Comprehensive, comparative evaluation of 25 automated SARS-CoV-2 serology assays

IMPORTANCE

We have previously highlighted the fact that hundreds of SARS-CoV-2 serology tests were released months after the onset of the COVID-19 pandemic. Of the hundreds of studies investigating the test kits' performance, few were comparative reports, using the same comprehensive sample set across multiple tests. Recently, we reported a comparative assessment of 35 rapid diagnostic tests (RDTs) or microtiter plate enzyme immunoassays (EIA) for use in low- and middle-income countries, using a large sample set from individuals with a history of COVID-19. Only a few tests meet WHO Target Product Profile performance requirements. This study reports on the performance of a further 25 automated SARS-CoV-2 immunoassays using the same panel of samples. The results highlight the better analytical and clinical performance of automated serology test kits compared with RDTs, and the importance of independent comparative assessments to inform the use and procurement of these tests for both diagnostic and epidemiological investigations.

[Preliminary study of PPARA regulate the ferroptosis of hepatocellular carcinoma to prevent disease deterioration]

To explore whether PPARA is involved in the process of ferroptosis in hepatoma cells, peroxisome proliferator activated receptor (PPARA) was comprehensively analyzed in hepatocellular carcinoma (HCC) through public database and experimental data, including the expression, the functions and the potential roles of tumor progression. The research design is experimental research,data analysis based on bioinformatics and cell experiment. From January 2022 to August 2022, relevant cell experiments were conducted in the Basic Medical Laboratory of the General Hospital of the Southern Theatre of the Chinese People's Liberation Army. The expression and the correlation with clinicopathologic features of PPARA in HCC were analyzed by The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. To study the protein expression of PPARA in HCC and normal tissues through the Human Protein Atlas (HPA). The protein-protein interaction (PPI) network between PPARA and the core factor of ferroptosis was constructed based on Search Tool for the Retrival of Interacting Genes/Protein (STRING) database, then, the correlation between PPARA and the core gene Glutamate-cysteine Ligase Catalytic Subunit (GCLC) was analyzed by Gene Expression Profiling Interactive Analysis (GEPIA). Assessed the expression of PPARA in HCC cell lines SK-HEP-1, SMMC-7721, MHCC-97H, BEL-7402 and normal liver cell L02 by Western Blot (WB) and the changes of PPARA expression after 48h treatment with ferroptosis inducer Erastin were observed. Single factor analysis of variance was used to compare the expression of PPARA between groups in GEPIA database. The expression of PPARA in GSE25097 and GSE112790 data was compared by rank sum test. Survival analysis was performed using time series test method. The difference of PPARA expression between clinical and pathological features was compared using the Kruskal-Wallis test. The correlation between the expression of GCLC and PPARA was compared by the method of Spearman correlation. The expression of PPARA in cell lines was compared by paired T test. The results showed that the RNA and protein expression of PPARA in HCC was lower than that in normal tissues (P<0.05). PPARA alterations were correlated with patient clinicopathological features and prognosis (P<0.05). The PPI constructed by STRING database suggests that PPARA interact with the key factors of ferroptosis, such as NFE2 like bZIP transcription factor 2 (NFE2L2), Heme Oxygenase 1 (HMOX1), Tumor Protein P53 (TP53), GCLC, Dipeptidyl Peptidase 4 (DPP4), Citrate Synthase (CS), Arachidonate 15-Lipoxygenase (ALOX15) and Acyl-CoA Synthetase Long Chain Family Member 4 (ACSL4). Furthermore, the PPARA was significantly associated with GCLC validated via GEPIA database(R=0.6, P<0.05). The expression of PPARA increased after treatment with ferroptosis inducer Erastin for 48 h by WB. In conclusion, the expression of PPARA is lower in HCC with a poor prognosis. PPARA interacts with GCLC in regulating ferroptosis in HCC.

Association between one-year exposure to air pollution and the prevalence of pulmonary nodules in China

BACKGROUND

PM2.5 is a well-known airborne hazard to cause various diseases. Evidence suggests that air pollution exposure contributes to the occurrence of pulmonary nodules. Pulmonary nodules detected on the CT scans can be malignant or progress to malignant during follow-up. But the evidence of the association between PM2.5 exposure and pulmonary nodules was limited. &#xD;Objective: To examine potential associations of exposures to PM2.5 and its major chemical constituents with the prevalence of pulmonary nodules.&#xD;Methods: 16865 participants were investigated from eight physical examination centers in China from 2014 to 2017. The daily concentrations of PM2.5 and its five components were estimated by high-resolution and high-quality spatiotemporal datasets of ground-level air pollutants in China. The logistic regression and the quantile-based g-computation models were used to assess the single and mixture impact of air pollutant PM2.5 and its components on the risk of pulmonary nodules, respectively. &#xD;Results: Each 1mg/m3 increase in PM2.5 (OR 1.011 (95%CI: 1.007-1.014)) was positively associated with pulmonary nodules. Among five PM2.5 components, in single-pollutant effect models, every 1 μg/m3 increase in OM, BC, and NO3- elevated the risk of pulmonary nodule prevalence by 1.040 (95%CI: 1.025-1.055), 1.314 (95%CI: 1.209-1.407) and 1.021 (95%CI: 1.007-1.035) fold, respectively. In mixture-pollutant effect models, the joint effect of every quintile increase in PM2.5 components was 1.076 (95%CI: 1.023-1.133) fold. Notably, NO3- BC and OM contributed higher risks of pulmonary nodules than other PM2.5 components. And the NO3- particles were identified to have the highest contribution. The impacts of PM2.5 components on pulmonary nodules were consistent across gender and age.&#xD;Conclusion: These findings provide important evidence for the positive correlation between exposure to PM2.5 and pulmonary nodules in China and identify that NO3- particles have the highest contribution to the risk.&#xD.

