Synthesis and anticancer activity of sclerophytin-inspired hydroisobenzofurans

Three structurally related sets of hydroisobenzofuran analogs of sclerophytin A were prepared in three or four steps from (S)-(+)-carvone via an aldol-cycloaldol sequence. The most potent members of each set of analogs exhibited IC₅₀’s of 1–3 μM in growth inhibitory assays against KB3 cells. The NCI 60-cell line 5-dose assay for analog 6h revealed a GI₅₀ = 0.148 μM and LC₅₀ = 9.36 μM for the RPMI-8226 leukemia cell line, and a GI₅₀ = 0.552 μM and LC₅₀ = 26.8 μM for the HOP-92 non-small cell lung cancer cell line.     

Effect of chronic choline availability on lung and lymph nodes of rat

Male albino rats were given intraperitoneal injections of choline chloride (0. 1,0.33 or 0.5 × lethal dose 50) for a total period of one month and then killed at the end of 30,90 and 240 days for the study of pathotoxicokinetics of choline. Chronic choline administration in rats caused a decrease in growth rate, a dose dependent modulating effect on the somatic tissue indices of lung and lymph nodes, as well as cellularity of lymph nodes. In another experiment, the effect of choline on mica induced pulmonary lesions was studied. The combined effect of choline and mica caused adenocarcinoma of bronchiolar epithelium and marked lymphadenopathy with abnormal cells in the lymph nodes at the termination of experiment (330 days). The results of the present investigation suggest that excess choline availability not only produces pulmonary pathological lesions by itself but it also further enhances the lung lesions in altered pulmonary conditions     

Attempted sexing of bovine spermatozoa by fractionation on a Percoll density gradient

Bovine spermatozoa were fractionated on Percoll density gradients into two major subpopulations of motile spermatozoa and a minor fraction containing mostly nonmotile spermatozoa with abnormal morphology. Fractionation required the addition of bovine serum albumin and a continuous Percoll gradient buffered with sodium bicarbonate. It is postulated that, under suitable ionic conditions, the binding of bovine serum albumin to spermatozoa amplifies subtle differences between subpopulations. These studies were directed toward separating Y- and X-bearing spermatozoa. However, when the subpopulations were evaluated by flow cytometry, their Y:X ratios were similar to that of an unfractionated control.     

Micropropagation ofBauhinia vahlii Wight & Arnott — a leguminous liana

Anin vitro propagation protocol for a leguminous liana,Bauhinia vahlii, has been established. In the first experiment, cotyledonary nodes fromin-vitro-germinated seedlings were cultured on various basic media (Murashige and Skoog medium, Woody Plant medium, B5, and 1/2 Murashige and Skoog medium) containing 1.0M thidiazuron. Shoot proliferation (96.20%) and multiplication (5.55 shoots/explant) was best when cultured on Murashige and Skoog medium. The second experiment compared responses to benzylaminopurine, kinetin, zeatin and thidiazuron. Murashige and Skoog medium supplemented with 1.0M thidiazuron proved most effective for both shoot proliferation and shoot multiplication. The effect of cytokinin type and concentration and their interaction was found to be significant (P<0.001) for explant proliferation, shoot number and length. Subsequent rooting (55.14%) of the regenerated shoots was achieved on half-strength Murashige and Skoog medium supplemented with IM 1- naphthaleneacetic acid. Successful transfer of regenerants to soil has been accomplished, and efforts are being made to gradually transfer them to field conditions.     

A step towards developing the expertise to control hunger and satiety: Regulatory role of satiomem—A membrane proteoglycan

