Correlación entre sodio, cloro y potasio del cuerpo vítreo y el intervalo postmortem sobre los 2. 850 msnm / Correlation between sodium, chlorine and potassium of the vitreous body and the postmortem interval above 2. 850 msnm

RESUMEN: El intervalo Postmortem (IPM) es un importante desafío por resolver en la patología forense, y consiste en poder determinar el tiempo transcurrido desde la muerte hasta el momento de la autopsia. Dada la poca confiabilidad de algunos métodos por la gran influencia de factores externos y propios del cadáver, la bioquímica forense ha recibido considerable atención por sus niveles de seguridad. La ciudad de Quito se ubica en la cordillera de Los Andes a 2850 msnm, sin embargo, en la literatura no existen reportes de medición de estos parámetros a una altura como ésta. El objetivo fue establecer una correlación entre sodio (Na+), cloro (Cl-) y potasio (K+) del humor vítreo del cuerpo vítreo y el IPM a la altura de la ciudad de Quito. Para el estudio se utilizaron 128 muestras de cuerpo vítreo provenientes de 16 autopsias practicadas en la Unidad de Medicina Legal Zona 9, en IPM de 6, 12, 24, 48, 72, 96, 120 y 144 horas. Para la obtención del humor vítreo se siguió el método convencional, se dividió para las 8 alícuotas y se llevó a congelación -20 °C hasta el momento de su análisis. La cuantificación de la concentración de electrolitos Na+, Cl- y Potasio+ se realizó mediante analizador ISE de Roche Cobas (Roche Diagnostics) C501, calibrado para uroanálisis, y no fue necesaria la dilución. Durante la calibración y cada tres muestras, se midió un estándar interno para corregir los efectos de la desviación sistemática en la calibración. El enfoque estadístico se basó en un análisis de correlación lineal, utilizando el coeficiente de correlación de Spearman. La correlación entre las horas postmortem y las concentraciones de los diferentes electrolitos, fueron estadísticamente significativas. Se pudo corroborar una correlación lineal significativa entre el IPM y el aumento del K+ en el HV.

SUMMARY: The postmortem interval (PMI) is an important challenge to be solved in forensic pathology, and it consists of being able to determine the time elapsed from death to the moment of autopsy. Given the unreliability of some methods due to the great influence of external factors and those specific to the corpse, forensic biochemistry has received considerable attention for its levels of safety. The city of Quito is located in the Andes mountain range at 2850 meters above sea level, however, in the literature there are no reports of measurement of these parameters at a height like this. The objective was to establish a correlation between sodium (Na+), chlorine (Cl-) and potassium (K+) of the vitreous humor and the MPI at a height of 2,850 masl. For the study, 128 samples of vitreous humor were used from 16 autopsies performed in the Zone 9 Legal Medicine Unit, in IPM of 6, 12, 24, 48, 72, 96, 120 and 144 hours. To obtain the vitreous humor, the conventional method was followed, it was divided for the 8 aliquots and it was frozen at -20 ° C until the moment of its analysis. The quantification of the concentration of electrolytes Na+, Cl- and K+ was carried out using an ISE analyzer from Roche Cobas (Roche Diagnostics) C501, calibrated for urinalysis, and no dilution was necessary. During calibration and every third sample, an internal standard was measured to correct for the effects of systematic deviation on the calibration. The statistical approach was based on a linear correlation analysis, using the Spearman correlation coefficient. The correlation between the postmortem hours and the concentrations of the different electrolytes were statistically significant. A significant linear correlation between the PMI and the increase in K+ in vitreous humor could be corroborated.

Study on vascular endothelial growth factor and its receptor in the vitreous of diabetic rats / Estudio del factor de crecimiento endotelial vascular y su receptor en el humor vítreo de ratas diabéticas

