Feature of food allergy developed during infancy (1)--relationship between infantile atopic dermatitis and food allergy]

BACKGROUND: Most of food allergy (FA) cases during childhood start as infantile atopic dermatitis (AD) at the ages of a few months old. We tried to clarify the association between infantile AD and FA during infancy. METHODS: We analyzed relationship between AD and FA during infancy among patients with 208 cases, who had visited our outpatient clinic with chief complaint of "eczema" from 1998 to 2000. RESULTS: Among 208 cases, 148 cases (71%) were diagnosed as infantile AD, moreover 109 cases (74%) were diagnosed as FA among infantile AD. The most frequent food antigens among infantile AD were egg (72.3%), cow's milk (39.9%), wheat (12.2%) and soybean (7.4%), respectively, in addition to these food antigens, food allergy was widely recognized against peanuts, sesame, meats, buckwheat, fishes and potato. In terms of food antigen, 44 cases with single food allergy against egg were seen out of 46 single allergy cases, whereas 36 cases with double food allergy against both egg and cow's milk were seen in 63 multiple food allergy cases. Although the value of antigen specific IgE against egg and cow's milk was recognized for the diagnosis of food allergy during infancy, even cases with negative IgE against those foods were proved to be food allergy by food elimination and provocation tests. In contrast to egg and cow's milk, positive IgE against rice, soybean, and wheat did not always correlate with the results of the diagnosis of food allergy. Concerning risk factors of AD, family history of any allergy diseases and passive smoking were recognized in comparison with infantile eczema. Neither the nutrition method nor incomplete elimination of diet during pregnancy and lactation had anything to do with the development of AD. CONCLUSION: When infantile AD cases were not improved by environmental control, skin care and application of steroid ointment, it would be important for doctors to think of the possibility of FA.     

Determination of food specific IgE levels over time can predict the development of tolerance in cow's milk and hen's egg allergy

BACKGROUND: The majority of children with cow's milk and hen's egg allergy develop clinical tolerance with time. However, there are no good indices to predict when and in whom this occurs. OBJECTIVE: The aim of this study was to determine if monitoring food specific IgE levels over time could be used as a predictor for determining when patients develop clinical tolerance. METHODS: Eighty-eight patients with hen's egg and 49 patients with cow's milk allergy who underwent repeated double-blind, placebo-controlled food challenges were included in the study. Using the Pharmacia CAP-System FEIA, specific IgE (sIgE) levels to cow's milk and hen's egg were retrospectively determined from stored serum samples obtained at the time of the food challenges. Logistic regression was used to evaluate the relationship between tolerance development and the decrease in sIgE levels over a specific time period between the two challenges. RESULTS: Twenty-eight of the 66 egg-allergic and 16 of the 33 milk-allergic patients lost their allergy over time. For egg, the decrease in sIgE levels (P=.0014) was significantly related to the probability of developing clinical tolerance, with the duration between challenges having an influence (P=.06). For milk there also was a significant relationship between the decrease in sIgE levels (P=.0175) and the probability of developing tolerance to milk but no significant contribution with regard to time. Stratification into 2 age groups, those below 4 years of age and those above 4 years of age at time of first challenge, had an effect, with the younger age group being more likely to develop clinical tolerance in relation to the rate of decrease in sIgE. The median food sIgE level at diagnosis was significantly less for the group developing "tolerance" to egg (P <.001), and a similar trend was seen for milk allergy (P=.06). Using these results, we developed a model for predicting the likelihood of developing tolerance in milk and egg allergy based on the decrease in food sIgE over time. CONCLUSION: We found that the rate of decrease in food sIgE levels over time was predictive for the likelihood of developing tolerance in milk and egg allergy. Using the likelihood estimates from this study could aid clinicians in providing prognostic information and in timing subsequent food challenges, thereby decreasing the number of premature and unnecessary double-blind, placebo-controlled food challenges.     

