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Biomedical subjects

J Dion

Publications and source records attributed to J Dion.

At least 19 recordsLinked to original sources
PubMed1995

High-flow, small-hole arteriovenous fistulas: treatment with electrodetachable coils.

We present one case of carotid-cavernous fistula caused by percutaneous treatment of trigeminal neuralgia and one case of vertebrovertebral fistula caused by percutaneous internal jugular vein cannulation. Each fistula had a small arteriovenous communication that prevented the use of detachable balloons. Endovascular transarterial treatment of these two iatrogenic fistulas with electrically detachable platinum coils was performed. Both fistulas were occluded with preservation of the parent artery, and the patients have fully recovered.

Aged↗
PubMed1993

Microtubules are not an essential component of phytohemagglutinin-dependent signal transduction in Jurkat T lymphocytes.

We have used two disruptors of the cytoskeleton microtubular network (colchicine and vinblastine) to investigate the role of microtubules in Phaseolus vulgaris phytohemagglutinin (PHA) signal transduction in Jurkat T cells. Both drugs decreased but did not abolish the PHA-dependent Ca2+ response of Jurkat cells. Neither colchicine nor vinblastine had any major effects on the PHA-dependent turnover of the mono-, di-, tri-, and tetra-substituted phosphorylated derivatives of D-myo-inositol or the cellular distribution of protein kinase C (PKC) activity. However, both microtubule disruptors increased interleukin-2 (IL-2) production. Whereas vinblastine enhanced IL-2 production approximately twofold at all the concentrations tested (0.1, 1.0, and 10 microM), colchicine did so only at a 10 microM concentration. When a combination of PHA and 12-O-tetradecanoyl-13-O-acetyl phorbol (TPA) was used, a small increase in IL-2 production was observed only in the presence of vinblastine (10 microM). In contrast to recent reports that microfilaments may be involved in the regulation of signal transduction, our data suggest that this is not the case for microtubules in PHA-dependent signal transduction in Jurkat T cells.

Animals↗
PubMed1992

Endovascular treatment of posterior circulation aneurysms by electrothrombosis using electrically detachable coils.

In a multicenter study, 120 patients with intracranial aneurysms presenting a high surgical risk were treated using electrolytically detachable coils and electrothrombosis via an endovascular approach. The results of treatment in patients with posterior fossa aneurysms (42 patients with 43 aneurysms) are presented. The most frequent clinical presentation was subarachnoid hemorrhage (24 cases). The clinical follow-up periods ranged from 1 week to 18 months. Complete aneurysm occlusion was obtained in 13 of 16 aneurysms with a small neck and in four of 26 wide-necked aneurysms. A 70% to 98% thrombosis of the aneurysm was achieved in 22 of 26 aneurysms with a wide neck and in three of 16 small-necked aneurysms. One aneurysm could not be treated due to a technical complication. Two cases required postprocedural surgical clipping of a residual aneurysm. One patient (originally in Hunt and Hess Grade V) experienced procedural rupture of the aneurysm requiring an emergency parent artery occlusion. He eventually died 5 days later. Another patient (originally in Grade IV) had coil migration and posterior cerebral artery territory ischemia. A third patient developed a permanent neurological deficit (hemianopsia) after complete occlusion of a wide-necked basilar bifurcation aneurysm. One patient, harboring an inoperable giant basilar bifurcation aneurysm, died from aneurysm bleeding 18 months after partial occlusion. Overall morbidity and mortality rates related to treatment were 4.8% (two cases) and 2.4% (one case), respectively (2.6% and 0% if considering only patients in Hunt and Hess Grades I, II, and III). It is suggested that this technique is a viable alternative in the management of patients with posterior fossa aneurysms associated with high surgical risk. Longer angiographic and clinical follow-up study is necessary to determine the long-term efficacy of this recently developed endovascular occlusion technique. Close postoperative angiographic and clinical monitoring of patients with wide-necked subtotally occluded aneurysms is mandatory to check for potential aneurysmal recanalization, regrowth, and rupture.

