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Biomedical subjects

G M Cleator

Publications and source records attributed to G M Cleator.

At least 37 records · Page 2Linked to original sources
PubMed1996

Analysis of an HIV-infected cohort followed for as long as 15 years after seroconversion.

Data from a cohort of 62 HIV-positive individuals with hemophilia or von Willebrands disease infected for a maximum period of 15 years were analyzed. The relation between CD4+ and total lymphocyte counts and their rate of decline was analyzed with respect to age at seroconversion, time of seroconversion, and development of disease and subsequent death. As expected, the CD4+ and total lymphocyte population decline correlated with increased probability of disease and death. The patients fell into two distinct categories with respect to this decline: those whose cell count declined steadily (single slope) and those whose cell count remained steady or decreased very slowly for a variable period and then declined sharply (double slope). Within this cohort, the presence of a double slope appears to indicate a poorer prognosis, as 9 of 18 of the patients who have died showed this pattern, whereas only 6 of 42 of the remaining patients have this pattern even though more than half of this group have CD4+ lymphocyte counts < 0.2 x 10(9)/L. In addition, the ratio of CD4+ lymphocyte count to total lymphocyte count decreased with increasing cumulative frequency of the cumulative incidence of disease and death and the overall probability of death in this cohort was lower than expected, being 30% 12 years after seroconversion.

Adult↗
PubMed1996

Polymerase chain reaction in the investigation of "relapse" following herpes simplex encephalitis.

Five cases of apparent relapse of herpes encephalitis were investigated. All patients recovered after antiviral and corticosteroid therapy. Samples of CSF taken from the patients at intervals through the initial and subsequent encephalitic episode were examined. PCR amplification of a 351 bp sequence from the Herpesvirus simplex (HSV) thymidine kinase gene demonstrated the presence of HSV DNA in CSF taken during the initial encephalitic illness but not during the second encephalitic episode. Intrathecal synthesis of HSV antibody (HSV antibody index > 1.9) was observed in all cases following the first episode, and there appeared to be no significant increase in intrathecal antibody synthesis in the second episode. High levels of CSF myelin basic protein were found during the acute phases of both the initial and the subsequent encephalitic illnesses. These data suggest that at least in our series of five patients, relapse following HSE may not be due to active viral replication.

Adolescent↗
PubMed1996

Multiplex polymerase chain reaction for adenovirus and herpes simplex virus in eye swabs.

Adenoviruses and herpes simplex virus (HSV) can cause clinically indistinguishable episodes of acute eye disease. Adenovirus infection is associated with nosocomial outbreaks and HSV may result in episodes of recurrent ocular inflammation. In a comparison of multiplex PCR for the two viral DNAs and virus isolation in cell culture, identical results were obtained for 18 of 20 specimens (positive for adenovirus in 5, HSV in 5, and negative in 8). One specimen was falsely negative for each viral DNA. Inclusion of human beta-globin primers in the adenovirus-HSV reaction was precluded by a consequential 10--100-fold reduction in sensitivity for the two viral targets and by the failure of beta-globin DNA amplification at the annealing temperature (45 degrees C) required to ensure detection of adenoviruses of serotypes 7 and 11 with the selected adenovirus primers. A single-target beta-globin PCR gave positive results with 19 of the 20 specimens prepared by treatment with proteinase K lysis buffer, indicating the effectiveness of this simple DNA extraction procedure. Nonetheless, the availability of effective antiviral therapy for HSV made monitoring for extraction failure using human primers crucial to avoid false-negative results for HSV DNA. Adenovirus-HSV PCR has considerable potential for the rapid diagnosis of viral eye disease particularly if beta-globin primers can be included in the reaction.

Adenovirus Infections, Human↗
PubMed1996

Detection of herpes simplex virus DNA in donor cornea culture medium by polymerase chain reaction.

AIMS/BACKGROUND: Herpes simplex virus (HSV) may establish latent infection in the cornea and therefore be transmissible by corneal transplantation. Monitoring of donor cornea culture medium was evaluated for HSV infection. METHODS: HSV was sought using virus isolation in cell culture, and its DNA was amplified to detectable levels using the polymerase chain reaction (PCR). RESULTS: Virus isolation in cell culture was negative on neat, cell pellet, and cell free supernatant prepared from the spent culture media of 80 corneas. Three cell pellets (3.8%) were positive for HSV DNA. The PCR positive culture negative results might have reflected latent rather than active HSV infection of the cornea. Post transplant follow up of the three recipients of corneas with HSV PCR positive organ culture media revealed no evidence of HSV induced eye disease or primary graft failure. CONCLUSION: Screening of corneal culture medium for HSV by virus culture or for HSV DNA by PCR could not be recommended.

Aged↗
PubMed1996

The role of laboratory investigation in the diagnosis and management of patients with suspected herpes simplex encephalitis: a consensus report. The EU Concerted Action on Virus Meningitis and Encephalitis.

