Predictors for achieving optimal sleep in healthy children: Exploring sleep patterns in a sleep extension trial

STUDY OBJECTIVES

Earlier bedtimes can help some children get more sleep, but we don't know which children, or what features of their usual sleep patterns could predict success with this approach. Using data from a randomized crossover trial of sleep manipulation, we sought to determine this.

METHODS

Participants were 99 children aged 8-12years (49.5% female) with no sleep disturbances. Sleep was measured by actigraphy at baseline and over a restriction or extension week (1 hour later or earlier bedtime respectively), randomly allocated and separated by a washout week. Data were compared between baseline (week 1) and extension weeks only (week 3 or 5), using linear or logistic regression analyses as appropriate, controlling for randomization order.

RESULTS

One hour less total sleep time than average at baseline predicted 29.7 minutes (95% CI: 19.4, 40.1) of sleep gained and 3.45 (95% CI: 1.74, 6.81) times higher odds of successfully extending sleep by >30 minutes. Per standardized variable, less total sleep time and a shorter sleep period time were the strongest predictors (significant odds ratios (ORs) of 2.51 and 2.28, respectively). Later sleep offset, more variability in sleep timing and lower sleep efficiency also predicted sleep gains. The sleep period time cut-point that optimized prediction of successful sleep gains was <8 hours 28 minutes with 75% of children's baseline sleep in that range.

CONCLUSIONS

Children with a baseline sleep period time <8½ hours a night obtained the most sleep from earlier bedtimes maintained over a week, demonstrating experimentally the value of earlier bedtimes to improve sleep.

CLINICAL TRIALS REGISTRY

Australian New Zealand Clinical Trial Registry, ACTRN12618001671257, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=367587&isReview=true.

Where does the time go when children don't sleep? A randomized crossover study

OBJECTIVE

This study aimed to describe how mild sleep deprivation in children changes time spent physically active and sedentary.

METHODS

In 2018 through 2020, children (n = 105) with normal sleep were randomized to go to bed 1 hour earlier (extension) or 1 hour later (restriction) than their usual bedtime for 1 week, each separated by a 1-week washout. Twenty-four-hour movement behaviors were measured with waist-worn actigraphy and expressed in minutes and proportions (percentages). Mixed-effects regression models determined mean differences in time use (95% CI) between conditions. Time gained from sleep lost that was reallocated to other movement behaviors in the 24-hour day was modeled using regression.

RESULTS

Children (n = 96) gained ~49 minutes of awake time when sleep was restricted compared with extended. This time was mostly reallocated to sedentary behavior (28 minutes; 95% CI: 19-37), followed by physical activity (22 minutes; 95% CI: 14-30). When time was expressed as a percentage, the overall composition of movement behavior remained similar across both sleep conditions.

CONCLUSIONS

Children were not less physically active when mildly sleep deprived. Time gained from sleeping less was proportionally, rather than preferentially, reallocated to sedentary time and physical activity. These findings suggest that decreased physical activity seems unlikely to explain the association between short sleep and obesity in children.

Effect of Sleep Changes on Health-Related Quality of Life in Healthy Children: A Secondary Analysis of the DREAM Crossover Trial

IMPORTANCE

Little is known regarding the effect of poor sleep on health-related quality of life (HRQOL) in healthy children.

OBJECTIVE

To determine the effect of induced mild sleep deprivation on HRQOL in children without major sleep issues.

DESIGN, SETTING, AND PARTICIPANTS

This prespecified secondary analysis focused on HRQOL, a secondary outcome of the Daily Rest, Eating, and Activity Monitoring (DREAM) randomized crossover trial of children who underwent alternating weeks of sleep restriction and sleep extension and a 1-week washout in between. The DREAM trial intervention was administered at participants' homes between October 2018 and March 2020. Participants were 100 children aged 8 to 12 years who lived in Dunedin, New Zealand; had no underlying medical conditions; and had parent- or guardian-reported normal sleep (8-11 hours/night). Data were analyzed between July 4 and September 1, 2022.

INTERVENTIONS

Bedtimes were manipulated to be 1 hour later (sleep restriction) and 1 hour earlier (sleep extension) than usual for 1 week each. Wake times were unchanged.

MAIN OUTCOMES AND MEASURES

All outcome measures were assessed during both intervention weeks. Sleep timing and duration were assessed using 7-night actigraphy. Children and parents rated the child's sleep disturbances (night) and impairment (day) using the 8-item Pediatric Sleep Disturbance and 8-item Sleep-Related Impairment scales of the Patient-Reported Outcomes Measurement Information System questionnaire. Child-reported HRQOL was assessed using the 27-item KIDSCREEN questionnaire with 5 subscale scores and a total score. Both questionnaires assessed the past 7 days at the end of each intervention week. Data were presented as mean differences and 95% CIs between the sleep restriction and extension weeks and were analyzed using intention to treat and an a priori difference in sleep of at least 30 minutes per night.

RESULTS

The final sample comprised 100 children (52 girls [52%]; mean [SD] age, 10.3 [1.4] years). During the sleep restriction week, children went to sleep 64 (95% CI, 58-70) minutes later, and sleep offset (wake time) was 18 (95% CI, 13-24) minutes later, meaning that children received 39 (95% CI, 32-46) minutes less of total sleep per night compared with the sleep extension week in which the total sleep time was 71 (95% CI, 64-78) minutes less in the per-protocol sample analysis. Both parents and children reported significantly less sleep disturbance at night but greater sleep impairment during the day with sleep restriction. Significant standardized reductions in physical well-being (standardized mean difference [SMD], -0.28; 95% CI, -0.49 to -0.08), coping in a school environment (SMD, -0.26; 95% CI, -0.42 to -0.09), and total HRQOL score (SMD, -0.21; 95% CI, -0.34 to -0.08) were reported by children during sleep restriction, with an additional reduction in social and peer support (SMD, -0.24; 95% CI, -0.47 to -0.01) in the per-protocol sample analysis.

CONCLUSIONS AND RELEVANCE

Results of this secondary analysis of the DREAM trial indicated that even 39 minutes less of sleep per night for 1 week significantly reduced several facets of HRQOL in children. This finding shows that ensuring children receive sufficient good-quality sleep is an important child health issue.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12618001671257.

Infant Sleep Hazards and the Risk of Sudden Unexpected Death in Infancy

OBJECTIVE

To examine the effects of infant sofa-sleeping, recent use by caregivers of alcohol, cannabis, and/or other drugs, and bed type and pillows, on the risk of sudden unexpected death in infancy (SUDI) in New Zealand.

STUDY DESIGN

A nationwide prospective case-control study was implemented between March 2012 and February 2015. Data were collected during interviews with parents/caregivers. "Hazards" were defined as infant exposure to 1 or more of sofa-sleeping and recent use by caregivers of alcohol, cannabis, and other drugs. The interaction of hazards with tobacco smoking in pregnancy and bed sharing, including for very young infants, and the difference in risk for Māori and non-Māori infants, also were assessed.

