123rc/medical_text huggingface dataset:
Comparison of two levels of anticoagulant therapy in patients with substitute heart valves After cardiac valve replacement patients were blindly randomized into two groups, both receiving aspirin (330 mg) and dipyridamole (75 mg) twice daily and the oral anticoagulant acenocoumarol (Sintrom). An international normalized ratio of 2.0 to 2.99 was assigned to group A and 3.0 to 4.5 to group B; both groups were subsequently analyzed for thromboembolic and hemorrhagic complications. Final evaluation included 51 and 48 patients, respectively. The follow-up was 626 months for group A (12.3 months/patient) and 486 months for group B (10.1 months/patient). The frequency of thromboembolism was equal in both groups: one transient ischemic attack in group A (a rate of 1.92/100 patient-years) and two transient ischemic attacks in group B (a rate of 4.94/100 patient-years). There was, however, a statistical difference in bleeding complications between the two groups (p less than 0.02). Two patients bled in group A, a rate of 3.9% (3.8/100 patient-years), which represents an incidence of one episode each 25.6 years of treatment; 10 patients bled in group B, a rate of 20.8% (24.7/100 patient-years) representing an incidence of one episode each 4 years of treatment. We conclude that an international normalized ratio of 2 to 3 is safer than a ratio of 3 to 4.5 and confers good protection from thromboembolism when oral anticoagulant therapy is used conjointly with platelet function-inhibiting drugs in patients with mechanical substitute heart valves.
Vaccines and milk immunoglobulin concentrates for prevention of infectious diarrhea. Considerable progress has been made in the last decade in developing vaccines against the most important enteric infections. Two new, widely licensed vaccines (oral Ty21a and parenteral Vi) are available against typhoid fever, and new attenuated Salmonella typhi strains are ready for testing. An engineered live orally administered cholera vaccine, CVD 103-HgR, is undergoing clinical trials for safety, immunogenicity, and transmissibility in children in areas where cholera is endemic. Multiple candidate vaccines against rotavirus, Shigella, and enterotoxigenic Escherichia coli are in clinical trials. Newly acquired knowledge about pathogenesis and mucosal and cellular immunology, coupled with application of biotechnology, has already resulted in many candidates for vaccines, and more are expected to appear within the next few years.
Modification of atrioventricular node transmission properties by intraoperative neodymium-YAG laser photocoagulation in dogs. The purpose of this study was to test the feasibility of neodymium-yttrium-aluminum-garnet (Nd-YAG) laser photocoagulation of the atrioventricular (AV) node to control the ventricular rate during rapid atrial rhythms without creating AV block. In 12 dogs on normothermic cardiopulmonary bypass, short laser pulses were delivered to an area between the coronary sinus orifice and the site of the most proximally recorded His deflection until second degree AV block occurred at a paced atrial rate of 200 beats/min. Long-term effects on AV node function were followed up for 3 months. Three animals developed chronic high grade AV block. In nine animals with preserved 1:1 conduction, the mean (+/- SEM) critical atrial cycle length resulting in AV node Wenckebach periodicity increased from 183 +/- 6 to 261 +/- 24 ms (+43%), the mean RR interval during induced atrial fibrillation increased from 248 +/- 14 to 330 +/- 27 ms (+32%) and the shortest RR interval during atrial fibrillation increased from 215 +/- 11 to 275 +/- 20 ms (+28%). Laser effects were not reversed by isoproterenol infusion. Histologic examination of the irradiated area showed fibrotic changes in the AV node and fatty metamorphosis. This study suggests that 1) graded Nd-YAG laser photocoagulation of the AV node region in dogs results in long-term modification of anterograde AV node transmission properties; 2) 1:1 conduction during sinus rhythm usually remains preserved, but ventricular rate during rapid atrial rhythms is chronically reduced; and 3) progression to high grade AV block occurs in a minority of animals.
