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L N Hopkins

Publications and source records attributed to L N Hopkins.

At least 19 recordsLinked to original sources
PubMed2001

Ineffective secondary prevention in survivors of cardiovascular events in the US population: report from the Third National Health and Nutrition Examination Survey.

BACKGROUND: Survivors of myocardial infarction (MI) or stroke are at high risk for subsequent cardiovascular events. There is limited assessment of the effectiveness of risk factor modification through current secondary preventive strategies in the US population. We determined the adequacy of risk factor modification in 1252 survivors of MI, stroke, or both in a nationally representative sample of US adults and identified factors related to inadequate control of risk factors. METHODS: The adequacy of control for hypertension, diabetes mellitus, cigarette smoking, alcohol use, and hypercholesterolemia was assessed by personal interview, blood pressure measurements, and serum glycosylated hemoglobin and cholesterol levels in 17 752 US adults who participated in the Third National Health and Nutrition Examination Survey between 1988 and 1994. We also evaluated the role of potentially related factors, including age, sex, race/ethnicity, educational attainment, socioeconomic status, and medical insurance status using multivariate logistic regression analysis. RESULTS: Of 738 known hypertensive persons, hypertension was uncontrolled in 388 (53%). Previously undiagnosed hypertension was detected in 138 others (11%). Of 289 diabetic persons, serum glucose control was inadequate in 141. Of 1252 survivors, 225 (18%) were currently smoking, and heavy alcohol use was observed in 56 persons. Hypercholesterolemia was poorly controlled in 185 (46%) of 405 persons with known hypercholesterolemia. Undetected hypercholesterolemia was observed in 160 persons (13%). In the multivariate analysis, high-risk profiles were more likely to be observed in persons aged 46 to 65 years, women, and African Americans. CONCLUSIONS: High prevalence of inadequate secondary prevention was found in a subset of the US population at highest risk for stroke and MI. Considerable efforts are required to effectively implement risk factor modification strategies after MI or stroke, particularly in middle-aged persons, African Americans, and women.

Aged↗
PubMed2001

Cocaine use and the likelihood of nonfatal myocardial infarction and stroke: data from the Third National Health and Nutrition Examination Survey.

BACKGROUND: Numerous case series have implicated cocaine use as a cause of both myocardial infarction (MI) and stroke on the basis of the temporal relationship between drug use and event onset. Increasing cocaine use in the US population, especially in younger individuals, mandates a more extensive investigation of this relationship. METHODS AND RESULTS: We determined the association of cocaine use with self-reported physician diagnosis of MI or stroke in a nationally representative sample of 10 085 US adults aged 18 to 45 years who participated in the Third National Health and Nutrition Examination Survey. A total of 46 nonfatal MIs and 33 nonfatal strokes were reported. After adjusting for differences in age, sex, race/ethnicity, education, hypertension, diabetes mellitus, cholesterol level, body mass index, and cigarette smoking, persons who reported frequent lifetime cocaine use had a significantly higher likelihood of nonfatal MI than nonusers (odds ratio, 6.9; 95% confidence interval, 1.3 to 58) but not stroke. In this age group, the population-attributable risk percent of frequent cocaine for nonfatal MI was estimated as 25%. CONCLUSION: Regular cocaine use was associated with an increased likelihood of MI in younger patients. Approximately 1 of every 4 nonfatal MIs in persons aged 18 to 45 years was attributable to frequent cocaine use in this survey. Behavior modification by public awareness and education may reduce the cardiovascular morbidity associated with cocaine use.

Adolescent↗
PubMed2001

Superselective intra-arterial carboplatin for treatment of intracranial neoplasms: experience in 100 procedures.

