Evaluating the Antimicrobial Properties of Commercial Hand Sanitizers.

Hand sanitizers have been developed as a convenient means to decontaminate an individual's hands of bacterial pathogens in situations in which soap and water are not available. Yet to our knowledge, no study has compared the antibacterial efficacy of a large collection of hand sanitizers. Using zone of growth inhibition and kill curve assays, we assessed the performance of 46 commercially available hand sanitizers that were obtained from national chain big-box stores, gasoline stations, pharmacies, and boutiques for antibacterial activity toward prototypical Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacterial pathogens. Results revealed substantial variability in the efficacy of many sanitizers evaluated. Formulations following World Health Organization-recommended ingredients (80% ethanol or 75% isopropyl alcohol) or those including benzalkonium chloride as the active principal ingredient displayed excellent antibacterial activity, whereas others exhibited modest or poor activity in the assays performed. Results also revealed that E. coli was generally more susceptible to most sanitizers in comparison to S. aureus and that there was significant strain-to-strain variability in hand sanitizer antimicrobial efficacy regardless of the organism evaluated. Further, tests of a subset of hand sanitizers toward severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) revealed no direct correlation between antibacterial and antiviral performance, with all ethyl alcohol formulations performing equally well and displaying improved activity in comparison to benzalkonium chloride-containing sanitizer. Taken together, these results indicate that there is likely to be substantial variability in the antimicrobial performance of commercially available hand sanitizers, particularly toward bacterial pathogens, and a need to evaluate the efficacy of sanitizers under development.IMPORTANCE In response to the coronavirus disease 2019 (COVID-19) pandemic, hand hygiene has taken on a prominent role in efforts to mitigate SARS-CoV-2 transmission and infection, which has led to a radical increase in the number and types of hand sanitizers manufactured to meet public demand. To our knowledge, no studies have evaluated or compared the antimicrobial performance of hand sanitizers that are being produced under COVID-19 emergency authorization. Tests of 46 commercially available hand sanitizers purchased from national chain brick-and-mortar stores revealed considerable variability in their antibacterial performance toward two bacterial pathogens of immediate health care concern, S. aureus and E. coli Expanded testing of a subset of hand sanitizers revealed no direct correlation between antibacterial performance of individual sanitizers and their activity toward SARS-CoV-2. These results indicate that as the pandemic subsides, there will be a need to validate the antimicrobial efficacy of sanitizers being produced.

Karyopherins and kissing cousins.

In eukaryotic cells, a regulated flux of molecules between the cytoplasm and the nucleus maintains two very different environments while allowing the controlled exchange of macromolecules necessary for their individual functions. Molecules entering or leaving the nucleus use nuclear localization signals or nuclear export signals to pass through selective channels in the nuclear envelope formed by nuclear pore complexes. The recognition of signal-bearing cargo, its interaction with the nuclear pore complex and its translocation through the pore complex are mediated by soluble transport factors. Recently, the list of potential transport factors has grown rapidly, suggesting a previously unanticipated level of complexity for nuclear transport.

The single transmembrane segment of gp210 is sufficient for sorting to the pore membrane domain of the nuclear envelope.

The glycoprotein gp210 is located in the "pore membrane," a specialized domain of the nuclear envelope to which the nuclear pore complex (NPC) is anchored. gp210 contains a large cisternal domain, a single transmembrane segment (TM), and a COOH-terminal, 58-amino acid residue cytoplasmic tail (CT) (Wozniak, R. W., E. Bartnik, and G. Blobel. 1989. J. Cell Biol. 108:2083-2092; Greber, U. F., A. Senior, and L. Gerace. 1990. EMBO (Eur. Mol. Biol. Organ.) J. 9:1495-1502). To locate determinants for sorting of gp210 to the pore membrane, we constructed various cDNAs coding for wild-type, mutant, and chimeric gp210, and monitored localization of the expressed protein in 3T3 cells by immunofluorescence microscopy using appropriate antibodies. The large cisternal domain of gp210 (95% of its mass) did not reveal any sorting determinants. Surprisingly, the TM of gp210 is sufficient for sorting to the pore membrane. The CT also contains a sorting determinant, but it is weaker than that of the TM. We propose specific lateral association of the transmembrane helices of two proteins to yield either a gp210 homodimer or a heterodimer of gp210 and another protein. The cytoplasmically oriented tails of these dimers may bind cooperatively to the adjacent NPCs. In addition, we demonstrate that gp210 co-localizes with cytoplasmically dispersed nucleoporins, suggesting a cytoplasmic association of these components.

