Hematopoietic ChemR23 (Chemerin Receptor 23) Fuels Atherosclerosis by Sustaining an M1 Macrophage-Phenotype and Guidance of Plasmacytoid Dendritic Cells to Murine Lesions-Brief Report

Objective- Expression of the chemokine-like receptor ChemR23 (chemerin receptor 23) has been specifically attributed to plasmacytoid dendritic cells (pDCs) and macrophages and ChemR23 has been suggested to mediate an inflammatory immune response in these cells. Because chemokine receptors are important in perpetuating chronic inflammation, we aimed to establish the role of ChemR23-deficiency on macrophages and pDCs in atherosclerosis. Approach and Results- ChemR23-knockout/knockin mice expressing eGFP (enhanced green fluorescent protein) were generated and after crossing with apolipoprotein E-deficient ( Apoe^-/- ChemR23 ^e/e) animals were fed a western-type diet for 4 and 12 weeks. Apoe^-/- ChemR23 ^e/e mice displayed reduced lesion formation and reduced leukocyte adhesion to the vessel wall after 4 weeks, as well as diminished plaque growth, a decreased number of lesional macrophages with an increased proportion of M2 cells and a less inflammatory lesion composition after 12 weeks of western-type diet feeding. Hematopoietic ChemR23-deficiency similarly reduced atherosclerosis. Additional experiments revealed that ChemR23-deficiency induces an alternatively activated macrophage phenotype, an increased cholesterol efflux and a systemic reduction in pDC frequencies. Consequently, expression of the pDC marker SiglecH in atherosclerotic plaques of Apoe^-/- ChemR23 ^e/e mice was declined. ChemR23-knockout pDCs also exhibited a reduced migratory capacity and decreased CCR (CC-type chemokine receptor)7 expression. Finally, adoptive transfer of sorted wild-type and knockout pDCs into Apoe^-/- recipient mice revealed reduced accumulation of ChemR23-deficient pDCs in atherosclerotic lesions. Conclusions- Hematopoietic ChemR23-deficiency increases the proportion of alternatively activated M2 macrophages in atherosclerotic lesions and attenuates pDC homing to lymphatic organs and recruitment to atherosclerotic lesions, which synergistically restricts atherosclerotic plaque formation and progression.

Microbe-host interplay in atopic dermatitis and psoriasis

Despite recent advances in understanding microbial diversity in skin homeostasis, the relevance of microbial dysbiosis in inflammatory disease is poorly understood. Here we perform a comparative analysis of skin microbial communities coupled to global patterns of cutaneous gene expression in patients with atopic dermatitis or psoriasis. The skin microbiota is analysed by 16S amplicon or whole genome sequencing and the skin transcriptome by microarrays, followed by integration of the data layers. We find that atopic dermatitis and psoriasis can be classified by distinct microbes, which differ from healthy volunteers microbiome composition. Atopic dermatitis is dominated by a single microbe (Staphylococcus aureus), and associated with a disease relevant host transcriptomic signature enriched for skin barrier function, tryptophan metabolism and immune activation. In contrast, psoriasis is characterized by co-occurring communities of microbes with weak associations with disease related gene expression. Our work provides a basis for biomarker discovery and targeted therapies in skin dysbiosis.

Atopic dermatitis (AD) and psoriasis (PSO) are associated with dysbiosis. Here, by analyses of skin microbiome and host transcriptome of AD and PSO patients, the authors find distinct microbial and disease-related gene transcriptomic signatures that differentiate both diseases.

The CD48 receptor mediates Staphylococcus aureus human and murine eosinophil activation

BACKGROUND

Allergy is characterized by eosinophilia and an increased susceptibility to microbial infection. Atopic dermatitis (AD) is typically associated with Staphylococcus aureus (SA) colonization. Some of the mechanisms by which SA and its exotoxins interact with eosinophils remain elusive. CD48, a glycosylphosphatidylinositol-anchored receptor belonging to the CD2 family, participates in mast cells-SA stimulating cross-talk, facilitates the formation of the mast cell/eosinophils effector unit and as expressed by eosinophils, mediates experimental asthma.

OBJECTIVE

To investigate the role of CD48 expressed on human peripheral blood and mouse bone marrow-derived eosinophils (BMEos) in their interaction with heat-killed SA and its three exotoxins, Staphylococcal enterotoxin B (SEB), protein A (PtA) and peptidoglycan (PGN).

METHODS

Eosinophils were obtained from human peripheral blood and BM of WT and CD48-/- mice. SA was heat killed and eosinophils-SA/exotoxins interactions were analyzed by confocal microscopy, adhesion and degranulation, cell viability, cytokine release and cell signalling. In addition, peritonitis was induced by SEB injection into CD48-/- and WT mice. CD48 expression was studied in AD patients' skin and as expressed on their leucocytes in the peripheral blood.

