A Viral Protein 4-Based Trivalent Nanoparticle Vaccine Elicited High and Broad Immune Responses and Protective Immunity against the Predominant Rotaviruses

The current live rotavirus (RV) vaccines show reduced effectiveness in developing countries, calling for vaccine strategies with improved efficacy and safety. We generated pseudovirus nanoparticles (PVNPs) that display multiple ectodomains of RV viral protein 4 (VP4), named S-VP4e, as a nonreplicating RV vaccine candidate. The RV spike protein VP4s that bind host receptors and facilitate viral entry are excellent targets for vaccination. In this study, we developed scalable methods to produce three S-VP4e PVNPs, each displaying the VP4e antigens from one of the three predominant P[8], P[4], and P[6] human RVs (HRVs). These PVNPs were recognized by selected neutralizing VP4-specific monoclonal antibodies, bound glycan receptors, attached to permissive HT-29 cells, and underwent cleavage by trypsin between VP8* and VP5*. 3D PVNP models were constructed to understand their structural features. A trivalent PVNP vaccine containing the three S-VP4e PVNPs elicited high and well-balanced VP4e-specific antibody titers in mice directed against the three predominant HRV P types. The resulting antisera neutralized the three HRV prototypes at high titers; greater than 4-fold higher than the neutralizing responses induced by a trivalent vaccine consisting of the S60-VP8* PVNPs. Finally, the trivalent S-VP4e PVNP vaccine provided 90-100% protection against diarrhea caused by HRV challenge. Our data supports the trivalent S-VP4e PVNPs as a promising nonreplicating HRV vaccine candidate for parenteral delivery to circumvent the suboptimal immunization issues of all present live HRV vaccines. The established PVNP-permissive cell and PVNP-glycan binding assays will be instrumental for further investigating HRV-host cell interactions and neutralizing effects of VP4-specific antibodies and antivirals.

Mucosal and systemic neutralizing antibodies to norovirus induced in infant mice orally inoculated with recombinant rotaviruses

Rotaviruses (RVs) preferentially replicate in the small intestine and frequently cause severe diarrheal disease, and the following enteric infection generally induces variable levels of protective systemic and mucosal immune responses in humans and other animals. Rhesus rotavirus (RRV) is a simian RV that was previously used as a human RV vaccine and has been extensively studied in mice. Although RRV replicates poorly in the suckling mouse intestine, infection induces a robust and protective antibody response. The recent availability of plasmid only-based RV reverse genetics systems has enabled the generation of recombinant RVs expressing foreign proteins. However, recombinant RVs have not yet been experimentally tested as potential vaccine vectors to immunize against other gastrointestinal pathogens in vivo. This is a newly available opportunity because several live-attenuated RV vaccines are already widely administered to infants and young children worldwide. To explore the feasibility of using RV as a dual vaccine vector, we rescued replication-competent recombinant RRVs harboring bicistronic gene segment 7 that encodes the native RV nonstructural protein 3 (NSP3) protein and a human norovirus (HuNoV) VP1 protein or P domain from the predominant genotype GII.4. The rescued viruses expressed HuNoV VP1 or P protein in infected cells in vitro and elicited systemic and local antibody responses to HuNoV and RRV following oral infection of suckling mice. Serum IgG and fecal IgA from infected suckling mice bound to and neutralized both RRV and HuNoV. These findings have encouraging practical implications for the design of RV-based next-generation multivalent enteric vaccines to target HuNoV and other human enteric pathogens.

The Role of the VP4 Attachment Protein in Rotavirus Host Range Restriction in an In Vivo Suckling Mouse Model

The basis for rotavirus (RV) host range restriction (HRR) is not fully understood but is likely multigenic. RV genes encoding VP3, VP4, NSP1, NSP2, NSP3, and NSP4 have been associated with HRR in various studies. With the exception of NSP1, little is known about the relative contribution of the other RV genes to HRR. VP4 has been linked to HRR because it functions as the RV cell attachment protein, but its actual role in HRR has not been fully assessed. We generated a collection of recombinant RVs (rRVs) in an isogenic murine-like RV genetic background, harboring either heterologous or homologous VP4 genes from simian, bovine, porcine, human, and murine RV strains, and characterized these rRVs in vitro and in vivo. We found that a murine-like rRV encoding a simian VP4 was shed, spread to uninoculated littermates, and induced diarrhea comparably to rRV harboring a murine VP4. However, rRVs carrying VP4s from both bovine and porcine RVs had reduced diarrhea, but no change in fecal shedding was observed. Both diarrhea and shedding were reduced when VP4 originated from a human RV strain. rRVs harboring VP4s from human or bovine RVs did not transmit to uninoculated littermates. We also generated two rRVs harboring reciprocal chimeric murine or bovine VP4. Both chimeras replicated and caused disease as efficiently as the parental strain with a fully murine VP4. These data suggest that the genetic origin of VP4 partially modulates HRR in the suckling mouse and that both the VP8* and VP5* domains independently contribute to pathogenesis and transmission. IMPORTANCE Human group A rotaviruses (RVs) remain the most important cause of severe acute gastroenteritis among infants and young children worldwide despite the introduction of several safe and effective live attenuated vaccines. The lack of knowledge regarding fundamental aspects of RV biology, such as the genetic basis of host range restriction (HRR), has made it difficult to predictively and efficiently design improved, next-generation live attenuated rotavirus vaccines. Here, we engineered a collection of VP4 monoreassortant RVs to systematically explore the role of VP4 in replication, pathogenicity, and spread, as measures of HRR, in a suckling mouse model. The genetic and mechanistic bases of HRR have substantial clinical relevance given that this restriction forms the basis of attenuation for several replication-competent human RV vaccines. In addition, a better understanding of RV pathogenesis and the determinants of RV spread is likely to enhance our ability to improve antiviral drug and therapy development.

A recombinant murine-like rotavirus with Nano-Luciferase expression reveals tissue tropism, replication dynamics, and virus transmission

Rotaviruses (RVs) are one of the main causes of severe gastroenteritis, diarrhea, and death in children and young animals. While suckling mice prove to be highly useful small animal models of RV infection and pathogenesis, direct visualization tools are lacking to track the temporal dynamics of RV replication and transmissibility in vivo. Here, we report the generation of the first recombinant murine-like RV that encodes a Nano-Luciferase reporter (NLuc) using a newly optimized RV reverse genetics system. The NLuc-expressing RV was replication-competent in cell culture and both infectious and virulent in neonatal mice in vivo. Strong luciferase signals were detected in the proximal and distal small intestines, colon, and mesenteric lymph nodes. We showed, via a noninvasive in vivo imaging system, that RV intestinal replication peaked at days 2 to 5 post infection. Moreover, we successfully tracked RV transmission to uninoculated littermates as early as 3 days post infection, 1 day prior to clinically apparent diarrhea and 3 days prior to detectable fecal RV shedding in the uninoculated littermates. We also observed significantly increased viral replication in Stat1 knockout mice that lack the host interferon signaling. Our results suggest that the NLuc murine-like RV represents a non-lethal powerful tool for the studies of tissue tropism and host and viral factors that regulate RV replication and spread, as well as provides a new tool to facilitate the testing of prophylactic and therapeutic interventions in the future.

