Autocrine phosphatase PDP2 inhibits ferroptosis by dephosphorylating ACSL4 in the Luminal A Breast Cancer

Phosphatases can dephosphorylate phosphorylated kinases, leading to their inactivation, and ferroptosis is a type of cell death. Therefore, our aim is to identify phosphatases associated with ferroptosis by analyzing the differentially expressed genes (DEGs) of the Luminal A Breast Cancer (LumABC) cohort from the Cancer Genome Atlas (TCGA). An analysis of 260 phosphatase genes from the GeneCard database revealed that out of the 28 DEGs with high expression, only the expression of pyruvate dehydrogenase phosphatase 2 (PDP2) had a significant correlation with patient survival. In addition, an analysis of DEGs using gene ontology, Kyoto Encyclopedia of Genes and Genomes and gene set enrichment analysis revealed a significant variation in the expression of ferroptosis-related genes. To further investigate this, we analyzed 34 ferroptosis-related genes from the TCGA-LumABC cohort. The expression of long-chain acyl-CoA synthetase 4 (ACSL4) was found to have the highest correlation with the expression of PDP2, and its expression was also inversely proportional to the survival rate of patients. Western blot experiments using the MCF-7 cell line showed that the phosphorylation level of ACSL4 was significantly lower in cells transfected with the HA-PDP2 plasmid, and ferroptosis was correspondingly reduced (p < 0.001), as indicated by data from flow cytometry detection of membrane-permeability cell death stained with 7-aminoactinomycin, lipid peroxidation, and Fe2+. Immunoprecipitation experiments further revealed that the phosphorylation level of ACSL4 was only significantly reduced in cells where PDP2 and ACSL4 co-precipitated. These findings suggest that PDP2 may act as a phosphatase to dephosphorylate and inhibit the activity of ACSL4, which had been phosphorylated and activated in LumABC cells. Further experiments are needed to confirm the molecular mechanism of PDP2 inhibiting ferroptosis.

Gankyrin inhibits ferroptosis through the p53/SLC7A11/GPX4 axis in triple-negative breast cancer cells

Gankyrin is found in high levels in triple-negative breast cancer (TNBC) and has been established to form a complex with the E3 ubiquitin ligase MDM2 and p53, resulting in the degradation of p53 in hepatocarcinoma cells. Therefore, this study sought to determine whether gankyrin could inhibit ferroptosis through this mechanism in TNBC cells. The expression of gankyrin was investigated in relation to the prognosis of TNBC using bioinformatics. Co-immunoprecipitation and GST pull-down assays were then conducted to determine the presence of a gankyrin and MDM2 complex. RT-qPCR and immunoblotting were used to examine molecules related to ferroptosis, such as gankyrin, p53, MDM2, SLC7A11, and GPX4. Additionally, cell death was evaluated using flow cytometry detection of 7-AAD and a lactate dehydrogenase release assay, as well as lipid peroxide C11-BODIPY. Results showed that the expression of gankyrin is significantly higher in TNBC tissues and cell lines, and is associated with a poor prognosis for patients. Subsequent studies revealed that inhibiting gankyrin activity triggered ferroptosis in TNBC cells. Additionally, silencing gankyrin caused an increase in the expression of the p53 protein, without altering its mRNA expression. Co-immunoprecipitation and GST pull-down experiments indicated that gankyrin and MDM2 form a complex. In mouse embryonic fibroblasts lacking both MDM2 and p53, this gankyrin/MDM2 complex was observed to ubiquitinate p53, thus raising the expression of molecules inhibited by ferroptosis, such as SLC7A11 and GPX4. Furthermore, silencing gankyrin in TNBC cells disrupted the formation of the gankyrin/MDM2 complex, hindered the degradation of p53, increased SLC7A11 expression, impeded cysteine uptake, and decreased GPX4 production. Our findings suggest that TNBC cells are able to prevent cell ferroptosis through the gankyrin/p53/SLC7A11/GPX4 signaling pathway, indicating that gankyrin may be a useful biomarker for predicting TNBC prognosis or a potential therapeutic target.

