Activation of the hexosamine pathway leads to deterioration of pancreatic beta-cell function through the induction of oxidative stress

It is known well that activation of the hexosamine pathway causes insulin resistance, but how this activation influences pancreatic beta-cell function remains unclear. In this study, we found that in isolated rat islets adenovirus-mediated overexpression of glutamine:fructose-6-phosphate amidotransferase (GFAT), the first and rate-limiting enzyme of the hexosamine pathway, leads to deterioration of beta-cell function, which is similar to that found in diabetes. Overexpression of GFAT or treatment with glucosamine results in impaired glucose-stimulated insulin secretion and reduction in the expression levels of several beta-cell specific genes (insulin, GLUT2, and glucokinase). Additionally, the DNA binding activity of PDX-1, an important transcription factor for these three genes, was markedly reduced. These phenomena were not mimicked by the induction of O-linked glycosylation with an inhibitor of O-GlcNAcase, PUGNAc. It was also found that glucosamine increases hydrogen peroxide levels and that several hexosamine pathway-mediated changes were suppressed by treatment with the antioxidant N-acetyl-l-cysteine. In conclusion, activation of the hexosamine pathway leads to deterioration of beta-cell function through the induction of oxidative stress rather than O-linked glycosylation. Thus, the hexosamine pathway may contribute to the deterioration of beta-cell function found in diabetes.

[Value of surgical margin in directing the treatment of early laryngeal carcinoma after partial laryngectomy]

OBJECTIVE

To investigate the value of surgical margin in directing the treatment of early laryngeal carcinoma after partial laryngectomy.

METHODS

We studied 87 cases of T1N0M0 and T2N0M0 laryngeal carcinoma in which the surgical margins were reserved during partial laryngectomy. The recurrence and survival rates between the positive and negative margin groups were compared; the survival between the positive margin groups with postoperative radiotherapy and negative groups; the survival between groups with and without postoperative radiotherapy in negative margins.

RESULTS

Recurrent rate of the negative group was lower than that of the positive group (5.8% vs 33.3%, chi 2 = 10.64 P = 0.001). The estimated survival was higher in the negative group than in the positive group(P = 0.011), and also in tumor-free time(P = 0.007). The survival of those with positive surgical margin and received postoperative RT was lower than that with negative margins(P = 0.01). In the negative group, the difference in the survival between those with or without postoperative RT was not significant (P = 0.405).

CONCLUSION

The prognosis of the positive margin group of the early laryngeal carcinoma was worse than that of the negative group, but postoperative RT can improve it; it is not necessary for the negative group to be treated by postoperative RT.

[Relationship between operative time and therapeutic effectiveness after the optic nerve injuries]

OBJECTIVE

To understand the relationship between the operative opportunity and effectiveness in the optic nerve injuries.

METHOD

Twenty-three cases with optic nerve injuries were undertaken optic canal decompression.

RESULT

The visual acuity in 13 cases were improved after the operation, and progressed about 0.233 averagely. The average time from injuries to operations was (12.90 +/- 16.77) d (3-22 d) in ineffective group. 7 cases of hypoactivity of eyeball recovered in 8 cases.

CONCLUSION

The optic nerve decompression should be done after the patients were treated with megadose of steroid for 48 hours and did not recover. The time had better be no more than 7 days.

[Determination of sarsasapogenin in "tian dong" by TLCS]

This paper reported the determination of sarsasapogenin in 12 samples from 7 species and varieties of Asparagus genus whose commercial name is "Tian-Dong"(Radix Asparagi), Asparagus cochichinensis(Lour.) Merr, A. cochichinensis (lour.) Merr. var. gaudichaudianus (Kunth) X. D. Luo and G. J. Xu, A. taliensis Wang et Tang, A. munitus Wang et Tang, A. myriacanthus Wang et S. C. Chen, A. meioclados Levl and A. trichoclados (Wang et Tang) Wang et S. C. Chen by TLCS. The results showed that it was no pertinence between content of sarsaspogenin with the species, and the content of sarsasapogenin in the tuberous roots was inverse ratio with the commercial grande in same species.

[Study of quantitative calibration model suitability in near-infrared spectroscopy analysis]

Near-infrared spectroscopy is a fast, high efficiency and low cost analytical technique, that depended on analytical models which are built through near-infrared spectra, the primary method results of calibration set and chemometrics methods. The reliability of analytical results mostly depends on the suitability of analytical model to unknown samples. To judge the suitability of analytical model, a new method is presented that combine principle factor analysis (PCA) and Mahalanobis distance. It is different with traditional method, that the Mahalanobis distance is calculated through PCA factor scores. It can avoid the wavelengths selection problem in traditional method of spectral Mahalanobis distance. Through the determination of cetane number of diesel fuel, some factors that affect model suitability judgement are discussed.

