The early lives of the islanders: Stable isotope analysis of incremental dentine collagen from the prehispanic period of the Canary Islands

OBJECTIVES

This study presents isotopic information for incremental dentine collagen and bone bulk collagen from individuals from the Canary Islands (Tenerife and Gran Canaria) to explore dietary differences during childhood life.

MATERIALS AND METHODS

Eight individuals have been studied, which comprises 122 δ15 N and δ13 C incremental dentine measurements and eight bulk bone collagen analyses. A baseline of potentially consumed food sources has been developed for comparative purposes. A food reconstruction using isotopic transferred signals (FRUITS) model of probable contributions of each food source towards the diet of each individual has been developed. All samples but one belongs to the later period of indigenous occupation of the archipelago.

RESULTS

The dentine collagen data are presented in correlated δ13 C and δ15 N plots per individual, showing the isotopic changes throughout time. δ15 N values for each individual tend to be variable whereas δ13 C data are generally more stable with a range of +9.1 to +14‰ for δ15 N and -17.4 to -20.8‰ for δ13 C.

CONCLUSION

The isotopic analysis allows for the reconstruction of eight dietary profiles, which allow us to estimate the different dietary protein sources. The FRUITS model shows different percentages of the primary food sources for each individual. Where both δ13 C and δ15 N are elevated, this could be indicative of a higher marine contribution to the diet. There appear to be two main dietary profiles identifiable in the dataset and these may be related to changes in status or place of residence. Short-term variations in δ13 C and δ15 N and opposing co-variance of isotopic values can be indicative of nutritional stress, although metabolic changes during growth are also considered.

Method of micro-sampling human dentine collagen for stable isotope analysis

RATIONALE

Sampling of dentine for stable carbon (δ¹³ C) and nitrogen (δ¹⁵ N) isotope ratios in the direction of tooth growth allows the study of temporal changes to the diet and physiological stress of an individual during tooth formation. Current methods of sampling permanent teeth using 1 mm increments provide temporal resolution of 6-9 months at best depending on the tooth chosen. Although this gives sufficient sample sizes for reliable analysis by mass spectrometry, sectioning the dentine across the incremental structures results in a rolling average of the isotope ratios. A novel method of incremental dentine collagen sampling has been developed to decrease the collagen increment size to 0.35 mm along the incremental structures, thus reducing averaging and improving the temporal resolution of short-term changes within the δ¹³ C and δ¹⁵ N values.

METHODS

This study presents data for a MicroMill-assisted sampling method that allows for sampling at 0.35 mm width × 1 mm depth increments following the incremental growth pattern of dentine. A NewWave MicroMill was used to sample the demineralised dentine section of modern donated human third molars from Sudan and compared to data from the same teeth using the 1 mm incremental sectioning method 2 established by Beaumont et al. RESULTS: The δ¹³ C and δ¹⁵ N isotopic data showed an increased temporal resolution, with each increment providing data for 2-4 months of dentine formation.

CONCLUSIONS

The data show the potential of this method for studying dietary reconstruction, nutritional stress, and physiological change with greater temporal resolution potentially to seasonal level and with less attenuation of the δ¹³ C and δ¹⁵ N values than was previously possible from human dentine.

Reproductive life histories: can incremental dentine isotope analysis identify pubertal growth, pregnancy and lactation?

BACKGROUND

There are few reliable osteological indicators to detect parity or infer puberty in skeletal remains. Nitrogen (δ¹⁵N) and stable carbon (δ¹³C) isotope ratios in human tissues can be affected by metabolically unbalanced states engendered by pregnancy or rapid growth, offering potential biomarkers.

AIM

This pilot study explores the potential of incremental dentine-collagen isotope ratio analysis to identify puberty and gestation.

SUBJECTS AND METHODS

Incremental dentine δ¹⁵N and δ¹³C profiles were produced by analysing third molars extracted as part of dental treatment of 10 individuals living in Sudan. Demographic and anthropometric data at the time of tooth extraction was available. Medical histories were unknown.

RESULTS

Isotopic signatures potentially related to pubertal growth, with an average δ¹⁵N reduction of 0.78 ± 0.29‰, are indicated. Six isotopic signals suggestive of pregnancy, with an average δ¹⁵N decrease of 0.48 ± 0.22‰, are also observed. The timing, speed and amplitude of post-partum δ¹⁵N patterns seemingly infer infant feeding practices and maternal nutritional status.

CONCLUSION

This pilot study highlights the potential of incremental dentine isotope analysis for the reconstruction of early reproductive histories in skeletal remains. However, controlled studies with a larger human cohort are needed to validate these findings, establish isotopic signals linked to puberty and lactation, and improve chronology accuracy.

