Aquaporin 0 plays a pivotal role in refractive index gradient development in mammalian eye lens to prevent spherical aberration

Aquaporin 0 (AQP0) is a transmembrane channel that constitutes ∼45% of the total membrane protein of the fiber cells in mammalian lens. It is critical for lens transparency and homeostasis as mutations and knockout cause autosomal dominant lens cataract. AQP0 functions as a water channel and as a cell-to-cell adhesion (CTCA) molecule in the lens. Our recent in vitro studies showed that the CTCA function of AQP0 could be crucial to establish lens refractive index gradient (RING). However, there is a lack of in vivo data to corroborate the role of AQP0 as a fiber CTCA molecule which is critical for creating lens RING. The present investigation is undertaken to gather in vivo evidence for the involvement of AQP0 in developing lens RING. Lenses of wild type (WT) mouse, AQP0 knockout (heterozygous, AQP0^+/−) and AQP0 knockout lens transgenically expressing AQP1 (heterozygous AQP0^+/−/AQP1^+/−) mouse models were used for the study. Data on AQP0 protein profile of intact and N- and/or C-terminal cleaved AQP0 in the lens by MALDI-TOF mass spectrometry and SDS–PAGE revealed that outer cortex fiber cells have only intact AQP0 of ∼28 kDa, inner cortical and outer nuclear fiber cells have both intact and cleaved forms, and inner nuclear fiber cells have only cleaved forms (∼26–24 kDa). Knocking out of 50% of AQP0 protein caused light scattering, spherical aberration (SA) and cataract. Restoring the lost fiber cell membrane water permeability (P_f) by transgene AQP1 did not reinstate complete lens transparency and the mouse lenses showed light scattering and SA. Transmission and scanning electron micrographs of lenses of both mouse models showed increased extracellular space between fiber cells. Water content determination study showed increase in water in the lenses of these mouse models. In summary, lens transparency, CTCA and compact packing of fiber cells were affected due to the loss of 50% AQP0 leading to larger extracellular space, more water content and SA, possibly due to alteration in RING. To our knowledge, this is the first report identifying the role of AQP0 in RING development to ward off lens SA during focusing.     

Unraveling aquaporin interaction partners

Background

Insight into protein–protein interactions (PPIs) is highly desirable in order to understand the physiology of cellular events. This understanding is one of the challenges in biochemistry and molecular biology today, especially for eukaryotic membrane proteins where hurdles of production, purification and structural determination must be passed.

Scope of review

We have explored the common strategies used to find medically relevant interaction partners of aquaporins (AQPs). The most frequently used methods to detect direct contact, yeast two-hybrid interaction assay and co-precipitation, are described together with interactions specifically found for the selected targets AQP0, AQP2, AQP4 and AQP5.

Major conclusions

The vast majority of interactions involve the aquaporin C-terminus and the characteristics of the interaction partners are strikingly diverse. While the well-established methods for PPIs are robust, a novel approach like bimolecular fluorescence complementation (BiFC) is attractive for screening many conditions as well as transient interactions. The ultimate goal is structural evaluation of protein complexes in order to get mechanistic insight into how proteins communicate at a molecular level.

General significance

What we learn from the human aquaporin field in terms of method development and communication between proteins can be of major use for any integral membrane protein of eukaryotic origin. This article is part of a Special Issue entitled Aquaporins.     

Association between -251A>T polymorphism in the interleukin-8 gene and oral cancer risk: A meta-analysis

Background

Emerging evidence showed that the most common functional polymorphism (-251A>T, rs4073) in the promoter region of the interleukin-8 (IL-8) gene is involved in the regulation of the activities of interleukin-8, thus increasing an individual's susceptibility to oral cancer; but individually published results are inconclusive. The aim of this meta-analysis was to investigate the associations between IL-8 -251A>T polymorphism and oral cancer risk.

Methods

The PubMed, Embase, Web of Science and CBM databases were searched for all articles published up to October 1st, 2012 that addressed IL-8 -251A>T polymorphism and oral cancer risk. Statistical analyses were performed using STATA 12.0 software. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations.

