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.

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.

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.

[Feasibility and efficacy of partial superficial parotidectomy with V-shaped incision]

Objective: To evaluate the feasibility and efficacy of partial superficial parotidectomy with V-shaped incision by comparing with the Blair incision and hairline N-shaped incision. Methods: From January 2015 to January 2016, 60 patients (47 males and 13 females, with an age range of 25- 63 years) required for superficial partial parotid gland resection were randomly divided into three groups: V-shaped incision (VI) group, Blair incision (BI) group and hairline N-shaped incision (NI) group, with 20 cases in each group.Intraoperative, postoperative and follow-up indexes were compared between three groups. Operative time and drainage volume in the surgery of tumors at different sites in VI group were compared. SPSS18.0 software was used for statistic analysis. Results: There were no statistically significant differences among the three groups in operative time, drainage volume, postoperative hospital stay, periauricular numbness, fistulas, pain score, facial palsy, and scar score at the 3rd month after surgery (P>0.05). For appearance satisfaction score at the 6th month after surgery, VI group was better than BI group or NI group, with significant differences(VI group vs. BI group: 9.00[8.00, 9.00] vs. 5.00[4.00, 5.25], χ(2)=6.629, P<0.001; VI group vs. NI group: 9.00[8.00, 9.00] vs. 7.00[6.00, 8.00], χ(2)=2.942, P=0.010; BI group vs. NI group: 5.00[4.00, 5.25] vs. 7.00[6.00, 8.00], χ(2)=-3.687, P=0.001). For tumors located in the front, upper and middle of parotid gland, there were no statistically significant differences in operative time and drainage volume between the three groups (P>0.05). For tumors located at the lower part of parotid gland, the difference in operative time between the three groups was statistically significant (F=7.278, P=0.01). With pairwise comparison, operative time in VI group was longer than that in BI group or NI group, but there was no significant difference between BI group and NI group (VI group vs. BI group: (181.00±22.89) min vs. (132.50±9.01) min, t=3.694, P=0.004; VI group vs. NI group:(181.00±22.89) min vs. (149.00±15.94) min, t=2.585, P=0.025; BIgroup vs. NI group, (132.50±9.01) min vs. (149.00±15.94) min, t=1.257, P=0.235). For tumors located at the lower part of parotid gland, the differences in intraoperative drainage volume were not statistically significant between three groups (P>0.05). There were no statistically significant differences in operative time and drainage volume in the surgery of tumors at different sites in VI group (P>0.05). Conclusions: By use of V-shaped incision for the surgery of benign parotid gland tumors, the operation time of tumors located only in the lower part of the parotid gland will be prolonged. For tumors in different sites without increasing surgical complications, this modality can get good cosmetic effect.

[High-mobility group protein 1 promotes diethylnitrosamine-induced liver cancer formation in mice by activating mitochondrial biogenesis]

Objective: To study the role of high-mobility group protein 1 (HMGB1) in the promotion of diethylnitrosamine-induced liver cancer formation in C57BL/6 mice and its mechanism. Methods: HMGB1(loxp/loxp)/Alb-Cre(+/-) were used as a liver-specific knockout (KO) of HMGB1 gene in mice. HMGB1(loxp/loxp)/Alb-Cre(-/-), HMGB1(loxp/WT)/Alb-Cre(+/-) and HMGB1(loxp/WT)/Alb-Cre(-/-) born in the same litter were wild-type mice. Six 12-day-old male WT and KO mice were separated and given a single intraperitoneal injection of diethylnitrosamine (25 mg/kg). Six months later, HE staining was used to evaluate the histopathological changes and then the incidence of liver cancer in each mice group was calculated. Serum samples were taken from each mice group to determine alanine aminotransferase levels. Immunohistochemical staining was used to detect the expression and intracellular localizations of HMGB1 protein status in tumor tissue of the two groups of mice. Western blot was used to detect the expressional condition of mitochondrial biogenesis in tumor tissue of the two groups of mice. RT-PCR was used to detect mitochondrial DNA copy number of tumor tissue and normal liver tissue in the two groups of mice. Intra and inter group data comparison was compared using t-tests and one one-way analysis of variance. Results: Compared with WT mice, the liver/body weight ratio of KO mice was decreased significantly (t = 2.634, P = 0.0225). Serum alanine aminotransferase levels in both groups of mice were increased, and the difference was not statistically significant (t = 0.4062, P = 0.6932). There were many visible gray-white nodules of different sizes on the liver surface of WT mice, and the histological type was hepatocellular carcinoma. There was no statistically significant difference in the incidence of liver cancer among different genotypes of WT mice (P > 0.05). The incidence rate of liver cancer in KO mice was significantly reduced (t = 8.521, P < 0.001). Compared with WT mice, the expression levels of HMGB1 and mitochondrial biogenesis (PGC-1α and NRF1) was significantly reduced (t = 6.238, 4.852, P = 0.0335, 0.041) in tumor tissue of KO mice. Mitochondrial DNA copy number was decreased significantly (t = 9.211, P < 0.01). Mitochondrial DNA copy number in tumor tissue of WT mice was significantly higher than that in normal liver tissue (t = 8.305, P = 0.0142). Conclusion: HMGB1 promotes the formation of diethylnitrosamine-induced liver cancer by inducing mitochondrial biogenesis.