An isotope signature for diffuse idiopathic skeletal hyperostosis?

OBJECTIVES

Diffuse idiopathic skeletal hyperostosis (DISH) has recurrently been associated with a rich diet (high in protein and higher trophic level foods); however, very few studies have investigated this link using carbon and nitrogen (δ¹³C and δ¹⁵N) stable isotope analysis. This paper explores the relationship between DISH and diet in two Roman urban communities by analyzing individuals with and without DISH.

MATERIALS AND METHODS

δ¹³C and δ¹⁵N analysis carried out on collagen from 33 rib samples (No DISH: 27; early DISH: 4; DISH: 2) selected from individuals buried at the Romano-British site of Baldock (UK), 41 rib samples (No DISH: 38; early DISH: 3) from individuals from the Catalan Roman site of Santa Caterina (Barcelona, Spain). Additionally, six faunal samples from Baldock and seven from Santa Caterina were analyzed.

RESULTS

Standardized human isotope data from Santa Caterina show high δ¹⁵N probably associated to a diet combining terrestrial resources and freshwater fish. In contrast, isotope results from Baldock suggest a terrestrial-based diet. Individuals with DISH do not show isotopic ratios indicative of rich diet and there is no correlation between stage of DISH development and δ¹³C and δ¹⁵N.

CONCLUSION

The results of this study suggest that individuals with DISH followed a similar or isotopically similar diet as those individuals without DISH in Baldock and in Santa Caterina and therefore, while DISH may have been influenced by individual's dietary habits, this is not reflected in their isotopic signature.

Children of the abyss: Investigating the association between isotopic physiological stress and skeletal pathology in London during the Industrial Revolution

OBJECTIVE

This project sought to investigate whether an association may be observed between isotopic stress indicators and skeletal evidence of pathological conditions.

MATERIALS

Deciduous and permanent teeth of 15 non-adults from two contemporaneous mid-19th century London burial grounds (City Bunhill, Lukin Street).

METHODS

δ¹³C and δ¹⁵N was measured in the incrementally sectioned dentine collagen. Isotopic profiles for each individual included death during tooth development.

RESULTS

Individuals with skeletal evidence of chronic pathological conditions (e.g., rickets, tuberculosis) exhibited raised δ¹⁵N values of 0.5-1.7‰ in the months prior to death. Isotopic change consistent with chronic physiological stress prior to death was also recorded in two individuals with no skeletal evidence of disease. An offset was observed between co-forming bone and dentine δ¹⁵N values in both populations, indicating that bone and dentine are not recording the same isotopic changes.

CONCLUSIONS

Isotopic change consistent with chronic physiological stress was observed in both those with and without skeletal evidence of disease, suggesting that adaptation to chronic stress in childhood was not uncommon within these 19th century London populations.

SIGNIFICANCE

Chronic physiological stress prior to death may be seen in the incrementally sampled dentine of non-adults who die during tooth formation.

LIMITATIONS

The temporal resolution of current dentine micro-sampling methods may mask or minimise visibility of shorter-term periods of stress or dietary change.

SUGGESTIONS FOR FURTHER RESEARCH

Future research should further explore the relationship between specific skeletal pathologies and isotopic evidence for stress.

The "weanling's dilemma" revisited: Evolving bodies of evidence and the problem of infant paleodietary interpretation

Breastfeeding is known to be a powerful mediator of maternal and childhood health, with impacts throughout the life course. Paleodietary studies of the past 30 years have accordingly taken an enduring interest in the health and diet of young children as a potential indicator of population fertility, subsistence, and mortality patterns. While progress has been made in recent decades toward acknowledging the agency of children, many paleodietary reconstructions have failed to incorporate developments in cognate disciplines revealing synergistic dynamics between maternal and offspring biology. Paleodietary interpretation has relied heavily on the "weanling's dilemma," in which infants are thought to face a bleak choice between loss of immunity or malnutrition. Using a review of immunological and epidemiological evidence for the dynamic and supportive role that breastfeeding plays throughout the complementary feeding period, this article offers context and nuance for understanding past feeding transitions. We suggest that future interpretative frameworks for infant paleodietary and bioarchaeological research should include a broad knowledge base that keeps pace with relevant developments outside of those disciplines.

