Comparison between the radial forearm and superficial circumflex iliac artery perforator free flaps for oral soft tissue reconstruction.

The radial forearm free flap (RFFF) is widely used for oral reconstruction. The superficial circumflex iliac artery perforator (SCIP) flap is an increasingly utilized alternative. The cases of 165 patients who received either an RFFF or SCIP flap for oral reconstruction at Chris O'Brien Lifehouse, Sydney were reviewed. The aim was to report on patient, pathology, treatment, and outcome variables and to compare these between the two flap groups. A RFFF was used in 126 patients and a SCIP flap in 39 patients. SCIP flap patients were younger (P < 0.001) and had shorter operative times (P < 0.001), shorter anaesthetic times (P < 0.001), and more frequent recipient site dehiscence (P = 0.005) when compared to RFFF patients. The SCIP flap was significantly less frequently used for composite resections including bone when compared to the RFFF (P < 0.001). The primary site distribution was more even for RFFF patients (P < 0.001). There were no SCIP flap failures; three RFFF failures occurred. SCIP flaps performed comparably in terms of operative and clinical outcomes. Most SCIP flaps were utilized in younger patients with partial glossectomy defects.

A pilot study of intensive intervention using a novel trismus device.

PURPOSE: Trismus secondary to head and neck neoplasm treatment impacts upon quality of life, nutrition, oral hygiene, and dentition. Current treatment options for trismus apply unquantified force to the jaw, and in many cases, the device costs are prohibitive. This study aimed to prospectively evaluate the impact of a novel trismus device. METHOD: This single arm cohort study prospectively evaluated the impact of a novel trismus device on maximal incisal opening (MIO), trismus-related function and quality of life scores. Seventeen patients diagnosed with trismus were recruited to undergo a 10-week program using a novel device. The effect of the intervention was assessed by comparing pre- vs post-intervention validated measures. RESULT: A significant improvement in MIO was observed post the 10-week intervention period (12.6 mm). This was associated with an improvement in patient reported trismus symptomology including quality of life, swallowing, speech, and jaw pain. CONCLUSIONS: This pilot study demonstrates the feasibility of a novel device in the treatment of trismus. Further evaluation of this device is warranted to assess efficacy, safety, and cost-effectiveness in a larger cohort with appropriate controls.

Institutional-based and commercial virtual surgical planning in maxillomandibular reconstruction - Comparing the digital plan and postoperative scan.

BACKGROUND: Virtual surgical planning (VSP) is increasingly used in maxillomandibular osseous free flap reconstruction. Non-commercial ('in-house') VSP may offer the same level of accuracy and other benefits, without the inflated costs and time delays inherent in using commercial providers. Comparisons between commercial and in-house methods are lacking. This study aims to determine the accuracy of VSP, compare in-house and commercially planned cases, and explore predictors of the reconstruction error. METHODS: Seventy-six patients who had a virtually planned maxillomandibular reconstruction between January 2012 and July 2020 were retrospectively identified. The preoperative digital plan was compared to the postoperative CT scan in terms of length of bone segments, angle between adjacent segments and intercondylar, and intergonial angle distances (mandibular reconstructions only). RESULTS: Forty-four patients fulfilled the inclusion criteria. The mean intergonial and intercondylar distances error was 1.7 ± 1.01 mm, mean segment length error was 1.3 ± 1.40 mm, and mean angles error was 1.9 ± 2.32°. The difference in error of in-house VSP compared to commercial VSP was not statistically significant for intercondylar and intergonial distance (p = 0.76), segment length (p = 0.15), or angle between segments (p = 0.92). The increased error was associated with osteoradionecrosis as the indication for surgery, greater number of segments, and secondary reconstructions. CONCLUSION: VSP is an accurate method of maxillary and mandibular reconstruction. In-house VSP may be similar in accuracy to commercial VSP options. Higher levels of inaccuracy are likely to occur in more complex reconstructions, particularly secondary reconstructions, and in the setting of osteoradionecrosis.

