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Biomedical subjects

A Esposito

Publications and source records attributed to A Esposito.

At least 55 records · Page 3Linked to original sources
PubMed1998

Lack of type 1 and type 2A myosin heavy chain isoforms in rat slow muscle regenerating during chronic nerve block.

The degeneration-regeneration process was induced by bupivacaine injection in innervated, denervated, and nerve-blocked rat soleus muscles. Nerve block was obtained by superfusion of the sciatic nerve with tetrodotoxin (TTX). Two weeks after bupivacaine injection, immunohistochemical and electrophoretical analyses showed the presence of type 1 myosin heavy chain (MHC) only in innervated regenerated muscles, type 2A in innervated and denervated, but not in TTX-paralyzed muscles, and type 2X under all experimental conditions. The presence of type 1 MHC in the innervated, and its absence in both denervated and TTX-paralyzed muscles were also verified immunohistochemically 1 week after bupivacaine injection. It is concluded that the nerve impulses play a determinant role in the expression of 1 and 2A MHC isoforms in the innervated regenerating muscle. The possible causes of the absence of the type 2A MHC isoform in the TTX-paralyzed muscles are discussed.

Animals↗
PubMed1998

Risk Adjustment for the Medicare program: lessons learned from research and demonstrations.

The Balanced Budget Act (BBA) of 1997 requires numerous changes in Medicare. Medicare's managed care program has been reinvented as "Medicare + Choice," offering an expanded range of delivery system options for beneficiaries and a schedule of payment changes that will dramatically affect managed care plans. Preceding some of these BBA-legislated changes to Medicare were years of research and demonstrations. Risk-adjusted payment in the Medicare + Choice program, which is mandated for implementation in 2000, is one example of a longstanding developmental initiative. This paper provides a brief overview of risk adjustment-related research and demonstration activities carried out by the Health Care Financing Administration (HCFA) since the 1980s, and describes a possible technical approach for the implementation of risk-adjusted Medicare managed care payments in 2000.

Aged↗
PubMed1997

Oxygen radicals can induce preconditioning in rabbit hearts.

Indirect evidence suggests that oxygen radicals may contribute to ischemic preconditioning. We directly investigated whether exposure to oxygen radicals per se, in the absence of ischemia, could reproduce the beneficial effects of ischemic preconditioning on infarct size and on postischemic contractile dysfunction. In one branch of the study, isolated rabbit hearts underwent 30 minutes of total global ischemia and 45 minutes of reperfusion (n=6, control group). A second group, before ischemia/reperfusion, was exposed for 5 minutes to a low flux of oxygen radicals generated by purine/xanthine oxidase (P/XO), followed by a 15-minute washout (n=6). Oxygen radical pretreatment significantly improved postischemic recovery of contractile function. We then investigated in another branch of the study whether this preconditioning effect would also reduce infarct size and whether it was mediated by protein kinase C activation. Control hearts were subjected to coronary artery occlusion for 30 minutes, followed by 2.5 hours of reperfusion (n=6). A second group, before coronary occlusion, was exposed to oxygen radicals and washout as described (n=8). A third group was subjected to oxygen radical infusion, but an inhibitor of protein kinase C (polymyxin B, 50 micromol/L) was administered throughout subsequent ischemia (n=7). A fourth group was exposed to oxygen radicals in the presence of scavengers (superoxide dismutase, 250 U/mL; catalase 500, U/mL; n=8). Pretreatment with oxygen radicals markedly reduced infarct size, from 65+/-19% of risk region in controls to 12+/-4% (P<.05). Protein kinase C inhibition significantly attenuated this effect (infarct size, 37+/-9% of risk region; P<.05 versus P/XO; P=NS versus controls). Oxygen radical-induced preconditioning was prevented by scavengers (infarct size, 55+/-14% of risk region; P<.05 versus P/XO; P=NS versus P/XO+polymyxin B). Our data show that in the absence of ischemia, exposure to low concentrations of oxygen radicals can reproduce the beneficial effects of ischemic preconditioning on infarct size and postischemic recovery of left ventricular function. Thus, oxygen radicals might be potential contributors to ischemic preconditioning.

Analysis of Variance↗
PubMed1997

Plants as a source of salt.

Ecological and ethnobotanical aspects of some halophylous plants are presented. These plants possess several morphophysiological adaptations to face salinity in their habitats. They are a source of salt and could represent new potential crops in saline environments.

Plants↗
PubMed1996

Identification of hypothalamic transcripts upregulated by antidepressants.

