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N Jacobs

Publications and source records attributed to N Jacobs.

At least 37 records · Page 2Linked to original sources
PubMed1996

Improved four-color flow cytometry method using fluo-3 and triple immunofluorescence for analysis of intracellular calcium ion ([Ca2+]i) fluxes among mouse lymph node B- and T-lymphocyte subsets.

A visible-light, dual-laser, flow cytometric method was developed for the simultaneous analysis of intracellular ionized calcium concentration ([Ca2+]i) and three cell-surface markers (CD4, CD8, and Thy-1.2 antigens) by using the calcium probe fluo-3 and using R-phycoerythrin (PE), peridinin chlorophyll-alpha protein (PerCP), and allophycocyanin (APC) conjugated monoclonal antibodies (MoAbs). This improved method was used in the analysis of [Ca2+]i mobilization upon in vitro stimulation with mitogenic lectins [phytohaemagglutinin (PHA) or concanavalin A (ConA)], anti-CD3 MoAbs, or A23187 calcium ionophore in the heterogeneous lymph node cell populations from healthy C57BL/Ka mice. The present results show that the calcium responses were heterogeneous and dependent on the cellular immunophenotype, not only on lectins or anti-CD3 MoAbs stimulation, but also on the receptor-independent A23187 ionophore stimulation. An in situ fluo-3 calibration method (using A23187 and metabolic poisons in Ca2+ /EGTA buffers with known free calcium concentrations) indicated a resting [Ca2+]i in lymphocytes of 103 +/- 23 nM (mean +/- S.D.) but with significant differences between the [Ca2+]i in B cells and in all of the T-cell subsets (CD4+Thy-1+, CD4+Thy-1-, and CD8+T cells). Both the B cells and the T-cell subsets showed an increase of fluo-3 fluorescence upon in vitro stimulation with ConA or PHA, but the calcium mobilization following lectin stimulation was time delayed in all T-cell subsets. Only the T cells, including the CD4+Thy-1- subset, responded to anti-CD3 MoAbs. The percentage of responding cells upon stimulation with ConA was higher in T cells than in B cells. By contrast, PHA gave a higher response in B cells. After stimulation with different mitogens, [Ca2+]i increased in both CD4+ and CD8+ T-cell subsets. However, the percentage of responding cells was far higher in the CD4+Thy-1+ subset than in the CD4+Thy-1- or the CD8+T-cell subsets. The stimulation with A23187 ionophore induced a higher calcium response in B cells than in T cells. Interestingly, it also induced greater Ca2+ mobilization in CD4+ than in CD8+T cells. These results demonstrate the potential use of fluo-3 simultaneously with three fluorescein (FITC)-compatible fluorochromes. This technique may be useful for investigating the role of the CD4+Thy-1-T cells, a rare subset that is abnormally expanded in a murine acquired immunodeficiency syndrome (murine AIDS).

Aniline Compounds↗
PubMed1996

Identification of prostanoid receptors in rabbit non-pigmented ciliary epithelial cells.

