Tumor Infiltrating Lymphocytes as an Independent Prognostic Factor in Undifferentiated Nasopharyngeal Carcinoma.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is a common type of cancer in Southeast Asia. This cancer usually spreads locally and to nearby lymph nodes. One unique feature of NPC is its many immune cells called tumor-infiltrating lymphocytes (TILs). Recent studies have suggested that TILs in many types of cancer can indicate a better prognosis. However, the role of TILs in NPC is still a matter of debate. Further research is necessary to determine whether TILs can be used as a prognostic factor of NPC's outcome. METHOD: A retrospective cohort study was conducted at Sardjito Hospital to examine the records and pathological sections of patients treated for the undifferentiated subtype of NPC. Two pathologists analyzed the presence of TILs using HE-stained slides. TILs were evaluated in stromal compartments, and their association with clinicopathological variables was analyzed using the Chi-square and Fisher exact tests. The study compared overall survival in tumor patients with varying TIL levels using Kaplan-Meier survival curves and the log-rank test. A Cox regression model was used for univariate and multivariate analyses to test the significance of different factors. RESULT: Out of the total 61 subjects, 16 (26.2%) had high stromal TILs (≥ 70%), and 45 (73.8%) had low stromal TILs (<70%). The subjects' sex, age, and tumor stage did not affect the OS. However, high stromal TILs (≥ 70%) showed a significant association with a longer OS (log-rank test p = 0.006, HR 0.37, 95% CI 0.17-0.79, log-rank p = 0.006). Moreover, multivariate analysis confirmed that TILs were an independent prognostic indicator for OS (aHR 0.015). CONCLUSION: TILs correlate positively with overall survival in the undifferentiated NPC subtype and are an independent prognostic indicator.

Pressure and temperature stability of 5-methyltetrahydrofolic acid: a kinetic study.

Detailed kinetic studies of [6S] and [6RS] 5-methyltetrahydrofolic acid (5-CH3-H4folate) degradation during thermal (from 60 to 90 degrees C) and high pressure/thermal (from 30 to 45 degrees C; from 200 to 700 MPa) treatments were carried out. The results confirmed that the temperature and pressure induced degradation kinetics of [6S] 5-CH3-H4folate were identical (within 95% confidence interval) with those of [6RS] 5-CH3-H4folate. Under equal processing conditions, the estimated degradation rate constants (k), activation energy (E(a)), and activation volume (V(a)) values of [6S] and [6RS] 5-CH3-H4folate were the same (95% confidence interval). The modified thermodynamic model proposed by Nguyen and co-workers (J. Agric. Food Chem. 2003, 51, 3352-3357) to describe the pressure and temperature dependence of the rate constant for folate degradation was reevaluated.

Implications of beta-mercaptoethanol in relation to folate stability and to determination of folate degradation kinetics during processing: a case study on [6S]-5-methyltetrahydrofolic acid.

The effect of beta-mercaptoethanol (0-2%) addition to thermally and/or pressure-treated samples on [6S]-5-methyltetrahydrofolate was studied. Degradation of [6S]-5-methyltetrahydrofolate during both thermal and pressure treatments was mainly caused by oxidation, and the oxidized folates could be partly/completely reduced by beta-mercaptoethanol. The addition of beta-mercaptoethanol (2%) to the thermally and pressure-treated samples overestimated the "actual" stability of [6S]-5-methyltetrahydrofolate and misled the obtained kinetic information.

Kinetic study on the changes in the susceptibility of egg white proteins to enzymatic hydrolysis induced by heat and high hydrostatic pressure pretreatment.

A kinetic study was conducted on the effect of heat pretreatment in the temperature range of 50-85 degrees C at atmospheric pressure and of high hydrostatic pressure pretreatment (100-700 MPa) at four temperatures (10, 25, 40, and 60 degrees C) on the susceptibility of egg white solutions (10% v/v, pH 7.6) to subsequent enzymatic hydrolysis by a mixture of trypsin and alpha-chymotrypsin at 37 degrees C and pH 8.0. Both heat pretreatment at atmospheric pressure and high-pressure pretreatment resulted in an increase in degree of hydrolysis (DH) after 10 min of enzymatic reaction (DH10) of egg white solutions, as measured using the pH-stat method, which could be described by a fractional conversion model (based on an apparent first-order reaction kinetic model). The temperature dependence of the corresponding rate constants could be described by the Arrhenius equation. At elevated pressure, a negative apparent activation energy was obtained, implying an antagonistic effect of pressure and temperature. The pressure dependence of the rate constants could be described by the Eyring equation, and negative activation volumes were observed, which demonstrates the positive effect of pressure on the susceptibility of egg white solutions to subsequent enzymatic hydrolysis.

Heat-induced changes in the susceptibility of egg white proteins to enzymatic hydrolysis: a kinetic study.

A kinetic study was conducted on the effect of heating in the temperature range of 50-92 degrees C, on the susceptibility of ovalbumin and albumen solutions to enzymatic hydrolysis by a mixture of trypsin and alpha-chymotrypsin at 37 degrees C and pH 8.0. Heat treatment resulted in an increase in degree of hydrolysis after 10 min of enzymatic reaction of both ovalbumin and albumen, as measured using the pH-stat method. The time-dependent change in the susceptibility to enzymatic hydrolysis after heat treatment was described by a fractional conversion model (based on an apparent first-order reaction kinetic model). Different end levels of degree of hydrolysis were obtained after heating for a long time at different temperatures, which suggests that the final degree of unfolding of the protein is temperature dependent.

Partial purification, characterization, and thermal and high-pressure inactivation of pectin methylesterase from carrots (Daucus carrota L.).

Pectin methylesterase (PME) from carrots (Daucus carrota L.) was extracted and purified by affinity chromatography on a CNBr-Sepharose 4B-PME inhibitor column. A single protein and PME activity peak was obtained. A biochemical characterization in terms of molar mass (MM), isoelectric points (pI), and kinetic parameters of carrot PME was performed. In a second step, the thermal and high-pressure stability of the enzyme was studied. Isothermal and combined isothermal-isobaric inactivation of purified carrot PME could be described by a fractional-conversion model.

Comparative study of the inactivation kinetics of pectinmethylesterase in tomato juice and purified form.

Pectinmethylesterase (PME) extracted from tomato fruit was purified by affinity chromatography. A single peak of PME activity was observed, presenting a molar mass of 33.6 kDa, an isoelectric point higher than 9.3, and an optimal temperature and pH for activity of 55 degrees C and 8.0, respectively. The processing stability of purified tomato PME in buffer solution was compared to PME stability in tomato juice. In both media, thermal inactivation of PME presented first-order inactivation kinetics, PME in tomato juice being more heat-labile than purified PME. Regarding high-pressure treatment, tomato PME showed to be very pressure-resistant, revealing an outspoken antagonistic effect of temperature and pressure. To avoid cloud loss in tomato juice, a time-temperature treatment of 1 min at 76.5 degrees C was calculated in order to have a residual PME activity of 1 x 10(-)(4) U/mL.