Multispectral imaging of tablets in blister packaging

This experiment tested the hypothesis that using near-infrared (IR) imaging spectrometry on tablets through blister packs permits the identification and composition of multiple individual tablets to be determined simultaneously. Aspirin was selected for this study because its breakdown mechanism is well understood. Near-IR cameras were used to collect thousands of spectra simultaneously from a field of packaged aspirin tablets. Tablets were selected by a principal component analysis selection alogorithm. Graphs of the columns of the transformation matrix showed that salicylic acid and acetylsalicylic acid in the samples were modeled by the principal components. The bootstrap error-adjusted single-sample technique chemometric-imaging algorithm was used to draw probability-density contour plots that revealed tablet composition. Choice of color was used to represent constituent identity, whereas intensity represented concentration. The percentage of usable pixels in the indium antimonide (InSb) array was 99.9%. The SEP was 0.06% of the tablet mass for both water uptake and salicylic acid production. The number of tablets that a typical near-IR camera can currently analyze simultaneously was also estimated to be approximately 1300.     

Modular self-assembly of a Y-shaped multiprotein complex from seven nucleoporins

Now that it is likely that all yeast nucleoporins are known, one of the ultimate goals is the in vitro assembly of the entire nuclear pore complex from its approximately 30 individual components. Here, we report the reconstitution of seven proteins (Nup133p, Nup145p-C, Nup120p, Nup85p, Nup84p, Seh1p and Sec13p) into a heptameric 0.5 MDa nuclear pore subcomplex. We found that double plasmid transformation combined with bi-cistronic mRNA translation allow the expression and assembly of distinct subcomplexes of up to five nucleoporins in a single Escherichia coli cell. During the sequential reconstitution of the Nup84p complex, smaller assembly intermediates can be isolated, which exhibit modular structures determined by electron microscopy that finally make up the whole Y-shaped Nup84p complex. Importantly, a seventh subunit, Nup133p, was incorporated into the complex through its interaction with Nup84p, thereby elongating one arm of the Y-shaped assembly to an approximately 40 nm long stalk. Taken together, our data document that the Nup84p-Nup133p complex self-assembles in a modular concept from distinct smaller nucleoporin construction sets.     

Modulation of rat chorda tympani NaCl responses and intracellular Na+ activity in polarized taste receptor cells by pH

Mixture interactions between sour and salt taste modalities were investigated in rats by direct measurement of intracellular pH (pH(i)) and Na(+) activity ([Na(+)](i)) in polarized fungiform taste receptor cells (TRCs) and by chorda tympani (CT) nerve recordings. Stimulating the lingual surface with NaCl solutions adjusted to pHs ranging between 2.0 and 10.3 increased the magnitude of NaCl CT responses linearly with increasing external pH (pH(o)). At pH 7.0, the epithelial sodium channel (ENaC) blocker, benzamil, decreased NaCl CT responses and inhibited further changes in CT responses induced by varying pH(o) to 2.0 or 10.3. At constant pH(o), buffering NaCl solutions with potassium acetate/acetic acid (KA/AA) or HCO(3)(-)/CO(2) inhibited NaCl CT responses relative to CT responses obtained with NaCl solutions buffered with HEPES. The carbonic anhydrase blockers, MK-507 and MK-417, attenuated the inhibition of NaCl CT responses in HCO(3)(-)/CO(2) buffer, suggesting a regulatory role for pH(i). In polarized TRCs step changes in apical pH(o) from 10.3 to 2.0 induced a linear decrease in pH(i) that remained within the physiological range (slope = 0.035; r(2) = 0.98). At constant pH(o), perfusing the apical membrane with Ringer's solutions buffered with KA/AA or HCO(3)(-)/CO(2) decreased resting TRC pH(i), and MK-507 or MK-417 attenuated the decrease in pH(i) in TRCs perfused with HCO(3)(-)/CO(2) buffer. In parallel experiments, TRC [Na(+)](i) decreased with (a) a decrease in apical pH, (b) exposing the apical membrane to amiloride or benzamil, (c) removal of apical Na(+), and (d) acid loading the cells with NH(4)Cl or sodium acetate at constant pH(o). Diethylpyrocarbonate and Zn(2+), modification reagents for histidine residues in proteins, attenuated the CO(2)-induced inhibition of NaCl CT responses and the pH(i)-induced inhibition of apical Na(+) influx in TRCs. We conclude that TRC pH(i) regulates Na(+)-influx through amiloride-sensitive apical ENaCs and hence modulates NaCl CT responses in acid/salt mixtures.     

