bluuebunny/crossref_metadata_2025 huggingface dataset:
Predictive value of clinical, electrophysiological and immunological features for response to IVIg in patients with CIDP
Authors: Isoardo G , Rota E , Ciaramitaro P , Tavella A , Poglio F , Prolasso I , Cocito D
Published: April 2004

Aims: To investigate the features which are most predictive of IVIg response in patients with CIDP. Methods: We included 38 consecutive CIDP diagnosed according to Rotta et al. (2000). Anti‐MAG antibodies (Ab) assay and serum immunofixation were performed in all. IVIg (0.4 g/Kg/day) were the first treatment in all patients. Response to IVIg was defined as increase by at least 1 grade of the Rankin scale score at 1 month. The following features were considered: 1) proximal as well as distal weakness, 2) pure clinical sensory pattern, 3) disease duration lower than 12 months, 4) conduction block in at least 1 motor nerve, 5) mean lower/upper limbs motor nerve CMAP amplitude lower than 50% of lower limit of normal, 6)M monoclonal gammopathy, and 7) anti‐MAG Ab. Likelihood ratio (LR) of the features significantly associated with treatment response was evaluated in order to determine the increase or decrease of response to IVIg probability. Results: Twenty‐six patients were classified as responders and 12 as non‐responders. Age (60.6 ± 9.7 vs. 63.6 ± 9.4 years), disease duration (24 vs. 42 months) and sex ratio (18 vs. 9 male) were not different among the groups. Presence of conduction block in at least one motor nerve was associated significantly with treatment response (responders 50% vs. non‐responders 8.3%, p: 0.02) and presence of anti‐MAG Ab was associated with treatment failure (non‐responders 50% vs. responders 7.6%, p: 0.007). The remaining features were not significantly associated with treatment response. LR of presence on conduction block was 6, whereas LR of anti‐MAG Ab was 0.15. Considering 70% as mean percentage of responders, the finding of conduction blocks increase the probability of response to IVIg to 89%, whereas the finding of anti‐MAG antibody decreases this probability to 25%. Conclusion: Presence of conduction blocks and absence of anti‐MAG antibodies seem to be good predictors of response to IVIg in patients with CIDP.
CIDP associated with lung cancer: a paraneoplastic disease?
Authors: Fazio R , Malaguti MC , Molinari E , Previtali S , Del Carro U , Amadio S , Comi G , Quattrini A
Published: April 2004

We describe a 65‐year‐old smoker male followed for five years for a pure motor demyelinating peripheral neuropathy. The patient had a monthly motor relapse with severe weakness restricting him to a wheelchair, so he needed monthly high dose IVIg. On EMG the MCV were very slowed (30 m/sec) without evidence of conduction blocks while SCV were in the normal range. CSF disclosed a high protein level. Laboratory findings did not reveal any other abnormality except for the presence of monoclonal gammopathy IgMk and high titer anti GD1a serum IgM antibodies (1:5000). In March 2003 he had the most severe relapse with flaccid tetraplegia and respiratory failure so severe that he required ventilatory support. A total body CT scan revealed a nodular lung lesion with diffuse lymphangiitis. Biopsy disclosed a lung adenocarcinoma with a severe infiltration of CD8 cells. Surgical eradication of the tumor caused the last severe relapse. At the moment the patient is relapse‐free and no more treatment was administered. The clinical course of the motor demyelinating relapsing neuropathy suggests a possible paraneoplastic pathogenesis of the neurological illness also supported by the severe inflammatory infiltration of the tumor.
Paraneoplastic subacute sensory neuronopathy associated with anti‐ri antibodies
Authors: Fasolino M , Sabatini P , Cuomo T , Liguori G
Published: April 2004

Introduction: Subacute sensory neuronopathy (SSN) is characterized by degeneration of T cells of dorsal root ganglia. This syndrome is associated with autoimmune diseases (i.e., Sjogren's Syndrome), tumours (i.e., small‐cell lung cancer), or idiopathic. Paraneoplastic SSN is frequently associated with the presence in the serum of anti‐Hu antibodies (or ANNA 1). Conversely, anti‐Ri antibodies (or ANNA 2) have been associated with paraneoplastic neurological syndromes as opsoclonus‐myoclonus or cerebellar degeneration. Case Report: A 62‐year‐old man presented subacute back pain, gait difficulty, four limbs movement uncoordination and paresthesias/dysesthesias. Neurological examination also revealed involuntary pseudoathetoid movements at upper limbs, loss of vibration sense at lower limbs and diffuse absence of deep tendon reflexes. Nerve conduction studies revealed an axonal sensory polyneuropathy. Cerebrospinal fluid proteins were raised, with increased cell count. Chest CT disclosed a lung neoplasm. Serum anti‐Ri antibodies were detected using indirect immunofluorescence and confirmed by Western blotting, while anti‐Hu were absent. Conclusion: We report a case of paraneoplastic subacute sensory neuronopathy associated with serum anti‐Ri antibodies. To our knowledge this is the first description of such an association.
Is carpal tunnel syndrome surgery useful in patients with diabetes or autoimmune polyneuropathies?
Authors: Caliandro P , Mondelli M , Aprile I , Pazzaglia C , Sabatelli M , Tonali P , Padua L
Published: April 2004

