[Differential expression of HSU17714 gene in colorectal cancer and normal colonic mucosa]

HSU17714 is a new gene discovered by subtractive hybridization. Its cDNA is 2,932 bp long and the gene is located at human chromosome 22 as defined by fluorescence in- situ hybridization combined fluorescence R-banding technique. Northern blot and RNA dot blot analyses showed that the expression level of HSU17714 gene was significantly lower in 15 cases of colorectal cancer than that in adjacent normal colonic mucosa. The defective expression of HSU17714 in colorectal cancer suggests that it is a new candidate tumor suppressor gene.

Chalcone Synthase and Flavonol Accumulation in Stigmas and Anthers of Petunia hybrida

Flavonol aglycones are required for pollen germination in petunia (Petunia hybrida L.). Mutant plants lacking chalcone synthase (CHS), which catalyzes the first committed step in flavonoid synthesis, do not accumulate flavonols and are self-sterile. The mutant pollen can be induced to germinate by supplementing it with kaempferol, a flavonol aglycone, either at the time of pollination or by addition to an in vitro germination system. Biochemical complementation occurs naturally when the mutant, flavonol-deficient pollen is crossed to wild-type, flavonoid-producing stigmas. We found that successful pollination depends on stigma maturity, indicating that flavonol aglycone accumulation may be developmentally regulated. Quantitative immunoblotting, in vitro and in vivo pollen germination, and high-performance liquid chromatographic analyses of stigma and anther extracts were used to determine the relationship between CHS levels and flavonol aglycone accumulation in developing petunia flowers. Although substantial levels of CHS were measured, we detected no flavonol aglycones in wild-type stigma or anther extracts. Instead, the occurrence of a conjugated form (flavonol glycoside) suggests that a mechanism may operate to convert glycosides to the active aglycone form.

Biochemical complementation of chalcone synthase mutants defines a role for flavonols in functional pollen

Chalcone synthase catalyzes the initial step of that branch of the phenylpropanoid pathway that leads to flavonoids. A lack of chalcone synthase activity has a pleiotropic effect in maize and petunia mutants: pollen fertility as well as flavonoid synthesis is disrupted. Both maize and petunia mutants are self-sterile due to a failure to produce a functional pollen tube. The finding that the mutant pollen is partially functional on wild-type stigmas led to the isolation and identification of kaempferol as a pollen germination-inducing constituent in wild-type petunia stigma extracts. We show that adding micromolar quantities of kaempferol to the germination medium or to the stigma at pollination is sufficient to restore normal pollen germination and tube growth in vitro and full seed set in vivo. Further we show that the rescue ability resides in particular structural features of a single class of compounds, the flavonol aglycones. This finding identifies another constituent of plant reproduction and suggests that addition or removal of the flavonol signal during pollen germination and tube growth provides a feasible way to control plant fertility.

[Malignant tumors of the lacrimal gland--a report of 27 cases]

We report 27 cases of primary malignant tumors arising from lacrimal gland, including 12 cases with adenoid cystic carcinoma, 9 cases with malignant mixed tumor and 6 cases with other lacrimal gland carcinoma seen in Zhongshan Ophthalmic Center from 1981 to Nov. 1989. These patients with malignant neoplasms accounted for 65.85% of all patients with primary epithelial tumor of lacrimal gland. The clinical presentation, imaging features in X-ray, ultrasonic and CT scan, the diagnosis, differential diagnosis, treatment and prognosis are discussed and analysed.

[Preliminary report of 10 cases of anterior segment eyeball reconstruction]

We performed anterior segment reconstruction by total penetrating Keratoplasty with scleral rim in 10 patients who had infectious ulceration with total corneal necrosis and perforation and prolapse of intraocular contents of the severely damaged 10 eyes, 9 were salvaged and retained a semi-transparent corneal graft with improvement in vision for 6 months or longer. It suggested that, for eyes with severe corneal damage that would otherwise be enucleated, anterior segment reconstruction by corneoscleral transplantation is of value.

Recording pH method of characterizing composition and monitoring dissolution profile of an anhydride-acid copolymer and its salt derivatives

A sensitive potentiometric monitoring method was developed that permits the continuous measurement of the disolution profiles of methyl vinyl ether-maleic anhydride-acid copolymers and salt derivatives. Three distinct rate periods were observed in the dissolution rate of the anhydride copolymer, expressed as percent anhydride dissolved, was independent of sample weight over the weight range studied. The acid form of the copolymer showed only one dissolution rate period, with dissolution being very rapid. The rapid initial pH decrease observed during the first stage of dissolution for a series of anhydride-acid copolymer powder samples correlated closely with the anhydride-acid ratio, permitting chemical characterization of the copolymer functionality simultaneously with the analysis of dissolution profiles. Similarly, the extent of copolymer alkaline salt conversion was inversely proportional to the initial maximum pH increase observed during the first stage of dissolution of these salts. Mechanisms of dissolution of copolymer powder materials are discussed and compared to the dissolution of compressed disks and films reported previously.

Isolation and characterization of tissue-specific isozymes of glucosephosphate isomerase from catfish and conger

In teleosts glucosephosphate isomerase exists as two tissue-specific isozymes. Most tissues contain the more acidic liver-type isozyme, while white muscle contains the more basic isozyme; and a few tissues contain both the liver- and muscle-type isozymes as well as a hybird. The isozymes were isolated from catfish liver and muscle and from conger muscle and shown to be homogeneous by polyacrylamide gel electrophoresis, isoelectric focusing, analytical ultracentrifugation, and rechromatography. Both isozymes are of molecular weight 132,000 (S020,w = 7.0 S) and composed of two subunits of Mr approximately 65,000. The muscle and liver isozymes were shown to have distinct isoelectric points (catfish liver = 6.2; muscle = 7.0) and amino acid compositions. Tryptic peptide maps, after S-carboxymethylation and carbamylation, revealed several distinct differences in the primary structures of the isozymes. Although the isozymes could also be distinguished on the basis of their stabilities, most of their basic catalytic properties were found to be similar. A conger was obtained which was heterozygous for the variant allele at the muscle-glucosephosphate isomerase locus. A comparison of the variant conger muscle isozyme with the wild type revealed a single altered peptide, suggesting a point mutation. The structure-function studies, as well as the genetic studies, clearly establish that the two types of isozymes are of independent genetic origin.