Longitudinal bone growth relies on endochondral ossification in the cartilaginous growth plate,where chondrocytes accumulate and synthesize the matrix scaffold that is replaced by bone.The chondroprogenitors in the re...Longitudinal bone growth relies on endochondral ossification in the cartilaginous growth plate,where chondrocytes accumulate and synthesize the matrix scaffold that is replaced by bone.The chondroprogenitors in the resting zone maintain the continuous turnover of chondrocytes in the growth plate.Malnutrition is a leading cause of growth retardation in children;however,after recovery from nutrient deprivation,bone growth is accelerated beyond the normal rate,a phenomenon termed catch-up growth.Although nutritional status is a known regulator of long bone growth,it is largely unknown whether and how chondroprogenitor cells respond to deviations in nutrient availability.Here,using fate-mapping analysis in Axin2CreERT2 mice,we showed that dietary restriction increased the number of Axin2+chondroprogenitors in the resting zone and simultaneously inhibited their differentiation.Once nutrient deficiency was resolved,the accumulated chondroprogenitor cells immediately restarted differentiation and formed chondrocyte columns,contributing to accelerated growth.Furthermore,we showed that nutrient deprivation reduced the level of phosphorylated Akt in the resting zone and that exogenous IGF-1 restored the phosphorylated Akt level and stimulated differentiation of the pooled chondroprogenitors,decreasing their numbers.Our study of Axin2CreERT2 revealed that nutrient availability regulates the balance between accumulation and differentiation of chondroprogenitors in the growth plate and further demonstrated that IGF-1 partially mediates this regulation by promoting the committed differentiation of chondroprogenitor cells.展开更多
BACKGROUND Salivary duct carcinoma(SDC)is a rare,extremely aggressive malignancy that arises in the submandibular gland.It can metastasize locally early and therefore is an important differential diagnosis of metastat...BACKGROUND Salivary duct carcinoma(SDC)is a rare,extremely aggressive malignancy that arises in the submandibular gland.It can metastasize locally early and therefore is an important differential diagnosis of metastatic disease in cervical lymph nodes or specific lymphadenitis such as tuberculous cervical lymphadenitis.CASE SUMMARY We report a case of SDC in the submandibular gland that presented diagnostic difficulty.The lesion was coincidentally discovered through examination of the radiolucent area of the maxilla.Imaging failed to confirm the possibility of specific inflammation,leading us to execute an open biopsy to verify the diagnosis.The surgical specimen showed that the submandibular gland was primarily replaced with a calcified body.Following histological analysis and confirmation,we performed surgical resection,radiotherapy,and various chemotherapies.CONCLUSION Radiographic imaging characteristics of lymph node metastases of salivary gland cancer,especially of SDC,may resemble other cervical lymphadenitis;calcification at the submandibular gland is the landmark of SDC occurring at the submandibular gland.展开更多
基金partially supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under Award Number R01AR062908(to MEI),R01AR056837(to MI),R01AR073181(to SO),and R21AR077654(to SO)the departmental fund of the University of Maryland(to MI,ME-I)。
文摘Longitudinal bone growth relies on endochondral ossification in the cartilaginous growth plate,where chondrocytes accumulate and synthesize the matrix scaffold that is replaced by bone.The chondroprogenitors in the resting zone maintain the continuous turnover of chondrocytes in the growth plate.Malnutrition is a leading cause of growth retardation in children;however,after recovery from nutrient deprivation,bone growth is accelerated beyond the normal rate,a phenomenon termed catch-up growth.Although nutritional status is a known regulator of long bone growth,it is largely unknown whether and how chondroprogenitor cells respond to deviations in nutrient availability.Here,using fate-mapping analysis in Axin2CreERT2 mice,we showed that dietary restriction increased the number of Axin2+chondroprogenitors in the resting zone and simultaneously inhibited their differentiation.Once nutrient deficiency was resolved,the accumulated chondroprogenitor cells immediately restarted differentiation and formed chondrocyte columns,contributing to accelerated growth.Furthermore,we showed that nutrient deprivation reduced the level of phosphorylated Akt in the resting zone and that exogenous IGF-1 restored the phosphorylated Akt level and stimulated differentiation of the pooled chondroprogenitors,decreasing their numbers.Our study of Axin2CreERT2 revealed that nutrient availability regulates the balance between accumulation and differentiation of chondroprogenitors in the growth plate and further demonstrated that IGF-1 partially mediates this regulation by promoting the committed differentiation of chondroprogenitor cells.
文摘BACKGROUND Salivary duct carcinoma(SDC)is a rare,extremely aggressive malignancy that arises in the submandibular gland.It can metastasize locally early and therefore is an important differential diagnosis of metastatic disease in cervical lymph nodes or specific lymphadenitis such as tuberculous cervical lymphadenitis.CASE SUMMARY We report a case of SDC in the submandibular gland that presented diagnostic difficulty.The lesion was coincidentally discovered through examination of the radiolucent area of the maxilla.Imaging failed to confirm the possibility of specific inflammation,leading us to execute an open biopsy to verify the diagnosis.The surgical specimen showed that the submandibular gland was primarily replaced with a calcified body.Following histological analysis and confirmation,we performed surgical resection,radiotherapy,and various chemotherapies.CONCLUSION Radiographic imaging characteristics of lymph node metastases of salivary gland cancer,especially of SDC,may resemble other cervical lymphadenitis;calcification at the submandibular gland is the landmark of SDC occurring at the submandibular gland.
