Using an agent-based sexual-network model to analyze the impact of mitigation efforts for controlling chlamydia

Chlamydia trachomatis (Ct) is the most reported sexually transmitted infection in the United States, with a major cause of infertility, pelvic inflammatory disease, and ectopic pregnancy among women. Despite decades of screening women for Ct, rates increase among young African Americans (AA). We create and analyze a heterosexual agent-based network model to help understand the spread of Ct. We calibrate the model parameters to agree with survey data showing Ct prevalence of 12% of the women and 10% of the men in the 15-25 year-old AA in New Orleans, Louisiana. Our model accounts for both long-term and casual partnerships. The network captures the assortative mixing of individuals by preserving the joint-degree distributions observed in the data. We compare the effectiveness of intervention strategies based on randomly screening men, notifying partners of infected people, which includes partner treatment, partner screening, and rescreening for infection. We compare the difference between treating partners of an infected person both with and without testing them. We observe that although increased Ct screening, rescreening, and treating most of the partners of infected people will reduce the prevalence, these mitigations alone are not sufficient to control the epidemic. The current practice is to treat the partners of an infected individual without first testing them for infection. The model predicts that if a sufficient number of the partners of all infected people are tested and treated, then there is a threshold condition where the epidemic can be mitigated. This threshold results from the expanded treatment network created by treating an individual's infected partners' partners. Although these conclusions can help design future Ct mitigation studies, we caution the reader that these conclusions are for the mathematical model, not the real world, and are contingent on the validity of the model assumptions.

Generating Bipartite Networks with a Prescribed Joint Degree Distribution

We describe a class of new algorithms to construct bipartite networks that preserves a prescribed degree and joint-degree (degree-degree) distribution of the nodes. Bipartite networks are graphs that can represent real-world interactions between two disjoint sets, such as actor-movie networks, author-article networks, co-occurrence networks, and heterosexual partnership networks. Often there is a strong correlation between the degree of a node and the degrees of the neighbors of that node that must be preserved when generating a network that reflects the structure of the underling system. Our bipartite 2K (B2K) algorithms generate an ensemble of networks that preserve prescribed degree sequences for the two disjoint set of nodes in the bipartite network, and the joint-degree distribution that is the distribution of the degrees of all neighbors of nodes with the same degree. We illustrate the effectiveness of the algorithms on a romance network using the NetworkX software environment to compare other properties of a target network that are not directly enforced by the B2K algorithms. We observe that when average degree of nodes is low, as is the case for romance and heterosexual partnership networks, then the B2K networks tend to preserve additional properties, such as the cluster coefficients, than algorithms that do not preserve the joint-degree distribution of the original network.

Abstract P4-12-07: Neoadjuvant trastuzumab emtansine and docetaxel, with or without pertuzumab, in patients with HER2-positive early-stage breast cancer: Results from a phase 1b/2a study

Introduction

Trastuzumab emtansine (T-DM1) is an antibody–drug conjugate comprising trastuzumab, a stable linker, and DM1 (a microtubule inhibitor). T-DM1 prolonged PFS and OS compared with standard therapy in a phase 3 study in patients with human epidermal growth factor receptor 2 (HER2)–positive metastatic breast cancer (MBC) previously treated with trastuzumab and a taxane and was well tolerated (Verma, NEJM 2012). When combined with docetaxel (D) or pertuzumab (P), T-DM1 antitumor activity was enhanced in preclinical models of HER2-positive breast cancer (Lewis-Phillips, AACR 2008; Fields, AACR 2010). The feasibility of combining T-DM1 with D±P in patients with HER2-positive MBC and early-stage breast cancer (EBC) was demonstrated in phase 1b of study BP22572, in which the maximum tolerated doses (MTDs) were defined (Martin, SABCS 2012). Here we report on patients with EBC who were treated at the MTDs in phases 1b and 2a of the study.

Methods

BP22572 is a phase 1b/2a open-label, multicenter study evaluating neoadjuvant T-DM1 with D±P in patients with centrally confirmed HER2-positive EBC (clinical stage IIa–IIIc) who have not received prior anticancer therapy. Patients with EBC were treated for up to 6 cycles at the doses specified in the Table.

