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Biomedical subjects

J C Stanley

Publications and source records attributed to J C Stanley.

At least 19 recordsLinked to original sources
PubMed2003

Renal artery aneurysms: diagnosis, management and outcomes.

Renal artery aneurysms are an uncommon vascular entity and are more likely to affect younger patients without significant atherosclerotic risk factors as compared to patients with renal artery occlusive disease. Hypertension is a commonly associated disease and the renal artery aneurysm may be causal, exclusive of renal artery occlusive disease. Diagnosis is often made incidentally but arteriography is essential for good operative planning. The main complication of RAA is rupture, which is increased in peripartum females. Operative therapy is primarily in situ aneurysmectomy and angioplastic closure or exclusion and bypass, usually with autologous conduit. It is currently recommended that in good operative risk patients, repair is recommended for RAA >1.0 cm when hypertension present and RAA >1.5 to 2.0 cm when no hypertension present. Given the anatomic complexity of these lesions, little role for endovascular therapy is forecast.

Algorithms↗
PubMed2001

Interobserver variability in the evaluation of chronic mesenteric ischemia with gadolinium-enhanced MR angiography.

RATIONALE AND OBJECTIVES: The purpose of this study was to assess interobserver variability in the interpretation of gadolinium-enhanced magnetic resonance (MR) angiograms of splanchnic vessels in patients suspected of having chronic mesenteric ischemia (CMI). MATERIALS AND METHODS: Two readers blinded to the initial interpretation retrospectively reviewed gadolinium-enhanced MR angiograms obtained for suspected CMI in 26 patients (20 women and six men; age range, 23-77 years; mean age, 61 years) who also underwent conventional angiography. Each reader graded the degree of stenosis based on the percentage diameter reduction of the celiac artery (CA), superior mesenteric artery (SMA), and inferior mesenteric artery (IMA) by using a five-point ordinal scale: 0, no stenosis: 1, mild stenosis (<50%); 2, moderate stenosis (50%-75%); 3, severe stenosis (>75%); 4, occluded artery. Using the conventional angiogram as a reference standard, authors determined sensitivity and specificity for each observer, assigning two thresholds (grades 2 and 3) as significant stenoses. A kappa statistic (kappa) measured interobserver agreement. RESULTS: With grade 2 stenosis used as a threshold, cumulative accuracies for detecting significant stenosis were 0.95 (95% confidence interval, 0.86-0.99) for reader A and 0.97 (0.88-1.0) for reader B. Interobserver agreement for grading proximal splanchnic stenosis was 0.90 for CA, 0.92 for SMA, and 0.48 for IMA. CONCLUSION: Gadolinium-enhanced MR angiography is reproducibly accurate for detection of proximal splanchnic artery stenosis, with good to excellent interobserver agreement.

Adult↗
PubMed2001

Impact of chronic obstructive pulmonary disease on elective and emergency abdominal aortic aneurysm repair.

OBJECTIVE: Chronic obstructive pulmonary disease (COPD) is associated with abdominal aortic aneurysm (AAA) expansion and is considered by some to be a relative contraindication to conventional aortic surgery. This study was undertaken to determine if COPD increases operative death, morbidity, intensive care unit (ICU) length of stay (LOS), and hospital LOS, after AAA repair. METHODS: Data from national administrative records supplemented with laboratory data previously obtained for a system-wide study were analyzed in a retrospective review of 1053 consecutive patients (264 with and 789 without COPD) undergoing operation for intact or ruptured AAAs in Veterans Administration Hospitals from 1997 to 1998. Bivariate comparisons and multivariate regression were used to evaluate the impact of COPD on the number of days of ventilation, ICU LOS, total hospital LOS, and death, while controlling for other known risk factors, including acute myocardial infarction, renal failure, and age. RESULTS: The mortality rate in elective aneurysm patients did not differ (P =.99) between patients with (3.7%) or without COPD (3.7%). However, elective AAA repair was associated with longer hospital LOS (14.4 vs 12.3 days, P =.01), longer ICU LOS (6.5 vs 5.4 days, P =.01), and a higher incidence of requiring 96 hours or more ventilation (6.9% vs 3.6%, P =.02) in patients with COPD. Ruptured AAA affected 4.9% of patients and was strongly associated with COPD (P =.02); however, COPD did not result in a statistically significant increase in death (P =.25). CONCLUSIONS: Although COPD does not appear to increase operative death, it is associated with an increased risk of rupture. Elective repair of AAA should not be deferred in patients with COPD despite their higher LOSs and need for postoperative ventilation.

