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Biomedical subjects

L Benson

Publications and source records attributed to L Benson.

At least 37 records · Page 2Linked to original sources
PubMed1999

Testing the Compatibility Test: How Instructions, Accountability, and Anticipated Regret Affect Prechoice Screening of Options.

Subjects screened a set of jobs, retaining those for which they wished to apply and rejecting those that were no longer under consideration. In Experiment 1, subjects who indicated the jobs for which they would apply/not apply screened out fewer jobs than those with instructions to reject/not reject or those with instructions simply to screen (control). There were no differences between the reject and control conditions. Experiment 2 used a design similar to that of Experiment 1, but subjects were made accountable for their screening judgments. The reject-apply discrepancy remained, but the accountability manipulation made the subjects more stringent in their screening compared to those who were not accountable for their judgments. In Experiment 3, subjects were told to consider either the regret resulting from retaining a bad option (regret bad) or the regret from rejecting a good option (regret good). Subjects in the regret bad condition rejected more jobs than did subjects in the regret good condition, but not more than subjects in the control condition. As predicted by image theory, the normal screening process appears to be to screen out the bad options rather than screen in the good options. This is demonstrated by screening in the control condition being similar to screening under the reject instructions (Experiment 1) and under regret bad instructions (Experiment 3), since these conditions were shown to focus attention on the bad options. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Extended aortic root replacement with aortic allografts or pulmonary autografts in children.

OBJECTIVES: To evaluate the early results and effectiveness of left ventricular outflow tract enlargement with aortic allograft or pulmonary autograft in children with complex left ventricular outflow tract obstruction. METHOD: The records of 30 children who underwent aortic root enlargement and replacement with either an aortic allograft (22 patients) or pulmonary autograft (8 patients) between January 1987 and June 1997 were reviewed. The predominant diagnosis was complex left ventricular outflow tract obstruction (n = 19), associated with aortic incompetence in 11 children. Before root enlargement, 27 children underwent surgical valvotomy (14 patients), balloon dilatation (10 patients), or both interventions (3 patients). Mean age at root enlargement was 5.4 +/- 3.5 years (range, 2 days-16 years). Most of the children (27 patients) underwent a Konno aortoventriculoplasty. Concomitant septal myectomy was performed in 4 children, mitral valve procedure in 5 children, and endocardial fibroelastosis resection in 1 child. RESULTS: Five children (17%) died in hospital. Four of these were infants less than 2 months old. All had acute aortic incompetence as the result of recent intervention necessitating urgent operation. The fifth child, aged 10 years, died of myocardial failure 2 weeks after the operation. During the follow-up period (mean length, 4.1 +/- 2.8 years), sudden death occurred in 1 child 3 months after the operation. Follow-up echocardiograms (obtained for 23 of the surviving 24 children within 3 +/- 2.3 years) showed a left ventricular outflow tract gradient reduced from a mean of 65 to 11 mm Hg (P =.001); Z value increased from a mean of -0.5 to 4.1 (P <. 001), and aortic incompetence was trivial or mild except in 2 children. CONCLUSION: Urgent aortic root enlargement in decompensating neonates carries higher mortality rates. In older children, the early results of root enlargement and implantation of allograft or autograft are good.

Adolescent↗
PubMed1998

A Rejection Threshold in Justice Evaluations: Effects on Judgment and Decision-Making.

This research examined the process through which justice evaluations are formed. Using image theory's screening process we hypothesized that a rejection threshold exists with regard to violations of just treatment (e.g., laying off an employee without notice). If the number of violations exceeds the decision-maker's threshold, a negative justice evaluation results. Nonviolations (e.g., providing laid-off employees with a generous severance package) were hypothesized to only influence justice evaluations when violations do not exceed the threshold. Three studies compared the impact of justice violations and nonviolations on fairness evaluations. We also examined differences in fairness evaluations operationalized as judgments vs decisions. Results indicated that when making judgments about fairness, both violations and nonviolations are equally important. However, when one has to decide on a course of action based on considerations of fairness, nonviolations are only considered if fewer than three violations have been encountered. These results identify important distinctions between judgment and decisions and have implication for research examining outcomes of justice evaluations. Copyright 1998 Academic Press.

Journal Article↗
PubMed1998

Hypersensitivity myocarditis caused by an allergic reaction to cefaclor.

An adolescent girl was seen with acute heart failure 6 days after the onset of a viral illness and otitis media treated with cefaclor. An endomyocardial biopsy specimen revealed active myocarditis with an eosinophilic infiltrate typical of hypersensitivity myocarditis. The patient showed dramatic improvement within 48 hours after withdrawal of the drug and administration of corticosteroids and immunoglobulin.