The nonstructural p17 protein of a fusogenic bat-borne reovirus regulates viral replication in virus species- and host-specific manners

Nelson Bay orthoreovirus (NBV), a member of the family Reoviridae, genus Orthoreovirus, is a bat-borne virus that causes respiratory diseases in humans. NBV encodes two unique nonstructural proteins, fusion-associated small transmembrane (FAST) protein and p17 protein, in the S1 gene segment. FAST induces cell–cell fusion between infected cells and neighboring cells and the fusogenic activity is required for efficient viral replication. However, the function of p17 in the virus cycle is not fully understood. Here, various p17 mutant viruses including p17-deficient viruses were generated by a reverse genetics system for NBV. The results demonstrated that p17 is not essential for viral replication and does not play an important role in viral pathogenesis. On the other hand, NBV p17 regulated viral replication in a bat cell line but not in other human and animal cell lines. Nuclear localization of p17 is associated with the regulation of NBV replication in bat cells. We also found that p17 dramatically enhances the cell–cell fusion activity of NBV FAST protein for efficient replication in bat cells. Furthermore, we found that a protein homologue of NBV p17 from another bat-borne orthoreovirus, but not those of avian orthoreovirus or baboon orthoreovirus, also supported efficient viral replication in bat cells using a p17-deficient virus-based complementation approach. These results provide critical insights into the functioning of the unique replication machinery of bat-borne viruses in their natural hosts.

Bat-borne viruses including the severe acute respiratory syndrome coronavirus and Nipah virus generally cause highly pathogenic diseases in humans but not in their bat reservoirs. Nelson Bay orthoreovirus (NBV), a bat-borne virus associated with acute respiratory tract infections in humans, possesses two unique nonstructural proteins, FAST and p17. FAST enhances viral replication through its cell–cell fusion activity, while the function of p17 in the viral life cycle is poorly understood. In this study, we show that p17 is non-essential for viral replication in several human and animal cell lines and does not play a critical role in pathogenesis in vivo. However, p17 localizes to the nucleus and regulates viral replication specifically in cells derived from bats by enhancing the cell–cell fusion activity of FAST in a host-specific manner. Furthermore, the expression of NBV p17 or an NBV p17 homologue from another bat-borne orthoreovirus enhanced the replication of an NBV mutant deficient in p17 in bat cells, suggesting that the function of p17 is virus species-specific. These findings will contribute to our understanding of how the replication of viruses is regulated in their natural reservoirs.

The Detection of Rotavirus Antigenemia by Immunochromatographic Kits: a Case Series

BACKGROUND

Acute gastroenteritis is the most common cause of illness and death in infants and young children worldwide. Rotaviruses (RVs) are the major viruses that cause acute gastroenteritis in young children, especially in developing countries in Asia and Africa.

METHODS

The presence of rotavirus antigens in sera of four unvaccinated pediatric patients, aged between 4 and 6 years with severe diarrhea and dehydration, were detected by using three immunochromatographic (IC) kits. In addition, the presence of anti-rotavirus IgG, IgA, and IgM antibodies and their concentrations in patient sera were also determined by enzyme immunoassay (EIA).

RESULTS

All three kits could detect rotavirus antigen in patient sera with different intensity of the test lines. When patient sera were pretreated with anti-VP6 rotavirus mouse monoclonal antibody prior to testing, the rotavirus positive test lines disappeared, suggesting that all patient sera contained VP6 protein antigen of rotavirus. Assessment of antibody concentration in these patient sera revealed that all patient sera contained IgG, IgA, and IgM antibodies against rotavirus antigen at different concentrations.

CONCLUSIONS

The sensitivity of rotavirus protein detection in the patient sera of one IC kit brand was comparable to those of the EIA, suggesting this IC kit could be an alternative screening method for rapid diagnosis of rotavirus infection.

DsRNA Sequencing for RNA Virus Surveillance Using Human Clinical Samples

Although viruses infect various organs and are associated with diseases, there may be many unidentified pathogenic viruses. The recent development of next-generation sequencing technologies has facilitated the establishment of an environmental viral metagenomic approach targeting the intracellular viral genome. However, an efficient method for the detection of a viral genome derived from an RNA virus in animal or human samples has not been established. Here, we established a method for the efficient detection of RNA viruses in human clinical samples. We then tested the efficiency of the method compared to other conventional methods by using tissue samples collected from 57 recipients of living donor liver transplantations performed between June 2017 and February 2019 at Kyushu University Hospital. The viral read ratio in human clinical samples was higher by the new method than by the other conventional methods. In addition, the new method correctly identified viral RNA from liver tissues infected with hepatitis C virus. This new technique will be an effective tool for intracellular RNA virus surveillance in human clinical samples and may be useful for the detection of new RNA viruses associated with diseases.

Generation of recombinant rotaviruses encoding a split NanoLuc peptide tag

Recombinant viruses expressing fluorescent or luminescent reporter proteins are used to quantitate and visualize viral replication and transmission. Here, we used a split NanoLuc luciferase (NLuc) system comprising large LgBiT and small HiBiT peptide fragments to generate stable reporter rotaviruses (RVs). Reporter RVs expressing NSP1-HiBiT fusion protein were generated by placing an 11 amino acid HiBiT peptide tag at the C-terminus of the intact simian RV NSP1 open reading frame or truncated human RV NSP1 open reading frame. Virus-infected cell lysates exhibited NLuc activity that paralleled virus replication. The antiviral activity of neutralizing antibodies and antiviral reagents against the recombinant HiBiT reporter viruses were monitored by measuring reductions in NLuc expression. These findings demonstrate that the HiBiT reporter RV systems are powerful tools for studying the viral life cycle and pathogenesis, and a robust platform for developing novel antiviral drugs.

Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions

The PHENIX collaboration presents first measurements of low-momentum (0.4<p_{T}<3  GeV/c) direct-photon yields from Au+Au collisions at sqrt[s_{NN}]=39 and 62.4 GeV. For both beam energies the direct-photon yields are substantially enhanced with respect to expectations from prompt processes, similar to the yields observed in Au+Au collisions at sqrt[s_{NN}]=200. Analyzing the photon yield as a function of the experimental observable dN_{ch}/dη reveals that the low-momentum (>1  GeV/c) direct-photon yield dN_{γ}^{dir}/dη is a smooth function of dN_{ch}/dη and can be well described as proportional to (dN_{ch}/dη)^{α} with α≈1.25. This scaling behavior holds for a wide range of beam energies at the Relativistic Heavy Ion Collider and the Large Hadron Collider, for centrality selected samples, as well as for different A+A collision systems. At a given beam energy, the scaling also holds for high p_{T} (>5  GeV/c), but when results from different collision energies are compared, an additional sqrt[s_{NN}]-dependent multiplicative factor is needed to describe the integrated-direct-photon yield.