OBJECTIVE: To investigate the vitreous level of vascular endothelial growth factor (VEGF) and kinase insert domain-containing receptor (KDR) in diabetic rats, and to explore the role of VEGF and KDR in diabetic retinopathy. METHODS: Eighty-four adult Wistar rats were randomly divided into two groups. Fifty-eight rats in group A were injected intraperitoneally with streptozotocin to induce diabetes and 20 rats in group B were injected with physiological saline. Blood glucose meter was used to detect the blood glucose level at 72 hours after injection; blood glucose level >16.67 mmol/L was considered to be successful modelling. Blood glucose level was assayed and body mass was measured on the same modelling day, one week, two weeks and four weeks after modelling. Four weeks after modelling, the vitreous was taken and the VEGF and KDR levels were detected by enzyme-linked immunosorbent assay (ELISA). The eyeballs were fixed with paraform and embedded by petrolin for haematoxylin and eosin (H & E) staining. RESULTS: Forty-two rats survived and 16 rats died in group A. No rats died in group B. The blood glucose at one week, two weeks and four weeks between the two groups had statistical differences (p < 0.05). The weight at one week and two weeks between the two groups was not different but there was statistical difference at four weeks between the two groups (p < 0.01). The ELISA results showed that the VEGF and KDR levels were 0.276 ± 0.026 ng/mL and 2.936 ± 0.295 ng/mL in group A, 0.231 ± 0.021 ng/mL and 2.394 ± 0.227 ng/mL in group B, respectively. The VEGF and KDR levels of group A were higher than those of group B (p < 0.05). CONCLUSIONS: The changes of VEGF and KDR levels in the vitreous of diabetic rats were related to the early retinopathy induced by diabetes.

OBJETIVO: Investigar el nivel vítreo del factor de crecimiento endotelial vascular (FCEV) y receptor con dominio inserto-quinasa (KDR) en ratas diabéticas, y explorar el papel de FCEV y KDR en la retinopatía diabética. MÉTODOS: Ochenta y cuatro ratas adultas Wistar fueron divididas aleatoriamente en dos grupos. A cincuenta y ocho ratas en el grupo A se les inyectó estreptozotocinapor vía intraperitonealpara inducir diabetes, mientras que a 20 ratas en el grupo B se les inyectó una solución salina fisiológica. Se usó un medidor de glucosa en sangre para detectar el nivel de glucosa en sangre a las 72 horas después de la inyección. Un nivel de glucosa en sangre > 16.67 mmol/L se consideró como un modelo exitoso. Se analizó el nivel de glucosa en sangre, y se midió la masa corporal en el mismo día del modelado, y una semana, dos semanas, y cuatro semanas después del modelado. Cuatro semanas después del modelado, se tomó el humor vítreo, y los niveles de FCEV y KDR fueron detectados mediante ensayo por inmunoabsorción ligado a enzimas (ELISA). Los globos oculares fueron fijados con para formaldehido e incrustados por petrolin para tinción (H & E) hematoxilina-eosina. RESULTADOS: Cuarenta y dos ratas sobrevivieron y 16 ratas murieron en el grupo A. Ninguna de las ratas en el grupo B murió. La glucosa en la sangre a la semana, las dos semanas, y las cuatro semanas entre los dos grupos tuvo diferencias estadísticas (p < 0.05). El peso a la semana y a las dos semanas entre los dos grupos no fue diferente, pero hubo diferencia estadística a las cuatro semanas entre los dos grupos (p < 0.01). Los resultados de ELISA mostraron que los niveles de FCEV y KDR fueron 0.276 ± 0.026 ng/mLy 2.936 ± 0.295 ng/mL en el grupo A, 0.231 ± 0.021 ng/mL y 2.394 ± 0.227 ng/mL en el grupo B, respectivamente. Los niveles de FCEV y KDR del grupo A fueron superiores a los del grupo B (p < 0.05). CONCLUSIONES: Los cambios de nivel FCEV y KDR en el humor vítreo de las ratas diabéticas estaban asociados con la retinopatía temprana inducida por diabetes.

Concentration changes of potassium and hypoxanthine in vitreous humor of swine and its application to postmortem interval estimation / 法医学杂志

OBJECTIVE@#To investigate the relationship between postmortem interval (PMI) and concentration changes of components in swine vitreous humor.@*METHODS@#Ninety-six porcine eyes from swine dying from acute massive hemorrhage, being randomly divided into 24 groups, were stored in dark situation, at temperature of (15 +/- 2) degrees C and humidity of (50 +/- 5)% for 2-96 hours separately. The vitreous humor was collected. Concentrations of K+, Na+, Cl- and hypoxanthine (Hx) were analyzed by automatic biochemical analyzer and ultra performance liquid chromatograph (UPLC). The data were statistically analyzed by SPSS software.@*RESULTS@#Linear regression analysis showed that concentrations of vitreous K+ and Hx were positively correlated with PMI(R2=0.767 and R2 = 0.793, respectively). Binary linear regression showed a higher correlation for K+ and Hx with PMI estimation (R2 = 0.866). PMI was not significantly correlated with vitreous Na+ and Cl- concentrations.@*CONCLUSION@#Vitreous K+ and Hx concentrations can be used as the objective markers for PMI estimation. The binary linear regression functions of vitreous K+ and Hx concentrations with PMI are more accurate for estimating the PMI.

