Accidental hydrocarbon ingestion cases telephoned to a regional poison center

One hundred eighty-four telephone calls to the Texas State Poison Center concerning accidental hydrocarbon ingestion were reviewed in an attempt to define the risk of developing any subsequent medical problem requiring therapeutic intervention. Special attention was given to changing symptom severity in an attempt to evaluate its usefulness in predicting future complications. One hundred twenty patients (65%) had no initial symptoms and remained asymptomatic throughout an 18-hour follow-up period. Sixty-two (34%) of patients had symptoms initially but quickly became asymptomatic. Two (1%) developed significant complications (one chemical pneumonitis, one death). These data suggest that the risk of significant complications after accidental hydrocarbon ingestion is low (approximately 1% of patients at risk). Patients who are asymptomatic or who quickly become asymptomatic can be watched safely at home, and referral of asymptomatic patients to a hospital may be unwarranted.     

Antagonist moment of force during maximal knee extension in pubertal boys: effects of quadriceps fatigue

The examination of the moment exerted by the hamstrings during maximum isokinetic knee extensor tests is useful when comparing isokinetic strength and muscle activity patterns between children and adults. The purpose of this study was to examine the effect of antagonist moment of the hamstrings on the isokinetic moment of the knee extensors in pubertal children and to determine whether this effect is altered following a fatigue task. Eighteen healthy pubertal males [age 14.3 (0.5) years] performed 34 maximal isokinetic concentric efforts of the knee extensors at 60°·s⁻¹. The average moment of force and electromyographic (aEMG) signal of vastus medialis (VM), vastus lateralis (VL) and biceps femoris (BF) at 11–30°, 31–50°, 51–70° and 71–90° of knee flexion were calculated for each repetition. The hamstrings antagonist moment was determined before and after the fatigue task by fitting the aEMG–moment relationship at different levels of muscle effort using second-degree polynomials. The percentage contribution of the antagonist moment to the resultant joint moment ranged from 7.1 % to 60.4 % throughout the range of motion, with the highest percentage observed close to full knee extension (11–30°). The antagonist effect was significantly greater during concentric tests of the knee extensors compared to the corresponding eccentric tests (p<0.05). Following the fatigue test, there was an overall decline of the resultant joint moment, but no changes in the predicted hamstrings moment were observed. These results indicate that when testing maximal knee extensor isokinetic strength in pubertal boys, activity of the hamstrings implies a reduction of the net extensor moment as compared to the isolated capacity of the knee extensors. However, this antagonist effect is not altered following the performance of an isokinetic fatigue knee extension task. Electronic Publication     

Inhibition of host resistance by nutritional hypercholesteremia.

Previous experiments showed that nutritionally induced hypercholesteremia in mice caused an increase in susceptibility to coxsackievirus B, with a marked suppression of cellular infiltrates in infected tissues and an increased mortality. The present studies demonstrated that a hypercholesteremic diet was associated with an inhibition in host resistance as measured by susceptibility to Listeria monocytogenes infection and the growth of two transplanted syngeneic murine tumors. Moreover, the ability of Corynebacterium parvum to induce regression of a transplanted methylcholanthrene-induced fibrosarcoma was inhibited in hypercholesteremic hosts, as was the histiocytic infiltration normally accompanying C. parvum inoculation. In contrast, the peritoneal macrophages from C. parvum-treated hypercholesteremic mice were indistinguishable from similarly treated macrophages from normal mice with respect to their in vitro tumoricidal activity and the presence of a cell surface antigen associated with activated macrophages. Hypercholesteremia was also associated with a decreased antibody response to sheep erythrocytes in vivo, but dit not appear to exert a detrimental effect on B- or T-cell blastogenesis when tested in vitro. The findings that the hypercholesteremic diet was associated with an impairment in the host immune response and increased susceptibility to viral, bacterial, and tumor cell challenge are discussed with respect to virus-lipid interactions in the pathogenesis of atherogenesis and diabetes mellitus.     

Passive immunity in calf rotavirus infections: maternal vaccination increases and prolongs immunoglobulin G1 antibody secretion in milk.

