Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Leonidas G. Koniaris is active.

Publication


Featured researches published by Leonidas G. Koniaris.


Journal of Gastrointestinal Surgery | 2000

Resected adenocarcinoma of the pancreas— 616 patients: Results, outcomes, and prognostic indicators

Taylor A. Sohn; Charles J. Yeo; John L. Cameron; Leonidas G. Koniaris; Sunjay Kaushal; Ross A. Abrams; Patricia K. Sauter; JoAnn Coleman; Ralph H. Hruban; Keith D. Lillemoe

This large-volume, single-institution review examines factors influencing long-term survival after resection in patients with adenocarcinoma of the head, neck, uncinate process, body, or tail of the pancreas. Between January 1984 and July 1999 inclusive, 616 patients with adenocarcinoma of the pancreas underwent surgical resection. A retrospective analysis of a prospectively collected database was performed. Both univariate and multivariate models were used to determine the factors influencing survival. Of the 616 patients, 526 (85%) underwent pancreaticoduodenectomy for adenocarcinoma of the head, neck, or uncinate process of the pancreas, 52 (9%) underwent distal pancreatectomy for adenocarcinoma of the body or tail, and 38 (6%) underwent total pancreatectomy for adenocarcinoma extensively involving the gland. The mean age of the patients was 64.3 years, with 54% being male and 91% being white. The overall perioperative mortality rate was 2.3%, whereas the incidence of postoperative complications was 30%. The median postoperative length of stay was 11 days. The mean tumor diameter was 3.2 cm, with 72 % of patients having positive lymph nodes, 30% having positive resection margins, and 36% having poorly differentiated tumors. Patients undergoing distal pancreatectomy for left-sided lesions had larger tumors (4.7 vs. 3.1 cm, P <0.0001), but fewer node-positive resections (59% vs. 73%, P = 0.03) and fewer poorly differentiated tumors (29% vs. 36%, P<0.001), as compared to those undergoing pancreaticoduodenectomy for right-sided lesions. The overall survival of the entire cohort was 63% at 1 year and 17% at 5 years, with a median survival of 17 months. For right-sided lesions the 1- and 5-year survival rates were 64% and 17%, respectively, compared to 50% and 15% for left-sided lesions. Factors shown to have favorable independent prognostic significance by multivariate analysis were negative resection margins (hazard ratio [HR] = 0.64, confidence interval [CI] = 0.50 to 0.82, P = 0.0004), tumor diameter less than 3 cm (HR = 0.72, CI = 0.57 to 0.90, P = 0.004), estimated blood loss less than 750 ml (HR = 0.75, CI = 0.58 to 0.96, P = 0.02), well/moderate tumor differentiation (HR = 0.71, CI = 0.56 to 0.90, P = 0.005), and postoperative chemoradiation (HR = 0.50, CI = 0.39 to 0.64, P } < 0.0001). Tumor location in head, neck, or uncinate process approached significance in the final multivariate model (HR = 0.60, CI = 0.35 to 1.0, P = 0.06). Pancreatic resection remains the only hope for long-term survival in patients with adenocarcinoma of the pancreas. Completeness of resection and tumor characteristics including tumor size and degree of differentiation are important independent prognostic indicators. Adjuvant chemoradiation is a strong predictor of outcome and likely decreases the independent significance of tumor location and nodal status.


Journal of Surgical Research | 2009

Pediatric Thyroid Carcinoma: Incidence and Outcomes in 1753 Patients

Anthony R. Hogan; Ying Zhuge; Eduardo A. Perez; Leonidas G. Koniaris; John I. Lew; Juan E. Sola

