Linear response of east Greenland's tidewater glaciers to ocean/atmosphere warming.

Predicting the retreat of tidewater outlet glaciers forms a major obstacle to forecasting the rate of mass loss from the Greenland Ice Sheet. This reflects the challenges of modeling the highly dynamic, topographically complex, and data-poor environment of the glacier-fjord systems that link the ice sheet to the ocean. To avoid these difficulties, we investigate the extent to which tidewater glacier retreat can be explained by simple variables: air temperature, meltwater runoff, ocean temperature, and two simple parameterizations of "ocean/atmosphere" forcing based on the combined influence of runoff and ocean temperature. Over a 20-y period at 10 large tidewater outlet glaciers along the east coast of Greenland, we find that ocean/atmosphere forcing can explain up to 76% of the variability in terminus position at individual glaciers and 54% of variation in terminus position across all 10 glaciers. Our findings indicate that (i) the retreat of east Greenland's tidewater glaciers is best explained as a product of both oceanic and atmospheric warming and (ii) despite the complexity of tidewater glacier behavior, over multiyear timescales a significant proportion of terminus position change can be explained as a simple function of this forcing. These findings thus demonstrate that simple parameterizations can play an important role in predicting the response of the ice sheet to future climate warming.

Physical Conditions of Fast Glacier Flow: 3. Seasonally-Evolving Ice Deformation on Store Glacier, West Greenland.

Temporal variations in ice sheet flow directly impact the internal structure within ice sheets through englacial deformation. Large-scale changes in the vertical stratigraphy within ice sheets have been previously conducted on centennial to millennial timescales; however, intra-annual changes in the morphology of internal layers have yet to be explored. Over a period of 2 years, we use autonomous phase-sensitive radio-echo sounding to track the daily displacement of internal layers on Store Glacier, West Greenland, to millimeter accuracy. At a site located ∼30 km from the calving terminus, where the ice is ∼600 m thick and flows at ∼700 m/a, we measure distinct seasonal variations in vertical velocities and vertical strain rates over a 2-year period. Prior to the melt season (March-June), we observe increasingly nonlinear englacial deformation with negative vertical strain rates (i.e., strain thinning) in the upper half of the ice column of approximately -0.03 a-1, whereas the ice below thickens under vertical strain reaching up to +0.16 a-1. Early in the melt season (June-July), vertical thinning gradually ceases as the glacier increasingly thickens. During late summer to midwinter (August-February), vertical thickening occurs linearly throughout the entire ice column, with strain rates averaging 0.016 a-1. We show that these complex variations are unrelated to topographic setting and localized basal slip and hypothesize that this seasonality is driven by far-field perturbations in the glacier's force balance, in this case generated by variations in basal hydrology near the glacier's terminus and propagated tens of kilometers upstream through transient basal lubrication longitudinal coupling.

The occurrence and significance of fibronectin in livers from chronic alcoholics. An immunohistochemical study of early alcoholic liver injury.

The occurrence and distribution of fibronectin (FN) was assessed by an immunoperoxidase technique in liver biopsies from alcoholics without and with acinar zone 3 fibrosis of varying degrees. Increased amounts of FN was found diffusely in zone 3 areas with a perisinusoidal and pericellular localization. FN was closely correlating to the pattern of fibrosis but increased amounts of FN could also be seen in biopsies without fibrosis as visualized in Picro-Sirius stained sections. There was no topographical relationship to liver cells with fatty changes, Mallory bodies or to alcoholic hepatitis. It is made probable that FN is of significance in the development of early liver fibrosis in alcoholics and that FN may act as a chemotactic factor for collagen producing cells and as a skeleton for the new collagen formation.

Distribution of liver haemosiderin iron in 187 patients with various types of hepatic diseases.

The purpose of this study was to evaluate the distribution of haemosiderin iron in various regions of the liver (central, intermediary and peripheral hepatocytes, Kupffer cells, portal macrophages and bile duct epithelial cells) in 174 patients with different hepatic diseases (alcoholic cirrhosis (n = 49), alcoholic steatosis (n = 60), non-alcoholic cirrhosis (n = 16), acute hepatitis (n = 20), clinically overt untreated hereditary haemochromatosis (n = 3), miscellaneous disorders (n = 26)), and in 13 subjects with a normal liver biopsy. Furthermore, the relationship between liver haemosiderin iron, biochemical iron status markers and biochemical liver tests was investigated. In haemochromatosis iron was consistently present in all examined regions of the liver, and in 43% of patients with alcoholic liver disease haemosiderin was present in at least one region of the liver lobule. In 65% of patients with acute hepatitis, haemosiderin was present in macrophages and Kupffer cells. In other hepatic diseases and in normal livers, haemosiderin was rarely seen. Regression analyses showed a correlation between iron status markers in most patients, except in those with high serum aspartate aminotransferase levels. In conclusion, haemosiderin iron is distributed in a typical pattern in haemochromatosis, alcoholic liver disease and acute hepatitis. Both histochemical liver iron and serum ferritin are of value as indirect markers of liver iron stores in patients with moderate hepatocellular damage.