Identification of quantitative changes in gene expression that occur in the brain after antidepressant treatment can yield novel molecular markers that may be useful in the diagnosis and treatment of major depression. Using a modification of the differential display polymerase chain reaction, we describe the isolation of two transcripts that are differentially expressed in the brain after an 8-week course of antidepressant administration, compared to saline-treated control animals.

Animals↗
PubMed1996

IL-1 beta, IL-1 receptor type I and iNOS gene expression in rat brain vasculature and perivascular areas.

The mechanism by which IL-1 beta exerts its actions in the brain during systemic inflammation is not fully understood, as neither IL-1 receptor gene expression nor IL-1 binding have been identified in significant levels in key areas that respond to IL-1 beta. Having hypothesized that perivascular nitric oxide (NO) might modulate the effects of systemic IL-1 beta in the brain, we studied the expression of the genes encoding for IL-1 beta, the signal-transducing IL-1 receptor type I (IL-1RI) and inducible NO synthase (iNOS) constitutively and during systemic inflammation in vascular and perivascular regions of the rat brain. Our results show that IL-1RI is constitutively expressed at the interface of the vascular wall and perivascular glia. During systemic inflammation there is induction of IL-1 beta gene expression in the vascular wall, accompanied by perivascular induction of iNOS mRNA. We conclude that during systemic inflammation vascular IL-1 beta, binding to vascular and perivascular IL-1RI receptors, may induce perivascular iNOS gene expression, leading to the production of NO and modulation of the effects of IL-1 beta in the brain. We propose that the vascular and peri-vascular induction of iNOS mRNA by IL-1 beta might represent a mechanism for the modulation of the central nervous system effects of peripheral inflammatory mediators.

Animals↗
PubMed1996

The influence of biomaterials on inflammatory responses to cardiopulmonary bypass.

The nature of cardiopulmonary bypass and the complexity of the inflammatory response make the detection and interpretation of a biomaterial influence difficult. However, if mediation of the inflammatory response is considered to be an appropriate clinical goal, alteration to the biomaterial influence merits further investigation.

Biocompatible Materials↗
PubMed1996

Localization of urocortin messenger RNA in rat brain and pituitary.

Pituitary function is regulated by hypothalamic releasing hormones secreted into hypophyseal-portal blood. A new hypothesis is that pituitary function might also be regulated at the local level by releasing hormones synthesized within the pituitary. Here we show that the pituitary expresses high levels of the gene encoding for urocortin. We suggest that urocortin synthesized by the pituitary may modulate pituitary function, and that adrenocorticotropic hormone (ACTH) secretion is dependent on input not only from the hypothalamus as previously described, but it may also be regulated by urocortin synthesized locally. Urocortin binds to the corticotropin-releasing hormone (CRH) receptor type 1 (CRH-R1) with high affinity and potently stimulates pituitary-adrenal function. Our group and others have previously localized high levels of CRH-R1 mRNA in the pituitary. Using a 35S-labeled rat urocortin riboprobe we have now localized urocortin mRNA in rat brain and pituitary. The finding of urocortin gene expression in the pituitary may help explain why proopiomelanocortin (POMC) mRNA levels are not decreased during hypothalamo-pituitary disconnection, and also describes a new level of complexity in the regulation of hypothalamo-pituitary function. Future studies should consider the possibility that pituitary function might be regulated at the local level by urocortin.

Animals↗
PubMed1995

Low environmental radiation background impairs biological defence of the yeast Saccharomyces cerevisiae to chemical radiomimetic agents.

Background radiation is likely to constitute one of the factors involved in biological evolution since radiations are able to affect biological processes. Therefore, it is possible to hypothesize that organisms are adapted to environmental background radiation and that this adaptation could increase their ability to respond to the harmful effects of ionizing radiations. In fact, adaptive responses to alkylating agents and to low doses of ionizing radiation have been found in many organisms. In order to test for effects of adaptation, cell susceptibility to treatments with high doses of radiomimetic chemical agents has been studied by growing them in a reduced environmental radiation background. The experiment has been performed by culturing yeast cells (Saccharomyces cerevisiae D7) in parallel in a standard background environment and in the underground Gran Sasso National Laboratory, with reduced environmental background radiation. After a conditioning period, yeast cells were exposed to recombinogenic doses of methyl methanesulfonate. The yeast cells grown in the Gran Sasso Laboratory showed a higher frequency of radiomimetic induced recombination as compared to those grown in the standard environment. This suggests that environmental radiation may act as a conditioning agent.

