Non-specific tolerance induced by staphylococcal enterotoxin B in treating high risk corneal transplantation in rats

AIMS

To explore the role of staphylococcal enterotoxin B (SEB) in treating high risk corneal keratoplasty in rats.

METHODS

Rat corneal high risk transplantation rejection models were set up using Fisher 344 and Lewis rats. The experimental rats were injected intraperitoneally with 0.2 ml SEB at different concentrations before keratoplasty. The rejection indexes of the allograft were recorded and the lymphocyte infiltration in the allograft and the percentage of the lymphocyte subpopulation in the lymphatic organs were also examined. Lymphocyte proliferation ability and the concentration of IL-2 and IL-10 in the serum were also evaluated.

RESULTS

Compared with the control group, SEB prolonged the survival time of the allograft significantly from 7 to 12 days. It could also reduce CD4(+) and CD8(+) lymphocyte infiltration in the allograft and minimise the percentage of CD4(+) and CD8(+) lymphocytes in the lymphatic organs. The lymphocyte proliferation ability was also weakened. However, the percentage of CD4(+) NK T lymphocytes in the lymphatic organs was raised. The serum concentration of IL-10 was higher but IL-2 was lower in the SEB treated groups.

CONCLUSIONS

SEB prolonged the survival time of the allograft in high risk rat corneal allo-transplantation, which may be caused by T cell deletion and acquisition of non-specific tolerance.

A convenient and rapid sample repositioning approach for atomic force microscopy

A novel repositioning approach is described for repeated observations of a specimen at a close proximal location in the atomic force microscope. The approach is similar to keystone architecture, whereby the repositioning is achieved by forming a male structured base for the specimen, and a corresponding female counterpart as the frame. For the combination of an acrylic acid frame and a metal base, 90% translation shifts are less than 10 microm, and almost all angular disorientations are within +3 degrees to -3 degrees . Nanometre-scale surface features can be relocated easily and reliably even after 40 imaging-removal-imaging cycles, dipping the specimen in solutions or heating up to 500 degrees C.

Enterovirus replication in valvular tissue from patients with chronic rheumatic heart disease

AIMS

To investigate the involvement of enterovirus infection in chronic, rheumatic heart disease.

METHODS AND RESULTS

Formalin-fixed, paraffin-embedded, surgical samples of valve tissue were examined for the presence of enteroviral RNA and virus capsid protein VP1 by in situ hybridization and immunostaining. Of 53 cases, 33 were patients with chronic rheumatic heart disease and 20 had Marfan's syndrome or degenerative valve disease. Enterovirus RNA was detected in 8 (24.2%) of 33 patients with chronic rheumatic heart disease by in situ hybridization using strand-specific oligonucleotide probes, complementary to conserved sequences in enterovirus genomic (positive strand) RNA. The replication template (negative strand) RNA also was found in seven of these eight cases. The viral capsid protein VP1 was detected in 16 (48.5%) of 33 patients with chronic rheumatic heart disease by immunohistochemistry and correlated with viral RNA detection. Virus was localized generally to valvular tissue. Neither viral RNA nor capsid protein VP1 were found in valvular tissue from any of the 20 comparison cases.

CONCLUSIONS

This is the first demonstration of detection and localization of both enterovirus RNA and capsid protein in chronic rheumatic heart disease. The presence of negative strand RNA and VP1 indicates enteroviral RNA replication and protein synthesis and suggests an aetiological role of enterovirus in the pathogenesis of chronic rheumatic heart disease.

RyR3 amplifies RyR1-mediated Ca(2+)-induced Ca(2+) release in neonatal mammalian skeletal muscle

The neonatal mammalian skeletal muscle contains both type 1 and type 3 ryanodine receptors (RyR1 and RyR3) located in the sarcoplasmic reticulum membrane. An allosteric interaction between RyR1 and dihydropyridine receptors located in the plasma membrane mediates voltage-induced Ca(2+) release (VICR) from the sarcoplasmic reticulum. RyR3, which disappears in adult muscle, is not involved in VICR, and the role of the transiently expressed RyR3 remains elusive. Here we demonstrate that RyR1 participates in both VICR and Ca(2+)-induced Ca(2+) release (CICR) and that RyR3 amplifies RyR1-mediated CICR in neonatal skeletal muscle. Confocal measurements of intracellular Ca(2+) in primary cultured mouse skeletal myotubes reveal active sites of Ca(2+) release caused by peripheral coupling between dihydropyridine receptors and RyR1. In myotubes lacking RyR3, the peripheral VICR component is unaffected, and RyR1s alone are able to support inward CICR propagation in most cells at an average speed of approximately 190 microm/s. With the co-presence of RyR1 and RyR3 in wild-type cells, unmitigated radial CICR propagates at 2,440 microm/s. Because neonatal skeletal muscle lacks a well developed transverse tubule system, the RyR3 reinforcement of CICR seems to ensure a robust, uniform, and synchronous activation of Ca(2+) release throughout the cell body. Such functional interplay between RyR1 and RyR3 can serve important roles in Ca(2+) signaling of cell differentiation and muscle contraction.

