. The lipoprotein phenotype associated with compound heterozygosity for L334F and T383M mutations is characterized by a slight increase in the buoyant low density lipoprotein (LDL) fraction and an increase in the light high density lipoprotein (HDL) fractions, HDL2a and HDL2b. These results demonstrate that lipoprotein changes occurring in HL deficiency are difficult to identify and support the hypothesis that HL is important in HDL remodeling and metabolism in vivo.

Adult↗
PubMed1996

Hyperinsulinemia and insulin resistance are associated with multiple abnormalities of lipoprotein subclasses in glucose-tolerant relatives of NIDDM patients. Botnia Study Group.

We studied the subclasses of plasma lipoproteins in normolipidemic, glucose-tolerant male relatives of noninsulin dependent diabetic patients (NIDDM), who represented either the lowest (n = 14) or the highest (n = 18) quintiles of fasting plasma insulin. The higher plasma triglyceride level in the high insulin group (1.61 mmol/l vs. 0.87 mmol/l, P < 0.001) was due to multiple differences in triglyceride-rich lipoproteins. The concentrations of larger VLDL1, smaller VLDL2 particles, and IDL particles were 3.8-fold, 2.5-fold, and 1.5-fold higher, respectively, in the high insulin group than in the low insulin group (P < 0.01 or less). In addition, hyperinsulinemic subjects had VLDL1, VLDL2, and IDL particles enriched in lipids and poor in protein. The lower plasma HDL cholesterol level in the high insulin group (1.20 mmol/l vs. 1.44 mmol/l, P < 0.01) compared to the low insulin group was a consequence of a 27% reduction of HDL2a concentration (P < 0.05) and a significantly reduced percentage of cholesterol in HDL3a, HDL3b, and HDL3c subclasses. On the other hand, the percentages of triglycerides in HDL2b, HDL2a, HDL3a, and HDL3b subclasses were 76%, 79%, 61%, and 50% higher, respectively, in the high insulin group than in the low insulin group (P < 0.01 or less). In the combined group, the concentration of VLDL1 and VLDL2 correlated positively with the concentrations of LDL2 and LDL3 and negatively with HDL2b and HDL2a subclasses (P < 0.05 or less). In conclusion, normolipidemic, glucose-tolerant but hyperinsulinemic relatives of NIDDM patients have qualitatively similar lipoprotein abnormalities as NIDDM patients. These abnormalities are not observed in insulin-sensitive relatives, suggesting that they develop in concert with insulin resistance.

Adult↗
PubMed1995

Changes of lipolytic enzymes cluster with insulin resistance syndrome. Botnia Study Group.

The activities of hepatic and lipoprotein lipase and the levels of lipo- and apoproteins were compared in two groups of normoglycaemic men representing the highest (n = 18) and lowest (n = 15) fasting insulin quintiles of first degree male relatives of non-insulin-dependent diabetic patients. The high insulin group representing insulin-resistant individuals had significantly lower post-heparin plasma lipoprotein lipase activity than the low insulin group (14.2 +/- 4.0 vs 20 +/- 5.8 mumol NEFA.ml-1.h-1, p < 0.001); hepatic lipase activity did not differ between the two groups (24.2 +/- 11 vs 18.0 +/- 5.3 mumol NEFA.ml-1.h-1, NS). The lipoprotein lipase/hepatic lipase ratio in the high insulin group was decreased by 66% as compared to the low insulin group (0.75 +/- 0.57 vs 1.25 +/- 0.65, p < 0.01). In the high insulin group both total and VLDL triglycerides were higher than in the low insulin group (1.61 +/- 0.57 vs 0.86 +/- 0.26 mmol/l, p < 0.001 and 1.00 +/- 0.47 vs 0.36 +/- 0.16 mmol/l, p < 0.001, respectively) whereas HDL cholesterol and HDL2 cholesterol were lower (1.20 +/- 0.30 vs 1.43 +/- 0.22 mmol/l, p < 0.05 and 0.49 +/- 0.21 vs 0.71 +/- 0.17 mmol/l, p < 0.05, respectively). Total cholesterol, LDL cholesterol or HDL3 cholesterol did not differ between the two groups. The mean particle size of LDL was smaller in the high insulin group than in the low insulin group (258 +/- 7 vs 265 +/- 6 A, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1995

LDL particle size in mildly hypertriglyceridemic subjects: no relation to insulin resistance or diabetes.

