Harnessing alveolar macrophages for sustained mucosal T-cell recall confers long-term protection to mice against lethal influenza challenge without clinical disease.

Vaccines that induce T cells, which recognize conserved viral proteins, could confer universal protection against seasonal and pandemic influenza strains. An effective vaccine should generate sufficient mucosal T cells to ensure rapid viral control before clinical disease. However, T cells may also cause lung injury in influenza, so this approach carries inherent risks. Here we describe intranasal immunization of mice with a lentiviral vector expressing influenza nucleoprotein (NP), together with an NFκB activator, which transduces over 75% of alveolar macrophages (AM). This strategy recalls and expands NP-specific CD8+ T cells in the lung and airway of mice that have been immunized subcutaneously, or previously exposed to influenza. Granzyme B-high, lung-resident T-cell populations persist for at least 4 months and can control a lethal influenza challenge without harmful cytokine responses, weight loss, or lung injury. These data demonstrate that AM can be harnessed as effective antigen-presenting cells for influenza vaccination.

Nucleophosmin is a novel Bax chaperone that regulates apoptotic cell death.

The proapoptotic B-cell lymphoma-2 family protein Bax is a key regulatory point in the intrinsic apoptotic pathway. However, the factors controlling the process of Bax activation and translocation to mitochondria have yet to be fully identified and characterized. We performed affinity chromatography using peptides corresponding to the mitochondrial-targeting region of Bax, which is normally sequestered within the inactive structure. The molecular chaperone nucleophosmin was identified as a novel Bax-binding protein by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Reciprocal co-immunoprecipitation and proximity assays confirmed the Bax-nucleophosmin protein-protein interaction and verified that nucleophosmin only bound to activated conformationally altered Bax. Confocal microscopy in a cell-based apoptosis model, demonstrated that nucleophosmin translocation from nucleolus to cytosol preceded Bax movement. Specific knockdown of nucleophosmin expression using RNAi attenuated apoptosis as measured by mitochondrial cytochrome c release and activation of the caspase cascade. In a mouse model of ischaemic stroke, subcellular fractionation studies verified that nucleophosmin translocation occurred within 3 h, at a time before Bax translocation but after Bax conformational changes have occurred. Thus, we have elucidated a novel molecular mechanism whereby Bax becomes activated and translocates to the mitochondria to orchestrate mitochondrial dysfunction and apoptotic cell death, which opens new avenues for therapeutic intervention.

Adolescent risk behavior and the influence of parents and education.

BACKGROUND: Adolescent involvement with alcohol, drugs, tobacco, sexual relationships, and gang violence begins at increasingly younger ages. Awareness of the dangers and consequences of risk-taking behavior has not had a profound or lasting impact on adolescent behavior, and there appears to be no relation between risk behavior and general knowledge concerning these topics. METHODS: Using paired anonymous questionnaires, we surveyed 215 seventh-grade students and their parents about their experience with and attitudes toward adolescent risk-taking behaviors. The results of each student questionnaire were compared with results of his or her own parents. The survey instrument contained questions concerning tobacco, alcohol, and drug use, sexual activity, gang membership, general knowledge concerning these topics, and parental guidance given. Data were analyzed using the chi2 test of significance. RESULTS: Parent and student recollection of issues discussed and guidance given differed widely, as did the students' understanding of their parents' guidance. Factors found to have a meaningful impact on the reduction of risk behavior in the adolescent population were (1) students perceiving a satisfactory relationship with their parents, and (2) parents successfully communicating their expectations regarding these behaviors to their children. CONCLUSIONS: Parental direction has a powerful effect on the reduction of risk behavior in young adolescents. A limited ability for abstract reasoning during early adolescence requires clear anticipatory guidance by parents and an active effort to maintain communication in the child-parent relationship.

Appropriate roles of cardiac troponins in evaluating patients with chest pain.

BACKGROUND: Diagnosis of acute myocardial infarction relies upon the clinical history, interpretation of the electrocardiogram, and measurement of serum levels of cardiac enzymes. Newer biochemical markers of myocardial injury, such as cardiac troponin I and cardiac troponin T, are now being used instead of or along with the standard markers, the MB isoenzyme of creatine kinase (CK-MB) and lactate dehydrogenase. METHODS: We performed a MEDLINE literature search (1987 to 1997) using the key words "troponin I," "troponin T," and "acute myocardial infarction." We reviewed selected articles related to the diagnostic and prognostic usefulness of these cardiac markers in evaluating patients with suspected myocardial infarction. RESULTS: We found that (1) troponin I is a better cardiac marker than CK-MB for myocardial infarction because it is equally sensitive yet more specific for myocardial injury; (2) troponin T is a relatively poorer cardiac marker than CK-MB because it is less sensitive and less specific for myocardial injury; and (3) both troponin I and troponin T may be used as independent prognosticators of future cardiac events. CONCLUSIONS: Troponin I is a sensitive and specific marker for myocardial injury and can be used to predict the likelihood of future cardiac events. It is not much more expensive to measure than CK-MB. Overall, troponin I is a better cardiac marker than CK-MB and should become the preferred cardiac enzyme when evaluating patients with suspected myocardial infarction.

Comparison of ultrasound examination with bone scintiscan in the diagnosis of stress fractures.

