Investigating the Impact of Polymer Length, Attachment Site, and Charge on Enzymatic Activity and Stability of Cellulase.

The thermophilic cellulase Cel5a from (Cel5a) was conjugated with neutral, cationic, and anionic polymers of increasing molecular weights. The enzymatic activity toward an anionic soluble cellulose derivative, thermal stability, and functional chemical stability of these bioconjugates were investigated. The results suggest that increasing polymer chain length for polymers compatible with the substrate enhances the positive impact of polymer conjugation on enzymatic activity.

Interleukin 1α Is Critical for Resistance against Highly Virulent Aspergillus fumigatus Isolates.

Heterogeneity among isolates results in unique virulence potential and inflammatory responses. How these isolates drive specific immune responses and how this affects fungally induced lung damage and disease outcome are unresolved. We demonstrate that the highly virulent CEA10 strain is able to rapidly germinate within the immunocompetent lung environment, inducing greater lung damage, vascular leakage, and interleukin 1α (IL-1α) release than the low-virulence Af293 strain, which germinates with a lower frequency in this environment.

False recollection of the role played by an actor in an event.

Two experiments demonstrated that eyewitnesses more frequently associate an actor with the actions of another person when those two people had appeared together in the same event, rather than in different events. This greater likelihood of binding an actor with the actions of another person from the same event was associated with high-confidence recognition judgments and "remember" responses in a remember-know task, suggesting that viewing an actor together with the actions of another person led participants to falsely recollect having seen that actor perform those actions. An analysis of age differences provided evidence that familiarity also contributed to false recognition independently of a false-recollection mechanism.

Sirenomelia: Mermaid deformity on fetal MR imaging.

This case involves the rare congenital disorder Sirenomelia, a diagnosis initially suspected during prenatal ultrasound and later confirmed by prenatal MRI. Sirenomelia, or mermaid syndrome, is mainly characterized by variable fusion of the lower limbs and by genitourinary anomalies. The vast majority of cases of this disease result in death secondary to associated renal agenesis or hypoplasia.

Debriefing medical teams: 12 evidence-based best practices and tips.

Background: Medical teams are commonly called on to perform complex tasks, and when those tasks involve saving the lives of critically injured patients, it is imperative that teams perform optimally. Yet, medical care settings do not always lend themselves to efficient teamwork. The human factors and occupational sciences literatures concerning the optimization of team performance suggest the usefulness of a debriefing process--either for critical incidents or recurring events.

Extracardiac manifestations of infective endocarditis and their historical descriptions.

In his landmark "Gulstonian Lectures on Malignant Endocarditis," published in 1885, William Osler commented, "Few diseases present greater difficulties in the way of diagnosis than malignant endocarditis, difficulties which in many cases are practically insurmountable." At that time, the fields of microbiology and blood cultures were in their infancy, and the diagnosis was made premortem in just half the patients with the condition. After Osler's report, extracardiac physical findings became essential clues to earlier diagnosis.

Why does the heart beat? The discovery of the electrical system of the heart.

Why does the heart beat? This question--known as the myogenic versus neurogenic theory--dominated cardiac research in the 19th century. In 1839, Jan Evangelista Purkinje discovered gelatinous fibers in the ventricular subendocardium that he thought were muscular. Walter Gaskell, in 1886, demonstrated specialized muscle fibers joining the atria and ventricles that caused "block" when cut and found that the sinus venosus was the area of first excitation of the heart.

Woldemar Mobitz and His 1924 classification of second-degree atrioventricular block.

Woldemar Mobitz, an early 20th century German internist, analyzed arrhythmias by graphing the relationship of changing atrial rates and premature beats to AV conduction. Through an astute mathematical approach, he was able to classify second-degree atrioventricular block into 2 types, subsequently referred to as Mobitz type I (Wenckebach) and Mobitz type II (Hay). Type I AV block was most often due to digitalis and was reversible.

Comparison of the prevalence of first-degree atrioventricular block in African-American and in Caucasian patients: an electrocardiographic study III.

Background: Electrocardiographic (ECG) differences occur between African-American and Caucasian patients.

Methods: The study includes ECGs of 2,123 patients, ages 20-99 years attending an urban hospital.

Results: First-degree atrioventricular (AV) block was more prevalent in African-American patients compared with Caucasian patients in all age groups of the study except for those patients in the eighth decade of life.

Lower prevalence of intraventricular block in African-American patients compared with Caucasian patients: an electrocardiographic study II.

Background: Electrocardiographic (ECG) differences occur between African-American and white persons.

Methods: Intraventricular conduction abnormalities of ECGs of 2,123 African-American and white hospital patients ages 20-99 years were studied in a consecutive manner.

