Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “virus classification”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,189 records · Page 66Linked to original sources
PubMed1995

Hodgkin's disease.

BACKGROUND: Over three time periods, 1973-1977, 1978-1982, and 1983-1987, the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute collected all cases of Hodgkin's disease in designated geographic regions representative of the United States as a whole. METHODS: The authors reviewed the data pertaining to 9418 microscopically confirmed cases of Hodgkin's disease and focused on trends that emerged over the time intervals of this study. RESULTS: Hodgkin's disease had a bimodal distribution of age-specific incidence rates with two peaks in the age groups of 15-34 years and older than 55 years. Since 1973, the incidence of Hodgkin's disease in the younger age group increased progressively as a result of a marked increase in the incidence of the nodular sclerosis subtype. From the period 1973-1977 to 1983-1987, the age-adjusted incidence rate of nodular sclerosis rose from 1.1 to 1.6 per 100,000. In 1983-1987, nodular sclerosis represented 57.7% of Hodgkin's disease and occurred most often in whites, with an equal sex ratio. In females, this increase in incidence over time was most dramatic in young adult women. The overall incidence of the mixed cellularity subtype, 23.4% of Hodgkin's disease, remained stable although the age-specific incidence rate increased progressively in black males older than age 40 years. The incidence of the lymphocytic predominance subtype, 6.0% of Hodgkin's disease, remained stable over time, with a slight increase in adults older than age 50 years. The lymphocytic depletion subtype, 3.8% of Hodgkin's disease, occurred predominantly in the elderly; its incidence decreased, most likely the result of changes in diagnostic criteria, with many cases being reclassified as non-Hodgkin's lymphoma (NHL). Similarly, unclassifiable cases of Hodgkin's disease designated as miscellaneous, 9.1% of Hodgkin's disease, decreased over time, probably the result of improved classification. Nevertheless, a subset of cases of Hodgkin's disease remained difficult to subclassify. The human immunodeficiency virus (HIV) epidemic appears to be associated with an increased incidence of Hodgkin's disease in San Francisco County in adult males age 30-49 years, a population known to have a high prevalence of HIV infection. CONCLUSION: The SEER data suggest that Hodgkin's disease is a heterogeneous entity composed of at least two different diseases--nodular sclerosis and mixed cellularity. Over the time course of this study, the incidence of nodular sclerosis increased dramatically, particularly in adolescents and young adults, whereas mixed cellularity remained stable. The incidence of Hodgkin's disease in the elderly decreased, most likely the result of our improved ability to diagnose both Hodgkin's disease and NHL and the realization that many cases of NHL had been misclassified as Hodgkin's disease. This decrease in Hodgkin's disease occurred predominantly in the lymphocytic depletion and miscellaneous groups.

Adolescent↗
PubMed2004

New daily persistent headache: clinical and serological characteristics in a retrospective study.

We present a retrospective clinical study of 18 cases of new daily persistent headache (NDPH), a rare chronic headache, included in the fourth chapter of the II IHS classification; the pathophysiology of NDPH is unknown but a link with viral infections (especially Epstein-Barr virus (EBV)) has been suggested. Comparing our series with the other two published until now, we did not find any particular difference, as regards to clinical aspects. However, our laboratory tests show a recent herpes simplex virus infection in 42% and cytomegalovirus in 11% of cases; moreover we could not find any EBV infection. Our data suggest that viruses other than EBV can play a role in NDPH.

Adolescent↗
PubMed1991

Syncytial giant-cell hepatitis. Sporadic hepatitis with distinctive pathological features, a severe clinical course, and paramyxoviral features.

BACKGROUND AND METHODS: We describe a new form of hepatitis, occurring in 10 patients over a period of six years, characterized clinically by manifestations of severe hepatitis, histologically by large syncytial giant hepatocytes, and ultrastructurally by intracytoplasmic structures consistent with paramyxoviral nucleocapsids. RESULTS: The patients ranged in age from 5 months to 41 years. The tentative clinical diagnosis before biopsy was non-A, non-B hepatitis in five patients and autoimmune chronic active hepatitis in the others. Five patients underwent liver transplantation; the others died. The diagnosis of syncytial giant-cell hepatitis was established pathologically. The liver cords were replaced in all 10 patients by syncytial giant cells with up to 30 nuclei. In 8 of the 10 the cytoplasm contained pleomorphic particles of 150 to 250 microns, filamentous strands, and particles of 14 to 17 nm with peripherally disposed spikes resembling paramyxoviral nucleocapsids. Structures resembling degenerated forms were found in the other two patients. One of two chimpanzees injected with a liver homogenate from the index patient had an increase in the titer of paramyxoviral antibodies, probably an anamnestic reaction to previous paramyxoviral infection, suggesting that a paramyxoviral antigen but not viable virus was present in the liver homogenate. CONCLUSIONS: Although further virologic studies will be required for precise classification, we believe that paramyxoviruses should be considered in patients with severe sporadic hepatitis.

