Review of wheat improvement for waterlogging tolerance in Australia and India: the importance of anaerobiosis and element toxicities associated with different soils.

BACKGROUND AND AIMS: The lack of knowledge about key traits in field environments is a major constraint to germplasm improvement and crop management because waterlogging-prone environments are highly diverse and complex, and the mechanisms of tolerance to waterlogging include a large range of traits. A model is proposed that waterlogging tolerance is a product of tolerance to anaerobiosis and high microelement concentrations. This is further evaluated with the aim of prioritizing traits required for waterlogging tolerance of wheat in the field. METHODS: Waterlogging tolerance mechanisms of wheat are evaluated in a range of diverse environments through a review of past research in Australia and India; this includes selected soils and plant data, including plant growth under waterlogged and drained conditions in different environments. Measurements focus on changes in redox potential and concentrations of diverse elements in soils and plants during waterlogging. KEY RESULTS: (a) Waterlogging tolerance of wheat in one location often does not relate to another, and (b) element toxicities are often a major constraint in waterlogged environments. Important element toxicities in different soils during waterlogging include Mn, Fe, Na, Al and B. This is the first time that Al and B toxicities have been indicated for wheat in waterlogged soils in India. These results support and extend the well-known interactions of salinity/Na and waterlogging/hypoxia tolerance. CONCLUSIONS: Diverse element toxicities (or deficiencies) that are exacerbated during waterlogging are proposed as a major reason why waterlogging tolerance at one site is often not replicated at another. Recommendations for germplasm improvement for waterlogging tolerance include use of inductively coupled plasma analyses of soils and plants.

Platelet membrane CD154 and sCD154 in progressive peripheral arterial disease: a pilot study.

OBJECTIVE: The expression and potential role of platelet membrane CD154 and sCD154 in atherosclerosis was investigated in patients with peripheral arterial disease. METHODS: This prospective observational study measured the expression of platelet-bound CD154 and soluble CD154 (sCD154) in 39 patients with critical limb ischaemia (CLI, n=15), stable intermittent claudication (SIC, n=12) and age-matched controls (AMC, n=12). Basal and agonist-stimulated CD154, P-selectin expression and fibrinogen binding was measured by whole blood flow cytometry, while sCD154 was measured in paired plasma samples by ELISA. RESULTS: Basal expression of CD154 on the platelet surface was enhanced in both groups of patients with peripheral arterial disease. However, the critical limb ischaemics showed the highest level of basal expression 0.7+/-0.3 [median+/-IQR] and was significantly increased compared to both stable intermittent claudicants and age-matched controls (P<0.001). On agonist stimulation with either ADP or thrombin critical limb ischaemics demonstrated greater platelet reactivity and propensity to express CD154 compared to age-matched controls (P<0.05). Confirmation of the cellular expression of CD154 results was obtained by measuring sCD154 concentrations in autologous plasma samples. Here plasma levels of sCD154 in critical limb ischaemics were significantly greater than both stable intermittent claudicants and age-matched controls (P<0.005). CONCLUSIONS: Enhanced basal platelet expression and increased propensity to express CD154 and sCD154 in critical limb ischaemics compared to both controls and patients with stable intermittent claudication support evidence for the role of CD154 in atherogenesis and suggest a novel function in progressive and acute peripheral arterial disease.

Patterns of peroxidative ethane emission from submerged rice seedlings indicate that damage from reactive oxygen species takes place during submergence and is not necessarily a post-anoxic phenomenon.

