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Biomedical subjects

J McElroy

Publications and source records attributed to J McElroy.

12 recordsLinked to original sources
PubMed1999

Malignant peripheral nerve sheath tumour of the spinal accessory nerve.

A 50-year-old man presented with a left-sided neck mass. Clinical examination revealed a large fluctuant 7 cm x 7 cm mass in the left posterior triangle. Magnetic resonance imaging (MRI) revealed an encapsulated soft tissue lesion. He underwent exploration of the neck and a 14 cm by 8 cm mass enfolding the accessory nerve was identified and completely excised. Histological examination of the surgical specimen showed features in keeping with a malignant peripheral nerve sheath tumour (MPNST). We present the clinical and pathological features of this condition.

Accessory Nerve Diseases↗
PubMed1999

Effects of retrograde femoral intramedullary nailing on the patellofemoral articulation.

OBJECTIVE: To determine the patellofemoral contact areas as well as mean and maximal pressures after retrograde intramedullary nailing in a cadaveric model. STUDY DESIGN: Pressure-sensitive film was used to analyze patellofemoral joint pressures after insertion of a retrograde femoral nail in a cadaveric specimen. METHODS: A retrograde femoral nail was inserted into seven cadaveric knees. Pressure-sensitive film was placed into the patellofemoral joint and physiologic loads (700 newtons) were applied to the knee joint at 90 degrees and 120 degrees of flexion. Testing was performed with the nail three millimeters deep to the cartilage (In), flush with the cartilage (Flush), and one millimeter prominent (Out). The intact knee served as the Control. RESULTS: The mean contact areas showed no statistical differences among the four groups. There was a significant increase in mean pressure at 120 degrees and maximum pressure at 90 degrees and 120 degrees for the Out group when compared with the Control, In, and Flush groups (p < 0.001). CONCLUSIONS: There were no significant differences in mean contact pressure, contact area, or maximum pressure among the Control, three-millimeter insertion depth, or flush insertion groups. There was, however, a significant increase in mean and maximum pressures with the nail one millimeter prominent. These results indicate that placement of a retrograde femoral intramedullary nail is critical, but that proper placement should not significantly influence the biomechanics of the patellofemoral joint.

Biomechanical Phenomena↗
PubMed1996

Giant polypoid basal cell carcinoma.

Basal cell carcinomas may attain giant proportions due primarily to recurrence and neglect. Giant basal cell carcinomas (5 cm or more in diameter) are of four clinical subtypes: noduloulcerative, morpheaform, superficial, and polypoid. We report a patient with a typical polypoid lesion of fifteen years' duration on his shoulder. The polypoid variant differs from other giant basal cell carcinomas in several important ways: the polypoid lesions appear on the torso or extremity, rather than the head or neck, as beefy-red, friable, exophytic masses for which the patient typically has had no previous treatment; the histologic type tends to be nonaggressive; and finally, the lesions are amenable to surgical cure with low metastatic potential.

Adult↗
PubMed1993

Reconstruction of the severely atrophic maxilla with autogenous iliac bone graft and hydroxylapatite/decalcified freeze-dried bone allograft in the same patient: a preliminary report.

Procedures to augment the severely atrophic maxilla using sinus lift techniques have been increasingly used for endosseous implant placement. A case report is presented in which a patient had a severely resorbed maxilla bilaterally. A situation developed during the course of treatment which created a unique opportunity to compare an autogenous iliac graft on one side with a hydroxylapatite/freeze-dried bone allograft on the other.

Alveolar Bone Loss↗
PubMed1992

Progressive albuminuria and glomerulosclerosis in a rat model of chronic renal allograft rejection.

A significant proportion of renal allografts fail within several months or years after transplantation, primarily because of chronic rejection. The etiology and pathophysiology of this condition remain unclear. We studied the renal function, morphology, and immunohistology, in parallel, among F344-to-Lewis allografts (n = 23) and isografts (n = 13) over the course of 24 weeks. Only an initial 10-day course of CsA (5 mg/kg/day) was given to both groups to prevent acute rejection. Hypertension did not develop, although awake systolic blood pressure was significantly higher in allografts at the end of the study. Significant differences in urine albumin excretion (UalbV) between isografts and allografts were evident as early as 4 weeks after engraftment but rose dramatically by 20 weeks (3.3 +/- 0.7 vs. 21.2 +/- 3.7 mg/day, respectively, P < .001). This pattern continued until the conclusion of the study (5.0 +/- 1.1 vs. 53.5 +/- 7.6 mg/day, P < .001). Serum creatinine values were only significantly elevated in allografts at 16 weeks, which temporally corresponded to the dramatic increase in UalbV. However, renal blood flow and glomerular filtration rate, measured by paraaminohippurate and inulin clearances, respectively, were significantly lower in allografted organs, at 24 weeks. The frequency of glomerulosclerosis lesions was significantly increased in allografted kidneys at 24 weeks and correlated with UalbV values. Glomerular localization of mononuclear leukocyte subsets were equivalent between allografts and isografts; however, the numbers of interstitial macrophages, CD8+, and pan-T-cells were all significantly greater in allografts at 24 weeks. The infiltration of significantly greater numbers of macrophages and lymphocytes into the tubulointerstitium of the allograft group suggests a mononuclear leukocyte effector cell mediation of the progressive glomerular abnormalities in this model of chronic renal allograft rejection in the rat.

