Space and Shelter Requirement of Nymphs in the Mass-Rearing of the Edible Ruspolia differens (Orthoptera: Tettigoniidae).

The ability to mass-rear insects in high densities is a precondition for the edible insect industry but the space requirement has to be determined specifically for each species. Mass-rearing methods for Ruspolia differens Serville (Orthoptera: Tettigoniidae), one of the most consumed edible insect species in East Africa, are currently lacking. Though, these methods are urgently needed to enhance the food security in the region and to reduce the pressure on the wild populations. Here, we experimentally evaluated the effect of rearing density and rearing environment on the survival of R. differens nymphs. We conducted two experiments; in Experiment 1 we used small 0.15-liter rearing containers and in Experiment 2, larger 0.75-liter containers. The rearing densities ranged from 4 to 300 individuals per liter and we used three different rearing environments ('net', 'spikes', and 'oat sprouts'). We found that the survival of R. differens nymphs is strongly density-dependent. The suitable rearing density for young R. differens nymphs should be ≤36 nymphs per liter, as in higher densities the mortality of nymphs increases rapidly over the course of time. With rearing densities ≤36 nymphs per liter, a survival rate of 60% can be expected up to 28 d after rearing. The studied environments only had a minor effect on the survival. These results create the basis for the efforts to upscale the rearing of R. differens in the future.

Phenolic glycosides govern the food selection pattern of willow feeding leaf beetles.

The relationship between the food selection of four leaf beetle species (Phratora vitellinae, Plagiodera versicolora, Lochmaea capreae, Galerucella lineola) and the phenolic glycosides of willow (Salix spp.) leaves was tested in laboratory food choice experiments. Four willow species native to the study area (Eastern Finland) and four introduced, cultivated willows were tested.The willow species exhibited profound differences in their phenolic glycoside composition and total concentration. The food selection patterns of the leaf beetles followed closely the phenolic glycoside spectra of the willow species. Both the total amount and the composition of phenolic glycosides affected the feeding by the beetles. Phenolic glycosides apparently have both stimulatory and inhibitory influences on leaf beetle feeding depending on the degree of adaptation of a particular insect. Very rare glycosides or exceptional combination of several glycoside types seem to provide certain willow species with high level of resistance against most herbivorous insects. Analogously the average absolute amount of leaf beetle feeding was lower on the introduced willows than on the native species to which the local herbivores have a good opportunity to become adapted.

Increased CO2 and nutrient status changes affect phytomass and the production of plant defensive secondary chemicals in Salix myrsinifolia (Salisb.).

The effect of CO2 enrichment (700 and 1050 ppm) on phytomass, soluble sugars, leaf nitrogen and secondary chemicals of three Salix myrsinifolia clones was studied in plants cultivated at very poor (sand seedlings) and moderate (peat seedlings) nutrient availability and under low illumination. The total shoot phytomass production of sand scedlings was less than 10% of that of the peat seedlings. Carbon dioxide increased the total shoot phytomass of peat seedlings. When the ambient carbon supply was doubled (to 700 ppm) the growth of sand seedlings was slightly enhanced but 1050 ppm CO2 gave growth figures similar to those at the control CO2 level. Leaf nitrogen content and total soluble sugar contents were significantly higher in peat seedlings than in sand seedlings. Leaf nitrogen showed a decreasing trend in relation to CO2 increase. On the other hand, CO2 did not have any clear-cut effect on total sugars. At the control CO2 level the content of salicortin, which is a dynamic phenolic, was higher in the peat seedlings than in the sand seedlings, but salicin showed the opposite trend. CO2 enrichment considerably decreased these phenolics in the peat seedlings. At the control CO2 level, the content of more static phenolics, such as proanthocyanidins, was higher in sand seedlings. An increased carbon supply considerably increased static phenolics in the peat seedlings. Willow defence against generalist herbivores is moderately decreased by enhancement of atmospheric carbon dioxide.

Why does the bud-galling sawfly, Euura mucronata, attack long shoots?

