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Biomedical subjects

S C Coley

Publications and source records attributed to S C Coley.

35 records · Page 2Linked to original sources
PubMed1998

Pulmonary arteriovenous malformations.

Pulmonary arteriovenous malformations (PAVMs) are uncommon lesions, but are the cause of considerable morbidity and occasional mortality. They most commonly occur in association with hereditary haemorrhagic telangectasia and screening of families with this condition is therefore important. Embolization of PAVMs by coils is a well tolerated effective procedure with a low complication rate in skilled hands. Treatment results in both symptomatic and physiological improvement, and evidence for a reduction in stroke and cerebral abscess is accumulating. Radiological techniques now represent the primary treatment of choice, with surgical resection rarely required.

Arteriovenous Malformations↗
PubMed1998

Giant aneurysm of the petrous internal carotid artery: diagnosis and treatment.

We report the case of a giant fusiform aneurysm of the petrous internal carotid artery in a 15-year-old patient who had presented with headache, hearing loss and Horner's syndrome. Definitive radiological diagnosis was made by non-invasive imaging techniques, including magnetic resonance angiography (MRA). The aneurysm was obliterated by endovascular balloon occlusion following successful tolerance of test occlusion of the internal carotid artery.

Adolescent↗
PubMed1998

Delayed massive epistaxis due to traumatic intracavernous carotid artery pseudoaneurysm.

Recurrent epistaxes after head injury may rarely be due to a traumatic intracavernous carotid artery pseudoaneurysm. The head injury is usually associated with fracture of the skull base and the epistaxes are severe with the first episode generally occurring one to three months after the initial trauma. We present a case which illustrates the role of high resolution computed tomography (CT) scanning and also magnetic resonance angiography (MRA) in achieving the diagnosis.

Adult↗
PubMed1998

Endovascular occlusion with a new mechanical detachable coil.

OBJECTIVE: Metallic coils have been used for vascular embolization for many years but controlled-release coils have only recently become commercially available. Most of these devices are microcoils that were manufactured primarily for the packing of intracerebral aneurysms; therefore, they lack radial force and are not ideal agents for the occlusion of high-flow lesions such as pulmonary arteriovenous malformations (PAVMs). The objective of this study was to review our experience with a new detachable coil based on the conventional Gianturco-Wallace coil. SUBJECTS AND METHODS: The new detachable coil was initially used for the treatment of varicocele in 20 patients. Subsequently, the coil was used in 48 patients during 90 procedures for the treatment of PAVMs. RESULTS: A total of 548 coils were used. Complete occlusion of the testicular vein was achieved in all patients with varicocele. Successful occlusion of the PAVM being treated was achieved in all patients, and no instances of recanalization were documented in any of the patients who returned for follow-up angiography. Forty-one coils had to be removed completely from the catheter before detachment because of inappropriate size or position. Eight coils failed to detach easily, and six of these had to be removed. Most of these device failures were associated with kinking of the screw thread mechanism between the coil and the delivery wire. CONCLUSION: The Jackson detachable coil allows safer, more accurate, and more distal embolization of PAVMs than is possible with nondetachable coils. Complications associated with its use have been few.

Adult↗
PubMed1997

The performance of three portable infusion-pump devices set to deliver 2 mL/hr.

The performance of three portable infusion-pump devices set to deliver 2 mL/hr was studied. Portable infusion-pump devices (CADD-1, Paragon, and Singleday Infusor) were set to deliver 5% or 25% dextrose in water at 2 mL/hr for 24 hours at two environmental temperatures (25 and 35 degrees C). There were a total of 12 types of experimental runs, and each run was performed in triplicate. Flow rate accuracy and flow continuity were measured by a computerized gravimetric technique; effusate weights were measured and recorded at 30-second intervals for two hours at the beginning and two hours at the end of each run. Mean flow rates among the three devices did not differ significantly. Mean flow rate was significantly higher for the 5% dextrose solution than for the 25% dextrose solution, for the 35 degree C temperature than for the 25 degree C temperature, and during the first two hours of delivery than during the last two hours. The CADD-1 units showed an interruption of flow lasting about 30 seconds and recurring every 60 seconds; the other devices had fairly constant flow. Mean flow continuity differed significantly among the three devices. Mean flow continuity was significantly higher for the 5% dextrose solution and for the 25 degree C temperature. Flow continuity differed among three representative portable infusion-pump devices set to deliver 2 mL/hr, but flow rate accuracy did not. Fluid viscosity, environmental temperature, and elapsed time affected flow rate accuracy and flow continuity.

