Ultrasonography-guided radial artery catheterization is superior compared with the traditional palpation technique: a prospective, randomized, blinded, crossover study.

BACKGROUND: Radial artery catheterization is gaining popularity for diagnostic and interventional procedures. Palpation technique is widely used for the procedure, but ultrasonography has been shown to increase catheterization success. A recently described ultrasonography technique is termed 'dynamic needle tip positioning'. We aimed to compare the traditional palpation technique and dynamic needle tip positioning technique in regard to clinically relevant end points. METHODS: The study was conducted as a randomized, patient-blinded, crossover study. Patients underwent bilateral radial artery catheterization using both techniques. The primary end point of the study was needle manipulation time. Additional end points were (1) the number of skin perforations, (2) the number of attempts targeting the vessel, (3) the number of catheters placed in first attempt and (4) the number of catheters used. RESULTS: Forty patients were analyzed. There was no significant difference in median needle manipulation time [32 s (range 11-96 s) vs. 39 s (range 9-575 s), P = 0.525], although the variance was lower in the dynamic needle tip positioning group (P < 0.001). In the traditional palpation technique group, a higher number of skin perforations (57 vs. 40, P = 0.003), catheters (46 vs. 40, P = 0.025) and attempts targeting the vessel (104 vs. 43, P < 0.001) were necessary compared with the ultrasonography dynamic needle tip positioning group. First attempt success rate was significantly higher in the ultrasonography dynamic needle tip positioning group (23/40 vs. 38/40, P < 0.001). CONCLUSION: Ultrasonography guidance using the dynamic needle tip positioning technique for radial artery catheterization significantly improves clinically relevant aspects of the procedure.

The genome sequence of the lactic acid bacterium, Carnobacterium maltaromaticum ATCC 35586 encodes potential virulence factors.

The genus Carnobacterium belongs to the lactic acid bacteria and Carnobacterium maltaromaticum is commonly found in modified atmosphere packed and vacuum packed fish and meat products as well as in live fish. This species has been described as a fish pathogenic organism but human clinical isolates have only been obtained at one occasion. To investigate the virulence potential we sequenced the entire genome of strain ATCC 35586, isolated from a diseased salmon. When comparing the translated gene products of ATCC 35586 to those of Gram positive bacterial pathogens and probiotics as well as the related Carnobacterium sp. AT7 we identified a range of putative virulence genes including genes encoding products involved in adhesion to fibronectin and collagen, capsule synthesis, cell wall modification, iron scavenging mechanisms, haemolysis, invasion and resistance to toxic compounds. Of particular interest was the presence of internalin encoding gene homologues to some of those found in Listeria spp. and Lactobacillus plantarum. Furthermore, the ATCC 35586 strain possesses a gene encoding a product similar to the central Listeria monocytogenes transcriptional regulator PrfA, that in this organism controls virulence gene expression by binding to conserved DNA binding sites. Based on the consensus DNA sequence of this binding site, we identified a total of 65 genes in the ATCC 35586 genome that in the upstream region carry a PrfA binding motif. Among these is one of the internalin encoding genes; two genes encoding products involved in capsule biosynthesis as well as various genes encoding products with metabolic functions. In contrast to L. monocytogenes, the ATCC 35586 strain did not encode other PrfA dependent virulence factors such as listeriolysin O, phospholipases A and B, ActA, listeriolysin O, zinc metallo protease and internalins A and B. In conclusion, C. maltaromaticum ATCC 35586 carries putative virulence genes that may explain its reported ability to infect fish. The findings of this study give no reason for concern regarding human health by the presence of this species in food products.

First Report of Bacterial Spot of Peony Caused by a Xanthomonas sp. in the United States.

