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Biomedical subjects

F Cai

Publications and source records attributed to F Cai.

49 records · Page 3Linked to original sources
PubMed1991

Dominant suppression of adenovirus mediated transformation and insufficiency of p105Rb binding as a condition for oncogenic transformation.

An adenovirus-specific transformation resistant cell line (G2) expressing biologically active E1a proteins and originally isolated as a revertant from Ad2-transformed rat cells (F4), was shown to form stable Rb-E1a and 300K-E1a complexes in immunoprecipitation experiments. Consistent with the transformation resistant phenotype, cell hybrids between G2 and F4 were all nontumorigenic. Retrovirus insertion mutagenesis resulted in tumorigenic cell lines and identified a common locus responsible for the E1a-specific dominant tumor suppressor phenotype of G2 cells.

Adenoviruses, Human↗
PubMed1991

[Determination of the rate of micronucleus formation in lymphocytes in liver diseases and its clinical significance].

The rate of micronucleus formation in lymphocytes was determined in 42 patients (including 10 acute icteric hepatitis B, 15 chronic active hepatitis B (CAH), 8 liver cirrhosis and 9 liver cancer) and 13 normal subjects. The results showed that the rate of micronucleus formation in lymphocytes in the patients with CAH (12.267 +/- 5.298%), liver cirrhosis (12.375 +/- 8.551%) or liver cancer (19.444 +/- 13.324%) was markedly higher than that in those with acute icteric hepatitis B (5.400 +/- 1.430%) or normal subjects (3.308 +/- 1.284%) (P less than 0.01). The rate of micronucleus formation in lymphocytes is higher in the liver cancer group than that in the CAH group or cirrhosis group (P less than 0.05). The rate of presence of two or more micronuclei in the lymphocytes was obviously higher in the liver cancer group (3.667 +/- 4.743%) than that in the liver cirrhosis group (1.500 +/- 1.690%), CAH group (1.467 +/- 1.807%), acute icteric hepatitis B group (0.600 +/- 1.075%) or healthy group (0.462 +/- 0.660%) (P less than 0.01 or less than 0.05). This method is much simpler than the measurement of chromosomal damage, and its reliability is as good as the latter. Measurement of micronuclei in lymphocytes can reflect the degree of liver damage in patients with the infection of hepatitis B virus. It may be used as the subclinical marker of the patients with liver cancer too.

Hepatitis B↗
PubMed1991

Ocular hypersensitivity to thimerosal in rabbits.

Rabbits were immunized to thimerosal conjugates and challenged with specific antigen-sensitized contact lenses. The symptoms of acute ocular hypersensitivity observed included corneal edema, corneal infiltration and erosion, infiltration of the anterior chamber, iritis, conjunctival edema and hyperemia, and a significant increase in mucous production. Occasional evidence of corneal neovascularization and giant conjunctival papillae were seen. All these parameters were assessed on a five-point scale (0 to +4) and tabulated as an ocular index. The index of ocular hypersensitivity correlated with the titers of the serum antibodies to thimerosal. The major class of serum antibodies consisted of immunoglobulin (Ig) G, with IgA compromising approximately 5% of serum antibodies. During the ocular challenge, the total and IgG tear antibody titers increased as a result of increased vascular permeability. The tear IgA titers increased to a lesser extent than IgG. The influx of serum proteins directly into the tear film was confirmed by a protein-dye tracer technique. Histologic analysis showed that the ocular inflammatory response was accompanied by both polymorphonuclear and mononuclear cell infiltrates into the cornea and conjunctiva. In conclusion, thimerosal-immunized rabbits show an exquisite sensitivity to the minute quantities of thimerosal conjugates adsorbed to contact lenses. Both serum and tear antibodies correlate with the severity of the ocular inflammatory response. This model would appear to simulate an antibody-mediated immune complex or Arthus type of ocular hypersensitivity commonly seen to foreign antigens including preservatives.

Animals↗
PubMed1990

Adsorption and removal of protein bound to hydrogel contact lenses.

