High-resolution myocardial perfusion mapping in small animals in vivo by spin-labeling gradient-echo imaging.

An ECG and respiration-gated spin-labeling gradient-echo imaging technique is proposed for the quantitative and completely noninvasive measurement and mapping of myocardial perfusion in small animals in vivo. In contrast to snapshot FLASH imaging, the spatial resolution of the perfusion maps is not limited by the heart rate. A significant improvement in image quality is achieved by synchronizing the inversion pulse to the respiration movements of the animals, thereby allowing for spontaneous respiration. High-resolution myocardial perfusion maps (in-plane resolution=234 x 468 microm2) demonstrating the quality of the perfusion measurement were obtained at 4.7 T in a group of seven freely breathing Wistar-Kyoto rats under isoflurane anesthesia. The mean perfusion value (group average +/- SD) was 5.5 +/- 0.7 ml g(-1)min(-1). In four animals, myocardial perfusion was mapped and measured under cardiac dobutamine stress. Perfusion increased to 11.1 +/- 1.9 ml g(-1)min(-1). The proposed method is particularly useful for the study of small rodents at high fields.     

Menhaden fish oil, n-3 polyunsaturated fatty acids, and protection of newborn rats from oxygen toxicity

We have previously reported that newborn rats born to mothers fed a high n-6 polyunsaturated fatty acid (PUFA) (safflower oil) diet demonstrated increased n-6 PUFA in lung lipids and superior tolerance to high oxygen exposure. In the present study, we explored whether high n-3 PUFA might also protect against hyperoxic damage and by what mechanism. Adult female rats were fed either regular rat chow, a high n-3 (menhaden fish oil-based) diet, or a high n-6 (safflower oil-based) diet for 6 wk before and then throughout pregnancy and lactation. Newborn offspring of the high n-3 (fish oil) dams demonstrated increased n-3 PUFA (i.e. eicosapentaenoic and docosahexaenoic acid) and decreased n-6 PUFA (i.e. linoleic and arachidonic acid) in their lung lipids compared to the other two diet groups. The high n-6 (safflower oil) offspring had the opposite PUFA lung lipid pattern (with increases in total n-6 fatty acids and decreases in total n-3 fatty acids). The high n-3 offspring demonstrated markedly decreased lung levels of prostaglandin E2, F2 alpha and thromboxane B2, whereas the high n-6 offspring had higher eicosanoid levels than the regular diet offspring. Offspring of both high n-6 and high n-3 diet dams demonstrated essentially the same superior hyperoxic tolerance compared to regular diet offspring [7-d (greater than 95% O2) survival rates of 110/115 and 99/109, respectively, versus 70/91, p less than 0.01].(ABSTRACT TRUNCATED AT 250 WORDS)     

Characterization of normal and infarcted rat myocardium using a combination of small-animal PET and clinical MRI.

The combination of small-animal PET and MRI data provides quantitative in vivo insights into cardiac pathophysiology, integrating information on biology and morphology. We sought to determine the feasibility of PET and MRI for the quantification of ischemic injury in the rat model. METHODS: Fourteen healthy male Wistar rats were studied with 18F-FDG PET and cine MRI. Myocardial viability was determined in a transmural myocardial infarction model in 12 additional rats, using 18F-FDG PET and delayed-enhancement MRI with gadolinium-diethylenetriaminepentaacetic acid. All PET was acquired with a dedicated small-animal PET system. MRI was performed on a 1.5-T clinical tomograph with a dedicated small-animal electrocardiographic triggering device and a small surface coil. RESULTS: In normal rats, 18F-FDG uptake was homogeneous throughout the left ventricle. The lowest mean uptake of the 18F-FDG was found in the apical regions (79% +/- 6.0% of maximum) and the highest uptake was in the anterior wall (93% +/- 4.3 % of maximum). Myocardial infarct size as determined by histology correlated well with defects of glucose metabolism obtained with 18F-FDG PET (r = 0.89) and also with delayed-enhancement MRI (r = 0.91). Left ventricular ejection fraction in normal rats measured by cine MRI was 57% +/- 5.4% and decreased to 38% +/- 12.9% (P < 0.001) in the myocardial infarction model. CONCLUSION: Integrating information from small-animal PET and clinical MRI instrumentation allows for the quantitative assessment of cardiac function and infarct size in the rat model. The MRI measurements of scar can be complemented by metabolic imaging, addressing the extent and severity of ischemic injury and providing endpoints for therapeutic interventions.     

Hybrid Anterior Cruciate Ligament Reconstruction: Introduction of a New Technique for Anatomic Anterior Cruciate Ligament Reconstruction

Recently, anatomic or double-bundle reconstruction of the anterior cruciate ligament (ACL) has been presented in an effort to more accurately restore the native anatomy. These techniques create 2 tunnels in both the femur and tibia to reproduce the bundles of the ACL. However, the increased number of tunnels, particularly on the femoral side, has raised some concerns among authors and surgeons. We describe a technique to reconstruct the 2 distinct bundles of the ACL by using a single femoral tunnel and 2 tibial tunnels, the “hybrid” ACL reconstruction. The femoral tunnel is drilled through an anteromedial arthroscopy portal, which allows placement in a more anatomic position. Fixation in the femur is achieved with a novel device that separates a soft-tissue graft into 2 independently functioning bundles. Once fixed in the femur, the anteromedial and posterolateral bundles of the graft are passed through respective tunnels at the anatomic footprint on the tibia. These bundles are independently tensioned, which creates a reconconstruction that is similar to the native ACL. The technique presented provides surgeons with an alternative to other double-bundle techniques involving 4 tunnels.     

