The relationship between an athlete's maximal aerobic speed determined in a laboratory and their final speed reached during a field test (UNCa Test).

AIM: The main purpose of this study was to apply a field test to predict the maximal aerobic speed (MAS) of an athlete using the same protocol done in a laboratory. METHODS: Fourteen male subjects volunteered to participate in this study and were evaluated on four separate occasions. First, an anthropometric evaluation was carried out. Secondly, an aerobic test was done on the treadmill with a gass analyzer to measure the maximum oxygen consumption (VO2máx) and to calculate the MAS. Third, Unca test was evaluated again to confirm the reliability of the test. Finally, the participants were evaluated on field using the National University of Catamarca test (UNCa test). RESULTS: The MAS reached on a treadmill 15.6±1.0 km·h-1 was significantly higher than that found during the field test 13,6 ± 1,1 km·h-1 (P=0.0001). However the relationship between the treadmill and the field test were highly correlated in all variables: speed: r=0.83, distance covered r= 0,81, test duration r=0.83. CONCLUSION: If MAS found on a treadmill is considered to be "the gold-standard" to validate MAS on field, it can be said that the UNCa test underestimates speed.

Effects of 17 beta-estradiol and trimegestone alone, and in combination, on the bone and uterus of ovariectomized rats.

Trimegestone is a novel norpregnane progestin, which is being developed, in combination with 17 beta-estradiol, for the treatment of menopausal symptoms and prevention of postmenopausal osteoporosis. A model of osteoporosis in the ovariectomized rat has been used to evaluate the effects of 17 beta-estradiol and trimegestone, alone and in combination, on bone and uterus in these animals. Two treatment protocols were investigated, preventive with treatment starting immediately after ovariectomy and curative with treatment starting 1 or 6 months after ovariectomy. 17 beta-Estradiol was administered subcutaneously at a dose of 10 micrograms/kg/day with trimegestone or norethisterone being administered orally at a dose of 1 mg/kg/day; treatment was given 5 days per week. Treatment on both protocols was for 6 months. Given alone, 17 beta-estradiol maintained bone mass, either partially or completely, when given on the preventive protocol, or on the curative protocol with treatment starting 1 month after ovariectomy; it did not restore bone mass when given on the curative protocol with 6 months lapsing between ovariectomy and start of treatment. Trimegestone did not block the beneficial effects of 17 beta-estradiol on bone. 17 beta-Estradiol induced uterine hypertrophy on all these protocols and this was blocked completely by trimegestone. Trimegestone administered alone had no effect on bone or uterus but, when given in combination with 17 beta-estradiol, it did not inhibit the effect of 17 beta-estradiol in maintaining bone mass but completely blocked its uterotropic effect. Norethisterone at a similar dose did not inhibit the effects of 17 beta-estradiol on bone but also did not block its uterotropic effect.

Role of endoproteolytic processing in the adhesive and signaling functions of alphavbeta5 integrin.

Some integrin alpha subunits undergo a post-translational cleavage in their extracellular domain. However, the role of this cleavage in integrin function is unclear. Enzymes involved in this maturation belong to the subtilisin-like endoprotease family (convertases). To understand the role of the alpha subunit cleavage in integrin function, we have designed stable transfectants (PDX39P cells) expressing alpha(1)-PDX, a convertase inhibitor. Immunoprecipitation of cell surface proteins from PDX39P showed that alpha(3), alpha(6) and alpha(v) integrins lack endoproteolytic cleavage. We have compared adhesion between PDX39P cells and mock-transfected cells on different extracellular matrix proteins. No difference in adhesion could be observed on laminin-1 and type I collagen, while attachment of PDX39P cells to vitronectin (ligand of the alpha(v)beta(5) integrin) was dramatically reduced. The reduced adhesion of PDX39P cells was not due to changes in integrin affinity as determined by solid-phase receptor assay in a cell-free environment. Intracellular signaling pathways activated by alpha(v) integrin ligation were also affected in PDX39P cells. It thus seems that the absence of endoproteolytic cleavage of alpha(v) integrins has important consequences on signal transduction pathways leading to alterations in integrin function such as cell adhesion.

Serum factors inhibit melanoma cell surface expression of type I and type II IGF receptors.

