shukoor65/lab-rag-model huggingface dataset:
Arrhythmogenic effects of graded coronary blood flow reductions superimposed on prior myocardial infarction in dogs. BACKGROUND. We studied arrhythmogenesis and its underlying pathophysiology during graded reductions of coronary blood flow, superimposed on prior myocardial infarction to test the hypothesis that spontaneous ventricular fibrillation and induced ventricular tachycardia are dependent on different patterns of coronary flow reduction in hearts with prior myocardial infarction. METHODS AND RESULTS. In 10 sham-operated dogs (control group) and 24 dogs with 3-week-old experimental apical myocardial infarction, the left circumflex coronary artery was constricted to produce four grades of flow reduction: 25%, 50%, 75%, and 100%. Among the sham-operated control animals, only one of 10 (10%) developed spontaneous ventricular fibrillation and only two of nine (22%) were inducible into sustained ventricular tachycardia during 100% circumflex coronary artery flow reduction. No spontaneous ventricular fibrillation or inducible ventricular tachycardia occurred with lesser grades (25%, 50%, or 75%) of flow reduction among the control animals. In the myocardial infarction group, five of 24 dogs (21%) were inducible before flow reduction. However, 50% flow reduction in the myocardial infarction group resulted in inducibility of ventricular tachycardia in 12 of 24 dogs (50%); nine of 16 (56%) during 75% flow reduction; and six of 11 (55%) with 100% flow reduction. In addition, none of the dogs in the myocardial infarction group developed spontaneous ventricular fibrillation during 25% or 50% flow reduction, whereas six of 22 (27%) developed ventricular fibrillation during 75% flow reduction and 10 of 21 (48%) during 100% flow reduction. In dogs with spontaneous ventricular fibrillation during flow reduction, the total myocardial mass of the ischemic "risk" zone and infarcted zone was significantly greater than in those without spontaneous ventricular fibrillation (68 +/- 5% versus 56 +/- 6% [p less than 0.01]). There was no difference in the total myocardial mass of the ischemic risk zone and infarcted zone between dogs with and without inducible ventricular tachycardia during flow reduction. CONCLUSIONS. In canine model of subacute myocardial infarction, superimposed ischemia increased the likelihood of inducible sustained ventricular tachycardia with lesser grades of coronary flow reduction compared with that necessary to allow spontaneous ventricular fibrillation. The underlying pathophysiology appears to differ between spontaneous ventricular fibrillation and electrically induced sustained ventricular tachycardia.
Liposarcoma of the thyroid gland. Fine-needle aspiration cytology, immunohistology, and ultrastructure. A 56-year-old woman presented with a rapidly growing tumoral mass of the thyroid. In fine-needle aspirates, neoplastic cells were interpreted as undifferentiated (anaplastic) carcinoma. In contrast, histologic examination of tissue samples revealed a tumor with features suggestive of myxoid liposarcoma. The non-epithelial nature was confirmed by immunohistochemical and electron microscopic evaluation. Immunostains for vimentin and S-100 protein were positive, whereas no reactivity was obtained for epithelial markers. Ultrastructurally, the tumor consisted of poorly differentiated mesenchymal cells and lipoblastic elements in various stages of differentiation. Review of the literature reveals only one previous report of thyroid liposarcoma, the diagnosis of which was based on conventional light microscopic studies.
Potent cytodifferentiating agents related to hexamethylenebisacetamide. Bishydroxamic acids are effective inducers of differentiation in murine erythroleukemia cells. Flexible analogs of suberic acid bisdimethylamide are approximately 100 times as active as the parent compound or hexamethylenebisacetamide. They also induce differentiation of human promyelocytic leukemia cells (HL-60) and a subclone of human colon carcinoma cells (HT-29-U4). Some rigid bishydroxamic acids with benzene rings in the spacers are even more active toward murine erythroleukemia cells but show curious biological differences. In contrast to the flexible molecules, those with benzene spacers show poor activity toward HL-60 cells; they also have different geometric requirements, and they are not additive with hexamethylenebisacetamide in their effect. It is likely that rigid bishydroxamic acids, with a benzene ring spacer, induce differentiation by a different mechanism in spite of their chemical resemblance to the flexible bisamide and bishydroxamic acid inducers.
