Severe hypoventilation resulting from improper use of a disposable manual resuscitator.
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Cardiopulmonary Resuscitation↗
Biomedical subjects
G Freeman
Publications and source records attributed to G Freeman.
Differential up-regulation of the B7-1 and B7-2 costimulatory molecules after Ig receptor engagement by antigen.
Ag-pulsed B cells are potent APCs, in part, because of the ability of the Ig receptor to mediate rapid and specific Ag uptake. However, it is also known that full T cell activation requires signals delivered by costimulatory molecules, which naive B cells seem to lack. This study examines the effect Ig receptor engagement has on the expression and function of a new CD28 counter-receptor, B7-2. Unlike B7-1 (B7), B7-2 was rapidly induced on the cell surface of B cells after engagement of the Ig receptor by either anti-Ig mAbs or hen egg lysozyme (HEL) on normal and HEL-specific B cell receptor transgenic B cells, respectively. Furthermore, B7-2 expression was up-regulated on tolerant B cells isolated from HEL/anti-HEL double transgenic mice after Ag stimulation, although at lower levels than on nontolerant transgenic B cells. No significant cell surface levels of B7-1(B7) were observed under these conditions. Finally, the B7-2 molecules induced by Ig cross-linking costimulated T cell proliferation in a CD28-dependent manner, independent of B7-1(B7) expression. Thus, the effectiveness of Ag-specific B cells as APCs depends on both their enhanced Ag uptake, mediated by the B cell receptor, and immediate up-regulation of a potent costimulatory molecule, B7-2.
Animals↗
The role of intracellular calcium and pH during fertilization and egg activation in the hydrozoan Phialidium.
A calcium transient occurs at fertilization in the eggs of the hydrozoans Mitrocomella and Phialidium. The eggs of Phialidium have an intracellular pH (pHi) of 7.6-7.95. There is no increase in pHi following fertilization. Both calcium ionophore and ammonia treatments activate Phialidium eggs. Calcium ionophore causes a calcium transient without changing pHi. Ammonia concentrations of 10-20 mM at pH 8 cause a rise in pHi but no detectable calcium transient. Both activating agents can (1) block subsequent fertilization, (2) initiate cell cycle events such as DNA synthesis, nuclear envelope breakdown, chromosome condensation, and cleavage-related events, and (3) initiate voltage-dependent calcium channel function. While calcium ionophore treatment invariably elicits all of these manifestations of egg activation, ammonia sometimes induces only the induction of voltage-dependent calcium channel function. Oocytes were also treated with calcium ionophore or ammonia at different stages during their maturation. Ammonia treatment did not induce egg activation when applied at any stage during maturation; however, calcium ionophore initiated voltage-dependent calcium channel function when oocytes were treated after germinal vesicle breakdown. Ionophore treatment during maturation did not render these eggs unfertilizable or initiate cell cycle events. These experiments show that elevation of [Ca2+] with ionophore and increasing pHi with ammonia may activate these eggs through different pathways, that specific maturational events must occur before they can do so, and that the activation of voltage-dependent calcium channel function can be dissociated from other egg activation events.
Ammonium Chloride↗
Regional specification during embryogenesis in the articulate brachiopod Terebratalia.
The timing of regional specification during embryogenesis in Terebratalia transversa has been examined by isolating animal, vegetal, and lateral halves at developmental stages ranging from prior to fertilization through late gastrula. Animal halves isolated from prior to fertilization through late blastula stages did not gastrulate and did not form endoderm. When these animal halves were isolated from prior to fertilization through early blastula, they formed only ciliated vesicles; however, similar halves from late blastulae frequently formed the ectodermal components of the three larval lobes. Vegetal halves isolated prior to fertilization through late blastula gastrulated, formed endoderm, and differentiated most larval structures; however, comparable isolates from late gastrulae showed a marked decline in the ability to form anterior larval structures. Animal halves isolated at this stage showed a corresponding decline in the ability to form posterior larval structures. These results indicate that during oogenesis, regional differences arise so that the animal half of the oocyte has a much greater ability to form anterior ectodermal structures than do other regions of the oocyte, while only the vegetal region has the capacity to gastrulate. Inductive signals produced by the vegetal region of the embryo act on the animal half to give it the capacity to form ectodermal components of the three larval lobes. This vegetal-inductive influence has played a major role in regional specification by the late blastula stage of development. Pairs of lateral halves isolated from the same oocyte or embryo from prior to fertilization through late blastula frequently gastrulate, form endoderm, and proceed to form all or most of the larval lobes. The late blastula is the first developmental stage where there is a marked decline in the ability of pairs of lateral halves to differentiate larval structures and is the first stage where pairs of halves resembling dorsal and ventral halves appear. This suggests that the axis of bilateral symmetry is also specified by the late blastula stage of development.
