Impacts of residual 3D printing metal powders on immunological response and bone regeneration: an in vivo study.

Residual powder is a defect in powder bed fusion-based additive manufacturing (3D printing), and it is difficult to completely remove it from as-printed materials. In addition, it is not necessary to apply 3D printed implants with residual powder in the clinic. The immunological response triggered by the residual powder is an important area of study in medical research. To further understand the possible immunological reactions and hidden dangers caused by residual powders in vivo, this study compared the immunological reactions and osteolysis caused by typical powders for four implant materials: 316 L stainless steel, CoCrMo, CP-Ti, and Ti-6Al-4V (particle size range of 15-45 µm), in a mouse skull model. Furthermore, the possible immunological responses and bone regeneration induced by the four 3D printed implants with residual powder in a rat femur model were compared. In the mouse skull model, it was found that the 316L-S, CoCrMo-S, and especially the 316L-M powders, upregulated the expression of pro-inflammatory factors, increased the ratio of RANKL/OPG, and activated more functional osteoclasts, resulting in more severe bone resorption compared with those in other groups. In the rat femur model, which is more suitable for clinical practice, there is no bone resorption in implants with residual powders, but they show good bone regeneration and integration ability because of their original roughness. The results indicate that the expressions of inflammatory cytokines in all experimental groups were the same as those in the control group, showing good biological safety. The results answered some critical questions related to additively manufactured medical materials in vivo and indicated that as-printed implants may have great potential in future clinical applications.

[Epidemiological Survey on Intestinal Parasitic Infections in Lhasa City in 2014].

Objective: To investigate the prevalence of parasitic infections in Lhasa, Tibet. Methods: The residents in Chengguan District, Dangxiong County, Dazi County and Qushui County were selected to participate in the study in 2014, using the stratified random sampling method. Infections with the soil-borne nematodes in feces were examined in triplicates using the Kato-Katz method. Further, the Enterobius vermicularis were examined using the cellophane anal swab method in children aged 3-12 years, and the intestinal protozoa were detected by iodine staining. The parasitic infection was analyzed by sex, age, and occupation. Comparisons were made using Chi-square test. Results: A total of 1 015 residents（39.3±18.2 years: age range, 1-89 years） participated in the study, including 391 males（38.6%） and 623 females（61.4%）. Two hundred and forty-nine participants were positive for parasitic infections, with an overall infection rate of 24.5%（249/1 015）. The infection rate was 21.7%（220/1 015） for Taenia sp., 0.2%（2/1 015） for Trichuris trichiura and E. vermicularis respectively, 4.1%（42/1 015） for Entamoeba coli, 0.4%（4/1 015） for Giardia lamblia, 0.2%（2/1 015） for Iodamoeba butschlii. No infection was found for other parasites. There was no significant sexual difference in the infection rate of Taenia (male 21.2%, 83/391; female 22.0%, 137/624), T. trichiura (male 0; female 0.3%, 2/624), E. vermicularis (male 0.3%, 2/391; female 0.2%, 1/624), E. coli (male 5.4%, 21/391; female 3.4%, 21/624), G. lamblia (male 0.8%, 3/391; female 0.2%, 1/624), or I. butschlii (male 0; female 0.3%, 2/624) (P>0.05). The Taenia sp. infection rate in the age groups of 0-17, 18-29, 30-39, 40-49, 50-59 and ≥ 60 years was 10.9%（18/165）, 14.0%（18/129）, 23.0%（43/187）, 25.3%（61/241）, 26.5%（41/155）, and 28.3%（39/138）, respectively, with significant differences between groups of 0-17 and 40-49 years and between groups of 50-59 and ≥ 60 years (P<0.01). The infection rate of E. coli, T. trichiura and I. butschlii was highest in the age group of 50-59 years（6.5%, 10/155; 0.7%, 1/155; 1.3%, 2/155 respectively）. Among various occupations, farmers showed the highest infection rate for Taenia（44.5%, 147/330）, E. coli（6.4%, 21/33）, E. vermicularis （0.6%, 2/330） and I. butschlii（0.3%, 1/330）; housewives had the highest infection rate for T. trichiura（2.5%, 1/40）; and the students had the highest infection rate for G. lamblia (0.7%, 1/134). Conclusion: There are infections with various intestinal parasites in the participants of Lhasa City, among which taenia infection reaches 20.7% while others have a low level of infection.

Association of Office and Ambulatory Blood Pressure with Left Ventricular Structure and Function in Hypertensive Patients.

Objective: The current study was to evaluate the association of office blood pressure (OBP) and 24h ambulatory blood pressure (ABP) with left ventricular (LV) structure and function in hypertensive patients. Whether the association was modified by sex was also evaluated. Methods: A total of 694 hypertensive patients without cardiovascular disease were retrospectively included from the inpatient clinic. Regression analysis was performed to evaluate the association of OBP and 24h ABP parameters with LV mass index (LVMi), e' velocity and left ventricular hypertrophy (LVH) with adjustment for covariates including age, obesity, diabetes mellitus, obstructive sleep apnea, estimated glomerular filtration rate and antihypertensive drugs. Results: There was no difference in OBP by sex. Compared to women, men had a higher 24h (132.6 ± 11.3 vs 129.3 ± 10.0 mm Hg), daytime (136.6 ± 12.9 vs 132.8 ± 9.5 mm Hg) and nighttime (130.3 ± 9.2 vs 125.1 ± 6.6 mm Hg) SBP. The proportion of patients with non-dipping pattern and reverse dipper pattern was also higher in men. In the overall participants, 24h, daytime and nighttime SBP, non-dipping and reverse dipper pattern were associated with LVMi, e' velocity and LVH, which were not observed in OBP. The magnitude of the association between 24h, daytime and nighttime SBP, non-dipping and reverse dipper pattern with LVMi, e' velocity and LVH was stronger in men than in women (P-value for interaction <0.05). Conclusion: Twenty-four-hour ABP appears to be better than OBP in association with LV structural and functional alterations, and this association was modified by sex.