Pham Trong - Academia.edu (original) (raw)

Papers by Pham Trong

Research paper thumbnail of Norovirus and Sapovirus Infections among Children with Acute Gastroenteritis in Ho Chi Minh City during 2005-2006

Journal of Tropical Pediatrics, 2007

A molecular epidemiological study on common diarrheal viruses was conducted in a children&amp... more A molecular epidemiological study on common diarrheal viruses was conducted in a children's hospital in Ho Chi Minh City between December 2005 and November 2006. Fecal samples were collected from 502 pediatric patients with acute gastroenteritis, and were screened for the presence of norovirus (NoV) and sapovirus (SaV). NoVs GII and SaVs were detected in 6.4% and 1.2% specimens, respectively, while there was no NoV GI found among studied samples. NoVs could be identified through the year, except in April and July, with the peak of detection rate (62.5%) during the rainy season. Conversely, four out of six (66.7%) of the SaV strains were identified during the dry season. Patients aged between 6 and 23 months were found to be more infected by NoVs. The overall mean severity score of norovirus-positive patients was 9.8 +/- 3.6, and no significant difference of severity scores among patients belonged to different age groups, gender and place of living. The results of phylogenetic analysis showed the diversity of caliciviruses circulating in the area, and various types of recombination were identified among NoVs and SaVs detected. These results provide important information on calicivirus infections among Vietnamese children.

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Research paper thumbnail of A Hausdorff-like moment problem and the inversion of the Laplace transform

Mathematische Nachrichten, 2006

We consider the problem of finding u ∈ L2(I ), I = (0, 1), satisfying∫Iu (x )x dx = μk,∫Iu (x )x ... more We consider the problem of finding u ∈ L2(I ), I = (0, 1), satisfying∫Iu (x )x dx = μk,∫Iu (x )x dx = μk,where k = 0, 1, 2, …, (αk) is a sequence of distinct real numbers greater than –1/2, and μ = (μkl) is a given bounded sequence of real numbers. This is an ill-posed problem. We shall regularize the problem by finite moments and then, apply the result to reconstruct a function on (0, +∞) from a sequence of values of its Laplace transforms. Error estimates are given. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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Research paper thumbnail of Identification of human astrovirus infections among children with acute gastroenteritis in the Southern Part of Vietnam during 2005–2006

Journal of Medical Virology, 2008

A molecular epidemiological study on common diarrheal viruses was conducted in a children's hospi... more A molecular epidemiological study on common diarrheal viruses was conducted in a children's hospital in Ho Chi Minh City between December 2005 and November 2006. Fecal samples were collected from 502 pediatric patients with acute gastroenteritis, and were screened for eight types of viral agents. Human astroviruses (HAstVs), which were detected with a prevalence of 13.9%, became the second most frequent viral enteropathogen. Although detected in both dry and rainy seasons, the majority (92.8%) of HAstVs in this study were found in the rainy season. Patients aged between 6 and 23 months were found to be more infected from astrovirus when compared to other age groups. The ratio between boys and girls was 2.3:1. The overall mean severity score of astrovirus positive patients was 11.8 ± 2.45. The mean severity score of the inpatients was statistically higher than that of the outpatients; however, there was no difference in severity scores between the age groups observed. The clinical manifestations of astrovirus infections among the Vietnamese children were diarrhea, vomiting, fever, coughing, and coryza. All of the detected astroviruses belonged to genotype 1. The phylogenetic tree clearly indicated that HAstVs-1 worldwide could be classified into four different lineages, in which, Vietnamese astroviruses and other recently isolated strains from other countries clustered into the distinct lineage, 1d. These results provide important information on astrovirus infections among Vietnamese children. J. Med. Virol. 80:298–305, 2008. © 2007 Wiley-Liss, Inc.

