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J Karlsson

Publications and source records attributed to J Karlsson.

At least 199 records · Page 11Linked to original sources
PubMed1990

A comparison of methodologies in detection of the anaerobic threshold.

Peak cardiopulmonary exercise performance is readily evaluated. The most appropriate methodology for assessment of submaximal exercise performance, however, is a subject of controversy. Therefore, we assessed the difference between conventional methodologies using standard criteria to estimate the onset of anaerobiosis and compared them with known gas exchange and blood lactate [( La]) concentrations. Oxygen uptake (VO2) was determined at both the gas exchange anaerobic threshold (ATge) and the lactate threshold (LaT) using the following three types of commonly used methodologies in a blinded fashion: 1) conventional techniques based on manual inspection of plots of gas exchange indexes and [La] versus time, 2) computerized linear regression analysis of two-segment model plots for VCO2 versus VO2 and log [La] versus log VO2, and 3) fixed values determining the VO2 at a respiratory exchange ratio (VCO2/VO2) of 1.00 and at an [La] of 2 mmol/l. Respiratory exchange data were collected on a breath-by-breath basis in 30 men with documented myocardial infarction. Simultaneously, arterial blood was sampled for [La] every 20 seconds during maximal exercise on an upright bicycle ergometer programmed for a continuous ramp protocol of 15 W/min. The mean (+/- SD) peak VO2 was 1,463 (+/- 312) ml/min. The mean (+/- SD) VO2 values for each method were as follows: (table; see text) These results indicate that a good positive correlation exists between the gas exchange and lactate data by all three approaches. The chosen fixed values yield the highest threshold detection for both ATge and LaT. Detection was lowest using regression analysis for LaT.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Walking efficiency before and after long-term muscle stretch in patients with spastic paraparesis.

Eight patients with stationary, spastic paraparesis were treated with long-term stretch of the hip adductor muscles to improve walking ability. Gait pattern, walking speed and perceived exertion of walking were assessed. Walking efficiency was assessed before and after treatment by measuring oxygen consumption and blood lactate level. After treatment walking pattern was improved. Perceived exertion decreased but walking speed was unchanged. Oxygen cost directly after treatment was lower in six patients, unchanged in one and higher in one. In the patient with unchanged oxygen cost the blood lactate level decreased, probably due to decreased recruitment of fast, type II muscle fibres. Blood lactate was unchanged in the other patients. When assessing walking ability, measurement of energy cost was found to be a valuable supplement to clinical judgement, but in spastic patients both oxygen cost and blood lactate must be considered.

Aged↗
PubMed1988

Onset of blood lactate accumulation exercise capacity, skeletal muscle fibers and metabolism before and after coronary artery bypass grafting.

Male patients with effort angina were studied before (n = 7), 1 week, and 1 and 6 months (n = 6) after coronary artery bypass grafting (CABG) with 2 to 7 grafts. The test battery included graded exercise, which was performed until unbearable leg exertion or chest pain, or both, was present. Onsets of blood lactate accumulation, anginal pain, leg exertion and dyspnea were interpolated for either the lactate concentration 2 mmol X 1-1 or the ratings 2 on the Borg subjective intensity scale. Onsets of blood lactate accumulation and symptom-limited exercise capacity before surgery amounted to 58 and 100 W, respectively. The corresponding figures 6 months later were the same for onset of blood lactate accumulation, whereas symptom-limited exercise capacity had increased by 58%. Blood lactate was the same at rest and mild exercise (congruent to onset of blood lactate accumulation) but more than doubled at symptom-limited exercise capacity (peak blood lactate concentration). Muscle fiber typing showed a low figure for the slow twitch fiber proportion (35%), which was unchanged after 6 months. Fast twitch subtype C was elevated before (7%) but disappeared after surgery, and fast twitch subtype A percent increased correspondingly. The major muscle biochemical changes were in the glycogenolytic pathway and the lactate dehydrogenase enzyme system, which appeared to increase in a quantitative manner, but with an unchanged relative lactate dehydrogenase isozyme pattern. The increased symptom-limited exercise capacity was related to the increased glycogenolytic activity and peak blood lactate (i.e., increased "anaerobic power"). Whether the causative explanation was the relief from chest pain, i.e., a psychophysiologic feature or the biochemical changes that took place in the muscle could only be speculated on.

