Modelling the population dynamics of <Emphasis Type="Italic">Daphnia obtusa</Emphasis> (Kurz) in Lake Orta (N. Italy) under pre- and post-liming conditions

A mathematical matrix model was formulated to investigate the response of Daphnia obtusa population dynamics to the changes in the water chemistry of Lake Orta before and after the liming operation. Model parameters were estimated from experimental laboratory data. Model analysis showed that water chemistry changes induced by liming affected mainly egg survival and predicted the highest population growth at pH␣6. Whereas increased egg mortality heavily inhibits population growth rate, the model still predicts a long term tendency of the population to increase in number. However, both before and after the liming operation due to high food availability in the laboratory, egg production was higher under all experimental conditions than in the field. When food limitation is accounted for and more realistic, field based estimates of egg production are used, the model predicts the extinction of D. obtusa population in the lake. This suggests that the effects of water chemistry changes on egg mortality had a critical role in the disappearance of D. obtusa from Lake Orta and may even adequately explain the extinction of this population.     

Licorice: A possible anti-inflammatory and anti-ulcer drug

The purpose of this investigation was to study the anti-inflammatory activities of both glycerrhitinic acid (GA) and the aqueous licorice extract (ALE) in comparison with diclofenac sodium (DS) (10 mg/kg), using the carrageenan-induced paw edema model in male albino rats. In addition, the anti-ulcer activities of ALE, famotidine (FT), and a combination of ALE and FT using indomethacin-induced ulceration technique in rat stomach were investigated. Conventional DS tablets containing GA, as well as DS chewable tablets containing either GA or ALE with different tastes were prepared. Also, rapidly disintegrating FT tablets were prepared using direct compression and camphor sublimation methods. ALE or GA produced significant anti-inflammatory activity similar to DS, and when taken concomitantly, there is no possible antagonism. The anti-ulcer activity of licorice was found to be similar to that of FT in indomethacin-induced ulceration technique in rat stomach. Combination therapy of both FT and licorice showed higher anti-ulcer activity than either of them alone. Generally, tablets containing the crosslinked sodium carboxymethyl cellulose (AcDisol) showed more rapidly disintegrating effect than those including Sodium starch glycolate (Primojel). The oral disintegration was very rapid for all the tested formulations. Also, the amount of FT absorbed from the oral cavity was nearly 9 from 10 mg theoretically present in each formula. It could be concluded that both GA and ALE have anti-inflammatory activity comparable with DS. It may be recommended to add ALE to either FT or diclofinac for more effective anti-inflammatory or anti-ulcer formulations, respectively.     

Synthesis and antimicrobial activity of some new N-glycosides of 2-thioxo-4-thiazolidinone derivatives

5-Arylidene-2-thioxo-4-thiazolidinones 3a-f react with each of 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl and α-d-galactopyranosyl bromides 4a,b in acetone in the presence of aqueous potassium hydroxide at room temperature to afford N-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl) or N-(2,3,4,6-tetra-O-acetyl-β-d-galactopyranosyl) 2-thioxo-4-thiazolidinone derivatives 5a-f. Similarly, the reaction of 5-cycloalkylidene-2-thioxo-4-thiazolidinones 7a,b with 4a gave the corresponding N-glucosides 8a,b. Also, 5-pyrazolidene rhodanines 10a-e react with 4a to afford the new N-glucosides 11a-e. Treatment of compounds 15 and 16 with 4a in the presence of few drops of triethylamine or in KOH solution accomplished the mono- and bis-nucleosides 17 and 18, respectively. Some selected products were tested for their antimicrobial activities.     

'Genomemark': detecting word periodicity in biological sequences

Identifying and predicting the structural characteristics of novel repeats throughout the genome can lend insight into biological function. Specific repeats are believed to have biological significance as a function of their distribution patterns. We have developed 'GenomeMark,' a computer program that detects and statistically analyzes candidate repeats. Specifically, 'GenomeMark' identifies the periodic distribution of unique words, calculating their chi2 and Z-score values. Using 'GenomeMark,' we identified novel sequence words present in tandem throughout genomes. We found that these sequences have remarkable spacer sequence distributions and many were genome specific, validating the genome signature theory. Further analysis confirmed that many of these sequences have a specific biological function. The program is available from the authors upon request and is freely available for non-commercial and academic entities.     

Identification of oncofetal antigen/immature laminin receptor protein epitopes that activate BALB/c mouse OFA/iLRP-specific effector and regulatory T cell clones

During tumor development in mice and humans, oncofetal Ag/immature laminin receptor (OFA/iLRP)-specific Th1, CTL, and IL-10-secreting T (Ts) cells are induced. The presence of too many Ts or too few effector T cells appears to predict a poor prognosis. We established clones of OFA/iLRP-specific splenic Th1, CTL, and Ts cells from the OFA/iLRP+ MCA1315 fibrosarcoma-bearing BALB/c mice or from BALB/c mice vaccinated with 1 or 10 microg of rOFA/iLRP. The MCA1315 tumor cell-reactive T cell clones were characterized as to surface Ag phenotype, cytokine secretion profile, and specificity for OFA/iLRP presented by syngeneic splenic APC. OFA/iLRP-specific Th1 and Ts clones were established from all mice. OFA/iLRP-specific CTL could be established from all mice except for mice immunized with 10 microg of rOFA/iLRP. Analysis of the proliferation profile of the OFA/iLRP-specific clones to overlapping OFA/iLRP 12-mer peptides that spanned the OFA/iLRP protein sequence defined the epitopes to which the T cell clones responded. There was a similar spatial distribution of the epitopes to which the two types of CD8 T cell clones responded. The nonapeptide epitopes of the Ts clones were located between aa 36 and 147 of OFA/iLRP, while the epitopes of the CTL clones were located between aa 52 and 163. Even though the CTL and Ts epitopes shared part of the protein, all of the CD8 CTL epitopes were distinct and separable from those of CD8 Ts cells.     

Urotensin-II receptor blockade with SB-611812 attenuates cardiac remodeling in experimental ischemic heart disease

It is now well established that urotensin-II (UII) levels are increased in several cardiovascular diseases. We previously demonstrated that UII and the UII receptor (UT) protein levels are significantly increased in the hearts of both humans and rats with congestive heart failure (CHF). We have also recently demonstrated that UII blockade, with a selective UII antagonist, improves heart function in a rat model of ischemic CHF. Here, we evaluated the attenuation of cardiac remodeling associated with UII antagonism in the same rat model of ischemic CHF. Animals were administered a specific UT receptor antagonist, SB-611812 (30 mg/kg/day, gavage), or vehicle 30 min prior to coronary artery ligation followed by daily treatment for 8 weeks. Myocardial interstitial fibrosis was analyzed by Masson's trichrome and picrosirius red staining. RT-PCR analysis was utilized for mRNA expression studies. We used Western blotting to assess levels of collagen types I and III. Mitogenic activity of UII on cultured neonatal cardiac fibroblasts was also evaluated. Following coronary ligation, SB-611812 significantly attenuated both myocardial and endocardial interstitial fibrosis, and reduced collagen type I:III ratio (P<0.01). UII induced proliferation of cardiac fibroblasts and this mitogenic effect was significantly inhibited with 1 microM of SB-611218 (P<0.05). We demonstrate here that selective blockade of UT reduces diastolic dysfunction by decreasing myocardial fibrosis post-coronary ligation in vivo, and inhibits UII-mediated fibroblast proliferation in vitro.