Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A

We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at 3.67±0.05±0.15  PeV. Below the knee, the spectral index is found to be -2.7413±0.0004±0.0050, while above the knee, it is -3.128±0.005±0.027, with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of -0.1200±0.0003±0.0341. This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components.

[Anatomical study of the architecture of the cutaneous branch-chained blood vessels in the medial lower leg in adult]

Objective: To investigate the architecture of the cutaneous branch-chained blood vessels in the medial lower leg and provide the anatomical basis for design and clinical application of the cutaneous branch-chained flap from this region. Methods: The experimental research method was used. From March to May 2023, the anatomical study was conducted on the 5 voluntarily donated fresh adult (aged 50 to 70 years, all male) cadaveric specimens from Hangzhou Normal University School of Basic Medical Sciences. The fine anatomy under microscope was performed on each lower leg specimens of 5 corpses (1 lower leg specimen was conducted with digital radiography (DR) scan before fine anatomy), to observe, measure, and record the course of posterior tibial artery, quantity of perforator, the distance between the perforating point of each perforator and the medial condyle of tibia, the external diameter of posterior tibial artery perforator, the length of perforator pedicle, the horizontal distance between the posterior tibial artery perforator and the saphenous nerve, and the course of each perforator within superficial fascia after crossing the deep fascia and the distribution of the cutaneous branch-chains. The DR scan under the perfusion of barium sulfate was conducted in one lower leg specimen to observe the distribution of cutaneous branch-chained vascular network (hereinafter referred to as vascular chain) between perforators. Transparent skin specimen was made from one leg specimen after anatomy to observe the distribution of perforators and vascular chains between perforators. Results: In 5 lower leg specimens, the upper part of posterior tibial artery was located deep in soleus muscle, and the lower part was located between the medial edge of gastrocnemius muscle and flexor digitorum longus muscle. A total of 28 posterior tibial artery perforators were identified, with an average of 5.6 branches in each lower leg. The distance between the perforating point of perforator and the medial condyle of tibia ranged from 6.5 to 36.0 cm, mainly distributed at 22.0 (15.1, 28.1) cm from the medial condyle of tibia, in zones 3 to 6. The external diameters of perforators of posterior tibial arteries were 0.7-1.1 mm. The length of perforator pedicle was 1.0-4.5 cm, and the horizontal distance between the posterior tibial artery perforator and the saphenous nerve was 0.5-3.0 cm. The fine anatomy under microscope showed that the posterior tibial artery perforators had long upward and downward branches after crossing the deep fascia, and the ascending branches and descending branches were anastomosed longitudinally to form the nutrient cutaneous branch-chain in the medial lower leg. DR scan and transparent skin specimen both showed that longitudinal vascular chain was formed between the posterior tibial artery perforators, the transparent skin specimen also showed that longitudinal blood vessel chains included the direct connecting vessels in the adipose layer and the indirect connecting vessels in the subdermal layer. Conclusions: The cutaneous branch-chained vessels in the medial lower leg are constructed by posterior tibial artery perforators, direct connecting vessels, indirect connecting vessels, and traffic branches. The cutaneous branch-chained flap is reliable in terms of vascular anatomy, and can carry the saphenous nerve for partial restoration of its sensation, thus it is an ideal flap.

Measurement of Ultra-High-Energy Diffuse Gamma-Ray Emission of the Galactic Plane from 10 TeV to 1 PeV with LHAASO-KM2A

The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this Letter, we report the measurements of diffuse γ rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner (15°10  TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of -2.99±0.04, which is different from the curved spectrum as expected from hadronic interactions between locally measured cosmic rays and the line-of-sight integrated gas content. Furthermore, the measured flux is higher by a factor of ∼3 than the prediction. A similar spectrum with an index of -2.99±0.07 is found in the outer Galaxy region, and the absolute flux for 10≲E≲60  TeV is again higher than the prediction for hadronic cosmic ray interactions. The latitude distributions of the diffuse emission are consistent with the gas distribution, while the longitude distributions show clear deviation from the gas distribution. The LHAASO measurements imply that either additional emission sources exist or cosmic ray intensities have spatial variations.