Scottish soldiers from the Battle of Dunbar 1650: A prosopographical approach to a skeletal assemblage

After the Battle Dunbar between English and Scottish forces in 1650, captured Scottish soldiers were imprisoned in Durham and many hundreds died there within a few weeks. The partial skeletal remains of 28 of these men were discovered in 2013. Building on previous osteological work, here we report wide-ranging scientific studies of the remains to address the following questions: Did they have comparable diet, health and disease throughout their lives? Did they have common histories of movement (or lack of movement) during their childhoods? Can we create a collective biography of these men? Strontium and oxygen isotope analysis of tooth enamel investigated childhood movement. Carbon and nitrogen isotope analysis of incrementally sampled dentine addressed childhood diet and nutrition. Metaproteomic analysis of dental calculus investigated oral microbiomes and food residues; this was complemented by microscopic analysis of debris in calculus from ingested materials. Selected individuals were examined for dental microwear. The extent of hydroxylation of proline in collagen was examined as a potential biomarker for scurvy. An osteobiography for each man was created using the full range of data generated about him, and these were synthesised using an approach based on the historical method for a collective biography or prosopography. The childhood residences of the men were primarily within the Midland Valley of Scotland, though some spent parts of their childhood outside the British Isles. This is concordant with the known recruitment areas of the Scottish army in 1650. Their diets included oats, brassicas and milk but little seafood, as expected for lowland rather than highland diets of the period. Childhood periods of starvation or illness were almost ubiquitous, but not simultaneous, suggesting regionally variable food shortages in the 1620s and 1630s. It is likely there was widespread low-level scurvy, ameliorating in later years of life, which suggests historically unrecorded shortages of fruit and vegetables in the early 1640s. Almost all men were exposed to burnt plant matter, probably as inhaled soot, and this may relate to the high proportion of them with of sinusitis. Interpersonal violence causing skeletal trauma was rare. Based on commonalities in their osteobiographies, we argue that these men were drawn from the same stratum of society. This study is perhaps the most extensive to date of individuals from 17^th century Scotland. Combined with a precise historical context it allows the lives of these men to be investigated and compared to the historical record with unprecedented precision. It illustrates the power of archaeological science methods to confirm, challenge and complement historical evidence.

Assessment of nutritional stress in famine burials using stable isotope analysis

OBJECTIVES

We compared δ¹⁵ N and δ¹³ C values from bone and dentine collagen profiles of individuals interred in famine-related and attritional burials to evaluate whether individuals in medieval London who experienced nutritional stress exhibit enriched nitrogen in bone and tooth tissue. Dentine profiles were evaluated to identify patterns that may be indicative of famine during childhood and were compared with the age of enamel hypoplasia (EH) formation to assess whether isotopic patterns of undernutrition coincide with the timing of physiological stress.

MATERIALS AND METHODS

δ¹⁵ N and δ¹³ C isotope ratios of bone collagen were obtained from individuals (n = 128) interred in attritional and famine burials from a medieval London cemetery (c. 1120-1539). Temporal sequences of δ¹⁵ N and δ¹³ C isotope profiles for incrementally forming dentine collagen were obtained from a subset of these individuals (n = 21).

RESULTS

Results indicate that individuals from attritional graves exhibit significantly higher δ¹⁵ N values but no significant differences were found between burial types for the sexes. Analyses of dentine profiles reveal that a lower proportion of famine burials exhibit stable dentine profiles and that several exhibit a pattern of opposing covariance between δ¹⁵ N and δ¹³ C. EH were also observed to have formed during or after the opposing covariance pattern for some individuals.

CONCLUSIONS

The results of this study may reflect differences in diet between burial types rather than nutritional stress. Though nutritional stress could not be definitively identified using bone and dentine collagen, the results from dentine analysis support previous observations of biochemical patterns associated with nutritional stress during childhood.

Sensationalism and speaking to the public: Scientific rigour and interdisciplinary collaborations in palaeopathology

OBJECTIVES

In this brief communication we discuss issues concerning scientific rigour in palaeopathological publications, particularly studies published in clinical or general science journals, that employ skeletal analysis to elucidate the lives and deaths of historical figures or interpret "mysterious" assemblages or burials. We highlight the relationship between poor methodological rigour and lack of interdisciplinary communication, and discuss how this can result in scientifically weak, sensational narratives being presented to the public.

CONCLUSIONS

Although most high profile publications involving analysis of archaeological human remains are methodologically sound and well interpreted, others have suffered from poor scientific rigour stemming from an apparent lack of awareness of anthropological methods and ethics. When these publications are highlighted by the press, sensationalistic narratives are perpetuated which may reflect poorly on our discipline and give the public unrealistic expectations about our work.

SUGGESTIONS FOR FUTURE RESEARCH

We suggest that best practice in high-profile paleopathological research include recruitment of a range of authors and reviewers from clinical sciences, anthropology, and the humanities, consideration of the ethical issues surrounding retrospective diagnosis, and transparency with the press in regards to the limitations inherent in this kind of work.

