Biomedical subjects

Andrew E Williams

Publications and source records attributed to Andrew E Williams.

At least 19 recordsLinked to original sources

PubMed2007

Maternally imprinted microRNAs are differentially expressed during mouse and human lung development.

MicroRNAs (miRNAs) are a recently discovered class of noncoding genes that regulate the translation of target mRNA. More than 300 miRNAs have now been discovered in humans, although the function of most is still unknown. A highly sensitive, semiquantitative real-time polymerase chain reaction method was used to reveal the differential expression of several miRNAs during the development of both mouse and human lung. Of note was the up-regulation in neonatal mouse and fetal human lung of a maternally imprinted miRNA cluster located at human chromosome 14q32.31 (mouse chromosome 12F2), which includes the miR-154 and miR-335 families and is situated within the Gtl2-Dio3 domain. Conversely, several miRNAs were up-regulated in adult compared with neonatal/fetal lung, including miR-29a and miR-29b. Differences in the spatial expression patterns of miR-154, miR-29a, and miR-26a was demonstrated using in situ hybridization of mouse neonatal and adult tissue using miRNA-specific locked nucleic acid (LNA) probes. Of interest, miR-154 appeared to be localized to the stroma of fetal but not adult lungs. The overall expression profile was similar for mouse and human tissue, suggesting evolutionary conservation of miRNA expression during lung development and demonstrating the importance of maternally imprinted miRNAs in the developmental process.

Animals↗

PubMed2006

Insulin resistance is associated with cognition among HIV-1-infected patients: the Hawaii Aging With HIV cohort.

OBJECTIVE: To determine if insulin resistance (IR) is associated with lower cognitive performance among HIV-1-infected adults and to determine if advanced age magnifies risk. DESIGN: Cross-sectional analysis within the Hawaii Aging With HIV Cohort. METHODS: We calculated the homeostasis model assessment of insulin resistance (HOMA-IR) among 145 cohort participants. Values were compared to concurrent neuropsychological test performance and cognitive diagnoses. RESULTS: Hypertension, body mass index (BMI), and non-Caucasian self-identity were directly related to insulin resistance (IR); however, age, CD4 lymphocyte count, and rates of treatment with HAART were not. In logistic regression analyses and stratifying cognition status on a 3-tiered scale (normal, minor cognitive motor disorder (MCMD), and HIV-associated dementia (HAD)), we identified an increased risk of meeting a higher diagnostic category as HOMA-IR increased (OR, 1.12; 95% CI: 1.003 to 1.242 per unit of HOMA-IR, P = 0.044). In linear regression models and among nondiabetic participants, an increasing degree of IR was associated with lower performance on neuropsychological summary scores. CONCLUSIONS: IR is associated with cognitive dysfunction in this contemporary HIV-1 cohort enriched with older individuals. Metabolic dysfunction may contribute to the multifactorial pathogenesis of cognitive impairment in the era of HAART.

AIDS Dementia Complex↗

PubMed2006

In the absence of reactive oxygen species, T cells default to a Th1 phenotype and mediate protection against pulmonary Cryptococcus neoformans infection.

In recent years, the prevalence of invasive fungal infections has increased, attributed mostly to the rising population of immunocompromised individuals. Cryptococcus neoformans has been one of the most devastating, with an estimated 6-8% of AIDS-infected patients succumbing to Cryptococcus-associated meningitis. Reactive oxygen species (ROS) are potent antimicrobial agents but also play a significant role in regulating immune cell phenotype, but cause immunopathology when produced in excess. We now show that mice lacking phagocyte NADPH oxidase have heightened macrophage and Th1 responses and improved pathogen containment within pulmonary granulomatous lesions. Consequently, dissemination of this fungus to the brain is diminished, an effect that is independent of IL-12. Similar results are described using the metalloporphyrin antioxidant manganese(III) tetrakis(N-ethyl pyridinium-2-yl)porphyrin, which also promoted a protective Th1 response and reduced dissemination to the brain. These findings are in sharp contrast to the protective potential of ROS against other fungal pathogens, and highlight the pivotal role that ROS can fulfill in shaping the profile of the host's immune response.

