Effect of ozone on breathing in dogs: vagal and nonvagal mechanisms

We exposed two awake dogs with a chronic tracheostomy and the cervical vagus nerves exteriorized in skin loops to 1.0 ppm of ozone (O3) for 2 h at intervals of 4 wk. We measured ventilatory variables before and after O3 exposure during rest and exercise before and after vagal block. We compared the effects of vagal blockade, exercise, and O3 on the primary determinants of breathing pattern (VT/TI, VT/TE, TI, and TE) in each of three conditions: base line (steady state), during hypercapnia, and after inhalation of 1% histamine. Under base-line conditions, O3 increased respiratory rate and decreased tidal volume (VT) by shortening time of expiration (TE) and time of inspiration (TI) without affecting VT/TI, an indicator of the neural drive to breathing. During progressive hypercapnia, O3 shortened TE and TI by effects both on tonic (nonvolume-related) and on phasic (volume-related) vagal inputs, and only the latter were prevented completely by cooling of the vagus nerves. Histamine-induced tachypnea was increased by O3 and was totally blocked by cooling the vagus nerves. We conclude that O3 shortens the timing of respiration without increasing ventilatory drive, shortens TI and TE through vagal and nonvagal pathways, increases tonic nonvagal and phasic vagal inputs, and stimulates more than one vagal fiber type.     

Hemodynamics and vascular sensitivity to circulating norepinephrine in normal skin and delayed and acute random skin flaps in the pig

Cutaneous circulation in 4 X 10 cm skin samples and delayed and acute random skin flaps constructed on the flanks of castrated Yorkshire pigs (13.3 +/- 0.7 kg; n = 12) were studied during intravenous infusion (0.5 ml per minute) of 5% dextrose solution (vehicle) and 5% dextrose containing norepinephrine (1 microgram/kg per minute). Total and capillary blood flow and A-V shunt flow were measured by the radioactive microsphere technique 6 hours after the raising of 4 X 10 cm single-pedicle acute and delayed random skin flaps using the technique and calculations published previously. Fluorescein dye test was also performed to assess vascular perfusion. It was observed that the capillary blood flow in the single-pedicle delayed skin flaps was similar to that in the normal skin, and the maintenance of this normal skin blood flow was not due to the closing of A-V shunt flow in the delayed skin flaps. Similarly, the significant (p less than 0.01) decrease in capillary blood flow and distal perfusion in the acute skin flaps compared with the delayed skin flaps was not due to the opening of A-V shunts in the acute skin flaps. There was no evidence to indicate that A-V shunt flow per se was the primary factor for the regulation of capillary blood flow in the acute and delayed skin flaps in the pig. Our data seemed to indicate that tissue ischemia in the distal portion of acute skin flaps was likely the result of vasoconstriction of the small random arteries which supplied blood to arterioles and A-V shunts, and locally released neurohumoral substances may play an important role in the pathogenesis of vascular resistance and ischemia in the acute skin flaps.     

Regional specificity of anuran larval skin during metamorphosis: dermal specificity in development and histolysis of recombined skin grafts

Summary Skins from back and tail were dissected from tadpoles of Rana japonica prior to resorption of the tail and separated into epidermis and dermis by treatment with neutral protease. Homotypically and heterotypically recombined skins were constructed from the separated epidermis and dermis and transplanted into the tail of the original tadpole. Skin grafts using dermis from tail region degenerated simultaneously with resorption of the tail. However, skin grafts containing dermis from back region survived on the posterior part of the juvenile frog beyond metamorphosis. Furthermore, all epidermis underlaid with dermis from back region formed secretory glands and became flattened epithelia characteristic of adult back skin, regardless of region from which the epidermis came. Even when epidermis isolated from tail skin was cultured inside a back skin graft, the tail epidermis survived forming an epithelial cyst and developed secretory glands. These results suggest that regional specificities of anuran larval skin, i.e., development of back skin and even histolysis of tail skin, are determined by regionally specific dermis. The results also suggest that some of epidermal cells of tail skin are able to differentiate into epithelial cells similar to back skin of the adult under the influence of back dermis.     

Circadian rhythms of testosterone-dependent behaviors,crowing and locomotor activity,in male Japanese quail

Summary An apparatus was devised to record crowing (mate calling by males) together with locomotor activity and recorded data was analyzed by several methods for rhythm analysis. Crowing and locomotor activity of Japanese quail held on long days were recorded during sexual development as estimated from circulating gonadotropins and testosterone. Both behaviors were testosterone-dependent but commencement of crowing preceded the increase in locomotor activity. When the two behaviors attained their maximum levels, crowing showed consistent daily rhythms in which two peaks were apparent, a major one at the onset of light and a broader one 8 hours later. Locomotor activity also showed a clear daily rhythm with a peak between the two peaks of crowing rhythm suggesting a fixed phase relationship between the two rhythms.Both rhythms free-ran under constant dim light with periods shorter than 24 h. They persisted in birds which had been castrated and then supplied with exogenous testosterone via implanted Silastic capsules. The durations of both rhythms were quite comparable to each other and they maintained a fixed phase relationship similar to that found under LD cycles.The results indicate that testosterone is essential for the induction of crowing and for the enhancement of locomotor activity but the formation of the rhythms in behavior was strictly dependent on a circadian oscillatory mechanism.Abbreviations LH luteinizing hormone - FHS follicle-stimulating hormone - LD light-dark - LDim light-dim light     

Effect of 5-azacytidine on the differentiation of human leukemia K-562 cells

The treatment of K-562 cells with 10(-5) M to 10(-7) M 5-azacytidine induced a marked increase in benzidine-positive cells. Similarly, the exposure of K-562 cells to 2 X 10(-3) M butyric acid or 5 X 10(-7) M 1-beta-arabinofuranosylcytosine or 1 X 10(-3) M hydroxyurea induced an erythroid differentiation of K-562 cells. The activity of DNA-methyltransferase and the level of methylcytosine in newly synthesized DNA were significantly decreased when the cells were treated with 5-azacytidine or butyric acid, while 1-beta-arabinofuranosylcytosine or hydroxyurea had no inhibitory effect on DNA-methylation of K-562 cells. These results suggest that the inhibition of DNA-methylation is not necessarily a specific phenomenon for erythroid differentiation of K-562 cells.     