[Efficiency analysis on functional protection of nerve plane-oriented laparoscopic total mesorectal excision]

Objective: Using previous total mesorectal excision with pelvic autonomic nerve preservation (PANP+TME) and simple total mesorectal excision (TME) without emphasis on retained nerves as control, we explore the advantages of nerve plane-oriented laparoscopic total mesorectal excision (NPO+LTME) on urinary and sexual function. Methods: A retrospective cohort study was carried out. Case inclusion criteria: (1) male patients with pathologically confirmed middle and low rectal adenocarcinoma (4 to 11 cm from the anus); (2) stage T1-2tumor; (3) normal sexual life before operation. Exclusion criteria: (1) no pathological diagnosis before surgery; (2) local recurrence or distant metastasis; (3) preoperative neoadjuvant chemoradiotherapy; (4) opensurgery and laparoscopic surgery conversionto open; (5) no follow-up data. According to the above criteria, clinical data of 173 male patients with low and middle rectal adenocarcinoma who underwent radical operation for laparoscopic rectal cancer from July 2003 to July 2018 at the Department of Gastrointestinal Surgery, Wuhan University People's Hospital were collected. According to different surgical methods, patients were divided into TME group (58 cases), PANP+TME group (63 cases) and NPO+LTME group (52 cases). There were no significant differences in the baseline data including age, body mass index and pathological examination between the 3 groups (all P>0.05). The nerve plane referred to the nerve, the adipose tissue, the extremely finecapillaries around the nerve with overlying fine membranous tissue. NPO+LTME referred to the process of laparoscopic TME guided by the nerve plane, performing in the loose connective tissue between the nerve plane and the rectal properfascia, in order to ensure the integrity of the nerve plane, and maximally protect the patient's urinary and reproductive functions. The operation time, intraoperative blood loss, urinary catheter removal time, urinary function grading, postoperative first erection time, and erectile function and ejaculation function were observed and compared among the 3 groups at 3- and 6-month after operation. Results: In the NPO+LTME group, the PANP+TME group and the TME group, the operation time was (181.9±24.5) minutes, (176.7±29.2) minutes and (137.7±16.2) minutes, respectively (F=54.868, P<0.001); the intraoperative blood lost was (6.0±1.4) ml, (6.5±1.8) ml and (12.8±4.6) ml, respectively (F=95.016, P<0.001); the time to postoperative removal of the catheter was (2.4±1.1) days, (3.7 ±1.7) days and (6.5±2.4) days, respectively (F=79.409, P<0.001); the first postoperative erection time was (1.6±0.6) days, (8.9±2.7) days and (15.9±6.8) days (F=177.677, P<0.001), respectively, whose differences were all statistically significant (all P<0.01). In comparison of urinary function grading, the proportion of grade I (normal function, no urinary dysfunction) in the NPO+LTME, the ANP+TME group and the TME group was 84.1% (53/63), 39.7% (23/58) and 19.2% (10/52), respectively, and the difference was statistically significant (H=52.915, P<0.001). At postoperative 3- and 6-month, proportion of patients with grade I erectile function (normal erectile function) was 77.8% (49/63) and 85.7% (54/63), 44.8% (26/58) and 53.4% (31/58), 28.8% (15/52) and 48.1% (25/52) in the NPO+LTME group, the PANP+TME group, and the TME group, respectively. The differences were statistically significant (H=91.709, P<0.001; H=79.692, P<0.001). The proportion of patients with grade I ejaculation function (with ejaculation, no abnormalities in routine semen examination before and after surgery) at 3- and 6-month after surgery in the NPO+LTME group, the PANP+TME group and the TME group was 82.5% (52/63) and 87.3% (55/63), 53.4% (31/58) and 60.3% (35/58), 28.8% (15/52) and 46.1% (24/52), respectively. The differences were statistically significant as well (H=86.543, P<0.001; H=78.667, P<0.001). Patients in the NPO+LTME group had no grade III erections and ejaculation disorders. Conclusion: The surgical procedure of NPO+LTME can promote the recovery of postoperative neurological function and preserve urination and sexual function better.

