Failure to detect infection in fallow deer (Cervus dama) exposed to Theileria cervi from white-tailed deer

A frozen stabilate was produced from Theileria cervi sporozoites in salivary glands of adult Amblyomma americanum. The stabilate was inoculated into three fallow deer (Cervus dama) and two white-tailed deer (Odocoileus virginianus). Following inoculation, the white-tailed deer developed parasitemias as determined by blood smear examination at 11 and 13 days postexposure. Repeat examination of blood from the three fallow deer for 30 days postexposure failed to reveal observable piro-plasms. These findings indicate that fallow deer are not as susceptible to the Theileria cervi found in white-tailed deer from North America. Thus, there are some questions regarding the taxonomic position of this organism.     

Atp-activated ionic permeability in smooth muscle cells isolated from the guinea pig urinary bladder

Smooth muscle cells from the guinea pig urinary bladder were investigated by voltage clamping at the plasma membrane and using an intracellular perfusion technique. Applying adenosine triphosphate (ATP) at a concentration greater than 3 × 10^–8 M and at a membrane potential of –100 to –30 mV produced a rise in fast inward transmembrane current. A similar effect was exerted by adenosine diphosphate (ADP) and -, -, and ,-methylene ATP. Application of guanosine triphosphate, inosine triphosphate, adenosine monophosphate (AMP), and adenosine failed to activate this current. It was found that AMP blocks ATP receptors competitively. No pharmacological differences were found between the latter ATP receptors and those of rat sensory neurons. The ATP receptors were rapidly desensitized and recovered their sensitivity to agonists extremely slowly. Speed of desensitization was reduced by a decrease in ATP concentration.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 19, No. 1, pp. 95–100, January–February, 1987.     

Fibronectin-degrading proteases from the membranes of transformed cells

The local degradation of fibronectin substrata by Rous sarcoma virus-transformed chick embryonic fibroblasts requires cell-contact-related metalloendoprotease and serine-protease activities. Using fibronectin-containing SDS gels, two large proteases with apparent molecular weights of 120K and 150K were found only in the membrane fraction of transformed cells and were absent in normal cells. Both 120K and 150K proteases were active at neutral pH, but showed preferential inhibitor sensitivities of serine and metal proteases, respectively. The 150K protease appeared to account for most of the proteolytic activity since metalloendoprotease inhibitors completely blocked proteolytic activity of the 150K in fibronectin gels, more than 80% of the fibronectin-degrading activity of solubilized membranes, and largely suppressed the appearance of fibronectin degradation spots in cultures of transformed cells.     

Transpososomes: stable protein-DNA complexes involved in the in vitro transposition of bacteriophage Mu DNA

We report that two types of stable protein-DNA complexes, or transpososomes, are generated in vitro during the Mu DNA strand transfer reaction. The Type 1 complex is an intermediate in the reaction. Its formation requires a supercoiled mini-Mu donor plasmid, Mu A and HU protein, and Mg2+. In the Type 1 complex the two ends of Mu are held together, creating a figure eight-shaped molecule with two independent topological domains; the Mu sequences remain supercoiled while the vector DNA is relaxed because of nicking. In the presence of Mu B protein, ATP, target DNA, and Mg2+, the Type 1 complex is converted into the protein-associated product of the strand transfer reaction. In this Type 2 complex, the target DNA has been joined to the Mu DNA ends held in the synaptic complex at the center of the figure eight. Supercoils are not required for the latter reaction.     

Vaginal treatment with a prostaglandin F2 alpha derivative (alfaprostol) for inducing labor in pregnancy at term

The effectiveness and acceptability of Alfaprostol (an analog of PGF2 alpha) in inducing labor were assessed in 20 pregnant women at term. All subjects had no spontaneous uterine activity before treatment and the mean (M +/- SE) Bishop score was 2.45 +/- 0.21. The drug was administered by vaginal route at the dose of 10 mg every 3 hours. Regular uterine contractions appeared in all patients and delivery occurred in 85% of the patients after a mean time of 9h50min +/- 0h55min following the start of treatment. The mean dose of Alfaprostol utilized to achieve delivery was 29.4 +/- 2.0 mg. No major side effects were noted in the mothers and their fetuses at any time during treatment. Two patients exhibited vomiting. The Apgar score of all newborns at birth was 8 or more. These results suggest the usefulness of Alfaprostol to induce labor in pregnant women at term, as it has oxytocic activity without adverse effects on either the mother or the fetus.     

