Ozonation as a clean technology for fresh produce industry and environment: sanitizer efficiency and wastewater quality

AIMS

Inactivating microbial contaminants in fresh produce commonly uses chlorine washing. The effectiveness of ozone was explored as an alternative to chlorine in produce washing for ensuring microbial safety while maximizing water reusability.

METHODS AND RESULTS

An ozone washing system was designed to permit continuous addition of contaminated produce and the reuse of washing water. The effectiveness of ozonation (<2 mg l(-1) ) was determined using Bacillus subtilis spores as a stricter measure of efficiency with processing time of 10 min. As a comparison, chlorine (c. 100 mg l(-1) ) was tested in parallel. Water quality characteristics, including chemical oxygen demand, total suspended solids, disinfectants concentration and microbial reduction were measured. Ozonation showed an average of 1·56 log reduction of B. subtilis spores on lettuce, while chlorination achieved a 1·30 log reduction. The effluents after ozonation demonstrated improved water quality, both in physicochemical quality and microbial quality compared to chlorination.

CONCLUSION

Aqueous ozone treatment is effective against microbial contaminants on fresh produce and enables extended use of washing water.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results provide significant data about ozone disinfection efficacy and its impact on the water reusability, which can facilitate the ozone utilization in the fresh produce production as an environmental friendly alternative.

The effect of customized insoles on the reduction of postwork discomfort

This study examined the effect of customized insoles in relieving postwork discomfort in healthy individuals whose jobs require long periods of standing and walking. CompuSole insoles were worn by 122 New York City Police Department officers for up to 5 weeks for an average of 7 hours per day. The officers walked an average of 3 miles per day. Before the study, one-fifth of the police officers in this study experienced foot pain or discomfort at the end of their workday; 15% had calluses, corns, or athlete's foot; 18% had sought treatment for a foot problem in the past; and 20% had worn foot orthoses. There was a significant reduction in tiredness in the feet at the end of the day after wearing the insoles, but no improvement in back or leg discomfort. At the end of the workday, 68% had less foot discomfort and 60% were more comfortable at work when wearing the insoles.

Treatment of deep cerebral venous thrombosis by local infusion of tissue plasminogen activator

BACKGROUND

Treatment of extensive intracranial venous sinus thrombosis with thrombolytic drugs is described, although the indications for and most efficacious technique for achieving thrombolysis remain uncertain. We report the successful lysis of superficial and deep venous system thrombosis by infusion of recombinant human tissue-type plasminogen activator (rt-PA) into the anterior superior sagittal sinus.

CASE DESCRIPTION

A 34-year-old man presented with headaches followed by decreased level of consciousness and left hemiplegia. Angiography showed thrombosis of the superior sagittal and both transverse and straight sinuses with extension into the internal cerebral veins. The superior sagittal sinus was catheterized via a transfemoral route and rt-PA, 25 mg, was infused. There was no significant change in the thrombosis. The catheter was left in place and rt-PA was infused at 1 mg/minute for 19 hours. Repeat angiography showed resolution of the thrombosis. The patient was placed on heparin and then coumadin. He recovered completely.

CONCLUSIONS

This report suggests that superselective infusion of thrombolytics into thrombosed intracranial venous sinuses can lyse intracranial venous sinus thrombosis. The thrombolytic agent must be infused for hours. The apparent successful lysis of clot in the deep venous system when infusion was into the superior sagittal sinus might be related to diffusion of rt-PA throughout the intracranial venous system or to improved venous outflow caused by lysis of clot in superficial dural sinuses.

Metallic Stents Deployed in Synthetic Arteriovenous Hemodialysis Grafts

OBJECTIVE

The purpose of our study was to review the success of metallic stent treatment of intragraft stenoses in patients with synthetic arteriovenous hemodialysis grafts.

MATERIALS AND METHODS

Between May 1993 and May 1997, 19 metallic stents were placed in 11 patients (seven women, four men; age range, 41-83 years) to treat elastic intragraft stenoses or graft dissections. Before stent placement, all patients had experienced multiple episodes of graft thrombosis, had very limited vascular access for hemodialysis, and were considered poor surgical candidates.

