Sequential autoprocessing of Marek's disease herpesvirus protease differs from that of other herpesviruses

Herpesviruses encode a unique serine protease essential for viral capsid maturation. This protease undergoes autoprocessing at two sites, R and M, at the consensus sequence (V, L, I)(P3)-X(P2)-A(P1)/S(P1') (where X is a polar amino acid). We observed complete autoprocessing at the R and M sites of Marek's disease virus (MDV) protease following production of the polyprotein in Escherichia coli. Site-directed mutagenesis confirmed the predicted sequence of the R and M sites, with the M site sequence being nonconsensual: M(P3)-N(P2)-A(P1)/S(P1'). Mutagenesis and expression kinetics studies suggested that the atypical MDV M site was cleaved exclusively by the processed short protease, a feature making MDV unique among herpesviruses.

Inheritance of arterial lesions in renal fibromuscular dysplasia

We have previously shown that patients with renal fibromuscular dysplasia (FMD) have asymptomatic carotid lesions and that familial forms may occur. The objective of this study was to test whether carotid lesions could be detected in relatives of familial cases. High-resolution echotracking of the carotid artery was performed in 47 relatives of 13 cases from six families. This non-invasive investigation led to a semiquantitative arterial score that was compared with that obtained for 47 controls matched for age and sex and that for 125 sporadic cases. Familial resemblance was tested by using a generalized estimating equation approach taking into account the clustering of scores in families. As expected, FMD cases had a significantly higher score than controls (4.02 vs 2.52, P<10(-5)). Familial cases were not significantly different from sporadic cases. Of interest, the 47 apparently healthy relatives of familial cases had also a high carotid score (4.17), very significantly higher than that of controls (2.52, P<10(-5)) even though lower than the corresponding index FMD cases (4.81, P=0.01). Segregation analysis showed that 52% of the descendants of subjects with a score >4 had a score >4, a proportion consistent with autosomal-dominant transmission of the trait. Altogether these results strengthen the hypothesis of renal FMD being a systemic arterial disease and argue for a familial resemblance that may be due to a major genetic effect. The carotid score obtained by high-resolution echotracking may provide a non-invasive surrogate marker for renal FMD of potential value for use in linkage strategies on large pedigrees.

A glycosylated complex of gadolinium, a new potential contrast agent for magnetic resonance angiography?

A new low-molecular weight dendrimer-like MRI contrast agent (Gd-D1) has been synthesized and characterized in vitro by proton and oxygen-17 relaxometry. Its pharmacokinetic parameters and biodistribution patterns were evaluated on rats. Its in vitro and in vivo properties, that is, the longitudinal relaxivity (defined as the increase of the water proton longitudinal relaxation rate induced by one millimole per liter of Gd-D1) equal to 5.6s(-1)mM(-1) at 20 MHz and 310 K, the elimination half-time equal to 85 min, and its low accumulation in liver and spleen, underline its potential as a blood-pool MRI contrast agent.

Phase I/II study of preoperative cetuximab, capecitabine, and external beam radiotherapy in patients with rectal cancer

BACKGROUND

To assess the safety and preliminary efficacy of concurrent radiotherapy, capecitabine, and cetuximab in the preoperative treatment of patients with rectal cancer.

PATIENTS AND METHODS

Forty patients with rectal cancer (T3-T4, and/or N+, endorectal ultrasound) received preoperative radiotherapy (1.8 Gy, 5 days/week for 5 weeks, total dose 45 Gy, three-dimensional conformal technique) in combination with cetuximab [initial dose 400 mg/m(2) intravenous given 1 week before the beginning of radiation followed by 250 mg/m(2)/week for 5 weeks] and capecitabine for the duration of radiotherapy (650 mg/m(2) orally twice daily, first dose level; 825 mg/m(2) twice daily, second dose level).

RESULTS

Four and six patients were treated at the first and second dose level of capecitabine, respectively. No dose-limiting toxicity occurred. Thirty additional patients were treated with capecitabine at 825 mg/m(2) twice daily. The most frequent grade 1/2 side-effects were acneiform rash (87%), diarrhea (65%), and fatigue (57%). Grade 3 diarrhea was found in 15%. Three grade 4 toxic effects were recorded: one myocardial infarction, one pulmonary embolism, and one pulmonary infection with sepsis. Two patients (5%) had a pathological complete response.