BACKGROUND: The results of animal studies suggest that superselective intra-arterial infusion allows the permeation of a high concentration of chemotherapeutic agents within intracranial neoplasms. In the present report, we review our clinical experience with the 100 intra-arterial infusions of carboplatin in intracranial neoplasms not responsive to other treatment modalities. METHODS: Carboplatin was infused in 100 separate sessions (24 patients) as a mean dose of 286+/-60 mg/m2 (range 34-377 mg/m2). RMP-7, a bradykinin analog, was used as an adjunct in 28 sessions (6 patients). The infusions were performed through superselective microcatheterization of the following arteries: internal carotid (n = 39), middle cerebral (n = 61), posterior cerebral (n = 21) and anterior cerebral (n = 10). The frequency of neurological and non-neurological complications, and survival were recorded. In a subset of 10 patients, tumor volume was measured by serial magnetic resonance images to assess therapeutic response to therapy. RESULTS: The mean age of the patients was 44.5 years (range 26-67 years); 13 were men. The tumors were classified as glioblastoma multiforme (n = 12), metastatic tumor (n = 1), high-grade astrocytoma (n = 6), and anaplastic mixed glioma (n = 5). Follow-up was available for 23 patients (mean 22 months, range 2-69 months). Survival beyond 1 year after initiation of intra-arterial carboplatin therapy was documented in 12 of the 23 patients. A total of 13 neurological complications including seizures (n = 7), transient neurological deficits (n = 5), and ischemic stroke (n = 1) were observed in 100 procedures. A lower frequency of complications occurred in men and in patients who received adjunctive RMP-7. Volumetric analysis of serial magnetic resonance images demonstrated tumor mass reduction in 3 out of 10 patients. An increase in tumor mass ranging from 23% to 230% was observed in the other 7 patients over a period ranging from 2.3 to 37.7 months since initiation of carboplatin therapy. CONCLUSIONS: Superselective intra-arterial administration of carboplatin appears feasible and was associated with predominantly transient neurological complications. The addition of RMP-7 to carboplatin therapy appears to be at least as safe as the administration of carboplatin alone and requires further investigation as a means of chemotherapeutic dose intensification.

Adenocarcinoma↗
PubMed2001

Current status of carotid bifurcation angioplasty and stenting based on a consensus of opinion leaders.

OBJECTIVE: Carotid bifurcation angioplasty and stenting (CBAS) has generated controversy and widely divergent opinions about its current therapeutic role. To resolve differences and establish a unified view of CBAS' present role, a consensus conference of 17 experts, world opinion leaders from five countries, was held on November 21, 1999. METHODS: These 17 participants had previously answered 18 key questions on current CBAS issues. At the conference these 18 questions and participants' answers were discussed and in some cases modified to determine points of agreement (consensus), near consensus, (prevailing opinion), or divided opinion (disagreement). RESULTS: Conference discussion added two modified questions, placing a total of 20 key questions before the participants, representing four specialties (interventional radiology, seven; vascular surgery, six; interventional cardiology, three; neurosurgery, one). It is interesting that consensus was reached on the answers to 11 (55%) of 20 of the questions, and near consensus was reached on answers to 6 (30%) of 20 of the questions. Only with the answers to three (15%) of the questions was there persisting controversy. Moreover, both these differences and areas of agreement crossed specialty lines. Consensus Conclusions: CBAS should not currently undergo widespread practice, which should await results of randomized trials. CBAS is currently appropriate treatment for patients at high risk in experienced centers. CBAS is not generally appropriate for patients at low risk. Neurorescue skills should be available if CBAS is performed. When cerebral protection devices are available, they should be used for CBAS. Adequate stents and technology for performing CBAS currently exist. There were divergent opinions regarding the proportions of patients presently acceptable for CBAS treatment (<5% to 100%, mean 44%) and best treated by CBAS (<3% to 100%, mean 34%). These and other consensus conclusions will help physicians in all specialties deal with CBAS in a rational way rather than by being guided by unsubstantiated claims.

Angioplasty↗
PubMed2001

Quantitative analysis of injured, necrotic, and apoptotic cells in a new experimental model of intracerebral hemorrhage.

