Criteria for studies of antibiotic therapy for acute otitis media.
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Acute Disease↗
Biomedical subjects
R H Schwartz
Publications and source records attributed to R H Schwartz.
LSD. Its rise, fall, and renewed popularity among high school students.
LSD is making a comeback nationwide among Caucasian middle-class high school and college students. Compared to the mean values during the years 1985 to 1990, an approximately 25% increase occurred in lifetime-, annual-, and monthly-use rates of LSD, in 1993, according to the annual NIDA high school senior survey. In 1992, an increase in LSD-related arrests occurred, as did seizures of larger quantities of consumer-ready LSD. The number of LSD-related emergency room visits by adolescents increased, and intermittent LSD-related violent behavior, including suicide, homicide, and accidental death, were higher than in the previous 5-year period. Fewer high school students attribute great danger in trying LSD once or twice. The painfully learned lessons about LSD seem, sadly, destined to be relearned by the youth of the 1990s.
Adolescent↗
Regulation of interleukin 2 gene expression by CD28 costimulation in mouse T-cell clones: both nuclear and cytoplasmic RNAs are regulated with complex kinetics.
T-cell receptor (TCR) signalling is required to induce expression of the interleukin 2 (IL-2) gene in mouse T cells. Additional costimulation through CD28 augments IL-2 production by 30- to 100-fold. Using IL-2 RNA accumulation and transcription reporter assays, we have addressed potential mechanisms of CD28 regulation at various time points of stimulation. The kinetic regulation of IL-2 mRNA by TCR and CD28 signals is complex: (i) at the earliest detectable time point, CD28 signalling causes a 20-fold increase compared with TCR signalling alone; (ii) both groups rapidly accumulate mRNA for the first 4 h; (iii) IL-2 mRNA then disappears from cells stimulated through the TCR alone but plateaus or increases slightly in cells costimulated through CD28; and (iv) after 8 h, the mRNA disappears in cultures with the anti-CD28 antibody. Transcription reporter assays did not show a specific effect of CD28 signalling on IL-2 enhancer driven transcription. This was true for either a 353- or a 1.9-kb enhancer, over a broad range of kinetics and TCR occupancy, and with several TCR signal mimics. The early component of CD28 costimulation is nuclear, however, since the initial enhancement of mRNA is also found in unspliced IL-2 RNA. Between 2 and 6 h, there is a marked difference in the rates of decay of IL-2 mRNA in the presence and absence of the CD28 signalling. Rapid decay of IL-2 mRNA commences after 8 h even in the presence of CD28 signals, although the decay occurs at a rate slower than that seen after 4 h of anti-TCR stimulation alone. This complexity suggests the existence of two interesting molecular mechanisms by which CD28 costimulates lymphokine gene expression.
Animals↗
Streptococcus pneumoniae resistant to penicillin: incidence and potential therapeutic options.
Streptococcus pneumoniae was recovered from 12 (50%) samples of middle ear fluid of 24 consecutive patients with AOME and in mixed culture of middle ear pathogens from one (4%) additional specimen. Two (15.3%) isolates had intermediate resistance to penicillin (minimal inhibitory concentration (MIC) 0.125 and 1.0 micrograms/mL). The antimicrobial susceptibility to various antimicrobials of 30 S pneumoniae strains recovered from patients seen in the last 12 months was also determined. One of the patients with AOME developed bacteremia that resolved uneventfully, whereas the other developed meningitis. MIC90 was determined from penicillin (2 micrograms/mL), erythromycin (> 32 micrograms/mL), cefaclor (32 micrograms/mL), loracarbef (> or = 64 micrograms/mL), cefixime (16 micrograms/mL), ceftibuten (> 64 micrograms/mL), chloramphenicol (16 micrograms/mL), cefpodoxime (4 micrograms/mL), ciprofloxacin (2 micrograms/mL), cephalexin (> or = micrograms/mL), augmentin (2 micrograms/mL), cefprozil (8 micrograms/mL), clindamycin (64 micrograms/mL), TMP-SXT (> 64 micrograms/mL), clarithromycin (32 micrograms/mL), rifampin (0.06 micrograms/mL), cefuroxime (2 micrograms/mL), cefotaxime (0.25 micrograms/mL), vancomycin (0.25 micrograms/mL), and imipenem (0.5 micrograms/mL). Cefprozil, vancomycin, and rifampin inhibited all strains, whereas cefpodoxime, cefuroxime, clindamycin, and clarithromycin exhibited very good activity.