Primary structure analysis of an integral membrane glycoprotein of the nuclear pore.

The complete primary structure of an integral membrane glycoprotein of the nuclear pore was deduced from the cDNA sequence. The cDNA encodes a polypeptide of 204,205 D containing a 25-residue-long signal sequence, two hydrophobic segments that could function as transmembrane segments, and 13 potential N-linked oligosaccharide addition sites. Endoglycosidase H reduces the molecular mass by approximately 9 kD suggesting that not all of these 13 sites are used. We discuss possible models for the topology of this protein in the pore membrane as well as a possible role in the formation of pores and pore complexes.

POM152 is an integral protein of the pore membrane domain of the yeast nuclear envelope.

We have identified a concanavalin A-reactive glycoprotein of 150 kD that coenriches with isolated yeast nuclear pore complexes. Molecular cloning and sequencing of this protein revealed a single canonical transmembrane segment. Epitope tagging and localization by both immunofluorescence and immunoelectron microscopy confirmed that it is a pore membrane protein. The protein was termed POM152 (for pore membrane protein of 152 kD) on the basis of its location and cDNA-deduced molecular mass. POM152 is likely to be a type II membrane protein with its NH2-terminal region (175 residues) and its COOH-terminal region (1,142 residues) positioned on the pore side and cisternal side of the pore membrane, respectively. The proposed cisternally exposed domain contains eight repetitive motifs of approximately 24 residues. Surprisingly, POM152 deletion mutants were viable and their growth rate was indistinguishable from that of wild-type cells at temperatures between 17 and 37 degrees C. However, overproduction of POM152 inhibited cell growth. When expressed in mouse 3T3 cells, POM152 was found to be localized to the pore membrane, suggesting a conserved sorting pathway between yeast and mammals.

Specific binding of the karyopherin Kap121p to a subunit of the nuclear pore complex containing Nup53p, Nup59p, and Nup170p.

We have identified a specific karyopherin docking complex within the yeast nuclear pore complex (NPC) that contains two novel, structurally related nucleoporins, Nup53p and Nup59p, and the NPC core protein Nup170p. This complex was affinity purified from cells expressing a functional Nup53p-protein A chimera. The localization of Nup53p, Nup59p, and Nup170p within the NPC by immunoelectron microscopy suggests that the Nup53p-containing complex is positioned on both the cytoplasmic and nucleoplasmic faces of the NPC core. In association with the isolated complex, we have also identified the nuclear transport factor Kap121p (Pse1p). Using in vitro binding assays, we showed that each of the nucleoporins interacts with one another. However, the association of Kap121p with the complex is mediated by its interaction with Nup53p. Moreover, Kap121p is the only beta-type karyopherin that binds Nup53p suggesting that Nup53p acts as a specific Kap121p docking site. Kap121p can be released from Nup53p by the GTP bound form of the small GTPase Ran. The physiological relevance of the interaction between Nup53p and Kap121p was further underscored by the observation that NUP53 mutations alter the subcellular distribution of Kap121p and the Kap121p- mediated import of a ribosomal L25 reporter protein. Interestingly, Nup53p is specifically phosphorylated during mitosis. This phenomenon is correlated with a transient decrease in perinuclear-associated Kap121p.

An integral membrane protein of the pore membrane domain of the nuclear envelope contains a nucleoporin-like region.

