shukoor65/lab-rag-model huggingface dataset:
Histopathologic validation of angioscopy and intravascular ultrasound. BACKGROUND. To establish a histopathologic basis for angioscopic and ultrasound image interpretation we studied 70 postmortem human arterial segments in vitro. METHODS AND RESULTS. We used 7- to 9-French fiber-optic angioscopes and 20- to 30-MHz intravascular ultrasound imaging catheters. Three observers assigned an angioscopic and ultrasound image classification to each vessel segment. The image and histological classification categories were then compared. The sensitivity, specificity, and accuracy of both methods separately or in combination for normal vessels were each greater than or equal to 95%. The predictive value was better for angioscopy than for ultrasound due to incorrect ultrasound interpretations of normal anatomy in the presence of thrombus. For stable atheroma the sensitivity, specificity, and accuracy of the individual methods were each greater than 90%. However, both angioscopy and ultrasound had classification errors in that disrupted atheroma was identified and classified as stable atheroma. Consequently, the predictive value was 74% for angioscopy and 78% for ultrasound. For disrupted atheroma the sensitivities for angioscopy and ultrasound were only moderate (73% and 81%, respectively), whereas the specificity, accuracy, and predictive value were each high (greater than 90%). For thrombus detection, the specificity, accuracy, and predictive value were high (greater than 93%) for each method. The sensitivity of angioscopy was 100%. However, sensitivity was lower for ultrasound (57%) due to false-negative interpretation of laminar clots in normal vessels and an inability to distinguish disrupted or stable atheroma from intraluminal thrombus. CONCLUSIONS. Contingency analyses showed that each imaging method alone or combined had significant agreement with the results obtained from histology (p less than 0.001). When assessing all cases in which angioscopy and ultrasound were concordant, there was a 92% agreement with the histological classification.
Systemic effects of collagen-impregnated aortoiliac Dacron vascular prostheses on platelet activation and fibrin formation. To minimize intraoperative blood loss a watertight knitted Dacron aortoiliac prosthesis has been developed by impregnation with bovine collagen. A potential disadvantage is that collagen may be associated with an increase in thrombus formation. We conducted a prospective randomized trial to study the systemic effects of collagen-impregnated prostheses and of aortoiliac operation as such on the coagulation mechanism during the first 10 days after operation. Forty-one patients randomly received either a collagen-impregnated (n = 20) or a nonimpregnated prosthesis (n = 21). Twelve patients who underwent cholecystectomies served as controls. Three markers of the coagulation mechanism were monitored: beta-thromboglobulin, fibrinopeptide A, and fibrin/fibrinogen degradation products. We found no significant differences in median beta-thromboglobulin, fibrinopeptide A, and fibrin/fibrinogen degradation product levels between patients in the collagen-impregnated prosthesis group and patients in the nonimpregnated prosthesis group. This indicates that collagen does not stimulate the coagulation cascade any more than conventional Dacron protheses do. In a comparison of patients who underwent aortoiliac reconstruction and patients who underwent cholecystectomies, the results indicated a significant increased platelet activation and fibrin metabolism in aortoiliac reconstruction group compared with the control group. Finally, we observed a significantly higher preoperative fibrin metabolism in patients with vascular disease than in control subjects. This difference is attributable to the high preoperative fibrin/fibrinogen degradation product values in patients with aortic aneurysms.
Exercise testing and training in patients with peripheral vascular disease and lower extremity amputation. Patients with peripheral vascular disease have a high risk of coronary artery disease. The risk is even greater when the peripheral vascular disease leads to lower extremity amputation. Exercise testing using lower extremity exercise has been the "gold standard" for screening for coronary artery disease, but many patients with peripheral vascular disease and those with amputations have difficulty doing this type of exercise. Arm exercise ergometry has been shown to be a safe and effective alternative for the detection of coronary artery disease in patients who cannot do leg exercise. This test has also been used to determine safe exercise levels and may be able to predict the ultimate level of prosthetic use in amputees. Exercise training with arm ergometry also improves cardiovascular efficiency and upper body strength in poorly conditioned patients. Studies are needed to appreciate fully the role of exercise testing and training in the recovery of these patients after amputation.