Sensory visual testing in idiopathic intracranial hypertension: measures sensitive to change. Management decisions in idiopathic intracranial hypertension (IIH; pseudotumor cerebri) are based on the presence and change of visual loss. To study this change, we evaluated tests of sensory visual function over time. We used the results of the right eye of 19 patients whose clinical status improved (decrease in papilledema grade), and compared the outcome measures of the initial and final examinations. Contrast sensitivity testing showed significant improvement in the middle and high spatial frequency targets. Snellen acuity and color tests did not change significantly over the same period. Both Goldmann and automated visual field grade significantly improved from the initial to the final visit, while the presence of a defect on confrontation visual fields did not. Numerical analyses of automated perimetry thresholds also showed significant improvement. Generalized loss, most pronounced on the nasal side of the visual field, was present on the initial examination. Generalized improvement followed, least in the central and inferior paracentral areas. Patients with IIH should be followed with contrast sensitivity testing and perimetry using a disease-specific strategy.
Reduction in infarct size by the phospholipase inhibitor quinacrine in dogs with coronary artery occlusion. It has been suggested that activation of tissue phospholipases may contribute to the development of ischemic cell injury. In the present study we sought to assess whether administration of the phospholipase inhibitor quinacrine would reduce the extent of myocardial necrosis after coronary artery occlusion. In open-chest, anesthetized dogs the left anterior descending coronary artery was ligated, and technetium-99-labeled albumin microspheres were injected into the left atrium to measure the area at risk. The animals were then randomly divided into a control group (n = 8) and a group receiving quinacrine (5 mg/kg intravenous bolus followed by a 40 micrograms/kg/min infusion for 6 hours; n = 9). The animals were killed 6 hours after occlusion, and the infarcted area was delineated by triphenyltetrazolium chloride staining. The extent of the risk region was similar in the two groups (32.3 +/- 2.1% of the left ventricle in control dogs and 34.2 +/- 3.4% in quinacrine-treated dogs). Infarct size was 86.4 +/- 8.8% of the risk region in control animals, whereas in treated dogs it averaged 62.3 +/- 6.4% of the risk region (p = 0.05). No differences were found in heart rate, arterial pressure, and rate-pressure product between the two groups. Thus administration of the phospholipase inhibitor quinacrine reduced the extent of myocardial necrosis in a model of fixed coronary artery occlusion. Preservation of membrane phospholipids, reduced formation of lipoxygenase metabolites, or both may mediate this phenomenon.
Improved postoperative course after spinous process segmental instrumentation of thoracolumbar fractures. This article compares the postoperative course of 40 patients who had Harrington instrumentation with 40 patients who had Harrington instrumentation and interspinous process segmental instrumentation of unstable thoracolumbar fractures and reviews the findings. The two groups of patients were otherwise homogeneous, and average operative time, total blood loss, and days to oral intake were similar for both groups of patients. On average, however, patients undergoing interspinous process segmental instrumentation were out of bed sooner (4.5 versus 7.7 days, P less than 0.0001), discharged sooner (32 versus 38 days, P less than 0.079), and brace-free earlier (2.1 versus 5.9 months, P less than 0.001) and had fewer fixation-related complications than did patients undergoing Harrington instrumentation alone. Comparison of average hospital costs documented a savings of $5,160 for the typical patient undergoing interspinous process segmental instrumentation.
Anaesthetic problems in ex situ resection of the liver. Ex-situ resection of the liver is a new surgical technique for treatment of liver tumours not amenable to conventional surgery. This paper describes the cardiovascular and metabolic changes that occurred in nine consecutive such patients. No severe haemodynamic or pulmonary complications occurred. Specific problems were encountered during the prolonged anhepatic period, which lasted an average of 5.96 (SD 1.46) hours. Significant metabolic and coagulation disorders occurred 2 to 3 hours after hepatectomy because of complete loss of hepatic function. The predominant findings during the anhepatic period were hypoglycaemia and severe metabolic acidosis, mainly from increased levels of lactic acid. Exogenous administration of dextrose 5% at an average rate of 188 ml/hour was necessary to maintain normoglycaemia, while correction of metabolic acidosis required 403 (SD 159.79) mmol of sodium bicarbonate, supplemented by hyperventilation. Tris-hydroxymethylaminomethane was used when sodium overload was thought to be a problem. There was a marked decrease of Factor V and fibrinogen, a moderate thrombocytopenia and fibrinolysis. The severity of these alterations was dependent on the duration of the anhepatic period and the primary function of the re-implanted liver.
