Vitamin E prevents deleterious effects of di (2-ethyl hexyl) phthalate, a plasticizer used in PVC blood storage bags.

Vitamin E administration prevented DEHP induced deleterious effects like (i) degenerative changes in the brain and thyroid, (ii) decrease in the activity of neuronal membrane Na+ - K+ ATPase, (iii) decrease in the concentration of insulin, cortisol and TSH, and (iv) the increase in T3 and T4 in female Albino rats. The results suggest use of vitamin E to prevent harmful effects of repeated transfusion of DEHP containing blood as in thalassemia patient. The possibility of using vitamin E to prevent the harmful effects of repeated transfusion of DEHP containing blood, as in thalassemia patients, is discussed.

Changes in some hormones by low doses of di (2-ethyl hexyl) phthalate (DEHP), a commonly used plasticizer in PVC blood storage bags & medical tubing.

BACKGROUND & OBJECTIVES: Di (2-ethyl hexyl) phthalate (DEHP), a plasticizer commonly used in PVC blood storage bags leaches out in significant amounts into blood during storage. In view of many reports on the toxicity of this compound, it was considered necessary to investigate the effect of DEHP at the low level solubilized in blood on some important hormones in rats and in human blood stored in DEHP plasticized blood bags. METHODS: Rats were administered DEHP at a low level of 750 microg/100 g body weight on alternate days for 14 days. Changes in the serum insulin, blood glucose, liver glycogen level and T3, T4 and thyroid stimulating hormone (TSH) as well as cortisol in the serum were studied. Changes in the hormones were also studied in blood stored in DEHP plasticized PVC bags. RESULTS: The results indicated decrease in serum insulin, cortisol and liver glycogen, and increase in blood glucose, serum T3 and T4 in rats receiving DEHP. These changes were reversed when administration of DEHP was stopped. Similar changes in hormones were also observed in the blood stored in DEHP plasticized blood bags. INTERPRETATION & CONCLUSION: The results indicated that administration of DEHP at low levels to rats caused symptoms of diabetes, thyroid and adrenocortical dysfunction. Though the results obtained in rats cannnot be extrapolated to human, the fact that similar hormonal changes seen in human blood stored in DEHP plasticized blood bags may suggest possibility of DEHP causing similar changes in human. The fact that these changes were reversed in rats when DEHP administration was stopped, indicates that transfusion of a few units of blood to a recipient may not be harmful, but it may pose a problem during repeated transfusions such as in thalassaemia patients.

Inhibition of membrane Na(+)-K+ Atpase of the brain, liver and RBC in rats administered di(2-ethyl hexyl) phthalate (DEHP) a plasticizer used in polyvinyl chloride (PVC) blood storage bags.

Significant amounts of di(2-ethylhexyl) phthalate (DEHP) leach out into blood stored in DEHP plasticized polyvinyl chloride (PVC) bags resulting in the exposure of recipients of blood transfusion to this compound. The aim of this study was to find out whether DEHP at these low levels has any effect on the activity of membrane Na(+)-K+ ATPase, since a decrease in this enzyme activity has been reported to take place in a number of disorders like neurodegenerative and psychiatric disorders, coronary artery disease and stroke, syndrome-X, tumours etc. DEHP was administered (ip) at a low dose of 750 microg/100 g body weight to rats and the activity of membrane Na(+)-K+ ATPase in liver, brain and RBC was estimated. Histopathology of brain, activity of HMG CoA reductase (a major rate limiting enzyme in the isoprenoid pathway of which digoxin, the physiological inhibitor of Na(+)-K+ ATPase is a product), intracellular concentration of Ca2+ and Mg2+ in RBC (which is altered as a result of inhibition of Na(+)-K+ ATPase) were also studied. (In the light of the observation of increase of intracellular Ca2+ load and intracellular depletion of Mg2+ when Na(+)-K+ ATPase is inhibited). Histopathology of brain revealed areas of degeneration in the rats administered DEHP. There was significant inhibition of membrane Na(+)-K+ ATPase in brain, liver and RBC. Intracellular Ca2+ increased in the RBC while intracellular Mg2+ decreased. However activity of hepatic HMG CoA reductase decreased. Activity of Na(+)-K+ ATPase and HMG CoA reductase, however returned to normal levels within 7 days of stopping administration of DEHP. The inhibition of membrane Na(+)-K+ ATPase activity by DEHP may indicate the possibility of predisposing recipients of transfusion of blood or hemodialysis to the various disorders mentioned above. However since this effect is reversed when DEHP administration is stopped, it may not be a serious problem in the case of a few transfusion; but in patients receiving repeated blood transfusion as in thalassemia patients or patients undergoing hemodialysis, possibility of this risk has to be considered. This inhibition is a direct effect of DEHP or its metabolites, since activity of HMG CoA reductase, (an enzyme which catalyses a major rate limiting step in the isoprenoid pathway by which digoxin, the physiological inhibitor of Na(+)-K+ ATPase is synthesized) showed a decrease.

