Overexpression of the CBF2 transcriptional activator in Arabidopsis suppresses the responsiveness of leaf tissue to the stress hormone ethylene.

The plant hormone ethylene affects myriad developmental processes ranging from seed germination to organ senescence, and plays a crucial role in plant resistance to environmental stresses. The C-repeat/dehydration-responsive element binding factor genes (CBF1-3) are transcriptional activators involved in plant low-temperatures responses; their overexpression enhances frost tolerance, but also has various pleiotropic effects on growth and development, mainly growth retardation and delay of flowering and senescence. We found that overexpression of CBF2 in Arabidopsis suppressed leaf tissue responsiveness to ethylene as compared with wild-type plants, as manifested in significantly delayed senescence and chlorophyll degradation. In wild-type plants, exposure to ethylene at 0.1 microl.l(-1) for 48 h caused 50% reduction in chlorophyll levels as compared to leaves held in air alone, whereas CBF2-overexpressing plants required an ethylene concentration of 10.0 microl.l(-1) to cause the same effect. Furthermore, continuous exposure to ethylene at 1.0 microl.l(-1) reduced chlorophyll content in wild-type leaves by 50% after 42 h but took 72 h in CBF2-overexpressing plants. Transcript profiling of ethylene receptors and signal transduction genes in leaves of wild-type and CBF2-overexpressing plants, by means of the Affymetrix ATH1 genome array, revealed only minor differences in gene expression patterns - insufficient to explain the observed responsiveness differences. Nevertheless, we found that overexpression of CBF2 significantly increased transcript levels of 17 ABA biosynthetic and responsive genes and, thus, may have affected leaf responsiveness to ethylene via contrasting interactions with other hormones, mainly ABA. Overall, the current findings suggest that overexpression of the CBF2 transcriptional activator in Arabidopsis may, at least in part, contribute to the observed delay of leaf senescence and enhanced plant fitness by suppressing leaf responsiveness to stress-regulated ethylene.

Effect of pulsed short-wave diathermy on pain and function of subjects with osteoarthritis of the knee: a placebo-controlled double-blind clinical trial.

OBJECTIVE: To examine the effects of pulsed short-wave diathermy (PSWD), delivered at an intensity sufficient to induce a thermal sensation and at an athermal intensity, in comparison with a placebo short-wave diathermy treatment, on reported pain, stiffness and functional ability and on mobility performance of patients with osteoarthritis of the knee. DESIGN: A placebo-controlled double-blind trial with sequential allocation of patients to different treatment groups. SETTING: Outpatient physiotherapy department. SUBJECTS: One hundred and three consecutive patients, mean age 73.7 (+/-6.6) years with osteoarthritis of one or both knees for at least three months. INTERVENTIONS: All participants received three 20-min-long treatments per week for three weeks. One group received PSWD with mean power of 18 W (thermal effect), one group received PSWD with mean power of 1.8 W (athermal effect), and one group received sham short-wave diathermy treatment. Patients were assessed before the initial treatment, immediately following the last treatment, and at a three-month follow-up. MAIN MEASURES: Outcome measures included the WOMAC Osteoarthritis Index, which assessed reported pain, stiffness, and functional ability, and four measures of mobility performance: Timed Get Up and Go test (TGUG), stair-climbing, stair, descending and a 3-min walk. RESULTS: A difference across time was observed for the pain and stiffness categories of the WOMAC Osteoarthritis Index (p = 0.033 and p = 0.008, respectively), with no differences between groups. No other significant differences across time or between groups were observed in any of the other measures. CONCLUSION: The findings do not demonstrate pulsed short-wave diathermy, as it is utilized in clinical settings, to be effective in the treatment of osteoarthritis of the knee.

Induction of Resistance to Penicillium digitatum in Grapefruit by the Yeast Biocontrol Agent Candida oleophila.

