Antioxidant activity of brahma rasayana

Free oxygen radical scavenging activity of brahma rasayana (BR) was studied by in vitro and in vivo models. Addition of aqueous extract of BR was found to scavenge the lipid peroxides already present in rat liver homogenate (IC50 700 micrograms/ml) and inhibit the lipid peroxide generated by Fe(2+)-ascorbate (IC50 2600 micrograms/ml) and Fe(3+)-ADP-ascorbate system (IC50 1200 micrograms/ml). BR was found to scavenge the hydroxyl radical generated by Fenton reaction (IC50 7400 micrograms/ml) and superoxide generated by photoreduction of riboflavin (IC50 180 micrograms/ml). BR was also found to inhibit the nitric oxide radical generated in vitro from sodium nitroprusside (IC50 5.5 micrograms/ml). Oral administration of BR (50 mg/dose/animal) was found to inhibit the PMA induced superoxide generation in mice peritoneal macrophages. Oral administration of BR; 10 and 50 mg/dose/animal was also found to inhibit the nitrite production in peritoneal macrophages and percentage inhibition was 25.2% and 37.8% respectively. These results indicate significant antioxidant activity of BR in vitro and in vivo.     

Effect of brahma rasayana on antioxidant system after radiation

Oral administration of brahma rasayana (BR; 50 mg/animal for 10 and 30 days) significantly increased the liver antioxidant enzymes such as superoxide dismutase (SOD), catalase(CAT) and tissue and serum levels of reduced glutathione (GSH). Whole body irradiation suppressed the levels of SOD, CAT and GSH. Reduced activity of SOD, CAT and GSH was significantly elevated by treatment with BR after radiation treatment. Similarly radiation exposure induced increase in serum and liver lipid peroxides was significantly reduced by further treatment with BR. The results indicate that BR could ameliorate the oxidative damage produced in the body by radiation and may be useful as an adjuvant during radiation therapy.     

Inhibition of 5-amino levulinic acid dehydratase activity by arsenic in excised etiolated maize leaf segments during greening

In vivo as well as in vitro supply of sodium arsenate inhibited the 5-Amino levulinic acid dehydratase (5-aminolevulinate-hydrolyase EC 4.2.1.24, ALAD) activity in excised etiolated maize leaf segments during greening. The percent inhibition of enzyme activity by arsenate (As) was reduced by the supply of KNO3, but it was increased by the glutamine and GSH. Various inhibitors, such as, chloramphenicol, cycloheximide and LA, decreased the % inhibition of enzyme activity by As. The % inhibition of enzyme activity was also reduced by in vivo supply of DTNB. The enzyme activity was reduced substantially by in vitro inclusion of LA, both in the absence and presence of As. In vitro inclusion of DTNB and GSH inhibited the enzyme activity extracted from leaf segments treated without arsenate (-As enzyme) and caused respectively no effect and stimulatory effect on arsenate treated enzyme (+As enzyme). Increasing concentration of ALA during assay increased the activity of -As enzyme and +As enzyme to different extent, but double reciprocal plots for both the enzymes were biphasic and yielded distinct S0.5 values for the two enzymes (-As enzyme, 40 micromol/L and +As enzyme, 145 micromol/L) at lower concentration range of ALA only. It is suggested that As inhibits ALAD activity in greening maize leaf segments by affecting its thiol groups and/or binding of ALA to the enzyme.     

Uterovaginal packing with rolled gauze in postpartum hemorrhage

Management options for postpartum hemorrhage (PPH) include oxytocics, prostaglandins, genital tract exploration, ligation or angiographic embolization of uterine/internal iliac arteries, and hysterectomy. After excluding uterine rupture, genital tract lacerations, and retained placental tissue, efforts are directed toward contracting the uterus by bimanual compression and oxytocics. If these are not successful, one must resort to surgical techniques. At this stage, an alternative option to remember is uterovaginal packing. Easy and quick to perform, it may be used to control bleeding by tamponade effect and stabilize the patient until a surgical procedure is arranged. Uterovaginal packing may sometimes obviate the need for surgery altogether. Two cases, a primary and a secondary PPH, managed recently with uterovaginal packing are reported. Despite concerns about concealed hemorrhage or the development of infection with this intervention, none of these problems were encountered, and uterine packing was successful even in the case of secondary PPH with documented infection.     

Hyperphosphorylation of extracellular regulated kinase 2 (ERK2) and inhibition of JNK2 phosphorylation are associated with increased S-phase during transformation of Syrian hamster embryo cells by Malachite Green

Malachite Green (MG), consisting of green crystals with a metallic lustre, is highly soluble in water, cytotoxic to various mammalian cells and also acts as a liver tumour promoter. In view of its industrial importance and possible exposure to human beings, MG poses a potential environmental health hazard. We have earlier reported the malignant transformation of Syrian hamster embryo (SHE) cells in primary culture by MG. In this study, we have studied the mitogen activated protein (MAP) kinase signal transduction pathway in preneoplastic cells induced by MG. Western blots of MG induced preneoplastic cells showed no phosphorylation of ERK1, an increased phosphoactive ERK2 associated with a decreased expression of phosphoactive JNK2. However, total forms of ERKs, JNKs and p38 Kinases showed similar levels of expression in control and preneoplastic SHE cells. Indirect immunofluorescence studies have shown a distinct nuclear localisation of phosphoactive ERKs in MG induced preneoplastic cells. Flow cytometric analysis showed an increase of S-phase cells in preneoplastic cells compared to control SHE cells. The present study indicates that hyperphosphorylation of ERK2, decreased JNK2 phosphorylation and an increase in S-phase cells seems to be the early changes associated with the MG induced malignant transformation of SHE cells in primary culture.     