Analysis of alcohol mass concentration in corpse blood / 法医学杂志

The blood alcohol concentration (BAC) is an important evidence to determine the alcohol level at the time of death. But due to the postmortem synthesis and diffusion of alcohol, the cadaveric BAC can not always represent the original BAC at the time of death. It is a crucial problem to determine the original level in corpse. The article reviewed the following points: the distribution in corpse, and how to sample, the influences on the diffusion of alcohol and putrefaction, the discussion about alcohol mass concentration measure methods.

Advances in the studies of postmortem interval estimation by the levels of chemical components in human vitreous humor after death / 法医学杂志

Estimation of postmortem interval (PMI) is one of the problems that need to be solved for forensic examination of the dead body. Accurate estimation of PMI has great values to criminal investigation and trial. The levels of chemical components in human vitreous humor are changed with time after death, which can help estimate the PMI. The levels of certain chemical components, such as potassium, magnesium, ammonia, urea, creatinine, uric acid, hypoxanthine, lactic acid and so on, in human vitreous humor will gradually increase with time after death, while others such as calcium, sodium, enzymes, glucose, vitamin C and so on will decrease. The updates and advances in those studies were reviewed in this article.

Double logarithmic, linear relationship between postmortem vitreous sodium/potassium electrolytes concentration ratio and time since death in subjects of Chandigarh zone of Northwest India.

Present authors had recently demonstrated a highly significant double logarithmic linear relationship between time since death and serum sodium/potassium concentration ratio and also with the serum chloride concentration in humans. Consecutively the present study was carried out to substantiate this disposition in vitreous humour. The data on postmortem vitreous sodium/potassium electrolytes concentration ratio in 1026 subjects, revealed a highly significant relationship between logarithm of vitreous sodium/potassium electrolytes concentration ratio and logarithm of time since death upto 66 hrs. of death. Postmortem interval can be predicted from vitreous sodium/potassium electrolytes concentration ratio with standard error of estimate 0.1800 hrs. However, factors like environmental temperature, age & gender also influences it significantly.

Concentration changes of amylase in vitreous humor of acute pancreatitis associated with different postmortem interval in rabbits / 法医学杂志

OBJECTIVE@#To investigate concentration changes of amylase in rabbits vitreous humor of acute pancreatitis associated with postmortem different interval.@*METHODS@#To induce animal model of acute pancreatitis with sodium taurocholate, observed concentration changes of amylase after different postmortem interval, then compared with normal.@*RESULTS@#The concentration of amylase in vitreous humor of rabbit 24h after death were related to postmortem interval significantly; The concluded formulae of the relationship between postmortem interval and amylase concentration is y=8.7420+0.7699x-0.0083x2 (R2=92.62792, F=14.89734, P=0.001).@*CONCLUSION@#Concentration changes of amylase in vitreous humor of acute pancreatitis associated with postmortem interval may provide a new sensitive and objective method for the forensic early injury time estimation.

A study of correlation between vitreous potassium level and post mortem interval.

Present study was undertaken to study the correlation of potassium level of vitreous humor with time since death. Vitreous was collected from 150 medicolegal autopsy cases between August 2000 to March 2001 in Bharatpur Hospital, Bharatpur, Chitwan, Nepal. There was a linear increase in vitreous potassium level with rise of postmortem interval. This indicates that rise in potassium levels after death has a strong correlation with the PMI.

Study on the relationship between PMI and the concentration of 21 elements in vitreous humor of rabbit after death / 法医学杂志

OBJECTIVE@#To seek a precise method for estimating postmortem interval (PMI) in forensic medicine practice.@*METHODS@#This study detected the concentration of 21 elements in the vitreous humor of rabbit within 96 hours after death and explored the relationship between their concentration and PMI using the method of ICP-MS.@*RESULT@#It was shown that the concentration of 9 elements in vitreous humor of rabbit within different intervals after death were correlated to PMI available as a reference indicator to estimate PMI.@*CONCLUSION@#The changes in the concentration of certain elements in vitreous humor of vitreous humor are correlated with PMI and determination of such changes can be used to estimate the time of death.