We examined 18 Type 2 diabetic and 19 non-diabetic subjects in order to determine the association between insulin resistance and LDL particle size distribution in mildly hypertriglyceridemic and hyperinsulinemic subjects with and without Type 2 diabetes. Insulin sensitivity of the patients was characterized by their insulin-stimulated glucose uptake rate determined by euglycemic clamp technique. LDL particle size distribution was determined by nondenaturing polyacrylamide gradient gel electrophoresis. Type 2 diabetic and non-diabetic subjects had closely similar serum lipid and lipoprotein concentrations as well as the mean particle diameters of the major LDL peak (246 +/- 6 A and 244 +/- 6 A, respectively). To evaluate the effect of insulin resistance on LDL particle size the participants were categorized into two subgroups using the median of their insulin-stimulated glucose uptake rate (14.67 mumol/kg/min) as a cut-off point. Neither lipid and lipoprotein concentrations nor the LDL particle size distributions differed between the more insulin resistant group (nine diabetic and nine non-diabetic subjects) and less insulin resistant group (nine diabetic and ten non-diabetic subjects). LDL particle size was not associated with the insulin-stimulated glucose uptake rate or with the mean 24-h concentration of serum insulin. Mean 24-h concentration of serum triglycerides was the strongest discriminator for LDL particle size (r = -0.44, P < 0.01). In conclusion, neither Type 2 diabetes nor insulin resistance seem to have any direct effect on LDL particle size in mildly hypertriglyceridemic subjects. The fact that LDL particle size was associated with serum triglycerides indicates that the effect of diabetes and insulin resistance on LDL particle size could be explained by the effects of insulin resistance and/or hyperinsulinism on VLDL metabolism.

Blood Glucose↗
PubMed1995

Decreasing triglyceride by gemfibrozil therapy does not affect the glucoregulatory or antilipolytic effect of insulin in nondiabetic subjects with mild hypertriglyceridemia.

We studied the effects of gemfibrozil on glucose and fatty acid metabolism in subjects with mild endogenous hypertriglyceridemia. Twenty subjects (serum triglycerides, 3.2 +/- 1.4 mmol/L; age, 52 +/- 7 years; body mass index, 27.8 +/- 1.8 kg/m2) were randomly allocated to receive either placebo or gemfibrozil 1,200 mg daily for 12 weeks in a double-blind study. Gemfibrozil decreased serum total and very-low-density lipoprotein (VLDL) triglycerides by 53% and 57%, respectively, and serum apolipoprotein (apo) B concentration by 21%. Gemfibrozil had no effect on the diurnal concentration of free fatty acids (FFA). Neither did gemfibrozil change diurnal blood glucose or serum insulin concentrations. The endogenous glucose production rate remained unchanged in both groups during the treatment period, and was similarly suppressed by hyperinsulinemia. The rate of insulin-induced whole-body glucose disposal increased similarly both before (basal 10.8 +/- 1.8, low-dose insulin 10.5 +/- 2.1, and high-dose insulin 20.9 +/- 11.9 mumol.kg-1.min-1) and after (11.1 +/- 1.7, 10.7 +/- 1.2, and 18.6 +/- 7.9, respectively) gemfibrozil treatment. Rates of oxidative and nonoxidative glucose metabolism remained unchanged during gemfibrozil treatment. Basal pretreatment and posttreatment FFA turnover rates were similar in both study groups, as were the rates of substrate oxidation. In summary, gemfibrozil proved to be an effective serum triglyceride-lowering agent in patients with mild hypertriglyceridemia, but had no effect on the insulin sensitivity of glucose metabolism or of antilipolysis. These data support the idea that triglycerides per se do not cause insulin resistance, and that the triglyceride-lowering effect of gemfibrozil is not mediated via antilipolytic action.