The impact of radical parotidectomy with immediate facial nerve reconstruction: a quality-of-life measure.

OBJECTIVE: Immediate facial nerve reconstruction is the standard of care following radical parotidectomy; however, quality of life comparisons with those undergoing limited superficial parotidectomy without facial nerve sacrifice is lacking. METHOD: Patients who underwent parotidectomy were contacted to determine quality of life using the University of Washington Quality of Life and Parotidectomy Specific Quality of Life questionnaires. A total of 29 patients (15 in the radical parotidectomy and 14 in the limited superficial parotidectomy groups) completed and returned questionnaires. RESULTS: Using the University of Washington Quality of Life Questionnaire, similar quality of life was noted in both groups, with the radical parotidectomy group having significantly worse speech and taste scores. Using the Parotidectomy Specific Quality of Life Questionnaire, the radical parotidectomy group reported significantly worse speech, eye symptoms and eating issues. CONCLUSION: Those undergoing radical parotidectomy with reconstruction had comparable overall quality of life with the limited superficial parotidectomy group. The Parotidectomy Specific Quality of Life Questionnaire better identified subtle quality of life complaints. Eye and oral symptoms remain problematic, necessitating better rehabilitation and more focused reconstructive efforts.

Comparative Pathogenomics of Escherichia coli: Polyvalent Vaccine Target Identification through Virulome Analysis.

Comparative genomics of bacterial pathogens has been useful for revealing potential virulence factors. Escherichia coli is a significant cause of human morbidity and mortality worldwide but can also exist as a commensal in the human gastrointestinal tract. With many sequenced genomes, it has served as a model organism for comparative genomic studies to understand the link between genetic content and potential for virulence. To date, however, no comprehensive analysis of its complete "virulome" has been performed for the purpose of identifying universal or pathotype-specific targets for vaccine development. Here, we describe the construction of a pathotype database of 107 well-characterized completely sequenced pathogenic and nonpathogenic E. coli strains, which we annotated for major virulence factors (VFs). The data are cross referenced for patterns against pathotype, phylogroup, and sequence type, and the results were verified against all 1,348 complete E. coli chromosomes in the NCBI RefSeq database. Our results demonstrate that phylogroup drives many of the "pathotype-associated" VFs, and ExPEC-associated VFs are found predominantly within the B2/D/F/G phylogenetic clade, suggesting that these phylogroups are better adapted to infect human hosts. Finally, we used this information to propose polyvalent vaccine targets with specificity toward extraintestinal strains, targeting key invasive strategies, including immune evasion (group 2 capsule), iron acquisition (FyuA, IutA, and Sit), adherence (SinH, Afa, Pap, Sfa, and Iha), and toxins (Usp, Sat, Vat, Cdt, Cnf1, and HlyA). While many of these targets have been proposed before, this work is the first to examine their pathotype and phylogroup distribution and how they may be targeted together to prevent disease.

'Out of house' virtual surgical planning for mandible reconstruction after cancer resection: is it oncologically safe?

The purpose of this study was to investigate whether the time delay between 'out of house' proprietary virtual surgical planning (OH-VSP) of the mandibular resection for oral cancer and the actual surgery results in compromised margins and oncological disadvantage for the patient. Outcomes of patients who had OH-VSP of their mandibular resection and reconstruction were compared with those of patients who had the same surgery using a conventional non-VSP approach. The groups were similar in patient demographics, tumour stage and size, nodal status, and reconstruction complexity. VSP resulted in a significant reduction in operating time (P<0.01). VSP did not affect bony (P=0.49) or soft tissue (P=0.22) margin status. In summary, VSP reduced the operating theatre time, and despite the time interval between bony resection planning and surgery, there was no compromise to the oncological safety of the operation.

