Biomedical subjects
S Kaplan
Publications and source records attributed to S Kaplan.
Chromosome mosaicism in a child with features characteristic of the 'Cat Cry' syndrome.
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Multiple-line single-reservoir automatic cardiotomy blood return system.
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Genetic code: the 'nonsense' triplets for chain termination and their suppression.
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Amber suppressors: efficiency of chain propagation and suppressor specific amino acids.
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Regional myocardial blood flow and cardiac mechanics in dog hearts with CO2 laser-induced intramyocardial revascularization.
Laser-induced intramyocardial revascularization (LIR) has been used to promote direct communications between blood within the ventricular cavity and that of the existing myocardial vasculature in an attempt to increase perfusion in patients with ischemic heart disease. This study was conducted to measure the effects of LIR channels on regional myocardial flood flow (microspheres), cardiac mechanics (sonomicrometers), and myocardial tissue pressures in 18 dogs. Under baseline hemodynamic conditions (mean HR = 165.2 +/- 11.4 bpm, LVP = 123.6 +/- 22.9/4.0 +/- 1.8 mm Hg, AoP = 112.8 +/- 27.1/77.0 +/- 22.5 mm Hg), myocardial blood flow in laser-treated tissue (mean = 1.11 +/- .10 cc/min/gm before laser; .71 +/- .19 cc/min/gm after laser) was reduced as compared to blood flow in control tissue (mean = 1.12 +/- .15 cc/min/gm before laser; 1.25 +/- .22 cc/min/gm after laser). Regional myocardial systolic shortening (11.32% +/- 3.82% before laser; 7.49% +/- 2.86% after laser) was decreased by 33%. During simultaneous reversible ligation of the LAD and LCCA for 2 min, when intramyocardial channels represented the only tissue access for the injected microspheres, blood flow in laser-treated tissue was not increased above that of the control non-lasered tissue. However, regional blood flow was greater in laser-treated ischemic tissue (mean = .61 +/- .12 cc/min/gm) than in untreated ischemic areas (mean = .04 +/- .03 cc/min/gm) when left ventricular pressure (LVP) was acutely elevated (mean SLVP = 207.0 +/- 16.1 mm Hg). Using these measurements, a model is proposed to predict regional systolic pressure gradients between the left ventricular cavity and coronary intramyocardial vasculature required to permit restoration of blood flow to ischemic myocardium. We conclude that improved perfusion via laser-induced intramyocardial channels does not occur in otherwise normal myocardium exposed to acute coronary ligation and only small improvements in perfusion are noted when LVP is significantly elevated. Consideration of further clinical application of this approach is seriously cautioned awaiting additional experimental studies.
Electrocardiography and 24-hour electrocardiographic ambulatory recording (Holter monitor) studies in children infected with human immunodeficiency virus type 1. The Pediatric Pulmonary and Cardiac Complications of Vertically Transmitted HIV-1 Infection Study Group.
Limited data are available on the electrocardiogram and ambulatory electrocardiogram recording (Holter) in children infected with the human immunodeficiency virus type 1 (HIV-1). The purpose of this study was to estimate the prevalence and cumulative incidence of rhythm and conduction abnormalities in HIV-1-infected children. Electrocardiograms and Holter monitoring studies were performed annually on 205 HIV-1-infected children enrolled after 28 days of life (group I), 93 HIV-1-infected infants enrolled during pregnancy or during the first 28 days of life (group IIa), and 463 HIV-1-uninfected infants enrolled during pregnancy or during the first 28 days of life (group IIb). The 5-year cumulative incidence in the group I children of second-degree atrioventricular block or supraventricular or ventricular tachycardia was 13.4%, and the 5-year incidence was higher for the older infected group I children (16.8% for children > or =4 years old at first study and 11.4% for children <4 years, p = 0.04). The mean corrected QT interval was also longer for the older infected group I children (p = 0.002) and prolonged in the HIV-1-infected compared to the HIV-1-uninfected group II children (p = 0.02). None of the children had atrial fibrillation or flutter. Arrhythmias are uncommon in children infected with HIV-1 and in children of HIV-1-infected mothers and the arrhythmias identified tend to be benign. Therefore, routine Holter monitoring does not appear to be indicated in asymptomatic children.
Cardiac, aortic, and pulmonary arteriopathy in HIV-infected children: the Prospective P2C2 HIV Multicenter Study.
