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PubMed2005

Hepatitis C virus (HCV) infection and lymphoproliferative disorders

Several infectious agents have been associated with development of lymphoproliferative disorders. Among these is hepatitis C virus (HCV), which infects more than 200 million people worldwide. HCV infection has been linked to progression of type II mixed cryoglobulinemia (MC) syndrome and has also been suggested to contribute to development of B-cell non-Hodgkin's lymphoma (NHL). Mechanisms responsible for development of lymphoproliferative disorders among HCV-positive patients remain unclear. Accumulating evidence supports a model in which chronic stimulation of B-cells by antigens associated with HCV infection causes nonmalignant B-cell expansion that may evolve into B-cell NHL. The course of disease among HCV-positive B-cell NHL patients may be complicated by coinfection with other infectious agents. This possibility has been explored by studies that have investigated potential interactions between HCV and human immunodeficiency virus (HIV) as well as between HCV and Epstein-Barr virus (EBV). Further characterization of the mechanisms by which HCV promotes development of lymphoproliferative disorders may improve diagnosis, classification, and treatment of these conditions.

Antiviral Agents↗
PubMed1990

Pediatric AIDS: treatment and outcome of patients.

The treatment of pediatric patients with HIV infection/AIDS is structured according to the clinical classification of the disease by the Centers for Disease Control; it involves prophylaxis, therapy against the human immunodeficiency virus, and therapy for the opportunistic infections and non-infectious complications of this disease. In spite of all these forms of therapy, the universal outcome of HIV infection/AIDS is the death of the patients. Prevention remains the only effective means to curb this epidemic.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Study of genetic reassortment between two human rotaviruses.

Eight different human rotavirus strains were adapted to replicate in cell culture. In vitro, rotavirus genetic reassortment has been performed between two virus strains, one with a long pattern of segmented genomic RNAs and the other with a short pattern in the electrophoretic mobility of genomic RNAs. This genetic reassortment was detectable despite the lack of selective markers in the parental strains. Moreover, some of the reassorted virus exhibited mixed RNA patterns containing extra genomic RNAs resembling those found in clinical specimens. These viruses with mixed RNA band patterns could segregate their supplementary segments after successive passages in cell culture. Finally it has been shown that classification of genomic segments in long and short electropherotypes should not only be based on their relative size but also by their ability to reassort with the genetically equivalent segment.

Cell Line↗
PubMed1995

Determination and comparative analysis of the small RNA genomic sequences of California encephalitis, Jamestown Canyon, Jerry Slough, Melao, Keystone and Trivittatus viruses (Bunyaviridae, genus Bunyavirus, California serogroup).

The nucleotide sequences of the small (S) genomic RNAs of six California (CAL) serogroup bunyaviruses (Bunyaviridae: genus Bunyavirus) were determined. The S RNAs of two California encephalitis virus strains, two Jamestown Canyon virus strains, Jerry Slough virus, Melao virus, Keystone virus and Trivittatus virus contained the overlapping nucleocapsid (N) and non-structural (NSs) protein open reading frames (ORFs) as described previously for the S RNAs of other CAL serogroup viruses. All N protein ORFs were 708 nucleotides in length and encoded a putative 235 amino acid gene product. The NSs ORFs were found to be of two lengths, 279 and 294 nucleotides, which potentially encode 92 and 97 amino acid proteins, respectively. The complementary termini and a purine-rich sequence in the 3' non-coding region (genome-complementary sense) were highly conserved amongst CAL serogroup bunyavirus S RNAs. Phylogenetic analyses of N ORF sequences indicate that the CAL serogroup bunyaviruses can be divided into three monophyletic lineages corresponding to three of the complexes previously derived by serological classification. The truncated version of the NSs protein, which is found in five CAL serogroup bunyaviruses, appears to have arisen twice during virus evolution.

Amino Acid Sequence↗
PubMed1999

Detection of avian leukosis virus in albumen of chicken eggs using reverse transcription polymerase chain reaction.

