Objective:To evaluate the expression of tertiary lymphoid structures (TLS) in renal tissues, and the relationship between TLS and clinicopathological changes and prognosis in idiopathic membranous nephropathy (IMN) patients.Methods:It was a single center retrospective study. The patients with IMN diagnosed by renal biopsy at Shengjing Hospital Affiliated to China Medical University from January 2018 to December 2020 were enrolled, and their clinicopathological data were collected. Immunohistochemistry was used to evaluate the expression of TLS in renal tissues. According to whether TLS expression in renal tissues was positive or not, the patients were divided into TLS-positive group and TLS-negative group, and the baseline differences in clinicopathological data between the two groups were compared. The clinical remission included complete remission and partial remission. Logistic regression analysis was used to analyze the correlation between serum phospholipase A2 receptor (PLA2R) antibody titer and positive TLS expression in renal tissues. Kaplan-Meier survival curve and log-rank test were performed to analyze the differences of proteinuria remission rates between TLS-positive and TLS-negative groups. Cox regression analysis was employed to identify the related factors of proteinuria remission. The receiver operating characteristic (ROC) curve was used to evaluate the value of TLS in predicting proteinuria remission.Results:A total of 120 IMN patients were included in this study, with age of 50.00 (40.00, 57.75) years and 78 (65.00%) males. The 24-hour urinary protein was (7.54±4.14) g, 89 (74.17%) patients were positive for serum PLA2R antibody, and the serum PLA2R antibody titer was 90.49 (48.88, 155.33) RU/ml. Immunohistochemical results showed that TLS was mainly distributed in the renal cortex glomeruli or around renal blood vessels in renal tissues. There were 43 patients in the TLS-positive group and 77 patients in the TLS-negative group. The positive rate of serum PLA2R antibody in the TLS-positive group was 83.72% (36/43). Compared with the TLS-negative group, the TLS-positive group had lower serum albumin ( t=-3.474, P<0.001) and estimated glomerular filtration rate ( Z=-2.076, P=0.045), while serum creatinine ( t=2.006, P=0.028), 24-hour urinary protein ( t=4.140, P<0.001), serum PLA2R antibody titer ( Z=4.628, P=0.001), glomerulosclerosis degree ( Z=2.403, P=0.019), and proportions of hypertension ( χ2=6.511, P=0.011), renal interstitial fibrosis ( χ2=4.088, P=0.043), renal interstitial inflammatory cell infiltration ( χ2=9.261, P=0.002), tubular atrophy ( χ2=4.936, P=0.026) and extremely high-risk of kidney disease progression ( χ2=9.352, P=0.002) were higher. Multivariate logistic regression analysis showed that serum PLA2R antibody titer was an independent factor correlated with positive TLS expression in renal tissues ( OR=1.014, 95% CI 1.007-1.021). The median follow-up time was 18.00 (95% CI 16.07-19.93) months. Kaplan-Meier survival curve showed that the proteinuria remission rate in the TLS-positive group was lower than that in the TLS-negative group (Log-rank χ2=9.339, P=0.002). Cox regression analysis showed that positive TLS expression was an independent factor correlated with proteinuria remission ( HR=0.228, 95% CI 0.177-0.297). ROC curve showed that TLS had a certain clinical predictive value for proteinuria remission ( AUC=0.703, 95% CI 0.608-0.798). Conclusions:IMN patients with positive TLS expression in renal tissues have a lower proteinuria remission rate, more severe pathological damage, and a higher risk of disease progression. TLS is expected to become a pathological marker for predicting the severity and prognosis of IMN.

