Cytochalasin B: Effects upon Microfilaments Involved in Morphogenesis of Estrogen-Induced Glands of Oviduct

The administration of estrogen to immature chicks induces formation of tubular glands and differentiation of cells in the oviduct. As glands begin to form, organized bundles of 40-50 A filaments appear at the luminal end of the cells. These structures are not present in uninduced oviducts. Cytochalasin treatment of oviducts early in gland formation results in the disappearance of young glands already present and the inhibition of new gland formation. Furthermore, organized microfilaments are no longer present. When the oviducts are washed free of cytochalasin, however, organized bundles of microfilaments reappear.The correlations between the presence of filaments and formation and glands suggest that filaments are important agents in morphogenesis, presumably because of contractile properties which generate changes in cell shape and, consequently, tissue shape.     

Cycloheximide impairs and enhances memory depending on dose and footshock intensity

This experiment examined the effects on memory of interactions of cycloheximide dose and training foot shock intensity. Mice received injections of cycloheximide (120 mg/kg, s.c.) or saline 30 min prior to inhibitory avoidance training with shock intensities of 100, 150, 250 or 300 μA (1 s duration). Memory was tested 48 h later. The saline control mice showed increasing memory latencies as a function of shock intensity. The ability of cycloheximide to impair memory increased as the training shock intensity increased. In a second experiment, mice were trained with a 200 μA (1 s duration) shock and received injections of saline or cycloheximide at one of several doses (30, 60 or 120 mg/kg). Under these training conditions, cycloheximide enhanced memory in an inverted-U dose-response manner. These findings are consistent with prior findings suggesting that protein synthesis inhibitors act on memory by altering modulators of memory formation as a secondary consequence of the inhibition of protein synthesis rather than by interfering with training-initiated synthesis of proteins required for memory formation.     

Assembly of contact-phase factors on the surface of the human neutrophil membrane

H-kininogen (HK), a major factor involved in contact-phase activation, was recently immunolocalized on the external surface of human neutrophils. Experiments were, therefore, designed to consider the question of whether the complete assembly of contact factors occurs on the outer surface of the neutrophil membrane. By immunolocalization techniques, and using specific antibodies directed against the various contact factors, we now demonstrate that plasma prekallikrein (PK), factor XI (FXI), and factor XII (FXII) are present on the exterior face of the human neutrophil. Failure to localize HK, PK, or FXI by monoclonal antibodies directed to their reciprocal binding sites, and displacement of PK/FXI by peptide HK31, which mimics the relevant binding site(s) of HK, suggested that prekallikrein and FXI are anchored to the neutrophil membrane through attachment to the kininogen molecule. Probing of the kinin moiety by a specific antibody showed that kininogen molecules bound to the neutrophil cell membrane contain the kinin sequence, which can be released by plasma kallikrein or by tissue kallikrein. Our results led us to the novel conclusion that neutrophils provide a circulating platform for the components of the contact-phase system.     

Regression of experimental Burkitt's lymphoma induced by Epstein-Barr virus-immortalized human B cells

Epstein-Barr virus (EBV)-immortalized human B cells survive only transiently when injected subcutaneously into athymic mice, whereas Burkitt's lymphoma cells give rise to progressively growing subcutaneous tumors. In this study, we tested whether these Burkitt's tumors could be induced to regress via a bystander effect induced by EBV-immortalized B cells. Simultaneous inoculation of EBV-immortalized B cells and Burkitt's lymphoma cells in the same subcutaneous site resulted in tumors that regressed with necrosis and scarring. Similarly, simultaneous inoculation of EBV-immortalized B cells and Burkitt's lymphoma cells in separate subcutaneous sites resulted in regression of a proportion of the Burkitt's tumors. Furthermore, most of the established human Burkitt's tumors regressed with necrosis and scarring after intratumor inoculations with EBV-immortalized B cells. The EBV-immortalized B cells continued to exert this antitumor effect even when killed with irradiation. The experimental approach to Burkitt's lymphoma treatment described here exploits the ability of athymic mice to reject EBV-immortalized B cells to target an effective antitumor response to malignant cells normally incapable of eliciting it.     

Feedback to emergency medical services providers: the good, the bad, and the ignored

HYPOTHESIS: To determine the type and frequency of immediate unsolicited feedback received by emergency medical service (EMS) providers from patients or their family members and emergency department (ED) personnel. METHODS: Prospective, observational study of 69 emergency medical services providers in an urban emergency medical service system and 12 metropolitan emergency departments. Feedback was rated by two medical student observers using a prospectively devised original scale. RESULTS: In 295 encounters with patients or family, feedback was rated as follows: 1) none in 224 (76%); 2) positive in 51 (17%); 3) negative in 19 (6%); and 4) mixed in one (< 1%). Feedback from 254 encounters with emergency department personnel was rated as: 1) none in 185 (73%); 2) positive in 46 (18%); 3) negative in 21 (8%); and 4) mixed in 2 (1%). Patients who had consumed alcohol were more likely to give negative feedback than were patients who had not consumed alcohol. Feedback from emergency department personnel occurred more often when the emergency medical service provider considered the patient to be critically ill. CONCLUSIONS: The two groups provided feedback to emergency medical service providers in approximately one quarter of the calls. When feedback was provided, it was positive more than twice as often as it was negative. Emergency physicians should give regular and constructive feedback to emergency medical services providers more often than currently is the case.     