A tera-electron volt afterglow from a narrow jet in an extremely bright gamma-ray burst

Some gamma-ray bursts (GRBs) have a tera-electron volt (TeV) afterglow, but the early onset of this has not been observed. We report observations with the Large High Altitude Air Shower Observatory of the bright GRB 221009A, which serendipitously occurred within the instrument field of view. More than 64,000 photons >0.2 TeV were detected within the first 3000 seconds. The TeV flux began several minutes after the GRB trigger, then rose to a peak about 10 seconds later. This was followed by a decay phase, which became more rapid ~650 seconds after the peak. We interpret the emission using a model of a relativistic jet with half-opening angle ~0.8°. This is consistent with the core of a structured jet and could explain the high isotropic energy of this GRB.

[Pathological characteristics of colorectal adenoma with submucosal pseudoinvasion]

Objective: To investigate the pathomorphological characteristics of colorectal adenoma with submucosal pseudoinvasion and to summarize the corresponding pseudoinvasion patterns. Methods: The clinicopathological data of 9 cases of colorectal adenoma were collected at 989 Hospital of PLA Joint Logistics Support Force (4 cases) and Beijing Chaoyang Hospital, Capital Medical University (5 cases), from 2016 to 2019. retrospectively, and the histomorphological characteristics and immunophenotypes were analyzed, and discussed in light of the relevant literature. Results: There were 8 cases of adenoma with stalk. Tumor glands were found in the submucosa at the head end of adenoma, similar to infiltrating adenocarcinoma. The structure and cellular morphology of submucosal glands were very similar to the intramucosal tumor while the local submucosal tumor showed continuity with the intramucosal tumor. The submucosal tumors were lobule-like or nest-like with clear boundary. The outline of the gland was smooth and blunt-round, and there was loose fibromyxoid stroma around the gland, similar to the mucosa propria stroma. Some cases of the submucosal glands were cystic dilated with mucocele formation and hemosiderin deposition. One case with broad stalk-base showed an elevated adenoma with local high grade dysplasia involved in the aggregated lymphoid nodule, forming the lymphoglandular complexes, simulating invasive adenocarcinoma with associated submucosal lymphoid aggregates. Submucosal cancer tissue and intramucosal cancer tissue had continuity, and their morphology was the same. The submucosal tumor was round in the outline, smooth and blunt in the edge, and surrounded by lymphoid tissue. There was no stromal response around the gland to promote the proliferation of connective tissue, neither was there single-cell or small-cell cluster, sharp angle branch of gland, or vascular infiltration. Conclusions: There are two unique morphological patterns in colorectal adenoma with submucosal pseudoinvasion. Morphologically, the data show that one is lobular-like pattern, and the other is lymphoglandular complexes-like pattern. The main features of the two patterns are the same-morphology and continuity of submucosal tumor and intramucosal tumor. The pushed glands were surrounded by the intrinsic membrane stroma and muscularis mucosae in proper order, lacking the typical morphological characteristics of invasive adenocarcinoma.

[Clinical feature changes of a COVID-19 patient from mild to critical condition and cardiopulmonary pathological results]

