Michał Szeremeta

Equilibria of Phosphatidylcholine − Ca2+ Ions in Monolayer at the Air/Water Interface

The effect of Ca(2+) ion interaction with monolayers of phosphatidylcholine (lecithin, L) was investigated at the air/water interface. We present surface tension measurements of lecithin monolayers obtained using a Langmuir method as a function of Ca(2+) ion concentration. The measurements were carried out at 22 degrees C using a Teflon trough and a Nima 9000 tensiometer. The interactions between lecithin and Ca(2+) ions result in significant deviations from the additivity rule. An equilibrium theory to describe the behavior of monolayer components at the air/water interface was developed in order to obtain the stability constants and area occupied by one molecule of LCa(+) and L(2)Ca complexes. The stability constants, K(1) = 1.92 x 10(3) m(2) mol(-1) and K(2) = 5.35 x 10(5) m(2) mol(-1) were calculated by inserting the experimental data. The value of area occupied by one LCa(+) complex is 65 A(2) molecule(-1), while the area occupied by an L(2)Ca complex is 117 A(2) molecule(-1).

The Effect of Fatal Carbon Monoxide Poisoning on the Surface Charge of Blood Cells

The objective of this investigation was to evaluate postmortem changes of electric charge of human erythrocytes and thrombocytes after fatal carbon monoxide (CO) poisoning. The surface charge density values were determined on the basis of the electrophoretic mobility measurements of the cells carried out at various pH values of electrolyte solution. The surface charge of erythrocyte membranes after fatal CO poisoning as well as after sudden unexpected death increased compared to the control group in the whole range of experimental pH values. Also, a slight shift of the isoelectric point of erythrocyte membranes to high pH values was observed. The surface charge of thrombocyte membranes after fatal CO poisoning decreased at low pH compared to the control group. However, at high pH, the values increased compared to the control group. The isoelectric point of thrombocyte membranes after fatal CO poisoning was considerably shifted toward low pH values compared to the control group. The observed changes are probably connected with the destruction of blood cell structure.

Changes in surface-charge density of blood cells after sudden unexpected death.

The objective of the investigation was evaluation of postmortem changes of electric charge of human erythrocyte and thrombocyte membranes after sudden unexpected death. The surface charge density values were determined on the basis of the electrophoretic mobility measurements of the cells carried out at various pHs of electrolyte solution. The interactions between both erythrocyte and thrombocyte membranes and electrolyte ions were studied. Values of parameters characterizing the membrane—that is, the total surface concentrations of both acidic and basic groups and their association constants with solution ions—were calculated on the basis of a four-equilibria mathematical model. The model was validated by comparison of these values to experimental data. We established that examined electric properties of the cell membranes are affected by sudden unexpected death. Postmortem processes occurring in the cell membranes can lead to disorders of existing equilibria, which in turn result in changes in values of all the above-mentioned parameters.

Fatal drowning as a result of an airplane crash: case report

An ULM (Ultra Light Motorized) plane Aeroprakt 22-L with two men on board dived unexpectedly into the Dworackie lake near the town of Olecko in Warmia and Mazury district, Northeastern Poland. The pilot and the passenger had multiorgan blunt injuries, including subdural and subarachnoid hemorrhage, fractured ribs, fractured thigh (in one of the deceased) and pulmonary contusions as a result of the impact with the lake. The multiorgan injuries and unconsciousness resulting from head trauma prevented the casualties from saving themselves. The underlying cause of the death was the crash into the lake, however drowning was assessed as the proximate cause of death. The accident was analyzed together with an account prepared by State Commission on Aircraft Accident Investigation and with the Human Factor Analysis and Classification System - HFACS (the standardized method of analysis of flight accidents, the tool originally developed and tested within the U.S. military).

