bluuebunny/crossref_metadata_2025 huggingface dataset:
CAFFEINE AND OTHER XANTHINES AS CYTOCHEMICAL BLOCKERS AND REMOVERS OF HETEROCYCLIC DNA INTERCALATORS FROM CHROMATIN
Authors: Lyles Mark B. , Cameron Ivan L.
Published: October 2002

Caffeine (CAF) and other xanthines non‐covalently bind with the cationic fluorescent dye acridine orange (AO) and with other heterocyclic mutagens and carcinogens that are known to intercalate into double‐stranded DNA (dsDNA). Fluorescence microscopy and spectrofluorometry studies were employed to test the ability of caffeine and certain other methyl substituted xanthines, with different binding affinities for AO, to inhibit and to reverse the intercalation of AO and other heterocyclic agents from intercalation with the DNA of nuclear chromatin of air‐dried cells. Results indicated that xanthines with binding affinity for AO greater than 150m−1 block the AO molecule in a concentration dependent manner and comply with mass action kinetics. Thus CAF and other xanthines can be used to either inhibit intercalation of AO into nuclear DNA or to remove AO once intercalated into nuclear DNA. The interactions between other planar heterocyclics, xanthines, and nuclear chromatin dsDNA were also found to be non‐covalent. Studies are needed to determine the ability of CAF and other xanthines to block and/or remove polyaromatic hydrocarbon (PAH) intercalators from the DNA of living cells.
FK506 ENHANCED OSTEOBLASTIC DIFFERENTIATION IN MESENCHYMAL CELLS
Authors: Tang Lin , Ebara Sohei , Kawasaki Satoshi , Wakabayashi Shinji , Nikaido Toshio , Takaoka Kunio
Published: October 2002

Bone morphogenetic protein (BMP) is a bone‐derived growth factor capable of promoting the differentiation of mesenchymal cells into osteogenic lineage pathways. Recently, immunosuppressants were reported to cause a moderate increase in osteoblastic differentiation in a rat osteoblast‐like osteosarcoma cell line. If immunosuppressants can induce osteoblastic differentiation, it will be useful for bone tissue transplantation. We assessed the effect of immunosuppressants with or without BMP‐4 on inducing osteoblastic differentiation in osteoblast‐like and other mesenchymal cells. FK506, an immunosuppressant often used clinically, induced a dose‐ and time‐dependent increase in alkaline phosphatase (ALP) activity, one of the markers of osteoblast differentiation, in cells derived from mesenchyma. In the presence of BMP‐4, ALP activity, mRNA levels of ALP and osteocalcin increased. FK506 was found to not only stimulate osteoblastic differentiation, but also to enhance BMP‐4 induced osteoblastic differentiation. These results suggest that FK506 promotes differentiation of osteoblastic cells.
OPPOSITE EFFECT OF LINEARLY POLARIZED LIGHT ON BIOSYNTHESIS OF INTERLEUKIN‐6 IN A HUMAN B LYMPHOID CELL LINE AND PERIPHERAL HUMAN MONOCYTES
Authors: Fenyö M. , Mandl J. , Falus A.
Published: October 2002

The effects of linearly polarized light (LPL) and diffuse light (DL) on the in vitro interleukin‐6 (IL‐6) production in a human B lymphoma cell line (BMNH) and peripheral monocytes of healthy volunteers were compared. Our data show that there was a significant increase of IL‐6 and IgM production in BMNH after exposure to LPL. The increase in IgM secretion was a consequence of its autocrine regulation by IL‐6, since in the presence of anti‐IL‐6 and anti‐IL‐6 receptor antibodies the LPL‐induced IgM secretion was abolished. In contrast to the stimulatory effect on B cells, exposure of human mononuclear phagocytes to LPL markedly reduced the production of IL‐6 induced by subsequent stimulation of cells with bacterial endotoxin (LPS). The inhibition as most pronounced when suboptimal doses of LPS were applied. Under identical experimental conditions, DL had no effect on the IL‐6 and IgM production of either B cells or monocytes.
SODIUM BUTYRATE STIMULATES THE SYNTHESIS OF FIREFLY LUCIFERASE IN TRANSFECTED CHO CELLS BUT LEVELS OF BiP CHAPERONE ARE UNAFFECTED
Authors: Winge Ingeborg , Pryme Ian F.
Published: October 2002

A stably transfected CHO cell line (LUCLEAD) was used where the coding region of native Firefly luciferase was linked to the 3′‐UTR of the bovine growth hormone, and the 5′‐nucleotides coding for the albumin signal peptide were linked to the N‐terminal end of the luciferase coding region. Incubation of cells with 1 or 2mM sodium butyrate (SB) for 72h had no effect on cell growth since cultures reached confluency at the same time as control cells. Although cell cultures incubated with SB at a concentration of 4mM were only about 60% confluent the luciferase content was about 5‐fold higher than that in control cells. Cells incubated with either 1 or 2mM SB showed intermediate levels of luciferase content. The amount of the chaperone BiP in the cells was not affected by incubation with SB. The results indicate that SB can be used to effectively promote synthesis of recombinant luciferase.
BCL‐2 DOES NOT CONTROL PROGRAMMED CELL DEATH IN THE IPLB‐LdFB CELL LINE FROM THE INSECT LYMANTRIA DISPAR
Authors: Ottaviani Enzo , Malagoli Davide
Published: October 2002

