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Biomedical subjects

S Wallace

Publications and source records attributed to S Wallace.

At least 19 recordsLinked to original sources
PubMed1992

Parenchymal changes of the liver in cholangiocarcinoma: CT evaluation.

We evaluated parenchymal changes of the liver in 92 patients (41 peripheral types and 51 hilar types) with cholangiocarcinomas studied by bolus-enhanced computed tomography (CT). In 39% of patients with the peripheral type, a wedge-shaped increased enhancement of the liver was observed peripheral to the tumor on bolus-enhanced CT. Tumor was observed in all cases. In 58.8% of patients with the hilar type, a segmental or lobar increased degree of enhancement of the liver was observed, but the tumor was demonstrated in only 58.8%. Atrophy was accompanied by areas of increased enhancement in 80% of hilar type and 25% of peripheral type. Areas of increased degree of enhancement corresponded to a wedged-shaped perfusion defect on CT during arterial portography. On magnetic resonance imaging (MRI), those lesions showed hyperintensity on T2-weighted images. Most of these changes were considered to be due to reversible hepatic parenchymal ischemia secondary to portal vein invasion by the tumor.

Adenoma, Bile Duct↗
PubMed1992

Automated DNA sequencing and analysis of 106 kilobases from human chromosome 19q13.3.

A total of 116,118 basepairs (bp) derived from three cosmids spanning the ERCC1 locus of human chromosome 19q13.3 have been sequenced with automated fluorescence-based sequencers and analysed by polymerase chain reaction amplification and computer methods. The assembled sequence forms two contigs totalling 105,831 bp, which contain a human fosB proto-oncogene, a gene encoding a protein phosphatase, two genes of unknown function and the previously-characterized ERCC1 DNA repair gene. This light band region has a high average density of 1.4 Alu repeats per kilobase. Human chromosome light bands could therefore contain up to 75,000 genes and 1.5 million Alu repeats.

Amino Acid Sequence↗
PubMed1992

Pulmonary artery pressure measurement in patients with elevated pressures: effect of backrest elevation and method of measurement.

OBJECTIVE: To determine whether pulmonary artery pressure measurement is accurate if the head of the bed is elevated; to compare the end-expiratory graphic recording and digital monitor methods for pulmonary artery pressure measurement; to determine whether either mean arterial pressure or mixed venous oxygen saturation changes during backrest elevation. DESIGN: Nonrandomized clinical trial. SETTING: A six-bed cardiac surgical intensive care unit of a 540-bed federal facility. POPULATION: Twenty-five postoperative cardiac surgical patients with elevated pulmonary artery pressures (systolic higher than 35 mm Hg). INTERVENTIONS: In supine patients pulmonary artery pressures were measured at each of the following backrest elevations: 0, 20, 30, 45 and again at 0 degrees. Measurements were obtained once during mechanical ventilation and once during normal breathing after extubation. MAIN OUTCOME MEASURES: End-expiratory graphic recording of pulmonary artery pressures; digital monitor values of pulmonary artery pressures; mean arterial pressure; and mixed venous oxygen saturation. RESULTS: No statistical difference was found in pulmonary artery pressures measured at each of the backrest elevations during mechanical ventilation or normal breathing after extubation. Pulmonary artery diastolic and pulmonary capillary wedge pressures obtained with the digital monitor method were significantly lower than the end expiratory graphic recording method during normal breathing after extubation but not during mechanical ventilation. No changes in mean arterial pressure or mixed venous oxygen saturation occurred during backrest elevation. CONCLUSIONS: These results show that pulmonary artery pressures can be measured accurately with the head of the bed in an elevated position. The data indicate that obtaining pulmonary artery pressure measurements from the digital display of the bedside monitor is accurate when respiratory wave form fluctuations are minimal but may lead to inaccurate values with prominent respiratory fluctuations. Further research is needed to validate this finding in different patient populations and with other models of monitoring equipment.

Adult↗
PubMed1979

Arterial occlusion of pelvic bone tumors.

