Changes of immunoreactive somatostatin and beta-endorphin content in rat brain after amygdaloid kindling

A possible contribution of brain beta-endorphin and somatostatin to the epileptogenicity established by amygdaloid kindling was investigated in rats. Fourteen male rats were chronically implanted with electrodes placed bilaterally into the amygdala. The rats received 1 sec of electrical stimulation to the left amygdala each day. Generalized seizures were observed on average 10 days after initiation of kindling and the electrical stimulation was continued up to twenty-one days. Two months after the completion of the kindling procedure, each kindled and control rat was killed by microwave irradiation and the brains were dissected on ice into thirteen subregions. Each region was homogenized and centrifuged twice in 0.1 N acetic acid. The supernatant extracts were decanted and stored at - 20 degrees C until assay. Immunoreactive beta-endorphin and somatostatin were measured by radioimmunoassays. There were no significant differences in brain beta-endorphin contents between the two groups. In kindled rats, immunoreactive somatostatin was increased significantly in amygdala, sensorimotor, piriform, and entorhinal cortex. The results suggest that changes in somatostatin may be associated with epileptic susceptibility induced by the electrical kindling procedure.     

Development of nurse cell-oocyte interactions in the insect telotrophic ovary (Rhodnius prolixus)

The establishment and reorganization of intercellular bridges during larval-adult ovarian differentiation is the basis of the syncytial nature of the adult hemipteran telotrophic ovary. The formation, in the late differentiation phase, of groups of closely arranged nurse cell nuclei occupying a common cytoplasm results from membrane fusions. Oocyte-oocyte intercellular bridge systems later are modified to form the trophic cords. The trophic core, which undergoes a restructuring during the late differentiation phase, mediates nurse cell-oocyte interactions in this system. Material, transported to and accumulated by late differentiation phase pre-vitellogenic oocytes, originates from trophic core restructuring and zone III nurse cell production.     

Immunoregulatory factors from a human macrophage-like cell line. II. A human T-cell lymphokine-induced suppressor factor for lymphocyte proliferation

It has been demonstrated that the human histiocytic lymphoma-derived cell line U937, which has monocytoid characteristics, responds to a concanavalin A-induced T-cell-derived suppressor supernatant (T-SFS) with the release of a factor markedly suppressing mitogen-stimulated proliferation of normal peripheral blood lymphocytes. The suppressor material is not dialyzable, appears within 2 hr of exposure of U937 cells to the T-SFS, persists for at least 24 hr, and has a Mr of approximately 40,000 by gel chromatography. The suppressor factor does not affect the proliferation of continuous T- and B-lymphoid cell lines, distinguishing it from the inhibitor of DNA synthesis also released by U937, but appears to be specific for a stage of activation of normal lymphocytes that is independent of (a) utilization of interleukin-2 and (b) inhibition of production of interleukin-2.     

Littoral mollusc communities and water quality in southern Lake Winnipeg, Manitoba, Canada

Water quality and mollusc communities have been declining in Lake Winnipeg., the tenth largest freshwater lake in the world. Ninety sites were surveyed in the southern half of the lake. Nitrate and total dissolved solids were found to be significantly higher on the west side, while cadmium, copper and lead were higher on the east side. Agriculture, urban effluent, and recreational development were major factors directly affecting nearshore water quality. Human impacts were sporadically aggravated by Red River floodwaters entering the lake. A total of 26 gastropod were currently found in the lake, but 16 of them were found at 5 or fewer sites. Only 6 unionid species were found, compared to at least 11 historical species records. Species richness of both gastropods and unionids was positively correlated with total dissolved solids, and inversely with lead. Gastropod and unionid species richness were also mutually positively correlated. Catchment basin and shoreline management policies affecting Lake Winnipeg need to be reexamined to reduce further habitat decline.     

Human monocyte chemiluminescence triggered by IgG aggregates. Requirement of phospholipase activation and modulation by Fc receptor ligands

Human mononuclear cells stimulated with soluble IgG aggregates generated chemiluminescence, a response attributable to monocytes. Some requirements of this reaction were examined by preincubation of the cells with a variety of inhibitors. The protease antagonists TPCK and TLCK, the phospholipase inhibitors quinacrine and BPB, and the calcium channel blocker verapamil were all inhibitory at micromolar concentrations. The oxygen metabolite scavengers SOD and catalase were less inhibitory. These findings are consistent with a major role for arachidonic acid metabolites in the generation of light. Modulation of monocyte Fc-mediated chemiluminescence also occurred by preincubation of the cells with Fc ligands. While IgG aggregates and monomeric IgG blocked Fc-dependent chemiluminescence, IgG Fc fragments were stimulatory of this response.     