Objective: To analyse the clinical history, laboratory tests and pathological data of a patient who suffered from novel coronavirus pneumonia(COVID-19) and provide reference for the clinical treatment of similar cases. Methods: Data of clinical manifestation, laboratory examination, bronchoscopy, echocardiography and cardiopulmonary pathological results were retrospectively reviewed in a case of COVID-19 with rapid exacerbation from mild to critical condition. Results: This patient hospitalized at day 9 post 2019 novel coronavirus(2019-nCoV) infection, experienced progressive deterioration from mild to severe at day 12, severe to critical at day 18 and underwent extracorporeal membrane oxygenation(ECMO) and continuous renal replacement therapy(CRRT) as well as heart lung transplantation during day 28-45 post infection, and died at the second day post heart and lung transplantation. The patient had suffered from hypertension for 8 years. At the early stage of the disease, his symptoms were mild and the inflammatory indices increased and the lymphocyte count decreased continuously. The patient's condition exacerbated rapidly with multi-organ infections, and eventually developed pulmonary hemorrhage and consolidation, pulmonary hypertension, right heart failure, malignant ventricular arrhythmias, liver dysfunction, etc. His clinical manifestations could not be improved despite viral RNAs test results became negative. The patient underwent lung and heart transplantation and finally died of multi organ failure at the second day post lung and heart transplantation. Pathological examination indicated massive mucus, dark red secretions and blood clots in bronchus. The pathological changes were mainly diffused pulmonary hemorrhagic injuries and necrosis, fibrosis, small vessel disease with cardiac edema and lymphocyte infiltration. Conclusions: The clinical course of severe COVID-19 can exacerbate rapidly from mild to critical with lung, liver and heart injuries.

Photoemission Spectroscopic Evidence for the Dirac Nodal Line in the Monoclinic Semimetal SrAs_{3}

Topological nodal-line semimetals with exotic quantum properties are characterized by symmetry-protected line-contact bulk band crossings in the momentum space. However, in most of identified topological nodal-line compounds, these topological nontrivial nodal lines are enclosed by complicated topological trivial states at the Fermi energy (E_{F}), which would perplex their identification and hinder further applications. Utilizing angle-resolved photoemission spectroscopy and first-principles calculations, we provide compelling evidence for the existence of Dirac nodal-line fermions in the monoclinic semimetal SrAs_{3}, which possesses a simple nodal loop in the vicinity of E_{F} without the distraction from complicated trivial Fermi surfaces. Our calculations revealed that two bands with opposite parities were inverted around Y near E_{F}, resulting in the single nodal loop at the Γ-Y-S plane with a negligible spin-orbit coupling effect. The band crossings were tracked experimentally and the complete nodal loop was identified quantitatively, which provide a critical experimental support for the existence of nodal-line fermions in the CaP_{3} family of materials. Hosting simple topological nontrivial bulk electronic states around E_{F} and without complication from the trivial states, SrAs_{3} is expected to be a potential platform for topological quantum state investigation and applications.

[Trends in Gleason scores of Chinese prostate carcinoma from 1995 to 2014]

OBJECTIVE

To assess the changing trends in Gleason score (GS) of Chinese prostate carcinoma (PCa) from January 1995 to December 2014.

METHODS

In the study, 875 patients admitted to hospital from January 1995 to December 2004 (1995-2004) and from January 2005 to December 2014 (2005-2014) were divided into two groups. The mean levels and proportions of GS, primary and secondary grades were studied. The patients were divided into four groups according to age: <60, 60-69, 70-79 and ≥80 years. Types of specimen included needle biopsy (NB), transurethral resection of the prostate (TURP) and radical prostatectomy (RP). Histological types were made up by acinar carcinoma and other types (including atrophic, pseudohyperplastic, foam, signet ring cell and ductal carcinoma, and so on). The total prostate-specific antigen (tPSA) involved groups of <20.0 μg/L and ≥20.0 μg/L. We observed the mean levels and proportions of GS in age, types of specimen, histological types and total prostate-specific antigen in different periods, and used SPSS 17.0 software for statistical analysis.

RESULTS

Compared with 1995-2004, the mean levels of GS, primary and secondary grades decreased 0.32 (P=0.003), 0.19 (P=0.001) and 0.12 (P=0.016) in 2005-2014, respectively. The proportions of ≤6 in GS increased 10.9% (P=0.003), and ≥8 decreased 14.0% (P<0.001). The difference of GS 7 was not statistically significant. In the primary grade, the ratio of grades≤3 increased 12.8% (P=0.001), and grade 4 decreased 7.4% (P=0.037), grade 5 decreased 5.5% (P=0.007). The ratio of secondary grades ≤3 increased 7.6% (P=0.037). The difference of grades 4 and 5 was not statistically significant.

