Acid-catalyzed addition of alcohols and thiols to bilirubin.
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Acetates↗
Biomedical subjects
D Monti
Publications and source records attributed to D Monti.
Photoaddition of sulphydryl groups to bilirubin in vitro.
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Bilirubin↗
Photochemical addition of N-acetyl-L-cysteine and glutathione to bilirubin in vitro and its relevance to phototherapy of jaundice.
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Acetylcysteine↗
Klinefelter's syndrome in nontwin brothers and maternal XX/XXX mosaicism.
A case of two nontwin brothers, 19 and 17 years old, who had both Klinefelter's syndrome with a chromosomal mosaicism 46 XY/47 XXY, is reported here. The analysis of their mother's karyotype revealed a 46 XX/47 XXX mosaicism. It is hypothesized that the presence of an extra X chromosome in all three subjects could depend on the transmission of two X chromosomes from the mother to the sons or, less likely, on an increased liability to nondisjunction of the X chromosomes during one of the early mitotic divisions in the zygotes.
Adolescent↗
Effect of zinc ions on apoptosis in PBMCs from healthy aged subjects.
Immunosenescence features, such as thymic involution, alteration of T-cell repertoire, autoimmunity and accumulation of memory/effector T cells, may be the result, at least in part, of a zinc deficiency, which is often observed during ageing. Zinc, as essential trace element, affects the immune system function and it is an important regulator of apoptosis of immune cells. In this study we addressed the question whether zinc supplementation in vitro at physiological doses can affect spontaneous and oxidative stress-induced apoptosis in peripheral blood mononuclear cells from subjects of three different age groups: young (mean age 28 years), old (mean age 72 years) and nonagenarians. We studied different parameters related to apoptosis (phosphatydilserine exposure, mitochondrial membrane potential, caspase 3 cleavage) and we found that zinc, while decreasing spontaneous apoptosis, can increase oxidative stress-induced apoptosis in an age-related fashion, being this effect more evident in nonagenarians than in old or young subjects. In particular, zinc can increase late apoptosis/necrosis, a phenomenon that could trigger unnecessary inflammation in vivo. We surmise that these age-associated alterations in susceptibility to apoptosis may be due to a different effect of zinc on T cell subsets, that are altered in very old people, and finally that the zinc deficiency, which is often observed in aged subjects, could be a compensatory mechanism to counteract the inflammatory status of the elderly.
Adult↗
Age-related increase of mitomycin C-induced micronuclei in lymphocytes from Down's syndrome subjects.
Peripheral blood lymphocytes from 7 patients with Down's syndrome (DS; trisomy 21) and 14 healthy age-matched controls were studied for the induction of micronuclei (MN) by the cytokinesis-block method. The spontaneous incidence of MN in lymphocytes from DS subjects was lower than that of control cultures. When lymphocytes were treated with mitomycin C (MMC) at the beginning of the culture period, an increase in MN formation was found in cells from both DS and control subjects. In DS subjects this increase was much more marked than in control donors. This effect had to be ascribed to cells from older DS subjects (37-55 years old), which showed an MMC-induced MN formation that was markedly and significantly higher than that observed in cells from younger (9-16 years old) DS subjects. These data indicate that age has to be considered a major variable when studies on the genetic instability of DS subjects are performed.
Adolescent↗
Apoptosis by 2-chloro-2'-deoxy-adenosine and 2-chloro-adenosine in human peripheral blood mononuclear cells.
