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Biomedical subjects

T Karlsson

Publications and source records attributed to T Karlsson.

At least 127 records · Page 7Linked to original sources
PubMed1996

Mortality and morbidity in diabetic and nondiabetic patients during a 2-year period after coronary artery bypass grafting.

OBJECTIVE: To describe mortality and morbidity during a 2-year period after coronary artery bypass grafting (CABG) among diabetic and nondiabetic patients. RESEARCH DESIGN AND METHODS: All the patients in western Sweden in whom CABG was undertaken between June 1988 and June 1991 and in whom concomitant procedures were not performed were registered prospectively. The study was a prospective follow-up. RESULTS: Diabetic patients (n = 268) differed from nondiabetic patients (n = 1,859) in that more women were included, and the patients more frequently had a previous history of myocardial infarction (MI), hypertension, congestive heart failure, intermittent claudication, and obesity. Diabetic patients more frequently required reoperation and had a higher incidence of peri- and postoperative neurological complications. Mortality during the 30 days after CABG was 6.7% in diabetic patients versus 3.0% in nondiabetic patients (P < 0.01). Mortality between day 30 and 2 years was 7.8 and 3.6%, respectively (P < 0.01). During 2 years of follow-up, a history of diabetes appeared to be a significant independent predictor of death. Whereas the development of MI after discharge from the hospital did not significantly differ between the two groups; 6.3% of diabetic patients developed stroke versus 2.5% in nondiabetic patients (P < 0.001). CONCLUSIONS: Diabetic patients have a mortality rate during the 2-year period after CABG that is about twice that of nondiabetic patients during both the early and late phase after the operation.

Age Factors↗
PubMed1996

Replacement of the ascending aorta with composite valve grafts: long term results.

BACKGROUND AND AIMS OF THE STUDY: Long term survival after replacement of the aortic root is improving. The most common cause of late death is progression of disease in the remaining aorta (dissection or atherosclerosis). The purpose of this study was to review our clinical experience with composite graft replacement of the aortic root with special reference to long term results. MATERIALS AND METHODS: One hundred twenty-six patients (mean age: 53 years) with different pathologies of the ascending aorta underwent aortic root replacement with a composite-graft prosthesis over a 12-year period. Twenty-three patients had previously undergone cardiovascular surgery. The surgical technique included resection of the ascending aorta with the aortic valve and end-to-side anastomosis between full-thickness buttons of the aortic wall with the coronary ostia and the graft. One or more associated cardiovascular procedures were performed in 24 cases. Long term follow up to July 1995 is complete. Uni- and multivariate analysis were performed to identify risk-factors for early and late mortality and reoperation. RESULTS: Twenty-three patients died during the first 30 days (18%). Sixteen of them had aortic dissection. The most common cause of early death was heart failure. Twenty-three patients died during the follow up time with heart failure, again, being the most common cause of death. Thirteen late reoperations on the composite-graft or the remaining aorta were performed in 12 patients, six of whom had Marfan's syndrome. The 30-day mortality at reoperation was 30%. CONCLUSIONS: This surgical option offers good long term results with a five-year actuarial survival of 67% or 75% when the 30-day mortality is excluded. Careful follow up of patients with Marfan's syndrome and/or aortic dissection is mandatory to increase the long term survival.

Adolescent↗
PubMed1995

Mutation analysis of the chromosome 14q24.3 dihydrolipoyl succinyltransferase (DLST) gene in patients with early-onset Alzheimer disease.

Linkage analysis studies have indicated that the chromosome band 14q24.3 harbours a major gene for familial early-onset Alzheimer's disease (AD). Recently we localized the chromosome 14 AD gene (AD3) in the 6.4 cM interval between the markers D14S289 and D14S61. We mapped the gene encoding dihydrolipoyl succinyltransferase (DLST), the E2k component of human alpha-ketoglutarate dehydrogenase complex (KGDHC), in the AD3 candidate region using yeast artificial chromosomes (YACs). The DLST gene is a candidate for the AD3 gene since deficiencies in KGDHC activity have been observed in brain tissue and fibroblasts of AD patients. The 15 exons and the promoter region of the DLST gene were analysed for mutations in chromosome 14 linked AD cases and in two series of unrelated early-onset AD cases (onset age < 55 years). Sequence variations in intronic sequences (introns 3, 5 and 10) or silent mutations in exonic sequences (exons 8 and 14) were identified. However, no AD related mutations were observed, suggesting that the DLST gene is not the chromosome 14 AD3 gene.

