Area security unit in a psychiatric hospital.

Since 1974 a psychiatric hospital security unit, designed to serve the whole catchment area, has cared for mentally ill (mostly psychotic) patients with disturbed behaviour that cannot be managed in open wards. There are a few long-term dangerous patients but most stay only briefly. The admission of women to the unit was not followed by the expected reduction in violence. The unit has facilities for occupational therapy, physical recreation, work, and study, which are particularly important for those who are too dangerous to leave it. The unit''s calming influence depends as much on the supportive effect of the high staff ratio as on the use of tranquillisers. This type of unit is not suitable for patients with personality disturbances who "act out" or for mentally abnormal offenders; but it functions well as a crisis centre for the disturbed mentally ill, and there is an increasing demand for its services.     

Schistosoma incognitum from Cikurai,West Java,Indonesia

Schistosoma incognitum is reported for the first time from West Java, Indonesia where 84% of ricefield rats, Rattus argentiventer, were infected. Radix auricularia rubiginosa snails were intermediate hosts. The adult stage of the Javanese strain of S. incognitum and lesions in naturally-infected rodents are described. Rattus exulans, Rattus norvegicus and Mus musculus were experimentally infected. Epizootiology is similar to that described in other countries.     

Cell surface action of thrombin is sufficient to initiate division of chick cells

Thrombin covalently linked to carboxylate-modified polystyrene beads initiated division of quiescent chick embryo (CE) cells either in medium containing low levels of serum or in serum-free medium. Release of thrombin was monitored by measuring acid-precipitable radioactivity released from 125I-thrombin beads into the medium during incubation with cells. Even if all of the acid-precipitable material released from the beads were active thrombin, it was not sufficient to account for any of the observed cell division, and was 10-30 fold less than the amount necessary to produce the increase in cell number caused by the thrombin beads. Two other kinds of experiments also showed that material released into the medium did not account for the observed initiation of cell division. First, medium taken from cultures incubated with thrombin beads did not initiate cell division when added to new quiescent cultures. Second, in coverslip experiments where populations of cells with an without thrombin feads shared the same medium, only bead-contacted cells divided. Several results suggested that the material which was released from the thrombin beads resulted from cell-associated proteolysis rather than from "leakage" of intact thrombin from the beads. For example, after incubating 125I-thrombin beads with or without CE cells, we were unable to detect any intact thrombin released into the medium. In addition, most of the material released from the beads was acid-soluble and was only released in the presence of CE cells. A few thrombin beads were endocytosed by CE cells, but they were surrounded by an intact plasma membrane. Thus they did not directly interact with the cytoplasm. The close association of many of the beads with the cell surface and the presence of a few beads in endocytic vesicles made it important to consider the possibility that thrombin might be released from the beads directly into the cells. This possibility was explored using ultrastructural (EM) autoradiography. With this technique (where one grain represented 700--900 thrombin molecules), we found that beads inside the cells had approximately the same number of grains as beads not in contact with cells. This suggested that little, if any, additional radioactive material had been released from the beads which were in contact with the cells. In addition, we were unable to detect any grains in the cytoplasm which could be attributed to released thrombin, even using an amount of 125I-thrombin beads which was 8 fold greater than the amount which produced maximal cell division. Taken together, these results provide direct evidence that thrombin action at the cell surface is sufficient to initiate division of CE cells.     

Increasing carbon dioxide from five percent to ten percent improves rabbit blastocyst development from cultured zygotes.

