Absence of viral nucleic acids in early and late dilated cardiomyopathy

OBJECTIVE—To investigate whether viral infection acts as a trigger factor for the development of dilated cardiomyopathy in genetically predisposed individuals with a family history of disease.
SETTING—Patients attending the cardiomyopathy unit in a cardiac tertiary referral centre.
DESIGN—Nested polymerase chain reaction (nPCR) was used to determine whether enteroviral, adenoviral, or cytomegaloviral nucleic acids were detectable in the myocardium of 19 asymptomatic relatives of patients with dilated cardiomyopathy; all these relatives had echocardiographic abnormalities thought to represent early disease. Explanted hearts from patients with end stage dilated cardiomyopathy were also studied and were compared with 25 controls (ischaemic heart disease (21), valvar heart disease (2), hypertrophic cardiomyopathy (1), restrictive cardiomyopathy (1)). Myocardial tissue from two fatal cases of culture positive coxsackie myocarditis was used as a positive control.
RESULTS—No viral nucleic acid was detected in any group other than in those with myocarditis. Spiking of random wells with purified recombinant viral nucleic acids confirmed the sensitivity and reproducibility of the assays.
CONCLUSIONS—Myocardial viral infection is not detectable in relatives of patients with dilated cardiomyopathy who are suspected of having early disease. There is no evidence that viruses act as a trigger factor for initiating the dilated cardiomyopathy in these patients.


Keywords: viral infection; dilated cardiomyopathy     

Detection of Borrelia burgdorferi by polymerase chain reaction in synovial membrane, but not in synovial fluid from patients with persisting Lyme arthritis after antibiotic therapy

OBJECTIVES—To identify possible sites of bacterial persistence in patients with treatment resistant Lyme arthritis. It was determined whether Borrelia burgdorferi DNA may be detectable by polymerase chain reaction (PCR) in synovial membrane (SM) when PCR results from synovial fluid (SF) had become negative after antibiotic therapy.
METHODS—Paired SF and SM specimens and urine samples from four patients with ongoing or recurring Lyme arthritis despite previous antibiotic therapy were investigated. A PCR for the detection of B burgdorferi DNA was carried out using primer sets specific for the ospA gene and a p66 gene of B burgdorferi.
RESULTS—In all four cases, PCR with either primer set was negative in SF and urine, but was positive with at least one primer pair in the SM specimens. In all patients arthritis completely resolved after additional antibiotic treatment.
CONCLUSIONS—These data suggest that in patients with treatment resistant Lyme arthritis negative PCR results in SF after antibiotic therapy do not rule out the intraarticular persistence of B burgdorferi DNA. Therefore, in these patients both SF and SM should be analysed for borrelial DNA by PCR as positive results in SM are strongly suggestive of ongoing infection.

Keywords: Lyme arthritis; polymerase chain reaction; synovial membrane; synovial fluid     

Ankylosing spondylitis in West Africans—evidence for a non-HLA-B27 protective effect

OBJECTIVE—To determine the prevalence of ankylosing spondylitis in the Fula ethnic group in The Gambia, and relate the disease prevalence to the B27 frequency and subtype distribution of that population.
METHODS—215 first degree relatives of 48 B27 positive Fula twin pairs, and 900 adult Fula males were screened for ankylosing spondylitis by clinical and, where appropriate, radiographic means. The B27 prevalence was determined by PCR/sequence specific oligonucleotides on finger prick samples from 100 unrelated Fula, and B27 subtype distribution by SSCP on unrelated B27 positive individuals. This data were then compared with the prevalence of ankylosing spondylitis among B27 positive Caucasians.
RESULTS—No case of ankylosing spondylitis was seen. Six per cent of Fula are B27 positive, of which 32% are B*2703 and 68% B*2705. Assuming the penetrance of ankylosing spondylitis in B27 positive Fula is the same as in B27 positive Caucasians, the probability of not observing any cases of ankylosing spondylitis among the Fula examined is remote (P = 6.7 × 10^-6). Similarly, the chance of not seeing any cases among those expected to be either B*2705 or B*2703 was small (P = 3.2 × 10^-4 for B*2705, and P = 0.02 for B*2703).
CONCLUSIONS—The risk of developing ankylosing spondylitis in B27 positive Fula is lower than in B27 positive Caucasians. This is not explained by the B27 subtype distribution among Fula, and suggests the presence of some non-B27 protective factor reducing the prevalence of ankylosing spondylitis in this population.

     

Genomic detection of enteroviruses in the myocardium--studies on animal hearts with coxsackievirus B3 myocarditis and endomyocardial biopsies from patients with myocarditis and dilated cardiomyopathy.

We examined myocardial tissues for the presence of enteroviral RNA in animal models with experimental coxsackievirus B3 myocarditis and in endomyocardial biopsy samples obtained from patients clinically diagnosed as having dilated cardiomyopathy or myocarditis using polymerase chain reaction (PCR) gene amplification with enterovirus-generic primers and/or coxsackievirus B3-specific primers. In animal models, coxsackievirus B3 was detected in myocardial tissues up to 28 days, 56 days and 180 days after inoculation, in C3H/He mice, A/J mice and Syrian golden hamsters, respectively. The viral genomes were identified by in situ hybridization in myocardial cells and some interstitial cells in and around the myocarditic lesions in animals. In human endomyocardial biopsy samples, enteroviral RNA sequences were detected in 8 (32%) out of 25 patients with clinical dilated cardiomyopathy and in 3 (33%) out of 9 patients with clinical myocarditis. The patients showing histologic findings of myocarditis and clinical features resembling dilated cardiomyopathy had a high incidence (83%) of positive PCR result for enteroviral RNA sequences. Additionally, 25% of patients with dilated cardiomyopathy showing no histologic findings of myocarditis had positive PCR result. This study supports a link between viral myocarditis and dilated cardiomyopathy.     