Albuminuria↗
PubMed1989

The effect of glutathione content on renal function following warm ischemia.

Reperfusion after ischemia produces tissue injury due to free radicals generated during the reflow period. Glutathione (GSH) mediates against this oxidant damage by scavenging free radicals and protecting cells against injury. In an attempt to reduce the injury caused by free radicals, rat kidneys were pretreated with GSH monoethyl ester to elevate renal GSH fivefold. Previous studies in a renal artery occlusion model showed that pretreated kidneys in comparison to untreated controls were functionally impaired as measured by glomerular filtration rate, urine flow rate, and histology. To eliminate systemic effects of the pretreatment, kidneys were subjected to a fixed period of warm ischemia but flushed of blood and transplanted into nonpretreated syngeneic recipients. As before, pretreated kidneys exhibited marked functional impairment. We conclude that (i) elevation of renal GSH with GSH monoethyl ester enhances rather than prevents renal dysfunction and (ii) the enhancement of renal ischemic injury following pretreatment is not due to nonspecific systemic effects of GSH monoethyl ester pretreatment.

Animals↗
PubMed1986

A prospective analysis of the accuracy and cost-effectiveness of digital subtraction angiography for living-related renal donor evaluation.

From 1982 to 1984, we conducted a prospective study to evaluate the usefulness of i.v. renal digital subtraction angiography (DSA) for living-related donor (LRD) evaluation. Twenty-eight LRDs were evaluated with the traditional approach of intravenous pyelography (IVP) and standard catheter arteriography (SCA) (group 1). During the same period, 33 LRDs underwent renal DSA and IVP from a single i.v. contrast injection (group 2). If renal arterial imaging with DSA was considered satisfactory, no further radiographic studies were done (group 2-A, n = 23). If renal arterial imaging with DSA was not satisfactory, SCA was then obtained (group 2-B, n = 10). DSA alone accurately defined the number and location of renal arteries in 21 of 23 patients from group 2-A, and in 5 of 10 patients from group 2-B. The major limitation of DSA was in patients with multiple renal arteries; accurate imaging was obtained in only 7 of these 13 patients (54%). In group 2 overall, preoperative renal imaging was not accurate in 2 of 33 patients (6%); in both cases, an unsuspected polar artery was found at nephrectomy. The mean cost per patient of all radiographic renal imaging studies was $953.00 for group 2 and $1721.00 for group 1. These data suggest that the approach of preferentially evaluating LRDs with DSA-IVP, and obtaining SCA only if DSA yields poor visualization, is more cost-effective but not as accurate as the traditional policy of obtaining SCA and IVP in all cases.

Angiography↗
PubMed1985

Renal revascularization by end-to-end anastomosis of the hepatic and renal arteries.

From June 1981 to January 1984, 13 patients with atherosclerotic renal artery disease underwent revascularization by end-to-end anastomosis of the hepatic and renal arteries. Renal revascularization was indicated to preserve renal function and/or to treat associated hypertension. An aortorenal bypass was not possible owing to severe aortic atherosclerosis or a prior aortic operation. Right renal revascularization was performed by end-to-end anastomosis of the renal artery to the common hepatic artery in 7 patients, right hepatic artery in 4, left hepatic artery in 1 or gastroduodenal artery in 1. Postoperatively, 2 patients suffered a necrotic gallbladder owing to ischemia and 1 of these patients died. Liver enzymes were elevated immediately postoperatively in 11 patients but returned to normal within 2 weeks in each case. Currently, all 12 surviving patients have normal liver function, well controlled blood pressure and improved renal function. End-to-end anastomosis of the hepatic and renal arteries is an effective method of revascularization but specific measures must be taken to avoid complications of gallbladder ischemia.

Aged↗
PubMed1983

Effect of high doses of naloxone on shuttle avoidance acquisition in rats.

Administration of high doses of naloxone intraperitoneally (2.5-10.0 mg/kg) resulted in a dose-related impairment of avoidance response acquisition in a shuttle avoidance paradigm in rats. Naloxone in this dose range produced a significant decrease in the number of intertrial responses but did not result in a significant dose-response. Escape latencies were not affected by naloxone administration at any dose tested. The effect of naloxone on activity and nociception are implicated as possible causes of the observed behavior. The results are discussed as behavioral evidence supporting theories postulating multiple opiate receptors.

Animals↗