RESULTS

We provide evidence for the recognition and direct physical interaction between eosinophils and SA/exotoxins. Skin of AD patients showed a striking increase of eosinophil-associated CD48 expression while on peripheral blood leucocytes it was down-regulated. SA/exotoxins enhanced CD48 eosinophil expression, bound to CD48 and caused eosinophil activation and signal transduction. These effects were significantly decreased by blocking CD48 on human eosinophils or in BMEos from CD48-/- mice. We have also explored the role of CD48 in a SEB-induced peritonitis model in CD48-/- mice by evaluating inflammatory peritoneal cells, eosinophil numbers and activation.

CONCLUSIONS

These data demonstrate the important role of CD48 in SA/exotoxins-eosinophil activating interactions that can take place during allergic responses and indicate CD48 as a novel therapeutic target for allergy and especially of AD.

A sensory neuron-expressed IL-31 receptor mediates T helper cell-dependent itch: Involvement of TRPV1 and TRPA1

BACKGROUND

Although the cytokine IL-31 has been implicated in inflammatory and lymphoma-associated itch, the cellular basis for its pruritic action is yet unclear.

OBJECTIVE

We sought to determine whether immune cell-derived IL-31 directly stimulates sensory neurons and to identify the molecular basis of IL-31-induced itch.

METHODS

We used immunohistochemistry and quantitative real-time PCR to determine IL-31 expression levels in mice and human subjects. Immunohistochemistry, immunofluorescence, quantitative real-time PCR, in vivo pharmacology, Western blotting, single-cell calcium imaging, and electrophysiology were used to examine the distribution, functionality, and cellular basis of the neuronal IL-31 receptor α in mice and human subjects.

RESULTS

Among all immune and resident skin cells examined, IL-31 was predominantly produced by TH2 and, to a significantly lesser extent, mature dendritic cells. Cutaneous and intrathecal injections of IL-31 evoked intense itch, and its concentrations increased significantly in murine atopy-like dermatitis skin. Both human and mouse dorsal root ganglia neurons express IL-31RA, largely in neurons that coexpress transient receptor potential cation channel vanilloid subtype 1 (TRPV1). IL-31-induced itch was significantly reduced in TRPV1-deficient and transient receptor channel potential cation channel ankyrin subtype 1 (TRPA1)-deficient mice but not in c-kit or proteinase-activated receptor 2 mice. In cultured primary sensory neurons IL-31 triggered Ca(2+) release and extracellular signal-regulated kinase 1/2 phosphorylation, inhibition of which blocked IL-31 signaling in vitro and reduced IL-31-induced scratching in vivo.

CONCLUSION

IL-31RA is a functional receptor expressed by a small subpopulation of IL-31RA(+)/TRPV1(+)/TRPA1(+) neurons and is a critical neuroimmune link between TH2 cells and sensory nerves for the generation of T cell-mediated itch. Thus targeting neuronal IL-31RA might be effective in the management of TH2-mediated itch, including atopic dermatitis and cutaneous T-cell lymphoma.

Two-dimensional Fermi liquid with attractive interactions

We realize and study an attractively interacting two-dimensional Fermi liquid. Using momentum-resolved photoemission spectroscopy, we measure the self-energy, determine the contact parameter of the short-range interaction potential, and find their dependence on the interaction strength. We successfully compare the measurements to a theoretical analysis, properly taking into account the finite temperature, harmonic trap, and the averaging over several two-dimensional gases with different peak densities.

New tools for assessing the individual risk of metastasis in renal cell carcinoma

Localized renal cell carcinoma (RCC) progresses to metastatic disease in 20-40 % after surgical resection. Affected patients might benefit from adjuvant treatment and have to be reliably identified for treatment indication. However, existing molecular markers and classification nomograms lack sufficient validity for clinical application so far. Therefore, in order to improve diagnostic tools for the identification of patients at risk, we tested invasiveness and the capability to activate vascular endothelium of primary RCC cells as tumor specific functional parameters. As a parameter for cell invasiveness the ability of RCC cells to break-down transepithelial electrical resistance (TEER) of an epithelial cell monolayer was tested. Loss of resistance, calculated as invasivity index, resembled the degree of cell invasiveness. In addition, secretion of Von Willebrand Factor by endothelial cells incubated with RCC cell supernatant was measured as a surrogate marker for endothelial cell activation. TEER-assay results matched clinical status of disease in 9 out of 12 cases. Metastatic tumors and less differentiated tumors had a significant increase of invasivity index (p = 0.007; p = 0.034). Endothelial cell activation and clinical outcome matched in 5 out of 9 samples. In addition, tumor cell induced endothelial cell activation significantly correlated to the pathologic T classification status of RCC tumors (p = 0.009). Taken together, our study validated endothelial cell activation analysis and cell invasiveness as solitary prognostic markers for tumor dissemination. TEER-analysis has proven to be a useful functional assay giving highly relevant individual information on functional tumor cell characteristics that add to pathologic evaluation.

