Associations Between Blood Trace Element Levels and Nutritional Status in Maintenance Hemodialysis.

OBJECTIVE(S): We aimed to investigate the associations between blood trace element levels and nutritional status in patients undergoing maintenance hemodialysis (MHD). METHODS: This cross-sectional study included patients undergoing MHD who were treated at our center in September 2019. Clinical and demographic data and blood samples were collected before hemodialysis sessions, and the levels of manganese, lead, selenium, zinc, and copper were measured by inductively coupled plasma mass spectrometry. The Simplified Nutritional Appetite Questionnaire scale was used to assess patient appetite. Skinfold thickness, bicep circumference, upper arm muscle circumference, 7-point Subjective Global Assessment, Nutritional Risk Screening 2002 (NRS 2002), and Geriatric Nutritional Risk Index (GNRI) were used to assess patient nutritional status. Univariate and multivariate logistic regression analyses were performed to study the relationship between trace elements and nutritional indicators. RESULTS: In total, 118 patients (64 males and 54 females) were included, with a median dialysis vintage of 34.0 months (16.0-54.5 months) and an average age of 63.20 ± 14.26 years. Malnourished patients, as defined by the GNRI, Subjective Global Assessment, and NRS 2002, accounted for 28.0%, 49.2%, and 26.3% of enrolled patients, respectively. The multivariate binary logistic regression showed that higher blood copper levels were independently associated with nutritional risk defined as GNRI ≤91.2 (odds ratio [OR] = 1.003, 95% confidence interval [CI] = 1.000-1.006; P = .020), whereas lower blood zinc levels (OR = 0.634, 95% CI = 0.439-0.916; P = .015), blood zinc < 4.220 mg/L (OR = 3.723, 95% CI = 1.274-10.879; P = .016), lower blood selenium levels (OR = 0.959, 95% CI = 0.929-0.990; P = .010), and blood selenium < 85 µg/L (OR = 5.568, 95% CI = 1.039-29.840; P = .045) were independently associated with a nutritional risk defined as NRS 2002 ≥ 3. CONCLUSION(S): Higher levels of blood copper and lower levels of blood zinc and selenium were independently associated with higher nutritional risk in MHD patients.

Structural design of gradient porous dental implant based on orthogonal test.

OBJECTIVES: To solve the current problems of loosening and dislodging caused by the high elastic modulus of solid implants, we attempted to study a gradient porous dental implant that can lower the stress concentration and reduce the elastic modulus. METHODS: SolidWorks software was utilized to design the abutment and mechanical structure of the gradient porous implant. The mechanical properties of the gradient porous implant were evaluated by an orthogonal experimental design from four aspects: pore shape, pore diameter, porous layer height, and circumferential distribution. ANSYS software was used to evaluate the distribution of Von-Mises stress in the implant and its surrounding bone tissues under different structural combination parameters to derive the optimal combination of gradient porous implant parameters. RESULTS: The effects of the four factors, namely, pore shape, pore diameter, porous layer height and pore distribution, on the maximum Von-Mises stress on the implant were as follows. As the pore shape became smaller and the circumferential distribution decreased, the Von-Mises stress decreased significantly. The pore diameter went from 500 µm to 600 µm and then to 700 µm. The Von-Mises stress decreased and then increased. It increased with the increase in the height of the porous layer. CONCLUSIONS: The final optimal combination of parameters for the gradient porous implant was as follows: square pore shape, pore diameter of 600 µm, porous layer height of 3 mm, and quadratic step in pore distribution.

Lower Levels of Blood Zinc Associated with Intradialytic Hypertension in Maintenance Hemodialysis Patients.

Intradialytic hypertension (iHTN) has been related with an increased risk of mortality, with imbalances in trace elements being frequent in maintenance hemodialysis (MHD) patients. The aim of this study was to analyze the relationships between the levels of blood trace elements and iHTN in MHD patients. A total of 144 MHD patients were enrolled in September, 2019 (66 females; 5616 hemodialysis treatments), with a mean age of 64.33 ± 13.39 years and median vintage of 33.50 (16.25-57.50) months. Patients exhibited an average peridialytic systolic blood pressure (SBP) change of - 4.18 ± 20.22 mm Hg in the next 3 months. Thirty-four (23.6%) patients had persistent iHTN (piHTN). These patients were characterized by older age, higher rate of hypozincemia, and modified Charlson comorbidity score, whereas lower blood zinc and hemoglobin, at the time of their recruitment. No significant difference in the levels of other blood trace elements was observed between groups. A general linear mixed (GLM) model showed that with every mg/L point lower mean blood zinc at baseline, the peridialytic SBP change was increased by 4.524 mm Hg (P < 0.001). Binary logistic model in modulate of the GLM model revealed that the lower level of blood zinc was associated with piHTN (OR = 0.433, 95 % CI 0.295 to 0.637, P < 0.001). Multivariate analysis confirmed both above results. Our study indicated that lower blood zinc was independently associated with piHTN in patients undergoing MHD, but prospective studies with larger population are still needed.