Arteriopathy in human immunodeficiency virus (HIV)-infected patients is being increasingly recognized, especially in children. However, few studies have histologically evaluated the coronary arteries in HIV-infected children, and none have systematically assessed the aorta and pulmonary arteries. The coronary arteries, thoracic aorta, and the main and branch pulmonary arteries from the postmortem hearts of 14 HIV-infected children were systematically reviewed for vasculopathic lesions and compared with 14 age-matched controls. Findings from the HIV-infected children were compared with clinical, laboratory, and other postmortem findings. Coronary arteriopathy, seen in seven (50%) of the HIV-infected children, was primarily calcific, and it was associated with decreased CD3 and CD4 peripheral blood counts. Large vessel arteriopathy, seen in 9 (64%) of the 14 HIV-infected children, was primarily centered on the vasa vasorum and consisted mainly of medial hypertrophy and chronic inflammation. Large vessel lesions were associated with increased left ventricular mass z-scores (P = 0.02), and 78% of patients with large vessel arteriopathy had postmortem cardiomegaly. Coronary and large vessel arteriopathies are common in pediatric HIV-infection and have different clinicopathologic features suggesting different pathogenesis.
In vitro effects of an acyltripeptide, FK565, on antitumor effector activities and on metabolic activities of human monocytes and granulocytes.
In vitro effects of an immunostimulatory acyltripeptide, FK565, on antitumor and metabolic activities of human leukocytes were studied. Monocyte cytotoxicity against A375 melanoma targets was significantly increased following pretreatment with FK565 at concentrations of 1 microgram/ml or more. The tripeptide also up-regulated anti-tumor cytostasis by monocytes and showed a strong stimulatory effect on superoxide generation by resting monocytes over a wide range of FK565 concentrations after 18 h preincubation. The monocyte preparations contained an average of 76% LeuM3+HLA-DR+, 12% LeuM3+HLA-DR- and 10% LeuM3-HLA-DR+ cells, and this phenotype distribution was not altered after incubation with FK565. At concentrations above 1 microgram/ml and after 2 h preincubation, FK565 also increased superoxide generation by resting but not stimulated granulocytes. Pre-exposure of cultured bovine endothelial cells to the peptide resulted in a significant inhibition of fMLP-stimulated granulocyte adherence to these cells. These data indicate that in vitro incubation of human monocytes and granulocytes with FK565 (0.1-100 micrograms/ml) had resulted in simultaneous up-regulation of several anti-tumor functions mediated by these cells.
Noninvasive techniques in pediatric cardiovascular disease.
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Posttraumatic stress disorder in mothers of pediatric cancer survivors.
Prevalence of posttraumatic stress disorder (PTSD) in 24 mothers of pediatric cancer survivors was compared with its prevalence among 23 mothers of healthy children. Significantly more mothers of pediatric cancer survivors were diagnosed with lifetime PTSD. Significant differences were also found in lifetime arousal, as well as current and lifetime reexperience and avoidance symptom clusters. Significant difference existed in the distribution of the number of prediagnosis high-magnitude events experienced by the mothers diagnosed with current PTSD as compared with the prediagnosis experience of the mothers who were not diagnosed with current PTSD. Illness severity, level of perceived family and extrafamilial social support, and Symptom Checklist-90-Revised global severity index scores did not significantly differ in the PTSD-positive and PTSD-negative groups.
Identification of PTSD in cancer survivors.
The authors measured the rate and determinants of posttraumatic stress disorder (PTSD) in a group of cancer survivors. Patients who had a history of cancer diagnosis with at least 3 years since diagnosis, receiving no active treatment, such as chemotherapy or radiation, were interviewed (N = 27). Patients, who were part of the DSM-IV PTSD field trial, were compared with a community-based control group matched for age and socioeconomic status. One member of the survivor group (4%) and no members of the control group met criteria for current PTSD (NS). Six of the survivors (22%) and no control subjects met lifetime criteria (P < 0.02). Cancer patients have a higher rate of PTSD than found in the community. Symptoms closely resemble those of individuals who have experienced other traumatic events.
Post-traumatic stress disorder in physically abused adolescents.