Arterial occlusion of the internal iliac artery was successful in the relief of pain due to primary and secondary neoplasms of the bony pelvis in 8 of 9 patients. These included 3 giant cell tumors, 1 aneurysmal bone cyst, 1 recurrent chondrosarcoma, 3 metastatic renal cell carcinoma and 1 metastatic clear cell sarcoma. Calcification of the margin of the lesion occurred in 3 of 4 primary neoplasms after infarction. The transcatheter arterial occlusion was accomplished utilizing Gelfoam and stainless steel coils. Although most patients experienced pain and fever for several days following the procedure, no permanent sequelae or complications were encountered.

Adenocarcinoma↗
PubMed1979

Metastatic osteogenic sarcoma to the brain.

The radiographic appearances of intracranial metastases from primary osteogenic sarcomas in three patients are presented. In two patients, the diagnosis of metastatic disease could be made on conventional roentgenograms of the skull since mineralization of tumor osteoid could be seen within the brain parenchyma. This had a similar appearance to the primary bone tumor. Angiography in two of the three patients revealed the cerebral metastases to be hypervascular with tumor vessels, tumor stain and early draining veins.

Adolescent↗
PubMed1979

Computerized tomography in rhabdomyosarcoma of the head and neck.

Rhabdomyosarcoma of the head and neck may be treated with surgery, radiotherapy and chemotherapy or a combination thereof. Precise delineation of the full extent of the tumor in the head and neck is essential. Routine radiographs with hypocycloidal tomography and CT are complementary in defining the full extent of the lesion. Tomography is superior to CT scanning in demonstrating fine bone detail. Demonstration of the soft tissue tumor and its extensions is better seen on CT. The ability to discriminate differences more accurately in densities allows computerized tomography to appreciate better the integrity of the bone margins such as the thin walls of the sinuses.

Adolescent↗
PubMed1979

Angiography in giant-cell bone tumors.

Angiography was performed on 48 patients with giant-cell bone tumors. Sixty-four per cent were hypervascular; 25% were hypo- or moderately vascular; and 10% were avascular. Findings were similar in the 45 benign and 3 malignant tumors. There was no correlation between the findings and degree of histological aggressiveness. There was a high (60%) incidence of aneurysmal bone cyst component in the hypovascular group. Hyperemic synovium, occasionally simulating tumor, was seen in 80% of surgically proved lesions. Angiography was useful in assessing tumor extent, particularly when an extraosseous component was present.

Adolescent↗
PubMed1979

Computed tomographic arteriography of the liver.

Computed tomographic arteriography (CTA) of the liver performed during intra-arterial infusion of contrast material improved the detection of hepatic lesions in 10 of 12 patients and was the only method that accurately determined the extent of disease in 6. This technique has significant advantages over conventional hepatic computed tomography with or without intravenous contrast enhancement, or selective hepatic angiography. It is recommended in the evaluation of selected patients, especially when there is a discrepancy between the findings obtained by other methods.

Angiography↗
PubMed1979

The sella turcica in primary end organ failure.

Pituitary hyperplasia, or adenoma, may result from end or target organ failure as seen in primary hypothyroidism and hypogonadism. Associated enlargement of the sella turcica and contour alterations without significant increase in volume may be seen. A review was made of 12 patients with end organ failure demonstrating the spectrum of radiologic changes within the sella turcica. Recognition of pituitary enlargement resulting from end organ failure may eliminate unnecessary surgery.

Adenoma↗
PubMed1979

Transcatheter occlusion of the gastroduodenal artery.

The gastroduodenal arteries of 7 patients were occluded for treatment of duodenal bleeding in 4, hepatic devascularization in 2, and redistribution of blood flow for intra-arterial chemotherapy in one patient. In 6 patients, occlusion was performed with Gianturco coils, and with Gelfoam in one. No major complication was encountered. This approach was successful in the control of bleeding from peptic ulcers, arteriovenous malformation and invasion of duodenum by retroperitoneal metastatic lymph nodes from carcinoma of the testicle. Occlusion of the gastroduodenal artery was utilized for further dearterialization of hepatic neoplasms. Redistribution of hepatic blood flow was accomplished by the occlusion of the gastroduodenal and replaced right hepatic arteries allowing infusion of chemotherapeutic agents into the entire liver through the left hepatic artery.