Aged↗
PubMed2001

Nitric oxide inhibition increases matrix metalloproteinase-9 expression by rat aortic smooth muscle cells in vitro.

OBJECTIVE: The hypothesis to be tested was that diminished bioavailable nitric oxide (NO) affects matrix metalloproteinase (MMP) expression and activation in vascular smooth muscle cells (SMCs). METHODS: Cultivated rat aortic SMCs (RA-SMCs) were exposed to increasing concentrations of L-N-monomethyl arginine (L-NMMA), a nonselective inhibitor of NO synthase, in the presence of proinflammatory cytokines (50 ng/mL interleukin [IL]-1beta, 50 ng/mL interferon-gamma, and 30 microg/mL lipopolysaccharide). Nitrite and nitrate, two of the final end products of NO metabolism, were measured in media collected at 48 hours with the use of the Saville assay (n = 4). MMP activity was measured with 1% gelatin zymography (n = 4). In separate experiments in which 2 ng/mL of IL-1beta and L-NMMA was used, MMP protein and messenger RNA (mRNA) levels were determined with Western blot analysis (n = 3) and semiquantitative reverse transcriptase-polymerase chain reaction (n = 3), respectively. Data were analyzed with nonparametric analysis of variance. RESULTS: Increasing concentrations of the NO synthase inhibitor L-NMMA caused a dose-dependent decrease (P <.05) in nitrite and nitrate production by RA-SMCs after cytokine exposure. Zymography documented an early dosedependent increase (P <.05 compared with cytokines alone) in 92-kd MMP activity, with no significant changes in 72-kd MMP activity after treatment with L-NMMA (P >.05 compared with cytokines alone). Reverse transcriptase-polymerase chain reaction and Western blot analysis revealed that the addition of L-NMMA to IL-1beta-stimulated RA-SMCs led to significant increases in MMP-9 mRNA (n = 3, P <.01 for 1.0 mmol/L L-NMMA) and MMP-9 protein levels (n = 3, P <.05), respectively. No differences in MMP-2 mRNA or protein levels were demonstrated. CONCLUSIONS: Inhibition of cytokine-induced NO expression in RA-SMCs is associated with a selective, dose-dependent increase in MMP-9 expression and synthesis. These findings suggest that alterations in local NO synthesis may influence MMP-9-dependent vessel wall damage.

Animals↗
PubMed2001

Efficacy and durability of autogenous saphenous vein conduits for lower extremity arterial reconstructions in preadolescent children.

