[The effect of the AIM2 inflammasome in noise-induced cognitive dysfunction in rats]

Objective: To explore the effect of the absent in melanoma 2 (AIM2) -mediated neuroinflammation in noise-induced cognitive dysfunction in rats. Methods: In April 2023, sixteen male Wistar rats were randomly divided into control group and noise group, with 8 rats in each group. The rats in the noise group were placed in 50 cm×50 cm×40 cm transparent boxes and exposed to 100 dB (A) white noise with a sound pressure level of 100 dB (A) (4 h/d for 30 d) . At the same time, rats in the control group were kept in similar boxes with environmental noise less than 60 dB (A) . After 30 days of noise exposure, the Morris water maze experiment was applied to test the learning and memory abilities of the rats; the pathological morphology of hippocampal tissues was observed by Hematoxylin-Eosin (HE) staining. Western blot was used to detect the protein expression levels of AIM2, cysteinyl aspartate specific proteinase-1 (caspase-1) , apoptosis-associated speck-like protein (ASC) , interleukin-1β (IL-1β) , IL-18, ionic calcium-binding articulation molecule-1 (Iba-1) , and glial fibrillary acidic protein (GFAP) . The expression of both Iba-1 and GFAP in hippocampal tissue was assessed by immunohistochemical staining. The co-localization of AIM2 with Iba-1 or GFAP was determined by immunofluorescence double staining. Results: Compared with the control group, the escape latency of rats in the noise group was increased by 16.29 s, 17.71 s, and 20.26 s on days 3, 4, and 5, respectively. On day 6, the noise-exposed rats spent shorter time in the target quadrant and had fewer times in crossing the platform[ (7.25±2.27) s and (1.13±0.64) times] than the control group[ (15.64±3.99) s and (4.25±2.12) times] (P<0.05) . After noise exposure, hippocampal neurons of rats displayed marked nuclear hyperchromatic and pyknosis phenomenon. The noise-exposed rats had higher numbers of both microglia and astrocytes (27.00±2.65 and 43.33±5.51) in the DG area of the hippocampus relative to the control group (14.67±3.06 and 20.00±4.58) (P<0.05) . Moreover, the glial cells in the noise group had larger cell cytosol with more and thicker branches. The protein expression levels of inflammatory cytokines Cleaved-IL-1β and Cleaved-IL-18 in the hippocampus of rats in the noise group (1.55±0.19 and 1.74±0.12) were significantly higher than the control group (1.00±0.11 and 1.00±0.13) (P<0.05) . After noise exposure, the protein expression levels of AIM2, Cleaved-Caspase-1 and ASC (1.19±0.09, 1.34±0.07 and 1.14±0.01) were higher than the control group (1.00±0.07, 1.00±0.14 and 1.00±0.06) and differences between the two groups were statistically significant (P<0.05) . A significant increase in the number of cells co-localizing AIM2 with Iba-1 or GFAP in the noise group (28.67±4.04 and 40.67±5.13) compared with the control group (15.67±4.04 and 17.67±3.79) , and statistically significant differences were observed between the two groups (P<0.05) . Conclusion: Noise exposure may activate the AIM2 inflammasome in hippocampal glial cells of rats, releasing excessive inflammatory cytokines and causing neuroinflammation that damages neurons.

Infection-activated lipopeptide nanotherapeutics with adaptable geometrical morphology for in vivo bacterial ablation

