bluuebunny/crossref_metadata_2025 huggingface dataset:
Central Obesity and the Metabolic Syndrome: Implications for Primary Care Providers
Authors: Appel Susan J. , Jones Ellen D. , Kennedy‐Malone Laurie
Published: May 2005

Purpose

To describe screening measures that will determine which clients are at risk for the metabolic syndrome, common manifestations of the syndrome, preventive diagnostic considerations, and management and treatment options that primary care providers can implement.

Data Sources

Review of the clinical and research literature, supple mented with specific diagnostic criteria.

Conclusions

Central obesity is the cornerstone of the metabolic syndrome, which may lead to type 2 diabetes and cardiovascular disease. Generalized obesity is defined body weight that is considerably greater than the ideal weight and that is distributed on all parts of the body. Generalized obesity has long been considered a significant risk factor for developing type 2 diabetes and cardiovascular disease.Those clients of ideal body weight have been considered at less risk for developing these conditions. However, this perception may not always be accurate. Weight distribution plays a major role in acquiring the metabolic syndrome.Because waist circumference is important as overall body weight, central obesity is key determining the risk.

Implications for Practice

The metabolic syndrome has now been given a CPT code (277.7). It is more likely that clients at risk for or with the metabolic syndrome may first be seen by a primary care provider. Primary care providers need to be able to diagnose treat and provide preventive interventions for the metabolic syndrome. Clients at risk will likely be identified during routine health screening. Early detection of and interventions focused on the metabolic syndrome may reduce the occurrence of type 2 diabetes and cardiovascular disease. Use of a tape measure to determine waist circumference may help the provider to identify at‐risk clients who are of normal weight and thus not previously believed to be at risk, as well as those more obviously at risk. It is necessary to determine not only patients' overall body weight but also their waist circumference. A measuring tape may be the key tool for establishing a patient's early risk for the metabolic syndrome and ultimately for prevention of type 2 diabetes and cardiovascular disease.
Heat Transfer, Pressure Loss and Flow Field Measurements Downstream of Staggered Two-Row Circular and Elliptical Pin Fin Arrays
Authors: Uzol Oguz , Camci Cengiz
Published: May 2005

This paper presents the results of heat transfer, total pressure loss, and wake flow field measurements downstream of two-row staggered elliptical and circular pin fin arrays. Two different types of elliptical fins are tested, i.e., a Standard Elliptical Fin (SEF) and a fin that is based on NACA four digit symmetrical airfoil shapes (N fin). The results are compared to those of a corresponding circular pin fin array. The minor axis lengths for both types of elliptical fins are kept equal to the diameter of the circular fins. Experiments are performed using Liquid Crystal Thermography and total pressure probe wake surveys in a Reynolds number range of 18 000 and 86 000 as well as Particle Image Velocimetry (PIV) measurements at ReD=18 000. The pin fins had a height-to-diameter ratio of 1.5. The streamwise and the transverse spacings were equal to one circular fin diameter, i.e., S/D=X/D=2. For the circular fin array, average Nusselt numbers on the endwall within the wake are about 27% higher than those of SEF and N fin arrays. Different local heat transfer enhancement patterns are observed for elliptical and circular fins. In terms of total pressure loss, there is a substantial reduction in case of SEF and N fins. The loss levels for the circular fin are 46.5% and 59.5% higher on average than those of the SEF and N fins, respectively. An examination of the Reynolds analogy performance parameter show that the performance indices of the SEF and the N fins are 1.49 and 2.0 times higher on average than that of circular fins, respectively. The thermal performance indices show a collapse of the data, and the differences are much less evident. Nevertheless, N fins still show slightly higher thermal performance values. The wake flow field measurements show that the circular fin array creates a relatively large low momentum wake zone compared to the SEF and N fin arrays. The wake trajectories of the first row of fins in circular, SEF and N fin arrays are also different from each other. The turbulent kinetic energy levels within the wake of the circular fin array are higher than those for the SEF and the N fin arrays. The transverse variations in turbulence levels correlate well with the corresponding local heat transfer enhancement variations.
A Critical Assessment of Reynolds Analogy for Turbine Flows
Authors: Bons J.
Published: May 2005

The application of Reynolds analogy 2St/cf≅1 for turbine flows is critically evaluated using experimental data collected in a low-speed wind tunnel. Independent measurements of St and cf over a wide variety of test conditions permit assessments of the variation of the Reynolds analogy factor (i.e., 2St/cf) with Reynolds number, freestream pressure gradient, surface roughness, and freestream turbulence. While the factor is fairly independent of Reynolds number, it increases with positive (adverse) pressure gradient and decreases with negative (favorable) pressure gradient. This variation can be traced directly to the governing equations for momentum and energy which dictate a more direct influence of pressure gradient on wall shear than on energy (heat) transfer. Surface roughness introduces a large pressure drag component to the net skin friction measurement without a corresponding mechanism for a comparable increase in heat transfer. Accordingly, the Reynolds analogy factor decreases dramatically with surface roughness (by as much as 50% as roughness elements become more prominent). Freestream turbulence has the opposite effect of increasing heat transfer more than skin friction, thus the Reynolds analogy factor increases with turbulence level (by up to 35% at a level of 11% freestream turbulence). Physical mechanisms responsible for the observed variations are offered in each case. Finally, synergies resulting from the combinations of pressure gradient and freestream turbulence with surface roughness are evaluated. With this added insight, the Reynolds analogy remains a useful tool for qualitative assessments of complex turbine flows where both heat load management and aerodynamic efficiency are critical design parameters.
Experimental Investigation of Flow Structure and Nusselt Number in a Low-Speed Linear Blade Passage With and Without Leading-Edge Fillets
Authors: Mahmood G. I. , Gustafson R. , Acharya S.
Published: May 2005