In the neurological ‘out‐patient’ department, focused on neuropathies, we have to deal with two common diseases: diabetic neuropathy and autoimmune neuropathies. Carpal tunnel syndrome is the most frequent neurological syndrome. It is difficult to assess if, in a diffuse peripheral nerve involvement or in systemic condition that may involve nerves, as diabetes, an entrapment condition is a distinct entity, a co‐morbidity condition, or expression of a “locus minor resistentiae.” In clinical practice it is difficult to answer these questions: in autoimmune neuropathy patients and in diabetic patients, should we surgically treat nerve entrapment? Recently we provided evidence that a mechanical condition around the nerve, typical of the entrapment region, does not enhance autoimmune aggression in CIDP. Therefore, in CIDP patients a true entrapment, neurophysiologically demonstrated, could be a concomitant pathology and if a severe and persistent entrapment worsens functional deficit and symptoms, a surgical decompression could be useful. There is evidence that diabetic patients operated for carpal tunnel syndrome have the same post surgery evolution than non‐diabetic patients. In conclusion, in autoimmune neuropathies and diabetic patients, the physician should strongly consider the possibility of surgery.
The self‐care approach as a new tool in modern health care. carpal tunnel syndrome, an ideal model to evaluate the efficacy of an instructional video
Authors: Conti V , Pazzaglia C , Aprile I , Caliandro P , Tonali P , Padua L
Published: April 2004

Objective: The proliferation of medical knowledge (including media attention for health) and this emergence of chronic disease laid fertile ground for the self‐care movement and revision of the doctor‐patient relationship. The growing emphasis on self‐care has led to increasing needs for accurate patient information on alternative approaches to clinical problems. Carpal tunnel syndrome (CTS) is the most frequent focal neuropathy. Postures are relevant for development worsening or improvement of CTS. Hence, CTS exemplifies a pathology in which patients can be instructed by the use of a video, avoiding wrong positions that can worsen the pathology. Materials and Methods: We developed an instructional video for CTS patients to educate themselves on how to avoid postures that could worse the median nerve entrapment. Furthermore, we performed the first steps of validation. Results: The first steps of validation showed that the video is able to transfer the arguments we believe are relevant to avoid negative posture. To complete the validation, a randomised controlled trial is ongoing to evaluate the efficacy of the video. Discussion: We can imagine self‐care as a low‐cost program for promoting health self‐management, improving elements of health status while reducing care costs in populations with diverse chronic diseases. CTS is an ideal model to evaluate the efficacy of the self‐care approach. The developed video was able to instruct patients about the importance of posture on this disease and how to avoid/modify daily activities negative for the entrapment syndrome. Note that the use of the video was explicitly intended to augment the usual doctor‐patient interaction, not to substitute it.
Pegylated alpha‐interferons peripheral neurotoxicity: prospective study in chronic hepatitis C
Authors: Briani C , Zara G , Bernardinello L , Cavalletto L , Ermani M , Chemello L
Published: April 2004

Objective: To assess whether pegylated interferons (PEG‐IFNs) treatment is associated with occurrence, worsening or improvement of peripheral neuropathy in HCV patients. Background: Alpha‐IFN is associated with central nervous system side effects. There are reports of both improvement and worsening of neuropathy during alpha‐IFN treatment, but the possible alpha‐IFN peripheral neurotoxicity has never been consistently investigated. Patients and Methods: Twenty‐six HCV patients (19 male, 7 females, median age 41.5 ± 9.6 years) have been treated with PEG‐IFNs (alpha‐2a 180 mcg weekly or alpha‐2b 1.5 mcg, weekly) and ribavirin for 6–12 months. Eleven patients had neuropathy at recruitment (two diabetic, nine HCV‐related neuropathy, one with cryoglobulins). Before therapy (T0) all patients underwent quantitative viral RNA determination, HCV genotype analysis, liver biopsy, neurological and electrophysiological evaluation. Response amplitude and conduction velocities of median, ulnar, sural, and peroneal nerves were recorded. During therapy (T1)(mean follow‐up 7,8 ± 4.0 months), patients were neurologically and electrophysiologically re‐evaluated. Eighteen HCV patients (11 males, 7 females, median age 47.4 ± 9.6) with comparable viral load, not in IFN treatment, were studied as controls. Results: During PEG‐IFNs therapy, no significant differences of all electrophysiological parameters were detected between T0 and T1 evaluations (repeated measures ANOVA) in all 44 treated and non‐treated patients, also in those with neuropathy at recruitment. No correlations were found between electrophysiological parameters and length of therapy (Spearman's Rho). Conclusions: Peripheral neuropathy seems not to complicate PEG‐IFNs therapy in HCV patients. An ongoing follow‐up study on a larger group of patients will help confirm these results.
Expression of ciliary neurotrophic factor (CNTF) in charcot‐marie‐tooth type 1A (CMT1A) disease
Authors: Vigo T , Schenone A , Mancardi G , Abruzzese M , Timmerman V , Van Hummelen P , Nobbio L
Published: April 2004

cDNA microarray experiments on sciatic nerves from 30‐day‐old PMP22 transgenic (PMP22tg) rats were performed to detect genes modulated in CMT1A. Among the downregulated genes, CNTF mRNA was significantly reduced, whereas other neurotrophic factors (BDNF, NT3, NGF) and cognate receptors (TRKA, TRKB, TRKC) were unchanged. We further studied CNTF expression in transgenic nerves using an ELISA technique. We observed significantly (p < 0.001) lower concentrations of the protein in sciatic nerves from homozygous (59 ± 7.8 pg/mg of proteins) and heterozygous (140.8 ± 17.56 pg/mg of proteins) PMP22tg nerves compared to normal controls (713.8 ± 168.7 pg/mg of proteins). Moreover, using real time PCR, we studied CNTF expression in human sural nerves from 2 CMT1A patients and in 3 control nerves. According to the animal results, CNTF mRNA expression was absent in CMT1A patients whereas it was detectable in control nerves (1.99 ± 0.9). Finally, we studied CNTF mRNA expression in aging PMP22tg rats; preliminary results show a further decrease of CNTF mRNA in heterozygous transgenic rats compared to normal age‐matched littermates. Our results suggest that reduced CNTF expression may account for the development of axonal atrophy in CMT1A.
Rv1818c‐encoded PE_PGRS protein of Mycobacterium tuberculosis is surface exposed and influences bacterial cell structure
Authors: Delogu Giovanni , Pusceddu Cinzia , Bua Alessandra , Fadda Giovanni , Brennan Michael J. , Zanetti Stefania
Published: April 2004

