Prenatal diagnosis and clinical features of an individual with tetrasomy 18p and trisomy 18q mosaicism

Prenatal diagnosis and clinical follow up of a patient with mosaicism for anomalies of chromosome 18 are reported. The fetus appeared on ultrasound to have multiple anomalies, including clubbed feet, abnormal hand positioning, edema of the scalp, cleft palate, and polyhydramnios. The karyotype on amniocytes was 47,XY,+i(18p). Postnatally, the peripheral blood karyotype was 46,XY,+i(18q), whereas the skin fibroblast karyotype was 47,XY,+i(18p). The infant had many features consistent with those previously described in cases of tetrasomy 18p and some that were consistent with trisomy 18q.

Hairless pigmented guinea pigs: a new model for the study of mammalian pigmentation

A stock of hairless pigmented guinea pigs was developed to facilitate studies of mammalian pigmentation. This stock combines the convenience of a hairless animal with a pigmentary system that is similar to human skin. In both human and guinea pig skin, active melanocytes are located in the basal layer of the interfollicular epidermis. Hairless albino guinea pigs on an outbred Hartley background (CrI:IAF/HA(hr/hr)BR; designated hr/hr) were mated with red-haired guinea pigs (designated Hr/Hr). Red-haired heterozygotes from the F1 generation (Hr/hr) were then mated with each other or with hairless albino guinea pigs. The F2 generation included hairless pigmented guinea pigs that retained their interfollicular epidermal melanocytes and whose skin was red-brown in color. Following UV irradiation, there was an increase in cutaneous pigmentation as well as an increase in the number of active epidermal melanocytes. An additional strain of black hairless guinea pigs was developed using black Hr/Hr animals and a similar breeding scheme. These two strains should serve as useful models for studies of the mammalian pigment system.

Calcium and phosphorus metabolism during total parenteral nutrition

Calcium and phosphorus metabolism and balance were studied in 151 patients receiving total parenteral nutrition (TPN). Hypercalciuria was common, with mean (+/- SD) urinary calcium excretion 17.5 +/- 3.9 meq/24 hours (n = 2610). There was a significant positive correlation between urinary calcium excretion and parenteral calcium intake (r = 0.34, p less than 0.001). There was also a positive correlation between calcium balance and parenteral calcium intake (r = 0.61, p less than 0.001) in patients without extra-renal losses. Positive calcium balance was achieved with parenteral calcium intake greater than 15 meq/24 hours. Urinary phosphorus excretion correlated positively with parenteral phosphorus intake (r = 0.50, p less than 0.001). Phosphorous balance also correlated positively with parenteral phosphorus intake (r = 0.78, p less than 0.001). Positive phosphorus balance was achieved with parenteral phosphorus intake above 15 mmol/24 hours. Fifty-three patients received 1,000 IU vitamin D once weekly and showed no significant change in serum calcium. Ninety-eight patients received 1,000 IU vitamin D twice weekly and showed a gradual but significant mean increase over time in serum calcium.

Clinical response of dermatitis herpetiformis skin lesions to a gluten-free diet

Patients with dermatitis herpetiformis have been studied prospectively for 2 years to assess the effect of a gluten-free diet (GFD) on control of the skin lesions. Daily requirements for oral medication with sulphapyridine or dapsone were reduced by GFD treatment and if complete clinical remission of the skin disease occurred, it was maintained while the diet was strictly observed. However, complete remission did not occur significantly more often in GFD-treated patients than in patients taking a normal diet. Many of the latter group exhibited variation in their drug dose requirements during the period of study. GFD treatment seems desirable for the majority of patients with dermatitis herpetiformis, not only to correct the intestinal abnormality but also to minimize the dose of drugs necessary to control the skin lesions.