Adenosine has profound effects on immune cells and has been implicated in the intrathymic apoptotic deletion of T-cells during development. In order to characterize adenosine effects on quiescent peripheral blood mononuclear cells (PBMC), we have evaluated the ability of the previously characterized adenosine receptor agonist 2-chloro-adenosine (2CA; Ceruti, Barbieri et al., 1997) and of the antineoplastic drug 2-chloro-2'-deoxy-adenosine (2CdA, cladribine) to trigger apoptosis of PBMC. Apoptosis was assessed by morphological changes, DNA fragmentation by agarose gel electrophoresis and appearance of hypodiploid DNA peak by flow cytometry. 2CA (10 microM) and 2CdA (1 microM) induced apoptosis in human PBMC, which are relatively insensitive to apoptosis. For both agents, the effect was concentration- and time-dependent, although 2CdA induced apoptosis more potently than 2CA. Evaluation of mitochondrial function in parallel samples using the mitochondrial membrane-potential-specific dye JC-1 showed that mitochondrial damage followed the same kinetics as apoptosis, hence an early damage of mitochondria is likely not responsible for adenosine-induced death of PBMC. The effect of 2CA was partially prevented by addition of dipyridamole (DP), a nucleoside transport inhibitor, hence some of the apoptotic effect of this nucleoside is, at least in part, due to intracellular action. Alternatively, DP did not affect 2CdA-induced apoptosis, suggesting that 2CdA may enter cells via a DP-insensitive transporter. 5-Iodotubercidin (5-Itu), a nucleoside kinase inhibitor, was also able to partially prevent the action of 2CA and was not able to affect 2CdA-induced apoptosis, suggesting a different role for phosphorylation in 2CA- vs 2CdA-induced apoptosis. To test the role of P1 receptors, agonists and antagonists selective at various P1 receptor subtypes were used. Data suggest that, for 2CA, apoptosis is partially sustained by activation of the A2A receptor subtype, whereas no role is exerted by P1 receptors in 2CdA-dependent apoptosis. Moreover, in these cells, apoptosis could also be triggered through intense activation of the A3 receptor via selective agonists such as 2-chloro-N6-(3-iodobenzyl)adenosine-5'-N-methyluronamide (Cl-IB-MECA), but this mechanism plays no role in either 2CA- or 2CdA-induced apoptosis. On the whole, our results suggest that 2CA and 2CdA follow different pathways in inducing apoptosis of immune cells. Moreover, our data also suggest that there are at least three different ways by which adenosine derivatives may induce apoptosis of human PBMC: (i) through an A2A-like extracellular membrane receptor; (ii) through entry of nucleosides into cells and direct activation of intracellular events involved in the apoptotic process; or (iii) through activation of the A3 receptor.
2-Chloroadenosine↗
Phantom dosimeters examined by NMR analysis: a promising technique for 3-D determinations of absorbed dose.
Fricke-infused agarose gels examined by nuclear magnetic resonance (NMR) analysis are inspected, and their response to gamma-rays, thermal neutrons and protons, at radiotherapy dose levels, is examined. The gel composition is chosen with attention to the tissue equivalence for the radiation fields of interest; this problem is crucial, in particular, for thermal neutrons. The feasibility of three-dimensional determination of absorbed dose in Fricke-gel phantoms is investigated, and the possibility of employing the technique in conformal therapies, such as boron neutron capture therapy (BNCT) and proton therapy, is tested. Isodose curve determination in a cylindrical gel phantom exposed to thermal neutrons is presented. A method for depth-dose profiling in tissue exposed to protons is described, and some results are reported which show that the depth-dose data are determinable with millimetric precision. Results obtained with a spectrophotometer from gel augmented with a metal indicator are reported and discussed also. These results show the possibility of obtaining a very sensitive dosimetry technique consisting of spectrophotometric analysis of such a Fricke-gel.
Absorption↗
Phagocytosis of hemozoin (native and synthetic malaria pigment), and Plasmodium falciparum intraerythrocyte-stage parasites by human and mouse phagocytes.
Hemozoin, the detoxification product of hemoglobin heme, piles up as electron-dense material in the food vacuole (FV) of intraerythrocytic malaria parasites (malaria pigment). In infected individuals, pigment is internalized by both circulating and resident phagocytes, thus modulating their functions. Synthetic beta-hematin, prepared in vitro from hematin (ferriprotoporphyrin IX hydroxide) in acidic condition, is spectroscopically identical to hemozoin. In this electron microscopy study, native and synthetic hemozoin also prove to be morphologically indistinguishable (large polygonal crystals with apparent transverse banding) and to undergo the same process when internalized by phagocytes (primarily a direct uptake of crystals, similar to what is described for asbestos fibers). On the contrary, whole parasites appear to follow a classical endocytic pathway. This suggests that there may be differences between the ingestion of free particles and whole parasites in terms of modulation of phagocytes' functions.
Animals↗
Rufloxacin eyedrops: effect of different formulations on ocular pharmacokinetics in rabbits.
