Ice volume and climate changes from a 6000 year sea-level record in French Polynesia.

Mid- to late-Holocene sea-level records from low-latitude regions serve as an important baseline of natural variability in sea level and global ice volume prior to the Anthropocene. Here, we reconstruct a high-resolution sea-level curve encompassing the last 6000 years based on a comprehensive study of coral microatolls, which are sensitive low-tide recorders. Our curve is based on microatolls from several islands in a single region and comprises a total of 82 sea-level index points. Assuming thermosteric contributions are negligible on millennial time scales, our results constrain global ice melting to be 1.5-2.5 m (sea-level equivalent) since ~5500 years before present. The reconstructed curve includes isolated rapid events of several decimetres within a few centuries, one of which is most likely related to loss from the Antarctic ice sheet mass around 5000 years before present. In contrast, the occurrence of large and flat microatolls indicates periods of significant sea-level stability lasting up to ~300 years.

SEA-LEVEL RISE. Sea-level rise due to polar ice-sheet mass loss during past warm periods.

Interdisciplinary studies of geologic archives have ushered in a new era of deciphering magnitudes, rates, and sources of sea-level rise from polar ice-sheet loss during past warm periods. Accounting for glacial isostatic processes helps to reconcile spatial variability in peak sea level during marine isotope stages 5e and 11, when the global mean reached 6 to 9 meters and 6 to 13 meters higher than present, respectively. Dynamic topography introduces large uncertainties on longer time scales, precluding robust sea-level estimates for intervals such as the Pliocene. Present climate is warming to a level associated with significant polar ice-sheet loss in the past. Here, we outline advances and challenges involved in constraining ice-sheet sensitivity to climate change with use of paleo-sea level records.

Modelling the glacial isostatic adjustment of the UK region.

The glacial isostatic adjustment of the UK region has been considered in a number of recent studies. We have revisited this problem in order to: (i) highlight some key issues with regard to limitations in the ice modelling approach adopted in these studies and (ii) consider the constraints provided from observations of crustal motion available via continuous global positioning system monitoring. With regard to the first aim, we have found that: (i) previous studies have significantly overestimated ice thicknesses in regions where trim line field constraints were adopted and (ii) the duration of the glaciation phase of the UK ice sheet is a critical aspect of the model and that discrepancies in this model component have led to inconsistent inferences of Earth model parameters. With regard to the second aim, we have found that predictions of horizontal velocities (relative to a chosen site) based on a UK ice model calibrated to fit the regional sea-level database capture the geometry of the signal well but only account for 10% of the magnitude (for a range of Earth models).

Sea-level fingerprinting as a direct test for the source of global meltwater pulse IA.

The ice reservoir that served as the source for the meltwater pulse IA remains enigmatic and controversial. We show that each of the melting scenarios that have been proposed for the event produces a distinct variation, or fingerprint, in the global distribution of meltwater. We compare sea-level fingerprints associated with various melting scenarios to existing sea-level records from Barbados and the Sunda Shelf and conclude that the southern Laurentide Ice Sheet could not have been the sole source of the meltwater pulse, whereas a substantial contribution from the Antarctic Ice Sheet is consistent with these records.

Space-geodetic constraints on glacial isostatic adjustment in Fennoscandia.

Analysis of Global Positioning System (GPS) data demonstrates that ongoing three-dimensional crustal deformation in Fennoscandia is dominated by glacial isostatic adjustment. Our comparison of these GPS observations with numerical predictions yields an Earth model that satisfies independent geologic constraints and bounds both the average viscosity in the upper mantle (5 x 10(20) to 1 x 10(21) pascal seconds) and the elastic thickness of the lithosphere (90 to 170 kilometers). We combined GPS-derived radial motions with Fennoscandian tide gauge records to estimate a regional sea surface rise of 2.1 +/- 0.3 mm/year. Furthermore, ongoing horizontal tectonic motions greater than approximately 1 mm/year are ruled out on the basis of the GPS-derived three-dimensional crustal velocity field.

Recent mass balance of polar ice sheets inferred from patterns of global sea-level change.

Global sea level is an indicator of climate change, as it is sensitive to both thermal expansion of the oceans and a reduction of land-based glaciers. Global sea-level rise has been estimated by correcting observations from tide gauges for glacial isostatic adjustment--the continuing sea-level response due to melting of Late Pleistocene ice--and by computing the global mean of these residual trends. In such analyses, spatial patterns of sea-level rise are assumed to be signals that will average out over geographically distributed tide-gauge data. But a long history of modelling studies has demonstrated that non-uniform--that is, non-eustatic--sea-level redistributions can be produced by variations in the volume of the polar ice sheets. Here we present numerical predictions of gravitationally consistent patterns of sea-level change following variations in either the Antarctic or Greenland ice sheets or the melting of a suite of small mountain glaciers. These predictions are characterized by geometrically distinct patterns that reconcile spatial variations in previously published sea-level records. Under the--albeit coarse--assumption of a globally uniform thermal expansion of the oceans, our approach suggests melting of the Greenland ice complex over the last century equivalent to -0.6 mm yr(-1) of sea-level rise.