Results

Recruitment into the neoadjuvant cohorts was completed in November 2012; the data cutoff date for analyses presented here was May 2, 2013. A total of 70 patients were treated with the combinations (median age, 51.5 years [range, 34–76]). Grade 3/4 adverse events (AEs) were reported for 51 (72.9%) patients; those occurring in >1 patient are shown in the Table. One patient in the T-DM1 + D 100 mg/m2 cohort experienced grade 5 pneumonitis shortly after an episode of neutropenic fever. As of the data cutoff date, all patients had received neoadjuvant treatment, but not all had undergone surgery. Pathologic complete response (pCR; ypT0/is ypN0, absence of invasive disease or in situ disease only in the breast and negative axillary nodes) was achieved in 40 of 70 treated patients (preliminary pCR rate, 57.1%).

Grade 3/4 AEs occurring in >1 patientAE, n (%)All patients (N = 70)T-DM1 3.6 mg/kg + D 75 mg/m2 q3w (n = 15)T-DM1 3.6 mg/kg + D 100 mg/m2 q3w (with G-CSF) (n = 22)T-DM1 3.6 mg/kg + D 60 mg/m2 + P 840 mg LD, then 420 mg q3w (n = 11)T-DM1 3.6 mg/kg + D 75 mg/m2 + P 840 mg LD, then 420 mg q3w (with G-CSF) (n = 22)Neutropenia21 (30)7 (47)2 (9)7 (64)5 (23)Thrombocytopenia14 (20)2 (13)6 (27)—6 (27)ALT increased11 (16)3 (20)3 (14)3 (27)2 (9)Asthenia6 (9)2 (13)2 (9)1 (9)1 (5)AST increased5 (7)2 (13)1 (5)—2 (9)Lymphopenia3 (4)—2 (9)—1 (5)Mucosal inflammation3 (4)—2 (9)—1 (5)Anemia2 (3)—1 (5)—1 (5)Febrile neutropenia2 (3)—1 (5)—1 (5)Leukopenia2 (3)1 (7)—1 (9)—Diarrhea2 (3)——1 (9)1 (5)

Conclusions

Grade 3/4 AE profiles were consistent with the known safety profiles of the 3 agents in patients with MBC. There was 1 grade 5 event (pneumonitis) in the T-DM1 + D 100 mg/m2 cohort. Preliminary pCR data are encouraging. Final safety and efficacy data from all patients in phase 2a of the study will be available for the presentation.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-12-07.

Abstract PD03-02: Evidence for the anti-cancer action of metformin mediated via tumor AMPK, Akt and Ki67, in a preoperative window of opportunity trial

Background: Metformin reduces the overall risk of cancer incidence by 31%, improves cancer-related mortality and enhances response to neoadjuvant chemotherapy in type 2-diabetics receiving metformin. There is evidence that metformin works through activation of Adenosine Monophosphate Protein Kinase (AMPK), an energy-sensing kinase that maintains cellular energy homeostasis. In a pre-operative window-of-opportunity randomized trial we have demonstrated that metformin significantly reduces proliferation and blunts the insulin response in primary operable breast cancer. This study further analysed cancer tissue from the trial to dissect the molecular mechanisms involved.

Methodology: Non-diabetic women with operable invasive breast cancer were randomised to receive pre-operative metformin or no drug. Forty seven patients had core biopsy at diagnosis then were randomized to metformin (metformin 500mg o.d. for 1 week increased to 1g b.d for a further week continued to surgery) or no drug, and 2 weeks later had core biopsy at surgery. Insulin receptor, phospho-AMPK (pAMPK), phospho-Akt (pAkt) and Ki67 immunohistochemistry was performed on formalin-fixed paraffin-embedded cores and scored blinded to treatment. Paired t-test was used for analysis.

Results: Significant up-regulation of pAMPK (p = 0.04) and down-regulation of pAkt (p = 0.04) in metformin treated patients was demonstrated compared to the control group. No change in insulin receptor expression was identified but, as previously reported, there was a fall in ki67. Changes were independent of Body Mass Index. Seven patients (7/24) receiving metformin withdrew because of gastro-intestinal upset and were excluded from the immunohistochemical analyses.

Conclusion: These findings suggest that metformin works in vivo in breast cancer patients via up-regulation of tumor pAMPK and down-regulation of pAkt and proliferation. Since down-regulation of pAMPK is a feature of breast cancer, this suggests mechanistic evidence for the therapeutic effect of metformin.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD03-02.

Impact of multidisciplinary team management in head and neck cancer patients

BACKGROUND

We analysed the outcomes of 726 cases of primary head and neck cancer patients managed between 1996 and 2008, including those managed in the multidisciplinary clinic or team setting (MDT) and those managed outside of an MDT by individual disciplines (non-MDT) in the same institution.

