Ureaplasma urealyticum (UU) is one of the most commonly occurring pathogens associated with genital tract infections in infertile males, but the impact of seminal UU infection in semen on intrauterine insemination (IUI) outcomes is poorly understood. We collected data from 245 infertile couples who underwent IUI at The First Affiliated Hospital of USTC (Hefei, China) between January 2021 and January 2023. The subjects were classified into two groups according to their UU infection status: the UU-positive group and the UU-negative group. We compared semen parameters, pregnancy outcomes, and neonatal birth outcomes to investigate the impact of UU infection on IUI outcomes. There were no significantly statistical differences in various semen parameters, including semen volume, sperm concentration, total and progressive motility, sperm morphology, leukocyte count, the presence of anti-sperm antibody, and sperm DNA fragmentation index (DFI), between the UU-positive and UU-negative groups of male infertile patients (all P > 0.05). However, the high DNA stainability (HDS) status of sperm differed between the UU-positive and UU-negative groups, suggesting that seminal UU infection may affect sperm nuclear maturation ( P = 0.04). Additionally, there were no significant differences in pregnancy or neonatal birth outcomes between the two groups (all P > 0.05). These results suggest that IUI remains a viable and cost-effective option for infertile couples with UU infection who are facing infertility issues.
Humans ; Male ; Ureaplasma Infections/complications* ; Female ; Infertility, Male/therapy* ; Ureaplasma urealyticum/isolation & purification* ; Pregnancy ; Adult ; Pregnancy Outcome ; Semen Analysis ; Insemination, Artificial ; Semen/microbiology* ; China

OBJECTIVE: To investigate the short-and med-term clinical efficacy of unicompartmental knee arthroplasty(UKA)for the treatment of medial knee osteoarthritis (OA) in elderly patients with anterior cruciate ligament deficiency(ACLD). METHODS: A retrospective analysis was conducted on 31 patients aged over 75 years old with primary medial knee OA and ACLD who underwent UKA between January 2018 and December 2022. The cohort included 12 males and 19 females, aged from 75 to 91 years with an average age of (79.56±4.54) years, with 13 left knee, 16 right knee, and 2 bilateral knees. Clinical outcomes were assessed preoperatively and at final follow-up using the visual analogue scale (VAS), Hospital for Special Surgery(HSS) score, range of motion (ROM), hip-knee-ankle angle (HKA), and tibial component posterior slope angle (TCPSA). Complications such as infection, prosthesis wear, prosthesis loosening, and dislocation were also recorded. RESULTS: All 31 patients were followed up from 12 to 63 months with an average of (28.34±10.56) months. The average postoperative TCPSA was (4.83±1.31)° ranged from 2.5° to 6.8°. At the final follow-up, there was significant improvement in VAS (3.24±0.53) vs. (6.59±0.69), HSS score (85.19±4.45) vs. (64.38±5.94), ROM (118.83±5.38)° vs. (98.85±4.08)°, and HKA (176.83±5.16)° vs. (169.57±6.28)° compared to preoperative values (P<0.05). No cases of infection, prosthesis loosening, or dislocation were reported. CONCLUSION UKA provides favorable short-and mid-term outcomes for elderly patients with medial knee OA and ACLD . However, long-term clinical efficacy needs further investigation through extended follow-up.
