In Vivo Whole-Nerve Electrophysiology Setup, Action Potential Recording, and Data Analyses in a Rodent Model.

In vivo rodent, whole peripheral nerve models are useful for studying the electrical conduction of sensory and motor fibers under normal physiological conditions as well as for assessing neurological outcomes after the application of physical alterations or pharmacological agents to the nervous system. Significant literature has focused on single-neuron and central nervous system electrophysiology protocol development. However, creation and development of in vivo whole-nerve electrophysiological recording protocols are sparse in the scientific literature. Here, detailed protocols for designing and building an in vivo whole-nerve electrophysiology system are described, including straightforward techniques to create working stimulation and recording electrodes that may be adapted to numerous study designs. Further, we include details for rodent anesthesia, surgical dissection (for the sciatic nerve), compound action potential signal optimization, data acquisition, data analyses, and troubleshooting tips. © 2021 Wiley Periodicals LLC. Basic Protocol 1: In vivo electrophysiology system wiring, hardware, and software setups Support Protocol 1: Design and 3D printing of electrophysiology base electrodes Support Protocol 2: Building needle electrodes Basic Protocol 2: Rodent anesthesia and surgery for nerve exposure Basic Protocol 3: Compound action potential recording and troubleshooting using WinWCP Basic Protocol 4: Compound action potential data analysis using WinWCP.

FLT3 Gene Involvement in B-cell Acute Lymphoblastic Leukemia (B-ALL).

OBJECTIVES: The FMS-like tyrosine kinase 3 gene (FLT3) is a receptor tyrosine kinase expressed in early hematopoietic progenitors that play an important role in hematopoietic development. The signaling pathways that are stimulated by the FLT3 protein manage several crucial cellular processes including division, growth, and survival of cells, specifically of hematopoietic progenitor cells. Activating mutations of this gene have been highly discussed in myeloid malignancies, including myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). However, FLT3 mutations are also observed in around 5% of acute lymphoblastic leukemia (ALL) patients. These mutations were usually found to be one of the four types: internal tandem duplications, tyrosine kinase domain mutations, juxtamembrane insertion and deletion, and juxtamembrane point mutation. The presence of FLT3 mutations in pediatric B-ALL patient populations tend to be associated with relapse and poor prognosis. These mutations are also correlated with poor prognosis in adult B-ALL patients. Due to the rarity of FLT3 mutations in B-ALL patients, there have been many challenges in attempts to understand their role in pathogenesis. In this review, we will discuss the most recent literature and trends associated with FLT3 mutations in B-ALL patients in order to elucidate their cytogenetic, molecular, and clinical implications.

Cytogenetic Findings in a Case of Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN).

OBJECTIVES: Blastic plasmacytoid dendritic cell neoplasm (BPDCN), previously known as natural killer (NK) cell leukemia/lymphoma, is categorized by the World Health Organization as a sole entity. Most often, BPDCN presents with features of both lymphoma and leukemia. The average age at diagnosis is 60 to 70 years and there are more men than women who are diagnosed with BPDCN. Herein we report a 67-year-old female with a recent peripheral blood morphology revealing a hematopoietic leukemia process. Flow cytometry revealed an atypical cell population without B-cell or T-cell lineage expression. It was positive for CD45 and CD123 and negative for CD34. The peripheral blood showed blastic plasmacytoid dendritic cell neoplasm, macrocytic anemia and moderate thrombocytopenia. Chromosome analysis showed an abnormal clone with i(7)(q10) and monosomies of chromosomes 13 and 15. She underwent a bone marrow biopsy. Bone marrow and peripheral blood showed a blastic plasmacytoid dendritic cell neoplasm (BPDCN), hypercellular marrow (estimated 95%) with 90.4% blasts (aspirate smear).

Transient Myeloproliferative Disorder: A Cytogenomic Update.