We have identified an integral membrane protein of 145 kD (estimated by SDS-PAGE) of rat liver nuclear envelopes that binds to WGA. We obtained peptide sequence from purified p145 and cloned and sequenced several cDNA clones and one genomic clone. The relative molecular mass of p145 calculated from its complete, cDNA deduced primary structure is 120.7 kD. Antibodies raised against a synthetic peptide represented in p145 reacted monospecifically with p145. In indirect immunofluorescence these antibodies gave punctate staining of the nuclear envelope. Immunogold EM showed specific decoration of the nuclear pores. Thus p145 is an integral membrane protein located specifically in the "pore membrane" domain of the nuclear envelope. To indicate this specific location, and based on its calculated relative molecular mass, the protein is termed POM 121 (pore membrane protein of 121 kD). The 1,199-residue-long primary structure shows a hydrophobic region (residues 29-72) that is likely to form one (or two adjacent) transmembrane segment(s). The bulk of the protein (residues 73-1199) is predicted to be exposed not on the cisternal side but on the pore side of the pore membrane. It contains 36 consensus sites for various kinases. However, its most striking feature is a repetitive pentapeptide motif XFXFG that has also been shown to occur in several nucleoporins. This nucleoporin-like domain of POM 121 is proposed to function in anchoring components of the nuclear pore complex to the pore membrane.

Nup155 is a novel nuclear pore complex protein that contains neither repetitive sequence motifs nor reacts with WGA.

We have molecularly cloned and sequenced a rat liver nuclear pore complex (NPC) protein of calculated molecular mass of 155 kD. Consistent with recently proposed nomenclature this protein is termed nucleoporin 155, or nup155. Unlike other nups that have so far been molecularly cloned and sequenced, nup155 does not contain repetitive sequence domains. It does not show similarity to the sequences of other proteins, including any nups, so far compiled in the data bases. Like other vertebrate nups which have been characterized nup155 possesses abundant (46 in total) consensus sites for various kinases. By immunoelectron microscopy, nup155 is associated with both the nucleoplasmic and the cytoplasmic aspect of the NPC and is therefore possibly a component of the symmetrically arranged NPC substructures. In mitotic cells, nup155 assumes a diffuse cytoplasmic distribution. Nup155 is among the integral of 30 proteins that were extracted from rat liver nuclear envelopes by 2.0 M urea/1.0 mM EDTA, separated from WGA-reactive proteins by WGA-Sepharose and further subfractionated by SDS-hydroxylapatite. These proteins are potential candidates for being nups.

Yeast nucleoporins involved in passive nuclear envelope permeability.

The vertebrate nuclear pore complex (NPC) harbors an approximately 10-nm diameter diffusion channel that is large enough to admit 50-kD polypeptides. We have analyzed the permeability properties of the Saccharomyces cerevisiae nuclear envelope (NE) using import (NLS) and export (NES) signal-containing green fluorescent protein (GFP) reporters. Compared with wild-type, passive export rates of a classical karyopherin/importin (Kap) Kap60p/Kap95p-targeted NLS-GFP reporter (cNLS-GFP) were significantly faster in nup188-Delta and nup170-Delta cells. Similar results were obtained using two other NLS-GFP reporters, containing either the Kap104p-targeted Nab2p NLS (rgNLS) or the Kap121p-targeted Pho4p NLS (pNLS). Elevated levels of Hsp70 stimulated cNLS-GFP import, but had no effect on the import of rgNLS-GFP. Thus, the role of Hsp70 in NLS-directed import may be NLS- or targeting pathway-specific. Equilibrium sieving limits for the diffusion channel were assessed in vivo using NES-GFP reporters of 36-126 kD and were found to be greater than wild-type in nup188-Delta and nup170-Delta cells. We propose that Nup170p and Nup188p are involved in establishing the functional resting diameter of the NPC's central transport channel.

The yeast nucleoporin Nup188p interacts genetically and physically with the core structures of the nuclear pore complex.

