Factors associated with clinical outcome in geriatric acute cholangitis patients.

OBJECTIVE: We aimed to determine the risk factors associated with the clinical outcome in cases of acute cholangitis among the geriatric age group. PATIENTS AND METHODS: Patients aged >65 years hospitalized with the diagnosis of acute cholangitis in an emergency internal medicine clinic were included in this study. RESULTS: The study population comprised 300 patients. In the oldest-old group, the rates of severe acute cholangitis and intensive care unit hospitalization (39.1% vs. 23.2%, p<0.001) were higher. The mortality rate was also higher in the oldest-old group (10.4% vs. 5.9%, p=0.045). The presence of malignancy, ICU hospitalization, decreased platelet levels, decreased hemoglobin levels, and decreased albumin levels were associated with mortality. In the multivariable regression model in which variables associated with Tokyo severity were included, the associated factors for membership in the severe risk group compared to the moderate risk group were decreased platelet count (OR: 0.96; p=0.040) and decreased albumin level (OR: 0.93; p=0.027). Increasing age (OR: 1.07; p=0.001), malignancy etiology (OR: 5.03; p<0.001), increasing Tokyo severity (OR: 7.61; p<0.001), and decreasing lymphocyte count (OR: 0.49; p=0.032) were determined to be associated with ICU admission. Decreasing albumin levels (OR: 0.86; p=0.021) and ICU admission (OR: 16.43; p=0.008) were determined to be factors associated with mortality. CONCLUSIONS: Worse clinical outcomes occur among geriatric patients with increasing age.

The role of triglyceride-glucose index in determining subclinical atherosclerosis in patients with primary hypertension.

OBJECTIVE: With the current study, we aimed at examining the relationship between the triglyceride-glucose (TyG) index and subclinical atherosclerosis in patients with primary hypertension. PATIENTS AND METHODS: 185 patients with primary hypertension were included in this study. The following findings were considered to be associated with target organ damage (TOD): urinary protein excretion > 150 mg/dL and microalbumin excretion > 30 mg/dL, carotid intima-media thickness (CIMT) ≥ 0.9 mm or carotid plaque and/or left ventricular mass index (LVMI) > 95 g/m2 in women, > 115 g/m2 in men. RESULTS: TyG index values were positively correlated with levels of CIMT (r=0.434; p<0.001), LVMI (r=0.351; p<0.001), microalbuminuria (r=0.347; p<0.001), and proteinuria (r=0.355; p<0.001). In the multivariable regression model, in which the variables associated with the presence of TOD were included, increased age (OR: 1.04, p=0.025), increased body mass index (OR: 1.10, p=0.042), and increased TyG index value (OR: 1.05, p<0.001) had independent associations with TOD. The threshold value of the TyG index for the presence of TOD was determined as > 8.85 with 79.0% sensitivity and 77.1% specificity (AUC±SE: 0.859±0.03, +PV: 70.6%, -PV: 84.0%, p<0.001). The TyG index had a superior diagnostic discrimination compared to its components in predicting the presence of TOD. CONCLUSIONS: Increased TyG index values in patients with primary hypertension are associated with damage to target organs, not merely subclinical atherosclerosis.

Nasal secretory protein changes following intravenous choline administration in calves with experimentally induced endotoxaemia.

Nasal secretory fluid proteomes (NSPs) can provide valuable information about the physiopathology and prognosis of respiratory tract diseases. This study aimed to determine changes in NSP by using proteomics in calves treated with lipopolysaccharide (LPS) or LPS + choline. Healthy calves (n = 10) were treated with LPS (2 µg/kg/iv). Five minutes after LPS injection, the calves received a second iv injection with saline (n = 5, LPS + saline group) or saline containing 1 mg/kg choline (n = 5, LPS + choline group). Nasal secretions were collected before (baseline), at 1 h and 24 h after the treatments and analysed using label-free liquid chromatography-tandem mass spectrometry (LCMS/MS). Differentially expressed proteins (>1.2-fold-change) were identified at the different time points in each group. A total of 52 proteins were up- and 46 were downregulated at 1 h and 24 h in the LPS + saline group. The upregulated proteins that showed the highest changes after LPS administration were small ubiquitin-related modifier-3 (SUMO3) and glutathione peroxidase-1 (GPX1), whereas the most downregulated protein was E3 ubiquitin-protein ligase (TRIM17). Treatment with choline reduced the number of upregulated (32 proteins) and downregulated proteins (33 proteins) in the NSPs induced by LPS. It can be concluded that the proteome composition of nasal fluid in calves changes after LPS, reflecting different pathways, such as the activation of the immunological response, oxidative stress, ubiquitin pathway, and SUMOylation. Choline treatment alters the NSP response to LPS.