Anaphylactic reactions to a cow's milk whey protein hydrolysate (Alfa-Ré, Nestlé) in infants with cow's milk allergy

It has been shown in an animal model that cow's milk (CM) protein hydrolysates do not elicit an antibody response to CM proteins and do not induce passive cutaneous anaphylaxis. In addition, babies fed with these formulae during the first months of life do not show antibodies to betalactoglobulin (BLG). These data suggest that these hydrolysates are not antigenic, therefore they have been employed as CM substitutes for the management of infants with CM allergy (CMA). We report five exclusively breast fed infants aged 3 to 8 months (median age = 5 mo) with IgE-mediated CMA, who experienced allergic reactions when they were first fed (median age = 5 months) with a small amount of CM whey protein hydrolysate (Alfa-Ré, Nestlé). Family history was positive for atopy in 3/5 babies. All infants had atopic dermatitis during breastfeeding, positive skin tests, and RAST to CM proteins as well as to Alfa-Ré. Total IgE levels ranged from 45 to 2,990 U/mL. These data show that Alfa-Ré, a CM whey protein trypsin hydrolysate, can trigger severe allergic reactions in children with CMA and it should be employed with great caution as a CM substitute in the management of CMA.     

Evaluation of food allergy to wheat,cow milk,egg, soy and peanuts in patients suffering from atopic dermatitis

Few large studies concerning the importance of food allergy in adolescents and adult patients with atopic dermatitis exist. The evaluation of food allergy to egg white and yolk, peanuts, soy, cow milk and wheat in patients suffering from atopic dermatitis. Two hundred forty patients (70 men, 170 women) were examined. Complete dermatological and allergological examination was performed in all patients, including specific IgE, skin prick test and atopy patch test. The challenge test was performed according to the results of examinations with suspected foods. The food allergy to peanuts was confirmed in 20% of patients, to egg in 6%, to soy in 3.3%, to wheat in 2.5% and to milk in 0.8% – altogether in 65 patients (27.5%). The positive results in examinations without clinical symptoms of food allergy were recorded in another 78 patients (32.5%). The diagnostic work-up should comprise not only the laboratory methods, but also the diagnostic hypoallergenic diet and the challenge test.     

A follow-up study of children with food allergy. Clinical course in relation to serum IgE- and IgG-antibody levels to milk, egg and fish

Eighty-two children with food sensitivity were followed-up for 2-5 years. Most children showed a decreasing sensitivity and the clinical course of food allergy seemed to reflect the course of the humoral immune responses to the offending foods. The occurrence of IgE- and IgG-antibodies parallelled in most cases. However, an early, high IgG/IgE food antibody ratio seemed to be a good prognostic sign, indicating a possible blocking capacity of IgG-antibodies.     

A pilot study of the usefulness and safety of a ready-to-use atopy patch test (Diallertest) versus a comparator (Finn Chamber) during cow's milk allergy in children

BACKGROUND: Patch testing is used in the diagnosis of food allergy, especially during delayed manifestations. OBJECTIVE: A ready-to-use atopy patch test (APT), the Diallertest, was compared with another APT device, the Finn Chamber, in pediatric cow's milk allergy. METHODS: This prospective study involved 49 children (34.3 +/- 17 [mean +/- SD] months of age), with cow's milk allergy manifested by atopic dermatitis (10.2%), digestive manifestations (40.8%), or both (49%). All children underwent both APT techniques, with a reading 72 hours after application, followed by a milk elimination diet for 4 to 6 weeks and open cow's milk challenge. RESULTS: A positive result was seen in 22 (44.8%) versus 13 (26.5%) patients with the ready-to-use and the comparator APTs, respectively. No side effects were recorded. Both techniques were concordant in 67.3% of patients. Of the total 41 open cow's milk challenges, 60.9% had positive results, with 8 patients lost to follow-up. The performances of the ready-to-use and comparator APTs were as follows: sensitivity, 76% (95% CI, 59.2% to 92.7%) versus 44% (95% CI, 24.5% to 63.4%; P = .02); specificity, 93.8% (95% CI, 81.9% to 100%) versus 93.8% (95% CI, 81.9% to 100%); positive predictive value, 95% (95% CI, 85.4% to 100%; 1 false-positive result) versus 91.7% (95% CI, 76% to 100%; 1 false-positive result); negative predictive value, 71.4% (95% CI, 52% to 90.7%; 6 false-negative results) versus 51.7% (95% CI, 33.5% to 69.8%; 14 false-negative results); and test accuracy, 82.9% (95% CI, 71.3% to 94.5%) versus 63.4% (95% CI, 48.6% to 78.1%; P = .05). CONCLUSION: The ready-to-use APT exhibited a good sensitivity and specificity, with no side effects.     

