GALAD score and a proposal for GALADUS model for detecting hepatocellular carcinoma in Vietnamese patients with chronic liver disease.

OBJECTIVE: The GALAD score, a serum biomarker-based model, predicts the likelihood of hepatocellular carcinoma (HCC) in patients with chronic liver disease. We evaluated the performance of the GALAD score compared to that of liver ultrasound in detecting HCC. PATIENTS AND METHODS: This study recruited a group of 136 patients with HCC and a control group of 436 patients with cirrhosis or chronic hepatitis B or hepatitis C. The performance of the GALAD score and ultrasound in detecting HCC in these patients was analyzed using the area under the receiver operating characteristic curve (AUC). The sensitivity and specificity of the optimal GALAD score were compared to those of ultrasound. RESULTS: The AUC of the GALAD score for detecting HCC was 0.940 [95% confidence interval (CI) 0.92-0.96], higher than that of ultrasound [0.939 (0.91-0.96), p < 0.001]. At a threshold of 1.24, the GALAD score had a sensitivity of 91.2% and a specificity of 81.9% for detecting HCC. The AUC of the GALAD score for early HCC detection was 0.75 (95% CI 0.71-0.80, p < 0.001; threshold 1.13, sensitivity 87.5%, specificity 67.8%, p < 0.001). The combination of GALAD and ultrasound (GALADUS score) showed further improvement, achieving an AUC of 0.97 (95% CI 0.96-0.99; cut-off point 1.37, sensitivity 95.6%, specificity 89.2%, p < 0.001). CONCLUSIONS: In our study, the GALADUS score showed improved performance compared to the GALAD score. Therefore, we suggest that the performance of the GALAD score should be reconsidered and that it should be evaluated in combination with ultrasound for HCC detection.

Relationship between PET/CT images and KRAS gene mutations in colorectal cancer in Vietnamese patients.

OBJECTIVE: We conducted this study to determine the relationship among standardized uptake value (SUV), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) indexes of Flourine-18 fluorodeoxyglucose positron emission tomography/computed tomography18 (FDG-PET/CT) imaging and Kirsten rat sarcoma (KRAS) gene mutations in colorectal cancer (CRC). PATIENTS AND METHODS: This cross-sectional study was conducted in Bach Mai Hospital from 2020 to 2022. It included newly diagnosed CRC patients who underwent PET/CT examination prior to primary tumor resection. The maximum SUV (SUVmax - SUVmean), MTV, and TLG were considered. All pathologically confirmed CRC patients were accepted with further KRAS mutation status analysis. RESULTS: We enrolled 63 newly diagnosed CRC patients who underwent PET/CT examination prior to primary tumor resection. Among them, 31 (49.2%) patients had KRAS gene mutation. Patients with KRAS mutation status showed significantly different and higher SUVmax (p-value = 0.025), SUVmax t/b (p-value = 0.013), SUVmax t-b (p-value = 0.014), MTV (p-value = 0.023), and TLG (p-value = 0.011) than patients with WT KRAS. Other characteristics, including age, gender, tumor location, SUVb, SUVmean, SUVmax of lymph nodes, and SUVmax of liver metastasis, were insignificantly different between the two groups of patients with KRAS mutation status. Receiver operating curve analysis showed that the area under the curve was 0.672 for SUVmax (p-value = 0.019), SUVt/b (p-value = 0.045), and SUVt-b (p-value = 0.020). CONCLUSIONS: We observed a relationship, considering the quantitative parameters (SUVmax, SUVmax, SUVmax t-b, MTV, and TLG), between 18FDG-PET/CT images and the KRAS gene mutation in CRC by analyzing 63 patients prior to treatment.

Using the health beliefs model to explore children's attitudes and beliefs on air pollution.

