Experimental aerosolized guinea pig-adapted Zaire ebolavirus (variant: Mayinga) causes lethal pneumonia in guinea pigs.

Eight guinea pigs were aerosolized with guinea pig-adapted Zaire ebolavirus (variant: Mayinga) and developed lethal interstitial pneumonia that was distinct from lesions described in guinea pigs challenged subcutaneously, nonhuman primates challenged by the aerosol route, and natural infection in humans. Guinea pigs succumbed with significant pathologic changes primarily restricted to the lungs. Intracytoplasmic inclusion bodies were observed in many alveolar macrophages. Perivasculitis was noted within the lungs. These changes are unlike those of documented subcutaneously challenged guinea pigs and aerosolized filoviral infections in nonhuman primates and human cases. Similar to findings in subcutaneously challenged guinea pigs, there were only mild lesions in the liver and spleen. To our knowledge, this is the first report of aerosol challenge of guinea pigs with guinea pig-adapted Zaire ebolavirus (variant: Mayinga). Before choosing this model for use in aerosolized ebolavirus studies, scientists and pathologists should be aware that aerosolized guinea pig-adapted Zaire ebolavirus (variant: Mayinga) causes lethal pneumonia in guinea pigs.

Efficacies of BCG and vole bacillus (Mycobacterium microti) vaccines in preventing clinically apparent pulmonary tuberculosis in rabbits: a preliminary report.

Tuberculosis (TB) kills more people in the world today than any other infectious disease, and the number of drug-resistant Mycobacterium tuberculosis isolates is increasing. Vaccines, better than most of the currently available strains of bacille Calmette-Guérin (BCG), are urgently needed to control this disease. TB in rabbits resembles human TB more closely than TB in any other common laboratory animal and a most pertinent method of assessing vaccine efficacy is Lurie's tubercle count method in this species. Vaccinated and control rabbits were infected by aerosol with virulent human-type tubercle bacilli (H37Rv). At necropsy 5 weeks thereafter, the grossly visible primary tubercles in the entire lung were counted. A decrease in the number of such tubercles is a quantitative measure of vaccine efficacy: An effective vaccine prevents microscopic tubercles from growing to grossly visible (clinically apparent) size. The Pasteur substrain of BCG and two substrains of Mycobacterium microti (the vole bacillus) reduced the number of visible primary tubercles an average of 75%, whereas three other substrains of BCG and three other substrains of vole bacilli only reduced the number an average of 40%. These initial studies indicate that Lurie's tubercle-count method in rabbits is a precise way to choose the best available tuberculosis vaccines.

Practical skills and valued community outcomes: the next step in community-based education.

OBJECTIVES: Community-based medical education (CBE) has clear value. However, there are aspects of CBE where improvement is possible. First, communities do not generally receive valued outcomes in exchange for participation in the CBE process. Secondly, students are usually not trained to influence health in the community using methods that are realistic in busy clinical practice. DESIGN: A CBE rotation was designed to address these problems. Rotation activities were structured to facilitate development of a health programme desired by the community while giving students practical skills for later use. Working with community residents and health staff, sequential groups of students carried out, in turn, problem analysis, resource identification, planning and implementation activities aimed at establishing a community tuberculosis (TB) control programme. SETTING: The University of Natal in Durban, South Africa. SUBJECTS: Final-year medical students. RESULTS: At the end of the academic year, the TB control programme was approximately 60% in place, and 90% of TB patients cared for by the students were completing treatment. Overall, students rated the experience good for learning about health care in community settings and about methods for community health programme development. Student ratings were significantly higher for those groups whose activities brought them into greater contact with community residents. The 'real-time' nature of planning the sequential student groups' work created logistical problems and, as an isolated activity, the rotation had little impact on student attitudes toward community-based careers. CONCLUSIONS: Expanding the goals for CBE is both feasible and important. Further work should focus on refining designs for this next step in CBE.

Preliminary results of the Annual Survey of Deaf and Hard of Hearing Children and Youth in Puerto Rico: the first wave.

Preliminary findings are provided from the data collected in Puerto Rico through the Annual Survey of Deaf and Hard of Hearing Children and Youth during the 1997-1998 school year. The study was conducted as a part of an initiative to increase participation in the Annual Survey among the deaf and hard of hearing school-age population in Puerto Rico. Demographic, instructional, etiological, audiological, and communication data on 336 deaf and hard of hearing school age children were collected and summarized. The findings suggest the existence of a heterogeneous deaf community rather than the traditionally conceived homogeneous community. The discussion emphasizes the description of those attributes that suggest heterogeneity and the urgent need to continue to collect the kind of data gathered in the survey. The authors urge that Puerto Rican educators and researchers be stimulated to address the educational and health-related needs of Puerto Rico's deaf and hard of hearing school-age population.