Advanced surgical techniques to enhance implant success in the maxilla.

While less emphasis has traditionally been placed on aesthetics in order to focus on successful osseointegration, increased success rates provided by contemporary endosseous root-form dental implants have improved postoperative peri-implant hard and soft tissue structures. The criteria for the evaluation of implant success should, therefore, include lack of pain, mobility, radiolucency, bone loss, infection, or paresthesia, as well as acceptability and stable aesthetics. This article discusses surgical means to preserve or restore hard and soft tissues around dental implants to achieve ideal and predictable outcomes.     

Best-practice algorithms for the use of a bilayered living cell therapy (Apligraf®) in the treatment of lower-extremity ulcers

Tissue-engineered skin substitutes such as Apligraf have emerged over the past 20 years as among the most carefully studied and efficacious of the advanced wound modalities. These products have been proven as effective enhancements to general wound care, promoting wound closure particularly in instances where conventional wound care fails. Marketed for hard-to-heal wounds since 1998, Apligraf has become part of standard wound care in many wound centers across the United States. Despite this situation, few general wound care guidelines incorporate advanced and active wound-healing technologies, such as tissue-engineered skin products. Because of this deficiency, appropriate patient selection and proper use of these product remain largely unaddressed within the general wound care community. Here, we describe the development of guidelines surrounding optimal use of the bilayered living cell therapy, Apligraf, in the treatment of the two types of lower extremity ulcers for which the product is FDA approved: venous leg ulcer and diabetic foot ulcer. The guidelines detailed in this article focus on the identification and selection of patients who are at risk for failure of standard wound care therapy and thus appropriate for Apligraf treatment. The intended audience for these guidelines is the general wound care practitioner, for whom the developed treatment algorithms and accompanying figure legends should provide practical, user-friendly direction simplifying both patient selection and appropriate use of Apligraf within the context of good wound-healing practice.     

SHELLFISH GATHERING IN KIRIBATI, MICRONESIA: NUTRITIONAL, MICROBIOLOGICAL, AND TOXICOLOGICAL ASPECTS

Shellfish gathering has received comparatively little attention in the anthropological literature. Yet, the contribution of shellfish to the diet of indigenous societies can be significant. Reef and lagoon gleaning activities in Kiribati, Micronesia illustrate the importance of this class of invertebrates, particularly on urban South Tarawa. Proximate composition of 24 bivalves and gastropods add to our knowledge of the nutritional value of tropical shellfish. Microbiological contamination remains a problem, however, notably among inshore shellfish collected from Tarawa Lagoon. Assays on one species of cowrie (Cypraea tigris) confirm its toxicological properties, as suggested by some informants. The future of shellfish resources in Kiribati will need to address the issue of open access associated with an erosion of customary marine tenure.     

Delayed osteotomy but not fracture healing in pediatric osteogenesis imperfecta patients receiving pamidronate.

This study evaluated factors influencing fracture (n = 197) and osteotomy (n = 200) healing in children with moderate to severe OI. Pamidronate treatment was associated with delayed healing after osteotomy, but not after fracture. The data suggest that both pamidronate and mechanical factors influence bone healing in this cohort. INTRODUCTION: Intravenous pamidronate is widely used to treat children with moderate to severe osteogenesis imperfecta (OI). However, the effect of this treatment on bone healing is not well characterized. We therefore retrospectively analyzed the healing of lower limb fractures and osteotomies in children with moderate to severe OI, both before and after the start of pamidronate treatment. MATERIALS AND METHODS: Bone healing was evaluated on standard radiographs after 197 lower limb fractures (132 femur and 65 tibia) in 82 patients (age at fracture, 0.0-19.9 years) and 200 intramedullary rodding procedures in 79 patients (age at surgery, 1.2-19.8 years). Delayed healing was diagnosed when a fracture or osteotomy line was at least partially visible 12 months after the event. RESULTS: Delayed fracture healing was observed more frequently during than before pamidronate treatment. However, the effect of pamidronate was no longer significant when age differences were taken into account (odds ratio [OR], 1.76; 95% CI, 0.61-5.10). Better mobility status was a strong independent predictor of delayed healing after fractures that occurred during pamidronate treatment. After osteotomies, delayed healing was more frequent when pamidronate had been started before surgery (OR, 7.29; 95% CI, 2.62-20.3), and this effect persisted after adjustment for multiple confounders. During pamidronate treatment, older age (OR per year of age, 1.25; 95% CI, 1.06-1.47) and osteotomy of the tibia (OR, 3.51; 95% CI, 1.57-7.82) were independent predictors of delayed healing. CONCLUSIONS: This study suggests that pamidronate therapy is associated with delayed healing of osteotomy sites after intramedullary rodding procedures. Better mobility status, but not pamidronate treatment, seems to be predictive of delayed healing after fractures.