Bioremediation for the recovery of oil polluted marine environment, opportunities and challenges approaching the Blue Growth

The Blue Growth strategy promises a sustainable use of marine resources for the benefit of the society. However, oil pollution in the marine environment is still a serious issue for human, animal, and environmental health; in addition, it deprives citizens of the potential economic and recreational advantages in the affected areas. Bioremediation, that is the use of bio-resources for the degradation of pollutants, is one of the focal themes on which the Blue Growth aims to. A repertoire of marine-derived bio-products, biomaterials, processes, and services useful for efficient, economic, low impact, treatments for the recovery of oil-polluted areas has been demonstrated in many years of research around the world. Nonetheless, although bioremediation technology is routinely applied in soil, this is not still standardized in the marine environment and the potential market is almost underexploited. This review provides a summary of opportunities for the exploiting and addition of value to research products already validated. Moreover, the review discusses challenges that limit bioremediation in marine environment and actions that can facilitate the conveying of valuable products/processes towards the market.

Amphidinium spp. as a Source of Antimicrobial, Antifungal, and Anticancer Compounds

Dinoflagellates make up the second largest marine group of marine unicellular eukaryotes in the world ocean and comprise both heterotrophic and autotrophic species, encompassing a wide genetic and chemical diversity. They produce a plethora of secondary metabolites that can be toxic to other species and are mainly used against predators and competing species. Dinoflagellates are indeed often responsible for harmful algal bloom, where their toxic secondary metabolites can accumulate along the food chain, leading to significant damages to the ecosystem and human health. Secondary metabolites from dinoflagellates have been widely investigated for potential biomedical applications and have revealed multiple antimicrobial, antifungal, and anticancer properties. Species from the genus Amphidinium seem to be particularly interesting for the production of medically relevant compounds. The present review aims at summarising current knowledge on the diversity and the pharmaceutical properties of secondary metabolites from the genus Amphidinium. Specifically, Amphidinium spp. produce a range of polyketides possessing cytotoxic activities such as amphidinolides, caribenolides, amphidinins, and amphidinols. Potent antimicrobial properties against antibiotic-resistant bacterial strains have been observed for several amphidinins. Amphidinols revealed instead strong activities against infectious fungi such as Candida albicans and Aspergillus fumigatus. Finally, compounds such as amphidinolides, isocaribenolide-I, and chlorohydrin 2 revealed potent cytotoxic activities against different cancer cell lines. Overall, the wide variety of antimicrobial, antifungal, and anticancer properties of secondary metabolites from Amphidinium spp. make this genus a highly suitable candidate for future medical applications, spanning from cancer drugs to antimicrobial products that are alternatives to currently available antibiotic and antimycotic products.

Copper Effect on Microalgae: Toxicity and Bioremediation Strategies

Microalgae are increasingly recognised as suitable microorganisms for heavy metal (HM) removal, since they are able to adsorb them onto their cell wall and, in some cases, compartmentalise them inside organelles. However, at relatively high HM concentrations, they could also show signs of stress, such as organelle impairments and increased activities of antioxidant enzymes. The main aim of this review is to report on the mechanisms adopted by microalgae to counteract detrimental effects of high copper (Cu) concentrations, and on the microalgal potential for Cu bioremediation of aquatic environments. Studying the delicate balance between beneficial and detrimental effects of Cu on microalgae is of particular relevance as this metal is widely present in aquatic environments facing industrial discharges. This metal often induces chloroplast functioning impairment, generation of reactive oxygen species (ROS) and growth rate reduction in a dose-dependent manner. However, microalgae also possess proteins and small molecules with protective role against Cu and, in general, metal stress, which increase their resistance towards these pollutants. Our critical literature analysis reveals that microalgae can be suitable indicators of Cu pollution in aquatic environments, and could also be considered as components of eco-sustainable devices for HM bioremediation in association with other organisms.

Bioinformatic prediction of putative metallothioneins in non-ciliate protists

Intracellular ligands that bind heavy metals (HMs) and thereby minimize their detrimental effects to cellular metabolism are attracting great interest for a number of applications including bioremediation and development of HM-biosensors. Metallothioneins (MTs) are short, cysteine-rich, genetically encoded proteins involved in intracellular metal-binding and play a key role in detoxification of HMs. We searched approximately 700 genomes and transcriptomes of non-ciliate protists for novel putative MTs by similarity and structural analyses and found 21 unique proteins playing a potential role as MTs. Most putative MTs derive from heterokonts and dinoflagellates and share common features such as (i) a putative metal-binding domain in proximity of the N-terminus, (ii) two putative MT-specific domains near the C-terminus and (iii) one to three CTCGXXCXCGXXCXCXXC patterns. Although the biological function of these proteins has not been experimentally proven, knowledge of their genetic sequences adds useful information on proteins that are potentially involved in HM-binding and can contribute to the design of future biomolecular assays on HM-microbe interactions and MT-based biosensors.

Highly Valuable Polyunsaturated Fatty Acids from Microalgae: Strategies to Improve Their Yields and Their Potential Exploitation in Aquaculture

Microalgae have a great potential for the production of healthy food and feed supplements. Their ability to convert carbon into high-value compounds and to be cultured in large scale without interfering with crop cultivation makes these photosynthetic microorganisms promising for the sustainable production of lipids. In particular, microalgae represent an alternative source of polyunsaturated fatty acids (PUFAs), whose consumption is related to various health benefits for humans and animals. In recent years, several strategies to improve PUFAs' production in microalgae have been investigated. Such strategies include selecting the best performing species and strains and the optimization of culturing conditions, with special emphasis on the different cultivation systems and the effect of different abiotic factors on PUFAs' accumulation in microalgae. Moreover, developments and results obtained through the most modern genetic and metabolic engineering techniques are described, focusing on the strategies that lead to an increased lipid production or an altered PUFAs' profile. Additionally, we provide an overview of biotechnological applications of PUFAs derived from microalgae as safe and sustainable organisms, such as aquafeed and food ingredients, and of the main techniques (and their related issues) for PUFAs' extraction and purification from microalgal biomass.

Fatty Acids Derivatives From Eukaryotic Microalgae, Pathways and Potential Applications

The exploitation of petrochemical hydrocarbons is compromising ecosystem and human health and biotechnological research is increasingly focusing on sustainable materials from plants and, to a lesser extent, microalgae. Fatty acid derivatives include, among others, oxylipins, hydroxy fatty acids, diols, alkenones, and wax esters. They can occur as storage lipids or cell wall components and possess, in some cases, striking cosmeceutical, pharmaceutical, and nutraceutical properties. In addition, long chain (>20) fatty acid derivatives mostly contain highly reduced methylenic carbons and exhibit a combustion enthalpy higher than that of C_14–20 fatty acids, being potentially suitable as biofuel candidates. Finally, being the building blocks of cell wall components, some fatty acid derivatives might also be used as starters for the industrial synthesis of different polymers. Within this context, microalgae can be a promising source of fatty acid derivatives and, in contrast with terrestrial plants, do not require arable land neither clean water for their growth. Microalgal mass culturing for the extraction and the exploitation of fatty acid derivatives, along with products that are relevant in nutraceutics (e.g., polyunsaturated fatty acids), might contribute in increasing the viability of microalgal biotechnologies. This review explores fatty acids derivatives from microalgae with applications in the field of renewable energies, biomaterials and pharmaceuticals. Nannochloropsis spp. (Eustigmatophyceae, Heterokontophyta) are particularly interesting for biotechnological applications since they grow at faster rates than many other species and possess hydroxy fatty acids and aliphatic cell wall polymers.

