Optimal conditions for flexible methane production in a demand-based operation of biogas plants

The aim of the presented work was to study the methane production limits and to determine optimal conditions for flexible operation of an anaerobic reactor in order to set up an operational strategy. Punctual overloads were conducted in a laboratory-scale anaerobic reactor with readily biodegradable solid substrates, and the influences of overload intensity, baseload value and substrate used were investigated. A maximal daily value around 1000mL/L of reactor for methane production has been assessed. This value did not evolve significantly during experiment time, and conditioned the persistence of overloads as well as the flexibility margin on the reactor, which ranged from +25% to +140% on daily production. Results highlighted the fact that for a maximum flexibility, low organic loading rates are better to work with on this type of reactors.

Disorders of Microtubule Function in Neurons: Imaging Correlates

BACKGROUND AND PURPOSE

A number of recent studies have described malformations of cortical development with mutations of components of microtubules and microtubule-associated proteins. Despite examinations of a large number of MRIs, good phenotype-genotype correlations have been elusive. Additionally, most of these studies focused exclusively on cerebral cortical findings. The purpose of this study was to characterize imaging findings associated with disorders of microtubule function.

MATERIALS AND METHODS

MRIs from 18 patients with confirmed tubulin mutations (8 TUBA1A, 5 TUBB2B, and 5 TUBB3) and 15 patients with known mutations of the genes encoding microtubule-associated proteins (5 LIS1, 4 DCX, and 6 DYNC1H1) were carefully visually analyzed and compared. Specific note was made of the cortical gyral pattern, basal ganglia, and white matter to assess internal capsular size, cortical thickness, ventricular and cisternal size, and the size and contours of the brain stem, cerebellar hemispheres and vermis, and the corpus callosum of patients with tubulin and microtubule-associated protein gene mutations. Results were determined by unanimous consensus of the authors.

RESULTS

All patients had abnormal findings on MR imaging. A large number of patients with tubulin gene mutations were found to have multiple cortical and subcortical abnormalities, including microcephaly, ventriculomegaly, abnormal gyral and sulcal patterns (termed "dysgyria"), a small or absent corpus callosum, and a small pons. All patients with microtubule-associated protein mutations also had abnormal cerebral cortices (predominantly pachygyria and agyria), but fewer subcortical abnormalities were noted.

CONCLUSIONS

Comparison of MRIs from patients with known mutations of tubulin genes and microtubule-associated proteins allows the establishment of some early correlations of phenotype with genotype and may assist in identification and diagnosis of these rare disorders.

[Human papilloma virus in head and neck cancer]

Head and neck cancer is frequently associated with alcohol and tobacco consumption but there is an increasing incidence of oropharyngeal carcinoma associated with oncogenic type-16 human papillomavirus (HPV). The clinical profile of these patients is distinct from that of other patients, with an earlier onset, 1/1 male to female sex ratio, cystic cervical nodes. Detection of intratumoral viral DNA is essential to confirm the role of HPV. According to several reports, the prognosis in terms of survival and locoregional control is better in HPV-positive oropharyngeal carcinoma than in HPV-negative oropharyngeal carcinoma or associated with tobacco consumption. The future lies in vaccination of women against cervical cancer but vaccination of boys will be certainly necessary.

SLC25A22 is a novel gene for migrating partial seizures in infancy

OBJECTIVE

To identify a genetic cause for migrating partial seizures in infancy (MPSI).

METHODS

We characterized a consanguineous pedigree with MPSI and obtained DNA from affected and unaffected family members. We analyzed single nucleotide polymorphism 500K data to identify regions with evidence of linkage. We performed whole exome sequencing and analyzed homozygous variants in regions of linkage to identify a candidate gene and performed functional studies of the candidate gene SLC25A22.

RESULTS

In a consanguineous pedigree with 2 individuals with MPSI, we identified 2 regions of linkage, chromosome 4p16.1-p16.3 and chromosome 11p15.4-pter. Using whole exome sequencing, we identified 8 novel homozygous variants in genes in these regions. Only 1 variant, SLC25A22 c.G328C, results in a change of a highly conserved amino acid (p.G110R) and was not present in control samples. SLC25A22 encodes a glutamate transporter with strong expression in the developing brain. We show that the specific G110R mutation, located in a transmembrane domain of the protein, disrupts mitochondrial glutamate transport.

