123rc/medical_text huggingface dataset:
Percutaneous support devices for high risk or complicated coronary angioplasty. Indications for coronary angioplasty have expanded to include patients with unstable acute ischemic syndromes, severe multivessel coronary artery disease and impaired left ventricular function. Several mechanical approaches have been developed as adjuncts to high risk coronary angioplasty to improve patient tolerance of coronary balloon occlusion and maintain hemodynamic stability in the event of complications. These percutaneous techniques include intraaortic balloon counterpulsation, anterograde transcatheter coronary perfusion, coronary sinus retroperfusion, cardiopulmonary bypass, Hemopump left ventricular assistance and partial left heart bypass. The intraaortic balloon pump provides hemodynamic support and ameliorates ischemia by decreasing myocardial work; it may be inserted for periprocedural complications or before angioplasty in patients with ischemia or hypotension. Anterograde distal coronary artery perfusion may be accomplished passively through an autoperfusion catheter or by active pumping of oxygenated blood or fluorocarbons through the central lumen of an angioplasty catheter. Synchronized coronary sinus retroperfusion produces pulsatile blood flow via the cardiac veins to the coronary bed distal to a stenosis. Both perfusion techniques limit development of ischemic chest pain and myocardial dysfunction in patients undergoing prolonged balloon inflations. Percutaneous cardiopulmonary bypass provides complete systemic hemodynamic support which is independent of intrinsic cardiac function or rhythm and has been employed prophylactically in very high risk patients before coronary angioplasty or emergently for abrupt closure. These and newer support devices, while associated with significant complications, may ultimately improve the safety of coronary angioplasty and allow its application to those who would otherwise not be candidates for revascularization.
Postinfarction ventricular septal defect repair: retrospective thoughts and historical perspectives. Evolution of surgical techniques for repair of postinfarction ventricular septal rupture initially involved differentiation of these lesions from prior experience with surgical approaches to congenital ventricular septal defects, which were in the main not applicable. Second, understanding of the differing anatomical locations of postinfarction ventricular septal defects required innovation in terms of the location of the cardiotomy and type of repair necessary to achieve a successful result in any given patient. The gradual appreciation of different clinical courses pursued by patients after postinfarction ventricular septal rupture both in terms of location of the defect and the degree of right ventricular functional impairment has led to increased urgency relative to the timing of surgical repair. The incorporation of specific anatomical concepts of surgical repair and better understanding of the time course of physiological deterioration of patients can ultimately lead to an integrated approach aimed toward improved salvage of patients suffering this catastrophic complication of acute myocardial infarction.
Cardiovascular disease risk profiles. This article presents prediction equations for several cardiovascular disease endpoints, which are based on measurements of several known risk factors. Subjects (n = 5573) were original and offspring subjects in the Framingham Heart Study, aged 30 to 74 years, and initially free of cardiovascular disease. Equations to predict risk for the following were developed: myocardial infarction, coronary heart disease (CHD), death from CHD, stroke, cardiovascular disease, and death from cardiovascular disease. The equations demonstrated the potential importance of controlling multiple risk factors (blood pressure, total cholesterol, high-density lipoprotein cholesterol, smoking, glucose intolerance, and left ventricular hypertrophy) as opposed to focusing on one single risk factor. The parametric model used was seen to have several advantages over existing standard regression models. Unlike logistic regression, it can provide predictions for different lengths of time, and probabilities can be expressed in a more straightforward way than the Cox proportional hazards model.
