Acute effects of indomethacin on cerebral hemodynamics and oxygenation

Although an indomethacin-induced decrease of brain perfusion in preterm infants has been well established, the acute effects of this vasoactive drug on cerebral hemodynamics and oxygenation are not well documented. Using near infrared spectroscopy we monitored in 6 very preterm infants changes in cerebral blood volume (delta CBV) and cytochrome oxidase concentration (delta Cytaa3), used as relative measures of changes in brain perfusion and as an indicator for cellular oxygenation of brain tissue, during and up to 1 h after indomethacin infusion. delta CBV showed a quick blood-pressure-related increase as compared to baseline (preindomethacin values) during indomethacin infusion (averaged maximal increase 13%), followed by a sharp decrease below baseline values (averaged maximal decrease 24%). There was a sustained recovery to baseline during the registration period. delta Cytaa3 showed a small, early increase in 4 of 6 babies, followed by a substantial decrease below baseline in 5 babies. delta Cytaa3 showed only a partial recovery in those 5 babies during the study period. We conclude that a therapeutic dose of indomethacin may cause substantial swings in brain perfusion and a marked and rather longstanding decrease in Cytaa3, suggesting a decrease in cellular oxygenation of brain tissue. Awareness of these effects may be important in sick preterm babies during periods of pulmonary and cardiac instability.

Assessment of copper nutritional status

Despite increased interest in the role of copper deficiency in clinical problems and an increased understanding of the physiological roles of copper, the diagnosis of a marginal deficiency has not been perfected. The use of non-standardized procedures and the effects of factors other than copper nutriture have impeded identification of the "ideal" indicator of copper nutritional status in adult humans. The specific activity of copper enzymes, or of copper-containing enzymes in blood cells, such as erythrocyte superoxide dismutase and platelet or leukocyte cytochrome c oxidase, may be a better indicator of metabolically active copper stores than the serum concentration of copper or ceruloplasmin, because the enzyme activities are sensitive to changes in copper stores and are not as sensitive to factors not related to copper nutriture. A single index, such as serum copper concentration, is inadequate for assessing the total body copper nutriture of an individual and must be supported by corroborating evidence.

Reduced platelet cytochrome c oxidase activity in Alzheimer's disease

We evaluated a simplified method for preparation and analysis of platelet cytochrome c oxidase activity in Alzheimer's disease (AD) and control patients. Mean cytochrome c oxidase activity in controls (n = 17) was 0.233 sec-1/mg whereas mean cytochrome c oxidase activity in Alzheimer patients (n = 19) was 0.193 sec-1/mg, p = 0.033. Complex III (ubiquinol:cytochrome c oxidoreductase), complex II (succinic dehydrogenase), and citrate synthase were all assayed as internal controls and were not significantly different in controls and Alzheimer patients. There is a relatively specific loss of platelet cytochrome c oxidase activity in Alzheimer disease patients.

[Specific enzyme diagnosis in mitochondrial myopathies and encephalomyopathies]

Mitochondrial enzyme activities (cytochrome c-oxidase = COX, carnitine acyl-transferase = CAT, citrate synthase = CS, lipoamide dehydrogenase = lipDH from the pyruvate-dehydrogenase complex, lactate dehydrogenase = LDH, and malate-dehydrogenase = MDH) were measured from progressive myopathy/encephalomyopathy. Cytochrome oxidase (COX) deficiency was detected from muscle or liver tissues, adult type of COX defectus had been diagnosed in 1 case and infantile type in further 6 cases. The 3 familial atactic children showed decreased activity of carnitine acetyl-transferase, too.

Platelet mitochondrial function in Leber's hereditary optic neuropathy

We report the effect of the 11,778 and 3460 base pair mitochondrial DNA mutations, found in Leber's hereditary optic neuropathy (LHON), on platelet mitochondrial respiratory chain enzyme activity. We measured respiratory chain enzyme activities in platelets from 4 patients with the 3460 mutation, 17 patients with the 11,778 mutation and compared them with those of 41 healthy age-matched controls. We observed a 67% (P < 0.001) reduction in the mean NADH CoQ1 reductase (complex I) activity of the 3460 group compared to the control group. It has been shown previously that platelet mitochondrial biochemistry is affected by cigarette smoking. A significant reduction (25%, P < 0.03) in the mean complex I activity of the 11,778 group was only observed when the non-smokers within that group were compared to the non-smoking controls. The effect of smoking observed in this study may explain why previous workers have not observed a decrease in complex I activity associated with the 11,778 mutation. There was no significant change in the activity of complexes II/III or IV with either of these mutations. There was a significant increase (26%, P < 0.008) in citrate synthase (CS) activity with the non-smoking 11,778 group compared to the non-smoking control group, rising to 40% (P < 0.002) in those with this mutation who smoked. This reflects an increase in mitochondrial mass with the 11,778 mutation. This effect was not observed with the 3460 mutation even though the complex deficiency was much more severe.

