Investigation of central mechanism of insulin induced hypoglycemic convulsions in mice

Insulin produces seizures in healthy and diabetic animals. Amongst suggested mechanisms, the role of neuromodulators and neurotransmitters is not clear. The present study explores the mechanisms involved in insulin-induced convulsions. Convulsions were induced in Swiss male albino mice with graded doses of insulin. Blood sugar levels were measured prior to and after the first convulsion. Drugs like 5-HTP (5-HT precursor), pCPA (5-HT depletor), ondansetron (5-HT3 antagonist), ketanserin (5-HT, antagonist), ketamine (NMDA antagonist), 1-dopa (dopamine precursor) and reserpine (amine depletor) were studied for interaction with convulsive behaviour induced by insulin. Insulin in 2 IU/kg dose did not produce convulsions while 4 and 8 IU/kg doses produced convulsions in 50% and 100% of animals respectively. 5-HTP, ondansetron, ketanserin, ketamine and l-dopa significantly protected/inhibited animals from convulsions at all studied doses of insulin. On the contrary, pCPA and reserpine potentiated insulin induced convulsions. Insulin caused mortality in 40 and 100% animals with 4 and 8 IU/kg doses respectively. pCPA and reserpine treatments caused mortality at all doses of insulin, while other drugs did not influence insulin induced mortality. Blood sugar levels were reduced in all groups irrespective of the presence or absence of convulsions. A definitive link of serotonergic, dopaminergic and excitatory amino acid pathways in mediating insulin-induced hypoglycemic convulsions is suggested.     

Alterations in rat mineral metabolism induced by acute ammonium acetate infusion

1. Acute ammonium intoxication in rat was produced by an i.v. overload of 1000 nmoles of ammonium acetate infunded during 15 min. 2. The load of ammonium produced sodium and potassium accumulation in muscle and plasma, minor in liver, and decreased these metal levels in kidney. 3. Blood and muscle magnesium content was strongly altered as a result of ammonium intoxication. 4. Calcium plasma levels, iron blood levels and iron hepatic stock diminished after the ammonium infusion. 5. Copper and zinc homeostasis were insignificantly altered.     

Carbohydrate metabolism in Bifidobacteria

Members of the genus Bifidobacterium can be found as components of the gastrointestinal microbiota, and are believed to play an important role in maintaining and promoting human health by eliciting a number of beneficial properties. Bifidobacteria can utilize a diverse range of dietary carbohydrates that escape degradation in the upper parts of the intestine, many of which are plant-derived oligo- and polysaccharides. The gene content of a bifidobacterial genome reflects this apparent metabolic adaptation to a complex carbohydrate-rich gastrointestinal tract environment as it encodes a large number of predicted carbohydrate-modifying enzymes. Different bifidobacterial strains may possess different carbohydrate utilizing abilities, as established by a number of studies reviewed here. Carbohydrate-degrading activities described for bifidobacteria and their relevance to the deliberate enhancement of number and/or activity of bifidobacteria in the gut are also discussed in this review.     

Carbohydrate metabolism in Agrobacterium tumefaciens

The activity of pentose cycling (PC) reactions in Agrobacterium tumefaciens is much greater than that normally found in bacteria, and in this regard the organism represents a unique category. Equations specifically derived from radiorespirometric data for bacteria with high PC activity in the presence of an alternate pathway are presented. A. tumefaciens utilizes d-glucose by strictly aerobic mechanisms involving the Entner-Doudoroff (ED) and PC pathways; relative participation by the ED pathway is 55% and by the PC cycle, 44%. The 3-ketoglycose-synthesizing system in the bacterium does not affect the relative participation of these two pathways. Radiorespirometric and enzymatic analyses clearly demonstrate that the Embden-Meyerhof-Parnas pathway does not function. Studies on the oxidation of pyruvic, acetic, succinic, and glutamic acids show that terminal respiration includes both the tricarboxylic acid and glyoxylic acid cycles.