shukoor65/lab-rag-model huggingface dataset:
Spontaneous internal carotid artery dissection shown by magnetic resonance imaging. We have reported a case of spontaneous dissection of the internal carotid artery, with MRI and angiographic findings. We conclude that MRI is a beneficial noninvasive test for the detection and study of carotid artery dissection.
Protein C activation following coronary artery occlusion in the in situ porcine heart BACKGROUND. Activated protein C, the body's natural anticoagulant, may play a role in protecting the heart during and following an occlusion of the left anterior descending coronary artery (LAD) in the porcine heart. METHODS AND RESULTS. Infusion of 1 unit thrombin over 30 seconds into the LAD of juvenile pigs produced a prolongation of the Xa clotting time (153 +/- 14%) in blood drawn from the anterior interventricular vein (AIV). The action of the anticoagulant was blocked by a polyclonal immunoglobulin G antibody directed against porcine activated protein C. A brief (30 seconds) occlusion of the LAD induced a similar prolongation of the Xa clotting time (138 +/- 11%), which was also blocked by the polyclonal antibody. To determine whether activated protein C helps sustain the heart during and following a 2-minute occlusion, three groups of pigs were studied: 11 controls, six receiving activated porcine protein C, and nine receiving a monoclonal antibody (HPC4) that blocks protein C activation. Relative to the controls, HPC4-treated animals recovered function, as measured by the maximum time derivative of left ventricular pressure and segmental shortening, more slowly and were not able to sustain this recovery. Animals receiving activated protein C recovered more quickly and sustained this recovery. CONCLUSIONS. These data indicate that an ischemic insult induces rapid activation of protein C in the coronary microcirulation and that blocking this activation impairs recovery.
Irregular coronary lesion morphology after thrombolysis predicts early clinical instability After successful thrombolytic treatment for acute myocardial infarction, recurrent ischemia and infarction may occur with little warning. Coronary lesion morphology was analyzed from angiograms performed in 72 consecutive patients at 1 to 8 days after streptokinase treatment for acute myocardial infarction and the data were evaluated in relation to the subsequent clinical course. All patients were clinically stable at the time of angiography and continued to receive heparin infusion for greater than or equal to 4 days after thrombolysis. The infarct-related artery was patent in 55 patients (76%). In the 10 days after angiography, 15 patients developed prolonged episodes of angina at rest; the condition of 4 stabilized with medical treatment, but 11 required urgent medical intervention (coronary angioplasty in 8 and bypass surgery in 3). There were no differences in age, gender, left ventricular function or extent of coronary artery disease between those patients who developed unstable angina and those who had a stable in-hospital course. However, the median plaque ulceration index of the infarct-related lesion was 6.7 (95% confidence limits 6.3, 10) in the 15 patients with an unstable course versus 3.3 (2, 4.4) in those with a stable course (p less than 0.001). There were no differences between the two patient groups in the severity of stenosis, length of diseased segment, symmetry/eccentricity, presence of a shoulder, location at branch point or bend, presence of globular or linear filling defects, contrast staining or collateral supply. These data show that after thrombolysis, the degree of irregularity of the infarct-related artery is a critical determinant of early clinical instability.
Predominant T cell receptor V gene usage in patients with abnormal clones of B cells. We have examined alpha/beta V gene segment usage of peripheral blood CD4+ and CD8+ T cells, respectively, from patients with multiple myeloma and monoclonal gammopathy of undetermined significance, by using T cell receptor (TCR) for antigen monoclonal antibodies (MoAbs). In 7 of 16 patients we found an increase in the usage of various TCR V gene segments. The expansion was confined to either the CD4+ or the CD8+ T-cell subset, except for one patient where an abnormal pattern was observed both within the CD4+ and CD8+ T-cell subsets. In one patient 47%, and in another patient 30% of the CD8+ lymphocytes reacted with alpha V12.1 and beta V6.7 antibodies, respectively. In two other patients 29% and 40% of the CD4+ lymphocytes reacted with beta V6.7 and beta V8.1 antibodies, respectively. We conclude that T cells with a predominant V gene usage is a frequent feature in patients with abnormal clonal B cells of malignant or benign types. T- and B-cell populations are normally clonally linked in regulatory circuits. An abnormal proliferation of B cells might therefore induce, or be regulated by, an expansion of clonal T cells, as suggested by the present results.
