Real-time artificial intelligence predicts adverse outcomes in acute pancreatitis in the emergency department: Comparison with clinical decision rule

OBJECTIVE

Artificial intelligence (AI) prediction is increasingly used for decision making in health care, but its application for adverse outcomes in emergency department (ED) patients with acute pancreatitis (AP) is not well understood. This study aimed to clarify this aspect.

METHODS

Data from 8274 ED patients with AP in three hospitals from 2009 to 2018 were analyzed. Demographic data, comorbidities, laboratory results, and adverse outcomes were included. Six algorithms were evaluated, and the one with the highest area under the curve (AUC) was implemented into the hospital information system (HIS) for real-time prediction. Predictive accuracy was compared between the AI model and Bedside Index for Severity in Acute Pancreatitis (BISAP).

RESULTS

The mean ± SD age was 56.1 ± 16.7 years, with 67.7% being male. The AI model was successfully implemented in the HIS, with Light Gradient Boosting Machine (LightGBM) showing the highest AUC for sepsis (AUC 0.961) and intensive care unit (ICU) admission (AUC 0.973), and eXtreme Gradient Boosting (XGBoost) showing the highest AUC for mortality (AUC 0.975). Compared to BISAP, the AI model had superior AUC for sepsis (BISAP 0.785), ICU admission (BISAP 0.778), and mortality (BISAP 0.817).

CONCLUSIONS

The first real-time AI prediction model implemented in the HIS for predicting adverse outcomes in ED patients with AP shows favorable initial results. However, further external validation is needed to ensure its reliability and accuracy.

[Use of the ETV6/RUNX1 probe to verify the performance of the fluorescence in situ hybridization probe before clinical detection]

Objective: To explore the standardized performance of a FISH probe before clinical detection. Methods: The probe sensitivity and specificity of ETV6/RUNX1 were analyzed via interphase and metaphase FISH in 20 discarded healthy bone marrow samples. The threshold system of the probe was established using an inverse beta distribution, and an interpretation standard was established. Finally, a parallel-controlled polymerase chain reaction detection study was conducted on 286 bone marrow samples from patients at our hospital. The clinical sensitivity, specificity, and diagnostic coincidence rate of ETV6/RUNX1 FISH detection were analyzed, and the diagnostic consistency of the two methods was analyzed by the kappa test. Results: The probe sensitivity and specificity of the ETV6/RUNX1 probe were 98.47% and 100%, respectively. When 50, 100, and 200 cells were counted, the typical positive signal pattern cutoffs were 5.81%, 2.95%, and 1.49%, respectively, and the atypical positive signal pattern cutoffs were 13.98%, 9.75%, and 6.26%, respectively. The clinical sensitivity of FISH was 96.1%, clinical specificity was 99.6%, diagnostic coincidence rate was 99.00%, diagnostic consistency test kappa value was 0.964, and P value was <0.001. Conclusion: For FISH probes without a national medical device registration certificate, standardized performance verification and methodology performance verification can be performed using laboratory developed test verification standards to ensure a reliable and accurate reference basis for clinical diagnosis and treatment.

Real-time artificial intelligence system for bacteremia prediction in adult febrile emergency department patients

BACKGROUND

Artificial intelligence (AI) holds significant potential to be a valuable tool in healthcare. However, its application for predicting bacteremia among adult febrile patients in the emergency department (ED) remains unclear. Therefore, we conducted a study to provide clarity on this issue.

METHODS

Adult febrile ED patients with blood cultures at Chi Mei Medical Center were divided into derivation (January 2017 to June 2019) and validation groups (July 2019 to December 2020). The derivation group was utilized to develop AI models using twenty-one feature variables and five algorithms to predict bacteremia. The performance of these models was compared with qSOFA score. The AI model with the highest area under the receiver operating characteristics curve (AUC) was chosen to implement the AI prediction system and tested on the validation group.

RESULTS

The study included 5,647 febrile patients. In the derivation group, there were 3,369 patients with a mean age of 61.4 years, and 50.7% were female, including 508 (13.8%) with bacteremia. The model with the best AUC was built using the random forest algorithm (0.761), followed by logistic regression (0.755). All five models demonstrated better AUC than the qSOFA score (0.560). The random forest model was adopted to build a real-time AI prediction system integrated into the hospital information system, and the AUC achieved 0.709 in the validation group.

CONCLUSION

The AI model shows promise to predict bacteremia in adult febrile ED patients; however, further external validation in different hospitals and populations is necessary to verify its effectiveness.

Implementing a Novel Machine Learning System for Nutrition Education in Diabetes Mellitus Nutritional Clinic: Predicting 1-Year Blood Glucose Control

(1) Background: Persistent hyperglycemia in diabetes mellitus (DM) increases the risk of death and causes cardiovascular disease (CVD), resulting in significant social and economic costs. This study used a machine learning (ML) technique to build prediction models with the factors of lifestyle, medication compliance, and self-control in eating habits and then implemented a predictive system based on the best model to forecast whether blood glucose can be well-controlled within 1 year in diabetic patients attending a DM nutritional clinic. (2) Methods: Data were collected from outpatients aged 20 years or older with type 2 DM who received nutrition education in Chi Mei Medical Center. Multiple ML algorithms were used to build the predictive models. (3) Results: The predictive models achieved accuracies ranging from 0.611 to 0.690. The XGBoost model with the highest area under the curve (AUC) of 0.738 was regarded as the best and used for the predictive system implementation. SHAP analysis was performed to interpret the feature importance in the best model. The predictive system, evaluated by dietitians, received positive feedback as a beneficial tool for diabetes nutrition consultations. (4) Conclusions: The ML prediction model provides a promising approach for diabetes nutrition consultations to maintain good long-term blood glucose control, reduce diabetes-related complications, and enhance the quality of medical care.

[Current status and prospects of neoadjuvant therapy for resectable pancreatic cancer]

Pancreatic cancer is a highly malignant tumor. About 75% of patients with pancreatic cancer who underwent radical surgical resection will still experience postoperative recurrence. Neoadjuvant therapy could improve outcomes in patients with borderline resectable pancreatic cancer,has become a consensus;however it is still controversial in resectable pancreatic cancer. Limited high-quality randomized controlled trial studies support the routine initiation of neoadjuvant therapy in resectable pancreatic cancer. With the development of new technologies, such as next-generation sequencing, liquid biopsy, imaging omics, and organoids, patients are expected to benefit from the precision screening of potential candidates for neoadjuvant therapy and individualized treatment strategy.

