The relationship between structural features of peripheral nerves and suture methods for nerve repair

Based on techniques for identifying and distinguishing motor, sensory, and mixed fasciculi in peripheral nerves, the authors propose guidelines for selecting suture methods for nerve repair. When many mixed fasciculi are known to exist at the nerve lesion, epineurial repair is preferable; fascicular (perineurial) repair is more suitable when pure motor and sensory fasciculi are clearly recognized. Generally, epineurial repair is indicated for more proximal injuries, with fascicular repair most appropriate for more distal sites. A greater ratio of epineurial connective tissue to intrafascicular nervous tissue implies an inclination toward fascicular repair.

The effect of progestin on rabbit endometrial aromatase activity

The ability of rabbit endometrium to synthesize estrogen was investigated. Aromatase activity was measured by incubating the viable tissue fragments with [3H] testosterone at 37 degrees C and quantitated the [3H]estrogens at the end of 6 h incubation. The activity was not detectable in endometrium and myometrium of non-pregnant rabbits. In pregnant rabbit, the activity increased from 2 to 12 fmol/h/g of tissue in endometrium obtained from both gravid and nongravid uterine horns 4-8 days after mating. Aromatase activity in endometrium at implanted sites on the 8th day after mating reached up to 550 fmol/h/g of tissue. Hormonal regulation of the aromatase activity was studied directly in cultured rabbit endometrial stromal cells. Both progesterone and medroxyprogesterone acetate stimulated the activity with 2- to 25-fold increase over the control values (0.2-1 fmol/h/mg protein). The stimulation of aromatase activity by progestin was found to be both time- and dose-dependent. Estrogen, Bu2cAMP, forskolin, HCG or relaxin had no effect on the activity. Aromatase activity in glandular epithelial cells was neither detectable nor affected by progestin. These results indicate that aromatase activity in rabbit endometrium is concentrated in stromal cells and progestin stimulates the activity. However, estrogen, forskolin and relaxin which enhanced the stimulation of the activity by progestin in human endometrium had no effect on aromatase in rabbit endometrium. The increase of aromatase activity observed after the onset of conception may be physiologically important to increase the local estrogen content for decidualization of the endometrium.

Anatomical analysis of the cause of skin necrosis of the great toe after transplantation of the great toe nail flap

Necrosis of skin on the medial side of the great toe has been a significant complication of the great toe nail flap. To investigate the reason for this, a study of the blood supply of the medial side of the great toe was carried out on 55 feet with the injection of red latex into the arteries and on 13 vascular cast specimens. It was found that, after the blood vessels from the plantar and dorsal sides of the great toe are severed during the operation, the skin of the medial side of the great toe is mainly supplied by the medial vascular network at the head of the first metatarsal bone. It is clear that the blood supply from this network may sometimes be insufficient to nourish the skin. It is suggested that the operative incision should be changed so as to increase the blood supply to the medial vascular network which may decrease the incidence of skin necrosis.

Endocrine aspects of human uterine sarcoma: a preliminary study

The biologic effect of estrogen and progesterone in human uterine sarcoma is poorly understood in comparison to that of endometrial adenocarcinoma. In an attempt to elucidate the endocrine status of these tumors, we have investigated the ability of these tumors to synthesize estrogen by measuring the aromatase activity and studied the effect of aromatase inhibitors on the activity. In addition, the effect of estrogen and progesterone on aromatase activity and the growth pattern of these tumors were studied in cell culture and athymic mice systems. Aromatase activities in eight uterine sarcomas ranged from 0.7 to 37 fmol/hr X mg protein, which were within the range or higher than the activity found in normal proliferative endometrium (0.5 to 3 fmol/hr X mg of protein, means = 1.6, n = 10). These results indicate that uterine sarcomas are capable of producing estrogen. However, the enzyme activity showed no correlation with the morphology of tumors or the age of patients. Results from the kinetic studies of aromatase activity in one of the uterine sarcomas indicated that 19-nortestosterone, testolactone, and aminoglutethimide (the most effective one) inhibited aromatase activity. In addition, induction of aromatase activity in two uterine sarcomas was investigated in cell cultures. Progesterone caused an eightfold increase in activity in a sarcoma that was estrogen and progesterone receptor positive but had no effect in a tumor that was estrogen and progesterone receptor negative. The growth rate of two estrogen/progesterone receptor-negative uterine sarcomas was studied in cell culture and in athymic mice. Progestin, but not estrogen, reduced the growth rate in both systems; 30 nmol/L of estrogen had no effect on the growth rate. In summary, we have found that human uterine sarcoma is able to synthesize estrogen. Progesterone is able to induce the aromatase activity in estrogen/progesterone receptor-positive tumors, and progesterone also suppresses the tumor growth rate in estrogen/progesterone receptor-negative tumors. These results suggest that a select group of uterine sarcomas is sensitive to steroid hormone and that progesterone may be potentially beneficial for therapeutic treatment of select uterine sarcomas.

Modulation of aromatase activity in human endometrial stromal cells by steroids, tamoxifen and RU 486

The regulation of aromatase activity (AA) in human endometrial stromal cells by various steroids was studied in primary cell culture. Various progestins, but not androgens or glucocorticoids, stimulated AA. Medroxyprogesterone acetate (MPA) was the most potent progestin. Estrogen (E) alone did not change the activity but it potentiated the stimulation of AA by progestin. Biphasic regulation of AA by progestin was noted in both time- and dose-dependent manners. Endometrial AA was stimulated by MPA and reached the maximum rate between 2-5 days of incubation with subsequent decline of AA in prolonged culture. When stromal cells were treated with MPA (0.03 to 30 microM) for 3 days, AA was increased over the control at all the concentrations tested. The maximum was found at doses between 0.1-1 microM. The activities reduced steadily from the maximum stimulation to less than 50% when the concentration of MPA increased from 1-30 microM. In addition, initial treatment of stroma cells with MPA (1-3 days) resulted in further increase of activity after progestin withdrawal. The enhancement of the induction of AA by E did not alter the biphasic pattern regulated by progestin alone, i.e. E enhanced both the stimulation and the decay of AA. The time study of the effect of E showed that enhancement of AA required at least 10 h of incubation of E with MPA conditioned cells. The effect of E is dose dependent between 0.04-40 nM and shows the greatest effect in the presence of MPA between 0.01-1 microM. The optimal concentrations of E and progestin that stimulate AA in culture are similar to the plasma concentrations after pregnancy, suggesting that the physiological function of the endometrial aromatase is at the time of decidualization. The effects of antiprogestin, Ru 486, and antiestrogen, tamoxifen (TAM), on AA were studied. Ru 486 or TAM alone did not alter AA. Ru 486 inhibited the MPA stimulated AA in a dose-dependent manner suggesting that the effect of progestin may be mediated through a receptor mechanism. Enhancement, but no inhibitory effect, was observed when cells were treated with TAM + MPA and TAM + MPA + E. The effectiveness of Ru 486 to inhibit the induction of AA in endometrial cells may be of primary importance for contraception.