Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A combined reverse transcriptase reaction-polymerase chain reaction (RT-PCR) was developed to achieve the sensitive detection of group B rotaviruses (GBR). Sequences derived from genomic segment 3 of the IDIR (intestinal disease of infant rats) strain of GBR permitted the detection of greater than or equal to 0.08 pg of purified IDIR genomic RNA (4,000 genome copies). Primers complementary to the terminal sequences of gene 11 of GBR strain ADRV (adult diarrhea rotavirus) allowed for the detection of as little as 0.008 pg of purified ADRV genomic RNA. Detection of heterologous strains of GBR was also observed with these primer pairs. IDIR gene 3 primers recognized greater than or equal to 8 pg of RNA from bovine GBR obtained from a variety of geographic locations. RNA from IDIR, but not bovine GBR, strains was detected by means of RT-PCR with ADRV gene 11 primers. Neither set of GBR primers was reactive in RT-PCR with fecal specimens containing group A rotaviruses or fecal specimens from uninfected controls. This RT-PCR assay permits the sensitive and specific detection of a variety of GBR in fecal specimens.
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PMID:Detection of animal and human group B rotaviruses in fecal specimens by polymerase chain reaction. 170 48

Severe progressive immunodeficiency syndrome can be induced experimentally with a molecularly cloned isolate of feline leukemia virus (FeLV-FAIDS). The resultant disease syndrome is characterized by persistent viremia, lymphopenia, progressive weight loss, persistent diarrhea, enteropathy, and opportunistic infections. The onset of clinical immunodeficiency disease is prefigured by the replication of the FeLV-FAIDS variant virus in bone marrow and other tissues. The FeLV-FAIDS system can be used to evaluate antiviral agents which act on steps in the replication cycle which are conserved among retroviruses (e.g. reverse transcriptase, protease, assembly). The persistence and magnitude of viremia serves as a useful parameter in antiviral studies because it can be easily measured, presages the eventual development of immunodeficiency, and provides a convenient indicator of therapeutic efficacy either in preventing de novo FeLV infection or in reversing or ameliorating established infection. We describe here the evaluation of 2',3'-dideoxycytidine (ddC) against FeLV-FAIDS infection - both in vitro in cell culture assay systems and in vivo in cats administered ddC either via intravenous bolus dosage or via controlled release subcutaneous implants. We found that, although controlled release delivery of ddC inhibited de novo FeLV-FAIDS replication and delayed onset of viremia when therapy was discontinued (after 3 weeks), an equivalent incidence and level of viremia were established rapidly in both ddC-treated and control cats. The FeLV model, therefore, can be used to assess rapidly experimental single agent or combined antiviral therapies for persistent retrovirus infection and disease.
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PMID:Feline leukemia virus-induced immunodeficiency syndrome in cats as a model for evaluation of antiretroviral therapy. 254 Jan 9

