CXCL12-stimulated lymphocytes produce secondary stimulants that affect the surrounding cell chemotaxis.

Chemotactic factors locally secreted from tissues regulate leukocyte migration via cell membrane receptors that induce intracellular signals. It has been suggested that neutrophils stimulated by bacterial peptides secrete a secondary stimulant that enhances the chemotactic cell migration of the surrounding cells. This paracrine mechanism contributes to chemokine-dependent neutrophil migration, however, it has not yet been extensively studied in lymphocytes. In this study, we provide evidence that lymphocytes stimulated by the chemokine, CXCL12, affect the CXCR4-independent chemotactic response of the surrounding cells. We found that CXCR4-expressing lymphocytes or the conditioned medium from CXCL12-stimulated cells promoted CXCR4-deficient cell chemotaxis. In contrast, the conditioned medium from CXCL12-stimulated cells suppressed CCR7 ligand-dependent directionality and the cell migration speed of CXCR4-deficient cells. These results suggest that paracrine factors from CXCL12-stimulated cells navigate surrounding cells to CXCL12 by controlling the responsiveness to CCR7 ligand chemokines and CXCL12.

Regulation of CCR7-dependent cell migration through CCR7 homodimer formation.

The chemokine receptor CCR7 contributes to various physiological and pathological processes including T cell maturation, T cell migration from the blood into secondary lymphoid tissues, and tumor cell metastasis to lymph nodes. Although a previous study suggested that the efficacy of CCR7 ligand-dependent T cell migration correlates with CCR7 homo- and heterodimer formation, the exact extent of contribution of the CCR7 dimerization remains unclear. Here, by inducing or disrupting CCR7 dimers, we demonstrated a direct contribution of CCR7 homodimerization to CCR7-dependent cell migration and signaling. Induction of stable CCR7 homodimerization resulted in enhanced CCR7-dependent cell migration and CCL19 binding, whereas induction of CXCR4/CCR7 heterodimerization did not. In contrast, dissociation of CCR7 homodimerization by a novel CCR7-derived synthetic peptide attenuated CCR7-dependent cell migration, ligand-dependent CCR7 internalization, ligand-induced actin rearrangement, and Akt and Erk signaling in CCR7-expressing cells. Our study indicates that CCR7 homodimerization critically regulates CCR7 ligand-dependent cell migration and intracellular signaling in multiple cell types.

Subarachnoid haemorrhage due to a lateral spinal artery aneurysm misdiagnosed as a posterior inferior cerebellar artery aneurysm: case report and literature review.

CLINICAL DESCRIPTION: A 61 year old man presenting with subarachnoid haemorrhage had a distal posterior inferior cerebellar artery (PICA) aneurysm diagnosed on the initial cerebral angiogram. However, a PICA aneurysm was not found during surgery. A follow-up, super-selective vertebral artery (VA) performed demonstrated a saccular aneurysm located on the lateral spinal artery (LSA). A right sub-occipital craniotomy was performed and the aneurysm arising was identified and obliterated with a small titanium clip. CONCLUSION: We describe the first example of an LSA aneurysm without occlusion or severe stenosis of the VA and PICA. This extremely rare lesion illustrates how knowledge of the angiographic features and super-selective cerebral angiography aids the precise diagnosis and the prevention of surgical complications.

Unusual location of anterior communicating artery aneurysm located on the planum sphenoidale due to long A1 segments.

A 51-year-old woman presented with a rare variation in the location of the anterior communicating artery (AComA) complex associated with aneurysm manifesting as sudden onset of headache. Computed tomography (CT) revealed widespread subarachnoid hemorrhage with intracerebral hematoma and intraventricular hemorrhage. Three-dimensional (3D)-CT angiography revealed an aneurysm located at the AComA complex on the planum sphenoidale. Surgical clipping of the aneurysm through the right pterional approach was performed without complication. AComA aneurysm located on the planum sphenoidale is extremely rare, but should be recognized in the planning of surgery in the AComA region. 3D-CT angiography is very useful for understanding the relationships between aneurysms and the surrounding structures.

Efficacy of endovascular surgery for the treatment of acute epidural hematomas.

BACKGROUND AND PURPOSE: Recent advances in the equipment and technology for endovascular surgery have led to an increasing number of patients undergoing this procedure to treat various lesions. The purpose of this study was to investigate the efficacy of early-stage endovascular surgery to treat growing acute epidural hematomas (AEDHs). METHODS: Over a period of 2.5 years, endovascular intervention was performed in nine patients with AEDHs, as shown by the extravasation of contrast medium and the recognition of growing hematomas on CT scans. Embolization was performed by using catheters superselectively advanced with a microguidewire until it reached the area just before the bleeding point. RESULTS: In all nine cases, bleeding from the middle meningeal artery ceased immediately after treatment, and further surgical intervention was avoided. In three of five patients with additional lesions, surgical intervention was also conducted to treat an acute subdural hematoma (two patients) or a contusion hematoma (one patient); in two cases, these lesions were located on the contralateral side. CONCLUSION: In patients with thin AEDHs in the early stage, angiography followed by endovascular intervention allows for conservative treatment. Notable clinical benefits can be achieved in patients with complicated, multiple lesions.

Diffusion-weighted MRI of the cervical cord in acute spinal cord injury with type II odontoid fracture.

The authors present a case of acute spinal cord injury demonstrated by diffusion-weighted MRI (DWI) of the cervical cord. DWI taken 2 hours after injury showed intramedullary hyperintensity with a decrease of the apparent diffusion coefficient (ADC) value at C1-C2 vertebral levels. On T -weighted images obtained 1 month after injury, the lesion was hyperintense, indicating the existence of myelomalacia. DWI of the cervical cord provided satisfactory images and was a useful method for detecting and visualizing of the affected cord in the super-early stage.(2)