Enhanced expression of heat shock proteins in leukocytes from trauma patients

BACKGROUND

Heat shock proteins (HSPs) play essential roles as molecular chaperones in cells to assist in the repair of degenerated proteins. The expression of HSPs in polymorphonuclear leukocytes (PMNLs) following insult has not been delineated. The objective of this study was to clarify the serial changes in HSP expression in PMNLs from trauma patients.

METHODS

Fifty severely injured patients (mean Injury Severity Score of 31.8 +/- 10.8) and 17 healthy volunteers were included as study subjects. Blood samples were serially obtained at three time points: days 0 to 1, days 2 to 5, and days 6 to 14 after the trauma event. We measured expressions of HSP27, HSP60, HSP70, and HSP90 in permeabilized PMNLs by flow cytometry using a monoclonal antibody generated against each HSP and fluorescein isothiocyanate-conjugated antimouse immunoglobulins as secondary reagents. We also evaluated the expression of HSP70 mRNA in PMNLs by Northern blot hybridization and the expression of HSP70 in PMNLs by fluorescence microscopy.

RESULTS

Expressions of HSP27, HSP70, and HSP90 in PMNLs from trauma patients were significantly greater than in PMNLs from healthy volunteers in all three periods (days 0-1, days 2-5, and days 6-14). The expression of HSP60 in PMNLs from trauma patients was significantly greater than normal expression on days 2 to 5 and days 6 to 14. The values for HSP27, HSP60, and HSP70 on days 2 to 5 were significantly higher than those on days 0 to 1. The expression of HSP70 mRNA in PMNLs was significantly enhanced for as long as 2 weeks after trauma compared with that in normal volunteers.

CONCLUSION

Severe trauma causes demonstrated enhanced expression of HSPs in PMNLs during the acute phase. This enhanced expression of HSPs may regulate PMNL functions.

Growth and development in higher plants under simulated microgravity conditions on a 3-dimensional clinostat

Growth and development of etiolated pea (Pisum sativum L. cv. Alaska) and maize (Zea mays L. cv. Golden Cross Bantam) seedlings grown under simulated microgravity conditions were intensively studied using a 3-dimensional clinostat as a simulator of weightlessness. Epicotyls of etiolated pea seedlings grown on the clinostat were the most oriented toward the direction far from cotyledons. Mesocotyls of etiolated maize seedlings grew at random and coleoptiles curved slightly during clinostat rotation. Clinostat rotation promoted the emergence of the 3rd internodes in etiolated pea seedlings, while it significantly inhibited the growth of the 1st internodes. In maize seedlings, the growth of coleoptiles was little affected by clinostat rotation, but that of mesocotyls was suppressed, and therefore, the emergence of the leaf out of coleoptile was promoted. Clinostat rotation reduced the osmotic concentration in the 1st internodes of pea seedlings, although it has little effect on the 2nd and the 3rd internodes. Clinostat rotation also reduced the osmotic concentrations in both coleoptiles and mesocotyls of maize seedlings. Cell-wall extensibilities of the 1st and the 3rd internodes of pea seedlings grown on the clinostat were significantly lower and higher as compared with those on 1 g conditions, respectively. Cell-wall extensibility of mesocotyls in seedlings grown on the clinostat also decreased. Changes in cell wall properties seem to be well correlated to the growth of each organ in pea and maize seedlings. These results suggest that the growth and development of plants is controlled under gravity on earth, and that the growth responses of higher plants to microgravity conditions are regulated by both cell-wall mechanical properties and osmotic properties of stem cells.

Characteristics of infection and leukocyte count in severely head-injured patients treated with mild hypothermia

OBJECTIVE

This study was designed to characterize the infectious complications and kinetics of leukocyte count in severely head-injured patients treated with mild hypothermia.

PATIENTS AND METHODS

We retrospectively analyzed the incidence and severity of infectious complications as well as daily changes in leukocyte count in 41 severely head-injured patients treated with mild hypothermia (group H). They were retrospectively compared with 25 severely head-injured patients treated with high-dose barbiturates (group B) and to 25 other severely head-injured patients treated with no barbiturates (group N).