Alkaline Phosphatase↗
Ineffectiveness of AIDS education and HIV antibody testing in reducing high-risk behaviors among injection drug users.
The effectiveness of education in reducing high-risk human immunodeficiency virus (HIV) transmission behaviors was examined in 313 injection drug users. Involvement in high-risk behaviors was assessed via structured interview at study entry and 4 months following the intervention. Subjects were randomly assigned to (1) AIDS education, (2) AIDS education with optional HIV antibody testing, or (3) a wait list. The sample as a whole decreased its involvement in high-risk behaviors, but there were no significant differences as a function of experimental group assignment.
AIDS Serodiagnosis↗
All advanced stage non-Hodgkin's lymphomas with a polymerase chain reaction amplifiable breakpoint of bcl-2 have residual cells containing the bcl-2 rearrangement at evaluation and after treatment.
Polymerase chain reaction (PCR) of bcl-2 provides an extremely sensitive method to detect minimal disease in approximately 50% of patients with non-Hodgkin's lymphomas (NHL). In an attempt to determine the clinical usefulness of this technique, we examined the bone marrow (BM) of 152 patients with advanced-stage NHL at the time of evaluation and after induction or salvage chemotherapy before autologous BM transplantation. The BM proved to be an accessible and reproducible tissue source to determine PCR positivity because all of the 102 patients examined had the same PCR-amplifiable breakpoint in their BM and lymph node. At the time of evaluation, PCR analysis in advanced-stage NHL patients added little additional information to morphologic analysis because each technique identified BM infiltration in approximately 70% of patients. PCR was significantly more useful in determining BM infiltration after induction or salvage therapy. At that time, approximately 50% of patients had morphologically normal BM, whereas PCR analysis remained positive in 100% of those with an amplifiable breakpoint. These observations were confirmed in a clinical trial attempting to induce remission in previously untreated low-grade advanced-stage NHL patients. In this series, PCR was positive in all patients after treatment although the BM was histologically uninvolved in 50% of cases, showing that conventional therapy did not eradicate bcl-2-positive cells.
Antineoplastic Combined Chemotherapy Protocols↗
Follicular dendritic cells contain a unique gene repertoire demonstrated by single-cell polymerase chain reaction.
Follicular dendritic cells (FDCs) form a dense network between B cells within the germinal center and are thought to be an important component of this B-cell microenvironment. Previous immunophenotypic studies have been inconclusive in determining the cellular origin of FDCs. Gene coexpression within individual and highly enriched FDCs was determined using polymerase chain reaction. FDCs contain a very restricted mRNA pattern with high levels of message for the C3d receptor (CR2, Epstein Barr-virus/EBV receptor, CD21) and lack of mRNA for CD20, CD45, CD4, fibronectin, and platelet-derived growth factor receptor alpha and beta. These observations are consistent with the hypothesis that FDCs may not be of classical hematopoietic or fibroblastic origin. The absence of interferon-gamma, tumor necrosis factor-alpha, interleukin-3, and interleukin-6 mRNA provides preliminary evidence that these cells might produce only a very restricted set of cytokines limited to the germinal center.
Antigens, CD↗
The bases for and timing of regional specification during larval development in Phoronis.
A fate map has been constructed for Phoronis vancouverensis. The animal pole of the egg gives rise to the apical plate in the hood of the actinotroch larva. The vegetal pole of the egg marks the site of gastrulation. During the initiation of gastrulation the cells of the animal pole of the embryo are directly opposite those at the vegetal pole of the embryo. The plane of the first cleavage always goes through the animal-vegetal pole of the egg. In about 70% of the cases the plane of the first cleavage is perpendicular to the future anterior-posterior axis of the actinotroch larva; in the remaining cases the plane of the first cleavage is either oblique with reference to, or occurs along, the future anterior-posterior axis of the larva. Following gastrulation catecholamine-containing cells first make their appearance in the apical plate and gut cells first produce esterase. The timing of regional specification in these embryos has been examined by isolating animal or vegetal, anterior or posterior, or lateral regions at different time periods between the initiation of cleavage and gastrulation and examining their ability to differentiate. Animal halves isolated from early cleavage through late blastula stages do not gastrulate and do not form catecholamine-containing cells. When animal halves are isolated with endoderm during gastrulation, they differentiate catecholamine-containing cells. Vegetal halves isolated at the 8- to 16-cell stage gastrulate and form normal actinotroch larvae with esterase-positive gut and catecholamine-containing apical plate cells. When this same region is isolated at blastula stages it does not gastrulate and does not differentiate these cell types. Vegetal halves isolated during gastrulation subsequently form esterase-positive gut cells, but they do not form catecholamine-containing apical plate cells. When presumptive anterior, posterior, or lateral halves are isolated from early cleavage through blastula stages, each half forms a normal actinotroch larva. Lateral halves isolated during gastrulation also form normal larvae. Anterior halves isolated during late gastrulation differentiate only the anterior end of the actinotroch larva. These isolates have a hood with catecholamine-containing apical plate cells and the first part of an esterase-positive gut but lack the anlagen of the intestine and protonephridia. Posterior halves isolated during late gastrulation differentiate only the posterior end of the actinotroch which lacks a hood with catecholamine-containing cells but has an esterase-positive gut, protonephridia, and the anlagen of the intestine.(ABSTRACT TRUNCATED AT 400 WORDS)
Animals↗
Needle-use practices among intravenous drug users in an area where needle purchase is legal.