Cell-cell fusion induced by reovirus FAST proteins enhances replication and pathogenicity of non-enveloped dsRNA viruses

Fusogenic reoviruses encode fusion-associated small transmembrane (FAST) protein, which induces cell-cell fusion. FAST protein is the only known fusogenic protein in non-enveloped viruses, and its role in virus replication is not yet known. We generated replication-competent, FAST protein-deficient pteropine orthoreovirus and demonstrated that FAST protein was not essential for viral replication, but enhanced viral replication in the early phase of infection. Addition of recombinant FAST protein enhanced replication of FAST-deficient virus and other non-fusogenic viruses in a fusion-dependent and FAST-species-independent manner. In a mouse model, replication and pathogenicity of FAST-deficient virus were severely impaired relative to wild-type virus, indicating that FAST protein is a major determinant of the high pathogenicity of fusogenic reovirus. FAST-deficient virus also conferred effective protection against challenge with lethal homologous virus strains in mice. Our results demonstrate a novel role of a viral fusogenic protein and the existence of a cell-cell fusion-dependent replication system in non-enveloped viruses.

Lethal murine infection model for human respiratory disease-associated Pteropine orthoreovirus

Pteropine orthoreovirus (PRV) is an emerging bat-borne human pathogen causing severe respiratory illness. To date, however, the evaluation of PRV virulence has largely depended on the limited numbers of clinical cases owing to the lack of animal models. To develop an in vivo model of PRV infection, an inbred C3H mouse strain was infected intranasally with pathogenic PRV strain Miyazaki-Bali/2007. C3H mice suffered severe lung infection with significant body weight reduction and died within 7 days after intranasal infection. Infectious viruses were isolated mainly from the lungs and trachea. Histopathological examination revealed interstitial pneumonia with monocytes infiltration. Following repeated intranasal infection, mice developed antibodies to particular structural and non-structural proteins of PRV. The results of these immunological assays will help to develop laboratory protocols for sero-epidemiological studies. Our small rodent model of lethal respiratory infection will further allow investigation of the molecular mechanisms underlying the high pathogenicity of PRV.

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A lethal PRV strain Miyazaki-Bali/2007 murine infection model was established.

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Susceptibility of different mouse strains to PRV infection was investigated.

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Antibody responses to PRV proteins in C3H mice post intranasal infection were studied.

Parathyroid hormone secretion in diabetes mellitus

To investigate the parathyroid function in diabetes mellitus, we performed an oral phosphate load in 6 diabetic patients and 6 nondiabetic subjects without renal failure (serum creatinine less than 1.5 mg/dl). Each subject received a total of 2.0 g of phosphate daily per os on 5 consecutive days. Blood and urine samples were obtained daily before and 2 h after the administration of phosphate in the morning. All subjects responded with a similar increase in the serum phosphorus concentration and fall in the ionized calcium concentration. Intact parathyroid hormone levels rose by 2.6-fold in the control subjects but by less than 1.5-fold in the diabetic subjects. It was concluded that hyporesponsiveness of the parathyroid hormone to phosphate administration was found in the diabetic patients without renal failure.

A plasmid-based reverse genetics system for mammalian orthoreoviruses driven by a plasmid-encoded T7 RNA polymerase

Mammalian orthoreoviruses (reoviruses) have served as highly useful models for studies of virus replication and pathogenesis. The development of a plasmid-based reverse genetics system represented a major breakthrough in reovirus research. The current reverse genetics systems for reoviruses rely on the expression of T7 RNA polymerase within cells transfected with reovirus gene-segment cDNA plasmids. In these systems, the T7 RNA polymerase is provided by using a recombinant vaccinia virus expressing T7 RNA polymerase or a cell line constitutively expressing T7 RNA polymerase. Here, we describe an alternative plasmid-based rescue system driven by a plasmid-encoded T7 RNA polymerase, which could increase the flexibility of such reverse genetics systems. Although this approach requires transfection of an additional plasmid, virus recovery was achieved when A549, BHK-21, or L929 cells were co-transfected with a reovirus 10-plasmid set together with a plasmid encoding T7 RNA polymerase. Theoretically, this system offers the possibility to generate reoviruses in any cell line, including those amenable to propagation of viral vectors for clinical use. Thus, this approach will increase the flexibility of reverse genetics for basic studies of reovirus biology and foster development of reoviruses for clinical applications.

Natural infection of cynomolgus monkeys with dengue virus occurs in epidemic cycles in the Philippines

To investigate the potential role of non-human primates (NHPs) in a dengue virus (DENV) epidemic, we conducted serological and genomic studies using plasma samples collected from 100 cynomolgus monkeys (Macaca fascicularis) in an animal breeding facility in the Philippines. An ELISA revealed 21 monkeys with a positive IgM reaction and 19 positive for IgG. Five of the monkeys were positive for both IgM and IgG. Of the 21 IgM-positive samples, a neutralization assay identified seven containing DENV-specific antibodies. We amplified the viral non-structural 1 (NS1) gene in two and the envelope (E) gene in one of these seven samples by RT-PCR. Phylogenetic analyses revealed that these DENV genes belonged to the epidemic DENV-2 family, not the sylvatic DENV family. These results suggest that NHPs may serve as a reservoir of epidemic DENV; therefore, the ecology of the urban DENV infection cycle should be investigated in these animals in detail.

Measurement of direct photons in Au+Au collisions at √(s(NN))=200 GeV

We report the measurement of direct photons at midrapidity in Au+Au collisions at √(s(NN))=200 GeV. The direct photon signal was extracted for the transverse momentum range of 4 GeV/c<p(T)<22 GeV/c, using a statistical method to subtract decay photons from the inclusive photon sample. The direct photon nuclear modification factor R(AA) was calculated as a function of p(T) for different Au+Au collision centralities using the measured p+p direct photon spectrum and compared to theoretical predictions. R(AA) was found to be consistent with unity for all centralities over the entire measured p(T) range. Theoretical models that account for modifications of initial direct photon production due to modified parton distribution functions in Au and the different isospin composition of the nuclei predict a modest change of R(AA) from unity. They are consistent with the data. Models with compensating effects of the quark-gluon plasma on high-energy photons, such as suppression of jet-fragmentation photons and induced-photon bremsstrahlung from partons traversing the medium, are also consistent with this measurement.

Enhanced production of direct photons in Au + Au collisions at square root(S(NN)) = 200 GeV and implications for the initial temperature

The production of e+ e- pairs for m(e+ e-)<0.3 GeV/c2 and 1<p(T)<5 GeV/c is measured in p+p and Au+Au collisions at square root(S(NN))=200 GeV. An enhanced yield above hadronic sources is observed. Treating the excess as photon internal conversions, the invariant yield of direct photons is deduced. In central Au+Au collisions, the excess of the direct photon yield over p+p is exponential in transverse momentum, with an inverse slope T=221+/-19(stat)+/-19(syst) MeV. Hydrodynamical models with initial temperatures ranging from T(init) approximately 300-600 MeV at times of approximately 0.6-0.15 fm/c after the collision are in qualitative agreement with the data. Lattice QCD predicts a phase transition to quark gluon plasma at approximately 170 MeV.