Digitizing clinical trials.

Clinical trials are a fundamental tool used to evaluate the efficacy and safety of new drugs and medical devices and other health system interventions. The traditional clinical trials system acts as a quality funnel for the development and implementation of new drugs, devices and health system interventions. The concept of a "digital clinical trial" involves leveraging digital technology to improve participant access, engagement, trial-related measurements, and/or interventions, enable concealed randomized intervention allocation, and has the potential to transform clinical trials and to lower their cost. In April 2019, the US National Institutes of Health (NIH) and the National Science Foundation (NSF) held a workshop bringing together experts in clinical trials, digital technology, and digital analytics to discuss strategies to implement the use of digital technologies in clinical trials while considering potential challenges. This position paper builds on this workshop to describe the current state of the art for digital clinical trials including (1) defining and outlining the composition and elements of digital trials; (2) describing recruitment and retention using digital technology; (3) outlining data collection elements including mobile health, wearable technologies, application programming interfaces (APIs), digital transmission of data, and consideration of regulatory oversight and guidance for data security, privacy, and remotely provided informed consent; (4) elucidating digital analytics and data science approaches leveraging artificial intelligence and machine learning algorithms; and (5) setting future priorities and strategies that should be addressed to successfully harness digital methods and the myriad benefits of such technologies for clinical research.

Serum choline and butyrylcholinesterase changes in response to endotoxin in calves receiving intravenous choline administration.

Endotoxemia treatment options are still of interest due to high mortality and choline treatment is one of them because of its role in the cholinergic anti-inflammatory pathway. This study investigated serum choline and butyrylcholinesterase (BChE) responses, and their correlations with inflammatory, oxidative stress and tissue damage biomarkers, including paraoxanase-1 (PON1), and clinical signs in calves with endotoxemia and the effect of choline treatment in these responses. Healthy calves (n = 20) were divided equally into 4 groups: Control (0.9% NaCl, iv), Choline (C; 1 mg/kg/iv,once), Lipopolysaccharide (LPS; 2 µg/kg/iv,once) and LPS + C. Clinical and laboratory examinations were performed before and 0.5-48 h (hrs) after treatments. Following LPS administration, serum choline level increased at 0.5-24 h (P < .01), whereas serum BChE and PON1 level decreased at 48 h (P < .01) compared to their baselines. In LPS + C group, the increase in serum choline level was significantly higher (P < .01) than that of C and LPS groups. LPS did not decrease serum BChE levels significantly in calves treated with choline. Serum choline and BChE results correlated negatively with white blood cell count and positively (P < .001) with PON1 levels, oxidative stress index, inflammation and hepato-muscular injury markers. In conclusion serum choline and BChE may have a role in the pathophysiology of endotoxemia in calves. High serum choline concentration is associated with an improvement in response to LPS administration in calves treated with choline, probably by preventing the imbalances between oxidative stress and anti-oxidant capacity, preventing the serum BChE and PON1 decreases, and inhibition/attenuation of acute phase reaction and hepato-muscular injury in calves with endotoxemia.

Changes in serum proteins after endotoxin administration in healthy and choline-treated calves.

BACKGROUND: This study aimed to investigate the possible serum protein changes after endotoxin administration in healthy and choline-treated calves using proteomics. These results are expected to contribute to the understanding of the pathophysiological mechanisms of endotoxemia and the beneficial effect of choline administration in this clinical situation. METHODS: Healthy-calves (n = 20) were divided into 4 groups: Control, Choline treated (C), Lipopolysaccharide administered (LPS), and LPS + C. Control calves received 0.9 % NaCl injection. Calves in C and LPS + C groups received choline chloride (1 mg/kg/iv). Endotoxin (LPS) was injected (2 µg/kg/iv) to the calves in LPS and LPS + C groups. Serum samples were collected before and after the treatments. Differentially expressed proteins (> 1.5 fold-change relative to controls) were identified by LC-MS/MS. RESULTS: After LPS administration, 14 proteins increased, and 13 proteins decreased within 48 h as compared to controls. In the LPS group, there were significant increases in serum levels of ragulator complex protein (189-fold) and galectin-3-binding protein (10-fold), but transcription factor MafF and corticosteroid binding globulin were down regulated (≥ 5 fold). As compared with the LPS group, in LPS + C group, fibrinogen gamma-B-chain and antithrombin were up-regulated, while hemopexin and histone H4 were down-regulated. Choline treatment attenuated actin alpha cardiac muscle-1 overexpression after LPS. CONCLUSIONS: LPS administration produces changes in serum proteins associated with lipid metabolism, immune and inflammatory response, protein binding/transport, cell adhesion, venous thrombosis, cardiac contractility and blood coagulation. The administration of choline is associated with changes in proteins which can be related with its beneficial effect in this clinical situation.

