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In a prospective study, SARS-CoV-2 IgG seroprevalence was assessed during the second pandemic wave (W2) in a cohort of Inflammatory Bowel Disease (IBD) patients using biologics. The secondary aim was to compare, in the same cohort, the frequency of seropositivity and of COVID-19 during the second vs. the first (W1) wave.From November 2020 to March 2021, SARS-CoV-2 IgG seropositivity and the prevalence of COVID-19 were assessed in a cohort of IBD patients using biologics already studied at W1.age ≥ 18 years; diagnosis of IBD; follow-up; written consent.SARS-CoV-2 vaccination. Risk factors for infection, compatible symptoms, history of infection or COVID-19, nasopharyngeal swab test were recorded. Data were expressed as median [range]. The χ2 test, Student's t-test, logistic regression analysis was used.IBD cohort at W1 and W2 included 85 patients: 45 CD (52.9%), 40 UC (47.1%). When comparing the same 85 patients at W2 vs. W1, a higher SARS-CoV-2 seroprevalence at W2 was at the limit of the statistical significance (9.4% vs. 2.3%; p=0.05). The prevalence of COVID-19 at W2 vs. W1 was 3.5% (3/85) vs. 0% (0/85) (p=0.08). Contacts with COVID-19 patients and symptoms compatible with COVID-19 were more frequent at W2 vs. W1 (18.8 % vs. 0%; p=0.0001; 34.1% vs. 15.3%; p=0.004). At W2, history of contacts and new onset diarrhea were more frequent in seropositive patients [4/8 (50%) vs. 12/77 (15.6%); p=0.01 and 4/8 (50%) vs. 2/77 (2.6%); p=0.0001]. At W2, the risk factors for seropositivity included cough, fever, new onset diarrhea, rhinitis, arthromyalgia, dysgeusia/anosmia at univariate (p0.05), but not at multivariate analysis. History of contacts was the only risk factor for seropositivity at univariate (p=0.03), but not at multivariate analysis (p=0.1).During W2, characterized by a high viral spread, IBD and biologics appeared not to increase the prevalence of SARS-CoV-2 infection or COVID-19 disease. New onset diarrhea mimicking IBD relapse may be observed in patients with SARS-CoV-2 infection.

Al Khiday, located on the bank of the White Nile in Sudan, offers an exceptionally preserved stratigraphic sequence, providing a unique opportunity to use organic residue analysis to investigate diet and subsistence over the full course of the Khartoum Mesolithic together with possible continuity or change into the Early Neolithic, a period of nearly 3500 years (7000-4500 cal BC). Whilst the vast and diverse Mesolithic fish assemblage indicates a strong reliance on products from aquatic habitats, floodplains, vegetated marshes and open water, results from the lipid residue analysis suggest that the fish were not cooked in the pots, likely being consumed in other ways. Rather, pots were more specialised in processing plants, wild grasses, leafy plants and sedges, confirmed by experimental analysis, and for the first time, providing direct chemical evidence for plant exploitation in the Khartoum Mesolithic. Non-ruminant fauna, such as warthog and low lipid-yielding reptiles such as Adanson’s mud turtle and Nile monitor lizard, which were found in significant numbers at al-Khiday, were likely also cooked in pots. There is little evidence for the processing of wild ruminants in the Mesolithic pots, suggesting either that ruminant species were not routinely hunted, or, that large wild fauna may have been cooked in different ways, possibly grilled over fires. These data suggest sophisticated economic strategies by sedentary people likely exploiting their ecological niche to the fullest. Pottery use changes considerably in the Early Neolithic, with ruminant products being more routinely processed in pots, and while the exploitation of domesticates cannot be confirmed by a small faunal assemblage, some dairying does take place. In summary, our results provide valuable information on Early and Middle Holocene lifeways in central Sudan.