ABSTRACT The yeast Candida oleophila, the base of the commercial product Aspire, is recommended for the control of postharvest decay in citrus and pome fruit. Its modes of action include nutrient competition, site exclusion, and direct mycoparasitism. In the present study, we showed that application of Candida oleophila to surface wounds or to intact 'Marsh Seedless' grapefruit elicited systemic resistance against Penicillium digitatum, the main postharvest pathogen of citrus fruit. The induction of pathogen resistance in fruit was already pronounced 24 h after elicitation; it was distance, concentration, and time dependent and restricted to the peel tissue closely surrounding the yeast application site. The induction of pathogen resistance required viable yeast cells at concentrations of 10(8) to 10(9) cells ml(-1). Nonviable autoclaved or boiled yeast cells or lower yeast concentrations were ineffective in enhancing fruit disease resistance. Application of Candida oleophila cell suspensions to grapefruit peel tissue increased ethylene biosynthesis, phenylalanine ammonia lyase activity, and phytoalexin accumulation, and increased chitinase and beta-1,3-endoglucanase protein levels, indicated by western immunoblotting analysis. Scanning electron microscope observations revealed that spore germination and germ tube growth of Penicillium digitatum were markedly inhibited in wounds made near the yeast-treated sites. Overall, this study provides evidence that induced resistance against postharvest decay of citrus fruit should be considered an important component of the multiple modes of action of the yeast Candida oleophila.

Gene transfer by viral vectors into blood vessels in a rat model of retinopathy of prematurity.

AIMS: To test the feasibility of gene transfer into hyaloid blood vessels and into preretinal neovascularisation in a rat model of retinopathy of prematurity (ROP), using different viral vectors. METHODS: Newborn rats were exposed to alternating hypoxic and hyperoxic conditions in order to induce ocular neovascularisation (ROP rats). Adenovirus, herpes simplex, vaccinia, and retroviral (MuLV based) vectors, all carrying the beta galactosidase (beta-gal) gene, were injected intravitreally on postnatal day 18 (P18). Two sets of controls were also examined: P18 ROP rats injected with saline and P18 rats that were raised in room air before the viral vectors or saline were injected. Two days after injection, the rats were killed, eyes enucleated, and beta-gal expression was examined by X-gal staining in whole mounts and in histological sections. RESULTS: Intravitreal injection of the adenovirus and vaccinia vectors yielded marked beta-gal expression in hyaloid blood vessels in the rat ROP model. Retinal expression of beta-gal with these vectors was limited almost exclusively to the vicinity of the injection site. Injection of herpes simplex yielded a punctuate pattern of beta-gal expression in the retina but not in blood vessels. No significant beta-gal expression occurred in rat eyes injected with the retroviral vector. CONCLUSIONS: Adenovirus is an efficient vector for gene transfer into blood vessels in an animal model of ROP. This may be a first step towards utilising gene transfer as a tool for modulating ocular neovascularisation for experimental and therapeutic purposes.

Vascular endothelial growth factor and vascular adjustments to perturbations in oxygen homeostasis.

Development of microvascular networks is set to meet the metabolic requirements of the tissue they perfuse. Accordingly, impairment of oxygen homeostasis, either due to increased oxygen consumption or as a result of blood vessel occlusion, triggers compensatory neovascularization. This feedback reaction is mediated by a hypoxia- and hypoglycemia-induced vascular endothelial growth factor (VEGF). VEGF accumulates under stress as a result of increased hypoxia-inducible factor-1alpha-mediated transcription, stabilization of the mRNA, and the function of a hypoxia-refractory internal ribosome entry site within its 5'-untranslated region. Matching of vascular density to the metabolic needs of the tissue may include a process of hyperoxia-induced vessel regression. Thus newly formed vascular networks may undergo a natural process of vascular pruning that takes place whenever VEGF, acting as a vascular survival factor, is downregulated below the level required to sustain immature vessels. Immature vessels are particularly vulnerable and are selectively obliterated upon withdrawal of VEGF. The plasticity window for vessel regression is determined by a delay in the recruitment of periendothelial cells to the preformed endothelial plexus. Thus fine-tuning of microvascular density takes place mostly in the newly formed plexus, but the mature system is refractory to episodic changes in tissue oxygenation. These regulatory links may malfunction in certain pathological settings.

Uracil moiety is required for toxicity of the cyanobacterial hepatotoxin cylindrospermopsin.

