The relationship between flesh quality and numbers of Kudoa thyrsites plasmodia and spores in farmed Atlantic salmon, Salmo salar L.

Atlantic salmon, Salmo salar L., were exposed to Kudoa thyrsites (Myxozoa, Myxosporea)-containing sea water for 15 months, and then harvested and assessed for parasite burden and fillet quality. At harvest, parasites were enumerated in muscle samples from a variety of somatic and opercular sites, and mean counts were determined for each fish. After 6 days storage at 4 degrees C, fillet quality was determined by visual assessment and by analysis of muscle firmness using a texture analyzer. Fillet quality could best be predicted by determining mean parasite numbers and spore counts in all eight tissue samples (somatic and opercular) or in four fillet samples, as the counts from opercular samples alone showed greater variability and thus decreased reliability. The variability in both plasmodia and spore numbers between tissue samples taken from an individual fish indicated that the parasites were not uniformly distributed in the somatic musculature. Therefore, to best predict the probable level of fillet degradation caused by K. thyrsites infections, multiple samples must be taken from each fish. If this is performed, a mean plasmodia count of 0.3 mm(-2) or a mean spore count of 4.0 x 10(5) g(-1) of tissue are the levels where the probability of severe myoliquefaction becomes a significant risk.

Predictors of mother-adolescent discussions about condoms: implications for providers who serve youth.

OBJECTIVE: To examine predictors of mother-adolescent communication about condoms. METHODS: Interviews were conducted with 907 mothers of adolescents aged 14 to 17 years in the Bronx, New York; Montgomery, Alabama; and San Juan, Puerto Rico, to determine whether mothers had talked with their adolescent about condoms. RESULTS: By univariate analysis, mother-adolescent communication about condoms was associated with greater knowledge about sexuality and acquired immunodeficiency syndrome, perception of having enough information to discuss condoms, information from a health-related source, less conservative attitudes about adolescent sexuality, perception that the adolescent was at risk for human immunodeficiency virus, greater ability and comfort in discussing condoms, stronger belief that condoms prevent human immunodeficiency virus/acquired immunodeficiency syndrome, and a more favorable endorsement of condoms. In multivariate analyses, mother-adolescent communication about condoms was associated with a less conservative attitude about abstinence until marriage (odds ratio [OR]: 0.73; 95% confidence interval [CI]: 0.54-0.74), greater skill in communicating about sex (OR: 1.13; 95% CI: 1.06-1.20), greater comfort in communicating about sex (OR: 1.31; 95% CI: 1.01-1.69), a more favorable endorsement of condoms (OR: 1.85; 95% CI: 1.17-2.78), and the perception that the adolescent's friends were sexually active (OR: 3.53; 95% CI: 1.97-7.16). CONCLUSION: Parents who communicate effectively about sexuality and safer sex behaviors can influence their adolescents' risk-taking behavior. Health care providers, particularly physicians, can facilitate this communication by providing to parents information about the sexual behavior of adolescents, the risks that adolescents encounter, condom use, condom effectiveness, and how to discuss condoms. They also can make referrals to programs that teach communication skills.

Posttraumatic stress disorder in rape victims: autonomic habituation to auditory stimuli.

Impaired capacity for physiological habituation may contribute to the persistence of PTSD. Habituation of autonomic responses to auditory tones was examined in 43 women in three groups: 14 adult female rape survivors with chronic PTSD, 11 without PTSD, and a comparison group of 18 who had not been raped. There were no significant differences among the groups in baseline cardiac or electrodermal activity. The PTSD group showed significantly slower electrodermal habituation, as measured by trials to extinction and percentage of nonhabituators, than did the comparison groups. The present study found slower habituation of electrodermal responses for PTSD rape victims to neutral stimuli than for non-PTSD victims and nonvictims.

Analysis of Kudoa thyrsites (Myxozoa: Myxosporea) spore antigens using monoclonal antibodies.