CONCLUSION

GS in Chinese patients with PCa showed a downward trend, which is one of the notable features in the past 20 years in China. The types of specimen and age are important factors in GS, while the histological types and tPSA have less impact on the GS.

Helicity-dependent photocurrent induced by the in-plane transverse electric current in an InAs quantum well

We report the observation of a new type of helicity-dependent photocurrent induced by an in-plane transverse direct electric current in an InAs quantum well. The amplitude of the photocurrent depends linearly on the transverse current. Moreover, the observed incident azimuth-angle dependence of this photocurrent is different from that induced by the circular photogalvanic effect. This new photocurrent appears as a result of an asymmetrical carrier distribution in both the conduction and valence bands induced by the transverse current. The photoexcited carrier density created by interband transition processes is thus modulated and leads to the observed new azimuth-angle dependence. The observed efficient generation of the helicity-dependent photocurrent offers an effective approach to manipulate electron spins in two-dimensional semiconductor systems with the added advantage of electrical control of the spin-related photocurrent in spintronic applications.

Bioinformatic analysis based on the complete coding region of the MSTN gene within and among different species

Myostatin, encoded by the MSTN gene (previously GDF8), is a member of the transforming growth factor-β superfamily, which normally acts to limit skeletal muscle mass by regulating the number and growth of muscle fibers. In this study, a total of 84 myostatin gene sequences with known complete coding regions (CDS) and corresponding amino acid sequences were analyzed from 17 species, and differentiation within and among species was studied using comparative genomics and bioinformatics. Characteristics of the nucleotide and amino acid sequences were also predicted. The results indicated that a total of 569 polymorphic sites, including 53 singleton variable sites and 516 parsimony informative sites, which could be sorted into 44 haplotypes, were detected from 17 species. Observed genetic diversity was higher among species than within species, and Vulpes lagopus was more polymorphic than other species. There was clear differentiation of the myostatin gene among species and the reconstructed phylogenetic tree was consistent with the NCBI taxonomy. The myostatin gene was 375-aa long in most species, except for Mus musculus (376 aa) and Danio rerio (373 aa). The amino acid sequences of myostatin were deemed hydrophilic, and had theoretical pI values of <7.0, mostly due to the acidic polypeptide. The instability index of the myostatin protein was 40.48-51.63, indicating that the polypeptide is not stable. The G+C content of the CDS nucleotide sequence in different species was 40.60-51.69%. The predicted promoter region of the Ovis aries myostatin gene was 150-220 bp upstream of the start codon.

Nanostructured conducting polymers and their biomedical applications

Much attention has been paid to nanostructured conducting polymers due to their unique properties, which arise from their nanoscale size, such as their large surface area, high electrical conductivity, electrochemical stability and quantum effects. This article reviews three methods to synthesize nanostructured conducting polymers and their applications in the biomedical field, focusing specifically on neural probes, biosensors, artificial muscles or actuators and controlled drug release. Challenges and future directions of these nanostructured conducting polymer are also discussed.

Fine mapping of f5-Du, a gene conferring wide-compatibility for pollen fertility in inter-subspecific hybrids of rice (Oryza sativa L.)

Wide-compatibility varieties (WCVs), comprising a special class of rice germplasm, are able to produce fertile hybrids when crossed with both indica and japonica varieties. Dular, a landrace variety from India, has both a wide spectrum and high level of wide-compatibility when crossed with a range of indica and japonica varieties. In previous studies, an allele at the f5 locus from Dular (f5-Du) was identified as a neutral allele conferring wide-compatibility with a large effect on both pollen and spikelet fertility. Using a population of 1993 hybrid plants derived from a cross between ZS(f5-Du/f5-ZS) (F1 of near isogenic line of Zhenshan 97 containing f5-Du) and Balilla (a japonica tester), f5-Du was genetically mapped to an interval of about 1.6 cM, with 0.8 cM from both SSR markers WFPM3 and WFPR1. Combined with bioinformatic analysis, a contig map was constructed for the f5 region, consisting of five bacterial artificial chromosome (BAC) or P1 artificial chromosome (PAC) clones and spanning approximately 437 kb in length. By assaying the recombinant events in the region with markers developed using the sequence information, the f5 locus was further narrowed down to a 70 kb fragment containing nine predicted genes. The result will be very useful for cloning this gene and marker-assisted transferring of the neutral allele in rice breeding programs.