Adolescent↗
PubMed1991

Electrothrombosis of saccular aneurysms via endovascular approach. Part 2: Preliminary clinical experience.

Fifteen patients with high-risk intracranial saccular aneurysms were treated using electrolytically detachable coils introduced via an endovascular approach. The patients ranged in age from 21 to 69 years. The most frequent clinical presentation was subarachnoid hemorrhage (eight cases). Considerable thrombosis of the aneurysm (70% to 100%) was achieved in all 15 patients, and preservation of the parent artery was obtained in 14. Although temporary neurological deterioration due to the technique was recorded in one patient, no permanent neurological deficit was observed in this series and there were no deaths. It is believed that this new technology is a viable alternative in the management of patients with high-risk intracranial saccular aneurysms. It may also play an important role in the occlusion of aneurysms in the acute phase of subarachnoid hemorrhage.

Adult↗
PubMed1990

Use of a new mixture for embolization of intracranial vascular malformations. Preliminary experimental experience.

The internal carotid artery system in swine has a special anatomic configuration similar to a brain "arterial-arterial malformation." The internal carotid artery breaks up into a multitude of fine channels (rete mirabile) situated at the base of the skull on the side of the hypophysis. This anatomic arterial model was used to analyze acute and chronic angiographic and histological changes after occlusion of the rete mirabile with I) avitene, II) avitene, and 50% ethanol, III) avitene, 30% ethanol and Polyvinyl alcohol, IV) avitene 50% ethanol and Polyvinyl alcohol, V) IBCA and VI) silk. Histopathological changes observed in the rete mirabile six weeks following occlusion demonstrated that a mixture of avitene, 30% ethanol and Polyvinyl alcohol and IBCA produced the best anatomic results. Embolization with avitene, PVA and ethanol induced a more bland histological reaction than the one observed with IBCA. Preliminary clinical experience with this mixture is reassuring in those cases in which the AVM was surgically resected. The partially thrombosed AVM was easily depressed and compressed by the neurosurgeon allowing for satisfactory hemostasis in and around the nidus of the AVM.

Animals↗
PubMed1990

Persistent primitive trigeminal artery-cavernous sinus fistulas: report of two cases.

Two cases of persistent primitive trigeminal artery-cavernous sinus fistulas are presented. In one case, the fistula was treated by using a two-balloon tandem technique. This method was accomplished by introducing, inflating, and detaching a silicone balloon into the trigeminal artery, thus preserving the carotid and basilar blood flow. An unusual case of a similar fistula with only contralateral exophthalmos is also reported. The relationship between this type of fistula and the presence of aneurysms on the persistent primitive trigeminal artery and the relationship with traumatic events are discussed.

Adult↗
PubMed1990

Intraoperative digital subtraction angiography and the surgical treatment of intracranial aneurysms and vascular malformations.

Intraoperative digital subtraction angiography using commercially available equipment was employed to confirm the precision of the surgical result in 105 procedures for intracranial aneurysms or arteriovenous malformations (AVM's). Transfemoral selective arterial catheterization was performed in most of these cases. A radiolucent operating table was used in all cases, and a radiolucent head-holder in most. In five of the 57 aneurysm procedures, clip repositioning was required after intraoperative angiography demonstrated an inadequate result. In five of the 48 AVM procedures, intraoperative angiography demonstrated residual AVM nidus which was then located and resected. In two cases intraoperative angiography failed to identify residual filling of an aneurysm which was seen later on postoperative angiography, and in one case the intraoperative study failed to demonstrate a tiny residual fragment of AVM which was seen on conventional postoperative angiography. Two complications resulted from intraoperative angiography: one patient developed aphasia from cerebral embolization and one patient developed leg ischemia from femoral artery thrombosis. This technique appears to be of particular value in the treatment of complex intracranial aneurysms and vascular malformations.

Angiography, Digital Subtraction↗
PubMed1989

Head and neck lesions: MR-guided aspiration biopsy.

