The leptospiral major outer membrane protein LipL32 is a lipoprotein expressed during mammalian infection.

We report the cloning of the gene encoding the 32-kDa lipoprotein, designated LipL32, the most prominent protein in the leptospiral protein profile. We obtained the N-terminal amino acid sequence of a staphylococcal V8 proteolytic-digest fragment to design an oligonucleotide probe. A Lambda-Zap II library containing EcoRI fragments of Leptospira kirschneri DNA was screened, and a 5.0-kb DNA fragment which contained the entire structural lipL32 gene was identified. Several lines of evidence indicate that LipL32 is lipid modified in a manner similar to that of other procaryotic lipoproteins. The deduced amino acid sequence of LipL32 would encode a 272-amino-acid polypeptide with a 19-amino-acid signal peptide, followed by a lipoprotein signal peptidase cleavage site. LipL32 is intrinsically labeled during incubation of L. kirschneri in media containing [(3)H]palmitate. The linkage of palmitate and the amino-terminal cysteine of LipL32 is acid labile. LipL32 is completely solubilized by Triton X-114 extraction of L. kirschneri; phase separation results in partitioning of LipL32 exclusively into the hydrophobic, detergent phase, indicating that it is a component of the leptospiral outer membrane. CaCl(2) (20 mM) must be present during phase separation for recovery of LipL32. LipL32 is expressed not only during cultivation but also during mammalian infection. Immunohistochemistry demonstrated intense LipL32 reactivity with L. kirschneri infecting proximal tubules of hamster kidneys. LipL32 is also a prominent immunogen during human leptospirosis. The sequence and expression of LipL32 is highly conserved among pathogenic Leptospira species. These findings indicate that LipL32 may be important in the pathogenesis, diagnosis, and prevention of leptospirosis.

Expression and distribution of leptospiral outer membrane components during renal infection of hamsters.

The outer membrane of pathogenic Leptospira species grown in culture media contains lipopolysaccharide (LPS), a porin (OmpL1), and several lipoproteins, including LipL36 and LipL41. The purpose of this study was to characterize the expression and distribution of these outer membrane antigens during renal infection. Hamsters were challenged with host-derived Leptospira kirschneri to generate sera which contained antibodies to antigens expressed in vivo. Immunoblotting performed with sera from animals challenged with these host-derived organisms demonstrated reactivity with OmpL1, LipL41, and several other proteins but not with LipL36. Although LipL36 is a prominent outer membrane antigen of cultivated L. kirschneri, its expression also could not be detected in infected hamster kidney tissue by immunohistochemistry, indicating that expression of this protein is down-regulated in vivo. In contrast, LPS, OmpL1, and LipL41 were demonstrated on organisms colonizing the lumen of proximal convoluted renal tubules at both 10 and 28 days postinfection. Tubular epithelial cells around the luminal colonies had fine granular cytoplasmic LPS. When the cellular inflammatory response was present in the renal interstitium at 28 days postinfection, LPS and OmpL1 were also detectable within interstitial phagocytes. These data establish that outer membrane components expressed during infection have roles in the induction and persistence of leptospiral interstitial nephritis.

A nuclear magnetic resonance investigation of the upper airways in ferrets. I. Effects of histamine and methacholine.

Alterations induced in the upper airways of ferrets by intranasal provocation with methacholine (MC) and histamine (HS) were monitored using proton magnetic resonance imaging (MRI) and spin-spin relaxation rate (R2) measurements. Both MC and HS cause a significant increase in the MRI signal intensity and a decrease in R2 in the nasal turbinates. A dose-dependent response is observed for 20 to 315 nmol of HS, with a maximum increase in intensity of ca. 50% occurring above 80 nmol. A single unilateral challenge with MC yields a 62 +/- 3% increase in intensity. Control animals (saline-treated) show little change in image intensity. MC and HS cause decreases in the proton R2 by -27.0 +/- 5.5% and -17.2 +/- 4.3%, respectively. These data are indicative of an accumulation of fluid in the nasal airways. MRI provides an effective means to monitor changes in the nasal airways which occur as a result of pharmacological treatment.

Familial correlates of sexually active pregnant and nonpregnant adolescents.

The relationship of familial, demographic, and individual characteristics to the probability of pregnancy was examined among 124 sexually active adolescent females. Logistic regression analyses revealed that adolescent pregnancy status was a function of a combination of demographic and familial variables. Adolescents who were pregnant at the time of the study perceived their families as having low levels of family strength, perceived communication with parents as closed, came from homes characterized by family fragmentation (i.e., only one parent or no parent living in the home), came from low-income households, were unlikely to use any method of birth control, and were more likely to be married than their nonpregnant counterparts.