The human immunodeficiency virus is a member of the lentivirus subfamily of the retrovirus family. Retroviruses are RNA viruses which code for an RNA-dependent DNA polymerase (reverse transcriptase), which transcribes the RNA genome into a DNA provirus which, on integration with the host DNA, directs the synthesis of new virions. The RNA genome consists of a gag gene, which codes for the viral core proteins, a pol gene, which codes for the reverse transcriptase, an env gene, which codes for the glycoproteins of the viral envelope, and several genes (tat, rev, vif, vpr, and nef), that code for regulatory proteins. At each end of the genome are long terminal repeats, that contain regulatory elements for transcription. There are 3 subfamilies of Retroviridae (Oncovirinae, Spumavirinae, and Lentiverinae). The Lentiverinae ("slow viruses") include the bovine immunodeficiency virus (BIV), the feline immunodeficiency virus (FIV), the human immunodeficiency viruses (HIV), and the simian immunodeficiency viruses (SIV). SIV has been isolated from macaques (mac), African green monkeys (agm), sooty mangabeys (sm), and mandrills (mnd). Only SIVmac causes an AIDS-like disease in its natural host, but it is genetically closer to HIV-2 than to HIV-1. SIVsm causes an AIDS-like disease in macaques, but not in the sooty mangabey. Monkeys infected with SIV develop diarrhea, wasting, decrease in T4 lymphocytes, lymphadenopathy, development of giant cells, and encephalitis, as well as opportunistic infections. Kaposi's sarcoma, however, has not been found in SIV-infected primates. Virus is recovered from peripheral blood mononuclear cells and the brain. SIV models are useful for understanding the natural history of primate lentiviruses, for defining the pathogenesis of AIDS, and for developing vaccines. The ideal model would be one in which HIV causes AIDS, but so far only chimpanzees and gibbons have successfully been infected with HIV-1, and although virus, is recovered from peripheral blood mononuclear cells of chimpanzees within 2 weeks of infection, and 2 animals have lost antibodies to the p24 protein, none has so far developed clinical AIDS. Attempts to develop vaccines to immunize chimpanzees are continuing. Nonprimate lentiviruses include the visna virus, the feline immunodeficiency virus, and the bovine immunodeficiency virus. The visna virus infects fibroblasts by fusion of the viral envelope with the plasma membrane of the fibroblast; it infects macrophages by endocytosis. Infected macrophages regulate the production and dissemination of viral particles. The feline immunodeficiency virus infects T-lymphocytes of cats and produces oral, gastrointestinal and respiratory pathology as well as lymphadenopathy and opportunistic infections. Bovine immunodeficiency-like virus causes a generalized lymphadenopathy similar to that seen in AIDS-related complex.
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PMID:Animal models for HIV infection and AIDS: memorandum from a WHO meeting. 285 Jan 18

During the past two decades, the essentiality of zinc for man has been established. Deficiency of zinc in man due to nutritional factors and several diseased states has been recognized. High phytate content of cereal proteins decreases availability of zinc; thus the prevalence of zinc deficiency is likely to be high in a population subsisting mainly on cereal proteins. Alcoholism is known to cause hyperzincuria and thus may play a role in producing zinc deficiency in man. Malabsorption, cirrhosis of the liver, chronic renal disease and other chronically debilitating diseases may similarly induce zinc deficiency in human subjects. A severe deficiency of zinc has recently been recognized to occur in patients with sickle cell anemia and a beneficial effect of zinc therapy in such patients has been reported. Growth retardation, male hypogonadism, skin changes, poor appetite, mental lethargy and delayed wound healing are some of the manifestations of chronically zinc-deficient human subjects. Taste abnormalities, correctable with zinc supplementation, have been observed in uremic subjects. Recently, abnormal dark adaptation related to zinc deficiency in patients with cirrhosis of the liver and sickle cell disease has been reported. In severely zinc-deficient patients, dermatological manifestations, diarrhea, alopecia, mental disturbances and intercurrent infections predominate and if untreated the condition becomes fatal. Zinc deficiency is known to affect testicular functions adversely in man and animals. This effect of zinc is at the end organ level and it appears that zinc is essential for spermatogenesis and testosterone steroidogenesis. Zinc is involved in many biochemical functions. Several zinc metalloenzymes have been recognized in the past decade. Zinc is required for each step of cell cycle in microorganisms and is essential for DNA synthesis. Thymidine kinase, RNA polymerase, DNA-polymerase from various sources and RNA-dependent DNA polymerase from viruses have been shown to be zinc-dependent enzymes. Zinc also regulates the activity of RNase; thus the catabolism of RNA appears to be zinc-dependent. The effect of zinc on protein synthesis may be attributable to its vital role in nucleic acid metabolism. The activities of many zinc-dependent enzymes have been shown to be affected adversely in zinc-deficient tissues. Three enzymes, alkaline phosphatase, carboxypeptidase and thymidine kinase, appear to be most sensitive to zinc restriction in that their activities are affected adversely within three to six days of institution of a zinc-deficient diet to experimental animals.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Zinc deficiency in human subjects. 636 78

