COMPARATIVE EFFECT OF INSULIN, GLIMEPIRIDE, AND METFORMIN ON INFLAMMATORY MARKERS IN TYPE 2 DIABETES MELLITUS

Insulin, glimepiride, and metformin prescribe as monotherapy or in combination to control glycemic state. The present study aimed to identify the anti-inflammatory activity of commonly used antidiabetic medications insulin, glimepiride, and metformin if any. A follow-up study of added metformin alone or with glimepiride to newly diagnosed diabetic patients and add metformin to patients treated with insulin or glimepiride monotherapy to establish the effect on the glycemic and inflammatory state. There are highly significant differences in glycemic and inflammatory markers when adding metformin to newly diagnosed diabetic patients and when combined with insulin or glimepiride monotherapy. Metformin is associated with high anti-inflammatory action in addition to improving glycemic and lipidomics states.

TMET-28. A METHOD FOR EX VIVO STABLE ISOTOPE TRACING IN SURGICALLY EXPLANTED GLIOMA ORGANOIDS

Stable isotope tracing is a powerful method for elucidating tumor metabolism. While in vivo stable isotope tracing is one of the most faithful approaches for studying metabolic activity under pathophysiologically relevant conditions, this method is technically challenging and costly to perform. We therefore sought to optimize an ex vivo stable isotope tracing approach under conditions that recapitulate the in vivo tumor microenvironment (TME), focusing on three key features: cellular heterogeneity, nutrient availability, and oxygenation. Surgically eXplanted Organoids (SXOs) are 3-dimensional glioma models that retain the diverse cell populations in human brain tumors. We tested whether glioma SXOs can be cultured in Human Plasma-Like Medium (HPLM) under brain-relevant oxygen levels (5%) for the purpose of stable isotope tracing. We cultured SXOs in conventional media, HPLM for 24 hours, or HPLM for 120 hours under 5% oxygen. We observed no significant differences in markers of tumor architecture, cellular proliferation rates, or stemness profiles. We then performed stable isotope tracing in SXOs cultured in HLPM at 5% oxygen. We acclimated SXOs to HPLM for 24 hours or 120 hours before replacing media with either HPLM (unlabeled) or HPLM with 15N2 glutamine (labeled). 15N isotopic labeling patterns in various metabolites were compared between the 24- and 120-hour conditions by linear regression. These patterns were strongly concordant over time (r2 = 0.9544), indicating that steady-state metabolic fluxes are stable in these cultures. We then analyzed intermediates that occupy key nodes in amino acid metabolism, redox homeostasis, and nucleotide synthesis pathways and found similarly strong concordance between labeling patterns at the individual metabolite level. Our findings outline an effective approach for conducting ex vivo stable isotope tracing in heterocellular glioma models under conditions that mimic the TME. This approach may complement and enhance analogous in vivo methods to provide new insights into glioma metabolism.

EGFR ligand shifts the role of EGFR from oncogene to tumour suppressor in EGFR-amplified glioblastoma by suppressing invasion through BIN3 upregulation

The epidermal growth factor receptor (EGFR) is a prime oncogene that is frequently amplified in glioblastomas. Here we demonstrate a new tumour-suppressive function of EGFR in EGFR-amplified glioblastomas regulated by EGFR ligands. Constitutive EGFR signalling promotes invasion via activation of a TAB1-TAK1-NF-κB-EMP1 pathway, resulting in large tumours and decreased survival in orthotopic models. Ligand-activated EGFR promotes proliferation and surprisingly suppresses invasion by upregulating BIN3, which inhibits a DOCK7-regulated Rho GTPase pathway, resulting in small hyperproliferating non-invasive tumours and improved survival. Data from The Cancer Genome Atlas reveal that in EGFR-amplified glioblastomas, a low level of EGFR ligands confers a worse prognosis, whereas a high level of EGFR ligands confers an improved prognosis. Thus, increased EGFR ligand levels shift the role of EGFR from oncogene to tumour suppressor in EGFR-amplified glioblastomas by suppressing invasion. The tumour-suppressive function of EGFR can be activated therapeutically using tofacitinib, which suppresses invasion by increasing EGFR ligand levels and upregulating BIN3.

Evaluate the safety and efficacy of dura sealant patch in reducing cerebrospinal fluid leakage following elective cranial surgery (ENCASE II): study protocol for a randomized, two-arm, multicenter trial

BACKGROUND

Cerebrospinal fluid (CSF) leakage is a frequent and challenging complication in neurosurgery, especially in the posterior fossa, with a prevalence of 8%. It is associated with substantial morbidity and increased healthcare costs. A novel dural sealant patch (LIQOSEAL) was developed for watertight dural closure. The objective of this study is to clinically assess the safety and effectiveness of LIQOSEAL as a means of reducing intra- as well as postoperative CSF leakage in patients undergoing elective posterior fossa intradural surgery with a dural closure procedure compared to the best currently available dural sealants.