In the insect Lymantria dispar cell line IPLB‐LdFB the presence of a Bcl‐2‐like molecule has been demonstrated. The Western blot analysis performed on the cells incubated with 2‐deoxy‐D‐ribose (dRib), an apoptotic inducer, revealed that, in comparison with the control, the Bcl‐2 expression was unaffected. Furthermore, incubation of the insect cells with an anti‐Bcl‐2 polyclonal antibody inhibited the apoptotic effect induced by dRib, and provoked mitochondrial membrane depolarization without any apoptotic phenomena. Similar behaviour was observed using the K+ ionophore valinomycin. From these findings, we hypothesize that the L. dispar Bcl‐2‐like protein is essential for maintenance of the mitochondrial membrane potential, but not, as usually thought, for the regulation of programmed cell death.
CORRELATION BETWEEN CELL SURVIVAL, CLONOGENIC ACTIVITY AND MICRONUCLEI INDUCTION IN DMBA‐OC‐1R CELLS TREATED WITH IMMUNOSPECIFIC ALBUMIN MICROSPHERES CONTAINING CISPLATIN AND 5‐FLUOROURACIL
Authors: Truter Ernest J. , Santos Aldina S. , Els Willem J.
Published: October 2002

An ideal chemotherapeutic strategy would be to deliver a high concentration of drug that would be released in sustained small amounts from targeted microspheres to effectively kill only the tumour cells and thus reduce toxicity to normal tissue. Clonogenic and cell survival growth curve assays, as well as the micronucleus assay, were used to determine the feasibility of employing targeted immunomicrospheres in the treatment of cancer. Cells of a rodent ovarian carcinoma cell line, were exposed to cisplatin and 5‐fluorouracil, either as free drug or encapsulated in albumin microspheres that were either conjugated to monoclonal antibodies or not. In cell survival growth curve assays, cell survival was reduced to 1.2% of the control when cells were treated with drug‐containing immunomicrospheres. 3.2‐fold more micronuclei were found in those cells that had been exposed to the drugs in immunomicrospheres than in those subjected to untargeted microspheres. All three assays demonstrated that the targeted immunomicrospheres were more effective in delivering cisplatin and 5‐fluorouracil directly to the cells than the unconjugated microspheres, thus suggesting that targeted chemotherapy might be a more effective option in the treatment of cancer.
EXPRESSION AND POST‐TRANSLATIONAL MODIFICATION OF HUMAN 4‐HYDROXY‐PHENYLPYRUVATE DIOXYGENASE
Authors: Aarenstrup Lene , Falch Anne‐Marie , Jakobsen Kirsten K. , Neve Søren , Henriksen Linda Ø , Tommerup Niels , Leffers Henrik , Kristiansen Karsten
Published: October 2002

4‐hydroxyphenylpyruvate dioxygenase (HPD) (EC 1.13.11.27) is a key enzyme involved in tyrosine catabolism. Congenital HPD deficiency is a rare, relatively benign condition known as hereditary type III tyrosinemia. The severe type I tyrosinemia, caused by a deficiency of fumarylacetoacetate hydrolase which functions downstream of HPD in the tyrosine degradation pathway, is often associated with decreased expression of HPD, and interestingly, inhibition of HPD activity seems to ameliorate the clinical symptoms of type I tyrosinemia. The HPD gene was previously mapped to the chromosomal region 12q24→5;qter. In the present study high‐resolution chromosome mapping localized the HPD gene to 12q24.31. DNase I footprinting, revealed that four regions of the HPD promoter were protected by rat liver nuclear proteins. Computer‐assisted analyses suggested that these elements might bind Sp1/AP2, HNF4, HNF3/CREB, and C/EBP, respectively. In transient transfection experiments, the proximal 271bp of the promoter conferred basal transcriptional activation in human Chang cells. Sequences in intron 1 were able to enhance the activity of this basal promoter. Finally, vaccinia virus‐based expression provided evidence that HPD is subject to phosphorylation, and furthermore, allowed mapping of the HPD protein in the human keratinocyte 2D database.
Reinterpretation of Late Quaternary Sediment Chronology of Lake Biwa, Japan, from Correlation with Marine Glacial-Interglacial Cycles
Authors: Meyers Philip A. , Takemura Keiji , Horie Shoji
Published: October 2002

A review of published stratigraphic records of pollen, sediment grain size, diatoms, and organic matter composition from Lake Biwa, Japan, identifies four pre-Holocene episodes of milder climate, increased surface runoff, and enhanced aquatic productivity, indicating intervals of warmer and wetter conditions which are interpreted as being interglacial. Correlation of these episodes to times of marine interglacial periods revises the age scale of the Lake Biwa sediment sequence which has been based on fission-track dating. The revised chronostratigraphic scale proposes an age of ca. 430,000 yr B.P. for the base of the 250-m-thick T Bed instead of the former age of ca. 700,000 yr B.P.
Alluvial Soil Chronosequence in the Inner Coastal Plain, Central Virginia
Authors: Howard Jeffrey L. , Amos Dan F. , Daniels W. Lee
Published: October 2002