INTERPRETATION

We have shown that MPSI can be inherited and have identified a novel homozygous mutation in SLC25A22 in the affected individuals. Our data strongly suggest that SLC25A22 is responsible for MPSI, a severe condition with few known etiologies. We have demonstrated that a combination of linkage analysis and whole exome sequencing can be used for disease gene discovery. Finally, as SLC25A22 had been implicated in the distinct syndrome of neonatal epilepsy with suppression bursts on electroencephalogram, we have expanded the phenotypic spectrum associated with SLC25A22.

G-protein coupled receptor 56 promotes myoblast fusion through serum response factor- and nuclear factor of activated T-cell-mediated signalling but is not essential for muscle development in vivo

Mammalian muscle cell differentiation is a complex process of multiple steps for which many of the factors involved have not yet been defined. In a screen to identify the regulators of myogenic cell fusion, we found that the gene for G-protein coupled receptor 56 (GPR56) was transiently up-regulated during the early fusion of human myoblasts. Human mutations in the gene for GPR56 cause the disease bilateral frontoparietal polymicrogyria; however, the consequences of receptor dysfunction on muscle development have not been explored. Using knockout mice, we defined the role of GPR56 in skeletal muscle. GPR56(-/-) myoblasts have decreased fusion and smaller myotube sizes in culture. In addition, a loss of GPR56 expression in muscle cells results in decreases or delays in the expression of myogenic differentiation 1, myogenin and nuclear factor of activated T-cell (NFAT)c2. Our data suggest that these abnormalities result from decreased GPR56-mediated serum response element and NFAT signalling. Despite these changes, no overt differences in phenotype were identified in the muscle of GPR56 knockout mice, which presented only a mild but statistically significant elevation of serum creatine kinase compared to wild-type. In agreement with these findings, clinical data from 13 bilateral frontoparietal polymicrogyria patients revealed mild serum creatine kinase increase in only two patients. In summary, targeted disruption of GPR56 in mice results in myoblast abnormalities. The absence of a severe muscle phenotype in GPR56 knockout mice and human patients suggests that other factors may compensate for the lack of this G-protein coupled receptor during muscle development and that the motor delay observed in these patients is likely not a result of primary muscle abnormalities.

[Target volumes in cervical lympadenopathies of unknown primary: toward a selective customized approach? On behalf of REFCOR]

The treatment of carcinomas of unknown primary revealed by cervical lymphadenopathy is based on neck dissection and nodal and pan-mucosal irradiation to control the neck and avoid the emergence of a metachronous primary. The aim of this review was to assess diagnostic and therapeutic approaches and criteria that may be used for a customized selective approach to avoid severe toxicities of pan-mucosal irradiation. A literature search was performed with the following keywords: cervical lymphadenopathy, unknown primary, upper aerodigestive tract, cancer, radiotherapy, squamous cell carcinoma, variants. The diagnostic workup includes a head and neck scanner or MRI, ((18)F)-FDG PET CT, a panendoscopy and tonsillectomy. Squamous cell carcinoma represents over two thirds of cases. The number of metastatic cervical nodes, nodal level, and histological variant (associated with HPV/EBV status) may determine the primary site origin and might be weighted for the determination of radiation target volumes on a multidisciplinary basis. A selective customized approach is relevant to decrease radiation toxicity only if neck and mucosal control is not impaired. Although no recommendation can yet be made in the absence of sufficient level of evidence, the relevance of systematic pan-mucosal irradiation appears questionable in a number of clinical situations. Accordingly, a customized selective redefinition of target volumes may be discussed and be prospectively evaluated in relation to the therapeutic index obtained.

Schizencephaly: association with young maternal age, alcohol use, and lack of prenatal care

Schizencephaly is a rare malformation of cortical development characterized by congenital clefts extending from the pial surface to the lateral ventricle that are lined by heterotopic gray matter. The clinical presentation is variable and can include motor or cognitive impairment and epilepsy. The causes of schizencephaly are heterogeneous and can include teratogens, prenatal infection, or maternal trauma. Reported genetic causes include chromosomal aneuploidy, EMX2 mutations, and possible autosomal recessive familial cases based on recurrence in siblings. In an effort to identify risk factors for schizencephaly, we conducted a survey of 48 parents or primary caretakers of patients with schizencephaly born between 1983 and 2004. We discovered that young maternal age, lack of prenatal care, and alcohol use were all significantly associated with risk of schizencephaly. Our results suggest that there are important nongenetic, intrauterine events that predispose to schizencephaly.