[Clinicopathological characteristics of myxoid solitary fibrous tumor: analysis of seven cases]

Objective: To investigate the clinicopathological characteristics, immunophenotypes, and diagnostic and differential diagnostic features of myxoid solitary fibrous tumor (SFT). Methods: Seven cases of myxoid SFT were collected from the archives of Zhejiang Provincial People's Hospital from January 2014 to December 2019. The clinical features, histomorphology, immunohistochemistry, molecular genetics and prognosis were analyzed and the relevant literature was reviewed. Results: There were three male and four female patients ranging from 32 to 67 years. Locations included the pleura (three cases), pelvic cavity, vagina, parotid gland, and nasal cavity(one each). Tumor size ranged from 2.7 to 13.5 cm. Histologically, all cases were characterized predominantly by the presence of myxoid stroma comprising 55% to 90% of the tumor (mean 72%). The tumors were composed of predominantly stellated, spindled or ovoid cells disposed haphazardly, in loose fascicles, or in anastomosing strands imparting a microcystic/reticular appearance in a extensively myxoid, richly vascularized stroma. Staghorn-shaped branching vessels and thin strands of collagen were commonly seen between tumors cells amidst the myxoid background. These myxoid areas were punctuated by small cellular areas showing diagnostic features of classical SFT, which were present in all seven cases. Areas showing giant cell angifibroma-like change were noted in 2 cases and focal lipomatous metaplasia was identified in 1 case. Atypical features suggestive of aggressive behavior were present in 2 cases and in one of the cases myxoid SFT with high-grade sarcomatous overgrowth was noted. Immunohistochemically, tumor cells in all cases stained positively for STAT6 and CD34. Polymerase chain reaction technique showed in both the examined cases the characteristic NAB2ex4-STAT6ex2 fusion gene. According to the Demicco's risk assessment model, four cases were classfied as low, one was classified as moderate and 2 was classified as high. Follow-up information was obtained in 4 cases. One tumor recurred 3 times within 48 months after operation, and the other 3 cases had no tumor recurrence and metastasis. Conclusions: Myxoid SFT represents a rare morphologic variant of SFT with biological behaviors ranging from indolent to aggressive. Myxoid SFT should be included in the differential diagnostic spectrums of soft tissue tumors with significantly myxoid change. Carefully searching for the typical SFT histomorphology with the use of immunohistochemistry and if necessary, molecularly testing for NAB2-STAT6 fusion can help to distinguish myxoid SFT from its many mimickers.

[Diagnosis and therapeutic strategies for hepatopulmonary syndrome]

Hepatopulmonary syndrome (HPS) is a common pulmonary complication in patients with liver disease and / or portal hypertension, and is characterized by abnormal arterial oxygenation caused by intrapulmonary vascular dilatation. The pathogenesis of HPS is complex, with a low clinical early diagnosis rate and poor prognosis. HPS currently lacks effective therapeutic drugs; therefore, liver transplantation is the only fundamental treatment. This article summarizes the pathogenesis, clinical manifestations, diagnosis and treatment of HPS in order to further improve the level of clinical screening and diagnosis and treatment of HPS.

Low pretreatment PNI correlates with worse survival in patients with stage III/IV NSCLC who received chemotherapy

The aim of this study was to investigate the prognostic value of the prognostic nutritional index (PNI) on the long-term survival of non-small cell lung cancer (NSCLC) patients who received platinum-based chemotherapy. Data on nutritional parameters and clinicopathological characteristics [e.g., albumin, total protein, body mass index (BMI), eastern cooperative oncology group (ECOG) performance status, stage, pathology, treatment strategy] were analyzed and retrospectively correlated with overall survival (OS). The PNI was calculated based on the concentration of albumin and lymphocyte count [10 × albumin, (g/dl) + 0.005 × lymphocyte (count/mm3)]. A receiver operating characteristic curve (ROC) analysis was used to find the optimal cut-off value of PNI. Univariate and multivariate analyses were used to evaluate the prognostic value of PNI. A total of 186 patients met the inclusion criteria. The optimal cut-off value for PNI was 50.45. Compared with the parameters of the low PNI group (n=76), high PNI was significantly associated with adenocarcinoma type, stage III, better ECOG and comprehensive treatment modality. The univariate analysis demonstrated that OS was superior when PNI ≥50.45, albumin ≥35 g/l, platelet-lymphocyte ratio (PLR) ≥163 and ECOG <2, and when the patient received a comprehensive treatment modality. In the multivariate analysis, PNI, TNM stage and treatment strategy were identified as independent predictors of survival in this study. This retrospective study demonstrated that a low PNI was related to worse overall survival in patients with stage III/IV NSCLC who received platinum-based chemotherapy. These data provided a conceptual basis for further research on the clinical application of the PNI index for patients receiving chemotherapy for intermediate- and advanced-stage NSCLC.