OBJECTIVE: To develop a new survival model of intracerebral hemorrhage (ICH) in rabbits and study the patterns of cellular injury in different regions 24 hrs after introduction of hematoma. Quantitation and characterization of injured cells in regions adjacent and distant to the hematoma have not been performed. DESIGN: Prospective case-control study. SUBJECTS: Ten New Zealand rabbits. INTERVENTION: We introduced ICH in six anesthetized New Zealand rabbits by autologous blood injection under arterial pressure in the deep white matter in the frontal lobe. MEASUREMENTS AND MAIN RESULTS: Hematoxylin and eosin staining was performed in six animals with ICH after 24 hrs to quantify intact, injured, and necrotic cells in regions proximal and distant to the hematoma, and the results were compared with four control animals. Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining was performed to quantify apoptotic cells in specified regions in five animals with ICH, and the results were compared with four control animals. All cell counts were performed by one investigator who used 100x oil emersion microscopy. The presence of localized hematoma was confirmed in all six animals with blood infusion. Compared with controls, animals with ICH had a significantly higher proportion of swollen cells in both the inner (55.9% +/- 3.0% vs. 26.8% +/- 1.7%; p < .05) and the outer (59.8% +/- 4.6% vs. 27.7% +/- 4.5%; p < .05) rim of the perihematoma region. A small proportion of shrunken dark cells were observed in both the inner (4.0% +/- 1.5%) and the outer (3.6% +/- 1.0%) rim of the perihematoma region. The remaining cells were considered morphologically intact. A large proportion of cells trapped within the matrix of the hematoma were either shrunken dark cells (48.8% +/- 16.4%) or swollen (38.8% +/- 15.1%). In the TUNEL-stained sections, a high burden of apoptotic cells was observed in the matrix of the hematoma (17.5 +/- 6.3 cells per high power field) but not in the perihematoma regions (less than two cells per high power field). CONCLUSIONS: A reproducible model of ICH in rabbits is described. At 24 hrs, the perihematoma region contains relatively large proportions of morphologically intact or reversibly injured (swollen) cells, suggesting the possibility of an extended window for therapeutic intervention.

Analysis of Variance↗
PubMed2001

Treating complex nervous system vascular disorders through a "needle stick": origins, evolution, and future of neuroendovascular therapy.

In the past few decades, dramatic improvements have occurred in the field of neuroendovascular surgery. Endovascular therapy today is a well-established treatment modality for a variety of cerebrovascular and nonvascular central nervous system diseases. The foundation of this spectacular evolution was laid by the efforts of pioneering visionaries who often worked alone and under difficult, almost impossible, conditions. Ongoing device development and refinement have revolutionized the field at a dizzying, exhilarating pace. With a better understanding of the molecular basis of diseases and further advancements in gene therapy, neuroendovascular techniques have an enormous potential for application to the entire spectrum of central nervous system diseases as a minimally invasive vehicle for the delivery of biological factors.

Angioscopy↗
PubMed2001

Open-label phase I clinical study to assess the safety of intravenous eptifibatide in patients undergoing internal carotid artery angioplasty and stent placement.

OBJECTIVE: Eptifibatide, a competitive platelet glycoprotein IIb-IIIa receptor inhibitor with high selectivity and a short half-life, has been demonstrated to reduce the risk of ischemic events associated with coronary interventions. However, its role in neurointerventional procedures needs to be analyzed. We report the results of an open-label Phase I study to evaluate the safety of the use of eptifibatide during carotid angioplasty and stent placement. METHODS: Each study patient received eptifibatide administered intravenously as a 135-microg/kg single-dose bolus, then a 0.5-microg/kg/min infusion for 20 to 24 hours during carotid angioplasty and stent placement. The primary efficacy end point was the 30-day composite occurrence of death, cerebral infarction, transient ischemic attack, and unplanned or urgent surgical intervention, thrombolysis, or subsequent percutaneous revascularization. The primary safety end point was bleeding. Bleeding complications were classified as major (hemoglobin decrease >5 g/dl), minor (hemoglobin decrease 3-5 g/dl), or insignificant. RESULTS: Ten patients (mean age, 73 yr; four men) were treated by use of the study protocol. One patient developed a minor stroke postprocedurally (National Institutes of Health Stroke Scale score of 21 at 24 h that improved to 1 at 7 d). Three patients underwent scheduled coronary artery bypass graft surgery 4 to 12 days after undergoing carotid angioplasty and stent placement. At 1-month follow-up, no new ischemic events were observed. Major or minor bleeding was not observed in any patient. Insignificant bleeding was observed in two patients. CONCLUSION: The use of eptifibatide as an adjunct to carotid angioplasty and stent placement seems to be safe. Further studies are required to analyze the effectiveness and role of eptifibatide in neurointerventional procedures.