Identification of the novel PE multigene family was an unexpected finding of the genomic sequencing of Mycobacterium tuberculosis. Presently, the biological role of the PE and PE_PGRS proteins encoded by this unique family of mycobacterial genes remains unknown. In this report, a representative PE_PGRS gene (Rv1818c/PE_PGRS33) was selected to investigate the role of these proteins. Cell fractionation studies and fluorescence analysis of recombinant strains of Mycobacterium smegmatis and M. tuberculosis expressing green fluorescent protein (GFP)‐tagged proteins indicated that the Rv1818c gene product localized in the mycobacterial cell wall, mostly at the bacterial cell poles, where it is exposed to the extracellular milieu. Further analysis of this PE_PGRS protein showed that the PE domain is necessary for subcellular localization. In addition, the PGRS domain, but not PE, affects bacterial shape and colony morphology when Rv1818c is overexpressed in M. smegmatis and M. tuberculosis. Taken together, the results indicate that PE_PGRS and PE proteins can be associated with the mycobacterial cell wall and influence cellular structure as well as the formation of mycobacterial colonies. Regulated expression of PE genes could have implications for the survival and pathogenesis of mycobacteria within the human host and in other environmental niches.
Cell envelope components contributing to biofilm growth and survival of Pseudomonas putida in low‐water‐content habitats
Authors: Van De Mortel Martijn , Halverson Larry J.
Published: April 2004

Bacteria in terrestrial habitats frequently reside as biofilm communities on surfaces that are unsaturated, i.e. biofilms are covered in water films varying in thickness depending on the environmental conditions. Water availability in these habitats is influenced by the osmolarity of the water (solute stress) and by cellular dehydration imposed by matric stress, which increases as water content decreases. Unfortunately, we understand relatively little about the molecular mechanisms required for bacterial growth in low‐water‐content habitats. Here, we describe the use of mini‐Tn5‐′phoA to identify genes in Pseudomonas putida that are matric water stress controlled and to generate mutants defective in desiccation tolerance. We identified 20 genes that were induced by a matric stress but not by a thermodynamically equivalent solute stress, 11 genes were induced by both a matric and a solute stress, three genes were induced by a solute stress and three genes were repressed by a matric stress. Their patterns of expression were analysed in laboratory media, and their contribution to desiccation tolerance was evaluated. Twenty‐six genes were homologous to sequences present in the completed P. putida KT2440 genome sequence or plasmid pWWO sequence that are involved in protein fate, nutrient or solute acquisition, energy generation, motility, alginate biosynthesis or cell envelope structure, and the function of five could not be predicted from the sequence. Together, these genes and their importance to desiccation tolerance provide a view of the environment perceived by bacteria in low‐water‐content habitats, and suggest that the mechanisms for adaptation for growth in low‐water‐content habitats are different from those for growth in high‐osmolarity habitats.
A novel enzyme, citryl‐CoA lyase, catalysing the second step of the citrate cleavage reaction in Hydrogenobacter thermophilus TK‐6
Authors: Aoshima Miho , Ishii Masaharu , Igarashi Yasuo
Published: April 2004

A novel enzyme catalysing citryl‐CoA cleavage to acetyl‐CoA and oxaloacetate was purified from Hydrogenobacter thermophilus TK‐6, and designated citryl‐CoA lyase (CCL). The citrate cleavage reaction in this organism proceeded by a unique set of two consecutive reactions: (i) citryl‐CoA formation by citryl‐CoA synthetase (CCS) and (ii) citryl‐CoA cleavage by CCL. Purified CCL gave a single 30 kDa band in SDS–PAGE and gel filtration chromatography indicated that the native state of the enzyme exists as a trimer (α3). Citryl‐CoA lyase showed low citrate synthase (CS) activity. Using an oligonucleotide probe, the corresponding gene was cloned and sequenced. The gene was expressed in Escherichia coli and recombinant CCL was also purified. The CCL protein sequence showed similarity to the C‐terminal regions of ATP citrate lyase (ACL) and CS sequences in the database. By further sequence comparisons, the phylogenetic relationship between CCS, CCL, ACL and CS was investigated.
The Aspergillus fumigatus transcriptional activator CpcA contributes significantly to the virulence of this fungal pathogen
Authors: Krappmann Sven , Bignell Elaine M. , Reichard Utz , Rogers Tom , Haynes Ken , Braus Gerhard H.
Published: April 2004

We have cloned and characterized the Aspergillus fumigatus cpcA gene encoding the transcriptional activator of the cross‐pathway control system of amino acid biosynthesis. cpcA encodes a functional orthologue of Saccharomyces cerevisiae Gcn4p. The coding sequence of the 2.2 kb transcript is preceded by two short upstream open reading frames, the larger one being well conserved among Aspergilli. Deletion strains in which either the coding sequence or the entire locus are replaced by a bifunctional dominant marker are impaired in their cross‐pathway control response upon amino acid starvation, as demonstrated by analyses of selected reporter genes and specific enzymatic activities. In a murine model of pulmonary aspergillosis, cpcAΔ strains display attenuated virulence. Pathogenicity is restored to wild‐type levels in strains with reconstitution of the genomic locus. Competitive mixed infection experiments additionally demonstrate that cpcAΔ strains are less able to survive in vivo than their wild‐type progenitor. Our data suggest that specific stress conditions are encountered by A. fumigatus within the mammalian host and that the fungal cross‐pathway control system plays a significant role in pulmonary aspergillosis.
Lipid‐induced filamentous growth in Ustilago maydis
Authors: Klose Jana , De Sá Mário Moniz , Kronstad James W.
Published: April 2004