Effectiveness of external fixator combined with T-plate internal fixation for the treatment of comminuted distal radius fractures

This study compared the efficacy between external fixator combined with palmar T-plate internal fixation and simple plate internal fixation for the treatment of comminuted distal radius fractures. A total of 61 patients classified as type C according to the AO/ASIF classification underwent surgery for comminuted distal radius fractures. There were 54 and 7 cases of closed and open fractures, respectively. Moreover, 19 patients received an external fixator combined with T-plate internal fixation, and 42 received simple plate internal fixation. All patients were treated successfully during 12-month postoperative follow-up. The follow-up results show that the palmar flexion and dorsiflexion of the wrist, radial height, and palmar angle were significantly better in those treated with the external fixator combined with T-plate compared to those treated with the simple plate only (P < 0.05); however, there were no significant differences in radial-ulnar deviation, wrist range of motion, or wrist function score between groups (P > 0.05). Hence, the effectiveness of external fixator combined with T-plate internal fixation for the treatment of comminuted distal radius fractures was satisfactory. Patients sufficiently recovered wrist, forearm, and hand function. In conclusion, compared to the simple T-plate, the external fixator combined with T-plate internal fixation can reduce the possibility of the postoperative re-shifting of broken bones and keep the distraction of fractures to maintain radial height and prevent radial shortening.

Activated human hydroxy-carboxylic acid receptor-3 signals to MAP kinase cascades via the PLC-dependent PKC and MMP-mediated EGFR pathways

BACKGROUND AND PURPOSE 3-Hydroxy-octanoate, recently identified as a ligand for, the orphan GPCR, HCA(3), is of particular interest given its ability to treat lipid disorders and atherosclerosis. Here we demonstrate the pathway of HCA(3)-mediated activation of ERK1/2. EXPERIMENTAL APPROACH Using CHO-K1 cells stably expressing HCA(3) receptors and A431 cells, a human epidermoid cell line with high levels of endogenous expression of functional HCA(3) receptors, HCA(3)-mediated activation of ERK1/2 was measured by Western blot. KEY RESULTS HCA(3)-mediated activation of ERK1/2 was rapid, peaking at 5 min, and was Pertussis toxin sensitive. Our data, obtained by time course analyses in combination with different kinase inhibitors, demonstrated that on agonist stimulation, HCA(3) receptors evoked ERK1/2 activation via two distinct pathways, the PLC/PKC pathway at early time points (≤ 2 min) and the MMP/ epidermal growth factor receptor (EGFR) transactivation pathway with a maximum response at 5 min. Furthermore, our present results also indicated that the βγ-subunits of the G(i) protein play a critical role in HCA(3)-activated ERK1/2 phosphorylation, whereas β-arrestins and Src were not required for ERK1/2 activation. CONCLUSIONS AND IMPLICATIONS We have described the molecular mechanisms underlying the coupling of human HCA(3) receptors to the ERK1/2 MAP kinase pathway in CHO-K1 and A431 cells, which implicate the G(i) protein-initiated, PLC/PKC -and platelet-derived growth factor receptor/EGFR transactivation-dependent pathways. These observations may provide new insights into the pharmacological effects and the physiological functions modulated by the HCA(3)-mediated activation of ERK1/2.