Effects of hepatitis B virus, alcohol drinking, cigarette smoking and familial tendency on hepatocellular carcinoma. Independent and interactive effects related to the development of hepatocellular carcinoma were assessed using a community-based case-control study for hepatitis B virus, habitual alcohol drinking, cigarette smoking, peanut consumption and history of hepatocellular carcinoma among the immediate family. All 200 male newly diagnosed hepatocellular carcinoma patients were recruited consecutively through the period of study as the case group from two teaching medical centers in northern and southern Taiwan. Healthy community residents matched one-to-one with cases on age, sex, ethnic group and residential area were selected as the control group. The carrier status of HBsAg and HBeAg was determined by blind radioimmunoassays, and other risk factors were obtained through standardized interviews according to a structured questionnaire. Conditional logistic regression analysis showed a significant association between hepatocellular carcinoma and the carrier status of HBsAg and HBeAg with an odds ratio of 16.7 and 56.5, respectively, for carriers of HBsAg alone and for carriers of both HBsAg and HBeAg. There was a dose-response relationship between cigarette smoking and hepatocellular carcinoma with an odds ratio of 1.1, 1.5 and 2.6, respectively, for those who smoked 1 to 10, 11 to 20 and more than 20 cigarettes a day. A significant association with hepatocellular carcinoma was also observed for the habitual alcohol consumer with an odds ratio of 3.4. Those whose immediate family had a history of hepatocellular carcinoma were more likely to have the disease develop, with an odds ratio of 4.6. However, the frequency of peanut consumption was not significantly associated with hepatocellular carcinoma.
Leishmania (Viannia) braziliensis: comparative pathology of golden hamsters infected with isolates from cutaneous and mucosal lesions of patients residing in Tres Bracos, Bahia, Brazil. The histopathology of primary forepaw and metastatic lymph node, spleen, and liver lesions produced in golden hamsters infected with cutaneous leishmaniasis (CL) strains (LTB 111 and LTB558) and mucocutaneous leishmaniasis (MCL) strains (LTB12 and LTB201) of Leishmania (Viannia) braziliensis isolated from patients residing in Tres Bracos, Bahia, Brazil is described. No pathological features providing clear differentiation of the CL and MCL strains were found. Although amastigotes were plentiful early in the development of primary forepaw lesions, they were either absent or could not be identified with certainty in sections of late stage lesions. Similarly, amastigotes were not found in histologic lesions at metastatic sites; however, leishmanial DNA was detected in both early and late stage forepaw lesions and metastatic lesions using Leishmania kinetoplast DNA and the gene coding for gp63 as hybridization probes. The DNA recovered from metastatic lesions was extracted from formalin-fixed paraffin-embedded tissues that had been stored at room temperature for prolonged periods.
Visually evoked potentials and electroretinography in neurologic evaluation. Electrophysiologic testing of the visual system requires primarily the ERG and the VEP. The flash electroretinogram provides information about the outer retina only. The pattern electroretinogram is derived from both the outer retina and the innermost retinal layers including the ganglion cell layer. The VEP is based on electrical information recorded from the visual cortex in response to stimulation of the retina. Thus, the integrity of the entire visual pathway can be tested. Localizing ability of the VEP is limited. Since the visual cortex is heavily weighted by representation of the central retina, peripheral lesions, including those producing peripheral visual field abnormalities that do not impinge upon central fixation, may produce relatively little disturbance of the VEP. As with most tests, electrophysiologic studies of the visual system must be placed in context of the entire examination, including the patient's history and neurologic and especially neuro-ophthalmologic evaluation. Electrophysiologic testing has three main uses in neurology. Pattern-reversal VEPs may be useful in detecting hidden visual loss in multiple sclerosis; VEPs and ERGs can distinguish function from organic visual loss; and VEPs and ERGs can be useful in the diagnosis of visual loss in nonverbal patients, especially in children.
Alexia without agraphia associated with spleniogeniculate infarction. Pure alexia, following an infarction in the distribution of the left posterior cerebral artery, is attributed to damage of the left occipital lobe and the splenium of the corpus callosum. We describe a case of pure alexia in a 57-year-old woman with infarction of the left lateral geniculate body and the splenium of the corpus callosum, a variation on this classic disconnection syndrome.
Myasthenia gravis. Myasthenia Gravis is a disorder of neuromuscular function resulting from an immunologically based premature destruction of acetylcholine receptors. The disease is characterized clinically by variable weakness accentuated by repetitive muscular activity and usually responding to the administration of acetylcholinesterase inhibitors. Myasthenia Gravis is a complex disease and requires understanding of the many facets of its natural history and immunological basis to ensure optimal individual patient management. The long-term goal is control of the immunological imbalance; treatment regimens include thymectomy, corticosteroids, azathioprine, and plasmapheresis. The common use of acetylcholinesterase inhibitors provides symptomatic relief during variable daily muscular activity. Disability due to myasthenia gravis is to a large extent reversible and death is preventable. Early recognition of myasthenia gravis and appropriate treatment are often rewarded by remission that may be permanent.
