shukoor65/lab-rag-model huggingface dataset:
Circus movement atrial flutter in canine sterile pericarditis model. Activation patterns during entrainment and termination of single-loop reentry in vivo. BACKGROUND. Recently, we used a custom designed "jacket" electrode with 127 bipolar electrodes in a flexible nylon matrix to map the total atrial epicardial surface in the in situ canine heart. Atrial flutter in dogs with sterile pericarditis was shown to be due to a single wave front circulating around a combined functional/anatomic obstacle, with the arc of functional conduction block contiguous with one or more of the atrial vessels. METHODS AND RESULTS. In the present study, this model was used to analyze the activation pattern during pacing-induced entrainment and termination of single reentrant loops in a syncytium without anatomically predetermined pathways. Sustained atrial flutter was induced in five dogs with 3-5-day-old sterile pericarditis. Atrial pacing at a cycle length 5-30 msec shorter than the spontaneous cycle length entrained the arrhythmia and could result in a "classical" activation pattern, characterized by an antidromic stimulated wave that collided with the reentrant orthodromic wave front of the previous beat at a constant site. However, two variations of this classical activation pattern were also observed: 1) Pacing at short cycle lengths could lead to localized conduction block in antidromic direction, forcing a change in the pathway of the antidromic wave front. This could prevent the expected shift of the site of collision in antidromic direction. 2) The stimulated orthodromic wave front could also use a pathway different from that of the original reentrant impulse, so that a different circuit was active during the pacing period. Termination of atrial flutter by rapid atrial stimulation was associated with progressive slowing and finally blocking of the paced orthodromic wave front and a progressive shift of the site of collision in antidromic direction. The occurrence of conduction block was determined by the cycle length of stimulation and the number of stimulated beats. A longer train at the critical cycle length or the critical number of beats at a shorter cycle length could reinduce the same reentrant circuit or a different reentrant circuit, respectively, during stimulated cycles following the beat that terminated reentry. CONCLUSIONS. The epicardial activation sequence during entrainment of reentrant arrhythmias does not necessarily follow a standard activation pattern. Instead, the stimulated orthodromic as well as the antidromic wave front might use a pathway different from that of the original reentrant wave front. The mechanisms of termination, failure of termination, and reinitiation of single-loop reentry are similar to those in the "figure-eight" reentrant circuit.
The use of nasal calcitonin in the treatment of post-traumatic algodystrophy. Calcitonin is widely used in the treatment of algodystrophy but a major disadvantage is the need for its parenteral administration. For this reason, we evaluated the effect of 400 iu of nasal calcitonin in the treatment of post-traumatic algodystrophy in a prospective randomized double-blind study. We found no demonstrable effect on the clinical or skeletal progression of the disorder using sensitive methods of measuring the response to treatment. There was, however, a small but significant hypocalcaemic response in the treatment group despite no change in the other indices of bone turnover. Possible reasons for this lack of clinical and skeletal effect are discussed.
Blunt traumatic bladder rupture: the role of retrograde cystogram. STUDY OBJECTIVE: We evaluated the importance of microscopic and gross hematuria and the role of retrograde cystography and computed tomography (CT) in the diagnosis of blunt traumatic bladder rupture. DESIGN: All cases at a Level I trauma center between January 1, 1986, and March 31, 1989, were reviewed retrospectively. SETTING: Level I trauma center, university hospital. TYPE OF PARTICIPANTS: All patients with acute blunt abdominal trauma admitted to this Level I trauma center. INTERVENTIONS: The patients' charts were reviewed with emphasis on mode of diagnosis, treatment, and outcome. MEASUREMENTS AND MAIN RESULTS: Twenty-one patients had bladder rupture. All 21 had hematuria with more than 50 RBCs/high-power field, 17 gross and four microscopic. Twenty patients underwent retrograde cystography, which accurately identified bladder rupture, and one was found at laparotomy for other injuries. Seven patients had CT of the abdomen and pelvis, which failed to demonstrate bladder rupture. There were no associated urethral injuries in any of the patients with bladder rupture. CONCLUSION: Significant (more than 50 RBCs/high-power field) hematuria is the principal indication for evaluation for blunt bladder injury, and retrograde cystography is the diagnostic procedure of choice. CT is neither sensitive nor specific enough as primary diagnostic modality.
