Evaluation of follow-up colonoscopy in acute colonic diverticulitis for detection of advanced adenoma and colon cancer: a retrospective cohort study.

BACKGROUND: Due to variable rates of colon carcinoma or advanced adenoma mimicking an acute diverticulitis episode, the necessity of colonoscopy to detect colon cancer or advanced adenoma remains to be explored. This study investigated the incidence and predictive factors of colon cancer or advanced adenoma following acute diverticulitis. METHODS: We evaluated retrospectively all consecutive patients with an episode of computed tomography-proven acute diverticulitis between June 2016 and August 2019. A follow-up colonoscopy was performed. Demographic and clinical parameters were recorded. Patients with clinically substantial colonic neoplasia (colon cancer or advanced adenoma) were classified as Group A, while Group B included patients without clinically significant colonic neoplasia. The incidence of clinically significant colonic neoplasia in acute diverticulitis patients was regarded as the primary outcome. RESULTS: The mean age of 233 patients with acute diverticulitis was 58.6 ± 12.7 years. Complicated diverticulitis was detected in 39 patients (16.7 %). Sixteen patients (6.9 %) were assigned to Group A and 217 patients (93.1 %) to Group B. The age of the patients in group A was significantly higher than in Group B (p =0.001). Age above 50 and 65 years was also significantly associated with clinically significant colonic neoplasia (p =0.015 and p =0.012, respectively). The other variables did not influence the development of clinically significant colonic neoplasia (p >0.05). CONCLUSIONS: Colonoscopy examination following an episode of acute diverticulitis may not be recommended for all patients due to the rare occurrence of colon cancer or clinically significant colonic neoplasia in those younger than 50 years. HIPPOKRATIA 2021, 25 (2):69-74.

Extracellular and Intracellular Fluid Shifts on the Onset of Transcutaneous Auricular Vagus Nerve Stimulation.

In this paper, we propose multifrequency body impedance measurement technique for monitoring the onset of vagus nerve stimulation. In response to transcutaneous electrical vagus stimulation, changes occur in body fluids i.e. fluid shifts in extracellular and intracellular media that can be assessed by Cole parameters Re and Ri before and after stimulus, by measuring single side impedance spectroscopy (from 3 kHz to 1 MHz) between wrist and ankle. Following a resting period of 5 minutes in supine position, auricular vagus nerve was stimulated for 3 minutes and BIS performed every 10 seconds, on 23-27 years old, 5 healthy subjects. During the stimulation phase, either an increase or a decrease was observed in extracellular and intracellular fluids. In 3 of the subjects, an ECF decrease of 0.02% per kg was compensated by 0.02 to 0.06% per kg increase in ICF; with a correlation coefficient of -0,70 to -0,79; suggesting fluid shifts between ECF and ICF. With the other 2 subjects, both ECF and ICF decreased by about 0.02% per kg. The study was performed with a limited number of participants; to reach statistically meaningful results measurements will be performed over a larger sample size.

Electrical impedance of human blood with and without anticoagulants in the ß-dispersion region.

Impedance spectroscopy of blood with and without anticoagulants (Acid Citrate Dextrose (ACD), Ethylene Diamine Tetra-acetic Acid (EDTA) and Lithium Heparin (LH)), taken from healthy donors, ages 24-33, are performed in the frequency range 100 kHz-1MHz, using the two electrode impedance measurement method. High frequency data are used in fitting the Cole plot, assuming electrode polarization effects are negligible. It is verified that this is acceptable since the characteristic frequency of the blood is around 1MHz. Cole parameters are used to evaluate the effects of anticoagulants on blood impedance. Interior resistance of red blood cells is not influenced by addition of anticoagulants, whereas plasma resistance, characteristic frequency and depression angle changed. ACD decreases plasma resistance and alpha value of blood, but increases its characteristic frequency. LH significantly increases plasma resistance, but its effect in the characteristic frequency is not clear. No significant effects of EDTA on the electrical properties of blood are detected.

Motor unit territories in juvenile myoclonic epilepsy patients.

In this study, the scanning EMG technique was implemented to investigate electrophysiological cross-sections of the motor unit (MU) territories in healthy volunteers and in subjects with juvenile myoclonic epilepsy and spinal muscular atrophy. Measurements were taken intramuscularly by means of two concentric needle electrodes from biceps brachialis muscles. 3-D maps of the MU territories were plotted for each MU to determine the lengths of MU cross-section and the maximum amplitudes of each MU. There was evidence of a preponderance of large MUs in patients with juvenile myoclonic epilepsy.