[Study on the photoluminescence spectrum of nickel passivation treatment of porous silicon]

A new method for electrolysis passivation treatment of porous silicom (PS) in NiCl2 is reported in this paper. The photoluminescence (PL) spectra of PS treated in different time is observed, the spectra show that peak intensity is 2.5 times stronger than that without treatment, peak wavelength is 33 nm blue shift when PS is treated properly. The phenomenon caused is that the results of the SiHx change into SiNix when replaced H by Ni on surface of PS.

[The transcription of interleukin-8 in gastric epithelial cells by Helicobacter pylori strains in Chinese]

OBJECTIVE

To observe the effect of the vac A genotype and the existence of cag pathogenicity island (cag PAI) of Helicobacter pylori (Hp) isolated from Chinese patients on the transcription of IL-8 in gastric epithelial cells.

METHODS

The genotype of vac A and the existence of cag PAI of Hp were determined by gene sequencing and Southern blot, respectively; the constructed L5F11 cells were cocultured with the bacteria and the transcription of interleukin-8(IL-8) was indicated by luciferase activity and the cytotoxin activity showed by using HeLa cell vacuolating assay.

RESULTS

The ability to induce luciferase by the strains with complete cag PAI (n = 15) was much higher than that by the wild cag negative strain G50[(0.47 +/- 0.09) x 10(6) cpm vs (0.13 +/- 0.02) x 10(6) cpm, P < 0.01] and there was no difference in the luciferase activity induced by the strains with partial cag (n = 4) and by G50[(0.23 +/- 0.08) x 10(6) cpm vs (0.13 +/- 0.02) x 10(6) cpm, P > 0.05]; Also no difference was found in the luciferase activity induced by the strains with vac A s1/m1 (n = 5) and the strains with s1/m2 (n = 14) [(0.29 +/- 0.12) x 10(6) cpm vs (0.53 +/- 0.41) x 10(6) cpm, P > 0.05] although the formers had much higher vacuolating cytotoxin activity than the latters (P < 0.001).

CONCLUSION

The transcription of IL-8 in gastric epithelial cells induced by Hp isolated from Chinese patients was associated with the existence of cag PAI and not with the genotype of vac A.

[Morphology of abdominal aortic aneurysm and its clinical importance]

OBJECTIVE

To investigate the morphology of abdominal aortic aneurysms(AAA) and anatomical importance in endovascular surgery.

METHODS

The images of AAA were measured by spiral CT angiography in 30 patients from January 1998 to December 2000.

RESULTS

The mean diameter of AAA was 5.9 cm (range: 4.0-12.2). The diameter of AAA was positively correlated with neck angle (r = 0.47, P < 0.05) and negatively correlated with neck length(r = -0.41, P < 0.05). Twelve patients(40%) were anatomically feasible for endovascular repair (EVR); 18 patients were excluded for EVR due to angulated proximal necks (mean 88.8 degrees, range 70 degrees-110 degrees) (16 patients; 53.3%), short neck (1; 3.3%), and unilateral common iliac artery occlusion with thrombosis in neck (1; 3.3%).

CONCLUSION

The angulated neck was a major single factor for excluding Chinese patients from EVR.

XPD exon 10 and 23 polymorphisms and DNA repair in human skin in situ

Forty-four Finnish volunteers who were previously studied with regard to the repair rate of UV-specific cyclobutane pyrimidine dimers in the skin were genotyped for XPD polymorphisms at codons 312 (exon 10 G-->A, Asp-->Asn) and 751 (exon 23 A-->C, Lys-->Gln). The repair rate was measured at 24 h for two different cyclobutane dimers. The data did not show consistent XPD genotype-specific differences in DNA repair rates among all subjects. The combined exon 10 AA and exon 23 CC genotype was associated with an approximately 50% depression of repair rate but this was of borderline statistical significance. However, the exon 23 C allele was associated with depressed repair among subjects aged 50 years or older and the result was consistent with both dimers.

[Revision endoscopic sinus surgery on chronic sinusitis and polyps]

OBJECTIVE

To study the indications, surgical landmarks, surgical significance, complications and operative avoidance of revision endoscopic sinus surgery on chronic sinusitis and polyps.

