51
|
Solvation enthalpies as descriptors of structure--in vitro percutaneous permeation relationship of benzoxazinones regioisomers. FARMACO (SOCIETA CHIMICA ITALIANA : 1989) 2000; 55:563-8. [PMID: 11132734 DOI: 10.1016/s0014-827x(00)00048-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The aim of this work was to correlate the in vitro human skin permeability, expressed as the permeability coefficient (Kp), and some physicochemical parameters of a new series of benzoxazinones. The in vitro human skin permeability of 14 substances, including regioisomers with CH3, OH, OCH3, and Cl groups in different positions on the aromatic ring, was determined. The modified Franz diffusion cell method was used. The Kp values were in the range 0.14-8.24 cm/h, showing a strong dependence on the position and type of substituent. Physicochemical descriptors usually referred in literature, such as log P, molecular weight and volume (MV), hydrogen bond donor (Hd) and acceptor activity (Ha), and molecular refractivity were considered, with the addition of solvation enthalpy (delta deltaHsolv). Delta deltaHsolv is defined as the difference between formation enthalpies in water and octanol. The algorithm with the best correlation between Kp and physicochemical descriptors was calculated, taking into account the differences observed among the regioisomers. The algorithm obtained with delta deltaHsolv had a good correlation (r2 = 0.749, F = 16.43, P = 0.0005), comparable with the equation, proposed by Potts and Guy, based on MV, Hd and Ha (r2 = 0.830, F = 16.3, P = 0.0004).
Collapse
|
52
|
Abstract
Even if a specific directive has been approved many years ago, the situation of self-medication products (OTC) in EU countries is still far from being harmonized. In Italy the market is lower than that of most other countries; in order to solve some of the major problems that led to this situation a guideline, concerning the criteria for the definition of an OTC product, and the characteristics of the label and the package leaflet, was recently published. In this document the characteristics of OTC, such as composition, indications and duration of the treatment are assessed. The European Commission has recently published a guideline on the readability of labels and package leaflets of medicinal products for human use. The two documents stated the same principles and the Italian document is in agreement with the European guidelines. In this paper the Italian situation of OTC products (definition and presentation) is presented and discussed.
Collapse
|
53
|
Abstract
Industrial medicinal products are not always available for the treatment of some specific patients or diseases. Appropriate research on orphan drugs, neglected doses or administration routes and patients' sensitivity to excipients, as an example, might lead to interesting results in this respect. In the United States, a specific legislation on orphan drugs dates back to 1983; in the European Union, regulations are currently being studied. The industrial production of orphan drugs might be improved following the adoption of adequate incentives. New regulations should also take care of neglected doses, and stimulate the preparation of galenic products, as an example by including a number of monographs on orphan drugs in Pharmacopoeias and National Formularies. As a matter of fact, magistral and officinal preparations made in community and hospital pharmacies in accordance with a medical prescription or with the prescription of a Pharmacopoeia or an Official Formulary, can represent an effective alternative. In this paper, the regulations enforced in the USA and Japan, the European situation, possible incentives to the industry and the role of galenic products will be discussed.
Collapse
|
54
|
|
55
|
Development of local patches containing melilot extract and ex vivo-in vivo evaluation of skin permeation. Eur J Pharm Sci 2000; 10:111-7. [PMID: 10727876 DOI: 10.1016/s0928-0987(99)00094-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Melilot extract could be effective in treating localised varicose syndrome or capillary fragility. The monolayer patch was selected to obtain a prolonged release of coumarin contained in the phytocomplex. Two types of methacrylic patches (patch 1 based on a blend of Eudragit E100 and Eudragit NE; patch 2 based on Eudragit L100) were prepared. Both patches were equivalent in terms of coumarin release and ex vivo skin permeation profiles. The two patches differed significantly as regards respective adhesive properties. At low peel rate only patch 1 showed adhesive failure as confirmed by the in vivo performance. When comparing the behaviour of the patches containing melilot extract with analogous patches containing synthetic coumarin, no melilot phytocomplex enhancer effect was shown. The data of the ex vivo coumarin skin permeation and those obtained by the in vivo stripping technique showed a good correlation (r(2)=0.9727 for patch 1, r(2)=0.9835 for patch 2).
Collapse
|
56
|
Abstract
The positive association of a moderate intake of alcoholic beverages with a low risk for cardiovascular disease, in addition to ethanol itself, may be linked to their polyphenol content. This article describes the effect of acute ingestion of beer, dealcoholized beer, and ethanol (4.5% v/v) on the total plasma antioxidant status of subjects, and the change in the high performance liquid chromatography profile of some selected phenolic acids (caffeic, sinapic, syringic, and vanillic acids) in 14 healthy humans. Plasma was collected at various times: before (T0), 1 hour after (T1), and 2 hours after (T2) drinking. The study is part of a larger research planned to identify both the impact of brewing on minor components potentially present in beer and their metabolic fate in humans. Beer was able to induce a significant (P < 0.05) increase in plasma antioxidant capacity at T1 (mean +/- SD: T0 1,353 +/- 320 microM; T1 1,578 +/- 282 microM), returning close to basal values at T2. All phenolic acids measured in plasma tended to increase after beer intake (20% at T1, 40% at T2). Syringic and sinapic acid reached statistical significance (P < 0.05 by one-way analysis of variance-Fisher's test) at T1 and T2, respectively. Plasma metabolic parameters (glucose, total cholesterol, triglycerides, and uric acid) and plasma antioxidants (alpha-tocopherol and glutathione) remained unchanged. Ethanol removal impaired the absorption of phenolic acids, which did not change over the time of the experiment, accounting for the low (and not statistically significant) increase in plasma antioxidant capacity after dealcoholized beer drinking. Ethanol alone did not affect plasma antioxidant capacity or any of the antioxidant and metabolic parameters measured.
