Ventilation imaging of the lung: Comparison of hyperpolarized helium-3 MR imaging with Xe-133 scintigraphy

RATIONALE AND OBJECTIVES: To compare hyperpolarized helium-3 (HHe) magnetic resonance imaging (MRI) of the lung with standard Xe-133 lung ventilation scintigraphy. MATERIALS AND METHODS: We performed a retrospective review of 15 subjects who underwent HHe MRI and Xe-133 lung ventilation imaging. Coronal MRI sections were acquired after a single inhalation of HHe gas, and standard posterior planar lung ventilation scintigraphy was performed during continuous breathing of Xe-133 gas. The first breath scintigram of each patient was compared with a composite MR image composed of the sum of the individual MR images and with the individual helium-3 MR images. Ventilation defects on the two imaging modalities were compared for size, conspicuity, and concordance in presence and location. Assessment was done separately for each of four lung quadrants. RESULTS: Comparing the composite HHe MR images with Xe-133 scintigraphy, ventilation defect size, conspicuity and concordance were the same in 67% (40/60), 63% (38/60), and 62% (37/60) quadrants, respectively. Comparing the individual HHe MR image sections with the Xe-133 ventilation scan, there was concordance between the ventilation defects in 27% (16/60) of quadrants. More defects were identified on the individual HHe MR images in 62% (37/60) of quadrants. CONCLUSION: There was good agreement between composite HHe MR image and first breath Xe-133 scintigraphic images, supporting the widely held assumption that HHe MRI likely depicts first breath lung ventilation.     

Chronic cyclosporine nephrotoxicity in renal transplantation

Although extensively studied, the pathophysiologic characteristics of chronic cyclosporine (CsA) nephrotoxicity are still far from being completely understood. The recognition of chronic CsA nephrotoxicity in allografted kidneys is hampered by a lack of easily assessable sensitive and specific markers. Long-term results of CsA withdrawal trials and trials that evaluated CsA sparing or withdrawal after the diagnosis of chronic allograft nephropathy (CAN) have shown that chronic CsA nephrotoxicity has a more important role in the etiology of late transplant dysfunction than appreciated before. Various hypotheses have explained the renal structural changes of chronic CsA nephrotoxicity including ischemia, cellular toxicity, and the stimulation of renal fibrosis by growth factors or cytokines. Possible ways to prevent chronic CsA nephrotoxicity include improved therapeutic drug monitoring and CsA withdrawal or avoidance. Patients with aspecific CAN in late biopsy may benefit from withdrawal of CsA or a reduction of its dose. Current knowledge is being discussed. It is concluded that in the near future more strategies are likely to be used to prevent loss of allograft function as a result of drug toxicity.     

Combined evaluation of first pass radionuclide angiography and equilibrium radionuclide ventriculography in the diagnosis of coronary artery disease

Results of 203 patients who underwent first pass radionuclide angiography (FP) and quantitative equilibrium radionuclide ventriculography (qERNV) were stored in a data base system and evaluated statistically. Eighty eight of these patients also underwent exercise equilibrium radionuclide ventriculography (E-qERNV). In patients with coronary artery disease (CAD) without previous myocardial infarction (MI), evaluation of global and regional ejection fraction (gEF, rEF) at rest revealed a poor sensitivity of 64%, the specificity was about 71% (qERNV). FP at rest revealed similar values of sensitivity (69%) and specificity (83%). Additional assessment of stress induced changes of gEF, significantly (P<0.05) improved sensitivity of qERNV in CAD patients without a history of previous MI to 84% (specificity 86%). In patients with one previous MI, however, similar values of sensitivity were found (RFP: 87%, R-qERNV: 84%, E-qERNV: 93%). In patients with several MI's, sensitivity was above 90% at rest and during exercise (R-FP: 96%, R-qERNV: 93%, E-qERNV: 100%).     

Lindane inhibition of [35S]TBPS binding to the GABAA receptor in rat brain.

The inhibition of [³⁵S]t-butylbicyclophosphorothionate ([³⁵S]TBPS) binding to the GABA_A receptor by the insecticide γ-hexachlorocyclohexane, lindane, was studied in several brain regions and using different membrane preparation methods, both in vitro and after dosing the animals with the chemical. In the latter studies, the amount of lindane remaining in the membrane suspensions used for binding assays was determined. In vitro data showed values of IC₅₀ from 150 to 1675 nM, varying in function of the membrane preparation method used. This may account for the discrepancies in IC₅₀ values found in the literature. IC₅₀ values within the range of 150–250 nM were determined using extensively washed membranes from several brain regions, so no evidence arose for brain regional differences in the affinity of lindane for the TBPS binding site. After different schedules of acute treatment with lindane, we found a manifest relationship between the extent of the observable inhibition of [³⁵S]TBPS binding and the lindane amount remaining in the membrane suspensions used for binding assays. This relationship was in good agreement with the in vitro data, so no support for an in vivo acute regulation of the binding site was obtained.     

Restriction enzyme fingerprinting of enterobacterial plasmids: a simple strategy with wide application

Restriction enzyme fingerprints were generated from purified plasmid DNA from 324 clinical isolates that belonged to 7 enterobacterial genera and 88 single plasmids in Escherichia coli K 12 according to the following strategy. Purified plasmid DNA was digested with PstI. The number of fragments detected in a 0.8 agarose gel was used to determine which 2 of 6 restriction enzymes including PstI was most likely to provide a fingerprint comprising sufficient fragments to ensure specificity but sufficiently few to allow easy visual assessment and minimize coincidental matching. When PstI produced greater than 20 fragments, EcoRI and HindIII were used; when PstI generated less than 6 fragments Bsp 1286 and AvaII were used and SmaI was employed when between 6 and 20 fragments were obtained from PstI digests. Using a minimum of 12 fragments from a combination of 2 enzymes as the criterion for characterizing a strain/plasmid, satisfactory 2-enzyme fingerprints were obtained from 87% of the strains and plasmids studied using PstI and no more than two additional enzymes per strain. Of the remaining 54 strains, 51 harboured only small plasmids (less than 10 kb) and 3 produced satisfactory fingerprints when digested with a fourth enzyme.     

Higher-order organization and compartmentalization of satellite DNA PIM357 in species of the coleopteran genus Pimelia

The PIM357 satellite DNA family is present in 26 Pimelia taxa (Tenebrionidae, Coleoptera) with endemic congeneric species from the Canary Islands showing higher interrepeat variability than continental ones. In this paper, we compare the repetitive DNA sequences of a Canarian species that has distinct subfamilies of repeat units, P. radula ascendens, with another without such subfamilies, P. sparsa sparsa. The chromosomal localization of the repeat units and the comparison of the variability of randomly cloned monomers to the one estimated by comparing repeat units from dimers and trimers suggest the absence of satellite subfamilies in P. sparsa sparsa. Hence, the repeat units of this species seem to be uniformly and randomly distributed throughout all chromosomes out of one chromosomal pair. On the contrary, P. radula ascendens shows four divergent subfamilies of repeat units supported by several diagnostic nucleotide substitutions. These subfamilies seem to form four distinct repeat units: monomer subfamily 1, monomer subfamily 4 and two higher-order units (dimer linking subfamily 1 and 4, and dimer linking subfamily 2 and 3). Moreover, monomers of subfamily 1 are present in three chromosomal pairs only. We discuss the effect of different potential factors acting in the concerted evolution and the genomic organization of stDNA sequences in these taxa. This revised version was published online in July 2006 with corrections to the Cover Date.