Recent studies suggest that the serum level of Type III procollagen (PC-III) could be a valuable, noninvasive monitor of hepatic fibrogenesis. We have developed a sensitive and specific radioimmunoassay for PC-III procollagen isolated and purified from fetal goat skin which shows high cross-reaction for human PC-III. In a double-blind study, serum samples taken from 8 normal volunteers and 50 patients at the time of liver biopsy were assayed for PC-III. Each biopsy was reviewed without knowledge of the radioimmunoassay results, and old or active fibrosis was graded on a 0 to 3 (none, minimal, moderate, severe) scale. There was a significant difference between serum concentrations of PC-III in normals (mean +/- S.D. = 72 ng per ml +/- 8) as compared to patients with biopsy evidence of active fibrosis (mean +/- S.D. = 153 ng per ml +/- 12; p less than 0.001). The serum concentration of PC-III showed a good correlation (r = 0.58; p less than 0.001) with the histological grade of active lobular fibrosis. Measurement of PC-III is a noninvasive test for detection of active fibrosis in the liver.

Double-Blind Method↗

PubMedDate not supplied

The effect of a lectin from the venom of the snake, Bothrops jararacussu, on tumor cell proliferation.

Lectins have been used extensively as histochemical probes to describe changes in tumor cell surface and are known to influence the growth of cancer cells. In this study, we determined the effect of a lectin from the venom of Bothrops jararacussu (BJcuL) on the proliferation of a number of established human cancer cell lines. The growth of eight cancer cell lines was inhibited in a dose-related manner in the presence of BJcuL lectin. This lectin was most potent as an inhibitor of growth in renal (Caki-1 and A-498) and pancreatic (CFPAC-1) cancer cell lines with 50% inhibitory concentrations (IC50) of 1-2 mM. Melanoma (Wm115) and prostate (PC-3) cancer cells showed IC50 values of 7.9 and 8.5 mM, respectively, in the presence of BjcuL lectin whereas colon (Caco-2) and breast (MCF7) cancer cell lines showed no effect. Our results suggest that BJcuL lectin is an effective inhibitor of cell growth in some cancer cell lines.

Breast Neoplasms↗

PubMedDate not supplied

Inhibition of angiogenesis by aurintricarboxylic acid.

The triphenylmethane derivative, aurintricarboxylic acid (ATA), but not aurin, is a potent inhibitor of angiogenesis in the chick chorioallantoic membrane. ATA alone showed potent anti-angiogenic activity in a dose-related manner. The presence of heparin or bFGF decreased the anti-angiogenic activity of ATA. ATA also potentiated the anti-angiogenic activity of the angiostatic steroids, cortisol-21-phosphate, 17 alpha-hydroxyprogesterone, tetrahydrocortisol, tetrahydrocortexolone and medroxyprogesterone acetate. These results indicate that ATA is a potent inhibitor of angiogenesis and potentiates the activity of the angiostatic steroids. These novel findings with this negatively charged, nonsulfated aromatic compound may be the basis for important new therapeutic approaches for the diseases of neovascularization.

Allantois↗

PubMedDate not supplied

Acute immobilization stress disrupts testicular steroidogenesis in adult male rats by inhibiting the activities of 17 alpha-hydroxylase and 17,20-lyase without affecting the binding of LH/hCG receptors.

We have investigated the effect of acute immobilization (3 hours) stress on testicular steroidogenesis in the adult rat. Immobilization did not alter plasma luteizing hormone (LH) levels, but plasma testosterone (T) levels were reduced by 82%. Plasma levels of corticosterone in stressed rats were elevated more than ninefold over control levels. After 3 hours of stress, testicular levels of progesterone were elevated 33%, and levels of 17 alpha-hydroxyprogesterone and T were reduced 47% and 37%, respectively, compared to controls. Immobilization for 3 hours had no effect on the association or dissociation rate constants of LH/human chorionic gonadotropin (hCG) receptors of testicular interstitial cells and did not alter specific hCG binding. The effect of 3 hours of immobilization on testicular 17 alpha-hydroxylase and 17,20-lyase was assessed by incubating testicular microsomes from stressed and control animals in the presence of 21[14C]progesterone and [3H]17 alpha-hydroxyprogesterone. Immobilization of rats reduced the Vmax values of 17 alpha-hydroxylase and 17,20-lyase by 47% and 48%, respectively, but had no effect on the Km values. These results support the hypothesis that stress for 3 hours disrupts rat testicular steroidogenesis via a mechanism that is independent of changes in circulating levels of LH and the binding characteristics of LH/hCG receptors. The effects of immobilization on the content of testicular steroids and on the activities of 17 alpha-hydroxylase and 17,20-lyase suggest that stress inhibits the activities of both 17 alpha-hydroxylase and 17,20-lyase.