In early May 2008 and 2009, peony samples (Paeonia spp.) with symptoms of leaf spot and blight were submitted to the Virginia Tech Plant Disease Clinic. The 2008 peony was an unknown cultivar from a northern Virginia landscape. The three cultivars (Dr. Alexander Fleming, Felix Crousse, and Karl Rosenfield) submitted in 2009 were from a commercial nursery in southwestern Virginia that was reporting leaf spot progressing to severe blight, which rendered plants unsalable, on 75% of a 1,219 m2 block during a 10-day period of heavy rainfall. Bacterial streaming from spots was observed. On the basis of phenotypic and biochemical tests, the isolates were determined to be xanthomonads. Two isolates (one recovered from the 2008 sample and one from the 2009 sample) were used in the following work. Isolates were characterized by multilocus sequencing (MLST) (4). PCR reactions were prepared and cycled using 2X ImmoMix (Bioline, Tauton, MA) according to manufacturer's recommendations with an annealing temperature of 58°C. Template DNA was added by touching a single colony with a 20-µl pipette tip and placing the tip into the reaction mix for 1 min. Four bands of the expected size were visualized on an electrophoresis gel and cleaned products were sequenced in forward and reverse directions at the University of Chicago, Cancer Research Center DNA Sequencing Facility. Corresponding gene fragments of each isolate were identical. A consensus sequence (PAMDB Isolate ID No. 936) for each of the four gene fragments was constructed and compared with sequences in NCBI ( http://www.ncbi.nlm.nih.gov/nuccore/ ) and PAMDB ( http://genome.ppws.vt.edu/cgi-bin/MLST/home.pl ) (1) databases using Blastn (2). No perfect match was found. Genetic distances between the peony isolates and all strains in PAMDB were determined by MegAlign (Lasergene; DNAStar, Madison, WI). The Xanthomonas strain most similar to the isolates recovered from the peony samples was Xanthomonas hortorum pv. hederae ICMP 1661 with a genetic distance of 0.023; this strongly suggests that the peony isolates belong to X. hortorum. For Koch's postulates, six surface-disinfested young leaflets from Paeonia lactiflora 'Karl Rosenfield' were inoculated by forcefully spraying a phosphate-buffered saline suspension of each bacterial isolate (~4.3 × 109 CFU/ml) into the underside of the leaf until leaf tissue appeared water soaked. Controls were inoculated similarly with phosphate-buffered saline solution. Moist chambers with inoculated leaves were incubated at ambient temperature under two 48W fluorescent grow lights with 12 h of light and dark. Circular spots were observed on leaves inoculated with the 2009 and 2008 isolates in 18 and 20 days, respectively. No symptoms were observed on controls. Bacterial streaming from leaf spots was observed by phase-contrast microscopy; bacteria were isolated and confirmed to be identical to the original isolates by the methods described above. To our knowledge, this is the first report of a Xanthomonas sp. causing leaf spot and blight on peony. Although bacterial blight of peony has been attributed to a xanthomonad in recent years, the pathogen had not been further characterized (3). References: (1) N. F. Almeida et al. Phytopathology 100:208, 2010. (2) D. J. Altschul et al. J. Mol. Biol. 215:403, 1990. (3) M. L. Gleason et al. Diseases of Herbaceous Perennials. The American Phytopathological Society, St. Paul, MN. 2009. (4) J. M. Young et al. Syst. Appl. Microbiol. 31:366, 2008.

First Report of Downy Mildew of Lima Bean Caused by Phytophthora phaseoli in Virginia.