Results

Six case–control studies were included with a total of 1324 oral cancer cases and 1879 healthy controls. When all available studies were pooled into the meta-analysis, the results showed that the AA and AT genotypes of IL-8 -251A>T polymorphism were associated with increased risk of oral cancer (OR = 1.23, 95% CI: 1.03–1.46, P = 0.025; OR = 1.25, 95% CI: 1.07–1.47, P = 0.006; respectively). In the subgroup analysis by ethnicity, significant associations were observed between the AA and AT genotypes of IL-8 -251A>T polymorphism and increased risk of oral cancer among Caucasian populations (OR = 1.40, 95% CI: 1.14–1.72, P = 0.001; OR = 1.29, 95% CI: 1.06–1.57, P = 0.011; respectively). However, no statistically significant associations were found between IL-8 -251A>T polymorphism and oral cancer risk among Asian populations.

Conclusions

Results from the current meta-analysis indicate that the AA and AT genotypes of IL-8 -251A>T polymorphism might increase the risk of oral cancer, especially among Caucasian populations.     

Propylisopropylacetic acid (PIA), a constitutional isomer of valproic acid,uncompetitively inhibits arachidonic acid acylation by rat acyl-CoA synthetase 4: A potential drug for bipolar disorder

Background

Mood stabilizers used for treating bipolar disorder (BD) selectively downregulate arachidonic acid (AA) turnover (deacylation–reacylation) in brain phospholipids, when given chronically to rats. In vitro studies suggest that one of these, valproic acid (VPA), which is teratogenic, reduces AA turnover by inhibiting the brain long-chain acyl-CoA synthetase (Acsl)4 mediated acylation of AA to AA-CoA. We tested whether non-teratogenic VPA analogues might also inhibit Acsl4 catalyzed acylation, and thus have a potential anti-BD action.

Methods

Rat Acsl4-flag protein was expressed in Escherichia coli, and the ability of three VPA analogues, propylisopropylacetic acid (PIA), propylisopropylacetamide (PID) and N-methyl-2,2,3,3-tetramethylcyclopropanecarboxamide (MTMCD), and of sodium butyrate, to inhibit conversion of AA to AA-CoA by Acsl4 was quantified using Michaelis–Menten kinetics.

Results

Acsl4-mediated conversion of AA to AA-CoA in vitro was inhibited uncompetitively by PIA, with a K_i of 11.4 mM compared to a published K_i of 25 mM for VPA, while PID, MTMCD and sodium butyrate had no inhibitory effect.

Conclusions

PIA's ability to inhibit conversion of AA to AA-CoA by Acsl4 in vitro suggests that, like VPA, PIA may reduce AA turnover in brain phospholipids in unanesthetized rats, and if so, may be effective as a non-teratogenic mood stabilizer in BD patients.     

Association of functional FEN1 genetic variants and haplotypes and breast cancer risk

Aim

As a tumor suppressor, FEN1 plays an essential role in preventing tumorigenesis. Two functional germline variants (-69G > A and 4150G > T) in the FEN1 gene have been associated with DNA damage levels in coke-oven workers and multiple cancer risk in general populations. However, it is still unknown how these genetic variants are involved in breast cancer susceptibility.

Methods

We investigated the association between these polymorphisms and breast cancer risk in two independent case–control sets consisted of a total of 1100 breast cancer cases and 1400 controls. The influence of these variations on FEN1 expression was also examined using breast normal tissues.

Results

It was found that the FEN1-69GG genotypes were significantly correlated to increased risk for developing breast cancer compared with the -69AA genotype in both sets [Jinan set: odds ratios (OR) = 1.41, 95% confidence interval (CI) = 1.20–1.65, P = 1.9×10^− 5; Huaian set: OR = 1.51, 95% CI = 1.22–1.86, P = 1.7×10^− 4]. Similar results were observed for 4150G > T polymorphism. The genotype–phenotype correlation analyses demonstrated that the -69G or 4150G allele carriers had more than 2-fold decreased FEN1 expression in breast tissues compared with -69A or 4150T carriers, suggesting that lower FEN1 expression may lead to higher risk for malignant transformation of breast cells.