Anti-Bacterial Agents↗
Marijuana as medicine: making a silk purse out of a sow's ear.
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Cannabinoids↗
A recovery method for airborne gunshot residue retained in human nasal mucus.
Each living person is equipped with their own personal particle filter, a nose. The human nose is capable of filtering and trapping airborne gunshot residue (AGSR) from discharged firearms. An extraction/concentration technique has been developed to recover the AGSR retained in human nasal mucus. The technique has successfully recovered abundant AGSR from 48 hours postfiring sample collection times. The AGSR particles were characterized by a JEOL 6400 scanning electron microscope coupled with a Noran Voyager energy dispersive X-ray spectrometer.
Air Pollutants↗
A quantitative analysis of antigen-presenting cell function: activated B cells stimulate naive CD4 T cells but are inferior to dendritic cells in providing costimulation.
Ligation of CD28 on CD4 Th1 clones and freshly isolated mixtures of naive and memory CD4 T cells triggered their T cell receptors (TCR) is sufficient to induce the costimulatory signals necessary for interleukin 2 (IL-2) production by these cells. CTLA-4-reactive ligands expressed on antigen-presenting cells (APC) are critical in providing costimulatory signals to these T cell populations. We demonstrate that these activation characteristics apply equally to purified naive CD4 T cells. Because B cell blasts express CTLA-4-reactive ligands and high levels of adhesion and major histocompatibility complex class II molecules, they would be expected to engage both the TCR and CD28 and consequently stimulate IL-2 production by naive CD4 T cells. Using purified populations of cells in limiting dilution cultures, we have carried out a quantitative analysis of the interaction between naive CD4 T cells and either activated B or dendritic cells. We demonstrate that B cell blasts stimulate a high frequency of naive CD4 T cells. Slight differences in TCR signaling efficiency between the two APC types were observed. Even at optimal peptide concentrations, however, the amount of IL-2 made by individual T cells was fourfold lower in response to B cell blasts than to dendritic cells. This relative deficiency of activated B cells was due to their inability to optimally costimulate naive CD4 T cells.
Abatacept↗
Subset of CD4+ T cell clones expressing IL-3 receptor alpha-chains uses IL-3 as a cofactor in autocrine growth.
In this paper we demonstrate that IL-3 can act as a cofactor for the growth of some CD4+ T cells. This lymphokine synergized with IL-4 to induce both a unique set of protein tyrosine phosphorylations and the vigorous proliferation of the keyhole limpet hemocyanin-specific and I-Ab-restricted CD4+ Th0 cell clone, E6. In addition, neutralizing anti-IL-3 Abs specifically inhibited the growth of E6 T cells to Ag or anti-CD3 mAb stimulation. Finally, this T cell clone was shown to express both the IL-3R alpha-chain and an IL-3R beta-chain (AlC2A). An examination of other CD4+ T cell clones determined that one Th1 clone (A.E7), two Th0 clones (16B.2 and L9A.1), and one Th2 clone (D10.G4.1) were not influenced by the addition of rIL-3. However, proliferation of the Th2 clones CDC25 and CDC35 to CD3-stimulation was significantly enhanced by IL-3. The sensitivity of these latter two clones to IL-3 was also found to be associated with expression of IL-3R alpha-chains. Because E6 T cells are highly dependent on IL-4 for autocrine growth similar to Th2 cells, these results suggest that IL-3 may synergize with IL-4 to enhance the proliferation of a subset of IL-4-dependent CD4+ T cells, and the study indicates that IL-3R alpha-chain expression may be a specific marker of this CD4+ T cell subset.
Animals↗
A subset of CD4+ thymocytes selected by MHC class I molecules.
To complete their maturation, most immature thymocytes depend on the simultaneous engagement of their antigen receptor [alpha beta T cell receptor (TCR)] and their CD4 or CD8 coreceptors with major histocompatibility complex class II or I ligands, respectively. However, a normal subset of mature alpha beta TCR+ thymocytes did not follow these rules. These thymocytes expressed NK1.1 and a restricted set of alpha beta TCRs that are intrinsically class I-reactive because their positive selection was class I-dependent but CD8-independent. These cells were CD4+ and CD4-8- but never CD8+, because the presence of CD8 caused negative selection. Thus, neither CD4 nor CD8 contributes signals that direct their maturation into the CD4+ and CD4-8- lineages.