Preliminary ligand binding studies demonstrated that the membrane preparations of the rabbit nonpigmented ciliary epithelial cell line have 3H-prostaglandin E2 binding sites. The binding sites were specific for 3H-prostaglandin E2 as demonstrated by competition with unlabeled prostaglandin E2. The IC50 of prostaglandin E2 for the inhibition of 3H-prostaglandin E2 binding was 435 nM. The stimulation of adenylyl cyclase and phospholipase C by prostanoid receptor agonists, in rabbit non-pigmented ciliary epithelial cells resulted in the formation of either cyclic AMP or inositol phosphates. Prostaglandin E2 and 16-16-dimethyl prostaglandin E2 (both are EP1, EP2, EP3 and EP4 receptor agonists). 11-deoxy prostaglandin E1 (EP2, EP3 and EP4 receptor agonist), butaprost (EP2 receptor agonist), and prostaglandin D2 (DP receptor agonist) stimulated the formation of cyclic AMP in a dose-dependent manner. Maximal stimulation occurred between 1.25 and 2.5 microM for prostaglandin E2 and 16,16-dimethyl prostaglandin E2 and between 10 and 20 microM for 11-deoxy prostaglandin E1 and prostaglandin D2. Prostaglandin E2 and 16,16-dimethyl prostaglandin E2 were more potent (EC50 of 0.25 microM and 0.42 microM respectively) than 11-deoxy prostaglandin E1, butaprost or prostaglandin D2. The formation of cyclic AMP by prostaglandin D2 was inhibited by BW868C, a highly selective DP receptor antagonist. 17-phenyl trinor prostaglandin E2, prostaglandin F2 alpha and U46619, the EP1, FP and TP receptor agonists, respectively stimulated phospholipase C (as measured by the formation of total inositol phosphates) in a dose-dependent manner. The agonists 11-deoxy prostaglandin E1 and butaprost coupled to adenylyl cyclase via guanine nucleotide binding protein, G8, did not increase the turnover of inositol phosphates. The results of the present study suggest that rabbit non-pigmented ciliary epithelial cells express EP1, EP2, DP, FP and TP receptors.

Adenylyl Cyclases↗
PubMed1996

Further characterization of cytotoxic T cells generated by short-term culture of human peripheral blood lymphocytes with interleukin-2 and anti-CD3 mAb.

In this study we have specifically investigated the participation of T cells in the cytotoxic activity of peripheral blood lymphocytes (PBL) activated by interleukin-2 (IL-2, 50 U/ml) alone or in combination with an anti-CD3 mAb (BMA030, 10 ng/ml, IgG2a). Purified CD3+ T cells, incubated in the presence of the anti-CD3 mAb for 4 days, mediated a cytotoxic activity against HL60 and U937 tumor cell lines. Several findings suggested the involvement of a redirected-cytotoxicity phenomenon, since the lytic process was restricted to target cell lines bearing the high-affinity Fc gamma receptor (Fc gamma RI) and T lymphocytes stimulated by IL-2 alone did not lyse these cell lines. Furthermore, anti-CD3 mAb F(ab')2, anti-CD3 IgG1 (UCHT1), phytohemagglutinin or staphylococcal enterotoxin A did not induce a similar cytotoxic activity in T lymphocytes. The cytotoxic process occurred in the presence of a very low level of anti-CD3 antibodies (in the nanomolar range). The cytotoxic activity of T cells stimulated by IL-2 or by IL-2 + BMA030, against OVCAR-3 cells (MOv18+ ovarian tumor cell line), was also compared in the presence of a bispecific antibody OC/TR, anti-CD3 x MOv18). The stimulation by IL-2 + BMA030 induced approximately a twofold higher cytotoxic activity than IL-2-activated T cells. This could be related to the state of activation of effector cells stimulated by IL-2 + BMA030, since the phenotypic analysis showed an increased proportion of T cells expressing several activation/differentiation markers (CD25, HLA-DR, CD45R0, adhesion molecules). These findings could be applied to the design of therapeutic protocols using anti-CD3 x antitumoral bispecific antibodies.

Antibodies, Bispecific↗
PubMed1996

Fibrinogen binding to ICAM-1 on EA.hy 926 endothelial cells is dependent on an intact cytoskeleton.

Fibrinogen is a ligand for Intercellular Adhesion Molecule-1 (ICAM-1), and enhances monocyte-endothelial cell interaction by coupling Mac-1 on monocytes to ICAM-1 on endothelial cells. We investigated the role of the cytoskeleton in fibrinogen binding to the human endothelial cell line EA.hy 926 using immunofluorescence techniques. In this cell line TNF alpha induced the simultaneous appearance of stress fibers and of ICAM-1, which was clustered predominantly on endothelial cell projections. Incubation of TNF alpha-stimulated endothelial cells with fibrinogen resulted in binding of fibrinogen to ICAM-1 on these cell projections. Disruption of the cytoskeleton by cytocholasin B abolished fibrinogen binding. Activation of protein kinase C with 12-O-tetradecanoyl phorbol-13-acetate resulted in simultaneous loss of both stress fibers and fibrinogen binding. These results suggest that a connection between ICAM-1 and the cytoskeleton results in clustering of ICAM-1 on cell projections, which is required for fibrinogen binding.

