Novel method for determining when a field-collected donor unit is sufficiently full

BACKGROUND

Whole blood (WB) collections can occur downrange for immediate administration. An important aspect of these collections is determining when the unit is sufficiently full. This project tested a novel method for determining when a field collection is complete.

METHODS

The amount of empty space at the top of WB units, destined to become LTOWB or separated into components, that were collected at blood centers or hospitals was measured by holding a WB unit off the ground and placing the top of a piece of string where the donor tubing entered the bag. The string was marked where it intersected the top of the column of blood in the bag and measured from the top. The WB units were also weighed.

RESULTS

A total of 15 different bags, two of which were measured in two different filling volumes, from 15 hospitals or blood centers were measured and weighed. The most commonly used blood bag, Terumo Imuflex SP, had a median string length of 9 mm (range: 2-24 mm) and weighed a median of 565.1 g (range: 524.8-636.7 g).

CONCLUSION

Pieces of string can be precut to the appropriate length depending on the type of bag before a mission where field WB collections might be required and a mark placed on the bag before the collection commences to indicate when the unit is full.

Soluble RAGE Prevents Type 1 Diabetes Expanding Functional Regulatory T Cells

Type 1 diabetes is an autoimmune disease with no cure, where clinical translation of promising therapeutics has been hampered by the reproducibility crisis. Here, short-term administration of an antagonist to the receptor for advanced glycation end products (sRAGE) protected against murine diabetes at two independent research centers. Treatment with sRAGE increased regulatory T cells (Tregs) within the islets, pancreatic lymph nodes, and spleen, increasing islet insulin expression and function. Diabetes protection was abrogated by Treg depletion and shown to be dependent on antagonizing RAGE with use of knockout mice. Human Tregs treated with a RAGE ligand downregulated genes for suppression, migration, and Treg homeostasis (FOXP3, IL7R, TIGIT, JAK1, STAT3, STAT5b, CCR4). Loss of suppressive function was reversed by sRAGE, where Tregs increased proliferation and suppressed conventional T-cell division, confirming that sRAGE expands functional human Tregs. These results highlight sRAGE as an attractive treatment to prevent diabetes, showing efficacy and reproducibility at multiple research centers and in human T cells.

Abstract 5710: Identification of convergent gene repression mechanisms through integrative genomic and DNA methylation analysis in TRACERx

Introduction: Lung TRACERx is a prominent study employing multi-region and longitudinal multi-omics sequencing to unravel the evolutionary trajectories of lung cancer. Aberrant DNA methylation patterns have been widely described in nearly all human cancers, yet their interplay with DNA mutations in lung cancer is not well understood. Incorporating the contribution of epigenetic modifications to cancer evolution trajectories within TRACERx could improve our understanding of the intricate relationship between genetic and epigenetic changes in non-small cell lung cancer (NSCLC) evolution.

Methods: Multi-region sampling from 38 TRACERx patients including 112 tumor regions and 37 matched normal adjacent tissue samples was performed. Reduced representation bisulfite sequencing (RRBS) was performed to assess DNA methylation and the CAMDAC (Larose-Cadieux et al, 2020) was applied to estimate purified tumor methylation rates and correct for copy number changes. Whole exome sequencing and somatic copy number alterations (SCNAs) were inferred using the ASCAT tool (Van Loo et al, 2010) and Methsig (Pan et al, 2021) was performed to discover new methylation driver genes.

Results: Using multi-region sequencing, we identified ubiquitous hypermethylation of 29 known driver genes in both lung adenocarcinoma (LUAD) and squamous cell lung cancer (LUSC), together with an additional 9 and 27 genes exclusive to LUSC and LUAD, respectively. We also identified 13 and 7 driver genes non-ubiquitously hypermethylated exclusively in LUSC and LUAD, respectively. Using a differential methylation based approach, we describe a method to determine the extent of intra-tumor methylation heterogeneity akin to established ITH scores based on genomics data. In addition, we report the identification of novel subtype-specific methylation driver genes enriched in HOX family members which are related to cancer progression. Through integration of DNA methylation and genomic sequencing data, we identify parallel mechanisms contributing towards ubiquitous tumor suppressor gene alterations. At the patient level, multiple driver genes such as NSD1, GATA3 and MGA were subject to repression by both copy number loss and DNA hypermethylation. Finally, we describe dosage-compensation of genes such as the Notch ligands JAG2 and DLK1 that are proximal to amplified oncogenes and hypermethylated during tumor evolution.