[Diagnostic value of serum cystatin C for acute kidney injury in patients with liver cirrhosis]

Objective: To determine the diagnostic value of serum cystatin C (Cys C) for acute kidney injury (AKI) in patients with liver cirrhosis. Methods: Serum Cys C levels in 150 liver cirrhosis patients (88 AKI and 62 non-AKI patients) were measured by the Particle-Enhanced Nephelometric Immuno-Assay. The accuracy of serum Cys C for the diagnosis of AKI in liver cirrhosis was evaluated by the ROC curve. Results: Liver cirrhosis patients with AKI had significantly higher serum Cys C levels [2.37 (1.75-2.83) mg/L] than those without AKI [0.97 (0.85-1.09) g/L] (P <0.001). Serum Cys C level was highest in the acute tubular necrosis group [5.41 (2.77-6.19) mg/L], followed by the hepatorenal syndrome group [2.55 (2.28-3.59) mg/L] and prerenal azotemia group [2.07 (1.70-2.41) mg/L], and the serum Cys C level was significantly different between the three groups (P <0.001). In addition, patients with AKI were further divided into infection group and non-infection group. Serum Cys C level was significantly higher in the infection group than in the non-infection group (P <0.05). The area under the ROC curve of serum Cys C for the diagnosis of AKI in liver cirrhosis was 0.99 (0.98-1.00) at a cut-off value of 1.36 mg/L, and the sensitivity and specificity were 97% and 95%, respectively. Conclusion: Serum Cys C is a good marker for detecting AKI in liver cirrhosis, and the different levels of increase in Cys C may be useful in differentiating the different types of AKI.

[Studies on telomerase reverse transcriptase components and liver cancer]

Telomeres are DNA tandem repeats at the ends of chromosomes in eukaryotic cells and play important roles in maintaining the stability and integrity of chromosomes. Telomeres are gradually shortened with cell proliferation, and when they are shortened to a certain length, the cells experience senescence and apoptosis. However, a small number of cells can maintain the length of telomeres and restore their function through related mechanisms (activation of telomerase or other mechanisms), and some cells may even be immortalized. Therefore, telomere and telomerase are thought to be closely associated with tumor development and progression. It has been confirmed that telomerase activation is an early event in the development of primary liver cancer, especially the important component of telomerase telomerase reverse transcriptase (TERT), which plays an important role in this process. Here this article reviews the latest research advances in the function and regulation mechanisms of telomerase and the role of TERT in the development, progression, and treatment of primary liver cancer, especially hepatocellular carcinoma, so as to provide a molecular genetic basis for intervention of liver cancer and related targeted therapy.

A framework radiation hybrid map of buffalo chromosome 1 ordering scaffolds from buffalo genome sequence assembly

River buffalo chromosome 1 (BBU1) is a sub-metacentric chromosome homologous to bovine chromosomes 1 and 27. In this study, we constructed a new framework radiation hybrid (RH) map from BBU1 using BBURH5000 panel adding nine new genes (ADRB3, ATP2C1, COPB2, CRYGS, P2RY1, SLC5A3, SLC20A2, SST, and ZDHHC2) and one microsatellite (CSSM043) to the set of markers previously mapped on BBU1. The new framework RH map of BBU1 contained 141 markers (55 genes, 2 ESTs, 10 microsatellites, and 74 SNPs) distributed within one linkage group spanning 2832.62 centirays. Comparison of the RH map to sequences from bovine chromosomes 1 and 27 revealed an inversion close to the telomeric region. In addition, we ordered a set of 34 scaffolds from the buffalo genome assembly UMD_CASPUR_WB_2.0. The RH map could provide a valuable tool to order scaffolds from the buffalo genome sequence, contributing to its annotation.

Relaxin inhibits cardiac fibrosis and endothelial-mesenchymal transition via the Notch pathway

BACKGROUND

Relaxin (RLX) can prevent cardiac fibrosis. We aimed to investigate the possible mechanism and signal transduction pathway of RLX inhibiting cardiac fibrosis.

METHODS

Isoproterenol (5 mg·kg(-1)·d(-1)) was used to establish the cardiac fibrosis model in rats, which were administered RLX. The cardiac function, related targets of cardiac fibrosis, and endothelial-mesenchymal transition (EndMT) were measured. Transforming growth factor β (TGF-β) was used to induce EndMT in human umbilical vein endothelial cells, which were pretreated with RLX, 200 ng·mL(-1), then with the inhibitor of Notch. Transwell cell migration was used to evaluate cell migration. CD31 and vimentin content was determined by immunofluorescence staining and Western blot analysis. Notch protein level was examined by Western blot analysis.

RESULTS

RLX improved cardiac function in rats with cardiac fibrosis; it reduced the content of collagen I and III, increased the microvascular density of the myocardium, and suppressed the EndMT in heart tissue. In vitro, RLX decreased the mobility of human umbilical vein endothelial cells induced by TGF-β, increased the expression of endothelial CD31, and decreased vimentin content. Compared to TGF-β and RLX co-culture alone, TGF-β + RLX + Notch inhibitor increased cell mobility and the EndMT, but decreased the levels of Notch-1, HES-1, and Jagged-1 proteins.

CONCLUSION

RLX may inhibit the cardiac fibrosis via EndMT by Notch-mediated signaling.

Microsatellite variation in the equine MHC

Genes within the major histocompatibility complex (MHC) encode proteins involved in innate and adaptive immune responses. Genetic variation in this region can influence the immune response of an individual animal to challenges from a variety of pathogens; however, a complete documentation of genetic variation in the MHC is lacking for most domestic animals, including horses. To provide additional genetic markers for study of the horse MHC, or ELA (equine lymphocyte antigen), we identified 37 polymorphic microsatellite repeats in ELA and used these variations separately and together with published SNPs to investigate linkage disequilibrium (LD) and haplotype structure in a sample of Thoroughbred horses. ELA SNPs alone detected little LD, but microsatellites, either separately or combined with SNPs, revealed substantially more LD. A subset of markers in very high LD across the breadth of ELA may be predictive of structural polymorphisms or linked epistases that are important drivers of haplotype structure in Thoroughbreds.