Results: Intraventricular conduction abnormalities develop later in life and are less common in African-American patients, compared with white patients.

Walter Gaskell and the understanding of atrioventricular conduction and block.

Walter Holbrook Gaskell was a nineteenth-century British physiologist whose investigations from 1874 until 1889 became central to our current understanding of cardiac physiology. His many cardiac contributions include the following: 1) the recognition of certain inherent properties of cardiac muscle; 2) the experimental proof that led to the acceptance of the myogenic theory of the origin of the heartbeat; 3) the mapping of the anatomy of the sympathetic nervous system; 4) the understanding of the dual autonomic control of the heart; 5) the discovery of the vasodilating effect of sympathetic stimulation on blood flow through skeletal muscle arteries; and 6) the introduction of the concept of heart block. Gaskell's elucidation of the sequence of cardiac contraction and atrioventricular block and his concepts of rhythmicity, excitability, contractility, conductivity and tonicity provided the physiologic explanation necessary for the future understanding of cardiac rhythm disturbances.

Reduced prevalence of atrial fibrillation in black patients compared with white patients attending an urban hospital: an electrocardiographic study.

Electrocardiographic differences occur between African-American and white persons. The cardiac rhythms of 2123 African-American and white hospital patients from 20 through 99 years of age were studied in a consecutive manner. The prevalence of atrial fibrillation increases dramatically with advancing age in both African-American and white patients.

Alfred Lewis Galabin and the first human documentation of atrioventricular block.

Using an apexcardiogram, Galabin was the first person to document atrioventricular (AV) block in humans. He performed his studies while working as a house officer at Guy's Hospital, London, United Kingdom. His patient was 34 years old, experienced attacks of near syncope, and had a pulse rate that varied between 25 and 30 beats/min.

Granzyme B: a marker of risk for influenza in institutionalized older adults.

Risk for influenza increases with age while cellular immune responses decline. This was a prospective study to determine the relationship between cytokine and granzyme B levels in peripheral blood mononuclear cells stimulated with live influenza virus, and subsequent influenza illness. Granzyme B levels were lower in the group who later developed symptomatic laboratory-confirmed influenza (n=10) compared to the group who did not (n=90) (ANOVA, P=0.

Luigi Luciani and the earliest graphic demonstration of Wenckebach periodicity.

Using an isolated frog heart preparation with ligatures around the atria, Luigi Luciani, an Italian physiologist working in 1873 in Carl Ludwig's famous laboratory in Leipzig, was the first to demonstrate cardiac group beating, which he named periodic rhythm. He attributed this to increased resistance to impulse propagation between the atria and the ventricle. Karel F.

The Wenckebach phenomenon: a salute and comment on the centennial of its original description.

In 1899, Karel F. Wenckebach unraveled the complicated arrhythmia that bears his name--one of the most famous eponyms in medicine. He reported his findings before the benefit of clinical electrocardiography or the discovery of the sinoatrial and atrioventricular nodes.

Assessment of markers of the cell-mediated immune response after influenza virus infection in frail older adults.

The purpose of this study was to determine whether measures of the cell-mediated immune response to influenza virus could be used as markers of influenza virus infection. We studied 23 subjects who developed upper respiratory, lower respiratory, or systemic symptoms during a small outbreak of influenza in a nursing home population. Influenza virus culture from nasopharyngeal swabs yielded influenza virus isolates from 7 of the 23 subjects.

Responses to influenza vaccination in different T-cell subsets: a comparison of healthy young and older adults.

T-lymphocyte responses to influenza vaccination were measured in healthy young and older adult volunteers. All participants were vaccinated with the 1995-96 trivalent influenza vaccine. Cytokine and granzyme B levels were measured in peripheral blood mononuclear cells (PBMC) cultures after virus stimulation, prior to and 4 and 12 weeks after vaccination.

Immune response to influenza vaccination in institutionalized elderly: effect on different T-cell subsets.

Humoral and cellular immunological responses to influenza vaccination were measured in volunteers in a long-term care facility. All participants were vaccinated with the commercially available 1994-95 trivalent influenza vaccine and blood samples were collected before and 6 and 12 weeks after vaccination. Cytokine and granzyme B in peripheral blood mononuclear cell (PBMC) cultures after virus stimulation, and serum antibody titres were measured for each of these time points.

Hemodynamic changes after cardioversion of chronic atrial fibrillation.

After cardioversion of chronic atrial fibrillation to sinus rhythm, there is a gradual increase of 56% in cardiac output over 4 weeks. The increase is caused by the gradual return and increasing strength of left atrial mechanical activity as the atrial myopathy of chronic atrial fibrillation subsides. Cardiac output decreases after cardioversion of atrial fibrillation in more than a third of patients, and the decrease may last a week.