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Biomedical subjects

T Karlsson

Publications and source records attributed to T Karlsson.

At least 145 records · Page 8Linked to original sources
PubMed1994

The appropriateness of performing coronary angiography and coronary artery revascularization in a Swedish population.

OBJECTIVE: To evaluate the appropriateness of performing coronary angiography and revascularization in a Swedish population. DESIGN: Prospective population study of questionnaires and medical records. SETTING: All the hospitals in southwestern Sweden that perform coronary angiography and revascularization. PATIENTS: Random sample of 831 patients (with chronic stable angina) on the waiting list for coronary angiography or revascularization in southwestern Sweden in September 1990. MAIN OUTCOME MEASURE: Percentage of patients referred for coronary angiography or revascularization for appropriate, uncertain, or inappropriate indications. RESULTS: Of the patients referred for angiography, 89% were classified as appropriate, 9% as uncertain, and 2% as inappropriate. The percentages are similar for patients referred for coronary artery bypass graft surgery and for angioplasty (91% and 86%, respectively, classified as appropriate). The majority of patients had chest pain rated as Canadian Cardiovascular Society classes II through IV (93%), despite maximum anti-ischemic therapy in 90% of these patients. CONCLUSIONS: Few patients were referred for coronary angiography or revascularization for inappropriate or uncertain indications. The percentage of these patients who are from southwestern Sweden is similar to the percentage recently reported from New York State.

Adult↗
PubMed1994

Antagonism by SCH 23390 of clozapine-induced hypothermia in the rat.

Clozapine (7.5-30.0 mumol kg-1 s.c.) produced a decrease in core temperature in the rat. The temperature decrease caused by clozapine (7.5 mumol kg-1 s.c.) was fully antagonized by the selective dopamine D1 receptor antagonist SCH 23390 (0.3 mumol kg-1) s.c.) and a partial antagonism was obtained by the selective dopamine D2 receptor antagonist raclopride (1.6 mumol kg-1 s.c.). On the other hand, the hypothermia was not antagonized by alpha-adrenoceptor antagonists (idazoxan and prazosin), 5-HT receptor antagonists ((-)-pindolol and ritanserin) or by the muscarinic M1 receptor antagonist scopolamine. The hyperthermia produced by the 5-HT1C/2 receptor agonist DOI (0.75 mumol kg-1) was blocked by clozapine (3.0 mumol kg-1 s.c.). Clozapine did not antagonize hypothermia produced by selective dopamine D1 and D2 receptor agonists (A 68930 and quinpirole), the alpha 2-adrenoceptor agonist clonidine, the 5-HT1A receptor agonist 8-OH-DPAT (8-hydroxy-2-(di-n-propylamino)tetralin) or the muscarinic M1 receptor agonist oxotremorine. The present results suggest that clozapine may be a partial agonist at brain dopamine D1 receptors.

Amphetamines↗
PubMed1994

The effects of different intravenous feeding regimens on the rates of synthesis of alpha1-antitrypsin after surgery.

The effects of two nutritional regimens on the synthesis of alpha-1 antitrypsin were investigated postoperatively in gynaecological cancer patients. Total parenteral nutrition (TPN) or a hypocaloric amino acid mixture was administered on the day of surgery and continued for 3 days. The rate of synthesis of alpha-1 antitrypsin was estimated by a computer model from serial plasma concentrations of this protein and a reference protein, albumin. The hypocaloric amino acid mixture resulted in a more negative nitrogen balance than that produced during administration of TPN containing the same amount of nitrogen but more non-protein energy. Urinary excretion of 3-methylhistidine was significantly greater (p = 0.017) in the hypocaloric amino acid group (350 +/- 40 mumol/day; mean +/- SE) on the third postoperative day, as compared to the TPN group (240 +/- 20 mumol/day). In spite of this the synthesis of alpha-1 antitrypsin was apparently greater in the hypocaloric amino acid than in the TPN group. The accumulated plasma appearance rate of alpha-1 antitrypsin was significantly higher (p = 0.0465) in HAA group, at 70 h it was 490 +/- 40 compared to 400 +/- 20 times the pre-operative synthesis in the TPN group.

Journal Article↗
PubMed1994

A media campaign aiming at reducing delay times and increasing the use of ambulance in AMI.