A chronological sequence of soils formed on a series of alluvial depositional surfaces ranging in age from late-middle Miocene to late Pleistocene was characterized to clarify soil-geomorphic relations and provide a basis for allostratigraphic subdivision of the inner Coastal Plain. On Quaternary river terraces, Ultic Hapludalfs containing abundant weatherable mineral species and clast types are estimated to have formed in 60,000-120,000 yr, whereas Typic Hapludults greatly depleted in weatherable minerals and showing strong weathering of clast types are estimated to be 700,000-1,600,000 yr old. Typic Paleudults with incipient plinthite, duripan, and ferricrete development characterize interfluves that have been little eroded since early Pliocene time (3.4-5.3 myr ago). Typic-Plinthic Paleudults with intense weathering of siliceous clasts and moderate to strong duripan and ferricrete development are found on surfaces that formed near the beginning of late Miocene time (10.8-13.0 myr ago). Chemical weathering in the chronosequence may be classified into three progressive stages: (1) decomposition of unstable sand- and silt-sized minerals into a mixed (stable + unstable) clay-mineral suite (stable Fe + Al/Si bulk chemical composition, < 106 yr); (2) transformation of mixed clay-mineral suite into a stable suite (increasing Fe + Al/Si bulk chemical composition, 106 - 107 yr); and (3) transformation of stable suite into ultrastable clay-mineral suite (increasing Fe/Si bulk composition, > 107 yr). Not all soil properties show unidirectional development, nor is a steady state of pedon development observed even after approximately 107 yr of chemical weathering. Soil development in the chronosequence is episodic. The transition from one phase to the next is marked by a change in rate, and sometimes a reversal in the direction, of development of one or more soil properties.
Reconstruction of Holocene Precipitation Patterns in Europe Using Pollen and Lake-Level Data
Authors: Guiot Joël , Harrison Sandy P. , Prentice I. Colin
Published: October 2002

Lake-level data can be used to refine palaeoclimate reconstructions based on pollen data. This approach is illustrated for the European Holocene. Estimates of P-PET (precipitation minus potential evapotranspiration) were first inferred from modern pollen analogues. The pollen-based estimates were then compared with the status of lakes within a 5° radius. Analogues with P-PET anomalies inconsistent with the lake-level changes were rejected. The "constrained" sets of analogues were used to estimate continental-scale patterns of annual mean temperature and annual precipitation at 3000-yr intervals. Estimated temperature anomalies differed only slightly from the unconstrained reconstructions. Estimated precipitation anomalies, however, showed improved spatial coherence and increased regional contrast and were occasionally reversed in sign. The effect of the constraint was to impose a rational selection among almost equally similar modern pollen analogues with similar temperatures but widely varying moisture regimes. The resulting maps showed clear, spatially coherent patterns of change in precipitation as well as temperature, suitable for comparison with climate-model results. Further improvement of these maps will become possible as a more extensive coverage of lake-level data is obtained.
Holocene Paleofloods of the Ross River, Central Australia
Authors: Patton Peter C. , Pickup Geoff , Price David M.
Published: October 2002

The rivers of central Australia rise in the MacDonnell Ranges and flow out across broad, low-relief plains into the surrounding desert. The stratigraphy of the Ross River plain records the areal extent and frequency of Holocene floods. This floodout plain is underlain by deeply weathered alluvial deposits, characterized by red earth soils dated by thermoluminesence at >59,000 yr. This old alluvium is covered by a sheet-like deposit of very silty sand of probable eolian origin dated by thermoluminesence at 9200 ± 900 yr. The oldest Holocene alluvium occurs as broad, low-relief bars and levee deposits flanking the modem channel and as low-relief long-wavelength bedforms that fan out across the plain. This deposit resulted from a flood flow, up to 10 km wide, that covered the entire plain. Evidence for several large floods between 1500 and 700 yr B.P. is also preserved in a 500- to 1500-m-wide paleochannel. Thus, the surface features on the floodout plains are the product of a few rare large flood events. This paleohydrologic record is additional evidence of the dynamic nature of the hydrometerological regime of central Australia.
Evidence Suggesting That Methods of Rock-Varnish Cation-Ratio Dating Are neither Comparable nor Consistently Reliable
Authors: Bierman Paul R. , Gillespie Alan R.
Published: October 2002

Using samples from a prehistoric quarry site in the Mojave Desert, we tested and compared the two principal methods of rock-varnish cation-ratio dating, analysis of rock-varnish scrapings (R. I. Dorn, 1983, Quaternary Research 20, 49-73 and 1989, Physical Geography 13, 559-596) and analysis of rock varnish in situ (C. D. Harrington and J. W. Whitney, 1987, Geology 15, 967-970). Because we found no consistent relationship between the varnish cation ratio (K + Ca)/Ti, and the relative age of the varnish, neither method could be used to "cation-ratio date" the underlying chert artifacts. Moreover, in situ analyses yielded systematically higher cation ratios and lower Ti abundances than bulk analyses of scraped varnish or microprobe analyses of varnish in cross section. Our results, when considered along with other recently published evidence, indicate that these two methods of varnish chemical analysis and cation-ratio dating may not be comparable, nor consistently reliable, chronometers.
Heterogeneity, Correlatives, and Proposed Stratigraphic Nomenclature of Hayes Tephra Set H, Alaska
Authors: Riehle James R.
Published: October 2002

Several Holocene tephra deposits of Hayes volcano constitute a marker horizon in southern and east-central Alaska. Their identification is aided by high amphibole/pyroxene ratio and biotite in trace amounts, unique among Holocene tephra deposits of the region. However, correlations are obscured by chemical heterogeneity of the glass which occurs at a scale less than the size of a lapilli. Single-shard analyses confirm that the heterogeneity is due neither to fractionation nor to plagioclase microlites. The heterogeneity may be due to mixing of magmas prior to eruption. It is proposed that the deposits be informally called Hayes tephra set H.
Grain Size of Quartz as an Indicator of Winter Monsoon Strength on the Loess Plateau of Central China during the Last 130,000 Yr
Authors: Xiao Jule , Porter Stephen C. , An Zhisheng , Kumai Hisao , Yoshikawa Shusaku
Published: October 2002

