No abstract

HPV plays a role in the development of a portion of head and neck squamous cell carcinoma (HNSCC), but only limited information on its role in southern Chinese population is available. A multicenter case-control study was conducted. HPV type, viral integration, E6/7 mRNA expression status, and TP53 mutation were determined. A total of 228 HNSCC were recruited including 137 (60.1%) oral SCC, 34 (14.9%) oropharyngeal SCC, 31 (13.6%) laryngeal SCC, 21 (9.2%) hypopharyngeal SCC, and 5 (2.2%) lip and paranasal sinus SCC. High-risk HPV infection was found in 7.5% (17/228) of HNSCC, but only a small proportion of samples had evidence of viral integration (5.3%, 12/228) or E6/7 mRNA expression (4.4%, 10/228). HPV infection with oncogenic phenotype (integration and E6/7 mRNA expression) was significantly more common in oropharyngeal SCC than controls (9/34, 26.5% vs. 0/42, 0.0%, P < 0.001). Smoking showed a significant association with HNSCC, oropharyngeal SCC, and laryngeal SCC. TP53 mutation was associated with HNSCC (P < 0.001). Older age, TP53 mutation, and HPV16 infection with oncogenic phenotypes were independently associated factors for HNSCC with odds ratios of 1.03 (1.02-1.05), 3.38 (1.71-6.66), and 9.19 (1.13-74.68), respectively. High-risk HPV infection of head and neck mucosa is not uncommon in the Hong Kong population. This study found that 26-30% of oropharyngeal carcinoma was associated with HPV infection, mostly HPV16, and that smoking which predisposes to TP53 mutations was another important risk factor.

Leg muscles of adult rats were stimulated chronically at a low-frequency, and the histochemical reactions of various enzymes (succinic dehydrogenase, mitochondrial alpha-glycerophosphate dehydrogenase, phosphorylase, alkali-ATPase and acid-ATPase), capillary density, resistance to fatigue, and contractile properties were studied. Following stimulation, the histochemical properties of muscle fibres in the fast extensor digitorum longus (EDL) and tibialis anterior (TA) muscles became similar to those of the majority of fibres in the slow soleus muscle. In the soleus muscle, the histochemical properties of the few fast type fibres became similar to the majority of 'slow' fibres so that its fibre composition was homogeneously 'slow'. The stimulated fast muscles also had higher capillary density and were more resistant to fatigue than normal. Despite the prolonged stimulation, the twitch duration of the fast muscles was little changed. This result differs from the findings obtained previously for the rabbit and cat, which show that slowing of contraction can be achieved by low-frequency activity of similar duration. Thus it may be that there is a species difference regarding the readiness with which the transformation of fast to slow muscles can be brought about.

We examined the effects of dorsal root ganglion isografts on the denervation process of skeletal muscle. A segment of sciatic nerve was removed from each of 25 inbred Wistar-Kyoto rats. Fifteen were set aside as controls. In the remaining 10 rats, isogeneic cervical dorsal root ganglia were grafted to the severed distal stump of the common peroneal nerve. Between day 72 and day 286 postoperatively, both controls and recipients were killed after twitch and tetanic tension recording of the extensor digitorum longus was performed. The wet muscle weight and the twitch and tetanic tensions of the denervated extensor digitorum longus in the graft group were significantly greater than those in the control group. The mean area of the denervated tibialis anterior muscle fibers in the graft group also was significantly larger than that in the control group. In electron and light microscopic images, nerve cells along the periphery of each dorsal root ganglion were found surviving with regenerating axons throughout the experimental period. Numerous myelinated axons were observed in the common peroneal nerve of the graft group, and there were significantly more axonal branches in the extensor digitorum longus of the graft group than in the extensor digitorum longus of the control group. Thus sensory nerve fibers from the grafted dorsal root ganglia had certain beneficial effects to slow the denervation process, presumably secreting trophic factors into the denervated muscle. Clinically, we have transferred avulsed dorsal root ganglia in cases of total brachial plexus avulsion directly into denervated skeletal muscle. This procedure, accompanied by nerve crossing procedures, will probably keep denervated skeletal muscle in a better condition until regenerating motor axons from the repair site reach their target muscle.

Fifty normal noninfarct patients and 12 cases with infarcts of the cerebrum were examined with routine magnetic resonance imaging and echo-planar diffusion-weighted imaging. The diffusion-weighted three-dimensional images were reconstructed with volume-rendering processing on workstation. Precentral gyrus, postcentral gyrus, superior parietal lobule, superior frontal gyrus, precentral sulcus, central sulcus, postcentral sulcus, intraparietal sulcus and superior frontal sulcus were best shown of all structures with an arbitrary score of 2.61–2.77. Supramarginal gyrus, middle frontal gyrus, inferior frontal gyrus and lateral sulcus were clearly shown in the majority of the cerebra with average scores of 2.0–2.49; angular gyrus, inferior frontal sulcus and superior temporal gyrus were not demonstrated satisfactorily and their average scores were 1.67–1.89. Middle temporal gyrus, inferior temporal gyrus, superior temporal sulcus and inferior temporal sulcus were difficult to identify, and thus had average scores of 0.87–1.26. Brain surface structures were better displayed in the older group of individuals than in the younger group. The structures in the 12 cases with acute or chronic cerebrum infarcts were also satisfactorily demonstrated with this new technique.