RESULTS

Initial intracranial pressure was significantly higher in group H than in the other groups. No significant differences existed in the incidence of pneumonia or meningitis among the three groups, whereas the incidence of bacteremia was significantly higher in group H than in the other two groups. Pneumonia was significantly more severe in group H than in the other groups. In six patients of group H, pneumonia spread fulminantly to become life threatening. Daily changes in total leukocyte count showed the same pattern, consisting of a peak, a nadir, and a second peak in all groups. Total leukocyte count was, however, significantly lower during the first 2 weeks in group H than in the other two groups. Lymphocyte and neutrophil counts were also lower in group H.

CONCLUSION

Infectious complications were more severe and leukocyte counts were lower in patients treated with mild hypothermia, who also had the highest initial intracranial pressures, than in patients treated with conventional therapies. Measures against increased susceptibility to infection and leukocyte suppression should be explored.

Control of gravimorphogenesis by auxin: accumulation pattern of CS-IAA1 mRNA in cucumber seedlings grown in space and on the ground

Cucumber (Cucumis sativus L.) seedlings grown in microgravity developed a peg on each side of the transition zone between hypocotyl and root, whereas seedlings grown in a horizontal position on the ground developed a peg on the concave side of the gravitropically bending transition zone. The morphological features of the space-grown seedlings were similar to those of seedlings grown in a vertical position on the ground with their radicles pointing down: both became two-pegged seedlings. Morphogenesis of cucumber seedlings is thus inhibited by gravity. Analysis by in-situ hybridization of an auxin-inducible gene, CS-IAA1, showed that its mRNA accumulated to a much greater extent on the lower side of the transition zone in the horizontally placed seedlings on the ground just prior to and during the initiation period of peg formation. On the other hand, when seedlings were grown in microgravity or in a vertical position on the ground, accumulation of CS-IAA1 mRNA occurred all around the transition zone. Accumulation of CS-IAA1 mRNA in horizontally grown seedlings appreciably decreased on the upper side of the transition zone and increased on the lower side upon gravistimulation, compared with the two-pegged seedlings. Application of IAA to seedlings in a horizontal position caused the development of a peg on each side of the transition zone, or a collar-like protuberance, depending on the concentration used. These results suggest that upon gravistimulation the auxin concentration on the upper side of the horizontally placed transition zone is reduced to a level below the threshold value necessary for peg formation. Space-grown seedlings of cucumber might develop two pegs symmetrically because the auxin level in the entire transition zone is maintained above the threshold. This spaceflight experiment verified for the first time that auxin does not redistribute in microgravity.

Changes in contused lung volume and oxygenation in patients with pulmonary parenchymal injury after blunt chest trauma

Although it is well known that pulmonary parenchymal injury impairs oxygenation, the relationship between hypoxemia and volume of the contused lung after blunt chest trauma remains unknown. We studied 23 blunt chest trauma patients who underwent thoracic computed tomography (CT) within 24 hours after admission and also underwent follow-up CT at 1-week intervals until abnormal lung findings disappeared. Contused lung volume was determined quantitatively by CT. CT findings of parenchymal injury were either a diffuse lesion that disappeared within 1 week (n = 9 patients, group 1), or a solitary lesion that remained a few weeks after resolution of the diffuse lesion (n = 14 patients, group 2). PaO2/FiO2 was positively correlated with the volume of contused lung during the first 24 hours in both groups, however, there was no significant correlation after 1 week after injury. Degree of impaired oxygenation is related to the volume of the diffuse lesion that is recognized soon after injury.