Effect of mitral regurgitation and volume loading on pressure half-time before and after balloon valvotomy in mitral stenosis. Doppler pressure half-time (PHT) is frequently used to assess mitral valve area (MVA), but the reliability of PHT has recently been challenged, specifically in the setting of balloon mitral valvotomy when hemodynamics have been abruptly altered. The effect of volume loading both before and after balloon mitral valvotomy on computation of MVA by Gorlin and by PHT in 18 patients with high-fidelity micromanometer measurements of left atrial and left ventricular pressure was therefore examined. Echocardiographic MVA increased from 0.91 +/- 0.15 to 1.97 +/- 0.42 cm2 after valvotomy. Volume loading produced significant increases in left atrial pressure (16 to 23 before and 12 to 20 mm Hg after valvotomy), in cardiac output (3.7 to 4.1 before and 3.9 to 4.6 liters/min after valvotomy), and in mitral valve gradient (11 to 14 before and 5 to 7 mm Hg after valvotomy). These hemodynamic changes were associated with modest but significant decreases in PHT and increases in MVA estimated by 220/PHT (0.66 to 0.81 before and 1.64 to 1.96 cm2 after valvotomy), whereas the MVA by Gorlin was not affected in a consistent fashion by volume loading (0.85 to 0.89 before and 1.66 to 1.69 cm2 after valvotomy). The correlation between Gorlin MVA and 220/PHT was only fair (r = 0.73, p less than 0.001) and was significantly poorer among patients with greater than 1+ mitral regurgitation (r = 0.72) than among those with less or no regurgitation (r = 0.79) (p = 0.001 by analysis of covariance for mitral regurgitation effect).
Temporal bone: three-dimensional CT. Part II. Pathologic alterations. Three-dimensional (3D) surface renderings were obtained from routine axial computed tomographic (CT) images in 15 patients with a variety of complex temporal bone abnormalities. The 3D CT reformations served as an adjunct to conventional sectional CT examination. While no diagnosis was substantially changed because of the 3D CT images, they did provide a more global perspective in cases of large tumors and fractures and at the postmastoidectomy site. Three-dimensional CT surface reformations are now practical and may be potentially useful for visualizing temporal bone lesions characterized by complex destructive change.
Racial differences in the anterior circulation in cerebrovascular disease. How much can be explained by risk factors? The entry characteristics of 1367 patients enrolled into the Extracranial/Intracranial Bypass Study were examined to determine if site differences in intracranial and extracranial arterial lesions among racial groups could be explained by differences in risk factors. Blacks were more often hypertensive, diabetic, or cigarette smokers, while whites had higher systolic blood pressure and hemoglobin values. Orientals had the lowest prevalence of vascular risk factors. Despite these differences in risk factors, multivariate analysis showed race to be an independent and strong predictor of the location of cerebrovascular lesions. To our knowledge, this study is unique in documenting risk factors prospectively and systematically in three racial groups simultaneously. Although generalization is limited by possible biases related to patient selection, the results affirm previous tentative conclusions about the role of race in determining the location of cerebrovascular disease.
Coronary artery dissection--a case report. Coronary artery dissection, both spontaneous and catheter-induced, is associated with a significant morbidity and mortality. The authors present a case of a middle-aged woman with spontaneous right coronary artery dissection causing inferior wall myocardial infarction and left coronary artery dissection at the time of coronary arteriography. It is suggested that emergency aortocoronary bypass surgery be performed preceded by insertion of an intra-aortic balloon in acute evolving cases where coronary anatomy is favorable to limit infarction and avert loss of life.
Left ventricular diastolic dysfunction limits use of maximum systolic elastance as an index of contractile function. We tested the hypothesis that maximum systolic elastance (Emax) fails to detect a decline in left ventricular (LV) contractile function when diastolic dysfunction is present. Canine hearts were studied in an isolated blood-perfused heart apparatus (isovolumic LV); contractile dysfunction was produced by 60 or 90 minutes of global ischemia, followed by 90 minutes of reperfusion. Nine normal hearts underwent 60 minutes of ischemia, and five underwent 90 minutes of ischemia. After the ischemia-reperfusion sequence, developed pressure, pressure-volume area, and myocardial ATP level were significantly less than those at baseline in all 14 hearts. In the group undergoing 60 minutes of ischemia, LV diastolic pressure did not increase, whereas Emax decreased from 5.2 +/- 2.5 to 2.9 +/- 1.4 mm Hg/ml (p less than 0.05). In the group undergoing 90 minutes of ischemia, diastolic pressure increased (from 10 +/- 2 to 37 +/- 20 mm Hg, p less than 0.05), and Emax did not change significantly (from 5.1 +/- 4.3 to 4.3 +/- 2.5 mm Hg/ml). A second series of experiments was performed in 13 hearts with pressure-overload hypertrophy (aortic-band model with echocardiography and catheterization studies before the ischemia-reperfusion protocol). Five had evidence for pump failure, whereas eight remained compensated. After 60 minutes of ischemia and 90 minutes of reperfusion, developed pressure, pressure-volume area, and myocardial ATP level were significantly less than those at baseline in all 13 hearts. In the group with compensated LV hypertrophy, LV diastolic pressure did not change, whereas Emax decreased from 6.9 +/- 3.0 to 3.1 +/- 2.3 mm Hg/ml (p less than 0.05).