Conclusion: We describe the contribution of DNA methylation and genomic alterations to altering the landscape of NSCLC. Leveraging DNA methylation, we can determine the extent of convergent repression mechanisms in different regions of the same tumor, assess DNA methylation heterogeneity, and discover DNA methylation-based driver genes in NSCLC.

Citation Format: Francisco Gimeno-Valiente, Carla Castignani, Elizabeth Larose-Cadieux, Kezhong Chen, Nana Mensah, Olga Chervova, Thomas Watkins, Pawan Dhami, Heli Vaikkinen, Andrew Feber, TRACERx Consortium, Jonas Demeulemeester, Miljana Tanic, Stephan Beck, Peter Van Loo, Charles Swanton, Nnennaya Kanu. Identification of convergent gene repression mechanisms through integrative genomic and DNA methylation analysis in TRACERx [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5710.

Abstract 3626: Genomic evolutionary patterns in matched pre-invasive and invasive lung disease in TRACERx

Introduction: The genomic landscape of pre-invasive lung disease, including AAH/AIS/MIA (atypical adenomatous hyperplasia, adenocarcinoma in situ, minimally invasive carcinoma) and squamous CIS (carcinoma in situ) which are considered to be precursors to lung adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC), has been profiled to a limited degree, due to the lack of matched samples within the same patient. Using TRACERx study we investigated the phylogenetic evolutionary patterns between matched pre-invasive and invasive lesions.

Methods: Post-operative pathology reports for 746 primary invasive tumors collected within TRACERx were screened to identify pre-invasive lesions that had been resected at the time of primary surgery. 50 pre-invasive lesions (21 AAH, 7 AIS, 6 MIA, 16 CIS) from 36 pts were subjected to whole exome sequencing with 119 matched tumor regions from 22 LUAD, 13 LUSC and 1 pleomorphic carcinoma. Phylogenetic relationships between pre-invasive and invasive lesions, timing of clonal divergence, mutational processes were investigated.

Results: Two major types of phylogenetic relationships were identified based on whether pre-invasive and invasive lesions shared a somatic common ancestor (SCA group; 7/22 LUAD, 11/13 LUSC) or not (non-SCA group; 15/22 LUAD, 2/13 LUSC, 1/1 pleomorphic carcinoma). Within SCA group, two evolutionary patterns were identified based on whether only clonal mutations or clonal and subclonal mutations were shared between pre-invasive and invasive lesions. 3/16 SCA pre-invasive lesions from ex-smokers were found to diverge from the invasive tumor years prior to diagnosis. Compared with non-SCA, SCA pre-invasive lesions harbored elevated mutational burden, APOBEC mutagenesis, chromosomal instability featured by increased loss of heterozygosity and somatic copy number alterations (SCNAs). Whole genome doubling was only detected in SCA pre-invasive lesions. In SCA LUAD, 3/7 exhibited clonal TP53 mutations, 3/7 exhibited clonal co-mutations of KEAP1 and STK11. In 5/15 non-SCA LUADs harboring a KRAS mutation, convergent KRAS mutation was detected in 4 matched pre-invasive and invasive lesions. Clonal focal gains on 3q21-29 (containing PIK3CA, ATR, SOX2) were detected in 10/11 SCA LUSC, suggesting that 3q gains may represent early events in tumor initiation. In the non-SCA group, convergent SCNAs encompassing oncogenes (PIK3CA, SOX2, FGFR3) or tumor suppressor genes (STK11, KEAP1, MGA) were detected.

Conclusions: We demonstrate that matched pre-invasive and invasive lesions fall in two distinct phylogenetic evolutionary groups: those that have a shared somatic common ancestor and those that do not. SCA pre-invasive lesions exhibit elevated APOBEC mutagenesis and chromosomal instability, shedding some light on the process of malignant transformation.

Citation Format: Haoran Zhai, Clare Puttick, David A. Moore, Michelle Dietzen, Sophia Ward, Maise Al Bakir, Thomas Watkins, Andrew Rowan, Selvaraju Veeriah, Robert Hynds, Oriol Pich, Nnennaya Kanu, TRACERx Consortium, Nicholas McGranahan, Charles Swanton, Mariam Jamal-Hanjani. Genomic evolutionary patterns in matched pre-invasive and invasive lung disease in TRACERx [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3626.

