Clinical efficacy of pemetrexed disodium in maintenance treatment of advanced lung adenocarcinoma / 中国基层医药

Objective:To investigate the clinical efficacy and adverse reactions of pemetrexed disodium in the maintenance treatment of advanced lung adenocarcinoma after chemotherapy with pemetrexed disodium and platinum.Methods:The clinical data of 35 patients with stage Ⅳ lung adenocarcinoma who received chemotherapy with pemetrexed disodium and platinum and were well treated in Beijing Huairou Hospital from January 2013 to August 2020 were retrospectively analyzed. Maintenance therapy with pemetrexed disodium was initiated after the completion of combination chemotherapy until disease progression. The clinical characteristics, therapeutic effects, adverse reactions, progression-free survival, and overall survival of the 35 patients were evaluated.Results:Among the 35 patients, no patients had complete remission, 11 patients had partial remission, 22 patients had stable disease, and 2 patients had progressive disease. The objective remission rate was 31.4%, disease control rate was 94.3%, median progression-free survival was 9.53 months, median overall survival was 18.21 months, 1-year survival rate was 68.6%, 2-year survival rate was 31.4%, and 3-year survival rate was 11.4%. Gender, age, smoking, and the baseline characteristics of patients undergoing first-line pemetrexed disodium or second-line pemetrexed disodium treatment had no effects on progression-free survival (all P > 0.05). Positive gene mutation and receiving four or more chemotherapy cycles had a protective effect on progression-free survival (both P < 0.05). Chemotherapy-related adverse reactions mainly included myelosuppression, nausea, elevated transaminase, and nephrotoxicity, all of which were mild and were relieved after symptomatic treatment. Conclusion:Pemetrexed disodium is effective and safe in the maintenance treatment of advanced lung adenocarcinoma. The results of this study are scientific.

iRECIST and atypical patterns of response to immuno-oncology drugs.

With the advent of immunotherapy as one of the keystones of the treatment of our patients with cancer, a number of atypical patterns of response to these agents has been identified. These include pseudoprogression, where the tumor initially shows objective growth before decreasing in size, and hyperprogression, hypothesized to be a drug-induced acceleration of the tumor burden. Despite it being >10 years since the first immune-oncology drug was approved, neither the biology behind these paradoxical responses has been well understood, nor their incidence, identification criteria, predictive biomarkers, or clinical impact have been fully described. Immune-based Response Evaluation Criteria in Solid Tumors (iRECIST) guidelines have been published as a revision to the RECIST V.1.1 criteria for use in trials of immunotherapeutics, and the iRECIST subcommittee (of the RECIST Working Group) is working on elucidating these aspects, with data sharing a current major challenge to move forward with this unmet need in immuno-oncology.

Comparison between the Linked Color and White Light Imaging Combined Score in the Evaluation of High-Risk Population of Gastric Cancer.

BACKGROUND: For patients undergoing gastroscopy, it is necessary to judge whether there is Helicobacter pylori infection, atrophy/intestinal metaplasia. This study aimed to evaluate and compare the light color imaging (LCI) and white light imaging (WLI) combined score during gastroscopy. METHODS: Each included patient underwent normalized gastroscopy with WLI and LCI, and all notable findings were photographed. Four endoscopists reviewed the endoscopic images of each patient. The clinical information, results of the H. pylori tests were unavailable at review. The total LCI and WLI scores of each patient were calculated and their detection in high-risk populations of gastric cancer were evaluated. The diagnostic values of LCI and WLI for intestinal metaplasia were also calculated. RESULTS: In total, 392 patients were included in the study. The degree of inflammation and proportion of active inflammation cases were significantly higher in the H. pylori gastritis group than in the non-H. pylori gastritis group; their endoscopic manifestations were also different. The LCI combined score improved the diagnostic value of each individual observation index in the diagnosis of H. pylori infection compared with the WLI combined score. The sensitivity, specificity, and accuracy were 91.9% (91.9% vs 81.5%), 91.1% (91.1% vs 80.2%), and 95.8% (95.8% vs 93.2%), respectively. The accuracy of LCI in the diagnosis of intestinal metaplasia was higher than that of WLI (83.4% vs 69.6%). CONCLUSION: The LCI and LCI combined score improved the diagnosis of H. pylori gastritis and intestinal metaplasia, and it is considered valuable in identifying the high-risk population of gastric cancer.

