Use of a synthetic peptide-based elisa for the diagnosis of infectious mononucleosis and other diseases

A simple enzyme immunoassay has been developed based on measuring antibodies to synthetic peptides corresponding to sequences in the Epstein-Barr nuclear antigen (EBNA). This assay, which is reproducible, quantitative, and simple to perform and interpret, can be an effective tool to aid in the diagnosis of infectious mononucleosis and nasopharyngeal carcinoma.     

Collaborative Practice Through Nursing Case Management

A 528-bed community teaching hospital redesigned its patient care delivery system, implementing a collaborative practice model on the 30-bed inpatient rehabilitation unit in April 1990. This model is a patient-centered delivery model that encourages the healthcare team to facilitate the achievement of patient outcomes within effective time frames and with an appropriate use of resources. The collaborative practice model includes a nurse case manager's role for the staff nurse, which had as its framework the concept of nursing case management. Tested project management techniques were used to ensure a successful implementation process. Various strategies, such as using project teams and providing educational programs, were used to respond to the issues of role conflict and overlap, especially between social workers and nurse case managers. The implementation of this model provided a number of benefits, including improved interdisciplinary relationships and decreased length of stay.     

Development of a flow cytometry based method for rapid and sensitive detection of a novel marine fish iridovirus in cell culture

A sensitive and accurate flow cytometry (FCM) based method has been developed to detect and quantitate a novel marine fish iridovirus (Singapore grouper iridovirus, SGIV) after amplification in cell cultures. Confluent grouper cell (GP) monolayers were infected with SGIV. When advanced cytopathic effect (CPE) appeared, the cell cultures were fixed and permeabilized, and then reacted with monoclonal antibodies specific against SGIV, followed by a second antibody conjugated with FITC (anti-mouse IgG-FITC). A Coulter EPICS Elite ESP flow cytometer was used to directly detect and analyze the percentage of virus-infected cells. Three fixation and permeabilization methods were evaluated. The kinetics of the virus infection process was determined. The FCM procedure enables large amounts of cells to be screened rapidly for infectivity, and it can also detect low levels of virus infection. As early as 8 h after inoculation with the virus, 0.34% of infected cells were detected in cell culture. The maximum level of infection was obtained at 72 h. The efficiency and reliability of the FCM procedure were compared with those of the standard methods of immunofluorescence microscopy and PCR.     

Activation-induced polarized recycling targets T cell antigen receptors to the immunological synapse; involvement of SNARE complexes

The mechanism by which T cell antigen receptors (TCR) accumulate at the immunological synapse has not been fully elucidated. Since TCRs are continuously internalized and recycled back to the cell surface, we investigated the role of polarized recycling in TCR targeting to the immunological synapse. We show here that the recycling endosomal compartment of T cells encountering activatory antigen-presenting cells (APCs) polarizes towards the T cell-APC contact site. Moreover, TCRs in transit through recycling endosomes are targeted to the immunological synapse. Inhibition of T cell polarity, constitutive TCR endocytosis, or recycling reduces TCR accumulation at the immunological synapse. Conversely, increasing the amount of TCRs in recycling endosomes before synapse formation enhanced their accumulation. Finally, we show that exocytic t-SNAREs from T cells cluster at the APC contact site and that tetanus toxin inhibits TCR accumulation at the immunological synapse, indicating that vesicle fusion mediated by SNARE complexes is involved in TCR targeting to the immunological synapse.     

Leptin effects on food and water intake in lines of chickens selected for high or low body weight

There is an association between autonomic nervous system output and obesity. The sympathetic nervous system stimulates lipid metabolism and regulates food intake and, hence, body weight. Leptin, produced by adipocytes in proportion to their size, has been shown to directly stimulate the satiety center. In the experiment reported here, food and water intake were compared after intracerebroventricular administration of human recombinant leptin to lines of chickens that had undergone divergent selection for over 45 generations from a common White Rock base population for high (HWS) or low (LWS) body weight at 8 weeks-of-age. Leptin caused a linear decrease in food intake in chickens from the LWS line whereas no effect was observed in those from the HWS line. The HWS chickens tended to have reduced water intake post leptin administration. Others reported that leptin decreased food intake in both broiler and Leghorn chickens. Leptin concentration in the central nervous system may not contribute directly to the difference of body weight between HWS and LWS chickens.     