Acute Disease↗
PubMed1993

Microsporidia infection in patients with the human immunodeficiency virus and unexplained cholangitis.

BACKGROUND: Cholangitis in patients with the acquired immunodeficiency syndrome (AIDS) is usually associated with opportunistic infections by cryptosporidium species or cytomegalovirus, but in about a third of cases no opportunistic agent is identified. We suspected some of these cases of biliary disease might be explained by infection with the microsporidia species Enterocytozoon bieneusi, an obligate intracellular protozoan that causes chronic diarrhea in patients infected with the human immunodeficiency virus (HIV). METHODS: We studied eight HIV-infected homosexual men (in either group IV of the classification of the Centers for Disease Control and Prevention or group II, with a CD4 cell count of < or = 10 per cubic millimeter) who were referred because of cholangitis for which no causative agent had been found by standard tests. All the patients underwent abdominal ultrasonography and endoscopic ultrasonography or endoscopic retrograde cholangiopancreatography with collection of bile from the common bile duct. One patient had transhepatic biliary catheterization, and two others had cholecystectomy. Bile samples, duodenal- and liver-biopsy specimens, and gallbladder tissue were studied by light and electron microscopy. RESULTS: All eight patients with unexplained AIDS-related cholangitis had biliary microsporidosis. Intraepithelial E. bieneusi spores (1 to 2 microns) and supranuclear plasmodia (3 to 8 microns) were identified in the six duodenal-biopsy specimens. May-Grünwald-Giemsa staining of bile samples revealed free forms of microsporidia in all eight patients, and the presence of E. bieneusi was confirmed by electron microscopy. E. bieneusi was also identified in ductal biliary cells on a liver biopsy, in one common-bile-duct smear, and in gallbladder epithelium (in two patients). Four patients were found to have associated but previously undetected biliary or duodenal cryptosporidiosis, whereas another had biliary infection associated with cytomegalovirus. CONCLUSIONS: Infection of the biliary tract with E. bieneusi is associated with and may be a cause of AIDS-related cholangitis.

AIDS-Related Opportunistic Infections↗
PubMed2002

Characterization of avian metapneumoviruses isolated in the USA.

Avian pneumovirus (APV; officially known as turkey rhinotracheitis virus) is an emergent pathogen of birds in the USA that results in upper respiratory tract disease in turkeys. Six years after the first outbreak in the USA, the disease continues to ravage turkey flocks, primarily in the state of Minnesota. From 1997 to 2000, the industry recorded losses estimated at 15 million US dollars per annum. Researchers have developed sensitive diagnostic techniques, including the enzyme-linked immunosorbent assay and the reverse transcriptase-polymerase chain reaction. which, when used together, are highly sensitive in detecting APV outbreaks in commercial turkey flocks. Phylogenetic analysis of the nucleotide and predicted amino acid sequence of 15 US viruses isolated between 1996 and 2000 demonstrated that the US viruses are relatively homogenous but different from the European APV subgroups A and B, resulting in the classification of US isolates into subgroup C. Infectious APV was isolated from sentinel waterfowls placed close to an infected commercial turkey farm and from wild Canada geese captured in Minnesota, suggesting that free-ranging birds may be involved in the spread of APV. Current efforts to prevent and control the infection include improving management and biosecurity practices and developing attenuated live and deletion mutant vaccines capable of conferring protection.

Animals↗
PubMed1994

The renin-angiotensin-aldosterone system and vasopressin in early-stage liver cirrhosis after HBV infection in children.

