Tag: muscle biopsies

Amplification and identification of enteroviral sequences in the postviral fatigue syndrome

Abstract:

Evidence from several sources has long suggested that enteroviruses might play a role in the postviral fatigue syndrome (PVFS).

We used the most sensitive molecular virological method available at present, the polymerase chain reaction (PCR) amplification technique, to look for enteroviral copies in peripheral blood leucocytes and muscle from a well-defined group of patients. We demonstrated that our PCR method amplified a sequence common to a wide range of enteroviral serotypes. A highly significant number of the muscle biopsies (53%: P = less than 0.001) from the patients were positive for enteroviral sequences. With regard to the leucocyte samples, 16% in both patient and control were positive.

The PCR results on the peripheral blood leucocytes were in keeping with serological findings, in showing that the level of exposure to enteroviruses seemed to be the same in patients and controls: it was therefore of the greatest interest that patients were 6.7 times more likely to have enteroviral genome in their muscle.

We conclude that persistent enteroviral infection plays a role in the pathogenesis of PVFS, also providing preliminary evidence that severe mitochondrial injury is one of the mechanisms involved.

 

Source: Gow JW, Behan WM. Amplification and identification of enteroviral sequences in the postviral fatigue syndrome. Br Med Bull. 1991 Oct;47(4):872-85. http://www.ncbi.nlm.nih.gov/pubmed/1665380

 

Persistent virus infection of muscle in postviral fatigue syndrome

Abstract:

Nucleic acid was extracted from muscle biopsy samples from a series of highly selected patients suffering from chronic muscle fatiguability following a viral infection (Postviral Fatigue Syndrome: PVFS).

Samples were examined for the presence of enteroviral RNA sequences or Epstein-Barr (EBV) virus DNA sequences by molecular hybridisation as these two agents have been implicated by retrospective serology in the aetiology of PVFS. We found enteroviral RNA in 24% of biopsy samples and EBV DNA in a further 9% of biopsy samples: no biopsy was positive for both enteroviral RNA and EBV DNA.

In addition, in the case of enteroviruses we found that the persisting virus is defective in control of RNA replication as both strands of enteroviral RNA are present in similar amounts: this is unlike the asymmetric synthesis of genomic RNA seen in a productive, cytolytic enterovirus infection. The implications of these data in relation to mechanisms of viral persistence and muscle dysfunction are discussed.

 

Source: Cunningham L, Bowles NE, Archard LC. Persistent virus infection of muscle in postviral fatigue syndrome. Br Med Bull. 1991 Oct;47(4):852-71. http://www.ncbi.nlm.nih.gov/pubmed/1665379

 

Mitochondrial abnormalities in the postviral fatigue syndrome

Abstract:

We have examined the muscle biopsies of 50 patients who had postviral fatigue syndrome (PFS) for from 1 to 17 years. We found mild to severe atrophy of type II fibres in 39 biopsies, with a mild to moderate excess of lipid.

On ultrastructural examination, 35 of these specimens showed branching and fusion of mitochondrial cristae. Mitochondrial degeneration was obvious in 40 of the biopsies with swelling, vacuolation, myelin figures and secondary lysosomes. These abnormalities were in obvious contrast to control biopsies, where even mild changes were rarely detected.

The findings described here provide the first evidence that PFS may be due to a mitochondrial disorder precipitated by a virus infection.

 

Source: Behan WM1, More IA, Behan PO. Mitochondrial abnormalities in the postviral fatigue syndrome. Acta Neuropathol. 1991;83(1):61-5. http://www.ncbi.nlm.nih.gov/pubmed/1792865

 

Persistence of enteroviral RNA in chronic fatigue syndrome is associated with the abnormal production of equal amounts of positive and negative strands of enteroviral RNA

Abstract:

A subgenomic restriction fragment from cDNA prepared from Coxsackie B2 virus (CVB2) RNA was subcloned into a riboprobe vector allowing the production of enteroviral group-specific RNA probes complementary to either the positive (genomic) or negative (template) strand of enteroviral RNA. These riboprobes were used to follow productive infection of cultured cells by CVB2; as expected, positive strand RNA was synthesized in approximately 100-fold excess over negative strand.

RNA was extracted from muscle biopsy samples from patients with chronic fatigue syndrome and probed for the presence of enteroviral RNA. In cases where enteroviral RNA was detected the amounts of positive and negative strands of enteroviral RNA were approximately equal, in contrast to the situation in lytic infection of cultured cells.

This suggests that enterovirus persistence in muscle is due to a defect in control of viral RNA synthesis.

 

Source: Cunningham L, Bowles NE, Lane RJ, Dubowitz V, Archard LC. Persistence of enteroviral RNA in chronic fatigue syndrome is associated with the abnormal production of equal amounts of positive and negative strands of enteroviral RNA. J Gen Virol. 1990 Jun;71 ( Pt 6):1399-402. http://www.ncbi.nlm.nih.gov/pubmed/2161907