As effective therapies for the treatment of herpes simplex encephalitis (HSE) have become available, the virology laboratory has acquired a role of primary importance in the early diagnosis and clinical management of this condition. Several studies have shown that the polymerase chain reaction (PCR) of CSF for the detection of herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2) DNA provides a reliable method for determining an aetiological diagnosis of HSE. The use of PCR in combination with the detection of a specific intrathecal antibody response to HSV currently represents the most reliable strategy for the diagnosis and monitoring of the treatment of adult patients with HSE. The use of these techniques has also led to the identification of atypical presentations of HSV infections of the nervous system and permits the investigation of patients who develop a relapse of encephalitic illness after an initial episode of HSE. A strategy for the optimal use of the investigative laboratory in the diagnosis of HSE and subsequent management decisions is described.

Acyclovir↗
PubMed1996

Pulmonary herpes simplex in burns patients.

In this study we aimed to determine the incidence of herpes simplex virus (HSV) in the lungs of burns patients, and its association with the presence of adult respiratory distress syndrome (ARDS) and pneumonia. Haematoxylin and eosin (H&E), and immunohistochemical (IHC) staining for HSV was performed on lung tissue from 54 patients who had died following burn injury and from nine control cases. Polymerase chain reaction (PCR) for HSV deoxyribonucleic acid (DNA) was performed on a subset both of burns cases and controls. No viral inclusions were detected in H&E sections, but 50% of the burns cases were positive for HSV by IHC staining; no control cases were positive. Nuclear and cytoplasmic immunopositivity for HSV was seen in macrophages and epithelial lining cells. HSV was strongly associated with ARDS (p=0.007), but not with pneumonia (p=0.577). The relative risk of HSV infection was higher for cases with ARDS (2.21) than for those with pneumonia (1.26). PCR for HSV DNA was positive in three out of five burns cases, and in one out of five control cases. Immunohistochemical staining is more sensitive for the detection of herpes simplex virus than haematoxylin and eosin staining for detection of viral inclusions. Burns cases have a high incidence of pulmonary herpes simplex virus infection. Polymerase chain reaction results may not be fully representative due to problems of tissue necrosis postmortem. Pulmonary herpes simplex virus is strongly associated with adult respiratory distress syndrome and the two may be causally linked. Early detection and treatment of pulmonary herpes simplex virus in burns patients may reduce pulmonary complications and mortality.

Adolescent↗
PubMed1995

Two different PCR assays to detect enteroviral RNA in CSF samples from patients with acute aseptic meningitis.

Two polymerase chain reaction (RT-PCR) assays were developed to allow rapid detection of enteroviral RNA in cerebrospinal fluid samples (CSF). Primers homologous to the conserved 5' noncoding region of the enterovirus genome were designed. The RT-PCR product size was approximately 500 bp (479 bp for Poliovirus, 500 bp for Coxsackievirus) and was visualized using ethidium bromide-stained gels. Assay 1 utilized Moloney Murine Leukaemia Virus Reverse Transcriptase (MMLV-RTase) for reverse transcription and Taq polymerase for subsequent PCR. Assay 2 utilized a thermoactive DNA polymerase of Thermus thermophilus (rTth enzyme) for both reverse transcription and DNA amplification. In addition, in Assay 2 reverse transcription and PCR were accomplished within the same reaction tube. Both assays detected between 1 and 0.02 TCID50 of prototype strains of Polio and Coxsackie type B viruses propagated in VERO cell and spiked in a pooled preparation of CSF samples from patients with noninfective neurological disorders. However, Assay 1 was 10-fold more sensitive than Assay 2 when applied to the detection of enteroviral RNA in CSF samples from patients with etiologically well characterized acute aseptic meningitis.

Acute Disease↗
PubMed1995

New method for the extraction of viral RNA and DNA from cerebrospinal fluid for use in the polymerase chain reaction assay.

A new, rapid, and simple method for the isolation of either RNA or DNA from cerebrospinal fluid samples for subsequent amplification by specific polymerase chain reaction (PCR) assays is described. The technique involves a single extraction with a guanidinium thiocyanate acid (GuSCN) buffer, and does not require the use of organic solvents. Applied to the recovery of enteroviral RNA, herpes simplex virus (HSV) and Varicella-zoster virus (VZV) DNAs the method has proved to be of equivalent or better efficiency than established methods of nucleic acid separation but is less laborious and time consuming. The simplicity of the procedure permits the processing of large numbers of samples and the use of a single preparative method for either RNA or DNA PCR makes it an attractive method for the routine laboratory.

Cells, Cultured↗
PubMed1995

Adenovirus cross-infection: a continuing problem.