Cluster headache: the effect of low oxygen saturation The present study concerns the possible relationship between hypoxia and the generation of cluster headache attacks. Fifteen controls and 25 cluster headache patients were studied. The patients were allocated into two groups according to cluster headache stage, i.e. cluster or remission period. During the tests, all the subjects were asked to inhale 12% oxygen (88% N2) for 30 min, and the decreasing oxygen saturation (SaO2%) was monitored. Patients in the remission period showed nearly the same decrement of SaO2% as controls. At the end of the test, patients in the bout showed significantly less reduction of SaO2% than the controls. In 5 patients, the test was carried out both in and outside the cluster periods. The tendency to less decrement in oxygen saturation in the cluster phase was as marked with this comparison, but the difference between the groups was not significant, probably partly due to the low number of tests carried out. Only one patient got a typical attack. It seems that hypoxia of this magnitude per se is not the cause of attacks. The different pattern with respect to SaO2% following 12% O2 inhalation in cluster headache may be due to an abnormality in central regulation and/or chemoreceptor sensitivity.
Peptic ulcer disease. How to treat it now. Options for treatment of peptic ulcer disease are becoming more diverse. Most new agents are effective yet offer no real advantage over more traditional therapy. However, omeprazole (Prilosec) may be of benefit owing to its potent inhibition of acid secretion, but it is not yet approved for this purpose. Whether treatment of Helicobacter pylori infection will prove beneficial is not yet known, but the answer should be forthcoming. Finally, as with any disease process, alleviation of risk factors is always important. Appropriate counseling regarding use of nonsteroidal anti-inflammatory drugs and cigarette smoking is a necessity.
Magnetic resonance imaging contrast agents: theory and application to the central nervous system. The theoretical aspects of magnetic resonance (MR) imaging contrast agents are reviewed, and their current applications to the central nervous system (CNS) and their future applications are discussed. Profound differences exist between contrast agents used for MR imaging and computerized tomography (CT). In MR imaging, the contrast agents are not imaged directly but rather act on adjacent protons to shorten T1 and T2 relaxation times. This in turn results in signal intensity changes. The lanthanide metal, gadolinium, in the form of gadopentetate dimeglumine, has been found to be both safe and efficacious as the only currently approved contrast agent for MR imaging. Magnetic resonance imaging revolutionized the detection and treatment of disease affecting the brain and spine. Initially, it was thought that signal characteristics on MR imaging would allow differentiation of specific pathology. It was soon found that MR studies were able to detect more abnormalities but were less able to characterize them. The recent development of contrast agents for MR imaging has allowed this modality to surpass CT for the evaluation of most CNS lesions. At present, contrast-enhanced MR imaging is generally accepted as the study of choice for evaluating acoustic neurinomas, pituitary lesions, meningeal disease, primary and secondary brain tumors, active multiple sclerosis, intradural spinal neoplasms, intramedullary spinal disease, and postoperative states in both the spine and brain. Even when contrast-enhanced CT can detect the same abnormalities, evaluation of the lesions in multiple planes on MR imaging can sometimes yield invaluable information, especially prior to surgery. Future developments of contrast material for MR imaging include non-gadolinium compounds, intrathecal contrast media, cerebral blood flow and volume evaluation, and, possibly, antibody-labeled contrast agents.