Conclusion

Our findings highlight FEN1 as an important gene in human breast carcinogenesis and genetic variants in FEN1 confer susceptibility to breast cancer.     

Aquaporin and brain diseases

Background

The presence of water channel proteins, aquaporins (AQPs), in the brain led to intense research in understanding the underlying roles of each of them under normal conditions and pathological conditions.

Scope of review

In this review, we summarize some of the recent knowledge on the 3 main AQPs (AQP1, AQP4 and AQP9), with a special focus on AQP4, the most abundant AQP in the central nervous system.

Major conclusions

AQP4 was most studied in several brain pathological conditions ranging from acute brain injuries (stroke, traumatic brain injury) to the chronic brain disease with autoimmune neurodegenerative diseases. To date, no specific therapeutic agents have been developed to either inhibit or enhance water flux through these channels. However, experimental results strongly underline the importance of this topic for future investigation. Early inhibition of water channels may have positive effects in prevention of edema formation in brain injuries but at later time points during the course of a disease, AQP is critical for clearance of water from the brain into blood vessels.

General significance

Thus, AQPs, and in particular AQP4, have important roles both in the formation and resolution of edema after brain injury. The dual, complex function of these water channel proteins makes them an excellent therapeutic target. This article is part of a Special Issue entitled Aquaporins.     

Association between resistin + 299A/A genotype and nonalcoholic fatty liver disease in Chinese patients with type 2 diabetes mellitus

Objective

To investigate the relationship between the resistin intronic + 299G/A polymorphism and nonalcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes mellitus (T2DM).

Methods

We selected 738 T2DM patients, including 395 with NAFLD and 343 without fatty liver disease, as well as 279 healthy control individuals, and analyzed their resistin + 299G/A polymorphism genotype by polymerase chain reaction–restriction fragment length polymorphism.

Results

Plasma resistin levels in T2DM patients with NAFLD were at the highest (P < 0.05). The frequency of AA genotype at the + 299 site of the resistin gene in patients with concurrent T2DM combined with NAFLD was significantly different from that in the control (P < 0.05). The AA genotype was found to be associated with a 1.80-fold increased risk for T2DM combined with NAFLD, 2.05-fold increased risk for obesity and 2.37-fold increased risk for obesity of abdominal type compared to the GG (P < 0.05, respectively). The multivariate non-conditional logistic regression model analysis further shows that the AA genotype is a risk factor for the development of NAFLD in T2DM patients (OR, 2.32; 95% CI, 1.05–4.68; P < 0.05).

Conclusion

The resistin + 299AA genotype may be associated with increases in the risk of the NAFLD development in T2DM patients.     

Relationship between CCR2-V64I polymorphism and cancer risk: A meta-analysis

Background and objectives

The role of CCR2-V64I polymorphism in various cancers has been reported in many studies. However, results from published studies on the association between CCR2-V64I polymorphism and cancer risk are conflicting. Therefore, we performed a meta-analysis to estimate the overall cancer risk associated with the polymorphism.

Methods

Electronic searches of PubMed and EMBASE were conducted for all publications on the association between this variant and cancer. Odds ratios (OR) with 95% confidence intervals (95% CI) were used to access the strength of this association.

Results

Sixteen studies with 2661 cancer patients and 5801 healthy controls were included. Overall, significant association was found between the CCR2-V64I polymorphism and cancer risk (OR = 1.84, 95% CI = 1.35–2.51, AA vs GA/GG, P = 0.37). In the subgroup analysis stratified by cancer types, there was a significant association between this polymorphism and bladder cancer (OR = 2.06, 95% CI = 1.02–4.15, AA vs GA/GG, P = 0.11), cervical cancer (OR = 3.34, 95% CI = 1.48–7.50, AA vs GG, P = 0.56), and oral cancer (OR = 2.04, 95% CI = 1.46–2.84, GA vs GG, P = 0.70). In the subgroup analysis stratified by ethnicities, an increased cancer risk was also found in Europeans (OR = 2.31, 95% CI = 1.45–3.68, AA vs GA/GG, P = 0.16) and Asians (OR = 1.88, 95% CI = 1.12–3.16, AA vs GA/GG, P = 0.92).