Collapse
|
57
|
Abstract
Nine binary mixtures of seven different methacrylic copolymer systems (Plastoid((R)) E 35 L (PLE) and Plastoid((R)) L 50 (PLL); Eudragit((R)) (Eu) NE, RL, RS, L, S) were tested as components of monolayer patches containing miconazole. Only three mixtures (PLE:EuNE, PLE:EuRL and PLE:EuRS) were suitable for the preparation of placebo matrices. Miconazole patches with good technological characteristics were obtained by using mixtures of PLE:EuNE and PLE:EuRL. The in vitro miconazole release rate from the two patches and from the patch prepared using only PLE were significantly different. The amounts of drug released in 24 h were quite satisfactory. A mathematical model based on capillary viscometry data was used for the evaluation of interactions between copolymers. This was useful to predict and understand the mechanisms related to the instability of the prepared mixture. The solubility parameters of the drug and of the matrix were also calculated. Miconazole release was faster when the difference between the solubility parameters of the matrix and of the drug was higher. A relationship between miconazole release rate and the difference of drug and matrix solubility parameters was found. Therefore, the solubility parameter could be applied in formulation studies of patches.
Collapse
|
58
|
|
59
|
Comparison of different membranes with cultures of keratinocytes from man for percutaneous absorption of nitroglycerine. J Pharm Pharmacol 1999; 51:673-8. [PMID: 10454043 DOI: 10.1211/0022357991772961] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The permeability barrier function of cell-culture membranes to the permeation of nitroglycerine was evaluated to find an alternative to skin from man for ex-vivo skin-permeation tests. The membranes were prepared, under submerged conditions, by inducing the growth of keratinocytes, from different donors, on a film of esterified jaluronic acid for different times (10, 20 and 30 days). Their permeability barrier functions were compared with those of some of the most widely used artificial membranes, silicone rubber (Silastic), cellulosic material (Cuprophan, Millipore HAWP), polysulphone membrane (Supor) and polytetrafluoroethylene membrane (TF-PTFE), and with those of biological membranes such as fresh and frozen skin, stratum corneum and epidermis from man, and hairless mouse skin. For each membrane the permeation profile was obtained and the flux was calculated. The permeation profiles for nitroglycerine were similar and linear in the first 2-3 h for all the synthetic membranes tested except TF-PTFE. For this membrane the profile was linear throughout the period considered and the amount permeating in 24 h (1603 microg cm(-2)) was significantly lower than those obtained for the other artificial membranes (between 1926 and 2508 microg cm(-2)). The amounts permeating through all the biological membranes in 24 h were in the range 520 to 781 microg cm(-2), except those for the keratinocyte-culture membranes, which were in the range 1730 to 2553 microg cm(-2). Prolonging the growth period of cultured keratinocytes did not affect nitroglycerine permeation. The findings suggest that these keratinocyte-culture membranes have some advantages--good reproducibility if obtained from the same donor; many membranes can be obtained from the same donor; the preparation is simple; they can be handled more easily than traditional cell-culture membranes; and they afford constant penetration rates for a longer period than synthetic membranes. The membranes could be used for preliminary in-vitro permeation studies.
Collapse
|
60
|
Dermal patches for the controlled release of miconazole: influence of the drug concentration on the technological characteristics. Drug Dev Ind Pharm 1999; 25:679-84. [PMID: 10219539 DOI: 10.1081/ddc-100102225] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The aim of this work was to evaluate the effect of different amounts of miconazole nitrate (MIC) on the technological characteristics (drug release profile, adhesiveness, and water vapor permeability) of a nonocclusive dermal therapeutic system (DTS) for the treatment of tinea unguium infection. Artificial silk was used as a backing layer. The self-adhesive matrix was made of a mixture of Plastoid E 35 L (PL L), an adhesive hydrophilic polymer, and Eudragit NE 40 D (EU NE), a nonadhesive hydrophobic polymer able to modify the drug release. Plastoid E 35 L is a copolymer of dimethylaminoethyl methacrylate and neutral methacrylic ester. Eudragit NE 40 D is a copolymer of ethylacrylate and methylmethacrylate. Formulations containing different amounts of MIC, ranging from 2% to 16% w/w of the dried matrix, were designed. Drug crystals were observed by polarizing light microscopy, proving the incomplete solubilization of MIC only in the matrices containing 8% w/w or more of this compound. All systems provided an in vitro control of drug release for at least 24 hr. The amount of the drug released increased with drug loading in all DTS. The percentage of the drug released was the same in all the DTS containing detectable crystals of MIC. When the MIC was completely dissolved in the matrix, the released percentage decreased when drug loading increased. The water vapor permeability and the adhesive properties of the DTS were excellent.
Collapse
|
61
|
Abstract
BACKGROUND Erythroblasts have been the most encouraging candidate cell type for noninvasive prenatal genetic investigation. We previously showed that human erythroblasts can be recovered from bone marrow and blood bank buffy coats by a physical cell separation. In the present study, we modified our previous methodology, taking into account the peculiar behavior of erythroblasts in response to modifications of pH and osmolality of the separation medium. METHODS Twenty to forty milliters of cord blood were initially centrifuged on Ficoll/diatrizoate (1.085 g/ml). The interphase cells were further separated on a continuous density gradient (1.040-1.085 g/ml). Two different gradients were initially compared: the first was iso-osmolar and neutral, whereas the second also contained an ionic strength gradient and a pH gradient (triple gradient). A subsequent monocyte depletion was performed by using magnetic microbeads coated with anti-CD14 monoclonal antibody (mAb), and erythroblasts were purified by sedimentation velocity. Purified cells were investigated by analyses with fluorescence-activated cell sorting (FACS) and fluorescence in situ hybridization (FISH) and immunocytochemistry with mAb against fetal hemoglobin and were cultured in vitro. RESULTS When nucleated cells were spun on an iso-osmolar and neutral continuous density gradient, two separated bands of nucleated red blood cells (NRBCs) were obtained: a light fraction banding at 1.062 g/ml and an heavy fraction banding at 1.078 g/ml. Conversely, when cells were spun in the triple gradient, NRBCs were shifted to the low-density region. Monocyte depletion by immunomagnetic microbeads and velocity sedimentation provided a pure erythroblast population. FACS and FISH analyses and immunocytochemistry substantiated the purity of the isolated cell fraction, which was successfully cultured in vitro. CONCLUSIONS We have shown that fetal erythroblasts can be purified up to homogeneity from cord blood, but further refinements of the isolation procedure are necessary before the same results can be obtained from maternal peripheral blood.
