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Biomedical subjects

L Lee

Publications and source records attributed to L Lee.

At least 325 records · Page 18Linked to original sources
PubMed1984

Prognostic significance of morphology of tumor and retroperitoneal lymph nodes in epithelial carcinoma of the ovary. II. Correlation with survival.

Correlation between prognostic indices derived from morphologic studies of retroperitoneal lymph nodes as well as primary tumor and survival in 39 patients with epithelial carcinoma of the ovary is reported. All had maximal surgery, adjuvant chemotherapy, and were followed for more than 2 years. A selective biopsy of pelvic and para-aortic lymph nodes was performed during the staging laparotomy in all instances. The chemotherapeutic regimen was a combination of Adriamycin, cis-platinum, and Cytoxan in a majority of cases. Prognostic indices, which showed positive correlation with survival, were cancer involvement, type of lymph node reaction, sinus histiocytosis, and fibroblastic proliferation in the regional lymph nodes; tumor grade, lymphocytic infiltration, stromal fibrosis, and histologic type in primary tumor; and stage of disease. Unfavorable factors for survival were nodal metastasis, lymphocytic depletion in abdominal nodes, and Grade 3 tumor. Clinical implications of our findings are discussed.

Adenocarcinoma↗
PubMed1984

Effect of RNase on Zein Synthesis in Endosperms of brittle-2opaque-2 Maize Double Mutant.

Posttranscriptional degradation of zein mRNAs in Zea mays, presumably caused by high RNase activity, may be involved in reducing zein synthesis in the endosperms of zein-deficient mutants. Zein proteins prepared from mature endosperms of zein-deficient double mutants such as brittle-2;opaque-2 showed an almost complete blockage of the synthesis of two major zein components, Z1 and Z2. However, these two components were present prior to 12 days postpollination. The changes in quantity and quality of zein synthesis in these double mutants correlated well with the rising RNase levels in the developing endosperm. In addition to its effect on zein synthesis, high RNase activity also influenced the stability of rRNAs in the brittle-2;opaque-2 double mutant at the later stages of endosperm development. These results suggest that RNase played a role in regulating zein synthesis in developing zein-deficient mutant endosperms.

Journal Article↗
PubMed1984

Isolation and characterization of an unsaturated fatty acid-binding protein from developing chick neural retina.

An unsaturated fatty acid-binding protein has been isolated from the cytosol fraction of developing chick neural retina. It has a molecular weight of approximately 14,800 and specifically binds not only added radiolabeled arachidonic and oleic acids but has also been found to bind unsaturated fatty acids endogenously. This protein was detected in chick neural retina at all stages examined, from 8 to 16 days of development. It is also present in chick heart, brain, and retinal pigmented epithelium-choroid as well as in adult bovine neural retina. It is distinct from both cellular retinol-binding protein and cellular retinoic acid-binding protein on the bases of binding specificity and isoelectric point.

Amino Acids↗
PubMed1984

Rat intestinal maltase--glucoamylase. Purification of the detergent-solubilized enzyme in the presence of protease inhibitors: properties and identification of a protease-sensitive subunit.

Failure to develop clear-cut, distinguishing characteristics for hydrophobic and hydrophilic forms of maltase-glucoamylase led us to attempt the purification of the detergent-extracted enzyme in the continuous presence of protease inhibitors (phenylmethylsulfonyl fluoride and N-ethylmaleimide). The enzyme was purified by molecular exclusion, anion-exchange, and affinity column chromatography to a final specific maltase activity of 80 U/mg protein, comparable to previously solubilized enzymes. Both detergent (d-maltase) and proteolytically (p-maltase) solubilized enzymes had identical Km's for maltose and similar glycogenase activity. d-Maltase was clearly amphipathic. Whereas 95% of p-maltase was eluted with aqueous buffer from an octyl-Sepharose CL-4B column, the elution of d-maltase required solutions containing Triton X-100 and ethylene glycol. On density gradient centrifugation and sodium dodecyl sulfate (SDS)--polyacrylamide gels, p-maltase migrated as one high molecular weight species of 500,000. In contrast d-maltase migrated heterogeneously and the smallest maltase-active forms delineated by these two techniques, as well as by high pressure liquid chromatography, had molecular weights which ranged from 120,000 to 15,0000. Both p- and d-maltase were dissociated by heat in SDS, forming five prominent species as we have previously described. In contrast to p-maltase, in which the smallest species, band 1, equalled 36.7% of the total mass, band 1 of d-maltase accounted for 66.5%. Band 1 was separable when smaller amounts of enzyme were applied to slab gels and stained with silver, into two proteins of 130,000 and 145,000 daltons. The 145,000 dalton protein was absent in p-maltase and was replaced by a faint band of 140,000 daltons.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1984

Choroideremia: a clinical, electron microscopic, and biochemical report.

