Metformin treatment of diverse Caenorhabditis species reveals the importance of genetic background in longevity and healthspan extension outcomes

Metformin, the most commonly prescribed anti‐diabetes medication, has multiple reported health benefits, including lowering the risks of cardiovascular disease and cancer, improving cognitive function with age, extending survival in diabetic patients, and, in several animal models, promoting youthful physiology and lifespan. Due to its longevity and health effects, metformin is now the focus of the first proposed clinical trial of an anti‐aging drug—the Targeting Aging with Metformin (TAME) program. Genetic variation will likely influence outcomes when studying metformin health effects in human populations. To test for metformin impact in diverse genetic backgrounds, we measured lifespan and healthspan effects of metformin treatment in three Caenorhabditis species representing genetic variability greater than that between mice and humans. We show that metformin increases median survival in three C. elegans strains, but not in C. briggsae and C. tropicalis strains. In C. briggsae, metformin either has no impact on survival or decreases lifespan. In C. tropicalis, metformin decreases median survival in a dose‐dependent manner. We show that metformin prolongs the period of youthful vigor in all C. elegans strains and in two C. briggsae strains, but that metformin has a negative impact on the locomotion of C. tropicalis strains. Our data demonstrate that metformin can be a robust promoter of healthy aging across different genetic backgrounds, but that genetic variation can determine whether metformin has positive, neutral, or negative lifespan/healthspan impact. These results underscore the importance of tailoring treatment to individuals when testing for metformin health benefits in diverse human populations.

Adaptation of the adult Functional Mobility Assessment (FMA) into a FMA-Family Centred (FMA-FC) paediatric version

AIM

The aims of this study were to adapt an adult wheeled mobility outcome measure, the Functional Mobility Assessment, for use with children (FMA-Family Centred) and establish the new measure's content validity, test-retest reliability, and internal consistency.

BACKGROUND

Although several tools exist to measure a child's ability to operate and move a wheeled mobility device, none focus on the ability of the wheeled mobility device to support children and their families as they perform daily activities.

METHODS

After adapting the FMA items with examples relevant to children aged 3-21, parent/caregiver and therapist stakeholder groups recommended adaptations relevant for families with children who cannot respond for themselves.

RESULTS

Six of the initial FMA items were retained with child-appropriate examples, and 4 new items were developed.

CONCLUSION

The content validity of the FMA-Family Centred was strongly supported, and internal consistency and test-retest reliability met accepted psychometric standards.

A randomised trial of skin photography as an aid to screening skin lesions in older males

OBJECTIVES

We have previously shown that photographs assist in detection of change in skin lesions and designed the present randomised population based trial to assess the feasibility of photographs as an aid to management of skin cancers in older men.

SETTING

1899 men over fifty, identified from the electoral roll in two regions in New South Wales (NSW), Australia, were invited by mail to participate.

METHODS

A total of 973 of 1037 respondents were photographed and randomised into intervention (participants given their photographs) or control groups (photographs withheld by investigators). At one and two years from the time of photography, all participants were advised to see their primary care practitioner for a skin examination. Those in the intervention group were examined with their photographs and those in the control group without their photographs.

RESULTS

The results indicated that the practitioners were more likely to leave suspicious lesions in place for follow up observation (37% v 29%) (p=0.006) and less likely to excise benign non pigmented lesions (20 v 32%). There was little difference in excision rates for benign pigmented lesions (21% v 23%). Lesions excised were more likely to be non-melanoma skin cancer (58% v 42%) from patients who had photographs compared to those without photographs (p=0.005). The use of skin photography resulted in a substantial savings due to the reduced excision of benign lesions.

CONCLUSIONS

These results suggest that it would be feasible to conduct a large scale randomised trial to evaluate the value of photography in early detection of melanoma and that such a trial could be cost effective due to the reduced excision of benign skin lesions.

Participation of older males in a study on photography as an aid to early detection of melanoma

OBJECTIVE

To examine the acceptability of photography as an aid to skin examinations in men over 50 years of age.

METHODS

A randomised trial of men selected from the electoral roll. All participants were photographed, but only half received their photographs. Skin examinations by GPs at years one and two.

RESULTS

55% of men consented to have photographs taken and 51% did so. 86% of respondents had risk factors for melanoma (compared to 68% of non-responders) and 47% had two or more risk factors (compared to 23% of non-responders). At year one, 91% of participants remaining in study regions had been examined. Photographs were lost by only six participants.

CONCLUSIONS

Men over 50 years of age respond to personalised health messages about melanoma and respondents include a high proportion of males with risk factors for melanoma.

IMPLICATIONS

These initial results suggest that photography may be a logistically acceptable approach for assisting in the early detection of melanoma.

