Valentinas Uvarovas

Relevance of HCN2-expressing human mesenchymal stem cells for the generation of biological pacemakers

BackgroundThe transfection of human mesenchymal stem cells (hMSCs) with the hyperpolarization-activated cyclic nucleotide-gated ion channel 2 (HCN2) gene has been demonstrated to provide biological pacing in dogs with complete heart block. The mechanism appears to be the generation of the ion current (If) by the HCN2-expressing hMSCs. However, it is not clear how the transfection process and/or the HCN2 gene affect the growth functions of the hMSCs. Therefore, we investigated survival, proliferation, cell cycle, and growth on a Kapton® scaffold of HCN2-expressing hMSCs.MethodshMSCs were isolated from the bone marrow of healthy volunteers applying a selective cell adhesion procedure and were identified by their expression of specific surface markers. Cells from passages 2–3 were transfected by electroporation using commercial transfection kits and a pIRES2-EGFP vector carrying the pacemaker gene, mouse HCN2 (mHCN2). Transfection efficiency was confirmed by enhanced green fluorescent protein (EGFP) fluorescence, quantitative real-time polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). After hMSCs were transfected, their viability, proliferation, If generation, apoptosis, cell cycle, and expression of transcription factors were measured and compared with non-transfected cells and cells transfected with pIRES2-EGFP vector alone.ResultsIntracellular mHCN2 expression after transfection increased from 22.14 to 62.66 ng/mg protein (p < 0.05). Transfection efficiency was 45 ± 5 %. The viability of mHCN2-transfected cells was 82 ± 5 %; they grew stably for more than 3 weeks and induced If current. mHCN2-transfected cells had low mitotic activity (10.4 ± 1.24 % in G2/M and 83.6 ± 2.5 % in G1 phases) as compared with non-transfected cells (52–53 % in G2/M and 31–35 % in G1 phases). Transfected cells showed increased activation of nine cell cycle-regulating transcription factors: the most prominent upregulation was of AMP-dependent transcription factor ATF3 (7.11-fold, p = 0.00056) which regulates the G1 phase. mHCN2-expressing hMSCs were attached and made anchorage-dependent connection with other cells without transmigration through a 12.7-μm thick Kapton® HN film with micromachined 1–3 μm diameter pores.ConclusionsmHCN2-expressing hMSCs preserved the major cell functions required for the generation of biological pacemakers: high viability, functional activity, but low proliferation rate through the arrest of cell cycle in the G1 phase. mHCN2-expressing hMSCs attached and grew on a Kapton® scaffold without transmigration, confirming the relevance of these cells for the generation of biological pacemakers.

A mini volume loading test for indication of preoperative dehydration in surgical patients.

BACKGROUND AND OBJECTIVE Previously, a mini volume loading test (mVLT) detected signs of dehydration in healthy volunteers after an overnight fast. Our objective was to investigate whether mVLT could indicate preoperative dehydration in patients after an overnight fast. MATERIALS AND METHODS The mVLT was performed in 36 elective primary total knee arthroplasty patients. Each subject received three fluid challenges before anesthesia induction. These consisted of 5 mL/kg boluses of Ringers acetate infused over 3-5 min and followed by a 5-min period without fluids. Invasive (arterial, venous) and noninvasive (capillary) measurements of hemoglobin concentration were performed before and after each fluid challenge, as well as after a 20-min period without fluids which followed the last bolus. Arterial, venous and capillary plasma dilutions were calculated in every data point. Dilution values were used to calculate the plasma dilution efficacy of each fluid challenge. RESULTS Venous dilution was higher than capillary after the first fluid challenge (P=0.030), but lower than capillary after 20 min period following the last bolus (P=0.009). Arterial dilution was lower than capillary (P=0.005) after 20 min following the last bolus. Veno-capillary and arterio-capillary plasma dilution efficacy differences decreased (P=0.004 and P=0.033, respectively) from positive to negative during mVLT. These are signs of re-hydration from pre-existing dehydration according to a transcapillary reflux model. CONCLUSIONS Signs of dehydration were observed during mVLT in patients after pre-operative overnight fast. A revised transcapillary reflux model was proposed to explain the results.