A novel mutation in the invariant AG of the acceptor splice site of intron 4 of the beta-hexosaminidase alpha-subunit gene in two unrelated American black GM2-gangliosidosis (Tay-Sachs disease) patients. Samples of genomic DNA from three unrelated American black infants having both biochemical and clinical features of classical infantile Tay-Sachs disease were sequenced following PCR amplification. A G----T transversion was observed in the AG acceptor splice site preceding exon 5 of the beta-hexosaminidase alpha-subunit gene in the first black family. This transversion changed the acceptor splice site from the consensus sequence, AG, to AT, thereby interfering with splicing at this intron 4/exon 5 junction. The proband was homozygous for this mutation; his mother and a brother are heterozygous. The same mutation was found in a second, apparently unrelated, black GM2-gangliosidosis patient. The second patient was a compound heterozygote, as only one allele carried this mutation. The mother and a brother in this second family are carriers for this mutation, while the father and a noncarrier sister are normal for this region of the gene. The third proband did not have this mutation; nor did the mother of a fourth black proband. Eight other independently ascertained non-black, non-Jewish, GM2-gangliosidosis families did not have this mutation. The observation of the same novel mutation in two unrelated black GM2-gangliosidosis patients indicates that the American black population has segregating within it at least one GM2-gangliosidosis mutation which may be specific to this population and not a result of migration.
Bopindolol: Czechoslovak experience with a new beta blocker in the treatment of hypertension. Bopindolol is a nonselective beta blocker with mild intrinsic sympathomimetic activity. One of the drug's main benefits is its prolonged effect, lasting for 24 hours, which makes it possible to administer bopindolol in a single daily dose, a fact that may improve patient adherence to therapy. A double-blind study was performed in two centers, comparing bopindolol with metoprolol in 86 hypertensive patients. Baseline diastolic blood pressure (BP) was 100 to 120 mm Hg. The effects of bopindolol or metoprolol on BP and heart rate were similar: return to normal values was achieved in 70% of patients with either drug. A 6-month study at another center found that bopindolol did not affect the levels of total cholesterol, low-density and high-density lipoprotein cholesterol or triglycerides. Another 12-month study documented a decrease in total cholesterol, apolipoprotein (apo) A1 and apo B. The apo A/B ratio rose, thus improving the atherosclerotic index. No deterioration of glucose tolerance or immunoreactive insulin response to glucose was seen after 6 months of bopindolol administration. Bopindolol satisfactorily modifies not only resting but also exercise BP during isometric and isotonic load, thus reducing BP fluctuation during physical activities of the hypertensive patient. The drug exerts no effect on renal and liver function, electrolyte balance and hematologic parameters. Bopindolol is a very useful drug of first choice in mild and moderate hypertension. Bopindolol's main advantages include its prolonged action, good tolerance and a beneficial effect on risk factors of atherosclerosis (lipid and carbohydrate metabolism).
Short and long term outcome of percutaneous transluminal coronary angioplasty in unstable versus stable angina pectoris: a report of the 1985-1986 NHLBI PTCA Registry. In a cohort of 1,720 consecutive patients from the National Heart, Lung, and Blood Institute, Percutaneous Transluminal Coronary Angioplasty (PTCA) Registry (August 1985-May 1986), we compared 768 patients (45%) with stable angina and 952 patients (55%) with unstable angina pectoris. Unstable angina patients exhibited at least one of the following characteristics: new onset angina, rapidly progressing angina, angina at rest, angina refractory to medication, variant angina, acute coronary insufficiency, or angina recurring shortly after an acute myocardial infarct. The distribution of single- and multi-vessel disease was similar among stable and unstable angina patients; multi-vessel disease predominated. Average severity of stenosis and incidence of tubular and diffuse stenosis morphology were higher among patients with unstable angina (both p less than 0.001). Patient success rates were similar in stable and unstable patients. However, on a per lesion basis, overall angiographic success rate and average reduction of severity of stenosis in successfully dilated lesions were significantly higher among patients with unstable angina (both p less than 0.001). Incidence of major patient complications (p less than 0.01) and of emergency coronary bypass surgery (p less than 0.05) were also higher in patients with unstable angina but consistent with their more precarious clinical condition and stenosis morphology. During a two year follow-up, the cumulative distributions of death, myocardial infarct, repeat PTCA, and coronary bypass surgery were not significantly different in patients with stable angina compared to patients with unstable angina. Comparison of the current PTCA Registry cohort with the cases reported in the 1979-1982 Registry revealed a 19% higher success rate for both stable and unstable angina patients. Major complication rates decreased between time periods for stable but not for unstable angina patients. Incidence of emergency bypass surgery decreased more for stable than for unstable angina patients. Coronary angioplasty is indicated in properly selected patients with unstable angina and both single- and multi-vessel coronary disease.