The Chinese loess-paleosol sequence constitutes an important record of variations in Asian monsoon climate over the past 2.4 myr. Magnetic susceptibility of loess and paleosols has been used as a proxy for summer monsoon intensity, while median grain size has been regarded as a measure of the strength of winter monsoon winds that were responsible for most of the dust transport. However, median grain size is only an approximate index of winter monsoon strength because both paleosols and loess have been modified, to various degrees, by weathering processes that have produced pedogenic clay. The quartz component of loess and paleosols is largely unaffected by weathering processes and therefore constitutes a more reliable proxy index of monsoon wind strength. Median grain size (Qmd) and maximum grain size (Qmax) values of monomineralic quartz isolated from the loess-paleosol section at Luochuan in the central Loess Plateau are characterized by two main intervals during the last ca. 130,000 yr when these parameters were significantly greater than 9 and 85 μm, respectively, and three main intervals when they were lower. The data imply that the winter monsoon weakened during the intervals with low Qmd and Qmax values, which coincide with marine oxygen isotope stages 5, 3, and 1, and was strongest ca. 67,000 and 20,000 yr ago during isotope stages 4 and 2. However, both quartz grainsize records display second-order high-frequency, high-amplitude variations, which are lacking in the magnetic susceptibility record, that imply rapid and significant changes in atmospheric conditions that affect dust transport and deposition.
The Eem Stable Isotope Record along the GRIP Ice Core and Its Interpretation
Authors: Johnsen Sigfus J. , Clausen Henrik B. , Dansgaard Willi , Gundestrup Niels S. , Hammer Claus U. , Tauber Henrik
Published: October 2002

A 3029-m-long deep ice core extending nearly to bedrock has been drilled at the very top of the Greenland ice sheet (Summit) by the Greenland Ice-core Project (GRIP), an international European joint effort organized by the European Science Foundation. The ice core reaches back to 250,000 yr B.P. according to dating based partly on stratigraphic methods and partly on ice-flow modeling. A continuous and detailed stable isotope (δ18O) profile along the entire core depicts dramatic temperature changes in Greenland through the last two glacial cycles, including abrupt climatic shifts during the Eem/Sangamon Interglaciation, which is elsewhere recorded as a warm and stable period. The stratigraphic continuity of the Eemian layers has therefore been scrutinized. New ice core studies, comprising cloudy band observations, deconvolution, and frequency analyses, lead to the conclusion that the climate instability suggested during the Eem Interglaciation in Greenland is likely to be real, though no conclusive evidence is available. Whereas latitudinal displacements of the North Atlantic Ocean current are considered the immediate cause of the glacial climate instability, longitudinal displacements may be the immediate cause of the Eemian instability. If so, the Eemian climate changes will be much subdued outside the Arctic region and will probably only be recognizable in sedimentary sequences of high sensitivity and temporal resolution.
U-Series Dating by the TIMS Technique of Land Snails from Paleosols in the Canary Islands
Authors: Hillaire-Marcel Claude , Ghaleb Bassam , Gariépy Clément , Zazo Cari , Hoyos Manolo , Goy Jose-Luis
Published: October 2002

A sequence of seven superimposed paleosols developed on eolian calcarenites and alluvium was sampled on the island of Lanzarote in order to examine the possibility of dating land snail shells by the U-series method, using a TIMS technique allowing measurement of U and Th isotopes in very small samples. In the lower six units, the fossil shells yielded D-allo/L-isoleucine (A/I) ratios of about 0.5 and apparent AMS 14C ages ranging from 41,000 to 34,000 yr B.P., indicating that most paleosols formed during a relatively short mid-Würm humid episode. The upper unit (paleosol 7) yielded more variable A/I ratios (ranging from 0.6 to 0.2) and a younger 14C age ∼27,000 yr B.P. Most samples contained enough U to allow the calculation of U-series ages, after correction for the presence of a detrital component. In samples containing a few tens of ppb of U (paleosols 1, 2, 3, 6, and 7), the ages are strongly dependent upon the model used for the correction. In samples containing more than 300 ppb of U (paleosols 4 and 5), concordant ages of ∼31,000 ± 1000 yr were obtained regardless of the correction model used. U uptake in these shells occurred during one single early diagenetic phase, soon after burial, since shells of modern snails do not contain any significant amount of U. The arid conditions subsequent to the mid-Würm humid episode have likely ensured since then a fair closure of the radioactive system.
Age of Sheep Creek Tephra (Pleistocene) in Central Alaska from Thermoluminescence Dating of Bracketing Loess
Authors: Berger Glenn W. , Péwé Troy L. , Westgate John A. , Preece Shari J.
Published: October 2002

The age of the Sheep Creek tephra (SCt), a widespread marker ash bed in eastern Alaska and western Yukon Territory, has been ambiguous and controversial. We have obtained three reliable thermoluminescence age estimates from bracketing loess near Fairbanks that imply a deposition age of about 190,000 ± 20,000 yr for SCt. Three of six loess samples near and closely bracketing the SCt beds near Fairbanks yielded younger age estimates (∼117,000 and ∼135,000 yr), most likely (based on field aspects) because of reworking and contamination by translocated grains. The new, reliable age assignment of 190,000 yr confirms independent stratigraphic evidence of a pre-last interglaciation age, and stratigraphic evidence from one site (Upper Eva Creek) that SCt is older than the more-widespread 140,000-yr-old Old Crow tephra. The SCt age also has implications for regional correlations of glacial and nonglacial deposits. In particular, it supports the stratigraphic and geomorphic interpretation that the Delta Glaciation in the east-central Alaska Range and the Reid Glaciation in western Yukon Territory are older than the last interglaciation (isotope substage 5e).
Timing and Extent of Late Quaternary Paleolakes in the Trans-Pecos Closed Basin, West Texas and South-Central New Mexico
Authors: Wilkins David E. , Currey Donald R.
Published: October 2002