Identification and confirmation of three neutral alleles conferring wide compatibility in inter-subspecific hybrids of rice (Oryza sativa L.) using near-isogenic lines

Wide-compatibility varieties (WCVs) are a special class of rice germplasm that is able to produce fertile hybrids when crossed to both indica and japonica subspecies. Previous studies determined 'Dular' and 02428 as two WCVs and identified a number of QTLs as having large effects on fertility of inter-subspecific hybrids. In this study, we developed five near-isogenic lines (NILs) for three of the QTLs, f5, f6 and S5, by backcrossing and marker-assisted selection, using "Dular" and 02428 as the donors and "Zhenshan 97" as the recipient. Three of the NILs each carried one introgressed allele, and two NILs each carried two introgressed alleles in combinations. The NILs were testcrossed to an indica tester "Nanjing 11" and a japonica tester "Balilla". The results showed that the f5 allele from "Dular"(f5-Du) is a neutral allele conferring wide compatibility, with a large effect on both pollen and spikelet fertility, and the f6 allele from "Dular" (f6-Du) is a neutral allele for spikelet fertility with smaller effect. The S5 allele from 02428 (S5-08) was confirmed to be a neutral allele for spikelet fertility. It is likely that f6 and S5 are the same locus as deduced by their genomic locations and effects. The results also showed that even in combination, two neutral alleles of different loci were not able to produce normal fertility hybrids in typical indica-japonica crosses. The implications of the findings in rice breeding programs are discussed.

Derivatization of fullerene dimer C120 by the Bingel reaction and a 3He NMR study of 3He@C120 monoadducts

Cyclopropanation with diethyl bromomalonate and base (the Bingel reaction) was conducted on fullerene dimer C120 to give a mixture of "monoadducts" (45% yield) and "bisadducts" (< or =37% yield), while 18% of the C120 remained unchanged. The "monoadducts" were separated into five positional isomers, i.e., e(face), e(edge), trans-4, trans-3, and trans-2, by preparative HPLC. Assignments were made based on 1H (and 13C) NMR and confirmed by theoretical calculations of the addends' 1H NMR chemical shifts. The relative yields of these isomers were in fair agreement with those observed for the Bingel bisaddition of C60. The Bingel reaction was also carried out on the dimer C120 encapsulating 3He in one of the C60 cages. Each positional isomer of the "monoadduct" exhibited a pair of 3He NMR signals corresponding to an isomer with functionalization on the 3He-containing cage and the other isomer with functionalization on the empty cage. Using the 3He NMR spectroscopy, a pair of signals for the trans-1 isomer, which eluded detection by 1H NMR, were observed, in addition to pairs of signals for e(face), e(edge), trans-4, trans-3, and trans-2 isomers. The 3He NMR signals for isomers with functionalization on the 3He-containing cage were spread out over a 1.82-ppm range reflecting the direct effects of the addition pattern on the C60 surface. In contrast, the isomers with functionalization on the empty cage exhibited 3He NMR signals that appeared over a 0.14-ppm range, which was shown to be primarily due to changes in the diamagnetism of the functionalized cage based on theoretical calculations of 3He NMR chemical shifts for the model system in which the C60 cage encapsulating 3He was removed.