We have identified one class of IGF-I-binding sites and two classes of IGF-II-binding sites at the surface of the melanoma cell line IGR39. By means of affinity labeling with 125I-IGF-I, 290-300 kDa form was characterized. Using 125I-IGF-II, a 270 kDa polypeptide was labeled, corresponding to the type II IGF receptor. In the two serials of experiments, the order of potency in inhibiting 125I-IGF-I or 125I-IGF-II labeling of IGF-related peptides and alpha IR3, an antibody directed against type I receptor alpha subunit, was the same as in competition experiments. When IGR39 cells were cultured in a serum-free medium, the number of both high affinity IGF-II and IGF-I binding sites was increased, by 8- and 5-fold respectively, without any significant change in Kd values. In both culture conditions, we found IGFBP-2, -3 -4 and a 30 kDa form which Mr was consistent with IGFBP-5 or -6. Except for IGFBP-2, the amount of secreted IGFBPs was modified depending on culture conditions: in conditioned medium from cells cultured with 10% FCS, the amount of IGFBP-3 or -4 was higher, and the amount of the 30 kDa IGFBP was lower when compared to conditioned medium from cells cultured in serum-free medium.

Formation of bile canaliculi in long-term primary cultures of adult rat hepatocytes on permeable membrane: an ultrastructural study.

Adult rat hepatocytes were cultured for 15 days on type I collagen-coated permeable membranes in a hormonally defined Waxman's modified medium supplemented with very low concentrations of insulin, glucagon and dexamethasone. Phase contrast examination showed that 15-day-old cultures still formed a regular monolayer of polygonal cells. In similarly aged cultures, intracellular glycogen was abundant and evenly distributed, while steatosis remained very limited. Scanning and transmission electron microscopy showed that well developed bile canaliculi could be observed on the lateral side of the hepatocyte membrane after 4 days of incubation and persisted for 2 weeks. These canalicular structures probably originated from coalescence of membrane invaginations observed in 1-day-old cultures. Transmission electron microscopy showed that the ultrastructure of the cells was very close to that of normal rat hepatocytes in the intact liver. These results suggest that rat hepatocytes cultured under these experimental conditions are able to develop and maintain tissue-specific cytochemical and morphological properties for at least 15 days.

Effects of 4 weeks of treatment with trandolapril on renal hypertension and cardiac and vascular hypertrophy in the rat.

The effects of the angiotensin-converting enzyme inhibitor trandolapril were studied using a Goldblatt (two-kidney, one-clip) rat model of renovascular hypertension after 4 weeks of oral treatment at 0.3 or 1 mg/kg/day. The effects of trandolapril on blood pressure and on cardiac and vascular hypertrophy were analyzed in comparison with the control group. Trandolapril produced a rapid, dose-dependent decrease in blood pressure, which plateaued after 2 weeks of treatment. Complete normalization of blood pressure was observed at a daily dose of 1 mg/kg. Dose-dependent inhibition of cardiac hypertrophy was also observed, heart:body weight ratio being decreased by 17 and 30% at 0.3 and 1 mg/kg, respectively, leading to a normalization of this parameter at the higher dose compared with normotensive controls. Similarly, trandolapril produced a marked decrease in vascular wall hypertrophy in both the mesenteric artery and the aorta. Indeed, complete normalization of media thickness was observed, compared with the normotensive control group, at 1 mg/kg of trandolapril. These results show that short-term treatment with trandolapril can induce complete regression of cardiac and vascular hypertrophy, which is associated with the development of renal hypertension.

Effects of subchronic treatment with trandolapril and enalapril on cardiovascular morphologic alterations in the aged spontaneously hypertensive rat with heart failure.

The effects of a 3-month treatment period with the angiotensin-converting enzyme (ACE) inhibitors trandolapril (0.3 mg/kg/day, p.o.) and enalapril (10 mg/kg/day, p.o.) on hemodynamics, cardiac hypertrophy, and vascular structures were examined in old spontaneously hypertensive rats (SHRs) (24 months at the end of treatment) presenting with congestive heart failure. During the course of treatment, the mortality rate was lower in the two treated groups than in the control group. At the end of treatment, serum ACE activity was inhibited by 63 and 33% by trandolapril and enalapril, respectively, but the decrease in blood pressure they induced was not significant. The atrial natriuretic factor(ANF) plasma levels and cyclic GMP urine excretion were about 10-fold and 3-fold higher, respectively, in old SHRs than in old Wistar rats. These values were markedly decreased by both ACE inhibitors. The ventricular hypertrophy was greatly decreased by both compounds (-24% by trandolapril and -26% by enalapril). In the aorta, the media hypertrophy was significantly decreased and nuclear density increased to a similar extent by both ACE inhibitors. In the mesenteric artery, trandolapril treatment induced a complete regression of the media hypertrophy and a marked decrease in extracellular matrix surface. In addition, the collagen network appeared less dissociated in the treated animals. Similarly the nuclear density was increased and the surface of cell nuclei was decreased by trandolapril. Enalapril appeared much less potent on these parameters. These data demonstrate that treatment with trandolapril of aged SHRs presenting with heart failure results in an increase in survival of the animals and a marked regression of cardiac and vascular hypertrophy.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of trandolapril on vascular morphology and function during the established phase of systemic hypertension in the spontaneously hypertensive rat.