OBJECTIVES: Traffic-related air pollution (TRAP) negatively impacts children's health. Self-protective measures are available, but population uptake is variable. It is essential to understand human beliefs and behaviours related to air pollution in order to understand the lack of self-protection in communities. As a prelude to undertaking a comprehensive assessment of children's attitudes and beliefs on the health effects of TRAP exposure, we sought to develop and validate an appropriate instrument. STUDY DESIGN: This study used exploratory sequential mixed methods. METHODS: This instrument, based on the constructs of the health belief model (HBM), aimed to determine factors predicting wearing a mask to protect against TRAP exposure. An initial literature-based questionnaire was modified using in-depth interviews, focus group discussions, and a quantitative survey pilot. This study included 121 school students and nine professional experts in Vietnam. The questionnaire was tested for content validity, agreement, test-retest reliability, and internal consistency. RESULTS: The concordance of questionnaire items between two repeated assessments ranged from 47.2% to 78.3%, intraclass correlation coefficients ranged from 0.16 to 0.87 and Cronbach's internal reliability coefficient for the instrument was 0.60. CONCLUSION: The self-administered instrument, based on the HBM, is suitable to understand health attitudes and beliefs related to self-protective behaviours to reduce TRAP exposure.

Seasonal temperature patterns and durations of acceptable temperature range in houses in Brisbane, Australia.

A paradigm shift to the use of indoor rather than outdoor temperature to estimate the exposure risk of low and high temperatures is vital for better prediction of temperature health effects and timely health warnings, and will also assist in understanding the influence of temperature on energy consumption and comfort. This study aimed to quantify the percentage of hours during the year that indoor temperature (living room) was in the extended comfort band (18-28 °C) of a subtropical climate, and identify the diurnal pattern of indoor temperatures in different seasons. Data used was collected in a previous study on the association between indoor and outdoor temperature. A k-shape cluster analysis resulted in two clusters of indoor temperature patterns for both weekdays and weekends. A bimodal pattern was identified during the cool season and a flat top pattern for the warm season, with many variations at weekends. These patterns can be attributed to the influence of cooling and heating processes depending on the season as well as occupancy, occupants' interference, and building materials. During the intermediate season, a sinusoidal pattern was observed for both weekdays and weekends because occupants likely relied on outdoor temperature conditions which were similar to those expected indoors without heating or cooling devices. The percentage of hours in which the indoor temperature of the houses ranged within the extended comfort band was 72-97% throughout the year, but for the coldest and hottest months it was 50-75%. These findings show that Brisbane residents are at possible risk of exposure to cold and hot temperatures due to the poor thermal performance of houses, and confirm that there is no standard indoor temperature pattern for all houses.

Surveillance improves survival of patients with hepatocellular carcinoma: a prospective population-based study.

OBJECTIVES: To determine the factors associated with survival of patients with hepatocellular carcinoma (HCC) and the effect of HCC surveillance on survival. DESIGN, SETTING AND PARTICIPANTS: Prospective population-based cohort study of patients newly diagnosed with HCC in seven tertiary hospitals in Melbourne, 1 July 2012 - 30 June 2013. MAIN OUTCOME MEASURES: Overall survival (maximum follow-up, 24 months); factors associated with HCC surveillance participation and survival. RESULTS: 272 people were diagnosed with incident HCC during the study period; the most common risk factors were hepatitis C virus infection (41%), alcohol-related liver disease (39%), and hepatitis B virus infection (22%). Only 40% of patients participated in HCC surveillance at the time of diagnosis; participation was significantly higher among patients with smaller median tumour size (participants, 2.8 cm; non-participants, 6.0 cm; P < 0.001) and earlier Barcelona Clinic Liver Cancer (BCLC) stage disease (A/B, 59%; C/D, 25%; P < 0.001). Participation was higher among patients with compensated cirrhosis or hepatitis C infections; it was lower among those with alcohol-related liver disease or decompensated liver disease. Median overall survival time was 20.8 months; mean survival time was 18.1 months (95% CI, 16.6-19.6 months). Participation in HCC surveillance was associated with significantly lower mortality (adjusted hazard ratio [aHR], 0.60; 95% CI, 0.38-0.93; P = 0.021), as were curative therapies (aHR, 0.33; 95% CI, 0.19-0.58). Conversely, higher Child-Pugh class, alpha-fetoprotein levels over 400 kU/L, and later BCLC disease stages were each associated with higher mortality. CONCLUSIONS: Survival for patients with HCC is poor, but may be improved by surveillance, associated with the identification of earlier stage tumours, enabling curative therapies to be initiated.