Cell Line↗
PubMed1995

Quantification of blood echogenicity: evaluation of a semiquantitative method of grading spontaneous echo contrast.

Spontaneous echo contrast (SEC) is an echogenic, swirling pattern of blood flow which may be observed by transesophageal echocardiography (TEE) in the left atrium in low flow states, such as atrial fibrillation (AF). The presence of SEC has been proposed as a marker of increased thromboembolic risk. Evaluation of the severity of SEC might be useful in stratification of thromboembolic risk. The aim of this study was to validate a semiquantitative method of grading SEC against quantitative videodensitometric analysis. TEE studies were performed in 50 patients with AF. The severity of left atrial SEC was graded by three independent observers and by videodensitometry. There was a strong, positive correlation between the semiquantitative grades of SEC and quantitative videodensitometric scores (r = 0.85, P < 0.0001). Inter- and intraobserver correlations in the grading of SEC were very high (observer 1 vs. 2: r = 0.98, P = 0.0001; observer 1 vs. 3: r = 0.93, P = 0.0001; observer 1 vs. 1: r = 0.97, P = 0.0001). Semiquantitative grading of SEC can be performed rapidly and reliably by experienced observers. These results support the use of semiquantitative grading in studies of the pathogenesis and prognostic implications of SEC.

Adult↗
PubMed1994

Measles antibody titers in early infancy.

OBJECTIVE: To determine the prevalence of measles seronegativity among infants younger than 6 months and to ascertain their serologic response to measles vaccine. DESIGN: Cross-sectional measles antibody survey during the 1989 measles epidemic in Chicago, Ill. SETTING: Inner-city perinatal center. PARTICIPANTS: Two hundred three infants younger than 6 months who had been admitted to the neonatal intensive care unit at birth; 130 (64%) of these infants were premature. Transplacental antibody transfer was evaluated in a subset of 89 mother-newborn pairs. INTERVENTION: Administration of measles monovalent vaccine to seronegative infants. MEASUREMENTS/RESULTS: Measles IgG antibody was measured using indirect fluorescent assay. At birth, 19 (38%) of 50 neonates born at less than 37 weeks' gestation had antibody titers that were twofold to fourfold lower than those of their mothers compared with three (8%) of 39 neonates born at more than 37 weeks' gestation (P < .01). Of the 203 study infants, fewer than 4% were seronegative at birth, while 74% of these infants aged 4 to 5 months were seronegative. Univariate logistic regression analysis indicated that the independent variables related to seronegativity were as follows: gestational age at birth (P = .007), chronological age (P < .001), history of having received three or more packed red blood cell transfusions (P < .001), and maternal age at delivery (P = .001). Multiple logistic regression analysis confirmed the association of seronegativity with chronological age (P < .001), gestational age (P < .02) and maternal age at delivery (P < .001). Seroconversion following administration of the measles vaccine was documented in 11 (79%) of 14 infants. CONCLUSION: A significant proportion of 4- to 5-month-old infants who had been admitted to the neonatal intensive care unit at birth lack measurable measles antibody; this population should be taken into account when strategies to control measles are considered.

Adolescent↗
PubMed1993

Efficient immunoselection of cytolytic effectors with a magnetic cell sorter.

