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Objectives: To examine the efficacy and mechanism of δ- or 5-aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT) on a human hepatocellular carcinoma cell line. Materials and methods: The optimal uptake of photosensitizer ALA in HepG2 (p53 wild) cells was investigated by means of spectrometric measurement. Cell viability was determined by trypan blue exclusion assay. Morphological apoptotic changes in HepG2 cells before and after ALA-mediated PDT were determined by microscopic examination. Detection of apoptotic bodies was examined by DAPI staining. The changes in p53 expression were revealed by the immunostaining method. Results: ALA/protoporphyrin IX (PpIX) was mainly located in the cytoplasm of HepG2 cells. The maximal cellular uptake occurred after 18 h in vitro incubation. The photocytotoxic assay showed that ALA PDT induced 80% killing at 2 mM drug dose and 2 J/cm2 light intensity. Up to 70% of cells showed membrane blebbing and positive DAPI staining, indicating that ALA–PDT-mediated cell death was predominantly via apoptosis. In addition, p53 was upregulated after treatment, implying that p53 might evoke apoptotic cell death. Conclusions: HepG2 cell line is sensitive to ALA-mediated PDT. ALA–PDT induces apoptosis in the HepG2 cell line that may be mediated by a p53-dependent pathway. [ABSTRACT FROM AUTHOR]

The hydrolysis activity of superacids on palm olein, including tungstophosphoric acid and molybdophosphoric acid and their partially ion-exchanged cesium (Cs) salt, were investigated and compared with macroporous cation-exchanged resin and aluminum-incorporated mesoporous molecular sieve. The activities of the superacids supported on the resin and silica were also determined. The reactions were carried out in a stirred batch reactor with continuous steam injection at temperatures from 140 to 180°C. The reaction kinetics, obtained by regression, are first order with respect to TG of the superacids and Cs salts. Of the catalysts studied, the superacids loaded onto cation-exchanged resins were the most active on a weight basis. However, in terms of the turnover number per acid site, the Cs salt of tungstophosphoric acid had 13 times the activity of the cation-exchanged resin. The original superacids had lower activities than the Cs salts in terms of their turnover number. The observations are qualitatively in line with the higher acid strengths of the catalysts, as confirmed by the low activity of the aluminum silicate mesoporous molecular sieve, which is known to have a high concentration of low-to moderate-strength acid sites. The activation energy of the reaction with the Cs salts was ∼49 kJ mol−1. This is rather low as compared to that catalyzed by the cation-exchanged resin. [ABSTRACT FROM AUTHOR]

Hb-H disease is a form of α-thalassemia commonly found in south-east Asia. In this condition, numerous Hb-H bodies are found in erythrocytes using reticulocyte staining preparations. This is the first study addressing the possible interference of Hb-H inclusions in automated reticulocyte counting. In this study, seven Hb-H disease samples were tested. Results obtained by the visual method and the Technicon H*3 automated method agreed relatively well. This was in contrast to the Coulter STKS automated method which generally gave lower results. Furthermore, when the incubation time was extended to 180 min in the Coulter STKS method, two Hb-H disease samples gave results several-fold higher than those obtained using the 60 min incubation time. These discrepant results were likely to have been caused by the analyser using the wrong threshold to separate reticulocytes and mature erythrocytes. High and low interference in Hb-H disease samples was observed in the Coulter STKS automated reticulocyte method. Laboratories should be aware of this potential problem, particularly when samples are from patients of Asian origin. [ABSTRACT FROM AUTHOR]

Hydrolysis of palm oil was studied using four types of commercial H+-exchanged resin with acidity in the region of 5×10−3 eq g−1 but with different pore volumes, specific surface areas, and pore diameters. The reaction was carried out in a stirred batch reactor in the liquid phase with continuous steam injection for up to 14 h. The rate of hydrolysis did not depend on total pore volume and specific surface area but did depend on pore diameter. On exchanging H+ with La3+, Co2+, and Na+, the rate of reaction decreased markedly and was dependent on the degree of exchange, demonstrating that hydrolysis was catalyzed by H+ sites. The activation energy for the hydrolysis of the triglycerides was estimated to be 240 kJ mol−1. A procedure to estimate the rates of the different stages of hydrolysis and hence the individual rate constants of the forward and reverse reactions is described. The procedure yielded reasonable parameters for the reaction at 155°C up to 6 h of reaction time, when about 75 mol% of triglycerides was hydrolyzed. [ABSTRACT FROM AUTHOR]