Phenylalanine oligopeptides: Circular dichroism studies in solution

The conformations of a series of l-phenylalanine oligomers having the general formula BOC-(Phe)_n-OMe (n = 1–9) were investigated by circular dichroism in a number of solvent systems. These studies indicate that in trifluoroethanol and in hexafluoroisopropanol these oligomers probably form β-associated conformations beginning at the hexamer.     

Small airway morphology and lung function in the transition from normality to chronic airway obstruction.

This study investigated the relationships between pathological changes in small airways (<6 mm perimeter) and lung function in 22 nonasthmatic subjects (20 smokers) undergoing lung resection for peripheral lesions. Preoperative pulmonary function tests revealed airway obstruction [ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC) < 70%] in 12 subjects and normal lung function in 10. When all subjects were considered together, total airway wall thickness was significantly correlated with FEV1/FVC (r2 = 0.25), reactivity to methacholine (r2 = 0.26), and slope of linear regression of FVC against FEV1 values recorded during the methacholine challenge (r2 = 0.56). Loss of peribronchiolar alveolar attachments was significantly associated (r2 = 0.25) with a bronchoconstrictor effect of deep inhalation, as assessed from a maximal-to-partial expiratory flow ratio <1, but not with airway responses to methacholine. No significant correlation was found between airway smooth muscle thickness and lung function measurements. In conclusion, this study suggests that thickening of the airway wall is a major mechanism for airway closure, whereas loss of airway-to-lung interdependence may contribute to the bronchoconstrictor effect of deep inhalation in the transition from normal lung function to airway obstruction in nonasthmatic smokers.     

Deep breaths, methacholine, and airway narrowing in healthy and mild asthmatic subjects.

Deep breaths taken before inhalation of methacholine attenuate the decrease in forced expiratory volume in 1 s and forced vital capacity in healthy but not in asthmatic subjects. We investigated whether this difference also exists by using measurements not preceded by full inflation, i.e., airway conductance, functional residual capacity, as well as flow and residual volume from partial forced expiration. We found that five deep breaths preceding a single dose of methacholine 1) transiently attenuated the decrements in forced expiratory volume in 1 s and forced vital capacity in healthy (n = 8) but not in mild asthmatic (n = 10) subjects and 2) increased the areas under the curve of changes in parameters not preceded by a full inflation over 40 min, during which further deep breaths were prohibited, without significant difference between healthy (n = 6) and mild asthmatic (n = 16) subjects. In conclusion, a series of deep breaths preceding methacholine inhalation significantly enhances bronchoconstrictor response similarly in mild asthmatic and healthy subjects but facilitates bronchodilatation on further full inflation in the latter.     

Survey of an otter<Emphasis Type="Italic">Lutra lutra</Emphasis> population in Southern Italy: site occupancy and influence of sampling season on species detection

In order to assess the current status of the otterLutra lutra Linnaeus, 1758 in Southern Campania (Italy), we surveyed 141 sites for spraints (faeces) in 2001. Fifty-eight sites were surveyed during the winter and in the following summer in order to test, through an estimation-based approach, the influence of sampling season on species detection. Site occupation in the study area was high (69.5%) and possibly underestimated, because the survey was affected by non-detection errors. Our analyses showed that winter surveying markedly underestimated true otter occupancy at the 58 sites (51.7% vs 97.1%), whereas summer surveying was very reliable (91.4%). Rains and floods may have removed spraints during winter, thereby reducing the detection probability to 0.534. These results suggest that otter standard surveys in areas with Mediterranean-type climates should be conducted during summer or periods without prolonged precipitation. Comparing our results with those of the 1985 National survey, we found an occupancy increase from 65.8 to 100%. We could not establish whether this change reflected a population increase or was due to possible non-detection errors that occurred in the 1985 survey. However, the present occupancy substantiates the strategic relevance of the study area for planning the conservation of Italian otters.     

The TRPA1 channel and oral hypoglycemic agents

Diabetes mellitus type 2 (DM2) results from the combination of insulin unresponsiveness in target tissues and the failure of pancreatic β cells to secrete enough insulin.¹ It is a highly prevalent chronic disease that is aggravated with time, leading to major complications, such as cardiovascular disease and peripheral and ocular neuropathies.² Interestingly, therapies to improve glucose homeostasis in diabetic patients usually involve the use of glibenclamide, an oral hypoglycemic drug that blocks ATP-sensitive K⁺ channels (K_ATP),^3,4 forcing β cells to release more insulin to overcome peripheral insulin resistance. However, sulfonylureas are ineffective for long-term treatments and ultimately result in the administration of insulin to control glucose levels.⁵ The mechanisms underlying β-cell failure to respond effectively with glibenclamide after long-term treatments still needs clarification. A recent study demonstrating that this drug activates TRPA1,⁶ a member of the Transient Receptor Potential (TRP) family of ion channels and a functional protein in insulin secreting cells,^7,8 has highlighted a possible role for TRPA1 as a potential mediator of sulfonylurea-induced toxicity.     

