PubMed Health⌕ Search

Biomedical subjects

A Glass

Publications and source records attributed to A Glass.

At least 37 records · Page 2Linked to original sources
PubMed1992

[Time-resolved fluorescence of europium ions and its application for determination of biologically active substances].

At present radioimmunoassay is still one of the most widely used analytical procedure. It is, however, continuously challenged by a number of non-isotopic techniques. This article reviews the measurement of europium chelates with high sensitivity using time-resolved fluorescence and its use as labels in immunoassays of protein and peptide hormones, haptens, virus antigens and for detection of inborn metabolic errors. It can be concluded that the time-resolved fluorescence detection of lanthanides and their chelates has been applied in a wide variety of both routine and research application. This technique is anticipated to gain wide use for measurement of numerous anylates of different origin. In immunoassays time-resolved fluorometry is one of the most promising alternatives available in the non-isotopic field.

Chelating Agents↗
PubMed1990

A beta 3 integrin mutation abolishes ligand binding and alters divalent cation-dependent conformation.

The ligand-binding function of integrin adhesion receptors depends on divalent cations. A mutant alpha IIb beta 3 integrin (platelet gpIIb/IIIa) that lacks ligand recognition shows immunologic evidence of a perturbed interaction with divalent cations. This was found to be caused by a G----T mutation that resulted in an Asp119----Tyr119 substitution in the beta 3 subunit. This residue is proximal to bound ligand and is in a conserved region among integrins that are enriched in oxygenated residues. The spacing of these residues aligns with the calcium-binding residues in EF hand proteins, suggesting interaction with receptor-bound divalent cation as a mechanism of ligand binding common to all integrins.

Amino Acid Sequence↗
PubMed1990

Evaluation of the worth of corynebacterium parvum in conjunction with chemotherapy as adjuvant treatment for primary breast cancer. Eight-year results from the National Surgical Adjuvant Breast and Bowel Project B-10.

During the 1970s, information obtained from animal tumor models and from patients with a spectrum of solid tumors indicated the worth of a variety of immunostimulating agents. These findings provided a biological and clinical rationale for conducting randomized trials to evaluate the worth of those agents. Consequently, in May 1977 the National Surgical Adjuvant Breast and Bowel Project (NSABP) implemented a randomized trial to determine whether Corynebacterium parvum (C. parvum, CP) plus chemotherapy would be more effective than chemotherapy alone in prolonging the disease-free survival (DFS) and survival (S) of patients with primary operable breast cancer and positive axillary nodes. The results of that trial through 8 years of follow-up fail to indicate that treatment with CP used in conjunction with l-phenylalanine mustard (L-PAM) plus 5-fluorouracil (PF) results in a better DFS and S than that observed after chemotherapy alone. Use of the immunomodulator has instead resulted in a poorer, but not statistically significant, outcome. Despite adjustments made to account for any imbalance in distribution of prognostic factors between the two treatment groups and despite considering treatment compliance as a factor, the unfavorable outcome persisted. A high incidence of fever and chills was associated with the administration of CP. The administration of hydrocortisone before each CP treatment reduced the frequency of those and other systemic effects. The failure to demonstrate a benefit from CP is in keeping with the failure of other nonspecific stimulating agents to contribute to the creation of a new paradigm for the treatment of breast cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Production and characterization of monoclonal antibodies to the glycosyl phosphatidylinositol-anchored lymphocyte differentiation antigen ecto-5'-nucleotidase (CD73).

A panel of monoclonal antibodies to the 69 kDa glycosyl phosphatidylinositol anchored lymphocyte differentiation antigen ecto-5'-nucleotidase (ecto-5'-NT, CD73) was produced using highly purified human placental 5'-NT as immunogen. Antibodies 1E9.28.1 and 7G2.2.11 inhibit soluble placental 5'-NT activity and recognize lymphocyte CD73 in indirect immunofluorescence and immunoprecipitation assays. In addition, 1E9.28.1 induces vigorous T cell proliferation in the presence of submitogenic doses of phorbol myristate and F(ab')2 goat anti-mouse Ig. Both antibodies can be used to purify the three major forms of placental 5'-NT by affinity chromatography. By two-color immunofluorescence, CD73 was found to be expressed on 19 +/- 5% of CD3+, 11 +/- 4% of CD4+, 51 +/- 14% of CD8+, 25 +/- 8% of CD28+, 15 +/- 5% of CD29+, 27 +/- 7% of CD45RA+, and 70 +/- 6% of CD19+ lymphocytes. Within T cells, CD73 expression is restricted to the CD28+ subset. Thus, CD73 is found on subsets of both T and B lymphocytes, with the highest expression on B cells and CD8+ T cells. In sections of hyperplastic tonsil, CD73 expression is restricted to the small lymphocytes of the follicular mantle zone, a small subset of extrafollicular lymphocytes situated within the epithelium of the tonsillar crypt, and to follicular dendritic cells within the lower part of the "light-zone." CD73 is also detected on subsets of endothelial cells of capillaries and venules and the basal layer of non-keratinizing squamous epithelium and transitional cell type mucosa of many tissues. Given the tissue distribution of CD73, along with its glycosyl phosphatidylinositol membrane anchoring and the observation that some CD73 antibodies are mitogenic, we propose that this interesting antigen may play a role in cell activation, lymphocyte homing, and/or cell adhesion.

