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Biomedical subjects

C Strömberg

Publications and source records attributed to C Strömberg.

15 recordsLinked to original sources
PubMed1992

Exercise alters the pharmacokinetics of midazolam.

Six healthy volunteers received 15 mg midazolam, 50 mg ephedrine, or placebo orally before a 50-minute aerobic treadmill exercise and in a control session. Plasma drug concentrations for pharmacokinetic calculations were estimated from samples drawn up to 24 hours after drug intake. Heart rate, blood pressure, critical flicker fusion test, Maddox wing test, and visual analog scales relating to mood and feelings of tiredness were included in the sessions as pharmacodynamic measures. These tests were made at 35, 55, and 75 minutes and at 2, 2 1/2, 3 1/2, and 5 hours after drug intake. Exercise impaired the absorption of midazolam and counteracted the midazolam-induced decrement in flicker fusion threshold. Whether the effect on flicker fusion was caused mainly by the pharmacokinetic changes or by a general alerting effect of exercise cannot be verified by this experiment. The kinetics of ephedrine was not affected by exercise, but exercise enhanced the tachycardic response to ephedrine and abolished its pressor effect.

Adult↗
PubMed1992

Biosynthetic human growth hormone preserves both muscle protein synthesis and the decrease in muscle-free glutamine, and improves whole-body nitrogen economy after operation.

As a reproducible human trauma model, patients (n = 17) undergoing elective cholecystectomy were studied for 3 postoperative days. They were randomly allocated to receive either recombinant human growth hormone (hGH; 0.3 U/kg/24 hours) or placebo together with total parenteral nutrition, including 0.2 gN/kg/24 hours and 135 kJ/kg/24 hours. Before operation and on the third postoperative day, percutaneous muscle biopsies were performed to determine the concentration and size distribution of ribosomes and the free amino acid concentrations. The significant postoperative decrease in the total ribosome concentration (15.3 +/- 6.4%) and the polyribosome concentration (20.9 +/- 6.5%) in the control group was impeded in the group receiving synthetic hGH. Muscle free glutamine decreased by 35.6 +/- 4.2% in the control group and to a lesser extent in the group that was given hGH after operation (p less than 0.05). The protein content of skeletal muscle was unchanged. The cumulated nitrogen balance for the study period was negative in the control group (-7.09 +/- 0.71 gN), but was not different from zero in the hGH group (-2.32 +/- 1.66 gN). It is concluded that synthetic hGH administered after operation has beneficial effects on the whole-body nitrogen economy, as indicated by the unchanged capacity for protein synthesis in skeletal muscle, the preserved levels of muscle free glutamine, and improvement in the whole-body nitrogen balance. The effects of hGH on skeletal muscle protein and amino acid metabolism can explain the postoperative nitrogen-sparing effect attributed to hGH.

Adult↗
PubMed1992

Angiotensin AT2 receptors regulate cerebral blood flow in rats.

LARGE cerebral arteries have been reported to contain angiotensin receptors that are exclusively of the AT2 subtype. We measured the effect of the AT2 receptor selective ligand PD 123319 on cerebral blood flow (CBF) in rats, using laser-doppler flowmetry. PD 123319 (1-10 mg kg-1) dose-dependently inhibited the increase in CBF, when the blood pressure was increased by a norepinephrine infusion. However, PD 123319 did not alter baseline CBF at normal blood pressures. Therefore PD 123319 appears to interfere with the autoregulatory mechanisms of CBF. The participation of AT2 receptors in the regulation of CBF confirms a physiological role for this receptor subtype, and may give clues for future treatment of various cerebrovascular disorders.

Angiotensin II↗
PubMed1992

Balloon angioplasty enhances the expression of angiotensin II AT1 receptors in neointima of rat aorta.