A reverse transcriptase polymerase chain (RT-PCR) assay was developed to detect avian leukosis retrovirus (ALV) in egg albumen. Eggs of Single Comb White Leghorns were from a commercial breeder (stock F) and from a pathogen-free flock (stock N). RT-PCR was undertaken on isolated RNA from 20 unfertilized egg samples using seven sets of primers that correspond to the ALV gp85 envelope glycoprotein which determines the ALV subgroup classification. An ELISA assay for ALV gs antigen of egg albumen was positive for all stock F birds tested and negative for all stock N birds. Virus isolation was undertaken by inoculating egg albumen, feather pulp, or blood from five stock F chickens onto cultures of chicken embryo fibroblasts (C/E). IFA analysis of the inoculated C/E cultures indicated that all stock F birds tested contained infectious ALV. For the virus-positive stock F chickens, RT-PCR analyses using primers designed to detect all ALV subgroups detected ALV in 15/15 (100%) egg albumen samples, while primers designed to detect subgroup A ALV were positive for 12/15 (80%) egg albumen samples. RT-PCR products were not detected from five egg albumen samples from five stock N chickens by any primer sets. Direct sequencing using primers specific for subgroup A ALV verified the viral subgroup in the RT-PCR amplification products. The combined use of RT-PCR and direct sequencing of the RT-PCR product provides a new approach for identifying ALV-infected poultry.

Albumins↗
PubMed1984

Virulence in African swine fever: its measurement and implications.

A method of measuring and expressing the virulence of African swine fever virus in numerical terms was developed. Seventeen viruses (13 hemadsorbing and 4 nonhemadsorbing) were tested and classified into 3 groups: highly infectious and highly virulent, highly infectious and moderately virulent, and slightly infectious and slightly virulent. This classification was based on the number of 50% hemadsorption unit (HA50) or TCID50 required to produce 1 LD50 for swine, the number of HA50 or TCID50 required to produce one 50% pig infectious dose (PID50), and the number of PID50 required for each LD50. The virulent virus (group 1) required less than or equal to 10 virus units (HA50 or TCID50) for 1 PID50 and LD50 (highly infectious and highly lethal), respectively, and had a ratio of 1.0 for PID50/LD50, ie, all infected pigs died from acute African swine fever. Tengani, L'60, and DR-I isolants and nonhemadsorbing viruses of Haiti-1 isolant belong to this group. The moderately virulent virus (group 2) required less than 10 virus units for 1 PID50 and 20 to 562 virus units for 1 LD50 (highly infectious and moderately lethal), respectively, and recoveries from the clinical disease and immunologic deaths were frequent. Madrid '75, Haiti-1, DR-II, and BR-I isolants belong to this group. The slightly virulent virus (group 3) required 56 to 10,000 virus units for 1 PID50 and 56,200 to 3,120,000 virus units for 1 LD50 (slightly infectious and less lethal).(ABSTRACT TRUNCATED AT 250 WORDS)

African Swine Fever↗
PubMed1989

The use of 3' non-coding nucleotide sequences in the taxonomy of potyviruses: application to watermelon mosaic virus 2 and soybean mosaic virus-N.

The sequence of the 3' 1106 nucleotides of the watermelon mosaic virus 2 (WMV 2) genome has been determined. The sequence contains the complete coding region of the viral coat protein followed by a 3' untranslated sequence of 251 nucleotides. When these sequences were compared with the equivalent regions of the N strain of soybean mosaic virus (SMV-N), the coat protein coding regions were 82% homologous, whereas the 3' untranslated sequences were 78% homologous. Optimal alignment of the 3' untranslated regions of RNA from 13 strains of seven other distinct potyviruses revealed that the degree of homology between strains was in the range 83 to 99%. In contrast, the sequences from distinct viruses had identities in the range 39 to 53%, comparable to the level of identity found between the 3' non-coding regions of viruses from unrelated plant virus groups. On the basis of these results, WMV 2 and SMV-N could be regarded as strains of one virus. These results also suggest that the sequence of the 3' untranslated region of the potyvirus genome may be an accurate marker of genetic relatedness and could serve as an aid to identification and classification of potyviruses.