The B-cell antigen receptor of the five immunoglobulin classes. Several proteins associate with surface IgM to form the antigen receptor. We show that just two, the alpha and beta associated chains, are sufficient to reconstitute an IgM surface receptor in fibroblasts. Contrary to expectation, a common alpha chain associates with all five immunoglobulin classes. We propose that B-cell antigen receptors consist of a common alpha/beta heterodimer associated with each immunoglobulin class. But the classes differ both in the glycosylation of their associated alpha chain and in their dependence on alpha/beta for surface transport.
Echocardiographic prediction of left ventricular volume after myocardial infarction. Left ventricular volume is a strong determinant of survival after acute myocardial infarction. The aim of this study was to determine which clinical and echocardiographic criteria assessed early after myocardial infarction would predict later left ventricular dilation. Forty-eight patients with uncomplicated transmural myocardial infarction had echocardiography 5 to 10 days after myocardial infarction and assessment of clinical variables including peak creatine kinase and sum of electrocardiographic ST segment elevation. Left ventricular dimensions were measured from the echocardiogram in the parasternal view and also in the apical four and two chamber views at the level of the mitral leaflets, papillary muscles and apex. A cardiac wall motion score was obtained by segmental analysis of the apical views. Echocardiographic left ventricular volume was measured after 1 year from the apical views with use of a Simpson's rule method. Initial clinical and echocardiographic variables were correlated with the left ventricular volume at 1 year. There was a significant relation between the initial four and two chamber end-diastolic dimensions and the left ventricular volume at 1 year, particularly for dimensions measured at the apical level (four chamber R2 = 0.66, p = 0.0001, two chamber R2 = 0.61, p = 0.0001). Other clinical variables, parasternal left ventricular dimensions and cardiac wall motion score were not significantly related to left ventricular volume. A powerful three variable model obtained by multiple regression and including the initial two chamber apical dimension, cardiac wall motion score and body surface area accounted for 82% of the variation in left ventricular volume at 1 year.
Hyperinsulinemia or increased sympathetic drive as links for obesity and hypertension. The association of obesity with hypertension has been amply demonstrated in cross-sectional, longitudinal, and dietary-intervention studies, but the mechanisms remain enigmatic. Both conditions are independently characterized by similar metabolic alterations, i.e., glucose intolerance, dyslipoproteinemia, elevated serum uric acid, and inadequate Na+ transport. Obesity, hypertension, and these metabolic alterations are associated with hyperinsulinemia/insulin resistance. The degree of these alterations is lowest in lean hypertensives, intermediate in obese normotensives, and greatest in obese hypertensives, but mortality risk is highest in lean hypertensives. This apparent discrepancy may be related to the divergent hemodynamic characteristics, possibly indicating different etiology, of lean and obese hypertensives, i.e., contracted blood volume, increased total vascular peripheral resistance, and normal sympathetic drive in the former, expanded blood volume, normal peripheral resistance, and increased sympathetic drive in the latter. Current knowledge suggests that the interrelationships of obesity and hypertension with the metabolic alterations could be mediated by high carbohydrate and fat consumption and low physical activity, resulting in obesity and separate pathways in hyperinsulinemia and increased sympathetic drive, leading to a double vicious cycle. In one, hyperinsulinemia and the consequent insulin resistance would compound one another. In the second, the increasing hyperinsulinemia would increasingly stimulate the sympathetic nervous system. This double vicious cycle could result in increasing hemodynamic and metabolic derangements causing hypertension, diabetes, and atherosclerotic cardiovascular disease (ASCVD). The association of lean hypertension with ASCVD may be through other mechanisms, e.g., hemodynamic forces on the vascular endothelium.
