Chronic bronchial allergic inflammation increases alveolar liquid clearance by TNF-alpha -dependent mechanism

Bronchial inflammation in allergic asthma is associated with active exudation from the bronchial tree into the interstitial space of both mucosa and submucosa. The aim of this study was to evaluate epithelial and endothelial permeability as well as alveolar fluid movement in a model of chronic allergic inflammation in Brown-Norway rats sensitized and challenged with ovalbumin (OA). Control groups were challenged with saline solution (C), and rats were immunized by OA but not challenged (Se). Lung sections showed a marked inflammatory infiltrate associated with perivascular and peribronchiolar edema in OA. To measure alveolar liquid clearance, a 5% bovine albumin solution with 1 microCi of (125)I-labeled human albumin was instilled into the air spaces. Alveolar-capillary barrier permeability was evaluated by intravascular injection of 1 microCi of (131)I-labeled albumin. Endothelial permeability was significantly increased in OA, from 0.08 +/- 0.01 in the C group to 0.19 +/- 0.03 in OA group (P < 0.05). Final-to-initial protein ratio was also statistically higher in OA (1.6 +/- 0.05) compared with C (1.38 +/- 0.03, P = 0.01) and Se groups (1.42 +/- 0.03, P = 0.04). Administration of anti-tumor necrosis factor-alpha antibodies within the instillate significantly decreased this ratio (1.32 +/- 0.08, P = 0.003 vs. OA). To conclude, we demonstrated a tumor necrosis factor-alpha-dependent increase in alveolar fluid movement in a model of severe bronchial allergic inflammation associated with endothelial and epithelial leakage.     

Outer pore residues control the H(+) and K(+) sensitivity of the Arabidopsis potassium channel AKT3

The Arabidopsis phloem channel AKT3 is the founder of a subfamily of shaker-like plant potassium channels characterized by weak rectification, Ca(2+) block, proton inhibition, and, as shown in this study, K(+) sensitivity. In contrast to inward-rectifying, acid-activated K(+) channels of the KAT1 family, extracellular acidification decreases AKT3 currents at the macroscopic and single-channel levels. Here, we show that two distinct sites within the outer mouth of the K(+)-conducting pore provide the molecular basis for the pH sensitivity of this phloem channel. After generation of mutant channels and functional expression in Xenopus oocytes, we identified the His residue His-228, which is proximal to the K(+) selectivity filter (GYGD) and the distal Ser residue Ser-271, to be involved in proton susceptibility. Mutations of these sites, H228D and S271E, drastically reduced the H(+) and K(+) sensitivity of AKT3. Although in K(+)-free bath solutions outward K(+) currents were abolished completely in wild-type AKT3, S271E as well as the AKT3-HDSE double mutant still mediated K(+) efflux. We conclude that the pH- and K(+)-dependent properties of the AKT3 channel involve residues in the outer mouth of the pore. Both properties, H(+) and K(+) sensitivity, allow the fine-tuning of the phloem channel and thus seem to represent important elements in the control of membrane potential and sugar loading.     

Male bimaturism and reproductive success in Sumatran orang-utans

Although orang-utans live solitary lives most of the time, theyhave a complex social structure and are characterized by extremesexual dimorphism. However, whereas some adult male orang-utansdevelop full secondary sexual characteristics, such as cheekflanges, others may stay in an "arrested" unflanged conditionfor up to 20 years after reaching sexual maturity. The resultis a marked bimaturism among adult males. Flanged males allowfemales to overlap with their home range and often toleratethe presence of unflanged males. However, wherever possibleflanged males actively prevent unflanged males from copulatingwith females. Two competing hypotheses, previously untested,have been advanced to explain male reproductive behavior andbimaturism in orang-utans: (1) the "range-guardian" hypothesis,which asserts that the flanged males are postreproductive anddefend a range in which they tolerate sexually active, unflangedmale relatives; and (2) the "female choice" hypothesis, whichasserts that flanged males tolerate unflanged males in their range because they rely on female preference to favor flangedmales. We investigated these hypotheses and a third hypothesisthat the two male morphs represent co-existing alternativemale reproductive strategies ("sitting, calling, and waiting"for flanged males versus "going, searching, and finding" forunflanged males). Fecal samples were collected from a well-studiedpopulation in Indonesia, and eight human microsatellites wereanalyzed for 30 individuals that have been behaviorally monitoredfor up to 27 years. By carrying out paternity analysis on 11offspring born over 15 years, we found that unflanged malesfathered about half (6) of the offspring. Relatedness betweensuccessful unflanged males and resident dominant males wassignificantly lower than 0.5, and for some unflanged/flangedmale pairs, relatedness values were negative, indicating thatunflanged males are not offspring of the flanged males.     

