7-Ethoxy-3,4-dimethylcoumarin: a substrate for a cytochrome P450-mediated mono-oxygenase activity that is highly induced by phenobarbitone and beta-naphthoflavone

The O-dealkylation of 7-ethoxy-3,4-dimethylcoumarin in rat liver microsomes was catalysed in a typical cytochrome P450-mediated reaction as judged by cofactor requirement and inhibition criteria, and displayed monophasic Michaelis-Menten kinetics. When measured at low substrate concentration, this activity was highly inducible by treatment with phenobarbitone or beta-naphthoflavone (44- and 78-fold induction, respectively). These data indicate the potential usefulness of this activity as a probe for P4501A1- and P4502B-mediated activities. The O-dealkylation of 7-methoxy- and 7-propoxy-3,4-dimethylcoumarin were much less inducible.

Study of Biaxial Stress Induced by Cosputtered Thin Molybdenum Silicide Films in Silicon Single-Crystal Substrates

Bending of 25 mm-diameter (100) silicon wafers produced by 100 nm-thick cosputtered molybdenum–silicon films has been investigated just after deposition, after rapid thermal annealing and after etching of the deposits. Values of biaxial stress in the films were determined by the use of a widely used relation. The Mo:Si ratio in the as-deposited films was 89:11. Radii of curvature of substrates were measured by a double-crystal X-ray diffractometer. Blank wafers with three widely different radii of curvature (33, 62 and 250 m) were chosen as specimens and their curvatures were taken into account in the determination of the value of biaxial stress in wafers with deposits. All the wafers were convex when viewed from the polished surface side on which the films were deposited. Values of σ for wafers with as-deposited films were in the range 3 × 108 to 14 × 108 Nm−2 (tensile). Wafers with higher initial bending showed higher values of stress. Deposition led to degradation of perfection, as revealed by broadening of the diffraction curves and the contrast in the topographs. Rapid thermal annealing at 1273 and 1373 K (3–4 min) led to formation of the MoSi2 phase and to a notable relaxation of stress. The values of σ were in the range 1 × 107 to ~6 × 108 N m−2 (tensile). The value of the stress was lowest for the blank wafer with smallest bending. Annealing also improved the degree of crystalline perfection of the silicon. Experiments performed after etching of the annealed specimens showed no significant change in the radii of curvature.

Effects of bleomycin and Staphylococcus protein-A on lungs of mice

Fibrosis of organs and tissues are major causes of morbidity and mortality in human. The currently available pharmacologically based treatments are unsatisfactory. As an experimental animal model antitumor antibiotic drug bleomycin (BLM) is widely used to produce lung fibrosis. The present study has been undertaken to investigate the possible role of a potent immunomodulator Staphylococcus protein-A (SpA) in the modulation of lung lesions caused by treatment of BLM. In mice BLM, 0.5 mg in 200 microliters of normal saline and SpA, 6 micrograms in 200 microliters of normal saline was administered singly or in combination twice a week for 4 weeks. The fibrotic lesions in the lungs were observed after 4 weeks of BLM treatment. After 4 weeks treatment of SpA, the hyperreactive changes in bronchi and bronchioles were observed. In the co-treatment group of BLM and SpA, the effects observed were in the form of enhanced lesions in the lung parenchyma. Moreover, the pleural lesions were also observed in co-treatment group (BLM + SpA). Opposite to the assumption, SpA being a potent immunomodulator was not able to reduce the lung lesions produced by BLM.

Identification of two novel mutations in non-Jewish factor XI deficiency

We have studied two heterozygous unrelated CRM- non-Jewish FXI-deficient patients. Neither of the patients carries a previously described mutation. Their FXI genes were screened by SSCP analysis following PCR amplification of each exon and the flanking intronic sequences. DNA fragments showing aberrant mobility were cloned and sequenced. The following mutations were identified: in case 1, a T to G transition in exon 12 results in the substitution of Phe-442 by Val (FXI-F442V); in case 2 a C to A transition in exon 5 results in the substitution of Cys-128 by a nonsense codon (FXI-C128X). The missense mutation results in a substitution within the protease domain of FXI. Molecular modelling locates this residue in a structurally conserved region of the protease domain and the amino acid substitution may therefore interfere with either chain folding and subsequent secretion or the stability of the protein in plasma. We conclude that the mutations which we have identified are responsible for the inherited abnormality in these patients.