The Sydney Modified Alberta Reconstruction Technique (SM-ART) for dental rehabilitation following mandibulectomy or maxillectomy.

The Sydney Modification of the Alberta Mandibular Reconstruction technique (SM-ART) is a hybrid of the Rohner method and the Alberta Reconstructive Technique (ART). SM-ART differs from ART in three ways, notably the use of custom plates, intraoral placement of implants via three-dimensionally printed guides and a skin graft buried deep into the skin paddle of the fibula flap in the first stage of the reconstruction.

Elective neck dissection versus observation for early-stage oral squamous cell carcinoma: Systematic review and meta-analysis.

INTRODUCTION: Oral squamous cell carcinoma (OSCC) is the seventh most common cancer globally, and has been identified as a growing health concern. This study aims to evaluate the current literature comparing elective neck dissection to observation in the treatment of early-stage tongue SCC, focusing on nodal recurrence, overall survival, disease specific survival statistics from randomised controlled trials comparing the two interventions. METHODS: Systematic review and meta-analysis was conducted according to PRISMA guidelines. The odds ratio (OR) was used as a summary statistic. RESULTS: From 8 studies, there was a total of 372 cases of recurrence, 98 (15.1%) in END group and 274 (41.5%) in the Observation group. There was a significantly lower rate of recurrence in the END group compared to observation (OR 0.25, 95% CI 0.16-0.39, I2 = 54%, P < 0.00001). END was associated with higher overall survival rates when compared with observation (OR 1.95, 95% CI 1.40-2.73, I2 = 14%, P < 0.0001). END was also associated with higher disease-specific survival compared with observation (OR 1.88, 95% CI 1.21-2.93), I2 = 47%, P = 0.005), with no significant heterogeneity noted. CONCLUSIONS: END was associated with significantly lower recurrence rates and higher overall and disease-specific survival compared to a conservative observation approach in early-stage oral SCC with clinically N0 neck.

Prognostic Performance of Current Stage III Oral Cancer Patients After Curative Intent Resection: Evidence to Support a Revision of the American Joint Committee on Cancer Staging System.

BACKGROUND: The American Joint Committee on Cancer (AJCC) stage III classification of oral cavity squamous cell carcinoma (OCSCC) represents a heterogeneous group of patients with early local disease with regional metastases (T1N1 and T2N1) and advanced local disease with or without regional metastasis (T3N0 and T3N1). OBJECTIVE: The aim of this study was to evaluate prognostic heterogeneity in the stage III category. METHODS AND PATIENTS: An international retrospective multicenter study of 1815 patients who were treated for OCSCC from 2003 to 2011. RESULTS: Kaplan-Meier survival analysis and multivariate models of stage III patients revealed better overall survival (OS; HR 2.12, 95 % CI 1.03-4.15; p = 0.01) and disease-specific survival (DSS; HR 1.7, 95 % CI 1.16-4.12; p = 0.04) rates for patients with T1-2N1/T3N0 disease than for patients with T3N1 disease. The outcomes of patients with T3N1 and stage IVa disease were similar (p = 0.89 and p = 0.78 for OS and DSS, respectively). Modifying stage classification by transferring the T3N1 category to the stage VIa group resulted in a better prognostic performance [Harrell's concordance index, C index 0.76; Akaike's Information Criterion (AIC) 4131.6] compared with the AJCC 7th edition staging system (C index 0.65; AIC 4144.9) for OS. When DSS was assessed, the suggested staging system remained the best performing model (C index 0.71; AIC 1061.3) compared with the current AJCC 7th edition staging (C index 0.64; AIC 1066.2). CONCLUSIONS: The prognosis of T3N1 and stage IVa disease are similar in OCSCC, suggesting that these categories could be combined in future revisions of the nodal staging system to enhance prognostic accuracy.

Lymph node density in oral cavity cancer: results of the International Consortium for Outcomes Research.

