Ultrastructural analysis of pancreatic acinar cells from mice fed on genetically modified soybean

No direct evidence that genetically modified (GM) food may represent a possible danger for health has been reported so far; however, the scientific literature in this field is quite poor. Therefore, we investigated the possible effects of a diet containing GM soybean on mouse exocrine pancreas by means of ultrastructural, morphometrical and immunocytochemical analyses. Our observations demonstrate that, although no structural modification occurs in pancreatic acinar cells of mice fed on GM soybean, quantitative changes of some cellular constituents take place in comparison to control animals. In particular, a diet containing significant amount of GM food seems to influence the zymogen synthesis and processing.     

Chemically modified tetracycline (CMT)-3 inhibits histamine release and cytokine production in mast cells: possible involvement of protein kinase C

Objective: To find novel inhibitors of mast cell function we have studied the effect of a potent, non-antimicrobial, chemically modified tetracycline, CMT-3 or COL-3, on key functions of mast cells.Methods and Results: In the presence of 25 μM CMT-3, the 48/80-induced histamine release from rat serosal mast cells was inhibited significantly, to 43.0 ± 7.3% of control. Similarily, the activation-induced secretion of TNF-α and IL-8 by HMC-1 cells were decreased in the presence of 25 μM CMT-3 to 13.5 ± 4.1% and 9.7 ± 1.1% of control, respectively. CMT-3 did not cause intracellular accumulation of TNF-α but instead it reduced the expression of TNF-α mRNA in HMC-1 cells. Moreover, CMT-3 was found to significantly inhibit the protein kinase C (PKC) activity with IC₅₀ value of 31 μM. CMT-3 inhibited effectively both human recombinant PKCalpha and PKCdelta isoforms. In comparison to doxycycline, CMT-3 was more effective as an inhibitor of both cytokine production and PKC activity.Conclusions: Considering the central role of PKC in mast cell activation, PKC inhibition could, at least partially, explain the observed inhibitory effects of CMT-3. The inhibition of the key proinflammatory functions of mast cells by CMT-3 suggests its potential clinical usefulness in the treatment of allergic and inflammatory disorders.Received 18 February 2005; returned for revision 7 March 2005; accepted by A. Falus 21 April 2005     

Recombinant interferon alpha 2 stimulation of target-binding by natural killer cells

Summary Even though the enhancement of the lyitc capacity and the kinetics of lysis of natural killer cells (NK) by interferon has been well documented, an increase of the target-effector cell binding percentage is still disputed. We, therefore, modified the Grimm-Bonavida single-cell assay so that 400 to 600 cells per individual determination could be reliably evaluated. Using this assay, which makes possible separate determination of effector-target cell binding and target lysis, we demonstrated that, in addition to lytic capacity, target-effector cell binding is also increased by preincubating NK with 100 to 1,000 IU interferon alpha 2 per 10⁶ cells. Our data indicate that interferon alpha 2 induces pre-NK cells to bind target cells and that it activates these pre-NK cells to kill the targets.Abbreviations NK Natural killer cells - LCMV Lymphocytic choriomeningitis virus - IFN Interferon - FCS Fetal calf serum - RPMI 1640 Culture medium Dedicated to Prof. H.D. Waller on the occasion of his 60^th birthday     

Induction of immunoglobulin-producing human peripheral blood lymphocytes in serum-free medium

Induction of immunoglobulin-secreting cells from human peripheral blood lymphocytes in a serum-free culture medium was studied. Albumin, transferrin, insulin and fibronectin can replace serum entirely for support of pokeweed mitogen (PWM)-stimulated B lymphocytes, measured by a reverse hemolytic plaque assay using protein A-coated red cells. In this serum-free system, growth and maturation to IgM and IgG secretion occur at the same or higher efficiency as in conventional serum-containing medium, with maximum numbers of plaque-forming cells on day 6 at optimal dose of PWM, 0.5 ～ 5 μg/ml. This system can be used to avoid the interference from undefined serum components.     

Monoclonal antibodies to three distinct epitopes on human IgE: their use for determination of allergen-specific IgE

Three different monoclonal antibodies (MAb) against human immunoglobulin E have been obtained which specifically bind to human myeloma and polyclonal IgE. The antibodies showed high avidities for soluble IgE (0.7 X 10(9) to 3.3 X 10(9) M-1). These MAb defined three distinct epitopes on IgE. A mixture of these antibodies in combination with an 125I-labelled anti-mouse Kappa chain MAb has been used to measure allergen-specific IgE. This determination was performed by a solid-phase radioimmunoassay using allergen extracts coated to either chemically activated paper discs or to polyvinyl chloride wells. This method is 4-10 times more sensitive than other previously reported procedures. A similar technique has also been applied to detect individual allergens in immunoblots of allergen extracts.     

Comparison of electrical field plethysmography with electrical impedance plethysmography

As a means for assessing cardiac function, electrical field plethysmography (EFP) has been shown to have some features quite different from electrical impedance plethysmography (EIP). Here the two techniques are compared by using the two systems simultaneously on a subject and also with independent use in different electrode configurations. The results conform with the view that EIP is related primarily to volumetric changes of the aorta, whereas EFP is affected predominantly by changes in cardiac dimensions and orientation. Because of this difference, the standard time differential formula used for EIP is not applicable for the computation of cardiac output from the EFP waveforms. An alternative method of computation based on the amplitude of the EFP waveform is suggested.     