α-1-Antitrypsin and IFN-γ reduce the severity of IC-mediated vasculitis by regulation of leukocyte recruitment in vivo

IC-mediated vasculitis (ICV) can be life threatening. The cellular and immune mechanisms controlling ICV are poorly understood. Therefore, we investigated the role of α-1-antitrypsin (α1AT) and IFN-γ in reducing the severity of ICV in a mouse model in vivo. To induce ICV, mice were challenged with the reverse passive Arthus reaction (RPA), the prototypic in vivo model for leukocytoclastic vasculitis (LcV), and the modulation of vascular permeability, edema formation, and leukocyte recruitment was studied. To further analyze the dynamics of RPA, we applied intravital microscopy in the dorsal skinfold chamber. α1AT continuously led to reduced leukocyte recruitment. α1AT interfered with neutrophil recruitment through a KC-dependent mechanism and reduced KC-elicited neutrophil activation. In contrast to α1AT, IFN-γ-reduced leukocyte recruitment during RPA was clearly independent of KC. We also revealed that the recruitment of neutrophils during RPA was a prerequisite for full KC expression. Thus, therapeutic administration of α1AT and IFN-γ might be beneficial for limiting the duration and severity of ICV.

Protein phosphatase 2A mediates resensitization of the neurokinin 1 receptor

Activated G protein-coupled receptors (GPCRs) are phosphorylated and interact with β-arrestins, which mediate desensitization and endocytosis. Endothelin-converting enzyme-1 (ECE-1) degrades neuropeptides in endosomes and can promote recycling. Although endocytosis, dephosphorylation, and recycling are accepted mechanisms of receptor resensitization, a large proportion of desensitized receptors can remain at the cell surface. We investigated whether reactivation of noninternalized, desensitized (phosphorylated) receptors mediates resensitization of the substance P (SP) neurokinin 1 receptor (NK(1)R). Herein, we report a novel mechanism of resensitization by which protein phosphatase 2A (PP2A) is recruited to dephosphorylate noninternalized NK(1)R. A desensitizing concentration of SP reduced cell-surface SP binding sites by only 25%, and SP-induced Ca(2+) signals were fully resensitized before cell-surface binding sites started to recover, suggesting resensitization of cell-surface-retained NK(1)R. SP induced association of β-arrestin1 and PP2A with noninternalized NK(1)R. β-Arrestin1 small interfering RNA knockdown prevented SP-induced association of cell-surface NK(1)R with PP2A, indicating that β-arrestin1 mediates this interaction. ECE-1 inhibition, by trapping β-arrestin1 in endosomes, also impeded SP-induced association of cell-surface NK(1)R with PP2A. Resensitization of NK(1)R signaling required both PP2A and ECE-1 activity. Thus, after stimulation with SP, PP2A interacts with noninternalized NK(1)R and mediates resensitization. PP2A interaction with NK(1)R requires β-arrestin1. ECE-1 promotes this process by releasing β-arrestin1 from NK(1)R in endosomes. These findings represent a novel mechanism of PP2A- and ECE-1-dependent resensitization of GPCRs.

Role of proteinase-activated receptor-2 in anti-bacterial and immunomodulatory effects of interferon-γ on human neutrophils and monocytes

Recent studies show that proteinase-activated receptor-2 (PAR(2)) contributes to the development of inflammatory responses. However, investigations into the precise role of PAR(2) activation in the anti-microbial defence of human leucocytes are just beginning. We therefore evaluated the contribution of PAR(2) to the anti-microbial response of isolated human innate immune cells. We found that PAR(2) agonist, acting alone, enhances phagocytosis of Staphylococcus aureus and killing of Escherichia coli by human leucocytes, and that the magnitude of the effect is similar to that of interferon-γ (IFN-γ). However, co-application of PAR(2) -cAP and IFN-γ did not enhance the phagocytic and bacteria-killing activity of leucocytes beyond that triggered by either agonist alone. On the other hand, IFN-γ enhances PAR(2) agonist-induced monocyte chemoattractant protein 1 (MCP-1) secretion by human neutrophils and monocytes. Furthermore, phosphoinositide-3 kinase and janus kinase molecules are involved in the synergistic effect of PAR(2) agonist and IFN-γ on MCP-1 secretion. Our findings suggest a potentially protective role of PAR(2) agonists in the anti-microbial defence established by human monocytes and neutrophils.

Counting atoms using interaction blockade in an optical superlattice

We report on the observation of an interaction blockade effect for ultracold atoms in optical lattices, analogous to the Coulomb blockade observed in mesoscopic solid state systems. When the lattice sites are converted into biased double wells, we detect a discrete set of steps in the well population for increasing bias potentials. These correspond to tunneling resonances where the atom number on each side of the barrier changes one by one. This allows us to count and control the number of atoms within a given well. By evaluating the amplitude of the different plateaus, we can fully determine the number distribution of the atoms in the lattice, which we demonstrate for the case of a superfluid and Mott insulating regime of 87Rb.