CONCLUSIONS

Preoperative radiotherapy in combination with capecitabine and cetuximab is feasible with some patients achieving pathological downstaging.

Major rearrangements in the E element and minor variations in the U3 sequences of the avian leukosis subgroup J provirus isolated from field myelocytomatosis

We collected paraffin-embedded myelocytomatoses induced by subgroup J avian leukosis virus (ALV-J) in French poultry from 1992 to 2000. We used nested PCR to obtain the U3 LTR and the E element sequences that encompass putative binding sites for transcription factors. We observed minor mutations in the U3 sequences that rarely affected transcription factor binding sites, thus preserving the transcriptional potential of the U3 LTR. However, we observed a large variability in the E element sequences from both field and experimental tumor samples. This variability involved genomic rearrangements and various deletions that most often occurred between two direct repeat sequences. Moreover, in seven DNA samples of the 22 field tumors analyzed, we observed two different sequences for the E element region, suggesting that proviral genomes of two different sizes may be simultaneously present in a tumor. Even though most of the E element sequences were mutated or rearranged, all myelocytomatosis samples always exhibited one E element sequence containing at least one putative C/EBP binding site that was unaffected and still potentially functional.

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for colorectal peritoneal carcinomatosis: higher complication rate for oxaliplatin compared to Mitomycin C

BACKGROUND

Peritoneal carcinomatosis (PC) from colo-rectal cancer carries a very poor prognosis with a mean and median overall survival times of 6.9 and 5.2 months. It has been proved that a locoregional therapeutic approach of this disease with cytoreduction followed by hyperthermic intraperitoneal chemotherapy (HIPEC) improved survival of these patients. However, this combined treatment presents a high complication rate.

METHODS

21 patients with PC of colorectal origin underwent complete cytoreduction followed by HIPEC using Mitomycin-C (13 patients) or oxaliplatin (8 patients) and the open coliseum technique. For each case the medical datas were retrospectively analysed to determine feasibility, morbidity, mortality, survival time and prognostic factors.

RESULTS

All patients presented a Sugarbaker's Peritoneal Cancer index inferior to 15. The mean operating time was 453 minutes. After a median follow-up of 24.9 months, actuarial disease-free survival was 36.6% at 5 years. The median survival time was 34 months. The morbidity rate was 33.3% with a significant higher complication rate in the oxaliplatin group (5/8) than in the Mytomycin-C (MMC) group (2/13). One patient (4.7%) died two months after treatment with MMC (endocarditis).

CONCLUSIONS

This series confirm positive impact of cytoreduction and HIPEC on PC. We obtained a moderated complications rate thanks to a high degree of selection of the patient. Oxaliplatin scheme is responsible of a higher morbidity than in MMC group. Phase III trial comparing these two drugs is needed.

Molecular epidemiology of European brown hare syndrome virus in France between 1989 and 2003

Genetic diversity between French European brown hare syndrome (EBHS) viruses since the disease appeared has been evaluated. Nucleotide sequencing of the partial capsid protein genes of 169 EBHS viruses collected from various parts of France between 1989 and 2003, three reference strains, and a Greek EBHSV collected in 2002 revealed a maximum nucleotide divergence of 11.7%, indicating a high level of conservation between viruses. Two major groups were identified. The first group contained EBHS viruses collected since 1989 from different parts of France, the reference strains, and all of the viruses located in the far north of France. In this group, three genogroups were clearly identified as mainly related to their geographic origin. The distribution of the viruses suggests that the early viruses have not disappeared and have slowly evolved in their area of origin. The second group, supported by a significant bootstrap value, contained the Greek EBHSV with the French EBHS viruses collected between 1999 and 2003 from regions of southern France. It constitutes a newly identified genogroup. Our results demonstrate strong differences in genetic evolution between EBHSV and rabbit haemorrhagic disease virus, with persistence of the earlier EBHS viruses and interaction between the geographical and temporal distributions.