Exocrine granule specific packaging signals are present in the polypeptide moiety of the pancreatic granule membrane protein GP2 and in amylase: implications for protein targeting to secretory granules

The mechanisms for segregation of secretory and membrane proteins incorporated into storage granules from those transported constitutively have been thought to be conserved in diverse cell types, including exocrine and endocrine cells. However, GP2, the major protein of pancreatic zymogen granule membranes, in its native glycosyl phosphatidylinositol (GPI)-linked form, is incorporated into secretory granules when expressed in exocrine pancreatic AR42J cells, but not in the endocrine cells such as pituitary AtT20. To determine whether the protein moiety of GP2 contains the cell-type specific information for packaging into granules, a secretory form of GP2 (GP2-GPI-), with the GPI attachment site deleted, was generated and introduced into AR42J and AtT20 cells. Like native GP2, GP2-GPI- localized to the zymogen-like granules of AR42J cells and underwent regulated secretion. In AtT20 cells expressing GP2-GPI-, however, the protein was secreted by the constitutive pathway. Thus, a granule packaging signal is present in the luminal portion of GP2 that is functional only in the exocrine cells. However, this cell-type dependent sorting process is not limited to GP2 or membrane proteins. Amylase, a major content protein of pancreatic acinar and serous salivary gland granules, was also secreted exclusively by the constitutive pathway when expressed in AtT20 cells. The cell-type specific targeting of GP2 to granules correlated with its behavior in an in vitro aggregation assay where it co-aggregated more effectively with content proteins from pancreatic zymogen granules than with those from pituitary granules.(ABSTRACT TRUNCATED AT 250 WORDS)

Histomorphological changes in lung of rats following exposure to wood smoke

Rats were exposed to repeated, intermittent exposure to smoke generated from combustion of 1g wood/15 min, total period for 75 min daily under dynamic exposure conditions, over a period of 15, 30 and 45 days. First 15 days exposure caused mild bronchiolitis, hyperplasia and hypertrophy of bronchiolar epithelial lining cells, some necrosed lining cells desquamated into lumens, congestion of parenchymatous blood vessels, oedema, hyperplasia of lymphoid follicles, peribronchiolar and perivascular infiltration of polymorphonuclear cells, and mild emphysema. These lesions progressed further during 30 and 45 days of exposure, though emphysematous changes remain constant. By 30 days and 45 days, hyperplastic and hypertrophic changes of bronchioles become quite marked, with mononuclear cells infiltration and alveolar septa thickening. Hematological studies show marginal alterations in hemoglobin levels, ESR, PCV and TLCS during 15 days, where as significant changes in eosinophil were observed during 30 and 45 days, and ESR during 45 days only. The results indicate progressive pathomorphological pulmonary lesions with subsequent exposure to wood smoke in controlled conditions.

Salivary proteolysis of histidine-rich polypeptides and the antifungal activity of peptide degradation products

Incubation of purified synthetic histidine-rich polypeptides, HRP-2, -3, -4, -5, -6 (histatins), with diluted human parotid saliva yielded a series of peptide degradation products whose structures could be determined by gas-phase sequencing of cationic polyacrylamide gel electroblots. Sequencing indicated that two and sometimes three peptides were present in the same Coomassie blue-stained band. By comparing different individuals' salivas it was observed that structural variation occurs, perhaps due to differences in the concentrations or specific activities of salivary proteases. Based on the structural data, four proteolytic enzyme activities are proposed. A trypsin-like and chymotrypsin-like enzymatic activity(s) appear to represent the most active salivary protease; however, both an alanine-lysine endopeptidase and a histidine peptidase activity are also present in parotid saliva. In comparison to HRP-4 or HRP-6, degraded products were less active as antifungal agents against Candida albicans both in blastospore and germ-tube assays.