3'-epi-12β-hydroxyfroside-mediated autophagy degradation of RIPK1/RIPK3 necrosomes leads to anergy of immunogenic cell death in triple-negative breast cancer cells

Increasing studies have suggested that some cardiac glycosides, such as conventional digoxin (DIG) and digitoxin, can induce immunogenic cell death (ICD) in various tumors. We previously found that 3'-epi-12β-hydroxyfroside (HyFS), a novel cardenolide compound isolated by our group, could induce cytoprotective autophagy through inactivation of the Akt/mTOR pathway. However, whether HyFS can induce ICD remains unknown. In this study, we extend our work to further investigate whether HyFS could induce both autophagy and ICD, and we investigated the relationship between autophagy and ICD in three TNBC cell lines. Unexpectedly, compared to DIG, we found that HyFS could induce complete autophagy flux but not ICD in three human triple-negative breast cancer (TNBC) cell lines and one murine TNBC model. Inhibition of HyFS-induced autophagy resulted in the production of ICD in TNBC MDA-MB-231, MDA-MB-436, and HCC38 cells. A further mechanism study showed that formation of RIPK1/RIPK3 necrosomes was necessary for ICD induction in DIG-treated TNBC cells, while HyFS treatment led to receptor-interacting serine-threonine kinase (RIPK)1/3 necrosome degradation via an autophagy process. Additionally, inhibition of HyFS-induced autophagy by the autophagy inhibitor chloroquine resulted in the reoccurrence of ICD and reversion of the tumor microenvironment, leading to more significant antitumor effects in immunocompetent mice than in immunodeficient mice. These findings indicate that HyFS-mediated autophagic degradation of RIPK1/RIPK3 necrosomes leads to inactivation of ICD in TNBC cells. Moreover, combined treatment with HyFS and an autophagy inhibitor may enhance the antitumor activities, suggesting an alternative therapeutic for TNBC treatment.

[The effect of steatotic donor livers on the prognosis of donors and recipients after pediatric living donor liver transplantation]

Objectives: To evaluate the effects of steatotic donor livers on the safety of donors and the prognosis of donors and recipients in pediatric living donor liver transplantation. Methods: A total of 814 pediatric living donor liver transplantations were performed between January 2013 and December 2020 at Department of Pediatric Organ Transplantation,Tianjin First Central Hospital.The clinical data were collected and a retrospective study was conducted.The recipients and the donors were divided into non-steatotic donor liver group(n=733) and steatotic donor liver group(n=81) according to whether the donor graft had steatosis. The recipients and the donors in the steatotic donor liver group were further divided into mild and moderate steatosis groups based on the degree of liver steatosis.Among the donors of non-steatosis donor group,there were 307 males and 426 females,with a median age of 30 years(range:18 to 57 years);the recipients included 351 males and 382 females,with a median age of 7 months(range:4 month to 14 years).Among the donors of steatosis donor group,there were 41 males and 40 females,with a median age of 31 years(range:22 to 51 years);the recipients included 34 males and 47 females,with a median age of 8 months(range:5 months to 11 years).The donors and the recipients were followed up regularly by means of outpatient reexamination and questionnaire survey after operation.Statistical analysis of data between groups was performed using t-test,Wilcoxon rank-sum test,repeated measures ANOVA,χ² test,or Fisher's exact test,respectively.The survival curves of recipients and grafts in different groups were created by Kaplan-Meier method,and the survival rates of the steatotic donor liver group and the non-steatotic donor liver group were compared by Log-rank method. Results: There was no significant difference in the gender of donors in both groups (P=0.132).There were significant differences in the age and blood type distribution as well as body weight and body mass index(all P<0.05) between the two groups.No significant difference was seen in the recovery of liver function markers ALT and AST at 1,2,5 days and 1 month after operation (all P>0.05) between the two groups.The steatotic donor liver group showed longer operation time ((294±75) minutes vs. (264±81) minutes; t=3.149,P=0.002),increased incidence of postoperative biliary leakage (3.7%(3/81) vs. 0.5% (4/733); P=0.025) and delayed incision healing (7.4%(6/81) vs. 2.0%(15/733); P=0.013).There were no significant differences in gender,age,blood type distribution,height,weight and pediatric end-stage liver disease score of recipients between the two groups (all P>0.05).As compared to the non-steatotic donor liver group,the steatotic donor liver group showed similar levels of ALT, AST and total bilirubin within 2 weeks after operation(all P>0.05). The cumulative recipient survival rates in both groups were both 96.3%,the cumulative graft survival rates were 96.3% and 95.5%,respectively,without significant difference(both P>0.05). No statistical difference was observed in the incidence of major complications between the two groups (all P>0.05). There was no significant difference in the recovery of liver function markers of donors and recipients between mild and moderate steatosis groups(all P>0.05).The cumulative recipient survival rates were both 95.9% and the cumulative graft survival rates were both 100% in mild and moderate steatosis groups,without significant difference(P=0.592). Conclusions: The application of mild to moderate steatotic donor livers in pediatric living donor liver transplantation may prolong the operation time of donors,increase the incidence of complications such as biliary leakage and delayed incision healing. But there is no significant impact of mild to moderate steatotic donor livers on the overall postoperative recovery of donors and recipients,and the prognosis is ideal.

