A founder mutation in BBS2 is responsible for Bardet‐Biedl syndrome in the Hutterite population: utility of SNP arrays in genetically heterogeneous disorders

Innes AM, Boycott KM, Puffenberger EG, Redl D, MacDonald IM, Chudley AE, Beaulieu C, Perrier R, Gillan T, Wade A, Parboosingh JS. A founder mutation in BBS2 is responsible for Bardet‐Biedl syndrome in the Hutterite population: utility of SNP arrays in genetically heterogeneous disorders. Bardet‐Biedl syndrome (BBS) is a multisystem genetically heterogeneous disorder, the clinical features of which are largely the consequence of ciliary dysfunction. BBS is typically inherited in an autosomal recessive fashion, and mutations in at least 14 genes have been identified. Here, we report the identification of a founder mutation in the BBS2 gene as the cause for the increased incidence of this developmental disorder in the Hutterite population. To ascertain the Hutterite BBS locus, we performed a genome‐wide single nucleotide polymorphism (SNP) analysis on a single patient and his three unaffected siblings from a Hutterite family. The analysis identified two large SNP blocks that were homozygous in the patient but not in his unaffected siblings, one of these regions contained the BBS2 gene. Sequence analysis and subsequent RNA studies identified and confirmed a novel splice site mutation, c.472‐2A>G, in BBS2. This mutation was also found in homozygous form in three subsequently studied Hutterite BBS patients from two different leuts, confirming that this is a founder mutation in the Hutterite population. Further studies are required to determine the frequency of this mutation and its role, if any, in the expression of other ciliopathies in this population.     

Bovine lactoferricin induces caspase-independent apoptosis in human B-lymphoma cells and extends the survival of immune-deficient mice bearing B-lymphoma xenografts

Although current treatments based on the use of B-cell-specific anti-CD20 monoclonal antibodies and aggressive combinatorial chemotherapy have improved the survival of patients suffering from B-cell non-Hodgkin's lymphoma (NHL), some individuals fail to respond to treatment and relapses remain common. New and more effective treatments for B-cell NHL are therefore required. Bovine lactoferricin (LfcinB) is a cationic antimicrobial peptide that is cytotoxic for several human tumor cell lines but does not harm healthy cells. Here we show that in vitro treatment with LfcinB caused Raji and Ramos human B-lymphoma cells to die by apoptosis, as indicated by DNA fragmentation, chromatin condensation, and nuclear disintegration. LfcinB killed B-lymphoma cells more efficiently at low serum concentrations and was inhibited in the presence of exogenous bovine serum albumin, suggesting partial neutralization of cationic LfcinB by anionic serum components. LfcinB-induced apoptosis in B-lymphoma cells was caspase-independent since caspase-3 activation was not detected by Western blotting and the general caspase inhibitor z-VAD-fmk did not prevent LfcinB-induced DNA fragmentation. Importantly, immune-deficient SCID/beige mice that were inoculated intravenously with Ramos B-lymphoma cells in order to model B-cell NHL exhibited extended survival following systemic administration of LfcinB, indicating that LfcinB warrants further investigation as a novel therapeutic agent for the possible treatment of B-cell NHL.     

Polyhydroxymethylenes as Multifunctional High Molecular Weight Sugar Alcohols Tailored for 3D Printing and Medical Applications

Common sugar alcohols used as artificial sweeteners and components of polymer networks represent low molecular weight polyhydroxymethylenes (PHMs) with the general formula [CH(OH)]_nH₂ but very low degree of polymerization (n = 2–6). Herein high molecular weight PHM (n >> 100) unparalleled in nature is tailored for 3D printing and medical applications by free radical polymerization of 1,3‐dioxol‐2‐one vinylene carbonate to produce polyvinylene carbonate (PVCA) which yields PHM by hydrolysis. Furthermore, PVCA is solution processable and enables PHM functionalization, membrane formation, and extrusion‐based 3D printing. Opposite to cellulose, amorphous PHM is plasticized by water and is readily functionalized via PVCA aminolysis/hydrolysis to produce polyhydroxymethylene urethane (PHMU), enable PHM crosslinking and coupling of PHM with amine‐functional components like gelatin. After hydrolysis/aminolysis the original PVCA shapes are retained. PVCA solution casting yields PVCA and PHM which exhibits uniform and hierarchic pore architectures. Asymmetric membranes, hydrogels, PHM/collagen blends, and electrospun nonwovens of PVCA, PHM, and PHMU are readily tailored for medical applications. 3D printing of PVCA dispersions containing hydroxyapatite affords porous PVCA, PHMU, and PHM scaffolds useful in regenerative medicine. PHM and functionalized PHMs as carbohydrate‐inspired multifunctional materials indicate in vitro biocompatibility and hold great promise for applications in medicine and health care.     

Basic anatomical investigation of semitendinosus and the long head of biceps femoris muscle for their possible use in electrically stimulated neosphincter formation

Summary Anal neosphincter formation with electrically stimulated gracilis muscle is used increasingly for the surgical treatment of fecal incontinence. An alternative to gracilis might be of interest if this muscle is not available. 30 semitendinosus muscles and 15 long heads of biceps femoris were investigated on human cadavers. In particular, the nerve and vascular supply of these muscles was studied, both representing basic factors for muscle transposition. The long head of biceps femoris m. was found to receive its dominant vascular supply from the first and second perforating artery and its nerve supply from one motor branch out of the sciatic nerve, both as described in literature. The examination of semitendinosus m., however, revealed new anatomical aspects in its vascular supply. In all cases semitendinosus m. was found to receive dominant vascular pedicles from the medial circumflex femoral artery close to the ischial tuberosity and the second perforating artery. The nerve supply consisted of two motor branches out of the sciatic nerve. Both muscles fulfilled several basic criterias for transposition to the anus. However, regarding these requirements, semitendinosus offered distinct advantages in comparison with the long head of biceps femoris. Due to its vascular and nerve topography, semitendinosus seems suitable to serve as an alternative to gracilis.

