Philip Snoy

Physiological Correlates of Aggression and Impulsivity in Free-Ranging Female Primates

We examined the relations among cerebrospinal fluid (CSF) monoamine metabolite concentrations, plasma hormone concentrations, aggression, and impulsive risk-taking behavior in a free-ranging population of female rhesus macaques. We selected 44 juvenile female rhesus macaques as subjects from a population of approximately 3000 macaques that inhabit a 475-acre Sea Island. We obtained CSF and blood samples, and recorded behavioral observations over a subsequent 18-month period. Our results indicate an inverse correlation between CSF concentrations of the major serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA), and the frequency of low-intensity restrained aggression typically associated with matrilineal defense of social status. In contrast, previous research with males has shown an inverse correlation between CSF 5-HIAA concentrations and levels of violent unstrained aggression typically associated with traumatic injury and death. We also noted a negative correlation between plasma concentrations of the stress hormone cortisol and the frequency of low-intensity aggressive acts, a finding not reported in our previous studies with males. Further examination revealed a negative correlation between CSF 5-HIAA concentrations and the rate of long dangerous leaps through the forest canopy, suggesting that the relation between low serotonergic functioning and impulsivity may generalize to both female and male primates. These results indicate that females with low CSF 5-HIAA concentrations, like their male counterparts, are at increased risk for impulsive temperament, but that unlike males, females may be buffered from this risk through intersexual differences in life history patterns and social affiliation.

Non-A, non-B hepatitis associated with the administration of intravenous immunoglobulin—transmission studies in chimpanzees

Abstract Recent reports have described serum aminotransferase elevations in hypogammaglobulinaemic patients following prophylactic infusions of intravenous immunoglobulins. Whether these serum enzyme elevations represent viral non-A, non-B hepatitis (NANBH) or are related to hepatocyte damage secondary to non-infectious mechanisms has not always been clear. We inoculated two chimpanzees with a serum pool obtained from five hypogammaglobulinaemic patients with persistent alanine aminotransferase (ALT) elevations following prophylactic treatment with an intravenous immunoglobulin (Gammonativ ® , KabiVitrum). Both chimpanzees developed ALT elevations post-inoculation but with quite different patterns. One (1278) had elevated ALT levels at weeks 5–13 after serum inoculation whereas the other (1279) showed a biphasic pattern of ALT elevations during weeks 11–13 and 21–27. The earliest serum ALT elevations were accompanied by marked lymphocytic infiltration of the liver in the absence of characteristic cytoplasmic tubular structures in hepatocytes examined by electron microscopy. Chimpanzee 1279, however, developed tubular structures of the C-III type concomitantly with its later ALT elevations, suggesting the possibility that the serum inoculum contained two NANBH agents and thus that the intravenous immunoglobulin itself may have been contaminated with two NANBH agents.

Nondetection of Infectious Hepatitis B Virus in a Human Hepatoma Cell Line Producing Hepatitis B Surface Antigen

The PLC/PRF/5 human hepatoma cell line producing hepatitis B surface antigen (HBsAg) was studied to determine whether infectious hepatitis B virus (HBV) was also being produced. 2 chimpanzees with no previous exposure to HBV and no serologic markers of past or active HBV infection were inoculated intravenously with 50 ml of either tissue culture supernatant fluid (357 ng/ml HBsAg) or a suspension of cells disrupted by repeated freeze-thaw cycles (57 ng/ml HBsAg). No evidence of HBV infection was detected in either chimpanzee during 6 months of evaluation. This study suggests that the expression of a portion of the HBV genome, when a portion or all of that genome has been incorporated into a host cell, can result in the production of HBsAg without infectious HBV. If it becomes possible to produce a similar expression of this portion of the genome by itself in nonmalignant cells, HBsAg without HBV may be produced in vitro for use in hepatitis B vaccines.