An Unusual Medicolegal Case of 32-Year-Old Mother and Her 29-Week Fetus With Hemolysis, Elevated Liver Enzymes, and Low Platelet Count Syndrome: Case Report and Short Literature Review

Abstract Forensic medicine experts are well aware of blunt abdominal trauma, which often lead to death because of serious internal organ injury with severe blood loss. Sometimes careful examination of such cases may reveal some other underlying conditions, such as an existing disease that had contributed to the death or life-threatening complications. Our article presents a rare case of spontaneous hepatic rupture and intraperitoneal hemorrhage in a 32-year-old primigravida and her 29-week fetus, which was a result of hemolysis, elevated liver enzymes, and low platelet count syndrome. The said syndrome is a life-threatening obstetric complication usually considered to be a variant or complication of pre-eclampsia, which is characterized by hemolysis with microangiopathy, elevated liver enzymes, and low platelet count.

Changes in Surface Charge Density of Blood Cells in Fatal Accidental Hypothermia

The objective of this research was to evaluate postmortem changes concerning electric charge of human erythrocytes and thrombocytes in fatal accidental hypothermia. The surface charge density values were determined on the basis of the electrophoretic mobility measurements of the cells conducted at various pH values of electrolyte solution. The surface charge of erythrocyte membranes after fatal accidental hypothermia increased compared to the control group within whole range of experimental pH values. Moreover, a slight shift of the isoelectric point of erythrocyte membranes towards high pH values was observed. The surface charge of thrombocyte membranes in fatal accidental hypothermia decreased at low pH compared to the control group. However, at pH range 4–9, the values increased compared to the control group. The isoelectric point of thrombocyte membranes after fatal accidental hypothermia was slightly shifted towards low pH values compared to the control group. The observed changes are probably connected with the partial destruction and functional changes of the blood cell structure.

Analysis of suicide cases in post-mortem examination files of the Department of Forensic Medicine at the Medical University of Białystok (2003 to 2015)

Aim of the study: The study presents the analysis of suicides based on the material consisting of the results of medico-legal autopsies and case files of the Department of Forensic Medicine of the Medical University of Bialystok. Material and methods: The material consisted of 6752 protocols of medico-legal autopsies carried out in the years 2003-2015 and case files, which enabled to classify cases as suicidal. The analysis included the dynamics of suicides over the years, basic demographic characteristics of victims, the ways, the time and place of suicide, the state of sobriety, the frequency of injuries in different regions of the body. The data were analyzed statistically using tests such as: Shapiro-Wilk test, Mann-Whitney U test, nonparametric Kruskal-Wallis test by programme Statistica 10.0 by StatSoft. Results: The research showed that suicides represented 11.09% of all post-mortem examinations. A statistically significant association was found between the age of the person committing suicide and the place chosen for suicide (p = 0.038). Post hoc analysis demonstrated statistically significant differences (p = 0.046) between suicide committed outdoors and in the supervised area. There was a statistically significant association between the sex and the preferable place of committing suicide (p = 0.0001). A high percentage of suicides were committed in the place of residence. There was a statistically significant difference in blood alcohol levels in women and in men at the time of suicide (p = 0.0029). Conclusions: The study revealed the increase of the percentage of suicides in relation to previous years. Hanging is still the most popular method of suicide.

Genetic variation of 15 autosomal STRs in a population sample of Bedouins residing in the area of the Fourth Nile Cataract, Sudan

ABSTRACT The purpose of the paper was to report allelic frequencies of 15 autosomal STR markers (AmpFlSTR NGM PCR Amplification Kit) for Bedouin inhabitants in the area of the Fourth Nile Cataract in Sudan, and compute commonly used population and forensic biostatistical parameters. Buccal swabs were collected from 117 unrelated individuals. DNA was extracted using DNA QIAamp® DNA Mini Kit, and quantitated with Quantifiler Human Quantification Kit in a 7500 Real-Time PCR System. Amplification of 15 AmpFlSTR NGM PCR Kit loci was performed in PCR System 9700. Electrophoresis and typing were performed in 3130 Genetic Analyzer. Arlequin v3.5 software and PowerStats v1.2 spreadsheet were used for statistical calculations. The STR frequency distributions showed no deviations from HWE. The combined values of Matching Probability and Power of Exclusion are 1.77 × 10-18 and 0.9999996, respectively. The average observed heterozygosity over 15 loci is 0.8069. Five different allelic microvariants were found. A significant linkage disequilibrium was observed in five pairs of loci. A 15 STR population database has been established for Sudanese Bedouins. The systems studied have been shown to be useful tool for personal identification in this population.