Objective To investigate programmed death including necroptosis,apoptosis,autophagy,ferroptosis,and pyroptosis in bone marrow megakaryocytes of mice during sepsis and its impact on platelet production capacity and coagulation function in mice.Methods C57BL/6J mice were randomly divided into a sham operation group(sham group)and a sepsis model group(CLP group).Peripheral blood platelets and coagulation function were measured by abdominal aortic blood sampling at 24 h postoperatively in both sham and CLP groups.After the mice were sacrificed,long bones of both lower limbs were taken,and bone marrow megakaryocytes were extracted using megakaryocyte separation solution and immunomagnetic bead separation.Laser confocal microscopy was used to observe the activation of programmed death-related marker molecules in mouse bone marrow megakaryocytes.Flow cytometry was used to detect programmed death rate,platelet production phenotype,and platelet surface markers(CD41,CD42b,CD61)of megakaryocytes.Western blotting was used to detect the expression of programmed death-related proteins in megakaryocytes.Results Compared with the sham group,the CLP group showed significant decreases in the number of platelets during acute sepsis(24 h)(P<0.000 1),significant increases in platelet distri-bution width(PDW)and mean platelet volume(MPV)(P<0.01),significant prolonging of thrombin time(TT),prothrombin time(PT),and activated partial thromboplastin time(APTT)(P<0.000 1,P<0.001,P<0.01),and significant reduction in fibrinogen(Fib)(P<0.000 1).Compared with the Con/sham group,the LPS/CLP group exhibited significant increases in the platelet production phenotype of megakaryocyte,the number of PLP in the supernatant,and the expression levels of platelet surface markers(CD41,CD42b,CD61).The rates of megakaryocyte necroptosis/apoptosis,pyroptosis,and ferroptosis were significantly elevated at 24 h post-CLP surgery.Laser confo-cal microscopy showed significant activation of LC3,P-MLKL,Caspase-1,and Fe2+in megakaryocytes of mice after CLP surgery.Western blotting results revealed that the CLP group exhibited a significant increase in the activa-tion rate of necroptosis-related protein P-MLKL(P<0.001),a significant increase in the cleavage of pyroptosis-related proteins GSDMD and GSDMD-N(P<0.01,P<0.001,respectively),a significant increase in the expres-sion of ferroptosis-related protein ACSL4(P<0.01),and a significant decrease in the expression of GPX4(P<0.01)compared to the sham group.Additionally,the CLP group demonstrated significant increases in the expression of apoptosis-related protein Bax,the cleavage of autophagy-related protein LC3B-Ⅱ,and the expression of P62(P<0.05,P<0.001,P<0.001,respectively).Inhibition of apoptosis with programmed cell death inhibitors decreased platelet production function of megakaryocyte,while inhibition of necroptosis and pyroptosis had limited effects on platelet production function of megakaryocyte.Inhibition of ferroptosis and autophagy enhanced platelet production function of megakaryocyte.Conclusion Significant programmed death of megakaryocytes was observed during the acute phase of sepsis(24 h).Among those megakaryocytes,apoptosis is an important mechanism for the differentia-tion of platelet production phenotype and increased platelet production capacity of megakaryocyte.Overactive autophagy and ferroptosis in megakaryocytes lead to megakaryocyte dysfunction,which is an important mechanism for coagulation abnormalities in sepsis.

Objective To investigate programmed death including necroptosis,apoptosis,autophagy,ferroptosis,and pyroptosis in bone marrow megakaryocytes of mice during sepsis and its impact on platelet production capacity and coagulation function in mice.Methods C57BL/6J mice were randomly divided into a sham operation group(sham group)and a sepsis model group(CLP group).Peripheral blood platelets and coagulation function were measured by abdominal aortic blood sampling at 24 h postoperatively in both sham and CLP groups.After the mice were sacrificed,long bones of both lower limbs were taken,and bone marrow megakaryocytes were extracted using megakaryocyte separation solution and immunomagnetic bead separation.Laser confocal microscopy was used to observe the activation of programmed death-related marker molecules in mouse bone marrow megakaryocytes.Flow cytometry was used to detect programmed death rate,platelet production phenotype,and platelet surface markers(CD41,CD42b,CD61)of megakaryocytes.Western blotting was used to detect the expression of programmed death-related proteins in megakaryocytes.Results Compared with the sham group,the CLP group showed significant decreases in the number of platelets during acute sepsis(24 h)(P<0.000 1),significant increases in platelet distri-bution width(PDW)and mean platelet volume(MPV)(P<0.01),significant prolonging of thrombin time(TT),prothrombin time(PT),and activated partial thromboplastin time(APTT)(P<0.000 1,P<0.001,P<0.01),and significant reduction in fibrinogen(Fib)(P<0.000 1).Compared with the Con/sham group,the LPS/CLP group exhibited significant increases in the platelet production phenotype of megakaryocyte,the number of PLP in the supernatant,and the expression levels of platelet surface markers(CD41,CD42b,CD61).The rates of megakaryocyte necroptosis/apoptosis,pyroptosis,and ferroptosis