Biopsy↗
PubMed1998

Low temperature aqueous electrospray ionization mass spectrometry of noncovalent complexes.

In the present study we describe conditions that permit the characterization of noncovalent protein-substrate complexes in aqueous solution by microspray electrospray ionization-mass spectrometry (ESI-MS), using a heated transfer capillary at low temperature (45 degrees C). Specifically, we examined the binding of calmodulin to two polypeptides; the calmodulin-binding domain of calmodulin-dependent protein kinase II (CamK-II) and melittin. Calmodulin, a well known calcium-binding protein, binds to a number of small amphipathic peptides in a calcium-dependent manner. Our results directly show that both peptides form equimolar complexes with calmodulin only in the presence of calcium. The stoichiometry necessary for the formation of each complex was 1:1:4 for calmodulin:peptide (melittin or CamK-II):Ca2+, respectively. Furthermore, it is demonstrated that the detection of the complex in ESI-MS is source temperature dependent.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1997

Balloon angioplasty of recurrent coarctation: a 12-year review.

OBJECTIVES: This study was undertaken to investigate the long-term outcome of balloon angioplasty for recurrent coarctation of the aorta in a large series of patients. BACKGROUND: Balloon angioplasty has become the standard treatment for residual or recurrent aortic coarctation. Despite the widespread use of this treatment modality, there are few data outlining the long-term outcome of a large patient cohort. METHODS: Clinical, echocardiographic, hemodynamic and angiographic data on 90 consecutive patients who underwent balloon angioplasty between January 1984 and January 1996 were reviewed. RESULTS: Mean systolic pressure gradients were reduced from 31 +/- 21 to 8 +/- 9 mm Hg after dilation (p = 0.0001). The mean diameter of the stenotic site, measured in the frontal and lateral views, increased by 38% and 35%, respectively (p = 0.001). Neurologic events occurred in two patients, with one death. An aortic tear occurred in one patient, requiring surgical intervention. Optimal results were defined as a postprocedure gradient < 20 mm Hg and were obtained acutely in 88% of patients. At long-term follow-up (12 years), 53 (72%) of 74 patients with an early optimal result remained free from reintervention. Transverse arch hypoplasia, defined as an arch dimension < 2 SD below the mean for age, was the primary predictor of the need for reintervention. CONCLUSIONS: Although the majority of patients undergoing percutaneous balloon angioplasty for recoarctation of the aorta will achieve long-term benefit, the need for further surgical intervention in those with transverse arch hypoplasia remains high.

Adolescent↗
PubMed1997

A phase I trial and pharmacokinetic evaluation of CI-980 in patients with advanced solid tumors.

CI-980 is a synthetic mitotic inhibitor that binds to the colchicine binding site of tubulin. It demonstrates broad activity against human and murine tumor models and shows no cross resistance with tumor models whose mechanism of resistance is mediated by P-glycoprotein (MDR-1). A phase I study was completed in 25 patients with solid tumors using a 24-hour infusion schedule, with courses repeated every 3 weeks. Eight dose levels were tested between 1.2 and 15.6 mg/m2. The maximum tolerated dose was 14.4 mg/m2. Neutropenia was dose-related but not dose-limiting; thrombocytopenia was infrequent. CNS toxicities were dose-limiting and consisted of dizziness, headache, loss of coordination, loss of consciousness, nervousness, and other symptoms. These events occurred near the end of the infusion and were reversible, usually within 24 hours. One patient who was to be treated at dose level 8 (intended dose was 19.2 mg/m2; actual dose was 15.6 mg/m2) became encephalopathic prior to completion of the infusion. Other adverse events included gastrointestinal toxicities (nausea, vomiting, anorexia, constipation, stomatitis, dyspepsia, bleeding, cheilitis), IV site erythema, fever, and fatigue. A partial response was observed in one patient with colon cancer and reductions in CA-125 levels were observed in 2 patients with ovarian cancer. Pharmacokinetics were linear and dose-proportional. Results indicate high systemic clearance and wide tissue distribution. Mean pharmacokinetic parameter values: T1/2 = 5.52 hours, plasma clearance 1163 mL/min/m2, and Vdss 376 L/m2.

Adult↗
PubMed1997

Complication of ventricular demand pacing after orthotopic heart transplantation: unusual case of pacemaker syndrome in an infant.

