Large Counterpart Research Articles

Gigantic dense bone island of the jaw

The clinical and radiographic features of gigantic dense bone islands of the jaw were reviewed in 21 subjects to better determine the pathogenesis of this condition. Most of the islands were asymptomatic. They showed a striking predilection for occurrence in the premolar to molar region of the mandible. The greatest dimension of gigantic dense bone islands measured on panoramic radiographs ranged from 2.5 to 7.0 cm, and they were most commonly structureless radiopaque areas. None showed bony expansion buccolingually, nor did they displace adjacent teeth or bony anatomic structures. It is concluded that gigantic dense bone island is not a benign bone neoplasm and is perhaps merely a large counterpart of smaller dense bone islands or idiopathic osteosclerosis.

The Co-Operative as a Fringe Firm and the Notion of Self-Exploitation

RICHARD WELFORD LECTURES AT THE Management Centre, University of Bradford, England. This paper recognises that many co-operatives, because of the small size, will be operating in markets populated largely by traditional capitalist firms and seeks to explore the idea that this dominance will force co-operatives into a position of self-exploitation in order to survive. It begins by looking at the operation of small co-operatives as fringe firms in the marketplace and goes on to explore the notion of self-exploitation, examining specifically the argument that it is dominance by capitalist firms which forces co-operatives into this role. Having built up some clear hypotheses, the author examines some empirical evidence and finds no hard evidence to support the view that dominance by a large capitalist counterpart is likely to lead to self-exploitation. He suggests that the acceptance of a discount on earnings taken in exchange for working in a co-operative environment cannot be termed self-exploitation.

Isolation and characterization of two plaque size variants of Theiler's murine encephalomyelitis virus (DA strain).

We have isolated two plaque size variants of Theiler's murine encephalomyelitis virus (TMEV) strain DA. One variant, TMEV-CL (CL), produced large plaques, while the other, TMEV-DS (DS), produced small plaques in L-2 cells. The DS variant yielded a lower titre in BHK cells and had a significantly slower growth rate when compared to CL and DA. In contrast, DS replicated to a higher titre in the central nervous system (CNS) of infected mice than the large plaque counterpart and DA. Furthermore, the DS (but not CL) variant was temperature-sensitive, replicating 130- to 500-fold more at 37 degrees C than at 39 degrees C. Although DS, CL and DA were able to establish persistent CNS infections in mice, only the DS variant and DA induced demyelinating disease in SJL/J mice. Therefore persistence of TMEV in the CNS is not sufficient to produce demyelinating disease. These two variants of the DA strain of TMEV will be useful for study of the viral genetic elements important in the mechanism of virus-induced demyelination.