The gravity field and interior structure of Enceladus.

The small and active Saturnian moon Enceladus is one of the primary targets of the Cassini mission. We determined the quadrupole gravity field of Enceladus and its hemispherical asymmetry using Doppler data from three spacecraft flybys. Our results indicate the presence of a negative mass anomaly in the south-polar region, largely compensated by a positive subsurface anomaly compatible with the presence of a regional subsurface sea at depths of 30 to 40 kilometers and extending up to south latitudes of about 50°. The estimated values for the largest quadrupole harmonic coefficients (10(6)J2 = 5435.2 ± 34.9, 10(6)C22 = 1549.8 ± 15.6, 1σ) and their ratio (J2/C22 = 3.51 ± 0.05) indicate that the body deviates mildly from hydrostatic equilibrium. The moment of inertia is around 0.335MR(2), where M is the mass and R is the radius, suggesting a differentiated body with a low-density core.

Leptin influences histidine dipeptides and nitric oxide release from anterior pituitary cells of sheep in vitro.

Our previous results show that leptin, as well as nitric oxide (NO) and some antioxidants (histidine dipeptides - HDP) change the secretion of gonadotrophins from ovine adenohypophysis cells in vitro. NO and HDP are produced by pituitary and can modulate gonadotropin secretion by autocrine action. It is possible that these compounds mediate leptin influence on gonadotropin secretion. Therefore, the objective of the present study was to analyse leptin effect on NO and HDP (3-metyl-L-histidine, carnosine and anserine) release from ovine pituitary in vitro. Adenohypophysis cells were cultured in McCoy 5A medium with GnRH (4 x 10(-9) M) and 10(-10)-10(-5) M/l of leptin, respectively. Next, the media for analysis of NO (Griess method) and HDP (HPLC) were collected. Leptin in concentration of 10(-8)-10(-6) M/l caused a significant augmentation in NO in the culture medium, whereas in the dose of 10(-5) M/l reduced (P< or =0.05) NO release. The level of 3-metyl-L-histidine and anserine, but not carnosine, was significantly lower in the culture with 10(-8)-10(-7) M/l of leptin. Taking into account that 10(-8)-10(-7) M/l leptin stimulates LH and FSH secretion, as show in our previous study, it is possible that this effect in ewes is mediated by augmented release of NO and reduction of HDP level.

Concentrations of carnosine, anserine, L-histidine and 3-methyl histidine in boar spermatozoa and sheep milk by a modified HPLC method.

The present study deals with the application of high-performance-liquid-chromatography (HPLC) method for a quantitative detection of carnosine, anserine, L-histidine and 3-methyl-L-histidine in biological material with o-phthaldialdehyde (OPA) post column derivatisation at the constant temperature of 50 degrees C. For this purpose, some mobile-phases were prepared with scalar acetonitrile concentrations. A complete separation of all molecules, particularly for carnosine and 3-methyl-L-histidine, was obtained with a solution of acetonitrile and 6mM hydrochloric acid with 0.48 M sodium chloride (5%:95% v/v). Post column derivatisation reaction at temperature of 50'C permitted to obtain an increase in sensibility of all molecules. This method has been utilised for detection of histidine dipeptides in boar spermatozoa and in sheep milk. Concentrations (mean +/- S.E. nmol/10(9) spermatozoa) of carnosine (0.96 +/- 0.14) and anserine (0.83 +/- 0.18) in boar spermatozoa were significantly lower than those of L-histidine (52.85 +/- 4.86) and 3-methyl-L-histidine (83.07 +/- 7.1). Positive correlation was found between carnosine and anserine contents (r = 0.740; p < 0.01) and between L-histidine and 3-methyl-L-histidine (r = 0.657; p < 0.01). All histidine dipeptides studied were also present in 40 samples of sheep milk. In a case of samples without unit-forming colonies (UFC) of Staphylococcus coagulase-positive, carnosine concentrations (9.17 +/- 0.89 nmol/ml) were higher than anserine (0.51 +/- 0.02 nmol/ml) and both were significantly lower in respect to L-histidine (49.51 +/- 6.48 nmol/ml) and 3-metyl-L-histidine (81.21 +/- 6.82 nmol/ml). A negative correlation was observed between carnosine milk levels (r = -0.773; p < 0.01) and UFC/ml of Staphylococcus coagulase-positive. In conclusion this very simple and fast method can be used to detect histidine dipeptides in biological compartments where their concentrations are very low.

