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A Siamese cat that presented clinical signs similar to those seen in humans with mucopolysaccharidoses was studied. The animal excreted increased amounts of polymeric glycosaminoglycans in the urine, consisting almost entirely of dermatan sulfate. Electron microscopy of circulating polymorphonuclear leukocytes revealed the presence of many membrane-bound lamellar inclusion bodies. Sulfate incorporation studies with cultured skin fibroblasts indicated defective glycosaminoglycan degradation. These cells showed a deficiency in arylsulfatase B activity. The disorder appears similar or identical to the Maroteaux-Lamy syndrome described in humans.

Citrullinemia-is one of several human diseases caused by a defect in the Krebs-Henseleit urea cycle. In this disorder a deficiency of liver argininosuccinate synthetase has been reported.' 1\Iorrow and his colleagues have recently described an infant with this condition2 and a fibroblast-like cell line has been derived from a skin biopsy of this child. In studying minimal media requirements for heteroploid human cell cultures, Eagle observed that citrulline, but not ornithine, could substitute for arginine as an essential nutrient.3 This evidence for the existence of the citrulline to arginine portion of the Krebs-Henseleit cycle had also been noted in cultured chick embryo heart fibroblasts.4 We have found that extracts of diploid fibroblast-like cells cultured from human skin normally can convert citrulline to arginine, but not ornithine to citrulline (ornithine transcarbamylase) or arginine to urea (arginase).5 We have compared the growth requirements and the properties of argininosucciinate synthetase in normal human cells and cells cultured from the skin of an infant vith citrullinernia. Our findings provide evidence for the genetic nature of this human disorder. Methods and Material.-Procedure for cell culture: Fibroblast-like cell lines were established from skin biopsies of human subjects and were subcultured in monolayers according to the procedure of Hayflick and Moorhead.6 Control lines were from three different human subjects and the citrullinemia cell line was derived from the skin of a 4-month-old female with citrullinemia ("citrullinemia cells"). The complete medium included 0.2 mAl arginine and was made up of 90% (v/v) double-strength Eagle's basal medium in Earle's balanced salt solution and 10% (v/v) fetal calf serum. For arginine-free medium a special preparation of Eagle's amino acid concentrate without arginine was used (Flow Laboratories, Rockville, Md.). Because the arginine-free medium contains 10% fetal calf serum, the final medium described as "arginine-free" does contain some arginine (approximately 2 JAM). Penicillin (100 units/ml), streptomycin (100 ,Pg/ml), and aureomycin (50 ,4g/ml) were added to the medium. The aureomycin was effective in pre

Although tetraploidy and tetraploid-diploid mosaicism has been well documented in studies of aborted human fetuses, no living case has been reported. This report concerns a male infant with tetraploiddiploid mosaicism who survived for 36 weeks. Because the peripheral blood cells of this infant displayed gross differences both in cell size and in DNA content, it was possible to establish that the tetraploidy observed in cultured cells was a true reflection of in vivo mosaicism.The propositus was born on December 6, 1965, after a 42-week gestation notable for a paucity of fetal movement. Birth weight was 1.7 kg, length 40.6 cm and head circumference 25.4 cm. He presented with multiple congenital anomalies. Peripheral blood smears appeared to contain two populations of neutrophilic granulocytes that differed in overall size.Immunological assessment gave the following results : 1. Serum immunoelectrophoresis performed at the ages of 4, 10 and 14 weeks showed qualitatively normal immunoglobulins. 2. Normal antibody responses were obtained to type I polio and to typhoid-paratyphoid vaccines given at age 10 weeks.3. Normal delayed hypersensitivity was obtained following stimulation with 2,4-dinitrofluorobenzene at the age of 12 weeks. There was a normal plasma growth hormone response to insulin-induced hypoglycemia at 12 weeks of age.Many of the cells in follicular centers of the spleen and lymph nodes were pale, and the lymphocytes surrounding them were bizarre, being unusually large and hyperchromatic. The histologic architecture was preserved and cortico-medullary differentiation maintained.Tetraploid-diploid mosaicism was found in ten short-term cultures of peripheral blood leukocytes obtained over a seven-month period. The average proportion of tetraploid cells was 69 % (range 64 to 77 %).Chromosomal analysis of six different primary fibroblast cultures, including that derived from the postmortem lung, were diploid in number and euploid in karyotype.Peripheral blood smears appeared to have two populations of neutrophilic granulocytes which differed from one another in their overall size. The distributions of cell diameters from all of the subject's smears showed highly significant positive skewing, in contrast to the more symmetrical distributions from the control smears.Analysis of bimodality, using a computer, indicated the presence of two normally distributed subpopulations. The,results generated are given in table IV.Cytophotometric measurements of cellular DNA content can be used to analyze tetraploid-diploid mosaicism, since tetraploid cells have twice as much DNA as diploid cells. The large cells in peripheral blood from the subject had 2.01 times the stain content of his normal appearing cells, and 1.91 times that of the control. I n order to estimate the incidence of tetraploidy among the subject's leukocytes, measurements were made on randomly selected cells a n d gave the results shown i n table V.