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.

Rapid point-of-care test for diagnosis of peritonitis in peritoneal dialysis patients

BACKGROUND

Periplex® is a rapid point-of-care test based on the detection of interleukin-6 (IL-6) or matrix metalloproteinase-8 (MMP-8) to diagnose peritonitis in peritoneal dialysis (PD) patients.

METHODS

This single-centre study was conducted in Singapore General Hospital from 2019 to 2022. The study recruited PD patients suspected of having peritonitis. Periplex was performed at the presentation and recovery of peritonitis. Primary outcomes were sensitivity and specificity of Periplex at presentation. The positive and negative predictive values of tests were also performed.

RESULTS

A total of 120 patients were included in the study. The mean age was 60.9 ± 14.9 years, 53% were male, 79% were Chinese and 47.5% had diabetes mellitus. Periplex was positive in all patients with peritonitis (n = 114); sensitivity of 100%; 95% confidence interval (CI): 100-100%. Periplex was falsely positive in three patients with non-infective eosinophilic peritonitis, resulting in a low specificity of 50%; 95% CI: 41.1-59.0%. Periplex had a positive predictive value of 97.4% and a negative predictive value of 100%. During recovery from peritonitis, Periplex had high specificity (93.6%) and negative predictive value (98.7%) to indicate the resolution of infection. MMP-8 was more sensitive than IL-6 in detecting peritonitis. Periplex was positive in all patients with peritonitis regardless of the types of PD solutions used.

CONCLUSIONS

Periplex had high sensitivity, and positive and negative predictive values in the diagnosis of peritonitis can be considered as a screening tool for peritonitis. Given its high specificity and negative predictive value, it may also be used to document the resolution of peritonitis.

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.

[Analysis of the clinical characteristics and misdiagnosis of area postrema syndrome manifesting as intractable nausea, vomiting, and hiccups in neuromyelitis optica spectrum disorders]

Objective: To investigate the misdiagnosis of area postrema syndrome (APS) manifesting as intractable nausea, vomiting and hiccups in neuromyelitis optic spectrum disease (NMOSD) and reduce the risk of misdiagnosis. Methods: We retrospectively analyzed data from NMOSD patients attending the Department of Neurology at the First Medical Center of PLA General Hospital between January 2019 and July 2021. SPSS25.0 was then used to analyze the manifestations, misdiagnosis, and mistreatment of APS. Results: A total of 207 patients with NMOSD were included, including 21 males and 186 females. The mean age of onset was 39±15 years (range: 5-72 years). The proportion of patients who were positive for serum aquaporin 4 antibody was 82.6% (171/207). In total, 35.7% (74/207) of the NMOSD patients experienced APS during the disease course; of these patients, 70.3% (52/74) had APS as the first symptom and 29.7% (22/74) had APS as a secondary symptom. The misdiagnosis rates for these conditions were 90.4% (47/52) and 50.0% (11/22), respectively. As the first symptom, 19.2% (10/52) of patients during APS presented only with intractable nausea, vomiting and hiccups; 80.8% (42/52) of patients experienced other neurological symptoms. The Departments of Gastroenterology and General Medicine were the departments that most frequently made the first diagnosis of APS, accounting for 54.1% and 17.6% of patients, respectively. The most common misdiagnoses related to diseases of the digestive system and the median duration of misdiagnosis was 37 days. Conclusions: APS is a common symptom of NMOSD and is associated with a high rate of misdiagnosis. Other concomitant symptoms often occur with APS. Gaining an increased awareness of this disease/syndrome, obtaining a detailed patient history, and performing physical examinations are essential if we are to reduce and avoid misdiagnosis.

Constraints on Heavy Decaying Dark Matter from 570 Days of LHAASO Observations

The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γ rays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 10^{5} and 10^{9}  GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission.

[Research progress of airway microbiome and airway immune response in asthma]

Bronchial asthma (asthma) is one of the most common chronic airway diseases, with more than 300 million people worldwide suffering from this disease. In recent years, studies have shown that compared with healthy people, the airway microecological structure and relative abundance of various flora of asthmatic patients have changed, and are related to the airway inflammatory phenotype of asthma. Airway microecology can affect the occurrence and development of asthma through immune response. The mechanism of interaction between airway microecology and asthma can provide new ideas for the accurate treatment of asthma. This article mainly reviewed the current research on airway microecology in asthma, and puts forward prospects for the accurate treatment of asthma in the future.

Exploring Lorentz Invariance Violation from Ultrahigh-Energy γ Rays Observed by LHAASO

Recently, the LHAASO Collaboration published the detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with the highest energy photon reaching 1.4 PeV. The first detection of PeV γ rays from astrophysical sources may provide a very sensitive probe of the effect of the Lorentz invariance violation (LIV), which results in decay of high-energy γ rays in the superluminal scenario and hence a sharp cutoff of the energy spectrum. Two highest energy sources are studied in this work. No signature of the existence of the LIV is found in their energy spectra, and the lower limits on the LIV energy scale are derived. Our results show that the first-order LIV energy scale should be higher than about 10^{5} times the Planck scale M_{Pl} and that the second-order LIV scale is >10^{-3}M_{Pl}. Both limits improve by at least one order of magnitude the previous results.