Highly Contaminated Marine Sediments Can Host Rare Bacterial Taxa Potentially Useful for Bioremediation

Coastal areas impacted by high anthropogenic pressures typically display sediment contamination by polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs). Microbial-based bioremediation represents a promising strategy for sediment reclamation, yet it frequently fails due to poor knowledge of the diversity and dynamics of the autochthonous microbial assemblages and to the inhibition of the target microbes in the contaminated matrix. In the present study, we used an integrated approach including a detailed environmental characterization, high-throughput sequencing and culturing to identify autochthonous bacteria with bioremediation potential in the sediments of Bagnoli-Coroglio (Gulf of Naples, Mediterranean Sea), a coastal area highly contaminated by PAHs, aliphatic hydrocarbons and HMs. The analysis of the benthic prokaryotic diversity showed that the distribution of the dominant taxon (Gammaproteobacteria) was mainly influenced by PAHs, As, and Cd concentrations. The other abundant taxa (including Alphaproteobacteria, Deltaproteobacteria, Bacteroidetes, Acidobacteria, Actinobacteria, NB1-j, Desulfobacterota, and Myxococcota) were mainly driven by sediment grain size and by Cu and Cr concentrations, while the rare taxa (i.e., each contributing <1%) by As and aliphatic hydrocarbons concentrations and by sediment redox potential. These results suggest a differential response of bacterial taxa to environmental features and chemical contamination and those different bacterial groups may be inhibited or promoted by different contaminants. This hypothesis was confirmed by culturing and isolating 80 bacterial strains using media highly enriched in PAHs, only nine of which were contextually resistant to high HM concentrations. Such resistant isolates represented novel Gammaproteobacteria strains affiliated to Vibrio, Pseudoalteromonas, and Agarivorans, which were only scarcely represented in their original assemblages. These findings suggest that rare but culturable bacterial strains resistant/tolerant to high levels of mixed contaminants can be promising candidates useful for the reclamation by bioaugmentation strategies of marine sediments that are highly contaminated with PAHs and HMs.

Cascabel: A Scalable and Versatile Amplicon Sequence Data Analysis Pipeline Delivering Reproducible and Documented Results

Marker gene sequencing of the rRNA operon (16S, 18S, ITS) or cytochrome c oxidase I (CO1) is a popular means to assess microbial communities of the environment, microbiomes associated with plants and animals, as well as communities of multicellular organisms via environmental DNA sequencing. Since this technique is based on sequencing a single gene, or even only parts of a single gene rather than the entire genome, the number of reads needed per sample to assess the microbial community structure is lower than that required for metagenome sequencing. This makes marker gene sequencing affordable to nearly any laboratory. Despite the relative ease and cost-efficiency of data generation, analyzing the resulting sequence data requires computational skills that may go beyond the standard repertoire of a current molecular biologist/ecologist. We have developed Cascabel, a scalable, flexible, and easy-to-use amplicon sequence data analysis pipeline, which uses Snakemake and a combination of existing and newly developed solutions for its computational steps. Cascabel takes the raw data as input and delivers a table of operational taxonomic units (OTUs) or Amplicon Sequence Variants (ASVs) in BIOM and text format and representative sequences. Cascabel is a highly versatile software that allows users to customize several steps of the pipeline, such as selecting from a set of OTU clustering methods or performing ASV analysis. In addition, we designed Cascabel to run in any linux/unix computing environment from desktop computers to computing servers making use of parallel processing if possible. The analyses and results are fully reproducible and documented in an HTML and optional pdf report. Cascabel is freely available at Github: https://github.com/AlejandroAb/CASCABEL.

Microalgal Metallothioneins and Phytochelatins and Their Potential Use in Bioremediation

The persistence of heavy metals (HMs) in the environment causes adverse effects to all living organisms; HMs accumulate along the food chain affecting different levels of biological organizations, from cells to tissues. HMs enter cells through transporter proteins and can bind to enzymes and nucleic acids interfering with their functioning. Strategies used by microalgae to minimize HM toxicity include the biosynthesis of metal-binding peptides that chelate metal cations inhibiting their activity. Metal-binding peptides include genetically encoded metallothioneins (MTs) and enzymatically produced phytochelatins (PCs). A number of techniques, including genetic engineering, focus on increasing the biosynthesis of MTs and PCs in microalgae. The present review reports the current knowledge on microalgal MTs and PCs and describes the state of art of their use for HM bioremediation and other putative biotechnological applications, also emphasizing on techniques aimed at increasing the cellular concentrations of MTs and PCs. In spite of the broad metabolic and chemical diversity of microalgae that are currently receiving increasing attention by biotechnological research, knowledge on MTs and PCs from these organisms is still limited to date.

Mantoniella beaufortii and Mantoniella baffinensis sp. nov. (Mamiellales, Mamiellophyceae), two new green algal species from the high arctic1

Members of the class Mamiellophyceae comprise species that can dominate picophytoplankton diversity in polar waters. Yet, polar species are often morphologically indistinguishable from temperate species, although clearly separated by molecular features. Here we examine four Mamiellophyceae strains from the Canadian Arctic. The 18S rRNA and Internal Transcribed Spacer 2 (ITS2) gene phylogeny place these strains within the family Mamiellaceae (Mamiellales, Mamiellophyceae) in two separate clades of the genus Mantoniella. ITS2 synapomorphies support their placement as two new species, Mantoniella beaufortii and Mantoniella baffinensis. Both species have round green cells with diameter between 3 and 5 μm, one long flagellum and a short flagellum (~1 μm) and are covered by spiderweb-like scales, making both species similar to other Mantoniella species. Morphologically, M. beaufortii and M. baffinensis are most similar to the cosmopolitan M. squamata with only minor differences in scale structure distinguishing them. Screening of global marine metabarcoding data sets indicates M. beaufortii has only been recorded in seawater and sea ice samples from the Arctic, while no environmental barcode matches M. baffinensis. Like other Mamiellophyceae genera that have distinct polar and temperate species, the polar distribution of these new species suggests they are cold or ice-adapted Mantoniella species.