The study of allergic children under one-year old. The measurement of IgE and IgG4 antibody titers to egg white, milk and soybean

We measured the IgE and IgG4 antibody titers to egg white, and soybean of 94 allergic children under one year. (21 wheezy children, 35 atopic dermatitis, 34 wheezy children with atopic dermatitis, and 4 other allergic children). The results were as follows; 1) The positive ratio of IgE antibody titers to egg white was higher than the other IgE antibody titers, and of IgG4 antibody titers to milk was higher than the other IgG4 antibody titers. 2) Of each allergic symptoms, the positive ratio of IgG4 antibody titers to milk was higher than the others in wheezy children group. And the positive ratio of IgE antibody titers to egg white and milk were higher than the others in atopic children and wheezy children with atopic dermatitis. 3) The positive ratio of IgE antibody titers to egg white and milk were higher than the others in the group showed IgE RIST more than 21 IU/ml, and then the positive ratio of IgE antibody titers to egg white, milk and soybean and IgG4 antibody titers to egg white were higher than the others in the group showed eosinophil counts more than 301/mm3.     

Duration of clinical reactivity in cow's milk allergy is associated with levels of specific immunoglobulin G4 and immunoglobulin A antibodies to β‐lactoglobulin

Background The development of tolerance in IgE‐mediated allergies has been associated with lower cow's milk (CM)‐specific IgE levels, increasing levels of specific IgG4 and, more contestably, IgA. Objective We investigated whether specific antibody responses to CM proteins differ over time between patients who recovered from cow's milk allergy (CMA) by the age of 3 years and those who developed tolerance only after the age of 8 years. Methods The study population comprised of 83 patients with IgE‐mediated CMA. They belonged to a cohort of 6209 healthy, full‐term infants followed prospectively for the emergence of CMA. Serum samples were available at diagnosis (median age 7 months), 1 year later (median 19 months) and at follow‐up (median 8.5 years). Age‐matched control subjects with no history of CMA (n=76) participated in the follow‐up. Serum levels of IgE antibodies to CM were measured using UniCAP. Levels of IgA, IgG1 and IgG4 antibodies to β‐lactoglobulin and α‐casein were measured using ELISA. Results Patients with persistent CMA at the age of 8 years (n=18 at diagnosis, n=16 at later time‐points) had higher CM‐specific IgE levels at all three time‐points (P<0.001) compared with patients who became tolerant by 3 years (n=55 at diagnosis, n=54 a year later, n=40 at follow‐up). They had lower serum IgA levels to β‐lactoglobulin at diagnosis (P=0.01), and lower IgG4 levels to β‐lactoglobulin (P=0.04) and α‐casein (P=0.05) at follow‐up. Conclusion High CM‐specific IgE levels predict the persistence of CMA. Development of tolerance is associated with elevated levels of β‐lactoglobulin‐specific serum IgA at the time of diagnosis, and later increasing specific IgG4 levels to β‐lactoglobulin and α‐casein. Cite this as: E. M. Savilahti, K. M. Saarinen and E. Savilahti, Clinical & Experimental Allergy, 2010 (40) 251–256.     