The potential of contouring the leading edge of a blade to control the development of the secondary flows in the blade passage and to reduce the thermal loading to the end wall is investigated experimentally. Fillets placed at the junctions of the leading edge and the end wall are used for contouring. Four different types of fillet profiles are tested in a low-speed linear cascade a Reynolds numbers of 233,000 based on the inlet velocity. Images of instantaneous smoke flow patterns show a smaller horseshoe vortex along the leading edge with the fillets. In the passage, the fillets cause the passage vortex to be located closer to the suction surface. Upstream of the throat, the normalized axial vorticity values for the passage vortex and the turbulence intensity levels are smaller with the fillets compared to the baseline. For the leading-edge fillet with a concave profile, the end-wall Nusselt number distributions show significant reductions compared to the baseline.
Development of Taylor-Go¨rtler Vortices Over the Pressure Surface of a Turbine Blade
Authors: Wang H. P. , Olson S. J. , Goldstein R. J.
Published: May 2005

The naphthalene sublimation technique is used to investigate the development of Taylor-Go¨rtler vortices over the pressure surface of a simulated high performance turbine blade. Large spanwise variation in mass transfer is observed downstream on the pressure surface in the two-dimensional flow region for cases with low freestream turbulence, indicating the existence of Taylor-Go¨rtler vortices. Different average and local mass transfer rates for the same flow conditions suggest that roughness variation near the leading edge affects the initial formation of Taylor-Go¨rtler vortices. Larger and more uniformly distributed roughness at the leading edge produces much stronger Taylor-Go¨rtler vortices downstream and greatly enhances the mass transfer rate. The variation between the vortices does not change appreciably along the flow direction. The flow in the boundary layer is laminar over the entire pressure surface. In the presence of external disturbances such as high freestream turbulence or a boundary layer trip, no Taylor-Go¨rtler vortices are observed.
Phosphorylation of Ribavirin and Viramidine by Adenosine Kinase and Cytosolic 5′-Nucleotidase II: Implications for Ribavirin Metabolism in Erythrocytes
Authors: Wu Jim Zhen , Larson Gary , Walker Heli , Shim Jae Hoon , Hong Zhi
Published: May 2005

Many nucleoside analog drugs, such as ribavirin and viramidine, are activated or metabolized in vivo through 5′-phosphorylation. In this report, we determined the steady-state kinetic parameters for 5′-monophosphorylation of ribavirin and viramidine by adenosine kinase. The apparentKmfor ribavirin is 540 μM, andkcatis 1.8 min−1. Its catalytic efficiency of 3.3 × 10−3min−1· μM−1is 1,200-fold lower than that of adenosine. In contrast to the common belief that ribavirin is exclusively phosphorylated by adenosine kinase, cytosolic 5′-nucleotidase II was found to catalyze ribavirin phosphorylation in vitro. The reaction is optimally stimulated by the physiological concentration of ATP or 2,3-bisphosphoglycerate. In phosphate-buffered saline plus ATP and 2,3-bisphosphoglycerate, the apparentKmfor ribavirin is 88 μM, andkcatis 4.0 min−1. These findings suggest that cytosolic 5′-nucleotidase II may be involved in ribavirin phosphorylation in vivo. Like ribavirin, viramidine was found to be phosphorylated by either adenosine kinase or cytosolic 5′-nucleotidase II, albeit with a much lower activity. The catalytic efficiency for viramidine phosphorylation is 10- to 330-fold lower than that of ribavirin, suggesting that other nucleoside kinase(s) may be involved in viramidine phosphorylation in vivo. Both ribavirin and viramidine are not phosphorylated by deoxycytidine kinase and uridine-cytidine kinase. The coincidence of presence of high concentrated 2,3-bisphosphoglycerate in erythrocytes suggests that cytosolic 5′-nucleotidase II could play an important role in phosphorylating ribavirin and contribute to anabolism of ribavirin triphosphate in erythrocytes. Elucidation of ribavirin and viramidine phosphorylation mechanism should shed light on their in vivo metabolism, especially the ribavirin-induced hemolytic anemia in erythrocytes.
Are Transporter Genes Other than the Chloroquine Resistance Locus (
pfcrt
) and Multidrug Resistance Gene (
pfmdr
) Associated with Antimalarial Drug Resistance?
Authors: Anderson Timothy J. C. , Nair Shalini , Qin Huang , Singlam Sittaporn , Brockman Alan , Paiphun Lucy , Nosten François
Published: May 2005

Mu et al. (Mu, J., M. T. Ferdig, X. Feng, D. A. Joy, J. Duan, T. Furuya, G. Subramanian, L. Aravind, R. A. Cooper, J. C. Wootton, M. Xiong, and X. Z. Su, Mol. Microbiol.
49:
977-989, 2003) recently reported exciting associations between nine new candidate transporter genes and in vitro resistance to chloroquine (CQ) and quinine (QN), with six of these loci showing association with CQ or QN in a southeast Asian population sample. We replicated and extended this work by examining polymorphisms in these genes and in vitro resistance to eight drugs in parasites collected from the Thailand-Burma border. To minimize problems of multiple testing, we used a two-phase study design, while to minimize problems caused by population structure, we analyzed parasite isolates collected from a single clinic. We first examined associations between genotype and drug response in 108 unique single-clone parasite isolates. We found strong associations between single nucleotide polymorphisms in
pfmdr
and mefloquine (MFQ), artesunate (AS), and lumefantrine (LUM) response. We also observed associations between an ABC transporter (G7) and response to QN and AS and between another ABC transporter (G49) and response to dihydro-artemisinin (DHA). We reexamined significant associations in an independent sample of 199 unique single-clone infections from the same location. The significant associations with
pfmdr-
1042 detected in the first survey remained. However, with the exception of the G7-artesunate association, all other associations observed with the nine new candidate transporters disappeared. We also examined linkage disequilibrium (LD) between markers and phenotypic correlations between drug responses. We found minimal LD between genes. Furthermore, we found no correlation between chloroquine and quinine responses, although we did find expected strong correlations between MFQ, QN, AS, DHA, and LUM. To conclude, we found no evidence for an association between 8/9 candidate genes and response to eight different antimalarial drugs. However, the consistent association observed between a 3-bp indel in G7 and AS response merits further investigation.
Phenotypic and Molecular Characterization of
Mycobacterium tuberculosis
Isolates Resistant to both Isoniazid and Ethambutol
Authors: Parsons Linda M. , Salfinger Max , Clobridge Anne , Dormandy Jillian , Mirabello Lisa , Polletta Valerie L. , Sanic Ahmet , Sinyavskiy Oleg , Larsen Susan C. , Driscoll Jeffrey , Zickas Genet , Taber Harry W.
Published: May 2005