Immunotherapy combining tumor and endothelium cell lysis with immune enforcement by recombinant MIP-3α Newcastle disease virus in a vessel-targeting liposome enhances antitumor immunity

Background

Several agents for oncolytic immunotherapy have been approved for clinical use, but monotherapy is modest for most oncolytic agents. The combination of several therapeutic strategies through recombinant and nanotechnology to engineer multifunctional oncolytic viruses for oncolytic immunotherapy is a promising strategy.

Methods

An endothelium-targeting iRGD-liposome encapsulating a recombinant Newcastle disease virus (NDV), which expresses the dendritic cell (DC) chemokine MIP-3α (iNDV3α-LP), and three control liposomes were constructed. MIP-3α, HMGB1, IgG, and ATP were detected by western blotting or ELISA. The chemotaxis of DCs was examined by Transwell chambers. The phenotypes of the immune cells were analyzed by flow cytometry. The antitumor efficiency was investigated in B16 and 4T1 tumor-bearing mice. Immunofluorescence and immunohistochemistry were used to observe the localization of liposomes, molecular expression and angiogenesis. Synergistic index was calculated using the data of tumor volume, tumor angiogenesis and tumor-infiltrating lymphocytes.

Results

Compared with NDV-LP, treatment with iNDV3α-LP and NDV3α-LP induced stronger virus replication and cell lysis in B16 and 4T1 tumor cells and human umbilical vein endothelial cells (HUVECs) with the best response observed following iNDV3α-LP treatment. B16 and 4T1 cells treated with iNDV3α-LP produced more damage-associated molecular pattern molecules, including secreted HMGB1, ATP, and calreticulin. Moreover, iNDV3α-LP specifically bound to αvβ3-expressing 4T1 cells and HUVECs and to tumor neovasculature. Tumor growth was significantly suppressed, and survival was longer in iNDV3α-LP-treated B16-bearing and 4T1-bearing mice. A mechanism study showed that iNDV3α-LP treatment initiated the strongest tumor-specific cellular and humoral immune response. Moreover, iNDV3α-LP treatment could significantly suppress tumor angiogenesis and reverse the tumor immune suppressive microenvironment in both B16-bearing and 4T1-bearing mice.

Conclusions

In this study, iNDV3α-LP had several functions, such as tumor and vessel lysis, MIP-3α immunotherapy, and binding to αvβ3-expressing tumor and its neovasculature. iNDV3α-LP treatment significantly suppressed tumor angiogenesis and reversed the tumor immunosuppressive microenvironment. These findings offer a strong rationale for further clinical investigation into a combination strategy for oncolytic immunotherapy, such as the formulation iNDV3α-LP in this study.