OBJECTIVE: Limb length discrepancies (LLDs) in growing children may accompany extremity arterial occlusions. Revascularization with vein grafts has been questioned because of degenerative graft changes observed at other sites. This study was undertaken to define vein graft durability and efficacy in lower extremity revascularizations in preadolescent children. STUDY DESIGN: Fourteen children (10 boys, 4 girls) with a mean age of 7.3 years (range, 2-11 years) who underwent 16 lower extremity revascularizations with greater saphenous vein grafts were subjected to follow-up with graft ultrasonography, ankle/brachial indices (ABIs) with and without exercise, and limb length determinations. A mean of 5.7 years elapsed between the onset of ischemia and operation. Arterial occlusions resulted from cardiac catheterizations (11), arteritis (1), dialysis cannulation (1), and penetrating trauma (1). Indications for operation included LLD (6), claudication (4), both LLD and claudication (3), markedly diminished ABIs with a potential for LLD (2), and a traumatic transection with hemorrhage (1). The reconstructions with 15 reversed and one in situ vein grafts included iliofemoral (11), femorofemoral (1), aortofemoral (1), femoropopliteal (1), popliteal-popliteal (1), and popliteal-posterior tibial (1) arterial bypass grafts. RESULTS: Among patent grafts available for follow-up, 36% (5 of 14) remained unchanged, 50% (7 of 14) developed nonaneurysmal dilatation, and 14% (2 of 14) exhibited nonprogressive aneurysmal expansion. One graft became occluded, and one graft was lost to follow-up. Collectively, the grafts manifest an 11.2% expansion at an average of 10.7 years postoperatively. ABIs increased from 0.75 preoperatively to 0.97, at an average of 11.0 years postoperatively. LLDs were reduced from 1.66 to 1.24 cm, at an average of 11.4 years postoperatively. CONCLUSION: Vein graft reconstructions of lower extremity arteries in preadolescent children are durable. They provide an efficacious means of restoring normal blood flow, and in 70% of children their preexisting LLDs were reduced.

Angiography, Digital Subtraction↗
PubMed2001

Computed tomographic venography is specific but not sensitive for diagnosis of acute lower-extremity deep venous thrombosis in patients with suspected pulmonary embolus.

PURPOSE: Duplex ultrasound scanning (US) is the accepted standard means of diagnosis for lower-extremity suprageniculate deep venous thrombosis (LE-DVT). Computed tomographic venography (CTV) has been proposed as an alternative modality for diagnosis of LE-DVT in patients with suspected pulmonary embolism (PE). This study compared CTV with US as a means of diagnosing acute LE-DVT. METHODS: A retrospective review of US and CTV scans from 136 patients with suspected PE who underwent both studies to exclude acute LE-DVT at a single institution was performed. Studies were reviewed and coded in a blinded manner. US was considered to be the reference test. Direct costs of each study were determined by using commercial software. RESULTS: The sensitivity and specificity rates of CTV were 71% and 93%, respectively. The positive predictive value, negative predictive value, and accuracy rates of CTV were 53%, 97%, and 90%, respectively. DVT localization was the same in eight of 10 cases in which the results of both US and CTV were positive. CTV costs and charges per study were greater than those of US by $46.88 and $602.00, respectively. CONCLUSION: CTV is specific, but has a lower sensitivity rate and positive predictive value for the diagnosis of acute LE-DVT compared with US. Additionally, CTV is more costly than US scanning. Because of the lower sensitivity rate and positive predictive value and the increased cost of CTV, US remains the screening study of choice in cases of suspected acute LE-DVT.

Costs and Cost Analysis↗
PubMed2001

Renal artery aneurysms: a 35-year clinical experience with 252 aneurysms in 168 patients.