Delaware, the eastern shore of Maryland, and southern New Jersey have been the center of lima bean (Phaseolus lunatus L.) production in the eastern United States for nearly 50 years (1). Downy mildew has been the most important disease of lima bean in the humid eastern United States over that period. The causal agent of downy mildew, the oomycete pathogen Phytophthora phaseoli Thaxt., was first identified on lima bean in Connecticut in 1887 by Thaxter. Signs and symptoms of lima bean downy mildew include infection, necrosis and abscission of flowers, and shepherd's crooking of racemes, shoot tips, and petioles (1). Sporangia develop on shoot tips, petioles, pins (small pods), and pods in the field and on hypocotyls in-vitro. Since 2005, approximately 50% of the baby lima beans processed in the United States have been grown in Delaware and the eastern shore of Maryland. In 2008, commercial lima bean production began on the eastern shore of Virginia in Accomack County but no downy mildew was reported in that season. In 2009, approximately 1,825 ha in Accomack and Northampton counties were planted to baby lima bean. Weather conditions in 2009, including above average rainfall, were conducive for the development of downy mildew on the Delmarva Peninsula. Downy mildew was widespread in growers' fields in August and September in butter bean in southern New Jersey and baby lima bean in Sussex County, DE. In August 2009, a home gardener in Rappahannock, VA sent samples of infected lima bean pods from baby, Fordhook, and pole lima bean plants to the Virginia Tech Plant Disease Clinic in Blacksburg. On the basis of morphometric analysis, samples were determined microscopically to be infected by a Phytophthora sp. with rather uniform sporangia averaging 39 × 22 µm and short pedicels, diagnostic for P. phaseoli (1). On October 27, 2009, field scouts in Accomack County, VA identified two lima bean fields planted to cv. C-Elite-Select exhibiting moderate symptoms of downy mildew. Samples were brought to the Plant Diagnostic Clinic at the University of Delaware under USDA-APHIS permit and determined to be P. phaseoli based on morphometric analysis. Samples were inoculated onto a lima bean cultivar differential to determine pathogenicity to complete Koch's postulates and to determine their physiological race. Samples were inoculated onto lima bean cvs. 184-185 and C-Elite-Select, which are susceptible to race F and resistant to race E, Eastland and 8-78, which are susceptible to race E and resistant to race F, and Concentrated Fordhook, susceptible to all known races (1). Three pots containing five emerging seedlings each were inoculated with sporangia (approximately 103 per ml) prepared by soaking infected pods in 500 ml of sterile distilled water for 1 min with gentle agitation. Plants were placed in a Percival dew chamber with intermittent misting and set at 19. Infection and disease development were assessed daily and signs developed 7 days postinoculation in cvs. 184-85, C-Elite-Select, and Concentrated Fordhook, but not in Eastland and 8-78. Cultivar differential tests indicated that the isolates were P. phaseoli race F. Hypocotyls of infected plants were scraped, and isolations made on lima bean pod agar confirmed the presence of P. phaseoli. To our knowledge, this is the first time that downy mildew of lima bean has been reported in Virginia. Reference: (1) T.A. Evans et al. Plant Dis. 91:128, 2007.

Duplex ultrasound scanning of peripheral arterial disease of the lower limb.

OBJECTIVES: To assess the reliability and applicability of duplex ultrasound scanning (DUS) of lower limb arteries, compared with digital subtraction angiography (DSA), in patients with peripheral arterial disease (PAD). DESIGN: A prospective, blinded, comparative study. MATERIALS AND METHODS: A total of 169 patients were examined by DUS and DSA. Intermittent claudication (IC) was present in 42 (25%) patients and critical limb ischaemia (CLI) in 127 (75%) patients. To allow segment-to-segment comparison, the arterial tree was divided into 15 segments. In total, 2535 segments were examined using kappa (κ) statistics to test the agreement. RESULTS: The agreement between DUS and DSA was very good (κ>0.8) or good (0.8 ≥ κ>0.6) in most segments, but moderate (0.6 ≥ κ>0.4) in the tibio-peroneal trunk and the peroneal artery. Agreement between the two techniques was significantly better in the supragenicular (κ=0.75 (95% confidence interval (CI): 0.70-0.80)) than in the infragenicular segments (κ=0.63 (0.59-0.67)) (p<0.001). Similarly, the technical success rate was significantly higher in the supragenicular segments (DUS: 100%; DSA: 99%) than in the infragenicular segments (both 93%) (p<0.001). DUS was the best technique for imaging of the distal crural arteries (92% vs. 97%; p<0.001) and DSA was the best technique for imaging of the proximal crural arteries (95% vs. 91%; p<0.01). Neither the agreement nor the technical success rate was influenced by the severity of PAD, that is, IC versus CLI. CONCLUSION: The agreement between DUS and DSA was generally good, irrespective of the severity of ischaemia. DUS performed better in the supragenicular arteries than in the infragenicular arteries. However, DUS compared favourably with DSA in both tibial vessels, particularly in the distal part, which makes DUS a useful non-invasive alternative to DSA.

Stuck long-term indwelling central venous catheters in adolescents: three cases and a short topical review.

We present three cases of fixated vascular injection ports. Two patients had cystic fibrosis and one had an immunological defect. All catheters were made from polyurethane and implanted in adolescent patients. Indwelling time were 6-8 years. One patient's catheter was entirely integrated in the vessel wall and impossible to remove. In the other two cases, catheters were removed with great difficulty by the interventional radiologists. These cases raise important questions concerning the maximum indwelling time and the choice of catheter material when implanting permanent central venous catheters (CVCs) in adolescents. Furthermore, it highlights the importance of not breaking a CVC in the attempt to remove it.