Search for Mycobacterium paratuberculosis DNA in orofacial granulomatosis and oral Crohn's disease tissue by polymerase chain reaction

Background—Although intestinalCrohn's disease has long been suspected to have amycobacterial cause, possible mycobacterial involvement in orofacialgranulomatosis (OFG) and oral lesions of Crohn's disease has not yetbeen investigated.
Aims—As the slow growingMycobacterium paratuberculosis has been implicated in theaetiology of intestinal Crohn's disease, the potential involvement ofthis mycobacterial species in OFG and oral lesions of Crohn's diseasewas investigated.
Patients—To attempt detectionof the organism in OFG and oral Crohn's disease tissue samples, apolymerase chain reaction (PCR) assay was used on archival formalinfixed, paraffin wax embedded oral tissue sections from 30 patients withOFG, seven with Crohn's disease, and 12 normal controls.
Methods—The PCR assay used wasbased on primers targeting the 5' region of the multicopy IS900 DNAinsertion element of the M paratuberculosis genome. Inorder to achieve maximum sensitivity, two rounds of PCR were carriedout and amplicons confirmed by Southern blot hybridisation to adigoxigenin labelled IS900 DNA probe.
Results—None of the OFG andoral lesions of Crohn's disease samples were positive forM paratuberculosis and all normal controls were also negative.
Conclusions—These results suggestthat M paratuberculosis may not be a major aetiologicalagent in OFG or oral Crohn's disease lesions, although the use ofparaffin wax embedded tissue as opposed to fresh tissue as a samplesource could underestimate the true prevalence of the organism.

Keywords:oral Crohn's disease; Mycobacteriumparatuberculosis; orofacial granulomatosis; polymerase chainreaction

     

Vasomotor effects of L- and D-arginine in stenotic atheromatous coronary plaque

OBJECTIVE—To examine the effects of exogenous L- and D-arginine on coronary stenosis vasomotion in relation to stenosis morphology.
DESIGN—Intracoronary infusions of normal saline, L- and D-arginine (50 and 150 µmol/min), and glyceryl trinitrate (250 µg bolus) were given in 24 patients with coronary artery disease and stable angina. Coronary stenoses were classified as smooth or complex (irregular borders). The diameter of the coronary stenoses and their adjacent reference segments was measured by computed quantitative angiography.
RESULTS—During L-arginine infusion a larger proportion of complex stenoses than smooth stenoses dilated by ⩾ 10% (p < 0.01), and the magnitude of dilatation was greater at the site of complex stenoses (p < 0.05). Irrespective of the type of morphology there was a positive correlation (p < 0.01) between the severity of stenoses and the magnitude of vasodilatation to L-arginine. The response to glyceryl trinitrate was similar in the two groups. No significant change was found in either group in response to D-arginine.
CONCLUSIONS—In patients with coronary artery disease, coronary stenoses—particularly those of complex morphology—dilate in response to the administration of L-arginine but not D-arginine. This finding is consistent with partial deficiency of the substrate for nitric oxide synthesis, L-arginine, at the site of complex stenoses.


     

Low frequency of recent parvovirus infection in a population-based cohort of patients with early inflammatory polyarthritis

OBJECTIVE—To determine the contribution of human parvovirus B19 infection in explaining the incidence of early inflammatory polyarthritis (IP) in a population.
SETTING—The Norfolk Arthritis Register (NOAR) is a community-based programme aiming to ascertain all new cases of IP arising in a population that lead to attendance at primary care.
SUBJECTS—147 newly ascertained subjects with IP with a disease duration of less than 16 weeks.
METHODS—Full clinical appraisal of all subjects who were followed up for three years. B19 IgM assayed with a third generation antibody capture enzyme immunoassay.
RESULTS—Only four (2.7%) patients had evidence of recent B19 infection, only one of whom did not satisfy criteria for rheumatoid arthritis (RA).
CONCLUSION—B19 infection does not explain more than a small proportion of either RA or undifferentiated IP cases occurring in the population.

Keywords: rheumatoid arthritis; epidemiology; human parvovirus B19     

Coxsackievirus B3 infection and its mutation in Keshan disease

AIM: To investigate coxsackievirus B(3) infection and its gene mutation in Keshan disease. METHODS: The expression of Coxsackievirus B(3) RNA was detected in autopsy specimens of acute (12 cases), sub-acute (27 cases) and chronic (15 cases) Keshan disease by in situ hybridization. In sub-acute Keshan disease specimens, 3 cases with positive result by in situ hybridization were selected RT-PCR analysis. The DNA segments were then sequenced. RESULTS: Coxsackievirus B(3) RNA was detected in the cytoplasm of myocardiocyte. The positive rate was 83% in acute, 67% in sub-acute and 80% in chronic Keshan disease. In the conservative region of Coxsackievirus B(3) genome, there was a mutation in 234 (C-T) compared to the non-cardiovirulent strain, CVB(3/0). CONCLUSION: Coxsackievirus B(3) RNA can survive and replicate in heart muscle of Keshan disease, which may play an important role in the occurrence of Keshan disease. The possible mechanism of occurrence of Keshan disease is associated with point a mutation in Coxsackievirus B(3) genome.