Objective To investigate the biocompatibility and biodegradability of mini-implants of PLA-based composites in experimental animals by histomorphometry, and to study its clinical application in orthodontic treatment. Methods Six adult male Beagle dogs were randomly divided into 3 groups, a total of 72 mini-implants were implanted to the mandibular. Two Beagle dogs were sacrificed at 2 months、4 months and 6 months after surgery. Animals were intramuscularly injected with tetracycline on 14 and 4 days before sacrifice. Mandibular specimens and the surfaces of mini-implants were examined with Cone beam CT, CBCT and Scanning Electronic Microscopy and SEM respectively. Histopathologocal changes were observed with toluidine blue staining and HE staining. Results The results of CBCT assay showed that the mini-implants were gradually radiopacity with the extension of time. SEM assay showed that the morphology of mini-implants surface was significantly changed;micro-implants degradation occured gradually.New bone formation was observed around the micro-implants within 10 days.Toluidine blue staining showed the formation of new bone around the mini-implants. However, the inflamma-tion around the implants was not observed. Conclusion The biocompatibility of biodegradable mini-implant is good. This mini-implant is biodegradable in vivo and can promote the formation of the surrounding bone tissue.

BACKGROUND: This study aimed to determine the potential protective effect of inducing hypertransfusion to the gastrointestinal tract following a porcine model of cardiac arrest and cardiopulmonary resuscitation (CPR) by evaluating the influence of gastrointestinal ultrastructure, ATPase and serum diamine oxidase. METHODS: Ventricular fibrillation was induced by programmed electrical stimulation in 16 male domestic pigs (n=8/group). Four minutes after ventricular fibril ation, CPR was performed. The pigs that successfully restored spontaneous circulation received intravenous infusion of either norepinephrine to maintain the mean arterial pressure at 130％ of the baseline before ventricular fibril ation or normal saline. Serum diamine oxidase and gastrointestinal ATPase activity were determined, and histopathological examination of the gastrointestinal tract was performed by light and electron microscopy. RESULTS: CPR caused significant injury to the gastrointestinal tract, elevating serum diamine oxidase and causing destruction of intestinal microvillus in control animals. Na+-K+ ATPase and Ca2+ATPase activity in gastric tissue were significantly elevated in animals receiving hypertransfusion treatment compared with the control animals. Hypertransfusion also significantly reduced serum diamine oxidase to below control levels after CPR. Moreover, severe injury sustained by the gastrointestinal tissue was markedly ameliorated under hypertransfusion conditions compared with the control animals. CONCLUSIONS: Gastrointestinal injury and abnormal energy metabolism were strikingly evident following CPR. Hypertransfusion inducing hypertension can improve energy metabolism and ameliorate gastrointestinal mucosal injury, indicating that hypothermia significantly ameliorates gastrointestinal injury sustained following cardiac arrest.

Astragalus membranaceus ; chemistry ; Cell Line ; Cytokines ; metabolism ; Humans ; Inflammation ; Macrophages ; drug effects ; metabolism ; Monocytes ; drug effects ; metabolism ; Polysaccharides ; pharmacology

Objective:To discuss the relationship between heart rate (HR) and heart rate differences (HRD) at different time points in head-up tilt test (HUTT) and the occurrence of postural tachycardia syndrome(POTS) in children and adolescents.Methods:A total of 217 children and adolescents diagnosed as POTS, who complained of syncope or presyncope, were chosen as POTS group (aged 6 to 16 years). During the same period, 73 healthy children and adolescents with matching gender and age were selected as control group.All subjects underwent HUTT from October 2000 to November 2019.Get HR (HR0, HR5, HR10) in baseline, HUTT 5 min and 10 min, HRD (HRD5, HRD10) of HR in HUTT 5 min and 10 min minus HR in baseline.Results:(1) HR5, HR10, HRD5, and HRD10 were higher in the POTS group than those in the control group( P<0.05). (2) Univariate Logistic regression: There was a correlation between HR5, HR10, HRD5, HRD10 and the risk of POTS( P<0.01). (3) Multivariable Logistic regression: For each additional unit of HRD5 and HRD10, the risk of POTS increased by 27% ( OR=1.27, 95% CI1.16 to 1.36) and 28% ( OR=1.28, 95% CI1.20 to 1.38). Conclusion:HR and HRD are related with the occurrence of POTS in children and adolescents, but HR and HRD at different time points of HUTT play the little role on the effect size of the occurrence of POTS.

