DNA topoisomerase II is required for condensation and separation of mitotic chromosomes in S. pombe

We show that DNA topoisomerase II (topo II) is continuously required for mitotic chromosome changes in Schizosaccharomyces pombe. We constructed cold-sensitive (cs) or temperature-sensitive (ts) strains mutated in the genes coding for topo II (top2) and beta-tubulin (nda3). The ATP-dependent activity of the top2cs gene product is cs in vitro. The cloned top2cs gene sequence predicts an amino acid substitution. A cs top2-cs nda3 double mutant at 20 degrees C shows long, entangled chromosomes, which condense and separate upon the shift to permissive temperatures. If spindle formation is prevented at permissive temperatures, the chromosomes condense but do not separate. Thus topo II is required for final chromosome condensation; moreover, pulse-shift experiments show that topo II is required for chromatid disjuction. Experiments with ts top2-cs nda3 cells show that topo II is also required for chromosome separation in anaphase: inactivation of topo II and activation of beta-tubulin allow normal spindle formation but result in "streaked" chromosomes.

Carcinogenicity in mice of mutagenic compounds from a tryptophan pyrolyzate

The compounds 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole and 3-amino-1-methyl-5H-pyrido[4,3-b]indole, which are potent mutagens in a tryptophan pyrolyzate, ar hepatic carcinogens when given orally to mice at concentrations of 200 parts per million in a pellet diet. Female mice showed higher susceptibilities to both compounds than male mice.

A naturally occurring functional allele of the rice waxy locus has a GT to TT mutation at the 5' splice site of the first intron

In cultivated rice two wild-type alleles, Wxa and Wxb, predominate at the waxy locus, which encodes granule-bound starch synthase. The activity of Wxa is 10-fold higher than that of Wxb at the level of both protein and mRNA. Wxb has a +1G to T mutation at the 5' splice site of the first intron. Sequence analysis of Wxb transcripts revealed that splicing occurs at the mutant AG/UU site and at two cryptic sites: the first is A/GUU, one base upstream of the original site and the second is AG/GU found approximately 100 bases upstream of the mutant splice site. We introduced single base mutations to the 5' splice sites of both Wxa and Wxb, fused with the gus reporter gene and introduced them into rice protoplasts. Analysis of GUS activities and transcripts indicated that a G to T mutation in Wxa reduced GUS activity and the level of spliced RNA. Conversely, a T to G mutation of Wxb restored GUS activity and the level of spliced RNA to that of wild-type Wxa. These results demonstrated that the low level expression of Wxb results from a single base mutation at the 5' splice site of the first intron. It is of interest that the Wxb allele of rice carrying the G to T mutation of intron 1 has been conserved in the history of rice cultivation because there is a low amylose content of the seed caused by this mutation.

Carcinogenicity in mice of a mutagenic compound, 2-amino-3-methylimidazo[4,5-f]quinoline, from broiled sardine, cooked beef and beef extract

A potent mutagenic compound, 2-amino-3-methylimidazo-[4,5-f]quinoline (IQ), isolated from broiled sardines, cooked beef and beef extract was tested for carcinogenicity in CDF1 mice of both sexes. Mice were given diet containing 0.03% IQ or control diet for up to 675 days. Tumors were observed mainly in the liver, forestomach and lung. In the mice given IQ, the incidences of these tumors were as follows: liver tumors - 41% in males and 75% in females; tumors of the forestomach - 41% in males and 31% in females; lung tumors - 69% in males and 42% in females. In the control mice, incidences of these tumors were as follows: liver tumors - 9% in males and 8% in females; tumors of the forestomach - 3% in males and 0% in females; lung tumors - 21% in males and 18% in females. The incidences of tumors in the liver, forestomach and lung were significantly higher in mice given IQ than in control mice.

Carcinogenicity in rats of the mutagenic compounds 1-nitropyrene and 3-nitrofluoranthene

1-Nitropyrene and 3-nitrofluoranthene are present in diesel exhaust, in pollutants in air, and were also present in certain xerographic toners and copies. Their carcinogenicities were studied in male F344/DuCrj rats by subcutaneous injection. Sarcomas, mainly malignant fibrous histiocytomas at the site of injection were induced in 8 to 17 (47%) rats by 1-nitropyrene and in 4 of 10 (40%) rats by 3-nitrofluoranthene. Some tumors were serially transplantable in the same strain of rats.