METHODS

We will conduct a two-arm, randomized controlled, multicenter study with a 90-day follow-up. A total of 228 patients will be enrolled in 19 sites, of which 114 will receive LIQOSEAL and 114 an FDA-approved PEG sealant. The composite primary endpoint is defined as intraoperative CSF leakage at PEEP 20 cm H₂O, percutaneous CSF leakage within 90 days of, wound infection within 90 days of or pseudomeningocele of more than 20cc on MRI or requiring intervention. We hypothesize that the primary endpoint will not be reached by more than 10 patients (9%) in the investigational arm, which will demonstrate non-inferiority of LIQOSEAL compared to control.

DISCUSSION

This trial will evaluate whether LIQOSEAL is non-inferior to control as a means of reducing CSF leakage and safety TRIAL REGISTRATION: ClinicalTrials.gov NCT04086550 . Registered on 11 September 2019.

Antitumor Activity of a Mitochondrial-Targeted HSP90 Inhibitor in Gliomas

PURPOSE

To investigate the antitumor activity of a mitochondrial-localized HSP90 inhibitor, Gamitrinib, in multiple glioma models, and to elucidate the antitumor mechanisms of Gamitrinib in gliomas.

EXPERIMENTAL DESIGN

A broad panel of primary and temozolomide (TMZ)-resistant human glioma cell lines were screened by cell viability assays, flow cytometry, and crystal violet assays to investigate the therapeutic efficacy of Gamitrinib. Seahorse assays were used to measure the mitochondrial respiration of glioma cells. Integrated analyses of RNA sequencing (RNAseq) and reverse phase protein array (RPPA) data were performed to reveal the potential antitumor mechanisms of Gamitrinib. Neurospheres, patient-derived organoids (PDO), cell line-derived xenografts (CDX), and patient-derived xenografts (PDX) models were generated to further evaluate the therapeutic efficacy of Gamitrinib.

RESULTS

Gamitrinib inhibited cell proliferation and induced cell apoptosis and death in 17 primary glioma cell lines, 6 TMZ-resistant glioma cell lines, 4 neurospheres, and 3 PDOs. Importantly, Gamitrinib significantly delayed the tumor growth and improved survival of mice in both CDX and PDX models in which tumors were either subcutaneously or intracranially implanted. Integrated computational analyses of RNAseq and RPPA data revealed that Gamitrinib exhibited its antitumor activity via (i) suppressing mitochondrial biogenesis, OXPHOS, and cell-cycle progression and (ii) activating the energy-sensing AMP-activated kinase, DNA damage, and stress response.

CONCLUSIONS

These preclinical findings established the therapeutic role of Gamitrinib in gliomas and revealed the inhibition of mitochondrial biogenesis and tumor bioenergetics as the primary antitumor mechanisms in gliomas.

A Modified Nucleoside 6-Thio-2'-Deoxyguanosine Exhibits Antitumor Activity in Gliomas

PURPOSE

To investigate the therapeutic role of a novel telomere-directed inhibitor, 6-thio-2'-deoxyguanosine (THIO) in gliomas both in vitro and in vivo.

EXPERIMENTAL DESIGN

A panel of human and mouse glioma cell lines was used to test therapeutic efficacy of THIO using cell viability assays, flow cytometric analyses, and immunofluorescence. Integrated analyses of RNA sequencing and reverse-phase protein array data revealed the potential antitumor mechanisms of THIO. Four patient-derived xenografts (PDX), two patient-derived organoids (PDO), and two xenografts of human glioma cell lines were used to further investigate the therapeutic efficacy of THIO.

RESULTS

THIO was effective in the majority of human and mouse glioma cell lines with no obvious toxicity against normal astrocytes. THIO as a monotherapy demonstrated efficacy in three glioma cell lines that had acquired resistance to temozolomide. In addition, THIO showed efficacy in four human glioma cell lines grown as neurospheres by inducing apoptotic cell death. Mechanistically, THIO induced telomeric DNA damage not only in glioma cell lines but also in PDX tumor specimens. Integrated computational analyses of transcriptomic and proteomic data indicated that THIO significantly inhibited cell invasion, stem cell, and proliferation pathways while triggering DNA damage and apoptosis. Importantly, THIO significantly decreased tumor proliferation in two PDO models and reduced the tumor size of a glioblastoma xenograft and a PDX model.

CONCLUSIONS

The current study established the therapeutic role of THIO in primary and recurrent gliomas and revealed the acute induction of telomeric DNA damage as a primary antitumor mechanism of THIO in gliomas.