A new method for investigating the relationship between diet and mortality: hazard analysis using dietary isotopes

Background: The population of Roman Britain are renowned for having elevated nitrogen (δ¹⁵) stable isotope values, which have been interpreted as evidence for the increased consumption of marine products. However, such results are now understood to also reflect episodes of stress and disease, suggesting that new interpretations are warranted.Aim: To test a novel approach which combines hazard mortality analysis and stable isotope data to determine whether there is a relationship between age-at-death, elevated δ¹⁵N values and mortality risk.Subjects and methods: This study used published osteological and dietary stable isotope data for nitrogen (δ¹⁵N) and carbon (δ¹³C) of 659 1st-5th century AD individuals aged >12 years old excavated from Roman cemeteries in Britain. The relationship between diet and mortality risk was assessed using the Gompertz hazard model, and differences in median reported isotope values between the sexes was determined using a Mann Whitney test.Results: It was discovered that higher δ¹⁵N levels are associated with elevated risks of mortality, whereas the opposite pattern was observed for δ¹³C, and males had higher median δ¹³C and δ¹⁵N values.Conclusion: This study successfully demonstrated that stable isotope data can be integrated into hazard models, allowing one to connect diet and mortality in past populations. It supports the findings of other isotope studies which have established that individuals with childhood stress/trauma will have different isotope patterns.

Voxel-based identification of local recurrence sub-regions from pre-treatment PET/CT for locally advanced head and neck cancers

Background

Overall, 40% of patients with a locally advanced head and neck cancer (LAHNC) treated by chemoradiotherapy (CRT) present local recurrence within 2 years after the treatment. The aims of this study were to characterize voxel-wise the sub-regions where tumor recurrence appear and to predict their location from pre-treatment ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) images.

Materials and methods

Twenty-six patients with local failure after treatment were included in this study. Local recurrence volume was identified by co-registering pre-treatment and recurrent PET/CT images using a customized rigid registration algorithm. A large set of voxel-wise features were extracted from pre-treatment PET to train a random forest model allowing to predict local recurrence at the voxel level.

Results

Out of 26 expert-assessed registrations, 15 provided enough accuracy to identify recurrence volumes and were included for further analysis. Recurrence volume represented on average 23% of the initial tumor volume. The MTV with a threshold of 50% of SUVmax plus a 3D margin of 10 mm covered on average 89.8% of the recurrence and 96.9% of the initial tumor. SUV and MTV alone were not sufficient to identify the area of recurrence. Using a random forest model, 15 parameters, combining radiomics and spatial location, were identified, allowing to predict the recurrence sub-regions with a median area under the receiver operating curve of 0.71 (range 0.14–0.91).

Conclusion

As opposed to regional comparisons which do not bring enough evidence for accurate prediction of recurrence volume, a voxel-wise analysis of FDG-uptake features suggested a potential to predict recurrence with enough accuracy to consider tailoring CRT by dose escalation within likely radioresistant regions.

Multi T1-weighted contrast MRI with fluid and white matter suppression at 1.5 T

INTRODUCTION

The fluid and white matter suppression sequence (FLAWS) provides two T1-weighted co-registered datasets: a white matter (WM) suppressed contrast (FLAWS1) and a cerebrospinal fluid (CSF) suppressed contrast (FLAWS2). FLAWS has the potential to improve the contrast of the subcortical brain regions that are important for Deep Brain Stimulation surgery planning. However, to date FLAWS has not been optimized for 1.5 T. In this study, the FLAWS sequence was optimized for use at 1.5 T. In addition, the contrast-enhancement properties of FLAWS image combinations were investigated using two voxel-wise FLAWS combined images: the division (FLAWS-div) and the high contrast (FLAWS-hc) image.

METHODS

FLAWS sequence parameters were optimized for 1.5 T imaging using an approach based on the use of a profit function under constraints for brain tissue signal and contrast maximization. MR experiments were performed on eleven healthy volunteers (age 18-30). Contrast (CN) and contrast to noise ratio (CNR) between brain tissues were measured in each volunteer. Furthermore, a qualitative assessment was performed to ensure that the separation between the internal globus pallidus (GPi) and the external globus pallidus (GPe) is identifiable in FLAWS1.

RESULTS

The optimized set of sequence parameters for FLAWS at 1.5 T provided contrasts similar to those obtained in a previous study at 3 T. The separation between the GPi and the GPe was clearly identified in FLAWS1. The CN of FLAWS-hc was higher than that of FLAWS1 and FLAWS2, but was not different from the CN of FLAWS-div. The CNR of FLAWS-hc was higher than that of FLAWS-div.