Needle-use practices of intravenous drug users (IVDUs) were examined in a region (Seattle, King Country, Washington State, USA) where needle purchase is legal. IVDUs in treatment (n = 313) were administered extensive structured interviews concerning drug and injection equipment-use practices. Of the 80.2% reporting intravenous drug use in the previous year, 78.3% reported sharing needles. Of the 47.7% reporting intravenous use in the previous 30 days, only 40.5% shared needles, with 59.3% sharing with only one other person. Most needle-sharing partners were very well known (63%) or well known (17%) to the subjects. The most frequent method for obtaining needles was 'buying in a drug store', ranked first by 65% of the sample. Subjects whose primary source was 'buying in a drug store' shared equipment less frequently during drug-use events in the previous year (mean: 16.2%) than those with other primary sources (mean: 28.5%). Compared with findings from other regions where needle purchase and possession are illegal without a prescription, fewer subjects in the current investigation shared needles, and those who did shared with a smaller number of people. The apparent association between legalized injection equipment and reduced sharing of equipment among IVDUs should be further examined in longitudinal studies of needle-sharing before and after legalization is instituted.
Adult↗
Sexual behaviors of intravenous drug users in treatment.
Sexual behaviors of a group of 313 intravenous drug users (IVDUs) (225 men, 88 women) were assessed by a structured interview at the start of an AIDS prevention project. Although the majority were celibate or monogamous during the prior year (men 52.5%, women 64.3%), many IVDUs had multiple sexual partners in that time, including 19.6% of men and 7.2% of women reporting five or more. Married male and female IVDUs were more likely to have multiple sexual partners than married people in general population samples. Only 38.5% of male and 35.4% of female IVDUs ever used condoms during the previous 5 years. Percentage of sexual encounters in which condoms were used correlated significantly with the number of partners for women (r = 0.37, p less than 0.01), but not for men (r = 0.03, ns). Use of intravenous drugs in the prior year, sharing of needles, use of stimulants, exchange of sex for money or drugs, and combining sexual events with drug use were all associated with greater numbers of sexual partners. A subset of male IVDUs engages in the dual-risk behaviors of needle sharing and unprotected intercourse with multiple partners. This group could act as a highly efficient vector for human immunodeficiency virus transmission and should become a focus of intensive preventive intervention.
Acquired Immunodeficiency Syndrome↗
Acute effects of aspartame on concentrations of brain amines and their metabolites in selected brain regions of Fischer 344 and Sprague-Dawley rats.
This study is the first in a series to define a rodent model to document the effects of amino acid-modulating compounds on central neurotransmitter function. A time-response curve for a single dose of orally intubated aspartame was determined in male Fischer 344 and Sprague-Dawley rats. Regional brain concentrations of norepinephrine (NE), dopamine (DA), serotonin (5-HT) and their metabolites were analyzed in the hypothalamus, cerebellum, pons/medulla, hippocampus, striatum, cortex, and midbrain/thalamus at 30, 60, 120, or 240 min after oral aspartame (1000 mg/kg) administration. Without consideration for time and group variables, levels of most compounds were higher in the brain regions of Fischer than Sprague-Dawley rats. Aspartame in Fischer 344 or Sprague-Dawley rats had no significant effect on levels of the catecholamines or indoleamines at any of the time points monitored following its acute administration. From the results of this study, large oral loads of aspartame do not appear to lead to regional alterations in brain biogenic amine levels.
3,4-Dihydroxyphenylacetic Acid↗
Effects of education on high risk HIV transmission behaviors.
