[Diagnosis of thoracic outlet syndrome by angio-MRI]. / Diagnóstico por angiorresonancia magnética del síndrome del estrecho torácico superior.

OBJECTIVE: To evaluate the sequences and maneuvers recommended for the study of the thoracic outlet syndrome (TOS) and the usefulness of magnetic resonance imaging (MRI) in demonstrating its etiology. MATERIAL AND METHODS: We present a study of eight patients with clinical presentation suggestive of TOS. All underwent MRI, gadolinium-enhanced angio-MRI with the arms extended along the body and with postural maneuvers of abduction and elevation of the arms, plain-film chest x-rays, and digital angiography. The anatomic characteristics of the superior aperture of the thorax were analyzed on both sides before and during postural maneuvering. Likewise, the permeability of the vessels and integrity of the brachial plexus was studied. RESULTS: In two cases, angio-MRI demonstrated thrombosis, of the subclavian artery in one case and of the subclavian vein in the other, caused by a cervical rib, which was confirmed at plain-film chest x-ray. In one case, angio-MRI demonstrated stenosis of the subclavian artery on abduction, secondary to hypertrophy of the anterior scalene muscle, and digital angiography showed the same findings. In two cases, angio-MRI showed vascular thrombosis, arterial in one case and venous in the other, without evidence of anatomic anomalies; these findings were confirmed at digital angiography. In two cases, no pathological findings were observed at MRI, angio-MRI, or digital angiography. In one case, MRI showed the presence of a cervical rib without vascular repercussions. CONCLUSION: Gadolinium-enhanced angio-MRI is useful in the evaluation of TOS. It is important to examine patients at rest and during different postural maneuvers. In many cases it is possible to determine the cause of vascular compression.

Diagnóstico por angiorresonancia magnética del síndrome del estrecho torácico superior / Diagnosis of thoracic outlet syndrome by angio-MRI

Objetivo. Valorar las secuencias y las maniobras recomendadas para el estudio del síndrome del estrecho torácico superior (SETS) y la utilidad de la resonancia magnética (RM) a la hora de demostrar su etiología. Material y método. Presentamos un estudio de 8 pacientes con clínica sugerente de SETS. En todos ellos se realizó estudio anatómico de RM, angio-RM con gadolinio, con los brazos extendidos a lo largo del cuerpo y con maniobras posturales de abducción y elevación de los brazos, radiografía de tórax y angiografía digital. Se analizaron las características anatómicas del estrecho torácico superior bilateralmente antes y durante las maniobras posturales. Así mismo, se estudió la permeabilidad de los vasos y la integridad del plexo braquial. Resultados. En dos casos se demostró trombosis de la arteria y vena subclavias respectivamente producida por una costilla cervical, confirmada en la radiografía de tórax. En una paciente se demostró estenosis de la arteria subclavia con maniobra de abducción secundaria a hipertrofia del músculo escaleno anterior; la angiografía digital demostró los mismos hallazgos. En dos casos la angio-RM mostró trombosis vascular, arterial en un caso y venosa en otro, sin evidencia de anomalías anatómicas, este hallazgo se confirmó en el estudio de angiografía digital. En dos pacientes la RM, angio-RM y angiografía digital no mostraron hallazgos patológicos. En un caso la RM puso de manifiesto la presencia de una costilla cervical sin repercusión vascular. Conclusión. La angio-RM con gadolinio es útil para valorar el SETS. Es importante evaluar los pacientes en reposo y con maniobras posturales, pudiendo en muchos casos demostrar la causa responsable de la compresión vascular

Objective. To evaluate the sequences and maneuvers recommended for the study of the thoracic outlet syndrome (TOS) and the usefulness of magnetic resonance imaging (MRI) in demonstrating its etiology. Material and methods. We present a study of eight patients with clinical presentation suggestive of TOS. All underwent MRI, gadolinium-enhanced angio-MRI with the arms extended along the body and with postural maneuvers of abduction and elevation of the arms, plain-film chest x-rays, and digital angiography. The anatomic characteristics of the superior aperture of the thorax were analyzed on both sides before and during postural maneuvering. Likewise, the permeability of the vessels and integrity of the brachial plexus was studied. Results. In two cases, angio-MRI demonstrated thrombosis, of the subclavian artery in one case and of the subclavian vein in the other, caused by a cervical rib, which was confirmed at plain-film chest x-ray. In one case, angio-MRI demonstrated stenosis of the subclavian artery on abduction, secondary to hypertrophy of the anterior scalene muscle, and digital angiography showed the same findings. In two cases, angio-MRI showed vascular thrombosis, arterial in one case and venous in the other, without evidence of anatomic anomalies; these findings were confirmed at digital angiography. In two cases, no pathological findings were observed at MRI, angio-MRI, or digital angiography. In one case, MRI showed the presence of a cervical rib without vascular repercussions. Conclusion. Gadolinium-enhanced angio-MRI is useful in the evaluation of TOS. It is important to examine patients at rest and during different postural maneuvers. In many cases it is possible to determine the cause of vascular compression

Lanthanide(III) complexes with a tetrapyridine pendant-armed macrocyclic ligand: 1H NMR structural determination in solution, X-ray diffraction, and density-functional theory calculations.

