Fast formation of supergene Mn oxides/hydroxides under acidic conditions in the oxic/anoxic transition zone of a shallow aquifer.

Extensive uranium mining in the former German Democratic Republic (GDR) in eastern Thuringia and Saxony took place during the period of 1946-1990. During mining activities, pelitic sediments rich in organic carbon and uranium were processed and exposed to oxygen. Subsequent pyrite oxidation and acidic leaching lead to partial contamination of the area with heavy metals and acid mine drainage (AMD) even few years after completion of remediation. One of those areas is the former heap Gessen (Ronneburg, Germany) were the residual contamination can be found 10 m under the base of the former heap containing partly permeable drainage channels. Actually, in such a system, a rapid but locally restricted mineralization of Mn oxides takes place under acidic conditions. This formation can be classified as a natural attenuation process as certain heavy metals, e.g., Cd (up to 6 µg/g), Ni (up to 311 µg/g), Co (up to 133 µg/g), and Zn (up to 104 µg/g) are bound to this phases. The secondary minerals occur as colored layers close to the shallow aquifer in glacial sediments and could be identified as birnessite and todorokite as Mn phase. The thermodynamic model shows that even small changes in the system are sufficient to shift either the pH or the Eh in the direction of stable Mn oxide phases in this acidic system. As a consequence of 9-15-year-long formation process (or even less), the supergene mineralization provides a cost-efficient contribution for remediation (natural attenuation) strategies of residual with heavy metals (e.g., Cd, Co, Ni, Zn) contaminated substrates.

Siderophores mediate reduced and increased uptake of cadmium by Streptomyces tendae F4 and sunflower (Helianthus annuus), respectively.

AIMS: As a toxic metal, cadmium (Cd) affects microbial and plant metabolic processes, thereby potentially reducing the efficiency of microbe or plant-mediated remediation of Cd-polluted soil. The role of siderophores produced by Streptomyces tendae F4 in the uptake of Cd by bacteria and plant was investigated to gain insight into the influence of siderophores on Cd availability to micro-organisms and plants. METHODS AND RESULTS: The bacterium was cultured under siderophore-inducing conditions in the presence of Cd. The kinetics of siderophore production and identification of the siderophores and their metal-bound forms were performed using electrospray ionization mass spectrometry. Inductively coupled plasma spectroscopy was used to measure iron (Fe) and Cd contents in the bacterium and in sunflower plant grown in Cd-amended soil. Siderophores significantly reduced the Cd uptake by the bacterium, while supplying it with iron. Bacterial culture filtrates containing three hydroxamate siderophores secreted by S. tendae F4 significantly promoted plant growth and enhanced uptake of Cd and Fe by the plant, relative to the control. Furthermore, application of siderophores caused slightly more Cd, but similar Fe uptake, compared with EDTA. Bioinoculation with Streptomyces caused a dramatic increase in plant Fe content, but resulted only in slight increase in plant Cd content. CONCLUSION: It is concluded that siderophores can help reduce toxic metal uptake in bacteria, while simultaneously facilitating the uptake of such metals by plants. Also, EDTA is not superior to hydroxamate siderophores in terms of metal solubilization for plant uptake. SIGNIFICANCE AND IMPACT OF THE STUDY: The study showed that microbial processes could indirectly influence the availability and amount of toxic metals taken up from the rhizosphere of plants. Furthermore, although EDTA is used for chelator-enhanced phytoremediation, microbial siderophores would be ideal for this purpose.

Ehrlichiosis: findings on chest radiographs in three pediatric patients.

OBJECTIVES: Ehrlichiosis is a newly recognized tick-borne infection affecting both children and adults. The disease is usually mild, with flulike symptoms, but can be fatal. We present the chest radiographs and, in one case, the chest CT scan of all recognized pediatric cases of ehrlichiosis to date from our institution. CONCLUSION: Ehrlichiosis should be included in the differential diagnosis of acutely ill pediatric patients with a history of possible tick exposure and radiographic patterns of interstitial prominence, alveolar opacities, or consolidation that may be associated with pleural effusion.

Radiologic staging of thoracoabdominal tumors in childhood.