Flavonoids in the leaves of twenty-eight polygonaceous plants

Flavonoids in the leaves of twenty-eight species belonging to the Polygonaceae were studied. Thirty-three kinds of flavonoids were isolated, and eighteen kinds were obtained as crystals. Quercetin glycosides were commonly found in the family. In the quercetin glycosides, 3-O-rhamnoside was most frequently found: 3-O-glucuronide is also distributed widely. Myricetin glycosides were rare. Methylated flavonols were found in some species of the sectionsEchinocaulon andPersicaria. Eleven kinds ofC-glycosylflavones were found in the present survey, andC-glycosylflavones were distributed in all species of the genusRheum and in almost all species of the section Tiniaria.Rumex Acetosella andPolygonum suffultum are exceptional, the former contains flavone glycoside and the latterC-glycosylflavones only, as main components.     

Crystallographic studies of the chicken gizzard G-actin X DNase I complex at 5A resolution

The structure of the chicken gizzard G-actin X DNase I complex has been determined at 5 A resolution by an X-ray diffraction method. Protein phases were computed by the multiple isomorphous replacement method using four heavy atom derivatives. The mean figure of merit was 0.65. Dimensions of the three molecular species, the complex, G-actin and DNase I, were determined based on the "cypress wood" models derived from the electron density map. The natures of the heavy atom binding sites are discussed in relation to the distinction between the two component molecules. The pattern of successive contacts between actin molecules observed in the present crystal seems unrelated to that found in F-actin.     

Measurement of receptor-independent metabolism of low-density lipoprotein. An application of glycosylated low-density lipoprotein

Incubation of human low-density lipoprotein (LDL) with glucose results in a nonenzymatic formation of a Schiff base between the monosaccharide and lysyl residues of apolipoprotein B. Increasing the percentage of lysyl residues of apolipoprotein B modified by glycosylation decreases the fractional catabolic rate of the glycosylated LDL, and decreases the metabolism of the glycosylated LDL by human skin fibroblasts. The glycosylated LDL, containing 20-40% of total lysyl residues of apoprotein B modified, was metabolized at a slow rate by both human skin fibroblasts and mouse peritoneal macrophages. These results led to the suggestion that glycosylated LDL is primarily catabolized via a receptor-independent process. Assuming LDL catabolism occurs via receptor-dependent and receptor-independent processes, the ratio of (fractional catabolic rate of glycosylated LDL)/(fractional catabolic rate of native LDL) should be an estimate of the percentage of LDL catabolism via the receptor-independent process. From the fractional catabolic rates of glucose-LDL (20-40% of lysyl residues modified) and galactose-LDL (30-60% of lysyl residues modified) 41% and 30% respectively, of LDL catabolism occurred by a receptor-independent process.     

Phytohemagglutinin induces rapid degradation of phosphatidylinositol 4,5-bisphosphate and transient accumulation of phosphatidic acid and diacylglycerol in a human T lymphoblastoid cell line, CCRF-CEM

The human T lymphoblastoid cell line designated CCRF-CEM responds to phytohemagglutinin with a 3.7-fold enhancement of the 32PO4 incorporation into phosphatidylinositol. In myo-[2-3H]inositol-prelabeled CCRF-CEM cells, phytohemagglutinin induced a 3.3-fold accumulation of myo-[2-3H]inositol phosphate during 15 min incubation at 37 degrees C in the presence of 5 mM LiCl. Since Li+ is a potent inhibitor of myo-inositol-1-phosphatase, the results indicate that phytohemagglutinin induces the hydrolysis of inositol lipids in CCRF-CEM cells. In 32PO4-prelabeled CCRF-CEM cells, phytohemagglutinin induced a breakdown of 28% of [32P]phosphatidylinositol 4,5-bisphosphate 40-60 s after the stimulation. The decrease of [32P]phosphatidylinositol 4,5-bisphosphate was found as early as 10 s after the stimulation. This decrease was followed by an increased 32P-labeling of phosphatidic acid. In [2-3H]glycerol-prelabeled CCRF-CEM cells, phytohemagglutinin induced a transient accumulation of [3H]phosphatidic acid and [3H]diacylglycerol. The amount of [3H]phosphatidic acid in the stimulated cells was 3.7-times the control value at 2 min after the stimulation, whereas the amount of [3H]diacylglycerol in the stimulated cells was 1.5-times the control value at 5 min after the stimulation. In [3H8]arachidonate-prelabeled CCRF-CEM cells, phytohemagglutinin induced a transient accumulation of [3H]phosphatidic acid; the amount was 2.5-times the control value at 2 min after the stimulation. Quinacrine (1 mM) caused 41% reduction in the amount of [3H]phosphatidic acid accumulated by the stimulation in [2-3H]glycerol-prelabeled cells. Stimulation in a Ca2+-free saline containing 1 mM EGTA caused 53% reduction in the amount of [3H]phosphatidic acid accumulated by the stimulation. The results presented in this paper indicate that a human T lymphoblastoid cell line, CCRF-CEM, responds to phytohemagglutinin with a rapid turnover of inositol lipids.