Intracellular degradation of somatostatin-14 following somatostatin-receptor3-mediated endocytosis in rat insulinoma cells

Somatostatin receptor (SSTR) endocytosis influences cellular responsiveness to agonist stimulation and somatostatin receptor scintigraphy, a common diagnostic imaging technique. Recently, we have shown that SSTR1 is differentially regulated in the endocytic and recycling pathway of pancreatic cells after agonist stimulation. Additionally, SSTR1 accumulates and releases internalized somatostatin-14 (SST-14) as an intact and biologically active ligand. We also demonstrated that SSTR2A was sequestered into early endosomes, whereas internalized SST-14 was degraded by endosomal peptidases and not routed into lysosomal degradation. Here, we examined the fate of peptide agonists in rat insulinoma cells expressing SSTR3 by biochemical methods and confocal laser scanning microscopy. We found that [(125)I]Tyr11-SST-14 rapidly accumulated in intracellular vesicles, where it was degraded in an ammonium chloride-sensitive manner. In contrast, [(125)I]Tyr1-octreotide accumulated and was released as an intact peptide. Rhodamine-B-labeled SST-14, however, was rapidly internalized into endosome-like vesicles, and fluorescence signals colocalized with the lysosomal marker protein cathepsinD. Our data show that SST-14 was cointernalized with SSTR3, was uncoupled from the receptor, and was sorted into an endocytic degradation pathway, whereas octreotide was recycled as an intact peptide. Chronic stimulation of SSTR3 also induced time-dependent downregulation of the receptor. Thus, the intracellular processing of internalized SST-14 and the regulation of SSTR3 markedly differ from the events mediated by the other SSTR subtypes.

Agonists of proteinase-activated receptor-2 enhance IFN-gamma-inducible effects on human monocytes: role in influenza A infection

Proteinase-activated receptor-2 (PAR(2)) is expressed by different types of human leukocytes and involved in the development of inflammatory and infectious diseases. However, its precise role in the regulation of human monocyte and macrophage function during viral infection remains unclear. Also, the ability of PAR(2) agonists to enhance the effects induced by immune mediators during infection or inflammation is still poorly investigated. Therefore, we investigated the ability of a PAR(2) agonist to enhance IFN-gamma-induced suppression of influenza A virus replication in human monocytes. We found that this effect correlates with an increased abundance of IkappaBalpha after costimulation of cells with PAR(2) agonist and IFN-gamma. Remarkably, coapplication of PAR(2) agonist and IFN-gamma also enhances the effects of IFN-gamma on IFN-gamma-inducible protein 10 kDa release, and CD64 and alphaVbeta3 surface expression by human monocytes. Together, these findings indicate a potentially protective role of PAR(2) activation during the progression of influenza A virus infection. This effect could be associated with the ability of PAR(2) agonists to enhance IFN-gamma-induced protective effects on human monocytes.

Agonists of proteinase-activated receptor-2 affect transendothelial migration and apoptosis of human neutrophils

Skin is the first barrier preventing microorganism invasion in host. Wounds destroy this defense barrier and, without an appropriate care, may lead to sepsis. Neutrophil activation and immigration plays an important role at the inflammatory stage of wound healing. Neutrophils are known to express proteinase-activated receptors (PARs), which can be activated by serine proteases, also by enzymes involved in wound healing. We previously reported that PAR(2) agonists up-regulate cell adhesion molecule expression and cytokine production by human neutrophils. Here, we demonstrate that PAR(2) agonists (serine proteases as well as synthetic peptides) reduce transendothelial migration of neutrophils and prolong their life in vitro. Synthetic PAR(2) agonist also enhanced protective interferon (IFN)gamma-induced FcgammaRI expression at neutrophil cell surface. Of note, IFNgamma is a cytokine, which was used in clinical trials to reactivate human neutrophil functions during sepsis. Moreover, we observed a significant increase of PAR(2) expression on cell surface of neutrophils from septic patients as compared with healthy volunteers. Together, our results indicate that PAR(2) may be involved in the pathophysiology of neutrophil-endothelial interactions during wound healing or later during sepsis in humans, potentially by affecting neutrophil apoptosis, transendothelial migration and Fcgamma receptor-mediated phagocytosis.

Protease-activated receptors: novel PARtners in innate immunity

Protease-activated receptors (PARs) belong to a family of G protein-coupled receptors activated by serine proteases via proteolytic cleavage. PARs are expressed on epithelial cells, endothelial cells, and leukocytes, indicating a role in controlling barrier function against external danger. During inflammation, microorganisms as well as host immune cells release various proteases activating PARs. Thus, PARs can be viewed as an integral component of the host antimicrobial alarm system. When stimulated, PARs regulate various functions of leukocytes in vivo and in vitro, revealing a novel pathway by which proteases affect innate immune responses. Understanding protease-immune interactions could lead to novel strategies for the treatment of infectious and immune-related diseases.

