bluuebunny/crossref_metadata_2025 huggingface dataset:
In vivo magnetic resonance imaging of iron oxide–labeled, arterially‐injected mesenchymal stem cells in kidneys of rats with acute ischemic kidney injury: Detection and monitoring at 3T
Authors: Ittrich Harald , Lange Claudia , Tögel Florian , Zander Axel R. , Dahnke Hannes , Westenfelder Christof , Adam Gerhard , Nolte‐Ernsting Claus
Published: May 2007

Purpose

To evaluate MRI for a qualitative and quantitative in vivo tracking of intraaortal injected iron oxide–labeled mesenchymal stem cells (MSC) into rats with acute kidney injury (AKI).

Materials and Methods

In vitro MRI and R2* measurement of nonlabeled and superparamagnetic iron oxide (SPIO)‐labeled MSC (MSCSPIO) was performed in correlation to cellular iron content and cytological examination (Prussian blue, electron microscopy). In vivo MRI and R2* evaluation were performed before and after ischemic/reperfusion AKI (N = 14) and intraaortal injection of 1.5 × 106 MSCSPIO (N = 7), fetal calf serum (FCS) (medium, N = 6), and SPIO alone (N = 1) up to 14 days using a clinical 3T scanner. Signal to noise ratios (SNR), R2* of kidneys, liver, spleen, and bone marrow, renal function (creatinine [CREA], blood urea nitrogen [BUN]), and kidney volume were measured and tested for statistical significance (Student's t‐test, P < 0.05) in comparison histology (hematoxylin and eosin [H&E], Prussian blue, periodic acid‐Schiff [PAS], CD68).

Results

In vitro, MSCSPIO showed a reduction of SNR and T2* with R2* ≈ number of MSCSPIO (R2 = 0.98). In vivo MSCSPIO administration resulted in a SNR decrease (35 ± 15%) and R2* increase (101 ± 18.3%) in renal cortex caused by MSCSPIO accumulation in contrast to control animals (P < 0.01). Liver, spleen, and bone marrow (MSCSPIO) showed a delayed SNR decline/R2* increase (P < 0.05) resulting from MSCSPIO migration. The increase of kidney volume and the decrease in renal function (P < 0.05) was reduced in MSC‐treated animals.

Conclusion

Qualitative and quantitative in vivo cell‐tracking and monitoring of organ distribution of intraaortal injected MSCSPIO in AKI is feasible in MRI at 3T. J. Magn. Reson. Imaging 2007;25:1179–1191. © 2007 Wiley‐Liss, Inc.
Black‐blood T2* technique for myocardial iron measurement in thalassemia
Authors: He Taigang , Gatehouse Peter D. , Kirk Paul , Tanner Mark A. , Smith Gillian C. , Keegan Jennifer , Mohiaddin Raad H. , Pennell Dudley J. , Firmin David N.
Published: May 2007

Purpose

To compare the effectiveness and reproducibility of a new black‐blood sequence vs. a conventional bright‐blood gradient‐echo T2* sequence for myocardial iron overload measurement in thalassemia.

Materials and Methods

Twenty thalassemia patients were studied. Black‐blood sequence images were acquired in diastole after a double inversion recovery (DIR) preparation pulse. Bright‐blood sequence images were acquired in both early systole and late diastole. The data were randomized and the T2* analysis was performed blindly by two independent observers.

Results

The T2* values from the black‐blood sequence were comparable to those of the conventional bright‐blood sequence (25.7 ± 12.9 msec vs. 26.4 ± 14.2 msec in early systole, P = 0.44; and 25.2 ± 13.1 msec in late diastole, P = 0.41). The coefficient of variation (CV) for black‐blood image T2* analysis was 4.1% compared with 8.9% (early systole P = 0.03) and 7.8% (late diastole P = 0.05) for bright‐blood image analysis.

Conclusion

The black‐blood T2* technique yields high‐contrast myocardial images, provides clearly depicted myocardial borders, and avoids blood signal contamination of the myocardium while yielding improvements in interobserver variability. J. Magn. Reson. Imaging 2007;25:1205–1209. © 2007 Wiley‐Liss, Inc.
Staining methods for magnetic resonance microscopy of the rat fetus
Authors: Petiet Alexandra , Hedlund Laurence , Johnson G. Allan
Published: May 2007

Purpose

To develop a magnetic resonance histology (MRH) staining and fixation method by immersion to enhance the signal‐to‐noise ratio (SNR) with a paramagnetic contrast agent permitting microscopic acquisition within a 3‐hour scan time.

Materials and Methods

Methods were optimized for embryonic day 18.5 (E18.5) rat fetuses and imaging at 9.4T with an RF refocused spin‐echo pulse sequence (TR/TE = 75 msec/5.2 msec). Fixation/staining was performed by immersion in Bouin's fixative containing varied concentrations of ProHance (from 10:1 to 500:1 Bouin's:ProHance) and for varied immersion durations (up to 24 hours).

Results

The results showed a significant change in T1 and T2 relaxation times as a function of concentration of contrast agent and immersion duration. As the contrast agent penetrated the tissues, T1 was reduced as desired (typically by 10×), but at the same time T2 was profoundly reduced (typically by 3×) due to both protein cross‐linking from the fixative and the high concentration of contrast agent. A systematic assessment of this staining protocol showed an increased SNR (by 5×) over that in unstained specimens.