Collapse
|
62
|
[Transvaginal ultrasonic evaluation of the thickness of the section of the uterine wall in previous cesarean sections]. MINERVA GINECOLOGICA 1999; 51:107-12. [PMID: 10379144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
BACKGROUND The aim of this study is to evaluate accuracy of transvaginal sonographic examination of the lower uterine segment in pregnant women with previous cesarean section. METHODS Sixty-one pregnant women between 37 and 40 weeks of gestation, with previous cesarean section underwent transvaginal ultrasonography. Wall thickness of the lower uterine segment, the length of cervix, dilation of the isthmus uteri were measured. On the basis of the surgical findings (in 53 patients) and outcome of the trial of labor (in 8 patients) a Score was assigned to the pregnant women: Score 1 to the women who had good healing or a trial of labor without complications; Score 2 to the women with a thin or discontinued scar and in case of threatened rupture of the uterus in the trial of labor. RESULTS The mean thickness of the lower uterine segment is 3.82 mm +/- 0.99 mm. The Score 1 group shows a mean thickness of 4.2 mm +/- 2.5 mm, and the Score 2 group a mean thickness of 2.8 mm +/- 1.06 mm. The transvaginal sonographic examination provides a sensitivity and a specificity respectively of 100 and 75%, for a thickness cut-off of 3.5 mm, and a positive and negative predictive values of 60.7% and 100% respectively. CONCLUSIONS The transvaginal sonographic evaluation of the lower uterine segment improves therefore the obstetrical decision-making regarding the trial of labor in women with previous cesarean section.
Collapse
|
63
|
The cationic ring-opening polymerization of 7-tetradecene oxide with methyl trifluoromethansulfonate. An investigation of the mechanism and the kinetics by means of 1H, 13C and 19F NMR. POLYMER 1999. [DOI: 10.1016/s0032-3861(97)10005-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
64
|
[The effectiveness of gamma-irradiated products on microspheres of polylactide-co-glycolide containing bupivacaine]. BOLLETTINO CHIMICO FARMACEUTICO 1999; 138:91-8. [PMID: 10394706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
|
65
|
Abstract
Clinical trials have shown the potential of benzoxazinones, a new class of organic nitrates, in cardiovascular therapy. In particular Sinitrodil possesses a coronary vascular selectivity greater than that of Nitroglycerin and isosorbide dinitrate. The objective of this study was a preliminary evaluation of the ability of these new organic nitrate derivatives to reach therapeutical steady-state plasma concentrations following a transdermal administration. In vitro permeation studies through human stratum corneum and epidermis have been conducted on two members of this class: Sinitrodil (ITF 296) and ITF 1129. Comparative studies have also been carried out with Nitroglycerin, Isosorbide dinitrate and Nicorandil. Two different fixed concentrations were tested: 0.08% w/v solution and saturated solution. Sinitrodil could be considered a good candidate for transdermal administration on the basis of the in vitro permeation results and of the known therapeutical plasma concentration.
Collapse
|
66
|
Proton exchange and isomerisation reactions of photochromic and reverse photochromic spiro-pyrans and their merocyanine forms. Phys Chem Chem Phys 1999. [DOI: 10.1039/a902379h] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
67
|
Abstract
Adhesion is an essential property of the dermal and transdermal therapeutic systems (TS). It is influenced by the composition and the thickness of the matrix and also by the characteristics of the backing layer. Our aim was to evaluate the usefulness of the "thumb tack test," the "tack rolling ball test," and the "peel adhesion 180 degrees test" in the development studies and quality control of TS. These tests were performed on two series of placebo patches in which the backing layer was made of artificial silk (series 1) and polyurethane film (series 2). The patches of both series were prepared using five different mixtures of a hydrophilic adhesive copolymer and a hydrophobic nonadhesive copolymer as matrices. Plastoid E 35 L, a copolymer of dimethylaminoethyl methacrylate and neutral methacrylic esters, was used as the adhesive polymer. Eudragit NE 40 D, a copolymer of ethylacrylate and methylmethacrylate, was used as the nonadhesive copolymer. In the standard procedure for the peel adhesion 180 degrees test, used in the tape industries, the adherent is made of stainless steel. Because the latter has a high surface energy, it was not suitable for the analysis of the patches with a polyurethane backing layer. Therefore, the critical surface tension of five alternative materials (rubber, polysiloxane, polyethylene, nylon, polyvinyl chloride) was evaluated. Polyethylene was selected for the modified peel adhesion 180 degrees test, and better results were obtained in terms of feasibility of the test and ability to discriminate between the different patches prepared.
Collapse
|
68
|
|
69
|
Abstract
Gamma radiation treatment plays an increasingly important role in the sterilization/sanitization of pharmaceutical products. However, irradiation may affect the stability of the product and thus its safety of use. We investigated the influence of ionizing radiation on modified release microparticulate drug delivery systems made of two types of polylactide-co-glycolide copolymers (PLG): RG 503 and RG 503H; these polymers have identical molecular weights but different chemical structures. The effect of gamma radiation on polymer stability of the raw polymers (P) and related microspheres (Ms) was evaluated. Samples were irradiated at different irradiation doses (5, 15 and 25 kGy) using 60Co as radiation source. The microspheres were prepared using the spray drying technique. Degradation of PLG and related microspheres was evaluated during six months in terms of average molecular weight (Mw) loss by gel permeation chromatography (GPC) and variation in glass transition temperature (Tg) using differential calorimetry (DSC). The presence of free radicals in the product was tested by electron paramagnetic resonance (EPR). Both P and Ms showed a trend in decreasing their Mw at time 0 as a function of irradiation dose. For RG503 the decay in Mw is always negligible for doses below 15 kGy while it is about 10% for 25 kGy. After 150 days Mw decay was 25% in the microspheres and 20% in the raw polymer. It was not possible to evaluate the radiation effect, at different storage times, for RG503H because this polymer resulted to be unstable even in the regular storage conditions without being irradiated. The concentration of radiation-induced free radicals was higher in RG 503H (both P and Ms) and they were more stable than the free radicals species observed in the case of polymer RG 503. Alterations and/or production of new radicals were observed on exposure of RG 503H microspheres to the light. Radiolytic degradation of RG 503 under vacuum is characterized by a prevalence of the chain scission events leading to a decrease of Mw. Some crosslinking can occur mainly in the post irradiation stage through the decay and coupling of the hydrogen abstraction radicals. A hydroperoxydative cycle, whose mechanism is suggested, is generated in the presence of oxygen.