were significantly elevated at 24 h post-CLP surgery.Laser confo-cal microscopy showed significant activation of LC3,P-MLKL,Caspase-1,and Fe2+in megakaryocytes of mice after CLP surgery.Western blotting results revealed that the CLP group exhibited a significant increase in the activa-tion rate of necroptosis-related protein P-MLKL(P<0.001),a significant increase in the cleavage of pyroptosis-related proteins GSDMD and GSDMD-N(P<0.01,P<0.001,respectively),a significant increase in the expres-sion of ferroptosis-related protein ACSL4(P<0.01),and a significant decrease in the expression of GPX4(P<0.01)compared to the sham group.Additionally,the CLP group demonstrated significant increases in the expression of apoptosis-related protein Bax,the cleavage of autophagy-related protein LC3B-Ⅱ,and the expression of P62(P<0.05,P<0.001,P<0.001,respectively).Inhibition of apoptosis with programmed cell death inhibitors decreased platelet production function of megakaryocyte,while inhibition of necroptosis and pyroptosis had limited effects on platelet production function of megakaryocyte.Inhibition of ferroptosis and autophagy enhanced platelet production function of megakaryocyte.Conclusion Significant programmed death of megakaryocytes was observed during the acute phase of sepsis(24 h).Among those megakaryocytes,apoptosis is an important mechanism for the differentia-tion of platelet production phenotype and increased platelet production capacity of megakaryocyte.Overactive autophagy and ferroptosis in megakaryocytes lead to megakaryocyte dysfunction,which is an important mechanism for coagulation abnormalities in sepsis.

Objective:To evaluate the expression of tertiary lymphoid structures (TLS) in renal tissues, and the relationship between TLS and clinicopathological changes and prognosis in idiopathic membranous nephropathy (IMN) patients.Methods:It was a single center retrospective study. The patients with IMN diagnosed by renal biopsy at Shengjing Hospital Affiliated to China Medical University from January 2018 to December 2020 were enrolled, and their clinicopathological data were collected. Immunohistochemistry was used to evaluate the expression of TLS in renal tissues. According to whether TLS expression in renal tissues was positive or not, the patients were divided into TLS-positive group and TLS-negative group, and the baseline differences in clinicopathological data between the two groups were compared. The clinical remission included complete remission and partial remission. Logistic regression analysis was used to analyze the correlation between serum phospholipase A2 receptor (PLA2R) antibody titer and positive TLS expression in renal tissues. Kaplan-Meier survival curve and log-rank test were performed to analyze the differences of proteinuria remission rates between TLS-positive and TLS-negative groups. Cox regression analysis was employed to identify the related factors of proteinuria remission. The receiver operating characteristic (ROC) curve was used to evaluate the value of TLS in predicting proteinuria remission.Results:A total of 120 IMN patients were included in this study, with age of 50.00 (40.00, 57.75) years and 78 (65.00%) males. The 24-hour urinary protein was (7.54±4.14) g, 89 (74.17%) patients were positive for serum PLA2R antibody, and the serum PLA2R antibody titer was 90.49 (48.88, 155.33) RU/ml. Immunohistochemical results showed that TLS was mainly distributed in the renal cortex glomeruli or around renal blood vessels in renal tissues. There were 43 patients in the TLS-positive group and 77 patients in the TLS-negative group. The positive rate of serum PLA2R antibody in the TLS-positive group was 83.72% (36/43). Compared with the TLS-negative group, the TLS-positive group had lower serum albumin ( t=-3.474, P<0.001) and estimated glomerular filtration rate ( Z=-2.076, P=0.045), while serum creatinine ( t=2.006, P=0.028), 24-hour urinary protein ( t=4.140, P<0.001), serum PLA2R antibody titer ( Z=4.628, P=0.001), glomerulosclerosis degree ( Z=2.403, P=0.019), and proportions of hypertension ( χ2=6.511, P=0.011), renal interstitial fibrosis ( χ2=4.088, P=0.043), renal interstitial inflammatory cell infiltration ( χ2=9.261, P=0.002), tubular atrophy ( χ2=4.936, P=0.026) and extremely high-risk of kidney disease progression ( χ2=9.352, P=0.002) were higher. Multivariate logistic regression analysis showed that serum PLA2R antibody titer was an independent factor correlated with positive TLS expression in renal tissues ( OR=1.014, 95% CI 1.007-1.021). The median follow-up time was 18.00 (95% CI 16.07-19.93) months. Kaplan-Meier survival curve showed that the proteinuria remission rate in the TLS-positive group was lower than that in the TLS-negative group (Log-rank χ2=9.339, P=0.002). Cox regression analysis showed that positive TLS expression was an independent factor correlated with proteinuria remission ( HR=0.228, 95% CI 0.177-0.297). ROC curve showed that TLS had a certain clinical predictive value for proteinuria remission ( AUC=0.703, 95% CI 0.608-0.798). Conclusions:IMN patients with positive TLS expression in renal tissues have a lower proteinuria remission rate, more severe pathological damage, and a higher risk of disease progression. TLS is expected to become a pathological marker for predicting the severity and prognosis of IMN.