Abnormal platelet mitochondrial function in patients affected by migraine with and without aura

To investigate energy metabolism in migraine, we determined platelet mitochondrial enzyme activities in 40 patients with migraine with aura and in 40 patients with migraine without aura during attack-free intervals and in 24 healthy control subjects. NADH-dehydrogenase, citrate synthase and cytochrome-c-oxidase activities in both patient groups were significantly lower than in controls (p < 0.01), while NADH-cytochrome-c-reductase activity was reduced only in migraine with aura (p < 0.01). No alteration in succinate-dehydrogenase was observed. Monoamine-oxidase activity differed between sexes (p < 0.05) but within each sex group no difference was observed between patients and controls. We hypothesize that the defect in mitochondrial enzymes observed indicates a systemic impairment of mitochondrial function in migraine patients.

[Near-infrared spectroscopy--a new method for non-invasive monitoring of cerebral hemodynamics]

Non-invasive techniques allow monitoring in prematures and newborns with the maxime of "minimal handling". Cerebral changes in oxi- and deoxihemoglobin and in total hemoglobin, which reflects the intracranial blood volume, can be monitored continuously by near infrared spectroscopy (NIRS) for the first time. As derived parameter the cerebral blood flow can be determined. With reservations the method allows to get a view of the cellular level by recorded changes of the cytochromeoxidase. This article gives a survey of the physics, the technique and shows the clinical application of the method.

Smoking and mitochondrial function: a model for environmental toxins

Defects of the human mitochondrial respiratory chain have been associated with several diseases including, most recently, certain neurodegenerative disorders. Several studies have used platelet mitochondrial function as a means to determine the potential contribution of respiratory chain defects to the pathogenesis of Parkinson's disease. Platelet biochemistry is subject to modulation by numerous factors that may circulate in the blood, including environmental agents, some of which may be relevant to mitochondrial dysfunction and neuronal toxicity. We measured mitochondrial respiratory chain enzyme activities in platelets from 18 normal healthy non-smoking controls and compared them with those from 23 similarly healthy cigarette smoking individuals. A 24% decrease (p < 0.02) was observed in the mean NADH CoQ1 reductase (complex I) activity of the smoking group compared with that of the non-smoking group. There was no significant change in the activity of any of the other respiratory chain enzymes. This is the first demonstration in vivo of mitochondrial inhibition by a common environmental agent. The results offer a novel mechanism of action for the cellular toxicity, or even mutagenicity, associated with cigarette smoking. In addition, these data have important implications for the interpretation of platelet mitochondrial complex I activities in disease states. They are particularly relevant to our interpretation and understanding of the complex I deficiency in Parkinson's disease platelets.

A microtiter plate assay for cytochrome c oxidase in permeabilized whole cells

Defects of the mitochondrial respiratory chain often involve dysfunction of cytochrome c oxidase, the terminal component of this chain. We have developed a microassay, suitable for various cell types, which can be carried out in microwell plates. This assay has advantages over the traditional spectrophotometric method as only a small number of cells are used, without the need for mitochondrial fractionation. This makes the assay faster and use of the microtiter plate allows many samples to be screened simultaneously. We demonstrate that lowered levels of cytochrome c oxidase activity can be detected in patients' blood samples, avoiding the necessity for a more invasive tissue biopsy. This cytochrome c oxidase assay is also suitable for use as an intramitochondrial marker for monitoring the effect of mitochondrial translation inhibitors or effectors which modulate mitochondrial biogenesis and could be used for assessing the effect of mitochondrial DNA mutations.

Assessment of copper status: effect of age and gender on reference ranges in healthy adults

We measured major indices related to copper nutritional status in 55 men and 86 women between ages 20 and 83 years who were in apparent good health. Plasma copper concentrations and both immunoreactive and enzymatically measured ceruloplasmin were significantly higher in women than in men and were higher in women taking oral contraceptives. Plasma copper, immunoreactive ceruloplasmin, and cytochrome-c oxidase in platelets and mononucleated leukocytes tended to increase with age. The ratio of enzymatic to immunoreactive ceruloplasmin, erythrocyte superoxide dismutase, and 67Cu uptake by erythrocytes were not significantly affected by either age or gender. Thus, factors other than copper nutriture--such as age, gender, and hormone use--need to be considered when using many of these indicators to evaluate copper nutritional status.