Aminophylline therapy for acute bronchospastic disease in the emergency room

OBJECTIVE: To assess the role of aminophylline in the treatment of acute exacerbations of bronchospastic disease when used in addition to inhaled beta-agonists and intravenous corticosteroids. DESIGN: Randomized, double-blind, placebo-controlled intervention study. PATIENTS: One hundred thirty-three adult patients with either asthma or chronic obstructive pulmonary disease who presented to the emergency department with asthma or wheezing. INTERVENTIONS: All patients received therapy with both aerosolized metaproterenol and intravenous methyl-prednisolone. Patients were randomly assigned to receive either a loading dose of aminophylline followed by a routine infusion (n = 65) or an equal volume of placebo as a loading dose and infusion (n = 68). MEASUREMENTS AND MAIN RESULTS: At discharge from the emergency department, the median serum theophylline concentration for the aminophylline group was 54 mumol/L (9.7 mg/L). The two groups showed no differences (P greater than 0.2) in measurements of forced expiratory volume at 1 second (FEV1), forced vital capacity (FVC), or peak expiratory flow rate (PEFR) at baseline or at 60 or 120 minutes after aminophylline administration. Neither patient satisfaction nor physician assessment of response to therapy differed between the two groups. There was no difference (P greater than 0.2) in the frequency of side effects, except for a trend toward a higher frequency of nausea (P = 0.13) in the aminophylline group. There was, however, a threefold decrease in the hospital admission rate for patients treated with aminophylline (6%) compared with placebo recipients (21%) (P = 0.016). CONCLUSION: Aminophylline, in doses producing levels just below the commonly accepted therapeutic range, appears to decrease hospital admissions in patients with acute exacerbation of asthma or chronic obstructive pulmonary disease. This finding, if confirmed in larger studies, may represent a substantial cost savings.     

Natural killer cell precursors in the CD44neg/dim T-cell receptor population of mouse bone marrow

Natural killer (NK) cells develop from the nonadherent cell component of NK long-term bone marrow (BM) cultures (NK-LTBMC). Because these nonadherent cells are depleted of mature NK cells and T cells, but appear to enriched for NK precursors, they were used as a starting population to begin to define the NK precursors that function in NK- LTBMC. As the stromal cell component of NK-LTBMC has been shown to support interleukin (IL)-2-induced, CD44 dependent, NK cell development from nonadherent NK precursors, NK-LTBMC stroma was used in a limiting dilution assay (LDA) to quantitate the precursors. NK-LTBMC in 96-well plates were irradiated (20 Gy) to kill hematopoietic cells (including the NK precursors), seeded with limiting dilutions of the cells to be quantitated, cultured with 500 U/mL IL-2 for 13 days and assayed for development of NK activity by adding 51Cr-labeled YAC-1 cells to the wells and evaluating the release of 51Cr after 4 hours. Flow cytometric analysis, sorting, and quantitation of the nonadherent cell component of NK-LTBMC showed that NK precursors were concentrated in the CD44neg/dim subset that comprised 10% of the "lymphoid" gated cells. When the CD44neg/dim subset was sorted from BM of mice treated with 5- fluorouracil (5-FU) day before (-1FUBM), there were about 30% T cells, but no NK-1.1+ cells. When the T cells were removed by sorting and the CD44neg/dim, alphabeta, gammadelta T-cell receptorneg (TCR-) subpopulation was seeded onto irradiated stroma with IL-2, they proliferated, developed NK activity, became NK-1.1+ and CD44bright and remained alphabeta, gammadelta TCR-. The frequency of NK precursors in this population as estimated from the LDA was about 1/500.     

An Electronic Health Record Based on Structured Narrative

Objective

To develop an electronic health record that facilitates rapid capture of detailed narrative observations from clinicians, with partial structuring of narrative information for integration and reuse.

Design

We propose a design in which unstructured text and coded data are fused into a single model called structured narrative. Each major clinical event (e.g., encounter or procedure) is represented as a document that is marked up to identify gross structure (sections, fields, paragraphs, lists) as well as fine structure within sentences (concepts, modifiers, relationships). Marked up items are associated with standardized codes that enable linkage to other events, as well as efficient reuse of information, which can speed up data entry by clinicians. Natural language processing is used to identify fine structure, which can reduce the need for form-based entry.

Validation

The model is validated through an example of use by a clinician, with discussion of relevant aspects of the user interface, data structures and processing rules.

Discussion

The proposed model represents all patient information as documents with standardized gross structure (templates). Clinicians enter their data as free text, which is coded by natural language processing in real time making it immediately usable for other computation, such as alerts or critiques. In addition, the narrative data annotates and augments structured data with temporal relations, severity and degree modifiers, causal connections, clinical explanations and rationale.

Conclusion

Structured narrative has potential to facilitate capture of data directly from clinicians by allowing freedom of expression, giving immediate feedback, supporting reuse of clinical information and structuring data for subsequent processing, such as quality assurance and clinical research.