Cyst fluid antibiotic concentrations in polycystic kidney disease: Differences between proximal and distal cysts

Cyst fluid antibiotic concentrations in polycystic kidney disease: Differences between proximal and distal cysts. The concentrations of several antibiotics were measured in the cyst fluid of six adult patients with polycystic kidney disease Seventy-nine cysts were aspirated at surgery or autopsy Sixty-one cysts could be categorized as arising from the proximal nephron and 16 from the distal nephron by cyst fluid to serum sodium ratios. Serum, urine, and cyst fluid were simultaneously analyzed for sodium, creatinine, and various antibiotics. Gentamicin, tobramycin, cephapirin, and ticarcillin were either undetectable or present in low concentrations in renal cysts. Cyst fluid antibiotic concentrations did not correlate with cyst volume or creatinine clearance. Cysts of proximal nephron origin had higher antibiotic concentrations than distal cysts. In one patient with normal renal function, inulin was undetectable in renal cysts after a continuous 36-hour i.v. infusion. Para-aminohippurate, however, was detected in the renal cysts of this patient. These data help explain the poor clinical response of infected renal cysts to antibiotic therapy. They also suggest that antibiotics and other solutes may enter cyst fluid across tubular cells in addition to entry by glomerular filtration.Concentration intra kystique d'antibiotiques dans la maladie poly kystique rénale: Différences entre les kystes proximaux et distaux. Les concentrations de plusieurs antibiotiques dans le liquide des kystes ont été mesurées chez six sujets adultes atteints de maladie polykystique. Soixante dix neuf kystes ont été ponctionnés pendant des interventions chirurgicales ou des autopsies. Soixante et un kystes ont pu être classés comme proximaux et seize comme distaux en fonction du rapport de concentration de sodium kyste/plasma. Des déterminations de concentration de sodium, de creatinine et de divers antibiotiques ont été réalisées simultanément pour le plasma, l'urine et le liquide des kystes. La gentamicine, la tobramycine, la cephapirine et la ticarcilline étaient soit non détectables soit à des concentrations très faibles dans les kystes. Les concentrations d'antibiotiques dans les kystes n'étaient pas corrélées avec le volume du kyste ou la clearance de la creatinine. Les kystes proximaux avaient des concentrations d'antibiotiques plus élevées que les kystes distaux. Chez un malade dont la fonction rénale était normale l'inuline n'était pas détectable dans les kystes après une perfusion continue de 36 heures. Le para-aminohippurate, cependant, a été détecté dans les mêmes kystes. Ces résultats permettent de comprendre la réponse clinique faible des kystes infectés au traitement antibiotique. Ils suggèrent aussi que les antibiotiques ainsi que d'autres substances dissoutes peuvent pénétrer dans les kystes à travers les cellules tubulaires en sus de la pénétration par filtration glomérulaire

On the Analytic Structure of the Quark Self-Energy in Nambu-Jona- Lasinio Models

The self-energy of quarks is investigated for various models which are inspired by the Nambu--Jona-Lasinio (NJL) model. Including, beyond the Hartree-Fock approximation, terms up to second-order in the quark interaction, the real and imaginary parts of scalar and vector components of the self-energy are discussed. The second-order contributions depend on the energy and momentum of the quark under consideration. This leads to solutions of the Dirac equation which are significantly different from those of a free quark or a quark with constant effective mass, as obtained in the Hartree-Fock approximation.Comment: 15 pages LaTeX, 6 figures can be obtained from author

Two tricritical lines from a Ginzburg-Landau expansion: application to the LOFF phase

We study the behavior of the two plane waves configuration in the LOFF phase close to T=0. The study is performed by using a Landau-Ginzburg expansion up to the eighth order in the gap. The general study of the corresponding grand potential shows, under the assumption that the eighth term in the expansion is strictly positive, the existence of two tricritical lines. This allows to understand the existence of a second tricritical point for two antipodal plane waves in the LOFF phase and justifies why the transition becomes second order at zero temperature. The general analysis done in this paper can be applied to other cases.Comment: LaTex file, 15 pages, 6 figure

Medication-related problem type and appearance rate in ambulatory hemodialysis patients

