Melt rates in the kilometer-size grounding zone of Petermann Glacier, Greenland, before and during a retreat

Warming of the ocean waters surrounding Greenland plays a major role in driving glacier retreat and the contribution of glaciers to sea level rise. The melt rate at the junction of the ocean with grounded ice-or grounding line-is, however, not well known. Here, we employ a time series of satellite radar interferometry data from the German TanDEM-X mission, the Italian COSMO-SkyMed constellation, and the Finnish ICEYE constellation to document the grounding line migration and basal melt rates of Petermann Glacier, a major marine-based glacier of Northwest Greenland. We find that the grounding line migrates at tidal frequencies over a kilometer-wide (2 to 6 km) grounding zone, which is one order of magnitude larger than expected for grounding lines on a rigid bed. The highest ice shelf melt rates are recorded within the grounding zone with values from 60 ± 13 to 80 ± 15 m/y along laterally confined channels. As the grounding line retreated by 3.8 km in 2016 to 2022, it carved a cavity about 204 m in height where melt rates increased from 40 ± 11 m/y in 2016 to 2019 to 60 ± 15 m/y in 2020 to 2021. In 2022, the cavity remained open during the entire tidal cycle. Such high melt rates concentrated in kilometer-wide grounding zones contrast with the traditional plume model of grounding line melt which predicts zero melt. High rates of simulated basal melting in grounded glacier ice in numerical models will increase the glacier sensitivity to ocean warming and potentially double projections of sea level rise.

Global seasonal Sentinel-1 interferometric coherence and backscatter data set

This data set is the first-of-its-kind spatial representation of multi-seasonal, global C-band Synthetic Aperture Radar (SAR) interferometric repeat-pass coherence and backscatter signatures. Coverage comprises land masses and ice sheets from 82° Northern to 79° Southern latitudes. The data set is derived from multi-temporal repeat-pass interferometric processing of about 205,000 Sentinel-1 C-band SAR images acquired in Interferometric Wide-Swath Mode from 1-Dec-2019 to 30-Nov-2020. The data set encompasses three sets of seasonal (December-February, March-May, June-August, September-November) metrics produced with a pixel spacing of three arcseconds: 1) Median 6-, 12-, 18-, 24-, 36-, and 48-days repeat-pass coherence at VV or HH polarizations, 2) Mean radiometrically terrain corrected backscatter (γ⁰) at VV and VH, or HH and HV polarizations, and 3) Estimated parameters of an exponential coherence decay model. The data set has been produced to obtain global, spatially detailed information on how decorrelation affects interferometric measurements of surface displacement and is rich in spatial and temporal information for a variety of mapping applications.

Automatic delineation of glacier grounding lines in differential interferometric synthetic-aperture radar data using deep learning

Delineating the grounding line of marine-terminating glaciers-where ice starts to become afloat in ocean waters-is crucial for measuring and understanding ice sheet mass balance, glacier dynamics, and their contributions to sea level rise. This task has been previously done using time-consuming, mostly-manual digitizations of differential interferometric synthetic-aperture radar interferograms by human experts. This approach is no longer viable with a fast-growing set of satellite observations and the need to establish time series over entire continents with quantified uncertainties. We present a fully-convolutional neural network with parallel atrous convolutional layers and asymmetric encoder/decoder components that automatically delineates grounding lines at a large scale, efficiently, and accompanied by uncertainty estimates. Our procedure detects grounding lines within 232 m in 100-m posting interferograms, which is comparable to the performance achieved by human experts. We also find value in the machine learning approach in situations that even challenge human experts. We use this approach to map the tidal-induced variability in grounding line position around Antarctica in 22,935 interferograms from year 2018. Along the Getz Ice Shelf, in West Antarctica, we demonstrate that grounding zones are one order magnitude (13.3 ± 3.9) wider than expected from hydrostatic equilibrium, which justifies the need to map grounding lines repeatedly and comprehensively to inform numerical models.