Background Colorectal cancer (CRC) risk is increased in patients (pts) with long-standing colitis related to Inflammatory Bowel Disease (IBD). A higher frequency mucinous and signet-ring colonic adenocarcinoma has been suggested in IBD, but data regarding risk factors for these aggressive CRC are currently lacking. Primary aim was to assess the frequency of mucinous and signet-ring adenocarcinoma in IBD pts with CRC. Secondary aim was to assess risk factors for these histotypes of CRC. Methods From January 2002 to July 2022, all IBD pts with concomitant CRC were retrospectively enrolled. Inclusion criteria: 1) age ≥18; 2) well-defined diagnosis of IBD and CRC; 3) available histological and surgical report. Exclusion criteria: Missing data. Characteristics of IBD were reported according to standard criteria. Data were expressed as median [range]. Student-t Test and χ2 test were used for comparisons. Univariate logistic regression model was applied for assessing risk factors for mucinous and signet-ring adenocarcinoma (OR [95%CI]). Results The study population included 40 IBD pts with concomitant CRC: 24 (60%) with Ulcerative Colitis (UC) and 16 (40%) with Crohn’s Disease (CD). CRC included standard adenocarcinoma in 23 (57.5%) and mucinous or signet-ring in 17 (42.5%) pts. CD was more frequently stricturing in pts with standard adenocarcinoma (7 [77.8%] vs 1 [14.4%], p=0.04). CRC most frequently involved the rectum in pts with mucinous or signet-ring adenocarcinoma vs standard adenocarcinoma (4 [17.4%] vs 8 [47.1%]; p=0.04). Other IBD characteristics did not differ between standard and mucinous or signet-ring adenocarcinoma, including: age at CRC diagnosis (61 [30-80] vs 53 [29.80]; p=0.61), gender (F): 8 [34.8%] vs 5 [29.4%]; p=0.98), IBD duration at CRC diagnosis (14 [1-45] vs 17 [1-36]; p=0.74), smoking status (p=0.78), IBD type (UC: 14 [60.9%] vs 9 [56.3%]; p=0.84), UC extent and CD localization, frequency of perianal disease (p=0.37), thiopurine (p=0.55) or biologic (p=0.55) use. The proportion of pts surgically treated for CRC (20 [86.9%] vs 17 [100%], p=0.34) and the frequency of CRC-related death (3 [13.1%] vs 5 [29.4%]; p=0.37) were also comparable between groups. At diagnosis, CRC stage was comparable between pts with standard vs mucinous or signet-ring adenocarcinoma (stage I: 6 [26.1%] vs 1 [5.9%]; p=0.21; II: 9 [39.1%] vs 4 [23.5%]; p=0.48; III: 5 [21.7%] vs 7 [41.2%]; p=0.34); IV: 3 [13.1%] vs 2 [11.8%]; p=0.71). At univariate analysis, no specific risk factors for mucinous and signet-ring colonic adenocarcinoma were detected. Conclusion In the tested cohort of IBD patients with CRC, mucinous and signet-ring adenocarcinomas were observed in almost half of cases, although no specific risk factors were identified.

Insulin-dependent individuals with diabetes are at risk for a severe hypoglycemic event that may predispose them to several repeat episodes during which the normal counter regulatory mechanisms that protect against hypoglycemia fail to be activated. This state of hypoglycemia unawareness is characterized by a failure of glucagon release, preventing mobilization of endogenous glucose stores from the liver. We describe the discovery of a novel hormone, produced in pancreatic delta cells, which stimulates glucagon production and release, particularly under low glucose conditions. We hypothesize that this hormone, called neuronostatin, may be effective as a co-therapy with insulin to prevent repeated, potentially fatal episodes of recurrent hypoglycemia.

Micro-Raman spectroscopy has been used to monitor structural defects and stress state developing in diamond due to formation of 3D graphitic electrodes for the achievement of optimized carrier collection in ionizing radiation and particle diamond detectors. Buried graphitic pillars were fabricated in a single-crystal CVD-diamond sample by means of a 400 fs pulsed laser operating at λ = 1030 nm. The same conditions were also used for the realization of two series of graphitic strips on the surface allowing buried pillars connections. Micro-Raman spectra of untreated regions exhibit the typical diamond peak at 1332 cm−1 which largely changes within the laser modified regions, where a G band in the range 1580–1600 cm−1 is also detected. Strength decrease, shifting and broadening of the diamond Raman peak are observed by crossing graphitic electrodes and along buried pillars, pointing out that phase transition from diamond to graphitic carbon is accompanied both by stress development and structural disorder in the residual diamond tissue. In these regions, Raman spectra also exhibit a broad photoluminescence background signal, whose intensity appears related to graphitization process. In particular, a splitting of the diamond Raman peak is detected around pillars on the top surfaces suggesting the occurrence of a laser-induced biaxial stress. From these results it is then tentatively suggested that conduction in the realized electrodes occurs through both conductive graphitic phases and disordered diamond paths, whereas detector performance is mainly related to charge transport within virgin diamond.

