Diffusion with rearranging traps

A model for diffusion on a cubic lattice with a random distribution of traps is developed. The traps are redistributed at certain time intervals. Such models are useful for describing systems showing dynamic disorder, such as ion-conducting polymers. In the present model the traps are infinite, unlike an earlier version with finite traps. For the infinite trap version a simple analytical calculation is possible and the results agree qualitatively with simulations.

Marjolin's ulcer of the suprapubic cystostomy site infiltrating the urinary bladder: a rare occurrence

We report a case of a 40-year-old man who had presented with a spontaneous suprapubic urinary leak from a well-healed suprapubic cystostomy tract scar, 20 years following a successful scrotal tube substitution urethroplasty done for a post-traumatic urethral stricture. Preoperative contrast studies suggested a recurrent bulbomembranous urethral stricture. Excision biopsy of the suprapubic fistulous tract revealed scar cancer infiltrating the bladder wall. Of 3 similar cases reported in the past, only 1 had bladder involvement. Ours is the second such case with bladder involvement.

DNA-cleavage studies on N-substituted monocyclic enediynes: enhancement of potency by incorporation of intercalating or electron poor aromatic ring and subsequent design of a novel phototriggerable acyclic enediyne

A number of novel N-substituted enediynes (azaenediynes) 1-4 were synthesized as DNA cleaving agents. Enhancement of DNA cleavage potency was observed with those compounds which could interact with DNA through intercalation of the extended aromatic ring or through electrostatic attraction with electron poor aromatic ring. An acyclic enediyne 5 with a novel phototriggerable device was also synthesized and its DNA-cleaving activity was established.

Luteolin, an abundant dietary component is a potent anti-leishmanial agent that acts by inducing topoisomerase II-mediated kinetoplast DNA cleavage leading to apoptosis

BACKGROUND

Plant-derived flavonoids, which occur abundantly in our daily dietary intake, possess antitumor, antibacterial, and free radical scavenging properties. They form active constituents of a number of herbal and traditional medicines. Several flavonoids have been shown to exert their action by interacting with DNA topoisomerases and promoting site-specific DNA cleavage. Therefore, flavonoids are potential candidates in drug design. We report here that, although the flavonoids luteolin and quercetin are potent antileishmanial agents, luteolin has great promise for acting as a lead compound in the chemotherapy of leishmaniasis, a major concern in developing countries.

MATERIALS AND METHODS

Kinetoplast DNA (kDNA) minicircle cleavage in drug-treated parasites was measured by electrophoresis of the total cellular DNA, followed by Southern hybridization using 32P labeled kDNA as a probe. Cell cycle progression and apoptosis were measured by flow cytometry using propidium iodide and fluorescein isothiocyanate (FITC)-labeled Annexin V.

RESULTS

Luteolin and quercetin inhibited the growth of Leishmania donovani promastigotes and amastigotes in vitro, inhibited DNA synthesis in promastigotes, and promoted topoisomerase-II-mediated linearization of kDNA minicircles. The IC50 values of luteolin and quercetin were 12.5 microM and 45.5 microM, respectively. These compounds arrest cell cycle progression in L. donovani promastigotes, leading to apoptosis. Luteolin has no effect on normal human T-cell blasts. Both luteolin and quercetin reduced splenic parasite burden in animal models.

CONCLUSION

Luteolin and quercetin are effective antileishmanial agents. Quercetin has nonspecific effects on normal human T cells, but luteolin appears nontoxic. So, luteolin can be a strong candidate for antileishmanial drug design.

Infundibulopelvic anatomy and clearance of inferior caliceal calculi with shock wave lithotripsy

PURPOSE

We evaluate the significance of inferior caliceal radiographic anatomy and determine its influence on successful fragmentation and clearance of inferior caliceal calculi with extracorporeal shock wave lithotripsy (ESWL).

MATERIALS AND METHODS

Between November 1996 and February 1998, 88 patients and 90 renal units with single or multiple inferior caliceal calculi of all sizes and composition were treated with ESWL. The size, number and area of calculi, length and width of the stone bearing inferior calix and infundibulopelvic angle were determined on pretreatment excretory urography. The infundibulopelvic angle was measured by 2 methods using the angle between the inferior caliceal infundibular and ureteral axes (angle 1), and between the infundibular and ureteropelvic axes (angle 2). Cases with residual fragments not clearing within 6 months of satisfactory fragmentation after lithotripsy were considered failures.