Direct observation of second-order atom tunnelling

Tunnelling of material particles through a classically impenetrable barrier constitutes one of the hallmark effects of quantum physics. When interactions between the particles compete with their mobility through a tunnel junction, intriguing dynamical behaviour can arise because the particles do not tunnel independently. In single-electron or Bloch transistors, for example, the tunnelling of an electron or Cooper pair can be enabled or suppressed by the presence of a second charge carrier due to Coulomb blockade. Here we report direct, time-resolved observations of the correlated tunnelling of two interacting ultracold atoms through a barrier in a double-well potential. For the regime in which the interactions between the atoms are weak and tunnel coupling dominates, individual atoms can tunnel independently, similar to the case of a normal Josephson junction. However, when strong repulsive interactions are present, two atoms located on one side of the barrier cannot separate, but are observed to tunnel together as a pair in a second-order co-tunnelling process. By recording both the atom position and phase coherence over time, we fully characterize the tunnelling process for a single atom as well as the correlated dynamics of a pair of atoms for weak and strong interactions. In addition, we identify a conditional tunnelling regime in which a single atom can only tunnel in the presence of a second particle, acting as a single atom switch. Such second-order tunnelling events, which are the dominating dynamical effect in the strongly interacting regime, have not been previously observed with ultracold atoms. Similar second-order processes form the basis of superexchange interactions between atoms on neighbouring lattice sites of a periodic potential, a central component of proposals for realizing quantum magnetism.

Intensities of calcium dipicolinate and Bacillus subtilis spore Raman spectra excited with 244 nm light

Ultraviolet (UV) resonance Raman spectra of Bacillus subtilis endospores have been excited at 244 nm. Spectra can be interpreted in terms of contributions from calcium dipicolinate and nucleic acid components. Differences between spectra of spores and vegetative cells are very large and are due to the dominance of the dipicolinate features in the spore spectra. Because the DNA and RNA composition of B. subtilis spores is known and because the cross-sections of Raman bands belonging to DNA and RNA bases are known, it is possible to calculate resonance Raman spectral cross-sections for the spore Raman peaks associated with the nucleic acids. The cross-sections of peaks associated with calcium dipicolinate have been measured from aqueous solutions. Cross-section values of the dominant 1017 cm(-1) calcium dipicolinate peak measured from the Bacillus spores have been shown to be consistent with a calcium dipicolinate composition of ten percent or less by weight in the spores. It is suggested that spectral cross-sections of endospores excited at 244 nm can be estimated to be the sum of the cross-sections of the calcium dipicolinate, DNA, and RNA components of the spore. It appears that the peaks due to DNA and RNA can be used as an internal standard in the calculation of spore Raman peak cross-sections, and potentially the amount of calcium dipicolinate in spores. It is estimated on the basis of known nucleic acid base cross-sections that the most intense Raman band of the Bacillus subtilis spore spectra has a cross-section of no more than 4 x 10(-18) cm(2)/mol-sr.

Hepatitis B virus S gene mutants in a patient with chronic active hepatitis with circulating Anti-HBs antibodies

An adult male farmer with chronic active hepatitis and cirrhosis despite previous circulating anti-HBs antibodies was studied. No markers of other hepatotropic viral infection were observed. HBV DNA was detected in serum by PCR and was characterized further by restriction fragment length polymorphism (RFLP) and sequencing of cloned PCR products derived from the S gene. The HBV DNA was ascribed to genotype F, and single-strand conformational polymorphism (SSCP) demonstrated the co-circulation of multiple quasispecies. Some of the variants exhibited changes located within the neutralizing "a" determinant, located between amino acids 124-147 of the S protein. Within this region, two clones showed either C124R or C124Y mutations. Other mutations were Q129R, C138R, C139R, and S140T (one clone each). Outside the "a" determinant several substitutions were documented. The high degree of the quasispecies variability was probably linked to the severity of the infection. Most members of the patient's family were infected with HBV, all with genotype F.

Preoperative cardiac assessment of the candidate for major resective pancreatic surgery

The risk of perioperative cardiac morbidity and mortality can be predicted based on clinical assessment and noninvasive testing for the detection of myocardial ischemia. Appropriate preoperative interventions in high-risk patients are indicated. Medical intervention with beta blockade is particularly effective.

Genomic and phylogenetic analysis of hepatitis C virus isolates from argentine patients: a six-year retrospective study

Typing of hepatitis C virus (HCV) isolates from Argentine patients was performed by using different methodologies in a population of 243 patients. HCV subtype was assigned based upon restriction fragment length polymorphism (RFLP). HCV RNA genomes obtained from serum samples were classified as belonging to clade 1 (53.5%), 2 (23. 0%), or 3 (8.6%); 14.8% of samples showed HCV mixed infections, more frequently implying different subtypes within the same clade. In addition to RFLP typing, phylogenetic relatedness among sequences from both 5' untranslated region (n = 50) and nonstructural 5B coding region (n = 15) was established.

