Comparative floral development of Mir-grown and ethylene-treated, earth-grown Super Dwarf wheat.

To study plant growth in microgravity, we grew Super Dwarf wheat (Triticum aestivum L.) in the Svet growth chamber onboard the orbiting Russian space station, Mir, and in identical ground control units at the Institute of BioMedical Problems in Moscow, Russia. Seedling emergence was 56% and 73% in the two root-module compartments on Mir and 75% and 90% on earth. Growth was vigorous (produced ca. 1 kg dry mass), and individual plants produced 5 to 8 tillers on Mir compared with 3 to 5 on earth-grown controls. Upon harvest in space and return to earth, however, all inflorescences of the flight-grown plants were sterile. To ascertain if Super Dwarf wheat responded to the 1.1 to 1.7 micromoles mol-1 atmospheric levels of ethylene measured on the Mir prior to and during flowering, plants on earth were exposed to 0, 1, 3, 10, and 20 micromoles mol-1 of ethylene gas and 1200 micromoles mol-1 CO2 from 7 d after emergence to maturity. As in our Mir wheat, plant height, awn length, and the flag leaf were significantly shorter in the ethylene-exposed plants than in controls; inflorescences also exhibited 100% sterility. Scanning-electron-microscopic (SEM) examination of florets from Mir-grown and ethylene-treated, earth-grown plants showed that development ceased prior to anthesis, and the anthers did not dehisce. Laser scanning confocal microscopic (LSCM) examination of pollen grains from Mir and ethylene-treated plants on earth exhibited zero, one, and occasionally two, but rarely three nuclei; pollen produced in the absence of ethylene was always trinucleate, the normal condition. The scarcity of trinucleate pollen, abrupt cessation of floret development prior to anthesis, and excess tillering in wheat plants on Mir and in ethylene-containing atmospheres on earth build a strong case for the ethylene on Mir as the agent for the induced male sterility and other symptoms, rather than microgravity.

Silica deposition on the leaves of Mir- and Earth-grown Super Dwarf wheat.

Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) microanalysis were used to investigate the nature of crystals deposited on leaves of Mir- and Earth-grown Super Dwarf wheat (Triticum aestivum L.) plants. Leaves from these plants exhibited dense and uniformly distributed crystals on leaf abaxial surfaces when viewed by SEM. Young leaves showed that crystals initially accumulated around the stomata on the adaxial surface, but became more dense and uniformly distributed as the leaves aged. EDX microanalyses of the Balkanine (a nutrient charged clinoptilolite zeolite) medium in which the wheat plants were grown showed an elemental pattern similar to that observed on the wheat leaves. The absence of N and P in the Balkanine suggests that they were completely utilized by the plants. Only Si and O were evident in the drying agent, Sorb-it-Silica (TM), and perhaps could have accounted for some of the Si observed on the plant tissue. Grant numbers: NCC2-831, 84322-4810

Microgravity effects on water supply and substrate properties in porous matrix root support systems.

The control of water content and water movement in granular substrate-based plant root systems in microgravity is a complex problem. Improper water and oxygen delivery to plant roots has delayed studies of the effects of microgravity on plant development and the use of plants in physical and mental life support systems. Our international effort (USA, Russia and Bulgaria) has upgraded the plant growth facilities on the Mir Orbital Station (OS) and used them to study the full life cycle of plants. The Bulgarian-Russian-developed Svet Space Greenhouse (SG) system was upgraded on the Mir OS in 1996. The US developed Gas Exchange Measurement System (GEMS) greatly extends the range of environmental parameters monitored. The Svet-GEMS complex was used to grow a fully developed wheat crop during 1996. The growth rate and development of these plants compared well with earth grown plants indicating that the root zone water and oxygen stresses that have limited plant development in previous long-duration experiments have been overcome. However, management of the root environment during this experiment involved several significant changes in control settings as the relationship between the water delivery system, water status sensors, and the substrate changed during the growth cycles.

Analysis of the spaceflight effects on growth and development of Super Dwarf wheat grown on the Space Station Mir.

