Objective:To develop a novel, flexible, dual-arm, master-slave digestive endoscopic minimally invasive surgical robot system named dual-arm robotic endoscopic assistant for minimally invasive surgery (DREAMS) and to evaluate its feasibility for endoscopic submucosal dissection (ESD) by using ex vivo porcine stomachs.Methods:A novel endoscopic robot (DREAMS) system was developed which was composed of a flexible two-channel endoscope, two flexible robotic manipulators, a master controller, a robotic arm, and a control system. A total of 10 artificial round-like lesions with diameters ranging from 15 to 25 mm were created (5 in gastric antrum and 5 in gastric body) by using fresh peeled stomach of healthy pigs as the model. Submucosal dissection was performed with the assistance of the DREAMS system by two operators. The main outcome was submucosal dissection speed, and the secondary outcomes included muscular injury rate, perforation rate, and grasping efficiency of the robot.Results:All 10 lesions were successfully dissected en bloc by using the DREAMS system. The diameter of the artificial lesions was 22.34±2.39 mm, dissection time was 15.00±8.90 min, submucosal dissection speed was 141.79±79.12 mm 2/min, and the number of tractions required by each ESD was 4.2 times. Muscular injury occurred in 4/10 cases of ESD. No perforation occurred. Conclusion:The initial animal experiment shows the DREAMS system is safe and effective.

Objective:To examine treatment outcomes of breast phyllodes tumors and the prognosis factors of local recurrence.Methods:This retrospective cohort study included 276 patients who underwent surgical resection at Breast Center, Peking University People′s Hospital from January 2011 to December 2019. Tumor subtype and histopathological features were determined from pathology reports, and the deadline of follow-up was September 30 th, 2020. All 276 patients underwent open surgery, including 17 patients of mastectomy, and 259 patients of lumpectomy. The enrolled patients were all female, with age of (41.5±11.3) years (rang: 11 to 76 years), and tumor diameter of 35(28) mm ( M( Q R)). The Kaplan-Meier method and Log-rank test were used for survival analysis. The multivariate analysis was implemented using the Cox proportional hazard model. Results:According the pathologic test, there were 191 patients of benign phyllodes tumor, 67 patients of borderline tumor and 18 patients of malignant tumor. There were 249 patients with a follow-up of more than 6 months, and 14.1% (35/249) had local recurrence. The time-to-recurrence was (28.6±22.2) months (range: 2 to 96 months), (29.1±18.1) months (range: 2 to 80 months), (32.1±30.1) months (range: 5 to 96 months) and (12.0±6.9) months (range: 8 to 20 months) for benign, borderline and malignant phyllodes tumors. Tumor diameter (≥100 mm vs.<50 mm, HR=3.968, 95%CI: 1.550 to 10.158, P=0.004) and malignant heterologous element (yes vs. no, HR=26.933, 95%CI: 3.105 to 233.600, P=0.003) were prognosis factors of local recurrence. One death from malignant phyllodes occurred after distant metastasis. The 3-year disease-free survival rates of benign, borderline and malignant phyllodes tumor were 88.2%, 81.7% and 81.4% ( P=0.300). Conclusion:Phyllodes tumors have a considerable local recurrence rate, which may be associated with tumor diameter and malignant heterologous element.

Objective:To examine treatment outcomes of breast phyllodes tumors and the prognosis factors of local recurrence.Methods:This retrospective cohort study included 276 patients who underwent surgical resection at Breast Center, Peking University People′s Hospital from January 2011 to December 2019. Tumor subtype and histopathological features were determined from pathology reports, and the deadline of follow-up was September 30 th, 2020. All 276 patients underwent open surgery, including 17 patients of mastectomy, and 259 patients of lumpectomy. The enrolled patients were all female, with age of (41.5±11.3) years (rang: 11 to 76 years), and tumor diameter of 35(28) mm ( M( Q R)). The Kaplan-Meier method and Log-rank test were used for survival analysis. The multivariate analysis was implemented using the Cox proportional hazard model. Results:According the pathologic test, there were 191 patients of benign phyllodes tumor, 67 patients of borderline tumor and 18 patients of malignant tumor. There were 249 patients with a follow-up of more than 6 months, and 14.1% (35/249) had local recurrence. The time-to-recurrence was (28.6±22.2) months (range: 2 to 96 months), (29.1±18.1) months (range: 2 to 80 months), (32.1±30.1) months (range: 5 to 96 months) and (12.0±6.9) months (range: 8 to 20 months) for benign, borderline and malignant phyllodes tumors. Tumor diameter (≥100 mm vs.<50 mm, HR=3.968, 95%CI: 1.550 to 10.158, P=0.004) and malignant heterologous element (yes vs. no, HR=26.933, 95%CI: 3.105 to 233.600, P=0.003) were prognosis factors of local recurrence. One death from malignant phyllodes occurred after distant metastasis. The 3-year disease-free survival rates of benign, borderline and malignant phyllodes tumor were 88.2%, 81.7% and 81.4% ( P=0.300). Conclusion:Phyllodes tumors have a considerable local recurrence rate, which may be associated with tumor diameter and malignant heterologous element.

