Erratum: Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande [Phys. Rev. Lett. 130, 031802 (2023)].

This corrects the article DOI: 10.1103/PhysRevLett.130.031802.

Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande.

We report a search for cosmic-ray boosted dark matter with protons using the 0.37 megaton×years data collected at Super-Kamiokande experiment during the 1996-2018 period (SKI-IV phase). We searched for an excess of proton recoils above the atmospheric neutrino background from the vicinity of the Galactic Center. No such excess is observed, and limits are calculated for two reference models of dark matter with either a constant interaction cross section or through a scalar mediator. This is the first experimental search for boosted dark matter with hadrons using directional information. The results present the most stringent limits on cosmic-ray boosted dark matter and exclude the dark matter-nucleon elastic scattering cross section between 10^{-33}cm^{2} and 10^{-27}cm^{2} for dark matter mass from 1 MeV/c^{2} to 300 MeV/c^{2}.

Sugar-responsible elements in the promoter of a gene for beta-amylase of sweet potato.

Expression of genes coding for sporamin and beta-amylase, the two most abundant proteins in storage roots of sweet potato, is coordinately inducible in atypical vegetative tissues by sugars. A sweet potato gene for beta-amylase (beta-Amy) with introns as well as a beta-Amy::GUS fusion gene composed of the beta-Amy promoter and the GUS coding sequence, both showed sugar-inducible expression in leaves of transgenic tobacco which occurred via a hexokinase-independent pathway. Analyses using various 5'-terminal and internal deletions of the beta-Amy promoter indicated that truncated promoters of beta-Amy containing a sequence between -901 and -820, relative to the transcription start site, and the basic promoter region can confer sugar-inducible expression. This 82 bp region contained the TGGACGG sequence that plays an essential role in the sugar-inducible expression of the truncated promoter of the sporamin gene. Deletion or base substitutions of this element in the truncated beta-Amy promoter abolished the sugar-inducible expression, the results suggesting that the TGGACGG element plays an important role in the coordinate induction of expression of genes for beta-amylase and sporamin by sugars.

The mitogenic activity of hepatocyte growth factor on rat hepatocytes is dependent upon endogenous transforming growth factor-alpha.

Both transforming growth factor-alpha (TGF-alpha) and hepatocyte growth factor (HGF) induce DNA synthesis in hepatocytes in vitro and in vivo. Hepatic and circulating levels of HGF have been reported to increase before an increase in TGF-alpha levels in several rat models of liver regeneration. In addition, serum TGF-alpha levels increase after an increase in serum HGF levels in patients with either partial hepatectomy or acute hepatitis. In this study, we investigate the significance of TGF-alpha in hepatocyte proliferation. TGF-alpha contents and DNA synthesis in cultured rat hepatocytes increased in response to HGF addition to the culture medium in a dose-related manner. These increases were suppressed by the addition of anti-sense TGF-alpha mRNA oligonucleotide. Furthermore, the addition of anti-TGF-alpha rabbit IgG suppressed the increase in DNA synthesis. When the anti-TGF-alpha antibody was administered to rats after partial hepatectomy, the number of mitotic hepatocytes was reduced in comparison to rats treated with normal rabbit IgG. These results were observed even though hepatic HGF levels were increased equally in rats given either anti-TGF-alpha antibody or normal rabbit IgG. Our results suggest that HGF stimulates TGF-alpha production in rat hepatocytes, and that the mitogenic activity of HGF depends on endogenous TGF-alpha activity.

Lysophosphatidic acid enhances collagen gel contraction by hepatic stellate cells: association with rho-kinase.

