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Biomedical subjects

R G Lee

Publications and source records attributed to R G Lee.

At least 145 records · Page 8Linked to original sources
PubMed1985

Marked eosinophilia in esophageal mucosal biopsies.

The significance of marked eosinophilic infiltration in esophageal mucosal biopsy specimens was evaluated in 11 patients. The patients were generally young, with an average age of 14.6 years; all had diffuse intraepithelial eosinophilia in several biopsies. Ten patients (91%) had evidence for reflux esophagitis, which was associated with esophageal stricture in three of the six patients older than 1 year. Marked esophageal eosinophilia might therefore indicate prolonged or severe gastroesophageal reflux. One patient with peripheral eosinophilia, a history of asthma, and concurrent idiopathic eosinophilic gastroenteritis lacked evidence of reflux and represents a case of idiopathic esophagitis. Critical review of the literature establishes three additional cases. Idiopathic eosinophilic esophagitis is an unusual variant of idiopathic, but presumably allergic, eosinophilic infiltration of the gastrointestinal tract.

Adolescent↗
PubMed1985

Dysplasia in Barrett's esophagus. A clinicopathologic study of six patients.

To evaluate the consequences of dysplasia in Barrett's esophagus, six patients with esophageal mucosal biopsies showing dysplastic Barrett's mucosa in the absence of clinically evident esophageal carcinoma were identified and their clinicopathologic features reviewed. The patients, four men and two women, averaged 60 years and had long histories of gastroesophageal reflux. Four patients had high-grade dysplasia; two had low-grade. Dysplastic Barrett's mucosa appeared to arise most commonly from specialized-type Barrett's mucosa. After a mean follow-up of 29 months, four patients, all with high-grade dysplasia, had esophageal resections. Three of the four were found to have invasive adenocarcinoma, which extended through the esophageal wall in two patients. The fourth patient had a noninvasive adenomatous polyp ("Barrett's adenoma"), an infrequently described form of dysplasia in Barrett's esophagus. The two patients with low-grade dysplasia had developed no clinical indications of carcinoma. The results confirm that dysplastic Barrett's mucosa, particularly the high grade, is a morphologic marker for adenocarcinoma. Biopsy surveillance of patients with Barrett's esophagus is histologically feasible, but prospective studies are required to prove its effectiveness.

Adenocarcinoma↗
PubMed1985

Delayed images of glucoheptonate distribution after renal transplant.

Thirteen consecutive patients who had undergone renal transplantation were scanned 24 hours after glucoheptonate injection to document the incidence of gastrointestinal activity mimicking urinary extravasation. In six of the 13 patients, the activity was clearly within the small bowel or the colon but, in seven patients, the activity was noted surrounding the renal allograft. Using scintigraphy alone, it could not be determined whether this appearance represented cecal activity or urinary extravasation.

Adult↗
PubMed1985

Simple liver perfusion model for NMR spectroscopic analysis.

We developed a model to study the perfused mouse liver by nuclear magnetic resonance spectroscopy and to sample perfusate as it exited the liver within a vertical-bore spectrometer. The technique consists of rapidly cannulating the portal vein for perfusate inflow, and then suspending the organ in a bath of perfusate. An outlet at the bottom of the NMR tube provides easy access to concentrated samples of the perfusate exiting the liver. A suction outlet located just above the liver removes excess perfusate from the NMR tube. The perfusing medium is oxygenated Krebs-Henseleit buffer perfused at 8 ml/min. We demonstrated excellent P-31 spectra on the mouse liver. The liver energy charge is maintained as reflected in a constant ATP/Pi. We also showed the effects of ischemia and anoxia upon the liver, and correlated these P-31 spectra with biochemical measurements of liver enzyme release. This model was adapted for use in an Oxford wide-bore (89-mm) 8.4 T magnet with a 2-cm NMR tube to study P-31 spectra, liver enzyme and electrolyte release in ischemic and anoxic livers, but it can be used for spectroscopy of any nuclei in any vertical-bore spectrometer.

Animals↗
PubMed1985

Sphincter of Oddi stenosis: diagnosis using hepatobiliary scintigraphy and endoscopic manometry.

