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Biomedical subjects

B Semb

Publications and source records attributed to B Semb.

16 recordsLinked to original sources
PubMed1997

Vitamins Q and E, extracorporal circulation and hemolysis.

Whole blood vitamin Q (ubiquinone), plasma vitamins Q and E (alpha-(alpha-)tocopherol) and free cholesterol (FC) were studied before (control or base-line value, sample I) and during open chest surgery and extracorporal circulation (samples II-IV) in 10 male IHD patients. Identity existed between control whole blood and plasma ubiquinone. During surgery an increased discrepancy with lower plasma vitamin Q levels were seen. Control plasma vitamins Q, E and FC averaged 0.88 +/- 0.16 (SE), 12.1 +/- 2.2 mg x l(-1) and 0.75 +/- 0.15 g x l(-1). Corresponding molar values were 1.02 +/- 0.17, 28.1 +/- 5.1 micromol x l(-1) and 1.94 +/- 0.74 mmol x l(-1). Vitamin Q and E decreased continuously and averaged 0.64 mg x l(-1) in sample IV (0.74 micromol x l(-1), p < 0.001) and 9.4 mg x l(-1) in sample III (21.8 micromol x l(-1), p < 0.001). Hemolysis in all sample IV vials, ruined all vitamin E determinations. When normalized for FC (NQ and NE), decreases were found to be 17 (IV) and 12% (III), respectively. Large interindividual variations existed. High control NQ and NE values allowed a larger antioxidant vitamin depletion. High NQ seemed also to be a prerequisite for NE depletion. In addition, signs indicated an active liver vitamin Q release for patients rich in control antioxidant values. It was suggested that the antioxidant vitamin depletion did not prevent from radical trauma to membrane structural lipids (especially omega-3 fatty acids or vitamin F1), less membrane fluidity, erythrocyte fragility and hemolysis.

Aged↗
PubMed1997

Heart muscle and plasma vitamin Q with heart transplantation.

OBJECTIVE: To study variations in heart muscle septum and plasma vitamin Q (Q, ubiquinone, n = 9) and plasma vitamin E (E, alpha-tocopherol, n = 4) in heart transplant patients. DESIGN: Right-sided heart septum biopsies and plasma samples were routinely saved in patients (eight males and one female, aged 48 +/- 6 years [mean +/- SEM], range 19 to 58). Observation time was one to 35 months involving one to 10 examinations. RESULTS: Average heart and plasma Q were 0.33 +/- 0.04 mg/g, range 0.06 to 0.58, and 0.65 +/- 0.10 mg/L, range 0.20 to 1.08, respectively. Corresponding values for those with only plasma E analyzed were 0.39 +/- 0.03 mg/g and 0.70 +/- 0.10 mg/L, respectively. Plasma E averaged 7.7 +/- 1.7 mg/L, range 4.6 to 11.3. There were no differences between patients in stable condition and healthy persons in heart and plasma Q, whereas plasma E corresponded to only 64% of the mean in healthy persons. On an individual level a relationship was present between heart and plasma Q. For high plasma Q, heart Q appeared to be saturated. In four patients, from whom plasma samples were taken close to a fatal complication, plasma Q averaged 0.42 mg/L (P < 0.01). CONCLUSIONS: Well controlled heart transplant patients had normal heart and plasma Q, whereas plasma E was depressed. Muscle and plasma Q became depressed, particularly with rejection episodes and/or infections.

Adult↗
PubMed1997

Muscle characteristics in effort angina before and after CABG.

Seven males with effort angina undertook graded ergometer tests and had muscle biopsies taken from their vastus lateralis muscle before, and three and six months after coronary bypass surgery. Muscle fibre composition (percentage of slow twitch fibres), ubiquinone (vitamin Q), and oxidative and fermentative enzyme activities were determined. After six months, muscle ubiquinone and oxidative enzymes were still depressed, indicating sustained muscle trauma. The only peripheral changes were that muscle lactate dehydrogenase and its skeletal muscle-specific subunits and isozymes were increased 35% to 40% (P < 0.001) three to six months postsurgery. Onset of blood lactate accumulation (2.0 mmol/L), symptom-limited ('maximal') exercise and peak blood lactate increased linearly over time (r = 0.52, P < 0.05; r = 0.63, P < 0.01; and r = 0.76, P < 0.001, respectively). It is suggested that the initial physical performance increase was due to improved circulatory capacity, oxygen delivery and lactate efflux, whereas the increased fermentative capacity ('anaerobic power') first contributed after a lag of three or more months. Whether the muscle histochemical changes reflected a healing process (recovery) is speculative.