The bud-galling sawfly, Euura mucronata, attacked longer shoot length classes on its host, Salix cinerea, more frequently than shorter shoots. Shoot length accounted for 76 to 93 percent of the variance in number of galls per 100 shoots in three habitats: forest, watermeadow, and lakeside. The reasons for this pattern were addressed with studies on shoot length in relation to: 1. Number of resources (buds) per shoot; 2. Success in establishment of larvae in galls; 3. Gall size and resources per gall; and 4. Survival of larvae after establishment as influenced by plant resistance and natural enemy attack. The most important factors proved to be success in establishment of larvae, with percent of variance accounted for ranging from 57 to 77 percent in three of four sites where relationships were significant, and survival after establishment of larvae, with variance accounted for ranging from 40 to 54 percent in the same three sites. The pattern of survival was dictated by plant resistance and not by natural enemies. These two additive factors resulted in a general relationship across all sites of increasing emergence of fully developed larvae per cohort as shoot length increased, accounting for 78 percent of the variance. These adaptive advantages to attacking longer shoots are sufficient to account for the pattern of increased probability of shoots being attacked as they increase in length.

Plant age and attack by the bud galler, Euura mucronata.

As ramets of the willow, Salix cinerea L. (Salicaceae) aged shoot length decreased in the six populations studied in S.E. Finland. Many traits correlated positively with shoot length: basal diameter, number of internodes, internode length, leaf size, and length of growing period. The bud-galling sawfly, Euura mucronata (Hartig) Man. (Churchill) (Hymenoptera: Tenthredinidae), responded positively to shoot length or correlated traits, and negatively to ramet age in three forest populations. This herbivore attacked the most vigorous plants in a population, and numbers of attacks declined as ramets aged and senesced. The generality of this kind of herbivore response to plant quality is emphasized.

Phenolic compounds of willow bark as deterrents against feeding by mountain hare.

Overwintering mountain hares (Lepus timidus) fed selectively on the shoots of a number of northern willow (Salix spp.) species. The hares preferred certain species over others and mature shoots over juvenile ones. There was a negative correlation between the phenolic glycoside concentration in the twigs and the hares' feeding. This correlation was substantiated by feeding experiments in which oat grains treated with purified phenoglycoside and catechin fractions of willow bark were offered along with untreated control oat grains to free-ranging mountain hares. Both fractions in concentrations normally found in willow twigs inhibited hare feeding. The results suggest that these phenolic compounds play a crucial role in the building up of resistance patterns among the willows. The decline in resistance in mature shoots of tall willows indicates that the juvenile resistance can be, perhaps secondarily, an adaptation against mammals browsing from ground level. Accordingly, low willow species retain a high level of resistance also in maturity.

Diaphragmatic movement using ultrasound during spontaneous and mechanical ventilation: effect of tidal volume.

Using ultrasound (US) the effect of various tidal volumes on the movement of ventral, dome and dorsal parts of the right hemidiaphragm was studied, both during spontaneous and mechanical ventilation. Six healthy non-medicated volunteers who were in the supine position breathed spontaneously shallowly (tidal volume (VT) being 400 ml) (SB), and deeply (VT 1000 ml) (SB-deep). In addition, they were mechanically ventilated with intermittent positive pressure ventilation at three different VT's: 500 ml (IPPV-500), 1000 ml (IPPV-1000) and 1700 ml (IPPV-1700). The maximal movement was recorded in the ventral part in 2 volunteers during SB, in 3 during SB-deep, and in 3 and 5 subjects during IPPV-500 and IPPV-1700, respectively. The movement in dome was 100% during SB (all others standardized to this), 303 +/- 107% during SB-deep, 82 +/- 30% during IPPV-500, 165 +/- 70% during IPPV-1000 and 266 +/- 153% during IPPV-1700. An increased tidal volume is associated with an increase in the diaphragmatic movement studied by US. However, a larger VT is needed during mechanical ventilation to achieve the same amount of change as occurred with deep spontaneous breathing.

Surfactant abnormality after endotoxin-induced lung injury in guinea-pigs.

Endotoxin (30 mg/kg) or saline was given endotracheally to guinea-pigs in order to investigate surfactant function in respiratory failure. Six hours later, bronchoalveolar lavage was performed. The lavage was analyzed for protein, phospholipids and surface activity, and fractioned into the phospholipid-rich sediment and the phospholipid-poor supernatant. The latter fraction was analyzed for surfactant inhibitor activity. After endotoxin, PaO2 and static lung-thorax compliance decreased. The lavage from endotoxin-treated animals revealed a 180% increase in protein, a 52 67% decrease in surfactant phospholipids, and increased minimum surface tension, as compared to the controls. After endotoxin, the supernatant contained a 58% higher activity of surfactant inhibitor, and the sediment had slower surface adsorption than after saline. We propose that abnormal surfactant function is important in the pathogenesis of respiratory failure in high-permeability pulmonary edema.