Effect of growth hormone on brain oedema caused by a cryogenic brain injury model in rats

Although growth hormone (GH) is a potential agent to counteract the catabolic response to general and head injuries, the complications of GH treatment have been little studied. To evaluate the safety of GH in head trauma patients, it was investigated whether GH affects brain oedema caused by brain injury, using a rat freeze-injury model. Male Wistar rats (n = 28) were divided into four groups according to the substance injected (GH vs. saline) and whether brain was injured or not. GH (0.8 IU/kg) or saline was injected subcutaneously every 24 hours. In the injury groups, immediately before the first injection of GH, an aluminum rod cooled to -50 degrees C was placed on the right parietal region for 4 minutes, under anaesthesia. At 96 hours after the insult, brain and skeletal muscle were excised and their water content was measured, by drying. Freeze injury of the brain caused an increase in water content in skeletal muscle. GH injection augmented this oedema in skeletal muscle. Freeze injury of the brain also caused an increase in water content in the injured and non-injured hemispheres of brain and cerebellum. GH administration did not exacerbate brain oedema caused by brain injury in this model.

Half-life of blood carboxyhemoglobin after short-term and long-term exposure to carbon monoxide

BACKGROUND

In models of smoke inhalation injury and carbon monoxide poisoning blood carboxy-hemoglobin (COHb) levels decrease faster than predicted by the generally recognized half-life of COHb. We studied the effects of duration of exposure to carbon monoxide (CO) on the subsequent CO elimination.

METHODS

Each of four sheep were insufflated with CO gas mixtures either for a few minutes (short-term exposure) or for several hours (long-term exposure), then ventilated with air for 3 hours. Serial COHb concentrations were analyzed by using a two-compartment, single central outlet mathematical model.

RESULTS

Short-term exposures exhibited biphasic decreases of COHb concentration compatible with a two-compartment model; an initial rapid decrease (half-life 5.7 +/- 1.4 minutes) was followed by a slower phase (103 +/- 20.5 minutes). Long-term exposures exhibited almost monophasic decreases, which were nevertheless compatible with the model (half-life, 21.5 +/- 2.1 and 118 +/- 11.2 minutes).

CONCLUSION

This study demonstrated different patterns of CO elimination curve, which suggests distribution of CO to two compartments having different rates of equilibration.

Does blood type B protect against haemolytic uraemic syndrome? An analysis of the 1996 Sakai outbreak of Escherichia coli O157:H7 (VTEC O157) infection. The Osaka HUS Critical Care Study Group

OBJECTIVES

Expression of the P1 blood type antigen is suggested to have a protective effect against post-enteropathic haemolytic uraemic syndrome (HUS). The B blood type may also protect against HUS, since terminal trisaccharide sequences similar to those of the B blood type determinants are reported to have an affinity to Vero cytotoxin that is 23% as strong as that of the P1 determinants. Thus, we studied whether ABO blood types were related to the occurrence or severity of HUS.

METHODS

We obtained clinical and laboratory data of 49 HUS patients treated in 14 critical care facilities during the 1996 Escherichia coli O157:H7 outbreak in Sakai, Japan. We retrospectively studied whether ABO blood types were related to the occurrence or severity of HUS.

RESULTS

The numbers of patients with blood types A, B, O or AB were 29, 8, 12, and 0, respectively. For each blood type, the number of patients with severe renal complications was 16, 6, 9, and 0, respectively. The distribution of blood types among the HUS patients deviated from a population-based distribution of blood types (P<0.05, Chi-squared test); i.e., the frequency of the A blood phenotype was significantly higher among our HUS patients. However, there was no significant difference in the frequency of patients with the A antigen (A and AB blood groups) among our HUS patients, whereas the frequency of B antigen expression was significantly lower (P<0.05, Chi-squared test). The risk of severe renal complications did not appear to be related to ABO blood types.

CONCLUSIONS

Our data suggest that expression of the B antigen has a protective effect against the onset of HUS, but that it does not affect the severity of the disease.