Neuronostatin (NST) is a recently described peptide that is produced from the somatostatin preprohormone in pancreatic δ-cells. NST has been shown to increase glucagon secretion from primary rat pancreatic islets in low-glucose conditions. Here, we demonstrate that NST increases proglucagon message in α-cells and identify a potential mechanism for NST's cellular activities, including the phosphorylation of PKA following activation of the G protein-coupled receptor, GPR107. GPR107 is abundantly expressed in the pancreas, particularly, in rodent and human α-cells. Compromise of GPR107 in pancreatic α-cells results in failure of NST to increase PKA phosphorylation and proglucagon mRNA levels. We also demonstrate colocalization of GPR107 and NST on both mouse and human pancreatic α-cells. Taken together with our group's observation that NST infusion in conscious rats impairs glucose clearance in response to a glucose challenge and that plasma levels of the peptide are elevated in the fasted compared with the fed or fasted-refed state, these studies support the hypothesis that endogenous NST regulates islet cell function by interacting with GPR107 and initiating signaling in glucagon-producing α-cells.

A detailed characterization under 90Sr β-particles and 4.5 MeV protons micro-beam of a single-crystal CVD diamond-based three-dimensional detector with surface and buried graphite electrodes is presented. Pillar contacts, 300 µm long and 30 µm diameter, were fabricated by using a femtosecond laser operating at 1030 nm wavelength and 400 fs pulse duration. Charge collected under 90Sr β-particles was measured in front and back irradiation conditions, pointing out that the pillars contribute to the charge collection. Charge collection efficiency (CCE) was measured to be up to 94% under proton beam irradiation. Results of a comprehensive study, including crossed-polarizers imaging, numerical simulation of the electric field distribution, and proton mapping, show that CCE is not affected from the stress induced by the pillar fabrication, and that the electric field strength is high enough to partially compensate for carrier recombination in the defected regions surrounding the pillars.

We introduce the electrical characterization of 2.5 mm-long graphite pillars buried in single crystal CVD diamond. A mode-locked Ti:Sapphire laser generating 5 ps pulses at the wavelength of 800 nm with a repetition rate of 1 kHz has been used to directly produce graphite columns with a diameter of about 10 m and an aspect ratio greater than 240. A pair of 12 pillars was realized within the diamond bulk starting from opposite lateral faces resulting in an interdigitated-like structure buried within the diamond volume. Tests with 2.28 MeV electrons emitted by 90Sr,Y collimated radioactive source demonstrate that the charge collected by the active volume saturates at 1.00±0.02 fC at an electric field strength evaluated as ±1.3 V/m with electrons impinging parallel to the rows. The collected charge, much lower than that expected by theoretical estimation, has been tentatively attributed to a loss of biasing due to the probable non-continuity of the graphite pillars within the sample.

OBJECTIVE Glucose-stimulated islet insulin or C-peptide secretion experiments are a fundamental tool for studying and assessing islet function. The goal of this work was to develop Ab-based fluorescent homogenous sensors that would allow rapid, inexpensive, near-instantaneous determinations of insulin and C-peptide levels in biological samples. RESEARCH DESIGN AND METHODS Our approach was to use molecular pincer design (Heyduk et al., Anal Chem 2008;80:5152–5159) in which a pair of antibodies recognizing nonoverlapping epitopes of the target are modified with short fluorochrome-labeled complementary oligonucleotides and are used to generate a fluorescence energy transfer (FRET) signal in the presence of insulin or C-peptide. RESULTS The sensors were capable of detecting insulin and C-peptide with high specificity and with picomolar concentration detection limits in times as short as 20 min. Insulin and C-peptide levels determined with the FRET sensors showed outstanding correlation with determinations performed under the same conditions with enzyme-linked immunosorbent assay. Most importantly, the sensors were capable of rapid and accurate determinations of insulin and C-peptide secreted from human or rodent islets, verifying their applicability for rapid assessment of islet function. CONCLUSIONS The homogeneous, rapid, and uncomplicated nature of insulin and C-peptide FRET sensors allows rapid assessment of β-cell function and could enable point-of-care determinations of insulin and C-peptide.