Using an Artificial Intelligence Approach to Predict the Adverse Effects and Prognosis of Tuberculosis

Background: Tuberculosis (TB) is one of the leading causes of death worldwide and a major cause of ill health. Without treatment, the mortality rate of TB is approximately 50%; with treatment, most patients with TB can be cured. However, anti-TB drug treatments may result in many adverse effects. Therefore, it is important to detect and predict these adverse effects early. Our study aimed to build models using an artificial intelligence/machine learning approach to predict acute hepatitis, acute respiratory failure, and mortality after TB treatment. Materials and Methods: Adult patients (age ≥ 20 years) who had a TB diagnosis and received treatment from January 2004 to December 2021 were enrolled in the present study. Thirty-six feature variables were used to develop the predictive models with AI. The data were randomly stratified into a training dataset for model building (70%) and a testing dataset for model validation (30%). These algorithms included XGBoost, random forest, MLP, light GBM, logistic regression, and SVM. Results: A total of 2248 TB patients in Chi Mei Medical Center were included in the study; 71.7% were males, and the other 28.3% were females. The mean age was 67.7 ± 16.4 years. The results showed that our models using the six AI algorithms all had a high area under the receiver operating characteristic curve (AUC) in predicting acute hepatitis, respiratory failure, and mortality, and the AUCs ranged from 0.920 to 0.766, 0.884 to 0.797, and 0.834 to 0.737, respectively. Conclusions: Our AI models were good predictors and can provide clinicians with a valuable tool to detect the adverse prognosis in TB patients early.

Anesthesia management for cesarean section in a pregnant woman with odontogenic infection: A case report

BACKGROUND

In recent years, people have paid more attention to oral health with the development of stomatology. Due to the various physiological changes during pregnancy, such as changing hormone levels and immune functions, oral diseases have a high incidence during pregnancy, and the prevention and treatment of oral diseases have also received the attention of both dentists and obstetricians. However, the anesthetic management of pregnant patients with oral disease, especially severe maxillofacial infections, and patients who need surgical treatment or have obstetric emergencies and need to terminate their pregnancy is not clear.

CASE SUMMARY

This article describes a parturient patient with a severe masseteric space infection who had an emergency cesarean section.

CONCLUSION

This case report aims to discuss the important anesthetic considerations for these patients.

Shear stress-induced MMP1 and PDE2A expressions in coronary atherosclerosis

AIM

Biomechanical stress plays an essential role in coronary atherosclerosis (CAS), however, inter-relations between mechanical conditions and gene expressions remain unclear.

METHODS

We constructed finite element model of CAS to map human wall shear stress (WSS). Biopsy aortic tissue samples were obtained from 3 CAS patients. Gene expression pattern in CAS was analyzed by GEO datasets. Immunofluorescence staining and western blot confirmed protein expression and localization.

RESULTS

Peak WSS was significantly increased in the vessel stenosis of CAS at 0.25 s (mean 55.1 Pa). Analyses results of GSE76275 showed matrix metalloproteinases1 (MMP1) and phosphodiesterase-2A (PDE2A) up-regulation in endothelial shear responsiveness, which was further validated and localized in vascular endothelial cells, smooth muscle cells and other cells by double immunofluorescence staining. Western blotting assay demonstrated up-regulation of MMP1 and PDE2A expression dependent on the WSS.

CONCLUSIONS

MMP1 and PDE2A up-regulations rely on increased WSS in development and risk of CAS, suggesting that their elevation may be potential target for diagnosis and treatment (Fig. 3, Ref. 28).

Predictors of catheter-related bladder discomfort after gynaecological surgery

BACKGROUND

Urinary catheterization is universally used during surgery, and the incidence of postoperative catheter-related bladder discomfort (CRBD) is very high during recovery. We conducted this study to identify the incidence and predictors of postoperative CRBD after gynaecological surgery in the post-anesthesia care unit (PACU).

METHODS

This was a prospective observational study. Patients undergoing gynaecological surgery under general anesthesia with intra-operative urinary catheterization were enrolled. We collected the clinical data, incidence and severity of CRBD, and postoperative pain for the patients. Predictive factors of CRBD were analysed by univariate and multivariate analysis.

RESULTS

A total of 407 patients were included in this study. The incidence of CRBD after gynaecological surgery was 64.6% (mild CRBD: 22.8%; moderate CRBD: 34.2%; and severe CRBD: 7.6%). Univariate analysis showed that age, type of surgery, type of laparoscopic surgery, additional analgesics, and postoperative pain were influencing factors for CRBD. Based on multivariate logistic regression analysis, age ≥ 50 years, uterus-related laparoscopic surgery, and lack of additional analgesics were independent predictors of moderate or severe CRBD.

CONCLUSIONS

This observational study revealed that the incidence of CRBD after gynaecological surgery in PACU was very high. Age ≥ 50 years, uterus-related laparoscopic surgery, and lack of additional analgesics were independent predictors of CRBD.

TRIAL REGISTRATION

ChiCTR1800016390. Registered on 30 May 2018.

[Circulating tumor cells in pancreatic cancer patients: progression in the detection methods and clinical application]

Circulating tumor cells (CTC) disseminate from primary tumors by undergoing epithelial mesenchymal transition that allow their entry into the circulation to drive metastatic formation in pancreatic cancer patients.Technological advances in detection and characterization of CTC are conducive to the early diagnosis, differential diagnosis, monitoring disease progression and predicating the probability of canceration or the chemotherapeutic efficacy. Nowadays, detection methods of CTC can be based on immunomagnetic beads technique, cell filtration or microfluidic chips technology, but there are great differences in the sample throughput, CTC recovery rate, purity, and CTC viability among them.Owing to the dilemma in detection methods, the intrinsic relevance between the biological characteristics of CTC and clinical manifestations is still not exactly elucidated. By the improved methodology, next generation sequencing technology and exploring the technique for culturing CTC in vitro and establishing xenotransplanted tumor model in nude mice, more and more biological information will be revealed, and finally, individualized treatment is achieved.

