Thoracic aortic aneurysm repair using the elephant trunk technique and associated complications.

The frozen elephant trunk stent has greatly facilitated the repair of elective and emergency arch and proximal descending thoracic aortic aneurysms and dissections. As one of the few tertiary hospitals that routinely inserts and images the floating and frozen elephant trunk grafts, we aim to provide an up-to-date illustration of the contrasting methods of elephant trunk thoracic aortic aneurysm repair through a computed tomography (CT) review and detail the common radiological interpretation pitfalls in addition to the most significant associated complications.

CT of transposition of the great arteries in adults.

Transposition of the great arteries is one of the most common cyanotic congenital heart diseases. It is characterised by an abnormal connection of the ventricles and great arteries, so that the aorta arises from the morphological right ventricle and the pulmonary artery arises from the morphological left ventricle. Historically, as with many congenital heart diseases, patients with transposition of the great arteries had poor life expectancy. Advances in surgical and medical management have resulted in patients surviving into adulthood. As these patients are living longer, they will be encountered more frequently in practice. The purpose of this article is to familiarise the general radiologist with the expected postoperative anatomy, and the appearance on cross-sectional imaging as well as the long-term complications in this group of patients.

Cross-sectional imaging of the Fontan circuit in adult congenital heart disease.

The Fontan circuit is the result of a palliative surgical procedure that is performed in patients with a functionally single ventricle cardiac anomaly. The success of this operation has resulted in an increasing population of adults with this anatomy and physiology. The purpose of this article is to familiarize the general radiologist with the expected anatomy and cross-sectional imaging findings, highlight special imaging considerations, and examine the common complications that are encountered in this group of patients.

Update on imaging of non-infectious musculoskeletal complications of HIV infection.

Acquired immunodeficiency syndrome (AIDS) results from infection with human immunodeficiency virus (HIV), producing an immunodeficient state and severe pathology across multiple organ systems. Musculoskeletal involvement is particularly prevalent in this population with both infectious and non-infectious complications encountered, but it is suggested that the latter will affect 72% of HIV-infected individuals. In this review we aim to provide an update on the imaging characteristics of the non-infectious manifestations. The conditions include HIV-related arthritis as well as various malignancies, myositis, anaemia, osteonecrosis, rhabdomyolysis, hypertrophic osteoarthropathy and therapy-related side effects. For the clinician, the diagnostic challenge lies in differentiating disease-related symptoms from therapy-related side effects, particularly when clinical and laboratory features can be non-specific. This is especially difficult following the widespread introduction of highly active anti-retroviral therapy (HAART). Imaging investigations and MRI in particular have proven vital for facilitating early diagnosis and enabling prompt treatment. Furthermore, wider availability of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) has allowed whole-body assessment for staging and treatment response of malignancy. Understanding the pathogenesis of the various conditions and recognising their imaging features is essential for the clinical radiologist.

Molecular cloning and characterization of the structural gene for the major iron-regulated protein expressed by Neisseria gonorrhoeae.

This report describes the cloning and sequencing of the major iron-regulated protein (termed Fbp) of Neisseria gonorrhoeae strain F62. Attempts to identify recombinants expressing the Fbp using specific antibody proved unsuccessful. Therefore, an alternative cloning strategy using oligonucleotide probes derived from NH2-terminal and tryptic fragments of this protein was used to identify short fragments of the gene. Using this methodology, the gene encoding the precursor of Fbp was cloned on three separate overlapping fragments and sequenced, and the amino acid sequence was deduced. These data were unambiguously confirmed by the known NH2-terminal amino acid sequence and were supported by the sequences from tryptic fragments that lie outside of this region. Using oligonucleotide probes, we were unable to obtain clones encoding the potential regulatory region of this protein. Therefore, the technique of inverse polymerase chain reaction was used to amplify a fragment containing an additional 200 bp. This fragment was cloned and sequenced and found to contain a consensus ribosome binding site and potential -10 and -35 sequences. Hybridization analysis of genomic DNA from gonococcal strain F62 indicated that only a single copy of the Fbp gene exists per genome. These results complement the biochemical characterization of the Fbp expressed by gonococci and further suggest that it has a role in iron-acquisition.

Altered neuropeptide Y concentrations in specific hypothalamic regions of obese (fa/fa) Zucker rats. Possible relationship to obesity and neuroendocrine disturbances.