Changes in the isoprenoid pathway with transcendental meditation and Reiki healing practices in seizure disorder.

A quantal perceptive model of brain function has been postulated by several groups. Reiki-like healing practices in seizure disorder (ILAE classification-II E-generalized seizures-tonic clonic), involving transfer of life force or low level of electromagnetic force (EMF) from the healer to the recipient patient, may act via quantal perceptive mechanisms. Increased synthesis of an endogenous membrane Na+-K+ ATPase inhibitor digoxin and a related tyrosine / tryptophan transport defect has been demonstrated in refractory seizure disorder (ILAE classification-II E-generalized seizures-tonic clonic). Reiki-like healing practices in refractory epilepsy results in a reduction in seizure frequency. Reiki-like healing practices produce membrane stabilization and stimulation of membrane Na+-K+ ATPase activity by quantal perception of low levels of EMF. The consequent intracellular hypermagnesemia inhibits HMG CoA reductase activity and digoxin synthesis resulting in the alteration of the neutral amino acid transport (tryptophan / tyrosine) defect. A hypothalamic digoxin-mediated quantal perception model of brain function is proposed. The phenomena of biological transmutation and consequent hypermagnesemia occurring in the resultant neuronal quantal state is also discussed.

Hypothalamic digoxin and regulation of body mass index.

The hypothalamus produces digoxin, an endogenous membrane Na+-K+ ATPase inhibitor and regulator of neurotransmission. Digoxin being a steroidal glycoside, is synthesised by the isoprenoid pathway. In view of the reports of elevated digoxin levels in metabolic syndrome X with high body mass index, the isoprenoid pathway mediated biochemical cascade was assessed in individuals with high and low body mass index. It was also assessed in individuals with differing hemispheric dominance to find out the relationship between digoxin status, body mass index and hemispheric dominance. The isoprenoid pathway metabolites, tryptophan / tyrosine catabolic patterns and membrane composition were assessed. In individuals with high body mass index an upregulated isoprenoid pathway with increased HMG CoA reductase activity, serum digoxin and dolichol levels and low ubiquinone levels were observed. The RBC membrane Na+-K+ ATPase activity and serum magnesium levels were decreased. The tyrosine catabolites (dopamine, morphine, epinephrine and norepinephrine) were reduced and the tryptophan catabolites (serotonin, quinolinic acid, strychnine and nicotine) were increased. There was an increase in membrane cholesterol : phospholipid ratio and a reduction in membrane glycoconjugates in individuals with high body mass index. The reverse patterns were seen in individuals with low body mass index. The patterns in individuals with high body mass index and low body mass index correlated with right hemispheric dominance and left hemispheric dominance respectively. Hemispheric dominance and digoxin status regulates the differential metabolic pattern observed in individuals with high and low body mass index.

Familial hypodigoxinemic membrane Na(+)-K(+) ATPase upregulatory syndrome - relation between digoxin status and cerebral dominance.