PIP: The differences in demographic characteristics, sexual practices, perceptions of family functioning, and individual factors among pregnant and nonpregnant adolescents were studied. 124 sexually active adolescent Caucasian females aged 12-19 years from an Arkansas clinic of which 57% were pregnant, participated in a nonrandom sample in 1988-89. 62.1% were from disrupted families (39.5% divorced, 12.9% remarried, and 9.7% widowed). Family disruption was higher among the pregnant sample (72% vs. 50.8%). 16.9% of the total sample were high school dropouts, but the majority were in the pregnant sample (28% vs. 5%). 91% of the pregnant sample had a family income of $20,000 vs. 66% of the nonpregnant sample. The procedures and instruments used are described. The following questionnaires were involved: 1) a demographic questionnaire for age, race, educational and marital status, parents' marital status, and socioeconomic status; 2) a sexual history questionnaire for pregnancy status, use of birth control, prior pregnancies and outcomes, and frequency of sexual activity; and 3) the Family Adaptability and Cohesion Evaluation Scale, the Family Strengths Questionnaire, the Parent Communication Scale, and the Adolescent Self-Esteem Scale. Stepwise logistic regression and chi square tests were used to predict pregnancy status. 6 variables out of 11 were significantly related to pregnancy status: lower perception of family strengths, problems with parent communication, married, low family income, birth control, and single parent or no parent family composition. 80% of pregnant and nonpregnant teens were predicted. The mean for perception of family strengths for pregnant vs. nonpregnant adolescents was 33.29 vs. 39.87, which means for pregnant teens a perception of a lack of pride and harmony in their families. Lower scores were also evident on the Parent Communication Scale (-1.22 vs. 2.62). Although not significant, pregnant adolescents saw their families as flexible but not very cohesive and had lower self-esteem scores. Nonpregnant adolescents were more likely to use birth control than pregnant adolescents. The results support prior findings with some variation in the effect of parent and child communication, and insignificant effects of perception of family adaptability, and self-esteem. The limitations are the lack of generalizability to other regions, and the model itself which did not assess familial factors such as parental control or other developmental factors such as self-worth. Causality is not determined.

Kinins are generated in nasal secretions during influenza A infections in ferrets.

Infection of ferrets with influenza A virus results in a disease syndrome that is similar to that observed in humans. To examine the pathophysiology of this disease, ferrets were challenged with either H1N1 influenza virus or placebo. Sign scores and rectal temperatures were recorded periodically during the 9 days after infection. Nasal lavages were also collected during this time period and the content of kinins, histamine, cells, and total protein in these lavages was assessed. In infected animals (n = 17) compared to healthy controls (n = 14), sign scores were first significantly elevated at 30 h postinfection. Sign scores peaked at 48 to 72 h postinfection and then slowly declined, although they remained significantly elevated up to 168 h postinfection. Kinin levels were significantly correlated with signs. Associated with increased sign scores and kinins, elevations were observed in the levels of total protein and cells in nasal lavages of infected animals. In contrast to the increases in kinin levels that were observed during influenza infections, histamine concentrations in nasal lavages did not change in response to infection. We conclude that kinins are generated in nasal secretions during influenza A infections and that these potent vasoactive peptides may contribute to the symptomatology of such infections. The study of influenza infections in ferrets provides a convenient animal model in which to evaluate further the role of kinins in the pathogenesis of upper respiratory tract infections.

Early adolescent age and gender differences in patterns of emotional self-disclosure to parents and friends.

This study explored adolescent age and gender differences in patterns of emotional self-disclosure to parents and friends. The sample consisted of 174 junior high school students between the ages of 12 and 15. Results revealed that females exhibited greater emotional self-disclosure to parents and peers than did males, and that emotional self-disclosure to friends was greatest among older adolescents. In addition, while younger adolescents preferred to disclose information about their emotional state to parents, older adolescents chose friends. Exploratory hierarchical regression analyses revealed that emotional disclosure to parents was most strongly associated with adolescent perceptions of the openness of family communication, family cohesion, and satisfaction with family relationships. Emotional disclosure to friends was associated with adolescent self-esteem in the peer context and identity development. The results are discussed in terms of the complementary socializing processes that may operate within the contexts of family and friends.

Grade, pubertal status, and gender-related variations in conflictual issues among adolescents.

The purpose of this study was to describe adolescent perceptions of conflictual family issues, and to ascertain if the intensity of these issues is associated with adolescent grade in school, pubertal status, and gender. The sample was comprised of 279 junior high and senior high school students. Each participant completed a self-report measure of pubertal status, a demographic questionnaire, and the Issues Checklist. Principal factor analysis with varimax rotation of the Issues Checklist resulted in the retention of four factors accounting for 71.59% of the variance. Stepwise regression analyses were conducted for each emergent factor with grade in school, pubertal status, and gender serving as predictors. The results of these analyses indicated that the intensity of School Issues and Household Behavior Issues is greater among seventh and ninth graders than among eleventh graders. Self-Responsibility Issues were perceived as being most intense among transpubertal adolescents. Finally, boys perceived more intense conflict over Persistent Issues and Concerns than did girls.