In performing radiometric susceptibility testing on over 2,000 patient isolates of
Mycobacterium tuberculosis
during the past 6 years, we found that resistance to 7.5 μg/ml ethambutol (EMB) occurred only in isolates that are also resistant to 0.4 μg/ml isoniazid (INH). Using 157 selected isolates in the present study, we performed radiometric and agar proportion susceptibility tests and DNA sequencing of genetic regions associated with resistance to these two drugs. The goal was to study the occurrence of the common mutations associated with resistance to each drug and also to determine whether any particular INH-resistance-associated mutation occurred more often in combination with any particular EMB-resistance-associated mutation. In an analysis of 128 isolates resistant to 0.4 μg/ml INH, we found that a mutation at
katG
Ser315 was more common in isolates also resistant to 7.5 μg/ml EMB (61 of 67 = 91.0%) than in isolates either susceptible to EMB or resistant to 2.5 μg/ml EMB (39 of 60 = 65.0%). These observations suggest that INH-resistant strains with a mutation at
katG
Ser315 are more likely to acquire resistance to 7.5 μg/ml EMB than are isolates with INH-resistance-associated mutations at other sites. In addition, we found that 64 of 67 (95.5%) isolates resistant to 7.5 μg/ml EMB contained a mutation in either codon 306 or codon 406 of
embB.
Met306Val was the most common
embB
mutation, present in 52 (77.6%) of the 67 isolates. Most occurrences of this mutation (49 of 52 = 94.2%) were found in isolates that also contained the
katG
Ser315Thr mutation. Finally, sequencing this region of
embB
appears to be sufficiently sensitive for use as a rapid screening tool for detection of high-level resistance to EMB.
Genome-Wide Expression Profiling of the Response to Azole, Polyene, Echinocandin, and Pyrimidine Antifungal Agents inCandida albicans
Authors: Liu Teresa T. , Lee Robin E. B. , Barker Katherine S. , Lee Richard E. , Wei Lai , Homayouni Ramin , Rogers P. David
Published: May 2005

Antifungal agents exert their activity through a variety of mechanisms, some of which are poorly understood. We examined changes in the gene expression profile ofCandida albicansfollowing exposure to representatives of the four currently available classes of antifungal agents used in the treatment of systemic fungal infections. Ketoconazole exposure increased expression of genes involved in lipid, fatty acid, and sterol metabolism, includingNCP1,MCR1,CYB5,ERG2,ERG3,ERG10,ERG25,ERG251, and that encoding the azole target,ERG11. Ketoconazole also increased expression of several genes associated with azole resistance, includingCDR1,CDR2,IFD4,DDR48, andRTA3. Amphotericin B produced changes in the expression of genes involved in small-molecule transport (ENA21), and in cell stress (YHB1,CTA1,AOX1, andSOD2). Also observed was decreased expression of genes involved in ergosterol biosynthesis, includingERG3andERG11. Caspofungin produced changes in expression of genes encoding cell wall maintenance proteins, including the β-1,3-glucan synthase subunitGSL22, as well asPHR1,ECM21,ECM33, andFEN12. Flucytosine increased the expression of proteins involved in purine and pyrimidine biosynthesis, includingYNK1,FUR1, and that encoding its target,CDC21. Real-time reverse transcription-PCR was used to confirm microarray results. Genes responding similarly to two or more drugs were also identified. These data shed new light on the effects of these classes of antifungal agents onC. albicans.
New Mutations and Horizontal Transfer of
rpoB
among Rifampin-Resistant
Streptococcus pneumoniae
from Four Spanish Hospitals
Authors: Ferrándiz María José , Ardanuy Carmen , Liñares Josefina , García-Arenzana José María , Cercenado Emilia , Fleites Ana , de la Campa Adela G.
Published: May 2005