Correction of truncus arteriosus with truncal valvar stenosis or insufficiency using two homografts. Surgical correction of truncus arteriosus requires the creation of right ventricular to pulmonary artery continuity and closure of the ventricular septal defect. A variety of conduits have been used including valved and nonvalved. Despite a significant incidence of truncal valvar stenosis and insufficiency, this valve has seldom been replaced. We present 4 cases of truncus arteriosus with truncal valvar stenosis or insufficiency that were repaired using two valved homografts: one to create the pulmonary outflow tract and the other to replace the abnormal truncal valve. Two of these patients are doing well after 4 months. Another child survived the operation and did well for 2 months when she died suddenly. The last child died 14 hours postoperatively from low cardiac output syndrome secondary to diabetic hypertrophic cardiomyopathy. When truncal valvar abnormalities are present, the primary repair of truncus arteriosus in an infant should include replacement of the truncal valve. Total correction can be successfully achieved using two valved homografts, resulting in long-term palliation and freedom from thromboembolic events and the use of anticoagulants.
The rat glucagon gene is regulated by a protein kinase A-dependent pathway in pancreatic islet cells. A cAMP response element (CRE) has been identified in the proximal 5'-flanking region of the rat glucagon gene, and activation of the cAMP-dependent pathway in fetal rat intestinal cells leads to an increase in the levels of glucagon mRNA transcripts. In contrast, the human glucagon gene does not contain a similar CRE, and the results of studies using immortalized rat and hamster islet cell lines have suggested that glucagon gene expression may not be regulated by cAMP. To reconcile these observations, we have studied the control of glucagon gene expression. Incubation of primary rat islet cell cultures with forskolin in the presence of low (0.5 g/liter) or high (2.0 g/L) glucose resulted in a 2- to 3-fold increase in the levels of glucagon mRNA transcripts. Forskolin also stimulated the secretion and synthesis of immunoreactive glucagon. The importance of the protein kinase-A-dependent pathway in the regulation of glucagon gene expression was also examined in hamster islet InR1-G9 cells. Cotransfection of a glucagon-chloramphenicol acetyltransferase (CAT) fusion gene containing the glucagon CRE and a cDNA encoding the catalytic subunit of protein kinase-A resulted in stimulation of glucagon-CAT activity in hamster islet cells. Catalytic subunit cotransfection also activated somatostatin-CAT, but no activation of RSVCAT was detected. The results of these experiments suggest that the rat glucagon gene is regulated by a protein kinase-A-dependent pathway in the endocrine pancreas.
Reduction in incidence of inducible ventricular tachycardia after myocardial infarction by treatment with streptokinase during infarct evolution. The aim of this study was to determine whether intravenous streptokinase administered with or without oral aspirin to patients with evolving myocardial infarction reduces the inducibility of ventricular tachycardia at electrophysiologic study and thus the risk of sudden death in infarct survivors. Of 159 patients randomized at Westmead Hospital to the multicenter Second International Study of Infarct Survival (ISIS-2) after streptokinase and aspirin in acute myocardial infarction, 87 underwent electrophysiologic testing 6 to 28 days after infarction to determine their risk of subsequent ventricular arrhythmias (streptokinase 20 patients; aspirin 25 patients; streptokinase and aspirin 21 patients; both placebos 21 patients). Patients who underwent electrophysiologic testing had similar clinical characteristics to those of patients who did not. The stimulation protocol comprised up to and including four extrastimuli applied to the right ventricular apex at twice diastolic threshold. An abnormal result was defined as ventricular tachycardia with a cycle length greater than or equal to 230 ms lasting greater than or equal to 10 s. Ventricular tachycardia was inducible at electrophysiologic study in 8 patients who received placebo streptokinase, but in no patient who received active streptokinase (8 of 46 versus 0 of 41; p = 0.005, Fischer's exact test). Ventricular tachycardia was inducible in 4 patients who received aspirin therapy and 4 who did not (4 of 41 versus 4 of 46; p = NS). During a mean follow-up period of 39 +/- 9 months, there were no spontaneous episodes of ventricular tachycardia, ventricular fibrillation or witnessed sudden death in the streptokinase-treated group compared with three such events in the placebo-treated group (p = 0.13). When compared with placebo therapy, intravenous streptokinase substantially reduced the incidence of inducible ventricular tachycardia in infarct survivors. No similar benefit was attributable to aspirin therapy.
