Effects of microgravity and clinorotation on stress ethylene production in two starchless mutants of Arabidopsis thaliana.
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Arabidopsis↗
Biomedical subjects
C S Brown
Publications and source records attributed to C S Brown.
The Fluid Processing Apparatus: from flight hardware to electron micrographs.
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Calcium↗
Growth and photomorphogenesis of pepper plants under red light-emitting diodes with supplemental blue or far-red lighting.
Light-emitting diodes (LEDs) are a potential irradiation source for intensive plant culture systems and photobiological research. They have small size, low mass, a long functional life, and narrow spectral output. In this study, we measured the growth and dry matter partitioning of 'Hungarian Wax' pepper (Capsicum annuum L.) plants grown under red LEDs compared with similar plants grown under red LEDs with supplemental blue or far-red radiation or under broad spectrum metal halide (MH) lamps. Additionally, we describe the thermal and spectral characteristics of these sources. The LEDs used in this study had a narrow bandwidth at half peak height (25 nm) and a focused maximum spectral output at 660 nm for the red and 735 nm for the far-red. Near infrared radiation (800 to 3000 nm) was below detection and thermal infrared radiation (3000 to 50,000 nm) was lower in the LEDs compared to the MH source. Although the red to far-red ratio varied considerably, the calculated phytochrome photostationary state (phi) was only slightly different between the radiation sources. Plant biomass was reduced when peppers were grown under red LEDs in the absence of blue wavelengths compared to plants grown under supplemental blue fluorescent lamps or MH lamps. The addition of far-red radiation resulted in taller plants with greater stem mass than red LEDs alone. There were fewer leaves under red or red plus far-red radiation than with lamps producing blue wavelengths. These results indicate that red LEDs may be suitable, in proper combination with other wavelengths of light, for the culture of plants in tightly controlled environments such as space-based plant culture systems.
Biomass↗
Effects of clinorotation and microgravity on sweet clover columella cells treated with cytochalasin D.
The cytoskeleton of columella cells is believed to be involved in maintaining the developmental polarity of cells observed as a reproducible positioning of cellular organelles. It is also implicated in the transduction of gravitropic signals. Roots of sweet clover (Melilotus alba L.) seedlings were treated with a microfilament disrupter, cytochalasin D, on a slowly rotating horizontal clinostat (2 rpm). Electron micrographs of treated columella cells revealed several ultrastructural effects including repositioning of the nucleus and the amyloplasts and the formation of endoplasmic reticulum (ER) whorls. However, experiments performed during fast clinorotation (55 rpm) showed an accumulation (but no whorling) of a disorganized ER network at the proximal and distal pole and a random distribution of the amyloplasts. Therefore, formation of whorls depends upon the speed of clinorotation, and the overall impact of cytochalasin D suggests the necessity of microfilaments in organelle positioning. Interestingly, a similar drug treatment performed in microgravity aboard the US Space Shuttle Endeavour (STS-54, January 1993) caused a displacement of ER membranes and amyloplasts away from the distal plasma membrane. In the present study, we discuss the role of microfilaments in maintaining columella cell polarity and the utility of clinostats to simulate microgravity.
Actin Cytoskeleton↗
Chimeric parvovirus B19 capsids for the presentation of foreign epitopes.
Chimeric proteins consisting of the VP2 capsid protein of human parvovirus B19 and defined linear epitopes from human herpes simplex virus type 1 and mouse hepatitis virus A59 inserted at the N-terminus and at a predicted surface region were expressed by recombinant baculoviruses. The chimeric proteins expressed the inserted epitopes and assembled into empty capsids. Immunoelectron microscopy indicated that the epitopes inserted in the loop were exposed on the surface of the chimeric particles. The chimeric capsids were immunogenic in mice and antibodies specific for the inserted sequences were induced. In the case of MHV, antibodies were produced that recognized the epitope in the context of native virus. Mice immunized with the chimeric capsids were partially protected against a lethal challenge infection with either MHV or HSV.
Amino Acid Sequence↗
Porous Tube Plant Nutrient Delivery System development: a device for nutrient delivery in microgravity.
The Porous Tube Plant Nutrient Delivery System or PTPNDS (U.S. Patent #4,926,585) has been under development for the past six years with the goal of providing a means for culturing plants in microgravity, specifically providing water and nutrients to the roots. Direct applications of the PTPNDS include plant space biology investigations on the Space Shuttle and plant research for life support in Space Station Freedom. In the past, we investigated various configurations, the suitability of different porous materials, and the effects of pressure and pore size on plant growth. Current work is focused on characterizing the physical operation of the system, examining the effects of solution aeration, and developing prototype configurations for the Plant Growth Unit (PGU), the flight system for the Shuttle mid-deck. Future developments will involve testing on KC-135 parabolic flights, the design of flight hardware and testing aboard the Space Shuttle.