Host selection and colonization strategies with evidence for a female-produced oviposition attractant in a longhorn beetle

In longhorn beetles and many other internally feeding insects, oviposition choice by females is critical to the survival of their offspring because their larvae are incapable of moving between hosts. Here we report on the complex host selection and colonization strategies of a longhorn beetle, Glenea cantor (F.) (Coleoptera: Cerambycidae), which is an important pest of kapok trees [Bombax ceiba L.=Gossampinus malabaricus (DC.) Merr.] in southern Asia. It attacks weakened trees, eventually killing them. The typical oviposition behavioral sequence in the laboratory includes the following: oviposition site search and recognition using antennae and palpi, oviposition slit preparation with mandibles, turning body direction 180°, egg deposition with the ovipositor, and oviposition wound covering with a jelly-like material from the ovipositor. Bark moisture content significantly increases from the upper to lower sections in kapok trees. In accordance with this variation female adults select the upper section of trees first for oviposition. As infestation continues and the host becomes more weakened, ovipositing females move further down the tree for oviposition. Consequently, the larvae kill the hosts from the top down. We show that the jelly-like material or eggs or both have an olfactory role in attracting females to oviposit nearby. Our findings are important in terms of increasing our understanding of host selection and colonization mechanisms of internally feeding insects, particularly cerambycids, and the development of environmentally friendly pest management measures.

Electrophysiologic effects of civamide (zucapsaicin) on canine cardiac tissue in vivo and in vitro

The cardiac electrophysiologic effects of civamide (zucapsaicin), the cis-isomer of the alkyl vanillylamide, capsaicin, were evaluated in intact dogs and isolated Purkinje fibers. In anesthetized dogs, the mechanism of ventricular tachycardia inducible from 1 to 3 h after coronary artery occlusion was determined by activation mapping. Of 16 dogs studied, nine had ventricular tachycardia of focal endocardial origin; four, a reentrant mechanism; and three had no inducible arrhythmia. Civamide (50 microg/kg) was administered to 10 of 13 dogs that were inducible, but three dogs were used as time controls. Transmural activation times were unaltered by civamide, but mean arterial pressure decreased from 76 +/- 10 to 66 +/- 10 mm Hg (p < 0.05), and muscle refractory periods shortened from 138 +/- 3 to 132 +/- 4 ms (p < 0.05). Civamide altered inducibility in five of six dogs with ventricular tachycardia of focal endocardial origin, but those with epicardial reentrant mechanisms were not affected in three of four dogs. With microelectrode techniques in vitro, civamide (10(-5) M) shortened the action-potential duration at 50% repolarization (APD50) from 193 +/- 13 to 177 +/- 12 ms (p < 0.01) and APD90 from 260 +/- 15 to 248 +/- 13 ms (p < 0.01) in isolated Purkinje fibers (n = 10). Nifedipine prevented the effects of civamide in vitro. These results show that civamide may alter inducibility of ventricular tachycardia with focal endocardial origin and shorten APD of Purkinje fibers in vitro. The effects of civamide in vitro are prevented by preexposure of the Purkinje fibers to nifedipine, suggesting that the electrophysiologic effects of civamide may be mediated through blockade of calcium channels.

Effect of alpha2-adrenoceptor stimulation on isolated canine Purkinje fiber contraction

We have recently identified the presence of postjunctional alpha2-adrenoceptors in canine Purkinje fibers. In this study, we examined the effects of alpha2-adrenoceptor stimulation on the contraction strength of isolated Purkinje fibers. Exposure to the alpha2-adrenoceptor specific agonist and antagonist, UK 14,304 (5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)-6-quinoxalinamine) and yohimbine (17-hydroxyyohimban-16-carboxylic acid methyl ester hydrochloride) alone at 0.1 microM respectively, did not produce any significant effect on Purkinje contraction strength. Purkinje contraction strength was augmented by isoproterenol (0.1 microM), forskolin (0.1 microM), or 8-bromo-adenosine cyclic 2',3'-monophosphate (8-bromo-cAMP, 10 microM). UK 14,304 significantly reversed the effects of isoproterenol and forskolin but not those of 8-bromo-cAMP on Purkinje contraction strength. After incubation with pertussis toxin, the positive inotropic effect of forskolin on Purkinje contraction strength remained intact, but the forskolin effect could no longer be reversed by UK 14,304. These results suggest that the postjunctional alpha2-adrenoceptors in canine Purkinje fibers are coupled to a pertussis toxin-sensitive G protein, probably Gi. Stimulation of the alpha2-adrenoceptor antagonizes the effect of beta-adrenoceptor stimulation on Purkinje contraction strength in an accentuated antagonism manner.