Heterogeneous retreat and ice melt of Thwaites Glacier, West Antarctica

The glaciers flowing into the Amundsen Sea Embayment, West Antarctica, have undergone acceleration and grounding line retreat over the past few decades that may yield an irreversible mass loss. Using a constellation of satellites, we detect the evolution of ice velocity, ice thinning, and grounding line retreat of Thwaites Glacier from 1992 to 2017. The results reveal a complex pattern of retreat and ice melt, with sectors retreating at 0.8 km/year and floating ice melting at 200 m/year, while others retreat at 0.3 km/year with ice melting 10 times slower. We interpret the results in terms of buoyancy/slope-driven seawater intrusion along preferential channels at tidal frequencies leading to more efficient melt in newly formed cavities. Such complexities in ice-ocean interaction are not currently represented in coupled ice sheet/ocean models.

Mechanism of traumatic knee injuries and MRI findings

Bone bruises are focal abnormalities in subchondral bone marrow due to trabecular microfractures as a result of traumatic force. These trauma-induced lesions are better detected with magnetic resonance (MR) imaging using water-sensitive sequences. Moreover, the pattern of bone bruise is distinctive and allows us to understand the dynamics of trauma and to predict associated soft injuries. This article discusses the mechanism of traumatic injury and MR findings.

Treatment of radiculopathies: a study of efficacy and tollerability of paravertebral oxygen-ozone injections compared with pharmacological anti-inflammatory treatment

The study was performed to evaluate the effectiveness of lumbar paravertebral injections of a gas mixture of Oxygen and Ozone in patients with lumbar radiculopathies caused by L4-L5 or L5-S1 disk herniations compared to a pharmacological therapy based on non-steroidal anti-inflammatory drugs. Lumbar radiculopathy caused by disc herniation is widely spread. Many therapeutic options are available before steering patients to the surgery. Low back pain and sciatica represent some of the most frequent causes of antinflammatory-analgesic drugs overuse. Recent findings have shown that medical Ozone can be used in the treatment of radicular syndrome caused by herniated intervertebral discs. Although widely spread, there are insufficient published data supporting the effectiveness of this approach in clinical practice. We studied 38 affected patients with acute L5 or S1 radicolopathy. The patients were randomly divided in two groups: A) 20 patients treated with lumbar paravertebral injections of Oxygen and Ozone; B) 18 patients treated pharmacologically with antinflammatory-analgesic drugs. All patients underwent a clinical and neurological examination at baseline (T1) and after 1 (T2), 2 (T3), 4 weeks (T4) and after 3 (T5) and 6 months (T6). An MRI and EMG examination were performed at baseline and after 6 months. The intensity of pain and the outcome of treatments were evaluated in all patients with the Visual Analogue Scale and with the Oswestry Disability Index. We found a reduction of pain and discomfort soon after one week with oxygen-ozone injections compared with pharmacological treatment, but this difference of response became statistically significant after two weeks (50 percent vs 16.6 percent) and is confirmed after 3 and 6 months, when 80 percent of patients treated with injections turned out pain free compared with half of the patients treated pharmacologically. No statistical difference were found in MRI and EMG examinations. No adverse effects were found in any patient of group A. We hypothesize that oxygen-ozone injections in paravertebral regions can induce a direct reduction of root inflammation with a corresponding reduction of pain. The paravertebral injections of oxygen-ozone represent a rapidly effective therapy, easily practicable and secure, in patients with lumbar radicolopathies secondary to disc herniation.

Assessment of activity of Crohn's disease of the ileum and large bowel: proposal for a new multiparameter MR enterography score

PURPOSE

We evaluated the diagnostic accuracy of magnetic resonance enterography (MR-E) in assessing Crohn's disease (CD) activity by differentiating acute, chronic and remission stages of disease through a quantitative MR-E assessment.

MATERIALS AND METHODS

One hundred patients with a histological diagnosis of CD were studied with MR-E. Intestinal distension was obtained by oral administration of approximately 2 L of a polyethylene glycol solution (PEG). In all cases, the ileum and large bowel were imaged with morphological sequences (heavily T2-weighted single-shot, dual fast-field echo, balanced fast-field echo) and a postcontrast dynamic sequence (T1-weighted high-resolution isotropic volume excitation). Disease activity was assessed according to a multiparameter score (0-8) based on lesion morphology, signal intensity and contrast enhancement. MR-E findings were compared with clinical-laboratory data and disease activity indices [Crohn's Disease Activity Index (CDAI); Inflammatory Bowel Disease Questionnaire (IBDQ)]. Multiple regression analysis was performed by correlating MR-E score, CDAI and IBDQ. Frequencies were then compared using the χ (2) test.