Selective expression of estrogen receptor alpha and beta isoforms in human pituitary tumors.

The physiological effects of estrogen on the pituitary, including cellular proliferation and regulation of hormone synthesis, are mediated by the nuclear estrogen receptor (ER). The ER acts as a dimer to modulate gene transcription and contains specific functional domains encoded in different exons. Two separate, but related, forms of the receptor (ERalpha and ERbeta) exist, with distinct tissue and cell patterns of expression. Additional ER isoforms, generated by alternative messenger ribonucleic acid (mRNA) exon splicing, have been defined in several tissues and are postulated to play a role in tumorigenesis or in modulating the estrogen response. We examined 71 human pituitary adenomas of varying phenotypes and 6 normal pituitary specimens for ER mRNA forms by RT-PCR and hybridization blotting analysis. All prolactinomas (n = 14) contained ERalpha, and several contained ERbeta (5 of 14) mRNA. In comparison, 6 tumors that expressed PRL and GH expressed ERbeta (4 of 6) more frequently than ERalpha (3 of 6). ERbeta mRNA was also found more frequently in null cell (8 of 24 ERalpha and 14 of 24 ERbeta) and gonadotrope (13 of 21 ERalpha and 18 of 21 ERbeta) tumors. Additionally, ERbeta was found in 4 of 6 tumors that contained only GH, although ERalpha was not observed in this tumor type. Expression of the two ER forms within a tumor type was overlapping, but some tumors contained only 1 isoform. Expression of ERalpha mRNA splice variants also varied with cell type. All normal pituitaries contained ERalpha deletions of exon 4, 5, and 7, whereas only 2 of 6 samples contained the exon 2 deletion variant. Although the same ERalpha mRNA variants were observed among the various tumor types, the proportion of specific splice variants expressed varied. For example, most ER-positive prolactinomas expressed ERalpha variants with deletions of exon 2, 4, or 5, whereas gonadotropin tumors preferentially expressed the ERalpha exon 7 deletion variant. A novel ERbeta mRNA splice variant, missing exon 2, was observed in a majority of all ERbeta-positive tumors. Immunoblotting analysis of ERalpha and ERbeta proteins supported the mRNA results. Because ERalpha and ERbeta have different biological responses to selective ER modulators, and the ER deletion variants have biological effects distinct from those of the full-length ER, expression of these isoforms may influence the biological properties of these tumors and affect their ability to respond to estrogen and antiestrogen therapies.

The pathology of experimental anthrax in rabbits exposed by inhalation and subcutaneous inoculation.

OBJECTIVE: Although rhesus monkeys are considered to be an appropriate model for inhalational anthrax in humans, an alternative for vaccine and therapeutic efficacy studies is desirable. This study characterized the pathology of lethal anthrax in rabbits challenged by subcutaneous inoculation and aerosol exposure. MATERIALS AND METHODS: New Zealand white rabbits were exposed by subcutaneous inoculation or aerosol to lethal doses of Bacillus anthracis spores. RESULTS: The pathology of anthrax in rabbits exposed by either route was similar, with principal findings occurring in the spleen, lymph nodes, lungs, gastrointestinal tract, and adrenal glands. The cardinal changes were hemorrhage, edema, and necrosis, with bacilli and limited leukocytic infiltration. Features that depended on the route of exposure included mediastinitis in aerosol-exposed rabbits, a primary dermal lesion after subcutaneous inoculation, and differences in the pattern of lymph node involvement. Lesions observed in rabbits were comparable to those of inhalational anthrax in humans and rhesus monkeys. Noteworthy differences included the lack of leukocytic infiltration in brain and meningeal lesions, the relatively mild mediastinal lesions, and a lower incidence of anthrax-related pneumonia in rabbits compared with humans. These differences may be attributed to the greater susceptibility of rabbits to anthrax. Increased susceptibility is associated with both reduced leukocytic response to the bacilli and a more rapid progression to death, which further limits development of leukocytic infiltrates in response to the basic lesions of hemorrhage and necrosis. Primary pneumonic foci of inhalational anthrax, which may be influenced by preexisting pulmonary lesions in humans, were not observed in our rabbits, which were free of preexisting pulmonary disease. CONCLUSION: Anthrax in rabbits may provide a useful model for evaluating prophylaxis and therapy against inhalational anthrax in humans.