The nonselective membrane disruption of antimicrobial peptides (AMPs) helps in combating the antibacterial resistance. But their overall positive charges lead to undesirable hemolysis and toxicity toward normal living cells, as well as the rapid clearance from blood circulation. In consequence, developing smart AMPs to optimize the antimicrobial outcomes is highly urgent. Relying on the local acidity of microbial infection sites, in this work, we designed an acidity-triggered charge reversal nanotherapeutics with adaptable geometrical morphology for bacterial targeting and optimized therapy. C₁₆-A₃K₄-CONH₂ was proposed and the ε-amino groups in lysine residues were acylated by dimethylmaleic amide (DMA), enabling the generated C₁₆-A₃K₄(DMA)-CONH₂ to self-assemble into negatively charged spherical nanostructure, which relieved the protein adsorption and prolonged blood circulation in vivo. After the access of C₁₆-A₃K₄(DMA)-CONH₂ into the microbial infection sites, acid-sensitive β-carboxylic amide would hydrolyze to regenerate the positive C₁₆-A₃K₄-CONH₂ to destabilize the negatively charged bacterial membrane. In the meanwhile, attractively, the self-assembled spherical nanoparticle transformed to rod-like nanostructure, which was in favor of the efficient binding with bacterial membranes due to the larger contact area. Our results showed that the acid-activated AMP nanotherapeutics exhibited strong and broad-spectrum antimicrobial activities against Yeast, Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli, and methicillin-resistant Staphylococcus aureus (MRSA). Moreover, the biocompatible lipopeptide nanotherapeutics dramatically improved the dermapostasis caused by bacterial infection. The strategy of merging pathology-activated therapeutic function and morphological adaptation to augment therapeutic outcomes shows the great potential for bacterial inhibition. STATEMENT OF SIGNIFICANCE: The overall positive charges of antimicrobial peptides (AMPs) lead to undesirable hemolysis and nonselective toxicity, as well as the rapid clearance from blood circulation. Infection-activated lipopeptide nanotherapeutics with adaptable geometrical morphology were developed to address these issues. The self-assembled lipopeptide was pre-decorated to reverse the positive charge to reduce the hemolysis and nonselective cytotoxicity. After accessing the acidic infection sites, the nanotherapeutics recovered the positive charge to destabilize negatively charged bacterial membranes. Meanwhile, the morphology of self-assembled nanotherapeutics transformed from spherical nanoparticles to rod-like nanostructures in the lesion site, facilitating the improved association with bacterial membranes to boost the therapeutic efficiency. These results provide new design rationale for AMPs developed for bacterial inhibition.

Antibacterial and β-amyloid precursor protein-cleaving enzyme 1 inhibitory polyketides from the fungus Aspergillus chevalieri

One new prenylated benzenoid, (±)-chevalieric acid (1), and four new anthraquinone derivatives, (10S,12S)-, (10S,12R)-, (10R,12S)-, and (10R,12R)-chevalierone (2-5), together with ten previously described compounds (6-15), were isolated from the fungus Aspergillus chevalieri (L. Mangin) Thom and Church. The structures of new compounds were elucidated by extensive 1D and 2D nuclear magnetic resonance (NMR), and HRESIMS spectroscopic analysis. The absolute configurations of 2-5 were determined by experimental and calculated electronic circular dichroism (ECD) and DP4+ analysis. Compound 10 showed weak cytotoxicity against human lung cancer cell line A549 with IC50 39.68 μM. Compounds 2-5 exhibited antibacterial activities against the methicillin-resistant Staphylococcus aureus (MRSA) and opportunistic pathogenic bacterium Pseudomonas aeruginosa. The MIC value for compound 6 against MRSA is 44.02 μM. Additionally, Compounds 8, 10, 11 showed weak to moderate inhibitory activities against the β-secretase (BACE1), with IC50 values of 36.1, 40.9, 34.9 μM, respectively.

Experimental Limits on Exotic Spin and Velocity Dependent Interactions Using Rotationally Modulated Source Masses and an Atomic-Magnetometer Array

Various theories beyond the standard model predict new interactions mediated by new light particles with very weak couplings to ordinary matter. Interactions between polarized electrons and unpolarized nucleons proportional to g_{V}^{N}g_{A}^{e}σ[over →]·v[over →] and g_{A}^{N}g_{A}^{e}σ[over →]·v[over →]×r[over →] are two such examples, where σ[over →] is the spin of the electrons, r[over →] and v[over →] are position and relative velocity between the polarized electrons and nucleons, g_{V}^{N}/g_{A}^{N} is the vector or axial-vector coupling constant of the nucleon, and g_{A}^{e} is the axial-vector coupling constant of the electron. Such interactions involving a vector or axial-vector coupling g_{V}^{N}/g_{A}^{N} at one vertex and an axial-vector coupling g_{A}^{e} at the polarized electron vertex can be induced by the exchange of spin-1 bosons. We report new experimental upper limits on such exotic spin-velocity-dependent interactions of the electron with nucleons from dedicated experiments based on a recently proposed scheme. We rotationally modulated two ∼6  Kg source masses at a frequency of 20 Hz. We used four identical atomic magnetometers in an array form to increase the statistics and cancel the common-mode noise. We applied a data processing method based on high precision numerical integration for the four harmonic frequencies of the signal. We reverse the rotation direction of the source masses to flip the signal due to the new interactions; thus, we can apply the [+1,-3,+3,-1] weighting method to remove possible slow drifting. Our constraint on the product of vector and axial-vector couplings is |g_{V}^{N}g_{A}^{e}|<2.1×10^{-34} and on the product of axial-vector and axial-vector couplings is |g_{A}^{N}g_{A}^{e}|<2.4×10^{-22} for an interaction range of 10 m. The new constraints on vector-axial-vector interaction improved by as much as more than 4 orders of magnitude and on axial-axial interaction by as much as 2 orders of magnitude in the corresponding interaction range, respectively.