Tubulogenesis of co-cultured human iPS-derived endothelial cells and human mesenchymal stem cells in fibrin and gelatin methacrylate gels.

Here, we investigate the tubulogenic potential of commercially-sourced iPS-ECs with and without supporting commercially-sourced hMSCs within 3D natural fibrin or semi-synthetic gelatin methacrylate (GelMA) hydrogels. We developed a selectable dual color third generation lentiviral reporter (hEF1α-H2B-mOrange2-IRES-EGFP PGK-Puro) to differentially label the nucleus and cytoplasm of iPS-ECs which allowed real-time tracking of key steps of vascular morphogenesis such as vacuole formation and coalescence to form shared multicellular lumens. We implement 3D quantification of the network character and validate that transduced and untransduced iPS-ECs can form tubules in fibrin with or without supporting hMSCs. In addition to natural fibrin gels, we also investigated tubulogenesis in GelMA, a semi-synthetic material that has received increased interest due to its ability to be photopatterned and 3D printed, and which may thus boost development of complex 3D models for regenerative medicine studies. We find that iPS-ECs alone have a muted tubulogenic response within GelMA, but that their tubulogenic response is enhanced when they are co-cultured with a small fraction of hMSCs (2% of total cells). Our work bolsters previous findings by validating established tubulogenic mechanisms with commercially available iPS-ECs, and we expect our findings will benefit biologic studies of vasculogenesis and will have applications in tissue engineering to pre-vascularize tissue constructs which are fabricated with advanced photopatterning and three-dimensional printing.

MARCO variants are associated with phagocytosis, pulmonary tuberculosis susceptibility and Beijing lineage.

Macrophage receptor with collagenous structure (MARCO) has an important role in the phagocytosis of Mycobacterium tuberculosis (M. tuberculosis). We hypothesized that MARCO polymorphisms are associated with phagocytosis, tuberculosis (TB) disease susceptibility and presentation, and infecting lineage. We used a human cellular model to examine how MARCO genotype mediates the immune response; a case-control study to investigate tuberculosis host genetic susceptibility; and a host-pathogen genetic analysis to study host-pathogen interactions. Two MARCO heterozygous (AG) genotypes (single-nucleotide polymorphisms rs2278589 and rs6751745) were associated with impaired phagocytosis of M. tuberculosis trehalose 6,6'-dimycolate-cord factor and ß-glucan-coated beads in macrophages. The heterozygous genotypes of rs2278589 and rs6751745 were also associated with increased risk of pulmonary TB (PTB; rs2278589, P=0.001, odds ratio (OR)=1.6; rs6751745, P=0.009, OR=1.4), and with severe chest X-ray abnormalities (P=0.007, OR=1.6). These two genotypes were also associated with the Beijing lineage (rs2278589, P=0.001, OR=1.7; rs6751745, P=0.01, OR=1.5). Together, these results suggest that MARCO polymorphisms may regulate phagocytosis of M. tuberculosis and susceptibility and severity of PTB. They also suggest MARCO genotype and Beijing strains may interact to increase the risk of PTB.

Novel population-based study finding higher than reported hepatocellular carcinoma incidence suggests an updated approach is needed.