OBJECTIVE: In an investigation of the prevalence of post-traumatic stress disorder (PTSD), other Axis I psychiatric disorders, and social and behavioral difficulties, 27 physically abused adolescents were compared with 27 nonabused controls who were recruited through random-digit dialing procedures. METHOD: The Structured Clinical Interview for Diagnosis (PTSD module), Kiddie-Schedule for Affective Disorders and Schizophrenia, and Youth Self-Report were administered to all subjects; mothers were interviewed regarding their adolescent's behavior using the Kiddie-Schedule for Affective Disorders and Schizophrenia for School-Age Children and Child Behavior Checklist. RESULTS: The three physically abused adolescents who received a diagnosis of PTSD on the PTSD module of the Structured Clinical Interview for Diagnosis reported their PTSD symptoms were in reaction to extrafamilial sexual assaults and not to physical abuse. In contrast, the abused adolescents showed significantly higher prevalence rates of depression, conduct disorder, internalizing and externalizing behavior problems, and social deficits. CONCLUSIONS: Findings suggest that physically abused adolescents may be more at risk for behavioral and social difficulties than for PTSD.
Compliance and durability in pressure garments.
This study examined the pressure volumetric characteristics (compliance) of Jobst (Jobst Institute, Toledo, Ohio), Barton-Carey (Barton-Carey Co., Perrysburg, Ohio), and Tubigrip (SePro Healthcare Inc., Moorestown, N.J.) pressure garments for arms after repeated saturation with lubricating substances and repeated washing/drying cycles. The three treatment groups were each composed of one sleeve from each of the manufacturers and were subjected to 20 washing/drying cycles. In addition, the sleeves in treatment groups 2 and 3 were saturated with cocoa butter and Lubriderm moisturizer, respectively, before each cycle. Circumferential measurements were taken on the proximal forearm of the sleeve at varying degrees of pressure with a Grafco standard sphygmomanometer (Graham Field Inc., Hauppauge, N.Y.) and a Gulick anthropometric tape measure (Creative Engineering, Plymouth, Mich.). Measurements were taken initially and after every fifth washing/drying cycle. Analysis of variance revealed significant results for the main effects and some interactions at the 0.01 level. Overall results showed little change in the Jobst and Barton-Carey garments, whereas the Tubigrip garments displayed an inconsistent pattern.
A new combination therapy for selective and prolonged antiplatelet effect: results in the dog.
This study characterizes the effect of dazmegrel, a thromboxane synthetase inhibitor, on platelet function in the dog and introduces its potential use in combination with aspirin therapy. Ex vivo testing of dazmegrel alone was performed with three dosages and three administration regimens. Platelet aggregation response, malondialdehyde formation and prostaglandin metabolites generation were evaluated. To maintain complete thromboxane A2 inhibition, dazmegrel had to be given 3 times per day at dosages of not less than 6 mg/kg. The same result was achieved with a single daily administration of combined dazmegrel and aspirin in equal dosages of 3 mg/kg. Dazmegrel, both alone and with aspirin, increased and sustained heightened levels of prostacyclin, unlike the simultaneous inhibition of both prostaglandin metabolites seen with aspirin therapy alone. Because the combination of dazmegrel and aspirin effectively blocks thromboxane A2 formation and also enhances prostacyclin formation, the synergistic action of these agents increases their combined antiplatelet effect to a level not attainable by either agent alone. The significance of this combined therapy warrants further experimental study and may soon merit clinical trial for the prevention of stroke and other major thrombotic complications.
Aedes aegypti in Tucson, Arizona.
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The Mustard procedure for transposition of the great vessels.
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E-hubs: the new B2B (business-to-business) marketplaces.
Electronic hubs--Internet-based intermediaries that host electronic marketplaces and mediate transactions among businesses--are generating a lot of interest. Companies like Ariba, Chemdex, and Commerce One have already attained breathtaking stock market capitalizations. Venture capitalists are pouring money into more business-to-business start-ups. Even industrial stalwarts like GM and Ford are making plans to set up their own Web markets. As new entrants with new business models pour into the business-to-business space, it's increasingly difficult to make sense of the landscape. This article provides a blueprint of the e-hub arena. The authors start by looking at the two dimensions of purchasing: what businesses buy--manufacturing inputs or operating inputs--and how they buy--through systematic sourcing or spot sourcing. They classify B2B e-hubs into four categories: MRO hubs, yield managers, exchanges, and catalog hubs, and they discuss each type in detail. Drilling deeper into this B2B matrix, the authors look at how e-hubs create value--through aggregation and matching--and explain when each mechanism works best. They also examine the biases of e-hubs. Although many e-hubs are neutral--they're operated by independent third parties--some favor the buyers or sellers. The authors explain the differences and discuss the pros and cons of each position. The B2B marketplace is changing rapidly. This framework helps buyers, sellers, and market makers navigate the landscape by explaining what the different hubs do and how they add the most value.