BACKGROUND: Lymph node density (LND) has previously been reported to reliably predict recurrence risk and survival in oral cavity squamous cell carcinoma (OSCC). This multicenter international study was designed to validate the concept of LND in OSCC. METHODS: The study included 4254 patients diagnosed as having OSCC. The median follow-up was 41 months. Five-year overall survival (OS), disease-specific survival (DSS), disease-free survival (DFS), locoregional control and distant metastasis rates were calculated using the Kaplan-Meier method. Lymph node density (number of positive lymph nodes/total number of excised lymph nodes) was subjected to multivariate analysis. RESULTS: The OS was 49% for patients with LND0.07 compared with 35% for patients with LND>0.07 (P<0.001). Similarly, the DSS was 60% for patients with LND0.07 compared with 41% for those with LND>0.07 (P<0.001). Lymph node density reliably stratified patients according to their risk of failure within the individual N subgroups (P=0.03). A modified TNM staging system based on LND ratio was consistently superior to the traditional system in estimating survival measures. CONCLUSION: This multi-institutional study validates the reliability and applicability of LND as a predictor of outcomes in OSCC. Lymph node density can potentially assist in identifying patients with poor outcomes and therefore for whom more aggressive adjuvant treatment is needed.

Genetic map of the primocane-fruiting and thornless traits of tetraploid blackberry.

Blackberry primocane fruiting, fruiting on first-year canes, has the potential to expand blackberry production both seasonally and geographically. The incorporation of the primocane-fruiting trait into cultivars with desirable horticultural attributes is challenging due to its recessive nature and tetrasomic inheritance. Molecular marker-assisted selection has high potential to facilitate incorporation, because breeders already use morphological marker-assisted selection of seedlings without marginal cotyledonary hairs to identify progeny that will be thornless when mature. The development of a genetic linkage map with these two traits is the first step to utilizing molecular markers in breeding for thornless primocane-fruiting blackberry cultivars. A full-sib family segregating for thornlessness and primocane fruiting, from a cross between 'APF-12' and 'Arapaho', was used to construct the first genetic map of tetraploid blackberry. Segregation patterns of several dominant markers and the two phenotypic traits fit those expected uniquely with tetrasomic inheritance (e.g., 5:1, 11:1 and 35:1). Some loci showed significant double reduction frequencies, but genotypes that could have originated only from double reduction were not found. The map consists of seven linkage groups (LG) in each parent, consistent with the basic number of chromosomes (2n = 4x = 28). Naming of LG1-LG6 followed that of the recently revised system for raspberry using SSR markers in common between blackberry and raspberry, and LG7 was tentatively defined by default. The loci controlling primocane fruiting and thornlessness were not linked to each other; thornless/thorny, the S Locus, was mapped on LG4, and the primocane-/floricane-fruiting locus, named in this work the F Locus, on LG7.

Clinical nodal stage is a significant predictor of outcome in patients with oral cavity squamous cell carcinoma and pathologically negative neck metastases: results of the international consortium for outcome research.

BACKGROUND: We aimed to study the importance of clinical N classification (cN) in a subgroup of patients with oral cavity squamous cell carcinoma (OSCC) and pathologically negative neck nodes (pN-). METHODS: A total of 2,258 patients from 11 cancer centers who underwent neck dissection for OSCC (1990-2011) had pN- disease. The median follow-up was 44 months. 5-year overall survival (OS), disease-specific survival (DSS), disease free survival, local control, locoregional control, and distant metastasis rates were calculated by the Kaplan-Meier method. cN classification and tumor, node, metastasis classification system staging variables were subjected to multivariate analysis. RESULTS: A total of 345 patients were preoperatively classified as cN+ and 1,913 were classified as cN-. The 5-year OS and DSS of cN- patients were 73.6 and 82.2 %, respectively. The 5-year OS and DSS of cN+ patients were 64.9 and 76.9 %, respectively (p < 0.0001 each). A cN+ classification was a significant predictor of worse OS (p = 0.03) and DSS (p = 0.016), regardless of treatment, depth of invasion, or extent of neck dissection. cN classification was associated with recurrence-free survival (p = 0.01) and locoregional (neck and primary tumor) control (p = 0.004), but not with local (p = 0.19) and distant (p = 0.06) recurrence rates. CONCLUSIONS: Clinical evidence of neck metastases is an independent predictor of outcome, even in patients with pN- nodes.

