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.

Assessment of tissue viability after frostbite injury by technetium-99m-sestamibi scintigraphy in an experimental rabbit model.

Frostbite causes injury to the tissue by direct ice-crystal formation at the cellular level with cellular dehydration and microvascular occlusion. Muscle that initially appears viable on reperfusion may subsequently become necrotic because of microcirculatory collapse. Since muscle is a sensitive tissue in frostbite injury, we used technetium-99m-sestamibi limb scintigraphy to assess tissue viability in an experimental rabbit model. Twelve rabbits were used for this investigation. The right hind limb of the rabbits was immersed to the ankle joint in a container filled with 90% ethanol at -25 degrees C for 10 min. Frostbitten limbs were allowed to thaw in air at room temperature. Imaging and pathological examination of the affected limbs were performed 2 h, 24 h, 48 h and 72 h after freezing. In 2-h images, initial hypoperfusion was seen that corresponded to circulatory collapse. In 24-h images, there was hyperperfusion (so-called period of temporary reperfusion), corresponding to circulatory restoration. In 48-h images, a second hypoperfusion corresponded to viable but ischaemic tissue. In 72-h images, there was non-perfusion of the limb that correlated with the pathologically determined diagnosis of necrosis. All scintigraphic patterns correlated with pathological findings. We suggest that these scintigraphic patterns in soft tissue may be helpful in distinguishing between frank infarction and reversible ischemia and therefore may be useful in selecting early therapeutic or surgical interventions to salvage bone and soft tissue. Further studies are needed to show the usefulness of 99mTc sestamibi scintigraphy in clinical frostbite cases.

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.

Lymphangiosarcoma in chronic lymphoedema. Stewart-Treves syndrome.

A case of post-mastectomy lymphangiosarcoma is reported. Lymphangiosarcoma is an extremely rare but highly lethal complication of chronic lymphoedema. Our patient was treated by amputation and died 6 months later. Treatment of post-mastectomy lymphangiosarcoma is still unsatisfactory. Early recognition and radical ablative surgery seem to provide best chance for survival.

Z-plasty and microvascular anastomosis.

An experimental study in rats was designed to determine the effects of z-plasty on the patency of microvascular anastomosis. Eighty Sprague-Dawley rats of mixed sex were divided into two groups. In all animals, the left carotid arteries were used. In the first group (n = 40), a single z-plasty was done at the anterior side of the carotid artery before end-to-end anastomosis was performed. In the second group (n = 40), end-to-end anastomosis with interrupted sutures was done. Patency and the appearance of the anastomosis were evaluated 1 hr later, on the seventh postoperative day, and at the end of the third postoperative week. There was no vasospasm demonstrated in the first group. Patency rates were 100 percent for both groups after 1 hr. On the seventh postoperative day, one anastomosis in the first group (patency rate, 97.5 percent) and two anastomoses in the second group had failed (patency rate, 95 percent). Patency rates were similar at the third week. The difference was not statistically significant (p = 0.5). Histologic examinations demonstrated that z-plasty did not cause any adverse effects at the vessel wall or at the anastomosis.