Acyltransferases↗
PubMed1995

Arteriovenous anastomoses and the thermoregulatory shift between cutaneous vasoconstrictor and vasodilator reflexes.

The reflex changes in skin blood flow which occur in response to various non-thermal stimuli (e.g., deep inspiratory gasps, arousing or painful stimuli, emotional stress) are profoundly influenced by the thermoregulatory state. The aim of the present study was to evaluate the involvement of arteriovenous anastomoses in the thermoregulatory modulation of skin vasomotor reflexes elicited by painful intraneural electrical stimulation and emotional stress (forced arithmetics), respectively. Vasomotor responses were recorded with laser Doppler flowmeters (LDF) placed on glabrous skin containing arteriovenous anastomoses (3rd finger and thenar eminence) and hairy skin which lack them (dorsal side of the first metacarpal bone). In some experiments, a laser Doppler flowmeter emitting laser light of two different wavelengths (infrared and green light) into the same skin site was used to record skin perfusion at different depths of glabrous skin on the thenar eminence. 40 subjects were investigated, both in the cold state (finger skin temperatures below 25 degrees C) and after subsequent warming (finger skin temperatures above 30 degrees C). Thermoregulatory modulation of electrical stimulation- or stress-induced vasomotor reflexes occurred both in glabrous and hairy skin, but hairy skin differed from glabrous skin by showing no significant vasoconstrictions. Relative perfusion changes were most marked in laser Doppler flowmeter recordings using the deeper penetrating infrared light. The results suggest that arteriovenous anastomoses are major contributors to the vasoconstrictor component of vasomotor reflexes in glabrous skin of warm subjects. The reflex increase in perfusion, on the other hand, which occurs in both glabrous and hairy skin of cold subjects may be mediated by resistance vessels.

Adult↗
PubMed1995

Molecular interactions of the Src homology 2 domain protein Shb with phosphotyrosine residues, tyrosine kinase receptors and Src homology 3 domain proteins.

The molecular interactions of the Src homology 2 (SH2) domain and the N-terminal proline-rich sequence motifs (pro-1 to pro-5) of the SH2 protein Shb with other components were presently characterised. Using a degenerate phosphopeptide library the preferred binding site for the Shb SH2 domain was determined to pTyr-Thr/Val/Ile-X-Leu at positions +1 to +3 relative the phosphotyrosine residue. Experiments with competing peptides and platelet-derived growth factor (PDGF) beta-receptor mutants with Y to F substitutions in autophosphorylation sites revealed multiple binding sites for the Shb SH2 domain in the receptor. The Shb SH2 domain also binds to in vitro phosphorylated fibroblast growth factor receptor-1 (FGFR-1) mainly through position Y776. The receptor experiments suggest that other residues besides the +1 to +3 positions may also be of significance for Shb binding. The pro-4/pro-5 motif of Shb binds in vitro particularly well to the Src, p85 alpha PI3-kinase and Eps8 SH3 domains expressed as GST fusion proteins. However, the GST-SH3 domain fusion proteins tested bind in vitro to peptides corresponding to the pro-1 to pro-5 motifs of Shb with low affinity and selectivity, suggesting that sequences outside the core proline motif may also be important for Shb-SH3 domain interactions. In vivo association between Shb-SH3 domain proteins v-Src and Eps8 was detected by coimmunoprecipitation. PDGF treatment did not affect the association between Eps8 and Shb. The data suggest that Shb is an adaptor protein linking SH3 domain proteins to tyrosine kinases or other tyrosine phosphorylated proteins.

Amino Acid Sequence↗
PubMed1995

The predictive value of cerebrospinal fluid dynamic tests in patients with th idiopathic adult hydrocephalus syndrome.