UNLABELLED: Hepatocellular carcinoma (HCC) incidence is rising rapidly in many developed countries. Primary epidemiological data have invariably been derived from cancer registries that are heterogeneous in data quality and registration methodology; many registries have not adopted current clinical diagnostic criteria for HCC and still rely on histology for classification. We performed the first population-based study in Australia using current diagnostic criteria, hypothesizing that HCC incidence may be higher than reported. Incident cases of HCC (defined by American Association for the Study of Liver Diseases diagnostic criteria or histology) were prospectively identified over a 12-month period (2012-2013) from the population of Melbourne, Australia. Cases were captured from multiple sources: admissions to any of Melbourne's seven tertiary hospitals; attendances at outpatients; and radiology, pathology, and pharmacy services. Our cohort was compared to the Victorian Cancer Registry (VCR) cohort (mandatory notified cases) for the same population and period, and incidence rates were compared for both cohorts. There were 272 incident cases (79% male; median age: 65 years) identified. Cirrhosis was present in 83% of patients, with hepatitis C virus infection (41%), alcohol (39%), and hepatitis B virus infection (22%) the commonest etiologies present. Age-standardized HCC incidence (per 100,000, Australian Standard Population) was 10.3 (95% confidence interval [CI]: 9.0-11.7) for males and 2.3 (95% CI: 1.8 to 3.0) for females. The VCR reported significantly lower rates of HCC: 5.3 (95% CI: 4.4 to 6.4) and 1.0 (95% CI: 0.7 to 1.5) per 100,000 males and females respectively (P < 0.0001). CONCLUSIONS: HCC incidence in Melbourne is 2-fold higher than reported by cancer registry data owing to under-reporting of clinical diagnoses. Adoption of current diagnostic criteria and additional capture sources will improve registry completeness. Chronic viral hepatitis and alcohol remain leading causes of cirrhosis and HCC.

A peptide that inhibits function of Myristoylated Alanine-Rich C Kinase Substrate (MARCKS) reduces lung cancer metastasis.

Myristoylated Alanine-Rich C Kinase Substrate (MARCKS), a substrate of protein kinase C, is a key regulatory molecule controlling mucus granule secretion by airway epithelial cells as well as directed migration of leukocytes, stem cells and fibroblasts. Phosphorylation of MARKCS may be involved in these responses. However, the functionality of MARCKS and its related phosphorylation in lung cancer malignancy have not been characterized. This study demonstrated elevated levels of MARCKS and phospho-MARCKS in highly invasive lung cancer cell lines and lung cancer specimens from non-small-cell lung cancer patients. siRNA knockdown of MARCKS expression in these highly invasive lung cancer cell lines reduced cell migration and suppressed PI3K (phosphatidylinositol 3'-kinase)/Akt phosphorylation and Slug level. Interestingly, treatment with a peptide identical to the MARCKS N-terminus sequence (the MANS peptide) impaired cell migration in vitro and also the metastatic potential of invasive lung cancer cells in vivo. Mechanistically, MANS peptide treatment resulted in a coordination of increase of E-cadherin expression, suppression of MARCKS phosphorylation and AKT/Slug signalling pathway but not the expression of total MARCKS. These results indicate a crucial role for MARCKS, specifically its phosphorylated form, in potentiating lung cancer cell migration/metastasis and suggest a potential use of MARCKS-related peptides in the treatment of lung cancer metastasis.

Mitochondria-derived superoxide links to tourniquet-induced apoptosis in mouse skeletal muscle.

Our previous study has reported that superoxide mediates ischemia-reperfusion (IR)-induced necrosis in mouse skeletal muscle. However, it remains poorly understood whether IR induces apoptosis and what factors are involved in IR-induced apoptosis in skeletal muscle. Using a murine model of tourniquet-induced hindlimb IR, we investigated the relationship between mitochondrial dysfunction and apoptosis in skeletal muscle. Hindlimbs of C57/BL6 mice were subjected to 3 h ischemia and 4 h reperfusion via placement and release of a rubber tourniquet at the greater trochanter. Compared to sham treatment, tourniquet-induced IR significantly elevated mitochondria-derived superoxide production, activated opening of mitochondrial permeability transition pore (mPTP), and caused apoptosis in the gastrocnemius muscles. Pretreatment with a superoxide dismutase mimetic (tempol, 50 mg/kg) or a mitochondrial antioxidant (co-enzyme Q(10), 50 mg/kg) not only decreased mitochondria-derived superoxide production, but also inhibited mPTP opening and apoptosis in the IR gastrocnemius muscles. Additionally, an inhibitor of mPTP (cyclosporine A, 50 mg/kg) also inhibited both mPTP opening and apoptosis in the IR gastrocnemius muscles. These results suggest that mitochondria-derived superoxide overproduction triggers the mPTP opening and subsequently causes apoptosis in tourniquet-induced hindlimb IR.

