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18
result(s) for
"Pallerla, Srinivas Reddy"
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Longitudinal monitoring of laboratory markers characterizes hospitalized and ambulatory COVID-19 patients
by
Velavan, Thirumalaisamy P.
,
Kreidenweiss, Andrea
,
Shamsrizi, Parichehr
in
692/53/2421
,
692/53/2422
,
692/53/2423
2021
Early detection of severe forms of COVID-19 is absolutely essential for timely triage of patients. We longitudinally followed-up two well-characterized patient groups, hospitalized moderate to severe (n = 26), and ambulatory mild COVID-19 patients (n = 16) at home quarantine. Human D-dimer, C-reactive protein (CRP), ferritin, cardiac troponin I, interleukin-6 (IL-6) levels were measured on day 1, day 7, day 14 and day 28. All hospitalized patients were SARS-CoV-2 positive on admission, while all ambulatory patients were SARS-CoV-2 positive at recruitment. Hospitalized patients had higher D-dimer, CRP and ferritin, cardiac troponin I and IL-6 levels than ambulatory patients (
p
< 0.001,
p
< 0.001,
p
= 0.016,
p
= 0.035,
p
= 0.002 respectively). Hospitalized patients experienced significant decreases in CRP, ferritin and IL-6 levels from admission to recovery (
p
< 0.001,
p
= 0.025, and
p
= 0.001 respectively). Cardiac troponin I levels were high during the acute phase in both hospitalized and ambulatory patients, indicating a potential myocardial injury. In summary, D-dimer, CRP, ferritin, cardiac troponin I, IL-6 are predictive laboratory markers and can largely determine the clinical course of COVID-19, in particular the prognosis of critically ill COVID-19 patients.
Journal Article
Genetic variants of programmed cell death 1 are associated with HBV infection and liver disease progression
by
Velavan, Thirumalaisamy P.
,
Giang, Dao Phuong
,
Linh, Bui Thuy
in
631/208/1516
,
631/208/2489
,
631/208/727
2021
The inhibitory effects of programmed cell death 1/programmed cell death ligand 1 (PD-1/PD-L1) modulates T-cell depletion. T-cell depletion is one of the key mechanisms of hepatitis B virus (HBV) persistence, in particular liver disease progression and the development of hepatocellular carcinoma (HCC). This case–control study aimed to understand the significance of PD-1 polymorphisms (
PD-1.5 and PD-1.9
) association with HBV infection risk and HBV-induced liver disease progression. Genotyping of
PD-1.5
and
PD-1.9
variants was performed by direct Sanger sequencing in 682 HBV-infected patients including chronic hepatitis (CHB, n = 193), liver cirrhosis (LC, n = 183), hepatocellular carcinoma (HCC, n = 306) and 283 healthy controls (HC). To analyze the association of
PD-1
variants with liver disease progression, a binary logistic regression, adjusted for age and gender, was performed using different genetic models. The
PD-1.9 T
allele and
PD-1.9 TT
genotype are significantly associated with increased risk of LC, HCC, and LC + HCC. The frequencies of
PD-1.5 TT
genotype and
PD-1.5 T
allele are significantly higher in HCC compared to LC patients. The haplotype
CT
(
PD-1.5 C
and
PD-1.9 T
) was significantly associated with increased risk of LC, HCC, and LC + HCC. In addition, the
TC
(
PD-1.5 T
and
PD-1.9 C
) haplotype was associated with the risk of HCC compared to non-HCC. The
PD-1.5 CC, PD-1.9 TT,
genotype, and the
CC
(
PD-1.5 C
and
PD-1.9)
haplotype are associated with unfavorable laboratory parameters in chronic hepatitis B patients.
PD-1.5
and
PD1.9
are useful prognostic predictors for HBV infection risk and liver disease progression.
Journal Article
Antimicrobial resistance preparedness in sub-Saharan African countries
by
Velavan, Thirumalaisamy P.