The Trans-Pecos Closed Basin is a hydrographically closed region covering 20,000 km2centered on Salt Basin, 160 km east of El Paso, Texas. Geomorphic and limnetic evidence have been used to identify four major highstands for Lake King during the last glacial maximum (LGM). Additional geomorphic features from a second, recently identified, paleolake, Lake Sacramento, have been found in the Beargrass subbasin, a nested subbasin approximately 75 km northwest of Salt Basin. Radiocarbon ages of the organic material in Lake King sediments date four abrupt climate changes and rapid lacustrine transgressions during the LGM with a quasi-periodicity of 2000 yr. Geomorphic evidence in the Beargrass subbasin identifies lake cycles contemporaneous with those in Lake King. The dates for these transgressions correlate with the dates of freshening events identified by researchers in paleolake basins elsewhere in New Mexico. The quasi-periodicity of the events approximates that of Dansgaard–Oeschger events identified from Greenland ice cores. The contemporaneity of the Trans-Pecos transgressions with transgressive events in other basins in the region suggests that paleolakes in the region were in phase with respect to abrupt climate changes during the latter stages of the LGM.
The Mass Balance of Circum-Arctic Glaciers and Recent Climate Change
Authors: Dowdeswell Julian A. , Hagen Jon Ove , Björnsson Helgi , Glazovsky Andrey F. , Harrison William D. , Holmlund Per , Jania Jacek , Koerner Roy M. , Lefauconnier Bernard , Ommanney C. Simon L. , Thomas Robert H.
Published: October 2002

The sum of winter accumulation and summer losses of mass from glaciers and ice sheets (net surface mass balance) varies with changing climate. In the Arctic, glaciers and ice caps, excluding the Greenland Ice Sheet, cover about 275,000 km2of both the widely glacierized archipelagos of the Canadian, Norwegian, and Russian High Arctic and the area north of about 60°N in Alaska, Iceland, and Scandinavia. Since the 1940s, surface mass balance time-series of varying length have been acquired from more than 40 Arctic ice caps and glaciers. Most Arctic glaciers have experienced predominantly negative net surface mass balance over the past few decades. There is no uniform recent trend in mass balance for the entire Arctic, although some regional trends occur. Examples are the increasingly negative mass balances for northern Alaska, due to higher summer temperatures, and increasingly positive mass balances for maritime Scandinavia and Iceland, due to increased winter precipitation. The negative mass balance of most Arctic glaciers may be a response to a step-like warming in the early twentieth century at the termination of the cold Little Ice Age. Arctic ice masses outside Greenland are at present contributing about 0.13 mm yr−1to global sea-level rise.
Absence of Last Glacial Maximum Records in Lowland Tropical Forests
Authors: Ledru Marie-Pierre , Bertaux Jacques , Sifeddine Abdelfettah , Suguio Kenitiro
Published: October 2002

Environmental conditions of the lowland tropical forests during the last glacial maximum (LGM) between ca 20,000 and 18,000 14C yr B.P., are reevaluated in terms of dating control and lithology analyzed in seven pollen records from South America. The reevaluation shows that probably in none of the published records are LGM sediments present or abundant. This conclusion is based on the occurrence of abrupt lithologic changes coupled with changes in sedimentation rate interpolated from radiocarbon dates. These findings suggest that the LGM was represented probably by a hiatus of several thousand years, indicative of drier climates than before or after.
Glacioisostasy and Lake-Level Change at Moosehead Lake, Maine
Authors: Balco Greg , Belknap Daniel F. , Kelley Joseph T.
Published: October 2002

Reconstructions of glacioisostatic rebound based on relative sea level in Maine and adjacent Canada do not agree well with existing geophysical models. In order to understand these discrepancies better, we investigated the lake-level history of 40-km-long Moosehead Lake in northwestern Maine. Glacioisostasy has affected the level of Moosehead Lake since deglaciation ca. 12,500 14C yr B.P. Lowstand features at the southeastern end and an abandoned outlet at the northwestern end of the lake indicate that the lake basin was tilted down to the northwest, toward the retreating ice sheet, by 0.7 m/km at 10,000 14C yr B.P. Water level then rose rapidly in the southeastern end of the lake, and the northwestern outlet was abandoned, indicating rapid relaxation of landscape tilt. Lowstand features at the northwestern end of the lake suggest that the lake basin was tilted to the southeast at ca. 8750 14C yr B.P., possibly as the result of a migrating isostatic forebulge. After 8000 14C yr B.P., water level at the southeastern end was again below present lake level and rose gradually thereafter. We found no evidence suggesting that postglacial climate change significantly affected lake level. The rebound history inferred from lake-level data is consistent with previous interpretations of nearby relative sea-level data, which indicate a significantly steeper and faster-moving ice-proximal depression and ice-distal forebulge than geophysical models predict.
Late Quaternary Glaciation and Postglacial Stratigraphy of the Northern Pacific Margin of Canada
Authors: Barrie J. Vaughn , Conway Kim W.
Published: October 2002