Outcomes Following Hypofractionated Stereotactic Radiotherapy to the Cavity After Surgery for Melanoma Brain Metastases

AIMS

Hypofractionated stereotactic radiotherapy (HSRT) to the cavity after surgical resection of brain metastases improves local control. Most reported cohorts include few patients with melanoma, a population known to have high rates of recurrence and neurological death. We aimed to assess outcomes in patients with melanoma brain metastases who received HSRT after surgery at two Australian institutions.

MATERIALS AND METHODS

A retrospective analysis was carried out including patients treated between January 2012 and May 2020. HSRT was recommended for patients with melanoma brain metastases at high risk of local recurrence after surgery. Treatment was delivered using appropriately commissioned linear accelerators. Routine follow-up included surveillance magnetic resonance imaging brain every 3 months for at least 2 years. Primary outcomes were overall survival, local control, incidence of radiological radionecrosis and symptomatic radionecrosis.

RESULTS

There were 63 cavities identified in 57 patients. The most common HSRT dose prescriptions were 24 Gy in three fractions and 27.5 Gy in five fractions. The median follow-up was 32 months in survivors. Local control was 90% at 1 year, 83% at 2 years and 76% at 3 years. Subtotal brain metastases resection (hazard ratio 12.5; 95% confidence interval 1.4-111; P = 0.0238) was associated with more local recurrence. Overall survival was 64% at 1 year, 45% at 2 years and 40% at 3 years. There were 10 radiological radionecrosis events (16% of cavities) during the study period, with 5% at 1 year and 8% at 2 years after HSRT. The median time to onset of radiological radionecrosis was 21 months (range 6-56). Of these events, three became symptomatic (5%) during the study period at a median time to onset of 26 months (range 21-32).

CONCLUSION

Cavity HSRT is associated with high rates of local control in patients with melanoma brain metastases. Subtotal resection strongly predicts for local recurrence after HSRT. Symptomatic radionecrosis occurred in 5% of cavities but increased to 8% of longer-term survivors.

Radiological Kinetics of Brain Metastases and Clinical Implications for Patients Treated With Stereotactic Radiosurgery

AIMS

Select patients with brain metastases receive stereotactic radiosurgery (SRS) with the objective of improving survival and intracranial disease control. Brain metastases number and volume are prognostic factors used to inform patient selection. The aim of this study was to assess the rate of change of brain metastases size and number (growth kinetics) between the diagnostic and day of SRS magnetic resonance imaging (MRI) scans.

MATERIALS AND METHODS

All patients treated with Gamma Knife SRS between October 2015 and April 2017 were included in this single-centre retrospective analysis. Brain metastases number and diameter were recorded at diagnosis and treatment. For patients with multiple brain metastases, the largest lesion was the index lesion. Distant intracranial control and overall survival were reported from the date of SRS.

RESULTS

In total, 146 patients received 156 episodes of SRS. The median interval between diagnostic and SRS MRI was 20 days (range 1-68). Interval growth in the index lesion of at least 3 mm or the development of a new brain metastasis was noted in 60.2% of patients. This was associated with age less than 60 years (P = 0.001), Eastern Cooperative Oncology Group (ECOG) performance status 2 or above (P = 0.04), non-small cell lung carcinoma (NSCLC) (P = 0.03) or melanoma histologies (P = 0.05) and uncontrolled extracranial disease (P = 0.05). These patients were also more likely to develop distant intracranial recurrence (P = 0.046). Clinically significant growth was not associated with scan interval or differences in overall survival. The Kaplan-Meier estimate of probability of survival at 12 months was 59.3% (95% confidence interval 46.7-75.2%) for all patients.

CONCLUSION

Intracranial progression between diagnosis and day of SRS is common. Risk factors are uncontrolled extracranial disease, poorer performance status, NSCLC or melanoma histologies and age less than 60 years. These patients would benefit from an MRI closer to treatment to inform patient selection and target delineation for SRS planning.

Trends in Dissonance Research and the Chapanis' Criticisms

A trend analysis of two of the methodological problems of cognitive dissonance research raised by the Chapanises indi cated (1) the criticism was valid, (2) over time the methods grad ually approximated the norms of the field, and (3) the Chapanis' critique did not influence the time trends appreciably, but was reflective of past problems.

Transfusion indications for patients with cancer

BACKGROUND

During the last few years, considerable focus has been given to the management of anemia and coagulopathies. This article provides current concepts of red blood cell (RBC) and plasma coagulation factor replacements.