Capillary Action↗
Spectral quality may be used to alter plant disease development in CELSS.
Plants were grown under light emitting diode (LED) arrays with different spectral qualities to determine the effects of light on the development of tomato mosaic virus (ToMV) in peppers and powdery mildew on cucumbers. One LED array supplied 100% of the photosynthetic photon flux (PPF) at 660 nm, a second array supplied 90% of the PPF at 660 nm and 10% at 735 nm, and a third array supplied 98% of the PPF at 660 nm with 2% in the blue region (380-500 nm) supplied by blue fluorescent lamps. Control plants were grown under metal halide (MH) lamps. Pepper plants inoculated with ToMV and grown under 660 and 660/735 LED arrays showed marked increases in both the rate and the severity of symptoms as compared to inoculated plants grown under the MH lamp or 660/blue array. Pepper plants grown under the 660/blue array did not develop symptoms as rapidly as inoculated plants grown under the 660 or 660/735 arrays, but they did develop symptoms faster than inoculated plants grown under the MH lamp. The numbers of colonies of powdery mildew per leaf and the size of each colony were greatest on inoculated cucumber plants grown under the MH lamp.
Capsicum↗
Soybean cotyledon starch metabolism is sensitive to altered gravity conditions.
We have demonstrated that etiolated soybean seedlings grown under the altered gravity conditions of clinorotation (1 rpm) and centrifugation (5xg) exhibit changes in starch metabolism. Cotyledon starch concentration was lower (-28%) in clinorotated plants and higher (+24%) in centrifuged plants than in vertical control plants. The activity of ADP-glucose pyrophosphorylase in the cotyledons was affected in a similar way, i.e. lower (-37%) in the clinorotated plants and higher (+22%) in the centrifuged plants. Other starch metabolic enzyme activities, starch synthase, starch phosphorylase and total hydrolase were not affected by the altered gravity treatments. We conclude that the observed changes in starch concentrations were primarily due to gravity-mediated differences in ADP-glucose pyrophosphorylase activity.
Centrifugation↗
The influence of altered gravity on carbohydrate metabolism in excised wheat leaves.
We developed a system to study the influence of altered gravity on carbohydrate metabolism in excised wheat leaves by means of clinorotation. The use of excised leaves in our clinostat studies offered a number of advantages over the use of whole plants, most important of which were minimization of exogenous mechanical stress and a greater amount of carbohydrate accumulation during the time of treatment. We found that horizontal clinorotation of excised wheat leaves resulted in significant reductions in the accumulation of fructose, sucrose, starch and fructan relative to control, vertically clinorotated leaves. Photosynthesis, dark respiration and the extractable activities of ADP glucose pyrophosphorylase (EC 2.7.7.27), sucrose phosphate synthase (EC 2.4.4.14), sucrose sucrose fructosyltransferase (EC 2.4.1.99), and fructan hydrolase (EC 3.2.1.80) were unchanged due to altered gravity treatment.
Bacterial Proteins↗
Starch metabolism in germinating soybean cotyledons is sensitive to clinorotation and centrifugation.
Soybean (Glycine max [L.] Merr. cv. McCall) seedlings germinated and grew for 6d under the altered gravity conditions of horizontal clinorotation and centrifugation. Both of these conditions resulted in decreased growth relative to the control (vertically rotated) plants. Starch concentration in the cotyledons was lower in the clinorotated plants and was higher in the centrifuged plants compared to the controls. The opposite relationship was noted for total lipid concentration. Of the six starch metabolic enzyme activities measured, only ADP glucose pyrophosphorylase was affected by the gravity treatments; being lower in the cotyledons of the horizontally rotated plants and higher in the cotyledons of the centrifuged plants relative to the control values.
Centrifugation↗
Efficacy of an influenza hemagglutinin-diphtheria toxoid conjugate vaccine in elderly nursing home subjects during an influenza outbreak.
