Browse Health


Education ?

Medical School Score
Western University of Health Sciences (1992)

Awards & Distinctions ?

Compassionate Doctor Recognition (2014)
American Board of Internal Medicine

Affiliations ?

Dr. Eichinger is affiliated with 7 hospitals.

Hospital Affiliations



  • Citrus Valley Medical Center - Queen of the Valley Campus
    1115 S Sunset Ave, West Covina, CA 91790
    Top 25%
  • Foothill Presbyterian Hospital
    250 S Grand Ave, Glendora, CA 91741
    Top 25%
  • San Dimas Community Hospital
    1350 W Covina Blvd, San Dimas, CA 91773
    Top 50%
  • Greater El Monte Community Hospital
    1701 Santa Anita Ave, South El Monte, CA 91733
    Top 50%
  • Citrus Valley Medical Center - Inter-Community Campus
    210 W San Bernardino Rd, Covina, CA 91723
    Top 50%
  • Monterey Park Hospital
    900 S Atlantic Blvd, Monterey Park, CA 91754
  • Citrus Valley Med Center
  • Publications & Research

    Dr. Eichinger has contributed to 8 publications.
    Title Identification of Developmentally Regulated Genes in Entamoeba Histolytica: Insights into Mechanisms of Stage Conversion in a Protozoan Parasite.
    Date December 2007
    Journal Cellular Microbiology

    Developmental switching between life-cycle stages is a common feature among many pathogenic organisms. The protozoan parasite Entamoeba histolytica converts between cysts (essential for disease transmission) and trophozoites (responsible for tissue invasion). Identification of genes involved in the developmental pathway has been severely hindered by the inability to generate E. histolytica cysts in vitro. Using parasite strains derived from recent human infections and whole-genome transcriptional profiling, we determined that 1439 genes (approximately 15% of annotated genes) were potentially developmentally regulated. Genes enriched in cysts (672 in total) included cysteine proteinases and transmembrane protein kinases, which may be involved in signal transduction. Genes enriched in trophozoites (767 in total) included genes typically thought of as important in tissue invasion by trophozoites, including the Gal/GalNAc lectin light subunit and cysteine protease 1. Putative regulators of differentiation including possible G-protein coupled receptors, signal transduction proteins and transcription factors were identified. A number of E. histolytica stage-specific genes were also developmentally regulated in the reptilian parasite E. invadens, indicating that they likely have conserved functions in Entamoeba development. These advances lay the groundwork for dissection of the molecular signals that initiate stage conversion and development of novel diagnostic and therapeutic measures targeting E. histolytica cysts.

    Title Trichostatin A Effects on Gene Expression in the Protozoan Parasite Entamoeba Histolytica.
    Date August 2007
    Journal Bmc Genomics

    BACKGROUND: Histone modification regulates chromatin structure and influences gene expression associated with diverse biological functions including cellular differentiation, cancer, maintenance of genome architecture, and pathogen virulence. In Entamoeba, a deep-branching eukaryote, short chain fatty acids (SCFA) affect histone acetylation and parasite development. Additionally, a number of active histone modifying enzymes have been identified in the parasite genome. However, the overall extent of gene regulation tied to histone acetylation is not known. RESULTS: In order to identify the genome-wide effects of histone acetylation in regulating E. histolytica gene expression, we used whole-genome expression profiling of parasites treated with SCFA and Trichostatin A (TSA). Despite significant changes in histone acetylation patterns, exposure of parasites to SCFA resulted in minimal transcriptional changes (11 out of 9,435 genes transcriptionally regulated). In contrast, exposure to TSA, a more specific inhibitor of histone deacetylases, significantly affected transcription of 163 genes (122 genes upregulated and 41 genes downregulated). Genes modulated by TSA were not regulated by treatment with 5-Azacytidine, an inhibitor of DNA-methyltransferase, indicating that in E. histolytica the crosstalk between DNA methylation and histone modification is not substantial. However, the set of genes regulated by TSA overlapped substantially with genes regulated during parasite development: 73/122 genes upregulated by TSA exposure were upregulated in E. histolytica cysts (p-value = 6 x 10(-53)) and 15/41 genes downregulated by TSA exposure were downregulated in E. histolytica cysts (p-value = 3 x 10(-7)). CONCLUSION: This work represents the first genome-wide analysis of histone acetylation and its effects on gene expression in E. histolytica. The data indicate that SCFAs, despite their ability to influence histone acetylation, have minimal effects on gene transcription in cultured parasites. In contrast, the effect of TSA on E. histolytica gene expression is more substantial and includes genes involved in the encystation pathway. These observations will allow further dissection of the effects of histone acetylation and the genetic pathways regulating stage conversion in this pathogenic parasite.