Echocardiography as an indication of continuous-time cardiac quiescence.

Cardiac computed tomography (CT) angiography using prospective gating requires that data be acquired during intervals of minimal cardiac motion to obtain diagnostic images of the coronary vessels free of motion artifacts. This work is intended to assess B-mode echocardiography as a continuous-time indication of these quiescent periods to determine if echocardiography can be used as a cost-efficient, non-ionizing modality to develop new prospective gating techniques for cardiac CT. These new prospective gating approaches will not be based on echocardiography itself but on CT-compatible modalities derived from the mechanics of the heart (e.g. seismocardiography and impedance cardiography), unlike the current standard electrocardiogram. To this end, echocardiography and retrospectively-gated CT data were obtained from ten patients with varied cardiac conditions. CT reconstructions were made throughout the cardiac cycle. Motion of the interventricular septum (IVS) was calculated from both echocardiography and CT reconstructions using correlation-based, deviation techniques. The IVS was chosen because it (1) is visible in echocardiography images, whereas the coronary vessels generally are not, and (2) has been shown to be a suitable indicator of cardiac quiescence. Quiescent phases were calculated as the minima of IVS motion and CT volumes were reconstructed for these phases. The diagnostic quality of the CT reconstructions from phases calculated from echocardiography and CT data was graded on a four-point Likert scale by a board-certified radiologist fellowship-trained in cardiothoracic radiology. Using a Wilcoxon signed-rank test, no significant difference in the diagnostic quality of the coronary vessels was found between CT volumes reconstructed from echocardiography- and CT-selected phases. Additionally, there was a correlation of 0.956 between the echocardiography- and CT-selected phases. This initial work suggests that B-mode echocardiography can be used as a tool to develop CT-compatible gating techniques based on modalities derived from cardiac mechanics rather than relying on the ECG alone.

Subclinical hypothyroidism in combination with vitamin D deficiency increases the risk of impaired left ventricular diastolic function.

OBJECTIVE: Subclinical hypothyroidism and vitamin D deficiency are common. The diastolic function of patients with both subclinical hypothyroidism and vitamin D deficiency remains unknown. This study aimed to investigate diastolic dysfunction in patients with both subclinical hypothyroidism and vitamin D deficiency. SUBJECTS AND METHODS: This study included 254 patients. All patients underwent standard Doppler echocardiography. Patients who had risk factors for diastolic dysfunction or had used L-thyroxine and vitamin D within the previous 3 months were excluded. Vitamin D deficiency was defined as a 25-OH-vitamin D level lower than 20 ng/ml, and vitamin D sufficiency was defined as a 25-OH-vitamin D level ≥ 30 ng/ml. Subclinical hypothyroidism was defined as a TSH level of 4.5-10 mU/l when the free T4 concentration was normal. RESULTS: The patients were divided into 4 groups. Group 1 (n=71) included patients with subclinical hypothyroidism and vitamin D deficiency; Group 2 (n=66) included patients with subclinical hypothyroidism and vitamin D sufficiency; Group 3 (n=65) included euthyroid patients with vitamin D deficiency; and Group 4 (n=52) included euthyroid patients with vitamin D sufficiency. LAVI (31.3 ± 3.2, 28.7 ± 3.0, 28.4 ± 3.4, and 27.9 ± 3.9; p<0.001) and E/E' values (11.2 ± 2.7, 8.9 ± 2.7, 9.1 ± 2.9, 8.8 ± 2.5; p<0.001) were significantly higher in Group 1 than in Groups 2, 3 and 4. E' values were significantly lower in Group 1 than in Groups 2, 3 and 4. CONCLUSION: The coexistence of subclinical hypothyroidism with vitamin D deficiency can lead to further deterioration in the LV diastolic function via the regulation of intracellular calcium and induction of inflammatory activity. Therefore, close follow-up of the diastolic functions of these patients could be beneficial.