Animals↗

PubMed2006

Lowest ever CD4 lymphocyte count (CD4 nadir) as a predictor of current cognitive and neurological status in human immunodeficiency virus type 1 infection--The Hawaii Aging with HIV Cohort.

Low CD4 lymphocyte count was a marker for neurological disease in human immunodeficiency virus type 1 (HIV-1); but is now less common among patients with access to highly active antiretroviral therapy. In this study, the authors determine the reliability of self-reported CD4 nadir and its predictive value for neurological status. The authors identify a high degree of reliability (r = .90). After adjusting for age, current CD4 count, and duration of HIV-1, CD4 nadir relates to a current diagnosis of HIV-associated dimentia (HAD) (odds ratio [OR]: 1.395 (1.106-1.761), P = .005) and distal symmetric polyneuropathy (DSPN) (OR: 1.479 (1.221-1.769, P < .001).

Acquired Immunodeficiency Syndrome↗

PubMed2005

Colonic bacterial infection abrogates eosinophilic pulmonary disease.

Induction of immunity to one pathogen in the lungs modifies the microenvironment and alters immunopathological changes that result from a second, unrelated pulmonary infection. However, it is unclear whether immunity generated at distant sites also affects lung immune responses. Here, we show that infection with the gut-restricted bacterium Citrobacter rodentium modifies immunopathological changes that result from pulmonary Cryptococcus neoformans infection. Th2 cytokine-driven pulmonary eosinophilia induced by C. neoformans infection was reduced, and the enhanced Th1 cytokine environment afforded more-rapid clearance of the fungus in C. rodentium-immune mice. The activated and intraepithelial (CD103+) T cell populations that expand after C. neoformans infection were diminished in C. rodentium-immune mice. T cell cross-reactivity was absent, but cross-reactive antibodies were detected. It is of importance to the "hygiene hypothesis" that these data indicate that an immune response induced by a gut-restricted pathogen can modify the immune outcome after pulmonary infection, suggesting that cell-phenotype modifications occur across mucosal sites.

Animals↗

PubMed2005

HIV-associated wasting in the era of highly active antiretroviral therapy: a syndrome of residual HIV infection in monocytes and macrophages?

Human immunodeficiency virus (HIV) infection in peripheral blood mononuclear cells (PBMCs) might be influencing the development of wasting in the era of potent antiretroviral therapy. In a retrospective study of 57 subjects, HIV proviral DNA levels in PBMCs were higher in subjects whose body weight decreased by >5% one year after initiation of highly active antiretroviral therapy, compared with subjects whose body weight was stable or increased (median HIV proviral DNA load, 8.9 vs. 0.9 copies/10(6) PBMCs; P = .006).

Adult↗

PubMed2005

Diabetes, insulin resistance, and dementia among HIV-1-infected patients.

OBJECTIVES: Metabolic complications have been associated with HIV-1 infection and with long-term use of antiretroviral (ARV) medications. In some studies, such complications have been linked to cardiovascular events, yet limited data exist concerning metabolic complications and dementia. The objective of this study was to examine the relationship between HIV-associated dementia (HAD) and diabetes among patients with HIV-1 infection. DESIGN: Cross-sectional analysis of entry data for a longitudinal cohort study. METHODS: A total of 203 participants who were enrolled in the Hawaii Aging with HIV Cohort between October 2001 and November 2003 served as the study population. Research case definitions of HAD were determined in consensus conferences by a panel that included neurologists, neuropsychologists, and a geriatrician. Diabetes was determined by self-report or a fasting glucose level > 125 mg/dL. RESULTS: Participants' ages ranged between 20-76 years at enrollment with approximately one-half aged >/=50 years. After adjustment for important covariates including age, education, ethnicity, CD4 lymphocyte count, duration of HIV infection, and protease inhibitor-based ARV therapy, we found a statistically significant association of diabetes with HAD (odds ratio 5.43, 1.66-17.70). A significant association remained after adjustment for other vascular risk factors. Among participants without diabetes, fasting glucose levels were higher with increasing impairment category. CONCLUSIONS: Within the Hawaii Aging with HIV Cohort, a longitudinal study enriched with older HIV-1-infected individuals, diabetes is associated with prevalent dementia. This finding is not fully explained by age or coexisting vascular risk factors. Evaluation of underlying mechanisms is warranted.

