Linking cognitive integrity to working memory dynamics in the aging human brain

Aging is accompanied by a decline of working memory, an important cognitive capacity that involves stimulus-selective neural activity that persists after stimulus presentation. Here, we unraveled working memory dynamics in older human adults (male and female) including those diagnosed with mild cognitive impairment (MCI) using a combination of behavioral modeling, neuropsychological assessment, and magnetoencephalographic (MEG) recordings of brain activity. Younger adults (male and female) were studied with behavioral modeling only. Participants performed a visuo-spatial delayed match-to-sample task under systematic manipulation of the delay and distance between sample and test stimuli. Their behavior (match/non-match decisions) was fit with a computational model permitting the dissociation of noise in the internal operations underlying the working memory performance from a strategic decision threshold. Task accuracy decreased with delay duration and sample/test proximity. When sample/test distances were small, older adults committed more false alarms than younger adults. The computational model explained the participants' behavior well. The model parameters reflecting internal noise (not decision threshold) correlated with the precision of stimulus-selective cortical activity measured with MEG during the delay interval. The model uncovered an increase specifically in working memory noise in older compared to younger participants. Furthermore, in the MCI group, but not in the older healthy controls, internal noise correlated with the participants' clinically assessed cognitive integrity. Our results are consistent with the idea that the stability of working memory contents deteriorates in aging, in a manner that is specifically linked to the overall cognitive integrity of individuals diagnosed with MCI.Significance statement Several cognitive functions decline during aging, and this process is aggravated in MCI - a condition constituting a primary risk factor for developing dementia. One function susceptible to age-related cognitive decline is working memory: the ability to maintain information online for the flexible control of behavior, which entails persistent stimulus-selective neural activity in different regions of the cerebral cortex. We used computational modeling of behavioral and neural recordings to show that the stability of working memory contents is reduced in older human subjects and predicts overall cognitive decline in MCI patients. Our findings provide new mechanistic insight into cognitive aging and MCI and highlight working memory stability as an objective marker of the mechanisms underlying cognitive impairment.

The surgical anatomy of a (robot-assisted) minimally invasive transcervical esophagectomy

BACKGROUND

Transcervical esophagectomy allows for esophagectomy through transcervical access and bypasses the thoracic cavity, thereby eliminating single lung ventilation. A challenging surgical approach demands thorough understanding of the encountered anatomy. This study aims to provide a comprehensive overview of surgical anatomy encountered during the (robot-assisted) minimally invasive transcervical esophagectomy (RACE and MICE).

METHODS

To assess the surgical anatomy of the lower neck and mediastinum, MR images were made of a body donor after, which it was sliced at 24-μm intervals with a cryomacrotome. Images were made every 3 slices resulting in 3.200 images of which a digital 3D multiplanar reconstruction was made. For macroscopic verification, microscopic slices were made and stained every 5 mm (Mallory-Cason). Schematic drawings were made of the 3D reconstruction to demonstrate the course of essential anatomical structures in the operation field and identify anatomical landmarks.

RESULTS

Surgical anatomy 'boxes' of three levels (superior thoracic aperture, upper mediastinum, subcarinal) were created. Four landmarks were identified: (i) the course of the thoracic duct in the mediastinum; (ii) the course of the left recurrent laryngeal nerve; (iii) the crossing of the azygos vein right and dorsal of the esophagus; and (iv) the position of the aortic arch, the pulmonary arteries, and veins.

CONCLUSIONS

The presented 3D reconstruction of unmanipulated human anatomy and schematic 3D 'boxes' provide a comprehensive overview of the surgical anatomy during the RACE or MICE. Our findings provide a useful tool to aid surgeons in learning the complex anatomy of the mediastinum and the exploration of new surgical approaches such as the RACE or MICE.

[Revised version of the 4th edition of the WHO classification of malignant lymphomas : What is new?]

After 8 years, the WHO has now published the updated version of the 4th edition of the classification of hematopoietic and lymphoid tumors. This update provides a conceptual rewrite of existing entities as well as some new provisional entities and categories, particularly among the aggressive B‑cell lymphomas. Important new diagnostic categories include the high-grade B‑cell lymphomas, the large B‑cell lymphoma with IRF4 rearrangement, and the Burkitt-like lymphoma with 11q aberrations. Of particular importance, new concepts concerning the taxonomy and classification of early lymphoid lesions or precursor lesions are included, such as the in situ follicular neoplasia or the in situ mantle cell neoplasia. In addition, the concept of indolent lymphoproliferations, such as breast-implant-associated anaplastic large cell lymphoma and the indolent T‑cell lymphoproliferative disorder of the gastrointestinal tract, has been strengthened. Finally, diagnostic criteria for existing lymphoma entities have been refined.