Humans ; Male ; Female ; Arthroplasty, Replacement, Knee/methods* ; Aged ; Osteoarthritis, Knee/physiopathology* ; Retrospective Studies ; Aged, 80 and over ; Range of Motion, Articular ; Anterior Cruciate Ligament Injuries/surgery*

Objective:To investigate the differences in clinical outcomes of septic children with varying serum zinc levels,and to analyze the relationship between reduced serum zinc levels and organ dysfunction as well as 28-day mortality in septic children.Methods:This study conducted a retrospective analysis of clinical data from pediatric patients diagnosed with sepsis or septic shock in the Department of critical care medicine of the children's Hospital of Soochow University between January 2017 and December 2022.Clinical characteristics,organ dysfunction,and prognosis were compared between two groups:children with low serum zinc levels and those with normal zinc levels.Results:The serum zinc level of septic children within 24 hours of admission was 9.60(5.52,13.80)μmol/L,with 50.54%(94/186)of the children exhibiting low serum zinc levels(<10.07 μmol/L).Compared to the normal serum zinc group,the low serum zinc group had a significantly lower Pediatric Critical Illness Score(PCIS)[(78.71±9.35)vs.(85.12±8.51),P=0.005]and higher 28-day mortality(46.80%vs.14.13%,P<0.001).The low serum zinc group also had a higher proportion of invasive mechanical ventilation(64.89%vs.47.82%,P=0.019),renal replacement therapy(15.59%vs.3.26%,P=0.003),and use of vasoactive drugs(56.38%vs.30.43%,P<0.001).The rate of underlying conditions in the low serum zinc group was significantly higher than that in the normal serum zinc group(57.44%vs.36.95%,P=0.005).Additionally,the low serum zinc group had a higher incidence of disseminated intravascular coagulation(DIC),respiratory failure,acute kidney injury,shock,and multiple organ dysfunction syndrome(MODS)compared to the normal serum zinc group(P<0.05).Serum zinc levels had predictive value for 28-day mortality in septic children(AUC=0.813;95%CI:0.725～0.902;P<0.001).A serum zinc level of less than 6.950 μmol/L predicted the death of septic children with a sensitivity of 0.618 and a specificity of 0.902.Conclusion:Sepsis in children is commonly associated with low serum zinc levels,especially in those with underlying conditions such as hematologic and oncologic disorders.Sepsis patients hypozincemia with a higher incidence of DIC,respiratory failure,acute kidney injury,shock,and MODS.A serum zinc level below 6.95 μmol/L serves as a significant predictor of 28-day mortality in children with severe sepsis.

ObjectiveAcute myocardial infarction (AMI) is a highly prevalent and deadly disease globally, with its incidence continuing to rise in recent years. Timely reperfusion therapy is crucial for improving the prognosis of AMI patients. However, myocardial reperfusion can lead to irreversible myocardial ischemia/reperfusion (MI/R) injury, which is associated with adverse cardiovascular outcomes following AMI. Studies have shown that microRNAs (miRNAs) are abnormally expressed during MI/R injury and play an important role in the fate of cardiomyocytes. Effective preventive and therapeutic strategies against MI/R injury remain lacking in clinical practice, necessitating elucidation of the molecular mechanisms underlying MI/R onset and progression. This study investigated the role of microRNA-878 (miR-878) in the regulation of mitochondria-mediated apoptosis in MI/R injury. MethodsThe H9c2 cells were flushed with a gas mixture containing 1% O₂, 5% CO₂ and 94% N₂ for 3 h. Then the cells were incubated in complete culture medium under 5% CO₂ and 95% air for 6 h to mimic in vivo hypoxia/reoxygenation (H/R) injury. Cell viability were detected by CCK-8 assay. The concentrations of lactate dehydrogenase (LDH) were then measured.The level of apoptosis was analyzed by flow cytometry. The morphology of mitochondria was analyzed by immunofluorescence and laser confocal microscopy. The levels of mitochondrial reactive oxygen species (mtROS) were detected by immunofluorescence. Dual luciferase reporter gene assay was used to study the binding site of miR-878 and Pim1. RNA immunoprecipitation (RIP) assay was used to verify the binding relationship between miR-878 and Pim1. The gene expression levels were detected by real-time fluorescent quantitative PCR (RT-qPCR) and Western blot. ResultsThe study found that compared with the control group, the expression of miR-878 in H/R-treated H9c2 cells was significantly increased ((1.00±0.25) vs (9.70±2.63), P<0.01). In H/R-induced cells, transfection of miR-878 inhibitor significantly increased cell viability ((46.67±3.00) vs (74.62±4.08), P<0.000 1), and decreased LDH release ((358.58±41.71) vs (179.09±15.59), P<0.000 1) and cell apoptosis rate ((43.41±0.72) vs (27.42±4.48), P<0.01). At the same time, downregulation of miR-878 expression significantly inhibited DRP1-mediated mitochondrial overdivision and mtROS production ((6.60±0.57) vs (4.32±0.91), P<0.000 1). The mechanism study showed that miR-878 could target and bind Pim1 and inhibit the expression level of Pim1 ((1.00±0.13) vs (0.38±0.03), P<0.01). Rescue experiments confirmed that down-regulation of Pim1 expression significantly reversed the anti-injury effect of miR-878 inhibitor in H9c2 cells (P<0.01), promoted mitochondrial overdivision and mtROS production ((1.00±0.12) vs (2.41±0.12), P<0.01), and decreased the expression level of p-DRP1 ((1.00±0.15) vs (0.59±0.06), P<0.05). ConclusionThe present study demonstrates that miR-878 expression is upregulated in H9c2 cardiomyocytes subjected to H/R injury. Inhibition of miR-878 expression alleviates H/R-induced cardiomyocyte damage. Notably, downregulation of miR-878 significantly inhibits DRP1-mediated mitochondrial fission and mitigates mtROS production. Mechanistically, miR-878 targets and binds to the 3'-UTR of the Pim1 gene, thereby suppressing Pim1 protein expression. Collectively, these findings suggest that under H/R conditions, miR-878 promotes excessive mitochondrial fragmentation through DRP1 activation by targeting Pim1, ultimately contributing to cardiomyocyte injury. Modulation of the miR-878/Pim1 axis may represent a potential therapeutic strategy for mitigating MI/R-induced cardiac damage.