The development of the female accessory gland in the insect Rhodnius prolixus

The specialized cell types and two distinct regions of the adult Rhodnius prolixus cement gland develop from a simple pseudostratified epithelial tube during the 20–22 days of the fifth stadium. Feeding initiates the first phase, proliferation. Cells round up and divide tangentially to the lumen. Following the proliferation phase, differentiative mitoses occur and differentiation, resulting in secretory units (consisting of a ductule, gland cell and cuticular lining), ensues in the distal region. Ductule morphogenesis occurs without pseudocilia, thus differing from other insect glands. The complex changes in cell shape and interaction occur during development of the secretory unit. The secretory cell and end-apparatus develop from a double cell unit at the base of elongating ductules. The inner cell produces a complex end-apparatus of epicuticle that mirrors the microvillar pattern and then it degenerates. The ductules are lined by cuticulin and inner epicuticle while the central gland lumen has a layer of endocuticle as well. The epithelium of the proximal region remains simple producing the thick corrugated cuticle characteristic of the adult secretory duct. The mesodermal covering forms a thick longitudinal striated muscle layer that adheres to the epithelium via desmosomes.     

Luteolytic potencin in a novel prostaglandin analogue

Estrus induction in cycling sows with exogenous prostaglandin is hindered by the extended refractory period and resistance of swine to the luteolytic action of PG's. The luteolytic potency of a novel PGF_2α analogue, Schering ZK 71677, was assessed at four different dosages in chronically cannulated cycling swine. Dosages totalling 1, 1.5, 3 and 10 mg of ZK 71677 were split into two injections given intramuscularly on day 13 of the estrous cycle. Onset of behavioural estrus and serum levels of progesterone and PGF metabolite were monitored. The three lowest doses did not advance estrus but did cause a transitory decline in serum progesterone concentration on day 13. The 10 mg level advanced estrus in three of four sows although the overall mean cycle length did not differ from pretreatment cycles (18.5 ± 1.3 vs 21.3 ± 0.6 days). Progesterone values droppd steadily in all four sows in the 10 mg treatment group. No level of ZK 71677 affected serum levels of PGF metabolite. The highest level tested of PGF_2α analogue ZK 71677 elicited an uninterrupted decline in serum progesterone concentrations but was inconsistent in its ability to promote early onset of behavioural estrus in swine.     

Soluble mediators produced by a human continuous B-lymphoblastoid cell line

The Ebstein-Barr virus-transformed human lymphoblastoid cell line PGLC-33H releases a migration inhibitory factor (MIF) of MW ~ 20,000 daltons. This MIF may appear free in serum-free culture supernatants or may be associated with a carrier material as a complex of MW ~ 60,000 daltons, from which the MIF can be dissociated. The free form of MIF possesses, or is associated with a suppressor activity for pokeweed mitogen-induced immunoglobulin synthesis. This suppressor activity is heat (56 °C) and acid pH stable but 2-mercaptoethanol sensitive and cannot be attributed to α-interferon or lymphotoxin.     

Development and cellular differentiation of an insect telotrophic ovary (Rhodnius prolixus)

Differentiation events accompanying the larval-adult ovarian transformation in Rhodnius prolixus can be divided into three phases: proliferative phase (unfed to 3 days post-feed or DPF), early differentiation phase (9–15 DPF) and late differentiation phase (16 DPF to moult at 21 DPF). Ovarioles remain morphologically larval until feeding initiates development. The unfed ovariole contains germ cells surrounding a central trophic core region with the ‘germarial lumen’ occupying the basal region of the tropharium immediately above the pre-follicular tissue. Mitosis of germ cells during the proliferative phase results in a progressive increase in tropharial size with no differentiation of tissues. Regional specialization within the ovariole marks the beginning of the early differentiation phase. A zone of oocytes is established at the base of the tropharium with nuclei containing synaptonemal complexes and condensing chromosomes. Nurse cell differentiation is characterized by nucleolar elaboration and nucleo-cytoplasmic transport, the cytoplasm becoming rich in ribosomes. Autoradiographic results suggest that functional nurse cell-oocyte divergence occurs concurrently with morphological divergence. Pre-follicular tissue is divided into apical and basal zones with apical zone differentiation occurring during early and late differentiation phases.