Histopathological and ultrastructural studies of a mouse lung model of Campylobacter jejuni infection.

Campylobacter jejuni is a major cause of diarrhoea in humans. However, the pathogenesis of C. jejuni diarrhoea is poorly understood due to the lack of a good animal model of infection. Many animals have been tried with limited success, but a mouse lung model of infection has been found to be satisfactory previously; however, the lung pathology of this model has not been studied. For the purpose of characterizing the histopathological and ultrastructural lesions in the lung of the mouse pulmonary model of C. jejuni infection, C. jejuni strain 81-176 or sterile PBS was intranasally inoculated into BALB/c mice. The infection resulted in a mild illness only, and in an initial predominance of polymorphonuclear cells, followed by the accumulation of macrophages and later the prominence of epithelioid cells. Focal peribronchial pneumonia appeared on day 3, granuloma-like reaction on day 4 and bronchopneumonia on day 5 post-infection. These features developed until day 5 post-infection, but were less consistent afterwards when histopathology was monitored up to 9 days post-infection. Intracellular structures resembling bacteria were observed on days 3 and 5 post-infection, but not on day 7 post-infection. On days 3 and 5 post-infection, degenerative changes were also observed by transmission electron microscopy. The histological changes were not associated with acid-fast bacteria or any fungal elements. The infection was systemic as C. jejuni was isolated from blood and all organ homogenates (lung, spleen, liver, and small and large intestines) at 24 h post-infection. Thereafter, the organism was recovered from the intestine only, thus indicating its predilection for this location. This characterization of pathology should contribute to a better understanding of the animal model and pathogenesis of C. jejuni infection.

Scanning electron microscopic observations on the third ventricular floor of the rat following cervical sympathectomy.

Various investigators have shown that unilateral ganglionectomy or transection of the internal and external carotid nerves leads to a regenerative response in the ipsilateral superior cervical ganglion and to uninjured mature sympathetic neurons sprouting into bilaterally innervated shared target organs. In this study changes in the supraependymal neuronal network following unilateral and bilateral cervical sympathectomy on the infundibular floor of the third ventricle were studied by scanning electron microscopy in comparison with normal and sham-operated control animals. After unilateral cervical sympathectomy there was a great increase in the number of varicose nerve fibres on the infundibular floor as compared to the normal and sham-operated control animals. Not only was there an increase in the number of nerve fibres, but also their varicosities were substantially larger than those normally present on the ependymal surface. This study indicates the possible sympathetic projections from the superior cervical ganglia to the ependymal surface of the third cerebral ventricle.

Ultrastructral studies on the tegument of Dicrocoelium dendriticum (Rudolphi, 1819) Looss 1899.

The tegument of Dicrocoelium dendriticum was studied by scanning and transmission electron microscopy. It consists of an anucleate surface syncytium and a deeper nucleated zone. The syncytial layer covers the entire surface of the fluke. It is connected to the nucleated zone through thin cytoplasmic strands. The syncytium is bounded by an apical plasma membrane which is highly folded. This layer mainly contains abundant mitochondria of varying size and shape, and two types of granules, dumbbell shaped and spherical. Although the apical surface shows active exocytosis, no evidence for endocytosis is observed. This is the first study from the State of Kuwait showing the presence of this liver fluke in sheep imported from other countries.

Antioxidant enzyme level in the testes of cirrhotic rats.

OBJECTIVES: An understanding of the tissue and organ level of antioxidant enzymes that scavenge reactive oxygen species may provide an indication of their susceptibility to free radical-related cytotoxic damage. A direct association between testicular production of excessive reactive oxygen species and male infertility has been noted. We measured the activities of superoxide dismutase and glutathione peroxidase in the testes of thioacetamide-induced cirrhotic rats. METHODS: Antioxidant enzyme activities and trace element levels (copper, zinc, manganese, and selenium) in the testes of thioacetamide-induced cirrhotic and control rats were measured. The statistical difference between the experimental and control groups with regard to the activities of superoxide dismutase and glutathione peroxidase and levels of trace elements was analyzed with Student's t test. RESULTS: Our results showed a significant decrease in the activity of these enzymes in the testes of cirrhotic rats. The testicular levels of copper, zinc, and manganese, which are associated with these antioxidant enzymes, increased, whereas selenium decreased slightly in cirrhotic rats; that decrease was not statistically significant. CONCLUSIONS: Our studies showed a drastic decrease in the level of antioxidant enzymes in the testes of cirrhotic rats that could have deleterious effects on sperm function in these animals. Further studies are necessary to understand the exact pathways of trace element metabolism in the testes of cirrhotic rats.