A baseline tool for predicting response to peginterferon alfa-2a in HBeAg-positive patients with chronic hepatitis B.

BACKGROUND: Peginterferon induces off-treatment responses in approximately one-third of patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B. AIM: To develop an easy-to-use baseline prediction score to identify hepatitis B virus (HBV) genotype B-/C-infected HBeAg-positive Asian patients likely to respond to peginterferon alfa-2a. METHODS: Generalised additive models, multiple logistic regression (MLR) analysis and internal validation methods were applied to data from 647 HBeAg-positive patients from China, Hong Kong and Taiwan to develop a scoring system to predict response 24 weeks after completing a 48-week course of peginterferon alfa-2a. RESULTS: Five baseline factors (age, sex, alanine aminotransferase ratio, hepatitis B surface antigen (HBsAg) level and HBV DNA level) were retained in the final MLR for HBeAg seroconversion and used to develop a scoring system from 0 to 7. Among patients with scores of 0-1, 2-3, 4 or ≥5, HBeAg seroconversion was achieved in 6.4% (6/94), 23.0% (61/265), 36.4% (67/184) and 54.8% (57/104), respectively, and a combined response (HBeAg seroconversion plus HBV DNA <2000 IU/mL) in 5.3% (5/94), 12.8% (34/265), 25.0% (46/184) and 36.5% (38/104), respectively. Among patients with scores of 0-1, 2-3, 4 or ≥5, 57.0% (53/93), 12.3% (31/253), 3.4% (6/178) and 1.0% (1/100) had HBsAg ≥20 000 IU/mL at treatment Week 12; only 3/91 (3.3%) with HBsAg ≥20 000 IU/mL experienced a combined response at 24 weeks post-treatment (negative predictive value = 97% [88/91]). CONCLUSION: A pre-treatment scoring system using readily available baseline characteristics identifies HBeAg-positive Asian patients likely to experience sustained HBeAg seroconversion after treatment with peginterferon alfa-2a.

The Effect of Ascorbic Acid on Mancozeb-Induced Toxicity in Rat Thymocytes.

Mancozeb, as a dithiocarbamate fungicide, has been found to exhibit toxicological manifestations in different cells, mainly by generation of free radicals which may alter antioxidant defence systems in cells. The effect of mancozeb on the cells of a primary lymphoid organ has not been studied. In the present study, the effects of mancozeb (0.2, 2 and 5 µg/ml) or mancozeb+ascorbic acid (100 µg/ml), or ascorbic acid alone or control medium alone on the levels of cell viability, apoptosis, intracellular reactive oxygen species production (ROS), mitochondrial membrane potential (MMP) and ATP levels in rat thymocytes were examined in vitro. Cells treated with mancozeb displayed a concentration-dependent increase of hypodiploid cells and ROS production followed by markedly decreased viability of the cells, MMP and ATP levels. Application of ascorbic acid significantly reduced cytotoxicity in cell cultures treated with 0.2 and 2 µg/ml of mancozeb, together with significantly decreased ROS levels and increased MMP and ATP levels. In cells treated with 5 µg/ml of mancozeb, ascorbic acid failed to reduce toxicity while simultaneously increasing the apoptosis rate of thymocytes. These results suggest that ROS plays a significant role in mancozeb-induced toxicity, through alteration of mitochondrial function. Ascorbic acid administration reduced the toxicity rate in cells treated with lower mancozeb concentrations, while it may have the ability to shift cells from necrosis to apoptosis in the presence of highest mancozeb concentrations.

Protective role of vitamin C in diazepam-induced apoptosis in rat thymocytes.

Diazepam, a peripheral-type benzodiazepine receptor ligand, is widely used as a therapeutic agent. On the other hand, peripheral-type benzodiazepines have been shown to induce apoptosis in different immune cell types. In this study, we examined the possible protective role of vitamin C in diazepam-induced apoptosis and evaluated the cellular content of glutathione during this process. Rat thymocytes were incubated for 24 hours with diazepam and increasing concentrations of vitamin C or with diazepam alone. The exposure to diazepam resulted in an increase in apoptotic cell death and decrease in glutathione content in rat thymocytes. Vitamin C was effective in ameliorating the effect of diazepam in rat thymocytes by decreasing the proportion of apoptotic cells and increasing the cellular content of glutathione. These results suggest that vitamin C reduced the diazepam-induced apoptosis in rat thymocytes by restoring the cellular content of glutathione, which may be useful in preventing the diazepam-induced immunosupression (Tab. 1, Fig. 1, Ref. 31).

Circulating nucleic acids in type 1 diabetes may modulate the thymocyte turnover rate.