Intensities of E. coli nucleic acid Raman spectra excited selectively from whole cells with 251-nm light

Escherichia coli bacteria in the logarithmic growth phase have been investigated by UV resonance Raman spectroscopy. Bacterial whole-cell Raman spectra excited at 251 nm reflect nearly exclusively the nucleic acid composition even though a very large fraction of the bacterial mass is composed of protein. It has been demonstrated that if bacteria are grown under controlled (logarithmic growth) conditions, which give rise to organisms of known average biochemical composition, the intensities of E. coli Raman spectra can be explained quantitatively from the knowledge of component nucleic acid base resonance Raman cross sections.

UV resonance Raman detection and quantitation of domoic acid in phytoplankton

Cultures of the phytoplankton diatom, Pseudonitzschia multiseries, have been harvested under controlled growth conditions ranging from late logarithmic to late stationary phase (17-58 days). The amount of domoic acid (DA) present in the growth media and in the homogenized cells has been determined by HPLC. Defined samples of media, homogenized cells, whole cells, and whole cells in media have been laser excited at 251 nm for the purpose of selectively exciting intense UV resonance Raman spectra from DA in the samples. Neither media nor cell component spectra from algae seriously interfere with DA spectra. The spectral cross sections for the dominant 1652-cm-1 mode of DA have been determined for 242-, 251-, and 257-nm excitation. Maximum sensitivities are achieved with 251-nm excitation because cross sections for DA are a maximum, and interference from other algal components becomes very small. DA concentrations that have been determined with 251-nm excitation by resonance Raman methods correlate closely with values determined independently with HPLC, especially at higher DA concentrations. The UV resonance Raman analysis of DA in phytoplankton algae is shown to be very sensitive and quantitative as well as rapid and nonintrusive.

Genetic diversity of GBV-C/HGV strains among HIV infected-IVDU and blood donors from Buenos Aires, Argentina

GBV-C/HGV RNA was investigated in serum samples from 70 HIV(+) intravenous drug users (IVDU), as well as from 200 blood donors from Buenos Aires, Argentina. Viral RNA was demonstrated in 21 IVDU by reverse transcription-nested PCR of the 5' UTR. c-DNA amplified products were analyzed and their sequences compared with those downloaded from GenBank. A phylogenetic tree based on 171 sequences demonstrated the presence of three major genogroups, including two subgroups, within local samples, i.e. group 1 (n=1), 2a (n=11), 2b (n=4) and 3 (n=5). These results agreed entirely with those obtained by a novel RFLP (J. Clin. Microbiol. 37, 1340-1347, 1999) of the same 5' UTR amplicons. As expected, GBV-C/HGV RNA prevalence was significantly higher among IVDU than among blood donors (P<0.0001), although within the latter group an unexpectedly high rate was also detected, since 11 of 200 sera (5.5%) proved positive. These viral isolates were ascribed either to subgroup 2a (n=5), subgroup 2b (n=5) or genogroup 3 (n=1). Briefly, this partial view of GBV-C/HGV molecular epidemiology in Argentina shows: (i) different rates of GBV-C/HGV infection within both IVDU and blood donors; (ii) a high prevalence of viral RNA among blood donors; and (iii) a predominant circulation of genogroup 2, with minor contribution of groups 3 and 1.

GB virus C/hepatitis G virus groups and subgroups: classification by a restriction fragment length polymorphism method based on phylogenetic analysis of the 5' untranslated region

A phylogenetic tree based on 150 5' untranslated region sequences deposited in GenBank database allowed segregation of the sequences into three major groups, including two subgroups, i.e., 1, 2a, 2b, and 3, supported by bootstrap analysis. Restriction site analysis of these sequences predicted that HinfI and either AatII or AciI could be used for genomic typing with 99.4% accuracy. cDNA sequencing and subsequent alignment of 21 Argentine GB virus C/hepatitis G virus strains confirmed restriction fragment length polymorphism patterns theoretically predicted. This method may be useful for a rapid screening of samples when either epidemiological or transmission studies of this agent are carried out.

Safety, efficacy, and cost of pancreaticoduodenal resection in a specialized center based at a community hospital

OBJECTIVE

To determine whether pancreaticoduodenal resection (PDR) for benign and malignant disease can be performed safely, efficiently, and economically at a 50-bed community hospital.

DESIGN

Retrospective review of 39 consecutive PDRs performed in an 18-month period. Indications for surgery, length of hospital stay, complications, and patient charges were analyzed.

SETTING

A suburban 50-bed community hospital.

PATIENTS

Thirty-nine patients (15 male and 24 female) referred for PDR for benign and malignant disease.

MAIN OUTCOME MEASURES

Mortality and morbidity rates, length of hospital stay, care, and cost.

RESULTS

Of 39 patients who underwent PDRs, 1 patient (2.6%) died of myocardial infarct. Intraoperative blood transfusions were required by 3 patients (8%). The mean postoperative hospital stay was 11 days. Twenty-four patients (62%) were discharged by day 11. Fifteen patients (38%) were hospitalized 11 to 24 days. Complications in 10 patients (28%) included pancreatic or biliary fistula (n = 6), upper gastrointestinal tract bleeding (n = 1), partial wound dehiscence (n = 1), bacteremia (n = 1), and pneumonia (n = 1). No patient required reoperation. Three patients were rehospitalized within 1 month. Mean patient charges were $21,864, and mean reimbursements were $19,669.