RESULTS

The study enrolled 132 cases and 258 controls. SUDI risk increased with infant sofa-sleeping (imputed aOR [IaOR] 24.22, 95% CI 1.65-356.40) and with hazards (IaOR 3.35, 95% CI 1.40-8.01). The SUDI risk from the combination of tobacco smoking in pregnancy and bed sharing (IaOR 29.0, 95% CI 10.10-83.33) increased with the addition of 1 or more hazards (IaOR 148.24, 95% CI 15.72-1398), and infants younger than 3 months appeared to be at greater risk (IaOR 450.61, 95% CI 26.84-7593.14).

CONCLUSIONS

Tobacco smoking in pregnancy and bed sharing remain the greatest SUDI risks for infants and risk increases further in the presence of sofa-sleeping or recent caregiver use of alcohol and/or cannabis and other drugs. Continued implementation of effective, appropriate programs for smoking cessation, safe sleep, and supplying safe sleep beds is required to reduce New Zealand SUDI rates and SUDI disparity among Māori.

Germline ATM variants predispose to melanoma: a joint analysis across the GenoMEL and MelaNostrum consortia

PURPOSE

Ataxia-Telangiectasia Mutated (ATM) has been implicated in the risk of several cancers, but establishing a causal relationship is often challenging. Although ATM single-nucleotide polymorphisms have been linked to melanoma, few functional alleles have been identified. Therefore, ATM impact on melanoma predisposition is unclear.

METHODS

From 22 American, Australian, and European sites, we collected 2,104 familial, multiple primary (MPM), and sporadic melanoma cases who underwent ATM genotyping via panel, exome, or genome sequencing, and compared the allele frequency (AF) of selected ATM variants classified as loss-of-function (LOF) and variants of uncertain significance (VUS) between this cohort and the gnomAD non-Finnish European (NFE) data set.

RESULTS

LOF variants were more represented in our study cohort than in gnomAD NFE, both in all (AF = 0.005 and 0.002, OR = 2.6, 95% CI = 1.56-4.11, p < 0.01), and familial + MPM cases (AF = 0.0054 and 0.002, OR = 2.97, p < 0.01). Similarly, VUS were enriched in all (AF = 0.046 and 0.033, OR = 1.41, 95% CI = 1.6-5.09, p < 0.01) and familial + MPM cases (AF = 0.053 and 0.033, OR = 1.63, p < 0.01). In a case-control comparison of two centers that provided 1,446 controls, LOF and VUS were enriched in familial + MPM cases (p = 0.027, p = 0.018).

CONCLUSION

This study, describing the largest multicenter melanoma cohort investigated for ATM germline variants, supports the role of ATM as a melanoma predisposition gene, with LOF variants suggesting a moderate-risk.

Eating in the absence of hunger in children with mild sleep loss: a randomized crossover trial with learning effects

BACKGROUND

While insufficient sleep duration has emerged as a strong, independent risk factor for obesity, the mechanisms remain unclear. One possibility is greater "eating in the absence of hunger" (EAH) or energy intake beyond the point of satiety, when tired.

OBJECTIVE

The aim was to determine whether mild sleep loss increases EAH in children.

METHODS

A crossover study was undertaken in 105 healthy children (8-12 y) with normal sleep (∼8-11 h/night). After randomization, children went to bed 1 h earlier (sleep extension) or 1 h later (sleep restriction) than their usual bedtime, over 2 intervention weeks separated by a 1-wk washout. At the end of each intervention week, children underwent an EAH feeding experiment involving a preloading meal until satiation, followed by an ad libitum buffet (of highly palatable snacks) to measure EAH, with each food item weighed before and after consumption.

RESULTS

Ninety-three children completed the EAH experiment. There was no evidence of a difference in energy intake from EAH between sleep restriction and extension conditions when analyzed as a crossover design. However, a learning effect was found, with children eating significantly less (-239 kJ; 95% CI: -437, -41 kJ; P = 0.018) during the preload phase and significantly more (181 kJ; 95% CI: 38, 322 kJ; P = 0.013) in the ad libitum phase in the second week. No significant differences were seen using an underpowered parallel analysis for energy intake during the ad libitum phase when sleep deprived (106 kJ; 95% CI: -217, 431 kJ; P = 0.514).

CONCLUSIONS

Our findings suggest that measuring a difference in eating behavior in relation to sleep proved unsuitable using the EAH experiment in a crossover design in children, due to a learning effect. This trial was registered at the Australian New Zealand Clinical Trials Registry (http://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=367587&isReview=true) as ACTRN12618001671257 .

Obstructive sleep apnea risk factors and symptoms in children with a known parental obstructive sleep apnea diagnosis

OBJECTIVE

To document symptoms and risk factors of obstructive sleep apnea (OSA) in children who have a parent diagnosed with OSA and compare them to an age and sex matched sample where parents are low risk for OSA.

METHODS

We recruited 25 children with a parent diagnosed with OSA (P-OSA) and 29 age and gender matched children from the community whose parents scored low risk for OSA (P-NOSA). Comparisons were made using the OSA-18 questionnaire, anthropometric measurements, and mallampati score. Statistical analysis included t-tests for OSA-18 score and BMI measures and non parametric analysis for mallampati score. OSA-18 domain scores were analysed using T-test and Bonferroni correction for multiple comparisons.

RESULTS

Fifty-six percent of the P-OSA group had a mallampati score of III/IV compared to 11% in the P-NOSA sample (p = 0.005). There was a significant difference in BMI between the P-OSA sample (mean ± SD 19.5 ± 5.7 kg/m²) and the P-NOSA sample (16.95 ± 2.08 kg/m², p = 0.002). Forty-four percent of P-OSA children were found to be either overweight or obese (BMI z-score). None of the P-NOSA children fell into this category. No significant difference was found between the P-OSA and P-NOSA samples on the OSA-18 score (P-OSA 36.5 ± 8.1, P-NOSA 29.2 ± 9.1, p = 0.07). Five children in the P-OSA sample scored >60 but no P-NOSA children scored >60.

CONCLUSIONS

This study suggests that children with a parent diagnosed with OSA are more likely to have risk factors of pediatric OSA compared to age and sex matched children of parents without OSA but do not have more symptoms.

The effect of mild sleep deprivation on diet and eating behaviour in children: protocol for the Daily Rest, Eating, and Activity Monitoring (DREAM) randomized cross-over trial

BACKGROUND

Although insufficient sleep has emerged as a strong, independent risk factor for obesity in children, the mechanisms by which insufficient sleep leads to weight gain are uncertain. Observational research suggests that being tired influences what children eat more than how active they are, but only experimental research can determine causality. Few experimental studies have been undertaken to determine how reductions in sleep duration might affect indices of energy balance in children including food choice, appetite regulation, and sedentary time. The primary aim of this study is to objectively determine whether mild sleep deprivation increases energy intake in the absence of hunger.

