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Biomedical subjects

J C Booth

Publications and source records attributed to J C Booth.

At least 37 records · Page 2Linked to original sources

Lymphocyte responses to human cytomegalovirus in different groups of patients in Britain and in adults from west Africa and the Middle East.

Antibody prevalence and lymphocyte proliferation responses to cytomegalovirus (CMV) and herpes simplex virus (HSV) were compared in several different groups of patients: genitourinary medical (GUM) patients, hemophiliacs, men with clinical acquired immunodeficiency syndrome (AIDS) and cases of primary CMV mononucleosis, and also in adults in the general population (control subjects) comprising separate groups native to Britain, West Africa, and the Middle East. Among the British control subjects who were positive for CMV IgG, all were also positive against CMV antigen by the lymphocyte transformation test (LTT). However, among those who were CMV IgG-positive in the various groups of patients, 20-86.9% gave positive responses to CMV antigen by the LTT; moreover, 75.7% and 55.5% of the CMV IgG-positive healthy control subjects from West Africa and the Middle East, respectively, gave positive LTT responses to CMV antigen. When the same groups of patients were tested for responsiveness to HSV antigen by the LTT, there was good agreement between a positive result by this test and by serology in all except those with primary CMV mononucleosis (42.8%). Overall, lymphocyte responses to CMV were significantly impaired in healthy, CMV antibody-positive subjects from West Africa and the Middle East compared to similar subjects from Britain.

Adult↗

Human cytomegalovirus and acute rejection after heart transplantation are not directly associated.

Retrospective and prospective analyses of heart transplant recipients showed no significant association between acute rejection and the detection of cytomegalovirus (CMV) infection by culture or the polymerase chain reaction (PCR) for viral DNA, neither on grounds of the incidence of both conditions nor in relation to which was diagnosed first in the patient. Semiquantitative PCR of serial blood and endomyocardial biopsy specimens from individual patients revealed different patterns in the development of the viral DNA in the blood and the heart, also clear episodes of CMV infection in CMV antibody-negative recipients of hearts from CMV antibody-negative donors, none of whom went on to develop a CMV-specific antibody response. None of these findings was associated with the development of rejection in the patient. On the other hand, in those patients who did experience rejection, peak levels of CMV DNA in the blood and the heart were usually not reached until 6 weeks or more after transplantation, whereas in those in whom rejection was not detected at all during the period of observation, peak levels of CMV DNA were detected earlier, mainly within the first 6 weeks after transplantation. In several cases, the delayed increase in CMV DNA in those with rejection, albeit not the delay itself, was linked to treatment with steroids. These findings support the view that CMV infection and rejection are independent events, but that the timing of the infection, and whether or not rejection is detected, are indicative of the general status of the immune response in individual patients.

Cytomegalovirus↗

A polymerase chain reaction to detect a spliced late transcript of human cytomegalovirus in the blood of bone marrow transplant recipients.

A reverse transcription (RT) nested polymerase chain reaction (PCR) procedure is described for detecting RNA to a spliced late gene (SLG) of human cytomegalovirus (CMV), the product of which (175 bp) is easily differentiated in agarose gels from the product when the target is unspliced viral RNA or DNA (258 bp). The SLG-RT-PCR has been compared against a semi-quantitative PCR for CMV DNA in buffy-coat specimens collected weekly after bone marrow transplantation from 3 patients and against the results of culturing these specimens for CMV both by conventional virus isolation, based on the detection of cytopathic effect, and by the early detection of infected cells by staining with virus-specific monoclonal antibodies. The detection of CMV RNA by SLG-RT-PCR correlated well with the detection of infective virus but only when the results of both culture methods were combined, in that neither culture method alone was as sensitive as the SLG-RT-PCR. The presence of SLG RNA in the circulation is of value as a marker of active CMV infection.

Base Sequence↗

Pathogenesis of chronic hepatitis C and associated clinical manifestations.