To determine the role of radionuclide imaging in diagnosing sphincter of Oddi stenosis, 21 patients with symptoms suggesting this disorder underwent endoscopic retrograde cholangiopancreatography, cholescintigraphy, and, when possible, endoscopic manometry. Those patients with abnormal hepatobiliary scintigraphy results--based on our criteria of delayed biliary intestinal transit, abnormal duct size, and abnormal time-activity dynamics and obstruction--had a mean basal sphincter pressure of 38.5 mm Hg. Sphincter pressures could not be measured in six patients with sphincters too tight to cannulate. Ten patients who underwent hepatobiliary scanning both before and after sphincter surgery had normal scan results on the repeat study. Hepatobiliary imaging appears useful for diagnosis of sphincter of Oddi stenosis in selected patients in whom manometry cannot be performed and for objective assessment of response to therapy.

Adult↗
PubMed1985

Methotrexate and the liver.

The findings of liver studies in 29 patients who were treated with low dose pulse methotrexate for rheumatoid arthritis (RA) are described. The biopsy specimens of 22 patients (76%) showed liver abnormalities, but cirrhosis did not develop in any patient. There were no statistically significant differences in age, duration of treatment, or cumulative dose between patients in whom abnormal liver histology developed and those in whom it did not. Our findings showed that isolated elevations of the aminotransferase enzymes or alkaline phosphatase levels did not predict liver disease, nor did the absence of elevation of these enzymes assure the absence of liver disease. Serial elevations of the aminotransferase and/or alkaline phosphatase enzyme levels and the development of hypoalbuminemia during treatment were specific indicators of the development of liver disease. In the patients studied, significant liver disease did not develop before 2 years of therapy or with a cumulative dose of methotrexate of less than 1500 mg.

Adult↗
PubMed1984

Cerebral perfusion imaging with iodine 123-labeled amines.

Two amines, N-isopropyl p-iodoamphetamine and N,N,N'-trimethyl-N'-[2-hydroxyl-3-methyl-5-iodobenzyl]-1,3-prop anediamine, have been labeled with iodine 123. The brain uptake of these radioactive tracers is proportional to cerebral blood flow. These tracers are retained in the brain for a sufficiently long time so that imaging can be performed with standard, readily available instrumentation. Transaxial tomography with amines is useful in acute cerebral infarction, in which the x-ray computed tomographic scan may be normal for several days after onset of symptoms while the uptake of radioisotope-labeled amines will be altered immediately after the onset of the stroke. It is also useful in examining patients with cerebral vascular disease and in the preoperative examination of patients with partial epilepsy.

Amines↗
PubMed1984

Tissue effects of neodymium:YAG laser photoradiation of canine ureters.

Although the entire ureter and renal collecting system are accessible for endoscopic treatment with a neodymium:YAG, (Nd:YAG) laser, specifications for safe laser application within the ureter are not established. After various doses of Nd:YAG laser energy were delivered, the midureters of six mongrel dogs were studied to determine tissue effects. Doses which are appropriate within the bladder (35 watts X 2 seconds) resulted in perforation and urine leak from the ureters. Higher doses (60-65 watts) of short duration were tolerated without problems and nonstrictured healing ensued. Further studies are necessary before Nd:YAG laser treatment of mid-ureteral tumors is recommended.

Animals↗
PubMed1984

Peripancreatic lymph node enlargement in Hodgkin's disease, non-Hodgkin's lymphoma, and pancreatic carcinoma.

The distribution of enlarged lymph nodes in the upper abdomen and retroperitoneum were classified according to their relationship to the pancreas in 47 patients with non-Hodgkin's lymphoma; in nine patients with Hodgkin's disease; and in 40 patients with pancreatic carcinoma. Four patterns of lymph node enlargement were evident: (1) preaortic retropancreatic lymphadenopathy; (2) pancreaticosplenic lymphadenopathy; (3) isolated celiac and/or portal lymphadenopathy; and (4) diffuse extensive lymphadenopathy. Features differentiating lymphoma from primary pancreatic neoplasm are discussed.

Adult↗
PubMed1984

Congenital self-healing reticulohistiocytosis. Report of the seventh case with histochemical and ultrastructural studies.

A new case of congenital self-healing reticulohistiocytosis was studied with S-100 antibody and electron microscopy. Many tumor cells were S-100-positive and contained Langerhans cell (LC) granules and concentrically laminated dense bodies. Octopus-like bodies and wormlike bodies were also found. The formation of LC granules at the cytomembrane was frequently found, not only between the cytomembrane and its own villi, but also between the cytomembranes of adjoining cells. These findings strongly support the cytomembrane origin of LC granules in general.

Female↗
PubMed1984

Lack of elevation of platelet factor IV in plasma from patients with myocardial infarction.

