Circadian rhythms are self-sustaining oscillations within biological systems that play key roles in a diverse multitude of physiological processes.The circadian clock mechanisms in brain and peripheral tissues can oscillate independently or be synchronized/disrupted by external stimuli.Dental enamel is a type of mineralized tissue that forms the exterior surface of the tooth crown.Incremental Retzius lines are readily observable microstructures of mature tooth enamel that indicate the regulation of amelogenesis by circadian rhythms.Teeth enamel is formed by enamel-forming cells known as ameloblasts,which are regulated and orchestrated by the circadian clock during amelogenesis.This review will first examine the key roles of the circadian clock in regulating ameloblasts and amelogenesis.Several physiological processes are involved,including gene expression,cell morphology,metabolic changes,matrix deposition,ion transportation,and mineralization.Next,the potential detrimental effects of circadian rhythm disruption on enamel formation are discussed.Circadian rhythm disruption can directly lead to Enamel Hypoplasia,which might also be a potential causative mechanism of amelogenesis imperfecta.Finally,future research trajectory in this field is extrapolated.It is hoped that this review will inspire more intensive research efforts and provide relevant cues in formulating novel therapeutic strategies for preventing tooth enamel developmental abnormalities.

Objective To detect the expression levels of renal tissue M-type phospholipase A2 receptor 1(PLA2R1) antigen and its antibody in the patients with membranous nephropathy(MN).Methods Fifty-eight cases of biopsy-proved idiopathic membranous nephropathy(IMN),fifteen cases of hepatitis B-associated membranous nephropathy(HBV-MN) and seventeen cases of V type lupus nephritis(V-LN) were selected.Renal tissue PLA2R1 antigen was detected by indirect immunofluorescence and colocaliazed with IgG4.Serum anti-PLA2R1 antibody was simultaneously examined.The expression difference of PLA2R1 antigen and antiPLA2R1 antibody in MN was analyzed.And the differences of clinical data were analyzed between PLA2R1 positive and negative patients.Results The PLA2R1 antibody was not found in the renal tissue and serum of the patients with LN and HBV-MN;PLA2R1 antigen was found in 81.03％ of IMN patients,and its antibody was found in serum of 70.69％ of IMN patients.PLA2R1 antigen and IgG4 co-localization all deposited along glomerular capillary loop presenting as fine granules.The 24 h urine protein level in the patients with PLA2R1 antigen deposition in renal tissues was higher than that in the patients without PLA2R1 deposition (P＜0.05),moreover serum albumin level was lower than that in the patients without PLA2R1 deposition(P＜0.05).Conclusion The sensitivity and specificity of renal tissue PLA2R1 antigen in the diagnosis of IMN are higher.The expression of PLA2R1 antigen in renal tissue by biopsy is significantly correlated with the clinical severity.

A 63-year-old female patient underwent coronary CT angiography and received an intravenous iohexol injection(350 mg/ ml )80 ml as the contrast agent. At the sixth minutes of observation after CT test completion,the patient developed palm itching,bilateral conjunctival congestion and edema, sweating,vertigo,nausea,and vomiting a small amount of gastric contents and then followed by lip cyanosis, facial edema,cold limbs,skin ecchymosis,and bleeding the injection site. Blood gas analysis showed an oxygen saturation of 0. 83 and an oxygen partial pressure of 47 mmHg. About an hour after CT scan,the laboratory test revealed the following levels:blood platelet count 19 × 109 / L,prothrombin time(PT)18 s, and thrombin time( TT)6 s. Treatments with anti-anaphylaxis,coagulation factor supplementation,and correction of acidosis and electrolyte disorder were given. After 7. 5 hours after CT scan,her blood platelet count was 8 ×109 / L. The next day,large pieces of skin ecchymosis appeared in many parts of her body,a body temperature reached 38. 1 ℃ and a blood platelet count was 6 × 109 / L. Symptomatic and supportive therapy was continued and her condition gradually improved. On day 4,she presented with normal temperature,disappeared facial edema,and relief of skin ecchymosis. On day 6,her level of blood platelet and all the values of coagulation functions returned to normal.

A 63-year-old female patient underwent coronary CT angiography and received an intravenous iohexol injection(350 mg/ ml )80 ml as the contrast agent. At the sixth minutes of observation after CT test completion,the patient developed palm itching,bilateral conjunctival congestion and edema, sweating,vertigo,nausea,and vomiting a small amount of gastric contents and then followed by lip cyanosis, facial edema,cold limbs,skin ecchymosis,and bleeding the injection site. Blood gas analysis showed an oxygen saturation of 0. 83 and an oxygen partial pressure of 47 mmHg. About an hour after CT scan,the laboratory test revealed the following levels:blood platelet count 19 × 109 / L,prothrombin time(PT)18 s, and thrombin time( TT)6 s. Treatments with anti-anaphylaxis,coagulation factor supplementation,and correction of acidosis and electrolyte disorder were given. After 7. 5 hours after CT scan,her blood platelet count was 8 ×109 / L. The next day,large pieces of skin ecchymosis appeared in many parts of her body,a body temperature reached 38. 1 ℃ and a blood platelet count was 6 × 109 / L. Symptomatic and supportive therapy was continued and her condition gradually improved. On day 4,she presented with normal temperature,disappeared facial edema,and relief of skin ecchymosis. On day 6,her level of blood platelet and all the values of coagulation functions returned to normal.