Experimental treatment of thrombotic vascular occlusion. The role of laser energy in the treatment of thrombotic vascular occlusion was evaluated in two sets of experiments. First, 10 polytetrafluoroethylene grafts were used to replace segments of the superficial femoral arteries in dogs and were thrombosed by distal ligation. Occlusion was maintained for one hour, or for 7, 14, 21, and 28 days in each of two grafts. Patency was restored in all 10 grafts without perforation or anastomotic disruption using a 2 mm hot tip probe powered by an Argon laser. However, increased organization of thrombus related to the duration of occlusion lead to decreased laser channel diameters, and 75% of the 28 day thrombus remained in the graft after recanalization. The second experiments tested the added benefit of thrombolytic infusion following laser recanalization. Bilateral external iliac artery thrombosis was induced in dogs by operative vessel isolation, de-endothelialization, and thrombin injection. At 7 days the efficacy of laser-assisted thrombolysis (LAT) versus enzymatic thrombolysis (ET) alone was compared. Eight vessels underwent ET by urokinase (4000 I.U./min.); 14 vessels were laser recanalized prior to thrombolytic infusion. LAT was performed from a carotid artery approach in 8 vessels (antegrade) and from a femoral artery in 6 vessels (retrograde). In contrast to studies using the hot tip alone, both ET and LAT accomplished complete thrombus removal. However, LAT lead to significant iliac arterial flow in 9 +/- 8 min. (antegrade) and 25 +/- 8 min. (retrograde) while ET required 109 +/- 47 min (p less than 0.01).
Fetal akinesia deformation sequence (Pena-Shokeir phenotype) associated with acquired intrauterine brain damage. An infant with Pena-Shokeir phenotype was born to a cocaine-using mother. The pathologic findings included polyhydramnios, facial anomalies, arthrogryposis, camptodactyly, pulmonary hypoplasia, and tetralogy of Fallot. The neuropathologic findings were diffuse brainstem and spinal cord neuronal degeneration and focal cerebral infarction, consistent with acquired intrauterine ischemic damage.
Elevated plasma chromogranin-A concentrations in prostatic carcinoma. Chromogranin-A is considered a sensitive immunohistochemical tissue marker in neuroendocrine prostatic carcinoma. We report that the plasma chromogranin-A level was elevated in 48% of 25 patients with stage D2 prostate cancer, and suggest that this marker can be used to monitor the clinical course of these patients.
Thoracic myelopathy caused by ossification of the ligamentum flavum. Clinicopathologic study and surgical treatment. The authors reviewed 14 patients with thoracic myelopathy caused by ossification of the ligamentum flavum (OLF). The predominant locality of symptomatic OLF was at the thoracolumbar junction, particularly at T10-11 followed by T11-12. At the level of the thickest OLF in each patient, there were three types of OLF from computed tomography and operative findings: a lateral type in 3 patients, diffuse in 8, and thickened nodular in 3. The diagnosis of OLF-related thoracic spinal canal stenosis was best made by enhanced computed tomography. Histologic study revealed that the developmental mode of OLF was mainly endochondral ossification. Numerous fibrocartilaginous cells were found in the increased and swollen collagen fibers forming the hypertrophic ligamentum flavum (HLF). Ossification extended along the superficial layer of HLF. The size or extension of OLF was relevant to the corresponding diathesis of spinalhyperostosis. Results of laminectomy for OLF were poor because of the high occurrence of complications early on or later deterioration. Therefore, laminoplasty is recommended as a successful procedure for OLF-related thoracic myelopathy, avoiding further local mechanical stress due to tensile force.