The phytopathogenic fungus Ustilago maydis is obligately dependent on infection of maize to complete the sexual phase of its life cycle. Mating interactions between haploid, budding cells establish an infectious filamentous cell type that invades the host, induces large tumours and eventually forms large masses of black spores. The ability to switch from budding to filamentous growth is therefore critical for infection and completion of the life cycle, although the signals that influence the transition have not been identified from the host or the environment. We have found that growth in the presence of lipids promotes a filamentous phenotype that resembles the infectious cell type found in planta. In addition, the ability of the fungus to respond to lipids is dependent on both the cAMP signalling pathway and a Ras/MAPK pathway; these pathways are known to regulate mating, filamentous growth and pathogenesis in U. maydis. Overall, these results lead us to hypothesize that lipids may represent one of the signals that promote and maintain the filamentous growth of the fungus in the host environment.
Roles of CmpR, a LysR family transcriptional regulator, in acclimation of the cyanobacterium Synechococcus sp. strain PCC 7942 to low‐CO2 and high‐light conditions
Authors: Takahashi Yukari , Yamaguchi Osamu , Omata Tatsuo
Published: April 2004

The cmp operon of Synechococcus sp. strain PCC 7942, encoding a high‐affinity bicarbonate transporter, is induced under low CO2 conditions by a LysR family protein CmpR. CmpR was found to be required also for induction of the operon by transfer of the cells from low‐light to high‐light conditions, indicating involvement of a common mechanism in the high‐light‐ and low‐CO2‐responsive regulation. Expression of the high‐light inducible genes psbAII and psbAIII, on the other hand, was found to be induced also by low‐CO2 conditions. A single promoter was responsible for the high‐light and low‐CO2 induction of each of psbAII and psbAIII, suggesting involvement of a common regulatory mechanism in the light and CO2 responses of the psbA genes. CmpR was, however, not required for the induction of psbAII and psbAIII, indicating the presence of multiple mechanisms for induction of genes under high‐light and low‐CO2 conditions. The CmpR‐deficient mutant nevertheless showed lower levels of the psbAII and psbAIII transcripts than the wild‐type strain under all the light and CO2 conditions examined. Gel shift assays showed that CmpR binds to the enhancer elements of psbAII and psbAIII, through specific interaction with a sequence signature conforming to the binding motif of similar LysR family proteins. These findings showed that CmpR acts as a trans‐acting factor that enhances transcription of the photosystem II genes involved in acclimation to high light, revealing a complex network of gene regulation in the cyanobacterium.
Identification of the Entner–Doudoroff pathway in an antibiotic‐producing actinomycete species
Authors: Gunnarsson Nina , Mortensen Uffe H. , Sosio Margherita , Nielsen Jens
Published: April 2004

The metabolic network of the central carbon metabolism represents the backbone of cellular metabolism and provides the precursors and cofactors required for synthesis of secondary metabolites. It is therefore pivotal to map the operating metabolic network in the central carbon metabolism in order to design metabolic engineering strategies towards construction of more efficient producers of specific metabolites. In this context, methods that allow rapid and reliable mapping of the central carbon metabolism are valuable. In the present study, a 13C labelling‐based method was used to identify the primary metabolic pathways of the poorly characterized antibiotic‐producing actinomycete Nonomuraea sp. ATCC 39727. Surprisingly, it was found that Nonomuraea sp. ATCC 39272 predominantly metabolizes glucose via the Entner–Doudoroff (ED) pathway. This represents the first time that the ED pathway has been recognized as the main catabolic pathway in an actinomycete. The Nonomuraea genes encoding the key enzymes of the ED pathway were subsequently identified, sequenced and functionally described.
Population trends and damage patterns of Hypsipyla grandella (Lepidoptera: Pyralidae) in a mahogany stand, in Turrialba, Costa Rica
Authors: Taveras Rosina , Hilje Luko , Hanson Paul , Mexzón Ramón , Carballo Manuel , Navarro Carlos
Published: April 2004

Abstract  1 Population trends of Hypsipyla grandella and their relationship with abiotic (humidity, precipitation and temperature) and biotic factors (availability of mahogany shoots and natural mortality agents), as well as damage patterns, were studied for 16 months in Turrialba, Costa Rica.

2 Hypsipyla grandella was active in the field all year round, and its population density was influenced by temperature, availability of new shoots and natural mortality agents.

3 It was possible to predict four population peaks, which appeared approximately every 1881 degree‐days.

4 Even though H. grandella larvae mainly attack shoots, they also fed on the bark of the bole, especially when green shoots were scarce.

5 Four parasitoid species were recorded (Bracon c. chontalensis, Brachymeria c. conica, Apanteles sp. and Dolichogenidea sp.) but their impact on H. grandella abundance was negligible.
Characterization of western corn rootworm (Coleoptera: Chrysomelidae) population dynamics in relation to landscape attributes
Authors: Beckler Amber A. , French B. Wade , Chandler Laurence D.
Published: April 2004

Abstract  1 The western corn rootworm (WCR), Diabrotica virgifera virgifera Leconte (Coleoptera: Chrysomelidae), creates economic and environmental concerns in the Corn Belt region of the U.S.A. To supplement the population control tactics of the Areawide Pest Management Program in Brookings, South Dakota, Geographical Information Systems (GIS) were used to examine the spatial relationships from 1997 to 2001 between WCR population dynamics, habitat structure, soil texture and elevation.