,
Tembo, John
,
Ippolito, Giuseppe
in
Africa South of the Sahara
,
Animals
,
Antimicrobial agents
2020
Background
Antimicrobial resistance (AMR) is of growing concern globally and AMR status in sub-Saharan Africa (SSA) is undefined due to a lack of real-time data recording, surveillance and regulation. World Health Organization (WHO) Joint External Evaluation (JEE) reports are voluntary, collaborative processes to assess country capacities and preparedness to prevent, detect and rapidly respond to public health risks, including AMR. The data from SSA JEE reports were analysed to gain an overview of how SSA is working towards AMR preparedness and where strengths and weaknesses lie.
Methods
SSA country JEE AMR preparedness scores were analysed. A cumulative mean of all the SSA country AMR preparedness scores was calculated and compared to the overall mean SSA JEE score. AMR preparedness indicators were analysed, and data were weighted by region.
Findings
The mean SSA AMR preparedness score was 53% less than the overall mean SSA JEE score. East Africa had the highest percentage of countries reporting having AMR National Action Plans in place, as well as human and animal pathogen AMR surveillance programmes. Southern Africa reported the highest percentage of countries with training programmes and antimicrobial stewardship.
Conclusions
The low mean AMR preparedness score compared to overall JEE score, along with the majority of countries lacking implemented National Action Plans, suggests that until now AMR has not been a priority for most SSA countries. By identifying regional and One Health strengths, AMR preparedness can be fortified across SSA with a multisectoral approach.
Journal Article
Hepatitis E Virus Infection: Circulation, Molecular Epidemiology, and Impact on Global Health
by
Johne, Reimar
,
Velavan, Thirumalaisamy P.
,
Wenzel, Jürgen J.
in
Animals
,
Epidemics
,
Epidemiology
2020
Infection with hepatitis E virus (HEV) represents the most common source of viral hepatitis globally. Although infecting over 20 million people annually in endemic regions, with major outbreaks described since the 1950s, hepatitis E remains an underestimated disease. This review gives a current view of the global circulation and epidemiology of this emerging virus. The history of HEV, from the first reported enteric non-A non-B hepatitis outbreaks, to the discovery of the viral agent and the molecular characterization of the different human pathogenic genotypes, is discussed. Furthermore, the current state of research regarding the virology of HEV is critically assessed, and the challenges towards prevention and diagnosis, as well as clinical risks of the disease described. Together, these points aim to underline the significant impact of hepatitis E on global health and the need for further in-depth research to better understand the pathophysiology and its role in the complex disease manifestations of HEV infection.
Journal Article
Drug-induced hepatotoxicity and association with slow acetylation variants NAT25 and NAT26 in Cameroonian patients with tuberculosis and HIV co-infection
by
Velavan, Thirumalaisamy P.
,
Kamgno, Joseph
,
Tembo, John
in
Acetylation
,
Acquired immune deficiency syndrome
,
Adult
2024
Background
Human immunodeficiency virus (HIV) and tuberculosis (TB) are major contributors to morbidity and mortality in sub-Saharan Africa including Cameroon. Pharmacogenetic variants could serve as predictors of drug-induced hepatotoxicity (DIH), in patients with TB co-infected with HIV. We evaluated the occurrence of DIH and pharmacogenetic variants in Cameroonian patients.
Methods
Treatment-naïve patients with HIV, TB or TB/HIV co-infection were recruited at three hospitals in Cameroon, between September 2018 and November 2019. Appropriate treatment was initiated, and patients followed up for 12 weeks to assess DIH. Pharmacogenetic variants were assessed by allele discrimination TaqMan SNP assays.
Results
Of the 141 treatment naïve patients, the overall incidence of DIH was 38% (53/141). The highest incidence of DIH, 52% (32/61), was observed among HIV patients. Of 32 pharmacogenetic variants, the slow acetylation variants
NAT2
*5 was associated with a decreased risk of DIH (OR: 0.4; 95%CI: 0.17–0.96;
p
= 0.038), while
NAT2
*6 was found to be associated with an increased risk of DIH (OR: 4.2; 95%CI: 1.1–15.2;
p
= 0.017) among patients treated for TB. Up to 15 SNPs differed in ≥ 5% of allele frequencies among African populations, while 25 SNPs differed in ≥ 5% of the allele frequencies among non-African populations, respectively.