Significance of a negative exercise thallium test in the presence of a critical residual stenosis after thrombolysis for acute myocardial infarction. BACKGROUND. After thrombolytic therapy for acute myocardial infarction, increasing emphasis is placed on early submaximal exercise testing, with further intervention advocated only for demonstrable ischemia. Although significant residual coronary artery lesions after successful thrombolysis are common, many patients paradoxically have no corresponding provokable ischemia. METHODS AND RESULTS. The relation between significant postthrombolytic residual coronary artery disease and a negative early, submaximal exercise thallium-201 tomogram was studied among 101 consecutive patients with uncomplicated myocardial infarction and at least 70% residual stenosis of the infarct artery. A negative test occurred in 49 (48.5%) patients with a mean 88% residual infarct artery stenosis. Further characteristics of the group were as follows: mean time to treatment was 3.1 hours; mean age was 54 +/- 10 years; 80% were male; 47% had anterior infarction; 39% had multivessel disease; mean left ventricular ejection fraction was 53 +/- 14%; and mean peak creatine kinase level was 3,820 +/- 3,123 IU/ml. A similar group of 52 (51.5%) patients, treated within 3.3 hours from symptom onset, with a mean postthrombolysis stenosis of 90%, had a positive exercise test. Characteristics of this group were as follows: age was 58 +/- 10 years; 92% were male; 56% had anterior infarction; 40% had multivessel disease; and mean left ventricular ejection fraction was 54 +/- 15%. The peak creatine kinase level associated with the infarction, however, was lower: 2,605 +/- 1,805 IU/ml (p = 0.04). There was no difference in performance at exercise testing with respect to peak systolic pressure, peak heart rate, or time tolerated on the treadmill between the two groups. By multivariate logistic regression, only peak creatine kinase level predicted a negative stress result in the presence of a significant residual stenosis (odds ratio, 4.2; 95% confidence interval, 1.1-16.3). CONCLUSIONS. The explanation for the relatively frequent finding of a negative early stress 201Tl tomogram after apparently successful reperfusion appears to be more extensive myocardial necrosis and not delay in therapy or inadequate exercise performance.
Therapeutic effects of genetically engineered toxin (DAB486IL-2) in patient with chronic lymphocytic leukaemia. In DAB486IL-2 the receptor-binding domain of native diphtheria toxin is replaced by human IL-2 sequences. This recombinant fusion protein is selectively cytotoxic for cells bearing high-affinity IL-2 receptors--eg, leukaemic cells. A patient with chronic lymphocytic leukaemia who did not respond to gamma interferon and conventional antileukaemic drugs has responded to DAB486IL-2.
The prevalence of autoantibodies during third-trimester pregnancy complicated by hypertension or idiopathic fetal growth retardation. Lupus anticoagulant, anticardiolipin, antinuclear, anti-deoxyribonucleic acid, antithyroglobulin, and antithyroid microsomal antibodies were assayed during third-trimester pregnancy (100 normal, 100 with complications). In spite of a normal activated partial thromboplastin time in all instances, lupus anticoagulant was further investigated by three additional procedures: tissue thromboplastin inhibition time, platelet neutralization procedure, and cephalin neutralization test. The prevalence of autoantibodies in pregnancies with hypertension reaches 16% (four with lupus anticoagulant, two with anticardiolipin, and two with antithyroid microsomal antibodies), which is significantly greater than that for idiopathic fetal growth retardation (2%) (one with lupus anticoagulant antibodies) and normal pregnancies (3%) (two with antithyroglobulin and one with autithyroid microsomal antibodies) (p less than 0.01). Autoantibodies were equally distributed between patients with gestational hypertension and those with preeclampsia. When compared with the 42 patients with hypertension and no autoantibodies, the eight patients with autoantibody had a more frequent history of fetal growth retardation (p less than 0.05), but there was no difference in the severity of hypertension, the frequency of obstetric complications, or the outcome of pregnancy. They did not require any specific treatment.