RESULTS

Overall stone clearance at 6 months was achieved in about 72% of the renal units. Infundibular length was 30 mm. or less in 77% of successful cases and in 64% of failures. Similarly, the smallest infundibular width of 5 mm. or more was found in 75% of successful cases compared to 41% of failures. Angle 1 of 35 degrees or more was observed in 73% of cases with compared to 18% without clearance. Angle 2 of 45 degrees or more was seen in 71% of successful cases compared to 9% of failures. The chances of a patient becoming stone-free with all favorable criteria of infundibular length 30 mm. or less, infundibular width 5 mm. or greater and infundibular ureteropelvic angle 45 degrees or greater was 100% (23 patients).

CONCLUSIONS

Radiographic features of a stone bearing inferior calix and its relation to the renal pelvis can be easily measured on standard excretory urography. An infundibular width of 5 mm. or more and infundibulopelvic angle 1 of 35 degrees or more or angle 2 of 45 degrees or more were statistically significant factors of radiographic anatomy in stone clearance following ESWL. Inferior caliceal length was not statistically significant, although length of 30 mm. or less appeared to be more favorable for stone clearance. The ideal treatment of inferior caliceal calculi in patients with all 3 favorable criteria is ESWL.

Cleogynol, a novel dammarane triterpenoid from Cleome gynandra

Chemical examination of Cleome gynandra (whole plant excluding seeds) led to the isolation and identification of a novel (20S, 24S)-epoxy-19,25-dihydroxydammarane-3-one hemiketal (1). The structure of the new compound, designated cleogynol, was determined using spectral and chemical methods.

Immunogenetic analysis of Buerger's disease in India

In order to understand the role of HLA linked factors in determining susceptibility to Buerger's disease, we have studied 21 unrelated Asian Indian patients belonging to the North Indian states of Punjab, Haryana, Uttar Pradesh and Delhi, representing mainly a lower socioeconomic background. The data was compared with healthy controls belonging to the same ethnic group. The study revealed an over representation of HLA-B40 (60+61) (chi2=6.12; P<0.02) and DR2 (chi2=10.2; P<0.002). Amongst the patients no particular association or linkage disequilibrium with any of the five alleles of the MIC-A gene could be derived in the small sample size studied.

Theoretical analysis of cell separation based on cell surface marker density

A theoretical analysis was performed to determine the number of fractions a multidisperse, immunomagnetically labeled cell population can be separated into based on the surface marker (antigen) density. A number of assumptions were made in this analysis: that there is a proportionality between the number of surface markers on the cell surface and the number of immunomagnetic labels bound; that this surface marker density is independent of the cell diameter; and that there is only the presence of magnetic and drag forces acting on the cell. Due to the normal distribution of cell diameters, a "randomizing" effect enters into the analysis, and an analogy between the "theoretical plate" analysis of distillation, adsorption, and chromatography can be made. Using the experimentally determined, normal distribution of cell diameters for human lymphocytes and a breast cancer cell line, and fluorescent activated cell screening data of specific surface marker distributions, examples of theoretical plate calculations were made and discussed.

Protein profile of the allergenic pollen of Ipomoea fistulosa L.--a comparative study

The pollen of Ipomoea fistulosa L. is an important aeroallergen of India. The pollen of this plant was collected from full bloomed flowers growing in different places of West Bengal, India. Protein content and profile were studied by SDS-PAGE. Skin-prick tests with pollen antigens of all the samples were also performed. Considerable variation in the protein content and profile was noted with the highest protein content in the collected sample of Calcutta showing highest number of protein bands (10) designated as IF1 to IF10 with their weights ranging between 31 kDa to 89 kDa and 3 bands (IF8, IF9 and IF10) having molecular weights less than 29 kDa. Skin-prick tests also revealed highest degree of sensitivity to the Calcutta sample giving positive response in 52% of the patients. Skin reactivity ranged between 1+ to 3+.