Medication reconciliation in ambulatory care: attempts at improvement.

OBJECTIVE: To enhance overall accuracy of medication lists by providing performance feedback and training to the healthcare team and increasing patient participation in the medication reconciliation process. METHODS: This prospective study involved patients seen in four academic, ambulatory primary care internal medicine clinics. Before the interventions, baseline data were analysed, assessing completeness, correctness and accuracy of medication documentation in the electronic medical record. Interventions to provide performance feedback and training to the healthcare team, increase patient awareness and participation in the medication reconciliation process were implemented. Immediately after each intervention, a data collection was undertaken to assess the effectiveness of the intervention on the accuracy of individual medications and medication lists. RESULTS: Completeness of medication lists improved from 20.4% to 50.4% (p<0.001). The incomplete documentation of medication lists was mostly because of lack of frequency (15.4%) and route (8.9%) for individual medications within a medication list. Correctness of medication lists improved from 23.1% to 37.7% (p = 0.087). The incorrectness in a medication list was mostly because of incorrect medications dose. Patient participation in the medication reconciliation process increased from 13.9% to 33% (p<0.001). The medication list accuracy improved from 11.5% to 29% (p = 0.014). CONCLUSION: In this setting, it was helpful to engage the active participation of all members of the healthcare team and most importantly the patient to improve the accuracy of medication lists.

First Report of Freesia sneak virus in Freesia sp. in Virginia.

In the spring of 2008, freesia, cvs. Honeymoon and Santana, with striking virus-like symptoms similar to freesia leaf necrosis disease were received by the Virginia Tech Plant Disease Clinic from a cut-flower nursery in Gloucester, VA and forwarded for analysis to the USDA-ARS Floral and Nursery Plants Research Unit in Beltsville, MD. Approximately 25% of the plants had coalescing, interveinal, chlorotic, whitish, necrotic or dark brown-to-purple necrotic spots on leaves. Symptomatic plants were scattered within the planting. Fifteen symptomatic plants were collected between March and May of 2008, and nucleic acid extracts were analyzed for ophiovirus infection by reverse transcription (RT)-PCR with ophiovirus-specific degenerate primers (2). The diagnostic 136-bp ophiovirus product from the RdRp gene was amplified from 14 of 15 freesia plants tested. A partially purified virus preparation was analyzed by transmission electron microscopy and potyvirus- and ophiovirus-like particles were detected. The potyviruses, Freesia mosaic virus (FreMV) and Bean yellow mosaic virus (BYMV), each cause mosaic symptoms (3), although BYMV may induce necrosis late in the season. RT-PCR performed on the same nucleic acid samples using potyvirus coat protein (CP)-specific degenerate primers D335 and U335 (1) amplified the diagnostic 335-bp fragment from 2 of 15 plants. Cloned sequence from these plants was identified as FreMV. The ophiovirus CP gene was amplified by RT-PCR and cloned from two symptomatic freesia plants using primers FreSVf-CP-XhoI 5'-GACTCGAGAAATGTCTGGAAAATACTCTGTTC-3' and FreSVf-CP-BamHI 5'-CCAGGATCCTTAGATAGTGAATCCATAAGCTG-3', based on the sequence of Freesia sneak virus (FreSV) isolates from freesia (GenBank No. DQ885455) and lachenalia (4). The approximate 1.3-kb amplicon was cloned and sequences of two cDNA clones were identical (GenBank No. FJ807730). The deduced amino acid sequence showed 99% identity with the Italian FreSV CP sequence (GenBank No. DQ885455), confirming FreSV in the symptomatic freesia plants. To our knowledge, this is the first report of FreSV in Virginia and the United States. Soilborne freesia leaf necrosis disease has been reported in Europe since the 1970s (3); several viral causal agents have been hypothesized but recent findings correlate best with the ophiovirus. In Virginia, the presence of FreSV, but not FreMV, was strongly correlated with the leaf necrosis syndrome. FreSV, likely soilborne through Olpidium brassicae, may pose a new soilborne threat for bulbous ornamentals, since it has been recently detected also in Lachenalia spp. (Hyacinthaceae) from South Africa (4). Although specific testing of O. brassicae was not performed, the disease may potentially persist in the soil for years in O. brassicae resting spores and development of symptoms may be affected by environmental conditions (3). References: (1) S. A. Langeveld et al. J. Gen. Virol. 72:1531, 1991. (2) A. M. Vaira et al. Arch.Virol. 148:1037, 2003. (3) A. M. Vaira et al. Acta Hortic. 722:191, 2006. (4) A. M. Vaira et al. Plant Dis. 91:770, 2007.