[Risk factors of blood loss during liver transplantation in children with biliary atresia and its influence on prognosis]

Objectives: To study the risk factors for massive intraoperative blood loss in children with biliary atresia who underwent liver transplantation for the first time,and to analyze their impacts on graft survival,hospital stay and postoperative complications. Methods: The data of 613 children with biliary atresia who underwent liver transplantation at Department of Pediatric Organ Transplantation,Tianjin First Central Hospital from January 2015 to December 2018 were collected and analyzed. There were 270 males and 343 females, aged 7.4 (3.9) months (range: 3.2 to 148.4 months), the body weight of the recipients were (7.8±3.5) kg (range: 4.0 to 43.3 kg).According to the 85^th quad of estimated blood loss(EBL),they were divided into two groups:massive EBL group(96 cases) and non massive EBL group(517 cases). The age,height,weight and other factors between the two groups were analyzed and compared. Univariate Logistic regression and multiple stepwise regression were used to determine the risk factors of massive EBL. Then,the postoperative complications of the two groups,including portal vein thrombosis and portal vein anastomotic stenosis etc.,were analyzed and compared by chi square test. Kaplan Meier curve and log rank test were used to analyze the recipient and graft survival rate of the two groups. Results: During the study period,713 transplants were performed and 613 patients were enrolled in the study. Ninety-six patients(15.7%) had massive EBL,and the postoperative hospital stay was 21(16) days(range:2 to 116 days),the hospital stay of non-massive EBL group was 22(12)days(range:3 to 138 days)(U=24 224.0,P=0.32). Univariate Logistic regression analysis showed that the recipient's weight,Kasai portoenterostomy,platelet count,operation time and cold ischemia time were the risk factors of massive EBL during biliary atresia transplantation. Multiple regression analysis showed that cold ischemia time ≥10 hours,prolonged operation time(≥8 hours) and body weight<5.5 kg were important independent risk factors for massive EBL.The incidence of portal vein thrombosis,hepatic vein stenosis,intestinal leakage and pulmonary infection in patients with massive EBL were significantly higher than those without massive EBL(3.1% vs. 0.8%,9.4% vs. 2.1%,6.3% vs. 0.8%,30.2% vs. 20.1%,all P<0.05). The 3-year overall graft and recipient survival rate were significantly lower in patients with massive EBL than those without massive EBL(87.5% vs. 95.7%,P=0.001;84.4% vs. 95.4%,P<0.01,respectively). Conclusions: In children with biliary atresia who underwent liver transplantation for the first time,the effective control of intraoperative bleeding should shorten the operation time and reduce the cold ischemia time as far as possible,on the premise of ensuring the safety of operation. For children without growth disorder,the weight of children should be increased to more than 5.5 kg as far as possible to receive the operation. Reducing intraoperative bleeding is of great significance to the prognosis of children.

Toxicarioside O Inhibits Cell Proliferation and Epithelial-Mesenchymal Transition by Downregulation of Trop2 in Lung Cancer Cells

Toxicarioside O (TCO), a natural product derived from Antiaris toxicaria, has been identified to be a promising anticancer agent. In this study, we aimed to investigate the effect of TCO on the proliferation and epithelial-mesenchymal transition (EMT) of lung cancer cells and its molecular mechanisms. Here, we indicated that TCO inhibits the proliferation of lung cancer cells both in vitro and in vivo. Our results demonstrated that TCO induces apoptosis in lung cancer cells. Moreover, we found that TCO suppresses EMT program and inhibits cell migration in vitro. Mechanistically, TCO decreases the expression of trophoblast cell surface antigen 2 (Trop2), resulting in inhibition of the PI3K/Akt pathway and EMT program. Overexpression of Trop2 rescues TCO-induced inhibition of cell proliferation and EMT. Our findings demonstrate that TCO markedly inhibits cell proliferation and EMT in lung cancer cells and provides guidance for its drug development.

Modified unilateral video-assisted thoracoscopic extended thymectomy for myasthenia gravis using 5-mm incisions: A case report

RATIONALE

Myasthenia gravis (MG) is the most common cause of acquired neuromuscular junction disorder. Thymectomy has been established as an effective therapy for MG, as it attenuates the natural course of the disease and may result in complete remission.