Amino Acid Sequence↗
PubMed2002

Respiratory syncytial virus-coded pediatric hospitalizations, 1997 to 1999.

BACKGROUND: The recent number and rate of infant hospitalizations with a respiratory syncytial virus (RSV)-coded diagnosis have not been published. METHODS: Retrospective data analysis. National Hospital Discharge Survey data for 1997 to 1999 were analyzed for discharges of infants < 1 year old with an RSV-coded diagnosis (ICD-9-CM 466.11, 480.1, 079.6). Hospitalization rates were estimated with annual midyear Census data. RESULTS: RSV bronchiolitis was the leading primary diagnosis annually for all infants hospitalized for any reason. Between 1997 and 1999, 297 684 RSV-coded discharges of infants with an RSV-coded diagnosis occurred. The associated hospitalization rate was 25.2 per 1000 infants. RSV-coded discharges peaked in February. CONCLUSION: RSV bronchiolitis was the leading cause of hospital admissions of infants younger than age 1 year for any reason between 1997 and 1999.

Acute Disease↗
PubMed1978

[Electron microscopy: A clinically useful, desirable or useless tool in kidney biopsy diagnostics? (author's transl)].

Electron microscopic investigation of renal biopsies is indispensable in cases of suspected Alport's syndrome, benign (familial) hematuria, nail patella syndrome as well as for the identification of viruses, virus-like endothelial tubular structures and crystalloid deposits in cryoglobulinemia. Additional valuable information is provided for all other glomerular nephropathies especially for exact classification of glomerulonephritis. Electron microscopy can by no means be a substitute for light microscopy or immunofluorescence, respectively. Provided that clinical-pathological cooperation is optimal, best results can be obtained by simultaneous application of all three methods.

Biopsy↗
PubMed1990

Clinicopathologic features of hepatocellular carcinoma in young patients.

To investigate clinicopathologic characteristics of hepatocellular carcinoma (HCC) in young adults, excised tumors from 21 patients younger than 45 years (young group) were compared with findings in tumors from 204 patients older than 45 (old group). In the young group HCC showed (1) a high incidence of positive hepatitis B virus surface antigen (HBsAg) (young 71.4% versus old 20.1%); (2) relatively well-preserved hepatocellular function (indocyanine green test; young 10.7 +/- 8.8% versus old 20.6 +/- 10.8%); (3) low incidence of histologically verified concomitant cirrhosis (young 52.4% versus old 78.4%); and (4) a more advanced stage of the disease in TNM classification (Stage III; young 52.4% versus old 18.1%). With respect to survival rates achieved by surgery, there was no statistically significant difference between the two groups. Thus, hepatitis B virus may relate to the occurrence of HCC in the young patients. Despite the advanced stage in the young group, survival rate after surgery was comparable with that achieved in the old group. These observations mean that a close periodic surveillance of young adults with a positive HBsAg is required to detect HCC at an early stage. Treatment of patients with HBsAg using interferon or vidarabine and hepatitis B vaccine should be made to convert HBsAg to negative in these individuals.

Adult↗
PubMed2001

Development of an env gp41-based heteroduplex mobility assay for rapid human immunodeficiency virus type 1 subtyping.

The gp120 region of the human immunodeficiency virus type 1 (HIV-1) envelope (env) gene exhibits a high level of genetic heterogeneity across the group M subtypes. The heteroduplex mobility assay (HMA) has successfully been used to assign subtype classifications, but C2V5 primers often fail to amplify African strains. We developed an env gp41-based HMA for which the target sequence is amplified with highly conserved gp41 primers, known to efficiently amplify nucleic acids from HIV-1 group M, N, and O viruses. By using gp41 from a new panel of reference strains, the subtype assignments made by our modified HMA were concordant with those obtained by sequencing and phylogenetic analysis of 34 field strains from 10 countries representing subtypes A to G. Testing of field strains from Nigeria further demonstrated the utility of this modified assay. Of 28 samples, all could be amplified with gp41 primers but only 17 (60.7%) could be amplified with the standard C2V5 primers. Therefore, gp41-based HMA can be a useful tool for the rapid monitoring of prevalent subtypes in countries with divergent strains of circulating HIV-1.