We have isolated a major protein constituent from a highly enriched fraction of yeast nuclear pore complexes (NPCs). The gene encoding this protein, Nup188p, was cloned, sequenced, and found to be nonessential upon deletion. Nup188p cofractionates with yeast NPCs and gives an immunofluorescent staining pattern typical of nucleoporins. Using immunoelectron microscopy, Nup188p was shown to localize to both the cytoplasmic and nucleoplasmic faces of the NPC core. There, Nup188p interacts with an integral protein of the pore membrane domain, Pom152p, and another abundant nucleoporin, Nic96p. The effects of various mutations in the NUP188 gene on the structure of the nuclear envelope and the function of the NPC were examined. While null mutants of NUP188 appear normal, other mutants allelic to NUP188 exhibit a dominant effect leading to the formation of NPC-associated nuclear envelope herniations and growth inhibition at 37 degrees C. In addition, depletion of the interacting protein Pom152p in cells lacking Nup188p resulted in severe deformations of the nuclear envelope. We suggest that Nup188p is one of a group of proteins that form the octagonal core structure of the NPC and thus functions in the structural organization of the NPC and nuclear envelope.

A link between the synthesis of nucleoporins and the biogenesis of the nuclear envelope.

The nuclear pore complex (NPC) is a multicomponent structure containing a subset of proteins that bind nuclear transport factors or karyopherins and mediate their movement across the nuclear envelope. By altering the expression of a single nucleoporin gene, NUP53, we showed that the overproduction of Nup53p altered nuclear transport and had a profound effect on the structure of the nuclear membrane. Strikingly, conventional and immunoelectron microscopy analysis revealed that excess Nup53p entered the nucleus and associated with the nuclear membrane. Here, Nup53p induced the formation of intranuclear, tubular membranes that later formed flattened, double membrane lamellae structurally similar to the nuclear envelope. Like the nuclear envelope, the intranuclear double membrane lamellae enclosed a defined cisterna that was interrupted by pores but, unlike the nuclear envelope pores, they lacked NPCs. Consistent with this observation, we detected only two NPC proteins, the pore membrane proteins Pom152p and Ndc1p, in association with these membrane structures. Thus, these pores likely represent an intermediate in NPC assembly. We also demonstrated that the targeting of excess Nup53p to the NPC and its specific association with intranuclear membranes were dependent on the karyopherin Kap121p and the nucleoporin Nup170p. At the nuclear envelope, the abilities of Nup53p to associate with the membrane and drive membrane proliferation were dependent on a COOH-terminal segment containing a potential amphipathic alpha-helix. The implications of these results with regards to the biogenesis of the nuclear envelope are discussed.

Two novel related yeast nucleoporins Nup170p and Nup157p: complementation with the vertebrate homologue Nup155p and functional interactions with the yeast nuclear pore-membrane protein Pom152p.

We have taken a combined genetic and biochemical approach to identify major constituents of the yeast nuclear pore complex (NPC). A synthetic lethal screen was used to identify proteins which interact genetically with the major pore-membrane protein Pom152p. In parallel, polypeptides present in similar amounts to Pom152p in a highly enriched preparation of yeast NPCs have been characterized by direct microsequencing. These approaches have led to the identification of two novel and major nucleoporins, Nup170p and Nup157p. Both Nup170p and Nup157p are similar to each other and to an abundant mammalian nucleoporin, Nup155p (Radu, A., G. Blobel, and R. W. Wozniak. 1993. J. Cell Biol. 121: 1-9) and interestingly, nup170 mutants can be complemented with mammalian NUP155. In addition, the synthetic lethal screen identified genetic interactions between Pom152p and two other major nucleoporins, Nup188p (Nehrbass, U., S. Maguire, M. Rout, G. Blobel, and R. W. Wozniak, manuscript submitted for publication), and Nic96p (Grandi, P., V. Doye, and E. C. Hurt. 1993. EMBO J. 12: 3061-71). We have determined that together, Nup170p, Nup157p, Pom152p, Nup188p, and Nic96p comprise greater than one-fifth of the mass of the isolated yeast NPC. Examination of the genetic interactions between these proteins indicate that while deletion of either POM152, NUP170, or NUP188 alone is not lethal, pairwise combinations are. Deletion of NUP157 is also not lethal. However, nup157 null mutants, while lethal in combination with nup170 and nup188 null alleles, are not synthetically lethal with pom152 null alleles. We suggest that Nup170p and Nup157p may be part of a morphologically symmetrical but functionally distinct substructure of the yeast NPC, e.g., the nucleoplasmic and cytoplasmic rings. Finally, we observed morphological abnormalities in the nuclear envelope as a function of alterations in the expression levels of NUP170 suggesting a specific stoichiometric relationship between NPC components is required for the maintenance of normal nuclear structure.