Atrial fibrillation associated with autonomic dysreflexia in patients with tetraplegia. Atrial fibrillation is an arrhythmia characterized by disorganized atrial depolarizations and an irregular ventricular response. Most patients with atrial fibrillation have underlying cardiac pathology. This paper presents the cases of three patients with high-level spinal cord injury and symptoms of autonomic dysreflexia who developed atrial fibrillation without any cardiac or metabolic disease that would predispose them to this. The paper proposes that autonomic dysreflexia might predispose a patient to atrial fibrillation by altering the pattern of repolarization of the atria, making the heart susceptible to a reentrant type of arrhythmia. High-level spinal cord injured patients may be at increased risk for the development of atrial fibrillation, an arrhythmia which, if left untreated, can increase the incidence of an embolic cerebrovascular accident that could further impair the patient's functional status.
Selection of the approach to the distal internal carotid artery from the second cervical vertebra to the base of the skull. Although several approaches for exposure of distal internal carotid artery lesions have been reported, the precise anatomic levels for which each of these maneuvers are most appropriate have not been well described. Since these techniques may require preoperative preparation, it is useful to determine in advance how much exposure will be needed and to select the most suitable and effective technique. We used anatomic dissection in 12 human cadaver specimens (24 carotid bifurcations) to define the limits of distal internal carotid artery exposure by several commonly advocated methods. The standard anterior approach along the sternocleidomastoid muscle allowed exposure of the internal carotid artery to the level of the upper one third of the second cervical vertebra. The upper limit of this exposure was extended to the middle of the first cervical vertebra by division of the posterior belly of the digastric muscle. Anterior subluxation of the mandible increased the distal exposure of the internal carotid artery to the superior border of the first cervical vertebra. Styloidectomy in combination with the preceding maneuvers extended the exposure an additional 0.5 cm cephalad. Lateral mandibulotomy did not significantly extend exposure beyond that obtained with mandibular subluxation and styloidectomy. Exposure of the internal carotid artery in the 1 cm immediately below the base of the skull required a posterior approach with mastoidectomy.
Time course of creatine kinase release after termination of sustained ventricular dysrhythmias. Differentiation between primary and secondary (caused by acute myocardial infarction) ventricular fibrillation has important therapeutic and prognostic implications. The diagnosis of myocardial infarction is based on clinical, ECG, and creatine kinase MB isoenzyme (MBCK) activity. Enzymatic criteria might not be able to confirm the diagnosis of myocardial infarction after recent cardioversion. The routine use of electrophysiologic studies involving the induction and termination of ventricular dysrhythmias provides a setting in which enzyme release as a result of cardioversion alone can be examined. Therefore a systematic investigation of the magnitude and time course of creatine kinase (CK) and MBCK release was performed after termination of ventricular dysrhythmias in 57 patients undergoing electrophysiologic studies. Of patients requiring external cardioversion, only 50% had an elevation in CK and MBCK activity. Elevation when present corrected with the number of shocks and cumulative energy delivered. The magnitude of MBCK release exceeded 10% of the total CK activity in 9% of observations. Pace-termination of ventricular tachycardia did not result in enzyme release. Arrhythmia characteristics, coronary artery disease, and left ventricular function did not affect the magnitude of the time course of enzyme release. These data suggest that cardioversion with multiple shocks may result in a component of MBCK release, and thus a false positive diagnosis of primary acute myocardial infarction may be made by relying exclusively on the enzyme release pattern.
Lumbar regional anaesthesia and prophylactic anticoagulant therapy. Is the combination safe? A survey has been carried out in all Danish anaesthetic departments (n = 80) regarding the attitude towards the use of epidural/spinal lumbar analgesia in patients who were receiving prophylactic anticoagulant therapy for the prevention of thromboembolism. About 60% of the departments used the techniques in patients receiving low-dose heparin and no side effects had been experienced. Spinal and epidural anaesthesia were in general regarded as being contraindicated in patients fully anticoagulated with vitamin K antagonists. In the world literature, the attitude towards the combination is conflicting. No randomised trial has been performed and complications are almost entirely confined to patients fully anticoagulated with vitamin K antagonists. Only one case of an epidural haematoma has been recorded when subcutaneous low-dose heparin was used as thromboprophylaxis.