[Minimally invasive robot-assisted gastric bypass after open Mason reduction gastroplasty]

BACKGROUND

The introduction of robot-assisted surgery in the treatment of morbidly obese patients has enlarged the armamentarium for surgeons involved in bariatric surgery. This article describes the experiences with a conversion surgery from a complicated open Mason gastroplasty to a Roux en Y gastric bypass using the da Vinci Xi robotic system.

CASE

A 29-year-old female patient underwent a Mason reduction gastroplasty by laparotomy in 1995 (body mass index BMI 53.2 kg/m²). The course was complicated with a revision due to abscess formation and subsequent secondary healing. In 1996 an open revision of the gastroplasty due to persisting gastroesophageal reflux disease and outlet stenosis with dilatation of the outlet and an open cholecystectomy for cholecystolithiasis were performed . Abdominoplasty was performed for skin flaps in 2001 after the patient had lost 68 kg in weight. The patient presented at our hospital because of insufficient weight reduction even with weight gain since 2001 and treatment-refractive gastroesophageal reflux with adhesion problems. Clinical examination revealed normal scar tissue formation with no indications for an incisional hernia. The BMI was 48.2 kg/m² with a body weight of 124 kg. The surgery was performed using a da Vinci Xi robotic system after access via a blunt dissection with the introduction of two trocars and adhesiolysis. The gastric pouch was created using Echelon 60 mm cartridges via an additional trocar. The gastroenterostomy was constructed with a 150 cm alimentary loop and a 60 cm biliodigestive loop resulting in a Roux en Y bypass. The operating time was 224 min.

RESULTS

The postoperative course was uneventful. Enteral nutrition was resumed on day 2 and the patient was discharged from the hospital 4 days postoperation.

CONCLUSION

This preliminary experience suggests that robotic revisional surgery can be performed safely even after complicated bariatric operations.

[Robotic pylorus-preserving pancreaticoduodenectomy : Video article]

Pylorus-preserving pancreaticoduodenectomy is one of the most complex procedures in general surgery. Laparoscopic pancreaticoduodenectomy was initially described in 1994; however, its worldwide distribution is so far limited to only a few specialist centers. Robotic surgery using the DaVinci® system can overcome many limitations of laparoscopic surgery. The system is a promising tool for a more widespread introduction of minimally invasive surgery for pancreatic diseases. Mortality rates of 0-5% and pancreatic fistula rates of 0-35% are described in the literature; therefore, thorough complication management is crucial in the postoperative course. The video presents a robotic pylorus-preserving pancreaticoduodenectomy for periampullary carcinoma in a female patient.

[Aggressive B‑cell lymphomas : Recommendations from the German Panel of Reference Pathologists in the Competence Network on Malignant Lymphomas on diagnostic procedures according to the current WHO classification, update 2017]

The update of the 4th edition of the WHO classification for hematopoietic neoplasms introduces changes in the field of mature aggressive B‑cell lymphomas that are relevant to diagnostic pathologists. In daily practice, the question arises of which analysis should be performed when diagnosing the most common lymphoma entity, diffuse large B‑cell lymphoma. We discuss the importance of the cell of origin, the analysis of MYC translocations, and the delineation of the new WHO entities of high-grade B‑cell lymphomas.

Discordant Results Obtained for Different Methods of HER-2/Neu Testing in Breast Cancer – A Question of Standardization, Automation and Timing

Background

HER-2/neu positivity is required for the selection of stage IV breast cancer patients for trastuzumab therapy. We compared the results of the recommended immunohistochemistry (IHC) evaluation with the automated ACIS™ IHC system and with fluorescence in situ hybridization (FISH). These HER-2/neu tissue results were correlated with the serum HER-2/neu (sHER-2/neu) levels at the time of metastatic spread.

Patients and Methods

A total of 61 IHC slides from 30 patients were stained using the HercepTest™. HER-2/neu gene amplification was determined using the Ventana™ FISH assay. sHER-2/neu levels were measured with the Oncogene Science” ELISA kit. The concordance of HER-2/neu results was determined using the concordance index Kappa (κ).

Results

The best concordance between any IHC and FISH was found for the automated ACIS system (88.5%, κ=0.68, category “good”). The comparison between the manual interpretations and the automated IHC was categorized as “very good” (95.1%, κ=0.85). The median sHER-2/neu level of FISH positive patients was significantly higher (67 ng/mL) than that of FISH negative patients (17 ng/mL, p=0.018). The increase in HER-2/neu positivity comparing tissue to stage IV serum was statistically significant (p=0.001).