Collapse
|
70
|
Abstract
The work is aimed at the preparation and characterization of biodegradable microspheres of poly-D,L-lactide-co-glycolide (PLGA), for the controlled release of clonazepam. The solubility characteristics of this drug make it an interesting example to evaluate the performances of the two most widely used microencapsulation techniques, emulsification solvent evaporation and spray-drying. Several biodegradable PLGA copolymers have been evaluated (RG 502H, RG 503H, RG 503, Boerhinger Ingelheim). They differ in terms of molecular weight and physico-chemical characteristics. The microspheres obtained have been characterized for their morphology, physico-chemical properties (DSC) and in vitro dissolution behaviour. Between the two preparation methods, only spray-drying was suitable for the microencapsulation of clonazepam in PLGA microspheres. In vitro dissolution tests highlight that more sustained release of drug is achieved with the higher (molecular weight) polymer.
Collapse
|
71
|
Abstract
The relationship between chronic moderate beer consumption and oxidative stress was studied in rats. Animals were fed three different isocaloric diets for six weeks: a beer-containing diet (30% w/w), an ethanol-supplemented diet (1.1 g/100 g, the same as in the beer diet) and an alcohol-free basal diet. At the end of the feeding period, rats were analyzed for plasma and liver oxidative status. Some livers were isolated and exposed to ischemia-reperfusion to assess the additional oxidative stress determined by reperfusion. No significant differences in plasma antioxidant status were found among the three dietary groups. Lipoproteins from the beer group, however, showed a greater propensity to resist lipid peroxidation. Ischemia caused a decrease in liver energy and antioxidant status in all groups. Nevertheless, ATP was lower in the livers of rats exposed to the ethanol diet. During reperfusion, lipoperoxidation increased significantly in all groups. However, livers obtained from ethanol-treated rats showed the higher formation of lipoperoxides. In conclusion, a moderate consumption of beer in a well-balanced diet did not appear to cause oxidative stress in rats; moreover, probably through its minor components, beer could attenuate the oxidative action of ethanol by itself.
Collapse
|
72
|
|
73
|
Abstract
The aim of this work was to carry out a cost evaluation of the home care programme for terminally ill cancer patients run by the Istituto Oncologico Romagnolo (I.O.R.) in the areas of Forlì, Cesena, Ravenna and Rimini (Romagna, Italy). To determine effective home care direct costs, we first selected 1 week of care as an observation unit. We then proceeded to assess the medical and nursing care units together with the clinical protocols administered for each patient. The Karnofsky Performance Status (KPS) was also assessed weekly. In this way, we calculated care costs for each patient and for each week as the sum of medical costs, nursing costs, treatment costs and other costs. A consecutive series of 574 patients were involved in the study from 1 April 1994 to 31 March 1995. A total of 5164 patient-weeks of care was provided, with an average cost per week of 177.6 Ecu. This weekly cost increased in the last 100 days of life (week -15 = 179.5 Ecu; week -8 = 188.3 Ecu; week -2 = 221.0 Ecu; P < 0.001). When single components were analysed in relation to total cost (treatment protocols, physician and nursing care) the increased global cost was found to be mainly attributable to the intensification in nursing care (21.8% of costs in week -15 vs 27.3% of costs in week -2). Examination of the relation between the cost of 1 week of care and KPS values clearly shows that healthcare costs increased as KPS decreased (from 152.2 Ecu with KPS > or = 60 to 292.6 Ecu with KPS < or = 20; P < 0.001). Home care costs were also seen to vary with some clinical characteristics and symptoms present when patients entered the study: asthenia, anorexia, nausea/vomiting, bedsores. Given the good results of home care for cancer patients in terms of quality of life, this method of cost accounting for home-care providers can help to monitor the rising cost of assistance and confirm the cost effectiveness of this type of care.
Collapse
|
74
|
Buccoadhesive tablets for the slow delivery of cetylpyridinium chloride: design and in vitro/in vivo analysis. BOLLETTINO CHIMICO FARMACEUTICO 1997; 136:543-8. [PMID: 9432193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A buccoadhesive slow-release system constituted by a monolayer tablet was developed for the administration of cetylpyridinium chloride (CPC). Tablet composition was based on a mixture of a bioadhesive polymer with conventional excipients. Three different polymers (Methocel K4M, Noveon AA1, Carbopol 974P) in three different concentrations (10%, 20%, 30%) were used. The release profile and the adhesion properties of nine formulations were evaluated in vitro. Based on these results three formulations containing 10% w/w of the tested polymers were chosen to assess, with preliminary in vivo studies, the compliance and the residence time in the month of the systems. Tablets containing Noveon AA1 showed the best performances.
Collapse
|
75
|
Thermal and Photodegradation of Photochromic Spiroindolinenaphthooxazines and -pyrans: Reaction with Nucleophiles. Trapping of the Merocyanine Zwitterionic Form. J Am Chem Soc 1997. [DOI: 10.1021/ja961784c] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
76
|
Characterization of the biophysical properties of human erythroblasts as a preliminary step to the isolation of fetal erythroblasts from maternal peripheral blood for non invasive prenatal genetic investigation. Haematologica 1997; 82:5-10. [PMID: 9107075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND AND OBJECTIVE Fetal erythroblasts in maternal circulation represent a valuable source of fetal cell material which can be obtained with non-invasive procedures that do not endanger the fetus. Physical separation techniques have been invaluable in the isolation and characterization of different cells. There are basically two principles that have been used most successfully: separation according to density and separation according to size. In order to determine whether physical separation procedures are capable of purifying human erythroblasts, the biophysical characteristics of these cells were determined. METHODS Bone marrow particles were obtained from formal adults and peripheral blood buffy coats from blood banks. A single cell suspension was initially fractionated by buoyant density gradient centrifugation. Fractions enriched in erythroblasts were pooled and further processed by velocity sedimentation in order to take advantage of the differences in size of erythroblasts and other cells. RESULTS Density distribution curves were drawn after density gradient centrifugation for the different cell types present in the starting cell samples. Separation of the erythroblast-enriched density fractions by velocity sedimentation was successful and a highly purified population of erythroblasts was obtained. Cell size distribution of the different cell types was determined. INTERPRETATION AND CONCLUSIONS This initial study defines the biophysical properties (size and density) of human erythroblasts in bone marrow and peripheral blood and is a necessary preliminary step in setting up the optimal procedure for the isolation of fetal erythroblasts from maternal peripheral blood in sufficient amounts and purity for prenatal non-invasive genetic investigation.