During the initial autoimmune response in type 1 diabetes, islets are exposed to a damaging mix of pro-inflammatory molecules that stimulate the production of nitric oxide by beta-cells. Nitric oxide causes extensive but reversible cellular damage. In response to nitric oxide, the cell activates pathways for functional recovery and adaptation as well as pathways that direct beta-cell death. The molecular events that dictate cellular fate following nitric oxide-induced damage are currently unknown. In this study, we provide evidence that AMPK plays a primary role controlling the response of beta-cells to nitric oxide-induced damage. AMPK is transiently activated by nitric oxide in insulinoma cells and rat islets following IL-1 treatment or by the exogenous addition of nitric oxide. Active AMPK promotes the functional recovery of beta-cell oxidative metabolism and abrogates the induction of pathways that mediate cell death such as caspase-3 activation following exposure to nitric oxide. Overall, these data show that nitric oxide activates AMPK and that active AMPK suppresses apoptotic signaling allowing the beta-cell to recover from nitric oxide-mediated cellular stress.

The Human Genome Project provided the opportunity to use bioinformatic approaches to discover novel, endogenous hormones. Using this approach we have identified two novel peptide hormones and review here our strategy for the identification and characterization of the hormone, neuronostatin. We describe in this mini-review our strategy for determining neuronostatin's actions in brain, heart and pancreas. More importantly, we detail our deductive reasoning strategy for the identification of a neuronostatin receptor and our progress in establishing the physiological relevance of the peptide.

Parallel follow-up of clinical and inflammatory markers during sub-lingual immunotherapy (SLIT) is highly beneficial. Twenty-four children (age 4-16) monosensitized to house dust mite were randomized to receive either active or placebo SLIT for 1 yr in a double-blind placebo controlled design (Marcucci et al., Allergy 2003: 58: 657-62). Thereafter, for 2 yr they all received active treatment. Symptom scores for rhinitis, asthma, and drug usage were daily recorded. Eosinophil cationic protein (ECP) and tryptase in sputum and nasal secretions, serum and nasal mite-specific immunoglobulin E (IgE) were recorded before treatment and at 10-12 months intervals. Nasal ECP and nasal tryptase after specific nasal provocation tests were significantly reduced as compared to baseline values (p = 0.0043 and 0.0195, respectively) in the third year of active treatment. None of the other inflammatory parameters was increased. In placebo treated patients all these parameters tended to decrease only after switching to active treatment. Clinical scores did not improve in treated vs. placebo patients in the double-blind placebo-controlled phase of the study. In both cohorts a clinical benefit was observed as intra-group score reduction as compared to baseline. A significant difference was reached in patients treated for 2 yr for rhinitis and asthma (p = 0.0009 and 0.0019, respectively) but not for drug usage and in patients treated for 3 yr for rhinitis, asthma, and drug usage (p = 0.0105, 0.0048, and 0.02, respectively). SLIT in children monosensitized to mites reverted the spontaneous increase in nasal IgE and in local parameters of allergic inflammation. These outcomes were followed by a consolidated clinical improvement in the second and third year of treatment.

This work reports on the realization and test of a compact beam-profiling system for UV and X-ray sources, based on polycrystalline CVD diamond detectors. Multistrip and pixel structures have been used for 1-D and 2-D photodetectors, respectively. A dedicated read-out electronic circuitry has been designed and used to independently sample the signal produced by each strip (or pixel), enabling a real-time beam profile reconstruction.