METHODS

Data were collected from the Hospital Based Cancer Registry and a database within the Head and Neck Cancer Clinic. Univariable comparisons and multivariable analyses were performed using a logistic regression model. Survival by staging was analysed. Comparisons of management and outcomes were made between MDT and non-MDT patients.

RESULTS

395 patients (54%) had been managed in the MDT vs 331 patients (46%) non-MDT. MDT patients were more likely to have advanced disease (likelihood ratio χ(2)=44.7, P<0.001). Stage IV MDT patients had significantly improved 5-year survival compared with non-MDT patients (hazard ratio=0.69, 95% CI=0.51-0.88, P=0.004) and more synchronous chemotherapy and radiotherapy (P=0.004), and the non-MDT group had more radiotherapy as a single modality (P=0.002).

CONCLUSIONS

The improved survival of MDT-managed stage IV patients probably represents both the selection of multimodality treatment and chemotherapeutic advances that these patients received in a multidisciplinary team setting by head and neck cancer specialists as opposed to cancer generalists in a non-MDT setting.

The Effect of Neoadjuvant Metformin on Breast Cancer Related Genes Clinical Trial – A Preliminary Result

Other authoring group: Dougal Adamson, Lee Baker, Douglas C Brown, Sally Chalmers, Amanda Degabriele, Janet Flinn, Kenneth Fowler, Avril Gunning, Grahame Hardie, Julie Lindsay, Gillian Little, Denis McLean, Robert Murdoch, Colin Purdie, Marta Reis, Valerie Walker.IntroductionMetformin, used in the treatment of diabetes for 50 years, has been linked to a reduced incidence of breast cancer and to an enhanced pathological response when administered concurrent with neoadjuvant chemotherapy. It has been postulated that the anti-neoplastic effect of metformin is through activation of AMP-activated protein Kinase (AMPK). The aim of this open label, randomised clinical trial was to investigate the effect of neoadjuvant metformin on gene expression in primary breast cancer.MethodsNon-diabetic women with histologically proven, operable, primary invasive breast cancer of ≥1cm in size were offered the trial following regional Research Ethics Committee approval.The trial had 2 arms, A and B: in arm A (8 patients), patients had core biopsies at three time points: one at presentation; one after a week of no treatment (internal control); and a further biopsy at the time of definitive surgery after at least 2 weeks of metformin. In trial arm B (47 patients), patients had core biopsies at two time points: one before randomisation to either take metformin or not, and one at the time of definitive breast surgery. Metformin was given as 500mg o.d. orally for one week, increased to 1g b.d. orally for at least another week and until the day prior to excisional breast surgery.RNA was extracted from formalin fixed cores and examined using a Disease-Specific Array for breast cancer on an Affymetrix platform (ALMAC Diagnostics Group, Craigavon, UK). Subsequent confirmatory polymerase chain reaction and immunohistochemistry techniques were used to examine the histological material.ResultsType of results expected:[Change of target gene expression in response to neoadjuvant metformin; symptomatic drug toxicities; potential for therapeutic effects of metformin in non-diabetic patients in vivo.]Results from the first arm:The triplet of core biopsies from 6/8 (75%) of the A arm patients passed the GeneGhip QC and data integrity assessment. Patients were 41-65 (mean: 53) years, with IDC NST, grade II-III, and all ER positive. 270 genes were differentially expressed significantly by wounding, and 63 by metformin. Among the genes significantly over-expressed by metformin were AMPK-beta and PI3K; and those down regulated by metformin were AMPK-gamma and ADCY1. Samples from the B arm patients are in analysis.ConclusionThe gene expression changes identified in response to neoadjuvant metformin suggest that metformin improves DNA damage recognition and repair and regulates cancer cell metabolism. These results suggest mechanisms by which metformin could be efficacious in the treatment of breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3145.

Epidemiology of rotavirus infection in north-western Nigeria

Rotaviruses (RV) are associated with approximately 33 000 deaths in children <5 years of age annually in Nigeria. However, limited data exit on RV infection in north-western Nigeria. During July 2002 to July 2004, 1063 (869 diarrhoeic and 194 control) stool samples were collected from children <5 years of age presenting with diarrhoea in north-western Nigeria. The stools were analysed for RV antigen and further characterized by antigenic and genomic methods. RV was detected in 18% of children with diarrhoea and 7.2% of the age-matched case controls. The highest RV burden was detected in children <6-months-old. Long electropherotypes and VP6 subgroup I + II specificity predominated.

