Age estimation from quantitation of features of "chest plate" X-rays.

This study presents a method for estimating the age at death from the quantitation of roentgenologic features of X-ray films of chest plates obtained during routine autopsies. Multiple linear regression analysis allows estimation of coefficients of regression of features on known age-at-death individuals. The regression equation can be used in turn for age estimation of an unknown age-at-death individual. The accuracy of age estimation is about +/- 8.4 years (standard error) which is in the range of previously published macroscopic methods, though the present method is much faster and simpler.

Postmortem interval estimation by biochemical determination in birds muscle.

Experimental postmortem interval estimation was assayed by various biochemical components of hens pectoral muscle. Among them, only percentage of non-protein nitrogen on total soluble protein, asparatic amino transferase activity and creatinine concentration showed significant correlation with time after death. Asparatic amino transferase was negatively correlated and non-protein nitrogen percentage and creatinine were positively correlated to postmortem interval. The stronger correlation (0.925) was found for creatinine.

Automated image analysis of myocardial collagen pattern in pressure and volume overload in rat cardiac hypertrophy.

An automated image analysis system was used to analyze the collagen pattern in picrosirius-stained sections of the left ventricular myocardium from 27 rats: 9 sham-operated animals (controls), 9 animals with one-clip, two-kidney Goldblatt renovascular hypertension (RVH) and 9 animals with an aortocaval fistula (ACF) model of volume overload hypertrophy. The collagen content and fiber thickness were significantly increased in the RVH group as compared to the ACF and sham-operated groups (P less than .001). These parameters were correlated to the left ventricular wall thickness (R = .66; P less than .01). On the other hand, form factors were significantly increased in both treated groups as compared to the controls. These findings indicate that increased collagen formation and increased left ventricular wall thickness probably depend on the type of load and were particularly important when afterload is increased.

Assessment of validity of DNA measurement in tissue sections by model simulation.

Computer modelling is used to simulate nuclear segments obtained by random sectioning through tissue. A few more computations lead to DNA measurement simulation. Two methods of DNA measurement (a direct one and a variant of the "plug" method) are tested on simulated diploid, tetraploid and octaploid cell populations. The two methods result in negatively skewed DNA frequency distributions. Both the right skewness and the coefficient of variation of measurements are increasing with the ploidy level because nuclear DNA content is assumed to be related to nuclear size in the chosen model. Observed mean values are biased underestimates of expected values but are strongly correlated to the degree of ploidy. The variant of the "plug" method gives rise to smaller coefficients of variation. Finally, the bias introduced by measuring nuclear segments instead of whole nuclei increases the variance of measurements but contributes to less than half the experimentally observed variance. Our conclusion is that microspectrophotometry on tissue sections is a valuable method for DNA content evaluation of small clusters of pathological cells as one may find in endoscopic biopsies.

Discrimination between precancerous and cancerous lesions of the uterine cervix by DNA measurements on tissue sections.

Morphologically typical uterine cervical biopsies were separated into normal cervices, condylomas and cervical intraepithelial neoplasias (CIN) grades I, II and III. At least 100 nuclei per lesion were measured on 4 micron Feulgen-stained sections using a Zeiss microspectrophotometer, with a variant of the plug method used to compute the nuclear DNA content. DNA distribution histograms were then decomposed into subsets of diploid, tetraploid, octoploid and aneuploid cells. The decomposition, which assumed a log-normal model of polydiploidy distribution, led to the identification of six indices: (1) the percentage of diploid cells, (2) the percentage of tetraploid cells, (3) the percentage of octoploid cells, (4) the percentage of aneuploid cells with DNA contents less than tetraploidy, (5) the percentage of aneuploid cells with DNA contents between tetraploidy and octaploidy and (6) the percentage of aneuploid cells with DNA contents greater than octoploidy. These indices, along with the mean nuclear radius, the 5c exceeding rate and the 2c deviation index, generated a nine-dimensional space. Two methods of discriminant analysis on this space showed discriminating powers of 78.22% and 87.13%, respectively, as compared to the original diagnoses. The most discriminating variable in both analyses appeared to be the percentage of octoploid cells.

[The validity of measuring methods for intranuclear DNA on thin sections. Theoretical and experimental study]. / Validité des méthodes de mesure d'ADN intranucléaire sur coupe fine. Etude théorique et expérimentale.

Computer modelling is used to simulate nuclear segments obtained by random sectioning through tissue. A few more computations lead to DNA measurement simulation. Simulation results in negatively skewed DNA frequency distributions. Both the right skewness and the coefficient of variation of measurements are increasing with the ploidy level because nuclear DNA content is assumed to be related to nuclear size in the chosen model. Observed mean values are biased underestimates of expected values but are strongly correlated to the degree of ploidy. Finally, the bias introduced by measuring nuclear segments instead of whole nuclei increases the variance of measurements but contributes to less than half the experimentally observed variance. Our conclusion is that microspectrophotometry on tissue sections is a valuable method for DNA content evaluation of small clusters of pathological cells as one may find in endoscopic biopsies.