[The association between Cathepsin S and pulmonary function and CT phenotypes in patients with chronic obstructive pulmonary disease]

Objective: To explore the value of cathepsin S in the bronchoalveolar lavage fluid (BALF) of patients with chronic obstructive pulmonary disease (COPD) in the evaluation of pulmonary function and CT phenotypes. Method: From April 2014 to April 2017, 46 patients with stable COPD were enrolled, and 29 healthy volunteers served as the control group. The patients were divided into 4 subgroups: GOLD Ⅰ(n=12), GOLD Ⅱ(n=6), GOLD Ⅲ(n=14), GOLD Ⅳ(n=14). The levels of cathepsin S and IFN-γ in BALF were determined by enzyme-linked immunosorbent assay (ELISA). The percentage ratio of low attenuation area to total lung area (LAA%), two times the ratio of airway wall thickness to outer diameter(2T/D), and the ratio of wall area to total cross-sectional area (WA) were measured by HRCT. Results: There were significant differences in the levels of cathepsin S in BALF between the groups (F=6.639, P=0.000). BALF cathepsin S levels were as follows: GOLD Ⅳ grou P>GOLD Ⅲ grou P>GOLD Ⅱ grou P>GOLD group Ⅰ >healthy control group (P value were all<0.05); LAA grade 3>LAA grade 2>LAA grade 1>LAA grade 0 (P value were all<0.05). Correlation analysis showed that BALF cathepsin S levels were correlated negatively with FEV(1)/FVC, FEV(1)% predicted, and DLCO% (r value was -0.065、-0.576、-0.392, respectively, P value were all<0.05), and but positively with RV/TLC%, LAA%, 2T/D, WA and IFN-γ(r value was 0.695, 0.497, 0.142, 0.309, 0.148, respectively, P value were all<0.05). Conclusion: The levels of cathepsin S were associated with the degree of airflow limitation and emphysema phenotype in COPD.

Ring finger protein 145 (RNF145) is a ubiquitin ligase for sterol-induced degradation of HMG-CoA reductase

Cholesterol biosynthesis is tightly regulated in the cell. For example, high sterol concentrations can stimulate degradation of the rate-limiting cholesterol biosynthetic enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase, HMGCR). HMGCR is broken down by the endoplasmic reticulum membrane-associated protein complexes consisting of insulin-induced genes (Insigs) and the E3 ubiquitin ligase gp78. Here we found that HMGCR degradation is partially blunted in Chinese hamster ovary (CHO) cells lacking gp78 (gp78-KO). To identify other ubiquitin ligase(s) that may function together with gp78 in triggering HMGCR degradation, we performed a small-scale short hairpin RNA-based screening targeting endoplasmic reticulum-localized E3s. We found that knockdown of both ring finger protein 145 (Rnf145) and gp78 genes abrogates sterol-induced degradation of HMGCR in CHO cells. We also observed that RNF145 interacts with Insig-1 and -2 proteins and ubiquitinates HMGCR. Moreover, the tetrapeptide sequence YLYF in the sterol-sensing domain and the Cys-537 residue in the RING finger domain were essential for RNF145 binding to Insigs and RNF145 E3 activity, respectively. Of note, amino acid substitutions in the YLYF or of Cys-537 completely abolished RNF145-mediated HMGCR degradation. In summary, our study reveals that RNF145, along with gp78, promotes HMGCR degradation in response to elevated sterol levels and identifies residues essential for RNF145 function.

[Detection of Dickkopf-1 and alkaline phosphatase activity in gingival crevicular fluid from chronic periodontitis with Er:YAG laser as an adjunctive treatment]

PURPOSE

The aim of this study was to evaluate the clinical efficacy and the level of DKK1 and alkaline phosphatase (ALP) activity in gingival crevicular fluid (GCF) while taking Er:YAG laser as an adjunctive to scaling and root planning in the treatment of chronic periodontitis (CP).