METHODS

The Daily, Rest, Eating, and Activity Monitoring (DREAM) study is a randomized controlled trial investigating how mild sleep deprivation influences eating behaviour and activity patterns in children using a counterbalanced, cross-over design. One hundred and ten children aged 8-12 years, with normal reported sleep duration of 8-11 h per night will undergo 2 weeks of sleep manipulation; seven nights of sleep restriction by going to bed 1 hr later than usual, and seven nights of sleep extension going to bed 1 hr earlier than usual, separated by a washout week. During each experimental week, 24-h movement behaviours (sleep, physical activity, sedentary behaviour) will be measured via actigraphy; dietary intake and context of eating by multiple 24-h recalls and wearable camera images; and eating behaviours via objective and subjective methods. At the end of each experimental week a feeding experiment will determine energy intake from eating in the absence of hunger. Differences between sleep conditions will be determined to estimate the effects of reducing sleep duration by 1-2 h per night.

DISCUSSION

Determining how insufficient sleep predisposes children to weight gain should provide much-needed information for improving interventions for the effective prevention of obesity, thereby decreasing long-term morbidity and healthcare burden.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12618001671257 . Registered 10 October 2018.

Comparison of 12-hour and 24-hour oximetry recordings in preterm infants

AIM

To compare the overnight 12-hour oximetry component of 24-hour oximetry recordings with the complete 24-h recording in terms of cardiorespiratory status data in preterm infants.

METHODS

Preterm infants from the Wellington neonatal intensive care unit underwent a 24-h pulse oximetry recording immediately prior to discharge home. Each recording was edited to resemble a 12-h overnight recording and compared to the full 24-h recording. Differences in a range of cardiorespiratory variables were assessed as to whether they were statistically significant and, if so, likely to be clinically significant.

RESULTS

The nadirs for heart rate and SpO₂ (both P < 0.001), the time spent <80% SpO₂ (P = 0.017) and highest heart rate (P < 0.001) were significantly different between the two recordings. Only the heart rate nadir differed by more than 5%, suggesting that this may be of clinical significance (median (interquartile range) 54 (28-69) for 24-h recording vs. 78 (54-96) for 12-h recording).

CONCLUSION

The 24-h oximetry reports were clinically similar to 12-h recordings for the majority of variables, and therefore, we suggest that 12-h oximetry studies are sufficient for determining cardiorespiratory status in infants.

The influence of bed-sharing on infant physiology, breastfeeding and behaviour: A systematic review

This review aimed to better understand the underlying physiology of the risks and benefits of bed-sharing. Eight databases were searched using terms relating to adult-infant/baby, bed-sharing/co-sleeping combined with outcome terms for physiology, sleep, cardiovascular, respiratory, temperature and behaviour. Of 836 papers identified, 59 papers representing 48 cohorts met inclusion criteria. Objective data using various methodologies were available in 27 papers and subjective data in 32 papers. Diverse measures were reported using variable definitions of bed-sharing. Identified physiological and behavioural differences between bed-sharing and cot-sleeping included increased behavioural arousals, warmer in-bed temperatures and increased breastfeeding duration in bedshare infants as well as differences in infant overnight sleep architecture, cardiorespiratory control and cortisol responses to stress. We concluded that many differences are context-specific, and dependent on the subjective view of the parents and their cultural values. Objective risk arises if the infant is unable to mount an appropriate physiological or behavioural response to their micro-environment. More studies in the bed-sharing setting are needed to identify infant risk, the potential benefits of a safer environment, and how bed-sharing interacts with infant care practices other than sleep.

Relationship between parent knowledge of child sleep, and child sleep practices and problems: A pilot study in a children's hospital cohort

AIM

To describe parent reports of sleep practices, and examine associations with parent knowledge of child sleep, and whether children's sleep practices differ between parents who underestimated, overestimated or accurately estimated children's sleep needs.

METHODS

Parents of children aged 2-12 years (n = 115) attending hospital inpatient or day wards were approached and asked to report child sleep routines, sleep problems, parent education, household income and parent knowledge of child sleep via questionnaire.

RESULTS

Younger age was associated with earlier bedtimes and wake times, shorter sleep latencies, longer sleep durations and greater sleep problems (P < 0.05). Parents from higher income homes reported earlier bedtimes and wake times, shorter sleep latencies and fewer sleep problems (P < 0.05). Parents with higher education reported shorter sleep latencies (P < 0.05). Parents with greater knowledge about child sleep reported earlier weekday and weekend bedtimes (r _s  ≥ 0.26) and wake times (r _s  ≥ 0.21) and greater consistency between their child's weekend and weekday sleep routines (P < 0.05). In comparison with parents who correctly estimated their child's sleep needs: parents who underestimated reported later weekday bedtimes (on average, 46 min), and longer sleep latencies (17 min); parents who overestimated reported longer sleep latencies (22 min). These findings remained significant when controlling for child age (P < 0.05).

CONCLUSION

Parents with increased sleep knowledge, higher incomes and higher levels of education were more likely to report earlier bedtimes, wake times and more consistent sleep routines for their children.

Oximetry for preterm infants at neonatal discharge: What is current practice in New Zealand and Australia?

AIM

The aim of the study was to survey level 2 and 3 neonatal units in Australasia to determine the prevalence of oximetry studies at discharge for preterm infants, how these oximetry studies are performed, and which measures are included in an oximetry report.

METHODS

A 10-question online survey was created using Survey Monkey regarding use of predischarge oximetry and e-mailed to 46 neonatal units (all level 2 and three units in NZ and all level 3 units in Australia).

RESULTS

The response rate was 59% (27/46) with a NZ response rate of 78% (18/23). There was variation in the groups of infants receiving predischarge oximetry studies, with one fifth of responding neonatal units never performing oximetry at discharge. Of the units using predischarge oximetry screening, infants being discharged home on supplemental oxygen were the only group for which all units perform predischarge oximetry. Masimo (Masimo, Irvine, California, USA) is the most common oximeter brand and profox Associates, Inc. (PROFOX Associates, Inc., Escondido, CA 92025, USA) the most common analysis software used. Measures included in oximetry reports vary between units, with profox Associates, Inc.'s default event definition of 'a drop in saturation by four or more' being the most commonly reported desaturation definition.

CONCLUSIONS

These findings indicate a need for guidelines to standardise preterm infant oximetry monitoring at neonatal discharge. Further research is required to determine the utility of predischarge oximetry and to establish which infants should be screened.

Sudden unexpected death in infancy: biological mechanisms

Sudden unexpected death in infancy (SUDI) covers both explained and unexplained deaths. Unexplained cases or SIDS are likely to have multiple neural mechanisms contributing to the final event. The evidence ranges from subtle physiological signs related to autonomic control, to findings at autopsy of altered neurotransmitter systems, including the serotonergic system, a network that has an extensive homeostatic role in cardio-respiratory and thermoregulatory control. Processes may be altered by the vulnerability of the infant due to age, poor motor ability, or a genetic predisposition. The fatal event may occur in response to an environmental stress. A single final physiological route to death seems unlikely. An understanding of the reasons for explained SUDI also reminds us that a thorough investigation is required after each death occurs.