Influence of training on plasma adrenaline and noradrenaline kinetics in untrained standardbreds.

REASONS FOR PERFORMING STUDY: Catecholamines (CAT) play an important role in modulating the response to exercise. But the kinetics of CAT changes during exercise are difficult to study due to their short biological half-life. OBJECTIVES: Learning about variations in plasma CAT levels during training could furnish new information regarding sweating, redistribution of blood flow and energy metabolism. METHODS: Four untrained Standardbreds, adapted to treadmill work, were used to determine the influence of training on plasma adrenaline (A) and noradrenaline (NA) kinetics. Horses underwent a standardised exercise test (SET) on treadmill before (SET1), and 1 (SET2) and 2 months after (SET3) the start of a moderate training period on treadmill. The SET procedure was: warm-up and a single step of 2 min at 200 beats/min heart rate (SS). The automatic blood collection system (that has been carried out during SS) and the preparation of the horses have been described previously. The system was programmed to obtain a blood sample every 15 sec (8 blood samples per SS). Analyses were performed by HPLC. Training progress was monitored by means of anaerobic threshold velocity (V4) and the velocity during SS (V200). Wilcoxon's test was used for statistical analysis. RESULTS: Decreased levels of A and NA with significant differences between SET1/SET2 and SET1/SET3 for A (P = 0.007) and NA (P = 0.007) were found. There were no differences between SET2 and SET3 for A (P = 0.195) and NA (P = 0.054). CONCLUSIONS: Training appears to influence the level of plasma CAT and this influence is greater during the first training period in untrained Standardbreds. POTENTIAL RELEVANCE: It may prove interesting to associate the study of training-induced modifications of the concentration of plasma CAT with thermoregulation, which is under catecholaminergic control and undergoes important adaptations during training.

[Mechanical microanastomosis in reconstructive surgery of the neck and face]. / Le microanastomosi meccaniche in chirurgia ricostruttiva del distretto cervico-facciale.

Aim of the study is to report our preliminar experience with MCA Coupler System in mechanical microanastomoses performed in head and neck reconstructive surgery. During almost 7 months we performed 7 end-to-end venous anastomoses: 3 of them regarding the cephalic district. We had no vascular thrombosis, vascular congestion or flap loss. Mean time of execution of anastomosis with MCA Coupler System was 10 minutes. In our experence it is essential the choice of the appropriate size of the device and a good dissection of recipient vessels. In our opinion the Coupler System is an easy applicable device, and an efficient alternative to manual micro-anastomoses.

Coenzyme Q10 levels in pigeon (Columba livia) spermatozoa.

AIM: To assess the CoQ10 levels in pigeon spermatozoa and to verify their possible correlation with spermatic kinetic parameters. METHODS: In pigeons the sperm motility percentage (MOT%), mean linear velocity (VCM) and morphology were determined in ejaculated semen. In addition intracellular CoQ10 concentrations were also detected with a HPLC method. RESULTS: Intracellular CoQ10 levels demonstrated wide individual variations, averaging 4.85 +/- 2.31 (SD) ng/106 spermatozoa. Statistical analysis showed a positive correlation of the substance with the sperm concentration (r= 0.63; P<0.05) and with the VCM (r=0.66; P<0.05), and a negative correlation with the MOT% (r = -0.78; P=0.01). No correlation was found between the CoQ10 concentration and the percentage of normal spermatozoa. CONCLUSION: Our results suggest a possible role for CoQ10 as a "fertility marker" in pigeons, which may be employed to monitor the pharmacological effects of cytostatic substances often used to reduce the pigeon fertility in urban environment.