Angina Pectoris↗
PubMed1988

Coenzyme Q10 and key enzyme activities in papillary muscle related to left ventricle function in mitral valve disease.

Coenzyme Q10 (CoQ10) was studied in papillary muscle from 18 patients (52-67 years, 2 females) subjected to open heart surgery due to mitral valve disease. In addition the enzyme activities of lactate dehydrogenase (LD) with its five isozymes, citrate synthase (CS) and mitochondrial CK (CK-MIT) were determined. Myocardial function was assessed by means of left ventricle (LV) angiography. CoQ10 averaged 0.39 (range 0.26-0.59) micrograms x mg-1 dw. On an individual basis CoQ10 was related to CS activity although not as closely as CK-MIT (r = 0.45, p less than 0.05 versus r = 0.86, p less than 0.001). The ratio (CoQ10) x (CS activity)-1 was calculated to represent mitochondrial quality. The level of LD3 fraction increase was used to mark for the degree of metabolic stress in the heart. LD3 fraction was negatively related to the quality index (r = -0.71, p less than 0.001). Thus, those with a low CoQ10 per unit of CS activity had also a high LD3 isozyme fraction. In a subset of 12 patients with isolated mitral regurgitation due to myxomatous valve degeneration, CoQ10 and the ratio CoQ10 over CS decreased with the degree of LV function impairment (r = -0.58, p less than 0.05 and r = -0.68, p less than 0.05, respectively). The quality index takes into account not only enzyme activity but also the potential for control of free oxygen radicals.

Aged↗
PubMed1988

Median nerve entrapment in bone after supracondylar fracture of the humerus. Case report.

A case is reported, where the median nerve was entrapped in a supracondylar humerus fracture, not preventing closed reduction. As serious impairment of the median nerve function did not improve within ten weeks, the nerve was explored and dissected out of the humerus using microsurgical technique, leading to complete recovery of the neural function. The purpose of this report is to draw attention to the fact, that the median nerve can be enclosed in supracondylar fractures reducable to good position and further, that delicate dissection of the nerve out of the bone does not necessitate sacrifice of its continuity.

Child↗
PubMed1988

The effects of omeprazole and cimetidine on duodenal ulcer healing and the relief of symptoms.

In a Swedish double-blind multicentre study, omeprazole (30 mg o.m.) was compared with the H2-receptor antagonist cimetidine (400 mg b.d.) in 152 patients. Clinical assessments and laboratory investigations were carried out at 2 and 4 weeks, and again at 6 weeks in unhealed patients. Endoscopy was performed at 2 weeks, and again at 4 and 6 weeks in unhealed patients. The patients in the two groups were well-matched prior to treatment. Omeprazole was superior to cimetidine in ulcer-healing rate after 2, 4 and 6 weeks. After 2 weeks of treatment, 66% of the omeprazole- and 45% of the cimetidine-treated patients were healed (P = 0.02), after 4 weeks 97 and 84% (P = 0.01), and after 6 weeks 100 and 92% (P = 0.02), respectively. There was a more pronounced improvement in the patients' symptoms in the omeprazole group after 2 weeks (P = 0.05). Both drugs were well-tolerated, but there was a high prevalence of patients with adverse events in the cimetidine group (51%, compared to 30% of the omeprazole group; P = 0.02). A total of 125 patients were followed for 6 months after healing. The patients were investigated by endoscopy after 6 months, or whenever symptoms occurred. There was no significant difference in the rate of relapse within 6 months between the two treatment groups: 54% relapsed in the omeprazole group and 52% in the cimetidine group. In conclusion, 30 mg of omeprazole, given once daily, is superior to 400 mg of cimetidine twice daily in duodenal ulcer healing; but ulcer relapse in the two groups appears to be equivalent.

Adolescent↗
PubMed1988

Effects of chronic sympathectomy on muscle fibre composition ISO-myosin patterns, protein synthesis and calcium content in canine gracilis muscle.