One-cell rabbit zygotes were cultured at 39 degrees C in basal synthetic medium II (BSM-II) with 5%, 10%, or 15% CO2 and humidified air to determine the effect of CO2 concentration on development in vitro. After 4 days in culture, 37% of the embryos grown in 10% or 15% CO2 had reached the hatching blastocyst stage, but only 10% of the embryos were hatching when cultured under 5% CO2 (P = 0.01). Over all blastocysts, cell numbers were 207, 246, and 205 for the 5%, 10%, and 15% CO2 treatments, respectively. In a second experiment to determine if there was a beneficial effect, particularly at the blastocyst stage, of a higher concentration of CO2, embryos were cultured 4 days in either 5% or 10% CO2 or for 2 days in 5% CO2 followed by 2 days in 10% CO2. The numbers of blastomeres per embryo and embryo diameter were greater (P < 0.05) in embryos cultured continuously in 10% CO2 or in 10% CO2 only during days 3 and 4 of culture than in embryos cultured continuously in 5% CO2. In a third experiment, one-cell rabbit zygotes were cultured with 5% or 10% CO2 in a defined, protein-free medium consisting of 1:1 RPMI 1640 and Dulbecco's modified Eagle's medium. The proportion of embryos hatching and cell counts were significantly greater (P < 0.01) when cultured in the presence of 10% CO2. These data indicate that a 10% CO2 atmosphere exerts a beneficial effect on the development of zygotes into expanding and hatching rabbit blastocysts in vitro.     

The extracellular domain of p185/neu is released from the surface of human breast carcinoma cells, SK-BR-3.

The human breast carcinoma cell line SK-BR-3, expresses the neu oncogene product, p185, which is a receptor tyrosine kinase. Using a double monoclonal antibody capture enzyme-linked immunosorbent assay for p185, activity was detected in conditioned media from cultures of SK-BR-3 cells. Two monoclonal antibodies specific for the extracellular domain of p185/neu immunoprecipitated a protein with a molecular mass of approximately 105 kDa. p105 was further shown to compete with p185 for binding to monoclonal antibodies and pulse-chase experiments indicate that it was generated by post-translational processing. Peptide maps showed that p105 and p185 are related polypeptides. Since p105 is close to the predicted size for the extracellular domain of p185/neu, we propose that SK-BR-3 cells specifically process and release this portion of the receptor into the medium. The release of the extracellular domain may have implications in oncogenesis and its detection could prove useful as a cancer diagnostic.     

Estrogen modulates Ca(2+)-independent lipid-stimulated kinase in the rabbit corpus luteum of pseudopregnancy. Identification of luteal estrogen-modulated lipid-stimulated kinase as protein kinase C delta.

Rabbit corpora lutea were tested for the presence of phosphorylative responses sensitive to estrogen. Luteal Ca(2+)-independent lipid-stimulated kinase activity was detected by phosphorylation of the endogenous substrate, p76. Estrogen treatment, by way of estradiol-17 beta implant, increased levels of the lipid-stimulated phosphoprotein 2-3-fold throughout pseudopregnancy. Midpseudopregnant rabbit luteal extracts were further evaluated to determine the identity of the lipid-stimulated kinase. Results of low pH-activated phosphorylation were consistent with the identification of p76 as an autophosphorylated member of the protein kinase C (PKC) family. Partial purification of the luteal lipid-stimulated kinase was performed using sequential DEAE-cellulose/hydroxylapatite chromatographies and using gel filtration. Western immunoblot with type-specific anti-PKC delta antiserum showed coelution of kinase p76 activity with immunoreactive PKC delta. Immunoblot analysis confirmed that luteal levels of PKC delta were increased by estrogen treatment.     

Ovulation and embryo recovery rates following immunization of mares against an inhibin alpha-subunit fragment

Six normally cycling mares were immunized 5 times at 3-week intervals with a synthetic porcine inhibin alpha-subunit fragment which had been conjugated to bovine serum albumin and emulsified in Freund's incomplete adjuvant. Immunized mares ovulated a significantly larger (P < 0.01) number of follicles per estrous cycle (2.8 +/- 1.1; range 1 to 8 ovulations) than 14 nonimmunized control mares (1.1 +/- 0.1; range 1 to 2 ovulations). Day-7 embryo recovery rates tended to be higher (P < 0.1) in immunized mares (1.6 +/- 0.5 embryos per flush) than in control mares (0.7 +/- 0.2 embryos per flush). No differences in interovulatory intervals were found between the 2 groups. These results indicate that immunization against inhibin may be useful in inducing development and ovulation of multiple follicles for embryo transfer in the mare.     