Alterations of calcium channels and cell excitability in intracardiac ganglion neurons from type 2 diabetic rats.

Clinical study has demonstrated that patients with type 2 diabetes with attenuated arterial baroreflex have higher mortality rate compared with those without arterial baroreflex dysfunction. As a final pathway for the neural control of the cardiac function, functional changes of intracardiac ganglion (ICG) neurons might be involved in the attenuated arterial baroreflex in the type 2 diabetes mellitus (T2DM). Therefore, we measured the ICG neuron excitability and Ca(2+) channels in the sham and T2DM rats. T2DM was induced by a combination of both high-fat diet and low-dose streptozotocin (STZ, 30 mg/kg ip) injection. After 12-14 wk of the above treatment, the T2DM rats presented hyperglycemia, hyperlipidemia, and insulin resistance but no hyperinsulinemia, which closely mimicked the clinical features of the patients with T2DM. Data from immunofluorescence staining showed that L, N, P/Q, and R types of Ca(2+) channels were expressed in the ICG neurons, but only protein expression of N-type Ca(2+) channels was decreased in the ICG neurons from T2DM rats. Using whole cell patch-clamp technique, we found that T2DM significantly reduced the Ca(2+) currents and cell excitability in the ICG neurons. ω-Conotoxin GVIA (a specific N-type Ca(2+) channel blocker, 1 µM) lowered the Ca(2+) currents and cell excitability toward the same level in sham and T2DM rats. These results indicate that the decreased N-type Ca(2+) channels contribute to the suppressed ICG neuron excitability in T2DM rats. From this study, we think high-fat diet/STZ injection-induced T2DM might be an appropriate animal model to test the cellular and molecular mechanisms of cardiovascular autonomic dysfunction.

Tourniquet-induced acute ischemia-reperfusion injury in mouse skeletal muscles: Involvement of superoxide.

Although arterial limb tourniquet is one of the first-line treatments to prevent exsanguinating hemorrhage in both civilian pre-hospital and battlefield casualty care, prolonged application of a limb tourniquet can lead to serious ischemia-reperfusion injury. However, the underlying pathomechanisms of tourniquet-induced ischemia-reperfusion injury are still poorly understood. Using a murine model of acute limb ischemia-reperfusion, we investigated if acute limb ischemia-reperfusion injury is mediated by superoxide overproduction and mitochondrial dysfunction. Hind limbs of C57/BL6 mice were subjected to 3h ischemia and 4h reperfusion via placement and release of a rubber tourniquet at the greater trochanter. Approximately 40% of the gastrocnemius muscle suffered infarction in this model. Activities of mitochondrial electron transport chain complexes including complex I, II, III, and IV in the gastrocnemius muscle were decreased in the ischemia-reperfusion group compared to sham. Superoxide production was increased while activity of manganese superoxide dismutase (MnSOD, the mitochondria-targeted SOD isoform) was decreased in the ischemia-reperfusion group compared to the sham group. Pretreatment with tempol (a SOD mimetic, 50mg/kg) or co-enzyme Q(10) (50mg/kg) not only decreased the superoxide production, but also reduced the infarct size and normalized mitochondrial dysfunction in the gastrocnemius muscle. Our results suggest that tourniquet-induced skeletal muscle ischemia-reperfusion injuries including infarct size and mitochondrial dysfunction may be mediated via superoxide overproduction and reduced antioxidant activity. In the future, this murine ischemia-reperfusion model can be adapted to mechanistically evaluate anti-ischemic molecules in tourniquet-induced skeletal muscle injury.

Reduced expression and activation of voltage-gated sodium channels contributes to blunted baroreflex sensitivity in heart failure rats.

