Development and Evaluation of an Interactive CD-ROM Refusal Skills Program to Prevent Youth Substance Use: “Refuse to Use”

An interactive CD-ROM program designed to reduce adolescent substance use was developed and evaluated. The program uses video vignettes to teach refusal skills and socially acceptable responses to substance use situations, specifically offers of marijuana. In a randomized pretest-to-posttest experiment with 74 public school students from six classes in three high schools, significant changes were observed at posttest on (1) the adolescent's personal efficacy to refuse the offer of marijuana, (2) the adolescent's intention to refuse marijuana if offered, and (3) the adolescent's perceptions of the social norms associated with substance use and the importance of respecting another's decision to refuse a drug offer. In addition, adolescents in the treatment condition were able to recall approximately 50% of the portrayed refusal strategies. Findings are discussed with regard to the potential benefits of an interactive multimedia approach for conducting substance use interventions.     

Rotavirus survival on human hands and transfer of infectious virus to animate and nonporous inanimate surfaces.

We tested the survival of the Wa strain of human rotavirus on the hands of volunteers and also studied infectious virus transfer between animate and inanimate (stainless steel disks) surfaces. The virus was diluted in a 10% suspension of feces, and 10 microliters (1 X 10(3) to 4 X 10(4) PFU) was placed on each of the four fingerpads of the left hand. One milliliter of 20% tryptose phosphate broth in Earle balanced salt solution was used for virus elution from each fingerpad, and the hands were disinfected with 70% ethanol before they were washed with an antiseptic soap and water. At 20, 60, and 260 min after inoculation, approximately 57, 43, and 7%, respectively, of the input infectious virus could be recovered. For virus transfer, the inoculum (2 X 10(4) to 8 X 10(4) PFU) was allowed to dry, and the donor surface was kept in contact with the recipient surface for 10 s at a pressure of approximately 1 kg/cm2. At 20 and 60 min after virus inoculation, 16.1 and 1.8%, respectively, of the input infectious virus could be transferred from the contaminated hand to a clean disk; when a clean hand was pressed against a contaminated disk, virus transfer was 16.8 and 1.6%, respectively. Contact between a contaminated and a clean hand 20 and 60 min after virus inoculation resulted in the transfer of 6.6 and 2.8%, respectively, of the input infectious virus. These findings indicate the potential vehicular role for human hands in the spread of rotaviral infections.     

Exotoxin activity associated with the Legionnaires disease bacterium.

Hemolysis occurred around growth of the Legionnaires disease bacterium on supplemented Mueller-Hinton agar containing sterile defibrinated blood from each of five mammalian species. Hemolysis was most pronounced with guinea pig or rabbit blood, was less intense with horse or sheep blood, and was slight with blood from a human donor. Sterile filtrates of allantoic fluid from embryonated hen's eggs that had been infected with this organism displayed hemolytic activity in a radial hemolysis assay with guinea pig cells in agar. Growth of the Legionnaires disease bacterium on F-G agar with 5% hen's egg yolk was surrounded by a zone of clearing and more circumscribed zones of iridescence and increased opacity on and in the medium. Attempts to detect activity analogous to that of Escherichia coli heat-labile or heat-stable enterotoxin in allantoic fluid from infected eggs or in cultures of the Legionnaires disease bacterium were not successful.     

Effect of pituitary gonadotrophins on proliferation of primary cultures of human ovarian stroma

Proliferation of ovarian stromal cells is a common phenomenon in peri- and post-menopausal ovaries. It is generally assumed to be secondary to the rise in circulating gonadotrophins at the menopause, though the process by which it occurs is poorly understood. This study aimed to examine the effect of menopausal levels of pituitary gonadotrophins on the growth of primary cultures of ovarian stroma. A culture system was developed using primary explants of ovarian stroma on a collagen substrate. The effect of follicle stimulating hormone (FSH; 10(-5) g/l) and luteinizing hormone (LH; 10(-5) g/l) on the proliferation of cultures derived from the cortices and medullae of ten ovaries was evaluated using a dual radiothymidine labelling technique. FSH was stimulatory to cortical cultures from 9/10 ovaries and medullary cultures from 7/10 ovaries, while LH was stimulatory to cortical cultures from 6/9 ovaries and medullary cultures from 5/10 ovaries. The responsiveness of the cultures did not correlate with the degree of hyperplasia in vivo. This study demonstrates that pituitary gonadotrophins may modulate the growth of stromal cells in culture, and thus may play a role in the process whereby stromal proliferation occurs in peri- and post-menopausal ovaries.     

Evidence for the phagocytic transport of intestinal particles in dogs and rats.

Fluorescent latex beads of two different colors were implanted into separate intestinal segments in individual dogs and rats. Mesenteric lymph node phagocytes subsequently contained multiple beads of one or the other color but rarely both colors, indicating that intestinal phagocytes transported the latex beads to the draining lymph node. Fluorescent labeled Escherichia coli was implanted into rat ligated intestinal segments, and rare mesenteric lymph node phagocytes subsequently contained fluorescent bacteria, suggesting that intestinal bacteria might be transported in the same manner as inert latex beads.     