Peta-electron volt gamma-ray emission from the Crab Nebula

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10^-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 10³⁶ ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622+3749 Observed by LHAASO-KM2A

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25  TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160  TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 10¹⁵ electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays¹. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. ²). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane^3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

[Clinicopathological significance of Golgi phosphoprotein 3 expression in papillary thyroid carcinoma]

Objective: To investigate the expression of Golgi phosphoprotein 3 (GOLPH3) in papillary thyroid carcinoma (PTC) and its relationship with clinicopathological characteristics of PTC and American Thyroid Association (ATA) risk of recurrence stratification. Methods: The mRNA expression level of GOLPH3 in PTC tissues and the matched adjacent noncancerous tissues from 30 cases of PTC undergoing surgical operation in Fujian Provincial Hospital between March 2017 and April 2018 was detected by reverse transcription-quantitative PCR (RT-qPCR). The protein expression of GOLPH3 in PTC tissues and the matched adjacent noncancerous tissues of 135 cases of PTC between January 2013 and April 2018 was measured by immunohistochemistry. The correlation between the expression of GOLPH3 in PTC and clinicopathologic characteristics and ATA risk of recurrence stratification was analyzed. Results: The mRNA level of GOLPH3 in PTC tissues was significantly higher than that in adjacent noncancerous tissues (7.53±1.32 vs 3.64±1.44, P<0.001). The protein expression level of GOLPH3 in PTC tissues was significantly higher than that in adjacent noncancerous tissues [66(30, 95) vs 34(20, 72), P<0.001]. The expression of GOLPH3 was significantly correlated to the tumor size (P=0.026), extrathyroid invasion (P=0.016), lymph node metastasis (P=0.001) and TNM stage (P=0.027) in PTC. Multivariate logistic regression analysis showed that GOLPH3 expression was independently correlated to tumor size (OR=3.58, 95%CI: 1.19-15.46, P=0.017) and lymph node metastasis (OR=7.28, 95%CI: 2.43-10.08, P=0.002). The expression of GOLPH3 was positively correlated to ATA risk of recurrence stratification (P=0.041). Conclusions: Overexpression of GOLPH3 is associated with the development of PTC and poor prognosis in patients with PTC. Detection of GOLPH3 expression can help evaluate proliferative and metastatic potential of PTC, as well as the risk of postoperative recurrence in patients with PTC.

[Two cases report of laryngeal malignant melanoma and a review of literatures]

Summary Two patients both complained of one year history of hoarseness and the clinical manifestations and imageology among 2 patients were lack of specificity. The pathological tissue was successfully eradicated by surgical removal. Histopathology established laryngeal malignant melanoma as the diagnosis. The clinical manifestations and imageology were lack specificity between laryngeal malignant melanoma, laryngeal cancer and other malignant tumor, the diagnosis is difficult, often confirmed by postoperative pathology, the treatment is often by surgery and have a poor prognosis.

Enhanced metabolic function of human hepatocytes cryopreserved with low concentration me2so and polyol additives at -80C

The metabolic function of cryopreserved cells, in addition to cell viability after thawing, is an important parameter in any successful cryopreservation protocol. Dimethyl sulfoxide (Me2SO) is known to affect the differentiation of recovered cells. In this study, we report that sugars and sugar alcohols increases cell recovery, and also improves the metabolic function of human hepatocytes that are cryopreserved using low concentration Me2SO (5%). Three sugars (glucose, sucrose, and trehalose) and three sugar alcohols (xylitol, maltol, and sorbitol) have been tested. Cell viability after thaw and 24-h post-thaw attachment rate of cryopreserved human hepatocytes were assessed. Post-thaw metabolic activities (albumin, glucose, urea content) were measured, and cell proliferation was observed with inverted microscope. Cell viability, post-thaw attachment rate and metabolic activity of cryopreserved hepatocytes are enhanced by the addition of 0.4M sorbitol into 5% Me2SO solution. The study concludes that 5% Me2SO + 0.4M sorbitol can replace the 10% Me2SO method for cryopreservation of human hepatocytes at -80C freezer. The new solution may reduce the side effects on the patients and improve the safety of using cryopreserved hepatocytes.

Solution conformation of gramicidin S: An intramolecular nuclear Overhauser effect study

The solution conformation of gramicidin S in deuterated dimethyl sulfoxide was investigated by using the intramolecular nuclear Overhauser effect experiment. Experimental Overhauser enhancements were compared with predicted values for each of the nine most-stable conformations (M1-M9) calculated by Dygert et al. on the basis of energy-minimization procedures [Dygert, M., Gō, N. & Scheraga, H. A. (1975) Macromolecules 8, 750-761]. By using statistical hypothesis testing, the three lowest-energy conformations (M1, M2, and M3) were shown to give the best fit with the experimental data. All other conformations (M4-M9) were found to be inconsistent with the experimental data.