Surface geometric and electronic structures of BaFe2As2(001)

BaFe2As2 exhibits properties that are characteristic of the parent compounds of the newly discovered iron (Fe)-based high-T(C) superconductors. By combining real-space imaging of scanning tunneling microscopy and spectroscopy (STM+STS) with momentum-space quantitative low-energy electron diffraction (LEED), we have identified the surface plane of cleaved BaFe2As2 crystals as the As terminated Fe-As layer-the plane where superconductivity occurs. LEED and STM+STS data on the BaFe2As2(001) surface indicate an ordered arsenic (As) terminated metallic surface without reconstruction or lattice distortion. It is surprising that STM images the different Fe-As orbitals associated with the orthorhombic structure, but not the As atoms in the surface plane.

Role of lateral alkyl chains in modulation of molecular structures on metal surfaces

We use low energy electron diffraction, scanning tunneling microscopy, first-principles density-functional theory, and molecular mechanics calculations to analyze the adsorption and growth of quinacridone derivatives (QA) with alkyl chains of 4 and 16 carbon atoms on a Ag(110) substrate. Surprisingly, we find that the alkyl chains determine the orientation of the molecular overlayers. While the interaction of QA and the Ag substrate is primarily due to chemical bonding of oxygen to the silver substrate, determining the molecular orientation and preferred adsorption site, the intermolecular arrangement can be adjusted via the length of alkyl chains. We are thus able to fabricate uniform QA films with very well controlled physical properties.

Selective analysis of molecular states by functionalized scanning tunneling microscopy tips

Selective analysis of molecular states in scanning tunneling microscopy (STM) has so far been achieved in a few cases by tuning the bias range of the STM in high-resolution measurements. Correspondingly, perylene adsorbed in a close-packed monolayer on Ag(110) is imaged mainly through the pi states of the molecule. By contrast, functionalizing the STM tip with a perylene molecule leads to a mismatch between the energy levels of the STM tip and the molecule adsorbates and, instead, images only the metal states of the underlying silver surface. The observation opens a route for better energy selectivity in electron transport measurements through organic interfaces.

Effects of bile acids on 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine-induced aberrant crypt foci and DNA adduct formation in the rat colon

The effects of deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA) on 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-induced aberrant crypt foci (ACF) in the rat colon were examined. The effect of these bile acids on DNA adduct formation by PhIP in the colon was then analyzed, since the main action of PhIP is the formation of DNA adducts and subsequent gene mutations. For the ACF study, male F344 rats were administered PhIP-HCl (75 mg/kg, 10 doses) by gavage, and a diet containing bile acid (0.4% DCA or UDCA) was provided from 3 days before the first dose of PhIP for 8 weeks. The mean number of ACF per colon of DCA, UDCA and controls were 9.9, 2.4 and 5.5, respectively. The ACF number was significantly increased by DCA and decreased by UDCA (P<0.001). To examine the effect of bile acids on DNA adduct formation, male F344 rats were fed a diet supplemented with bile acids (0.1 or 0.4% of DCA and UDCA) 7 days prior to the PhIP administration. All rats were administered a single dose of PhIP-HCl (50 mg/kg) by gavage and sacrificed 48 hours later. DNA adduct levels of the 0.1% UDCA, 0.1% DCA and controls were 2.93 (adducts/10(7) nucleotides), 2.65 and 1.10, respectively. Those of 0.4% UDCA, 0.4% DCA and controls were 1.64, 1.30 and 1.00, respectively. The PhIP-DNA adduct level was significantly increased by administration of 0.1% UDCA, 0.1% DCA (P<0.05) and 0.4% UDCA (P<0.01). The increasing effect of both DCA and UDCA on PhIP-induced DNA adduct formation was unexpected, and was not directly associated with ACF formation.

