Virus-specific humoral immune response in Bulgarian COVID-19 patients with varying disease severity.

Introduction: Our study aimed to analyze virus-specific humoral immune responses in COVID-19 patients with varying disease severity.

Methodology: A total of 109 serum samples from 87 patients, symptomatic for COVID-19 were studied using anti-SARS-CoV-2 immunoassays detecting different classes of immunoglobulins.

Results: Clinical samples were divided into 2 groups - collected up to and more than 2 weeks post-onset of symptoms (PoS).

Varicella zoster virus infection in neurological patients in Bulgaria.

The clinical manifestations of neurological complications associated with varicella zoster virus (VZV) are non-specific and indistinguishable from those of other viral infections. Therefore, the definite diagnosis requires evidence of VZV infection in cerebrospinal fluid (CSF). The aim of this study was to determine the frequency of VZV DNA detection in CSF of patients with neurological diseases in order to obtain information concerning involvement of VZV infection in neuropathology in the country.

Systematic Review of the Epidemiological Burden of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Across Europe: Current Evidence and EUROMENE Research Recommendations for Epidemiology.

This review aimed at determining the prevalence and incidence of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) in Europe. We conducted a primary search in Scopus, PubMed and Web of Science for publications between 1994 and 15 June 2019 (PROSPERO: CRD42017078688). Additionally, we performed a backward-(reference lists) and forward-(citations) search of the works included in this review.

Cytomegalovirus, Epstein-Barr virus, and human herpesvirus-6 infections in patients with myalgic еncephalomyelitis/chronic fatigue syndrome.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disabling multisystem chronic disease. The etiology and pathogenesis of ME/CFS are unknown. Infections of cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpesvirus-6 (HHV-6) are suspected as etiological agents for ME/CFS.

Chronic viral infections in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Background And Main Text: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex and controversial clinical condition without having established causative factors. Increasing numbers of cases during past decade have created awareness among patients as well as healthcare professionals. Chronic viral infection as a cause of ME/CFS has long been debated.

Prevalence and incidence of myalgic encephalomyelitis/chronic fatigue syndrome in Europe-the Euro-epiME study from the European network EUROMENE: a protocol for a systematic review.

Introduction: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic disease involving central nervous system and immune system disorders, as well as cardiovascular abnormalities. ME/CFS is characterised by severe chronic fatigue lasting for at least 6 months, including clinical symptoms such as tender cervical or axillary lymph nodes, muscle pain, joint pain without swelling or redness, post-exertional malaise for more than 24 hours and unrefreshing sleep. Studies on the epidemiology of ME/CFS in Europe only include single countries and, therefore, the prevalence and incidence of ME/CFS in Europe (as a whole) is unknown.

Human papillomavirus prevalence in lung carcinomas in Bulgaria.

A possible association between high-risk human papillomaviruses (HPV) and lung cancer has been investigated for decades with discrepant results. The aim of this study was to determine the prevalence of HPV16 and 18 in Bulgarian patients with lung cancer. Two hundred and nine biopsy specimens from patients with histologically proven lung cancer and without cancer were analyzed.

Detection of Merkel Cell Polyomavirus in Respiratory Tract Specimens.

Objective: The role of Merkel cell polyomavirus (MCPyV) as a respiratory pathogen is controversial. The aim of this study was to determine the prevalence of MCPyV in patients with acute respiratory diseases and chronic lung diseases, including lung cancer, in order to evaluate the association between MCPyV infection and respiratory diseases.

Methods: This study included 221 specimens (133 nasopharyngeal swabs and 88 lung biopsy specimens) obtained from patients with acute respiratory diseases and chronic lung diseases, including lung cancer.

The European ME/CFS Biomarker Landscape project: an initiative of the European network EUROMENE.

Myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) is a common and severe disease with a considerable social and economic impact. So far, the etiology is not known, and neither a diagnostic marker nor licensed treatments are available yet. The EUROMENE network of European researchers and clinicians aims to promote cooperation and advance research on ME/CFS.

Cervical Viral Infections among Asymptomatic Bulgarian Women.

Aim: Although sexually transmitted viral infections are significant and increasing public health concern, little is known about their prevalence among Bulgarian women. The aim of this study was to investigate cervical viral infections in asymptomatic women.

Methods: The study group included 52 randomly selected asymptomatic female volunteers from Bulgarian border town Kardzhali.

The use of recombinant pseudotype virus-like particles harbouring inserted target antigen to generate antibodies against cellular marker p16INK4A.