Nitrogen cycle feedbacks as a control on euxinia in the mid-Proterozoic ocean.

Geochemical evidence invokes anoxic deep oceans until the terminal Neoproterozoic ~0.55 Ma, despite oxygenation of Earth's atmosphere nearly 2 Gyr earlier. Marine sediments from the intervening period suggest predominantly ferruginous (anoxic Fe(II)-rich) waters, interspersed with euxinia (anoxic H(2)S-rich conditions) along productive continental margins. Today, sustained biotic H(2)S production requires NO(3)(-) depletion because denitrifiers outcompete sulphate reducers. Thus, euxinia is rare, only occurring concurrently with (steady state) organic carbon availability when N(2)-fixers dominate the production in the photic zone. Here we use a simple box model of a generic Proterozoic coastal upwelling zone to show how these feedbacks caused the mid-Proterozoic ocean to exhibit a spatial/temporal separation between two states: photic zone NO(3)(-) with denitrification in lower anoxic waters, and N(2)-fixation-driven production overlying euxinia. Interchange between these states likely explains the varying H(2)S concentration implied by existing data, which persisted until the Neoproterozoic oxygenation event gave rise to modern marine biogeochemistry.

Local social capital and the acceptance of Protected Area policies: an empirical study of two Ramsar river delta ecosystems in northern Greece.

Managing Protected Areas (PAs) is a challenging task, and globally many instruments have been utilised for this purpose. Existing research demonstrates that the effectiveness of these instruments is highly dependent on their social acceptability among local communities resident within PAs. Consequently, investigating local attitudes and perceptions of Protected Area (PA) policies has been emphasised in recent studies. Drawing on empirical work conducted in two National Parks including river delta ecosystems designated as Ramsar wetlands in northern Greece, this paper examines local residents' perceptions of three hypothesized policy options (regulatory, market-based and participatory) for Park management. The influence of social capital elements (social trust, institutional trust and social networks) on residents' perceptions is explored. The findings reveal a high degree of importance attached by resident communities to Park designation in both PAs, though residents' perceptions of the proposed management options varied. The regulatory option was regarded as the least restrictive, while the most restrictive was perceived to be the market-based option. However, greater benefits were identified by residents from the market-based option, while the fewest benefits were considered to arise from the proposed regulatory option. Furthermore, local residents' perceptions were significantly shaped by the proposed management and decision-making structure offered under each policy option. The influence of different social capital elements on residents' perceptions also varied in the study sample, with social trust and institutional trust positively correlated with the benefits that were perceived to arise from the different policy options. Moreover, when social capital was measured as an aggregate indicator at the level of the individual, it was positively correlated with perceived environmental benefits.

Human papillomavirus predicts outcome in oropharyngeal cancer in patients treated primarily with surgery or radiation therapy.