Conclusions
DIH is an important clinical problem in African patients with TB and HIV. The
NAT2
*5 and
NAT2
*6 variants were found to be associated with DIH in the Cameroonian population. Prior screening for the slow acetylation variants
NAT2*5
and
NAT2*6
may prevent DIH in TB and HIV-coinfected patients.
Journal Article
Molecular surveillance and temporal monitoring of malaria parasites in focal Vietnamese provinces
by
Quyet, Do
,
Velavan, Thirumalaisamy P.
,
Son, Ho Anh
in
Alleles
,
Analytical methods
,
Biomedical and Life Sciences
2020
Background
While the World Health Organization (WHO) Southeast Asia region has the second highest incidence of malaria worldwide, malaria in Vietnam is focal to few provinces, where delayed parasite clearance to anti-malarial drugs is documented. This study aims to understand
Plasmodium
species distribution and the genetic diversity of
msp1
and
msp2
of parasite populations using molecular tools.
Methods
A total of 222 clinical isolates from individuals with uncomplicated malaria were subjected to
Plasmodium
species identification by nested real-time PCR. 166 isolates positive for
Plasmodium falciparum
mono infections were further genotyped for
msp1
(MAD20, K1, and RO33), and
msp2
allelic families (3D7 and FC27). Amplicons were resolved through capillary electrophoresis in the QIAxcel Advanced system.
Results
Mono-infections were high and with 75%
P. falciparum
, 14%
Plasmodium vivax
and 9%
P. falciparum/P. vivax
co-infections, with less than 1%
Plasmodium malariae
identified. For
msp1
, MAD20 was the most prevalent (99%), followed by K1 (46%) allelic family, with no sample testing positive for RO33 (0%). For
msp2
, 3D7 allelic family was predominant (97%), followed by FC27 (10%). The multiplicity of infection of
msp1
and
msp2
was 2.6 and 1.1, respectively, and the mean overall multiplicity of infection was 3.7, with the total number of alleles ranging from 1 to 7.
Conclusions
Given the increasing importance of antimalarial drugs in the region, the genetic diversity of
P. falciparum msp1
and
msp2
should be regularly monitored with respect to treatment outcomes and/or efficacy studies in regions, where there are ongoing changes in the malaria epidemiology.
Journal Article
Diagnosis of pathogens causing bacterial meningitis using Nanopore sequencing in a resource-limited setting
by
Velavan, Thirumalaisamy P.
,
Boutin, Sébastien
,
Quyen, Dao Thanh
in
16S rRNA
,
Analysis
,
Antibiotics
2022
Aim
The aim of the present study is to compare the performance of 16S rRNA Nanopore sequencing and conventional culture in detecting infectious pathogens in patients with suspected meningitis in a resource-limited setting without extensive bioinformatics expertise.
Methods
DNA was isolated from the cerebrospinal fluid (CSF) of 30 patients with suspected bacterial meningitis. The isolated DNA was subjected to 16S sequencing using MinION™. The data were analysed in real time via the EPI2ME cloud platform. The Nanopore sequencing was done in parallel to routine microbiological diagnostics.
Results
Nanopore sequencing detected bacterial pathogens to species level in 13 of 30 (43%) samples. CSF culture showed 40% (12/30) positivity. In 21 of 30 patients (70%) with suspected bacterial meningitis, both methods yielded concordant results. About nine of 30 samples showed discordant results, of these five were false positive and four were false negative. In five of the culture negative results, nanopore sequencing was able to detect pathogen genome, due to the higher sensitivity of the molecular diagnostics. In two other samples, the CSF culture revealed Cryptococcus neoformans and Streptococcus pneumoniae, which were not detected by Nanopore sequencing. Overall, using both the cultures and 16S Nanopore sequencing, positivity rate increased from 40% (12/30) to 57% (17/30).
Conclusion
Next-generation sequencing could detect pathogens within six hours and could become an important tool for both pathogen screening and surveillance in low- and middle-income countries (LMICs) that do not have direct access to extensive bioinformatics expertise.
Journal Article
Custom gene expression panel for evaluation of potential molecular markers in hepatocellular carcinoma
by
Velavan, Thirumalaisamy P.