Angiotensin II is a vasoactive peptide and may act as a growth factor in vascular smooth muscle cells. Experimental injury of the rat aorta causes rapid migration of medial smooth muscle cells and their proliferation resulting in the formation of neointima. We have examined, using quantitative autoradiography, the expression of angiotensin II receptor subtypes AT1 and AT2, and angiotensin-converting enzyme, in the neointima formed in the rat thoracic aorta 15 d after balloon-catheter injury. In contrast to the normal aortic wall, which contained both AT1 and AT2 receptors (80% and 20%, respectively), neointimal cells expressed almost exclusively angiotensin II AT1 receptors. The apparent number of these receptors was fourfold higher in the neointima compared to that in the normal aortic wall. The affinities of the neointimal receptors to angiotensin II or to the AT1 receptor antagonist, losartan, were not different from those in the normal aortic wall. Angiotensin-converting enzyme binding in the neointima was not different from that in the media of the uninjured aorta. Our data suggest that angiotensin II AT1 receptors may have a significant role in injury-induced vascular smooth muscle proliferation and migration.

Angioplasty, Balloon↗
PubMed1992

Prognostic importance of the DNA ploidy pattern in malignant mesothelioma of the pleura.

Malignant mesotheliomas often raise a difficult diagnostic problem: once the diagnosis is made, the possibilities of predicting the biologic activity and prognosis of the tumor are limited. DNA ploidy patterns have been used as a prognostic instrument for other tumors, and this pattern was therefore studied in 37 cases of verified mesothelioma. The measurements were made on Feulgen-stained smears from pleural effusions using a Leica Miamed computer microscope. When a highly aneuploid tumor was defined as a condition with greater than 5% of the cells within defined intervals outside the ranges of the stem-line and the peaks representing polyploidization thereof, a near-diploid/polyploid pattern was obtained in 41% of the cases, while the remaining 59% were classified as highly aneuploid. The prognosis was significantly better among the near-diploid/polyploid cases. This estimate of the outcome could not be improved by using alternative algorithms for high-grade aneuploidy.

Aneuploidy↗
PubMed1991

Angiotensin II AT1 receptors in rat superior cervical ganglia: characterization and stimulation of phosphoinositide hydrolysis.

Angiotensin II receptor number was higher in superior cervical ganglia of 2-week-old when compared to 8-week-old rats. In both young and adult rats, specific binding of [125I][Sar1]angiotensin II was displaced competitively by the AT1-receptor antagonist DuP 753 but not by the AT2-receptor competitor PD 123177. In ganglia from adult rats, DuP 753 competed with an IC50 of 113 nM. The stable guanine nucleotide GTP gamma S inhibited binding of [125I][Sar1]angiotensin II in young and adult rats by approximately 50% with IC50 values of 105 and 120 nM, respectively, suggesting that the angiotensin receptor is G-protein linked. Angiotensin II at a dose of 1 microM stimulated inositol phosphate formation 58% over control values in superior cervical ganglia from 8-week-old rats. This effect was totally blocked by 10 microM DuP 753 but not by 10 microM PD 123177. Our findings demonstrate that rat superior cervical ganglia contain AT1-type angiotensin receptors that are probably G-protein linked, and their stimulation results in increased inositol phospholipid metabolism.

Angiotensin II↗
PubMed1991

Type-1 and type-2 angiotensin II receptors in fetal rat brain.

Brain angiotensin II receptors were located in 18-day-old rat embryos by quantitative autoradiography. In the nucleus of the solitary tract and choroid plexus, binding was displaced by the type-1 antagonist DuP 753. In the inferior olive, paratrigeminal and hypoglossal nuclei, binding was displaced by the type-2 antagonist CGP 42112 A. Meninges and cephalic soft tissues contained predominantly type-2 angiotensin II receptors. Our results indicate a role for type-1 and type-2 angiotensin II receptors during brain development.

Angiotensin II↗
PubMed1991

Echocardiographic and psychometric effects of amitriptyline or imipramine plus alcohol.