Glycosylasparaginase inhibition studies: competitive inhibitors, transition state mimics, noncompetitive inhibitors

Glycosylasparaginase catalyzes the hydrolysis of the N-glycosylic bond between asparagine and N-acetylglucosamine in the catabolism of N-linked glycoproteins. Previously only three competitive inhibitors, one noncompetitive inhibitor, and one irreversible inhibitor of glycosylasparaginase activity had been reported. Using human glycosylasparaginase from human amniotic fluid, L-aspartic acid and four of its analogues, where the alpha-amino group was substituted with a chloro, bromo, methyl or hydrogen, were competitive inhibitors having Ki values between 0.6-7.7 mM. These results provide supporting evidence for a proposed intramolecular autoproteolytic activation reaction. A proposed phosphono transition state mimic and a sulfo transition state mimic were competitive inhibitors with Ki values 0.9 mM and 1.4 mM, respectively. These results support a mechanism for the enzyme-catalyzed reaction involving formation of a tetrahedral high-energy intermediate. Three analogues of the natural substrate were noncompetitive inhibitors with Ki values between 0.56-0.75 mM, indicating the presence of a second binding site that may recognize (substituted)acetamido groups.

Essential role of Drosophila Hdac1 in homeotic gene silencing

Deacetylation of the N-terminal tails of core histones plays a crucial role in gene silencing. Rpd3 and Hda1 represent two major types of genes encoding trichostatin A-sensitive histone deacetylases. Although they have been widely found, their cellular and developmental roles remain to be elucidated in metazoa. We show that Drosophila Hdac1, an Rpd3-type gene, interacts cooperatively with Polycomb group repressors in silencing the homeotic genes that are essential for axial patterning of body segments. The biochemical copurification and cytological colocalization of HDAC1 and Polycomb group repressors strongly suggest that HDAC1 is a component of the silencing complex for chromatin modification on specific regulatory regions of homeotic genes.

Glycosylasparaginase activity requires the alpha-carboxyl group, but not the alpha-amino group, on N(4)-(2-Acetamido-2-deoxy-beta-D-glucopyranosyl)-L-asparagine

Glycosylasparaginase catalyzes the hydrolysis of the N-glycosylic bond in N(4)-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-L-asparagine in the catabolism of N-linked oligosaccharides. A deficiency, or absence, of enzyme activity gives rise to aspartylglycosaminuria, the most common disorder of glycoprotein metabolism. The enzyme catalyzes the hydrolysis of a variety of asparagine and aspartyl compounds containing a free alpha-carboxyl group and a free alpha-amino group; computational studies suggest that the alpha-amino group actively participates in the catalytic mechanism. In order to study the importance of the alpha-carboxyl group and the alpha-amino group on the natural substrate to the reaction catalyzed by the enzyme, 14 analogues of the natural substrate were studied where the structure of the aspartyl group of the substrate was changed. The incremental binding energy (DeltaDeltaGb) for those analogues that were substrates was calculated. The results show that the alpha-amino group may be substituted with a group of comparable size, for the alpha-amino group contributes little, if any, to the transition state binding energy of the natural substrate. The alpha-amino group position acts as an "anchor" in the binding site for the substrate. On the other hand, the alpha-carboxyl group is necessary for enzyme activity; removal of the alpha-carboxyl group or changing it to an alpha-carboxamide group results in no hydrolysis reaction. Also, N-acetyl-D-glucosamine is not sufficient for binding to the active site for efficient hydrolysis by the enzyme. These results provide supporting evidence for a proposed intramolecular autoproteolytic activation reaction for the enzyme. However, the results raise a question as to an important role for the alpha-amino group in the catalytic mechanism as indicated in computational studies.

Nonthermal production of weakly interacting massive particles and the subgalactic structure of the universe

There is increasing evidence that conventional cold dark matter (CDM) models lead to conflicts between observations and numerical simulations of dark matter halos on subgalactic scales, which rules out the favored candidates for CDM, namely weakly interacting massive particles (WIMPs). We propose a mechanism of nonthermal production of WIMPs and study its implications on the power spectrum. Our results show that, in this context, WIMPs as candidates for dark matter can work well both on large scales and on subgalactic scales.

"Paper-clip" type triple helix formation by 5'-d-(TC)3Ta(CT)3Cb(AG)3 (a and b = 0-4) as a function of loop size with and without the pseudoisocytosine base in the Hoogsteen strand

The formation of a DNA "paper-clip" type triple helix (triplex) with a common sequence 5'-d-(TC)(3)T(a)()(CT)(3)C(b)()(AG)(3) (a and b = 0-4) was studied by UV thermal melting experiments and CD spectra. These DNA oligomers form triplexes and duplexes under slightly acidic and neutral conditions, respectively. The stability of the formed triplexes (at pH 4.5) or duplexes (at pH 7.0 or 8.0) does not vary significantly with the size of the loops (a and b = 1-4). At pH 6.0, the triplex stability is, however, a function of a and b. It is also interesting to note that the oligomer 5'-d-(TC)(3)(CT)(3)(AG)(3) (a and b = 0) forms a stable triplex at pH 4.5 with a slightly lower T(m) value, due to dissociation of a base triad at one end and a distorted base triad at the other, observed by (1)H NMR. Thus, we have here a model system, 5'-d-(TC)(3)T(a)(CT)(3)C(b)(AG)(3), that could form a triplex effectively with (a and b = 1-4) and without (a and b = 0) loops under acidic conditions. In addition, the triplex formation of oligomers with replacement of one, two, or three 2'-deoxycytidine in the Hoogsteen strand by either 2'-deoxypseudoisocytidine (D) or 2'-O-methylpseudoisocytidine (M) was also studied in the sequence 5'-d-(TX)(3)T(2)(CT)(3)C(2)(AG)(3) (where X is C, D, or M). Both CD spectra and UV melting results showed that only D3 [(TX)(3) = (TD)(3)] and M3 [(TX)(3) = (TM)(3)] were able to form the paper-clip structure under both neutral and acidic conditions. This is because the N(3)H of a pseudoisocytosine base can serve as a proton donor without protonation. We hereby proved that the 2'-deoxypseudoisocytidine, similar to 2'-O-methylpseudoisocytidine, could replace 2'-deoxycytidine in the Hoogsteen strand to provide triplex formation at neutral pH.

