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Biomedical subjects

J C Fischer

Publications and source records attributed to J C Fischer.

At least 19 recordsLinked to original sources
PubMed2001

Safe discharge from the cardiac emergency room with a rapid rule-out myocardial infarction protocol using serial CK-MB(mass).

OBJECTIVE: To determine whether a new protocol, using a rapid and sensitive CK-MB(mass) assay and serial sampling, can rule out myocardial infarction in patients with chest pain and decrease their length of stay in the cardiac emergency room without increasing risk. DESIGN: The combined incidence of cardiac death and acute myocardial infarction at 30 days, six months, and 24 months of follow up were compared between patients discharged home from the cardiac emergency room after ruling out myocardial infarction with a CK-MB(activity) assay in 1994 and those discharged home after a rapid CK-MB(mass) assay in 1996. SETTING: Cardiac emergency room of a large university hospital. PATIENTS: In 1994 and 1996, 230 and 423 chest pain patients, respectively, were discharged home from the cardiac emergency room with a normal CK-MB and an uneventful observation period. RESULTS: The median length of stay in the cardiac emergency room was significantly reduced, from 16.0 hours in 1994 to 9.0 hours in 1996 (p < 0.0001). Mean event rates in patients from the 1994 and 1996 cohorts, respectively, were 0.9% (95% confidence interval (CI) -0.3% to 2.1%) v 0.7% (95% CI -0.1% to 1. 5%) at 30 days, 3.0% (95% CI 0.8% to 5.2%) v 2.8% (95% CI 1.2% to 4. 4%) at six months, and 7.0% (95% CI 3.7% to 10.3%) v 5.7% (95% CI 3. 5% to 7.9%) at 24 months. Kaplan-Meier survival analysis showed no difference in mean event-free survival at 30 days, six months, and 24 months of follow up. CONCLUSIONS: Using a rule-out myocardial infarction protocol with a rapid and sensitive CK-MB(mass) assay and serial sampling, the length of stay of patients with chest pain in the cardiac emergency room can be reduced without compromising safety.

Adult↗
PubMed2000

Different time frames for the occurrence of elevated levels of cardiac troponin T and C-reactive protein in patients with acute myocardial infarction.

The baseline plasma level of C-reactive protein (CRP) is considered to be a parameter for risk stratification in patients with an acute coronary syndrome, independent of the level of cardiac troponin T (cTnT) or cardiac troponin I. However, myocardial tissue necrosis following prolonged arterial occlusion also induces release of CRP. Both phenomena may have their own kinetic behaviour with respect to changes in concentration of CRP. Therefore, in this study the time frame after onset of symptoms for measurement of CRP as an independent parameter is established. For this purpose, we evaluated patients with proven myocardial damage due to acute myocardial infarction (AMI) with respect to changes of creatine kinase (CK)-MB mass, cTnT and CRP during 24 hours after onset of symptoms. Our results show that two subgroups can be discerned in patients with AMI: those with initially normal and those with already elevated concentration CRP on admission. Furthermore, based on the results of this study we conclude that for use of CRP as an independent prognostic parameter in patients with acute coronary syndrome, CRP should be measured in blood samples drawn as early as possible after the onset of symptoms to avoid contribution of a process of myocardial tissue necrosis, whereas estimation of cTnT should be performed at 6-12 hours.

C-Reactive Protein↗
PubMed1999

Distribution of iron and manganese in the Seine river estuary: approach with experimental laboratory mixing.

The physico-chemical behaviour of iron and manganese has been observed during many surveys covering various hydrodynamic conditions in the Seine river estuary system. The results obtained confirm the non-conservative behaviour of these two metals. Generally, dissolved iron exhibits non-conservative removal and shows a rapid decrease in low salinity; it is moved from fresh waters with high concentrations to saline waters with very low concentrations. This can be attributed to the flocculation processes as confirmed by laboratory experiments. Dissolved manganese versus salinity curves exhibit a peak concentration in the low salinity zone. Laboratory mixing experiments have been undertaken comparing iron and manganese adsorption/desorption from suspended material versus salinity, using a series of water samples collected in the up-river and marine regions in order to assess the importance of particulate material and salinity on iron and manganese distributions. The salinity was controlled by varying the marine to fresh water ratio. The reaction kinetics aspect is developed in more detail for manganese in the last series of remobilization experiments starting from a stock of suspended particles collected in the upstream river site (Caudebec) in mixtures of waters, according to time and salinity. This study has allowed us to show that iron and manganese behaviour in the Seine estuary is strongly influenced: (i) by the high turbidity zone and by the presence of calcium carbonate which could stabilise the Mn(II) form; and (ii) by the increase of salinity, calcium, magnesium and suspended matter concentrations and by complex formation.