OBJECTIVES: Transient myeloproliferative disorder (TMD), now more commonly known as transient abnormal myelopoiesis (TAM), is a condition closely associated with Down syndrome. Ninety-five percent of Down syndrome cases occur as a result of chromosomal nondisjunction and are rarely due to mosaicism or translocation. TMD is found exclusively in neonates and is most commonly characterized by trisomy 21, somatic GATA1 mutation, and the increased presence of megakaryoblasts. TMD often does not manifest clinically, but patients may show hepatomegaly, splenomegaly and other symptoms. While TMD is almost always present with trisomy 21, there are not many other cytogenetic abnormalities associated with TMD, with a few rare cases such as monosomy 7 and trisomy 8. Recent studies have suggested liver hematopoietic progenitor cells as the candidate for TMD origin. Furthermore, GATA1 mutations associated with TMD are found to encode for a stop codon in the N-terminal activation region of gene sequences. It has been shown that those mutations can cause overproliferation of megakaryocytes, which can cooperate with Down syndrome cells, which have trisomy 21, in the progression of TMD into acute megakaryoblastic leukemia (AMKL). Since GATA1 mutations are present in all cases of myeloid leukemia of Down Syndrome, monitoring GATA1 in patients with trisomy 21 may assist with earlier diagnosis of TMD. Another likely cause of TMD is the amplification of the RUNX1 transcription factor gene located on chromosome 21. It has been shown that RUNX1 is associated with leukemias of myeloid lineage. While most cases of TMD will spontaneously resolve, some will evolve into acute myeloid leukemia (AML). In this review, we will discuss the cytogenetic, molecular genetics and clinical aspects of TMD.

A t(8;14)(q24.1;q32) in Plasma Cell Myeloma: A Case Report and Literature Review.

OBJECTIVES: We report a 74-year-old male whose bone marrow morphology, flow cytometry, MRI and serum electrophoresis showed evidence of plasma cell myeloma. Chromosome analysis of the bone marrow showed an abnormal karyotype, described as 51~53,XY,+3,+5,t(8;14)(q24 .1;q32),+9,+11,+15,+19,+21[cp6]/46,XY[14]. The t(8;14)(q24.1;q32) is mainly seen in Burkitt lymphoma but it can also be seen in plasma cell myeloma usually with the context of a complex karyotype. Based on the Mitelman database the involvement of C-MYC is usually seen in late tumor progression in plasma cell myeloma as a secondary rearrangement, usually during clonal evolution and divergence and is associated with a significantly decreased survival. Our case pinpoints the involvement of MYC abnormalities in plasma cell myeloma as well as the importance of cytogenetics as a tool to manage and monitor plasma cell myeloma cases.

Duplication of the Band q21q27 on the Long Arm of Chromosome 3: A Rare Cytogenetic Event in B-Chronic Lymphocytic Leukemia (B-CLL).

OBJECTIVES: We present the case of an 83-year-old female with a long history of B-CLL followed by observation only. Twelve years after her diagnosis of CLL, routine follow-up chromosome analysis of peripheral blood revealed an abnormal metaphase with a dup(3)(q21q27) in 18 of 20 metaphase cells. To further characterize the abnormal chromosome 3, fluorescence in situ hybridization (FISH) was performed using the Abbott BCL6 probe for 3q27. An additional BCL6 signal was observed in 303 of the 500 interphase nuclei examined. The ISCN was reported as 46,XX,dup(3)(q21q27)[1]/46,XX[2]. nuc ish(5'BCL6, 3'BCL6)x3(5'BCL6 with 3'BCL6x3)[303/500]. This abnormality was seen again in one of three available metaphases in a follow-up peripheral blood study five years later, consistent with persistent disease. Molecular genetic analysis identified the presence of somatic hypermutation of the immunoglobulin heavy chain gene variable region (IGH-V), which is recognized as an independent favorable prognostic marker in CLL. FISH analysis was negative for loss of SEC63 (6q21), amplification of MYC (8q24), loss of ATM (11q22.3), trisomy 12, loss of D13S319 (13q14.3), loss of TP53 (17p13.1) and CCND1/MYEOV IGH rearrangement [t(11;14)(q13;q32.30)]. Partial trisomy 3 is a relatively rare event seen in B-CLL, with commonly overrepresented segments including the q21-23 region and the q25-29 region of the long arm of chromosome 3, as well as changes leading to gains of 3q26- q27. The clinical significance of this finding in B-CLL is uncertain; however, our patient remains well and has not required therapy 17 years after her initial diagnosis.