Neuroimaging Findings in Moebius Sequence.

BACKGROUND AND PURPOSE: Moebius sequence comprises a spectrum of brain congenital malformations predominantly affecting the function of multiple cranial nerves. Reported neuroimaging findings are heterogeneous and based on case reports or small case series. Our goal was to describe the neuroimaging findings of Moebius sequence in a large population of patients scanned with MR imaging. MATERIALS AND METHODS: An observational cross-sectional study was performed to assess brain MR imaging findings in 38 patients with Moebius syndrome studied between 2013 and 2016. RESULTS: Retrospective analysis of MR imaging studies showed flattening of the floor of the fourth ventricle floor secondary to a bilateral absent facial colliculus in 38 patients (100%) and unilateral absence in 1. A hypoplastic pons was found in 23 patients (60.5%). Mesencephalic malformations consisted of tectal beaking in 15 patients (39.5%) and increased anteroposterior midbrain diameter with a shallow interpeduncular cistern in 12 (31.6%). Infratentorial arachnoid cysts were found in 5 patients (13.2%), and cerebellar vermis hypoplasia, in 2 (5.3%). Supratentorial findings included the following: thalamic fusion (26.3%), periventricular nodular heterotopias (26.3%), ventriculomegaly (26.3%), callosal abnormalities (23.7%), and hippocampal malrotations (23.7%). CONCLUSIONS: Findings seen in this large patient cohort agreed with previously published reports. Flattening of the fourth ventricle floor secondary to a bilaterally absent facial colliculus was the most frequent MR imaging finding. The presence of other brain stem and cerebellar malformations as well as supratentorial abnormalities may help explain clinical symptoms and achieve a correct diagnosis.

Endovascular treatment of traumatic injuries of the vertebral artery.

BACKGROUND AND PURPOSE: There are a few reports regarding the treatment of traumatic vertebral arteriovenous fistulas and pseudoaneurysms. Our aim was to describe the clinical and angiographic results of endovascular therapy for traumatic injuries of the vertebral artery. MATERIALS AND METHODS: The clinical and angiographic features of 18 traumatic injuries of the vertebral artery during an 8-year period were reviewed. There were 14 male (78%) and 4 female patients (22%). The average age was 28 years (range, 11-49 years). Of the 18 lesions of the vertebral artery, 17 (95%) were the result of penetrating trauma (gunshot or stab wound injury) and 1 (5%) was iatrogenic (jugular vein catheter). In 16 (89%) instances, the injury resulted in an arteriovenous fistula, and in the other 2 (11%), in a pseudoaneurysm. All patients were treated with an endovascular approach by using different techniques (balloon occlusion, coil embolization, and/or stent deployment). RESULTS: Endovascular therapy resulted in immediate lesion total occlusion in 16 (89%) patients. Delayed total occlusion was demonstrated angiographically during follow-up in the 2 remaining patients. Clinical improvement was documented in all patients, and there were no clinically symptomatic complications. CONCLUSION: In this small series, endovascular techniques were a safe and effective method of treatment and were not associated with significant morbidity or mortality.

MR imaging of intramedullary and intradural-extramedullary spinal cysticercosis.

OBJECTIVE: The purpose of our study was to retrospectively review the MR imaging findings in a group of patients with clinically proven cysticercosis involving the spinal cord, the spinal subarachnoid space, or both. MATERIALS AND METHODS: We retrospectively reviewed images of 16 patients with clinically diagnosed spinal cysticercosis to summarize the imaging characteristics. All patients underwent T1- and T2-weighted sagittal, axial, or both sagittal and axial MR imaging before i.v. administration of paramagnetic contrast media. Thirteen patients also underwent sagittal, axial, or both sagittal and axial T1-weighted MR imaging after i.v. gadolinium administration. In addition, all patients underwent cranial CT, MR imaging, or both to reveal possible evidence of cranial cysticercosis. RESULTS: MR imaging revealed isolated intradural-extramedullary involvement (n = 9), isolated intramedullary involvement (n = 3), combined intradural-extramedullary and intramedullary involvement (n = 3), and/or syringomyelia caused by infection and associated with chronic spinal arachnoiditis (n = 2). Evidence of intradural-extramedullary disease included cystic structures within the subarachnoid space or homogeneous sheetlike enhancement within the subarachnoid space over the surface of the spinal cord. Evidence of intramedullary disease included focal cystic lesions or syringomyelic cavitation of the spinal cord. All patients had evidence of simultaneous intracranial cysticercosis as shown on cranial CT, MR imaging, or both. CONCLUSION: In the absence of scolex visualization, cysticercotic involvement of the spinal cord or spinal subarachnoid space has a nonspecific appearance on MR imaging. On the basis of the findings in this group of patients, we believe that spinal cysticercosis is most often accompanied by intracranial disease.

Perturbation of B cell genesis in the bone marrow of pristane-treated mice. Implications for plasmacytoma induction.