METHODS

Eleven patients with CP were included and there were nineteen pairs of homonym teeth(thirty-eight teeth) in this split-mouth design, and they were randomly assigned to experimental group or control group. In the experimental group, a combination of ultrasonic subgingigval scaling and root planning with hand instrument (SRP) were performed with Er: YAG laser as an adjunctive; in the control group, only SRP was performed. The main variables were bleeding index (BI), probing depth (PD), clinical attachment loss (CAL) which were assessed at baseline (1 week after ultrasonic subgingival scaling), l month and 3 months after treatment. GCF was collected at baseline, l week, l month and 3 months, and the levels of DKK1 and ALP activity were detected at the same time point. The data were analyzed with SPSS 19.0 software package.

RESULTS

Both groups showed significant reduction of PD, CAL, BI values 1 month and 3months after treatment, but no significant difference in clinical parameters were found between the two groups. In the experimental group, the activity of ALP reduced to (386.69±146.42), (341.221±171.62), (249.27±98.72) from (396.191±150.55) U/L and the level of DKK1 dropped to (310.34±184.68), (270.04±55.14), (247.31±56.99) from (307.12±45.63) μg/L at the end of 1 week, 1 month, 3 months, respectively. Meanwhile, in the control group, the activity of ALP reduced to (374.72±131.27), (344.42±127.80), (252.36±90.4 ) from (394.09±120.25) U/L and the level of DKK1 dropped to (310.34±84.68), (270.04±55.14), (247.31±56.99) from (305.33±147.40) μg/L at the end of l week, l month, 3months, respectively. There is no significant difference between the two groups at any period for ALP or DKK1.

CONCLUSIONS

Er:YAG laser was a safe no-surgical adjunctive therapy in treating chronic periodontitis, further observation is needed to determine its long-term effectiveness.

High statistics measurement of the positron fraction in primary cosmic rays of 0.5-500 GeV with the alpha magnetic spectrometer on the international space station

A precision measurement by AMS of the positron fraction in primary cosmic rays in the energy range from 0.5 to 500 GeV based on 10.9 million positron and electron events is presented. This measurement extends the energy range of our previous observation and increases its precision. The new results show, for the first time, that above ∼200  GeV the positron fraction no longer exhibits an increase with energy.

First result from the Alpha Magnetic Spectrometer on the International Space Station: precision measurement of the positron fraction in primary cosmic rays of 0.5-350 GeV

A precision measurement by the Alpha Magnetic Spectrometer on the International Space Station of the positron fraction in primary cosmic rays in the energy range from 0.5 to 350 GeV based on 6.8 × 10(6) positron and electron events is presented. The very accurate data show that the positron fraction is steadily increasing from 10 to ∼ 250  GeV, but, from 20 to 250 GeV, the slope decreases by an order of magnitude. The positron fraction spectrum shows no fine structure, and the positron to electron ratio shows no observable anisotropy. Together, these features show the existence of new physical phenomena.

Multi-walled carbon nanotubes as a new counter electrode for dye-sensitized solar cells

Airbrushed multi-walled carbon nanotube (MWNT) networks were investigated as a new counter electrode for dye-sensitized TiO2 photoelectrochemical solar cells. The structural and physical properties of the MWNTs were studied by various techniques including SEM, TEM, Raman, optical absorption, and electrochemical impedance spectroscopy (EIS). The MWNTs exhibited catalytic activity for the reduction of triiodide in the electrolyte as studied by EIS measurements. The performance of the dye-sensitized solar cells was improved by using MWNTs as counter electrodes. This observation is explained by the significantly increased contact area between the MWNT counter electrode and the electrolyte which facilitates efficient charge transportation in the solar cell. We demonstrated that the MWNTs are suitable for replacing expensive Pt electrodes for fabricating high efficiency dye-sensitized solar cells. The process used in this study is also technically attractive for large scale and economic production.

Cell immobilization using PVA crosslinked with boric acid

A new cell immobilization technique is described in which polyvinyl alcohol is crosslinked with boric acid, with the addition of a small amount of calcium alginate. The presence of the calcium alginate improves the surface properties of the beads, preventing agglomeration. A pure culture of phenol-degrading Pseudomonas was immobilized in the PVA-alginate beads. Phenol was successfully degraded in a fluidized bed of the beads, indicating that cell viability was maintained following the immobilization procedure. The PVA-alginate beads proved to be very strong and durable, with no noticeable degradation of the beads after 2 weeks of continuous operation of the fluidized bed.