Voltage-gated sodium (Na(v)) channels are responsible for initiation and propagation of action potential in the neurons. To explore the mechanisms of chronic heart failure (CHF)-induced baroreflex dysfunction, we measured the expression and current density of Na(v) channel subunits (Na(v)1.7, Na(v)1.8, and Na(v)1.9) in the aortic baroreceptor neurons and investigated the role of Na(v) channels in aortic baroreceptor neuron excitability and baroreflex sensitivity in sham and CHF rats. CHF was induced by left coronary artery ligation. The development of CHF (6-8 weeks after the coronary ligation) was confirmed by hemodynamic and morphological characteristics. Immunofluorescent data indicated that Na(v)1.7 was expressed in A-type (myelinated) and C-type (unmyelinated) nodose neurons, but Na(v)1.8 and Na(v)1.9 were expressed only in C-type nodose neurons. Real-time RT-PCR and Western blot data showed that CHF reduced mRNA and protein expression levels of Na(v) channels in nodose neurons. In addition, using the whole-cell patch-clamp technique, we found that Na(v) current density and cell excitability of the aortic baroreceptor neurons were lower in CHF rats than that in sham rats. Aortic baroreflex sensitivity was blunted in anesthetized CHF rats, compared with that in sham rats. Furthermore, Na(v) channel activator (rATX II, 100 nM) significantly enhanced Na(v) current density and cell excitability of aortic baroreceptor neurons and improved aortic baroreflex sensitivity in CHF rats. These results suggest that reduced expression and activation of the Na(v) channels are involved in the attenuation of baroreceptor neuron excitability, which subsequently contributes to the impairment of baroreflex in CHF state.

What is the evidence of a role for host genetics in susceptibility to influenza A/H5N1?

The apparent family clustering of avian influenza A/H5N1 has led several groups to postulate the existence of a host genetic influence on susceptibility to A/H5N1, yet the role of host factors on the risk of A/H5N1 disease has received remarkably little attention compared to the efforts focused on viral factors. We examined the epidemiological patterns of human A/H5N1 cases, their possible explanations, and the plausibility of a host genetic effect on susceptibility to A/H5N1 infection. The preponderance of familial clustering of cases and the relative lack of non-familial clusters, the occurrence of related cases separated by time and place, and the paucity of cases in some highly exposed groups such as poultry cullers, are consistent with a host genetic effect. Animal models support the biological plausibility of genetic susceptibility to A/H5N1. Although the evidence is circumstantial, host genetic factors are a parsimonious explanation for the unusual epidemiology of human A/H5N1 cases and warrant further investigation.

Prevalence of structural central nervous system abnormalities in early-onset type 1 diabetes mellitus.

OBJECTIVE: To characterize the effects of severe hypoglycemia on the developing brain in children with early-onset type 1 diabetes mellitus (T1DM). STUDY DESIGN: Children diagnosed with T1DM before age 6 years were studied. Those with prospectively monitored severe hypoglycemia (coma/seizure; n = 32) were compared with age-matched peers (n = 30) with no history of such events using magnetic resonance imaging. Glycemic control (evaluated based on glycated hemoglobin [HbA(lc)] level), episodes of diabetic ketoacidosis (DKA), and clinical variables were monitored continuously since diagnosis in all subjects. RESULTS: Mean HbA(lc) from diagnosis and the duration of T1DM were similar in those with and without a history of severe hypoglycemia (9.0% +/- 0.9% vs 8.8% +/- 0.9%; 7.2 +/- 2.7 years vs 6.7 +/- 2.3 years). A high prevalence of central nervous system (CNS) structural abnormalities was detected (29%), and mesial temporal sclerosis (MTS) was detected in 16% of the total sample (n = 62). The presence of MTS was not associated with a history of severe hypoglycemia or DKA. Analysis of brain matter volumes suggested relatively less gray matter density in those subjects with a history of severe hypoglycemia. CONCLUSIONS: Early age of onset of T1DM per se is associated with a high incidence of CNS abnormalities, particularly MTS, suggesting hippocampal damage. Early-onset severe hypoglycemia may have an effect on gray matter volume.

Improved preservation of coronary endothelial function with Celsior compared with blood and crystalloid solutions in heart transplantation.