Biosynthesis of Long Chain Alkyl Diols and Long Chain Alkenols in Nannochloropsis spp. (Eustigmatophyceae)

We investigated potential biosynthetic pathways of long chain alkenols (LCAs), long chain alkyl diols (LCDs), and long chain hydroxy fatty acids (LCHFAs) in Nannochloropsis oceanica and Nannochloropsis gaditana, by combining culturing experiments with genomic and transcriptomic analyses. Incubation of Nannochloropsis spp. in the dark for 1 week led to significant increases in the cellular concentrations of LCAs and LCDs in both species. Consistently, 13C-labelled substrate experiments confirmed that both LCA and LCD were actively produced in the dark from C14-18 fatty acids by either condensation or elongation/hydroxylation, although no enzymatic evidence was found for the former pathway. Nannochloropsis spp. did, however, contain (i) multiple polyketide synthases (PKSs) including one type (PKS-Clade II) that might catalyze incomplete fatty acid elongations leading to the formation of 3-OH-fatty acids, (ii) 3-hydroxyacyl dehydratases (HADs), which can possibly form Δ2/Δ3 monounsaturated fatty acids, and (iii) fatty acid elongases (FAEs) that could elongate 3-OH-fatty acids and Δ2/Δ3 monounsaturated fatty acids to longer products. The enzymes responsible for reduction of the long chain fatty acids to LCDs and LCAs are, however, unclear. A putative wax ester synthase/acyl coenzyme A (acyl-CoA): diacylglycerol acyltransferase is likely to be involved in the esterification of LCAs and LCDs in the cell wall. Our data thus provide useful insights in predicting the biosynthetic pathways of LCAs and LCDs in phytoplankton suggesting a key role of FAE and PKS enzymes.

Antioxidant and Photoprotection Networking in the Coastal Diatom Skeletonema marinoi

Little is known on the antioxidant activity modulation in microalgae, even less in diatoms. Antioxidant molecule concentrations and their modulation in microalgae has received little attention and the interconnection between light, photosynthesis, photoprotection, and antioxidant network in microalgae is still unclear. To fill this gap, we selected light as external forcing to drive physiological regulation and acclimation in the costal diatom Skeletonema marinoi. We investigated the role of light regime on the concentration of ascorbic acid, phenolic compounds and among them flavonoids and their connection with photoprotective mechanisms. We compared three high light conditions, differing in either light intensity or wave distribution, with two low light conditions, differing in photoperiod, and a prolonged darkness. The change in light distribution, from sinusoidal to square wave distribution was also investigated. Results revealed a strong link between photoprotection, mainly relied on xanthophyll cycle operation, and the antioxidant molecules and activity modulation. This study paves the way for further investigation on the antioxidant capacity of diatoms, which resulted to be strongly forced by light conditions, also in the view of their potential utilization in nutraceuticals or new functional cosmetic products.

Algal Remodeling in a Ubiquitous Planktonic Photosymbiosis

Photosymbiosis between single-celled hosts and microalgae is common in oceanic plankton, especially in oligotrophic surface waters. However, the functioning of this ecologically important cell-cell interaction and the subcellular mechanisms allowing the host to accommodate and benefit from its microalgae remain enigmatic. Here, using a combination of quantitative single-cell structural and chemical imaging techniques (FIB-SEM, nanoSIMS, Synchrotron X-ray fluorescence), we show that the structural organization, physiology, and trophic status of the algal symbionts (the haptophyte Phaeocystis) significantly change within their acantharian hosts compared to their free-living phase in culture. In symbiosis, algal cell division is blocked, photosynthesis is enhanced, and cell volume is increased by up to 10-fold with a higher number of plastids (from 2 to up to 30) and thylakoid membranes. The multiplication of plastids can lead to a 38-fold increase of the total plastid volume in a cell. Subcellular mapping of nutrients (nitrogen and phosphorous) and their stoichiometric ratios shows that symbiotic algae are impoverished in phosphorous and suggests a higher investment in energy-acquisition machinery rather than in growth. Nanoscale imaging also showed that the host supplies a substantial amount of trace metals (e.g., iron and cobalt), which are stored in algal vacuoles at high concentrations (up to 660 ppm). Sulfur mapping reveals a high concentration in algal vacuoles that may be a source of antioxidant molecules. Overall, this study unveils an unprecedented morphological and metabolic transformation of microalgae following their integration into a host, and it suggests that this widespread symbiosis is a farming strategy wherein the host engulfs and exploits microalgae.

Morphological and genetic diversity of Beaufort Sea diatoms with high contributions from the Chaetoceros neogracilis species complex

Seventy-five diatom strains isolated from the Beaufort Sea (Canadian Arctic) in the summer of 2009 were characterized by light and electron microscopy (SEM and TEM), as well as 18S and 28S rRNA gene sequencing. These strains group into 20 genotypes and 17 morphotypes and are affiliated with the genera Arcocellulus, Attheya, Chaetoceros, Cylindrotheca, Eucampia, Nitzschia, Porosira, Pseudo-nitzschia, Shionodiscus, Thalassiosira, and Synedropsis. Most of the species have a distribution confined to the northern/polar area. Chaetoceros neogracilis and Chaetoceros gelidus were the most represented taxa. Strains of C. neogracilis were morphologically similar and shared identical 18S rRNA gene sequences, but belonged to four distinct genetic clades based on 28S rRNA, ITS-1 and ITS-2 phylogenies. Secondary structure prediction revealed that these four clades differ in hemi-compensatory base changes (HCBCs) in paired positions of the ITS-2, suggesting their inability to interbreed. Reproductively isolated C. neogracilis genotypes can thus co-occur in summer phytoplankton communities in the Beaufort Sea. C. neogracilis generally occurred as single cells but also formed short colonies. It is phylogenetically distinct from an Antarctic species, erroneously identified in some previous studies as C. neogracilis, but named here as Chaetoceros sp. This work provides taxonomically validated sequences for 20 Arctic diatom taxa, which will facilitate future metabarcoding studies on phytoplankton in this region.

Pseudo-nitzschia arctica sp. nov., a new cold-water cryptic Pseudo-nitzschia species within the P. pseudodelicatissima complex

A new nontoxic Pseudo-nitzschia species belonging to the P. pseudodelicatissima complex, P. arctica, was isolated from different areas of the Arctic. The erection of P. arctica is mainly supported by molecular data, since the species shares identical ultrastructure with another species in the complex, P. fryxelliana, and represents a new case of crypticity within the genus. Despite their morphological similarity, the two species are not closely related in phylogenies based on LSU, ITS and rbcL. Interestingly, P. arctica is phylogenetically most closely related to P. granii and P. subcurvata, from which the species is, however, morphologically different. P. granii and P. subcurvata lack the central larger interspace which is one of the defining features of the P. pseudodelicatissima complex. The close genetic relationship between P. arctica and the two species P. granii and P. subcurvata is demonstrated by analysis of the secondary structure of ITS2 which revealed no compensatory base changes, two hemi-compensatory base changes, and two deletions in P. arctica with respect to the other two species. These findings emphasize that rates of morphological differentiation, molecular evolution and speciation are often incongruent for Pseudo-nitzschia species, resulting in a restricted phylogenetic value for taxonomic characters used to discriminate species. The description of a new cryptic species, widely distributed in the Arctic and potentially representing an endemic component of the Arctic diatom flora, reinforces the idea of the existence of noncosmopolitan Pseudo-nitzschia species and highlights the need for combined morphological and molecular analyses to assess the distributional patterns of phytoplankton species.