Conclusion

This meta-analysis suggested that CCR2-V64I polymorphism may contribute to an increased risk of cancer.     

Water channel structures analysed by electron crystallography

Background

The mechanisms underlying water transport through aquaporin (AQP) have been debated for two decades. The water permeation phenomenon of AQP seems inexplicable because the Grotthuss mechanism does not allow for simultaneous fast water permeability and inhibition of proton transfer through the hydrogen bonds of water molecules.

Scope of review

The AQP1 structure determined by electron crystallography provided the first insights into the proton exclusion mechanism despite fast water permeation. Although several studies have provided clues about the mechanism based on the AQP structure, each proposed mechanism remains incomplete. The present review is focused on AQP function and structure solved by electron crystallography in an attempt to fill the gaps between the findings in the absence and presence of lipids.

Major conclusions

Many AQP structures can be superimposed regardless of the determination method. The AQP fold is preserved even under conditions lacking lipids, but the water arrangement in the channel pore differs. The differences might be explained by dipole moments formed by the two short helices in the lipid bilayer. In addition, structure analyses of double-layered two-dimensional crystals of AQP suggest an array formation and cell adhesive function.

General significance

Electron crystallography findings not only have contributed to resolve some of the water permeation mechanisms, but have also elucidated the multiple functions of AQPs in the membrane. The roles of AQPs in the brain remain obscure, but their multiple activities might be important in the regulation of brain and other biological functions. This article is part of a Special Issue entitled Aquaporins.     

The association between Interleukin (IL)-4 gene intron 3 VNTR polymorphism and alopecia areata (AA) in Turkish population

Objective

Alopecia areata (AA) is hypothesized to be an organ-specific autoimmune disease of hair follicles mediated by T cells. As immunological and genetic factors have been implicated in the pathogenesis of AA, the purpose of the present study was to investigate possible associations between the functional Interleukin (IL)-4 gene intron 3 VNTR polymorphism and AA susceptibility and disease progression in Turkish population.

Methods

The study group consisted of 116 unrelated patients with AA and 125 unrelated healthy controls. Genomic DNA was isolated and IL-4 gene 70 bp VNTR polymorphism determined by using polymerase chain reaction (PCR) with specific primers.

Results

No association was observed between AA patients and controls according to genotype distribution (p = 0.051). The allele distribution of IL-4 gene intron 3 VNTR polymorphism was statistically different between AA patients and control group (p = 0.026). The frequency of P1 allele in patients was significantly higher than that in the control group. When the P2P2 genotype was compared with P1P2 + P1P1 genotypes, a statistically significant difference was observed between patients and controls (p = 0.036). Intron 3 VNTR polymorphism in the IL-4 gene was found to be associated with AA susceptibility in Turkish population.

Conclusion

The results suggest that IL-4 VNTR polymorphism in the intron 3 region may be a risk factor for the development of AA among Turkish population. This is the first to report that intron 3 VNTR polymorphism in the IL-4 gene is associated with AA susceptibility.     

A pentapeptide signature motif plays a pivotal role in Leishmania DNA topoisomerase IB activity and camptothecin sensitivity

Background

Leishmania donovani – the causative agent of visceral leishmaniasis – has several evolutionary characteristics that make the disease difficult to combat. Among these differences, a rare heterodimeric DNA topoisomerase IB has been reported thus opening a new promising field in the therapy of leishmaniasis. Several studies of the human enzyme have pointed to the importance of the linker domain in respect to camptothecin sensitivity. At present, it has been impossible to pinpoint the regions that make up the linker domain in Leishmania.

Methods

Several site-directed mutations as well as internal and linear truncations involving both subunits were assayed on both, relaxation activity and sensitivity to camptothecin.

Results

Truncations performed on the trypanosomatids conserved motif (RPPVVRS) of the small subunit of leishmanial DNA topoisomerase IB demonstrated that elimination of pentapeptide RPPVV produced a nonfunctional enzyme. However, the removal of the dipeptide RS led to an enzyme with reduced relaxation activity and less sensitivity to camptothecin. The basic structure, both sensitive to camptothecin and able to fully relax DNA, composed of amino acids 1–592 and 175–262 in the large and small subunits, respectively.