Complexes between the tetrapyridyl pendant-armed macrocyclic ligand (L) and the trivalent lanthanide ions have been synthesized, and structural studies have been made both in the solid state and in aqueous solution. The crystal structures of the La, Ce, Pr, Gd, Tb, Er, and Tm complexes have been determined by single-crystal X-ray crystallography. In the solid state, all the cation complexes show a 10-coordinated geometry close to a distorted bicapped antiprism, with the pyridine pendants situated alternatively above and below the main plane of the macrocycle. The conformations of the two five-membered chelate rings present in the complexes change along the lanthanide series. The La(III) and Ce(III) complexes show a lambdadelta (or deltalambda) conformation, while the complexes of the heavier lanthanide ions present lambdalambda (or deltadelta) conformation. The cationic [Ln(L)]3+ complexes (Ln = La, Pr, Eu, Tb, and Tm) were also characterized by theoretical calculations at the density-functional theory (DFT) B3LYP level. The theoretical calculations predict a stabilization of the lambdalambda (or deltadelta) conformation on decreasing the ionic radius of the Ln(III) ion, in agreement with the experimental evidence. The solution structures show a good agreement with the calculated ones, as demonstrated by paramagnetic NMR measurements (lanthanide induced shifts and relaxation rate enhancements). The 1H NMR spectra indicate an effective D2 symmetry of the complexes in D2O solution. The 1H lanthanide induced shifts (LIS) observed for the Ce(III), Tm(III), and Yb(III) complexes can be fit to a theoretical model assuming that dipolar contributions are dominant for all protons. The resulting calculated values are consistent with highly rhombic magnetic susceptibility tensors with the magnetic axes being coincident with the symmetry axes of the molecule. In contrast with the solid-state structure, the analysis of the LIS data indicates that the Ce(III) complexes present a lambdalambda (or deltadelta) conformation in solution.

Genetic evidence for two sibling species within Contracaecum ogmorhini Johnston & Mawson, 1941 (Nematoda: Anisakidae) from otariid seals of boreal and austral regions.

Genetic variation of Contracaecum ogmorhini (sensu lato) populations from different otariid seals of the northern and southern hemisphere was studied on the basis of 18 enzyme loci as well as preliminary sequence analysis of the mitochondrial cyt b gene (260 bp). Samples were collected from Zalophus californianus in the boreal region and from Arctocephalus pusillus pusillus, A. pusillus doriferus and A. australis from the austral region. Marked genetic heterogeneity was found between C. ogmorhini (sensu lato) samples from the boreal and austral region, respectively. Two loci (Mdh-2 and NADHdh) showed fixed differences and a further three loci (Iddh, Mdh-1 and 6Pgdh) were highly differentiated between boreal and austral samples. Their average genetic distance was D(Nei) = 0.36 at isozyme level. At mitochondrial DNA level, an average proportion of nucleotide substitution of 3.7% was observed. These findings support the existence of two distinct sibling species, for which the names C. ogmorhini (sensu stricto) and C. margolisi n. sp., respectively, for the austral and boreal taxon, are proposed. A description for C. margolisi n. sp. is provided. No diagnostic morphological characters have so far been detected; on the other hand, two enzyme loci, Mdh-2 and NADHdh, fully diagnostic between the two species, can be used for the routine identification of males, females and larval stages. Mirounga leonina was found to host C. ogmorhini (s.s.) in mixed infections with C. osculatum (s.l.) (of which C. ogmorhini (s.l.) was in the past considered to be a synonym) and C. miroungae; no hybrid genotypes were found, confirming the reproductive isolation of these three anisakid species. The hosts and geographical range so far recorded for C. margolisi n. sp. and C. ogmorhini (s.s.) are given.

X-ray diffraction and (1)H NMR in solution: structural determination of lanthanide complexes of a Py(2)N(6)Ac(4) ligand.