Areas of southeastern Alaska and the Queen Charlotte Islands of the northwestern Pacific coast of North America were considered to be ice free during the late Wisconsinan glaciation and glacial refugia existed. However, a glacier extended from mainland North America to the shelfbreak in Dixon Entrance separating Alaska and the Queen Charlotte Islands. Glacial retreat to the east began sometime after 15,000 to 16,00014C yr B.P. and ice had completely left Dixon Entrance by 13,500 to 13,00014C yr B.P. A rapid sea-level regression occurred soon after deglaciation began, due to isostatic rebound, with relative sea level falling to approximately 150 m below present in central Dixon Entrance, decreasing the size of the inlet by about 30 percent by 12,40014C yr B.P. The late Quaternary glacial and postglacial stratigraphic sequence is more than 100 m thick overlying older Pleistocene sediments and Tertiary bedrock. A late Wisconsinan diamicton is overlain by glaciomarine muds formed between approximately 14,400 and 13,00014C yr B.P. Contemporaneous with the deposition of the glaciomarine muds an extensive outwash deposit formed off the northern coast of the Queen Charlotte Islands to a present depth of 150 m. During the sea-level lowstand and subsequent transgression, a reworked sand unit was deposited over much of the seafloor to depths greater than 450 m. The unit is exposed at the seafloor over much of the region, suggesting that seabed hydrodynamic energy levels were high after 13,00014C yr B.P. and remain so today.
Variation of Rb/Sr Ratios in the Loess-Paleosol Sequences of Central China during the Last 130,000 Years and Their Implications for Monsoon Paleoclimatology
Authors: Chen Jun , An Zhisheng , Head John
Published: October 2002

Rb, Sr, and magnetic susceptibility have been measured in the last interglacial–glacial loess profiles at Luochuan and Huanxian, central China. A high degree of similarity between the parameters in both profiles suggests that variations of Rb/Sr ratios in the sequence can be regarded as an indicator of East Asian summer monsoon strength. Matching the Rb/Sr record with the SPECMAP δ18O curve suggests that the Rb/Sr ratio responds sensitively to changes of the East Asian monsoon induced by global ice-volume variation.
Late Quaternary Temperature Variability in the Benguela Current System Derived from Alkenones
Authors: Kirst Georg J. , Schneider Ralph R. , Müller Peter J. , von Storch Isabel , Wefer Gerold
Published: October 2002

Three sediment cores on a transect across the continental slope off Namibia at about 23°S were investigated for alkenone-derived past sea-surface temperature (SST) and total organic carbon (TOC) content. These records are used to reconstruct variations of surface circulation, coastal upwelling, and paleoproductivity in the northern Benguela Current System for the last 150,000 yr. The SST record most distant from the coast resembles a SST pattern typical of the pelagic ocean, with the lowest SST at full-glacial periods and the highest SST during the Eemian and the Holocene. In contrast to the modern conditions where annual mean SST decreases toward the coast, the shelf-edge SST record has the most prominent warm anomalies of about 2°C during isotope stages 2 and 6 compared with the open ocean. The glacial SST minimum in the record close to the shelf is observed between 50,000 and 35,000 yr B.P., while the record midway along the transect shows intermediate temperature conditions between the offshore and nearshore records. The causal process for the warm anomalies under full ice-age conditions close to the coast may be similar to that of recent “Benguela Niño events” that originate from perturbations in the tradewind system over the western tropical Atlantic. During these events the Angola–Benguela Front, located at about 16°S, weakens and intensive southward protrusions of tropical water masses extend into the nearshore upwelling area as far as 25°S. Thus, the two nearshore records primarily responded to variations in the time-integrated balance between upwelling intensity and southward protrusions of anomalously warm and nutrient-poor Angolan surface waters, as indicated by the good anticorrelation of SST and TOC content. Accordingly, surface water cooling off Namibia over the last 150,000 yr was most intense during stage 3 due to strong winds that worked in favor of upwelling and a decrease of Angolan warm water influence.
Paleoclimate of Southwestern China for the Past 50,000 yr Inferred from Lake Sediment Records
Authors: Hodell David A. , Brenner Mark , Kanfoush Sharon L. , Curtis Jason H. , Stoner Joseph S. , Xueliang Song , Yuan Wu , Whitmore Thomas J.
Published: October 2002

Long sediment cores (12.5 and 13.5 m) from two lakes in Yunnan Province were used to infer the paleoclimate of southwest China over the past 50,000 yr. During the Holocene and marine isotope stage (MIS 3), bio-induced carbonate precipitation and organic matter (OM) production was high, suggesting warm temperatures and high primary productivity. In contrast, sediment inorganic carbon (IC) and organic carbon (OC) concentrations were low in last glacial deposits from 38,000 to 12,000 cal yr B.P., indicating cool temperatures and low productivity. The 50,000-yr record has alternating peaks of carbonate and coarse-grain (>38 μm) quartz that reflect warm, moist interglacial or interstadial conditions alternating with cold, dry glacial or stadial conditions, respectively. Spectral analysis of the carbonate and quartz signals reveals power concentrated at periods of 7200 and 8900 cal yr, respectively, that may reflect a nonlinear climate response to precessional forcing at a time of reduced eccentricity modulation (McIntyre and Molfino, 1996). Oxygen isotope values of calcite from Yunnan lake cores indicate the summer monsoon was weak during the last glaciation from 50,000 to 12,000 cal yr B.P. The summer monsoon intensified between 12,000 and 8000 cal yr B.P., but weakened gradually in response to insolation forcing during the mid-to-late Holocene. Our results support the Overpeck et al. (1996) model that posits a weak summer monsoon during the last glaciation that responded nonlinearly to insolation forcing when its intensity was affected by Eurasian snow cover and ice-sheet extent. The summer monsoon intensified and responded linearly to seasonal insolation forcing in the Holocene when ice volume diminished.
A First Step to Reconciling the GRIP and GISP2 Ice-Core Chronologies, 0–14,500 yr B.P.
Authors: Southon John
Published: October 2002