This paper describes a rapid and efficient method for the sorting of in vitro activated cytolytic effectors cells. For cytotoxic assays, a large number of cells with conserved function must be rapidly obtained. Immunomagnetic sorting was chosen because it is faster than flow cytometry sorting. The MACS system requires the use of paramagnetic beads of small diameter (100-150 nm), reputed to interfere minimally with cell function. In order to generate the cytolytic effectors, peripheral blood lymphocytes were cultivated in the presence of interleukin-2 (50 U/ml) and anti-CD3 monoclonal antibody (BMA030, 100 ng/ml) for 4 days. Cell separation was based on the membrane expression of the CD3 complex. The purity obtained for positive (CD3+) cell sorting with the MACS was higher than 95%. The purity of negative (CD3-) cell fraction was more variable, but further purification by flow cytometry rapidly yielded purity higher than 95%. Cytotoxic assays were performed against four target cell lines (K562, Daudi, HL60 and U937) and proliferation assays showed that both negatively and positively selected populations had conserved their function acquired during culture in the presence of anti-CD3 mAb and IL2.

Antibodies, Monoclonal↗
PubMed1990

Graft-versus-host disease associated T helper cell responses specific for minor histocompatibility antigens are mainly restricted by HLA-DR molecules.

Graft-versus-host reactions are mediated by subpopulations of donor T cells and can be attributed to host specific minor histocompatibility (mH) antigens. We isolated strong anti-host mH antigen proliferative T cell lines, LG2, PN2, and LH3, from three patients suffering from acute graft-versus-host disease (GVHD). To study the role of the different major histocompatibility complex (MHC) molecules in the anti-host mH antigen specific proliferative response, the reactivities of the three T cell lines were analysed in primed lymphocyte test (PLT) assays against panels of stimulator cells obtained from unrelated blood donors. LG2 and LH3 stimulating determinants were commonly detected in the unrelated panel, whereas the PN2 T cell line recognized a rare specificity. The responses were associated with the presence of self HLA-DR molecules on the stimulator cells, although not all DR sharing stimulator cells were recognized. The proliferative responses of LG2, LH3 and PN2 cells could be blocked by monoclonal antibodies (MoAbs) against HLA-DR, but not by MoAbs against HLA-A/B/Cw, HLA-DQ or -DP. At the responder cell level, depletion of CD4 cells as well as blocking with CD4 specific MoAbs abrogated the specific responses of the three T cell lines. Our findings suggest that anti-host Th cell responses activated in the acute phase of GVHD are directed against both frequent and rare mH antigens, are mediated by CD4 + ve class II restricted Th cells, and use the HLA-DR molecule as a common restriction element for mH antigen presentation.

Acute Disease↗
PubMed1988

Continuing experience with the fetal acoustic stimulation test.

Antepartum fetal heart rate testing remains a useful method with which to assess fetal well-being in high-risk pregnancies. Recently the adjunctive use of transabdominal acoustic stimulation was proven effective in reducing the number of nonreactive nonstress tests (NSTs) without changing the predictive reliability of the test. Our continuing experience with this method involved 1,503 women undergoing 3,935 tests. A reactive test occurred in 93%, and the fetal death rate was 1.3/1,000. In an attempt to evaluate the incidence of mortality in a large population, data from the current investigation were pooled with those from other reports from our institution. In our aggregate experience of 7,763 tests, fetal death occurred within seven days of a reactive test with an incidence of 1.9/1,000 in patients receiving acoustic stimulation. This finding contrasts favorably with a death rate of 1.6/1,000 in fetuses with spontaneous reactivity. Fetal acoustic stimulation testing seems to offer advantages over the more traditional NST, and the predictive values of normal tests seem to be equivalent.

Acoustic Stimulation↗
PubMed1987

Antepartum fetal surveillance in the patient with decreased fetal movement.