Minimum training requirement in ultrasound imaging of peripheral arterial disease.

OBJECTIVES: To demonstrate the minimum training requirement when performing ultrasound of peripheral arterial disease. DESIGN: Prospective and blinded comparative study. MATERIAL: 100 limbs in 100 consecutive patients suffering from peripheral arterial disease, 74% suffering critical limb ischemia, were enrolled during a 9 months period. METHODS: One physician with limited ultrasound experience performed all the ultrasound examinations of the arteries of the most symptomatic limb. Before enrolling any patients 15 duplex ultrasound examinations were performed supervised by an experienced vascular technologist. All patients had a digital subtraction arteriography performed by an experienced vascular radiologist, unaware of the ultrasound result. RESULTS: The number of insufficiently insonated segments (non-diagnostic segments) was significantly reduced during the study; from 9% among the initial 50 limbs to 2% among the last 50 limbs (P<0.0001). This improvement was evident only in the infragenicular segments, as the performance within the supragenicular segments was good from the beginning. There was no change in the agreement between ultrasound and arteriography from the initial 50 patients (overall Kappa=0.66, (95%-CI: 0.60-0.72); supragenicular Kappa=0.73 (95%-CI: 0.64-0.82); infragenicular Kappa=0.61 (95%-CI: 0.54-0.69)) to the last 50 patients (overall Kappa=0.66 (95%-CI: 0.60-0.72), supragenicular Kappa=0.67 (95%-CI: 0.57-0.76); infragenicular Kappa=0.66 (95%-CI: 0.58-0.73)). CONCLUSION: The minimum training requirement in ultrasound imaging of peripheral arterial disease appears to be less than 50 ultrasound examinations (probably only 15 examinations) for the supragenicular segments and 100 examinations for the infragenicular segments.

First Report of Cephalosporium gramineum, Causal Agent of Cephalosporium Stripe of Wheat, in a Commercial Winter Wheat Field in Virginia.

Cephalosporium stripe (CS) (2) was identified in a commercial field of winter wheat (Triticum aestivum) near Riner, Montgomery County, Virginia in May 2006. Nearly 15% of the field was severely affected. Broad, yellow-brown stripes were observed on the leaf blades of affected plants, and many plants were stunted and had ripened prematurely. Symptomatic plants were associated with low acidic (pH 5.2), wet spots of the field. Leaves and nodes of affected plants were surface disinfested for 1 min in 5% sodium hypochlorite, plated on corn meal agar (CMA), and incubated at 20°C for 5 days. Cephalosporium gramineum was isolated from numerous plants. Cultures of the fungus produced hyaline conidiophores approximately 5 µm long and unicellular conidia 3 to 7 µm long. Aqueous suspensions of mycelia and conidia were prepared from pure cultures. Several spring wheat cultivars were wounded by severing the root mass and were inoculated when the fifth stem node was detectable (35 on Zadoks scale). Noninoculated plants were wounded as controls. Plants were kept in the greenhouse at temperatures of 22 to 27°C. After 14 days, inoculated plants produced symptoms of CS, and the fungus was reisolated from the leaves of these plants. No symptoms were observed on noninoculated control plants. Though CS had been observed in Virginia in research nurseries (1), to our knowledge, this is the first confirmed report of the disease in a commercial wheat field in Virginia. References: (1) J. B. Jones et al. Plant Dis. 64:325, 1980. (2) C. M. Stiles and T. D. Murray. Phytopathology 86:177, 1996.

In-situ bypass surgery on arteriographically invisible vessels detected by Doppler-ultrasound for limb salvage.