A method employing Percoll gradient centrifugation was developed to purify Kudoa thyrsites spores from somatic muscle tissue of Atlantic salmon Salmo salar. Highly purified spores were then used to immunize inbred BALB/c mice for derivation of hybridomas secreting Kudoa-specific monoclonal antibodies (mAbs). Analysis of mAbs by immunofluorescence microscopy and flow cytometry showed that several were specific for antigens on the surface of K. thyrsites spores whereas other mAbs reacted with polar capsules or with polar filaments of spores of K. thyrsites, K. paniformis and K. crumena. Immunoblots on spore lysates using the surface-binding mAbs showed a broad band of 46 to > 220 kDa, whereas mAbs specific for antigens of polar capsules and polar filaments detected sharper bands of various molecular masses, depending on the Kudoa species. The dominant epitope of the K. thyrsites spore surface antigen was shown to be carbohydrate as determined by its sensitivity to treatment with anhydrous trifluoromethane sulfonic acid and by its resistance to treatment with Proteinase K. Immunofluorescence microscopy using the K. thyrsites-specific mAbs on isolated, intact, permeabilized plasmodia and on thin sections of somatic muscle tissue containing plasmodia revealed intense labeling of spores both within the spore-producing plasmodia and in the flesh of infected Atlantic salmon. As few as 100 spores were detected by immunoblotting, indicating that these mAbs have potential for use in developing a field-based diagnostic test.

Reconceptualizing adolescent sexual behavior: beyond did they or didn't they?

CONTEXT: Adolescent sexual behavior is typically studied as a dichotomy: Adolescents have had sex or they have not. Broadening this view would lead to a greater understanding of teenagers' sexual behavior. METHODS: Interview data from 907 high school students in Alabama, New York and Puerto Rico were used to examine the relationships between sexual experience and a variety of social, psychological and behavioral variables. Four groups of teenagers are compared: those who did not anticipate initiating sex in the next year (delayers), those who anticipated initiating sex in the next year (anticipators), those who had had one sexual partner (singles) and those who had had two or more partners (multiples). RESULTS: Compared with delayers, anticipators reported more alcohol use and marijuana use; poorer psychological health; riskier peer behaviors; and looser ties to family school and church. Similarly, multiples reported more alcohol and marijuana use, riskier peer behaviors and looser ties to family and school than singles. Risk behaviors, peer behaviors, family variables, and school and church involvement showed a linear trend across the four categories of sexual behavior. CONCLUSIONS: The traditional sex-no sex dichotomy obscures differences among sexually inexperienced teenagers and among adolescents who have had sex. Prevention efforts must be tailored to the specific needs of teenagers with differing sexual experiences and expectations, and must address the social and psychological context in which sexual experiences occur.

Teenage partners' communication about sexual risk and condom use: the importance of parent-teenager discussions.

CONTEXT: Teenagers' communication with their partners about sex and their use of condoms may be influenced by the discussions teenagers have with their parents about sex. However, little is known about the process of parent-teenager communication on this topic. Understanding both what parents discuss with their children and how they discuss it may lead to a greater understanding of teenagers' sexual behavior. METHODS: Interviews were conducted with 372 sexually active black and Hispanic youth aged 14-17 from Alabama, New York and Puerto Rico. Regression analyses were used to examine parent-teenager discussions about sexuality and about sexual risk, and parental communication skills as predictors of teenagers' discussions about sexual risk with a partner and teenagers' condom use. RESULTS: Parent-teenager discussions about sexuality and sexual risk were associated with an increased likelihood of teenager-partner discussions about sexual risk and of teenagers' condom use, but only if parents were open, skilled and comfortable in having those discussions. Teenagers' communication with their partner about sexual risk also was associated with greater condom use, but the relationship between parent-teenager communication and teenagers' condom use was independent of this association. CONCLUSIONS: The influence on teenagers of parent-teenager discussions about sexuality and sexual risk depends on both what parents say and how they say it. Programs that foster parent-teenager communication about sexuality and sexual risk must emphasize both of these aspects.