Complexes between the Py(2)N(6)Ac(4) (H(4)L) ligand containing four carboxylate pendant arms and trivalent lanthanide ions have been synthesized, and structural studies have been made both in the solid state and aqueous solution. The crystal structures of the La, Ce, Sm, Tb, Dy, Ho, Er, Tm, and Lu complexes, with chemical formulas [LaH(2)L](NO(3)).3H(2)O (1), [Ce(4)L(2)](NO(3))(4).30H(2)O (2), [SmHL].EtOH.3H(2)O (5), [TbHL].EtOH.3H(2)O (8), [DyHL].2EtOH.2H(2)O (9), [HoHL].3H(2)O (10), [ErHL].EtOH.3H(2)O (11) [TmHL].EtOH.3H(2)O (12), and [LuHL].3H(2)O (14), have been determined by single-crystal X-ray crystallography. In the solid state, the complexes of the lighter lanthanide ions La(3+)-Dy(3+) show a 10-coordinated geometry close to a distorted bicapped antiprism, where the carboxylate pendants are situated alternatively above and below the best plane that contains the nitrogen donor atoms. The complexes of the heavier ions, Ho(3+)-Lu(3+), have a 9-coordinated geometry close to distorted tricapped trigonal prism, with one of the pendant carboxylate groups uncoordinated. The ligand is in a "twist-fold" conformation, where the twisting of the pyridine units is accompanied by an overall folding of the major ring of the macrocycle so that the pyridine nitrogen atoms and the metal are far from linear. The aqueous solution structures of the complexes were thoroughly characterized, the diamagnetic ones (La(3+) and Lu(3+)) by their COSY NMR spectra, and the paramagnetic complexes using a linear least-squares fitting of the (1)H LIS (lanthanide-induced shift) and LIR (lanthanide-induced relaxation) data with rhombic magnetic susceptibility tensors. The solution structures obtained for the La(3+)-Dy(3+) complexes (10-coordinate) and for the Tm(3+)-Lu(3+) complexes (9-coordinate) are in very good agreement with the corresponding crystal structures. However, the 10-coordinate structure is still exclusive in solution for the Ho(3+) complex and predominant for the Er(3+) complex.

Independent adaptation to riverine habitats allowed survival of ancient cetacean lineages.

The four species of "river dolphins" are associated with six separate great river systems on three subcontinents and have been grouped for more than a century into a single taxon based on their similar appearance. However, several morphologists recently questioned the monophyly of that group. By using phylogenetic analyses of nucleotide sequences from three mitochondrial and two nuclear genes, we demonstrate with statistical significance that extant river dolphins are not monophyletic and suggest that they are relict species whose adaptation to riverine habitats incidentally insured their survival against major environmental changes in the marine ecosystem or the emergence of Delphinidae.

Two hydrochlorides of 7-methyl-3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),13,15-triene.

The X-ray structure determinations of the two title compounds, namely 7-methyl-7,17-diaza-3,11-diazoniabicyclo[11.3.1]heptadeca-1(17),13,15-triene dichloride monohydrate, C(14)H(26)N(4)(2+).2Cl(-).H(2)O, (I), and 7-methyl-17-aza-3,7,11-triazoniabicyclo[11.3.1]heptadeca-1(17),13,15-triene 2.826-chloride 0.174-nitrate, C(14)H(27)N(4)(3+).2.826Cl(-).0.174NO(3)(-), (II), are reported. Protonation occurs at the secondary amine N atoms in (I) and at all three amine N atoms in (II) to which the Cl(-) ions are linked via N-H.Cl hydrogen bonds. The macrocyclic hole is quite different in both structures, as is observed by comparing particularly the N3.N4 distances [2.976 (4) and 4.175 (4) A for (I) and (II), respectively]. In (II), a Cl(-) ion alternates with an NO(3)(-) ion in a disordered structure.

Tuberculosis in a wild subantarctic fur seal from Argentina.

The first case of tuberculosis is described in a wild subantarctic fur seal (Arctocephalus tropicalis) found on the Argentine coast. There was hydrothorax and white firm granulomatous lesions of 40-50 mm in diameter in the lungs. Lesions consisted of a central area of caseous necrosis, an intermediate zone of epithelioid and lymphocytic mononuclear cells, and a peripheral zone of connective tissue. Biochemical and drug sensitivity tests and inoculation of Guinea pigs confirmed the identification as Mycobacterium tuberculosis complex. Arctocephalus tropicalis is the fifth pinniped species in which the M. tuberculosis complex has been detected. Since subantarctic fur seals are widely distributed in the Southern Hemisphere, it is possible that the tuberculosis cases may have a common origin and could spread to other austral regions and species.

Molecular characterization of mycobacteria isolated from seals.