To improve the prognosis in patients with acute myocardial infarction (AMI) if treatment by early instituting treatment, we initiated a media campaign during 1 year with the intention to reduce delay times and increase ambulance use in patients with acute chest pain. This article describes the outcome during 3 years after the campaign was finished. The median delay time in patients with AMI was reduced from 3 hours 0 min before the campaign to 2 hours 20 minutes during the year of the campaign (P < .001). The median delay time remained at a similar level (2 hours 20 min) during the 3 years after the campaign. Ambulance use was not affected during or after the campaign. It can be concluded that a media campaign resulted in a reduction of delay times not only during the campaign, but also during 3 years after its performance, whereas ambulance use was not affected.

Acute Disease↗
PubMed1994

Serum triglycerides and HDL cholesterol--major predictors of long-term survival after coronary surgery.

The influence of pre-operative serum lipid levels on late clinical outcome after coronary artery bypass surgery was analysed in 83 patients undergoing coronary bypass surgery for stable angina pectoris. The mean follow-up period for surviving patients was 105 +/- 33 months (range 65-133). Twenty-two patients (27%) had died during follow-up, of whom 14 had sustained a fatal myocardial infarction and four had succumbed to other cardiovascular causes. Thirty-one patients sustained 35 cardiac events, defined as either fatal or non-fatal myocardial infarction, or reoperation, or PTCA during the follow-up period. With univariate analysis, pre-operative serum levels of total cholesterol and triglycerides were significantly related to cardiac events, P < 0.05 and P < 0.05, respectively. In a Cox proportional analysis, cardiac mortality and total mortality were related to serum triglycerides and HDL cholesterol (P < 0.05 and P < 0.01 respectively). Eighty-five percent of the patients with triglycerides < 2.0 mM.l-1 survived for 10 years, while only 48% of patients with triglycerides > 2.0 mM.l-1 remained alive for that period. Figures were similar for subjects with HDL cholesterol > 1.0 mM.l-1 or HDL cholesterol < 1.0 mM.l-1, at 89 and 38%, respectively. Only 28% of the patients with the combination triglycerides > 2.0 mM.l-1 and HDL cholesterol < 1.0 mM.l-1 were alive 10 years after surgery. These data suggest that dyslipidaemia, especially the combination of high serum triglycerides and low HDL cholesterol, is an important factor influencing long-term clinical outcome after coronary bypass surgery.

Angina Pectoris↗
PubMed1994

The epidemiology of a coronary waiting list. A description of all of the patients.

OBJECTIVES: To describe the characteristics and the severity of symptoms amongst patients on the waiting list for possible coronary revascularization. DESIGN: All the patients were sent a postal questionnaire for symptom evaluation. SETTING: All hospitals in western Sweden. SUBJECTS: All patients in western Sweden on the waiting list in September 1990, who had been referred for coronary angiography or revascularization (n = 904) and a sex- and age-matched reference group (n = 809). RESULTS: More than half of the patients had daily attacks of chest pain, whereas 16% reported less than one attack per week or no pain at all. However, other symptoms such as dyspnoea, tachycardia and nervous reactions were also common and 25% of all patients used sedatives. A long waiting time for a given procedure was not associated with more pain but with more nervous symptoms such as restlessness and insomnia (P < 0.0001) and greater use of sedatives and cigarettes (P < 0.05). CONCLUSIONS: We conclude that a long waiting time for possible coronary revascularization is associated with more nervous symptoms but not with more pain.

Adult↗
PubMed1994

Central and regional blood flow during hyperventilation. An experimental study in the pig.

Mechanical hyperventilation not only reduces brain oedema after neurotrauma but also affects the central and systemic circulation. We have, in pigs, measured blood flow in the pulmonary artery, the portal vein and in the femoral artery, as well as estimated the splanchnic blood flow and studied the relative perfusion using the microsphere technique in normo- and hypocarbia during intermittent positive pressure ventilation. A normoventilated control group did not change in cardiac output, portal vein blood flow, splanchnic blood flow and femoral arterial blood flow. Hyperventilation was performed to a PCO2 of 3.0 +/- 0.1 kPa. We found that in pigs ventilated with high tidal volume skeletal muscle blood flow did not change during the first 60 min of hyperventilation but gradually decreased thereafter. Blood flow to the cerebellum decreased soon after the induction of hyperventilation, whereas the cerebral blood flow did not decrease until the second hour of hyperventilation. Cardiac output, splanchnic perfusion and portal vein blood flow all decreased. Myocardial perfusion and arterial blood flow to spleen and kidney decreased while pancreatic and liver arterial blood flows were unaffected. It is concluded that mechanical hyperventilation with low frequency and large tidal volumes reduces the flow to most tissues, where the relative decrease according to microsphere measurements is most pronounced in skeletal muscles, heart muscle and cerebellum. However, the changes in cardiac output and splanchnic blood flow were not observed when hyperventilation was induced by increased frequency, keeping the tidal volume constant.

