We report on two patients with mosaic tetrasomy of 8p[46,XY/47,XY,+i(8p)], a previously unreported cytogenetic anomaly. The first patient had a low percentage of tetrasomic (secondary trisomic) cells in lymphocytes and fibroblasts, an only mildly abnormal phenotype, and a rather benign clinical course. The second patient had a considerably larger percentage of tetrasomic cells in lymphocytes and fibroblasts, and had more severe congenital anomalies that led to his death at 8 months. A characteristic phenotype +i(8p) is suggested but not yet established. The manifestations of these two patients resemble those of mosaic trisomy 8 and mosaic trisomy 8p, with rib and vertebral abnormalities, absent corpus callosum, and enlarged cerebral ventricles.

The frequency of sporadic, hypermodal chromosomal spreads in cultures of leukocytes taken from the parents of aneuploids significantly exceeds that in comparison populations. Elimination of other possibilities suggests mitotic nondisjunction as the ultimate determinant for such spreads. This possibility requires that more attention be paid to the occurrence of hypermodal spreads, especially relative to the etiology of aneuploid concepti.

In cystic fibrosis (CF) ~a t i e n t s Na reabsorption from the primary secretions of exocrine glands is markedly reduced. Because the ducts of rat salivary glands have Na reabsorptive activity levels second only t o the kidney tubule and can be inhibited by a component of CF exocrine secretions, they provide a good system for studying factors which alter ion transport in exocrine glands. We found .that male rats (n=IO) from two different Sprague-Dawley lines (designated OU and S1) produced parotid salivas with intrinsically different Na contents (e.g. 90 vs 30 mEq/L) when induced t o salivate with pilocarpine. Serum Na levels were indistinguishable from one another. Crosses between OU and SI lines produced F1 males (n=12) with parotid Na levels which were intermedia t e to either parent. Reciprocal crosses gave identical results, i.e. the relative activity of the ductal Na transport system was controlled by a single pair of incompletely dominant autosomal alleles. Reserpineinduced inhibition behaved a s a simple dominant. Three daily doses of reserpine had no effect on the Na content of F l progeny or the SI line but elevated the Na content of the OU line. Backcrosses of F l progeny t o each parent line produced males (n=IO) with phenotypes of the F1 hybrid and the appropriate parental type, again, consistent with a single gene autosomal recessive mode of inheritance of the low Na transport capacity phenotype. This gene appears t o control a component of the ductal Na transport system which is sensitive t o the humoral inhibitor induced by reserpine administration. DIFFERENCES IN PAROTID SALIVA SODIUM LEVELS 71;fi AND RESERPINE-RESPONSIVENESS BETWEEN RAT' VV LINES. Thomas W. Seale, Barbara H. Farber, and Owen M.Rennert. Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma Citv, Oklahoma.The mechanism underlyingethe inhibition of Na reabsorption from exocrine secretions in cystic fibrosis (CF) is not known. In the animal C F phenocopy of Martinez, chronic reserpine (RS) administration t o rats causes histological and physiological changes in exocrine glands similar t o those in CF. To examine the effect of chemical sympathectomy on Na transport, we studied the onset of inhibition of Na reaborption from parotid saliva in male Sprague-Dawley (SD) rats given i.p. RS (0.5 mg/kg) daily. Saliva stimulated by i.p. pilocarpine was collected by cannulating the parotid duct. A single RS dose caused a marked increase in Na content within 24 hr in rats from our colony (OU). Na content increased linearly with the duration of RS administration. Saliva of SD rats from Sasco Inc. 61) contained much less Na than that of OU rats a t all saliva flow rates below 70 ul/min/g gland wet weight. RS administered t o SI rats caused no demonstrable increase in saliva Na content until the 4th day. Na increased only t o levels seen in untreated OU rats. These results indicate that both the intrinsic activity and the susceptibility t o inhibition of the ductal Na transport system of exocrine glands show specific ...