TMOD-06. CREATION OF PATIENT-DERIVED LOWER GRADE GLIOMA ORGANOID MODELS FOR PERSONALIZED TREATMENT RESPONSE ASSESSMENT

Creating in vitro models of lower grade glioma represents a major challenge in neuro-oncology research. There are few such models that are tractable and widely used, which has hindered understanding of the biology of these tumors. Recently, substantial progress has been made in generating patient-derived in vitro organoid models of high grade glioma, but modeling lower grade disease remains difficult. Based on our experience creating neurosphere cultures of lower grade astrocytomas from genetically engineered mice, we hypothesized that modifying patient-derived organoid generation protocols to incorporate physiological oxygen levels would allow establishment and propagation of lower grade glioma organoids. In this study, we show that this approach supports efficient organoid model generation from primary glioma specimens across all histological subtypes and tumor grades (WHO Grade I-IV, n = 20). These organoid models retain key characteristics of their respective parental tumors, including IDH mutations and other genetic alterations, metabolite profiles, intratumoral heterogeneity, cellular composition, and cytoarchitectural features. Importantly, lower grade glioma organoids can be cultured for months and reanimated after biobanking. Our high success rate ( >90%) in establishing organoid models from primary lower grade glioma tissue samples further highlighted opportunities for treatment response assessments. To perform longitudinal measurements of therapy-induced changes in glioma organoid viability, we designed a novel, non-invasive imaging assay (termed rapid apex imaging) to determine real-time treatment response in low and high grade gliomas. We evaluated longitudinal responses of glioblastoma and IDH1 R132H-positive Grade II astrocytoma organoids to temozolomide and olaparib with and without radiation treatment. We quantified topological changes in organoid structure by building a bioinformatics tool to translate imaging data into a cellularity metric as a biomarker of organoid response. Our work unveils an effective new method to create in vitro, personalized models of lower grade glioma that supports elucidation of treatment sensitivity profiles.

Multiparametric MRI assessment of response to convection-enhanced intratumoral delivery of MDNA55, an interleukin-4 receptor targeted immunotherapy, for recurrent glioblastoma

Background

Glioblastoma (GBM) is the most common malignant brain tumor and carries a dismal prognosis. Attempts to develop biologically targeted therapies are challenging as the blood-brain barrier can limit drugs from reaching their target when administered through conventional (intravenous or oral) routes. Furthermore, systemic toxicity of drugs often limits their therapeutic potential. To circumvent these problems, convection-enhanced delivery (CED) provides direct, targeted, intralesional therapy with a secondary objective to alter the tumor microenvironment from an immunologically "cold" (nonresponsive) to an "inflamed" (immunoresponsive) tumor.

Case Description

We report a patient with right occipital recurrent GBM harboring poor prognostic genotypes who was treated with MRI-guided CED of a fusion protein MDNA55 (a targeted toxin directed toward the interleukin-4 receptor). The patient underwent serial anatomical, diffusion, and perfusion MRI scans before initiation of targeted therapy and at 1, 3-month posttherapy. Increased mean diffusivity along with decreased fractional anisotropy and maximum relative cerebral blood volume was noted at follow-up periods relative to baseline.

Conclusion

Our findings suggest that diffusion and perfusion MRI techniques may be useful in evaluating early response to CED of MDNA55 in recurrent GBM patients.

Synergistic immunotherapy of glioblastoma by dual targeting of IL-6 and CD40

Immunologically-cold tumors including glioblastoma (GBM) are refractory to checkpoint blockade therapy, largely due to extensive infiltration of immunosuppressive macrophages (Mϕs). Consistent with a pro-tumor role of IL-6 in alternative Mϕs polarization, we here show that targeting IL-6 by genetic ablation or pharmacological inhibition moderately improves T-cell infiltration into GBM and enhances mouse survival; however, IL-6 inhibition does not synergize PD-1 and CTLA-4 checkpoint blockade. Interestingly, anti-IL-6 therapy reduces CD40 expression in GBM-associated Mϕs. We identify a Stat3/HIF-1α-mediated axis, through which IL-6 executes an anti-tumor role to induce CD40 expression in Mϕs. Combination of IL-6 inhibition with CD40 stimulation reverses Mϕ-mediated tumor immunosuppression, sensitizes tumors to checkpoint blockade, and extends animal survival in two syngeneic GBM models, particularly inducing complete regression of GL261 tumors after checkpoint blockade. Thus, antibody cocktail-based immunotherapy that combines checkpoint blockade with dual-targeting of IL-6 and CD40 may offer exciting opportunities for GBM and other solid tumors.

A Quantitative Analysis of Social Media to Determine Trends in Brain Tumor Care and Treatment

Background

Approximately 80,000 primary brain tumors are diagnosed annually. Social media provides a source of information and support for patients diagnosed with brain tumors; however, use of this forum for dissemination of information about brain tumors has not been evaluated. The objective of this study was to evaluate social media utilization and content related to brain tumors with an emphasis on patients’ trends in usage.

Methods

Social media platforms were systematically evaluated using two search methods: systematic manual inquiry and a keyword-based social media tracker. The search terms included brain tumor, glioblastoma, glioma, and glioblastoma multiforme. Social media content (which includes Facebook pages and groups, YouTube videos, and Twitter or Instagram accounts) and posts were assessed for activity (as quantified by views of posts) and analyzed using a categorization framework.