AIDS Dementia Complex↗

PubMed2005

Stimulation via Toll-like receptor 9 reduces Cryptococcus neoformans-induced pulmonary inflammation in an IL-12-dependent manner.

Cytosine-phosphate-guanosine-containing oligodeoxynucleotides (CpG ODN) are important vaccine adjuvants that promote Th1-type immune responses. Cryptococcus neoformans is a serious human pathogen that replicates in the lung but may disseminate systemically leading to meningitis, particularly in immunocompromised individuals. Immunization of susceptible C57BL/6 mice with CpG ODN deviates the immune response from a Th2- toward a Th1-type response following infection with C. neoformans. CpG also induces IL-12, TNF, MCP-1 and macrophage nitric oxide production. CD4(+) and CD8(+) T cells producing IFN-gamma increase in frequency, while those producing IL-5 decrease. More importantly, pulmonary eosinophilia is significantly reduced, an effect that depends on IL-12 and CD8(+) T cells but not NK cells. CpG treatment also reduces the burden of C. neoformans in the lung, an effect that is IL-12-, NK cell- and T cell-independent and probably reflects a direct effect of CpG on pathogen opsonization or an enhancement of macrophage antimicrobial activity. An equivalent beneficial effect is also observed when CpG ODN treatment is delivered during established cryptococcal disease. This is the first study documenting that promotion of lung TLR9 signaling using synthetic agonists enhances host defense. Activation of innate immunity has clear therapeutic potential and may even be beneficial in patients with acquired immune deficiency.

Adjuvants, Immunologic↗

PubMed2005

The human fear-circuitry and fear-induced fainting in healthy individuals--the paleolithic-threat hypothesis.

The Paleolithic-Threat hypothesis reviewed here posits that habitual efferent fainting can be traced back to fear-induced allelic polymorphisms that were selected into some genomes of anatomically, mitochondrially, and neurally modern humans (Homo sapiens sapiens) in the Mid-Paleolithic because of the survival advantage they conferred during periods of inescapable threat. We posit that during Mid-Paleolithic warfare an encounter with "a stranger holding a sharp object" was consistently associated with threat to life. A heritable hardwired or firm-wired (prepotentiated) predisposition to abruptly increase vagal tone and collapse flaccidly rather than freeze or attempt to flee or fight in response to an approaching sharp object, a minor injury, or the sight of blood, may have evolved as an alternative stress-induced fear-circuitry response. Such a stable (balanced) polymorphism for the hemodynamically "paradoxical" flaccid-immobility in response to these stimuli may have increased some non-combatants' chances of survival. This is consistent with the unusual age and sex pattern of fear-induced fainting. The Paleolithic-Threat hypothesis also predicts a link to various hypo-androgenic states (e. g. low dehydroxy-epiandrosterone-sulfate. We offer five predictions testable via epidemiological, clinical, and ethological/ primatological methods. The Paleolithic-Threat hypothesis has implications for research in the aftermath of man-made disasters, such as terrorism against civilians, a traumatic event in which this hypothesis predicts epidemics of fear-induced fainting.

Adult↗

PubMed2005

The clenching-grinding spectrum and fear circuitry disorders: clinical insights from the neuroscience/paleoanthropology interface.

This review discusses the clenching-grinding spectrum from the neuropsychiatric/neuroevolutionary perspective. In neuropsychiatry, signs of jaw clenching may be a useful objective marker for detecting or substantiating a self-report of current subjective emotional distress. Similarly, accelerated tooth wear may be an objective clinical sign for detecting, or substantiating, long-lasting anxiety. Clenching-grinding behaviors affect at least 8 percent of the population. We argue that during the early paleolithic environment of evolutionary adaptedness, jaw clenching was an adaptive trait because it rapidly strengthened the masseter and temporalis muscles, enabling a stronger, deeper and therefore more lethal bite in expectation of conflict (warfare) with conspecifics. Similarly, sharper incisors produced by teeth grinding may have served as weaponry during early human combat. We posit that alleles predisposing to fear-induced clenching-grinding were evolutionarily conserved in the human clade (lineage) since they remained adaptive for anatomically and mitochondrially modern humans (Homo sapiens) well into the mid-paleolithic. Clenching-grinding, sleep bruxism, myofacial pain, craniomaxillofacial musculoskeletal pain, temporomandibular disorders, oro-facial pain, and the fibromyalgia/chronic fatigue spectrum disorders are linked. A 2003 Cochrane meta-analysis concluded that dental procedures for the above spectrum disorders are not evidence based. There is a need for early detection of clenching-grinding in anxiety disorder clinics and for research into science-based interventions. Finally, research needs to examine the possible utility of incorporating physical signs into Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition posttraumatic stress disorder diagnostic criteria. One of the diagnostic criterion that may need to undergo a revision in Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition is Criterion D (persistent fear-circuitry activation not present before the trauma). Grinding-induced incisor wear, and clenching-induced palpable masseter tenderness may be examples of such objective physical signs of persistent fear-circuitry activation (posttraumatic stress disorder Criterion D).