Initial staging of squamous cell carcinoma of the oral cavity, larynx and pharynx (excluding nasopharynx). Part I: Locoregional extension assessment: 2012 SFORL guidelines

OBJECTIVES

To set out good practice guidelines for locoregional extension assessment of squamous cell carcinoma of the head and neck (excluding nasopharynx, nasal cavities and sinuses).

MATERIALS AND METHODS

A critical multidisciplinary review of the literature on locoregional extension assessment of squamous cell carcinoma of the head and neck was conducted, applying levels of evidence in line with the French health authority's (HAS) literature analysis guide of January 2000.

CONCLUSION

Based on the levels of evidence of the selected articles and on work-group consensus, graded guidelines are set out for clinical, endoscopic and imaging locoregional extension assessment of head and neck cancer.

Initial staging for squamous cell carcinoma of the mouth, larynx and pharynx (except nasopharynx). Part 3: general assessment. 2012 SFORL recommendations

OBJECTIVES

The French Society of Otorhinolaryngology (SFORL) set up a work group to draw up guidelines for initial staging of head and neck squamous cell carcinoma. Locoregional and remote extension assessment are dealt with in two separate reports. The present part 3 deals with the assessment of frequent associated symptoms and pathologies, requiring early treatment and the collection of data on a certain number of clinical and paraclinical parameters for therapeutic decision-making in the multidisciplinary team meeting.

MATERIALS AND METHODS

A multidisciplinary critical analysis of the literature was conducted. General assessment here covers screening, assessment and initial management of the following: usual risk factors (smoking, alcohol, HPV), the most frequent medical comorbidities, nutritional status, social and psychological status, dental status, pain and possible anemia. As oncologic management frequently associates surgery, radiation therapy and chemotherapy, the underlying examinations should be early, as part of initial staging. The levels of evidence for the examinations were estimated so as to grade guidelines, failing which expert consensuses were established.

RESULTS

The high rates of pain, malnutrition and anemia call for systematic screening and early management, especially as rapidly effective treatments exist. Assessing comorbidity and social and psychological status enables general health status to be assessed, along with possible contraindications to the usual treatments. Tracheal intubation problems may require intubation under flexible endoscopy or jet-ventilation by inter-cricothyroid catheterization from the diagnostic endoscopy stage. Assessment and adapted dental care should be conducted if radiation therapy is likely or certain.

CONCLUSION

Early management of symptoms and comorbidity and anticipation of subsequent treatment are intended to shorten initial staging time and to collate the data needed for therapeutic decision-making. This assessment should be performed at the same time as the locoregional and remote extension assessment, and is obviously to be adapted according to tumoral extension stage and the possible treatment options.

Location of periventricular nodular heterotopia is related to the malformation phenotype on MRI

BACKGROUND AND PURPOSE

Periventricular nodular heterotopia are common malformations of cortical development that are associated with many clinical syndromes and with many different neuroimaging phenotypes. The purpose of this study was to determine whether specific malformation phenotypes may be related to location, side, or number of PNH as assessed by MR imaging.

MATERIALS AND METHODS

MR images of 200 patients previously diagnosed with PNH were retrospectively analyzed. PNH were classified according to their location along the ventricles (anterior, posterior, or diffuse), side (unilateral or bilateral), and number of nodules (<5, 6-10, or >10). The cerebrum, brain stem and cerebellum were analyzed to assess associated anomalies. Associations between PNH location and the presence of other anomalies were tested by using Fisher exact test and χ2 test.

RESULTS

Posterior PNH were significantly associated with malformations of the cerebral cortex, diminished white matter volume, and mid-/hindbrain anomalies. Diffuse PNH were associated with diminished white matter volume, callosal "anomalies," and the presence of megacisterna magna. Unilateral PNH were strongly associated with cortical malformations.

CONCLUSIONS

Certain malformation complexes are associated with PNH in specific locations: posterior PNH with cerebral cortical and mid-/hindbrain malformations and diffuse PNH with callosal anomalies and megacisterna magna. Knowledge of these associations should allow more directed analyses of brain MR imaging in patients with PNH. In addition, knowledge of these associations may help to direct studies to elucidate the causes of these malformation complexes.