Results

The manual and keyword searches identified 946 sources of social media content, with a total count of 7,184,846 points of engagement. Social media platforms had significant variations in content type. YouTube was the largest social media platform for sharing content related to brain tumors overall, with an emphasis on surgical videos and documented patient experiences. Facebook accounted for the majority of patient-to-patient support, and Twitter was the most common platform for scientific dissemination. Overall social media content was mostly focused on treatment overviews and patient experience. When evaluated by search term, most social media posts by the “brain tumor” community shared illness narratives, and searches specific to “glioma” and “glioblastoma” demonstrated a higher proportion of educational and treatment posts.

Conclusions

This study presents novel observations of the characteristics of social media utilization for the online brain tumor community. A robust patient community exists online, with an emphasis on sharing personal narratives, treatment information, patient-to-patient support, treatment options, and fundraising events. This study provides a window to the role of social media utilization by patients, their families, and health professionals. These findings demonstrate the different roles of Facebook, YouTube, and Twitter in the rapidly changing era of social media and its relationship with neurosurgery and neuro-oncology.

TMOD-14. CREATION OF A GENETICALLY ENGINEERED MOUSE MODEL OF ANAPLASTIC ASTROCYTOMA DRIVEN BY THE IDH1-R132H ONCOGENE

Despite the high prevalence of IDH1-R132H mutations in lower grade gliomas, the ability to study this mutation in vivo has been hampered by a lack of faithful mouse models. Therefore, we used a CRISPR/Cas9- and AAV-based strategy to create a genetically engineered mouse model (GEMM) of astrocytoma driven by IDH1-R132H that recreates the genetic landscape of human IDH1 mutant astrocytoma. IDH1 mutations in astrocytomas often co-occur with mutations in TP53, ATRX, and either PIK3R1 or PIK3CA. Using human astrocytes immortalized via expression of telomerase (which phenocopies ATRX loss) and HPV E6 and E7 oncoproteins (which phenocopy p53 and pRb loss, respectively), we found that PIK3R1 and IDH1 oncogenes cooperate to promote anchorage-independent cell growth in vitro and orthotopic brain tumor formation in vivo. These data identified a combination of clinically relevant mutations that we hypothesized could be leveraged to cause spontaneous astrocytoma formation in mice. To simultaneously engineer Idh1, Pik3ca, Tp53, and Atrx mutations in mouse brain tissue, we intracranially injected adeno-associated virus (AAV) expressing Cre recombinase and sgRNAs targeting murine Atrx and Tp53 genes into four mouse strains with the following conditional alleles: 1) LSL-Cas9; 2) LSL-Cas9; LSL-Pik3caH1047R, 3) LSL-Cas9; LSL-Idh1R132H, and 4) LSL-Cas9; LSL-Idh1R132H; LSL-Pik3caH1047R. Grade III anaplastic astrocytomas preferentially formed 9-14 months after injecting the mice carrying both the Idh1 and Pik3ca conditional alleles. These astrocytomas harbored all intended mutations, expressed astrocytoma lineage markers, and displayed elevated (R)-2-hydroxyglutarate, the oncometabolite produced by mutant Idh1. To create an additional model with shorter tumor latency, we transplanted glioma stem-like cells derived from our GEMM into recipient mice to produce Idh1 mutant astrocytoma allografts. These allografts provide a tractable platform for preclinical therapeutic studies. Taken together, our findings show that IDH1 and PI3K oncoproteins cooperate to promote gliomagenesis and unveil new genetically faithful mouse models of mutant IDH1-driven astrocytoma.

Relationship of the Optic Nerve to the Medial Rectus Muscle During Endonasal Dissection of the Medial Intraconal Orbital Apex

BACKGROUND

Few studies have established surgical landmarks for endoscopic endonasal dissection of the intraconal orbital apex (OA).

OBJECTIVE

We describe the optic nerve (ON) anatomy and its relationships, as seen during a fully endoscopic, endonasal approach to the medial intraconal OA.

METHODS

The study question was approached through a cadaver dissection and a radiographic study. Four formalin-fixed, latex-injected cadaver heads were dissected using transnasal endoscopic techniques. Dissection was performed using 0 degree and 30 degree nasal endoscopes and standard endoscopic sinus surgical instrumentation. A bi-nostril 4-handed technique was used. The anatomy of 8 medial OAs was evaluated and recorded. As the radiographic portion, 100 consecutively enrolled patient magnetic resonance images were evaluated, with particular attention given to the relationship of the ON to the medial rectus muscle (MRM) in 200 orbits.

RESULTS

Intraconally, the ON consistently coursed along the superior half of the MRM. Interestingly, the nerve was more easily identified from a superior approach after retracting the MRM inferiorly. With the identification of the nerve at the OA, carrying the dissection of the medial OA was easily accomplished with the ON as the guiding landmark. The radiographic portion of this study revealed a consistent relationship between the superior edge of the ON and the MRM. This relationship was maintained in the orbital apex in 98.4%-100% of the orbits examined.