Conclusion

It has been established that the region between amino acids 175 and 180 (RPPVV) of the small subunit plays a pivotal role in both interaction with the large subunit and sensitivity to camptothecin in Leishmania.

General significance

The present report describes a functional analysis of the leishmanial DNA topoisomerase IB regions directly involved both in sensitivity to poisons and in the conformation of the linker domain.     

Melatonin renders neuroprotection by protein kinase C mediated aquaporin-4 inhibition in animal model of focal cerebral ischemia

Aim

Aquaporin-4(AQP4) expression in the brain with relation to edema formation following focal cerebral ischemia was investigated. Studies have shown that brain edema is one of the significant factors in worsening stroke outcomes. While many mechanisms may aggravate brain injury, one such potential system may involve AQP4 up regulation in stroke patients that could result in increased edema formation. Post administration of melatonin following ischemic stroke reduces AQP4 mediated brain edema and confers neuroprotection.

Materials and methods

An in-silico approach was undertaken to confirm effective melatonin-AQP4 binding. Rats were treated with 5 mg/kg, i.p. melatonin or placebo at 30 min prior, 60 min post and 120 min post 60 min of middle cerebral artery occlusion (MCAO) followed by 24 h reperfusion. Rats were evaluated for battery of neurological and motor function tests just before sacrifice. Brains were harvested for infarct size estimation, water content measurement, biochemical analysis, apoptosis study and western blot experiments.

Key findings

Melatonin at 60 min post ischemia rendered neuroprotection as evident by reduction in cerebral infarct volume, improvement in motor and neurological deficit and reduction in brain edema. Furthermore, ischemia induced surge in levels of nitrite and malondialdehyde (MDA) were also found to be significantly reduced in ischemic brain regions in treated animals. Melatonin potentiated intrinsic antioxidant status, inhibited acid mediated rise in intracellular calcium levels, decreased apoptotic cell death and also markedly inhibited protein kinase C (PKC) influenced AQP4 expression in the cerebral cortex and dorsal striatum.

Significance

Melatonin confers neuroprotection by protein kinase C mediated AQP4 inhibition in ischemic stroke.     

Association between complement factor H Val62Ile polymorphism and age-related macular degeneration susceptibility: A meta-analysis

Background

An increasing body of studies has assessed the contribution of Val62Ile polymorphism to age-related macular degeneration (AMD) risk, but the exact association still remains uncertain. This meta-analysis was undertaken in order to further characterize the potential association between Val62Ile polymorphism and AMD risk in four different ethnic populations.

Methods

A meta-analysis was performed using data available from 16 case–control studies evaluating correlation between the Val62Ile polymorphism and AMD in Caucasian, Chinese, Japanese and South Korean populations. Data extraction and study quality assessment were performed in duplicate. Summary odds ratios (ORs) and 95% confidence intervals (CIs) of allele contrast and genotype contrast were estimated using the random-effects model. The Q-statistic test was used to identify heterogeneity, and the funnel plot was adopted to evaluate publication bias.

Results

Sixteen studies involving a total of 11,400 subjects based on the search criteria were included in the meta-analysis. In overall populations, the Val62Ile polymorphism seemed to be associated with AMD (OR_{AA vs. GG} = 0.40, 95% CI = 0.28–0.59; OR_{AA + GA vs. GG} = 0.72, 95% CI = 0.64–0.80; OR_{AA vs. GC + GG} = 0.50, 95% CI = 0.36–0.70; OR_{A vs. G} = 0.68, 95% CI = 0.58–0.78; OR_{GA vs. GG} = 0.71, 95% CI = 0.65–0.77). Similarly, subgroup analysis also revealed that this polymorphism was related to AMD in all ethnicities.

Conclusions

This meta-analysis suggested that Val62Ile polymorphism was associated with susceptibility to AMD.     

