Cranioplastic Surgery and Acclimation Training for Awake Mouse fMRI

MRI is a promising tool for translational research to link brain function and structure in animal models of disease to patients with neuropsychiatric disorders. However, given that mouse functional MRI (fMRI) typically relies on anesthetics to suppress head motion and physiological noise, it has been difficult to directly compare brain fMRI in anesthetized mice with that in conscious patients. Here, we developed a new system to acquire fMRI in awake mice, which includes a head positioner and dedicated radio frequency coil. The system was used to investigate functional brain networks in conscious mice, with the goal of enabling future studies to bridge fMRI of disease model animals with human fMRI. Cranioplastic surgery was performed to affix the head mount and the cupped-hand handling method was performed to minimize stress during MRI scanning. Here we describe the new mouse fMRI system, cranioplastic surgery and acclimation protocol. Graphic abstract: Awake fMRI system to investigate the neuronal activity in awaked mice.

Differential effects of aquaporin-4 channel inhibition on BOLD fMRI and diffusion fMRI responses in mouse visual cortex

The contribution of astrocytes to the BOLD fMRI and DfMRI responses in visual cortex of mice following visual stimulation was investigated using TGN-020, an aquaporin 4 (AQP4) channel blocker, acting as an astrocyte function perturbator. Under TGN-020 injection the amplitude of the BOLD fMRI response became significantly higher. In contrast no significant changes in the DfMRI responses and the electrophysiological responses were observed. Those results further confirm the implications of astrocytes in the neurovascular coupling mechanism underlying BOLD fMRI, but not in the DfMRI responses which remained unsensitive to astrocyte function perturbation.

Awake functional MRI detects neural circuit dysfunction in a mouse model of autism

MRI has potential as a translational approach from rodents to humans. However, given that mouse functional MRI (fMRI) uses anesthetics for suppression of motion, it has been difficult to directly compare the result of fMRI in "unconsciousness" disease model mice with that in "consciousness" patients. We develop awake fMRI to investigate brain function in 15q dup mice, a copy number variation model of autism. Compared to wild-type mice, we find that 15q dup is associated with whole-brain functional hypoconnectivity and diminished fMRI responses to odors of stranger mice. Ex vivo diffusion MRI reveals widespread anomalies in white matter ultrastructure in 15q dup mice, suggesting a putative anatomical substrate for these functional hypoconnectivity. We show that d-cycloserine (DCS) treatment partially normalizes these anormalies in the frontal cortex of 15q dup mice and rescues some social behaviors. Our results demonstrate the utility of awake rodent fMRI and provide a rationale for further investigation of DCS therapy.

Expression and lysosomal targeting of CLN7, a major facilitator superfamily transporter associated with variant late-infantile neuronal ceroid lipofuscinosis

Neuronal ceroid lipofuscinoses (NCLs) constitute a group of progressive neurodegenerative disorders resulting from mutations in at least eight different genes. Mutations in the most recently identified NCL gene, MFSD8/CLN7, underlie a variant of late-infantile NCL (vLINCL). The MFSD8/CLN7 gene encodes a polytopic protein with unknown function, which shares homology with ion-coupled membrane transporters. In this study, we confirmed the lysosomal localization of the native CLN7 protein. This localization of CLN7 is not impaired by the presence of pathogenic missense mutations or after genetic ablation of the N-glycans. Expression of chimeric and full-length constructs showed that lysosomal targeting of CLN7 is mainly determined by an N-terminal dileucine motif, which specifically binds to the heterotetrameric adaptor AP-1 in vitro. We also show that CLN7 mRNA is more abundant in neurons than astrocytes and microglia, and that it is expressed throughout rat brain, with increased levels in the granular layer of cerebellum and hippocampal pyramidal cells. Interestingly, this cellular and regional distribution is in good agreement with the autofluorescent lysosomal storage and cell loss patterns found in brains from CLN7-defective patients. Overall, these data highlight lysosomes as the primary site of action for CLN7, and suggest that the pathophysiology underpinning CLN7-associated vLINCL is a cell-autonomous process.

Bovine pericardium as a wrapping for orbital implants

PURPOSE

We report the use of bovine pericardium as an alternative wrapping for porous orbital implants after enucleation.

METHODS

We retrospectively reviewed the records of all patients who received a bovine pericardium-wrapped orbital implant after enucleation by the authors between August 1, 1996, and December 1, 1999.