CONCLUSIONS

Pancreaticoduodenal resection can be accomplished with low morbidity and mortality rates and a short stay at a community hospital. Thorough preoperative investigations to exclude unresectable lesions must precede every PDR for malignant disease. Mortality and morbidity rates in this series were similar to those for patients with similar diagnoses who were operated on in academic centers. Cost for and length of hospital stay of these 39 patients were significantly lower than those in other reported series.

Ectopic supernumerary kidney: another cause of a pelvic mass

Ectopic supernumerary pelvic kidney is a rare cause of a pelvic mass in the adolescent populations. We present a case of an ectopic supernumerary pelvic kidney, found incidentally, on a computed axial tomographic (CT) examination.

Spontaneous coronary dissection treated with directional coronary atherectomy

We report a case of spontaneous coronary dissection occurring in a middle aged male which was treated with thrombolytic therapy and directional coronary atherectomy. This technique provides a new option for treating this entity in the cardiac catheterization laboratory.

Characterization of ultraviolet laser-induced autofluorescence of ceroid deposits and other structures in atherosclerotic plaques as a potential diagnostic for laser angiosurgery

Unstained frozen sections of normal and atherosclerotic human aorta and coronary artery were examined using histochemical and fluorescence microscopic techniques to identify the structures responsible for autofluorescence under 351 to 364 nm laser excitation. These structures included elastin and collagen in normal and atherosclerotic specimens, calcium deposits in calcified plaques, and granular or ring-shaped deposits histochemically identified as ceroid found in both calcified and non-calcified plaques. Qualitatively, both the color and intensity of ceroid autofluorescence differed greatly from that of elastin or collagen. The emission spectra of elastin, collagen, and ceroid were examined by microscopic spectrofluorimetry, and were found to differ significantly as well. When compared with spectra of elastin and collagen, spectra of ceroid were broader, shifted to the red, and were somewhat resistant to bleaching. We conclude that detection of laser-induced ceroid autofluorescence may aid in identifying plaques for laser ablation.

Traumatic rupture of the thoracic aorta

Because the diagnosis of a traumatic rupture of the aorta can be subtle, a high index of clinical suspicion must be maintained to arrive at a prompt and correct diagnosis. When chest radiography shows that the mediastinum is greater than 8 cm in width or that the arch or descending aorta are obscured, direct transfemoral arteriography remains the procedure of choice in hemodynamically stabilized patients. At the present time, computed tomography is not recommended as a definitive diagnostic modality.

Lyme carditis: an important cause of reversible heart block

Lyme disease is a tick-borne spirochetal infection, characterized by erythema chronicum migrans and an acute systemic illness. The disease is endemic in many parts of the north-eastern United States. Without treatment, late rheumatic, neurologic, and cardiac complications frequently occur. We report four serologically confirmed cases of Lyme carditis in previously healthy young men (mean age, 45 years) from endemic areas. Each presented with severe symptomatic atrioventricular block, three with episodes of prolonged ventricular asystole. Two had permanent pacemakers implanted (one was later removed), and another, very nearly did, before diagnosis. All four patients were treated with antibiotics, and in each case their rhythm returned to sinus, though one patient has Wenckebach second degree block with atrial pacing at 120 beats/min 16 months later. Carditis occurs in 4% to 10% of cases of Lyme disease and usually begins 3 to 6 weeks after the initial illness. It manifests as a transient myocarditis with varying degrees of atrioventricular block. The diagnosis is made primarily on clinical grounds and confirmed by serologic testing. Temporary cardiac pacing is frequently needed by patients who have severe heart block with hemodynamic instability. The evidence suggests that, in most cases, the block is at the level of the atrioventricular node. The block generally resolves completely with antibiotic treatment. Complete heart block rarely persists more than 1 week and the long-term prognosis appears to be excellent. Consideration and prompt recognition of this potentially lethal, but reversible, cause of heart block is crucial in order to avoid inappropriate permanent pacemaker implantation.

An overview of activities at the Laser Biomedical Research Center

Research projects on laser heating and ablation and on spectroscopy of biological tissues are described. The discussion focuses on studies regarding microscopic laser light scattering of biological cells and structures, ablation of calcific tissue using pulsed HF laser radiation, and fluorescence and its use in diagnosing atherosclerosis. A specifically designed multifiber laser catheter constructed to collect tissue fluorescence spectra using fiber optics is described.