Zinc inhibition of caspase-3 activation does not protect HeLa cells from apoptotic cell death

Zinc is proposed to be antiapoptotic for it has been shown to inhibit late events of apoptotic pathways such as Ca(2+)/Mg(2+)-dependent endonuclease cleavage of chromatin DNA, poly-ADP ribose polymerase cleavage, and caspase-3 activity. Because caspase-3 is a critical executioner caspase in apoptosis, this study was undertaken to examine specifically a correlation between zinc inhibition of caspase-3 activation and apoptosis in HeLa cells. Cultured HeLa cells were exposed to 100 microM ZnCl(2) for 1 h prior to 12 h treatment with 1.0 microM doxorubicin (DOX), an important anticancer agent that causes apoptosis in a wide variety of tumor cells. Western blot analysis of HeLa cells treated with DOX for 12 h revealed that DOX caused proteolytic activation of caspase-3 and zinc inhibited this activation. Interestingly, zinc did not inhibit DOX-induced apoptosis as measured by a terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay. Furthermore, a microculture tetrazolium assay confirmed that cell death occurred in the presence of zinc. These results demonstrate that zinc specifically inhibits DOX-induced activation of caspase-3 in HeLa cells, but does not suppress DOX-induced apoptosis or otherwise cell death, thus suggesting DOX-induced caspase-3 activation may not play a major role in overall cell death and/or non-caspase-3 pathways are involved in DOX-induced apoptosis in HeLa cells.

Metallothionein inhibits doxorubicin-induced mitochondrial cytochrome c release and caspase-3 activation in cardiomyocytes

Previous studies using transgenic mice in which metallothionein (MT) was overexpressed only in the heart have demonstrated that MT protects from oxidative cardiac injury induced by doxorubicin (DOX), an important anticancer agent. MT cardioprotection is associated with its antiapoptotic effect. The present study was undertaken to test the hypothesis that MT suppresses DOX-induced apoptosis through inhibition of mitochondrial cytochrome c release and caspase-3 activation. Primary cultures of cardiomyocytes isolated from the hearts of transgenic neonatal mice and nontransgenic controls were treated with DOX at a clinically relevant concentration (1.0 microM) for varying time periods. Apoptosis was detected in nontransgenic cardiomyocyte cultures by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling and Annexin V-fluorescein isothiocyanate binding. This apoptotic effect was significantly suppressed in the MT-overexpressing transgenic cardiomyocytes. Western blot analysis revealed that DOX caused mitochondrial cytochrome c release. Furthermore, caspase-3 activation was observed. The activation of this apoptotic pathway by DOX was dramatically inhibited in the MT-overexpressing cardiomyocytes. To elucidate the role of reactive oxygen species (ROS) in the activation of the cytochrome c-mediated caspase-3 activation pathway, the intracellular levels of ROS and their localization were detected by fluorescent confocal microscopy. Mitochondrial ROS concentrations were dramatically elevated by DOX in nontransgenic cardiomyocytes. This elevation was completely inhibited almost in the MT-overexpressing cardiomyocytes. Thus, these results demonstrate that MT suppresses DOX-induced apoptosis in cardiomyocytes through, at least in part, inhibition of the cytochrome c-mediated apoptotic pathway.

Inhibition of hypoxia/reoxygenation-induced apoptosis in metallothionein-overexpressing cardiomyocytes

To study possible mechanisms for metallothionein (MT) inhibition of ischemia-reperfusion-induced myocardial injury, cardiomyocytes isolated from MT-overexpressing transgenic neonatal mouse hearts and nontransgenic controls were subjected to 4 h of hypoxia (5% CO2-95% N2, glucose-free modified Tyrode's solution) followed by 1 h of reoxygenation in MEM + 20% fetal bovine serum (FBS) (5% CO2-95% air), and cytochrome c-mediated caspase-3 activation apoptotic pathway was determined. Hypoxia/reoxygenation-induced apoptosis was significantly suppressed in MT-overexpressing cardiomyocytes, as measured by both terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick-end labeling and annexin V-FITC binding. In association with apoptosis, mitochondrial cytochrome c release, as determined by Western blot, was observed to occur in nontransgenic cardiomyocytes. Correspondingly, caspase-3 was activated as determined by laser confocal microscopic examination with the use of FITC-conjugated antibody against active caspase-3 and by enzymatic assay. The activation of this apoptotic pathway was significantly inhibited in MT-overexpressing cells, as evidenced by both suppression of cytochrome c release and inhibition of caspase-3 activation. The results demonstrate that MT suppresses hypoxia/reoxygenation-induced cardiomyocyte apoptosis through, at least in part, inhibition of cytochrome c-mediated caspase-3 activation.

