Assessment of temporal changes in pulmonary edema with NMR imaging

Nuclear magnetic resonance imaging (NMRI) parameters [longitudinal relaxation time (T1), transverse relaxation time (T2), and signal intensity] acquired at a magnetic field of 2.35 T were validated with a study of nine different phantom gel solutions. This technique was then applied to study 13 anesthetized supine cats, among which 10 had lung edema induced by oleic acid (0.075 ml/kg); the result was compared with postmortem analyses of lung water. Three animals (series A) were imaged until the edema was first visualized in NMRI, usually 15-20 min after oleic acid infusion. Another seven animals (series B) were imaged over 4-5 h. As lung water increased, so did the signal intensity. When edema first appeared, T1, T2, and the volume of the edematous region within the slice in the upper lobes showed no gravity-dependent differences; this was confirmed by postmortem measurements (series A) of lung water. With time, gravity-dependent regions displayed greater volumes of edematous regions and greater T1 values (P less than 0.01), suggesting a continued accumulation of lung water. In comparison, nondependent regions displayed constant volumes of edematous region and lesser T1 values (P less than 0.01), suggesting an increased protein concentration but no change in lung water. This study suggests the potential applicability of NMRI parameters in the assessment of pulmonary edema.     

Cardiovascular adaptations in Andean natives after 6 wk of exposure to sea level

Six male Quechua Indians (34.0 +/- 1.1 yr, 159.5 +/- 2.1 cm, 60.5 +/- 1.6 kg), life-long residents of La Raya, Peru (4,350-m altitude with an average barometric pressure of 460 Torr), were studied using noninvasive methods to determine the structural and functional changes in the cardiovascular system in response to a 6-wk deacclimation period at sea level. Cardiac output, stroke volume, and left ventricular ejection fractions were determined using radionuclide angiographic techniques at rest and during exercise on a cycle ergometer at 40, 60, and 90% of a previously determined maximal O2 consumption. Subjects at rest were subjected to two-dimensional and M-mode echocardiograms and a standard 12-lead electrocardiogram. Hemoglobin and hematocrit were measured on arrival at sea level by use of a Coulter Stacker S+ analyzer. After a 6-wk deacclimation period, all variables were remeasured using the identical methodology. Hemoglobin values decreased significantly over the deacclimation period (15.7 +/- 1.1 to 13.5 +/- 1.2 g/dl; P less than 0.01). The results indicate that the removal of these high-altitude-adapted natives from 4,300 m to sea level for 6 wk results in only minor changes to the cardiac structure and function as measured by these noninvasive techniques.     

Determination of the concentration of complex boronated compounds in biological tissues by inductively coupled plasma atomic emission spectrometry

The application of inductively coupled plasma atomic emission spectrometry (ICP-AES) to the determination of the concentration of complex boron-containing compounds in biological tissue samples is described. Tissue digestion is achieved with perchloric acid and hydrogen peroxide in 1 hr at 75 degrees C. The ICP-AES method gave a linear response for elemental boron concentration in the range 0.05 to 100 ppm and does not require the reduction of the boron to a simple species, such as boric acid. Complete recovery of boron in complex boron cluster compounds was obtained. The procedure has been applied to the determination of the boron content in compounds synthesised for neutron capture therapy and is suitable for use in biodistribution studies of such compounds.     

Induction of DNA double-strand breaks by 157Gd neutron capture

The rationale of boron (10B) neutron capture therapy (BNCT) is based on the high thermal neutron capture cross section of 10B and the limited maximum range (about one cell diameter) of the high LET fission products of the boron neutron capture (NC) reaction. The resulting radiochemical damage is confined to the cell containing the BNC reaction. Although other nuclides have higher thermal neutron capture cross sections than 10B, NC by such nuclides results in the emission of highly penetrating gamma rays. However, gadolinium-157 (157Gd) n-gamma reaction is also accompanied by some internal conversion and, by implication, Auger electron emission. Irradiation of Gd3+-DNA complexes with thermal neutrons results in the induction of DNA double-strand (ds) breaks, but the effect is largely abrogated in the presence of EDTA. Thus, by analogy with the effects of decay of Auger electron-emitting isotopes such as 125I, the Gd NC event must take place in the close proximity of DNA in order to induce a DNA ds break. It is proposed that 157Gd-DNA ligands therefore have potential in NCT. The thermal neutron capture cross section of 157Gd, a nonradioactive isotope, is more than 50 times that of 10B.     

