Study of the efficacy of 5 ALA-mediated photodynamic therapy on human larynx squamous cell carcinoma (Hep2c) cell line

5-aminolevulanic acid (ALA), a precursor of Protoporphyrin IX, was evaluated as an inducer of photodamage on Hep2c, human larynx squamous cell carcinoma, cell line. Porphyrins are used as active cytotoxic antitumor agents in photodynamic therapy (PDT). The present study evaluates the effects of photodynamic therapy (PDT) with 5-aminolevulinic acid (5-ALA) using human larynx cells as experimental model. Hep2c cell line was irradiated with red light (a diode laser, λ = 635 nm). The influence of different incubation times and concentrations of 5-ALA, different irradiation doses and various combinations of photosensitizer and light doses on the cellular viability of Hep2c cells were studied. The optimal uptake of photosensitizer ALA in Hep-2c cells was investigated by means of spectrometric measurement. Cells viability was determined by means of neutral red assay (NR). It was observed that sensitizer or light doses have no significant effect on cells viability when studied independently. The spectrometric measurements showed that the maximal cellular uptake of 5-ALA occurred after 7 h in vitro incubation. The photocytotoxic assay showed that light dose of 85 J/cm² gives effective PDT outcome for Hep2c cell line incubated with 55 μg/ml of 5-ALA with a conclusion that Hep2c cell line is sensitive to ALA-mediated PDT.     

The isoindolobenzazepine alkaloids

Three Chilean barberries, $\text{Berberis}$$\text{actinacantha}$ Mart. ex Schult., $\text{B}$. $\text{darwinii}$ Hook and [ulbar|B. $\text{valdiviana}$Phil. (Berberidaceae), have yielded several new isoindolobenzazepine and protoberberine alkaloids. Novel isoindolobenzazepines are (±)-13-deoxychilenine ($\text{a}$), pictonamine ($\text{10}$), chileninone ($\text{12}$), (±)-chileniimi ($\text{18}$) and (±)-palmanine ($\text{19}$). Highly oxidized protoberberines of particular interest include (±)-O-methylprechilenine ($\text{6}$) and (±)-prepseudopalmanine ($\text{21}$), together with 13-methoxy-8-oxyberberine ($\text{8}$). Isoindolobenzazepine alkaloids arise biogenetically from the rearrangement of highly oxidized protoberberines.     

Isolation and structure elucidation of three glycosides and a long chain alcohol from Polianthes tuberosa Linn

Three glycosides and a long chain alcohol were isolated from the bulbs of Polianthes tuberosa, these were identified as 3,29-dihydroxystigmast-5-ene-3-O-beta-D-galactopyranoside (1), ethyl beta-D-galactopyranoside (2), ethyl-alpha-D-galactopyranoside (3), and 1-tricosanol (4). The structures were determined by extensive spectroscopic and chemical methods. All four isolated compounds were screened for their cytotoxicity, antibacterial and antifungal activities, none of the compounds showed any significant activity.     

Simple Method for the Preparation of Symmetrical Alkyl and Aryl Disulfides with Alkyl Sulfonyl Halides in Nitrogenous Base

In the present study, the reaction of thiols with alkyl sulfonyl halides was carried out in a nitrogenous base to compare the reactivity of ‐SH with that of ‐OH, which, however, led to the formation of disulfides. The reaction achieved as a result offers the use of an inexpensive reagent, quantitative yields of the product, and simplicity for the formation of the S‐S bond.     

Viability of 4,5-dihydro-1,2,3,4-oxatriazoles reinvestigated

The first procedures to prepare 4-bromo-4-methylpentanal and 4-azido-4-methylpentanal are reported. The latter compound and also the parent 4-azidobutanal do not lead to 4,5-dihydro-1,2,3,4-oxatriazoles by intramolecular 1,3-dipolar cycloaddition, although it was claimed to be so in the literature. The NMR spectroscopic data of such heterocycles reported previously do not agree with those of similar substances and are incompatible with (13)C NMR spectroscopic chemical shifts calculated by quantum chemical methods in the presented work. These calculations show furthermore that the intramolecular cycloaddition of 4-azidobutanals to give the title compounds is strongly endothermic and thus most probably not possible.     

In vivo study of laser irradiation of fractionated drug administration based mechanism for effective photodynamic therapy in rat liver

Up-regulation of stress-activated proteins in cancer cells plays a protective role against photodynamic induced apoptosis. Post photodynamic therapy extracted normal rat liver tissue usually shows a fraction of surviving cells, the photodynamic resistant cells, residing in the necrotic region. To treat these photo-dynamic resistant cells a technique has been proposed based on fractionated drug administration of diluted photosensitizer, keeping the net concentration (5 mg/kg) constant, and subsequently varying drug light interval (DLI). Flourescence measurements were made for the presence of photosensitizer in a tissue. For qualitative analysis both histological and morphological studies were made. Although preliminary aim of this approach was not achieved but there were some interesting observation made i.e. for higher dilution of photosensitizer there was a sharp boundary between necrotic and normal portion of tissue. An increase in the absorption coefficient (α) from 2.7 → 2.9 was observed as photosensitizer was diluted while the corresponding threshold dose (D _th) persistently decreases from (0.10 → 0.02) J/cm² when irradiated with a 635 nm laser fluence of 150 J/cm².     

Cohen-Macaulay modifications of the vertex cover ideal of a graph

We study when the modifications of the Cohen-Macaulay vertex cover ideal of a graph are Cohen-Macaulay.