Status of some free radical scavenging enzymes in the blood of myocardial infarction patients.

Pro-oxidant and anti-oxidant systems and their levels have significant roles in occlusive vascular diseases. In the present communication, we have measured the levels of some representative anti-oxidant enzymes in the blood of the patients of myocardial infarction after reperfusion and compared them to age and sex matched healthy persons. Our findings show that the activities of anti-oxidant enzymes (viz. SOD, catalase and glutathione reductase) are significantly decreased whereas there is significant increase in the levels of malonaldialdehyde (a marker of free radical-mediated damage) in the patients. The findings point out that ischemic myocardial disorders are associated with excessive free radical generation and free radical-mediated damage of lipids.

Effect of vitamin E on platelet enzymatic anti-oxidants in the patients of myocardial infarction.

Effect of administration of 600 mg. vitamin E each day, for six days, was observed on activity of some of the anti-oxidant enzymes and levels of malondialdehyde (as an index of free radical mediated damage) in the platelets of patients reperfused after myocardial infarction. It has been found that vitamin E administration significantly lowers the level of malondialdehyde in the patients. Vitamin E administration increases the activities of anti oxidant enzymes (viz. superoxide dismutase, glutathione reductase and catalase) tested both in the patients and healthy controls. Vitamin E administration causes general stimulation of anti-oxidant enzyme activities both in healthy persons and the patients, however, lowering of lipid per-oxidation upon administration of vitamin E is specific for patients. These findings exhibit beneficial role of vitamin E administration in the management of the patients reperfused after myocardial infarction.

Effect of vitamin E on the platelet xanthine oxidase and lipid peroxidation in the patients of myocardial infarction.

Platelets play important role in precipitating ischaemic myocardial syndromes in many ways. One of the consequences of ischaemic diseases is excessive generation of oxygen derived free radicals that have numerous pathophysiological consequences. Platelet pro-oxidant enzyme, xanthine oxidase is one of the sources of generation of free radicals. In the present paper, we report the effect of administration of vitamin E along with aspirin on the levels of platelet xanthine oxidase and extent of free radical mediated damage in the patients reperfused after myocardial infarction.Our findings show that administration of 400 mg. vitamin E for six days along with 80 mg. aspirin has an excellent anti-oxidant effect as evidenced by reduced platelet xanthine oxidase activity and lowering of malondialdehdye (MDA) levels which is an index of the extent of free radical mediated damage.

Effect of phytohormones on pectate lyase activity in ripening Musa acuminata.

A differential activity peak of pectate lyase (PEL) was observed during ripening of banana fruits (Musa acuminata Harichhal) receiving different hormone treatments. Exposure of fruits to 25 ppm ethylene for 24 h, as well as dipping of M. acuminata fruits in 1 mM 2,4-dichlorophenoxy acetic acid (2,4-D) for 4 h, hastened fruit ripening. Both PEL activity peak and climacteric peak were observed on the 4th and 10th days of treatment with ethylene and 2,4-D, respectively, compared to the 16th day in control fruits. Gibberellic acid (GA) treatment retarded fruit ripening and both PEL activity and climacteric peaks were observed on the 19th day. Treatment of fruits with ethylene or 2,4-D also advanced the appearance of a polygalacturonase (PG) peak and GA delayed its appearance, but the activity peaks always appeared in post-climacteric fruits, in contrast to PEL activity peaks coinciding with the respiratory peaks.

Blue light-sensitive plasma membrane bound exogenous NADH oxidase in Cuscuta reflexa.

Protoplasts isolated from Cuscuta reflexa exhibited a higher rate of exogenous NADH oxidation as compared to NADPH in the dark. NAD(P)H oxidation was monitored by measuring the rate of oxygen consumption and this oxidase system was sensitive to blue light. Both NADH oxidase and its blue light sensitivity were inhibited by -SH group reacting agents. The corresponding changes occurring in H+-extrusion activity and intracellular ATP levels were also monitored. Stimulation of NADH oxidation under blue light corresponded to increased rate of H+-extrusion and intracellular ATP level, the converse was also true under NADH oxidase inhibitory conditions. These observations suggested a close functional association between blue light-sensitive plasma membrane bound redox activity and H+-ATPase in this tissue. Further, concanavalin A binding of protoplasts resulted in a loss in NADH oxidase activity and its blue light sensitivity suggesting apoplastic location and glycoprotein nature of the blue light sensitive NADH oxidase system in Cuscuta.

Transplasma membrane electron transport in plants.