OBJECTIVE: To analyze the clinical characteristics and treatment outcomes of the first episode of peritoneal dialysis-associated peritonitis (PDAP) in patients receiving long-term peritoneal dialysis. METHODS: The clinical data of patients with the first episode of PDAP in 4 general hospitals in Jilin Province from 2013 to 2019 were collected retrospectively. According to the duration of dialysis, the patients were divided into long-term (≥36 months) and short-term (< 36 months) dialysis groups for comparison of the clinical data, treatment outcomes and long-term prognostic events. RESULTS: A total of 625 patients with PDAP were enrolled, including 93 on long-term and 532 on short-term dialysis. Compared with those on short-term dialysis, the patients on long-term dialysis had significantly higher hemoglobin levels and lower glomerular filtration rates when the first episode of PDAP occurred ( CONCLUSIONS Compared with those on short-term dialysis, patients on long-term dialysis are prone to gram-negative bacterial infection when the first episode of PDAP occurs with worse treatment outcomes but similar long-term outcomes. Long-term dialysis is an independent risk factor of extubation and treatment failure for the first episode of PDAP, and fungal and mixed bacterial infections are independent risk factors for treatment failure of the first PDAP in patients with long-term dialysis.
Humans ; Kidney Failure, Chronic/therapy* ; Peritoneal Dialysis/adverse effects* ; Peritonitis/etiology* ; Retrospective Studies ; Treatment Outcome

Objective:Surgical site infection (SSI) is the most common infectious complication after emergency abdominal surgery (EAS). To a large extent, most SSI can be prevented, but there are few relevant studies in China. This study mainly investigated the current situation of SSI occurrence after EAS in China, and further explored risk factors for SSI occurrence.Methods:Multi-center cross-sectional study was conducted. Clinical data of patients undergoing EAS in 33 hospitals across China between May 1, 2019 and June 7, 2019 were prospectively collected, including perioperative data and microbial culture results from infected incisions. The primary outcome was the incidence of SSI after EAS, while the secondary outcomes were postoperative hospital stay, ICU occupancy rate, length of ICU stay, hospitalization cost, and mortality within postoperative 30 days. Univariate and multivariate logistic regression models were used to analyze the risk factors of SSI after EAS.Results:A total of 660 EAS patients aged (47.9±18.3) years were enrolled in this study, including 56.5% of males (373/660). Forty-nine (7.4%) patients developed postoperative SSI. The main pathogen of SSI was Escherichia coli [culture positive rate was 32.7% (16/49)]. As compared to patients without SSI, those with SSI were more likely to be older (median 56 years vs. 46 years, U=19 973.5, P<0.001), male [71.4% (35/49) vs. 56.1% (343/611), χ 2=4.334, P=0.037] and diabetes [14.3% (7/49) vs. 5.1% (31/611), χ 2=5.498, P=0.015]; with-lower preoperative hemoglobin (median: 122.0 g/L vs. 143.5 g/L, U=11 471.5, P=0.006) and albumin (median: 35.5 g/L vs. 40.8 g/L, U=9452.0, P<0.001), with higher blood glucose (median: 6.9 mmol/L vs. 6.0 mmol/L, U=17 754.5, P<0.001); with intestinal obstruction [32.7% (16/49) vs. 9.2% (56/611), χ 2=25.749, P<0.001], with ASA score 3-4 [42.9% (21/49) vs. 13.9% (85/611), χ 2=25.563, P<0.001] and with high surgical risk [49.0% (24/49) vs. 7.0% (43/611), χ 2=105.301, P<0.001]. The main operative procedure resulting in SSI was laparotomy [81.6%(40/49) vs. 35.7%(218/611), χ 2=40.232, P<0.001]. Patients with SSI experienced significantly longer operation time (median: 150 minutes vs. 75 minutes, U=25 183.5, P<0.001). In terms of clinical outcome, higher ICU occupancy rate [51.0% (25/49) vs. 19.5% (119/611), χ 2=26.461, P<0.001], more hospitalization costs (median: 44 000 yuan vs. 15 000 yuan, U=24 660.0, P<0.001), longer postoperative hospital stay (median: 10 days vs. 5 days, U=23 100.0, P<0.001) and longer ICU occupancy time (median: 0 days vs. 0 days, U=19 541.5, P<0.001) were found in the SSI group. Multivariate logistic regression analysis showed that the elderly (OR=3.253, 95% CI: 1.178-8.985, P=0.023), colorectal surgery (OR=9.156, 95% CI: 3.655-22.937, P<0.001) and longer operation time (OR=15.912, 95% CI:6.858-36.916, P<0.001) were independent risk factors of SSI, while the laparoscopic surgery (OR=0.288, 95% CI: 0.119-0.694, P=0.006) was an independent protective factor for SSI. Conclusions:For patients undergoing EAS, attention should be paid to middle-aged and elderly patients and those of colorectal surgery. Laparoscopic surgery should be adopted when feasible and the operation time should be minimized, so as to reduce the incidence of SSI and to reduce the burden on patients and medical institutions.