OBJECTIVE: To compare the efficacy of an influenza hemagglutinin-diphtheria toxoid conjugate vaccine with the commercially available influenza hemagglutinin-subunit vaccine in preventing influenza in older adults living in a nursing home. DESIGN: A prospective, randomized, double-blind vaccine trial with 5 months of follow-up after vaccination. SETTING: Fourteen Wisconsin nursing homes. PARTICIPANTS: Nursing home residents at least 65 years old who were able to give informed consent and were free of malignancy and not receiving immunosuppressive therapy. INTERVENTIONS: Participants received, by intramuscular injection, 0.5 mL of a trivalent influenza vaccine containing 15 micrograms each of A/Leningrad/360/86 (H3N2), A/Taiwan/1/86 (H1N1), and B/Ann Arbor/1/86 (HA) or 0.5 mL of an influenza vaccine containing the same antigens conjugated to diphtheria toxoid (HA-D). MEASUREMENTS: Blood was obtained pre- and 1 month post-vaccination to assess for any vaccine-induced antibody titer change. Clinical surveillance for respiratory illness was performed twice weekly for 5 months. A record was kept of all signs and symptoms of new respiratory illness, and a viral culture and acute and convalescent sera were obtained. RESULTS: 204 participants received HA and 204 received HA-D. Both groups had similar baseline antibody levels to all influenza antigens. HA-D recipients seroconverted more frequently based on serum neutralizing activity (P < 0.05), had a greater increase in geometric mean titer (GMT), and sustained the increase in antibody titer longer than HA recipients. Vaccine hemagglutinin recall was greater in a subset of HA-D recipients as measured by lymphocyte proliferative assays (P < 0.05). During an outbreak of influenza A (H3N2 A/Shanghai/11/87-like and A/Victoria/7/87-like), fewer HA-D (29/195) than HA (43/204) recipients had laboratory-confirmed infection (P = 0.053), and, of these, fewer HA-D-treated subjects had lower respiratory tract involvement (5/29 HA-D and 17/43 HA) (P = 0.022). CONCLUSIONS: HA-D was more immunogenic in institutionalized elderly recipients and produced greater protection from influenza infection. Superior protection may be due to HA-D's ability to stimulate and recruit antigen-presenting cells, thus enabling the recipient to achieve and maintain functional antibody titers.
Aged↗
Premenstrual syndrome.
Premenstrual syndrome is a cyclical disorder involving behavioral, emotional, and physical symptoms during the premenstruum. Because of its unknown etiology, a variety of treatment options exist; yet no therapy has consistently reduced symptoms. Most recent advances have occurred in relaxation techniques and psychotropic therapies.
Contraceptives, Oral↗
Efficacy of depot leuprolide in premenstrual syndrome: effect of symptom severity and type in a controlled trial.
OBJECTIVE: To determine whether depot leuprolide is effective in premenstrual syndrome (PMS) and whether symptom type or severity affects therapeutic or hormonal responses and the incidence of adverse events. METHODS: Twenty-five women who met strict diagnostic criteria for PMS completed a double-blind, placebo-controlled, 6-month crossover trial at a university medical center. Depot leuprolide (3.75 mg/month) or saline was administered intramuscularly for three consecutive treatment cycles. Efficacy, adverse events, and hormone concentrations were assessed at each visit. Repeated-measures analysis of variance was used to analyze continuous data, and ordinal and binary data were analyzed using nonparametric techniques. RESULTS: Depot leuprolide treatment was significantly more effective than placebo on all rating scales. Irritability, neurologic symptoms, breast tenderness, and fatigue were most responsive to treatment. Symptoms were reduced to follicular phase levels only in women without premenstrual depression. Those with moderate premenstrual depression improved but remained clinically symptomatic, whereas the group with severe premenstrual depression showed no improvement on any efficacy measure. Adverse events were lowest in those without premenstrual depression and highest in those with severe depression. Leuprolide suppressed estradiol and progesterone in most premenstrual depression groups but had varying effects on gonadotropins. CONCLUSIONS: Leuprolide treatment reduced both behavioral and physical symptoms and was well tolerated in the absence of severe premenstrual depression. Women should be evaluated for depression severity before receiving a GnRH agonist. The differential response to leuprolide suggests that it may possess diagnostic value in determining distinct subtypes of PMS.
Adolescent↗
Liposome-mediated delivery of gallium to macrophage-like cells in vitro: demonstration of a transferrin-independent route for intracellular delivery of metal ions.