Transcriptome analyses to investigate symbiotic relationships between marine protists

Rhizaria are an important component of oceanic plankton communities worldwide. A number of species harbor eukaryotic microalgal symbionts, which are horizontally acquired in the environment at each generation. Although these photosymbioses are determinant for Rhizaria ability to thrive in oceanic ecosystems, the mechanisms for symbiotic interactions are unclear. Using high-throughput sequencing technology (i.e., 454), we generated large Expressed Sequence Tag (EST) datasets from four uncultured Rhizaria, an acantharian (Amphilonche elongata), two polycystines (Collozoum sp. and Spongosphaera streptacantha), and one phaeodarian (Aulacantha scolymantha). We assessed the main genetic features of the host/symbionts consortium (i.e., the holobiont) transcriptomes and found rRNA sequences affiliated to a wide range of bacteria and protists in all samples, suggesting that diverse microbial communities are associated with the holobionts. A particular focus was then carried out to search for genes potentially involved in symbiotic processes such as the presence of c-type lectins-coding genes, which are proteins that play a role in cell recognition among eukaryotes. Unigenes coding putative c-type lectin domains (CTLD) were found in the species bearing photosynthetic symbionts (A. elongata, Collozoum sp., and S. streptacantha) but not in the non-symbiotic one (A. scolymantha). More particularly, phylogenetic analyses group CTLDs from A. elongata and Collozoum sp. on a distinct branch from S. streptacantha CTLDs, which contained carbohydrate-binding motifs typically observed in other marine photosymbiosis. Our data suggest that similarly to other well-known marine photosymbiosis involving metazoans, the interactions of glycans with c-type lectins is likely involved in modulation of the host/symbiont specific recognition in Radiolaria.

The influence of parity on multinodular goiter prevalence in areas with moderate iodine deficiency

Despite the observation that parity may increase the risk of thyroid carcinoma, very few studies have investigated the possible repercussion of parity on thyroid benign pathology. Recently, parity has been identified as one of the factors contributing to a larger thyroid size in healthy females. The aim of this work was to investigate a possible role for parity on the prevalence of multinodular goiter in iodine deficient areas. For this purpose, the reproductive histories of 2 cohorts of women, normal (Group I, 235 cases) and non-toxic multinodular goiter (NTMNG) affected (Group II, 274 cases) were compared. All subjects were euthyroid and had no previous history of thyroid function abnormalities. The number of full-term previous pregnancies (2.55+/-0.11 vs 1.77+/-0.10) and age (47.7+/-0.76 vs 42.3+/-0.83 yr) were found significantly higher (p<0.001) in multinodular goiter (MNG) patients than controls. Parity and age were found to be directly correlated (p<0.001), nevertheless the partial correlation coefficients demonstrated an independent and statistically significant difference for both variables between normal and NTMNG. Therefore, the independent effects of parity and age were further investigated. The effect of age on NTMNG prevalence seems to be weaker, in fact significant differences (p<0.001) for age between patients and controls were detected only when the effect of parity was absent (nulliparous), while with increasing gestations the effect of age disappeared. Our results indicate that age plays a minor role compared to parity which can therefore be considered as a stronger risk factor. In conclusion, the present study shows that, at least in iodine deficient regions, non-toxic multinodular goiter women show a statistically significant higher parity rate than healthy controls. Age may play a certain role but only when additional stronger risk factors are absent.

Parity as a thyroid size-determining factor in areas with moderate iodine deficiency

Among the factors that may influence thyroid size, pregnancy and its goitrogenic effect have been widely investigated, but thyroid volume and pregnancy have never been compared retrospectively, and there are no data on the possible relationship between thyroid size and parity. The purpose of this work was to evaluate the effects of pregnancy on thyroid volume in a moderate iodine deficiency area, to assess the possibility of a relationship between thyroid size and parity status in healthy females. A group of 208 nongoitrous healthy women underwent thyroid volume estimation by ultrasound examination. All subjects were euthyroid and negative for thyroid autoantibodies. They were assigned to different groups, according to the number of completed pregnancies. Five groups were formed (0, 1, 2, 3, 4 or more term pregnancies). Mean thyroid volume increased progressively among the groups: group 0 (14.8 +/- 0.7 mL); group I (16.0 +/- 0.9 mL); group II (17.1 +/- 0.6 mL); group III (18.2 +/- 0.6 mL); group IV (20.3 +/- 0.9 mL). The increment in thyroid volume was statistically significant between group 0 and groups III (P: < 0.01) and IV (P: < 0.001), and also between group I and group IV (P: < 0. 05). No independent effect of body weight and age on thyroid volume was seen. Our results indicate that, in an area with moderate iodine deficiency, the goitrogenic effect of pregnancy is not fully reversible. Moreover, the statistically significant increase in thyroid volume, observed in relation to parity, is the first clinical demonstration of a cumulative goitrogenic effect of successive pregnancies, providing a strong argument to increase the iodine supply during pregnancy, even in conditions with moderate iodine deficiency.

Transcatheter arterial chemoembolization for hepatocellular carcinoma in patients with cirrhosis: evaluation of damage to nontumorous liver tissue-long-term prospective study

PURPOSE

To evaluate damage to cirrhotic liver tissue after transcatheter arterial chemoembolization (TACE) in patients with hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

TACE was performed in 111 patients with HCC that involved less than 30% of the liver. Baseline liver function was evaluated with Child-Pugh scores and other indicators. Eighty-two patients had Child-Pugh class A disease, 27 had class B disease, and two had class C disease. All patients underwent chemotherapy followed by gelatin sponge particle embolization in the proper ("complete" embolization; n = 69) or right or left main ("partial" embolization; n = 42) hepatic artery. Liver function was assessed 4 months later, and 95 patients underwent a second TACE (complete embolization in 57, partial in 38). Liver function was again assessed 4 months later in 60 patients.

RESULTS

No patient died. Child-Pugh scores increased in all patients from a mean 5.96 to 6.28 (not significant) and 6.51 (P =. 05) after first and second TACEs, respectively. In patients with class A disease, scores increased from a mean 5.37 to 5.73 (P =.01) and 5.89 (P =.001) after first and second TACEs, respectively; in patients with class B disease, scores changed from a mean of 7.48 to 7.67 and 7.30 after first and second TACEs, respectively (not significant).

CONCLUSION

TACE does not induce significant long-term worsening of liver function in patients with class A or B cirrhosis.

Congenital absence of the internal carotid artery

We report three cases of congenital absence of an internal carotid artery (ICA), diagnosed incidentally by digital subtraction angiography. The analysis of the cases is based on the classification of segmental ICA agenesis proposed by Lasjaunias and Berenstein. Usually the patients with this rare vascular anomaly are asymptomatic; some may have symptoms related to cerebrovascular insufficiency, compression by enlarged intracranial collateral vessels, or complications associated with cerebral aneurysms. Diagnosis of congenital absence of ICA is made by skull base computed tomography (CT) scan, CT and magnetic resonance angiography, and conventional or digital subtraction angiography.

Congenital intrahepatic portosystemic shunt

The authors report a congenital intrahepatic portosystemic shunt detected by angiography in a young patient with acute onset of hyperammoniemia and hepatic encephalopathy.

