Transfer of maternal colostral leukocytes promotes development of the neonatal immune system I. Effects on monocyte lineage cells

Although it has been established that maternal leukocytes traffic from colostrum into the neonatal circulation, the effects of these cells on neonatal immunity are only beginning to be understood. This study examined the effects of maternal colostral leukocytes on development and maturation of neonatal antigen presenting cells. At birth, groups of neonatal calves received whole or cell-free colostrum (CFC) from their respective dams. Peripheral blood samples were obtained over the first 4 weeks of life, and expression of surface markers associated with cellular activation and physiological stress were monitored on monocyte lineage cells. Calves receiving cell-free colostrum at birth expressed elevated levels of CD11a, CD11c, and CD14, compared to calves receiving whole colostrum (C). Calves receiving cell-free colostrum had an elevated number of monocytes in the peripheral blood during the first 2 weeks of life, however, these cells expressed lower levels of expression of CD25 and MHC class I compared to calves receiving whole colostrum. The most significant differences in marker expression occurred within the first 7 days of life.

Children's estimates of food portion size: the development and evaluation of three portion size assessment tools for use with children

A number of methods have been developed to assist subjects in providing an estimate of portion size but their application in improving portion size estimation by children has not been investigated systematically. The aim was to develop portion size assessment tools for use with children and to assess the accuracy of children's estimates of portion size using the tools. The tools were food photographs, food models and an interactive portion size assessment system (IPSAS). Children (n 201), aged 4–16 years, were supplied with known quantities of food to eat, in school. Food leftovers were weighed. Children estimated the amount of each food using each tool, 24 h after consuming the food. The age-specific portion sizes represented were based on portion sizes consumed by children in a national survey. Significant differences were found between the accuracy of estimates using the three tools. Children of all ages performed well using the IPSAS and food photographs. The accuracy and precision of estimates made using the food models were poor. For all tools, estimates of the amount of food served were more accurate than estimates of the amount consumed. Issues relating to reporting of foods left over which impact on estimates of the amounts of foods actually consumed require further study. The IPSAS has shown potential for assessment of dietary intake with children. Before practical application in assessment of dietary intake of children the tool would need to be expanded to cover a wider range of foods and to be validated in a ‘real-life’ situation.

Associations between youth assets and sexual activity: does adult supervision play a role?

BACKGROUND

Youth participation in sexual risk behaviours continues to be a critically important public health topic. Additionally, as youth are frequently being left alone during the day without adult supervision, there are increased opportunities for sexual risk-taking behaviour. This study examined how the relationships of nine youth assets and sexual activity may vary according to the stratification of youth into two groups: self-care and supervised.

METHODS

Data were collected through at-home, in-person interviews from a random sample of inner-city youth (mean age = 15.4 years; 51.5% female; 48.8% White; 22.4% Black; 18.5% Hispanic; 10% Native American) and their parents (n = 1079 parent/youth pairs). Nine youth assets were analysed using multiple logistic regression. Examples of assets youth may possess are: positive role models, family communication, school connectedness, constructive use of time and aspirations for the future. The item used to assess sexual intercourse was 'Have you ever had sexual intercourse ("done it", "had sex", "made love", "gone all the way")?'. Asset/risk behaviour associations that were unique to one of the two strata were the focus of the study.

RESULTS

Thirty-seven per cent of youth spent two or more hours per day home alone. Youth who were supervised had a greater number of unique significant associations between assets and sexual activity than youth who were in the self-care group.

CONCLUSIONS

Youth in supervised settings may be less likely to participate in sexual activity because of the presence of assets. Certain assets may also be important in deterring sexual activity for youth who are in self-care.

A matched case-control study: investigating the relationship between youth assets and sexual intercourse among 13- to 14-year-olds

BACKGROUND

The number of teenagers engaging in sexual intercourse has consistently changed over the past several years. This can become a major challenge when trying to determine why teens continue to have sex. The purpose of this paper was to investigate the relationship between youth assets and sexual intercourse among 13- to 14-year-olds.

METHODS

Cross-sectional data were collected using in-person at-home interviews from a random sample of inner-city neighbourhood 13- to 14-year-old teenagers (n = 64 matched pairs; 36% 13-year-olds, 53% female, 45% white, 28% African-American, 16% Hispanic and 11% Native American). Nine individual youth assets were analysed using conditional logistic regression (matching for several demographic variables) to assess the association between assets and abstinence in younger teens.

RESULTS

Conditional logistic regression analyses showed that two assets, positive Peer Role Models [odds ratios (OR) = 4.67, 95% confidence intervals (CI) = 1.93, 11.27] and Use of Time (Religion) (OR = 2.20, 95% CI = 1.04, 4.65), were significantly related (P < 0.05) to younger teens never having engaged in sexual activity.

CONCLUSION

These findings suggest, when considering abstinence behaviour, involvement in religious activities and having positive peer role models appear to be protective factors related to delaying sexual intercourse among teens aged 13-14 years.