We studied the effect of lysophosphatidic acid (LPA) on collagen gel contraction by cultured rat hepatic stellate cells (HSCs) in association with the function of Rho-kinase, one of the target molecules of small GTPase Rho. Binding studies showed a single class-binding site of LPA on HSCs. LPA enhanced the contraction of a collagen lattice seeded with HSCs. LPA increased the number of HSCs with polygonal morphology that contained actin stress fibers, and enhanced the phosphorylation of myosin light chain and the assembly of focal adhesion kinase and RhoA around fibronectin-coated beads seeded on HSCs. The electric cell-substrate impedance sensor system showed that LPA enhanced adhesion of HSC to extracellular substrate. All the effects of LPA were suppressed by Y-27632, Rho-kinase inhibitor. These data support the notion that LPA is involved in modulating HSC morphology, its attachment to surrounding extracellular matrix and its contraction by a mechanism involving Rho-kinase.

Experimental study on liver regeneration after simultaneous partial hepatectomy and pancreatectomy.

In this study, we performed hepatectomy and pancreatectomy to assess the physiological contribution of the pancreas, especially in terms of endocrine function to hepatic regeneration. Group 1 Wistar rats underwent 70% hepatectomy and group 2 rats underwent 70% hepatectomy plus 50% pancreatectomy. The time course assessment of liver regeneration rates obtained by Fishback's formula demonstrated a difference in rates between the two groups as early as day 3 or day 7 after surgery. Since levels of both PCNA-positive cells and serum transforming growth factor-alpha (TGF-alpha) were significantly higher in the hepatectomy only group, we could prove the difference of liver regeneration between the two groups. We have concluded that pancreatectomy retards the liver regeneration initiation processes occurring from 24 h to 3 days after evisceration. Glucagon-insulin molar ratios most significantly differed between the two groups 3 days after evisceration in the present study. This result was due to increased glucagon level of group 2 at day 3 after evisceration. Our findings suggest that 50% partial pancreatectomy inhibits the rate of hepatic regeneration, thereby altering the supply of pancreatic hormones, especially glucagon.

Transforming growth factor alpha levels in liver and blood correlate better than hepatocyte growth factor with hepatocyte proliferation during liver regeneration.

Transforming growth factor alpha (TGFalpha) and hepatocyte growth factor (HGF) are mitogens for hepatocytes in vitro and in vivo, produced by hepatocytes or nonparenchymal cells such as stellate cells in the liver. It is still uncertain whether TGFalpha and HGF are essential for liver regeneration. To assess the role of these growth factors in liver regeneration, their circulating and hepatic levels were studied in various rat models of liver regeneration. Hepatic and plasma HGF levels were increased with increased number of mitotic hepatocytes in rats after partial hepatectomy or carbon tetrachloride intoxication. However, hepatic HGF levels were decreased despite an increased number of mitotic hepatocytes and increased or unchanged plasma HGF levels in rats given phenobarbital and in rats after dimethylnitrosamine intoxication, which can induce hepatic necrosis after apoptosis of hepatic stellate cells. In contrast, hepatic and serum TGFalpha levels were increased in all of the models. In sham-operated rats with no increased number of mitotic hepatocytes, hepatic and circulating levels of HGF were increased, whereas those levels of TGFalpha were unchanged. The results indicate that TGFalpha levels in liver and blood more closely correlate with hepatocyte mitogenesis than HGF levels.

Enhancement of albumin production by hepatocyte growth factor in rat hepatocytes: distinction in mode of action from stimulation of DNA synthesis.

Hepatocyte growth factor (HGF) has been shown to enhance albumin production as well as stimulate DNA synthesis in hepatocytes. The mode of action of HGF in exerting both effects is to be elucidated. We previously observed that hepatocyte proliferation occurred in normal rats given recombinant human HGF (rhHGF) intravenously. When rats received rhHGF similarly, serum albumin levels were significantly increased compared to controls. In primary culture of rat hepatocytes, albumin concentration in culture medium was significantly increased by rhHGF added at 24 h of culture compared to controls, increasing with time of culture. This effect of rhHGF was dose-related. When actinomycin D was added to the medium, the albumin concentration was reduced in a dose-related manner, but its enhancement by rhHGF was maintained. Albumin mRNA levels were not increased by rhHGF. When rhHGF was added similarly to the medium, immunocytochemically positive hepatocytes for 5-bromo-2'-deoxyuridine (BrdU) incorporation appeared 30 h later. Of these labeled hepatocytes, 12.5% were concomitantly stained for albumin. In contrast, albumin-positive hepatocytes were seen in 77% of BrdU-non-labeled hepatocytes (p<0.01). We conclude that HGF may enhance albumin production through post-transcriptional regulation in non-proliferating hepatocytes, but not in proliferating hepatocytes.