METHOD

We performed revision endoscopic sinus surgery on 112 cases of chronic sinusitis and polyps under controlled hypotension anaesthesia by using the Messerklinger technique and Stryker debrider.

RESULT

89 cases were successful and 17 unresolved, 6 failed, all the complications consist of cerebrospinal fistula in one, orbital hematoma in four, increased tearing in three and profuse bleeding in 6 patients.

CONCLUSION

Revision endoscopic sinus surgery was advised in case of sinuous obstruction caused by uncontrolled lesions under postoperative care, which can do good for adhesion and obstruction except nasal polyposis. The remanet of the middle turbinate and the upper arch of choana were helpful operative landmarks. Preoperative CT scan decrease the complications.

Physician executives report high job satisfaction. Summary of findings from a survey of senior physician executives

The role of the senior physician executive is well established in American hospitals and health systems. There is little research, however, on overall physician executive job satisfaction, their perceptions of their organizational role and job performance, or their views of the medical staffs with which they work. A recent survey of physician executives examined these and other areas. It found physician executives to be quite satisfied with their jobs. What follows is a summary of the findings. An article based on the survey will be featured in a future issue of The Physician Executive.

[Improvement of proliferation of intrasplenically transplanted fetal hepatocytes after immunoadsorption]

OBJECTIVE

To investigate whether removing the compartments of hemopoietic stem cells by immunoadsorption would improve the proliferation of fetal hepatocytes after transplantation.

METHODS

The purification of fetal hepatocytes was performed by immunoadsorption, and the proliferative capability of fetal hepatocytes after intrasplenic transplantation was evaluated by image analysis and flowcytometry analysis.

RESULTS

The yield of fetal hepatocytes after immnoadsorption was (2~3)+/-10(7) in total per fetal liver and the viability is over 85%. The square densities of fetal hepatocytes with image analysis at 3, 7, and 14 days after transplantation were (1603+/-337), (3788+/-605), (8129+/-1025) micrometer(2)/mm(2), and the adult hepatocytes were (1007+/-128), (2013+/-242), (3780+/- 772) mum(2)/mm(2) accordingly. The S phase rates of fetal hepatocytes by flowcytometry analysis were (14.25+/-4.11)%, (16.07+/-5.35)%, and (17.32+/-5.17)%, and the rates of adult hepatocytes were (5.66+/-1.02)%, (4.98+/- 0.74)%, and (6.83+/-1.37)% correspondingly. The S phase rates and the square densities of fetal hepatocytes were significantly higher than those of adult hepatocytes.

CONCLUSIONS

Fetal hepatocytes are highly proliferative and potentially suitable as donor cells in hepatocytes transplantation after immunoadsorption.

Electrochemiluminescence of tris(2,2'-bipyridine)ruthenium(II) immobilized in poly(p-styrenesulfonate)-silica-Triton X-100 composite thin-films

The electrochemiluminescence (ECL) of tris(2,2'-bipyridine)ruthenium(II) [Ru(bpy)3(2+)] immobilized in poly(p-styrenesulfonate) (PSS)-silica-Triton X-100 composite films was investigated. The cooperative action of PSS, sol-gel and Triton X-100 attached Ru(bpy)3(2+) to the electrode strongly, and the presence of Triton X-100 prevented drying fractures of the sol-gel films during gelation and even on repeated wet-dry cycles. The modified electrode was used for the ECL detection of oxalate, tripropylamine (TPA) and NADH in a flow injection analysis (FIA) system with a newly designed flow cell. The detection scheme exhibited good stability, short response time and high sensitivity. Detection limits were 0.1, 0.1 and 0.5 micromol L(-1) for oxalate. TPA and NADH, respectively, and the linear concentration range extended from 0.001 to 1 mmol L(-1) for the three analytes. Applications of the flow cell in ECL and electrochemical detection, as well as the immobilization of reagents based on the cooperative action, are suggested.