RESULTS

The technical success rate was 100%, and there were no procedural complications. Using life-table analysis, we found primary patency to be 36% at 6 months after stent placement, 12% at 12 months, and 12% at 18 months. Secondary patency was 91% at 6 months after stent placement, 71% at 12 months, and 47% at 18 months. The mean and median patencies per intervention were 4.2 and 3.6 months, respectively. Mean and median secondary graft patencies were both 14 months (range, 3 days-32 months). Puncture through the stents occurred during dialysis, causing stent distortion and fracture. Eight stents had a linear fracture suggesting compression contributed to the stent distortion. No clinically evident complications related to stent placement occurred.

CONCLUSION

Metallic stent deployment can salvage access in synthetic arteriovenous grafts by alleviating intragraft stenoses. Patency of intragraft stents is similar to venous stents used to treat other hemodialysis-related stenoses; however, fracture of Wall-stents occurs with prolonged graft use, especially in areas of needle punctures.

Identification of a sequence element from p53 that signals for Mdm2-targeted degradation

The binding of Mdm2 to p53 is required for targeting p53 for degradation. p73, however, binds to Mdm2 but is refractory to Mdm2-mediated degradation, indicating that binding to Mdm2 is not sufficient for degradation. By utilizing the structural homology between p53 and p73, we generated p53-p73 chimeras to determine the sequence element unique to p53 essential for regulation of its stability. We found that replacing an element consisting of amino acids 92 to 112 of p53 with the corresponding region of p73 results in a protein that is not degradable by Mdm2. Removal of amino acids 92 to 112 of p53 by deletion also results in a non-Mdm2-degradable protein. Significantly, the finding that swapping this fragment converts p73 from refractory to sensitive to Mdm2-mediated degradation supports the conclusion that the amino acids 92 to 112 of p53 function as a degradation signal. We propose that the presence of an additional protein recognizes the degradation signal and coordinates with Mdm2 to target p53 for degradation. Our finding opens the possibility of searching for the additional protein, which most likely plays a critical role in the regulation of p53 stability and therefore function.

Holmium: YAG laser endoureterotomy in the treatment of ureteroenteric strictures following orthotopic urinary diversion

The management of ureteroenteric strictures in patients who have undergone urinary diversion can be challenging. In those patients with an orthotopic neobladder, anastomotic ureteral strictures can be treated endoscopically using a retrograde or antegrade approach. The availability of small (7.5F) flexible ureteroscopes, as well as the use of the Holmium laser has facilitated the ability to precisely incise the stricture under direct endoscopic visualization (endoureterotomy). We describe our technique for laser endoureterotomy in patients with ureteroenteric strictures following orthotopic urinary diversion.

Methylphenidate treatment of negative symptoms in patients with dementia

This pilot study evaluated response of negative symptoms (NS) to methylphenidate in patients with dementia and relationships between NS, depression, and cognitive deficits in these patients. Consecutively admitted patients with NS and dementia--12 with dementia of Alzheimer's type and 15 with vascular dementia--were rated on severity of NS (SANS and PANSS-N scales), depressive symptoms (Ham-D), and cognitive impairment (MMSE) before and after treatment with methylphenidate. NS decreased significantly, and cognitive scores increased. A decrease in depression scores was nonsignificant after all variance attributable to NS was removed. NS, depression, and cognitive scores were not significantly intercorrelated. Results were similar for Alzheimer's and vascular dementia patients. Negative symptoms in dementia patients appear responsive to methylphenidate treatment. This effect may underlie putative changes in symptoms of depression observed by other researchers.