OBJECTIVE: To evaluate the predictive value of the cerebrospinal fluid (CSF) tap test and CSF outflow conductance in the selection of patients with the idiopathic adult hydrocephalus syndrome, defined exclusively on a clinical basis, for shunt surgery. DESIGN: A prospective, consecutive case series. All patients were assessed before surgery and at 3 months after shunt placement. Preoperatively, CSF pressure, conductance, and CSF formation rate were assessed by a constant-pressure infusion method. Improvement in gait and cognitive functions after removal of CSF was noted (ie, with the CSF tap test). Postoperatively, the infusion method was used to evaluate shunt function. SETTING: Tertiary, academic referral center. PATIENTS: Thirty-five patients with idiopathic adult hydrocephalus (normal-pressure hydrocephalus) syndrome based on conservative clinical criteria. No predictive tests were used for inclusion. All patients had a typical gait disturbance and a communicating hydrocephalus. Twenty-eight patients also had dementia or incontinence, or both. INTERVENTION: The CSF diversion (Cordis, [Orbis-Sigma]) valve, six patients; Hakim's standard system (Cordis Hakim standard system), 29 patients. OUTCOMES OF SURGERY: Serial videotaping of gait, a comprehensive neuropsychologic battery, and the Bartel index of activities of daily life. RESULTS: Gait was improved in 25 (72%) of the 35 patients, whereas the Bartel index remained unchanged. The conditions of five of seven patients with gait disturbance as the sole symptom improved. The spatial function (37% improved) and the findings from the Fuld object memory tests (29% improved) were significantly improved. Shunt dysfunction could not explain the lack of effect of an operation in the remaining patients. It should be noted that these results obtained at 3 months postoperatively may not be applicable in a long-term perspective. The CSF outflow conductance or CSF tap test were not able to identify those patients who would or would not benefit from a CSF diversion procedure. However patients had a lower conductance and a higher CSF pressure than did control subjects. CONCLUSIONS: Considerable improvement in gait was seen, but cognitive function was little affected. The CSF tap test or conductance does not provide additional information that is necessary to distinguish between patients whose conditions will or will not respond to shunting, when selection for surgery is based on conservative clinical criteria.

Activities of Daily Living↗
PubMed1995

Long-term memory deficits in patients with malignant gliomas.

Knowledge about the neuropsychological performance of adult patients with brain tumors, and especially with malignant gliomas, is limited. In this study 30 patients were consecutively included at time of diagnosis. Five months after completion of radiotherapy eleven of the patients showed no signs of focal neurology or tumor recurrence. These eleven patients, and their partners, were interviewed independently. Using each partner as control the patients were assessed neuropsychologically with special emphasis on memory abilities. The selective reminding technique was used with nouns of different visual imagery. A consistent pattern was found: there was no clear impairment in global intellectual abilities, but there was a pronounced deficit in long-term memory. However, the patients had a preserved capacity to use visual imagery to boost performance. It is important that medical staff acknowledge or confirm this problem. The sparing of imaginal coding makes it possible for the staff to assist with advice facilitating memory. Memory is a vital cognitive ability and the selective reminding technique was a sensitive method capable of detecting subtle impairments. The technique is recommended in future examinations of conditions and evaluations of treatments affecting the CNS.

Adult↗
PubMed1995

Mortality during the two years after coronary artery bypass grafting in relation to perioperative factors and urgency of operation.

The purpose of this study was to describe mortality during the 2-year-period after coronary artery bypass surgery (CABG) in relation to perioperative risk factors and urgency of operation. All the patients in western Sweden were included in whom CABG was performed between June 1988 and June 1991, without concomitant procedures or re-operations. The study was prospective in design. In all, 2000 patients were operated upon and 186 (9.3%) of the operations were acute. There was a significant relationship between the urgency of the operation and mortality. Early mortality was 2.4% in elective operations and 5.4-62.5% in urgent to emergency operations. The 30-day to 2-year mortality was 4.2%. The perioperative risk indicators independently associated with early mortality were neurologic complications, serum-aspartate aminotransferase (S-ASAT) more than 2.0 microkat/l, urgency of operation, the use of circulatory assist devices, re-operation and ventilator time more than 24 h. The risk indicators for mortality after 30 days were pneumothorax, longer intensive care unit (ICU) time, the use of inotropic drugs and neurologic complications. In conclusion, the multivariate analysis reveals the urgency of the operation as a predictor of early mortality after CABG, but no significant association with mortality was found after 30 days. When excluding death within 30 days, three additional independent predictors of mortality were identified.

Adult↗
PubMed1995

Preoperative risk indicators of death at an early and late stage after coronary artery bypass grafting.