Clinical characteristics and gene variants of patients with infantile intrahepatic cholestasis / 中国当代儿科杂志

OBJECTIVE@#To explore the clinical characteristics and genetic findings of patients with infantile intrahepatic cholestasis.@*METHODS@#The clinical data were collected in children who were admitted to the Department of Gastroenterology in Children's Hospital, Capital Institute of Pediatrics from June 2017 to June 2019 and were suspected of inherited metabolic diseases. Next generation sequencing based on target gene panel was used for gene analysis in these children. Sanger sequencing technology was used to verify the genes of the members in this family.@*RESULTS@#Forty patients were enrolled. Pathogenic gene variants were identified in 13 patients (32%), including @*CONCLUSIONS@#The etiology of infantile intrahepatic cholestasis is complex. Next generation sequencing is helpful in the diagnosis of infantile intrahepatic cholestasis.

Risk factors of gastrointestinal hemorrhage in patients with coronary heart disease treated with dual antiplatelet therapy / 中国基层医药

Objective@#To study the risk factors of gastrointestinal hemorrhage in coronary heart disease(CHD) patients treated by dual anti-platelet therapy.@*Methods@#From January 2015 to January 2017, 200 patients with CHD in International Hospital of Peking University were studied and randomly divided into two groups according to the digital table, with 100 cases in each group.The treatment group was treated with aspirin and clopidogrel, and the control group was treated with aspirin.The patients were treated for 12 months and followed up for 6 months.The incidence rate of gastrointestinal hemorrhage was observed in the two groups, and the sex, age, renal function, HP infection, high risk of global registration of acute coronary events (GRACE) score and time of medication, combined with oral proton pump inhibitor(PPI), gastrointestinal history and other data were analyzed in the patients with gastrointestinal bleeding in the course of dual antiplatelet therapy.The risk factors of gastrointestinal hemorrhage in CHD patients treated with dual anti-platelet therapy were analyzed.@*Results@#The incidence rate of gastrointestinal bleeding of the treatment group[39.0%(39/100)] was higher than that of the control group[1.0%(1/100)](χ2=12.365, P<0.01). The age(over 70 years old)(30.0%), renal function(29.0%), Hp infection(29.0%), load dose(28.0%), combined oral PPI(26.0%) and gastrointestinal history(31.0%) in the patients with hemorrhage were significantly higher than those in the patients without bleeding(χ2=6.326, 6.326, 5.689, 6.124, 6.054, 5.365, 6.985, all P<0.05). There were no statistically significant differences in sex and GRACE score between the hemorrhage patients and patients without bleeding (all P>0.05). Multivariate logistic regression analysis showed that age, renal dysfunction and HP infection, load dose, medication time more than 3 months, combined oral administration of PPI, gastrointestinal history were the risk factors of gastrointestinal bleeding in patients with CHD combined with anti-platelet therapy(r=9.646, 7.435, 6.435, 11.769, 3.052, 4.199, 8.511, all P<0.05).@*Conclusion@#The patients with CHD are prone to gastrointestinal bleeding after dual antiplatelet therapy, and they are over 70 years old and suffer from renal insufficiency.The risk of gastrointestinal bleeding can be increased by loading dose of HP infection.

Risk factors of gastrointestinal hemorrhage in patients with coronary heart disease treated with dual anti-platelet therapy / 中国基层医药

