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Similar Loss (similar + loss)
Selected AbstractsA modified MPTP treatment regime produces reproducible partial nigrostriatal lesions in common marmosetsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2005Mahmoud M. Iravani Abstract Standard MPTP treatment regimens in primates result in >,85% destruction of nigral dopaminergic neurons and the onset of marked motor deficits that respond to known symptomatic treatments for Parkinson's disease (PD). The extent of nigral degeneration reflects the late stages of PD rather than events occurring at its onset. We report on a modified MPTP treatment regimen that causes nigral dopaminergic degeneration in common marmosets equivalent to that occurring at the time of initiation of motor symptoms in man. Subcutaneous administration of MPTP 1 mg/kg for 3 consecutive days caused a reproducible 60% loss of nigral tyrosine hydroxylase (TH)-positive cells, which occurred mainly in the calbindin-D28k -poor nigrosomes with a similar loss of TH-immunoreactivity (TH-ir) in the caudate nucleus and the putamen. The animals showed obvious motor abnormalities with reduced bursts of activity and the onset of motor disability. However, the loss of striatal terminals did not reflect early PD because a greater loss of TH-ir occurred in the caudate nucleus than in the putamen and a marked reduction in TH-ir occurred in striatal patches compared to the matrix. Examination of striatal fibres following a partial MPTP lesion showed a conspicuous increase in the number and the diameter of large branching fibres in the putaminal and to some extent caudatal matrix, pointing to a possible compensatory sprouting of dopaminergic terminals. In addition, these partially lesioned animals did not respond to acute treatment with L-DOPA. This primate partial lesions model may be useful for examining potential neuroprotective or neurorestorative agents for PD. [source] Removal of N -methylpyrrolidone hydrogen-bonded to polyaniline free-standing films by protonation,deprotonation cycles or thermal heatingPOLYMER INTERNATIONAL, Issue 11 2001Eduardo A Ponzio Abstract Free-standing films of polyaniline (PANI), in an emeraldine base state, prepared by evaporation of polymer solutions in N -methylpyrrolidone (NMP) retain solvent even under dynamic vacuum drying as indicated by transmission Fourier transform infrared (FTIR) spectroscopy, where a band at 1670,cm,1 is clearly observed. Upon protonation,deprotonation cycles in aqueous media the weight of the dry base film decreases indicating gradual loss of NMP. Transmission FTIR spectra shows also the washing out of NMP with a clear decrease in intensity of the hydrogen-bonded >CO stretching band (1670,cm,1) of NMP. During this process the bands between 3500 and 3200,cm,1, assigned to >NH stretching in the PANI backbone, change intensity suggesting that intermolecular hydrogen-bonded >NH, with carbonyl oxygen of NMP, is replaced by free >NH. This is clear evidence of specific interaction of NMP with the emeraldine base. A similar loss of NMP is observed during heating but evidence of polymer degradation is also present. A mechanism is proposed to account for the loss of hydrogen-bonding ability upon protonation which requires delocalization of the radical cations in the protonated films. © 2001 Society of Chemical Industry [source] Loss of Solute Carriers in T Cell-Mediated Rejection in Mouse and Human Kidneys: An Active Epithelial Injury,Repair ResponseAMERICAN JOURNAL OF TRANSPLANTATION, Issue 10 2010G. Einecke T cell-mediated rejection of kidney allografts causes epithelial deterioration, manifested by tubulitis, but the mechanism remains unclear. We hypothesized that interstitial inflammation triggers a stereotyped epithelial response similar to that triggered by other types of injury such as ischemia-reperfusion. We identified solute carrier transcripts with decreased expression in mouse allografts, and compared their behavior in T cell-mediated rejection to native kidneys with ischemic acute tubular necrosis (ATN). Average loss of solute carrier expression was similar in ATN (77%) and T cell-mediated rejection (75%) with high correlation of individual transcripts. Immunostaining of SLC6A19 confirmed loss of proteins. Analysis of human kidney transplant biopsies confirmed that T cell-mediated rejection and ATN showed similar loss of solute carrier mRNAs. The loss of solute carrier expression was weakly correlated with interstitial inflammation, but kidneys with ATN showed decreased solute carriers despite minimal inflammation. Loss of renal function correlated better with decreased solute carrier expression than with histologic lesions (r = 0.396, p < 0.001). Thus the loss of epithelial transcripts in rejection is not a unique consequence of T cell-mediated rejection but an active injury,repair response of epithelium, triggered by rejection but also by other injury mechanisms. [source] Antioxidant capacity of human milk: effect of thermal conditions for the pasteurizationACTA PAEDIATRICA, Issue 8 2008Dolores Silvestre Abstract Aim: Pasteurization is the thermal treatment usually applied in milk banks to eliminate the risk of transmission of infectious agents. The aim of this study was to investigate the effect of heat processing upon the antioxidant properties of human milk. Methods: Milk samples collected from 31 healthy women were subjected to two different pasteurization techniques: Holder pasteurization (63°C for 30 min) and high