CONCLUSION

The superior edge of the optic nerve is consistently found coursing along the superior half of the MRM, facilitating facile identification and further dissection navigation.

The concurrent and longitudinal associations of temperament and nutritional risk factors in early childhood

BACKGROUND

Early childhood temperament is increasingly recognized as an important attribute that may impact screen time use, outdoor play and childhood obesity. The relationship between temperament and nutrition in preschool children is less clear.

OBJECTIVE

The objective of the study is to investigate if temperament dimensions (negative affectivity, effortful control and surgency) in early childhood are associated with nutritional risk factors.

METHODS

Six hundred seventy-eight children were followed (mean age at baseline visit 3.1 years; mean time to follow-up 16.5 months). Parents reported on child temperament and nutritional risk factors during regularly scheduled well-child clinic visits.

RESULTS

A mixed effect model demonstrated a significant association between higher negative affectivity (1.03; 95% CI 0.69 to 1.37) and higher effortful control (-0.88; 95% CI -1.27 to -0.49) on concurrent nutritional risk, independent of covariates. Multivariate linear regression analysis identified that higher effortful control, and not negative affectivity, was significantly associated with a decrease in nutritional risk (-0.67; 95% CI -1.10 to -0.24) over time, independent of covariates. There was no relationship identified between surgency and nutritional risk.

CONCLUSION

Three-year-old children with higher effortful control had reduced nutritional risk at 5 years of age. Future nutritional risk prevention strategies may benefit from interventions to increase effortful control in early childhood.

How could improvement in the management of T-cell acute lymphoblastic leukemia be achieved? Experience of Princess Nourah Oncology Center, National Guard Hospital, Jeddah, Saudi Arabia

10048

Background: T-cell acute lymphoblastic leukemia (T-ALL) is representing 10–15% of pediatric ALL. The use of more intensive treatments and risk adapted therapy have significantly improved the outcome of patients with T-ALL and event-free survival rate of 60–70% are now reported in children. Our published data showed that T-ALL phenotype patients fared poorly with 5 year survival of 27% versus 83% for precursor B-ALL (Recent Advances Research Update: 2006, 7; 1, P 51–56). Objectives: We reviewed all patients diagnosed with T-ALL to assess risk classification according to NCI criteria, type of therapy received, overall survival and causes of mortality. Methods: Retrospective review of all patients files diagnosed with T-ALL from 1989 until now with data collection including; sex, age, white cell count (WBCs), CNS disease, type of protocol used, length of survival, overall survival, cause of death (toxic, disease). Results: Over the last 20 years, T-ALL cases registered were 52/460 (11%) of all ALL cases, Male:Female ratio 42:10 (4.2:1), median age 7 year (range: 1.5–12 yrs). Median WBCs 50,000/Cmm (range: 1.500–619,000/Cmm) and positive CNS at diagnosis 10/52 (20%). NCI risk classification criteria showed SR 24/52 (46%) and HR 28/52 (54%). Protocols used were UKALL ( n = 21; 3 UKALL X-B, 4 UKALL X-D, 10 UKALL XI and 4 MRC-97 ). BFM (n = 8); and CCG 1961 (n = 23). Overall survival 27/52 (52%) and 25 pts. died (48%); 15 secondary to disease recurrence (9 on UKALL, 4 BFM, 2 CCG 1961); 4 during induction, 1 fulminant hepatic failure, 1 tumor lysis syndrome, and 4 due to toxicities (mucormycosis, staphylococcal toxic shock syndrome, CMV pneumonia, pseudomonas sepsis). Survival for different regimen; UKALL: 5/21=31%, BFM: 4/8=50%, CCG: 18/23=78%, while overall cohort survival 52%. Mean length of survivors 4 year (range 4–140 month) and mean length for non-survivors 1 year (range 0.1–40 months). Conclusions: This review showed the improvement of T-ALL survival from 27% to 56%. Using augmented therapy based on CCG1961 was associated with better outcome. Further risk and response stratification in addition to intensification of therapy for T-cell ALL in our center may prove to be beneficial. Therapy remains an important prognostic factor.

No significant financial relationships to disclose.

Twenty cases of adult-to-adult living-related liver transplantation: single-center experience in Saudi Arabia

BACKGROUND

The deceased donor organ shortage has forced surgeons to implement innovations, including living-related liver transplantation (LRLT).

OBJECTIVE

To present the first 20 cases of adult LRLT in a single center in Saudi Arabia.

METHODS

From November 2000 to May 2004, we performed 20 cases of LRLT. Eighteen donors were men and 2 were women. Their median age was 27 years. Seventeen of the recipients were men and 3 were women of median age 55 years. One patient received combined liver and kidney grafts.