Aspiration biopsy guided with computed tomography (CT) has long been a valuable tool in the evaluation of head and neck disease. The ability to obtain diagnoses without the need for surgery has had a significant effect on patient treatment. Magnetic resonance (MR) imaging is now rapidly replacing CT as the primary imaging study for many head and neck diseases. The standard stainless steel needles used for CT-guided biopsy are unsuitable for MR-guided biopsy because significant ferromagnetic artifacts obscure the underlying anatomy. A new needle has recently been designed specifically for use with MR imaging. This needle has far less magnetic susceptibility and therefore does not cause significant image distortion. The authors describe the use of this needle in MR-guided aspiration biopsy of a variety of lesions in the head and neck.

Adult↗
PubMed1989

Cranial arteriovenous malformations in neonates: color Doppler imaging with angiographic correlation.

Five neonates with cranial arteriovenous malformations were studied with color Doppler sonography. Excellent correlation was found between sonography and subsequent angiography. In three patients with vein of Galen aneurysms, sonography showed a cystic structure with rapid or swirling flow. Careful adjustment of the color Doppler system was required to demonstrate flow in another patient with a dural arteriovenous malformation. An arteriovenous fistula in a fifth patient appeared as an area of increased flow. Arterial feeders and major draining veins were visualized in all five patients. Color Doppler imaging also was used to assess the effect of embolic or operative therapy in three of the patients. We conclude that color Doppler sonography is able reliably to characterize flow patterns in neonatal cranial arteriovenous malformations. Color Doppler imaging also is helpful in assessing flow after embolic or surgical therapy.

Cerebral Angiography↗
PubMed1987

Treatment of claudication with pentoxifylline: are benefits related to improvement in viscosity?

Forty-five patients with short-distance claudication were treated with pentoxifylline. The initial claudication distance increased significantly (32.5 m, p = 0.02) and the absolute claudication distance (ACD) increased significantly (49.5 m, p = 0.001) while the patients were receiving pentoxifylline. Patients with initial elevated viscosity levels were more likely to have decreased viscosity with pentoxifylline than were patients with normal viscosity levels (p = 0.01). No significant improvement in ACD or viscosity was noted in 51% of patients. Both ACD and viscosity improved in 15% of patients, viscosity improved without improvement in ACD in 9%, and ACD improved without improvement in viscosity in 25%.

Blood Viscosity↗
PubMed1986

Clinical events following neuroangiography. A prospective study.

The authors prospectively evaluated the clinical event rate over a 72 hour period following femorocerebral angiography in 1002 procedures. The neurologic event rate was 1.3 per cent in the first 24 hours (0.1% permanent) and 1.8 per cent between 24 and 72 hours (0.3% permanent). The non-neurologic event rate (mostly hematomas) was 7.2 per cent. There were no deaths. One hundred and nine pieces of data per procedure were analysed statistically. Delayed cerebral ischemia does occur and could be secondary to the procedure. The low risk of judiciously performed cerebral angiography was confirmed. Carefully cataloguing all events for up to 72 hours neither verifies nor excludes angiography as the cause of deterioration.

Adult↗
PubMed1983

Traumatic subarachnoid-mediastinal fistula mimicking a ruptured aorta.

A 35-year-old man, injured in an automobile accident was found to have a subarachnoid-mediastinal fistula that mimicked a ruptured aorta. Of 16 reported cases of traumatic subarachnoid-mediastinal fistula, this is only the third in which the fistulous communication was with the extrapleural space only. The possibility of subarachnoid-mediastinal fistula, although rare, should be entertained in injuries to the thoracocervical spine when neurologic symptoms are present.

Accidents, Traffic↗
PubMed1977

Antinuclear antibody: predictive of lymphocyte response in rheumatoid arthritis.

The phytohemagglutinin induced response of lymphocytes was studied in two groups of rheumatoid patients differing only in the presence or absence of antinuclear antibodies (ANA). The response was found to be depressed in 16 ANA positive and normal in 14 ANA negative patients. Antinuclear antibody screening may serve as a simple method to identify a subgroup of immunodepressed rheumatoid patients who may be potential candidates for immunostimulation therapy.

Antibodies, Antinuclear↗