Growth regulation mechanisms in higher plants under microgravity conditions - changes in cell wall metabolism

During Space Shuttle STS-95 mission, we cultivated seedlings of rice (Oryza sativa L. cv. Koshihikari and cv. Tan-ginbozu) and Arabidopsis (Arabidopsis thaliana L. cv. Columbia and cv. etr1-1) for 68.5, 91.5, and 136 hr on board, and then analyzed changes in the nature of their cell walls, growth, and morphogenesis under microgravity conditions. In space, elongation growth of both rice coleoptiles and Arabidopsis hypocotyls was stimulated. Also, the increase in the cell wall extensibility, especially that in the irreversible extensibility, was observed for such materials. The analyses of the amounts, the structure, and the physicochemical properties of the cell wall constituents indicated that the decreases in levels and molecular masses of cell wall polysaccharides were induced under microgravity conditions, which appeared to contribute to the increase in the wall extensibility. The activity of certain wall enzymes responsible for the metabolic turnover of the wall polysaccharides was increased in space. By the space flight, we also confirmed the occurrence of automorphogenesis of both seedlings under microgravity conditions; rice coleoptiles showed an adaxial bending, whereas Arabidopsis hypocotyls elongated in random directions. Furthermore, it was shown that spontaneous curvatures of rice coleoptiles in space were brought about uneven modifications of cell wall properties between the convex and the concave sides.

Inhibition of root elongation in microgravity by an applied electric field

Roots grown in an applied electric field demonstrate a bidirectional curvature. To further understand the nature of this response and its implications for the regulation of differential growth, we applied an electric field to roots growing in microgravity. We found that growth rates of roots in microgravity were higher than growth rates of ground controls. Immediately upon application of the electric field, root elongation was inhibited. We interpret this result as an indication that, in the absence of a gravity stimulus, the sensitivity of the root to an applied electric stimulus is increased. Further space experiments are required to determine the extent to which this sensitivity is shifted. The implications of this result are discussed in relation to gravitropic signaling and the regulation of differential cell elongation in the root.

STS-95 space experiment for plant growth and development, and auxin polar transport

The principal objective of the space experiment, BRIC-AUX on STS-95, was the integrated analysis of the growth and development of etiolated pea and maize seedlings in space, and the effect of microgravity conditions in space on auxin polar transport in the segments. Microgravity conditions in space strongly affected the growth and development of etiolated pea and maize seedlings. Etiolated pea and maize seedlings were leaned and curved during space flight, respectively. Finally the growth inhibition of these seedlings was also observed. Roots of some pea seedlings grew toward the aerial space of Plant Growth Chamber. Extensibilities of cell walls of the third internode of etiolated pea epicotyls and the top region of etiolated maize coleoptiles which were germinated and grown under microgravity conditions in space were significantly low. Activities of auxin polar transport in the second internode segments of etiolated pea seedlings and coleoptile segments of etiolated maize seedlings were significantly inhibited and extremely promoted, respectively, under microgravity conditions in space. These results strongly suggest that auxin polar transport as well as the growth and development of plants is controlled under gravity on the earth.

Gravimorphogenesis of Cucurbitaceae plants: development of peg cells and graviperception mechanism in cucumber seedlings

We examined the effect of microgravity on the peg formation of cucumber seedlings for clarifying the mechanism of gravimorphogenesis in cucurbitaceous plants. The spaceflight experiments verified that gravity controls the formation of peg, hypocotyl hook and growth orientation of cucumber seedlings. Space-grown cucumber developed a peg on each side of the transition zone of the hypocotyl and root, indicating that on the ground peg formation is regulated negatively by gravity (Takahashi et al. 2000). It was found that the auxin-regulated gene, CS-IAA1, was strongly expressed in the transition zone where peg develops (Fujii et al. 2000). In the seedlings grown horizontally on the ground, CS-IAA1 transcripts were much abundant on the lower side of the transition zone, but no such differential expression of CS-IAA1 was observed in the space-grown cucumber (Kamada et al. 2000). These results imply that gravity plays a role in peg formation through auxin redistribution. By the negative control, peg formation on the upper side of the transition zone in the horizontally growing seedlings might be suppressed due to a reduction in auxin concentration. The threshold theory of auxin concentration accounted for the new concept, negative control of morphogenesis by gravity (Kamada et al. 2000). Anatomical studies have shown that there exists the target cells destined to be a peg and distinguishable at the early stage of the growth. Ultra-structural analysis suggested that endoplasmic reticulum develops well in the cells of the future peg. Furthermore, it was found that reorganization of cortical microtubules is required for the change in cell growth polarity in the process of peg formation. The spaceflight experiment with cucumber seedlings also suggested that in microgravity positive hydrotropic response of roots occurred without interference by gravitropic response (Takahashi et al. 1999b). Thus, this spaceflight experiment together with the ground-based studies has shown that cucumber seedling is an ideal for the study of gravimorphogenesis, hydrotropism and their interaction. Although peg formation is seen specifically in cucurbitaceous seedlings, it involves graviperception, auxin transport and redistribution and cytoskeletal modification for controlling cell growth polarity. This system could be a useful model for studying important current issues in plant biology.

