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G Corbitt

Publications and source records attributed to G Corbitt.

At least 37 records · Page 2Linked to original sources
PubMed1993

Detection of hepatitis C virus RNA in serum, by combining reverse transcription and polymerase chain reaction in one tube.

Reverse transcription of viral RNA into cDNA and its subsequent amplification by polymerase chain reaction (PCR) are generally carried out as two separate reactions. Here we describe a novel method for the detection of HCV RNA in serum combining both steps in one reaction tube using a wax interface to separate the two sets of reactants during initial cDNA synthesis. This enabled optimisation of both reactions, simplified the test and thereby reduced the risk of cross-contamination.

Chemical Phenomena↗
PubMed1991

Sensitive non-isotopic DNA hybridisation assay or immediate-early antigen detection for rapid identification of human cytomegalovirus in urine.

A sensitive non-radioactive DNA hybridisation assay employing digoxigenin-labelled probes was compared with immediate-early antigen detection and conventional virus isolation for the identification of human cytomegalovirus (HCMV) in 249 urine samples. Of 44 specimens yielding HCMV by virus isolation, more were positive by DNA hybridisation (32; 73%) than by immediate-early antigen detection (25; 52%) (P = 0.05). The specificity of the hybridisation assay in 45 apparently falsely positive specimens was supported by detection of HCMV DNA in 40 of these specimens using the polymerase chain reaction. Many urine specimens may thus contain large amounts of non-viable virus or free viral DNA. Evaluation of various protocols for the extraction and denaturation of virus DNA prior to hybridisation showed that proteinase K digestion with phenol/chloroform extraction was the most sensitive and reliable procedure. We conclude that the non-radioactive DNA hybridisation assay described is a potentially valuable routine diagnostic test.

Antigens, Viral↗
PubMed1991

Comparison of ultracentrifugation and polyethylene glycol precipitation for concentration of hepatitis B virus (HBV) DNA for molecular hybridisation tests and the relationship of HBV-DNA to HBe antigen and anti-HBe status.

A 32P-labelled DNA probe was used to examine 50 hepatitis B surface antigen (HBsAg)-positive sera for the presence of hepatitis B virus (HBV) DNA. HBV-DNA was detected in all 21 HBeAg-positive samples, in one out of 21 anti-HBe-positive samples and in three out of eight HBeAg- and anti-HBe-negative samples. The results of this DNA hybridisation test correlated well with HBeAg status and could be used to determine infectivity in HBeAg- and anti-HBe-negative samples. Ultracentrifugation was marginally superior to polyethylene glycol precipitation for concentrating HBV-DNA from serum.

Chemical Precipitation↗
PubMed1990

Comparison of polyethylene glycol precipitation and ultracentrifugation for recovery of cytomegalovirus from urine prior to detection of DNA by dot-blot hybridisation.

Polyethylene glycol (PEG) precipitation provided a useful alternative to ultracentrifugation for recovering cytomegalovirus (CMV) from clinical specimens prior to DNA hybridisation studies. The conditions for use of PEG are described. In a study of 61 urine samples from patients suspected of CMV infection 18 yielded a positive DNA hybridisation result. Fifteen were positive after both concentration procedures, two after PEG precipitation only and one after ultracentrifugation only. The DNA hybridisation results are discussed in the light of the results of virus isolation by cell culture.

Chemical Precipitation↗
PubMed1989

Inhibitory effects of various anticoagulants on the infectivity of human cytomegalovirus.

We assessed the extent to which the anticoagulants heparin, sodium citrate, Alsever's solution and ethylene diamine tetra-acetic acid (EDTA) (at standard low concentration or at high concentration as attained when only a small blood volume was collected into anticoagulant) inhibited the infectivity of human cytomegalovirus (HCMV). All four anticoagulants had minimal effects on cell-associated virus, but heparin at either low or high concentration and EDTA at high concentration reduced the titre of cell-free virus by 10-100 fold. The large inhibitory effects of heparin and EDTA on cell-free virus indicated that sodium citrate or Alsever's solution were preferable as anticoagulants when blood was collected for assay of CMV viraemia by virus isolation.

Anticoagulants↗
PubMed1989

Detection of cytomegalovirus DNA using probes labelled with digoxigenin.

Cloned HindIII restriction fragments of cytomegalovirus (CMV) DNA (strain AD169) were labelled with biotin, digoxigenin or 32P and used as probes to detect CMV DNA. Probes biotinylated by nick translation, random hexanucleotide priming (RHP) or "photobiotin" were able to detect 10-50 pg of homologous DNA. Probes labelled with digoxigenin or 32P by RHP detected 0.1 pg of homologous DNA, and 1-10 CMV-infected fibroblasts. Comparison of digoxigenin- and 32P-labelled probes in a DNA hybridisation assay on 186 urine specimens demonstrated that these probes were of similar sensitivity, detecting CMV DNA in 40 and 41 specimens, respectively. Positive results were obtained using this hybridisation assay with 11 of 14 specimens (79%) yielding CMV by virus isolation, and with 35 other specimens obtained from patients with laboratory evidence of CMV infection or symptoms compatible with CMV disease. Thus digoxigenin-labelled probes may provide an assay that can detect CMV DNA in specimens yielding a negative result by virus isolation.

Biotin↗
PubMed1988

Detection of cytomegalovirus by dot-blot DNA hybridization using probes labelled with 32P by nick translation or random hexanucleotide priming.