    Title In-frame Linker Insertion Mutagenesis of Yeast Transposon Ty1: Phenotypic Analysis.
    Date March 1994
    Journal Gene

    A plasmid bearing a transpositionally functional GAL1::Ty1 fusion was mutagenized by insertion of four or five codons semirandomly throughout the plasmid. This collection of mutant plasmids was introduced into yeast cells and studied with regard to the properties of the mutant Ty1-encoded proteins and the transposition phenotypes observed. All of the transposition-inactivating mutations were previously found to be recessive with the exception of a single mutation in TYA. In this mutant, TYA protein of normal abundance is produced, but the virus-like particles containing this protein are unstable and have aberrant behavior. The effects of mutations in noncoding regions, as well as the capsid protein coding region TYA, and the regions encoding the protease, integrase and reverse transcriptase proteins are described. Effects on gene expression, types of proteins produced, proteolysis of precursor proteins, virus-like particle structure, and biochemical activities of the encoded proteins are summarized. In addition, we show that one of the mutations in the 3' LTR represents a new nonessential site into which foreign marker DNA can be inserted without compromising transposition.

    Title Doubling Ty1 Element Copy Number in Saccharomyces Cerevisiae: Host Genome Stability and Phenotypic Effects.
    Date March 1992
    Journal Genetics

    Haploid yeast strains bearing approximately double the normal number of Ty1 elements have been constructed using marked GAL/Ty1 fusion plasmids. The strains maintain their high transposon copy number and overall genome structure in the absence of selection. The strains bearing extra Ty1 copies are surprisingly similar phenotypically to the parental strain. The results suggest that the limit to transposon copy number, if any, has not been reached. When these strains are crossed by wild-type strains (i.e., bearing the normal complement of Ty1 elements) or by strains of opposite mating type also bearing excess Ty1 elements, normal to very slightly reduced spore viability is observed, indicating that increasing the extent of transposon homology scattered around the genome does not result in significant increases in frequency of ectopic reciprocal recombination. The results suggest that yeast cells have evolved mechanisms for coping with excess transposon copies in the genome.

    Title A Specific Terminal Structure is Required for Ty1 Transposition.
    Date June 1990
    Journal Genes & Development

    Yeast retrotransposon Ty1 directs the synthesis of virus-like particles (VLPs) consisting of Ty1-encoded proteins, RNA, and reverse transcripts. Ty1 reverse transcripts, tagged with a selectable marker and found within VLPs, are capable of transposing into naked target DNA in vitro. Cassettes consisting of a Ty long terminal repeat (LTR), or delta, marked with supF, and flanked by appropriate restriction sites were constructed. These artificial substrates, whose termini resemble those of linear, full-length Ty1 reverse transcripts, can be coincubated with VLPs (containing unmarked reverse transcripts), resulting in the very efficient integration of the artificial substrate. The results suggest that Ty DNA is limiting for transposition in vivo, suggesting that inefficient reverse transcription regulates Ty1 transposition. Analysis of the transposition of these model substrates, which resemble in vivo Ty1 transposition intermediates or differ from them in subtle ways, shows that Ty transposition proceeds by the linkage of the 3' hydroxyl residue of the reverse transcript to target DNA.

    Title The Dna Intermediate in Yeast Ty1 Element Transposition Copurifies with Virus-like Particles: Cell-free Ty1 Transposition.
    Date October 1988
    Journal Cell

    Yeast Ty1 elements are retrotransposons that transpose via an RNA intermediate found in a virus-like particle (Ty-VLP). A Ty-encoded reverse transcriptase activity found inside the particles is capable of giving rise to full-length reverse transcripts. The predominant form of these reverse transcripts is a full-length linear duplex DNA. We have developed a cell-free system for transposition of Ty1 DNA molecules into a bacteriophage lambda target. Purified Ty-VLPs and target DNA are the only macromolecular components required for the transposition reaction. A TYB-encoded protein, p90-TYB, contains amino acid sequences that are similar to those of retroviral integrase proteins. Mutations in the integrase coding region abolish transposition both in vivo and in vitro.

    Title Circumsporozoite Protein of Plasmodium Berghei: Gene Cloning and Identification of the Immunodominant Epitopes.
    Date February 1987
    Journal Molecular and Cellular Biology

    The gene encoding the circumsporozoite (CS) protein of the rodent malaria parasite Plasmodium berghei was cloned and characterized. A cDNA library made from P. berghei sporozoite RNA was screened with a monoclonal antibody for expression of CS protein epitopes. The resulting cDNA clone was used to isolate the CS protein gene from a lambda library containing parasite blood-stage DNA. The CS protein gene contains a central region encoding two types of tandemly repeated amino acid units, flanked by nonrepeated regions encoding amino- and carboxy-terminal signal and anchorlike sequences, respectively. One of the central repeated amino acid unit types contains the immunodominant epitopes.

    Title Analysis of Commercial Entamoeba Histolytica Elisa Kits for the Detection of Entamoeba Invadens in Reptiles.
    Journal Journal of Zoo and Wildlife Medicine : Official Publication of the American Association of Zoo Veterinarians

    Entamoeba invadens is pathogenic in multiple reptile species and has caused severe outbreaks in zoos and other facilities worldwide. Infections can be difficult to diagnose and to differentiate from other reptilian Entamoeba species. The goal of this study was to determine if kits developed to identify the human pathogen Entamoeba histolytica could be used to detect E. invadens in reptile species at the Maryland Zoo. The E. histolytica II antigen enzyme-linked immunosorbent assay and the ProSpecT E. histolytica microplate assay did not react with cultured E. invadens controls or with fecal samples from multiple reptiles, demonstrating the need for a sensitive and specific test for E. invadens.

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