OBJECTIVE To study the improvement effects of poria acid on insulin resistance in rats with polycystic ovary syndrome （PCOS） and its mechanism. METHODS One hundred and twenty-six female rats were randomly separated into blank group， PCOS group， poria acid low-dose group （8.33 mg/kg）， pachymic acid high-dose group （33.32 mg/kg）， ethinylestradiol cyproterone group （positive control group， 0.34 mg/kg）， recombinant rat high mobility group protein B1 protein （rHMGB1） group （8 μg/kg）， and poria acid high dose+rHMGB1 group （33.32 mg/kg poria acid+8 μg/kg rHMGB1）， with 18 rats in each group. Except for the blank group， the rats in all other groups were given Letrozole suspension intragastrically to construct the PCOS model. After successful modeling， administration was performed once a day for 4 weeks. After medication， the fasting blood glucose and fasting insulin levels， and insulin resistance index （HOMA-IR） were measured in rats； the levels of follicle-stimulating hormone （FSH）， luteinizing hormone （LH） and testosterone （T） in rat serum， and the levels of interleukin-1β （IL-1β） and tumor necrosis factor- α （TNF- α） in ovarian tissue were detected； ovarian coefficients of rats were calculated； the pathological changes of ovarian tissue were observed； the expressions of HMGB1， receptor for advanced glycosylation elaine_ tanghong@sina.com end product （RAGE） and phosphorylated nuclear factor κB p65 （p-NF-κB p65） proteins were determined in ovarian tissue of rats. RESULTS Compared with the blank group， the pathological injury of ovarian tissue of rats in the PCOS group was serious， the levels of fasting blood glucose and fasting insulin， HOMA-IR and ovarian coefficient were increased， the levels of serum LH and T were increased， while the levels of FSH were decreased； the levels of IL-1β and TNF-α， the expressions of HMGB1， RAGE and p-NF-κB p65 protein in ovarian tissue were increased， with statistical significance （P＜0.05）. Compared with the PCOS group， pathological damage of ovarian tissue was reduced in poria acid low-dose and high-dose groups and ethinylestradiol cyproterone group， and fasting blood glucose， fasting insulin levels， HOMA-IR and ovarian coefficient were decreased； serum LH and T levels were decreased， while FSH levels were increased； the levels of IL-1β and TNF-α and the expressions of HMGB1， RAGE and p-NF-κB p65 protein in ovarian tissue were decreased， with statistical significance （P＜0.05）. The trend of corresponding indexes in rHMGB1 group was opposite to the above （P＜0.05）. Compared with poria acid high-dose group， the changes of the above indexes were reversed significantly in poria acid high-dose+rHMGB1 group （P＜0.05）. CONCLUSIONS Poria acid may improve insulin resistance and inhibit inflammatory reaction in PCOS rats by inhibiting HMGB1/ RAGE pathway.

