DNA binding by the KP repressor protein inhibits P-element transposase activity in vitro

P elements are a family of mobile DNA elements found in Drosophila. P-element transposition is tightly regulated, and P-element-encoded repressor proteins are responsible for inhibiting transposition in vivo. To investigate the molecular mechanisms by which one of these repressors, the KP protein, inhibits transposition, a variety of mutant KP proteins were prepared and tested for their biochemical activities. The repressor activities of the wild-type and mutant KP proteins were tested in vitro using several different assays for P-element transposase activity. These studies indicate that the site-specific DNA-binding activity of the KP protein is essential for repressing transposase activity. The DNA-binding domain of the KP repressor protein is also shared with the transposase protein and resides in the N-terminal 88 amino acids. Within this region, there is a C2HC putative metal-binding motif that is required for site-specific DNA binding. In vitro the KP protein inhibits transposition by competing with the transposase enzyme for DNA-binding sites near the P-element termini.     

BCG vaccination in low birth weight newborns: analysis of lymphocyte proliferation, IL-2 generation and intradermal reaction to PPD

OBJECTIVE: To study vaccinal scar formation and post-vaccinal immune response in newborns with birth weight ranging from 2000 to 2499 g vaccinated in the first week of life with intradermal bacille Calmette-Guérin (BCG) (Moreau-Rio de Janeiro strain). METHOD: Specific immune response to PPD was assessed in 30 low birth weight newborns (mean birth weight = 2311.7 +/- 122.1 g; mean gestational age = 38.1 +/- 1.8 weeks) in comparison to 56 control infants (mean birth weight = 3198.9 +/- 267.2 g; mean gestational age = 38.5 +/- 1.2 weeks. RESULTS: Low birth weight infants have an efficient immune response to vaccinal stimulus when compared to control infants as judged by specific in vitro lymphocyte proliferation (mean SI = 9.7 +/- 12.9 vs SI = 8.8 +/- 10.0, P = 0.72) and IL-2 production (mean SI = 3.1 +/- 3.4 vs SI = 2.6 +/- 2.0, P = 0.38). Intradermal reaction to PPD was also comparable in both groups (mean induration diameter = 9.5 +/- 5.1 mm vs 9.6 +/- 5.0 mm, P = 0.94). CONCLUSION: These data suggest that low birth weight newborns show a good immune response to BCG, thus reinforcing the inclusion of such infants in regular vaccination programs with intradermal BCG.     

The computational modeling of alloys at the atomic scale: From ab initio and thermodynamics to radiation-induced heterogeneous precipitation

This paper describes a strategy to simulate radiation damage in FeCr alloys wherein magnetism introduces an anomaly in the heat of formation of the solid solution. This has implications for the precipitation of excess chromium in the α′ phase in the presence of heterogeneities. These complexities pose many challenges for atomistic (empirical) methods. To address such issues the authors have developed a modified many-body potential by rigorously fitting thermodynamic properties including free energy. Multi-million atom displacement Monte Carlo simulations in the transmutation ensemble, using the new potential, predict that thermodynamically grain boundaries, dislocations, and free surfaces are not preferential sites for α′ precipitation.     

Progression of renal failure after subtotal nephrectomy in transgenic rats carrying an additional renin gene [TGR(mREN2)27]

Monkey auditory memory was tested with increasing list lengths of 4, 6, 8, and 10 sounds. Five-hundred and twenty environmental sounds of 3-s duration were used. In Experiment 1, the monkeys initiated each list by touching the center speaker. They touched 1 of 2 side speakers to indicate whether a single test sound (presented from both side speakers simultaneously) was or was not in the list. The serial-position functions showed prominent primacy effects (good first-item memory) and recency effects (good last-item memory). Experiment 2 repeated the procedure without the list-initiation response and with a variable intertrial interval. The results of both experiments were similar and are discussed in relation to theories and hypotheses of serial-position effects.     

Effects of age on the posttranscriptional regulation of CCAAT/enhancer binding protein alpha and CCAAT/enhancer binding protein beta isoform synthesis in control and LPS-treated livers