OBJECTIVE: To define the relevance of treating renal artery aneurysms (RAAs) surgically. SUMMARY BACKGROUND DATA: Most prior definitions of the clinical, pathologic, and management features of RAAs have evolved from anecdotal reports. Controversy surrounding this clinical entity continues. METHODS: A retrospective review was undertaken of 168 patients (107 women, 61 men) with 252 RAAs encountered over 35 years at the University of Michigan Hospital. Aneurysms were solitary in 115 patients and multiple in 53 patients. Bilateral RAAs occurred in 32 patients. Associated diseases included hypertension (73%), renal artery fibrodysplasia (34%), systemic atherosclerosis (25%), and extrarenal aneurysms (6.5%). Most RAAs were saccular (79%) and noncalcified (63%). The main renal artery bifurcation was the most common site of aneurysms (60%). RAAs were often asymptomatic (55%), with a diagnosis made most often during arteriographic study for suspected renovascular hypertension (42%). RESULTS: Surgery was performed in 121 patients (average RAA size 1.5 cm), including 14 patients undergoing unilateral repair with contralateral RAA observation. The remaining 47 patients (average RAA size 1.3 cm) were not treated surgically. Operations included aneurysmectomy and angioplastic renal artery closure or segmental renal artery reimplantation, aneurysmectomy and renal artery bypass, and planned nephrectomy for unreconstructable renal arteries or advanced parenchymal disease. Eight patients underwent unplanned nephrectomy, being considered a technical failure of surgical therapy. Dialysis-dependent renal failure occurred in one patient. There were no perioperative deaths. Late follow-up (average 91 months) was available in 145 patients (86%). All but two arterial reconstructions remained clinically patent. Secondary renal artery procedures included percutaneous angioplasty, branch embolization, graft thrombectomy, and repeat bypass for late aneurysmal change of a vein conduit. Among 40 patients with clearly documented preoperative and postoperative blood pressure measurements, 60% had a significant decline in blood pressure after surgery while taking fewer antihypertensive medications. Late RAA rupture did not occur in the nonoperative patients, but no lessening of this group's hypertension was noted. CONCLUSION: Surgical therapy of RAAs in properly selected patients provides excellent long-term clinical outcomes and is often associated with decreased blood pressure.

Adolescent↗
PubMed2001

ANG II type 1 receptor downregulation does not require receptor endocytosis or G protein coupling.

ANG II type 1 (AT(1)) receptors respond to sustained exposure to ANG II by undergoing downregulation of absolute receptor numbers. It has been assumed previously that downregulation involves endocytosis. The present study hypothesized that AT(1) receptor downregulation occurs independently of receptor endocytosis or G protein coupling. Mutant AT(1) receptors with carboxy-terminal deletions internalized <5% of radioligand compared with 65% for wild-type AT(1) receptors. The truncated AT(1) receptors retained the ability to undergo downregulation. These data suggest the existence of an alternative pathway to AT(1) receptor degradation that does not require endocytosis, per se. Point mutations in either the second transmembrane region or second intracellular loop impaired G protein (G(q)) coupling. These receptors exhibited a biphasic pattern of downregulation. The earliest phase of downregulation (0-2 h) was independent of coupling to G(q), but no additional downregulation was observed after 2 h of ANG II exposure in the receptors with impaired coupling to G(q). These data suggest that coupling to G(q) is required for the later phase (2-24 h) of AT(1) receptor downregulation.

Amino Acid Substitution↗
PubMed2000

Sea buckthorn berry oil inhibits platelet aggregation.

A small-scale preliminary cross-over study was conducted to investigate the effects of supercritical CO(2)-extracted sea buckthorn berry oil (SBO) on some risk factors of cardiovascular disease. Special features of the oil are high proportions of palmitic (16:0), oleic (18:1n-9), palmitoleic (16:1n-7), linoleic (18:2n-6), and alpha-linolenic (18:3n-3) acids as well as vitamin E, carotenoids, and sterols. Twelve healthy normolipidemic men were recruited and each volunteer consumed SBO and fractionated coconut oil (control) 5 g per day for a period of 4 weeks in a random order (wash-out 4-8 weeks). Phospholipid fatty acids, plasma lipids, and glucose were unaffected by SBO supplementation. Instead, a clear decrease in the rate of adenosine-5'-diphosphate-induced platelet aggregation and maximum aggregation were found. This suggested the beneficial effects of SBO on blood clotting, but further studies on the dose-response effects are needed to assess the practical use of SBO supplements.

Journal Article↗
PubMed2000

Incidence of femoral and popliteal artery aneurysms in patients with abdominal aortic aneurysms.