Regulation of hunger and satiety is a complex process thought to be controlled by a complex interplay of neurotransmitters in the hypothalamic region of the brain. Reduced food intake or anorexia has also been observed under various disease or disorder conditions including AIDS and cancer. On the other hand, increased appetite because of some impairment of central mechanisms regulating the food intake could also cause obesity. A large number of substances including neuropeptides, hormones, drugs, and synthetic peptides have been implicated in the regulation of appetite and food intake behavior in normal as well as disease or disorder conditions. Most of these substances are not directly involved in the regulation of normal hunger and satiety but exert their effect indirectly via other media. Some of them are involved under certain pathologic conditions and during the course they become involved directly or indirectly in the triggering of hunger and satiety regulatory mechanism. Recently, we have been able to isolate and purify an endogenous proteoglycan from membranes of animal and plant sources. This membrane anchored proteoglycan termed as Satiomem reduces food intake without any rebound effects and has no apparent toxicity. It also fulfils all the criteria of a true satiety or anorexigenic substance. The release of satiomem from the cell surface could be mediated by a specific phospholipase-C. Satiomem seems to be involved in transducing activating signals and may also act as a source of second messenger for the regulatory mechanism of appetite. This article summarizes the regulatory aspects of hunger and satiety mechanisms controlled by endogenous substances with the emphasis on our present knowledge about satiomem.Dedicated to Dr. Sydney Ochs.     

A mathematical model of fatty acid metabolism and VLDL assembly in human liver

The lipid composition of very-low-density lipoprotein (VLDL) in plasma is crucial for human health. A pre-requisite for the alteration of VLDL composition is a co-ordinated understanding of the complex interactions in VLDL assembly. In order to determine the potential effects of changes in substrate availability on VLDL lipid composition, we constructed, parameterized and evaluated a mechanistic mathematical model of the biosynthesis of triglycerides, phospholipids, and cholesterol esters and the assembly of VLDL in human hepatocytes. Using published data on human liver metabolism, the model was also used to provide insight into the complex process of lipid metabolism and to estimate the affinities of different liver enzymes for different fatty acids (FA). For example, we found that Delta6-desaturase is 19 times more selective for C18:3n-3 than C18:2n-6, stearoyl-CoA-desaturase is 2.7 times more selective for C18:0 than C16:0, Delta5-desaturase desaturates C20:4n-3 preferentially over C20:3n-6 and FA elongase preferentially elongates C18:3n-6. The model was also used to predict the plasma free fatty acid (FFA) composition required to generate a prescribed change in plasma lipoprotein FA composition. Furthermore, the model was tested against a published human feeding trial that investigated the effect of changes in dietary FA composition on human plasma lipid FA composition. The model is a useful tool for predicting the effect of changes in plasma FFA composition on plasma lipoprotein lipid FA composition.     

Vinblastine-induced apoptosis is mediated by discrete alterations in subcellular location, oligomeric structure, and activation status of specific Bcl-2 family members

To gain a broader insight into the role of Bcl-2 proteins in apoptosis induced after mitotic arrest, we investigated the subcellular location, oligomeric structure, and protein interactions of Bax, Bcl-2, and Bcl-xL in vinblastine-treated KB-3 cells. Vinblastine induced the translocation of Bax from the cytosol to the mitochondria, which was accompanied by conformational activation and oligomerization of Bax. Bcl-2 was located in the mitochondria, underwent multisite phosphorylation after vinblastine treatment, and was strictly monomeric under all conditions. In contrast, in control cells, Bcl-xL existed in both monomeric (30 kDa) and oligomeric (150 kDa) forms. Treatment with agents that induced Bcl-xL phosphorylation (microtubule inhibitors) caused loss of the 150-kDa form, but this species was unaffected by apoptotic stimuli that did not stimulate phosphorylation. Vinblastine also promoted Bax activation and Bax oligomerization in HCT116 colon cancer cells. Both wild-type and Bax-deficient HCT116 cells expressed the 150-kDa form of Bcl-xL, which was depleted similarly in both cell lines upon vinblastine treatment. Co-immunoprecipitation studies revealed that in untreated KB-3 cells inactive cytosolic Bax interacted with Bcl-xL, whereas in vinblastine-treated cells, activated mitochondrial Bax did not interact with Bcl-xL. Interaction of Bcl-2 with Bax was not observed under any condition. Overexpression of Bcl-xL inhibited vinblastine-induced Bax activation and Bax dimerization and in parallel inhibited apoptosis. The results indicate that vinblastine-induced apoptosis requires translocation, activation, and oligomerization of Bax and is associated with specific changes in the oligomeric properties of Bcl-xL, which occur independently of Bax.     