Using ethane as a marker for peroxidative damage to membranes by reactive oxygen species (ROS) we examined the injury of rice seedlings during submergence in the dark. It is often expressed that membrane injury from ROS is a post-submergence phenomenon occurring when oxygen is re-introduced after submergence-induced anoxia. We found that ethane production, from rice seedlings submerged for 24-72 h, was stimulated to 4-37 nl gFW(-1), indicating underwater membrane peroxidation. When examined a week later the seedlings were damaged or had died. On de-submergence in air, ethane production rates rose sharply, but fell back to less than 0.1 nl gFW(-1) h(-1) after 2 h. We compared submergence-susceptible and submergence-tolerant cultivars, submergence starting in the morning (more damage) and in the afternoon (less damage) and investigated different submergence durations. The seedlings showed extensive fatality whenever total ethane emission exceeded about 15 nl gFW(-1). Smaller amounts of ethane emission were linked to less extensive injury to leaves. Partial oxygen shortage (O(2) levels <1%) imposed for 2 h in gas phase mixtures also stimulated ethane production. In contrast, seedlings under anaerobic gas phase conditions produced no ethane until re-aerated: then a small peak was observed followed by a low, steady ethane production. We conclude that damage during submergence is not associated with extensive anoxia. Instead, injury is linked to membrane peroxidation in seedlings that are partially oxygen deficient while submerged. On return to air, further peroxidation is suppressed within about 2 h indicating effective control of ROS production not evident during submergence itself.

Kinetics of ethanol and acetaldehyde release suggest a role for acetaldehyde production in tolerance of rice seedlings to micro-aerobic conditions.

BACKGROUND AND AIMS: This paper examines the basis of the greater tolerance of an indica rice cultivar FR13A to complete submergence compared with relatively intolerant japonica rice CT6241. We study whether this superior tolerance is related to its greater tolerance to O2 shortage and to an ability to run a more favourable rate of alcoholic fermentation during and after O2 deprivation. METHODS Fermentation products were analysed using sensitive laser-based photoacoustics at high time resolution to establish patterns and rates of ethanol and acetaldehyde emission by intact rice seedlings exposed to micro-aerobic (0.05-0.5 % O2) or zero O2 supply, and also during their return to air. Oxygen and CO2 emission or uptake was also quantified. KEY RESULTS: In the dark, no acetaldehyde and ethanol emission was observed until external O2 concentration in a gas phase decreased to

CT appearance of abdominal thorotrast deposition and Thorotrast-induced angiosarcoma of the liver.

Although the clinical and radiographic manifestations of Thorotrast and its complications have been described, the computed tomographic (CT) appearance of Thorotrast deposition in the abdomen is less well known. Thorotrast produces a characteristic opacification of the liver, spleen, and abdominal lymph nodes. We report two cases of patients with Thorotrast-induced angiosarcoma of the liver detected by CT. Computed tomography in both cases demonstrated space-occupying lesions in the liver, which were readily detectable because of distortion of the Thorotrast-produced opacification.

Comparison of real-time and static-mode gray-scale ultrasonography in the diagnosis of cholelithiasis.

Real-time and conventional articulated-arm gray-scale static-mode scanning were performed on 100 patients in a prospective study to determine the complementary or duplicative roles of these two ultrasound modalities in the confirmation of clinically suspected cholelithiasis. Twenty-five abnormal findings were documented ultrasonographically, including 21 cases of cholelithiasis (12 confirmed by oral cholecystography and/or surgery), two cases of biliary sludge, one case of a gallbladder polyp, and one case of a probable blood clot. There was no instance of gallbladder lumen nonvisualization. Except in one case (that of a 420-pound patient), real-time ultrasonography documented all the gallbladder abnormalities shown by the articulated-arm static scans. In two cases, one corroborated by oral cholecystography, cholelithiasis was documented by real-time and not by static-mode ultrasonography. In most cases, real-time ultrasonography can be used to document the presence of cholelithiasis and obviate the need for conventional articulated-arm static-mode scanning.

Computed tomography of pleural disease.

The computed tomography (CT) scans of 65 cases with histologic and clinical evidence of pleural disease were reviewed. The studies were analyzed according to the following CT features of the lesions: attenuation coefficient, contour, angle of interface with the adjacent pleura, and relationship to the adjacent lung, bone, and extrapleural tissues. The CT feature most helpful in detecting pleural involvement was the angle formed by the interface of the lesion with the adjacent pleura. An obtuse or tapering angle was seen in lesions involving the pleura. The other CT features are useful in identifying the site of origin and the specific nature of a lesion.