A new natural derivative of the sulfated guanidinium zwitterionic toxin cylindrospermopsin, 7-epi-cylindrospermopsin, was recently isolated from the cyanobacterium Aphanizomenon ovalisporum (Forti). The toxicity of the molecule (LD50 ip 5 d), estimated by mouse bioassay, was 200 microg/kg mouse, a value similar to that of cylindrospermopsin. Treatment of cylindrospermopsin with chlorine solution or chlorine-related oxidants produced two new derivatives. The chemical structure of these products was elucidated by nuclear magnetic resonance (NMR) and mass spectrometry (MS) techniques and toxicity was determined. In the first derivative, the vinylic proton at position 5 of the pyrimidine ring was substituted by chlorine to yield 5-chlorocylindrospermopsin. The other product is a truncated one, where C-6 of the pyrimidine ring was oxidized to a carboxylic acid. A trivial name, cylindrospermic acid, was given to this compound. Both products showed no toxic effects even at doses 50 times higher than the LD50 of cylindrospermopsin (10 mg/kg mouse ip). Based on these results, the pyrimidine ring is postulated as the molecule component essential for the toxicity of cylindrospermopsin.

Clinical correlations in infants in the neonatal intensive care unit with varying severity of gastroesophageal reflux.

BACKGROUND: Gastroesophageal reflux (GER) is frequently a benign condition in infancy with spontaneous resolution. In the neonatal intensive care unit (NICU), however, it can add to neonatal morbidity if not adequately diagnosed and treated. The objective of the current study was to analyze factors associated with GER in infants in the NICU and correlate them with the severity of the disease. METHODS: All infants in the NICU (n = 150; born November 1994 through April 1999) who were evaluated by a five-channel pH study to rule out GER were included in the study. Infants were grouped as normal, with a reflux index (RI) of less than 6 (n = 66); mild, with RI of 6 to 14 (n = 42); and severe, with RI of more than 14 (n = 42). Maternal and neonatal data were obtained. Clinical GER was defined as the presence of feeding problems (significant gastric residue or emesis) and medical improvement with antireflux measures and medications. RESULTS: There was no difference in birth weight, gestational age; incidence of patent ductus arteriosus, intraventricular hemorrhage, necrotizing enterocolitis, or chronic lung disease; and treatment with aminophylline or caffeine among the groups. Infants with mild and severe GER (RI 6-14 and >14) had significantly more clinical GER than the normal group (P = 0.0001). Additionally, infants with RI more than 14 had significantly more respiratory distress syndrome, lower hematocrits at the time of study and longer length of stay than those with no or mild GER (P = 0.02). CONCLUSION: Infants with severe GER had lower hematocrits despite receiving more blood transfusions and iron therapy. Infants with severe GER also had prolonged hospital stays. Early diagnosis and aggressive management of GER may decrease neonatal morbidity and result in earlier discharge from the NICU.

Chloramine and copper sulfate as control agents of planktonic larvae of Chironomus luridus in water supply systems.

The latest approach to control of midge larvae in drinking-water supplies is suppression of the planktonic 1st-stage larvae, by using 2 disinfectants, chloramine and copper sulfate. The median lethal concentration for 24-h exposure of the 1st-stage larvae of Chironomus luridus to chloramine and copper sulfate individually was 0.51 and 0.38 mg/liter, respectively. The increase of copper sulfate to 0.5 mg of copper per liter to water containing chloramine (0.5 mg/liter) created a synergistic reaction that resulted in 96% (+/-8% SD) mortality of the planktonic larvae. This treatment may serve as an effective control of 1st-stage larvae in municipal drinking-water supplies.

Tissue oxygen levels control astrocyte movement and differentiation in developing retina.

Astrocytes play a key role in the development of retinal vessels by detecting hypoxia in developing retina and secreting the hypoxia-induced angiogenic factor VEGF to induce vessel formation. The astrocytes which play this role are themselves spreading over the retina, just ahead of the growing vessels. To understand the mechanisms which keep astrocytes in this strategic 'just ahead' position we have studied the effects of hyperoxia and hypoxia on astrocyte differentiation and movement in situ in neonatal rat retina and in primary culture. Hyperoxia in situ inhibited the stellation of astrocytes, so that they persisted in a relatively unbranched form, which accumulated at the edge of their spreading population; hyperoxia permitted but did not accelerate migration. Conversely, hypoxia induced unstellated astrocytes to stellate within 6 h. If the hypoxia was abnormally severe, it caused the astrocytes to hyperstellate and slowed their spread. Astrocytes in primary culture did not change morphology or motility when challenged by hypoxia. When treated with medium conditioned by retina however, astrocytes became mobile and, if the medium was conditioned by hypoxic retina, became stellate. These results suggest that the oxygen released by retinal vessels maintains the mobility of astrocytes, via a diffusible factor released by other retinal cells. Conversely, naturally generated hypoxia of developing retina plays a triple role, inducing astrocytes to stellate, to end their migration and to produce VEGF, thereby inducing vessel formation. The induction of stellation is mediated by a diffusible factor released by other retinal cells. Thus hypoxia of the retina generated by neural maturation induces key events in both the differentiation of astrocytes and the formation of blood vessels.