The aim of the study was to describe mortality during a period of two years after coronary artery bypass surgery (CABG) in relation to preoperative risk factors. Included were all the patients in western Sweden in whom CABG was performed between June 1988 and June 1991, without concomitant procedures or re-operations. The study was prospective in design. In all, 2000 patients with a median age of 64 years were operated upon. Early (within 30 days) mortality was 3.0% and late (30-day-2-year) mortality was 4.2%. Total two-year mortality was 7.1%. For patients undergoing coronary artery bypass grafting, the factors found to be independently predictive of early mortality were female sex, renal dysfunction (creatine clearance < 60ml/min), left main stenosis, number of diseased vessels, previous myocardial infarction, and functional class. We found that a history of congestive heart failure, a history of cerebrovascular disease, diabetes mellitus, renal dysfunction and intermittent claudication were independent risk factors for late mortality. In conclusion, with the exception of renal dysfunction, preoperative risk factors for death within 30 days after CABG differ from risk factors for death between 30 days and two years after CABG.

Adult↗
PubMed1995

Ambulance despatchers' estimation of intensity of pain and presence of associated symptoms in relation to outcome in patients who call for an ambulance because of acute chest pain.

BACKGROUND: A large number of patients who call for an ambulance because of acute chest pain have an acute ischaemic event, but some do not. AIM. To relate the ambulance despatcher's estimated severity of pain and presence of associated symptoms, in patients who call for an ambulance because of acute chest pain, to whether they develop acute myocardial infarction (AMI) and to the risk of early death. PATIENTS: All those with acute chest pain who contacted the despatch centre in Göteborg over a 2-month period. RESULTS: In all, 503 patients fulfilled the inclusion criteria. Patients judged as having severe chest pain (68%) developed AMI during the first 3 days in hospital on 26% of occasions as compared with 13% among patients judged as having only vague chest pain (P = 0.0004). The difference was less marked among the elderly and women. The presence of any of the following associated symptoms, dyspnoea, nausea, vertigo, cold sweat or syncope, tended to be associated with a higher infarction rate (24%) than if none of these symptoms was present (17%, P = 0.06). Mortality during the pre-hospital and the hospital phase was not associated with the estimated severity of pain or the presence of associated symptoms. CONCLUSIONS: The despatcher's estimation of the severity of pain and the presence of associated symptoms appears to be associated with the development of AMI but not with early mortality.

Adolescent↗
PubMed1995

Outcome for patients who call for an ambulance for chest pain in relation to the dispatcher's initial suspicion of acute myocardial infarction.

The very early handling of patients with suspected acute myocardial infarction (AMI) is of critical importance to the outcome. The aim of this study was to relate the dispatcher's initial suspicion of AMI, among patients who call for an ambulance due to chest pain, to the subsequent diagnosis and outcome. All patients who called for an ambulance in Gothenburg due to acute chest pain during a 2-month period were included in the study. In all, 503 patients fulfilled the inclusion criteria, and information on the dispatcher's initial suspicion of AMI was available in 484 patients. There was at least a strong suspicion of AMI in 36%, a moderate suspicion of AMI in 34% and only a vague or no suspicion in 30%. Among patients with at least a strong suspicion of AMI, 29% subsequently developed infarcation, compared with 18% among patients with a moderate suspicion of AMI and 15% among patients with only a vague or no suspicion (p < 0.001). However, the priority level was similar in patients with and without a life-threatening condition, and the mortality rate remained similar in patients with a strong suspicion and those without a strong suspicion of AMI. Thus, among patients who called for an ambulance due to acute chest pain there was a direct relationship between the dispatcher's suspicion of AMI and the subsequent diagnosis, but the mortality rate was similar in the different groups.

Adult↗
PubMed1995

Demonstration of specific high-affinity Fc epsilon-receptors on the human basophil-like leukemia cell line KU812 by flow cytometry.