The significance of hypoxemia with low inspired O2 fraction before extubation.

Arterial and transcutaneous O2 (PtcO2) and CO2 (PtcCO2) tensions, arterial O2 saturations (SaO2) and P50 values were measured in 47 patients before extubation. In order to unmask ventilation to perfusion (VA/Q) inequality, all variables were obtained without CPAP and with FIO2 of 0.40 as well as with CPAP of 5 cm H2O and FIO2 of 0.40, 0.35, 0.30, 0.25, and 0.21. Eighty to 90% of the patients had PaO2/FIO2 lower than 300 torr and no significant difference in PaO2 or SaO2 was found between those who were successfully extubated (group S, n = 38) and those who required reintubation (group R, n = 9). On the other hand, the patients in group R had significantly lower P50 values, and their PtcO2 values decreased at a greater incline with the lowering of FIO2 than those in group S. Pulmonary dysfunction does not solely explain the need for reintubation in group R. It is obvious that arterial hypoxemia may become more dangerous when the patient has a low P50, anemia, or hypermetabolism. Because PtcO2 seems to uncover these factors, it is a valuable method for predicting the patient's condition before extubation.

The effect of the sample preparation method of extractable phenolics of Salicaceae species.

The effect of different tissue prehandling methods on the phenolic content of willow bark, leaves, and twigs was studied. The phenolics were extracted at room temperature, purified, and analyzed by high resolution capillary gas chromatography. Neither oven-drying at a low temperature nor room-drying of fresh leaves and oven-drying of bark produced any qualitative changes in the glucoside composition and only a minor binding effect was seen on the amounts of each glucoside. On the other hand, oven-drying of the intact long twigs and room-drying of the bark are prehandling methods to avoid. Freeze-drying or immediate analysis of frozen leaves lowered the total amount of glucosides and caused considerable qualitative changes to the glucoside composition. 80% acetone was found to be slightly more effective and gentle extraction solvent for all glucosides compared with methanol.

Can central venous blood replace mixed venous blood samples?

To estimate the value of central venous blood as representative of real changes in pulmonary shunt (Qsp/Qt), mixed venous oxygen saturation and arteriovenous oxygen content difference [C(a-v)O2] during active phases of adult intensive care therapy, 86 blood samples were withdrawn from 42 patients as quadruple simultaneous collections from systemic artery, pulmonary artery (PA), superior caval vein (CV) and right atrium (RA). We found a significant positive correlation of the measured variables and especially of the subsequent changes of these variables in individual patients between PA blood samples and both CV and RA blood samples (p less than 0.001). We, therefore, conclude that a central venous catheter can replace the PA catheter to collect blood representative of mixed venous blood samples for the above purposes. However, the exact numerical value of mixed venous blood samples can only be measured from blood collected from the PA itself.

Extubation criteria after weaning from intermittent mandatory ventilation and continuous positive airway pressure.

The "traditional" weaning criteria, arterial blood gases, and a number of other physiologic variables were measured in 47 patients to evaluate to what extent reduced ventilatory reserves or extrapulmonary organ dysfunction affect successful extubation. All patients had been weaned from continuous positive airway pressure (CPAP) and from mechanical ventilation according to the intermittent mandatory ventilation (IMV) method; at the time of study, all patients had compromised arterial oxygenation relieved by supplemental inspired oxygen. No significant difference between patients successfully extubated and those who required reintubation was found using the traditional weaning criteria or blood gases. On the other hand, patients who required reintubation had significantly lower urine volume (p less than 0.01), lower respiratory quotient values (p less than 0.05), and a higher incidence of positive blood culture (p less than 0.05). These 3 variables also correlated best to the patients' outcome after extubation.

Airway pressure release ventilation by mask.