Calcium Carbonate↗
PubMed1996

Air travel and adults with cyanotic congenital heart disease.

BACKGROUND: Concern has been expressed that a reduction of partial oxygen pressure during flight in commercial aircraft may induce dangerous hypoxemia in patients with cyanotic congenital heart disease. METHODS AND RESULTS: To evaluate the validity of this concern, the transcutaneous SaO2 was measured in 12 adults with this type of heart disease and 27 control subjects during simulated commercial flights of 1.5 and 7 hours in a hypobaric chamber. Ten of those patients and 6 control subjects also were evaluated during two actual flights of approximately 2.5 hours in a DC-10 and an A-310, respectively. During the prolonged simulated and actual flights, the capillary blood pH, gases, and lactic acid were analyzed in the patients and during one of the actual flights also in the control subjects. During the simulated flights the SaO2 was at all times lower in the patients than in the control subjects. However, the maximal mean actual percentage decrease, as compared with sea level values, did not exceed 8.8% in either patients or control subjects. During the actual flights, this maximal decrease in the patients was 6%. In-flight reduction of the capillary PO2 was considerable in the control subjects but not in the patients. It is our hypothesis that the lack of a significant decrease of the PO2 in the patients might possibly be due to a high concentration of 2.3 diphosphoglycerate in the red cells. The flights had no influence on the capillary blood pH, PCO2, bicarbonate, or lactic acid levels in either patients or control subjects. CONCLUSIONS: Atmospheric pressure changes during commercial air travel do not appear to be detrimental to patients with cyanotic congenital heart disease.

2,3-Diphosphoglycerate↗
PubMed1996

Faecal nitrogen determination by near-infrared spectroscopy.

The well-known Kjeldahl method for the determination of faecal nitrogen is rather complex, time-consuming and expensive. Therefore, the use of near-infrared spectroscopy in determining the amount of nitrogen in faeces has been studied. To our knowledge we are the first to present the calibration equation for the determination of nitrogen with near-infrared spectroscopy. A good correlation (r = 0.96) was found between results from near-infrared spectroscopy and the Kjeldahl method. The imprecision of both methods was comparable. Once the rather laborious calibration has been performed, near-infrared spectroscopy is shown to be a very simple and rapid method for measuring nitrogen in faeces.

Adult↗
PubMed1995

Direct measurement of lipid peroxidation in submitochondrial particles.

The susceptibility of the polyunsaturated fatty acid parinaric acid (cis-PnA) to peroxidative damage with concomitant loss of its fluorescent character can be used to detect lipid peroxidation in a direct and sensitive way. The procedure, originally developed to measure peroxidation in lipid vesicles and erythrocyte membranes, has been adapted for the study of submitochondrial particles. Optimal conditions for the concentrations of cis-PnA (0.8 mol %), mitochondrial membrane (100 microM membrane phospholipid), and the radical generating system (50 microM NADH and 10 microM:1 mM Fe(III)-ADP) were established. In the absence of peroxidation inducing compounds, a stable fluorescent signal can be detected. Upon addition of NAD(P)H and ADP-Fe(III), lipid peroxidation starts, and the observed fluorescence decrease is a measure of peroxidation. Both NADH and NADPH were able to induce lipid peroxidation in submitochondrial particles in the presence of an iron chelate. The use of NADH resulted in higher rates of peroxidation compared with NADPH at the same concentration. Whereas the rate of NADH-induced lipid peroxidation was maximal at very low NADH concentrations (2.5 microM) and decreased when the concentration became higher, the NADPH-induced lipid peroxidation reaches saturation at 100 microM. NADH-induced lipid peroxidation in submitochondrial particles from different rat tissues (heart, skeletal muscle, and liver) resulted in a clear difference in peroxidation rates. The highest rates were observed in heart submitochondrial particles, while the lowest rates were obtained in submitochondrial particles derived from liver. Skeletal muscle submitochondrial particles showed intermediate rates of lipid peroxidation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate↗
PubMed1993

Rapid development of left main disease after coronary artery bypass grafting for failed angioplasty: a rare cause of postoperative angina.

We report a case of failed coronary angioplasty requiring urgent coronary artery bypass graft surgery. The return of angina pectoris early after surgery led to repeat catheterization, demonstrating a rapidly progressive stenosis of the left main coronary artery. This was treated successfully with coronary angioplasty. In patients with recurrent angina early after bypass surgery in whom angioplasty preceded surgery, acceleration of left main disease should be considered.