Thoracoabdominal tumors of childhood include a pathologically diverse spectrum of neoplasms. Improved survival for many of these once lethal malignancies reflects current multimodality approaches to treatment based on the combined experience of specific tumor study groups. The choice of surgery, chemotherapy, and/or radiation depend on accurate clinical and radiologic staging based on determination of tumor extent and the feasibility of surgical resection. Advanced cross-sectional and scintigraphic imaging techniques have enhanced the accuracy of radiologic assessment and staging. Established pathologic patterns of local extension and more distant dissemination, as well as the relative sensitivity and specificity of applicable imaging modalities determine radiologic approaches to radiologic staging of specific neoplasms.

Practical approaches to pediatric gastrointestinal radiology.

Radiologic evaluation of the pediatric gastrointestinal tract requires knowledge of the specific problems acutely afflicting the gastrointestinal tract in children and the specialized approaches required for accurate radiologic diagnosis. Efficacious radiologic evaluation and accurate diagnosis are possible only when the radiologist is aware of the presence and significance of clinical findings. The radiologist must take an active role in formulating a presumptive diagnosis and determining the best course of radiologic examination. Careful correlation of clinical and radiologic findings is necessary to assure accurate diagnosis and appropriate treatment.

Bilateral nasolacrimal duct mucocele, a rare cause of respiratory distress: CT findings in two newborns.

Two newborns presented with severe respiratory distress caused by nasal obstruction. CT showed bilateral soft-tissue masses located under the inferior turbinates at the level of the inferior meatuses. Histologic examination showed the lesions to be compatible with nasolacrimal mucoceles. The embryology and radiographic features of this rare anomaly are discussed.

Long-term outcome of pediatric sarcoidosis with emphasis on pulmonary status.

Sixty-one pediatric and adolescent patients (age < or = 16 years) with sarcoidosis proved by biopsy specimen were identified during the period 1957 to 1976; 19 patients with elapsed time from diagnosis of 8 to 35 years (mean, 21 years) were reexamined in 1985. Age at onset of disease ranged from 4 to 16 years (mean, 12.5 years). Sex distribution was equal; 68 percent of individuals were black. At follow-up, clinical evaluation, chest roentgenograms, pulmonary function tests, electrocardiograms (ECGs), echocardiograms (ECHO), and angiotensin-converting enzyme (ACE) activity were performed on each subject. In addition, complete blood cell counts, erythrocyte sedimentation rates, serum calcium, immunoglobulin levels, B- and T-cell enumerations, and intradermal skin tests for delayed hypersensitivity were also obtained. Although all initial pediatric chest roentgenograms were abnormal, at follow-up only 37 percent were abnormal. Pulmonary function test results were available for ten children, and 90 percent were decreased. In 1985, 68 percent of the adults had abnormal lung function; furthermore, eight patients had reduced diffusing capacities, one had hypoxemia, and two had elevated ACE activity. Specific abnormalities were noted on two ECGs and 12 ECHOs. One individual had an elevated sedimentation rate, while another had an increased serum calcium level. Six patients had elevated IgA values, two had elevated IgM values, and two had depressed IgM values; IgG values were normal in all subjects. B- and T-cell percentages were unremarkable in all patients tested. Four individuals were anergic to skin test antigens. Long-term pulmonary morbidity was observed in four patients; in addition, one of these and four others suffered nonpulmonary sequelae. These results are in agreement with those of other investigators, but insufficient data still exist on the long-term effects of sarcoidosis on the pediatric host.

Acquired lobar emphysema (overinflation): clinical and pathological evaluation of infants requiring lobectomy.

Acquired lobar "emphysema" (overinflation) (ALE) is an increasingly recognized complication of advanced bronchopulmonary dysplasia (BPD). To refine current concepts regarding patient management and pathogenesis, we examined clinical and pathological features of six infants with ALE who did not have obstructing intraluminal lesions and who underwent lobectomy after failing nonoperative management. All had severe neonatal respiratory distress and required prolonged ventilatory support (average, 2 months) with peak inspiratory pressures greater than 30 mm Hg and 100% oxygen. ALE developed between 3 weeks and 20 months of age (median, 5 months), with lobar hyperinflation, atelectasis, and mediastinal shift. Selective bronchial intubation provided only transient benefit. Videobronchoscopy demonstrated no intraluminal obstructing lesions in five patients. In one child, ALE became clinically apparent only after laser excision of an endobronchial cicatrix. All infants had bronchomalacia with the involved lobar bronchus being most severely affected. Ventilation-perfusion scans demonstrated severe impairment of both ventilation and perfusion in the involved lobes. The decision to perform lobectomy was based on clinical parameters and failure of non-operative management. After lobectomy, all children dramatically improved. However, only three of six were alive 2 to 3 years later; one infant died of unrelated causes at 6 weeks; and two died of progressive respiratory insufficiency 13 and 24 months postlobectomy. Microscopic evaluation of the lung demonstrated findings of late-stage BPD with peribronchial and interstitial fibrosis, parenchymal overinflation, and alveolar septal disruption.(ABSTRACT TRUNCATED AT 250 WORDS)