5'-Nucleotidase↗
PubMed1989

Antibodies to 5'-nucleotidase (CD73), a glycosyl-phosphatidylinositol-anchored protein, cause human peripheral blood T cells to proliferate.

Human peripheral blood T cells were stimulated to proliferate when cultured with submitogenic doses of PMA and goat antibodies to 5'-nucleotidase (5'-NT). The degree of proliferation, as measured by [3H]TdR incorporation on day 3, was similar to that achieved by stimulation with PHA. Anti-5'-NT antibodies had no effect on PHA-induced proliferation. Maximal stimulation was achieved with 0.6 to 1.0 ng/ml of PMA and 125 micrograms/ml of IgG isolated from a goat anti-5'-NT antiserum. Both intact IgG and F(ab')2 fragments were stimulatory. IL-2R expression and IL-2 secretion were also induced by anti-5'-NT antibodies and PMA. Anti-5'-NT-induced proliferation was inhibited greater than 95% by a murine anti-IL-2 receptor mAb and required less than 0.3% monocytes. Similar results have been obtained with a murine mAb specific for 5'-NT. As expected, anti-5'-NT antibodies and PMA did not induce the proliferation of ecto-5'-NT-T cells isolated by cell sorting. Pretreatment of total T cells with phosphatidylinositol-specific phospholipase C removed an average of 89% of the 5'-NT activity from the cell surface and also inhibited by 83% the ability of the cells to proliferate in response to anti-5'-NT antibodies and PMA. Thus, the activation signal provided by anti-5'-NT antibodies is apparently transduced, in large part, by a form of the enzyme that is attached to the membrane via glycosyl-phosphatidylinositol linkage. These data suggest that 5'-NT may play a role in lymphocyte activation as has been proposed for other glycosyl-phosphatidylinositol-anchored lymphocyte surface proteins.

5'-Nucleotidase↗
PubMed1988

Postoperative adjuvant chemotherapy or BCG for colon cancer: results from NSABP protocol C-01.

Data are presented from 1,166 patients with Dukes B and C carcinoma of the colon who were entered into the National Surgical Adjuvant Breast and Bowel Project (NSABP) Protocol C-01 between November 1977 and February 1983. Patients were randomized to one of three therapeutic categories: 1) no further treatment following curative resection (394 patients); 2) postoperative chemotherapy consisting of 5-fluorouracil, semustine, and vincristine (379 patients); or 3) postoperative BCG (393 patients). The average time on study was 77.3 months. A comparison between patients receiving postoperative adjuvant chemotherapy and those treated with surgery alone indicated that there was an overall improvement in disease-free survival (P = .02) and survival (P = .05) in favor of the chemotherapy-treated group. At 5 years of follow-up, patients treated with surgery alone were at 1.29 times the risk of developing a treatment failure and at 1.31 times the likelihood of dying as were similar patients treated with combination adjuvant chemotherapy. Comparison of the BCG-treated group with the group treated with surgery alone indicated that there was no statistically significant difference in disease-free survival (P = .09). There was, however, a survival advantage in favor of the BCG-treated group (P = .03). At 5 years of follow-up, patients randomized to the surgery-alone arm were at 1.28 times the risk of dying as were similar patients treated with BCG. Further investigation disclosed that this survival advantage in favor of BCG was a result of a diminution in deaths that were non-cancer related. When analyses were conducted on which events not related to cancer recurrence were eliminated, the survival difference between the BCG and control groups became nonsignificant (P = .40); the cumulative odds at 5 years decreased from 1.28 to 1.10. The findings from this study are the first from a randomized prospective clinical trial to demonstrate that a significant disease-free survival and survival benefit can be achieved with postoperative adjuvant chemotherapy in patients with Dukes B and C carcinoma of the colon who have undergone curative resection.