Where there is no anaesthetist.... In an unselected series of 254 operations representing a wide range of surgical, obstetric and gynaecological procedures carried out on the small Pacific island of Tuvalu, the majority (85 per cent) involved the lower half of the body. In all cases but one anaesthesia was administered by a non-specialist. In operations below the level of the diaphragm epidural anaesthesia was usually used with a success rate of 96 per cent. In the upper half of the body ketamine was used where local or regional block was insufficient. Only one operation was performed under general inhalation anaesthesia. The overall postoperative mortality rate was 0.4 per cent and the morbidity rate was 13 per cent. Only two minor complications were attributed to the anaesthetic method used. In situations where anaesthetists are not available, epidural and ketamine anaesthesia in the hands of non-specialists are safe and practical options to general inhalation anaesthesia and are appropriate for most surgical procedures.
Lupus anticoagulant inhibition of in vitro prostacyclin release is associated with a thrombosis-prone subset of patients. PURPOSE: The effect of lupus anticoagulant-containing sera on endothelial prostacyclin generation (both basal and after thrombin stimulation) was determined. Subsets of patients who had experienced arterial, venous, or no thrombosis were compared with respect to the quantitation of antiphospholipid antibody and effects on prostacyclin production. PATIENTS AND METHODS: Serum antiphospholipid antibodies were detected in 26 patients by immunologic (enzyme-linked immunosorbent assay) and kinetic (anticoagulant) assays. Cultured human endothelial cells were exposed to patient or normal serum, and the release of prostacyclin was determined by radioimmunoassay of supernatants. Release was determined in the absence and presence of the secretagogue, thrombin (1 U/mL), corrected for interassay variation, and correlated with other clinical and laboratory variables. RESULTS: The normal prostacyclin response was a 2.5-fold increase after thrombin (1 U/mL) compared to basal production. Patients with a history of arterial thrombosis (Group 1, n = 10) had the highest IgG anticardiolipin antibody titers (449 +/- 115 [OD x 1,000]), most prolonged kaolin clotting times (140 +/- 15 seconds), and the least prostacyclin response to thrombin (1.36-fold). Patients with venous thrombosis (Group 2, n = 6) had lower titers (329 +/- 120), intermediate clotting times (125 +/- 19 seconds), and slightly impaired prostacyclin responses (2.18-fold). Patients with no history of thrombosis (Group 3, n = 10) had low antibody titers (220 +/- 20), mildly prolonged clotting times (108 +/- 6 seconds), and normal prostacyclin responses (2.33-fold). Patient serum did not alter basal or arachidonate-induced prostacyclin production. Group 1 had significantly lower platelet counts (99 +/- 19) compared to Group 2 (167 +/- 35) or Group 3 (167 +/- 34), but were similar in age and associated diagnoses. CONCLUSIONS: Inhibition of prostacyclin responses is commonly found in serum from patients with lupus anticoagulants, and is likely to be present in patients with high IgG anticardiolipin antibodies, strong lupus anticoagulants, low platelet counts, and a recent arterial thrombosis.
Interrelationship between activation of dopaminergic pathways and cerebrospinal fluid concentration of dopamine tetrahydroisoquinoline metabolite salsolinol in humans: preliminary findings. The main objective of this study was to determine whether the activation of dopaminergic pathways, through adrenal-caudate transplantation, stimulated the production of dopamine and salsolinol in cerebrospinal fluid (CSF) of patients with Parkinson's disease. Dopamine sulfate and salsolinol sulfate in CSF specimens were measured by radioenzymatic technique. The results of this study demonstrated that the replacement of degenerative nigrostriatal neurons with new dopamine-producing cells by adrenal brain transplants in patients with Parkinson's disease resulted in significant increase (p less than 0.05) in CSF levels of free dopamine, dopamine sulfate, free salsolinol, and salsolinol sulfate as compared with preoperative levels. Moreover, the oral administration of L-dopa to these transplanted patients caused substantial (p less than 0.001) elevation in CSF levels of free dopamine (before L-dopa, 146 +/- 57 pg/ml; after L-dopa, 575 +/- 207 pg/ml), dopamine sulfate (before L-dopa, 1966 +/- 945 pg/ml; after L-dopa, 41679 +/- 29326 pg/ml), free salsolinol (before L-dopa, 43 +/- 29 pg/ml; after L-dopa, 186 +/- 90 pg/ml), and salsolinol sulfate (before L-dopa, 405 +/- 477 pg/ml; after L-dopa, 2908 +/- 2572 pg/ml), respectively.