The charge collection performance of a diamond-graphite detector is reported. Buried graphite pillars with high aspect ratio were formed inside a single crystal synthetic diamond slab by using a femtosecond IR laser with 200 kHz of repetition rate. Grouped in two series and connected by graphite strips on the surface, eight independent 3D electrodes were used to collect the charge carriers generated by energy deposited in the detector. Collimated 90Sr,Y β -particles were used to test the charge collection in coincidence and self-triggering mode among pillars rows using different irradiation geometries. The charge collected by one pillar row saturates at 1.40±0.02 fC at ±0.67V/ μ m with electrons impinging orthogonally the rows demonstrating a high charge carrier collection efficiency. Key

Pulsed laser deposition of carbon-based materials has been explored in order to obtain cold cathode flat emitters with high emission current density and low threshold field, and to examine the factors controlling the electron field emission behaviour. In this paper, results on amorphous carbon thin films deposited on silicon by pulsed laser ablation (PLA) from a graphite target, using a KrF excimer laser are presented. The structure and surface morphology of carbon materials have been examined by transmission electron microscopy (TEM) and Raman spectroscopy. I – V characteristics of the carbon films have been measured by a diode technique (below 10 −4 Pa). Some effects of the deposition parameters on thin film uniformity, adhesion, and field emission performances have been investigated. Emission current density as high as 50 mA/cm 2 at an electric field of 70 V/μm has been obtained on 100 nm thick, smooth and glassy carbon films deposited at 150 °C.

This paper discusses guidelines that emphasize the relevance of short-circuit- and open-circuit-time constant (SCTC and OCTC, respectively) methods in the analysis and design of electronic amplifiers. It is demonstrated that it is only necessary to grasp a few concepts in order to understand that the two short- and open-circuit cases fall into a single case that can be easily addressed by low-pass and high-pass filters duality. Instead of just teaching the methods as ldquorecipesrdquo for frequency-performance systems analysis, SCTC and OCTC can be efficiently explained in basic analog electronic courses so as to elucidate their underlying principles. The discussion presented here will include two analysis and design examples, used to highlight the benefits gained by the approximated analysis technique, as well as a section that examines the accuracy of the technique.

Neuronostatin is a recently described peptide hormone encoded by the somatostatin gene. We previously showed that intraperitoneal injection of neuronostatin into mice resulted in c-Jun accumulation in pancreatic islets in a pattern consistent with the activation of glucagon-producing α-cells. We therefore hypothesized that neuronostatin could influence glucose homeostasis via a direct effect on the α-cell. Neuronostatin enhanced low-glucose-induced glucagon release in isolated rat islets and in the immortalized α-cell line αTC1-9. Furthermore, incubation with neuronostatin led to an increase in transcription of glucagon mRNA, as determined by RT-PCR. Neuronostatin also inhibited glucose-stimulated insulin secretion from isolated islets. However, neuronostatin did not alter insulin release from the β-cell line INS 832/13, indicating that the effect of neuronostatin on insulin secretion may be secondary to a direct action on the α-cell. In agreement with our in vitro data, intra-arterial infusion of neuronostatin in male rats delayed glucose disposal and inhibited insulin release during a glucose challenge. These studies suggest that neuronostatin participates in maintaining glucose homeostasis through cell-cell interactions between α-cells and β-cells in the endocrine pancreas, leading to attenuation in insulin secretion.

Neuronostatin (NST) is produced in pancreatic delta cells from the somatostatin preprohormone, and has been shown to inhibit glucose-stimulated insulin secretion from beta cells of primary islets, but not from isolated beta cell cultures. We have demonstrated that NST stimulates glucagon release and have hypothesized that this is necessary for the peptide’s in vivo effect to impair glucose tolerance. Here we demonstrate the action of NST to increase proglucagon message in alpha cells and identify a potential mechanism to be via phosphorylation of protein kinase A. The NST receptor, GPR107, is abundantly expressed in the pancreas, in particular in the alpha cell population and both the effect on proglucagon mRNA levels and PKA phosphrylation are absent in alpha cells in which the expression of the NST receptor has been compromised using siRNA. Taken together with our observation that NST infusion in conscious rats impairs glucose tolerance and that plasma levels of the peptide are elevated in the fasted co...