Comparison of intravenous lidocaine and dexmedetomidine infusion for prevention of postoperative catheter-related bladder discomfort: a randomized controlled trial

BACKGROUND

Catheter-related bladder discomfort (CRBD) frequently occurs during recovery in patients who undergo intra-operative urinary catheterization. We conducted this study to compare the effect of intravenous lidocaine and dexmedetomidine infusion for preventing CRBD.

METHODS

120 patients undergoing elective open abdominal hysterectomy or hysteromyomectomy requiring urinary bladder catheterization were randomly allocated into three groups of 40 each. Group L received a 2 mg/kg lidocaine bolus followed by infusion of 1.5 mg/kg/h; Group D received a 0.5 μg/kg dexmedetomidine bolus followed by infusion of 0.4 μg/kg/h; Group C received a bolus and infusion of normal saline of equivalent volume. The incidence and different severity (mild, moderate, and severe) of CRBD were assessed on arrival in the postanaesthesia care unit at 0, 1, 2, and 6 h postoperatively.

RESULTS

The incidence of CRBD was significantly lower in Group L and Group D compared with Group C at 0, 1, and 2 h. However, there was no significant difference among the three groups regarding the different severity of CRBD at all time points. The requirement of rescue tramadol for CRBD was lower in group L and group D than in group C. The incidence of sedation was significantly higher in Group D compared to Group L and Group C, though no difference in other adverse effects was observed.

CONCLUSIONS

Intravenous lidocaine and dexmedetomidine infusion reduced the incidence of CRBD as well as the additional tramadol requirement for CRBD, but had no effect on the different severity of CRBD.

TRIAL REGISTRATION

ChiCTR-INR-16009162 . Registered on 5 September 2016.

[Protein-repellent and antibacterial properties of modified orthodontic adhesive]

OBJECTIVE

To develop a novel protein-repellent orthodontic adhesive by incorporating 2-methacryloyloxyethyl phosphorylcholine(MPC).

METHODS

MPC was incorporated into a commercially available orthodontic adhesive(Fuji ORTHO) at 0% (control), 1.5%, 3.0%, and 5.0% by mass. Enamel shear bond strength(SBS) was determined. Protein adsorption onto specimens was determined by a micro bicinchoninic acid method. A dental plaque microcosm biofilm model with human saliva as inoculum was used to investigate biofilm viability.

RESULTS

The SBS was not reduced in the group(3.0% MPC), compared to the control group. The amount of protein adsorption in the group(3.0% MPC) was (0.46±0.06) μg/cm(2) and (4.57 ± 0.42) μg/cm(2) in the control group. Lactic acid production of biofilms in the group(3.0% MPC) was (7.12±1.03) mmol/L and (12.16±1.24) mmol/L in the control group.

CONCLUSIONS

MPC based orthodontic adhesive greatly reduced the protein adsorption and bacterial adhesion, without compromising enamel shear bond strength.

[Liver injury and Nrf2 expression in neonatal rats with hyperoxia]

OBJECTIVE

To investigate the effect of continuous exposure to hyperoxia on livers and changes in nuclear factor erythroid 2-related factor 2 (Nrf2) expression in hepatic tissues in neonatal rats.

METHODS

100 neonatal Sprague-Dawley rats were randomized divided into hyperoxia group (FiO = 95%, O group) and normal control group (FiOG2 = 21%, N group) immediately after birth. Hepatic apoptotic index and Nrf2 expression were detected by immunohistochemical methods on 4 d, 7 d, and 14 d.

RESULTS

Rats with hyperoxia had higher levels of hepatic apoptotic index and Nrf2 expression compared with the controls (P < 0.01). The levels of hepatic apoptotic index and Nrf2 expression in rats with hyperoxia were higher on 7 d and 14 d than those on 4 d (P < 0.01).

CONCLUSION

Continuous exposure to hyperoxia could result in hepatic damage to neonatal rats, with increased expression of Nrf2 as a mechanism of anti-oxidant.

[Protection effect of recombiant human erythropoietin preconditioning against intrauterine hypoxic-ischemic brain injury and its influence on expression of caspase-3 protein in brain tissue]

OBJECTIVE

To investigate the effects of recombine human erythropoietin (rhEPO) on neural cells apoptosis and the expression of Caspase-3 protein in brain tissue of fetal rats after intrauterine hypoxic-ischemic brain injury.

METHODS

Forty-four Sprague-Dawley rats on 19 days of pregnancy were divided into rhEPO treated group, ischemia-reperfusion group and sham-operated group. Intrauterine hypoxic-ischemic injury of fetal rats was induced by bilateral occlusion of the utero-ovarian artery for 20 min. rhEPO (5000 U/kg) was injected into rats through caudal vein in rhEPO treated group while saline was injected into rats in hypoxic-ischemic group 30 min before hypoxic-ischemic injury. The brain samples in rhEPO treated group and hypoxic-ischemic group were obtained at 30 min, 3 h, 6 h, 24 h and 48 h respectively after artery clamping. There was no hypoxic-ischemic injury in sham-operated group, so the brain samples were obtained at 24 hours after sham operation. Neuroapoptosis in brain tissue was measured by TdT mediated dUTP-biotin nick end labeling (Tunel) staining. The expression of Caspase-3 protein was observed by immunohistochemistry.

RESULTS

The number of apoptosis cells in fetal rat hippocampus after intrauterine hypoxic-ischemic increased progressively with reperfusion. Compared with the I/R group, the number of apoptosis cells decreased in rhEPO treated group (P < 0.01). The expression of Caspase-3 increased rapidly after 3 hours from the reperfusion in the I/R group. Compared with the I/R group, there was less expression of Caspase-3 in rhEPO treated group (P < 0.01).

CONCLUSION

rhEPO showed the effects to inhibit the apoptosis of fetal neural cells and the expression of Caspase-3 protein due to intrauterine hypoxic-ischemic brain injury.

[Effect of recombinant human erythropoietin on apoptosis of neural cells in fetal rats after intrauterine hypoxic-ischemic injury]

OBJECTIVE

To investigate the effect of recombine human erythropoietin (rhEPO) on apoptosis of neural cells in fetal rats after intrauterine hypoxic-ischemic injury.