Aged↗
PubMed1987

Cortical generators of the CI component of the pattern-onset visual evoked potential.

Thirteen-channel visual evoked potentials (VEPs) to pattern-onset were recorded with stimuli restricted to individual octants of the peripheral field, to halves and to quadrants of the fovea. The voltage of the CI component was measured in each channel to define its topography for each stimulated sector. The potential fields so obtained were then analysed to find the orientation and location of a dipole that would produce a corresponding pattern of voltages at the scalp. The locations of the computed dipoles are consistent with the hypothesis that CI is generated in striate cortex. The computed locations and orientations are not compatible with alternative arrangements of sources in extrastriate cortex. A significant problem remains. If CI is indeed generated by the striate cortex then the orientation of the dipoles excited by stimulation of the peripheral field indicates that the cortex is surface negative. This leads to the prediction that foveal stimuli will elicit a CI which is negative at posterior electrodes. The experiments reported here confirm that CI is positive with such stimuli, and its source is calculated as a horizontal dipole with its positive pole oriented posterolaterally. Two possible explanations are considered for the reversed polarity of foveal CI: (a) that macropotentials associated with stimulation of the fovea are opposite in polarity from those associated with stimulation of the peripheral field; (b) that the foveal area of the retinotopic map extends into the lateral calcarine fissure with the effect that much of it faces in the reverse direction from the cortex at the pole.

Adolescent↗
PubMed1985

Cyclophosphamide plus 5-FU versus 5-FU alone in advanced gastric carcinoma.

30 patients with advanced metastatic gastric adenocarcinoma, having a measurable indicator lesion, were randomized (1:2) to receive (intravenously) either weekly 5-fluorouracil alone (15 mg/kg) or combination treatment with cyclophosphamide (20 mg/kg) given on day 1 and 5-FU (15 mg/kg) given weekly on weeks 2-5, beginning on day 8. The combination cycle was repeated at 6-week intervals. Although the toxic effects of therapy were similar in both arms, the addition of cyclophosphamide to the single-agent 5-FU regimen did not increase either the frequency of objective response (5-FU 18%, combination 16%) or improve the median survival of patients with advanced measurable gastric carcinoma (5-FU 4.4 months, combination 5.2 months). Patients with pretreatment weight loss greater than 10% had significantly (p less than 0.05) shorter median survival (2.8 versus 5.6 months) compared to patients without weight loss.

Adenocarcinoma↗
PubMed1984

Hemispheric asymmetry of EEG alpha activation: effects of gender and familial handedness.

Twenty-four male and twenty-four female undergraduates took part in an experiment to investigate the effects of gender and familial handedness on hemispheric activation during numeric and visuospatial thinking. Each gender group was divided into twelve subjects with close left handed relatives and twelve subjects without. All subjects were overtly right handed. EEG alpha activity was recorded from left and right occipital and parietal regions with respect to mastoid references while the subjects performed numeric tasks with eyes open and with eyes closed, a face-recognition and a tactile-discrimination (figural-unification) task. EEG alpha power was quantified during these conditions and during relaxed wakefulness with eyes open and eyes closed. Relative activation, (suppression of alpha activity from rest) of left and right parietal regions during numeric and spatial tasks was found to depend upon gender and familial handedness. Males, not females, tended to switch from left hemisphere activation during face recognition. Irrespective of gender and to some extent of task, a tendency towards greater activation of the right hemisphere was associated with the possession of left handers among close relatives.

Adolescent↗
PubMed1984

Speed of work and EEG asymmetry.

EEG from O1 and O2 was recorded from twelve subjects (6 male and 6 female) whilst they carried out a paced inspection task at five separate task speeds. Peak alpha activity was analysed using a spectral analysis technique. The results suggested that when subjects were working at a speed 25% faster than their self-chosen pace they were using predominantly their right hemisphere, whereas then they were working at 25% slower they were using mainly their left hemisphere. It was suggested, based on earlier literature, that subjects may be processing information about the task in different ways at different task paces: A sequential processing strategy is being used at the slow pace whilst a parallel or Gestalt processing strategy is being used at the fast pace.

Adolescent↗
PubMed1984

Cognitive and EEG asymmetry.