Plasma transforming growth factor-beta1 level before radiotherapy correlates with long term outcome of patients with lung carcinoma

BACKGROUND

Plasma transforming growth factor-beta1 (TGFbeta1) levels are increased in many malignancies at the time of diagnosis, including all forms of lung carcinoma. Therefore, the potential use of TGFbeta1 as a plasma marker to predict the long term outcome of lung carcinoma patients treated with radiotherapy (RT) was evaluated.

METHODS

Plasma samples for 59 newly diagnosed lung carcinoma patients were assayed for TGFbeta1 before RT (pre RT), at the end of RT (end RT), and during follow-up after RT. TGFbeta1 was extracted from plasma using an acid-ethanol method. An enzyme-linked immunoadsorbent assay was used to quantify the plasma TGFbeta1 levels. The normal value for this assay is < or =7.5 ng/mL. Disease status at last follow-up was without knowledge of TGFbeta1 levels. Comparisons within groups and between groups were estimated using analysis of variance and the Student t test for unpaired data, respectively.

RESULTS

The 59 patients were divided into 2 groups according to their disease status at last follow-up: those with no evidence of disease (NED) (n = 13) and those with disease (WD) (n = 46). The median follow up was 26.8 months and 12.4 months, respectively, for the NED and WD groups. No significant differences were found in the clinical characteristics between the two groups. The plasma TGFbeta1 level before RT was significantly higher in the WD group (mean +/- standard error of the mean [SEM] = 12.5+/-1.7 ng/mL; median = 8.6 ng/mL) compared with the NED group (mean +/- SEM = 6.0+/-1.0 ng/mL; median = 6.0 ng/mL) (P = 0.037). At the time of last follow-up, WD patients had a significantly higher plasma TGFbeta1 level (mean +/- SEM = 11.6+/-1.3 ng/mL; median = 9.6 ng/mL) compared with NED patients (mean +/- SEM = 3.7+/-0.5 ng/mL; median = 3.6 ng/mL) (P = 0.002).

CONCLUSIONS

These data demonstrate that plasma TGFbeta1 may be a useful tumor marker in patients with lung carcinoma.

[Repair of huge skin defect on leg and foot with multiple pedicled blocking randomized fasciocutaneous flap]

OBJECTIVE

In order to increase the survival area of pedicled fasciocutaneous flap, a multiple pedicled blocking randomized fasciocutaneous flap was designed.

METHODS

From January 1991 to September 1998, this technique was used to repair 33 cases, including 27 males and 6 females and the ages ranged from 6 to 58 years. All of the patients were suffered from traffic accidents. In these cases, 22 cases had skin defects of legs and feet with bone, nerve and tendon exposed, 5 cases had osteomyelitis as well as internal fixaters exposed and the other 6 had deformity from scar. The size of the flap was 25.0 cm x 13.0 cm x 2.4 cm at its maximum and 6.0 cm x 3.5 cm x 1.5 cm at its minimum. Based on the traditional blocking flap, according to the severity of the wound and conditions of the neighboring tissues, a flap having 2 to 4 orthogonal pedicles with a width of 1.5 to 3.0 cm was designed. The medical-graded stainless steel sheet was implanted below the deep fascia, and after blocking for 3 to 6 days, the side pedicles were divided. 6 to 14 days later, one of the two remaining pedicles was divided and was transferred to repair the defect.

RESULTS

31 cases were followed up for 6 months to 5 years without any trouble of the joints. The flap had a good external appearance and was high pressure-resistant.

CONCLUSION

The multiple pedicled blocking randomized fasciocutaneous flap increased the size of the flap and the length to width ratio. It had the following advantages: manage at will, high resistance to infection and a large survival area of flap.