Neuropeptide Y (NPY) concentrations were measured by radioimmunoassay in eight microdissected hypothalamic regions of obese (fa/fa) and lean (Fa/?) Zucker rats. Freely fed obese rats showed significant (40-100%) increases in NPY concentrations in several regions, notably the paraventricular, ventromedial, and dorsomedial nuclei and the arcuate nucleus/median eminence, compared with lean rats. Hypothalamic NPY concentrations were not affected in either obese or lean rats by food restriction, which caused 25% weight loss over 3 wk. Refeeding to initial weight significantly increased NPY levels in the ventromedial and dorsomedial nuclei in lean rats but did not significantly alter NPY concentrations in any hypothalamic region in obese rats. These observations indicate fundamental differences in the regulation of hypothalamic NPY between obese and lean Zucker rats. NPY injected into the paraventricular nucleus and other regions causes hyperphagia, obesity, and increased secretion of insulin, glucagon, ACTH, and corticosterone. These behavioral and neuroendocrine abnormalities all occur in the obese Zucker syndrome and may be due to increased NPY-ergic activity in the hypothalamus.

Case report: MR imaging features of endometriosis at the umbilicus.

The radiological features of extrapelvic endometriosis at the umbilicus with large ovarian endometriomas are described. In this patient, the umbilical lesion appears as hypointense on T(1) weighted and T(2) weighted MR images. The MR characteristics of endometriosis at the umbilicus are compared with those found within the pelvis.

Peripheral limb vascular malformations: an update of appropriate imaging and treatment options of a challenging condition.

Peripheral vascular malformations encompass a wide spectrum of lesions that can present as an incidental finding or produce potentially life- or limb-threatening complications. They can have intra-articular and intraosseous extensions that will result in more diverse symptomology and present greater therapeutic challenges. Developments in classification, imaging and interventional techniques have helped to improve outcome. The onus is now placed on appropriate detailed preliminary imaging, diagnosis and classification to direct management and exclude other more common mimics. Radiologists are thus playing an increasingly important role in the multidisciplinary teams charged with the care of these patients. By fully understanding the imaging characteristics and image-guided procedures available, radiologists will be armed with the tools to meet these responsibilities. This review highlights the recent advances made in imaging and the options available in interventional therapy.

ICI D7114: a novel selective adrenoceptor agonist of brown fat and thermogenesis.

Increasing energy expenditure by treatment with thermogenic drugs is not new, but available drugs have suffered from the problem of lack of selectivity. In the last decade two key findings have allowed the development of selective thermogenic drugs that have promise in the treatment of obesity. 1) The recognition that brown adipose tissue (BAT) plays a role in compensatory increases in energy expenditure has allowed an approach directed at a target organ. 2) The demonstration showing that increases in the activity of BAT may be modulated by an atypical (beta 3) adrenoceptor has led to the development of a new peripherally acting beta-adrenoceptor agonist ICI D7114, which stimulates thermogenesis at doses that have little effect on beta 1 or beta 2 adrenoceptors. Treatment with the compound activates BAT and thermogenesis even in species and situations where the intrinsic capacity is low. 3) The compound has beneficial effects in animal models of obesity and disturbed glucose and lipid homeostasis.

Quantitation of RT-PCR amplified cytokine mRNA by aequorin-based bioluminescence immunoassay.

We described here a bioluminescence-based immunoassay for the quantitation of RT-PCR amplified cytokine mRNA. This technique uses a standard RT-PCR procedure, with the following modifications. The forward primer in the PCR reaction is labeled with a 5' biotin molecule. Following PCR, a digoxigenin-conjugated oligonucleotide probe is hybridized to the target biotin-labeled DNA template. The hybridized duplex is captured onto a streptavidin-coated microtiter plate. The bound product is quantitated by adding digoxigenin-specific antibodies conjugated with the photoprotein aequorin. The amount of specific DNA captured onto the plate is quantitated by triggering the bioluminescence reaction through the addition of calcium ions. This technique detected as low as 40 amol of amplified cytokine products, or 500 copies of templates when 27 PCR cycles were used. The high sensitivity of this technique enables the quantitation of target DNA during the exponential phase of the PCR reaction. The aequorin-bioluminescence assay is an alterative non-radioactive method for the quantitation of PCR products.

Selective beta 3-adrenergic agonists of brown adipose tissue and thermogenesis. 1. [4-[2-[(2-Hydroxy-3-phenoxypropyl)amino]ethoxy]phenoxy]acetates.