A single injection of pristane was given i.p. to plasmacytoma-susceptible BALB/cAn mice. At intervals up to 6 mo thereafter, immunofluorescence labeling of intranuclear terminal deoxynucleotidyl transferase (TdT), cell surface B220 glycoprotein, cytoplasmic mu-chains of IgM (c mu), and surface mu-chains (s mu), together with mitotic arrest techniques, were used to quantitate the in vivo population dynamics of precursor B cells in the bone marrow. TdT-expressing pro-B cells (TdT+B220-, TdT+B220+), before the expression of mu-chains, showed sustained increases in both population size and the number of cells flowing through mitosis per unit time. In contrast, populations of pre-B cells (c mu + s mu -) and B cells (s mu +) were consistently depressed for long periods of time, including the phase of plasmacytoma formation. Precursor B cells in DBA/2 mice, a plasmacytoma-resistant strain, showed similar responses to pristane treatment. The results demonstrate that a single injection of pristane, which greatly increases the demand for macrophage activity in the peritoneal space, causes sustained distant alterations in B cell lymphopoiesis in the bone marrow; specifically, a prolonged increased proliferation of pro-B cells coupled with a depression and a exaggerated loss of pre-B cells and B cells. The protracted stress on B cell lymphopoiesis may be a predisposing factor in the subsequent development of c-myc-activating chromosomal rearrangements that play a critical role in plasmacytomagenesis.

c-kit expression by B cell precursors in mouse bone marrow. Stimulation of B cell genesis by in vivo treatment with anti-c-kit antibody.

To examine the in vivo role of c-kit receptor in B lymphopoiesis we have evaluated precursor B cell populations expressing c-kit in mouse bone marrow and the effects on B cell genesis of administering a neutralizing anti-c-kit mAb, ACK2. Double immunofluorescence labeling and mitotic arrest were used to examine bone marrow cells from BALB/c mice. Almost one-half of TdT+ cells and one-quarter of B220+ cells coexpressed c-kit, mainly at low intensities, and were actively proliferating in vivo. c-kit+ cells that lacked B lineage markers expressed c-kit in high intensities and entered mitosis at an exceptionally rapid rate. In ACK2-treated mice, erythroid and granulocytic cells were almost completely absent from the bone marrow, whereas, in contrast, B lymphopoiesis was stimulated. Pre-B cells expressing cytoplasmic mu-chains; as well as TdT+B220+ cells before mu expression, were increased two- to fourfold in number and production rate. IgM-bearing B lymphocytes were increased in bone marrow and spleen. The results demonstrate that many early precursor B cells in mouse bone marrow constitutively express c-kit receptor. The failure of ACK2 treatment to block B lymphopoiesis, however, suggests that c-kit receptor function is not essential for precursor B cell development in vivo, but can be replaced by alternative signaling systems. The stimulation of B cell genesis by ACK2 treatment may reflect a conferred advantage in the competition for microenvironmental factors which underlies the balance between B lymphopoiesis and other hemopoietic lineages in vivo.

Dynamics and localization of early B-lymphocyte precursor cells (pro-B cells) in the bone marrow of scid mice.

Mice homozygous for the scid (severe combined immunodeficiency) mutation are generally unable to produce B lymphocytes, a condition attributed to defective rearrangement of immunoglobulin genes in precursor B cells. Some early B-lineage cells are present in the bone marrow (BM), however. In scid mice, we defined three subsets of early progenitor B cells lacking mu heavy chains (pro-B cells) based on the expression of terminal deoxynucleotidyl transferase (TdT) and B220 glycoprotein: (a) early pro-B cells (TdT+B220-), (b) intermediate pro-B cells (TdT+B220+), and (c) late pro-B cells (TdT-B220+). Double immunofluorescence labeling of BM cell suspensions has shown normal numbers of early and intermediate pro-B cells, substantially reduced numbers of late pro-B cells, and an absence of pre-B cells and B cells. Early and intermediate pro-B cells accumulated in metaphase in near-normal numbers after intraperitoneal (IP) vincristine administration. B220+ pro-B cells have been localized in BM sections by the binding of intravenously (IV) administered 125I monoclonal antibody (MoAb) 14.8, detected by light and electron microscope radioautography. Many B220+ cells were located peripherally in the bone-lining cell layers associated with stromal reticular cells. More centrally located B220+ cells were frequently associated with macrophages containing prominent cytoplasmic inclusions. Occasional B220+ cells were present in venous sinusoids. These results demonstrate that many pro-B cells in scid mice occupy microenvironments in the BM near the surrounding bone. The pro-B cells maintain normal rates of production during stages of presumptive mu heavy-chain gene rearrangement, apparently unaffected by the absence of a mature B cell pool. Nearly all defective cells then abort at the late pro-B cell stage and are deleted, apparently by macrophages. The findings contribute to models of in vivo differentiation, regulation, localization, and selection of early B-lineage cells in the BM.