PATIENT CONCERNS

We report the case of a 22-year-old female with a 6-year history of MG presented with bilateral ptosis, diplopia, and intermittent dysphagia. She denied shortness of breath, dysarthria, and fatigue.

DIAGNOSES

She had been diagnosed with MG 6 years previously at the Neurology Department of our hospital. A computed tomography (CT) scan revealed thymic hyperplasia INTERVENTIONS:: She was treated with modified unilateral VATET that minimized incision size.

OUTCOMES

Unilateral VATET was performed using two 5-mm incisions to minimize pressure on intercostal soft tissues/nerves and reduce postoperative pain.

LESSONS

The lesson learnt from this case report is that this modified VATET method could be a useful approach to the management of non-thymomatous MG. The ability to achieve complete dissection with good cosmetic results may lead to wider acceptance of this technique by patients with MG and their neurologists for earlier thymectomy and improved outcomes. Additional studies are needed to determine the superiority of this approach to established methods.

Completely thoracoscopic right upper lobectomy and mediastinal lymph node dissection

Video-assisted thoracoscopic surgery (VATS) has been constantly used in the diagnosis and treatment of intrathoracic disease. The focus of VATS is primarily concerned with the completeness of mediastinal lymph node dissection for lung cancer and the safety of surgery. Here we discuss the feasibility of VATS right upper lobectomy and systematic lymph node dissection, for a 60-year-old woman who was admitted for tumor of the right upper lobe, and describe this treatment method and the major indications. The technique of single-direction lobectomy and mediastinal lymph node dissection is a safe and feasible completely thoracoscopic lobectomy in minimally invasive approach. Single-direction lobectomy can shorten the operation time and reduce the difficulty and complexity of the procedure. The video demonstrates the manipulation of arterial and venous bleeding in thoracoscopic surgery and the skill of single-direction operation.

[Spatiotemporal variation of soil pH in Guangdong Province of China in past 30 years]

Based on the 1980s' soil inventory data and the 2002-2007 soil pH data of Guangdong Province, the spatiotemporal variation of soil pH in the Province in past 30 years was studied. In the study period, the spatial distribution pattern of soil pH in the Province had less change (mainly acidic), except that in Pearl River Delta and parts of Qingyuan and Shaoguan (weak alkaline). The overall variation of soil pH was represented as acidification, with the average pH value changed from 5.70 to 5.44. Among the soil types in the Province, alluvial soil had an increased pH, lateritic red soil, paddy soil, and red soil had a large decrement of pH value, and lime soil was most obvious in the decrease of pH value and its area percentage. The soil acidification was mainly induced by soil characteristics, some natural factors such as acid rain, and human factors such as unreasonable fertilization and urbanization. In addition, industrialization and mining increased the soil pH in some areas.

Effect of fragile histidine triad gene transduction on proliferation and apoptosis of human hepatocellular carcinoma cells

AIM: To evaluate the inhibitory effects of human fragile histidine triad (FHIT) gene on cell proliferation and apoptosis in human hepatocellular carcinoma line Hep3B in vitro.

METHODS: A recombinant pcDNA3.1 (+)/FHIT including the functional region of FHIT gene was constructed and transferred into human hepatocellular carcinoma cells in vitro. mRNA and protein expression of the FHIT gene in the transfected cells was detected by RT-PCR and Western blot, respectively. The effect of FHIT on proliferation was detected by MTT assay. Changes in cell cycle and apoptosis were assayed by flow cytometry. Five mice received subcutaneous transplantation of Hep3B-FHIT; 5 mice received subcutaneous transplantation of normal Hep3B and Hep3B-C as controls. The body weight of nude mice and tumor growth were measured.

RESULTS: RT-PCR and Western blot analysis showed that the expression level of FHIT-mRNA and FHIT protein was higher in Hep3B cells after infection with pcDNA3.1 (+)/FHIT. The growth of Hep3B cells treated with pcDNA3.1 (+)/FHIT was significantly inhibited. The pcDNA3.1 (+)/FHIT-transfected Hep3B cells showed a significantly higher cell rate at G₀-G₁ phase and increased apoptosis in comparison with controls (P < 0.05). The growth of transplanted tumor was inhibited markedly by FHIT. Tumors arising from the Hep3B-FHIT cells occurred much later than those arising from the Hep3B and Hep3B-C cells. The growth of Hep3B-FHIT cells was slow and the tumor volume was low.