OBJECTIVE: This study examines the prognostic significance of human papillomavirus (HPV) in patients with locally advanced oropharyngeal squamous cell carcinoma (SCC) treated primarily with surgery or definitive radiotherapy. METHODS: One hundred and ninety-eight patients with Stage 3/4 SCC were followed up for recurrence in any form or death from any cause for between 1 and 235 months after diagnosis. HPV status was determined using HPV E6-targeted multiplex real-time PCR/p16 immunohistochemistry. Determinants of recurrence and mortality hazards were modelled using Cox's regression with censoring at follow-up dates. RESULTS: Forty-two per cent of cancers were HPV-positive (87% type 16). HPV predicted loco-regional control, event-free survival and overall survival in multivariable analysis. Within the surgery with adjuvant radiotherapy (n=110), definitive radiotherapy-alone (n=24) and definitive radiotherapy with chemotherapy (n=47) groups, patients with HPV-positive cancers were one-third or less as likely to have loco-regional recurrence, an event or to die of any cause as those with HPV-negative cancers after adjusting for age, gender, tumour grade, AJCC stage and primary site. The 14 patients treated with surgery alone were considered too few for multivariable analysis. CONCLUSION: HPV status predicts better outcome in oropharyngeal cancer treated with surgery plus adjuvant radiotherapy as well as with definitive radiation therapy±chemotherapy.

Phase I dose-finding study of paclitaxel with panitumumab, carboplatin and intensity-modulated radiotherapy in patients with locally advanced squamous cell cancer of the head and neck.

BACKGROUND: Panitumumab has the potential to improve the therapeutic ratio of concurrent chemoradiotherapy for squamous cell carcinoma of the head and neck (SCCHN). PATIENTS AND METHODS: This phase I dose-finding study investigated escalating doses of paclitaxel (Taxol) given concurrently with panitumumab, carboplatin and intensity-modulated radiotherapy (IMRT) for stage III-IVB SCCHN. Untreated patients with oral cavity, oropharynx, larynx, hypopharynx or unknown primaries were eligible. Additional eligibility criteria included measurable disease, good performance status and no contraindication to therapy. Patients received weekly fixed doses of panitumumab and carboplatin plus escalating doses of paclitaxel with IMRT. RESULTS: Nineteen patients were enrolled on to two dose levels (DLs): weekly paclitaxel 15 mg/m(2) (n = 3) and 30 mg/m(2) (n = 16). One dose-limiting toxicity occurred in DL 2, which was declared the maximum tolerated dose. All patients experienced mucositis, primarily grade 3 or more. Oral pain, xerostomia, dysphagia, weight loss, dermatitis, nausea and acneiform rash were frequent. All patients had partial response according to RECIST, whereas the overall complete clinical response rate was 95%. At median follow-up of 21 months, 18 of 19 patients (95%) remained disease free. CONCLUSIONS: Panitumumab, carboplatin, paclitaxel and IMRT are well tolerated and appear highly active in the treatment of SCCHN. Further study of this regimen in SCCHN is warranted.

Orthodontic referral behaviour of West Sussex dentists.

OBJECTIVES: 1) To examine the orthodontic referral behaviour of dentists and 2) to examine dentists' familiarity with the Index of Orthodontic Treatment Need (IOTN). DESIGN: Postal questionnaire survey. SETTING: West Sussex Primary Care Trust (PCT) from September to December 2006. SUBJECTS AND METHODS: Questionnaires were sent to all dentists listed on the West Sussex PCT database, except those assumed not to make orthodontic referrals (n = 325). RESULTS: Two hundred and twenty-nine questionnaires were returned, representing a 70% response rate. Fifty-two percent of dentists in West Sussex correctly identified which type of orthodontic provider to refer three different malocclusions using picture tests. Twenty percent of dentists made correct decisions on the timing of referral for three different malocclusions using picture tests. IOTN is not routinely used by 76% of West Sussex dentists when making an orthodontic referral. CONCLUSIONS: This study provides evidence that there is a need for postgraduate training or the development of referral guidelines to assist West Sussex dentists in making referrals for orthodontic treatment to the most appropriate provider at the most appropriate time. If dentists are to act as gatekeepers of orthodontic provision on the NHS there is a need to provide more support and education for them about the use of IOTN.

Running biomechanics: shorter heels, better economy.