BACKGROUND: Endothelial injury from preservation solutions has been implicated in acute coronary vasospasm and pathologic activation of the endothelium, which can contribute to the development of graft coronary vasculopathy after heart transplantation. Preservation solutions with a powerful antioxidant capacity may decrease the occurrence of these complications. MATERIALS AND METHODS: This study was designed to evaluate the effect of Celsior (an anti-oxidant solution specifically designed for cardiac preservation) in a model of heart preservation (4 hours at 4 degrees C to reproduce the situation encountered in clinical heart transplantation) compared two commonly used cardioplegic and preservation strategies on coronary endothelial function. Endothelium-dependent relaxation of normal porcine epicardial coronary arteries to serotonin (5-HT, an agonist that activates 5-HT(1d) receptors coupled to Gi proteins) and bradykinin (BK, which activates B2 receptors coupled to Gq proteins) was studied in standard organ chamber experiments in the following groups: a control group was submitted to immediate excision without cardioplegia and preserved in saline solution (0.9% NaCl) for 4 hours (Group 1); two groups had cardioplegia induced with a crystalloid solution and were stored for 4 hours in saline (Group 2) or 4 hours in Celsior solution (Group 3); and two groups had cardioplegia induced with normothermic blood cardioplegia and were stored for 4 hours in the saline (Group 4), or 4 hours in Celsior solution (Group 5). Finally, two groups underwent cardioplegia with Celsior and were stored for 4 hours in saline (Group 6), or 4 hours in the Celsior solution (Group 7). All cardioplegia solutions were at 4 degrees C (except blood cardioplegia at 37 degrees C) and all preservations solutions were at 4 degrees C. RESULTS: Endothelium-dependent relaxations to serotonin were significantly decreased in all groups except the Celsior + Celsior group compared with the control group. There were no significant differences in relaxation to bradykinin except in one group. Use of the Celsior solution for induction of cardioplegia and storage better preserved endothelium-dependent G-protein-mediated relaxation compared with the other arrest and preservation strategies. CONCLUSIONS: The observed effect may be associated with an improvement in both short- and long-term outcome in heart transplantation, especially because these alterations may be further compounded by reperfusion.

Influence of stent expansion states on platelet deposition in an extracorporeal porcine arteriovenous shunt model using a multichannel perfusion chamber.

Limited data are available about incomplete stent expansion (SE) on platelet deposition (PD). We examined PD following different SE using an extracorporeal porcine arteriovenous shunt model to which a perfusion chamber with four parallel silastic tubes were connected. Blood flow was set at a 20 and 100 mL/min in 1.8 and 3.1 mm diameter tubes, respectively. P154 stents were deployed completely (Group A, n=15) or incompletely (Group B, n=15) in 1.8 mm (n=13) and 3.1 mm (n=17) tubes. 51Cr-labelled platelet autologous blood was injected 1 hr before the perfusion. After 15 min-perfusion, the testing tubes were assessed for radioactivity counts. In-stent cross sectional area was measured by intravascular ultrasound. There was a significant difference in PD between group A and B regardless of channel size (118+/-18.4 vs 261.4+/-52.1 pits x 10(6)/cm2, p<0.05). With adjusted shear rate and similar stenosis, PD was similar in both tubes. In smaller 1.8 mm tubes, a stenosis as subtle as 10% was associated with a significant PD difference (226.1+/-20 vs 112.9+/-20.5 plts x 10(6)/cm2, p<0.005). This model enabled a repetitive, simultaneous comparison of PD following different SE states. It seems that the quality of SE remains crucial in smaller channels.

Protein histidine phosphorylation: increased stability of thiophosphohistidine.

Posttranslational phosphorylation of proteins is an important event in many cellular processes. Whereas phosphoesters of serine, threonine and tyrosine have been extensively studied, only limited information is available for other amino acids modified by a phosphate group. The formation of phosphohistidine residues in proteins has been discovered in prokaryotic organisms as well as in eukaryotic cells. The ability to biochemically analyze phosphohistidine residues in proteins, however, is severely hampered by its extreme lability under acidic conditions. In our studies we have found that by replacing the phosphate linked to the histidine residue with a thiophosphate, a phosphohistidine derivative with increased stability is formed. This allows the analysis of phosphohistidine-containing proteins by established biochemical techniques and will greatly aid in the investigation of the role of this posttranslational modification in cellular processes.