[Stenosis-occlusion of the carotid bifurcation. Angiography with MR and contrast media versus digital angiography]

PURPOSE

To evaluate the comparative sensitivity, specificity and diagnostic accuracy of contrast enhanced magnetic resonance angiography (CE MRA) and digital subtraction angiography (DSA) in the study of carotid bifurcation stenoses.

MATERIAL AND METHODS

Twenty-three patients with suspected cerebrovascular insufficiency by carotid stenosis were examined with CE MRA and DSA within 24 hours of each other. A 1.5 superconductive unit (Signa, General Electric) was used for CE MRA; fast spoiled gradient echo recalled (SPGR) images were acquired on the coronal plane 12 s after contrast medium injection, with the following parameters: TR/TE/FA 8/1/60, MA 256 x 128, NEX 1, FOV 18 x 13, slices/slab 28, slice thickness 1 mm, TA 32 s. The images were postprocessed with the maximum intensity projection (MIP) and the targeted MIP algorithms. A Siemens Politron 1000 VR unit was used for DSA examinations.

RESULTS

DSA diagnosed 21 true positives, namely 4 grade II, 4 grade III, 10 grade IV and 3 grade V stenoses. CE MRA scored 100% in stenosis identification and grading, accurately diagnosing all the true negatives and the true positives and was always in agreement with DSA as to stenosis site.

CONCLUSION

CE MRA can be considered the technique of choice to study stenosis occlusion in the epiaortic vessels, because it permits a rapid panoramic study of the neck vessels and accurate stenosis grading with similar patterns to those of DSA. Thus, CE MRA appears to be a valid alternative to DSA.

Treatment of hepatocellular carcinoma: a single-center experience

PURPOSE

The comparative efficacy of transcatheter arterial chemoembolization (TACE) and percutaneous ethanol injection (PEI) in the treatment of hepatocellular carcinoma (HCC) was investigated.

METHODS

Two hundred and sixty consecutive patients were retrospectively analyzed: 156 had received between one and six chemoembolization sessions at 3-month intervals, 33 had had PEI, and the remaining 71 patients refused any treatment. The follow-up ranged from 3 to 36 months. Survival rates were statistically analyzed by life-table analysis.

RESULTS

Patients' survival was affected by the number of nodules and by the Child's and Okuda's classes; no relationship was found between survival rates and the histologic grade or vascular supply of the tumor. In the case of a single lesion of Okuda's class I, TACE was more effective than PEI. In multifocal HCC, TACE was better than no treatment in Okuda's class I and Child's class A.

CONCLUSION

We suggest TACE as the treatment of choice in Child A or Okuda I patients with multifocal HCCs; it seems of little help in Child B-C or Okuda II-III patients.

[Interventional radiology in thoracic emergencies]

There are numerous clinical situations in which interventional angiography fully reveals its two-fold diagnostic and therapeutic value. The present review focuses attention on the use of such procedures in certain thoracic emergencies. Indications, diagnostic results and therapeutic advantages are examined together with possible complications. Pulmonary embolism is a serious circulatory condition that is often difficult to diagnose because of the lack of specificity of its accompanying symptoms. In these cases the role of the angiographic radiologist is often three-fold: diagnosis, therapy (possibility of carrying out locoregional thrombolysis), and prophylaxis (positioning of caval filters that prevent the migration of thrombi). Haemoptysis may arise from both the pulmonary and bronchial vessels and may be caused by various pathologies (cancer, angiodysplasia, vasculitis, aspergillosis). Angiographic study in such cases is indispensable for identifying the source of bleeding and for arresting, using embolising material, haemorrhage that it is no longer possible to control with other therapeutic modalities. Foreign bodies held in the vascular tree are in the main fragments of catheters detached accidentally or as a result of incorrect manoeuvres or for defects of construction of the material. Their removal is possible today by using, percutaneously, angiographic techniques (snare loop, basket, hook system, balloon catheters) which make it possible to hook up the fragment and remove it.

Sleep deprivation in the rat: XIX. Effects of thyroxine administration

Chronic total sleep deprivation (TSD) in the rat produces an initial elevation and then declining body temperatures, increasing metabolic rate and eventual death. Because TSD rats will engage in warming behavior, one hypothesis is that the metabolic increase is an unsuccessful attempt at warming to combat a lethal hypothermia. However, TSD rats also undergo weight loss and progressive deterioration of skin and fur, suggesting TSD-induced pathological catabolic activity, possibly secondary to increased metabolic rate, that could be lethal. To evaluate these alternatives, the metabolic rate of rats was increased by thyroxine (T4) treatment while subjecting them to TSD. Compared to TSD rats not given T4, they had higher metabolic rates, higher body temperatures and reduced warming behavior, but their survival period was 37% shorter. Thus, it is unlikely that hypothermia is the cause of death in TSD rats. Weight and appearance declined more rapidly in T4-treated rats, but at the same proportions of survival time, skin pathology and decline in appearance were less evident in T4-treated rats than in TSD rats not given T4. Thus, there is some doubt whether a general pathological catabolic process is the cause of death. It is also possible that a specific morbid process normally reversed by sleep was accelerated by T4 administration.

[Treatment of primary hepatocarcinoma with chemoembolization and alcohol injection. Personal experience]

The comparative efficacy of transcatheter arterial chemoembolization and percutaneous ethanol injection (PEI) in the treatment of hepatocellular carcinoma (HCC) was investigated in a series of 243 consecutive patients: 146 of them were submitted to 1-6 chemoembolization sessions at 1 and 3 months' intervals and 30 to PEI; the remaining 67 patients refused any treatment. The follow-up ranged 3 to 36 months. Survival rates were statistically analyzed with the life table analysis. Patients' survival was affected by the number of nodules and by Child's and Okuda's classes; no relationship was found between survival rates and histologic grade or nodule vascular feeding. In case of single lesions, chemoembolization was more effective than PEI in Okuda's class I. In case of multifocal HCC, chemoembolization was better than no treatment in Okuda's class I and Child's class A. In conclusion, we suggest chemoembolization as the treatment of choice in Child A or Okuda I patients with multifocal HCCs, while its use seems of little help in Child B-C or Okuda II-III patients. In case of unifocal HCC, PEI or surgical resection should be combined with chemoembolization.

[Primary hepatocarcinoma. Diagnostic imaging and chemoembolization]

The diagnostic and therapeutic approach by means of transcatheter arterial chemoembolization is analyzed in 100 patients affected with hepatocellular carcinoma (HCC): in all patients the HCC had been diagnosed by means of US-guided fine-needle biopsy: 75 of 100 patients were in Child A class, 24 in Child B and 1 in Child C class. The most sensitive imaging technique to identify HCC proved to be angiography (95%); post-Lipiodol CT was also of great value to stage the disease. The authors suggest a diagnostic-therapeutic approach including angiography and simultaneous chemoembolization right after US-guided biopsy, avoiding conventional CT; such a protocol allows high diagnostic accuracy at a lower cost. Chemoembolization proved to be a safe technique, with a low incidence of mortality and complications; the latter were easy to treat by medical therapy. The follow-up data relative to 39 of 100 patients who underwent 2 or more chemoembolization treatments prove the latter to be a valuable technique relative to both the evolution of HCC nodules (in 18/21 patients with single lesions and in 9/18 patients with multiple lesions, lesion size was unchanged or decreased) and to survival rates (70% in 65 patients followed-up 1 year at least); on the whole, 77 of 100 patients are still alive.