Animals↗
PubMed1994

Skin sympathetic nerve activity and effector function during sleep in humans.

Multi-unit sympathetic skin nerve activity (SSA) in the peroneal nerve was recorded together with electrical skin resistance, skin blood flow and (in some subjects) finger blood pressure during sleep in 22 sleep-deprived healthy subjects. The average strength of sympathetic activity in different sleep stages was measured during 5-min periods as the area-under-curve of the integrated neurogram. Stage 2 sleep was reached by 15 subjects, stages 3-4 by nine and rapid eye movement (REM) sleep by six subjects. Non-REM sleep was always associated with an increased skin resistance, which was larger in glabrous than in hairy skin (293 +/- 48 vs. 175 +/- 4% of awake control level, n = 10, P < 0.05). Skin blood flow also increased during sleep, with a mean maximal increase of 397 +/- 79% of the awake control level (n = 11, P < 0.05). In spite of these changes of effector function no significant difference in mean SSA was found between the awake control period and periods of non-REM sleep, but during REM sleep SSA increased with 34% (P < 0.05) compared with the immediately preceding stage 2 period. In stage 2 sleep, K-complexes were associated with bursts of SSA followed by transient changes of skin resistance, blood flow and arterial blood pressure. When both skin resistance and blood flow were recorded within the innervation area of the impaled fascicle, single bursts or short periods of increased SSA could be succeeded by increased skin blood flow without concomitant skin resistance change. This indicates the existence of specific sympathetic vasodilator fibres in the skin. Therefore the unchanged strength of multiunit SSA during non-REM sleep in the face of increases of skin resistance and blood flow may be a consequence of an increased sympathetic vasodilator nerve activity combined with decreases of vasoconstrictor and sudomotor traffic.

Adult↗
PubMed1994

Shb is a ubiquitously expressed Src homology 2 protein.

To identify serum-inducible genes in the insulin-producing cell line beta TC-1, a library subtraction screening procedure was performed on serum-deprived (G0) and serum-restimulated (G1) insulin-producing beta TC-1 cells. A cDNA containing a motif with strong homology to Src homology 2 (SH2) domains was found using this procedure and called Shb. The Shb cDNA contains two methionine codons in its N-terminus and thus may code for two proteins of 67 and 56 kDa, each with one SH2 domain in its C-terminus. No other structural similarity to proteins with catalytic activity could be detected, suggesting that Shb is a so called adaptor. Shb contains the proline-rich sequence PPPGPGR between the two proposed initiator methionines which resembles a sequence for binding to Src homology 3 (SH3) domains. A second proline-rich sequence was detected after the second methionine codon. The Shb cDNA hybridized to a similar or identical mRNA of 3.1 kb expressed in mouse brain, liver, kidney, heart, NIH3T3 fibroblasts and beta TC-1 cells. Western blot analysis of the same tissues using an antiserum directed against a synthetic peptide corresponding to a part of the SH2 domain of Shb, revealed reactivity with two proteins of 56 and 67 kDa. In addition, a third reactive component of 40 kDa was detected in most tissues. Transfection and transient expression of the Shb cDNA in COS-1 cells yielded increased expression of the 67, 56 and 40 kDa proteins. Transfection and stable expression of the Shb cDNA in pig aortic endothelial cells showed increased expression primarily of the 67 kDa protein. A fusion protein consisting of the SH2 domain of Shb linked to glutathione S-transferase showed increased binding to glycoproteins of cells stimulated with platelet-derived growth factor (PDGF-BB). Furthermore, the autophosphorylated PDGF beta-receptor but not the autophosphorylated epidermal growth factor (EGF) receptor bound specifically to immobilized fusion protein. It is concluded that Shb is a novel SH2-containing protein with proline-rich domains and therefore probably involved in the signal-transduction of some ligand-activated tyrosine kinase receptors.

Adaptor Proteins, Signal Transducing↗
PubMed1993

Occurrence of hypotension during streptokinase infusion in suspected acute myocardial infarction, and its relation to prognosis and metoprolol therapy.

