scholarly journals Spectral Transmission of Porcine Crystalline Lens at Post-Mortem Interval

2020 ◽  
Vol 22 (1) ◽  
pp. 35-43
Author(s):  
Oluwasola M. Ojo ◽  
Olajire B. Ajayi ◽  
Mutali J. Musa
Keyword(s):  
Crystalline Lens ◽  
Forensic Evaluation ◽  
Time Interval ◽  
Post Mortem ◽  
Spectral Transmission ◽  
Strong Negative Correlation ◽  
Post Mortem Interval ◽  
Benin City ◽  
Significant Difference ◽  
Porcine Eyes

Purpose: Determining the total spectral transmission of the porcine crystalline lens at various post mortem intervals. Method: An experimental study conducted in the Department of chemical Pharmacology, Faculty of pharmacy, University of Benin. Twenty pairs of porcine eyes were obtained from an abattoir in Benin City. The crystalline lenses were carefully extracted from the enucleated porcine eyes at various post- mortem intervals (0, 12, 24, 36 and 48hours) and their spectral transmissions were measured using a T80 UV-VIS Spectrophotometer. Measurement at 0 hour was used as a control being the baseline. Result: The result showed a strong negative correlation between increased post mortem intervals and transmission of the crystalline lens for both eyes, as the post-mortem time interval increases, the transmission of long wavelengths (r = -0.992, P = 0.001), mid wavelengths (r = -0.994, P = 0.000)  and short wavelengths(r = -0.991, P = 0.001) decreases significantly. It was also observed there was no significant difference (P> 0.05) existed  between both eyes in the different wavelength regions with increased post mortem interval. Conclusion: The study shows that time after death has effect on the spectral transmission of crystalline lens which can serve as important information in forensic evaluation. Key words: Post mortem interval, crystalline lens, spectral transmission, spectrophotometer and porcine.

scholarly journals APPROACHES TO DETERMINING POST-MORTEM INTERVAL

2020 ◽  
Vol 22 (2) ◽  
Author(s):  
V. Olkhovsky ◽  
E. Grygorian ◽  
M. Myroshnychenko
Keyword(s):  
Postmortem Interval ◽  
Biochemical Changes ◽  
Postmortem Changes ◽  
Time Interval ◽  
Post Mortem ◽  
Post Mortem Interval ◽  
Laser Polarimetry ◽  
Scientific Papers ◽  
Temperature Exposure ◽  
Medical Examiners

The main approaches and problems that arise when evaluating postmortem interval are defined, ways to avoid such problems are suggested. According to the results of scientific papers analysis on that topic, it was established that in the context of post-mortem changes studies such changes developed differently during a specific period of time passed from the time of death, they also appeared in a variety of forms as a result of environmental factors influence. The factors having a significant impact on postmortem changes were specified. A review of modern methods for determining post-mortem interval was conducted and methods for further improvement of the assessment of postmortem interval were proposed. The use of methods for assessing the PMI by means of the cadaveric phenomena does not always provide for investigating authorities necessary information due to the relatively large time interval in methods based on such changes. Researchers also note the presence of certain shortcomings in the use of existing methods. Current research using laser polarimetry methods have made it possible to establish post-mortem interval with relatively high accuracy. However, high prices and limited availability of equipment used in laser polarimetry methods preclude from using them in everyday practice of forensic medical examiners. When conducting studies on histological and biochemical changes in tissues of internal organs, certain morphological (decrease in optical density) and biochemical (changes in the levels of biochemical markers) changes in the early post-mortal period were identified, which will enable the development of specific tables where such changes would be linked to a specific post-mortem time period during certain short periods of time. Although changes in the conducted research were recognized only in the early post-mortem period and only in muscle tissue, further research on other tissues that are more resistant to post-mortem changes are likely to provide results that would be less affected by ambient temperature, exposure of a corpse to the sun rays, amount of clothing on a corpse, etc.) and also would be more accurate than most existing methods.

Ultrasound shear-wave elastography applicability in estimation of post-mortem time

Ultrasound ◽  
2021 ◽  
pp. 1742271X2110358
Author(s):  
Mohsen Mosadegh ◽  
Mehdi Khazaei ◽  
Zohreh D Abdollahpour ◽  
Sam Alahyari ◽  
Yashar Moharamzad ◽  
...  
Keyword(s):  
Shear Wave ◽  
Reference Method ◽  
Shear Wave Elastography ◽  
Time Of Death ◽  
Post Mortem ◽  
Post Mortem Interval ◽  
Significant Difference ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

