Urinary indican in healthy Indian subjects

Forty normal subjects have been taken for the present study. The mean Indican excretion was 40.45 mg/24 hrs. The mean jejunal count was 1.96 x 10(3) +/- 5.39 x 10(3) organisms/ml and 40% of the jejunal aspirates were sterile. Wide range of bacteria were cultured bu the coliform organisms were obtained in only 16.6%. There was a significant correlation between Indican excretion and total bacterial count (P less than .01).

Spectroscopy at very high pressures. 14: Laser Raman scattering in ultrasmall samples in a diamond anvil cell

The problem of obtaining Raman spectra at high pressures with a diamond anvil cell is analyzed, and the successful use of a 90 degrees off-axis ellipsoidal mirror for collection in both 0 degrees and 180 degrees scattering modes is demonstrated with nu(OH) spectra of ice VI, VII, and vIII.

Opiate-dependent modulation of adenylate cyclase

Reactions mediated by the opiate receptors that inhibit adenylate cyclase (EC 4.6.1.1) are closely coupled to subsequent reactions that gradually increase adenylate cyclase activity of neuroblastoma X glioma NG108-15 hybrid cells. Opiate-treated cells have higher basal-, prostaglandin E1-, and 2-chloroadenosine-stimulated activities than do control cells. However, NaF or guanosine 5'-(beta, gamma-imido)triphosphate abolishes most of the differences in adenylate cyclase activity observed with homogenates from control and opiate-treated cells. Cycloheximide blocked some, but not all, of the opiate-dependent increase in adenylate cyclase activity. These results suggest that the opiate-dependent increase in adenylate cyclase is due to conversion of adenylate cyclase to a form with altered activity. Protein synthesis also is required for part of the opiate effect. We propose that activity of adenylate cyclase determines the rate of conversion of the enzyme from one form to the other and that opiates, by inhibiting adenylate cyclase, alter the relative abundance of low- and high-activity forms of the enzyme.

The role of imipramine hydrochloride on plasma transaminase and glucose level on rats under altitude stress

The effect of exposure of albino rats to simulated high altitude stress of 5000 metres for 3 and 6 hrs on plasma transaminases, non-protein nitrogen (NPN), total protein percentages and blood sugar levels have been studied both with and without the administration of an anti-stress drug Imipramine HCl at 2.0 mg/kg body weight. The drug appears to have a slight hepatotoxic effect.

Dual regulation of adenylate cyclase accounts for narcotic dependence and tolerance

Narcotics affect adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] in two opposing ways, both mediated by the opiate receptor. The first process is the readily reversible inhibition of the enzyme by narcotics; the second is a compensatory increase in enzyme activity which is delayed in onset and relatively stable. Late positive regulation of the enzyme counteracts the inhibitory influence of morphine and is responsible for narcotic dependence and tolerance. The coupled inhibitory and positive regulatory mechanisms for adenylate cyclase provide a means of activating and deactivating neural circuits hours after the initial event and thus may play a role in a memory process.

Non-specific binding in the affinity chromatography of chymotrypsin

The strong and specific binding of chymotrypsin on chromatographic columns containing agarose substituted with N-sigma-amino caproyl-D-tryptophan methyl ester is abolished when the sigma-amino groups on the surface of the enzyme are reacted with acetic anhydride. Because the catalytic properties of the acetylated chymotrypsin are identical to those of the underivatized enzyme, it is concluded that the high affinity of chymotrypsin for this column is not due solely to biospecific inhibitor binding, which is by itself very weak, but requires reinforcement through weak non-specific interactions with the column support. It is postulated that these non-specific interactions include electrostatic interactions between agarose matrix and positively charged lysyl residues on the enzyme. The results demonstrate for the first time that residues on the surface of an enzyme not associated with its active site can play an important role in some chromatographic systems previously thought to be based on purely biospecific interactions.

Morphine receptors as regulators of adenylate cyclase activity

Morphine inhibits adenylate cyclase (EC 4.6.1.1) activity of neuroblastoma times glioma hybrid cells. The inhibition is stereospecific and is reversed by the antagonist, naloxone. The relative affinities of narcotics for the opiate receptor agree well with their effectiveness as inhibitors of adenylate cyclase. Morphine-sensitive and -insensitive cell lines were found, and the degree of sensitivity was shown to be dependent upon the abundance of narcotic receptors. Thus, morphine receptors are functionally coupled to adenylate cyclase. A molecular mechanism for narcotic addiction and tolerance is proposed.