Portugal's contribution to navigation and discovery of the New World

Even before the birth of Prince Henry the Navigator (1394) Portugal had displayed a maritime calling due to its 500-mile shore line and numerous natural bays. Inspired by the riches of India he saw during the Portuguese exploration along the coast of West Africa, Prince Henry set out methodically to collect information by bringing together Jews and Moors with geographical knowledge to found his School of Navigation. From 1415 until his death in 1460 he attracted to his school the foremost contemporary scholars in mathematics, astronomy, and cartography along with experts in knowledge of the compass, astrolabe, water currents, and the winds. This concentration of talent yielded the invention of the caravel, the most important navigational advancement of the time, crucial for long voyages across the high seas. Although the rest of Europe busied itself in political and religious wars, for 70 years (1415-1492) Portugal alone pursued the discovery of the Atlantic. "No nation in the 15th century exhibited so great a spirit of maritime enterprise as the Portuguese."     

Treatment of acute lymphoblastic leukemia. 30 years' experience at St. Jude Children's Research Hospital

BACKGROUND: Therapy for childhood lymphoblastic leukemia has evolved during the past three decades, but key questions about what are the least toxic, most effective forms of treatment remain unanswered because of the lack of comprehensive follow-up information. METHODS: To assess long-term outcome in the series of clinical trials conducted at St. Jude Hospital, we compared the results of treatment typical of four eras: exploratory combination chemotherapy (era 1, 1962 to 1966; 91 patients), regimens for the control of meningeal leukemia (era 2, 1967 to 1979; 825 patients), limited intensification of therapy (era 3, 1979 to 1983; 428 patients), and extended intensification of therapy (era 4, 1984 to 1988; 358 patients). ("Intensification" refers to strategies of systemic chemotherapy that are more aggressive than conventional ones.) The major end points were survival and event-free survival; we also calculated the relative risk of treatment failure and the rate of relapse or death after treatment ended (post-treatment failure rate). RESULTS: The probability of event-free survival improved significantly in each successive era (P < 0.001 by the log-rank test), reaching 71 percent in era 4. There was a decrease of approximately 50 percent in the risk of treatment failure from one era to the next in each subgroup of patients defined according to different combinations of the leukocyte count, race, age, and sex. Leukemia appeared to be eradicated in patients who remained in complete remission for three years or more after treatment in era 4. The incidence of death due to nonleukemic causes remained 4 to 6 percent despite the trend toward more intensive treatment. An estimated 765 patients (45 percent) are long-term survivors; most of them (80 percent) have no health problems related to leukemia or its treatment. CONCLUSIONS: The development and successful application of preventive therapy for meningeal leukemia, followed by the intensification of systemic chemotherapy, has progressively improved the rate of cure of childhood lymphoblastic leukemia, with relatively few adverse sequelae.     

Reliability of seizure classification using a semistructured interview

Methods for standardized classification of epileptic seizures are important for both clinical practice and epidemiologic research. In this study, we developed a strategy for standardized classification using a semistructured telephone interview and operational diagnostic criteria. We interviewed 1,957 adults with epilepsy ascertained from voluntary organizations. To confirm and expand the seizure history, we also interviewed a first-degree relative for 67% of subjects and obtained medical records for 59%. Three lay reviewers used all available information to classify seizures. To assess reliability, each reviewer classified a sample of subjects assigned to the others. In addition, an expert physician classified a sample of subjects assigned to two of the reviewers. Agreement was "moderate-substantial" for generalized-onset seizures, both for the comparisons between pairs of lay reviewers and for the neurologist versus lay reviewers. Agreement was "substantial-almost perfect" for partial-onset seizures, both for pairs of lay reviewers and for the neurologist versus lay reviewers. These results suggest that seizures can be reliably classified by lay reviewers, using operational criteria applied to symptoms ascertained in a semistructured telephone interview.     

Computer simulation of the precordial QRS complex: effects of simulated changes in ventricular wall thickness and volume

Over a 4-year period 40,923 operations and 44,716 surgical admissions were monitored for both community and hospital onset infections. One thousand eight hundred sixty-five patients had 1966 surgical wound infections and 2056 remote infections including 1652 hospital onset and 404 community onset infections. One thousand one hudnred forty-four patients with multiple infections averaged 40 days in the hospital contrasted with 24 days for 721 patients with a single wound infection. The total excess cost of hospitalization for these patients was $951,150. A statistically significant reduction occurred for urinary tract infections, lower respiratory infections and clean and contaminated surgical wound infections. It is suggested that these are all inter-related and a significant reduction in surgical wound infections can be achieved through control of infections at remote sites, particularly those associated with medical devices. The coagulase positive staphylococcus is still the most important single bacterial species in the primary etiology of surgical wound infections. When the gastrointestinal tract is entered or "supra" infecting organisms appear, gram negative bacteria and mixed gram negative and gram positive infections are dominant. Reduction in remote site infections occurring in surgical patients is necessary to reduce the incidence of surgical wound infections, suggest preventive and control measures, and document the effectiveness of such measures.     

Pressure sensor performance and reliability

Pressure sensor devices are used to monitor the performance characteristics of various systems within the appliance industry. The household washing machine has long employed sensor devices to monitor and control the tub water level during fill cycles. These devices have evolved from early watertight or float switches to rubber diaphragm mechanical-type devices. The development of epoxy packaging capability for silicon sensors, improved die bonding material, and reliability testing results indicate that the silicon piezo-resistive transducer (PRT) promises to be the next plateau. Silicon PRT electronic devices offer a significant size and weight reduction over these mechanical devices. The authors discuss the reliability testing considerations for the sensors and reliability testing for the appliance industry     

Preload assessment in patients with an open abdomen

Health care providers and purchasers of health services have an opportunity to improve patient care and potentially save costs through the wise purchase of interactive health communication applications for patients and employees. Purchasing decisions based on evaluation and evidence should drive the design and development of new systems. The cycle of evaluation includes a needs assessment before system development, usability testing during development, and studies of use and outcomes in natural settings. This type of evidence is critical to our understanding of how best to provide health information and decision assistance to patients, employees, and others.     

Lack of TEL/AML1 fusion in pediatric AML: further evidence for lineage specificity of TEL/AML1

The percutaneous cardiopulmonary support system (PCPS) was used in a 64-year-old woman with cardiogenic shock due to sustained ventricular fibrillation (Vf) caused by severe aortic stenosis and regurgitation. The Vf attack was resistant to cardioversion and adrenaline for lack of left ventricular support by PCPS. She was transported to the operation theater with PCPS in situ and emergency aortic valve replacement was performed. Although preoperative cardiac resuscitation time was long (35 minutes), she was discharged from the hospital on foot without any neurological complications on 84th postoperative day. Because PCPS does not decrease left ventricular systolic stress in poorly contracting dilated heart, early surgical treatment is needed in patients with severely damaged heart.