Variability at different spatial scales of a coralligenous assemblage at Giannutri Island (Tuscan Archipelago,northwest Mediterranean)

This study was carried out on the rocky cliffs of Giannutri Island (Tyrrhenian Sea, Italy) to test the hypothesis that coralligenous assemblages are consistent within the bathymetric range considered (25–35 m depth) over three different spatial scales (1000 m, 100 m and 10 m). A multi-factorial sampling design was used to assess patterns of vertical distribution in the studied area. Data on the percent cover of algae and invertebrates were collected at three depths (25, 30 and 35 m) using a photographic method, and percentage cover was obtained using a visual method. Analysis of the results using ANOVA indicated that the distribution and abundance of algae and some invertebrates of the sublittoral assemblages are clearly heterogeneous. Algae, sponges and bryozoans showed significant variability in distribution and abundance at different depths, but this variability was not consistent amongst transects. Ascidians did not show any variability, while the abundance of anthozoans differed significantly amongst transects. We concluded that heterogeneity in the distribution and abundance of the taxa analysed is related to the smallest spatial scale investigated (10's of m). Some of the possible causes of the observed variability are discussed.     

A new luminescence immunoassay for thyrotropin using coated tubes: Evaluation and comparison with immunoradiometric assay

A recently available chemiluminescence immunoassay (LIA-MAT) for TSH, set up by Byk-Sangtec Diagnostica, has been evaluated and compared with IRMA methods. The system LIA-MAT uses two monoclonal antibodies: one coated on tubes and the other labelled with isoluminol. To compute the within-assay precision profile, we estimated the response error relationship from all the duplicates (420) of eleven experiments. The CV of the response was 4–5% from the maximal response until 10,000 RLU (corresponding to about 1 μlU/ml); in the lower response range the CV worsened up to 8%. The sensitivity, derived from the precision profile, was 0.052 μlU/ml similar to that found in IRMA-MAT (0.044 μlU/ml); the working range extended from 0.33 to 100 μlU/ml. Results from LIA-MAT in the concentration range 1–30 μlU/ml were compared with the consensus mean produced by users of IRMA methods (IRMA-MAT, IRMA-Behring, Maiaclone Serono) participating in an inter-laboratory survey; a good correlation with IRMA techniques was found. The distribution of TSH determinations produced by LIA-MAT on 62 low concentration sample (<0.3 μlU/ml) from patients unresponsive to TRH test, was found similar to that observed for the kit IRMA Boots-Celltech assumed as reference.     

Formation of micronuclei and of clastogenic factor(s) in patients receiving therapeutic doses of iodine-131

The micronucleus (MN) assay in peripheral blood lymphocytes was applied to assess the genotoxic potential of a single dose of iodine-131 (131I) given to six patients for ablation of thyroid remnants after total thyroidectomy. Lymphocytes were taken at various times after 131I therapy (from 2 to 180 days), and evaluated for the presence of MN in the binucleated cells identified after blocking cytokynesis with cytochalasin B. The presence of ultrafiltered, low-molecular weight, clastogenic factor(s) (CFs) in the plasma of 11 patient undergoing 131I therapy was also sequentially assessed.A significantly increased MN frequency was observed in lymphocytes of patients as soon as the first sampling time (2 days after 131I therapy), multifactor analysis of variance (MANOVA): P<0.0001, peaking at day 7 at almost four-fold the spontaneous frequency observed in the pre-therapy samples. MN frequency slowly declined thereafter, reaching the baseline levels at the 180-day time point. When tested against peripheral blood lymphocytes from a healthy donor, the ultrafiltered CFs obtained from 11 patient's plasma induced a significant increase of the MN frequency peaking at day 15. Thereafter, a slow MN frequency decline was observed and the baseline frequency was reached after 180 days. A significant relationship was found between the MN frequency observed in lymphocytes of patients after 131I therapy and the genotoxic CFs activity present in their plasma (P=0.019).These findings suggest that 131I induces a significant increase in the MN frequency of peripheral blood lymphocytes, as well as the formation of transferable CFs which persist for at least 60 days after administration of the radionuclide. The presence of these CFs might be responsible of chromosome aberrations often observed in cultured lymphocytes following X-ray exposure. The possibility of reducing the genotoxic activity of radionuclide therapy by chemoprevention of CFs with antioxidant drugs remains to be explored.     

Relevance of the single ommatidium performance in determining the oscillatory response of the Limulus retina

The response of a healthy lateral eye of Limulus to constant, uniform and sufficiently intense light stimulation, consists of a sustained oscillatory discharge, all ommatidia firing synchronously in bursts, at intervals of about 0.2 s (Barlow and Fraioli, 1978). This response has been analysed by a computer simulation, where the performance of the single unit is described by encoder models of the integrate-and-fire type, already extensively investigated. The results obtained show that the occurrence and the time features of the oscillatory response depend on the neural models adopted.     

Carbonate standing stock and carbonate production of the bryozoanPentapora fascialis in the North-Western Mediterranean

Summary Pentapora fascialis, one of the largest living bryozoan, is often a predominant part of the benthos on hard subtidal bottoms in the Mediterranean Sea. Conversion factors calculated from laboratory measurements of colony size, biomass and skeleton weight, combined with density of colonies and mean annual growth rate allowed the estimation of carbonate standing stock, biomass and carbonate production ofPentapora fascialis in five sites in the Ligurian Sea. Carbonate standing stock ranged from 281 to 2490 g·m⁻², colony biomass varied from 8.82 to 78.01 g·m⁻², with a ratio biomass to carbonate standing stock of about 3%. Carbonate production of the bryozoan ranged in the five sites from 358 to 1214 g·m⁻²·y⁻¹. If compared with the few data available on carbonate production of bryozoans and other sublittoral benthic bioconstructors in the temperate regions,Pentapora fascialis has to be considered one of the major contributors to the carbonatebudget.     