RESULTS

MR-E identified inactive disease in 9% of cases, chronic disease in 57% and active disease in the remaining 34%. The most frequently involved bowel segment was the terminal ileum (52%). A statistically significant correlation was found between MR-E score and CDAI (R=0.86; p<0.001) and between MR-E score and IBDQ (R=-0.83; p<0.001). The most suggestive parameter for disease activity was layered bowel-wall enhancement, a finding predominantly present in patients with increased CDAI (≥ 150) and/or local complications (χ (2)=7.13; p<0.01).

CONCLUSIONS

MR-E is a noninvasive and diagnostic imaging modality for CD study and follow-up. The MR-E score proposed in this study proved to be useful in assessing disease severity and monitoring response to treatment.

Childhood Ataxia with Cerebral Hypomyelination Syndrome: A Variant of Patient with Early Childhood Onset Related to EIF2B3 Mutation

Childhood ataxia with central nervous system hypomyelination (CACH) syndrome is an autosomal recessive transmitted leukodystrophy characterised by early childhood onset and acute deterioration following febrile illnesses or head trauma. We describe the case of a child with early onset of CACH syndrome. He presented with cerebellar ataxia beginning around two years of age with mild mental retardation. MRI showed diffuse white matter signal changes with thinning of the corpus callosum.

Severe diffuse systemic amyloidosis with involvement of the pharynx, larynx, and trachea: CT and MR findings

Amyloidosis is a term applied to a diverse group of disorders that share the deposition of amyloid protein in various extracellular tissues. Systemic amyloidosis may involve almost any organ system in the body including regions in the head and neck; however, pharyngeal involvement is rare, with only 12 cases having been previously reported. Ten of these cases were localized disease, and only 2 cases were systemic amyloidosis. We present the case of a patient with severe diffuse systemic amyloidosis with extensive involvement of the pharynx, larynx, trachea, lungs, eyelids, and breasts. We also review the imaging characteristics and pertinent literature.

Jaw osteonecrosis in patients treated with bisphosphonates: MDCT evaluation

PURPOSE

This study was done to evaluate the use of multidetector computed tomography (MDCT) in the evaluation of jaw osteonecrosis, a recently described medical entity in patients receiving long-term intravenous or oral bisphosphonates, and to help radiologists recognise it to enable early diagnosis and appropriate management.

MATERIAL AND METHODS

Thirty-eight patients with a history of neoplasm (breast, prostate, multiple myeloma, pancreas) or osteoporosis and bisphosphonate use and recent oral surgery who presented with pain in the mouth and temporomandibular joints, soft tissue infections, altered taste and numbness were examined with MDCT.

RESULTS

In all patients, MDCT revealed the presence of structural bony alterations referable to osteonecrosis associated with orosinusal fistula in four of them and bony intraoral spicules in 25.

CONCLUSIONS

Jaw osteonecrosis is an established medical entity discovered in patients who have undergone treatment with bisphosphonates and dental extraction or other oral surgery. MDCT with multiplanar (MPR), volume rendering (VR) and three-dimensional (3D) reconstructions allows accurate assessment of affected bone structures, enabling early diagnosis and suitable treatment planning. Radiologists should be aware of the risk of osteonecrosis in patients treated with bisphosphonates and be able to distinguish it from other bone diseases (osteomyelitis and osteoradionecrosis) with which it enters the differential diagnosis.

Double-contrast MRI (DC-MRI) in the study of the cirrhotic liver: utility of administering Gd-DTPA as a complement to examinations in which SPIO liver uptake and distribution alterations (SPIO-LUDA) are present and in the identification and characterisation of focal lesions

PURPOSE

The aim of this study was to compare the performance of double-contrast magnetic resonance imaging (DC-MRI) with the sequential use of superparamagnetic iron oxide (SPIO) and gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) contrast agents compared with unenhanced MRI and SPIO-enhanced MRI (SPIO-MRI) in the study of the cirrhotic liver. Special attention was paid to cases in which alterations of liver uptake and distribution of the SPIO contrast medium [SPIO-liver uptake and distribution alterations (SPIO-LUDA)] could lead to diagnostic errors at SPIO-MRI.