Conclusion

This staining protocol reduced scan time for very‐high‐resolution images (19.5 μm) to only 3 hours, making MRH a routine tool for evaluating fetal development. J. Magn. Reson. Imaging 2007;25:1192–1198. © 2007 Wiley‐Liss, Inc.
Three‐dimensional gradient‐echo imaging for percutaneous MR‐guided laser therapy of liver metastasis
Authors: Puls Ralf , Stroszczynski Christian , Rosenberg Christian , Kuehn Jens‐Peter , Hegenscheid Katrin , Speck Ulrich , Stier Albrecht , Hosten Norbert
Published: May 2007

Purpose

To evaluate the use of three‐dimensional (3D) gradient‐echo (GRE) magnetic resonance imaging (MRI) for percutaneous MR‐guided catheter placement for laser therapy of liver metastases.

Materials and Methods

Thirty‐four patients were included. A total of 122 MR‐guided percutaneous punctures of 67 liver metastases were performed on a 1.5T scanner (Symphony and Sonata; Siemens, Erlangen, Germany) using a 5.5F microcatheter system and titanium needle (Monocath; MeoMedical, Augsburg, Germany). In 88 of 122 procedures, a 2D fast low‐angle shot (FLASH) T1‐weighted GRE breath‐hold sequence was acquired in the axial plane and if necessary in a second plane. Sequences were acquired and reviewed using the panel in the control room. In 34 of 122 procedures a 3D FLASH T1‐weighted fat‐saturated GRE (volume‐interpolated breath‐hold examination (VIBE)) sequence was acquired in the axial plane only. Acquisition and 3D review were controlled under sterile conditions with a panel inside the examination room (Syngo; Siemens).

Results

The 3D FLASH sequence significantly decreased the mean number of acquisitions needed to place the microcatheter with the titanium needle in the metastasis compared to interventions with the 2D FLASH sequence (2.9 ± 0.83 vs. 4.4 ± 1.63). With 2D FLASH imaging, acquisition in a second plane was necessary in 78 instances (20% of acquired 2D sequences) to ensure adequate positioning of the device during the procedure. The artifact caused by the titanium needle was smaller with the 3D FLASH sequence. The conspicuity of liver metastases and morphology (liver edge and vessels) was acceptable with both sequences. The 3D FLASH sequence improved differentiation when two to four titanium needles were inserted, due to smaller susceptibility artifacts caused by the needles.

Conclusion

3D GRE imaging with the capability to perform multiplanar reconstruction (MPR) shortens the procedure by reducing the number of sequences needed. Improved visibility of the titanium needles allows more precise insertion of multiple needles into the metastasis. J. Magn. Reson. Imaging 2007;25:1174–1178. © 2007 Wiley‐Liss, Inc.
Genotypes and molecular epidemiology of human astroviruses in hospitalized children with acute gastroenteritis in Rio de Janeiro, Brazil
Authors: Victoria Matías , Carvalho‐Costa Filipe Aníbal , Heinemann Marcos Bryan , Leite José Paulo Gagliardi , Miagostovich Marize Pereira
Published: May 2007

Human astrovirus (HAstV) is an important pathogen that causes acute gastroenteritis mainly in children up to 5 years old worldwide. A total of 318 fecal samples were collected from January to December of 2004 from children with acute gastroenteritis hospitalized in Rio de Janeiro (RJ), Brazil. The samples were obtained from three public hospitals and were previously investigated for the presence of rotavirus (RV) and enteric adenovirus (AdV). The aim of this study was to determine the prevalence and molecular characterization of HAstV by reverse‐transcription polymerase chain reaction (RT‐PCR) and partial sequencing of open reading frame 2 (ORF2). HAstV infections were detected in 43 (14%) of the samples, of which 19 (6%) were mixed infections with HAstV and RV. HAstV were identified in all age groups, with 85% of the cases occurring in children younger than 2 years old. HAstV infections were more prevalent from March to May. Diarrhea, vomiting, and fever were the main clinical manifestations observed in these infections. Partial capsid sequencing of 35 HAstV strains characterized 25 (71%) as genotype 1 (HAstV‐1), 6 (17%) HAstV‐2, 3 (9%) HAstV‐8, and 1 (3%) HAstV‐4. Based on the genetic variability, three lineages were observed between RJ HAstV‐1 strains. This study demonstrated the importance of HAstV infections causing acute infantile gastroenteritis in hospitalized children in RJ, Brazil. Molecular epidemiological surveillance is helpful for designing prevention strategies of HAstV transmission. J. Med. Virol. 79:939–944, 2007. © 2007 Wiley‐Liss, Inc.
Review: hepatitis B immune globulin for prevention of hepatitis B infection
Authors: Zuckerman J.N.
Published: May 2007

Specific hepatitis B immune globulin (HBIG) contains a high titer of antibody to hepatitis B surface antigens and provides immediate passive protection against infection with hepatitis B virus, after acute exposure to infection. It is now generally combined with active immunization with hepatitis B vaccine. The principal indications for administration of HBIG are: a single acute percutaneous exposure to hepatitis B virus (HBV); mucocutaneous exposure; unprotected sexual exposure; mother‐to‐infant transmission; prevention of re‐infection after liver transplantation; non‐responders to hepatitis B vaccine and immunosuppressed patients. J. Med. Virol. 79:919–921, 2007. © 2007 Wiley‐Liss, Inc.
Evolution of viral load and changes of polymerase and precore/core promoter sequences in lamivudine‐resistant hepatitis B virus during adefovir therapy
Authors: Chang U Im , Lee Young Chun , Wie Seong Heon , Jang Jeong Won , Bae Si Hyun , Choi Jong Young , Yang Jin Mo , Yoon Seung Kew , Sun Hee Sik
Published: May 2007