Animals↗
Marijuana as an antiemetic drug: how useful is it today? Opinions from clinical oncologists.
OBJECTIVE: To determine the antiemetic drug preferences of practicing adult oncologists and to estimate the frequency of use of marijuana smoke as an antiemetic agent. DESIGN: Identical mailed questionnaire surveys on antiemetic preferences, distributed prior to approval of ondansetron. SAMPLE: Two groups of practicing clinical adult oncologists were surveyed. The first group (N = 120) consisted of every twentieth board-certified, American member of the American Society of Clinic Oncology culled from the 1990 ASCO membership directory in alphabetical order. The second group (N = 60) consisted of every adult clinical oncologist in metropolitan Washington, D.C. MEASUREMENTS/RESULTS: Completed surveys were returned by 141 (78%) physicians; the responses from both groups were almost identical (Wilcoxon Rank Sum Test). Marijuana (either as marijuana smoke or oral tetrahydrocannabinol) ranked ninth in order of preference for the treatment of mild to moderate nausea and vomiting, and sixth for the treatment of more severe symptoms induced by chemotherapy. Most (94 or 65%) respondents reported having prescribed marijuana or oral THC 10 times or less; only 5 (3.5%) had prescribed such drugs more than 100 times which represented for them about 1% of their average lifetime clinical patient load. The respondents who had prescribed marijuana in any form thought that it had effectively relieved post-chemotherapy nausea or vomiting in 50% of patients. Unpleasant adverse effects were estimated to have occurred in 25% of treated patients. Only 8 (6%) respondents indicated that they would prescribe marijuana much more frequently--if there were no legal barriers associated with its medical use. CONCLUSION: Marijuana in any form was believed to be efficacious for 50% of patients with pre- or post-chemotherapy nausea or vomiting. However, one of four patients who received it complained of bothersome adverse effects. At the time of the study, cannabis was prescribed or recommended relatively infrequently by American clinical oncologists (i.e., those who actually prescribed chemotherapy). Even if it was freely available and restrictions on its use liberalized, smokeable marijuana, according to responses given on this survey, would not be used much more frequently by American oncologists.
Administration, Oral↗
Identification of the M1101K mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene and complete detection of cystic fibrosis mutations in the Hutterite population.
The Hutterite population is a genetic isolate with an increased incidence of cystic fibrosis (CF). Previously we identified three CF haplotypes defined by polymorphisms flanking the CF transmembrane conductance regulator (CFTR) gene. delta F508 was present on one of the haplotypes in only 35% of CF chromosomes. We hypothesized that the other two CF haplotypes, one of which was the most common and the other of which is rare, each harbored different non-delta F508 mutations. Single-strand conformation polymorphism analysis detected a missense mutation, M1101K, in both chromosomes of a Hutterite patient carrying the two non-delta F508 haplotypes. M1101K appears to have originated on an uncommon CFTR allele and to be infrequent outside the Hutterite population. The presence of M1101K on two haplotypes is likely the result of a CFTR intragenic recombination which occurred since the founding, 10-12 generations ago, of the Hutterite population. The crossover was located between exons 14a and 17b, an interval of approximately 15 kbp. delta F508 and M1101K accounted for all of the CF mutations in patients from 16 CF families representing the three subdivisions of the Hutterite population.
Adolescent↗
Costimulation of T lymphocytes: the role of CD28, CTLA-4, and B7/BB1 in interleukin-2 production and immunotherapy.
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Abatacept↗
Transactivation by AP-1 is a molecular target of T cell clonal anergy.
Anergy is a mechanism of T lymphocyte tolerance induced by antigen receptor stimulation in the absence of co-stimulation. Anergic T cells were shown to have a defect in antigen-induced transcription of the interleukin-2 gene. Analysis of the promoter indicated that the transcription factor AP-1 and its corresponding cis element were specifically down-regulated. Exposure of anergic T cells to interleukin-2 restored both antigen responsiveness and activity of the AP-1 element.
Animals↗
Induction of competence to respond to IL-4 by CD4+ T helper type 1 cells requires costimulation.