Protein-tyrosine phosphatase-1B negatively regulates insulin signaling in l6 myocytes and Fao hepatoma cells

Insulin signaling is regulated by tyrosine phosphorylation of the signaling molecules, such as the insulin receptor and insulin receptor substrates (IRSs). Therefore, the balance between protein-tyrosine kinases and protein-tyrosine phosphatase activities is thought to be important in the modulation of insulin signaling in insulin-resistant states. We thus employed the adenovirus-mediated gene transfer technique, and we analyzed the effect of overexpression of a wild-type protein-tyrosine phosphatase-1B (PTP1B) on insulin signaling in both L6 myocytes and Fao cells. In both cells, PTP1B overexpression blocked insulin-stimulated tyrosine phosphorylation of the insulin receptor and IRS-1 by more than 70% and resulted in a significant inhibition of the association between IRS-1 and the p85 subunit of phosphatidylinositol 3-kinase and Akt phosphorylation as well as mitogen-activated protein kinase phosphorylation. Moreover, insulin-stimulated glycogen synthesis was also inhibited by PTP1B overexpression in both cells. These effects were specific for insulin signaling, because platelet-derived growth factor (PDGF)-stimulated PDGF receptor tyrosine phosphorylation and Akt phosphorylation were not inhibited by PTP1B overexpression. The present findings demonstrate that PTP1B negatively regulates insulin signaling in L6 and Fao cells, suggesting that PTP1B plays an important role in insulin resistance in muscle and liver.

Carcinogenicity test of quercetin and rutin in golden hamsters by oral administration

Quercetin and its glycoside, rutin were tested for carcinogenicity in non-inbred golden hamsters of both sexes. In Experiment I, 10% quercetin, 10% rutin, or control diet was given to animals for 735 days. In this experiment, tumors appeared mainly in the forestomach, but the incidence was not statistically different among the three groups. Quercetin and rutin were not carcinogenic under these conditions. In Experiment II, Group 1 was given 4% quercetin diet for 709 days. Group 2 was given 1% quercetin diet for 351 days and then the basal diet for 350 days. Group 3 was given 1% quercetin diet and then 1% croton oil diet and Group 4 was given the basal diet followed by 1% croton oil diet, for the same periods as Group 2. Group 5 was given the basal diet for 701 days. In Experiment II, papillomas of the forestomach appeared in Groups 1, 2, and 5, and papillomatosis in Group 3 and 4. There were no statistical differences among experimental groups and respective controls. Thus, quercetin was not carcinogenic when given at the concentrations of 4% and 1%; even with the administration of 1% croton oil after 1% quercetin, there was no increase in tumor incidence.

Chronic hepatitis E: a review of the literature

In 1978, the first case of hepatitis E was identified as non-A, non-B hepatitis. Hepatitis E virus (HEV) infection is believed to be one of the common causes of enterically transmitted acute hepatitis in developing countries and is rare in developed countries, except in patients with a history of travel. However, an increasing number of chronic HEV infection cases have recently been reported in developed countries. In these countries, immunosuppressed patients with HEV infection, such as organ transplant recipients, human immunodeficiency virus (HIV)-infected patients or patients with haematological malignancies, could develop chronic hepatitis E (CHE) infection. Approximately 60% of HEV infections in immunocompromised patients after solid organ transplantation evolve to CHE without antiviral treatment. Clinical manifestations of CHE are often nonspecific symptoms. Many patients with CHE infection are asymptomatic, but some have jaundice, fatigue, abdominal pain, fever and asthenia. Several extrahepatic manifestations have also been reported. Although chronic HEV infection can result in progressive severe liver failure and cirrhosis, diagnosis is often controversial because of the lack of specific diagnostic criteria. Many CHE cases are diagnosed by HEV RNA-positive serum or stool for >6 months. Immunosuppressive drugs, interferon-alpha and ribavirin have been used for treatment. Diagnostic reverse-transcription polymerase chain reaction is useful for estimating treatment efficacy. Preventive measures for HEV infection have been discussed, while systematic guidelines have not yet been reported.