Adefovir dipivoxil (ADV) has demonstrated clinical activity against both wild‐type and lamivudine‐resistant hepatitis B virus (HBV). We analyzed the evolution of viral load and the changes of polymerase and precore/core promoter sequences in lamivudine‐resistant virus during ADV therapy. The authors studied 14 patients who had breakthrough hepatitis after lamivudine therapy. Serial sera were obtained prior to adefovir administration and at 3, 6 and 12 months after ADV therapy. Nucleotide sequences of polymerase and the precore/core promoter from the hepatitis B virus were analyzed. The median serum HBV DNA decrease with adefovir treatment was 4.35 log10 copies/mL at 12 months. Tyrosine‐methionine‐aspartate‐aspartate (YMDD) mutants were found in 12 patients among the 14 patients with lamivudine resistance. The YMDD mutant viruses reversed to the wild‐type in 6 patients out of the 12 patients after 3–6 months of ADV after discontinuing lamivudine therapy. In the analysis of the nucleotide sequences of the precore/core promoter gene, core promoter mutants in 12 patients were replaced by wild‐type virus in three patients (25%), while precore mutants in four patients were replaced by the wild‐type in three patients (75%). The results demonstrate the patterns of polymerase and precore/core promoter mutations in lamivudine‐resistant hepatitis B viruses and the reversion from the mutant to the wild‐type in some patients. In addition, despite several mutations in the polymerase during ADV therapy, ADV effectively suppressed HBV replication without the emergence of resistant viral mutants. J. Med. Virol. 79:902–910, 2007. © 2007 Wiley‐Liss, Inc.
Molecular epidemiology of acute hepatitis B in the Netherlands in 2004: nationwide survey
Authors: van Houdt R. , Bruisten S.M. , Koedijk F.D.H. , Dukers N.H.T.M. , Op de Coul E.L.M. , Mostert M.C. , Niesters H.G.M. , Richardus J.H. , de Man R.A. , van Doornum G.J.J. , van den Hoek J.A.R. , Coutinho R.A. , van de Laar M.J.W. , Boot H.J.
Published: May 2007

To gain insight into hepatitis B virus (HBV) transmission in the Netherlands, epidemiological data and sera were collected from reported cases of acute HBV infections in the Netherlands in 2004. Cases were classified according to mode of transmission. A fragment of the S‐gene of HBV (648 bp) was amplified, sequenced, and subjected to phylogenetic analysis. Of the 291 acute HBV cases reported in 2004, 158 (54%) were available for genotyping. Phylogenetic analysis identified 6 genotypes: A (64%), B (3%), C (3%), D (21%), E (5%) and F (5%). Of HBV infected men having sex with men, 86% were infected with genotype A, accounting for 43% of all patients infected with this genotype. There were only three reported cases of injecting drug use of which one was available for sequencing (genotype A). Unlike the genotype A cluster, sequences within the genotype B–E clusters were heterogenic. Within genotype F, several isolates had identical sequences, but patients could not be epidemiologically linked. Sexual transmission, particularly by men having sex with men was the most important transmission route for HBV. Injecting drug use plays a minor role. Genotype A is predominant in the Netherlands, especially among men having sex with men. In addition to imported strains, there seems to be a pool of related but non‐identical strains circulating among chronic carriers in the migrant population, from which occasionally new patients are infected, primarily by heterosexual transmission. J. Med. Virol. 79:895–901, 2007. © 2007 Wiley‐Liss, Inc.
Human herpesvirus 6‐associated retrobulbar optic neuritis in an HIV‐infected patient: response to anti‐herpesvirus therapy and long‐term outcome
Authors: Méchaï Frédéric , Boutolleau David , Manceron Véronique , Gasnault Jacques , Quertainmont Yann , Brosseau Jean‐Paul , Delfraissy Jean‐François , Labetoulle Marc , Goujard Cécile
Published: May 2007

Like other herpesviruses, human herpesvirus 6 (HHV‐6) can reactivate in immunocompromised patients. A case is described of an HIV‐1‐infected patient who developed bilateral retrobulbar optic neuritis associated with HHV‐6 infection. A 59‐year‐old woman, infected with HIV for 18 years, interrupted antiretroviral treatment because of therapeutic failure and severe metabolic complications. She presented subsequently with blurred vision and ophthalmological examination showed visual loss due to optic neuritis. Her CD4+ count was 285 cells/mm3 and her plasma HIV‐1 RNA level was 5.5 log10 copies (cp)/ml. Magnetic resonance imaging of the brain was normal. HHV‐6 loads were 3.2 log cp/ml in cerebrospinal fluid (CSF) and 6.3 log cp/106 peripheral blood mononuclear cells. Combined intravenous treatment was started with foscarnet and ganciclovir then changed to cidofovir and long‐term valganciclovir. Her ocular condition improved gradually despite little decrease of the HHV‐6 load in the CSF. Salvage antiretroviral treatment was then administered, with marked immunological and virological responses, contributing to further progressive ocular improvement. HHV‐6‐related optic neuritis has not been described previously in HIV‐infected patients. Anti‐HHV‐6 treatment improved the patient's vision, but immune restoration seems to remain essential for long‐term recovery. J. Med. Virol. 79:931–934, 2007. © 2007 Wiley‐Liss, Inc.
Anti‐retroviral drug resistance‐associated mutations among non‐subtype B HIV‐1‐infected Kenyan children with treatment failure
Authors: Lwembe Raphael , Ochieng Washingtone , Panikulam Annie , Mongoina Charles O. , Palakudy Tresa , Koizumi Yusuke , Kageyama Seiji , Yamamoto Naohiko , Shioda Tatsuo , Musoke Rachel , Owens Mary , Songok Elijah M. , Okoth Frederick A. , Ichimura Hiroshi
Published: May 2007