[Transluminal therapy of stenosing lesions of the supra-aortic vessels. Personal experience]

Percutaneous transluminal angioplasty (PTA) is commonly used to treat peripheral vascular diseases, but its use has recently spread to the treatment of stenotic lesions involving the supra-aortic vessels. The authors report their initial experience in 10 patients with left subclavian artery stenoses--8 of them treated with PTA and 2 with PTA and vascular stenting--and two more patients with fibromuscular stenosis of the internal carotid artery (ICA), which was treated by means of PTA. In the authors' opinion, PTA can be considered the procedure of choice to treat the stenotic lesions of the supra-aortic vessels. Intravascular stents can be extremely useful to prevent post-PTA restenosis, but further experience and probably further technological refinements are needed. To conclude, PTA of ICA is an effective method in selected cases--e.g., in the patients with symptomatic hemodynamic lesions and low risk of embolism, in the patients with difficult surgical access or in the event of high anesthesiological and/or surgical morbidity.

Secretion of growth hormone releasing hormone in obese children

We have evaluated baseline and l-dopa-stimulated peripheral growth hormone releasing hormone (pGHRH) secretion in 6 obese pre-pubertal children and in 7 age-matched controls. Baseline pGHRH levels were no different between obese (36.6 +/- 9.8 pg/ml, mean +/- SE) and control children (40.6 +/- 10.1 pg/ml). Administration of l-dopa (500 mg po) caused a significant increase of pGHRH levels in both the obese (65.3 +/- 19.8 pg/ml, p less than 0.05) and the control children (84.1 +/- 10.0 pg/ml, p less than 0.003). Mean peak pGHRH levels after l-dopa were not significantly different between the two groups, whereas mean peak GH levels were significantly lower (p less than 0.05) in the obese (7.9 +/- 1.9 ng/ml) than in the control children (20.5 +/- 4.9 ng/ml). We conclude that despite reduced GH secretion, obese children have normal baseline and l-dopa stimulated pGHRH levels.

Therapy of Graves' disease with sodium ipodate is associated with a high recurrence rate of hyperthyroidism

To evaluate the long-term efficacy of sodium ipodate (IPO) in the treatment of hyperthyroid Graves' disease, we studied 12 consecutive patients with Graves' hyperthyroidism treated only with 500 mg IPO po daily for several weeks to 22 months. Serum thyroid hormone concentrations markedly decreased and serum free T3 values normalized in all patients within 7 days of therapy. Five patients (42%, Group 1) were euthyroid after 6 weeks of IPO treatment and remained so until IPO was discontinued after 22 months. Recurrence of hyperthyroidism after drug withdrawal occurred in only one of these Group 1 patients, who was promptly responsive to a second course of IPO. In contrast, seven of 12 patients (58%, Group 2) relapsed with recurrent hyperthyroidism between 14 and 42 days of IPO therapy. After IPO was withdrawn, these Group 2 patients were treated with methimazole (20-30 mg/day, initial dose), but the therapeutic response was poor and delayed. Two patients were still hyperthyroid after 6 months of methimazole treatment. Elevated serum FT3 concentrations were observed in the Group 2 patients at 21 days following the early normalization of serum FT3 concentrations. No changes in serum thyroglobulin and thyroid microsomal and TSH-receptor autoantibody titers were observed in either groups during IPO therapy. In conclusion, the results of the present study demonstrate that IPO rapidly restores euthyroidism, but its prolonged administration is associated with a high rate of relapse of hyperthyroidism and a poor response to subsequent methimazole treatment and that long-term IPO administration does not affect humoral markers of thyroid autoimmunity.

Screening of nineteen unrelated families with generalized resistance to thyroid hormone for known point mutations in the thyroid hormone receptor beta gene and the detection of a new mutation

Generalized resistance to thyroid hormone (GRTH) is a syndrome characterized by impaired tissue responsiveness to thyroid hormone. Two distinct point mutations in the hormone binding domain of the thyroid hormone receptor (TR) beta have recently been identified in two unrelated families with GRTH. One, Mf, involves a replacement of the normal glycine-345 for arginine in exon 7 and another, Mh, replaces the normal proline-453 for histidine in exon 8. To probe for the presence of the Mf and Mh defect in 19 unrelated families with GRTH, we applied separate polymerase chain reactions using allele-specific oligonucleotide primers containing the normal and each of the two mutant nucleotides at the 3'-position. A total of 24 affected subjects and 13 normal family members were studied. The mode of inheritance was dominant in 13 families, was unknown in 5 families, and was clearly recessive in 1 family in which only the consanguineous subjects were affected. Primers containing the substitutions specific for Mf and Mh amplified exons 7 and 8, respectively, only in affected members of each of the two index families. Primers containing the normal sequences amplified exons 7 and 8 of the TR beta gene in all subjects except affected members of one family. In this family with recessively inherited GRTH, neither exon could be amplified using any combinations of primers and DNA blot revealed absence of all coding exons. These results indicate a major deletion of the TR beta gene, including both DNA and hormone binding domains. Since heterozygous members of this family are not affected, the presence of a single normal allele is sufficient for normal function of the TR beta. These data also support the hypothesis that in the dominant mode of GRTH inheritance the presence of an abnormal TR beta interferes with the function of the normal TR beta. Distinct mutations are probably responsible for GRTH in unrelated families.

Neonatal detection of generalized resistance to thyroid hormone

Generalized resistance to thyroid hormone (GRTH) is an inherited disease that is usually suspected when elevated serum thyroid hormone levels are associated with nonsuppressed thyrotropin. Often these test results are obtained because of short stature, decreased intelligence, and/or hyperactivity with learning disability noted in childhood and adolescence, or because of goiter in adulthood. We detected GRTH at birth by analysis of blood obtained during routine neonatal screening. The proposita, born to a mother with GRTH, had a thyrotropin level of 26 mU/L and a corresponding thyroxine concentration of 656 nmol/L (normal, 84 to 232 nmol/L). Administration of thyroid hormone in doses eightfold to 10-fold above replacement levels (liothyronine sodium, 21 micrograms/kg per day, and levothyroxine sodium, 44 micrograms/kg per day) were required to reduce serum thyrotropin to normal levels without induction of hypermetabolism. This case, and the retrospective finding of high thyroxine levels in five newborns subsequently diagnosed as having GRTH, suggest that measurement of thyroxine at birth, in conjunction with thyrotropin, could allow the early detection of GRTH.