Aged↗
PubMed2001

Angioplasty of intracranial occlusion resistant to thrombolysis in acute ischemic stroke.

OBJECTIVE: Thrombolysis has been demonstrated to improve revascularization and outcome in patients with acute ischemic stroke. Many centers now apply thrombolytic therapy locally via intra-arterial infusion. One therapeutic benefit is the ability to cross soft clots with a guidewire and to perform mechanical thrombolysis. In some instances, reopened arteries reocclude as a result of either thrombosis or vasospasm. We report the use of balloon angioplasty during thrombolysis for acute stroke. METHODS: From June 1995 through June 1999, 49 patients underwent intra-arterial therapy for acute stroke. In this group, nine patients (seven men and two women) were treated with balloon angioplasty after inadequate recanalization with thrombolytic infusion. The mean age of these patients was 67.9 years. Nine matched control patients who underwent thrombolysis alone without angioplasty were chosen for comparison. RESULTS: In the group of nine patients who had angioplasty, the mean National Institutes of Health Stroke Scale score at presentation was 21.8 +/- 5.4. Four patients had residual distal occlusion after angioplasty, and one patient had a hemorrhagic conversion. Of the five patients in which recanalization was successful, none had reocclusion of the balloon-dilated vessel. The mean score at 30 days for the five survivors was 12.6 +/- 14.9, for an improvement of 7.0 +/- 14.2. Among the nine control patients, the mean score at presentation was 20.3 +/- 5.2; the mean score at 30 days for the five survivors was 19.4 +/- 7.7, for an improvement of 4.2 +/- 7.8. CONCLUSION: In our experience, balloon angioplasty is a safe, effective adjuvant therapy in patients who are resistant to intra-arterial thrombolysis. The use of balloon angioplasty may prevent reocclusion in a stenotic artery and permit distal infusion of thrombolytic agents.

Aged↗
PubMed2001

Intra-arterial third-generation recombinant tissue plasminogen activator (reteplase) for acute ischemic stroke.

OBJECTIVE: We prospectively evaluated the safety and recanalization efficacy of intra-arterially administered reteplase, a third-generation recombinant tissue plasminogen activator, for treating ischemic stroke in patients considered poor candidates for intravenously administered alteplase therapy. METHODS: Patients were considered poor candidates for intravenously administered therapy because of severity of neurological deficits, interval from onset of symptoms to presentation of 3 hours or more, or recent major surgery. We administered a maximum total dose of 8 U of reteplase intra-arterially in 1-U increments via superselective catheterization. Adjunctive angioplasty of the occluded artery was performed in seven patients. Angiographic evidence of perfusion and thrombus was graded by use of modified Thrombolysis in Myocardial Infarction (TIMI) criteria. Neurological examinations were performed before and 24 hours and 7 to 10 days after treatment. RESULTS: Sixteen consecutive patients were treated (mean age, 64.1 +/- 16.4 yr; seven were men). Initial National Institutes of Health Stroke Scale scores ranged from 10 to 26. Time from onset of symptoms to treatment ranged from 2 to 9 hours. Occlusion sites were the cervical internal carotid artery (n = 4), intracranial internal carotid artery (n = 4), middle cerebral artery (n = 6), and vertebrobasilar artery (n = 2). Complete or near-complete perfusion (TIMI Grade 3 or 4) was achieved in the arteries in 14 patients (88%), with partial recanalization (TIMI Grade 2) or minimal response (TIMI Grade 1) in the arteries in one patient each. Neurological improvement (defined as decrease of four or more points in National Institutes of Health Stroke Scale score) was observed in 7 (44%) of the 16 patients at 24 hours. Symptomatic intracerebral hemorrhage occurred in one patient; three other patients experienced intracerebral hemorrhages that did not result in neurological worsening. The overall mortality during hospitalization was 56%, related to massive ischemic stroke (n = 7), withdrawal of care at the family's request after the development of aspiration pneumonia and renal failure (n = 1), and a combination of intracerebral hemorrhage and massive ischemic stroke (n = 1). CONCLUSION: In this study, intra-arterially administered reteplase in doses up to 8 U with or without angioplasty resulted in a high rate of recanalization. This strategy should be considered in treating patients considered poor candidates for intravenous thrombolysis.

