Spatial Characteristics of Colonic Mucosa-Associated Gut Microbiota in Humans

Limited data exist on the spatial distribution of the colonic bacteria in humans. We collected the colonic biopsies from five segments of 27 polyp-free adults and collected feces from 13 of them. We sequenced the V4 region of the bacterial 16S rRNA gene using the MiSeq platform. The sequencing data were assigned to the amplicon sequence variant (ASV) using SILVA. Biodiversity and the relative abundance of the ASV were compared across the colonic segments and between the rectal and fecal samples. Bacterial functional capacity was assessed using Tax4fun. Each individual had a unique bacterial community composition (Weighted Bray-Curtis P value = 0.001). There were no significant differences in richness, evenness, community composition, and the taxonomic structure across the colon segments in all the samples. Firmicutes (47%), Bacteroidetes (39%), and Proteobacteria (6%) were the major phyla in all segments, followed by Verrucomicrobia, Fusobacteria, Desulfobacterota, and Actinobacteria. There were 15 genera with relative abundance > 1%, including Bacteroides, Faecalibacterium, Escherichia/Shigella, Sutterella, Akkermansia, Parabacteroides, Prevotella, Lachnoclostridium, Alistipes, Fusobacterium, Erysipelatoclostridium, and four Lachnospiraceae family members. Intra-individually, the community compositional dissimilarity was the greatest between the cecum and the rectum. There were significant differences in biodiversity and the taxonomic structure between the rectal and fecal bacteria. The bacterial community composition and structure were homogeneous across the large intestine in adults. The inter-individual variability of the bacteria was greater than inter-segment variability. The rectal and fecal bacteria differed in the community composition and structure.

PlateFlo - A software-controllable plate-scale perfusion system for culture of adherent cells

Here we present a versatile system for milliliter-scale perfusion culture of adherent cells that can be built using basic tools, based on a readily available one-well culture plate (84 cm² culture area). Media composition and flow paths can be programmatically controlled via USB serial interface using the FETbox hardware controller and associated PlateFlo Python package. The FETbox can control up to five high current 12 V devices such as common pinch valves, solenoids, and DC motor peristaltic pumps. It was designed to be easily customized with built-in accommodation for additional electronic components (e.g. analog sensors and input), use of the ubiquitous Arduino Nano platform, and easily expanded serial communication protocol. Multiple FETboxes can be used in parallel for additional devices. Applications of the PlateFlo system include perfusion culture of laboratory experiments requiring large cell numbers including genome-scale genetic screens and proteomics, as well as novel perfusion schemes including dynamic media conditions and sequential cell culture.

Establishment and Culture of Patient-Derived Primary Medulloblastoma Cell Lines

Established cell lines have been extensively used in cancer research. They are easy to obtain and expand and are composed of a relatively uniform population of cells. When experimental conditions are kept standard, these cells allow a high reproducibility of experimental findings from independent research groups. However, because these cell lines have been propagated in culture for decades, additional genetic lesions may be acquired leading to modification of their characteristics as compared to the original tumor. Primary cultures represent a valid alternative. Here, we describe standardized protocols to establish medulloblastoma (MB) patient-derived primary cultures from fresh tumor samples. MB primary cells grow as an adherent culture on a laminin coating and can be propagated in vitro for a limited number of passages, therefore reducing the chances to accumulate molecular alterations compared to long-term cultures. Consequently, they better resemble the original tumor both in terms of biological behavior and molecular characteristics. Low-passage MB primary cells can be used as an in vitro model for biochemical studies and functional assays, representing a useful tool to dissect the contribution of molecular pathways to MB pathogenesis. They can also represent a useful screening tool for potential therapeutic agents in preclinical studies.

Nerve-Adherent Giant Cell Tumors of Tendon Sheath: A New Presentation

BACKGROUND

Tenosynovial giant cell tumors are a group of slowly growing benign neoplasms of synovial membrane of joints, tendons, and bursae. The localized type or giant cell tumor of tendon sheath (GCTTS) is the extra-articular form of tenosynovial giant cell tumors. We describe two patients with a GCTTS, confirmed histologically at the time of surgical resection, that was adherent to peripheral nerves. Rare GCTTS can cause extrinsic compression of major nerves.