Current definitions for neonatal apnoea: are they evidence based?

Apnoea is defined as cessation of breathing with implicit pathophysiology. This review considers definitions of neonatal apnoea currently available and explores the evidence to support their use. For preterm and term infants, apnoea definitions appear arbitrary, are not supported by guidelines and vary from study to study. Although most alarms on infant breathing monitors are set to alert after a respiratory pause >20s duration is detected, this time period is the equivalent of 17 missed breaths in a preterm infant. Apnoea is likely to be better defined by associated consequence than by pause duration alone in this age group; however, the degree of change in heart rate or oxygen saturation that defines a respiratory pause as pathological is yet to be defined. Further research is required to determine the characteristics that differentiate respiratory events of clinical consequence from normal respiratory variability in term and preterm infants.

Sleep position does not appear to influence the risk of extreme cardiorespiratory events in vulnerable infants

Implications for practice and research: Extreme cardiorespiratory events can be documented during sleep and are more common in immature preterm infants. The supine sleep position does not appear to decrease the risk of Sudden Infant Death Syndrome (SIDS) by decreasing the risk of extreme cardiorespiratory events in vulnerable infants. Reasons for the physiological advantage of the supine sleep position remain speculative and require ongoing study despite decreases in SIDS death rates in recent years.

Effect of position on oxygen saturation and requirement in convalescent preterm infants

AIMS

To document the effect of position on oxygen saturation and changes in oxygen requirement in convalescent preterm infants.

METHODS

Twelve infants born ≥24 and ≤32 weeks gestation, extubated and without congenital anomaly were studied using nap polysomnography in prone and supine, twice weekly until discharge. Mean oxygen saturation (SpO(2)), minimum SpO(2) , mean minimum SpO(2) and time with SpO(2) < 90% were measured in active sleep.

RESULTS

Eight male and four female infants [median gestation 28 (24-31) weeks and median birthweight 1059 (715-1840) g] had 39 studies. For 21 of 39 studies, the infant was on respiratory support. Four infants had chronic lung disease (CLD). SpO(2) varied with postmenstrual age (PMA) (p = 0.003) but not with position (p = 0.36), and PMA did not influence the effect of position on SpO(2) (p = 0.19). SpO(2) was lower for those with CLD (p < 0.0001) and those on respiratory support (p < 0.001), but there was no effect of position (p = 0.97 and p = 0.67, respectively). From 36 weeks PMA, a change to supine did not increase oxygen requirement.

CONCLUSION

In preterm infants, PMA and residual respiratory disease have greater effects on oxygenation than position. A supine sleep position is not disadvantageous for preterm infants at discharge.

Respiratory events in preterm infants prior to discharge: with and without clinically concerning apnoea

PURPOSE

This study aimed to determine the characteristics of respiratory events in preterm infants with clinically concerning apnoea at or beyond 35 weeks postmenstrual age and to compare these findings with a group of preterm infants ready for discharge, without clinically concerning apnoea.

METHODS

Infants born at <32 weeks of gestation and who underwent nap polysomnography at or beyond 35 weeks corrected age prior to discharge were included. Cases were preterm infants with clinically concerning apnoea, and control infants were preterm infants asymptomatic for apnoea. Infants with upper airway obstruction, congenital malformations or apnoea associated with sepsis were excluded. Studies were retrospectively reviewed for length, type and frequency of apnoea. The relationship between sleep state and changes in oxygen saturation was compared between groups. Peri-natal and demographic data were also compared.

RESULTS

Data were complete for 16 case and 18 control infants. Gestational age was similar at birth and at time of study, but cases had a lower birth weight (p = 0.04) and higher weight at study (p = 0.04). There were no group differences in the mean duration, type or numbers of apnoea. The duration of the longest apnoea was greater in case infants (17.4 s vs. 12.3 s, p = 0.02). Lowest oxygen saturation (p < 0.05) and average minimum oxygen saturation (p < 0.05) were lower in case infants.

CONCLUSIONS

Preterm infants with clinically concerning apnoea have similar amounts and types of apnoea but lower oxygen saturation after apnoea compared with controls. The use of oxygen saturation monitoring is more useful than respiratory monitoring alone in recognising these events.

Association of MC1R variants and host phenotypes with melanoma risk in CDKN2A mutation carriers: a GenoMEL study

Background

Carrying the cyclin-dependent kinase inhibitor 2A (CDKN2A) germline mutations is associated with a high risk for melanoma. Penetrance of CDKN2A mutations is modified by pigmentation characteristics, nevus phenotypes, and some variants of the melanocortin-1 receptor gene (MC1R), which is known to have a role in the pigmentation process. However, investigation of the associations of both MC1R variants and host phenotypes with melanoma risk has been limited.

Methods

We included 815 CDKN2A mutation carriers (473 affected, and 342 unaffected, with melanoma) from 186 families from 15 centers in Europe, North America, and Australia who participated in the Melanoma Genetics Consortium. In this family-based study, we assessed the associations of the four most frequent MC1R variants (V60L, V92M, R151C, and R160W) and the number of variants (1, ≥2 variants), alone or jointly with the host phenotypes (hair color, propensity to sunburn, and number of nevi), with melanoma risk in CDKN2A mutation carriers. These associations were estimated and tested using generalized estimating equations. All statistical tests were two-sided.

Results

Carrying any one of the four most frequent MC1R variants (V60L, V92M, R151C, R160W) in CDKN2A mutation carriers was associated with a statistically significantly increased risk for melanoma across all continents (1.24 × 10⁻⁶ ≤ P ≤ .0007). A consistent pattern of increase in melanoma risk was also associated with increase in number of MC1R variants. The risk of melanoma associated with at least two MC1R variants was 2.6-fold higher than the risk associated with only one variant (odds ratio = 5.83 [95% confidence interval = 3.60 to 9.46] vs 2.25 [95% confidence interval = 1.44 to 3.52]; P_trend = 1.86 × 10⁻⁸). The joint analysis of MC1R variants and host phenotypes showed statistically significant associations of melanoma risk, together with MC1R variants (.0001 ≤ P ≤ .04), hair color (.006 ≤ P ≤ .06), and number of nevi (6.9 × 10⁻⁶ ≤ P ≤ .02).

Conclusion

Results show that MC1R variants, hair color, and number of nevi were jointly associated with melanoma risk in CDKN2A mutation carriers. This joint association may have important consequences for risk assessments in familial settings.

Sudden unexpected infant death and bedsharing: referrals to the Wellington Coroner 1997-2006

AIMS

To describe the factors associated with sudden unexpected infant deaths, for which there was no clear medical diagnosis, referred to the Wellington-based coronial paediatric pathology service over the decade from 1997 to 2006.