Background Radiation↗
PubMed1994

Tietze's syndrome: a case report and topical methods in diagnostic imaging.

In the present study, we report a recently observed case of Tietze's syndrome. The clinical features of the case and the present methods of diagnostic imaging are discussed. The role and advantages of echography are emphasized, with reference to the syndrome diagnosis and follow-up.

Diagnosis, Differential↗
PubMed1992

Fluoride availability in human saliva after dentifrice use: correlation with anticaries effects in rats.

Studies were conducted to determine fluoride availability in saliva after dentifrice use and to relate this parameter to cariostatic efficacy in rat caries experiments. Three dentifrices--two commercial formulations (Colgate Winterfresh Gel and Crest Dentifrice with Na-Sr-polyacrylate) and an Experimental dentifrice--were compared with respect to salivary fluoride availability. All of the dentifrices tested contained 1100 ppm F as sodium fluoride. It was observed that the Experimental dentifrice and Crest dentifrice with Sr-polyacrylate exhibited low salivary fluoride availability relative to the Colgate Winterfresh Gel. Salivary fluoride availability was assessed by means of two parameters: (a) the fluoride concentration in the dentifrice saliva slurry expectorated after brushing, and (b) the area under the curve of salivary F concentration vs. time for up to two hours after dentifrice use. In two rat caries experiments, it was observed that both the Experimental dentifrice and the Sr-polyacrylate dentifrice provided less cariostatic efficacy than the clinically validated Positive Control (Colgate Winterfesh Gel). Analysis of these data provides further evidence in support of the concept that fluoride availability in saliva following dentifrice use is an important parameter related to anticaries efficacy.

Acrylic Resins↗
PubMed1992

Regional surgery in advanced ovarian carcinoma.

Regional surgery can be defined as "the maximum cytoreduction of all macroscopic tumors developing in the abdominal cavity". The Authors present their experiences with this difficult technique and conclude that regional surgery can improve prognosis.

Female↗
PubMed1991

113Cd nuclear magnetic resonance (NMR) study of the inhibitory effect of methylvinylether/maleic acid (PVM/MA) copolymer on the alkaline phosphatase of Escherichia coli.

The inhibitory effect of PVM/MA copolymer on the alkaline phosphatase (AP) of E. coli was investigated. Kinetic studies indicated that enzyme inhibition was characterized by a reduction in both the Vmax and the Km. Addition of 1 mM zinc or magnesium ions to the reaction prevented inhibition of the enzyme by the copolymer. The inhibitory effect of the copolymer on alkaline phosphatase was also investigated using 113Cd NMR after exchange of the active center metal ions with 113Cd. The resulting Cd(II)6AP exhibited characteristic 113Cd resonances reflecting the environment of the A, B, and C metal binding sites of the enzyme's active center. Addition of copolymer resulted in a 113Cd NMR spectrum which indicated removal of 113Cd from the C site and formation of two distinct forms of the enzyme. Possible explanations for the 113Cd NMR results are discussed.

Alkaline Phosphatase↗
PubMed1991

[Possibility of prenatal ultrasonic diagnosis of growth defects in fetal long bones. Report of a case].

Recent advances in echographic diagnosis and its application during the first three months of pregnancy provide a direct method for assessment in both normal and pathological pregnancies. Given their frequency, the study was focused on the congenital structural anomalies of fetal limbs. The possibility of the repetition of these malformations in the same patient is very high, ranging from 2-25%. It is therefore extremely important to use echographic monitoring during pregnancy in order to observe and measure with great precision the lengths of the limbs and individual bones in fetuses at risk at an early stage of their development.

Adult↗
PubMed1990

In vitro and in vivo anticalculus effects of a triclosan/copolymer system.

The effect of PVM/MA copolymer on hydroxyapatite crystal growth in vitro at 37 degrees C was evaluated. The copolymer provided a 50% inhibition of the growth rate at 35 ppm for 220 minutes. The polymer adsorbed to saliva-coated hydroxyapatite disks and the adsorption was time and concentration dependent. Under exaggerated in vitro conditions, the copolymer did not etch or damage enamel surfaces at pH 5.5 and 7.5. It was highly effective against calculus formation in rats when applied topically yielding a 54% reduction (P less than or equal to 0.01). In beagle dogs, it reduced calculus formation significantly (P = 0.06) over a period of 24 to 28 weeks when applied topically either as a rinse or toothpaste. Collectively, the data indicated that the copolymer was an effective anticalculus agent when applied topically, in the presence of triclosan.

Adsorption↗