[Biological stabilities and identification of a highly metastatic subpopulation from a human osteosarcoma cell line]

OBJECTIVE

To investigate the biological stabilities and the identification of a human highly metastatic osteosarcoma subpopulation.

METHODS

Tumor pieces of the cell were inoculated into nude mice orthotopically. Lung node metastatic foci were obtained by culturing, the procedure was repeated for 3 cycles. Changes were observed in intra-tibial tumor growth, pulmonary metastatic rate in vivo, morphological characteristics, expressions of BMP, vimentin, actin, NEC and karyotype analyses of every passage in vitro.

RESULTS

The intra-tibial tumor growth rates were 100%, the proliferation abilities were stable, and the pulmonary metastatic rates were higher than 80%. The expressions of BMP, vimentin, actin were positive, but the expression of NSE was negative. Its morphological characteristics the antigen-positive substances and karyotype were similar to those observed in human osteosarcoma.

CONCLUSION

SOSP-M1 with very stable biological characteristics is a good model for the study of human osteosarcoma.

[The 5-year death analysis in patients with nasopharyngeal carcinoma treated with radiotherapy]

OBJECTIVE

To study the main death cause of nasopharyngeal carcinoma (NPC) treated with radiotherapy for 5 years.

METHOD

An analysis had been made to evaluated the 5-year death in 165 patients with NPC treated with radiotherapy.

RESULT

The death correlates strongly with the clinical stage, type and radiation dose (P < 0.05).

CONCLUSION

The distant metastasis and local recurrence are the main death cause of NPC.

[Acidity and acid buffering capacity of aerosols during sand-dust storm weather in Beijing]

In the spring of 2000, there were 12 sand-dust storms in Beijing. 2 sand-dust storms were experienced in time and mass concentrations, elementary concentrations acidity and acidic buffering capacity of TSP(Total Suspended Particulate, < 100 microns) and PM10(Inhalable particulate, < 10 microns) were sampled and analyzed. Results showed that pollution level of aerosols was extremely high. However, the acidity of aerosols was relatively low and the aerosols had very strong acid buffering capacity for acidification. Therefore, the aerosols brought about by the sand-dust storms could avoid the occurrence of acidic precipitation to some extent.

Synergistic movements of Ca(2+) and Bax in cells undergoing apoptosis

Apoptosis is a physiological counterbalance to mitosis and plays important roles in tissue development and homeostasis. Cytosolic Ca(2+) has been implicated as a proapoptotic second messenger involved in both triggering apoptosis and regulating cell death-specific enzymes. A critical early event in apoptosis is associated with the redistribution of Bax from cytosol to mitochondria and endoplasmic reticulum (ER) membranes; however, the molecular mechanism of Bax translocation and its relationship to Ca(2+) is largely unknown. Here we provide functional evidence for a synergistic interaction between the movements of intracellular Ca(2+) and cytosolic Bax in the induction of apoptosis. Overexpression of Bax in cultured cells causes a loss of ER Ca(2+) content. Depletion of ER Ca(2+) through activation of the ryanodine receptor enhances the participation of Bax into the mitochondrial membrane. Neither Bax translocation nor Bax-induced apoptosis is affected by buffering of cytosolic Ca(2+) with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, suggesting that depletion of ER Ca(2+) rather than elevation of cytosolic Ca(2+) is the signal for cell apoptosis. This dynamic interplay of Ca(2+) and Bax movements may serve as an amplifying factor in the initial signaling steps of apoptosis.