Review. In utero sonographic diagnosis of fetal cerebral anomalies.

Obstetric sonography can be used to diagnose anomalies in the fetal brain. Cystic masses in the fetal brain may be due to hydrocephalus, hydranencephaly, holoprosencephaly, or arachnoid cysts. The relations of the falx cerebrum, ventricular system, and cerebral convexities are essential in distinguishing among these anomalies. Anencephaly and encephaloceles can also be detected by sonography. A review of the literature and experience with 10 cases is discussed.

CT appearance of focal fatty infiltration of the liver.

Focal fatty infiltration of the liver is an entity that may be confused with liver metastasis on computed tomography (CT). The imaging results and medical records of 16 patients with CT appearance suggestive of focal fatty liver were reviewed, three of whom had the simultaneous presence of metastatic liver disease. Focal fatty liver often has a distinctive appearance with CT, usually with a nonspherical shape, absence of mass effect, and a density close to water. Liver metastases are usually round or oval, and unless cystic or necrotic, they have CT attenuation values closer to normal liver parenchyma than water. A radionuclide liver scan almost always resolves any confusion about the differential diagnosis of focal fatty liver: a well defined focus of photon deficiency is due to neoplasm rather than focal fatty infiltration. Sonography sometimes helps to confirm the CT impression, but may be misleading if the diagnosis of focal or diffuse fatty infiltration is not suspected before the examination.

Parapelvic cysts: appearance on CT and sonography.

The computed tomographic (CT) and sonographic appearance of 16 patients with parapelvic cysts were retrospectively reviewed. CT revealed a water-density renal hilar mass that did not fill with contrast material after intravenous injection. Sonography demonstrated a cystic renal hilar mass with echogenic walls that did not communicate with the collecting system. The differential diagnosis of renal hilar masses as seen by CT and sonography is discussed.

Extracranial cribside sonography in infants.

In 29 real-time ultrasonic studies of infants in the intensive care nursery, the technique either accurately diagnosed or led directly to the correct diagnosis in 27 (93%). Twenty-four of these infants had suspected abnormality in the abdomen or pelvis, three had congestive heart failure and bruits, one had respiratory distress and an opacified hemithorax on chest roentgenogram, and one was a child with ambiguous genitalia in whom sonography identified a uterus. We suggest that portable, real-time ultrasonography is an ideal modality with which to study seriously ill infants whose medical condition precludes transport to the radiology department.

Dynamic aspects of alcoholic fermentation of rice seedlings in response to anaerobiosis and to complete submergence: relationship to submergence tolerance.

Rice plants are severely damaged by complete submergence. This is a problem in rice farming and could be the result, in part, of tissue anoxia imposed by a reduced availability of oxygen. To investigate this possibility we monitored alcoholic fermentation products as markers for tissue anaerobiosis using sensitive laser-based spectroscopy able to sense ethanol and acetaldehyde down to 3 nl l(-1) and 0.1 nl l(-1), respectively. Acetaldehyde emission began within 0.5 h of imposing an oxygen-free gas phase environment followed closely by ethanol. As treatment progressed, ethanol output increased and came to exceed acetaldehyde emission as this stabilized considerably after approx. 3 h. On re-entry of air, a sharp post-anaerobic peak of acetaldehyde production was observed. This was found to be diagnostic of a preceding anoxic episode of 0.5 h or more. When anaerobiosis was lengthened by up to 14 h, the size of the post-anaerobic acetaldehyde outburst increased. After de-submergence from oxygen-free water, a similarly strong but slower post-anaerobic acetaldehyde upsurge was seen, which was accompanied by an increase in ethanol emission. Light almost, but not completely, eliminated fermentation in anaerobic surroundings and also the post-anaerobic or post-submergence peaks in acetaldehyde production. All photosynthetically generated oxygen was consumed within the plant. There was no substantial difference in acetaldehyde and ethanol output between FR13A and the less submergence-tolerant line CT6241 under any submergence treatment. In some circumstances, submergence damaged CT6241 more than FR13A even in the absence of vigorous fermentation. We conclude that oxygen deprivation may not always determine the extent of damage caused to rice plants by submergence under natural conditions.