PIP: Teenagers' communication with their partners about sex, an important factor in sexual risk reduction, has been shown to be influenced by discussions teens have with their parents about sex. The present study confirmed that parent-teen communication about sex does indeed promote teenagers' discussions with their partners about sex and condom use, but only when parents communicate in a skilled, comfortable, and open manner. Interviews were conducted during 1993-94 with 372 sexually active Black and Hispanic US high school students 14-17 years old from Alabama, New York, and Puerto Rico. On average, teens had first intercourse at age 13.7 years and had had 3.9 partners. The association between parent-teen discussions about sexuality and sexual risk and teenager-partner communication about sex was high when parental responsiveness (openness, skill, comfort) was rated high by the teenager, but this association was weaker and of only marginal significance when responsiveness was rated as low. Similarly, when parental responsiveness was high, sexuality and risk discussions were significantly associated with increased condom use during most recent intercourse and lifetime condom use. However, at low levels of parental responsiveness, sexuality discussions were negatively associated with most recent and lifetime condom use. The association between parent-teen communication and condom use was direct and independent. These findings highlight the importance of communication skills training for parents.

Patterns of condom use among adolescents: the impact of mother-adolescent communication.

OBJECTIVES: The association between the timing of discussions about condoms between mother and adolescent and adolescents' condom use during their first and subsequent sexual encounters was examined. METHODS: Sexually active adolescents reported whether and when they discussed condoms with their mother and answered questions about their own condom use. RESULTS: Mother-adolescent discussions about condoms that occurred prior to sexual debut were strongly associated with greater condom use during first intercourse and most recent intercourse, along with greater lifetime regular condom use. CONCLUSIONS: Discussions about condoms prior to sexual debut are important in promoting condom use among adolescents.

Pleasure and pain in doing well, together: an investigation of performance-related affect in close relationships.

In a series of four studies, the self-evaluation maintenance (SEM) model is used to predict peoples' self-reported affective responses to doing better or worse than their partners. Both self-protective reactions to comparison (i.e., those predicted by the original SEM model) and empathic reactions to the partner's response (i.e., those predicted by the extended SEM model) were obtained. In addition, as predicted on the basis of both models, comparisons with romantic partners resulted in a different pattern of self-reported affect than did comparisons with strangers. Unexpectedly, it appeared that empathic effects were minimal or absent among dating partners when comparisons were in areas of high self-relevance.

Parvicapsula minibicornis n. sp. (Myxozoa, Myxosporea) from the kidney of sockeye salmon (Oncorhynchus nerka) from British Columbia, Canada.

A new species of Myxosporea Parvicapsula minibicornis is described from the kidney of adult sockeye salmon (Oncorhynchus nerka) that had recently returned from the Pacific Ocean to Weaver Creek, a tributary of the Fraser River, British Columbia, Canada. Spores are ovoid, symmetrical, with 2 pyriform polar capsules at the anterior pole. The posterior pole has 2 small, pointed projections. Mean spore dimensions are length 11.0 microm, thickness (perpendicular to suture plane) 6.8 microm, and width (in sutural plane) 7.5 microm. This myxozoan is compared to other described Parvicapsula species and a Parvicapsula sp. from netpen-reared coho salmon (Oncorhynchus kisutch).

Haemobaphes disphaerocephalus, an accidental parasite of seawater pen-reared Atlantic salmon.

Gill infections by the parasitic copepod Haemobaphes disphaerocephalus (family Pennellidae) were observed on a few Atlantic salmon reared at 2 seawater netpen sites in British Columbia. This is the first report of this parasite affecting salmonids. The terminal holdfast penetrated into a branchial artery and was associated with anemia.

Kudoa miniauriculata n. sp. (Myxozoa, Myxosporea) from the musculature of bocaccio (Sebastes paucispinis) from California.

A new species of Myxosporea Kudoa miniauriculata is described from the somatic muscle of bocaccio (Sebastes paucispinis), an eastern Pacific Ocean rockfish species caught off the coast of California. Spores are stellate in apical view and suboval in side view. The tip of each valve is uplifted. Each valve has a small (0.25-0.41 micron) projection at its apical end. Mean spore dimensions were width 7.94 microns, length 5.41 microns, and polar capsule length 2.15 microns. A previous identification of K. clupeidae in bocaccio and the presence of this species on the west coast of North America is discounted.

