Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography

The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study.     

Epididymal protein CRISP1 plays different roles during the fertilization process

Rat epididymal CRISP1, the first described member of the evolutionarily conserved Cysteine-RIch Secretory Protein (CRISP) family, is expressed in the proximal regions of the epididymis and associates with the sperm during epididymal transit. Evidence indicates the existence of 2 populations of CRISP1 in spermatozoa: a major one, loosely bound, which is released during capacitation and, therefore, proposed as a decapacitating factor; and a minor one, strongly associated with spermatozoa that remains on the cells after capacitation and is proposed to participate in gamete interaction. Originally localized to the dorsal region of capacitated sperm, CRISP1 migrates to the equatorial segment with capacitation and acrosome reaction. Consistent with these localizations, in vitro fertilization experiments support the involvement of CRISP1 in the first step of sperm-zona pellucida (ZP) interaction and subsequent gamete fusion through its interaction with egg-complementary sites. The potential roles of CRISP1 in capacitation and fertilization have been further supported by the finding that capacitated spermatozoa from CRISP1 "knockout" animals exhibit low levels of protein tyrosine phosphorylation and have an impaired ability to fertilize zona-intact and zona-free eggs in vitro. Moreover, recent evidence from mutant spermatozoa reveals that CRISP1 mediates the stage of sperm binding to the ZP. Altogether, these observations support the view that CRISP1 is a multifunctional protein playing different roles during fertilization through its different associations with and localizations on spermatozoa. We believe these results contribute to a better understanding of the molecular mechanisms involved in both the fertilization process and the acquisition of sperm-fertilizing ability that occurs during epididymal maturation.     

Proteolytic processing of osteopontin by PHEX and accumulation of osteopontin fragments in Hyp mouse bone,the murine model of X‐linked hypophosphatemia

X‐linked hypophosphatemia (XLH/HYP)—with renal phosphate wasting, hypophosphatemia, osteomalacia, and tooth abscesses—is caused by mutations in the zinc‐metallopeptidase PHEX gene (phosphate‐regulating gene with homologies to endopeptidase on the X chromosome). PHEX is highly expressed by mineralized tissue cells. Inactivating mutations in PHEX lead to distal renal effects (implying accumulation of a secreted, circulating phosphaturic factor) and accumulation in bone and teeth of mineralization‐inhibiting, acidic serine‐ and aspartate‐rich motif (ASARM)‐containing peptides, which are proteolytically derived from the mineral‐binding matrix proteins of the SIBLING family (small, integrin‐binding ligand N‐linked glycoproteins). Although the latter observation suggests a local, direct matrix effect for PHEX, its physiologically relevant substrate protein(s) have not been identified. Here, we investigated two SIBLING proteins containing the ASARM motif—osteopontin (OPN) and bone sialoprotein (BSP)—as potential substrates for PHEX. Using cleavage assays, gel electrophoresis, and mass spectrometry, we report that OPN is a full‐length protein substrate for PHEX. Degradation of OPN was essentially complete, including hydrolysis of the ASARM motif, resulting in only very small residual fragments. Western blotting of Hyp (the murine homolog of human XLH) mouse bone extracts having no PHEX activity clearly showed accumulation of an ～35 kDa OPN fragment that was not present in wild‐type mouse bone. Immunohistochemistry and immunogold labeling (electron microscopy) for OPN in Hyp bone likewise showed an accumulation of OPN and/or its fragments compared with normal wild‐type bone. Incubation of Hyp mouse bone extracts with PHEX resulted in the complete degradation of these fragments. In conclusion, these results identify full‐length OPN and its fragments as novel, physiologically relevant substrates for PHEX, suggesting that accumulation of mineralization‐inhibiting OPN fragments may contribute to the mineralization defect seen in the osteomalacic bone characteristic of XLH/HYP. © 2013 American Society for Bone and Mineral Research.     

Whole‐body diffusion‐weighted imaging with a continuously moving table acquisition method: Preliminary results

In this study, a method for whole‐body diffusion‐weighted imaging (wbDWI) during continuous table motion has been developed and implemented on a clinical scanner based on a short‐Tau inversion recovery echo‐planar DWI sequence. Unlike currently available multistation wbDWI, which has disadvantages such as long scanning times, poor image quality, and troublesome data realignment, continuously moving table wbDWI can overcome these technical problems while extending the longitudinal field of view in MRI systems. In continuously moving table wbDWI, images are acquired consecutively at the isocenter of the magnet, having less geometric distortions and various possibilities of spatial and temporal coverage of an extended field of view. The acquired images, together with an apparent diffusion coefficient analysis, show that continuously moving table wbDWI can be used by appropriately adapting the table velocity, scan range, radiofrequency coils, slice resolutions, and spatio‐temporal acquisition schemes according to various clinical demands. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.     