DNA, Viral↗
PubMed2006

Validation and comparison of indexes for fibrosis and cirrhosis prediction in chronic hepatitis C patients: proposal for a pragmatic approach classification without liver biopsies.

Noninvasive indexes have been developed to predict fibrosis staging. The aim of this study was to assess the diagnostic accuracy of these indexes in comparison with liver histology in hepatitis C virus (HCV)-infected patients. A total of 235 consecutive patients with HCV infection from the Fibropaca multicentre independent study were included in this paper. FibroTest (FT), aspartate aminotransferase to platelet ratio index (APRI) and Forns score were assessed in the cohort and compared with liver histology performed on the same day. The main end point was the area under characteristic curves (AUCs) for the diagnosis of significant fibrosis (F2-F4) and cirrhosis (F4) by the METAVIR classification. Mean age was 46 (+/-11) years, 55% were males, 42% (n = 99) had significant fibrosis (F2-F4) and 7% (n = 16) had cirrhosis (F4). For the diagnosis of significant fibrosis, respective AUCs of FT, APRI and Forns score were 0.81 (95% confidence interval: 0.76-0.86), 0.71 (0.67-0.79) and 0.76 (0.70-0.82); for cirrhosis prognosis, AUCs of FT and APRI were 0.82 (0.77-0.87) and 0.81 (0.76-0.86) (AUCs not significantly different). Using each index independently, all patients were classified by FT, 214 (91%) patients were classified by APRI and 129 (55%) by Forns score. There were significantly more cases of discordances between APRI and liver biopsy than between FT or Forns score and liver biopsy (P < 0.05). Performing all scores (FT, Forns and APRI) without liver biopsy allowed fibrosis to be well evaluated in 191 patients (81.3%), including patients with FT failure. Liver biopsy remained mandatory to evaluate fibrosis in 44 patients (18.7%). Our study shows that performing all the tests and liver biopsy improves the diagnostic accuracy for liver fibrosis in chronic hepatitis C patients without patent comorbidities. The combination of all tests with liver biopsy allowed 225/235 (96%) patients to be correctly classified. The combination of all tests without liver biopsy allowed 191/235 (81.3%) patients to be correctly classified; liver biopsy remained mandatory in some patients (18.7%).

Adult↗
PubMed2003

Limitations of TaqMan PCR for detecting divergent viral pathogens illustrated by hepatitis A, B, C, and E viruses and human immunodeficiency virus.

Recent events illustrate the imperative to rapidly and accurately detect and identify pathogens during disease outbreaks, whether they are natural or engineered. Particularly for our primary goal of detecting bioterrorist releases, detection techniques must be both species-wide (capable of detecting all known strains of a given species) and species specific. Due to classification restrictions on the publication of data for species that may pose a bioterror threat, we illustrate the challenges of finding such assays using five nonthreat organisms that are nevertheless of public health concern: human immunodeficiency virus (HIV) and four species of hepatitis viruses. Fluorogenic probe-based PCR assays (TaqMan; Perkin-Elmer Corp., Applied Biosystems, Foster City, Calif.) may be sensitive, fast methods for the identification of species in which the genome is conserved among strains, such as hepatitis A virus. For species such as HIV, however, the strains are highly divergent. We use computational methods to show that nine TaqMan primer and probe sequences, or signatures, are needed to ensure that all strains will be detected, but this is an unfeasible number, considering the cost of TaqMan probes. Strains of hepatitis B, C, and E viruses show intermediate divergence, so that two to three TaqMan signatures are required to detect all strains of each virus. We conclude that for species such as hepatitis A virus with high levels of sequence conservation among strains, signatures can be found computationally for detection by the TaqMan assay, which is a sensitive, rapid, and cost-effective method. However, for species such as HIV with substantial genetic divergence among strains, the TaqMan assay becomes unfeasible and alternative detection methods may be required. We compare the TaqMan assay with some of the alternative nucleic acid-based detection techniques of microarray, chip, and bead technologies in terms of sensitivity, speed, and cost.