Thyroid-stimulating antibody (TSAb) detected in sera of Graves'' patients using human thyroid cell cultures

As a homologous system is required to evaluate the effect of thyroid-stimulating antibody (TSAb) present in the serum of Graves' patients, primary cultures obtained from normal human thyroid gland have been used and the stimulatory effect measured as an increase of cAMP intracellular levels.

Monolayer cell cultures were stimulated by IgG purified from sera of Graves' patients or control subjects and compared to the effect of bovine TSH. Bovine TSH produced a dose-dependent increase in cAMP intracellular levels between 0·05 mU and 2·5 mU/ml, reaching a maximal value after 30 min with higher doses. While normal IgG had no effect, IgG prepared from untreated patients with frank Graves' disease elicited a significant increase in cAMP accumulation at a concentration between 0·05 and 0·5 mg/ml within 60 min in thirteen out of fourteen patients. A longer incubation period showed no further increase in cAMP values, even if in one case a higher concentration (5·0 mg/ml) of Graves' IgG had a delayed response. When the cAMP intracellular level modifications produced by Graves' IgG preparations in thyroid cell cultures were compared to those evoked in thyroid slices, an identical percentage (93%) of positive cases was obtained, without a coincidence of negative cases. Using thyroid slices the cAMP intracellular increase above basal levels was higher, if considered as a percentage, but in cultured cells a very low IgG concentration was sufficient to detect the presence of TSAb. No correlation between the two assays was found.

In conclusion, normal human cultured thyroid cells appeared to be a more suitable substrate when compared to human thyroid slices for detecting the presence of TSAb in Graves' disease and for studying its effect on thyroid cells. However, a 100% TSAb positivity was present in our Graves' patient series only when both assays were used.

     

Oculoauriculovertebral anomaly: Segregation analysis

Seventy-four families of probands with oculoauriculovertebral anomaly were evaluated, including 116 parents and 195 off-spring. Relatives were examined to identify ear malformations, mandibular anomalies, and other craniofacial abnormalities. For segregation analysis using POINTER, selection of the sample was consistent with single as-certainment. Different population liabilities were used for probands and relatives, because affection was narrowly defined for probands and broadly defined for relatives. The hypothesis of no genetic transmission was rejected. The evidence favored autosomal dominant inheritance; recessive and polygenic models were not distinguishable. © 1992 Wiley-Liss, Inc.     

Intracellular ion activities and Cl-transport mechanisms in bullfrog corneal epithelium

Cell membrane potentials, cell membrane resistances, and intracellular ionic activities were measured in bullfrog corneal epithelium. Equivalent circuit analysis was performed by adding adenosine to the apical surface and assuming that only the apical membrane is initially affected. From single-ion substitutions in the apical bathing solution, the apical membrane was found to have a high Cl- permeability, a low K+ permeability, and an unmeasurably small Na+ permeability. Under control conditions intracellular Cl- activity (aCli) was 22 +/- 2 (SE) mM, intracellular Na+ activity (aNai) was 14 +/- 3 mM, and intracellular K+ activity (aKi) was 106 +/- 5 mM. The electrical potential differences across apical and basolateral membranes were about 50 and 67 mV, respectively, both cell negative. aCli and aKi are higher, whereas aNai is much lower than predicted for equilibrium distribution. Inasmuch as Cl- is transported from the basolateral (stromal) to the apical (tear) side, basolateral entry of this anion is uphill and apical exit is downhill. Basolateral entry is Na+ dependent, as evidenced by a fall of aCli to near-equilibrium values after basolateral Na+ removal. The electrochemical gradient for Cl- efflux across the apical membrane is large enough to account for Cl- transport by electrodiffusion only. Na+ removal from the basolateral solution causes a reversible decrease of apical membrane Cl- permeability. The results support the hypothesis that net transepithelial Cl- transport results from coupled NaCl entry (or an equivalent process) at the basolateral membrane and electrodiffusional Cl- exit at the apical membrane.