Objective:Surgical site infection (SSI) is the most common infectious complication after emergency abdominal surgery (EAS). To a large extent, most SSI can be prevented, but there are few relevant studies in China. This study mainly investigated the current situation of SSI occurrence after EAS in China, and further explored risk factors for SSI occurrence.Methods:Multi-center cross-sectional study was conducted. Clinical data of patients undergoing EAS in 33 hospitals across China between May 1, 2019 and June 7, 2019 were prospectively collected, including perioperative data and microbial culture results from infected incisions. The primary outcome was the incidence of SSI after EAS, while the secondary outcomes were postoperative hospital stay, ICU occupancy rate, length of ICU stay, hospitalization cost, and mortality within postoperative 30 days. Univariate and multivariate logistic regression models were used to analyze the risk factors of SSI after EAS.Results:A total of 660 EAS patients aged (47.9±18.3) years were enrolled in this study, including 56.5% of males (373/660). Forty-nine (7.4%) patients developed postoperative SSI. The main pathogen of SSI was Escherichia coli [culture positive rate was 32.7% (16/49)]. As compared to patients without SSI, those with SSI were more likely to be older (median 56 years vs. 46 years, U=19 973.5, P<0.001), male [71.4% (35/49) vs. 56.1% (343/611), χ 2=4.334, P=0.037] and diabetes [14.3% (7/49) vs. 5.1% (31/611), χ 2=5.498, P=0.015]; with-lower preoperative hemoglobin (median: 122.0 g/L vs. 143.5 g/L, U=11 471.5, P=0.006) and albumin (median: 35.5 g/L vs. 40.8 g/L, U=9452.0, P<0.001), with higher blood glucose (median: 6.9 mmol/L vs. 6.0 mmol/L, U=17 754.5, P<0.001); with intestinal obstruction [32.7% (16/49) vs. 9.2% (56/611), χ 2=25.749, P<0.001], with ASA score 3-4 [42.9% (21/49) vs. 13.9% (85/611), χ 2=25.563, P<0.001] and with high surgical risk [49.0% (24/49) vs. 7.0% (43/611), χ 2=105.301, P<0.001]. The main operative procedure resulting in SSI was laparotomy [81.6%(40/49) vs. 35.7%(218/611), χ 2=40.232, P<0.001]. Patients with SSI experienced significantly longer operation time (median: 150 minutes vs. 75 minutes, U=25 183.5, P<0.001). In terms of clinical outcome, higher ICU occupancy rate [51.0% (25/49) vs. 19.5% (119/611), χ 2=26.461, P<0.001], more hospitalization costs (median: 44 000 yuan vs. 15 000 yuan, U=24 660.0, P<0.001), longer postoperative hospital stay (median: 10 days vs. 5 days, U=23 100.0, P<0.001) and longer ICU occupancy time (median: 0 days vs. 0 days, U=19 541.5, P<0.001) were found in the SSI group. Multivariate logistic regression analysis showed that the elderly (OR=3.253, 95% CI: 1.178-8.985, P=0.023), colorectal surgery (OR=9.156, 95% CI: 3.655-22.937, P<0.001) and longer operation time (OR=15.912, 95% CI:6.858-36.916, P<0.001) were independent risk factors of SSI, while the laparoscopic surgery (OR=0.288, 95% CI: 0.119-0.694, P=0.006) was an independent protective factor for SSI. Conclusions:For patients undergoing EAS, attention should be paid to middle-aged and elderly patients and those of colorectal surgery. Laparoscopic surgery should be adopted when feasible and the operation time should be minimized, so as to reduce the incidence of SSI and to reduce the burden on patients and medical institutions.