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Research paper thumbnail of Unique secondary chromosomal abnormalities are frequently found in the chronic phase of chronic myeloid leukemia in southern Vietnam

Cancer Genetics and Cytogenetics, 2006

During the Vietnam War, southern Vietnam was exposed to a large amount of dioxin, a strong human ... more During the Vietnam War, southern Vietnam was exposed to a large amount of dioxin, a strong human carcinogen. Although we have observed much shorter survival in southern Vietnamese chronic myeloid leukemia (CML) patients, the cause remains to be clarified. Here, we report cytogenetic and molecular findings for 47 CML patients. Cytogenetically, the Philadelphia (Ph) chromosome was found in 44 patients (93.6%); of the remaining 3 patients with Ph-negative CML, 2 exhibited BCR/ABL transcripts but no BCR/ABL FISH fusion signals, suggesting the existence of two clones, with and without the BCR/ABL fusion gene. Surprisingly, in 17 patients (36.2%) (4 at diagnosis, 11 during chronic phase, and 2 in accelerated phase), we found several unique secondary chromosome abnormalities including trisomy 13, partial trisomy 13, and abnormalities of 1p, 3p, 6p, 7p, 10p, and 11p, which are different from the so-called additional chromosome abnormalities (extra Ph, +8, i(17q), +19, and +21) observed in blastic phase CML. FISH analysis revealed the Ph translocation with der(9) deletion in 11 patients (23.4%). Of these, 2 had two clones, with and without der(9) deletion, suggesting that der(9) deletion would occur in a subset of patients during disease progression. These observations point to preexisting genetic instability that induces various secondary chromosome abnormalities and multiple clones, resulting in shorter survival.

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Research paper thumbnail of Use of sequence analysis of the VP4 gene to classify recent Vietnamese rotavirus isolates

Clinical Microbiology and Infection, 2008

Twenty-eight strains of P(8), four of P(4) and one of P(19) rotavirus, isolated in Ho Chi Minh Ci... more Twenty-eight strains of P(8), four of P(4) and one of P(19) rotavirus, isolated in Ho Chi Minh City, Vietnam, during 2002–2003, were investigated by sequence analysis of the VP4 gene. Seven of the 28 P(8) rotavirus VP4 sequences clustered in the P(8)-3 lineage, or the rare, so-called OP354-like lineage. Amino-acid sequence comparison revealed that Vietnamese P(8)-3 rotaviruses were generally very similar to Malawian strains, including the prototype OP354 strain. The numerical severity scores of diarrhoeal disease caused by the Vietnamese P(8)-3 rotaviruses were statistically higher than those of diarrhoeal disease caused by rotaviruses in the more common P(8)-2 lineage. Sequence and phylogenetic analysis of the VP4 gene of a Vietnamese G9P(19) rotavirus isolate showed a high degree of homology with the cognate genes of other human and porcine rotaviruses, including the prototype 4F strain.

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Research paper thumbnail of Norovirus and Sapovirus Infections among Children with Acute Gastroenteritis in Ho Chi Minh City during 2005-2006

Journal of Tropical Pediatrics, 2007

A molecular epidemiological study on common diarrheal viruses was conducted in a children&amp... more A molecular epidemiological study on common diarrheal viruses was conducted in a children's hospital in Ho Chi Minh City between December 2005 and November 2006. Fecal samples were collected from 502 pediatric patients with acute gastroenteritis, and were screened for the presence of norovirus (NoV) and sapovirus (SaV). NoVs GII and SaVs were detected in 6.4% and 1.2% specimens, respectively, while there was no NoV GI found among studied samples. NoVs could be identified through the year, except in April and July, with the peak of detection rate (62.5%) during the rainy season. Conversely, four out of six (66.7%) of the SaV strains were identified during the dry season. Patients aged between 6 and 23 months were found to be more infected by NoVs. The overall mean severity score of norovirus-positive patients was 9.8 +/- 3.6, and no significant difference of severity scores among patients belonged to different age groups, gender and place of living. The results of phylogenetic analysis showed the diversity of caliciviruses circulating in the area, and various types of recombination were identified among NoVs and SaVs detected. These results provide important information on calicivirus infections among Vietnamese children.

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Research paper thumbnail of A Hausdorff-like moment problem and the inversion of the Laplace transform

Mathematische Nachrichten, 2006

We consider the problem of finding u ∈ L2(I ), I = (0, 1), satisfying∫Iu (x )x dx = μk,∫Iu (x )x ... more We consider the problem of finding u ∈ L2(I ), I = (0, 1), satisfying∫Iu (x )x dx = μk,∫Iu (x )x dx = μk,where k = 0, 1, 2, …, (αk) is a sequence of distinct real numbers greater than –1/2, and μ = (μkl) is a given bounded sequence of real numbers. This is an ill-posed problem. We shall regularize the problem by finite moments and then, apply the result to reconstruct a function on (0, +∞) from a sequence of values of its Laplace transforms. Error estimates are given. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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Research paper thumbnail of Identification of human astrovirus infections among children with acute gastroenteritis in the Southern Part of Vietnam during 2005–2006