METHODS

Twenty SD rats on 19 days of pregnancy were divided into rhEPO (2500 U/kg, 5000 U/kg, 7500 U/kg) treated groups, ischemia-reperfusion (I/R) group and sham-operated group (4 rats in each group). Intrauterine hypoxic-ischemic injury of fetal rat was induced by bilateral occlusion of utero-ovarian artery for 20 min. rhEPO was injected into the rats in rhEPO treated group through the caudal vein 30 min before hypoxic-ischemic injury while saline was used in the other two groups. There was no hypoxic-ischemic injury in sham-operated group. The death rate of fetal rats was evaluated at 24 h after the operation, and then the brain samples of fetal rats were harvested. The expression of Caspase-3 protein was observed by immunohistochemistry. Neuroapoptosis was measured by TdT mediated dUTP-biotin nick end labeling (TUNEL) staining.

RESULTS

Death rates of fetal rats in rhEPO treated groups decreased compared with the I/R group (P < 0.05). Compared with the I/R group, there was less expression of copious Caspase-3 in rhEPO treated group (P < 0.01). The expression of Caspase-3 was decreased in the rhEPO treated groups with the increase of rhEPO dose (P < 0.01). Compared with the I/R group, the death rate of fetal rats in rhEPO treated groups decreased (P < 0.05), the number of apoptosis cells also decreased obviously (P < 0.01). The anti-apoptosis effect of 5000 U/kg rhEPO was similar to 7500 U/kg rhEPO, but better than 2500 U/kg rhEPO (P < 0.01).

CONCLUSION

rhEPO can inhibit the apoptosis of fetal rat brain cells after intrauterine hypoxic-ischemic injury.

[Erythropoietin through the placenta barrier and fetal blood-brain barrier with transient uteroplacental ischemia]

OBJECTIVE

To observe the permeability of recombinant human erythropoietin through placenta barrier and fetal blood-brain barrier after transient uteroplacental ischemia.

METHODS

Rats on days 19 of pregnancy were divided into rhEPO treated group, ischemia-reperfusion group and sham operated group. Fetal ischemia in rhEPO treated group and ischemia-reperfusion group was induced by bilateral occlusion of the utero-ovarian artery for 20 minutes. Different dosage of 125I-rhEPO (2500 U/kg, 5000 U/kg, 7500 U/kg) was injected into the rats through caudal veins 30 min before injury in rhEPO treated group and sham-operated group. Saline was administered intravenously 30 min before the induction of hypoxic-ischemic injury in ischemia-reperfusion group. The amniotic fluid, placenta and fetal organs including brain, liver, heart, lung and kidney were collected to measure the radioactivity at 24h after injury.

RESULTS

125I-rhEPO was detected in amniotic fluid, placenta and fetal organs. The radioactivity of 125I-rhEPO in these tissues increased gradually with the increased dose injected in rhEPO treated group and sham-operated group. There were significant differences in the radioactivity of 125I-rhEPO between rhEPO treated group and sham-operated group (P < 0.05).

CONCLUSION

The permeability of rhEPO through placental barrier and blood-brain barrier increased under the condition of fetal ischemia and hypoxia.

[Permeability of exogenetic recombine human erythropoietin through placenta barrier to fetal rats with transient uteroplacental ischemia]

OBJECTIVE

To investigate whether recombine human erythropoietin can cross the placenta barrier in rats with transient uteroplacental ischemia.

METHODS

Rats on day 19 of pregnancy were divided into ischemia-reperfusion group, sham-operated group and rhEPO treated group. Fetal ischemia was induced by bilateral occlusion of the utero-ovarian artery for 20 minutes. 125I-rhEPO or saline were administered intravenously 30 min before the induction of hypoxic-ischemic injury. Fetal rat organs were removed to measure the radioactivity post injury.

RESULTS

A small amount of radioactive activity (1.26 +/- 0.28) pg/g was detected in the fetal rats with ischemia-reperfusion. 125I-rhEPO radioactivity increased gradually with time in the placenta, amniotic fluid and fetal tissues of vital organs in the rats of sham-operated group and rhEPO treatment group. There were significant differences in 125I-rhEPO between placental organs and other organs (P < 0.05). The permeability of 125I-rhEPO through the blood brain barrier changed with reperfusion time and peaked about 6 h after reperfusion, and significant differences were found between rhEPO treatment group and sham operation group (P < 0.05).

CONCLUSION

Exogenous rhEPO can cross the placenta barrier and blood-brain barrier and reach hypoxic-ischemic fetal rats.

First Report of Powdery Mildew Caused by Oidium neolycopersici on Tomato in China

Tomato powdery mildew can cause remarkable reduction in fruit size and quality (4). In March of 2008, powdery mildew appeared as circular, white colonies on leaves, petioles, and stems of tomato plants grown in greenhouses in Shangqiu, Henan Province, China. The pathogenic fungus had unbranched conidiophores with an average length of 58.4 μm and width of 5.1 μm. Conidia were hyaline, elliptical, and were borne singly. Average length and width of conidia were 30.6 and 15.1 μm, respectively. Germ tubes were straight and formed at the ends or very close to the ends of conidia. Chasmothecium was not found in the collected samples. Different tomato cultivars and species, including Lycopersicon esculentum Mill (cvs. Moneymaker, Micro-Tom, Zaofen, Fenguo, and Zhongza series), L. peruvianum cv. LA2172, and L. hirsutum cv. G1.1560, were inoculated with a conidial suspension with a concentration of 5 × 10⁴ conidia/ml. Plants developed powdery mildew symptoms as early as 4 days after inoculation. Susceptible symptoms developed on all L. esculentum cultivars, while L. peruvianum LA2172 and L. hirsutum G1.1560 displayed complete resistance, which is similar to the results of Bai et al 2004 (1) and Lindhout and Pet 1990 (3). Morphological characteristics of the pathogen on susceptible genotypes were similar to those from naturally infected plants. On the basis of the characteristics of the asexual stage, the pathogen was identified as an isolate of Oidium neolycopersici L. Kiss, which was confirmed by internal transcribed spacer (ITS) sequence analysis. PCR amplification and sequencing of the ITS region were performed with primers ITS1 and ITS4. The nucleotide sequence was assigned GenBank Accession No. EU486992, which had a 100% homology with 10 ITS sequences of O. neolycopersici in GenBank (Accession Nos. EU047559 to 047568) (2). In Asia, the spread of this pathogen has been recently reported in Japan (2). To our knowledge, this is the first report of tomato powdery mildew in China. Voucher specimens are available at the Specimen Center in the Department of Life Science, Shangqiu Normal University. References: (1) Y. Bai et al. Mol. Plant-Microbe. Interact. 18:354, 2005. (2) T. Jankovics et al. Phytopathology 98:529, 2008. (3) P. Lindhout and G. Pet. Tomato Gen. Coop. Rep. 40:19, 1990. (4) J. M. Whipps et al. Plant Pathol. 47:36, 1998.