The specificity of IgE binding to a human basophil-like cell line (KU812) was studied by flow cytometry. Four IgE myeloma proteins, representing both light-chain types, one chimeric IgE protein, and polyclonal serum IgE blocked the direct binding of FITC-labeled IgE(DES) myeloma protein to KU812 cells in a dose-dependent and nearly equimolar way. Although not as efficiently as human IgE (from five to eight times less on a molar basis), both rat and mouse IgE blocked IgE(DES)-FITC binding to KU812 cells. In sharp contrast, all four human IgG subclasses, both IgA subclasses, and IgM myeloma proteins, as well as monomeric and heat-aggregated polyclonal human IgG, were unable to block significantly IgE(DES)-FITC binding to KU812 cells (< 0.5% on a molar basis). The cytophilic epitope on IgE was heat-susceptible (56 degrees C, 2 h), lost after reduction alkylation, and resident in the papain-derived Fc epsilon-fragment, but not in the papain-derived Fab epsilon- and Fc'epsilon-fragments nor in the pepsin-derived F(ab')2 epsilon- and Fc"epsilon-fragments. Washing and displacement experiments indicated that a major part of IgE reacted with high affinity to KU812 cells. The results indicate that the binding of IgE to KU812 cells is highly specific and involves the classical high-affinity Fc epsilon RI-receptor. Although the density of receptors is low, this human cell line offers a unique model to study IgE/Fc epsilon RI interactions.

Animals↗
PubMed1995

Lactate metabolism and hypocarbic hyperventilation. An experimental study in piglets.

Hyperventilation has been reported to increase blood lactate levels. Uncertainty exists as to whether high lactate levels are caused by increased peripheral release or decreased hepatic uptake. Seven piglets were investigated during controlled normoventilation and 13 piglets during controlled hyperventilation. Blood was drawn from catheters in the femoral artery and vein and in the hepatic vein. Blood flow was measured in the femoral artery by an electromagnetic flow meter and in the splanchnic area by indocyanine green extraction. In addition, repeated muscle biopsies from the hind limb and back muscles were taken. The mean PaCo2 was 5.4 in the normoventilated and 3.5 kPa in the hyperventilated group. The average hind limb oxygen uptake was the same in both groups. The arterial blood lactate concentration was significantly higher (P = 0.03) in the hyperventilated group (2.6 mmol.l-1) as compared to the normoventilated group (1.5 mmol.l-1). However, the release of lactate from the hind limb, and the muscular content of lactate were the same in both groups. Similar and unchanged skeletal muscle contents of glucose-6-phosphate, fructose-1,6-diphosphate, alpha-glycerophosphate, pyruvate, citrate and ATP were recorded in both groups. The splanchnic region did not take up or release lactate at normal PaCO2, but released lactate after 120 minutes of hyperventilation. The results indicate that the increased concentration of lactate during hypocarbic hyperventilation was not caused by an increased peripheral release from the skeletal muscles of the pig but could be caused by an altered splanchnic turn-over of lactate.

Adenosine Triphosphate↗
PubMed1995

Central blood volume influences sympathetic sudomotor nerve traffic in warm humans.

The objective of this study was to test whether changes in central blood volume can induce reflex effects on sweating. Multi-unit skin sympathetic nerve activity (SSA) was recorded from the posterior cutaneous nerve of the forearm or radial nerve branches in 11 healthy volunteers. Skin electrical resistance and skin blood flow were recorded in the area innervated by the impaled nerve fascicle. Sudomotor nerve traffic and sweating was induced by whole body heating. Lower body negative pressure (LBNP) and tilting (30 degrees head up) was used for blood volume displacement from the chest to the lower body. Low levels of LBNP (5 and 10 mmHg) had no effect on blood pressure, heart rate or skin blood flow but induced a prompt inhibition of SSA and a reduced number of transient skin resistance changes (n = 9), both rapidly returning to control levels after cessation of LBNP. Quantitatively, the effect was similar at both levels of LBNP. Head up tilting also reduced SSA (n = 3, 19 tilt manoeuvres). A capacity for mental stress-induced SSA increase remained during LBNP. Spontaneous fluctuations in blood pressure did not affect SSA, arguing against arterial (high-pressure) baroreceptors modulating SSA. Consequently, the present results indicate that unloading of cardiopulmonary (low-pressure) volume receptors reduces sympathetic sudomotor nerve traffic and sweating in warm subjects. It is suggested that the reflex contributes to counteracting hypovolaemia.

Adrenergic Fibers↗
PubMed1995

Diagnostic accuracy of physicians for identifying patients with acute myocardial infarction without an electrocardiogram. Experiences from the TEAHAT Trial.