Role of the cystine-knot motif at the C-terminus of rat mucin protein Muc2 in dimer formation and secretion

DNA constructs based on the 534-amino-acid C-terminus of rat mucin protein Muc2 (RMC), were transfected into COS cells and the resultant (35)S-labelled dimers and monomers were detected by SDS/PAGE of immunoprecipitates. The cystine-knot construct, encoding the C-terminal 115 amino acids, appeared in cell lysates as a 45 kDa dimer, but was not secreted. A construct, devoid of the cystine knot, failed to form dimers. Site-specific mutagenesis within the cystine knot was performed on a conserved unpaired cysteine (designated Cys-X), which has been implicated in some cystine-knot-containing growth factors as being important for intermolecular disulphide-bond formation. Dimerization of RMC was effectively abolished. Each cysteine (Cys-1-Cys-6) comprising the three intramolecular disulphide bonds of the cystine knot was then mutated. Dimer formation was impaired in each case, although much less so for the Cys-3 mutant than the others. Abnormal high-molecular-mass, disulphide-dependent aggregates formed with mutations Cys-1, Cys-2, Cys-4 and Cys-5(,) and were poorly secreted. It is concluded that the intact cystine-knot domain is essential for dimerization of the C-terminal domain of rat Muc2, and that residue Cys-X in the knot plays a key role. The structural integrity of the cystine knot, maintained by intramolecular bonds Cys-1-Cys-4, Cys-2-Cys-5 and Cys-3-Cys-6, also appears to be important for dimerization, probably by allowing correct positioning of the unpaired Cys-X residue for stable intermolecular cystine-bond formation.

[Antioxidation of flavones of wheat germ on mammary tumor of rats]

The effect of flavonoids of wheat germ on mammary tumor of rats induced by 7,12-dimethylben(a) anthracene (DMBA) was investigated. Sprague-Dawley female rats (50 day-old, weighted around 176 g) were randomly divided into 4 groups. The negative and positive control group were fed on stoke diet. The high and low dose test groups were fed on diets with wheat germ flavonoids 10 and 2 g/kg respectively. Except rats in the negative control group, each rat was given DMBA 15 mg dissolved in 1.5 ml vegetable oil by tube feeding. After the administration of DMBA for 24 weeks, the incidence of tumor in the high dose test group was lower than that in the positive control group. The activity of blood and liver glutathione peroxidase (GSH-Px) and peroxidase dismutase(SOD) in the test groups was significantly higher than those in the positive control group, while the MDA level was significantly lower. The results suggested that the effect of flavonoids on inducing peroxidase might be one of the chemical prevention mechanisms on mammary tumors.

Regulation of alpha-smooth muscle actin and CRBP-1 expression by retinoic acid and TGF-beta in cultured fibroblasts

We have reported that Cellular Retinol Binding Protein-1 (CRBP-1) is expressed de novo during skin wound healing by a proportion of fibroblastic cells which then differentiate into myofibroblasts and express alpha-smooth muscle actin. In fibroblasts cultured from different tissues we have shown that alpha-smooth muscle actin expression, mainly controlled by Transforming Growth Factor-beta (TGF-beta), is also regulated by retinoic acid and that CRBP-1, known to be a retinoic acid-responsive gene, is modulated by TGF-beta. The aim of the present study has been to investigate the relationships between retinoic acid and TGF-beta in regulating the expression of CRBP-1 and alpha-smooth muscle actin in cultured rat subcutaneous tissue fibroblasts. We have observed that the TGF-beta-induced, but not the retinoic acid-induced, alpha-smooth muscle actin expression is associated with a modulation of endogenous TGF-beta and TGF-beta receptors, suggesting that the action of retinoic acid on alpha-smooth muscle actin expression is not mediated by TGF-beta. The expression of CRBP-1 is regulated at the transcriptional level by TGF-beta and retinoic acid but not synergistically, suggesting a possible common pathway. However, retinoic acid, but not TGF-beta, increases the transcription of a transiently transfected chimeric construct containing the retinoic acid response element of the CRBP-1 promoter, indicating that TGF-beta does not influence CRBP-1 through the retinoic acid pathway. Our results indicate that distinct pathways regulate the genes involved in the appearance and evolution of the myofibroblastic cells. The characterization of these pathways will be helpful for the design of drugs influencing wound healing.

[Subtotal laryngectomy reconstructed by platysma myocutaneous flaps]

OBJECTIVE

To study the feasibility, surgical techniques and the results of laryngeal function preservation during subtotal laryngectomy in laryngeal carcinoma.

METHODS

A retrospective review was made of 13 patients treated by subtotal laryngectomy and laryngeal reconstruction from 1991 to 1996. Eleven patients were male and 2 were female. The age ranged from 46 to 72 years, with a mean of 53.25. All cases were of stage IV. The essence of this operation is to reconstruct the new larynx with two platysma myocutaneous flaps following subtotal laryngectomy.