2 Using the inverse distance weighted interpolation technique, WCR population density maps were created from georeferenced emergence and post‐emergence traps placed in maize fields. For each year, these maps were overlaid with vegetation, soil and elevation maps to search for quantitative relationships.

3 Through visual interpretation and correlation analysis, shifts in landscape structure, such as size, number and arrangement of patches, were shown to associate with WCR population abundance and distribution in varying degrees. Contingency analysis showed that WCR population abundance is associated with soil texture and elevation.

4 An understanding of the interactions between WCR population dynamics and landscape variables provides information to pest managers, and this can be used to identify patterns in the landscape that promote high insect population density patches to improve pest management strategies.
‘Beetle banks’ as refuges for beneficial arthropods in farmland: long‐term changes in predator communities and habitat
Authors: MacLeod A. , Wratten S. D. , Sotherton N. W. , Thomas M. B.
Published: April 2004

Abstract  1 Significant differences in the overwintering densities of predatory carabid and staphylinid beetles and spiders occurred on an ‘island’ grassy bank habitat composed of blocks of Agrostis stolonifera, Dactylis glomerata, Holcus lanatus and Lolium perenne, within and between winters during a 7‐year study.

2 Densities of the predators over the last three winters of the study were greater in the bank than in the boundary of the field in which the bank was situated.

3 Succession occurred in plots of L. perenne, with D. glomerata fully replacing this species. Plots of D. glomerata and H. lanatus remained virtually mono‐specific.

4 Over the period of study, the beetle bank maintained its role in providing overwintering habitat for polyphagous predators and carabid diversity has increased since the bank was first established. Beetle banks were therefore shown to contribute to conservation biodiversity in an agroecosystem.
Immunomodulation confers herbicide resistance in plants
Authors: Almquist Kurt C. , Niu Yongqing , McLean Michael D. , Mena Frank L. , Yau Kerrm Y. F. , Brown Kirk , Brandle Jim E. , Hall J. Christopher
Published: April 2004

In order to create a novel mechanism for herbicide resistance in plants, we expressed a single‐chain antibody fragment (scFv) in tobacco with specific affinity to the auxinic herbicide picloram. Transgenic tobacco plants and seedlings expressing this scFv against picloram were protected from its effect in a dose‐dependent manner. This is the first successful use of an antibody to confer in vivo resistance to a low molecular weight xenobiotic (i.e. < 1000 Da). Our results suggest the possibility for a generic antibody‐based approach to create crops resistant to low molecular weight xenobiotics for subsequent use in the bioremediation of contaminated soils, crop protection and as novel selectable markers.
Conformational analysis of hepatitis B surface antigen fusions in an Agrobacterium‐mediated transient expression system
Authors: Huang Zhong , Mason Hugh S.
Published: April 2004

Vaccine antigens have been successfully produced in transgenic plants for oral immunization. Recently, a fusion strategy has been adopted to produce multicomponent vaccines and to target antigens to mucosal sites for enhanced oral immunogenicity. However, antigen fusions may not be folded correctly due to steric hindrance and may thus lose their potency. Here, we describe an Agrobacterium‐mediated transient assay that provides enough antigen‐expressing material at 2 days post‐transfection to evaluate antigen conformation. Using the hepatitis B surface antigen (HBsAg) as a model antigen and the green fluorescent protein (GFP) as a model fusion partner, we showed that transiently expressed HBsAg and an HBsAg fusion with GFP at the N‐terminus (GFP:HBsAg), but not the HBsAg fusion with GFP at the C‐terminus (HBsAg:GFP), formed the ‘a’ determinant and virus‐like particles (VLPs), similar to yeast‐derived vaccine HBsAg. Thus, it is feasible to modify the HBsAg with an N‐terminal fusion of up to 239 amino acids without altering its major antigenic properties. Our results also demonstrate that the Agrobacterium‐mediated transient expression system can be used to evaluate the conformation of plant‐based vaccines or other pharmaceutical proteins in a high‐throughput manner.
Urea standard Kt/Vurea for assessing dialysis treatment adequacy
Authors: Leypoldt John K
Published: April 2004

Urea standard Kt/Vurea (stdKt/Vurea) has been proposed as a dose measure to assess the adequacy of dialysis treatments of arbitrary length and frequency. It is based on two fundamental assumptions: 1) that clinical outcomes for hemodialysis and peritoneal dialysis patients are equivalent and 2) that the equivalency of such clinical outcomes is achieved when the mean predialysis blood urea nitrogen or urea concentration is identical for both therapies. The relationships among urea stdKt/Vurea, equilibrated Kt/Vurea, and single‐pool Kt/Vurea are reviewed, and the assumptions required for the validity of urea stdKt/Vurea as a universal dose measure to describe dialysis treatment adequacy are discussed. It is proposed that urea stdKt/Vurea is a dose measure for both water‐soluble and protein‐bound toxin clearances; therefore, this parameter may be a practical dose measure for assessing the adequacy of dialysis during treatments of arbitrary length and frequency.
Firm Organization and the Structure of Retail Markets
Authors: Dinlersoz Emin M.
Published: April 2004