Critical considerations in the development of an assay for sulfidopeptide leukotrienes in plasma

A sensitive and specific assay has been developed for measurement of total sulfidopeptide leukotrienes (LT) in plasma. LTC4 and LTD4 in plasma are converted to LTE4 which is then extracted by C18 Sep-Pak binding and elution. Total LTE4 is resolved by reverse phase high performance liquid chromatography (RP-HPLC) and quantitated by radioimmunoassay (RIA). A [3H]LTE4 internal standard is added to the starting plasma sample to allow overall recovery to be calculated and to define the fractions from RP-HPLC to be assayed for LTE4-like immunoreactivity. The correlation between the measured increase in LTE4 concentration after addition of incremental amounts of LTC4 and LTE4 to plasma was 0.989 and 0.978, respectively, with slopes of 1.05 and 1.11. Addition of 51 pg/ml LTE4 to 5 ml plasma was detectable; the measured increase was 48 +/- 12 pg/ml (mean +/- SE, n = 7). The intra-assay coefficient of variation for 341 pg/ml of added LTC4 was 3.2% (n = 6). Sulfidopeptide leukotrienes could not be detected in blood samples taken from 12 normal volunteers in whom the theoretical detection limit, calculated from the sensitivity of the RIA, the overall recovery of LTE4, and the volume of plasma extracted, was 83 +/- 4 pg LTE4/ml plasma (0.19 +/- 0.01 pmol sulfidopeptide leukotriene/ml plasma; mean +/- SE).     

Age-specific Chaoborus predation on rotifer prey

SUMMARY. 1. This is the first study to examine predator-prey interactions between Chaoborm instars and rotifer prey. The predatory behaviour of instars I–III of Chaoborus pimctipennis and the diet selectivity of instars I—IV feeding on rotifers were examined in the laboratory. Prey used in direct observations of predatory behaviour included a variety of rotifers (Symhacta pectlnata, S. ohUmga, Polyarthra remata, Asplanchna girodi, Keratella crassa, spined and unspined forms of Keratella cochlearis) and two crustaceans (Bosmitia longirostris, Mesocyclops edax nauplii. 2. In general, strike efficiencies (percentage of strikes resulting in inges- tion) increased in successive instars I—III. Early instar (I and II) strike efficiencies were low when compared with other invertebrate predators. For a given instar. mean prey handling times varied among prey species more than strike efficiencies. Mean handling times for small, soft-bodied rotifers were lowest and those for wide, hard-bodied prey were highest. 3. Instar I exhibited significantly greater selectivity for the small, soft- bodied S. obUmga than for the larger S. pectinata, hard-bodied K. crassa, and spined and unspined forms of K. cochlearis. Instars II—IV positively selected both the large and small Symhaeta species over all Keratella species. The relationship between Chaobortts selectivity and prey value (weight of prey per unit handling time) can be described by a power function. Ingestion rates of rotifers by older instars (III and IV) are among the highest reported for invertebrate predators. 4. Rotifer vulnerability to Chaoborus predation probably depended on rotifer cuticle texture, body width, and hydrodynamic disturbances. Spined rotifers were not necessarily protected from Chaoborus predation because Chaohorus can manipulate and swallow them. Giguere et al.'s 1982) encounter rate model must be modified to predict encounter rates of slow-moving rotifer prey with Chaohorus.     

Tracheostomy Tube Failure in Obstructive Sleep Apnea

In our institutions we routinely do posttracheostomy sleep studies on patients being treated for obstructive sleep apnea. We have identified several patients who failed to show objective evidence of improvement after tracheostomy. From our studies we have found that both mechanical obstruction and concomitant respiratory control dysfunction caused this failure. A unique tracheostomy tube was constructed to treat the subset of patients with internal collapse of the tracheostomy tube.     

An abnormal terminal X-Y interchange accounts for most but not all cases of human XX maleness

To determine if human XX maleness results from an abnormal chromosomal X-Y interchange, we studied the inheritance of the paternal pseudoautosomal region in nine patients. Those six patients in whom Y-specific DNA was found (Y(+)) inherited the entire pseudoautosomal region from the paternal Y chromosome and lost that of the paternal X chromosome. Moreover, in three Y(+) cases, we observed the deletion of a paternal Xp locus tightly linked to the pseudoautosomal region. These results definitively show that an abnormal and terminal X-Y interchange during paternal meiosis causes Y(+)XX maleness. In contrast, no abnormal X-Y interchange was observed in any of the three Y(-) cases analyzed, suggesting that maleness can occur in the absence of any Y-specific DNA.     

Startle responding and context conditioning. Naloxone pretreatment and stimulus intensity

The possibility that acoustic startle stimuli could support a conditional response (freezing) to contextual stimuli was investigated. Rats were exposed to three acoustic startle stimuli on the first day, and one on the second day. On day 1, 20 rats received naloxone pretreatment and another 20 received saline (placebo) pretreatment. Half of each group received a high-intensity acoustic stimulus, the other half a low-intensity acoustic stimulus. Both the higher stimulus intensity and the naloxone pretreatment led to greater freezing behavior during the 3-minute test period before the single startle stimulus on day 2. These findings support the notion that increased actual or perceived intensity of the acoustic startle stimulus increases conditioning to contextual stimuli as indexed by freezing behavior.