Correlation of the circumstances of death with the pathologic findings in this prospective study of deaths by hanging affords insight pertaining to certain of the pathophysiologic mechanisms involved in fatalities of this type. The presence of conjunctival and facial/periorbital petechial hemorrhages correlates with increasing levels of body support below the point of ligature suspension. Hyoid bone and/or thyroid cartilage fractures (found in 26% of cases) are most frequently identified in those persons found completely suspended and in victims in the older age ranges. No hyoid bone/thyroid cartilage fractures, internal soft tissue injury, or petechiae were present in 13 (21%) of the study cases.

Two hundred twenty-six suicides by firearms were analyzed to determine the entrance wound site. Overall, the head was the most favored site, accounting for 74% of the wounds; specifically, the right temple accounted for 39% of the wounds. The data were further examined in terms of specific weapon types. In the case of handguns, the preference for the temple was even more prominent, with this site accounting for nearly two thirds of the wounds. With long guns the predominance of head wounds was less pronounced but still present. Correlations with sex and age showed no significant differences in choice of site but did show differences in selection of gunshot as the means of suicide. Correlations of site with handedness showed that most individuals held true to form but that a significant proportion (8%) inflicted their wounds on the other side. Finally, three cases of suicide by multiple gunshots are presented.

The amounts of surfactant in human lung tissue and in the alveolar pool have not been extensively reported. We used 24 human lungs from persons over the age range of 13 mo to 80 yr to investigate whether the amount of saturated phosphatidylcholine (Sat-PC) in the human lung changed with age. Lung lavages also were obtained from 10 lungs at autopsy for measurements of the alveolar Sat-PC and surfactant protein-A (SP-A) concentrations. We found that (mean +/- SEM) lung Sat-PC/body weight (28.4 +/- 2.2 mumol/kg), Sat-PC/lung protein (0.060 +/- 0.005 mumol/mg), and Sat-PC/lung deoxyribonucleic acid (DNA) (0.23 +/- 0.01 mumol/mg) did not vary significantly with age. The amounts of alveolar Sat-PC (1.9 +/- 0.2 mumol/kg) and SP-A (105 +/- 15 micrograms/kg) were lower than previous estimates in other species. The relatively small surfactant pools in the human may make the lung more susceptible to injuries that interfere with surfactant function.

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Purified preparations of human C'1 esterase, C'4, C'2, C'3, and C'5 were labeled with 125I. Reaction mixtures were prepared containing a single labeled component and other unlabled components. After incubation at 37°C for 10 min at pH 7.4 in the presence of 5 x 10–4 M Mg2+, they were adjusted to pH 3.5 and subjected to sucrose density gradient ultracentrifugation and gel filtration at pH 3.5. In all cases, an activity capable of contracting guinea pig ileum with tachyphylaxis was obtained in low molecular weight fractions. However, these fractions were labeled only when 125I-C'3 was employed, indicating that biological activity was associated with a cleavage product of C'3. This fragment has been designated F(a)C'3 in a nomenclature consistent with that of immunoglobulin degradation products. The much larger, residual portion of the C'3 molecule has been designated F(b)C'3. The biochemical characteristics of generation of F(a)C'3 were consistent with a mechanism involving action of C'1 esterase on C'4 and C'2, activation of C'2, and cleavage of C'3. F(a)C'3 had a molecular weight by gel filtration techniques of 6800 or less. It was thermostable and susceptible to inactivation by endo- and exopeptidases. The isolated fragment possessed all of the biological properties of unfractionated mixtures of C'1 esterase, C'4, C'2, and C'3. In addition to contraction of guinea pig ileum, these included failure to contract rat uterus, enhancement of vascular permeability in guinea pig skin, degranulation of mast cells in guinea pig mesentery, and release of histamine from rat peritoneal mast cells. F(a)C'3 did not cross-desensitize guinea pig ileum to rat agar anaphylatoxin and vice versa. The existence of different protein fragments with anaphylatoxin properties has been discussed. Distinctive characteristics of F(a)C'3 from classical anaphylatoxin generated by treatment of fresh rat serum with agar have been indicated.