Differential gonadotropin-releasing hormone stimulation of rat luteinizing hormone subunit gene transcription by calcium influx and mitogen-activated protein kinase-signaling pathways.

Gonadotropin secretion and gene expression are differentially regulated by hypothalamic GnRH pulses by unknown mechanisms. GnRH stimulates calcium influx through L-type voltage-gated channels and activates phospholipase C, leading to increased protein kinase C (PKC) and mitogen-activated protein kinase activity. We found differential contributions of these pathways to GnRH-stimulated rat LH subunit transcription in pituitary gonadotropes and cell lines. Endogenous transcription of the alpha- and LHbeta-subunits in rat pituitary cells was stimulated by GnRH. Independent PKC activation by phorbol myristate acid stimulated only the alpha-subunit gene. In contrast, an L-channel antagonist (nimodipine) inhibited only LHbeta stimulation by GnRH, and an L-channel agonist (BayK 8644) stimulated only basal LHbeta transcription. GnRH induction of a rat alpha-subunit promoter construct in alphaT3 cells was unaffected by nimodipine or elimination of external calcium, while both treatments eliminated the LHbeta response. Application of a mitogen-activated kinase kinase (MEK) inhibitor (PD098059) decreased basal and GnRH-stimulated alpha-subunit promoter activity and had no effect on LHbeta promoter activity. In pituitary cells from mice bearing an LHbeta promoter-luciferase reporter transgene, GnRH stimulation was inhibited by nimodipine but not by PD098059. Thus, GnRH induction and basal control of the alpha-subunit gene seem to occur through the PKC/mitogen-activated protein kinase pathway, while induction of the LHbeta gene is dependent on calcium influx. Differential signaling from the same receptor may be a mechanism for preferential regulation of transcription.

Detection of interleukin-6 and interleukin-2 in serum of rhesus monkeys exposed to a nonlethal dose of staphylococcal enterotoxin B.

The immune response to a nonlethal dose of aerosolized staphylococcal enterotoxin B (SEB) was studied in nonhuman primates to define the potential human host response to a nonlethal exposure of SEB on the battlefield. Serum levels of the cytokines interleukin 2 (IL-2) and interleukin 6 (IL-6) increased significantly (p < 0.01) in six juvenile rhesus monkeys 4 hours after receiving a nonlethal, inhaled dose of SEB. The mean (+/-SD) peak serum levels of IL-2 and IL-6 were 63 +/- 39 units/ml and 514 +/- 234 pg/ml, respectively, post-SEB treatment. Tumor necrosis factor, known to be associated with SEB-mediated lethal toxic shock, was undetectable in all samples. gamma-Interferon concentrations were also elevated, but not significantly [p < 0.089]. Hence, elevated levels of IL-2 and IL-6 might be used as a serological marker for a nonlethal, incapacitating exposure to SEB.

Immunogenicity and efficacy against lethal aerosol staphylococcal enterotoxin B challenge in monkeys by intramuscular and respiratory delivery of proteosome-toxoid vaccines.

Staphylococcal enterotoxin B (SEB), a primary cause of food poisoning, is also a superantigen that can cause toxic shock after traumatic or surgical staphylococcal wound [correction of would] infections or viral influenza-associated staphylococcal superinfections or when aerosolized for use as a potential biologic warfare threat agent. Intranasal or intramuscular (i.m.) immunization with formalinized SEB toxoid formulated with meningococcal outer membrane protein proteosomes has previously been shown to be immunogenic and protective against lethal respiratory or parenteral SEB challenge in murine models of SEB intoxication. Here, it is demonstrated that immunization of nonhuman primates with the proteosome-SEB toxoid vaccine is safe, immunogenic, and protective against lethal aerosol challenge with 15 50% lethal doses of SEB. Monkeys (10 per group) were primed i.m. and given booster injections by either the i.m. or intratracheal route without adverse side effects. Anamnestic anti-SEB serum immunoglobulin G (IgG) responses were elicited in all monkeys, but strong IgA responses in sera and bronchial secretions were elicited both pre- and post-SEB challenge only in monkeys given booster injections intratracheally. The proteosome-SEB toxoid vaccine was efficacious by both routes in protecting 100% of monkeys against severe symptomatology and death from aerosolized-SEB intoxication. These data confirm the safety, immunogenicity, and efficacy in monkeys of parenteral and respiratory vaccination with the proteosome-SEB toxoid, thereby supporting clinical trials of this vaccine in humans. The safety and enhancement of both bronchial and systemic IgA and IgG responses by the proteosome vaccine delivered by a respiratory route are also encouraging for the development of mucosally delivered proteosome vaccines to protect against SEB and other toxic or infectious respiratory pathogens.