Catecholamines act via a beta-adrenergic receptor to maintain fetal heart rate and survival

Mice lacking catecholamines die before birth, some with cardiovascular abnormalities. To investigate the role of catecholamines in development, embryonic day 12.5 (E12.5) fetuses were cultured and heart rate monitored. Under optimal oxygenation, wild-type and catecholamine-deficient fetuses had the same initial heart rate (200-220 beats/min), which decreased by 15% in wild-type fetuses during 50 min of culture. During the same culture period, catecholamine-deficient fetuses dropped their heart rate by 35%. Hypoxia reduced heart rate of wild-type fetuses by 35-40% in culture and by 20% in utero, assessed by echocardiography. However, catecholamine-deficient fetuses exhibited greater hypoxia-induced bradycardia, reducing their heart rate by 70-75% in culture. Isoproterenol, a beta-adrenergic receptor (beta-AR) agonist, reversed this extreme bradycardia, restoring the rate of catecholamine-deficient fetuses to that of nonmutant siblings. Moreover, isoproterenol rescued 100% of catecholamine-deficient pups to birth in a dose-dependent, stereo-specific manner when administered in the dam's drinking water. An alpha-AR agonist was without effect. When wild-type fetuses were cultured with adrenoreceptor antagonists to create pharmacological nulls, blockade of alpha-ARs with 10 microM phentolamine or beta-ARs with 10 microM bupranolol alone or in combination did not reduce heart rate under optimal oxygenation. However, when combined with hypoxia, beta-AR blockade reduced heart rate by 35%. In contrast, the muscarinic blocker atropine and the alpha-AR antagonist phentolamine had no effect. These data suggest that beta-ARs mediate survival in vivo and regulate heart rate in culture. We hypothesize that norepinephrine, acting through beta-ARs, maintains fetal heart rate during periods of transient hypoxia that occur throughout gestation, and that catecholamine-deficient fetuses die because they cannot withstand hypoxia-induced bradycardia.     

pH-dependent amyloid and protofibril formation by the ABri peptide of familial British dementia

The ABri is a 34 residue peptide that is the major component of amyloid deposits in familial British dementia. In the amyloid deposits, the ABri peptide adopts aggregated beta-pleated sheet structures, similar to those formed by the Abeta peptide of Alzheimer's disease and other amyloid forming proteins. As a first step toward elucidating the molecular mechanisms of the beta-amyloidosis, we explored the ability of the environmental variables (pH and peptide concentration) to promote beta-sheet fibril structures for synthetic ABri peptides. The secondary structures and fibril morphology were characterized in parallel using circular dichroism, atomic force microscopy, negative stain electron microscopy, Congo red, and thioflavin-T fluorescence spectroscopic techniques. As seen with other amyloid proteins, the ABri fibrils had characteristic binding with Congo red and thioflavin-T, and the relative amounts of beta-sheet and amyloid fibril-like structures are influenced strongly by pH. In the acidic pH range 3.1-4.3, the ABri peptide adopts almost exclusively random structure and a predominantly monomeric aggregation state, on the basis of analytical ultracentrifugation measurements. At neutral pH, 7.1-7.3, the ABri peptide had limited solubility and produced spherical and amorphous aggregates with predominantly beta-sheet secondary structure, whereas at slightly acidic pH, 4.9, spherical aggregates, intermediate-sized protofibrils, and larger-sized mature amyloid fibrils were detected by atomic force microscopy. With aging at pH 4.9, the protofibrils underwent further association and eventually formed mature fibrils. The presence of small amounts of aggregated peptide material or seeds encourage fibril formation at neutral pH, suggesting that generation of such seeds in vivo could promote amyloid formation. At slightly basic pH, 9.0, scrambling of the Cys5-Cys22 disulfide bond occurred, which could lead to the formation of covalently linked aggregates. The presence of the protofibrils and the enhanced aggregation at slightly acidic pH is consistent with the behavior of other amyloid-forming proteins, which supports the premise that a common mechanism may be involved in protein misfolding and beta-amyloidosis.     

The myelin-axolemmal complex: biochemical dissection and the role of galactosphingolipids

Myelin-axolemmal interactions regulate many cellular and molecular events, including gene expression, oligodendrocyte survival and ion channel clustering. Here we report the biochemical fractionation and enrichment of distinct subcellular domains from myelinated nerve fibers. Using antibodies against proteins found in compact myelin, non-compact myelin and axolemma, we show that a rigorous procedure designed to purify myelin also results in the isolation of the myelin-axolemmal complex, a high-affinity protein complex consisting of axonal and oligodendroglial components. Further, the isolation of distinct subcellular domains from galactolipid-deficient mice with disrupted axoglial junctions is altered in a manner consistent with the delocalization of axolemmal proteins observed in these animals. These results suggest a paradigm for identification of proteins involved in neuroglial signaling.