Collapse
|
77
|
Abstract
In this paper the new procedures for the marketing authorisation are considered from the point of the view of their influence on the medicinal product presentation (labelling and package leaflet), dispensing and distribution. The legal status of some active ingredients in different countries as well as the situation in the Italian domestic market have been analysed. Even if the European directive is completely implemented, the harmonisation process appears difficult in consideration of the different social, political and economical characteristics of the different countries, and is going to cover many years.
Collapse
|
78
|
Development and characterisation of a dermal miconazole nitrate therapeutic system. Eur J Pharm Sci 1996. [DOI: 10.1016/s0928-0987(97)86452-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
79
|
Gamma irradiation effects of poly(D,L-lactide-co-glycolide) microspheres. Eur J Pharm Sci 1996. [DOI: 10.1016/s0928-0987(97)86395-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
80
|
Abstract
A study on the evolution with age of the mineral composition of bones was performed on samples belonging to human and other common mammalian species (cattle, sheep, dog). The study was carried out on the ashes obtained by calcination of the bone samples (1 h at 900 degrees C). The calcined powders were carefully examined by X-ray diffraction, from which precise quantitative evaluation (also confirmed by chemical analysis) of the crystalline phases present was derived. These data were analysed as a function of the introduced fractional age phi, a new relative scale that allows even largely different lifespan species to be compared. An overall linear increase in (Ca + Mg)/P ratio with log phi was found and the other considerations on molecular constitution (especially as regards Mg2+ substituting for Ca2+ in very young subjects) of the various phases detected were formulated and relative implications evaluated. The results appear promising for an improvement of knowledge in the field of biomedical experimentation and clinical implantology.
Collapse
|
81
|
Successful pregnancy following gonadotropin therapy in a young female with juvenile idiopathic hemochromatosis and secondary hypogonadotropic hypogonadism. Haematologica 1995; 80:335-7. [PMID: 7590503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Heart failure and hypogonadotropic hypogonadism are the most frequent clinical problems encountered in patients with juvenile idiopathic hemochromatosis (JIH). In this context, amenorrhea is one of the first symptoms in female patients, and hormone therapy must be added to phlebotomy to restore menstrual cycles. Here we report the case of a woman in childbearing age with hypogonadotropic hypogonadism due to JIH. Following therapy with gonadotropinic hormones the patient had a twin pregnancy with term delivery. The newborns presented a normal iron status. This confirms that early diagnosis and treatment of JIH are important to prevent irreversible organ damage and shows that the female reproductive function can be preserved in adequately treated patients.
Collapse
|
82
|
European community procedures for the marketing authorisation of medicinal products: impact on presentation and distribution. Pharmacol Res 1995. [DOI: 10.1016/1043-6618(95)87777-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
83
|
|
84
|
|
85
|
Precocious signs of polycystic ovaries in obese girls. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 1994; 4:310-315. [PMID: 12797166 DOI: 10.1046/j.1469-0705.1994.04040310.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
As several studies have reported that 35% of patients with polycystic ovary syndrome are obese and that this syndrome seems to originate during the early phase of sexual maturation, we undertook a study of such subjects. We studied ultrasound and hormonal findings in 49 obese girls aged from 7.9 to 19.10 years, with a mean excess weight of 44%; 23 premenarcheal girls and 26 postmenarcheal girls with mean gynecological age of 2.5 years. As controls, we studied 18 girls in the pubertal phase and 17 healthy girls with regular menses, matched for age and gynecological age. Pelvic ultrasonography was carried out in all girls and estrone, estradiol, progesterone, prolactin, follicle stimulating hormone, luteinizing hormone, sex hormone binding globulin (SHBG), testosterone, free testosterone, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEA-S), androstenedione and 17-hydroxyprogesterone (17-OHP) were measured by radioimmunoassay in 11 of the 18 postmenarcheal girls. Five girls (10.2%) with excess weight of > 40% presented with mild or severe hirsutism based on Ferriman and Gallway scores; six (12.2%) presented with acne and 14 (28.5%) presented with acanthosis nigricans.Hormonal evaluation showed elevated levels of estrone (p < 0.005) and testosterone (p < 0.01) but lower than normal levels of SHBG (p < 0.05) and estradiol (p <0.05). On the basis of our results, 23%) of the postmenarcheal obese subjects showed clinical, hormonal and ultrasonographic signs of polycystic ovaries, and 23% of postmenarcheal obese girls showed multifollicular ovaries. Six of these, at 1 year after menarche, showed a uterine cross-sectional area larger than normal for gynecological age (21.92 +/- 5.64 cm(2) vs. 16.36 +/- 2.34 cm(2)). Further serial echographic studies and a careful follow-up will demonstrate if both multifollicular ovaries and increased uterine cross-sectional area in obese girls are precocious signs of polycystic ovaries.