Analysis of the free amino acid content in pollen of nine Asteraceae species of known allergenic activity

The study reports the free amino acid composition of the pollen of nine members of the family Asteraceae, i.e. Ageratum conyzoides L., Blumea oxyodonta DC., Eupatorium odoratum L., Gnaphalium indicum L., Mikania scandens Willd., Parthenium hysterophorus L., Spilanthes acmella Murr., Vernonia cinerea (L.) Lees. and Xanthium strumarium L. by thin layer chromatography. The amino acid content was found to vary from 0.5-4.0% of the total dry weight. Fourteen amino acids were identified, among which amino-n-butyric acid, aspartic acid and proline were present in almost all pollen samples. The other major amino acids present in free form included arginine, cystine, glutamic acid, glycine, isoleucine, leucine, methionine, ornithine, tryptophan and tyrosine.

Pseudohypophosphatasia

Two rare cases of pseudohypophosphatasia in two siblings which so far, to best of our knowledge have not been reported.

1H NMR, EPR, UV-Vis, and Electrochemical Studies of Imidazole Complexes of Ru(III). Crystal Structures of cis-[(Im)(2)(NH(3))(4)Ru(III)]Br(3) and [(1MeIm)(6)Ru(II)]Cl(2).2H(2)O

Comparisons of the spectroscopic properties of a number of Ru(III) complexes of imidazole ligands provide methods of distinguishing between various types of bonding that can occur in proteins and nucleic acids. In particular, EPR and (1)H NMR parameters arising from the paramagnetism of Ru(III) should aid in determining binding sites of Ru(III) drugs in macromolecules. Electrochemical studies on several imidazole complexes of ruthenium suggest that imidazole may serve as a significant pi-acceptor ligand in the presence of anionic ligands. Crystal structures are reported on two active immunosuppressant complexes. cis-[(Im)(2)(NH(3))(4)Ru(III)]Br(3) crystallizes in the triclinic space group P&onemacr; (No. 2) with the cell parameters a = 8.961(2) Å, b = 12.677(3) Å, c = 7.630(2) Å, alpha = 98.03(2) degrees, beta = 100.68(2) degrees, gamma = 81.59(2) degrees, and Z = 2 (R = 0.044). [(1MeIm)(6)Ru(II)]Cl(2).2H(2)O crystallizes in the monoclinic space group P2(1)/n (No. 14) with the cell parameters a = 7.994(2) Å, b = 13.173(4) Å, c = 14.904(2) Å, beta = 97.89(1) degrees, and Z = 2 (R = 0.052). The average Ru(II)-N bond distance is 2.106(8) Å.

Effect of thyroxine on experimental bronchospasm in guinea pigs

Effect of Thyroxine was studied in histamine induced bronchospasm in guinea pigs. Chronic treatment with the drug significantly protected against experimental bronchospasm. Thyroxine also potentiated salbutamol evoked bronchodilation in this experimental model. Up-regulation of beta-2 adrenoceptors in bronchial smooth muscle may be the probable mechanism of action of thyroxine.

Cystic change in lymph nodes with metastatic squamous cell carcinoma

A retrospective analysis was performed of the gross characteristics of aspirated material in 335 consecutive cases of metastatic squamous cell carcinoma in cervical/supraclavicular lymph nodes seen during a three-year period. In 57 cases (17.01%), 1-2 mL of fluid was obtained. Microscopic examination of cytocentrifuge smears in all cases showed malignant squamous cells. Cystic change in lymph nodes harboring metastatic squamous cell carcinoma was frequently associated with a tongue primary (21/58 cases, 36.2%) followed by an esophageal primary (4/16 cases, 25%). The frequency of cystic change varied from 9.1% to 21.5% with primaries in the oral cavity, nasopharynx, lung, uterine cervix and unknown sites.

Synthesis and X-Ray Structural Characterization of the 1:1 Adduct of Bismuth(III) With the 'saltren' Anion ['saltren' ≡ N(CH2CH2N=CHC6H4OH)3]: A Novel Seven-Coordinate Bismuth(III) Complex

The synthesis and single-crystal X-ray structure determination of the title compound are recorded; crystals are monoclinic, P 21/c, a 10.309(8), b 18.817(7), c 15.542(6) Ǻ, β 121.80(5)°, Z 4; R was 0.038 for 2894 independent, 'observed' [I > 3σ(I)] reflections. The molecule has quasi-3 symmetry, with seven-coordinate bismuth [Bi-N(apical), 2.82(1); Bi-N, 2.512(8)-2.563(9); Bi-O, 2.197(8)-2.300(8)Ǻ].