Cyclic AMP-dependent phosphodiesterase isozyme-specific potentiation by protein kinase C in hypertrophic cardiomyopathic hamster hearts

We recently reported that protein kinase C (PKC) potentiates cAMP-dependent phosphodiesterase (PDE) activity in Syrian hamster hearts with hypertrophic cardiomyopathy (HCM) but not in control hamster hearts. In this study, we examined the mechanism of this PKC/PDE interaction by identifying the PDE isozyme that is the target of PKC modulation. Using Mono-Q high performance liquid chromatography, both control and HCM hamster cardiac PDE could be partially purified into the calcium/calmodulin-dependent (I), the cGMP-stimulated (II), and the low KM (III) isozyme fractions. The elution profiles of PDE isozyme fractions were similar to those in isolated hamster cardiac myocytes. The percentages of PDE isozymes activities (I/II/III) were 68.8:22.4:8.8% and 51.1:38.4:10.5% for HCM and control hearts, respectively (n = 4), suggesting a change in the quantitative expression of isozymes activities in HCM hearts with a significant increase in the calcium/calmodulin-dependent PDE isozyme activities (p < 0.05 compared with control). The addition of exogenous PKC (100 munits of rat brain) produced a 60% stimulation in the calcium/calmodulin-dependent PDE isozyme fraction but not in other PDE isozymes of HCM and in none of the isozymes in control hearts. This PKC-mediated potentiation of the calcium/calmodulin-dependent PDE activity was completely blocked by the PKC-specific peptide inhibitor PKC(19-31). Analysis of enzymatic kinetics showed that PKC enhanced the calcium/calmodulin-dependent PDE isozyme activity in HCM by increasing its Vmax (from 350 pmol/mg/min at baseline to 758 pmol/min/mg with PKC) without changing its KM (0.69 microM at baseline versus 0.89 microM with PKC). These results suggest that there are both quantitative and qualitative abnormalities in the expression of the calcium/ calmodulin-dependent PDE isozyme in HCM hearts and that the PKC modulation of PDE activity in the HCM heart is isozyme specific.

Mechanism of alpha-2 adrenergic modulation of canine cardiac Purkinje action potential

We reported recently that stimulation of postjunctional alpha-2 adrenergic receptors prolongs the action potential durations (APD) of isolated canine Purkinje fibers. With standard microelectrode techniques, we examined the ionic mechanism through which alpha-2 adrenergic stimulation prolonged Purkinje APD, by measuring the effects of inhibitors of the various plateau currents on the alpha-2-mediated prolongation of APD. The alpha-2-specific agonist UK 14,304 (0.1 microM) prolonged the Purkinje APD at 50% repolarization and the APD at 90% repolarization, and these effects were inhibited by yohimbine (0.1 microM). The Purkinje APD at 50% repolarization and the APD at 90% repolarization were prolonged significantly with the transient outward potassium current inhibitor 4-aminopyridine (1 mM), the rapid component of delayed rectifier potassium current inhibitor d-sotalol (10 microM), the slow component of delayed rectifier potassium current inhibitor indapamide (0.1 microM) and the chloride current inhibitor mefenamic acid (10 nM) and were shortened significantly with the calcium current inhibitor nifedipine (0.3 microM). Prolongation of Purkinje APD at 50% repolarization and APD at 90% repolarization by UK 14,304 remained intact in the presence of d-sotalol, indapamide, mefenamic acid and nifedipine. All of these UK 14,304 effects were significantly reversed by yohimbine. Only in the presence of 4-aminopyridine did UK 14,304 fail to prolong Purkinje APD. The phase 1 magnitudes of Purkinje action potentials were also significantly inhibited by UK 14,304. This effect was completely abolished only in the presence of 4-aminopyridine. These results suggest that inhibition of the 4-aminopyridine-sensitive transient outward potassium current is the major ionic mechanism by which alpha-2 adrenergic stimulation prolongs Purkinje APD.

alpha 2-Adrenergic receptor binding in canine Purkinje fibers

Autoradiograms were developed from free running strands of Purkinje fibers and from left ventricular myocardium of dog hearts exposed to [7-methoxy-3H]prazosin or [O-methyl-3H]yohimbine in the presence or absence of excessive non-radioactive ligands. Both Purkinje fiber and ventricular myocardium show high density, tissue-specific binding to [3H]prazosin. In contrast, high density, tissue-specific binding to [3H]yohimbine was present in Purkinje fibers but not in ventricular myocardium. Membrane fractions showed high affinity, saturable, and displaceable binding with [3H]yohimbine in preparations from canine cardiac Purkinje fibers but not those from canine cardiac ventricular myocardium. Scatchard analysis of the canine Purkinje membrane alpha 2-adrenergic receptor binding showed a Bmax of 54.9 fmol/mg protein with a Kd of 6.25 nM. These results confirm the electrophysiological findings that post-junctional alpha 2-adrenergic receptors are present in Purkinje fibers.

Protein kinase C isozyme-specific modulation of cyclic AMP-dependent phosphodiesterase in hypertrophic cardiomyopathic hamster hearts