Objective To study the risk factors of gastrointestinal hemorrhage in coronary heart disease (CHD) patients treated by dual anti-platelet therapy.Methods From January 2015 to January 2017,200 patients with CHD in International Hospital of Peking University were studied and randomly divided into two groups according to the digital table,with 100 cases in each group.The treatment group was treated with aspirin and clopidogrel,and the control group was treated with aspirin.The patients were treated for 12 months and followed up for 6 months.The incidence rate of gastrointestinal hemorrhage was observed in the two groups,and the sex,age,renal function,HP infection,high risk of global registration of acute coronary events (GRACE) score and time of medication,combined with oral proton pump inhibitor(PPI),gastrointestinal history and other data were analyzed in the patients with gastrointestinal bleeding in the course of dual antiplatelet therapy.The risk factors of gastrointestinal hemorrhage in CHD patients treated with dual anti-platelet therapy were analyzed.Results The incidence rate of gastrointestinal bleeding of the treatment group[39.0％ (39/100)] was higher than that of the control group[1.0％ (1/100)] (x2 =12.365,P ＜ 0.01).The age(over 70 years old) (30.0％),renal function (29.0％),Hp infection (29.0％),load dose (28.0％),combined oral PPI(26.0％) and gastrointestinal history(31.0％) in the patients with hemorrhage were significantly higher than those in the patients without bleeding(x2 =6.326,6.326,5.689,6.124,6.054,5.365,6.985,all P ＜0.05).There were no statistically significant differences in sex and GRACE score between the hemorrhage patients and patients without bleeding (all P ＞0.05).Multivariate logistic regression analysis showed that age,renal dysfunction and HP infection,load dose,medication time more than 3 months,combined oral administration of PPI,gastrointestinal history were the risk factors of gastrointestinal bleeding in patients with CHD combined with anti-platelet therapy (r=9.646,7.435,6.435,11.769,3.052,4.199,8.511,all P＜0.05).Conclusion The patients with CHD are prone to gastrointestinal bleeding after dual antiplatelet therapy,and they are over 70 years old and suffer from renal insufficiency.The risk of gastrointestinal bleeding can be increased by loading dose of HP infection.

Efficacy observation of pemetrexed treatment in advanced non -squamous non -small cell lung cancer who failed first line therapy / 中国基层医药

Objective To observe the clinical effects of pemetrexed alone or pemetrexed combined with platinum in the treatment of advanced non -squamous non -small cell lung cancer who failed first line therapy. Methods 34 patients with advanced NSCLC who had failed to previous chemotherapy and all of these patients had been confirmed with pathology or cytology.Pemetrexed monotherapy group included 14 cases and pemetrexed plus platinum group included 20 cases.21 days as one cycle.All patients who received 2 or more cycles could be evaluated. Results No complete response (CR)occurred.There were 3 cases of partial response (PR),15 cases of stable disease(SD)and 16 cases of progressive disease(PD)in the 34 patients.The disease control rate was 52.9%(18 /34).The median progressive free survival was 2.7 months.The major toxic reaction included leucopenia,anemia and gastrointestinal response.Conclusion Pemetrexed or pemetrexed combined with platinum can prolong the survival time of some patients of non -squamous non -small cell lung cancer who failed first line therapy.The toxic effects can be tolerated.

Comparison of the effect of FOLFOX4 regimen and XELOX regimen in the treatment of patients with ad-vanced colorectal cancer / 中国基层医药

Objective To observe the efficacy and untoward reactions of FOLFOX4 regimen and XELOX regimen in the treatment of patients with advanced colorectal cancer.Methods Fifty four advanced colorectal cancer patients were randomly divided into two groups.Group A (FOLFOX4):28 patients were treated with oxaliplatin 85 mg/m2 on day 1,LV 200 mg/m2 as a 2h infusion followed by bolus 5 -FU 400 mg/m2 and a 24h infusion of 5 -Fu 600 mg/m2 ,repeated for consecutive days every 2 weeks.One cycle was 14 days and efficacy was evaluated after 4 cycles.Group B(XELOX):26 patients were treated with oxaliplation 130mg/m2 on day 1,capecitabine 1 000 mg/m2 orally daily for 14 days.One cycle was 21 or 28 days and efficacy was evaluated after 2 cycles.Efficacy of the two groups was evaluated at 2 cycles.Results All 54 patients were available for evaluating objective response.In A group,the overall response rate was 46.4%,and the overall response rate was 42.3% in B group.The overall response rate of A group was slightly higher than B group,but there was no statistically significant difference(χ2 =0.093,P =0.791 ).Adverse reactions:thrombocytopenia incidence rate and the peripheral nerve toxicity had no significant differences between the two groups(χ2 =0.552,0.108,P =0.550,0.787).The incidence rates of nausea, vomit,diarrhea and leucocytopenia in B group were lower than those in A group(χ2 =9.495,4.862,6.273,P =0.003,0.033,0.108).The incidence rate of hand -foot syndrome was higher in B group than in A group(χ2 =13.389,P =0.000),but the severity was less(grade Ⅰ ~Ⅱ).Conclusion The response rate in the treatment of advanced colorectal cancer was similar between XELOX and FOLFOX4 regiments,but XELOX regiment has the advantages of more convenience,better safety.Thus,XELOX regiment is worth recommending as a first -line therapy for the treatment of patients with advanced colorectal cancer.