The autoimmunity of type 1 diabetes is associated with T-cell hyperactivity. Current study was designed to examine the effect of circulating ribonucleic acids (RNAs), isolated from type 1 diabetic patients on proliferative, apoptotic and inflammatory potential of rat thymocytes. Rat thymocytes were assayed for proliferating nuclear cell antigen (PCNA), Bcl-2, Bax and NF-κB level, using the flow cytometric and fluorometric assays. Cells were allocated into groups, treated with RNAs purified from plasma of juvenile diabetics, adult type 1 diabetic patients, control healthy children, healthy adult persons, nucleic acids and polynucleotide standards (RNA, polyC, PolyA, PolyIC, and CpG). The upregulation of PCNA and Bcl-2 protein and downregulation of Bax protein and NF-κB was shown when the thymocytes where incubated with RNA purified from plasma of juvenile type 1 diabetic patients. The dysregulation of inflammatory cascade and central tolerance may be a defect in autoimmune diseases related to innate immunity leading to corresponding alteration in adaptive immune response.

The role of ascorbic acid and monosodium glutamate in thymocyte apoptosis.

The studies on experimental animals have confirmed toxic effect of monosodium glutamate in different organs, mainly manifested by increased oxidative stress and cytotoxicity, strongly correlated with numerous diseases. Continuous intake of this flavor enhancer in modern nutrition also resulted with toxic effects on human health, known as Chinese restaurant syndrome. The reference data about influence of monosodium glutamate on the cells of the immune system or primary immune organs and possible protective effects of specific antioxidants are still largely unknown. This review summarizes recently known facts about the role of monosodium glutamate in the cells of the immune system, especially in thymocytes. Also, in this review many new data on positive effects of ascorbic acid on immune system and the mechanisms of its protective influence on thymocytes are discussed (Tab. 1, Ref. 52).

Ascorbic acid modulates monosodium glutamate induced cytotoxicity in rat thymus.

BACKGROUND: Monosodium glutamate (MSG) is a commonly used flavor enhancer in modern nutrition. It has been shown that administration of MSG induces toxic effects in various regions of brain, thymus, liver and kidney. Also, it is well-documented that Vitamin C (ascorbic acid) has a protective role in MSG-induced cytotoxicity in rat liver, kidney and various brain regions, but has not been studied in thymus. OBJECTIVES: In the present study, we examined the possible protective role of Vitamin C in MSG-induced cytotoxicity in adult (Kindly indicate the strain of rat) rat thymus. MATERIAL AND METHODS: MSG was administrated intraperitoneally (4 mg/g of body weight), with or without Vitamin C (500 mg/kg of body weight), for six consecutive days. Animals were sacrificed at 1st, 7th and 14th day of last MSG dose. RESULTS: This study demonstrates that MSG administration in animals significantly decreases cell viability with significant down-regulation of Bcl-2 protein, while Bax protein expression was not significantly changed in rat thymocytes. Vitamin C was effective in ameliorating the effect of MSG in rat thymocytes by increasing the proportion of viable cells and up-regulating the expression of Bcl-2 protein in rat thymocytes. CONCLUSION: These results suggest that the treatment with Vitamin C may prevent the MSG-induced cytotoxicity in rat thymocytes by up-regulating Bcl-2 protein expression resulting in a change in Bcl-2/Bax protein ratio (Tab. 1, Fig. 1, Ref. 32). Full Text (Free, PDF) www.bmj.sk.

Low-dose cyclosporine A therapy increases the regulatory T cell population in patients with atopic dermatitis.

BACKGROUND: Atopic dermatitis (AD) is a T cell dependent chronic relapsing inflammatory skin disorder successfully treated with cyclosporine A (CsA). Clinical observations indicate that even low-dose CsA therapy is successful in severely affected AD patients. We studied the impact of low-dose CsA therapy on the ability of T helper cells to be activated, and examined whether regulatory T (Treg) cells are increased in these patients. METHODS: Peripheral T cells were activated in a whole blood sample and interleukin-2 producing cells were measured by intracellular cytokine staining. Regulatory T cells were analyzed by intracellular FoxP3 staining. Regulatory T cells (CD4(+)CD25(+)CD127(low)) and effector T cells (CD4(+)CD25(-)CD127(+)) were sorted by flow cytometry and used for suppression assays. RESULTS: A group of AD patients treated with low-dose CsA had a significantly larger Treg cell population than a healthy control subject group. In individual patients, onset of low-dose CsA therapy reduced the ability of T cells to be activated to 42 +/- 18% (P < 0.005) and significantly increased Treg cells, both in absolute numbers (1.6-fold change) and frequencies (1.7-fold change). Treg cells from AD patients showed similar suppressive capacities as Treg cells from healthy donors. Furthermore, Treg cells from AD patients had skin homing properties. CONCLUSION: Our results indicate that the therapeutic effect of low-dose CsA therapy in AD patients might be not only mediated by the inhibition of T cell hyperactivity but also by an increased population of Treg cells.

