Ethiodized oil emulsion 13 in computed tomography of hepatoma.

Six patients with biopsy-proven hepatoma were prospectively evaluated both by conventional computed tomography (CT) and by scans using ethiodized oil emulsion 13 (EOE 13) as a contrast agent. EOE 13 infusion resulted in marked improvement in the demonstration of the neoplasm in all cases and allowed more accurate definition of tumor extent than was possible with standard scanning techniques. In two cases EOE 13 enhancement was essential for complete radiographic depiction of tumor location, size, and extent. EOE 13 also proved to be of considerable value in assessment of therapeutic response in three patients, permitting more objective determination of tumor growth or regression. EOE 13--enhanced CT scanning provides a valuable means of staging patients presenting with hepatoma and is a reliable, accurate means of radiographic follow-up.

The adenylate kinase genes of M. voltae, M. thermolithotrophicus, M. jannaschii, and M. igneus define a new family of adenylate kinases.

The adenylate kinase genes (adkA) were cloned from four closely related methanogenic members of the Archaea: the mesophile Methanococcus voltae (Mv), the thermophile M. thermolithotrophicus (Mt) and the hyperthermophiles M. jannaschii (Mj) and M. igneus (Mi). All four genes encode a protein of 192 amino acids (aa), and the four enzymes were closely related, with 68-81% aa identity in pairwise comparisons. It is anticipated that the enzyme set will provide the basis for studies that can establish the structural basis for ADK thermal stability. Mj and Mi contained a gene homologous to M. vannielii sec Y upstream of adkA, while Mv and Mt contained an unidentified, yet conserved, upstream open reading frame (ORF). Mt, Mj and Mi, but not Mv, contained an unidentified, yet highly conserved, ORF directly downstream of adkA. Based on their size, predicted secondary structure and phylogenetic relation to bacterial and eukaryotic adenylate kinases (ADK), it was concluded that the archaeal adkA genes encoded a unique class of ADK, and suggested that Euryarchaeotal and Crenarchaeotal branches of the Archaea contain separate subclasses of the enzyme.

Cysteinyl-tRNA formation: the last puzzle of aminoacyl-tRNA synthesis.

With the exception of the methanogenic archaea Methanococcus jannaschii and Methanobacterium thermoautotrophicum deltaH, all organisms surveyed contain orthologs of Escherichia coli cysteinyl-tRNA synthetase (CysRS). The characterization of CysRS-encoding (cysS) genes and the demonstration of their ability to complement an E. coli cysSts mutant reveal that Methanococcus maripaludis and Methanosarcina barkeri, two other methanogenic archaea, possess canonical CysRS proteins. A molecular phylogeny inferred from 40 CysRS sequences indicates that the CysRS of M. maripaludis and Methanosarcina spp. are specific relatives of the CysRS of Pyrococcus spp. and Chlamydia, respectively. This result suggests that the CysRS gene was acquired by lateral gene transfer in at least one euryarchaeotic lineage.

Presternal soft tissue calcifications following mediastinal radiotherapy for Hodgkin's disease.

A patient is described in whom dense calcifications developed in the presternal soft tissues of the chest four years after mediastinal radiotherapy. This is believed to represent dystrophic calcification in previously normal but incidentally radiated tissues following standard dose radiotherapy to the mediastinum for stage IIA Hodgkin's disease.

Computed tomography in invasive carcinoma of the cervix: an appraisal.

The clinical staging, computed tomographic scans, and surgical findings in 42 patients with cervical carcinoma were compared prospectively to determine the accuracy and clinical utility of computed tomography in demonstrating extent of disease and involvement of paraaortic lymph nodes. Computed tomography was of limited value in stage IB and IIB tumors, but was comparable in accuracy to clinical examination in the assessment of IIB disease. Computed tomography was of value in radiation therapy and may detect unsuspected bony metastases (stage IVB). Retroperitoneal adenopathy can be detected by computed tomography with an overall accuracy of 83% and a specificity of 86%. Computed tomography is an important adjunct in determining tumor extent in more advanced disease (stages IIIB and IVB) and in detecting paraaortic adenopathy.

Effect of computerized requisition of radiology examinations on the transmission of clinical information.