Conclusions

The concordance between conventional IHC and computerized analysis was very good. The number of patients with stage IV breast cancer with an elevated sHER-2/neu level was much higher than HER-2/neu positivity in tissue. This discrepancy is only partially explained by the influence of tumor load. Patients with an elevated sHER-2/neu level and no tissue overexpression should be considered for retesting of tissue or a new biopsy.

Fully robotic da Vinci Ivor-Lewis esophagectomy in four-arm technique-problems and solutions

The aim of this technical note is a step-by-step description of a fully robotic abdominothoracic esophagectomy with an intrathoracic esophagogastrostomy. We report on our technique and short-term results of 75 patients undergoing an Ivor-Lewis esophagectomy using a fully robotic 4-arm approach in the abdominal and thoracic phase with a hand-sewn intrathoracic anastomosis. There are several important steps and differences to consider compared to the conventional minimal invasive approach (patient's positioning, anaesthesiological set up, port placement, gastric conduit pull up, technique of esophagostrostomy). Mean operative time was 392 minutes (240-610) with a 94% R0 resection status. Conversion to open procedure occurred in 2 (2.6%) in the abdominal, and 14 (18.2%) in the thoracic phase. Main reasons for conversion were problems during the lifting of the gastric conduit and difficulties in the construction of the esophagogastrostomy. The rate dropped during the last 20 patients (1/20 (10%). Our results suggest that the reported technique is safe and feasible. It satisfies the oncological principles and provides the advantages of robotic assisted minimal invasive surgery.

Similar clinical features in follicular lymphomas with and without breaks in the BCL2 locus

Approximately 15% of follicular lymphomas (FLs) lack breaks in the BCL2 locus. The aim of this study was to better define molecular and clinical features of BCL2-breakpoint/t(14;18)-negative FLs. We studied the presence of BCL2, BCL6 and MYC breaks by fluorescence in situ hybridization and the expression of BCL2, MUM1, CD10, P53 and Ki67 in large clinical trial cohorts of 540 advanced-stage FL cases and 116 early-stage disease FL patients treated with chemotherapy regimens and radiation, respectively. A total of 86% and 53% of advanced- and early-stage FLs were BCL2-breakpoint-positive, respectively. BCL2 was expressed in almost all FLs with BCL2 break and also in 86% and 69% of BCL2-breakpoint-negative advanced- and early-stage FLs, respectively. CD10 expression was significantly reduced in BCL2-breakpoint-negative FLs of all stages and MUM1 and Ki67 expression were significantly increased in BCL2-break-negative early-stage FLs. Patient characteristics did not differ between FLs with and without BCL2 breaks and neither did survival times in advanced-stage FLs. These results suggest that the molecular profile differs to some extent between FLs with and without BCL2 breaks and support the notion that FLs with and without BCL2 breaks belong to the same lymphoma entity.

A new monoclonal antibody (CAL2) detects CALRETICULIN mutations in formalin-fixed and paraffin-embedded bone marrow biopsies

Recent advances in the diagnostic of myeloproliferative neoplasms (MPNs) discovered CALRETICULIN (CALR) mutations as a major driver in these disorders. In contrast to JAK2 mutations being mainly associated with polycythaemia vera, CALR mutations are only associated with primary myelofibrosis (PMF) and essential thrombocythaemia (ET). CALR mutations are present in the majority of PMF and ET patients lacking JAK2 and MPL mutations. As these CALR mutations are absent from reactive bone marrow (BM) lesions their presence indicates ET or PMF. So far these mutations are detectable only by molecular assays. Their molecular detection is cumbersome because of the great CALR mutation heterogeneity. Therefore, the availability of a simple assay would be of great help. All CALR mutations reported lead to a frameshift generating a new 36 amino-acid C-terminus. We generated a monoclonal antibody (CAL2) to this C-neoterminus by immunizing mice with a representative peptide and compared its performance with Sanger sequencing data in 173 MPNs and other BM diseases. There was a 100% correlation between the molecular and the CAL2 immunohistochemical (IHC) assays. Thus, the detection of CALR mutations by the CAL2 IHC is a specific, sensitive, rapid, simple and low-cost method.

Electrical activity of the diaphragm (Edi) values and Edi catheter placement in non-ventilated preterm neonates

OBJECTIVE

The electrical activity of the diaphragm (Edi) reflects neural respiratory drive. Edi peak correlates with inspiratory drive and Edi minimum (Edi min) correlates with the tonic activity of the diaphragm. Edi data in non-ventilated preterm neonates have not been determined.The primary aim of this study was to determine Edi values in non-ventilated preterm neonates throughout postnatal maturation and with various types of noninvasive respiratory support. The secondary aim was to evaluate the success or complications of placement of the Edi catheter in premature neonates.

