Choline acetyltransferase activity of spinal cord cell cultures increased by co-culture with muscle and by muscle-conditioned medium

Activity of the enzyme choline acetyltransferase (CAT), which mediates the synthesis of the neurotransmitter, acetylcholine, was increased up to 20- fold in spinal cord (SC) cells grown in culture with muscle cells for 2 wk. This increase was directly related to the duration of co-culture as well as to the cell density of both the SC and muscle involved and was not affected by the presence of the acetylcholine receptor blocking agent, α-bungarotoxin. Glutamic acid decarboxylase (GAD) activity was often markedly decreased in SC-muscle cultures while the activities of acetylcholinesterase and several other enzymes were little changed. Increased CAT activity was also observed when SC cultures were maintained in medium which had been conditioned by muscle cells or by undifferentiated cells from embryonic muscle. Muscle-conditioned medium (CM) did not affect the activities of SC cell GAD or acetylcholinesterase. Dilution or concentration of the CM directly affected its ability to increase SC CAT activity , as did the duration and timing of exposure of the SC cells to the CM. The medium could be conditioned by muscle cells in the presence or absence of serum, and remained effective after dialysis or heating to 58 degrees C. Membrane filtration data were consistent with the conclusion that the active material(s) in CM had a molecular weight in excess of 50,000 daltons. We conclude that large molecular weight material that is released by muscle cells is capable of producing a specific increase in CAT activity of SC cells.     

Effect of α, β momorcharin on viability,caspase activity,cytochrome c release and on cytosolic calcium levels in different cancer cell lines

A multitude of plants have been used extensively for the treatment of cancers throughout the world. The protein, α, β momorcharin has been extracted from the plant Momordica charantia (MC), and it possesses anti-cancer and anti-HIV properties similar to the crude water and methanol soluble extract of the plant. This study investigated the anti-cancer effects and the cellular mechanisms of action of α, β momocharin (200–800 μM) on 1321N1, Gos-3, U87-MG, Sk Mel, Corl-23 and Weri Rb-1 cancer cell lines compared to normal healthy L6 muscle cell line measuring cell viability using MTT assay kit, Caspase-3 and 9 activities, cytochrome c release and intracellular free calcium concentrations [Ca²⁺]_i. The results show that α, β momorcharin can evoke significant dose-dependent (P < 0.05; Student’s t test) decreases in the viability (increases in cell death) of 1321N1, Gos-3, U87-MG, Sk Mel, Corl-23 and Weri Rb-1 cancer cell lines compared to healthy L6 muscle cell line and untreated glioma cells. α, β momorcharin (800 μM) also evoked significant (P < 0.05) increases in caspase-3 and 9 activities and cytochrome c release. Similarly, α, β momorcharin elicited significant (P < 0.05) time-dependent elevation in [Ca²⁺]_i in all five glioma cell lines compared to untreated cells. Together, the results have demonstrated that α, β momorcharin can exert its anti-cancer effect on different cancer cell lines by intracellular processes involving an insult to the mitochondria resulting in cellular calcium over loading, apoptosis, cytochrome release and subsequently, cell death.     

Dermal exposure to m-xylene leads to increasing oxidative species and low molecular weight DNA levels in rat skin.

Dermal absorption of organic solvents, such as m-xylene, can lead to skin inflammation and pathological changes within hours after exposure. This study detected oxidative species formation and low molecular weight (LMW) DNA in rat skin as potential indicators of m-xylene-induced skin injury. At 0, 1, 2, 4, and 6 h after the beginning of a 1-h exposure, skin samples were removed and analyzed for oxidative species formation and LMW DNA analysis. At 2 h, mean oxidative species levels increased significantly (P < 0.05) above unexposed samples. Significantly higher (P < 0.05) LMW DNA values were observed at 2, 4, and 6 h compared to unexposed controls. These results show that oxidative species formation and LMW DNA levels in the skin may serve as indicators for predicting safe exposure levels to m-xylene and other volatile organic solvents.     

A flavanone and a dihydrodibenzoxepin from Bauhinia variegata

Phytochemical analysis of the root bark of Bauhinia variegata Linn yielded a new flavanone, (2S)-5,7-dimethoxy-3',4'-methylenedioxyflavanone (1) and a new dihydrodibenzoxepin, 5,6-dihydro-1,7-dihydroxy-3,4-dimethoxy-2-methyldibenz [b,f]oxepin (2) together with three known flavonoids (3-5). The structures of the new compounds were determined on the basis of spectral studies.     

Role of prolactin on Leydig, Sertoli and germ cellular neutral lipids in bonnet monkeys, Macaca radiata.

To elucidate the specific influence of prolactin on neutral lipids in Leydig, Sertoli and germ cell compartments of the testis in immature and mature monkeys, the present study was carried out by injecting ovine prolactin (oPRL) (1 mg/kg body weight/twice daily for 10 days ip), to both age groups. Similarly, bromocryptine (an ergot alkaloid which inhibits prolactin secretion) was given to other sets of immature and mature monkeys (1 mg/kg body weight/twice daily for 10 days ip) to induce hypoprolactinemia. It was observed that after oPRL administration the total lipid accumulated in the germ cells of immature and mature monkeys. Total lipid was markedly decreased in the Leydig cells of mature monkeys only. But no such influence of PRL was evident in the Leydig cells of immature monkeys, suggesting an age-dependent effect of PRL on the Leydig cells. The increase in total lipid in the germ cells following PRL treatment was contributed by mono, di- and triacyl glycerols and free cholesterol. However, an opposite effect of PRL was evident in the Leydig cells of mature monkeys, where the cholesterols and glyceride fractions registered a decrease. The reduced cholesterol fractions in the Leydig cells following PRL treatment suggests the utilization of cholesterol for steroidogenesis. Sertoli cells were found to be comparatively resistant to change in PRL status. Bromocryptine treatment brought about the opposite effect of PRL in almost all parameters studied in both immature and mature monkeys. In general, these findings with prolactin suggests that PRL has a specific and definite influence on testicular neutral lipids and the response of different cellular compartments was found to vary.     

Tirumalin,a new prenylated dihydroflavonol from Rhynchosia cyanosperma

A new dihydroflavonol has been isolated together with the known flavonol-O- glycosides, rutin and kaempferol-3-rutinoside, and (+)-pinitol from the leaves of R. cyanosperma Benth. The dihydroflavonol was identified as (+)-(2R, 3R)-8-C-prenyltaxifolin-7, 4′-dimethyl ether on the basis of spectroscopic studies and the compound given the trivial name tirumalin.     

Flavone O- and C-glycosides of Rhynchosia beddomei

A new flavone-O-glycoside isolated front the leaves of Rhynchosia beddomei has been characterized as 3′,4′-di-O-methylluteolin-7-O-glucuronide.