Tryptophan is an essential amino acid in all animals. After being metabolized through three pathways in the body, it generates many bioactive metabolites, which affect the physiological processes of the body and provide a basis for potential therapeutic targets of diseases, especially the Kynurenine pathway. This article introduces the roles of the three metabolic pathways of tryptophan in the occurrence and development of ulcerative colitis and colitis-associated colon cancer, with particular attention to the role of the Kynurenine pathway in immune regulation and its potential contradictory effects on ulcerative colitis and colitis-associated colon cancer.

Tryptophan is an essential amino acid in all animals. After being metabolized through three pathways in the body, it generates many bioactive metabolites, which affect the physiological processes of the body and provide a basis for potential therapeutic targets of diseases, especially the Kynurenine pathway. This article introduces the roles of the three metabolic pathways of tryptophan in the occurrence and development of ulcerative colitis and colitis-associated colon cancer, with particular attention to the role of the Kynurenine pathway in immune regulation and its potential contradictory effects on ulcerative colitis and colitis-associated colon cancer.

Objective To investigate the clinicopathological features and key points of diagnosis and treatment of malignant perivascular epithelioid cell tumor(PEComa)to increase awareness of the disease.Methods The clinicopathological data of 2 patients with malignant PEComa treated in our hospital were retrospectively analyzed,and relevant literatures were reviewed.Results Both patients were male,aged 53 and 16 years,respectively.The sites of occurrence were in the retroperitoneum and pelvis,respectively.Both tumors were resected surgically,and the diagnosis was confirmed with postoperative pathology.Under the microscope,the tumor tissue of one patient was mainly composed of smooth muscle-like cells,and that of the other patient was composed of epithelioid cells,both showing pathological mitotic images and expressing HMB45,Melan-A,SMA and CD34,no tumor recurrence or metastasis was observed during the follow-up.The literatures collected involved 15 patients with retroperitoneal or pelvic PEComa,including 3 males and 12 females,of which 9 were malignant.The clinical manifestations were abdominal pain,bloating,or lower back pain.Some cases were detected during physical examinations.Conclusion Malignant PEComa is difficult to be diagnosed before surgery and easy to be misdiagnosed.The confirmed diagnosis depends on the postoperative pathological results.The preferred treatment is complete resection of tumor.Long-term follow-up is needed.

Objective:To provide scientific basis for pilots′ hypoxia training by comparing and analyzing the effects of hypoxia training under normobaric and hypobaric environments.Methods:Forty-two healthy subjects were selected. The pilot reduced oxygen breathing device and hypobaric chamber were used to simulate 7 500 m hypoxia training, and blood oxygen saturation, heart rate, respiratory rate and hypoxia endurance time were monitored and recorded. The hypoxia symptom questionnaire was filled out by the subjects after 2 training sessions. The hypoxia endurance time and hypoxia tolerance grade of normobaric and hypobaric hypoxia training were analyzed, and the differences of blood oxygen saturation and hypoxia symptoms were compared between 2 hypoxia trainings.Results:Forty-two subjects completed the normobaric and hypobaric hypoxia trainings. The survival curve analysis of hypoxia endurance time showed that the median hypoxia endurance time of normobaric and hypobaric hypoxia training was [3.17(2.70, 3.64)] min and [3.67(3.46, 3.88)] min respectively, with no significant difference ( P>0.05). There was no significant difference in the grade distribution of hypoxia tolerance between 2 hypoxia trainings ( P>0.05). The blood oxygen saturation curves of 2 hypoxia trainings were basically consistent. There was no significant difference between 2 hypoxia trainings on blood oxygen saturation, heart rate and respiratory rate (all P>0.05). There were significant differences in difficulty in calculation, difficulty in concentration and with palpitation ( χ2=4.81, 3.97, 3.98, P=0.028, 0.046, 0.046). Conclusions:The analysis showed that most physiological responses and subjective symptoms of pilots are quite similar in the normobaric and hypobaric hypoxia training at simulated 7 500 m. Both normobaric and hypobaric exposures show the similar hypoxia training effect.