Cloning and sequencing of Schizosaccharomyces pombe DNA topoisomerase I gene, and effect of gene disruption

We cloned the structural gene topl+ for Schizosaccharomyces pombe DNA topoisomerase I (topo I) by hybridization. An eight-fold increase of topo I relaxing activity was obtained in S. pombe cells transformed with multicopy plasmid with topl+ insert. Nucleotide sequence determination showed a hypothetical coding frame interrupted by two short introns, encoding a 812 residue polypeptide (M.W. 94,000), 43 residues longer than and 47% homologous to Saccharomyces cerevisiae topo I. We show that the topl (null) strain made by gene disruption is viable, although its generation time is 20% longer than that of wild type. The topl locus is mapped in the long arm of chromosome II, using the Leu+ marker integrated with the cloned topl+ sequence. We constructed a double mutant topl (null) top2 (ts) and found its defective phenotype similar to that of previously obtained topl (heat sensitive) top2 (ts). The other double mutant topl (null) top2 (cs), however, was lethal. Our results suggest that topl+ gene of S. pombe is dispensable only if topo II activity is abundant.

Carcinogenicity in mice of mutagenic compounds from glutamic acid and soybean globulin pyrolysates

2-Amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole and 2- aminodipyrido [1,2-a:3',2'-d]imidazole, potent mutagens from glutamic acid pyrolysate, were given orally to CDF1 mice of both sexes at concentrations of 0.05% in pellet diet. 2-Amino-3-methyl-9H-pyrido[2,3-b]indole and 2-amino-9H-pyrido[2,3-b]indole, potent mutagens from soybean globulin pyrolysate, were given to CDF1 mice of both sexes at concentrations of 0.08%. Hepatocellular carcinomas and hemangioendothelial sarcomas in the brown adipose tissue were induced in high incidence by all these compounds.

Determination of hydrogen sulfide and acid-labile sulfur in animal tissues by gas chromatography and ion chromatography

A sensitive and reliable method was developed for the determination of hydrogen sulfide and acid-labile sulfur (ALS) in animal tissues using gas chromatography with flame photometric detector (GC-FPD) and ion chromatography (IC). Hydrogen sulfide trapped in alkaline solution was determined by GC-FPD as hydrogen sulfide or by IC as sulfate after oxidation with hydrogen peroxide. Sodium sulfide used as a source of hydrogen sulfide was standardized by IC. Fresh rat liver and heart tissues contained 112.2+/-23.0 and 274.1+/-34.6 nmol/g of ALS respectively. Free hydrogen sulfide was not detected.

Antibody fusions with fluorescent proteins: a versatile reagent for profiling protein expression

We developed a system by which antibodies, fused to fluorescent proteins with different wavelengths, can be prepared within a month against various antigens. An antibody library composed of a large number of single-chain Fv-CL fragment was constructed by means of a phage-display system. The constructs were designed to facilitate changing of the protein forms by simple enzyme manipulation. In the present study, we adopted a molecular form of antibody in which a single-chain Fv-CL fragment is fused with a green fluorescent protein (GFP) or red fluorescent protein (RFP). In addition, a His-tag was inserted between CL and GFP (or RFP). We describe the utility of this system using Caenorhabditis elegans embryo as a model.

Expression of a dominant negative SHP-2 in transgenic mice induces insulin resistance

To elucidate the roles of SHP-2, we generated transgenic (Tg) mice expressing a dominant negative mutant lacking protein tyrosine phosphatase domain (DeltaPTP). On examining two lines of Tg mice identified by Southern blot, the transgene product was expressed in skeletal muscle, liver, and adipose tissues, and insulin-induced association of insulin receptor substrate 1 with endogenous SHP-2 was inhibited, confirming that DeltaPTP has a dominant negative property. The intraperitoneal glucose loading test demonstrated an increase in blood glucose levels in Tg mice. Plasma insulin levels in Tg mice after 4 h fasting were 3 times greater with comparable blood glucose levels. To estimate insulin sensitivity by a constant glucose, insulin, and somatostatin infusion, steady state blood glucose levels were higher, suggesting the presence of insulin resistance. Furthermore, we observed the impairment of insulin-stimulated glucose uptake in muscle and adipocytes in the presence of physiological concentrations of insulin. Moreover, tyrosine phosphorylation of insulin receptor substrate-1 and stimulation of phosphatidylinositol 3-kinase and Akt kinase activities by insulin were attenuated in muscle and liver. These results indicate that the inhibition of endogenous SHP-2 function by the overexpression of a dominant negative mutant may lead to impaired insulin sensitivity of glucose metabolism, and thus SHP-2 may function to modulate insulin signaling in target tissues.

