Post-mortem preservation of the small intestine

Gut intraepithelial lymphocyte counts in neonates, infants and children

Intraepithelial lymphocyte (IEL) counts were histologically assessed in the jejunum, ileum and appendix of 39 neonates (0-28 days), 32 infants (1-9 months) and 13 children (1-9 years). Small intestinal mucosa samples were obtained from 73 autopsies, and from 8 surgical and 3 aspirative biopsies. IEL counts of specimens from the jejunum, ileum and appendix gave similar results in the same patient. The number of IEL counts was significantly lower in neonates for all three segments. The difference between infants and children was more marked in the jejunum than in the ileum, although this was not significant. In the appendix, there was no difference between the different age groups. Our results indicate that postnatal expansion of IEL occurs homogeneously along the gut after the neonatal period.

Antibiotic-resistant mutants of Bacillus subtilis conditional for sporulation

Among spontaneously occurring antibiotic-resistant mutants of Bacillus subtilis 168 we have identified a sub-class that is conditionally sporulative. Mutants in this sub-class are resistant to antibiotic during vegetative growth but are sensitive during sporulation. Mutants conditionally-resistant to erythromycin, kanamycin, spectinomycin, and streptomycin have been isolated and characterized by phase contrast microscopy and with respect to their ability to synthesize heat-resistant endospores or the sporulation-associated enzyme alkaline phosphatase. The results suggest that several entirely different genetic lesions may result in this single phenotype. This group includes mutants whose properties suggest that both th 30S and 50S ribosomal subunits may be altered concomitant with early spore specific metabolism. The blockage imposed by antibiotic may be at or near Stage 2 of sporulation.