CT detection of intraosseous gas: a new sign of osteomyelitis.

In three patients the diagnosis of osteomyelitis was made when computed tomography (CT) demonstrated gas within the medullary cavity of the involved bone. The diagnosis was clinically unsuspected in two of the patients before the CT examination, and none showed bone abnormalities on plain radiographs. Two patients had evidence of infection of the deep soft tissues adjacent to bone, and the third developed the lesion in an allograft. In all three patients CT detection of intraosseous gas resulted in significant alteration of patient management.

CT demonstration of subcutaneous venous collaterals.

Subcutaneous collateral veins were identified by computed tomography (CT) in 12 patients. These were seen as enhancing round or tubular structures surrounded by subcutaneous fat, and most were associated with occlusion of a major vein in the abdomen or thorax. The CT appearance of deep vein occlusions included an intraluminal thrombus with an enhancing rim, a mass replacing the nonvisualized vein and distortion of the vein by an adjacent mass. The subcutaneous fat was examined on the CT scans of 50 patients not suspected of having deep venous occlusions. The appearance of normal subcutaneous structures and the differential diagnosis are discussed.

Age-related changes in the thymus gland: CT-pathologic correlation.

Recent reports suggest that computed tomography (CT) is useful for thymoma detection in patients with myasthenia gravis. However, that usefulness may be conditioned by the state of the normal thymus. To examine this concept, the CT findings in 64 consecutive patients with histologic confirmation of thymic status after thymectomy or thymic biopsy during mediastinal exploration were reviewed. The normal thymus has a bilobed, arrowhead-shaped cross section at all ages, with gradual focal or diffuse fatty infiltration of the parenchyma usually occurring between 20 and 40 years of age. A thymoma is usually a spherical or oval mass, often producing a focal, distinct bulge in the adjacent pleural reflection. The differentiation of thymoma from normal thymus should be possible in most patients if age-related changes in the normal gland are appreciated.

Thymoma detection by mediastinal CT: patient with myasthenia gravis.

The precise role of computed tomography (CT) in evaluating the mediastinum for thymomas in patients with myasthenia gravis is not defined. The only published CT accuracy assessment reports a false-positive rate of 90%. Mediastinal CT was performed in 23 consecutive unselected patients with myasthenia gravis who underwent thymectomy independent of their neurologic status or diagnostic imaging results. Four patients had discrete thymomas; all were detected by CT. Conventional chest radiography and tomography were positive in three and falsely negative in one. In the remaining 19 patients with a normal or atrophic thymus or microscopic hyperplasia, CT was falsely positive in two; conventional chest radiography and tomography were falsely positive in three. Mediastinal CT is an accurate technique for evaluation of thymoma in patients with myasthenia gravis.

Volume determinations using computed tomography.

Computed tomography potentially offers the most accurate noninvasive means of estimating in vivo volumes. Contiguous 1-cm-thick CT scans were obtained through phantoms, dog kidneys in vivo, and human spleens before splenectomy. Cross-sectional areas were calculated for each individual scan and volumes then determined with each of four mathematical integration techniques. Volume estimations were compared to volumes determined by water displacement. The simplest, most practical means of calculating volumes, using the summation-of-areas technique with scans obtained at 2 cm intervals, was similar in accuracy to more complex methods. The mean percentage error of volume calculations using the sum-of-areas technique was 4.95% for five immobile phantoms, 3.86% for eight dog kidneys, 3.59% for eight human spleens in vivo at 1 cm scan spacing, and 3.65% for the same human spleens at 2 cm scan spacings. Difficulties in visual recognition and manual tracking of object boundaries seem to be more significant sources of error than patient-related factors.