Epitope mapping of a protective monoclonal antibody against Pneumocystis carinii with shared reactivity to Streptococcus pneumoniae surface antigen PspA

Pneumocystis carinii is an opportunistic fungal pathogen that causes pneumonia in the immunocompromised host. A protective monoclonal antibody (MAb) termed 4F11 generated against mouse-derived P. carinii was shown by indirect immunofluorescence assay (IFA) to bind surface antigens of P. carinii derived from multiple host species, including humans. We have identified multiple epitopes recognized by MAb 4F11 in two recombinant mouse P. carinii antigens. The epitopes mapped have similar proline content and positive charge distribution. The consensus 8-mer epitope recognized by MAb 4F11 is K/RPA/RPK/QPA/TP. Immune sera raised against intact mouse P. carinii recognized native antigens affinity purified with MAb 4F11 and a recombinant antigen reactive with MAb 4F11. Database searches for short, nearly exact matches to the mapped MAb 4F11 epitopes identified a bacterial surface antigen, Streptococcus pneumoniae PspA, with a similar proline-rich region. In an IFA, MAb 4F11 detected antigens on the S. pneumoniae surface, and Western blotting identified a protein in S. pneumoniae lysates consistent with the M(r) of PspA. A fragment of the S. pneumoniae PspA gene was cloned and sequenced, and the deduced amino acid sequence contained a region with strong similarity to the MAb 4F11 epitopes identified in P. carinii. The PspA recombinant polypeptide was recognized by MAb 4F11 in a Western blot. The ability of MAb 4F11 to recognize similar proline-rich epitopes may explain its ability to recognize P. carinii derived from multiple hosts and will permit testing of the epitopes recognized by this antibody in immunization against P. carinii.     

Sexually dimorphic expression of protease nexin-1 and vanin-1 in the developing mouse gonad prior to overt differentiation suggests a role in mammalian sexual development

The mammalian sex-determining pathway is controlled by the presence or absence of SRY expression in the embryonic gonad. Expression of SRY in males is believed to initiate a pathway of gene expression resulting in testis development. In the absence of SRY, ovary development ensues. Several genes have now been placed in this pathway but our understanding of it is far from complete and several functional classes of protein appear to be absent. Sex-determining genes frequently exhibit sexually dimorphic patterns of expression in the developing gonad both before and after overt differentiation of the testis or ovary. In order to identify additional sex-determining or gonadal differentiation genes we have examined gene expression in the developing gonads of the mouse using cDNA microarrays constructed from a normalized urogenital ridge library. We screened for genes exhibiting sexually dimorphic patterns of expression in the gonad at 12.5 and 13.5 days post-coitum, after overt gonad differentiation, by comparing complex cDNA probes derived from male and female gonadal tissue at these stages on micro-arrays. Using in situ hybridization analysis we show here that two genes identified by this screen, protease nexin-1 (Pn-1) and vanin-1 (Vnn1), exhibit male-specific expression prior to overt gonadal differentiation and are detected in the somatic portion of the developing gonad, suggesting a possible direct link to the testis-determining pathway for both genes.     

Adhesion in vitro and in vivo associated with an adhesive antigen (F41) produced by a K99 mutant of the reference strain Escherichia coli B41.

A K99-negative mutant of the K99 reference strain Escherichia coli B41 (O101:K99) was isolated (strain B41M). It did not react with OK antiserum to a K12 K99+ recombinant or with OK antiserum to K99-positive organisms from the O8, O20, or O64 serogroups, but it did react with OK antiserum to K99-positive organisms from the O101 and O9 serogroups. The mutant hemagglutinated sheep erythrocytes and attached in vitro to calf enterocytes when cultured at 37 degrees C but not when grown at 18 degrees C. Attachment was mannose resistant but susceptible to heating and formaldehyde. These properties were associated with the presence of fimbriae. The isolated hemagglutinin migrated to the anode in immunoelectrophoresis experiments, competitively inhibited attachment of strain B41M to calf enterocytes, and could be demonstrated adhering to these cells in vitro by indirect immunofluorescent staining. The anionic hemagglutinin is referred to provisionally as F41. Germfree piglets infected with strain B41M developed diarrhea within 16 h. Scanning electron microscopy showed groups of bacteria adherent to the microvilli of villous enterocytes. Indirect immunofluorescent staining demonstrated the presence of F41 antigen in vivo.     

Fast, anticipatory smooth-pursuit eye movements appear to depend on a short-term store

Anticipatory smooth pursuit before the expected appearance of a moving target can reduce the initial retinal blur caused by the 100-ms delay of visual feedback. Humans, though, can only voluntarily generate smooth velocities up to about 5°/s without a moving target. However, previous experiments have shown that repetitive brief presentations of a moving target every few seconds appear to charge an internal store, the contents of which can later be released to generate higher velocity anticipatory movements. This store’s longevity was assessed here by repetitively presenting a moving target for 500 ms at different known intervals up to 7.2 s. Target motion at 25°/s or 50°/s was tested, with presentations in alternate directions or the same direction. Anticipatory velocity, measured 100 ms after target onset, decreased with increasing interval for all target motion conditions. A decrease was still seen when accurate timing cues were given before each presentation, suggesting that the drive for anticipatory pursuit is held in a short-term store lasting a few seconds which can enhance the low velocities produced by volition alone. The results also demonstrate that high-velocity anticipatory pursuit helps to overcome the temporal delays in the system and allows target velocity to be matched at an earlier time. Received: 27 August 1997 / Accepted: 22 December 1997