The influence of age-related cataract on blue-on-yellow perimetry.

PURPOSE: The influence of cataract on the blue-on-yellow visual field is unknown. The aim of the study was to compare the effect of age-related cataract on the normal blue-on-yellow (B-Y), yellow-on-yellow (Y-Y) and white-on-white (W-W) visual field. METHODS: Forty normal subjects (age range, 60 to 81 years) randomly performed B-Y, Y-Y, and W-W perimetry using a modified Humphrey Field Analyser 640 (HFA) (Program 24-2). Twenty age-matched patients with cataract underwent the same testing paradigm. Cataract was classified using the LOCS II system. Ocular media absorption was measured with the HFA by determining the difference in scotopic sensitivity to 410-nm and 560-nm stimuli. Forward light scatter was measured by the direct compensation technique of van den Berg. Unweighted mean deviation (MD), short-term fluctuation, and corrected pattern standard derivation indices were calculated for each patient with cataract for each of the three stimulus combinations. RESULTS: Cataract produced an adverse effect on the MD (i.e., a more negative MD) in all patients for each of the three stimulus combinations. The magnitude depended on the degree and type of cataract and was highly correlated with forward light scatter. The attenuation in sensitivity was greatest for the B-Y and W-W stimulus combinations; the B-Y field was preferentially affected by posterior subcapsular cataract and the W-W field by anterior cortical cataract. CONCLUSIONS: Cataract predominantly causes a general reduction in B-Y sensitivity. Caution therefore needs to be exercised in the interpretation of the B-Y visual field in patients in whom glaucoma and cataract coexist.

The stability and prediction of depressive mood states in college students.

Objective criteria for predicting dysphoric mood states in college students from measures of stress and cognitive and personality variables were developed and cross-validated. Contrary to Beck's diathesis-stress model of depression, although dysfunctional attitudes, together with the number and impact of life events, self-esteem problems, and level of traditional feminine personality characteristics, predicted concurrent levels of depressive symptoms, initial level of depression was the best predictor of future depression. Cross-validation of the criteria resulted in accuracy rates of 86 to 87%. Implications of these results and some secondary findings were discussed.

Review of Myxosporea of importance in salmonid fisheries and aquaculture in British Columbia.

Several myxosporean parasites are of importance in fisheries and aquaculture in British Columbia. The PKX organism and Ceratomyxa shasta Noble, 1950 cause disease and mortality, Kudoa thyrsites (Gilchrist, 1924) and Henneguya salminicola Ward, 1919 are of importance because they infect somatic muscle, cause unsightly cysts and soft flesh, and thus reduce the market value of the fish. Myxobolus arcticus Pugachev et Khokhlov, 1979, an apparently non-pathogenic species, along with H. salminicola, is used as a biological tag in fishery management. Myxobolus arcticus has also been used in our laboratory as a model for the study of myxosporean life cycles. Other myxosporeans that have been found in salmonids in British Columbia include Myxobolus squamalis (Iverson, 1954), Myxobolus insidiosus Wyatt et Pratt, 1963, Myxidium truttae Léger, 1930, Myxidium salvelini Shulman et Konovalov, 1966, Chloromyxum sp., Parvicapsula sp., and Sphaerospora sp.

Depressive mood states and their cognitive and personality correlates in college students: they improve over time.

About 30% of 171 college student respondents reported at least mild dysphoria. Depressed mood states were associated with dysfunctional attitudes and self-esteem problems, but not with gender or self-reported problem-solving ability. Findings about sex role orientation were mixed. The freshmen reported the highest levels of dysphoria, problem-solving difficulties, and dysfunctional attitudes, but there appeared to be consistent, gradual improvements, such that by the senior year students reported significantly less dysphoria. However, a 2-month follow-up found no significant changes in these areas, which suggests that the observed improvements may occur more gradually or may be an artifact of selective attrition from college. Implications of the results and directions for future research were discussed.