Recently increased availability of anti‐retroviral therapy (ART) has mitigated HIV‐1/AIDS prognoses especially in resource poor settings. The emergence of ART resistance‐associated mutations from non‐suppressive ART has been implicated as a major cause of ART failure. Reverse transcriptase inhibitor (RTI)‐resistance mutations among 12 non‐subtype B HIV‐1‐infected children with treatment failure were evaluated by genotypically analyzing HIV‐1 strains isolated from plasma obtained between 2001 and 2004. A region of pol‐RT gene was amplified and at least five clones per sample were analyzed. Phylogenetic analysis revealed HIV‐1 subtype A1 (n = 7), subtype C (n = 1), subtype D (n = 3), and CRF02_AG (n = 1). Before treatment, 4 of 12 (33.3%) children had primary RTI‐resistance mutations, K103N (n = 3, ages 5–7 years) and Y181C (n = 1, age 1 year). In one child, K103N was found as a minor population (1/5 clones) before treatment and became major (7/7 clones) 8 months after RTI treatment. In 7 of 12 children, M184V appeared with one thymidine‐analogue‐associated mutation (TAM) as the first mutation, while the remaining 5 children had only TAMs appearing either individually (n = 2), or as TAMs 1 (M41L, L210W, and T215Y) and 2 (D67N, K70R, and K219Q/E/R) appearing together (n = 3). These results suggest that “vertically transmitted” primary RTI‐resistance mutations, K103N and Y181C, can persist over the years even in the absence of drug pressure and impact RTI treatment negatively, and that appearing patterns of RTI‐resistance mutations among non‐subtype B HIV‐1‐infected children could possibly be different from those reported in subtype B‐infected children. J. Med. Virol. 79:865–872, 2007. © 2007 Wiley‐Liss, Inc.
Molecular evidence of father‐to‐child transmission of hepatitis B virus
Authors: Tajiri Hitoshi , Tanaka Yasuhito , Kagimoto Seiiti , Murakami Jun , Tokuhara Daisuke , Mizokami Masashi
Published: May 2007

At present in Japan, only high‐risk infants born to chronic hepatitis B virus (HBV)‐infected mothers are given HBV vaccine. However, children can contract the virus from other HBV‐infected family members, including fathers. The aim of this study is to present substantial and unequivocal evidence of father‐to‐child transmission of HBV infection using techniques including homology analysis and phylogenetic analysis. Thirteen chronic HBV‐infected members of five families that included eight children and their respective fathers were enrolled in this study. Homology analysis and phylogenetic analyses of 2 coding region, the S gene and X gene, from the HBV genome were performed comparing the 13 nucleotide sequences from the 13 subjects. The nucleotide homology among the five sets of fathers and children was quite high (99.3–100%). A phylogenetic tree constructed on the 13 nucleotide sequences showed that all 5 sets of fathers and children were grouped into the same cluster with high bootstrap values. These results strongly indicate that father‐to‐child transmission is an important route of HBV infection in Japan and it is recommend that universal vaccination against HBV infection be instituted immediately in Japan for all children, in accordance with the WHO recommendation of 1997. J. Med. Virol. 79:922–926, 2007. © 2007 Wiley‐Liss, Inc.
Epidemiologic aspects and laboratory features of enterovirus infections in Western Germany, 2000–2005
Authors: Roth Bernhard , Enders Martin , Arents Annette , Pfitzner Artur , Terletskaia‐Ladwig Elena
Published: May 2007

From 2000 to 2005, a total of 1,096 enterovirus infections were diagnosed either by isolation of virus from cell culture or by RT‐PCR (5′non‐coding region (NCR)). Typing of viruses (n = 674) was carried out by immunofluorescence with monoclonal antibodies, neutralization test or molecular methods. Seasons with high enterovirus activity were characterized by high prevalence of echovirus 30 (62.2% in 2000, 25.5% in 2001) and echovirus 13 (34.5% in 2001). In contrast, in the 2003 season, which had very low enterovirus activity, these types were rare. During this season, cell culture sensitivity (human colonic carcinoma cells and human embryonic lung fibroblasts (HEL)) was exceptionally low. In order to determine the type of “non‐cultivable” enteroviruses, purified RNA from selected stool samples was subjected to direct molecular typing. VP1/2A‐specific fragments were amplified by RT‐PCR, cloned and sequenced. The predominant virus identified was coxsackie A. Consequently, rhabdomyosarcom cells were introduced into the daily routine, which improved the isolation of enteroviruses. Echovirus 30 was again most commonly isolated during seasons 2004 and 2005 with increasing enterovirus activity. In conclusion, high prevalence of echovirus 30 and 13 is indicative of seasons with high enterovirus activity. The type of circulating enteroviruses may influence isolation of enterovirus from cell culture. RT‐PCR (VP1/2A) combined with cloning and sequencing of amplicons is a useful tool for viral typing directly from stool samples. In cases of severe enterovirus infection, virological diagnosis should not solely rely on virus isolation from cell culture. J. Med. Virol. 79:956‐962, 2007. © 2007 Wiley‐Liss, Inc.
Brazilian P[8],G1, P[8],G5, P[8],G9, and P[4],G2 rotavirus strains: Nucleotide sequence and phylogenetic analysis
Authors: Araújo Irene Trigueiros , Assis Rosane M. Santos , Fialho Alexandre Madi , Mascarenhas Joana D'Arc P. , Heinemann Marcos Bryan , Leite José Paulo G.
Published: May 2007