Post-traumatic intracerebral pneumatocele: case report. Pneumocephalus occurs in 0.5 to 1.0% of head trauma, but may also occur after neurologic surgery, or as a result of eroding infection or neoplasm. The pathophysiology involves the presence of craniodural fistula allowing ingress of air. A ball-valve mechanism may allow air to enter but not exit the cranium, or CSF leak permits air entrance as fluid leaves the intracranial space. While a "succession splash" is considered diagnostic of pneumocephalus, most patients have nonspecific signs and symptoms such as headache. Therefore, a high index of suspicion in a patient with recent head trauma is necessary. The diagnosis is made radiographically by CT scan. This is generally performed to rule out intracranial hematoma or cerebral contusion in head trauma, but will reveal even very small quantities of air to the unsuspecting physician. Therapy is often noninvasive, allowing the craniodural defect to heal spontaneously. Selected situations require immediate operative repair of the fistula.
Imaging the fetal brain in the second and third trimesters using transvaginal sonography. High-frequency transvaginal probes were used at 20-40 weeks' gestation to develop a systematic examination of the fetal brain. Modeling the procedure after the standard neonatal neurosonographic examination, we attempted to obtain three coronal sections (anterior, midline, posterior) and two sagittal sections (midsagittal, right or left parasagittal). In 70 normal patients, all planes were imaged with a similar frequency (74-76%) except for the posterior coronal plane, which was imaged 59% of the time. Among the first 35 cases, 17% had a complete study, compared with 71% of the second 35 cases. Transvaginal sonography established or changed the diagnosis in five of the 13 cases with central nervous system or other abnormalities. We recommend that a complete fetal neurosonographic examination include transvaginal sonography to complement and enhance the transabdominal examination, especially for cases in which a fetal abnormality is suspected.
When is a prognostic factor useful? A guide for the perplexed. Traditionally, a number of variables have been used to predict outcome in patients with early-stage breast cancer. These tests are simple to perform and relatively inexpensive. Recently, a number of new factors, eg, tumor proliferative index, nuclear DNA content, and amplification or overexpression of growth-promoting genes or oncogenes have been identified as potential predictors of outcome in patients with breast cancer. There is now increasing pressure to introduce such tests into routine clinical practice. How does a clinical practitioner identify which test, or group of tests, best predicts adverse outcome and whether any more clinically useful information is provided than with the use of more traditional factors alone? The aim of a prognostic test in breast cancer is to predict which patients are destined to develop a recurrence of cancer and those who are not. The prognostic usefulness of a test can be expressed in terms of relative risk (RR), which is the ratio of the risk of breast cancer recurrence in patients who test positive to the risk in those who test negative. Methodologic guidelines that should be satisfied by a study evaluating the predictive ability of a test include the following: (1) Was an inception cohort assembled? (2) Was the referral pattern described? (3) Were laboratory and clinical outcomes assessed in a blinded fashion? (4) Was complete follow-up achieved? (5) Was adjustment for extraneous prognostic factors carried out? (6) Were appropriate statistical methods used? An approach is suggested to help the clinician choose the test, or combination of tests, likely to discriminate between "high-" and "low-risk" patients in his/her own practice. The decision regarding what particular threshold value (risk) defined by a prognostic test (or series of tests) warrants adjuvant therapy for an individual patient is a complex one but should be based on a clear presentation of the risks and benefits to the patient.