Protein engineering provides an opportunity to generate new immunogens with desired features. Previously, we have demonstrated that hamster polyomavirus major capsid protein VP1-derived virus-like particles (VLPs) are highly immunogenic and can be employed for the insertion of foreign epitopes at certain surface-exposed positions. In the current study, we have designed pseudotype VLPs consisting of an intact VP1 protein and VP2 protein fused with the target antigen--cellular marker p16(INK4A)--at its N terminus.

Prevalence of human papillomavirus infection among female sex workers in Bulgaria.

The present study estimates the prevalence and risk factors of human papillomavirus (HPV) infection among female sex workers (FSWs) in Bulgaria. HPV DNA was detected by polymerase chain reaction (PCR) in 43.4% of FSWs.

Human papillomavirus prevalence in invasive cervical carcinomas in Bulgaria.

Background: Although Bulgaria has one of the highest rates of cervical cancer incidence and mortality in the EU, data on HPV type distribution are limited.

Aim: To determine the prevalence of HPV types 16 and 18 in archival specimens from cervical cancer cases from Bulgaria.

Methods: A total of 145 formalin-fixed, paraffin-embedded tissue samples from women with histologically proven invasive squamous cell carcinoma of the uterine cervix were available for this study.

Electron-microscopic immunocytochemical study of the intracellular transport of the viral glycoproteins in ts1, a mutant of Moloney murine leukemia virus.

The transport and localization of env-proteins of ts1 virus (a paralytogenic temperature-sensitive mutant of Moloney murine leukemia virus) in infected cells of the TB cell line have been studied at the ultrastructural level. It was found that the envelope precursor polyprotein gPr80-env of ts1 was inefficiently transported out of the endoplasmic reticulum at the restrictive temperature. It was speculated that inefficient transport correlates with inefficient processing of gPr80env into gp70 and Prp15E and leads to paralytic disease.

Correlation of specific virus-astrocyte interactions and cytopathic effects induced by ts1, a neurovirulent mutant of Moloney murine leukemia virus.

ts1 is a highly neuropathogenic and lymphocytopathic mutant of Moloney murine leukemia virus TB (MoMuLV-TB). We previously reported that the primary neuropathogenic determinant of ts1 maps to a single amino acid substitution, Val-25-->Ile, in precursor envelope protein gPr80env. This Val-25-->Ile substitution apparently renders gPr80env inefficient for transport from the endoplasmic reticulum to the Golgi apparatus.

Murine leukemia virus induced central nervous system diseases.

The ts1 mutant of Moloney murine leukemia virus TB (MoMuLV-TB) causes a degenerative neurologic and immunologic disease in mice characterized by development of spongiform encephalomyelopathy that results in hind-limb paralysis, marked thymic atrophy associated with immunodeficiency, and generalized body wasting. T cells, particularly CD4+ helper T cells, play a key role in the pathogenesis of the disease induced by ts1. Therefore, ts1 is unique among the described murine retroviruses in its ability to afflict both the central nervous system (CNS) and the T-cell compartment of the immune system in the same host.

Modulation of experimental allergic encephalomyelitis by a host-versus-graft reaction: a clinicopathological study.

The effect of timing of a local host-versus-graft reaction on the induction of acute experimental allergic encephalomyelitis (EAE) was studied in guinea pigs. 20 x 10(7) gamma-irradiated allogeneic cells injected 4 days after encephalitogenic challenge resulted in the development of EAE with an earlier onset, an increased delayed-type hypersensitivity (DTH) response and an increase in lymphoid cell infiltration in the spinal cord. Challenge with allogeneic cells on days -4 and -7, however, produced a delay in onset and a protracted course of disease, with 30-40% of the animals recovering.

Type A oncornavirus-like particles in turkey bone marrow cells transformed by avian leukemia virus.

Type A oncornavirus-like particles (TAOLP) were found in the cytoplasm of turkey bone marrow cells transformed by strain Mc-31 avian leukemia virus. They resembled morphologically the cores of budding virions and the cores of immature extracellular Mc-31 virus particles. TAOLP were observed more often in T3Mc31 cells where cytopathological changes existed.

[Ultrastructure of the retrovirus of human myeloma cells].

Extracellular population of oncovirus of continuous human myeloma RPM18226 cells contains type D virions in addition to morphological types of A and C particles. Nucleoids of type D oncoviruses are encapsulated. Peculiar contacts morphologically similar to slit-like links between eucaryots were found between adjacent extracellular RPM18226V virions.