Six billion neurons lost in AIDS. A stereological study of the neocortex.

Human immunodeficiency virus type 1 (HIV1) is neurotropic. One of the morphological changes that is seen in patients with acquired immunodeficiency syndrome (AIDS) is cerebral atrophy affecting various structures including the neocortex. The cause of atrophy is not known. The total number of neocortical neurons was estimated in formalin fixed brains of 12 males with AIDS and 12 male controls matched for age and height. The mean number of neocortical neurons was 16.0 x 10(9) (coefficient of variation = 0.11) in the AIDS patients compared with 21.9 x 10(9) (coefficient of variation = 0.22) in the controls, a difference of approximately six billion (p < 0.005, 2-tailed). The global neuronal loss was 37%, and affected all four neocortical lobes. Ten patients did not have a history of central nervous system symptoms; two patients had a history of dementia. The number of neurons in the AIDS cases was not associated with dementia. AIDS is the first disease in which a global loss of neocortical neurons has been demonstrated using unbiased stereological methods. The loss of more than one third of the neurons may partly explain the cortical atrophy. Focal neuron loss has been reported by several authors, but none have been based on unbiased methods. In this group of AIDS patients the severe loss of neurons did not correspond to neurological deficits.

Liver histopathology of the hepatitis A virus infection: a comparison with hepatitis type B and non-a, non-b.

Liver biopsies from 86 patients with serologically established acute hepatitis A were evaluated for quantitative and qualitative light microscopic features together with biopsies from 78 patients with acute hepatitis type B and 76 patients with acute hepatitis type non-A, non-B. Hepatitis A was characterised by more pronounced portal inflammation than hepatitis non-A, non-B (p less than 0.01) but less conspicuous parenchymal changes (focal necrosis, Kupffer cell proliferation, acidophil bodies, ballooning) than found in hepatitis type B (p less than 0.01). Steatosis occurred in 10% of the hepatitis A biopsies compared with 26% (p less 0.01) and 6% (not significant) in the hepatitis non-A, non-B and B groups, respectively. A comparison between the histological findings in women and men revealed that iron deposits occurred in more than half of the men compared to less than 20% of the women (p less than 0.01) irrespective of hepatitis type. Histological and biochemical follow-up was available in 36 patients with hepatitis A. For the majority of these patients the bilirubin concentration reached normal values within one month of the initial biopsy. The activity of serum transaminases showed good correlation with the degree of histological resolution. Non-specific reactive hepatitis with slightly raised serum transaminases were often seen during recovery from hepatitis A. These patients may be misinterpreted as cases of acute non-A, non-B hepatitis.

Prevalence of hepatitis B virus infection among alcoholic patients with liver disease.

The aim of this investigation was to elucidate a possible role of hepatitis B virus (HBV) in the pathogenesis of liver diseases in alcoholics. Two hundred and fifty-three alcoholics with liver disease were admitted to two medical departments in Copenhagen during a 15 months period. Seventy-nine patients (31%) showed serological signs (HBsAg, anti-HBs) of previous or active HBV infection. This is a significantly higher prevalence than found in an age-matched control population. Among the 79 patients with HBV markers, a total of 11 was found to be HBsAg-positive. From these 11 patients liver specimens were available for re-evaluation in nine cases. In only three of these liver biopsies, morphological changes indicating alcohol as the aetiological cause were found. In conclusion, different or concomitant aetiology must be considered in alcoholics with liver disease.

Isolation of Mallory bodies and an attempt to demonstrate cell mediated immunity to Mallory body isolate in patients with alcoholic liver disease.