METHODS

The literature was reviewed for clinical studies relevant to RBC transfusion indications and outcomes as well as for the uses of coagulation factor replacement products for coagulopathies most likely encountered in patients with cancer.

RESULTS

Most patients without complications can be treated with a hemoglobin level of 7 g/dL as an indication for RBC transfusion. However, the effects of disease among patients with cancer may cause fatigue, so transfusions at higher hemoglobin levels may be clinically helpful. Leukoreduced RBCs are recommended as standard therapy for all patients with cancer, most of whom do not develop coagulopathy. Transfusions to correct mild abnormalities are not indicated in this patient population. Data are inconclusive regarding the value of coagulation factor replacement for invasive procedures when the international normalized ratio is below 2.

CONCLUSIONS

Indications for RBC transfusion have become more conservative as data and experience have shown that patients can be safely and effectively maintained at lower hemoglobin levels. Coagulation factor replacement is unnecessary for most modest coagulopathies.

Tracking the genomic evolution of esophageal adenocarcinoma through neoadjuvant chemotherapy

Esophageal adenocarcinomas are associated with a dismal prognosis. Deciphering the evolutionary history of this disease may shed light on therapeutically tractable targets and reveal dynamic mutational processes during the disease course and following neoadjuvant chemotherapy (NAC). We exome sequenced 40 tumor regions from 8 patients with operable esophageal adenocarcinomas, before and after platinum-containing NAC. This revealed the evolutionary genomic landscape of esophageal adenocarcinomas with the presence of heterogeneous driver mutations, parallel evolution, early genome-doubling events, and an association between high intratumor heterogeneity and poor response to NAC. Multiregion sequencing demonstrated a significant reduction in thymine to guanine mutations within a CpTpT context when comparing early and late mutational processes and the presence of a platinum signature with enrichment of cytosine to adenine mutations within a CpC context following NAC. Esophageal adenocarcinomas are characterized by early chromosomal instability leading to amplifications containing targetable oncogenes persisting through chemotherapy, providing a rationale for future therapeutic approaches.

SIGNIFICANCE

This work illustrates dynamic mutational processes occurring during esophageal adenocarcinoma evolution and following selective pressures of platinum exposure, emphasizing the iatrogenic impact of therapy on cancer evolution. Identification of amplifications encoding targetable oncogenes maintained through NAC suggests the presence of stable vulnerabilities, unimpeded by cytotoxics, suitable for therapeutic intervention.

Maternal obesity and venous thromboembolism

The incidence of obesity in pregnancy has increased rapidly in the last decade. Obesity is a risk factor for venous thromboembolism outside of pregnancy and previous studies of maternal death in the UK have identified obesity as a risk factor in pregnancy. As a result the Royal College of Obstetricians and Gynaecologists have targeted obesity as a risk factor in evaluation of the need for thromboprophylaxis in pregnancy. This article highlights the evidence that obesity increases the risk of venous thromboembolism in pregnancy and the puerperium, discusses thromboprophylaxis and appropriate dosing in obese parturients and details the anaesthetic implications of the 2009 Royal College of Obstetricians and Gynaecologists' guidelines. More clinical studies are required to clarify the appropriate dose of low-molecular-weight heparin in an obese parturient.

rPSGL-Ig for improvement of early liver allograft function: a double-blind, placebo-controlled, single-center phase II study

The selectin antagonist known as recombinant P-selectin glycoprotein ligand IgG (rPSGL-Ig) blocks leukocyte adhesion and protects against transplantation ischemia reperfusion injury (IRI) in animal models. This randomized (1:1) single-center double-blind 47-patient phase 2 study with 6-month follow-up assessed rPSGL-Ig's safety and impact on early graft function at 1 mg/kg systemic dose with pretransplant allograft ex vivo treatment in deceased-donor liver transplant recipients. Safety was assessed in all patients, whereas efficacy was assessed in a prospectively defined per-protocol patient set (PP) by peak serum transaminase (TA) and bilirubin values, and normalization thereof. In PP patients, the incidence of poor early graft function (defined as peak TA >2500 U/L or bilirubin >10 mg/dL), average peak liver enzymes and bilirubin, normalization thereof and duration of primary and total hospitalization trended consistently lower in the rPSGL-Ig group compared to placebo. In patients with donor risk index above study-average, normalization of aspartate aminotransferase was significantly improved in the rPSGL-Ig group (p < 0.03). rPSGL-Ig treatment blunted postreperfusion induction versus placebo of IRI biomarker IP-10 (p < 0.1) and augmented cytoprotective IL-10 (p < 0.05). This is the first clinical trial of an adhesion molecule antagonist to demonstrate a beneficial effect on liver transplantation IRI and supported by therapeutic modulation of two hepatic IRI biomarkers.