The CCAAT/enhancer binding protein alpha (C/EBPalpha) and CCAAT/enhancer binding protein beta (C/EBPbeta) mRNAs are templates for the differential translation of several isoforms. Immunoblotting detects C/EBPalphas with molecular masses of 42, 38, 30, and 20 kDa and C/EBPbetas of 35, 20, and approximately 8.5 kDa. The DNA-binding activities and pool levels of p42(C/EBPalpha) and p30(C/EBPalpha) in control nuclear extracts decrease significantly whereas the binding activity and protein levels of the 20-kDa isoforms increase dramatically with LPS treatment. Our studies suggest that the LPS response involves alternative translational initiation at specific in-frame AUGs, producing specific C/EBPalpha and C/EBPbeta isoform patterns. We propose that alternative translational initiation occurs by a leaky ribosomal scanning mechanism. We find that nuclear extracts from normal aged mouse livers have decreased p42(C/EBPalpha) levels and binding activity, whereas those of p20(C/EBPalpha) and p20(C/EBPbeta) are increased. However, translation of 42-kDa C/EBPalpha is not down-regulated on polysomes, suggesting that aging may affect its nuclear translocation. Furthermore, recovery of the C/EBPalpha- and C/EBPbeta-binding activities and pool levels from an LPS challenge is delayed significantly in aged mouse livers. Thus, aged livers have altered steady-state levels of C/EBPalpha and C/EBPbeta isoforms. This result suggests that normal aging liver exhibits characteristics of chronic stress and a severe inability to recover from an inflammatory challenge.     

Cadmium toxicity and distribution in metallothionein-I and -II deficient transgenic mice

To date, numerous correlative studies have implicated metallothionein in the detoxification of heavy metals and in the regulation of metal distribution within an organism. In the present study cadmium-binding proteins (metallothionein equivalents), cadmium acute toxicity, and cadmium distribution in tissues and subcellular fractions were compared in metallothionein-I and -II deficient (MT-/-) mice and the parental strain carrying intact metallothionein genes (MT+/+) to determine if the absence of metallothionein altered any of these parameters. In an uninduced state, MT-/- mice expressed lower levels of cadmium-binding proteins relative to MT+/+ mice in several tissues. Administration of zinc enhanced the levels of cadmium-binding proteins in liver, small intestine, kidney, pancreas, and male sex organs, but not in cecum or brain of MT+/+ mice compared to zinc pretreated MT-/- mice. The cadmium LD50 was similar for MT-/-, MT+/+, and zinc-pretreated MT-/- mice (15-17 mumol CdCl2/kg body weight delivered i.p.). However, zinc-pretreated MT+/+ mice had a cadmium LD50 of 58-63 mumol CdCl2/kg body weight. Over two-thirds of cadmium was found in liver, cecum, small intestine, and kidney in both MT+/+ and MT-/- mice; therefore, metallothionein levels do not appear to play a major role in the tissue distribution of cadmium. However, after zinc pretreatment, MT+/+ mice accumulated more cadmium in the liver and less in other tissues, whereas the amount of cadmium in the liver was not altered by zinc pretreatment in MT-/- mice. In general, the cytosolic/particulate ratio of cadmium was significantly higher in tissues of noninduced MT+/+ mice relative to MT-/- mice. This difference was accentuated after zinc pretreatment. Together these results indicate that basal levels of metallothionein do not protect from the acute toxicity of a single i.p. cadmium challenge. Furthermore, it does not appear that the cytosolic compartmentalization of cadmium is correlated with reduced toxicity.     

Acute pulmonary edema caused by ingestion of hydrochlorothiazide

Hydrochlorothiazide is one of most commonly prescribed antihypertensive diuretics. In this case, an allergic reaction to hydrochlorothiazide resulted in severe pulmonary edema. Hydrochlorothiazide, one of the most commonly prescribed drugs, is a diuretic which is usually well tolerated. Common side effects include dizziness, weakness, fatigue, and cramps. These side effects are usually caused by fluid and electrolyte imbalances. Acute pulmonary edema, first reported by Steinberg in 1968, is a rare but potentially life-threatening allergic reaction to hydrochlorothiazide. This case illustrates many of the typical presenting features of the reaction.     

Xenon effects on regional cerebral blood flow assessed by 15O-H2O positron emission tomography: implications for hyperpolarized xenon MRI

Subjective and physiologic effects of 33% inhaled Xe were measured with 15O-water positron emission tomography (PET) in 3 subjects at rest and during visual stimulation. The procedure was well tolerated. Robust functional activations of the visual cortex were obtained after xenon (Xe) inhalation as well as air breathing. However, Xe inhalation was followed by smaller size, but significant decreases of regional cerebral blood flow (rCBF) in visual cortex relative to the air-breathing baseline, both during visual stimulation and at rest. No such decreases were found in other sensory or motor regions.     

Ursodeoxycholic acid improves the hepatic metabolism of essential fatty acids and retinol in children with cystic fibrosis

An ELISA sandwich for the detection of Giardia lamblia antigens in human faeces was standardized. 175 samples were studied: 77 positive, 61 negative to cysts and/or trophozoites by direct faeces test, and 19 positive to other parasite different from G. lamblia. The sensitivity of the technique was 94.8% and the specificity 98.3%. The method detects an antigen concentration of 31 ng. The procedure is simple, sensitive and specific so, it may be useful for diagnosis and in epidemiological studies.