Abstract Background Hemodialysis (HD) patients are at risk for medication-related problems (MRP). The MRP number, type, and appearance rate over time in ambulatory HD patients has not been investigated. Methods Randomly selected HD patients were enrolled to receive monthly pharmaceutical care visits. At each visit, MRP were identified through review of the patient chart, electronic medical record, patient interview, and communications with other healthcare disciplines. All MRP were categorized by type and medication class. MRP appearance rate was determined as the number of MRP identified per month/number of months in study. The number of MRP per patient-drug exposures were determined using: {[(number of patients) × (mean number of medications)]/(number of months of study)} /number of MRP identified. Results were expressed as mean ± standard deviation or percentages. Results Patients were 62.6 ± 15.9 years old, had 6.4 ± 2.0 comorbid conditions, were taking 12.5 ± 4.2 medications, and 15.7 ± 7.2 doses per day at baseline. Medication-dosing problems (33.5%), adverse drug reactions (20.7%), and an indication that was not currently being treated (13.5%) were the most common MRP. 5,373 medication orders were reviewed and a MRP was identified every 15.2 medication exposures. Overall MRP appearance rate was 0.68 ± 0.46 per patient per month. Conclusion MRP continue to occur at a high rate in ambulatory HD patients. Healthcare providers taking care of HD patients should be aware of this problem and efforts to avoid or resolve MRP should be undertaken at all HD clinics.Peer Reviewe

Chiral dynamics and the growth of the nucleon's gluonic transverse size at small x

We study the distribution of gluons in transverse space in the nucleon at moderately small x (~10^{-2}). At large transverse distances (impact parameters) the gluon density is generated by the 'pion cloud' of the nucleon, and can be calculated in terms of the gluon density in the pion. We investigate the large-distance behavior in two different approaches to chiral dynamics: i) phenomenological soft-pion exchange, ii) the large-N_c picture of the nucleon as a classical soliton of the pion field, which corresponds to degenerate N and Delta states. The large-distance contributions from the 'pion cloud' cause a \~20% increase in the overall transverse size of the nucleon if x drops significantly below M_pi/M_N. This is in qualitative agreement with the observed increase of the slope of the t-dependence of the J/psi photoproduction cross section at HERA compared to fixed-target energies. We argue that the glue in the pion cloud could be probed directly in hard electroproduction processes accompanied by 'pion knockout', gamma^* + N -> gamma (or rho, J/psi) + pi + N', where the transverse momentum of the emitted pion is large while that of the outgoing nucleon is restricted to values of order M_pi.Comment: 20 pages, revtex4, 10 eps figure

Realistic Model of the Nucleon Spectral Function in Few- and Many- Nucleon Systems

By analysing the high momentum features of the nucleon momentum distribution in light and complex nuclei, it is argued that the basic two-nucleon configurations generating the structure of the nucleon Spectral Function at high values of the nucleon momentum and removal energy, can be properly described by a factorised ansatz for the nuclear wave function, which leads to a nucleon Spectral Function in the form of a convolution integral involving the momentum distributions describing the relative and center-of-mass motion of a correlated nucleon-nucleon pair embedded in the medium. The Spectral Functions of $^3He$ and infinite nuclear matter resulting from the convolution formula and from many-body calculations are compared, and a very good agreement in a wide range of values of nucleon momentum and removal energy is found. Applications of the model to the analysis of inclusive and exclusive processes are presented, illustrating those features of the cross section which are sensitive to that part of the Spectral Function which is governed by short-range and tensor nucleon-nucleon correlations.Comment: 40 pages Latex , 16 ps figures available from the above e-mail address or from [email protected]

Inhomogeneous Superconductivity in Condensed Matter and QCD

Inhomogeneous superconductivity arises when the species participating in the pairing phenomenon have different Fermi surfaces with a large enough separation. In these conditions it could be more favorable for each of the pairing fermions to stay close to its Fermi surface and, differently from the usual BCS state, for the Cooper pair to have a non zero total momentum. For this reason in this state the gap varies in space, the ground state is inhomogeneous and a crystalline structure might be formed. This situation was considered for the first time by Fulde, Ferrell, Larkin and Ovchinnikov, and the corresponding state is called LOFF. The spontaneous breaking of the space symmetries in the vacuum state is a characteristic feature of this phase and is associated to the presence of long wave-length excitations of zero mass. The situation described here is of interest both in solid state and in elementary particle physics, in particular in Quantum Chromo-Dynamics at high density and small temperature. In this review we present the theoretical approach to the LOFF state and its phenomenological applications using the language of the effective field theories.Comment: RevTex, 83 pages, 26 figures. Submitted to Review of Modern Physic

Pairing in nuclear systems: from neutron stars to finite nuclei

We discuss several pairing-related phenomena in nuclear systems, ranging from superfluidity in neutron stars to the gradual breaking of pairs in finite nuclei. We focus on the links between many-body pairing as it evolves from the underlying nucleon-nucleon interaction and the eventual experimental and theoretical manifestations of superfluidity in infinite nuclear matter and of pairing in finite nuclei. We analyse the nature of pair correlations in nuclei and their potential impact on nuclear structure experiments. We also describe recent experimental evidence that points to a relation between pairing and phase transitions (or transformations) in finite nuclear systems. Finally, we discuss recent investigations of ground-state properties of random two-body interactions where pairing plays little role although the interactions yield interesting nuclear properties such as 0+ ground states in even-even nuclei.Comment: 74 pages, 33 figs, uses revtex4. Submitted to Reviews of Modern Physic