Reversible Diels-Alder addition to fullerenes: a study of equilibria using (3)He NMR spectroscopy

3He NMR spectroscopy has been used to study the equilibria of Diels-Alder additions of 9,10-dimethyl anthracene (DMA) to (3)He@C(60) and (3)He@C(70). Spectra of a series of equilibrium mixtures showed peaks for the isomeric adducts. One monoadduct, six bis-adducts, eleven tris-adducts, and ten tetrakis-adducts of DMA to C(60) were seen. One monoadduct and three bis-adducts of C(70) were detected. Equilibrium constants were found for these reactions and values for DeltaG, DeltaH, and DeltaS were obtained.

Suppression by metallothionein of doxorubicin-induced cardiomyocyte apoptosis through inhibition of p38 mitogen-activated protein kinases

Cardiomyopathy induced by doxorubicin (DOX) has long been a major impediment of clinical applications of this effective anticancer agent. Previous studies have shown that cardiac-specific metallothionein (MT)-overexpressing transgenic mice are highly resistant to DOX-induced cardiotoxicity. To investigate cellular and molecular mechanisms by which MT participates in this cytoprotection, transgenic mice containing high levels of cardiac MT and non-transgenic controls were treated intraperitoneally with DOX at a single dose of 15 mg/kg and sacrificed on the 4th day after treatment. Myocardial apoptosis was detected by a terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling assay and confirmed by electron microscopy of immunogold staining of apoptotic nuclei. Dual staining of cardiac alpha-sarcomeric actin using an immunohistochemical method further identified apoptotic myocytes. Apoptosis was significantly inhibited in the transgenic myocardium. The anti-apoptotic effect of MT was further revealed in primary cultures of neonatal mouse cardiomyocytes. Furthermore, DOX activated p38 mitogen-activated protein kinase (MAPK), which was critically involved in the apoptotic process, as demonstrated by inhibition of DOX-induced apoptosis by a p38-specific inhibitor, SB203580. Both DOX-induced p38 MAPK activation and apoptosis were dramatically inhibited in the transgenic cardiomyocytes. The results thus demonstrate that DOX induces apoptosis in cardiomyocytes both in vivo and in vitro and MT suppresses this effect through at least in part inhibition of p38 MAPK activation.

Metallothionein inhibits myocardial apoptosis in copper-deficient mice: role of atrial natriuretic peptide

Dietary copper restriction causes heart hypertrophy in animal models. Several studies have indicated that this cardiomyopathy is mediated by oxidative stress. Metallothionein (MT), a low molecular weight and cysteine-rich protein, functions in protecting the heart from oxidative injury. We therefore used a cardiac-specific MT-overexpressing transgenic mouse model to test the hypothesis that MT inhibits copper deficiency-induced heart hypertrophy. Dams of both transgenic pups and non-transgenic littermates were fed a copper-adequate or copper-deficient diet, starting on the fourth day post-delivery, and the weanling mice were continued on the dams' diets until they were killed. Heart hypertrophy developed in copper-deficient pups by the fourth week of the combined pre- and post-weaning feeding and aggressively progressed until the end of the experiment (6 weeks). MT overexpression did not prevent the occurrence of heart hypertrophy, but inhibited the progression of this cardiomyopathy, which correlated with its suppression of cardiac lipid peroxidation. Corresponding to the progression of heart hypertrophy, myocardial apoptosis and atrial natriuretic peptide (ANP) production in the left ventricle were detected in non-transgenic copper-deficient mice; these effects were significantly suppressed in transgenic copper-deficient mice. Measurement of apoptosis by TUNEL assay and Annexin V-FITC confocal microscopy in primary cultures of cardiomyocytes revealed that ANP was largely responsible for the myocyte apoptosis and that MT inhibited ANP-induced apoptosis. The data clearly demonstrate that elevation of MT in the heart inhibits oxidative injury and suppresses the progression of heart hypertrophy in copper deficiency, although it does not block its initiation. The results suggest that MT inhibits the transition from heart hypertrophy to failure by suppressing apoptosis through inhibition of both cardiac ANP production and its apoptotic effect.