Safety and Efficacy of Once-Daily Captopril Plus Hydrochlorothiazide versus Nifedipine Gastrointestinal Therapeutic System in Black Patients with Mild to Moderate Hypertension

The safety and efficacy of captopril plus hydrochlorothiazide (HCTZ) were compared to nifedipine gastrointestinal therapeutic system (GITS) in 145 randomly assigned black patients with mild to moderate hypertension. Following a 4-week placebo lead-in, patients received captopril plus HCTZ 25/15 mg or nifedipine GITS 30 mg for up to 12 weeks. Upward dose titration was permitted at weeks 3 and 6. Mean seated systolic and diastolic blood pressures decreased 16.1 ± 13.5 mm Hg and 11.5 ± 7.4 mm Hg, respectively, with captopril plus HCTZ. Statistically similar decreases were observed with nifedipine GITS: systolic, 19.3 ± 12.2 mm Hg; diastolic, 13.8 ± 7.2 mm Hg. There were no clinically significant between-group differences in serum chemistries. Edema was reported in 20.3% of nifedipine GITS patients versus 1.4% of captopril plus HCTZ patients (p = 0.001). The two regimens were equally effective in controlling blood pressure in black patients; however, a higher incidence of edema occurred with nifedipine GITS compared to captopril plus HCTZ.

Extrahepatic portal vein stenosis in recipients of living-donor allografts: Doppler sonography

OBJECTIVE

The aim of this study was to describe the appearances obtained and the pitfalls involved with the use of Doppler sonography for detecting portal vein stenoses after surgery in 198 recipients of pediatric reduced-size transplants.

SUBJECTS AND METHODS

We analyzed sonographic and Doppler studies after surgery for 167 children (average, 2.5 years old) who were recipients of 198 left lobe or left lateral segment liver segments (79 living-donor allografts and 119 cadaveric grafts). Sonographic and Doppler studies were performed either on the basis of clinical evidence of portal hypertension or as part of a screening protocol. Demographic and surgical data were compared with the incidence of portal vein structure. We calculated pressure gradients from Doppler jet velocities and compared them with gradients measured manometrically from direct portography in 12 patients. Imaging criteria that indicated portal vein stenoses were (1) a visualized portal vein diameter of 2.5 mm or less, (2) an acceleration of flow at the stricture or a poststenotic jet of portal vein flow revealed by Doppler imaging, or (3) both. Stenoses meeting these criteria were verified by surgical or angiographic identification.

RESULTS

Seventeen (22%) portal vein stenoses were detected in recipients of the 79 living-donor liver transplants, whereas three (3%) were detected in recipients of the 119 cadaveric grafts (p < .005). The use of cryopreserved venous extension grafts was the most significant parameter of correlation (p < .025). Doppler sonography predicted the stenoses in all cases, although it overestimated the pressure gradients in all but one of the verified cases. Intrahepatic portal vein flow was frequently normal in the presence of significant extrahepatic portal vein stenosis.

CONCLUSION

Diagnosis of portal vein stenosis in recipients of living-donor allografts requires real-time visualization of the entire length of the portal vein, combined with spectral and color Doppler investigations of the portal and splenic veins and a search for collateral vessels. Visualization of each component alone may be insufficient. In our study, when care was taken to follow this procedure, sonography accurately showed all angiographically verified portal vein stenoses, although pressure gradients frequently were inaccurate. A protocol for periodic follow-up with real-time and Doppler sonography is crucial for pediatric patients to permit early identification of portal vein stenoses.

Intravascular stents in the management of acute superior vena cava obstruction of benign etiology

The purpose of our study was to report our experience with percutaneous placement of intravascular stents to relieve venous occlusion in patients with acute superior vena cava syndrome resulting from benign etiologies. Six patients ranging in age from 39 to 66 years received thrombolysis followed by placement of stents within the superior vena cava or received stent placement alone as emergency treatment for symptoms of acute superior vena cava obstruction. Treatment was successful in all patients, with establishment of a patent lumen angiographically, and patients experienced prompt symptomatic relief. Follow-up examination at intervals of 5 months to 2 years has demonstrated no evidence of reocclusion. Three patients have subsequently had central lines placed across the stented vena cava for vascular access. Percutaneous placement of intravascular stents to treat acute occlusion offered a safe and effective method of treatment in patients with superior vena cava syndrome resulting from benign causes.