The development of a healthy eating indicator shopping basket tool (HEISB) for use in food access studies—identification of key food items

Objectives

To develop an objective, nutrient-based, healthy eating indicator shopping basket (HEISB) tool for use in studies of access to healthy food.

Design

Tool development used a literature search to identify previous practice, web information on current definition of healthy foods by the UK Food Standards Agency, and population-based dietary surveys to identify culturally acceptable foods. These findings were then appraised with respect to practical fieldwork considerations.

Setting

The review took account of surveys undertaken in a range of geographical areas.

Results

Previous tools have varied in the foods selected and the rationale for inclusion. Most have considered nutritional composition but no systematic definition has been used and foods have been subjectively classified as ‘less healthy’ or ‘more healthy’. Recent UK work on nutrient profiling enabled individual food items to be objectively assessed for inclusion. Data from national food surveys enabled commonly consumed and culturally acceptable foods to be identified. Practical considerations included item use in meals, convenience, price, and fieldwork constraints. Other issues including health and price discriminators as well as regional preferences were considered. The final HEISB tool comprised 35 items within the following categories – 17 from fruit and vegetables, nine from potatoes, bread and cereal, five from fish/meats, three from dairy, and one from fatty and sugary foods.

Conclusions

The tool provides a rational basis for examining access and availability of healthy foods in cross-sectional and longitudinal retail and consumer studies.

Radiotherapy following breast-conserving surgery for screen-detected ductal carcinoma in situ: indications and utilisation in the UK. Interim findings from the Sloane Project

Use of radiotherapy (RT) after breast-conserving surgery (BCS) for ductal carcinoma in situ (DCIS) varies according to country, precedent and prejudice. Results from a preliminary analysis of the data available within the UK Sloane Project can be appreciated in the context of the uncertainty concerning the selection of adjuvant RT following BCS for DCIS. There was a marked geographical variation in the use of RT within the United Kingdom. However, overall, patients with DCIS treated with BCS were significantly more likely to have RT planned (and given) if they had large (⩾15 mm), intermediate or high-grade tumours or if central comedo-type necrosis was present. Unexpectedly, margin width did not appear to have a significant effect on the decision-making process. However, the Van Nuys Prognostic Index did significantly affect the chances of getting planned RT in the univariate analysis, suggesting that clinicians may be starting to use this scoring system in routine practice to assist in decision making.

Group A rotavirus strains circulating in the eastern center of Tunisia during a ten-year period (1995-2004)

An epidemiological survey investigating rotavirus infections in children was undertaken in the Eastern Center of Tunisia between January 1995 and December 2004. A total of 982 faecal specimens collected from children less than 5 years in age were screened by enzyme-linked immunosorbent assay (ELISA) or latex agglutination assay for the presence of group A rotavirus antigen. Rotavirus-positive samples were used for G and P typing by multiplex semi-nested reverse transcription-PCR. Rotaviruses were detected in 22% (n = 220) of stools. Of these, 164 were typed for VP7: G genotypes found were G1 (59%), G2 (2%), G3 (9%), G4 (10%), G8 (1%), and G9 (1%). Sixteen specimens (9%) showed mixed G profiles. A total of 119 specimens were typed for VP4. P genotypes detected were P[8] (32%), P[6] (15%), and P[4] (13%). Mixed P profiles were also detected (6%). Although the distribution of the detected genotypes appeared to change annually, G1P[8] rotavirus strains always predominated during the 10-year period of study. This is the first report of rotaviruses in Tunisia with unconventional VP7 serotypes such as G8 and G9, highlighting the need for continual surveillance of emerging strains in Northern Africa. Indeed, the new commercial vaccines only contain the VP7 genes that dictate G1 or G1 to G4 specificities. These vaccines may protect less well against unusual strains circulating in countries planning to implement a rotavirus vaccine strategy.

[Prevalence of adenovirus antigens in children presenting with acute diarrhoea]

Viral diarrhoea remains a major cause of childhood morbidity and mortality worldwide. Four major categories of viruses are now recognized as clinically important, including rotavirus, astrovirus, adenovirus, and calicivirus. This retrospective epidemiological study was conducted in the East centre part of Tunisia. A total of 638 stool samples were collected from children under 5 years of age presenting with acute diarrhoea at hospitals the East centre part of Tunisia between October 2003 and September 2005. All samples were analyzed using commercially available immunoenzymatic assay (EIA) kits to detect specific adenovirus antigens. Samples positive for adenovirus antigen were further screened using an ELISA technique allowing specific detection of species F enteric adenovirus types 40 and 41. Adenovirus was detected in 6% of the stools tested using ELISA. Among stool samples testing positive for adenovirus, 57% (20/35) were found to contain species F adenovirus types 40/41. In addition to diarrhoea that was present in all children studied, vomiting and fever were observed in 89% and 53% respectively and were associated with respiratory troubles in 32%. Enteric adenoviruses appear to play an important role in paediatric diarrhoea in Tunisia. Use of simple effective viral diagnostic techniques in paediatric hospitals could improve patient care by reducing unnecessary use of antibiotics.