Identification of GABA(B) receptor in rat testis and sperm

gamma-Aminobutyric acid (GABA) can mimic and potentiate the action of progesterone in initiating the acrosome reaction (AR) of mammalian sperm, indicating that sperm contain receptors for GABA. This contention was validated by identifying the receptor (R) subtype, GABA(A)R, in mammalian sperm. In the present study a second subtype, GABA(B)R, was identified in rat testis and sperm. Total RNAs of rat testis and sperm were prepared and used as template to synthesize the respective cDNAs by the RT-PCR method. Two splice variants of the cDNA coding GABA(B)R1 (GABA(B)R1a and GABA(B)R1c) and GABA(B)R2 were identified. Extracts of rat testis, spermatogenic cells and sperm contained two proteins with estimated molecular sizes of 130 and 100 kDa, corresponding to GABA(B)R1a and GABA(B)R1c/lb, respectively, determined by Western blot using polyclonal anti-GABA(B)R1 antibody. By an indirect immunofluorescence technique, GABA(B)R1 was located on the head of rat sperm. The present finding is the first direct demonstration that mammalian sperm contain GABA(B)R.

Identification of gamma-aminobutyric acid transporter (GAT1) on the rat sperm

Some recent studies indicated that GABAergic system is involved in mammalian sperm acrosome reaction (AR), but direct evidence pertaining to the expression of gat1 in mammalian sperm is not yet demonstrated. In this study, we evaluated the presence of 67kDa GAT1 protein and mRNA in rat testis by Western blotting and reverse transcription-polymerase chain reaction. Meanwhile, immunohistochemical and immunofluorescent analyses also identified GAT1 protein on the elongated spermatid and sperm. These results indicated that rat testis is a novel site of gat1 expression. Further studies should be taken to explore the role of GAT1 protein on sperm acrosome reaction.

The genotype and epigenotype synergize to diversify the spatial pattern of expression of the imprinted H19 gene

Little is known of how the genetic background effects the phenomenon of genomic imprinting. The H19 gene belongs to a cluster of imprinted genes on human chromosome 11. Here we show that the alternative splicing of a human H19 transcript is genotype-specific. Moreover, this variant transcript, which lacks exon 4, is either not found at all, is widely expressed or is confined to extra-villous cytotrophoblasts in first trimester placenta, depending on a combination of the genotype and the sex of the transmitting parent.

The H19 transcript is associated with polysomes and may regulate IGF2 expression in trans

The imprinted H19 gene produces a fully processed transcript that does not exhibit any conserved open reading frame between mouse and man. Although transcriptional control elements associated with the mouse H19 locus have been shown to control the neighboring Igf2 gene in cis, the prevailing view is that the cytoplasmic H19 transcript does not display any function. In contrast to earlier reports, we show here that the H19 transcript is associated with polysomes in a variety of cell types, in both mouse and man. A possible trans-function of the H19 gene is suggested by a reciprocal correlation in trans between cytoplasmic H19 and IGF2 mRNA levels, as well as IGF2 mRNA translatability. We discuss these results in terms of their challenge to the prevailing dogma on the function of the enigmatic H19 gene, as well as with respect to the ontogeny of the Beckwith-Wiedemann syndrome, and propose that the human H19 gene is an antagonist of IGF2 expressivity in trans.

Expression of proliferating cell nuclear antigen(PCNA) in biopsy and autopsy specimens of gastric carcinoma

Although proliferating cell nuclear antigen (PCNA) is known to be an indicator of malignant potential in tumors, the biological and clinicopathological significance of PCNA in tumor tissue is controversial.

METHODS

Immunohistochemical expression of PCNA was examined in 58 gastric carcinoma tissues obtained at autopsy to test the clinicopathological significance. In addition, in 24 of the 58 tumor tissues we compared immunohistochemical expression of PCNA in biopsy and autopsy specimens from the same patient in order to know whether the proliferating activity of tumor cells is stationary from the early stage to the end of tumor growth.

RESULTS

1. PCNA was undetectable in some tumor tissues (12.5% in biopsy and 10.3% in autopsy specimens). 2. the frequency of PCNA positive cases and labeling index (LI) (%) of PCNA in tumor tissues were not significantly different between biopsy and autopsy specimens. 3. the intensity of PCNA reaction was not related to prognosis. 4. PCNA positive cases and LI did not correlate with survival condition.

CONCLUSION

It is hard to say whether PCNA is a reliable indicator in predicting malignancy and prognosis of gastric cancer.