RESULTS

All cases had liver cirrhosis. Seven had hepatitis C; six, hepatitis B and C; three, hepatitis B; one, alcoholic cirrhosis; one, Bylar disease, one hepatic schistosomiasis, and one cryptogenic cirrhosis. Three cases had associated hepatocellular carcinomas. There was no donor mortality. In the recipients, the overall patient and graft survival was 85%. While 10 donors presented uneventful postoperative courses, 8 experienced minor complications and 2, major complications: biliary stricture and portal vein thrombosis. Recipients complications included biliary complications (35%), acute rejection (20%), hepatitis C reactivation (20%), hepatic vein stenosis (10%), hepatic artery stenosis (5%), and hepatocellular carcinoma recurrence (5%).

CONCLUSIONS

LRLT has become a standard option in adults with end-stage liver failure in our center.

Incidence and management of biliary complications after orthotopic liver transplantation: ten years' experience at King Fahad National Guard Hospital

BACKGROUND

Despite technical modifications and application of various surgical techniques, biliary tract complications remain a major source of morbidity after orthotopic liver transplantation. We sought to assess the incidence and management of biliary complications at a single liver transplant unit.

METHODS

Among 184 consecutive deceased donor liver transplants performed between February 1994 and July 2004, 66 were female patients and 118 male patients of age range 2(1/2) to 69 years. We retrospectively reviewed the data regarding biliary complications in liver transplant recipients, after 115 duct-to-duct anastomoses and 65 hepaticojejunostomy. We analyzed the incidence and type of biliary complications, management sequence, and success rate. We analyzed the correlation between the modality of biliary reconstruction and the type/incidence of biliary complications.

RESULTS

Thirty-two patients developed biliary complications, giving an overall incidence of 17.4%. There was a higher incidence of complications among patients in the hepaticojejunostomy group (21.5%) than the duct-to-duct technique (15.1%). Bile leakage occurred in 12 patients, including eight successful cases (66.6%) of endoscopic stent insertion/radiological techniques and surgery in four cases (33.3%). Among the 12 patients with initial leaks, six developed a subsequent stricture (50%). There were 26 cases of biliary stricture, including 22 (84.6%) who were initially managed using nonsurgical techniques with a success rate of 59%.

CONCLUSION

Biliary complications remain an important cause of morbidity after orthotopic liver transplantation. They can usually be managed percutaneously or endoscopically; however, tight strictures and major leaks frequently required surgical intervention.

Neutrophils and lymphoid chimerism after adult living-related liver transplantation from a homozygous donor

Chimerism and graft-versus-host disease (GVHD) pose significant risks to liver transplant patients. The risk of chimerism and GVHD is higher among cases of living-related liver transplant (LRLT). Donors homozygous at all HLA loci carry a higher risk for GVHD. Herein we present a case of LRLT. The recipient suffered from end-stage liver disease and received a right lobe graft from his son. After 8 months posttransplant, the patient developed profound bone marrow depression. The patient was negative for CMV, Brucella, HHV6, HHV8, HBV, HCV, and parvovirus. No skin or GI signs of GVHD were noted. The patient and donor were HLA typed by SSP. The donor was homozygous for all HLA loci while the patient shared the class II homozygosity and was class I heterozygous. Chimerism studies were prompted after noting that the neutrophil compartment of the patient was homozygous for all HLA loci. This initiated further studies of the PMN and lymphocytes by microsatellite analysis. A total 15 microsatellites were analyzed. The results suggest that the majority (75%) of the PMNs and 45% of the lymphocytes were of donor origin. The patient was treated with G-CSF; his WBC counts returned to normal. At 2.5 years posttransplant the patient had not developed GVHD, despite the large number of donor lymphocytes circulating in his bloodstream. The only complaint he had was severe arthritis, which was treated with steroids. It must be investigated whether this was the result of GVHD.

Imaging patients with "post-cholecystectomy syndrome": an algorithmic approach

AIM

To assess the role of ultrasound (US), magnetic resonance cholangiopancreatography (MRCP) and liver function tests (LFTs) in the evaluation of selected patients presenting with late post-cholecystectomy syndrome (PCS) who were referred for endoscopic retrograde cholangiopancreatography (ERCP).

MATERIALS AND METHODS

In a retrospective study a final group of 42 patients with PCS referred for diagnostic ERCP underwent MRCP and abdominal US. ERCP and MRCP images were assessed for bile duct diameters and the presence of strictures and stones. A common bile duct (CBD) diameter of < 10mm was considered normal, whereas > or = 10mm was considered abnormal on US. Findings were correlated to LFTs with contingency table results performed for single techniques and combination of methods.

RESULTS

In total 14 stones and one stricture were seen. US had a high negative predictive value (86.4%). MRCP had a sensitivity of 100% and specificity of 88.0%. ERCP is the most accurate test but failed in 11 patients, five of whom had a stone. The accuracy of US and LFTs increases to 93.8% if test results agree in either negative or positive outcome.