Effect of total sleep deprivation on 5'-deiodinase activity of rat brown adipose tissue

Prolonged sleep deprivation of the rat produces a progressive increase in energy expenditure and an eventual decrease in body temperature, which suggests a profound derangement in thermoregulation. Because increased thermogenic activity in brown adipose tissue (BAT) is a likely mechanism mediating the observed increase in energy expenditure, we focused our attention on the effect of total sleep deprivation on BAT type II 5'-deiodinase (5'D-II), since its activation indicates BAT stimulation and is essential for full BAT thermogenic response. Five euthyroid rats were subjected to total (92%) sleep deprivation (euD-rats). Sharing the sleep deprivation apparatus, yoked control rats (euC-rats) received the same degree of physical stimulation as the D-rats, but were only partially (25%) sleep deprived. Additional cage controls (euCC-rats) were housed in the same room. Since during sleep deprivation the animals undergo a reduction in plasma T4 concentration and inability to maintain body temperature heralds death, an identical study was performed in five trios of hyperthyroid rats (hyperD-, hyperC-, and hyper CC-rats) given daily ip injections of 15 micrograms T4/100 g BW, 10 days before and throughout the deprivation period. Experiments were carried out at an ambient temperature of 29 C, close to thermoneutrality for rats. Sleep deprivation in hyperD-rats was maintained until death seemed imminent (9-14 days), and in euD-rats for 12-15 days. Sleep deprivation induced a significant increase in BAT 5'D-II activity in both hyperD- and euD-rats compared with that in euCC-rats (P less than 0.01). BAT 5'D-II in euC-rats was also significantly higher than that in euCC-rats (P less than 0.05), probably because they were partially sleep deprived. BAT 5'D-II activity in hyperD-rats was increased compared to that in both hyperC- and hyperCC-rats (P less than 0.05), in which the activity was slightly but not significantly lower than that in euCC-rats. No significant differences were observed in liver and kidney type I 5'-D (5'D-I) and in pituitary 5'D-II among euD-rats, euC-rats, and euCC-rats. As expected, the hyperthyroid groups (hyperD-rats, hyperC-rats, and hyperCC-rats) had significantly higher kidney 5'D-I and lower pituitary 5'D-II than the euCC-rats. Liver 5'D-I was also significantly increased in the hyperC-rats and hyperCC-rats, but not in the hyperD-rats. These observations indicate that total sleep deprivation is associated with a marked increase in BAT 5'D-II activity in both euthyroid and hyperthyroid rats.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of the antileukemic drug L-asparaginase on sex hormone-binding globulin: studies in vivo and in vitro

L-asparaginase, an antineoplastic drug used in the treatment of acute lymphoblastic leukemia (ALL), has been previously shown to inhibit the hepatic synthesis of thyroxine-binding globulin (TBG). In two children treated by this drug for ALL, a dramatic decrease in serum sex hormone-binding globulin (SHBG) concentrations was also observed. Serum SHBG levels were still below normal 10 days after L-asparaginase withdrawal. To ascertain whether this reduction was due to the inhibition of SHBG synthesis, SHBG was measured by an immunoradiometric assay (IRMA) in the medium from human hepatoblastoma-derived cells, Hep G2 cells, grown in the absence or presence of graded amounts of the drug from 0.1 nM to 0.1 mM. The results showed a dose-dependent inhibition of SHBG synthesis, with a 50% reduction of SHBG in the medium, assayed by IRMA, using 250 nM L-asparaginase. Furthermore, a time-dependent inhibition was observed using a fixed concentration of the drug (50 nM) added for variable time intervals (1-4 days). These data suggest that the changes observed in vivo are likely due to the inhibitory effect exerted by the drug on SHBG synthesis. This action is not specific, but is part of a general effect at the hepatic level.

[ERCP in the diagnosis of bilio-pancreatic pathology. Comparison with echography and CT]

The authors have evaluated both sensitivity and specificity of ERCP in comparison with other imaging methods, such as US and CT, on the basis of a study of 63 patients with suspected pancreatobiliary pathologies. Our results show ERCP of chronic pancreatitis to have 83% sensitivity and 66% specificity. As for biliary pathologies, sensitivity was 94% and specificity 88%. In pancreatic pathologies, CT sensitivity was 99% and its specificity was 70%. The combined use of ERCP and CT determines a considerable rise in the percentages, and allows the evaluation of both the excretory tree and the parenchyma. As for biliary pathologies, the role of ERCP is fundamental, since its combination with the other methods (CT: sensitivity 72%, specificity 3.5%; US: sensitivity 70%, specificity 3.5%) has not determined but a slight increase in sensitivity, and no significant increase in specificity.

The effect of flutamide on basal and ACTH-stimulated plasma levels of adrenal androgens in patients with advanced prostate cancer

The effect of flutamide on basal and ACTH-stimulated plasma levels of adrenal androgens was investigated in 6 patients with untreated advanced prostate cancer, aged 52-75 yr. Flutamide was administered (250 mg three times daily) for 10 days; before and after treatment, a synthetic ACTH1-24 stimulation test (250 micrograms im, with blood sampling immediately before and 60 min after the stimulus) was performed. Basal plasma 17OH-pregnenolone (delta 5-17OHP), 170H-progesterone (delta 4-17OHP), androstenedione (A), dehydroepiandrosterone (DHEA) and its sulphate (DHEAS) were unchanged by flutamide treatment. In contrast, basal plasma testosterone (T) concentrations significantly increased (p less than 0.05). The response of cortisol delta 4-17OHP, delta 5-17OHP, A and DHEA to ACTH, as well as the ACTH-stimulated delta 5-17OHP/delta 4-17OHP, delta 5-17OHP/DHEA, delta 4-17OHP/A and DHEA/A ratios, were unchanged by flutamide treatment. These findings indicate that: a) Short-term flutamide administration enhances testicular steroidogenesis, via augmented LH pulse frequency; b) Adrenal steroidogenesis seems to be not affected by the drug, since ACTH-stimulated plasma levels of adrenal androgens and precursors/products ratios were unchanged.

Fibrinogen and fibrinolytic activity in hyperthyroidism before and after antithyroid treatment

Plasma concentration of fibrinogen and B beta 15-42, a specific product of fibrinogen metabolism induced by plasmin, were measured in a group of patients with untreated hyperthyroidism and in controls. Significantly increased plasma levels of both parameters were observed in hyperthyroid patients. The restoration of euthyroidism either by antithyroid drug or by radioiodine caused a significant decrease of fibrinogen and B beta 15-42. These data indicate that hyperthyroidism is another clinical condition associated with increased concentration of fibrinogen and B beta 15-42.