CONCLUSION

Both qualitative and quantitative assessments validated the optimization of the FLAWS sequence at 1.5 T. Quantitative assessments also showed that FLAWS-hc provides an enhanced contrast compared to FLAWS1 and FLAWS2, with a higher CNR than FLAWS-div.

Comparing apples and oranges: Why infant bone collagen may not reflect dietary intake in the same way as dentine collagen

OBJECTIVES

Recent developments in incremental dentine analysis allowing increased temporal resolution for tissues formed during the first 1,000 days of life have cast doubt on the veracity of weaning studies using bone collagen carbon (δ13 C) and nitrogen (δ15 N) isotope ratio data from infants. Here, we compare published bone data from the well-preserved Anglo-Saxon site of Raunds Furnells, England, with co-forming dentine from the same individuals, and investigate the relationship of these with juvenile stature. The high-resolution isotope data recorded in dentine allow us to investigate the relationship of diet with juvenile stature during this critical period of life.

MATERIALS AND METHODS

We compare incremental dentine collagen δ13 C and δ15 N data to published bone collagen data for 18 juveniles and 5 female adults from Anglo Saxon Raunds Furnells alongside new data for juvenile skeletal and dental age. An improvement in the method by sampling the first 0.5 mm of the sub-cuspal or sub-incisal dentine allows the isotopic measurement of dentine formed in utero.

RESULTS AND DISCUSSION

δ13 C profiles for both dentine and bone are similar and more robust than δ15 N for estimating the age at which weaning foods are introduced. Our results suggest δ15 N values from dentine can be used to evaluate the maternal/in utero diet and physiology during pregnancy, and that infant dentine profiles may reflect diet PLUS an element of physiological stress. In particular, bone collagen fails to record the same range of δ15 N as co-forming dentine, especially where growth is stunted, suggesting that infant bone collagen is unreliable for weaning studies.

Crystallographic texture and mineral concentration quantification of developing and mature human incisal enamel

For human dental enamel, what is the precise mineralization progression spatially and the precise timing of mineralization? This is an important question in the fundamental understanding of matrix-mediated biomineralization events, but in particular because we can use our understanding of this natural tissue growth in humans to develop biomimetic approaches to repair and replace lost enamel tissue. It is important to understand human tissues in particular since different species have quite distinct spatial and temporal progression of mineralization. In this study, five human central incisors at different stages of enamel maturation/mineralization were spatially mapped using synchrotron X-ray diffraction and X-ray microtomography techniques. From the earliest developmental stage, two crystallite-orientation populations coexist with angular separations between the crystallite populations of approximately 40° varying as a function of position within the tooth crown. In general, one population had significantly lower texture magnitude and contributed a higher percentage to the overall crystalline structure, compared to the other population which contributed only 20-30% but had significantly higher texture magnitude. This quantitative analysis allows us to understand the complex and co-operative structure-function relationship between two populations of crystallites within human enamel. There was an increase in the mineral concentration from the enamel-dentin junction peripherally and from the incisal tip cervically as a function of maturation time. Quantitative backscattered-electron analyses showed that mineralization of prism cores precedes that of prism boundaries. These results provide new insights into the precise understanding of the natural growth of human enamel.

The role of infant life histories in the construction of identities in death: An incremental isotope study of dietary and physiological status among children afforded differential burial

OBJECTIVES

Isotope ratio analyses of dentine collagen were used to characterize short-term changes in physiological status (both dietary status and biological stress) across the life course of children afforded special funerary treatment.

MATERIALS AND METHODS

Temporal sequences of δ¹⁵ N and δ¹³ C isotope profiles for incrementally forming dentine collagen were obtained from deciduous teeth of 86 children from four early-medieval English cemeteries. Thirty-one were interred in child-specific burial clusters, and the remainder alongside adults in other areas of the cemetery. Isotope profiles were categorized into four distinct patterns of dietary and health status between the final prenatal months and death.

RESULTS

Isotope profiles from individuals from the burial clusters were significantly less likely to reflect weaning curves, suggesting distinctive breastfeeding and weaning experiences. This relationship was not simply a factor of differential age at death between cohorts. There was no association of burial location neither with stage of weaning at death, nor with isotopic evidence of physiological stress at the end of life.

DISCUSSION

This study is the first to identify a relationship between the extent of breastfeeding and the provision of child-specific funerary rites. Limited breastfeeding may indicate the mother had died during or soon after birth, or that either mother or child was unable to feed due to illness. Children who were not breastfed will have experienced a significantly higher risk of malnutrition, undernutrition and infection. These sickly and perhaps motherless children received care to nourish them during early life, and were similarly provided with special treatment in death.