Journal of Medical Virology, 2008

A molecular epidemiological study on common diarrheal viruses was conducted in a children's hospi... more A molecular epidemiological study on common diarrheal viruses was conducted in a children's hospital in Ho Chi Minh City between December 2005 and November 2006. Fecal samples were collected from 502 pediatric patients with acute gastroenteritis, and were screened for eight types of viral agents. Human astroviruses (HAstVs), which were detected with a prevalence of 13.9%, became the second most frequent viral enteropathogen. Although detected in both dry and rainy seasons, the majority (92.8%) of HAstVs in this study were found in the rainy season. Patients aged between 6 and 23 months were found to be more infected from astrovirus when compared to other age groups. The ratio between boys and girls was 2.3:1. The overall mean severity score of astrovirus positive patients was 11.8 ± 2.45. The mean severity score of the inpatients was statistically higher than that of the outpatients; however, there was no difference in severity scores between the age groups observed. The clinical manifestations of astrovirus infections among the Vietnamese children were diarrhea, vomiting, fever, coughing, and coryza. All of the detected astroviruses belonged to genotype 1. The phylogenetic tree clearly indicated that HAstVs-1 worldwide could be classified into four different lineages, in which, Vietnamese astroviruses and other recently isolated strains from other countries clustered into the distinct lineage, 1d. These results provide important information on astrovirus infections among Vietnamese children. J. Med. Virol. 80:298–305, 2008. © 2007 Wiley-Liss, Inc.

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Research paper thumbnail of Unique secondary chromosomal abnormalities are frequently found in the chronic phase of chronic myeloid leukemia in southern Vietnam

Cancer Genetics and Cytogenetics, 2006

During the Vietnam War, southern Vietnam was exposed to a large amount of dioxin, a strong human ... more During the Vietnam War, southern Vietnam was exposed to a large amount of dioxin, a strong human carcinogen. Although we have observed much shorter survival in southern Vietnamese chronic myeloid leukemia (CML) patients, the cause remains to be clarified. Here, we report cytogenetic and molecular findings for 47 CML patients. Cytogenetically, the Philadelphia (Ph) chromosome was found in 44 patients (93.6%); of the remaining 3 patients with Ph-negative CML, 2 exhibited BCR/ABL transcripts but no BCR/ABL FISH fusion signals, suggesting the existence of two clones, with and without the BCR/ABL fusion gene. Surprisingly, in 17 patients (36.2%) (4 at diagnosis, 11 during chronic phase, and 2 in accelerated phase), we found several unique secondary chromosome abnormalities including trisomy 13, partial trisomy 13, and abnormalities of 1p, 3p, 6p, 7p, 10p, and 11p, which are different from the so-called additional chromosome abnormalities (extra Ph, +8, i(17q), +19, and +21) observed in blastic phase CML. FISH analysis revealed the Ph translocation with der(9) deletion in 11 patients (23.4%). Of these, 2 had two clones, with and without der(9) deletion, suggesting that der(9) deletion would occur in a subset of patients during disease progression. These observations point to preexisting genetic instability that induces various secondary chromosome abnormalities and multiple clones, resulting in shorter survival.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Use of sequence analysis of the VP4 gene to classify recent Vietnamese rotavirus isolates

Clinical Microbiology and Infection, 2008

Twenty-eight strains of P(8), four of P(4) and one of P(19) rotavirus, isolated in Ho Chi Minh Ci... more Twenty-eight strains of P(8), four of P(4) and one of P(19) rotavirus, isolated in Ho Chi Minh City, Vietnam, during 2002–2003, were investigated by sequence analysis of the VP4 gene. Seven of the 28 P(8) rotavirus VP4 sequences clustered in the P(8)-3 lineage, or the rare, so-called OP354-like lineage. Amino-acid sequence comparison revealed that Vietnamese P(8)-3 rotaviruses were generally very similar to Malawian strains, including the prototype OP354 strain. The numerical severity scores of diarrhoeal disease caused by the Vietnamese P(8)-3 rotaviruses were statistically higher than those of diarrhoeal disease caused by rotaviruses in the more common P(8)-2 lineage. Sequence and phylogenetic analysis of the VP4 gene of a Vietnamese G9P(19) rotavirus isolate showed a high degree of homology with the cognate genes of other human and porcine rotaviruses, including the prototype 4F strain.

Bookmarks Related papers MentionsView impact