This paper analyzes the structure of retail markets by highlighting the differential pattern exhibited across local markets by two different types of firm organization: chain stores versus stand‐alone stores. Data from retail alcoholic beverage industry in California suggest that the number of chain stores is proportional to city size. Further evidence on the sales of establishments indicates that average size of a stand‐alone store virtually is invariant to city size, whereas chain stores appear to get larger as city size increases. Theories consistent with these findings are discussed.
CD8αα-Mediated Survival and Differentiation of CD8 Memory T Cell Precursors
Authors: Madakamutil Loui T. , Christen Urs , Lena Christopher J. , Wang-Zhu Yiran , Attinger Antoine , Sundarrajan Monisha , Ellmeier Wilfried , von Herrath Matthias G. , Jensen Peter , Littman Dan R. , Cheroutre Hilde
Published: April 2004

Memory T cells are long-lived antigen-experienced T cells that are generally accepted to be direct descendants of proliferating primary effector cells. However, the factors that permit selective survival of these T cells are not well established. We show that homodimeric α chains of the CD8 molecule (CD8αα) are transiently induced on a selected subset of CD8αβ
+
T cells upon antigenic stimulation. These CD8αα molecules promote the survival and differentiation of activated lymphocytes into memory CD8 T cells. Thus, memory precursors can be identified among primary effector cells and are selected for survival and differentiation by CD8αα.
The Fine-Scale Structure of Recombination Rate Variation in the Human Genome
Authors: McVean Gilean A. T. , Myers Simon R. , Hunt Sarah , Deloukas Panos , Bentley David R. , Donnelly Peter
Published: April 2004

The nature and scale of recombination rate variation are largely unknown for most species. In humans, pedigree analysis has documented variation at the chromosomal level, and sperm studies have identified specific hotspots in which crossing-over events cluster. To address whether this picture is representative of the genome as a whole, we have developed and validated a method for estimating recombination rates from patterns of genetic variation. From extensive single-nucleotide polymorphism surveys in European and African populations, we find evidence for extreme local rate variation spanning four orders in magnitude, in which 50% of all recombination events take place in less than 10% of the sequence. We demonstrate that recombination hotspots are a ubiquitous feature of the human genome, occurring on average every 200 kilobases or less, but recombination occurs preferentially outside genes.
Synfire Chains and Cortical Songs: Temporal Modules of Cortical Activity
Authors: Ikegaya Yuji , Aaron Gloster , Cossart Rosa , Aronov Dmitriy , Lampl Ilan , Ferster David , Yuste Rafael
Published: April 2004

How can neural activity propagate through cortical networks built with weak, stochastic synapses? We find precise repetitions of spontaneous patterns of synaptic inputs in neocortical neurons in vivo and in vitro. These patterns repeat after minutes, maintaining millisecond accuracy. Calcium imaging of slices reveals reactivation of sequences of cells during the occurrence of repeated intracellular synaptic patterns. The spontaneous activity drifts with time, engaging different cells. Sequences of active neurons have distinct spatial structures and are repeated in the same order over tens of seconds, revealing modular temporal dynamics. Higher order sequences are replayed with compressed timing.
Life Among the Formulae of Physics
Authors: Vincent Julian F. V.
Published: April 2004

Comparative Biomechanics
Life's Physical World. by Steven Vogel. Princeton University Press, Princeton, NJ, 2003. 592 pp. $60, £39.95. ISBN 0-691-11297-5.

In this comprehensive introduction to biomechanics, Vogel covers both fluid and solid mechanics as well as the properties of biological materials. With his usual style and wit, he discusses the use of methods and models adapted from physics and mechanical engineering to explore how organisms move and function.
Pulsars in Binary Systems: Probing Binary Stellar Evolution and General Relativity
Authors: Stairs Ingrid H.
Published: April 2004

Radio pulsars in binary orbits often have short millisecond spin periods as a result of mass transfer from their companion stars. They therefore act as very precise, stable, moving clocks that allow us to investigate a large set of otherwise inaccessible astrophysical problems. The orbital parameters derived from high-precision binary pulsar timing provide constraints on binary evolution, characteristics of the binary pulsar population, and the masses of neutron stars with different mass-transfer histories. These binary systems also test gravitational theories, setting strong limits on deviations from general relativity. Surveys for new pulsars yield new binary systems that increase our understanding of all these fields and may open up whole new areas of physics, as most spectacularly evidenced by the recent discovery of an extremely relativistic double-pulsar system.
MicroRNA-Directed Cleavage of
HOXB8
mRNA
Authors: Yekta Soraya , Shih I-hung , Bartel David P.
Published: April 2004

MicroRNAs (miRNAs) are endogenous ∼22-nucleotide RNAs, some of which are known to play important regulatory roles in animals by targeting the messages of protein-coding genes for translational repression. We find that miR-196, a miRNA encoded at three paralogous locations in the A, B, and C mammalian HOX clusters, has extensive, evolutionarily conserved complementarity to messages of
HOXB8, HOXC8
, and
HOXD8
. RNA fragments diagnostic of miR-196–directed cleavage of
HOXB8
were detected in mouse embryos. Cell culture experiments demonstrated down-regulation of
HOXB8, HOXC8, HOXD8
, and
HOXA7
and supported the cleavage mechanism for miR-196–directed repression of
HOXB8
. These results point to a miRNA-mediated mechanism for the posttranscriptional restriction of HOX gene expression during vertebrate development and demonstrate that metazoan miRNAs can repress expression of their natural targets through mRNA cleavage in addition to inhibiting productive translation.
Prevention and Cure of Systemic
Escherichia coli
K1 Infection by Modification of the Bacterial Phenotype
Authors: Mushtaq Naseem , Redpath Maria B. , Luzio J. Paul , Taylor Peter W.
Published: April 2004