An unusual exostotic lesion of the maxillary sinus from Roman Lincoln

This report provides a differential diagnosis of an exostotic bony lesion within the left maxillary sinus of a Romano-British (3rd to 4th century AD) adult male from Newport, Lincoln. Macroscopic, radiographic, and cone beam computed tomography (CBCT) analyses suggest that the lesion is likely of odontogenic origin. The overall size of the lesion and areas of sclerosis and radiolucency, together with its hypothesised odontogenic origin, suggest that the lesion represents a chronic exostotic osteomyelitic reaction to the presence of odontogenic bacteria. While modern case studies of odontogenic maxillary sinus osteomyelitis are noteworthy, published cases of this condition are extremely rare in an archaeological context and may be underreported due to the enclosed nature of the sinuses. Such infections may have serious implications for individual and population health, and non-destructive investigation should be considered in cases where significant maxillary caries are present.

Infant mortality and isotopic complexity: New approaches to stress, maternal health, and weaning

OBJECTIVES

Studies of the carbon and nitrogen stable isotope ratios (δ(13) C and δ(15) N) of modern tissues with a fast turnover, such as hair and fingernails, have established the relationship between these values in mothers and their infants during breastfeeding and weaning. Using collagen from high-resolution dentine sections of teeth, which form in the perinatal period we investigate the relationship between diet and physiology in this pivotal stage of life.

MATERIALS AND METHODS

Childhood dentine collagen δ(13) C and δ(15) N profiles were produced from horizontal sections of permanent and deciduous teeth following the direction of development. These were from two 19th-century sites (n = 24) and a small number (n = 5) of prehistoric samples from Great Britain and Ireland.

RESULTS

These high-resolution data exhibit marked differences between those who survived childhood and those who did not, the former varying little and the latter fluctuating widely.

DISCUSSION

Breastfeeding and weaning behavior have a significant impact on the morbidity and mortality of infants and the adults they become. In the absence of documentary evidence, archaeological studies of bone collagen of adults and juveniles have been used to infer the prevalence and duration of breastfeeding. These interpretations rely on certain assumptions about the relationship between isotope ratios in the bone collagen of the adult females and the infants who have died. The data from this study suggest a more complex situation than previously proposed and the potential for a new approach to the study of maternal and infant health in past populations.

Mapping the spatial and temporal progression of human dental enamel biomineralization using synchrotron X-ray diffraction

OBJECTIVE

The complex biological, physicochemical process of human dental enamel formation begins in utero and for most teeth takes several years to complete. Lost enamel tissue cannot regenerate, therefore a better understanding of the spatial and temporal progression of mineralization of this tissue is needed in order to design improved in vivo mineral growth processes for regenerative dentistry and allow the possibility to grow a synthetic whole or partial tooth.

METHOD

Human dental enamel samples across a range of developmental stages available through archaeological collections have been used to explore the spatial and temporal progression of enamel biomineralization. Position sensitive synchrotron X-ray diffraction was used to quantify spatial and temporal variations in crystallite organization, lattice parameters and crystallite thickness at three different stages in enamel maturation. In addition X-ray microtomography was used to study mineral content distributions.

RESULTS

An inverse correlation was found between the spatial variation in mineral content and the distribution of crystallite organization and thickness as a function of time during enamel maturation. Combined X-ray microtomography and synchrotron X-ray diffraction results show that as enamel matures the mineral content increases and the mineral density distribution becomes more homogeneous. Starting concurrently but proceeding at a slower rate, the enamel crystallites become more oriented and larger; and the crystallite organization becomes spatially more complex and heterogeneous.

CONCLUSION

During the mineralization of human dental enamel, the rate of mineral formation and mineral organization are not identical. Whilst the processes start simultaneously, full mineral content is achieved earlier, and crystallite organization is slower and continues for longer. These findings provide detailed insights into mineral development in human dental enamel which can inform synthetic biomimetic approaches for the benefit of clinical dentistry.