,
Giang, Dao Phuong
,
Toan, Nguyen Linh
in
alpha-Fetoproteins
,
Architects
,
Biological markers
2022
Background
Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related mortality worldwide. It is a highly heterogeneous disease with poor prognosis and limited treatment options, which highlights the need for reliable biomarkers. This study aims to explore molecular markers that allow stratification of HCC and may lead to better prognosis and treatment prediction.
Materials and methods
We studied 20 candidate genes (HCC hub genes, potential drug target genes, predominant somatic mutant genes) retrieved from literature and public databases with potential to be used as the molecular markers. We analysed expression of the genes by RT-qPCR in 30 HCC tumour and adjacent non-tumour paired samples from Vietnamese patients. Fold changes in expression were then determined using the 2
−∆∆CT
method, and unsupervised hierarchical clustering was generated using Cluster v3.0 software.
Results
Clustering of expression data revealed two subtypes of tumours (proliferative and normal-like) and four clusters for genes. The expression profiles of the genes
TOP2A, CDK1, BIRC5, GPC3, IGF2,
and
AFP
were strongly correlated. Proliferative tumours were characterized by high expression of the c
-MET, ARID1A, CTNNB1, RAF1, LGR5
, and
GLUL1
genes.
TOP2A, CDK1
, and
BIRC5
HCC hub genes were highly expressed (> twofold) in 90% (27/30), 83% (25/30), and 83% (24/30) in the tissue samples, respectively. Among the drug target genes, high expression was observed in the
GPC3, IGF2
and
c-MET
genes in 77% (23/30), 63% (19/30), and 37% (11/30), respectively. The somatic mutant Wnt/ß-catenin genes (
CTNNB1, GLUL and LGR5
) and
TERT
were highly expressed in 40% and 33% of HCCs, respectively. Among the HCC marker genes, a higher percentage of tumours showed
GPC3
expression compared to
AFP
expression [73% (23/30) vs. 43% (13/30)].
Conclusion
The custom panel and molecular markers from this study may be useful for diagnosis, prognosis, biomarker-guided clinical trial design, and prediction of treatment outcomes.
Journal Article
Predominance of HBV Genotype B and HDV Genotype 1 in Vietnamese Patients with Chronic Hepatitis
by
Velavan, Thirumalaisamy P.
,
Wedemeyer, Heiner
,
Pallerla, Srinivas Reddy
in
Alanine
,
Alanine transaminase
,
Annealing
2021
Hepatitis delta virus (HDV) coinfection will additionally aggravate the hepatitis B virus (HBV) burden in the coming decades, with an increase in HBV-related liver diseases. Between 2018 and 2019, a total of 205 HBV patients clinically characterized as chronic hepatitis B (CHB; n = 115), liver cirrhosis (LC; n = 21), and hepatocellular carcinoma (HCC; n = 69) were recruited. HBV surface antigen (HBsAg), antibodies against surface antigens (anti-HBs), and core antigens (anti-HBc) were determined by ELISA. The presence of hepatitis B viral DNA and hepatitis delta RNA was determined. Distinct HBV and HDV genotypes were phylogenetically reconstructed and vaccine escape mutations in the “a” determinant region of HBV were elucidated. All HBV patients were HbsAg positive, with 99% (n = 204) and 7% (n = 15) of them being positive for anti-HBc and anti-HBs, respectively. Anti-HBs positivity was higher among HCC (15%; n = 9) compared to CHB patients. The HBV-B genotype was predominant (65%; n = 134), followed by HBV-C (31%; n = 64), HBV-D, and HBV-G (3%; n = 7). HCC was observed frequently among young individuals with HBV-C genotypes. A low frequency (2%; n = 4) of vaccine escape mutations was observed. HBV-HDV coinfection was observed in 16% (n = 33) of patients with the predominant occurrence of the HDV-1 genotype. A significant association of genotypes with alanine aminotransferase (ALT) and aspartate aminotransferase (AST) enzyme levels was observed in HBV monoinfections. The prevalence of the HDV-1 genotype is high in Vietnam. No correlation was observed between HDV-HBV coinfections and disease progression when compared to HBV monoinfections.
Journal Article