Ten heifers were inoculated on two occasions with an inactivated preparation of tissue culture-grown calf rotavirus, and a further ten heifers received a placebo vaccine. Serum anti-rotavirus antibody titers were significantly increased throughout pregnancy in the vaccinated group. After calving, the mean neutralizing antibody titer of colostral whey in control cows was 100, associated with immunoglobulins A and G1. No antibody was detected in the milk of these cows after the 4th day postpartum. The colostral whey from the vaccinated cows had a mean antibody titer of 20,452; 28 days after calving, the mean milk antibody titer was 320, associated mainly with immunoglobulin G1. Calves were challenged with a large oral inoculum of calf rotavirus at the 7th day of age. There was significant lengthening of the incubation and prepatent periods in calves born to vaccinated dams, but rotavirus-associated diarrhea of equal severity occurred in both groups. Evidence is presented which suggests that rotavirus antibody in milk can protect against a smaller challenge dose. Maternal immunization against rotavirus may be a practical proposition.     

Cancer patients who refuse treatment

The value of cancer treatment was assessed using a natural experiment where patients who refused treatment served as no-treatment controls in a situation where withholding treatment to form a control group is unethical. Each cancer patient who refused treatment in Alberta, Canada between 1975 and 1988 was compared with five subjects who accepted treatment, matched on cancer site, age, number of cancers, and time period. Variables associated with treatment-refusal were included in Cox's proportional hazards model of survival, with death from cancer as the endpoint and deaths from other causes as censored observations. Treatment was refused at a rate of 7.5 per 1,000. One-third of patients who refused treatment had lung cancer and most had unstaged disease. Treatment refusal was associated with a difference in median survival of approximately nine months. Site-specific analyses showed a range of effects. Case fatality among the treated patients fell by approximately 10 percent during the 14-year study period. Even in advanced disease, treatment can result in improved survival. However, the results of this study must be interpreted with caution and cannot be generalized to all cancer patients.Dr Huchcroft and Mr Snodgrass are with the Alberta Cancer Board, Calgary, Alberta, Canada. Address correspondence to Dr Shirley Huchcroft, Senior Scientist, Division of Epidemiology and Preventive Oncology, Alberta Cancer Board, Calgary, Alberta, Canada T2N 4N2.     

Prevalence of rotavirus antibodies in a non-human primate colony

A total of 51 monkeys maintained in a colony at the Institute of Primate Research (Kenya) and housed in doors with natural lighting in a group cage were used in this study. Monkeys belonging to 3 species were selected at random and blood samples collected. The serum samples were screened for presence of neutralizing antibodies (VTN) to rhesus rotavirus (RRV) by virus neutralization assay. Virus neutralization was determined by 60% reduction in fluorescent focus units (ffu). 96% of the animals screened had naturally occurring antibodies to rhesus rotavirus. Another group of 11 lactating monkeys (5 baboons, 6 vervets) and their infants were screened further for presence of IgG and IgA antibodies in serum and breast milk (mothers). Overall, the mothers had higher titres of both IgG and IgA than the infants. Taken together, these results demonstrate rotavirus infection is endemic in this primate colony. This mimics the human situation, hence, captive non human primates (such as the baboons) could be a suitable model for testing rotavirus candidate vaccines and for investigating the possible application in humans of passive-active immunization strategy.     