Serum transforming growth factor-alpha level can be a parameter for evaluating liver regeneration after partial hepatectomy in patients with liver cancer.

Sensitive and reliable laboratory parameters are necessary to evaluate the degree of liver regeneration serially in patients after partial hepatectomy for liver cancer. We evaluated the serum levels of transforming growth factor-alpha (TGF-alpha) and hepatocyte growth factor (HGF), both of which are potent mitogens for hepatocytes, in 22 hepatectomized patients with liver cancer: 10 patients with hepatocellular carcinoma and 12 patients with metastatic liver tumors. Ten patients who underwent laparotomy for nonhepatic surgery were also studied as surgical controls. The serum TGF-alpha and HGF levels were measured by sandwich enzyme-linked immunosorbent assay techniques. Both the serum TGF-alpha and HGF levels increased after partial hepatectomy. However, there was no correlation between the levels of TGF-alpha and HGF. The maximal level of TGF-alpha achieved in each case correlated significantly with the resected liver volume and the increased volume of the remaining liver. Hepatocyte growth factor showed no such correlations. After nonhepatic surgery, the HGF level also increased significantly, while the TGF-alpha level did not. These results suggest that the serum TGF-alpha level varies depending on the regenerative stimulus to the liver, and that its increase corresponds with the degree of liver regeneration that occurs in patients after partial hepatectomy for liver cancer. In contrast, it is unlikely that the serum HGF level reflects liver regeneration. In conclusion, the serum TGF-alpha level can be used as a parameter for evaluating liver regeneration in patients who have undergone partial hepatectomy.

Transforming growth factor-alpha (TGF alpha)-producing gastric carcinoma with acanthosis nigricans: an endocrine effect of TGF alpha in the pathogenesis of cutaneous paraneoplastic syndrome and epithelial hyperplasia of the esophagus.

A case of well-differentiated adenocarcinoma (Borrmann type 3) of the stomach in a 76-year-old man associated with the typical skin manifestations of acanthosis nigricans and with multiple protruding lesions showing epithelial hyperplasia of the esophagus is reported. The advanced tumor was located in the cardiac region of the stomach, and measured approximately 8 cm in diameter, with partial invasion to the esophagus. The associated cutaneous lesions were characterized by hyperpigmentation and by protruding verrucous papules on the torso, head, face, neck, upper extremities, perineum, and inguinal region. Histologically, the protruding skin lesions showed keratinocytes proliferation throughout the epidermis, resulting in diffuse hyperkeratosis, papillomatosis, and acanthosis of the skin. Immunohistological analysis showed coexpression of transforming growth factor alpha (TGF-alpha) and epidermal growth factor (EGF) receptors in the tumor from the stomach. It is reasonable to conclude from this evidence that gastric carcinoma cells secrete TGF alpha in an autocrine for auto-stimulation. EGF receptor expression was also noted on the papillomatous hyperplasia of the cutaneous lesion. Serum level of TGF alpha, determined by an enzyme-linked immunosorbent assay, was high (144 pg/ml; normal, 22.0 +/- 16 pg/ml (Mean +/- SD)). Serum TGF alpha abruptly decreased to 49 pg/ml on day 7 after the total gastrectomy, and then gradually increased to 77 pg/ml within 28 days. Amelioration of the cutaneous lesions and the protruding lesions in the esophagus was observed after surgical resection of the gastric carcinoma. This suggests that the TGF alpha stimulates the proliferation of keratinocytes involved with EGF receptor. Large amounts of circulating TGF alpha in the blood over a long period released by the primary tumor seem to act as an endocrine-like mechanism causing epidermal and esophageal epithelial cells to proliferate. There is a possible link in the pathogenesis of the acanthosis nigricans as a cutaneous paraneoplastic syndrome, and epithelial hyperplasia of the esophagus.