Synteny between Arabidopsis thaliana and rice at the genome level: a tool to identify conservation in the ongoing rice genome sequencing project

BLASTX alignment between 189.5 Mb of rice genomic sequence and translated Arabidopsis thaliana annotated coding sequences (CDS) identified 60 syntenic regions involving 4–22 rice orthologs covering ≤3.2 cM (centiMorgan). Most regions are <3 cM in length. A detailed and updated version of a table representing these regions is available on our web site. Thirty-five rice loci match two distinct A.thaliana loci, as expected from the duplicated nature of the A.thaliana genome. One A.thaliana locus matches two distinct rice regions, suggesting that rice chromosomal sequence duplications exist. A high level of rearrangement characterizing the 60 syntenic regions illustrates the ancient nature of the speciation between A.thaliana and rice. The apparent reduced level of microcollinearity implies the dispersion to new genomic locations, via transposon activity, of single or small clusters of genes in the rice genome, which represents a significant additional effector of plant genome evolution.     

Aromatic side-chain interactions in proteins. I. Main structural features

In a data set of 593 nonhomologous proteins from the PDB, we have analyzed the pairing of phenylalanine, tyrosine, tryptophan, and histidine residues with their closest aromatic partner. The frequency distribution of the shortest interatomic distance of partners is bimodal with a sharp peak at approximately 3.8 A and a wider one at a longer distance. Only the 3.8 A peak corresponds to direct ring-ring interactions thus aromatic pairs. The aromatic pairs were separated into two classes, near-sequence pairs and far-sequence pairs. Near sequence pairs stabilize local structure, and far-sequence pairs stabilize tertiary structure. Far-sequence pairs (74% of all pairs) mainly bridge two beta-strands, followed by pairs that bridge a beta-strand and a helix, and pairs that bridge a beta-strand and a random coil structure. Pairs that bridge helices are rare. The secondary structure of the near-sequence pairs depends on the partner distance in the sequence. When the partners are 1, 3, or 4 residues apart in the sequence, pairs are mostly found in helical structures. When the partners are two apart, pairs are mostly found in the same beta-strand. Analysis of the frequency of near sequence pairs supports the hypothesis that aromatic pairing occurs after, rather than before, the formation of secondary structures.     

RCAS1 is associated with ductal breast cancer progression

RCAS1/EBAG9 (receptor-binding cancer antigen expressed on SiSo cells/ estrogen receptor-binding fragment-associated gene 9), an estrogen-transcribed protein, has been shown to be expressed in a wide variety of cancers, including uterine, ovarian, and lung cancer cells. Soluble and membranous RCAS1 proteins may play a role in the immune escape of tumor cells by promoting T lymphocyte inhibition of growth and apoptosis. In the present report, the presence of RCAS1 was revealed in human ductal breast cancer biopsies by immunohistochemistry. Its cytoplasmic expression was exhibited in cancer cells obtained from tumor biopsies and in breast cancer cell lines. RCAS1 significantly correlated with tumor grade. In addition, RCAS1 was identified in MCF7 culture supernatants. Those observations suggest that RCAS1 is a new marker for breast cancer progression and a possible mechanism for breast cancer immune escape.     