A total of 103 (0.7%) of 14,236
Streptococcus pneumoniae
isolates collected in four Spanish hospitals from 1989 to 2003 were resistant to rifampin (MICs, 4 to 512 μg/ml). Only sixty-one (59.2%) of these isolates were available for molecular characterization. Resistance was mostly related to human immunodeficiency virus (HIV) infection in adult patients and to conjunctivitis in children. Thirty-six different pulsed-field gel electrophoresis patterns were identified among resistant isolates, five of which were related to international clones (Spain
23F
-1, Spain
6B
-2, Spain
9V
-3, Spain
14
-5, and clone C of serotype 19F), and accounted for 49.2% of resistant isolates. Single sense mutations at cluster N or I of the
rpoB
gene were found in 39 isolates, while double mutations, either at cluster I, at clusters I and II, or at clusters N and III, were found in 14 isolates. The involvement of the mutations in rifampin resistance was confirmed by genetic transformation. Single mutations at clusters N and I conferred MICs of 2 μg/ml and 4 to 32 μg/ml, respectively. Eight isolates showed high degrees of nucleotide sequence variations (2.3 to 10.8%) in
rpoB
, suggesting a recombinational origin for these isolates, for which viridans group streptococci are their potential gene donors. Although the majority of rifampin-resistant isolates were isolated from individual patients without temporal or geographical relationships, the clonal dissemination of rifampin-resistant isolates was observed among 12 HIV-infected patients in the two hospitals with higher rates of resistance.
Transcriptional Response of
Enterococcus faecalis
V583 to Erythromycin
Authors: Aakra Ågot , Vebø Heidi , Snipen Lars , Hirt Helmut , Aastveit Are , Kapur Vivek , Dunny Gary , Murray Barbara , Nes Ingolf F.
Published: May 2005

A transcriptional profile of
Enterococcus faecalis
V583 (V583) treated with erythromycin is presented. This is the first study describing a complete transcriptional profile of
Enterococcus. E. faecalis
is a common and nonvirulent bacterium in many natural environments, but also an important cause of nosocomial infections. We have used a genome-wide microarray based on the genome sequence of V583 to study gene expression in cells exposed to erythromycin. V583 is resistant to relatively high concentrations of erythromycin, but growth is retarded by the treatment. The effect of erythromycin treatment on V583 was studied by a time course experiment; samples were extracted at five time points over a period of 90 min. A drastic change in gene transcription was seen with the erythromycin-treated cells compared to the untreated cells. Altogether, 260 genes were down-regulated at one or more time points, while 340 genes were up-regulated. Genes encoding hypothetical proteins and genes encoding transport and binding proteins were the two most dominating groups of differentially expressed genes. The gene encoding
ermB
(EFA0007) was expressed, but not differentially, which indicated that other genes are important for the survival and growth maintenance of V583 treated with erythromycin. One of these genes is a putative MsrC-like protein, which was up-regulated at all time points studied. Other specific genes that were found to be up-regulated were genes encoding ABC transporters and two-component regulatory systems, and these may be genes that are important for the specific response of V583 to erythromycin.
Linezolid versus Vancomycin in Treatment of Complicated Skin and Soft Tissue Infections
Authors: Weigelt John , Itani Kamal , Stevens Dennis , Lau William , Dryden Matthew , Knirsch Charles
Published: May 2005

Skin and soft tissue infections (SSTIs) are a common cause of morbidity in both the community and the hospital. An SSTI is classified as complicated if the infection has spread to the deeper soft tissues, if surgical intervention is necessary, or if the patient has a comorbid condition hindering treatment response (e.g., diabetes mellitus or human immunodeficiency virus). The purpose of this study was to compare linezolid to vancomycin in the treatment of suspected or proven methicillin-resistant gram-positive complicated SSTIs (CSSTIs) requiring hospitalization. This was a randomized, open-label, comparator-controlled, multicenter, multinational study that included patients with suspected or proven methicillin-resistant
Staphylococcus aureus
(MRSA) infections that involved substantial areas of skin or deeper soft tissues, such as cellulitis, abscesses, infected ulcers, or burns (<10% of total body surface area). Patients were randomized (1:1) to receive linezolid (600 mg) every 12 h either intravenously (i.v.) or orally or vancomycin (1 g) every 12 h i.v. In the intent-to-treat population, 92.2% and 88.5% of patients treated with linezolid and vancomycin, respectively, were clinically cured at the test-of-cure (TOC) visit (
P
= 0.057). Linezolid outcomes (124/140 patients or 88.6%) were superior to vancomycin outcomes (97/145 patients or 66.9%) at the TOC visit for patients with MRSA infections (
P
< 0.001). Drug-related adverse events were reported in similar numbers in both the linezolid and the vancomycin arms of the trial. The results of this study demonstrate that linezolid therapy is well tolerated, equivalent to vancomycin in treating CSSTIs, and superior to vancomycin in the treatment of CSSTIs due to MRSA.
Inducible Clindamycin Resistance and Molecular Epidemiologic Trends of Pediatric Community-Acquired Methicillin-Resistant
Staphylococcus aureus
in Dallas, Texas
Authors: Chavez-Bueno Susana , Bozdogan Bülent , Katz Kathy , Bowlware Karen L. , Cushion Nancy , Cavuoti Dominick , Ahmad Naveed , McCracken George H. , Appelbaum Peter C.
Published: May 2005

Community-acquired methicillin-resistant
Staphylococcus aureus
(CA-MRSA) infection occurs commonly in children. Clindamycin resistance may be inducible or constitutive, and the rates of inducible resistance in CA-MRSA that could produce clindamycin treatment failures vary worldwide. The double-disk test was performed in 197 erythromycin-resistant and clindamycin-susceptible CA-MRSA strains from children in Dallas, Texas, from 1999 to 2002 to determine inducible clindamycin resistance. Resistance mechanisms were studied by PCR; epidemiologic trends were studied by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Inducible resistance was demonstrated in 28 (93% ±6%) of 30 tested isolates in 1999, 21 (64%, ±11%) of 33 in 2000, 12 (23% ±7%) of 52 in 2001, and 6 (7% ±3%) of 82 in 2002. All noninducible strains had the
msr
(A) gene. Among inducible resistant strains, 31 had
erm
(B), 24 had
erm
(C), and 12 had
erm
(A) genes. Two distinct pulsed types were the most prevalent; one of them was the most common pulsed type in 1999, whereas in 2002 a different pulsed type was prevalent. MLST analyses determined that ST-8 was the most common type, with 76% ±5% found in 2002. All but one of these clindamycin-susceptible, erythromycin-resistant ST-8 strains showed no induction of clindamycin resistance. We conclude that, among erythromycin-resistant, clindamycin-susceptible CA-MRSA strains isolated from children in Dallas, inducible methylase resistance became less common from 1999 to 2002 (
P
< 0.001). The phenotype of strains was associated with their sequence type. Our results demonstrate a clonal shift in CA-MRSA in Dallas children from 1999 to 2002.
Bactericidal Activity of the Nitroimidazopyran PA-824 in a Murine Model of Tuberculosis
Authors: Tyagi Sandeep , Nuermberger E. , Yoshimatsu T. , Williams K. , Rosenthal I. , Lounis N. , Bishai W. , Grosset J.
Published: May 2005