Median arcuate ligament compression syndrome in monozygotic twins

Twin 27-year-old women had symptomatic mesenteric ischemia caused by median arcuate ligament compression. Arteriography demonstrated severe celiac artery stenosis in one twin, celiac artery occlusion in the other, and proximal superior mesenteric artery narrowing with retrograde filling from a meandering mesenteric artery in both. Division of the ligament and direct celiac artery revascularization completely relieved symptoms in both patients. Median arcuate ligament compression of the celiac and superior mesenteric arteries can result in mesenteric ischemia. Documentation of this unusual syndrome in monozygotic twins suggests that the responsible anatomic relationships are congenital.

Late outcome of multivessel coronary artery disease after angioplasty or bypass surgery

Background. Results from randomized trials to determine optimal treatment for patients with multivessel coronary disease are not yet available. Thus, the early and late outcomes of 191 PTCA and 221 CABG patients done in 1985-86 were evaluated. Methods and Results. CABG patients selected had more coronary risk factors and more severe coronary artery disease compared to PTCA patients. Comparison of the initial outcome showed that clinical success without major cardiovascular events was similar (93.7% for PTCA vs. 90.0% for CABG; p=n.s.). Five year followup was obtained in 99.0% of PTCA patients and 94.4% of CABG patients. In the PTCA group, 89.8% were alive, 4.8% had sustained an MI, and repeat revascularization was required in 46.8%. In the CABG group, 87.1% were alive, 3.2% had had a MI, and 3.5% required repeat revascularization. Statistical comparison demonstrated no difference between the groups in survival or late cardiac events, but rate of repeat revascularization was significantly higher for PTCA patients (p less than 0.0001). Incompleteness of revascularization (p<0.01) was independently associated with an increased need for repeat revascularization in the PTCA group. In the CABG group, depressed left ventricular function (p less than 0.001) and female sex (p<0.01) were associated with lower survival rates. An analysis of cost per patient showed that the strategies were comparable. Conclusions. PTCA and CABG in multivessel disease patients have similar early results and comparable rates of survival and late cardiac events. Significantly more repeat revascularization is required in PTCA patients to maintain these results.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary rotational ablation: initial experience in 302 procedures

OBJECTIVES

The aim of this study was to assess the utility of percutaneous transluminal coronary rotational ablation in the treatment of coronary artery disease.

BACKGROUND

Although numerous advances have been made in the treatment of coronary artery disease, there are lesions with complex morphology that are not amenable to current intravascular therapy.

METHODS

A consecutive series of 242 patients having 302 coronary rotational ablation procedures was analyzed. One hundred nineteen (49%) of the patients had previously undergone attempted coronary angioplasty, which was unsuccessful in 31 patients (13%). The left ventricular ejection fraction was normal in 196 patients (81%). The ablation procedure was attempted in 308 vessels and 346 lesions. Of the 346 lesions treated, 26 (7.5%) were classified as American College of Cardiology/American Heart Association type A, and 320 (92.5%) as either type B or type C.

RESULTS

Procedural success was achieved in 284 (94%) of the 302 procedures and 330 (95.4%) of the 346 lesions in which ablation was attempted. Five procedures (1.7%) were unsuccessful, but no cardiac event occurred during the hospital stay. A major cardiac event occurred in 13 cases (4.3%); 9 (3%) of these complications were due to the ablation procedure. Six patients sustained a Q wave myocardial infarction alone, two had a Q wave infarction and required emergency surgery and one needed emergency surgery but did not have a Q wave infarction. No procedural deaths were attributed to the ablation procedure. Follow-up has been obtained in 182 of the 242 patients at a mean interval of 9 +/- 5 months. Of the 182 patients, 174 (95.6%) were alive and free of myocardial infarction. Angiographic follow-up is available thus far in 87 patients. By combining angiographic and clinical outcome, an overall estimated restenosis rate of 37.4% (68 of 182) was calculated.