In 1987, under the aegis of the governmental campaign against AIDS, military hospitals in Moscow established a department for the diagnosis and treatment of HIV-infected and AIDS patients among the military and their families. Clinical and laboratory examinations showed that 96 people out of 130 examined either were positive for HIV or were suffering from symptoms of AIDS. 77 were military from African countries, 15 from Russia, and 4 were their family members. Out of these 15 patients from Russia, 8 had been infected via sexual intercourse: 1 via homosexual and 7 via heterosexual intercourse. In 10 patients, HIV infection had been diagnosed 1-2 years after being infected, in 3 patients 3-6 years later, and in 2 patients more than 10 years afterwards. Every other patient exhibited symptoms of the second stage of AIDS: persistent generalized lymphadenopathy. 4 patients had lost body weight, 8 patients had prolonged fever, 2 had diarrhea, 4 had various dermatological symptoms, 4 had opportunistic infections, 5 had other infections (viral hepatitis, acute pneumonia, and salmonella), and 3 patients had other ailments (paranephritis, salpingoophoritis, endometritis, purulent otitis). The cases of 3 patients are described in detail. 4 out of 5 patients who were transferred to this special department demonstrated severe inflammatory processes as a consequence of their HIV-infection: paranephritis, pneumonia, purulent cholangitis, and salmonella. All patients also evinced damage to their immune system: the reduction of T-lymphocyte count and T-helper cells and the reduction of the index of T-helper/T-suppressor cells (to 0.31 from the norm of 1.1-2.2). The treatment of AIDS patients consisted of the use of azidothimidine, which inhibits the activity of reverse transcriptase; the stimulation of the immune system by means of timalin (10 mg for 5 days im); and treating secondary fungal infections (up to 8 million IU of nystatin/day, up to 4 million IU of levorin, and up to 200 mg of diflucan).
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PMID:[HIV infection in servicemen (the work experience of a specialized hospital department)]. 757 95

Despite pathophysiologic effects including diarrhea, cholera toxin (CT) is a potent mucosal immunogen and adjuvant. We investigated the influence of CT on T helper (Th)-type 1 (Th1) and Th2 cell-regulated Ag-specific B cell isotype and IgG subclass Ab responses elicited when the toxin was co-administered orally with different protein Ags. When mice were orally immunized with tetanus toxoid (TT) and CT as adjuvant, this regimen induced TT-specific secretory IgA responses in the gastrointestinal tract as well as serum IgG, including IgG1 and IgG2b subclasses, and IgA responses. This oral regimen also induced TT- and CT-B-specific IgE responses. In addition, CT also elicited adjuvant effects for Ag-specific IgG1, IgE, and IgA responses when two other protein Ags, OVA and hen egg white lysozyme, were given by the oral route. Quantitative reverse transcriptase-PCR was performed to assess levels of mRNA for Th1 (IFN-gamma) and Th2 (IL-4) cytokine expression in TT-stimulated CD4+ T cell cultures. Both Peyer's patches and splenic CD4+ T cells expressed markedly increased levels of IL-4-specific message, but did not result in changes in IFN-gamma mRNA expression. To determine whether the route of immunization influenced IgE responses, mice were immunized s.c. with TT and CT as adjuvant. Significant increases in total and TT-specific IgE Abs were induced when CT was co-administered. Taken together, these results show that CT acts as a mucosal adjuvant to enhance Th2-type responses and in particular, the IL-4 produced results in a characteristic Ab isotype pattern associated with this cytokine.
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PMID:Mucosal adjuvant effect of cholera toxin in mice results from induction of T helper 2 (Th2) cells and IL-4. 759 61

Group C rotaviruses cause sporadic cases and outbreaks of acute diarrhea in children and adults in many countries but have never been identified from patients in the United States. Fecal specimens from children with diarrhea who were hospitalized in Providence, Rhode Island, were screened for group C rotaviruses if rotavirus was detected by electron microscopy but the specimens were negative for group A rotavirus by ELISA. Of 16 specimens examined, 3 were positive for group C rotavirus by ELISA using reagents specific to the Cowden strain of porcine group C rotavirus and all 16 were positive using a more sensitive assay: reverse transcriptase-polymerase chain reaction. Group C rotavirus infections occurred primarily among infants in winter in 4 of the 5 years examined and were acquired both in community and nosocomial settings. Future clinical and epidemiologic studies with group C rotavirus will require development of assays that are more sensitive and simpler to perform.
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PMID:First detection of group C rotavirus in fecal specimens of children with diarrhea in the United States. 779 45