BACKGROUND: We wanted to compare an ultrasound examination with the bone scintiscan to diagnose stress fractures. METHODS: Using the bone scintiscan as the reference standard, we conducted a prospective, double-blind study of 78 patients (87 percent were men, mean age 24 years) referred for bone scintiscan to rule out tibial stress fractures. After the participants were injected with radionuclide, we examined each tibia once using ultrasound adjusted for an active intensity of 2.0 W/cm2 and again with the wand turned off. The patient was blinded to the mode used. The patient's response to the ultrasound was considered positive if the patient reported pain as the wand passed over the tibia. A bone scintiscan was considered positive according to the criteria of Zwas. One sonography technician performed all examinations; both he and the nuclear medicine department were blinded to the other's findings. The final results were tabulated by a third, uninvolved party. A positive correlation between the scintiscan and ultrasound examination consisted of pain with active ultrasound and any degree of stress fracture in any part of the same tibia as found on the bone scintiscan. RESULTS: Thirty-five stress fractures were found on bone scintiscan, whereas only 15 were detected by ultrasound examination (sensitivity 43 percent). With ultrasound testing there were 22 false positives (specificity 49 percent) and 20 false negatives. These findings resulted in a positive predictive value of 41 percent and a negative predictive value of 51 percent. CONCLUSION: Ultrasound is not reliable in the diagnosis of tibial stress fractures. Bone scintiscan remains the test of choice.

Zinc deprivation and zinc repletion: effect on the response of rats to infection with Strongyloides ratti.

The course of a subcutaneous weight-related infection with Strongyloides ratti was followed in rats fed diets containing either 3 mg Zn/kg diet [zinc deficient (Zn-)] or 40 mg Zn/kg diet [zinc adequate (Zn+)]. At 19 d postinfection (dpi) the proportions of larvae persisting in the intestines as adult worms were 52 +/- 2% (means +/- SEM) for Zn-, 39.5 +/- 2.5% for pair-fed Zn- (Zn-PF), and 31.6 +/- 3.2% for Zn+ (p less than 0.001, analysis of variance); some Zn- rats were then transferred to the zinc-adequate diet [This was the zinc-repleted group (ZnR).] Both groups retained a group of pair-fed controls (Zn-PF and ZnRPF). Between 19 and 28 dpi ZnR animals gained weight faster than did Zn- animals and had heavier thymuses relative to body weight. Zinc deficiency enhances the establishment of S ratti larvae in the intestine of rats and alters the characteristics of intestinal expulsion of the nematodes; however, spontaneous cure was achieved by 38 dpi in both Zn- and control groups.

Kinetics of Nippostrongylus brasiliensis infection in the zinc-deficient rat.

The role of zinc (Zn) in the immunological expulsion of the nematode Nippostrongylus brasiliensis (Nb) from the small intestine of the rat was investigated. Three groups of 28 rats each were fed a basal diet providing either 3 mg Zn/kg for the zinc-deficient group (-Zn) or 40 mg Zn/kg for ad libitum-fed and pair-fed controls. After 6 wk each group was divided into two equal subgroups and infected with either 1000 or 4000 infective Nb larvae/rat. The -Zn rats showed significant reductions (P less than 0.001) in food intake, weight gain and food conversion efficiency when compared to the rats fed ad libitum but not when compared to the pair-fed controls. Plasma zinc concentration in the -Zn rats (0.50 microgram/ml) was significantly lower than in both ad libitum-fed (1.33 micrograms/ml) and pair-fed (1.45 micrograms/ml) controls (P less than 0.001). The recovery of worms from the rats 3, 7 and 12 d postinfection was similar for the corresponding day and dose of infection in all groups. Expulsion was almost complete in all groups by 12 d post-infection. There were no significant differences in size and fecundity of worms recovered from the different groups of rats on 7 d postinfection. However, over the whole period of infection, the -Zn rats excreted significantly more parasite eggs than did controls (P less than 0.001). These results indicate that although zinc deficiency affected growth performance of the rats, it did not affect the establishment or expulsion of Nb. Impairment of the immune response of the zinc-deficient rat was manifested only by a significant increase in the number of parasite eggs excreted in feces.

Production disease control: three dairy herd case studies in NE Scotland.

Three cases of dairy herds affected by production disease (infertility, calf scours and low milk yield) were carried out. The value of blood analysis in establishing a diagnosis and a dietary supplement of molasses in correcting the production problems is illustrated.

The effects of pronethalol and propranolol on the coronary circulation of the dog.

1. The actions of pronethalol and propranolol have been studied to see if there was any relationship between the reduction in coronary flow and any other cardiovascular action they have.2. The experiments were carried out in anaesthetized open chest dogs. Measurements included central arterial, left and right venous or atrial pressures, heart rate, ventricular size and stroke volume, intra-ventricular pressures, total left coronary flow, arterial and coronary sinus blood pO(2). The pressure-time index (PTI) and maximum rate of isovolumetric contraction (dp/dt) were obtained from these records.3. It was concluded that, in these experiments, the reduction in coronary flow produced by pronethalol and propranolol was not directly related to a decrease in perfusion pressure, a raised venous pressure, the increase in ventricular volume and hence wall tension, the decrease in heart rate, or to the increased duration of systole.4. The PTI and dp/dt were always reduced at the same time as the coronary flow. These findings are discussed.5. Studies of the effects of sympathetic stimulation, of phentolamine, of reduced arterial oxygen tension and electrical pacing of the heart, all after beta-blockade, did not support the suggestion that the reduction in coronary flow after beta-blockade was due to the unmasking of an active vasoconstriction.