Objective To observe the therapeutic effect and mechanism of Baoyuan Decoction for chronic heart failure model rat.Methods SD rats were randomly divided into blank group,model group,Baoyuan Decoction group,Captopril group,Baoyuan Decoction+CCT020312[protein kinase R-like endoplasmic reticulum kinase(PERK)activator]group,15 rats in each group.Except for the blank group,the rats in the other groups were induced by Adriamycin to construct a chronic heart failure model.After corresponding drug intervention,cardiac function indexes[left ventricular end-diastolic diameter(LVEDD),left ventricular ejection fraction(LVEF),left ventricular fractional shortening(LVFS),brain natriuretic peptide(BNP),cardiac troponin I(cTnI)],inflammation-related factors[tumor necrosis factor α(TNF-α),interleukin 1β(IL-1β)],oxidative stress factors[malondialdehyde(MDA),superoxide dismutase(SOD)]were detected in each group.Changes in apoptosis-related indicators[B-cell lymphoma 2(Bcl-2),B-cell lymphoma 2-associated X protein(Bax),Caspase-3]and PERK/transcription activator 4(ATF4)signaling pathway-related proteins glucose-regulated protein 78(GRP78),PERK,ATF4,C/EBP homologous protein(CHOP)levels.Results Compared with the blank group,LVEDD,BNP,cTnI,TNF-α,IL-1β,MDA levels,protein expression levels of Bax,Caspase-3,GRP78,PERK,ATF4,CHOP in the model group were significantly increased,LVEF,LVFS,SOD levels and Bcl-2 protein expression level were significantly decreased(all P＜0.05).Compared with the model group and Baoyuan Decoction+CCT020312 group,LVEDD,BNP,cTnI,TNF-α,IL-1β,MDA levels,protein expression levels of Bax,Caspase-3,GRP78,PERK,ATF4,CHOP in Baoyuan Decoction group and Captopril group were significantly decreased,LVEF,LVFS,SOD levels and Bcl-2 protein expression level were significantly increased(all P＜0.05).Compared with the Captopril group,there was no significant change in the above indexes(except CHOP protein expression level)in the Baoyuan Decoction group(P＞0.05).Conclusion Baoyuan Decoction can delay the progression of chronic heart failure rats,and its mechanism may be related to inhibiting the PERK/ATF4 signaling pathway to alleviate cardiomyocyte apoptosis,further reducing the degree of inflammatory response and oxidative stress,thereby promoting the repair of cardiac function and myocardial injury.