Charged Kaon interferometric probes of space-time evolution in Au+Au collisions at sqrt[S(NN)]=200 GeV

Bose-Einstein correlations of charged kaons are used to probe Au+Au collisions at sqrt[S(NN)]=200 GeV and are compared to charged pion probes, which have a larger hadronic scattering cross section. Three-dimensional Gaussian source radii are extracted, along with a one-dimensional kaon emission source function. The centrality dependences of the three Gaussian radii are well described by a single linear function of N(part)1/3 with a zero intercept. Imaging analysis shows a deviation from a Gaussian tail at r greater than or approximately equal to 10 fm, although the bulk emission at lower radius is well described by a Gaussian. The presence of a non-Gaussian tail in the kaon source reaffirms that the particle emission region in a heavy-ion collision is extended, and that similar measurements with pions are not solely due to the decay of long-lived resonances.

Suppression pattern of neutral pions at high transverse momentum in Au + Au collisions at sqrt[sNN]=200 GeV and constraints on medium transport coefficients

For Au + Au collisions at 200 GeV, we measure neutral pion production with good statistics for transverse momentum, pT, up to 20 GeV/c. A fivefold suppression is found, which is essentially constant for 5 < pT < 20 GeV/c. Experimental uncertainties are small enough to constrain any model-dependent parametrization for the transport coefficient of the medium, e.g., q in the parton quenching model. The spectral shape is similar for all collision classes, and the suppression does not saturate in Au + Au collisions.

Particle-species dependent modification of jet-induced correlations in Au+Au collisions at sqrt[s_{NN}]=200 GeV

Measurements in Au+Au collisions at sqrt[s_{NN}]=200 GeV of jet correlations for a trigger hadron at intermediate transverse momentum (p_{T,trig}) with associated mesons or baryons at lower p_{T,assoc} indicate strong modification of the away-side jet. The ratio of jet-associated baryons to mesons increases with centrality and p_{T,assoc}. For the most central collisions, the ratio is similar to that for inclusive measurements. This trend is incompatible with in-vacuum fragmentation but could be due to jetlike contributions from correlated soft partons, which recombine upon hadronization.

Source breakup dynamics in Au + Au collisions at sqrt[s(NN)]=200 GeV via three-dimensional two-pion source imaging

A three-dimensional correlation function obtained from midrapidity, low p(T), pion pairs in central Au+Au collisions at sqrt[s(NN)]=200 GeV is studied. The extracted model-independent source function indicates a long range tail in the directions of the pion pair transverse momentum (out) and the beam (long). A proper breakup time tau(0) ~ 9 fm/c and a mean proper emission duration Delta tau ~ 2 fm/c, leading to sizable emission time differences ({|Delta t(LCM)|} approximately 12 fm/c), are required to allow models to be successfully matched to these tails. The model comparisons also suggest an outside-in "burning" of the emission source reminiscent of many hydrodynamical models.

Elliptic flow for phi mesons and (anti)deuterons in Au+Au collisions at square root of sNN=200 GeV

Differential elliptic flow (v(2)) for phi mesons and (anti)deuterons (d)d is measured for Au+Au collisions at square root of sNN=200 GeV. The v(2) for phi mesons follows the trend of lighter pi+/- and K+/- mesons, suggesting that ordinary hadrons interacting with standard hadronic cross sections are not the primary driver for elliptic flow development. The v(2) values for (d)d suggest that elliptic flow is additive for composite particles. This further validation of the universal scaling of v(2) per constituent quark for baryons and mesons suggests that partonic collectivity dominates the transverse expansion dynamics.

Total synthesis of (+/-)-clavubicyclone

[reaction: see text] The total synthesis of racemic clavubicyclone (1), which was isolated from Okinawan soft coral by our group, is described. The bicyclo[3.2.1]octane skeleton was prepared by Cope rearrangement of a divinylcyclopropane derivative. Three functional groups on the skeleton were constructed by Barton decarboxylation, Wittig reaction, and alkylation.

System size and energy dependence of jet-induced hadron pair correlation shapes in Cu+Cu and Au+Au collisions at square root sNN=200 and 62.4 GeV

We present azimuthal angle correlations of intermediate transverse momentum (1-4 GeV/c) hadrons from dijets in Cu+Cu and Au+Au collisions at square root sNN=62.4 and 200 GeV. The away-side dijet induced azimuthal correlation is broadened, non-Gaussian, and peaked away from Delta phi=pi in central and semicentral collisions in all the systems. The broadening and peak location are found to depend upon the number of participants in the collision, but not on the collision energy or beam nuclei. These results are consistent with sound or shock wave models, but pose challenges to Cherenkov gluon radiation models.

J/psi production versus centrality, transverse momentum, and rapidity in Au+Au collisions at square root sNN=200 GeV

The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured J/psi production for rapidities -2.2<y<2.2 in Au+Au collisions at square root sNN=200 GeV. The J/psi invariant yield and nuclear modification factor RAA as a function of centrality, transverse momentum, and rapidity are reported. A suppression of J/psi relative to binary collision scaling of proton-proton reaction yields is observed. Models which describe the lower energy J/psi data at the CERN Super Proton Synchrotron invoking only J/psi destruction based on the local medium density predict a significantly larger suppression at RHIC and more suppression at midrapidity than at forward rapidity. Both trends are contradicted by our data.

Scaling properties of azimuthal anisotropy in Au+Au and Cu+Cu Collisions at sqrt[s NN]=200 GeV

Differential measurements of elliptic flow (v2) for Au+Au and Cu+Cu collisions at sqrt[sNN]=200 GeV are used to test and validate predictions from perfect fluid hydrodynamics for scaling of v2 with eccentricity, system size, and transverse kinetic energy (KE T). For KE T identical with mT-m up to approximately 1 GeV the scaling is compatible with hydrodynamic expansion of a thermalized fluid. For large values of KE T mesons and baryons scale separately. Quark number scaling reveals a universal scaling of v2 for both mesons and baryons over the full KE T range for Au+Au. For Au+Au and Cu+Cu the scaling is more pronounced in terms of KE T, rather than transverse momentum.

Saturation of azimuthal anisotropy in Au + Au collisions at (square root)s(NN) = 62-200 GeV

New measurements are presented for charged hadron azimuthal correlations at midrapidity in Au+Au collisions at (square root)s(NN) = 62.4 and 200 GeV. They are compared to earlier measurements obtained at (square root)s(NN) = 130 GeV and in Pb + Pb collisions at (square root)s(NN) = 17.2 GeV. Sizeable anisotropies are observed with centrality and transverse momentum (pT) dependence characteristic of elliptic flow (upsilon2). For a broad range of centralities, the observed magnitudes and trends of the differential anisotropy, upsilon2(pT), change very little over the collision energy range (square root)s(NN) = 62-200 GeV, indicating saturation of the excitation function for upsilon2 at these energies. Such a saturation may be indicative of the dominance of a very soft equation of state for (square root)s(NN) approximately 60-200 GeV.