BACKGROUND: Sinus node dysfunction is the most common indication for antibradycardiac permanent pacing after heart transplantation. Lack of atrioventricular synchrony during pacing can result in symptoms ranging from mild chest discomfort to severe manifestations such as dyspnea, hypotension, and cardiovascular collapse, all of which are ascribed to pacemaker syndrome. In infants pacemaker syndrome is often only recognized in the face of marked hemodynamic compromise. RESULTS: This report details an unusual account of pacemaker syndrome in an infant after orthotopic heart transplantation. CONCLUSIONS: Careful assessment of atrioventricular synchrony is important after infant transplantation.

Angina Pectoris↗
PubMed1996

An additional mitochondrial tRNA(Ile) point mutation (A-to-G at nucleotide 4295) causing hypertrophic cardiomyopathy.

A third point mutation in the mitochondrial tRNA(Ile) gene associated with hypertrophic cardiomyopathy and respiratory chain dysfunction in heart is reported. An A-to-G transition at nucleotide position 4295 was shown to be highly evolutionarily conserved, never present in control individuals, and to segregate with the disease. A PCR-based diagnostic test and endomyocardial biopsies were used to detect both the biochemical deficiency and the level of heteroplasmy in heart. The implications of this new mitochondrial DNA point mutation are discussed.

Adenine↗
PubMed1996

Natural history of Alström syndrome in early childhood: onset with dilated cardiomyopathy.

Alström syndrome is an autosomal recessive disorder characterized by cone-rod dystrophy, obesity, hearing impairment, and diabetes caused by insulin resistance. By reviewing the charts of eight patients followed for periods of 2 to 22 years, we established the natural history of this syndrome during childhood. Five patients, in four families, were seen between the ages of 3 weeks and 4 months with a dilated cardiomyopathy, a previously unrecognized feature of the syndrome. Photophobia and nystagmus were first documented in the eight patients between the ages of 5 months and 15 months. In all patients, electroretinography initially showed a severe cone impairment with mild (2/8) or no (6/8) rod involvement. Electroretinograms, obtained again at ages 9 to 22 years for four patients, revealed extinguished rod-and-cone responses. Obesity developed during childhood in seven patients, in at least three of them before age 2 years. Hearing impairment (5/8) and diabetes/glucose intolerance (4/8) were diagnosed at the end of the first decade or during the second decade. This constellation of features should facilitate early diagnosis of the syndrome.

Adolescent↗
PubMed1996

HMO partnering: the provider dilemma.

While the growth of HMOs has slowed patient visits to doctors, it also has created a deluge of press clippings. On July 16, 1996, three articles on the subject appeared in the Wall Street Journal, front section. The headlines painted a vivid picture of the forces acting on HMOs and providers alike (Figure 1). The articles portended more change for healthcare. The "shake-out," a term applied to industries in serious transformation, brings shedding of excess capacity and loss of jobs and income. Providers, in particular, find themselves in a difficult dilemma. They must not only cut costs as reimbursement drops, but also retain patients with good outcomes and high quality service. Patient retention means keeping the individual patient from switching to another provider and keeping the insurer's group of patients as an authorized provider for that insurer. The relationship between provider and HMO lies at the heart of the provider dilemma. The HMO structure, which shifts financial risk for care, is quickly setting the standard, for healthcare pricing, medical standards, and management practices. Understanding and responding to HMO needs are vital to competitive advantage and survival. The article discusses the inherent dilemma of HMO and provider partnering and suggests provider responses.

Accounting↗
PubMed1994

Cardiac dysfunction late after cardiotoxic therapy for childhood cancer.

Despite a wealth of data documenting acute cardiac injury from anthracycline therapy and/or mediastinal radiotherapy used for childhood cancer, little information is available on the long-term consequence of these insults. Twenty-nine patients (mean age 15 +/- 4.3 years) from The Late Effects Follow-Up Clinic For Childhood Cancer study, who had been in continuous, complete remission and off chemotherapy for a minimum of 2 years (mean follow-up 7.2 +/- 3.2) were studied. All patients had normal ejection fractions before and during cancer therapy and all were in New York Heart Association class I at the time of study. Systolic and diastolic functions were assessed by 2-dimensional echocardiography, Doppler flow velocity, and radionuclide angiography, and results were compared with normal control subjects. Left ventricular mass and mass index were significantly reduced in the patient population. Fractional shortening was decreased overall and end-systolic wall stress was much higher in patients than in controls. However, contractility, as assessed by the relation of wall stress to rate-corrected velocity of shortening, was decreased by > or = 2 SDs in only 6 of 28 patients, and the force-mass relation was actually increased in the patient group as a whole. Mitral valve inflow velocities were significantly increased but the pattern was abnormal. These results suggest a pattern consistent with a thin-walled, complaint left ventricle with reduced muscle mass performing under above-normal levels of wall stress. Contractility measurements were normal or increased in the group, but some patients clearly demonstrated development of reduced contractile function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