We have previously reported functional and histological studies in five beagle dogs with unilateral lumbar sympathectomy. Three months later, fatiguability in the gracilis muscles was increased on the denervated sides, and this was associated with an increase in the relative distribution of FT fibres. Biochemical studies now show that these changes were associated with an increase in cytosolic protein without change in DNA content; this is consistent with an increase in cell size. There was a reduction in the proportion of slow myosin light chain isoforms from 50 +/- 7 to 34 +/- 6%. Noradrenaline levels were increased on the denervated sides but this may reflect greater vascularity. Calcium content did not correlate with fibre type but there was a positive relation with both noradrenaline content (r = 0.73; P less than 0.05) and DNA content (r = 0.84; P less than 0.05). It is concluded that sympathectomy induces several biochemical changes in skeletal muscle which constitute a change and increase in fast myosin light chain synthesis and a corresponding fibre type transformation.

Animals↗
PubMed1988

Coenzyme Q10 content in different parts of the normal human heart.

Coenzyme Q10 (CoQ10) and citrate synthase (CS) activities were analysed in the myocardium of brain-dead organ donors (14-40 years). Different parts of the heart were studied: right and left auricular appendage, right and left atrium, right ventricle (septum and free wall) and left ventricle (septum, free wall, and papillary muscle). Freeze-dried, dissected myocardial samples were analysed for CoQ10 content by HPLC and CS activity by fluorometric technique. CoQ10 content in the normal human myocardium was lowest in auricular appendages and atria (0.25 +/- 0.06 mg X g-1 dry muscle), intermediate in right ventricle (0.37 +/- 0.05 mg X g-1 dm) and highest in left ventricle (0.42 +/- 0.07 mg X g-1 dm). CS activity showed the same relationship between these locations as CoQ10. The results suggest that there exist differences in CoQ10 content between different parts of the normal human myocardium. These differences were closely related to the differences in CS activity between corresponding parts. The differences between different parts of the heart may be related to divergent work demand, and the constant relationship between CS and CoQ10 may be related to their coupling to the mitochondrial oxidative metabolism.

Adult↗
PubMed1988

Lateral instability of the ankle treated by the Evans procedure. A long-term clinical and radiological follow-up.

We have reviewed 42 of 52 consecutive patients at an average of 14 years after a tenodesis based on Evans' operation performed for chronic lateral instability of the ankle. Only 21 patients (50%) had satisfactory long-term functional results, and 12 patients with satisfactory early results had deteriorated after three to six years. Stress radiographs were used to measure anterior talar translation and talar tilt, and a good correlation was found between function and mechanical stability. Talar tilt had been controlled more successfully than anterior translation. Marginal osteophytes were found in most ankles, and were larger and more numerous in those with the greatest instability.

Adolescent↗
PubMed1988

Patellar instability with recurrent dislocation due to patellofemoral dysplasia. Results after surgical treatment.

Twenty-one patients (25 knees) with recurrent dislocation of the patella due to patellofemoral dysplasia were treated with a combined distal and proximal realignment of the extensor mechanism of the knee. In addition to traditional medial transfer of the tibial tuberosity, lateral release, and medial joint capsule duplication, vastus medialis transposition and deepening of the intercondylar sulcus on the proximal joint surface of the femur were done. A follow-up ranging from 1-14 years (mean 6 years) found the results excellent or good in 22 knees, fair or poor in three. One redislocation occurred after trauma. There were two minor complications which had no effect on the end result. The use of computerized tomography over the patellofemoral joint to assess patellar subluxation and patellofemoral dysplasia is an important part of the diagnostic preoperative evaluation.

Adult↗
PubMed1988

Reconstruction of the lateral ligaments of the ankle for chronic lateral instability.

One hundred and seventy-six patients (180 ankles) who had chronic lateral instability of the ankle were treated with transection and imbrication of the anterior talofibular ligament. Sixty-eight of the ankles had reconstruction of the calcaneofibular ligament as well. Of the 176 patients, 148 (152 ankles) were available for follow-up, which ranged from two to twelve years (mean, six years). An excellent or good result was achieved in 132 ankles, all of which had improved mechanical stability as measured radiographically. Sixteen of the twenty ankles that had an unsatisfactory result were in patients who had generalized hypermobility of the joints or long-standing local ligamentous insufficiency, or both, or who had had a previous operation. Reconstruction of both ligaments gave a better functional result than when only the anterior talofibular ligament was reconstructed.