Several recent reports concerning the relationship of EEG asymmetry to cognition were evaluated. Technical and interpretive shortcomings of some papers minimizes their significance with respect to this issue, whereas several findings support the notion that EEG asymmetry occurs in association with cognition per se.

Alpha Rhythm↗
PubMed1983

The prognostic significance of tumor location and bowel obstruction in Dukes B and C colorectal cancer. Findings from the NSABP clinical trials.

The present study examines the prognostic significance of tumor location and bowel obstruction in Dukes B and C colorectal cancer. Data were obtained from 1021 patients entered into two randomized prospective clinical trials of the NSABP. Tumor location proved to be a strong prognostic discriminant. Lesions located in the left colon demonstrated the most favorable prognosis. Tumors of the rectosigmoid and rectum had the worst prognosis with the relative risk of treatment failure for the latter being over three fold that of the left colon. When the relative risks associated with tumor location were adjusted for nodal imbalances, the left colon continued to demonstrate the most favorable prognosis. The presence of bowel obstruction also strongly influenced the prognostic outcome. Examination of the data without considering tumor location disclosed that patients with bowel obstruction were at greater risk for treatment failure than those without obstruction. The effect of bowel obstruction was influenced by the location of the tumor. The occurrence of bowel obstruction in the right colon was associated with a significantly diminished disease-free survival, whereas obstruction in the left colon demonstrated no such effect. This phenomenon was independent of nodal status and tumor encirclement, the latter two factors proving to be of prognostic significance independent of tumor obstruction. A multivariate analysis in which the covariate effects of sex, age, nodal status, tumor obstruction, encirclement, and tumor location were adjusted underscored the role of tumor location and obstruction as prognostic discriminants. The results indicate that the definition of prognostic factors can identify patient subsets with unique characteristics.

Carcinoma↗
PubMed1983

Hereditary costovertebral dysplasia with malignant cerebral tumour.

Costovertebral dysplasia comprises multiple malformations of the vertebrae and ribs, with a characteristic clinical picture of short trunk dwarfism, short neck, scoliosis, and rib cage deformity. We describe two sibs with the syndrome who are presumed to represent the autosomal recessive form of the disorder. One sib died from a malignant cerebral tumour and the association may be more than fortuitous.

Abnormalities, Multiple↗
PubMed1981

Asymmetries of the contingent negative variation (CNV) and its after positive wave (APW) related to differential hemispheric involvement in verbal and non-verbal tasks.

The CNV and the subsequent positive wave (including both the P300 wave and the slow positivity following it) were recorded at left and right frontal and central electrodes during the performance of tasks in which nine right-handed subjects (male and female) had to determine whether S1 and S2 were the same or different. In one task, works had to be matched for meaning while in a second, faces had to be matched for identity. Words elicited CNVs which were more negative over left than right frontal regions. This effect was reversed when the stimuli were faces. Since the CNV is presumed to reflect processes of anticipation rather than stimulus processing, the asymmetry cannot be explained in terms of the lateralisation of neural mechanisms specialised for the analysis of verbal or visuospatial stimuli. Instead the observation is regarded as evidence for mechanisms of lateral activation of a more general nature than would be necessary for the facultative selection of cognitive mode. The amplitude of the CNV relative to baseline was affected by the amplitude of P300 response to S1. This was larger to faces than words in both hemispheres. A small asymmetry in the positive wave following S2 was observed, the amplitude being greater over the right hemisphere for words and over the left for faces. This is interpreted in terms of the subjective probability of the two types of stimulus for a hemisphere ill-equipped to receive them.

Adult↗
PubMed1981

Conjugated estrogens and breast cancer risk in women.

The relationship between conjugated estrogen(s) (CE) and breast cancer was investigated by the examination of the records of 345 women with newly diagnosed breast cancer and 611 healthy controls belonging to a prepaid health plan. Use of CE was associated with a 40% elevation in risk [relative risk (RR) = 1.4; 95% confidence interval-1.0-2.0]. The RR was 1.3 for menopausal women with intact ovaries and 1.5 for those with ovaries removed. There was statistically significant evidence of a dose-response relationship with the three measures of dose evaluated. RR's rose to about twofold for women with 10 or more CE prescriptions noted in their charts, for those with 5 years or more between their first and last prescription, and for those with a usual daily dose of 1.25 mg or more. The RR associated with having ever used CE and with long-term use was highest among those women with a family history of breast cancer. These data support the hypothesis that long-term use of CE is associated with increased breast cancer risk.

Breast Neoplasms↗