Rotavirus epidemiological surveys with molecular analysis of strains are required for gastroenteritis control and prevention. Twenty‐nine human rotavirus strains detected in Rio de Janeiro, Brazil, from 1986 to 2004 were characterized as P[8],G1, P[8],G5, P[8],G9, and P[4],G2 genotypes. The VP7 genes were sequenced and phylogenetic analysis was performed. Strains of genotype G1 revealed two distinct lineages, G1‐3 and G1‐4; strains of genotype G2 grouped in lineage G2‐1; G5 strains clustered with other Brazilians G5 strains and G9 strains were closely related to each other in lineage G9‐3, distinct from the original G9 strains detected in 1980s. The VP4 genes were analyzed and P[8] strains fell into two major genetic lineages, P[8]‐2 and P[8]‐3. Our findings document an intragenotype diversity represented by lineages and sublineages within rotavirus circulating in Rio de Janeiro from 1986 to 2004, before application of a vaccine (Rotarix®) in Brazil. This report emphasizes the importance of continuing monitor genotypes to verify if uncommon strains or newly strains are emerging to be specifically addressed in future vaccine trials. J. Med. Virol. 79:995‐1001, 2007. © 2007 Wiley‐Liss, Inc.
Group A rotavirus strains circulating in the eastern center of Tunisia during a ten‐year period (1995–2004)
Authors: Chouikha A. , Fodha I. , Noomen S. , Bouzid L. , Mastouri M. , Peenze I. , De Beer M. , Dewar J. , Geyer A. , Sfar T. , Gueddiche N. , Messaadi F. , Trabelsi A. , Boujaafar N. , Steele A. D.
Published: May 2007

An epidemiological survey investigating rotavirus infections in children was undertaken in the Eastern Center of Tunisia between January 1995 and December 2004. A total of 982 faecal specimens collected from children less than 5 years in age were screened by enzyme‐linked immunosorbent assay (ELISA) or latex agglutination assay for the presence of group A rotavirus antigen. Rotavirus‐positive samples were used for G and P typing by multiplex semi‐nested reverse transcription‐PCR. Rotaviruses were detected in 22% (n = 220) of stools. Of these, 164 were typed for VP7: G genotypes found were G1 (59%), G2 (2%), G3 (9%), G4 (10%), G8 (1%), and G9 (1%). Sixteen specimens (9%) showed mixed G profiles. A total of 119 specimens were typed for VP4. P genotypes detected were P[8] (32%), P[6] (15%), and P[4] (13%). Mixed P profiles were also detected (6%). Although the distribution of the detected genotypes appeared to change annually, G1P[8] rotavirus strains always predominated during the 10‐year period of study. This is the first report of rotaviruses in Tunisia with unconventional VP7 serotypes such as G8 and G9, highlighting the need for continual surveillance of emerging strains in Northern Africa. Indeed, the new commercial vaccines only contain the VP7 genes that dictate G1 or G1 to G4 specificities. These vaccines may protect less well against unusual strains circulating in countries planning to implement a rotavirus vaccine strategy. J. Med. Virol. 79:1002‐1008, 2007. © 2007 Wiley‐Liss, Inc.
Sequence analysis of the VP7 gene of human rotavirus G1 isolated in Japan, China, Thailand, and Vietnam in the context of changing distribution of rotavirus G‐types
Authors: Trinh Quang Duy , Nguyen Tuan Anh , Phan Tung Gia , Khamrin Pattara , Yan Hainian , Le Hoang Phuc , Maneekarn Niwat , Li Yan , Yagyu Fumihiro , Okitsu Shoko , Ushijima Hiroshi
Published: May 2007

Over the last decade, rotavirus G1 has represented the most common genotype worldwide. Since 2000, the prevalence of rotavirus G1 has decreased in some countries such as Japan and China. To monitor the trend of the VP7 encoding gene of rotavirus G1, we performed a sequence analysis of 74 G1 rotavirus strains isolated in Japan, China, Thailand, and Vietnam during the period from 2002 to 2005. The phylogenetic tree showed that all of the studied G1 strains from the four countries clustered into lineage III, the same as the majority of the G1 strains isolated in China and Japan in 1990 and 1991. Examination of the deduced amino acid sequences of the G1 strains from China and Japan revealed an amino acid substitution at position 91 (Asn instead of Thr) in antigenic region A when compared to the G1 strains isolated in China and Japan in 1990, 1991, and global reference strains. For the G1 strains from Thailand and Vietnam, there were three amino acid substitutions, not belonging to any antigenic regions. The study showed that there have been no considerable changes of human rotavirus G1 isolated in Japan, China, Thailand, and Vietnam. Further studies need to be carried out for a better understanding of why such changes in the prevalence of rotavirus G1 occur in these countries. J. Med. Virol. 79:1009‐1016, 2007. © 2007 Wiley‐Liss, Inc.
Genetic and phenotypic diversity of echovirus 30 strains and pathogenesis of type 1 diabetes
Authors: Paananen A. , Savolainen‐Kopra C. , Kaijalainen S. , Vaarala O. , Hovi T. , Roivainen M.
Published: May 2007