METHODS

The postmortem report, Police 47 file, Coroner's findings and deceased infant's medical records were used to create a profile for each sudden and unexpected infant death.

RESULTS

There were 64 deaths in the period: 54 of these occurred during sleep and did not have a clear medical diagnosis. Maori and Pacific infants and infants from low decile areas were over-represented in the group. The majority (88.7%) of infants were < 6 months of age at death. Overall, 50% of infants had been placed to sleep in a non-recommended sleep position and 38% usually slept in a non-recommended location. Bedsharing was associated with 53.7% of deaths. There was a significant association between bedsharing and being found dead on a Sunday morning (p=0.04).

CONCLUSION

Sudden unexpected death in infancy is associated with unsafe sleep environments and sleep positions. Every effort should be made to ensure that information about safe infant sleep practices reaches the caregivers of those particularly at risk.

Car seat test for preterm infants: comparison with polysomnography

OBJECTIVES

To monitor preterm infants in a cot and a car seat and compare an observed car seat trial with polysomnography (PSG).

DESIGN

Non-randomised controlled trial.

SETTING

Regional neonatal unit.

PATIENTS

Preterm infants before discharge.

INTERVENTIONS

Nap PSG respiratory and sleep variables were measured including gastro-oesophageal pH. Nurse observations included respiratory distress, apnoea measured by apnoea alarm, oxygen saturation and heart rate. Infants were studied supine in a cot and then in a car seat. Nursing observations were compared with PSG during the car seat trial only. Criteria for failure of the PSG and observed tests were predefined.

MAIN OUTCOME MEASURES

Difference in respiratory instability between cot and car seat. Concurrence regarding failure of the car seat trial between nurse-observed data and PSG.

RESULTS

20 infants (median gestation 33 weeks (range 28-35 weeks; median postmenstrual age (PMA) at study 36.5 weeks (range 35-38 weeks)) were studied. There were sufficient car seat data on 18 infants for comparison. There were fewer central apnoeas and arousals in the cot than the car seat (p = 0.047 and p = 0.024, respectively). Airway obstruction was not more common in the car seat. Younger PMA at time of study predicted failure in both car seat (p = 0.022) and cot (p = 0.022). The nurse-observed test had low sensitivity for predicting PSG failure but more accurately predicted airway obstruction on PSG.

CONCLUSIONS

Immature infants exhibit respiratory instability in cots and car seats. A car seat test does not accurately detect all adverse events during sleep in the seat.

Neonatal death after hypoxic ischaemic encephalopathy: does a postmortem add to the final diagnoses?

BACKGROUND

Case review after fatal perinatal asphyxia may have medicolegal implications. Accurate diagnosis of cause of death is therefore essential.

OBJECTIVE

To determine consent rate and utility of autopsy after fatal grade III hypoxic ischaemic encephalopathy (HIE) presumed to be secondary to birth asphyxia.

DESIGN

A retrospective clinical review from January 1995 to December 2002.

SETTING

Regional tertiary referral neonatal unit, Wellington, New Zealand.

POPULATION

Inclusion criteria were gestation >/=37 weeks, resuscitation after delivery and clinical course of grade III HIE. Exclusions were a recognised major lethal malformation.

METHODS

Review of clinical records including the autopsy report.

MAIN OUTCOME MEASURES

Consent for autopsy, change in diagnosis after autopsy.

RESULTS

Twenty-three infants died during the time period with a major diagnosis of grade III HIE. Three did not meet inclusion criteria. Of the remaining 20, 11 were female. Median gestation at birth was 40 weeks (range 38-42 weeks) and median birth weight was 3568 g (range 2140-4475 g). In 8/17 of the infants for whom length and head measurements were available, the Ponderal Index suggested intrauterine growth retardation. The 16/20 infants had an autopsy. Four of these were Coroner's cases giving an autopsy rate of 80% with a rate by consent of 60%. In 10 (62.5%) infants, significant new information was added to the clinical diagnoses.

CONCLUSIONS

Neonatal HIE is a symptom rather than a final clinical diagnosis. A full autopsy is required to fully explore the reasons for fatal neonatal HIE and may provide information that is important medicolegally.

Autopsy after death due to extreme prematurity

Autopsy reports for 29 very preterm infants dying at <28 days of age were reviewed. New findings were discovered in 79% and resulted in a significant change in diagnoses in 28%. Iatrogenic lesions were identified in 41% of cases and were the main cause of death in 14%.

Prone or supine for infants with chronic lung disease at neonatal discharge?

OBJECTIVE

To determine whether infants with chronic lung disease (CLD), ready for neonatal unit discharge, maintain cardiorespiratory stability while sleeping supine.

METHODS

Subjects were 15 infants born < 32 weeks gestational age (GA) and ready for discharge from the regional tertiary neonatal intensive care unit. Polysomnography recordings of sleep state, heart rate, arterial oxygen saturation, respiratory effort and nasal/oral airflow were taken prone and supine for up to 3 h post feed with the first position randomly allocated. The main outcome measures were oxygen saturation and apnoea hypopnoea index (AHI).

RESULTS

Seven infants (median GA 27 weeks, birthweight 945 g) had CLD and eight infants (median GA 29 weeks, birthweight 1160 g) did not. CLD infants were more mature at study than non-CLD infants (median 39 vs 36 weeks, P = 0.019). Neither oxygen saturation nor AHI were position dependent and no group differences were noted with respect to CLD status. There was a significant interaction of GA and sleep position with less-mature infants spending less time in quiet sleep (QS) in supine position (P = 0.006). These less-mature infants also had a higher AHI (P = 0.033). As expected, the AHI and arousal index (AI) were higher in active sleep (P < or = 0.001, P = 0.013, respectively) and mean oxygen saturation was lower (P = 0.001).

CONCLUSIONS

The supine position appears appropriate for very preterm infants with CLD going home from the neonatal unit. Respiratory instability on neonatal discharge is more likely to be associated with immaturity than CLD.

Lymphatic vessel density is significantly increased in melanoma

BACKGROUND

Melanoma is well known for its ability to involve regional lymph nodes in the early stage. However, the presence of lymphangiogenesis in melanoma is still controversial due to lack of lymphatic-specific markers. The purpose of this study was to determine the intra- and peritumoral lymphatic vessel density (LVD) using a novel lymphatic vessel-specific marker D2-40 and compare it to general vessel density (GVD) as determined by CD31 immunostaining in a series of melanocytic lesions.

METHODS

The intra- and peritumoral GVD and LVD were examined by immunohistochemistry using D2-40 and CD31 antibodies in a series of melanocytic lesions.

RESULTS

We found significantly higher intratumoral LVD in melanomas as compared to either common acquired or dysplastic nevi (p < 0.01). Although peritumoral LVD in melanoma and malignant melanoma in situ was higher compared to nevi, the difference did not reach statistical significance (p = 0.059). There was no significant difference in GVD among the various groups of melanocytic lesions.