Adenoma, Bile Duct↗
PubMed1979

Lymphangiography in staging of carcinoma of the prostate: the potential value of percutaneous lymph node biopsy.

Bilateral pedal lymphangiography was performed in the staging of 208 patients with prostatic carcinoma. Forty-seven (23%) were found to have lymph node involvement, and 40 of these 47 had Stage C disease. Nine per cent of the Stage C1 patients (moderately advanced disease) and 37% of Stage C2 (massive carcinoma) had lymph node metastases. The distribution of the abnormal nodes was in continuity with the lymph node drainage from the prostate. The external iliac nodes were the most frequent site of metastases. Histological confirmation was obtained in 20 of the 40 positive Stage C2 cases. More recently, percutaneous aspiration biopsy of the opacified nodes was used to document the presence of metastic disease, thereby extending the value of lymphangiography.

Carcinoma↗
PubMed1979

"Mini" Gianturco stainless steel coils for transcatheter vascular occlusion.

Small stainless steel coils have been developed for transcatheter vascular occlusion procedures. The coils can be passed through a 5-French polyethylene catheter, extending the clinical applications of coil occlusion procedures for small and/or tortuous vessels. Two cases describing the use of these coils are reported.

Adult↗
PubMed1979

Transcatheter arterial occlusion in the management of rectosigmoidal bleeding.

Transcatheter arterial occlusion was performed in five patients with recurrent rectosigmoidal bleeding. Four had malignant neoplasms, and the fifth, an arteriovenous malformation. The superior hemorrhoidal artery was embolized in two patients, the inferior mesenteric artery in two, and the left internal iliac artery in one patient. In four patients, immediate and complete control of rectal bleeding was achieved, and gradual control was accomplished in the fifth patient. Left lower quadrant pain and fever developed in three patients. The possibility of rectosigmoidal bleeding from the internal iliac artery is stressed.

Adult↗
PubMed1979

Arterial occlusion in the management of pain from metastatic renal carcinoma.

Arterial embolization was performed in nine patients with metastases from renal carcinoma who had severe pain resistant to conventional therapy. Patients with metastases in the ilium (four), the lumbosacral spine (one), and the base of the skull (one) experienced pain relief lasting from one to six months. The other three patients, who had metastases in the proximal femur, underwent preoperative embolization to facilitate tumor curettage and internal hip fixation. No significant complications were seen with this therapeutic approach.

Aged↗
PubMed1979

Computed tomography diagnosis of mesenteric masses.

The computed tomographic findings of 30 mesenteric masses are presented. To delineate the mesentery accurately, oral contrast material must fill the entire small bowel. Of the masses, 23 were secondary to non-Hodgkin's lymphoma. These masses were irregular in shape and homogeneous in their tissue attentuation. Two of the 23 had a normal lymphangiogram in the upper paraaortic area. Both lymphangiography and CT were necessary to define the extent of disease in such patients. The six mesenteric metastases were irregular in shape. Four of these had areas of decreased attentuation eccentrically located within the mass which may be secondary to necrosis. One mesenteric cyst had a circular shape with smooth, sharp borders, and a centrally located area of decreased attenuation.

Adult↗
PubMed1979

Comparison of scintigraphy, sonography, and computed tomography in the evaluation of hepatic neoplasms.

A comparison of scintigraphy, ultrasonography, and computed tomography (CT) in 94 proven patients with clinically suspected liver disease is reported. CT proved to be the most accurate in detecting masses and assessing the complete extent of intrahepatic disease. The most reliable combination was CT and scintigraphy. The specific advantages and disadvantages of each method are discussed. The diagnostic scheme followed in the imaging evaluation of an hepatic mass in our clinical practice is discussed.

False Negative Reactions↗
PubMed1979

Radiographic features of olfactory neuroblastoma.

Olfactory neuroblastomas are malignant, slowly growing neurogenic tumors originating from the olfactory mucosa of the nasal cavity. Fourteen patients with this tumor were evaluated and showed variable extension into adjacent structures such as the ethmoid and sphenoid sinuses, orbit, and anterior cranial cavity.

Adolescent↗