Hyperaggregation of platelets detected by whole blood platelet aggregometry in newly diagnosed noninsulin-dependent diabetes mellitus

Twenty-five newly diagnosed cases of noninsulin-dependent diabetes mellitus were studied at the time of diagnosis and again after metabolic control of diabetes was achieved (approximately 3 months later) for platelet aggregation abnormalities in whole blood by the impedance method. Adenosine diphosphate in 10 and 20 mumol/L final concentrations and arachidonic acid in 25 and 50 mmol/L final concentrations were used as agonists. Patients had a significant hyperaggregation of platelets (P < 0.01) at the time of diagnosis compared with age-matched healthy control subjects. After metabolic control of blood glucose was achieved using oral hypoglycemic agents (n = 20) and diet regulation alone (n = 5), there was a significant decrease in platelet aggregation (P < 0.01). There was a positive relationship between blood glucose levels and whole blood platelet aggregation with adenosine diphosphate (P < 0.02 and < 0.05, with 10 mumol/L and 20 mumol/L, respectively), but there was no relationship between aggregation and glycosylated hemoglobin levels. Thus, platelet hyperaggregation was present even at the time of diagnosis in patients with diabetes mellitus in the absence of any vascular complications, and there was significant improvement in platelet hyperaggregation after metabolic control of blood glucose levels was achieved.

Ocimum sanctum Linn--a study on gastric ulceration and gastric secretion in rats

The antiulcerogenic property of Ocimum sanctum Linn (Tulsi) was studied in pyloric ligated and pyloric ligated & aspirin treated rats. The extract of OSL reduced the ulcer index, free & total acidity on acute and chronic administration. Seven days pretreatment with the drug increased the mucous secretion also. It may be concluded that OSL extract has antiulcerogenic property against experimental ulcers, and it is due to its ability to reduce acid secretion and increase mucous secretion.

Metabolism of silicon as a probable pathogenicity factor for Mycobacterium & Nocardia spp

The role of silicon (Si) in metabolism and growth of 22 strains of mycobacteria and 3 strains of nocardiae, which were mostly pathogenic, was studied on Kirchner's medium solidified with sodium metasilicate (KSM) and the C-free solidified metasilicate minimal medium (SMM) consisting of mineral salts only. On KSM, initial growth of mycobacteria appeared to be better, compared with that on Lowenstein-Jensen medium (LJM), although subsequent growth on the former was slower. On SMM lacking C, growth of mycobacteria and nocardiae could be achieved, only after repeated passages. These findings indicate that the mycobacteria and nocardiae are able to utilise Si at least to a limited extent, possibly as an alternative to C, with greater chances of survival.

Bacterial expression and secretion of various single-chain Fv genes encoding proteins specific for a Salmonella serotype B O-antigen

Active single-chain Fv molecules encoded by synthetic genes have been expressed and secreted to the periplasm of Escherichia coli using the ompA secretory signal. Four different constructs were developed to investigate the effects of peptide linker design and VL-VH orientation on expression, secretion, and binding to a Salmonella O-polysaccharide antigen. Peptide linker sequences derived from the elbow regions of the Fab molecule were used alone or in combination with the flexible (GGGGS)2 sequence. VL and VH domain order in the single chain molecules had a profound effect on the level of secretion but hardly influenced total expression levels, which were approximately 50 mg/liter, chiefly in the form of inclusion bodies. With VL in the NH2-terminal position, the amount of secreted product obtained was 2.4 mg/liter, but when VH occupied this position the yield was less than 5% of this value. Enzyme immunoassays of the four products showed domain order and linker sequence affected antigen binding by less than an order of magnitude. Attempts to express active Fv from dicistronic DNA were unsuccessful, but active Fv was obtained from single-chain Fv by enzymic cleavage at a site in the elbow linker peptide. The thermodynamic binding parameters of intact and cleaved single-chain Fvs determined by titration microcalorimetry were similar to those of bacterially produced Fab and mouse IgG.