Usefulness of d, I sotalol for suppression of chronic ventricular arrhythmias. Sotalol is a unique beta-blocking drug, possessing significant class III antiarrhythmic activity. The efficacy and safety of 2 doses of sotalol (320 and 640 mg/day, divided in 2 doses) were compared to placebo in a 6-week randomized, double-blind, multicenter study of 114 patients with chronic ventricular premature complexes (VPCs) at frequencies of greater than or equal to 30/hour. Sotalol significantly reduced VPCs in patients receiving both low (n = 38) and high (n = 39) doses, compared with patients (n = 37) receiving placebo (by 75 and 88%, respectively, vs 10%; p less than 0.001, sotalol vs placebo; p less than 0.05, high vs low dose). The individual efficacy criterion (greater than or equal to 75% VPC reduction) was achieved in 34% of low-dose and 71% of high-dose sotalol versus 6% of placebo-treated patients (p less than 0.003, sotalol vs placebo; p = 0.007, high vs low dose). Repetitive beats were suppressed 25% by placebo (difference not significant), 80% by low-dose (p less than 0.003) and 78% by high-dose sotalol (p less than 0.005). Sotalol decreased heart rate (by 24 to 25%, p less than 0.001) and increased PR (by 4 to 6%, p less than 0.001) and corrected JT intervals (by 12 to 13%, p less than 0.001), but did not change ejection fraction. Proarrhythmia (nonfatal) occurred in 3 sotalol and in 2 placebo patients. Nine discontinued therapy because of adverse effects (1 low dose and 8 high dose, p less than 0.02). In summary, sotalol is an efficacious antiarrhythmic drug for VPC suppression; in lower doses, it is somewhat less effective but better tolerated.
Endovascular management of arterial intimal defects: an experimental comparison by arteriography, angioscopy, and intravascular ultrasonography. To determine the feasibility of the endovascular management of intimal defects while comparing the accuracy of arteriography with angioscopy and intravascular ultrasonography, we developed an in vivo model of arterial intimal flaps. In 10 superficial femoral arteries of five anesthetized mongrel dogs, intimal flaps were constructed and then imaged by arteriography, angioscopy, and intravascular ultrasound. A flexible microbiopsy forceps was used to remove each intimal flap under angioscopic guidance. Arteriographic lumen diameters were measured and cross-sectional areas calculated. Corresponding measurements by angioscopy and intravascular ultrasound with reduction in luminal area at the flap were obtained by use of computerized planimetry. Uniplanar arteriography identified 60% (6/10) of the intimal flaps, whereas angioscopy and intravascular ultrasound demonstrated 100%. Lumen diameter (in millimeters) measured by arteriography (3.4 +/- 0.6) correlated significantly with measurements by angioscopy (3.5 +/- 0.5, r = 0.77) and intravascular ultrasound (3.5 +/- 0.6, r = 0.96). Similarly, lumen area (square millimeters) by arteriography (9.2 +/- 2.9) correlated with measurements by angioscopy (8.9 +/- 2.2, r = 0.82) and intravascular ultrasound (8.6 +/- 2.7, r = 0.91). Reduction in lumen area by the flap by angioscopy (37 +/- 7%) and intravascular ultrasound (33 +/- 8%) also correlated significantly (r = 0.72). The intimal flaps were removed successfully in all 10 arteries as confirmed by arteriography, angioscopy, and intravascular ultrasound. We conclude that the endovascular management of intimal defects is possible. Additionally, angioscopy and intravascular ultrasound accurately evaluate lumen diameter and area while providing direct assessment of intimal defects.
Precertification for percutaneous transluminal coronary angioplasty in Medicare beneficiaries: a melting pot or a need for better national standards? The Health Care Financing Administration has contracted with state peer review organizations (PROs) in its effort to assure the quality of services and eliminate unreasonable and inappropriate care provided Medicare beneficiaries. By law, each state PRO must select 10 procedures for precertification. Coronary angioplasty has been chosen by 45 PROs for precertification and criteria in each state were developed with the advice of local physicians. This report describes the findings of a survey of these precertification criteria in an effort to determine their variability and to compare the PRO criteria to published national criteria created by expert panels. Current precertification criteria of Medicare beneficiaries show significant variability in the priorities and the clinical practice of cardiologists in performing coronary angioplasty, despite established and published guidelines for its safe and efficacious use. It is likely that the establishment of locally based criteria for coronary angioplasty will be geographically uneven and probably have a less than expected impact on the care provided to Medicare beneficiaries.