Respiratory chain enzyme activities in lymphocytes from untreated patients with Parkinson disease

Respiratory chain enzyme activities were studied in lymphocytes from patients with Parkinson disease (PD) (n = 16) and age-matched control subjects (n = 15). The patients had received no therapy before the study was conducted. Complex I, III, and IV activities were significantly lower (P < 0.05) in patients than in control subjects. A complex I defect was found in one patient, whereas complex IV was defective in another. Two patients had combined defects of both complexes. The use of lymphocytes for investigating the respiratory chain enzymes provides an easy, noninvasive method to assess mitochondrial function in patients with PD. Furthermore, our study supports the hypothesis that a biochemical defect in the respiratory chain may be involved in the pathogenesis of PD.

Effects of age and sex on copper absorption, biological half-life, and status in humans

Healthy, free-living men and women aged 20-83 y (n = 127) were studied to determine the effects of age and sex on copper absorption, biological half-life (BH), and status. Copper absorption was greater in women (71%) than in men (64%) aged 20-59 y (P = 0.02), but did not differ in men and women aged 60-83 y. BH of 67Cu ranged from 13 to 33 d and differed between men and women aged 20-59 y (P = 0.006), but not between men and women aged 60-83 y. Plasma copper, enzymatic ceruloplasmin (Cp), and immunoreactive (RID) Cp were significantly higher in women than in men (P < 0.005), but superoxide dismutase (SOD) and in vitro 67Cu uptake by red blood cells did not differ. Plasma copper, RID Cp, and cytochrome oxidase in platelets and mononuclear cells were significantly affected by age (P < 0.005). Oral contraceptives elevated plasma copper, enzymatic Cp, and SOD activity but not copper absorption and BH in women aged 20-39 y. Copper intake from self-selected diets was 0.9-1.2 mg/d for women and 1.2-1.3 mg/d for men, but net copper absorption (micrograms Cu.kg body wt-1.d-1) did not differ. Thus, dietary copper intake requirements may differ between men and women.

No evidence for reduced thrombocyte cytochrome oxidase activity in Alzheimer's disease

We measured cytochrome oxidase activity in thrombocytes from patients with senile dementia of the Alzheimer type. We found no decrease in enzyme activity in Alzheimer's disease patients when compared with patients with multi-infarct dementia, with young control donors, and with age-matched control donors.

[The influence of umbilical cord compression on the fetal brain--an animal experiment using laser spectroscopy]

In order to evaluate the influence on the fetal brain due to compression of the umbilical cord biochemical and biophysical changes were traced during defined occlusions of 60 sec by means of NIR laser spectroscopy. Synchronously blood samples were drawn intermittently from a catheter positioned in the A. carotis and analysed for blood gases. The saturation values measured in the fetal blood correlated significantly with the dates of the HbO2 tracing of the NIR-system (r = 0.81, p less than 0.001). After induced occlusion of the umbilical cord a reproducible pattern of the NIR tracing occurred. While an immediate fall in HbO2 occurred, a synchronous rise in desaturated Hb was observed. For the changes of the cytochrome aa3 we detected a minor decrease that occurred with a lag time. Additionally there was an indication of a major change of blood volume as the total Hb content augmented during each compression. We concluded: Changes of Hb-saturation in the fetal blood are immediately indicated by NIR-laser spectroscopy. During cord occlusion of 60 sec. the intracellular oxygenation decrease only after a significant lag time and are reversible and furthermore it leads to a reproducible change of intracerebral blood volume.

Cytochrome oxidase deficiency in Alzheimer's disease

We assayed cytochrome oxidase and other electron transport chain activities in platelet mitochondria isolated from patients with Alzheimer's disease (AD). Five of 6 patients had striking reductions of platelet cytochrome oxidase activity (patient mean, 83.72 +/- 82.99 nmol/min/mg; control mean, 167.14 +/- 36.21 nmol/min/mg; n = 8). Other electron transport chain catalytic activities were not significantly different than control values. AD may be a systemic illness, a primary defect in cytochrome oxidase may be pathogenically important in its production, and the mitochondrial genes encoding cytochrome oxidase subunits may be important in producing the defect.

[Cytochrome oxidase activity of peripheral blood leukocytes in patients with diffuse toxic goiter]

Patients with diffuse toxic goiter showed a distinct reduction of the cytochromoxidase activity in the peripheral blood leucocytes. The degree of reduction of the cytochromoxidase activity in the leucocytes depended on the severity of the clinical course and degree of increase of the thyroid gland. Results of determination of the cytochromoxidase activity of leucocytes in patients with diffuse toxic goiter in association with other clinico-laboratory data reflect the severity of the clinical course of the disease, the hypoxia degree and efficacy of instituted treatment.