Minimally Invasive Approach to Esophagectomy

Background:

Recent advances in laparoscopic and thoracoscopic surgery have made it possible to perform esophagectomy using minimally invasive techniques. The aim of this report was to present our preliminary experience with minimally invasive esophagectomy.

Methods:

We reviewed our experience on eight patients who underwent minimally invasive esophagectomy using either laparoscopic and/or thoracoscopic techniques from June 1996 to May 1997. Indications for esophagectomy included stage I carcinoma (5), palliative resection (1), Barrett''s with high grade dysplasia (1) and end stage achalasia (1).

Results:

The average age was 68 years (54-82). The surgical approach to esophagectomy included laparoscopic transhiatal esophagectomy with cervical anastomosis (n=4), thoracoscopic and laparoscopic esophagectomy with cervical anastomosis (n=1), and laparoscopic mobilization with right mini-thoracotomy and intra-thoracic anastomosis (n=3). Conversion to mini-laparotomy was required in two patients (25%) to complete esophageal dissection and facilitate gastric pull-up. The mean operative time was 460 minutes. The mean intensive care stay was 1.9 days (range of 0-7 days) with a mean hospital stay of 13-8 days. Minor complications included atrial fibrillation (n=1), pleural effusion (n=2) and persistent air leak (n=1). Major complications included cervical anastomotic leak (n=1), and delayed gastric emptying requiring pyloroplasty (n=1). There was no perioperative mortality.

Conclusions:

This preliminary experience suggests that minimally invasive esophagectomy is safe and feasible in centers with experience in advanced minimally invasive surgical procedures. Further studies are necessary to determine advantages over open esophagectomy.     

Recombinant human thyrotropin (rhTSH) in the management of differentiated thyroid cancer

Recombinant human thyrotropin (rhTSH) has been evaluated in 38 patients with differentiated thyroid cancer. The patients had all been treated previously by operation and 31 had received radioiodine 131I. The patients continued to take thyroid hormone and changed to a low iodine diet for 14 days before and throughout the week of testing. The rhTSH was injected intramuscularly on two consecutive days, 74 MBq 131I was administered on the next day and scintigraphy completed 48 h after that. TSH was measured before administration of 131I, and thyroglobulin after the scan. All patients preferred this method to withdrawal of thyroid hormone, but 45% had mild symptoms including headache and nausea. The average TSH was 127 mU x l(-1), and was inversely related to the weight of the patients. Thirty-four had negative scans with a mean uptake of 0.06%. Thyroglobulin values above 10 ng x ml(-1) were found in seven patients, of whom four had similar findings when scanned after withdrawal of thyroid hormone. Of four with positive scans, two had undetectable thyroglobulin. The rate of clearance of 131I was compared in patients studied at 72 h who were hypothyroid and at 48 h in euthyroid patients given rhTSH and was found to be longer in the latter. We conclude that rhTSH can be used to stimulate thyroid tissue to trap 131I and secrete thyroglobulin. Both scan and thyroglobulin should be obtained. The method is well tolerated.     

Surgical management of symptomatic spinal metastases. Postoperative outcome and quality of life

STUDY DESIGN: Eighty-six surgical interventions in 76 consecutive patients with symptomatic spinal metastases were reviewed retrospectively. OBJECTIVES: To evaluate the postoperative outcome and quality of life of patients surgically treated for symptomatic spinal metastases. SUMMARY OF BACKGROUND DATA: The standard surgical treatment for patients with symptomatic spinal metastases is anterior spinal cord decompression with stabilization. However, because therapy is only palliative, satisfactory quality of life and high patient acceptance are essential. METHODS: The medical records of all patients were reviewed retrospectively. Furthermore, all surviving patients or the next of kin of deceased patients were interviewed by telephone, and the family doctors or the care-providing physicians of external institutions were contacted. RESULTS: First-choice surgical treatment was anterior spinal cord decompression with stabilization. Postoperative mean survival was 13.1 months, and mean time at home after spinal surgery was 11.1 months. Neurologic improvement with regard to Frankel classification was observed in 58% of the patients, and 93% were able to walk postoperatively. Pain relief was noted in 89%. Overall, 67% of the patients achieved moderate or good general health as shown by the Karnofsky Index, and 80% were satisfied or very satisfied with the surgical intervention. Moreover, 19% of the surgical interventions were associated with complications, local tumor recurrence developed in 22% of the patients, and paraplegia ultimately developed in 18% of patients. CONCLUSIONS: Surgical management of symptomatic spinal metastases, in particular anterior decompression, is of benefit in most metastatic lesions in terms of satisfactory postoperative outcome and quality of life. However, in patients with melanoma or lung carcinoma, the authors advocate spinal surgery only in very exceptional cases.