Anthropology↗

PubMed2004

An investigation of mammographic density and gene variants in healthy women.

This cross-sectional study examined if polymorphisms in genes that code for enzymes involved in the production and metabolism of estrogens are associated with mammographic density, a strong predictor of breast cancer risk. The study included 328 healthy women of different ethnicities who underwent mammographic screening and donated a blood or mouthwash sample for DNA analysis. After digitizing cranio-caudal views of the mammograms, we performed computer-assisted mammographic density assessment. Following DNA extraction, samples were analyzed for polymorphisms in the COMT (Val158Met), CYP1A1 (Ile462Val), CYP1B1 (Val432Leu), CYP1A2 (*1F) and CYP17 (T27C) genes using PCR-RFLP. Breast density was lower in Caucasians than in Asians. Caucasian women were less likely to carry the CYP1A1 variant allele and more likely to carry the variant alleles for CYP1B1 and COMT than women with Asian or Hawaiian ancestry. The low-activity COMT and CYP1A2 variant alleles were weakly related to lower percent mammographic density after adjustment for age, ethnicity, body mass index and reproductive variables (p for gene-dosage =0.08 and 0.05, respectively). These relations were observed in premenopausal women only and were similar in direction and magnitude after stratification by ethnicity. We found no significant associations between breast density and the variant alleles for CYP1A1, CYP1B1 and CYP17. Our data suggest lower mammographic density for women carrying the COMT and CYP1A2 variant alleles than for women carrying the common alleles, though this is the opposite of what is commonly hypothesized from the enzyme function.

Adult↗

PubMed2004

The STRS (shortness of breath, tremulousness, racing heart, and sweating): A brief checklist for acute distress with panic-like autonomic indicators; development and factor structure.

BACKGROUND: Peritraumatic response, as currently assessed by Posttraumatic Stress Disorder (PTSD) diagnostic criterion A2, has weak positive predictive value (PPV) with respect to PTSD diagnosis. Research suggests that indicators of peritraumatic autonomic activation may supplement the PPV of PTSD criterion A2. We describe the development and factor structure of the STRS (Shortness of Breath, Tremulousness, Racing Heart, and Sweating), a one page, two-minute checklist with a five-point Likert-type response format based on a previously unpublished scale. It is the first validated self-report measure of peritraumatic activation of the autonomic nervous system. METHODS: We selected items from the Potential Stressful Events Interview (PSEI) to represent two latent variables: 1) PTSD diagnostic criterion A, and 2) acute autonomic activation. Participants (a convenience sample of 162 non-treatment seeking young adults) rated the most distressing incident of their lives on these items. We examined the factor structure of the STRS in this sample using factor and cluster analysis. RESULTS: Results confirmed a two-factor model. The factors together accounted for 68% of the variance. The variance in each item accounted for by the two factors together ranged from 41% to 74%. The item loadings on the two factors mapped precisely onto the two proposed latent variables. CONCLUSION: The factor structure of the STRS is robust and interpretable. Autonomic activation signs tapped by the STRS constitute a dimension of the acute autonomic activation in response to stress that is distinct from the current PTSD criterion A2. Since the PTSD diagnostic criteria are likely to change in the DSM-V, further research is warranted to determine whether signs of peritraumatic autonomic activation such as those measured by this two-minute scale add to the positive predictive power of the current PTSD criterion A2. Additionally, future research is warranted to explore whether the four automatic activation items of the STRS can be useful as the basis for a possible PTSD criterion A3 in the DSM-V.