Analysis of Variance↗
PubMed1994

Routine use of ultrasound and flexible cystoscopy in the control of benign bladder tumours.

During the period 1987-1992, 99 patients with benign bladder tumours were followed regularly with transabdominal ultrasound of the bladder and out-patient flexible cystoscopy. Thirty-five patients had recurrent bladder tumours, but in only one case was there progression to invasive tumour. Seventy-six per cent of the recurrences were diagnosed by flexible cystoscopy while 22% were found by ultrasound. Compared to conventional follow-up programs with in-patient rigid cystoscopy the combination of ultrasound and flexible cystoscopy proved to be safe, highly acceptable by the patients and cost-effective.

Aged↗
PubMed1992

Antioxidant treatment with N-acetylcysteine during adult respiratory distress syndrome: a prospective, randomized, placebo-controlled study.

OBJECTIVE: To examine whether the antioxidant N-acetylcysteine could ameliorate the course of the adult respiratory distress syndrome (ARDS) in man. DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: Medical and surgical ICU in a regional hospital. PATIENTS: Sixty-six ICU patients with ARDS. INTERVENTIONS: Patients with ARDS (PaO2/FiO2 ratio less than 250 torr) were treated with either the antioxidant N-acetylcysteine 150 mg/kg as a loading dose and then 20 mg/kg/hr, or with placebo for 6 days. MEASUREMENTS AND MAIN RESULTS: No improvement could be demonstrated in the PaO2/FiO2 ratio in the study group as compared with the control group on any day. Pulmonary compliance was higher in the N-acetylcysteine group than in the placebo group on all days, but this difference did not reach the chosen 5% level of significance. No difference between the two groups could be demonstrated on chest radiograph or on survival rate. We documented that N-acetylcysteine acts as an anticoagulant and perhaps decreases pulmonary fibrin uptake during ARDS. CONCLUSIONS: N-acetylcysteine might be of benefit in ARDS. Before further clinical studies are started, problems with N-acetylcysteine and coagulation have to be elucidated in order to find out whether N-acetylcysteine could have a beneficial effect in the treatment of ARDS.

Acetylcysteine↗
PubMed1991

Rapid analysis and quantitation of PCR products by high-performance liquid chromatography.

HPLC utilizing a high efficiency anion-exchange column provides a rapid and easily automated technique for the qualitative and quantitative analysis of subnanogram to microgram amounts of DNA fragments generated by the PCR. The accuracy, precision and linearity of this method exceed those attainable with electrophoretic techniques. In addition, because of the nondestructive nature of HPLC, the desired PCR amplification product can be purified for subsequent utilization. Thus, liquid chromatography extends the utility of the PCR technique to those applications requiring precise quantitation.

Base Sequence↗
PubMed1987

The effect of the tricyclic antidepressant drug, nortriptyline on left ventricular ejection fraction and left ventricular volumes.

Eight patients with major depression but otherwise healthy underwent radionuclide cardiography before and during nortriptyline treatment. The second examination was performed when the nortriptyline plasma concentration was within the therapeutic range (60-150 micrograms X l-1). Heart rate, arterial blood pressure, left ventricular ejection fraction, left ventricular volumes, systolic pressure-volume ratio, and cardiac output were determined. Heart rate increased in mean by 13% (P less than 0.05). All other variables were unchanged. We conclude that nortriptyline in therapeutic doses produces no major adverse effect on left ventricular function. Routine radionuclide cardiography might be a suitable method to detect among those treated with tricyclic antidepressants the occasional susceptible patient. This may particularly apply to patients with known heart disease and to elderly patients.

Adult↗