PURPOSE: To evaluate the aqueous humor pharmacokinetics of rufloxacin in rabbits after topical administration of different formulations, and to individuate the ones showing the best pharmacokinetic profile. METHODS: Six formulations were instilled in rabbit eyes: two pH 7.2 suspensions of non-salified rufloxacin base, or zwitterion (RUF), one of which was viscosized with tamarind seed polysaccharide (TSP); two pH 7.2 solutions of RUF obtained using hydroxypropyl-beta-cyclodextrin (CD), one of which was viscosized with TSP; and two pH 5.0 solutions of rufloxacin hydrochloride (RUF-HCl ), one of which was viscosized with TSP. At different times after administration, samples of aqueous humor were withdrawn and analyzed by high-pressure liquid chromatography. The main pharmacokinetic parameters of RUF in the aqueous humor produced by the different formulations were calculated and statistical differences were assessed. RESULTS: The best results, in terms of aqueous humor bioavailability, were observed with two TSP-viscosized formulations: a solution of the hydrochloride (TSP/RUF-HCl) and a suspension of the base (TSP/RUF), followed by the non-viscosized solution of RUF-HCl. The formulations containing CD-solubilized RUF were much less effective. CONCLUSIONS: The present data confirm the significant availability-enhancing properties of tamarind seed polysaccharide, and indicate that solubilization of RUF with hydroxypropyl-beta-cyclodextrin (CD/RUF) results in decreased drug availability with respect to standard formulations. Two of the TSP-viscosized formulations (RUF suspension and RUF-HCl solution) produced aqueous humor RUF concentrations in the range of activity against Enterobacteriaceae and Pseudomonas aeruginosa, thus warranting further studies on applications of rufloxacin in ocular therapy.
2-Hydroxypropyl-beta-cyclodextrin↗
[Polyblastomatosis of hormone-dependent organs].
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Animals↗
Interaction of bilirubin with small unilamellar vesicles of dipalmitoylphosphatidylcholine.
Interaction of bilirubin with phospholipid bilayers was studied at physiological pH above and below the gel-liquid crystalline phase transition of small unilamellar vesicles of dipalmitoylphosphatidylcholine. Chromatographic, calorimetric and 1H-NMR evidences strongly suggest that dianion form of bilirubin binds to the polar heads of the phosphatidylcholines protruding from the outer leaflet of the vesicles, whilst acid bilirubin, which is insoluble in water, is hydrophobically inserted into the lipophilic region of the bilayers. The surface-bound bilirubin is promptly removed from vesicles, whilst the acid form hydrophobically inserted into the vesicles is firmly bound to the membrane in the gel state. This pool of bilirubin could perturb the chemico-physical properties of the membrane (i.e., fluidity, phase transition, etc. ...) thus contributing to perturbation of the biological properties of living cells.
Bilirubin↗
[Usefulness of the Doppler velocimetry in patients undergoing direct arterial surgery].
Two patients with an atypical and particularly troubled history, due to numerous direct and indirect interventions of vascular surgery, have been monitored in haemodynamic investigation using only Doppler velocimetry. The use of angiography would have necessitated other general anaesthesiae which would have further compromised the already critical conditions of the patients. Doppler velocimetry proved suitable for surgical indication in emergency situations. The value of an arteriograph under general anaesthesia is, however, unquestionable in cases of choice surgery.
Aorta, Abdominal↗
[Unusual aspect of a case of congenital absence of the vagina (Mayer-Rokitansky-Kuster-Hauser syndrome)].
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Adult↗
[Technical considerations of a system of phosphor digital radiography and its cost-effectiveness in a radiology center].
The authors report the technical-applicative characteristics of a storage phosphor system (ADC 70, Ag-fa), experimentally used at the Department of Radiology of the University of Modena (Azienda Ospedaliera Policlinico) and analyze its effects on the center budget. The system was applied to urologic, osteoarticular and thoracic diagnoses, with bedside exams in the latter case. An automatic system (chest changer, Dupont) was used for hospitalized walking patients and for nonhospitalized patients. The data relative to the consumption of films and chemical products and the relative cost were analyzed and It. L. 84,284,782 appeared to have been saved on the annual budget. The data extrapolated from the practical experience of the Modena Radiology Department showed an average 900 exams a month, with 2,019 films being used for conventional radiography versus 918 with the ADC system. Reusing the same evaluation system, the implementation of the same system was simulated in another hospital with different characteristics (Azienda USL Imola, Bologna). The final result was an estimated annual saving of about It L. 83,000,000. The total workload of X-ray rooms afferent to the developing ADC system was considered for both departments and the cost of the conventional system compared with that of the digital system with laser print: about 197 square meters of film were used monthly with the conventional system, versus 55 after the implementation of the ADC system. The estimated figures were about 424 versus 235 for the implementation of the same ADC system in the second hospital. 9-10% was the estimated saving of the ADC system versus the conventional one thanks to fewer of the so-called refuses-i.e., exams that must be repeated; 63-81% chemical products were also saved because fewer films were developed. The cost-effectiveness of the ADC system in the budget of the two centers is stressed, with about 40% total saving. In particular, using the transfer price system for intermediate departments by Regione Emilia Romagna, the annual full cost per exam (weight = 1) decreased from It. L. 4,343 to It. L. 4,120 before and after the ADC system implementation, respectively.
Cost-Benefit Analysis↗