Mallory bodies were isolated from necropsy livers from patients with alcoholic hepatitis with and without cirrhosis with a Ficoll viscosity barrier. The purity of Mallory bodies in the isolate varied between 70 and 90%, estimated by counting Mallory bodies and non-Mallory body structures in haematoxylin-eosin stained smears. Electron microscopy confirmed the presence of Mallory bodies in the isolates. The Mallory body isolate was used as antigen in the agarose leucocyte migration inhibition test in order to test the cell-mediated immunity. No significant difference in leucocyte migration was found between controls and patients with alcoholic hepatitis, alcoholic steatosis, alcoholic cirrhosis and miscellaneous liver diseases.

Occurrence and type of chromosomal abnormalities in consecutive malignant monoclonal gammopathies: correlation with survival.

Chromosome studies were done on 73 patients with multiple myeloma and three patients with plasma cell leukemia. Eighteen of 76 patients (24%) had chromosomally abnormal clones, including all three patients with PCL. The most common anomalous chromosomes were #1, #14, and #12. In addition, i(17q) was found in two patients with plasma cell leukemia. Among newly diagnosed patients there was no difference in survival for those with abnormal karyotypes and those with normal karyotypes. Among previously diagnosed patients receiving treatment, however, individuals with an abnormal clone had a significantly higher mortality during the first 2 years compared to those with a normal clone. Patients with no growth of metaphases in their bone marrow aspirate had a significantly lower mortality than other patients (p less than 0.05).

Prolonged T1 in patients with liver cirrhosis: an in vivo MRI study.

Fifteen patients with liver cirrhosis and two control groups were examined. The first control group consisted of 7 healthy volunteers, and the second group of 17 patients with nonfocal liver diseases. The T1 and T2 relaxation times were calculated from signal intensities read out from a region of interest centrally located in the liver. T1 relaxation time was longer in the patients with liver cirrhosis than in the two reference groups. Ten patients had a liver biopsy taken prior to the MRI study. No correlation was found between histopathology and the measured relaxation times.

Prolonged bone marrow T1-relaxation in acute leukaemia. In vivo tissue characterization by magnetic resonance imaging.

In vivo tissue characterization by measurement of T1- and T2-relaxation processes is one of the greatest potentials of magnetic resonance imaging (MRI). This may be especially useful in the evaluation of bone marrow disorders as the MRI-signal from bone marrow is not influenced by the overlying osseous tissue. Nine patients with acute leukaemia, one patient with myelodysplastic syndrome, and ten normal volunteers were included in the study. The T1- and T2-relaxation processes were measured in the lumbar spine bone marrow using a wholebody superconductive MR-scanner operating at 1.5 Tesla. In the patients MRI was done at the time of diagnosis and during follow-up of chemotherapy and related to bone marrow biopsies taken within three days of the MRI. At the time of diagnosis T1-relaxation time was increased two to three times in the patients (range 0.7-3.0 sec.) compared to the controls (range 0.38-0.60 sec.). No significant difference was seen in the T2-relaxation process. In relation to chemotherapy T1 decreased towards the normal range in the patients who obtained complete remission, whereas T1 remained prolonged in the patients who did not respond successfully to the treatment. The results indicate that MRI may be a non-invasive clinically useful tool in the evaluation of acute leukaemia especially as a follow-up control of chemotherapy.

Quantification of liver fat using magnetic resonance spectroscopy.

Localized proton MR spectroscopy using stimulated echoes was used to quantify the liver fat concentration in patients with various degrees of fatty liver due to alcohol abuse. Ten patients underwent a liver biopsy followed by chemical triglyceride estimation of the fatty content. A statistically significant correlation was found between the fat concentration measured in the liver biopsies, and the concentration calculated from the spectroscopic experiments (r = 0.9, p < .001). Quantitative assessment of liver fat concentrations using localized spectroscopy is superior to methods based on differences in relaxation times, and can be used to estimate the fat concentration over the full range of fat content in contrast to the spectroscopic imaging methods. Localized spectroscopy may replace liver biopsy in the diagnosis of diffuse fatty infiltrations, and can be used for follow-up, due to its noninvasive nature.

Identification of patients with hereditary haemochromatosis by magnetic resonance imaging and spectroscopic relaxation time measurements.