Genetic polymorphism analysis of killer cell immunoglobulin-like receptor genes in the Chinese Uygur population.

Human killer cell immunoglobulin-like receptors are expressed in natural killer cells and subsets of T lymphocytes. They regulate these cells upon interaction with human leukocyte antigen class I molecules and other ligands presented by target cells. KIR gene frequencies and haplotype distributions have been shown to differ significantly between populations from different geographical regions and ethnic origins, which relates to functional variations in the immune response. We have investigated KIR gene frequencies and genotype diversities of 15 KIR genes (KIR2DL1, 2DL2, 2DL3, 2DL4, 2DL5, 2DS1, 2DS2, 2DS3, 2DS4, ID, 2DS5, 3DL1, 3DL2, 3DL3, 3DS1) and two pseudogenes (KIR3DP1 and 2DP1) in 120 unrelated healthy individuals of the Uygur population living in the Xinjiang autonomous region of China. All individuals were typed positive for the four framework loci KIR3DL3, 2DL4, 3DL2 and KIR3DP1, while activating genes (KIR2DS1, 2DS2, 2DS3, 2DS5 and KIR3DS1) indicated some variation in this population. KIR3DS1 was found in a higher frequency in the studied population than in other groups from China. Linkage disequilibrium among KIR genes displayed a wide range. χ(2) analysis, conducted among non-ubiquitous genes, based on the KIR gene frequency data from our study population and previously published population data, revealed significant differences in the KIR2DL1, 2DL2, 2DL3, 2DL5, 3DL1, 2DS1, 2DS2, 2DS3, 2DS5, and 3DS1 genes. A neighbor-joining phylogenic tree, built using the observed carrier frequencies data of 13 KIR loci (KIR2DL1, 2DL2, 2DL3, 2DL4, 2DL5, 3DL1, 3DL2, 3DL3, 2DS1, 2DS2, 2DS3, 2DS5, and 3DS1), showed relationships between the population studied and other previously reported populations. The present study can therefore be valuable for enriching the ethnical gene information resources of the KIR gene pool, for population origin studies and for KIR-related clinical practice.

1-(4-Benz-yloxy-2-hy-droxy-phen-yl)ethanone.

The title compound, C(15)H(14)O(3), has been obtained from the reaction of 2,4-dihy-droxy-acetophenone, potassium carbonate and benzyl bromide. The remaining hy-droxy group is involved in an intra-molecular O-H⋯O hydrogen bond. In the crystal, inter-molecular C-H⋯O contacts occur.

[The relationship between GAPDH mRNA degradation in the mouse liver and postmortem interval].

OBJECTIVE: To explore the relationship between degradation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA in the mouse liver and postmortem interval (PMI). METHODS: Sixty NIH mice were sacrificed by cervical dislocation and suffocation, and then placed into 10 degrees C and 25 degrees C temperature-controlling systems. The changes of GAPDH mRNA in the liver were detected by two-step fluorimetric reverse transcriptase polymerase chain reaction (RT-PCR) technique and nucleic acids protein cryoscope from 0 to 48 h postmortem. RESULTS: In the mouse liver, the amplification products of GAPDH mRNA could be examined within 48 h postmortem in 10 degrees C temperature-controlling system and within 36 h postmortem in 25 degrees C temperature-controlling system. The amplification products showed a decreasing tendency. CONCLUSION: Degradation of GAPDH mRNA in the mouse liver is negative correlation with PMI. GAPDH mRNA could be a new marker for estimation of PMI.

The relationship between GAPDH mRNA degradation in the mouse liver and postmortem interval / 法医学杂志

OBJECTIVE@#To explore the relationship between degradation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA in the mouse liver and postmortem interval (PMI).@*METHODS@#Sixty NIH mice were sacrificed by cervical dislocation and suffocation, and then placed into 10 degrees C and 25 degrees C temperature-controlling systems. The changes of GAPDH mRNA in the liver were detected by two-step fluorimetric reverse transcriptase polymerase chain reaction (RT-PCR) technique and nucleic acids protein cryoscope from 0 to 48 h postmortem.@*RESULTS@#In the mouse liver, the amplification products of GAPDH mRNA could be examined within 48 h postmortem in 10 degrees C temperature-controlling system and within 36 h postmortem in 25 degrees C temperature-controlling system. The amplification products showed a decreasing tendency.@*CONCLUSION@#Degradation of GAPDH mRNA in the mouse liver is negative correlation with PMI. GAPDH mRNA could be a new marker for estimation of PMI.