Analysis of Variance↗
PubMed1997

Spiral CT and the pre-operative assessment of pancreatic adenocarcinoma.

AIM: To determine the value of spiral computed tomography (CT) in the pre-operative assessment of pancreatic carcinoma. PATIENTS AND METHODS: Fifty patients with proven pancreatic carcinoma referred for pancreatoduodenectomy underwent pre-operative spiral CT using a dedicated pancreatic protocol to determine tumour resectability. Twenty-eight patients subsequently underwent surgical exploration. RESULTS: Pre-operative imaging suggested that 15 tumours were resectable, and macroscopic clearance was complete in 13 giving a positive predictive value (PPV) of 87%. PPV of irresectability was 92%. CT underestimated locally advanced disease (n = 2), missed small hepatic metastases (n = 1), and lymphadenopathy (n = 1). CT overestimated SMV encasement in 1 case, otherwise prediction of vascular patency and compromise was correct. The conspicuity of small resectable carcinomas was improved by spiral scanning. CONCLUSION: The optimised pancreatic parenchymal enhancement and vascular opacification achieved by spiral CT improves tumour detection of small carcinomas, allows accurate assessment of peripancreatic vessels, and reliably predicts both resectable and irresectable disease. CT remains inherently limited in the prediction of early extrapancreatic non-vascular spread and of lymphatic metastases.

Adenocarcinoma↗
PubMed1985

Equine alternative pathway activation by unsensitized rabbit red blood cells.

The equine alternative complement pathway has been partially characterized and compared to the equine classical activation pathway. A dose-dependent lysis of RbRBC was observed with peak lytic values noted within 10 minutes at 37 degrees C when rabbit red blood cells (RbRBC) were used as an alternative pathway activator. Sheep red blood cells (SRBC) sensitized with rabbit hemolysin or partially purified equine IgM antibodies were equally sensitive to lysis. Dilution of the commercial hemolysin by 1/5 reduced lysis from 90% to 38% in the presence of constant cell numbers. Hemolysis of SRBC peaked at 10 minutes and the majority of lysis occurred within 10 minutes. Dilution of equine sera by as little as 1/5 decreased hemolytic activity for SRBC to 21.5% from greater than 90% with undiluted sera. The alternative pathway protein, equine factor B, was tested using RbRBC and monitored by its differential susceptibility to heat treatment at 50 degrees C. This treatment led to almost complete inactivation after a 15-minute incubation. An apparent heat-dependent decay of certain classical pathway components was also observed after 50 degrees C treatment. This sensitivity was indicated by a reduction in the lytic activity for sensitized SRBC. Treatment for 15 minutes at 56 degrees C with either RbRBC or SRBC was sufficient to abolish hemolytic activity in all equine sera tested. Chelation of cations with 0.04 M EDTA blocked expression of alternative and classical pathway activation; however, chelation of Ca++ ions with 10 mM EGTA containing 1 mM Mg++ ions permitted lysis of the RbRBC but not the SRBC. A dose-related Mg++-ion dependence for RbRBC hemolytic activity was observed as the concentration of Mg++ was increased to 1.0 mM. In addition, our results obtained with pre-colostral foal serum strongly suggest that natural antibody to RbRBC was of little importance in the lysis observed with these cells. These results also show that the equine alternative pathway activation may require Ca++ ions. If Ca++ ions are required, the equine alternative pathway is quite different from any other mammalian complement system so far described. Our results suggest that the alternative pathway of activation is of major importance in the equine complement system. Confirmation of this hypothesis requires both purification of the components involved as well as further characterization.