Short-term variation in abnormal antenatal fetal heart rate records. In a retrospective study the relation of reduced fetal heart rate variation to fetal acidemia was analyzed with a computerized system for numeric analysis. Between 1983 and 1987, 78 pregnancies were identified in which at least one record of the fetal heart rate had very low long-term variation. The outcome was analyzed to determine the numeric criteria of fetal heart rate variation that most efficiently detect a fetus that will die (preterminal) or is dying (terminal). Because fetal compromise was found on occasion to be associated with a slow sinusoidal fetal heart rate rhythm that increased measures of long-term variation. It was necessary to define a new index of short-term fetal heart rate variation (the 1/16 minute epoch-epoch variation). This was closely related to long-term variation (r = 0.9) but provided better detection of preterminal records as judged by metabolic acidemia at delivery or intrauterine death.
Presence of the terminal complement complex (C5b-9) precedes myelin degradation in immune-mediated demyelination of the rat peripheral nervous system. In this study, the terminal complement complex C5b-9 (TCC) was localized by immunocytochemistry at different clinical stages of experimental autoimmune neuritis. Deposits of TCC were found on the surface of Schwann cells and their myelin sheaths, and to some extent in the extracellular space at predilective sites of impending demyelination before onset of clinical signs and for a short period thereafter. Additionally, TCC was deposited on the surface of W3/13 positive leukocytes. No TCC immunoreactivity was seen in the distal stump of transected sciatic nerves 1 to 15 days after axotomy. The early and transient deposition of TCC on Schwann cells and myelin sheaths in experimental autoimmune neuritis before overt demyelination suggests that complement activation plays a pathogenic role in the initiation of immune-mediated myelin damage. The lack of TCC immunoreactivity after nerve transection excludes a nonspecific activation process. The signals involved in local TCC formation in demyelinating peripheral nervous system disorders have yet to be explored.
Median frequency--a new parameter for predicting defibrillation success rate. STUDY HYPOTHESIS: Current American Heart Association guidelines recommend immediate defibrillation of ventricular fibrillation. When this is unsuccessful, there are no guidelines to help determine the optimum time at which to defibrillate after the administration of an alpha-adrenergic agonist. Previous studies have shown that the median frequency of the ventricular fibrillation ECG signal correlates with myocardial perfusion during CPR. We hypothesized that median frequency could predict the success of defibrillation and thus accurately determine the most appropriate time at which to defibrillate during ventricular fibrillation. STUDY POPULATION: Twenty-two mixed-breed swine weighing more than 15 kg were studied. METHODS: Ventricular fibrillation was induced electrically, and the ventricular fibrillation ECG signal was analyzed using fast Fourier analysis. After ten minutes of ventricular fibrillation, mechanical CPR was begun. After three minutes of CPR, the animals received one of three alpha-adrenergic agonists and CPR was continued. Defibrillation was attempted three and one-half minutes after drug administration. The average median frequency 20 seconds before defibrillation was calculated. Sensitivity and specificity of median frequency with respect to defibrillation success were determined. RESULTS: A median frequency of 9.14 Hz had a sensitivity of 100% and a specificity of 92.31% in predicting the results of defibrillation in this model. CONCLUSION: The median frequency may serve as a valuable parameter to guide defibrillation therapy during ventricular fibrillation.
Cysts of the neuraxis of endodermal origin. Five colloid cysts of the third ventricle were compared with two spinal enterogenous cysts to examine the hypothesis that these entities have the same origin from primitive endodermal tissue. All the lesions showed cuboidal and columnar epithelium with mucus containing goblet cells and cilia. Immunohistochemistry for cytokeratin, EMA and CEA was positive in all the colloid cyst and enterogenous cyst epithelium. S-100 was focally positive in three of the colloid and one of the enterogenous cysts while vimentin and GFAP were negative in both. The anatomical distribution of both colloid and enterogenous cysts is reviewed. An illustrative case of an identical cyst within the fourth ventricle is presented. This suggests that the similarities between colloid and enterogenous cysts and the presence of identical lesions along the neuroaxis indicate that these structures are derived from primitive foregut endoderm.