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Acquired Immunodeficiency Syndrome↗
mAb 104, a new monoclonal antibody, recognizes the B7 antigen that is expressed on activated B cells and HTLV-1-transformed T cells.
A new monoclonal antibody (mAb) of the IgG1 subclass, mAb 104, has been obtained after immunization of mice with the Burkitt lymphoma cell line Jijoye. It only weakly binds to a small proportion of non-activated normal B cells and binds to a larger proportion of in vitro-activated normal B cells. All tested Epstein-Barr virus (EBV)-transformed B-cell lines, Burkitt lymphoma cell lines and freshly isolated follicular B-lymphoma cell preparations strongly bound mAb 104. mAb 104 did not bind to peripheral monocytes or tested myelomonocytic cell lines, or to resting and activated normal T cells, T-cell lines and T-cell clones. However, the recognized antigen is expressed on HTLV-1-infected T-cell lines and HTLV-1-transformed T-cell clones. mAb 104 immunoprecipitates, from Jijoyce cell lysates, a single polypeptide with an apparent MW of 45,000-60,000 and an isoelectric point of 5.6. Competition studies with the anti-B7 antibody (Freedman et al., 1987) demonstrated that mAb 104 and the anti-B7 block each others' binding. Furthermore, mAb 104 binds to transfected COS cells (Freedman et al., 1989) expressing the B7 antigen. Thus mAb 104 and and anti-B7 define the same antigen. The restricted distribution of the 104/B7 antigen to activated B cells and HTLV-1-transformed T cells may make it a useful marker for the study of pathological states linked to lymphocyte activation and for the functional study of B-cell subpopulations.
Antibodies, Monoclonal↗
Definition of T-cell specific DNA-binding factors that interact with a 3'-silencer in the CD4+ T-cell gene Rpt-1.
Analysis of the region 3' to the CD4+ T-cell gene Rpt-1 (encoding regulatory protein T-lymphocyte 1) led to the definition of a silencer element that inhibits heterologous gene expression in certain CD4+ T-cell lines but not in B-cell or non-lymphoid cell lines. Functional silencer activity in vivo was associated with the presence of a specific silencer-DNA-protein complex in electrophoretic mobility shift assays with T-cell extracts. Formation of this complex was selectively inhibited by the region in HIV-1 containing a silencer element. We discuss the possibility that DNA-binding factors may coregulate HIV-1 and Rpt-1 gene expression through a common transcriptional silencer element.
Amino Acid Sequence↗
Activation primes human B lymphocytes to respond to heat shock.
Crosslinkage of the B cell antigen receptor by anti-mu beads or SAC results in the selective induction of hsp70. We have observed that activated cells, having enhanced expression of hsp70, survive lethal stimuli much better than their unactivated counterparts. These results are in accordance with the proposal that hsp70 is essential for cells to survive lethal environmental stresses. Moreover, the activation event itself primes B cells thereby enabling them to increase the expression of both hsp70 mRNA and protein. This is the first demonstration that triggering of B cells via crosslinkage of sIg is accompanied by the induction of thermotolerance without the need for a prior sublethal heat treatment.
B-Lymphocytes↗
Isolated human follicular dendritic cells display a unique antigenic phenotype.
In the present study, follicular dendritic cells (FDCs) were purified to homogeneity in order to define the lineage and function of these cells. FDCs were identified by their characteristic morphology and by their expression of receptors for the third complement component, the myeloid-restricted antigen CD14, and the FDC antigen DRC-1. Unclustered FDCs displayed a unique antigenic phenotype since they expressed several B- and myeloid lineage-restricted antigens, but lacked T and NK cell antigens as well as the leukocyte common antigen. FDCs expressed adhesion molecules, including most of the VLA proteins, intercellular adhesion molecule 1 (ICAM-1), and CD11b. FDCs could be isolated to homogeneity by their intense staining with anti-CD14 using flow cytometric cell sorting. These highly purified FDCs expressed CD14 and CD21 but lacked CD20. This antigen pattern and characteristic morphology confirmed that these cells were, in fact, homogeneous FDC preparations. Analysis of polymerase chain reaction-amplified cDNA from highly purified FDCs showed no transcripts for IL-6. The isolation of homogeneous FDC populations will be important for the analysis of the functional role of FDCs within the lymphoid follicle.
Antigens, Differentiation↗
GPs' differing responses to out-of-hours calls.
After noticing trainer-trainee differences in the proportion of patients visited, a three-month audit of all out-of-hours requests and calls was performed. A wide variation of response was found among doctors on the rota. Those more likely to visit were also more likely to prescribe. A large proportion of the user population was either very young or very old and had an annual consultation rate nearly three times the mean for the practice as a whole.
Adult↗