Detection and characterization of antibodies specific to food antigens (gliadin,ovalbumin and β-lactoglobulin) in human serum,saliva, colostrum and milk

Antibodies against food antigens are usually produced in healthy people. This humoral response can be detected both in serum and secretions. The characterization of this response can be useful for a better understanding of food-related immunological alterations. In this study, IgA and IgG antibodies specific to ovalbumin, β-lactoglobulin or gliadin were measured in serum, saliva, colostrum and milk from 40 healthy breast-feeding women. Specific IgA and IgG to the three antigens were measured by indirect ELISA. Specific IgG levels were highest in serum and very low in the other biological fluids. No correlation between the IgG specific to the different antigens was found. Specific IgA reactivity was found in all the samples analysed. Levels observed were higher in colostrum and milk than in serum and saliva. In spite of being three different unrelated food antigens, a correlation between the levels of specific IgA was found in saliva, colostrum and milk samples of all subjects studied. The specificity of IgA anti-gliadin antibodies from serum, saliva and colostrum was analysed by immunoblotting of SDS–PAGE-separated wheat proteins. Each sample presented a unique pattern of recognition. No common pattern of recognition was found either among the same biological fluids of the different subjects tested, or among the different samples—either serum, colostrum or saliva—of the same individual. Different degrees of specificity to wheat proteins among IgA from colostrum, saliva or serum were observed, suggesting that the local IgA-producing populations are functionally different in the different tissues of the organism.     

Genotoxic activity of the N-acetylated metabolites of the food mutagens 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and 2-amino-3, 4-dimethylimidazo[4,5-f]quinoline (MeIQ)

The genotoxic potential of the food mutagens 2-amino-3-methylimidazo[4,5-f]quinoline(IQ) and 2-amino-3,4-di-methylimidazo[4,5-f]quinoline (MelQ)and their N-acetylated metabolites (AcIQ and AcMelQ, respectively)has been studied, in order to evaluate whether an initial N-acetylationof IQ or MelQ is important for the overall in vivo genotoxicityof the compounds. When incubated with uninduced (control) rathepatocytes, both the acetylated and the unacetylated compoundsappeared to be relatively stable, whereas water-soluble metabolites(i.e. not extractable by ethyl acetate at alkaline pH) wererapidly formed with hepatocytes from PCB-induced animals. NoDNA damage was induced by IQ or MelQ in hepatocytes isolatedfrom control rats, as measured by alkaline elution. In hepatocytesfrom PCB-pretreated rats, IQ, MelQ, AcIQ and AcMelQ inducedDNA damage at low (10^–6 M) concentrations, with AcIQ beingmore potent than IQ whereas AcMelQ was less potent than MelQ.Similar patterns were observed when unscheduled DNA synthesiswas measured in hepatocytes. The compounds induced sister chromatidexchanges in Chinese hamster V79 cells with PCB-induced hepatocytesas activation system; IQ and AcIQ were equal while AcMelQ hadless activity than MelQ. The compounds were also compared inbacterial mutagenesis test systems (Salmonella typhimurium TA98).With hepatocyte activation, AcIQ was slightly more potent thanIQ, whereas AcMelQ was markedly less mutagenic than MelQ. Withsub-cellular fractions as activation system (rat liver S9 ormicro-somes), the N-acetylated compounds were similar to orless mutagenic than their parent compounds. The mutagenic effectsof AcIQ and AcMelQ in bacteria with microsomal activation weremarkedly reduced by the deacetylase inhibitor paraoxon. Paraoxonalso reduced the DNA strand breaks induced by AcIQ or AcMelQin PCB-induced hepatocytes, but did not affect IQ- or MelQ-inducedDNA damage. The results show that an initial N-acetylation ofIQ or MelQ does not dramatically change the overall genotoxicityof these hetrocyclic aromatic amines.     