The association of clinical findings and exposure profiles with melamine associated nephrolithiasis

BACKGROUND

Little is known about the exposure profiles of melamine in children. We evaluated the association of clinical findings, exposure patterns and biomarkers with nephrolithiasis in children with potential exposure to melamine.

METHODS

A case-control study was conducted in children aged 0-16 years with potential exposure to contaminated dairy products. Cases were defined as nephrolithiasis detected by renal ultrasonography. On the basis of different brands of contaminated dairy products consumed, subjects were classified into high exposure, low exposure and control groups with estimated melamine exposure levels of higher than 2.5 ppm, 0.05-2.5 ppm and lower than detection limits <0.05 ppm. We measured urine melamine for those with nephrolithiasis and age-matched and gender-matched controls within the subset of the study population.

RESULTS

The duration of consumption of contaminated products was longer in children with nephrolithiasis in the high exposure group than in controls (median (IQR) 12.0 (3.3-24.0) vs 6.0 (4.0-7.0) months; p = 0.048). High melamine exposure levels were significantly associated with nephrolithiasis (OR 61.04 (95% CI 12.73 to 292.84)). The risk was found to increase with estimate melamine exposure levels (p for trend <0.001). Two among 10 affected subjects with nephrolithiasis showed elevated urine melamine levels. In comparison, levels of all 20 controls were lower than the detection limit.

CONCLUSIONS

The risk of melamine-associated nephrolithiasis was related to duration of consumption of contaminated products and estimated melamine exposure levels. Though urine melamine was not a sensitive test, it might serve as an exposure biomarker in melamine-associated nephrolithiasis.

Chromium (VI) induced oxidative damage to DNA: increase of urinary 8-hydroxydeoxyguanosine concentrations (8-OHdG) among electroplating workers

AIMS

To investigate the concentration of urinary 8-hydroxydeoxyguanosine (8-OHdG) among electroplating workers in Taiwan.

METHODS

Fifty workers were selected from five chromium (Cr) electroplating plants in central Taiwan. The 20 control subjects were office workers with no previous exposure to Cr. Urinary 8-OHdG concentrations were determined using high performance liquid chromatography with electrochemical detection.

RESULTS

Urinary 8-OHdG concentrations among Cr workers (1149.5 pmol/kg/day) were higher than those in the control group (730.2 pmol/kg/day). There was a positive correlation between urinary 8-OHdG concentrations and urinary Cr concentration (r = 0.447, p < 0.01), and urinary 8-OHdG correlated positively with airborne Cr concentration (r = 0.285). Using multiple regression analysis, the factors that affected urinary 8-OHdG concentrations were alcohol, the common cold, and high urinary Cr concentration. There was a high correlation of urinary 8-OHdG with both smoking and drinking, but multiple regression analysis showed that smoking was not a significant factor. Age and gender were also non-significant factors.

CONCLUSION

8-OHdG, which is an indicator of oxidative DNA damage, was a sensitive biomarker for Cr exposure.

Induction of cellular toxicity in cultured porcine corneal keratocytes by endothelin-1

The effect of endothelin-1 (ET-1) on corneal cells is not well understood. We investigated the biochemical changes of cultured porcine corneal keratocytes under exposure to ET-1. The results indicate that ET-1 has remarkable effects to inhibit corneal keratocytes on 3H-thymidine, 3H-leucine, 3H-uridine uptakes and cellular migration. It is in a dose-dependent manner at concentrations ranging from 10(-7) M to 10(-9) M. The 50% inhibitory dose (ID50) for ET-1, as measured by 3H-thymidine uptake, 3H-uridine uptake and 3H-leucine uptake, were 10(-7) M, 10(-0.52) M and 10(-11.8) M, respectively. The dead and living cells were estimated with MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay that was converted tetrazolium dye of living cells only into insoluble purple formazan crystals within mitochondria. In the presence of ET-1, the cellular MTT values were also decreased. The ID50 for ET-1 with cell migration assay and MTT assay were measured at 10(-7.86) M and 10(-5.1) M. Endothelin-1 (10(-6) M) promptly changed cellular morphology and attenuated adhesion observed with laser scanning cytometer. Endothelin-1-induced characteristic apoptosis cells were observed using a TUNEL assay that detected fragmented DNA of apoptosis. Western blot assay revealed that endothelin-1 induced proteolysis and decreased in fibronectin protein. These findings indicate that endothelin-1 may lead keratocytes to death resulting from induction of apoptosis and functional loss.

