Vocal function following vertical hemilaryngectomy: comparison of four reconstruction techniques in the canine.

The goals of laryngeal reconstruction have been prevention of aspiration, production of a functional voice, and maintenance of an adequate airway for decannulation. A number of procedures for partial laryngeal reconstruction have accomplished these objectives. However, few studies have attempted to compare patients' vocal characteristics following different reconstruction procedures.

Cost-effective selection of patients for coronary angiography.

In patients suspected of having coronary artery disease (CAD), noninvasive testing has been playing an increasing role in selecting patients who would require coronary angiography for either the "definitive" diagnosis of CAD or as a prelude to planning myocardial revascularization. A mathematic model is presented that defines cost-effective utility of nuclear cardiology testing for diagnosis of CAD and selection of appropriate candidates for coronary angiography, according to quantitative methods of decision analysis. Clinical utility or effectiveness was defined in terms of percent correct diagnosis of CAD.

Kinetics, Ca2+ dependence, and biophysical properties of integrin-mediated mechanical modulation of transmitter release from frog motor nerve terminals.

Neurotransmitter release from frog motor nerve terminals is strongly modulated by change in muscle length. Over the physiological range, there is an approximately 10% increase in spontaneous and evoked release per 1% muscle stretch. Because many muscle fibers do not receive suprathreshold synaptic inputs at rest length, this stretch-induced enhancement of release constitutes a strong peripheral amplifier of the spinal stretch reflex.

The ins and outs of notch signaling.

The Notch gene encodes a cell surface protein that regulates cell fate choices in vertebrates and invertebrates. Given the wide variety of cell types influenced by Notch, it would seem that the signal relayed through Notch activation is not an instructive one per se. Rather, Notch signaling is thought to influence the cell's ability to respond to instructive signals responsible for specific cell fates.

Bronchodilators: new drugs and controversies.

After complete abstinence, regular use of short-acting beta 2-agonists results in an increase in early and late asthmatic (allergen) response, exercise-induced bronchoconstriction, and nonspecific airways responsiveness (methacholine). Regular use of long-acting beta 2-agonists also results in increased nonspecific airways responsiveness (methacholine) with or without concomitant inhaled corticosteroids and attenuates the response to escalating doses of inhaled short-acting beta 2-agonists such as might be used in an acute exacerbation. In spite of these findings, symptom control and bronchodilation are improved more with the addition of salmeterol than with a doubling of inhaled corticosteroid dose.

Sensitivity, specificity, and positive predictive value of technetium 99-HMPAO SPECT in discriminating Alzheimer's disease from other dementias.

Investigators have reported high sensitivity and specificity values for single photon emission computerized tomography (SPECT) when distinguishing Alzheimer's disease (AD) patients from normal elderly controls or from selected patient groups. The role of SPECT in identifying AD among unselected patients with memory complaints requires investigation. We examined 139 consecutive patients with 99Tc-HMPAO SPECT.

A comparison of gene transfer methods in human dendritic cells.

Dendritic cells (DCs) are the most potent antigen-presenting cells (APCs) for the initiation of antigen-specific T-cell activation. DCs may be highly enriched from peripheral blood-adherent leukocytes by short-term (7-day) culture in the presence of interleukin (IL)-4 and granulocyte-macrophage colony-stimulating factor. Various methods of gene transfer were studied, including DNA/liposome complexes, electroporation, CaPO4 precipitation, and recombinant adenovirus (AdV) vectors.

HTLV-1 gene expression in adult T-cell leukemia cells elicits an NK cell response in vitro and correlates with cell rejection in SCID mice.

Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent of adult T-cell leukemia (ATL). We have previously shown that the ATL cell line, RV-ATL, formed tumors when inoculated into severe combined immunodeficient (SCID) mice. In contrast, the HTLV-1 in vitro-transformed cell line, SLB-1, was nontumorigenic in SCID mice.

Immunotherapy and gene therapy.

Currently, there are many options for the treatment of metastatic renal cell carcinoma (RCC). Being a mostly chemoresistant malignancy, renal cell carcinoma is usually treated with immunotherapy. These therapies are generally based on interleukin-2 (IL-2) or interferon alfa (IFN-alpha), or involve more novel techniques such as gene therapy.

Pretransplant panel reactive-antibody screens. Are they truly a marker for poor outcome after cardiac transplantation?

Background: The effect of pretransplant sensitization on outcome after cardiac transplant has been controversial. Sensitization, defined as a positive panel-reactive antibody (PRA) screen in patients awaiting transplant, represents circulating antibodies to a random panel of donor lymphocytes (usually T lymphocytes). The significance of pretransplant circulating antibodies to B lymphocytes has not been reported, and many centers disregard its use.

Longitudinal behavioral and 6-[18F]fluoro-L-DOPA-PET assessment in MPTP-hemiparkinsonian monkeys.

Biochemical and behavioral criteria were established to determine the long-term stability of a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced unilateral striatal dopamine deficiency in the vervet monkey. At time points over a 12-month period, post-MPTP striatal dopamine synthesis capacity was indexed with 6-[18F]fluoro-L-DOPA (FDOPA)-positron emission tomography. For the MPTP-treated subjects (n = 4), an intrasubject FDOPA influx rate constant (Ki) ratio method of right (lesioned) striatum/left (unlesioned) striatum values was used to assess changes in striatal activity.

Detection of simulated lung nodules with computed radiography: effects of nodule size, local optical density, global object thickness, and exposure.

Rationale And Objectives: We quantified differences in the detection of simulated lung nodules on computed radiographs on the basis of variations in nodule size, local contrast, body habitus (global contrast), and exposure.