Synthesis and expression in Escherichia coli of DNA encoding the murine lambda 1 chain of a monoclonal antibody specific for Salmonella serotype B O-antigen

A 658 bp DNA sequence corresponding to the murine lambda 1 chain of a monoclonal antibody, Se155-4, specific for the Salmonella serotype B O-antigen, was designed using Escherichia coli preferred codons and chemically synthesized by ligation of synthetic fragments into a linearized plasmid followed by transformation into E. coli. A synthetic signal peptide (ompA) was fused to express the L chain as a free polypeptide into the periplasm of E. coli cells. After isolation and purification, heterologous recombination of the E. coli L chain with mouse H chain gave an active antigen-binding protein. The activity was 15-20% when compared to protein created by an equivalent association of isolated natural mouse L and H chains as measured by a direct EIA assay. In inhibition experiments with the polysaccharide antigen, the two proteins showed identical titration curves and 50% inhibition points, indicating comparable KA values.

Multidrug resistant epidemic shigellosis in a village in west Bengal, 1984

An out break of acute bacillary dysentery in a village called Dhamasin in Hooghly district of West Bengal was investigated during March 1984. Forty seven percent of families were affected. A total of 91 cases and 2 deaths occurred amongst 937 people giving an over all attack rate of 9.7% and a case fatality rate of 2.2 percent. Highest attack rate (22.7%) was observed in below one year age group. Multiple drug resistant Shigella dysentery type 1 strains were isolated for the first time from 6 out of 22 cases sampled at the domiciliary level. The organism was never isolated earlier during last ten years of surveillance in the infectious Diseases Hospital, Calcutta. Identification of nature of this outbreak and it's causative agent helped to realise the potentiality of extensive spread and paved the way for further investigations. Public health authorities were buffled as the rapid spread of the disease throughout the entire state of West Bengal could not be contained in spite of instituting all probable control measures on war footing.

Inhibition of N-nitrosobenzylmethylamine-induced esophageal tumorigenesis in rats by ellagic acid

In this report, we describe the ability of ellagic acid (EA), a phenolic compound present in a number of fruits and nuts, to inhibit N-nitrosobenzylmethylamine (NBMA) tumorigenesis in the rat esophagus. When administered in a semi-purified diet at concentrations of 0.4 and 4 g/kg, EA produced a significant (21-55%) decrease in the average number of NBMA-induced esophageal tumors after 20 and 27 weeks of the bioassay. EA exhibited inhibitory effects toward preneoplastic lesions as well as neoplastic lesions. Tumors were not observed in vehicle-control rats or in rats that received EA alone.

Lactose- and heparin-inhibitable agglutinin from human fetal brain

An agglutinin activity which was sensitive to lactose and heparin was estimated during prenatal brain development. The agglutinin showed higher specific activities in cerebral cortex and midbrain. There was an increase in lectin specific activity in all the brain regions with development. In addition to brain, other fetal organs also showed the presence of developmentally regulated agglutinin. Cerebral cortical agglutinin was purified by Sepharose CL-6B gel filtration and asialofetuin- and heparin-Sepharose affinity chromatography. Purified agglutinin was strongly inhibited by lactose, asialofetuin, and heparin. It showed no requirement for divalent cations and was maximally active at pH 8.0. Electrophoretic characterization showed the aggregate nature of the agglutinin, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis gave subunit molecular weights of 58,000, 45,000, and 24,000.

Metabolic activation of 6-nitrochrysene in explants of human bronchus and in isolated rat hepatocytes