Septicaemia and adrenal haemorrhage in congenital asplenia. Five patients developed overwhelming infection as a result of congenital asplenia, which was previously unsuspected in all cases. Each illness followed a fulminant course resulting in death within 24 hours. They illustrate the respective roles of Haemophilus influenzae infection (n = 4) and adrenal haemorrhage (n = 4) in this condition. We suggest a management protocol for screening infants with abnormalities of the atria or viscera with splenic ultrasound and examination of a blood film for Howell-Jolly bodies. Vaccination and prophylactic antibiotics should be considered for those at risk. Vigorous use of parenteral antibiotics and steroids in suspected infection is recommended.
Retrospective long-term follow-up analysis in 21 patients with chordomas of various sites treated at a single institution. Twenty-one patients with chordoma were treated at the Radiation Oncology Center, Mallinckrodt Institute of Radiology, between 1949 and 1986. Thirteen patients had sacrococcygeal tumors, five had clival tumors, two had nasopharyngeal tumors, and one had a lumbar spine tumor. Nine patients were treated with surgery alone, eight patients with subtotal resection and postoperative irradiation, and four patients with radiotherapy alone after biopsy. The 5- and 10-year actuarial survival rates were 74% and 46%, respectively. The 10-year actuarial survival rate was significantly better in patients treated with surgery alone or surgery and irradiation than in those treated with radiotherapy alone (52%, 32%, and 0%, respectively, p = 0.02). Although all patients ultimately suffered a recurrence, those with lumbosacral tumors treated with surgery and irradiation had a longer mean disease-free survival period (6.6 years) than those treated with surgery alone (4.1 years) (p = 0.08). Disease-free survival times of patients with base of the skull tumors was not significantly different between the treatment groups. Irradiation after resection of chordomas appears to increase the time to first relapse in lumbosacral tumors and should be considered after subtotal resection.
Middle meatus anstrostomy: patency rates and risk factors. Two hundred patients with chronic sinusitis were operated on using functional endoscopic sinus surgery (FESS) techniques. These patients were followed closely over 3 years. Patency of the endoscopic middle meatotomy was recorded using actuarial life-table methods. The overall patency rate of the endoscopic middle meatotomy was 93.55%, and the actuarial patency rate at 36 months was 87.47%. The presence of seasonal allergy with nasal polyps was the most important variable in predicting closure. Middle turbinectomy was the most important variable in predicting patency. Symptoms were evaluated by questionnaire at 1 year. Questionnaire data indicate that 96% of these patients are improved or asymptomatic.
Striatal function in normal aging: implications for Parkinson's disease. Central to several current theories of the etiology of Parkinson's disease is the premise that the nigrostriatal dopaminergic system degenerates with normal aging. Much of the evidence for this assertion has come from postmortem neurochemical studies. We have used L-6-[18F] fluoro-Dopa and positron emission tomography in 26 healthy volunteers (age range, 27-76 years) to examine striatal and frontal cortical tracer uptake. Data have been analyzed by using a graphical approach to calculate an influx constant (Ki) for L-6-[18F]fluoro-Dopa uptake into the caudate, putamen, and medial frontal cortex of each subject. In the population studied, there was no decline in Ki with age for any of these structures. A series of physiological measurements made on the older subjects also showed few significant changes with age. The positron emission tomographic findings demonstrate preservation of nigrostriatal dopaminergic function in normal aging. The pathological process causing Parkinson's disease may operate closer to the time of presentation than has been suggested.