A 53-yr-old woman with mediastinitis after thymectomy for myasthenia gravis was successfully mechanically ventilated with airway pressure release ventilation (APRV), which was started when the patient was intubated and continued by mask for 2 days after extubation. Mask APRV allowed efficient mechanical ventilation.

Composition and function of pulmonary surfactant in adult respiratory distress syndrome.

There is a severe defect in the surfactant system in adult respiratory distress syndrome (ARDS). According to animal studies oxidant injury acutely alters the synthesis and secretion of surfactant. Plasma-derived surfactant inhibitors cause an early decrease in surface activity in high permeability lung oedema. Alveolar inflammation severely disturbs the surfactant system as a result of enzymatic breakdown of its components and inhibition of surfactant function. Analysis of bronchoalveolar lavage fluid obtained following unilateral irradiation of the lung revealed a striking increase in inhibitory serum proteins and a decrease in surfactant components (SP 35 apoprotein, phosphatidylglycerol, saturated phosphatidylcholine), before appearance of irradiation pneumonitis. In lysinuric protein intolerance (LPI), an autosomal recessive disorder in renal-intestinal-hepatic diamino acid transport, there is an increased risk of ARDS. In asymptomatic LPI the concentration of diamino acids in alveolar epithelial lining was strikingly increased, suggesting that the basolateral epithelial transport defect additionally involves alveolar epithelium and predisposes to ARDS.

Differences in host use efficiency of larvae of a generalist moth, Operophtera brumata on three chemically divergent Salix species.

The food selection, growth, and fecundity of insect herbivores are largely dictated by the chemical composition and nutritive values of plant foliage. We studied the host-use efficiency of larvae of the generalist moth, Operophtera brumata (Lepidoptera: Geometridae) on three chemically divergent but nutritively similar willows (Salix spp.). The 4th instars were able to use the salicylate-free leaves of S. phylicifolia efficiently. Growth was slightly reduced on S. pentandra, which contained a moderate level of acetylated salicylates. The high concentration of salicylates found in the leaves of S. myrsinifolia seemed to provide efficient protection against non-specialized O. brumata. We also studied assimilation of nutrients and degradation of salicylates and other secondary compounds in the digestive tract of O. brumata larvae. Neither the assimilation of nitrogen nor of carbon were affected by secondary chemicals of ingested food. Salicylates were shown to be degraded to salicin and catechol, while further degradation of salicin to saligenin was rather slow. In an artificial diet experiment, we showed that two degradation products of salicylates, catechol and saligenin markedly reduced the growth of the larvae. Neither salicin nor chlorogenic acid affected larval growth. We conclude that salicylates reduced the growth of the generalist winter moth mainly by feeding deterrence caused by 6-hydroxy-2-cyclohexenone and catechol. Compared to the deleterious effects of salicylates the effects of other secondary compounds were minor.

Importance of phenolic glucosides in host selection of shoot galling sawfly,Euura amerinae, onSalix pentandra.

The effects of phenolic glucosides on the oviposition behavior ofEuura amerinae L. (Hymenoptera: Tenthredinidae) were tested in multiple oviposition experiments using different shoot length categories ofSalix pentandra L. (with different amounts of phenolic glucosides) and in experiments with pure phenolic glucosides (salidroside, arbutin, salicin, 90% salicortin, 90% 2'-O-acetylsalicortin) or composite total fractions of phenolic glucosides from three willow species (S. pentandra, S. myrsinifolia Salisb.,S. triandra L.). This was the first time that the effects of pure phenolic glucosides on the oviposition behavior of sawfly species were tested. Total fraction of phenolic glucosides fromS. pentandra and its main individual glucoside, 2'-O-acetyl-salicortin, stimulated the strongest ovipositional behavior inE. amerinae. The results show clearly that females ofE. amerinae can recognize and choose their host willow,S. pentandra, on the basis of phenolic glucosides. Moreover, they are probably able to use phenolic glucosides as a cue in shoot selection within host-plant individuals.

Ventilatory pattern in respiratory failure arising from acute myocardial infarction. II. PtcO2 and PtcCO2 compared to Pao2 and PaCO2 during IMV4 vs IPPV12 and PEEP0 vs PEEP10.