An asymptomatic 19-year-old male with choroideremia had diffuse loss of retinal pigment epithelium (RPE) and choroid except for the periphery and macula. Fluorescein angiography of the arteriovenous phase showed absence of retinal pigment epithelium and exaggerated visualization of choroidal vessels in involved areas. The mother was a typical carrier with pigment stippling of the midperipheral retina. Histopathologic examination of affected areas of one eye showed marked degeneration of the outer and midretina with loss of retinal pigment epithelium and Bruch's membrane, absence of choriocapillaris, chorioretinal adhesions and gliosis. Atrophy of inner and mid-choroid was also observed. Pigmented macrophage-like cells had migrated into the outer and midretinal layers. Electron microscopy disclosed macrophage-like cells with trilaminar structures and photoreceptor phagosomes in the RPE and outer retina. Remnants of photoreceptor outer segments were adherent to the plasma membranes of the macrophage-like cells. Biochemical analysis of retinal tissue samples for interphotoreceptor retinoid-binding protein (IRBP) showed marked reduction in the 146K bands in the equator and posterior pole in the patient compared to controls. Cyclic nucleotide content was altered in the retinal equator. Cyclic AMP was several-fold higher in the RPE-choroid complex of the affected eye than in the control.

Adult↗
PubMed1984

Colipase and lipase secretion in childhood-onset pancreatic insufficiency. Delineation of patients with steatorrhea secondary to relative colipase deficiency.

Pancreatic lipase and colipase secretion was assessed in 64 patients with pancreatic disease, 24 of whom had steatorrhea, and in 14 control subjects. A wide range of lipase and colipase secretion was seen in patients both with and without steatorrhea. Considerable loss of pancreatic lipase and colipase secretion had to occur before steatorrhea developed, as the highest hourly secretion of lipase and colipase in this group of patients was less than 4% and less than 2%, respectively, of the lowest values recorded in normal subjects. Colipase and lipase outputs were very strongly correlated (r = 0.96) throughout the range of pancreatic function. Lipase was always unsaturated with respect to colipase, but in only a limited number of patients with relatively low pancreatic secretion was the degree of unsaturation greater than 2 standard deviations below the mean. The importance of low saturation or low colipase secretion was evident in a group of 11 patients with a narrow range of lipase secretion in a transitional zone between secretion rates associated with steatorrhea and with normal fat excretion. In this group, 7 patients were identified in whom colipase deficiency appeared to be the sole cause of steatorrhea. The correlation of colipase secretion with the level of fecal fat excretion was highly significant (p less than 0.001) and indicated that fat digestion and subsequent fat absorption depended on colipase secretion up to at least a level of 25% fecal fat excretion. Nonpancreatic factors could well govern the extent of fat absorption above this level, as colipase secretory values in this range were uniformly low.

Adolescent↗
PubMed1983

Use of lanthanide-induced nuclear magnetic resonance shifts for determination of protein structure in solution: EF calcium binding site of carp parvalbumin.

The binding of the paramagnetic lanthanide ion ytterbium to the calcium binding protein carp parvalbumin results in a series of 1H NMR resonances which are shifted far outside the envelope of the 1H NMR spectrum of the diamagnetic form of the protein; bound Yb3+ also induces shifts in the 13C NMR spectrum of parvalbumin and in the 113Cd NMR spectrum of cadmium-substituted parvalbumin. The interpretation of these lanthanide-shifted resonances in terms of the structure of the protein surrounding the metal binding site requires the determination of the orientation and principal elements of the magnetic susceptibility tensor of the protein-bound Yb3+ ion. A previous comparison [Lee, L., & Sykes, B. D. (1982) Biomolecular Structure Determination by NMR (Bothner-By, A. A., Glickson, J. D., & Sykes, B. D., Eds.) pp 169-188, Marcel Dekker, New York] of the observed Yb3+-shifted 1H NMR spectrum of parvalbumin with a calculated spectrum, based upon the X-ray structure and an initial determination of the magnetic susceptibility tensor, led to the conclusion that there were significant differences between the solution and X-ray structures. In this paper, the magnetic susceptibility tensor has been reevaluated with the aid of newly assigned 13C and 113Cd NMR resonances. The agreement between the calculated and observed spectra is now close overall.