Human preferences for sexually dimorphic faces may be evolutionarily novel

A large literature proposes that preferences for exaggerated sex typicality in human faces (masculinity/femininity) reflect a long evolutionary history of sexual and social selection. This proposal implies that dimorphism was important to judgments of attractiveness and personality in ancestral environments. It is difficult to evaluate, however, because most available data come from large-scale, industrialized, urban populations. Here, we report the results for 12 populations with very diverse levels of economic development. Surprisingly, preferences for exaggerated sex-specific traits are only found in the novel, highly developed environments. Similarly, perceptions that masculine males look aggressive increase strongly with development and, specifically, urbanization. These data challenge the hypothesis that facial dimorphism was an important ancestral signal of heritable mate value. One possibility is that highly developed environments provide novel opportunities to discern relationships between facial traits and behavior by exposing individuals to large numbers of unfamiliar faces, revealing patterns too subtle to detect with smaller samples.Inspired by evidence from nonhuman species indicating that exaggerated sex-typical traits (e.g., large antlers, peacock tails) are often attractive to mates or intimidating to rivals (1, 2), morphological sex typicality in humans (masculinity in men and femininity in women) has been the focus of considerable research into attractiveness judgments (3, 4). Facial attractiveness research has been revolutionized by this explanatory framework from the biological sciences, which proposes that attractive human faces honestly signaled mate value within ancestral environments.An influential proposal is that facial femininity is a signal of fertility in human female faces (4–9) because, within same-age women, it is associated with estrogens (10), which, in turn, are related to measures of reproductive health (11). Like ovarian function, facial femininity declines with age in adulthood (12, 13). The proposal that fertile women should be attractive to men is seemingly uncontroversial because males who discriminatively mate with fertile females should achieve a straightforward reproductive advantage over those males who do not, with all other factors being equal (6). Although direct associations between facial femininity and fertility have not been demonstrated, the consensus from Western preferences, and from the limited cross-cultural data available, is that femininity is attractive, as predicted by the fertility hypothesis (14–17). In environments where fertility is high and variable, this relationship should be even more apparent.In male faces, masculinity has been variously proposed to signal heritable disease resistance (“good genes” or “immunocompetence”) (4, 15, 18–22) and/or perceived as a cue of aggressiveness and, consequently, intrasexual competitiveness (22, 23). The “honesty” of face shape as an indicator of immunocompetence is proposed to be the result of an immunosuppressive effect of testosterone. Because testosterone influences the growth of sex-typical traits in many species (24, 25), masculine facial shape is proposed to be a costly, and thus honest, signal of male quality (22). The hypothesis that cues of heritable health should be attractive to females is widely accepted (26), although the evidence for a link between heritable health and masculinity in humans is tentative at best (22).Support for a link between masculinity and aggression is largely indirect, and it consists of an association between testosterone and both aggressive behavior (27, 28) and face shape (25), in addition to the fact that honest signaling of dominance is commonly observed in nonhuman species (3). Masculine faces are perceived as aggressive in those groups (i.e., urban, Western) where the relationship has been tested (29). Because masculinity may signal both (desirable) immunity and (potentially costly) aggression in humans, some authors have proposed that preferences for masculinity reflect women trading-off benefits of traits putatively associated with health against those traits associated with prosocial behaviors, such as parental investment (23, 30, 31).Consistent with both of these proposals, data indicate that preferences for masculinity are stronger in circumstances where indirect benefits (heritable quality) can be realized without accompanying direct costs (aggression and low paternal investment). Such circumstances include judging attractiveness in the context of a short-term (vs. a long-term) relationship (32) and in the follicular phase of the menstrual cycle when conception following intercourse is most likely (33). Masculinity is also reported to be more strongly preferred in environments with relatively high pathogen burdens (19, 30) and in environments with higher local homicide rates (23), which has been interpreted as a response to variation in the benefits of heritable disease resistance (19) and in the net benefits conferred by aggressive males under varying levels of male–male competition (23).All of this supporting evidence comes with a very important caveat; although there has been some cross-cultural work in this area (34), the majority of studies have been conducted in Western, often student, populations characterized by high levels of development and urbanization [Western, educated, industrialized, rich, and democratic; so-called WEIRD participants (35)]. Research on preferences in other groups is scant and methodologically inconsistent, using Internet-based designs or a limited cross-cultural component (7, 15–18). Because there are differences between Western/non-Western and industrial/small-scale societies in many behaviors, including aspects of visual perception and mate choice (35), this over-representation greatly limits generalizability. Perhaps most importantly, large-scale (post)industrial societies present inhabitants with large numbers of unfamiliar faces and provide venues for the efficient exchange of (visual) social information (e.g., posters, television, Internet); these factors may be instrumental in the acquisition and reinforcement of preferences (36–39). It is possible therefore that rather than being a legacy of ancestral selection pressures, preferences for dimorphism emerge in large urban groups as a byproduct of the information-processing strategies used to process large amounts of social information or in response to arbitrary cultural norms.Development also introduces an increased presence of highly differentiated social roles that arise from a greater division of labor, along with opportunities to acquire prestige without strength or aggression. Because partner preferences have been proposed to develop in response to sex-typical social roles (40, 41), it is possible that increasingly differentiated roles could influence masculinity preferences if desirable social roles not present in less developed groups are associated with facial appearance.We assessed preferences for, and trait attributions made to, faces varying in dimorphism in a cross-cultural sample of 12 groups, including non-Western, nonstudent, and small-scale societies (n = 962; Tables S1 and S2). We tested the predictions, derived from the immunocompetence handicapping hypothesis, that (i) preferences for dimorphism will be stronger in less developed groups and (ii) masculine faces would be perceived as aggressive in all populations, with perceptions in low-development groups at least as strong as in groups with high development. We estimated social development with the Human Development Index (HDI), which is a composite indicator compiled by the United Nations Development Program. To investigate which aspects of development were associated with variation in perception of our facial stimuli, we took the World Health Organization measures of years lost to disease and United Nations (UN) measures of homicide rates as proxy measures of disease burden and male intrasexual competition, respectively (both log-transformed), and UN measures of levels of urbanization. Using these national statistics almost certainly underestimates disease burden in the small-scale societies in our sample, which is a conservative estimate with regard to our hypotheses.

Table 1.

Summary information for the groups tested