Arterial stiffness and enlargement in mild-to-moderate chronic kidney disease

Chronic kidney disease (CKD) is associated with an increased risk of cardiovascular morbidity and mortality. Arterial stiffness and remodeling have been well documented in patients with end-stage renal disease, but little is known about arterial phenotype in CKD patients with moderate reduction in glomerular filtration rate (GFR). In total, 95 patients (58+/-15 years, mean+/-s.d.) with CKD and GFR measured by renal clearance of (51)Cr-ethylenediaminetetraacetate were compared to 121 hypertensive patients without CKD (59+/-11 years), and 57 normotensive subjects (56+/-6 years). Common carotid artery diameter, intima-media thickness (IMT), distensibility, and Young's elastic modulus were noninvasively determined with a high-definition echotracking system. Patients with CKD had a significantly larger carotid internal diameter than in hypertensives and normotensives (6.32+/-1.05, 5.84+/-0.74, and 5.50+/-0.64 m x 10(-3), respectively; P<0.001), resulting in 25% and 11% increases in circumferential wall stress, respectively, since no significant difference in IMT was observed. Carotid distensibility and elastic modulus did not significantly differ between CKD and hypertensives; normotensives had significantly higher distensibility and lower elastic modulus than CKD and hypertensive patients. Carotid-femoral pulse wave velocity was significantly higher in CKD patients than in hypertensives and normotensives. In multivariate analyses either involving the entire population or restricted to CKD patients, GFR was independently and strongly related to carotid diameter and elastic modulus. Arterial enlargement and increased arterial stiffness occur in parallel with the decline in renal function in patients with mild-to-moderate CKD.

Autism spectrum disorders associated with X chromosome markers in French-Canadian males

It is now well established that genetic factors play an important role in the pathogenesis of autism disorder and converging lines of evidence suggest the implication of the X chromosome. Using a sample of subjects diagnosed with autism spectrum disorders, exclusively composed of males from French-Canadian (FC) origin, we tested markers covering the entire X chromosome using a family-based association study. Our initial analysis revealed the presence of association at two loci: DXS6789 (P=0.026) and DXS8043 (P=0.0101). In a second step, we added support to the association at DXS8043 using additional markers, additional subjects and a haplotype-based analysis (best obtained P-value=0.00001). These results provide support for the existence of a locus on the X chromosome that predisposes the FC to autism spectrum disorders.

Phase II study of preoperative oxaliplatin, capecitabine and external beam radiotherapy in patients with rectal cancer: the RadiOxCape study

BACKGROUND

Preoperative radiotherapy has been shown to decrease the local recurrence rate of patients with locally advanced rectal cancer. Capecitabine and oxaliplatin are both active anticancer agents in the treatment of patients with advanced colorectal cancer and have radiosensitizing properties. Therefore, these drugs would be expected to improve effectiveness of preoperative radiotherapy in terms of local control and prevention of distant metastases.

PATIENTS AND METHODS

Forty patients with rectal cancer (T3-T4 and/or N+) received radiotherapy (1.8 Gy, 5 days a week over 5 weeks, total dose 45 Gy, 3D conformational technique) in combination with intravenous oxaliplatin 50 mg/m2 once weekly for 5 weeks and oral capecitabine 825 mg/m2 twice daily on each day of radiation. Surgery was performed 6-8 weeks after completion of radiotherapy. The main end points were safety and efficacy as assessed by the pathological complete response (pCR).

RESULTS

The most frequent grade 3/4 adverse event was diarrhea, occurring in 30% of patients. pCR was found in five (14%) patients. According to Dworak's classification, good regression was found in six (18%) additional patients.

CONCLUSIONS

Combination of preoperative radiotherapy with capecitabine and oxaliplatin is feasible for downstaging rectal cancer.

[Tympanic paragangliomas: analysis of a nine cases]

OBJECTIVE

The purpose of this work was to evaluate the diagnostic strategy and outcome of patients treated for tympanic paraganglioma.

PATIENTS AND METHODS

Nine patients presented with tympanic paraganglioma were treated in our unit from 1996 to 2003. There were eight women and one man, mean age 65 years. Surgery was performed in all nine patients. This retrospective analysis focused on revealing signs, diagnostic tools, surgical procedure for tumor resection, and short-, mid-, and long-term functional outcome.

RESULTS

The surgical procedure was well tolerated by all patients. There were no cases of postoperative mastoiditis. None of the patients experienced postoperative dizziness. Total tumor removal was achieved in seven patients. In one patient, incomplete tumor resection was decided in order to preserve facial motion. All patients but one were relieved from their tinnitus in the early postoperative period. In four patients, preoperative hearing levels were worsened by the surgical procedure, essentially through an alteration of preoperative conductive hearing loss.