Aggravation of chemically-induced injury in perfused rat liver by extracellular ATP

The effects of purinergic receptor agonists on acute liver damage and hemodynamics were studied using chemically-induced liver injury. Rat livers were perfused in situ 24 h after treatment with D-galactosamine (800 mg/kg, i.p.). In these livers, infusion of ATP (50 microM) into the portal vein caused a rapid increase in the leakage of LDH and AST from perfused liver in a dose dependent manner, accompanied with flow reduction. The similar but less effective responses were also observed by the infusion of ADP. Infusion of adenosine, a P1-receptor agonist, induced only minimal changes of liver damage and flow rate. The ATP-induced changes were almost completely suppressed by P2-receptor antagonist, suramin, but not affected by P1-receptor antagonist, 8-phenyltheophylline. Pretreatment of rats with gadolinium chloride, which depletes Kupffer cells, did not inhibit the potentiation of liver damage caused by ATP, whereas hemodynamic effects of ATP were significantly attenuated by gadolinium. These results indicate that extracellular ATP aggravates acute liver injury mediated by P2-type purinergic receptors.

Difference in the responses after administration of granulocyte colony-stimulating factor in septic patients with relative neutropenia

OBJECTIVE

The objective of this study was to classify the clinical responses after administration of granulocyte colony-stimulating factor (G-CSF) in septic patients with relative neutropenia.

PATIENTS AND METHODS

We administered recombinant human G-CSF (2 microg/kg) subcutaneously once a day for 5 days to 30 septic patients with white cell counts below 5,000 cells/mm3. Absolute neutrophil count (ANC), neutrophil differentiation, and serum concentration of G-CSF were determined serially. Bone marrow also was analyzed before and after treatment.

RESULTS

Neutrophil responses to G-CSF varied from good (ANC > 10,000/mm3, group G, n = 20) to moderate (ANC < 10,000/mm3, group M, n = 5) to poor (no increase in ANC, group P, n = 5). Before G-CSF administration, the three groups showed no differences in ANC but did show significant differences in serum concentration of G-CSF. G-CSF concentration was 0.16 +/- 0.03 ng/mL in group G, 7.0 +/- 3.0 ng/mL in group M, and 270 +/- 90 ng/mL in group P. Immature neutrophils accounted for 35.0 +/- 3.7% of peripheral leukocytes in group P but only 5.1 +/- 0.6% in group G. Although bone marrow was depressed in all groups before G-CSF treatment, nucleated cell count increased significantly after rhG-CSF treatment in groups G and M. Survival rate after 4 weeks was 90% in group G and 100% in group M; no patient in group P survived.

CONCLUSION

G-CSF administration was effective in septic patients with a low percentage of immature neutrophils and insufficient endogenous G-CSF. It had little effect on patients with a high percentage of immature neutrophils whose G-CSF production was up-regulated and whose bone marrow was severely depressed.

Suitable experimental design for determination of auxin polar transport in space using a spacecraft

It is necessary to establish a suitable experimental design for the determination of auxin (indole-3-acetic acid: IAA) polar transport in space using a spacecraft in concerning with the role of gravity. Problems in space experiments are as follows: I) Selection of suitable plant species; II) Preservation of integrity of plant segments for activities of auxin polar transport; III) Stop of auxin polar transport of the segments after the transport experiment in space. Segments of etiolated pea epicotyls and etiolated maize coleoptiles showed relatively high activities of auxin polar transport among dicotyledonous and monocotyledonous plants tested, respectively. The activities decreased dramatically when the segments were pre-stored at 25 degrees C only for 1 day. On the other hand, the storage at low temperature (5 degrees C) in the presence of antioxidants or chelating agents, especially EGTA, maintained relatively high activities of auxin polar transport in pea epicotyl segments. Low temperature (5 degrees C) substantially inhibited the activity of auxin polar transport. Based on the results in this study, a suitable experimental design for the space experiment of auxin polar transport using a spacecraft is also proposed.

