The prothrombin time (PT) is frequently performed to monitor anticoagulant therapy. Although relatively simple to perform, it requires venipuncture and laboratory resources for sample handling and ...analysis. A recently developed capillary whole blood device that uses fingerstick samples was evaluated. Paired capillary whole blood and reference plasma PTs were performed in 858 samples from 732 subjects. The PT for normal volunteers (n = 193) was 11.8 +/- 0.9 seconds with the use of the new instrument and 12.1 +/- 0.5 seconds with the use of the reference method. In samples from 539 patients receiving anticoagulants, the correlation coefficient between the two methods was 0.96. Venous whole blood without anticoagulant and capillary whole blood gave equivalent results, which suggests that the fingersticks do not effect the quality of the specimen. Variation in hematocrit between 23.4% (0.34) and 53.8% (0.538) did not alter the performance of the instrument. The new instrument is easy to use and may allow testing by nonlaboratory personnel and patients. It obviates the need for venipuncture, provides immediate results, and appears to be comparable in accuracy to current reference methods.
Myeloperoxidase staining methods for classification of leukemias have traditionally employed benzidine dihydrochloride as the chromogen. Recent Occupational Safety and Health Administration ...regulations have classified benzidine as a carcinogen, which severely restricts its use in the clinical laboratory. Twenty-two specimens from normal control subjects and leukemia patients, previously classified by FAB criteria, were stained with benzidine and two alternate chromogens, diaminobenzidine and Hanker-Yates reagent (p-phenylenediamine and pyrocatechol). In a random, blind fashion, three experienced observers scored the stains from each case according to quality of smear, degree of peroxidase positivity, tinctorial distinction between nucleus and cytoplasm, and overall acceptability of the stain. All three observers rated the substitute chromogens as adequate for routine myeloperoxidase cytochemical staining. It is concluded that either of the methods studied would have clinical utility and can substitute for benzidine as a myeloperoxidase chromogen.
It is crucial to monitor the levels of Non-Ionizing Radiation (NIR) to which the general population may be exposed and compare them to the limits defined in the current standards, in view of the ...rapid rise of communication services and the prospects of a connected society. A high number of people visits shopping malls and since these locations usually have several indoor antennas close to the public, it is therefore a kind of place that must be evaluated. Thus, this work presents measurements of the electric field in a shopping mall located in Natal, Brazil. We proposed a set of six measurement points, following two criteria: places with great the flow of people and the presence of one or more Distributed Antenna System (DAS), co-sited or not with WiFi access points. Results are presented and discussed in terms of the distance to DAS (conditions: near and far) and flow density of people in the mall (scenarios: low and high number of people). The highest peaks of electric field measured were 1.96 and 3.26 V/m, respectively corresponding to 5% and 8% of the limits defined by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the Brazilian National Telecommunication Agency (ANATEL).
We report a new plasminogen disorder detected in a 29-year-old man with a cerebellar infarct. To our knowledge, plasminogen disorders have not been previously linked with stroke.
Tests for ...well-recognized causes of stroke were negative. However, a screening hypercoagulation profile indicated low functional levels of plasminogen activity. Immunologic plasminogen (Laurell technique) was 64% of normal (normal level, 80-130%). The rate of plasmin generation induced by adding urokinase to plasma was also low. Plasminogen activator, free protease, and alpha 2-plasmin inhibitor levels were normal. Family studies detected a similar plasminogen abnormality in the patient's mother and 9-year-old son, both of whom are asymptomatic.
Our patient shows a congenital, heterozygous, functionally abnormal plasminogen. Although the exact relationship to stroke is unclear, we suggest screening young patients with unexplained stroke for plasminogen defects using commercially available assay systems.
The relationship of the reduced glutathione (GSH) content in unstimulated platelets and their capacity to synthesize thromboxane A2 (TXA2), measured by radioimmunoassay of TXB2, was investigated in ...diabetic and matched control subjects. The GSH content in platelets from diabetic subjects (6.52 +/- 0.73 microgram/10(9) platelets, mean +/- SD) was significantly (P less than 0.001) lower than in platelets from control subjects (10.10 +/- 1.58 microgram/10(9) platelets). When platelet-rich plasma (PRP) was stimulated with 1.65 mM arachidonic acid, significantly (P less than 0.001) more TXB2 was formed in PRP from diabetic subjects (344 +/- 87 ng/2.5 X 10(8) platelets) than in PRP from control subjects (132 +/- 35 ng/2.5 X 10(8) platelets). Furthermore, the plasma level of TXB2 was increased in diabetic subjects (522 +/- 117 pg/ml) in comparison with control subjects (187 +/- 63 pg/ml). An inverse correlation (r = 0.98) was observed between the GSH content in unstimulated platelets and their capacity to synthesize TXA2 when stimulated with 1.65 mM arachidonic acid. These data suggest that platelet GSH may have an important regulatory effect on platelet TXA2 synthesis and that increased TXA2 synthesis by platelets from diabetic subjects may be the result of low intracellular GSH levels.
