Detection of pulsed gamma rays above 100 GeV from the Crab pulsar.

We report the detection of pulsed gamma rays from the Crab pulsar at energies above 100 giga-electron volts (GeV) with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) array of atmospheric Cherenkov telescopes. The detection cannot be explained on the basis of current pulsar models. The photon spectrum of pulsed emission between 100 mega-electron volts and 400 GeV is described by a broken power law that is statistically preferred over a power law with an exponential cutoff. It is unlikely that the observation can be explained by invoking curvature radiation as the origin of the observed gamma rays above 100 GeV. Our findings require that these gamma rays be produced more than 10 stellar radii from the neutron star.

Tolerance of Bradyrhizobium sp. (Lupini) strains to salinity, pH, CaCO3 and antibiotics.

AIMS: Ten rhizobial isolates obtained from different locations in Egypt were examined for their ability to survive under stress conditions and their growth response to increasing levels of NaCl (1-8% w/v), pH (4-10), CaCO3 (1-10% w/v) and 12 antibiotics. METHODS AND RESULTS: All the rhizobial isolates tolerated a NaCl concentration up to 5% and were divided into two groups with respect to NaCl tolerance. The rhizobial isolates from group two showed significantly (P < 0.05) better survival under high NaCl concentration. All the tested isolates survived acidic (pH 4-5) and alkaline conditions (pH 9-10) and CaCO3 (up to 10% w/v) in liqued YEM medium. CONCLUSION: Antibiotic resistance patterns did not correlate to NaCl, pH or CaCO3 tolerance. Variations among different strains showed that there is potential to improve strain performance under stress conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: The results suggest that selection of adapted strains under stress conditions is possible and can be used as inoculants for successful lupin growth.

Reptilian melanomacrophages function under conditions of hypothermia: observations on phagocytic behavior.

Melanomacrophages (MMs) were removed from livers of turtles of three North American families and cultured. J774 mammalian macrophages were similarly cultured and the MMs were exposed to E. coli(fluor) at approximately 2, 7, 27, and 37 degrees C. At least one third of the MMs continued to function at the low temperatures where less than 2% of the mammalian cells incorporated bacteria deeply into the cytoplasm. In most instances, when the bacteria were not internalized deeply into the cytoplasm, they became stationary just inside, or within, the cell membrane. The MMs were significantly less efficient than the mammalian cells at 37 degrees C and significantly more efficient at 2 and 7 degrees C. In general, it appears that MMs are never as efficient as mammalian macrophages under the most ideal temperatures for the cell but they are capable of functioning at reasonable levels at temperature extremes. The observations are suggestive of a genetic mechanism functioning in the MMs that is rarely expressed in J774 cells under conditions of hypothermia. MMs in vitro and probably in vivo consume bacteria, fungi, attach to helminth eggs, and consume old erythrocytes.

In vitro culture of melanomacrophages from the spleen and liver of turtles: comments on melanomacrophage morphology.

Melanomacrophages were extracted and cultured from the spleen and liver of three turtle species representing three divergent families, the Chelydridae, Emydidae, and Trionychidae. Homogeneous cultures were obtained by repeatedly forcing minced, frequently washed tissue through a sterile screen and separating the resulting cells by centrifugation. The cells were surprisingly resistant to lysis and were maintained in culture for over 12 weeks where culture characteristics, appearance, and longevity from these two organs were similar. They attached to the T flask substrate as individual cells and aggregates and spread out 14 days after being placed in media. Ridges and ruffles at the distal ends of pseudopodia and the cell surface along with a zone of clearing attest to the cells' phagocytic nature. A few melanomacrophages from both organs underwent mitosis 14 days after treatment with granulocyte macrophage colony-stimulating factor but it is possible that other factors contributed to stimulation of cell division.

Difference in QT interval measurement on ambulatory ECG compared with standard ECG.