Ischemic threshold during cold blood cardioplegic arrest: monitoring with tissue pH and pO2.

BACKGROUND: Several studies have suggested that measuring interstitial pH and pO2, may be useful to monitor ischemia throughout cardioplegic arrest during cardiac surgery. METHODS: To evaluate the levels of myocardial tissue pH and pO2 that correlate with significant ischemia, 7 dogs underwent cold blood cardioplegic arrest and subsequent incremental episodes of 5, 10, 20 and 40 min of ischemia interrupted by cardioplegic infusion over 10-min periods. RESULTS: Myocardial tissue pH and pO2 were monitored with probes implanted in the anterior and lateral walls of the left ventricle. The release of CK, troponine T and lactate was measured before and after each episode of ischemic arrest. Tissue pH decreased from 7.08+/-0.15 to 7.03+/-0.15 (p>0.05), 7.21+/-0.15 to 7.07+/-0.11 (p>0.05), 7.17+/-0.15 to 6.82+/-0.14 (p<0.05) and 7.0+/-0.18 to 6.63+/-0.08 (p<0.05) after 5, 10, 20 and 40 min of ischemic arrest. Tissue pO2 decreased from 74+/-10 to 38+/-11 mmHg (p<0.05), 83+/-16 to 18+/-4 mmHg (p<0.05), 9+/-22 to 14+/-5 mmHg (p<0.05) and 64+/-24 to 16+/-10 mmHg (p<0.05) after 5, 10, 20 and 40 min of ischemic arrest. CK, troponine T and lactate serum levels increased significantly only following 40 min of ischemic arrest. Myocardial temperature decreased to an average minimum of 14+/-1 degrees C during cardioplegic infusion. CONCLUSIONS: A myocardial tissue pH lower than 7.04 (90% CI, upper limit of 6.82+/-0.14) and a tissue pO2 lower than 22 mmHg (90% CI, upper limit of 14+/-5 mmHg) correlate with anaerobic metabolism and myocardial ischemia during cold cardioplegic arrest.

Myocardial distribution of cardioplegia administered by antegrade and retrograde routes to ischemic myocardium.

OBJECTIVE: To study the distribution of a cardioplegic solution delivered by antegrade and retrograde routes to ischemic myocardium. Retrograde administration has been suggested to improve protection of the ischemic myocardium. However, there are insufficient data on perfusion of ischemic and necrotic zones by the retrograde route. DESIGN: A laboratory study in dogs. METHOD: In 12 dogs, 500 mL of hyperkalemic crystalloid cardioplegia containing 0.5 mCi of thallium-201 was injected antegradely or retrogradely through the coronary sinus after 3 hours of occlusion and 2 hours of reperfusion of the left anterior descending coronary artery. Myocardial distribution of the cardioplegic solution was measured by computer planimetry in the normally perfused zone, in the ischemic area and in the necrotic zone. RESULTS: The mean (and standard deviation) area at risk of ischemia (% of the left ventricle) delimited by Evans blue perfusion was smaller in dogs receiving a retrograde injection than in those receiving an antegrade injection (34% [3%] v. 42% [4%], p = 0.15). The infarct size (% of the area at risk indicated by triphenyltetrazolium dye) averaged 25% (11%) and 20% (7%) respectively (p = 0.36). The ratio of thallium-201 activity in ischemic to normal myocardium averaged 76% (13%) in the retrograde and 89 (12%) in the antegrade groups (p = 0.75). The ratio of thallium activity of infarct to normal myocardium averaged 56% (8%) in the retrograde group and 93% (19%) in the antegrade group (p = 0.18). Large areas of hypoactivity in the left ventricular myocardium were noted on scintigraphic imaging in all dogs that received retrograde perfusion. CONCLUSIONS: The retrograde injection of cardioplegia through the coronary sinus does not improve the distribution of cardioplegic solution in the acutely ischemic myocardial area nor in the zone of acute infarction in the dog. Because some cells may remain viable in the border zone and into the necrotic area, retrograde cardioplegia may result in suboptimal protection and incomplete prevention of further damage to the myocardium.