Postsurgical hypoparathyroidism is a common cause of hypoparathyroidism, with a variety of clinical manifestations. It is life-threatening in acute and severe cases, and may lead to poor quality of life in chronic patients. It is imperative to consistently enhance the identification and governance of such circumstance. Focusing on the pathophysiological changes, clinical and biochemical features, acute and chronic treatments of postsurgical hypoparathyroidism, a consensus was developed by domestic experts from surgery, endocrinology and nephrology.

Objective:To provide scientific basis for pilots′ hypoxia training by comparing and analyzing the effects of hypoxia training under normobaric and hypobaric environments.Methods:Forty-two healthy subjects were selected. The pilot reduced oxygen breathing device and hypobaric chamber were used to simulate 7 500 m hypoxia training, and blood oxygen saturation, heart rate, respiratory rate and hypoxia endurance time were monitored and recorded. The hypoxia symptom questionnaire was filled out by the subjects after 2 training sessions. The hypoxia endurance time and hypoxia tolerance grade of normobaric and hypobaric hypoxia training were analyzed, and the differences of blood oxygen saturation and hypoxia symptoms were compared between 2 hypoxia trainings.Results:Forty-two subjects completed the normobaric and hypobaric hypoxia trainings. The survival curve analysis of hypoxia endurance time showed that the median hypoxia endurance time of normobaric and hypobaric hypoxia training was [3.17(2.70, 3.64)] min and [3.67(3.46, 3.88)] min respectively, with no significant difference ( P>0.05). There was no significant difference in the grade distribution of hypoxia tolerance between 2 hypoxia trainings ( P>0.05). The blood oxygen saturation curves of 2 hypoxia trainings were basically consistent. There was no significant difference between 2 hypoxia trainings on blood oxygen saturation, heart rate and respiratory rate (all P>0.05). There were significant differences in difficulty in calculation, difficulty in concentration and with palpitation ( χ2=4.81, 3.97, 3.98, P=0.028, 0.046, 0.046). Conclusions:The analysis showed that most physiological responses and subjective symptoms of pilots are quite similar in the normobaric and hypobaric hypoxia training at simulated 7 500 m. Both normobaric and hypobaric exposures show the similar hypoxia training effect.

Hypercalcemia, a common metabolic complication of malignancies, often referred to as hypercalcemia of malignancy(HCM), is associated with a high incidence and mortality rate. In 2023, the American Society for Bone and Mineral Research and the European Society of Endocrinology released the Treatment of Hypercalcemia of Malignancy in Adults: An Endocrine Society Clinical Practice Guideline. This guideline aimed to address key clinical issues related to adult HCM, refractory and recurrent hypercalcemia, hypercalcemia associated with calcitriol, and hypercalcemia caused by adult parathyroid cancer. This article provides an overview of this guideline and offers some suggestions for managing related conditions in China.

Objective:To evaluate and compare the clinical value of unadjusted fracture risk assessment tool(FRAX) and adjusted FRAX in predicting the risk of hip fracture in patients with type 2 diabetes(T2DM).Methods:In this 10-year retrospective cohort study, 1 730 patients with T2DM were collected from August 2009 to July 2013. The 10-year risk of hip fracture was calculated using the China FRAX model. Hip fracture events during the follow-up period were collected through electronic medical records and telephone interviews. The value of FRAX and adjusted FRAX in predicting the risk of hip fracture in T2DM patients was evaluated from two aspects of discrimination and calibration. Cox regression model was used to investigate the relationship between diabetes related factors and hip fracture.Results:A total of 39 participants(2.3%) experienced hip fracture during a median follow-up of 10 years. The area under the curve of unadjusted FRAX was 0.760, but the calibration ability was poor [calibration χ2: 75.78, P<0.001; calibration ratio(observation/prediction): 3.97(95% CI 2.76~5.17)]. There was no significant improvement in calibration ability of adjusted FRAX. After adjustment for unadjusted or adjusted hip fracture probability calculated by FRAX(FRAX-HF), duration, estimated glomerular filtration rate, insulin use, cerebrovascular diseases, and diabetic peripheral neuropathy were significantly associated with an increased risk of hip fracture( P<0.05). Conclusion:The FRAX tool significantly underestimated the risk of hip fracture in T2DM patients, and there was still significantly underestimation after adjustment due to the failure to eliminate the influence of diabetes-related factors such as disease duration and peripheral neuropathy.