?In allusion to the training requirements of eight-year program medical students, combining with our own experience in teaching this type of the students in ophthalmology, we have done some thinking about the training methods of eight-year program medical students in order to improving their comprehensive abilities of ophthalmology. Several suggestions are made in various aspects, including the study of the basic theory of ophthalmology, the training of doctor - patient communication skills, the training of basic clinical skills, the interest developments in ophthalmology subspecialty areas and the training of basic experiment skills.

BACKGROUNDDuring cardiac arrest, the gastrointestinal tract is sensitive to ischemia. Protection of the gastrointestinal tract is a critical factor in determining prognosis following cardiopulmonary resuscitation (CPR). This study seeks to determine the extent of gastrointestinal tract injury and the potential protective effect of inducing hypothermia following a porcine cardiac arrest model and CPR.

METHODSVentricular fibrillation was induced by programmed electrical stimulation in 16 male domestic pigs (n = 8 per group). Four minutes after ventricular fibrillation, CPR was performed. Pigs that successfully restored spontaneous circulation then received intravenous infusions of saline at either 4°C or room temperature to produce hypothermic and control conditions respectively. Serum diamine oxidase and gastrointestinal adenosine triphosphate enzyme activity were determined and histopathology of the gastrointestinal tract was performed by light microscopy and electron microscopy.

RESULTSSignificant injury of the gastrointestinal tract after CPR was found. Na(+)-K(+) and Ca(2+) adenosine triphosphate enzyme activity in the gastric tissue were significantly high in animals receiving hypothermia treatment compared to controls. Hypothermia also significantly reduced serum diamine oxidase after CPR compared to the control group. Moreover, severe injury sustained by the gastrointestinal tissue was significantly ameliorated under hypothermic conditions compared to controls.

CONCLUSIONSGastrointestinal injury and abnormal energy metabolism are strikingly evident following CPR. Hypothermia, which is induced by an infusion of 4°C saline, can rapidly reduce internal body temperature, improve energy metabolism, and ameliorate injury to the gastrointestinal mucosa after CPR.

Animals ; Cardiopulmonary Resuscitation ; adverse effects ; Disease Models, Animal ; Energy Metabolism ; Gastrointestinal Tract ; injuries ; Heart Arrest ; therapy ; Hypothermia, Induced ; methods ; Male ; Swine

Imaging plays a key role in the diagnosis and decision-making process including pre-treatment planning, surgical strategy, and follow-up. The critical point in diagnosis of presacral recurrent rectal cancer by imaging modalities is to distinguish the recurrent tumor from nonmalignant tissues induced by operation or radiotherapy. The practice guideline recommends CT as surveillance imaging modality for recurrent rectal cancer. MRI shows higher accuracy, sensitivity, and specificity in diagnosis of presacral recurrent rectal cancer compared with CT. If CT or MRI can not make final diagnosis in challenging cases, 18-fluorodeoxyglucose positron emission tomography ( 18FDG PET) is recommended to aid diagnosis with high sensitivity and specificity, though false-positivity and negativity should be considered. If new or enlarging soft tissue are shown in the follow-up examination, tumor recurrence should be suspected. In addition, tumor-related high risk factors, treatment protocol, surgery, quality of specimen and pathological stages should also be considered when presacral recurrent rectal cancer is to be diagnosed.