Molecular characterisation of the rotavirus strains prevalent in Maua, Meru North, Kenya

BACKGROUND

Rotavirus is the most common cause of severe infantile diarrhoea disease in infants and young children below five years worldwide. Rotavirus is associated with high cases of morbidity and mortality and it is estimated that up to 650,000 deaths in young children occur annually in the less developed countries and approximately 150,000-200,000 deaths occur in Africa alone.

OBJECTIVE

To characterise the circulating rotavirus strains in Maua, Meru North district, Kenya.

DESIGN

A prospective study to investigate and characterise rotavirus serotypes/genotypes and electropherotypes in infants and children with severe diarrhoea hospitalised and/or attending the outpatient department of Maua Methodist Hospital during the period April 2004 to September 2005.

SETTING

Maua Methodist Hospital, Meru North, Kenya.

SUBJECTS

Faecal samples were collected from 135 infants and children with acute diarrhoea and were screened first for the presence of human Group A rotavirus antigen using commercially available enzyme linked immunosorbent assay kit (ELISA). The positive samples were evaluated by sodium dodecyl polycrylamide gel electrophoresis (SDS-PAGE) to determine the viral RNA electropherotype profile. Rotavirus strains were also genotyped using reverse transcriptase polymerase chain reaction (RT-PCR) of the VP7 gene.

RESULTS

Assay of these samples with commercial ELISA showed that 17.8% (24/135) were positive for group A rotavirus antigen. Twenty of these ELISA positive samples were also analysed by SDS-PAGE of which 75% (15/20) gave detectable electropherotype pattern with the long electropherotype being predominant 80.0% (12/15) followed by the short RNA profile 20.0% (2/ 15). Seventeen of the ELISA positive samples were genotyped for VP7 and the results showed that G9 was the most predominant genotype comprising 47.1% (8/17) followed by G8 29.4% (5/17), GI 17.4% (3/17) and the mixed genotype was G8/G9 5.9% (1/17). Most patients with rotavirus infection were of the age of 3 - 60 months, with 79% being less than 18 months old.

CONCLUSION

The overall prevalence of rotavirus infection in young children with diarrhoea hospitalised and/or attending the out-patient department of Maua Methodist Hospital was 17.8% with the predominant serotype being G9. These results show that rotavirus plays an important role in severe viral diarrhoea in young children in Maua Meru North district, Kenya. Furthermore, this high G9 rotavirus prevalence in Kenya may require vaccine trials to be held in Kenya so as to determine the efficacy of new rotavirus vaccine candidates that do not include the G9 serotype.

Identification of viral agents causing diarrhea among children in the Eastern Center of Tunisia

Viral diarrhea remains a major cause of childhood morbidity and mortality worldwide. In Tunisia, no comprehensive studies of all viral agents related to diarrhea in children have yet been conducted. The present study was performed to investigate the role of enteric viruses in acute diarrhea in the country. Six hundred thirty-eight stool samples were collected from children under 5 years of age seeking medical care for acute diarrhea between October 2003 and September 2005 in hospitals from the Eastern-Center Tunisia. All samples were tested for rotavirus, astrovirus, and adenovirus using commercial antigen enzyme immunoassays (EIAs). Positive samples for rotavirus and astrovirus were confirmed by an "in-house" reverse transcriptase-polymerase chain reaction (RT-PCR). Samples positive for adenovirus antigen were subjected to further EIA screening for species F enteric adenovirus types 40 and 41. At least one viral agent was found in 30% of the specimens. The frequency of rotavirus, astrovirus, and adenovirus was 20%, 7%, and 6%, respectively. Of the stool samples containing adenovirus, 57% (20/35) were found to be positive for species F adenovirus types 40/41. Dual infections were found in 9% (17/191) of the positive samples. Enteric viruses appear to play an important role in pediatric diarrhea in Tunisia. The introduction of affordable viral diagnosis in pediatric hospitals will improve patient care by reducing the unnecessary use of antibiotics.