In 20% of patients exposed to hepatitis C virus, infection is transient but, after a few months, the patient remains susceptible to infection with the same strain. Protective immunity is short-lived. This suggests that recovery is related to the cellular immune response, which presumably lyses infected cells, and that the need during recovery for a virus-neutralizing anti-envelope response, is transient. In 80% of patients the infection is persistent, and it seems that antigenic variation of the envelope proteins allows the virus to escape neutralization by anti-envelope responses. The fact that this antigenic variation occurs at a much lower rate in agammaglobulinaemic subjects suggests that the major immune pressure producing this variation is humoral. How the virus-infected cells avoid lysis by cytotoxic T cells, which can be demonstrated in small numbers in the infected liver, remains unclear. The recent observation, that HCV infects CD8 lymphocytes, raises the possibility that virus infection of CD8 cells may impair their function and contribute to persistent infection. The mechanisms of production of cryoglobulin and of autoantibody formation are both unclear.

Hepacivirus↗

Rapid progression of HIV disease in children with cytomegalovirus DNAemia.

OBJECTIVE: In HIV-1-infected children, active cytomegalovirus (CMV) infection can cause severe clinical manifestations and accelerate progression of HIV disease. However, sufficient quantities of blood samples may not be available either for culture or detection of CMV DNA or antigens in white blood cells. The aim of this study was to investigate the diagnostic and prognostic significance of detecting CMV DNA in serum samples from HIV-1-infected children. DESIGN: Sera from 55 children (18 boys), aged 2-130 months (mean, 49.8 months), with perinatal HIV-1 infection and clinical manifestations attributable to CMV infection were tested for CMV DNA by nested polymerase chain reaction and for class-specific CMV antibodies [immunoglobulin (Ig) G, IgA, IgM] by enzyme-linked immunosorbent assay. The children were followed up for 2 days to 59 months (mean, 25.5 months). RESULTS: CMV infection was demonstrated in 43 children (74.5%), 18 of whom (42%) were positive for CMV DNA. During the follow-up, 13 children with CMV infection (30.2%) died, including 11 (84.6%) who were positive for CMV DNAemia just before death. Of these children, seven died soon after hospitalization without antiviral treatment, and four died despite therapy with ganciclovir or foscarnet. Post-mortem CMV inclusions were revealed in seven out of eight children who underwent autopsy. The two other children who died also had progressive CMV disease and received ganciclovir until death. In comparison with CMV-seropositive children without CMV DNAemia, children with CMV DNAemia showed significantly shorter mean survival time (42.5 versus 60 months; P < 0.01), lower final CD4+ T-cell count (218 versus 499 x 10(6)/1; P < 0.01) and higher mortality rate (P < 0.0001). CONCLUSIONS: The detection of CMV DNA in serum is of value for diagnosis of active CMV infection in HIV-1-positive children, and CMV DNAemia is a good prognostic indicator of severe outcome of HIV disease.

Antibodies, Viral↗

Activation and deactivation of membrane currents in human fibroblasts following infection with human cytomegalovirus.

The whole cell patch clamp technique was used to study the effects on membrane currents of infection of cultured human embryonic lung (HEL) fibroblasts with human cytomegalovirus (CMV). Four types of membrane currents were found in uninfected HEL cells, namely: Ca(2+)-activated potassium current, inward rectifier potassium current, delayed rectifier potassium current and voltage-dependent CMV. Voltage-dependent sodium current was detected in 30% of uninfected HEL cells whenever they were examined up to 72 h after seeding; however this current had completely disappeared by 18 h after infection with CMV. The delayed rectifier potassium current was detectable in 8% of uninfected HEL cells but, after infection, the proportion of cells expressing this current gradually increased from 20% at 18-24 h post-infection to 100% at 48 h and 72 h. Pharmacological agents known to regulate the activity of ion channels, via cellular secondary messengers, did not alter the frequency at which either current was detected in uninfected and infected cells. Phosphonoformate, an inhibitor of CMV DNA polymerase, caused 95% block of expression of CMV 'late' proteins in infected cells but did not prevent the switching off of the sodium current or the increased expression of the potassium current. The results indicate an association between the expression of CMV 'immediate-early' or 'early' proteins and the down-regulation of the sodium current and up-regulation of the potassium current.