Effects of U-46619 on pulmonary hemodynamics before and after administration of BM-573, a novel thromboxane A2 inhibitor

We studied the effects on pulmonary hemodynamics of U-46619, a thromboxane A2 (TXA2) agonist, before and after administration of a novel TXA2 receptor antagonist and synthase inhibitor (BM-573). Six anesthetized pigs (Ago group) received 6 consecutive injections of U-46619 at 30-min interval and were compared with six anesthetized pigs (Anta group) which received an increasing dosage regimen of BM-573 10 min before each U-46619 injection. Consecutive changes in pulmonary hemodynamics, including characteristic resistance, vascular compliance, and peripheral vascular resistance, were continuously assessed during the experimental protocol using a four-element Windkessel model. At 2 mg/kg, BM-573 completely blocked pulmonary hypertensive effects of U-46619 but pulmonary vascular compliance still decreased. This residual effect can probably be explained by a persistent increase in the tonus of the pulmonary vascular wall smooth muscles sufficient to decrease vascular compliance but not vessel lumen diameter. Such molecule could be a promising therapeutic approach in TXA2 mediated pulmonary hypertension as it is the case in pulmonary embolism, hyperacute lung rejection and endotoxinic shock.     

Aesthetic eyelid ptosis correction: a review of technique and cases

Upper eyelid ptosis can present both functional and aesthetic problems. Because proper correction of ptosis can be difficult to achieve, numerous surgical procedures have been developed. Plication of levator aponeurosis can be combined with aesthetic blepharoplasty and facial rejuvenation procedures to successfully address ptosis. The authors assessed the effectiveness of levator aponeurosis plication for correction of acquired upper eyelid ptosis in patients presenting for concomitant cosmetic facial procedures. The medical records of 74 consecutive patients (68 women and six men) who had upper eyelid ptosis correction in conjunction with cosmetic facial procedures from January of 1994 to January of 2000 were reviewed. During this period, 400 endoscopic forehead lifts and 479 face lifts were performed. The correction was performed through an external upper blepharoplasty approach removing an ellipse of skin and orbicularis muscle. Once the orbital septum was opened, a plication of the levator aponeurosis was accomplished by one or more horizontal mattress sutures of 6-0 clear nylon (with the first bite placed at or just medial to the vertical level of the pupil). The average follow-up period was 14 months. Long-term correction of the ptosis was excellent. The complications were minor, with the most common occurrence being asymmetry. Revisions were performed on only four patients. Correction of ptosis can be performed safely and effectively in conjunction with periorbital and facial rejuvenation. The technique described is simple, reliable, and reproducible.     

Ecologic correlates of Toxoplasma gondii exposure in free-ranging neotropical mammals

A serologic survey for Toxoplasma gondii in 18 free-ranging forest mammal species (n = 456) in French Guiana was undertaken with a direct agglutination test. Serum antibody prevalence varied from 0-71%. The relationships between ecologic features of the species and seroprevalence were investigated. Terrestrial mammals were significantly more exposed to T. gondii than other mammals. This result is concordant with oral exposure to T. gondii related to ground dwelling behavior and/or carnivory.     

Mercury methylation independent of the acetyl-coenzyme A pathway in sulfate-reducing bacteria

Sulfate-reducing bacteria (SRB) in anoxic waters and sediments are the major producers of methylmercury in aquatic systems. Although a considerable amount of work has addressed the environmental factors that control methylmercury formation and the conditions that control bioavailability of inorganic mercury to SRB, little work has been undertaken analyzing the biochemical mechanism of methylmercury production. The acetyl-coenzyme A (CoA) pathway has been implicated as being key to mercury methylation in one SRB strain, Desulfovibrio desulfuricans LS, but this result has not been extended to other SRB species. To probe whether the acetyl-CoA pathway is the controlling biochemical process for methylmercury production in SRB, five incomplete-oxidizing SRB strains and two Desulfobacter strains that do not use the acetyl-CoA pathway for major carbon metabolism were assayed for methylmercury formation and acetyl-CoA pathway enzyme activities. Three of the SRB strains were also incubated with chloroform to inhibit the acetyl-CoA pathway. So far, all species that have been found to have acetyl-CoA activity are complete oxidizers that require the acetyl-CoA pathway for basic metabolism, as well as methylate mercury. Chloroform inhibits Hg methylation in these species either by blocking the methylating enzyme or by indirect effects on metabolism and growth. However, we have identified four incomplete-oxidizing strains that clearly do not utilize the acetyl-CoA pathway either for metabolism or mercury methylation (as confirmed by the absence of chloroform inhibition). Hg methylation is thus independent of the acetyl-CoA pathway and may not require vitamin B(12) in some and perhaps many incomplete-oxidizing SRB strains.