CONCLUSIONS

Our results show that intratumoral LVD is significantly increased in melanomas compared to benign nevi. The higher intratumoral lymphatic density in invasive melanomas suggests that melanoma cells might promote lymphangiogenesis. In addition, assessment of intratumoral LVD may be potentially useful in the differential diagnosis of melanocytic lesions.

Fractal characteristics of breath to breath timing in sleeping infants

We examined interbreath interval (IBI) time series of 19 term infants during active and quiet sleep for fractal properties using Fano factor analysis. For each time series we calculated the fractal exponent (alpha), comparing alpha for the original time series with two forms of surrogate data, a temporally independent surrogate set and an autoregressive surrogate set. alpha values were normally distributed between 0.79 and -0.22, and did not differ with sleep state. The fractal characteristics of the original time series were not retained in the temporally independent surrogate time series indicating that the distribution of intervals alone was not fractal, but were retained using autoregressive surrogates with an order of 10, suggesting that the fractal properties of the IBI time series were related to correlations between successive breaths. These observations suggest that some of the respiratory variability that occurs during sleep in infants, which in the past has been regarded as stochastic noise, may be the product of deterministic processes.

Interobserver reproducibility of ulceration assessment in primary cutaneous melanomas

In the recently revised melanoma staging system proposed by the American Joint Committee on Cancer (AJCC), ulceration assessment by the pathologist is a pivotal parameter. Patients upstaged because of ulceration might be included in adjuvant trials conducted in AJCC stage II melanoma patients. Therefore, accuracy based on interobserver reproducibility for melanoma ulceration assessment is crucial for proper clinical management. In some cases, it is extremely difficult, even for an experienced pathologist, to distinguish between trauma-induced ulceration, artifact and tumoral ulceration. Whether this difficulty may be resolved by the use of a more precise definition of ulceration has not been evaluated. Therefore, we have proposed a refined definition of melanoma ulceration and we tested whether this definition might improve the interobserver interpretative reproducibility of ulceration in primary cutaneous melanomas. The results of this study support the need for a more precise definition of melanoma ulceration that rules out biopsy trauma or processing artifact and could be incorporated into a standardised pathology worksheet for reporting primary melanomas.

A versatile method for the removal of melanin from ribonucleic acids in melanocytic cells

Melanin pigments often co-purify during preparation of nucleic acids from cells or tissues of melanocytic origin. Contaminating melanin can severely impede subsequent analyses of RNA. We attempted to eliminate melanin in RNA preparations using selected gel matrices. We show here that co-purified melanin pigments can be largely eliminated from RNA samples after passing through polyacrylamide-based beads (Bio-Gel P-60). After isolation from the pigment-containing cells or tissues, RNA was subsequently processed through batch or column purification under acidic pH conditions. The resulting RNA was devoid of contaminating melanin pigments and amenable to molecular reactions such as polymerase chain reaction and cDNA synthesis by reverse transcriptase. Although the process results in some loss of input RNA, this purification procedure is simple, robust and can easily be adopted in any laboratory for the molecular analysis of RNA that requires removal of melanin contamination.

Rarity of CDK4 germline mutations in familial melanoma

To date, two genes have been implicated in melanoma pathogenesis. The first, CDKN2A, is a tumour suppressor gene with germline mutations detected in 20% of melanoma-prone families. The second, CDK4, is an oncogene with co-segregating germline mutations detected in only three kindreds worldwide. We examined 16 American melanoma-prone families for mutations in all coding exons of CDK4 and screened additional members of two previously reported families with the Arg24Cys germline CDK4 mutation to evaluate the penetrance of the mutation. No new CDK4 mutations were identified. In the two Arg24Cys families, the penetrance was estimated to be 63%. Overall, 12 out of 12 invasive melanoma patients, none out of one in situ melanoma patient, five out of 13 dysplastic naevi patients, two out of 15 unaffected family members, and none out of 10 spouses carried the Arg24Cys mutation. Dysplastic naevi did not strongly co-segregate with the Arg24Cys mutation. Thus the phenotype observed in melanoma-prone CDK4 families appears to be more complex than just the CDK4 mutation. Both genetic and environmental factors are likely to contribute to the occurrence of melanoma and dysplastic naevi in these families. In summary, although CDK4 is a melanoma susceptibility gene, it plays a minor role in hereditary melanoma.

Locally recurrent malignant melanoma characteristics and outcomes: a single-institution study

Despite improvements in the identification and treatment of melanoma, local recurrence continues to challenge the success of current melanoma therapy. A retrospective analysis of 1,996 patients presenting from 1990 to 1997 at the Pigmented Lesion Group of the University of Pennsylvania was performed to assess clinical characteristics and outcomes of locally recurrent melanoma. The cases were analyzed by chart and pathological slide review. A control group was identified for statistical comparison. The incidence of locally recurrent melanoma during the study period was 2.2%. Lentigo maligna melanoma (LMM) accounted for 37% of the local recurrences. Increased tumor thickness and microsatellites were associated with "early" local recurrence and decreased survival from time of recurrence. Nineteen percent of the local recurrences occurred more than 5 years after the initial definitive treatment. The preponderance of locally recurrent LMM suggests the need for refinements in the techniques of margin identification and surgical excision of LMM. Tumors with increased thickness and microsatellites should receive particularly close attention. Lastly, with nearly 20% of the local recurrences occurring more than 5 years after the initial date of treatment, the authors suggest extending the follow-up time for all melanoma lesions beyond 5 years.

Signs and symptoms of melanoma in older populations

We conducted a descriptive study to assess the relationship between increasing age and the reporting of melanoma signs/symptoms in 634 hospital-based and 624 population-based incident cases of melanoma. Multivariate logistic regression was used to evaluate the relationship between older age (> or = 50 years) and the reporting of melanoma signs/symptoms. Older patients were less likely to report itching and change in elevation of their lesions (P < 0.05). Change in color was also less likely to be reported by older patients, although not statistically significant. Ulceration of the lesion was reported significantly more by older patients (P < 0.05). Older individuals may be less likely to report itching and change in elevation/color of their lesions, but more likely to report ulceration, a symptom associated with advanced disease and poor prognosis. Further research is necessary to provide a better understanding of the development of melanoma in older populations so that new strategies can be explored to improve early detection in this age group.

Incidence of sentinel node metastasis in patients with thin primary melanoma (< or = 1 mm) with vertical growth phase

BACKGROUND

Patients with thin primary melanomas (< or = 1 mm) generally have an excellent prognosis. However, the presence of a vertical growth phase (VGP) adversely impacts the survival rate. We report on the rate of occurrence of nodal metastasis in patients with thin primary melanomas with a VGP who are offered sentinel lymph node (SLN) biopsy.

METHODS

Among 235 patients with clinically localized cutaneous melanomas who underwent successful SLN biopsy, 71 had lesions 1 mm or smaller with a VGP. The SLN was localized by using blue dye and a radiotracer. If negative for tumor by using hematoxylin and eosin staining, the SLN was further examined by immunohistochemistry.