Escherichia coli
is a common cause of meningitis and sepsis in the newborn infant, and the large majority of isolates from these infections produce a polysialic acid (PSA) capsular polysaccharide, the K1 antigen, that protects the bacterial cell from immune attack. We determined whether a capsule-depolymerizing enzyme, by removing this protective barrier, could alter the outcome of systemic infection in an animal model. Bacteriophage-derived endosialidase E (endoE) selectively degrades the PSA capsule on the surface of
E. coli
K1 strains. Intraperitoneal administration of small quantities of recombinant endoE (20 μg) to 3-day-old rats, colonized with a virulent strain of K1, prevented bacteremia and death from systemic infection. The enzyme had no effect on the viability of
E. coli
strains but sensitized strains expressing PSA to killing by the complement system. This study demonstrates the potential therapeutic efficacy of agents that cure infections by modification of the bacterial phenotype rather than by killing or inhibition of growth of the pathogen.
Identification and Characterization of Inhibitors of Bacterial Enoyl-Acyl Carrier Protein Reductase
Authors: Ling Losee L. , Xian Jun , Ali Syed , Geng Bolin , Fan Jun , Mills Debra M. , Arvanites Anthony C. , Orgueira Hernan , Ashwell Mark A. , Carmel Gilles , Xiang Yibin , Moir Donald T.
Published: April 2004

Bacterial enoyl-acyl carrier protein reductase (ENR) catalyzes an essential step in fatty acid biosynthesis. ENR is an attractive target for narrow-spectrum antibacterial drug discovery because of its essential role in metabolism and its sequence conservation across many bacterial species. In addition, the bacterial ENR sequence and structural organization are distinctly different from those of mammalian fatty acid biosynthesis enzymes. High-throughput screening to identify inhibitors of
Escherichia coli
ENR yielded four structurally distinct classes of hits. Several members of one of these, the 2-(alkylthio)-4,6-diphenylpyridine-3-carbonitriles (“thiopyridines”), inhibited both purified ENR (50% inhibitory concentration [IC
50
] = 3 to 25 μM) and the growth of
Staphylococcus aureus
and
Bacillus subtilis
(MIC = 1 to 64 μg/ml). The effect on cell growth is due in part to inhibition of fatty acid biosynthesis as judged by inhibition of incorporation of [
14
C]acetate into fatty acids and by the increased sensitivity of cells that underexpress an ENR-encoding gene (four- to eightfold MIC shift). Synthesis of a variety of compounds in this chemical series revealed a correlation between IC
50
and MIC, and the results provided initial structure-activity relationships. Preliminary structure-activity relationships, potency on purified ENR, and activity on bacterial cells indicate that members of the thiopyridine chemical series are effective fatty acid biosynthesis inhibitors suitable for further antibacterial development.
Pharmacokinetics of Adjusted-Dose Lopinavir-Ritonavir Combined with Rifampin in Healthy Volunteers
Authors: la Porte C. J. L. , Colbers E. P. H. , Bertz R. , Voncken D. S. , Wikstrom K. , Boeree M. J. , Koopmans P. P. , Hekster Y. A. , Burger D. M.
Published: April 2004

Coadministration of lopinavir-ritonavir, an antiretroviral protease inhibitor, at the standard dose (400/100 mg twice a day [BID]) with the antituberculous agent rifampin is contraindicated because of a significant pharmacokinetic interaction due to induction of cytochrome P450 3A by rifampin. In the present study, two adjusted-dose regimens of lopinavir-ritonavir were tested in combination with rifampin. Thirty-two healthy subjects participated in a randomized, two-arm, open-label, multiple-dose, within-subject controlled study. All subjects were treated with lopinavir-ritonavir at 400/100 mg BID from days 1 to 15. From days 16 to 24, the subjects in arm 1 received lopinavir-ritonavir at 800/200 mg BID in a dose titration, and the subjects in arm 2 received lopinavir-ritonavir at 400/400 mg BID in a dose titration. Rifampin was given at 600 mg once daily to all subjects from days 11 to 24. The multiple-dose pharmacokinetics of lopinavir, ritonavir, and rifampin were assessed. Twelve of 32 subjects withdrew from the study. For nine subjects lopinavir-ritonavir combined with rifampin resulted in liver enzyme level elevations. Pharmacokinetic data for 19 subjects were evaluable. Geometric mean ratios for the lopinavir minimum concentration in serum and the maximum concentration in serum (
C
max
) on day 24 versus that on day 10 were 0.43 (90% confidence interval [CI], 0.19 to 0.96) and 1.02 (90% CI, 0.85 to 1.23), respectively, for arm 1 (
n
= 10) and 1.03 (90% CI, 0.68 to 1.56) and 0.93 (90% CI, 0.81 to 1.07), respectively, for arm 2 (
n
= 9). Ritonavir exposure increased from days 10 to 24 in both arms. The geometric mean
C
max
of rifampin was 13.5 mg/liter (day 24) and was similar between the two arms. Adjusted-dose regimens of lopinavir-ritonavir in combination with therapeutic drug monitoring and monitoring of liver function may allow concomitant use of rifampin.
In Vitro Antifungal Activities of Inhibitors of Phospholipases from the Fungal Pathogen
Cryptococcus neoformans
Authors: Ganendren Ranjini , Widmer Fred , Singhal Vatsala , Wilson Christabel , Sorrell Tania , Wright Lesley
Published: April 2004