Vesicle formation and trafficking in endothelial cells and regulation of endothelial barrier function

Endothelial barrier function is regulated in part by the transcellular transport of albumin and other macromolecules via endothelial caveolae (i.e., this process is defined as transcytosis). Using pulmonary microvascular endothelial cells, we have identified the specific interactions between a cell surface albumin-docking protein gp60 and caveolin-1 as well as components of the signaling machinery, heterotrimeric G protein (G(i))- and Src-family tyrosine kinase. Ligation of gp60 on the apical membrane induces the release of caveolae from the apical membrane and activation of endocytosis. The formed vesicles contain the gp60-bound albumin and also albumin and other solutes present in the fluid phase. Vesicles are transported in a polarized manner to the basolateral membrane, releasing their contents by exocytosis into the subendothelial space. The signaling functions of G(i) and Src are important in the release of caveolae from the plasma membrane. The Src-induced phosphorylation of caveolin-1 is crucial in regulating interactions of caveolin-1 with other components of the signaling machinery such as G(i), and key signaling entry of caveolae into the cytoplasm and endocytosis of albumin and other solutes. This review addresses the basis of transcytosis in endothelial cells, its central role as a determinant of endothelial barrier function, and signaling mechanisms involved in regulating fission of caveolae and trafficking of the formed vesicles from the luminal to abluminal side of the endothelial barrier.     

Arachidonic acid-derived oxidation products initiate apoptosis in vascular smooth muscle cells

The mechanism of arachidonic acid (AA)-induced apoptosis in vascular smooth muscle cells (VSMCs) was studied in the A-10 rat aortic smooth muscle cell line. Treatment of serum-deprived VSMCs with 50 microM AA for 24 h resulted in a loss of cell viability. The apoptotic effect of AA was characterized by annexin V binding, sub-G1 population of cells, cell shrinkage and chromatin condensation. AA-induced VSMC death was attenuated by antioxidants alpha-tocopherol and glutathione, the hydrogen peroxide (H2O2) scavenger catalase and by serum proteins, albumin and gamma globulins. Moreover, the AA peroxidation products, 12(S)-hydroperoxyeicosatetraenoic acid (HPETE), 15(S)-HPETE, 4-hydroxy-2-nonenal (HNE) and malondialdehyde (MDA) caused VSMC apoptosis. These data suggest an oxidative mechanism of AA-induced VSMC death. The apoptotic effect of AA was pH-dependent, being inhibited by extracellular alkalinization to pH 8.0. AA inhibited serum-stimulated cell cycle progression in quiescent cells, but not in proliferating cells. In conclusion, AA, through its oxidation products causes VSMC apoptosis. Antioxidants, by inhibiting VSMC apoptosis, may prevent consequent pathological events such as atherosclerotic plaque rupture.     

A novel locus for Meckel-Gruber syndrome,MKS3, maps to chromosome 8q24

Meckel-Gruber syndrome (MKS), the most common monogenic cause of neural tube defects, is an autosomal recessive disorder characterised by a combination of renal cysts and variably associated features, including developmental anomalies of the central nervous system (typically encephalcoele), hepatic ductal dysplasia and cysts, and polydactyly. Locus heterogeneity has been demonstrated by the mapping of the MKS1locus to 17q21-24 in Finnish kindreds, and of MKS2 to 11q13 in North African-Middle Eastern cohorts. In the present study, we have investigated the genetic basis of MKS in eight consanguineous kindreds, originating from the Indian sub-continent, that do not show linkage to either MKS1 or MKS2. We report the localisation of a third MKS locus ( MKS3) to chromosome 8q24 in this cohort by a genome-wide linkage search using autozygosity mapping. We identified a 26-cM region of autozygosity between D8S586 and D8S1108 with a maximum cumulative two-point LOD score at D8S1179 ( Z(max)=3.04 at theta=0.06). A heterogeneity test provided evidence of one unlinked family. Exclusion of this family from multipoint analysis maximised the cumulative multipoint LOD score at locus D8S1128 ( Z(max)=5.65). Furthermore, a heterozygous SNP in DDEF1, a putative candidate gene, suggested that MKS3 mapped within a 15-cM interval. Comparison of the clinical features of MKS3-linked cases with reports of MKS1- and MKS2-linked kindreds suggests that polydactyly (and possibly encephalocele) appear less common in MKS3-linked families.     

Absence of association between mannose-binding lectin gene polymorphisms and HIV-1 infection in a Colombian population

Mannose-binding lectin (MBL) is a calcium-dependent lectin shown to play an important role in innate immunity to infection by activating the classical complement pathway and phagocytosis. In vitro studies have shown that MBL is able to bind to the gp120 HIV-1 surface antigen, and variants of the gene are associated with increased risk of HIV infection among Scandinavians. We investigated the association of genetic MBL variants and HIV-1 infection in 278 Colombian HIV-infected and control individuals. MBL genotype frequencies were similar for both groups, and no association was detected between MBL alleles B, C, and D and susceptibility to HIV-1 infection ( P=1.0). Since there is a well-documented link between the tested MBL alleles and very low MBL serum concentration, these results do not support the hypothesis that MBL levels are a risk factor for HIV-1 infection in Colombia.