The photoconductive dynamic response of AlGaN based UV detectors to 193 nm excimer laser radiation is presented. Two different devices have been realized, tested and compared: a metal–semiconductor–metal (MSM) planar structure and a Schottky diode. The capability of these devices to detect the emission of a nanosecond pulsed excimer laser is proven and the decay time and dependency on the beam’s density of energy evaluated. The transient response of the MSM device closely follows the laser pulse, with a photoconductive decay time shorter than 3 ns. On the contrary, the Schottky diode shows a slower photoconductive rise and decay kinetics due to the material series resistance coupled with the junction capacitance. Moreover, a longer time constant tail is also evident in this case with a characteristic decay time of about 40 ns, due to the presence of trap states localized at 0.2–0.3 eV from the band edge. The detection dynamics has been evaluated by changing the beam intensity between 2 × 10−5 and 0.2 mJ/mm2. The signal increases linearly in the case of the MSM device up to 0.002 mJ/mm2 whereas, for a further intensity rise, the response becomes prone to a sub-linear behavior. On the contrary, the Schottky diode showed a linear trend below 2 × 10−2 mJ/mm2.

Myotonic dystrophy (DM; OMIM 160900, also known as dystrophia myotonica, myotonia atrophica and Steinert disease) is an autosomal dominant myotonic myopathy associated with abnormalities of other organs, including eyes, heart, endocrine system, central and peripheral nervous systems, gastrointestinal organs, bone, and skin.1 The mutation underlying DM is an expansion of an unstable cytosine-thymine-guanine (CTG) trinucleotide repeat in the 3' untranslated region of the myotonic dystrophy protein kinase (DMPK) gene in chromosome 19q13.3.2-4 In 1994, Thornton et al.5 described an autosomal dominant disorder similar to DM without CTG repeat expansion at the DM locus. Ricker et al.6 named this disease "proximal myotonic myopathy" (PROMM; OMIM 600109) because of predominantly proximal muscle weakness without atrophy as opposed to the distal muscle involvement seen in DM. Subsequently, Meola et al.7 described a variant of PROMM with unusual myotonic and myopathic features, which they named "proximal myotonic myopathy syndrome," and Udd et al.8 described a PROMM-like family with dystrophic features, which they named "proximal myotonic dystrophy" (PDM). Researchers at the University of Minnesota9,10 found another multisystemic myotonic disorder that closely resembles DM with distal muscle weakness but no CTG repeat expansion. Because of the close phenotypic resemblance to DM, they called this disease "myotonic dystrophy type 2" (DM2; OMIM 602668). In 1998, Ranum et al.9 assigned the DM2 locus to chromosome 3q in a large kindred. Shortly after that, Ricker et al.11 found that the majority of German PROMM families show linkage to the DM2 locus. PDM was also mapped to this region (Krahe and Udd, personal communication, 1999). Whether PROMM, PDM, and DM2 represent different phenotypic expressions of a disease caused by the same mutation or if they are allelic disorders remains to be determined. It is also possible that these disorders are caused by mutations in different genes that are closely linked in the chromosome 3q region.12 Furthermore, the disease loci in some typical PROMM families11 and other families with multisystemic myotonic disorders have been excluded from both DM and DM2 loci. Because of the genetic and phenotypic heterogeneity in this group of disorders, it became necessary to establish a new nomenclature foreseeing the future discovery of new disease loci and phenotypic variability.