Mitochondrial theory of aging matures--roles of mtDNA mutation and oxidative stress in human aging

Mitochondrial theory of aging, a variant of free radical theory of aging, proposes that accumulation of damage to mitochondria and mitochondrial DNA (mtDNA) leads to aging of humans and animals. It has been supported by the observation that mitochondrial function declines and mtDNA mutation increases in tissue cells in an age-dependent manner. Age-related impairment in the respiratory enzymes not only decreases ATP synthesis but also enhances production of reactive oxygen species (ROS) through increased electron leakage in the respiratory chain. Human mtDNA, which is not protected by histones and yet is exposed to high levels of ROS and free radicals in the matrix of mitochondria, is susceptible to oxidative damage and mutation in tissue cells. In the past decade, more than one hundred mtDNA mutations have been found in patients with mitochondrial disease, and some of them also occur in aging human tissues. The incidence and abundance of these mutant mtDNAs are increased with age, particularly in tissues with great demand for energy. On the other hand, recent studies have revealed that the ability of the human cell to cope with oxidative stress is compromised in aging. Comparative analysis of gene expression by microarray technology has shown that a number of genes related to oxidative stress response are altered in aging animals. We discovered that the transcripts of early growth response protein-1, growth arrest and DNA damage-inducible proteins and glutathione S-transferase genes are increased in response to oxidative stress in human skin fibroblasts. Moreover, the activities of Cu,Zn-SOD, catalase and glutathione peroxidase decrease with age, whereas Mn-SOD activity increases with age up to 65 years and slightly declines thereafter in skin fibroblasts. Such an imbalance in the function of antioxidant enzymes may result in excess production of damaging ROS in the cell. This notion is supported by the observation that intracellular levels of H2O2 and oxidative damage to DNA and lipids are significantly increased with age of the fibroblast donor. Furthermore, the mitochondrial pool of reduced glutathione declines and DNA damage is enhanced in aging tissues. Taken together, these observations and our previous findings that mtDNA mutations and oxidative damage are increased in aging human tissues suggest that mitochondrial theory of aging is mature.

Increases of mitochondrial mass and mitochondrial genome in association with enhanced oxidative stress in human cells harboring 4,977 BP-deleted mitochondrial DNA

In order to investigate the effect of aging- and disease-associated deletion of mtDNA on cellular functions, we used cytoplasm fusion to construct a series of the cybrids harboring varying proportions of mtDNA with 4,977 bp deletion from skin fibroblasts of a patient with chronic progressive external ophthalmoplegia. The cybrids were grown in the Dulbecco's modified Eagle medium supplemented with 5% fetal bovine serum, 100 microg/ml pyruvate and 50 microg/ml uridine. The population doubling time was longer for the cybrids containing higher proportions of 4,977 bp-deleted mtDNA. In addition, we found that the respiratory function was decreased with the increase of mtDNA with 4,977 bp deletion in the cybrids. Since impairment of the respiratory system of mitochondria increases the electron leak of the respiratory chain, we further determined the oxidative stress in these cybrids. The results showed that the specific contents of 8-hydroxy 2'-deoxyguanosine and lipid peroxides of the cybrids harboring > 65% of the 4,977 bp-deleted mtDNA were significantly increased as compared with those of the cybrids containing undetectable mutant mtDNA. On the other hand, we found that the mitochondrial mass and the relative content of the mitochondrial genome in the cybrids harboring 4,977 bp-deleted mtDNA were higher than those of the cybrids containing only wild type mtDNA. The relative content of mtDNA was increased 17% and 30%, respectively, in the cybrids harboring 17% and 56% of mtDNA with 4,977 bp deletion. Moreover, both mitochondrial mass and mtDNA content were concurrently increased by treatment of the cybrids with 180 microM of hydrogen peroxide. Taken these findings together, we conclude that increase of mitochondrial mass and mtDNA are the molecular events associated with enhanced oxidative stress in human cells with impaired respiratory function caused by mtDNA deletion.

Oxidative stress in human aging and mitochondrial disease-consequences of defective mitochondrial respiration and impaired antioxidant enzyme system

Respiratory function of mitochondria is compromised in aging human tissues and severely impaired in the patients with mitochondrial disease. A wide spectrum of mitochondrial DNA (mtDNA) mutations has been established to associate with mitochondrial diseases. Some of these mtDNA mutations also occur in various human tissues in an age-dependent manner. These mtDNA mutations cause defects in the respiratory chain due to impairment of the gene expression and structure of respiratory chain polypeptides that are encoded by the mitochondrial genome. Since defective mitochondria generate more reactive oxygen species (ROS) such as O2- and H2O2 via electron leak, we hypothesized that oxidative stress is a contributory factor for aging and mitochondrial disease. This hypothesis has been supported by the findings that oxidative stress and oxidative damage in tissues and culture cells are increased in elderly subjects and patients with mitochondrial diseases. Another line of supporting evidence is our recent finding that the enzyme activities of Cu,Zn-SOD, catalase and glutathione peroxidase (GPx) decrease with age in skin fibroblasts. By contrast, Mn-SOD activity increases up to 65 years of age and then slightly declines thereafter. On the other hand, we observed that the RNA, protein and activity levels of Mn-SOD are increased two- to three-fold in skin fibroblasts of the patients with CPEO syndrome but are dramatically decreased in patients with MELAS or MERRF syndrome. However, the other antioxidant enzymes did not change in the same manner. The imbalance in the expression of these antioxidant enzymes indicates that the production of ROS is in excess of their removal, which in turn may elicit an elevation of oxidative stress in the fibroblasts. Indeed, it was found that intracellular levels of H2O2 and oxidative damage to DNA and lipids in skin fibroblasts from elderly subjects or patients with mitochondrial diseases are significantly increased as compared to those of age-matched controls. Furthermore, Mn-SOD or GPx-1 gene knockout mice were found to display neurological disorders and enhanced oxidative damage similar to those observed in the patients with mitochondrial disease. These observations are reviewed in this article to support that oxidative stress elicited by defective respiratory function and impaired antioxidant enzyme system plays a key role in the pathophysiology of mitochondrial disease and human aging.