STUDY DESIGN

This was a prospective observational study of non-ventilated neonates <33 weeks gestation. Data were collected weekly using an Edi catheter placed in neonates on highflow nasal cannula (HFNC), nasal cannula (NC) or room air (RA). Clinical stability was determined by measuring heart rate (HR), respiratory rate (RR) and oxygen saturation (Sats). Success and adverse events of Edi catheter placement was monitored. Statistics were obtained by analysis of variance, P<0.05 was considered significant.

RESULT

Seventeen neonates were enrolled at 26 to 33 weeks postmenstrual age and studied from 1 to 10 weeks in duration. Overall Edi peak was 10.8±3.7 mcV (range 3.7 to 18.7) and Edi min was 2.8±1.1 mcV (range 0.8 to 7.6). There was no difference in Edi peak and min over postmenstrual ages within or between neonates, and no difference between those neonates on HFNC, NC or RA. HR, RR and Sats were not different over postmenstrual age or between any groups. The Edi catheter was placed successfully in 100% of these neonates. There were no adverse events noted.

CONCLUSION

In clinically stable neonates, the inspiratory drive (Edi peak) and tonic activity (Edi min) do not change with postnatal maturation or with the level of noninvasive respiratory support. The Edi catheter can be placed successfully in these premature neonates. These Edi data have the potential to guide ventilatory management of premature neonates.

Expression of the CD2AP adaptor molecule in normal, reactive and neoplastic human tissue

AIMS

To study the expression of CD2-associated protein (CD2AP), an adaptor protein involved in T-cell signalling and renal function, in normal, reactive and neoplastic human lymphoid tissues.

METHODS AND RESULTS

We used immunohistochemical techniques to evaluate monoclonal antibodies against CD2AP on over 400 formalin fixed paraffin embedded tissue blocks retrieved from the host institutions of three authors. The samples tested included normal, reactive and neoplastic lymphoid tissue. In lymphoid tissues, strong CD2AP staining was observed in plasmacytoid dendritic cells (pDCs), weak and variable in mantle zone B cells and moderate in rare germinal center cells. CD2AP labeled cortical and rare medullary thymocytes and isolated mononuclear cells in bone marrow trephines. Furthermore, epithelial and endothelial cells expressed CD2AP. Among neoplasms, the greatest number of CD2AP-positive cases were found in diffuse large B cell (21/94), NK T-cell lymphomas (7/67), "blastic plasmacytoid dendritic cell neoplasms" (9/10) and some types of solid tumor.

CONCLUSIONS

Our finding that mature peripheral T cells are CD2AP-negative but immature cortical thymocytes are positive may prove useful for diagnostic purposes. Moreover, our results demonstrate that CD2AP represents a useful marker of normal and neoplastic pDC and may be used in a diagnostic panel in reactive or neoplastic lymphoid proliferations.

The different epidemiologic subtypes of Burkitt lymphoma share a homogenous micro RNA profile distinct from diffuse large B-cell lymphoma

Sporadic Burkitt lymphoma (sBL) can be delineated from diffuse large B-cell lymphoma (DLBCL) by a very homogeneous mRNA expression signature. However, it remained unclear whether all three BL variants-sBL, endemic BL (eBL) and human immunodeficiency virus-associated BL (HIV-BL)-represent a uniform biological entity despite their differences in geographical occurrence, association with immunodeficiency and/or incidence of Epstein-Barr virus (EBV) infection. To address this issue, we generated micro RNA (miRNA) profiles from 18 eBL, 31 sBL and 15 HIV-BL cases. In addition, we analyzed the miRNA expression of 86 DLBCL to determine whether miRNA profiles recapitulate the molecular differences between BL and DLBCL evidenced by mRNA profiling. A signature of 38 miRNAs containing MYC regulated and nuclear factor-kB pathway-associated miRNAs was obtained that differentiated BL from DLBCL. The miRNA profiles of sBL and eBL displayed only six differentially expressed miRNAs, whereas HIV and EBV infection had no impact on the miRNA profile of BL. In conclusion, miRNA profiling confirms that BL and DLBCL represent distinct lymphoma categories and demonstrates that the three BL variants are representatives of the same biological entity with only marginal miRNA expression differences between eBL and sBL.