Tentative surgical repair of leaking filtering bleb with amniotic membrane transplantation--a case report

To repair a traumatic leaking cystic bleb in a 50-year-old male patient who had received multiple glaucoma filtering surgeries with the application of mitomycin-C, an amniotic membrane covered over the leaking bleb and sutured it to the adjacent conjunctiva with 10-0 nylon was done. The anterior chamber gradually formed after the amniotic membrane transplantation (AMT) and intraocular pressure returned to the level before trauma. Three weeks after the operation, the amniotic membrane was removed. No more leakage from the bleb was observed during four months follow-up. However, another bleb revision surgery was performed later to repair recurrent bleb leakage. Although conjunctival advancement or free conjunctival autograft have been reported to repair leaking bleb successfully, the simple primary method of using AMT is still encouraged in repair of a ruptured bleb with tentative maintenance of adequate filtration.

Toxic effects of mitomycin-C on cultured ciliary process cells and trabecular meshwork cells

Mitomycin-C has recently become an adjunct medication for inhibition of fibroblast proliferation in glaucoma filtering procedures. Prolonged postoperative ocular hypotony has been a frequent complication of trabeculectomy with mitomycin-C. In order to characterize the hypotony mechanism, we compared the toxic effects of mitomycin-C on cultured rabbit ciliary process cells and trabecular meshwork cells. The results indicate that mitomycin-C has a more marked effect on ciliary process cells on 3H-thymidine uptake than on trabecular meshwork cells at concentrations ranging from 10(-1) to 10(-5) mg/ml after 3-, 5- and 60-min treatment, respectively. The living cells after mitomycin-C treatment were estimated with MTT assay that was converted tetrazolium dye of living cells only into insoluble purple formazan crystals within mitochondria. In the presence of mitomycin-C for 3, 5, and 60 min, the cellular MTT values in ciliary process cells were more decreased than in trabecular meshwork cells. Depolarization of the trabecular meshwork cells with 50 mM KCl led to an increase in intracellular calcium concentration, whereas application of mitomycin-C at 10(-3) mg/ml resulted in decrease of KCl-induced intracellular calcium increase. Mitomycin-C (10(-3) mg/ml) decreased cAMP concentration in ciliary process cells following 3- and 5-min treatment; however, it did not significantly affect the cellular cAMP concentration after only a 1-min exposure. Mitomycin-induced marked ladder pattern of DNA fragmentation was observed in ciliary process tissues after treatment with 10(-1) mg/ml of mitomycin-C for 3 and 5 min. However, the DNA pattern in trabecular meshwork tissues was not obviously affected by mitomycin-C. These findings from our results indicate that mitomycin-induced ocular hypotony may result from damage to both ciliary process and trabecular meshwork tissues.

Endothelin-induced changes of secondary messengers in cultured corneal endothelial cells

The effect of endothelins on corneal endothelial cells is not well understood. We have investigated the effects of endothelin-1 (ET-1), endothelin-2 (ET-2) and endothelin-3 (ET-3) on bovine corneal endothelial cellular proliferation and the secondary messenger changes in cells in the presence of ET-1. It was found that the 3H-thymidine uptake was enhanced by ET-1 significantly, whereas ET-2 and ET-3 had no effect. ET-1 remarkably affects the increase of corneal endothelial cells on 3H-thymidine, 3H-leucine, and 3H-uridine uptakes in a dose-dependent manner. The 50% effective concentrations (EC50) for ET-1, as measured by 3H-thymidine uptake, 3H-uridine uptake, and 3H-leucine uptake were 10(-8.78) M, 10(-8.53) M and 10(-8.04) M, respectively. It was found that endothelin-1 increased intracellular calcium concentration by using the method of preloading with Fura-2-AM and assaying with spectrophotometry. The cellular IP1, IP2, and IP3 were also stimulated in the presence of ET-1. Moreover, ET-1 enhanced the basal cellular cAMP and cGMP concentrations in corneal endothelial cells in a dose-dependent manner. Immunofluorescent staining revealed that ET-1 increased the fibronectin protein concentration and changed protein distribution in corneal endothelial cells. These findings indicate that endothelin-1 increases in cell proliferation and biological changes may be involved in changing intracellular calcium mobility, increasing intracellular phosphoinositides, enhancing intracellular cGMP and cAMP accumulation, and fibronectin protein synthesis.

Herniated blastomere following chemically assisted hatching may result in monozygotic twins

OBJECTIVE

To explore a possible mechanism of the increasing incidence of monozygotic twins following assisted hatching of human embryos.

DESIGN

Case report.

SETTING

Clinical research center in a medical school teaching hospital.

PATIENT

A 37-year-old infertile woman with repeated IVF failures.

INTERVENTION(S)

Assisted hatching of the day 3 embryos using acidic Tyrode's solution.

MAIN OUTCOME MEASURE(S)

The morphology of the zona-drilled embryos and the pregnancy outcome.

RESULT(S)

After assisted hatching, a herniated blastomere through an oversized opening in the zona pellucida was found in one embryo. The transfer of two zona-drilled embryos resulted in a triplet pregnancy.

CONCLUSION(S)

Large openings in the zona pellucida following chemically assisted hatching may cause premature hatching of the blastomeres and may be implicated in the occurrence of monozygotic twins.

Effects of drugs on cellular proliferation in cultured iris pigment epithelial cells and retinal pigment epithelial cells

In this study, iris and retinal pigment epithelial cells were cultured from porcine and various drugs including methionine-enkephalin, isoproterenol, dibutyryl cAMP, endothelin-1, dexamethasone and phorbol 12-myristate 13-acetate (PMA) were used to investigate their effects on both cellular proliferation in cultured porcine iris and retinal pigment epithelial cells. Cellular proliferation was estimated with 3H-thymidine uptake. It is indicated that both pigment epithelial cells possess epithelial-like morphology and abundant pigment granules in cells obviously. Following the iris pigment epithelial cells being treated with endothelin-1, the 3H-thymidine uptake in the cells was increased to 126% as compared with the control. However, the cellular proliferation was decreased to 83% when the cells were treated with isoproterenol. In the case of methionine-enkephalin, dibutyryl cAMP, dexamethasone and phorbol 12-myristate 13-acetate (PMA), the thymidine uptake in the iris pigment epithelial cells was not affected by above drugs. In the retinal pigment epithelial cells, the 3H-thymidine uptakes were increased to 145% and 146% when the cells were incubated with methionine-enkephalin, and isoproterenol, respectively. In the presence of dibutyryl cAMP, dexamethasone and phorbol ester (PMA), the cellular proliferation was inhibited to 83%, 73% and 85% respectively. However, endothelin-1 did not affect the cellular proliferation in retinal pigment epithelial cells. These results show that the morphological shapes of iris pigment epithelial cells are similar to retinal pigment epithelial cells. However, the cellular proliferation in both cells may be regulated by distinct mechanisms.

Biomarkers of exposure and effect as indicators of potential carcinogenic risk arising from in vivo metabolism of ethylene to ethylene oxide

The purposes of the present study were: (i) to investigate the potential use of several biomarkers as quantitative indicators of the in vivo conversion of ethylene (ET) to ethylene oxide (EO); (ii) to produce molecular dosimetry data that might improve assessment of human risk from exogenous ET exposures. Groups (n = 7/group) of male F344 rats and B6C3F1 mice were exposed by inhalation to 0 and 3000 p. p.m. ET for 1, 2 or 4 weeks (6 h/day, 5 days/week) or to 0, 40, 1000 and 3000 p.p.m. ET for 4 weeks. N:-(2-hydroxyethyl)valine (HEV), N:7-(2-hydroxyethyl) guanine (N7-HEG) and HPRT: mutant frequencies were assessed as potential biomarkers for determining the molecular dose of EO resulting from exogenous ET exposures of rats and mice, compared with background biomarker values. N7-HEG was quantified by gas chromatography coupled with high resolution mass spectrometry (GC-HRMS), HEV was determined by Edman degradation and GC-HRMS and HPRT: mutant frequencies were measured by the T cell cloning assay. N7-HEG accumulated in DNA with repeated exposure of rodents to 3000 p.p.m. ET, reaching steady-state concentrations around 1 week of exposure in most tissues evaluated (brain, liver, lung and spleen). The dose-response curves for N7-HEG and HEV were supralinear in exposed rats and mice, indicating that metabolic activation of ET was saturated at exposures >/=1000 p.p.m. ET. Exposures of mice and rats to 200 p.p.m. EO for 4 weeks (as positive treatment controls) led to significant increases in HPRT: mutant frequencies over background in splenic T cells from exposed rats and mice, however, no significant mutagenic response was observed in the HPRT: gene of ET-exposed animals. Comparisons between the biomarker data for both unexposed and ET-exposed animals, the dose-response curves for the same biomarkers in EO-exposed rats and mice and the results of the rodent carcinogenicity studies of ET and EO suggest that too little EO arises from exogenous ET exposure to produce a significant mutagenic response or a carcinogenic response under standard bioassay conditions.

Change of calcium and cAMP concentration by adrenoceptor agents in cultured porcine corneal endothelial cells

It has been reported that beta-adrenergic receptors are localized in the corneal endothelial cells. In this study, the change of cellular signal transduction, such as intracellular calcium and cAMP, was determined with pure adrenergic agonists and commercial antiglaucoma adrenergic agents. The intracellular calcium of cultured porcine corneal endothelial cells was inhibited by 10 microM isoproterenol and norepinephrine, but enhanced by propranolol and 50 mM KCl. In the case of phenylephrine, calcium mobility did not alter significantly. Verapamil, at 10 microM, decreased intracellular calcium concentration. In the presence of isoproterenol, cellular cAMP concentration increased from 28.8 pmole/mg protein (1 microM) to 42.2 pmole/mg protein (100 microM) compared with control of 6.07 pmole/mg protein. Incubation with commercial adrenergic eye drops, such as betaxolol, caused the cAMP concentration to increase from 21.6 pmole/mg protein (0.0005%) to 39.1 pmole/mg protein (0.05%). Adding commercial levobunolol and timolol into cells caused cellular cAMP to increase from 14.3 pmole/mg protein (0.0005%) to 840.5 pmole/mg protein (0.05%) and from 115.2 pmole/mg protein (0.00025%) to 931.0 pmole/mg protein (0.025%), respectively. However, the preservative, benzalkonium chloride, increased cellular cAMP from 15.4 pmole/mg protein (0.00001 mg/ml) to 1087.4 pmole/mg protein (0.01 mg/ml). It is concluded that the intracellular calcium of corneal endothelium decreases when the cellular adrenergic receptor is activated by agonists. Benzalkonium chloride, due to its preservative in commercial antiglaucoma agents which increases cellular cAMP, may alter corneal endothelial physiology through long-term use.

Corticosteroid dynamics in the nonpregnant, pregnant, and postpartum spontaneously hypertensive rat

Factors responsible for hypertension in the spontaneously hypertensive rat (SHR) remain under investigation. As in human pregnancy complicated by essential chronic hypertension, the hypertension of the pregnant SHR subsides and returns postpartum. Because corticosteroid excess can cause hypertension, we examined several aspects of adrenocortical activity as potentially affecting the reported blood pressure profiles of nonpregnant, term pregnant, and postpartum SHR, using normotensive Wistar-Kyoto (WKY) rats as controls. We found that corticosterone levels were comparable in nonpregnant SHR and WKY rats, and unaffected by pregnancy. No differences were detected postpartum. Although pregnancy was accompanied by significant increases in plasma aldosterone levels, no interbreed differences were observed, which remained the case postpartum. Single adrenal cell secretion of aldosterone and corticosterone, as detected by reverse hemolytic plaque assay, yielded similar results in the pregnant and postpartum rat. Hormone responses to dietary manipulations in the nonpregnant and pregnant SHR and WKY suggest an important role for ACTH, and a lesser one for AII in the regulation of corticosteroids. In situ hybridization histochemistry, using a probe that detects both P450c11beta and P450c11AS mRNA, revealed comparable message density and zonal distribution in adrenals from pregnant and nonpregnant SHR and WKY rats. Breed- and pregnancy-dependent differences in adrenal expression of P450scc, P450c11beta, and P450c11AS were noted. In summary, our findings suggest that although some discrepancies exist in the aspects of adrenocortical activity examined, they are unlikely to be etiologic in the blood pressure profile observed in nonpregnant, pregnant, and postpartum SHR.