It has previously been shown that 6-nitrochrysene can be activated to electrophilic species capable of reacting with DNA through metabolic pathways that form N-hydroxy-6-aminochrysene or trans-1,2-dihydroxy-1,2-dihydro-6-aminochrysene as critical intermediates. Since the lung is a known target tissue for the carcinogenic action of polycyclic nitroaromatic hydrocarbons, we investigated the metabolism and DNA binding of [3H]6-nitrochrysene in 11 specimens of human bronchus. Analysis of medium from [3H]6-nitrochrysene-treated explants indicated the presence of trans-9,10-dihydroxy-9,10-dihydro-6-nitrochrysene (0.04-330 pmol/mg epithelial DNA), trans-1,2-dihydroxy-1,2-dihydro-6-nitrochrysene (12-1700 pmol/mg epithelial DNA), 6-aminochrysene (1.6-2200 pmol/mg epithelial DNA), and trans-1,2-dihydroxy-1,2-dihydro-6-aminochyrsene (3.6-610 pmol/mg epithelial DNA). Both the levels and the relative proportions of these metabolites varied widely in explants from different individuals. The amount of DNA recovered and the level of DNA modification were sufficient for adduct analysis in eight of the 11 cases for which metabolite data were obtained. Five additional bronchial specimens for which metabolite data were not obtained were also analyzed for carcinogen-DNA adducts. The levels of binding varied from 0.06 to 30.5 pmol [3H]6-nitrochrysene bound/mg DNA (two adducts per 10(8) nucleotides-10 adducts per 10(6) nucleotides). HPLC analyses of enzymatic hydrolysates of the explant DNA indicated that 11 of 13 cases contained adducts with retention times identical to those of adducts derived from trans-1,2-dihydroxy-1,2-dihydro-6-aminochrysene or N-hydroxy-6-aminochrysene. The adduct derived from trans-1,2-dihydroxy-1,2-dihydro-6-aminochrysene was the major adduct detected in eight of 13 cases. The reasons for the variation in metabolism and adduct formation observed in [3H]6-nitrochrysene-treated explants of bronchus from different donors are not known but may reflect differences in the activities of enzymes responsible for the metabolism of this compound. The influence of induction of drug metabolizing enzymes on the activation pathway of 6-nitrochrysene in an intact cell system was tested using rat hepatocytes. 6-Nitrochrysene was incubated with freshly isolated hepatocytes from rats that were either untreated or pretreated with phenobarbital, 3-methylcholanthrene or Aroclor 1254. Although the levels of adducts were similar in all cases, the pattern of DNA adducts formed in these hepatocytes was dependent on the nature of the pretreatment of the rats. As previously reported, hepatocytes from untreated rats contained adducts derived from N-hydroxy-6-aminochrysene.(ABSTRACT TRUNCATED AT 400 WORDS)

Inhibition of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced DNA adduct formation and tumorigenicity in the lung of F344 rats by dietary phenethyl isothiocyanate

F344 rats fed diets containing phenethyl isothiocyanate (PEITC, 3 mumol/g diet), a cruciferous vegetable component, before and during treatment with the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), developed about 50% fewer lung tumors than NNK-treated rats fed control diets. NNK-induced liver and nasal cavity tumors in rats were, however, not affected by this dietary treatment. The effects of PEITC diets on the formation of DNA adducts by NNK were also investigated in these target tissues. DNA methylation and pyridyloxobutylation by NNK were both decreased by 50% in lung of rats fed PEITC diets compared to that of rats fed control diets, but the levels of DNA methylation were not affected in liver and nasal mucosa. These results correlated with those from the carcinogenicity bioassay, suggesting that DNA alkylations could be used as indicators for screening inhibitors of NNK tumorigenesis. A slight increase in the number of tumors of the exocrine pancreas was observed in PEITC-fed rats with or without NNK treatments. However, these incidences were not statistically significant when compared to the control groups. The potential toxicity of PEITC at concentrations ranging from 0.75 mumol to 6 mumol/g diet was evaluated in a 13-week study. The only toxicity caused by this treatment was minimal fatty metamorphosis in the liver. Considering the widespread human exposure to NNK through tobacco use, it is of practical importance to demonstrate inhibition of lung tumors induced by this carcinogen. These results provide a basis for studies designed to discover agents of better efficacy for the prevention of NNK-induced tumorigenesis.

Inhibition of N-nitrosobenzylmethylamine metabolism and DNA binding in cultured rat esophagus by ellagic acid

The effect of ellagic acid (EA), a naturally occurring plant phenol, on the metabolism, DNA binding and DNA adduct formation of N-nitrosobenzylmethylamine (NBMA) in cultured explants of rat esophagus was investigated. Explants were incubated in medium containing EA at non-toxic concentrations of 10, 50 and 100 microM for 16 h, followed by the addition of 1 microM [3H]NBMA and EA for 12 h. Explant DNA was isolated by phenol extraction and hydroxylapatite chromatography, and benzaldehyde formation was determined by HPLC analysis of the culture medium. EA produced a significant inhibition in the total covalent binding of NBMA metabolites to DNA and in the production of benzaldehyde in the medium. After acid hydrolysis of the isolated DNA, the NBMA--DNA adducts were separated by HPLC. EA caused a dose-dependent decrease in the formation of N7-methylguanine and O6-methylguanine adducts. These results suggest that EA inhibits both the metabolism of NBMA and the binding of NBMA metabolites to DNA in cultured rat esophagus.