The ester methyl [4-[2-[(2-hydroxy-3-phenoxypropyl)amino]ethoxy]phenoxy]acetate (8) has been identified as the most interesting member of a series of selective beta 3-adrenergic agonists of brown adipose tissue and thermogenesis in the rat. In vivo it acts mainly via the related acid 10. Potency was generally markedly reduced by placing substituents on the phenyl ring of the phenoxypropanolamine unit of 8; only the 2-fluoro analogue 16 had comparable potency to 8. Other structure-activity relationships are discussed. Further testing of 8 (ICI 198157) has shown that in the rat it stimulates the beta 3-adrenergic receptor in brown adipose tissue at doses lower than those at which it affects beta 1 and beta 2 adrenergic receptors in other tissues. It increases metabolic rate, as judged by an increase in oxygen consumption, and in the genetically obese Zucker rat it causes a reduced rate of weight gain. This class of compound may be useful in the treatment of obesity in man.

Selective beta 3-adrenergic agonists of brown adipose tissue and thermogenesis. 2. [4-[2-[(2-Hydroxy-3-phenoxypropyl)amino]ethoxy]phenoxy]acetamides.

The ester methyl [4-[2-[(2-hydroxy-3-phenoxypropyl)amino]ethoxy]phenoxy]acetate (1) (R1 = OMe) had previously been identified as the most interesting member of a series of selective beta 3-adrenergic agonists of brown adipose tissue and thermogenesis in the rat. In vivo it acts mainly via the related acid 1 (R1 = OH). Amides have been examined to determine whether they have advantages over the ester. In particular, in the rat and dog the half-lives of amides of appropriate potency were no longer than those of the ester. The amide (S)-4-[2-[(2-hydroxy-3-phenoxypropyl)amino]ethoxy]-N-(2- methoxyethyl)phenoxyacetamide [S-27, ICI D7114] was selected as having properties consistent with a sustained-release formulation should that prove necessary. Unlike the ester it is resistant to hydrolysis in the gut lumen. Further testing of ICI D7114 has shown that in the rat, cat, and dog it stimulates the beta 3-adrenergic receptor in brown adipose tissue at doses lower than those at which it affects beta 1- and beta 2-adrenergic receptors in other tissues. Slimming effects were observed in the dog. ICI D7114 may be a selective thermogenic agent in man and may be useful in the treatment of obesity and diabetes.

Prediction of the usefulness of combined mammography and scintimammography in suspected primary breast cancer using ROC curves.

UNLABELLED: The aim of this study was to compare the accuracy of 99mTc-methoxyisobutylisonitrile scintimammography (SMM) and conventional mammography in patients presenting with suspected primary breast cancer. Receiver-operating-characteristic (ROC) curve analysis was applied to determine if a combination of x-ray mammography (XMM) and SMM was more accurate than a single test alone. METHODS: The results of SMM, XMM, and a combination of both studies performed over a 3-y period on 374 suspicious lesions in 353 patients with no previous history of breast cancer were reviewed. Each scan report was reviewed and graded as follows: grade 1, definitely normal or benign; grade 2, probably normal or benign; grade 3, equivocal; grade 4, probably cancer; and grade 5, definitely cancer. The results were verified by pathologic examination of biopsy material obtained from each suspicious mass. ROC curves were generated from these results. RESULTS: There were 204 malignant breast tumors and 170 nonmalignant breast lesions. SMM diagnosed correctly 181 breast cancers and was true-negative in 122 benign breast lesions: sensitivity, 89%; specificity, 71%; positive predictive value (PPV), 79%; and negative predictive value (NPV), 84%. XMM diagnosed correctly 143 malignant tumors and was true-negative in 117 nonmalignant lesions. The sensitivity, specificity, PPV, and NPV for XMM were 70%, 69%, 73%, and 66%, respectively. Using a combination of the two tests, the combined sensitivity was 93%, specificity was 72%, PPV was 80%, and NPV was 90%. Using the index of the area under the ROC curve obtained by the rating method showed that the combination of XMM and SMM was significantly more accurate than either of the individual tests if performed alone (P < 0.05). CONCLUSION: This study shows that the combination of XMM and SMM produces more accurate results than either modality alone. Therefore, if there is doubt about the accuracy of XMM, SMM should be used as the second-line test in breast imaging.

Sequence analysis of the Ebola virus genome: organization, genetic elements, and comparison with the genome of Marburg virus.