Papillary thyroid carcinoma metastatic to the parapharyngeal space.

Nodal metastases from head and neck primary cancer presenting as a parapharyngeal space mass are rare. This paper reports two cases of papillary thyroid carcinoma metastatic to the parapharyngeal space. This finding can be related to Rouviere's description of a direct lymphatic pathway from the posterior surface of the superior thyroid lobe to the lateral retropharyngeal nodes. Metastatic thyroid cancer should be considered in the differential diagnosis of a parapharyngeal space mass.

Assessment of trans, trans-muconic acid in human seminal plasma.

Trans, trans-muconic acid (tt-MA) is one of the most important metabolites of benzene, a pollutant ubiquitously distributed in ambient air and classified in 1982 as a group I carcinogen. For its sensitivity and specificity, tt-MA excreted in urine is considered a good biological marker of benzene exposure. In this study, seminal tt-MA levels in occupationally nonexposed subjects (n = 32) have been determined. The seminal fluid of normozoospermic subjects contained an average tt-MA concentration (170 +/- 100 ng ml-1) significantly lower than that of teratozoospermic (310 +/- 180 ng ml-1; P < 0.01), oligozoospermic (400 +/- 180 ng ml-1; P < 0.001), and oligoasthenozoospermic (430 +/- 230 ng ml-1; P < 0.01) subjects. A negative correlation existed between tt-MA levels and sperm concentration (r = - 0.62; P < 0.001), percentage of normal spermatozoa (r = - 0.41; P < 0.05), and percentage of vital spermatozoa (r = - 0.89; P < 0.001). Average tt-MA levels detected in seminal plasma were higher in smokers (350 +/- 160 ng ml-1) than in nonsmokers (280 +/- 210 ng ml-1). These results show that seminal plasma tt-MA content could be an important biological indicator for evaluating the negative effects of benzene on spermatogenesis.

Serum cytokeratins determination in differentiated thyroid carcinoma.

To assess the potential value of cytokeratins (CK) 8,18,19 as tumor markers for thyroid diseases, a study was performed comparing serum CK 8,18,19 levels in patients affected from thyroid carcinoma, adenoma, other benign thyroid diseases and healthy volunteers as controls. One hundred cases (65 patients and 35 controls) were examined. Thirty patients had thyroid carcinoma (18 papillary--PTC, 8 follicular--FTC, 4 medullary--MTC), 19 non-toxic goiter, 10 thyroid adenoma, 6 chronic thyroiditis and 35 healthy volunteers as controls. These controls were matched by age and sex. The mean value of CK in benign thyroid diseases (46.1 U/L) was significantly higher (p<0.02) than that in healthy controls (29.6 U/L). The mean value of CK in carcinomas (68.1 U/L) was significantly higher than that in healthy controls (p<0.01) and benign thyroid diseases patients (p<0.05). The positive rate of CK in thyroid carcinomas was 28.1%, while in benign thyroid diseases was 17.8%. The CK sensitivity for thyroid carcinomas was 28.1%, with a specificity of 80% and accuracy of 70.4%. In PTC patients the mean CK value was not significantly higher than in the benign diseases' group and in healthy subjects. No evident correlation between CK levels and tumor mass was found. In FTC patients the mean value was significantly higher than in the benign diseases' group and in healthy subjects. Large tumors showed the highest levels, while small tumor values were similar to the control ones. In MTC patients the mean value was significantly higher than in the benign diseases' group and in healthy subjects, with the highest peaks in large tumors and metastatic tumors. The detection of increased values in thyroid carcinomas with high metastatic potential (FTC and MTC) seems to confirm the role of these antigens in predicting the malignancy's degree of the neoplasm. These findings, if confirmed in larger series, could play an important role in assessing the CK 8,18,19 serum level as a real prognostic factor. Further repeated serum determinations after total thyroidectomy might indicate the role of CK 8,18,19 as serum markers predicting the risk of metastases.