pasteurization (75°C for 15 sec) and oxidative stress markers (glutathione, glutathione peroxidase activity, malondialdehyde and total antioxidant capacity) were determined in comparison to fresh milk. Results: Malondialdehyde concentration was the same in all samples, while there was a decrease in glutathione concentration and total antioxidant capacity in milk samples subjected to thermal processing versus fresh milk samples. However, the drop in these parameters was seen to be significantly greater when applying Holder pasteurization. Both thermal treatments induced considerable and similar loss of glutathione peroxidase activity. Conclusion: Thermal processing of human milk implies a decrease in its antioxidant properties but, when necessary, high pasteurization should be the election method in terms of milk oxidative status. [source] Coupled FEM and lumped circuit model of the electromagnetic response of coaxially insulated windings in two slot coresEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 6 2007Pär Holmberg Abstract This paper presents a coupled FEM and lumped circuit modelling approach that is primarily intended for high-frequency and overvoltage simulations of rotating electric machines with coaxially insulated windings, such as Powerformer and Motorformer. The magnetic fields and their interaction with the conductors of the winding are simulated with the aid of a FEM-program. The displacement current and its losses are modelled with an external lumped circuit. To consider eddy current losses, the stranded conductors and the laminated steel cores are replaced by homogeneous bodies with similar losses over a wide frequency range. The approach is illustrated and experimentally verified for a set-up with a cable wound around two slot cores. The model agrees well with measurements up to 1,MHz. Copyright © 2007 John Wiley & Sons, Ltd. [source] Mutational changes in S-cone opsin genes common to both nocturnal and cathemeral Aotus monkeysAMERICAN JOURNAL OF PRIMATOLOGY, Issue 7 2007David H. Levenson Abstract Aotus is a platyrrhine primate that has been classically considered to be nocturnal. Earlier research revealed that this animal lacks a color vision capacity because, unlike all other platyrrhine monkeys, Aotus has a defect in the opsin gene that is required to produce short-wavelength sensitive (S) cone photopigment. Consequently, Aotus retains only a single type of cone photopigment. Other mammals have since been found to show similar losses and it has often been speculated that such change is in some fashion tied to nocturnality. Although most species of Aotus are indeed nocturnal, recent observations show that Aotus azarai, an owl monkey species native to portions of Argentina and Paraguay, displays a cathemeral activity pattern being active during daylight hours as frequently as during nighttime hours. We have sequenced portions of the S-cone opsin gene in A. azarai and Aotus nancymaae, the latter a typically nocturnal species. The S-cone opsin genes in both species contain the same fatal defects earlier detected for Aotus trivirgatus. On the basis of the phylogenetic relationships of these three species these results imply that Aotus must have lost a capacity for color vision early in its history and they also suggest that the absence of color vision is not compulsively linked to a nocturnal lifestyle. Am. J. Primatol. 69:757,765, 2007. © 2007 Wiley-Liss, Inc. [source] Thermodynamic Analysis of Receptors Based on Guanidinium/Boronic Acid Groups for the Complexation of Carboxylates, ,-Hydroxycarboxylates, and Diols: Driving Force for Binding and CooperativityCHEMISTRY - A EUROPEAN JOURNAL, Issue 15 2004Sheryl L. Wiskur Dr. Abstract The thermodynamics of guanidinium and boronic acid interactions with carboxylates, ,-hydroxycarboxylates, and diols were studied by determination of the binding constants of a variety of different guests to four different hosts (7,10). Each host contains a different combination of guanidinium groups and boronic acids. The guests included molecules with carboxylate and/or diol moieties, such as citrate, tartrate, and fructose, among others. The Gibbs free energies of binding were determined by UV/Vis absorption spectroscopy, by use of indicator displacement assays. The receptor based on three guanidinium groups (7) was selective for the tricarboxylate guest. The receptors that incorporated boronic acids (8,10) had higher affinities for guests that included ,-hydroxycarboxylate and catechol moieties over guests containing only carboxylates or alkanediols. Isothermal titration calorimetry revealed the enthalpic and entropic contributions to the Gibbs free energies of binding. The binding of citrate and tartrate was investigated with hosts 7,10, for which all the binding events were exothermic, with positive entropy. Because of the selectivity of hosts 8,10, a simple boronic acid (14) was also investigated and determined to be selective for ,-hydroxycarboxylates and catechols over amino acids and alkanediols. Further, the cooperativity of 8 and 9 in binding tartrate was also investigated, revealing little or no cooperativity with 8, but negative cooperativity with 9. A linear entropy/enthalpy compensation relationship for all the hosts 7,10, 14, and the carboxylate-/diol-containing guests was also obtained. This relationship indicates that increasing enthalpy of binding is offset by similar losses in entropy for molecular recognition involving guanidinium and boronic acid groups. [source] | |||||||||||||