Computational Biology↗
PubMed2006

Lowering standards of clinical waste management: do the hazardous waste regulations conflict with the CDC's universal/standard precautions?

Clinical waste is a costly and troublesome commodity. Comprising the detritus of medical care, the foremost hazard is the risk of infection from micro-organisms present in these wastes. Infection commonly occurs through penetrating injury, the so-called 'sharps' or 'needlestick' injury, although contamination of non-intact skin or splashes to the eye may transmit infection. Bloodborne viruses (hepatitis B, hepatitis C, human immunodeficiency virus) are the most serious threat, although respiratory, soft tissue and enteric infections are not unknown. The European Hazardous Waste Directive, that harmonizes the categorization and control of wastes, permits downregulation of clinical wastes where the risk of infection may be low. Although strengthened by the requirement for risk assessment in waste classification, UK regulatory guidance promoting classification of some clinical wastes as non-hazardous completely ignores the Centers for Disease Control and Prevention's Universal Precautions for the prevention of transmission of human immunodeficiency virus, hepatitis B virus and other bloodborne pathogens in healthcare settings, which seek to prevent bloodborne virus infection in healthcare workers and others, and the more extensive Standard Precautions that extend these principles to the prevention of healthcare-associated infections and the environmental spread of nosocomial pathogens. By creating a potent cost driver encouraging downregulation of some clinical wastes, UK legislation based on the European Hazardous Waste Directive conflicts with the CDC's Universal/Standard Precautions.

Animals↗
PubMedDate not supplied

Computer-operated scanning analysis of FITC-labelled measles virus in cell cultures.

FITC-labelled measles virus antigen in infected cells was analysed by computer-operated scanning fluorometry, printed out by a mosaic printer according to a predetermined classification, and by a coordinate-recorder as a perspective image. The three-dimensional print-out of the topographic distribution of antigen accumulations in the cells can be optimized by a variation of the angle of view.

Animals↗
PubMed2000

Atlas and histologic classification of tumors of the rat mammary gland.

Studies performed in experimental animal models have demonstrated that mammary cancer is a complex multistep process that can be induced either by chemicals, radiation, viruses, or genetic factors. Rodent models have been useful for dissecting the initiation, promotion, and progression steps of mammary carcinogenesis. Chemically induced mammary tumors, such as those induced by 7,12-dimethylbenz(a)anthracene and N-methyl-N-nitrosourea, are, in general, hormone-dependent adenocarcinomas whose incidence, number of tumors per animal, tumor latency, and tumor type are influenced by the age, reproductive history, and endocrinologic milieu of the host at the time of carcinogen exposure as well as by diet and the dose of carcinogen administered. There is a need to classify tumors according to their histopathological type because those characteristics have implications in the interpretation of experimental data. In the classification presented here we attempt to provide a working framework for diagnosis of the type of lesions found in the mammary glands of rats treated with chemical carcinogens or radiation and to clarify criteria for establishing the basic biological characteristics of tumors.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1976

The isolation and some biological properties of a variant avian infectious bronchitis virus.

A virus isolated from a respiratory disease in chickens was identified as infectious bronchitis virus (IBV). By serum neutralisation tests the virus was shown to be serologically distinct from the Massachusetts type but to possess a one-way relationship with the Connecticut type. Experimentally, it caused a relatively mild respiratory disease in baby chicks. Vaccination of young chicks with H-120 Massachusetts IBV vaccine afforded a high degree of protection against challenge with the isolate. Some problems relating to the isolation and classification of field strains of IBV are briefly discussed.

Animals↗