The zooplankton-phytoplankton interface in lakes of contrasting trophic status: an experimental comparison

We report here the results of an experimental study designed to compare algal responses to short-term manipulations of zooplankton in three California lakes which encompass a broad range of productivity (ultra-oligotrophic Lake Tahoe, mesotrophic Castle Lake, and strongly eutrophic Clear Lake). To assess the potential strength of grazing in each lake, we evaluated algal responses to a 16-fold range of zooplankton biomass. To better compare algal responses among lakes, we determined algal responses to grazing by a common grazer (Daphnia sp.) over a range ofDaphnia densities from 1 to 16 animals per liter. Effects of both ambient grazers andDaphnia were strong in Castle Lake. However, neither ambient zooplankton norDaphnia had much impact on phytoplankton in Clear Lake. In Lake Tahoe, no grazing impacts could be demonstrated for the ambient zooplankton butDaphnia grazing had dramatic effects. These results indicate weak coupling between phytoplankton and zooplankton in Clear Lake and Lake Tahoe, two lakes which lie near opposite extremes of lake trophic status for most lakes. These observations, along with work reported by other researchers, suggest that linkages between zooplankton and phytoplankton may be weak in lakes with either extremely low or high productivity. Biomanipulation approaches to recover hypereutrophic lakes which aim only to alter zooplankton size structure may be less effective if algal communities are dominated by large, inedible phytoplankton taxa.     

Receptor-bound thrombin is not internalized through coated pits in mouse embryo cells

The localization of thrombin receptors on mouse embryo (ME) cells was examined using electron microscope (EM) immunocytological techniques. ME cells were fixed with formaldehyde, prior to thrombin binding, and thrombin visualized on cell surfaces using affinity-purified antithrombin rabbit antibody and colloidal gold labeled anti-rabbit IgG. Colloidal gold particles were found in clusters on the surface of cells incubated with thrombin. There were approximately seven particles per cluster observed in thin sections with cluster diameters ranging from 70 to 200 nm. These clusters were not observed on cells incubated without thrombin. The total number of particles present on cells incubated with and without thrombin indicate that the colloidal gold labeling is approximately 98% specific for thrombin. Only four colloidal gold particles out of approximately 1,200 were associated with coated pits. Thus the thrombin receptor clusters do not appear to associate with coated membrane regions. To determine whether receptor-bound thrombin was internalized by receptor-mediated endocytosis, ME cells were incubated with 125I-thrombin and examined using EM autoradiography and the trypsin sensitivity of 125I-thrombin which was associated with the cells. In two types of experiments, where thrombin was incubated with cells at 4 degrees C and the temperature increased to 37 degrees C and where initial incubation was at 37 degrees C, the receptor-directed specific internalization proceeded at approximately the same rate as nonspecific internalization. These studies indicate that thrombin that binds to its receptors on ME cells is not rapidly internalized by receptor-mediated endocytosis.     

Visualization of thrombin receptors on mouse embryo fibroblasts using fluorescein-amine conjugated human α-thrombin

The localization of thrombin receptors on mouse embryo (ME) cells has been examined by direct fluorescence microscopy using a fluorescein aminelabeled thrombin. Two fluorescein amines, 4-(N-6-aminoethyl thioureal)-fluorescein and 4-(N-6-aminohexyl thioureal)-fluorescein, were synthesized and attached to the carbohydrate moiety of highly purified human α-thrombin by periodate oxidation of the carbohydrate and selective reduction of the Schiff's base using sodium cyanoborohydride. Preparations of fluorescent thrombin with from 1 to 4 fluoresceins per molecule of thrombin retained their ability to proteolytically cleave fibrinogin to form fibrin clots, to bind to thrombin receptors on ME cells, and to initiate cell division. After incubating mitogenic concentrations of the fluorescein amine labeled thrombin with ME cells at 4°C, a diffuse fluorescent pattern was observed over the surface of the ME cells. This diffuse pattern was specific: it was not observed on cells from parallel cultures incubated with fluorescent thrombin plus a 20-fold excess of unlabeled thrombin. Thus, thrombin receptors appear to be distributed randomly over the surface of ME cells prior to interaction with thrombin. Increasing the temperature to 37°C following binding at 4° C resulted in a rapid dissociation of the fluorescent pattern from the cells leaving only the autofluorescent vesicles. This result may reflect the unique ability of thrombin to proteolytically cleave its own receptor.