Coexisting endogenous lipoid pneumonia, cholesterol granulomas, and pulmonary alveolar proteinosis in a pediatric population: a clinical, radiographic, and pathologic correlation.

Benign pulmonary diseases that have been associated with the accumulation of endogenous lipids within the alveoli, bronchioles, and interstitial tissues include endogenous lipoid pneumonia (ELP), pulmonary alveolar proteinosis (PAP), pulmonary interstitial and intra-alveolar cholesterol granulomas (PICG), various xanthomatous lesions, and malakoplakia. In ELP, fat-filled finely vacuolated macrophages fill the alveoli. In PAP, the aveoli become filled with cholesterol and periodic acid-Schiff (PAS)-positive acellular debris. In PICG, cholesterol esters are released from degenerating macrophages and, as organization occurs, the cholesterol is deposited in the form of acicular clefts within the interstitium. These morphologically distinct presentations of endogenous lipid deposition within the lung have long been thought to represent unique disease processes but several authors now postulate a possible relationship between these entities. We report here on the clinical, radiographic, and morphologic findings in eight pediatric patients with diverse primary disease processes who were subsequently found to have varying and often coexisting degrees of ELP, PAP, and PICG.

Diagnostic imaging of mediastinal masses in children.

Mediastinal masses are the most common thoracic masses in children. The encyclopedic list of diagnostic considerations can be distilled into a concise and practical differential diagnosis based on the location of the mass and the established prevalence of various tumors and pseudotumors in the mediastinal compartments. Malignant lymphoma, benign thymic enlargement, teratomas, foregut cysts, and neurogenic tumors make up 80% of mediastinal masses in children. Continuing advances in imaging technology have altered traditional approaches to the evaluation and diagnosis of mediastinal masses in children. Plain chest radiography remains the basic imaging examination to define location and morphology. Cross-sectional imaging subsequently clarifies the morphology and extent of the mass. In general, CT is the primary cross-sectional imaging procedure in the evaluation of most mediastinal masses in children. Exceptions to this rule include MR in children with posterior mediastinal masses or suspected vascular lesions: in such cases, MR imaging is the preferred initial postradiographic examination. Sonographic examination may be diagnostic in foregut cysts and some other mediastinal masses. Gallium-67 scintigraphy has an emerging role in management of malignant lymphoma.

Radiographic manifestations of congenital anomalies affecting the airway.

Congenital anomalies of the airway are generally uncommon, but a vast array of possibilities exists. Some present life-threatening emergencies at birth, and others go undiagnosed for years. Clinical symptoms are often nonspecific, and radiographic evaluation is frequently requested to localize and characterize the lesion before endoscopy, surgery, or medical management. The most common intrinsic congenital anomalies causing airway compromise in infants include choanal atresia, mandibular hypoplasia, laryngomalacia, vocal cord paralysis, and congenital subglottic stenosis. The radiologist must be on the alert for unsuspected additional anomalies involving the airway, lungs, and esophagus, which occur with relative frequency. Numerous extrinsic congenital masses of the head, neck, and mediastinum may compromise the airway. Hemangiomas, lymphangiomas, and teratomas are more likely to be noted at birth, whereas branchial cleft cysts, thyroglossal duct anomalies, and dermoid cysts frequently present later. Mass location and radiographic characteristics usually allow accurate preoperative diagnosis. Intracranial involvement by nasal or nasopharyngeal masses, intrathoracic involvement by lower neck mass, and intraspinal involvement by posterior neck mass must always be sought for radiographically. Persistence of respiratory symptoms after removal of such masses is not uncommon because tracheal deformity and laxity may take months or years to resolve. Recent advances in cine CT and MR imaging promise to improve imaging of the airway in general and in the pediatric population in particular. Significant limitations in imaging of the pediatric larynx remain. As a result, endoscopy continues to be the primary diagnostic tool for airway anomalies of this region.

