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M Kaplan

Publications and source records attributed to M Kaplan.

At least 73 records · Page 4Linked to original sources
PubMed2000

Sideward flow in Au+Au collisions between 2A and 8A GeV

Using the large acceptance Time Projection Chamber of experiment E895 at Brookhaven, measurements of collective sideward flow in Au+Au collisions at beam energies of 2A, 4A, 6A, and 8A GeV are presented in the form of in-plane transverse momentum and the first Fourier coefficient of azimuthal anisotropy v(1). These measurements indicate a smooth variation of sideward flow as a function of beam energy. The data are compared with four nuclear transport models which have an orientation towards this energy range. All four exhibit some qualitative trends similar to those found in the data, although none show a consistent pattern of agreement within experimental uncertainties.

Journal Article↗
PubMed2000

Bombarding energy dependence of pi(-) interferometry at the brookhaven AGS

We present the first excitation function of pi(-) intensity interferometry at Alternating Gradient Synchrotron (AGS) energies (2-8 A GeV). The sensitivity of the multidimensional correlation functions to the geometry and dynamics of the pion-emitting system provides a stringent test of transport models of heavy ion collisions. Detailed comparisons with a realistic transport model, both with and without an explicit nuclear mean field, suggest that the beam energy evolution in the reaction dynamics is different in the model than in the data. A significantly increased pi(-) emission time scale, which has been suggested as a signal of the onset of the transition to quark-gluon plasma, is not observed.

Journal Article↗
PubMed2000

Oxidized monocyte-derived macrophages in aortic atherosclerotic lesion from apolipoprotein E-deficient mice and from human carotid artery contain lipid peroxides and oxysterols.

Oxidative stress is thought to play an important role in atherogenesis. The present study demonstrated, for the first time, that macrophages (originally derived from blood monocytes) isolated from aortas of the atherosclerotic apolipoprotein E deficient (E degrees ) mice or from human carotid artery, are oxidized as they contain lipid peroxides and oxysterols. The major oxysterol in arterial macrophages was found to be 7-ketocholesterol (51% of total oxysterols). To find out whether lipid peroxidation of monocytes occurs in vivo already in the blood, we analyzed the oxidative state of monocytes derived from E degrees mice in comparison to monocytes from control mice. Cellular lipid peroxides and total oxysterols were four and sevenfold higher respectively, in monocytes derived from E degrees mice in comparison to monocytes from control mice. The results of the present study thus demonstrated the presence of lipid-peroxidized monocytes already in the blood, which are further oxidized in the arterial wall after their conversion into macrophages. The arterial oxidized macrophages could be considered key contributors to foam cell formation, the hallmark of early atherosclerosis.

Animals↗
PubMed2000

A Brunswikian evolutionary-developmental theory of adolescent sex offending.

A Brunswikian Evolutionary-Developmental model was developed to relate the sex offending behavior of adolescents to other forms of social deviance, tracing a history of repeated frustration and failure in various competitive sexual strategies and escalation to more extreme means of obtaining sexual gratification. Four hypothetical constructs were proposed as stages in the development of sexual criminality: (1) Psycho-Social Deficiency (PSD); (2) Non-Criminal Sexuality (NCS); (3) Non-Sexual Criminality (NSC); and (4) Sexual Criminality (SC). Significant direct and indirect pathways led from PSD to SC through both NCS and NSC, each time facilitated by an interaction with PSD. Although the causal orders between stages remain equivocal, the current results are consistent with our theory and establish the heuristic value of our theoretical approach, providing empirical support for otherwise counterintuitive predictions. This interpretation also offers hope for focusing preventative intervention at one major root cause of this unfortunate cascade of consequences, Psycho-Social Deficiency.

Adolescent↗
PubMed2000

Macrophage plasma membrane chondroitin sulfate proteoglycan binds oxidized low-density lipoprotein.