Nup2p dynamically associates with the distal regions of the yeast nuclear pore complex.

Nucleocytoplasmic transport is mediated by the interplay between soluble transport factors and nucleoporins resident within the nuclear pore complex (NPC). Understanding this process demands knowledge of components of both the soluble and stationary phases and the interface between them. Here, we provide evidence that Nup2p, previously considered to be a typical yeast nucleoporin that binds import- and export-bound karyopherins, dynamically associates with the NPC in a Ran-facilitated manner. When bound to the NPC, Nup2p associates with regions corresponding to the nuclear basket and cytoplasmic fibrils. On the nucleoplasmic face, where the Ran--GTP levels are predicted to be high, Nup2p binds to Nup60p. Deletion of NUP60 renders Nup2p nucleoplasmic and compromises Nup2p-mediated recycling of Kap60p/Srp1p. Depletion of Ran--GTP by metabolic poisoning, disruption of the Ran cycle, or in vitro by cell lysis, results in a shift of Nup2p from the nucleoplasm to the cytoplasmic face of the NPC. This mobility of Nup2p was also detected using heterokaryons where, unlike nucleoporins, Nup2p was observed to move from one nucleus to the other. Together, our data support a model in which Nup2p movement facilitates the transition between the import and export phases of nucleocytoplasmic transport.

5-Aza-2'-deoxycytidine-mediated reductions in G9A histone methyltransferase and histone H3 K9 di-methylation levels are linked to tumor suppressor gene reactivation.

The epigenetic silencing of tumor suppressor genes is a common event during carcinogenesis, and often involves aberrant DNA methylation and histone modification of gene regulatory regions, resulting in the formation of a transcriptionally repressive chromatin state. Two examples include the antimetastatic, tumor suppressor genes, desmocollin 3 (DSC3) and MASPIN, which are frequently silenced in this manner in human breast cancer. Treatment of the breast tumor cell lines MDA-MB-231 and UACC 1179 with 5-aza-2'-deoxycytidine (5-aza-CdR) induced transcriptional reactivation of both genes in a dose-dependent manner. Importantly, DSC3 and MASPIN reactivation was closely and consistently linked with significant decreases in promoter H3 K9 di-methylation. Moreover, 5-aza-CdR treatment also resulted in global decreases in H3 K9 di-methylation, an effect that was linked to its ability to mediate dose-dependent, post-transcriptional decreases in the key enzyme responsible for this epigenetic modification, G9A. Finally, small interfering RNA (siRNA)-mediated knockdown of G9A and DNMT1 led to increased MASPIN expression in MDA-MB-231 cells, to levels that were supra-additive, verifying the importance of these enzymes in maintaining multiple layers of epigenetic repression in breast tumor cells. These results highlight an additional, complimentary mechanism of action for 5-aza-CdR in the reactivation of epigenetically silenced genes, in a manner that is independent of its effects on DNA methylation, further supporting an important role for H3 K9 methylation in the aberrant repression of tumor suppressor genes in human cancer.