Purpose::To explore the effect of green channel for stroke patients on the treatment of severe aneurysmal subarachnoid hemorrhage.Methods::This is a retrospective case-control study. The clinical data of patients with severe aneurysmal subarachnoid hemorrhage admitted to the emergency department of our hospital from January 2015 to June 2022 were retrospectively analyzed. Patients diagnosed with subarachnoid hemorrhage, confirmed intracranial aneurysm by preoperative CT angiography or digital subtraction, graded Hunt-Hess grade III, IV, and V, < 72 h from the onset to the time of consultation received surgical treatment in our hospital were included in this study. Patients with serious underlying diseases, such as heart, liver, kidney diseases, or malignant tumors, traumatic subarachnoid hemorrhage, previous history of cerebral hemorrhage, and incomplete data were excluded. The control group included patients with severe aneurysmal subarachnoid hemorrhage admitted from January 2015 to December 2018 before the establishment of the green channel for stroke patients, and the observation group included patients with severe aneurysmal subarachnoid hemorrhage admitted from January 2019 to June 2022 after the establishment of the green channel. The control group received routine treatment in the emergency department; the observation group received improved treatment of green channel for stroke patients. Gender, age, Hunt-Hess grade on admission, modified Rankin scale (mRS) on admission, aneurysm location, aneurysm size and whether accompanied by intracerebral hemorrhage, the time from onset to emergency department, the time from emergency department to vascular diagnostic examination, the time from onset to surgery, the time from emergency department to surgery, the time from hospital admission to surgery, length of hospital stay, complications, treatment effect were analyzed and compared between the 2 groups. SPSS 23.0 software was utilized to conduct comparisons between the 2 groups. The t-test, Chi-square test, or Mann-Whitney U test was chosen based on the data type. Statistical significance was established when p < 0.05. Results::A total of 71 patients were included in this study, of whom 37 were in the control group and 34 were in the observation group. There were no statistical differences in age, gender, Hunt-Hess grade, mRS scores, aneurysm location, aneurysm size, intracerebral hemorrhage, the time from onset to emergency department, length of hospital stay, complications between the observation group and the control group (all p > 0.05). The time (min) from visit to vascular diagnostic test (60.50 vs. 120.00, p =0.027), the time (min) from onset to surgery (1792.00 vs. 2868.00, p =0.023), the time (min) from emergency department to surgery (1568.50 vs. 2778.00, p =0.016), the time (min) from hospital admission to surgery (1188.50 vs. 2708.00, p =0.043), all of them were shorter in the observation group than those in the control group. The relative values of admission and 7-day postoperative mRS scores and the relative values of admission and discharge mRS scores ≥ 2 were used as the criteria for determining better efficacy, and the treatment effect was better than that in the control group, and the differences were statistically significant (admission to 7 days postoperative mRS score ≥ 2, 17 (50.0 %) vs. 8 (21.6 %), p =0.012; admission to discharge mRS score ≥ 2, 19 (55.9 %) vs. 11 (29.7 %), p =0.026). Conclusion::The green channel for stroke patients with severe aneurysmal subarachnoid hemorrhage can effectively shorten the time from arrival at the emergency department to vascular diagnostic examination and the time from the emergency department to surgery, and achieve a better therapeutic effect, which is worth popularizing and applying.

Objective To explore the treatment effects and mechanism of Fangji Huangqi Xiaozhong Prescription in metabolic syndrome phenotype osteoarthritis(MS-OA)based on PPARγ/NF-κB signaling pathway.Methods SD rats were randomly divided into sham-operation group,OA group,MS-OA group,Western medicine group,and TCM high-and low-dasage groups.The modified Hulth method was used to make the OA model,and OA model was added with high-carbohydrate high-fat diet to make the MS-OA model.TCM high-and low-dosage groups were given 15.12,7.56 g/kg Fangji Huangqi Xiaozhong Prescription for gavage.The Western medicine group was given 16.2 mg/kg of losoprofen sodium by gavage,while the other groups were given physiological saline by gavage once a day for 6 consecutive weeks.Rat body mass was measured,biochemical detection of blood lipids and blood glucose was conducted,ELISA was used to detect the contents of serum TNF-α,IL-1β,IL-10 and leptin,morphological changes in cartilage tissue were observed using safranin O-fixed green and HE staining,immunohistochemical staining was used to detect expressions of Acan,ColⅩ,MMP13,TNF-α,IL-1β and PPARγ in cartilage tissue,Western blot was used to detected the expression of PPARγ,NF-κBp65 and p-NF-κBp65 protein in cartilage tissue.Results Compared with the sham-operation group,body mass and serum TC,TG,LDL-C,TNF-α,IL-1β and leptin of MS-OA group increased significantly(P<0.01),the contents of HDL-C and IL-10 decreased(P<0.01),cartilage tissue degeneration was significant,and the Mankin score increased(P<0.01),the expression of ColⅩ,MMP13,TNF-α,IL-1β,p-NF-κBp65 protein increased(P<0.05,P<0.01),and the expression of Acan and PPARγ protein decreased(P<0.01).Compared with the MS-OA group,the contents of serum TC,TG,LDL-C,TNF-α and leptin decreased in TCM high-dosage group(P<0.05,P<0.01),the content of IL-10 increased(P<0.05),the pathological damage of cartilage tissue improved,the Mankin score decreased(P<0.01),the expressions of ColⅩ,MMP13,TNF-α,IL-1β and p-NF-κBp65 protein in cartilage tissue decreased(P<0.05,P<0.01),and the protein expressions of Acan and PPARγ protein increased(P<0.01,P<0.05).Conclusion Fangji Huangqi Xiaozhong Prescription can improve lipid metabolism disorder,improve intra-articular inflammatory environment,balance cartilage metabolism,and delay cartilage degeneration in MS-OA rats.Its mechanism may be related to the regulation of PPARγ/NF-κB signaling pathway.