Inhibition of doxorubicin toxicity in cultured neonatal mouse cardiomyocytes with elevated metallothionein levels

Controversial results have been reported regarding whether metallothionein (MT) functions in doxorubicin (DOX) detoxification in the heart. To determine unequivocally the role of MT in cardiac protection against the toxicity of DOX, ventricular cardiomyocytes isolated from 1- to 3-day neonatal transgenic mice with high levels of cardiac MT and from nontransgenic control animals were applied. On the 6th day of culturing, MT concentrations in the transgenic cardiomyocytes were about 2-fold higher than those in the nontransgenic cells. DOX was added directly into the cultures. Compared with nontransgenic controls, transgenic cardiomyocytes displayed a significant (p <.05) resistance to DOX cytotoxicity, as measured by morphological alterations, cell viability, and lactate dehydrogenase leakage from the cells. This cytoprotective effect of MT correlated with its inhibition of DOX-induced lipid peroxidation. These observations demonstrate unequivocally that elevation of MT concentrations in the cardiomyocytes of 2-fold higher than normal provides efficient protection against DOX toxicity.

Metallothionein-overexpressing neonatal mouse cardiomyocytes are resistant to H2O2 toxicity

To study cellular and molecular events of cardiac protection by metallothionein (MT) from oxidative injury, a primary neonatal cardiomyocyte culture was established from a specific cardiac MT-overexpressing transgenic mouse model. Ventricular cardiomyocytes were isolated from 1- to 3-day-old neonatal mice and cultured in an Eagle's minimum essential medium supplemented with 20% fetal bovine serum under an atmosphere of 5% CO2-95% air at 37 degreesC. Forty-eight hours after plating was completed, the purity of such cultures was 95% myocytes, assessed by an immunocytochemical assay. Over 80% of the cardiomyocytes beat spontaneously on the first day of culture and synchronously in a confluent monolayer after the sixth day of culture. Cellular MT concentrations in the transgenic cardiomyocytes before culturing and on the sixth day postculturing were about seven- and twofold higher than nontransgenic controls, respectively. However, there were no significant differences in cell morphology, glutathione content, and antioxidant enzymatic activities between these two types of cardiomyocytes. When these cells were challenged by H2O2, the transgenic cardiomyocytes displayed a significant resistance to the toxic effect of this oxidant, as measured by cell viability, lactate dehydrogenase leakage, and morphological alterations. In addition, the transgenic cells were highly protected from H2O2-induced lipid peroxidation. These observations demonstrate that MT protects the cultured cardiomyocytes from H2O2 toxicity by preventing its interaction with macromolecules such as lipids, and this cultured primary neonatal mouse cardiomyocyte system provides a valuable tool to directly study cellular and molecular events of MT in cardiac protection against oxidative injury.

Radionuclide bone imaging as a means of differentiating loosening and infection in patients with a painful total hip prosthesis

Twenty patients with 23 painful total hip prostheses were examined by radionuclide imaging (20 cases), arthrography (11 cases), needle aspiration (9 cases), and surgery (19 cases) for the purpose of assessing loosening and/or infection. Bone imaging was most accurate, showing three main distributions of activity: (a) ectopic calcification, (b) focal increased activity at the upper and lower ends of the femoral prosthesis, and (c) diffuse activity. These findings suggest that infection and loosening can be differentiated in many instances. None of the patients with focal activity had infection, compared to 2 of the 3 patients with diffuse uptake.