Total peripheral artery occlusions: conventional versus laser thermal recanalization with a hybrid probe in percutaneous angioplasty--results of a randomized trial Increasing the primary success rate in recanalization of peripheral vascular occlusions is one aim of using laser techniques in the treatment of peripheral vascular disease. Although reports of lasers enabling recanalization after failure of guide wires have been numerous, direct comparisons of the success of the two techniques in a randomized trial have been few. The results of a randomized trial showed no statistical difference in recanalization of femoropopliteal occlusions between the conventional guide wire and hybrid laser probe. The number of patients with iliac occlusions was small and comparisons are difficult to make, but the findings suggest that the hybrid laser probe has little to offer. Immediate crossover to the alternative method allowed investigation of the relationship between the two methods in practice. Combining the two methods improved the primary success rate from 82% to 91% for femoropopliteal occlusions randomized to laser thermal recanalization and from 74% to 91% for those randomized to conventional recanalization.
Normal splenic size in infants and children: sonographic measurements. The purpose of this study was to establish guidelines for normal splenic size at different ages by using a simple and reproducible sonographic method. Two hundred thirty patients, from neonate to 20-year-old, had sonography because of abdominal and/or pelvic problems unrelated to the spleen. Findings on sonograms of the liver and kidneys were normal in all cases. Splenic size was measured by obtaining a coronal view that included the hilum, while the patient was breathing quietly. The greatest longitudinal distance between the dome of the spleen and the tip (splenic length) was measured and correlated with age, height, and weight. The following guidelines are proposed for the upper limit of normal splenic length based on this simple, easy to use, one-measurement technique: splenic length no greater than 6.0 cm at 3 months, 6.5 cm at 6 months, and 7.0 cm at 12 months, 8.0 cm at 2 years, 9.0 at 4 years, 9.5 cm at 6 years, 10.0 cm at 8 years, 11.0 cm at 10 years, 11.5 cm at 12 years, 12.0 cm at 15 years or older for girls, and 13.0 cm at 15 years or older for boys. Twenty-two patients with known abnormalities of the spleen were randomly selected and their splenic lengths compared with the proposed guidelines; in each case, the length of the spleen exceeded the upper limit of normal for that age. Normal values of a single measurement of the greatest longitudinal diameter of the spleen, from the dome to the tip measured at the hilum in the coronal plane, were obtained in patients from newborn to 20 years old.
Coronal alignment after total knee replacement. Maquet's line passes from the centre of the femoral head to the centre of the body of the talus. The distance of this line from the centre of the knee on a long-leg radiograph provides the most accurate measure of coronal alignment. Malalignment causes abnormal forces which may lead to loosening after knee replacement. We report a series of 115 Denham knee replacements performed between 1976 and 1981 using the earliest design of components, inserted with intramedullary guide rods. Patients were assessed clinically and long-leg standing radiographs were taken before operation, soon after surgery and up to 12 years later. In two-thirds of the knees (68%) Maquet's line passed through the middle third of the prosthesis on postoperative films and the incidence of subsequent loosening was 3%. When Maquet's line was medial or lateral to this, an error of approximately +/- 3 degrees, the incidence of loosening at a median period of eight years was 24%. This difference is highly significant (p = 0.001). Accurate coronal alignment appears to be an important factor in prevention of loosening. Means of improving the accuracy of alignment and of measuring it on long-leg radiographs are discussed.
Intrahepatic recurrence after resection of hepatocellular carcinoma complicating cirrhosis. To determine whether a careful evaluation of tumor extension by preoperative computed tomography scan after intra-arterial injection of ultrafluid lipiodol and by intraoperative ultrasound examination reduced the recurrence rate of hepatocellular carcinoma after resection, a series of 47 cirrhotic patients with a single tumor operated on from 1984 was studied. Alphafetoprotein level was less than 100 ng/mL in 26 patients (55%), size of the tumor was less than 5 cm in 28 patients (59%), and capsule was present in 30 patients (63%). The resection was performed with free margin measuring 1 cm or more. The overall cumulative survival rates at 3 and 5 years were 35% and 17%, respectively. Intrahepatic recurrence was observed in 28 patients (60%), located less than 2 cm from the resection margin in only four patients. The cumulative intrahepatic recurrence rate at 3 years was 81% and was significantly higher in patients with tumor greater than or equal to 5 cm and in patients with preoperative alphafetoprotein level of greater than or equal to 100 ng/mL. In this series the cumulative intrahepatic recurrence rate at 5 years was 100%. This high recurrence rate after resection, even with careful evaluation of tumor extension, indicates that liver transplantation might be envisaged for the treatment of cirrhotic patients with resectable hepatocellular carcinoma.