Breaking the low barrier hydrogen bond in a serine protease

The serine protease subtilisin BPN' is a useful catalyst for peptide synthesis when dissolved in high concentrations of a water-miscible organic co-solvent such as N,N-dimethylformamide (DMF). However, in 50% DMF, the k(cat) for amide hydrolysis is two orders of magnitude lower than in aqueous solution. Surprisingly, the k(cat) for ester hydrolysis is unchanged in 50% DMF. To explain this alteration in activity, the structure of subtilisin 8397+1 was determined in 20, 35, and 50% (v/v) DMF to 1.8 A resolution. In 50% DMF, the imidazole ring of His64, the central residue of the catalytic triad, has rotated approximately 180 degrees around the Cbeta-Cgamma bond. Two new water molecules in the active site stabilize the rotated conformation. This rotation places His64 in an unfavorable geometry to interact with the other members of the catalytic triad, Ser221 and Asp32. NMR experiments confirm that the characteristic resonance due to the low barrier hydrogen bond between the His64 and Asp32 is absent in 50% DMF. These experiments provide a clear structural basis for the change in activity of serine proteases in organic co-solvents.

Functional reconstruction of trans regulation of the Ultrabithorax promoter by the products of two antagonistic genes, trithorax and Polycomb

Maintenance of the "on-off" state of Drosophila homeotic genes in Antennapedia and bithorax complexes requires activities of the trithorax and Polycomb groups of genes. To identify cis-acting sequences for functional reconstruction of regulation by both trithorax and Polycomb, we examined the expression patterns of several Ubx-lacZ transgenes that carry upstream fragments corresponding to a region of approximately 50 kb. A 14.5-kb fragment from the postbithorax/bithoraxoid region of Ultrabithorax exhibited proper regulation by both trithorax and Polycomb in the embryonic central nervous system. Using a Drosophila haploid cell line for transient expression, we found that trithorax or Polycomb can function independently through this upstream fragment to activate or repress the Ultrabithorax promoter, respectively. Studies of deletion mutants of trithorax and Polycomb demonstrated that trithorax-dependent activation requires the central zinc-binding domain, while Polycomb-dependent repression requires the intact chromodomain. In addition, trithorax-dependent activity can be abrogated by increasing the amount of Polycomb, suggesting a competitive interaction between the products of trithorax and Polycomb. Deletion analysis of this fragment demonstrated that a 440-bp fragment contains response elements for both trithorax and Polycomb. Furthermore, we showed that the integrity of the proximal promoter region is essential for trithorax-dependent activation, implicating a long-range interaction for promoter activation.

The crystal and molecular structure of trichosanthin at 2.6 A resolution

The crystallographic refinement of trichosanthin has been performed at 2.6 A resolution. The crystal and molecular structure of trichosanthin is described in detail in this paper. On summarizing the regularity of the amino acid sequences of eight kinds of ribosome inactivating proteins and combining with the crystal and molecular structure of trichosanthin, fifteen most conservative amino acid residues are analyzed. It is found that four most conservative polar amino acid residues Gln156, Glu160, Arg163 and Glu189 gather on the molecular surface on the boundary of the large and small domains, thus forming the active center of the protein molecule.

Proton NMR and optical spectroscopic studies on the DNA triplex formed by d-A-(G-A)7-G and d-C-(T-C)7-T

Triplex and duplex formation of two deoxyribohexadecamers d-A-(G-A)-G (a) and d-C-(T-C)-T (b) have been studied by UV, CD, fluorescence, and proton NMR spectroscopy. Optical studies of a and b at dilute concentrations (microM range) yielded results similar to those seen for polymers of the same sequence, indicating that these hexadecamers have properties similar to the polymers in regard to triplex formation. The CD spectra of concentrated NMR samples (mM range) are similar to those observed at optical concentrations at both low and high pH, making possible a correlation between CD and NMR studies. In NMR spectra, two imido NH-N hydrogen bonded resonance envelopes at 12.6 and 13.7 ppm indicate that only the duplex conformation is present at pH greater than 7.7. Four new NH-N hydrogen-bonded resonance envelopes at 12.7, 13.5, 14.2, and 14.9 ppm are observed under acidic conditions (pH 5.6) and the two original NH-N resonances gradually disappear as the pH is lowered. Assignment of these four peaks to Watson-Crick G.C. Hoogsteen T.A Watson-Crick A.T, and Hoogsteen C+.G hydrogen-bonded imidos, respectively, confirm the formation of triple-stranded DNA NMR results also show that triplex is more stable than duplex at the same salt condition and that triplex melts to single strands directly without going through a duplex intermediate. However, in the melting studies, a structural change within the triple-stranded complex is evident at temperatures significantly below the major helix-to-coil transition. These studies demonstrate the feasibility of using NMR spectroscopy and oligonucleotide model compounds a and b for the study of DNA triplex formation.

Structure of the type-specific polysaccharide antigen of Streptococcus rattus

The structure of the type-specific polysaccharide antigen of Streptococcus rattus was determined by methylation analysis, periodate oxidation, and by 2D-1H- and 13C-n.m.r.-spectroscopy. The polysaccharide was found to possess the trisaccharide repeating unit----3)-alpha-L-Rhap-(1----2)-[alpha-D-Galp-(1----3)]-alpha-L-+ ++Rhap- (1----.