CONCLUSION: Transduction of FHIT gene inhibits the growth of human hepatocellular carcinoma cells and induces cell apoptosis in vivo and in vitro.

Effects of fragile histidine triad gene transduction on growth of Hep3B human hepatocellular carcinoma cells

AIM: To evaluate the effects of the human fragile histidine triad gene on cell proliferation and apoptosis of the Hep3B human hepatocellular carcinoma line.

METHODS: A recombinant pcDNA3.1 (+)/FHIT including functional region of human fragile histidine triad gene (FHIT) was constructed for transfer into human hepatocellular carcinoma cells in vitro. mRNA and protein expressions of the gene in the transfected cells were detected by reverse transcriptase-polymerase chain reaction and Western blot, respectively. MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] assay was used to assess the effects of FHIT on proliferation. Cell cycle changes and apoptosis were measured by flow cytometry.

RESULTS: Hep3B cells expressed high levels of FHIT-mRNA and FHIT protein after infection with pcDNA3.1 (+)/FHIT. The growth of Hep3B cells treated with pcDNA3.1 (+)/FHIT was significantly inhibited. pcDNA3.1 (+)/FHIT-infected Hep3B cells showed a significant increase in G0-G1 phase and FHIT-induced apoptosis compared with controls (72.23 ± 0.84 vs 54.36 ± 0.78 and 53.17 ± 0.52, P < 0.05, respectively).

CONCLUSION: Transfer of the FHIT gene inhibited the growth of human hepatocellular carcinoma cells and induced cell apoptosis.

Dihydroayapin, a new coumarin compound from Dendrobium densiflorum

A new coumarin named dihydroayapin (1) together with seven known compounds were isolated from the stems of Dendrobium densiflorum. On the basis of physicochemical and spectral evidences, the structure of 1 was established as 6,7-methylenedioxy-3,4-dihydrobenzopyran-2-one.

Beta-adrenoceptor subtype activities of trimetoquinol derivatives: biochemical studies on human beta-adrenoceptors expressed in chinese hamster ovary cells

The beta-adrenoceptor activities of trimetoquinol (TMQ) isomers and selected derivatives were evaluated on human beta-adrenoceptor subtypes expressed in Chinese hamster ovary cells. In cAMP accumulation assays, (-)-TMQ was 214-, 281-, and 776-fold more potent than (+)-TMQ at stimulating beta(1)-, beta(2)-, and beta(3)-adrenoceptor subtypes, respectively. In radioligand binding assays, (-)-TMQ exhibited 123-, 331-, and 5-fold greater affinity than (+)-TMQ for beta(1)-, beta(2)-, and beta(3)-adrenoceptor subtypes, respectively. (-)-TMQ and (+/-)-TMQ activated the human beta(3)-adrenoceptor with an 8.2- and 3.4-fold greater efficacy, respectively, than the reference beta-adrenoceptor agonist (-)-isoproterenol (efficacy = 1). The 3',5'-diiodo analogs of TMQ were partial agonists of the beta(2)-adrenoceptor relative to (-)-isoproterenol, and their potencies were 5- to 10-fold higher at the beta(3)-adrenoceptor as compared with beta(1)-adrenoceptors. Modification of the catechol (6,7-dihydroxy) nucleus, such as replacement of the 7-hydroxy group with a chloro group (7-chloroTMQ), ring fluorination (8-fluoro and 5,8-difluoro analogs), or preparation of bioisosteric tetrahydrothiazolopyridine (THP) derivatives of TMQ yielded compounds that displayed partial agonist activity (relative to (-)-isoproterenol) or were inactive at the beta(2)-adrenoceptor and exhibited beta(3)-adrenoceptor-selective stimulation compared with the beta(1)-adrenoceptor. Furthermore, the 3',5'-diiodo-4'-methoxybenzylTHP derivative of TMQ was 65-fold more potent than the corresponding 3',4',5'-trimethoxybenzylTHP at the human beta(3)-adrenoceptor. Our results indicate that 6, 7-dihydroxy-catechol-modified and 1-benzyl halogen-substituted derivatives of TMQ represent promising leads for the development of beta(3)-adrenoceptor-selective agonists.