Measurement of IgE antibodies against purified grass pollen allergens (Lol p 1, 2, 3 and 5) during immunotherapy

Background IgE titres tend to rise early after the start of immunotherapy, followed by a decline to pre-immunotherapy levels or lower. Objectives We were interested to ktiow whether the early increase in IgE antibodies includes new specificities of IgE, and whether these responses persist. Methods Sera of 64 patients undergoing grass pollen immunotherapy were tested for IgE against four purified grass pollen allergens: Lol p 1. 2, 3, and 5. At least two serum samples were taken, one before the start of therapy and one between 5 and 18 months after the first immunization (mean: 10 months). Results The mean IgE responses to Lol p 1, 2 and 3 showed a moderate but not significant increase. In contrast, the mean IgE response to Lol p 5 showed a significant decrease of >30%. IgE against total Lolium perenne pollen extract moderately increased (>20%), showing that a RAST for total pollen is not always indicative for the development of IgE against its major allergens. For >40% of the patients it was found that IgE against one or more of the four allergens increased, while IgE against the remaining allergen(s) decreased. Eor 10 sera the ratio of IgE titres against at least two allergens changed by at least a factor of 5. The changes in specific IgE also included conversions from negative (< 0.1 RU) to positive (0.6 to 5.0 RU) for five patients. For two patients, the induction of these ‘new’ IgE antibodies against major allergens was shown to result in a response that was persistent over several years. Conclusion Although active induction of new IgE specificities by immunotherapy was not really proven, the observations in this study indicate that monitoring of IgE against purified (major) allergens is necessary to evaluate changes in specific IgE in a reliable way.     

Immunomodulating and Antimetastatic Activity of 3-(P-Chlorophenyl) Thiazolo[3, 2-A]Benzimidazole-2-Acetic Acid (Wy-18, 251, Nsc 310633)

The antimetastatic activity of a thiazolobenzimidazole, Wy-18, 251 was investigated using various dosage regimens in mice with implanted Lewis lung tumors. The low doses, 1 and 5 mg/kg (i.p.) given 24 hours after implantation with two subsequent doses at 1 week intervals were most effective in reducing lung metastases. Delayed hypersensitivity reactions in guinea pigs were significantly increased by oral doses of 50 to 150 mg/kg. In normal rats, peripheral blood lymphocytes determined by rosette assay, were significantly increased by oral doses of 50 to 150 mg/kg of Wy-13, 251 and in a more sensitive assay using anti-theta serum the lymphocyte levels were increased by doses of 7.5 and 10 mg/kg. When cultured T lymphocytes from CBA/J mouse spleens were incubated with a suboptimal concentration of Concanavalin A, [3h]thymidine uptake was significantly increased in the presence of 0.05 to 1.0 μg per culture. These results suggest that Wy-18, 251 may have potential therapeutic value as an antimetastatic agent through its stimulation of the cellular immune system.     

Effect of an atypical adrenergic beta3-agonist, GS-332: sodium (2R)-[3-[3-[2-(3-chlorophenyl)-2-hydroxyethylamino]cyclohexyl]phenoxy] acetate, on urinary bladder function in rats.

We have developed an atypical adrenergic beta3-agonist, GS 332: Sodium (2R)-[3-[3-[2-(3 Chlorophenyl)-2-hydroxyethylamino]cyclohexyl]phenoxy]acetate, which has an unique structure compared to other beta3 agonists. In vitro study, we compared effects of GS 332 on rat urinary bladder muscle strip contractility with those of clenbuterol hydrochloride (clenbuterol), an adrenergic beta2 agonist. GS-332 relaxed isolated rat urinary bladder strips in a concentration dependent manner with 50% effective concentration (EC50) of 15.7 nM, and the relaxant activity of GS 332 was as potent as that of clenbuterol(EC50; 30.8 nM). The concentration response curve of GS 332 on isolated rat urinary bladder was competed by a specific beta3-antagonist, SR59230A in a concentration-dependent manner, in which Schild slope was 1.1 and pA2 value of SR59230A was 7.1. In vivo study, cystometory investigated in anesthetized rats demonstrated that GS 332 was more potent in increasing the urinary storage volume than clenbuterol and less potent in inhibiting the contractile force of urinary bladder at micturition reflex than clenbuterol. These data demonstrate that GS 332, a new adrenergic beta3-agonist, may be more useful to maintain continence than clenbuterol, an adrenergic beta3 adrenergic agonist.     