MATERIALS AND METHODS

We used DC-MRI to study 67 patients suffering from hepatic cirrhosis and on a waiting list for liver transplant. The study was performed with a 1.5-Tesla device and characterised by three phases: the first phase without contrast material (unenhanced MRI), the second after the administration of ferumoxides (SPIO-MRI), and the third, a double-contrast study following the injection of a bolus of paramagnetic contrast material (DC-MRI). The sensitivity of unenhanced MRI, SPIO-MRI and DC-MRI in identifying and characterising hepatic focal lesions was assessed, together with the diagnostic increment of one technique with respect to the others. The gold standard was histological confirmation in 38 cases and clinical-radiological follow-up in all cases. Liver function, kidney function, blood tests and urinalysis were performed in all patients 24-48 h before and after the MRI examination.

RESULTS

In 14/67 cases (20.8%), SPIO-LUDA were present, which posed a limitation to the SPIO-MRI examination. Focal lesions were absent in 44 patients, and the action of the ferumoxides was reduced by the presence of SPIO-LUDA in nine cases. There were five cases of confluent fibrosis, two of decompensated cirrhosis, one of vascular thrombosis, and one of scarring in a patient who had undergone hepatic resection for hepatocellular carcinoma (HCC). In all these cases, completion of the MR examination with the DC technique clarified the MR picture, confirming the absence of focal lesions. Twenty-three patients had a total of 68 lesions, which consisted of 37 dysplastic nodules (DN), 19 HCC nodules, two relapses of HCC following chemoembolisation, two HCC associated with portal thrombosis, one cancer-cirrhosis, two angiomas and five small cysts. SPIO-LUDA were present in five patients, thus limiting the identification, characterisation or assessment of the real size of the lesions. SPIO-LUDA were the result of vascular thrombosis in one case and fibrosis in four cases. In all of these cases, DC-MRI proved useful for diagnosis. The sensitivity of unenhanced MRI, SPIO-MRI and DC-MRI for lesion detection was 57.3%, 67.6% and 75%, respectively. The results obtained in the characterisation of the lesions were 20.5%, 63.2% and 73.5% for unenhanced MRI, SPIO-MRI and DC-MRI, respectively. The diagnostic increment of SPIO-MRI over unenhanced MRI for lesion identification and characterisation was 9% and 42.7%, respectively, whereas the diagnostic increment of DC-MRI over SPIO-MRI was 7.4% and 10.3%, respectively.

CONCLUSIONS

In our study, the combined use of two contrast agents, negative and positive, provided greater diagnostic confidence and caused no side effects in the patients.

Musca domestica is not a vector of Thelazia callipaeda in experimental or natural conditions

Thelazia callipaeda Railliet and Henry (Spirurida: Thelaziidae), commonly called oriental eyeworm for its widespread presence in the Far East, has been recently found to affect dogs, cats and foxes in northern and southern Italy. Although the biology of T. callipaeda in the definitive hosts has been recently investigated, many doubts still remain about its biology in insect vectors. It has been suggested that more than one species of Diptera, namely Musca domestica Linnaeus (Diptera: Muscidae) and Amiota okadai Maca (Diptera: Drosophilidae), may be involved in the transmission of T. callipaeda in China. The aim of the work described here was to verify the role of M. domestica as a vector of T. callipaeda both in experimental and natural conditions. A total of 310 m. domestica (Group 1) were put in a cage and allowed to feed for 14 days around the eyes of a dog naturally infected by T. callipaeda. Ten flies were collected daily for 14 days. A total of 149 houseflies (Group 2) were fed with T. callipaeda first stage larvae (L1) and dissected at 1, 2 and 7 days post-infection. From June to August 2003, flies were netted (Group 3) in two different sites every 10 days both from the environment and directly from the periocular region of dogs affected by thelaziosis. Musca flies were examined for eyeworms by dissection and visual inspection of house flies (Groups 1 and 2) and using a molecular approach (Groups 1-3) via a specific amplification of the ribosomal internal transcribed spacer 1 (ITS1) sequence of T. callipaeda. On the whole, 180 pools of M. domestica flies were processed molecularly and all the experimentally infected flies (Groups 1 and 2) were found to be negative both at the visual dissection and at the molecular assay. Similarly, the 234 M. domestica collected from Group 3 were negative for T. callipaeda. The results clearly suggest that M. domestica is unlikely to act as a vector of T. callipaeda in southern Europe, in contrast with a single previous report.