Study on relationship between chemical castration and thymic function following hematopoietic stem cell transplantation / 中华血液学杂志

<p><b>OBJECTIVE</b>To evaluate the impact of luteinizing hormone-releasing hormone (LHRH) on the protection of thymic function after allogenic hematopoietic stem cell transplantation (allo-HSCT).</p><p><b>METHODS</b>Murine model of MHC mismatched allogeneic HSCT (C57BL/6-->BALB/c) was established. The severity of acute graft-versus-host-disease (GVHD) was assessed according to a clinical scoring system. The intra-cellular levels of IFN gamma, TNFalpha and IL-1 beta in thymocyte were analyzed by protein array and thymic function by quantification of signal-joint TCR rearrangement excision circles (sjTRECs).</p><p><b>RESULTS</b>All recipients in group A (allogeneic mice), B (allogeneic LHRH castrated-mice) and C (syngenic mice) achieved hematopoietic reconstitution. White blood cell (WBC) over 1.0 x 10(9)/L in groups A, B and C were on day (11.2 +/- 1.4), day (9.8 +/- 0.6) and day (9.7 +/- 0.7), respectively (P = 0.003, 0.002). The onset of acute GVHD in group B was (14.1 +/- 0.7) d and in group A was (11.4 +/- 1.2) d (P = 0.000). All mice in groups A and B developed acute GVHD. No mice occurred aGVHD in group C. The average scores of acute GVHD in groups A and B were (9.1 +/- 0.7) and (5.1 +/- 1.0), respectively (P = 0.000). The levels of IFN gamma, TNFalpha and IL-1 beta in control group were (2.3 +/- 2.5) ng/ml, (1.7 +/- 1.1) pg/ml and (1.8 +/- 1.2) pg/ml, respectively. The IFN gamma levels in groups A, B and C were (10.5 +/- 2.1) ng/ml, (6.7 +/- 2.1) ng/ml and (5.2 +/- 3.3) ng/ml, TNFalpha levels were (7.0 +/- 2.6) pg/ml, (4.3 +/- 0.8) pg/ml and (3.0 +/- 1.8) pg/ml, and IL-1 beta levels were (24.9 +/- 9.0) pg/ml, (17.4 +/- 3.9) pg/ml and (10.8 +/- 3.1) pg/ml, respectively. There were significant differences in the levels of cytokines between group A and the control group (P = 0.000, 0.000, 0.000). The levels of cytokines in group B were significantly higher than those in control group (P = 0.000, 0.003, 0.000). The levels of IFN gamma and IL-beta in group C were significantly higher than those of in control group (P = 0.015, 0.013), and so did in group A than in group B (P = 0.002, 0.002, 0.004), and in group A than in group C (P = 0.000, 0.000, 0.000). The analysis of linear regression showed that the average levels of IFN gamma and TNFalpha paralleled with aGVHD scores (r(2) = 0.359, P = 0.045; r(2) = 0.228, P = 0.019). The average sjTRECs copies/1000 PBMNCs were (39.4 +/- 44.7) in the control group and (12.3 +/- 13.0), (58.0 +/- 71.8) and (19.6 +/- 14.6) in groups A, B and C, respectively. There was no significant difference in the multiple comparisons of peripheral blood levels of sjTRECs among these four groups (P = 0.468).</p><p><b>CONCLUSION</b>IFN gamma, TNFalpha and IL-1 beta might be involved in the damage to the thymus by acute GVHD. Sex steroid inhibitor can not only reduce the severity of thymic damage after allo-HSCT, but also reduce the severity of aGVHD and the mechanism might be associated with the reduction of intra-cellular levels of IFN gamma in thymocyte.</p>

Expression of monocyte chemoattractant protein-1 in sudden death due to viral myocarditis and its medicolegal significance / 法医学杂志

