Publications by authors named "Putnam C"

The mutants designated (cell lysis) cause cell lysis at elevated temperatures. The mutation, previously localized to an 80 kilobase region between and on the right arm of chromosome VII, has been used for mutation mapping and in recombination assays, but its genetic identity has remained unknown. Whole genome sequencing of mutant and wild-type strains revealed four missense mutations specific to the mutant strain in the - interval, three of these missense mutations affected essential genes.

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Inflammation has an essential role in healing. However, over-active inflammation disrupts normal cellular functions and can be life-threatening when not resolved. The NLRP3 inflammasome, a component of the innate immune system, is an intracellular multiprotein complex that senses stress-associated signals, and, for this reason is a promising therapeutic target for treating unresolved, pathogenic inflammation.

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Introduction: Transplantation of kidneys from expanded criteria donors (ECD), including after circulatory death (DCD), is associated with a higher risk of adverse events compared to kidneys from standard criteria donors. In previous studies, improvements in renal transplant outcomes have been seen when kidneys were perfused with gaseous oxygen during preservation (persufflation, PSF). In the present study, we assessed ex-vivo renal function from a Diffusion Contrast Enhanced (DCE)-MRI estimation of glomerular filtration rate (eGFR); and metabolic sufficiency from whole-organ oxygen consumption (WOOCR) and lactate production rates.

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Introduction: Conventional culture conditions, such as in T-flasks, require that oxygen diffuse through the medium to reach the islets; in turn, islet surface area density is limited by oxygen availability. To culture a typical clinical islet preparation may require more than 20 T-175 flasks at the standard surface area density of 200 IE/cm. To circumvent this logistical constraint, we tested islets cultured on top of silicon gas-permeable (GP) membranes which place islets in close proximity to ambient oxygen.

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Introduction: Subcutaneous macroencapsulation devices circumvent disadvantages of intraportal islet therapy. However, a curative dose of islets within reasonably sized devices requires dense cell packing. We measured internal PO2 of implanted devices, mathematically modeled oxygen availability within devices and tested the predictions with implanted devices containing densely packed human islets.

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DNA content measurement by fluorescence-assisted cell sorting (FACS) provides information on cell cycle progression and DNA content variability. mutants with DNA content variability that was reduced relative to wild-type strains had defects in mitochondrial DNA (mtDNA) maintenance and mitochondrial gene expression and were correlated with strains found to lack mtDNA ([ ] cells) by genome sequencing and fluorescence microscopy. In contrast, mutants with increased variability had defects in cell cycle progression, which may indicate a loss of coordination between mtDNA and nuclear DNA replication.

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Cellular pathways that detect DNA damage are useful for identifying genes that suppress DNA damage, which can cause genome instability and cancer predisposition syndromes when mutated. We identified 199 high-confidence and 530 low-confidence DNA damage-suppressing (DDS) genes in Saccharomyces cerevisiae through a whole-genome screen for mutations inducing Hug1 expression, a focused screen for mutations inducing Ddc2 foci, and data from previous screens for mutations causing Rad52 foci accumulation and Rnr3 induction. We also identified 286 high-confidence and 394 low-confidence diverse genome instability-suppressing (DGIS) genes through a whole-genome screen for mutations resulting in increased gross chromosomal rearrangements and data from previous screens for mutations causing increased genome instability as assessed in a diversity of genome instability assays.

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From studies of individual families to global collaborative efforts, the NLRP3 inflammasome is now recognized to be a key regulator of innate immunity. Activated by a panoply of pathogen-associated and endogenous triggers, NLRP3 serves as an intracellular sensor that drives carefully coordinated assembly of the inflammasome, and downstream inflammation mediated by IL-1 and IL-18. Initially discovered as the cause of the autoinflammatory spectrum of cryopyrin-associated periodic syndrome (CAPS), NLRP3 is now also known to play a role in more common diseases including cardiovascular disease, gout, and liver disease.

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Modulating the immune system to treat diseases, including myeloid malignancies, has resulted in the development of a multitude of novel therapeutics in recent years. Myelodysplastic syndromes or neoplasms (MDS) and acute myeloid leukemia (AML) are hematologic malignancies that arise from defects in hematopoietic stem and progenitor cells (HSPCs). Dysregulated immune responses, especially in innate immune and inflammatory pathways, are highly associated with the acquisition of HSPC defects in MDS and AML pathogenesis.

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MutL family proteins contain an N-terminal ATPase domain (NTD), an unstructured interdomain linker, and a C-terminal domain (CTD), which mediates constitutive dimerization between subunits and often contains an endonuclease active site. Most MutL homologs direct strand-specific DNA mismatch repair by cleaving the error-containing daughter DNA strand. The strand cleavage reaction is poorly understood; however, the structure of the endonuclease active site is consistent with a two- or three-metal ion cleavage mechanism.

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In Type 1 diabetes patients, even ultra-rapid acting insulins injected subcutaneously reach peak concentrations in 45 minutes or longer. The lag time between dosing and peak concentration, as well as intra- and inter-subject variability, render prandial glucose control and dose consistency difficult. We postulated that insulin absorption from subcutaneously implantable vascularizing microchambers would be significantly faster than conventional subcutaneous injection.

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Background: Disabling pansclerotic morphea (DPM) is a rare systemic inflammatory disorder, characterized by poor wound healing, fibrosis, cytopenias, hypogammaglobulinemia, and squamous-cell carcinoma. The cause is unknown, and mortality is high.