Experimental anthrax vaccines: efficacy of adjuvants combined with protective antigen against an aerosol Bacillus anthracis spore challenge in guinea pigs.

The efficacy of several human anthrax vaccine candidates comprised of different adjuvants together with Bacillus anthracis protective antigen (PA) was evaluated in guinea pigs challenged by an aerosol of virulent B. anthracis spores. The most efficacious vaccines tested were formulated with PA plus monophosphoryl lipid A (MPL) in a squalene/lecithin/Tween 80 emulsion (SLT) and PA plus the saponin QS-21. The PA+MPL in SLT vaccine, which was lyophilized and then reconstituted before use, demonstrated strong protective immunogenicity, even after storage for 2 years at 4 degrees C. The MPL component was required for maximum efficacy of the vaccine. Eliminating lyophilization of the vaccine did not diminish its protective efficacy. No significant alteration in efficacy was observed when PA was dialyzed against different buffers before preparation of vaccine. PA+MPL in SLT proved superior in efficacy to the licensed United States human anthrax vaccine in the guinea pig model.

Humoral immunity to aerosolized staphylococcal enterotoxin B (SEB), a superantigen, in monkeys vaccinated with SEB toxoid-containing microspheres.

Staphylococcal enterotoxin B (SEB) toxoid-containing microspheres were tested for efficacy in rhesus monkeys as a vaccine candidate for respiratory SEB toxicosis and toxic shock. Forty monkeys were randomly separated into 10 groups of four monkeys each: 9 groups were vaccinated with the microspheres via combinations of mucosal and nonmucosal routes, and 1 group served as nonvaccinated controls. Both vaccinated and nonvaccinated monkeys were then challenged with a high lethal dose of SEB aerosol. Monkeys primed with an intramuscular dose of the microspheres followed by an intratracheal booster all survived the SEB challenge. Overall, monkeys with an intratracheal booster generally had the highest antibody levels, which is consistent with their high survival rate and lower rate of illness. Protective immunity was correlated with antibody levels in both the circulation and the respiratory tract. The protection was not due to the depletion or anergy of SEB-reactive T cells, since SEB-induced proliferation in cultures of circulating lymphocytes was not significantly reduced after the microsphere vaccination. It is evident that the nonsurvivors did not die of systemic anaphylaxis or hypersensitivity because the monkeys did not die immediately after SEB challenge and there were no significant differences in histamine levels between the vaccinated and control monkeys before and after SEB challenge. The antibodies seemed to neutralize the SEB that got into the airway and the circulation.

Acoustic-phonetic context considerations for speech recognition testing of hearing-impaired listeners.

OBJECTIVE: To test for differences in the identification of consonants in carrier sentences versus in VCVs extracted from the sentences, as a function of listeners' hearing-loss categories: moderate, severe, profound. To examine whether pauses inserted in the sentences will facilitate identification of the consonants. DESIGN: Voiced stops and fricatives were identified by 11 listeners with moderate hearing losses and by 7 listeners with severe losses (between subjects design) for the conditions of consonants in sentences and in VCVs extracted from the sentences (repeated measures). Nine of these listeners also identified the consonants in the sentences with pauses. Six normal-hearing listeners were tested for the consonants in the extracted VCVs and the sentences. Voiceless stops and fricatives were identified by 4 listeners with profound losses, 18 with severe losses, and 8 with moderate losses (between subjects) for the conditions of extracted VCVs and the sentences (repeated measures). All listeners were selected on the basis of their hearing levels. RESULTS: The listeners with moderate to severe hearing loss identified the voiced stops and fricatives more poorly when the syllables were in the carrier sentences than when extracted. Insertion of the pauses in the sentence did not improve performance significantly. The normal hearing listeners showed no differences in consonant identification between the two conditions, perhaps due to "ceiling effects". The voiceless stops and fricatives were also identified more poorly when in the extracted VCVs than in the carrier sentences by other listeners with moderate to profound hearing loss. CONCLUSIONS: Listeners with moderate or greater hearing loss can show poorer identification of consonants that are embedded midway in carrier sentences than when the acoustically identical consonants are in VCVs extracted from the sentences. The performance reduction for the consonants in sentences is not relieved from insertion of brief artificial pauses in the sentences. Further research is needed determine whether hearing-impaired listeners' identification of consonants in target words of clinical word recognition tests is facilitated when the words are extracted from carrier phrases.