Angina Pectoris↗
PubMed1988

Disorders of the mitochondrial respiratory chain: clinical manifestations and diagnostic approach.

The clinical identification of patients with defects in the mitochondrial respiratory chain is almost impossible. We describe screening tests that should be performed in order to select those patients in whom a skeletal muscle biopsy should be carried out for more specific biochemical assays. The importance of performing in vivo function tests is stressed. The biochemical diagnosis in disorders of the respiratory chain is presented and the application of immunological methods discussed.

Biopsy↗
PubMed1987

Mitochondrial encephalomyopathy. Association with an NADH dehydrogenase deficiency.

A 17-year-old patient had a progressive hypokinetic-rigid syndrome and several other signs and symptoms that indicated central nervous system involvement. Biochemical studies revealed a reduced form of nicotinamide-adenine dinucleotide dehydrogenase deficiency in skeletal muscle. Clinical signs and symptoms, and their association with an established defect of energy metabolism, led us to classify this disorder as a mitochondrial encephalomyopathy of Leigh's type.

Adolescent↗
PubMed1986

Estimation of NADH oxidation in human skeletal muscle mitochondria.

Assay procedures are described for the detection of defects in the process of NADH oxidation by the respiratory chain in human skeletal muscle biopsy specimens. The procedures allow determination of rotenone-sensitive NADH: O2 oxidoreductase and NADH: ubiquinone-1 oxidoreductase activity not only in isolated mitochondria but also in post-nuclear supernatants. The use of ferricyanide as electron acceptor for estimation of NADH dehydrogenase activity is inadequate when only applied on a disrupted mitochondrial preparation.

Cytochrome c Group↗
PubMed1986

Waveform analysis applied to laser Doppler flowmetry.

Laser Doppler flowmetry (LDF) has been found useful in monitoring free flaps. In the present study, waveform analysis has been applied to the LDF waveform. Waveform changes were investigated in the microcirculation during varying degrees of arterial or venous occlusion in the saphenous island and flap of the dog and the human digit. The quantitative analysis of laser Doppler flowmetry waveform allows for the diagnosis of arterial occlusion or venous occlusion and their differentiation.

Animals↗
PubMed1986

Dynamic computer tomography determining the patency of buried free flaps.

Numerous methods exist for monitoring the patency of cutaneous free flaps. Monitoring the patency of microvascular anastomosis in buried free flaps are limited. The present case report is of a 39-year-old female with Rhomberg's disease who underwent an abdominus rectus muscle free flap to correct the contour deformity of the right face. Dynamic CT scan was performed on the sixth postoperative day. Plots of the rate of change of density of the free flap were compared to an adjacent muscle of the face. Dynamic CT scanning provides a high degree of resolution of the free flap, the ability to examine the entire free flap, and the ability to determine the patency of buried free flap.

Adult↗
PubMed1986

A mitochondrial encephalomyopathy: the first case with an established defect at the level of coenzyme Q.

A patient is presented who had therapy-resistant epileptic seizures from the 7th day of life. Examination at the age of 17 months revealed a mentally retarded boy with epileptic seizures, generalised myoclonic contractions, and abnormal ocular movements. A cerebral CT scan showed central and cortical atrophy. Lactate levels in serum, cerebrospinal fluid and urine were elevated, the pyruvate level was raised in serum. A quadriceps muscle biopsy revealed aspecific morphologic signs of a myopathy. Biochemical analysis showed decreased substrate oxidation rates in the mitochondria associated with low rates of ATP production. Total and free carnitine levels were decreased. Investigation of the respiratory chain revealed a defect in the proximal part of respiratory chain involving the region of coenzyme Q. Based on clinical and chemical data it is likely that the patient is suffering from a multi-system disorder.

Acidosis↗
PubMed1986

Disturbed oxidative metabolism in subacute necrotizing encephalomyelopathy (Leigh syndrome).

Several disorders of oxidative metabolism have been described in association with subacute necrotizing encephalomyelopathy (SNE) or Leigh syndrome. We present an eight-year-old girl with a mild spastic paraparesis and clinical deterioration on intercurrent infections. One sib died of SNE proven by autopsy. Biochemical examination of muscle tissue points to a disturbance in the process of oxidative phosphorylation due to a disturbed oxidation of NADH. The biochemical disorders associated with SNE are reviewed. The relation of SNE to the concepts of encephalomyopathy and mitochondriopathy is discussed.

Biopsy↗