G. Tovey

Diarrhoea associated with cyanobacterium-like bodies: a new coccidian enteritis of man

Faecal excretion of cysts known as cyanobacterium-like bodies (CLB) is associated with a diarrhoeal illness, which is often prolonged and severe. It is seen mainly in travellers and immunocompromised patients. Recently these cysts have been shown to be coccidian oocysts. We describe three patients who developed diarrhoea while travelling abroad. Stool samples from all three patients contained CLB. Jejunal aspirates from two patients also yielded CLB. Conventional histology of jejunal biopsy specimens confirmed that two patients had enteritis. Electronmicroscopy of the same biopsy specimens revealed intraepithelial coccidia. These findings suggest that the small bowel is the site of infection of this new coccidian disease.

Application of electron microscopy to the study of structural changes in the liver in non-A, non-B hepatitis

Ultrastructural studies employing techniques such as alternative electron metal stain, high-angle tilting and high-voltage electron microscopy were carried out on liver biopsies obtained from chimpanzees infected with non-A, non-B hepatitis. Typical derangement of the endoplasmic reticulum leading to the formation of tubular structures in hepatocytes was observed. The use of potassium permanganate as an alternative stain revealed two features which have not been previously described. The first of these shows the wall of the tubular structures to be composed of a well-defined fibrillar-like meshwork with a periodicity of approximately 15 nm. The second feature is the demonstration of clusters of fibrin-like inclusions consisting of striated fibrils in the neighborhood of the tubular structures. The presence of intracytoplasmic fibrin may indicate non-specific morphological evidence of cell injury. Crystalline structures containing arrays of particles with an average size of 24 nm were also observed in the endoplasmic reticulum of endothelial cells of the hepatic sinusoids. Morphological differences between the crystalline lattice and the reticular arrangement, demonstrated with the use of high-angle tilting of the specimen in the electron microscopy suggest that the arrays may not be viral particules but a reflection of pathological response of the host cell.

Fulminant hepatitis: An ultrastructural study

Ultrastructural changes were observed in 23 consecutive patients who died from fulminant hepatic failure due to hepatitis B virus (4 cases), sporadic non-A, non-B (7), or paracetamol (acetaminophen) overdose (12) and in 3 patients with subacute hepatic necrosis of unknown cause. The findings are described in detail in 12 of these patients. Fatal fulminant hepatitis was characterised by massive confluent necrosis accompanied by collapse of reticulin framework and sudden drop-out of liver cells. No aetiological distinction could be made between different viral causes of fulminant hepatitis on the basis of ultrastructural pathology. Parenchymal changes in viral cases varied from reversible non-specific necrosis to irreversible changes where fragmentation of endoplasmic reticulum, mitochondria and nuclei had occurred. Differences in ultrastructural pathology between non-viral (paracetamol overdose-induced) and viral fulminant hepatitis were apparent. Modification of endoplasmic reticulum with enlarged attached polyribosomes, breakdown of plasma membrane, accumulation of cytoplasmic amorphous material and karyorrhexis and karyolysis of nuclei were the most prominent features in non-viral cases.

A new method for detecting hepatitis B surface antigen in liver by silver staining

Staining of tubular and circular structures within the cisternae of the endoplasmic reticulum of the cytoplasm of liver cells infected with hepatitis B virus was enhanced by the use of 1% aqueous silver proteinate.