δ18O records from the GISP2 and GRIP ice cores are widely used as benchmark paleoclimate chronologies, but there are significant differences between the two time scales. The present study shows that offsets between the two chronologies over the past 14,500 yr do not accumulate gradually, but appear over two short intervals of 100–200 yr. An initial offset of 80 yr occurs close to 3300–3400 yr B.P., and another 100 yr of slip appears at the start of the Younger Dryas. Since these discrepancies are localized, resolving them may be far easier than if large sections of both cores required reexamination.
Primary hyperparathyroidism: Renal calcium excretion in patients with and without renal stone disease before and after parathyroidectomy
Authors: Frøkjaer Vibe G. , Mollerup Charlotte L.
Published: October 2002

The effect of parathyroidectomy on renal calcium excretion per 24 hours in patients with primary hyperparathyroidism with and without a history of renal stone disease was evaluated. Altogether, 91 patients operated on for primary hyperparathyroidism formed the study group for preoperative analysis. Of these patients, 42 were evaluated 1 to 3 years postoperatively. The median preoperative serum calcium level was 2.92 mmol/L, and it was the same for patients with or without renal stones. Preoperatively we found no differences in renal calcium excretion between patients with and without renal stone disease. The median renal calcium excretion was 6.80 mmol/24 hr. At 1 to 3 years after successful parathyroidectomy the group with renal stone disease had higher renal calcium excretion than the group without renal stones (p=0.03). The reduced effect of parathyroidectomy on renal calcium excretion in the patients with renal stone disease indicates that factors not related to the hyper‐parathyroid state could contribute to disturbances in renal calcium excretion and hence stone formation. In conclusion, the pathologic basis for renal stone formation in patients with primary hyperparathyroidism might not be the hyperparathyroid state alone; stone formation could be related to other predisposing factors as well. Therefore, although parathyroidectomy can cure hyperparathyroidism, the curative effect on renal stone disease should be reconsidered.
Long‐term survival of patients with stage IV hypopharyngeal cancer: Impact of fundus rotation gastroplasty
Authors: Schilling Martin K. , Eichenberger Martin , Maurer Christoph A. , Greiner Richard , Zbären Peter , Büchler Markus W.
Published: October 2002

Stage IV circular hypopharyngeal cancer is a disease with poor long‐term survival, and the only means of cure—surgery—is associated with high morbidity. All patients admitted with circular hypopharyngeal cancer and extension to the esophagus were enrolled in a multidisciplinary treatment protocol, including circular laryngopharyngoesophagectomy with tracheostomy, neck dissection, and pull‐up of a fundus rotation gastric tube that was anastomosed to the oropharynx. Five weeks postoperatively high‐dose radiotherapy (60 Gy) was given to the cervical region. Altogether, 18 qualifying patients were explored cervically, were found to have resectable lesions (i.e., without carotid artery infiltration), and were included in the protocol. After laryngopharyngoesophagectomy, an elongated gastric tube was pulled up to the oropharynx. The average distance bridged with the tube was 32±4 cm. No anastomotic leaks were found on postoperative Gastrografin swallow, and oral feeding was started between days 5 and 8. Patients were discharged with normal oral feeding on day 21 (±17 days). Diarrhea, postprandial fullness, and reflux resolved within 6 months postoperatively. Five patients died during the follow‐up period of 42 months (range 3–63 months): three due to cardiac events 18 and 38 months postoperatively and two within 12 months with residual disease and tumor recurrence, respectively. The estimated 5‐year survival was 60%. We concluded that an aggressive multidisciplinary approach including circular laryngopharyngoesophagectomy, neck dissection, and high‐dose radiotherapy ascertains good long‐term survival and good functional results in patients with advanced hypopharyngeal cancer when the intestinal continuity is reconstructed with a fundus rotation gastroplasty.
Comparison of vital dye‐guided lymphatic mapping and dye plus gamma probe‐guided sentinel node biopsy in breast cancer
Authors: Cserni Gábor , Rajtár Mária , Boross Gábor , Sinkó Mária , Svébis Mihály , Baitás Béla
Published: October 2002

The optimal technique for sentinel lymph node biopsy (SLNB) is still debated. SLNB with peritumoral injection of Patent blue dye was performed in 129 clinically T1‐T2 and NO breast cancers in 127 patients (group A); it was later replaced by combined dye and radiocolloid‐guided SLNB preceded by lymphoscintigraphy in 72 breast cancer patients (group B). This study compares these two methods. All patients underwent completion axillary dissection. Means of 1.4 and 1.3 SLNs were identified in groups A and B, respectively. The mean number of non‐SLNs for the whole series was 14.9 (range 5–42). The first 53 cases of lymphatic mapping (dye only) comprised the institutional learning period during which the identification rate of at least 1 SLN in 30 consecutive attempts reached 90%. The identification rate for the subsequent 76 group A patients was 92%. The accuracy rate of SLNBs for overall axillary nodal status prediction and the false‐negative rate for group A patients (after excluding the learning‐phase cases) were 93% and 10%, respectively. All 72 group B cases had at least one SLN identified, and only one false‐negative case occurred in this group (accuracy and false‐negative rates of 99% and 3%, respectively). Both the dye‐only and the combined SLNB methods are suitable for SLN identification, but the latter works better and results in higher accuracy, a higher negative predictive value, and a lower false‐negative rate. It is therefore the method of choice.
Granulocyte elastase release and pulmonary hemodynamics in patients with mitral valvular disease
Authors: Gohra Hidenori , Mikamo Akihito , Okada Haruhiko , Hamano Kimikazu , Zempo Nobuya , Esato Kensuke
Published: October 2002

