The effects of dietary calcium (Ca) concentration and calcium: phosphorus (Ca:P) ratio on mineral balance and nephrocalcinosis were studied in female rats. In the first experiment there were two dietary Ca concentrations (0.25 and 0.50%, wt/wt) at two different Ca:P ratios (0.6 and 1.3). In the second experiment the diets were formulated to contain 0.40% P and either 0.13, 0.25, 0.50 or 0.75% Ca. The diets contained 0.03% magnesium (Mg). The fecal outputs of Ca, P and Mg were lower (P less than 0.01) after feeding low Ca diets than after feeding high Ca diets. Urinary excretion of P decreased with increasing dietary Ca and increased with increasing P intake. In rats fed the 0.25% Ca diets whole-body retentions of Ca and P were lower than in the rats fed 0.50% Ca. Both increases in dietary Ca from 0.13 to 0.50% and P from 0.20 to 0.40% elevated Ca and P content of kidneys as well as the degree of nephrocalcinosis. However, after feeding the highest Ca concentration (0.75%) nephrocalcinosis was essentially absent while kidney concentrations of Ca and P were relatively low. When compared with 0.50% Ca in the diet, 0.75% Ca increased group mean whole-body retention of Ca but lowered that of P. In individual rats the degree of nephrocalcinosis and the concentrations of minerals in kidney were positively correlated.

A cultured microflora obtained from the caecum of a 'normal' mouse was given to 4 groups of germfree mice and was supplied 1x, 2x, 3x and 4x respectively at 5-day intervals. Another group received a 10-7 dilution of the caecal flora while a group associated with an 'SPF' flora served as control. The difference (measured by 8 parameters) between mice supplied with the cultured flora or with a 10-7 dilution, both given once only, was small. Supplying the flora 3x resulted in more 'normal' mice compared with mice which received the flora once or twice. The caeca of specified-pathogen-free mice contained more bacteria per gram (microscopic bacterial count), less aerobic and anaerobic bacteria per gram (viable counts), while the yield as percentage of the microscopic bacterial count was lower as compared with the group to which a cultured flora was supplied 4 times.

Germfree (GF) mice were inoculated with a cultured flora from 10-1, 10-3, 10-5, and 10-7 dilutions of caecal contents from a 'normal' mouse. GF mice associated with a flora of a 'normal' mouse served as controls. The following intestinal parameters were determined: Colonization resistance (CR), Relative caecal weight (RCW), villus:crypt ratio (jejunum and ileum), IgA-producing cells (jejunum and ileum), ß-aspartyl glycine (faeces), volatile and non-volatile fatty acids (caecum) and bile acids (faeces). Only the 10-1 culture was able to induce similar changes in the GF mice to a 'normal' flora. The GF + 10-5 and GF + 10-7 groups deviated markedly from the controls while the GF + 10-3 group showed in general intermediate values between GF + SPF and GF + 10-1 on the one hand and GF + 10-5 and GF + 10-7 on the other hand. ß-aspartyl glycine was present only in the GF + 10-7 group. Scanning electron microscopy (SEM) of ileal contents revealed segmented filamentous organisms in the ileum of controls and the GF + 10-1 group. The faecal flora consisted mainly of fusiform organisms. In the faeces of the 10-5 and 10-7 groups increasing amounts of non-bacterial matter were found, while in the faeces of the other groups virtually only bacteria were seen.

In 2 gulneapigs umbilicated tumours localized in the subcutis were diagnosed as trichofolliculomas. Histopathological examination revealed easily recognizable groups of abortive hair follicles arranged around a complex central space. A 3rd case was a sebaceous gland adenoma, also situated in the subcutis.

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