The hypothesis being tested is that Super Dwarf wheat, Triticum aestivum L., plants in the Svet Greenhouse onboard the Russian Space Station Mir will complete a life cycle in spaceflight, providing that the environmental conditions necessary for adequate growth on Earth are supplied. Twenty six seeds of wheat were planted in each of 2 rows of 2 root compartments for a total of 104 seeds in Svet. Germination rate at 7 d was 56 and 73% on Mir and 75 and 90% in ground-based controls. Plants were grown throughout the whole cycle of ontogenesis (123 d) with samples gathered at different times to validate the morphological and reproductive stages of the plants. Young plants showed vigorous early seedling growth, with large biomass production, including the formation of 280 floral spikes. Upon return to Earth, comparative analyses showed that the number of tillers and flowers per spikelet were 63.2% and 40% greater, respectively, in Mir-grown plants than in the controls. By contrast, the stem length (52.4%), spike mass (49.2%) and length (23.1%), awn length (75.7%), number of spikelets per spike (42.8%) and number of seeds per spike (100% sterile) from Mir-grown plants were substantially less than the controls. Distribution of moisture and roots throughout the substrate was very good. All florets on Mir-grown spikes ceased development at the same stage of ontogeny. Lack of caryopses formation was attributed to male sterility occurring at different stages of staminal development. Anthers failed to dehisce and pollen grains were smaller and shriveled compared to the controls, suggesting a chronic stress had occurred in the Svet growth chamber. Recent ground-based studies indicated that ethylene, which was measured at 0.3 to 1.8 mg kg-1 in the Mir, almost certainly could have induced male sterility in the wheat plants grown on the Mir.

Six-month space greenhouse experiments--a step to creation of future biological life support systems.

SVET Space Greenhouse (SG)--the first automated facility for growing of higher plants in microgravity was designed in the eighty years to be used for the future BLSS. The first successful experiment with vegetables was carried out in 1990 on the MIR Space Station (SS). The experiments in SVET SG were resumed in 1995, when an American Gas Exchange Measurement System (GEMS) was added. A three-month wheat experiment was carried out as part of MIR-SHUTTLE'95 program. SVET-2 SG Bulgarian equipment of a new generation with optimised characteristics was developed (financed by NASA). The new SVET-GEMS equipment was launched on board the MIR SS and a successful six-month experiments for growing up of two crops of wheat were conducted in 1996 - 97 as part of MIR-NASA-3 program. The first of these "Greenhouse" experiments (123 days) with the goal to grow wheat through a complete life cycle is described. Nearly 300 heads developed but no seeds were produced. A second crop of wheat was planted and after 42 days the plants were frozen for biochemical investigations. The main environmental parameters during the six-month experiments in SVET (substrate moisture and lighting period) are given. The results and the contribution to BLSS are discussed.

Launch conditions might affect the formation of blood vessels in the quail chorioallantoic membrane.

As a part of the first joint USA-Russian MIR/Shuttle program, fertilized quail eggs were flown on the MIR 18 mission. Post-flight examination indicated impaired survival of both the embryos in space and also of control embryo exposed to vibrational and g-forces simulating the condition experienced during the launch of Progress 227. We hypothesized that excess mechanical forces and/or other conditions during the launch might cause abnormal development or the blood supply in the chorioallantoic membrane (CAM) leading to the impaired survival of the embryos. The CAM, a highly vascularized extraembryonic organ, provides for the oxygen exchange across the egg shell and is thus pivotal for proper embryonic development. To test our hypothesis, we compared angiogenesis in CAMs of eggs which were either exposed to the vibration and g-force profile simulating the conditions at launch of Progress 227 (synchronous controls), or kept under routine conditions in a laboratory incubator (laboratory controls). At various time points during incubation, the eggs were fixed in paraformaldehyde for subsequent dissection. At the time of dissection, the CAM was carefully lifted from the egg shell and examined as whole mounts by bright-field and fluorescent microscopy. The development of the vasculature (angiogenesis) was assessed from the density of blood vessels per viewing field and evaluated by computer aided image analysis. We observed a significant decrease in blood-vessel density in the synchronous controls versus "normal" laboratory controls beginning from day 10 of incubation. The decrease in vascular density was restricted to the smallest vessels only, suggesting that conditions during the launch and/or during the subsequent incubation of the eggs may affect the normal progress of angiogenesis in the CAM. Abnormal angiogensis in the CAM might contribute to the impaired survival of the embryos observed in synchronous controls as well as in space.

