NO,iNOS与胃癌关系的研究进展

幽门螺杆菌(H.pylori)感染造成的炎症反应,可刺激诱导型NO合酶(inducible NO synthase,iNOS)产生大量的NO,对胃癌的启动和发展起重要作用.进入20世纪90年代以来,一氧化氮(NO)研究跨入了迅猛发展的阶段,许多调节功能及其在病理生理过程中所起的重要作用被逐渐认识,特别是NO在致癌和致突变过程中表现的双重性,更是近年的研究热点之一[1,2].本文就NO、iNOS与胃癌关系的研究进展作一综述.     

Prevalence,biological phenotype and genotype in moderate/mild hemophilia A with discrepancy between one‐stage and chromogenic factor VIII activity

Summary. Background: In most laboratories, the severity of hemophilia A is assessed by the factor VIII activity (FVIII:C) one‐stage assay. However, comparisons of these results with those of two‐stage assays can reveal discrepancies and suggest misdiagnosis. Patients/Methods: In this monocentric study, we measured FVIII:C with two methods (one‐stage chronometric and chromogenic assays) in 307 (173 families) patients with moderate/mild hemophilia A. To compare results, we used a chronometric/chromogenic ratio. Discrepancy was defined as a ratio < 0.5 or > 1.5. We studied their putative involvement at known FVIII functional sites, their interspecies conservation status, and their spatial position within the FVIII structure. Results: Thirty‐six patients from 17 families exhibited a discrepancy between the two assays: 12 (6.9%) families had a low ratio (< 0.5), and five (2.9%) families had a high ratio (> 1.5). Qualitative deficiency was diagnosed in about 16% of the families. Molecular studies were performed in 15 of these 17 families, resulting in each case in the identification of missense mutations, including three novel mutations. We were further able to propose a pathophysiologic explanation. Conclusions: In this monocentric study, we have demonstrated a discrepancy between FVIII:C assay results in 10% of families with moderate/mild hemophilia A. The prevalence of ‘inverse’ discrepancy (i.e. low chronometric/chromogenic ratio) is high as compared with previous reports. We suggest that both FVIII:C assays are recommended in patients with moderate/mild hemophilia A for a complete biological phenotype. This could also improve our knowledge of the FVIII structure–function relationships.     

A technique to access difficult to find upper extremity veins for right heart catheterization: The levogram technique

Upper extremity venous access provides a safer alternative for performance of right heart catheterization compared to femoral venous access. We describe a technique to access deep veins of the upper extremity, in patients undergoing transradial catheterization, using levophase contrast venography. This technique allows the operator to access deep veins of the upper extremity without the need for additional equipment, staff or training, using traditional basic catheterization laboratory skills and equipment. © 2011 Wiley‐Liss, Inc.     

A method for maintaining vascular access when Impella exchange is required

A 45‐year old male with no prior cardiac history, presented with cardiogenic shock in the setting of an anterolateral ST elevation myocardial infarction. We first placed a 2.5 Impella for hemodynamic support, and proceeded with emergent percutaneous coronary intervention to the proximal LAD. Several hours following percutaneous coronary intervention (PCI), the patient became acutely hypotensive and an echocardiogram revealed the Impella catheter was kinked within the left ventricle. The patient was taken back to the cath lab for Impella adjustment; however, damage to the distal catheter required the Impella be exchanged. As the patient was therapeutically anticoagulated and on dual antiplatelet therapy, we modified the Impella catheter in order to maintain existing vascular access during Impella exchange. This case demonstrates our method for maintaining vascular access during Impella exchange, thereby eliminating the need for a second arterial puncture. © 2017 Wiley Periodicals, Inc.     

Motion artifact reduction of diffusion‐weighted MRI of the liver: Use of velocity‐compensated diffusion gradients combined with tetrahedral gradients

Purpose:

To assess the effect of motion artifact reduction on the diffusion‐weighted magnetic resonance imaging (DWI‐MRI) of the liver, we compared velocity‐compensated DWI (VC‐DWI) and VC‐DWI combined with tetrahedral gradients (t‐VC‐DWI) to conventional DWI (c‐DWI) in the assessment of apparent diffusion coefficients (ADCs) of the liver.

Materials and Methods:

In 12 healthy volunteers, the liver was scanned with c‐DWI, VC‐DWI, and t‐VC‐DWI sequences. The signal‐to‐noise ratio (SNR) and ADC of the liver parenchyma were measured and compared among sequences.

Results:

The image quality was visually better for t‐VC‐DWI than for the others. The SNR for t‐VC‐DWI was significantly higher than that for VC‐DWI (P < 0.05) and comparable to that for c‐DWI. ADCs in both hepatic lobes were significantly lower for t‐VC‐DWI than for c‐DWI (P < 0.01). ADC in the left lobe was significantly lower for VC‐DWI than for c‐DWI (P < 0.01). Although ADC in the left lobe was significantly higher for c‐DWI (P < 0.01), no significant differences in ADCs were found between the right and left lobes for VC‐DWI and t‐VC‐DWI.

Conclusion:

The use of a t‐VC‐DWI sequence enables us to correct ADCs of the liver for artificial elevation due to cardiac motion, with preserved SNR. J. Magn. Reson. Imaging 2013;37:172–178. © 2012 Wiley Periodicals, Inc.     

ACR guidance document on MR safe practices: 2013

Because there are many potential risks in the MR environment and reports of adverse incidents involving patients, equipment and personnel, the need for a guidance document on MR safe practices emerged. Initially published in 2002, the ACR MR Safe Practices Guidelines established de facto industry standards for safe and responsible practices in clinical and research MR environments. As the MR industry changes the document is reviewed, modified and updated. The most recent version will reflect these changes. J. Magn. Reson. Imaging 2013;37:501–530. © 2013 Wiley Periodicals, Inc.     

The prognostic value of transient ischemic dilatation with otherwise normal SPECT myocardial perfusion imaging: A cautionary note in patients with diabetes and coronary artery disease

Background

The prognostic implications of transient ischemic dilatation (TID) of the left ventricle with otherwise normal single-photon emission computed tomography myocardial perfusion imaging (MPI) remain controversial. Whether this finding may have prognostic implications only in high-risk populations, such as patients with diabetes or manifest coronary artery disease (CAD), is uncertain.

Methods

We conducted a prospective cohort study of 1,236 consecutive patients with normal ^99mTc-sestamibi MPI, defined as normal perfusion (summed stress score = 0) and normal left ventricle volume and function. TID was defined as >2 standard deviations above the mean of patients with low likelihood of CAD.

Results

The study subjects were followed for 27 ± 9 months. The 76 (6%) patients with TID had a greater rate of cardiac death or myocardial infarction (MI) [4 (5.3%) vs 11 (0.6%), P = .003] independent of covariates [hazard ratio = 6.4, P = .004]. This finding was entirely derived from the subgroup of 294 patients with diabetes or CAD [4 (13.3%) with TID vs 1 (0.4%) without TID, P = .001] independent of covariates. However, TID was not predictive of cardiac death or MI among the 941 patients without diabetes or CAD. Furthermore, TID was not predictive of coronary revascularization.

Conclusions

This study confirms a benign prognosis of TID with otherwise normal MPI in patients without diabetes or CAD, but cautions against extending this conclusion to high-risk individuals, particularly those with diabetes or CAD.