Pathology reporting of breast cancer: trends in 1989-1999, following the introduction of mammographic screening in Western Australia

BACKGROUND

A survey of pathology reporting of breast cancer in Western Australia in 1989 highlighted the need for improvement. The current study documents (1) changes in pathology reporting from 1989 to 1999 and (2) changes in patterns of histopathological prognostic indicators for breast cancer following introduction of mammographic screening in 1989.

METHODS

Data concerning all breast cancer cases reported in Western Australia in 1989, 1994 and 1999 were retrieved using the State Cancer Registry, Hospital Morbidity data system, and pathology laboratory records.

RESULTS

Pathology reports improved in quality during the decade surveyed. For invasive carcinoma, tumour size was not recorded in 1.2% of pathology reports in 1999 compared with 16.1% in 1989 (p<0.001). Corresponding figures for other prognostic factors were: tumour grade 3.3% and 51.6% (p<0.001), tumour type 0.2% and 4.1% (p<0.001), vascular invasion 3.7% and 70.9% (p<0.001), and lymph node status 1.9% and 4.5% (p = 0.023). In 1999, 5.9% of reports were not in a synoptic/checklist format, whereas all reports were descriptive in 1989 (p<0.001). For the population as a whole, the proportion of invasive carcinomas <1 cm was 20.9% in 1999 compared with 14.5% in 1989 (p<0.001); for tumours <2 cm the corresponding figures were 65.4% and 59.7% (p = 0.013). In 1999, 30.5% of tumours were histologically well-differentiated compared with 10.6% in 1989 (p<0.001), and 61.7% were lymph node negative in 1999 compared with 57.1% in 1989 (p = 0.006). Pure ductal carcinoma in situ (DCIS) constituted 10.9% and 7.9% of total cases of breast carcinoma in 1999 and 1989, respectively (p = 0.01).

CONCLUSIONS

Quality of pathology reporting improved markedly over the period, in parallel with adoption of standardised synoptic pathology reports. By 1999, recording of important prognostic information was almost complete. Frequency of favourable prognostic factors generally increased over time, reflecting expected effects of mammographic screening.

Cisplatin and gemcitabine induction chemotherapy followed by concurrent chemoradiotherapy or surgery for locally advanced non-small cell lung cancer

BACKGROUND

We report a study of induction chemotherapy followed by concurrent chemoradiotherapy for stage IIIA/IIIB non-small cell lung cancer.

METHODS

Patients received two cycles of induction chemotherapy with cisplatin 100 mg/m(2) on day 1 and gemcitabine 1000 mg/m(2) on days 1, 8, and 15 of a 28-day cycle. If the disease was resectable [corrected] surgery was followed with two further cycles. If unresectable, patients received cisplatin 100 mg/m(2) day 1, 29 with 5-fluorouracil 1000 mg/m(2) per 24 h continuous infusion for 96 h on days 2-5 and days 30-33 of the radiotherapy administration. Radiation therapy consisted of 63 Gy, 35 fractions, 7 weeks.

RESULTS

Of 48 patients, 40% had a partial response to induction chemotherapy. Four of eleven patients with stage IIIA tumours had resectable disease. The remaining seven patients plus 37 with stage IIIB disease had chemoradiotherapy. Response at the completion of all therapy was 62% (IIIA 73%, IIIB 59%). For all patients the median survival was 15.3 months: 1 year and 3 years, 58% and 25%, respectively. Those with IIIB disease responding to induction chemotherapy had significantly superior survival to those that did not respond (37 months vs 11 months; P = 0.005). This remained significant from a landmark at 8 weeks after the start of treatment (P = 0.01).

CONCLUSION

These results are equivalent to other studies using induction chemotherapy prior to concurrent chemoradiotherapy. Response to induction chemotherapy may have major prognostic significance.

Detection of Group A Rotavirus Strains Circulating in Calves in Tunisia

Faecal samples were collected from 89 dairy calves to determine the prevalence of rotavirus infection in Tunisia and the genomic diversity of bovine rotavirus strains. After screening of all faecal samples by enzyme-linked immunosorbent assay, rotavirus strains were analysed by RNA polyacrylamide gel electrophoresis and characterized antigenically by monoclonal antibodies to the VP6 subgroup. The VP7 genotype was determined by nested RT-PCR. Of the 89 calves tested, 27 (30%) were positive for rotavirus antigen. Four different long electrophoretypes were identified. All VP6 typeable strains carried the subgroup I specificity. G8 genotype was the most prevalent, but G6 and mixed strains G(6 + 8) were also detected.