Research on late Pliocene Oldowan sites at Kanjera South, Kenya

The late Pliocene is notable for the appearance of two new hominid genera as well as the first archaeological sites, generally attributed to the Oldowan Industrial Complex. However, the behavioral ecology of Oldowan hominids has been little explored, particularly at sites older than 2.0 Ma. Moreover, debates on Oldowan hominid foraging ecology and behavior have centered on data from only two regions, and often from single site levels. Here we describe the preliminary results of our investigation of Oldowan occurrences at Kanjera South. These occurrences preserve the oldest known traces of hominid activity in southwestern Kenya, and unlike most of the Oldowan sites in the 2.0-2.5 Ma time interval, artefacts are found in spatial association with a well-preserved fauna. In 1996 and 1997, this project initiated the first excavation program for Kanjera South. Magneto- and biostratigraphy indicate that deposition began approximately 2.2 Ma, substantially earlier than previously thought. At Excavation 1, artefacts were found in spatial association with a taxonomically diverse faunal assemblage in Beds KS-1 and KS-2. Excavation 2 yielded a partial hippopotamus axial skeleton with artefacts in KS-3. Cores from both sites were incidentally flaked and represent a Mode I lithic technology indistinguishable from the Oldowan. Approximately 15% of the artefacts were manufactured from non-local raw materials, indicating a flow of resources into the area. Stable isotopic analysis of KS-1 and KS-2 pedogenic carbonates suggests that the Excavation 1 assemblages formed in a relatively open (>75% C4 grass) habitat. The Excavation 1 and 2 faunas contain a high proportion of equids relative to Oldowan accumulations from Bed I Olduvai Gorge, Tanzania. Beds KS-1 and KS-2 thus preserve traces of Oldowan hominid activities in a more open setting than has been previously documented.

Current research on the late Pliocene and Pleistocene deposits north of Homa Mountain, southwestern Kenya

The late Pliocene and Pleistocene sediments of the Homa Peninsula in southwestern Kenya are richly fossiliferous, preserve Early Stone Age archaeological traces and provide one of the few paleoanthropological data sets for the region between the branches of the East African Rift Valley. This paper presents preliminary results of our ongoing investigation of late Pliocene and Pleistocene deposits at the localities of Rawi, Kanam East, Kanam Central and Kanjera. While fossils have been collected from the peninsula since 1911, little systematic effort has been made to place them into a broader litho-and chronostratigraphic framework. This project has conclusively demonstrated that fossils occur in good stratigraphic context at all of the study localities and that claims of sediment slumping (Boswell, 1935) have been greatly overstated (Behrensmeyer et al., 1995; Plummer & Potts, 1989). A provisional chronostratigraphic framework based on magneto- and biostratigraphy is presented here. We have revised the Plio-Pleistocene stratigraphy of the Rawi and Kanam gullies to include three formations: the Rawi, Abundu and Kasibos Formations. Based on magneto- and biostratigraphy, these formations are dated between approximately three and one m.y.a. (Gauss Chron-Jaramillo Subchron) (Cande & Kent, 1995). The Apoko Formation unconformably overlies the others and may be middle to late Pleistocene in age. All formations contain rich patches of fossils, and Acheulean artifacts have been surface collected from the Abundu and Kasibos Formations. Deposition of the fossil- and artefact-bearing sediments at Kanjera North began in the early Pleistocene and continued into the middle Pleistocene. Deposition at Kanjera South began over one million years earlier than previously thought, at approximately 2.2 m.y.a., and continued into the Olduvai Subchron (1.770-1.950 m.y.a.; Cande & Kent, 1995). Excavations have recovered Oldowan artefacts in association with well-preserved fossil fauna near the base of the sequence, the oldest archaeological traces yet known from southwestern Kenya.

Bovids as indicators of Plio-Pleistocene paleoenvironments in east Africa

Reconstructions of the paleoenvironments of early hominids offer a framework for understanding hominid ecological and behavioral adaptations. Habitat reconstructions typically rely upon various biological or physical habitat indicators, and here we present reconstructions of the Plio-Pleistocene paleohabitats of Koobi Fora and Olduvai Gorge as based on fossil bovids (Artiodactyla: Bovidae). Bovids are the most common faunal element at most Neogene hominid and hominoid fossil localities and have been widely studied. This study addresses the functional morphology of the bovid femur through discriminant function analysis and provides additional support for the observation that certain features of the femur demonstrate clear correlations with the amount of vegetative cover in different modern habitats. The reconstructions for both Koobi Fora and Olduvai Gorge suggest that the full range of environments inhabited by living bovids was present during the Plio-Pleistocene. Koobi Fora appears to have had a somewhat higher percentage of more closed habitats than the relatively more open habitats of Olduvai Gorge. These habitat reconstructions are in broad agreement with other reconstructions based on a purely taxonomic approach to the bovid remains. Grounding our reconstructions of paleoenvironments in studies of functional morphology can help to develop a richer idea of the habitats and resources available to early hominids.

Hominid fossil sample from Kanjera, Kenya: description, provenance, and implications of new and earlier discoveries

Anatomically modern hominids were first collected from Kanjera, Kenya, by L.S.B. Leakey in the 1930s. Their apparent association with an archaic fauna was quickly challenged, throwing their age into doubt. Further unpublished hominid fragments were collected in 1974, 1975, 1981, and 1987. We review the context and morphology of the entire hominid sample. A minimum number of five individuals is represented by both cranial and postcranial elements. Several individuals have thickened cranial vaults, a characteristic originally thought to reflect their great antiquity. Vault thickening resulted from diploic expansion and may have been a response to acquired or inherited anemia. The entire hominid sample postdates the Kanjera Formation, deposited from the early into the middle Pleistocene. Most of the sample was derived from the black cotton soil capping the stratigraphic column. The morphology and context of the Kanjera hominids is consistent with human skeletal remains from nearby Holocene sites. Hominid 3 was probably an intrusive burial into an early Pleistocene bed.