Determination of endogenous glycosaminoglycans derived disaccharides in human plasma by HPLC: validation and application in a clinical study

SB-424323 is a new, orally active anti-thrombotic agent presently in phase-II clinical development, with limited hemorrhagic risk and a unique mechanism of action involving the induction of glycosaminoglycans (GAGs) biosynthesis. The objective of the present study was to develop a simple and rapid high performance liquid chromatography (HPLC) method for determination of endogenous GAGs derived disaccharides in plasma samples from a phase-II clinical study of SB-424323. Sample preparation was a simple heat treatment of the diluted plasma followed by digestion of endogenous GAGs with chondroitinase ABC to yield unsaturated disaccharides, 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-D-galactose (DeltaDi-0S), 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-4-O-sulfo-D-galactose (DeltaDi-4S), and 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-6-O-sulfo-D-galactose (DeltaDi-6S). These disaccharides were recovered and purified using centrifugal filtration through a filter with 3000 molecular weight cut-off along with externally added internal standard 2-acetamido-2-deoxy-3-O-(2-O-sulfo-beta-D-gluco-4-enepyranosyluronic acid)-D-galactose (DeltaDi-UA2S). A gradient reverse phase HPLC separation was developed on a Waters Symmetry C(18) column (4.6 mm x 150 mm, 5 microm) with a gradient mobile phase system consisting of 0.8 mM tetrabutylammonium hydrogen sulfate and 2mM sodium chloride and acetonitrile at a flow rate of 1.0 mL/min. The eluate was monitored with an ultraviolet detector set at 230 nm. Plasma standard curves were linear (r(2)> or =0.994) in the concentration range 1.0-20 microg/mL with a lower limit of quantification (LLOQ) of 1.0 microg/mL for each of the disaccharide. The mean measured quality control (QC) concentrations for the disaccharides deviated from the nominal concentrations in the range of -8.92 to 5.61% and -16.3 to 16.7%, for inter and intra-day, respectively. The inter and intra-day precision in the measurement of QC samples, were in the range of 3.21 to 18.2% relative standard deviation (R.S.D.) and 0.32 to 20.9% R.S.D., respectively. The inter and intra-day precision in the measurement of endogenous GAGs derived disaccharides in human control plasma, were in the range of 5.8 to 15.9% R.S.D. and 1.17 to 7.74% R.S.D., respectively. Stability of the processed samples was confirmed up to 48 h in the auto-sampler. The method is simple, reliable, and easily adaptable to analysis of large number of samples under logistics of a clinical study. The present method has been used to investigate the GAGs levels in the plasma of patients in a phase II clinical study of SB-424323.     

ISSR and DAMD markers revealed high genetic variability within Flavoparmelia caperata in Western Himalaya (India)

Flavoparmelia caperata (L.) Hale is medicinally very important and possesses antifungal and antibacterial activities. F. caperata is the only species found in India. Inter simple sequence repeat (ISSR) and Directed amplification of minisatellite DNA (DAMD) methods were used to analyze the genetic variability within F. caperata from the Western Himalayan region of India. Eleven ISSR and 10 DAMD primers produced 139 and 117 polymorphic bands, and detected 91.44 and 82.34 % polymorphisms, respectively. Cumulative band data generated for ISSR and DAMD markers resulted in 86.86 % polymorphism across all the accessions of F. caperata. The average Polymorphic information content (PIC) value obtained with ISSR, DAMD, and cumulative band data were 0.28, 0.27, and 0.27, respectively. The clustering of the F. caperata accessions in the UPGMA dendrogram showed that these accessions are intermingled with each other in different subclusters irrespective of their geographical affiliations. The pattern of genetic variations within F. caperata accessions could be due to free exchange of spores that might have taken place among these accessions in the wild. ISSR and DAMD markers efficiently and reliably resulted in discrete banding patterns and polymorphic profiles. These markers despite targeting different regions of genome, revealed almost similar levels of polymorphism across all the accessions. The wide range of genetic distance and high level of polymorphism detected by ISSR and DAMD reflected a high genetic variability among the different accessions of F. caperata.