Mapping quantitative trait loci that regulate sensitivity and tolerance to quinpirole, a dopamine mimetic selective for D(2)/D(3) receptors

Acute sensitivity and tolerance to quinpirole (a dopamine mimetic with selectivity for D(2)/D(3) dopamine receptors) were evaluated in the C57BL/6J and DBA/2J inbred strains of mice, 24 of their BXD recombinant inbred strains, and 233 F(2) mice. Baseline locomotor activity, locomotor activity following 0.03 mg/kg quinpirole (and 0. 01 mg/kg in BXD mice), body temperature following 1 mg/kg quinpirole, and hypothermic tolerance following 2 or 3 days of quinpirole administration were evaluated. Quantitative trait locus (QTL) analysis was employed to identify genetic determinants of baseline locomotor activity and five behavioral responses to quinpirole. We examined correlated allelic variation in genetic markers of known chromosomal location with variation in each of these phenotypes. We definitively mapped a QTL on Chromosome (Chr) 9 linked to the D(2) dopamine receptor gene, Drd2, for hypothermic sensitivity to quinpirole, and identify a suggestive QTL in the same chromosomal region for tolerance to quinpirole after repeated treatments. Suggestive QTLs were also identified on Chr 19 for sensitivity and tolerance to quinpirole-induced hypothermia and for baseline locomotor activity; on Chr 15 for locomotor sensitivity to quinpirole; and on Chr 13 and 5 for baseline locomotor activity. Our results indicate that genetic differences in quinpirole sensitivity and tolerance are associated with QTLs near Drd2, and that baseline locomotor activity is associated with a suggestive QTL in proximity to the dopamine transporter gene Dat1. These data suggest that the genes influencing locomotor activity, dopamine mimetic sensitivity, and tolerance do not overlap completely.     

Synthesis of functional unsaturated polyesters using rare earth coordination catalysts, 3. Mechanistic aspects of maleic anhydride-epichlorohydrin copolymerization with Nd[(RO)2 PO2]3/Al[CH2CH(CH3)2]3 as a catalyst

Ring-opening alternating copolymerization of maleic anhydride and epichlorohydrin was carried out at 70°C with rare earth coordination catalysts composed of Nd[(RO)₂ PO₂]₃ (R = CH₃(CH₂)₃CH(C₂H₅)CH₂? )and trialkylaluminium. Anlaysis of end-groups showed that the copolymer chain contains one ? OH and one ? CH?CH? CO? CH₂CH(CH₃)₂ end-group. IR, UV-Vis, ¹H NMR and GPC results imply that a catalyst-maleic anhyride complex is formed in the initiation step that the ring-opening copolymerization proceeds via coordinate insertion mechanism accompanied with chain-transfer.     

Immunomodulatory Activity of Wy-18, 251 (3-(P-Chlorophenyl) Thiazolo [3,2-A]Benzimidazole-2-Acetic Acid)