Gain-of-function mutation in Nav1.7 in familial erythromelalgia induces bursting of sensory neurons

Erythromelalgia is an autosomal dominant disorder characterized by burning pain in response to warm stimuli or moderate exercise. We describe a novel mutation in a family with erythromelalgia in SCN9A, the gene that encodes the Na(v)1.7 sodium channel. Na(v)1.7 produces threshold currents and is selectively expressed within sensory neurons including nociceptors. We demonstrate that this mutation, which produces a hyperpolarizing shift in activation and a depolarizing shift in steady-state inactivation, lowers thresholds for single action potentials and high frequency firing in dorsal root ganglion neurons. Erythromelalgia is the first inherited pain disorder in which it is possible to link a mutation with an abnormality in ion channel function and with altered firing of pain signalling neurons.

Spindle and slow wave rhythms at slow wave sleep transitions are linked to strong shifts in the cortical direct current potential

Electroencephalographic activity at the transition from wakefulness to sleep is characterized by the appearance of spindles (12-15 Hz) and slow wave rhythms including delta activity (1-4 Hz) and slow oscillations (0.2-1 Hz). While these rhythms originate within neocortico-thalamic circuitry, their emergence during the passage into slow wave sleep (SWS) critically depends on the activity of neuromodulatory systems. Here, we examined the temporal relationships between these electroencephalogram rhythms and the direct current (DC) potential recorded from the scalp in healthy men (n=10) using cross-correlation analyses. Analyses focused on transitions from wakefulness to SWS in the beginning of the sleep period, and from SWS to lighter sleep and rapid eye movement (REM) sleep at the end of the first sleep cycle. For spindle, delta and slow oscillatory activity strong negative correlations with the DC potential were found at the transition into SWS with peak correlation coefficients (at zero time lag) averaging r=-0.81, -0.88 and -0.88, respectively (P<0.001). Though slightly lower, distinct negative correlations between these measures were also found at the transition from SWS to REM sleep (-0.78, -0.77 and -0.77, respectively, P<0.001). Fast oscillatory activity in the beta frequency band (15-25 Hz) was correlated positively with the DC potential (r=+0.75, P<0.05, at the passage to SWS). Data indicate close links between increasing spindle, delta and slow oscillatory activity and the occurrence of a steep surface negative cortical DC potential shift during the transition from wake to SWS. Likewise, a DC potential shift toward surface positivity accompanies the disappearance of these oscillatory phenomena at the end of the non-REM sleep period. The DC potential shifts may reflect gradual changes in extracellular ionic (Ca2+) concentration resulting from the generation of spindle and slow wave rhythms, or influences of neuromodulating systems on cortical excitability thereby controlling the emergence of cortical spindle and slow wave rhythms at SWS transitions.

Women with HIV infection: a model of university-based care, training and research

The growth of human immunodeficiency virus type-1 (HIV) infection among women in the USA has been coincident with an international momentum to better address the specific health care needs of women. This paper provides an overview of a demonstration model for comprehensive HIV care of adolescent and adult women in an academic setting. The paper contains a descriptive summary of a university-based demonstration model of comprehensive care for women with HIV infection. During 1997-1998, there were 279 urban and rural Midwest adolescent and adult women with HIV infection in care at this model programme. Medical care encompassed subspecialty HIV care, obstetrical and gynaecological care, primary care of non-HIV comorbidities, mental health assessments and family planning in a safe, university-based environment. For 279 women during the two-year period, health services included the detection and treatment of sexually transmitted diseases (56%) and cervical dysplasia (35%), perinatal care (12%) and screening and referral for substance abuse treatment (30%). There was no mother-to-child HIV transmission among 33 pregnant women enrolled in the Center prior to delivery, and transmission by three of nine women enrolled after delivery. Only 167 (60%) women were compliant with biannual medical visits during 1997-1998. Integral to the health services delivery was the provision of ancillary support services intended to enhance optimal medical care for this cohort of women. This university-based model of care also incorporated HIV provider training and formative HIV research. Structured medical and public health experiential learning opportunities occurred for medical and social work students, medicine residents, infectious diseases fellows, nurses and other professional health care workers. Clinical investigations of adolescent and adult women have complemented care and training, with funded research in HIV medication adherence and health services research. In follow-up, 71% of these women remained active in care in 1999. Retention of vulnerable populations in care may be a big challenge over the next decade, despite the availability of potent antiretroviral therapies.

Changes in immune cell counts and interleukin (IL)-1beta production in humans after a somnogenically active growth hormone-releasing hormone (GHRH) administration

Growth hormone-releasing hormone (GHRH) has been shown to enhance slow-wave sleep (SWS) and non-rapid eye movement sleep in animals and humans. In animals the somnogenic effect of interleukin (IL)-1beta appears to be mediated by GHRH. Neuroimmunological interactions in sleep are most frequently studied in humans by sleep deprivation or by cytokine administration. The present study, in contrast, investigates in humans the effect of enhanced sleep through GHRH administration on selected immune parameters. Results reveal that a single intravenous bolus of 50 microg GHRH which enhanced SWS stage 4 in the first half of the night suppressed circulating suppressor T cell (CD3+/CD8+) numbers, with a similar tendency for B cells (CD19+) and suppressed mitogen-stimulated IL-1beta production. When the same amount of GHRH was administered distributed across five repetitive boluses of 10 microg GHRH within 1 h, neither corresponding sleep nor immune parameters were changed significantly compared to placebo. These data suggest that GHRH can modulate immune functions through brain mechanisms which are also involved in the regulation of sleep.