Lipoprotein interactions with macrophage proteoglycans (PGs) is believed to play an important role in the cellular uptake of lipoproteins and in macrophage cholesterol accumulation. Recently, we have shown the participation of macrophage plasma membrane glycosaminoglycans (GAGs) in the cellular uptake of oxidized LDL (Ox-LDL). The aim of the present study was to identify the specific cell surface proteoglycans involved in this interaction. J-774 A.1 macrophage-like cell line plasma membrane proteoglycans were isolated by anion exchange chromatography from cells that were prelabeled with [35S]sodium sulfate. Using Sepharose 6B chromatography, cell surface major proteoglycans were identified as chondroitin sulfate (CS) proteoglycans (77%) and heparan sulfate (HS) proteoglycans (23%). Binding rates of these 35S-labeled proteoglycans to Ox-LDL and to native LDL were analyzed by their ability to bind lipoproteins coupled to a CnBr-activated Sepharose CL-4B chromatography. Of the total labeled cell surface proteoglycans added to the column, 57% were bound to the Sepharose-coupled Ox-LDL, whereas 73% of the cell surface proteoglycans were bound to the Sepharose-coupled native LDL. Binding of the plasma membrane macrophage 35S-labeled proteoglycans to Ox-LDL was inhibited by adding increasing concentrations of non-labeled chondroitin sulfate, or by pretreatment of the 35S-labeled proteoglycans fraction with chondroitinase ABC. In contrast, neither the addition of non-labeled heparan sulfate, nor pretreatment of the labeled proteoglycans fraction with heparinase III, had any significant effect on proteoglycan binding to Ox-LDL. These findings were further supported by using mutant cells characterized by specific glycosaminoglycan deficiencies. Ox-LDL binding and degradation by mutant 745 CHO cells which are characterized by a deficiency in both heparan sulfate and chondroitin sulfate, was decreased by 28 and 27% respectively, compared to the binding of Ox-LDL to the wild-type CHO cells. Ox-LDL binding and degradation by mutant 677 CHO cells, which lack heparan sulfate but have increased levels of chondroitin sulfate, however, was found to be increased by 29 and 19%, respectively, compared to Ox-LDL binding to the wild-type CHO cells. Finally, analysis of the cell surface proteoglycans in macrophages that were subjected to oxidative stress, by their preincubation with angiotensin II, exhibited a 51-59% increase in their cell surface proteoglycan content, with a major effect on chondroitin sulfate proteoglycans. The present study thus demonstrated that Ox-LDL can specifically bind to macrophage surface chondroitin sulfate proteoglycans, and the macrophage content of this proteoglycan is increased under oxidative stress. The interaction between macrophage chondroitin sulfate proteoglycans and Ox-LDL can contribute to enhanced uptake of Ox-LDL with the formation of cholesterol-loaded foam cells, and accelerated atherosclerosis.

Binding Sites↗
PubMed2000

Radiology in the diagnosis and therapy of gastrointestinal bleeding.

Major breakthroughs in catheter and guidewire design as well as improvements in angiographic x-ray equipment currently allow interventional radiologists to diagnose massive life-threatening upper and lower GI hemorrhage and to stop the bleeding safely and effectively using superselective catheterization and microcoil embolization. For chronic or recurrent GI bleeding, when endoscopy is unrevealing or equivocal, barium studies, CT scanning, nuclear medicine studies, and angiography can help determine the cause of bleeding. A multidisciplinary approach, including the gastroenterologist, radiologist, and surgeon, is extremely helpful in managing GI bleeding, particularly in high-risk patients or patients presenting as diagnostic dilemmas.

Angiography↗
PubMed2000

An anatomopathologic study of membranous septum aneurysms and significance of their surgical treatment.

THE PURPOSE OF THE STUDY: We analyzed 14 patients with membranous septal aneurysms presenting with a left-to-right communication, by comparing the angiographic, operative and pathological findings. We decided to use medical treatment on two patients and operated on the rest (12 cases). BASIC METHODS: The mean age of the patients was 19+/-9 yr; nine were female, five were male. Cine-angiography of all patients revealed a saccular abnormality protruding into the right ventricle at the uppermost part of the interventricular septum, just below the aortic valve. The sac had the appearance of a glove finger, a cauliflower, a diverticulum, or it was dome-shaped on angiography. PRINCIPAL FINDINGS: Perioperative exploration revealed a perforated true aneurysmal sac in seven patients. In three patients, the perimembranous tissues were severely fibrotic, thickened or had more than one perforation. Two patients had a defect under the septal leaflet of the tricuspid valve at the postero-inferior part of the septum, hidden between the chordae of the valve. CONCLUSIONS: Defining the membranous septal abnormalities clearly is not always possible by cine-angiography. Echocardiography provides additional information. Pathological examination of the resected specimens showed almost total loss of elastic fibers and extensive accumulation of mucopolysaccharides.

Adolescent↗
PubMed2000

Solomon Carter Fuller, M.D. (1872-1953): American pioneer in Alzheimer's disease research.

The appointment of Alois Alzheimer to Emil Kraepelin's clinic and laboratory at the Royal Psychiatric Hospital, University of Munich in 1903 offered new opportunities for clinical and pathological studies of the brain. At the opening of the facility in 1904, Alzheimer selected five foreign visiting students as his graduate research assistants, among whom was an American, Dr. Solomon Carter Fuller. A glimpse of Fuller's background as an African-American (born in Liberia) at the turn of the century, his continuing research after leaving Germany in 1906, and his critical view of the Alzheimer dementia entity are recounted. He was held in high esteem as a practicing neuropsychiatrist and teacher in the Boston area.