Whenever a patient has the subjective perception of decreased fetal movement, prompt evaluation in the form of antepartum fetal surveillance has been undertaken. The purpose of this report is to describe our experience with 489 pregnant women who came between Jan. 1 and Dec. 31, 1985 to our Antepartum Fetal Surveillance Clinic with this complaint alone or in association with another indication for fetal surveillance. Overall, 838 nonstress tests were performed, and the results were reactive, 93.2%; nonreactive, 6.8%; and fetal heart rate decelerations, 6.1%. Comparison of the first nonstress test results between those with decreased fetal movement alone or in combination with another diagnosis demonstrated a similar incidence of nonreactivity and fetal heart rate decelerations. In those patients whose indication was decreased fetal movement alone, there was a 3.7 times greater likelihood of diminished amniotic fluid volume. When the last test within 7 days of delivery was analyzed, the decreased fetal movement alone group had a lower incidence of cesarean delivery, cesarean delivery for fetal distress, and Apgar scores less than 7 than patients with an additional indication for testing. In summary, decreased fetal movement continues to be an acceptable indication for fetal surveillance. Based on our retrospective experience, the most reasonable approach appears to be a combination of nonstress test and amniotic fluid volume assessment. Unless the patient has additional indications for fetal surveillance, the patient with decreased fetal movement with a reactive nonstress test and a normal amniotic fluid volume does not appear to warrant additional testing.

Amniotic Fluid↗
PubMed1987

The four-quadrant assessment of amniotic fluid volume: an adjunct to antepartum fetal heart rate testing.

Amniotic fluid volume assessment using a semiquantitative four-quadrant technique, the amniotic fluid index, was evaluated in relationship to fetal heart rate (FHR) testing and perinatal morbidity in 330 high-risk pregnancies. An inverse relationship was found between the amniotic fluid index and nonreactive nonstress tests (NST), FHR decelerations, meconium staining, cesarean section for fetal distress, and low Apgar scores. More important, adverse perinatal outcome was significantly more frequent with diminished compared with normal amniotic fluid volume, even if the NST was reactive.

Amniotic Fluid↗
PubMed1985

Pupil size in relation to ultrasonic anterior chamber depth measurements in pseudophakic eyes.

The effect of pupil size on ultrasonically determined anterior-chamber depth was studied in vitro with the Storz Alpha 20/20 and with the Kretz ultrasonoscope at high and low system sensitivity. The traces were measured peak to peak and base to base; results were compared to anterior-chamber depth measurements with optical pachymetry. We conclude that when measuring anterior-chamber depth with ultrasound, the pupil must be fully dilated or reduced system sensitivity must be used and the traces measured peak to peak.

Aged↗
PubMed1985

Efficacy in anterior uveitis of two known steroids and topical tolmetin.

We have compared the anti-inflammatory efficacy of 5% tolmetin sodium dihydrate, 0.5% prednisolone disodium phosphate, and 0.1% betamethasone disodium phosphate in 71 consecutive patients presenting with acute endogenous non-granulomatous uveitis randomly assigned to one of these treatment groups. Inflammatory symptoms and signs were scored during the course of the 21-day trial period. There was no statistically significant difference in the effect on the signs or symptoms of the three drugs tested. 90% of the Betnesol (betamethasone sodium phosphate, benzalkonium chloride) treated group were clinically judged cured compared with 68% of the Predsol (prednisolone sodium phosphate, benzalkonium chloride) treated group, and 57% of the tolmetin treated group.

Administration, Topical↗
PubMed1985

Timolol and guanethidine plus adrenaline in combination in the treatment of chronic open angle glaucoma.

A four month study was conducted in patients with chronic open angle glaucoma to determine whether timolol and guanethidine plus adrenaline have an additive effect in lowering intraocular pressure. Thirty-five patients were assigned to four treatment sequences (timolol 0.25 per cent and 0.5 per cent supplemented with guanethidine 1 per cent plus adrenaline 0.2 per cent (Ganda 1.0/0.2) and vice-versa). There was a significant reduction in intraocular pressure after one month's combined therapy in three of the four treatment groups but this reduction was maintained in only one group (timolol 0.5 per cent with Ganda 1.0/0.2) after four months therapy. The results are discussed with particular reference to adrenergic influences on aqueous humour dynamics.

Aged↗