Radiologic imaging of inflicted injury in the child abuse syndrome.

Injuries associated with child abuse may involve any anatomic focus and organ system. Although many if not most of the injuries associated with physical abuse cannot serve as definitive evidence of maltreatment, awareness of patterns of injuries in abused infants and children initially may serve to identify potential victims of abuse and stimulate more thorough clinical and radiologic investigation. It is essential that less familiar intracranial and abdominal injuries be thoroughly evaluated for possible abuse when circumstances suggest maltreatment, or no plausible explanation is given for radiologic findings.

Air embolism with survival in a neonate.

Air embolism in neonates is usually fatal. We describe an infant who survived and discuss the pathogenesis and management of this condition.

Nodular form of bleomycin-related pulmonary injury in patients with osteogenic sarcoma.

Bleomycin (BLEO), an antitumor antibiotic effective against a variety of malignancies, has been associated classically with a pulmonary toxic reaction producing diffuse interstitial fibrosis. However, BLEO-related pulmonary nodules have been reported recently, mostly in children and young adults treated for germ cell tumors. A different, apparent hypersensitivity reaction with prominent eosinophilic infiltrates has been seen in other patients. This report details the clinical history, radiographic features, and histopathologic condition of three patients with osteogenic sarcoma in whom pulmonary nodules developed during the course of their multiagent, BLEO-containing chemotherapy. The predominant histopathologic lesion was bronchiolitis obliterans-organizing pneumonia (BOOP); one patient had a significant eosinophilic infiltrate also. Pulmonary lesions developed in all of these patients after relatively low doses of BLEO (less than 200 mg). All of these patients underwent open lung biopsy to establish the diagnosis. Reported cases of BLEO-induced pulmonary injury other than diffuse fibrosis are reviewed and comparisons are made with those in the current report. Also, suggestions are made for the management of these patients.

Rational use of diagnostic imaging in paediatrics. The report of a World Health Organization Study Group.

The World Health Organization (WHO) is the agency of the United Nations with primary responsibility for international health matters and public health. Through the exchange of the knowledge and experience of health professionals from 165 nations WHO promotes comprehensive health services worldwide. As a part of this effort WHO has in recent years been concerned with improving the availability and utilization of diagnostic imaging, especially as it relates to health services in developing countries. Having devised and specified suitable basic radiographic equipment (the WHO BRS) a WHO Scientific Group was convened in 1982 to study the utilization of radiographic procedures and to to recommend their more efficacious and rational use. Then in 1984, recognizing the implications of newer imaging technology on world health, a second WHO Scientific Group considered the design, impact and future use of ultrasonography and computed tomography in developing countries. The findings of these scientific groups were published as part of the WHO Technical Report Series which makes available the recommendations of such international groups of experts. Although some of the needs of children were considered in these previous Technical Reports, WHO felt that the size and socioeconomic importance of the paediatric population worldwide warranted a further study and report to address the particular technical and clinical problems of diagnostic imaging in the paediatric age group. Thus a third WHO Scientific Group met in Geneva from 18 to 24 November 1985 to review established practices and experience in paediatric imaging throughout the world; and to recommend rational guidelines for diagnostic imaging for children to age 14 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Ventilator-induced pulmonary pseudocysts in preterm neonates.

Twenty-three pulmonary pseudocysts were identified in 20 preterm neonates undergoing mechanically assisted ventilation. Most of the pseudocysts occurred in a right parahilar location; cysts were either single (13) or multiple/multilocular (10). The pseudocysts persisted from less than 2 days to longer than 3 months (modal duration, 7 days), and they were commonly associated with generalized pulmonary interstitial emphysema (18 of 20), pneumothorax (18 of 20), bronchopulmonary dysplasia (16 of 20), and pneumomediastinum (six of 20). The reason for the predominantly right parahilar location of these pseudocysts remains uncertain. Pulmonary pseudocysts are almost always right-sided and are associated with pulmonary interstitial emphysema and pneumothoraces; complete resolution usually occurs.