Gallium (Ga) prevents the activation of macrophages and might be useful as an immunosuppressive agent. It is taken up by the malignant cells through the transferrin (Tf) receptor pathway, but this pathway may be insufficient in the case of non-malignant cells. We studied the Tf-independent, liposome-mediated delivery of Ga to macrophage-like cells in vitro by a growth inhibition assay. The growth inhibitory properties of Ga for other types of cells was also evaluated. Ga complexed with nitrilotriacetate (GaNTA) and encapsulated in DSPG-liposomes was 16 and 48 times more potent for RAW 264 cells than free GaNTA and Ga-nitrate, respectively. CV1-P cells were also somewhat sensitive to liposomal Ga, but other cell lines with lower endocytotic capacity were insensitive. The inhibition of RAW 264 cell growth induced by liposomal or free GaNTA was partially reversed with iron-loading of the cells, indicating that this form of Ga causes an intracellular iron deficiency similar to that produced by Tf-bound Ga. Our results indicate that encapsulation of Ga in negatively charged liposomes provides a transferrin independent route for intracellular delivery of the compound to macrophages, which is of special interest in the treatment of autoimmune diseases, such as rheumatoid arthritis.
Ammonium Chloride↗
Response of the Emit II amphetamine/methamphetamine assay to specimens collected following use of Vicks inhalers.
The possible cross-reactivity of l-methamphetamine (desoxyephedrine) to the Syva Emit II amphetamine/methamphetamine assay was evaluated in urine specimens collected from seven subjects using Vicks Inhalers. The subjects were six males and one female ranging from 24 to 47 years of age. Four subjects used the inhaler every two waking hours for five consecutive days, while three subjects inhaled hourly for three consecutive days. All urine voids were collected, totaling 150 specimens. All specimens were analyzed by the Emit II assay on a Hitachi 717 automatic analyzer with a 1000-ng/mL d-methamphetamine cutoff calibrator. None of the inhaler specimens produced an Emit II response equal to or greater than the cutoff calibrator; all were negative. Specimens producing the highest rates were further analyzed by chiral GC/MS. The highest concentrations of l-methamphetamine were observed in urines from two subjects inhaling hourly: 1390, 1290, and 740 ng/mL. These specimens were collected the evenings of the second and third day. When used as directed or even with double the daily dose, Vicks Inhalers did not cause false-positive results in urine tested with the Emit II Amphetamine/Methamphetamine assay.
Administration, Inhalation↗
Recombinant parvovirus B19 capsids as a new substrate for detection of B19-specific IgG and IgM antibodies by an enzyme-linked immunosorbent assay.
A new enzyme-linked immunosorbent assay for the detection of B19-specific IgG and IgM antibodies was established using B19 capsids synthesized in a baculovirus expression system. These B19 capsids, consisting of either coat protein VP2 alone or of both VP1 and VP2, have been shown to be similar to native virus in size and appearance. The results obtained for the detection of B19-specific antibodies showed good correlations with a radioimmunoassay which uses native B19 virus and an immunofluorescence assay based on insect cells expressing coat protein VP1. The course of the antibody response could be followed by determining the titers of sequential serum samples taken after a recent B19 infection. Both types of recombinant capsids form an excellent source of antigen for the detection of both B19 IgG and IgM antibodies and are a very promising substitute for native virus.
Antibodies, Viral↗
Localization of an immunodominant domain on baculovirus-produced parvovirus B19 capsids: correlation to a major surface region on the native virus particle.
An immunodominant region on baculovirus-produced parvovirus B19 VP2 capsids was localized between amino acids 259 and 426 by mapping the binding sites of a panel of monoclonal antibodies which recognize determinants on the particles. The binding sites of three monoclonal antibodies were fine-mapped within this antigenic domain. Six VP2-specific monoclonal antibodies recognized determinants common to both the empty capsids and native parvovirus. The defined antigenic region is most probably exposed on the native B19 virion and corresponds to part of the threefold spike on the surface of canine parvovirus particles.
Amino Acid Sequence↗
Cardiac surgery in the elderly: the critical care phase.
A growing number of elderly patients (aged 70 years and older) are seen in critical care units after valve surgery or coronary artery bypass grafting. While studies show that the elderly demonstrate overall successful results after cardiac surgery, the mortality and morbidity risks are higher than in younger adults. The elderly patient is more likely to experience postoperative complications, prolonging the recovery phase. Commonly reported postoperative complications include dysrhythmias, pneumonia, cerebral vascular accidents, and infection. Elderly surgical candidates must be evaluated preoperatively to determine risk factors that may affect the critical care recovery phase. The length of stay tends to be longer in the intensive care unit, requiring nursing care that takes the aging process into consideration. The following article focuses on trends in cardiac surgery in the elderly, physiologic factors that affect outcome and recovery, and nursing interventions aimed at preventing or limiting postoperative complications.
Aged↗