Animals↗
PubMed1983

Purification of an insulin-like growth factor II receptor from rat chondrosarcoma cells.

An insulin-like growth factor II (IGF-II) receptor was purified from rat chondrosarcoma cells by Triton X-100 solubilization of a 100,000 X g membrane preparation and affinity chromatography on a multiplication-stimulating activity (MSA)-Sepharose column. Analysis of the purified receptor by sodium dodecyl sulfate-gel electrophoresis and silver staining showed a major band of Mr = 210,000 (Mr = 250,000 after reduction with dithiothreitol). When 125I-MSA was chemically cross-linked to the purified receptor and analyzed by sodium dodecyl sulfate-gel electrophoresis (with and without dithiothreitol) and autoradiography, the radioactive bands coincided with the Mr = 210,000 and 250,000 bands identified by silver staining. The purified receptor also appeared to contain an Mr = less than 68,000 species identified by silver staining in addition to the Mr = 250,000 binding component. IGF-I, IGF-II, and MSA-II inhibited binding of 125I-MSA to the purified receptor with the same relative potency as for binding to the intact chondrosarcoma cell (IGF-II greater than MSA-II greater than IGF-I), and insulin did not inhibit binding. The association constant (K alpha) for MSA-II binding to the purified receptor was 2 X 10(9) M-1. The purified receptor bound to concanavalin A-Sepharose and wheat germ lectin-Sepharose columns and was eluted with alpha-methyl-D-mannoside and N-acetyl-D-glucosamine, respectively, showing that the receptor is a glycoprotein.

Animals↗
PubMed1983

The presence of a soluble interphotoreceptor retinol-binding protein (IRBP) in the retinal interphotoreceptor space.

A new, gentle technique has been developed for washing of the retinal interphotoreceptor space (IPS) to obtain soluble components of the extracellular matrix (ECM). Using this method, we have determined that the major soluble constituent of monkey IPS is a 146,000 Mr glycoprotein, which binds [3H]retinol, sediments on sucrose gradients at 7S and has an Rf of 0.42 on native gel electrophoresis. Using size-exclusion high performance liquid chromatography, the apparent molecular weight of the native protein was calculated to be 250,000 daltons. In contrast to previous studies, no 15,000-dalton cellular retinol-binding protein (CRBP) or 33,000-dalton cellular retinaldehyde-binding protein (CRALBP) was observed in the IPS wash, indicating that these proteins are probably not involved in retinol transport between retina and pigment epithelium (PE). In the supernatant fraction of retinal homogenates that contains soluble intracellular proteins as well as extracellular constituents, the 146,000 Mr protein was closely associated with a 93,000 Mr protein that could be separated on SDS-gel electrophoresis; the 93,000 Mr protein was not found in the IPS wash. The 146,000 Mr interphotoreceptor retinol-binding protein (IRBP) may function in extracellular retinol transport in the IPS.

Animals↗
PubMed1983

Incidence of para-aortic and pelvic lymph node metastases in epithelial carcinoma of the ovary.

In patients with ovarian carcinoma, the presence of metastatic disease in a retroperitoneal lymph node is indicative of a poor prognosis. Although a "staging laparotomy" is required for proper treatment, definitive information concerning para-aortic and pelvic lymph node metastasis often is not available. To determine the incidence of retroperitoneal lymph node metastases in untreated cases of ovarian carcinoma, a prospective study by selective nodal biopsy was undertaken in 61 unselected patients with the following distribution: Stage I, 11; Stage II, 10; Stage III, 31; and Stage IV, 9. The incidence of para-aortic node metastasis overall was 37.7% and of pelvic node metastasis, 14.8%. Of 23 patients with positive para-aortic nodes, 30.4% had no concomitant pelvic node involvement. Direct relationships between nodal metastasis and clinical stage, tumor grade, and histologic type of tumor were demonstrated. The incidence of positive para-aortic nodes in Stage I disease was 18.2%; in Stage II, 20.0%; in Stage III, 41.9%; and in Stage IV, 66.7%. The corresponding incidence of pelvic node metastasis was 9.1% in Stage I, 10.0% in Stage II, 12.9% in Stage III, and 33.3% in Stage IV. Grade 3 tumors were associated most frequently with nodal involvement, with an incidence of positive para-aortic nodes of 52.5% and of positive pelvic nodes of 15.5%. In patients with a serous type of malignancy, the frequencies of positive para-aortic/pelvic nodes were 44.4%/16.7%, respectively; in the undifferentiated type, 50.0%/10.0%; in the clear cell type, 25.0%/25.0%; and in the mucinous type, 14.3%/14.3%. In this small series, 32 patients (52.5%) had positive retroperitoneal nodal involvement. It is concluded that selective biopsies of the para-aortic and pelvic lymph nodes should be part of any "staging laparotomy" for ovarian carcinoma, and that the true incidence of nodal involvement in these patients awaits further investigation.