We evaluated the dynamic response of renin, aldosterone, and vasopressin to intravenous water loading (20 ml 5% glucose/kg b.w.) in 12 children (aged 7-18 years) with postinflammatory liver cirrhosis after hepatitis B virus (HBV) infection. All of the patients had early-stage liver cirrhosis; according to Child's classification, nine patients had group A; three, group B cirrhosis. A group of 17 children with chronic persistent hepatitis served as the control. The diagnoses were confirmed in all of the patients by liver biopsy. The patients followed a diet containing 3 mmol NaCl/kg/day, maximum 100 mmol per day for 6 days. Water loading was performed in recumbency over approximately 45 min. Renin, aldosterone, and vasopressin, assayed by radioimmunoassay (RIA), were determined before, 1 h, and 5 h after starting the water load. Prestudy hormone levels were within normal range in both groups. Renin and aldosterone concentration change patterns were similar in both groups and characterized by suppression of hormone activity caused by central volume expansion and recovery to prestudy levels after 5 h. However, the pattern of change of vasopressin concentrations differed in the control and study groups. In contrast to that of the controls, volume expansion did not suppress vasopressin in the group with liver cirrhosis. We conclude that failure to suppress vasopressin activity after central volume expansion may be one of the early mechanisms responsible for water-electrolyte imbalance in liver cirrhosis in children.

Adolescent↗
PubMed2001

The role of infectious agents in pulmonary and systemic vascular disease.

With emphasis on the pulmonary circulation, three general types of vascular disease are discussed: fibroproliferative (atherosclerosis), cellular proliferative (endothelial neoplasms) and inflammatory (granulomatous vasculitis). The causes of these phenotypic responses are invariably multifactorial, but infectious agents including viruses, Chlamydia, Helicobacter, Rickettsia, mycobacteria and other infectious agents have been increasingly implicated in the pathophysiology. The classifications of vascular diseases are complicated and confusing and many eponymous diseases are specific variations of more general disease processes. The pivotal role of the monocyte/macrophage and T-cells is discussed, particularly with regard to intracellular infections. In addition to antimicrobial therapy, modifications of macrophage function by IFN-gamma and blockade of TNF are attractive areas for therapeutic research. Diseases with many synergistic causes will probably also require multifaceted therapeutic interventions.

Animals↗
PubMed2003

Candida esophagitis: risk factors in non-HIV population in Pakistan.

AIM: Candida esophagitis is a frequent infection in immunocompromised patients. This study was designed to determine its characteristics in non- human immune deficiency virus (HIV) infected patients attending a teaching hospital. METHODS: Clinical records of all patients coded by international classification of diseases 9th revision with clinical modifications' (ICD-9-CM), with candida esophagitis diagnosed by esophagogastroduodenoscopy (EGD) and histopathology over a period of 5 years were studied. RESULTS: Fifty-one patients (27 males, 24 females, range 21-77 years old and mean age 52.9 years) fulfilled the criteria (0.34% of the EGD). The common predisposing factors were carcinoma (OR 3.87, CI 1.00-14.99) and diabetes mellitus (OR 4.39, CI 1.34-14.42). The frequent clinical symptoms were retrosternal discomfort, dysphagia and epigastric abdominal pain with endoscopic appearance of scattered mucosal plaques. Another endoscopic lesion was associated with candida esophagitis in 15% patients. CONCLUSION: Carcinomas, diabetes mellitus, corticosteroid and antibiotic therapy are major risk factors for candida esophagitis in Pakistan. It is an easily managed complication that responds to treatment with nystatin.

Adult↗
PubMed1976

[Behavior of specific antibodies against hepatitis B surface antigen in children with acute and chronic hepatitides in healthy carriers and in various co-habitants of chronic hepatitis patients].

The Authors studied the behaviour of ABsAb in a pediatric case-list made up of 8 cases of virus B acute hepatitis, and 63 cases of chronic hepatitis in different evolutive phases: besides, this investigation was extended to 48 healthy carriers (29 of whom bioptically confirmed) and 35 cases of cohabitants with HBsAg-positive hepatic chronic patients. In acute hepatitis the antibody pattern, even if delayed in time, mimics the modalities of the organic response against exogenous stimulations, therefore it constitutes an index of past disease and recovery. In chronic hepatitis (both HBsAg-positive and negative) the specific antibody to the surface antigen is present only at a low percentage (27%) and generally at low titres. In healthy carriers, bioptically ascertained, it is practically absent as to suggest more careful consideration when it turns out present (pseudo-carriers?), while in the cohabitants with virus B patients, especially if chronic, along with HBsAg detection, it consitutes an indispensable element for their classification in patients, ex-patients, not infected and healthy carriers. A very interesting finding, requiring further confirmation, is the unusual behaviour of these antibodies in some cases of relapsed chronic hepatitis.

Acute Disease↗
PubMedDate not supplied

[Morphological and immunohistochemical characteristics of primary brain lymphomas in AIDS patients].