Serum transforming growth factor alpha level as a marker of hepatocellular carcinoma complicating cirrhosis.

BACKGROUND: Transforming growth factor alpha (TGF alpha) is alleged to play a role in malignant progression as well as normal cell growth in an autocrine manner and its serum levels have been reported to increase during this progression. Most hepatocellular carcinomas (HCC) develop in cirrhotic livers in which hepatocyte necrosis and regeneration prevail. The significance of serum TGF alpha levels in the diagnosis of HCC complicating cirrhosis should be clarified. METHODS: One hundred twenty-four patients with cirrhosis were studied, 80 with HCC (HCC) patients and 44 without (LC) patients. There was no difference in clinical features between the two groups. One hundred eighty-two healthy adults were also studied as controls. Serum TGF alpha levels were measured by enzyme-linked immunosorbent diffusion assay (ELISA). RESULTS: Serum TGF alpha levels were significantly higher in HCC patients than in healthy adults or LC patients (mean +/- SD: 45 +/- 40 vs. 21 +/- 15 or 25 +/- 19 pg/ml, respectively). In LC patients, serum TGF alpha levels were significantly correlated with serum albumin and total bilirubin levels (r = -0.44 and 0.32, respectively). When the cutoff level was defined as 25 pg/ml from receiver operating characteristic curve, sensitivity and specificity for the diagnosis of HCC in the presence of cirrhosis were 69% and 66%, respectively. Serum TGF alpha levels were decreased after successful treatment for HCC in 60% of the HCC patients. Serum TGF alpha levels showed no correlation with serum alpha-fetoprotein levels; the levels were greater than 25 pg/ml in 67% of the HCC patients whose serum alpha-fetoprotein levels were within 20 ng/ml. CONCLUSION: Serum TGF alpha levels may provide useful information for the diagnosis of HCC developing in the presence of cirrhosis.

Liver regeneration in fulminant hepatitis as evaluated by serum transforming growth factor alpha levels.

Transforming growth factor alpha (TGF alpha) is supposed to act as a mitogen for hepatocytes in an autocrine manner in vitro and in vivo. Retarded liver regeneration is a possible reason for poor prognosis of fulminant hepatitis (FH). We analyzed serum TGF alpha levels in patients with FH and patients with acute nonfulminant hepatitis (AH). Also, the relation of those levels to serum hepatocyte growth factor (HGF) levels and their changes after glucagon-insulin (G-I) therapy were studied. Maximal serum TGF alpha levels achieved in each case after admission until recovery from disease or death were correlated positively with maximal serum alanine transaminase (ALT) and total bilirubin levels in patients with AH, but negatively with maximal total bilirubin levels in patients with FH. Maximal serum TGF alpha levels in patients with FH were significantly higher in survivors than in nonsurvivors. Maximal serum HGF levels were positively correlated with maximal serum TGF alpha levels in patients with AH, but not in patients with FH. Multiple regression analysis indicated that G-I therapy was related to the increment of serum TGF alpha levels in patients with FH. These results suggest that serum TGF alpha levels are increased in accordance with liver regeneration after necrosis in patients with AH, but such liver regeneration may be retarded, depending on the extent of liver damage in patients with FH. G-I therapy seems to stimulate liver regeneration after liver damage. The possible contribution of TGF alpha and HGF to liver regeneration merits consideration for recovery from AH.

Use of prostaglandin I2 analog in treatment of massive hepatic necrosis associated with endothelial cell injury and diffuse sinusoidal fibrin deposition.