The nitroimidazopyran PA-824 has potent in vitro activity against
Mycobacterium tuberculosis
, a narrow spectrum of activity limited primarily to the
M. tuberculosis
complex, and no demonstrable cross-resistance to a variety of antituberculosis drugs. In a series of experiments, we sequentially characterized the activity of PA-824 in an experimental murine model of tuberculosis. The minimal effective dose was 12.5 mg/kg of body weight/day. The minimal bactericidal dose (MBD) was 100 mg/kg/day. When PA-824 was used as monotherapy at the MBD, it exhibited promising bactericidal activity during the initial intensive phase of therapy that was similar to that of the equipotent dose of isoniazid in humans. In combination with isoniazid, PA-824 prevented the selection of isoniazid-resistant mutants. Perhaps more importantly, PA-824 also demonstrated potent activity during the continuation phase of therapy, during which it targeted bacilli that had persisted through an initial 2-month intensive phase of treatment with rifampin, isoniazid, and pyrazinamide. Together, these data strongly support further evaluation of PA-824 in combination with first- or second-line antituberculosis drugs to determine its potential contribution to the treatment of drug-susceptible or multidrug-resistant tuberculosis, respectively.
TMC114, a Novel Human Immunodeficiency Virus Type 1 Protease Inhibitor Active against Protease Inhibitor-Resistant Viruses, Including a Broad Range of Clinical Isolates
Authors: De Meyer Sandra , Azijn Hilde , Surleraux Dominique , Jochmans Dirk , Tahri Abdellah , Pauwels Rudi , Wigerinck Piet , de Béthune Marie-Pierre
Published: May 2005

The purpose of this study was to characterize the antiviral activity, cytotoxicity, and mechanism of action of TMC114, a novel human immunodeficiency virus type 1 (HIV-1) protease inhibitor (PI). TMC114 exhibited potent anti-HIV activity with a 50% effective concentration (EC
50
) of 1 to 5 nM and a 90% effective concentration of 2.7 to 13 nM. TMC114 exhibited no cytotoxicity at concentrations up to 100 μM (selectivity index, >20,000). All viruses in a panel of 19 recombinant clinical isolates carrying multiple protease mutations and demonstrating resistance to an average of five other PIs, were susceptible to TMC114, defined as a fold change in EC
50
of <4. TMC114 was also effective against the majority of 1,501 PI-resistant recombinant viruses derived from recent clinical samples, with EC
50
s of <10 nM for 75% of the samples. In sequential passage experiments using HIV-1 LAI, two mutations (R41T and K70E) were selected. One selected virus showed a 10-fold reduction in susceptibility to TMC114, but <10-fold reductions in susceptibility to the current PIs (atazanavir was not assessed), except saquinavir. However, when the selected mutations were introduced into a laboratory strain by site-directed mutagenesis, they had no effect on susceptibility to TMC114 or other PIs. There was no evidence of antagonism between TMC114 and any currently available PIs or reverse transcriptase inhibitors. Combinations with ritonavir, nelfinavir, and amprenavir showed some evidence of synergy. These results suggest that TMC114 is a potential candidate for the treatment of both naïve and PI-experienced patients with HIV.
Divalent Metal Cations Increase the Activity of the Antimicrobial Peptide Kappacin
Authors: Dashper Stuart G. , O'Brien-Simpson Neil M. , Cross Keith J. , Paolini Rita A. , Hoffmann Brigitte , Catmull Deanne V. , Malkoski Marina , Reynolds Eric C.
Published: May 2005

Kappacin, nonglycosylated κ-casein(106-169), is a novel antimicrobial peptide produced from κ-casein found in bovine milk. There are two major genetic forms of kappacin, A and B, and using synthetic peptides corresponding to the active region, κ-casein(138-158), of these forms, we have shown that the Asp
148
to Ala
148
substitution is responsible for the lesser antibacterial activity of κ-casein-B(106-169). Kappacin was shown to have membranolytic action at concentrations above 30 μM at acidic pH when tested against artificial liposomes. There was little membranolytic activity at neutral pH, which is consistent with the lack of antibacterial activity of kappacin against
Streptococcus mutans
at this pH. Kappacin specifically bound two zinc or calcium ions per mol, and this binding enhanced antibacterial activity at neutral pH. Nuclear magnetic resonance analysis indicated that a κ-casein-A(138-158) synthetic peptide undergoes a conformational change in the presence of the membrane solvent trifluoroethanol and excess divalent metal ions. This change in conformation is presumably responsible for the increase in antibacterial activity of kappacin detected in the presence of excess zinc or calcium ions at neutral pH. When tested against the oral bacterial pathogen
S. mutans
cultured as a biofilm in a constant-depth film fermentor, a preparation of 10 g/liter kappacin and 20 mM ZnCl
2
reduced bacterial viability by 3 log
10
and suppressed recovery of viability. In contrast 20 mM ZnCl
2
alone reduced bacterial viability by ≈1 log
10
followed by rapid recovery. In conclusion, kappacin has a membranolytic, antibacterial effect that is enhanced by the presence of divalent cations.
Biological Cost of Single and Multiple Norfloxacin Resistance Mutations in
Escherichia coli
Implicated in Urinary Tract Infections
Authors: Lindgren Patricia Komp , Marcusson Linda L. , Sandvang Dorthe , Frimodt-Møller Niels , Hughes Diarmaid
Published: May 2005