Silencing of an aleurone-specific gene in transgenic rice is caused by a rearranged transgene

In rice, silencing of the aleurone-specific Ltp2-gus transgene, causing easily detectable staining patterns on the grain surface, offers a convenient tool to study quantitative aspects of gene silencing in monocots. In this paper we analyzed phenotypes, occurrence, inheritance and environmental effects on the silencing. We also report on the cloning of transgenes, determination of their structure and analysis of transcripts from the transgene loci. The results show that various patterns of silencing appeared in the R2 generation at which most of the transgenes became homozygous and that they were inherited for five generations. In addition, silencing independently occurred in three generations and reversion to full expression was also found. Cloning of transgenes from a silenced L3.3 line demonstrated that this line carried two transgene loci: one carried an intact Ltp2-gus gene and the other carried a rearranged transgene in which part of the gus gene was in the antisense orientation. Analysis of gus transcripts indicated that partial antisense RNA derived from the rearranged transgene was present in silenced lines and was polyadenylated but that it was absent in non-silenced lines. RNA analyses suggested that the Ltp2-gus silencing in the aleurone layer was post-transcriptional and that it may be caused by interaction of partial antisense gus transcripts with normal sense transcripts. Possible involvement of antisense transcripts in post-transcriptional silencing is discussed.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Molecular cloning of a human protein that binds to the retinoblastoma protein and chromosomal mapping

We have isolated distinct clones for cellular proteins that bind to the retinoblastoma protein by direct screening of cDNA expression libraries using purified pRB as a probe. The total nucleotide sequence of one of these clones, RBQ-3, was determined and found to encode a protein of 66 kDa localized in the nucleus. The RBQ-3 preferentially binds to underphosphorylated pRB. The region used for binding to this protein was mapped to the E1A-binding pocket B of pRB, which has sequence similarity to the general transcription factor TFIIB. We have mapped the gene to 1q32 using polymerase chain reaction analysis on a human-hamster hybrid cell panel and chromosomal fluorescence in situ hybridization.

Rapid growth of a pseudosarcoma of the esophagus

The growth of a pseudosarcoma of the esophagus was observed chronologically by serial esophagography. Esophagograms taken 12 and 6 months prior to diagnosis showed no abnormalities. At diagnosis, the tumor in the lower esophagus had a polypoid and nodular surface with a stalk, and it was approximately 3 cm in diameter. Four months later, the tumor had increased in size to 4 cm in diameter. The tumor was 5 cm in length and incarcerated into the stomach with an elongated stalk at operation. The growth curve was linear on semilogarithmic paper; its doubling time was calculated as 2.2 months. The surgical specimen showed squamous cell carcinoma and spindle cell sarcoma-like elements that comprised the greater part of the tumor. The sarcoma-like elements had metastasized to the abdominal lymph nodes. These findings confirm that this polypoid tumor grows rapidly.

A new antidiabetic agent (JTT-501) rapidly stimulates glucose disposal rates by enhancing insulin signal transduction in skeletal muscle

A newly synthesized antidiabetic agent, JTT-501 is an isoxazolidinedione rather than a thiazolidinedione. An oral dose of JTT-501 (100 mg x kg(-1) x day(-1)) given to 12-week-old male Zucker fatty rats for 7 days led to the amelioration of both hyperinsulinaemia (40% of non-treated) and hypertriglyceridaemia (23% of non-treated) as well as a 2.4-fold increased insulin sensitivity as determined by a euglycaemic insulin clamp. In our study, we further evaluated the acute effect of JTT-501 on both the glucose infusion rates (GIR) and insulin signalling in skeletal muscle. Male Sprague-Dawley (SD) rats aged 10 weeks were injected intravenously with JTT-501 (5 mg/kg) and then a euglycaemic insulin clamp was initiated and glucose infusion rates monitored for 150 min. We found that this treatment increased the glucose infusion rate by 33% during the last 30 min in SD rats. After the clamp had been initiated for 30 min, the insulin-stimulated phosphatidylinositol 3-kinase (PI3-kinase) activities co-immunoprecipitated with insulin receptor substrate 1 (IRS-1) were also enhanced, resulting in increased glycogen synthase activities in the soleus muscles. Treatment with JTT-501 also enhanced the phosphorylation of insulin receptors and insulin receptor-substrate 1 rapidly as well as the phosphatidylinositol 3-kinase activities, which were stimulated by a bolus injection of insulin. Similarly, JTT-501 stimulated the glucose infusion rate by 30% and enhanced insulin signalling in Zucker fatty rats. In conclusion, a newly developed isoxazolidinedione, JTT-501, rapidly potentiates the insulin sensitivity of skeletal muscle by enhancing insulin signalling and could be useful for the treatment of insulin-resistant diabetic subjects.