A family with coexistence of hypotension, recurrent respiratory infection, motor tics, obsessive compulsive disorder, major depressive disorder, early onset osteoporosis, low body mass index, bulimia nervosa and healthy aging with longevity is described. The family members had hyposexual behavior, less tendency for spirituality, had no insomnia but a tendency towards increased somnolence, no addictive behaviour, had more bonding and affectionate behavior and were less creative with an average IQ. There was no vascular thrombosis, systemic neoplasm and neuronal degeneration in the index family. All members of the family were left hemispheric dominant. The level of serum digoxin, HMG CoA reductase activity and dolichol was found to be decreased in all with a corresponding increase in RBC Na(+)-K(+) ATPase activity and serum ubiquinone magnesium level. There was increase in tyrosine catabolites and a reduction in tryptophan catabolites in serum. Total and individual glycosaminoglycan fractions, carbohydrate residues of glycoproteins, glycolipids, activity of GAG degrading enzymes and glycohydrolases were decreased in serum. The concentration of RBC membrane total GAG and carbohydrate residues of glycoproteins increased while cholesterol : phospholipid ratio of membrane decreased. The activity of free radical scavenging enzymes were increased while the concentration of free radicals decreased significantly. The same biochemical patterns were observed in left hemispheric dominance as opposed to right hemispheric dominance. The significance of these findings in the pathogenesis of these disorders is discussed.

Endogenous sodium-potassium ATPase inhibition related biochemical cascade in trisomy 21 and Huntington's disease: neural regulation of genomic function.

The isoprenoid pathway related cascade was assessed in trisomy 21 and Huntington's disease. Membrane Na+-K+ ATPase activity, serum magnesium and ubiquinone were decreased while HMG CoA reductase activity, serum digoxin and dolichol levels were increased in both the disorders. There were increased levels of tryptophan catabolites (nicotine, strychnine, quinolinic acid and serotonin) and decreased levels of tyrosine catabolites (dopamine, noradrenaline and morphine) in both trisomy 21 and Huntington's disease. There was an increase in dolichol levels, carbohydrate residues of glycoproteins, glycolipids, total/individual GAG fractions and lysosomal enzymes in both disorders. Reduced levels of ubiquinone, reduced glutathione and free radical scavenging enzymes as well as increased lipid peroxidation products and nitric oxide were noticed in both the disorders. The role of hypothalamic digoxin and a disordered isoprenoid pathway in the pathogenesis of trisomy 21 and Huntington's disease is discussed.

Inhibition of membrane Na+-K+ ATPase activity: a common pathway in central nervous system disorders.

OBJECTIVES: The study was conducted to assess the role of hypothalamic digoxin in neuropsychiatric and systemic disorders. A hypothesis regarding the central role of hypothalamic digoxin in neuroimmunoendocrine integration is proposed. METHODOLOGY: Blood samples from patients of CNS glioma, multiple sclerosis, systemic lupus erythematosis, subacute sclerosing panencephalitis, primary generalized epilepsy, Parkinson's disease, Down syndrome, AIDS dementia with neuropsychiatric features, syndrome X with multiple lacunar state, senile dementia, familial group (a family with familial coexistence of schizophrenia, Parkinson's disease, primary generalized epilepsy, malignant neoplasia, rheumatoid arthritis and syndrome X over three generations), schizophrenia and manic depressive psychosis were analysed for RBC membrane Na+-K+ ATPase, levels of digoxin and Mg++. RESULTS: Inhibition of RBC membrane Na+-K+ ATPase activity was observed in most cases along with increase in the levels of serum digoxin and decrease in the level of serum Mg++. CONCLUSION: The decreased Na+-K+ ATPase activity can be due to increased digoxin, which is a potent inhibitor of this enzyme. The inhibition of Na+-K+ ATPase can contribute to increase in intracellular calcium and decrease in magnesium, which can result in 1) defective neurotransmitter transport mechanism, 2) neuronal degeneration and apoptosis, 3) mitochondrial dysfunction, 4) defective golgi body function and protein processing dysfunction, 5) immune dysfunction and oncogenesis. The mechanism of how increased intracellular calcium and decreased magnesium can contribute to the above effects is discussed.

Changes in the isoprenoid pathway in syndrome X.