Collapse
|
86
|
Evaluation of the influence of open and closed-ampoule technologies on particulate matter in small-volume parenterals. JOURNAL OF PARENTERAL SCIENCE AND TECHNOLOGY : A PUBLICATION OF THE PARENTERAL DRUG ASSOCIATION 1993; 47:265-9. [PMID: 8263664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
SVP in glass ampoules are manufactured using two main different technological production processes: the open-ampoule process (O) and the closed-ampoule process (C). In principle, the open-ampoule production technology should lead to better controlled production process. To test this hypothesis and quantify the possible qualitative differences in the manufactured ampoules, a suitable experimental design was set up. The two ampoule production processes have been compared on the basis of the visible particulate burden. Two batches of ampoules filled with water for injections were produced for each type of process, following conventional industrial procedures. Two samples of 20,000 units were taken from each batch and inspected with different automatic inspection systems: two Brevetti CEA machines (S1, S2--light scattering) and two EISAI machines (S3, S4--light absorbtion). The comparison between the processes was based on the rejection percentage. On both inspection machines the open-ampoule production samples present rejection percentages (ranging from 0.154% to 1.248% rejection percentages) which, on average, are lower than those detected in closed-ampoule production (ranging from 1.434% to 3.86% rejection percentages). The difference between the two processes is even more marked if we also consider the data obtained using inspection machines S3 and S4. The substantial differences in performance of the four inspection machines stress the need to provide for adequate validation procedures.
Collapse
|
87
|
Synthesis and characterization of a potassium borosilicate with ANA framework type structure. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/0927-6513(93)80004-e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
88
|
Evaluation of hypercholesterol diet-induced changes in viscoelastic properties of carotid circulation in pigs. THE AMERICAN JOURNAL OF PHYSIOLOGY 1992; 263:H1919-26. [PMID: 1481915 DOI: 10.1152/ajpheart.1992.263.6.h1919] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Measurements of pulsatile pressure and flow at the input of the left and right carotid arteries and a new lumped parameter model were used to quantify changes in the overall dynamic mechanical properties of the carotid circulation between five control diet-fed pigs and five pigs fed a hyperlipidemic diet for 16 wk. The model represents the portion of the circulation supplied by either the left or the right carotid artery and is characterized by five parameters: peripheral resistance (Rp), an overall inertance (L), and an overall frequency-dependent compliance constituted by a capacitor C (static compliance) in series with a Maxwell section, i.e., a capacitor Cd, in parallel with a resistor Rd. Rp was calculated as the ratio between mean pressure (P) and mean flow (Q). The other four parameters were estimated by fitting measured to model predicted flows. The average static compliance was reduced by 40% (P = 0.01) between normal (P = 62.0 +/- 4.3 mmHg) and hyperlipidemic diet-fed pigs (P = 62.7 +/- 4.7 mmHg). A significant reduction in the overall cross-sectional area was inferred from a 53% increase (P = 0.05) in L, whereas resistance vessel tone was unchanged as judged from estimates of Rp. No signs of occlusive disease were found in any of the animals.
Collapse
|
89
|
Differences in blood pressure regulation of congestive heart failure, before and after treatment, correlate with changes in the circulating pattern of atrial natriuretic peptide. Eur Heart J 1992; 13:990-6. [PMID: 1386572 DOI: 10.1093/oxfordjournals.eurheartj.a060305] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The mechanisms underlying altered BP regulation in congestive heart failure are unknown. This study examines the possibility that differences in circadian blood pressure (BP) regulation between the normal and the failing heart correlate with changes in the circulating pattern of atrial natriuretic peptide (ANP). Twelve normotensive patients with coronary artery disease were studied over two separate 24-h periods, the first during acute exacerbation of congestive heart failure (radionuclide-determined ejection fraction at rest was less than 30%) and the second after therapy-induced functional recovery (ejection fraction was more than 40%). BP monitoring at 10-min intervals and intra-atrial blood samples for ANP assays at hourly intervals were obtained. Significant correlation between ejection fraction and the indexes of circadian BP variability (standard deviation of the 24-h pressure mean and day-night pressure difference) were found both before and after treatment. Ejection fraction was independent of the BP means (24-h, daytime and night-time). BP variability, 24-h mean and daytime mean were higher after treatment. ANP means were lower after treatment, whereas ANP variability was higher. The indexes of BP and ANP variability correlated both before and after treatment, whereas the BP and the ANP means were independent. These findings demonstrate that differences in BP regulation of CHF before and after effective treatment correlate with changes in the circulating pattern of ANP. We speculate that by modulating ANP release, the heart could be actively involved in BP regulation as part of the compensatory mechanisms aimed at protecting against circulatory overload.
Collapse
|
90
|
A gas-chromatographic determination of the ppb levels of volatile halogenated hydrocarbons in water for injections. BOLLETTINO CHIMICO FARMACEUTICO 1992; 131:193-8. [PMID: 1445685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Some volatile halogenated hydrocarbons have been found in commercial large volume parenterals (LVPs) prepared from untreated or treated (disinfected) water. To monitor the presence of volatile halogenated hydrocarbons in the source water and also in the water for injections, a low cost and sufficiently simple procedure has been developed, specifically for the following components: 1,1,1 trichloroethane, 1,1,2 trichloroethylene, 1,1,2,2 tetrachloroethylene, carbon tetrachloride, chloroform, dichlorobromomethane and dibromochloromethane. A Head-space technique coupled with ECD-gaschromatography was used. The procedure is thoroughly discussed in the article, including the results of a ring test for a preliminary validation of this method.
Collapse
|
91
|
91222601 Plasma levels of atrial natriuretic peptide are increased in normotensive postmenopausal women as a function of age. Maturitas 1992. [DOI: 10.1016/0378-5122(92)90123-l] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
92
|
Loss of nocturnal increase in plasma concentration of atrial natriuretic peptide in hypertensive chronic renal failure. Cardiology 1992; 80:312-23. [PMID: 1451118 DOI: 10.1159/000175020] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Diurnal change of plasma atrial natriuretic peptide (ANP) concentration was investigated in 12 patients with hypertension due to chronic renal failure (CRF) and in 12 patients with essential hypertension (EH) of comparable degree. Blood pressure (BP) monitoring was performed at 15-min intervals, while peripheral blood samples were obtained at 4-hour intervals starting from 8.00 h. The mean 24-hour plasma levels (+/- SEM) of ANP were 24.3 +/- 1.8 pmol/l in EH and 23.4 +/- 1.2 pmol/l in CRF. In EH, plasma ANP concentration was highest at 4.00 h (33.5 +/- 0.8 pmol/l) and lowest at 16.00 h (15.5 +/- 0.6 pmol/l). In CRF, no significant circadian change was present (22.2 +/- 3.1 and 20.4 +/- 3.6 pmol/l, respectively), and the nocturnal fall in BP was lost. Our data demonstrate that in CRF the loss and possible reversal of the nocturnal decline in BP is associated with the disappearance of any significant circadian variation in the circulating concentrations of ANP. These findings suggest a role for ANP in the alteration of BP variability of CRF, possibly mediated by autonomic dysfunction, and are further evidence for the existence of a relation between the circadian rhythms of ANP and BP.