Increased serum levels of GDF-15 associated with mortality and subclinical atherosclerosis in patients on maintenance hemodialysis.

BACKGROUND/AIMS: Increased carotid intima-media thickness (CIMT) was shown to be an independent predictor of cardiovascular (CV) mortality in dialysis patients and the general population. Growth differentiation factor 15 (GDF-15), a member of the transforming growth factor superfamily, is produced by cardiomyocytes and atherosclerotic lesions under stress conditions such as inflammation. We assessed associations between serum concentrations of GDF-15, mortality, and CIMT for subclinical atherosclerosis in hemodialysis (HD) patients. METHODS: A total of 87 patients on maintenance hemodialysis and 45 sex- and age-matched healthy controls were included in this prospective study. Serum GDF-15 levels were measured by ELISA. CIMT was assessed by Doppler ultrasonography. The association between serum GDF-15 levels and mortality was assessed using Cox regression analysis with serum levels categorized into two groups according to the median value (328.18 pg/ml). Patients were followed for 2 years and cause-specific and all-cause mortality were determined. RESULTS: The median level of serum GDF-15 was significantly higher in HD patients than controls [328 (198-522) vs. 176 (101-289) pg/ml, p < 0.01, respectively]. Serum GDF-15 levels were correlated to CIMT (r = 0.607, p < 0.001), C-reactive protein (CRP; r = 0.250, p = 0.010), HD duration (r = 0.376, p = 0.004), and serum albumin (r = - 0.156, p = 0.030). The multivariate analysis revealed that GDF-15 was found to be an independent variable of CIMT in HD patients. In the study, the serum GDF-15 level was an independent marker of all-cause of mortality when adjusted for age, CRP, and history of diabetes mellitus. CONCLUSION: The relationship between serum GDF-15, mortality, and carotid artery thickening suggests that GDF-15 may be a novel marker of atherosclerosis, inflammation, and malnutrition in HD patients.

Monitoring bone morphogenetic protein-2 and -7, soluble receptor activator of nuclear factor-κB ligand and osteoprotegerin levels in the peri-implant sulcular fluid during the osseointegration of hydrophilic-modified sandblasted acid-etched and sandblasted acid-etched surface dental implants.

BACKGROUND AND OBJECTIVE: The implant surface plays a major role in the biological response to titanium dental implants. The aim of this study was to investigate levels of soluble receptor activator of nuclear factor-κB ligand (sRANKL), osteoprotegerin (OPG), bone morphogenetic protein-2 (BMP-2) and -7 (BMP-7) in the peri-implant crevicular fluid (PICF) of different implants during the osseointegration period. MATERIAL AND METHODS: Forty-seven patients (22 females and 25 males, mean age 47.34 ± 10.11) were included in this study. Forty-seven implants from two implant systems (group A1 (sandblasted acid-etched [SLA]-16), group A2 (hydrophilic-modified SLA [SLActive]-16), and group B (sandblasted acid-etched [SLA]-15) were placed using standard surgical protocols. PICF samples, plaque index, gingival index and probing depth measurements were obtained at 1 and 3 mo after surgery. PICF levels of sRANKL, OPG, BMP-2/-7 were analyzed by ELISA. RESULTS: No complications were observed during the healing period. No significant differences were observed in the PICF levels of sRANKL, OPG, BMP-2 and BMP-7 for all groups at any time point (p > 0.05). A significant decrease was observed in BMP-2 levels in group A1 (p < 0.05). A significant increase in BMP-7 levels was observed only for group A2 (p < 0.05). There was a strong negative correlation between OPG and gingival index and a negative correlation between BMP-7 and plaque index (p < 0.05). CONCLUSION: Considering the correlations between clinical and biochemical parameters, the levels of these cytokines in PICF during early healing of implants reflects the degree of peri-implant inflammation, rather than differences in the implant surfaces.

Increased levels of galectin-3 were associated with prediabetes and diabetes: new risk factor?

