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Automated Measurement of Microcirculatory Blood Flow Velocity in Pulmonary Metastases of Rats

Because the lung is a major target organ of metastatic disease, animal models to study the physiology of pulmonary metastases are of great importance. ...

Duke University Medical Center

Carpal tunnel syndrome is a common compression neuropathy of the median nerve. Acute carpal tunnel syndrome (aCTS) is rare, associated with a variety of conditions. In this case report we present a patient who developed aCTS and volar forearm compartment syndrome after a radial artery line placement, while receiving intravenous heparin. The patient underwent immediate forearm fasciotomy and surgical release for restoration of nerve function, which resulted in improved hand function and mild residual median nerve neuropathy. There is controversy whether to discontinue or not anticoagulation in a patient with aCTS. In our patient, heparin therapy was restarted on the second postoperative day.

Acute carpal tunnel syndrome secondary to iatrogenic hemorrhage. A case report.

Intravital microscopy of the pulmonary microcirculation in research animals is of great scientific interest for its utility in identifying regional changes in pulmonary microcirculatory blood flow. Although feasibility studies have been reported, the pulmonary window can be further refined into a practical tool for pharmaceutical research and drug development. We have established a method to visualize and quantify dynamic changes in three key features of lung function: microvascular red blood cell velocity, flow direction, and hemoglobin saturation. These physiological parameters were measured in an acute closed-chest pulmonary window, which allows real-time images to be captured by fluorescence and multispectral absorption microscopy; images were subsequently quantified using computerized analysis. We validated the model by quantifying changes in microcirculatory blood flow and hemoglobin saturation in two ways: 1) after changes in inspired oxygen content and 2) after pharmacological reduction of pulmonary blood flow via treatment with the β1 adrenergic receptor blocker metoprolol. This robust and relatively simple system facilitates pulmonary intravital microscopy in laboratory rats for pharmacological and physiological research.

Automated measurement of blood flow velocity and direction and hemoglobin oxygen saturation in the rat lung using intravital microscopy.

Free vascularized fibular transfer has become a standard procedure in upper extremity reconstruction after resection of osteogenic tumors. The authors present two rare pediatric cases of high-grade osteosarcoma resection of the proximal humerus. A free vascularized fibula autograft including the physis based on the anterior tibial artery and vein was used for reconstruction in a delayed (case 1) and immediate (case 2) approach. The main focus of the article is to describe the surgical technique, which is also presented in a series of intraoperative videos.

Vascularized fibula-based physis transfer for pediatric proximal humerus reconstruction.

The transfer of patients with hand injuries involves a commitment of substantial resources, emphasizing the importance of understanding factors that may influence referral patterns. Anecdotal experience suggests that the likelihood of transfer increases during nights and weekends. This study aimed to analyze patterns of hand trauma transfers to Duke University Medical Center with respect to timing and patient insurance status.

Factors associated with transfer of hand injuries to a level 1 trauma center: a descriptive analysis of 1147 cases.

Rapid ascent to high altitude causes illness and fatigue, and there is a demand for effective acute treatments to alleviate such effects. We hypothesized that increased oxygen delivery to the tissue using a combination of a hypertensive agent and an endothelin receptor A antagonist drugs would limit exercise-induced fatigue at simulated high altitude. Our data showed that the combination of 0.1 mg/kg ambrisentan with either 20 mg/kg ephedrine or 10 mg/kg methylphenidate significantly improved exercise duration in rats at simulated altitude of 4,267 m, whereas the individual compounds did not. In normoxic, anesthetized rats, ephedrine alone and in combination with ambrisentan increased heart rate, peripheral blood flow, carotid and pulmonary arterial pressures, breathing rate, and vastus lateralis muscle oxygenation, but under inspired hypoxia, only the combination treatment significantly enhanced muscle oxygenation. Our results suggest that sympathomimetic agents combined with endothelin-A receptor blockers offset altitude-induced fatigue in rats by synergistically increasing the delivery rate of oxygen to hypoxic muscle by concomitantly augmenting perfusion pressure and improving capillary conductance in the skeletal muscle. Our findings might therefore serve as a basis to develop an effective treatment to prevent high-altitude illness and fatigue in humans.

Anti-hypotensive treatment and endothelin blockade synergistically antagonize exercise fatigue in rats under simulated high altitude.

Fracture stabilization in the diabetic patient is associated with higher complication rates, particularly infection and impaired wound healing, which can lead to major tissue damage, osteomyelitis, and higher amputation rates. With an increasing prevalence of diabetes and an aging population, the risks of infection of internal fixation devices are expected to grow. Although numerous retrospective clinical studies have identified a relationship between diabetes and infection, currently there are few animal models that have been used to investigate postoperative surgical-site infections associated with internal fixator implantation and diabetes. The authors therefore refined the protocol for inducing hyperglycemia and compared the bacterial burden in controls to pharmacologically induced type 1 diabetic rats after undergoing internal fracture plate fixation and Staphylococcus aureus surgical-site inoculation. Using an initial series of streptozotocin doses, followed by optional additional doses to reach a target blood glucose range of 300 to 600 mg/dl, the authors reliably induced diabetes in 100 percent of the rats (n = 16), in which a narrow hyperglycemic range was maintained 14 days after onset of diabetes (mean ± SEM, 466 ± 16 mg/dl; coefficient of variation, 0.15). With respect to their primary endpoint, the authors quantified a significantly higher infectious burden in inoculated diabetic animals (median, 3.2 × 10 colony-forming units/mg dry tissue) compared with inoculated nondiabetic animals (7.2 × 10 colony-forming units/mg dry tissue). These data support the authors' hypothesis that uncontrolled diabetes adversely affects the immune system's ability to clear Staphylococcus aureus associated with internal hardware.

Gert Blueschke

Division of Plastic,
Maxillofacial,
and Oral Surgery,
Division of Plastic, Maxillofacial, and Oral Surgery

Duke University Medical Center

Automated Measurement of Microcirculatory Blood Flow Velocity in Pulmonary Metastases of Rats

Gert Blueschke

Division of Plastic,Maxillofacial,and Oral Surgery,Division of Plastic, Maxillofacial, and Oral Surgery

Duke University Medical Center

Automated Measurement of Microcirculatory Blood Flow Velocity in Pulmonary Metastases of Rats

Division of Plastic,
Maxillofacial,
and Oral Surgery,
Division of Plastic, Maxillofacial, and Oral Surgery