Liver cancer and precancerous changes in rats induced by the basic fraction of tryptophan pyrolysate

The basic fraction of a tryptophan pyrolysate (Trp-P-BF) was given orally to Wistar rats for about 2 years. In Experiment I, 5 male rats each were given 0.2, 0.4, 0.6 and 0.8% Trp-P-BF. Dose-dependent growth retardation was observed in these groups and neoplastic nodules were found in the liver of 1 rat given 0.2% Trp-P-BF and a hepatocellular carcinoma was found in 1 rat given 0.4% Trp-P-BF diet. In Experiment II, 25 rats of both sexes were fed 0.5% or 0.2% Trp-P-BF diet. Neoplastic nodules were induced in 2 of 22 males and 5 of 18 females given 0.2% Trp-P-BF diet. Mammary adenomas developed, but no neoplastic nodules were found in the liver of rats fed on 0.05% Trp-P-BF or control diet. Females were more sensitive to Trp-P-BF than males.

Genome-Wide Association Study of Age-Related Macular Degeneration Reveals 2 New Loci Implying Shared Genetic Components with Central Serous Chorioretinopathy

PURPOSE

To investigate the genetic architecture of age-related macular degeneration (AMD) in a Japanese population.

DESIGN

Genome-wide association study (GWAS).

PARTICIPANTS

Three thousand seven hundred seventy-two patients with AMD and 16 770 control participants from the Japanese population were enrolled in the association analyses.

METHODS

We conducted a meta-analysis of 2 independent GWASs that included a total of 2663 patients with AMD and 9471 control participants using the imputation reference panel for genotype imputation specified for the Japanese population (n = 3541). A replication study was performed using an independent set of 1109 patients with AMD and 7299 control participants.

MAIN OUTCOME MEASURES

Associations of genetic variants with AMD.

RESULTS

A meta-analysis of the 2 GWASs identified 6 loci significantly associated with AMD (P < 5.0 × 10^-8). Of these loci, 4 were known to be associated with AMD (CFH, C2/FB, TNFRSF10A, and ARMS2), and 2 were novel (rs4147157 near WBP1L and rs76228488 near GATA5). The newly identified associations were confirmed in a replication study (P < 0.01). After the meta-analysis of all datasets, we observed strong associations in these loci (P = 1.88 × 10^-12 and P = 1.35 × 10^-9 for meta-analysis for rs4147157 and rs76228488, respectively). When we looked up the associations in the reported central serous chorioretinopathy (CSC) GWAS conducted in the Japanese population, both loci were associated significantly with CSC (P = 4.86 × 10^-3 and P = 4.28 × 10^-3 for rs4147157 and rs76228488, respectively). We performed a genetic colocalization analysis for these loci and estimated that the posterior probabilities of shared causal variants between AMD and CSC were 0.39 and 0.60 for WBP1L and GATA5, respectively. Genetic correlation analysis focusing on the epidemiologically suggested clinical risk factors implicated shared polygenic architecture between AMD and smoking cessation (r_g [the measure of genetic correlation] = -0.33; P = 0.01; false discovery rate, 0.099).

CONCLUSIONS

Our findings imply shared genetic components conferring the risk of both AMD and CSC.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Disproportion of lamellar capillary non-perfusion in proliferative diabetic retinopathy on optical coherence tomography angiography

PURPOSE

To characterise the non-perfused areas (NPAs) in the superficial and deep capillary layers (sNPAs and dNPAs, respectively) in the posterior pole in proliferative diabetic retinopathy (PDR) on wide-field optical coherence tomography angiography (OCTA) images.

