Iridoid and bisiridoid glycosides from Globularia cordifolia

From the methanolic extract of the underground parts of Globularia cordifolia, a new iridoid glycoside, 5-hydroxydavisioside (1) and a new bisiridoid glycoside, globuloside C (2) were isolated along with six known iridoid glycosides, aucubin, melampyroside, monomelittoside, globularifolin, alpinoside and asperuloside. The structures of the isolates were established by 1D and 2D NMR spectroscopy in combination with IR, UV and MS analyses.     

Reaction conditions for laccase catalyzed polymerization of catechol

Poly(catechol) was synthesized in batch runs with laccase from Trametes versicolor (ATCC 200801). The polymerization reaction was conducted in a closed, temperature controlled system containing acetone and sodium acetate buffer for pH control. The effects of the solvent mixture, monomer (catechol), enzyme, medium pH and temperature on the polymerization rate were investigated with respect to initial reaction conditions and depletion rate of dissolved oxygen in the medium. Maximum initial reaction rate was attained with 10% (v/v) acetone-sodium acetate buffer at pH 5.0, 25 degrees C, 0.02 U/ml enzyme and 250 mg/l initial catechol and 10 mg/l dissolved oxygen. A general saturation enzyme kinetics response was observed for catechol substrate. Temperature rise supported the rate increase up to 45 degrees C, after which the rate tended to be stable due to a drop in dissolved oxygen concentration as well as enzyme instability.     

Gender influence on jejunal migrating motor complex

The role of gender and the menstrual cycle in small bowel motility has not been clearly elucidated. Jejunal motility was recorded with a nasojejunal catheter incorporating five solid-state pressure transducers in ambulatory menstruating women and men of comparable age over 24 h. All women were studied twice, in the early follicular (early-F) and midluteal (mid-L) phases of the menstrual cycle, verified by determining serum levels of gonadal steroids and gonadotropins. The propagation velocity of phase III was slow and the contraction amplitude was high in both menstrual cycle phases compared with men, and these parameters were correlated with serum estrogen levels in the mid-L phase. In the early-F phase, migrating motor complex (MMC) cycle duration during sleep was long compared with other groups and positively correlated with estrogen concentrations, whereas in the mid-L phase MMC cycle duration during sleep was negatively correlated with serum progesterone levels. In all groups, the frequency of phase III contractions was low and the intercontractile interval measured from pressure peak to peak was long during sleep compared with the awake state. Postprandial motility did not display gender difference in any parameter examined. The results demonstrate that the majority of patterns of motility are similar in menstruating women and men, whereas certain aspects of the MMC, most conspicuously propagation velocity and phase III contraction amplitude, differ. We have also documented circadian variation of phase III contraction frequency in both women and men.     

Keratinase of Doratomyces microsporus

 The fungus Doratomyces microsporus produced an extracellular keratinase during submerged aerobic cultivation in a medium containing a protein inducer for enzyme synthesis. The keratinase was purified to homogeneity using hydrophobic interaction chromatography followed by gel chromatography. The molecular weight was estimated to be 33 kDa (from SDS-PAGE analysis) or 30 kDa (by gel chromatography), suggesting a monomeric structure. The isoelectric point of the enzyme was determined to be around 9. The optimal pH and temperature for keratinolytic activity were pH 8–9 and 50 °C, respectively. The serine protease inhibitor PMSF totally inhibited the keratinase. The enzyme was not glycosylated. It was capable of hydrolysing different keratinous materials as well as some non-keratinous proteins. Hydrolysis of some synthetic substrates, specific for known proteinases, suggested that the keratinase of D. microsporus is close to proteinase K. Received: 9 July 1999 / Received revision: 13 September 1999 / Accepted: 17 September 1999     

Endothelin-1-induced PMN infiltration and mucosal dysfunction in the rat small intestine

The objectives of this study were to characterize the effects of endothelin (ET)-1 on intestinal mucosal parameters and to assess the contribution of polymorphonuclear leukocytes (PMNs), intercellular adhesion molecule-1 (ICAM-1), and a platelet-activating factor (PAF) to the mucosal dysfunction induced by ET-1. Different concentrations of ET-1 (100, 200, and 400 pmol/kg) were infused into the superior mesenteric artery for 10 min, and tissue samples were obtained 30 min after terminating the infusion. ET-1 administration significantly elevated tissue myeloperoxidase activity, plasma carbonyl content, and tissue chemiluminescence intensity, indicating that ET-1 produces PMN infiltration and oxidant stress. Blood-to-lumen clearance of (51)Cr-EDTA significantly increased after ET-1 infusion (400 pmol/kg). Monoclonal antibodies against ICAM-1 (1A29, 2 mg/kg), antineutrophil serum, and PAF antagonist (WEB-2086, 10 mg/kg) attenuated the mucosal barrier dysfunction induced by ET-1. Overall, our data indicate that ET-1 causes PMN accumulation, oxidant stress, and mucosal dysfunction in the rat small intestine and that ET-1-induced mucosal dysfunction involves a mechanism that includes a role for PMNs, ICAM-1, and PAF.     