Cells, Cultured↗

Comparison of two immunoassay procedures for detecting enterovirus IgM.

Enteroviruses cause significant illness in man but viral diagnosis is problematic. Enterovirus-specific IgM tests have been developed but due to the difficulties of obtaining reliable control sera the interpretation of assay data remains mainly arbitrary and empirical. The present study was undertaken to assess the reliability of such assays by comparing two tests performed independently in two different laboratories: a mu-capture radioimmunoassay (MACRIA) which utilizes 35S-labelled Coxsackie virus antigens and an enzyme immunoassay (EIA). A feature of the MACRIA was that sera were tested in one large batch whereas the EIA was in routine use in a reference laboratory. The MACRIA was easy to perform but more suitable for research investigations than routine diagnostic use. Similar results were detected in the majority of sera tested in the two assays with 85% concordance achieved on testing 120 sera. Of the 18 discrepant results, 11 were positive by EIA only and 7 by MACRIA only. 89-95% concordance was obtained on testing sera against individual Coxsackie B1-5 serotypes, moreover 52% of the sera positive in MACRIA were reactive against only one viral antigen and the results on certain of the more strongly reactive sera suggested the existence of a measure of type specificity in the MACRIA test. Qualitative differences between the two tests highlighted problems of interpretation in the absence of a gold standard and cautioned against sole reliance on serology for diagnosis of enteroviral infections.

Animals↗

Cytomegalovirus-associated stage 4S neuroblastoma relapsed stage 4.

Neuroblastoma is one of the most frequent solid tumors in childhood, rarely recurrent after five years from diagnosis. Cytomegalovirus (CMV), a major pathogen causing congenital birth defects and severe opportunistic diseases, has been shown to have teratogenic, immunodepressive and oncogenic properties. The case of a girl with stage 4S neuroblastoma diagnosed at three months and relapsed as stage 4 five years later is reported. In both circumstances, active CMV infection was revealed by positive CMV-specific IgM and IgA antibodies, CMV-DNAemia and CMV culture. At three months, the patient presented with subcutaneous nodules, hepatosplenomegaly and increased aminotransferase levels, and the opsolonus-myoclonus syndrome. Mental retardation developed later on. At 5 years, relapsed neuroblastoma was preceded by a mononucleosis-like syndrome concomitant with active CMV infection and decreased levels of immune cells and natural killer activity. Clinical, virologic, and immunologic findings suggest an immune-mediated pathogenic role for CMV in this tumor.

Abdominal Neoplasms↗

The detection of HIV-1 proviral DNA by PCR in clotted blood specimens.

Six hundred and ninety-two specimens, each consisting of a suspension of the residual free cells in samples of clotted blood (but not the clots themselves) from 680 patients at high risk for exposure to human immunodeficiency virus (HIV), were tested by a nested polymerase chain reaction (PCR) procedure which had been optimized to give a sensitivity of detection of one copy of HIV-1 proviral plasmid DNA, and the results were compared to those of testing for antibody to HIV on the same specimens. Fifty-one of the specimens were positive for antibody to HIV and 49 of these were also positive by the PCR; the two samples which gave discordant results were found to be PCR-positive when the test was repeated on DNA extracted from the clots themselves. Two specimens were found to be negative for antibody to HIV but were positive by the PCR (53 positive specimens in all). Direct sequencing of the PCR DNA products confirmed their specificity in all cases and demonstrated that no two patients gave the same predicted amino acid sequence for the V3 loop region. The sequences revealed both European/North American and African motifs at the crown of the V3 loop thus indicating a diversity of HIV strains in the SW Thames Region of South London. The results show that the confirmatory PCR for HIV-1 can be carried out efficiently on the same clotted blood specimens as used for routine HIV serology on patients undergoing diagnostic evaluation.

Africa↗

Fibrosing cholestatic hepatitis in a renal transplant recipient associated with the hepatitis B virus precore mutant.