METHODS

We retrospectively reviewed 104 eyes of 70 patients with PDR from whom wide-field swept source OCTA images were acquired. sNPAs and dNPAs were manually measured in each quadrant of the inner (1-3 mm diameter), intermediate (3-6 mm), and outer (6-10 mm) rings centred on the fovea. Two qualitative findings, that is, segmented NPAs and periarteriolar NPAs, were also compared.

RESULTS

The dNPAs were greater than the sNPAs (p<0.001) in each subfield. The outer ring had higher rates of deep NPAs than did the intermediate ring in the superior, inferior and temporal quadrants (p=0.010, p=0.004 and p<0.001, respectively), whereas no differences were detected in the nasal quadrant (p=1.000). Similarly, sNPA rates were higher in the outer ring than in the intermediate ring in the inferior and temporal subfields (p=0.003 and p<0.001, respectively). In 45 eyes with extensive NPAs, there were modest correlations between the dNPAs in the nasal and temporal quadrants in the intermediate (ρ=0.341, p=0.026) and outer (ρ=0324, p=0.032) rings, whereas sNPAs exhibited no associations. Segmented NPAs were delineated more frequently in the superficial layer than in the deep layer (p<0.001). Periarteriolar NPAs were more frequent in the deep layer (p<0.001).

CONCLUSIONS

Three-dimensional assessment of wide-field OCTA promotes a better understanding of the enigmatic disproportion of lamellar NPAs in the posterior pole in PDR.

Insulin-induced c-Jun N-terminal kinase activation is negatively regulated by protein kinase C delta

We investigated the role of protein kinase C (PKC) in insulin-induced c-Jun N-terminal kinase (JNK) activation in rat 1 fibroblasts expressing human insulin receptors. Insulin treatment led to increased SAPK/ERK kinase 1 (SEK1) phosphorylation, and then stimulated JNK activity in a dose- and time-dependent manner, as measured either by a solid-phase kinase assay using glutathione S-transferase (GST)-c-Jun fusion protein as a substrate, or by quantitation of the levels of phosphorylated JNK by Western blotting using anti-phospho-JNK antibody. Insulin-induced JNK activation was potentiated by either preincubating cells with 2 nM GF109203X (PKC inhibitor) or down-regulation of PKC by overnight treatment with 100 nM tetradecanoyl phorbol acetate. In contrast, brief preincubation with 100 nM tetradecanoyl phorbol acetate inhibited the insulin- induced JNK activation. Furthermore, we found that 5 microM rottlerin, a PKCdelta inhibitor, enhanced insulin-induced JNK activation, but a PKCbeta inhibitor, LY333531, had no effect. Consistent with these findings, overexpression of PKCdelta led to decreased insulin-induced JNK activation, whereas overexpression of PKCbeta had no effect. Although overexpression of wild-type PKCdelta attenuated insulin-induced JNK activation, a kinase-dead PKCdelta mutant did not cause such attenuation. Finally, we found that the magnitude of insulin-induced JNK activation was inversely correlated with the expression level of PKCdelta among different cell lines. In conclusion, the expression of PKCdelta may negatively regulate insulin-induced JNK activation.

Tumor promoting activity of teleocidin in skin and forestomach of mice initiated transplacentally with 7,12-dimethylbenz(a)anthracene

Experiments on the effect of transplacental initiation with 7,12-dimethylbenz(a)anthracene (DMBA) and postnatal promotion with teleocidin were carried out in mice. The percentage of tumor-bearing mice among females treated with DMBA transplacentally on day 17 of gestation and postnatally by topical application of teleocidin to the skin of the back was 73.3% in week 30, whereas that among females treated with DMBA on day 10 of gestation and postnatally by topical application of teleocidin was 20.0%. This indicates that teleocidin shows potent tumor promoting activity on mouse skin in a transplacental initiation and postnatal promotion protocol. Furthermore, in the males treated with DMBA transplacentally on day 17 of gestation and given diet containing 0.01% teleocidin postnatally five tumors of the forestomach were found in 5 of 19 effective mice (26.3%) in week 52. One of these five tumors was a squamous cell carcinoma, and the others were papillomas. This indicates that teleocidin also has tumor promoting activity in the forestomach of mice.