Transport of colloidal particles in lymphatics and vasculature after subcutaneous injection.
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This study was designed to determine the transport of subcutaneously injected viral-size colloid particles into the lymph and the vascular system in the hind leg of the dog. Transport of two colloid particles, with average size approximately 1 and 0.41 microm, respectively, and with and without leg rotation, was tested. Leg rotation serves to enhance the lymph flow rates. The right femoral vein, lymph vessel, and left femoral artery were cannulated while the animal was under anesthesia, and samples were collected at regular intervals after subcutaneous injection of the particles at the right knee level. The number of particles in the samples were counted under fluorescence microscopy by using a hemocytometer. With and without leg rotation, both particle sets were rapidly taken up into the venous blood and into the lymph fluid. The number of particles carried away from the injection site within the first 5 min was <5% of the injected pool. Particles were also seen in arterial blood samples; this suggests reflow and a prolonged residence time in the blood. These results show that particles the size of viruses are rapidly taken up into the lymphatics and blood vessels after subcutaneous deposition. (+info)
Laparoscopic aortofemoral bypass grafting: human cadaveric and initial clinical experiences.
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PURPOSE: Postoperative complications are mainly related to the surgical trauma derived from the extensive abdominal incision and dissection after a conventional aortofemoral bypass grafting procedure. In an attempt to reduce postoperative complications, a concept of video-endoscopic vascular surgery on the infrarenal aortoiliac artery has been developed. On the basis of our experience with the practicability of video-endoscopic vascular surgery in the pelvic region in an animal study and in a pilot study of human cadavers, the purpose of this report was to describe three different methods that we evaluated on human cadavers and that we partly applied to patients. METHODS: In this experimental study, three different approaches were used to perform video-endoscopic aortofemoral bypass grafting. We performed an observational trial on human corpses (n = 24) with the transabdominal-retroperitoneal approach (TARA), the extraperitoneal approach (EPA), and the transabdominal left paracolic approach (TAPA). The EPA also was applied to patients with aortoiliac occlusive diseases. RESULTS: The TARA on cadavers (n = 4) soon was abandoned because it caused a burdensome sliding of the intestine into the operative field adjacent to the renal vessels, particularly in cases with obese subjects. In comparison, the TAPA (n = 6) with right-sided positioning of the patient retained the intestine in the right upper abdomen throughout the procedure. Until a surgeon actually is acquainted with the anatomic landmarks and the laparoscopic preparation technique, the EPA (n = 14) is a challenging procedure that necessitates thorough training. As with the TAPA, the EPA represents a procedure that reveals constant exposure of the operating field, even in cases with obese subjects. In the clinical observational study (n = 7), aortobifemoral bypass grafting was achieved totally laparoscopically with the EPA. The mean operating time was 6.5 hours and ranged from 3 to 10 hours. Blood transfusions were necessary after surgery in three patients (range, 1 to 3 red packed blood cells). One patient, who had had occlusion of the inferior mesenteric artery, died of ischemic colitis at postoperative day 10. The other patients had uneventful postoperative courses with minor wound discomfort. CONCLUSION: Laparoscopic vascular surgery seems to be a promising procedure to minimize postoperative complications. On the basis of our experience, we do not favor the TARA. Because it necessitates steep Trendelenburg positioning to displace intra-abdominal organs, the TARA is not an appropriate approach, particularly in obese and cardiopulmonary frail cases. Contrarily, the TAPA and the EPA deliver potentially better results in terms of exposing the operative field and thus reducing operating time and perioperative morbidity rates. A prospective cadaveric and clinical trial may be justified to further evaluate the use of these surgical techniques. (+info)
Video-assisted crossover iliofemoral obturator bypass grafting: a minimally invasive approach to extra-anatomic lower limb revascularization.
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Graft infection continues to be one of the most feared complications in vascular surgery. It can lead to disruption of anastomoses with life-threatening bleeding, thrombosis of the bypass graft, and systemic septic manifestations. One method to ensure adequate limb perfusion after removal of an infected aortofemoral graft is extra-anatomical bypass grafting. We used a minimally invasive, video-assisted approach to implant a crossover iliofemoral obturator bypass graft in a patient with infection of the left limb of an aortofemoral bifurcated graft. This appears to be the first case report describing the use of this technique. (+info)
Posterior approach to the deep femoral artery.
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Unusual surgical approaches to the deep femoral artery are valuable when the standard anterior approach is difficult because of scarring or infection. A posterior approach to the deep femoral artery in patients, in whom all other approaches were unsuitable, is described. (+info)
The role of alpha and beta platelet-derived growth factor receptor in the vascular response to injury in nonhuman primates.