Better running economy (i.e. a lower rate of energy consumption at a given speed) is correlated with superior distance running performance. There is substantial variation in running economy, even among elite runners. This variation might be due to variation in the storage and reutilization of elastic energy in tendons. Using a simple musculoskeletal model, it was predicted that the amount of energy stored in a tendon during a given movement depends more critically on moment arm than on mechanical properties of the tendon, with the amount of stored energy increasing as the moment arm gets smaller. Assuming a link between elastic energy reutilization and overall metabolic cost of running, a smaller moment arm should therefore be associated with superior running economy. This prediction was confirmed experimentally in a group of 15 highly trained runners. The moment arm of the Achilles tendon was determined from standardized photographs of the ankle, using the position of anatomical landmarks. Running economy was measured as the rate of metabolic energy consumption during level treadmill running at a speed of 16 km h(-1). A strong correlation was found between the moment arm of the Achilles tendon and running economy. Smaller muscle moment arms correlated with lower rates of metabolic energy consumption (r(2)=0.75, P<0.001).

Recovery of Four Novel Potato spindle tuber viroid Sequence Variants from Russian Seed Potatoes.

First described in the early 1930s, the limited distribution of potato "gothic" disease made it of little economic significance in European Russia until the early 1970s when meristem-tip culture was widely adopted throughout the former USSR to increase production of virus-free seed potatoes. Shortly thereafter, the yield and quality of Russian seed potatoes began a dramatic decline. Symptoms of potato "gothic" resemble those of Potato spindle tuber viroid (PSTVd) (3), and initial suspicions that in vitro plantlets and seed potatoes might be viroid-infected were later proved correct when Kastalyeva et al. (2) showed that approximately 50 to 70% of in vitro plantlets and tubers collected from different regions of Russia as well as the in vitro germplasm collection maintained by the All-Russian Potato Research Institute (ARPRI) were infected with PSTVd. Measures have since been taken to reduce the incidence of PSTVd infection, and numerous PSTVd isolates were collected from territories of the former USSR; however, none of these isolates have been characterized at the molecular level. Overlapping reverse transcription (RT)-PCR products (1) were generated from four PSTVd isolates maintained in field-grown tubers at the VNIIF using two pairs of primers; PSTVd180F (5'-TCACCCTTCCTTTCTTCGGGTGTC-3') + PSTVd179R (5'-AAACCCTGTTTCGGCGGGAATTAC-3') and PSTVd112F (5'-ACT GGCAAAAAAGGACGGTGGGGA-3') + PSTVd359R (5'-AGGAACC AACTGCGGTTCCAAGGG-3'). Automated sequence analysis of the resulting uncloned PCR products revealed the presence of four previously unknown PSTVd variants (GenBank Accession Nos. EF044302-EF044305). All four tubers were also infected with Potato virus M and Potato virus Y and one tuber also contained Potato virus S. ELISA tests for Potato leaf roll virus were negative. Each isolate appeared to contain only a single 358-359 nt variant differing from PSTVd-intermediate strain (GenBank Accession No. V01465) at 2-5 positions. The three closely related variants originating from Leningradskaya Province (Northwest Russia) contain two to three changes in the variable domain and central conserved region and induced intermediate symptoms in Rutgers tomato. The fourth variant originating from Samarskaya Province (Volga River Region) contains additional changes in the pathogenicity domain and induced mild symptoms. Minor differences among the Leningradskaya variants may represent sequence drift during extended (9 to 11 year) tuber passage. The presence of additional sequence changes in the variant from Samarskaya is consistent with independent origin and/or prolonged separation. Additional studies with a wider range of Russian isolates of PSTVd are currently underway to develop diagnostic methods suitable for future large-scale screening programs. References: (1) Y. Hu et al. Virology 219:45, 1997. (2) T. B. Kastalyeva et al. Vestn. RASKHN 3:22, 1992. (3) Y. A. Leontyeva. Potato spindle tuber ('gothic') as one of the most important diseases in the Volga region. (In Russian.) Ph.D. thesis. Agricultural University of Leningrad, Pushkin, 1971.