Biomedical subjects

J D Flaherty

Publications and source records attributed to J D Flaherty.

5 recordsLinked to original sources

PubMed1998

Saccular aneurysm induction by elastase digestion of the arterial wall: a new animal model.

OBJECTIVE: To develop a rabbit aneurysm model that is more realistic in gross appearance and histological features than previous models and to enable the development of a larger animal model. METHODS: Ten rabbits received porcine pancreatic elastase, five at the right common carotid artery bifurcation and five others at the right superior thyroid artery origin. One control animal received collagenase and another received papaverine, each at the right superior thyroid artery origin. The agents were topically delivered to the arterial adventitia with a microsyringe after surgical exposure of the targeted arteries. The arteries were monitored for aneurysm growth with a video camera for up to 3 hours and were then removed and processed for histology. RESULTS: Saccular aneurysms developed in one of five animals after elastase application at the carotid bifurcation and in all five animals receiving elastase at the superior thyroid artery origin. Among the six aneurysms, recurrent minor hemorrhages occurred in four, thrombosis of the aneurysm sac in three, and rupture causing severe bleeding in one. Histological sections revealed thin-walled aneurysms composed only of collagen fibers and some cellular elements. No saccular dilation resulted from papaverine application. Collagenase application resulted in a hemorrhagic-thrombotic lesion in the arterial wall but no aneurysm formation. CONCLUSION: Arterial saccular aneurysms were induced in rabbits by topical application of elastase with an easy and efficient method. These aneurysms are histologically similar to natural aneurysms, and their arterial nature renders them more authentic than those of surgical models. This aneurysm model may serve as a foundation for further aneurysm research.

Animals↗

PubMed1998

The empty toe phenomenon: a type of closed degloving.

A 46-year-old man sustained a crush injury, including several phalangeal fractures and vascular disruption, when his left foot was run over by a forklift truck. Although the skin was not broken, the middle and distal phalanges of his second toe were displaced, appearing absent on radiography. This was a closed degloving injury, a rare form of trauma involving tissue separation without skin disruption. Closed degloving injuries, which can occur in conjunction with bone displacement in the toes, can produce a striking radiographic appearance, referred to in this report as the "empty toe."

Amputation, Surgical↗

PubMed1997

Rapid saccular aneurysm induction by elastase application in vitro.

OBJECTIVE: To develop a new saccular aneurysm model in vitro using elastase to study aneurysm initiation, growth, and rupture and to create a new in vivo aneurysm model to test endovascular therapies. METHODS: Seventeen common carotid arteries excised from freshly killed pigs and sheep were treated with seven different methods of elastase delivery. The arteries were mounted in a saline-filled flow chamber. They received pulsatile flow for 48 hours, or until the resulting aneurysms ruptured. Changes were continuously monitored with video camera recordings and validated with histological sections. RESULTS: All eight arteries treated topically, either on the intimal or on the adventitial surface, with elastase concentrations greater than 1 U/mm2, developed saccular aneurysms; five of them ruptured within 48 hours. All four arteries treated with surface concentrations of 0.1 U/mm2 via microcatheter infusion into the lumen developed fusiform aneurysms. None of the arteries that received surface concentrations less than 0.1 U/mm2 developed aneurysms. Histological sections revealed a reduced number of cellular element in a stretched collagen matrix at the dome of the saccular aneurysms. CONCLUSION: After empirically testing several methods of elastase delivery, we were able to induce saccular, bifurcation-type aneurysms in animal arterial specimens. These aneurysms are histologically similar and more authentic than surgical models. The procedure is easy and reproducible. Our results suggest a possible enzymatic role in aneurysm formation and highlight the dramatic effects of selective arterial elastic damage. Also, the rapid growth of our experimental aneurysms may reflect the speed of the natural process.

Aneurysm, Ruptured↗

PubMedDate not supplied

Carbon dioxide column angioscopy: a new endovascular imaging technique.

A new angioscopic technique with a CO(2) gas medium for prolonged viewing sessions in the carotid artery is described. A stationary column of CO(2) gas, angled 17-30 degrees subhorizontally and buoyed against a balloon catheter, can be safely maintained. During 10-20-min sessions in dogs, endothelia, thrombi, stent filaments, coils, and an intimal flap were visualized. This technique eliminates the need for continuous saline infusion, which has prevented the application of angioscopy in the carotid artery.

Angioscopes↗

PubMedDate not supplied

Depiction of carotid plaque ulceration and other plaque-related disorders by intravascular sonography: a flow chamber study.

PURPOSE: To evaluate the ability of intravascular sonography to depict plaque ulceration and to identify the limitations of and the artifacts associated with this technique. METHODS: Twenty-eight human carotid arteries were mounted in a pulsatile flow chamber and examined with intravascular sonography. We compared 140 intravascular sonograms with gross pathologic and histologic sections. Ulcerations with a diameter or depth of at least 0.5 mm were sought. RESULTS: All eight arteries with ulcerated plaques and nine of 10 individual ulcerations were depicted by intravascular sonography. One artery (one of 140 arterial cross sections) with a small mural thrombus was misinterpreted as ulcerated. Our intravascular sonographic measurements underestimated the gross ulceration dimensions by 22% (depth) and 17% (orifice diameter). CONCLUSIONS: Intravascular sonography is highly accurate for the diagnosis of plaque ulceration. The central position of the high-frequency transducer within the target vessel facilitates high resolution of the arterial lumen-wall border, permitting more powerful definition of small ulcerations than available by other diagnostic methods. However, the utility of invasive intravascular sonography for detecting carotid ulcerations cannot be determined until the pathologic significance of plaque ulceration is clearly defined.

Aged↗