Cathepsin D and 2',3'-cyclic nucleotide 3'-phosphohydrolase in developing human foetal brain

Three peaks of proteinases were observed with hemoglobin, bovine serum albumin and casein as substrates at the pH of 3.5, 6.5 and 8.5, in prenatal human cerebral cortex. Cathepsin D (EC 3.4.23.5) was the most prominent, with hemoglobin as the preferred substrate. The enzyme was partially purified by Concanavalin A - Sepharose affinity chromatography and the nature of the active site was assessed with proteinase inhibitors. Inhibitor studies showed that similar to pepstatin A, benzethonium chloride was also strongly inhibitory to the enzyme. The distribution of cathepsin D, a neuronal marker, and 2',3'-cyclic nucleotide 3'-phosphohydrolase (EC 3.1.4.37), a oligodendroglial marker in foetal brain regions with increasing gestation revealed that neurogenesis and gliogenesis occur concomitantly from earlier periods of gestation. Glial marker acquisition was particularly high in medulla and in spinal cord between 20 and 25 weeks of gestation.

Inhibition of aflatoxin B1 mutagenesis in Salmonella typhimurium and DNA damage in cultured rat and human tracheobronchial tissues by ellagic acid

Ellagic acid (EA), a plant phenol found in various fruits and nuts, was examined for its ability to inhibit aflatoxin B1 (AFB1) mutagenesis in strain TA 100 of Salmonella typhimurium. In the presence of rat liver S-9 microsomal preparation, EA (1.5 microgram/plate) inhibited the number of mutations induced by AFB1 (0.5 microgram/plate) by 50%. EA at a dose of 1000 micrograms/plate inhibited the mutation frequency by greater than 90%. EA was also tested for its ability to inhibit the DNA binding and adduct formation of AFB1 in cultured explants of rat trachea and human tracheobronchus. Explants were incubated in medium containing EA at concentrations of 10, 50 and 100 microM for 16 h followed by the addition of 1 microM [3H]AFB1 and EA for 24 h. DNA was isolated by phenol extraction and hydroxylapatite chromatography. EA caused a dose-dependent inhibition in the covalent binding of AFB1 to the DNA of both the rat trachea (9-57% inhibition) and human tracheobronchus (24-79% inhibition). After acid hydrolysis of the isolated DNA, the AFB1-DNA adducts were separated by h.p.l.c. In tissues from both species, the major AFB1- DNA adducts were AFB1-N7-Gua [8,9-dihydro-8-(N7-guanyl)-9-hydroxyAFB1] and AFB1-N7-FaPyr (major) [8,9-dihydro-8- (2,6-diamino-4-oxo-3,4-dihydropyrimid-5-yl formamido)-9-hydroxyAFB1], and the formation of these adducts was reduced by 28-76% in the presence of EA. These data indicate that EA has the potential to act as a naturally occurring inhibitor of AFB1-related respiratory damage in rats and in humans.

Biochemical changes in testis and ovary of Chrysocoris stolli Wolf. after the application of juvenoid and ecdysterone

The changes in the metabolic status of both testis and ovary of Chrysocoris stolli following the treatment with juvenile hormone analogue (JHa) and ecdysterone were studied. After the exogenous application of JHa in selective dose, total carbohydrate, glycogen, trehalose, cholesterol, ascorbic acid and inorganic phosphorus increased significantly whereas free fatty acid (FFA), phospholipid, total protein, RNA and DNA decreased significantly in comparison to control of both testis and ovary. Total lipid significantly decreased in testis and significantly increased in ovary after JHa injection. The activities of cellular enzymes like alkaline phosphatase, 5' nucleotidase, catalase and peroxidase significantly decreased while acid phosphatase and GPT significantly increased after the JHa application in comparison to control both in testis and ovary. Activities of GOT and general esterase significantly decreased in testis and increased in ovary after JHa application. The exogenous application of ecdysterone also brought about the similar kind of responses as was noticed in case of JHa treatment but these two treatments differed in some cases such as ecdysteroid that produced some results which were just the reverse of what was produced by JHa treatment. The results obtained here were explained in terms of mode of action of these two hormones.