The presence of transplasma membrane electron transport in a variety of plant cells and tissues is reported. It is now agreed that this property of eukaryotic cells is of ubiquitous nature. Studies with highly purified plasma membranes have established the presence of electron transport enzymes. Two types of activities have been identified. One, termed "Standard" reductase, is of general occurrence. The other, inducible under iron deficiency and relatively more active, is "Turbo" reductase. However, the true nature of components participating in electron transport and their organization in the plasma membrane is not known. The electron transport is associated with proton release and uses intracellular NAD(P)H as substrate. The electron flow leads to changes in intracellular redox status, pH, and metabolic energy. The responsiveness of this system to growth hormones is also observed. These findings suggest a role for electron flow across the plasma membrane in cell growth and regulation of ion transport. Involvement of this system in many other cellular functions is also argued.

Changes in intracellular redox and energy status during induced transplasma membrane electron transport in Cuscuta protoplasts.

Extracellular reduction of ferricyanide was exhibited by isolated Cuscuta protoplasts. A larger decrease in NADH than NADPH levels of the ferricyanide-treated protoplasts pointed to the major involvement of the former as an electron donor. Glutathione levels were also found to be lowered in similarly treated tissue. The time-dependent variation in intracellular ATP levels in presence of ferricyanide supported the concept of plasma membrane ATPase activation during transplasma membrane electron transport in eukaryotes.

A link between transport and plasma membrane redox system(s) in carrot cells.

Carrot (Daucus carota L.) cells grown in suspension culture oxidized exogeneous NADH. The NADH oxidation was able to stimulate K+ (86Rb+) transport into cells, but it did not affect sucrose transport. N,N'-Dicyclohexyl-carbodiimide, diethylstilbestrol, and oligomycin, which only partially inhibited NADH oxidation, almost completely collapsed the K+ (86Rb+) transport. Vanadate, which is less effective as an ion transport inhibitor, was less effective in inhibiting the NADH-driven transport of K+ (86Rb+). p-Fluormethoxycarbonylcyanide phenylhydrazone inhibits the K+ transport over 90% including that induced by NADH. The results are interpreted as evidence that a plasma membrane redox system in root cells is closely associated with the ATPase which can drive K+ transport. Because of the inhibitor effects, it appears that membrane components common to the redox system and ATPase function in the transport of K+.

Effect of endosulfan on plasma membrane function of the yeast Rhodotorula gracilis.

The effects of endosulfan on Rhodotorula gracilis cells are varied and concentration-dependent. They are exhibited as increased rate of respiration, retardation in pH-recovering activity of cell suspensions and loss in the rate or D-xylose uptake. The temperature dependence of sugar uptake indicated that endosulfan reacts with some membrane component(s).

Evidence for a proton/sugar symport in the yeast Rhodotorula gracilis (glutinis).

1. The uptake of monosaccharides and polyols in the obligatory aerobic yeast Rhodotorula gracilis (glutinis) was accompanied by proton uptake. 2. The half-saturation constant of transport, KT, depended on pH, changing from about 2mM at pH 4.5 to 80mM at pH8.5 for D-xylose; this change of the effective carrier affinity was reversible. 3. The apparent dissociation constant of the monosaccharide carrier was estimated at pKa 6.75. 4. At pH8.5, when the pH gradient across the cell membrane vanished, no sugar accumulation was demonstrable. 5. The half-saturation constants of sugar uptake and H+ co-transport were very similar to each other, the latter obviously being controlled by the former. 6. The H+/sugar stoicheiometry remained constant under various physiological conditions; it amounted to one H+ ion per sugar molecule taken up. 7. The data are interpreted as a strong piece of evidence in favour of the active monosaccharide transport in R. gracilis (glutinis) being an H+-symport energized by the electrochemical gradient of H+ across the plasma membrane of the yeast.

"Lithium non-responders" in a lithium clinic.

The present study is concerned with the outcome of long-term lithium maintenance therapy administered to 107 manic-depressive patients after more than 12 months. Nine patients failed to respond despite having met the criteria for maintenance within the therapeutic range of lithium. This group, termed "lithium non-responders", had all shown bipolar illness with gross morbidity with frequent cycles, greater than 4 per year, seven had a family history of affective illness (six bipolar). The study did not demonstarte any other clear factors common to the "non-responders" group.

Encephalitis presenting as acute schizophrenia.

Three patients developed symptoms suggestive of acute schizophrenia. In each case there were no abnormal neurological findings on admission to hospital. Within a few days clinical evidence of encephalitis became apparent, and appropriate treatment was given. Only one patient made a full recovery.