A cyclophosphamide/DNA phosphoester adduct formed in vitro and in vivo

The antitumor activity of cyclophosphamide is thought to be due to the alkylating activity of phosphoramide mustard, a metabolite of cyclophosphamide. Reaction of 2'-deoxyguanosine 3'-monophosphate and phosphoramide mustard resulted in the formation of several adducts that could be detected by high performance liquid chromatography (HPLC). One of these adducts, isolated and purified by HPLC, could be detected by 32P postlabeling. This product was identified by UV, nuclear magnetic resonance, and mass spectrometry and by acid, base, and enzymatic hydrolysis to be 2'-deoxyguanosine 3'-monophosphate 2-(2-hydroxyethyl)aminoethyl ester. A combination of HPLC fractionation of digested DNA and 32P postlabeling was used to detect this adduct in calf thymus DNA incubated in vitro with metabolically activated cyclophosphamide and in DNA from the liver of mice treated with cyclophosphamide. In these DNA samples the adduct occurred at a level of 1/10(5) and 1/3 x 10(7) nucleotides, respectively.

The trithorax gene, a trans-acting regulator of the bithorax complex in Drosophila, encodes a protein with zinc-binding domains

The trithorax (trx) gene functions in segment determination in Drosophila through interaction with genes of the bithorax complex and Antennapedia complex. Genetic evidence suggests that trx may be considered a positive regulator of homeotic genes. Sequencing of cDNAs corresponding to the entire trx transcription unit revealed the existence of an unusually long open reading frame encoding 3759 amino acids. The main features of the predicted trx protein are several cysteine-rich regions which can be folded into zinc finger-like domains. Cysteine-rich portions expressed from trx cDNAs in Escherichia coli are capable of zinc binding in vitro, suggesting a possible function for the trx product as a metal-dependent DNA-binding protein. Analysis of trx mutant embryos with antibody to the Ultrabithorax (Ubx) gene product showed decreased staining in parasegment 6 of the ventral nerve cord of late embryos. However, expression of Ubx was not affected in embryos carrying the lethal mutation trxE3, in which one of the putative zinc finger-like domains of the trx protein is deleted. This differential effect of the E3 mutation suggests that trx exhibits other function(s) besides those involved in the regulation of Ubx expression in the ventral nerve cord of the embryo.

The maternal-effect gene fsh is essential for the specification of the central region of the Drosophila embryo

The maternal-effect gene, female sterile (1) homeotic (fsh), has been implicated in the determination of segmental organization and identity. We have analyzed the spatial patterns of expression of several segmentation and homeotic genes in fsh-deficient embryos. We observed perturbations in the expression of the Ultrabithorax gene in parasegments 6, 7, and 8, consistent with the domain in which homeotic transformations occur in adults derived from such embryos. Further, the expression of the gap gene Krüppel and the pair-rule gene even-skipped is altered, especially in the central region of the embryo. Our results suggest that the defects in segmental organization in fsh-deficient progeny are mediated primarily but not exclusively through a restriction of the domain of Krüppel expression.

Two-dimensional proton NMR studies on poly(VPGVG) and its cyclic conformational correlate, cyclo(VPGVG)3

Two-dimensional nuclear Overhauser enhancement (2D NOESY) data are reported for the polypentapeptide of elastin, poly(VPGVG), and the cyclopentadecapeptide, cyclo(VPGVG)3. In both, the repeating type II Pro2-Gly3 beta-turn can be derived from the NOE data, providing confirmation of many previous studies. In addition, other through-space connectivities are detailed that also compare favorably with previously determined crystal and solution structures for cyclo(VPGVG)3. Also, near identical data for the cyclopentadecapeptide and the polypentapeptide demonstrate the cyclic conformation-linear (helical) conformational correlate relationship between the two molecules. The 2D NOESY experiment is seen to be an effective means of establishing the presence or absence of a conformational relationship between a cyclic repeating sequence and its higher molecular weight linear counterpart. This is an approach of substantial practical value when developing the conformation of sequential polypeptides and when attempting to identify the presence of the conformation of a repeating peptide sequence within a more complex primary structure. Having established the basic conformational relationship between a cyclic conformation and its linear helical counterpart, cross peaks present in the linear helical structure that are not present in the cyclic conformational correlate can provide information on the interactions between adjacent turns of the helix. In this connection, a Val gamma CH3 in equilibrium Pro beta CH2 interaction is reported that can be the basis for determining the number of pentamers per turn of helix once it is determined whether it is dominantly the Val1 or Val4 gamma CH3 that is interacting with the Pro2 beta CH2.

Activation of the adenovirus EIIa late promoter by a single-point mutation which enhances binding of transcription factor IID

We have converted the TACAAA sequence present at position -29 of the adenovirus EIIa late promoter into a canonical TATA box by oligonucleotide-directed mutagenesis. When linear templates were analyzed in nuclear extracts, transcription of the mutant promoter showed a 10-fold higher level of activity than that of the wild-type promoter. This increase was correlated with an increased affinity of the mutant promoter for transcription initiation factor IID. Further analyses demonstrated that the activating functions of three EIIa late upstream promoter elements (Huang, D.-H., and Roeder, R.G. (1988) Mol. Cell. Biol. 8, 1906-1914) were maintained in the mutant promoter background. These observations indicated, first, that the upstream elements did not act merely to overcome a rate-limiting initiation step imposed by an inefficient TATA element and, second, that the strength of the interaction between transcription initiation factor IID and the TATA box was directly related to promoter activity.