Methods: We evaluated four patients from three unrelated families with an autosomal dominant pattern of inheritance of DPM.

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Transplants comprised of encapsulated islets have shown promise in treating insulin-dependent diabetes. A question raised in the scientific and clinical communities is whether the insulin released from an implanted encapsulation device damaged in an accident could cause a serious hypoglycemic event. In this commentary, we consider the different types of damage that a device can sustain, including the encapsulation membrane and the islets within, and the amount of insulin released in each case.

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Eukaryotic DNA mismatch repair (MMR) depends on recruitment of the Mlh1-Pms1 endonuclease (human MLH1-PMS2) to mispaired DNA. Both Mlh1 and Pms1 contain a long unstructured linker that connects the N- and carboxyl-terminal domains. Here, we demonstrated the Mlh1 linker contains a conserved motif ( residues 391-415) required for MMR.

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Eukaryotic DNA mismatch repair (MMR) initiates through mispair recognition by the MutS homologs Msh2-Msh6 and Msh2-Msh3 and subsequent recruitment of the MutL homologs Mlh1-Pms1 (human MLH1-PMS2). In bacteria, MutL is recruited by interactions with the connector domain of one MutS subunit and the ATPase and core domains of the other MutS subunit. Analysis of the S.

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DNA topoisomerases are essential enzymes that stabilize DNA supercoiling and resolve entanglements. Topoisomerase inhibitors have been widely used as anti-cancer drugs for the past 20 years. Due to their selectivity as topoisomerase I (TOP1) inhibitors that trap TOP1 cleavage complexes, camptothecin and its derivatives are promising anti-cancer drugs.

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DNA mismatch repair (MMR) repairs replication errors, and MMR defects play a role in both inherited cancer predisposition syndromes and in sporadic cancers. MMR also recognizes mispairs caused by environmental and chemotherapeutic agents; however, in these cases mispair recognition leads to apoptosis and not repair. Although mutation avoidance by MMR is fairly well understood, MMR-associated proteins are still being identified.

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Background: Hoffman syndrome is a syndromic, inborn error of immunity due to autosomal-dominant mutations in TOP2B, an essential gene required to alleviate topological stress during DNA replication and gene transcription. Although mutations identified in patients lead to a block in B-cell development and the absence of circulating B cells, an effect on natural killer (NK) cells was not previously examined.

Objective: We sought to determine whether disease-associated mutations in TOP2B impact NK-cell development and function.

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Eukaryotic DNA Mismatch Repair (MMR) involves redundant exonuclease 1 (Exo1)-dependent and Exo1-independent pathways, of which the Exo1-independent pathway(s) is not well understood. The exo1Δ440-702 mutation, which deletes the MutS Homolog 2 (Msh2) and MutL Homolog 1 (Mlh1) interacting peptides (SHIP and MIP boxes, respectively), eliminates the Exo1 MMR functions but is not lethal in combination with rad27Δ mutations. Analyzing the effect of different combinations of the exo1Δ440-702 mutation, a rad27Δ mutation and the pms1-A99V mutation, which inactivates an Exo1-independent MMR pathway, demonstrated that each of these mutations inactivates a different MMR pathway.

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Cancer patients who are overweight compared to those with normal body weight have obesity-associated alterations of natural killer (NK) cells, characterized by poor cytotoxicity, slow proliferation, and inadequate anti-cancer activity. Concomitantly, prohibitin overexpressed by cancer cells elevates glucose metabolism, rendering the tumor microenvironment (TME) more tumor-favorable, and leading to malfunction of immune cells present in the TME. These changes cause vicious cycles of tumor growth.

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DNA mismatch repair (MMR) corrects non-Watson-Crick basepairs generated by replication errors, recombination intermediates, and some forms of chemical damage to DNA. In MutS and MutL homolog-dependent MMR, damaged bases do not identify the error-containing daughter strand that must be excised and resynthesized. In organisms like Escherichia coli that use methyl-directed MMR, transient undermethylation identifies the daughter strand.

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Shaft-only phalloplasty (SOP) has been described as an alternative option for phalloplasty. Although traditional phalloplasty represents the most complete form of genital gender-affirming surgery, this variation also carries the greatest surgical risk. Patients may opt for a lower risk SOP for reasons including gender identity, gender expression, sexual function, desire for future childbearing, or minimal gender dysphoria associated with sedentary urination.

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Background: Evidence bearing on the role of statins in the prevention and treatment of cancer is confounded by the diversity of statins, chemotherapeutic agents and cancer types included in the numerous published studies; consequently, the adjunctive value of statins with chemotherapy remains uncertain.

Methods: We assayed lovastatin in combination with each of ten commonly prescribed chemotherapy drugs in highly reproducible in vitro assays, using a neutral cellular substrate, Saccharomyces cerevisiae. Cell density (OD) data were analyzed for synergism and antagonism using the Loewe additivity model implemented with the Combenefit software.

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Inborn errors of immunity (IEI) are a genetically heterogeneous group of disorders with a broad clinical spectrum. Identification of molecular and functional bases of these disorders is important for diagnosis, treatment, and an understanding of the human immune response. We identified 6 unrelated males with neutropenia, infections, lymphoproliferation, humoral immune defects, and in some cases bone marrow failure associated with 3 different variants in the X-linked gene TLR8, encoding the endosomal Toll-like receptor 8 (TLR8).

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