CONCLUSION

MRI is highly contributive to the diagnosis of tympanic paraganglioma, which should be evoked in patients with pulsatile tinnitus. Diagnosis should be established as early as possible to lower the postoperative morbidity. While surgery can provide cure and relieve tinnitus, there is a high risk of auditory deterioration.

Electrical control of hole spin relaxation in charge tunable InAs/GaAs quantum dots

We report on optical orientation of singly charged excitons (trions) in charge-tunable self-assembled InAs/GaAs quantum dots. When the charge varies from 0 to -2, the trion photoluminescence of a single quantum dot shows up and under quasiresonant excitation gets progressively polarized from zero to approximately 100%. This behavior is interpreted as the electric control of the trion thermalization process, which subsequently acts on the hole-spin relaxation driven in nanosecond time scale by the anisotropic electron-hole exchange. This is supported by the excitation spectroscopy and time-resolved measurements of a quantum dot ensemble.

A patient who survived total colonic ulcerative colitis surinfected by cytomegalovirus complicated by toxic megacolon and disseminated intravascular coagulation

The authors report the case of a patient aged 60-year-old who survived ulcerative colitis complicated by toxic megacolon and disseminated intravascular coagulation. This patient was not known for this ulcerative colitis and was first hospitalised for a suspicion of diverticulitis. The admission symptoms were fever, abdominal pain and bloody diarrhoea. The evolution was defavorable under antibiotics and sulfasalazine. The patient was readmitted 5 days after he left hospital, and the diagnosis of UC was based on colon biopsy made during the first hospitalisation. A treatment with methylprednisolone was started and the patient worsened day by day with apparition of toxic megacolon and disseminated intravascular coagulation. Subtotal colectomy was performed for degradation of general status and coagulation factors. Pathological findings confirmed ulcerative colitis with toxic megacolon. Cytomegalovirus inclusions were demonstrated on the colonic specimen and confirmed by PCR. In this report the authors discuss the etiology of toxic megacolon and disseminated intravascular coagulation in ulcerative colitis surinfected by cytomegalovirus. Mortality of these pathologies is high necessitating rapid diagnosis of cytomegalovirus infection by sigmoid biopsy. Management requires immunosupression interruption and ganciclovir therapy, or surgery in unsuccessful medical treatment.

Report on the Belgian consensus meeting on colorectal cancer screening

Screening and prevention of colorectal cancer must be a public health priority. It is the most frequent malignancy in Europe, the second leading cause of cancer death, including Belgium where more than 6000 new cases occur per year. Various screening modalities, from non invasive to invasive are available and currently in use and they are all cost-effective in comparison with no screening. The decision as to which screening test to use should be made by the patient and clinician. Consensus documents prepared by the Belgian scientific community appear in this issue of Acta Gastroenterologica Belgica, summarizing the scientific evidence in favour as well as the limitations of fecal occult blood tests, flexible sigmoidoscopy, videocolonoscopy and virtual colonoscopy.

Molecular events associated with accelerated proliferative response in rat livers when partial hepatectomy is preceded by a sham operation

BACKGROUND

When a sham operation is performed 6 h before partial hepatectomy (PH), the regenerative response is accelerated suggesting that sham operation itself contributes to cellular events leading to proliferation.

MATERIALS AND METHODS

In order to examine the mechanisms implicated in this acceleration, we compared the activation of several factors associated with the progression through the cell cycle at various times after PH and after PH preceded by sham operation (S6 h + PH). The effect of a single sham (S) and two combined sham operations (S6 h + S) was also examined. Nonoperated rats were used as controls (C).

RESULTS

The early factors NF-kappaB and Stat3 were activated after S6 h + PH and S6 h + S. C-jun expression was increased 0.5 h and 2 h after PH and 6 h after sham. There was no further increase in S6 h + PH and S6 h + S. In contrast, c-myc expression returned to baseline levels after S6 h and a new increase was observed 2 h after S6 h + PH but not after S6 h + S. P53 mRNA was significantly expressed 6 h after S6 h + PH, but at a level similar than that observed 6 and 12 h after PH alone. An earlier increase in c-Ha-ras mRNA and cyclin E protein was found in S6 h + PH, in comparison with PH alone.

CONCLUSIONS

The first divergent response between the two combined models involved c-myc expression. However, major differences related to the accelerated liver regenerative response observed after S6 h + PH were found at late time points associating an earlier expression of c-Ha-ras and nuclear cyclin E.