OBJECTIVE To examine outcomes and predictors of survival for pediatric patients with thyroid carcinoma. METHODS The Surveillance, Epidemiology, and End Results (SEER) registry from 1973 to 2004 was queried for all patients with thyroid carcinoma less than 20 y of age. RESULTS A total of 1753 patients with malignant thyroid neoplasms were identified with an age-adjusted annual incidence of 0.54 cases per 100,000 persons. There has been a significant increase in the annual incidence by 1.1% per y. Female patients outnumbered males 4 to 1. Tumors were classified as papillary (n=1044, 60%), follicular variant of papillary (n=389, 23%), follicular (n=165, 10%), and medullary (n=87, 5%). The majority of patients presented with localized and regional disease. Overall mean survival time (MST) was 30.5 y. The MST for females was 40 y, whereas males survived an average of 20.4 y (P=0.0001). Patients with medullary cancer had significantly shorter mean survival than those with papillary cancer (P=0.006). Surgical treatment significantly improved outcome. Multivariate analysis demonstrated that male gender, nonpapillary histology, distant disease, and no surgery were all independent prognostic factors of worse outcome. For patients with medullary thyroid carcinoma, radiation therapy was also identified as an independent predictor of lower survival. CONCLUSION The incidence of pediatric thyroid cancer is increasing. Females have a higher incidence than males, but enjoy longer survival. Papillary thyroid cancer has overall excellent survival. Male gender, nonpapillary tumor, distant metastases, and nonsurgical treatment all predict worse outcome.


Annals of Surgery | 2007

Should soft tissue sarcomas be treated at high-volume centers? An analysis of 4205 patients

Juan C. Gutierrez; Eduardo A. Perez; Frederick L. Moffat; Alan S. Livingstone; Dido Franceschi; Leonidas G. Koniaris

Objective:To define the prognostic significance of surgical center case volume on outcome for soft tissue sarcoma (STS). Methods:STS cases registered in the Florida Cancer Data System (FCDS) between 1981 and 2001 were analyzed. Medical facilities were ranked by STS operative volume. Facilities above the 67th percentile for volume were defined as high-volume centers (HVCs). Results:Of the 4205 operative cases of STS identified, 68.1% were treated at low-volume centers (LVCs) and 31.9% at HVCs. A larger proportion of high-grade tumors (53.8% vs. 44.3%) and lesions over 10 cm (40.7% vs. 28.7%) were resected at HVC (P < 0.001). The 30-day mortality was 0.7% for HVC and 1.5% for LVC (P = 0.028), and mortality rates at 90 days were 1.6% and 3.6%, respectively (P = 0.001). Median survival was 40 months at HVC and 37 months at LVC (P = 0.002). Univariate analysis demonstrated significantly improved survival at HVC for high-grade tumors (median 30 months vs. 24 months, P = 0.001), lesions over 10 cm (28 months vs. 19 months, P = 0.001) and truncal or retroperitoneal sarcomas (39 months vs. 31 months, P = 0.011). Limb amputation rate was lower (9.4% vs. 13.8%, P = 0.048) and radiation and chemotherapy were more frequently administered at HVC (OR = 1.54). On multivariate analysis, treatment at a HVC was a significant independent predictor of improved survival (OR = 1.292, P = 0.047). Conclusions:STS patients treated at HVC have significantly better survival and functional outcomes. Patients with either large (>10 cm), high-grade or truncal/retroperitoneal tumors should be treated exclusively at a high-volume center.


Molecular and Cellular Biology | 2000

Characterization of Growth-Differentiation Factor 15, a Transforming Growth Factor β Superfamily Member Induced following Liver Injury

Edward C. Hsiao; Leonidas G. Koniaris; Teresa Zimmers-Koniaris; Suzanne Sebald; Thanh V. Huynh; Se-Jin Lee

ABSTRACT We have identified a new murine transforming growth factor β superfamily member, growth-differentiation factor 15 (Gdf15), that is expressed at highest levels in adult liver. As determined by Northern analysis, the expression ofGdf15 in liver was rapidly and dramatically up-regulated following various surgical and chemical treatments that cause acute liver injury and regeneration. In situ hybridization analysis revealed distinct patterns of Gdf15 mRNA localization that appeared to reflect the known patterns of hepatocyte injury in each experimental treatment. In addition, treatment of two hepatocyte-like cell lines with either carbon tetrachloride or heat shock inducedGdf15 mRNA expression, indicating that direct cellular injury can induce Gdf15 expression in the absence of other cell types, such as inflammatory cells. In order to investigate the potential functions of Gdf15, we created Gdf15 null mice by gene targeting. Homozygous null mice were viable and fertile. Despite the dramatic regulation of Gdf15 expression observed in the partial-hepatectomy and carbon tetrachloride injury models, we found no differences in the injury responses between homozygous null mutants and wild-type mice. Our findings suggest either that Gdf15 does not have a regulatory role in liver injury and regeneration or that Gdf15 function within the liver is redundant with that of other signaling molecules.