Tear film proteins are known to adsorb to new hydrogel contact lenses. Using a radioiodine tracing technique, proteins were shown to adsorb to contact lens surfaces. The quantity of protein adsorbed to the contact lenses within 2 to 4 h was 1 to 3 micrograms/lens. The degree of protein adsorption varied from lens-to-lens depending in part on the water content of the lens. High water content ionic lenses bound the most protein, whereas lower water content and nonionic lenses bound less protein. Enzyme cleaning of the protein-coated contact lenses removed about 75% of the adsorbed protein. When the enzyme-cleaned lenses were reincubated with protein, similar quantities were quickly readsorbed within a similar period of time. The rate of readsorption appeared to vary with the type of enzyme used to clean the lenses. Hydrogel lenses adsorb protein from the tear film rapidly and irreversibly. Cleaning the lenses has only a partial and temporary effect on the bound protein. The lens-bound proteins could become partly denatured during their binding to the lenses. These observations suggest a possible role for such proteins in ocular sensitivity to contact lenses.

Adsorption↗
PubMed1990

[Preliminary report of efficacy of diabetic polyneuropathy treated with large dose inositol].

Ten diabetics with polyneuropathy were studied by taking 6g inositol tablets (each tablet contains 0.25g inositol) per day for three months. The results showed that large dose inositol could reduce the severity of clinical symptoms, but there was no improvement of the nerve conduction velocity. The possible mechanism of these changes was discussed. According to the clinical observation of the therapeutic effect in those 10 cases, the authors would deem that large dose inositol is an effective drug for diabetic polyneuropathy, and it is worthy of further clinical trial, but other sensitive indicators should be used to evaluate the efficacy of this drug.

Adult↗
PubMed1989

[Pathogenesis of peripheral neuropathy in streptozotocin-induced diabetes in rats].

Experimental diabetes rats was induced in rats by intraperitoneal streptozotocin. The changes of glucose, sorbitol, fructose and free myoinositol in diabetic sciatic nerve and plasma, the changes of enzyme activity of sciatic nerve in relation to glucose, lipid and protein metabolism were studied during 1, 2, 4, 6, 12 weeks after induction of diabetes. The structural changes of 6 and 12 week diabetic sciatic nerve were observed sequentially by light and electron microscopy during the course of 6 and 12 weeks. The results showed that glucose, sorbitol and fructose in blood and sciatic nerve were increased markedly, but free myo-inositol was normal in blood and decreased in sciatic nerve. The enzyme activity such as ICDH, MDH, LDH, alpha-GPDH all reduced, but the activity of sorbitol dehydrogenase increased. Various ultrastructural changes such as swollen unmyelinated fibers, swollen mitochondria in axon, degenerative changes of myelin sheath and atrophic axon were observed, but no changes was found by light microscopy.

Animals↗
PubMed1989

[Studies of enzyme histochemistry and ultrastructure of the myocardium in rats with streptozotocin-induced diabetes].

Experimental diabetes was induced in wistar rats by intraperitoneal streptozotocin in a single dose of 60-65 mg per kg body weight. The changes of myocardium enzyme histochemistry and ultrastructure were observed during the 2nd, 4th, 6th, 12th week of diabetic state. The glucose metabolism enzyme activities such as ICDH, SDH, MDH, LDH, all decreased. The results indicated that glucose oxidation and glycolysis reduced. In the ventricular myocardium of diabetic rats, varying degrees of ultrastructural change were apparent. Swelling of mitochondria was observed. Focal areas showed myofibrillar degeneration, and cardiac muscle muscle cells showed condensation of nuclear chromatin. Lipid droplets could be seen in the cytoplasm of cardiac myocytes. The ultrastructural changes in the cardiac muscle cells were not accompanied by any changes in the endothelial cells and smooth muscle cells of the small vessels or capillaries. This study provides a strong evidence for the occurrence of a primary myocardial disease in the model of streptozotocin-induced diabetes. The primary cardiomyopathy was not dependent on vascular pathological changes.

Animals↗
PubMed1989

[Clinical observation on hypercortisolism treated with amino-glutethimide].