Aim To dynamically characterize neuronal damage in the cortex and hippocampus of mice follow-ing acute cerebral ischemia/reperfusion(I/R).Meth-ods Male C57BL/6J mice weighing 25-28 g under-went middle cerebral artery occlusion using the fila-ment method,followed by 1 hour of reperfusion to es-tablish the acute cerebral I/R injury mouse model.The experiment comprised a sham surgery group,I/R-6 h group,I/R-24 h group,and I/R-72 h group.Longa neurological function score was used to assess the neu-rological function.Triphenyltetrazolium chloride(TTC)staining was conducted to detect cerebral in-farct volume.Hematoxylin and eosin(HE)staining was utilized to observe brain tissue pathological dam-age.Nissl staining was performed to evaluate neuronal damage.Immunofluorescence histochemistry staining was employed to assess the activation of astrocytes and microglia,as well as neuronal loss.Transmission elec-tron microscopy was used to examine mitochondrial damage in hippocampal neurons.Western blot analysis was conducted to detect the expression levels of mito-chondrial fission-fusion-related proteins p-Drp1/Drp1,Mff,Fis1,and OPA1.Results With prolonged cere-bral I/R time,neurological functional impairment,cerebral infarct volume,neuronal damage in the cortex and hippocampus,glial cell activation,neuronal loss,and mitochondrial damage gradually worsened in mice.The expression of mitochondrial fission-related proteins increased gradually,while the expression of mitochon-drial fusion-related proteins decreased gradually.Con-clusions Neuronal pathological damage,such as glial cell activation,neuronal loss,and mitochondrial dam-age,is gradually aggravated with prolonged cerebral I/R time,which may be associated with mitochondrial dynamics imbalance.

Gongju(Chrysanthemum morifolium) is one of the five major medicinal Chrysanthemum varieties included in the Chinese Pharmacopoeia. In recent years, its cultivation areas have changed significantly, resulting in mixed quality of the medicinal herbs. In this study, Gongju cultivated in Anhui, Yunnan, Chongqing, and other places were selected as research objects. Hyperspectral data were collected in the visible-near-infrared(VNIR) and short-wave infrared(SWIR) bands using different modes, such as corolla facing up(A) and flower base facing up(B). After pre-processing the hyperspectral data using five methods, including multiplicative scatter correction(MSC), Savitzky-Golay smoothing(SG), first derivative(D1), second derivative(D2), and standard normal variate(SNV), partial least squares discriminant analysis(PLSDA), random forest(RF), and support vector machine(SVM) were used to establish origin identification models of Gongju at the two geographical scales of the province and the city-county in Anhui province. The accuracy of the prediction results was used as an evaluation index to select the optimal models, and the classification performance of the models was evaluated by confusion matrix. The results showed that the flower base facing up(B) collection model combined with second derivative pretreatment and RF method was the best model for both geographical scale identification models. The modeling effect of the full-band(VNIR + SWIR) was slightly better than that of the single band, with the accuracy of the prediction set in the province and city-county regions reaching 99.69% and 99.40%, respectively. The competitive adaptive reweighted sampling algorithm(CARS), successive projections algorithm(SPA), and variable iterative space shrinkage approach(VISSA) were further used to screen the feature wavelength modeling. The number of feature wavelengths screened by CARS was fewer, and the prediction set accuracy of the two geographical scales models after optimization could reach 99.56% and 98.65%, which was basically comparable to the full-band model. However, the removal of redundant variables could greatly reduce the complexity of the model. The hyperspectral technology combined with the chemometrics model established in this study can achieve the origin identification of Gongju at different geographical scales, providing a theoretical basis and technical reference for the construction of a rapid detection system for Gongju origin and the development of exclusive miniaturized instrumentation and equipment systems.