Inhibition by a new bisphosphonate (AHBuBP) of bone resorption induced by the MBT-2 tumor of mice. A new bisphosphonate, 4-amino-1-hydroxybuthylidene-1,1-bisphosphonate (AHBuBP), was compared with 3-amino-1-hydroxypropylidene-1,1-bisphosphonate (AHPrBP) and 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) in terms of its effect on tumor-induced osteolysis using a bladder tumor in mice (MBT-2). Tumor cells were inoculated subcutaneously (SC) over the calvaria in mice, resulting in a local tumor causing fragmentation of the bone. The tumor-induced osteolysis associated with osteoclasts proliferation was accompanied with reactive new bone formation. This osteolysis was evaluated by measuring the increased area of bone resorption in reduced opacity to radiograph and histologic study. The results showed the following sequence of potency: AHBuBP greater than AHPrBP = HEBP. This inhibition was obtained with no apparent effect on the growth of the MBT-2 tumor. The authors conclude that AHBuBP appears to be an interesting new bisphosphonate with possible clinical application.
Strategies for diagnosis and treatment of children at risk for occult bacteremia: clinical effectiveness and cost-effectiveness. Decision analysis was used to evaluate the probable health benefits, complications, and costs of six management strategies for febrile children at risk for occult bacteremia. The strategy that combined blood culture with empiric oral antibiotic treatment for all patients was predicted to prevent the highest number of major infections and to have the lowest cost per major infection prevented. The strategy that combined a leukocyte count and blood culture for all patients, followed by empiric antibiotic treatment for those with leukocyte count greater than or equal to 10,000/mm3, had almost equal cost and clinical effectiveness and avoided many antibiotic complications. Culture of blood specimens from all patients and no empiric treatment constituted the third most clinically effective intervention but was the least cost-effective in this model. Giving a 2-day oral course of amoxicillin without testing had the lowest average cost per febrile patient but was the least clinically effective intervention. However, the low degree of effectiveness of empiric treatment alone was based on the assumption that oral amoxicillin therapy was only 20% effective in preventing major infections after bacteremia. At higher estimates of effectiveness, treatment alone became a more viable strategy. We conclude that approaches which combine blood culture with empiric antibiotic treatment are the most clinically effective and the most cost-effective strategies for children at risk for occult bacteremia.
Functioning insulinoma--incidence, recurrence, and long-term survival of patients: a 60-year study. For the 60-year period from 1927 through 1986, we assessed the incidence, recurrence, and long-term survival among all Mayo Clinic patients with histologically confirmed functioning insulinoma. With use of the complete medical record system at Mayo and the comprehensive epidemiologic data base of residents of Olmsted County, Minnesota, we found 224 patients in whom an initial pancreatic exploration at Mayo had confirmed the presence of insulinoma. The median age (and range) of these patients at surgical diagnosis was 47 (8 to 82) years, and 59% were female patients. During the study period, eight cases of insulinoma occurred among residents of Olmsted County; their age and gender distributions were similar to those of the total cohort. The incidence of insulinoma among residents of Olmsted County increased during the study period to a stable level during the last 2 decades of 4 cases per 1 million person-years. For the total cohort, 7.6% had multiple endocrine neoplasia type I (MEN I), and 5.8% had malignant insulinoma. The risk of recurrence was greater among patients with MEN I (21% at 10 and 20 years) than in those without MEN I (5% at 10 years and 7% at 20 years). Although survival of the total cohort was not significantly impaired, it was significantly worse than expected for patients with malignant insulinoma (29% versus 88% expected at 10 years postoperatively). We conclude that insulinoma is less rare than previously suspected. After successful surgical removal, the long-term risk of recurrent insulinoma is relatively high in patients with MEN I; for patients with benign disease, the long-term survival is normal.
A comparative analysis of mass transport models in peritoneal dialysis. To better understand the differences in published estimates of peritoneal mass transport coefficients, a comparative analysis of seven mathematical models of peritoneal transport was performed. Uniform investigation involving measurements of solute concentrations and accurate determination of peritoneal dialysate volume was undertaken in twenty-eight 6 hour dwell studies using 3.86% glucose dialysate in non-diabetic patients undergoing continuous ambulatory peritoneal dialysis (CAPD). The investigated models were all based on the theory of transport across a homogeneous membrane. Diffusive mass transport coefficients (KBD) calculated during a period of dialysate isovolemia served as reference values in the comparative analysis. The evaluation of models involved calculations of transport coefficients and comparison of calculated dialysate-to-plasma concentration ratios (D/P) with experimental D/P. The best fit of theoretically predicted D/P to experimental D/P was obtained with Pyle-Popovich's model, which accounts for both the diffusive (KBD) and convective (sieving coefficient [S]) characteristics of the peritoneal membrane. Garred's model, assuming S = 1, yielded acceptable results for small solutes (except sodium), whereas Henderson's model, in which convective transport is neglected, proved to be surprisingly accurate for KBD for both small solutes (except sodium) and protein. S values (mean +/- SD) calculated using Pyle-Popovich's model were found to be out of the physically interpretable range for glucose (S = -0.38 +/- 0.48) and potassium (S = 1.57 +/- 0.19), and therefore these S values should be treated as phenomenologic rather than physical quantities.