Biochemical and Biophysical Research Communications | 2010

Acute inhibition of myostatin-family proteins preserves skeletal muscle in mouse models of cancer cachexia

Margaret E. Benny Klimek; Tufan Aydogdu; Majik Link; Marianne Pons; Leonidas G. Koniaris; Teresa A. Zimmers

Cachexia, progressive loss of fat and muscle mass despite adequate nutrition, is a devastating complication of cancer associated with poor quality of life and increased mortality. Myostatin is a potent tonic muscle growth inhibitor. We tested how myostatin inhibition might influence cancer cachexia using genetic and pharmacological approaches. First, hypermuscular myostatin null mice were injected with Lewis lung carcinoma or B16F10 melanoma cells. Myostatin null mice were more sensitive to tumor-induced cachexia, losing more absolute mass and proportionately more muscle mass than wild-type mice. Because myostatin null mice lack expression from development, however, we also sought to manipulate myostatin acutely. The histone deacetylase inhibitor Trichostatin A has been shown to increase muscle mass in normal and dystrophic mice by inducing the myostatin inhibitor, follistatin. Although Trichostatin A administration induced muscle growth in normal mice, it failed to preserve muscle in colon-26 cancer cachexia. Finally we sought to inhibit myostatin and related ligands by administration of the Activin receptor extracellular domain/Fc fusion protein, ACVR2B-Fc. Systemic administration of ACVR2B-Fc potently inhibited muscle wasting and protected adipose stores in both colon-26 and Lewis lung carcinoma cachexia, without affecting tumor growth. Enhanced cachexia in myostatin knockouts indicates that host-derived myostatin is not the sole mediator of muscle wasting in cancer. More importantly, skeletal muscle preservation with ACVR2B-Fc establishes that targeting myostatin-family ligands using ACVR2B-Fc or related molecules is an important and potent therapeutic avenue in cancer cachexia.


PLOS ONE | 2011

STAT3 Activation in Skeletal Muscle Links Muscle Wasting and the Acute Phase Response in Cancer Cachexia

Andrea Bonetto; Tufan Aydogdu; Noelia J. Kunzevitzky; Denis C. Guttridge; Sawsan Khuri; Leonidas G. Koniaris; Teresa A. Zimmers

Background Cachexia, or weight loss despite adequate nutrition, significantly impairs quality of life and response to therapy in cancer patients. In cancer patients, skeletal muscle wasting, weight loss and mortality are all positively associated with increased serum cytokines, particularly Interleukin-6 (IL-6), and the presence of the acute phase response. Acute phase proteins, including fibrinogen and serum amyloid A (SAA) are synthesized by hepatocytes in response to IL-6 as part of the innate immune response. To gain insight into the relationships among these observations, we studied mice with moderate and severe Colon-26 (C26)-carcinoma cachexia. Methodology/Principal Findings Moderate and severe C26 cachexia was associated with high serum IL-6 and IL-6 family cytokines and highly similar patterns of skeletal muscle gene expression. The top canonical pathways up-regulated in both were the complement/coagulation cascade, proteasome, MAPK signaling, and the IL-6 and STAT3 pathways. Cachexia was associated with increased muscle pY705-STAT3 and increased STAT3 localization in myonuclei. STAT3 target genes, including SOCS3 mRNA and acute phase response proteins, were highly induced in cachectic muscle. IL-6 treatment and STAT3 activation both also induced fibrinogen in cultured C2C12 myotubes. Quantitation of muscle versus liver fibrinogen and SAA protein levels indicates that muscle contributes a large fraction of serum acute phase proteins in cancer. Conclusions/Significance These results suggest that the STAT3 transcriptome is a major mechanism for wasting in cancer. Through IL-6/STAT3 activation, skeletal muscle is induced to synthesize acute phase proteins, thus establishing a molecular link between the observations of high IL-6, increased acute phase response proteins and muscle wasting in cancer. These results suggest a mechanism by which STAT3 might causally influence muscle wasting by altering the profile of genes expressed and translated in muscle such that amino acids liberated by increased proteolysis in cachexia are synthesized into acute phase proteins and exported into the blood.


