Activation of HIF-1α (hypoxia inducible factor-1α) prevents dry eye-induced acinar cell death in the lacrimal gland

The pathogenesis of immune-mediated lacrimal gland (LG) dysfunction in Sjögren's syndrome has been thoroughly studied. However, the majority of dry eye (DE) is not related to Sjögren type, and its pathophysiology remains unclear. The purpose of this study was to determine and investigate the protective mechanisms against DE stress in mice. DE induced prominent blood vessel loss without apoptosis or necrosis in the LG. Autophagic vacuoles, distressed mitochondria, and stressed endoplasmic reticulum were observed via electron microscopy. Immunoblotting confirmed the increase in autophagic markers. Glycolytic activities were enhanced with increasing levels of succinate and malate that, in turn, activated hypoxia-inducible factor (HIF)-1α. Interestingly, the areas of stable HIF-1α expression overlapped with COX-2 and MMP-9 upregulation in LGs of DE-induced mice. We generated HIF-1α conditional knockout (CKO) mice in which HIF-1α expression was lost in the LG. Surprisingly, normal LG polarities and morphologies were completely lost with DE induction, and tremendous acinar cell apoptosis was observed. Similar to Sjögren's syndrome, CD3⁺ and CD11b⁺ cells infiltrated HIF-1α CKO LGs. Our results show that DE induced the expression of HIF-1α that activated autophagy signals to prevent further acinar cell damage and to maintain normal LG function.

A Study on the Reactive Compatibilization of a PBT/LCP Blend: Catalyst Effect

The in situ compatibilization of poly(butylene terephthalate) (PBT) with liquid crystalline polymer (LCP) via catalyzed transesterification reaction was examined through thermal, rheological, morphological and mechanical studies. The addition of catalyst, dibutyltindilaurate, was found to promote the transesterification between PBT and LCP. Maintenance of high vacuum environment was required to produce the high molecular weight copolymers in the reactor, which, acting at the interface, diminished the size of the dispersed phase (LCP) and enhanced interfacial adhesion that led to an early increase of the flexural strength. Flexural strength was reduced after long time reaction due to the chain scission. Transesterification confirmed by NMR spectroscopic analysis played a major role in the interchange process.

Nm23 expression in human gastric cancers - possible correlation of nm23 with lymph-node metastasis

In order to elucidate the relationship between nm23 and metastasis in human gastric cancers, we analyzed gene and protein expression of nm23-H1 using Northern blot and immunohistochemical techniques. nm23-H1 gene expression was identified in 17 out of 19 gastric cancer tissues. The signals in the tumor tissues presenting regional lymph node metastasis seem to be lower than those in the tumor tissues without regional lymph node metastasis, suggesting a role of nm23-H1 in the regional lymph node metastasis in the gastric cancers. However, the protein expression detected immunohistochemically was not correlated to the gene expression, partly because of difficulty in quantifying the amount of protein. Expression of the nm23-H1 gene as well as the nm23-H1 protein in the tumor tissues was higher than those in the corresponding normal mucosae. This suggests a linkage of nm23-H1 in the process of the gastric cancer progression. We also analyzed the sequence abnormalities of the nm23-H1 gene in the gastric cancer tissues using a direct sequencing technique, no mutations were observed.