Rested murine CD4+ Th1 clones do not produce IL-4, but have previously been shown to be capable of responding to IL-4 if they are first activated with Ag and APC. In this study, we have examined the activation requirements for induction of competence to respond to IL-4 in these clones. TCR occupancy alone (given either as chemically fixed APC and Ag, anti-CD3, Con A, or ionomycin and PMA) was inadequate, but the addition of a source of costimulation to any of these stimuli resulted in complete induction of competence to respond to IL-4. Pretreatment of the Th1 clones with TCR occupancy alone induced an anergic state from which subsequent full stimulation with Ag and APC failed to give IL-4 responsiveness. Pretreatment of the cells with IL-2 alone was an inadequate signal to induce IL-4 responsiveness and only a partial response was obtained when TCR occupancy was combined with IL-2. Addition of anti-IL-2 and anti-IL-2R antibodies during full activation with APC and Ag gave a 50% inhibition of competence induction. These results demonstrate that costimulation, in addition to its role in IL-2 production, is an important second signal for inducing T cells to become competent to respond to IL-4.
Animals↗
Activation events during thymic selection.
During their differentiation in the mouse thymus, CD4+8- cells undergo several of the sequential changes observed upon normal activation of mature, peripheral CD4+ lymphocytes. Expression of CD69, an early activation marker, is first observed on a minority of cells at the T cell receptor (TCR)lo/med double-positive stage, is maximal (50-90%) on heat-stable antigen (HSA)hi TCRhi double-positive, HSAhi TCRmed CD4+8lo, and HSAhi TCRhi CD4+8- cells, and is downmodulated at the mature HSAlo CD4+8- stage. In contrast, CD44, a late activation marker, is selectively expressed at the HSAlo stage. The set of lymphokines that CD4+8- thymocytes can produce upon stimulation also characteristically expands from mainly interleukin 2 (IL-2) at the HSAhi stage, to IL-2 and very large amounts of IL-4, IL-5, IL-10, and interferon gamma (IFN-gamma) at the HSAlo stage. 1 in 30 HSAlo CD4+8- adult thymocytes secrete IL-4 upon stimulation through their TCR. This frequency is 25% of the frequency of IL-2 producers, about 100-fold above that of peripheral (mainly resting) CD4+ T cells. With time after their generation in organ culture, CD4+8- thymocytes lose their capacity to secrete IL-4, IL-5, and IFN-gamma, but not IL-2. Similarly, the frequency of IL-4, but not of IL-2, producers progressively decreases after emigration to the periphery as judged by direct comparison between thymic and splenic CD4+ cells in newborns, or by following the fate of intrathymically labeled CD4+8- cells in adults after their migration to the spleen. This sequence suggests that thymic selection results from an activation process rather than a simple rescue from death at the double-positive stage, and shows that the functional changes induced after intrathymic activation, although transient, are still evident after export to the periphery.
Animals↗
Reversal of in vitro T cell clonal anergy by IL-2 stimulation.
Stimulation of a normal type I mouse T helper cell clone (TH1) with concanavalin A in the absence of antigen presenting cells (APC) in vitro results in the induction of a hyporesponsive state known as T cell clonal anergy. This state is characterized by a decrease in proliferation following stimulation with antigen and APC resulting from a decrease in the production of IL-2. Production of the lymphokines IL-3/granulocyte macrophage colony stimulating factor and IFN-gamma is also reduced, although to a lesser degree. Stimulation of such anergic cells with IL-2 results in proliferation and a complete reversal of the state. We demonstrate that this reversal is not due to the outgrowth of a subpopulation of cells that had escaped anergy induction, but rather occurs in all the cells. Anergy also dissipated spontaneously, although much more slowly, in the absence of T cell antigen receptor occupancy. Finally, we show that a similar state can be produced by normal activation with antigen and APC if IL-2 and other factors are removed at 16-20 h. These results indicate that the anergic state is not a permanent change in the TH1 cell. Anergy induction appears to be a consequence of the inability of the cell to divide extensively following stimulation through the antigen-specific receptor. We propose a model to explain these results in terms of a relatively stable negative regulatory factor.
Animals↗
Decision-making autonomy in nursing.
Current nursing literature has suggested that nurses may have low needs or preferences for decision-making autonomy. In this study, the authors found that nurses differed in their preferences for decision-making autonomy in three types of work-related decisions. Employed nurses with a greater preference for autonomy were more satisfied with their jobs, and those with little or no such preference were less satisfied, as they gained decision-making influence over patient care and unit management. The authors discuss implications for designing and implementing decision-making programs.
Adult↗