This study assessed the changes in digoxin and some other metabolites of the isoprenoid pathway in metabolic syndrome X presenting with multiple lacunar state. There was an increase in plasma HMG CoA reductase activity with a consequent increase in serum digoxin, which caused a reduction in RBC membrane Na+-K+ ATPase activity. There was an increase in serum tryptophan and its metabolites and a decrease in tyrosine and its metabolites. Serum magnesium was decreased with consequent alteration in the metabolism of glycosaminoglycans and glycolipids. Increase in dolichol, another product of the isoprenoid pathway resulted in alteration in glycoprotein metabolism. Changes in the composition of membrane glycosaminoglycans, glycoproteins and cholesterol:phospholipid ratio were also observed in this disorder leading to decreased lysosomal stability. Decrease in ubiquinone, another isoprenoid metabolite resulted in alteration in the free radical generation. Membrane Na+-K+ ATPase inhibition due to digoxin, altered membrane structure, increased tryptophan catabolites and decreased tyrosine catabolites can lead on to increased intracellular calcium and reduced intracellular magnesium which can account for the symptoms of syndrome X.

Endogenous sodium potassium ATPase inhibition related biochemical cascade and the acquired immunodeficiency syndrome--neural regulation of viral replication and immune response to the virus.

The isoprenoid pathway and its metabolites - digoxin, dolichol and ubiquinone were assessed in acquired immunodeficiency syndrome. Digoxin is an endogenous regulator of membrane Na+-K+ ATPase secreted by the human hypothalamus. The HMG CoA reductase activity was increased with increased digoxin and dolichol levels and reduced ubiquinone levels in AIDS. Membrane Na+-K+ ATPase activity and serum magnesium levels were reduced. The tryptophan catabolites were increased and the tyrosine catabolites were reduced. The glycoconjugate metabolites were increased and lysosomal stability was reduced. There was reduced incorporation of glycoconjugates into membranes and increased membrane cholesterol: phospholipid ratio. Lipid peroxidation products and NO were increased while free radical scavenging enzymes and reduced glutathione were reduced. The role of the isoprenoid pathway related cascade in the pathogenesis of AIDS is discussed.

Serum and tissue glycoconjugates, digoxin and magnesium levels in chronic calcific pancreatitis.

BACKGROUND: Endogenous or exogenous digoxin can lead to membrane Na+,K+-ATPase inhibition and hypomagnesemia. Low magnesium levels can lead to increased glycosaminoglycans (GAG) concentration in many organs. Aim: To measure the serum levels of pancreatic GAG and glycoproteins, two major components of the extracellular matrix, in patients with chronic calcific pancreatitis (CCP). Serum levels of magnesium and digoxin were also assessed. METHODS: Patients with CCP and age- and sex-matched healthy control subjects (15 each) were studied. Serum GAG, Mg and digoxin levels were measured. RBC membrane Na+,K+-ATPase activity was also assessed. Pancreatic tissue obtained at autopsy from seven patients with CCP and sex- and age-matched healthy subjects who had died in accidents were also tested for GAG and glycoproteins. RESULTS: Total GAG levels were significantly increased in the serum and pancreas of patients with CCP. This was associated with lower serum Mg levels, increased serum digoxin levels and decreased RBC membrane Na+,K+-ATPase activity. CONCLUSION: Exogenous or endogenous digoxin-induced hypomagnesemia and the consequent altered glycoconjugate metabolism may be important in the pathogenesis of CCP.

Hypothalamic digoxin and irritable bowel syndrome.

BACKGROUND: The hypothalamus produces an endogenous membrane Na+-K+ ATPase inhibitor digoxin that can modulate neurotransmitter transport and may play a role in hemispheric dominance. It can also modulate glycoconjugate synthesis and thus affect synaptic connectivity in the bowel wall. Digoxin could play a role in the genesis of irritable bowel syndrome (IBS). AIM: To study digoxin status in IBS and to correlate it with hemispheric dominance. METHODS: The isoprenoid pathway, tryptophan/tyrosine catabolic patterns and glycoconjugate metabolism were assessed in patients with IBS and in right hemispheric dominant/left hemispheric dominant/bihemispheric dominant individuals. RESULTS: The isoprenoid pathway was upregulated in IBS, with increased HMG CoA reductase activity (0.8 [0.07] vs 0.4 [0.06] in controls; p<0.01), serum digoxin (14.8 [1.0] vs 29.0 [1.2] ng/dL; p<0.01) and dolichol levels (63.8 [3.0] vs 120.3 [3.6] mg/dL; p<0.01). RBC membrane Na+-K+ ATPase activity (3.0 [0.2] vs 1.0 [0.1] microg/p/mg protein; p<0.01), serum magnesium (1.7 [0.1] vs 1.0 [0.1] mg/dL; p<0.01) and ubiquinone (86.4 [5.9] vs 39.8 [1.2] microg/dL; p<0.01) were reduced. There was increase in tryptophan catabolites and reduction in tyrosine catabolites. Serum total glycosaminoglycan and carbohydrate component of glycoproteins were increased in IBS. The activity of glycosaminoglycan degrading enzymes and glycohydrolases were increased. This pattern correlated with those obtained in right hemispheric chemical dominance. CONCLUSION: Hypothalamic digoxin and right hemispheric dominance could play a role in the genesis of irritable bowel syndrome.