A novel mechanism whereby BRCA1/1a/1b fine tunes the dynamic complex interplay between SUMO-dependent/independent activities of Ubc9 on E2-induced ERalpha activation/repression and degradation in breast cancer cells

BRCA1 dysfunction is associated with hormone-responsive cancers. We have identified a consensus SUMO modification site in the amino-terminal region of BRCA1/1a/1b proteins and the mutation in this potential SUMO acceptor site (K 109 to R) impaired their ability to bind and repress ligand-dependent ERalpha transcriptional activity in breast cancer cells. Furthermore, we have found SUMO E2-conjugating enzyme Ubc9 to bind BRCA1 proteins. We have mapped BRCA1 [within amino acids (aa) 1-182] as the minimum domain that is sufficient for in vitro binding to Ubc9 as well as for regulating ERalpha activity. BRCA1 Mutant #1 (K109 to R) was impaired in its ability to both bind, as well as modulate Ubc9 mediated SUMO-dependent/independent E2-induced ERalpha transcriptional activity in breast cancer cells. Similarly, BRCA1 cancer-predisposing mutation (61Cys-Gly) abrogated the ability to both bind Ubc9 as well as inhibit ERalpha activity suggesting physiological significance. Addition of BRCA1 but not Mutant #1 to E2-induced ERalpha in the presence of SUMO-1 and Ubc9 resulted in the degradation of ERalpha suggesting BRCA1 to be a putative SUMO-1 and Ubc9-dependent E3 ubiquitin ligase for ERalpha. This is the first report demonstrating the participation of Ubc9 in BRCA1 E3 ubiquitin ligase mediated degradation of ERalpha. These results suggest a novel function for BRCA1 in regulating the dynamic cycles of SUMO and ubiquitin modifications required for ERalpha turn over and deregulation of this molecular switch due to lack of BRCA1 results in ERalpha-negative/positive breast cancers. This study will help in designing novel BRCA1 function-based targeted treatment for breast cancers.

Gene set enrichment analysis to evaluate expression of autoantigens in lung cancer

e22048

Background: There is a well-established association between certain autoimmune diseases and the development of specific malignancies. It has been demonstrated that myositis-specific autoantigens are expressed at higher levels in tumors associated with myositis compared to normal tissue, suggesting that immune responses to antigens expressed in nascent tumors may contribute to the autoimmune process. Whether this observation is a general feature of autoantigen expression in tumor tissue, and whether the relative expression of these antigens is enriched in relation to the rest of the tumor transcriptome is currently unknown. Methods: Tumor tissue from ten lung cancer biopsies (adenocarcinoma (4), carcinoid (4), and squamous cell carcinoma (2)) and normal lung from the same patients were obtained. Total RNA was extracted and hybridized to Illumina Sentrix BeadChips. Hiearchical clustering was used to visualize the expression levels of 146 known autoantigens. Gene Set Enrichment Analysis was performed using 20 disease-specific autoantigen gene sets and 1892 gene sets from the Molecular Signatures Database. Protein levels of selected autoantigens were assessed by immunoblotting detergent tissue lysates. Results: Single-linkage hierarchical clustering analysis reveals groups of autoantigens that are differentially expressed between normal lung tissue, carcinoid tumors, and adenocarcinomas. Adenocarcinoma tumor samples were significantly enriched for myositis (nominal p-value <0.001, false discovery rate (FDR) q-value 0.009) and SLE autoantigens (p-value 0.004, FDR 0.029). Scleroderma autoantigens were enriched in carcinoid tumors (p-value 0.003, FDR 0.053). Increased protein expression of the autoantigens Mi-2 and topoisomerase-1 in carcinoid tumors was confirmed by immunoblotting. Conclusions: This study reveals that autoantigens targeted in several autoimmune diseases are both transcribed and expressed at high levels in malignancies known to associate with those disorders. While autoantigens comprise only a small fraction of the total transcriptome, they are disproportionately expressed in tumors known to associate with autoimmunity, supporting the hyporthesis that autoimmunity to these proteins may arise via nascent anti-tumor responses.