The echocardiographic and psychometric effects of amitriptyline or imipramine combined with alcohol have been studied in a double-blind cross-over trial in 7 healthy volunteers. Amitriptyline or imipramine 25 mg b.d. were given for three days and then the dose was doubled. On Days 1 and 10-13 echocardiographic measurements were done, and on Day 15 psychomotor tests were performed. Ethanol 1 g/kg in each session was administered 1 h after drug intake. Alcohol alone increased heart rate and decreased the systolic blood pressure and ejection fraction. It also impaired most of the psychomotor measures, horizontal nystagmus being the most sensitive test. On Day 1, the first dose of imipramine decreased the heart rate and increased diastolic blood pressure. These effects were partly counteracted by alcohol. Imipramine + alcohol decreased the WSTR. Amitriptyline alone did not affect the echocardiographic findings on Day 1. In combination with alcohol it reduced cardiac output and prolonged PEP, and increased the PEP/LVET ratio. During subacute treatment (Days 10-13) WSTR was increased by both antidepressants, but only amitriptyline increased the heart rate. Unlike imipramine + alcohol, amitriptyline + alcohol decreased WSTR and MCSR. Digit symbol substitution was the only pschometric test in which the alcohol effect was clearly enhanced by both amitriptyline and imipramine.

Administration, Oral↗
PubMed1991

Angiotensin-II receptor subtypes in fetal tissue of the rat: autoradiography, guanine nucleotide sensitivity, and association with phosphoinositide hydrolysis.

Quantitative autoradiography revealed large numbers of angiotensin-II (AT) receptors in the 18-day-old rat embryo. The selective AT-1 antagonist DuP 753 readily competed for AT receptors in liver, lung parenchyma, and choroid plexus, and these receptors are classified as AT-1 receptors. The selective AT-2 displacers CGP 42112 A and/or PD 123177 competed with high affinity with AT bound to most receptors located in skeletal muscle, skin, diaphragm, bronchi, and stomach, and these receptors are classified as AT-2 receptors. The amount of AT-2 receptors in fetal tissue was more than 10-fold higher than that of AT-1 receptors. In skeletal muscle and skin, DuP 753 competed with AT in the presence of 10(-7) M CGP 42112 A, indicating the presence of small numbers of AT-1 receptors. In liver and lung parenchyma, binding to AT-1 receptors was sensitive to guanine nucleotides. AT binding to AT-2 receptors in fetal skin and skeletal muscle was insensitive to guanine nucleotides. AT stimulated phosphoinositide hydrolysis in liver (ED50, 64 nM) and in skin and skeletal muscle (ED50, 62 nM); this was inhibited by DuP 753 (liver IC50, 38 nM; skin and skeletal muscle IC50, 26 nM), but not by PD 123177 in concentrations up to the micromolar range. AT-1 receptors are probably coupled to G-proteins, and their stimulation increases phosphoinositide hydrolysis. AT-2 receptors may not be linked to G-proteins, their stimulation is not associated with phosphoinositide hydrolysis, and the nature of their second messenger system(s) is presently unknown.

Angiotensin I↗
PubMed1989

Saving money with effective in-line filters.

The Intensive care unit at Umeå Regional Hospital has during the past year, 1988, used PALL ELD 96 inline-filters on all patients with a central venous catheter. Two different time-periods were investigated, one when inline-filters were used and one without in-line filters. By counting the amount of intravenous disposables that were used and with TISS registration (therapeutic intervention scoring system) which is registered daily on all patients, cost and savings were derived 'per occupied bed day'. The study shows that through using in-line filters which are changed every 96 hours we may save approximately 35,000 pounds every year.

Catheterization, Central Venous↗
PubMed1989

Multicenter clinical trials and their value in assessing total joint arthroplasty.