The effect of altered thyroid function on serum fructosamine concentrations

The effect of altered thyroid function on serum fructosamine concentrations was investigated in 31 untreated hyperthyroid patients, 18 short-term hypothyroid patients (i.e., 20 days after withdrawal of thyroid hormone suppressive therapy for thyroid cancer), 7 untreated long-term hypothyroid patients, and 25 age-matched normal controls. No differences in serum fructosamine concentrations were observed between hyperthyroid patients and normal controls; conversely, serum fructosamine concentrations were significantly higher both in short-term and in long-term hypothyroid patients than those found in normal controls. Furthermore, long-term hypothyroid patients showed significantly higher serum fructosamine concentrations than short-term hypothyroid patients. L-Thyroxine (L-T4), replacement therapy in two hypothyroid patients, resulted in a marked decrease in serum fructosamine concentrations. In seven hyperthyroid patients, the restoration of euthyroidism with antithyroid drug therapy was associated with no significant changes in serum fructosamine concentrations. The results of the present study indicate that hypothyroidism is associated with a marked increase in serum fructosamine concentrations. This alteration does not appear to be the consequence of gross abnormalities in plasma protein or glucose metabolism. The duration of hypothyroidism seems to be an important factor, even though the mechanism underlying this alteration remains at present unexplained. These results also suggest that caution must be used in the interpretation of elevated serum fructosamine concentrations as an index of the metabolic control of diabetes mellitus in the presence of hypothyroidism.

Absence of serum thyroid hormone autoantibodies in patients chronically treated with amiodarone

The role of iodine in the pathogenesis of thyroid hormone autoantibodies (THAA) was evaluated in a large series (n = 223) of patients submitted to chronic treatment (3-36 months) with the iodine-rich drug, amiodarone. Positive anti-T3 autoantibody (AbT3) tests were found only in one patient, whereas tests for anti-T4 autoantibody (AbT4) were negative in all cases. Likewise, the incidence of THAA in the control groups of patients with spontaneous thyroid disorders was low. The overall prevalence of THAA in the present series of 803 patients was 1.2% for AbT3 and 0.1% for AbT4. The present data strongly suggest that iodine plays a minor role, if any, in the occurrence of THAA.

Short term effects of flutamide administration on hypothalamic-pituitary-testicular axis in man

The effect of short term administration of flutamide on the hypothalamic-pituitary-gonadal axis was studied in six patients with advanced prostate cancer (C2 stage). Flutamide significantly increased LH pulse frequency in all patients (p less than 0.05 by Wilcoxon's test). The FSH pulse analysis disclosed a similar pattern of LH. Plasma IC-T clearly increased following flutamide therapy; mean IC-T values were 2.67 +/- 0.47 ng./ml. and 4.67 +/- 0.62 ng./ml. before and after flutamide administration, respectively (p less than 0.05 by paired Student's t test). Our study demonstrates that flutamide acts in humans as a selective and specific antiandrogen compound.

Short-term met-hGH infusion inhibits somatotroph response to growth hormone releasing hormone (1-44)

To determine whether the short-term administration of growth hormone inhibits pituitary responsiveness to h-GHRH we measured the somatotroph response to h-GHRH-44 (0.3 micrograms/kg) stimulation in ten normal subjects from the third to the fifth hour of an infusion of met-hGH (2 micrograms/kg/h) or saline. Insulin, insulin-like growth factors (IGF), somatomedins, free fatty acids (FFA), glycerol, and glucose levels also were assessed during the first 3 hours of infusion. Steady-state GH levels of 5 to 20 ng/mL were achieved during met-hGH infusion. No significant changes in IGF, insulin, or glucose levels measured at the beginning and again after three hours of infusion occurred within or between conditions. Infusion of met-hGH was associated with a significantly greater increase in FFA levels (69 +/- 50 mumol/L following saline v 433 +/- 57 mumol/L following three hours of met-hGH infusion (P less than .001)). The somatotroph response to h-GHRH-44 was significantly blunted during met-hGH infusion (incremental area under the GH/time curve decreasing from 1,196 +/- 183 (ng/mL) X min to 380 +/- 139 (ng/mL) X min (P less than .005)). These data demonstrate that this blunting can occur following short-term exogenous GH administration and at serum GH levels comparable to those achieved during naturally occurring bursts of GH secretion. They also suggest that acute mediation of GH release must occur, at least in part, at the pituitary somatotroph level and that IGFs and/or insulin may not be the primary inhibitors. This phenomenon may be directly or indirectly due to GH-dependent metabolic factors such as FFA or glycerol.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of the nocturnal serum thyrotropin (TSH) surge, as assessed by TSH ultrasensitive assay, in patients receiving long term L-thyroxine suppression therapy and in patients with various thyroid disorders

Circadian variations of serum TSH concentrations have been reported, with higher values occurring in the late evening or early morning. In patients receiving long term L-T4 suppression therapy, it may be important to achieve suppression of TSH secretion throughout the day. To investigate whether undetectable serum TSH values in the morning are associated with undetectable serum TSH levels at night, serum TSH concentrations were measured by an ultrasensitive immunoradiometric assay in 16 normal subjects, 20 hyperthyroid patients, 10 patients with primary hypothyroidism (either untreated or inadequately treated with L-T4), 1 patient with central hypothyroidism, 10 patients with nontoxic nodular goiter, 5 patients with functioning thyroid adenoma, 20 patients receiving L-T4 replacement therapy, and 30 patients receiving L-T4 suppression. In 6 subjects blood was drawn at hourly intervals for 24 h; in 2 normal subjects a major TSH surge occurred between 2300-0100 h, with other minor peaks, and the same pattern was found in two patients receiving L-T4 replacement, whereas in 2 patients receiving L-T4 suppression, serum TSH was constantly below the limit of detection of the assay (i.e. less than 0.07 mU/L). In the remaining patients blood was drawn at hourly intervals between 2300-0200 h and on the next morning before (0830-0900 h) and 30 min after iv TRH administration. In normal subjects, in patients receiving L-T4 replacement therapy, and in hypothyroid patients, serum TSH values at night were higher than in the morning, with normal responses to TRH in the first 2 groups and exaggerated responses in the latter. The patient with central hypothyroidism had no nocturnal TSH surge and no TSH response to TRH. In all hyperthyroid patients, serum TSH was undetectable both at night and during the day, and none had a serum TSH response to TRH. Among patients with nontoxic goiter, 7 had detectable serum TSH in the morning, with higher values at night, and a normal response to TRH; the remainder had undetectable serum TSH both at night and in the morning, and subnormal or absent TSH responses to TRH. All 5 patients with a functioning thyroid adenoma had undetectable serum TSH levels in the morning and during the night, and subnormal or absent TSH responses to TRH. Of the 30 patients receiving long term (greater than 6 months) L-T4 suppression therapy, 28 had undetectable serum TSH both during the night and in the morning and unresponsiveness to TRH.(ABSTRACT TRUNCATED AT 400 WORDS)

Diagnosis of amiodarone-iodine-induced thyrotoxicosis(AIIT) associated with severe nonthyroidal illness

A rare case of amiodarone-iodine-induced thyrotoxicosis (AIIT) associated with nonthyroidal illness is reported. Serum total thyroxine (TT4) and free T4 (FT4) concentrations were elevated and serum TSH was undetectable as frequently observed also in euthyroid amiodarone-treated patients. At variance with common forms of AIIT, serum total triiodothyronine (TT3) was reduced due to low-T3 syndrome. The laboratory diagnosis was made on the basis of elevated free T3 (FT3) levels. Thus, in patients with severe nonthyroidal illness submitted to chronic amiodarone treatment, thyroid status can only be determined by free hormone measurement, particularly FT3 in the case of thyrotoxicosis.