Body composition in ballet dancers measured by total body electrical conductivity. The purpose of this study was to describe the body composition of adolescent and young adult ballet dancers using total body electrical conductivity (TOBEC). We studied 112 female and 33 male dancers. The mean ages were 15.0 +/- 2.0 and 18.7 +/- 3.1 yr for females and males, respectively. The mean percent body fat (PBF) values were 20.1 +/- 3.6% for the females and 14.5 +/- 4.2% for the males. Age and pubertal development were not significantly related to PBF in the females. Age and pubertal status were significantly inversely related to PBF in the males. There was no difference in dance history, percent body fat, and abdominal/hip or waist/hip ratios in eumenorrheic vs amenorrheic dancers. Estimated calorie intake indicated that dancers with menstrual abnormalities had lower calorie intake than those with normal menses. This is the largest group of ballet dancers whose body composition has been studied. Our PBF measurements are higher than in previous reports using hydrodensitometry, which may have underestimated body fat by not accounting for the increased bone density in the lower extremities of dancers. Our data suggest that previous measurements of PBF in dancers are underestimates; these new data challenge our concept of PBF values in dancers.
Upper gastrointestinal bleeding following open heart surgery. Predominant finding of aggressive duodenal ulcer disease. We reviewed our experience with endoscopically evaluated severe upper gastrointestinal hemorrhage following open heart surgery. Of 4892 patients undergoing open heart surgery, 18 (0.4%) sustained upper gastrointestinal hemorrhage requiring endoscopic evaluation. Endoscopy identified the source of bleeding in all cases. No significant complications of endoscopy were observed. Duodenal ulcers (DUs) were found in 16 (89%) of cases and were felt to be the source of bleeding in 15 (83%). Aggressive features, such as multiplicity, large size, or distal location were associated with 13 (81%) of the DU cases. Complications necessitated endoscopic or surgical therapy in eight (44%) patients with DUs. We conclude that aggressive DU disease accounts for the majority of severe upper gastrointestinal bleeding following open heart surgery.
Efficacy of transrectal ultrasound for identification of clinically undetected prostate cancer. A total of 51 patients underwent transrectal ultrasound of the prostate before radical cystoprostatectomy for transitional cell carcinoma of the bladder. Each had a normal prostate by digital rectal examination, no history of prostatic adenocarcinoma and no invasion of the prostate by transitional cell carcinoma. Real-time and step-sectioned ultrasound images were interpreted at the time of sonography and results were compared to pathological examination of the step-sectioned prostate specimen. When adenocarcinoma was identified in the specimen, cancer volume was determined. Positive ultrasound scans consisted of those exhibiting hypoechoic lesions. Hypoechogenicity due to transurethral resection defects, benign hyperplasia, vascular structures or shadowing from calcifications was not considered positive. Of 51 patients 27 (52.9%) exhibited no abnormality on ultrasound and were free of cancer in the prostate specimen, while 8 (15.7%) demonstrated a hypoechoic lesion that was proved to be prostate cancer. Seven patients (13.7%) with normal transrectal ultrasound scans had adenocarcinoma of the prostate, while 9 (17.6%) had lesions on ultrasound but no cancer. Based on these results, transrectal ultrasound has a sensitivity of 53.3% and a specificity of 75%. Further analysis reveals that transrectal ultrasound is more accurate in the detection of cancers of greater than 0.20 cc in volume than those of 0.20 cc or less. Transrectal ultrasound also is more accurate in the detection of peripheral zone than transition zone cancers.