Biomedical subjects

Cesar D Fermin

Publications and source records attributed to Cesar D Fermin.

7 recordsLinked to original sources

PubMed2005

Seroreactivity to A-type retrovirus proteins in a subset of cats with hyperthyroidism.

The thyroid gland is afflicted in several endocrine, autoimmune, and malignant diseases. Previous studies detected immunoreactivity against proteins of a human intracisternal A-type retroviral particle type-I (HIAP-I) in serum samples from the majority of patients with Graves' disease, an autoimmune disease of the thyroid that can also affect other organs, most prominently the eyes. To determine whether hyperthyroid animals might provide a model for the retroviral involvement in thyroid autoimmunity, serum samples from 32 cats (21 hyperthyroid and 11 controls) and 10 hypothyroid dogs were examined for immunoreactivity with HIAP-I using a Western blot technique. Of the 21 hyperthyroid cats 15 (71.4%) were HIAP-I positive, while only 2 of 11 (11.8%) control animals without endocrine pathology were positive. No significant correlations were seen between HIAP seroreactivity and serum thyroid hormone levels (T3 and T4), age, gender, treatment history, vaccination status, or weight. No seroreactivity to HIAP-I was detected in hypothyroid dogs. An examination of HIAP-I reactivity in feline leukemia virus (FeLV)-seroconverting cats found that 7/9 (78%) animals viremic for FeLV-A showed an alteration in HIAP serology, whereas only 1/7 (14%) nonviremic animals showed a change in HIAP-I serology. These results suggest that it may be possible to develop an animal (feline) model for the role of retroviruses in thyroid autoimmune diseases.

Animals↗

PubMed2005

Slow virus disease: deciphering conflicting data on the transmissible spongiform encephalopathies (TSE) also called prion diseases.

The transmissible spongiform encephalopathies (TSE) that manifest as Creutzfeldt-Jakob disease in humans, as scrapie in sheep and goats, mad cow disease in cattle, or chronic wasting disease in cervids (deer) represent a serious human health crisis and a significant economical problem. Despite much research, the nature of the elusive pathogen directly involved with TSE is currently unresolved. This article reviews current pathogen-cell plasma membrane properties, showing that the primary biochemical marker of the prion disease is used as a receptor by the intracellular bacterium Brucella abortus. Such observation makes plausible the role for the prion in the pathogenesis of TSE, and supports the concept that Spiroplasma, a wall-less bacterium, may be a transmissible agent of TSE. Over the past three decades, we have published convincing evidence that Spiroplasma infection is associated with TSE. The bacterial-prion-receptor concept by other laboratories support a model for TSE wherein a Spiroplasma bacterium can bind to prion receptors (alone or with anchors) on the cell surface lipid raft, allowing entry of the microbe into the cell to initiate infection. The relevance of this new concept is that it offers a new window for future research involving a bacterium in the pathogenesis of TSE. Data from the bacterial-prion-receptor model will aid in the development diagnostic tests and/or treatment protocols for TSE.

Animals↗

PubMed2005

Dengue in the Dominican Republic: epidemiology for 2004.

The Dominican Republic (DR) has experienced tremendous increase in the number of cases of dengue virus (DENV) reported in the past few years. There are four serotypes of DENV (1-4), and each can cause classic dengue fever (DF), dengue hemorrhagic fever (DHF), or dengue shock syndrome (DSS). DENV-1-4 are currently circulating in the DR; however, the Department of Epidemiology of the Dominican Republic (DIEGPI) has been able to isolate only DENV-2 and DENV-4. In the DR, the development of DENV infection occurred primarily in the second semester of the year. Since the DR instituted a vigilant approach to dengue infections, there have been three major outbreaks detected: one in 1998, one in 2000, and one in 2002. DF is the clinical presentation most currently seen at clinics, accounting for about 75% of cases, while patients with DHF account for about 19% of cases seen. Currently, there are seven provinces in which the total number of dengue cases per 100,000 inhabitants is higher than 32. With a vigilant approach, the DR should continue to see success in controlling the DENV outbreak.

DNA, Viral↗

PubMed2005

Involvement of human intracisternal A-type retroviral particles in autoimmunity.