Measurement of the QT interval on standard ECG has diagnostic importance in the congenital long QT syndrome, in pharmacological therapy of arrhythmias, as well as in ischemic heart disease. It has been suggested that QT prolongation on ambulatory ECG (Holter) may have similar importance. To assess agreement between methods, QT interval measurement on standard ECG was compared to that on Holter. Simultaneously obtained ECG and Holter tracings (25 mm/s) of the same complexes in leads V1 and V5 were studied in 14 patients (age range 4-36 years). ECG pairs (n = 100, 49 V1 and 51 V5) were compared over a range of QT interval from 300-620 ms, as determined with the use of calipers by two observers blinded to pairing relationship. Correlation between methods was high for both observers (observer 1:r[V1] = 0.872, r[V5] = 0.973; observer 2: r[V1] = 0.972, r[V5] = 0.988), and interobserver variability was small (> 85% of measurements within 20 ms). As compared to ECG, Holter underestimated QT interval in V1, mean difference (QT [Holter]-QT [ECG]) observer 1 (-23 ms, P < 0.001), observer 2 (-7 ms, P < 0.05), and overestimated QT in V5, mean difference observer 1 (+13 ms, P < 0.001), observer 2 (+ 13 ms, P < 0.001). However, individual variation between methods was wide, as expressed by the difference between individual measurements (95% confidence interval [V1]: observer 1 [-99 to +53 ms] observer 2 [-47 to +33 ms]; [V5]: observer 1 [-33 to +59 ms] observer 2 [-17 to +43 ms]). Furthermore, when using the QTA (interval from onset of Q wave to apex of T wave) similar variability was observed. In the assessment of QT interval, potential sources of error of this magnitude could limit the clinical utility of ambulatory monitoring in detecting prolongation of the QT interval for diagnostic purposes.

Melanomacrophage aggregations and their age relationships in the yellow mud turtle, Kinosternon flavescens (Kinosternidae).

Microscopic examination of the pigment cell aggregations in the liver and spleen of mud turtles (Kinosternon flavescens) suggests that the morphology and behavior of these cells is consistent with the melanomacrophages described in teleost fishes and the pigmented "Kupffer cells" described in frogs and reptiles. These cells contain massive amounts of melanin, substantial lipofuscin, and some hemosiderin consistent with their phagocytic function. Similar-appearing isolated pigmented macrophages are solitary in the liver, spleen, lung, and kidney. Number and size of the largest hepatic aggregations increase almost linearly with turtle age so that in old turtles they may constitute up to 20% of the liver volume. This increase may result from hepatic recruitment of macrophages throughout the life of the turtle and suggests that size and number of melanomacrophage aggregations may serve as a marker for senescence in otherwise healthy turtles of this species.

Clinical results of pharyngeal flap surgery: the Iowa experience.

Sixty-five patients with cleft palate, with or without cleft lip, who received previous pharyngeal flap surgery for chronic velopharyngeal dysfunction in our department, were examined for velopharyngeal status, speech production patterns, and evidence of nasal airway obstruction. Of the 65 subjects, 54 (83.1 percent) showed velopharyngeal function within normal limits, 43 (66.1 percent) showed normal or near-normal speech production, and 58 (89.2 percent) reported snoring sometimes or often. Of the 58 reporting snoring, electrocardiogram (ECG) data for 33 were examined for evidence of right ventricular hypertrophy. Only one (3 percent) of the 33 showed such possible indication. We conclude that by our methods, pharyngeal flap surgery is an effective treatment for velopharyngeal dysfunction. After surgery, patients may report symptoms of nasal airway obstruction during sleep but are not expected to show ECG changes in cardiac function resulting from oxygen deprivation.

Chronotropic responses of chick atria to field stimulation after various neural crest ablations.