Murine NK cell allospecificity-1 is defined by inhibitory ligands

Hemopoietic allografts of normal and neoplastic origin are subject to NK cell-mediated resistance in mice. Susceptibility to this resistance is controlled by MHC-linked genes in a recessive manner. Several distinct specificities could be postulated to explain the strain-dependent pattern of resistance. These presumptive specificities for recognition are H-2 haplotype dependent, but the correspondence is not one-to-one. For example, resistance of H-2d or H-2b/d host to H-2 b graft operationally defines specificity-1, establishing its link with haplotype H-2b. To examine the molecular basis of specificity-1, spontaneous Dd-loss mutant clones were isolated from H-2b/d and H-2d hemopoietic cell lines, i.e., 416B of (C57BL/6 x DBA/2)F1 (B6D2F1) origin and L1210 of DBA/2 origin, both of which lack specificity-1. The expression of specificity-1 in the mutant clones was examined in vivo and in vitro. The results indicate that Dd-loss clones of 416B and L1210 lines express specificity-1. These data suggest that murine NK cell allospecificity-1 is defined primarily by the absence of the Dd molecule or other class I molecules sharing the protective motifs; no H-2b-associated genes play a relevant role. This conclusion is consistent with the missing self hypothesis of NK cell reactivity, and is in agreement with the observation that lysis of B6 targets by B6D2F1 NK cells is mediated mostly by cells that express Ly-49A and/or Ly-49G2.

Murine NK cell allospecificity-1 is defined by inhibitory ligands

Hemopoietic allografts of normal and neoplastic origin are subject to NK cell-mediated resistance in mice. Susceptibility to this resistance is controlled by MHC-linked genes in a recessive manner. Several distinct specificities could be postulated to explain the strain-dependent pattern of resistance. These presumptive specificities for recognition are H-2 haplotype dependent, but the correspondence is not one-to-one. For example, resistance of H-2d or H-2b/d host to H-2 b graft operationally defines specificity-1, establishing its link with haplotype H-2b. To examine the molecular basis of specificity-1, spontaneous Dd-loss mutant clones were isolated from H-2b/d and H-2d hemopoietic cell lines, i.e., 416B of (C57BL/6 x DBA/2)F1 (B6D2F1) origin and L1210 of DBA/2 origin, both of which lack specificity-1. The expression of specificity-1 in the mutant clones was examined in vivo and in vitro. The results indicate that Dd-loss clones of 416B and L1210 lines express specificity-1. These data suggest that murine NK cell allospecificity-1 is defined primarily by the absence of the Dd molecule or other class I molecules sharing the protective motifs; no H-2b-associated genes play a relevant role. This conclusion is consistent with the missing self hypothesis of NK cell reactivity, and is in agreement with the observation that lysis of B6 targets by B6D2F1 NK cells is mediated mostly by cells that express Ly-49A and/or Ly-49G2.

[Pulmonary encephalopathy and disturbance in amino acids metabolism]

18 kinds of serum free amino acids (SFAAs) were determined in 35 patients suffering from cor pulmonale (CP) with acute exacerbation of chronic obstructive pulmonary disease (COPD). We found that the branched-chain AAs/aromatic AAs ratio (BCAAs/AAAs) was smaller in patients with pulmonary encephalopathy (PE) than those with respiratory failure (RF) only. For the PE patients, this ratio was still smaller during unconscious period than during conscious period. Some SFAAs related to neurotransmitters were also altered during unconscious period. However, there was no significant difference between CP patients with simple RF and those without RF. When RF was controlled, the SFAAs remained unchanged. The above results suggested that disturbance in neutral AAs metabolism participates in the mechanism of PE formation.