Possible impact of impaired double-stranded RNA degradation and nitrosative stress on immuno-inflammatory cascade in type 2 diabetes.

The immune response can be triggered by molecules derived from microorganisms (PAMP) or from molecules derived from damaged or dead host cells, known as the damage-associated molecular-pattern molecules (DAMP). Their immune effects are accompanied by altered redox environment. The level of stable end products of nitric oxide (NO)- plasma nitrate and nitrite (NOx), carbonyl groups (PCO) and nitrotyrosine (NTY), in relation to the metabolism of dsRNAs (poly I:C and poly A:U) and xanthine oxidase (XO activity), in plasma of type2 diabetic patients was determined. Thirty-six patients with type 2 diabetes (age group 34-66 years, 19 male and 17 female) were allocated to the study. Diabetic patients had a significantly higher level of plasma NOx products, NTY and PCO, fructosamine (FA) and XO activity indicating about altered redox environment. The concentration of circulating ribonucleic acids (CNAs) was significantly higher in type 2 diabetic patients, which was accompanied by a significantly decreased activity of RNase against double stranded RNA forms (poly I:C and poly A:U), compared to control samples. To determine whether CNAs, as possible DAMP molecules, are capable of exerting effect on inflammatory and host antiviral response, the effect of isolated CNAs on NF-kappaB, Bcl-2, Bax, MDA-5 and IRF-3 regulation was evaluated in culture of fresh isolated thymocytes. Circulating nucleic acids isolated from type 2 diabetic patients were able to upregulate NF-kappaB more than control RNA samples. In the same experimental conditions the mild Bcl-2 upregulation, followed by the marked Bax upregulation, was demonstrated. Since the Bcl-2/Bax ratio was lower in type 2 diabetic samples, obtained results may implicate that CNAs may exert proapoptotic response in type 2 diabetes. The CNAs isolated from diabetic patients were able to downregulate MDA-5 and IRF-3, very important subjects of the surveillance and cellular anti-viral response. The major findings of the present study are that impaired dsRNA metabolism may lead to increased level of different sized RNAs in type 2 diabetic patients. Acting as possible DAMP molecules, they may contribute to higher susceptibility of immune cells to inflammatory cascade via NF-kappaB activation, and possible MDA-5/IRF-3 axis downregulation, what may have an influence on further ineffective response against different pathogens.

TOM-independent complex formation of Bax and Bak in mammalian mitochondria during TNFalpha-induced apoptosis.

The Bcl-2 family proteins Bax and Bak are activated in response to many apoptotic stimuli. As a consequence of activation, Bax and Bak oligomerize and permeabilize the outer mitochondrial membrane to permit the release of apoptosis-inducing factors. It still remains unclear whether these proteins require components of the mitochondrial protein import machinery for their function at the mitochondria. Here, we addressed this question by using inducible RNA interference for the study of protein import in mammalian mitochondria. After induction of apoptosis, we could not detect any impact of the absence of Tom22, Tom70, Tom40, Sam50 or metaxins on the translocation of Bax and formation of Bax and Bak complexes in mitochondria. In in vitro import studies, loss of these import and assembly proteins had no or only slight effect on the formation of complexes by radiolabeled Bax and Bak. We conclude that the import and assembly machineries of mammalian mitochondria have no impact on the translocation and complex assembly of Bax and Bak upon apoptosis induction.

Effect of monosodium glutamate on apoptosis and Bcl-2/Bax protein level in rat thymocyte culture.

Monosodium glutamate (MSG), the sodium salt of glutamate, is commonly used as a flavor enhancer in modern nutrition. Recent studies have shown the existence of glutamate receptors on lymphocytes, thymocytes and thymic stromal cells. In this study, we evaluated the in vitro effect of different MSG concentrations on rat thymocyte apoptosis and expression of two apoptosis-related proteins, Bcl-2 and Bax. Rat thymocytes, obtained from male Wistar rats, were exposed to increasing concentrations of MSG (ranging from 1 mM to 100 mM) for 24 h. Apoptosis was detected using the Annexin V-FITC/PI apoptosis detection kit and cells were analyzed using a flow cytometer. Expression of Bcl-2 and Bax proteins were determined with flow cytometry using respective monoclonal antibodies. Exposure to MSG resulted in a dose-dependent decrease in cell survival (as determined by trypan blue exclusion method). Annexin V-FITC/PI also confirmed that MSG increased, in a dose-dependent manner, apoptotic cell death in rat thymocyte cultures. MSG treatment induced downregulation of Bcl-2 protein, while Bax protein levels were not significantly changed. Our data showed that MSG significantly modulates thymocyte apoptosis rate in cultures. The temporal profile of Bcl-2 and Bax expression after MSG treatment suggests that downregulation of Bcl-2 protein and the resulting change of Bcl-2/Bax protein ratio may be an important event in thymocyte apoptosis triggered by MSG.