Acute Disease↗
PubMed2001

Who should be screened for asymptomatic carotid artery stenosis? Experience from the Western New York Stroke Screening Program.

OBJECTIVE: Identification of significant asymptomatic carotid artery stenosis (ACAS) is important because of the stroke-risk reduction observed with carotid endarterectomy. The authors developed and validated a simple scoring system based on routinely available information to identify persons at high risk for ACAS using data collected during a community health screening program at various sites in western New York. A total of 1331 unselected volunteers without previous stroke, transient ischemic attack, or carotid artery surgery were evaluated by personal interview and duplex ultrasound. The main outcome measure was carotid artery stenosis > 60% by duplex ultrasound. In the derivation set (n = 887), 4 variables were significantly associated with ACAS > 60%: age > 65 years (odds ratio [OR] = 4.1, 95% confidence interval [CI] = 2.6-6.7), current smoking (OR = 2.0, 95% CI = 1.2-3.5), coronary artery disease (OR = 2.4, 95% CI = 1.5-3.9), and hypercholesterolemia (OR = 1.9, 95% CI = 1.2-2.9). Three risk groups (low, intermediate, and high) were defined on the basis of total risk score assigned on the basis of the strength of association. The scheme effectively stratified the validation set (n = 444); the likelihood ratio and posttest probability for ACAS in the high-risk group were 3.0 and 35%, respectively, and in the intermediate and low-risk groups were 1.4 and 20% and 0.4 and 7%, respectively. Routinely available information can be used to identify persons in the community at high risk for ACAS. Doppler ultrasound screening in this subgroup may prove to be cost-effective and have an effect on stroke-free survival.

Aged↗
PubMed2001

Determination of blood flow velocity and transit time in cerebral arteriovenous malformation using microdroplet angiography.

Advancement in imaging and biomedical technology has improved the use of catheter-based transarterial embolization (occlusive therapy) of cerebral arteriovenous malformations (AVMs). Among a variety of embolic agents, liquid adhesives (acrylates) have proven to be more successful in permanent obliteration of AVMs. The use of liquid adhesives requires the experience and skill of the operator. However, acquiring accurate information on blood flow and transit times through the AVM prior to embolization can optimize the treatment. In addition, knowledge of the polymerization time and behavior of the acrylate enables a complete and safe occlusion of the arteriovenous transition within the AVM nidus. Standard commercially available iodine-based contrast agents seem to be insufficient to determine AVM transit times from angiograms. For a more accurate assessment of AVM transit times, the use of a nonsoluble contrast agent (Ethiodol) and a high-speed digital subtraction angiography (DSA) is suggested. Small amounts (<20 microl) of Ethiodol were infused to create microdroplets and traced using DSA at 15 fps. Transit time, defined as the time interval required for a droplet to reach the venous part of the AVM after being flushed from the tip of the catheter, could be accurately calculated. Postprocessing was used to calculate trajectories and velocities of microdroplets.

Angiography, Digital Subtraction↗
PubMed2001

Fatal progression of posttraumatic dural arteriovenous fistulas refractory to multimodal therapy. Case report.