CONCLUSION

US and LFTs are first-line tests in PCS. If the CBD on US is > or = 10mm, but no cause is identified, MRCP should be performed. If US and LFTs are normal then MRCP is not necessary. The availability of LFTs raises the diagnostic value of imaging.

Comparison of the effects of nitric oxide synthase, guanylate cyclase and potassium channel inhibition on vascular contractions in vitro in the rat

1. We have investigated the differences between the nitric oxide synthase inhibitor L-NMMA, the guanylate cyclase inhibitor methylene blue and the potassium channel blockers apamin and charybdotoxin or apamin and iberiotoxin, in their abilities to increase vasoconstrictor responses in rat small mesenteric arterial rings. 2. When administered during the maintained contraction to PGF2alpha (10 microM), L-NMMA (100 microM) or the combination of apamin (0.7 microM) and charybdotoxin (0.1 microM) significantly increased the contractile response. Methylene blue (10 microM) increased the contraction, but this did not reach significance. However, apamin (0.7 microM) and iberiotoxin (0.1 microM) also significantly increased the contractile response. 3. The combination of L-NMMA or methylene blue with apamin/charybdotoxin produced significantly greater increases in the contractile response to PGF2alpha than achieved individually. 4. Relaxations to acetylcholine (10 microM) were significantly reduced by L-NMMA or methylene blue but not by apamin in combination with charybdotoxin or iberiotoxin. 5. Since apamin/iberiotoxin had similar effects to apamin/charybdotoxin, it is likely that the actions of these agents involve direct actions on smooth muscle potassium channels rather than inhibition of endothelium-derived hyperpolarising factor (EDHF). These results suggest that endothelium-derived nitric oxide but not EDHF has a major role in modulating vascular tone under these conditions.

Comparison of the effects of nitric oxide synthase inhibition and guanylate cyclase inhibition on vascular contraction in vitro and in vivo in the rat

We have investigated the differences between the nitric oxide synthase inhibitor (NOSI), L-NMMA, and the guanylate cyclase inhibitors (GCI), methylene blue and LY 83583, in their abilities to increase vasoconstrictor responses in vitro and in vivo. In rat small mesenteric arterial rings, 1 h exposure to the NOSI, L-NMMA (100 microM), and the GCI, methylene blue (10 microM), alone or in combination with L-NMMA, caused a significant reduction in the maximum relaxation to ACh in mesenteric arteries pre-contracted with the thromboxane mimetic U46619 (10 microM). Hence, both NOSI and GCI inhibit endothelium-dependent relaxations to ACh in rat small mesenteric artery. However, 1 h exposure to L-NMMA and L-NNA (both 100 microM), but not methylene blue (10 microM), significantly increased the contractile response to U-46619 (10 microM) in rat small mesenteric artery. It was decided to investigate further this difference between NOSI and methylene blue. In rat small mesenteric arterial rings, L-NMMA (10 microM) and LY 83583 (1-10 microM) significantly increased the contractile response to KCl (40 mM) or to noradrenaline (10 microM), when administered during the contraction. However, methylene blue (1-10 microM) increased the contractile response to KCl but not noradrenaline. In rat aortic rings, L-NMMA (100 microM), methylene blue (1-10 microM) and LY 83583 (1-10 microM) significantly increased the contractile response to KCl (40 mM) or to noradrenaline (1 microM). In the pithed rat preparation, L-NMMA (40.3 micromol kg(-1), i.v.) significantly increased the pressor response both to bolus injection of noradrenaline (3.13 nmol kg[-1]) and to spinal pressor nerve stimulation. However, methylene blue (3.13-15.6 micromol kg[-1]) or LY 83583 (4.0-40.0 micromol kg[-1]), failed to affect pressor responses to either NA or pressor nerve stimulation. Hence, there are differences between NOSI and GCI in their abilities to increase vasoconstrictor responses, especially when comparing responses in vitro and in vivo. This suggests that nitric oxide has actions in addition to activation of guanylate cyclase to modulate vasoconstrictor responses, presumably by membrane hyperpolarisation, and that this action may be more important in vivo.

Functional identification of the active-site nucleophile of the human 85-kDa cytosolic phospholipase A2