Morphological variability and genetic identity in Rhinoestrus spp. causing horse nasal myiasis

Larvae of Rhinoestrus purpureus (Brauer) and Rhinoestrus usbekistanicus Gan (Diptera: Oestridae) cause nasal myiases of equids. During a recent epidemiological survey in southern Italy some morphological and taxonomical doubts arose concerning the identification of Rhinoestrus third stage larvae on the basis of the features of the posterior spiracles and the distribution of dorsal spines on the third segment. Four different morphotypes were retrieved: R. usbekistanicus-like, R. purpureus-like and two morphotypes with shared features. The genes encoding for the mitochondrial cytochrome oxidase I (COI) and for the ribosomal subunits 16S and 28S of the four morphotypes of Rhinoestrus were investigated to determine whether they belonged to a single taxon or they displayed genetic differences indicative of more than one species. The three genes showed a very low level of sequence variation (COI 0-0.43%, 16S 0-1.45%, 28S 0-0.23%) falling within the intraspecific ranges previously described for Oestridae species. Finally, the peritreme features and the spinulation of the third segment of the four morphotypes examined could not be used to differentiate the two species.

Cross-sectional survey of ticks (Acari: Ixodidae) in sheep from an area of the southern Italian Apennines

A cross-sectional survey of ticks was conducted on 197 ovine farms with animals pasturing in an area (3971 km2) of the southern Italian Apennines. The farms were selected to be uniformly distributed throughout the study area using Geographical Information System (GIS). Ticks were collected from 309 (31.4%) out of the 985 sheep sampled, belonging to 92 (46.7%) out of the 197 farms included in the study. The following tick species were found (farm prevalence): Dermacentor marginatus (37.6%), Haemaphysalis punctata (29.4%), H. sulcata (2.5%), H. parva (2.0%). H. inermis (0.5%), Ixodes gibbosus (2.0%), I. ricinus (0.5%), Rhipicephalus sanguineus group (1.0%), and R. bursa (0.5%). A point distribution map (PDM) was drawn by GIS in order to display the distribution of each tick genus in the study area. The general trends of the PDM show that Dermacentor marginatus and Haemaphysalis spp. were widely and homogeneously spread throughout the study area, whereas Rhipicephalus spp. and Ixodes spp. were present only in a few concentrated zones of the study area in accordance to their biological and ecological characteristics.

Mechanism of protection against carbon tetrachloride toxicity. II. Lethality in rats fed a polyunsaturated fatty acid deficient diet

A PUFA-deficient diet causes deficiency symptoms and alters the fatty acid pattern in liver microsomal lipids. However, CCl4 lethality and sleeping time remain unchanged while the hepatic level of cytochrome P450 is only slightly lowered by the dietary regimen. In accordance, the amplitude of double bond shifting in microsomal lipids is far from being depressed in animals deprived of the peroxidative substrate. In fact, the experimental treatment does not impair intestinal absorption, liver uptake and metabolism of CCl4 given orally. Finally, both in vitro and in vivo peroxidative challenge of arachidonic acid content in hepatic microsomes causes comparable alterations of this parameter, whatever the initial fatty acid pattern following the dietary regimen. These findings provide evidence excluding an influence of the fatty acid composition of the diet on the severity of damages due to halogen-alkane exposure.

Mechanism of protection against carbon tetrachloride toxicity. I. Prevention of lethal effects by partial surgical hepatectomy

Both partial surgical hepatectomy and a challenge with a small dose of CCl4 depress the metabolism of xenobiotics in the liver. In fact, hepatocytes become provided with metabolic activity rates which are peculiar of either embryo or newborn rat liver. These experiments have shown that partial surgical hepatectomy prevents rats from death caused by otherwise lethal doses of CCl4. At the same time, sham-operated animals survive to a limited extent after a large dose of the halogen compound. Investigations carried out on the metabolic efficiency of liver microsomes, both in vito and in vivo, clearly demonstrate that the preventive effect against CCl4 depends mainly on the impaired metabolic activity of endoplasmic reticulum.