Several enterovirus serotypes should be considered as potentially diabetogenic. The capacity of an enterovirus to kill or impair the functions of human β‐cells can vary among the strains within a given serotype as shown previously for echovirus 9 and 30 (E‐30). The evolution of E‐30 has also shown patterns correlating with the global increase of type 1 diabetes incidence. In the present study, antigenic properties of a set of E‐30 isolates were investigated and the results correlated with the previously documented β‐cell destructive phenotype of the strains, or to genetic clustering of the strains. No simple correlation between the three properties was observed. A full‐length infectious clone was constructed and sequenced from one of the isolates found to be most destructive to β‐cells (E‐30/14916net87). Phylogenetic analyses demonstrated that this strain was closely related to the E‐30 prototype strain at the capsid coding region while outside the capsid region prototype strains of several other human enterovirus B serotypes clustered more closely. This suggests that the relatively greater pathogenicity of the strain might be based on properties of the genome outside of the structural protein coding region. Neutralizing antibody assays on sera from 100 type 1 diabetic patients and 100 controls using three different E‐30 strains did not reveal differences between the groups. This finding does not support a previous proposition of aberrant antibody responses to E‐30 in diabetic patients. It is concluded that identification of the genetic counterparts of pathogenicity of E‐30 strains requires further studies. J. Med. Virol. 79:945‐955, 2007. © 2007 Wiley‐Liss, Inc.
A note on the temporal and spatial variability of rainfall in the drought‐prone Amhara region of Ethiopia
Authors: Bewket Woldeamlak , Conway Declan
Published: May 2007

The aim of this study is to characterise rainfall variability and trend in the drought‐prone Amhara Regional State of Ethiopia using standard rainfall statistical descriptors. A review of previous studies of Ethiopian rainfall shows different conclusions between studies about the existence of trends primarily due to their use of different periods of analysis. Various rainfall indicator series are presented and analysed for trend on annual, seasonal and daily time steps (including wet‐day amounts and probabilities, percentiles and dry spell lengths). Two periods are used for analysis: 1975–2003 (12 stations) to optimise station density and 1961–2003 (five stations) to optimise record length in this relatively poorly monitored region.

A complex picture of rainfall variability emerges from the analysis, both in terms of spatial variability and temporal variability, from decadal to daily timescales. The results generally support those of the previous studies in Ethiopia with the additional findings that: (1) High levels of spatial variability exist at subregional scales in Ethiopia that are unlikely to be fully explained by large‐scale climate influences; (2) Choice of study period strongly influences the results of trend analysis in this region due to the effects of decadal variability (particularly because the 1980s was the driest decade and the 1990s the wettest decade on record); (3) Annual rainfall in the region recovered during the 1990s, although 2001–2003 were average or slightly lower; and (4) There are no consistent emergent patterns or trends in daily rainfall characteristics in this part of Ethiopia. Copyright © 2007 Royal Meteorological Society
Mapping snow characteristics based on snow observation probability
Authors: Saghafian Bahram , Davtalab Rahman
Published: May 2007

Measurement/estimation of snow water equivalent (SWE) is a difficult task in water resources studies of snowy regions. SWE point data is measured at snow courses that are normally operated with low density owing to high costs and great difficulty in reaching the stations in cold seasons. Moreover, snow is known to exhibit high spatial variability, which makes SWE studies based solely on sparse station data more uncertain. Ever‐increasing availability of satellite images is a promising tool to overcome some of the difficulties associated with analyzing spatial variability of snow. Although National Oceanic and Atmospheric Administration (NOAA) satellite images have low spatial resolution with approximately 1.1‐km pixel size, they are adequate for mapping snow cover at regional scales and enjoy a moderate length of record period. In this paper, rain and snow records of synoptic stations and the time series of NOAA‐based snow cover maps were used to map average SWE of a vast area in southwestern Iran. First, monthly and annual snow coefficient (SC) at synoptic stations were determined on the basis of analysis of hourly observation of type and amount of precipitation. Then, two new spatially distributed snow characteristics were introduced, namely, average frequency of snow observation (FSO) and monthly frequency of maximum snow observation (FMSO), on the basis of existing satellite snow observations. FSO and monthly FMSO maps were prepared by a geographic information system on the basis of snow map time series. Correlation of these two parameters with SC was studied and spatial distribution of SC was estimated on the basis of the best correlation. Moreover, the distribution of mean annual precipitation was derived by comparing a number of interpolation methods. SWE map was generated by multiplying SC and precipitation maps and its spatial variability in the region was analyzed. Copyright © 2007 Royal Meteorological Society
The prevalence and risk factors of post‐inflammatory hyperpigmentation after fractional resurfacing in Asians
Authors: Chan Henry H.L. , Manstein D. , Yu C.S. , Shek S. , Kono T. , Wei W.I.
Published: May 2007

Background

Ablative laser resurfacing is considered to be the main therapeutic option for the treatment of wrinkles and acne scarring. However, in Asians, post‐inflammatory hyperpigmentation (PIH) is a common adverse effect of laser resurfacing. Fractional resurfacing is a new concept of skin rejuvenation whereby zones of micro thermal injury are generated in the skin with the use of a 1,540‐nm laser. The risk and prevalence of hyperpigmentation in dark‐skinned patients using this approach have not been studied.

Objective

To assess the prevalence and risk factors of PIH that is associated with the use of fractional resurfacing in Asians.

Method

A retrospective study of 37 Chinese patients who were treated with fractional resurfacing for acne scarring, skin rejuvenation, and pigmentation was carried out. In all of the cases, pre‐ and post‐treatment clinical photographs (from standardized and cross‐polarized views) were taken using the Canfield CR system. Two independent observers assessed the photographs. A prospective study of treatments of nine different density and energy levels that were applied to the forearms of 18 volunteers was also performed. Clinical photographs were assessed pre‐ and post‐treatment for evidence of PIH.