[Evaluation of a rapid diagnosis of congenital lactic acidemia by transported peripheral blood samples]

The usefulness of a rapid diagnosis of congenital lactic acidemia was investigated using peripheral blood samples from 40 patients with lactic acidemia which had been transported from the hospitals in every part of Japan. Platelets and monocytes were separated, and the rates of decarboxylation of pyruvate and activities of enzymes involved in pyruvate metabolism were measured. The activity of phosphoenolpyruvate carboxykinase in monocytes was relatively stable. However, [1-14C] pyruvate and [3-14C] pyruvate decarboxylation rates and cytochrome c oxidase activity in platelets and pyruvate carboxylase activity in monocytes were unstable and decreased during the transportation of blood samples. Therefore, in order to diagnose the enzyme defects, it was necessary to compare the values for patients with those for control subjects who were simultaneously examined. Using this method, a patient with pyruvate dehydrogenase complex deficiency was found in the 40 patients with congenital lactic acidemia.

Myxothiazol resistance in human mitochondria

We have investigated electron transfer activities of respiratory chain complexes in platelet mitochondria of a patient with intermittent ataxia and lactic acidosis who was previously reported to be deficient in the E1 (decarboxylase) component of the pyruvate dehydrogenase complex. Electron transfer from succinate to cytochrome c was normal, but the mitochondria exhibited moderately decreased (63% of control) quinol: cytochrome-c oxidoreductase activity, suggesting a defect in complex III. Consistent with some perturbation in complex III, electron flux through complex III was resistant to inhibition by myxothiazol compared to normal controls. In contrast, titration with antimycin revealed a less abnormal pattern of inhibition. The extreme specificity of myxothiazol binding at or near the quinol oxidase domain of mitochondrial cytochrome b, i.e., b-566, suggests a defect in this region of complex III which may perturb the kinetics or thermodynamics of quinol oxidation in the complex. These data suggest that the patient's illness results from a mutation in the quinol oxidase domain of mitochondrial cytochrome b (b-566).

[Evaluation of the adequacy of hypotensive therapy based on the status of the tissue oxygen system and serum lactate dehydrogenase and cytochrome oxidase activities in patients with hypertension]

Parameters of tissue oxygen regime measured by polarography and serum lactate dehydrogenase (LDG) and cytochrome oxidase (CO), oxidation-reduction enzymes, were studied in 23 patients with stable hypertension of various hemodynamic types. The nature of the tissue oxygen regime and changes observed in the isoenzymic spectra of LDG and CO were found to be associated with BP levels, hemodynamic types and BP reduction degree. The time course of these values may be useful in assessing whether the antihypertensive therapy is appropriate and in determining an optimal level of BP decrease.

Development of the phagocytic and cidal capacity during maturation of myeloid cells: studies on cells from patients with chronic myelogenous leukaemia

Myeloid cells from peripheral blood of patients with chronic myelogenous leukaemia were isolated and fractionated by density gradient centrifugation using Lymphoprep gradient followed by discontinuous Percoll gradients. Six fractions were obtained, each enriched in one of the morphologically identifiable types of myeloid cells from myeloblasts to polymorphonuclear neutrophils. Each of these cell types were functionally and biochemically characterized. The development of the capacities for phagocytosis and killing of yeast cells and the ability to generate a respiratory burst of phagocytosis correlated closely with the content of cytochrome b and vitamin B12-binding protein, a marker of specific granules. These results support the notion that the specific granules provide the developing neutrophil with components which are essential for its microbicidal activity.

[Criteria for assessing the adequacy of a hypotensive effect by data on the lactate dehydrogenase and cytochrome oxidase isoenzyme spectra of patients with different forms of arterial hypertension]

A study of associations between lactate dehydrogenase and cytochrome oxidase isoenzymes and total cytochrome oxidase activity, on the one hand, and the type of arterial hypertension, the magnitude of blood pressure and its response to treatment, on the other, was carried out in 143 patients with varying stages of essential hypertension and in renal hypertension. The examined parameters were found to be valuable indicators of adequate hypotensive effect and an optimum BP fall. A 20-24% BP drop below the baseline is optimal for patients with renal hypertension. A 30% BP drop is acceptable for patients with stable essential hypertension. Attaining normal BP level is acceptable and desirable for cases of labile essential hypertension.