Adult↗
PubMed1983

Retroperitoneal lymph node metastases in Stage I carcinoma of the endometrium: correlation with risk factors.

The present study was undertaken in patients with Stage I carcinoma of the endometrium to correlate risk factors and the prevalence of retroperitoneal lymph node metastases. From January 1975 to April 1983, 202 patients with Stage I disease had initial therapy at the Long Island Jewish-Hillside Medical Center, New Hyde Park, New York. Among these patients, 74 who had total abdominal hysterectomy, bilateral salpingo-oophorectomy, and selective lymph node biopsy without preoperative radiation were included in the study. Results indicate that risk factors associated with nodal metastasis were Grade 3 tumor (42.1%), papillary adenocarcinoma (28.6%), deep myometrial invasion (42.9%), surface extent of tumor growth greater than 1/3 of the endometrial cavity (31.8%), and a diffuse pattern of tumor growth (17.2%). In Stage 1 endometrial cancer with any of the above 5 risk factors, it is urged that a selective biopsy of para-aortic and pelvic nodes during hysterectomy should be performed.

Adenocarcinoma↗
PubMed1983

An optical stopped-flow and 1H and 113Cd nuclear magnetic resonance study of the kinetics and stoichiometry of the interaction of the lanthanide Yb3+ with carp parvalbumin.

The rate constants for the dissociation of the lanthanide Yb3+ from the CD and EF calcium-binding sites of carp parvalbumin (isoelectric point, 4.25) have been measured using optical stopped-flow and 1H nuclear magnetic resonance (NMR) methods. The off-rate constants for Yb3+ are 1.5 X 10(-1) and 1.3 X 10(-3) s-1, respectively, at pH 6.6 and 23 degrees C. The relative displacement of Ca2+ from the two sites by Yb3+ was determined from the observed amplitude of the fast and slow kinetic phases. Yb3+-shifted 1H-NMR spectra of parvalbumin are presented as a function of pH, concentration, and H2O:D2O ratio to relate the NMR results to the kinetic and optical results. The displacement of Cd2+ from parvalbumin by Yb3+ was studied using 113Cd NMR. All of the results show the sequential displacement of Ca2+ from the CD and EF sites of parvalbumin by Yb3+. Some results are also presented for Tb3+ and Gd3+.

Animals↗
PubMed1983

Evaluation of the dopamine response to stress in man.

Because the role of circulating dopamine (DA) in the sympathetic nervous system response to stress remains unclear, alterations in peripheral DA concentrations were determined in healthy volunteers after assuming upright posture (n = 6), hand immersion in ice water (cold pressor, n = 6), and insulin-induced hypoglycemia (n = 11) and in 17 comatose patients with severe brain injury (11 head trauma and 6 intracranial hemorrhage). Changes in DA levels were compared to increases in epinephrine (E) and norepinephrine (NE), all of which were measured by the radioenzymatic technique. The minimum sensitivities were 42, 22, and 38 pg/ml, respectively. In 19 normal men and 22 women, basal DA levels were below assay sensitivity in 31 and were 85 +/- 7 (+/- SE) pg/ml in the remainder. Plasma E was measurable in all but 7 subjects, with a mean concentration of 41 +/- 4 pg/ml. NE levels were 201 +/- 17 pg/ml in 30 of the 31 subjects in whom it was detectable. There was no sex difference for any of the catecholamines. Upon standing, neither DA nor E changed significantly, but NE, increased by 176 +/- 40 pg/ml (P less than 0.0025). There were no significant changes in DA or E concentrations during the cold pressor test, while NE increased by 212 +/- 66 pg/ml (P less than 0.025). Compared to the E (1044 +/- 356 pg/ml; P less than 0.02) and NE (233 +/- 62 pg/ml; P less than 0.005) increments after hypoglycemia, the maximal DA increment, although significant (62 +/- 22 pg/ml; P less than 0.025), was less than those of the other catecholamines. DA levels were measurable in only 7 of 40 samples from 17 brain-injured patients and was 72 +/- 13 pg/ml in the remainder. However, E and NE levels were detectable in 79% of the samples and were significantly greater than normal (125.6 +/- 14 and 594 +/- 59 pg/ml; P less than 0.001, respectively). It is concluded that basal DA levels are generally below the assay limits of detectability. Furthermore, measurement of circulating levels suggests that DA participates in the general sympathetic response only when the adrenal component is maximally activated.