An all age group study of the prevalence of asthma in Golden Bay.

AIMS: To determine the prevalence of asthma within the total population of a region defined by census and geographical boundaries. METHODS: Patients on the asthma register of the sole medical centre in the region of Golden Bay, during the period of six months before the March 1991 census, were compared by age and sex with the census figures for the whole population. The methods of verifying the numbers on the register are described. RESULTS: The total number of patients of all age groups under treatment for asthma was 260, giving a prevalence of asthma in the population of 4803 of 5.41% (males 5.67%, females 5.11%). In children between ages 1-14 years there were 9.21% with asthma. The prevalence, defined by percentage for each group, rises from infancy to peak in the mid teens at 10%, followed by a steady decline to the mid thirties to 3.4%, and thereafter a rather flat plateau between 3.5% and 4% into old age. CONCLUSIONS: Previous studies of the prevalence of asthma have been limited to schoolchildren. Whole population studies, within a defined region, are likely to offer more information for the planning of healthcare resources, and may give some clues to understanding the natural history of the disease.

Membranous expression of carcinoembryonic antigen (CEA) in the normal cervical squamous mucosa.

Using a panel of polyclonal and monoclonal antibodies to CEA-related antigens in paraffin-processed cervical biopsies, CEA and NCA expression has been demonstrated on the cell membrane of normal mature cervical squames. Cytofluorimetry of disaggregated cervical squames confirmed membranous expression and immunogold labelling of ultrathin cryostat sections localized CEA to the glycocalyx and to within cytoplasmic membrane-bound vesicles of mature squames. Immunoblotting of cervical tissue showed that most of the CEA reactivity was expressed as a glycoprotein of molecular weight around 180 k, probably CEA itself. Localization of the CEA to the cell membrane of mature cervical squames suggests a key role for these antigens in maintaining the integrity of the squamous mucosa, through the putative function of an adhesion molecule.

Expression of the 3-fucosyl N-acetyllactosamine (CD 15) antigen in normal, metaplastic, dysplastic, and neoplastic squamous epithelia.

The 3-fucosyl N-acetyllactosamine residue is the antigen recognized by the monoclonal antibody MC2. Using MC2, we demonstrated the distribution of this antigen in a variety of squamous epithelia. The antigen is expressed to a variable degree on supra-basal cells in most normal non-keratinizing squamous mucosae, with a similar distribution in metaplastic squamous epithelia; antibody-labelled latex microspheres and immunogold electron microscopy show the antigen to form part of the glycocalyx. In dysplastic and neoplastic squamous lesions, expression is reduced or absent except in cells around areas of differentiation. Prior neuraminidase treatment of sections had little effect on the amount or distribution of demonstrable antigen. Expression of this antigen by cells in non-keratinizing squamous epithelia gives an indication of cell maturity and may provide a histological marker for the grading of dysplastic and malignant squamous mucosal lesions. A possible role for these carbohydrate residues in squamous mucosal defence is discussed.

Oesophageal neoplasia in male Wistar rats due to parenteral di(2-hydroxypropyl)-Nitrosamine (DHPN): a combined histopathological, histochemical and electron microscopic study.

Intraperitoneal di(2-hydroxypropyl)-Nitrosamine (DHPN) caused a high incidence of oesophageal squamous carcinoma in male Wistar rats, particularly in rats killed 11 or more months after the start of injections. No control rats (injected intraperitoneally with saline) developed an oesophageal neoplasms. Histopathologically, the tumours were moderately well differentiated. Histochemical studies showed minor increases in mucin staining and mast cell population and a marked increase in bacteria in tumour-bearing oesophaguses. Electron microscopy showed the tumours to be similar to, but to differ in some respects from squamous carcinomas at other sites in humans. The possible implications of this work for human disease are twofold. It could provide a model for further study of aspects of oesophageal carcinoma and it serves to remind us that all potential oesophageal carcinogens need not act during swallowing.

Chronic subphrenic abscess: the missed diagnosis.

This report of a case of chronic subphrenic abscess, with a brief review and recommendations for diagnosis and prevention, draws attention to this clinical entity as a potential cause of chronic ill health. The clinical presentation and laboratory findings in this case were unremarkable. It is clear that the condition can be easily missed and the patient may be exposed unnecessarily to prolonged illness and to inappropriate investigation and therapy.