RATIONALE AND OBJECTIVES: The authors developed a method to evaluate the availability and accuracy of clinical data proffered by clinicians when ordering radiologic examinations with a computer order-entry system. METHODS: Two thousand consecutive clinical indications for a spectrum of pediatric imaging studies were scrutinized for accuracy by means of computerized chart review, verbal communication with clinical attending staff, and reference to surgical and laboratory results. The indications were classified as appropriate, incorrect, misleading, or incomplete. RESULTS: Of the 2,000 stated indications, 1,464 (73%) provided a reasonable, if minimal, amount of clinical information; however, in 376 (19%) cases the diagnosis or proximate indication was incorrect, in 108 (5%) cases the data were incomplete, and in 52 (3%) cases the information was misleading. CONCLUSION: Computer order-entry systems can improve the transmission of clinical information but they allow misinformation to be provided.

Vascular studies in the preoperative evaluation of pituitary adenomas before transsphenoidal surgery.

The transsphenoidal approach is being increasingly utilized in the surgical treatment of pituitary microadenoma. Even with high-resolution and dynamic computed tomography (CT) scanning, subtle vascular anatomic variants and other vascular anomalies involving the parasellar carotid arteries cannot always be clearly defined. Five cases are described in which evaluation by digital intravenous subtraction angiography or standard carotid arteriography provided useful preoperative information before transsphenoidal surgery. The implications of these findings are discussed.

Infant apnea: findings on the barium esophagram.

Barium esophagrams of 160 infants who were being examined for apneic episodes were obtained at a referral center for the investigation of sudden infant death syndrome (SIDS). The studies were standardized as closely as possible to evaluate swallowing, esophageal function and anatomy, and the gastroduodenal regions. The level and frequency of gastroesophageal reflux were carefully assessed. The most common abnormality identified was gastroesophageal reflux (54%). Other abnormalities included nasopharyngeal reflux (27%), aberrant right subclavian artery (3%), and aspiration into the airway (3%). Swallowing dysfunction, esophageal dysmotility, antral dysmotility, chalasia, and tracheoesophageal fistula were each found in less than 1% of the infants.

Left ventricular outflow obstruction and necrotizing enterocolitis.

Two neonates had unusually rapid development of necrotizing enterocolitis within 24 hours of birth. Both patients had decreased systemic perfusion secondary to aortic atresia. Onset of either clinical or radiographic manifestations of necrotizing enterocolitis in the first day of life should alert one to the possible presence of severe left ventricular outflow obstruction.

CT of benign cystic abdominal masses in children.

Computed tomography (CT) correctly portrayed the gross anatomic features of six mesenteric, omental, and ovarian cysts and diagnosed two pancreatic pseudocysts in children. Large, well defined, low-density masses were found, often containing septa and filling most of the abdomen and pelvis. CT displayed the size and extent of the mass and showed extrinsic compression or displacement of surrounding structures. Different pathologic entities may have similar CT appearances, particularly with very large cystic masses.

Metastases to the breast.

Metastases to the breast are uncommon, with about 250 cases reported from clinical and autopsy series. The mammographic findings in 16 new cases revealed a spectrum of changes that included solitary or multiple lesions, well demarcated or poorly marginated masses, and diffuse involvement of skin or parenchyma or both. Diffuse disease was seen more frequently in this series (4/16), at times simulating inflammatory breast cancer. Although diagnosis of a primary malignancy usually preceded detection of the breast lesion, 40% (6/16) had no history of malignancy. Prognosis remains poor; however, it has improved in the lymphoma-leukemia group due to improved immunotherapeutic and chemotherapeutic regimens. The clinical, radiologic, and pathologic features are discussed. Some of the lesions encountered can be confused with a primary breast malignancy or a benign lesion, necessitating prompt and accurate biopsy to preclude unnecessary major surgery and to improve survival in cancers amenable to current therapy.

Radiographic findings in neonatal pneumonia.

The chest films of 30 infants with autopsy-proved pulmonary infections were reviewed to assess the radiographic changes in neonatal pneumonia. The most common abnormality identified was bilateral alveolar densities, noted in 77% of cases. One-third of patients had characteristically extensive, dense alveolar changes with numerous air bronchograms. A pattern of radiographic abnormalities consistent with transient tachypnea of the newborn was found in 17% of cases, and a second pattern resembling hyaline membrane disease was found in 13%. Recognition of the spectrum of expected radiographic changes can aid in the diagnosis of neonatal pneumonia, particularly if this information is correlated with the clinical features.

Basal ganglia calcification in the neonate.