PURPOSE: Galectin-3 (Gal-3) is a marker of cardiac fibrosis and predicts incident heart failure. Gal-3-deficient mice are resistant to multiple low-dose streptozotocin-induced diabetes. Recent experimental studies suggested an important role for Gal-3 in the regulation of adiposity, metaflammation and type 2 diabetes. This study aimed to examine the relationship between Gal-3 and newly diagnosed prediabetes and diabetes. METHODS: Gal-3 concentrations were measured in 118 participants and 56 age- and sex-matched healthy controls. All subjects underwent a 75-g oral glucose tolerance test and were stratified into normal, prediabetic, and diabetes mellitus subgroups. DM was defined as a plasma glucose level ≥126 mg/dL in the fasting state or ≥200 mg/dL in the second hour after glucose loading. Impaired fasting glucose was defined as an FPG level of 100-125 mg/dL, and impaired glucose tolerance was defined as a 2-h plasma glucose level of 140-199 mg/dL. RESULTS: Sixty-one patients had prediabetes (Group 1), 57 had diabetes (Group 2), and 56 had neither diabetes nor prediabetes (Group 3). Gal-3 levels correlated with FPG (r = 0.787, P < 0.01), 2hPG (r = 0.833, P < 0.01), CRP (r = 0.501, P < 0.01), and HOMA-IR (r = 0.518, P < 0.01). Gal-3 levels were higher in Group 2 than in Groups 1 and 3 [1,053.9 (358.1) and 744.1 (119.3) vs. 481.7 (175.4) pg/mL; P < 0.001]. Gal-3 is an independent predictor of diabetes in multivariate logistic analysis. In ROC analysis, a Gal-3 cutoff value of 803.55 pg/mL diagnoses diabetes with a sensitivity of 80.7 % and a specificity of 85.5 % (AUC = 0.912). CONCLUSIONS: Gal-3 is a promising biomarker for detecting prediabetes and diabetes.

Neutrophil-lymphocyte ratio may be superior to C-reactive protein for predicting the occurrence of postmenopausal osteoporosis.

OBJECTIVE: Recent studies revealed that inflammation plays a critical role in bone remodeling and the pathogenesis of postmenopausal osteoporosis, a major health concern. Neutrophil-lymphocyte ratio (NLR) is a cost-effective marker of inflammation that has been linked with several diseases. This study aimed to compare NLR and C-reactive protein (CRP) levels in osteopenic, osteoporotic, and control subjects and to assess the correlation between NLR levels, CRP, and bone mineral density (BMD) in postmenopausal women. METHODS: In this cross-sectional study, the relationship between NLR, CRP, and BMD in 438 women was investigated using uni- and multivariate analyses. BMD (g/cm²) was measured by dual-energy X-ray absorptiometry (DEXA) at the lumbar spine and femur. Complete blood count (CBC), CRP, glucose/lipid metabolism, and established risk factors were determined. RESULTS: In the osteoporotic group, NLR and CRP levels were found to be elevated as compared to the osteopenic and control groups (NLR: 4.68 ± 0.72, 3.17 ± 0.43, 2.01 ± 0.54; CRP: 12.3 ± 4.1, 4.1 ± 2.7, 3.2 ± 2.1, respectively). A negative correlation was present between NLR and the lumbar spine (L2-L4) and femoral neck BMD after adjusting other risk factors. There was no correlation between CRP levels and BMD after adjusting other risk factors. NLR was significantly associated with L2-L4 BMD (ß = -0.653, p<0.001) and femoral neck BMD (ß = -0.178, p<0.001), but CRP level had no association with BMD in a multivariate model. CONCLUSIONS: Our data indicate that NLR may be a better predictor than CRP for occurrence of osteoporosis in postmenopausal women.

Benefits of the neutrophil-to-lymphocyte ratio for the prediction of gestational diabetes mellitus in pregnant women.

AIMS: There is growing consensus in the literature that inflammation plays a central role in the pathophysiology of obesity, Type 2 Diabetes Mellitus (T2DM), Gestational Diabetes Mellitus (GDM) and cardiovascular complications. Measuring the neutrophil-to-lymphocyte ratio (NLR) provides a simple inexpensive method for the assessment of inflammatory status. We investigated the predictive value of pre-procedural (before the oral glucose tolerance test (OGTT)) NLR on the development of GDM in pregnancy. METHODS: 42 women with GDM and 68 women without GDM were included in the study. Complete Blood Count and biochemical tests were followed by a diagnostic 4-point 100-g-OGTT within 2 weeks. GDM was diagnosed by the Carpenter and Coustan criteria. The NLR was calculated from the data. RESULTS: The mean NLR level was significantly higher in GDM women (3.00±0.83 vs. 2.26±0.43 p<0.001, respectively). In ROC analysis, NLR>2.93 had 76.2% sensitivity and 94.1% specificity in predicting GDM. Logistic regression analysis showed that elevated NLR (OR: 5.512, 95% CI: 1.352-22.475, p=0.017) was an independent variable for predicting GDM in pregnancy. CONCLUSIONS: An elevated NLR level is a powerful and independent predictor of GDM. The results of this study suggested that inflammation plays a central role in the pathogenesis of GDM.