We reported the clinical results in 13 cases of hypercortisolism treated with amino-glutethimide (AG), which was developed by Tiantsin Research Institute of Medical Industry. Of the thirteen cases nine were confirmed by surgery and histology, and the others were diagnosed clinically. Clinical improvements have been achieved in ten of the thirteen cases over a therapeutic course of 8 to 12 wk with a daily dosage of 1.0 to 2.0 g of AG. Plasma and urinary corticosteroids, as well as plasma testosterone levels were significantly decreased after one-month treatment followed, however, by somewhat return and fluctuation. The high levels of blood glucose and serum insulin were declined after therapy consistent with the decrement of corticoids. Serum potassium levels in hypokalemic patients returned to normal after one month of therapy. Radial bone mineral contents in patients with low bone density returned or closed to normal after three-month treatment. The main side effects of AG are anorexia, nausea, drowsy, tierdness, skin rashes, etc, which are mild and transient. Adrenal hypofunction was seen in one case after treatment.

Adolescent↗
PubMed1988

Thimerosal: an ophthalmic preservative which acts as a hapten to elicit specific antibodies and cell mediated immunity.

A rabbit model for the study of hypersensitivity to thimerosal was established in order to develop better techniques for screening patient sera and tears for specific antibodies to lens care re-agents. Thimerosal (sodium ethylmercury thiosalicylatelate) was successfully coupled to several protein carriers using a water soluble carbodiimide which linked the carboxyl group of thimerosal to free amino groups of the carrier proteins. Thimerosal was also shown to spontaneously react with proteins as detected by the irreversible binding of mercury to the protein carrier. Immunization of rabbits with the chemically coupled thimerosal resulted in the production of antibodies which specifically reacted with thimerosal. The rabbits also manifested delayed and immediate forms of hypersensitivity to the thimerosal conjugates. The ELISA assay for specific serum antibodies was found to be a sensitive, reliable and specific screening tool However, there was no immunological cross reactivity between the chemically coupled thimerosal and the spontaneously coupled thimerosal. Therefore, the epitopes produced by these two reaction mechanisms were probably immunochemically different even though both contained detectable thimerosal derived mercury.

Animals↗
PubMedDate not supplied

Acid resistance of enamel subsurface lesions remineralized by a sugar-free chewing gum containing casein phosphopeptide-amorphous calcium phosphate.

The aim of this clinical study was to investigate the acid resistance of enamel lesions remineralized in situ by a sugar-free chewing gum containing casein phosphopeptide-amorphous calcium phosphate nanocomplexes (CPP-ACP: Recaldent). The study utilized a double-blind, randomized, crossover design with two treatments: (i) sugar-free gum containing 18.8 mg of CPP-ACP, and (ii) sugar-free gum not containing CPP-ACP as control. Subjects wore removable palatal appliances with insets of human enamel containing demineralized subsurface lesions and chewed the gum for 20 min 4 times per day for 14 days. After each treatment the enamel slabs were removed and half of each lesion challenged with acid in vitro for 8 or 16 h. The level of remineralization was determined using microradiography. The gum containing CPP-ACP produced approximately twice the level of remineralization as the control sugar-free gum. The 8- and 16-hour acid challenge of the lesions remineralized with the control gum resulted in 65.4 and 88.0% reductions, respectively, of deposited mineral, while for the CPP-ACP-remineralized lesions the corresponding reductions were 30.5 and 41.8%. The acid challenge after in situ remineralization for both control and CPP-ACP-treated lesions resulted in demineralization underneath the remineralized zone, indicating that the remineralized mineral was more resistant to subsequent acid challenge. The results show that sugar-free gum containing CPP-ACP is superior to an equivalent gum not containing CPP-ACP in remineralization of enamel subsurface lesions in situ with mineral that is more resistant to subsequent acid challenge.

Acetic Acid↗
PubMedDate not supplied

Transformation renders MDR cells more sensitive to polyunsaturated fatty acids.

A series of genetically related cell lines that express mdr genes but differ in their ability to form tumors has been challenged with gamma-linolenate and eicosapentaenoate to verify if the sensitivity of tumorigenic mdr cells to cytotoxic PUFAs differs from the sensitivity of non-tumorigenic mdr cells. The tumorigenic mdr cell lines were derived by transformation of their parental non-tumorigenic mdr cell line with myc and ras oncogenes. Four ras and five myc transformed cell lines were used for the estimation of clonal variability. The data as based on colony forming assays, showed that six out of nine of the tumorigenic mdr cell lines were more sensitive than the non-tumorigenic mdr cells. These results suggest that a tumorigenic phenotype renders mdr cells more sensitive to PUFAs and that PUFA supplementation either alone or in conjunction with existing forms of cancer therapy may have significant clinical implications.

Animals↗