American Journal of Physiology-endocrinology and Metabolism | 2012

JAK/STAT3 pathway inhibition blocks skeletal muscle wasting downstream of IL-6 and in experimental cancer cachexia

Andrea Bonetto; Tufan Aydogdu; Xiaoling Jin; Zongxiu Zhang; Rui Zhan; Leopold Puzis; Leonidas G. Koniaris; Teresa A. Zimmers

Cachexia, the metabolic dysregulation leading to sustained loss of muscle and adipose tissue, is a devastating complication of cancer and other chronic diseases. Interleukin-6 and related cytokines are associated with muscle wasting in clinical and experimental cachexia, although the mechanisms by which they might induce muscle wasting are unknown. One pathway activated strongly by IL-6 family ligands is the JAK/STAT3 pathway, the function of which has not been evaluated in regulation of skeletal muscle mass. Recently, we showed that skeletal muscle STAT3 phosphorylation, nuclear localization, and target gene expression are activated in C26 cancer cachexia, a model with high IL-6 family ligands. Here, we report that STAT3 activation is a common feature of muscle wasting, activated in muscle by IL-6 in vivo and in vitro and by different types of cancer and sterile sepsis. Moreover, STAT3 activation proved both necessary and sufficient for muscle wasting. In C(2)C(12) myotubes and in mouse muscle, mutant constitutively activated STAT3-induced muscle fiber atrophy and exacerbated wasting in cachexia. Conversely, inhibiting STAT3 pharmacologically with JAK or STAT3 inhibitors or genetically with dominant negative STAT3 and short hairpin STAT3 reduced muscle atrophy downstream of IL-6 or cancer. These results indicate that STAT3 is a primary mediator of muscle wasting in cancer cachexia and other conditions of high IL-6 family signaling. Thus STAT3 could represent a novel therapeutic target for the preservation of skeletal muscle in cachexia.


Hepatology | 2006

Paradoxical effects of short- and long-term interleukin-6 exposure on liver injury and repair

Xiaoling Jin; Teresa A. Zimmers; Eduardo A. Perez; Robert H. Pierce; Zongxiu Zhang; Leonidas G. Koniaris

Interleukin‐6 (IL‐6) is an important mediator of liver regeneration and repair that is also elevated in chronic liver diseases, including fatty liver of obesity and cirrhosis. IL‐6 has been reported both to delay and accelerate liver regeneration. We examined the effects on liver injury and regeneration of a continuous administration of exogenous IL‐6 to mice by injection of an IL‐6–expressing CHO‐cell line in athymic nude mice and by osmotic mini‐pump delivery of recombinant murine IL‐6. Short‐term IL‐6 administration (1‐2 days) accelerated early recovery of liver mass, whereas more long‐term administration (5‐7 days) markedly impaired liver regeneration. Similarly, short‐term IL‐6 treatment increased hepatic resistance to the lethal effects of the Fas agonist Jo‐2, but on more prolonged IL‐6 exposure the Jo‐2 resistance vanished. IL‐6 administration initially induced expression of the anti‐apoptotic proteins Bcl‐2 and Bcl‐xL, correlating with protection against Fas‐mediated cell death. More prolonged IL‐6 administration, however, resulted in marked induction of the pro‐apoptotic protein Bax. This result coincided with increased activation of the type II or intrinsic, mitochondrial path to cell death, manifested by increased caspase‐9 activation and increased cytochrome c release after Jo‐2 exposure. These data demonstrate that IL‐6 can function acutely to improve hepatic regeneration and repair, but that more chronic exposure not only abolishes the protective effects of IL‐6, but actually sensitizes the liver to injury and death. In conclusion, elevated IL‐6 in certain chronic liver diseases contributes to an increased likelihood of liver failure after injury. (HEPATOLOGY 2006;43:474–484.)