Follicular dendritic cell sarcoma in the lymph nodes of the neck.

Follicular dendritic cell sarcoma (FDCS) is a rare tumor, derived from antigen-presenting cells that normally form meshworks in lymphoid follicles. FDCS in general recapitulate the immunophenotypic profile of follicular dendritic cells (FDCs). This tumor affects mainly the lymph nodes, but may arise at a variety of extranodal sites in about one third of cases. We present a case of FDCS in a 52-year-old woman with left neck mass. Histologically, the tumor was composed of oval-to-spindle cells arranged in a fascicular and storiform pattern. Immunohistochemically, the tumor cells were positive for CD21, CD35, and to a lesser extent for EMA and vimentin (Fig. 3, Ref. 14). Full Text (Free, PDF) www.bmj.sk.

Modulatory effect of monosodium glutamate on rat thymocyte proliferation and apoptosis.

BACKGROUND: Monosodium glutamate (MSG) is the sodium salt of glutamic acid, widely spread in modern nutrition. Numerous recent studies have shown the existence of glutamic receptors on different nonneuronal cells, which among others also include lymphocytes and thymocytes. OBJECTIVES: The current study was designed to evaluate the prolonged effect of MSG on rat thymocyte proliferation, apoptosis and expression of two apoptosis related proteins, Bel-2 and Bax. MATERIAL AND METHODS: Wistar rats (male) were exposed to monosodium glutamate (MSG) (4 mg/g body wt, i.p.) for 6 consecutive days and sacrificed on 30th and 45th day after last MSG dose. Thymocyte proliferation was evaluated by measuring the expression of proliferating cell nuclear antigen by flow cytometry. Apoptosis was detected using the Annexin V-FITC/PI apoptosis detection kit and cells were analyzed using a flow cytometer. Expression of Bcl-2 and Bax proteins were determined with flow cytometry using respective monoclonal antibodies. RESULTS: The current study results demonstrate that MSG significantly decreased thymocyte proliferation (p < 0.001) induced by ConA and increased apoptosis rate (p < 0.001) of the cells during examination period. MSG treatment induced down regulation of Bcl-2 protein while Bax protein levels were not significantly changed. CONCLUSION: These results indicate that MSG significantly modulates thymocyte proliferation by modulating the apoptosis rate of the cells. The temporal profile of Bcl-2 and Bax expression, after MSG treatment, suggest that down regulation of Bcl-2 protein and resulting change of Bcl-2/Bax protein ratio may be an important event in thymocyte apoptosis, triggered by MSG (Tab. 1, Fig. 3, Ref. 36).

[Effective revaccination against tetanus in adults]. / Efekti revakcinacije protiv tetanusa kod odraslih.

Immunologic response in persons revaccinated against tetanus was dealt with in this paper. Out of 35 examined patients with the mean age of 47.4 years on the day of revaccination 20% of them had titres of antitetanus antibodies on the lower limit which guaranteed antitetanus protection (0.01-0.02 i.j./m.). Values of titre were below 1.00 i.j./m. in one third of patients. A high degree of negative correlation was statistically established between the age of patients and the height of titre (p less than 0.001). Mean geometric titre (GMT) of the patients amounted to 1.32 i.j./ml on the day of revaccination. Seven days following revaccination GMT was 10.41 i.j./ml and it was the best illustration of immunity "eruption" induced by one dose of Te Al vaccine a 0.5 ml. Optimal values of the titre (over 1.00 i.j./ml) occurred in all examined patients. Dependence of revaccinated titre upon age was of less significance (P = 0.01). A high degree of dependence of revaccinated titre upon the values on the day of revaccination was statistically established (p less than 0.001). It was concluded that by revaccination of persons with the lowest protective titre as well a safe antitetanus protection was provided in a 7-day period. This conclusion also necessitated obligatory immunization against tetanus at an older age too whereby a more expensive active-passive treatment of injured persons would de avoided.

[Bronchogenic cysts of the upper mediastinum]. / Bronchogene Zyste des oberen Mediastinums.

A case report of a congenital bronchogenic cyst in the upper mediastinum on the level of the thoracic aperture, which very likely communicates with the oesophagus, is presented. The embryogenesis, aetiopathogeny, diagnostics, location and histological structure of this rare case are discussed.