Significance of arginase and ornithine in malignant tumors of the human skin.

During neoplastic development, several aspects of the regulation of polyamine synthesis undergo profound changes. In extrahepatic mammalian tissues in which the urea cycle is not functioning, arginase is believed to supply the cell with ornithine, a non-protein amino acid that is a precursor for biosynthesis of polyamines. Because the activity of ornithine decarboxylase and polyamine levels have been shown to be elevated during carcinogenesis, we decided to investigate the role of arginase in the development of malignant tumors of the human skin and to examine whether arginase activity and ornithine level can be used as biologic markers for distinguishing patients with squamous cell cancer from patients with basal cell cancer. For this purpose, we studied tissue arginase activity and ornithine level in tumor and adjacent normal tissues in 16 patients (55 +/- 10 years of age) with malignant skin tumors (8 of which were squamous cell cancers and 8 of which were basal cell cancers). The mean arginase activity and ornithine levels in tumor tissues (total) were 17.75 +/- 8.54 U/mg protein and 40.89 +/- 14.88 nmol/mg protein, respectively, versus 3.69 +/- 1.71 U/mg protein and 12.98 +/- 6.21 nmol/mg protein, respectively, for normal tissues. The mean specific arginase activity levels in squamous cell and basal cell cancers of the human skin were 18.49 +/- 10.47 U/mg protein and 16.63 +/- 6.00 U/mg protein, respectively. The mean ornithine levels in squamous cell and basal cell cancers of the human skin were 42.45 +/- 19.10 nmol/mg protein and 39.33 +/- 10.19 nmol/mg protein, respectively. Our results indicated that (1) arginase activity and ornithine levels are elevated in squamous cell and basal cell cancers of the human skin; (2) the increased activity of arginase and hence the elevated levels of ornithine may be important in the development of malignant tumors of the human skin; and (3) although arginase activity and ornithine level may be useful for distinguishing patients with malignant skin tumors from healthy subjects, they cannot be used as biologic markers for distinguishing patients with squamous cell cancer from patients with basal cell cancer.

A left transverse facial cleft with a median cleft of the lower jaw.

OBJECTIVE: A 13-day-old girl with a left transverse facial cleft and a median defect of the lower jaw is reported in detail. Left macrostomia was repaired using a W-plasty technique, and preauricular appendages were excised. The median defect of the mandible demonstrated by computed tomography scan on the first examination had disappeared at 1 year of age. CONCLUSION: Congenital clefts of the mandible can fuse at a later stage; thus, it is necessary to wait to treat the mandibular defect until the infant is slightly older.

Vascular effects of epinephrine, lisinopril, and chlorpromazine in diabetic and non-diabetic rats.

In this study, the vascular responses of diabetic rat femoral arteries to epinephrine were investigated. The effects of lisinopril (ACE inhibitor) on vascular epinephrine sensitivity were also tested in a different group. This study was carried out in sodium pentobarbital-anesthetized rats 8 weeks after induction of diabetes with streptozotocin. After extensive dissection of the femoral arteries with adventitial stripping, epinephrine and chlorpromazine were applied to the vascular wall, and their vascular effects were compared in streptozotocin-diabetic (STZ-D), lisinopril-administered streptozotocin-diabetic (LASTZ-D), lisinopril-administered nondiabetic (LAND), and non-diabetic (ND) groups. Vasoconstriction was induced by epinephrine in all groups in a dose-response fashion. There were statistically significant differences in maximum percent constriction between STZ-D and LASTZ-D groups. There was also a significant increase in sensitivity to epinephrine in the STZ-D group. The vasoconstriction induced by epinephrine was relieved by chlorpromazine in all groups. Results suggest that there are important functional abnormalities in the responses of vessels to epinephrine in diabetics, and that the attenuation of vasoconstriction by ACE inhibitors may have beneficial effects in microsurgical procedures performed on diabetic patients. Topically-applied chlorpromazine appears to be effective in relieving vasospasm due to epinephrine, and may be a useful tool to resolve perioperative vascular spasm in microsurgical procedures for diabetic and non-diabetic patients.