[Embolization of acute abdominal and thoracic hemorrhages with ethylene vinyl alcohol copolymer (Onyx): initial experiences with arteries of the body trunk]

During the last years most embolizations with the liquid agent Onyx have been performed in the field of neuroradiological interventions. There is minimal experience with arterial embolizations of the body trunk. 23 patients suffering from acute abdominal or thoracic bleeding underwent 28 embolizations with Onyx (17 male, 6 female, mean age 69 years). 27 interventions were technically and clinically successful. One patient with rebleeding from a jejunal artery aneurysm underwent surgery. Onyx embolizations were performed in renal, hepatic, iliac and bronchial arteries and esophageal varices. Compared with prior embolisation agents Onyx offers advantages due to good controllability. Fast arterial occlusion improves time management of patients. In comparison with prior techniques we observed a significant reduction of fluoroscopy time. Quantitative measurements demonstrated a significant higher embolisation agent contrast.

[Primary ductal adenocarcinoma near the orbit]

The case of a 59-year-old patient is described who presented with a left-sided pressure sensation in the left orbit and exophthalmus with a proud bulbus. The limited bulbus motility led to double vision. A preoperative MRI showed a space-occupying lesion in the left medial orbit. The morphological and immunohistochemical findings led to the diagnosis of a primary ductal carcinoma resembling salivary duct carcinoma (SDC). The tumor could be removed without compromising the eye. The patient suffers no side-effects or recurrences 12 months later.

Precursor T-lymphoblastic lymphoma within a recurrent pituitary adenoma

Only single examples of lymphoma associated with pituitary adenoma have been reported. In our patient, a precursor T-lymphoblastic lymphoma developed within a recurrent pituitary adenoma 17 years after the first resection. Histomorphologically, lymphoma and adenoma components were tightly admixed. The features harbour remarkable similarity to the previous report by Kuhn et al.. In both patients the lymphomas were composed of T-cells, there was no evidence of further sites involved, and both adenomas expressed follicle-stimulating hormone. The hormone may have posed a proliferative and transforming effect on lymphatic cells and could have played a crucial role in "lymphomagenesis" as an exceptional phenomenon.

The biological basis of the bone-muscle inter-relationship in the algorithm of fracture healing

The biological cascade of fracture healing is intimately linked to the muscle envelope. It further depends on the preservation of stable, perpetual axial micromovements. The current study was designed to demonstrate that high molecular weight bioactive substances diffuse from the muscle envelope to initiate osteoinductive activity at experimental fracture sites. Forty-eight rats underwent an experimental fracture of the left tibia and stabilization with an intramedullary 20-gauge needle. The animals were divided into 4 groups (A-D) of 12 rats each according to the post-fracture treatment. In group A (control) no additional treatment was applied following fracture and intramedullary fixation. In groups B, C, and D, a nitrocellulose membrane of various sizes was wrapped around the fracture, separating the periosteum from the muscle envelope. The groups differed by the membrane pore size, allowing passage of the following molecular sizes: 50 kilodaltons (kDa), 12 to 14 kDa, and 3.5 kDa in groups B, C, and D, respectively. Four animals in each group were sacrificed 2, 5, and 10 weeks after the procedure for radiographic and histological evaluation of fracture healing. Radiographic evaluation revealed a decreased rate of bone synthesis that correlated with the nitrocellulose pore size. Morphological and functional analysis of the bone explants indicated poorly healed fractures in groups B, C, and D. Direct contact between fractured bone and its muscle envelope is essential for the biological sequence of new bone formation. The extent of obstruction between the fracture and its muscle envelope correlates with the delay in fracture healing.

Pathway activation patterns in diffuse large B-cell lymphomas

Deregulation of cell signaling pathways controlling cell growth and cell survival is a common feature of all cancers. Although a core repertoire of oncogenic mechanisms is widely conserved between various malignancies, the constellation of pathway activities can vary even in patients with the same malignant disease. Modern molecularly targeted cancer drugs intervene in cell signaling compensating for pathway deregulation. Hence characterizing tumors with respect to pathway activation will become crucial for treatment decisions. Here we have used semi-supervised machine learning methodology to generate signatures of eight oncogene-inducible pathways, which are conserved across epithelial and lymphoid tissues. We combined them to patterns of pathway activity called PAPs for pathway activation patterns and searched for them in 220 morphologically, immunohistochemically and genetically well-characterized mature aggressive B-cell lymphomas including 134 cases with clinical data available. Besides Burkitt lymphoma, which was characterized by a unique pattern, the PAPs identified four distinct groups of mature aggressive B-cell lymphomas across independent gene expression studies with distinct biological characteristics, genetic aberrations and prognosis. We confirmed our findings through cross-platform analysis in an independent data set of 303 mature aggressive B-cell lymphomas.