Type 1 diabetes results from autoimmune destruction of the insulin producing pancreatic β-cells. The immunoproteasome, a version of the proteasome that collaborates with the 11S/PA28 activator to generate immunogenic peptides for presentation by MHC class I molecules, has long been implicated in the onset of the disease, but little is known about immunoproteasome function and regulation in pancreatic β-cells. Interesting insight into these issues comes from a recent analysis of the immunoproteasome expressed in pancreatic β-cells during early antiviral defenses mediated by interferon β (IFNβ), a type I IFN implicated in the induction of the diabetic state in human and animal models. Using mouse islets and the MIN6 insulinoma cell line, Freudenburg et al. found that IFNβ stimulates expression of the immunoproteasome and the 11S/PA28 activator in a manner fundamentally similar to the classic immuno-inducer IFNγ, with similar timing of mRNA accumulation and decline; similar transcriptional activation mediated primarily by the IRF1 and similar mRNA and protein levels. Furthermore, neither IFNβ nor IFNγ altered the expression of regular proteolytic subunits or prevented their incorporation into proteolytic cores. As a result, immunoproteasomes had stochastic combinations of immune and regular proteolytic sites, an arrangement that would likely increase the probability with which unique immunogenic peptides are produced. However, immunoproteasomes were activated by the 11S/PA28 only under conditions of ATP depletion. A mechanism that prevents the activation of immunoproteasome at high ATP levels has not been reported before and could have a major regulatory significance, as it could suppress the generation of immunogenic peptides as cell accumulate immunoproteasome and 11S/PA28, and activate antigen processing only when ATP levels drop. We discuss implications of these new findings on the link between early antiviral response and the onset of type 1 diabetes.

The activation of the transcription factor NF-κB leads to changes in expression of many genes in pancreatic β-cells. However, the role of NF-κB activation in islet transplantation has not been fully elucidated. The aim of the present study was to investigate whether the state of NF-κB activation would influence the outcome of islet transplantation. Transgenic mice expressing a dominant active IKKβ (constitutively active) or a non-degradable form of IκBα (constitutive inhibition) under control of the rat insulin promoter were generated. Islets from these mice were transplanted into streptozotocin diabetic mice in suboptimal numbers. Further, the effects of salicylate (an inhibitor of NF-κB) treatment of normal islets prior to transplantation, and the effects of salicylate administration to mice prior to and after islet implantation were evaluated. Transplantation outcomes were not affected using islets expressing a non-degradable form of IκBα when compared to wild type controls. However, the transplantation outcomes using islets isolated from mice expressing a constitutively active mutant of NF-κB were marginally worse, although no aberrations of islet function in vitro could be detected. Salicylate treatment of normal islets or mice had no effect on transplantation outcome. The current study draws attention to the complexities of NF-κB in pancreatic beta cells by suggesting that they can adapt with normal or near normal function to both chronic activation and inhibition of this important transcription factor.

Autoimmune destruction of insulin producing pancreatic β-cells is the hallmark of type I diabetes. One of the key molecules implicated in the disease onset is the immunoproteasome, a protease with multiple proteolytic sites that collaborates with the constitutive 19S and the inducible 11S (PA28) activators to produce immunogenic peptides for presentation by MHC class I molecules. Despite its importance, little is known about the function and regulation of the immunoproteasome in pancreatic β-cells. Of special interest to immunoproteasome activation in β-cells are the effects of IFNβ, a type I IFN secreted by virus-infected cells and implicated in type I diabetes onset, compared to IFNγ, the classic immunoproteasome inducer secreted by cells of the immune system. By qPCR analysis, we show that mouse insulinoma MIN6 cells and mouse islets accumulate the immune proteolytic β1(i), β2(i) and β5(i), and 11S mRNAs upon exposure to IFNβ or IFNγ. Higher concentrations of IFNβ than IFNγ are needed for similar expression, but in each case the expression is transient, with maximal mRNA accumulation in 12 hours, and depends primarily on Interferon Regulatory Factor 1. IFNs do not alter expression of regular proteasome genes, and in the time frame of IFNβ-mediated response, the immune and regular proteolytic subunits co-exist in the 20S particles. In cell extracts with ATP, these particles have normal peptidase activities and degrade polyubiquitinated proteins with rates typical of the regular proteasome, implicating normal regulation by the 19S activator. However, ATP depletion rapidly stimulates the catalytic rates in a manner consistent with levels of the 11S activator. These findings suggest that stochastic combination of regular and immune proteolytic subunits may increase the probability with which unique immunogenic peptides are produced in pancreatic β-cells exposed to IFNβ, but primarily in cells with reduced ATP levels that stimulate the 11S participation in immunoproteasome function.