Animals↗
PubMed1985

Onchocerca cervicalis in horses: dermal histopathology.

A histopathological study of ventral midline skin from midwestern U.S. horses with and without onchocerciasis due to Onchocerca cervicalis found perivascular mononuclear dermatitis as the most consistent difference between the two groups. Seasonal variation in parasite numbers or cellular influxes was not observed. Eosinophilic dermatitis was observed in horses with onchocerciasis and dermatitides of unknown etiology.

Animals↗
PubMed1984

Lipid and protein composition of the surface tegument from larvae of Taenia taeniaeformis.

A tegumental fraction from fully developed larvae of Taenia taeniaeformis was recovered by low speed centrifugation following incubation of the parasites in a 0.1% solution of digitonin. Scanning electron microscopy of the parasite carcass revealed no surface microtrichs, and transmission electron microscopy indicated that the subtegumental layer was undamaged. The tegumental fraction, judging from the distribution of 3H-Concanavalin A, was enriched for surface components, exhibited low succinic dehydrogenase activity, and an electron microscopic examination of the pellet showed a slightly expanded but intact distal tegumental layer. The fraction, which made up 3.0% of the dry weight of the parasite, consisted of 52% protein and 32% lipid. Thirty-three proteins, ranging in Mr from 9,000 to 276,000 daltons, were detected after sodium dodecyl sulfate solubilization and polyacrylamide gel electrophoresis. Seven of these proteins were glycoproteins. Cholesterol, phosphatidylethanolamine, phosphatidylserine, and glycosphingolipids were the major lipids.

Animals↗
PubMed1983

Chemical composition of lipid droplets isolated from larvae of Taenia taeniaeformis.

Young developing larvae of Taenia taeniaeformis contain large deposits of osmiophilic droplets. These droplets are spherical, approximately 1.5 micron in diameter and are primarily localized in the tegument. After cellular disruption of the parasite, followed by centrifugation, the lipid droplets were found in a floating layer of lipid. The lipid droplets in the lipid layer resembled the droplets as seen in situ. The isolated lipid droplets mainly consisted of neutral lipids with triglycerides, sterol esters, sterols and free fatty acids being the major components. Smaller amounts of other neutral lipids were also present, as were glycolipids, phospholipids and protein. The lipid droplets were not membrane bound. The relationship between lipid droplets, lipid utilization and membrane synthesis during parasite growth is discussed.

Animals↗
PubMed1982

Equine onchocerciasis: lesions in the nuchal ligament of midwestern U.S. horses.

Nuchal ligaments from midwestern U.S. horses infected with adult Onchocerca sp. were studied. The prevalence of Onchocerca sp. infection in horses increased with age. Ten percent of horses less than one year old were infected, 28% of horses one to five years old, 48% of horses six to 15 years old, and 90% of horses over 16 years old. Lesions in Onchocerca sp.-infected nuchal ligaments varied with age of the horse. Horses less than five years old had few or no lesions, whereas most horses six to 15 years old had focal mineralization and granuloma formation around adult worms. In infected nuchal ligaments of horses over 16 years old, mineralization was much greater and fewer normal parasites were found. Our data suggest that infection by viable parasites is terminated naturally.

Age Factors↗
PubMed1982

Equine ocular onchocerciasis: histopathologic study.

Equine eyes (368) were examined clinically and histologically for abnormalities associated with the presence of ocular microfilariae of naturally occurring Onchocerca sp infection. Forty of the eyes had microfilariae in the conjunctiva, but distinguishing clinical abnormalities were not associated with their presence. In 1 horse with ocular microfilariae that was treated with diethylcarbamazine daily for 2 weeks, ocular tissue samples were obtained before, during, and after the horse was treated, and the samples were compared histologically. During treatment of the horse, microfilariae apparently moved from the conjunctival stroma into the perilimbal corneal stroma; inflammatory cells were more abundant in the perilimbal tissues. The tissue samples obtained before and after the treatment appeared similar.

Age Factors↗