Objective To explore the role and underlying mechanism of type Ⅲ secretion system(T3SS)in regulating the internalization of Pseudomonas aeruginosa(PA)into pulmonary epithelial cells.Methods The human non-small cell lung cancer A549 cells were infected with or without PA strains,including wild-type PAO1(a standard experimental PA strain),△exsA(knockout of the critical activator for T3SS genes),△pscJ(T3SS secretion-defective strain)and PAO1-E(EGTA-induced high expression of T3SS genes).The A549 cells pretreated with ERK inhibitor U0126 or reactive oxygen species(ROS)inhibitor apocynin(APO)/N-acetyl-L-cysteine(NAC)were infected with PAO1 or PAO1-E strain.Thus,the experiment was grouped as follows:the mock-treated group,PAO1-or PAO1-E-infected group,inhibitor-treated group,and PAO1/PAO1-E plus inhibitor-treated group.Extracellular bacteria were killed by gentamicin,and the cell lysates were diluted and then plated on PA screening plates.Bacterial amounts were detected by counting colony-forming units(CFUs).The production of ROS was analyzed using fluorescent probe labeling and flow cytometry.The activation of the ERK pathway was detected by Western blotting.Results Compared with the PAO1-infected group,the intracellular bacteria and ROS level in △exsA-or△pscJ-infected cells were lower(P＜0.05,P＜0.01),so was the generation of ROS(P＜0.01);In contrast,those of the PAO1-E strain-infected cells displayed an opposite trend(P＜0.01).Compared with the PAO1-or PAO1-E-infected group,the cells pretreated with APO/NAC followed by PAO1 or PAO1-E infection showed reduced intracellular bacterial amounts(P＜0.01).Compared to the PAO1-infected A549 cells,the phosphorylation level of ERK was increased in the △exsA-or △pscJ-infected cells(P＜0.01),while that level was suppressed in the PAO1-E-treated cells(P＜0.01).Compared with the PAO1-infected group,the PAO1-infected cells pretreated with U0126 displayed reduced ERK activation,elevated ROS production,and increased intracellular counts of PAO1(P＜0.01).Conclusion T3SS-mediated inhibition of the ERK pathway promotes the production of ROS and the internalization of PA in lung epithelial cells.

Objective:To investigate the feasibility and value of participatory bilingual teaching in nuclear medicine teaching.Methods:With the same chapter of Nuclear Medicine as the teaching contents, the traditional method of cramming bilingual teaching was used for the clinical medical students in the class of 2014 of the seven-year program and the five-year program, and the method of participatory bilingual teaching was used for the students in the class of 2015. The methods of periodical achievement test, questionnaire survey, and final examination were used to evaluate the teaching effect of the above two teaching modes.Results:In the periodical achievement test, the participatory bilingual teaching group had significantly higher scores than the cramming teaching group in terms of mean score, case analysis, and English questions [seven-year program: (82.13±10.72), (35.74±4.13), and (23.03±3.40) vs. (79.21±11.31), (33.86±5.23), and (22.12±2.75), P<0.05; five-year program: (78.66±12.75), (34.30±5.59), and (22.45±2.91) vs. (75.29±10.81), (32.70±6.04), and (21.36±3.09), P<0.05]. The questionnaire survey showed that participatory bilingual teaching had a better degree of satisfaction than cramming teaching. The participatory bilingual teaching group had a better score than the cramming teaching group in the final examination, but with no significant difference between the two groups. Conclusions:In the teaching of nuclear medicine, the participatory bilingual teaching mode can significantly improve teaching effect and achieve the teaching goal efficiently.

Objective To investigate the effect of Yigong San(YGS)on learning and memory abilities of rats with lipopolysaccharide(LPS)-induced cognitive decline and explore its possible mechanism in light of intestinal microbiota.Methods Forty SD rats were randomly divided into control group,model group,donepezil(1.3 mg/kg)group,and high-dose(5.25 g/kg)and low-dose(2.63 g/kg)YGS treatment groups.After 24 days of treatment with the corresponding drugs or water by gavage,the rats in the latter 4 groups received an intraperitoneal injection of LPS(0.5 mg/kg)to establish models of Alzheimer's disease(AD).Water maze test and HE staining were used to evaluate the changes in learning and memory abilities and pathomorphology of the hippocampus.The changes in gut microbial species of the rats were analyzed with 16S rRNA sequencing,and the levels of IL-6,TNF-α,and IL-1β in the brain tissue and serum were detected using ELISA.Results Compared with the AD model group,the YGS-treated rats showed significantly shortened escape latency on day 5 after modeling,reduced neuronal degeneration and necrosis in the hippocampus,lowered pathological score of cell damage,and decreased levels IL-6,TNF-α and IL-1β in the brain tissue and serum.The YGS-treated rats showed also obvious reduction of Alpha diversity indicators(ACE and Chao1)of intestinal microbiota with significantly increased abundance of Prevotellaceae species at the family level and decreased abundance of Desulfovibrionaceae,which were involved in such metabolic signaling pathways as cell community prokaryotes,membrane transport,and energy metabolism.Conclusion YGS improves learning and memory abilities and hippocampal pathomorphology in AD rat models possibly by regulating the abundance of intestinal microbial species such as Prevotellaceae to affect the metabolic pathways for signal transduction,cofactors,and vitamin metabolism.