Membrane Na+ K+ ATPase inhibition related dyslipidemia and insulin resistance in neuropsychiatric disorders.

There are several reports in literature implicating cholesterol metabolism in the pathogenesis of neuronal degenerations, oncogenesis, functional neuropsychiatric disorders and multiple sclerosis. Biosynthesis of cholesterol takes place by the isoprenoid pathway, which also produces digoxin, an inhibitor of membrane Na(+)-K+ ATPase. Inhibition of this enzyme results in intracellular Mg++ deficiency which can influence cholesterol metabolism. Digoxin also influences transport of tryptophan and tyrosine which are precursors of various neurotransmitters. Alterations in digoxin, membrane Na(+)-K+ ATPase and also in neurotransmitters have been reported in the disorders mentioned above. In view of this, serum lipid profile, activity of plasma HMG CoA reductase (the major rate limiting step in the isoprenoid pathway), RBC membrane Na(+)-K+ ATPase activity, serum Mg++ concentration, concentration of digoxin and concentration of serum neurotransmitters were studied in some neuropsychiatric disorders. The serum serotonin level was increased while that of serum dopamine and noradrenaline was reduced. Serum digoxin levels were high and RBC membrane sodium-potasium ATPase activity and serum magnesium were reduced. There was a reduction in HDL cholesterol and increase in plasma triglycerides (pattern similar to insulin resistance and syndrome X) in most of the disorders studied. The HMG CoA reductase activity was high, the serum total cholesterol was increased while RBC membrane cholesterol was reduced in most of the cases. The significance of increased digoxin with consequent inhibition of membrane Na(+)-K+ ATPase in relation to changes in cholesterol metabolism and insulin resistance type of dyslipidemia is discussed in this paper.

Studies on digoxin--14C-acetate incorporation in to digoxin and degenerative changes in the brain in rats administered digoxin.

The human hypothalamus produces an endogenous membrane Na+-K+ ATPase inhibitor digoxin. Digoxin is a steroidal glycoside and could be synthesised by the isoprenoid pathway. The other metabolites of the isoprenoid pathway are cholesterol, dolichol and ubiquinone. We have tried to find out the extent of incorporation of 14C acetate into digoxin in rat brain. The effects of digoxin administration on the rat brain was also studied. The results show that the percentage incorporation of 14C acetate into digoxin is low but detectable. The maximum incorporation was observed for cholesterol, followed by dolichol and finally ubiquinone. The histopathological changes observed after digoxin administration were focal degeneration of the ganglion cells in the cerebrum and cerebellum. The carbohydrate components of the glycoproteins were reduced and the concentration of serotonin, dopamine, and epinephrine showed a significant increase. The role of digoxin in mediating neuronal cell death is discussed.

The isoprenoid pathway in lone atrial fibrillation with embolic stroke.