RESULTS

The success rate of voice rehabilitation was 100%. Among them, the acceptability rating scores in 11 cases were 7 and the intelligibility scores ranged from 95% to 98%. The other two cases had acceptability 5 and intelligibility form 90% to 94%. The three-year survival rate was 84.6% (11/13), 5-year survival rate was 76.9% (10/13).

CONCLUSION

This form of laryngeal reconstruction in subtotal laryngectomy is helpful to restore laryngeal function and decrease the rate of total laryngectomy. The procedure is easy, safe and applicable to patients treated by subtotal laryngectomy.

[Observation on the kinetic process in replantation of the recurrent laryngeal nerve of the dog]

OBJECTIVE

In order to provide experimental foundation for replantation in the recurrent laryngeal nerve(RLM) of the laryngeal reconstruction and laryngeal transplantation.

METHOD

The left RLN of ten caine dogs were cut. The histopathology of the cut RLN were observed under the microscope after operation (two dogs) and 3.5 hours later (two dogs). Meanwhile the RLN were sewed up under the microscope at once. The kinetic process in regeneration of the RLN were observeded 1 week (two dogs), 2 week (two dogs) and 4 week (two dogs) after the replantation.

RESULT

The replantation of RLN of six dogs succeeded.

CONCLUSION

The results confirmed that sewing up the cut RLN at once is helpful to get normal regeneration in the replantation.

[Composition and structure of bioflocculant BP25]

A strain of Bacillus megaterium screened from activated sludge could produce exocellular flocculant. The flocculant was purified through ethanol precipitation and Sephadex S-500 column chromatography. The purified flocculant BP25 was assayed by Bradford reaction, agarose gel electrophoresis and Sulfate-phenol method. The results showed that BP25 was a kind of polysaccharide which contains 36.97% O, 6.28% H, 47.00% C, 0% No NMR assay showed BP-25 contains no uronic acid. Gas-chromatography assay combined with thin-layer chromatography of acid hydralate revealed that BP25 contains Glucose and Mannose with the mole ratio of 4:1. Methylation analysis revealed the polysaccharide contains alpha-1, 6 glycosidicbond and alpha-1, 3 glycosidicbond. The main chains are comprised of Glucose and all the Mannose are in the side chains. Possible repeating unit structure was deduced.

[Prognostic influence of parapharyngeal space involvement in nasopharyngeal carcinoma]

OBJECTIVE

To explore the prognostic influence of parapharyngeal space involvement in nasopharyngeal carcinoma (NPC).

METHODS

From Jan. 1987 to Dec. 1994, 197 previously untreated NPC patients were examined by CT scan. The prognostic factors ware evaluated by univariate and multivariate analyses on SPSS 8.0 software.

RESULTS

The actual survival rate, disease-free survival rate and local failure-free rate were negatively affected by the presence of parapharyngeal space involvement (P = 0.0115, P = 0.0035, P = 0.0367). The 5-year actual survival rate, disease-free survival rate and local failure-free rate in patients without tumor invasion to parapharyngeal space was 87.9%, 88.0% and 96.9%, respectively. The survival rate in patients with tumor invasion to prestyloid space was 75.0%, 71.2% and 93.7%, respectively. That in patients with tumor invasion to poststyloid space was 60.5%, 57.7% and 86.8%, respectively. The 5-year distant metastasis-free survival rate was 88.1% in patients without poststyloid involvement as compared to 73.8% in those with poststyloid involvement.

CONCLUSION

The survival and local tumor control are affected by parapharyngeal space involvement. Distant metastasis is more likely to occur when the tumor growth involves poststyloid space.

[Evaluation on the cytotoxicity of Gallium alloy by MTT-assay]

OBJECTIVE

To test the cytotoxicity of Gallium alloy, a new mercury-free dental restorative material.

METHODS

L-929 mouse fibroblasts were used to detect the cell relative proliferation rate of Gallium alloy and high-copper amalgam by MTT-assay.

RESULTS

The results indecated that the relative growth rate induced by Gallium alloy was high (93.0% +/- 4.9% 2ds, 102.0% +/- 3.5% 4ds, 107.2% +/- 4.2% 7ds), and the cytotoxicity of Gallium alloy was 0 grade according to the Test Standard of Shanghai Medical Biomaterial, meaning Gallium alloy had no significant cytotoxicity and the relative growth rate of Gallium alloy was higher than that of high-copper amalgam. The high-copper amalgam showed medium cytotoxicity.

CONCLUSION

Gallium alloy has no significant cytotoxicity.