Genetic variants in epoxide hydrolases modify the risk of oligozoospermia and asthenospermia in Han-Chinese population

Objectives

Epoxide hydrolases are involved in detoxifying and excreting the environmental chemicals, which are associated with decreased semen quality and male infertility. We hypothesized that polymorphisms in epoxide hydrolases may be associated with risk of oligozoospermia and asthenospermia.

Design and methods

In this study, 468 fertile controls and 672 idiopathic male infertile patients were recruited. SNPstream and TaqMan assay were used to genotype four single nucleotide polymorphisms in EPHX1 and EPHX2. The semen analysis was performed by computer-assisted semen analysis system.

Results

Our results demonstrated that rs1042064 of EPHX2 was significantly associated with decreased risk of oligozoospermia (OR = 0.65, 95% CI: 0.44–0.98) and asthenospermia (OR = 0.66, 95% CI: 0.46–0.94).

Conclusions

Our results provided evidence that genetic variants in epoxide hydrolases may modify the risk of oligozoospermia and asthenospermia in Han-Chinese population.     

Role of EGFR SNPs in survival of advanced lung adenocarcinoma patients treated with Gefitinib

Aim

As a novel molecularly targeting agent for non-small-cell lung cancer (NSCLC), Gefitinib can block its tyrosine kinase activity of the epidermal growth factor receptor (EGFR). Genetic variations in EGFR may affect its protein function or expression and lead to diverse outcomes in NSCLC patients after Gefitinib therapy. Therefore, this prospective study examined whether EGFR single nucleotide polymorphisms (SNPs) are associated with different survival time in advanced lung adenocarcinoma patients treated with Gefitinib.

Methods

One hundred and twenty-eight patients with stage IIIB or IV lung adenocarcinoma receiving Gefitinib target therapy between 2008 and 2010 were recruited in this study. Six EGFR haplotype-tagging SNPs were genotyped by the Sequenom MassArray system. Survival by different genotypes was compared using Kaplan–Meier methods. Cox proportional hazards models were applied to estimate the effect of prognostic factors on overall survival (OS) and progression-free survival (PFS).

Results

After the median 16.6 months of follow-up, the unfavorable EGFR rs2293347AA or GA genotype was significantly correlated with shorter OS (AA vs. GG: 2.0 vs. 21.0 months; hazard ratio (HR) = 2.44, 95% confidence interval (CI) = 1.06–5.56; P = 0.036; GA vs. GG: 15.0 vs. 21.0 months; HR = 1.75, 95%CI = 1.08–2.86, P = 0.025) compared with the favorable rs2293347GG genotype. The prognostic significance of EGFR rs4947492 polymorphism on OS also existed (GG carriers vs. AA carriers: median OS = 24.6 vs. 14.9 months, HR = 0.29, 95%CI = 0.10–0.83, P = 0.021). No significant associations were found among other EGFR SNPs and survival.

Conclusion

EGFR rs2293347 and rs4947492 SNPs might be potential predictive markers of OS in advanced lung adenocarcinoma patients treated with Gefitinib.     

Association between the ghrelin Leu72Met polymorphism and type 2 diabetes risk: A meta-analysis

Aims

Data on the association between the ghrelin Leu72Met polymorphism and type 2 diabetes are conflicting. A meta-analysis was performed on this topic.

Methods

We searched for case–control studies using electronic databases (Medline and PubMed) and reference lists of studies. Odds ratios (OR) and 95% confidence intervals (CI) assuming dominant, recessive and homozygote comparison genetic models were calculated.

Results

Six case–control studies involving a total of 3417 cases and 3081 controls were included in this meta-analysis. No association was found between the ghrelin Leu72Met polymorphism and type 2 diabetes risk in the overall population in dominant, recessive and homozygote comparison models. However, in subgroup analyses stratified by ethnicity, we found that the risk for type 2 diabetes was decreased in subjects with Met72 + genotypes in Caucasians (OR = 0.79, 95% CI: 0.64–0.98, P_z = 0.030).

Conclusion

The ghrelin Leu72Met polymorphism was protective against type 2 diabetes in Caucasians. Future studies performed in larger sample size are needed to allow a more definitive conclusion.     