Femoral artery wall thickness and stiffness in evaluation of peripheral vascular disease in type 2 diabetes mellitus

Stiffening and thickening of arterial wall are two important components of atherosclerosis. The purpose of this study was to evaluate the effects of femoral artery wall stiffness on clinical manifestation of peripheral vascular disease (PVD) in type 2 diabetes mellitus. The subjects were 315 patients with type 2 diabetes. Presence of intermittent claudication and/or leg pain at rest and reduced ankle-brachial blood pressure index (ABI<0.9) were used as a subjective and an objective index of PVD, respectively. Femoral artery intima-media thickness (FA-IMT) and stiffness parameter beta (FA-stiffness beta) were measured by ultrasound methods. Symptomatic patients (N=58) showed greater values for both FA-IMT and FA-stiffness beta than those without symptom (N=257). Similarly, patients with reduced ABI (N=56) had greater FA-IMT and FA-stiffness beta than those without (N=259). However, correlation between FA-IMT and FA-stiffness beta was not impressive, especially in the symptomatic patients. To evaluate the effect of FA-stiffness beta on PVD symptoms, the subjects were divided into three subgroups according to FA-IMT, and then FA-stiffness beta was compared between those with and without PVD symptoms in each subgroup. The symptomatic patients had greater FA-stiffness beta values than the asymptomatic subjects in all the three subgroups. Multiple logistic regression analysis indicated that the presence of PVD symptoms was associated more closely with increased FA-stiffness beta than with increased FA-IMT, whereas reduced ABI was associated more closely with FA-IMT than with FA-stiffness beta. These data suggest that stiffening of arterial wall has a significant impact on PVD manifestations, particularly on the leg symptoms, in patients with type 2 diabetes.

Atherogenic lipoprotein changes in diabetic nephropathy

Cardiovascular risk is increased in patients with diabetic nephropathy. The aim of this study was to examine the relative impacts of albuminuria and renal failure, the two important features of diabetic nephropathy, on potentially atherogenic lipoprotein changes in this condition. The subjects were 160 non-diabetic healthy controls and a total of 200 type 2 diabetes patients with various degrees of nephropathy. The diabetic patients were divided into four groups by urinary albumin/creatinine ratio (U-ACR) and serum creatinine (S-Cr) levels: DM-1 (U-ACR< 30 mg/g, N=85), DM-2 (U-ACR=30-300 mg/g, N=48), DM-3 (U-ACR > 300 mg/g, N=29) and DM-4 (S-Cr>177 micromol/l or 2.0mg/dl, N=38). Lipids in very low (VLDL), intermediate (IDL), low (LDL), and high density (HDL) lipoproteins were measured following ultracentrifugation. VLDL-cholesterol (VLDL-C) was elevated (by 73-100%) in diabetic patients and it did not differ among the stages of nephropathy. IDL-C was higher as the nephropathy stage was advanced, and the elevation was significant in the DM-3 (by 75%) and DM-4 (by 131%) groups. LDL-C was not elevated in diabetic patients and was not different among the stages of nephropathy. Reduction of HDL-C was significant in DM-1, DM-2 and DM-3 (by 12-16%) and it was more exaggerated in DM-4 (by 35%). Multiple regression analyses indicated that elevated S-Cr, but not U-ACR, was an independent factor associated with raised IDL-C and lowered HDL-C in diabetic patients. These results indicate that diabetic patients with nephropathy show multiple lipoprotein changes, and that renal failure has greater impact than albuminuria on abnormalities in IDL and HDL. These lipoprotein alterations may contribute to an increased cardiovascular risk in diabetic nephropathy, especially in diabetic renal failure.

Impact of insulin resistance and nephropathy on homocysteine in type 2 diabetes

OBJECTIVE

To assess the impacts of insulin resistance and renal function on plasma total homocysteine (tHcy) levels in patients with type 2 diabetes with a wide range of nephropathy.

RESEARCH DESIGN AND METHODS

Plasma tHcy levels were measured using the enzyme immunoassay method in 75 patients with type 2 diabetes and compared with those in 54 healthy control subjects. Insulin sensitivity indexes were assessed in patients with type 2 diabetes by hyperinsulinemic-euglycemic clamp using artificial pancreas.

RESULTS

Plasma tHcy levels and their log-translormed values (log tHcy) were significantly higher in all patients with diabetes than in control subjects (tHcy, 12.0 +/- 0.7 [SE] vs. 8.7 +/- 0.3 micromol/l, P < 0.0001; log tHcy, 1.040 +/- 0.021 vs. 0.920 +/- 0.016 micromol/l, P < 0.0001). Plasma tHcy levels in patients with diabetes were significantly increased according to degree of nephropathy (P < 0.0001). On simple regression analyses, log tHcy correlated with insulin sensitivity indexes (r = -0.319, P = 0.005) as well as creatinine clearance (r = 0.634, P < 0.0001) in all patients with diabetes. Multiple regression analyses showed that insulin sensitivity indexes (beta = -0.245) as well as creatinine clearance were independent contributors to log tHcy in all patients with diabetes (R2 = 0.750, P < 0.0001). For the 59 patients with diabetes with creatinine clearance >60 ml/min, insulin sensitivity indexes were also shown to be a significant contributor to log tHcy (beta = -0.438, R2 = 0.561, P < 0.001).

CONCLUSION

Insulin resistance and renal function are independent determinants of tHcy levels in patients with type 2 diabetes.

Predominant inner-half wall thickening of left ventricle is attenuated in dilated cardiomyopathy: an application of tissue Doppler tracking technique

The importance of the inner half (IH) of the left ventricular (LV) wall has been reported in hearts that contract normally. However, it is difficult to verify this fact in an in vivo human heart with clinical echocardiography. By using a recently developed tissue Doppler tracking technique, we could assess the systolic wall thickening of the IH and outer half (OH) of the LV wall in 11 normal and 7 dilated cardiomyopathic hearts. Percent wall thickening and the fractional contribution of the IH and OH to the transmural wall thickening were calculated. In healthy subjects, percent wall thickening of the IH, OH, and transmural wall of the left ventricle were 75.8% +/- 24.1%, 39.4% +/- 14.4% (P <.001 versus IH), and 57.6% +/- 17.6%, respectively. In patients with dilated cardiomyopathy, those values were 31.3% +/- 17.1%, 31.2% +/- 20.1% (not significant versus IH), and 31.2% +/- 16.5%, respectively. On the other hand, the fractional contributions of the IH and OH were 66.2% +/- 7.7% and 33.8% +/- 7.7% (P &lt.01 versus IH) in healthy subjects and 50.5% +/- 11.8% and 49.5% +/- 11.8% (not significant versus IH) in patients with dilated cardiomyopathy. Specifically, the IH contributed to the transmural wall thickening nearly twice as much as the OH did in healthy subjects, however, the predominance of IH contribution was attenuated in dilated cardiomyopathy. The tissue Doppler tracking technique is useful in assessing the IH and OH LV wall thickening separately in the clinical situation.

Increased retinal blood flow in patients with Graves' disease: influence of thyroid function and ophthalmopathy

OBJECTIVE

Graves' ophthalmopathy (GO), resulting from the inflammation of retro-orbital tissue, is one of the major complications of Graves' disease (GD). We investigated the clinical usefulness of the measurement of retinal blood flow (RBF) in the evaluation of GO and its activity.

MEASUREMENT

RBF was quantitated by pulsed Doppler mode at just below the branch of central retinal artery, from which the resistance index (RI) was calculated.

PATIENTS

Forty-seven euthyroid GD patients and 70 gender- and age-matched normal controls were measured for RI to investigate the effect of GO on RBF. To investigate the effect of hyperthyroidism, 20 GD patients were measured for RI changes during antithyroid drug (ATD) therapy. Furthermore, 17 GD patients with clinically overt GO were measured for RI changes during treatment with glucocorticoid plus retro-orbital radiation.