In all patients who received streptokinase infusion for strongly suspected acute myocardial infarction in 1 hospital during 1989 to 1990, the occurrence of hypotension during infusion is described and related to prognosis. In 54% of patients, the beta blocker metoprolol was simultaneously administered intravenously. The median systolic blood pressure (BP) before infusion was 135 mm Hg, and the median value for the lowest systolic BP recorded during infusion was 100 mm Hg (p < 0.001). A positive correlation between systolic BP before streptokinase and the lowest systolic BP during infusion was found (r = 0.53; p < 0.001). Among patients administered streptokinase and metoprolol, 23% had systolic BP < 90 mm Hg, and 12% had < 80 mm Hg at any time during infusion; corresponding values for patients administered streptokinase only were 47 and 30%, respectively. Patients with the lowest systolic BP < 80 mm Hg during infusion had a mortality during the first 2 weeks of 22 vs 11% for those with between 80 and 100 mm Hg, and 8% for those with > 100 mm Hg (p < 0.001). However, in a multivariate analysis the systolic BP before infusion rather than the lowest systolic BP during infusion was independently associated with death. It is concluded that although patients with low systolic BP during streptokinase infusion have a high mortality, the level of systolic BP before infusion is more strongly associated with the outcome. Simultaneous use of intravenous beta blockade does not increase the occurrence of hypotension during streptokinase infusion.

Adult↗
PubMed1993

Chemical monitoring of intensive care patients using intravenous microdialysis.

The objective of the study was to evaluate intravenous microdialysis for monitoring of plasma lactate, pyruvate, glucose, creatinine, urea, adenosine, inosine and hypoxanthine in intensive care patients. Microdialysis probes (O.D. 0.9 mm; membrane length 20 mm) were inserted into major veins and perfused with Ringer's solution. Dialysis samples were collected from 4 patients with septic shock in 60 min fractions during 24 h. At the end of every hour a venous blood plasma sample was drawn from the corresponding contralateral vein for comparison. Microdialysate values of all metabolites closely followed the changes in the corresponding blood samples. The in vivo recovery of the probe type used was close to 100% for lactate, creatinine, and urea, and about 90% for glucose. It is concluded that intravenous microdialysis sampling is a suitable method for continuous bedside monitoring of important metabolites in intensive care patients.

Aged↗
PubMed1993

Impact of early thrombolysis on chest pain score reflecting myocardial ischemia in relation to various markers of ischemic damage. TEAHAT Study Group.

We randomized 352 patients with pain suggestive of acute myocardial infarction who were seen less than 3 h after onset of symptoms to either tissue plasminogen activator or placebo. The impact of treatment on chest pain score was assessed during the first 24 h and related to limitation of final myocardial damage as assessed by various indirect markers. The most marked effect of tissue plasminogen activator was observed in the chest pain score being reduced by 43% in the tissue plasminogen activator group as compared with placebo. Limitation of infarct size with tissue plasminogen activator reached the following percentage values when various methods were used: maximum serum lactate dehydrogenase I activity, 32%; vectorcardiography (QRS vector difference), 20%; electrocardiography (Palmeri score), 20%; ejection fraction, 9%. We conclude that early thrombolysis in acute myocardial infarction reduces the severity of chest pain by nearly 50%. The effect on chest pain is much more marked as compared with the effect on various markers of the final ischemic damage.

Aged↗
PubMed1993

Delay time between onset of myocardial infarction and start of thrombolysis in relation to prognosis.

In 292 patients with suspected acute myocardial infarction given thrombolytic agents, we describe the delay time between the onset of pain and the start of thrombolysis and relate the observations to the prognosis. In 3%, treatment was started 1 h or less and in 22% 2 h or less after onset of symptoms. The median delay time between onset of symptoms and arrival in hospital was 1 h 38 min, and the median delay time between the arrival in hospital and start of thrombolysis was 1 h 25 min. A very strong association between delay time to thrombolysis and mortality during 2 weeks and 1 year of follow-up was observed.

Aged↗
PubMed1993

Gunshot fatalities in Stockholm, Sweden with special reference to the use of illegal weapons.

During the years 1980-1992 the Swedish legislation regarding possession and use of firearms has remained fairly unchanged. Simultaneously the reported incidence of both stolen firearms and confiscation of illegally possessed handguns has increased significantly. In order to determine the impact of this trend on gunshot mortality, all victims of firearm fatalities subjected to medicolegal autopsy in the Stockholm area 1980-81 and 1990-91 were studied. The overall two-year rate increased from 50 to 65, homicides and suicides contributing seven new cases each; accidents and "not determined" comprising only 0 to 2 cases in each period. Suicides were four times as common as homicides in the former period; ca. three times as common in the latter. Thus, a 70% increase in homicidal shooting has occurred (from 10 to 17), and the fatal use of illegal firearms increased from 50% to 93%. As expected, there was a definite male dominance (96%) among perpetrators as well as among victims (85%). Concerning suicides, the rate in the latter period was 18% above that in the former; illegal guns were used in 30% in 1990-91 as compared to 20% 1980-81. The pattern of wounding in suicides was similar to that reported in earlier studies; confirming that entrance wounds in the back, extremities and lower abdomen are indicative of homicide. Thus, common sense knowledge of firearm fatalities are confirmed: More widespread access to illegal weapons conveys a higher rate of gunshot fatalities. The perpetrator is likely to be male. Suicidal shots are usually aimed at the head (mouth, temple, forehead) or precordium. Most gunshot suicides are committed by means of legally possessed firearms.