Morphogenesis in cucumber seedlings is negatively controlled by gravity

Seedlings of most cucurbitaceous plants develop a peg (protuberance caused by cell outgrowth) on the transition zone between the hypocotyl and root. The peg is necessary for removing the seed coat after germination. In our spaceflight experiments on the STS-95 space shuttle, Discovery, we found that cucumber (Cucumis sativus L.) seedlings grown under microgravity conditions developed two pegs symmetrically at the transition zone. Thus, cucumber seedlings potentially develop two pegs and do not require gravity for peg formation itself, but on the ground the development of one peg is suppressed in response to gravity. This may be considered as negative control of morphogenesis by gravity.

A spaceflight experiment for the study of gravimorphogenesis and hydrotropism in cucumber seedlings

Seedlings of Cucurbitaceae plants form a protuberance, termed peg, on the transition zone between hypocotyl and root. Our spaceflight experiment verified that the lateral positioning of a peg in cucumber seedlings is modified by gravity. It has been suggested that auxin plays an important role in the gravity controlled positioning of a peg on the ground. Furthermore, cucumber seedlings grown in microgravity developed a number of the lateral roots that grew towards the water containing substrate in the culture vessel, whereas on the ground they oriented perpendicular to the primary root growing down. The response of the lateral roots in microgravity was successfully mimicked by clinorotation of cucumber seedlings on the three dimensional clinostat. However, this bending response of the lateral roots was observed only in an aeroponic culture of the seedlings but not in solid medium. We considered the response of the lateral roots in microgravity and on clinostat as positive hydrotropism that could easily be interfered by gravitropism on the ground. This system with cucumber seedlings is thus a useful model of spaceflight experiment for the study of the gravimorphogenesis, root hydrotropism and their interaction.

Growth and development in Arabidopsis thaliana through an entire life cycle under simulated microgravity conditions on a clinostat

The effects of simulated microgravity conditions produced by a horizontal clinostat on the entire life cycle of Arabidopsis thaliana ecotype Columbia and Landsberg erecta were studied. Horizontal clinorotation affected little germination of seeds, growth and development of rosette leaves and roots during early vegetative growth stage, and the onset of the bolting of inflorescence axis and flower formation in reproductive growth stage, although it suppressed elongation of inflorescence axes. The clinorotation substantially reduced the numbers of siliques and seeds in Landsberg erecta, and completely inhibited seed production in Columbia. Seeds produced in Landsberg erecta on the clinostat were capable of germinating and developing rosette leaves normally on the ground. On the other hand, growth of pin formed mutant (pin/pin) of Arabidopsis ecotype Enkheim, which has a unique structure of inflorescence axis with no flower and extremely low levels of auxin polar transport activity, was inhibited and the seedlings frequently died during vegetative stage on the clinostat. Seed formation and inflorescence growth of the seedlings with normal shape (pin/+ or +/+) were also suppressed on the clinostat. These results suggest that the growth and development of Arabidopsis, especially in reproductive growth stage, is suppressed under simulated microgravity conditions on a clinostat. To complete the life cycle probably seems to be quite difficult, although it is possible in some ecotypes.

Inhibition of root elongation in microgravity by an applied electric field

Roots grown in an applied electric field demonstrate a bidirectional curvature. To further understand the nature of this response and its implications for the regulation of differential growth, we applied an electric field to roots growing in microgravity. We found that growth rates of roots in microgravity were higher than growth rates of ground controls. Immediately upon application of the electric field, root elongation was inhibited. We interpret this result as an indication that, in the absence of a gravity stimulus, the sensitivity of the root to an applied electric stimulus is increased. Further space experiments are required to determine the extent to which this sensitivity is shifted. The implications of this result are discussed in relation to gravitropic signaling and the regulation of differential cell elongation in the root.