Effects of varying tissue sizes on the efficiency of baboon ovarian tissue vitrification

Objective

The aim of this study was to detect the effects of varying tissue sizes on the efficiency of baboon ovarian tissue vitrification.

Study design

The percentages of morphologically normal primordial follicles and the follicles expressing bax protein in ovarian tissues after vitrification–warming were measured. Besides, the 17-β estradiol levels in the culture supernatants were measured.

Results

The percentages of morphologically normal primordial follicles in vitrified–warmed ovarian tissues slicing in 0.5–1.5 mm in length and wide, and 1.0 mm in thickness were significantly higher than those slicing in 2.0 mm in length and wide, and 1.0 mm in thickness. Moreover, the follicles expressing bax protein in vitrified–warmed ovarian tissues slicing in 0.5–1.5 mm in length and wide, and 1.0 mm in thickness were significantly lower than those slicing in 2.0 mm in length and wide, and 1.0 mm in thickness. The 17-β estradiol levels in the culture supernatants slicing in 1.0–1.5 mm in length and wide, and 1.0 mm in thickness were significantly higher than those slicing in 0.5 mm or 2.0 mm in length and wide, and 1.0 mm in thickness.

Conclusions

Cortex piece slicing in 1.0–1.5 mm in length and wide, and 1.0 mm in thickness is suitable for baboon ovarian vitrification.     

Population-based and family-based studies on the protein tyrosine phosphatase non-receptor 22 gene polymorphism and type 1 diabetes: A meta-analysis

Purpose

Studies investigating the association between PTPN22 gene C1858T polymorphism and type 1 diabetes (T1D) susceptibility among Caucasian population have reported conflicting results. To investigate this inconsistency, we performed a meta-analysis of all available studies dealing with the relationship between the PTPN22 C1858T polymorphism and T1D.

Methods

Databases including PubMed, Web of Science, and EMBASE were searched to find relevant studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of association.

Results

In total, 33 population-based studies with 22, 485 cases and 35, 292 controls, 9 family-based studies involving 7276 families were included. Under the random-effects model, the per-allele overall OR of the C1858T polymorphism for T1D was 1.89 (95% CI: 1.76–2.02, P < 10^− 5) by pooling all available case–control studies. In addition, we found significant evidence for overtransmission of the risk T allele in family-based studies (overall OR _TDT = 1.58, 95% CI: 1.43–1.74; P < 10^− 5). The summary OR from case–control and family-based association studies was 1.81 (95% CI: 1.70–1.93, P < 10^− 5).

Conclusions

In conclusion, this meta-analysis suggests that C1858T polymorphism in PTPN22 is associated with elevated T1D risk among Caucasian population.     

Selective cytotoxicity of intense nanosecond-duration electric pulses in mammalian cells

Background

Nanosecond electric pulses (EP) disrupt cell membrane and organelles and cause cell death in a manner different from the conventional irreversible electroporation. We explored the cytotoxic effect of 10-ns EP (quantitation, mechanisms, efficiency, and specificity) in comparison with 300-ns, 1.8- and 9-μs EP.

Methods

Effects in Jurkat and U937 cells were characterized by survival assays, DNA electrophoresis and flow cytometry.

Results

10-ns EP caused apoptotic or necrotic death within 2–20 h. Survival (S, %) followed the absorbed dose (D, J/g) as: S = αD^(−K), where coefficients K and α determined the slope and the “shoulder” of the survival curve. K was similar in all groups, whereas α was cell type- and pulse duration-dependent. Long pulses caused immediate propidium uptake and phosphatidylserine (PS) externalization, whereas 10-ns pulses caused PS externalization only.

Conclusions

1.8- and 9-μs EP cause cell death efficiently and indiscriminately (LD₅₀ 1–3 J/g in both cell lines); 10-ns EP are less efficient, but very selective (LD₅₀ 50–80 J/g for Jurkat and 400–500 J/g for U937); 300-ns EP show intermediate effects. Shorter EP open propidium-impermeable, small membrane pores (”nanopores”), triggering different cell death mechanisms.

General significance

Nanosecond EP can selectively target certain cells in medical applications like tumor ablation.