OBJECTIVE: To analyze the current status of diagnosis and management of acute appendicitis (AA) in China. METHODS: Questionnaire survey was used to retrospectively collect data of hospitalized patients with AA from 43 medical centers nationwide in 2017 (Sort by number of cases provided: Jinling Hospital of Medical School of Nanjing University, The First Affiliated Hospital of Xinjiang Medical University, Lu'an People's Hospital, Tengzhou Central People's Hospital, Dalian Central Hospital, The Affiliated Hospital of Xuzhou Medical University, Dongying People's Hospital, Jinjiang Hospital of Traditional Chinese Medicine, Huangshan Shoukang Hospital, Xuyi People's Hospital, Nanjing Jiangbei People's Hospital, Lanzhou 940th Hospital of PLA, Heze Municipal Hospital, The First College of Clinical Medical Science of China Three Gorges University, Affiliated Jiujiang Hospital of Nanchang University, The Second People's Hospital of Hefei, Affiliated Central Hospital of Shandong Zaozhuang Mining Group, The Third People's Hospital of Kunshan City, Xuzhou First People's Hospital, The 81st Group Army Hospital of PLA, Linyi Central Hospital, The General Hospital of Huainan Eastern Hospital Group, The 908th Hospital of PLA, Liyang People's Hospital, The 901th Hospital of Joint Logistic Support Force, The Third Affiliated Hospital of Chongqing Medical University, The Fourth Hospital of Jilin University, Harbin Acheng District People's Hospital, The First Affiliated Hospital of Zhengzhou University, Nanjing Luhe People's Hospital, Taixing Municipal People's Hospital, Baotou Central Hospital, The Affiliated Hospital of Nantong University, Linyi People's Hospital, The 72st Group Army Hospital of PLA, Zaozhuang Municipal Hospital, People's Hospital of Dayu County, Taixing City Hospital of Traditional Chinese Medicine, Suzhou Municipal Hospital, Beijing Guang'anmen Hospital, Langxi County Hospital of Traditional Chinese Medicine, Nanyang Central Hospital, The Affiliated People's Hospital of Inner Mongolia Medical University).The diagnosis and management of AA were analyzed through unified summary. Different centers collected and summarized their data in 2017 and sent back the questionnaires for summary. RESULTS: A total of 8 766 AA patients were enrolled from 43 medical centers, including 4 711 males (53.7%) with median age of 39 years and 958 (10.9%) patients over 65 years old. Of 8 776 patients, 5 677 cases (64.6%) received one or more imaging examinations, and the other 3 099 (35.4%) did not receive any imaging examination. A total of 1 858 (21.2%) cases received medical treatment, mainly a combination of nitroimidazoles (1 107 cases, 59.8%) doublet regimen, followed by a single-agent regimen of non-nitroimidazoles (451 cases, 24.4%), a nitroimidazole-free doublet regimen (134 cases, 7.2%), a triple regimen of combined nitroimidazoles (116 cases, 6.3%), nitroimidazole alone (39 cases, 2.1%) and nitroimidazole-free triple regimen (3 cases, 0.2%). Of the 6 908 patients (78.8%) who underwent surgery, 4 319 (62.5%) underwent laparoscopic appendectomy and 2589 (37.5%) underwent open surgery. Ratio of laparotomy was higher in those patients under 16 years old (392 cases) or over 65 years old (258 cases) [15.1%(392/2 589) and 10.0%(258/2 589), respectively, compared with 8.5%(367/4 316) and 8.0%(347/4 316) in the same age group for laparoscopic surgery, χ²=91.415, P<0.001; χ²=15.915,P<0.001]. Patients with complicated appendicitis had higher ratio of undergoing open surgery as compared to those undergoing laparoscopic surgery [26.7%(692/2 589) vs. 15.6%(672/4 316), χ²=125.726, P<0.001].The cure rates of laparoscopic and open surgery were 100.0% and 99.8%(2 585/2 589) respectively without significant difference (P=0.206). Postoperative complication rates were 4.5%(121/2 589) and 4.7%(196/4 316) respectively, and the difference was not statistically significant (χ²=0.065, P=0.799). The incidence of surgical site infection was lower (0.6% vs. 1.7%, χ²=17.315, P<0.001), and hospital stay was shorter [6(4-7) days vs. 6(5-8) days, U=4 384 348.0, P<0.001] in the laparoscopic surgery group, while hospitalization cost was higher (median 12 527 yuan vs. 9 342 yuan, U=2 586 809.0, P<0.001). CONCLUSIONS The diagnosis of acute appendicitis is still clinically based, supplemented by imaging examination. Appendectomy is still the most effective treatment at present. Laparoscopic appendectomy has become the main treatment strategy, but anti-infective drugs are also very effective.
Acute Disease ; Adolescent ; Adult ; Aged ; Anti-Bacterial Agents ; therapeutic use ; Appendectomy ; Appendicitis ; diagnosis ; therapy ; China ; Female ; Health Care Surveys ; Humans ; Laparoscopy ; Male ; Middle Aged ; Retrospective Studies ; Treatment Outcome ; Young Adult