Angina Pectoris↗
PubMed1996

Muscle fibers, ubiquinone and exercise capacity in effort angina.

Seventeen male patients with ischaemic heart disease (IHD) and effort angina performed OBLA exercise stress tests (set to 2.0 mmol x l-1). They had muscle biopsies from the vastus lateralis muscle the day before coronary by-pass grafting, and from the internal and external intercostal, diaphragm and gastrocnemius muscles during surgery. They had a low WOBLA (83 +/- 6 W, mean +/- 1 S.E.M), WOBLA corresponded to 79 +/- 4% (% WOBLA) of WSL (symptom limited or 'maximal' capacity = 111 +/- 11 W). Peak blood lactate concentration averaged 2.9 mmol x l-1. Muscle fibre composition disclosed a depressed percent slow twitch (ST or 'red') muscle fibres in the vastus lateralis and intercostal muscles (%ST). The diaphragm and gastrocnemius muscles had normal %ST. Intercostal muscles had elevated values for the fast twitch muscle fibre (FT) subgroup FTa indicative of endurance adaptation. The vastus lateralis, gastrocnemius and diaphragm muscles had normal muscle ubiquinone (UQ) contents, whereas the intercostals were depleted. Plasma contents of the antioxidants UQ and alpha-tocopherol were low as compared to healthy man.

Aged↗
PubMed1993

Heart muscle ubiquinone and plasma antioxidants following cardiac transplantation.

Nine patients who underwent heart transplantation (one female; average age 48 +/- 11, range 19-58 years) were followed in respect to contents of right-sided heart septum, blood and plasma ubiquinone (UQ), plasma alpha-tocopherol (alpha T), and plasma free cholesterol (FC). In contrast to healthy persons, substantial inter- and intraindividual variations were observed; individually low values were seen with rejection. Heart muscle UQ in well-treated patients averaged 0.33 +/- 0.08, range 0.06-0.58 micrograms mg-1 (0.38 +/- 0.09 mumol g-1 dry weight) and was not different from healthy individuals. Plasma UQ, alpha T; and FC averaged 0.63 +/- 0.33 micrograms ml-1 (P < 0.05 versus sedentary controls), 8.1 +/- 4.0 micrograms ml-1 (P < 0.01), and 0.52 +/- 0.23 mg ml-1 (P < 0.05). Corresponding molar values were 0.73 +/- 0.37 (UQ), 2.0 +/- 1.1 mumol l-1 (alpha T), and 1.42 +/- 0.54 mmol l-1 (FC). Blood and plasma UQ values were identical. A saturation like relationship was found between heart and blood UQ:blood contents below 0.7 micrograms ml-1 (0.8 mumol l-1) corresponded to markedly lowered heart contents. In four patients in whom blood samples were taken close to a fatal complication it averaged 0.42 micrograms ml-1 (0.49 mumol l-1, P < 0.01). When low heart muscle and blood ubiquinone were present, other variables such as left ventricle cardiac output or cycle ergometer performance was markedly impaired. Plasma UQ and alpha T covaried with a marker of the lipoidal deposit volume, plasma FC.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Ischaemic heart disease, skeletal muscle fibres and exercise capacity.

Twenty-eight male patients with ischaemic heart disease (IHD) performed OBLA (onset of blood lactate accumulation) exercise stress tests and had muscle biopsies taken from their vastus lateralis muscle the day before coronary bypass grafting. All 28 patients showed the same exercise performance pattern as compared to healthy sedentary, age-matched, controls: a low exercise intensity eliciting a blood lactate concentration of 2.0 mmol x l-1 (WOBLA), WOBLA corresponded to a high fraction (% WOBLA) of WSL (symptom limited or 'maximal' capacity), and a low peak blood lactate concentration. The high % WOBLA and low peak blood lactate indicated a reduced glycogenolytic capacity ('anaerobic' performance). Muscle fibre composition disclosed a high mean value of fast twitch (FT), type II or 'white' muscle fibres, as compared to sedentary healthy controls. This indicated that this patient group constituted an extreme subgroup of the age-matched population. The distorted muscle fibre composition in IHD could reflect both heredity as well as adaptation to physical inactivity, degenerative cytosolic properties, etc. Muscle and blood contents of a mitochondrial electron translocator and nonspecific radical scavenger, ubiquinone or coenzyme Q10(CoQ10), were low, which coincided with an elevated frequency of the fibre subgroup FT(c). The presence of the FT(c) fibre type is assumed to reflect histological trauma.