CASE DESCRIPTIONS

The first patient was a 36-year-old man with a left wrist mass associated with pain and paresthesia in the radial three digits. On ultrasound and magnetic resonance imaging (MRI), the mass appeared arising from the left median nerve with a picture suggestive of an atypical neurogenic tumor; however, the possibility of GCTTS could not be excluded. Intraoperatively, the tumor was adherent to the median nerve without a connection to nearby intercarpal joints. The second patient was a 25-year-old woman with a history of malignant melanoma and an incidentally discovered mass on routine follow-up. MRI of the pelvis showed an ovoid mass related to the right sciatic nerve. The MRI picture was suggestive of a GCTTS, although a benign neurogenic tumor was favored given the anatomic relation to the sciatic nerve. Intraoperatively, the tumor appeared as a nodule implanted on the nerve, and it was easily peeled off.

CONCLUSION

We present a new, rare presentation of GCTTS adherent to peripheral nerves with extrinsic compression. We suggest either an implantation mechanism or an unrecognized extrasynovial origin for such tumors.

Analysis of the impact of adherent perirenal fat on peri-operative outcomes of robotic partial nephrectomy

INTRODUCTION

Adherent perirenal fat (APF) can be defined as inflammatory fat sticking to renal parenchyma, whose dissection is difficult and makes it troublesome to expose the tumour. Our objective was to evaluate the impact of APF on the technical difficulty of robot-assisted partial nephrectomy (RPN).

PATIENTS AND METHODS

We analysed data of 202 patients who underwent RPN for a small renal tumour. Patients were divided into two groups according to the presence of APF. Peri-operative data were compared between the two groups. Predictors of APF were evaluated by univariate and multivariate analysis. The validity of the MAP score (radiological scoring system) was also assessed.

RESULTS

APF was observed in 80 patients (39.6 %). Tumour complexity and surgeon's experience were similar between both groups. Operative time was 40 min longer in the APF group (188.5 vs. 147.9 min, p < 0.0001). Blood loss was twice higher, and transfusions were more common in the APF group (694 vs. 330 ml, p < 0.0001 and 19 vs. 5.8 %, p = 0.003, respectively). APF was associated with an increased risk of conversion to open surgery (11.2 vs. 0 %, p = 0.0002) or radical nephrectomy (6.2 vs. 0.8 %, p = 0.03). In multivariate analysis, male gender (OR 13.2, p < 0.0001), obesity (OR 1.2, p = 0.007), hypertension (OR 3.7, p = 0.02), and MAP score (OR 3.3; p < 0.0001) were significant predictors of APF.

CONCLUSION

During RPN, APF is associated with increased bleeding and a higher risk of conversion to open surgery and to radical nephrectomy. Male gender, hypertension, obesity, and MAP score are predictors of APF.

Improved poliovirus D-antigen yields by application of different Vero cell cultivation methods

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Vero cells were grown in batch, semi-batch, perfusion and recirculation strategies.

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At high cell densities (to 5 × 10⁶ cells mL⁻¹) cells were infected with poliovirus.

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Increased cell densities allowed 3 fold increase in d-antigen yield.

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Cell specific d-antigen yields were lower at higher cell densities.

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The semi-batch cultivation strategy is most promising for optimization.

Vero cells were grown adherent to microcarriers (Cytodex 1; 3 g L⁻¹) using animal component free media in stirred-tank type bioreactors. Different strategies for media refreshment, daily media replacement (semi-batch), continuous media replacement (perfusion) and recirculation of media, were compared with batch cultivation. Cell densities increased using a feed strategy from 1 × 10⁶ cells mL⁻¹ during batch cultivation to 1.8, 2.7 and 5.0 × 10⁶ cells mL⁻¹ during semi-batch, perfusion and recirculation, respectively.

The effects of these different cell culture strategies on subsequent poliovirus production were investigated. Increased cell densities allowed up to 3 times higher d-antigen levels when compared with that obtained from batch-wise Vero cell culture. However, the cell specific d-antigen production was lower when cells were infected at higher cell densities. This cell density effect is in good agreement with observations for different cell lines and virus types. From the evaluated alternative culture methods, application of a semi-batch mode of operations allowed the highest cell specific d-antigen production.

The increased product yields that can easily be reached using these higher cell density cultivation methods, showed the possibility for better use of bioreactor capacity for the manufacturing of polio vaccines to ultimately reduce vaccine cost per dose. Further, the use of animal-component-free cell- and virus culture media shows opportunities for modernization of human viral vaccine manufacturing.