Primary lymphomas of the brain were studied in 6 AIDS patients. The lymphomas were characterized by multicentricity, extended necroses and location in large hemispheres. Two types of tumor cell growth were recorded: diffuse and perivascular with vascular wall destruction. According to the International Histologic Classification (2001), these lymphomas were classified as diffuse B-cell large cell lymphomas subdivided into 3 variants: immunoblastic with plasma cell differentiation, centroblastic polymorphic and large cell anaplastic (by Kils classification criteria). Immunohistochemically (LMP-1) and by hybridization in situ (RNA EBER-1,2) Epstein-Barr virus was found in tumor cells from all the patients. In 5 of 6 cases studied expression of the antiapoptotic protein bcl-2 and in 2 cases expression of mutant p53 were revealed.

Adult↗
PubMed2004

Probing Norwalk-like virus presence in shellfish, using artificial neural networks.

A database was examined using artificial neural network (ANN) models to investigate the efficacy of predicting PCR-identified Norwalk-like virus presence and absence in shellfish. The relative importance of variables in the model and the predictive power obtained by application of ANN modelling methods were compared with previously developed logistic regression models. In addition, two country-specific datasets were analysed separately with ANN models to determine if the relative importance of the input variables was similar for geographically diverse regions. The results of this analysis found that ANN models predicted Norwalk-like virus presence and absence in shellfish with equivalent, and better, precision than logistic regression models. For overall classification performance, ANN modelling had a rate of 93%, vs 75% for the logistic regression. ANN models were able to illuminate the site-specific relationships between indicators and pathogens.

Databases, Factual↗
PubMed2003

[Investigation of Arboviruses in Lancang river down-stream area in Yunnan province].

OBJECTIVE: To investigate the epidemic state of arboviruses in the downstream area of Lancang river in Yunnan province. METHODS: Mosquitoes were collected from Lancang river downstream area (including Lancang county and Simao city) during summer in 1998 and stored in liquid nitrogen after classification. The mosquito pools were homogenized and centrifuged, then the supernatant was inoculated into C6/36 cells for virus isolation. New isolates were identified by neutralization test(NT), ELISA, immunofluorescence assay(IFA) and polyacrylamid gel electrophoresis(PAGE). RESULTS: Totally 22 isolates of arbovirus were obtained from 233 mosquito pools by inoculation of C6/36 cells and positive rate of the isolation was 9.4%. Ten strains were resistant to both ether and 5 prime-IDU. So they were non-enveloped double-stranded (ds) RNA virus. Twelve segmented RNAs were shown by PAGE and PAGE profiles from the ten strains were 6-6 with minor variation. The isolates can be neutralized by immunized mouse ascites fluid of BJ95-75 strains of coltivirus by NT, and reacted with monoclonal antibody against BJ95-75 by ELISA. These viruses were identified as coltivirus. Nine isolates were sensitive to ether and resistant to 5 prime-IDU. So they were non-enveloped RNA viruses. PAGE showed 10 segmented RNA, and they were identified to be orbiviruses. Three isolations were sensitive to ether. One of them can be neutralized with JEV A2 strain antibody by NT and was positive to the homologous antibody by IFA. It was identified being strain of JE virus. One strain(YN92-4) can be reacted with anti-bunyavirus group specific immune ascites fluid by both IFA and ElISA, but reacted neither with anti-alpha virus group, nor with anti-flavivirus group JE virus ascites fluid. The virions are spherical and about 87 nm in diameter with surface projections by negative staining. Conclusion Twenty-two isolates have been obtained from wild caught-mosquitoes of Lancang river down-stream area in Yunnan province. Among them ten, nine, one and one were identified as coltivirus, orbivirus, JE virus and bunyavirus, respectively. One is under identification. This is the first report on bunyavirus isolated from mosquitoes in China.

Animals↗
PubMed1994

[Bacterial infection in patients with HIV infection].

A variety of bacterial infections occurred in patients with human immunodeficiency virus (HIV) infection and the supposed mechanisms of their complications were reviewed, especially according to the revised classification system for HIV infection. Among the reported cases of AIDS autopsy in Japan, only 33% of the cases were noticed with bacterial infections. This observation, however, represented that many doctors had not paid an attention to bacterial infections in patients with HIV infection. Bacterial infections were also important for the patient's survival as well as the diagnosis of AIDS.

AIDS-Related Opportunistic Infections↗
PubMed1979

A further member of the Yucaipa group isolated from the common wren (Troglodytes troglodytes).