RESULTS

RI and exophthalmos showed a significant positive correlation in 47 treated euthyroid GD patients without clinically overt GO (r=0.307, P<0.05), but not in 70 age- and sex-matched normal subjects (r=0.185, P=0.161). Furthermore, RI, but not exophthalmos, significantly correlated with serum TSH receptor antibodies, an indicator for the disease activity of GO. ATD therapy significantly reduced RI in GD patients from 0.719+/-0.041 in the hyperthyroid state to 0.661+/-0.051 in the euthyroid state, but not to the levels observed in normal subjects having the similar exophthalmos (0.640+/-0.049). The fractional reduction of RI during ATD therapy significantly correlated with those of pulse pressure and ultrasonographic distensibility in carotid artery, but not with those of serum vascular injury markers. In 17 GD patients with clinically overt GO, all four patients having adipose tissue enlargement but not extraocular muscle hypertrophy (inactive GO) showed RI within the mean +/- 1 s.d. for treated GD patients without GO. In the other 13 GD patients having extraocular muscle hypertrophy (active GO), four and eight patients showed RI outside mean +/- 2 s.d. and mean +/- 1 s.d. respectively. Treatment with glucocorticoid plus radiation moved RI in 8 out of 10 patients toward the mean values of GD patients without GO, in spite of little improvement of exophthalmos.

CONCLUSIONS

It was suggested that GD patients showed altered retinal hemodynamics, possibly resulting either from the cardiovascular effect of hyperthyroidism or from retro-orbital inflammation, particularly in extraocular muscle.

Secondary hyperparathyroidism, decreased hepatic triglyceride lipase, elevated intermediate density lipoprotein and atherosclerosis in hemodialysis patients

Cardiovascular mortality is higher in dialysis patients than the nonuremic population. This has been taken to indicate that dialysis patients have accelerated atherosclerosis [1]. We have recently revealed that atherosclerosis in hemodialysis patients is advanced morphologically, showing a greater intima media thickness in the carotid and femoral arteries in dialysis patients than healthy control subjects by high-resolution B mode ultrasonography [2]. Lipoprotein abnormality is one of the major risk factors for atherosclerosis in the general population, and recent studies [3–6] reemphasize the importance of triglyceride-rich lipoproteins such as partially lipolyzed very low density lipoprotein (VLDL) and intermediate density lipoprotein (IDL). These lipoprotein classes are significantly elevated in patients with chronic renal failure [7–9].

Relationship between urinary albumin excretion and glomerular filtration rate in normotensive, nonproteinuric patients with type 2 diabetes mellitus

BACKGROUND/AIM

In patients with type 2 diabetes mellitus, the relationship between glomerular filtration rate (GFR) and urinary albumin excretion remains an unresolved issue. In order to investigate the early renal function abnormalities, GFR and urinary albumin excretion were assessed, and their relationship was examined in normotensive patients with type 2 diabetes mellitus.

METHODS

In a cross-sectional study of 85 nonhypertensive Japanese patients with type 2 diabetes mellitus not showing overt proteinuria, the GFR was measured using (99m)Tc-diethylenetriamine pentaacetate renography. Fifty-one diabetic patients lacked microalbuminuria (albumin excretion <30 mg/day), while 34 patients showed microalbuminuria (between 30 and 300 mg/day). Fifteen healthy subjects served as controls.

RESULTS

The three groups were well matched with regard to gender, age, and body mass index. The GFR in microalbuminuric patients (134 +/- 23 ml/min/1.48 m(2)) was significantly higher than in patients without microalbuminuria (108 +/- 21 ml/min/1.48 m(2)) and in controls (109 +/- 18 ml/min/1.48 m(2); p < 0.0001). In type 2 diabetic patients, the GFR positively correlated with the logarithmically transformed urinary albumin excretion. Multiple regression analysis showed that the urinary albumin excretion was significantly and independently affected by GFR (beta = 0.548), duration of diabetes (beta = 0.297), and systolic blood pressure (beta = 0.232; R(2) = 0.409; p < 0.0001).

CONCLUSION

It is suggested that one of the mechanisms underlying increased urinary albumin excretion in early nephropathy in normotensive type 2 diabetes is glomerular hyperfiltration.

Diabetes mellitus worsens intrarenal hemodynamic abnormalities in nondialyzed patients with chronic renal failure

Duplex Doppler sonography has been reported to be useful in examining the intrarenal hemodynamic abnormalities in various renal diseases. We investigated the impact of diabetes on intrarenal hemodynamics in patients with chronic renal failure (CRF). The resistive index and pulsatility index of the renal interlobar arteries were measured using duplex Doppler sonography in 90 CRF patients (serum creatinine >130 and <800 mmol/l, mean age 59 +/- 11 years). Forty-eight patients had type 2 diabetes and 42 did not. Twenty-nine age-matched, healthy subjects served as controls. Both resistive index and pulsatility index were greater in CRF patients than in the controls (p < 0.0001). No significant differences existed in age, sex, body mass index, total serum cholesterol, serum creatinine, estimated creatinine clearance, or mean blood pressure between the diabetic CRF and nondiabetic CRF groups. Resistive index and pulsatility index were significantly increased in the diabetic CRF patients compared to the nondiabetic CRF patients (p < 0.0001). Multiple regression analysis of all CRF patients revealed that resistive index was independently affected by the presence of type 2 diabetes (F = 44.535), as well as decreased creatinine clearance (F = 18.157) and age (F = 15.160) (R(2) = 0.559, p < 0.0001). These results clearly demonstrated that intrarenal arterial resistance is significantly increased in CRF patients with type 2 diabetes compared to similar patients without diabetes. The impact of diabetes mellitus and advanced age on intrarenal hemodynamics may be due to intrarenal arteriosclerosis and interstitital lesions. Measurements of RI values in addition to conventional ultrasound imaging may add further information on such renal lesions.

Hyperparathyroidism is augmented by ovariectomy in Nagase analbuminemic rats

The role of albumin in bone metabolism was studied in Nagase analbuminemic (NA) rats. Serum calcium (Ca), inorganic phosphate (Pi) and magnesium (Mg) concentrations did not differ between female NA and control Sprague-Dawley (SD) rats at the time of ovariectomy (ovx), although serum ionized Ca was significantly lower in NA rats than in SD rats. Serum parathyroid hormone (PTH) and osteocalcin (OC) concentrations and urinary Ca excretion were significantly greater in NA rats than in SD rats, suggesting hyperparathyroidism and the resultant enhanced bone turnover in NA rats. Paradoxically, ovx increased serum PTH and OC in NA rats but not in SD rats. Ovx-induced exacerbation of hyperparathyroidism was confirmed by significantly greater conversion of 25-hydroxyvitamin D to 1, 25-dihydroxyvitamin D in ovx NA rats even after normalization to vitamin D-binding protein. Bone mineral density (BMD) in proximal tibia increased similarly in a time-dependent manner in sham-operated NA and SD rats. However, ovx ablated the time-dependent increase of BMD in SD rats and significantly decreased BMD in NA rats by 2 wk after ovx, resulting in a significantly lower BMD in ovx NA rats than in ovx SD rats. In summary, NA rats, which are analbuminemic with compensatory increases in lipid and protein synthesis, developed hyperparathyroidism, possibly due to an increase in serum Pi and a reduction of ionized Ca, and ovx induced a greater BMD reduction in NA rats than in SD rats, probably by exacerbating hyperparathyroidism.