Clinical and inflammatory effects of dietary L-arginine in patients with intractable angina pectoris.

We evaluated the effects of oral L-arginine on the clinical outcome and the inflammatory markers of patients with intractable angina pectoris. Our findings demonstrated a significant clinical improvement in 7 of 10 patients, which was associated with a significant decrease in cell adhesion molecule and proinflammatory cytokine levels. Dietary L-arginine may have clinical beneficial effects in patients with intractable angina pectoris, and may have anti-inflammatory properties.

The effects of maternal magnesium sulfate treatment on newborns: a prospective controlled study.

OBJECTIVE: To evaluate the effects of maternal magnesium sulfate treatment on newborn outcome. METHODS: Subjects were newborn infants delivered at > or = 34 weeks of gestation whose mothers received a minimum of 12 hours of intravenous MgSO4 therapy before delivery. Control infants were the next born infants of similar gestational age. Outcome recorded at delivery included Apgar scores, whether resuscitation was required, and whether respiratory depression or decreased tone were noted by the physician in attendance. Pneumocardiograms on magnesium-exposed and control infants, obtained within 6 to 18 hours after delivery, were analyzed postdischarge by a single investigator who was blinded to group. The nursery course, feeding patterns, time to first stool, and time to first void were recorded. All patient care decisions, including admission to the neonatal intensive care unit (NICU) or term nursery, were independent of study protocol. RESULTS: A total of 26 magnesium-exposed and 26 control infants were enrolled. The mean total dose of MgSO4 before delivery was 51.2+/-24 gm; the mean duration of therapy was 23.1+/-10 hours. The mean maternal serum magnesium level before delivery was 5.8+/-1.1 mg/dl. The infants' mean cord or initial serum magnesium level was 5.2+/-1.0 mg/dl, which correlated with the maternal magnesium level before delivery (r=0.81, p < 0.001). MgSO4-exposed infants had a higher incidence of hypotonia and lower median Apgar scores than control infants (p < 0.001). However, there was no association between adverse outcomes and maternal serum magnesium concentrations at delivery, duration of treatment, or dose of MgSO4. No difference in dose or length of maternal MgSO4 treatment was noted between infants admitted to term nursery and those admitted to NICU. Pneumocardiogram data were similar between MgSO4-exposed and control infants (all p > or = 0.16). There were no significant differences in number of episodes of feeding intolerance or in time to first stool or void between MgSO4-exposed and control infants (all p > or = 0.31). CONCLUSION: Infants born to mothers treated with MgSO4 were more likely to be hypotonic and have lower Apgar scores at birth. Beyond the immediate postdelivery period, there were no additional complications in this cohort attributable to prenatal MgSO4 exposure. We suggest that pediatricians attend deliveries of magnesium-exposed infants.

Shock chloramination: potential treatment for Chironomidae (Diptera) larvae nuisance abatement in water supply systems.

In the early 1990s, infestations of midge larvae (Chironomidae, Chironomus sp.) were discovered in the potable water system of Tel Aviv, Israel. Control measures, such as draining and cleaning tanks, spraying water into the tank's air space, and electrocution traps of midge adults, were either inadequate or ineffective. In this system, monochloramine concentrations of up to 0.75 mg/liter are used routinely as a secondary disinfectant. This chemical was tested in the laboratory as a toxicant of midge larvae. The mortality of 4th instar midge larvae after short exposure to high chloramine concentrations (LC50 values of 32 mg/liter for 75 min) suggested the efficacy of instituting a Shock Chloramination treatment program. Tanks were partially drained until they contained only 20 cm of water and were then temporarily disconnected. Chloramine was added to this water to produce a concentration of approximately 70 mg/liter for 1-2 h. Subsequently, all dead chironomids were flushed out, and the tank was refilled to attain the operational volume of water. A 2nd identical treatment of water in the tank was suggested 7 d later to kill midges from reproductive adults and egg-masses that survived the 1st treatment. This treatment program was tested in commercial covered tanks and gave complete control of these pests for 6-10 wk. These results suggest that this treatment program may effectively prevent midge outbreaks in Israel's drinking water supply system during the height of the summer.