BACKGROUND: The isoprenoid pathway was assessed and compared in patients of lone atrial fibrillation with embolic stroke as well as in patients with right hemispheric, left hemispheric and bihemispheric dominance to determine the role of hemispheric dominance in its pathogenesis. METHODS AND RESULTS: The activities of hydroxyl methyl glutaryl-CoA reductase and RBC sodium-potasium ATPase as well as serum levels of plasma magnesium, digoxin, dolichol and ubiquinone were measured. The tyrosine/tryptophan catabolic patterns, glycoconjugate metabolism, free radical metabolism and RBC membrane composition were also assessed. In patients with lone atrial fibrillation with embolic stroke, there was elevated digoxin synthesis, increased dolichol and glycoconjugate levels, and low ubiquinone and elevated free radical levels. There was also an increase in tryptophan catabolites and a reduction in tyrosine catabolites: and an increase in the cholesterol: phospholipid ratio with a reduction in the glycoconjugate levels of the RBC membrane. The same biochemical patterns were obtained in individuals with right hemispheric dominance whereas the patterns were reversed in patients with left hemispheric dominance. CONCLUSIONS: Lone atrial fibrillation with embolic stroke is associated with an upregulated isoprenoid pathway and elevated digoxin secretion from the hypothalamus. This occurs in right hemisphere-dominant individuals.

Tryptophan and tyrosine catabolic pattern in neuropsychiatric disorders.

Catabolism of tryptophan and tyrosine in relation to the isoprenoid pathway was studied in neurological and psychiatric disorders. The concentration of trytophan, quinolinic acid, kynurenic acid, serotonin and 5-hydroxyindoleacetic acid was found to be higher in the plasma of patients with all these disorders; while that of tyrosine, dopamine, epinephrine and norepinephrine was lower. There was increase in free fatty acids and decrease in albumin (factors modulating tryptophan transport) in the plasma of these patients. Concentration of digoxin, a modulator of amino acid transport, and the activity of HMG CoA reductase, which synthesizes digoxin, were higher in these patients; while RBC membrane Na+-K+ ATPase activity showed a decrease. Concentration of plasma ubiquinone (part of which is synthesised from tyrosine) and magnesium was also lower in these patients. No morphine could be detected in the plasma of these patients except in MS. On the other hand, strychnine and nicotine were detectable. These results indicate hypercatabolism of tryptophan and hypocatabolism of tyrosine in these disorders, which could be a consequence of the modulating effect of hypothalamic digoxin on amino acid transport.

Hypothalamic digoxin and neural regulation of blood pressure and vascular thrombosis.

The isoprenoid pathway produces three key metabolites--digoxin (membrane sodium-potassium ATPase inhibitor and regulator of neurotransmitter/aminoacid transport), dolichol (regulates N-glycosylation of proteins) and ubiquinone (free radical scavenger). This was assessed in patients with essential hypertension, familial hypotension, acute coronary artery disease and acute thrombotic strokes. The pathway was also assessed in patients with right hemispheric, left hemispheric and bihemispheric dominance for comparison. In patients with acute coronary artery disease, acute thrombotic stroke, essential hypertension and right hemispheric dominance, there was elevated digoxin synthesis, increased dolichol and glycoconjugate levels and low ubiquinone and high free radical levels. There was also an increase in tryptophan catabolites, reduction in tyrosine catabolites, increase in cholesterol-phospholipid ratio and a reduction in glycoconjugate level of RBC membrane in this group of patients as well as in those with right hemispheric dominance. In patients with familial hypotension and left hemispheric dominance, the patterns were reversed. The role of a dysfunctional isoprenoid pathway and endogenous digoxin in the pathogenesis of essential hypertension and familial hypotension and in thrombotic vascular disease in relation to hemispheric dominance is discussed.

Endogenous strychnine, nicotine, and morphine--description of hypo and hyper-strychninergic, nicotinergic and morphinergic state in relation to neuropsychiatric diseases.