Result

In the retrospective study, 119 treatment sessions were performed. Sixty‐eight treatment sessions were high energy, low density; 51 sessions were low energy, high density. Patients who underwent a high energy but low‐density treatment (range of energy 7–20 mJ; average energy 16.3 mJ, 1,000 MTZ) were associated with a lower prevalence of generalized PIH (7.1% vs. 12.4%) than those who underwent a low energy but high‐density (range of energy 6–12 mJ; average energy 8.2 mJ, 2,000 MTZ) treatment. However, the difference was not statistically significant. Localized PIH occurred in the peri‐oral area among patients who did not receive air cooling as an adjunctive therapy.

Conclusion

Both the density and energy of the treatment determines the risk of PIH in dark‐skinned patients. Density may be of more important but further studies are necessary to determine this. Cooling to prevent bulk tissue heating is also important, especially in small anatomical areas. By using adequate parameters, the risk of PIH in dark‐skinned patients can be significantly reduced. Lasers Surg. Med. © 2007 Wiley‐Liss, Inc.
Innovation and pricing in the Dutch drug industry
Authors: Reekie W. Duncan
Published: May 2007

The Dutch pharmaceutical industry is characterized by a high degree of innovative rivalry resulting in frequent rises and falls in market shares by both firms and products. Conventional concentration ratios, Herfindahl indices and market share stability measures are not highly correlated. The market, however, does display price sensitivity. Elasticity of demand for new products is inversely related to their incremental quality and directly related to their age.
Which statistical technique should i use? a survey and marketing case study
Authors: Doutriaux J. , Crener Maxime A.
Published: May 2007

Mini and microcomputers are putting an even larger number of powerful statistical analysis techniques at the disposal of the researcher. This paper uses a case study approach to show how to use the original objectives and purpose of a research project to design the study, organize the data collection and select the most appropriate multi‐variate technique. Multiple regression, correlation analysis, principal component and factor analysis, discriminant analysis, causal link analysis, cluster analysis, analysis of variance including automatic interaction detection, and canonical correlation analysis are among the models and statistical techniques described in terms of their requirements, underlying hypotheses, limits, advantages. The use of these techniques is illustrated by the study of the “enjoyment” of the tourists who visited the province of Quebec in 1975.
Industry analysis and investment decision‐making under conditions of uncertainty
Authors: Feldman Stanley J.
Published: May 2007

Evaluating risk is a key element in successful investment decision‐making. A major risk in forecasting company performance is associated with projecting its cash flow streams by product‐line which in turn is strongly related to the expected industry outlook and likely variability about this outlook. This paper sets out a methodology for evaluating this aspect of the investment decision by developing measures of expected real cash flow growth (reward) and expected annual variability of this growth (risk). These measures are constructed for 77 industry classifications at the two and three digit SIC (Standard Industrial Classification) level of detail by solving a dynamic input–output model under various economic secenarios. Aside from producing results which are relevant for producing company valuation bands, the analysis strongly suggests that perceptions of which industries are ‘winners’ and which are ‘losers’ are significantly altered when both ‘reward’ and ‘risk’ are used as criteria as opposed to either one alone. Finally, the methodology also produces results which measures the sources of cash flow growth in terms of relative price performance, productivity, and demand for output. Since there measures can be used as indicators of the quality of industry real cash flow growth, industry performance can be further arrayed within the broad categories of winning and losing industries. Several examples of how this is done are offered.
Cash management economies in the production of food
Authors: Koshal Manjulika , Koshal Rajindar K.
Published: May 2007

This study suggests that the behavior of demand of cash by business firms can better be understood by empirical testing theory on data derived from individual units rather than making unrealistic assumptions to justify testing of aggregated data. Using data for firms in the food industry, this study shows that the rate of interest is a significant variable in explaining the demand for cash. Furthermore, the statistical results indicate that the economies of scale in the management of cash depends upon the type of goods produced by the corporations under study. Accordingly, one cannot make any generalization regarding the question of the economies of scale in the management of cash.
Late entry, market shares and competitive survival: The case of synthetic fibers
Authors: Shaw Richard W. , Shaw Susan A.
Published: May 2007

This paper examines product policy in relation to the experience curve and product life cycle concepts in the context of the experience of the thirteen major firms in the Western European synthetic fibers industry. It examines the hypothesis based on Boston Consulting Group and the Profit Impact of Market Share (PIMS) evidence that late entrants to a market will be at a competitive disadvantage because they lack the accumulated experience of the pioneering firms. For each of the three main synthetic fibres, acrylic, nylon and polyester, it was found that the early entrants who established major market shares early in the growth phase of the product life cycle were able to maintain that leadership nearly twenty years later. In contrast not only did almost all the late entrants fail to achieve significant market shares but in the difficult market conditions between 1974 and 1981 they provided seven out of nine market withdrawals.
Diversification strategy and systematic risk: An empirical inquiry
Authors: Thompson R. S.
Published: May 2007

This paper presents some empirical tests of the impact of strategic diversification on a market‐based measure of firm risk. Instead of considering merely the consequences of isolated diversifying mergers, as most previous work in this area has done, the study examines the impact of all quoted acquisitions over a five year period using a sample of 100 large companies and a period of intense merger activity. The results cast further doubt on risk reduction as a general motive for diversifying merger, although they do not support the positive association between systematic risk and conglomerate status found in many US studies.
Using data envelopment analysis to measure the efficiency of non‐profit organizations: A critical evaluation
Authors: Nunamaker Thomas R.
Published: May 2007