Collapse
|
93
|
Evaluation of factors influencing ampoule secondary particulate contamination. A strategy for its reduction in small volume parenterals. BOLLETTINO CHIMICO FARMACEUTICO 1991; 130:323-8. [PMID: 1801862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In this paper, we evaluated the influence of some glass ampoules characteristics that are critical as far as secondary particle contamination (visible and sub-visible) of small volume parenterals. Following characteristics were considered: snap-opening system (colour-break scoring and o.p.c.); break-point strength (high and low); dimensional characteristics (three types D1, D2, D3). According to the proper statistical design, 18 different batches of 2 ml ampoules filled with water for injection were manufactured; then sub-visible and visible particulate contamination generated on snap-opening the ampoules were examined. Sub visible particle counting was performed by the light-blockage method and visible particles counting by the membrane-filtration method. With regard to sub-visible particles, statistical analysis showed significant interactions of break-point strength with both ampoule dimensional characteristics and the type of snap-opening system. Break-point strength seems to have the greatest influence on the level of particulate contamination. Differences in ampoule snap-opening systems and dimensional characteristics exert a significant effect on the level of particle contamination only at high break-point strength. With regard to visible particles generated on snapping the ampoules, data are consistent with the findings of sub-visible particulate contamination. Ampoules manufactured according to DIN dimensional characteristics and with an o.p.c. snap-opening system provide the lowest particle burden.
Collapse
|
94
|
Plasma levels of atrial natriuretic peptide are increased in normotensive postmenopausal women as a function of age. Cardiology 1991; 78:317-22. [PMID: 1832331 DOI: 10.1159/000174811] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The aim of this study was to assess the changes in atrial natriuretic peptide (ANP) levels before and after menopause and to test whether they depend on age or are an integral part of the hormonal changes in menopause. We measured plasma ANP, plasma renin activity (PRA), plasma aldosterone, serum estradiol-17 beta and progesterone concentrations in 103 normotensive women, either in premenopause (n = 35; mean age: 24 years), in physiological menopause (n = 34; mean age: 43 years) or surgically induced menopause (n = 34; mean age: 55 years). The last two groups were matched for duration of menopause and were comparable in their estrogen and progesterone status. PRA and plasma aldosterone concentrations decreased in postmenopausal women, whereas systolic blood pressure and ANP increased. These results were not confirmed after adjustment for age by covariance analysis. In all of the groups, plasma ANP concentrations were not significantly correlated with systolic or diastolic blood pressure, nor with plasma aldosterone, estrogen and progesterone concentrations. These correlations were not improved by correction for age. Plasma ANP concentrations were consistently correlated with age. These data suggest that the increase in plasma ANP levels found in postmenopausal women is related with age and that ANP does not play a direct role in the physiological hormonal changes of menopause.
Collapse
|
95
|
Consistent changes in the circadian rhythms of blood pressure and atrial natriuretic peptide in congestive heart failure. Chronobiol Int 1991; 8:432-9. [PMID: 1840179 DOI: 10.3109/07420529109059178] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We demonstrated in previous works that the circadian rhythms of blood pressure (BP) and atrial natriuretic peptide (ANP) are antiphasic in normal subjects and in essential hypertension. The aim of the present study was to assess the circadian rhythms of BP and ANP in 20 patients with stable congestive heart failure (CHF), divided into two groups of 10 according to their New York Heart Association functional class. A matched control group of 10 normal volunteers was also studied. Noninvasive BP monitoring at 15-min intervals was performed for 24 h. Peripheral blood samples were also obtained at 4-h intervals starting from 08:00 h. The mean (+/- SEM) circadian mesors of ANP plasma levels were 13.4 +/- 1.7 pmol/L in the control group, 28.6 +/- 2.4 pmol/L in the group of 10 patients in class II, and 81.5 +/- 12 pmol/L in the group of 10 patients in class III-IV. In normal subjects, plasma ANP concentration was highest at 04:00 h (21.5 +/- 2.7 pmol/L) and lowest at 16:00 h (8.8 +/- 2.4 pmol/L; p less than 0.01). Both groups of patients with CHF showed no significant circadian change in the plasma levels of ANP and also a significantly blunted circadian rhythm of BP. Cosinor analysis confirmed the loss of the circadian rhythms of ANP and BP in CHF patients. Our findings support the existence of a causal relationship between the circadian rhythms of ANP and BP.
Collapse
|
96
|
Loss of nocturnal decline of blood pressure in hypertension due to chronic renal failure. Am J Hypertens 1991; 4:20-6. [PMID: 2006993 DOI: 10.1093/ajh/4.1.20] [Citation(s) in RCA: 133] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The aim of this study was to assess the blood pressure profile of chronic renal failure in comparison with essential hypertension. Thirty hypertensive patients with chronic renal failure due to non-vascular nephropathies were matched by age, sex, and mean 24 h blood pressure, with 30 patients affected by uncomplicated mild-to-moderate essential hypertension. They were studied in an open hospital ward. Diet, meal times, sleep times, and activity schedules were standardized. Noninvasive, automatic, blood pressure recordings were performed for 48 h at sampling intervals of 15 min. The mean 24 h blood pressure almost coincided in the two groups. However, in essential hypertension a mean (+/- SD) nocturnal fall of systolic and diastolic blood pressure was found (12.7 +/- 3.8 and 12.9 +/- 4.8 mm Hg, respectively), while renal patients displayed an average nocturnal increase of 2.7 +/- 8.9 mm Hg and 3.7 +/- 7.8 (P less than .001). The renal patients had also higher heart rates, with a significantly blunted nocturnal fall (4.4 +/- 4.5 beats/min as compared to 9.3 +/- 3.1 beats/min of essential hypertension; P less than .001). Among the renal patients, the day-night blood pressure changes showed no significant correlation with age, creatinine clearance, hematocrit, nocturnal change in heart rate, or day or night mean blood pressure levels. These data suggest that an abnormal day-night pattern of blood pressure is present in chronic renal failure patients independently from external interfering factors. Hence, casual measurements of blood pressure confined to daytime may underestimate a hypertensive condition associated with chronic renal failure.
