Long-Term Human Immune Reconstitution, T-Cell Development, and Immune Reactivity in Mice Lacking the Murine Major Histocompatibility Complex: Validation with Cellular and Gene Expression Profiles.

Background: Humanized mice transplanted with CD34 hematopoietic cells (HPCs) are broadly used to study human immune responses and infections in vivo and for testing therapies pre-clinically. However, until now, it was not clear whether interactions between the mouse major histocompatibility complexes (MHCs) and/or the human leukocyte antigens (HLAs) were necessary for human T-cell development and immune reactivity.

Methods: We evaluated the long-term (20-week) human hematopoiesis and human T-cell development in NOD Scid Gamma (NSG) mice lacking the expression of MHC class I and II (NSG-DKO).

Abnormal mitral valve motion associated with ventricular septal defect following acute myocardial infarction.

It is often difficult to make the clinical distinction between acute mitral regurgitation caused by papillary muscle dysfunction or rupture and ventricular septal defect complicating an acute myocardial infarction. A case of a patient with rapidly progressive congestive heart failure and a loud murmur is presented. Echocardiography strongly suggested the presence of a flail posterior mitral leaflet.

Systolic time intervals in the syndrome of midsystolic click and late systolic murmur.

Left ventricular function, as measured by systolic time intervals, was studied in 30 subjects with the syndrome of midsystolic click and late systolic murmur (ages, 20 to 53 years; mean, 34 +/- 9 years). Twenty-one were asymptomatic, six had chest pain, two had palpitations, one had shortness of breath, and one had hypotensive episodes. Each patient had the typical auscultatory and echocardiographic findings of the syndrome of midsystolic click and late systolic murmur.

Unusual echocardiographic manifestation of pericardial effusion.

Echocardiographic and sector scanning examinations were performed in a patient with pericardial effusion. In addition to the demonstration of fluid posterior to the left ventricle and anterior to the right ventricle, as in most significant pericardial effusions, there was an echo-free space representing fluid recorded posterior to the left atrium. Several possible explanations of this finding are offered.

Sudden death and the floppy mitral valve syndrome.

A 38-year-old female with a history of palpitations, premature ventricular contractions, and a systolic murmur collapsed suddenly and died. Post-mortem studies showed shortened chordae tendinae and myxomatous transformation of both mitral leaflets. As this syndrome becomes more clinically recognizable it appears that its benignancy is diminishing.

Echocardiographic findings in a patient with Candida endocarditis of the aortic valve.

The echocardiographic appearance of fungal endocarditis of the aortic valve is described in a patient who subsequently died from this disease. In addition, the progressive growth of the vegetation on serial echocardiograms was recorded, and premature closure of the mitral valve was absent, notwithstanding perforation of two aortic cusps.

Neural basis for the genesis and control of digitalis arrhythmias.

The pharmacokinetics of ouabain associated with toxicity were studied in the cat and the guinea pig both in vivo and in vitro using ouabain-H3. After spinal cord transection a higher dose of ouabain was required to reach the lethal endpoint. This intervention also increased the myocardial and serum levels associated with toxicity were studied in the cat and the guinea pig both in vivo and in vitro using ouabain-H3.

Jugular venous pulse recording in a patient without a tricuspid valve.

The unusual contour of the jugular venous pulse tracing (JVPT) in a patient whose tricuspid valve was excised is described. The appearance of an early positive systolic wave (SW) followed by a prominent "V" wave and a delayed deep "Y" descent were noted.

The influence of metiamide on ouabain cardiotoxicity.

The effect of metiamide on the cardiotoxicity produced by ouabain was studied in pentobarbital-anesthetized cats. The onset of ouabain-induced ventricular tachycardia and fibrillation was significantly delayed in cats treated with metiamide as compared with cats that did not receive metiamide. Although the mechanism by which metiamide inhibits ouabain toxicity is speculative, the data suggest that histamine H2-receptor blocking agents may be useful as anti-arrhythmic drugs in digitalis cardiotoxicity.