Patient-reported outcomes in a randomized trial of everolimus with metastatic renal cell carcinoma patients

e17516

Background: Patient-reported outcomes (PRO), including health-related quality of life (HRQL), were assessed in a Phase III trial of everolimus in metastatic renal cell carcinoma (mRCC) patients. Methods: Patients with mRCC were randomized (n=416) to receive everolimus or placebo plus best supportive care. Patients completed the FACT-Kidney Symptom Index- Disease Related Symptoms (FKSI-DRS) and EORTC-QLQ C30 at baseline and monthly during treatment. Karnofsky Performance Status (KPS) was also assessed at baseline and monthly during treatment. Primary analyses included time to deterioration defined as a decrease from baseline of at least 3 points for FKSI-DRS, at least 10% for EORTC Physical Function (PF) and Global Quality of Life (QL) scales, and at least 10 points for KPS. Secondary analyses considered tumor progressions that occurred prior to deterioration or censoring date as FKSI deterioration events and compared time to PRO deterioration by tumor progression. Comparisons were made using stratified log-rank tests and Cox proportional hazard models. Results: Time to deterioration in KPS was longer in the everolimus arm, and time to deterioration in FKSI-DRS was slightly longer ( Table ). There was no difference in time to deterioration in PF or QL. Secondary analyses showed median time to deterioration in FKSI-DRS was approximately doubled for the everolimus arm compared to placebo, and patients who progressed experienced a more rapid deterioration in FKSI-DRS and QL scores. Conclusions: Compared to placebo everolimus delayed progression of disease-related symptoms and KPS. No effect on time to deterioration of PF or QL could be determined. Secondary analyses suggest a delay in deterioration in kidney cancer related symptoms via tumor control.

[Table: see text]

[Table: see text]

Patient-centered validation of 11 symptom indices to evaluate response to chemotherapy for advanced cancer

6524

Background: Symptom burden in advanced disease has relevance both for clinical practice and in evaluating the efficacy of new chemotherapeutic agents. This study aimed to identify patients’ highest priority symptoms for 11 advanced cancers, compare priority ratings with those obtained from clinicians, and construct brief symptom indices based on their combined input. Methods: 534 patients with advanced bladder, brain, breast, colorectal, head/neck, hepatobiliary/pancreatic, kidney, lung, lymphoma, ovarian or prostate cancer from a subset of National Comprehensive Cancer Network (NCCN) member institutions and 4 Cancer Health Alliance of Metropolitan Chicago organizations completed a survey of priority symptoms and concerns and a disease-specific FACT QOL measure. 112 physicians at NCCN institutions completed a rating of whether symptoms and concerns were considered disease- or treatment-related. Symptoms endorsed more often than chance probability were retained. Expert clinician and patient ratings were equally weighted in item selection. Responses to symptom index items drawn from the QOL questionnaires allowed for validation analyses. Results: Items comprising 2 to 3 subscales (up to 20 items in length) were retained for each of the 11 disease-specific symptom indices. Content-determined subscales consisted of symptoms and concerns that were 1) exclusively or predominantly disease-related symptoms (DRS); 2) exclusively or predominantly treatment side effects (TSE); and 3) descriptive of general function or well-being (F/WB). For example, the NCCN/FACT Breast Cancer Symptom Index (FBSI) contains 17 items: 8 DRS, 4 TSE and 5 F/WB. Data on 14 of 17 FBSI items showed good internal consistency (a=.89). Correlations between FBSI and FACT-B scores were high for physical well-being, functional well-being and breast cancer subscales (r = 0.83, 0.77, and 0.61 respectively). Correlation with emotional well-being subscale was 0.55. FBSI scores differed across PSR groups in the appropriate direction (p<0.0001). Conclusions: NCCN/FACT disease-specific questionnaires have been transformed into brief, patient-centered symptom indices that can be used as stand-alone measures in oncology research and practice.

No significant financial relationships to disclose.

Validation of the Functional Assessment of Cancer Therapy-Ovarian (FACT-O) Symptom Index (FOSI) in a phase II clinical trial of pertuzumab in patients with advanced ovarian cancer

16021

Background: The FOSI is a very brief(8-item) index derived from the FACT-O to measure symptom response to treatment for ovarian cancer(OC). We evaluated its performance in a single arm Phase II clinical trial. Methods: The FOSI was administered to patients with advanced OC participating in a single arm Ph II clinical trial of pertuzumab(Gordon et al, JCO (2006) v24:4324;2006)). Pertuzumab, a humanized HER2 antibody is the first in a new class of investigational agents known as HER dimerization inhibitors(HDIs). Patients completed the FOSI at D1 of each 3 week cycle, up to 17 cycles. Validation analyses focused on data from the first 4 cycles and included Cronbach's alpha coefficients plus cross-sectional and longitudinal comparisons of groups defined by ECOG performance status (PS). Results: 62 patients completed the FOSI at baseline (B), 54 at cycle 2, 44 at cycle 3 and 27 at cycle 4. The FOSI showed acceptable internal consistency reliability with alphas of 0.73 to 0.80. The FOSI differentiated patients with PS 0 from those with PS =1 at each cycle (Table). There was a difference in FOSI scores in patients with worsened PS from those whose PS improved or was unchanged at cycle 2 only (p<0.001). The ES (mean change/ SD of change scores) for the group with worsened PS was -0.77. The minimally important difference was estimated to be 2–3 points. Conclusions: The FOSI is a valid symptom measure in this population of OC patients, demonstrating acceptable reliability, validity and responsiveness to clinical change. [Table: see text]

No significant financial relationships to disclose.