Arabidopsis SKP1, a homologue of a cell cycle regulator gene, is predominantly expressed in meristematic cells.

The yeast SKP1 gene and its human homolog p19skp1 encode a kinetochore protein required for cell cycle progression at both the DNA synthesis and mitosis phases of the cell cycle. In orchids we identified a cDNA (O 108) that is expressed in early stages of ovule development and is homologous to the yeast SKP1. Based on the orchid O 108 cDNA clone, we identified and characterized an Arabidopsis thaliana (L.) Heynh. cDNA designated ATskp1 that also has high sequence similarity to yeast SKP1. The Arabidopsis ATskp1 is a single-copy gene that mapped to chromosome 1. The expression of the ATskp1 gene was highly correlated with meristem activity in that its mRNA accumulated in all of the plant meristems including the vegetative shoot meristem, inflorescence and floral meristems, root meristem, and in the leaf and floral organ primordia. In addition, ATskp1 was also highly expressed in the dividing cells of the developing embryo, and in other cells that become multinucleate or undergo endoreplication events such as the endosperm free nuclei, the tapetum and the endothelium. Based on its spatial pattern of expression, ATskp1 is a marker for cells undergoing division and may be required for meristem activity.

PNZIP is a novel mesophyll-specific cDNA that is regulated by phytochrome and the circadian rhythm and encodes a protein with a leucine zipper motif.

We isolated and characterized a novel light-regulated cDNA from the short-day plant Pharbitis nil that encodes a protein with a leucine (Leu) zipper motif, designated PNZIP (Pharbitis nil Leu zipper). The PNZIP cDNA is not similar to any other gene with a known function in the database, but it shares high sequence homology with an Arabidopsis expressed sequence tag and to two other sequences of unknown function from the cyanobacterium Synechocystis spp. and the red alga Porphyra purpurea, which together define a new family of evolutionarily conserved Leu zipper proteins. PNZIP is a single-copy gene that is expressed specifically in leaf photosynthetically active mesophyll cells but not in other nonphotosynthetic tissues such as the epidermis, trichomes, and vascular tissues. When plants were exposed to continuous darkness, PNZIP exhibited a rhythmic pattern of mRNA accumulation with a circadian periodicity of approximately 24 h, suggesting that its expression is under the control of an endogenous clock. However, the expression of PNZIP was unusual in that darkness rather than light promoted its mRNA accumulation. Accumulation of PNZIP mRNA during the dark is also regulated by phytochrome, since a brief exposure to red light in the middle of the night reduced its mRNA levels. Moreover, a far-red-light treatment at the end of day also reduced PNZIP mRNA accumulation during the dark, and that effect could be inhibited by a subsequent exposure to red light, showing the photoreversible response attributable to control through the phytochrome system.

Transfer of cytokine-inducing bacterial products across hemodialyzer membranes in the presence of plasma or whole blood.