Nosocomial outbreaks of epidemics of adenovirus keratoconjunctivitis are frequently reported even though the simple measures to prevent or limit such occurrences are well documented. There have been two such outbreaks associated with the accident and emergency department (A&E) of a large, urban eye hospital in recent years. In the first--involving at least 200 cases--there was a delay of two months in initiation of control measures, with consequent potentiation and prolongation of the outbreak. The delay resulted because of the time taken for isolation of the virus responsible (adenovirus type 8). In the second outbreak--23 cases--the use of a rapid diagnostic test--adenovirus immune dot-blot (IDBT)--allowed prompt identification of adenovirus and enabled early introduction of control measures. Important to this strategy was the routine surveillance of eye infections in patients attending the A&E. Many clinicians are reluctant to investigate possible ocular adenovirus disease because of the cost and the delay involved in isolation of the virus in cell culture. Adenovirus IDBT provides a rapid and economic alternative (mean time for IDBT reporting five days compared to 33 days for cell culture isolation). Concerns over sensitivity of IDBT (67-84%) vs. culture are now being addressed with molecular biological approaches to diagnosis offering sensitivity close to that achieved by culture (91% vs. culture) but with the added advantage of same day reporting.

Adenoviridae↗
PubMed1994

Corneal donor infection by herpes simplex virus: herpes simplex virus DNA in donor corneas.

Three corneoscleral discs (from two donors) underwent subtotal endothelial loss during routine "long-term" organ culture storage. Laboratory studies of these corneas revealed evidence of herpes simplex virus (HSV) infection. The fellow cornea from one of the donors had been issued for transplant to a patient with keratoconus. Deterioration of the graft was noted 5 days after surgery; the disc was removed at 2 months and was shown to be infected with HSV. In an experiment designed to simulate initial "cleansing" of donor globes, 0.1% polyvinylpyrolidone-iodine protected cells from infection with HSV. It was concluded that the detection of HSV in these corneas could not be explained by external contamination of the ocular surface. Furthermore, culture of conjunctival and pharangeal swabs taken from 47 consecutive donors confirmed that HSV is rarely isolated at or around the time of death. Five pairs of donor corneas destined for use in transplantation were selected at random and investigated for the presence of HSV. HSV DNA was detected by polymerase chain reaction (PCR) in tissue from two of the corneal donors. Sequential stepwise sectioning suggested that HSV DNA when present was distributed in discrete foci within the cornea. These observations suggest that HSV infection may be a cause of severe endothelial loss during corneal organ culture and possibly provide an explanation for some "failures" of corneal grafting.

Adult↗
PubMed1993

Herpes simplex type 1 encephalitis in acquired immunodeficiency syndrome.

A severe acute necrotizing herpes simplex virus type 1 encephalitis, apparently mediated by macrophages or cytokines or both, was seen in a patient with acquired immunodeficiency syndrome. The necrosis had a distribution similar to that seen in immunocompetent subjects. Viral inclusions were abundant and meningeal reaction was minimal, as previously described in one anergic patient.

Acquired Immunodeficiency Syndrome↗
PubMed1993

The role of a rapid diagnostic test (adenovirus immune dot-blot) in the control of an outbreak of adenovirus type 8 keratoconjunctivitis.

Twenty-three patients were involved in an outbreak of adenovirus type 8 infection based at the Manchester Royal Eye Hospital in the spring of 1991. Confirmation of adenovirus infection was by means of the immune dot-blot test (IDBT) and virus culture, the latter, allowing serotype 8 to be identified as the cause. Epidemiological tracing and limited restriction endonuclease analysis of the virus isolated suggest that 15 patients contracted the infection within the Casualty Department following attendance for minor eye trauma, 10 being infected by the same junior doctor. Seven patients presented with an established adenovirus type 8 conjunctivitis at the first hospital visit and the source of their infection could not be identified. Laboratory confirmation of adenoviral involvement took an average of 5 days by IDBT, compared with 33 days by virus culture. Rapid identification of adenovirus by IDBT enabled early institution of control measures thereby limiting the size of the outbreak.

Adenovirus Infections, Human↗
PubMed1991

CSF pretreatment and the diagnosis of herpes encephalitis using the polymerase chain reaction.

A number of techniques for extraction of DNA prior to polymerase chain reaction (PCR) amplification of herpes simplex virus (HSV) DNA in cerebrospinal fluid (CSF) were compared to the use of "native" CSF in the PCR reaction. The results indicate that extraction of DNA (which allows efficient removal of inhibitors of Taq polymerase) is an essential pre-requisite of the PCR detection of CSF HSV DNA.

DNA, Viral↗
PubMed1990

Diagnosis of herpes encephalitis via Southern blotting of cerebrospinal fluid DNA amplified by polymerase chain reaction.

Herpes simplex virus thymidine kinase gene specific polymerase chain reaction (PCR) amplification of DNA extracted from lumbar cerebrospinal fluid (CSF) and Southern blotting (SB) were evaluated as a method for the diagnosis of herpes simplex encephalitis (HSE). Positive PCR-SB results were obtained with CSF samples from 9 of 10 patients (11 of 12 CSF specimens) with proven herpes encephalitis as early as 2 days after onset of neurological illness. Our data support the suggestion that PCR techniques may provide a clinically relevant "non-invasive" method for the diagnosis of HSE.

Base Sequence↗