Methods: A step-wedge phantom was developed to simulate the attenuation ranges of the lung, retrocardiac, and subdiaphragmatic regions of the adult human chest. Additional Lucite wedges were used to simulate two different body thicknesses and to provide variable structural noise.

Free radicals enhance Na+/Ca2+ exchange in ventricular myocytes.

Oxygen-derived free radicals (OFR) have been implicated in the pathogenesis of intracellular Ca2+ overload and the arrhythmias that characterize cardiac reperfusion. These arrhythmias may in large part be due to activation of the pathological transient inward current (ITI). However, the identity of the ITI generated by OFR is uncertain.

Management of upper gastrointestinal bleeding in the patient with chronic liver disease.

This article reviews the management of severe upper gastrointestinal bleeding in the patient with chronic liver diseases. The initial assessment, diagnostic work-up, and treatment options for variceal and nonvariceal bleeding are discussed. The role of diagnostic and therapeutic endoscopy for esophagogastric varices is reviewed with special emphasis on new endoscopic techniques including variceal band ligation and cyanoacrylate injection.

Dobutamine positron emission tomography: absolute quantitation of rest and dobutamine myocardial blood flow and correlation with cardiac work and percent diameter stenosis in patients with and without coronary artery disease.

Objectives: This study sought to measure myocardial blood flow at rest and during dobutamine infusion and to correlate flow with cardiac work and severity of coronary artery disease.

Background: Dobutamine is used with cardiac imaging to induce possible ischemia in patients with known or suspected coronary artery disease. Positron emission tomography permits noninvasive quantitation of myocardial blood flow.

Novel insights into the genetics, biochemistry, and immunocytochemistry of the 30-kilodalton major extracellular protein of Mycobacterium tuberculosis.

The 30/32-kDa complex of major secretory proteins are among the most important and intensively studied proteins of Mycobacterium tuberculosis. The proteins have been demonstrated to be immunoprotective and to play a central role in the physiology of the mycobacterium. In this study, we present a series of novel insights into this key protein complex arising out of a combination of genetic, biochemical, and immunocytochemical analyses.

Angiolymphoid hyperplasia with eosinophilia and vascular tumors of the head and neck.

Purpose: The clinicopathologic distinctions between angiolymphoid hyperplasia with eosinophilia (AHE) and vascular tumors are controversial. Some investigators believe that AHE is a variant of hemangioma, whereas others state that it is an inflammatory phenomenon. To better delineate the clinicopathologic entity of AHE and investigate the efficacy of various treatment regimens, we undertook a retrospective analysis of AHE and compared it with other angiomatous lesions treated at a tertiary referral center.

Generation of complement membrane attack complex in normal human corneas.

Purpose: To determine whether complement-derived SC5b-9, the soluble nonlytic-fluid phase of the membrane attack complex, can be generated in normal human corneas when they are injured with lipopolysaccharide (LPS), ribitol teichoic acid (RTA) immune complexes, acid, or alkali.

Methods: The experimental cornea of each donor pair was injected with 50 microliters of sterile saline containing 0.5 mg of LPS or 50 microliters of sterile saline containing 250 micrograms of RTA immune complexes.

Nodal nevi and cutaneous melanomas.

Nevocytes in melanoma-draining lymph nodes can be mistaken for melanoma metastases and may possibly transform to melanoma. During the development of a new technique for managing high-risk primary melanomas, selective lymph node dissection, we examined 4,821 nodes from 208 melanoma patients by light microscopy and immunohistochemistry. Nodal nevi were identified in 49 of 226 lymphadenectomy specimens (22%), a frequency considerably higher than previously recorded (5-6%).

Posterior segment neovascularization associated with optic nerve aplasia.

Purpose: To report the presence of posterior segment neovascularization in eyes with optic nerve aplasia.

Methods: Three eyes in two patients with clinical optic nerve aplasia were studied.

Results: Examination disclosed posterior segment neovascularization in one eye and progressive posterior segment neovascularization in two eyes.

Carbachol does not correct the defect in the phagocytosis of outer segments by Royal College of Surgeons rat retinal pigment epithelial cells.

Purpose: To investigate the effect of carbachol on the phagocytosis of photoreceptor outer segments (OS) in cultures of normal Long-Evans and dystrophic Royal College of Surgeons (RCS) rat retinal pigment epithelial (RPE) cells.

Methods: Retinal pigment epithelial cells from normal and RCS rats were grown in tissue culture. On reaching confluence, they were presented with OS suspended in Krebs-Henseleit buffer in the presence or absence of carbachol and LiCl.

Two-phase helical CT for pancreatic tumors: pancreatic versus hepatic phase enhancement of tumor, pancreas, and vascular structures.

Purpose: To quantitatively evaluate and validate a two-phase helical computed tomographic (CT) protocol for evaluation of pancreatic tumors.

Materials And Methods: Twenty-seven patients with pathologically proved pancreatic adenocarcinomas prospectively underwent two-phase CT examination with helical acquisition during the pancreatic phase (40-70 seconds after infusion of intravenous contrast material at 3 mL/sec) and the hepatic phase (70-100 seconds after infusion). Mean CT attenuation values of tumor, bordering pancreas, and all major peripancreatic vessels were obtained for both time intervals.

Potassium and chloride currents in rat gastric enterochromaffin-like cells.

The gastric enterochromaffin-like (ECL) cell secretes histamine in response to secretagogues (gastrin, acetylcholine) by calcium signaling-dependent exocytosis of intracellular vacuoles containing the hormone. ECL cells were isolated from rat fundic gastric mucosa by elutriation and density-gradient centrifugation. Currents across the plasma membrane were measured using whole cell patchclamp methods.