Cytokine production by peripheral blood mononuclear cells (PBMC) is a sensitive indicator of cytokine-inducing substances which may cross from contaminated dialysate into the blood compartment. The objective of this study was to compare the transfer of cytokine-inducing substances from dialysate contaminated with a culture filtrate from Pseudomonas aeruginosa across dialyzers with low (hemophan) or intermediate ultrafiltration coefficients (modified cellulose triacetate, CTA), under conditions where either 10% plasma or whole blood was circulated in the blood compartment. Eight paired experiments of in vitro dialysis were carried out at 37 degrees C using a countercurrent recirculating loop dialysis circuit with either a new CTA or hemophan dialyzer. 10% plasma in standard tissue culture medium was circulated through the blood compartment and bicarbonate dialysate was circulated in the dialysate compartment. The dialysate was challenged sequentially by log-fold dilutions (10(2), 10(3) or 10(4)) of a Ps. aeruginosa culture filtrate. Samples were drawn from the blood compartment 5 and 15 minutes after each challenge and incubated with suspensions of PBMC in the absence or presence of polymyxin B, in order to block endotoxin. After 24 h at 37 degrees C, total interleukin-1 alpha (IL-1 alpha) was measured by RIA. Although the dialysate contained potent cytokine-inducing substances, there was no significant IL-1 alpha production by PBMC incubated with the plasma mixture from the blood compartment in the majority of experiments with both dialyzers and with each of the three dilutions of the bacterial challenge. Eight experiments were also performed with CTA dialzyers using heparinized whole blood in the blood compartment. Samples of whole blood and dialysate were drawn at baseline, after one hour of dialysis with uncontaminated dialysate and 15 minutes and three hours after dialysis with dialysate contaminated with Ps. aeruginosa filtrate. There was no significant IL-1 alpha production by PBMC isolated from the whole blood 1 h after dialysis with uncontaminated dialysate, and 15 min and 2 h after adding the Ps. aeruginosa filtrate to the dialysate side. In contrast, production of IL-1 alpha by PBMC from the same donors incubated with samples from the dialysate were 263 +/- 50, 1074 +/- 306, 2333 +/- 774 and 2602 +/- 702 pg/2.5 x 10(6) PBMC, respectively at the same four time points. These data suggest that although the Ps. aeruginosa culture filtrate present in the dialysate was a potent inducer of IL-1 alpha, neither dialyzer permitted transfer of cytokine inducing substances from the dialysate into the blood compartment.

Identification of a meristem L1 layer-specific gene in Arabidopsis that is expressed during embryonic pattern formation and defines a new class of homeobox genes.

Homeobox genes are master regulatory genes that specify the body plan and control development of many eukaryotic organisms, including plants. We isolated and characterized a cDNA designated ATML1 (for Arabidopsis thaliana meristem L1 layer) that encodes a novel homeodomain protein. The ATML1 protein shares high sequence homology inside and outside of the homeodomain with both the Phalaenopsis O39 and the Arabidopsis GLABRA2 (GL2) homeodomain proteins, which together define a new class of plant homeodomain-containing proteins, designated HD-GL2. The ATML1 gene was first expressed in the apical cell after the first asymmetric division of the zygote and continued to be expressed in all proembryo cells until the eight-cell stage. In the 16-cell proembryo, the ATML1 gene showed a distinct pattern of expression, with its mRNA becoming restricted to the protoderm. In the torpedo stage of embryo development, ATML1 mRNA disappeared altogether but reappeared later only in the L1 layer of the shoot apical meristem in the mature embryo. After germination, this L1 layer-specific pattern of expression was maintained in the vegetative shoot apical meristem, inflorescence, and floral meristems, as well as in the young floral organ primordia. Finally, ATML1 mRNA accumulated in the protoderm of the ovule primordia and integuments and gradually became restricted in its expression to the endothelium surrounding the embryo sac. We propose that ATML1 may be involved in setting up morphogenetic boundaries of positional information necessary for controlling cell specification and pattern formation. In addition, ATML1 provides an early molecular marker for the establishment of both apical-basal and radial patterns during plant embryogenesis.

Methylene blue-induced phototoxicity: an unrecognized complication.

OBJECTIVE: To describe photosensitization after prenatal exposure to a toxic amount of methylene blue and to alert pediatricians that, in a review of the literature, photosensitization (which this dye is capable of) has not been reported as a complication of prenatal exposure. DESIGN AND PATIENTS: A descriptive report of physical findings and significant laboratory tests in a very low birth weight preterm infant with prenatal exposure to methylene blue and a comparison of this reported case with previously described patients' complications and treatment. SETTING: Neonatal intensive care unit. INTERVENTION: Monitoring of laboratory tests to assess for methylene blue toxicity: two exchange transfusions for methemoglobinemia, hemolytic anemia, and hyperbilirubinemia; phototherapy for hyperbilirubinemia; and pathologic examination of skin bullae. RESULTS: Within hours of exposure to phototherapy, redness developed on all exposed areas of the patient's skin (which was initially deep blue), followed by bullae and desquamation of about 35% of the total skin surface area. The desquamation of erythematous areas continued even after discontinuation of phototherapy. Complete re-epithelialization was attained by 3 weeks of age. In addition to this newly observed complication, the patient had other previously described toxic effects. CONCLUSION: We have reported a previously unrecognized complication associated with high prenatal exposure to methylene blue and treatment with phototherapy. Methylene blue phototoxicity may be related to the high prenatal dose of the dye relative to patient's small size and young gestational age.