Transcutaneous oxygen and carbon dioxide tensions (PtcO2 and PtcCO2) were compared with PaO2 and PaCO2 values in 9 patients with pulmonary edema due to acute myocardial infarction (AMI) measured during four experimental interventions: (a) intermittent mandatory ventilation (IMV) 4/min + PEEP0 (cm H2O); (b) intermittent positive pressure ventilation (IPPV)12 + PEEP0; (c) IMV4 + PEEP10; and (d) IPPV12 + PEEP10. PtcO2 responded rapidly to the institution of PEEP, the rise correlating well with that in PaO2 both on IMV4 (r = 0.78) and IPPV12 (r = 0.87). On the other hand, correlations between PtcO2 vs CI and PvO2 were poor (r being 0.45 and 0.24, respectively). Transcutaneous oxygen electrode is, thus, useful in monitoring patients with post-AMI pulmonary edema, as it rapidly reflects the effects of ventilatory therapy. A nonheated PtcCO2 sensor was used in 6 patients and a heated electrode in 3 patients. With the nonheated electrode, the correlation between PaCO2 and PtcCo2 was good (r = 0.86) in 5 patients, while r in the 3 patients with the heated electrode was 0.73. One patient having a cardiac index of 1.6 L/min . M2 showed a dissociation in PCO2 values. While PaCO2 remained unchanged, PtcCO2 rose to 73 torr and within some minutes the patient had asystole. PtcCO2 tension generally shows good correlation with PaCO2 and, thus, reflects ventilation. It may also prove to be useful in the early detection of critical low cardiac output states.

Ventilatory pattern in respiratory failure arising from acute myocardial infarction. I. Respiratory and hemodynamic effects of IMV4 vs IPPV12 and PEEP0 vs PEEP10.

Positive end-expiratory pressure of 10 cm H2O (PEEP10) was compared with zero-end-expiratory pressure (PEEP0), intermittent mandatory ventilation (IMV), 4/min, with intermittent positive pressure ventilation (IPPV), 12/min, in 9 patients with pulmonary edema due to acute myocardial infarction (AMI). Systemic and pulmonary arterial pressures, pulmonary capillary wedge pressure (PCWP) and CVP, cardiac output (CO) and blood gases were measured during these four experimental interventions, and related parameters calculated. PaCO2 was 39.3 +/- 0.9 torr during IMV4 and 36.2 +/- 1.3 torr during IPPV12, and PCWP remained between 20-30 mm Hg throughout the study. The ventilatory pattern was changed at random order with the patient serving as his own control. Both PaO2 and PaO2/F102 and VO2 increased while venous admixture (Qsp/Qt) decreased with PEEP10. Cardiac and stroke indices (CI, SI) and oxygen delivery were lower with IPPV12 than they were with IMV4. Both left and right ventricular stroke work (LVSW, RVSW) were higher on IMV4. A moderate PEEP level (up to 10 cm H2O) seems beneficial in post-AMI pulmonary edema and has no significant hemodynamic side effects. The results indicate that of the four alternatives studied, IMV4 with PEEP10 is a ventilatory pattern of choice in the respiratory management of these patients, but each individual patient may require precise titration of each modality to achieve the optimal result.

Diaphragmatic movement studied with ultrasound during spontaneous breathing and mechanical ventilation with intermittent positive pressure ventilation (IPPV) and airway pressure release ventilation (APRV) in man.

Earlier knowledge about diaphragmatic movement during mechanical ventilation is based on radiological information. Since real-time bed-side monitoring is now possible the movement of the right hemidiaphragm was studied using ultrasound (US), both during spontaneous and mechanical ventilation. Nine healthy non-medicated volunteers lying supine were exposed to the following ventilation modes in random order: 1. breathing air at ambient pressure, or 2. at 7.6 mmHg of CPAP or 3. mechanical ventilation with airway pressure release ventilation (APRV), or 4. with IPPV, by mask. The movement of the diaphragm was recorded with a US sector transducer, imaging the ventral, dome and dorsal parts. The maximal movement was detected in the dome in four volunteers during spontaneous breathing with both ambient pressure and CPAP, but in the ventral part in seven and six volunteers, respectively, during APRV and IPPV. Diaphragmatic movement can be studied with US and the findings support the earlier study, with the diaphragm shifting towards the non-dependent regions of the lungs during mechanical ventilation. In this respect APRV is similar to IPPV.