Multicenter clinical trials (MCT) have an important role in the assessment of total joint arthroplasty. The primary reason for such MCT is the need to have access to a large number of patients. In Sweden, failure after total hip arthroplasty has been recorded prospectively since 1979. Medical records from every reoperation are documented and computer analyzed. This MCT has shown that patient-related, surgical, and implant-related parameters are of importance to rates of failure. There were an increasing number of revisions after total hip arthroplasty in Sweden between 1979 and 1986. Male gender and young age increase the risk of revision. The primary diagnosis is very important for type of failure. The risk of deep infection is small but increases with the number of previous operations. Aseptic loosening has emerged as the main problem and is the cause for 74% of all revisions. Prosthetic design is of utmost importance for the rate of failure, and significant differences exist among different prosthesis types with respect to long-term survival. Finally, this MCT has shown that revisions for total hip arthroplasty in patients younger than 70 years of age eventually have failed in Sweden whenever the cemented technique has been used.

Aged↗
PubMed1987

Acute and subchronic effects of Org 2305 and diazepam on psychomotor performance in man.

Three doses (15, 30 and 60 mg) of Org 2305 (O 15, O 30 and O 60 respectively), a novel anxiolytic drug chemically related to mianserin, were compared with placebo and 15 mg diazepam (DZ) on human psychomotor performance in a double-blind, cross-over study with 15 healthy volunteers. Objective measurements (choice reaction, tracking, flicker fusion, Maddox wing, digit symbol substitution, memory recall) and subjective assessments (visual analogue scales) were done at baseline and 2 and 13 h after the first dose. This testing procedure was repeated on day 7 when administering the seventh consecutive daily night-time dose. After the first dose O 15 did not differ from placebo and O 30 rarely differed from placebo. O 60 impaired various objective functions similarly to, or less than DZ. Subjectively, DZ and O 60 were felt as sedative. During subchronic treatment, DZ caused some impairment of baseline due to accumulation of bioassayable benzodiazepines, but significant responses to the last DZ dose were less than those to the first dose. DZ but not O 60 was reported to have caused lethargy and clumsiness during subchronic treatment. In the doses used Org 2305 impaired psychomotor performance less than diazepam did. A dose of 60 mg Org 2305 may offer some advantage over 15 mg diazepam, provided that their anxiolytic effects are about similar.

Adult↗
PubMedDate not supplied

Characterization of angiotensin II receptor subtypes in the rat spleen.

Quantitative autoradiography was used to determine the subtype of ANG receptors in the red pulp of the rat spleen. The AT1 antagonist DuP 753 competed for ANG binding with high affinity; binding was abolished by dithiothreitol. The AT2 competitor CGP 42112 A showed lower affinity, and the AT2 competitor PD 123177 did not affect binding at 10(-5) M. These data indicated the presence of only AT1 receptors. AT1 receptor number was similar in immature (2 weeks old) and adult (8 weeks old) rats. Binding was sensitive to guanine nucleotides, suggesting an association with G-proteins. Angiotensin II, at a dose of 10(-7) M, stimulated inositol phosphate formation 33% over control values in spleen from 8-week-old rats. This effect was significantly blocked by 10(-5) M DuP 753. We suggest a possible role of AT1 receptors in the regulation of splenic volume, blood flow, and lymphocyte function.

Angiotensin II↗
PubMedDate not supplied

Acute effects of maprotiline, doxepin and zimeldine with alcohol in healthy volunteers.

In a double-blind and cross-over trial, 12 healthy volunteers received single oral doses of maprotiline 75 mg, doxepin 25 mg, zimeldine 200 mg and placebo, alone and with alcohol (1 g/kg), at one-week intervals. Objective tests of performance (tracking, choice reaction, flicker fusion, body sway, nystagmus, Maddox wing) and ratings of subjective feelings were done before the drug intake (baseline) and 1 1/2, 3, 4 1/2, 6 and 7 1/2 hr after it. Maprotiline and doxepin proved subjectively sedative, whilst doxepin and zimeldine prolonged choice reaction time. An increase of alcohol effects was seen clearly after doxepin, to lesser extent after maprotiline and not at all after zimeldine. On the contrary, zimeldine antagonized alcohol-induced impairment in the tracking test.

Adult↗