Resistance to fluoroquinolones in urinary tract infection (UTIs) caused by
Escherichia coli
is associated with multiple mutations, typically those that alter DNA gyrase and DNA topoisomerase IV and those that regulate AcrAB-TolC-mediated efflux. We asked whether a fitness cost is associated with the accumulation of these multiple mutations. Mutants of the susceptible
E. coli
UTI isolate Nu14 were selected through three to five successive steps with norfloxacin. Each selection was performed with the MIC of the selected strain. After each selection the MIC was measured; and the regions of
gyrA
,
gyrB
,
parC
, and
parE
, previously associated with resistance mutations, and all of
marOR
and
acrR
were sequenced. The first selection step yielded mutations in
gyrA
,
gyrB
, and
marOR
. Subsequent selection steps yielded mutations in
gyrA
,
parE
, and
marOR
but not in
gyrB
,
parC
, or
acrR
. Resistance-associated mutations were identified in almost all isolates after selection steps 1 and 2 but in less than 50% of isolates after subsequent selection steps. Selected strains were competed in vitro, in urine, and in a mouse UTI infection model against the starting strain, Nu14. First-step mutations were not associated with significant fitness costs. However, the accumulation of three or more resistance-associated mutations was usually associated with a large reduction in biological fitness, both in vitro and in vivo. Interestingly, in some lineages a partial restoration of fitness was associated with the accumulation of additional mutations in late selection steps. We suggest that the relative biological costs of multiple mutations may influence the evolution of
E. coli
strains that develop resistance to fluoroquinolones.
Intravesical Nitric Oxide Delivery for Prevention of Catheter-Associated Urinary Tract Infections
Authors: Carlsson Stefan , Weitzberg Eddie , Wiklund Peter , Lundberg Jon O.
Published: May 2005

The use of indwelling urinary catheters is a major risk factor for urinary tract infection; and despite the availability of numerous preventive regimens, this condition is still extremely common. In earlier studies we have demonstrated the inhibitory effects of nitrite and ascorbic acid on bacterial growth in urine. When combined, these compounds generate antibacterial reactive nitrogen species, including the gas nitric oxide. We have now tested in a laboratory model of the urinary bladder whether filling of the catheter retention balloon with nitrite and ascorbic acid would generate measurable amounts of NO outside the membrane and whether this would affect bacterial growth in the surrounding urine. Two strains of
Escherichia coli
, one strain isolated from a patient (U1106024) and one reference strain (ATCC 25922), were tested. Nitric oxide gas was generated in the silicone balloon and readily diffused into the urine. When control catheters with ascorbic acid but without nitrite were used, bacterial counts increased from 9.0 × 10
5
to 2.0 ×10
8
CFU/ml (strain U1106024) and from 2.5 × 10
6
to 2.7 × 10
8
CFU/ml (strain ATCC 25922) after 24 h. In contrast, in test catheters with ascorbic acid and nitrite, both strains tested were effectively killed. The NO donor {DETA NONOate, (
Z
)-1-[
N
-(2-aminoethyl)-
N
-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate} also showed antibacterial activity in the same model, thereby supporting a central role of NO in achieving the observed effects. Future clinical trials will reveal whether this novel approach for the intravesical delivery of an antibacterial gas could be used to prevent catheter-associated infections.
Inhibitory Activity of Human Immunodeficiency Virus Aspartyl Protease Inhibitors against
Encephalitozoon intestinalis
Evaluated by Cell Culture-Quantitative PCR Assay
Authors: Menotti Jean , Santillana-Hayat Maud , Cassinat Bruno , Sarfati Claudine , Derouin Francis , Molina Jean-Michel
Published: May 2005

Immune reconstitution might not be the only factor contributing to the low prevalence of microsporidiosis in human immunodeficiency virus (HIV)-infected patients treated with protease inhibitors, as these drugs may exert a direct inhibitory effect against fungi and protozoa. In this study, we developed a cell culture-quantitative PCR assay to quantify
Encephalitozoon intestinalis
growth in U-373-MG human glioblastoma cells and used this assay to evaluate the activities of six HIV aspartyl protease inhibitors against
E. intestinalis
. A real-time quantitative PCR assay targeted the
E. intestinalis
small-subunit rRNA gene. HIV aspartyl protease inhibitors were tested over serial concentrations ranging from 0.2 to 10 mg/liter, with albendazole used as a control. Ritonavir, lopinavir, and saquinavir were able to inhibit
E. intestinalis
growth, with 50% inhibitory concentrations of 1.5, 2.2, and 4.6 mg/liter, respectively, whereas amprenavir, indinavir, and nelfinavir had no inhibitory effect. Pepstatin A, a reference aspartyl protease inhibitor, could also inhibit
E. intestinalis
growth, suggesting that HIV protease inhibitors may act through the inhibition of an
E. intestinalis
-encoded aspartyl protease. These results showed that some HIV protease inhibitors can inhibit
E. intestinalis
growth at concentrations that are achievable in vivo and that the real-time quantitative PCR assay that we used is a valuable tool for the in vitro assessment of the activities of drugs against
E. intestinalis
.
Interferon Alfacon-1 Protects Hamsters from Lethal Pichinde Virus Infection
Authors: Gowen Brian B. , Barnard Dale L. , Smee Donald F. , Wong Min-Hui , Pace Anne M. , Jung Kie-Hoon , Winslow Scott G. , Bailey Kevin W. , Blatt Lawrence M. , Sidwell Robert W.
Published: May 2005

