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Biomedical subjects

K S Miller

Publications and source records attributed to K S Miller.

At least 19 recordsLinked to original sources
PubMed2001

Adolescent sexual risk behavior: a multi-system perspective.

Adolescents are at high risk for a number of negative health consequences associated with early and unsafe sexual activity, including infection with human immunodeficiency virus, other sexually transmitted diseases, and unintended pregnancy. As a result, researchers have attempted to identify those factors that influence adolescent sexual risk behavior so that meaningful prevention and intervention programs may be developed. We propose that research efforts so far have been hampered by the adoption of models and perspectives that are narrow and do not adequately capture the complexity associated with the adolescent sexual experience. In this article, we review the recent literature (i.e., 1990-1999) pertaining to the correlates of adolescent sexual risk-taking, and organize the findings into a multisystemic perspective. Factors from the self, family, and extrafamilial systems of influence are discussed. We also consider several methodological problems that limit the literature's current scope, and consider implications of the adoption of a multisystemic framework for future research endeavors. We conclude with a discussion of the implications of the available research for practitioners working to reduce sexual risk behavior among adolescents.

Adolescent↗
PubMed2001

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.

Adolescent↗
PubMed2000

HIV/AIDS among African Americans: progress or progression?

OBJECTIVES: To review data on the extent of HIV infection and associated risk behaviors, the occurrence of AIDS, and HIV-related mortality in African Americans and to suggest what can be done to reduce HIV exposure and infection in this population. DESIGN/METHODS: Review of epidemiologic, published, multisite data on HIV infection in, and related behaviors of, African Americans. RESULTS: On every epidemiologic measure in common use, African Americans, compared with the four other federally recognized racial/ethnic groups, have the most severe epidemic. The trend data show continuing growth in the African American epidemic despite the availability of effective behavioral interventions and biomedical treatments. Few published intervention studies with African American populations have been adequately evaluated; nor have they focused proportionately on men who have sex with men, a group in the African American community with continuing high rates of infection. CONCLUSIONS: Rates of HIV transmission and disease among African Americans are high, disproportionate, and are not declining as significantly in response to effective interventions as they are among whites. Attention is urgently needed to increase our understanding of risk behaviors, social networks, and specific factors in the African American community that can be altered to reduce HIV infection. Macroenvironmental factors--poverty, social class, racism--need to be studied to suggest possible intervention components to reduce rates of HIV transmission and to increase the use of therapies that are more effectively slowing disease progression and lowering death rates among whites.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Evaluation of a fluorescent lectin-based staining technique for some acidophilic mining bacteria.

A fluorescence-labeled wheat germ agglutinin staining technique (R. K. Sizemore et al., Appl. Environ. Microbiol. 56:2245-2247, 1990) was modified and found to be effective for staining gram-positive, acidophilic mining bacteria. Bacteria identified by others as being gram positive through 16S rRNA sequence analyses, yet clustering near the divergence of that group, stained weakly. Gram-negative bacteria did not stain. Background staining of environmental samples was negligible, and pyrite and soil particles in the samples did not interfere with the staining procedure.

Acetobacteraceae↗
PubMed2000

Adolescent sexual behavior in two ethnic minority groups: a multisystem perspective.

Adolescents are at high risk for a number of negative health consequences associated with early and unsafe sexual activity, such as infection with HIV and other sexually transmitted diseases, as well as unintended pregnancy. In the present study, a multisystem model was applied to one adolescent sexual behavior, penile-vaginal intercourse. Nine hundred seven Black and Hispanic adolescents (aged 14 to 17 years) and their mothers were interviewed. Factors from three systems (self, family, and extrafamilial) that are influential in the lives of adolescents were evaluated using four outcome measures. Factors from most or all systems emerged as predictors of each outcome measure. A cumulative risk index suggested a linear relationship between the number of systems identified as being at risk and indicators of adolescent sexual behavior. The implications for prevention are discussed.

Adolescent↗
PubMed1999

Cell surface sialic acid and the regulation of immune cell interactions: the neuraminidase effect reconsidered.

It has been known for over a decade that sialidase (neuraminidase) treatment could substantially enhance the capacity of resting B cells to stimulate the proliferation of allogeneic and antigen specific, syngeneic T cells. Thus, cell-surface sialic acid was implicated as a potential modulator of immune cell interaction. However, little progress has been made in either identifying explicit roles for sialic acid in this system or in hypothesizing mechanisms to explain the "neuraminidase effect." Here we show for the first time that cell surface sialic acid on medium incubated B cells blocks access to costimulatory molecules on the B cell surface, and that this is the most likely explanation for the neuraminidase effect. Further, we show that it is likely to be upregulation of ICAM-1 and its subsequent engagement of LFA-1 rather than loss of cell surface sialic acid that in part regulates access to CD86 and other costimulatory molecules. However, we cannot exclude a role for CD86-bound sialic acid on the B cell in modulating binding to T cell CD28. Because sialidase treatment of resting B cells but not resting T cells enables T cell activation, we suggest that sialidase treatment may still be an analogue for an authentic step in B cell activation, and show that for highly activated B cells (activated with polyclonal anti-IgM plus INF-gamma) there is specific loss 2, 6-linked sialic acid. Potential roles for sialic acid in modulating B cell/T cell collaboration are discussed.