Calcification of the basal ganglia developed following intracranial hemorrhage in a neonate recovering from severe perinatal asphyxia. Cranial computed tomography is useful in demonstrating the anatomic distribution of dystrophic calcification in regions previously involved by hemorrhage. The demonstration of hemorrhage or hemorrhagic infarction with CT may help to verify the association of basal ganglia calcification with birth anoxia.

Zonal colonic aganglionosis.

The customary approach to the diagnosis of Hirschsprung's disease is based on the existence of a single distal aganglionic region extending to the anal margin. Segmental aganglionosis, however, may involve only a limited segment of colon which is interposed between lengths of normal bowel. Awareness of this variant aids in the interpretation of the barium enema in children with signs and symptoms of aganglionosis, especially when the rectal biopsy is normal.

Fistulous communication of pseudocyst to the common bile duct: a complication of pancreatitis.

A pseudocyst developed in a child following acute pancreatitis and spontaneously drained into the common bile duct, a rare occurrence previously described only in adults. The imaging findings are similar to those of a choledochal cyst; serial sonograms enabled diagnosis by documenting evolution of the lesion and should be of value in demonstrating resolution.

Analysis of thermal stabilizing interactions in mesophilic and thermophilic adenylate kinases from the genus Methanococcus.

Adenylate kinases (ADKs) from four closely related methanogenic members of the Archaea (the mesophile Methanococcus voltae (MVO), the thermopile Methanococcus thermolithotrophicus (MTH), and the extreme thermopiles Methanococcus igneus (MIG) and Methanococcus jannaschii (MJA)) were characterized for their resistance to thermal denaturation. Despite possessing between 68 and 81% sequence identity, the methanococcal ADKs significantly differed in their stability against thermal denaturation, with melting points ranging from 69 to 103 degrees C. The high sequence identity between these organisms allowed regions of the MVO and MJA ADKs to be exchanged, producing chimeric ADKs with significantly altered thermal stability. Up to a 20 degrees C increase or decrease in stability was achieved for chimeric ADKs, whereas 88% of the original protein sequence was maintained. Based on our previous structural modeling studies, we conclude that cooperative interactions within the hydrophobic protein core play an integral role in determining the differences in structural stability observed between the methanococcal ADKs. From comparisons of the effects of temperature on protein unfolding and optimal enzymatic activity, we also conclude that thermostability and enzymatic temperature optima are influenced differently by molecular modifications and thus that the protein flexibility required for activity and stability, respectively, is not unconditionally linked within the methanococcal ADKs.

Spontaneous penetration of an antireflux prosthesis into the stomach.

The Angelchik antireflux prosthesis is a ringlike device used in the surgical treatment of sliding hiatal hernia and gastroesophageal reflux. This article describes an unusual postoperative complication whereby the prosthesis had migrated into the lumen of the stomach.

CT of malignant pleural mesothelioma.

The CT scans, plain films, and clinical courses of nine patients with malignant pleural mesothelioma were reviewed to assess the value of computed tomography (CT) in the initial evaluation and follow-up of this malignancy. The initial pretreatment scans showed a typical lobulated rind of pleural tumor encasing the lung associated with variable amounts of pleural fluid. Local invasion of the mediastinum, pericardium, diaphragm, and contralateral thorax were well depicted on CT; unsuspected abdominal extension of tumor was demonstrated on CT scans of five patients. Serial scans during treatment provided objective evidence of either regression or growth of tumor mass, even when the patients' clinical status and plain films appeared stable.

Anomalies of pulmonary veins: usefulness of spin-echo and gradient-echo MR images.

OBJECTIVE: We compared the value of spin-echo and gradient-echo MR images in the evaluation of anomalies of pulmonary veins. MATERIALS AND METHODS: Fourteen patients with a variety of developmental anomalies of pulmonary veins underwent MR imaging examination. Axial T1-weighted spin-echo and gradient-echo MR images were evaluated retrospectively on separate occasions during which visualization of normal and anomalous pulmonary veins was determined. RESULTS: Of 52 pulmonary veins, 46 (88%) were identified on T1-weighted spin-echo images and 50 (96%) on gradient-echo images. Two patients had atresia of both left pulmonary veins. Of 14 anomalous veins, 11 (79%) were revealed on spin-echo images and 13 (93%) on gradient-echo images. CONCLUSION: Both spin-echo and gradient-echo MR images were accurate in revealing anomalies of pulmonary veins. In our study, gradient-echo images were equal or superior to spin-echo images.