1H NMR study of the solution structure of the self-complementary dodecanucleotide d(TGCA)3

The deoxyoligonucleotide d(TGCA)3 is a candidate for exhibiting unusual conformations. Its 1H NMR spectrum under low salt conditions has been obtained at 400 MHz and assigned using two-dimensional NMR techniques. The sugar puckers and glycosidic torsions have been determined by inspecting the relative intensities of the intranucleotide NOEs and COSY crosspeaks. At low electrolyte concentration (100 mM NaCl) the molecule exists as a right-handed duplex with twelve Watson-Crick base-pairs and deoxyribose moieties assuming the O1'-endo to C1'-exo pucker.

A simple approach to prenatal diagnosis of beta-thalassemia in a geographic area where multiple mutations occur

We describe a simple approach for detecting beta-thalassemia mutations in geographic areas such as southern China where multiple mutations are known to occur. Segments of the beta-globin gene were amplified in vitro by using the polymerase chain reaction. Dot blot hybridization of the amplified DNA with oligonucleotide probes corresponding to the six mutations found in southern China could directly identify the mutations causing beta-thalassemia in the affected families. The increased number of target sequences after amplification allows the use of 35S-labeled probes, which are reusable for up to 3 months. The mutations can be determined in two days.

Structure of the group G streptococcal polysaccharide

The structure of the group-specific polysaccharide of group G Streptococcus was determined by means of methylation analysis and selective chemical degradations. The anomeric configurations and conformations of the sugar residues were studied by 1H- and 13C-n.m.r. spectroscopy. The tetrasaccharide repeating unit, ----3)-alpha-D-Galp-(1----2)-[alpha-L-Rhap-(1----3)-beta-D-GalpNAc - (1----4)]-alpha-L-Rhap-(1----, was determined.

Proton nuclear magnetic resonance measurement of the amide hydrogen exchange rates of group A streptococcal polysaccharide in H2O

The solvent exchange rates of the acetamido hydrogen of the 2-acetamido-2-deoxy-beta-D-glucopyranosyl unit of group A streptococcal polysaccharide dissolved in H2O have been measured and compared with the corresponding exchange rates in the solvated model compound 1-O-methyl-2-acetamido-2-deoxy-beta-D-glucopyranoside. Amide hydrogen exchange rates were measured at 25 degrees C over a wide pH range by a combination of two separate NMR techniques: the transfer of solvent saturation and the amide hydrogen saturation recovery NMR experiments. The data indicate that the acetamido hydrogen essentially exists in a solvated environment and that its contribution to the conformational stability of this polysaccharide through intramolecular hydrogen bonding is negligible.

13C-N.M.R. study of the conformation of helical complexes of amylodextrin and of amylose in solution

Amylose (average d.p. 1000) and amylodextrin (average d.p. 25) have identical 13C-n.m.r. spectra, except for some minor signals from the small amount of alpha-1----6 branch linkages present in amylodextrin. Amylodextrin can be obtained as stable solutions in much higher concentrations than amylose and so requires only 1/100th as many scans to obtain a spectrum comparable to that of amylose. 13C-N.m.r. spectroscopy has been used to study the formation of amylodextrin complexes with organic complexing agents in aqueous solution. A control study using dextran, which does not form helical complexes, showed that, when complexing agents are added, the signals from all of the carbons show a slight downfield shift due to a general solvent effect. In the case of amylodextrin, the addition of increasing concentrations of complexing agent also produced a downfield shift of the signals of all the carbons, but there was a greater shift of the signals for carbons 1 and 4 than for carbons 2, 3, and 6, indicating that something more than a solvent effect was occurring. The cycloamyloses (cyclic alpha-1----4 linked D-glucose oligosaccharides which may be considered as model for an amylose helix) in water have chemical shifts for carbons 1 and 4 that are comparable to those shown by the amylodextrin complexes. It is thus proposed that the formation of a helical complex with amylodextrin results in a change in the conformation of the glycosidic linkage, which is reflected by greater downfield shifts of the signals for carbons 1 and 4, relative to those for carbons 2, 3, and 6. It was observed that differences in the ratio of the downfield shifts of C-1 and C-4 of the different amylodextrin complexes indicate differences in the degree of compactness of the helical structures. A comparison of the 13C chemical shifts of methyl alpha-D-glucoside and methyl alpha-maltoside showed that, for a molecule as small as a disaccharide, there is a conformational change about the glycosidic linkage when complexing agents are added.