A total of 4302 healthy blood donors were screened for elevated serum ferritin and transferrin saturation. Fifteen had increased serum ferritin at a follow-up examination. Five relatives of these donors also entered the study. Eleven patients had elevated liver iron concentrations, while five had normal liver iron concentrations. The R2 relaxation rate in the liver was first measured with a conventional multi-spin-echo imaging sequence, and then by a volume-selective spectroscopic multi-spin-echo sequence, in order to achieve a minimum echo time of 4 msec. No correlation was found between the relaxation rate R2 and the liver iron concentration, when R2 was calculated from the imaging data. Multi-exponential transverse relaxation could be resolved when the spectroscopic sequence was used. A strong correlation between the initial slope of the relaxation curve and the liver iron concentration was found (r = 0.90, p < 0.001). Signal intensity ratios between liver and muscle were calculated from the first three echoes in the multi-echo imaging sequence, and from a gradient echo sequence. A strong correlation between the logarithm of the signal intensity ratios and the liver iron concentration was found. Although both spectroscopic T2 relaxation time measurements and signal intensity ratios could be used to quantify liver iron concentration, the gradient echo imaging seemed to be the best choice. Gradient echo imaging could be performed during a single breath hold, so motion artifacts could be avoided. The accuracy of liver iron concentration estimates from signal intensity ratios in the gradient echo images was about 35%.

Prolonged bone marrow T1-relaxation in patients with polycythemia vera.

In vitro as well as in vivo studies have shown prolonged T1 relaxation times in patients with acute leukemia. The mechanism behind this finding is not known. In order to evaluate if this was specific for leukemia we examined eight patients with polycythemia vera, representing a condition with a rather benign bone marrow neoplasia. In this group of patients we found prolonged T1 relaxation times but normal T2 relaxation times. This may indicate that the prolonged T1 relaxation time seen in leukemic bone marrow is not due to the malignant cell per se.

Lymph-node and thymus pathology in fatal drug addiction.

Lymph-node sections from the porta hepatis, the lung hilus, the para-aortic and axillary regions and from the neck from totally 50 drug addicts submitted for medico-legal autopsy at the Institute of Forensic Medicine in Copenhagen were studied together with tissue sections from 23 normal persons. In addition thymus sections from 30 drug addicts and 20 normal persons were investigated. Enlargement of lymph-nodes was found significantly more often in active drug addicts compared to normals except for the nodes on the neck. Birefringent material was seen in portal lymph-nodes in 42% of addicts, in para-aortic and lung hilus nodes in 18% each and in the axillary nodes in 12%. Signs of antigenstimulation evaluated by the number of germinal centre and plasma cells were found in about 60% or more in active drug addicts compared to about 30-40% in normals. There was not significant relation between the size of the lymph-nodes and the immunoactivity nor to the duration of the abuse. Examination of the thymus showed that the average weight in active drug addicts was 34 g, in normals 25 g. Histologically the tissue was in 48% of the active addicts composed of more than 80% lymphatic tissue compared to 15% of the normals. The results indicate that the enlargement and histological signs of activation in all the lymph-nodes investigated are caused by continuous antigenstimulation due to repeated injections of various antigens. The same may in part be applied to the thymus changes demonstrated.

Lung and heart pathology in fatal drug addiction. A consecutive autopsy study.

Lung and heart sections from 33 drug addicts submitted for medico-legal autopsy at the Institute of Forensic Medicine in Copenhagen were studied together with tissue sections from 20 'normal' persons. In the drug addict cases focal bleedings in lung tissue were found in 94%, signs of earlier bleedings, haemosiderin containing histiocytes, were seen in 91%, and focal fibrosis in 46%. The bleeding episodes may be due to hypoxia in connection with heroin intake. In 94% of the drug addicts birefringent material in lung tissue was demonstrated, in 58% in granulomas and giant cells, in 27% in giant cells only and in 9% in isolated histiocytes. The material was localized in the wall of pulmonar arteries and/or in the interstitial tissue, undoubtedly depending on the duration of the abuse. In 18% angiothrombosis was seen, in all cases granulomas/giant cells were observed in the wall of the vessel concerned. The results indicate periodical intravenous injection of dissolved tablets in addition to heroin. Histological signs of pulmonary hypertension were not seen, possibly due to the fact that abuse of central stimulants is very rare in Denmark. Regarding heart alterations no significant differences were demonstrated between drug addicts and controls. The only note-worthy finding was focal infiltration of lymphocytes in the atrio-ventricular bundle in two drug addicts, the meaning of which is uncertain.

The nature and the occurrence of birefringent material in different organs in fatal drug addiction.