This study examines the potential effects of variable set expansion and data variations upon the efficiency scores generated using the Data Envelopment Analysis (DEA) model. It was found that variable set expansion (either through disaggregation of existing variables or addition of new factors) should produce an upward trend in efficiency scores. In addition, ample opportunity exists for ‘decision‐making units’ to increase their efficiency scores through manipulation of reported data. In real‐world applications of DEA, these problems must be resolved as much as possible (e.g. increased audit of data) in order to improve DEA's practical usefulness and reliability.
The magnitude and reliability of equity capital cost estimates: A statistical approach
Authors: Thompson Howard E.
Published: May 2007

The purpose of this paper is to illustrate a simple technique of estimating the cost of equity capital as well as a statistical measure of its reliability. The approach specifies a probability structure that is readily estimated from company dividend data, and front that structure both the estimated cost of capital and its standard error are calculated.
Diversification and R & D activity in Japanese manufacturing firms
Authors: Doi Noriyuki
Published: May 2007

This his paper examines the influence of diversification on R & D intensity in Japanese manufacturing firms. Then alternative definitions of the diversification index are used. The results show that diversification is not a factor favorable to R & D activity. The finding that advertising intensity is positively and significantly related to R & D activity should also be noted.
Rate‐base valuation methods and firm efficiency
Authors: Bubnys Edward L. , Primeaux Walter J.
Published: May 2007

The economic performance of public utilities under different rate‐base valuation methods is examined in this paper. A unique procedure, involving Ordinary Least Squares regression analysis, examined data for all usable firms in states which have changed rate‐base methods since World War II. The sample consists of 20 electric firms extending over 30 years of time‐series data. Equations for individual firms were run to capture the effects of changes on rate‐base methods on capital intensity and capacity utilization on each separate business.

Contrary to expectations, there was no clear pattern indicating that firms in the sample increased the rate of capital intensity when their rate‐base method was changed to fair value from original cost. Similarly, expected excess capacity was not found under fair‐value regulation.

The general conclusion is that there is no reason to believe that different rate‐base valuation methods induce allocative inefficiency. Nevertheless, inefficiency may already exist in regulated monopolies in the form of X‐inefficiency.
An agency perspective of the firm's life‐cycle
Authors: Bulmash Samuel
Published: May 2007

The paper presents a model which explains the firm's life‐cycle via the agency approach. The application of agency theory to the understanding of the life‐cycle of the firm provides interesting implications for management compensation programs for growth‐inducing policies and for some aspects of mergers. The dynamic model presented here provides a synthesis of different perspectives of the firm and its management.
Risk and prices in separable utility functions
Authors: Engelbrecht‐Wiggans Richard
Published: May 2007

Many decision problems involve more than one attribute. Separable multi‐attribute utility functions are commonly used to model preferences in such situations. We consider the case in which one attribute can be identified as money. The price at which non‐monetary attributes may be substituted by money, the relation of this price to a decision‐maker's wealth, and the implications on attitudes toward risk are examined for additively and multiplicatively separable multi‐attribute utility functions. In particular, it is shown that additive separability, price independent of wealth and monetary risk‐aversion are mutually inconsistent.
An economic analysis of R & D joint ventures
Authors: Bozeman Barry , Link Albert , Zardkoohi Asghar
Published: May 2007

A graphical model of co‐operative R & D activity is presented, from which outcomes of R & D joint ventures are posited. The analysis predicts that R & D spending will increase as a result of co‐operation and that the increment will tend to be in basic research more than applied or development.
Black trade unions and the wage gap in South Africa
Authors: Siebert W. S.
Published: May 2007

This paper puts forward a model of real wage determination for black workers in South Africa. The model is fitted to data for mining and manufacturing for the post‐war period. It is found that since 1980 the rise of black trade unions has been a major factor underlying wage increases in manufacturing. In the 1970s, rising gold prices and reduced foreign labour supplies were favourable for mining labour, and in both industries pass law limitations on mobility are found to have lowered balck wages.
Financial innovation and the boundaries of banking
Authors: Aliber Robert Z.
Published: May 2007

The paper analyzes the interaction of the process of international innovation and the structure of the international banking sector. The advent of new instruments of financing resulted in the growth of disintermediation. This created pressure for the liberalization of banking with the resulting international competition. The banking sector in the USA is fragmented, and offers a widely differing range of services. Innovation has resulted in a change in structure, a reshuffling of participants and a consolidation of financial centers.
Voting rights and shareholder wealth the issuance of limited voting common stock
Authors: Cornett Marcia Millon , Vetsuypens Michael R.
Published: May 2007

This paper investigates the shareholder wealth consequences of the public announcements of the proposed issuance of multiple classes of common stock with disparate voting rights. The evidence suggests that, for our sample of 70 firms which proposed dual‐class recapitalizations over the period 1962–86, the creafion of dual classes of common stock, on average, leads to abnormal stock price increases. The data do not lend support to the hypothesis that the concentration of voting power with incumbent management is detrimental to shareholder interests.
The sequencing of union contract negotiations
Authors: Kovenock Dan , Widdows Kealoha
Published: May 2007

In this paper we explore the determination of the sequencing of wage bargains in an institutional structure consisting of a single firm employing two unions, under two alternative assumptions about the nature of feasible contracts. If contingent contracts are prohibitively costly, we find that the unions prefer to lead in the negotiations process if the labor inputs are substitutes and follow if they are complements, while the firm is indifferent. If contingent contracts are permitted, both unions prefer to lead, while the firm prefers to negotiate first with the weaker union.
Exposure to foreign exchange risk: A multi‐currency extension
Authors: Schnabel Jacques A.
Published: May 2007

The Adler‐Dumas simple regression approach to foreign exchange exposure measurement and hedging is extended to the case of exposure to many currencies.