Myocardial metabolism and regional myocardial blood flow in the canine left ventricle following twenty minutes of circumflex artery occlusion and reperfusion

The recovery of high energy phosphate stores (ATP plus phosphocreatine) was examined following various periods of reperfusion after 20 min circumflex artery occlusion in the open-chest dog. Transmural tissue samples were obtained from the posterior wall of the left ventricle of control dogs, after 20 min occlusion and after 1, 5, 10, 15 and 20 min reperfusion. Significant reductions in high energy phosphate stores were observed in the subepicardium (41.6% of control) and subendocardium (31.3% of control) after occlusion. Upon reperfusion, recovery was rapid and exceeded control by 65.4% (91.0 v. 55.0 μm/g dry wt) in the subendocardium, but only by 2.6% (72.2 v. 70.4, μmg/g dry wt) in the subepicardium and was due mainly to recovery of phosphocreatine. Regional myocardial blood flow was studied in a separate, but identical, series of experiments. During occlusion, posterior wall blood flow was reduced by 54% (0.85 ± 0.04 to 0.37 ± 0.04, ml/g/min) in the subepicardium and by 94.7% (1.13 ± 0.05 to 0.06 ± 0.005, ml/g/min) in the subendocardium. Reperfusion produced a rapid recovery including overshoot of blood flow compared to control blood flow. Peak blood flow occurred one minute after release of the occlusion becoming 3.34 ± 0.16 ml/g/min in the subepicardium and 2.39 ± 0.13 ml/g/min in the subendocardium. Blood flow in both levels returned to control flow after 15 min reperfusion. These results indicate that metabolic recovery of high energy phosphate stores occurred within 5 min of restoration of blood flow in this model.     

Detection of plasminogen activators in oral cancer by laser capture microdissection combined with zymography

Plasminogen activation is believed to be critical to the progression of oral squamous cell carcinoma by facilitating matrix degradation during invasion and metastasis, and high levels of urokinase plasminogen activator (uPA) and plasminogen activator (PA) inhibitor-1 (PAI-1) in tumors predict poor disease outcome. We describe the development of a novel method for studying PA in oral cancer that combines the sensitivity and specificity of zymography with the spatial resolution of immunohistochemistry. Laser capture microdissection (LCM) was combined with plasminogen–casein zymography to analyze uPA, tissue PA (tPA), uPA–PAI-1 complexes, and tPA–PAI-1 complexes in 11 tumors and adjacent non-malignant epithelium from squamous cell carcinomas of the tongue, floor of mouth, larynx, and vocal cord. uPA was detectable in all tumor samples analyzed, uPA–PAI-1 complexes in three samples, and tPA in nine. PA was detectable in as little as 0.5 μg protein lysate from microdissected tumors. In all specimens, uPA expression was highly increased in tumor tissue compared to adjacent non-malignant tissue. In conclusion, LCM combined with zymography may be excellently suited for analyzing the prognostic significance and causal involvement of the plasminogen activation system in oral cancer.     

The importance of phase-encoding order in ultra-short TR snapshot MR imaging

We show the importance of phase-encoding order in ultra-short TR (less than 10 ms) snapshot MR imaging. Contrast is more heavily dictated by the contrast preparation phase early in the measurement phase than later. When the low spatial frequencies are measured first, the resultant image contrast more closely resembles that established by the preparation phase. The transient nature of the data acquisition causes a kappa-space filter to be applied to the data. The effects of this filter can be minimized by appropriate choice of scan parameters.     

Challenges in molecular imaging of Parkinson's disease: a brief overview

Positron emission tomography (PET) is a sensitive and specific non-invasive molecular imaging technique providing quantitative images and data on biochemical pathways, molecular interactions, drug pharmacokinetics and pharmacodynamics. The PET measurement of regional biochemical functions requires a rational design of the radiolabelled probes employed. When choosing a drug to radiolabel there are many considerations, the most important being the potential of the drug to provide the information that is required in vivo. For example, when developing a radiolabelled probe for measuring the regional concentration of a neurotransmitter receptor the affinity and selectivity of the drug need to be considered. Other factors which influence a decision about which drug to radiolabel include the ability of the drug to reach its target, drug lipophilicity and metabolism, toxicity and the amenability to radiolabelling. PET has been applied in studies of Parkinson's disease (PD) and has provided important information on disease on-set and progression. This brief overview aims to outline the challenges and capabilities of PET and the more commonly used molecular probes in PD studies.     

Maxillary osteosarcoma associated with a dental implant: report of a case and review of the literature regarding implant-related sarcomas

BACKGROUND: The development of malignant neoplasms has been reported as a rare complication of the use of implanted biomaterials. The majority of these cases have been sarcomas related to orthopedic hardware. The authors present the first reported case of a sarcoma arising in association with a dental implant. CASE DESCRIPTION: A 38-year-old woman developed a low-grade chondroblastic osteosarcoma of the right maxilla 11 months after receiving a titanium dental implant. She was treated with systemic chemotherapy and then a maxillary resection. As of this publication, 47 months later, she is alive and disease-free. CLINICAL IMPLICATIONS: The use of endosseous implants has been associated with a low risk for the development of cancer. As the use of dental implants continues to expand, dentists need to be aware of this rare but devastating complication.