Age, Sex, Body Mass Index, Education, and Social Support Influence Functional Results After Total Knee Arthroplasty

Introduction: Total knee arthroplasty (TKA) is an effective treatment for knee osteoarthritis. Patient-reported outcome after TKA is influenced by multiple patient-related factors. The aim of this study was to prospectively evaluate preoperative patient-related factors and to compare the self-reported outcomes 1 year after TKA among groups differing by age, sex, body mass index (BMI), education, and social support level. Methods: 314 patients, who underwent TKA in Vilnius Republican University Hospital between the end of 2012 and the middle of 2014, were included in a study. The preoperative and 12-month follow-up measurements were obtained using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Short Form-12 (SF-12). Differences between patient groups according to gender, age, BMI, level of education, and level of social support were analyzed. Results: At 12-month follow-up men demonstrated better results than women in WOMAC (P = .003) and SF-12 both domains (P < .05). Patients with a higher social support demonstrated higher scores in physical function according to SF-12 (P = .008). Better preoperative WOMAC and SF-12 scores were a predictor of better outcome 1 year after surgery. There was no difference in postoperative scores in different age, BMI, and education groups according to WOMAC and SF-12. Conclusion: There is no difference in self-reported functional outcome between patient groups differing in age, BMI, and education. Men and socially supported patients demonstrate better postoperative functional results 12 months after TKA. Better preoperative knee function and overall physical and mental function are predictors of better outcome 1 year after TKA. Age and obesity should not be limiting factors when considering who should receive this surgery.

Dubens nepakankamumo lūžiai: diagnostika ir gydymo prioritetai

As the average of people lives increases pelvic insufficiency fractures, their timely diagnosis and treatment are becoming more severe problem. Purpose of this article is to review the main literature databases and provide relevant, diagnostic and therapeutic principles applicable to the pelvic insufficiency fractures. This literature review includes data from articles in Pubmed and Cochrane databases. Also overview and available data are provided from Republican Vilnius University Hospital which focuses on pelvic insufficiency fracture treatment. Lithuanian hospitals do not have a common database and conducted extensive research, which could be reliable to identify exact number of pelvic insufficiency fractures. Risk factors which impact fracture deficiencies are: long-term use of corticosteroids, rheumatoid arthritis, lumbar scoliosis, fracture and prior internal fixation of the proximal femur, osteochondrosis. If patient who has a risk factor is complaining about sudden, constant pain in lower back or any other pelvic area, then pelvic insufficiency fracture needs to be considered. When pelvic insufficiency fracture is suspected the main test to be carried out is plain radiography. Monitoring plain radiography or suspecting pubic bone fracture the CT scan is recommended. Effective treatment of pelvic insufficiency fracture needs to be in conjunction with the treatment of osteoporosis and bone fracture in the pelvis.

Identification of the location of the A1 pulley combining palpation technique with palm landmarks and percutaneous release of A1 pulley with a 19-gauge needle: A cadaveric study:

The aims of this study were to identify the location of the A1 pulley combining palpation technique with superficial palm landmarks and to determine the efficacy and safety of A1 pulley percutaneous release with a 19-gauge needle. Fourteen fresh frozen cadaveric specimens were used: 56 fingers and 14 thumbs. The location of the A1 pulley was based on anatomical landmarks and was identified in all digits. Complete release of the A1 pulley occurred in 60 of the 70 digits (85.7%). The length of the A1 pulley in thumbs was 5.7 mm and in other fingers 4.5 mm. There were no signs of neurovascular bundle injuries. The mean distance between needle pathway and neurovascular bundle was 4.3 mm in the thumbs and 6.5 mm in the other fingers. There were no total flexor tendon injuries. The location of the A1 pulley can be predicted with success. Percutaneous release of the A1 pulley with a 19-gauge needle shows acceptable results in both safety and efficacy.

Biomechanical evaluation of native acromioclavicular joint ligaments and two reconstruction techniques in the presence of the sternoclavicular joint: A cadaver study:

Background: Where is over 100 reconstruction techniques described for acromioclavicular (AC) joint reconstruction. Although, it is not clear whether the presence of the sternoclavicular (SC) joint influences the biomechanical properties of native AC ligaments and reconstruction techniques. The purpose of the present study was to investigate the biomechanical properties of native AC joint ligaments and two reconstruction techniques in cadavers with the SC joint still present. Materials and Methods: We tested eight fresh-frozen cadaver hemithoraces for superior translation (70 N load) and translation increment after 1000 cycles (loading from 20 to 70 N) in a controlled laboratory study. There were three testing groups created: native ligaments, the single coracoclavicular loop (SCL) technique, and the two coracoclavicular loops (TCL) technique. Superior translation was measured after static loading. Translation increment was calculated as the difference between superior translation after cyclic and static loading. Results: Native AC ligaments showed significantly lower translation than the SCL (p = 0.023) and TCL (p = 0.046) groups. The SCL had a significantly lower translation increment than native AC ligaments (p = 0.028). There was no significant difference between reconstruction techniques in terms of translation (p = 0.865) and translation increment (p = 0.113). Conclusions: Native AC joint ligaments had better static properties than both reconstruction techniques and worse dynamic biomechanical properties than the SCL technique. The SCL technique appeared to be more secure than the TCL technique. The presence of the SC joint did not have an observable influence on test results.