Dissociation between beta-2 microglobulin and IL-1 production in hemodialyzed patients.

BACKGROUND: beta-2 microglobulin is predominant in amyloid deposits in patients undergoing long term hemodialysis. Amyloid accumulation has been ascribed to dialysis membranes, endotoxin contamination of the dialysate, uremia and chronic systemic inflammation associated with enhanced monocytic cytokine production in hemodialyzed patients. Interleukin-1 has been proposed to play a critical role in the induction of beta-2 microglobulin synthesis and release. METHODS: We examined if monocytes contribute to beta-2 microglobulin production upon stimulation with inflammatory mediators that are generated during hemodialysis and investigated the production of beta-2 microglobulin by cells from patients, with and without clinical signs of amyloidosis, at the time when patients' monocytes contained maximal intracellular accumulation of IL-1. RESULTS: We demonstrated that only monocytes are able to release increased levels of beta-2 microglobulin upon stimulation by IL-1, TNF alpha, C5a and LPS. Increased levels of beta-2 microglobulin were associated with increased levels of beta-2 microglobulin mRNA. Before dialysis session, 20-60% of circulating CD14+ monocytes from patients contained IL-1. At the time when maximal IL-1 production was detected, we showed by RT-PCR increased transcription of IL-1 gene in patients' monocytes. We observed that monocytes from patients with amyloidosis contained higher amounts of IL-1 as compared to monocytes from patients without clinical signs of amyloidosis, but could not secrete increased amounts of beta-2 microglobulin upon LPS-stimulation. CONCLUSIONS: Our data indicated that chronic inflammation, as demonstrated by increased intracellular IL-1 expression, is not associated with increased production of beta-2 microglobulin by monocytes from patients on hemodialysis.

Growing super-dwarf wheat in Svet on Mir.

In cooperation with Russian colleagues, we will carry out three experiments with a super-dwarf cultivar of wheat in the plant growth chamber Svet on the Russian Space Station Mir: an early test of the root module and other instruments (July-August, 1995), a seed-to-seed experiment (1996), and a third planting that will be harvested after about 35 days, frozen, and returned to Earth for chemical analysis (1996). Plants will be photographed, sampled,and chemically fixed at intervals during the first two plantings. Instrumentation has been constructed to measure CO2, water vapor, air temperatures, infrared leaf temperatures, oxygen, pressure, irradiance levels, and moisture in the root module substrate (Balkanine). The primary objective of this equipment is to allow controllers to eliminate plant environmental stresses, leading to vigorous plant growth in microgravity. We are testing sampling and analysis techniques and growing plants in ground versions of Svet in Moscow and in Svet mockups in Utah: 12 chambers in two temperature-controlled rooms, with two compartments in each chamber (two temperatures, four CO2 concentrations, and three photoperiods in a current experiment).

Seedling growth and development on space shuttle.

Young pine seedlings, and mung bean and oat seeds were flown on shuttle flights, STS-3 and STS-51F, in March, 1982 and July/August, 1985, respectively. The plant growth units built to support the two experiments functioned mechanically as anticipated and provided the necessary support data. Pine seedlings exposed to the microgravity environment of the space shuttle for 8 days continued to grow at a rate similar to ground controls. Pine stems in flight seedlings, however, averaged 10 to 12% less lignin than controls. Flight mung beans grew slower than control beans and their stems contained about 25% less lignin than control seedlings. Reduced mung bean growth in microgravity was partly due to slower germination rate. Lignin also was reduced in flight oats as compared to controls. Oats and mung beans exhibited upward growing roots which were not observed in control seedlings. Chlorophyll A/B ratios were lower in flight tissues than controls. The sealed PGCs exhibited large variations in atmospheric gas composition but the changes were similar between flight and ground controls. Ethylene was present in low concentrations in all chambers.