A patient with evidence of chronic infection with hepatitis B virus (seropositive for hepatitis B surface antigen, and with antibody to hepatitis B e antigen) underwent renal transplantation, which subsequently failed. The patient developed abnormal liver function tests and 8 months after the removal of the transplanted kidney, hepatitis B virus DNA was detected in the serum in the absence of hepatitis B e antigen. Liver biopsy revealed the presence of fibrosing cholestatic hepatitis. Sequence analysis of the serum hepatitis B virus DNA showed the presence of the pre-core mutant. This case shows that fibrosing cholestatic hepatitis can occur outside the setting of liver transplantation, and coincided with the development of the pre-core mutant of hepatitis B virus.

Base Sequence↗

Cytomegalovirus viraemia in HIV infection: association with intercurrent infection.

The aim of this retrospective study was to investigate the clinical significance of cytomegalovirus (CMV) viraemia in HIV-infected subjects (with or without AIDS) who had attended this hospital during a 45 month period. They were reviewed regularly and, when clinically indicated, tested for CMV viraemia. The blood of 105 subjects was cultured for CMV and 34 had at least one episode of CMV viraemia during the review period. The viraemia was present during CMV disease in nine of the 34 positive patients and was the only detectable infection in another two. In the remaining 23 patients, CMV viraemia occurred in association with intercurrent opportunistic infection. Among these 23 patients, the viraemia resolved in 12 after treatment (or natural resolution) of the intercurrent infection and only one of these 12 developed CMV disease (mean review period: 8 months). In another seven patients, CMV viraemia persisted despite treatment (or natural resolution) of the intercurrent infection and four subsequently developed CMV disease (mean review period: 4 months) (P = 0.08, Fisher's exact test). From the remaining four patients, no specimens for CMV culture were obtained after treatment of the intercurrent infection. The CD4 count was higher in the 12 patients in whom there was resolution of the viraemia [mean CD4 60 x 10(6)/l] compared with the seven in whom the viraemia persisted [mean CD4 45 x 10(6)/l]. These findings suggest that in some HIV-positive patients, CMV viraemia was potentiated by intercurrent infection with another micro-organism and that its treatment was sufficient to mitigate the CMV disease.

AIDS-Related Opportunistic Infections↗

Prevalence and distribution of BK virus subtypes in healthy people and immunocompromised patients detected by PCR-restriction enzyme analysis.

BACKGROUND: Four antigenic subtypes of BK virus (BKV) have recently been characterised by both genomic subtyping and serological reactivity. OBJECTIVES: To study the prevalence and distribution of subtypes of BKV in different groups of patients. STUDY DESIGN: Urine specimens were collected from 33 bone marrow transplant (BMT) recipients, from 101 HIV-infected patients, from 15 children aged 2-5 and from 40 pregnant women were tested for BKV DNA by polymerase chain reaction (PCR) and subtyped using a PCR-sequencing (PCR-S) and a modified PCR-restriction enzyme analysis (PCR-RE) methods. RESULTS: BKV DNA was detected in 12/18 (67%) of BMT patients with haematuria and 5/15 (33%) without. Overall BKV DNA was detected in 45% of HIV-infected patients, the prevalence of BKV DNA increased with greater immunosuppression as defined by CD4 cell counts. BKV DNA was detected in urine samples from 27% of children and 47% of pregnant women. Four stable BKV subtypes were detected in these patient groups. Dual infections with more than one subtype were identified in urine samples from HIV-infected patients, children and pregnant women but not in the samples from bone marrow recipients. CONCLUSION: This study has confirmed the high prevalence of BKV infection in immunocompromised patients and suggests that stable BKV subtypes with conserved sequences are circulating in the human population. The techniques of PCR-S and PCR-RE described in this study are sufficiently sensitive for subtyping BKV direct from clinical specimens.

Journal Article↗

Recurrent gastrointestinal bleeding associated with chronic pancreatitis.

A 52 year old man with chronic pancreatitis presented with recurrent upper gastrointestinal bleeding. Gastroscopy was normal, but visceral angiography suggested that there were gastric varices. Despite treatment with propranolol he had further episodes of bleeding and so underwent splenectomy to decompress the gastric varices. When the spleen was removed, however, an inflammatory mass in the head of the pancreas adherent to the posterior gastric wall was noted. Within it the splenic artery was visible and communicated with the gastric lumen through a small opening in the gastric wall. The artery was ligated and the patient has since had no further bleeding. Thus, chronic pancreatitis should be considered as a cause of recurrent upper gastro-intestinal bleeding, especially when gastroscopy is normal.