Introduction Post-mortem rigidity of the tissues is one of the basic principles in forensic medicine to estimate the time of death. Qualitative methods to determine the stiffness of the corpse may have some limitations. Methods that provide quantitative values may be useful. We intended to evaluate the applicability of ultrasound shear-wave elastography of the tissues to estimate the post-mortem interval (PMI). Methods For 80 corpses, shear-wave elastography of the liver, sartorius muscle, testis, thyroid and parotid was performed before autopsy. Based on the forensic reports as the reference method to define post-mortem interval, the corpses were divided into four groups: group 0 (PMI < 24 hours), group 1 (PMI ≥24 hours and <48 hours), group 2 (PMI ≥ 48 hours and <72 hours), and group 3 (PMI ≥ 72 hours). There were 24, 38, 13, and 5 corpses, respectively, in groups 0, 1, 2, and 3. Results A significant rise in the elasticity values in comparison to elasticity of normal tissues in live adults was seen very early in the post-mortem period. Between-group comparisons showed that a significant difference in the liver elasticity was present among the groups. The mean (SD) liver elasticity was 10.29 (±0.83) in group 0, 14.98 (±1.56) in group 1, 12.49 (±1.09) in group 2, and 15.64 (±1.68) kilopascals (kPa) in group 3 ( P = 0.035). Nevertheless, elasticity measurements in other tissues were not helpful in distinguishing post-mortem interval groups. Conclusion It is possible to use liver quantitative shear-wave elastography to estimate the time of death.

scholarly journals COMPARATIVE ANALYSIS OF LASER POLARIMETRY METHODS OF POLYCRYSTALLINE FILMS OF CEREBROSPINAL FLUID FOR POST-MORTEM INTERVAL ESTIMATION

2019 ◽  
Vol 7 ◽  
Author(s):  
Marta Garazdiuk ◽  
Viktor Bachynskіy ◽  
Oleh Vanchuliak ◽  
Oleksandr Garazdiuk ◽  
Yuliya Sarkisova
Keyword(s):  
Cerebrospinal Fluid ◽  
Interval Estimation ◽  
Accurate Estimation ◽  
Time Interval ◽  
Two Dimensional ◽  
Post Mortem ◽  
Polycrystalline Films ◽  
Technological Support ◽  
Post Mortem Interval ◽  
Stokes Polarimetry

Obtaining the most accurate information about an object during its evaluation is one of the most urgent tasks of current forensic medical examination. That is why the application of new technologies in forensic medical expertise becomes an integral part of the technological support of forensic examination institutions. Purpose: To compare the effectiveness of cerebrospinal fluid polycrystalline films, microscopic images, two-dimensional Stokes-polarimetry, and autofluorescent polarimetry in post-mortem interval estimation over long- and short-term time intervals. Material and methods. The object of the study is cerebrospinal fluid donated from 70 corpses (experimental group) and 20 living persons (control group). Methods used: two-dimensional Stokes-polarimetry, autofluorescent polarimetry. Results: Quantitative characteristics of the cerebrospinal fluid’s polycrystalline films statistical moments allows us to establish relations between them and the duration of the post-mortem interval at a significant time interval. However, this method does not consider the morphology of the film of the cerebrospinal fluid and its coordinate structure. In contrast to this method, fluorescence microscopy considers the biochemical composition of the biological fluid and carries information about the concentration of molecular complexes of proteins, NADH, flavins, porphyrins, etc. In the early post-mortem period, changes in the cerebrospinal fluid begin precisely with changes in the concentration of biochemical compounds, and crystalline changes are secondary, so it can be argued that this method is most effective for diagnosing the progression of the time in the first hours after death. Conclusions: Fluorescent laser polarimetric methods allow accurate estimation of the postmortem interval during the first hours after death.  While, the polarization methods is more effective during the long-term periods of time, but has less precision.

scholarly journals Evaluating the utility of time-lapse imaging in the estimation of post-mortem interval: An Australian case study

2019 ◽  
Vol 1 ◽  
pp. 204-210 ◽  
Author(s):  
Alyson Wilson ◽  
Stanley Serafin ◽  
Dilan Seckiner ◽  
Rachel Berry ◽  
Xanthé Mallett
Keyword(s):  
Time Lapse ◽  
Post Mortem ◽  
Post Mortem Interval ◽  
Australian Case ◽  
Time Lapse Imaging

scholarly journals Subtle changes of the crystalline lens after cycloplegia: a retrospective study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Cheng Dai ◽  
Meng Liu ◽  
Xiaodong Lv ◽  
Binzhong Li
Keyword(s):  
Retrospective Study ◽  
Children And Adolescents ◽  
Population Change ◽  
Anterior Segment ◽  
Anterior Chamber Depth ◽  
Crystalline Lens ◽  
Equivalent Diameter ◽  
Crystalline Morphology ◽  
Significant Difference ◽  
Before And After