Insoluble birefringent tablet filler materials commonly found in tablets used in solution by drug addicts as intravenous injections were investigated microscopically. The following filler materials were investigated: talc, potato- and maize-starch, microcrystalline cellulose, magnesium stearate and siliciumoxid. The morphological characteristics of the different materials are described. Tissue sections (lung, liver, spleen, heart, bone-marrow, kidney, lymph-nodes and endocrine glands) from 33 consecutive fatality cases of intravenous drug addicts autopsied at the University Institute of Forensic Medicine in Copenhagen were studied with special reference to the occurrence and nature of birefringent material. Birefringent material was most often demonstrated in lung tissue (94%), followed by spleen (76%), liver (55%), lymph-nodes (portal: 39%) and bone-marrow (24%). The material was always localized intracellularly. Granulomatous reaction was only seen in the lungs. Except for one case, talc was the only foreign material seen in other organs than the lungs, undoubtedly due to its smaller size. The presence of insoluble foreign material in lung tissue of drug addicts indicates a habit of intravenous administration and the amount of the material indicates whether the addict usually injects tablets or only does so occasionally. The presence of birefringent material in the organs have only rarely any obvious clinical implications.

Morphological findings in fatal drug addiction. An investigation of injection marks, endocrine organs and kidneys.

Tissue sections from injection marks from 30 drug addicts and sections from endocrine organs and kidneys from an additional 33 addicts were studied together with endocrine organs and kidneys from 20 'normal' persons. All 83 persons were submitted for medico-legal autopsy at the Institute of Forensic Medicine in Copenhagen. In fresh injection marks haemorrhage in dermis and subcutis was present histologically in all cases. Acute inflammation was present in 38% and acute inflammation together with chronic changes in 41%. Fibrotic thickening of vein wall was seen in 14% and thrombosis in 10%. Birefringent foreign material occurred in 35%. In old injection marks and scars chronic inflammatory changes were observed in 93%, fibrotic thickening of vein wall in 20% and thrombosis in 10% of the cases. Birefringent material occurred in 17%. By comparison of changes in injection marks with the size and histological changes in the corresponding axillary lymph nodes, there was a tendency to a relation between chronic inflammatory changes in old injection marks/scars and enlargement of the lymph nodes in question, but no correlation to the histological degree of immunoactivity. Regarding alterations in the endocrine organs and the kidneys no important differences were demonstrated between drug addicts and 'normal' persons.

Spleen and portal lymphnode pathology in fatal drug addiction.

Spleen and portal lymphnode sections from 86 drug addicts submitted for medico-legal autopsy at the Institute of Forensic Medicine in Copenhagen in the year 1979 were studied together with tissue sections from 24 "normal" persons. In 70% of the drug addicts the spleen weight was more than 200 g, and in 71% portal lymphnode hyperplasia was found. Birefringent foreign material was found in spleen tissue of drug addicts in 72% and in portal lymphnode tissue in 44%. Signs of antigen stimulation in both spleen and portal lymphnode tissue evaluated by the number of germinal centre and plasma cells were found in more than 80% of the drug addicts compared with about 20% of the "normal" persons. The results were related to anamnestic information of duration of drug abuse, to the spleen weight, to the occurrence of birefringent material and to the liver changes. Examination of lysozyme and immunoglobulin containing cells using the indirect preoxidase technique was performed in a total of 72 cases of spleen tissue, 59 cases of portal lymphnode tissue from drug addicts, 24 cases of spleen tissue and 18 of portal lymphnode tissue from "normal" persons. Lysozyme, IgM and IgG containing cells were found significantly more often among drug addicts than "normal" persons. The results indicate that the splenomegalia and the portal lymphnode hyperplasia often found in drug addicts are caused by continuous antigen stimulation due to repeated injections of various antigens.

Liver pathology in fatal drug addiction.

Liver sections from 273 drug addicts submitted to medicolegal autopsy at the Institute of Forensic Medicine in Copenhagen in the period 1975-1979 were studied. In 65% of the cases non-specific portal inflammation only was found. Birefringent material--identified as the mineral talc (magnesium silicate) was observed in 38% of the cases; in these cases non-specific portal inflammation was always present. Changes compatible with acute or chronic persistent hepatitis or hepatitis sequelae were observed in 8% of the cases; cirrhosis in 3%. HBs-antigens were detected in 4%. In 22% fatty infiltration was present; in 4% as the only abnormal finding. Finally no pathological changes were found in 6%. The results were related to anamnestic information of kind and duration of drug abuse and to the cause of death. Furthermore a comparison was performed between the groups with and without birefringent material. The data suggest that the birefringent material may be of importance to the pathogenesis of the non-specific portal inflammation.