Does pantoprazole protect against reperfusion injury following myocardial ischemia in rats?

BACKGROUND: Myocardial ischemia is inadequate perfusion due to reduced blood flow. Sudden onset of reperfusion could result with damage to the myocytes that have not been affected during ischemia called ischemia reperfusion (I/R) injury. Extracellular accumulation of H+ ions resulting in tissue acidosis is one of the underlying mechanisms. Inhibition of myocardial H+/K+-ATPase, namely proton pump, may lead to intracellular acidification via decreasing the extracellular H+ transport. AIM: The aim of this study is to investigate the effects of a proton pump inhibitor pantoprazole in intact rat I/R models. MATERIALS AND METHODS: A total of 30 adult male Wistar albino rats weighing 200-300 g were studied. Rats were allocated into four groups: sham (n=6), ischemia (n=8), control (n=8), and pantoprazole (n=8). Left anterior descending coronary artery was occluded for 30 minutes and then reperfused for two hours. Pantoprazole was administered via jugular vein at the dose of 9 mg/kg starting from 30 minutes before ischemia, to the first 30 minutes of reperfusion. Haemodynamic parameters were recorded and serum CK-MB levels were measured. After reperfusion, heart was removed for the measurement of myocardial infarct size. Myocardial infarct area was measured using triphenyltetrazolium chloride (TTC) staining technique. Myocardial infarction size were expressed as the percentage of the total left ventricular weight. RESULTS: Compared with other groups, plasma concentrations of CK-MB at the end of ischemia and reperfusion and myocardial infarct size were significantly lower in pantoprazole group (p < 0.008). CONCLUSIONS: Pantoprazole preconditioning induces delayed cardioprotection in intact rat I/R model, which may be triggered via H+/K+-ATPase ion channels.

Noninvasive measurement of physiological signals on a modified home bathroom scale.

A commercial bathroom scale with both handlebar and footpad electrodes was modified to enable measurement of four physiological signals: the ballistocardiogram (BCG), electrocardiogram (ECG), lower body impedance plethysmogram (IPG), and lower body electromyogram (EMG). The BCG, which describes the reaction of the body to cardiac ejection of blood, was measured using the strain gauges in the scale. The ECG was detected using handlebar electrodes with a two-electrode amplifier. For the lower body IPG, the two electrodes under the subject's toes were driven with an ac current stimulus, and the resulting differential voltage across the heels was measured and demodulated synchronously with the source. The voltage signal from the same two footpad electrodes under the heels was passed through a passive low-pass filter network into another amplifier, and the output was the lower body EMG signal. The signals were measured from nine healthy subjects, and the average signal-to-noise ratio (SNR) while the subjects were standing still was estimated for the four signals as follows: BCG, 7.6 dB; ECG, 15.8 dB; IPG, 10.7 dB. During periods of motion, the decrease in SNR for the BCG signal was found to be correlated to the increase in rms power for the lower body EMG (r = 0.89, p <; 0.01). The EMG could, thus, be used to flag noise-corrupted segments of the BCG, increasing the measurement robustness. This setup could be used for monitoring the cardiovascular health of patients at home.

A low-noise ac-bridge amplifier for ballistocardiogram measurement on an electronic weighing scale.

Ballistocardiography is a non-invasive technique for evaluating cardiovascular health. This note presents an ac-bridge amplifier for low-noise ballistocardiogram (BCG) recording from a modified weighing scale. The strain gauges in a commercial scale were excited by an ac source-square or sine wave-and the differential output voltage resulting from the BCG was amplified and demodulated synchronously with the excitation waveform. A standard BCG amplifier, with a simple dc-bridge excitation, was also built and the performance was compared to both the square- and sine-wave excited ac-bridge amplifiers. The total input-referred voltage noise (rms) integrated over the relevant BCG bandwidth of 0.3-10 Hz was found to be 30 nV (square wave source) or 25 nV (sine-wave source) for the ac-bridge amplifier and 52 nV for the standard amplifier: an improvement of 4.8 dB or 6 dB, respectively. These correspond to input-referred force noise (rms) values of 5 mN, 4 mN and 8.3 mN. The improvement in SNR was also observed in recorded waveforms from a seated subject whose BCG signal was measured with both dc- and ac-bridge circuits.