Aldehyde-Lyases↗

PubMedDate not supplied

Androgen UDP-glucuronyl transferase activity is found primarily in liver in the rat.

UDP-glucuronyl transferase (UDPGT) activity was determined for androgens in tissue minces and microsomal fractions from the liver and extrahepatic tissues (kidney, skin, prostate, and preputial glands) of the male rat. Liver microsomes showed the highest UDPGT activity with each of the androgens tested (Vmax = 7, 3, and 10 nmol/minute/mg protein for testosterone, androsterone, and androstanediol, respectively). UDPGT activity (Vmax) for androstanediol in the liver was 10(2)-fold higher than in the kidney and 10(3)-fold higher than in the skin and prostate. UDPGT activity for androgens was not detected in microsomes from preputial glands. Furthermore, no body site distribution was found for androgen UDPGT activity in skin microsomes. The Michaelis-Menten constant (Km) for UDPGT in liver microsomes was 20.4, 12.2, and 2.2 microM, respectively, for testosterone, androstanediol, and androsterone. Kidney microsomes showed a Km of 19.4 and 26.9 microM, respectively, for androstanediol and androsterone. The Km for testosterone was very high in the kidney (138 microM), suggesting that it was a poor substrate. In microsomes from the skin and prostate, the Km was very high (range 43-162 microM) for all three androgen substrates, suggesting that these androgens were not the preferred substrates for UDPGT in these tissues. These results indicate that the liver was the main site of androgen UDPGT activity and the skin and prostate formed little, if any, androgen glucuronides. These results suggest that androstanediol glucuronide was formed primarily in the liver and may not be a reliable marker of peripheral androgen metabolism.

Androstenediols↗

PubMedDate not supplied

Antiestrogens inhibit endothelial cell growth stimulated by angiogenic growth factors.

We have previously reported that the partial estrogen antagonists, tamoxifen, clomiphene and nafoxidine, inhibited angiogenesis in vivo in a dose-related manner in the six-day old chick egg chorioallantoic membrane (CAM) assay. In the present study, we investigated the effect of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) on the growth of porcine pulmonary artery and human dermal microvascular endothelial cells. Both of these growth factors significantly increased the growth of these cells. The antiproliferative activity of the partial antiestrogens, tamoxifen, nafoxidine and clomiphene, and the pure antiestrogen, ICI 182,780, was determined. Tamoxifen, clomiphene, nafoxidine and ICI 182,780 significantly inhibited endothelial cell growth stimulated by bFGF and VEGF. This inhibition of endothelial cells was not altered by the presence of up to 30 microM of estradiol-17 beta. These results indicate that the antiangiogenic action of the antiestrogens does not occur via the estrogen receptor, but by a direct inhibition of growth factor stimulated endothelial cell growth.

Animals↗

PubMedDate not supplied

Androgen UDP-glucuronyl transferase activity is found primarily in the liver in the human.

In this study, androgen UDP-glucuronyl transferase (UDPGT) activity was determined in microsomes of human liver, skin, and prostate. Androgen UDPGT activity was highest in the liver microsomes using 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha DIOL), androsterone (AN) and dihydrotestosterone (DHT) as substrates. The Km and Vmax values and enzyme velocity at the physiological concentration of the substrates in the liver microsomes were similar for AN and 3 alpha DIOL. The values for AN were as follows: Km = 16.9 microM, Vmax = 3.77 nmol/min/mg protein, and UDPGT velocity = 0.62 pmol/min/mg protein. The values for 3 alpha DIOL were as follows: Km = 16.0 microM, Vmax = 5.61 nmol/min/mg protein, and UDPGT velocity = 0.42 pmol/min/mg protein. Androgen UDPGT activity was lower and showed less affinity for DHT (Km = 23.5 microM, Vmax = 0.84 nmol/min/mg protein, UDPGT velocity = 0.05 pmol/min/mg protein). No sex or age differences in 3 alpha DIOL-UDPGT activity were found in liver microsomes. The kinetic parameters and levels of androgen UDPGT activity in the skin and prostate samples were not determined because the levels of UDPGT activity were below the detection limit for our assay (0.003 pmol/min/mg protein). These results have important clinical implications. First, androgen UDPGT activity in the skin and prostate is much lower than the activity in the liver, suggesting that these tissues are not important sites for conjugation of androgens. Second, androgen UDPGT activity in the liver was not altered by sex or age in the 10 samples measured from men and women.

Adult↗