RESULTS

The rate of occurrence of SLN metastasis was 15.2% in patients with melanomas deeper than 1 mm and 5.6% in patients with thin melanomas. Three patients with thin melanomas and a positive SLN had low-risk lesions, based on a highly accurate six-variable multivariate logistic regression model for predicting 8-year survival in stage I/II melanomas. The fourth patient had a low- to intermediate-risk lesion based on this model. At the time of the lymphadenectomy, one patient had two additional nodes with metastasis.

CONCLUSIONS

VGP in a melanoma 1 mm or smaller seems to be a risk factor for nodal metastasis. The risk of nodal disease may not be accurately predicted by the use of a multivariate logistic regression model that incorporates thickness, mitotic rate, regression, tumor-infiltrating lymphocytes, sex, and anatomical site. Patients with thin lesions having VGP should be evaluated for SLN biopsy and trials of adjuvant therapy when stage III disease is found.

E-cadherin expression in melanoma cells restores keratinocyte-mediated growth control and down-regulates expression of invasion-related adhesion receptors

In human epidermis, functional symbiosis requires homeostatic balance between keratinocytes and melanocytes. Compelling evidence from co-culture studies demonstrated a sophisticated, multileveled regulation of normal melanocytic phenotype orchestrated by undifferentiated, basal-type keratinocytes. Keratinocytes control cell growth and dendricity, as well as expression of melanoma-associated cell surface molecules of normal melanocytes. In contrast, melanoma cells are refractory to the keratinocyte-mediated regulation. The loss of regulatory dominance by keratinocytes occurs in concert with down-regulation of E-cadherin expression in melanoma cells. To investigate the potential role of E-cadherin in melanoma-keratinocyte interaction, we transduced E-cadherin-negative melanoma cells with full-length E-cadherin cDNA using an adenoviral vector. Our results show that functional E-cadherin expression in melanoma cells leads to cell adhesion to keratinocytes rendering them susceptible for keratinocyte-mediated control. In a skin reconstruction model, ectopic E-cadherin expression inhibits invasion of melanoma cells into dermis by down-regulating invasion-related adhesion receptors, MelCAM/MUC18 and beta3 integrin subunit, and by induction of apoptosis. Thus, disruption of the E-cadherin-mediated, normal regulatory control from keratinocytes may represent one of the mechanisms accounting for melanocyte transformation.

The effect of selenium supplementation on outcome in very low birth weight infants: a randomized controlled trial. The New Zealand Neonatal Study Group

BACKGROUND

Low selenium (SE) status has been documented in preterm infants and has been suggested to be a risk factor for chronic lung disease.

METHODS

A total of 534 infants with birth weight <1500 g were enrolled in 8 New Zealand centers in a double-blind placebo-controlled randomized trial of SE supplementation from week 1 of life until 36 weeks' postmenstrual age or discharge home. Supplemented infants received 7 microg/kg/d of SE when fed parenterally and 5 microg/kg/d when fed orally. Plasma SE and glutathione peroxidase concentrations were measured in mothers after delivery and in infants before randomization and at 28 days and 36 weeks' postmenstrual age. Primary outcome measures were oxygen dependency at 28 days and total days oxygen dependency.

RESULTS

No significant differences were seen between the groups with respect to primary or secondary outcome measures, with the exception that fewer supplemented infants had an episode of sepsis after the first week of life (P <.038). Mean plasma SE concentrations were 0.33 micromol/L before randomization in both groups and at 28 days had risen in the supplemented group (0.56 micromol/L) but fallen in the control group (0.29 micromol/L) (P <.0001). There was no association between outcome measures and SE concentrations at 28 days or 36 weeks' postmenstrual age. However, lower maternal and infant prerandomization SE concentrations were associated with increased respiratory morbidity.

CONCLUSIONS

Postnatal SE supplementation in very low birth weight infants did not improve neonatal outcome. Further investigation of SE supplementation of mothers from the second half of pregnancy is warranted.

TIA-1 positive tumor-infiltrating lymphocytes in nevi and melanomas

Tumor-infiltrating lymphocytes (TIL) have been shown to be an independent prognostic factor in melanomas. To better characterize the host immune response, we have classified TIL by their immunoreactivity against lymphoid markers in formalin-fixed, paraffin-embedded tissue. Monoclonal antibodies to leukocyte common antigen (LCA) and TIA-1 (a granule-associated protein of cytotoxic T cells and NK cells) were used to immunostain a series of benign nevi, nontumorigenic radial growth phase, and tumorigenic vertical growth phase melanomas and metastases. Among nine nevi, few LCA+ TIL were found, among which rare cells were positive for TIA-1 (mean, 2.0). Five nontumorigenic radial growth phase melanomas also had few total TIL and rare TIA-1+ TIL (mean, 3.4); the nontumorigenic radial growth phase component of seven tumorigenic vertical growth phase melanomas had higher numbers of TIA-1+ TIL (mean, 11). Twelve cases of tumorigenic vertical growth phase melanoma showed a variable but significantly greater number of both LCA+ TIL and TIA-1+ TIL (mean, 30.6). Nine cases of metastatic melanoma had a wide range of variation in LCA as well as in TIA-1+ TIL (mean, 46). Although the mean total number of TIA-1+ TIL increased from nontumorigenic radial growth phase to tumorigenic vertical growth phase to metastases, TIA-1+ as a percentage of TIL declined across these categories of tumor progression (42%, 31%, and 26%, respectively). Our results show that these attributes of TIA-1+ TIL, both increasing total number but decreasing percentage, appear to be a marker of tumor progression of malignant melanomas. In addition, there was significant variability in the number of TIA-1+ TIL among advanced melanomas, raising the possibility that an assessment of TIA-1+ TIL may prove a useful prognostic tool for the evaluation of primary melanomas.

Human melanoma progression in skin reconstructs : biological significance of bFGF

Human skin reconstructs are three-dimensional in vitro models consisting of epidermal keratinocytes plated onto fibroblast-contracted collagen gels. Cells in skin reconstructs more closely recapitulate the in situ phenotype than do cells in monolayer culture. Normal melanocytes in skin reconstructs remained singly distributed at the basement membrane which separated the epidermis from the dermis. Cell lines derived from biologically early primary melanomas of the radial growth phase proliferated in the epidermis and the basement membrane was left intact. Growth and migration of the radial growth phase melanoma cells in the dermal reconstruct and tumorigenicity in vivo were only observed when cells were transduced with the basic fibroblast growth factor gene, a major autocrine growth stimulator for melanomas. Primary melanoma cell lines representing the more advanced stage vertical growth phase invaded the dermis in reconstructs and only an irregular basement membrane was formed. Metastatic melanoma cells rapidly proliferated and aggressively invaded deep into the dermis, with each cell line showing typical invasion and growth characteristics. Our results demonstrate that the growth patterns of melanoma cells in skin reconstructs closely correspond to those in situ and that basic fibroblast growth factor is critical for progression.

