Expression of lymphocyte antigenic determinants in developing gut-associated lymphoid tissue of the sea bass Dicentrarchus labrax (L.)

The monoclonal antibodies DLT15 and DLIg3, which recognize antigenic determinants expressed by T cells and Ig-bearing cells, respectively, allowed the development of gut-associated lymphoid tissue of the teleost fish Dicentrarchus labrax (L.) to be studied. DLT15- immunoreactive cells were first detected in the epithelium of the stomach and intestine at day 30 post-hatching of fish maintained at 16° C. At that age, positive cells were found only in the thymus. Between day 44 and day 81 post-hatching, DLT15-immunoreactive cells became numerous, both in and under the gut epithelium. A gradient in the number of lymphocytes was present, concentrating them towards the anus. Until day 81 post-hatching, DLIg3-immunoreactive cells were not found in the gut, although they were present in the kidney, spleen and thymus earlier. Infrequent Ig-bearing cells were found in the gut mucosa of 1-year-old sea bass. This study showed that the gut-associated lymphoid tissue developed earlier than other lymphoid compartments. It also provided evidence of the predominance of T cells in the gut immune system of the sea bass.     

Modulation of Cytokeratin Expression in The Hamster Thymus: Evidence For a Plasticity of The Thymic Epithelium

Cytokeratin (CK) expression was investigated, by means of immunocytochemistry, in the hamster thymic epithelium during ontogeny, as well as in primary cultures and upon glucocorticoid hormone treatment in vivo. As compared to the distribution pattern of distinct monoclonal antibody-defined cytokeratins in the normal adult thymus, CK modulation was evidenced in the three situations studied. During thymus ontogeny, both cytokeratins of simple lining epithelia, as CK8 and CK18, as well as the CK1/CK10 pair (typical marker of terminal stage of keratinization), were expressed since early stages of thymus development. They were located in the central region of thymic lobules preceding the cortical-medullary distinctions. This differed from what had been previously shown for mouse thymus ontogeny, revealing that the interspecific diversity in the distribution pattern of thymic cytokeratins occurred early in fetal life. A modulation of CK expression was also detected when hamster thymic epithelial cells (TEC) were led to grow in culture, with a down-regulation of CK19 contrasting with an enhancement of CK18 expression. This diverged from the maintenance of the in situ pattern when human TEC were cultured. Last, in vivo hydrocortisone treatment, known to increase the numbers of KL1⁺ cells in the mouse thymus medulla, promoted a cortical expression of the CK1/CK10 pair in the hamster thymus. Taken together, our findings demonstrate a continuous plasticity of the thymic epithelium, at least regarding cytokeratin expression, and enlarge the concept of interspecific diversity of intrathymic CK distribution in conditions as morphogenesis, in vitro system, and responsiveness to glucocorticoid hormone treatment.     

Hirschsprung associated GDNF mutations do not prevent RET activation

Hirschsprung disease (HSCR) is a complex disorder characterised by aganglia of distal gastrointestinal tracts. The highest proportion of both familial and sporadic cases is due to mutations of the RET proto-oncogene. Five germline mutations in the glial cell-line-derived neurotrophic factor (GDNF) gene, one of the RET ligands, have been detected in HSCR patients. Pedigrees analysis and the observed association between these GDNF alterations and RET variants in the same patients raised the question of whether the GDNF gene plays any causative/predisposing role in HSCR pathogenesis. In the present work, we have studied the ability of GDNF proteins, each bearing one of the reported mutations, to activate RET by performing a functional test in cultured neuroblastoma cells. Consistently with the lack of genotype/phenotype correlation in human subjects, our results indicate absence of detectable alterations of mutant GDNF induced RET activation.     

Anaphylaxis following psyllium ingestion

Psyllium is a hydrophilic agent found in many bulk laxative preparations. We report the occurrence of an anaphylactic reaction in a patient after ingestion of a psyllium-containing laxative. IgE mediation of the reaction was suggested by a positive immediate skin test to psyllium, positive passive transfer skin test, lack of skin response during passive transfer with heat treated serum, and an elevated IgE (RAST) to psyllium seed.     

Gastroesophageal reflux in asthmatic patients: an incidence study and clinical correlation

The prevalence of gastroesophageal reflux (GER) in asthmatic patients is elevated, but the exact frequency remains unknown. The relationship between GER and asthma has not been investigated in Mexico. The objective of this study is to know the frequency of GER in Mexican asthmatic patients and the possible relationship with the severity of asthma. Fifty patients with adult-onset asthma were studied. AII of them fulfill the diagnostic criteria of the National Institutes of Health, U.S. The evaluation included a symptoms questionnaire, spirometry, esophageal manometry, 24-h esophageal pH-recording, and an upper gastrointestinal endoscopy. Twenty-three patients had mild asthma (46%), 16 moderate (32%) and 11 had severe asthma (22%). Twenty-seven (54%) reported heartburn and regurgitation at least twice a week. The esophageal pH-recording showed pathologic GER in 37 subjects (74%) and endoscopic esophagitis was found in 7 cases (14%). The pH-recording showed pathologic GER in 13 patients with mild asthma (57%), in 13 with moderate asthma (81%) and in all patients with severe asthma (100%). The frequency of GER in Mexican asthmatic patients is high and increases proportionately with the severity of asthma. This factor must be considered in the integral evaluation of these patients.     

