Citations

The vasodilator signals regulating muscle blood flow during exercise are unclear. We tested the hypothesis that in young adults leg muscle vasodilation during steady-state exercise would be reduced independently by sequential pharmacological inhibition of nitric oxide synthase (NOS) and cyclooxygenase (COX) with NG-nitro-l-arginine methyl ester (l-NAME) and ketorolac, respectively. We tested a second hypothesis that NOS and COX inhibition would increase leg oxygen consumption (V̇o2) based on the reported inhibition of mitochondrial respiration by nitric oxide. In 13 young adults, we measured heart rate (ECG), blood pressure (femoral venous and arterial catheters), blood gases, and venous oxygen saturation (indwelling femoral venous oximeter) during prolonged (25 min) steady-state dynamic knee extension exercise (60 kick/min, 19 W). Leg blood flow (LBF) was determined by Doppler ultrasound of the femoral artery. Whole body V̇o2 was measured, and leg V̇o2 was calculated from blood gases and LBF. Resting intra-arterial infusions of acetylcholine (ACh) and nitroprusside (NTP) tested inhibitor efficacy. Leg vascular conductance (LVC) to ACh was reduced up to 53 ± 4% by l-NAME + ketorolac infusion, and the LVC responses to NTP were unaltered. Exercise increased LVC from 4 ± 1 to 33.1 ± 2 ml·min−1·mmHg−1 and tended to decrease after l-NAME infusion (31 ± 2 ml·min−1·mmHg−1, P = 0.09). With subsequent administration of ketorolac LVC decreased to 29.6 ± 2 ml·min−1·mmHg−1 ( P = 0.02; n = 9). While exercise continued, LVC returned to control values (33 ± 2 ml·min−1·mmHg−1) within 3 min, suggesting involvement of additional vasodilator mechanisms. In four additional subjects, LVC tended to decrease with l-NAME infusion alone ( P = 0.08) but did not demonstrate the transient recovery. Whole body and leg V̇o2 increased with exercise but were not altered by l-NAME or l-NAME + ketorolac. These data indicate a modest role for NOS- and COX-mediated vasodilation in the leg of exercising humans during prolonged steady-state exercise, which can be restored acutely. Furthermore, NOS and COX do not appear to influence muscle V̇o2 in untrained healthy young adults.

Background and Purpose— Recombinant Factor VIIa decreases hematoma growth after spontaneous intracerebral hemorrhage (ICH) and rapidly decreases international normalized ratios in patients on warfarin but is also associated with an increased risk for thromboembolic complications. In this study, we assessed the risk of thromboembolic events in patients receiving recombinant Factor VIIa after ICH associated with warfarin treatment. Methods— We reviewed the medical charts, laboratory data, and radiological findings of consecutive patients with anticoagulation-related hemorrhages of the central nervous system who received recombinant Factor VIIa at Mayo Clinic Rochester and Mayo Clinic Florida between 2002 and 2009. The primary end point was the frequency of new thromboembolic events, including myocardial infarction, deep vein thrombosis, ischemic stroke, and pulmonary embolism. Results— We identified 101 patients; 54% had ICH and 30% subdural hematomas. The most common indications for anticoagulation were atrial fibrillation, deep vein thrombosis, and prosthetic valve. Thirteen patients (12.8%) had new thromboembolic events (10 deep vein thromboses and 3 ischemic strokes) within 90 days after recombinant Factor VIIa administration. Eight of these adverse events occurred within 2 weeks of treatment. In patients with ICH, the rate of thromboembolic complications was 5% and all events were venous. Conclusion— The risk of thromboembolic events in patients who received recombinant Factor VIIa for anticoagulation-associated ICH was not higher than that seen in patients treated for spontaneous ICH in the Factor Seven for Acute Hemorrhagic Stroke (FAST) trial. Spontaneous deep vein thrombosis was the most common complication in our series.

AbstractThe antithrombotic surface of endothelium is regulated in a coordinated manner. Tissue factor pathway inhibitor (TFPI) localized at the endothelial cell surface regulates the production of FXa by inhibiting the TF/VIIa complex. Systemic homozygotic deletion of the first Kunitz (K1) domain of TFPI results in intrauterine lethality in mice. Here we define the cellular sources of TFPI and their role in development, hemostasis, and thrombosis using TFPI conditional knockout mice. We used a Cre-lox strategy and generated mice with a floxed exon 4 (TFPIFlox) which encodes for the TFPI-K1 domain. Mice bred into Tie2-Cre and LysM-Cre lines to delete TFPI-K1 in endothelial (TFPITie2) and myelomonocytic (TFPILysM) cells resulted in viable and fertile offspring. Plasma TFPI activity was reduced in the TFPITie2 (71% ± 0.9%, P < .001) and TFPILysM (19% ± 0.6%, P < .001) compared with TFPIFlox littermate controls. Tail and cuticle bleeding were unaffected. However, TFPITie2 mice but not TFPILysM mice had increased ferric chloride–induced arterial thrombosis. Taken together, the data reveal distinct roles for endothelial- and myelomonocytic-derived TFPI.

Abstract In a review of 417 intracranial astrocytomas treated radiotherapeutically at the Mayo Clinic from 1960 through 1969, the well-known correlation of tumor grade with survival was verified. Totally unexpected was the finding that age was fully as important a discriminant as tumor grade. Another unexpected finding was that patients treated with biopsy only followed by radiation therapy did as well as or slightly better than those subjected to resection followed by postoperative radiotherapy. We could not verify the importance to survival of either large dose or large volume radiotherapy, which has been emphasized by some. Patients receiving less than 1400 rets did just as well as or slightly better than those receiving more than 1400 rets. With low grade astrocytomas, survival beyond 4 years was significantly worse (higher death rates) in the group receiving more than 1400 rets. This suggested the possibility of radiation damage with delayed manifestations. We also could not verify an increased effectiveness for the generally accepted use of total brain irradiation for high grade gliomas.

Presented are the efforts of the Pharmaceutical Research and Manufacturing Association PFS Working Group to address concerns related to blinded independent central review of locally evaluated progression times and the proposed audit methodology to minimize potential biases, along with the U.S. Food and Drug Administration's comments on this work.