OBJECTIVE@#To explore the expression and significance of monocyte chemoattractant protein-1 (MCP-1) in myocardium in sudden death caused by viral myocarditis (VMC).@*METHODS@#To investigate the expression of MCP-1 in VMC sudden death group and control group using improved immunohistochemical technique and to compare the difference of the expression of MCP-1 between two groups with statistical method.@*RESULTS@#In VMC sudden death group, MCP-1 was positively expressed in 17 of 20 cases. While only 4 of the 20 cases in the control group showed a mildly positive expression sparsely in myocardium, and the rest cases were completely negative. The rate of positive expression of MCP-1 in VMC group was obviously higher than that of the control group (P<0.01).@*CONCLUSION@#The expression of MCP-1 detected by immunohistochemistry provides an objective morphologic evidence for the diagnosis of VMC sudden death in forensic pathology.

A clinical analysis of severe cyclosporine A-related neurotoxicity after allogenic hematopoietic stem cell transplantation / 中华内科杂志

Objective To investigate the morbidity,clinical manifestations,and imageology characteristics,and the influencing factors of severe cyclosporine A(CsA)-related neurotoxicity(SNCT)in the patients after allogenic hematopoietic stem cell transplantation(allo-HSCT).Methods Finding of SNCT was carried out in 164 allo-HSCT recipients from January 2003 to June 2006.Clinical characteristics were analysed,including precursory symptoms and clinical manifestations.Associations between the onset of SNCT with blood CsA levels,age,transplant types,human leucocyte antigen(HIJA)matching,conditioning regimens,antihuman thymocyte globulin(ATG)used in the prevention and treatment for graft-versus-host disease(GVHD)and intravenous corticosteroid used for acute GVHD were analyzed.Statistical analysis was performed with Binary Logistic Regression using SPSS/PC version 11.0.Results Thirteen patients(7.93%)were identified to have SNCT,including seizures(n=8,4.88%),paralysis(n=6,3.66%),coma(n:2,1.22%),cerebllar ataxia(n=3,1.83%)and chondrioid encephalomyopathy (n=1,0.61%).All the patients had precursory symptoms prior SNCT including headache(n=8),agitation(n=4)and hypertension(n=6).Magnetic resonance imaging(MRI)performed in twelve patients after SNCT showed that eleven patients had signal abnormalities in cerebral cortex and cerebral white matter.Six patients examined with computerized tomography(CT)had no abnormal findings.After extenuation or withdrawal of CsA.ten patients had complete recovery.two had partial recovery and one died of SNCT.Simple effect analysis of Binary Logistic Regression showed that the associations between the onset of SNCT with blood CsA levels.transplanta types.HLA matching.ATG used in the prevention and treatment for GVHD and intravenous corticosteroid used for acute GVHD were of statistical significance.The multiple effect analysis of Binary Logistic Regression showed that the associations of the onset of SNCT with blood CsA levels and ATG used had statistical significance and the odds ratio(OR)was 1.007(P=0.006) and 6.727(P=0.030),respectively.Conclusions 91.67%of the allo-HSCT recipients with SNCT have MRI abnormalities.High blood CsA levels and the use of ATG Call elevate the risk of the occurrence of SNCT.

Control of hydrogen bond strengths through push-pull effects triggered by a remote reaction center: a theoretical study.

In an effort to manipulate the bond strengths of hydrogen bonds, we have studied a three-component chemical system consisting of a reaction center, a conjugated bridge, and a hydrogen-bonding site. Protonation of the reaction center triggers intramolecular charge transfer from the hydrogen-bonding site, altering its affinity to bind to an acceptor. Previously, we had found that this communication (signal transduction) between the reaction center and the hydrogen-bonding site does not necessarily die out with increasing length of the conjugated bridge. In certain cases, this signal transduction is maintained-and even amplified-over long distances (I. Chao, T.-S. Hwang, Angew. Chem. 2001, 113, 2775-2777; Angew. Chem. Int. Ed. 2001, 40, 2703-2705). In this study we report the results of an extensive theoretical investigation of this problem to provide insights into this intriguing phenomenon. In the systems we investigated it was found that the push-pull process between the hydrogen-bonding site and the protonatable reaction center was mediated with the greatest facility by conjugated bridges with low-lying pi and pi* orbitals.