Objective: To investigate the diagnosis and treatment for enterocutaneous fistula (ECF) in China, and to explore the prognostic factors of ECF. Methods: A multi-center cross-sectional study was conducted based on the Registration System of Chinese Gastrointestinal Fistula and Intra-Abdominal Infections to collect the clinical data of ECF patients from 54 medical centers in 22 provinces/municipalities from January 1, 2018 to December 31, 2018. The clinical data included patient gender, age, length of hospital stay, intensive care unit (ICU) admission, underlying diseases, primary diseases, direct causes of ECF, location and type of ECF, complications, treatment and outcomes. All medical records were carefully filled in by the attending physicians, and then re-examined by more than two specialists. The diagnosis of ECF was based on the clinical manifestations, laboratory/imaging findings and intraoperative exploration. Results: A total of 1521 patients with ECF were enrolled, including 1099 males and 422 females, with a median age of 55 years. The top three primary diseases of ECF were malignant tumors in 626 cases (41.2%, including 540 gastrointestinal tumors, accounting for 86.3% of malignant tumors), gastrointestinal ulcers and perforations in 202 cases (13.3%), and trauma in 157 cases (10.3%). The direct causes of ECF were mainly surgical operation in 1194 cases (78.5%), followed by trauma in 156 (10.3%), spontaneous fistula due to Crohn′s disease in 92 (6.0%), radiation intestinal injury in 41 (2.7%), severe pancreatitis in 20 (1.3%), endoscopic treatment in 13 (0.9%) and 5 cases (0.3%) of unknown reasons. All the patients were divided into three groups: 1350 cases (88.7%) with simple ECF, 150 (9.9%) with multiple ECF, and 21 (1.4%) with combined internal fistula. Among the patients with simple ECF, 438 cases (28.8%) were jejuno-ileal fistula, 313 (20.6%) colon fistula, 170 (11.2%) rectal fistula, 111 (7.3%) duodenal fistula, 76 (5.0%) ileocecal fistula, 65 (4.3%) ileocolic anastomotic fistula, 55 (3.6%) duodenal stump fistula, 36 (2.4%) gastrointestinal anastomotic fistula, 36 (2.4%) esophagogastric/esophagojejunal anastomotic fistula, 29 (1.9%) gastric fistula and 21 (1.4%) cholangiopancreatiointestinal. Among all the simple ECF patients, 991 were tubular fistula and 359 were labial fistula. A total of 1146 patients finished the treatment, of whom 1061 (92.6%) were healed (586 by surgery and 475 self-healing) and 85 (7.4%) died. A total of 1043 patients (91.0%) received nutritional support therapy, and 77 (6.7%) received fistuloclysis. Infectious source control procedures were applied to 1042 patients, including 711 (62.0%) with active lavage and drainage and 331 (28.9%) with passive drainage. Among them, 841 patients (73.4%) underwent minimally invasive procedures of infectious source control (replacement of drainage tube through sinus tract, puncture drainage, etc.), 201 (17.5%) underwent laparotomy drainage, while 104 (9.1%) did not undergo any drainage measures. A total of 610 patients (53.2%) received definitive operation, 24 patients died within postoperative 30-day with mortality of 3.9% (24/610), 69 (11.3%) developed surgical site infection (SSI), and 24 (3.9%) had a relapse of fistula. The highest cure rate was achieved in ileocecal fistula (100%), followed by rectal fistula (96.2%, 128/133) and duodenal stump fistula (95.7%,44/46). The highest mortality was found in combined internal fistula (3/12) and no death in ileocecal fistula. Univariate prognostic analysis showed that primary diseases as Crohn′s disease (χ²=6.570, P=0.010) and appendicitis/appendiceal abscess (P=0.012), intestinal fistula combining with internal fistula (χ²=5.460, P=0.019), multiple ECF (χ²=7.135, P=0.008), esophagogastric / esophagojejunal anastomotic fistula (χ²=9.501, P=0.002), ECF at ileocecal junction (P=0.012), non-drainage/passive drainage before the diagnosis of intestinal fistula (χ²=9.688, P=0.008), non-drainage/passive drainage after the diagnosis of intestinal fistula (χ²=9.711, P=0.008), complicating with multiple organ dysfunction syndrome (MODS) (χ²=179.699, P<0.001), sepsis (χ²=211.851, P<0.001), hemorrhage (χ²=85.300, P<0.001), pulmonary infection (χ²=60.096, P<0.001), catheter-associated infection (χ²=10.617, P=0.001) and malnutrition (χ²=21.199, P<0.001) were associated with mortality. Multivariate prognostic analysis cofirmed that sepsis (OR=7.103, 95%CI:3.694-13.657, P<0.001), complicating with MODS (OR=5.018, 95%CI:2.170-11.604, P<0.001), and hemorrhage (OR=4.703, 95%CI: 2.300-9.618, P<0.001) were independent risk factors of the death for ECF patients. Meanwhile, active lavage and drainage after the definite ECF diagnosis was the protective factor (OR=0.223, 95%CI: 0.067-0.745, P=0.015). Conclusions The overall mortality of ECF is still high. Surgical operation is the most common cause of ECF. Complications e.g. sepsis, MODS, hemorrhage, and catheter-associated infection, are the main causes of death. Active lavage and drainage is important to improve the prognosis of ECF.