CONCLUSIONS

These data suggest that coronary rotational ablation can be performed on lesions with a variety of morphologic features with high initial success rates. The overall rate of restenosis is similar to that of balloon angioplasty.

Rotational ablation of balloon angioplasty failures

In this series, we evaluated the use of rotational ablation in stenoses that were previously refractory to balloon angioplasty. Forty-one stenoses were treated; in 26, the balloon did not adequately expand within the lesion and in 15 the balloon could not be delivered to the stenosis. Rotational ablation was technically successful in 40 of 41 (97.6%) of the lesions attempted. Twenty-four patients have been followed (mean time = 9 +/- 5 months) and the restenosis rate was similar to that of balloon angioplasty. Rotational ablation appears well suited and may be the treatment of choice for heavily calcified, severely angulated, and diffusely diseased vessels.

Lesion morphology and coronary angioplasty: current experience and analysis

From July 1, 1990 to February 28, 1991, 533 consecutive patients with 764 target vessels and 1,000 lesions underwent coronary angioplasty. Procedural success was achieved in 92.3%, untoward (major cardiac) events occurred in 3% (0.8% myocardial infarction, 1.3% emergency coronary bypass grafting and 0.9% both; there were no deaths). An unsuccessful uncomplicated outcome occurred in 4.7%. Lesion analysis using a modified American College of Cardiology/American Heart Association classification system showed that 8% were type A, 47.5% were type B and 44.5% were type C (36% of type B and 11% of type C were occlusions). Angioplasty success was achieved in 99% of type A, 92% of type B and 90% of type C lesions (A vs. B, p less than 0.05; B vs. C, p = NS; A vs. C, p less than 0.01). Untoward events occurred in 1.2% of type A, 1.9% of type B and 2% of type C lesions (p = NS). An unsuccessful uncomplicated outcome occurred in 0% of type A, 6% of type B and 7% of type C lesions (A vs. B, p less than 0.05; B vs. C, p = NS; A vs. C, p less than 0.05). Among the unsuccessful uncomplicated outcome group, occlusion occurred in 49%: 38% of type B and 59% of type C lesions. With B1 and B2 subtypes, success was obtained in 95% and 89.5% and untoward events occurred in 1.5% and 2.3% and an unsuccessful uncomplicated outcome in 3.7% and 8%, respectively. C1 and C2 subtyping showed success in 91% and 86%, untoward events in 1.3% and 6% and an unsuccessful uncomplicated outcome in 7.5% and 8.5%, respectively. Among the 764 vessels, success was obtained in 89.5% and untoward events occurred in 2.5% and an unsuccessful uncomplicated outcome in 8%. Assessment of lesion-vessel combinations showed a less favorable outcome with type C lesions and combinations of A-B, B-C and multiple (more than three lesions) type B and C vessels. Statistical analysis of morphologic factors associated with angioplasty success included absence of (old) occlusion (p less than 0.0001) and unprotected bifurcation lesion (p less than 0.001), decreasing lesion length (p less than 0.003) and no thrombus (p less than 0.03). The only significant factor associated with untoward events was the presence of thrombus (p less than 0.003). Predictors of an unsuccessful uncomplicated outcome included old occlusion (p less than 0.0001) and increasing lesion length (greater than 20 mm) (p less than 0.001), unprotected bifurcation lesion (p less than 0.05) and thrombus (p less than 0.03).