A new balanced operation for complex gastroesophageal reflux disease. Twenty-seven patients with advanced gastroesophageal reflux disease have been treated with combined transthoracic parietal cell vagotomy and Collis-Nissen fundoplication. Gastric acid analyses (n = 20) obtained preoperatively and 6 months postoperatively demonstrated a significant late reduction in gastric acid output. Twenty-six patients (96%) have experienced relief of gastroesophageal reflux disease at a mean of 13.3 months (range, 6 to 25 months) without postvagotomy symptoms. Transthoracic parietal cell vagotomy may be considered as an adjunct to mechanical surgical control of advanced gastroesophageal reflux disease.
A hepatitis B virus mutant associated with an epidemic of fulminant hepatitis BACKGROUND. A nosocomial outbreak of fulminant hepatitis B occurred in five patients in Haifa, Israel. Previous investigations identified the suspected source as a carrier of hepatitis B surface antigen who was positive for antibodies to hepatitis B e antigen and had chronic liver disease. We examined the strain of hepatitis B virus (HBV) that caused this epidemic, in order to identify specific mutations in the precore or core region. METHODS. The presence of HBV was identified by polymerase-chain-reaction amplification of viral DNA in serum from the source patient, the five patients with fulminant hepatitis B, and five controls with acute, self-limited hepatitis B. The amplified viral HBV DNA samples were then cloned and sequenced. RESULTS. Sequence analysis of viral DNA established that the same HBV mutant with two mutations in the precore region was present in the source patient and the five patients with fulminant hepatic failure. This HBV mutant had significant sequence divergence from other known HBV subtypes in the X, precore, and core regions. Cloned HBV DNA derived from a hospitalized patient who had subclinical hepatitis B at the same time as the outbreak and from four other control subjects with acute, self-limited hepatitis B all contained the wild-type sequence in the precore region. CONCLUSIONS. In the outbreak we studied, a mutant hepatitis B viral strain was transmitted from a common source to five patients who subsequently died of fulminant hepatitis B infection. Naturally occurring viral mutations hepatitis B infection. Naturally occurring viral mutations in the HBV genome may predispose the infected host to more severe liver injury.
The neurofibroma in von Recklinghausen neurofibromatosis has a unicellular origin. von Recklinghausen neurofibromatosis (NF1) is the most common hereditary syndrome predisposing to neoplasia. NF1 is an autosomal dominant disease caused by a single gene which maps to chromosome 17q11.2. The most common symptomatic manifestation of NF1 is the benign neurofibroma. Our previous studies of tumors in NF1, studies which detected a loss of heterozygosity for DNA markers from the NF1 region of chromosome 17 in malignant tumors, did not detect a loss in neurofibromas. We report here that a more extensive study, including the analysis of neurofibromas from 19 unrelated NF1 patients by using seven probes, failed to detect a single instance of loss of heterozygosity. This finding suggests that neurofibromas are either polyclonal or monoclonal in origin but arise by a mechanism different from that of NF1 malignancies. In order to investigate the first possibility, we analyzed neurofibromas from female NF1 patients by using an X chromosome-specific probe, from the phosphoglycerokinase (PGK) gene, which detects an RFLP. The detected alleles carry additional recognition sites for the methylation-sensitive enzyme HpaII, so that the allele derived from the active X chromosome is digested by HpaII while the one from the hypermethylated, inactive X chromosome is not. We analyzed neurofibromas from 30 unrelated females with NF1. Eight patients were heterozygous for the PGK RFLP. By this assay, neurofibromas from all eight appeared monoclonal in origin. These results suggest that benign neurofibromas in NF1 arise by a mechanism that is different from that of malignant tumors.