Journal of Bone and Joint Surgery, American Volume | 2009

Chondrosarcoma in the United States (1973 to 2003): An Analysis of 2890 Cases from the Seer Database

Angela Ylenia Giuffrida; Jorge E. Burgueno; Leonidas G. Koniaris; Juan C. Gutierrez; Robert Duncan; Sean P. Scully

BACKGROUND Current demographic, prognostic, and outcomes data on the diagnosis and treatment of chondrosarcoma have been based on case series reported by individual treatment centers. The SEER (Surveillance, Epidemiology and End Results) database is a validated national epidemiological surveillance system and cancer registry that has been used extensively to evaluate treatment outcomes in cases of malignancy. The purpose of the present study was to use this database to identify demographic and prognostic characteristics of chondrosarcoma and to describe the natural history following the treatment of this rare disease in the United States over the last thirty years. METHODS Two thousand eight hundred and ninety patients with chondrosarcoma were identified in the SEER database, and information regarding the demographic and clinical characteristics of the patients, the histological features and grade of the tumors, the location and size of the tumors, the surgical stage at the time of diagnosis, the use of surgery and radiation treatment, and survival were extracted. RESULTS Comparison of the overall and disease-specific survival rates revealed that patients who survived for ten years were more likely to die of events that were unrelated to chondrosarcoma. The disease-specific survival rate leveled off at ten years of follow-up. Univariate analysis revealed that female sex, a low histological grade, and local surgical stage were associated with a significant disease-specific survival benefit. An age of fifty years or less and an appendicular location of the tumor were associated with a significant overall survival benefit. On multivariate analysis, only grade and stage had significant association with disease-specific survival. On the basis of a comparison of survival rates according to the decade of diagnosis, it appears that there has been no significant improvement in survival over the last thirty years. CONCLUSIONS Only grade and stage are independent prognostic factors for survival in cases of chondrosarcoma. Current treatment algorithms have not improved the survival rates of patients with chondrosarcoma over the past thirty years. Routine patient surveillance following treatment should be extended to ten years of follow-up.


Shock | 2005

Growth differentiation factor-15/macrophage inhibitory cytokine-1 induction after kidney and lung injury.

Teresa A. Zimmers; Xiaoling Jin; Edward C. Hsiao; Sharon McGrath; Aurora F. Esquela; Leonidas G. Koniaris

The immunoregulatory cytokine macrophage inhibitory cytokine-1 (MIC-1), a divergent TGF-β family member, and its murine ortholog, growth/differentiation factor-15 (GDF-15) are induced in hepatocytes by surgical and chemical injury and heat shock. To better understand the in vivo role this factor plays in organ injury, we examined the regulation of GDF-15 in murine models of kidney and lung injury. We demonstrate herein induction of GDF-15/MIC-1 after surgical, toxic/genotoxic, ischemic, and hyperoxic kidney or lung injury. Gdf15 induction was independent of protein synthesis, a hallmark of immediate-early gene regulation. Although TNF induced GDF-15 expression, injury-elicited Gdf15 expression was not reduced in mice deficient for both TNF receptor subtype. Furthermore, although the stress sensor p53 is known to induce GDF-15/MIC-1 expression, injury-elicited Gdf15 expression was unchanged in p53-null mice. Our results demonstrate that GDF-15 induction after organ injury is a hallmark of many tissues. These data demonstrate that GDF-15/MIC-1 is an early mediator of the injury response in kidney and lung that might regulate inflammation, cell survival, proliferation, and apoptosis in a variety of injured tissues and disease processes.

Collaboration


Dive into the Leonidas G. Koniaris's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge