Oxidative stress response signaling pathways in trabecular meshwork cells and their effects on cell viability

PURPOSE

To clarify the primary oxidative stress response signaling pathways in trabecular meshwork (TM) cells and their effects on cell viability.

METHODS

Porcine TM cells were treated with 600 μM or 800 μM H₂O₂, and their time-dependent morphologic changes were observed. Phosphorylation of protein kinase B (Akt), extracellular regulated kinase (ERK)1/2, p38, and c-Jun NH2-terminal kinase (JNK) was evaluated by western blot analysis. The intracellular localization of NFκB was evaluated by western blot analysis. One-hour pretreatments with LY294002, U0126, and SB203580, with the inhibitors of PI3K, ERK1/2, and p38, respectively, were conducted to evaluate the roles of these molecules in the cellular reaction against H₂O₂. Cell viability was assessed using propidium iodide and anticleaved caspase-3 antibody.

RESULTS

TM cells treated with 600 μM H₂O₂ showed morphologic changes at 2 h that were partially recovered at 8 h after treatment. TM cells treated with 800 μM H₂O₂ did not recover, and the viability was significantly decreased. Both doses of H₂O₂ activated Akt, ERK1/2, and p38 in TM cells at 20 min after treatment, but not JNK or NFкB until 1 h after treatment. Inhibitors of PI3K, ERK1/2, and p38 suppressed recovery from the morphologic changes induced by 600 μM H₂O₂. Of these three inhibitors, the PI3K and ERK1/2 inhibitors decreased TM cell viability under oxidative stress.

CONCLUSIONS

In TM cells, the PI3K-Akt, ERK, and p38 signaling pathways are primary oxidative stress response pathways involved in the mechanism of recovery from cellular morphologic changes induced by H₂O₂ treatment accompanied by actin cytoskeletal changes.

[Five-year visual outcomes of typical age-related macular degeneration and/or polypoidal choroidal vasculopathy patients who received photodynamic therapy (PDT) as initial treatment in comparison with patients prior to the PDT era]

PURPOSE

To evaluate five-year visual outcomes of typical age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) in patients who received photodynamic therapy (PDT) as initial treatment compared with the outcomes of patients prior to the PDT era.

SUBJECTS AND METHODS

Twenty-three eyes observed for 5 years before PDT was available (group A: typical AMD/PCV 16 eyes/7 eyes) and 61 eyes which had been observed for 5 years after PDT with additional treatment as needed (group B: typical AMD/PCV 25 eyes/36 eyes). The visual changes in these groups were retrospectively compared.

RESULTS

In group A of typical AMD patients, the mean visual acuity (VA, logMAR) was significantly worse at the 3-year visit and later. In group B of typical AMD patients, the VA was stabilized after 2 years and no significant mean VA deterioration was observed for 5 years. More patients in group B retained a logMAR of less than 1.0 (43% vs. 25%) than in group A. Those patients in group B with PCV, maintained the VA for one year, but it gradually worsened thereafter.

CONCLUSION

The PDT shortened the duration of VA deterioration in typical AMD patients from 5 to 2 years with no significant VA decrease for 5 years. The positive effect of PDT on PCV eyes was temporary.

A case of wound dual infection with Pasteurella dagmatis and Pasteurella canis resulting from a dog bite -- limitations of Vitek-2 system in exact identification of Pasteurella species

Background

Pasteurella species, widely known as indigenous orgganisms in the oral and gastrointestinal floras of many wild and domestic animals, are important pathogens in both animals and humans. Human infections due to Pasteurella species are in most cases associated with infected injuries following animal bites. We encountered a rare case of dual infections caused by different two Pasteurella species occurred in a previously healthy 25-year-old female sustaining injury by a dog-bite.

Methodology

Exudates from the open wound of her dog-bite site, together with the saliva of the dog were submitted for bacteriological examination. Predominantly appearing grayish-white smooth colonies with almost the same colonial properties but slightly different glistening grown on chocolate and sheep blood agar plates were characterized morphologically by Gram's stain, biochemically by automated instrument using Vitek 2 system using GN cards together with commercially available kit system, ID-Test HN-20 rapid panels, and genetically by sequencing the 16S rRNA genes of the organism using a Taq DyeDeoxy Terminator Cycle Sequencing and a model 3100 DNA sequencer instrument.