AIM: The aim of this paper was to evaluate our primary experience with bypass surgery on arteries only visible on Doppler-ultrasound in patients suffering from critical lower limb ischemia. METHODS: During a study period of 10 months, Doppler-ultrasound routinely supplemented digital subtraction arteriography (DSA) whenever it failed to reveal patent runoff vessels suitable for in-situ saphenous vein bypass surgery. If an arteriographically invisible runoff artery was detected on Doppler-ultrasound and the patient was eligible for surgery, a bypass procedure was performed. All patients were facing a lower limb amputation due to critical limb ischemia (tissue loss, SVS/ISCV-category 5). Postoperatively the patients were followed according to a standard graft surveillance program, including clinical examination, ankle pressure measurements and a color Doppler-ultrasound at discharge and after 1, 6 and 12 months. RESULTS: Fifty-one in-situ saphenous vein bypasses were performed, 5 (10%) on arteriographically occult runoff vessels detected only on Doppler-ultrasound. After a 12-month follow-up, 3 bypasses were still patent and only one patient had an amputation. One bypass occluded after 6 months but the patient stayed asymptomatic. CONCLUSIONS: Doppler-ultrasound permits in-situ by-pass surgery on arteriographically invisible vessels reducing the proportion of inoperable patients by 10%.

Identification of genes differentially expressed in testes containing carcinoma in situ.

Virtually all testicular germ cell tumours originate from a common precursor, the carcinoma in situ (CIS) cell. The precise nature of the molecular mechanisms leading to CIS remains largely unknown. We performed the first systematic analysis of gene expression in testis with CIS compared to normal testis by the differential display (DDRT-PCR) method, with subsequent analysis by RT-PCR and in situ hybridization (ISH). In tissue containing CIS we identified overexpression of 28 mRNA, some previously reported in CIS and a number of genes not previously described in germ cell neoplasia, including the novel expressed sequence tag (EST) OIC1 (Overexpressed In CIS). The genes could be grouped functionally into genes involved in cell growth, proliferation, differentiation, immunological response, and genes with unknown biological function. Examples of overexpressed genes are SFRP1 that is involved in Wnt signalling and IGFBP6, which is of importance for fetal growth and inhibits cell growth through insulin-like growth factor-II. ISH analysis showed that both mRNA were localized to CIS cells. The results of our search for differentially expressed genes in CIS demonstrated a number of genes linked to testicular development (e.g. DCN, IGFBP6, SFRP1, SALL1), supporting our hypothesis that the origin of CIS is probably associated with disturbances of the fetal development of the testis.

Germ cell differentiation-dependent and stage-specific expression of LANCL1 in rodent testis.

LANCL1 (LanC-like protein 1) is related to the bacterial LanC (lanthionine synthetase C) family, which is involved in the biosynthesis of antimicrobial peptides. Highest expression levels of LANCL1 are found in testes and brain, two organs that exist behind blood-tissue barriers. In the mouse, the establishment of an impermeable blood-testis barrier occurs between day 10-16 post natal (pn). Differential display analysis showed that the expression level of LANCL1 mRNA in mouse testes was very low until day 16 pn, but increased gradually from day 16 pn to reach a maximum on days 22-24 pn followed by a slight reduction from day 26 pn to adult animals. Thus, the expression of LANCL1 mRNA is initiated following the establishment of the blood-testis barrier. In situ hybridisation revealed that LANCL1 mRNA was induced in diplotene spermatocytes, which appear for the first time in mouse testes between days 18 and 20 pn, verifying the expression profile determined by differential display. LANCL1 mRNA level remained high in the meiotic division phase and in early round spermatids, but was down regulated in elongating spermatids and it was undetectable in step 9 elongating spermatids in stage IX (as defined by Russel et al., 1990). The steady decrease in expression level from round spermatids in stage I to elongating spermatids in stage IX suggested that LANCL1 mRNA was not transcribed in spermatids. LANCL1 expression in rat testes was initiated already in pachytene spermatocytes in stage IX, but otherwise similar to mouse.

Ultrasound contrast-agent improves imaging of lower limb occlusive disease.

