Prevalence of Shiga toxin-producing Shigella species isolated from French travellers returning from the Caribbean: an emerging pathogen with international implications.

Shiga toxins (Stxs) are potent cytotoxins that inhibit host cell protein synthesis, leading to cell death. Classically, these toxins are associated with intestinal infections due to Stx-producing Escherichia coli or Shigella dysenteriae serotype 1, and infections with these strains can lead to haemolytic-uraemic syndrome. Over the past decade, there has been increasing recognition that Stx is produced by additional Shigella species. We recently reported the presence and expression of stx genes in Shigella flexneri 2a clinical isolates. The toxin genes were carried by a new stx-encoding bacteriophage, and infection with these strains correlated with recent travel to Haiti or the Dominican Republic. In this study, we further explored the epidemiological link to this region by utilizing the French National Reference Centre for Escherichia coli, Shigella and Salmonella collection to survey the frequency of Stx-producing Shigella species isolated from French travellers returning from the Caribbean. Approximately 21% of the isolates tested were found to encode and produce Stx. These isolates included strains of S. flexneri 2a, S. flexneri Y, and S. dysenteriae 4. All of the travellers who were infected with Stx-producing Shigella had recently travelled to Haiti, the Dominican Republic, or French Guiana. Furthermore, whole genome sequencing showed that the toxin genes were encoded by a prophage that was highly identical to the phage that we identified in our previous study. These findings demonstrate that this new stx-encoding prophage is circulating within that geographical area, has spread to other continents, and is capable of spreading to multiple Shigella serogroups.

Preoperative and postoperative endotoxemia in children with congenital heart disease.

STUDY OBJECTIVES: Recent data indicate that increases in inflammatory cytokines are seen in patients with diverse cardiac diseases. However, the primary stimulus for cytokine secretion during cardiac illness remains unknown. Since bacterial endotoxin is a potent inducer of cytokines, we determined the incidence, magnitude, and clinical relevance of endotoxemia in children with congenital heart disease before and after surgical repair. DESIGN: A prospective, observational study. SETTING: A large, urban, university-affiliated, tertiary-care children's hospital. PATIENTS: Thirty children with a variety of congenital heart defects (median age, 59 days; median weight, 4.0 kg) were sequentially enrolled. INTERVENTIONS: Blood was sampled prior to surgery, and at 1, 8, 24, 48, and 72 h following cardiopulmonary bypass. Assays included plasma endotoxin, lipopolysaccharide-binding protein (LBP), and interleukin-6 (IL-6). MEASUREMENTS AND RESULTS: Twenty-nine of 30 patients (96%) had evidence of endotoxemia during the study period. Twelve of the 30 patients (40%) were significantly endotoxemic prior to surgery. LBP, a plasma marker that responds to bacteria and endotoxin, rose significantly following cardiopulmonary bypass, as did the plasma levels of IL-6. Fifteen of 30 patients met prospectively defined criteria for experiencing a severe hemodynamic disturbance in their postoperative course. These patients had significantly higher preoperative plasma LBP (p < 0.02) and plasma endotoxin levels (p < 0.05), compared to patients with less-severely disturbed hemodynamics. Mortality was 25% in patients with preoperative endotoxemia, compared with no mortality in patients who were not endotoxemic before surgery (p = 0.05). CONCLUSIONS: These data demonstrate that endotoxemia in children with congenital heart disease is more common than previously suspected, and is associated with clinical outcomes. We conclude that clinical trials targeting endotoxin will be necessary to determine if endotoxin is a causal, etiologic agent in the disease process.

Major intrahepatic venovenous fistulas after a modified Fontan operation.

After the Fontan operation, systemic venous hypertension drives transpulmonary blood flow. Owing to this physiology, there is a significant incidence of effusions, splanchnic congestion, and generalized edema. To attentuate the effusive problems, partial exclusion of the hepatic veins has been recently practiced by Jacobs and Norwood. This report concerns a patient we recently treated for profound progressive cyanosis due to an acquired intrahepatic venovenous shunt after a Fontan operation with partial hepatic vein exclusion.

Accurate numerical solutions for the frequency cross correlation of intensity fluctuations in a random medium.

The fourth-moment equation for the cross-frequency correlation of intensity fluctuations of a plane wave propagating in a random medium is solved numerically by using an adaptive grid method. A wide range of frequency ratios r and scattering strength parameters Gamma are considered, and approximate laws for the height and position of the peak of the covariance of intensities are obtained as functions of r and Gamma. Difficulties arising in the analytical solution of the fourth-moment equation are discussed.

Sex-related motor behavior: effects on social impressions and social cooperation.

Advances have been made recently in the measurement of sex-related motor behaviors (i.e., sex-typed ways of standing, sitting, walking, and gesturing). While these behaviors are an important dependent variable (e.g., as a measure of sex role), they can also be viewed as an independent variable. The present paper reports two experiments on the effect of sex-related motor behaviors. In the first, videotapes of males and females behaving in extremely sex-typed ways (both "masculine" and "feminine") were rated on a number of dimensions (e.g., sexual orientation, likeability). In the second, male and female confederates behaving in extremely sex-typed ways approached people and asked for their cooperation in filling out a long survey. Females showing "masculine" motor behavior were thought to be more masculine and unnatural appearing but also elicited significantly more cooperation than when acting feminine. Males showing "feminine" mannerisms were thought to be feminine, unnatural, unlikeable, unconfident, and probably homosexual, and elicited less actual cooperation than when acting masculine. In general, cross-sex motor behavior had mixed social effects with females and consistently negative social effects with males.

Sexual fantasy alternation.

The purpose of this study was (a) to assess the effect of fantasy alternation on sexual arousal, and (b) to assess the means by which fantasy alternation might alter sexual arousal patterns. The rate of alternation of heterosexual and homosexual masturbatory fantasies was manipulated in four adult males with sexual orientation confusion. The results showed that fantasy alternation can change the relative strength of physiologically measured sexual arousal patterns, but the direction and magnitude of the change seems unpredictable. The effect seems to be sensitive to the rapidity of fantasy alternation. Caution in the clinical use of the procedure with actual sexual deviants appears warranted.

Escape from freedom: Choosing not to choose in pigeons.

Preference for the availability of food-reinforcement alternatives was investigated with Rachlin and Green's (1972) concurrent-chains self-control paradigm. The terminal link of one chain made available a choice between immediate access to food for T seconds and delayed access to food for 4 seconds. The terminal link of the other chain provided only delayed access to food. When T was reduced to .25 seconds, pigeons began to select the delayed-access key in both terminal links. Even so, the pigeons strongly preferred constraint over choice. This effect could not be accounted for by differences in the actual amount of food obtained in the terminal links, by avoidance of the immediate-reinforcement key when not presented as part of a choice, or by avoidance of a multi-key terminal link. Rather, constraint was preferred over freedom. Apparently, the preference for choice is determined by the particular type of choice offered.