The aim of this study was to determine the morphologic and functional vascular changes occurring following 4 weeks of treatment with the angiotensin-converting enzyme inhibitor trandolapril in the spontaneously hypertensive rat (SHR) in the established phase of hypertension. At the dosage used, 0.4 mg/kg orally, trandolapril decreased blood pressure of the SHR by 15-18% compared with that of the control animals. Immediately before the end of treatment, the following changes from control values were observed: (1) 9, 11, and 12% reductions for myocardial hypertrophy and the media thickness of the thoracic aorta and femoral arteries, respectively; and (2) an increase in the compliance of the resistance arteries, demonstrated by a shift to the right of the in vitro tension-diameter curves and a significant 22% increase in their normalized internal diameter, while their maximum contractile ability was significantly decreased. Following discontinuation of treatment, blood pressure levels remained significantly lower in the treated versus the control groups for up to 4 weeks after the last administration. At that time measurement of the studied parameters showed: (1) a rapid reversion to control values of the compliance of the resistance vessels; and (2) a slower progression, but in the same direction, in the parameters of cardiac and vascular hypertrophy. Thus, trandolapril, administered for a short period in the adult SHR, was able to reverse the cardiac and vascular morphologic changes present in this model of hypertension. Like the effect on blood pressure, these effects were slowly reversible at the end of treatment, whereas the functional consequences at the resistance artery level seemed to display a more rapid reversibility.

Modulation of the expression of the VIP receptor by serum factors on the human melanoma cell line IGR39.

IGR39 cells, isolated from a human superficial melanoma, display at their surface high and low affinity receptors for the vasoactive intestinal peptide (VIP). When grown in DME medium supplemented with 10% fetal calf serum, cells display 1.6 x 10(5) high affinity (Kd 0.74 nM) and 5.6 x 10(5) low affinity (Kd 55 nM) VIP binding sites per cell. When cultured in a chemically defined medium containing EGF, transferrin, and selenium, IGR39 cells display many neurite-like extensions. Following these morphological changes, the specific [125I]VIP binding is increased four- to fivefold after 6 days in culture. This phenomenon is reversible and is the result of an increased number of VIP binding sites available at the cell surface, without modification of their affinities. The molecular mass of the binding sites is also unchanged whatever cell culture conditions. Increase in [125I]VIP binding is inversely correlated to the serum concentration in the culture medium. When added to the chemically defined medium, sera from various origins as well as some serum substitutes reduce [125I]VIP binding to the same extent as that of the serum. The total cAMP production by VIP-stimulated IGR39 cells is enhanced by a factor of six to seven when cells are cultured in serum-free medium, in good correlation with the increase of VIP binding capacity. These data suggest that factor(s) present in fetal calf serum inhibit(s) the expression of VIP receptor, thus demonstrating the importance of a strict control of cell culture conditions for in vitro studies.

Solubilization of the active vasoactive intestinal peptide receptor from human colonic adenocarcinoma cells.