Heterogeneity of Hemin Toalson, L.D.; Lucas, Fred V
Blood,
09/1962, Letnik:
20, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Abstract
A method for the separation of the hemin of hemoglobin into three fractions by ascending paper chromatography is presented. The relative concentration of each fraction of hemin in normal dog ...and human hemoglobin is fairly constant. The relative concentration of the three fractions varies in induced anemia in dogs and in various types of human anemia.
The platelet membrane contains sulfhydryl groups which are essential for normal platelet function. Reduced glutathione (GSH) and other thiols such as cysteine and 6-mercaptopurine were found to ...inhibit human platelet aggregation induced by adenosine diphosphate (ADP), collagen and arachidonic acid. The inhibition of ADP-induced aggregation by GSH (IC50 = 0.61 +/- 0.05 mM) was greater than that by cysteine (IC50 = 13 +/- 1 mM) or 6-mercaptopurine (IC50 = 5.4 +/- 0.2 mM). Two other thiols, dithiothreitol and beta-mercaptoethanol were found to cause platelet aggregation instead of inhibition. The interaction of GSH with the ADP receptor was noncompetitive in nature.
Fifty‐eight patients with clinical inflammatory breast carcinoma and 15 patients with “occult” inflammatory cancer (dermal lymphatic carcinomatosis without clinical inflammation) are grouped and ...reviewed to determine whether diagnosis is pathologic or clinical. All cases represent a retrospective study of records from the Ellis Fischel State Cancer Hospital, Columbia, Missouri. Lesions of clinically apparent and occult inflammatory carcinoma demonstrate similar gross and microscopic growth patterns, histologic types, axillary involvement and early widespread metastases. Regardless of pathologic evidence of dermal lymphatic tumor, patients with clinical inflammation had rapid deterioration. Cases with only a pathological diagnosis were slightly less fulminant in progression. Either clinical or pathologic criteria justify use of the term “inflammatory breast carcinoma” to indicate short‐term prognosis despite available treatment.
Pulmonary vein (PV) isolation for ablation of atrial fibrillation (AF) remains a complex and lengthy procedure.
The purpose of this study was to evaluate the feasibility and safety of a novel ...multielectrode catheter that delivers duty-cycled bipolar and unipolar radiofrequency (RF) energy.
Patients eligible for catheter ablation of paroxysmal AF after screening with magnetic resonance imaging and transesophageal echocardiography were included in the study. A decapolar (3-mm electrode, 3-mm spacing, 25-mm diameter), circular, over-the-wire mapping and ablation catheter was deployed in the antrum of each PV. Ablation was performed with 60-second, 60 degrees C applications of duty-cycled bipolar/unipolar RF in a 4:1 ratio simultaneously at all selected electrode pairs until local activity was no longer observed. At 6 months, 7-day Holter monitoring was performed to determine freedom from AF without use of antiarrhythmic drugs.
In 98 patients (mean age 59 +/- 9 years), the PV ablation catheter was used for ablation of 369 veins (20 common left antra). All targeted veins (100%) were isolated as confirmed by the absence of potentials in the ostium either by PV ablation catheter or Lasso mapping. Mean number of RF applications was 27 +/- 7, total procedural time 84 +/- 29 minutes, and fluoroscopy time 18 +/- 8 minutes. Follow-up after 6 months without antiarrhythmic drugs showed freedom from AF in 83% of patients. No procedure-related complications were observed.
PV isolation by duty-cycled bipolar/unipolar low-power RF energy through a circular, decapolar catheter can be achieved safely and efficiently, with good efficacy at 6 months.
Hybrid forecasting of geopolitical events Benjamin, Daniel M.; Morstatter, Fred; Abbas, Ali E. ...
The AI magazine,
03/2023, Letnik:
44, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Sound decision‐making relies on accurate prediction for tangible outcomes ranging from military conflict to disease outbreaks. To improve crowdsourced forecasting accuracy, we developed SAGE, a ...hybrid forecasting system that combines human and machine generated forecasts. The system provides a platform where users can interact with machine models and thus anchor their judgments on an objective benchmark. The system also aggregates human and machine forecasts weighting both for propinquity and based on assessed skill while adjusting for overconfidence. We present results from the Hybrid Forecasting Competition (HFC)—larger than comparable forecasting tournaments—including 1085 users forecasting 398 real‐world forecasting problems over 8 months. Our main result is that the hybrid system generated more accurate forecasts compared to a human‐only baseline, which had no machine generated predictions. We found that skilled forecasters who had access to machine‐generated forecasts outperformed those who only viewed historical data. We also demonstrated the inclusion of machine‐generated forecasts in our aggregation algorithms improved performance, both in terms of accuracy and scalability. This suggests that hybrid forecasting systems, which potentially require fewer human resources, can be a viable approach for maintaining a competitive level of accuracy over a larger number of forecasting questions.
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