Non-anatomic fixation for longstanding traumatic pubic diastasis using a bone graft: A report of two cases

The incidence of internal fixation failure of symphysis diastasis varies from 6% to 75%. Hardware breakage or migration and symphysis disruption recurrence are often asymptomatic and only in a few cases reoperation is required. This report describes the managements of two cases after failed internal fixation and neglected traumatic symphysis diastasis when it was technically impossible to achieve anatomical reduction of the anterior pelvic ring. Internal fixation and a bone graft for the symphysis without anatomical reposition were performed. Both of the patients achieved good results and had no complaints of pain during daily activities. Restoration of the anatomy should not be the aim in treating recurrence of the symphysis diastasis after failed fixation. The aim of the surgery was static fixation of the anterior pelvic ring with bone grafting.

A mini volume loading test (mVLT) using 2.5-mL kg−1 boluses of crystalloid for indication of perioperative changes in hydration status

BACKGROUND AND OBJECTIVE A mini volume loading test (mVLT) evaluating hemodilution during step-wise crystalloid infusion has established that the arterio-capillary plasma dilution difference is inversely correlated to the body hydration level of subjects. This observational study aimed to test whether this can be replicated in a perioperative setting using a 2.5-mLkg-1 boluses. MATERIALS AND METHODS The mVLT was performed before induction of regional anesthesia and 24h later. Step-wise infusion implied six mini fluid challenges. These consisted of 2.5-mLkg-1 boluses of Ringers acetate infused during 2-3min and followed by 5-min periods with no fluids. Invasive (arterial) and noninvasive (capillary) measurements of hemoglobin were performed before and after each mini fluid challenge, as well as after a 20-min period without fluid following the last bolus. Hemoglobins were used to calculate the arterio-capillary plasma dilution difference which is used as an indication of changes in body hydration level. The 24-h fluid balance was calculated. RESULTS Subjects were 69.5 (6.0) years old, their height was 1.62m (1.56-1.65), weight was 87.0kg (75.5-97.5) and body mass index (BMI) was 33.5kg/m2 (31.0-35.1). Preoperative arterio-capillary plasma dilution difference was significantly higher than postoperative (0.085 [0.012-0.141] vs. 0.006 [-0.059 to 0.101], P=0.000). The perioperative 24-h fluid balance was 1976mL (870-2545). CONCLUSIONS The mVLT using 2.5-mLkg-1 boluses of crystalloid was able to detect the higher postoperative body hydration level in total knee arthroplasty patients.

Different Stabilization Techniques for Type 62B3 Acetabular Fractures in Combination With Primary Total Hip Arthroplasty in Elderly Patients: A Biomechanical Comparison

Introduction: The total hip arthroplasty (THA) as part of acute fracture management is used for acetabular fractures in elderly patients. Our objective was to assess the stability of osteosynthesis performed using 2 different techniques in combination with THA in an experimental model. Materials and Methods: We conducted 20 experiments using the left-side hemipelves composite bone models. There were 2 testing groups: 1- and 2-stage osteosynthesis. The acetabular fractures of the anterior column and posterior hemitransverse were simulated. The same THA technique was used in both groups. The stability of osteosynthesis was explored and compared between the groups by measuring the fracture displacement of anterior and posterior columns under the standardized test load (1187 N) protocol. Load distance diagrams were generated. Results: The 0.680-mm gap (0.518; 1.548) of the posterior column in the 1-stage group (n = 10) was higher than the 0.370-mm gap (0.255; 0.428) in the 2-stage group (n = 10; P = .002). There was no significant difference between the gap of the anterior column in the 1- and 2-stage groups (0.135 [0.078; 0.290] mm vs 0.160 [0.120; 0.210] mm; P = .579). Conclusion: The 2-stage osteosynthesis of the anterior and posterior columns in combination with THA provides better stability of posterior column when compared to 1-stage method in composite bone models.