Use of mammography in screening for breast cancer. Recognizing the enormous impact that quality breast screening mammography can have on reducing breast cancer deaths, we need to determine when women's and physician's perceived restrictions for mammography examination impede the progress of its use for early cancer detection. A uniform system should emphasize valid communication and education between women and their physicians. Women seek to have a voice in their medical treatment. Yet that responsibility has an emotional price. Physicians and patients must decide together on the most appropriate strategies to enhance communication and adopt specific guidelines they will adhere to, to detect and cure early breast cancer. Women must be educated about breast screening mammography, and physicians must increase their efforts to proclaim its importance. Women need be assured the trend is toward using the most modern mammographic techniques. Quality medical care is medicine's purpose and in women's best interest. At present, no other diagnostic method is equivalent to mammography and capable of providing an equivalent impact on improving the detection and cure rate of breast cancer. Despite medical activities designed to reduce uncertainty in medicine, scientific evidence has not provided systematic answers as to the "best" way to approach issues of quality, cost, accessibility, or communication for breast screening mammography. No particular expert opinion or preference prevails for breast screening protocols. What is needed is adoption of a multidisciplinary approach, educating and motivating women and physicians to participate in breast screening activities. With trends directed toward high-volume breast screening operations, low-cost, quality mammography must be available and be impeccably performed. Some activities are natural subjects for financial quantification. It is objectionable to assume, however, that we can accurately place and agree on dollar amounts alone to represent the costs and benefits of screening mammography. The gaps between practices and attitudes about the benefits, risks, and costs of screening mammography suggest that people are not satisfied with the way physicians, women, influential groups, or regulatory agencies are balancing all of the elements. Better communication must exist between physicians and their peer groups involved in performing responsible mammography. Better communication must be achieved between physicians and women to take advantage of the usefulness of quality breast screening mammography. High-quality screening programs must be linked to third-party reimbursement and to legislation, if we are to make a difference. Screening mammography deserves our medical, economic, social, and political attention and action.
Cerebellorubral degeneration after resection of cerebellar dentate nucleus neoplasms: evaluation with MR imaging. The authors describe the magnetic resonance (MR) findings in seven patients who developed severe cerebellar symptoms and atrophy of the contralateral red nucleus following removal of unilateral neoplasms in the deep nuclei of the cerebellum. For most patients, pre- and postoperative spin-echo MR images were obtained with long repetition times (TRs) at 1.5 T. The long TR images obtained before surgery demonstrated unilateral masses involving the dentate nucleus. Long TR images obtained after surgical resection of the dentate nucleus showed increased signal intensity in all of seven contralateral red nuclei, three of seven ipsilateral superior cerebellar peduncles, and two of seven contralateral inferior olivary nuclei. Three other patients who underwent surgery for cerebellar neoplasms without resection of the dentate nuclei showed no postoperative brain stem changes on MR images. The authors speculate that the changes in the contralateral red nuclei are due to cerebellorubral degeneration (since well-described neural tracts interconnect the dentate nucleus and the contralateral red nucleus). Injury of the dentate nucleus may result in degeneration of distant neural connections.
N-terminal pro atrial natriuretic peptide in human plasma. N-Terminal pro ANP (atrial natriuretic peptide) in human plasma has been measured by radioimmunoassay after extraction on Sep-Pak cartridges. Immunoreactive N-terminal pro ANP circulates in human plasma at higher levels than alpha-hANP (approximately 20-fold higher in normal subjects) and was elevated in patients with essential hypertension, cardiac transplantation and patients with chronic renal failure. In chronic renal failure patients undergoing hemodialysis, C-terminal ANP (ANP 99-126), but not N-terminal ANP, declined significantly after dialysis. Gel filtration experiments demonstrated a single peak of N-terminal ANP immunoreactivity, eluting in parallel with synthetic human pro ANP 1-67, indicating a similar molecular size and the absence of low molecular weight N-terminal fragments.