Laparoscopic extraperitoneal colostomy in elective abdominoperineal resection for cancer: a single surgeon experience

AIM

Parastomal herniation of end colostomies can be chronically debilitating for patients and a difficult problem to treat. To prevent parastomal hernia (PSH) formation an extraperitoneal colostomy (EPC) approach has been developed in open colorectal surgery and some studies have suggested a potential advantage to this approach. Here we describe our technique of laparoscopic extraperitoneal stoma formation and present our experience to date.

METHODS

We performed a retrospective analysis of consecutive patients undergoing a laparoscopic abdominoperineal resection between March 1999 and March 2011. We performed the EPC technique as follows: under laparoscopic guidance, a smooth tip instrument was used to gently separate the peritoneum from the posterior aponeurotic plane to create an extraperitoneal tunnel running from the skin incision to the left flank of the abdominal cavity to join the previously dissected paracolic gutter. The colon was exteriorized and the position was checked to ensure the absence of torsion or kinking.

RESULTS

Twenty-two patients underwent a standard laparoscopic abdominoperineal resection with total mesorectal excision. Colostomy was constructed extraperitoneally (EPC) or transperitoneally (TPC) in 12 and 10 patients respectively. There were five complications requiring operative intervention: two stomal necrosis and one surgical site infection in the TPC group and two small bowel occlusions in the EPC group. Four patients from the TPC group developed PSH at 24, 36, 48 and 72 months respectively while there were no cases of PSH in the EPC group.

CONCLUSION

Extraperitoneal laparoscopic colostomy showed a potential reduction of PSH in our series of patients.

[Auditory and vestibular findings in Fabry disease: a study of 25 patients]

PURPOSE

Fabry disease (FD, OMIM 301500) is an X-linked lysosomal storage disorder due to deficient activity of the enzyme alpha-galactosidase A. Males and females exhibit severe organ involvement. The high incidence of otological symptoms was recently reported.

PATIENTS AND METHODS

Monocentric and retrospective study of twenty-five patients with FD (13 families; seven males and 18 females). The patients underwent audiological assessment before initiation and during enzyme replacement therapy. We also analysed neurologic heart and kidney status.

RESULTS

Twenty patients (80%; 13 females and seven males) complained of otologic symptoms. Audiological evaluation showed a sensorineural hearing loss in 17 patients, bilateral in 16 out of them. Vestibular examination showed a functional impairment in two patients (one female, one male). Correlations were found between hearing loss and either kidney disease (73,3%), neurological complications (100%) and cardiomyopathy (80%). Fourteen patients (56%; seven females, seven males) received enzyme replacement therapy. Improvement or stabilization of the audiological evaluation was reported in seven patients, whereas worsening was observed in three patients.

CONCLUSION

This study confirms the high frequency of audiological involvements in females and males with FD. Our analysis suggests that the frequency of hearing loss is increased in the presence of renal or neurologic involvement or cardiomyopathy. There is no clinically significant efficacy of enzyme replacement therapy on hearing function. Although the pathophysiology remains unknown, a vascular mechanism responsible of the inner ear involvement seems to be privileged.

FLNA genomic rearrangements cause periventricular nodular heterotopia

OBJECTIVE

To identify copy number variant (CNV) causes of periventricular nodular heterotopia (PNH) in patients for whom FLNA sequencing is negative.

METHODS

Screening of 35 patients from 33 pedigrees on an Affymetrix 6.0 microarray led to the identification of one individual bearing a CNV that disrupted FLNA. FLNA-disrupting CNVs were also isolated in 2 other individuals by multiplex ligation probe amplification. These 3 cases were further characterized by high-resolution oligo array comparative genomic hybridization (CGH), and the precise junctional breakpoints of the rearrangements were identified by PCR amplification and sequencing.

RESULTS

We report 3 cases of PNH caused by nonrecurrent genomic rearrangements that disrupt one copy of FLNA. The first individual carried a 113-kb deletion that removes all but the first exon of FLNA. A second patient harbored a complex rearrangement including a deletion of the 3' end of FLNA accompanied by a partial duplication event. A third patient bore a 39-kb deletion encompassing all of FLNA and the neighboring gene EMD. High-resolution oligo array CGH of the FLNA locus suggests distinct molecular mechanisms for each of these rearrangements, and implicates nearby low copy repeats in their pathogenesis.

CONCLUSIONS

These results demonstrate that FLNA is prone to pathogenic rearrangements, and highlight the importance of screening for CNVs in individuals with PNH lacking FLNA point mutations.