Three models of altered autonomic innervation of the chick heart have been developed in the last few years. These include sympathetically aneural heart, parasympathetically aneural heart, and heart with cholinergic innervation reconstituted from the nodose placodes. The neural status of these hearts has been assessed by a variety of morphological and biochemical methods, but the functional status of innervation is not known. In the present study, we have used electrocardiography and field stimulation to determine the functional neural status of the three different innervation models. The RR and QTc intervals were measured to assess the dominant autonomic tone and autonomic dysfunction in the heart. Even though the RR and QTc intervals were found to be identical in sham and experimental embryos, field stimulation of superfused atria showed that the sympathetically aneural heart has functional cholinergic innervation but lacks any sympathetic response. Hearts from embryos which were parasympathetically aneural lacked a cholinergic response to field stimulation and were judged to be functionally parasympathetically aneural. Hearts with cholinergic ganglia reconstituted from the nodose placodes have normal RR and QTc intervals as well as a normal cholinergic response to field stimulation. The results indicate that these neurons are functionally indistinguishable from neural crest-derived neurons.

Electrocardiographic QT prolongation after ablation of the nodose placode in the chick embryo: a developmental model of the idiopathic long QT syndrome.

Electrocardiographic abnormalities characteristic of the idiopathic long QT syndrome are thought to be caused by an imbalance of sympathetic activity in the heart. Recent evidence indicates that autonomic and sensory innervation density in the end-organ is modulated by reciprocal interactions. Ablation of one neuronal population allows reciprocal increases in growth of the remaining nerves. To test whether QT prolongation could be produced in chick embryos by altering sensory innervation to the heart, microcautery was used to ablate premigratory areas of the right nodose placode, a coalescence of cells in the embryonic ectoderm that generates neurons providing sensory innervation to the heart via the inferior ganglion of the vagus (nodose ganglion). After functional autonomic innervation was established, three-lead ECG were obtained in embryos with the right nodose placode ablated (experimental) and in sham-operated controls (sham) at incubation days 17-20 in a controlled temperature environment. Electrocardiograms were analyzed for RR and QT intervals. The QT interval was corrected for heart rate using the formula QTc = QT/(RR)1/2 using an average of ten complexes. Compared with shams (n = 8), experimental embryos (n = 7) had significantly longer QTc (0.339 +/- 0.005 versus 0.318 +/- 0.004), and slower heart rates (RR = 0.29 +/- 0.005 versus 0.27 +/- 0.007). These findings mimic those in children with the idiopathic long QT syndrome. Experimental manipulation of the sensory innervation to the heart in the chick embryo via the nodose placode may provide an animal model to improve understanding of the pathogenesis of the idiopathic long QT syndrome.

Additional notes on the coccidian parasites of the soft-shell turtle, Trionyx spiniferus Le Sueur, in Iowa, with a description of Eimeria vesicostieda sp. n.

Oocysts of Eimeria dericksoni Roudabush, Eimeria mascoutini Wacha & Christiansen, and Eimeria vesicostieda sp. n. were isolated from the Spiny Soft-shell Turtle, Trionyx spiniferus LeSueur, in Iowa. The sporulated oocysts of E. dericksoni are redescribed to include, for the first time, the dimensions of the sporocysts (6.0-8.5 x 3.0 5.0 micrometer) ant the structural appearance of the Stieda body (thinly convex); the oocysts of E. vesicostieda are newly described as being thick-walled, narrowly avoid to narrowly ellipsoid, measuring 22.0-25.5 x 16.5-20.5 micrometer, and having a polar granule, a sporocyst residuum, and a vesicle-like Stieda body; the oocysts of E. mascoutini are documented photographically.

Two new species of Eimeria from colubrid snakes in Iowa.

Oocysts of Eimeria natricis sp. n. and Eimeria sipedon sp. n. were isolated from 2 Northern Water Snakes, Natrix sipedon sipedon (Linnaeus), in Iowa. Oocysts of E. natricis were elongate, slightly ovoid, averaging in size 32.3 X 17.5 mum; sporocysts averaged 15.7 X 8.2 mum. Oocysts of E. sipedon were broadly ovoid averaging in size 18.0 X 15.9 mum; sporocysts averaged 12.0 X 7.4 mum. In both species, sporocyst residua were present, but micropyles, polar granules and oocyst residua were lacking.