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Bases anatomiques de l'utilisation du muscle semitendineux et du chef long du biceps fémoral comme néosphincter anal électro-stimulé

Résumé La graciloplastie électro-stimulée est utilisée de plus en plus fréquemment dans le traitement chirurgical de l'incontinence anale. L'utilisation d'un autre muscle peut être intéressante si le muscle gracile n'est pas utilisable. 30 muscles semitendineux et 15 longs chefs du biceps fémoral ont été étudiés sur des cadavres humains. Ce travail a porté particulièrement sur l'innervation et la vascularisation de ces muscles, dont dépendent les possibilités de transposition. Le long chef du m. biceps fémoral recevait sa vascularisation principale de la première et de la deuxième artère perforante et son innervation d'une branche motrice venant du nerf sciatique, tel que cela est décrit dans la littérature. L'étude du m. semitendineux a montré de nouveaux aspects anatomiques dans sa vascularisation. Dans tous les cas ce muscle recevait sa vascularisation principale de l'artère circonflexe médiale près de la tubérosité ischiatique et de la deuxième a. perforante. Son innervation venait de deux branches motrices du nerf sciatique. Ces deux muscles répondaient aux critères nécessaires pour leur transposition comme néo sphincter. Cependant, compte-tenu de sa vascularisation et de son innervation, le m. semitendineux répond mieux aux impératifs anatomiques que le long chef du biceps et représente une alternative au muscle gracile pour la création d'un néo sphincter anal.

     

Identification of MEN1 gene mutations in sporadic carcinoid tumors of the lung

Lung carcinoids occur sporadically and rarely in association with multiple endocrine neoplasia type 1 (MEN1). There are no well defined genetic abnormalities known to occur in these tumors. We studied 11 sporadic lung carcinoids for loss of heterozygosity (LOH) at the locus of the MEN1 gene on chromosome 11q13, and for mutations of the MEN1 gene using dideoxy fingerprinting. Additionally, a lung carcinoid from a MEN1 patient was studied. In four of 11 (36%) sporadic tumors, both copies of the MEN1 gene were inactivated. All four tumors showed the presence of a MEN1 gene mutation and loss of the other allele. Observed mutations included a 1 bp insertion, a 1 bp deletion, a 13 bp deletion and a single nucleotide substitution affecting a donor splice site. Each mutation predicts truncation or potentially complete loss of menin. The remaining seven tumors showed neither the presence of a MEN1 gene mutation nor 11q13 LOH. The tumor from the MEN1 patient showed LOH at chromosome 11q13 and a complex germline MEN1 gene mutation. The data implicate the MEN1 gene in the pathogenesis of sporadic lung carcinoids, representing the first defined genetic alteration in these tumors.      

Parietal somatosensory association cortex mediates affective blindsight

To investigate the neural substrates underlying emotional feelings in the absence of a conscious stimulus percept, we presented a visual stimulus in the blind field of partially cortically blind patients and measured cortical activity (by functional magnetic resonance imaging, fMRI) before and after the stimulus had been paired with an aversive event. After pairing, self-reported negative emotional valence and blood oxygen level-dependent (BOLD) responses in somatosensory association areas were enhanced, whereby somatosensory activity predicted highly corresponding reported feelings and startle reflex amplitudes across subjects. Our data provide direct evidence that cortical activity representing physical emotional states governs emotional feelings.     

Head and neck paragangliomas: clinical and molecular genetic classification

Head and neck paragangliomas are tumors arising from specialized neural crest cells. Prominent locations are the carotid body along with the vagal, jugular, and tympanic glomus. Head and neck paragangliomas are slowly growing tumors, with some carotid body tumors being reported to exist for many years as a painless lateral mass on the neck. Symptoms depend on the specific locations. In contrast to paraganglial tumors of the adrenals, abdomen and thorax, head and neck paragangliomas seldom release catecholamines and are hence rarely vasoactive. Petrous bone, jugular, and tympanic head and neck paragangliomas may cause hearing loss. The internationally accepted clinical classifications for carotid body tumors are based on the Shamblin Class I-III stages, which correspond to postoperative permanent side effects. For petrous-bone paragangliomas in the head and neck, the Fisch classification is used. Regarding the molecular genetics, head and neck paragangliomas have been associated with nine susceptibility genes: NF1, RET, VHL, SDHA, SDHB, SDHC, SDHD, SDHAF2 (SDH5), and TMEM127. Hereditary HNPs are mostly caused by mutations of the SDHD gene, but SDHB and SDHC mutations are not uncommon in such patients. Head and neck paragangliomas are rarely associated with mutations of VHL, RET, or NF1. The research on SDHA, SDHAF2 and TMEM127 is ongoing. Multiple head and neck paragangliomas are common in patients with SDHD mutations, while malignant head and neck paraganglioma is mostly seen in patients with SDHB mutations. The treatment of choice is surgical resection. Good postoperative results can be expected in carotid body tumors of Shamblin Class I and II, whereas operations on other carotid body tumors and other head and neck paragangliomas frequently result in deficits of the cranial nerves adjacent to the tumors. Slow growth and the tendency of hereditary head and neck paragangliomas to be multifocal may justify less aggressive treatment strategies.