Trajectory of cognitive impairment during breast cancer treatment: A prospective analysis

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Background: Several studies havedocumented cognitive impairment in cancer patients; however these reports are primarily based on cross-sectional comparisons. Prospective evaluation would better elucidate the onset and course of cognitive dysfunction related to chemotherapy. Methods: Of 72 breast cancer patients enrolled, 51 completed a comprehensive neuropsychological battery before chemotherapy (T1), on Day 1 of Cycle 4 (T2), and at 6-month follow-up (T3). Participants scoring ≥ 1 SD below the normative mean on ≥ 3 neuropsychological tests OR ≥ 2 SD below on 1 test were classified as impaired. Reliable change indices (RCI) conservatively estimated significant change over time. Results: Participants were White (70.6%) females (96.1%) with a mean of 15.9 ± 2.3 years of education. Mean age was 51.6 ± 8.6 years and most had Stage II (78%) or Stage III (16%) disease. Hospital Anxiety and Depression Scale scores were in the normal range at all assessments and were unrelated to T1 cognitive impairment. Consistent with previous research, 9 (17.6%) of patients met criteria for cognitive impairment at T1. By T2, 14 (27.4%) were cognitively impaired; however, at T3 follow up only 5 (9.8%) were impaired. As noted in the table, most impairment occurs during chemotherapy. Among patients not impaired before chemotherapy it was uncommon for impairment at T2 to persist at follow-up. Conclusions: Some breast cancer patients indeed develop cognitive impairment during treatment, much of which appears to resolve at 6 months. Domains most affected include attention, visuospatial skills, and working memory. Attention problems resolved by 6 months, while working memory and visuospatial deficits persisted.

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No significant financial relationships to disclose.

A randomized phase II trial comparing every 3-weeks carboplatin/paclitaxel with every 3-weeks carboplatin and weekly paclitaxel in advanced non-small cell lung cancer

BACKGROUND

The optimal schedule of taxane administration has been an area of active interest in several recent clinical trials.

METHODS

To address a pure schedule question, we randomized 161 patients with advanced stage IIIB or IV non-small-cell lung cancer (NSCLC) to either paclitaxel 225 mg/m2 every 3 weeks x 4 cycles or 75 mg/m2/week x 12 (cumulative dose on each arm = 900 mg/m2). Both arms received concurrent carboplatin AUC 6 every 3 weeks x 4 cycles.

RESULTS

The two arms were well-balanced in terms of known prognostic factors. The overall response rate and survival outcomes were similar on the two arms. There was significantly more grade 3/4 thrombocytopenia and grade 2-4 anemia on the weekly arm but less severe myalgias/arthralgias and alopecia. No difference in the rates of peripheral neuropathy was observed; however, patients on the every 3 weeks arm reported significantly more taxane therapy-related side-effects on the functional assessment of cancer therapy taxane subscale.

CONCLUSIONS

This randomized trial exploring schedule-related issues with carboplatin/paclitaxel confirms the versatility of this regimen.

Rectification of the background potassium current: a determinant of rotor dynamics in ventricular fibrillation

Ventricular fibrillation (VF) is the leading cause of sudden cardiac death. Yet, the mechanisms of VF remain elusive. Pixel-by-pixel spectral analysis of optical signals was carried out in video imaging experiments using a potentiometric dye in the Langendorff-perfused guinea pig heart. Dominant frequencies (peak with maximal power) were distributed throughout the ventricles in clearly demarcated domains. The fastest domain (25 to 32 Hz) was always on the anterior left ventricular (LV) wall and was shown to result from persistent rotor activity. Intermittent block and breakage of wavefronts at specific locations in the periphery of such rotors were responsible for the domain organization. Patch-clamping of ventricular myocytes from the LV and the right ventricle (RV) demonstrated an LV-to-RV drop in the amplitude of the outward component of the background rectifier current (I(B)). Computer simulations suggested that rotor stability in LV resulted from relatively small rectification of I(B) (presumably I(K1)), whereas instability, termination, and wavebreaks in RV were a consequence of strong rectification. This study provides new evidence in the isolated guinea pig heart that a persistent high-frequency rotor in the LV maintains VF, and that spatially distributed gradients in I(K1) density represent a robust ionic mechanism for rotor stabilization and wavefront fragmentation.