The repair of DNA damage induced in human peripheral lymphocytes with styrene oxide

Isolated human peripheral lymphocytes were treated in vitro with styrene-7, 8-oxide (SO) and the kinetics of the repair of induced DNA damage was assessed by comet assay during further incubation of lymphocytes. Using a modified assay we measured simultaneously the number of single strand breaks in DNA (SSBs) and the sites sensitive to endonuclease III (endo III) that most probably represent abasic sites in DNA molecules. SO induced DNA damage in a dose-dependent manner and both SSBs and endo III sites were removed from the DNA by a repair process with a half time about 2-4 hours. The damage was repaired completely within 12 hours after the treatment.     

VCAM-1, but not ICAM-1 or MAdCAM-1, immunoblockade ameliorates DSS-induced colitis in mice

Adhesion molecule immunoneutralization is envisioned as a promising therapy for inflammatory bowel disease, but the relative value of selective blockade of different adhesion molecules has not been established. The aims of this study were to measure expression and functional relevance of endothelial intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and mucosal addressin cell adhesion molecule 1 (MAdCAM-1) in leukocyte recruitment in experimental colitis and to compare the therapeutic effectiveness of their selective blockade. For this purpose, cell adhesion molecule expression was measured by the dual radiolabeled antibody technique in mice with dextran sulfate sodium-induced colitis and controls. Leukocyte-endothelial cell interactions were determined in colonic venules by fluorescence intravital microscopy. Therapeutic effects of chronic treatment with anti-ICAM-1, anti-VCAM-1, or anti-MAdCAM-1 antibodies were also assessed. Whereas colonic endothelial ICAM-1 was constitutively expressed and had a mild up-regulation in colitic animals, constitutive expression of VCAM-1 and MAdCAM-1 was low, but markedly increased after induction of colitis. Leukocyte adhesion was abrogated by immunoneutralization of VCAM-1 or MAdCAM-1 but not by treatment with an anti-ICAM-1 antibody. Chronic administration of anti-VCAM-1 antibody, but not anti-ICAM-1 or anti-MAdCAM-1, resulted in significant attenuation of colitis in terms of disease activity index, colon length, ratio of colon weight to length, and myeloperoxidase activity. In conclusion, VCAM-1 plays a central role in leukocyte recruitment in colitis and blockade of this adhesion molecule has higher therapeutic effect than immunoneutralization of ICAM-1 or MAdCAM-1 in this experimental model.     

Dietary Habits,Selenium, Copper,Zinc and Total Antioxidant Status in Serum in Relation to Cognitive Functions of Patients with Alzheimer’s Disease

Oxidative stress plays a crucial role in the neurodegenerative process and can impair cognitive functions. In the prevention of Alzheimer’s disease (AD), an adequate consumption of dietary antioxidants may be a major factor. The objective of the study was to estimate selenium (Se), copper (Cu), zinc (Zn), and total antioxidant status (TAS) in the serum of patients with AD in relation to their cognitive functions and dietary habits. A total of 110 patients (aged 54–93 years) with early or moderate AD, as well as 60 healthy people (aged 52–83 years) were studied. The severity of the disease was assessed using the mini-mental state examination (MMSE) scale. Food-frequency questionnaires were implemented to collect the dietary data. The concentrations of Se, Cu and Zn in the sera were determined by the atomic absorption spectrometry method. TAS was estimated spectrophotometrically using ready-made kits (Randox). Significantly lower concentrations of Se, Zn and TAS, and higher Cu:Zn ratio in the serum of patients with AD, compared to healthy people, were observed. A low correlation between the MMSE score and TAS in the serum of AD patients and significantly higher MMSE values in patients with TAS above the reference range were also noted. In patients with serum Cu concentration above the norm, significantly lower MMSE values were found. Selected dietary habits such as the frequency of consumption of various food products had a significant impact on the concentration of the assessed parameters in the serum of people with AD.     

L-Glutamine Supplementation Enhances Strength and Power of Knee Muscles and Improves Glycemia Control and Plasma Redox Balance in Exercising Elderly Women

We investigated the effects of oral L-glutamine (Gln) supplementation, associated or not with physical exercises, in control of glycemia, oxidative stress, and strength/power of knee muscles in elderly women. Physically active (n = 21) and sedentary (n = 23) elderly women aged 60 to 80 years were enrolled in the study. Plasma levels of D-fructosamine, insulin, reduced (GSH) and oxidized (GSSG) glutathione, iron, uric acid, and thiobarbituric acid-reactive substances (TBARs) (lipoperoxidation product), as well as knee extensor/flexor muscle torque peak and average power (isokinetic test), were assessed pre- and post-supplementation with Gln or placebo (30 days). Higher plasma D-fructosamine, insulin, and iron levels, and lower strength/power of knee muscles were found pre-supplementation in the NPE group than in the PE group. Post-supplementation, Gln subgroups showed higher levels of GSH, GSSG, and torque peak, besides lower D-fructosamine than pre-supplementation values. Higher muscle average power and plasma uric acid levels were reported in the PE + Gln group, whereas lower insulin levels were found in the NPE + Gln than pre-supplementation values. TBARs levels were diminished post-supplementation in all groups. Gln supplementation, mainly when associated with physical exercises, improves strength and power of knee muscles and glycemia control, besides boosting plasma antioxidant capacity of elderly women.