Sequence analysis of the second through the sixth genes of the Ebola virus (EBO) genome indicates that it is organized similarly to rhabdoviruses and paramyxoviruses and is virtually the same as Marburg virus (MBG). In vitro translation experiments and predicted amino acid sequence comparisons showed that the order of the EBO genes is: 3'-NP-VP35-VP40-GP-VP30-VP24-L. The transcriptional start and stop (polyadenylation) signals are conserved and all contain the sequence 3'-UAAUU. Three base intergenic sequences are present between the NP and VP35 genes (3'-GAU) and VP40 and GP genes (3'-AGC), and a large intergenic sequence of 142 bases separates the VP30 and VP24 genes. Novel gene overlaps were found between the VP35 and VP40, the GP and VP30, and the VP24 and L genes. Overlaps are 20 or 18 bases in length and are limited to the conserved sequences determined for the transcriptional signals. Stem-and-loop structures were identified in the putative (+) leader RNA and at the 5' end of each mRNA. Hybridization studies showed that a small second mRNA is transcribed from the glycoprotein gene, and is produced by termination of transcription at an atypical polyadenylation signal located in the middle of the coding region. The predicted amino acid sequence of the glycoprotein contains an N-terminal signal peptide sequence, a hydrophobic anchor sequence, and 17 potential N-linked glycosylation sites. Alignment of predicted amino acid sequences showed that the structural proteins of EBO and MBG contain large regions of homology despite the absence of serologic cross-reactivity.

Detection and identification of vaccine-related polioviruses by the polymerase chain reaction.

We have used the polymerase chain reaction (PCR) to obtain sensitive detection and identification of poliovirus RNA genomes. Primer pairs were designed to permit identification of each Sabin poliovaccine strain by the electrophoretic mobilities of the amplified DNA products (Sabin 1: 97 bp; Sabin 2: 71 bp; Sabin 3: 44 bp). The compositions of samples containing mixtures of vaccine strains could be readily determined by PCR. When the amplified products were visualized by ethidium bromide fluorescence, as few as 250 genomic copies in the original sample could be detected. When PCR was used in combination with strain-specific 32P-labeled oligonucleotide probes, the limit of detection was less than or equal to 2.5 poliovirus genomes, exceeding the sensitivity of poliovirus isolation in cell culture by at least 100-fold. PCR amplifications may be performed on virion RNAs extracted directly from clinical specimens, potentially eliminating the requirement for virus isolation in routine identifications while yielding reliable results within 8 h.

Genotype-specific in vitro amplification of sequences of the wild type 3 polioviruses from Mexico and Guatemala.

The extensive nucleotide sequence heterogeneity among independent genotypes of wild polioviruses permits the systematic design of genotype-specific molecular reagents. We have prepared two sets of polymerase chain reaction (PCR) primer pairs specific for the genotype of wild poliovirus type 3 recently endemic to Mexico and Guatemala. Nucleotide sequences of a representative wild type 3 virus isolated in Mexico in 1989 differed from the corresponding Sabin 3 (Leon 12 a1b) sequences at 167 of 900 positions within the VP1 region. From the sequence data, wild virus-specific primer pairs were designed to complement regions of high mismatch (greater than 33%) with Sabin 3 templates. Primer binding sites were spaced along the genome so that the predicted amplification products (142 bp and 163 bp) could be easily resolved electrophoretically from the products generated with our Sabin strain-specific primers (Sabin 1: 97 bp; Sabin 2: 71 bp; Sabin 3: 53 bp). RNAs of all wild type 3 poliovirus isolates from Mexico and Guatemala obtained over a 13-year period (1977-1990) served as efficient templates for amplification of the 142-bp and 163-bp products. Genomic templates derived from vaccine-related polioviruses and most heterologous wild polioviruses were inactive under equivalent reaction conditions. Amplifications generating a 114-bp product with a broadly reacting primer pair, matching highly conserved sequences in the 5'-noncoding region, provided a positive control for the presence in samples of poliovirus (or enterovirus) RNAs. Selective amplification of wild Mexico-Guatemala type 3 poliovirus sequences was obtained with either primer set in reactions containing large stoichiometric excesses (up to 10(6)-fold) of vaccine-related RNAs. We have used wild genotype-specific PCR primer sets to facilitate identification of wild polioviruses present in both clinical and environmental samples.

Evaluation of ICI D7114, a putative stimulant of brown adipocytes, on histamine-contracted guinea-pig ileum.