The non-ionic detergent n-octyl-beta-D-glucopyranoside was used to solubilize the VIP (vasoactive intestinal peptide) receptor from human colonic adenocarcinoma cell line HT29-D4. The binding of monoiodinated 125I-VIP to the solubilized receptor was specific, time-dependent, and reversible. Scatchard analysis of data obtained from competitive displacement of monoiodinated 125I-VIP by native VIP suggested the presence of two classes of VIP binding sites with Kd values of 0.32 and 46.7 nM. The binding capacities of these two classes were 1.7 x 10(10) and 30.2 x 10(10) sites/mg of proteins, respectively. The solubilized receptor retained the specificity of the human VIP receptor towards the peptides of the VIP/secretin/glucagon family. The order of potency in inhibiting monoiodinated 125I-VIP binding was VIP (IC50 = 1.0 x 10(-9) M) much greater than peptide histidine methionine amide (IC50 = 10(-7) M) greater than growth hormone-releasing factor (IC50 = 3 x 10(-7) M) greater than secretin (IC50 greater than 10(-6) M); glucagon had no effect on VIP binding. The reducing agent dithiothreitol inhibited in a dose-dependent manner the binding of 125I-VIP. Covalent cross-linking experiments between the solubilized receptor and 125I-VIP showed that after sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography two major and one minor polypeptides of Mr 67,000, 72,000, and 83,000 were specifically labeled. When analyzed by gel filtration, the n-octyl-beta-D-glucopyranoside-solubilized 125I-VIP-receptor complex was resolved into two major peaks with molecular mass in the range of 60-70 and 270-300 kDa. Thus, the soluble form of the VIP receptor was probably a multimeric complex in which disulfide bonds may play an important role to hold the receptor in an active configuration.

Effect of in vivo injection of recombinant human interleukin-2 on peritoneal macrophages from MRL-lpr/lpr mice.

Different characteristics of peritoneal macrophages have been studied, to assess the role of macrophages in the pathogenesis of MRL-lpr/lpr mice which develop a lupus-like syndrome. Resident peritoneal macrophages from MRL-lpr/lpr mice (greater than 10 weeks old) displayed characteristics of activation, while thioglycollate-elicited or resident macrophages from normal mice (Balb/c or MRL-+/+) did not. In addition to Ia antigens, macrophages spontaneously expressed Interleukin-2 receptors (IL2-R) whereas resident macrophages from normal mice did not. Injection of recombinant human Interleukin-2 (rHu-IL2) by the i.p. route to normal mice did not modify the cellular composition of the resident peritoneal population. On the contrary, rHu-IL2 treatment of MRL-lpr/lpr mice induced an enhancement in cell number in the peritoneal cavity. At the same time, macrophages harvested from treated MRL-lpr/lpr mice showed enhanced chemiluminescence triggered by phorbol-12-myristate-13-acetate (PMA) whereas peritoneal macrophages from treated normal mice did not. These results indicate that MRL-lpr/lpr peritoneal macrophages display features of selective 'activation' and suggest that the expression of IL2-R could be involved in the pathogenesis of inflammatory disorders seen in MRL-lpr/lpr autoimmunity.

Early glycogenesis in the uterine glandular cells of the rabbit induced by progestins: a quantitative investigation.

A single administration of progesterone (P) to primed immature rabbits induces the appearance of glycogen in uterine glandular cells. This phenomenon, which is rapid and transitory, precedes a mitotic surge in the glandular epithelium. Ultrastructural studies allowed us to observe the beginning of glycogenesis as early as 1 h after the injection of P. Quantitative image analysis in the course of a kinetic study showed that glycogen levels reached a maximum at the sixth h and after 24 h had fallen dramatically. Promegestone, a potent progestomimetic compound, gave similar results, but estradiol, testosterone and dexamethasone failed to induce the appearance of glycogen in the uterine glands. Mifepristone (RU 486) had an antagonistic effect on the action of P. These results suggest that early P-dependent glycogenesis in the endometrial glandular cells of the rabbit may play an important role in the increased rate of mitosis and cellular proliferation that are necessary events in preparing the endometrium for implantation.

Effect of a new topically active antiandrogen (RU 38882) on the rat sebaceous gland: comparison with cyproterone acetate.

RU 38882 is a new antiandrogen. When given by subcutaneous or oral route, RU 38882 is about 25 times less potent than cyproterone acetate. However, when applied topically to the intact rat skin, RU 38882 (0.25-25 mg/rat/day for 5 days or 3 weeks) decreases, in a dose-related manner, the volume density of the smooth endoplasmic reticulum vesicles of the differentiating cells of the sebaceous gland, a structure directly involved in sebum lipid synthesis. Under these conditions RU 38882 is about 100 times more potent than cyproterone acetate and unlike cyproterone acetate, does not modify the prostate weight. The lack of efficacy of cyproterone acetate on the sebaceous gland could be due to its partial androgenic activity while RU 38882, under these conditions, acts as a pure antiandrogen which inhibits the nuclear androgen-receptor translocation.

Ultrastructural changes in the uropygial gland of the male Japanese quail, Coturnix coturnix, after testosterone treatment. Comparison with the sebaceous gland of the male rat.