[Studies permeation of puerarin and its phospholipid complex through mouse skin in vitro]

OBJECTIVE

To investigate the skin permeation of puerarin and its phospholipid complex and compare the differences between their permeation rates and cumulative permeation amounts.

METHOD

Performing a test of permeation through the mouse skin in vitro in an improved Franz diffusion cell.

RESULT

The cumulative permeation amount of phospholipid complex was higher than that of puerarin in the first hour and then increased slowly, meanwhile the permeation rate of puerarin rose higher than that of the complex.

CONCLUSION

Phospholipid complex of puerarin can permeate through the mouse skin rapidly up to a certain amount in a short time, then begins to release drug slowly and lastingly.

[A study on cultivation techniques for Glycyrrhiza uralensis fisch. in Daxing County area, Beijing]

OBJECTIVE

To study the suitable cultivation techniques for Glycyrrhiza uralensis in the sandy soil in Daxing county area, the Beijing.

METHOD

Small plot trial and Large-scale cultivation in the fields.

RESULT AND CONCLUSION

Uralensis can be cultivated in the sandy soil in Daxing County area, Beijing.

Magnitude of effect of reaction parameters on 2-chlorophenol decomposition by ultrasonic process

In the present work, decomposition of o-chlorophenol (2-cp) was carried out using an ultrasonic process. The extent of 2-cp decomposition depends on several parameters such as ultrasound wave energy (ultrasonic amplitude), addition of hydrogen peroxide (H2O2), pH value (H+ concentration), ionic strength, and initial concentration of 2-cp. The experimental results showed that the decomposition of 2-cp was affected by the various reaction conditions. The profiles of 2-cp decomposition fitted well with the first-order kinetic equation. A linear relationship was obtained between the rate constants of 2-cp decomposition and the varying reaction parameters. The magnitude of effect of reaction parameters such as ultrasonic amplitude, H+ concentration, ionic strength, H2O2 and 2-cp initial concentration on 2-cp decomposition were 0.60, 0.48, 0.19, 0.09 and -0.06, respectively.

Oxidative modification of glutamine synthetase by 2,2'-azobis(2- amidinopropane) dihydrochloride

In the present study, we examined the pattern of protein modification elicited by alkylperoxyl radicals and alkylperoxides. To this end, we exposed glutamine synthetase (GS) and the peptide melittin to solutions containing 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH), which is known to decompose in aqueous, aerobic solutions to yield alkyl radicals and alkylperoxides. Under our conditions, pH 7.4, 37 degrees C, the AAPH-dependent formation of alkylhydroperoxide increased linearly with time and led to 40% inactivation of GS in 1 h and to complete inactivation in 4 h. Complete inactivation was associated with the loss of 2 of 16 histidine residues, 6 of 17 tyrosine residues, 5 of 16 methionine residues, and all of the tryptophan residues (2 residues) per subunit. Inactivation of GS was associated also with some protein fragmentation and the formation of some higher molecular weight aggregates. Exposure of GS to AAPH led also to the generation of protein carbonyl derivatives (0.34 mol/mol subunit) and to formation of a significant amount (0.038 mol/mol subunits) of quinoprotein derivatives. To investigate the mechanism of tryptophan modification, the 26-amino-acid peptide, melittin, which contains one tryptophan but no histidine, tyrosine, or methionine residues, was treated with AAPH. N-Formylkynurenine was identified as the major product of tryptophan oxidation in melittin.

Oxidative damage and mutation to mitochondrial DNA and age-dependent decline of mitochondrial respiratory function

Mitochondrial respiration and oxidative phosphorylation are gradually uncoupled, and the activities of the respiratory enzymes are concomitantly decreased in various human tissues upon aging. An immediate consequence of such gradual impairment of the respiratory function is the increase in the production of the reactive oxygen species (ROS) and free radicals in the mitochondria through the increased electron leak of the electron transport chain. Moreover, the intracellular levels of antioxidants and free radical scavenging enzymes are gradually altered. These two compounding factors lead to an age-dependent increase in the fraction of the ROS and free radical that may escape the defense mechanism and cause oxidative damage to various biomolecules in tissue cells. A growing body of evidence has established that the levels of ROS and oxidative damage to lipids, proteins, and nucleic acids are significantly increased with age in animal and human tissues. The mitochondrial DNA (mtDNA), although not protected by histones or DNA-binding proteins, is susceptible to oxidative damage by the ever-increasing levels of ROS and free radicals in the mitochondrial matrix. In the past few years, oxidative modification (formation of 8-hydroxy-2'-deoxyguanosine) and large-scale deletion and point mutation of mtDNA have been found to increase exponentially with age in various human tissues. The respiratory enzymes containing the mutant mtDNA-encoded defective protein subunits inevitably exhibit impaired respiratory function and thereby increase electron leak and ROS production, which in turn elevates the oxidative stress and oxidative damage of the mitochondria. This vicious cycle operates in different tissue cells at different rates and thereby leads to the differential accumulation of mutation and oxidative damage to mtDNA in human aging. This may also play some role in the pathogenesis of degenerative diseases and the age-dependent progression of the clinical course of mitochondrial diseases.

Isolation of rabbit liver heat shock protein with molecular weight 90 kD (Hsp90) and its interaction with troponin components and calponin

Using a modified method consisting of chromatography on phenyl-Sepharose, Q-Sepharose, and hydroxyapatite, we isolated a highly purified heat shock protein with molecular weight 90 kD (Hsp90) from rabbit liver. The isolated protein was recognized on immunoblot by commercially available monoclonal anti-Hsp90 antibodies. The chromatographic properties, interaction with actin and calmodulin, phosphorylation in the presence of Mg-ATP, and one-dimensional peptide maps of rabbit liver Hsp90 are similar to the corresponding properties of Hsp90 isolated from other sources. In the presence of soluble carbodiimide and N-hydroxysuccinimide, rabbit liver Hsp90 can be cross-linked with calmodulin, troponin C, troponin I, and calponin. The data obtained indicate that Hsp90 may participate in the assembly of regulatory proteins of the actin filament.

