The amylase complex on mouse chromosome 3 encodes both salivary and pancreatic amylase. It appears that one active gene is present for salivary amylase, whereas pancreatic amylase in some strains is coded by at least 4, and perhaps by more than 10, genes. Strain YBR is different from other strains in that it produces twice as much salivary amylase. Pancreatic amylase in YBR is present as two different protein forms, A beta and B beta, the sum of which amounts to only one-third of that in, for instance, strain A/J. YBR chromosomal DNA was cloned in phage gamma, followed by restriction and heteroduplex analysis of recombinant phages carrying amylase genes. Among 32 phage isolates, 5 carried parts of the salivary amylase sequence. The remaining phage isolates contained pancreatic amylase-like sequences and represented three nonoverlapping genomic regions, i.e., one of 34 kb containing a complete gene, PAN-II beta; another of 41 kb with a complete but different gene, PAN-I beta, plus a truncated gene, PAN-psi 1; and finally, one of 23 kb with another truncated gene, PAN-psi 2. Parts of the amino acid sequence of A beta and B beta have previously been determined, and we report here the sequencing of a 4-kb DNA fragment from Pan-II beta which establishes that this gene codes for B beta.

Eight patients were examined. Seven had verified rhinorrhoea and six had had one or more episodes of pneumococcal meningitis. In four of the patients a fistula could not be visualized by computed tomography. All eight patients had injections of iodine-123-labelled albumin by lumbar puncture. Tomoscintigraphy (SPET) was performed 3, 6 and 8-9 h after injection. After 6-8 h we were able to demonstrate a fistula in seven of the patients with verified rhinorrhoea and the findings were confirmed by a subsequent operation. In one of the patients we were not able to visualize any leak of cerebrospinal fluid into the nasal cavity. This patient was not operated upon and we were not able to verify the findings in this patient. The operated patients all did well after the operation with no relapse of meningitis. In conclusion, SPECT-cisternography after intralumbar injection of iodine-123-labelled albumin is a valuable diagnostic tool for the detection of small fistulae in patients with rhinorrhea.

Several investigated bank vole populations are polymorphic for the number of salivary amylase loci, and individual chromosomes may carry one, two or three linked amylase structural genes. In the present study, we have used bank vole stocks homozygous for different chromosomes to investigate the relationship between amylase production and gene number. By measuring the amylase activity in parotid glands and the percentage of amylase protein in saliva, we have been able to demonstrate that the amount of salivary amylase is directly proportional to the proposed gene number. The paper also describes the allele, Amysu, which codes for a heat-labile salivary amylase. The relative amounts of the heat-labile isozyme have been determined in different hetero-zygotes containing this allele, and these results also support the multiple locus model. Finally, a stock devoid of salivary amylase activity was established. Animils from this strain have, however, a protein in the parotid glands and in saliva that is very similar to amylase in molecular weight, amino acid composition and in its binding to glycogen and cyclohepta-amylose. In genetic crosses, the protein segregates as an amylase allele. Therefore, this protein, encoded by the functionally null alleleAmyN, may represent an incorrectly processed amylase precursor.