The influence of intracerebroventricular administration of (+/-) propranolol and (+/-) verapamil on experimental myocardial ischemia and necrosis in rats

In albino rats, infarctoid myocardial lesions were produced by intraperitoneal (i.p.) administration of isoproterenol (75 mg/kg, during 3 days). In other groups, the descending anterior left coronary artery was ligated. In both experimental settings, the intracerebroventricular (i.c.v.) administration of (+/-) propranolol (100-200-300 microg/animal/day, during 7 days) or (+/-) verapamil (40-80-160 microg/animal/day, during 7 days) afforded a significant protection (with the exception of the lowest dose) on the investigated parameters: arrhythmias, ischemic zone (in coronary ligated rats), lactate dehydrogenase and aspartate aminotransferase activity of the serum, focal necrosis (in isoproterenol treated rats). This protective activity is lower than that afforded by i.p. administered (+/-) propranolol (5 mg/kg, during seven days) or (+/-) verapamil (5 mg/kg, during seven days). From these data it may be concluded that (+/-) propranolol and (+/-) verapamil have a protective action on the experimental myocardial ischemia and necrosis in rats, not only when the drugs come in direct contact with the heart, but also acting upon the central nervous system.     

Proteus syndrome: clinical and surgical aspects

The authors report a new case of Proteus syndrome with delayed diagnosis and they discuss the place of surgery in this syndrome.     

Self-organization and competition in the immune response to cancer invasion: a phase-orientated computational model of oncogenesis

Motivation: Recent studies indicate that fractal dimensionscan uncover aspects of cellular dynamics prior to pathological manifestation. In this respect we are interested in buildinga computational model of oncogenesis able to generate patternswith the same fractal dimension spectrum as the in vivo tumor. Results: A new theoretical model incorporating a systemic viewof oncogenesis in a computational model was proposed. Thetumor growth is viewed as competition for resources betweenthe two self-organizing subsystems: the neoplastic and theimmune. Numerical simulations revealed that tumor escape canbe uncovered in some earlier stage of the immune-system–tumorinteraction using multifractal measures. The described computationalmodel is able to simulate also the case of immune, surgical,chemical and radiotherapeutical treatment, as well as theireffects. Availability: The software used is available on request fromthe authors. Contact: Sorinel Oprisan, University of New Orleans, Department of Psychology, New Orleans, LA 70148, USA. soprisan{at}uno.edu Received on July 6, 1999 ; revised on September 15, 1999 ; accepted on September 17, 1999     

Molecular analysis of 16 Turkish families with DHPR deficiency using denaturing gradient gel electrophoresis (DGGE)

Dihydropteridine reductase (DHPR) catalyses the conversion of quinonoid dihydrobiopterin (qBH2) to tetrahydrobiopterin (BH4), which serves as the obligatory cofactor for the aromatic amino acid hydroxylases. DHPR deficiency, caused by mutations in the QDPR gene, results in hyperphenylalaninemia and deficiency of various neurotransmitters in the central nervous system, with severe neurological symptoms as a consequence. We have studied, at the clinical and molecular levels, 17 patients belonging to 16 Turkish families with DHPR deficiency. The patients were detected at neonatal screening for hyperphenylalaninemia or upon the development of neurological symptoms. To identify the disease causing molecular defects, we developed a sensitive screening method that rapidly scans the entire open reading frame and all splice sites of the QDPR gene. This method combines PCR amplification and "GC-clamping" of each of the seven exonic regions of QDPR, resolution of mutations by denaturing gradient gel electrophoresis (DGGE), and identification of mutations by direct sequence analysis. A total of ten different mutations were identified, of which three are known (G23D, Y150C, R221X) and the remaining are novel (G17R, G18D, W35fs, Q66R, W90X, S97fs and G149R). Six of these mutations are missense variants, two are nonsense mutations, and two are frameshift mutations. All patients had homoallelic genotypes, which allowed the establishment of genotype-phenotype associations. Our findings suggest that DGGE is a fast and efficient method for detection of mutations in the QDPR gene, which may be useful for confirmatory DNA-based diagnosis, genetic counselling and prenatal diagnosis in DHPR deficiency.