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Biomedical subjects

Katja C Wolthers

Publications and source records attributed to Katja C Wolthers.

7 recordsLinked to original sources

Viral dynamics after starting first-line HAART in HIV-1-infected children.

BACKGROUND: After starting HAART, the plasma HIV-1 RNA (pVL) declines rapidly to undetectable levels in most treated adults and children. The viral dynamics in children are assumed to differ from those in adults. Therefore viral decay and time to reach a pVL of < 400 copies/ml during the first weeks after starting HAART were studied in a cohort of HIV-1-infected children. METHODS: Viral decay expressed as half-life and time to reach a pVL of < 400 copies/ml in 39 HIV-1-infected children starting HAART were calculated and correlated with age, pretreatment with antiretroviral mono- or duo-therapy, and baseline pVL. RESULTS: Baseline pVL correlated with age (r, -0.41; P = 0.01). Median half-life of the virus was 2.1 days (interquartile range, 1.8-3.0 days). No correlation was found between the half-life of the virus and the baseline pVL at the start of treatment, antiretroviral pretreatment or age. Eight children did not reach a pVL of < 400 copies/ml with the first allocated medication regimen. These children were significantly younger than those in whom HIV was successfully suppressed (P = 0.009). The remaining 31 children reached a pVL of < 400 copies/ml in a median of 8.1 weeks after the start of therapy; time to reach a pVL of < 400 copies/ml was only correlated with baseline pVL. CONCLUSIONS: These results suggest that pVL at baseline correlated with age. HAART was able to suppress pVL below the lower limit of detection in children with a viral decay rate of 2.1 days, similar to adults and irrespective of baseline pVL.

Age Factors↗

Fourth human parechovirus serotype.

We identified a novel human parechovirus (HPeV) type (K251176-02) from a neonate with fever. Analysis of the complete genome showed K251176-02 to be a new HPeV genotype. Since K251176-02 could not be neutralized with antibodies against known HPeV serotypes 1-3, it should be classified as a fourth HPeV serotype.

Base Sequence↗

Identification of a new human coronavirus.

Three human coronaviruses are known to exist: human coronavirus 229E (HCoV-229E), HCoV-OC43 and severe acute respiratory syndrome (SARS)-associated coronavirus (SARS-CoV). Here we report the identification of a fourth human coronavirus, HCoV-NL63, using a new method of virus discovery. The virus was isolated from a 7-month-old child suffering from bronchiolitis and conjunctivitis. The complete genome sequence indicates that this virus is not a recombinant, but rather a new group 1 coronavirus. The in vitro host cell range of HCoV-NL63 is notable because it replicates on tertiary monkey kidney cells and the monkey kidney LLC-MK2 cell line. The viral genome contains distinctive features, including a unique N-terminal fragment within the spike protein. Screening of clinical specimens from individuals suffering from respiratory illness identified seven additional HCoV-NL63-infected individuals, indicating that the virus was widely spread within the human population.

Adult↗

Regulatory regions in the rat lactase-phlorizin hydrolase gene that control cell-specific expression.

OBJECTIVES: Lactase-phlorizin hydrolase (LPH) is an enterocyte-specific gene whose expression has been well-characterized, not only developmentally but also along the crypt-villus axis and along the length of the small bowel. Previous studies from the authors' laboratory have demonstrated that 2 kb of the 5'-flanking region of the rat LPH gene control the correct tissue, cell, and crypt-villus expression in transgenic animals. METHODS: To examine further the regulation conferred by this region, protein-DNA interactions were studied using DNase I footprint analyses in LPH-expressing and nonexpressing cell lines. Functional delineation of this 5'-flanking sequence was performed using deletion analysis in transient transfection assays. RESULTS: Studies revealed a generally positive activity between -74 and -37 bp, a cell-specific negative region between -210 and -95 bp, and additional elements further toward the 5'-terminus that conferred a highly cell-specific response in reporter activity. Computer analysis of distal regions encompassing identified footprints revealed potential binding sites for various intestinal transcription factors. Co-transfection and electromobility shift assay experiments indicated binding of HNF3beta at three sites relevant to LPH expression. CONCLUSIONS: The data demonstrate that the cell specificity of LPH gene expression depends upon both positive and negative interactions among elements in the first 2 kb of the LPH 5'-flanking region.

Animals↗

A case of Mycoplasma hominis meningo-encephalitis in a full-term infant: rapid recovery after start of treatment with ciprofloxacin.

UNLABELLED: The role of Mycoplasma hominisas a causative agent for neonatal sepsis and meningitis is still unclear. Meningitis secondary to M. hominisis well-described in the literature; however, M. hominiscan also be isolated from cerebrospinal fluid (CSF) obtained from infants without signs of meningitis. We present a case of a full-term infant with meningo-encephalitis with seizures, epileptic activity on the EEG, inflammation of brain tissue on a CT scan, and cloudy CSF containing elevated cell counts, decreased glucose levels and elevated protein levels. M. hominiswas identified from the CSF by culture and by polymerase chain reaction (PCR) as the only possible causative agent. Furthermore, while empiric antibiotic and antiviral treatment for neonatal sepsis had failed, the meningo-encephalitis promptly responded upon antibiotic treatment with ciprofloxacin (20 mg/kg per day i.v.), to which M. hominisis susceptible. CONCLUSION: A meningo-encephalitis developed due to infection with M. hominisin a full-term infant, from which he recovered rapidly after start of treatment with ciprofloxacin.

Anti-Infective Agents↗

Absolute level of Epstein-Barr virus DNA in human immunodeficiency virus type 1 infection is not predictive of AIDS-related non-Hodgkin lymphoma.

To study whether Epstein-Barr virus (EBV) load can be used to predict the occurrence of acquired immunodeficiency syndrome-related non-Hodgkin lymphoma (AIDS-NHL), we determined EBV load longitudinally for individuals infected with human immunodeficiency virus type 1. EBV load in peripheral blood mononuclear cells (PBMC) was high and displayed considerable fluctuations over time, indicating that absolute EBV load in PBMC is not predictive of the development of AIDS-NHL. EBV DNA was also detectable in serum at some time points but at a lower level.

DNA, Viral↗