We recently demonstrated that protein kinase C (PKC) activities were elevated in hypertrophic cardiomyopathic (HCM) hamster hearts and that activation of PKC resulted in stimulation of cAMP-dependent phosphodiesterase (PDE) activity. In this study, we determined the composition of PKC isozymes in control and HCM hearts and identified the PKC isozyme responsible for the modulation of PDE activity in HCM hearts. Using quantitative autoradiographic techniques with PKC isozyme-specific antibodies, we found that the PKC alpha, epsilon, and zeta isozymes were expressed in both control and HCM hearts. The immunoreactive amounts of cytosolic PKC alpha and PKC epsilon and of membrane PKC zeta were significantly increased in HCM hearts. The enzymatic activity of PKC in HCM hearts was significantly elevated in both membrane (148.0 +/- 13.7 versus 78.9 +/- 1.9 pmol/mg/min in controls, four experiments) and cytosol (117.3 +/- 5.1 versus 75.7 +/- 5.1 pmol/mg/min in controls, four experiments). Contribution of individual PKC isozyme activity was assessed by the immunoprecipitable PKC activity with isozyme-specific antibodies. The membrane PKC epsilon (41.7 +/- 4.9 versus 18.7 +/- 0.3 pmol/mg/min in controls, four experiments, p < 0.05) and PKC zeta (61.5 +/- 14.0 versus 20.3 +/- 2.7 pmol/mg/min in controls, four experiments, p < 0.05) but not PKC alpha (50.9 +/- 6.8 versus 44.3 +/- 1.5 pmol/mg/min, four experiments, p = N.S.) were increased in HCM hearts. On the other hand, the cytosolic PKC alpha (47.7 +/- 4.1 versus 27.0 +/- 1.4 pmol/mg/min, four experiments, p < 0.05) and PKC epsilon (42.8 +/- 3.1 versus 19.1 +/- 3.9 pmol/mg/min, four experiments, p < 0.05) but not PKC zeta (27.2 +/- 3.0 versus 32.0 +/- 2.1, four experiments, p = N.S.) were increased in HCM hearts. Furthermore, after immunoprecipitation of PKC alpha, activation of PKC could no longer potentiate the PDE activity in HCM hearts. Removal of PKC epsilon or PKC zeta, on the other hand, did not affect the PKC-mediated PDE stimulation in HCM hearts. These results suggest that there is an increase in the quantitative expression of PKC isozymes in HCM hearts and that the cross-talk between PKC and PDE in these hearts is mediated specifically via the PKC alpha isozyme.

Correction of corrected transposition of the great arteries associated with cardiac anomalies

Reported in this paper are 8 cases of corrected transposition of the great arteries associated with anomalies. All the patients underwent the repair of the ventricular septal defect and atrial septal defect, the replacement of left-side tricuspid value, the pulmonary valvotomy and the placement of extra-cardiac conduit to the pulmonary trunk respectively with no hospital death after operation. The paper also described the selection of the heart incision, the prevention of injury of the conduction system and indication of the placement of extra-cardiac conduit.

Electrophysiological effects of alpha 2-adrenergic stimulation in canine cardiac Purkinje fibers

The effects of alpha 2-adrenergic stimulation on action potentials were measured in isolated canine Purkinje fibers. Action potential durations at 50 and 90% of repolarization (APD50 and APD90) were significantly prolonged by 0.25 microM l-norepinephrine + 0.5 microM dl-propranolol (NE+P) from baseline values of 166 +/- 7 and 249 +/- 9 (SE) ms (n = 7) to 174 +/- 7 and 265 +/- 9 ms, respectively (P < 0.05 for both). Selective alpha 2-blockade with 0.01 microM yohimbine (YO) reduced this prolongation by NE+P in APD50 and APD90 to 169 +/- 7 and 256 +/- 8 ms, respectively (P < 0.05 compared with NE+P). Additional selective alpha 1-blockade with 0.01 microM prazosin (PZ) completely blocked the effects of NE+P, returning APD50 and APD90 to 163 +/- 7 and 250 +/- 9 ms (not different from baseline). After incubation of isolated Purkinje fibers with pertussis toxin (1 microgram/ml), which reduced the availability of a 41-kDa membrane protein for ADP ribosylation by 70 +/- 7% (n = 4, P < 0.05), YO failed to reverse the prolongation in action potential durations brought on by NE+P, but the effects of PZ were intact. The effects of alpha 2-stimulation on beta-adrenergic-induced delayed afterdepolarizations (DADs) were studied by burst pacing of Purkinje fibers in Tyrode solution containing 7.5 mM Ca2+. The DADs induced in the presence of NE+PZ (beta- + alpha 2-stimulation) were significantly smaller in amplitude and required a shorter pacing cycle length to reach threshold than those induced in the presence of NE+PZ+YO (unopposed beta-adrenergic stimulation). Furthermore sustained triggered activity, seen in five of eight preparations under beta-stimulation, could no longer be elicited in the presence of beta- + alpha 2-stimulation. These results suggest that the postjunctional alpha 2-adrenergic receptors in canine Purkinje fibers are coupled to a pertussis toxin-sensitive G protein and that stimulation of these receptors leads to action potential prolongation and suppression of DADs induced by beta-adrenergic stimulation.

The identity of immunosuppressive components of the ethyl acetate extract and chloroform methanol extract (T2) of Tripterygium wilfordii Hook. F

A variety of preparations of Tripterygium wilfordii Hook.F (TWHF) have been reported to be effective in the treatment of autoimmune diseases, including a chloroform methanol extract termed T2 and an ethyl acetate (EA) extract. The immunosuppressive activity of the EA extract was analyzed and the components accounting for this effect determined and compared to those of T2. More than 0.25 microgram/ml of the EA extract inhibited antigen- and mitogen-stimulated human T cell proliferation. The inhibitory effect of the EA extract on T cell proliferation resulted largely from suppression of interleukin-2 production. At concentrations that inhibited T cell function, the EA extract also profoundly suppressed [3H]-thymidine incorporation by mitogen-stimulated B cells, but it did not inhibit antigen presentation by monocytes and only modestly affected interleukin-6 production by lipopolysaccharide-stimulated monocytes. The profile of inhibition was comparable to that previously reported for the chloroform-methanol extract of Tripterygium wilfordii Hook.F, T2. To delineate the components of these extracts that might account for their immunosuppressive effect, we analyzed the composition of diterpenoid compounds. Both extracts contained triptolide and tripdiolide as the major immunosuppressive diterpenoids, but at different concentrations. Comparison of the composition of these extracts and the inhibitory capacity of the purified components indicated that the triptolide concentration of the EA extract can account for its immunosuppressive activity, although the combination of both triptolide and tripdiolide or other unknown components may be necessary to explain the inhibitory effects of T2.