In patients with atrial septal defect in whom pulmonary hypertension could develop as a consequence of left‐to‐right shunt, the extent of neutrophil‐mediated lung injury induced by cardiopulmonary bypass (CPB) is related to the degree of increase in the preoperative pulmonary artery pressure. In the present study, we investigated the relationship between levels of granulocyte elastase (GEL) after CPB and preoperative pulmonary hemodynamics or changes in pulmonary function after the operation in patients with mitral valve disease, in whom pulmonary hypertension could develop as a result of pulmonary venous congestion. The plasma levels of GEL were measured before and after CPB in patients who underwent mitral valve replacement. Respiratory index (RI) was evaluated preoperatively and postoperatively. Preoperative pulmonary hemodynamics were determined within one month of the operation. Granulocyte elastase level rose significantly after CPB from baseline (134.3±44.6 mg/L versus 2042.1±1215.0 mg/L; p<0.001). Peak level of GEL was significantly correlated with preoperative systolic pulmonary artery pressure (r=0.71; p=0.020), mean pulmonary artery pressure (r=0.64;p=0.046), pulmonary capillary wedge pressure (r=0.68; p=0.032), and pulmonary‐to‐systemic arterial pressure ratio (r=0.64; p= 0.045), but not with the hemodynamic variables for pulmonary blood flow or pulmonary resistance. Moreover, the value of (Postoperative RI — Preoperative RI)/Preoperative RI was positively correlated with the peak level of GEL (r=0.76; p=0.011). In conclusion, in patients with mitral valvular disease, as in those with atrial septal defect, the increase in GEL level after CPB is proportional to the increase in preoperative pulmonary artery pressure, which may cause the accordant pulmonary vascular damage.
Risk indicators for varicose veins in forty‐ to sixty‐year‐olds in the tampere varicose vein study
Authors: Laurikka Jari O. , Sisto Tero , Tarkka Matti R. , Auvinen Ossi , Hakama Matti
Published: October 2002

The objectives of the study were to discover the main determinants for the prevalence of varicose veins in a general population, and to assess the possibilities for prevention of this common surgical disease. Varicose veins were evaluated in three defined cohorts of 3284 men and 3590 women aged 40, 50, and 60 years by using a validated questionnaire. The response rate was 75% among men and 86% among women, and varicose veins were determined by self‐assessment. Increasing age, female sex, childbirths, standing posture at work, higher weight or height, and positive family history were significantly associated with varicose veins in a univariate analysis. These factors were further taken into a multivariate logistic regression analysis, and female gender (adjusted odds ratio, OR 2.2), increasing age (OR 2.2–2.8), a reported positive family history for varicose veins (OR 4.9), increasing number of births (OR 1.2–2.8), standing posture at work (OR 1.6), and higher weight (OR 1.2) and height (OR 1.4) were found to independent and significant risk indicators of varicose veins. Increasing age, positive family history of varicose veins, and child‐births in women were the most important factors in terms of population etiologic fractions. Familial predisposition and pregnancy‐related factors bear important associations with varicose veins. Thus prevention of varicose veins appears to be difficult. Varicose veins are nonlethal and, therefore, higher age is related to higher prevalence.
Changes in serum hyaluronic acid levels and expression of CD44 and CD44 mRNA in hepatic sinusoidal endothelial cells after major hepatectomy in cirrhotic rats
Authors: Saegusa Shotaro , Isaji Shuji , Kawarada Yoshifumi
Published: October 2002

Serum hyaluronic acid (HA) is widely distributed in connective tissues, and the majority of circulating HA is degraded by hepatic sinusoidal endothelial cells (SECs) via a receptor recycling pathway. Our previous clinical study revealed that monitoring serum HA levels after hepatectomy is useful in predicting the development of liver failure. In the present study, to determine the mechanism of the high HA levels after hepatectomy, especially in patients with liver cirrhosis, expression of the major HA receptor, CD44, and its mRNA was investigated in SECs isolated from rats with thioacetamide‐induced liver cirrhosis subjected to 70% hepatectomy (group I) and from rats with a normal liver that were subjected to 70% hepatectomy (group II). The 48‐hour postoperative survival rate in group I (13.3%) was significantly lower than in group II (100%). In group II, the expression of CD44 mRNA had increased significantly at 6 hours after hepatectomy, and this was followed by progressive increases in expression of CD44, indicating activation of SEC function. The increased serum HA levels after hepatectomy in group II became normal as CD44 expression increased. By contrast, the expression of CD44 and CD44 mRNA in group I was markedly attenuated after hepatectomy. The very low CD44 expression was followed by a significant and sustained increase in serum HA levels, indicating functional failure of the SECs. These results suggest that the significantly impaired functional reserve of SECs in liver cirrhosis is associated with increased mortality after 70% hepatectomy.