Objective To explore the mechanism by which Yigong San(YGS)improves learning and memory abilities of APP/PS1 transgenic mice in light of cerebral fluid metabolism regulation.Methods Three-month-old male APP/PS1 transgenic mice and wild-type C57BL/6 mice were both randomized into control group,model group,donepezil(1.67 mg/kg)group,and YGS(7.5 g/kg)group and received the corresponding treatments via gavage once daily for one month.After the treatments,the mice were assessed for learning and memory functions using Morris water maze test and examined for hippocampal and cortical pathologies and amyloid plaques using HE,immunohistochemical and thioflavin S staining;ELISA and Evans blue method were used for detecting Aβ1-40 and Aβ1-42 levels in the brain tissue and serum and assessing blood-brain barrier(BBB)integrity.Immunofluorescence colocalization was used to investigate AQP4 polarization on astrocytes.Western blotting was performed to detect the expressions of VE-cadherin,ZO-1,occludin,β-amyloid precursor protein(APP),BACE1,insulin-degrading enzyme(IDE),LRP1,RAGE,and AQP4 proteins.Results Compared with the control mice,APP/PS1 mice showed significant impairment of learning and memory abilities,increased degeneration or necrosis of hippocampal and cortical neurons,pathological scores,Aβ-positive plaques,elevated Aβ1-40 and Aβ1-42 levels in the brain tissue and serum,increased BBB permeability,upregulated RAGE expression,lowered expressions of VE-cadherin,LRP1,ZO-1,occludin,and AQP4 proteins,and reduced AQP4-expressing GFAP-positive cells.YGS treatment significantly improved the performance of the transgenic mice in Morris water maze test,reduced hippocampal and cortical pathologies and Aβ-positive plaques,and ameliorated the abnormal changes in Aβ1-40 and Aβ1-42 levels,BBB permeability,protein expressions of RAGE,VE-cadherin,LRP1,ZO-1,occludin and AQP4,and the number of AQP4-expressing GFAP-positive cells.Conclusion YGS improves learning and memory changes in APP/PS1 mice by ameliorating neuronal damage and Aβ pathology in the brain and regulating brain fluid metabolism.

Objective To investigate the effect of Yigong San(YGS)on learning and memory abilities of rats with lipopolysaccharide(LPS)-induced cognitive decline and explore its possible mechanism in light of intestinal microbiota.Methods Forty SD rats were randomly divided into control group,model group,donepezil(1.3 mg/kg)group,and high-dose(5.25 g/kg)and low-dose(2.63 g/kg)YGS treatment groups.After 24 days of treatment with the corresponding drugs or water by gavage,the rats in the latter 4 groups received an intraperitoneal injection of LPS(0.5 mg/kg)to establish models of Alzheimer's disease(AD).Water maze test and HE staining were used to evaluate the changes in learning and memory abilities and pathomorphology of the hippocampus.The changes in gut microbial species of the rats were analyzed with 16S rRNA sequencing,and the levels of IL-6,TNF-α,and IL-1β in the brain tissue and serum were detected using ELISA.Results Compared with the AD model group,the YGS-treated rats showed significantly shortened escape latency on day 5 after modeling,reduced neuronal degeneration and necrosis in the hippocampus,lowered pathological score of cell damage,and decreased levels IL-6,TNF-α and IL-1β in the brain tissue and serum.The YGS-treated rats showed also obvious reduction of Alpha diversity indicators(ACE and Chao1)of intestinal microbiota with significantly increased abundance of Prevotellaceae species at the family level and decreased abundance of Desulfovibrionaceae,which were involved in such metabolic signaling pathways as cell community prokaryotes,membrane transport,and energy metabolism.Conclusion YGS improves learning and memory abilities and hippocampal pathomorphology in AD rat models possibly by regulating the abundance of intestinal microbial species such as Prevotellaceae to affect the metabolic pathways for signal transduction,cofactors,and vitamin metabolism.