The authors report the case of a man who suffered from progressive, disseminated posttraumatic dural arteriovenous fistulas (DAVFs) resulting in death, despite aggressive endovascular, surgical, and radiosurgical treatment. This 31-year-old man was struck on the head while playing basketball. Two weeks later a soft, pulsatile mass developed at his vertex, and the man began to experience pulsatile tinnitus and progressive headaches. Magnetic resonance imaging and subsequent angiography revealed multiple AVFs in the scalp, calvaria, and dura, with drainage into the superior sagittal sinus. The patient was treated initially with transarterial embolization in five stages, followed by vertex craniotomy and surgical resection of the AVFs. However, multiple additional DAVFs developed over the bilateral convexities, the falx, and the tentorium. Subsequent treatment entailed 15 stages of transarterial embolization; seven stages of transvenous embolization, including complete occlusion of the sagittal sinus and partial occlusion of the straight sinus; three stages of stereotactic radiosurgery; and a second craniotomy with aggressive disconnection of the DAVFs. Unfortunately, the fistulas continued to progress, resulting in diffuse venous hypertension, multiple intracerebral hemorrhages in both hemispheres, and, ultimately, death nearly 5 years after the initial trauma. Endovascular, surgical, and radiosurgical treatments are successful in curing most patients with DAVFs. The failure of multimodal therapy and the fulminant progression and disseminated nature of this patient's disease are unique.

Adult↗
PubMed2001

Endovascular treatment of intracranial aneurysms by using Guglielmi detachable coils in awake patients: safety and feasibility.

OBJECT: Embolization of intracranial aneurysms performed using Guglielmi detachable coils (GDCs) is performed with the patient in a state of general anesthesia at most centers. Such an approach does not allow intraprocedural evaluation of the patient's neurological status and carries additional risks associated with general anesthesia and mechanical ventilation. At the authors' institution, GDC embolization of intracranial aneurysms is performed in awake patients after administration of sedative and analgesic agents (midazolam, fentanyl, morphine, and/or hydromorphone). To determine the feasibility and safety of this approach, the authors have retrospectively reviewed their clinical experience. METHODS: The authors reviewed the medical records of all patients in whom GDC embolization for the treatment of intracranial aneurysms was undertaken between February 1, 1990 and October 31, 1999. Clinical presentation, medical comorbidities, anesthetic agents used, intraprocedural complications, and final procedural outcome were recorded for each patient. Guglielmi detachable coil embolization was attempted in the awake patient in 150 procedures. Among 92 procedures for unruptured aneurysms, 75 (82%) were completed without complications. Four procedures were completed with complications. Of the 92 procedures, 13 were aborted due to patient uncooperativeness (one patient), complications (three patients), morphological characteristics of the aneurysm or surrounding vessels that made embolization technically difficult (eight patients), or vasospasm (one patient). Among 58 procedures for ruptured aneurysms, the procedure was completed without complication in 48 cases (83%). The procedure was completed with complications in five cases and two patients required induction of general anesthesia during the procedure. Five procedures were aborted because morphological characteristics of the aneurysm or surrounding vessels made embolization technically difficult (two patients) or because of aneurysm rupture (two patients) or the appearance of a transient neurological deficit (one patient). CONCLUSIONS: Embolization of intracranial aneurysms performed using GDCs in the awake patient appears to be safe and feasible and allows intraprocedural evaluation of the patient. Potential advantages, including decreased cardiopulmonary morbidity rates, shorter hospital stay, and lower hospital costs, still require confirmation by a direct comparison with other anesthetic procedures.

Adult↗
PubMed2001

Europium fluorescence to visualize N-butyl 2-cyanoacrylate in embolized vessels of an arteriovenous malformation swine model.