Abstract Background The purpose of this study was to evaluate the shape of the crystalline lens in terms of biometry and diopters before and after cycloplegia using the CASIA2 swept-source (SS) optical coherence tomography (OCT) system on the anterior segment. Methods This was a retrospective study. Children and adolescents (26 males and 29 females, aged 4–21 years) with simple ametropia were selected for optometry and CASIA2 imaging at 2 separate visits before and after cycloplegia. Diopter values were derived from the spherical power (S) obtained by optometry. Biometric parameters of the crystalline lens, including the anterior chamber depth (ACD), anterior and posterior curvature of the lens (ACL and PCL), lens thickness (LTH), lens decentration (LD), lens tilt (LT), and equivalent diameter of the lens (LED), were measured by the CASIA2 system. The differences in these parameters after compared with before cycloplegia were determined, and their relationships were analyzed. Results Fifty-five participants (106 eyes) were initially enrolled. There was a significant difference (P < 0.05) in the S (t=-7.026, P < 0.001), ACD (t=-8.796, P < 0.001), ACL (t=-13.263, P < 0.001) and LTH (t = 7.363, P < 0.001) after compared with before cycloplegia. The change in the PCL (t = 1.557, P = 0.122), LD (t = 0.876, P = 0.383), LT (t = 0.440, P = 0.661) and LED (t=-0.351, P = 0.726) was not statistically significant (P > 0.05). There was a significant (P < 0.05) correlation of the change in the S with that in the ACL (r = 0.466, P < 0.001), LTH (r=-0.592, P < 0.001), and LED (r = 0.223, P = 0.021) but not the PCL (r = 0.19, P = 0.051), LD (r=-0.048, P = 0.0628) or LT (r=-0.022, P = 0.822). Furthermore, the change in the ACD was closely related to the change in crystalline morphology. However, in children and adolescents, we found that the change in crystalline morphology was unrelated to age. Conclusions Changes in lens morphology after compared with before cycloplegia are mainly related to the ACL and LTH, but there is no difference in the PCL, LD, LT, or LED. In the adolescent population, change in the S is related to change in the ACL, LED and LTH. However, age is unrelated to the shape and tendency of the crystalline lens. Further research is required to determine whether the same conclusion applies to different age groups and different refractive states (myopia, hyperopia, emmetropia) .

scholarly journals Impact of Comingled Heterospecific Assemblages on Developmentally Based Estimates of the Post-Mortem Interval—A Study with Lucilia sericata (Meigen), Phormia regina (Meigen) and Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae)

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 280
Author(s):  
Krystal R. Hans ◽  
Sherah L. Vanlaerhoven
Keyword(s):  
Growth Rate ◽  
Development Time ◽  
Lucilia Sericata ◽  
Phormia Regina ◽  
Calliphora Vicina ◽  
Immature Stages ◽  
Post Mortem ◽  
Blow Fly ◽  
Blow Flies ◽  
Post Mortem Interval

Estimates of the minimum post-mortem interval (mPMI) using the development rate of blow flies (Diptera: Calliphoridae) are common in modern forensic entomology casework. These estimates are based on single species developing in the absence of heterospecific interactions. Yet, in real-world situations, it is not uncommon to have 2 or more blow fly species developing on a body. Species interactions have the potential to change the acceptance of resources as suitable for oviposition, the timing of oviposition, growth rate, size and development time of immature stages, as well as impacting the survival of immature stages to reach adult. This study measured larval development and growth rate of the blow flies Lucilia sericata (Meigen, 1826), Phormia regina (Meigen, 1826) and Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae) over five constant temperatures (15, 20, 25, 30, 35 °C), in the presence of conspecifics or two-species heterospecific assemblages. Temperature and species treatment interacted such that L. sericata larvae gained mass more rapidly when in the presence of P. regina at 20 and 30 °C, however only developed faster at first instar. At later stages, the presence of P. regina slowed development of L. sericata immatures. Development time of C. vicina immatures was not affected by the presence of P. regina, however larvae gained mass more slowly. Development time of P. regina immatures was faster in the presence of either L. sericata or C. vicina until third instar, at which point, the presence of L. sericata was neutral whereas C. vicina negatively impacted development time. Phormia regina larvae gained mass more rapidly in the presence of L. sericata at 20 °C but were negatively impacted at 25 °C by the presence of either L. sericata or C. vicina. The results of this study indicate that metrics such as development time or larval mass used for estimating mPMI with blow flies are impacted by the presence of comingled heterospecific blow fly assemblages. As the effects of heterospecific assemblages are not uniformly positive or negative between stages, temperatures or species combinations, more research into these effects is vital. Until then, caution should be used when estimating mPMI in cases with multiple blow fly species interacting on a body.