Animals↗
PubMed1999

Survival of Anisakis simplex in microwave-processed arrowtooth flounder (Atheresthes stomias).

The purpose of this study was to define the relationship between survival and temperature of nematodes of the species Anisakis simplex in microwave-processed arrowtooth flounder (Atheresthes stomias). Ten fillets (each 126 to 467 g, 0.5 to 1.75 cm thick), with an average of five larvae of Anisakis simplex per fillet, were processed to target temperatures on high (100%) power using a commercial 700-W microwave oven. Fillets were neither covered nor rotated and had a temperature probe inserted to two-thirds depth into the thickest portion. After the fillet was digested using a 1% pepsin solution, the viability of nematodes was determined by viewing them under a dissecting microscope. Survival rates were 31% at 140 degrees F (60 degrees C), 11% at 150 degrees F (65 degrees C), 2% at 160 degrees F (71 degrees C), 3% at 165 degrees F (74 degrees C), and 0% at 170 degrees F (77 degrees C). Microwave processing of standardized fillet "sandwiches," 14 cm long, 4.5 cm wide, and approximately 1.75 cm high, each of which was preinoculated with 10 live nematodes, resulted in no survival at either 160 degrees F or 170 degrees F. Using ultraviolet light to detect both viable and nonviable nematodes in fillet sandwiches as an alternative method to pepsin digestion resulted in survival rates of 1% at 140 degrees F (60 degrees C), 3% at 145 degrees F (63 degrees C), and 0% at 150 degrees F (65 degrees C). Smaller fillet sandwiches, which most likely had fewer cold spots during microwave processing, required 150 degrees F (65 degrees C), whereas larger whole fillets required 170 degrees F (77 degrees C) to kill larvae of Anisakis simplex. The parasites were most likely inactivated by a thermal mechanism of microwave treatment. Damage to the nematodes was often evident from ruptured cuticles that were no longer resistant to digestive enzymes. The high hydrostatic pressure and low chloride content of the pseudocoelomic fluid probably contributed greatly to the damage incurred by the larvae.

Animals↗
PubMed1999

Sexually transmitted diseases, unintended pregnancy, and adolescent health promotion.

Adolescence is a critical period in the development of sexual behaviors that may lead to acquiring sexually transmitted diseases (STDs), including human immunodeficiency virus (HIV), and to unintended pregnancy. Understanding adolescent sexual behavior is essential for understanding adolescents' risk of pregnancy and STD/HIV infection and for planning and evaluating health promotion activities. This chapter reviews the sexual behaviors and psychosocial factors associated with STDs and unintended pregnancy among adolescents as well as school-, community-, and clinic-based interventions designed to reduce risk behaviors and promote adolescent sexual health.

Adolescent↗
PubMed1998

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.

Adolescent↗
PubMed1997

Reports of severe physical punishment and exposure to animal cruelty by inmates convicted of felonies and by university students.

A self-report questionnaire designed to assess abusive childhood environments and exposure to animal cruelty was administered to 314 inmates in a prisoner classification center. Although high rates of physical punishment characterized the entire sample, persons charged with violent, but nonhomicidal crimes reported more severely punitive childhood histories than those charged with homicidal crimes, sex offenses, and nonviolent offenses. Some exposure to animal cruelty was widespread in the sample, but there was no association between experiencing animal cruelty and the type of crime committed. Moreover, there were only modest associations between animal cruelty experiences and the aversive childhood histories of the subjects, as well as the subjects' reported use of physical and sexual coercion in dating and intimate relationships. To determine whether the high base rate of exposure to animal cruelty was unique to the incarcerated sample, a follow-up study was completed with university undergraduates. Widespread exposure to some animal cruelty was reported by undergraduates; there were modest associations between reporting animal cruelty and reporting punitive and acrimonious childhood histories. In general, the findings were consistent with the hypothesis that there is an association between punitive childhood histories and antisocial behavior but not consistent with the hypothesis that exposure to animal cruelty is importantly related to antisocial behavior or child maltreatment.

Adolescent↗
PubMed1997

Adolescent heterosexual experience: a new typology.