Ser-228 has been shown to be essential for the catalytic activity of the human cytosolic phospholipase A2 (cPLA2). However, its involvement in catalysis has not yet been demonstrated. Using site-directed mutagenesis, active-site directed irreversible inhibitors, and the novel fluorogenic substrate 7-hydroxycoumarinyl gamma-linolenate, evidence is presented to show that the hydroxyl group of Ser-228 is the catalytic nucleophile of cPLA2. Replacement of Ser-228 by Ala, Cys, or Thr resulted in the inability of these mutants to mediate calcium ionophore induced PGE2 production in COS-7 cells cotransfected with the cPLA2 mutants and cyclooxygenase-1. Cell lysates from these transfected cells also had undetectable levels of cPLA2 phospholipid hydrolyase activity as did the affinity column purified S228A and S228C cPLA2 mutants overexpressed in insect cells. The loss in activity was not due to the inability of the mutant enzymes to translocate to the substrate lipid interface since the purified S228C cPLA2 mutant, like the wild type, translocated to the phospholipid membrane in the presence of calcium as judged by fluorescence energy transfer. However, when an activated substrate, 7-hydroxycoumarinyl gamma-linolenate (pKa approximately 7.8 for its leaving group) was used as substrate, there was a significant level of 7-hydroxycoumarin esterase (7-HCEase) activity (about 1% of wild type) associated with the purified S228CC cPLA2 mutant. The S228A cPLA2 mutant was catalytically inactive. Contrary to wild type cPLA2, the 7-HCEase activity of the thio-cPLA2 was not titrated by the irreversible active-site-directed inhibitor methyl arachidonyl fluorophosphonate, but rather titrated by one equivalent of arachidonyl bromomethyl ketone, an arachidonyl binding site directed sulfhydryl reagent. These results are compatible with the hydroxyl of Ser-228 being the catalytic nucleophile of cPLA2 and that cysteine can replace serine as the nucleophile, resulting ina thiol-cPLA2 with significantly reduced catalytic power.

Human cytosolic phospholipase A2 expressed in insect cells is extensively phosphorylated on Ser-505

Cytosolic PLA2 (cPLA2) has been implicated in the release of the arachidonic acid utilized in the inflammatory cascade. Phosphorylation of cPLA2 on Ser-505 by MAP kinase in response to agonist treatment, is thought to be one of the mechanisms required for activation of the enzyme in the cell. In order to obtain enough material for enzymological studies as well as to investigate the role of phosphorylation in the activation of cPLA2, the human enzyme was overexpressed in insect cells using a recombinant baculovirus. We report here on the characterization of the phosphorylation state of cPLA2 overexpressed in Sf9 cells. The level of overexpressed cPLA2 was shown to peak between 48 and 60 h post-infection, by this time the phosphorylated enzyme could easily be detected because of its reduced mobility on polyacrylamide gels. The reduced mobility or gel-shift has been shown to be due to phosphorylation of Ser-505. To determine whether this was also the case for insect cell overexpressed cPLA2, Ser-505 was replaced by Ala, and this mutant (cPLA2S505A) was expressed in Sf9 cells. Analysis of the overexpressed cPLA2S505A showed that it migrated only as the lower unshifted cPLA2 band confirming that the baculovirus overexpressed cPLA2 is extensively phosphorylated on Ser-505. Furthermore, treatment of infected Sf9 cells expressing the wild-type cPLA2 with phorbol 12-tetradecanoate 13-acetate (TPA) shifted all of the overexpressed cPLA2 to the phosphorylated Ser-505 form. When infected Sf9 cells were labelled with [32P], in addition to labelling of Ser-505 other sites were also labelled. Both cPLA2 and cPLA2S505A were purified from infected Sf9 cells and the specific activity for each of the enzymes was measured in a phosphatidylcholine vesicle fluorescence assay using 1-(10-pyrenedecanyl)arachidonyl-sn-glycero-3-phosphocholine as substrate. Under these conditions the specific activity of cPLA2 was, 2 mumol/min per mg, whereas cPLA2S505A was 7-fold less active. These findings suggest that Sf9 cells have a mechanism for phosphorylating cPLA2 similar to that found in mammalian cells which probably proceeds through a MAP kinase. Thus, insect cell overexpressed cPLA2 is a very good source for the Ser-505 phosphorylated enzyme.

Effect of thermal injury and sepsis on neutrophil function

Burn injury and sepsis have been repeatedly demonstrated to impair the function of circulating (blood) neutrophils. As a result of the difficulty in harvesting and purifying neutrophils from the burn wound, there have been minimal investigations to date on the effect of burn injury and sepsis on the function of neutrophils which have reached the wound. We utilized a sponge matrix model in order to obtain neutrophils from burned and burned-infected rats. Despite having a higher concentration of neutrophils in the blood, both the burned and burned-infected rats were noted to have a decreased number of neutrophils infiltrating the sponge compared with the controls (1.91 +/- 0.30 x 10(6), 2.31 +/- 0.47 x 10(6), and 4.82 +/- 0.64 x 10(6) neutrophils per sponge, respectively). Blood neutrophils from both the burned and burned-infected rats had a greater chemiluminescence capacity than neutrophils from the control group (p < 0.0001). This enhanced capacity was not present with sponge neutrophils obtained from the burned-infected group. The diminished capacity may have been the result of a decreased concentration of prostaglandin E in the sponge fluid of the burned-infected rats compared with that of the burned or control rats (52 +/- 9, 135 +/- 15, and 114 +/- 13 pg/mL of sponge fluid, respectively).