Endothelial cell damage causes massive hepatic necrosis as a result of fibrin deposition in the hepatic sinusoids. When a stable analog of prostaglandin I2, beraprost sodium, was administered to rats given either dimethylnitrosamine, carbon tetrachloride, or endotoxin following Corynebacterium parvum administration, the hepatic necrosis produced in each was attenuated, but to a greater extent in the dimethylnitrosamine and endotoxin/Corynebacterium parvum models, where fibrin deposition in the hepatic sinusoids occurs, as compared to the carbon tetrachloride model, where such fibrin deposition does not occur. Beraprost sodium reduced the expected increase of portal venous pressure in the endotoxin/Corynebacterium parvum model without affecting plasma thrombin-antithrombin III complex levels. Beraprost sodium also significantly reduced cell killing of both isolated rat hepatocytes and hepatic sinusoidal endothelial cells exposed to tert-butyl hydroperoxide when compared to controls. Beraprost sodium could prove to be a therapeutic candidate for the treatment of hepatic necrosis, particularly in cases associated with fibrin deposition in the hepatic sinusoids because of its fibrin clot-clearing action.

Regulating factors of liver regeneration after hepatectomy.

The factors regulating liver regeneration were studied by measuring changes in the liver volume and serum hepatocyte growth factor (HGF) levels after hepatectomy. Changes in the liver volumes were studied in 68 hepatectomized patients, including (A) hepatoma patients who had chronic hepatitis or liver cirrhosis (n = 44) and (B) metastatic liver cancer patients who had normal liver parenchyma (n = 24). The hepatic volume increased by 13.8% of the remnant hepatic volume in group A and by 49.1% in group B. The examined factors included the percentage of resected liver volume (%RLV) and the results of laboratory tests. Regression analysis showed that in group A, both %RLV (beta = 0.46) and the serum total bilirubin (T-Bil) level (beta = -0.33) correlated significantly with the extent of liver regeneration and that in group B, only %RLV (beta = 0.78) correlated significantly with the regeneration. Serum HGF levels after hepatectomy were studied in 21 hepatectomized patients, including 11 hepatoma patients and 10 patients with some types of metastatic liver cancer. Serum HGF levels increased significantly after surgery in all 21 patients. Regression analysis, however, showed that the change in HGF was related to liver cirrhosis (beta = 0.46) and to the maximal postoperative T-Bil level (beta = 0.51) but not to the extent of liver regeneration after hepatectomy. These results suggest that liver regeneration is regulated primarily by factors relating to the percentage of the resected liver parenchyma and that serum HGF levels do not directly relate to liver regeneration after surgery.

Stimulation of liver growth by exogenous human hepatocyte growth factor in normal and partially hepatectomized rats.

Human hepatocyte growth factor stimulates DNA synthesis by cultured rat hepatocytes. When human hepatocyte growth factor prepared from the culture medium of human embryonic lung fibroblasts was intravenously injected into normal rats and rats after 70% hepatectomy, it was detected in hepatocytes but not in nonparenchymal cells isolated 30 min after injection. Similar injections of human hepatocyte growth factor at 2-hr intervals for 10 hr significantly increased hepatic DNA content in normal rats at 48 hr, with increased hepatic content of putrescine, the essential polyamine for hepatic DNA synthesis after 70% hepatectomy, and activities of catalytic enzymes of putrescine synthesis at 6 hr almost to the levels in rats after 70% hepatectomy. Those levels in rats after 70% hepatectomy were further enhanced by similar injections of human hepatocyte growth factor starting immediately after surgery. Increased hepatic DNA content in normal rats and rats after 70% hepatectomy was also seen with recombinant human hepatocyte growth factor to a greater extent compared with that seen with human hepatocyte growth factor. In normal rats given recombinant human hepatocyte growth factor, 5-bromo-2'-deoxyuridine-labeled and mitotic hepatocytes were significantly increased in number at 26 hr but not at 48 hr. We conclude that exogenous human hepatocyte growth factor acts as a trigger and a promoter of liver growth to increase hepatic putrescine production in rats. Recombinant human hepatocyte growth factor is more potent than human hepatocyte growth factor in this action.