Feasibility and safety of transesophageal stress echocardiography

To determine the feasibility and safety of transesophageal stress echocardiography (TSE), 86 patients with chest pain syndrome were studied. The TSE test consists of transesophageal atrial pacing during simultaneous monitoring of left ventricular contractility by the use of transesophageal echocardiography. An octapolar pacing catheter attached to the transesophageal echoscope was used in conjunction with a cardiac stimulator to induce pacing-tachycardia. The optimal pair of electrodes was chosen from 13 possible combinations of the 8-electrode catheter. The pacing rate was increased until greater than or equal to 90% maximal age-predicted heart rate was reached or significant wall motion abnormalities were developed. The test was also stopped if ischemic electrocardiographic changes or progressive chest pain occurred. A successful TSE test was performed on 77 patients (90%). Twenty-one patients (24%) developed Wenckebach AV block during pacing that was resolved by intravenous atropine sulfate in all but one of them. The TSE test could not be completed in nine patients (10%) because we were unable to capture in four patients (5%), there were suboptimal images in three patients (3%), and two patients suffered intolerable epigastric discomfort (2%). Pacing-induced wall motion abnormalities were identified in 53 patients (69%). No serious complications were noted. We conclude that TSE is a feasible nonexercise stress test that can be performed safely in patients with suspected coronary artery disease.

Emergency coronary artery bypass surgery following failed balloon angioplasty: role of the internal mammary artery graft

During a 4-year period (1986-1989), 3,502 patients had percutaneous transluminal coronary angioplasty (PTCA) in our institution. One hundred nineteen (3.4%) patients required emergency coronary artery bypass graft surgery (CABG) because of abrupt vessel closure following PTCA. Factors associated with vessel closure included lesion angulation greater than or equal to 90 degrees (p less than 0.007), the presence of thrombus (p less than 0.02), or a long (greater than or equal to 2 cm) lesion (p less than 0.03). Of these 119 emergency CABG patients, 108 (91%) arrived in the operating room in a stable condition (group I) and 11 (9%) were in cardiogenic shock (group II). Five (45%) of the group II patients were admitted to the hospital with an acute myocardial infarction and all 11 patients had a higher incidence of multivessel disease (p less than 0.05) and lower left ventricular ejection fraction (p less than 0.001) than group I patients. The overall surgical mortality was 10.1%; however, in group I the mortality was 5.6% and in group II it was 54.5% (p less than 0.001). The vessel that abruptly closed ("culprit vessel") was the left anterior descending (LAD) in 60%, the right coronary artery in 27%, and the left circumflex in 13%. The internal mammary artery was utilized to bypass the culprit artery in 51 (43%) patients, including 50% of the culprit LADs. With group I culprit LAD patients, when the left IMA was the bypass conduit, there were no hospital deaths nor strokes and there was a 6.3% incidence of perioperative infarction.

Rotational ablation of chronic coronary occlusions

Rotational ablation was performed successfully in three chronic coronary occlusions. At 3 months follow-up, two of the three lesions were patent. These cases illustrate the overall advantages and unique technical aspects of this device.

Transesophageal stress echocardiography: detection of coronary artery disease in patients with normal resting left ventricular contractility

A new nonexercise test to detect significant coronary disease was prospectively evaluated in 36 patients with chest pain syndrome and normal left ventricular contractility. Transesophageal atrial pacing was used to provoke ischemia during monitoring of left ventricular contractility by transesophageal echocardiography. A 12-lead ECG was recorded. A TSE was abnormal if new segmental wall motion abnormalities developed. On the basis of the TSE results, patients were separated into normal (group 1, n = 16) and abnormal response (group 2, n = 20). Arteriography revealed significant disease in 21 patients, 19 from group 2 and two from group 1. Sensitivity and specificity of TSE were 90% and 93%, respectively, and those for pacing ECG were 43% and 100%, respectively. In addition, TSE accurately predicted the coronary artery perfusion bed involved. In 10 patients, Wenckebach AV block developed during pacing and resolved immediately by the administration of atropine sulfate. No serious complications were seen. Thus TSE is a highly sensitive and specific novel technique to detect significant coronary disease in patients with chest pain syndrome and normal resting left ventricular contractility.