The ultrastructure of the uropygial gland of the male quail was compared to that of the sebaceous gland of the male rat after castration and testosterone treatment of both species. In intact animals, the differentiating cells of these glands displayed almost the same pattern as regards their smooth endoplasmic reticulum, an organelle involved in lipogenesis in both cases. Castration reduced the volume of this organelle, while testosterone administration restored cell morphology to a normal or supranormal level. Finally, this study showed that at ultrastructural level, there is a close functional analogy between the uropygial gland of quail and the sebaceous glands of rats as regards their androgen dependency. Consequently, the uropygial gland might be an attractive model for study of action of androgens on sebaceous-like glands.

Extracellular material secreted by human colonic adenocarcinoma cell lines promotes spreading in serum-free medium and induces neurite outgrowth of PC-12 cells.

A completely defined medium has been designed to promote cell proliferation of 2 colonic adenocarcinoma cell lines of epithelial origin (HT 29 and HRT 18). The spreading of both cell types, especially of HT 29 cells, was not possible in a serum-free medium supplemented with growth factors. Spreading was obtained in a defined medium (a 1/1 mixture of DMEM and F12 media supplemented with 5 micrograms/ml transferrin, 5 ng/ml EGF, 10 ng/ml selenite and 15 mM HEPES pH 7.3) with an extracellular matrix-like material (ECM) secreted by the cells themselves. The properties of the ECM have been studied: ECM secreted by the 2 cell lines induced very quick spreading of HT 29 and HRT 18 cells (1 to 2 hr vs. 12 to 24 hr in serum-supplemented medium). ECM induced morphological differentiation of a rat pheochromocytoma cell line (PC 12). PC-12 cells grown under these conditions began to develop neurite extensions as early as 2 hr after seeding.

The role of intracellular lumina in the repolarization process of a colonic adenocarcinoma cell line.

When glucose is added to the culture medium, some cells of the undifferentiated HT-29 line derived from a human colonic adenocarcinoma develop spherical structures, demonstrated to be intracellular by the ruthenium red staining method, which are bordered with microvilli, contain osmiophilic substances and resemble intracellular lumina. When glucose is replaced by galactose in the culture medium, the cells differentiate apical membranes bordered with microvilli. Our observations suggest that these new apical membranes correspond to the membranes of intracellular lumina which have opened outside the cells. We suggest that intracellular lumina may represent "compensation" for loss of polarity of epithelial cells and may be an important step in the repolarizing process of the cells.

Effects of progestins and antiprogestins on mitochondria in uterine glandular cells in the rat. A quantitative investigation.

The administration of progesterone to ovariectomized rats induces an increase in the volume density (Vv) of the mitochondria and the appearance of giant mitochondria in the uterine glandular cells. This experimental model, including a stereological analysis, allowed us to investigate and quantify a direct effect of progesterone on a well-defined cellular structure without the intervention of estrogen in a priming phase. Synthetic compounds, promegestone, gestrinone and RU 38486, were tested in this model either in place of progesterone or simultaneously with progesterone. The potent progestomimetic activity of promegestone was confirmed by the proliferation of giant mitochondria and a high Vv value for the mitochondria, the two other compounds being inactive even at higher doses. At lower doses, gestrinone and RU 38486 partially inhibit the action of progesterone and at higher doses they both show a complete antagonist effect by preventing the development of the mitochondria.

Ultrastructural changes of sebaceous glands in castrated and testosterone-treated male rats. A qualitative and quantitative study.

The effect of testosterone on the sebaceous gland was studied in the male rat. Biopsies of dorsal skin from intact rats, from rats four weeks after castration, and from castrated rats treated with testosterone propionate for three weeks at a dose of 250 micrograms/kd/day (s.c.) were examined by electron microscopy. In the treated animals intermediate sacrifices were performed on days 4, 7, 14, 21. Stereology was used for a morphometric analysis of the smooth endoplasmic reticulum (SER). The presence of a vesicular endoplasmic reticulum throughout the cytoplasm of differentiating cells was observed in the sebaceous glands of intact rats. Following castration there was a shrinkage of these cells and a striking decrease in the volume density of the endoplasmic reticulum vesicles. The administration of testosterone to gonadectomized rats resulted in an increase in vesicle content above the normal level from the first week as revealed by stereological analysis. This study confirms the trophic effect of the androgen on the sebaceous gland at a subcellular level. Furthermore, it is shown that stereology is a useful method for detecting early hormone-induced changes and could be valuable for studying the effects of anti-androgens on this gland.