The in vitro and in vivo effects of the experimental immunomodulatory agent Wy-18,251 (3-(p-chlorophenyl) thiazolo [3,2-a] benzimidazole-2-acetic acid) were studied in comparison with levamisole and indomethacin. Levamisole (4 mg/kg, i.v.) but not Wy-18, 251 (≤ 10 mg/kg, i.v.) enhanced carbon clearance rates in vivo in mice. Both Wy-18, 251 and levamisole (100 mg/kg, p.o.) significantly suppressed the symptoms of experimental allergic encephalomyelitis (EAE) in rats injected with spinal cord emulsion, but neither were as effective as tilorone in this model. Wy-18, 251 and levamisole (1-100 mg/kg, p.o.) suppressed the in vivo generation of plaque-forming cells (PFC) in mice immunized with sheep red blood cells while indomethacin (9 mg/kg, p.o.) enhanced PFC formation. All 3 agents (10^-5-10^-6 M) enhanced the in vitro ovalbumin (0A)-specific and Con A- or PHA-induced proliferative response and Con A-stimulated interleukin 2 (IL-2) synthesis of rat spleen cells. Furthermore, in vivo treatment of rats with 1-10 mg/kg (p.o.) of Wy-18, 251 and levamisole but not indomethacin increased the subsequent in vitro mitogen or antien (OA) responsiveness of spleen cells. None of the drugs (10^-5-10^-7 M) influenced the natural killer cell (NK) activity of rat spleen cells when incorporated directly into the ⁵¹Cr release NK assay.     

Survey during 4 years of the infestation level of the tick Ixodes ricinus (acari Ixodidae) by Borrelia burgdorferi, the agent of Lyme borreliosis, in 2 forests in Brittany]

The authors followed, during 4 years consecutively, from 1987 to 1990, by immunofluorescence, the frequency of B. burgdorferi in an amount of 677 nymphs of I. ricinus tick, collected fasting by flagging in 2 forests in Brittany (France). Percentages obtained in each of these forests do not reveal significative differencies statistically and seem to show a relative stability, from one year to the following, during the considered period, of the infestation levels in ticks.     

Chronic administration of 2-(2-benzofuranyl)-2-imidazoline (2-BFI) induces region-specific increases in [3H]2-BFI binding to rat central imidazoline I2 sites

Chronic administration of I(2) ligands increases the density of central I(2) sites as measured in brain homogenates. Here, we have used autoradiography to examine whether the increase in I(2) site density induced by chronic administration of 2-(2-benzofuranyl)-2-imidazoline (2-BFI) is uniform across brain regions. We dosed rats with 2-BFI 7 mg/kg or with saline vehicle i.p. over 96 days. Compared with vehicle-treated rats, this treatment significantly increased specific [(3)H]2-BFI binding only in the arcuate nucleus and area postrema, by 63% and 67% respectively. There were no significant effects in the pineal gland or interpeduncular nucleus which, like the arcuate nucleus and area postrema, are rich in I(2) sites. These data indicate that chronic administration of 2-BFI selectively alters radioligand binding in two I(2) rich brain ideas, namely the arcuate nucleus and area postrema, suggesting there may be more than one population of I(2) sites in the rat brain.     

Properties of poly[N-2-(methyacryloyloxy)ethyl-N,N-dimethyl-N-3-sulfopropylammonium betaine] in dilute solution

Poly[N-2-(methacryloyloxy)ethyl-N,N-dimethyl-N-3-sulfopropylammonium betaine] (1) which is an interesting polyzwitterion polymer by virtue of its “antipolyelectrolyte solution behaviour” has been prepared by free-radical initiated polymerization in aqueous solution. Isothermal fractionation was conducted at 294 K employing formamide as solvent and acetone as precipitant. Twelve fractions covering a wide range of weight-average molecular weight (215 000 ≤ M̄_w ≤ 2 070 000) were used to characterise the polymer by light scattering, membrane osmometry and viscosity measurements. The Mark-Houwink equations, established for 1 in two good solvents, 2,2,2-trifluoroethanol (TFE) and 1,0 M aqueous NaCl solution, show that the polymer has a random coil configuration and that TFE is a thermodynamically better solvent than 1,0 M aqueous NaCl solution. The random coil configuration of 1 in TFE was confirmed from the dependence of the polymer dimensions on molecular weight.