Norepinephrine content in discrete brain areas and neurohypophysial vasopressin in rats after a 9-d spaceflight (SLS-1).

The norepinephrine (NE) content in discrete brain areas and the vasopressin content in the neurohypophysial system were assessed in rats after a 9-d spaceflight and after a recovery period (9 d). The NE content in the locus coeruleus decreased significantly in spaceflight rats (2.9 +/- 0.3 vs. 8.9 +/- 0.7 pmol.structure-1 for control rats, p < 0.001), but showed no difference between control and flight animals after a 9-d recovery. These findings were probably due to an acute stress undergone during landing. The NE content was unchanged in the A2 and A5 cell groups. In rats flown aboard SLS-1, the vasopressin content was increased in the posterior pituitary (1.47 +/- 0.1 vs. 0.86 +/- 0.1 micrograms.structure-1, for control rats, p < 0.01), and was significantly decreased in the hypothalamus (8.95 +/- 2.0 vs. 17.6 +/- 2.2 ng.structure-1, for control rats, p < 0.05). We conclude that the NE depletion in the locus coeruleus and the alteration in vasopressin release were consistent with an acute stress, likely occurring during and/or after landing. These changes tend to mask the actual neuroendocrine modifications caused by microgravity.

Complement activation and cytokine production as consequences of immunological bioincompatibility of extracorporeal circuits.

The use of devices which result in exposure of blood to artificial surface has gained increasing importance in routine medical and surgical practice. In the field of biocompatibility, attention has long been directed at the mechanisms of thrombus formation of surfaces. In recent years however, a special interest has emerged for the study of the immunological consequences of blood-artificial surface interactions, thus broadening the concept of hemocompatibility. The contact of blood with artificial devices results in the activation of a number of humoral and cellular processes involved in natural and in specific immunological recognition of foreign surfaces by the host, and in the secondary occurrence of acute and chronic adverse reactions in patients undergoing extracorporeal circulation. The purpose of this review is to discuss the mechanisms involved in immunological bioincompatibility of extracorporeal circuits, with particular emphasis on the molecular basis of the activation of the complement system, the role of endotoxins, and the induction of cytokine production by activated monocytes.

Membrane molecules which trigger the production of interleukin-1 and tumor necrosis factor-alpha by lipopolysaccharide-stimulated human monocytes.

We have investigated the role of the membrane molecules CD11/CD18 and CD14 which may mediate the binding of lipopolysaccharide (LPS) to human monocytes, in the induction of the production and release of interleukin (IL)-1 and tumor necrosis factor-alpha (TNF-alpha) by LPS-stimulated cells. Blockade of CD11a, CD11b and CD18 with saturating concentrations of specific mAb did not inhibit the release of cytokines from LPS-stimulated monocytes. In contrast, inhibition of the release of IL-1 beta and TNF-alpha occurred in monocytes cultures that had been pretreated with either of two monoclonal antibodies (mAb) recognizing different epitopes on the CD14 molecule. The binding of LPS to CD14 has been previously shown to require serum factors. In the present study, we found that serum had an enhancing effect on the release of IL-1 and TNF-alpha from LPS-stimulated cultures of normal human monocytes. The inhibitory effect of anti-CD14 mAb was, however, observed in cultures performed in the presence or in the absence of serum, suggesting that triggering of IL-1/TNF-alpha release by CD14 is independent of LPS-binding proteins or other serum proteins. IL-1 beta and TNF-alpha were also released from LPS-stimulated cultures of monocytes from patients with paroxysmal nocturnal hemoglobinuria lacking expression of CD14. Thus, CD14 but not CD11/CD18 can trigger serum-dependent and independent cytokine release from endotoxin-stimulated normal human monocytes; CD14 is not, however, the only LPS receptor that is involved in the secretory response of endotoxin-stimulated cells.

Coenzyme Q in serum and muscle of 5 patients with Kearns-Sayre syndrome and 12 patients with ophthalmoplegia plus.