PURPOSE: The purpose of this paper is to define a typology that encompasses the full range of adolescent heterosexual behavior; to compare the usefulness of the new typology with that of the traditional dichotomy of "sexually active"/"sexually inactive" for understanding sexual behavior among adolescents; and to determine the implications of the new typology for the design and implementation of HIV prevention programs targeting adolescents. METHODS: Detailed face-to-face interviews were conducted with a cross-sectional sample of 907 mothers and their adolescents, ages 14-17 years, recruited from public high schools in Alabama, New York, and Puerto Rico. Information from the adolescent survey on precoital sexual behaviors and STD/HIV sexual risk and risk reduction behaviors was examined. A typology of adolescent heterosexual experiences was constructed using four behavioral dimensions. RESULTS: Ninety-nine percent (n = 894) of the sample was classified into one of the five patterns of sexual experience: Delayers, Anticipators, One-timers, Steadies, and Multiples. Among the participants who were not sexually active, precoital behaviors differed significantly between the 22% who anticipated initiating sexual intercourse in the next year (Anticipators) and those who did not (Delayers). Among those traditionally classified as "sexually active", One-timers and Steadies were significantly older when they first had penile-vaginal intercourse than those who had multiple partners. One-timers were more likely to use condoms than Steadies or Multiples, and only Multiples reported previous STDs. CONCLUSION: A typology that defines a range of adolescent heterosexual experiences was developed, and it was possible to classify 99% of our sample. The traditional dichotomy between "sexually active" vs. "not active" hides important behavioral intentions and sexual practices. These differences must be taken into account in the development and implementation of HIV prevention programs that target adolescents.

Adolescent↗
PubMed1997

Role of parenting in adolescent deviant behavior: replication across and within two ethnic groups.

The role of 2 parenting variables, monitoring and communication, in adolescent deviant behavior was examined within 4 samples; Black Americans living in Montgomery, Alabama, and the Bronx, New York, and Hispanics living in the Bronx, New York, and San Juan, Puerto Rico. The participants comprised 907 14- to 16-year-old adolescents and their mothers recruited through high schools in 3 communities. The results indicated that higher levels of parental monitoring, but not parent--adolescent communication, predicted lower levels of adolescent deviance in each of the samples. The replication of these findings in samples that vary by ethnicity and location provides strong support for the generalizability of the association between parental monitoring and low levels of adolescent deviant behavior.

Adolescent↗
PubMed1996

Glycosylation of native MHC class Ia molecules is required for recognition by allogeneic cytotoxic T lymphocytes.

The question whether or not target cell N-linked carbohydrate participates in cytotoxic T lymphocyte (CTL) mediated cytolysis has been in contention for well over a decade. Much of the evidence supporting a role for N-linked carbohydrate stems from the treatment of target cells with the glycosylation inhibitor tunicamycin (TM). In this report, we show that treatment of targets with TM, but not other inhibitors of complex carbohydrate formation (swainsonine, 1-deoxynojirimycin, and 1-deoxymannojirimycin), abrogates the lytic response. We conclude that N-linked complex carbohydrates are not absolutely required for the maturation or function of any target cell glycoconjugate directly involved in the lytic process. However, we show that TM treatment of target cells leads to the loss of an MHC class Ia epitope known to be required for T cell triggering. Further, we show that only target cells expressing class Ia molecules with functional glycosylation sequons are subject to the TM effect. From these results we conclude that while N-linked glycosylation of native MHC class Ia molecules is required for antigen presentation, the exact structural motif of the glycan is not important.

1-Deoxynojirimycin↗
PubMed1996

Prevalence of abnormal Pap smears in rural family practice.

The purpose of this study was to examine the prevalence of abnormal Pap smears in rural family practice, to compare this to the published literature, and to determine if the prevalence of abnormalities is higher in the younger age group (<=35 years of age). A retrospective chart audit was performed on all Pap smears from four rural family practice sites during a 12-month period. Data collected were Pap smear result, patient's age, and interval since previous Pap smear. Statistical analysis was used to determine if the prevalence of abnormal Pap smears was consistent among the practices as well as similar to the three larger published studies. Also, chi-square analysis was used to compare the prevalence of abnormal Pap smears in the younger (<=35 years of age) versus the older (>35 years of age) age groups. There were 2,891 Pap smears reviewed, with 782 (27%) recorded as abnormal. The prevalence of cervical intraepithelial neoplasia (CIN) (76 or 2.6%) was compared to the published literature and was found to be statistically significantly higher (chi square=772.194, P=0.000). The prevalence of abnormal Pap smears was higher in the younger than age 35 group when compared to the older than age 35 age group (chi square=20.953, P=0.000). Pap smear interval and age varied between the four practice sites, but the prevalence of CIN was not statistically different (chi square=3.154, P=0.368). The results of this study suggest that rural family physicians may encounter abnormal Pap smears at rates similar to those reported in the literature. This study also suggests that the prevalence of abnormal Pap smears may be higher in the younger groups in this population.

Adult↗
PubMed1996

Quantifying cell mono-layer cultures by video imaging.

A method is described in which the relative number of adherent cells in multi-well tissue-culture plates is assayed by staining the cells with Giemsa and capturing the image of the stained cells with a video camera and charged-coupled device. The resultant image is quantified using the associated video imaging software. The method is shown to be sensitive and reproducible and should be useful for studies where quantifying relative cell numbers and/or proliferation in vitro is required.

Animals↗