Intraoperative coronary angiography using fluorescein. Intraoperative coronary angiography using fluorescein was applied to evaluate the patency of saphenous vein grafts just after completion of the distal anastomosis. By this technique, the area of the revascularized myocardium was well estimated in real time. This intraoperative direct-vision examination gives us more timely and precise information during coronary artery bypass grafting.
The changing clinical spectrum of thromboangiitis obliterans (Buerger's disease). Between 1970 and 1987, 112 patients were diagnosed as having thromboangiitis obliterans (TAO). The age was 42 +/- 11 years (mean +/- SD; range, 20-75 years); 23% were women, and 7% were more than 60 years old when they were first diagnosed. Ischemic ulcerations were present in 85 (76%) patients: 24 (28%) patients with upper-extremity, 39 (46%) patients with lower-extremity, and 22 (26%) patients with both upper- and lower-extremity lesions. Ninety-one (81%) patients had rest pain, 49 (44%) patients had Raynaud's phenomenon, and 43 (38%) patients had superficial thrombophlebitis. We were able to follow up 89 of the 112 (79%) patients for 1-460 months (mean follow-up time, 91.6 +/- 84 months). Sixty-five (73%) patients had no amputations, while 24 (27%) had one or more of the following amputations: finger, six (15%) patients; toe, 13 (33%) patients; transmetatarsal, four (10%) patients; below knee, 14 (36%) patients; and above knee, two (5%) patients. Forty-three (48%) patients stopped smoking for a mean of 80 +/- 105 months (median, 46.5 months; range, 1-420 months), and only two (5%) patients had amputations after they stopped smoking, while 22 (42%) patients had amputations while continuing to smoke (p less than 0.0001). The spectrum of patients with TAO is changing in that the male-to-female ratio is decreasing (3:1), more older patients are being diagnosed, and upper-extremity involvement is commonly present. In the 48% of patients who stopped smoking, amputations and continued disease activity were uncommon.
Microprocessor-assisted solvent-transfer system for gallstone dissolution. In vitro and in vivo validation. To improve the efficacy, safety, and convenience of contact dissolution of gallbladder stones, a microprocessor-assisted solvent transfer system was developed. The system's two pumps simultaneously infuse and aspirate solvent into and from the gallbladder at a high flow rate through a multilumen catheter. The microprocessor controls the pumps using a closed feedback loop control algorithm to regulate intragallbladder pressure to prevent solvent escape into the duodenum. Turbulent solvent flow at the catheter end in the gallbladder is designed to induce rapid stone dissolution and to suspend insoluble residue, thus promoting its aspiration. The system's response and gallbladder emptying capacity was 160-fold faster than the natural gallbladder emptying rate. The rate at which gallstones were dissolved by methyl tert-butyl ether using the system was compared with that achieved with a syringe pump. For 6 of 11 pairs of stones that totally dissolved, the mean dissolution time with the system was 10 +/- 6 minutes compared with 112 +/- 81 minutes for the syringe pump. In the 5 of 11 stone pairs which dissolved incompletely, insoluble residue was completely eliminated by the system in 21 +/- 9 minutes but not by the syringe pump even at 360 minutes. When the system was used in gallstone patients, solvent recovery was 99% +/- 1%, and the concentration of a nonabsorbable marker did not change, confirming the lack of appreciable absorption of methyl tert-butyl ether. These studies suggest that the microprocessor-assisted solvent transfer system is a device capable of safe, complete, and fully automatic contact dissolution of cholesterol gallbladder stones using methyl tert-butyl ether or similar solvents.
Postencephalitic acquired Tourette-like syndrome in a child. We report a 6-year-old girl who developed a Tourette-like syndrome following presumed herpes encephalitis. This case suggests that tics can be acquired in childhood and may be associated with lesions involving basal ganglia or limbic circuitry.
Bilateral reexpansion pulmonary edema following unilateral pleurocentesis. Acute ipsilateral pulmonary edema following reexpansion of the lung after pleurocentesis or pneumothorax is a well described entity. We report the unusual occurrence of bilateral pulmonary edema following unilateral pleurocentesis in a young male without heart disease. Various hypotheses regarding the mechanism of reexpansion pulmonary edema include increased capillary permeability due to hypoxic injury, decreased surfactant production, altered pulmonary perfusion and mechanical stretching of membranes. This case suggests that forces leading to ipsilateral reexpansion pulmonary edema also affect the contralateral lung.