Histatins 2 and 4 are autoproteolytic degradation products of human parotid saliva

Freshly collected human parotid saliva contains 8 cationic proteins, as demonstrated by capillary electrophoresis. These proteins include lysozyme, histatin 6 and the 6 salivary histidine-rich polypeptides (HRPs 1-6). Neither histatin 2 nor histatin 4 are present in native undegraded parotid saliva but appear only after autoproteolytic degradation of the saliva. Histatin 2 appears to arise through slow degradation of HRP-1, and histatin 4 is mainly produced as a rapid breakdown product of HRP-3.

One-step purification of histidine-rich polypeptides form human parotid saliva and determination of anti-candidal activity

Immunoadsorption affinity chromatography was used to selectively purify the family of the histidine-rich polypeptides (HRPs) from human parotid saliva. The immunoadsorbent was prepared by coupling an enriched preparation of horse anti-(HRPs 2, 3, 4, 5 and 6) IgG to protein G. Both freshly collected stimulated untreated and acidified boiled salivas (5 ml) were applied to the affinity column. When native saliva was used it appeared that all of the components of saliva, with the exception of the HRPs, were present in the fraction nonadsorbed to the affinity column; however, recovery of the HRPs with 0.2 M sodium acetate-HCl, pH 1.8, was poor. Yields of HRPs desorbed from the column with the pH 1.8 treatment were significantly improved if salivary HRP proteolysis was delayed immediately after collection by acidifying the saliva to pH 4.5 followed by a short boiling time period, which neither affected HRP quantification nor biological activity. Affinity chromatography results were checked both by cationic polyacrylamide gel and by capillary electrophoresis. Antifungal activity was found to reside only in the low pH HRP fraction of the immunoadsorbent column, suggesting that it is the histidine-rich family of polypeptides that is responsible for salivary antifungal action.

Salivary anti-candidal assays

Inhibition of Candida albicans blastospore viability by parotid, submandibular-sublingual and whole salivas could not be determined by direct assay of yeast cells in each respective saliva. Determination of antifungal activity could, however, be carried out if saliva was first preincubated with Candida cells and this was immediately followed by removal of saliva and resuspension of yeast cells in nonenriched buffers of pH 5-7 for appropriate incubation periods. To attain accurate reproducible quantitative data, parotid, submandibular-sublingual and whole salivas each required different preincubation times with C. albicans as well as prior acidification and boiling. Acidification was also necessary for optimizing the germ tube assay although, in contrast to blastospore viability, inhibition of blastospore-germ tube conversion could be determined directly in saliva. Salivary antifungal effects on blastospore division were negligible at yeast cell concentrations greater than 10(6) colony-forming units per ml and were found to be independent of pH, whereas salivary inhibition of germ tube formation was significant only at pH 5 in the assay systems employed. The requirement for acidification and an observed enhancement of antifungal activity on aqueous dilution of the saliva suggested that only a fraction of the salivary antifungal components present in saliva were available in the free form to exert their biological activity. These results open up the possibility of investigating salivary antifungal activity in human health and disease.

Differentiation of cytochrome P-450 inducers on the basis of 7-alkoxycoumarin O-dealkylase activities

1. The high-affinity and total activities of 7-methoxycoumarin O-demethylase and of 7-ethoxycoumarin O-deethylase were measured in liver microsomes isolated from rats treated with prototypic inducers belonging to the main classes of microsomal enzyme inducers currently recognized. 2. Each inducer (with the exception of clofibrate which was ineffective) produced a unique induction profile, indicating the possibility of using these two enzymes, each measured at two substrate concentrations, for characterization of the inducing potential of novel xenobiotics. 3. Differences between p,p'-DDT and phenobarbitone in the induction profiles indicate that DDT may not be a pure 'phenobarbitone-type' inducer as has been proposed hitherto.

