Purification and partial characterization of the major allergen, Cav p 1, from guinea pig Cavia porcellus.

BACKGROUND: Allergic reaction to guinea pig has been recognized as a problem in domestic settings and work environments for many years. Until recently, limited information was available on the properties of guinea pig allergen(s). In this study the major allergen Cav p 1 was characterized and the N-terminal amino-acid sequence was determined. METHODS AND RESULTS: Sera from 40 patients with IgE-mediated allergy to guinea pigs were investigated by means of immunoblotting using extracts prepared from guinea pig hair and urine. Three major allergens were identified within both sources with molecular weights (MW) of 8 kDa, 17 kDa and 20 kDa, respectively. From aqueous hair extracts the 20 kDa allergen (Cav p 1) was purified to homogeneity by anion exchange chromatography and reverse-phase HPLC and the N-terminal amino-acid sequence was determined. On the basis of the 15 residues, 57% identity was obtained from computer search with a sub-sequence of MUP (major urinary protein), a member of the lipocalin superfamily. Allergenic relationships among guinea pig allergens derived from various sources (hair and urine) or different animal species (mouse, rat, cat) were studied by ELISA inhibition assays. Neither urine of mouse, rat and cat, nor hair extracts of rat and cat produced appreciable inhibitions in guinea pig ELISA. CONCLUSION: Although the physicochemical characteristics of isolated Cav p 1 are very similar to those for other rodent allergens and furthermore partial sequence identity with Mus m 1 was found, it is clearly shown here to be an immunologically independent major allergen.

Ntau-methylhistidine excretion is a valid index of myofibrillar protein breakdown in the guineapig (Cavia porcellus).

The recovery of radioactivity in the urine of guineapigs following a bolus intravenous dose of chromatographically pure 14C-Ntau-methylhistidine was measured in order to test whether the excretion of Ntau-methylhistidine (Ntau-MH) is a valid index of myofibrillar protein breakdown in these animals. Four male and four female guineapigs were dosed and after 7 days, 91.65+/-2.82% and 3.58+/-0.91% of injected radioactivity was recovered in the excreta and tissues, respectively. The average total recovery of 95.2+/-3.0% was not significantly different from 100%. Male guineapigs excreted the radioactivity more slowly than females (70% of the dose excreted within 74 h vs 39 h, respectively) but cumulative excretion at 7 days was the same for each sex. Chromatographic analysis of the urine showed almost all of the radioactivity to be associated with a single peak corresponding to Ntau-MH, indicating a lack of significant metabolism. These data show that although the clearance of 14C-Ntau-MH is slower than in rats or humans the urinary excretion of Ntau-MH is a valid index for myofibrillar protein degradation in the guineapig.

Effect of dietary salt (NaCl) supplementation on urinary profile of guinea pigs (Cavia porcellus).

Sodium chloride supplementation (120 mg/kg of body weight/day) for 12 days increased the urinary excretion of calcium from 91.6 +/- 9.0 to 159.4 +/- 16.0 mumol/day and of sulphate from 266.8 +/- 24.5 to 1176.9 +/- 87.2 mumol/day in guinea pigs. The stone risk due to increased urinary calcium excretion could possibly be counterbalanced by increasing urinary sulphate excretion. High salt intake, thus, could not increase the risk of stone formation.

Feeding and excretion in the Afghan pika (Ochotona rufescens rufescens), a new laboratory animal.

Food and water intake and the excretion of urine and faecal pellets during the day (0500-2100) and at night (2100-0500) were observed in Afghan pikas, rats and guineapigs fed appropriate diets. Urine composition was observed in these species after they had been fed the pika diet for 4 weeks. Rats ate more at night than did pikas or guineapigs. The pikas excreted numerous small, hard faeces and soft faeces, the latter being reingested. On the pika diet all species gained about 10% in bodyweight. Food consumption was similar to that shown by each species on its own diet. All animals fed the pika diet excreted alkaline urine. Chloride concentration in pika urine was similar to that of the rat and was significantly higher than that of the guineapig. The ratio of sodium to potassium in pika urine was 2.8 and 1.7 fold that of the rat and guineapig respectively. Osmolality of pika urine was slightly higher than that of the rat, and was 3.8 fold that of the guineapig.

Chemical communication in Cavia: responses of wild (C. aperea), domestic (C. porcellus) and F1 males to urine.

Urine preferences of wild (Cavia aperea), domestic (C. porcellus), and F1 adult male guinea pigs were investigated. Males of all three types preferred female urine to male urine regardless of donor type. When given a choice between female urine of each type, males preferred conspecific urine. In choices between male urine of the three types, a conspecific preference was evident for wild and domestic but not F1 subjects. These data indicate that a loss of distinctive male and female odours had not occurred as a result of domestication. However, the urine odours of wild and domestic types have diverged. The possible effects of previous individual experience on the preferential response is discussed.