Effect of protein kinase C on cyclic 3',5'-adenosine monophosphate-dependent phosphodiesterase in hypertrophic cardiomyopathic hamster hearts

"Cross-talk," or interaction between different signal transduction pathways, is known to exist in noncardiac cells, but it has not been demonstrated previously in mammalian hearts. We found that hypertrophic cardiomyopathic Syrian hamster (BIO 14.6, 6 months old) hearts were deficient in cyclic 3',5'-adenosine monophosphate (cAMP) [11.9 +/- 0.4 vs. 15.4 +/- 0.4 pmol/mg protein in age-matched control hamsters (BIO RB), n = 6, P = .0005] but not in cyclic 3',5'-guanosine monophosphate (1.23 +/- 0.10 vs. 1.34 +/- 0.18 pmol/mg protein in BIO RB, n = 6, P = N.S.). The reduction in cAMP was at least partly accounted for by an increase in the cytosolic phosphodiesterase (PDE) activity in BIO 14.6 hearts (1709 +/- 119 vs. 1341 +/- 113 pmol/min/mg protein in age-matched BIO RBs, n = 12, P = .006), suggesting that there is an increase in cAMP turnover in BIO 14.6 hearts. Protein kinase C (PKC) activities were also significantly elevated in BIO 14.6 hearts (77.9 +/- 2.1 vs. 54.6 +/- 3.3 pmol/min/mg protein in BIO RBs, n = 6, P < .001). Activation of PKC by phorbol 12-myristate 13-acetate (PMA, 10 microM) produced significant potentiation in PDE activities in BIO 14.6 but not in BIO RB hearts, and the PMA-induced increase in PDE activity could be blocked by the PKC-specific pseudosubstrate inhibitor peptide PKC(19-31).(ABSTRACT TRUNCATED AT 250 WORDS)

[The relation between p53 expression and lymph node metastasis of breast cancer]

The monoclonal antibody to p53 and a rapid immunohistochemical method were used in this study to detect p53 expression in 50 paraffin-embedded breast cancers and 7 benign hyperplastic diseases of breast. The results of immunostaining showed that 12 (24%) cases of breast cancers were positive and all benign lesions were negative. No significant difference was found between primary and metastatic sites of 11 paired samples of breast cancers in p53 expression, suggesting that the abnormal expression of had p53 occurred before lymph node metastasis of breast cancer. Statistical analysis revealed that the abnormal expression of p53 was significantly correlated with lymph node metastasis of breast cancer (P < 0.005) and also correlated with medullary breast cancer in which two of four cases strongly positive to p53 had lymph node metastasis. Our results indicate that the abnormal expression of p53 is not only involved in the development, but also involved in the metastasis of breast cancer. Therefore, detection of p53 expression may have significant clinical importance in the evaluation of the tendency of lymphatic metastasis of breast cancer.

[Histological study on repairing experimental pulp chamber floor perforations with yunnan bai-yao in dog]

Yunnan Baiyao (YNBY), amalgam, hydroxylapatite and calcium hydroxide were used separately in repairing the experimental pulp chamber floor perforation (PCFP) of dog teeth. The animals were killed at the time of 1, 4, 8 and 12 weeks after experiment. The experimental teeth with periapical tissue were removed and observed their histological changes by optical microscope. The effects that different materials in repairing the tissue of PCFP were observed. Twenty teeth were taken from every dog, each group contained four teeth, the others were used for control group.

RESULTS

In initial period (1st, 4th week) inflammatory infiltration was present in PCFP of every group, but the group with YNBY was milder. Pyogenic foci were present in the hydroxylapatite and calcium hydroxide groups. In late stage of experiment (8th and 12th week) inflammatory reactions of each group were alleviated except control group. Epithelial metaplasia and cicatritation were found in the vicinity of perforated area. Dentin cementum and alveolar bone were absorbed in majority of experimental group. It was also observed in the group with YNBY. But in late stage similar cementum formation and alveolar bone neogenesis were found in the perforated area around the repairing materials. It revealed that hemostasis, Promoting Blood Circulation to Remove Stasis and antiphlogistic actions were advantageous to the inflammation, control and repair course of the PCFP. The article discussed that YNBY might promote the repairing of cementum and alveolar bone of perforated area.

Effect of cardiopulmonary bypass on the specific immunity of the host

T cell subsets and immunoglobulin (Ig) were observed sequentially with the OKT monoclonal antibodies rosette test and the rate scattering turbidimetry in 13 patients who underwent open heart surgery under cardiopulmonary bypass (CPB) for rheumatic heart diseases (RHD) and congenital heart diseases (CHD), before and after operation. Compared with preoperative values, in the early period after CPB, T helper cells, T helper cells to T suppressor cells ratio and IgG decreased significantly; whereas T suppressor cells increased, in RHD and CHD. The T cell subsets returned to the preoperative levels two weeks after CPB in RHD and CHD. The IgG came back to the preoperative levels two weeks after CPB in RHD and only one week after CPB in CHD.