Mortality Benefit From the Passive Leg Raise Maneuver in Guiding Resuscitation of Septic Shock Patients: A Systematic Review and Meta-Analysis of Randomized Trials

2021 ◽  
pp. 088506662110197
Author(s):  
Moosa Azadian ◽  
Suyee Win ◽  
Amir Abdipour ◽  
Carolyn Krystal Kim ◽  
H. Bryant Nguyen
Keyword(s):  
Systematic Review ◽  
Septic Shock ◽  
Fluid Resuscitation ◽  
Standard Care ◽  
Meta Analysis ◽  
Risk Of Bias ◽  
Time Interval ◽  
Eligibility Criteria ◽  
Significant Difference ◽  
Passive Leg Raise

Background: Fluid therapy plays a major role in the management of critically ill patients. Yet assessment of intravascular volume in these patients is challenging. Different invasive and non-invasive methods have been used with variable results. The passive leg raise (PLR) maneuver has been recommended by international guidelines as a means to determine appropriate fluid resuscitation. We performed this systematic review and meta-analysis to determine if using this method of volume assessment has an impact on mortality outcome in patients with septic shock. Methods: This study is a systematic review and meta-analysis. We searched available data in the MEDLINE, CINAHL, EMBASE, and CENTRAL databases from inception until October 2020 for prospective, randomized, controlled trials that compared PLR-guided fluid resuscitation to standard care in adult patients with septic shock. Our primary outcome was mortality at the longest duration of follow-up. Results: We screened 1,425 article titles and abstracts. Of the 23 full-text articles reviewed, 5 studies with 462 patients met our eligibility criteria. Odds ratios (ORs) and associated 95% confidence intervals (CIs) for mortality at the longest reported time interval were calculated for each study. Using random effects modeling, the pooled OR (95% CI) for mortality with a PLR-guided resuscitation strategy was 0.82 (0.52 -1.30). The included studies were not blinded and they ranged from having low to high risk of bias using the Cochrane Risk of Bias Tool. Conclusion: Our analysis showed there was no statistically significant difference in mortality among septic shock patients treated with PLR-guided resuscitation vs. those with standard care.

scholarly journals Investigation of different stimulation patterns with doublet pulses to reduce muscle fatigue

2019 ◽  
Vol 6 ◽  
pp. 205566831982580 ◽  
Author(s):  
Ruslinda Ruslee ◽  
Jennifer Miller ◽  
Henrik Gollee
Keyword(s):  
Electrical Stimulation ◽  
Muscle Fatigue ◽  
Functional Electrical Stimulation ◽  
Muscle Activation ◽  
Motor Units ◽  
Pulse Interval ◽  
Time Interval ◽  
Fatigue Index ◽  
Significant Difference ◽  
Cord Injury

Introduction: Functional electrical stimulation is a common technique used in the rehabilitation of individuals with a spinal cord injury to produce functional movement of paralysed muscles. However, it is often associated with rapid muscle fatigue which limits its applications. Methods: The objective of this study is to investigate the effects on the onset of fatigue of different multi-electrode patterns of stimulation via multiple pairs of electrodes using doublet pulses: Synchronous stimulation is compared to asynchronous stimulation patterns which are activated sequentially (AsynS) or randomly (AsynR), mimicking voluntary muscle activation by targeting different motor units. We investigated these three different approaches by applying stimulation to the gastrocnemius muscle repeatedly for 10 min (300 ms stimulation followed by 700 ms of no-stimulation) with 40 Hz effective frequency for all protocols and doublet pulses with an inter-pulse-interval of 6 ms. Eleven able-bodied volunteers (28 ± 3 years old) participated in this study. Ultrasound videos were recorded during stimulation to allow evaluation of changes in muscle morphology. The main fatigue indicators we focused on were the normalised fatigue index, fatigue time interval and pre-post twitch–tetanus ratio. Results: The results demonstrate that asynchronous stimulation with doublet pulses gives a higher normalised fatigue index (0.80 ± 0.08 and 0.87 ± 0.08) for AsynS and AsynR, respectively, than synchronous stimulation (0.62 ± 0.06). Furthermore, a longer fatigue time interval for AsynS (302.2 ± 230.9 s) and AsynR (384.4 ± 279.0 s) compared to synchronous stimulation (68.0 ± 30.5 s) indicates that fatigue occurs later during asynchronous stimulation; however, this was only found to be statistically significant for one of two methods used to calculate the group mean. Although no significant difference was found in pre-post twitch–tetanus ratio, there was a trend towards these effects. Conclusion: In this study, we proposed an asynchronous stimulation pattern for the application of functional electrical stimulation and investigated its suitability for reducing muscle fatigue compared to previous methods. The results show that asynchronous multi-electrode stimulation patterns with doublet pulses may improve fatigue resistance in functional electrical stimulation applications in some conditions.

Sign in / Sign up

Export Citation Format

Share Document