Whey hydrolysate compared with cow's milk-based formula for weaning at about 6 months of age in high allergy-risk infants: effects on atopic disease and sensitization

Ninety-one high atopy-risk infants were prospectively followed up to 18 months of age with regard to the development of allergic/atopic manifestations and sensitization. They were randomized into one of two feeding groups, i.e., a hydrolyzed, ultrafiltered cow's milk whey formula, Profylac® ( n = 32), or an ordinary cow's milk formula ( n = 39), for 12 months, started after exclusive breast-feeding for 0–9 (median 6.0) months. Lactating mothers avoided milk, egg, and fish, as did the infants up to 12 months of age. Twenty of the 91 infants were breast-fed exclusively for more than 9 months and regarded as a control group. All infants were followed-up by questionnaires, physical examinations, skin prick tests, and determination of serum total IgE and cow's milk-specific IgE. The frequency of allergic/atopic disease was similar in the three groups. However, all three infants who developed cow's milk allergy with skin symptoms belonged to the cow's milk formula group. The skin prick test with whey hydrolysate was negative in all, while with cow's milk it was positive in eight infants. Growth was similar in the three groups. The study comprises too few infants to allow us to make statistically based statements. However, the difficulties encountered and the limited effects obtained by the use of whey hydrolysate at weaning at about 6 months of age made us conclude that we can spare high atopy-risk families this extra burden.     

A sensitive enzyme-linked immunosorbent assay for determination of bovine β-lactoglobulin in infant feeding formulas and in human milk

We developed a sensitive sandwich-type ELISA for measuring low levels of cow's milk (CM) β-lactoglobulin. Purified anti-β-lactoglobulin was used as coating antibody and also as second antibody conjugated with alkaline phosphatase. Polyethylene glycol 6000 was added to the incubation buffers to improve sensitivity. The detection limit of the assay was 0.002 μg/l, which is much better than sensitivities reported for other β-lactoglobulin assays. The sensitivity was not impaired by the presence of other CM proteins. The recovery from breast milk was 93% and from the diluting buffer 127%. The coefficient of variation within day was 5–15% and between days 10%. One hour after oral intake of milk, P-lactoglobulin could be detected in the breast milk of three mothers at concentrations of about 1–2 μg/l. Widely different concentrations of β-lactoglobulin were measured in two protein hydrolysates based on CM whey and casein proteins; the observed concentrations were 200 and 0.0056 μg P-lactoglobulinμ/g dry weight, respectively.     

The N-terminal flanking region of the invariant chain peptide augments the immunogenicity of a cryptic "self" epitope from a tumor-associated antigen

The N-terminal flanking region of the invariant chain peptide termed CLIP appears to have superagonistic properties interacting with the T cell receptor and the MHC class II molecule at or near the binding site for the bacterial superantigen Staphylococcal enterotoxin B (SEB). The present studies explored the hypothesis that the N-terminal segment of CLIP can augment the immunogenicity of cryptic "self" tumor-associated antigens. A chimeric construct of an MHC class II binding peptide from the c-erb oncogene (Her-2/neu) containing the N-terminal flanking region of CLIP elicited potent antitumor activity against a Her-2/neu-positive tumor in a rat model system. Comparatively, the unmodified parent peptide was ineffective. The induction of effective antitumor immunity, however, required presentation of the chimeric peptide construct on irradiated tumor cells or the peptide construct in concert with a Her-2/neu MHC class I-restricted peptide from Her-2/neu. As revealed by adoptive transfer studies, effective protective antitumor immunity in this setting required the CD4 T helper subset. Additionally, in vitro analysis revealed that immunization with the parent peptide resulted in a weak immune response to the unmodified peptide consisting of both type 1 (IL-2, IFN-gamma) and type 2 (IL-4, IL-10) cytokine-producing cells analyzed by RT-PCR (qualitative and quantitative) and by limiting dilution assay. Comparatively, immunization with the chimeric construct elicited a potent immune response to the parent peptide with predominantly type 1 cytokine-producing cells. Taken together, the results suggest that immunization with the chimeric Her-2/neu peptide induced protective antitumor immunity. Associated with this immunization strategy was the enhancement of a type 1 cytokine response.     

Hydrophobically Modified Poly(acrylic acid) Using 3‐Pentadecylcyclohexylamine: Synthesis and Rheology

Summary: Hydrophobically modified poly(acrylic acid) was synthesized using 3‐pentadecylcyclohexylamine (3‐PDCA), which was in turn synthesized from 3‐pentadecylphenol, one of the components of cashew‐nut shell liquid (CNSL), a renewable resource material. ¹H NMR spectra confirmed the incorporation of 3‐PDCA onto PAA and a series of HMPs with three different molar concentrations, viz ? 3, 5 and 7 mol‐% of 3‐PDCA, were synthesized. An increase in viscosity with increasing hydrophobic content was observed by rheological measurements. The critical association concentrations were determined using an Ubbelohde viscometer and a controlled stress rheometer. The stability of HMPs towards temperature and shear was studied. Rheological measurements showed that there was a steady increase in viscosity with increase in hydrophobe content due to the formation of reversible networks. These polymers exhibited gel‐like behavior at low concentrations (≥2 wt.‐%) with an apparent yield stress (ca. 10 Pa) and showed shear thinning properties (non‐Newtonian). However, below a critical concentration, c [η], they showed Newtonian behavior.

η_sp of unmodified and modified PAA‐Na at various polymer concentrations.