Adolescent↗
PubMed1983

Loss of adrenocortical suppression after acute brain injury: role of increased intracranial pressure and brain stem function.

The function of the pituitary-adrenal axis was studied in 23 acutely brain-injured, comatose patients (14 head trauma and 9 intracranial hemorrhage), who were treated with dexamethasone (16-64 mg/daily). Patients with normal intracranial pressure (ICP) and normal brain stem function (group 1) had decreased plasma cortisol levels (less than or equal to 5 micrograms/dl) within 36 h (mean +/- SEM, 2.4 +/- 0.3 microgram/dl; t 1/2, 18 h). In contrast, patients with elevated ICP (i.e. greater than 20 mm Hg; midline shift, or compressed ventricles) and normal brain stem function (group 2) had persistently elevated cortisol concentrations (15.4 +/- 2.6 micrograms/dl; P less than 0.001). Superimposition of brain stem dysfunction resulted in generally low cortisol levels regardless of the presence (group 4; 3.9 +/- 1.0 microgram/dl; P less than 0.001 compared to group 2) or absence (group 3; 2.1 +/- 0.5 microgram/dl) of elevated ICP. Plasma ACTH levels in 31 samples obtained before or during dexamethasone therapy in 14 patients irrespective of group were not elevated (45.6 +/- 12.5 pg/ml); there was no correlation between plasma ACTH and cortisol levels. Despite elevated cortisol values in group 2, ACTH levels were low (22.4 +/- 10.1 pg/ml). It is concluded that elevated ICP in the presence of normal brain stem function is a potent stimulus for adrenocortical activation which is not associated with elevated ACTH levels, and that the brain stem is involved in this response.

Adrenal Cortex↗
PubMed1982

Models for slow anisotropic rotational diffusion in saturation transfer electron paramagnetic resonance at 9 and 35 GHz.

Model systems of cholestane and 5-doxylstearic acid analogue spin probes in lipid bilayer dispersions of dipalmitoylphosphatidylcholine and cholesterol (9:1 w/w) are used to analyze saturation transfer electron paramagnetic resonance spectral behavior for slow rotational diffusion in an anisotropic medium. Measurements are made at both 9 and 35 GHz to provide enhanced spectral resolution for different types of motion. Parameter correlation plots of spectral parameters from different regions of the saturation transfer spectra appear to be potentially useful in characterizing different types of motion. Anisotropic rotational diffusion about a symmetry axis coincident with the nitroxide y principal axis is clearly distinguishable from isotropic rotational diffusion and may be distinguishable from rotational diffusion about the nitroxide z principal axis. Approximate anisotropic rotational diffusion about a symmetry axis coincident with the nitroxide z principal axis is distinguishable from isotropic rotational diffusion under some, but not all, conditions.

Cholestanes↗
PubMed1982

Soluble neutral maltase--glucoamylase from the small intestine: separation and characterization of components with differing affinity for concanavalin A.

Intestinal maltase with a neutral pH optimum exists in both a brush border membrane-bound form and a soluble form in suckling rat intestine. Previous experiments in our laboratory have shown that the soluble enzyme contains a component which binds much more tightly to concanavalin A (ConA) than solubilized forms of the membrane enzyme. We studied the origin of this component by subjecting neutral, soluble maltase activity to chromatography on Sepharose 4B at age 13, 18 (preweaning), and 25 (postweaning) days. At 13 days, two maltase peaks were obtained with approximate molecular weights of 400 000 (peak I) and 150 000 (peak II). Peak II was less prominent at 18 days and was absent at 25 days. At 13 days, the majority of peak I consisted of material which was bound between 0.025 and 0.05 M alpha-methyl mannoside on gradient elution chromatography of ConA-Sepharose. Peak II contained material which eluted between 0.075 and 0.3 M alpha-methyl mannoside. At 25 days, all of the soluble maltase eluted between 0.025 and 0.04 M alpha-methyl mannoside. Peak I and peak II maltases had similar pH optima and Km's for maltase. Peak II maltase had a fourfold greater activity toward glycogen than peak I maltase with approximately the same activity for palatinose, turanose, and trehalose. Both maltases were precipitated by an antibody raised against adult membrane-bound maltase. Soluble maltase with neutral pH activity in the suckling rat intestine, therefore, consists of two immunologically related isozymes which differ in their molecular weight, their binding by ConA, and their specificity for glycogen. The small isozyme disappears at or about the time of weaning.

Animals↗