Percutaneous endoscopic jejunostomy in a patient with previous esophagectomy. Establishment of a percutaneous endoscopic jejunostomy via direct jejunal puncture was accomplished in a 45-year-old woman five years after a partial esophagectomy with cervical esophagogastrostomy for adenocarcinoma of the esophagus. The patient had recurrence of the cancer at the anastomotic site with subsequent inability to eat, necessitating a feeding tube for prolonged enteral nutrition. Although percutaneous puncture of the jejunum has been previously described, it has been limited to patients who had undergone partial or complete gastrectomies with Bilroth II anastomoses. This case report of direct endoscopic jejunal tube placement in a patient after esophagectomy further establishes this procedure as a viable alternative to surgically placed feeding tubes in patients with altered gastric anatomy.
A phase I-II trial of induction chemotherapy with carboplatin and fluorouracil in locally advanced head and neck squamous cell carcinoma: a report from the UCL-Oncology Group, Belgium. Eighty-three patients (median age, 56 years and Karnofsky performance status greater than or equal to 70) were treated with carboplatin (Carbo) and fluorouracil (5Fu) for stage III and IV head and neck squamous cell carcinoma (HNSCC). 5Fu (1 g/m2/d) was administered from day 1 to 4 by continuous infusion. Carbo was given on day 1 and, in order to evaluate its maximum-tolerated dose (MTD), the dose level was progressively increased from 250 mg/m2 to 450 mg/m2. The effectiveness of this association and its potential role in local control were also evaluated. Three patients received Carbo at a dose of 250 mg/m2, 13 received 300 mg/m2, one received 330 mg/m2, 12 received 350 mg/m2, six received 375 mg/m2, 26 received 400 mg/m2, 18 received 420 mg/m2, and four received 450 mg/m2. Two (13 of 83) or three courses (64 of 83), repeated every 4 weeks, were administered. The overall (primary tumor and node) response and complete response (CR) rates were 33% and 14%, respectively. For primary tumor, the response rate (RR) was 57% with 32% CR and 18% pathologic complete response (PCR); the RR was higher for patients with oropharyngeal tumor (76%, P = .037) and for patients treated with Carbo greater than or equal to 350 mg/m2 (65%, P = .02); the tumor size (T1 + T2 v T3 + T4) was a good prognostic factor for RR (90% v 46%, P = .001), CR (65% v 20%, P less than .001), and PCR (45% v 8%, P less than .001). For nodes, the RR was 33% with 11% CR. Grade 3-4 neutropenia and thrombocytopenia were experienced by 17% and 28% of the patients treated with 420 mg/m2 of Carbo and by 50% of the patients treated with 450 mg/m2. The MTD can be fixed at 420 mg/m2 and the proposed dose at 400 mg/m2. Thirty-eight patients were treated with surgery plus radiotherapy, 33 with radiotherapy alone, and seven with surgery alone. The median follow-up is 12 months. The 18-month disease-free survival (DFS) is 78% for overall complete responders and 39% for the others (P = .04). There is no primary tumor recurrence among the 12 patients with a primary tumor PCR treated by radiotherapy alone for tumor control (median follow-up, 17.3 months). The association of Carbo-5Fu is a safe induction chemotherapy regimen for HNSCC. The proposed dose of Carbo for future treatment is 400 mg/m2.(ABSTRACT TRUNCATED AT 400 WORDS).
Simplified formula for the calculation of mitral valve area: potential inaccuracies in patients with tachycardia. A simplified formula (cardiac output/[transvalvular pressure gradient]1/2) has been proposed as an alternative to the Gorlin equation for determining valve area in patients with mitral stenosis. This study was done (a) to assess the relationship between the results of the simplified formula and those of the Gorlin equation in patients with mitral stenosis and (b) to determine the clinical characteristics most likely to be associated with a disparity between the 2 formulae. In 96 patients with mitral stenosis, the disparity between the 2 formulae was greater than 0.2 cm2 in 43 (45%) and greater than or equal to 0.35 cm2 in 21 (22%). The results of the simplified formula were especially likely to be disparate from those of the Gorlin equation in those whose heart rates were greater than 100 beats/minute. Thus, in the patient with mitral stenosis, the simplified formula should be used with caution and cognizance of its potential inaccuracy, particularly if the patient is tachycardic.