Imaging plays a key role in the diagnosis and decision-making process including pre-treatment planning, surgical strategy, and follow-up. The critical point in diagnosis of presacral recurrent rectal cancer by imaging modalities is to distinguish the recurrent tumor from nonmalignant tissues induced by operation or radiotherapy. The practice guideline recommends CT as surveillance imaging modality for recurrent rectal cancer. MRI shows higher accuracy, sensitivity, and specificity in diagnosis of presacral recurrent rectal cancer compared with CT. If CT or MRI can not make final diagnosis in challenging cases, 18-fluorodeoxyglucose positron emission tomography ( 18FDG PET) is recommended to aid diagnosis with high sensitivity and specificity, though false-positivity and negativity should be considered. If new or enlarging soft tissue are shown in the follow-up examination, tumor recurrence should be suspected. In addition, tumor-related high risk factors, treatment protocol, surgery, quality of specimen and pathological stages should also be considered when presacral recurrent rectal cancer is to be diagnosed.

Objective:To investigate the circadian rhythm of blood pressure and morning blood pressure surge (MBPS) in children with neurally mediated syncope (NMS).Methods:From July 2018 to June 2019, 135 cases [aged 3-16 years old (10.12±2.53) years old, with 74 males and 61 females] with unexplained syncope, presyncope, and symptoms such as headache, dizziness, chest pain, and chest tightness were collected in the Second Xiangya Hospital, Central South University for the first time.The 24 hour ambulatory blood pressure monitoring (24 h ABPM) was completed on the same day of the head-up tilt test (HUTT). Patients were divided into HUTT negative and positive groups, and dippers and non-dippers groups. MBPS (sleep-trough surge) was calculated and compared respectively.Results:(1) There were 51 patients in the HUTT positive group, including 27 patients with vasovagal syncope, 23 patients with postural orthostatic tachycardia syndrome, and 1 patient with orthostatic hypotension. In HUTT positive group, there were 22 cases (43.14%) of dippers and 29 cases of non-dippers.There were 84 patients in the HUTT negative group, there were 32 cases (38.10%) of dippers and 52 cases of non-dippers. There were no statistical significances in the dipper proportion between HUTT positive and negative group ( χ2=1.305, P>0.05). (2) Sleep-trough systolic blood pressure (SBP) surge was 1-45 mmHg [(15.97±8.03) mmHg](1 mmHg=0.133 kPa), and sleep-trough diastolic blood pressure (DBP) surge was -6-43 mmHg[(14.05±7.97) mmHg]. There were no statistical significances in sleep-trough surge between the HUTT negative and positive group (all P>0.05). (3) The age in the dipper group was higher than that in the non-dipper group [(10.72±2.20) years old vs. (9.72±2.66) years old, t=2.288, P<0.05]. The daytime average SBP [(110.20±8.33) mmHg vs.(105.54±7.51) mmHg, t=3.381, P<0.01], and morning peak SBP [(109.99±10.19) mmHg vs.(106.63±8.71) mmHg, t=2.045, P<0.05] of the dipper group were higher than those of the non-dipper group.The nighttime average SBP[(95.41±7.50) mmHg vs.(98.59±6.88) mmHg, t=2.540, P<0.01], nighttime average DBP[(48.61±4.52) mmHg vs.(52.28±4.65) mmHg, t=4.547, P<0.01], nocturnal minimum SBP[(89.62±8.18) mmHg vs.(93.60±7.38) mmHg, t=2.940, P<0.01], and nocturnal minimum DBP[(44.99±5.32) mmHg vs.(49.01±5.54) mmHg, t=4.205, P<0.01] of the dipper group were lower than that of the non-dipper group.Nocturnal SBP reduction rate [(13.42±2.68)% vs.(6.48±2.49)%, t=15.384, P<0.01], nocturnal DBP reduction rate[(19.98±4.92)% vs.(12.46±5.05)%, t=8.561, P<0.01], sleep-trough SBP surge[(20.37±8.30) mmHg vs.(13.03±6.36) mmHg, t=5.800, P<0.01], and sleep-trough DBP surge[(16.91±8.06) mmHg vs.(12.13±7.36) mmHg, t=3.554, P<0.01] of the dipper group were higher than those of the non-dipper group. Conclusions:Nocturnal blood pressure reduction and sleep-trough surge decreased in NMS children, and there is a circadian rhythm disorder of blood pressure.