Activity of intrapleural recombinant gamma-interferon in malignant mesothelioma. Twenty-two consecutive patients with malignant diffuse pleural mesothelioma were treated with recombinant gamma-interferon by the intrapleural route. Diagnosis was made by thoracoscopic examination and all cases were confirmed by the French Mesothelioma Panel of Pathologist. Patients were staged based on thoracoscopic examination and computed tomography (CT) scan: 12 patients were classified as Stage I and 10 were Stage II. A solution of gamma-interferon (40 X 106 U) was infused twice a week over 2 months. Every patient experienced fever. One patient had a Grade 2 leukopenia and one patient suffered from pleural empyema. Response evaluation was based on the following: (1) CT scan performed 2 weeks after treatment ended, and (2) repeat thoracoscopic examination with histopathologic verification in nine patients who had demonstrated a stabilization or a regression of the disease on CT scan. From the original group, 19 patients could be evaluated. Four complete thoracoscopic histopathologic responses and one partial response were observed in Stage I patients (56%). One partial response was observed in Stage II patients.
Hyperreninemic hypoaldosteronism due to hepatocellular carcinoma metastatic to the adrenal gland. Metastases to the adrenal glands are common in patients with cancer, but among those affected, hyperreninemic hypoaldosteronism is noted very rarely. A case of hyperreninemic hypoaldosteronism secondary to metastatic hepatocellular carcinoma is reported. Laboratory data revealed selective aldosterone deficiency with hyperreninemia. Biopsy documented replacement of the adrenal glands with metastatic hepatocellular carcinoma. A review of the literature disclosed that the present case was an extremely rare one of its kind.
Controlling gastric pH: the impact of newer agents on the critically ill patient. The critically ill patient is at increased risk for developing erosive injury of the stomach, duodenum, and esophagus. To date, the most effective way to prevent and treat this problem is by assuring excellent intensive care support and by reducing gastric acid secretion. The histamine H2-receptor antagonists (H2RAs) are effective in both prevention and treatment of such gastric mucosal injury. Newer agents are available that have potential for use in this setting, although none have been studied as extensively in critically ill patients as have the H2RAs. These new agents include proglumide, pirenzepine, misoprostol, omeprazole, and somatostatin. To date, only the latter has been extensively studied in critically ill patients. Omeprazole, which suppresses acid very effectively, may be problematic in the critically ill, limited by its oral dosage form, acid-labile properties, and potential drug interactions.
Effect of irreversible dermal necrosis on phagocytic activity of reticuloendothelial system. A model of full-thickness dermal necrosis was produced in rats by the application of liquid nitrogen to a 20% total body surface area of the dorsal skin surface. In this model there was an alteration of reticuloendothelial system phagocytic activity of the lung and spleen as measured by the uptake of technetium 99m-labeled sulfur colloid in vivo. The present results suggest that marked alterations in reticuloendothelial system phagocytic activity can be produced by full-thickness dermal necrosis in the absence of heat.
Iodine 131 metaiodobenzylguanidine scintigraphy of medullary carcinoma of the thyroid [published erratum appears in South Med J 1991 Jul;84(7):816, 937] We have presented a case of sporadic medullary carcinoma of the thyroid with documentation of localization of tracer 131I-MIBG within the primary neoplasm. A review of the nuclear medicine literature of localization techniques for MCT demonstrates that 131I-MIBG, while an excellent choice for diagnosis of pheochromocytoma and neuroblastoma, produces low yield and unpredictable concentration in other neural crest apudomas, including MCT. A low incidence of true-positive results with 131I-MIBG uptake and a high incidence of false-negative results make this radiopharmaceutical a suboptimal choice for diagnostic studies, but a potentially promising one as a therapeutic agent.
Treatment of idiopathic nephrotic syndrome with cyclosporin A in children. Cyclosporin A (CyA, Sandimmun) was given to 71 children with idiopathic nephrotic syndrome, 45 of whom were steroid-dependent with signs of steroid toxicity, and 23 who were steroid-resistant. Cyclosporin A was effective in 80% of the steroid-dependent patients, allowing cessation of corticosteroid treatment. However, most of these patients relapsed when CyA was tapered or withdrawn. In these patients, CyA may be required for long periods of time. Conversely, CyA was less effective in steroid-resistant patients; only 7% achieved remission with CyA alone. Cyclosporin A in association with prednisone may be an effective alternative as 8 out of 14 patients entered remission with this treatment combination. Serial renal biopsies were performed in 43 patients to evaluate the potential nephrotoxicity of the treatment. Eighteen patients developed significant tubulointerstitial lesions which were attributable to CyA nephrotoxicity. The risk of developing chronic nephrotoxicity appears to be higher in steroid-resistant patients, and was not related to the duration of treatment. Cyclosporin A nephrotoxicity can develop in patients with normal renal function.