Gas volume quantitation during argon ion laser ablation of atheromatous aorta in blood and 0.9% saline media with an optically shielded catheter

Using an optically shielded fiber optic laser catheter, the amount of gas produced when firing an argon ion laser into 0.9% saline solution or blood alone and into atheromatous aorta in either a blood or 0.9% saline medium was quantitated. Energies from 0.25 to 4 joules (J) were used at powers of 2, 5, and 8 W. We found that total volume of gas produced is small not only at equilibrium (0.3 +/- 0.1 microliter/J when firing in blood alone and also when ablating aorta in blood or saline media) but also at peak (2.5 +/- 0.2 microliters/J firing in blood alone and 1.0 +/- 0.1 microliter/J or 0.9 +/- 0.1 microliter/J when ablating aorta in saline or blood, respectively). Because these volumes are small, a clinically significant event from a gas embolus is unlikely during intravascular laser ablation of atheromatous plaque in the energy and power range studied. No gas was quantitated when firing the argon ion laser into 0.9% saline solution alone. The peak gas volume when firing in blood alone was significantly greater than that produced in the other chamber environments. This is thought to be due to increased absorption of argon laser light by hemoglobin. The gas volumes produced by lasing aorta in 0.9% saline or blood were not statistically different.

Sister-chromatid exchange induction in Chinese hamster ovary cells by 8-methoxypsoralen and brief pulses of laser light: assessment of the relative importance of 8-methoxypsoralen--DNA monoadducts and crosslinks

Brief (less than or equal to 20 nsec) 5-15 mJ pulses of near-ultraviolet laser light were employed to promote, in a controlled manner, the reaction between 8-methoxypsoralen and the DNA of Chinese hamster ovary (CHO) cells. According to Johnston et al. [21], a single brief laser pulse should induce only monoadducts between 8 methoxypsoralen and DNA, while multiple laser pulses are needed to induce 8-methoxypsoralen--DNA crosslinks. In the present study, a single laser pulse was found sufficient to cause a significant elevation in the sister-chromatid exchange (SCE) frequency in CHO cells exposed to 0.75-1.2 X 10(-5) M 8-methoxypsoralen. Additional laser pulses caused less than proportional further increments in SCEs, although the total yield of 8-methoxypsoralen adducts in similarly exposed solutions of isolated DNA increased linearly. Higher numbers of laser pulses induced detectable amounts of 8-methoxypsoralen--DNA crosslinks and distorted the DNA flow histogram of CHO cells in a manner consistent with retarded cell cycle traverse. It is concluded that 8-methoxypsoralen--DNA monoadducts are sufficient to induce SCEs in CHO cells, while 8-methoxypsoralen--DNA crosslinks might have relatively little overall effect on SCE frequencies. These results, together with previous data correlating SCE induction and mutagenesis [10] are discussed in the context of strategies for evaluating psoralen derivatives for their suitability in the phototherapy of skin disorders.

Fibroblast adhesion to fibrinogen and fibrin substrata: requirement for cold-insoluble globulin (plasma fibronectin)

We carried out experiments to determine conditions for fibroblast adhesion to fibrinogen and fibrin substrata. Baby hamster kidney (BHK) cells did not attach to substrata composed of purified fibrinogen or fibrin. When cold-insoluble globulin (CIG) (plasma fibronectin) was bound to fibrinogen or fibrin substrata, adhesion of BHK sells was observed and the extent of adhesion was dependent upon the CIG conecntration. Binding of CIG to fibrinogen or fibrin substrata in the presence of Factor XIII (factor) under covalent crosslinking conditions resulted in a marked increased in the ability of the substrata to support cell adhesion. Control experiments indicated that CIG formed the sites on the fibrinogen and fibrin substrata to which the cells were attaching. In addition, the effect of factor XIII was shown to require covalent crossliking of CIG to the fibrinogen or fibrin, which involved a glutamine residue on the CIG molecule and could be prevented by prior crosslinking of CIG with putrescine or with itself. The enhanced ability of Factor XIII-crosslinked CIG substrata to support cell adhesion could not be accounted for by the absolute amount of CIG bound to the substrata. We present in this paper the possibility that the orientation of CIG on the substrata is the critical factor.

The influence of cold insoluble globulin on platelet morphological response to substrata

Light microscopic studies have been carried out on the attachment and morphological responses of washed human platelets in serum-free medium to fibrinogen-coated, collagen-coated and uncoated tissue culture plastic substrata. Platelets were observed to attach to the substratum, extend filipodia and undergo spreading. Subsequently, lysis of platelets occurred. On uncoated tissue culture plastic substrata, the addition of cold insoluble globulin to the incubations had no effect on the above morphological changes. On the other hand, on the protein coated substrata, there was very little platelet spreading or lysis without the addition of cold insoluble globulin.

Atrial myxoma manifested as cerebral vascular disease

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Diagnosis of gaucher's disease and niemann-pick disease with small samples of venous blood

Enzymes which catalyze the hydrolysis of glucocerebroside and sphingomyelin have been demonstrated in preparations of washed human white blood cells. The level of activity of these respective enzymes is markedly decreased in leukocyte preparations obtained from patients with Gaucher's and Niemann-Pick diseases. Assay of these enzymes may be useful in the differential diagnosis of the sphingolipidoses.