Study on the relationship between PMI and the concentration of magnesium and iron in the vitreous humor of rabbit after death / 法医学杂志

OBJECTIVE@#To seek a exact method of estimating postmortem interval (PMI).@*METHODS@#This study detected the concentration of magnesium (Mg) and iron (Fe) in vitreous humor of rabbit at 96 h after death and explored the relationship between their concentration and PMI using a method ICP-MS.@*RESULTS@#The concentra-tion of Mg in vitreous humor of rabbit at 48 h after death and Fe in vitreous humor of rabbit at 6-48 h after death were related to PMI significantly. The formulae of the relationship between PMI and Mg concentrations is y = 0.0738x2 + 0.6997x + 11.45 (within 48 h, R2 = 0.9119). The formulae of the relationship between PMI and Fe concentrations is y = 0.0411x2 - 0.3148x + 1.4113 (within 6-48 h, R2 = 0.9594).@*CONCLUSION@#The concentration of Mg in vitreous humor of rabbit at 48 h after death and Fe in vitreous humor of rabbit at 6-48 h after death may be as reference indicator to estimate PMI.

Study on the relationship between PMI and the concentration of zincum and nickel in the vitreous humor of rabbit after death / 法医学杂志

OBJECTIVE@#To seek a exact method of estimating postmortem interval (PMI).@*METHODS@#This study detected the concentration of zincum(Zn) and nickel(Ni) in vitreous humor of rabbit at hour 96 after death and explored the relationship between their concentration and PMI using a method ICP-MS.@*RESULTS@#The concentration of Zn and Ni in vitreous humor of rabbit at hour 24 after death were related to PMI significantly; The formulae of the relationship between PMI and Zn concentrations is y = 0.1404x2 - 1.3351x + 3.8298 (within 24 h; R2 = 0.9202). The formula of the relationship between PMI and Ni concentrations is y = 0.0043x2 - 0.0596x + 0.2665(within 24 h; R2 = 0.9103).@*CONCLUSION@#The concentration of Zn and Ni in vitreous humor of rabbit may be a reference indicator to estimate early PMI.

Raddioactive fucose as a tool for studying glycoprotein secretion

The efficiency and reliability of radioactive fucose as a specific label for newly synthesized glycoproteins were investigated. Young adult male rabbits were injected intravitreally with [3H]-fucose, [3H]-galactose, [3H]-mannose, N-acetyl-[3H]-glucosamine or N-acetyl-[3H]-mannosamine, and killed 40 h after injection. In another series of experiments rabbits were injected with either [3H]-fucose or several tritiated amino acids and the specific activity of the vitreous proteins was determined. Vitreous samples were also processed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and histological sections of retina, ciliary body and lens (the eye components around the vitreous body) were processed for radioautography. The specific activity (counts per minute per microgram of protein) of the glycoproteins labeled with [3H]-fucose was always much higher than that of the proteins labeled with any of the other monosaccharides or any of the amino acids. There was a good correlation between the specific activity of the proteins labeled by any of the above precursors and the density of the vitreous protein bands detected by fluorography. This was also true for the silver grain density on the radioautographs of the histological sections of retina, ciliary body and lens. The contribution of radioautography (after[3H]-fucose administration) to the elucidation of the biogenesis of lysosomal and membrane glyco-proteins and to the determination of the intracellular process of protein secretion was reviewed. Radioactive fucose is the precursor of choice for studying glycoprotein secretion because it specific, efficient and practical for this purpose.

Determination of dexamethasone sodium phosphate in the vitreous by high performance liquid chromatography

Dexamethasone sodium phosphate (DSP) is increasingly used in the treatment of ocular inflammatory diseases by systemic, periocular, and recently, intravitreal injection. We have developed a method for the determination of vitreous levels of DSP by reverse phase HPLC. In this method, co-elution of vitreous proteins with DSP is resolved by a prior sample clean-up procedure using Waters Sep-Pak C18 cartridge; the protein is separated and eluted with water while DSP, paraben and prednisone are eluted with methanol. DSP in the resulting sample is then separated by reverse phase HPLC and quantified by UV absorption at 254 nm. The recovery of DSP through the sample clean-up is 68.9 +/- 3.0%. DSP quantitation is linear from 0.1 mg to 1.0 mg per 1.0 ml vitreous. This method provides a simple, sensitive and reliable technique for determining the vitreous levels of DSP.