Developmental changes of protein kinase C and Gs alpha in hypertrophic cardiomyopathic hamster hearts

Protein kinase C (PKC) and GTP-binding proteins (G-proteins) are known to be major determinants in the modulation of cardiac function. In this study, we examined the developmental changes of PKC and the alpha-subunit of the stimulatory guanosine triphosphate binding protein (Gs alpha) in hypertrophic cardiomyopathic Syrian hamster (BIO 14.6) hearts, before the onset of hypertrophy (30 days old) and at the peak of hypertrophy (6 months old) and compared these with age-matched control hamster (BIO RB) hearts. At 30 days, cardiac PKC activity was similar between BIO 14.6 and BIO RB both in the membrane (117.1 +/- 9.9 pmol/min/mg vs 131.2 +/- 12.7 pmol/min/mg in controls, n = 8) and in the cytosolic fractions (213.1 +/- 22.0 pmol/min/mg vs 186.6 +/- 23.9 pmol/min/mg in controls, n = 9). At 6 months, PKC activity was significantly higher in BIO 14.6 than in controls, both in the cardiac membrane (131.9 +/- 7.1 pmol/min/mg vs 40.7 +/- 4.7 pmol/min/mg in controls, n = 8, p < 0.00001) and cytosol (77.9 +/- 2.1 pmol/min/mg vs 54.6 +/- 3.3 pmol/min/mg in controls, n = 6, p < 0.0005). In BIO RB hearts, membrane and cytosolic PKC activities were significantly reduced at 6 months compared with those at 30 days of age (p < 0.001). However, the membrane PKC activity in 6-month-old BIO 14.6 was maintained at the level of the 30-day-old hearts. On the other hand, the relative immunoreactive amounts of Gs alpha were similar between BIO RB and BIO 14.6 hearts at 30 days and at 6 months of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Solubilization and characterization of a guanine nucleotide-sensitive form of the calcitonin gene-related peptide receptor

Calcitonin gene-related peptide (CGRP) receptors were solubilized from rat cerebellum membranes in an active, stable, and guanine nucleotide-sensitive form by using digitonin. Nearly 90% of membrane CGRP receptors and 50% of membrane protein were solubilized by digitonin treatment of cerebellum membranes. Binding of 125ICGRP to soluble receptors was specific, saturable, of high affinity, and reversible. Scatchard analysis of the saturation binding data revealed a homogeneous population of binding sites with a Kd of 178 +/- 42 pM and a Bmax of 201 +/- 17 fmol/mg of protein. Binding of 125ICGRP to soluble receptors was inhibited nearly 60% by guanosine-5'-O-(3-thio)triphosphate (GTP gamma S) (100 microM), suggesting coupling of receptors with guanine nucleotide-binding proteins (G proteins) to form high affinity binding sites. Antiserum against the amino-terminal region of Gs alpha immunoprecipitated a significant portion of soluble CGRP receptors, indicating association of receptors with Gs alpha. In agreement with the saturation binding data, association kinetic studies with soluble receptors indicated binding of 125ICGRP to a single population of sites. Dissociation kinetic data, in contrast, demonstrated that 125ICGRP dissociated from labeled receptors with fast- and slow-dissociating components. GTP gamma S significantly accelerated dissociation of 125ICGRP from labeled receptors; however, dissociation still occurred from two distinct affinity components, with rate constants significantly different from those observed in the absence of GTP gamma S. These observations suggest that soluble CGRP receptors, like native membrane-bound receptors, exist in two distinct affinity states in both G protein-coupled and -uncoupled receptor states. Soluble receptors were retained specifically on a wheat germ lectin column, and affinity cross-linking of receptors specifically labeled with 125ICGRP demonstrated labeling of a 67-kDa protein, suggesting that the rat cerebellum CGRP receptor is a 67-kDa glycoprotein. This study is the first to report solubilization of CGRP receptors retaining the native ability of the receptor to undergo functional coupling with G proteins and to provide direct evidence for association of these receptors with Gs alpha.

[Effect of vitamin D over-dosage on the tooth and bone development of rabbits]

The paper investigated the changes of rabbit's tooth and jaw tissues by vitamin-D poisoning experiment. The results showed the dentin, periodontium, jaw bone and long bone of rabbit were all changed. X-ray showed subperiosteum absorbation and periosteum reaction. The mineral content of the rabbit's epiphysis and long bone diaphysis in experiment group were lower than that of control group. The histopathological findings were irregular hyperplasia of dentin, arrange disturbance of periodontal fibers, absorbation of the alveolar bone and mal-ossification of long bones. The above changes were more significant during 30-45 days of rabbit poisoning, after 60 days of poisoning the above signs were gradually released.

[The effect of irradiation using a linear accelerator on the dentognathic system of white rats]

The LMR-15c linear accelerator was used to irradiate the maxillofacial region of white rats. The results showed that when the irradiation dose reached 3,000 rad (TDF49), changes in pulpal tissue, periodontal tissue, parotid and submandibular gland, lymph nodes and oral mucosa began to take place and became severe as the times of irradiation and the cumulated doses increased. The body weight of rats had no obvious changes after irradiation, however, blood changes and during the recovery period showed that the injury of irradiation to immune function was obvious. The biological effects of X-rays, 60 Cobalt and linear accelerator were compared. The irradiation damage to the surface of oral tissues was milder in the latter, and no change could be found in jaw bones. It was suggested that the linear accelerator is the first choice to be selected for treatment of oral cancers.