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Restenosis remains a significant clinical problem associated with mechanical interventional procedures for arterial revascularization or repair, including coronary angioplasty and stenting. Studies with rodents have established that platelet-derived growth factor (PDGF), a potent chemotactic and mitogenic agent for vascular smooth muscle cells, is a key mediator of lesion formation after vascular injury. To further explore this hypothesis in a more clinically relevant model, neutralizing monoclonal antibodies (mAbs) were used to examine the effect of selective inhibition of alpha or beta PDGF receptor (PDGFR) on neointima formation in nonhuman primates. Carotid arteries were injured by surgical endarterectomy and femoral arteries by balloon catheter dilatation. Immunostaining revealed that both injuries induced cell proliferation and the upregulation of beta PDGFR but not alpha PDGFR. By 7 days after injury, beta PDGFR staining was limited to the luminal region of the media, the small areas of neointima, and the adventitia. Nearly all bromodeoxyuridine-positive cells were found in these regions as well. After 30 days, a concentric neointima that stained strongly for beta PDGFR had formed in the carotid and femoral arteries. Treatment of baboons with anti-beta PDGFR mAb 2A1E2 for 6 days after injury reduced the carotid artery and femoral artery lesion sizes by 37% (P<0.05) and 48% (P<0.005), respectively, when measured at 30 days. Under the same conditions, treatment with anti-alpha PDGFR mAb 2H7C5 had no effect. These findings suggest that PDGF mediates neointima formation through the beta PDGFR, and that antagonism of this pathway may be a promising therapeutic strategy for reducing clinical restenosis. (+info)
Betamethasone-mediated vascular dysfunction and changes in hematological profile in the ovine fetus.
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Glucocorticoid administration to fetal sheep induces a sustained systemic blood pressure rise and an associated increase in femoral vascular resistance. We utilized a small vessel myograph to compare isometric vascular responses of small femoral arterial branches from fetal sheep infused intravenously with either betamethasone or vehicle in vivo from 128 days gestation. Changes in hematological parameters were also determined. Betamethasone was infused for 48 h to produce fetal plasma betamethasone concentrations similar to those observed in human fetuses after maternal treatment with betamethasone to accelerate fetal lung maturation. When compared with vessels removed from vehicle-infused fetuses, vessels obtained from betamethasone-treated fetuses exhibited 1) enhanced sensitivity to depolarizing potassium solutions; 2) no differences in response to the thromboxane mimetic U-46619 or norepinephrine; and 3) differential responses to vasodilators, enhanced sensitivity to ACh, but decreased response to bradykinin and forskolin. In addition, erythrocyte and leukocyte counts were increased in betamethasone-infused fetuses. These observations indicate that multiple mechanisms operate to increase fetal vascular resistance during antenatal betamethasone exposure. (+info)
A reexamination of the angiotoxicity of superselective injection of DMSO in the swine rete embolization model.
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BACKGROUND AND PURPOSE: There are a variety of embolization applications for non-adhesive, liquid agents. We reevaluated the potential microvascular angiotoxicity of superselective infusions of dimethyl sulfoxide (DMSO) using very long infusion rates in a previously described animal model. METHODS: Twenty-six swine underwent percutaneous femoral puncture for superselective catheterization of the artery of the rete while being continuously monitored for ECG and intraarterial pressure. Two volumes (0.5 or 0.8 mL) and three durations (30, 60, and 90 seconds) of superselective infusion of DMSO were used to evaluate the effect of a single-dose rate within an ipsilateral rete. Contralateral control infusions of normal saline were also administered. Acute hemodynamic and angiographic outcomes were assessed. After recovery, follow-up angiography and sacrifice were performed at either 10 or 28 days. Brains and retia were harvested for gross and microscopic histopathologic evaluation. RESULTS: No significant hemodynamic alterations occurred acutely. Twenty-three of the 24 infused retia showed variable acute vasospasm that typically was mild to moderate in severity and transient (10 to 20 minutes). Follow-up angiography at sacrifice always showed normal retial arterial anatomy. No adverse clinical sequelae were noted. Gross inspection of brains showed no evidence of infarction or subarachnoid hemorrhage. Microscopic histopathologic examination of retia showed mostly nonspecific changes in both exposed and control samples. Possible causal histotoxicity was seen in four retia (three of four exposed to higher dose rates), in which involvement was limited to one to three retial arteries. CONCLUSION: Lower total dose and dose rates of superselective infusion of DMSO into the retial microarterial network resulted in substantially less angiotoxicity than that found in a previous study, as defined by clinical, angiographic, gross, and histopathologic criteria. (+info)
A case of cervical pregnancy resistant to intramuscular methotrexate therapy is presented, which was successfully treated by intra-arterial methotrexate followed by selective prophylactic hypogastric artery embolization to avoid aggravating the vaginal bleeding. It is suggested that, in cervical pregnancies in which fertility preservation is desired, a stepwise conservative approach should be applied before resorting to surgical intervention. (+info)