OBJECTIVES: to evaluate if ultrasound contrast-agent infusion could improve duplex-ultrasound imaging of peripheral arterial disease (PAD) and increase the agreement with digital subtraction arteriography (DSA). DESIGN: prospective and consecutive study. MATERIAL: of 60 consecutive PAD patients, 15 were found to have an inconclusive duplex-ultrasound scan of the trifurcation and were included in the study. All 15 patients (53% male) were scheduled for DSA, all being candidates for vascular surgery due to claudication (n = 3, 20%), rest pain (n = 5, 33%) and tissue loss (n = 7, 47%). METHODS: on the day before DSA, a duplex-ultrasound scan of the trifurcation was performed. If the duplex-ultrasound scan was found inconclusive, it was repeated during continuous ultrasound contrast-agent infusion. DSA was performed unaware of the duplex-ultrasound results and served as the gold standard. RESULTS: after contrast-agent administration, the number of inconclusively diagnosed segments was significantly reduced by 26 (70%), from 37 to 11(p < 0.001). In 19 segments (73%) contrast-agent infusion changed the diagnosis in accordance with the DSA (p < 0.05). Values of sensitivity and positive predictive value were improved from 0.20 (0.04-0.62) to 0.47 (0.26-0.69) and 0.50 (0.10-0.91) to 0.80 (0.49-0.93), respectively. Specificity and negative predictive value were unchanged. Agreement between duplex-ultrasound and DSA were improved from poor (kappa = 0.18 (95% CI: 0-0.82)) to moderate (kappa = 0.45 (0.17-0.74)) (p = 0.44). CONCLUSION: ultrasound contrast-agents improve the diagnostic ability of duplex-ultrasound when scanning difficult arterial segments in patients suffering from PAD.

Ultrasound imaging of infrainguinal arterial disease has a high interobserver agreement.

OBJECTIVES: to evaluate and compare the operator dependency of duplex ultrasound and digital subtraction arteriography (DSA) in patients suffering from chronic lower limb ischaemia. DESIGN: prospective and blinded validation study. MATERIAL: twenty-six consecutive patients (13 male and 13 females) with severe claudication (n=6, 23%), rest pain (n=7, 27%) or tissue loss (n=13, 50%). METHODS: two physicians independently performed a duplex scan of the lower limb from groin to foot (15 segments). Segments were classified as insignificantly (<50% stenosis) or significantly (>50% stenosis or occlusion) diseased. DSA was performed within 24h of the duplex scanning and was independently reported by two radiologists in the same manner. Interobserver agreement was assessed for both diagnostic methods. After 10 months the arteriograms were reassessed and the intraobserver agreement calculated. RESULTS: for the limb as a whole the interobserver agreement was good and similar for both duplex and DSA, with kappa-values of 0.79 (95%-CI: 0.72-0.86) and 0.80 (0.74-0.87). In the femoral, crural and pedal segments the interobserver agreement was similar for both methods. The intraobserver agreement between the two DSA readings was 0.84 (0.79-0.90). CONCLUSION: ultrasound is comparable to arteriography when visualising arterial occlusive disease in patients with chronic lower limb ischaemia.

Posttranscriptional modifications in the A-loop of 23S rRNAs from selected archaea and eubacteria.

Posttranscriptional modifications were mapped in helices 90-92 of 23S rRNA from the following phylogenetically diverse organisms: Haloarcula marismortui, Sulfolobus acidocaldarius, Bacillus subtilis, and Bacillus stearothermophilus. Helix 92 is a component of the ribosomal A-site, which contacts the aminoacyl-tRNA during protein synthesis, implying that posttranscriptional modifications in helices 90-92 may be important for ribosome function. RNA fragments were isolated from 23S rRNA by site-directed RNase H digestion. A novel method of mapping modifications by analysis of short, nucleotide-specific, RNase digestion fragments with Matrix Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS) was utilized. The MALDI-MS data were complemented by two primer extension techniques using reverse transcriptase. One technique utilizes decreasing concentrations of deoxynucleotide triphosphates to map 2'-O-ribose methylations. In the other, the rRNA is chemically modified, followed by mild alkaline hydrolysis to map pseudouridines (psis). A total of 10 posttranscriptionally methylated nucleotides and 6 psis were detected in the five organisms. Eight of the methylated nucleotides and one psi have not been reported previously. The distribution of modified nucleotides and their locations on the surface of the ribosomal peptidyl transferase cleft suggests functional importance.