In 1977, 477 small birds of 52 species were virologically examined. Five cloacal swabs from Troglodytes troglodytes yielded two paramyxovirus strains which were found antigenically related to, but not identical with Ch/Yucaipa/California/56 virus according to three serological tests. The ecological significance of these findings and the possibility of paramyxovirus classification into four types are discussed.

Animals↗
PubMedDate not supplied

[Magnesium deficiency in patients with HIV-AIDS].

The serum magnesium concentrations are compared between the three clinical classification categories established in 1993 by the Centers for Disease Control (CDC) (infection) by the human immunodeficiency virus) in adults, and its relation with the CD4 lymphocyte count, albumin, and pre-albumin. The serum magnesium concentration is part of the broad analytical screening and it is determined by atomic absorption spectroscopy. The data obtained were analyzed by the statistical program SPSS. The comparisons of the serum magnesium concentrations between the three clinical categories of the CDC were evaluated by an analysis of variance (ANOVA test). Afterwards, and using a regression analysis, the relations between the different variables were evaluated. 35 patients affected by HIV-AIDS were studied, 22 belonging to category A, 3 to category B, and 10 to category C, 29.4% of the patients studied presented hypomagnesemia, with an average serum magnesium level of 17.6 +/- 10.3 mg/l. There is a quadratic relation between the serum magnesium level and the number of CD4 lymphocytes in HIV-AIDS patients studied. A larger number of cases would allow us to conclude whether hypomagnesemia is a factor belonging to the disease, as well showing the possible differences in the magnesium state between the three diagnostic groups studied. Future studies will be necessary to clarify the role of magnesium in the clinical progression of patients infected by HIV.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Does previous hepatitis A infection affect the clinicopathological status of chronic hepatitis C?

BACKGROUND/AIMS: The aim of the study was to evaluate the effect of previous infection with hepatitis A virus on histopathological and biochemical changes in chronic hepatitis C. METHODOLOGY: Anti-hepatitis A virus antibodies, liver histopathology and alanine aminotransferase activity were determined in 82 patients with chronic hepatitis C. The liver biopsy specimen of each patient was examined according to Scheuer's classification to indicate the severity of the inflammatory cell infiltration in the portal/periportal and parenchymal area (grading) in a 0-4 scale and fibrous stage (staging) in a 0-4 scale. RESULTS: The overall prevalence of anti-hepatitis A virus antibodies was 63.1%. Anti-HAV-positive patients were significantly older than anti-HAV-negative ones (mean age 42.5 and 33.1 years respectively, p < 0.05). After stratifying the study sample into two age groups (< 40 years and > or = 40 years) the percentage of anti-HAV-positive individuals was similar irrespective of grading, staging score or presence of steatosis. No remarkable differences were observed between the anti-HAV-positive and -negative group in the mean ALT activity. CONCLUSIONS: The results of our study indicate that previous hepatitis A is not associated with progressive course of chronic hepatitis C.

Disease Progression↗
PubMed1993

Cell-to-cell movement of plant viruses. Insights from amino acid sequence comparisons of movement proteins and from analogies with cellular transport systems.

Cell-to-cell movement is a crucial step in plant virus infection. In many viruses, the movement function is secured by specific virus-encoded proteins. Amino acid sequence comparisons of these proteins revealed a vast superfamily containing a conserved sequence motif that may comprise a hydrophobic interaction domain. This superfamily combines proteins of viruses belonging to all principal groups of positive-strand RNA viruses, as well as single-stranded DNA containing geminiviruses, double-stranded DNA-containing pararetroviruses (caulimoviruses and badnaviruses), and tospoviruses that have negative-strand RNA genomes with two ambisense segments. In several groups of positive-strand RNA viruses, the movement function is provided by the proteins encoded by the so-called triple gene block including two putative small membrane-associated proteins and a putative RNA helicase. A distinct type of movement proteins with very high content of proline is found in tymoviruses. It is concluded that classification of movement proteins based on comparison of their amino acid sequences does not correlate with the type of genome nucleic acid or with grouping of viruses based on phylogenetic analysis of replicative proteins or with the virus host range. Recombination between unrelated or distantly related viruses could have played a major role in the evolution of the movement function. Limited sequence similarities were observed between i) movement proteins of dianthoviruses and the MIP family of cellular integral membrane proteins, and ii) between movement proteins of bromoviruses and cucumoviruses and M1 protein of influenza viruses which is involved in nuclear export of viral ribonucleoproteins. It is hypothesized that all movement proteins of plant viruses may mediate hydrophobic interactions between viral and cellular macromolecules.

Amino Acid Sequence↗