1. Experiments were performed to characterize the effects of the novel brown adipocyte stimulant, ICI D7114, in the guinea-pig isolated ileum, right atrium and tracheal chain. In the ileum, agonist-induced inhibition of the contractile response to either histamine or prostaglandin E2 (PGE2) was assessed, along with effects on resting rate in the atrium and resting tone in the tracheal chain. In the latter two preparations, antagonism of isoprenaline-induced responses by ICI D7114 was also assessed. 2. Inhibitory responses were obtained in the ileum to ICI D7114, isoprenaline, BRL37344, and noradrenaline. The responses to ICI D7114, isoprenaline and BRL37344 were resistant to blockade with propranolol (5 microM), naloxone (1 microM), methysergide (0.1 microM), cimetidine, indomethacin and 8-phenyltheophylline (all 10 microM). These responses to isoprenaline, in the presence of propranolol (5 microM), were competitively antagonized by alprenolol (1-100 microM) with a pA2 value of 6.44. The responses to ICI D7114 and BRL37344 were antagonized by single concentrations of alprenolol (1 microM) with apparent pKB values of 6.53 and 6.57 respectively. These data indicate an effect of ICI D7114 at the atypical beta-adrenoceptor in the guinea-pig ileum. 3. The order and relative potency of agonists at the atypical beta-adrenoceptor was BRL37344 (4) < isoprenaline (1) = ICI D7114 (1.1) > noradrenaline (0.5). 4. ICI D7114 (1 nM - 10 microM) caused no significant change in the rate of beating or the resting tone of the guinea-pig right atrium or tracheal chain respectively. It did, however, cause selective blockade of the responses to isoprenaline in these tissues (apparent pKB values 7.63 and 5.85 in atrium and tracheal chain respectively). Responses to histamine (atrium) and aminophylline (tracheal chain) were not significantly affected by 10 microM ICI D7114.5. These results demonstrate that ICI D7114 possesses selective agonist activity at atypical beta-adrenoceptors in the guinea-pig ileum and its use as a tool may help to establish a role for the atypical beta-adrenoceptor in the control of gastrointestinal motility.

Zeneca ZD7114 acts as an antagonist at beta 3-adrenoceptors in rat isolated ileum.

1. The relaxant effects of Zeneca ZD7114, BRL37344 (putative beta 3-adrenoceptor agonists) and various phenylethylamine-based agonists were studied in isolated ileum of the rat where tone was increased with carbachol (0.5 microM). Agonist-induced relaxation.was measured under equilibrium conditions with alpha-, beta 1- and beta 2-adrenoceptors inhibited. 2. Relaxant responses were obtained to isoprenaline, noradrenaline, and BRL37344, although, the efficacy of this latter agent was significantly.lower than that of isoprenaline. Salbutamol caused weak relaxation (< 20%) at high concentrations (10 microM) and ZD7114 was without significant relaxant effect even at high concentrations (10 microM). 3. Relaxant responses to isoprenaline and BRL37344 were weakly antagonized by high concentrations of (+/-)-propranolol (10 and 100 microM) yielding pKB values of 5.7 with isoprenaline as the agonist and 5.5 with BRL37344 as the agonist. 4. The non-selective beta-adrenoceptor antagonist, (+/-)-alprenolol (1-100 microM) caused competitive antagonism of the relaxant responses to isoprenaline (pA2 value = 6.5). A similar pKB value was obtained when BRL37344 was used as the agonist (6.4). 5. Relaxant effects of isoprenaline and BRL37344 were also antagonized by ZD7114 (1-100 microM) yielding pA2 and pKB values of 6.3 and 6.7 respectively. 6. The low potencies of (+/-)-propranolol and (+/-)-alprenolol as antagonists of the relaxant responses to isoprenaline and BRL37344 indicate that both the agonists and antagonists employed in the current study may interact with beta 3-adrenoceptors in the rat isolated ileum. Contrary to the previous findings in guinea-pig ileum, where BRL37344 and ZD7114 were full agonists, in the current study, BRL37344 was a partial agonist and ZD7114 an antagonist at the beta 3-adrenoceptor in rat ileum.

ICI D7114 a novel selective beta-adrenoceptor agonist selectively stimulates brown fat and increases whole-body oxygen consumption.

1. ICI D7114 is a novel, beta-adrenoceptor agonist which stimulates whole body oxygen consumption in conscious rats, cats and dogs and brown adipose tissue (BAT) activity in conscious rats. Treatment of rats with ICI D7114 stimulated oxygen consumption (ED50, 0.04 mg kg-1, p.o.) and BAT mitochondrial guanosine diphosphate (GDP)-binding (ED50, 0.15 mg kg-1, p.o.) with no chronotropic effects on the heart at these doses. 2. Reference beta-adrenoceptor agonists, isoprenaline and clenbuterol, also stimulated oxygen consumption and BAT activity but were less selective because they also produced effects on heart rate at these doses. 3. Treatment of conscious rats with ICI D7114 did not attenuate the chronotropic effects on the heart of a subsequent isoprenaline challenge. 4. Administration of ICI D7114 or of its acid metabolite had no effect in a cat soleus muscle model of tremor or on blood potassium levels in the conscious dog, indicating lack of effects at beta 2-adrenoceptors. 5. The results indicate that ICI D7114 may have activity at atypical beta-adrenoceptors in brown adipose tissue leading to increased whole body oxygen consumption.