BACKGROUND AND PURPOSE: Standard tissue staining using the lipid dye Oil-Red-O has been previously applied to stain vessel specimens, which were embolized with a mixture of n-butyl 2-cyanoacrylate (NBCA) and oil (Lipiodol). That technique, however, results in nonspecific and nonquantitative staining that does not provide the necessary differentiation between NBCA and Lipiodol. We present an innovative staining procedure that quantifies NBCA within treated tissues. METHODS: An arteriovenous malformation (AVM) model in swine was used to evaluate the polymerization characteristics of various ratios of Lipiodol/NBCA/glacial acetic acid (GAA) mixtures. To determine the depth of NBCA penetration within the AVM model and to characterize the polymerization patterns of various mixtures within the vessel, histologic cross- and longitudinal sections were prepared for microscopy. These paraffin-embedded tissue sections were stained with a europium aryl-beta-diketone complex (TEC) to improve differentiation between NBCA and Lipiodol. Quantification of NBCA and Lipiodol within the lumen of rete cross-sections was accomplished using image analysis software to determine percent luminal area occluded by embolization. RESULTS: Upon application of TEC, intense europium fluorescence was seen when the tissue samples were excited by low-power UV light (excitation at 365 nm; emission at 614 nm). The area of europium intensity within the lumen corresponded to NBCA concentration, and addition of GAA aided the NBCA distribution throughout the lumen without affecting fluorescence intensity. It was seen that NBCA could be easily differentiated from Lipiodol and that quantification could be readily performed on these sections because of the improved differentiation. For the case of a 50:50 (vol. %) mixture with an added 20 microL of GAA, luminal area distribution of Lipiodol, NBCA, and blood products was 42.6 +/- 3.5%, 33.8 +/- 5.7%, and 23.7 +/-2.7%, respectively. CONCLUSION: The rare earth metal europium, when added as a fluorescent chelate compound to histologic tissue sections, allowed for differentiation between NBCA and Lipiodol with good detail. These results have facilitated further characterization of NBCA polymerization for the use of AVM embolization.

Animals↗
PubMed2001

Using the flexibility index to compare batch and continuous activated sludge processes.

This paper considers the question of which is better: the batch or the continuous activated sludge processes? It is an important question because dissension still exists in the wastewater industry as to the relative merits of each of the processes. A review of perceived differences in the processes from the point of view of two related disciplines, process engineering and biotechnology, is presented together with the results of previous comparative studies. These reviews highlight possible areas where more understanding is required. This is provided in the paper by application of the flexibility index to two case studies. The flexibility index is a useful process design tool that measures the ability of the process to cope with long term changes in operation.

Bioreactors↗
PubMed2001

An overview of the posters presented at Watermatex 2000. III: Model selection and calibration/optimal experimental design.

This paper presents an overview of the posters presented in sessions 7 and 8 of the Watermatex 2000 conference. These posters present two aspects of modelling biological processes--model selection and calibration. Special attention is given to the papers on OED (Optimal Experimental Design), which is a method of optimising the data collection for model selection and calibration. The presence of these presentations at the conference highlights the continuing significance of modelling and stresses the requirement of improvements in modelling techniques. The papers provide some contribution to this end.

Calibration↗
PubMed2000

Horner's syndrome after carotid artery stenting: case report.

BACKGROUND: Angioplasty and stenting of various lesions of the carotid artery is gaining in popularity. Our knowledge of the efficacy and limitations of this promising technology is incomplete. Although Horner's syndrome and its variants have been described after traumatic, spontaneous, or surgical carotid dissection, it has not been reported after carotid artery stenting. CASE DESCRIPTION: A 36-year-old woman presented with left neck and ear pain and a 3-year history of rushing noises in her left ear. Angiography demonstrated evidence of dissection of the left internal carotid artery at the skull base with a pseudoaneurysm. The pseudoaneurysm was treated with a 6-mm diameter self-expanding stent in a 4-mm diameter left internal carotid artery. A few hours later, she developed partial Horner's syndrome with a subtle ipsilateral ptosis and miosis without anhidrosis. Angiography performed on the next day did not demonstrate further dissection or aneurysm growth but did show distention of the artery wall because of the stent. She did not develop any further sequelae. CONCLUSION: This case suggests that stretching of the artery wall may result in stretching of surrounding structures. The sympathetic fibers surrounding the internal carotid artery are clearly sensitive to this degree of stretch. Possible complications associated with stretch injury must be considered when choosing the stent diameter.

Adult↗