Multiple coronary artery aneurysms in an adult associated with extensive thrombus formation resulting in acute myocardial infarction: successful treatment with intracoronary urokinase, intravenous heparin, and oral anticoagulation

A 37-yr-old white female was admitted to hospital with an evolving anterior myocardial infarction. Coronary arteriography revealed multiple aneurysms in the left anterior descending (and right) coronary arteries. In the left anterior descending artery, there was evidence of extensive thrombus formation. The patient was successfully treated with intracoronary urokinase, intravenous heparin, and oral warfarin. There was partial thrombolysis in 16 hr and complete thrombolysis noted 6 wk later. This case of multiple coronary aneurysms, secondary to presumed Kawasaki disease, is the first documentation of antemortem intra-aneurysmal coronary thrombosis treated successfully by thrombolytic and anticoagulant therapy.

Brachial rotational atherectomy

The brachial approach adds a new dimension to rotational atherectomy. The two cases presented included a large ectopic right coronary artery and a right internal mammary graft where both outcomes were successful. These cases demonstrate that the brachial approach can facilitate rotational atherectomy when greater guide support is necessary.

Clustering of colorectal neoplasia: characteristics of coexisting adenomas in patients with severely dysplastic polyps or invasive (malignant) polyps as compared to patients with benign adenomas or carcinomas

This study compared the size, histology and morphology of coexisting neoplastic polyps found in colonoscopy, and evaluated the clustering of these polyps in patients with either colorectal carcinoma, cancerous polyps or benign adenomas. Patients were divided by their most malignant form of neoplasia: Group A included 58 patients with early invasive cancerous polyps, and Group B included 73 patients with in situ carcinoma within an adenoma. Group C consisted of 335 patients with benign adenomas, and Group D had 289 patients with colorectal carcinoma. There were no significant differences between the four groups regarding sex, age and ethnicity. The cancerous polyps were significantly larger than the benign polyps. There were significantly (P less than 0.01) more patients with multiple (greater than or equal to 5) colonic lesions in Groups A or B than in Groups C or D. Coexisting polyps were much closer to the index growth, and demonstrated more severe dysplastic changes in the case of cancerous polyps than those associated with benign polyps or cancer. Based on our data we speculate that cancerous polyps are not merely a middle link in adenoma-carcinoma sequence, but rather mark a subset of patients who are especially prone to develop neoplastic changes in their colonic mucosa. These patients should be included in a more strict colonoscopic surveillance programme.

Atherectomy, stents and lasers. An annotated bibliography of recent references

This is an annotated bibliography of selected references on atherectomy, stents and lasers that have appeared in the literature since the particular issue of the Journal of Invasive Cardiology covering that device was published. It has been structured to include pertinent details about each citation, including the site at which the device was used (coronary or peripheral), the type of article in which the research was reported (clinical paper, case report, abstract, review, editorial), the number of subjects or procedures and lesions treated, the design of the study (case study, single group, group comparison, or randomized trial), acute and late results, and comments about the study and its findings.

Stents. An annotated bibliography of selected references

This is an annotated bibliography of selected references on stents. It includes 90 annotated references and 6 others that were not annotated. It has been structured to include pertinent details about each citation, including the site at which the device was used (coronary or peripheral), the type of article in which the research was reported (clinical paper, case report, abstract, review, editorial), the number of subjects and lesions treated, the design of the study (case study, single group, group comparison, or randomized trial), acute and late results, and comments about the study and its findings.

Evidence of hibernating myocardium by a new transesophageal echocardiographic technique

Reversal of resting wall motion abnormalities after successful coronary angioplasty were documented in a patient with the use of a novel approach to stress testing. Transesophageal stress echocardiography utilizes transesophageal atrial pacing to provoke myocardial ischemia while the left ventricular contractility is being monitored by means of transesophageal echocardiography. The potential use of this technique is illustrated in this report.

A new technique for direct percutaneous jejunostomy tube placement

We describe a case in which we employed a new method of using intraluminal balloon support for direct percutaneous placement of a jejunostomy tube. Standard interventional radiologic techniques and readily available equipment and materials were used.