Secreted phospholipase B is a proven virulence factor for the pathogenic fungus
Cryptococcus neoformans
and exhibits three phospholipase activities in the one protein. These are phospholipase B (PLB), lysophospholipase (LPL), and lysophospholipase transacylase (LPTA). Our aim was to investigate the feasibility of using this enzyme as a target for antifungal therapy. We determined in
C. neoformans
var.
grubii
strain H99 that 82% of PLB activity was secreted but that 64% of LPL activity and 70% of LPTA activity were cell associated. Cell-associated activities (cytosolic and membrane) were further characterized, since it is likely that any fungicidal effect would depend on inhibition of these enzymes. Four commercially available compounds with structural similarities to phospholipid substrates were tested as inhibitors. These were alexidine dihydrochloride (compound A), dioctadecyldimethylammonium bromide (compound O), 1,12 bis-(tributylphosphonium)dodecane dibromide (compound P), and decamethonium dibromide (compound D). The best phospholipase inhibitors (compounds A and P) were also the most potent antifungal agents by the standard broth microdilution test. Compound A was highly selective for secreted and cell-associated PLB activities and showed no inhibition of mammalian phospholipase
A
2
at 0.25 μM. Compound O, which was specific for secretory and cytosolic LPL and LPTA and membrane-associated PLB, was not antifungal. We conclude that inhibitors of cryptococcal phospholipases can be selective for fungal enzymes and intrinsically antifungal. They also provide tools for assessing the relative importance of the various enzyme activities in virulence. Our results enable further rational structure-function studies to validate the use of phospholipases as antifungal targets.
Biophysical Characterization of Endotoxin Inactivation by NK-2, an Antimicrobial Peptide Derived from Mammalian NK-Lysin
Authors: Andrä Jörg , Koch Michel H. J. , Bartels Rainer , Brandenburg Klaus
Published: April 2004

NK-2, a membrane-acting antimicrobial peptide, was derived from the cationic core region of porcine NK-lysin and consists of 27 amino acid residues. It adopts an amphipathic, α-helical secondary structure and has been shown to interact specifically with membranes of negatively charged lipids. We therefore investigated the interaction of NK-2 with lipopolysaccharide (LPS), the main, highly anionic component of the outer leaflet of the outer membrane of gram-negative bacteria, by means of biophysical and biological assays. As model organisms and a source of LPS, we used
Salmonella enterica
strains with various lengths of the LPS carbohydrate moiety, including smooth LPS, rough LPS, and deep rough LPS (LPS Re) mutant strains. NK-2 binds to LPS Re with a high affinity and induces a change in the endotoxin-lipid A aggregate structure from a cubic or unilamellar structure to a multilamellar one. This structural change, in concert with a significant overcompensation of the negative charges of LPS, is thought to result in the neutralization of the endotoxic LPS activity in a cell culture system. Neutralization of LPS activity by NK-2 as well as its antibacterial activity against the various
Salmonella
strains strongly depends on the length of the sugar chains of LPS, with LPS Re being the most sensitive. This suggests that a hydrophobic peptide-LPS interaction is necessary for efficient neutralization of the biological activity of LPS and that the long carbohydrate chains, besides their function as a barrier for hydrophobic drugs, also serve as a trap for polycationic substances.
Feasibility of Radioimmunotherapy of Experimental Pneumococcal Infection
Authors: Dadachova E. , Burns T. , Bryan R. A. , Apostolidis C. , Brechbiel M. W. , Nosanchuk J. D. , Casadevall A. , Pirofski L.
Published: April 2004

Streptococcus pneumoniae
is an important cause of community-acquired pneumonia, meningitis, and bacteremia. The problem of pneumococcal disease is exacerbated by increasing drug resistance. Furthermore, patients with impaired immunity are at high risk for invasive pneumococcal infections. Thus, there is an urgent need for new approaches to antimicrobial therapy. Antibody therapies take advantage of the specificity and high affinity of the antigen-antibody interaction to deliver antibacterial compounds to a site of infection in the form of naked or conjugated antibodies. We have recently established that radioimmunotherapy (RIT) can be used to treat experimental fungal infections in mice. In the present study, we investigated the feasibility of applying a RIT approach to the treatment of
S. pneumoniae
infection by evaluating the susceptibility of
S. pneumoniae
to radiolabeled antibody in vitro and in an animal infection model. For the specific antibody carrier, we used human monoclonal antibody D11, which binds to pneumococcal capsular polysaccharide 8. We have selected the alpha particle emitter
213
Bi as the radionuclide for conjugation to the antibody. Incubation of serotype 8
S. pneumoniae
with
213
Bi-D11 resulted in dose-dependent killing of bacteria. RIT of
S. pneumoniae
infection in C57BL/6 mice showed that 60% more mice survived in the
213
Bi-D11-treated group (80 μCi) than in the untreated group (
P
< 0.01). The treatment did not cause hematological toxicity, as demonstrated by platelet counts. This feasibility study establishes that RIT can be applied to the treatment of bacterial infections.
Mechanism of Action of the Ribopyranoside Benzimidazole GW275175X against Human Cytomegalovirus
Authors: Underwood Mark R. , Ferris Robert G. , Selleseth Dean W. , Davis Michelle G. , Drach John C. , Townsend Leroy B. , Biron Karen K. , Boyd F. Leslie
Published: April 2004

New human cytomegalovirus (HCMV) therapies with novel mechanisms of action are needed to treat drug-resistant HCMV that arises during therapy with currently approved agents. 2-Bromo-5,6-dichloro-1-β-
d
-ribofuranosyl-1
H
-benzimidazole (BDCRB) is an effective anti-HCMV agent with a novel mechanism of action, but problems with in vivo stability preclude clinical development. A
d
-ribopyranosyl derivative of BDCRB, GW275175X, displays similar antiviral activity without the in vivo stability problems. We present an initial description of the activity of GW275175X against HCMV, other herpesviruses, and selected nonherpesviruses. In addition, we show that it acts as a DNA maturation inhibitor like the parent compound, BDCRB, rather than via the mechanisms of action of 1263W94 or any anti-HCMV drugs approved for marketing. GW275175X is a promising candidate for clinical development as an anti-HCMV agent.