Objective:To evaluate the protection performance of military transport aircraft oxygen system for aircrew and provide the physiological tests basis for product design finalization.Methods:Four dummies and 4 healthy volunteers who were equipped with individual protection equipment and military transport aircraft oxygen system completed 4 tests in altitude chamber including the oxygen supply performance physical test of oxygen system, the rapid decompression physical test of oxygen system, the physiological tests of oxygen continuously supplying for 6 h and oxygen supply performance test in rapid decompression at 12.0 km. Oxygen concentration, respiratory resistance, safety pressure, peak value, peak duration and steady pressure of mask under rapid decompression were tested. Electrocardiograph and oxygen saturation of volunteers were monitored.Results:The oxygen partial pressure provided by military transport aircraft oxygen system under 12.0 km was ≥19.1 kPa corresponding to the respiration ventilation volume of 20 L/min of dummy. The expiratory resistance was no higher than 441.3 Pa and the inspiration resistance was no higher than 490.3 Pa before the safety pressure connected. The peak pressure value in rapid decompression with 1.0 L lung volume of dummy was no higher than 5.8 kPa. The oxygen partial pressure provided by military transport aircraft oxygen system for volunteers was over 21.9 kPa in the 6 h cruising flight. All 4 volunteers successfully completed the rapid decompression physiological tests at 12.0 km with good subjective and objective responses.Conclusions:The protection performance of military transport aircraft oxygen system for aircrew can provide enough protection against the hypoxia up to 12.0 km

Objective To investigate the effect and underlying mechanism of Qingguang’an Granules (青光安颗粒剂, QGAG) on mitochondrial autophagy (mitophagy) of retinal ganglion cells (RGCs) in rats with chronic ocular hypertension (COH). Methods Sixty Sprague Dawley (SD) rats, half males and half females, were randomly assigned to three groups: the control, model, and QGAG (2.5 g/kg) groups, with 20 rats in each group. Rats’ model of COH was established by cauterizing episcleral veins in the model group and QGAG group. Three weeks after successful modeling, rats in the QGAG group were intragastrically administered with QGAG, while rats in the control group and the model group received an equal dose of normal saline. After three months of intragastric administration, intraocular pressure (IOP) of all rats was measured. The mitophagy was monitored by the immunofluorescence method, the mitochondrial membrane potential was measured using the JC-1 method, and the morphological changes of mitophagy in RGCs were observed by transmission electron microscopy. Meanwhile, rat RGCs were labeled using the fluorescent gold method, and RGCs density in each group was calculated. Moreover, RGCs apoptosis was observed by TdT-mediated dUTP Nick-End Labeling (TUNEL) assay. Finally, the expression levels of Parkin, optineurin, microtubule-associated protein 1 light chain 3-II/microtubule-associated protein 1 light chain 3-I (LC3-II/LC3-I), recombinant lysosomal associated membrane protein 1 (LAMP1), and B-cell lymphoma-2 (Bcl-2) in RGCs were determined by Western blot assay. The corresponding mRNAs were detected through quantitative real-time polymerase chain reaction (qRT-PCR). Results The QGAG reduced IOP in COH rats, and inhibited mitophagy and apoptosis of RGCs (P < 0.05). Besides, the QGAG significantly increased the expression levels of Parkin and Bcl-2 (P < 0.05), and inhibited the expression levels of optineurin, LAMP1, and LC3-II/LC3-I (P < 0.05) in RGCs of COH rats. Conclusion The QGAG can inhibit mitophagy in RGCs of COH rats and show a protective effect against optic nerve damage caused by glaucoma, which may be mediated through the mitophagy ubiquitination via the Parkin/PINK1-related pathway.