Renal dysfunction worsened by superimposition of IgA glomerulonephritis in a patient with overt diabetic nephropathy

The combination of glomerulonephritis and diabetes nephropathy has been reported to occur in 1.8–22% of biopsy-proven diabetic nephropathy cases [1–6]. In these reports, however, the onset of glomerulonephritis during the course of diabetic nephropathy was not described in detail, and how the superimposition of glomerulonephritis affected renal function, particularly at the advanced stage of diabetic nephropathy. We recently encountered a patient, in whom the onset of IgA glomerulonephritis was detected clinically during the advanced stage of overt diabetic nephropathy. In this case, the onset of glomerulonephritis significantly increased the progressive deterioration of renal function.

Antibodies against oxidized LDL and carotid artery intima-media thickness in a healthy population

Oxidation of LDLs plays an important role in atherosclerosis, and immune response to oxidized LDL (oxLDL) may modulate atherogenesis. Although immunization with oxLDL is shown to suppress atherogenesis in animal models, the role of the immune response to oxLDL is not well established in humans. We investigated the relationship between the titer of anti-oxLDL antibody (oxLDL Ab) and arterial wall thickness in a healthy population with no clinical signs of atherosclerosis. Intima-media thickness of the carotid arteries (CA-IMT) was measured by high-resolution B-mode ultrasonography in 446 healthy subjects. The titer of IgG-class oxLDL Ab was measured by a solid-phase ELISA. In univariate analysis, CA-IMT correlated positively with age, systolic blood pressure, total cholesterol, triglyceride, LDL cholesterol, body mass index, and waist-to-hip ratio, whereas it correlated negatively with HDL cholesterol and oxLDL Ab titer. The inverse association between oxLDL Ab titer and CA-IMT remained significant in multiple regression analysis, which took other confounding variables into account. These results indicate an independent inverse relationship between oxLDL Ab titer and CA-IMT in healthy subjects, supporting the hypothesis that immune response to oxLDL may have a protective role at an early stage of human atherosclerosis.

Inverse relationship between circulating oxidized low density lipoprotein (oxLDL) and anti-oxLDL antibody levels in healthy subjects

Oxidized low density lipoprotein (oxLDL) has been implicated in the pathogenesis of atherosclerosis. Recent studies have shown that immunization of animals with oxLDL results in suppression of atherogenesis. Antibody against oxLDL (oxLDL Ab) is detectable in human sera, although its biological significance is not well established. We examined the relationship between oxLDL Ab titer and circulating oxLDL level in 130 healthy Japanese subjects. OxLDL was measured as apolipoprotein (apo) B-containing lipoproteins carrying oxidized phosphatidylcholines by a sensitive ELISA. IgG class oxLDL Ab titer was measured by ELISA. Plasma oxLDL concentration was very low and it corresponded on average to one to two out of 1000 apoB-containing lipoproteins in plasma. Plasma oxLDL correlated positively with LDL cholesterol and inversely with oxLDL Ab titer. These associations remained significant and independent in multiple regression analysis including age, gender, smoking, and high-density lipoprotein cholesterol. These data indicate that healthy subjects have a very low concentration of oxLDL in the circulation, and that oxLDL Ab titer is in an inverse relationship with plasma oxLDL concentration in this population. Although these results suggest that oxLDL Ab may play a role in maintaining the low level of plasma oxLDL, its role in atherogenesis awaits further studies.

Association of ACE gene polymorphism with arterial stiffness in patients with type 2 diabetes

OBJECTIVE

To assess the relationship between the insertion (I)/deletion (D) polymorphism of the ACE gene and arterial distensibility in patients with type 2 diabetes and healthy control subjects.

RESEARCH DESIGN AND METHODS

Aortic and carotid arterial distensibility were evaluated by measuring aortic pulse-wave velocity (a-PWV) and carotid stiffness beta using an echo-tracking system in 137 patients with type 2 diabetes and 260 age-matched control subjects.

RESULTS

a-PWV and carotid stiffness beta were significantly higher in patients with type 2 diabetes than in age-matched control subjects (P < 0.05). Both stiffness beta and a-PWV were significantly higher in the patients with the II genotype than in those with the DD genotype (P < 0.001). In the control subjects, multiple regression analysis showed that age and decreased HDL cholesterol were independently associated with increased a-PWV (R2 = 0.244, P < 0.0001) and that age, systolic and diastolic blood pressure, and BMI were independently associated with increased carotid stiffness beta (R2 = 0.454, P < 0.0001). In the patients with type 2 diabetes, age, gene dose of the I allele, and systolic and diastolic blood pressure were independently associated with increased a-PWV (R2 = 0.545, P < 0.0001), and age, gene dose of the I allele, and systolic blood pressure were associated with increases in carotid stiffness beta (R2 = 0.314, P < 0.0001).

CONCLUSIONS

These results suggested that ACE polymorphism is associated with the impairment of aortic and carotid distensibility in patients with type 2 diabetes.

Correlation between the intima-media thickness of the carotid artery and aortic pulse-wave velocity in patients with type 2 diabetes. Vessel wall properties in type 2 diabetes

OBJECTIVE

The aim of this study was to assess the relationship between atherotic (structural) and sclerotic (functional) changes in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Aortic distensibility and carotid intimal-media thickness (IMT) were evaluated using carotid-femoral aortic pulse-wave velocity (a-PWV) and high-resolution B-mode ultrasonography in 271 patients with type 2 diabetes and 285 age-matched control subjects.

RESULTS

a-PWV and carotid IMT were significantly higher in the patients than in the control subjects in all age-groups (P < 0.0001, respectively). The carotid IMT and a-PWV were significantly correlated with age in both the patients with type 2 diabetes and control subjects. There was a significant positive relationship between the carotid IMT and a-PWV in both the patients (r = 0.482, P < 0.0001) and control subjects (r = 0.424, P < 0.0001). The slope of the regression line for the carotid IMT to the a-PWV was significantly steeper in the diabetic patients than in the control subjects (P < 0.05). Multiple regression analysis in all subjects showed that age, diabetic state, and cigarette smoking were independently common risk factors for the increase in carotid IMT and a-PWV. In the diabetic patients, the independent risk factors associated with the carotid IMT were age, hyperlipidemia, and duration of diabetes (R2 = 0.232, P < 0.0001), while those associated with a-PWV were age and duration of diabetes (R2 = 0.334, P < 0.0001).

CONCLUSIONS

The results indicated that diabetic patients showed more advanced changes in atherosis than that in sclerosis as compared with age- and sex-matched control subjects. Such atherotic changes in diabetic patients may be associated with hyperlipidemia.