No significant financial relationships to disclose.

A multiple-site-specific heteroduplex tracking assay as a tool for the study of viral population dynamics

Rapidly evolving entities, such as viruses, can undergo complex genetic changes in the face of strong selective pressure. We have developed a modified heteroduplex tracking assay (HTA) capable of detecting the presence of single, specific mutations or sets of linked mutations. The initial application of this approach, termed multiple-site-specific (MSS) HTA, was directed toward the detection of mutations in the HIV-1 pro gene at positions 46, 48, 54, 82, 84, and 90, which are associated with resistance to multiple protease inhibitors. We demonstrate that MSS HTA is sensitive and largely specific to all targeted mutations. The assay allows the accurate and reproducible quantitation of viral subpopulations comprising 3% or more of the total population. Furthermore, we used MSS HTA in longitudinal studies of pro gene evolution in vitro and in vivo. In the examples shown here, populations turned over rapidly and more than one population was present frequently. To demonstrate the versatility of MSS HTA, we also constructed a probe sensitive to changes at positions 181 and 184 of the RT coding domain. Changes at these positions are involved in resistance to nevirapine and 2',3'-dideoxy-3'-thiacytidine (3TC), respectively. This assay easily detected the evolution of resistance to 3TC. MSS HTA provides a rapid and sensitive approach for detecting the presence of and quantifying complex mixtures of distinct genotypes, including genetically linked mutations, and, as one example, represents a useful tool for following the evolution of drug resistance during failure of HIV-1 antiviral therapy.

Identification of autoantibodies associated with rippling muscles and myasthenia gravis that recognize skeletal muscle proteins: possible relationship of antigens and stretch-activated ion channels

The role of mechanosensitive calcium channels in skeletal muscle physiology is not understood. This study takes advantage of an autoimmune neuromuscular disorder (myasthenia gravis associated with rippling muscles) to identify components in the skeletal muscle myocyte that may play a role in mechanosensitive calcium channel activity. Rippling muscles are characterized by stretch or percussion activated wave-like muscle contractions that do not require motor unit action potentials for propagation. Autoantibodies from the sera of patients with autoimmune rippling muscles (associated with myasthenia gravis) are directed against high molecular weight muscle proteins. Some of these proteins are uniquely recognized by antisera from patients with autoimmune rippling muscles. This suggests these autoantigens are distinct from those normally associated with myasthenia gravis, and may play a role in the mechanosensitive activation of muscle contraction.

Is kidney length a good predictor of kidney volume?

Kidney length is commonly used to determine kidney size; however, its relationship to kidney volume is not well established. This study evaluated the association between kidney length and kidney volume. Eighteen healthy adults (9 men and 9 women) consented to take part in this prospective study; all 18 underwent spiral computerized tomography (CT) of the kidneys, 14 of 18 also underwent kidney ultrasound. Kidney volume was measured by totaling the areas of the CT scan cuts, and kidney length was measured both on the kidney ultrasound and on the CT scan. Each independent variable, CT length (CTL) and ultrasound length (USL), was regressed against the dependent variable, kidney volume. Kidney length explained only 10% of the variability of the volume, although length x width was a better predictor of kidney volume (r = 0.72, P < 0.001). It was concluded that kidney length does not reliably predict kidney volume and that other methods, both clinical and radiologic, should be considered when a more exact determination of renal volume is clinically relevant.

Prostanoid production in rabbit corpus cavernosum: I. regulation by oxygen tension

PURPOSE

To investigate the effects of oxygen tension on prostanoid synthesis in rabbit penile corpus cavernosum tissue (RCC) in organ culture.

MATERIALS AND METHODS

Strips of rabbit corpus cavernosum were incubated in organ culture media under varying oxygen conditions (0%, 12% and 21% oxygen), in the presence or absence of acetylcholine and arachidonate stimulation. Prostanoids were measured in collected media by radioimmunoassay. Prostaglandin H synthase (PGHS) protein levels and mRNA PGHS expression were measured under both 0% and 21% oxygen conditions.