HIV-1 and its envelope glycoprotein down-regulate chemotactic ligand receptors and chemotactic function of peripheral blood monocytes

Peripheral blood monocytes from AIDS patients exhibit defective migratory responses to chemotactic stimuli in vitro and to inflammatory sites in vivo. In studies presented here, normal monocytes were infected with the HIV-1/HTLV-IIIBa-L isolate in vitro and evaluated for chemotactic responsiveness. Within 2 days after viral exposure, but before evidence of virus production in the monocytes, chemotactic activity was significantly impaired. Decreased chemotactic activity was associated with modulation of receptors for the chemotactic ligands, C5a and FMLP, on the monocyte cell surface. In addition to HIV-1, monocytes treated with purified HIV-1 envelope glycoprotein gp120 demonstrated a comparable modulation of chemotactic ligand receptors and migratory function. In addition, the HIV-1 or HIV-1 gp120-treated monocytes were induced to undergo differentiation as monitored by HLA-DR expression. Immunoprecipitation of the gp120 with a specific antibody reversed its effects on monocyte chemotaxis and HLA-DR expression. Taken together, these data indicate that the initial interaction of HIV-1 with the monocyte is not passive, but that the binding of HIV-1 and/or HIV-1 gp120 to the CD4R on monocytes transduces a signal leading to transient monocyte activation.     

Physical mapping of the von Recklinghausen neurofibromatosis region on chromosome 17

The von Recklinghausen neurofibromatosis (NF1) locus has been linked to chromosome 17, and recent linkage analyses place the gene on the proximal long arm. NF1 probably resides in 17q11.2, since two unrelated NF1 patients have been identified who possess constitutional reciprocal translocations involving 17q11.2 with chromosomes 1 and 22. We have used a somatic-cell hybrid from the t(17;22) individual, along with other hybrid cell lines, to order probes around the NF1 locus. An additional probe, 17L1, has been isolated from a NotI linking library made from flow-sorted chromosome 17 material and has been mapped to a region immediately proximal to the translocation breakpoint. While neither NF1 translocation breakpoint has yet been identified by pulse-field gel analysis, an overlap between two probes, EW206 and EW207, has been detected. Furthermore, we have identified the breakpoint in a non-NF1 translocation, SP-3, on the proximal side of the NF1 locus. This breakpoint has been helpful in creating a 1,000-kb pulsed-field map, which includes the closely linked NF1 probes HHH202 and TH17.19. The combined somatic-cell hybrid and pulsed-field gel analysis we report here favors the probe order D17Z1-HHH202-TH17.19-CRYB1-17L1-NF1- (EW206, EW207, EW203, L581, L946)-(ERBB2, ERBA1). The agreement in probe ordering between linkage analysis and physical mapping is excellent, and the availability of translocation breakpoints in NF1 should now greatly assist the cloning of this locus.     

Dehydrodolichyl diphosphate synthase in Sertoli and spermatogenic cells of prepuberal rats

The specific activity of 2,3-dehydrodolichyl diphosphate synthase in homogenates of protease-treated seminiferous tubules, enriched spermatogenic cells, and Sertoli cells changed as a function of the age of prepuberal rats. The highest enzymatic activity occurred in each case in 23-day-old rats. Homogenates of pachytene spermatocytes, spermatids, or Sertoli cells had higher synthase activity than a whole testicular homogenate prepared by protease treatment of tubules. Enzymatic activity in pachytene spermatocytes expressed per mg of protein was about 1.7-fold higher than in spermatids, 5.3-fold higher than in spermatogonia, and about 8.3-fold higher than in spermatozoa. Therefore, the increase in spermatogenic cell synthase before day 23 can be accounted for by the appearance of the pachytene spermatocytes. Enzymatic activity decreased remarkably after the differentiation of spermatids into spermatozoa. Synthase activity in enriched Sertoli cell preparations was 1.5-2.3-fold higher than in spermatogenic cell preparations between days 15 and 30. Therefore, both spermatogenic cells and Sertoli cells contribute to changes in the enzymatic activity in seminiferous tubules during development. These changes may be important in regulating the availability of dolichyl phosphate for glycoprotein synthesis during early stages of differentiation.