Suppression of autocrine cell proliferation and tumorigenesis of human melanoma cells and fibroblast growth factor transformed fibroblasts by a kinase-deficient FGF receptor 1: evidence for the involvement of Src-family kinases

Basic Fibroblast Growth Factor (bFGF/FGF2) is thought to play a decisive role in malignant progression. Aberrant expression of bFGF causes constitutive autocrine activation of its cognate receptor and autonomous growth of human melanoma cells or bFGF transformed fibroblasts in culture. It remains to be determined, however, whether the endogenous bFGF confers growth advantage to tumors and what are the downstream targets of the activated FGF receptor critical for its transforming capacity. We therefore transfected metastatic melanoma cells and bFGF transformed mouse fibroblasts with a dominant-negative mutant of the murine FGF receptor 1 (fgfr1/flg), comprising the extracellular and transmembrane domains but lacking the intracellular kinase domain (dnflg). Reverse transcriptase-PCR, 125I-bFGF binding and affinity labeling analyses show that the truncated receptor is targeted to the membrane and is expressed at much higher levels than the endogenous receptor in all of the selected clones. Expression of the dnflg dramatically reduces the basal as well as bFGF induced growth of these cells in vitro and also suppresses their tumorigenic potential in nude mice. The expression of the dnflg does not significantly alter the general level of tyrosyl-phosphorylated proteins in the trunsduced melanoma cells. Rather, a major downstream affected target is a Src-family kinase, whose activity, determined by an in vitro immune kinase assay, is stimulated in normal melanocytes by exogenous bFGF, and is markedly reduced in the dnflg-expressing melanoma cells. The present study demonstrates that direct interference with the activity of FGF receptors has a deleterious effect on cell proliferation and survival in vitro and in vivo leading to the suppression of melanoma tumor progression possibly through the inactivation of a Src-family kinase.

Modification of protein surface hydrophobicity and methionine oxidation by oxidative systems

Aging and some pathological conditions are associated with the accumulation of altered (inactive or less active) forms of enzymes. It was suggested that these age-related alterations reflect spontaneous changes in protein conformation and/or posttranslational modifications (e.g., oxidation). Because changes in protein conformations are often associated with changes in surface hydrophobicity, we have examined the effects of aging and oxygen radical-dependent oxidation on the hydrophobicity of rat liver proteins. As a measure of hydrophobicity, the increase in fluorescence associated with the binding of 8-anilino-1-naphthalene-sulfonic acid to hydrophobic regions on the proteins was used. By this criterion, the hydrophobicity of liver proteins of 24-month-old rats was 15% greater than that of 2-month-old animals. Exposure of liver proteins to a metal-catalyzed oxidation system (ascorbate/Fe(II)/H2O2) or a peroxyl radical generating system, 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) led to increases of 2% or 30% in surface hydrophobicity, respectively. Treatment of liver proteins with the metal-catalyzed oxidation system led to a significant increase in reactive carbonyl content and to conversion of methionine residues to methionine sulfoxide residues. Treatment with AAPH led also to oxidation of methionine, tyrosine, and tryptophan residues and to the precipitation of some proteins. Dityrosine was detected in AAPH-treated protein, both the precipitate and supernatant fraction. The oxidation-dependent increase of hydrophobicity was correlated with an increase in the levels of methionine sulfoxide and dityrosine. These results suggest that oxidative modification of proteins may be responsible for the age-related increase of protein surface hydrophobicity in vivo, and that the oxidation of methionine by an oxidative system may be an important event for the change of protein conformation.

Estimation of optical constants of thin film by the use of artificial neural networks

A system for analyzing single-layer optical thin films has been formulated by the use of artificial neural networks. The training data sets stem from the computational results of the physical model of thin films, and they are used to train the artificial neural network, which, when done, can give values of film parameters in the millisecond time regime. The fast backpropagation algorithm is employed during training. The results of training are also given.

Matrix metalloproteinase 2 releases active soluble ectodomain of fibroblast growth factor receptor 1

Recent studies have demonstrated the existence of a soluble fibroblast growth factor (FGF) receptor type 1 (FGFR1) extracellular domain in the circulation and in vascular basement membranes. However, the process of FGFR1 ectodomain release from the plasma membrane is not known. Here we report that the 72-kDa gelatinase A (matrix metalloproteinase type 2, MMP2) can hydrolyze the Val368-Met369 peptide bond of the FGFR1 ectodomain, eight amino acids upstream of the transmembrane domain, thus releasing the entire extracellular domain. Similar results were obtained regardless of whether FGF was first bound to the receptor or not. The action of MMP2 abolished binding of FGF to an immobilized recombinant FGFR1 ectodomain fusion protein and to Chinese hamster ovary cells overexpressing FGFR1 The released recombinant FGFR1 ectodomain was able to bind FGF after MMP2 cleavage, suggesting that the cleaved soluble receptor maintained its FGF binding capacity. The activity of MMP2 could not be reproduced by the 92-kDa gelatinase B (MMP9) and was inhibited by tissue inhibitor of metalloproteinase type 2. These studies demonstrate that FGFR1 may be a specific target for MMP2 on the cell surface, yielding a soluble FGF receptor that may modulate the mitogenic and angiogenic activities of FGF.