Effects of caffeine ingestion on body fluid balance and thermoregulation during exercise

This study investigated the effects of caffeine supplementation on thermoregulation and body fluid balance during prolonged exercise in a thermoneutral environment (25 degrees C, 50% RH). Seven trained male subjects exercised on a treadmill at an intensity of 70-75% of maximal oxygen consumption to self-determined exhaustion. Subjects exercised once after caffeine and once after placebo ingestion, given in a double-blind crossover design. Five milligrams per kilogram body weight of caffeine followed by 2.5 mg.kg-1 of caffeine were given 2 and 0.5 h before exercise, respectively. Rectal temperature was recorded and venous blood samples were withdrawn every 15 min. Water loss and sweat rate were calculated from the difference between pre- and post-exercise body weight, corrected for liquid intake. Following caffeine ingestion, when compared with placebo, no significant difference in final temperature or in percent change in plasma volume were found. No significant differences were observed in total water loss (1376 +/- 154 vs. 1141 +/- 158 mL, respectively), sweat rate (12.4 +/- 1.1 vs. 10.9 +/- 0.7 g.m-2.min-1, respectively), rise in rectal temperature (2.1 +/- 0.3 vs. 1.5 +/- 0.4 degrees C, respectively), nor in the calculated rate of heat storage during exercise (134.4 +/- 17.7 vs. 93.5 +/- 22.5 W, respectively). Thus, in spite of the expected rise in oxygen uptake, caffeine ingestion under the conditions of this study does not seem to disturb body fluid balance or affect thermoregulation during exercise performance.

Balloon dilatation of symptomatic subacute intimal dissection presenting as restenosis

Repeat percutaneous transluminal coronary angioplasty (PTCA) for subacute intimal dissections that produce symptoms after a period of 1 month or more is reluctantly performed for fear of extension and abrupt closure. Patients were identified with demonstrated intimal dissections (intimal contrast staining or frank intimal flap) at the time of initial PTCA who returned a mean of 17.5 weeks (range 9 to 50) later with recurrent chest pain. Repeat angiography revealed luminal compromise due to dissection rather than restenosis in 22 patients. Of these, 17 underwent repeat PTCA. Elective bypass surgery without attempted PTCA was chosen in the other 5 patients because of extensive intimal dissections (greater than 2 balloon lengths) or involvement of critical branches. In the group of 17 patients who had repeat PTCA, 10 (group 1) had a frank intimal flap without persistent contrast staining after the initial PTCA, while 7 (group 2) had both persistent staining and a flap. Successful PTCA was performed in 13 of these 17 patients (76%). There were 2 abrupt closures and 2 unsatisfactory luminal openings. One of these patients required urgent coronary bypass surgery. All 10 group 1 patients had successful repeat procedures versus only 3 of 7 group 2 patients (p = 0.01). The 3 patients with the greatest degree of luminal compromise immediately after the initial PTCA had failed repeat PTCA attempts. These results suggest that repeat PTCA for subacute intimal dissections presenting as restenosis can be successfully performed in selected patients, and that the presence of contrast staining and the degree of luminal compromise by the dissection may be predictive of outcome.

Hepatic metastases: liposomal Gd-DTPA-enhanced MR imaging

Liposomal gadolinium diethylenetriaminepentaacetic acid (DTPA) encapsulated within 70- and 400-nm vesicles was tested as a contrast agent for magnetic resonance (MR) imaging of the liver in rats with hepatic metastases. Liposomal Gd-DTPA caused significant improvement in contrast between liver and tumor (P less than .005) on T1-weighted MR images. Smaller 70-nm liposomal Gd-DTPA vesicles caused greater contrast enhancement, reflecting the larger surface-area-to-volume ratio of the smaller vesicles. Liposomal Gd-DTPA-enhanced images permitted significant improvement in metastasis detection by five blinded radiologists (P less than .005). By comparison, free Gd-DTPA without liposomes caused a statistically significant reduction in contrast between tumor and liver and reduced lesion detection (P less than .01). Liposomal Gd-DTPA also resulted in sustained vascular enhancement for 1 hour after administration. The results suggest that paramagnetic liposomes may become a useful MR imaging contrast agent.