Regulation of KChIP2 potassium channel beta subunit gene expression underlies the gradient of transient outward current in canine and human ventricle

Expression of four members of the KChIP family of potassium channel beta subunits was examined in canine heart. Only one member of the gene family, KChIP2, was expressed in heart. There was a steep gradient of KChIP2 mRNA expression across the canine ventricular free wall. KChIP2 mRNA was 25-fold more abundant in the epicardium than in the endocardium, and this gradient paralleled the gradient in transient outward current (Ito) expression. In contrast, Kv4.3 potassium channel alpha subunit mRNA was expressed at equal levels across the ventricular wall. There was no difference in the pharmacological sensitivity of epicardial and endocardial Ito channels to flecainide, suggesting that the current is produced by the same channel in the two tissues. A similar gradient of KChIP2 expression was found across the ventricular wall of human heart, but not rat heart. It is concluded that transcriptional regulation of the KChIP2 beta subunit gene, rather than the Kv4.3 [alpha] subunit gene, is the primary determinant regulating the transmural gradient of Ito expression in the ventricular free wall of canine and human heart.

[An experimental study on subconjunctival interleukin-1 receptor antagonist for promotion of corneal transplant survival]

OBJECTIVE

To determine whether the subconjunctival application of interleukin-1 receptor antagonist (IL-1ra) can prolong the corneal graft survival in the rat model of orthotopic penetrating keratoplasty.

METHODS

For all experiments, F344 corneas were transplanted into LOU (major histocompatibility-disparate) eyes. Experimental groups received subconjunctival injection of 50, 100 and 200 microg IL-1ra respectively, and the control group received the same volume of 0.9% normal saline instead for consecutive 2 weeks. All transplants were evaluated for 4 weeks after surgery for signs of rejection.

RESULTS

The mean survival time (MST) of the grafts of the experimental groups was increased significantly (t = 0.00, P < 0.01) in comparison with the control group. The MST of the IL-1ra 200 microg group was increased significantly than that of the IL-1ra 50 microg group (t = 0.00, P < 0.01). Furthermore, the IL-1ra-treated grafts had significantly less corneal inflammation, infiltration, lower levels of opacity, edema, neovascularization and rejection index compared with the control group.

CONCLUSIONS

Subconjunctival treatment of IL-1ra has a significantly positive effect on promoting corneal allograft survival. And its effect is dosage-dependent.

MinK-related peptide 1: A beta subunit for the HCN ion channel subunit family enhances expression and speeds activation

The HCN family of ion channel subunits underlies the currents I(f) in heart and I(h) and I(q) in the nervous system. In the present study, we demonstrate that minK-related peptide 1 (MiRP1) is a beta subunit for the HCN family. As such, it enhances protein and current expression as well as accelerating the kinetics of activation. Because MiRP1 also functions as a beta subunit for the cardiac delayed rectifier I(Kr), these results suggest that this peptide may have the unique role of regulating both the inward and outward channels that underlie cardiac pacemaker activity. The full text of this article is available at http://www.circresaha.org.

Computerized planimetry versus clinical assessment for the measurement of cervical ectopia

OBJECTIVE

As part of a study to assess the role of cervical ectopia in the acquisition of cervical infections, we determined the reliability of cervical ectopia measurements made by computer planimetry and by clinical (visual) assessment.

STUDY DESIGN

We conducted pelvic examinations of 1004 women seeking contraceptive services at two health centers in Baltimore. After application of acetic acid, clinicians estimated the relative area of ectopia by visual inspection and took cervical photographs. Two independent raters measured the absolute and relative areas of ectopia from the digitized images by means of an analytic software program. Agreement levels between raters, between multiple readings by the same rater, and between the two measurement methods were quantified by means of the intraclass correlation coefficient and weighted kappa.

RESULTS

Intrarater agreement was excellent for computer planimetry measurements of the absolute (intraclass correlation coefficient, 0.97) and relative (intraclass correlation coefficient, 0.89) areas of ectopia. Interrater agreement was also high for computer planimetry measurements of the absolute (intraclass correlation coefficient, 0.83) and relative (intraclass correlation coefficient, 0.85) areas of ectopia. Agreement levels were moderate between clinician assessment and computer planimetry measurements of the relative area of ectopia (kappa = 0.48), but agreement was better when clinical assessment was limited to observations by a single, experienced clinician.

CONCLUSION

Measurement of cervical ectopia by computer planimetry was highly reliable and appears appropriate for assessment of the role of ectopia in the acquisition of cervical infections. Clinical assessment of cervical ectopia may be used when computer planimetry is not available.

Simultaneous quantitative UV spectrophotometric determination of multicomponents of amino acids using linear neural network

Simultaneous determination of multicomponents of six amino acids with a novel chemometric technique-a linear neural network (LNN) algorithm is reported in this study. Based on the data correlation coefficient and standard deviation method, 17 representative wavelength points are selected from the original UV spectral data (343 points) as the original input patterns for LNN to build a neural network model. The results obtained only by iterating 15 times is satisfying, with a correlation coefficient of 0.999 and a relative small standard deviation.