Chronic Disease↗

Chronic hepatitis C virus infections: predictive value of genotype and level of viraemia on disease progression and response to interferon alpha.

The effects of hepatitis C virus genotype and viraemia on disease outcome in patients with chronic hepatitis C virus infection were studied. Patients infected with genotype 1 tended to develop more severe disease, and to respond less well to interferon (IFN) treatment, but no pretreatment variable successfully predicted either the severity of the disease or the response to IFN. Failure to eliminate the virus during the first three months of therapy, however, predicted a failure to derive long term benefit from the current IFN regime. Hence pretreatment variables cannot be used to determine whether individual patients will respond to IFN, but observations during the first three months of therapy can be used to decide which patients will not respond to prolonged therapy. In these patients consideration should be given to changing the IFN dosing regime or using alternative treatments.

Base Sequence↗

Pseudomembranous colitis following clarithromycin therapy.

OBJECTIVE: To describe the association of clarithromycin, used to treat Helicobacter pylori infection and duodenal ulceration, with pseudomembranous colitis in two patients. SETTING: St Mary's Hospital, London, UK. PATIENTS: Two female patients aged 77 and 78 years, admitted with duodenal ulceration and H. pylori infection. INTERVENTION: Clarithromycin (500 mg three times daily) was administered concurrently with omeprazole (40 mg once daily). OUTCOME MEASURES: After an initial improvement in symptoms both patients experienced persistent Clostridium difficile-associated diarrhoea. CONCLUSIONS: High-dose clarithromycin should be used with caution for the treatment of H. pylori infection associated with gastroduodenal ulceration. The drug may induce antibiotic-associated colitis which can lead to morbidity and mortality, particularly in the elderly.

Aged↗

A prospective case-control study of antibodies to coxsackie B virus in idiopathic dilated cardiomyopathy.

OBJECTIVES: This study was conducted to determine the frequency and significance of Coxsackie B virus-specific immunoglobulin-M (IgM) in patients with idiopathic dilated cardiomyopathy and compare them with the frequency in both unmatched and matched control subjects. BACKGROUND: The principal evidence supporting a pathoetiologic role for Coxsackie B viruses in human dilated cardiomyopathy is derived from retrospective serologic studies. These studies have evaluated patients with end-stage disease and have failed to recognize the importance of assessing both matched and unmatched control subjects. METHODS: In this prospective case-control study, we assessed sera for Coxsackie B virus-specific IgM (serotypes B1 to B5) from 114 patients with dilated cardiomyopathy at diagnosis or referral to our center, 94 healthy unmatched control subjects, 41 healthy matched control subjects from the same general practitioner and 32 members of the patients' own households. RESULTS: A higher frequency of positive Coxsackie B virus IgM was observed in patients with dilated cardiomyopathy than in unmatched control subjects (33% vs. 5%; p = 3 x 10(-7)). In patients with dilated cardiomyopathy, the response was monotypic (84%), commonly against serotypes B2 and B5, and was not associated with any clinical or histologic feature. The frequency of positive virus-specific IgM was similar in patients with dilated cardiomyopathy and their 41 matched community control subjects (46% vs. 27%; p = 0.11) and 32 household contacts (37% vs. 28%; p = 0.59). Control subjects who tested positive for virus-specific IgM tended more commonly to be seropositive than did control seronegative subjects (community control subjects 37% vs. 18%, p = 0.32; household contacts 42% vs. 20%; p = 0.36) and had an identical serotypic response in 4 (33%) of 12 cases. CONCLUSIONS: The frequency of Coxsackie B virus IgM was higher in patients with dilated cardiomyopathy than in unmatched control subjects but was similar in patients and control subjects who shared the same environment, indicating local spread of infection. The reason for the association between Coxsackie B virus IgM and dilated cardiomyopathy and its relevance to pathogenesis remain to be established.

Adult↗