Journal Article↗

PubMed2004

Co-stimulation: novel methods for preventing viral-induced lung inflammation.

Respiratory infections cause significant morbidity and mortality worldwide. Although an immune response is required to eliminate respiratory pathogens, if unchecked, it can damage surrounding tissues and block primary lung function. Based on our knowledge of immune T-cell activation, there are several pathways to which immune intervention could be applied. However, relatively few interventions target only those immune cells that are responding to antigens. OX40 and 4-1BB are members of the tumour necrosis factor receptor family and are expressed on the surface of T cells in several inflammatory conditions. Recently, the inhibition of OX40 has proved beneficial during influenza virus infection. This review highlights the recent advances in the manipulation of such molecules and how they have been applied to inflammatory conditions that are caused by viruses in the lung.

CD40 Antigens↗

PubMed2004

A 2-year soy intervention in premenopausal women does not change mammographic densities.

Soy consumption may be related to lower breast cancer risk as assessed by breast density. The aims of this 2-y trial were to examine the effects of soy foods and lifetime soy intake on mammographic density. After 220 premenopausal women were randomly assigned to the intervention or control group, the former group consumed 2 daily servings of soy foods equivalent to 50 mg of isoflavones and the latter consumed their regular diet. The respective dropout rates were 15.6 and 12.6%; adherence to the study regimen was high. We assessed lifetime soy intake with a questionnaire and measured breast density in screening mammograms obtained at baseline and at the end of the trial for 98 intervention and 103 control women using a computer-assisted method. None of the mammographic outcomes differed significantly by experimental group. The total area of the breast increased and the size of the dense areas decreased significantly over time in both groups. After 2 y, the mean percentage density had decreased by 2.8 and 4.1% in intervention and control women, respectively. Women who reported eating more soy during their lives had higher percentage densities than women whose diet included little soy; this difference was significant only in Caucasians. Lower soy intake during early life and higher soy intake during adulthood predicted a greater reduction in the percentage density during the study period. After 2 y of intervention, we observed no significant differences in mammographic densities by intervention status, but it appears that soy consumption throughout life may have some effect on breast density.

Adult↗

PubMed2004

Effects of a 2-year randomized soy intervention on sex hormone levels in premenopausal women.

OBJECTIVE: Several epidemiologic studies have described protective effects of soy consumption against breast cancer. The goal of this trial among premenopausal women was to examine the effect of soy foods on menstrual cycle length and circulating sex hormone levels. METHODS: This 2-year dietary intervention randomized 220 healthy premenopausal women. The intervention group consumed two daily servings of soy foods containing approximately 50 mg of isoflavones; the control group maintained their regular diet. Five blood samples (obtained in months 0, 3, 6, 12, and 24) were taken 5 days after ovulation as determined by an ovulation kit. The serum samples were analyzed for estrone, estradiol, sex hormone binding globulin, androstenedione, and progesterone by immunoassay. RESULTS: At baseline, both groups had similar demographic, anthropometric, and nutritional characteristics. The dropout rates of 15.6% (17 of 109) in the intervention group and 12.6% (14 of 111) in the control group did not differ significantly. According to soy intake logs, 24-hour recalls, and urinary isoflavone excretion, the women closely adhered to the study regimen. Menstrual cycles became slightly shorter in both groups but did not differ by group. Mixed general linear models indicated no significant intervention effect on any of the serum hormones. However, androstenedione and progesterone decreased significantly over time in both groups. CONCLUSIONS: The results of this study suggest that the preventive effects of soy on breast cancer risk in premenopausal women may not be mediated by circulating sex hormone levels. Different mechanisms of actions or effects of exposure earlier in life are alternate hypotheses that require further investigation.

Adult↗

PubMed2003

A cross-sectional investigation of breast density and insulin-like growth factor I.