RESULTS

Eighty patients underwent placement of bovine pericardium-wrapped orbital implants. The average age at the time of implantation was 49.3 years (range, 5 years to 83 years). The mean follow-up interval was 11.8 months (range, 2 to 41 months). There were no intraoperative complications. No patient had secondary systemic infection or showed evidence of rejection. There was no clinical evidence to suggest that vascularization of the porous implant was unusually delayed, and there were no complications after secondary drilling and placement of a coupling post. Four (5%) of 80 patients had complications requiring removal of the spherical implant. All 4 patients had hydroxyapatite implants. Two patients had significant exposure requiring removal of the implant at 2 months after surgery; 1 patient had a chronic fistulous tract with secondary infection 3 years after surgery: and 1 patient had chronic orbital pain requiring removal of the implant at 1 year after surgery.

CONCLUSIONS

The incidence of implant exposure was less than 4%. This compares favorably to the incidence of exposure of 9% to 21% reported in recent literature. Other complications were few and of minimal clinical significance. The authors conclude that bovine pericardium is a viable option to sclera as a wrapping for porous orbital implants.

Blepharoptosis-induced superior keratoconus

PURPOSE

This clinical case report demonstrates blepharoptosis-induced corneal steepening and its subsequent resolution after blepharoptosis surgery.

METHODS

A 62-year-old man complaining of blurred vision without apparent cause on clinical examination underwent keratometry and computerized corneal topography, which revealed superior corneal steepening in both eyes. Bilateral upper eyelid blepharoptosis surgery was performed.

RESULTS

Three months after blepharoptosis surgery, repeat computerized corneal topography revealed normal corneal contours with improved vision in both eyes.

CONCLUSIONS

Blepharoptosis is a common condition that may induce superior corneal ectasia that is not evident by manifest refraction, slit-lamp examination, or keratometry. Computerized corneal topography can help detect such subtle corneal abnormalities and guide therapy.

Embryonic expression of the human GATA-3 gene

The spatial and temporal analysis of GATA-3 expression pattern in the human embryo revealed its expression in new anatomical sites. These include the endoderm of the primitive foregut, pharynx and allantois, the branchial arches and the mesenchymal cells surrounding the stomach and dorsal aorta. On the other hand, human (h) GATA-3 expression in the central nervous system, somites and embryonic kidney confirms the tissue specificity of this gene throughout vertebrate evolution.

Differential expression of KDR/VEGFR-2 and CD34 during mesoderm development of the early human embryo

Recent findings on vertebrate embryos have provided compelling evidence for the existence of hemangioblasts, i.e. common precursors for endothelial and hematopoietic cells, characterized by expression of the VEGFR2/Flk1 receptor. We describe here a population of KDR+ CD34- mesoderm cells that emerges in early-somitic human embryos, by the beginning of the 4th week of gestation. In the developing blood vessels, KDR-expressing CD34- cells gradually coexpress increasing levels of CD34 antigen. Remarkably, as development proceeds, a KDR+ CD34- contingent persists in the paraaortic splanchnopleura until just prior to the emergence of aorta-associated hematopoietic cell clusters. These observations suggest that KDR+ CD34- mesodermal cells might represent the putative hemangioblastic precursor of human hematopoietic and endothelial lineages.

Melanotransferrin gene expression in melanoma cells is correlated with high levels of Jun/Fos family transcripts and with the presence of a specific AP1-dependent ternary complex

The involvement of the transcription factor AP1 in the regulation of melanotransferrin (MTf) gene expression was investigated. MTf, also known as p97, is a tumour-associated antigen that is overproduced in most melanomas. Its gene expression is under the control of an enhancer element containing two AP1 binding sites. By Northern analysis, we demonstrate that MTf mRNA is detected at various levels in melanoma SK-MEL-28 cells and that its greatest expression coincides with the presence of large amounts of jun and fos transcripts. Gel retardation assays revealed that the induction of expression of these proto-oncogenes is correlated with increased AP1 binding activity and that a region of the MTf enhancer is involved in the formation of a ternary AP1-dependent complex, implicating a second nuclear factor whose binding characteristics are similar to those of nuclear factor of activated T cells (NF-AT). In transient expression experiments, the activity resulting from ternary complex formation was high and specific to melanoma cells. These data provide a possible explanation for the mechanisms of AP1 factor family involvement in MTf up-regulation in melanoma cells.