Platelet factor IV and beta-thromboglobulin are protein constituents of platelet granules. Elevated levels of these proteins in plasma have been used as sensitive indicators of platelet degranulation. Clearance of platelet factor IV is much faster than that of beta-thromboglobulin after release of the proteins in vivo. Although increases of platelet factor IV have been observed in patients with infarction, the implication that they reflect pathogenetic phenomena such as coronary thrombosis has not been assessed explicitly. Accordingly, plasma samples obtained serially from 52 patients with acute myocardial infarction under rigorous conditions verified to minimize platelet degranulation in vitro were evaluated prospectively. Correlative studies were performed to detect left ventricular mural thrombus, and coronary thrombosis was assessed independently in selected patients with indium-111 platelet scintigraphy. Platelet factor IV was normal at the time of admission in patients with infarction, averaging 6.3 +/- 3.3 ng/ml, similar to values in 44 other patients with chest pain without subsequent infarction (5.7 +/- 2.7 ng/ml) and in 25 normal subjects (4.3 +/- 1.6 ng/ml). Platelet factor IV generally did not increase during hospitalization in patients with infarction despite recurrent chest pain, development of left ventricular thrombus or documented recurrent infarction. However, platelet factor IV increased consistently after invasive procedures, accounting for 104 of the total of 110 increases due to platelet activation in vivo as reflected by persistence of elevated levels of beta-thromboglobulin. Thus, platelet factor IV values generally remain normal despite acute myocardial infarction. Rare increases that occur reflect platelet degranulation in vitro due to sampling artifact or perturbations of platelets in vivo due to invasive procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Physiology of the basal ganglia: an overview.

The major anatomical connections of the basal ganglia are reviewed, emphasizing the inputs to the striatum and efferent projections from the major output nuclei, the internal segment of globus pallidus and the pars reticulata of substantia nigra. The results from lesioning experiments, electrical stimulation, and chronic recording of single neuron activity have provided a wealth of data concerning the physiology of the basal ganglia. Although the deficits resulting from disease of the basal ganglia are well recognized, the specific role which these structures play in the control of normal movements remains speculative.

Basal Ganglia↗
PubMed1984

Mucins in Barrett's esophagus: a histochemical study.

To define the mucin secretion of Barrett's esophagus, 132 biopsy specimens from 37 patients were studied with histochemical stains for mucins. Columnar mucous cells contained largely neutral mucins, but scattered cells in over 70% of the biopsies also produced sialomucins and sulfomucins. Goblet cells contained sialomucins, sulfomucins, or both. The distribution and relative proportions of mucins varied considerably among biopsies and among patients. Barrett's esophagus histochemically represents a heterogeneous, partially differentiated epithelium analogous to incomplete intestinal metaplasia of gastric mucosa.

Barrett Esophagus↗
PubMed1984

Predictive value of perfusion defect size using N-isopropyl-(I-123)-p-iodoamphetamine emission tomography in acute stroke.

Sixteen patients with acute cerebral infarction who were studied with N-isopropyl-I-123-p-iodoamphetamine (IMP) brain scans were followed to determine if the extent of perfusion abnormality was predictive of the clinical course. Lesion size and diminished density on the scans appeared to correlate well with presenting symptoms, but were not predictive of outcome. When evaluated by IMP scanning in conjunction with computerized tomography, however, a group of patients could be identified in whom therapy may improve prognosis.

Acute Disease↗
PubMed1984

Structure-function relationships of protoporphyrin-induced liver injury.

To further define the pathogenesis of protoporphyric liver disease, perfused rat livers received varying doses of protoporphyrin, and aberrations of hepatic ultrastructure and function were correlated. Results indicated that the relative canalicular volume was equally increased in all protoporphyrin-perfused livers; however, bile flow was only minimally diminished at the smallest protoporphyrin dose employed. Protoporphyrin injured microvilli at the sinusoidal pole and reduced the surface density of the endoplasmic reticulum in a dose-related fashion. No crystalline or amorphous material was detectable, and only slight mitochondrial distortions occurred. Thus, cholestasis did not correlate with canalicular dilatation, the presence of crystalline material, or mitochondrial changes. Liver plasma membrane abnormalities appeared to correlate with functional defects and support a direct hepatotoxicity. Long-term protoporphyrin overload studies are needed to assess differences between hepatic and erythroid (parenteral) sources of protoporphyrin overproduction.

Animals↗