Tuberculosis (TB) was diagnosed in 10 seals from three species (Arctocephalus australis, Arctocephalus tropicalis and Otaria flavescens) found in South America. The mycobacteria isolated from these cases belonged to the Mycobacterium tuberculosis complex, as determined by RFLP using an IS6110 probe, spoligotyping, analysis of the 16S rRNA gene sequence and by PCR-restriction analysis of hsp65. Polymorphisms in gyrA, katG, oxyR and pncA were investigated in some of the isolates, as well as the presence of the MPB70 antigen. The insertion sequence IS6110 was present in three to seven copies in the genome of the mycobacteria isolated from seals. Using the IS6110 probe, six patterns (designated A, B, C, D, E and F) were identified from 10 different isolates. Patterns A and B were found for the mycobacteria isolated from two and four seals, respectively, indicating an epidemiological relationship between isolates grouped according to their IS6110 RFLP. The mycobacteria isolated from seals shared the majority of their IS6110 DNA-containing restriction fragments, and nine isolates had an identical spoligotype; only one isolate showed a minor difference in its spoligotype. In addition, none of these spoligotypes were found in other M. tuberculosis complex strains. These results suggest that the isolates from seals constitute a unique group of closely related strains. The mycobacteria isolated from seals showed polymorphisms at gyrA codon 95 and katG codon 463, as do group 1 M. tuberculosis, and M. bovis. Group 1 mycobacteria are associated with cluster cases. The spoligotypes found in the mycobacteria isolated from seals lack spacers 39-43, as does M. bovis, but the MPB70 antigen, which is highly expressed in M. bovis and minimally expressed in M. tuberculosis, was not detected in these mycobacteria. The mycobacteria isolated from seals also showed oxyR and pncA polymorphisms specific to M. tuberculosis. In conclusion, the mycobacteria that cause TB in seals in the South-Western Atlantic are a related group, and based on the combination of genetic characteristics, belong to a unique genotypic group within the M. tuberculosis complex.

Tuberculosis in sea lions and fur seals from the south-western Atlantic coast.

Diverse pathological conditions causing the strandings and/or deaths of several species of sea lions and seals on the northern coast of the province of Buenos Aires are being studied. Tuberculosis was diagnosed in six cases of strandings, involving two otariid seal species (one Otaria flavescens and five Arctocephalus australis), between March 1989 and December 1992. Necropsies were performed on all six cases. Granulomatous lesions were observed in the prescapular and hepatic lymph nodes. Lesions were also seen in the lungs, pleura, liver, spleen and peritoneum. Bacteriological isolation was attempted from all the samples. The isolates were identified as belonging to the Mycobacterium tuberculosis complex. Some showed characteristics consistent with M. bovis, whereas others demonstrated properties of M. tuberculosis. Genomic deoxyribonucleic acid (DNA) from these strains was analysed by restriction fragment length polymorphism (RFLP), using IS6110, a genetic marker found only in the Mycobacterium tuberculosis complex. Using the IS6110 probe, similar fingerprints were obtained, suggesting a common source of infection. However, the pattern of DNA differed from DNA patterns of M. bovis isolated from humans and cattle in Argentina, which generally contain a unique 1.9 kbp band. These results suggest that mycobacteria isolated from wild seals form a different grouping inside the M. tuberculosis complex. This is the first time that tuberculosis has been detected in wild seals from the south-western Atlantic coast.

Environmental contamination and marine mammals in coastal waters from Argentina: an overview.

Environmental contamination become an increasing global problem. Different scientific strategies have been developed in order to assess the impact of pollutants on marine ecosystems. The distribution of toxic contaminants in tissues of different marine mammal species--both cetaceans and pinnipeds--has been studied in many ecosystems, as well as several related ecological processes, like pollutant accumulation or transfer through the food web. A research program directed towards evaluating the occurrence of pollutants in marine mammals from the coastal waters of Argentina (southwestern Atlantic Ocean) has been developed since 1985, and includes the study of heavy metal contents in stranded or incidentally caught animals. The marine mammal species studied during this period were: the seals Otaria flavescens and Arctocephalus australis, and small cetaceans Tursiops gephyreus, Pontoporia blainvillei, Kogia breviceps and Ziphius cavirostris. In most of the cases, high contents of heavy metals (total mercury, cadmium, zinc, and copper) have been recorded. Moreover, liver showed the maximum capability for accumulation of heavy metals in all studied species. The biological and ecological characteristics of each species of the above-mentioned marine mammals (feeding habits, age, migratory pathways, or sex) contributed to the understanding of the metal sources. Considering the results as obtained during the study period it can be assumed that: (1) The global distribution of toxic contaminants also affects the southwestern Atlantic Ocean ecosystems, and (2) Marine mammals could be appropriate bioindicator species in order to assess this kind of environmental problem.

El injerto venoso autógeno. Su valor en el tratamiento de las oclusiones vasculares

Se expone la experiencia en 17 casos de defectos arteriales tratados por injerto venoso autógeno. Se presentan los resultados y discuten las conclusiones a que éstos han llevado (AU)