Temporal and spectral cue use for initial plosive voicing perception by hearing-impaired children and normal-hearing children and adults.

The influence of voice-onset time (VOT) and vowel-onset characteristics on the perception of the voicing contrast for initial plosive consonants was examined for hearing-impaired children, and normal-hearing children and adults. Listeners identified spoken 'DAD'--'TAD' stimuli controlled for VOT and vowel onset characteristics. Only six of 16 hearing-impaired children appropriately identified the exemplar DAD and TAD stimuli used as endpoints of VOT continua. For this group of six hearing-impaired children, a longer VOT than for the normal-hearing listeners was required to elicit /t/ rather than /d/ percepts. The VOT region of perceptual cross-over in labelling widened progressively from normal-hearing adults to normal-hearing children to hearing-impaired children. Generally, longer VOTs were required to yield /t/ perception in the context of the DAD vowel than with the TAD vowel. These 'vowel stem' effects on VOT boundary were inconsistent for the hearing-impaired children, and weaker for the normal-hearing children than for the adults. These spoken stimuli produced results for VOT cue use that generally parallel those obtained in studies with synthetic stimuli.

Immunity and responses of circulating leukocytes and lymphocytes in monkeys to aerosolized staphylococcal enterotoxin B.

Rhesus monkeys immunized intramuscularly or orally with staphylococcal enterotoxin B (SEB) toxoid or SEB toxoid incorporated in microspheres made of poly(DL-lactide-co-glycolide) were challenged with a lethal dose of aerosolized SEB to study their immunity and cellular responses in the circulation. It was found that circulating antibodies play a critical role in preventing SEB from triggering toxicosis. Monkeys with high levels of antibodies survived, while those with low levels underwent 2 to 3 days of toxicosis and died. Intramuscular immunization induced high levels and oral immunization induced low levels of antibodies. The circulating antibodies in surviving monkeys decreased dramatically within 20 min and started to rebound at 90 min after SEB challenge. At 90 min, the dying monkeys showed in the circulation a dramatic increase of polymorphonuclear leukocytes and decreases of NK cells and monocytes (CD16 and CD56 markers) as well as of lymphocytes with HLA-DR, CD2, CD8, and IL2R alpha (CD25) markers. The number of polymorphonuclear leukocytes showed an inverse correlation with the numbers of monocytes and various lymphocyte subpopulations which, except for IL-2R, CD16, and CD56(+) cells, showed a direct correlation with one another. The changes in the populations of leukocytes, monocytes, NK cells, and lymphocytes seem to be an indication of initial toxicosis; however, the roles of these cells in toxicosis and death remain to be defined.

VCVs vs CVCs for stop/fricative distinctions by hearing-impaired and normal-hearing listeners.

Moderately to profoundly hearing-impaired (n = 30) and normal-hearing (n = 6) listeners identified [p, k, t, f, theta, s] in [symbol; see text], and [symbol; see text]s tokens extracted from spoken sentences. The [symbol; see text]s were also identified in the sentences. The hearing-impaired group distinguished stop/fricative manner more poorly for [symbol; see text] in sentences than when extracted. Further, the group's performance for extracted [symbol; see text] was poorer than for extracted [symbol; see text] and [symbol; see text]. For the normal-hearing group, consonant identification was similar among the syllable and sentence contexts.

Child functional independence and maternal psychosocial stress as risk factors threatening adaptation in mothers of physically or sensorially handicapped children.

This study investigated the contribution of child functional independence and maternal psychosocial stress to the adaptation of 119 mothers. Each mother had a child, aged 2-18 years, with a physical or sensory disability. Multiple dimensions of each construct were measured through self-report. Child functional independence did not uniquely explain variation in mothers' adaptation. However, maternal stress was uniquely associated with maternal mental health, but not physical health or social functioning, even when controlling for demographic status, disability type, and functional independence. Daily hassles and handicap-related psychosocial stress in particular put mothers at risk for reporting mental health problems.