OBJECTIVE: The purpose of this study was to determine the incidence of femoral and popliteal aneurysms in men and women who have abdominal aortic aneurysms (AAAs) and to assess potential etiologic differences in patients with and without these lower extremity aneurysms. METHODS: We studied 313 consecutive patients with AAAs encountered from 1995 to 1998 who underwent prospective ultrasound scanning to detect the presence or absence of femoral and popliteal aneurysms. Patients with and without these extremity aneurysms were compared for differences in potential etiologic risk factors with each other and with a statewide population of patients with AAAs. RESULTS: A total of 51 femoral and popliteal aneurysms were encountered, all occurring in male patients. Among the 251 men with AAAs, the incidence of femoral or popliteal aneurysms was 14%, compared with 0% among the 62 women with AAAs (P <.01). A family history of aneurysmal disease was present in only one (3%) of the 36 men with these extremity arterial aneurysms, a significant finding (P <.01) when compared with the family history that was positive for aneurysmal disease in 14 women (23%). Peripheral arterial occlusive disease affected 14 (39%) of the 36 men with peripheral arterial aneurysms versus 20 (9%) of the 215 men without these aneurysms (P <.01). Most other etiologic variables studied proved not to be different among the various groups of patients examined. CONCLUSION: The incidence of femoral and popliteal aneurysms in persons with AAAs appears higher than that noted previously. Femoral and popliteal aneurysmal disease preferentially affects men; however, the basis for this sex difference is unknown. Few common etiologic factors differed between men with and without these extremity aneurysms. Most femoral and popliteal artery aneurysms in this study were undetectable on physical examination, suggesting that ultrasound scanning is appropriate in the recognition of peripheral aneurysms among men with AAAs.

Aged↗
PubMed2000

Evaluation of a cerebral oximeter as a monitor of cerebral ischemia during carotid endarterectomy.

BACKGROUND: Stroke is an important contributor to perioperative morbidity and mortality associated with carotid endarterectomy (CEA). This investigation was designed to compare the performance of the INVOS-3100 cerebral oximeter to neurologic function, as a means of detecting cerebral ischemia induced by carotid cross-clamping, in patients undergoing carotid endarterectomy with cervical plexus block. METHODS: Ninety-nine patients undergoing 100 CEAs with regional anesthesia (deep or superficial cervical plexus block) were studied. Bilateral regional cerebrovascular oxygen saturation (rSO2) was monitored using the INVOS-3100 cerebral oximeter. Patients were retrospectively assigned to one of two groups: those in whom a change in mental status or contralateral motor deficit was noted after internal carotid clamping (neurologic symptoms; n = 10) and those who did not show any neurologic change (no neurologic symptoms; n = 90). Data from 94 operations (neurologic symptoms = 10 and no neurologic symptoms = 84) were adequate for statistical analyses for group comparisons. A relative decrease in ipsilateral rSO2 after carotid occlusion (calculated as a percentage of preocclusion value) during all operations (n = 100) was also calculated to determine the critical level of rSO2 decrease associated with a change in neurologic function. RESULTS: The mean (+/- SD) decrease in rSO2 after carotid occlusion in the neurologic symptoms group (from 63.2 +/- 8.4% to 51.0 +/- 11.6%) was significantly greater (P = 0.0002) than in the no neurologic symptoms group (from 65.8 +/- 8.5% to 61.0 +/- 9.3%). Logistic regression analysis used to determine if a change in rSO2, calculated as a percentage of preclamp value, could be used to predict change in neurologic function was highly significant (likelihood ratio chi-square = 13.7; P = 0.0002). A 20% decrease in rSO2 reading from the preclamp baseline, as a predictor of neurologic compromise, resulted in a sensitivity of 80% and specificity of 82.2%. The false-positive rate using this cutoff point was 66.7%, and the false-negative rate was 2.6%, providing a positive predictive value of 33.3% and a negative predictive value of 97.4%. CONCLUSION: Monitoring rSO2 with INVOS-3100 to detect cerebral ischemia during CEA has a high negative predictive value, but the positive predictive value is low.

Adult↗
PubMed1999

Effects of somatostatin, somatostatin analogs, and endothelial cell somatostatin gene transfer on smooth muscle cell proliferation in vitro.