The use of capillary electrophoresis to identify cationic proteins in human parotid saliva

Eight proteins, HRPs 1, 2, 3, 4, 5 and 6, lysozyme and histatin 6, are the major cationic components of the parotid salivas of normal healthy individuals. Histatins 2 and 4 appear to be further degradation products of the HRPs. Capillary electrophoresis separates all of these eight components, thus allowing future studies to correlate protein concentration with antimicrobial activity in health and disease.

Assessment of antimicrobial treatment of denture stomatitis using an in vivo replica model system: therapeutic efficacy of an oral rinse

Five denture stomatitis patients demonstrating Candida albicans on both maxillary dentures and palates volunteered to test the effects of Peridex oral rinse in treating their oral disease. They used Peridex rinse both as a mouthrinse and as a denture soak for a period of 24 days. Agar replicas of the tissue-fitting surfaces of the maxillary dentures revealed elimination of C. albicans. Significant decreases in palatal inflammation were also noted, although some inflammation was still evident. Several weeks after the termination of Peridex oral rinses, inflammation increased as concentrations of C. albicans on the denture surface returned to pretreatment levels. A marked similarity in the site-specific localization of this yeast species on the denture was noted before and after Peridex rinse treatment.

Comparative study of single layer and conventional closure of uterine incision in cesarean section

Single layer interrupted suture closure of uterine wound incisions represent a viable choice over conventional closure since the operation not only has benefits in case of performance but also possesses a rational basis for the avoidance of ischemia of the wound, infection and hematoma formation. There is a distinct advantage of single interrupted suture closure over conventional closure because there is a substantially higher number of normal hysterograms in this group showing good integrity of the scar in the uterus.

C-nor-9,11-secoestranes as modified estrogens and fertility regulation

The synthesis of C-nor-9,11-secoestradiol (4) has been achieved from 17 beta-acetoxy-11-chloro-3-methoxy-C-nor-9,11-secoestra-1,3,5(10)-tr ien-9-one (1) through a sequence of reactions without affecting the stereochemistry of estradiol-17 beta. Removal of the 9-keto function of 1 by hydrogenolysis and its subsequent treatment with Na/NH3 gives C-nor-9,11-secoestradiol 3-(methyl ether) (3), which has been demethylated under alkaline conditions to furnish C-nor-9,11-secoestradiol (4). Pyridinium chlorochromate oxidation of 3 gives the corresponding 17-ketone 6. Jones' oxidation of 4 to the ketone 5 and reaction of 5 and 6 with lithium acetylide gives corresponding 17 alpha-ethynyl derivatives 7 and 8. Relative binding affinity to estradiol-17 beta receptors and uterotropic, antiuterotrophic, and antiimplantation activities of compounds 3-8 have been studied. The effect of conformational flexibility on ligand-receptor interaction of these compounds is discussed.

A comparison of the inhibition of blastospore viability and germ-tube development in Candida albicans by histidine peptides and ketoconazole

Synthetic homologous peptides of L-histidine, ranging in length from 3 to 64 amino-acid residues, suppressed blastospore viability. Killing activity was dependent upon the peptide molecular size and concentration, and the time of cell exposure to the agent, but was independent of cell concentration in the range 10(5)-10(7) colony-forming units (c.f.u.) per ml. A 25 amino-acid residue polypeptide, similar to the human parotid salivary histidine-rich peptide (HRP-5), also affected yeast viability. Its killing effect was dependent upon the number of c.f.u. in the assay, as well as contact time with the blastospores and the final peptide concentration. HRP-5 inhibition increased with rising pH in the range 5-7.4, in contrast to poly-L-histidine and ketoconazole, which had optimal candidacidal activity at about pH 6. Poly-L-histidine, HRP-5, and ketoconazole each prevented conversion of blastospores to germ tubes, but their rank order of effectiveness varied with the assay selected. In N-acetylglucosamine-supplemented fetal calf serum, poly-L-histidine and HRP-5 were more effective inhibitors than ketoconazole, but the reverse was true in amino-acid-supplemented glucose beef-extract medium. Reduction of both germ-tube numbers and germ-tube size by HRP-5 was concentration-dependent.