OBJECTIVETo analyze the stress distribution of bone around the implant on vertical loads.

METHODSFour linear strain gauges were placed in strategic locations. The vertical loads were applied at different points. The result of the stress was recorded at each gauge.

RESULTSThe load, the location of load and their interactions indicated statistically significant difference in the distribution of stress. For the single-implant-supported fixed prosthesis the greater stress values were showed at the strain gauges positioned in the implant's cervical and apical area near to loading points. For the two-implant-supported fixed bridge the greater stress values were showed at the stress gauges positioned in the two implants cervical and apical area near to loading points, especially at the implant near to loading points. As loads were applied at the cantilevered points, the magnitude of stress was directly proportional to the magnitude of load and the cantilevered length.

CONCLUSIONSFor the design of the implant-supported prosthesis the relief of load and the avoidance of cantilevered prosthesis should be considered to reduce the stress of the bone around the implant.

Bite Force ; Dental Implantation, Endosseous ; Dental Prosthesis, Implant-Supported ; Dental Stress Analysis ; Denture, Partial, Fixed ; Elasticity ; Humans

OBJECTIVETo evaluate mice as experimental animals for Chlamydia pneumoniae (C. pneumoniae) infection and investigate the pathogenesis of C. pneumoniae derived pneumonitis.

METHODSIcr mice were inoculated with the C. pneumoniae strain, CWL-029, either intranasally or intravenously. After a single dose inoculation, mice were killed on the 1st, 3rd, 7th, 14th, 21st, 28th and 60th days. The pathological changes in lung tissue were analyzed.

RESULTSThe Icr mice were shown to be susceptible to C. pneumoniae. Inoculation into mice with C. pneumoniae induced a prolonged course of lung infection, as demonstrated by persistence of lung pathology (up to 60 days). Via intranasal inoculation of mice, lung pathology was characterized by patchy interstitial pneumonitis with predominantly neutrophil leukocyte infiltration early (within the first 7 days) and lymphocyte infiltration in the later stages (14 days later) of infection. After intravenous inoculation, a similarly developed interstitial pneumonitis was observed, but it was milder and patchier, especially in early stages. C. pneumoniae DNA was detected by polymerase chain reaction (PCR) intermittently in the lung tissue. Inoculated mice developed serum IgG antibody responses.

CONCLUSIONThe Icr mice were susceptible to C. pneumoniae, resulting in a pulmonary infection characterized by interstitial pneumonitis, occurring most strongly via intranasal inoculation.

Animals ; Chlamydia Infections ; etiology ; pathology ; Chlamydophila pneumoniae ; DNA, Bacterial ; analysis ; Lung ; pathology ; Male ; Mice ; Mice, Inbred ICR ; Pneumonia, Bacterial ; etiology ; pathology ; Polymerase Chain Reaction