Adult↗
PubMed1989

Results of the first 100 patients who received Symbion Total Artificial Hearts as a bridge to cardiac transplantation.

Between August 8, 1985 and April 1, 1988, 100 patients in 22 centers underwent Symbion Total Artificial Heart (TAH) (Symbion, Inc., Salt Lake City, Utah) implantation as a bridge to cardiac transplant. Thirty patients received the Symbion J7-100, and 70 patients received Symbion J7-70 implants. Eighty-seven patients were men and 13 were women; mean age was 42 years, and mean weight was 73 kg. The time spent on the device ranged from 1 to 243 days, for a mean of 23 days. Sixty-eight patients underwent cardiac transplantation, with a 69% 30-day survival rate and a 46% (31 of 68) long-term survival rate. The majority of the patients had ischemic (52) or idiopathic (36) cardiomyopathies. Indications for implantation of the TAH occurred most frequently in patients whose condition deteriorated while awaiting transplant (34) or who were admitted in acute cardiogenic shock (27). There was an 8.7% incidence of thromboembolic events (four cerebrovascular accidents, five transient ischemic attacks). Multivariant analysis was performed to determine the effect of various factors on the patients' ability to undergo transplantation and then ultimate survival. The results indicate a need for further clinical investigation in patient selection and appropriate timing for implantation of the TAH.

Adult↗
PubMed1987

Hemostatic disturbances associated with implantation of an artificial heart.

Coagulation and platelet parameters have been assessed following implantation of a Jarvik 7 artificial heart. Initially an ongoing intravascular coagulation could not be overcome with heparin and coumarin. The in vivo formation of thromboxane A2 (as monitored by measurement of the major urinary metabolite) was increased 3-4 fold. Administration of aspirin every second to third day reduced the thromboxane formation dramatically. In parallel to this, the intravascular coagulation subsided, the demand for heparin decreased considerably and the clinical condition of the patient improved. These events provide evidence for a direct link between thromboxane formation and the coagulation cascade. The thromboxane formation was insufficiently suppressed around the 110th postoperative day. Two weeks later the patient suffered a cerebral embolus, followed by a bleeding in the embolized area. This case illustrates the applicability of antiplatelet treatment when the need for efficient antithrombotic treatment is especially pronounced. Aspirin, however, is not the ideal drug for this purpose.

Blood Coagulation Tests↗
PubMed1987

Subacute rupture of the free left ventricular wall following acute myocardial infarction. Report of an atypical case with successful surgical repair.

In previously published cases of subacute or sealed postinfarction rupture of the free left ventricular wall, the patients presented a clinical picture of sudden shock and tamponade. Our patient, a 64-year-old man, suffered renewed chest pain on the fourth postinfarction day and went into cardiogenic shock, which was pharmacologically reversible. There were no bed-side signs of tamponade and the ECG showed the pattern of acute pericarditis, both features in contrast to previously reported cases in the literature. Echocardiography demonstrated localized fluid in the pericardial sac and a puncture revealed non-coagulating blood. The patient was successfully operated on. At surgery a small rupture sealed by blood clots was demonstrated in the infarcted inferior wall of the left ventricle.

Electrocardiography↗
PubMed1983

The influence of open-heart surgery during extreme hemodilution on the hemostatic mechanism in the dog.

12 Labrador retriever dogs had mitral disc valves implanted during cardiopulmonary bypass (CPB) with extreme hemodilution, obtained with preoperative blood withdrawal, the use of blood-free priming fluid during perfusion, and retransfusion of autologous blood. Before operation, platelet adhesiveness as well as the reactivity of the intrinsic and extrinsic coagulation systems were markedly higher than in man. During CPB, the number of functioning platelets was very low, but increased after retransfusion, and were after 4 h twice as high as in 7 human patients who received aortic disc valves during CPB with extreme dilution. The extrinsic coagulation system also reacted much faster during and after CPB in the dogs, and heparin activity was rapidly neutralized and intrinsic coagulation normalized in them. Intravascular coagulation did not occur, and more hemolysis was induced in the dogs than in the patients. 3 of the dogs died from valve thrombosis within 24 h. The high reactivity of platelets and coagulation systems in the dog makes the canine model a very difficult one for experimental open-heart surgery because of a strong tendency to thrombosis.