Somatic c-KIT activating mutation in urticaria pigmentosa and aggressive mastocytosis: establishment of clonality in a human mast cell neoplasm

Mastocytosis is characterized by accumulations of mast cells in various organs (1). Most cases are indolent and confined to the skin, where discrete mast cell infiltrates are associated increased epidermal melanin, a clinical picture known as urticaria pigmentosa (UP). Other forms of mastocytosis combine UP with aggressive involvement of other organs or with haemotologic abnormalities (1-4). It is not known whether all forms of mastocytosis are true neoplasms or whether some might represent reactive hyperplasias (5-7). The c-KIT proto-oncogene encodes a type III receptor tyrosine kinase (KIT) that is critical to the development and survival of mast cells and melanocytes (8-11). The ligand for KIT (KL) can stimulate mast cell development, proliferation, and mediator release (9,12-17), as well as melanocyte proliferation and pigment production (18-20). To determine the role of c-KIT in the pathogenesis of mastocytosis, we examined tissue and cells isolated from a patient with UP and aggressive systemic mastocytosis with massive splenic involvement. We found a mutation that results in constitutive activation and expression of c-KIT in mast cells of both skin and spleen. This is the first in situ demonstration of an activation c-KIT mutation in neoplastic cells. It also demonstrates the clonal and neoplastic nature of this form of mastocytes.

The effects of vitamin C and urate on the oxidation kinetics of human low-density lipoprotein

Oxidative modification of human low-density lipoprotein (LDL) is believed to play an important role in atherogenesis. Vitamin C (ascorbate) and urate are major water-soluble plasma antioxidants in humans. Urate levels (300-395 microM) in human serum are considerably higher than ascorbate levels (30-50 microM). In this study, we compared the ability of urate to protect human LDL from in vitro oxidation with that of ascorbate. LDL was subjected to in vitro oxidation at 30 degrees C with an O2 saturated solution (0.15 M NaCl/0.25 mM EDTA) and 15 mM of a thermally labile water soluble azo-initiator (ABAP or azobis-2-amidinopropane HCl). In parallel experiments, 50 microM ascorbate or 50 microM urate were present in the oxidation buffer. The consumption of alpha-tocopherol, gamma-tocopherol, urate or ascorbate and the formation of lipid hydroperoxides were measured as a function of time in the in vitro oxidation system. The rate of lipid hydroperoxide formation was found to be significantly increased after the LDL tocopherols (alpha-plus gamma-tocopherol) were totally consumed, i.e., after the lag phase. Urate (50 microM) was more effective than ascorbate (50 microM) in extending the lag phase. Moreover, urate was consumed more slowly than ascorbate under identical oxidation conditions. Urate was not, however, as effective as ascorbate in preventing the formation of lipid hydroperoxides before the lag phase. An empirical mathematical model was also developed to describe the oxidation kinetics of LDL alpha- and gamma-tocopherol in the presence or absence of urate or ascorbate.

Calcium influx in induced differentiation of murine erythroleukemia cells

Murine erythroleukemia cells (MELC) have served as a model for examining the regulation of erythroid differentiation. However, the role of Ca2+ in the signal transduction pathways regulating differentiation remains unclear. To begin to address this uncertainty we have characterized the regulation of cytoplasmic Ca2+ and the possible role of calcium channels during induced differentiation in MELC. MELC can be induced to terminal differentiation using the polar/apolar compound hexamethylene bisacetamide (HMBA). We found that HMBA stimulated Ca2+ influx within 3 to 6 minutes and that Ca2+ entry was required but not sufficient for MELC growth and differentiation. Nifedipine (1 to 10 mumol/L), a calcium channel antagonist, blocked HMBA-induced Ca2+ influx and inhibited differentiation by approximately 60%. Depolarization of the MELC membrane did not induce Ca2+ influx and whole-cell patch-clamp recordings failed to detect a voltage-activated Ca2+ current, suggesting that MELC do not express detectable levels of a functional voltage-dependent calcium channel (VDCC). However, a cDNA probe encoding a portion of the alpha 1 subunit of the cardiac VDCC detected an approximately 8-kb mRNA on Northern blots of total MELC RNA. Taken together, these data show that Ca2+ influx is an early event associated with HMBA-induced differentiation in MELC, blockade of this calcium influx inhibits induced differentiation, and a voltage-insensitive dihydropyridine-sensitive calcium channel may be involved in Ca2+ influx in MELC.

[Effect of eleutherosides on ventricular late potential with coronary heart disease and myocarditis]

The article studied the curative effect of eleutherosides in patients with coronary heart disease and myocarditis whose ventricular late potential (VLP) were positive by means of control study. All the 57 patients were randomly divided into two groups. The 31 patients were classified as therapeutic group including male 25 and female 6, the ages ranged from 18-65 years old (mean 51.8). The other 26 patients were defined as control group including male 21 and female 5, the ages ranged from 16-63 years old (mean 50.8). The therapeutic group was treated with injectio acanthopanacis senticosi 40 ml dissolved in 5% dextrose injection 300 ml by intravenous drop once daily. The control group was given insulin injection 12 u and potassium chloride injection 1 g dissolved in 10% dextrose injection 500 ml also by intravenous drop once daily. Both courses of treatment were 15 days. The rates of changing positive VLP into negative in two groups were 74.29% vs 34.6% (P less than 0.005). The results proved that eleutherosides is an effective drug to patients with positive VLP.

[A study of the effect of patient load and diseases upon resident training in a family medicine clinic]

Patient appointments and scheduling of patients and physicians are the first step in family medicine practice. The goals of outpatient services are to train the family physicians, to provide comprehensive and continuing health care for the family and its members. We evaluated the effect of the appointment system upon residents' training in a family medicine clinic of the Kaohsiung Medical College Hospital. The results were as follows: during the period between Aug. 1985 and Nov. 1986, a total of 2,220 patients and 5,891 out-patient encounters was recorded in this module. The subject age was mostly in the range of 16-64 years for all trainees. The distribution of the chronic diseases was relatively even for all except two trainees. For 4 residents, there were 40-60% more than the ideal patient numbers per session. This abnormal situation interferes with the normal functioning of family medicine clinics. The provocative results of this study suggest at least two important avenues for improvement. The first is to modify the appointment system. The second is to schedule the ideal amount of patients and kinds of diseases in order to provide comprehensive and continuous care for the family and its members.

Long-term follow-up of 344 Shanghai psoriatics

344 patients with psoriasis vulgaris treated in Huashan Hospital, Shanghai were followed up for 7-30 years. 13% of them developed arthralgia and 2% had joint deformities. One patient developed erythroderma due to dexamethasone medication. Internal malignancy occurred in 2 patients (0.58%). The severity of the course of the disease was neither influenced by family history nor alcoholism, but was markedly influenced by the duration of illness and administration of anti-neoplastic drugs.