Coenzyme Q10 (CoQ) was measured in serum and muscle of 17 patients with ophthalmoplegia plus (including 5 patients with Kearns-Sayre syndrome), in muscle of 9 patients with neurogenic atrophies, 5 patients with myositis, and 5 patients with progressive muscular dystrophies (including 1 patient with oculopharyngeal dystrophy), and in serum and muscle of normal controls. CoQ was markedly decreased in serum and muscle of 1 patient with Kearns-Sayre syndrome and treatment with CoQ resulted in a significant clinical improvement. The other 4 patients with Kearns-Sayre syndrome and the patients with ophthalmoplegia plus exhibited normal concentrations of CoQ in serum and muscle. CoQ levels in muscle of patients with progressive muscular dystrophies, myositis or neurogenic atrophies were within the normal range. Concentrations of CoQ in serum and muscle of normal controls were independent of age and showed no sex difference. The data indicate that CoQ deficiency might be the specific cause of mitochondrial encephalomyopathy in 1 patient but it was not the underlying defect common to all cases with Kearns-Sayre syndrome and ophthalmoplegia plus, although the possibility of a focal CoQ deficiency affecting only single muscle fibres cannot be excluded.

Spontaneous variability of simple and complex ventricular premature contractions during long time intervals in patients with severe organic heart disease.

Calculations of the spontaneous variability of ventricular arrhythmias are usually based upon the results of Holter electrocardiograms recorded either successively or separated by a short time interval. Only recently was it shown that the variability of ventricular premature contractions increases with longer intervals. This study was undertaken to investigate the variability of simple and complex ventricular arrhythmias over long periods to derive efficacy criteria for long-term antiarrhythmic therapy. In a prospective study, the influence of the length of the time interval on spontaneous variability was investigated in 100 patients with coronary artery disease or idiopathic dilated cardiomyopathy and untreated ventricular arrhythmia Lown grade IV. Patient follow-up was carried out for 260 +/- 387 days. In each of the 498 ambulatory Holter tapes, the mean hourly arrhythmia count (AC) of ventricular premature contractions, couplets, and salvos was verified. The variability of arrhythmia counts between two Holter electrocardiograms was defined as the logarithm of the ratio of (ACday 2 + 0.01) to (ACday 1 + 0.01). The 95% intervals for these ratios were calculated as +/- 2 SD, considering the fact that all mean values did not differ significantly from zero. The lower limit of these intervals refers to the reduction that is required for assuming drug efficacy, whereas the upper limit refers to an aggravation. The 95% intervals were calculated for each of four ranges of control intervals (0-6, 7-89, 90-364, and greater than or equal to 365 days). They increased significantly with longer control intervals.(ABSTRACT TRUNCATED AT 250 WORDS)

[Spontaneous variability of complex ventricular extrasystoles over a period of up to 4 years]. / Spontanvariabilität komplexer ventrikulärer Extrasystolen über einen Zeitraum bis zu 4 Jahren.

In a prospective study, the influence of the length of the time interval on spontaneous variability was investigated in 100 patients with CAD or IDC and untreated ventricular arrhythmia of Lown grade IV. Patient follow-up was carried out over 260 +/- 387 days. In each of the 498 ambulatory Holter tapes, the mean hourly arrhythmia count (AC) of couplets and salvos was verified. The variability of ACs between two Holter ECGs was defined as the logarithm of the quotient AC day 2(n + 0.01)/AC day 1(n + 0.01). The spontaneous distribution of variability quotients (means +/- 2 SD) was defined separately for couplets and salvos and for each of four ranges of control intervals (0-6 days, 7-89 days, 90-364 days, greater than or equal to 365 days). The percentage change in arrhythmia count necessary to establish drug efficacy (R), was calculated according to the formula R(%) = (10(0) - 10(-2SD].100, whereas the percentage change necessary to prove aggravation of arrhythmia (A) was assessed by the formula A(%) = (10(0) + 10(+2SD].100. For couplets, R extended from 90%, 94%, 98% to 99%; A increased from 1114%, 1895%, 6153% to 14032%, respectively. For salvos, R remained almost unchanged at a high level with 95%, 98%, 98%, 99%. The figures of A were 2189%, 4650%, 5698% and 9650%, respectively. It is concluded that the spontaneous variability of complex ventricular arrhythmias is remarkably high with short control intervals and increases further with longer ones.(ABSTRACT TRUNCATED AT 250 WORDS)

Microgravity effects on plant growth and lignification.