Physiological quality assessment of stored whole blood by means of electrical measurements.

The physiological parameters of blood such as extracellular Na(+), K(+), Cl(-), pH, 2,3-DPG and ATP and the complex electrical impedance were measured using whole blood samples from 31 male donors (21 donors form the training set and ten donors were used for testing), on the 0th, 10th and 21st day of blood bank storage. During storage, while the extracellular fluid resistance (R(e)) and the intracellular fluid resistance (R (i)) decreased progressively with time, the effective cell membrane capacitance (C(m)) has increased. Blood bank storage resulted in a rise in K(+) and a fall in Na(+), Cl(-), pH, 2,3-DPG and ATP. Accordingly, all electrical parameters correlated with Na(+), K(+), Cl(-), pH and ATP, at varying levels. By applying the multi-regression analysis, it was demonstrated that R (i), R (e) and especially C (m) were appropriate for the assessment of Na(+), K(+), Cl(-), pH and ATP until the 21st day of storage.

Storage effects on the Cole-Cole parameters of erythrocyte suspensions.

Chemical alterations of red blood cells (RBCs) during storage eventually affect the electrical properties of blood. In this study, the physiological parameters such as extracellular (SAGM + CPD + residual plasma) Na(+), K(+), Cl(-), pH, 2,3-DPG and ATP together with the Cole-Cole parameters were measured using erythrocyte suspensions from 51 male donors (31 donors form the training set and 20 donors are used for testing), on the 0th, 10th, 21st, 35th and 42nd days of storage. During storage, while the surrounding fluid resistance (R(e)) and the effective cell membrane capacitance (C(m)) increased progressively with time, the intracellular fluid resistance (R(i)) has decreased. Storage of RBCs resulted in a rise in K(+) and a fall in Na(+), Cl(-), pH, 2,3-DPG and ATP. Accordingly, electrical parameters were all correlated with Na(+), K(+), Cl(-), pH and ATP at varying levels. By applying multi-regression analysis, it is concluded that R(i), R(e) and C(m) are appropriate for modeling Na(+), K(+), Cl(-), pH and ATP during storage.

Digital subtraction method for transient evoked otoacoustic emission recording with ipsilateral noise suppression: an application to stimulus artifact reduction.

The suppression of transient evoked otoacoustic emissions (TEOAEs) by continuous ipsilateral noise masking was investigated to explore the feasibility of its use in the elimination of the acoustical stimulus artifact. A reference noise template was obtained by stimulating the ear with identically reproducible digitally synthesized broadband noise. The same noise was used to suppress a TEOAE generated by an ipsilaterally presented click under the same conditions. Digital subtraction of the reference noise from the noise-suppressed TEOAE resulted in obtaining a template of a click artifact for that ear. The results have shown that the digital subtraction method cancels the suppressor noise, enabling the observation of the suppressed TEOAE. The subtraction of the stimulus artifact template from the original TEOAE allowed the recovery of the emission waveform with substantially reduced stimulus artifact, thus enabling the recovery of high-frequency otoacoustic emission components.

Time-frequency distribution of evoked otoacoustic emissions.

Otoacoustic emissions (OAE) are non-stationary signals that vary in time depending on the characteristics of the stimulus. Traditional spectral analysis using Fourier methods ignores the effects of time and can miss important temporal information. Therefore, a better form of spectral analysis requires the use of time-frequency distribution methods. Traditionally, short time Fourier transforms (STFT), commonly known as spectrograms, are used to provide such time-frequency representations. STFT however, suffer from poor resolution and do not provide enough detail about the characteristics of the emissions. In this study, recently developed time-frequency distributions, the Wigner Distribution (WD) and the Choi-Williams Distribution (CWD) are investigated to provide high resolution representations of transient evoked OAEs. Although WD has excellent properties for time-frequency analysis, it suffers from cross-term artefacts generated when multiple sinusoids are present. CWD provides a solution to this problem at the expense of poor time and frequency support. In this study, we use both distributions to estimate the cross-products and provide a relatively artefact-free time-frequency distribution of OAEs. This method is applied to both click and tone burst evoked OAE and shows a more detailed time-frequency representation with as many crests and valleys as different latencies.