Alzheimer Disease↗
PubMed2000

Pomegranate juice consumption reduces oxidative stress, atherogenic modifications to LDL, and platelet aggregation: studies in humans and in atherosclerotic apolipoprotein E-deficient mice.

BACKGROUND: Dietary supplementation with nutrients rich in antioxidants is associated with inhibition of atherogenic modifications to LDL, macrophage foam cell formation, and atherosclerosis. Pomegranates are a source of polyphenols and other antioxidants. OBJECTIVE: We analyzed, in healthy male volunteers and in atherosclerotic apolipoprotein E-deficient (E(0)) mice, the effect of pomegranate juice consumption on lipoprotein oxidation, aggregation, and retention; macrophage atherogenicity; platelet aggregation; and atherosclerosis. DESIGN: Potent antioxidative effects of pomegranate juice against lipid peroxidation in whole plasma and in isolated lipoproteins (HDL and LDL) were assessed in humans and in E(0) mice after pomegranate juice consumption for </=2 and 14 wk, respectively. RESULTS: In humans, pomegranate juice consumption decreased LDL susceptibility to aggregation and retention and increased the activity of serum paraoxonase (an HDL-associated esterase that can protect against lipid peroxidation) by 20%. In E(0) mice, oxidation of LDL by peritoneal macrophages was reduced by up to 90% after pomegranate juice consumption and this effect was associated with reduced cellular lipid peroxidation and superoxide release. The uptake of oxidized LDL and native LDL by mouse peritoneal macrophages obtained after pomegranate juice administration was reduced by 20%. Finally, pomegranate juice supplementation of E(0) mice reduced the size of their atherosclerotic lesions by 44% and also the number of foam cells compared with control E(0) mice supplemented with water. CONCLUSION: Pomegranate juice had potent antiatherogenic effects in healthy humans and in atherosclerotic mice that may be attributable to its antioxidative properties.

Adult↗
PubMed2000

Predischarge bilirubin screening in glucose-6-phosphate dehydrogenase-deficient neonates.

OBJECTIVE: To assess the validity of predischarge serum bilirubin values in determining or predicting hyperbilirubinemia in glucose-6-phosphate dehydrogenase (G-6-PD)-deficient neonates, and to facilitate appropriate discharge planning. METHODS: Serum total bilirubin values were determined between 44 and 72 hours of life in a cohort of term, healthy neonates at high-risk for G-6-PD deficiency but with no other risk factors for hyperbilirubinemia. Percentile-based bilirubin nomograms were constructed for G-6-PD-deficient infants and normal infants according to age at sampling. The incidence of hyperbilirubinemia (serum bilirubin value > or =256 micromol/L [15 mg/dL]) for each group was determined according to the percentiles for that group. RESULTS: In both G-6-PD-deficient neonates (n = 108) and control neonates (n = 215) with serum bilirubin values <50th percentile for age, the incidence of hyperbilirubinemia was low in the G-6-PD-deficient neonates, with no measurable incidence in the controls. The incidence of hyperbilirubinemia became clinically consequential, and significantly higher in the G-6-PD-deficient groups, when the percentiles were > or =50: for those in the 50% to 74% range the incidence was moderate (23%) for the G-6-PD-deficient and small (7%) for the control infants (relative risk, 3.29; 95% confidence interval, 1.01-10.67). Among those infants > or =75th percentile, 82% of the G-6-PD-deficient infants, compared with 25% of the control infants, were either already hyperbilirubinemic at the time of screening or subsequently developed hyperbilirubinemia (relative risk, 3.23; 95% confidence interval, 1.99-5.24). CONCLUSIONS: Timed, predischarge serum bilirubin screening can be used to identify G-6-PD-deficient neonates at low, intermediate, or high-risk of developing severe neonatal hyperbilirubinemia, and thus offer a selective approach to the discharge and follow-up surveillance of these infants.

Bilirubin↗
PubMed2000

The relationship of Internet use to depression and social isolation among adolescents.

The present study investigated whether higher levels of Internet use are associated with depression and social isolation among adolescents. Eighty-nine high school seniors were administered a questionnaire that measured low (less than 1 hour per day), moderate (1-2 hours per day), and high (more than 2 hours per day) Internet use; relationships with mother, father, and peers; and depression. Low Internet users, as compared with high users, reported better relationships with their mothers and friends.

Adolescent↗
PubMed2000

Moderate involvement in sports is related to lower depression levels among adolescents.

Sports involvement has been found to be related to social and psychological well-being in Icelandic adolescents. The present study investigated whether similar relationships exist for American adolescents. A group of 89 high school seniors completed a questionnaire that gathered data on sports involvement, depression, intimacy with parents and friends, and grade point average. It was found that the moderate sports involvement group (3 to 6 hours per week) had lower depression scores than did the low sports involvement group (2 hours or less per week). The findings are discussed.

Adolescent↗