Serum levels of transforming growth factor-alpha in patients after partial hepatectomy as determined with an enzyme-linked immunosorbent assay.

A sandwich enzyme-linked immunosorbent assay for measuring serum transforming growth factor-alpha levels was developed with monoclonal IgM and polyclonal IgG antihuman transforming growth factor-alpha antibodies and a system to amplify the activity of the conjugated enzyme. The assay detected serum transforming growth factor-alpha levels as low as 5 pg/ml. Serum transforming growth factor-alpha levels were below the detection limit of the assay in 19% of healthy adults, with a mean (+/- S.D.) detectable level of 22.0 +/- 16.7 pg/ml. In 13 patients who underwent partial hepatectomy, serum transforming growth factor-alpha levels were determined serially after surgery. The levels were increased within 28 days of surgery in all the patients, with a mean maximal level of 118.2 +/- 90.8 pg/ml. The maximal level achieved in each case correlated significantly with the resected volume of the liver and the increased volume of the remaining liver 28 days after hepatectomy (r = 0.59, p < 0.05, and r = 0.71, p < 0.005, respectively). In contrast, serum transforming growth factor-alpha levels showed no increase after laparotomy for nonhepatic surgery. Serum transforming growth factor-alpha levels may vary depending on the regenerative stimulus and reflect the degree to which liver regeneration will occur in patients after partial hepatectomy.

Serum hepatocyte growth factor levels in hepatectomized and nonhepatectomized surgical patients.

Serum hepatocyte growth factor levels were measured in hepatectomized and nonhepatectomized surgical patients. The levels were significantly increased and reached a maximum within 7 days after surgery in both groups, returning to preoperative levels 28 days after partial hepatectomy and 7 days after other operations. Multiple regression analysis showed that such maximal hepatocyte growth factor levels were significantly related to having liver cirrhosis and postoperative maximal serum total bilirubin and alanine aminotransferase levels and peripheral white blood cell counts in the hepatectomized group and to postoperative maximal peripheral white blood cell counts and serum C-reactive protein levels in the nonhepatectomized group. However, the levels showed no relation to the resected liver volume and increment of the remaining liver volume 28 days after partial hepatectomy. It is concluded that serum hepatocyte growth factor levels were increased after partial hepatectomy in association with hepatocellular dysfunction and necrosis and systemic inflammation. It is unlikely that the increase was related to liver regeneration.

Hepatocyte membrane stabilization by prostaglandins E1 and E2: favorable effects on rat liver injury.

When prostaglandin (PG) E1 was continuously administered to rats from 24 hours before giving a dose of carbon tetrachloride, deranged serum glutamic pyruvic transaminase levels and prothrombin time were significantly reduced 12 hours after intoxication compared with controls. A similar effect of PGE1 was seen at 24 hours in D-galactosamine-intoxicated rats. Liver histology showed a comparable attenuation of injury in these rats. These results were consistent with reported effects of PGE2, suggesting that both prostaglandins may share a common pathway in protection against liver injury. When PGE1 or 16,16'-dimethyl PGE2 was added to the medium of primary cultured rat hepatocytes, lipid peroxidation-dependent killing of the cells by tert-butyl hydroperoxide was significantly attenuated without affecting the extent of malondialdehyde accumulation compared with controls. Both prostaglandins significantly reduced the extent of increased plasma membrane microviscosity of these cells assessed by 1-[4-(trimethyl-ammonio)phenyl]-6-phenyl-1,3,5-hexatriene. PGE1 and PGE2 may possess cytoprotective effects on liver parenchymal cells through stabilization of membrane microviscosity, which may contribute to protection against liver injury.