Because retinal pericytes have contractile properties and are affected by diabetes, we have studied the responsiveness of pericytes to ET-1, a potent vasoconstrictor, in the presence of various concentrations of glucose. Cultured calf retinal pericytes were exposed to glucose levels of 5.5 or 25 mM for up to 8 days. Radioreceptor studies that used [125I]ET-1 showed that pericytes contained high-affinity binding sites with Kd of 3 x 10(-10) M, and these binding affinities were unaffected by glucose concentration. Receptor number appears to be elevated, but this increase was NS. Responsiveness of pericytes to ET-1 was studied with respect to stimulation of DAG and IP3 levels and PKC activities. In contrast to receptor binding, exposure to 25 mM glucose for > 6 days blunted pericyte responsiveness to ET-1. The time course of ET-1 stimulation as measured by [3H]glycerol labeling, and IP3 level showed a 98% increase in [3H]DAG at 10 min and a fourfold increase for IP3, respectively. Cells exposed to 25 mM glucose only had a 32% increase for DAG, and no increase for IP3 was observed. Dose-response studies on the stimulation of [3H]DAG increase showed the range of ET-1's effect to be between 10(-9) and 10(-7) M. At maximum, cells exposed to 5.5 mM glucose had a 70% increase versus only a 30% increase in those exposed to 25 mM glucose. Similarly, ET-1 only increased the total DAG levels in pericytes exposed to 5.5 mM glucose by 41%. PKC activity also was measured because DAG is one of its cellular activators.(ABSTRACT TRUNCATED AT 250 WORDS)

Single recombinant latex allergens permit the study of the pattern of sensitization to individual allergens. We aimed to quantify the IgE-response to individual latex allergens in children sensitized to latex. The study group included 31 latex-sensitized children: 26 operated at least twice, 20 of them with spina bifida; two children with one operation and three atopic non-operated children. IgE antibodies to rHev b 1, rHev b 3, rHev b 5, rHev b 6.01, rHev b 7.02 and rHev b 8, coupled to ImmunoCAPs, were measured in each serum. IgE responses to rHev b 1, rHev b 5 and rHev b 6.01 were found in 17 children each, and their mean +/- s.d. levels were 5 +/- 7.4, 16.8 +/- 14 and 10 +/- 18 kU/l, respectively. IgE responses to rHev b 3 (4 +/- 5.4 kU/l) were found in eight children. Two children had IgE to rHev b 7 (1.7 and 3.2 kU/l), and none to rHev b 8. Four sera were negative to all tested recombinant allergens. We divided the patients in three groups: sensitized only to rHev b 1, sensitized only to rHev b 5 and/or rHev b 6.01, and sensitized to both rHev b 1 and to rHev b 5 and/or rHev b 6.01. The three groups had the same profile of clinical features. Hev b 5 induces the quantitatively higher IgE responses in children with multiple surgeries sensitized to latex. Responses to Hev b 6.01 equal those of Hev b 1.

Children with short bowel syndrome (SBS) undergo frequent operations, so they are at risk for sensitizing to latex. There have been isolated reports of sensitization to food in these children. In a cross-sectional study, we assessed sensitization to latex, cow's milk, and egg with skin prick tests (SPT) and serum-specific immunoglobulin E (IgE) in 14 children with SBS. Data were collected about the number of operations with latex devices, serum total IgE, and history of feeding with milk formula. Ten children were sensitized to latex (specific IgE median: 6.7 kU/l, range: 0.5-33). Compared with those non-sensitized, sensitized children had significantly (p < 0.05) higher levels of serum total IgE in z-units (mean rank 3.25 vs. 9.2, respectively), and more operations with latex devices (mean rank 3.75 vs. 9). Eight children were sensitized to cow's milk, one with only positive SPT, the other seven with serum-specific IgE (median: 3.5, range: 0.5-21.1 kU/l), and five to egg (specific IgE median: 0.68, range: 0.58-2.17 kU/l). Except for some isolated days with cow's milk formula, the children had been initially fed with a diet without intact cow's milk proteins. Sensitization to latex, cow's milk, and egg is very frequent in children with SBS. They should be treated in a latex-free environment since the very early stages of the disease, and should be routinely studied regarding food sensitization, as this might contribute as an added factor in the chronic diarrhea of these patients.

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The antigenic protein Ro52 was expressed in the E. coli system harboring a 6 x His tag in the form of insoluble inclusion bodies. Direct chemical extraction of the product using 6-8 M urea proved to be effective. Furthermore, the tagged protein was recovered by direct adsorption on Ni2+-loaded commercial adsorbents derivatized with iminodiacetic acid. Screening experiments in small packed columns revealed that selective binding and elution were possible using a denaturing buffer at pH 4.5. The hydrodynamic evaluation of scaled-up fluidized systems showed values for the phi (dynamic zone) parameter in the range 0.95-1.00 for fluidization in buffer and in the range 0.70-0.85 for the biomass-containing feedstock. Removal of macromolecular DNA released by the disrupted biomass was mandatory. Under optimized process conditions good recovery (60-70%) was achieved and a highly purified (95%) product obtained. The purified Ro52 retained its immunoreactivity against sera of patients with systemic lupus erythematosus (SLE) and Sjogren's syndrome-related disorders. The production and application of new recombinant antigens may contribute to increasing the sensitivity and specificity of the detection of anti-Ro antibodies in these autoimmune diseases.

Because retinal pericytes have contractile properties and are affected by diabetes, we have studied the responsiveness of pericytes to ET-1, a potent vasoconstrictor, in the presence of various concentrations of glucose. Cultured calf retinal pericytes were exposed to glucose levels of 5.5 or 25 mM for up to 8 days. Radioreceptor studies that used [ 125 I]ET-1 showed that pericytes contained high-affinity binding sites with /Q of 3 x 1O~1 0 M, and these binding affinities were unaffected by glucose concentration. Receptor number appears to be elevated, but this increase was NS. Responsiveness of pericytes to ET-1 was studied with respect to stimulation of DAG and IP 3 levels and PKC activities. In contrast to receptor binding, exposure to 25 mM glucose for >6 days blunted pericyte responsiveness to ET-1. The time course of ET-1 stimulation as measured by [ 3 H]glycerol labeling, and IP 3 level showed a 98% increase in [ 3 H]DAG at 10 min and a fourfold increase for IP 3 , respectively. Cells exposed to 25 mM glucose only had a 32% increase for DAG, and no increase for IP 3 was observed. Dose-response studies on the stimulation of [ 3 H]DAG increase showed the range of ET-1's effect to be between 10" 9 and 1 0 7 M. At maximum, cells exposed to 5.5 mM glucose had a 70% increase versus only a 30% increase in those exposed to 25 mM glucose. Similarly, ET-1 only increased the total DAG levels in pericytes exposed to 5.5 mM glucose by 41%. PKC activity also was measured

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