OBJECTIVE: Somatostatin analogs inhibit neointimal hyperplasia and smooth muscle cell (SMC) proliferation in vivo. The gene transfer of somatostatin to endothelial cells (ECs) represents a potential means of local delivery of somatostatin to areas of arterial injury. This study tested the hypothesis that the retroviral gene transfer of somatostatin to ECs would inhibit SMC proliferation in vitro and evaluated the effects of somatostatin analogs on DNA synthesis and the growth of SMCs. METHODS: Media transfer and coculture were used to determine the effects of somatostatin-producing ECs on SMC proliferation in vitro. The effects of a variety of somatostatin isoforms and analogs on the proliferation of SMCs, mitogenesis of serum-restimulated quiescent SMCs, and arterial explants were measured. RESULTS: Despite the production of biologically relevant concentrations of somatostatin by ECs, no inhibition of SMC proliferation was noted. Somatostatin analogs inhibited DNA synthesis in arterial explants but did not inhibit either DNA synthesis or growth of cultured SMCs, which showed a likely effect of somatostatin on the initial transition in SMC phenotype. CONCLUSION: Somatostatin exerts inhibitory effects on SMC proliferation only during the early transition to a proliferative phenotype. There are significant differences between this in vivo transition and the standard serum-restimulated model of cultured SMCs. These differences may account for the failure of somatostatin to inhibit SMC proliferation in the standard in vitro models.

Animals↗
PubMed1999

Lymphoepithelioma-like carcinoma of the renal pelvis.

We report the first documented case of undifferentiated carcinoma of the renal pelvis with a prominent lymphoid stroma (lymphoepithelioma-like carcinoma [LELC]). LELCs are morphologically identical to nasopharyngeal carcinoma and are rarely seen in the urinary tract, with only isolated cases involving the urinary bladder and ureter. The tumor was composed entirely of large pale staining malignant epithelial cells with ill-defined borders arranged in syncytial sheets separated by mainly reactive lymphocytes, occasional plasma cells and histiocytes. Tumor cells were immunoreactive to cytokeratin and were negative for leukocyte common antigen. Awareness of LELC is important, as it should be distinguished from lymphoma or inflammatory lesions including, xanthogranulomatous pyelonephritis.

Aged↗
PubMed1999

An assessment of contributions made by extracranial tissues during cerebral oximetry.

This study was designed to determine the extent of contribution made by extracranial tissues to estimation of regional cerebrovascular saturation (ScO2) during cerebral oximetry. Thirty four patients undergoing carotid endarterectomy under regional anesthesia were studied. Bilateral ScO2 monitoring with two INVOS 3100 A cerebral oximeters was used. Effect of occlusion of external carotid artery (ECA) for five minutes on ScO2 readings followed by occlusion of internal and common carotid arteries was studied. ScO2 readings at 1 minute intervals were stored on computer disks for off-line analysis. Numerical data were subjected to a two way repeated measures analysis of variance to study the effect of side (ipsilateral or contralateral) and phase (pre clamp, ECA clamp, ICA clamp and post clamp) of operation. A value of p<0.05 was considered significant. There was no significant change in ScO2 on the contralateral side. On the ipsilateral hemisphere ScO2 decreased from 67.4+/-8.5 to 65.6+/-8.3 with ECA occlusion and to 61.4+/-9.6 after ICA occlusion returning to 64.8+/-9.8 after all clamps were released. Decrease after ECA occlusion was not significant (p = 0.12) while that after ICA occlusion was significant when compared to pre clamp value (p<0.001). After release of all clamps ipsilateral ScO2 returned toward baseline but remained significantly lower (p<0.05) than pre clamp values. When readings from two hemispheres were compared, a significant difference (p<0.001) was noted during ICA occlusion only. We conclude that the mathematical algorithm used for calculation of ScO2 by INVOS 3100 A cerebral oximeter measures predominantly the intracranial cerebrovascular saturation.

Aged↗