TFP5, a Peptide Derived from Cdk5 Activator p35, Protects Pancreatic β Cells from Glucose Toxicity

We studied the effect of TFP5 on MIN6 cells (cultured mouse islet β cells) treated with different concentrations of glucose (5 or 25 mM). The results were verified in C57BL/6J mice (control; n=12) and db/db mice with type 2 diabetes mellitus (n=12). To synthesize TFP5, peptide p5 (a derivative of p35 protein, activator of cyclin-dependent kinase 5, Cdk5) was conjugated with a FITC tag at the N-terminus and an 11-amino acid TAT protein transduction domain at the C-terminus. TFP5 was employed to inhibit Cdk5 activity and then to evaluate its efficiency in treating experimental type 2 diabetes mellitus. TFP5 effectively inhibited the pathological hyperactivity of Cdk5, enhanced insulin secretion, and protected pancreatic β cells from apoptosis in vitro and in vivo. In addition, TFP5 inhibited inflammation in pancreatic islets by reducing the expression of inflammatory cytokines TGF-β1, TNFα, and IL-1β. These novel data indicates that TFP5 is a promising candidate for treatment of type 2 diabetes mellitus.

[Correlation between urinary sediment spectra and pathological patterns of renal biopsies]

OBJECTIVE

To investigate the clinical value of urinary sediment analysis, a non-invasive diagnostic means, in the evaluation of pathological patterns of renal diseases.

METHODS

A total of 1 140 pairs of matched renal biopsies and fresh fasting morning urine specimens were collected from hospitalized patients in Peking University First Hospital. Their urinary sediments were examined with phase-contrast microscopy; the 24 h urine proteins were measured. Based on urinary sediment features combined with urine protein amount, the spectra of the urine sediments were classified into four types, Type I: hematuria-dominant, with multiple cells and casts; Type II: proteinuria-dominant, with hyaline or fine-granular casts but scanty cells; Type III: renal tubular epithelial cell(RTEC)-dominant, minor proteinuria; Type IV: non-specificurine sediments,minor proteinuria. According to the pathological lesions detected in renal biopsies, the renal diseases were classified into three patterns: proliferative glomerulopathy(P-GP), non-proliferative glomerulopathy (NP-GP) and tubulointerstitial nephropathy(TIN). The urinary sediment spectra of different pathological patterns and the correlation between urinary sediment types and pathological patterns were analyzed. Statistical analyses were performed using kappa test, and χ(2) test, and significance was accepted at P<0.05.

RESULTS

(1) Of the 840 cases of matched urine samples and renal biopsies, 419 cases were diagnosed with P-GP; 375 cases with NP-GP; 46 cases with TIN respectively. (2) The spectra of urine sediments were associated with pathological patterns of the renal biopsies, and 84.0% of the patients with P-GP manifested type I urine sediments; 93.1% of the patients with NP-GP had type II urine sediments; 67.4% of the patients with TIN had type III urine sediments. (3) The correlation between the urinary sediment types and renal pathological patterns was validated in an additional 300 matched samples. The positive predictive values of urinary sediment spectra in predicting renal pathological lesions were 84.8% for typeI to P-GP, 86.0% for type II to NP-GP and 73.7% for type III to TIN, respectively.

CONCLUSION

As a non-invasive diagnostic means, the urinary sediment analysis is valuable in the evaluation of pathological patterns of renal diseases.

The significance of anti-endothelial cell antibodies in patients with lupus nephritis and immunoblotting analysis of the target components

OBJECTIVE

To investigate the prevalence of anti-endothelial cell antibodies and its possible role in the pathogenesis in lupus nephritis.

METHODS

Sera from 58 patients with lupus nephritis were studied. Cellular enzyme linked immunoabsaborbent assay was used to detect anti-endothelial cell antibodies, and immunoblotting technique was performed to determine its specific endothelial target antigens.

RESULTS

36.2% of the patients with lupus nephritis had elevated IgG isotype anti-endothelial cell antibodies. The association was revealed between the presence of anti-endothelial cell antibodies (AECA) and some laboratory and renal biopsy features, such as thrombocytopenia, higher serum IgG level, lower serum C3 level, higher erythrocyte sedimentation rate (ESR), presence of anti-nuclear antibody (ANA), anti-dsDNA antibodies and glomerular thrombosis. Anti-endothelial cell antibodies were consisted of a group of heterogeneous antibodies, and reacted with different endothelial cell antigens which ranged from 12-90 kD in molecular size in immunoblot. A correlation was demonstrated between heavy proteinuria (> 3.5 g/24 hr) and the existence of antibodies against both 27 and 29 kD endothelial cell antigens, an association between the presence of glomerular capillary thrombi and antibody against the 29 kD endothelial cell antigen was also found.

CONCLUSIONS

Lupus nephritis patients with anti-endothelial cell antibodies showed a complex autoimmune disorder and clinical disease activity, and the results also provided an indirect evidence that anti-endothelial cell antibodies might contribute to the pathogenesis of lupus nephritis.

Toxicity screening of materials from buildings with fungal indoor air quality problems (Stachybotrys chartarum)

Samples of building materials visibly contaminated with moisture-related fungi (drywall, fiberglass, wallpaper, wood) were tested with indirect (FFL) and direct (MTT) cytotoxicity screening tests that are particularly sensitive toStachybotrys chartarum toxins. In addition, microscopic, chemical, immunochemical (Roridin A enzyme immunoassay) and mycological culture analyses were performed. In all cases in which building occupants had reported verifiable skin, mucous membrane, respiratory, central nervous system or neuropsychological abnormalities, cytotoxicity was identified. Results of a cytotoxicity screening test of field samples, such as the direct MTT test method, will give investigators of health problems related to indoor air quality problems important toxicity information.