Fractionation of nucleoli from auxin-treated soybean hypocotyl into nucleolar chromatin and preribosomal particles

Nucleoli from auxin-treated tissues (Glycine max L. var Wayne or Kaoshiung No. 3) were isolated and purified by Percoll density gradient centrifugation. There was a 2.1-fold increase in RNA and a 2.8-fold increase in protein after a 24-h auxin treatment per unit nucleolar DNA. More than 150 acid-soluble protein spots were associated with the auxin-treated nucleoli on two dimensional (2-D) gel electropherograms.Nucleoli from auxin-treated tissue were fractionated by suspension in 20 millimolar dithiothreitol at room temperature for 20 minutes into two distinct fractions referred to as the nucleolar chromatin and preribosomal particle fractions. The DNA:RNA:protein ratio of the chromatin fraction was 1:2.5:14. Most of RNA polymerase 1 activity and nucleolar DNA recovered in this fraction. The acid-soluble proteins in the chromatin were resolved into 32 protein spots on 2-D gel electropherogram. The most abundant spots were identified as histones.The nucleolar preribosomal particle fraction had a DNA:RNA:protein ratio of 1:24:102 and contained only trace amounts of RNA polymerase 1 activity and only 10 per cent of the nucleolar DNA. Acid-soluble proteins associated with these particles were resolved into 78 protein spots; 72 of these (acid-soluble) protein spots corresponded in 2-D gel electrophoresis to 80S cytoplasmic ribosomal proteins. Some 15 protein spots found in 80S ribosomal proteins were absent in the preribosomal particles. It seems reasonable, based on these data, that the enlargement of nucleoli after auxin treatment is primarily due to the large increase in ribosomal proteins and rRNA which accumulate and assemble in the nucleoli in the form of preribosomal particles.

Proton nuclear magnetic resonance study of an active pentapeptide fragment of ubiquitin

The aqueous solution conformation of Tyr-Asn-Ile-Gln-Lys (UB5) corresponding to positions 59-63 of the polypeptide, ubiquitin, has been investigated by proton NMR. Like the parent protein, UB5 induces nonspecifically both T and B lymphocyte differentiation. The various NH and CH resonances of this pentapeptide have been assigned, and its solution conformation has been probed through a study of chemical shift variations with pH, temperature dependence of amide hydrogen chemical shifts, vicinal NH--C alpha H and C alpha H--C beta H2 coupling constant data, and amide hydrogen-exchange rates. The latter were measured in H2O by using a combination of transfer of solvent saturation and saturation recovery NMR experiments. The data are compatible with the assumption of a highly motile dynamic equilibrium among different conformations for this peptide. The various secondary amide hydrogens remain essentially exposed to the solvent. The temperature-dependence study of the amide hydrogen chemical shifts also did not reveal any strong internal hydrogen bonds. A rotamer population analysis of tyrosine and asparagine side chains suggests that two of the rotomers are predominantly populated for each of these residues. From these results, a picture emerges of the dynamic conformation of UB5 in aqueous solution.

Solution conformation of thymopoietin32-36: a proton nuclear magnetic resonance study

The aqueous solution conformation of Arg-Lys-Asp-Val-Tyr (TP5), corresponding to positions 32-36 of the thymic hormone thymopoietin has been investigated by proton nuclear magnetic resonance (NMR). This pentapeptide fragment retains the biological activity of the parent protein, viz., induction of selective differentiation of T lymphocytes. All the observed NH and CH resonances of TP5 have been assigned, and the solution conformation of this peptide has been investigated by analysis of chemical shift variations with pH, vicinal NH-C alpha H coupling constant data, and amide hydrogen exchange rates. The latter were measured in H2O by using a combination technique consisting of the transfer of solvent saturation and saturation recovery NMR experiments. The data are compatible with the assumption of a highly motile dynamic equilibrium among different conformations for TP5. A comparison of the amide hydrogen exchange rates of the pentapeptide with that of solvated model compounds shows that Val4-NH is significantly shielded from the solvent. In addition, the chemical shift variations with pH suggest that the guanidino-N epsilon H of arginine is associated with one of the carboxylate groups. These observations provide specific boundary conditions for the construction of molecular models of the conformation(s) of TP5 in aqueous solution.

Amide hydrogen exchange rates of peptides in H2O solution by 1H nuclear magnetic resonance transfer of solvent saturation method. Conformations of oxytocin and lysine vasopressin in aqueous solution

The NH exchange rates in aqueous media of oxytocin and 8-lysine vasopressin (LVP) have been measured by using transfer of solvent saturation method. The data are consistent with a "highly motile" dynamic equilibrium between folded and highly solvated conformations. The highly-motility limit applies to the exchange of NH hydrogens of oxytocin and LVP. Folded structures are more prevalent in oxytocin than in LVP. Partial shielding is indicated for peptide hydrogens of Asn5 and perhaps also Cys6 of oxytocin and for Cys6 of LVP. It is tentatively proposed that the folded conformation of oxytocin in aqueous media may contain a parallel beta-structure in the tocinamide ring consisting of two hydrogen bonds: one between the Tyr2 C = O and Asn5 peptide NH as originally proposed for the preferred conformation of oxytocin in dimethyl sulfoxide (D. W. Urry and R. Walter), and the second between he Cys1 C = O and the Cys6 NH. In LVP the hydrogen bond between the Tyr2 C = O and Asn5 peptide NH appears to be absent. The acylic tripeptide sequences (-Pro-X-Gly-NH2) of both hormones appear to be predominantly solvated. The second-order rate constants for acid catalyzed exchange of the primary amide hydrogens of Gln4, Asn5, and Gly9 of oxytocin are consistently greater for the trans NH than for the corresponding cis NH. This observation can be rationalized in terms of mechanisms involving protonation of either the amide oxygen, or the amide nitrogen, but with limited rotation about the C - N bond.