Overexpression of ANXA1 in Penile Carcinomas Positive for High-Risk HPVs

The incidence of penile cancer varies between populations but is rare in developed nations. Penile cancer is associated with a number of established risk factors and associated diseases including phimosis with chronic inflammation, human papillomavirus (HPV) infection, poor hygiene and smoking. The objective of this study was to identify genes related to this type of cancer. The detection of HPV was analyzed in 47 penile squamous cell carcinoma samples. HPV DNA was detected in 48.9% of penile squamous cell carcinoma cases. High-risk HPV were present in 42.5% of cases and low-risk HPV were detected in 10.6% of penile squamous cell carcinomas. The RaSH approach identified differential expression of Annexin A1 (ANXA1), p16, RPL6, PBEF1 and KIAA1033 in high-risk HPV positive penile carcinoma; ANXA1 and p16 were overexpressed in penile squamous cells positive for high-risk HPVs compared to normal penile samples by qPCR. ANXA1 and p16 proteins were significantly more expressed in the cells from high-risk HPV-positive penile carcinoma as compared to HPV-negative tumors (p<0.0001) independently of the subtype of the carcinoma. Overexpression of ANXA1 might be mediated by HPV E6 in penile squamous cell carcinoma of patients with high-risk HPVs, suggesting that this gene plays an important role in penile cancer.     

Immunopositivity for Histone MacroH2A1 Isoforms Marks Steatosis-Associated Hepatocellular Carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Prevention and risk reduction are important and the identification of specific biomarkers for early diagnosis of HCC represents an active field of research. Increasing evidence indicates that fat accumulation in the liver, defined as hepatosteatosis, is an independent and strong risk factor for developing an HCC. MacroH2A1, a histone protein generally associated with the repressed regions of chromosomes, is involved in hepatic lipid metabolism and is present in two alternative spliced isoforms, macroH2A1.1 and macroH2A1.2. These isoforms have been shown to predict lung and colon cancer recurrence but to our knowledge, their role in fatty-liver associated HCC has not been investigated previously.

Methods

We examined macroH2A1.1 and macroH2A1.2 protein expression levels in the liver of two murine models of fat-associated HCC, the high fat diet/diethylnistrosamine (DEN) and the phosphatase and tensin homolog (PTEN) liver specific knock-out (KO) mouse, and in human liver samples of subjects with steatosis or HCC, using immunoblotting and immunohistochemistry.

Results

Protein levels for both macroH2A1 isoforms were massively upregulated in HCC, whereas macroH2A1.2 was specifically upregulated in steatosis. In addition, examination of human liver samples showed a significant difference (p<0.01) in number of positive nuclei in HCC (100% of tumor cells positive for either macroH2A1.1 or macroH2A1.2), when compared to steatosis (<2% of hepatocytes positive for either isoform). The steatotic areas flanking the tumors were highly immunopositive for macroH2A1.1 and macroH2A1.2.

Conclusions

These data obtained in mice and humans suggest that both macroH2A1 isoforms may play a role in HCC pathogenesis and moreover may be considered as novel diagnostic markers for human HCC.     

Naphthalene diimide scaffolds with dual reversible and covalent interaction properties towards G-quadruplex

Selective recognition and alkylation of G-quadruplex oligonucleotides has been achieved by substituted naphathalene diimides (NDIs) conjugated to engineered phenol moieties by alkyl-amido spacers with tunable length and conformational mobility. FRET-melting assays, circular dichroism titrations and gel electrophoresis analysis have been carried out to evaluate both reversible stabilization and alkylation of the G-quadruplex. The NDIs conjugated to a quinone methide precursor (NDI-QMP) and a phenol moiety by the shortest alkyl-amido spacer exhibited a planar and fairly rigid geometry (modelled by DFT computation). They were the best irreversible and reversible G-quadruplex binders, respectively. The above NDI-QMP was able to alkylate the telomeric G-quadruplex DNA in the nanomolar range and resulted 100-1000 times more selective on G-quadruplex versus single- and double-stranded oligonucleotides. This compound was also the most cytotoxic against a lung carcinoma cell line.     

Inhibitory effects of glycosaminoglycans on basal and stimulated transforming growth factor-β1 expression in mesangial cells: biochemical and structural considerations

A number of glycosaminoglycan (GAG) species related to heparin, dermatan sulfate (DeS) and chondroitin sulfate were tested for their ability to interfere with the physiological expression and/or pathological overexpression of the TGF-β1 gene. The influence of the molecular weight, molecular weight distribution, degree of sulfation and location of the sulfate groups was examined in an attempt to unveil fine relationships between structure and activity. The nature of the polysaccharide plays a major part, heparins proving able to inhibit both basal and stimulated TGF-β1 gene expression, DeSs being essentially inactive and chondroitin sulfates only inhibiting stimulated TGF-β1 gene expression. Within this frame, the particular physical and chemical properties of some GAGs appear to further modulate TGF-β1 gene response. Judging from our investigation, chondroitin sulfates seem the most promising for potential pharmacological applications in disorders characterized by fibrogenic TGF-β1 overexpression.