Results

The causative isolates from the dog-bite site were finally identified as P. canis and P. dagmatis from the findings of the morphological, cultural, and biochemical properties together with the comparative sequences of the 16S rRNA genes. Both the isolates were highly susceptible to many antibiotics and the patient was successfully treated with the administration of so-called the first generation cephalosporin, cefazolin followed by so-called the third generation cephalosporin, cefcapene pivoxil. The isolate from the dog was subsequently identified as P. canis, the same species as the isolate from the patient.

Conclusions

To the best of our knowledge, this was the second report of a dual infection with Pasteurella species consisting of P. dagmatis and P. canis resulting from a dog-bite, followed by the first report of dual infections due to P. dagmatis and P. multocida in 1988. Our isolate finally identified as P. dagmatis was misidentified as P. pneumotripica by means of the Vitek 2 system. The species name "P. dagmatis" was not included in the database of the system. It is also important for routine clinical microbiology laboratories to know the limitation of the automated Vitek 2 system for the accurate identification of Pasteurella species especially P. dagmatis. It should be emphasized that there still exists much room for improvement in Vitek 2 system. Significant improvement of Vitek 2 system especially in the identification of Pasteurella species is urgently desired.

TET2 is essential for survival and hematopoietic stem cell homeostasis

Ten-Eleven-Translocation 2 (TET2) is an enzyme that catalyzes the conversion of 5-methylcytosine into 5-hydroxymethylcytosine (5-hmC) and thereby alters the epigenetic state of DNA; somatic loss-of-function mutations of TET2 are frequently observed in patients with diverse myeloid malignancies. To study the function of TET2 in vivo, we analyzed Ayu17-449 (TET2(trap)) mice, in which a gene trap insertion in intron 2 of TET2 reduces TET2 mRNA levels to about 20% of that found in wild-type (WT) mice. TET2(trap/trap) mice were born at Mendelian frequency but died at a high rate by postnatal day 3, indicating the essential role of TET2 for survival. Loss of TET2 results in an increase in the number of hematopoietic stem cells (HSCs)/progenitors in the fetal liver, and TET2(trap/trap) HSCs exhibit an increased self-renewal ability in vivo. In competitive transplantation assays, TET2(trap/trap) HSCs possess a competitive growth advantage over WT HSCs. These data indicate that TET2 has a critical role in survival and HSC homeostasis.

Lower plasma arginine in enteral tube-fed patients with pressure ulcer and improved pressure ulcer healing after arginine supplementation by Arginaid Water

OBJECTIVES

To determine the presence or extent of arginine deficiency in pressure ulcer (PU) patients on percutaneous endoscopic gastrostomy (PEG) feeding and to examine the effects of arginine supplementation on PU healing.

DESIGN

All eligible PEG patients, with and without PU, were cross-sectionally assessed for plasma arginine. Three-month supplementation with arginine-enriched water (Arginaid Water) was performed on a subset of patients with PU. This intervention study was a prospective, non-controlled trial with 5 PU patients.

SETTING

Geriatric ward of a rural clinical hospital in Japan.

PARTICIPANTS

Thirty-nine inpatients with PEG feeding were assessed for plasma arginine. Five of the 13 patients with PU and five of 26 patients without PU underwent amino acid profiling.

INTERVENTION

Five of the patients with PU received Arginaid Water supplementation.

MEASUREMENTS

Plasma amino acid measurements and biochemical analyses were performed. For those with PU on Arginaid Water supplementation, plasma arginine concentration and PU status were monitored every month.

RESULTS

Patients with PU showed significantly lower plasma arginine concentration compared to those without PU (control vs. PU; 80.2±21.3 vs 62.8±14.7 nmol/ml, p<0.01). After the addition of Arginaid Water, plasma arginine concentration increased (before vs 3 months later; 57.9±1.8 vs 83.1±8.5, p<0.01), and PU area, perimeter, DESIGN-R and PUSH scores significantly improved.

CONCLUSION

Plasma arginine was lower in PEG patients with PU. The healing rate of PU is improved with Arginaid Water supplementation. The findings from this study support the use of arginine supplementation in PEG patients with PU.