An 11 µ w, two-electrode transimpedance biosignal amplifier with active current feedback stabilization.

A novel two-electrode biosignal amplifier circuit is demonstrated by using a composite transimpedance amplifier input stage with active current feedback. Micropower, low gain-bandwidth product operational amplifiers can be used, leading to the lowest reported overall power consumption in the literature for a design implemented with off-the-shelf commercial integrated circuits (11 µW). Active current feedback forces the common-mode input voltage to stay within the supply rails, reducing baseline drift and amplifier saturation problems that can be present in two-electrode systems. The bandwidth of the amplifier extends from 0.05-200 Hz and the midband voltage gain (assuming an electrode-to-skin resistance of 100 kΩ) is 48 dB. The measured output noise level is 1.2 mV pp, corresponding to a voltage signal-to-noise ratio approaching 50 dB for a typical electrocardiogram (ECG) level input of 1 mVpp. Recordings were taken from a subject by using the proposed two-electrode circuit and, simultaneously, a three-electrode standard ECG circuit. The residual of the normalized ensemble averages for both measurements was computed, and the power of this residual was 0.54% of the power of the standard ECG measurement output. While this paper primarily focuses on ECG applications, the circuit can also be used for amplifying other biosignals, such as the electroencephalogram.

Non-invasive cardiac output trending during exercise recovery on a bathroom-scale-based ballistocardiograph.

Cardiac ejection of blood into the aorta generates a reaction force on the body that can be measured externally via the ballistocardiogram (BCG). In this study, a commercial bathroom scale was modified to measure the BCGs of nine healthy subjects recovering from treadmill exercise. During the recovery, Doppler echocardiogram signals were obtained simultaneously from the left ventricular outflow tract of the heart. The percentage changes in root-mean-square (RMS) power of the BCG were strongly correlated with the percentage changes in cardiac output measured by Doppler echocardiography (R(2) = 0.85, n = 275 data points). The correlation coefficients for individually analyzed data ranged from 0.79 to 0.96. Using Bland-Altman methods for assessing agreement, the mean bias was found to be -0.5% (+/-24%) in estimating the percentage changes in cardiac output. In contrast to other non-invasive methods for trending cardiac output, the unobtrusive procedure presented here uses inexpensive equipment and could be performed without the aid of a medical professional.

Robust ballistocardiogram acquisition for home monitoring.

The ballistocardiogram (BCG) measures the reaction of the body to cardiac ejection forces, and is an effective, non-invasive means of evaluating cardiovascular function. A simple, robust method is presented for acquiring high-quality, repeatable BCG signals from a modified, commercially available scale. The measured BCG waveforms for all subjects qualitatively matched values in the existing literature and physiologic expectations in terms of timing and IJ amplitude. Additionally, the BCG IJ amplitude was shown to be correlated with diastolic filling time for a subject with premature atrial contractions, demonstrating the sensitivity of the apparatus to beat-by-beat hemodynamic changes. The signal-to-noise ratio (SNR) of the BCG was estimated using two methods, and the average SNR over all subjects was greater than 12 for both estimates. The BCG measurement was shown to be repeatable over 50 recordings taken from the same subject over a three week period. This approach could allow patients at home to monitor trends in cardiovascular health.

Implant-supported overdenture therapy: a 3- to 8-year prospective study.

Inflammatory changes in periimplant soft tissues and loss of alveolar bone can develop as in periodontal diseases. This clinical phenomena has been described as periimplantitis. Microorganisms such as Gram-negative anaerobic rods, spirochetes, and bacteroides that are seen in subgingival flora in periodontitis have also been found in sulcular microflora in periimplantitis. The purpose of this study was to evaluate periimplant tissue changes in totally edentulous patients who had implant-supported overdentures for 3 to 8 years (5-5.5 years) clinically from both a subjective and an objective point of view. The clinical parameters used in this study can be helpful in the evaluation of periimplant tissue health.