A DNA hybridization assay for the detection of human cytomegalovirus (HCMV) DNA was developed using random hexanucleotide-primed 32P-labelled Hind III restriction fragments of HCMV DNA as probes, and compared with a DNA hybridization assay using probes labelled with 32P by nick translation. Nick-translated probes were shown to be able to detect between 1 and 10 pg of homologous DNA or the DNA of 10-50 HCMV-infected fibroblasts. Random hexanucleotide-primed DNA probes lowered these detection limits to 0.1-0.5 pg of homologous DNA or one to five HCMV-infected fibroblasts. An increase in the autoradiographic exposure time from 18 h to 4 days increased the level of detection for homologous DNA or HCMV-infected fibroblast DNA by approximately five-fold. Preliminary screening of 35 urine samples by DNA hybridization using a random hexanucleotide-primed probe correctly identified three samples positive by virus isolation in tissue culture or immediate-early nuclear antigen detection and 29 of 32 samples negative by tissue culture.

Autoradiography↗
PubMed1988

Malignant progression of laryngeal papilloma associated with human papilloma virus type 6 (HPV-6) DNA.

A case of laryngeal squamous papilloma in the early stages of development showed histological features suggestive of virus infection. Five years later positive evidence of HPV-6 infection was obtained at a time when the lesion had developed into a squamous cell carcinoma. It is concluded that this case represents a complete example of the virus to papilloma to carcinoma sequence, and as far as is known, is the first reported case of its kind in the larynx.

Aged↗
PubMed1988

Human papillomavirus (HPV) genotypes associated with laryngeal papilloma.

Biopsy specimens from 14 patients treated for laryngeal papillomatosis were tested for the presence of human papillomavirus (HPV) genome by the technique of DNA-DNA hybridisation. According to the age of initial presentation, cases were subdivided into juvenile (less than 16 years) and adult onset (older than 16 years) groups. Histological investigation confirmed that it was impossible to distinguish the groups on this basis. Molecular virology using both dot blot and Southern transfer techniques showed that 10 cases carried the HPV type 6 genome, three cases HPV type 11, and in one case no HPV DNA was detected. All six adult onset cases carried HPV 6 sequences while the juvenile onset group comprised four HPV 6 and three HPV 11 cases. In the juvenile onset group more females were affected; in the adult onset group more males were affected. Two of the patients shown to have HPV type 11 sequences in their biopsy material were the most resistant to treatment. One of the adult onset cases subsequently developed a squamous cell carcinoma of the larynx in which HPV 6 DNA was detected. As far as we know this is first time that HPV-DNA has been confirmed in laryngeal papilloma undergoing malignant change.

Adult↗
PubMed1987

Comparison of dot-blot DNA hybridisation and immediate early nuclear antigen production in cell culture for the rapid detection of human cytomegalovirus in urine.

The sensitivity and specificity of four modes of two assays, immediate early nuclear antigen detection in cell culture (IENAD) at 24 and 48 h post-infection (p.i.) by immunofluorescence using a murine monoclonal antibody, and dot-blot DNA hybridisation with overnight or prolonged autoradiography using the 32P-labelled HindIII J fragment of human cytomegalovirus (HCMV) DNA as probe, were compared for the rapid detection of HCMV in urine. The sensitivity of IENAD was enhanced by low-speed centrifugation at the time of inoculation. DNA hybridisation with overnight autoradiography was significantly less sensitive than IENAD at 24 h p.i. (P less than 0.001), and even with prolonged autoradiography the hybridisation assay was slower and significantly less sensitive than IENAD at 48 h p.i. (P less than 0.02). The specificity of the two assays was virtually 100%. The sensitivity of DNA hybridisation was thus clearly inferior to that of IENAD.

Antigens, Surface↗
PubMed1985

Viral infections in childhood leukemia.

The importance of viral infections in 150 children receiving therapy for leukemia was studied prospectively by application of comprehensive viral diagnostic procedures. One hundred five viral infections were identified, with herpes simplex virus and varicella-zoster virus being the most common agents. The spectrum of viruses associated with serious illness was wider than that in previous studies, and adenoviruses, parainfluenza viruses, rhinoviruses, and enteroviruses were important causes of morbidity. Viral isolation was the most sensitive diagnostic procedure used because complement fixation serology was falsely negative in two-thirds of cases. The occurrence of viral infection may be a previously overlooked important cause of respiratory tract infection and acute pyrexia of unknown origin. Viral infection rates were highest in patients with acute myeloblastic leukemia, in induction and relapse, and in patients treated with newer chemotherapeutic schedules. Thus, viruses are important pathogens in children with leukemia.

Adolescent↗
PubMed1983

Prolonged excretion of herpesvirus varicellae in a child with acute lymphoblastic leukaemia.

An eight-year-old girl with acute lymphoblastic leukaemia (ALL) in remission presented with varicella. Zoster immune globulin was not given, but treatment with acyclovir was commenced the day after presentation and continued for five days. Many of the original vesicles ulcerated and persisted for periods in excess of three months, finally leaving residual scarring. Further new vesicles appeared at 80 days and 109 days, and virus was again visualised by electron microscopy. Seroconversion was not demonstrated, although the child has in the past responded serologically to other viruses. A series of other infections afflicting the child at about the same time is documented and the possible implications are discussed.

Acyclovir↗
PubMed1978

Cytomegalovirus infection and the Guillain-Barré syndrome.

A fatal case is described of the Guillain-Barré syndrome due to cytomegalovirus infection, which was associated with hepatitis, myocarditis and viral pneumonia. Previous cases, which have usually run a benign course, are reviewed. Attention is drawn to the possible adverse effect of steroid therapy.

Adrenal Cortex Hormones↗