AIM: To determine the diagnostic accuracy of physicians for identifying patients with acute myocardial infarction (AMI) without an electrocardiogram (ECG). PATIENTS: All patients in Göteborg with suspected AMI below 75 years of age who called for an ambulance or came directly to one of the two city hospitals with a delay time of less than 2 h 45 min from the start of symptoms. METHODS: As part of the TEAHAT study (comparing rt-PA and placebo in AMI), we asked physicians to judge on a 1-5 scale (1 = no suspicion; 5 = convinced) how strong their suspicion of AMI was prior to interpreting the ECG. RESULTS: Among patients evaluated outside hospital with 4 or 5 on the scale, i.e. either a strong suspicion of AMI or the physician felt convinced about the diagnosis, 45% had ST elevation and 48% developed AMI during the first 3 days in hospital. The corresponding values for patients evaluated in hospital were 67 and 70%, respectively. CONCLUSION: We found that physicians could not accurately distinguish patients with AMI from those without based on clinical criteria without the help of an ECG.

Acute Disease↗
PubMed1995

Autonomic and thermal sensory symptoms and dysfunction after stroke.

BACKGROUND AND PURPOSE: Symptoms interpreted as unilateral disturbances of autonomic function, such as coldness, dryness, sweating, and trophic changes, are well known but incompletely understood clinical problems after stroke. The present study provides data related to the incidence and mechanisms behind such symptoms. METHODS: Temperature perception thresholds, skin temperatures, evaporation rates, and skin blood flow responses were measured bilaterally in 37 stroke patients aged 58 +/- 13 years (mean +/- SD) and in a control group of 15 patients aged 64 +/- 15 years with a single transient ischemic attack. RESULTS: Of the 37 stroke patients, 43% reported a sensation of coldness in the contralesional side of the body. Basal skin blood flow and temperature were relatively lower in the contralesional side. There was an excess of evaporation in the contralesional side after brain stem lesions and in the ipsilesional side after hemispheric lesions. Vasomotor reflex asymmetries occurred in 34% of the patients and were due to weak vasodilator or vasoconstrictor reflexes in the ipsilesional side. These abnormalities correlated significantly to sensations of unilateral coldness, hypalgesia, and thermohypesthesia in the contralesional side and anatomically to lesions in spinothalamo-cortical pathways. CONCLUSIONS: Focal central nervous system lesions due to stroke may result in symptoms and measurable evidence of unilateral disturbance of skin sympathetic function. Vasomotor asymmetries are probably due to lesions of vasomotor pathways descending uncrossed. Subjective coldness may be due to disturbed central processing.

Aged↗
PubMed1995

Influence of patient sex and clinical history on working capacity and myocardial ischemia after coronary artery bypass surgery.

BACKGROUND: Coronary artery bypass grafting (CABG) is generally accepted as effective in relieving patients from angina pectoris, and in improving survival in subgroups. However, subset evaluations of myocardial ischemia and exercise capacity after CABG are scarce. The aim of this study was to determine the outcome of CABG in terms of exercise capacity and stress ECG findings in subgroups of patients. METHODS: A stepwise bicycle exercise ECG (in most cases computerized) was performed on 362 patients within 1 year before and 2 years after CABG. RESULTS: Exercise capacity increased from a median value of 90 to 130 W (P < 0.0001), more marked (P < 0.0001) in men (100-140 W) than in women (75-90 W). Improvement was not significantly related to age. Occurrence of ST-segment depression at exercise decreased, 76% showing ST-segment depression of at least 1 mm before the operation and 35% (P < 0.0001) 2 years after. Exercise-induced signs of ischemia on ECG did not differ between men and women. Maximum heart rate increased from a median value of 109 to one of 133 beats/min (P < 0.0001), and maximum systolic blood pressure from 170 to 210 mmHg (P < 0.0001). Termination of exercise because of chest pain decreased from 48 to 6% (P < 0.0001). Most subsets of patients improved exercise capacity with a reduction of ST-segment depression irrespective of their previous history and manifestations of cardiovascular disease. CONCLUSIONS: CABG caused a marked increase in exercise capacity and reduced signs of myocardial ischemia. Although men increased their working capacity by a greater extent than women, reduction in signs of myocardial ischemia was similar in both sexes.

Aged↗