Hemorrhagic fever of arenaviral origin is a frequently fatal infectious disease of considerable priority to the biodefense mission. Historically, the treatment of arenaviral infections with alpha interferons has not yielded favorable results. Here we present evidence that interferon alfacon-1, a nonnaturally occurring bioengineered alpha interferon approved for the treatment of chronic hepatitis C, is active against Pichinde and Tacaribe arenaviruses in cell culture. In the hamster model of Pichinde virus (PCV) infection, interferon alfacon-1 treatment significantly protected animals from death, prolonged the survival of those that eventually died, reduced virus titers, and limited liver damage characteristic of PCV-induced disease. Moreover, interferon alfacon-1 also demonstrated therapeutic activity, to a lesser degree, when the initiation of treatment was delayed up to 2 days post-virus challenge. Despite the observed advantages of interferon alfacon-1 therapy, efforts to stimulate the immune system with the known interferon inducer poly(I:C
12
U) (Ampligen) offered only limited protection against lethal PCV challenge. Taken together, these data suggest that the increased potency of the bio-optimized interferon alfacon-1 molecule may be critical to the observed antiviral effects. These data are the first report demonstrating efficacious treatment of acute arenaviral disease with alpha interferon therapy, and further study is warranted.
Mosaic Structure of a Multiple-Drug-Resistant, Conjugative Plasmid from
Campylobacter jejuni
Authors: Nirdnoy Warawadee , Mason Carl J. , Guerry Patricia
Published: May 2005

Partial sequence analysis of a
tet
(O) plasmid from a multiple-drug-resistant clinical isolate of
Campylobacter jejuni
revealed 10 genes or pseudogenes encoding different aminoglycoside inactivating enzymes, transposase-like genes, and multiple unknown genes from a variety of pathogenic and commensal bacteria. The plasmid could be mobilized by a P incompatibility group plasmid into
Escherichia coli
, where it apparently integrated into the chromosome and expressed high-level resistance to multiple aminoglycoside antibiotics. This work provides new information about both the nature of drug resistance in
C. jejuni
and the ability of
C. jejuni
to exchange genes with other bacterial species.
Fluoroquinolone-Resistant
Streptococcus agalactiae
: Epidemiology and Mechanism of Resistance
Authors: Wehbeh Wehbeh , Rojas-Diaz Roberto , Li Xinying , Mariano Noriel , Grenner Louise , Segal-Maurer Sorana , Tommasulo Barbara , Drlica Karl , Urban Carl , Rahal James J.
Published: May 2005

Quinolone-resistant
Streptococcus agalactiae
bacteria were recovered from single-patient isolates and found to contain mutations in the gyrase and topoisomerase IV genes. Pulsed-field gel electrophoresis demonstrated that four isolates from the same long-term care facility were closely related; in seven cases, quinolone-resistant
Haemophilus influenzae
and
S. agalactiae
bacteria were isolated from the same patient.
In Vitro Activity and Killing Effect of Citropin 1.1 against Gram-Positive Pathogens Causing Skin and Soft Tissue Infections
Authors: Giacometti Andrea , Cirioni Oscar , Kamysz Wojciech , Silvestri Carmela , Del Prete Maria Simona , Licci Alberto , D'Amato Giuseppina , Łukasiak Jerzy , Scalise Giorgio
Published: May 2005

The in vitro activity of citropin 1.1 against gram-positive cocci was measured by MIC, minimal bactericidal concentration, time-kill studies, and a checkerboard titration method. Streptococci and staphylococci were inhibited at concentrations between 1 and 16 mg/liter, respectively. Enterococci showed less susceptibility. Synergy was demonstrated when citropin 1.1 was combined with clarithromycin and doxycycline.
In Vitro Activity of Doripenem (S-4661) against Multidrug-Resistant Gram-Negative Bacilli Isolated from Patients with Cystic Fibrosis
Authors: Chen Yunhua , Garber Elizabeth , Zhao Qiuqu , Ge Yigong , Wikler Matthew A. , Kaniga Koné , Saiman Lisa
Published: May 2005

Doripenem 50% inhibitory concentrations (MIC
50
) and 90% inhibitory concentrations (MIC
90
) for multidrug-resistant strains of mucoid
Pseudomonas aeruginosa
(
n
= 200 strains), nonmucoid
P. aeruginosa
(
n
= 200), and
Burkholderia cepacia
complex (
n
= 200) isolated from patients with cystic fibrosis were 8 and 32, 8 and 64, and 8 and 32 μg/ml, respectively. Doripenem had somewhat better activity than established antimicrobial agents.
Class I Integron with a Group II Intron Detected in an
Escherichia coli
Strain from a Free-Range Reindeer
Authors: Sunde Marianne
Published: May 2005

An
Escherichia coli
strain, isolated from wild reindeer in a remote mountain area, contained a class 1 integron with two unusual features: a group II intron and a cassette with homology to a superintegron cassette. Alignments indicate that
attC
sites of gene cassettes may be insertion sites for introns.
Isolation and Expression of a Novel Molecular Class D β-Lactamase, OXA-61, from
Campylobacter jejuni
Authors: Alfredson David A. , Korolik Victoria
Published: May 2005