Prior studies have linked retroviruses to various arthropathies and autoimmune diseases. Sjögren's syndrome (SS), a systemic autoimmune disease, is characterized by aggressive infiltration of lymphocytes into the salivary and lacrimal glands, resulting in destruction of the glands and dry mouth and eyes (sicca syndrome). The infiltrating lymphocytes in SS may become overtly malignant, and thus, the incidence of lymphoma is greatly increased in SS patients. A human intracisternal A-type retroviral particle type I (HIAP-I) has been isolated from persons with SS. HIAP-I shares a limited number of antigenic epitopes with human immunodeficiency virus (HIV), but is distinguishable from HIV by morphological, physical, and biochemical criteria. A substantial majority of patients with SS or systemic lupus erythematosus (SLE) have serum antibodies to the proteins of this human retrovirus. Fewer than 3% of the normal blood donor population have antibodies to any HIAP-associated proteins. A second type of a human intracisternal A-type retrovirus, HIAP-II, was detected in a subset of patients with idiopathic CD4 lymphocytopenia (ICL), an AIDS-like immunodeficiency disease. Most HIAP-II positive ICL patients were also antinuclear antibody positive. Reviewed here are additional studies from several laboratories suggesting that HIAP or related viruses may be involved in SLE and other autoimmune conditions. Additionally, results of comprehensive surveys of autoimmune patients to determine seroreactivity to HIAP, and other human retroviruses, including HIV and human T-lymphotropic virus type I, are reported.

Autoimmune Diseases↗

PubMed2005

Alpha interferon inhibits translation mediated by the internal ribosome entry site of six different hepatitis C virus genotypes.

Certain genotypes of hepatitis C virus (HCV) respond less often than others to treatment with interferon (IFN). The mechanisms for this differential response are not known. In this report antiviral effects of IFN-alpha2b on translation were examined in a hepatic cell line using chimeric clones of internal ribosome entry site (IRES) sequences from six different HCV genotypes and the green fluorescence protein (GFP) gene. As a control, IFN action at the level of the IRES was examined in the presence of different cytokines. It was determined that IFN-alpha2b specifically inhibited the translation of GFP mediated by IRES sequences from six major HCV genotypes in a concentration-dependent manner. Other cytokines including tumour necrosis factor alpha, transforming growth factor beta 1, interleukin 1 and interleukin 6 have no inhibitory effect. The inhibition of translation in these experiments was not due to extensive intracellular degradation of IRES-GFP mRNA. These results suggest that the antiviral action of IFN-alpha2b blocks IRES-mediated translation and this effect is the same among HCVs of other genotypes.

Genotype↗

PubMed2002

Bleomycin sensitivity of mice expressing dominant-negative p53 in the lung epithelium.

The chemotherapeutic drug bleomycin causes DNA damage and apoptosis in the lungs of mice within hours of endotracheal instillation followed by inflammation and fibrosis weeks later. The p53 tumor suppressor protein mediates cellular responses to DNA damage, including induction of apoptosis, but the effects of p53 activation in the various cell types of the lung during bleomycin-induced pulmonary fibrosis remain unclear. We show here that a transgene with a dominant-negative mutant form of human p53 expressed from the surfactant protein C promoter sensitizes mice to bleomycin-induced lung injury. The bleomycin-exposed transgenic animals display more severe lung pathology with associated collagen deposition and more pronounced lung eosinophilia than simultaneously exposed nontransgenic littermates. These observations suggest that compromising p53 function in the alveolar epithelium impairs recovery of the lung from bleomycin-induced injury.

Animals↗

PubMed2002

Avian dark cells.

Dark cells (DCs) of mammalian and non-mammalian species help to maintain the homeostasis of the inner ear fluids in vivo. Although the avian cochlea is straight and the mammalian cochlea is coiled, no significant difference in the morphology and/or function of mammalian and avian DCs has been reported. The mammalian equivalent of avian DCs are marginal cells and are located in the stria vascularis along a bony sheet. Avian DCs hang free from the tegmentum vasculosum (TV) of the avian lagena between the perilymph and endolymph. Frame averaging was used to image the fluorescence emitted by several fluorochromes applied to freshly isolated dark cells (iDCs) from chickens (Gallus domesticus) inner ears. The viability of iDCs was monitored via trypan blue exclusion at each isolation step. Sodium Green, BCECF-AM, Rhodamine 123 and 9-anthroyl ouabain molecules were used to test iDC function. These fluorochromes label iDCs ionic transmembrane trafficking function, membrane electrogenic potentials and Na+/K+ ATPase pump's activity. Na+/K+ ATPase pump sites, were also evaluated by the p-nitrophenyl phosphatase reaction. These results suggest that iDCs remain viable for several hours after isolation without special culturing requirements and that the number and functional activity of Na+/K+ ATPase pumps in the iDCs were indistinguishable from in vivo DCs. Primary cultures of freshly iDCs were successfully maintained for 28 days in plastic dishes with RPMI 1640 culture medium. The preparation of iDCs overcomes the difficulty of DCs accessability in vivo and the unavoidable contamination that rupturing the inner ear microenvironments induces.

Animals↗