The 210-kD nuclear envelope polypeptide recognized by human autoantibodies in primary biliary cirrhosis is the major glycoprotein of the nuclear pore.

We have recently reported a new family of nuclear autoantibodies in a subset of patients with primary biliary cirrhosis. These antibodies bind to a nuclear envelope polypeptide(s) of approximately 200 kD, the exact identity of which was not established. In this study, we show that all of these autoantibodies are directed against a 210-kD integral membrane glycoprotein of the nuclear pore.

Rrb1p, a yeast nuclear WD-repeat protein involved in the regulation of ribosome biosynthesis.

Ribosome biogenesis is regulated by environmental cues that coordinately modulate the synthesis of ribosomal components and their assembly into functional subunits. We have identified an essential yeast WD-repeat-containing protein, termed Rrb1p, that has a role in both the assembly of the 60S ribosomal subunits and the transcriptional regulation of ribosomal protein (RP) genes. Rrb1p is located in the nucleus and is concentrated in the nucleolus. Its presence is required to maintain normal cellular levels of 60S subunits, 80S ribosomes, and polyribosomes. The function of Rrb1p in ribosome biogenesis appears to be linked to its association with the ribosomal protein rpL3. Immunoprecipitation of Rrb1p from nuclear extracts revealed that it physically interacts with rpL3. Moreover, the overproduction of Rrb1p led to increases in cellular levels of free rpL3 that accumulated in the nucleus together with Rrb1p. The concentration of these proteins within the nucleus was dependent on ongoing protein translation. We also showed that overexpression of RRB1 led to an increase in the expression of RPL3 while all other examined RP genes were unaffected. In contrast, depletion of RRB1 caused an increase in the expression of all RP genes examined except RPL3. These results suggest that Rrb1p regulates RPL3 expression and uncouples it from the coordinated expression of other RP genes.

Intersection of the Kap123p-mediated nuclear import and ribosome export pathways.

Kap123p is a yeast beta-karyopherin that imports ribosomal proteins into the nucleus prior to their assembly into preribosomal particles. Surprisingly, Kap123p is not essential for growth, under normal conditions. To further explore the role of Kap123p in nucleocytoplasmic transport and ribosome biogenesis, we performed a synthetic fitness screen designed to identify genes that interact with KAP123. Through this analysis we have identified three other karyopherins, Pse1p/Kap121p, Sxm1p/Kap108p, and Nmd5p/Kap119p. We propose that, in the absence of Kap123p, these karyopherins are able to supplant Kap123p's role in import. In addition to the karyopherins, we identified Rai1p, a protein previously implicated in rRNA processing. Rai1p is also not essential, but deletion of the RAI1 gene is deleterious to cell growth and causes defects in rRNA processing, which leads to an imbalance of the 60S/40S ratio and the accumulation of halfmers, 40S subunits assembled on polysomes that are unable to form functional ribosomes. Rai1p localizes predominantly to the nucleus, where it physically interacts with Rat1p and pre-60S ribosomal subunits. Analysis of the rai1/kap123 double mutant strain suggests that the observed genetic interaction results from an inability to efficiently export pre-60S subunits from the nucleus, which arises from a combination of compromised Kap123p-mediated nuclear import of the essential 60S ribosomal subunit export factor, Nmd3p, and a DeltaRAI1-induced decrease in the overall biogenesis efficiency.

Interaction of oxygen concentration and retention of pollutants in vertical flow constructed wetlands for CSO treatment.

The EU Water Framework Directive (WFD) calls for a good quality of all water bodies. Retention soil filters (RSF) have been developed to treat discharges from combined sewers systems. RSF have proved over the past 15 years to be the most effective measure to meet the EU WFD standards, especially for small or particularly sensitive receiving waters, which require an enhanced reduction of emissions from combined sewer overflows (CSOs). The paper presents results from laboratory-scale experiments, in which the oxygen measurement in the filter plays a main role. The results show remarkable differences in oxygen concentrations in different filter depths. The highest oxygen consumption takes place in the upper part of the filter. In the lower part the re-aeration of sewage from the soil air dominates. This indicates that the biological activity is limited to the upper part of the filter. The availability of oxygen in the filter is a sign for degradation of wastewater compounds (ammonium, COD) under certain conditions and already takes place during the filter operation. The removal of ammonium especially cannot be strictly divided into phases of sorption during the loading and oxidation during the dry period any more.