A novel β-lactamase gene,
bla
OXA-61
, from
Campylobacter jejuni
GC015 was cloned and its nucleotide sequence determined.
bla
OXA-61
encodes a protein of 257 amino acids in which the active-site STFK tetrad and conserved class D β-lactamase motifs YGN and KTG were identified. A conserved sequence upstream of
bla
OXA-61
is required for expression in
Campylobacter
.
Multicenter Study of the Mechanisms of Resistance and Clonal Relationships of
Streptococcus agalactiae
Isolates Resistant to Macrolides, Lincosamides, and Ketolides in Spain
Authors: Gonzalez J. J. , Andreu A.
Published: May 2005

Macrolide, lincosamide, and ketolide mechanisms of resistance and clonal relationships were characterized in a collection of 79 resistant group B streptococcus isolates obtained from neonates or pregnant women. The
erm
(B),
erm
(TR), and
mef
(A) genes were present in 62%, 30.4%, and 3.8% of the isolates, respectively. There was considerable clonal diversity among them.
Selection of Cross-Resistance following Exposure of
Pseudomonas aeruginosa
Clinical Isolates to Ciprofloxacin or Cefepime
Authors: Alyaseen Samer A. , Piper Kerryl E. , Rouse Mark S. , Steckelberg James M. , Patel Robin
Published: May 2005

Exposure of ciprofloxacin- and cefepime-susceptible
Pseudomonas aeruginosa
isolates to increasing concentrations of ciprofloxacin selected for ciprofloxacin resistance in 26/27 and cefepime nonsusceptibility in 7/27 isolates. Exposure of the isolates to increasing concentrations of cefepime selected for cefepime nonsusceptibility in 20/27 isolates but not for ciprofloxacin resistance.
ErmB Determinants and Tn
916
-Like Elements in Clinical Isolates of
Clostridium difficile
Authors: Spigaglia Patrizia , Carucci Valentina , Barbanti Fabrizio , Mastrantonio Paola
Published: May 2005

Erythromycin and tetracycline resistance was analyzed in 37
Clostridium difficile
clinical isolates. Strains of different clonal origins showed different erythromycin and tetracycline resistance determinants and different genetic arrangements of the elements. In strains of recent isolation, the presence of Tn
916
-like elements, never found before in
C. difficile
clinical isolates, has been demonstrated.
Decreasing Prevalence of β-Lactamase Production among Respiratory Tract Isolates of
Haemophilus influenzae
in the United States
Authors: Heilmann Kris P. , Rice Cassie L. , Miller Ashley L. , Miller Norma J. , Beekmann Susan E. , Pfaller Michael A. , Richter Sandra S. , Doern Gary V.
Published: May 2005

A total of 986 isolates of
Haemophilus influenzae
from patients with respiratory tract infections in 45 United States medical centers were characterized during the winter of 2002-2003. β-Lactamase production was noted with 26.2% of isolates; 14.6% were resistant to trimethoprim-sulfamethoxazole. Resistance to other relevant antimicrobial agents was extremely uncommon. In comparison to the results of four previous national surveys conducted since 1994, the prevalence of β-lactamase production with this pathogen appears to be decreasing.
Posttreatment Changes in
Escherichia coli
Antimicrobial Susceptibility Rates among Diarrheic Patients Treated with Ciprofloxacin
Authors: Putnam Shannon D. , Sanders John W. , Tribble David R. , Rockabrand David R. , Riddle Mark S. , Rozmajzl Patrick J. , Frenck Robert W.
Published: May 2005

Changes in antimicrobial resistance of
Escherichia coli
among deployed U.S. military personnel being treated for diarrhea were evaluated. Stool samples were collected pretreatment and on days 7, 14, and 28 posttreatment. Resistance to ciprofloxacin was noted in 13.3% of baseline specimens, and rates of resistance against multiple antibiotics increased dramatically from baseline to day 7 and then tapered off to return to pretreatment levels by day 28, except for ciprofloxacin, suggesting that population accumulative usage of fluoroquinolones may result in an incremental increase in resistance rates.
BEST PRACTICE No 185Cytological and molecular diagnosis of lymphoma
Authors: Kocjan G
Published: May 2005

With the advances in molecular pathology, the cell as a morphological and functional unit has become essential in the diagnosis of lymphoma. Conventional staining, preparation, and interpretation of cells, as seen in fine needle aspiration cytology (FNAC), often used as a first line investigation of lymphadenopathy, is being supplemented with an array of immunocytochemical and molecular analyses, aimed not only at a more precise disease definition, but also at recognising factors that can predict prognosis and response to treatment. Accepting the pitfalls of conventional cytomorphology, this review looks at molecular changes characteristic to particular lymphomas and explores the currently available technology for their detection, with particular reference to cytological material. Future protocols for the diagnosis and management of patients with lymphadenopathy should include FNAC as an initial investigation, followed by immunocytochemistry and molecular investigations. Tissue biopsy, the conventional method of diagnosis, may be avoided in selected cases.
Large cell neuroendocrine carcinoma of the larynx: a case report and a review of the classification of this neoplasm
Authors: Greene L , Brundage W , Cooper K
Published: May 2005

This report describes a case of large cell neuroendocrine carcinoma (LCNEC) of the larynx. A 74 year old man who presented with otalgia underwent direct laryngoscopy with biopsy, which revealed an invasive poorly differentiated carcinoma. Laryngectomy with bilateral neck dissections revealed invasion of the pre-epiglottic space by the tumour, with metastases to bilateral lymph nodes (AJCC T3N2c). The tumour was characterised by large cells with vesicular chromatin and prominent nucleoli. The cells were arranged in organoid and trabecular patterns with a background of extensive necrosis and numerous mitotic figures. Immunohistochemical and ultrastructural analyses confirmed the neuroendocrine nature of the tumour. Metastatic disease was present in the liver, and the patient died within weeks of surgery. LCNEC carcinoma is a rare tumour of the larynx. Recognition at this site is essential so that proper patient management can be initiated.