Collapse
|
97
|
Abstract
We studied the response of atrial natriuretic peptide to the hemodynamic and renin-aldosterone variations occurring in four patients who developed cardiac tamponade, either occurring in idiopathic fashion in one or secondary to metastatic involvement of the pericardium in three. Right atrial pressure, heart rate and arterial blood pressure were monitored and serial blood samples were taken before and over three hours after pericardiocentesis. During cardiac tamponade, normal levels of atrial natriuretic peptide (mean +/- SEM: 54 +/- 7.4 pg/ml) were observed in the plasma despite increased right atrial pressure (23 +/- 3.8 cm H2O) and heart rates (98 +/- 4.4). Removal of pericardial fluid (540 to 1160 ml) was associated at first with a 200% increase in plasma concentrations of atrial natriuretic peptide (108 +/- 8.8 pg/ml; P less than 0.001), then with a gradual decline toward normal levels, simultaneous with the normalization of right atrial pressure and heart rate. Activity of renin and concentrations of aldosterone in the plasma were increased during tamponade and returned gradually to normal after pericardiocentesis (3.8 +/- 0.9 to 1.2 +/- 0.3 ng/ml/h and 20 +/- 4.2 to 9 +/- 3.2 ng/dl, respectively; P less than 0.01). These data confirm that atrial strain, not intracavitary pressure in itself nor heart rate, is the main determinant of the acute release of atrial natriuretic peptide, which is associated with a suppressing effect on the renin-aldosterone system. In addition, our data indicate that secretion of atrial natriuretic peptide during cardiac tamponade is not stimulated by secondary hyperaldosteronism.
Collapse
|
98
|
99mTc-MAG3 versus 131I-orthoiodohippurate in the routine determination of effective renal plasma flow. THE JOURNAL OF NUCLEAR MEDICINE AND ALLIED SCIENCES 1990; 34:67-70. [PMID: 2147211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
99mTc-mercaptoacetyltriglycine (MAG3) has been proposed as an alternative to 131I-orthoiodohippurate (OIH) for the scintigraphic determination of effective renal plasma flow (ERPF). The purpose of this study was to compare the ERPF values determined simultaneously with MAG3 and OIH by a dual channel technique in a large group of subjects with widely ranging renal function. During the last two years, we administered a simultaneous injection of 74 MBq of MAG3 and 0.74 MBq of OIH to each subject who underwent a renal scintigraphic study in our hospital. They were 53 females and 50 males (mean age: 52 years; range: 18-70 years), either normal (30) or with a diagnosis of essential hypertension (53), chronic renal failure (14), renal calculi (5), or renal transplant (1). Plasma clearance and ERPF were calculated with both radiocompounds by using the exponential formula of Tauxe and coworkers and a single plasma concentration determination sampled 44 min after injection of the two tracers. The time-activity curves for kidney and blood were of the same bi-exponential type. The mean ratio between the two plasma clearances was 0.49. The linear regression of the ERPF values obtained with the two radiocompounds was highly significant (r = 0.69; p less than 0.0001) and is expressed by the equation: ERPF (MAG3) = 0.453 ERPF (OIH) + 25.7. These data suggest that the routine calculation of ERPF from MAG3 clearance is consistent with the results obtained from OIH clearance. In conclusion, MAG3 appears to be a good predictor of ERPF in routine clinical practice.
Collapse
|
99
|
Time-resolved optical emission and epr of the diphenylacetylene tetracyanobenzene crystal doped with t-stilbene. Chem Phys 1990. [DOI: 10.1016/0301-0104(90)89071-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
100
|
Circadian rhythms of atrial natriuretic peptide, renin, aldosterone, cortisol, blood pressure and heart rate in normal and hypertensive subjects. J Hypertens 1990; 8:85-95. [PMID: 2157761 DOI: 10.1097/00004872-199001000-00013] [Citation(s) in RCA: 92] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The occurrence and extent of a circadian rhythm in the circulating concentrations of atrial natriuretic peptide (ANP) are still matters of controversy. Only a few data are available in humans relating the time structure of plasma ANP levels with the circadian patterns of other hormones and cardiovascular variables. In a group of hospitalized normal volunteers (six men and four women, 16-76 years old), and in a group of hospitalized hypertensives (seven men and three women, 18-76 years old), we investigated the circadian variability of ANP and its temporal relationship with the circadian rhythms of blood pressure (BP) and heart rate (HR), and plasma renin activity (PRA), plasma aldosterone (PA) and plasma cortisol (PC) levels, by using a chronobiological inferential statistic method. At the end of a synchronizing period of 1 week (the diet and daily schedule were standardized), the subjects underwent automatic BP and HR monitoring, and blood sampling for 24 h. A statistically significant mean circadian rhythm was demonstrated for ANP, BP, HR, PRA, PA and PC in both normal and hypertensive subjects. The mean circadian acrophase of ANP (calculated to occur at around 04.00 h) anticipated the corresponding acrophases of the other hormones; BP and HR rhythms appeared to be in antiphase with ANP rhythm, i.e. the peak of BP and HR rhythms more or less coincided with the trough in ANP rhythm. A significant increase in the daily levels (assessed by the circadian mesor) of ANP was present in hypertensive subjects when compared with normal controls. In essential hypertension the circadian rhythm of ANP was set at higher circulating levels, but otherwise it was similar to the circadian rhythm found in normals. ANP mesors correlated significantly with renin and aldosterone mesors in normal subjects but not in hypertensive patients. ANP appears to anticipate awakening in its circadian periodic rise. On the basis of the considerable acrophase asynchronism, it seems possible to exclude any causal relations between the periodic changes of ANP and the rhythmic fluctuations of the other hormones that we studied. In contrast, important relations may be hypothesized between ANP levels and BP and HR values, on the basis of their antiphase rhythms.
Collapse
|