RESULTS

Basal and acetylcholine-stimulated PGI2 release was progressively diminished as a function of diminishing oxygen tension (pO2 from approximately 165 to 25 mm.Hg). The basal and stimulated production of other prostanoids, thromboxane A2, PGF2alpha, and PGE2, was also significantly inhibited under 0% oxygen (approximately 25 mm.Hg) conditions. However, incubation under 0% oxygen did not alter PGHS protein levels nor mRNA PGHS expression. Cavernosal strips incubated under 0% oxygen but supplemented with exogenous arachidonate (10 microM.) maintained significantly lower PGI2 production than tissues exposed to 21% oxygen (approximately 165 mm.Hg).

CONCLUSIONS

These data demonstrate that oxygen tension regulates prostaglandin production in corporal tissue. The reduction in prostanoid production during hypoxia can be attributed to inhibition of PGHS activity rather than the expression of the enzyme. In view of the role of PGI2 as an inhibitor of platelet aggregation and white cell-endothelial adhesion, our findings may provide mechanistic insight into the alteration in corporal blood homeostasis ischemic-hypoxic priapism.

Prostanoid production in rabbit corpus cavernosum: I. regulation by oxygen tension

PURPOSE

To investigate the effects of oxygen tension on prostanoid synthesis in rabbit penile corpus cavernosum tissue (RCC) in organ culture.

MATERIALS AND METHODS

Strips of rabbit corpus cavernosum were incubated in organ culture media under varying oxygen conditions (0%, 12% and 21% oxygen), in the presence or absence of acetylcholine and arachidonate stimulation. Prostanoids were measured in collected media by radioimmunoassay. Prostaglandin H synthase (PGHS) protein levels and mRNA PGHS expression were measured under both 0% and 21% oxygen conditions.

RESULTS

Basal and acetylcholine-stimulated PGI2 release was progressively diminished as a function of diminishing oxygen tension (pO2 from approximately 165 to 25 mm.Hg). The basal and stimulated production of other prostanoids, thromboxane A2, PGF2alpha, and PGE2, was also significantly inhibited under 0% oxygen (approximately 25 mm.Hg) conditions. However, incubation under 0% oxygen did not alter PGHS protein levels nor mRNA PGHS expression. Cavernosal strips incubated under 0% oxygen but supplemented with exogenous arachidonate (10 microM.) maintained significantly lower PGI2 production than tissues exposed to 21% oxygen (approximately 165 mm.Hg).

CONCLUSIONS

These data demonstrate that oxygen tension regulates prostaglandin production in corporal tissue. The reduction in prostanoid production during hypoxia can be attributed to inhibition of PGHS activity rather than the expression of the enzyme. In view of the role of PGI2 as an inhibitor of platelet aggregation and white cell-endothelial adhesion, our findings may provide mechanistic insight into the alteration in corporal blood homeostasis ischemic-hypoxic priapism.

gamma-Tocotrienol as a hypocholesterolemic and antioxidant agent in rats fed atherogenic diets

This study was designed to determine whether incorporation of gamma-tocotrienol or alpha-tocopherol in an atherogenic diet would reduce the concentration of plasma cholesterol, triglycerides and fatty acid peroxides, and attenuate platelet aggregability in rats. For six weeks, male Wistar rats (n = 90) were fed AIN76A semisynthetic test diets containing cholesterol (2% by weight), providing fat as partially hydrogenated soybean oil (20% by weight), menhaden oil (20%) or corn oil (2%). Feeding the ration with menhaden oil resulted in the highest concentrations of plasma cholesterol, low and very low density lipoprotein cholesterol, triglycerides, thiobarbituric acid reactive substances and fatty acid hydroperoxides. Consumption of the ration containing gamma-tocotrienol (50 mg/kg) and alpha-tocopherol (500 mg/kg) for six weeks led to decreased plasma lipid concentrations. Plasma cholesterol, low and very low density lipoprotein cholesterol, and triglycerides each decreased significantly (P < 0.001). Plasma thiobarbituric acid reactive substances decreased significantly (P < 0.01), as did the fatty acid hydroperoxides (P < 0.05), when the diet contained both chromanols. Supplementation with gamma-tocotrienol resulted in similar, though quantitatively smaller, decrements in these plasma values. Plasma alpha-tocopherol concentrations were lowest in rats fed menhaden oil without either chromanol. Though plasma alpha-tocopherol did not rise with gamma-tocotrienol supplementation at 50 mg/kg, gamma-tocotrienol at 100 mg/kg of ration spared plasma alpha-tocopherol, which rose from 0.60 +/- 0.2 to 1.34 +/- 0.4 mg/dL (P < 0.05). The highest concentration of alpha-tocopherol was measured in plasma of animals fed a ration supplemented with alpha-tocopherol at 500 mg/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship between dietary fatty acid, selenium, and degenerative cardiomyopathy