Adolescent↗
PubMed1987

Prolonged exercise at a constant load on a bicycle ergometer: ratings of perceived exertion and leg aches and pain as well as measurements of blood lactate accumulation and heart rate.

To study changes over time during prolonged exercise on a bicycle ergometer at a constant load, 22 healthy males rated perceived exertion as well as aches and pain in the legs, and measurements were taken on blood lactate accumulation and heart rate (HR). The prolonged exercise was carried out at WOBLA (the power level eliciting a blood lactate concentration of 4 mmol X l-1). All four measured variables, ratings of perceived exertion, ratings of aches and pain in the legs, blood lactate accumulation, and HR, grew systematically according to negatively accelerating functions. HR showed more of a steady state, whereas all the other three variables grew continuously over time. Three subgroups were identified related to the blood lactate response after 15 min at WOBLA: elevated (greater than 5 mmol X l-1), intermediate (3.5-4.9 mmol X l-1), and low (less than 3.4 mmol X l-1). It was suggested that a major contribution to the discrepancies in blood lactate between the subgroups after 15 min was partly due to insufficient warming up, which was 5 min at 20 W as compared with the final power level (WOBLA), which differed between 140 and 260 W. After 15 min both rated perceived exertion and rated aches and pain in the legs were related to the corresponding blood lactates. It was suggested that rated perceived exertion and rated aches and pain in the legs partly reflected the degree of "anaerobic" metabolism measured as blood lactate.

Adult↗
PubMed1987

Myocardial demands of atrial-triggered versus fixed-rate ventricular pacing in patients with complete heart block.

Hemodynamics, myocardial oxygen consumption, and lactate concentration were determined by cardiac catheterization at rest and during exercise in eight patients treated with AV universal pacemakers (DDD) for high degree AV block. The pulse generator was alternately programmed in ventricular inhibited (VVI) or atrial synchronous (VAT) mode. During VVI pacing, the cardiac output rose between rest and exercise (4.3-7.6 L/min) due to increased stroke volume. VAT pacing gave significantly greater increase (4.5-8.8 L/min) which, as the stroke volume was unchanged, resulted from accelerated heart rate. The myocardial oxygen consumption and the coronary blood flow did not differ between VVI and VAT mode at rest or during exercise, nor did the modes make a difference in arterial systolic and pulmonary wedge pressures. These observations suggested that VAT pacing offers higher cardiac output than VVI pacing, but with similar demands on myocardial oxygen consumption.

Aged↗
PubMed1987

Irreducible fracture of the wrist in a child. Entrapment of the extensor tendons.

A previously undescribed fracture-separation of the distal radial and ulnar physis is presented. A Salter-Harris Type II phys-metaphyseal fracture of both radius and ulna, with volar displacement, was found irreducible by closed means. At operation the extensor tendons were found entrapped between the metaphysis and epiphysis of both radius and ulna, which prevented reduction. Reduction was possible only after this entrapment was released.

Adolescent↗
PubMed1986

Acromioclavicular dislocations treated by coracoacromial ligament transfer.

Forty-seven patients with acute Allman type-III acromioclavicular dislocations were treated with open reduction and coracoacromial ligament transfer. At follow-up 1.6-10 years (mean 6) post-operatively 44 patients (94%) had excellent or good functional results. Two of the three patients with unsatisfactory results had degenerative joint changes. No late dislocation was found but there were three subluxations (3-5 mm). Two of the three patients with subluxation in the acromioclavicular joint at follow-up had unsatisfactory results. Complications were infrequent and cosmetic results satisfactory.

Acromioclavicular Joint↗
PubMed1986

Entrapment of the median nerve and brachial artery after supracondylar fractures of the humerus in children.

Four patients, all children, with dislocation and entrapment of the median nerve and brachial artery following supracondylar fractures of the humerus are described. Circulation and neural function were restored in all cases by operation. Exploration of the neurovascular structures is recommended if dislocation and entrapment of the median nerve and brachial artery are suspected.

Brachial Artery↗