Growth and development, and auxin polar transport in higher plants under microgravity conditions in space: BRIC-AUX on STS-95 space experiment

The principal objectives of the space experiment, BRIC-AUX on STS 95, were the integrated analysis of the growth and development of etiolated pea and maize seedlings in space and a study of the effects of microgravity conditions in space on auxin polar transport in these segments. Microgravity significantly affected the growth and development of etiolated pea and maize seedlings. Epicotyls of etiolated pea seedlings were the most oriented toward about 40 to 60 degrees from the vertical. Mesocotyls of etiolated maize seedlings were curved at random during space flight but coleoptiles were almost straight. Finally the growth inhibition of these seedlings in space was also observed. Roots of some pea seedlings grew toward to the aerial space of Plant Growth Chamber. Extensibilities of cell walls of the third internode of etiolated pea epicotyls and the top region of etiolated maize coleoptiles, which were germinated and grown under microgravity conditions in space, were significantly low as compared with those grown on the ground of the earth. Activities of auxin polar transport in the second internode segments of etiolated pea seedlings and coleoptile segments of etiolated maize seedlings were significantly inhibited and promoted, respectively, under microgravity conditions in space. These results strongly suggest that auxin polar transport as well as the growth and development of plants is controlled under gravity on the earth.

Morphogenesis of rice and Arabidopsis seedlings in space

Seedlings of rice (Oryza saliva L.) and Arabidopsis (A. thaliana L.) were cultivated for 68.5 hr in the RICE experiment on board during Space Shuttle STS 95 mission, and changes in their growth and morphology were analyzed. Microgravity in space stimulated elongation growth of both rice coleoptiles and Arabidopsis hypocotyls by making their cell walls extensible. In space, rice coleoptiles showed an inclination toward the caryopsis in the basal region and also a spontaneous curvature in the same direction in the elongating region. These inclinations and curvatures were more prominent in the Koshihikari cultivar compared to a dwarf cultivar, Tan-ginbozu. Rice roots elongated in various directions including into the air on orbit, but two thirds of the roots formed a constant angle with the axis of the caryopsis. In space, Arabidopsis hypocotyls also elongated in a variety of directions and about 10% of the hypocotyls grew into the agar medium. No clear curvatures were observed in the elongating region of Arabidopsis hypocotyls. Such a morphology of both types of seedlings was fundamentally similar to that observed on a 3 D clinostat. Thus, it was confirmed by the RICE experiment that rice and Arabidopsis seedlings perform an automorphogenesis under not only simulated but also true microgravity conditions.

Changes in left ventricular performance in patients with severe head injury during and after mild hypothermia

OBJECTIVE

To evaluate left ventricular (LV) performance in patients with severe head injury during and after mild hypothermia.

PATIENTS AND METHODS

Seven consecutive patients who underwent therapeutic mild hypothermia (age, 15 to 70 years; Glasgow Coma Scale score on admission, 4 to 8). LV performance was assessed by using M-mode, color tissue Doppler imaging tracings and pulsed Doppler echocardiography. LV contraction and relaxation were evaluated by using the peak velocity of LV posterior wall movement during systole (Smax) and diastole (Dmax), respectively, in addition to the conventional echocardiographic indices.

RESULTS

Mild hypothermia increased LV ejection time and reciprocally reduced LV filling period as indicated by temperature-dependent shortening of the early diastolic filling and the total diastolic inflow time. The indices depending on temporal factors such as ejection time, Smax, or Dmax were significantly affected by mild hypothermia, whereas those depending on spatial factors such as fractional shortening or stroke volume index were not. The attenuated Smax was compensated for the prolonged ejection time resulting in the relatively consistent fractional shortening regardless of body temperature. There was no compensatory mechanism for the decreased Dmax during diastole.

CONCLUSION

The effect of mild hypothermia seemed to be predominantly negatively chronotropic. LV diastolic function was more vulnerable to mild hypothermia than LV systolic function was.