Human hair follicle bulge cells are biochemically distinct and possess an epithelial stem cell phenotype

Stem cells are vital for the homeostasis of self-renewing tissues and their manipulation may have wide ranging applications, including gene therapy, wound repair, and tissue transplantation. Although rodent hair follicle stem cells have been localized to the follicle bulge, the location of human hair follicle stem cells is less clear, and their characterization has been hampered by a lack of cellular markers for the bulge area. We demonstrate that the C8/144B monoclonal antibody, originally raised against a CD8 peptide sequence, immunostains the human hair follicle bulge. We show that this antibody recognizes cytokeratin 15 (K15) in keratinocytes, and that K15-positive bulge cells possess a stem cell phenotype characterized by their slowly cycling nature, proliferation at the onset of new hair follicle growth, and high level of beta1 integrin expression. These results localize human hair follicle stem cells to the bulge and suggest that K15 is preferentially expressed in epithelial stem cells.

99mTc-human serum albumin: an effective radiotracer for identifying sentinel lymph nodes in melanoma

Sentinel lymph node (SLN) biopsy has emerged as a novel approach for identifying patients with melanoma and regional nodal micrometastasis who may benefit from full nodal basin resection. To identify the pattern of tumor lymphatic drainage and the SLN, lymphoscintigraphy has been performed using primarily 99mTc-sulfur colloid (SC). In this study, we compare the efficacy of SLN biopsy using 99mTc-human serum albumin (HSA) with SLN biopsy after SC-based lymphoscintigraphy.

METHODS

One hundred and six patients with localized cutaneous melanoma were studied. Lymphoscintigraphy was performed after intradermal injection of HSA in 85 patients and SC in 21 patients. Four patients underwent lymphoscintigraphy twice, once with SC and once with HSA. Dynamic images were acquired for up to 1 h, followed by high-count images of the SLN in various projections so that the most likely site was marked on the skin for biopsy. Intraoperatively, blue dye was injected around the primary site. Twenty-four patients underwent SLN dissection directed by preoperative lymphoscintigraphy and vital blue dye mapping; in the remaining 80 patients, a gamma probe was added intraoperatively to the localization procedure. Two patients underwent mapping with gamma probe alone.

RESULTS

Draining lymphatic basins and nodes were identified by lymphoscintigraphy in all patients. The SLN was identified in 95% of patients when both blue dye and intraoperative gamma probe were used. When 99mTc-HSA was used for imaging, 98% of the SLNs ultimately identified were radiolabeled, and 82% were both hot and blue. Of the SLN recovered with SC, all the nodes were radiolabeled; however, there was only 58% hot and blue concordance. Greater numbers of SLNs were removed in the SC group (median 2.0 versus 1.0, P = 0.02); however, the incidence of micrometastasis was statistically similar in both HSA and SC cohorts. In the 4 patients examined with both tracers, SLN mapping was similar.

CONCLUSION

Although SC has been the radiotracer of choice for SLN mapping in melanoma, HSA appears to be a suitable alternative, with identical success rates. In fact, the higher concordance between hot and blue nodes using HSA suggests superiority of this tracer for this purpose.

Progression-related expression of beta3 integrin in melanomas and nevi

The expression of the beta3 integrin subunit was investigated in 130 fixed, paraffin-embedded specimens of human melanomas and nevi using two different monoclonal antibodies. Expression was not observed in melanocytes and was absent or low in most nevi. In primary melanomas, expression was absent or low in the nontumorigenic radial growth phase, which includes the classes of in situ and microinvasive melanomas. In contrast, expression was high in the tumorigenic or vertical growth phase compartment of many primary melanomas and in most metastatic melanomas. Expression patterns were similar with the two antibodies, SSA6 and SAP, and was membrane-related as well as cytoplasmically expressed. In those nevi that reacted focally, the reactivity tended to occur in the dermal component of neurotized nevi, and in Spitz nevi, where the reactivity was stronger and more diffuse. A few dysplastic nevi showed focal reactivity of the junctional component. These results are consistent with tumor progression-related expression of the beta3 integrin, which is expressed in melanocytic tumors as the alphavbeta3 integrin, having affinity for matrix molecules, including vitronectin and fibronectin. In all melanomas, and in the subset of tumorigenic vertical growth phase melanomas, expression increased with thickness (P < .01). For this reason, and because ligation of this integrin has been shown in vitro to have several properties that may be related to the malignant phenotype, it is likely that expression of this marker may have prognostic value. However, because of its consistent and strong expression in Spitz nevi, the diagnostic utility of this marker will likely be limited.

Hospital admissions in the first year of life in very preterm infants

OBJECTIVE

To analyse hospital readmissions to 1 year in infants < 33 weeks' gestation.

STUDY DESIGN

Cohort of very preterm infants born in Western Australia.

METHODS

Parental social class, history of asthma, race, gestational age, birthweight, sex, severity of respiratory disease and oxygen requirement at 28 days chronic lung disease (CLD), 36 weeks and term, maternal smoking, cohabitation with siblings, breast-feeding duration and hospital readmissions were recorded prospectively.

RESULTS

Data were available for 538 of 560 (96%) infants discharged. Eight died in the first year. Two hundred and twenty-five infants (42%) had 443 readmissions, of which 370 were medical and 73 surgical. Risk factors for medical readmission were Aboriginal race, male sex and CLD. Breast-feeding was protective. Risk factors for surgical admission were male sex, lower gestation, severe hyaline membrane disease, severe CLD and birthweight < 10th centile.

CONCLUSIONS

Readmission is common after very preterm birth. Risk factors for medical and surgical admission differ with CLD being the only perinatal factor associated with both medical and surgical admission.

Cytokeratin 15 expression in trichoepitheliomas and a subset of basal cell carcinomas suggests they originate from hair follicle stem cells

Trichoepitheliomas and many basal cell carcinomas appear to arise from the hair follicle, and in particular from the hair follicle bulge. This histogenesis is suggested from both morphological and immunohistochemical studies on tumor cells and stroma. Epithelial stem cells are thought to be important in tumorigenesis, and we previously localized a population of stem cells to the bulge area of the outer root sheath. We recently identified an anti-CD8 monoclonal antibody (DAKO clone C8/144B) that cross-reacts with cytokeratin 15 (K15), and serves as a specific marker for the bulge. In this study, we screened a series of trichoepitheliomas (n=13), basal cell carcinomas (n=37) and a variety of other skin tumors with this antibody. All trichoepitheliomas (100%) showed keratin 15 expression, while only a subset of basal cell carcinomas (27%) was K15-positive. Epidermal tumors, including squamous cell carcinomas, were K15-negative. Tumors of follicular derivation such as proliferating trichilemmal cysts were also K15-positive, while others such as pilomatricoma were K15-negative. Expression of K15 in trichoepitheliomas, some basal cell carcinomas and other follicular tumors suggests that these tumors are related to hair follicle stem cells in the bulge.