Our study investigated the association of breast cancer risk as assessed by mammographic density with insulin-like growth factor I (IGF-I) and one of its binding proteins (IGFBP-3) in healthy premenopausal women with different ethnic backgrounds. In a cross-sectional design, we analyzed the baseline mammograms and fasting serum samples (collected 5 days after ovulation) of premenopausal women entering a nutritional intervention. Serum concentrations of IGF-I and IGFBP-3 were measured by double-antibody ELISA. Mammographic densities were assessed using a computer-assisted method. We calculated Spearman correlation coefficients between mammographic characteristics and analytes and estimated means of mammographic characteristics by quartiles of IGF-I and IGFBP-3 while adjusting for age, body mass index (BMI) and reproductive factors. In this group of 240 women, IGF-I, IGFBP-3 and percent densities did not differ significantly by ethnicity. Whereas mammographic densities were not associated with IGF-I, we found an inverse relation with IGFBP-3 (r(s) = -0.15, p = 0.02) and a positive association with the IGF-I/IGFBP-3 ratio (r(s) = 0.13, p = 0.04). The size of the dense areas was not associated with the analytes, but the size of the nondense areas was correlated directly with IGFBP-3 (r(s) = 0.20, p = 0.002) and inversely with the molar ratio (r(s) = -0.19, p = 0.004). These associations were limited to women with a BMI of less than 25 kg/m(2). These results suggest that the balance of circulating IGF-I and IGFBP-3 levels may influence the growth of the fatty part of the breast more than the epithelial and stromal breast tissue, but the exact mechanism of action needs to be explored in more detail.

Adult↗

PubMed2003

Validation of a soy questionnaire with repeated dietary recalls and urinary isoflavone assessments over one year.

This study assessed the validity and reliability of a 12-item soy questionnaire designed for use in cancer prevention research. The questionnaire measures soy intake over the past year. Subjects were 199 healthy 35- to 46-yr-old premenopausal women participating in an ongoing soy intervention study. Soy questionnaire estimates of isoflavone intake over 1 yr were compared with individual and combined estimates from two reference measures covering the same period: three or four repeated 24-h recalls and one or two repeated urine analyses. The sensitivity and specificity of the soy questionnaire in classifying high vs. low exposure (high exposure = soy intervention group membership) were comparable with 24-h recalls and were superior to urine analyses (sensitivity = 94.8%, 97.9%, and 71.1%; specificity = 95.1%, 97.1%, and 90.3% for the soy questionnaire, 24-h recalls, and urine analyses, respectively). Soy questionnaire isoflavone estimates were highly correlated with the combination of the two reference measures for the entire study population. Its brevity, ease of administration, and good measurement properties over a 1-yr period make the soy questionnaire well suited to the needs of researchers who wish to identify high and low consumers of soy foods, especially in populations who consume traditional Asian soy foods.

Adult↗

PubMed2002

The temporal reliability of serum estrogens, progesterone, gonadotropins, SHBG and urinary estrogen and progesterone metabolites in premenopausal women.

BACKGROUND: There is little existing research to guide researchers in estimating the minimum number of measurement occasions required to obtain reliable estimates of serum estrogens, progesterone, gonadotropins, sex hormone-binding globulin (SHBG), and urinary estrogen and progesterone metabolites in premenopausal women. METHODS: Using data from a longitudinal study of 34 women with a mean age of 42.3 years (SD = 2.6), we calculated the minimum number of measurement occasions required to obtain reliable estimates of 12 analytes (8 in blood, 4 in urine). Five samples were obtained over 1 year: at baseline, and after 1, 3, 6, and 12 months. We also calculated the percent of true variance accounted for by a single measurement and intraclass correlation coefficients (ICC) between measurement occasions. RESULTS: Only 2 of the 12 analytes we examined, SHBG and estrone sulfate (E1S), could be adequately estimated by a single measurement using a minimum reliability standard of having the potential to account for 64% of true variance. Other analytes required from 2 to 12 occasions to account for 81% of the true variance, and 2 to 5 occasions to account for 64% of true variance. ICCs ranged from 0.33 for estradiol (E2) to 0.88 for SHBG. Percent of true variance accounted for by single measurements ranged from 29% for luteinizing hormone (LH) to 92% for SHBG. CONCLUSIONS: Experimental designs that take the natural variability of these analytes into account by obtaining measurements on a sufficient number of occasions will be rewarded with increased power and accuracy.

Journal Article↗