Chrysanthemum/growth & development* ; China ; Support Vector Machine ; Geography ; Discriminant Analysis ; Spectroscopy, Near-Infrared/methods* ; Spectrum Analysis/methods* ; Drugs, Chinese Herbal/analysis* ; Least-Squares Analysis

Objective: To analyze the prevalence and the risk factors of fungal sepsis in 25 neonatal intensive care units (NICU) among preterm infants in China, and to provide a basis for preventive strategies of fungal sepsis. Methods: This was a second-analysis of the data from the "reduction of infection in neonatal intensive care units using the evidence-based practice for improving quality" study. The current status of fungal sepsis of the 24 731 preterm infants with the gestational age of <34⁺⁰ weeks, who were admitted to 25 participating NICU within 7 days of birth between May 2015 and April 2018 were retrospectively analyzed. These preterm infants were divided into the fungal sepsis group and the without fungal sepsis group according to whether they developed fungal sepsis to analyze the incidences and the microbiology of fungal sepsis. Chi-square test was used to compare the incidences of fungal sepsis in preterm infants with different gestational ages and birth weights and in different NICU. Multivariate Logistic regression analysis was used to study the outcomes of preterm infants with fungal sepsis, which were further compared with those of preterm infants without fungal sepsis. The 144 preterm infants in the fungal sepsis group were matched with 288 preterm infants in the non-fungal sepsis group by propensity score-matched method. Univariate and multivariate Logistic regression analysis were used to analyze the risk factors of fungal sepsis. Results: In all, 166 (0.7%) of the 24 731 preterm infants developed fungal sepsis, with the gestational age of (29.7±2.0) weeks and the birth weight of (1 300±293) g. The incidence of fungal sepsis increased with decreasing gestational age and birth weight (both P<0.001). The preterm infants with gestational age of <32 weeks accounted for 87.3% (145/166). The incidence of fungal sepsis was 1.0% (117/11 438) in very preterm infants and 2.0% (28/1 401) in extremely preterm infants, and was 1.3% (103/8 060) in very low birth weight infants and 1.7% (21/1 211) in extremely low birth weight infants, respectively. There was no fungal sepsis in 3 NICU, and the incidences in the other 22 NICU ranged from 0.7% (10/1 397) to 2.9% (21/724), with significant statistical difference (P<0.001). The pathogens were mainly Candida (150/166, 90.4%), including 59 cases of Candida albicans and 91 cases of non-Candida albicans, of which Candida parapsilosis was the most common (41 cases). Fungal sepsis was independently associated with increased risk of moderate to severe bronchopulmonary dysplasia (BPD) (adjusted OR 1.52, 95%CI 1.04-2.22, P=0.030) and severe retinopathy of prematurity (ROP) (adjusted OR 2.55, 95%CI 1.12-5.80, P=0.025). Previous broad spectrum antibiotics exposure (adjusted OR=2.50, 95%CI 1.50-4.17, P<0.001), prolonged use of central line (adjusted OR=1.05, 95%CI 1.03-1.08, P<0.001) and previous total parenteral nutrition (TPN) duration (adjusted OR=1.04, 95%CI 1.02-1.06, P<0.001) were all independently associated with increasing risk of fungal sepsis. Conclusions: Candida albicans and Candida parapsilosis are the main pathogens of fungal sepsis among preterm infants in Chinese NICU. Preterm infants with fungal sepsis are at increased risk of moderate to severe BPD and severe ROP. Previous broad spectrum antibiotics exposure, prolonged use of central line and prolonged duration of TPN will increase the risk of fungal sepsis. Ongoing initiatives are needed to reduce fungal sepsis based on these risk factors.
Infant ; Infant, Newborn ; Humans ; Birth Weight ; Intensive Care Units, Neonatal ; Retrospective Studies ; Tertiary Care Centers ; Infant, Extremely Low Birth Weight ; Gestational Age ; Infant, Extremely Premature ; Sepsis/epidemiology* ; Retinopathy of Prematurity/epidemiology* ; Bronchopulmonary Dysplasia/epidemiology*