Calcium metabolism in hypertension and allied metabolic disorders. Data suggest a critical role for Ca metabolism in the pathophysiology of hypertensive disease. Intracellularly, all hypertension displays elevated cytosolic free-Ca2+ and suppressed free-Mg2+ levels. Extracellularly, however, heterogeneous defects in Ca and Mg metabolism are observed. This apparent divergence may be explained by considering all hypertension as the expression, in varying degrees, of two underlying Ca-related mechanisms: one (salt sensitive, low renin, Ca(2+)-antagonist sensitive) dependent on inappropriate cellular Ca2+ uptake from the extracellular space and the other (salt insensitive, renin dependent, Ca(2+)-antagonist insensitive) dependent on increased cellular Ca2+ release from intracellular sites. Recent work highlights the role of 1,25-dihydroxyvitamin D3 and the newly described parathyroid hypertensive factor in volume-dependent low-renin forms of hypertension. Altered cellular ion handling may also explain metabolic and clinical correlates of hypertension, e.g., peripheral insulin resistance, hyperinsulinemia, obesity, and non-insulin-dependent diabetes mellitus (NIDDM). Thus, all subjects with NIDDM, whether hypertensive or not, display the same elevated cytosolic free-Ca2+ and suppressed free-Mg2+ levels observed in hypertension. Furthermore, adiposity, the level of blood pressure, and fasting and postglucose hyperinsulinemia are all closely and quantitatively related to intracellular free-Ca2+, free-Mg2+, and pH levels. This suggests a broader hypothesis, in which hypertension, obesity, insulin resistance, and NIDDM, each usually considered a distinct clinical entity, represent different clinical expressions of a common defect in cellular ion handling, hence explaining their frequent clinical coexistence in the general population.
Model for studying virus attachment. II. Binding of biotinylated human T cell leukemia virus type I to human blood mononuclear cells potential targets for human T cell leukemia virus type I infection. Purified human T cell leukemia virus type I (HTLV-I) was biotinylated and used to study its attachment to human PBMC. The use of biotinylated HTLV-I (biot-HTLV-I) in conjunction with mouse mAb specific for selected cell-surface molecules and flow cytometric analysis allowed us to positively identify virus-binding cells among a heterogeneous blood mononuclear cell population. Biot-HTLV-I efficiently bound not only to T cells, but also to B cells and monocytes. Preincubation of monocytes with excess of unlabeled HTLV-I significantly reduced the attachment of biot-HTLV-I. HTLV-I not only bound to, but also infected, B cells, as suggested by: i) in situ hybridization of a 35S-labeled full length HTLV-I DNA probe with EBV-transformed B cells, previously cocultured with HTLV-I-producing (G11MJ) T cells, and ii) hybridization of the same nick-translated 32P-labeled DNA probe with blotted DNA from similar HTLV-I-infected EBV-transformed B cells. HTLV-I infection did not affect the ability of B cells to secrete IgG. These findings suggest that HTLV-I cannot only infect cells of the T lineage, but can also infect B cells.
In vivo thrombus formation on a guidewire during intravascular ultrasound imaging: evidence for inadequate heparinization. We present a case in which thrombus formation on a guidewire was visualized during intravascular ultrasound imaging despite the administration of 10,000 units of heparin sulfate prior to the procedure. Gross thrombus formation was confirmed upon removal of the guidewire. The activated clotting time was found to be 191 s, suggesting heparin resistance. This report graphically illustrates the potential thrombogenicity associated with intravascular guidewire manipulation during procedures such as intravascular ultrasound imaging and percutaneous transluminal coronary angioplasty. Moreover, this case suggests that adequate heparinization should be routinely verified by measuring the activated clotting time prior to introducing a guidewire into the arterial system.