Previous work from this laboratory had demonstrated the presence of endogenous morphine, strychnine and nicotine in the mammalian brain and human serum samples. Morphine is synthesised from tyrosine and strychnine and nicotine from tryptophan. This study examines the role of strychnine, nicotine and morphine in neuropsychiatric disorders. The blood levels of tyrosine, tryptophan, strychnine, nicotine and morphine were studied as also RBC membrane Na(+)-K+ ATPase activity. It was found that serum tyrosine levels were reduced and tryptophan levels elevated in all neuropsychiatric disorders studied with a reduction in RBC Na(+)-K+ ATPase activity. Nicotine was present in significant amounts in serum of patients with schizophrenia, CNS glioma and syndrome X with multiple lacunar state. Morphine was present in significant amounts only in the serum of patients with multiple sclerosis and MDP. Strychnine was present in significant amounts in the serum of patients with epilepsy, Parkinson's disease and MDP. The presence of nicotine and strychnine in significant amounts could be related to elevated tryptophan levels suggesting the synthesis of these alkaloids from tryptophan. Morphine was not detected in most of the disorders owing to low tyrosine levels noted in them. Na(+)-K+ ATPase inhibition noticed in most of the disorders could be related to decreased hyperpolarising morphinergic transmission and increased depolarising nicotinergic and strychinergic transmission. The role of morphine, strychnine and nicotine in the pathogenesis of these disorders in the setting of membrane Na(+)-K+ ATPase inhibition is discussed.

Digoxin and membrane sodium potassium ATPase inhibition in cardiovascular disease.

Kerala has a high incidence of mucoid angiopathy, metabolic syndrome X and endomyocardial fibrosis. Magnesium deficiency has been reported in these disorders even though the Keralite diet has adequate magnesium. A possible cause of magnesium deficiency is the increased digoxin, a potent inhibitor membrane Na(+)-K+ ATPase which can lead to magnesium depletion. Digoxin is known to be synthesised by the hypothalamus and other tissues and can also be obtained from plant sources in the diet. Inhibition of Na(+)-K+ ATPase can cause intracellular magnesium depletion and increase in intracellular calcium. In view of these, a study has been carried out on the activity of membrane Na(+)-K+ ATPase, using RBC membrane, serum digoxin, magnesium and glycosaminoglycan levels in patients of mucoid angiopathy, endomyocardial fibrosis and syndrome X. Significant decrease in the membrane Na(+)-K+ ATPase was observed in patients while serum digoxin levels showed an increase. Serum magnesium was significantly lower while glycosaminoglycan levels were increased. The inhibition of Na(+)-K+ ATPase activity may be due to increase in endogenous and/or exogenous digoxin. This inhibition leads to depletion of intracellular magnesium and an increase in intracellular calcium load. The role of underlying magnesium-related insulin resistance and the consequence of this intracellular magnesium and calcium alteration in the pathogenesis of these disorders is discussed.

Isoprenoid pathway and free radical generation and damage in neuropsychiatric disorders.

Two substances which are products of the isoprenoid pathway, can participate in lipid peroxidation. One is digoxin, which by inhibiting membrane Na(+)-K+ ATPase, causes increase in intracellular Ca2+ and depletion of intracellular Mg2+, both effects contributing to increase in lipid peroxidation. Ubiquinone, another products of the pathway is a powerful membrane antioxidant and its deficiency can also result in defective electron transport and generation of reactive oxygen species. In view of this and also in the light of some preliminary reports on alteration in lipid peroxidation in neuropsychiatric disorders, a study was undertaken on the following aspects in some of these disorders (primary generalised epilepsy, schizophrenia, multiple sclerosis, Parkinson's disease and CNS glioma)--1) concentration of digoxin, ubiquinone, activity of HMG CoA reductase and RBC membrane Na(+)-K+ ATPase 2) activity of enzymes involved in free radical scavenging 3) parameters of lipid peroxidation and 4) antioxidant status. The result obtained indicates an increase in the concentration of digoxin and activity of HMG CoA reductase, decrease in ubiquinone levels and in the activity of membrane Na(+)-K+ ATPase. There is increased lipid peroxidation as evidenced from the increase in the concentration of MDA, conjugated dienes, hydroperoxides and NO with decreased antioxidant protection as indicated by decrease in ubiquinone, vit E and reduced glutathione in schizophrenia, Parkinson's disease and CNS glioma. The activity of enzymes involved in free radical scavenging like SOD, catalase, glutathione peroxidase and glutathione reductase is decreased in the above diseases. However, there is no evidence of any increase in lipid peroxidation in epilepsy or MS. The role of increased operation of the isoprenoid pathway as evidenced by alteration in the concentration of digoxin and ubiquinone in the generation of free radicals and protection against them in these disorders is discussed.