Animals↗
PubMed1983

Mitral disc valve implantation in the dog: early and late valve thrombosis and its prevention.

Valve thrombosis and its prevention was studied in 33 Labrador retriever dogs who received Hall-Haster mitral disc valves during extracorporeal circulation with extreme hemodilution. Three antithrombotic regimes were used. (1) 12 dogs received 1 g heparin preoperatively, and Warfarin tablets from the first postoperative day. Anticoagulation was controlled with thrombotest (TT), aiming at 20-25% of normal coagulation activity. (2) 9 dogs received 10 mg of heparin intravenously hourly for 10 h, and intravenous injections of Warfarin daily, aiming at TT values of 15-20%. (3) The last 12 dogs had continuous heparin infusion for 24 h, and Warfarin injections before as well as after the operation in doses sufficient to reduce the TT to 10-15% of normal. Stable anticoagulation was very difficult to maintain. Only 15 dogs survived the first postoperative day, 7 were alive after 4 weeks. 7 early and 5 late deaths were due to valve thrombosis. All three antithrombotic regimes were equally ineffective in preventing thrombosis, and more intensive antithrombotic prophylaxis is needed to make the canine model suitable for experimental open-heart surgery.

Animals↗
PubMed1983

A 5 year experience with the Medtronic-Hall disc valve prosthesis.

Throughout the period from 1977 to 1982, 426 patients underwent aortic valve replacement, 106 patients underwent mitral valve replacement, and 56 patients had double valve replacement with the Medtronic-Hall (previous Hall-Kaster) valve. Early and late mortality was 4% and 9% in the aortic group, 8% and 11% in the mitral group, and 7% and 13% in the double valve group. There was an 81% probability of surviving 5 years after aortic or double valve replacement, and a 75% probability of surviving 5 years after mitral valve replacement. Postoperative follow-up studies revealed low pressure gradients across the aortic as well as across the mitral valve prosthesis, irrespective of valve size. Exercise studies indicated good tolerance of increasing cardiac output during strenuous exercise tests in patients with aortic valve prosthesis. Thromboembolic complications in the aortic series included two cases of valve thrombosis and 11 thromboembolic episodes in 10 patients. In the mitral series an aspergillus thrombus was found on the valve at autopsy in a patient dying from multiple cerebral aspergillus abscesses, and five thromboembolic episodes occurred in four additional patients in the mitral series. In the double valve series there was one valve thrombosis and one patient had a thromboembolic episode.

Actuarial Analysis↗
PubMed1981

Haemodynamic changes with the administration of nitrous oxide during coronary artery surgery.

Haemodynamic responses to 50% nitrous oxide in oxygen during coronary artery surgery were investigated in 10 patients. Morphine, diazepam and pancuronium were given intravenously as both induction and maintenance anaesthesia. A significant decrease was seen in heart rate, arterial pressure, pulmonary artery pressure, heart rate-systolic arterial pressure product, peripheral vascular resistance, left ventricular end-diastolic pressure, dP/dT of the left ventricle and resistance as measured in the graft to the left anterior descending coronary artery (LAD). No variations occurred in cardiac output, stroke volume, flow in the LAD-graft, pulmonary artery pressure or heart rate-systolic pulmonary artery pressure product or in dP/dT of the right ventricle. Pulmonary vascular resistance increased. It was concluded that left ventricular performance did not decrease and that no deterioration of the oxygenation to the myocardium seemed to occur.

Adult↗
PubMed1978

Obstructic characteristics of Björk-Shiley, Hancock, and Lillehei-Kaster prosthetic mitral valves in the immediate postoperative period.

The flow obstruction in mitral valve implants was studied in the immediate postoperative period in 19 patients with Björk-Shiley, Hancock, or Lillehi-Kaster prosthetic mitral valves. The effective valve area (Ae) was used as a measure of the flow obstruction. The blood velocity in the implants was estimated with a non-invasive ultrasound Doppler system. The cardiac output was determined with an indwelling thermodilution catheter. The collected data allowed the determination of Ae. Multiple determinations of Ae, at various cardiac outputs and pulse rate were generally performed in each patient during the first 2--3 postoperative days. The investigation demonstrated that the method employed was useful for the study of mitral implant performance. The obtained values of Ae demonstrated that the flow obstruction in presthetic mitral valve implants is frequently considerable.

Aged↗