[Efficacy of topical cyclosporine A on keratoplasty rejection in rats]

OBJECTIVE

To evaluate the efficacy of topical cyclosporine A (CsA) on a penetrating keratoplasty rejection model in rats.

METHODS

Lou rats received orthotopic corneal allografts from inbred F344 donors. The rats were treated with one drop of topical solution four times daily for 30 days. Sixty rats were divided into one control (the matrix of CsA solution) and five treatment groups (0.5%, 1.0%, 2.0% CsA, glucocorticoid, glucocorticoid and 1.0% CsA). Rejection index (RI) and mean survival time (MST) were calculated, and histopathological and immunohistopathological examination were performed for each group.

RESULTS

The graft MST was postponed by topical CsA treatment. There was significant difference between each treatment group and the control group (t greater-than-or-equal 2.28, P < 0.0l), especially 2% CsA, steroid and combined 1% CsA and steroid groups, the combined group being the most effective. The RI was lower in all the groups with topical CsA than that in the control group (P < 0.01). The effect of 2% CsA was the same as that of the steroid, while 1% CsA combined steroid was the most effective. The histopathological findings confirmed that the topical application of CsA reduced the inflammatory cells infiltrating the graft stroma and the neovascularization. Immunohistopathological analysis demonstrated that there were fewer CD(+)(11a) T cells and macrophages in the infiltration and intercellular adhesion molecule (ICAM)-1 positive cells in keratocytes and endothelium of grafts in the treatment groups than in the control group.

CONCLUSIONS

Topical CsA can inhibit the keratoplasty rejection episodes in the rat and afford better results when combined with topical steroid.

Alternative splicing of KCNQ2 potassium channel transcripts contributes to the functional diversity of M-currents

The region of alternative splicing in the KCNQ2 potassium channel gene was determined by RNase protection analysis of KCNQ2 mRNA transcripts. Systematic analysis of KCNQ2 alternative splice variant expression in rat superior cervical ganglia revealed multiple variant isoforms. One class of KCNQ2 splice variants, those that contained exon 15a, was found to have significantly different kinetics to those of the other isoforms. These transcripts encoded channel subunits that, when co-expressed with the KCNQ3 subunit, activated and deactivated approximately 2.5 times more slowly than other isoforms. Deletion of exon 15a in these isoforms produced a reversion to the faster kinetics. Comparison of the kinetic properties of the cloned channel splice variants with those of the native M-current suggests that alternative splicing of the KCNQ2 gene may contribute to the variation in M-current kinetics seen in vivo.

[Ultrastructure changes of the olfactory epithelium of the patients suffering from dysosmia caused by the chronic sinusitis]

OBJECTIVE

To observe the ultrastructural changes of olfactory epithelium (OE) in patients suffering from dysosmia caused by chronic sinusitis.

METHODS

The specimens of olfactory epithelium were obtained from 35 patients operated for chronic sinusitis accompanied by dysosmia. According to the results of light microscope (LM) examination, the OE was divided into three groups by the types of pathological changes: normal, atrophic and respiratory epithelium metaplasia(REM). Transmission electron microscope was used to observe the ultrastructural changes of each group.

RESULTS

Under the LM, the surface ultrastructure of the OE showed some abnormal changes: (1) surface microvillus of the supporting cells disappeared; (2) olfactory vesicle changed their shape due to vacuolization; (3) disappearance of canaliculus structure in the olfactory vesicle; (4) the olfactory cilia changed the shape or reduced; some of the reduced cilia underwent metaplasia. The ultrastructural changes of atrophic OE included: (1) minor and moderate atrophy: the organelles and the membrane-limited electron dense vesicles on the upper section of the supporting cells obviously decreased or disappeared, even underwent vacuolization. The basic cell degenerated; (2) serious atrophy: the turbidity of the cell structure, even double cell structure, the nuclei of the cell aggregated as the plaque and vesiculose change or karyopyknosis. As for the cytoplasm, there were the dilation of the ERs, turgidity of the mitochondrion, the disarrangement, diminution and vacuolization. Fasciculate cilia were distributed separately in the REM group.

CONCLUSION

There is a positive relationship between the atrophy degree and the degree of the abnormal ultrastructural changes of the OE. The ultrastructural changes of OE in patients suffering from dysosmia caused by chronic sinusitis may provide reference for assessment of the treatment of dysosmia.