Adolescent↗
PubMed1992

Neuro-effector characteristics of sweat glands in the human hand activated by irregular stimuli.

Intraneural electrical stimulation of cutaneous fascicles in the median nerve was performed in 24 normal subjects and the effects on sweating within the innervation zone were monitored as changes of skin resistance and water vapour partial pressure (wvpp). The aims were: (1) to investigate the response variability between repeated stimulation sequences in the same skin site and between different sites and (2) to compare quantitative effects of regular and irregular stimulation on skin resistance and wvpp. Regional axillary anaesthesia of the brachial plexus eliminated spontaneous and reflex sympathetic activity. With repeated irregular stimulation sequences skin resistance responses from the same skin site varied only slightly between trials. Differences between response curves from two skin sites in the same subject or from different subjects were also small but significantly greater (P < 0.01) than differences between responses to repeated stimulation in the same site. Irregular stimulation with average frequencies of 0.49 Hz and 3.51 Hz gave greater resistance responses than if the same number of stimuli were delivered regularly (P < 0.01). The difference was most pronounced at 0.49 Hz. At an average frequency of 0.49 Hz the stimulation usually evoked no changes of wvpp whereas an average frequency of 3.51 Hz caused an increase of wvpp which was greater with irregular than with regular stimulation in all subjects. We conclude that: (1) sweat responses to sudomotor nerve traffic vary slightly due to local factors in the skin or the terminal nerve endings and (2) irregular sudomotor nerve traffic evokes more sweat than if the same impulses occur regularly.

Adult↗
PubMed1992

Non-linearity of skin resistance response to intraneural electrical stimulation of sudomotor nerves.

Intraneural electrical stimuli (0.3 mA, 0.2 ms) were delivered via a tungsten microelectrode inserted into a cutaneous fascicle in the median nerve at the wrist in 16 normal subjects, and the effects on the sweat glands within the innervation zone were recorded as changes of skin resistance. In order to examine the relationship between the skin resistance level and the amplitude of transient resistance responses, trains of high frequency stimulation were used to reduce the skin resistance level and then transient resistance responses were evoked by single stimuli at 0.1 Hz. Regional anaesthesia of the brachial plexus in the axilla eliminated spontaneous sympathetic activity and reflex effects. At high skin resistance levels response amplitudes to single stimuli were low but they increased successively to a maximum at intermediate levels and then decreased again at low resistance levels. Repeated stimulation sequences evoked qualitatively similar response curves but quantitatively both response amplitudes and skin resistance levels were slightly reduced upon repetition. We suggest that the changes of response amplitudes are due to variable resistivity of the corneal layer. The shifts of the response curves with repetition of stimulation may result from increased hydration of the corneum. It is concluded that the variability of response amplitudes to constant stimuli makes the amplitude of a skin resistance response unsuitable as an indicator of the strength of sympathetic sudomotor nerve traffic.

Adult↗
PubMed1992

The role of early surgery following myocardial infarction. European Coronary Surgery Bypass Group.

This co-operative study was a prospective randomised study to evaluate the role of coronary bypass surgery following acute myocardial infarction. The criterion for entry was an early positive exercise tolerance test. All patients who satisfied the clinical criteria of acute myocardial infarction but who were excluded had information on survival obtained after two years. A total of 4658 patients were assessed, with 3334 (71%) having a modified exercise test. This test was positive in 728 patients, of whom 598 then underwent coronary angiography. Three hundred and forty-eight patients were randomised (surgery 168, continuing medical treatment 180). At two years the survival in the medical group was 96% and in the surgical group was 93%. At five years the corresponding figures were 88% and 91%. Sub group analyses in terms of age, ejection fraction and extent of vessel disease failed to show any significant differences between those randomised to medicine or surgery. A positive exercise test early after infarction does help to delineate those more likely to require intervention, but a negative exercise test is not an indication for complacency.

Cardiac Surgical Procedures↗