Transcutaneous glucose measurement using near-infrared spectroscopy during hypoglycemia.

OBJECTIVE: To analyze a transcutaneous near-infrared spectroscopy system as a technique for in vivo noninvasive blood glucose monitoring during euglycemia and hypoglycemia. RESEARCH DESIGN AND METHODS: Ten nondiabetic subjects and two patients with type 1 diabetes were examined in a total of 27 studies. In each study, the subject's plasma glucose was lowered to a hypoglycemia level (approximately 55 mg/dl) followed by recovery to a glycemic level of approximately 115 mg/dl using an intravenous infusion of insulin and 20% dextrose. Plasma glucose levels were determined at 5-min intervals by standard glucose oxidase method and simultaneously by a near-infrared spectroscopic system. The plasma glucose measured by the standard method was used to create a calibration model that could predict glucose levels from the near-infrared spectral data. The two data sets were correlated during the decline and recovery in plasma glucose, within 10 mg/dl plasma glucose ranges, and were examined using the Clarke Error Grid Analysis. RESULTS: Two sets of 1,704 plasma glucose determinations were examined. The near-infrared predictions during the fall and recovery in plasma glucose were highly correlated (r = 0.96 and 0.95, respectively). When analyzed during 10 mg/dl plasma glucose segments, the mean absolute difference between the near-infrared spectroscopy method and the chemometric reference ranged from 3.3 to 4.4 mg/dl in the nondiabetic subjects and from 2.6 to 3.8 mg/dl in the patients with type 1 diabetes. Using the Error Grid Analysis, 97.7% of all the near-infrared predictions were assigned to the A-zone. CONCLUSIONS: Our findings suggest that the near-infrared spectroscopy method can accurately predict plasma glucose levels during euglycemia and hypoglycemia in humans.

Glucocorticoid suppression of human placental fibronectin expression: implications in uterine-placental adherence.

Increased levels of glucocorticoids are associated with human parturition whether occurring before or at term. In the present study we examined the effects of glucocorticoids on placental fibronectin (FN) expression in cytotrophoblasts, isolated from human term placentas, to provide a potential mechanism through which glucocorticoids may influence uterine-placental adherence near parturition. Based on immunoassays, relative to controls, media levels of placental FNs bearing an oncofetal epitope (onfFN) were inhibited 65-80% by treatment with 10(-7) M dexamethasone (DEX) during experiments in which cumulative levels and daily release of onfFN were measured. DEX treatment increased human CG production by cytotrophoblasts approximately 3-fold without affecting the levels of total protein, suggesting that DEX treatment did not reduce placental function. DEX and cortisol inhibited onfFN expression with an EC50 of 2 and 16 nM, respectively. Other steroids were not effective in down-regulating onfFN expression, indicating that this was a glucocorticoid-specific response. In immunoprecipitation studies, treatment of cytotrophoblasts with 10(-7) M DEX for 3 days inhibited both release of labeled FN to the media and its incorporation into cell-associated material by approximately 80%. Results from Northern blotting indicated that DEX treatment suppressed levels of FN messenger RNA approximately 90% relative to controls. Levels of labeled laminin in media were inhibited approximately 80% by a 3-day treatment with 10(-7) M DEX, suggesting that glucocorticoids may coordinately suppress the synthesis of multiple extracellular matrix proteins in cytotrophoblasts. In our model, we propose that glucocorticoids may suppress placental extracellular matrix protein synthesis, which could lead to decreased uterine-placental adherence and be associated with parturition.