Lignin is a major cellular component of higher plants. One function of lignin is to support vertical plant growth in a gravity environment. Various investigators working in the 1 g environment have concluded that lignification is influenced by gravity. An experiment was designed for flight on Spacelab II to determine the effect of microgravity on lignification in young plant seedlings. A secondary objective of the experiment was to examine the effect of microgravity on overall seedling growth. Mung bean and oat seeds germinated and the seedlings grew under the Spacelab II mission. Growth of flight mung bean and oat seedlings, however, was slower, and the seedlings exhibited stem and root orientation difficulties. Flight pine seedlings were similar in appearance and growth to 1 g controls. The rate of lignin formation in seedlings grown in space was significantly less in all three species in comparison to 1 g controls. The experiment provided direct evidence that lignification is slowed in a microgravity environment.

[Spontaneous variability of ventricular extrasystoles: criteria for validating anti-arrhythmia therapy in relation to the length of the control interval]. / Spontanvariabilität ventrikulärer Extrasystolen: Kriterien zur Validierung einer antiarrhythmischen Therapie in Abhängigkeit von der Länge des Kontrollintervalls.

Calculations about the variability of PVCs are usually based upon the results of two Holter ECGs, either successive ones or separated by a short interval. No studies are available indicating whether the criteria calculated for short control intervals also holds true when evaluating chronic antiarrhythmic treatment over longer control periods. This study was performed to investigate the influence of the length of the control interval on the spontaneous variability and thus on the reduction of PVCs required to secure an antiarrhythmic effect. In a prospective study, 444 ambulatory ECGs were obtained in 90 patients with CAD or IDC and untreated ventricular arrhythmia of Lown grade IV. Patient follow-up was carried out over an average of 181 +/- 297 days. The degree of arrhythmia was expressed as the mean hourly PVC rate. The variability of PVC counts between two Holter ECGs was defined as the logarithm of the quotient PVCday 2(n + 1)/PVCday 1(n + 1). The spontaneous distribution of variability quotients was defined separately (mean +/- 2 SD) for each of four ranges of control intervals (0-6 days, 7-89 days, 90-364 days, greater than or equal to 365 days). The per cent reduction (R) in PVC frequency necessary to establish drug efficacy, was calculated according to the formula R (%) = 10(0)-10(-2SD) X 100, whereas the percentage change necessary to prove aggravation of arrhythmia (A) was assessed by the formula A (%) = 10(0)+10(+2SD X 100. R increased from 63% (0-6 days), 81% (7-89 days), 93% (90-364 days) to 98% (greater than or equal to 365 days).(ABSTRACT TRUNCATED AT 250 WORDS)

[Analysis of the accuracy of the Holter system ICR 6201-G3]. / Analysegenauigkeit des Holter-Systems ICR 6201-G3.

UNLABELLED: The accuracy of the Holter System ICR 6201-G3 was investigated by evaluation of 32 Holter recordings taken randomly from the hospital's ECG laboratory. All events were classified into true positive, false positive and false negative diagnoses. Sensitivity (S) and predictive accuracy (PA) were calculated. RESULTS: QRS complexes: S 99.9%, PA 99.9%; supraventricular premature beats: S 98.3%, PA 81.1%; single ventricular premature beats: S 96.8%, PA 97.4%; ventricular couplets: S 96.4%, PA 95.6%; ventricular salvos: S 98.6%, PA 90.8%; pauses: S 100%, PA 91.7%. It is concluded that despite a relatively good overall accuracy of automatic arrhythmia detection, on account of the lower accuracy in the evaluation of all clinically important arrhythmias and of the markedly worse accuracy in some instances, a fully automatic use of the system cannot be recommended. Repetitive ventricular arrhythmias and asystolies must be controlled by hand.