With the finding of an increasing number of cases of degenerative cardiomyopathy (DCM) amongst patients in Chongqing, Sichuan, People's Republic of China, an attempt has been made to delineate possible etiological factors. In this province endemic for Keshan disease and with considerable consumption of oils high in erucic acid, the latter does not appear to be an operative noxious agent in DCM. Additionally, it does not appear to be caused by excessive oxygen radicals, low levels of antioxidants or low selenium levels. However, lower omega-3 fatty acid levels along with higher serum lipids may be the mechanism, via higher thromboxane levels, of the production of the myocardial degeneration seen in DCM.

Effect of dietary menhaden, Canola and partially hydrogenated soy oil supplemented with vitamin E upon plasma lipids and platelet aggregation

Male Fisher rats were fed chow diets for two weeks after which they were divided into seven groups of ten rats each and fed 20% Canola, 20% menhaden, 20% partially hydrogenated soy oil (PHSO) or chow only, with or without 500 mg/Kg dietary vitamin E in chow containing 2% cholesterol for six weeks. Triglycerides were lower in the menhaden group and were essentially the same in the E supplemented groups as in their unsupplemented cohorts. Plasma cholesterol was higher in the Canola, and lower in the menhaden, groups, compared to the PHSO group. Cholesterol was the same in the E supplemented groups as in their unsupplemented cohorts. Plasma thiobarbituric acid reactant substances (TBARS) were higher in the menhaden group, compared to the chow group. Vitamin E supplementation lowered TBARS in the menhaden and PHSO groups, compared to the unsupplemented cohorts. Collagen induced platelet aggregation was lower in both Canola and menhaden groups, compared to the PHSO group. Vitamin E supplementation lowered collagen induced platelet aggregation only in the PHSO group. Thrombin induced platelet aggregation was lower in the Canola group, compared to the PHSO group. Vitamin E supplementation did not affect thrombin induced platelet aggregation compared to unsupplemented cohorts. Plasma vitamin E levels were lowest in the menhaden supplemented group compared to all other groups not receiving E, suggesting a greater requirement for E in this group. Finally, vitamin E supplementation raised the plasma E levels in all groups except the menhaden group when compared to unsupplemented cohorts.

Effect of dietary canola and reference oils upon serum lipids and platelet aggregation

To compare Canola a terrestrial (n-3) oil with fish oil (n-3) and common vegetable oil (n-6) in decreasing serum lipids and platelet aggregation, various oils were included in Chow-based diets and fed to rats in an eight-weeks feeding trial. The Chow diet contained 2% cholesterol along with either Canola, menhaden, safflower, or partially hydrogenated soy oil, or no oil addendum. The menhaden oil group was the only one to show a significant reduction in serum cholesterol and triglycerides and at the same time yielded the most uniform decrease in platelet aggregability. However, this same group was also the only one to show a decrease in serum tocopherol levels, suggesting that improving an atherogenic risk profile may require antioxidant supplementation. In these rat trials, Canola oil supplementation did not yield the same results measured during menhaden supplementation.

CT for determining the results of treatment of fractures of the wrist

Eighteen CT examinations of the wrist were performed in 13 patients to evaluate the results of treatment for carpal fractures. In four cases with metal objects and in seven with cast materials, there was no difficulty achieving adequate CT studies. In 13 cases CT was found to be helpful in determining bony union in the presence of advanced osteoporosis. In six cases CT was excellent in evaluating bone-graft incorporation. CT affords improved detection of fractures perpendicular to the plane of the scan and also shows small areas of bone disruption, even with osteoporosis. Axial CT images can evaluate Lister's tubercle, a bony prominence on the dorsum of the distal radius, for hypertrophy, which can occur secondary to traumatic and degenerative changes. A hypertrophied tubercle can impinge on the extensor pollicis longus tendon and cause atrophy and disruption. The high cost of CT is offset by the possibility of reducing the patient's period of immobilization and, thereby, the length of time the patient is unable to participate in normal activities. In addition, since CT is often definitive, the number of supplemental or follow-up radiologic procedures or clinical appointments should be reduced. We conclude that CT is useful in evaluating the results of treatment of wrist injuries.