Analytical and clinical assessment of a commercial kit for the simultaneous determination of free thyroxine and thyrotropin

The SimulTRAC FT4/TSH kit (Becton Dickinson), allowing a simultaneous determination of free thyroxine (FT4) and thyrotropin (TSH), was assessed in terms of analytical quality and clinical performance. The results of a multicenter trial were included in this study to obtain a more complete and reliable information. The current validation procedures (ie evaluation of analytical imprecision and sensitivity, between-kit comparison of estimates and--limited to TSH--check of response linearity on dilution) demonstrated quite acceptable analytical characteristics for both the FT4 and the TSH tests. The diagnostic sensitivity and predictive value were derived for separate and combined tests from a relatively large number of cases (ie 401 euthyroids, 127 overt and 48 subclinical hypothyroids, 205 overt and 80 compensated hyperthyroids). The TSH test proved more effective than FT4 in discriminating both overt and subclinical dysfunctions, and, in this respect, the test association was found to add a little advantage--if any. However, the extension of the concepts of diagnostic efficiency to any combination of test results--favoured by their production in a single assay--provides a basis to establish diagnostic protocols and to predict costs and benefits of medical actions.     

Radioimmunoassay of unconjugated and total serum estetrol using a 125I-iodinated tracer

A radioimmunossay (RIA) for the measurement of both unconjugated and total serum estetrol has been developed, using an antiserum to an E4-3-conjugate and a 125I-radioiodinated E4 tracer. Assay of dried ethyl ether extracts was used for the determination of unconjugated E4, while a direct measurement of unextracted hydrolyzed serum in the presence of 0.3% 8-anilino-1-naphthalene sulphonic acid (ANS) proved adequate for total E4. Assay reliability was evaluated and the procedure standardized through a series of tests aimed at assessing accuracy, sensitivity and precision. No steroidal interference was found to practically affect the assay (0.3% estriol cross-reactivity), nor were solvent and sample blanks observed in the case of unconjugated E4. For total E4 assay, the sample blank effects were acceptably overcome by using hydrolyzed male serum and 0.3% ANS, as a standard diluent. An interassay variability amounting to approximately 10 and 6% resulted for unconjugated E4 and total E4 RIA, respectively. A number of serum samples (285 for unconjugated E4, 147 for total E4) randomly collected throughout normal pregnancy were assayed. The unconjugated E4 levels at 15th week and at term were 62.7 +/- 22.6 and 766.5 +/- 208.2 (SD) pg/ml, respectively. Total E4 was about 6--7 times higher than the levels of free E4 and increased 7 times from the 15th week to term.     

CA 195: a new monoclonal antibody-defined Lea blood group-related tumor marker in patients with epithelial ovarian cancer.

The levels of CA 125 (reference values [RV]s = 35 U/mL and 65 U/mL), CA 19.9 (RV = 40 U/mL), CA 50 (RV = 20 U/mL) and CA 195 (RVs = 10.5 U/mL and 15 U/mL) were measured in blood samples collected before laparotomy from 71 patients with ovarian carcinoma and 204 patients with benign ovarian pathology as controls. CA 125 levels greater than 35 U/mL were observed in 53/61 patients with non-mucinous carcinomas and in 6/10 with mucinous ones, while antigen levels above 65 U/mL were detected in 50/61 patients with non-mucinous malignancies and in 6/10 with mucinous ones; therefore mucinous tumors expressed this antigen less frequently than non-mucinous ones. Elevated CA 19.9 levels were found in 15/61 patients with non-mucinous malignancies and in 8/10 with mucinous ones. Raised CA 50 levels were observed in 13/50 patients with non-mucinous cancers and in 7/8 with mucinous ones. CA 195 values were greater than 10.5 U/mL and 15 U/mL respectively in 20.0% and in 15.0% of 40 patients with non-mucinous tumors, while antigen levels were above 10.5 U/mL and 15 U/mL respectively in 75.0% and 62.5% of 8 patients with mucinous carcinomas. Therefore, CA 19.9, CA 50 and CA 195 highly correlated with mucinous histotype. The results of CA 195 and CA 19.9 determinations were very similar because of the closely related: structures of the two epitopes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of growth hormone-releasing hormone and clonidine on growth hormone release in type 1 diabetic patients

We administered growth-hormone releasing hormone (GHRH), clonidine or thyrotropin-releasing hormone (TRH) as intravenous boli each in three different randomized mornings to nine well-controlled Type 1 diabetic men and to six age-matched healthy men who served as controls. GHRH and clonidine evoked a prompt and brisk GH release both in diabetic and in control subjects with no significant difference being evident between the two groups. Only one diabetic subject showed a paradoxical GH release after TRH when he was under long-term poor metabolic control. These results indicate that in insulin-dependent patients with good control of the metabolic disease the response of somatotropes to pituitary- or central nervous system-directed stimuli is normal. These data are supportive of the idea that altered GH secretion in Type 1 diabetes rather than reflecting a primary hypothalamic and/or pituitary alteration may be a state-dependent phenomenon related to the metabolic state of the disease.