Impaired endothelium-dependent vascular responses of retinal and intrarenal arteries in patients with type 2 diabetes

Endothelial dysfunction has been implicated in the pathogenesis of diabetic microangiopathies such as retinopathy and nephropathy as well as macrovascular diseases. The aim of the current study was to determine whether endothelial function in the retinal and renal arteries is impaired in type 2 diabetes mellitus. We examined the effects of an intravenous infusion of L-arginine and a sublingual administration of nitroglycerin on the brachial, retinal, and interlobar arterial hemodynamics in 20 type 2 diabetic patients (10 with normoalbuminuria and 10 with microalbuminuria) and 10 aged-matched control subjects. Despite no difference in the nitroglycerin-induced vascular response of the brachial or retinal artery among the 3 groups, the L-arginine-induced vascular response of each artery was significantly lower in both the normoalbuminuric and microalbuminuric patients than in the control subjects and the microalbuminuric patients showed the lowest value among the 3 groups (P<0.01, each artery, respectively). The L-arginine-induced vascular response of each artery was significantly correlated with HbA1c levels (brachial artery, r=0.617, P=0.0003; retinal artery, r=0.599, P=0.0005; interlobar artery, r=0.636, P=0.0002). In addition, stepwise multiple regression analysis of all subjects showed that HbA1c level was an independent determinant for the L-arginine-induced vascular response of each artery. The results showed that the endothelium-dependent vascular responses of the retinal and intrarenal arteries as well as the brachial artery were impaired in diabetic patients before the clinical manifestation of diabetic nephropathy, and suggest that endothelial dysfunction in these arteries is associated with hyperglycemia in these patients.

Homeostasis model assessment as a clinical index of insulin resistance in type 2 diabetic patients treated with sulfonylureas

OBJECTIVE

To investigate whether the insulin resistance index (IR) assessed by homeostasis model assessment (HOMA) is associated with the insulin resistance index assessed by euglycemic-hyperinsulinemic clamp (clamp IR) in type 2 diabetic patients who received sulfonylureas (SUs), as well as in those treated by diet alone.

RESEARCH DESIGN AND METHODS

Retrospectively, the association between HOMA IR and clamp IR was analyzed in 80 type 2 diabetic subjects (53 subjects treated with SUs and 27 subjects treated with diet alone). The 80 subjects, selected because they had not received insulin therapy, were among 111 diabetic participants in a clamp study for evaluation of insulin resistance from May 1993 to December 1997 in Osaka City University Hospital.

RESULTS

The HOMA IR showed a hyperbolic relationship with clamp IR. The log-transformed HOMA IR (all subjects, r = -0.725, P < 0.0001; SU group, r = -0.727, P < 0.0001; diet group, r = -0.747, P < 0.0001) correlated more strongly with clamp IR than did HOMA IR per se (all subjects, r = -0.594, P < 0.0001; SU group, r = -0.640, P < 0.0001; diet group, r = -0.632, P = 0.0004). The univariate regression line between log-transformed HOMA IR and clamp IR in the SU group did not differ from that in the diet group (slope, -6.866 vs. -5.120, P > 0.05; intercept, 6.566 vs. 5.478, P > 0.05). Stepwise multiple regression analyses demonstrated that the log-transformed HOMA IR was the strongest independent contributor to clamp IR (R2 = 0.640, P < 0.0001).

CONCLUSIONS

The HOMA IR strongly correlated with the clamp IR in type 2 diabetic patients treated with SUs as well as in those treated with diet alone.

Serum levels of 1,25-dihydroxyvitamin D, 24,25-dihydroxyvitamin D, and 25-hydroxyvitamin D in nondialyzed patients with chronic renal failure

BACKGROUND

In patients with chronic renal failure (CRF), abnormalities in vitamin D metabolism are known to be present, and several factors could contribute to the abnormalities.

METHODS

We measured serum levels of three vitamin D metabolites, 1,25(OH)2D, 24, 25(OH)2D and 25(OH)D, and analyzed factors affecting their levels in 76 nondialyzed patients with CRF (serum creatinine> 1.6 and < 9.0 mg/dl), 37 of whom had diabetes mellitus (DM-CRF) and 39 of whom were nondiabetic (nonDM-CRF).

RESULTS

Serum levels of 1,25(OH)2D were positively correlated with estimated creatinine clearance (CCr; r = 0.429; P < 0.0001), and levels of 24,25(OH)2D were weakly correlated with CCr (r = 0.252, P < 0.05); no correlation was noted for 25(OH)D. Serum levels of all three vitamin D metabolites were significantly and positively correlated with serum albumin. Although there were no significant differences in age, sex, estimated CCr, calcium and phosphate between DM-CRF and nonDM-CRF, all three vitamin D metabolites were significantly lower in DM-CRF than in nonDM-CRF. To analyze factors influencing vitamin D metabolite levels, we performed multiple regression analyses. Serum 25(OH)D levels were significantly and independently associated with serum albumin, presence of DM and serum phosphate (R2 = 0.599; P < 0.0001). 24,25(OH)2D levels were significantly and strongly associated with 25(OH)D (beta = 0.772; R2 = 0.446; P < 0.0001). Serum 1,25(OH)2D levels were significantly associated only with estimated CCr (R2 = 0. 409; P < 0.0001).

CONCLUSIONS

These results suggest that hypoalbuminemia and the presence of DM independently affect serum 25(OH)D levels, probably via diabetic nephropathy and poor nutritional status associated with diabetes, and that 25(OH)D is actively catalyzed to 24,25(OH)2D in CRF, probably largely via extrarenal 24-hydroxylase. Serum levels of 1,25(OH)2D were significantly affected by the degree of renal failure. Thus, this study indicates that patients with CRF, particularly those with DM, should receive supplements containing the active form of vitamin D prior to dialysis.

Poor glycemic control impairs the response of biochemical parameters of bone formation and resorption to exogenous 1,25-dihydroxyvitamin D3 in patients with type 2 diabetes

Osteoblast deficit plays a principal role in the development of diabetic osteopenia. We have previously reported that high glucose conditions impair the function of osteoblast-like MG-63 cells. This study was performed to assess the sensitivity of osteoblasts to 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in patients with type 2 diabetes without insulin deficiency or overt diabetic complications. During stimulation with 1,25(OH)2D3 at 2.0 micrograms/day for 6 consecutive days in 9 type 2 diabetic patients, serum levels of bone alkaline phosphatase (BALP), osteocalcin (OC) and the carboxyterminal propeptide of type 1 procollagen, and the urinary excretion of pyridinoline and deoxypyridinoline (DPYR), were monitored. As parameters of glycemic control, the mean level of fasting plasma glucose (mFPG) throughout the 1,25(OH)2D3 stimulation test and the level of HbA1C were used. 1,25(OH)2D3 increased serum 1,25(OH)2D significantly by day 2, which was followed by a significant reduction in the serum level of intact parathyroid hormone. The maximal increment of serum OC adjusted for that of 1,25(OH)2D was negatively correlated with both mFPG and HbA1C levels (p < 0.05). Furthermore, the magnitude of 1,25(OH)2D3-induced bone resorption, as reflected by the maximal increase in urinary DPYR excretion, was negatively correlated with the mFPG level (p < 0.05). Basal BALP tended to be negatively correlated with HbA1C, although not to a significant extent. In conclusion, our findings would indicate that poor glycemic control impairs the responses of osteoblasts and osteoclasts to 1,25(OH)2D3 in normo-insulinemic type 2 diabetic patients.