The incidence of astrovirus infection in children under 5 years of age hospitalized for acute gastroenteritis in Melbourne, Australia, during 1995 was determined. Astrovirus was detected in 16 fecal specimens by Northern (RNA) dot blot analysis of RNA isolated from feces with an astrovirus-specific cDNA probe. The incidence of astrovirus infection was determined as 4.2% (16 of 378 total samples) compared with rates of 63.2, 3.7, and 4.2% for rotavirus, adenovirus, and all bacterial pathogens, respectively. Astrovirus was detected during the winter season and mainly in infants between 6 and 12 months of age. Serotyping of samples was carried out by reverse transcriptase PCR and direct sequencing of a 348-bp region of the capsid protein gene. Type 1 strains predominated (11 of 13 typeable samples), although type 4 isolates were also detected. Astrovirus was retrospectively identified in 13 fecal samples collected from hospitalized infants between 1980 and 1985 and shown to contain small viruses by electron microscopy. Type 1 isolates were again the most common, although a type 5 strain was also found. Comparative sequence analysis indicated that type 1 astroviruses exhibited up to 7% sequence divergence over a 15-year period; however, all mutations were silent. The incidence of astrovirus reported here indicates that the virus is a significant cause of severe diarrhea in young children. The genetic analysis also provides important molecular epidemiological information relevant to the development of preventative therapies.
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PMID:Annual incidence, serotype distribution, and genetic diversity of human astrovirus isolates from hospitalized children in Melbourne, Australia. 878 82

Human coronaviruses (HCV) OC43 and 229E are the second most frequently isolated agents of common colds, and have also been associated with severe upper respiratory infections in children and with gastroenteritis of unknown etiology, such as infantile necrotizing enterocolitis. While HCV-OC43 and neonatal calf diarrhea coronavirus NCDCV cannot be held responsible for enteric infection in man, serological data suggest the possible existence of a human coronavirus, antigenically related to HCV-OC43 and NCDCV, and responsible for enteric infections. We developed a rapid and sensitive method for the diagnosis of the human respiratory coronavirus infections, and for detecting these viruses in suspect coronavirus infections. This assay entails a reverse transcriptase polymerase chain reaction, followed by Southern blot analysis with a probe specific for the amplification products.
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PMID:DNA probe for the human coronavirus OC43 also detects neonatal calf diarrhea coronavirus (NCDCV). 884 Oct 41

Three hundred and seventy-eight passengers reported gastroenteritis during four cruises in the western Mediterranean on consecutive weeks of 1995. The rate at which cases were reported each day increased on the fourth cruise. The ship's owner commissioned an epidemiological investigation from the PHLS Communicable Disease Surveillance Centre. Cases reported explosive vomiting and diarrhoea, which lasted from 24 hours to five days, and were suggestive of viral gastroenteritis. No food handlers reported illness, but enquiries suggested that some had been ill and treated themselves. No bacterial pathogens were isolated from faecal specimens provided by cases or from water, food, and environmental samples taken from the galley. Small round structured viruses (SRSV) were identified by reverse transcriptase polymerase chain reaction in two faecal specimens and one specimen of vomit from people who became ill during the fourth cruise. SRSV was also identified in one faecal specimen by electron microscopy. Environmental inspection revealed inappropriate food handling, hygiene, and storage. During one 24 hour period no chlorine was detectable in the water. A case control study conducted on the fourth cruise sought details of exposure to various foodstuffs, unbottled water, and various parts of the ship. No significant associations were found between illness and any exposures. The evidence strongly suggested a continuing outbreak of SRSV infection transmitted from person to person. Some passengers remained on board for a second week and could have transmitted their infection to new arrivals. The ship was cleared and disinfected at the end of the fourth cruise in order to interrupt transmission. Fewer than 10 cases presented in each of the fifth and sixth cruises.
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PMID:An outbreak of viral gastroenteritis on a cruise ship. 899 May 76


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