Cytokine production by human peripheral blood mononuclear cells stimulated by a Pseudomonas aeruginosa culture filtrate: role of plasma and polymyxin B.

The lack of consensus regarding the significance of transmembrane passage of bacterial products across hemodialysis membranes can be related to several methodological differences in the various studies, including the choice of circulating fluid in the blood compartment of the model, nature and concentration of the bacterial products employed to challenge the dialysate compartment and whether cytokine production by PMBC or the limulus amebocyte lysate (LAL) assay was used as the index of transfer and the cytokine used as the read-out. In this study, we examined the production of interleukin-1 alpha (IL-1 alpha), interleukin-1 receptor antagonist (IL-1Ra) and interleukin-8 (IL-8) by peripheral blood mononuclear cells (PBMC) incubated with a Pseudomonas aeruginosa culture filtrate. Further, the effects of 10% autologous human plasma and Polymyxin B sulfate (PmB) on cytokine production by PBMC were also characterized. The results of our study indicate that the Ps. aeruginosa culture filtrate had both PmB suppressible and PmB non-suppressible components and that the addition of 10% human plasma significantly enhanced cytokine production by both PmB suppressible and PmB non-suppressible components. The enhancing effect of plasma was most evident at low concentrations of the filtrate. The inhibitory effect of PmB was most evident in samples cultured in the presence of 10% plasma. There was a direct correlation between the production of IL-1 alpha and IL-1Ra suggesting that both pro-inflammatory cytokines and cytokine-specific inhibitory proteins are concurrently produced. There results have direct relevance to selection of study conditions for in vitro models used to study the transmembrane passage of bacterial products across hemodialysis membranes.

Plasma cytokines, cytokine antagonists, and disease progression in African women infected with HIV-1.

OBJECTIVES: To examine the relation of circulating cytokines and cytokine antagonists to the progression of human immunodeficiency virus type 1 (HIV-1) disease. DESIGN: Cross-sectional analysis. SETTING: An ambulatory acquired immunodeficiency syndrome (AIDS) research clinic in Kinshasa, Zaire. PATIENTS: 48 women with AIDS, 51 women with HIV infection who were clinically asymptomatic, and 11 female controls who did not have HIV infection, all from Zaire. MEASUREMENTS: Plasma levels of interleukin-1beta, tumor necrosis factor-alpha (TNF-alpha), interleukin-6, interleukin-8, interferon-gamma, interleukin-1beta receptor antagonist (interleukin-1Ra), and TNF soluble receptor p55 (TNFsRp55) were assayed by specific radioimmunoassays. Plasma levels of interferon-gamma were assayed by commercial enzyme-linked immunosorbent assay. The Wilcoxon rank-sum test was used to assess the significance of mean and median differences between groups. RESULTS: Of the 48 patients with AIDS, circulating interleukin-1beta was detected in 2, TNF-alpha in 4, interleukin-6 in 3, and interleukin-8 in 12. None of these factors were seen in any of the 11 controls. Median values of interleukin-1beta (320 pg/mL), TNF-alpha (210 pg/mL), and interleukin-8 (750 pg/mL) were elevated in HIV-infected asymptomatic patients compared with patients with AIDS (2-, 2.6-, and 18.7-fold higher, respectively; P < 0.001). Interleukin-1Ra and TNFsRp55 levels were substantially higher than interleukin-1beta and TNF-alpha levels in HIV-infected asymptomatic patients (73- and 14-fold, respectively) and were higher than those in patients with AIDS (17.8- and 1.74-fold, respectively). CONCLUSION: High circulating levels of the proinflammatory cytokines interleukin-1beta and TNF-alpha, combined with an excess of their natural inhibitors interleukin-1Ra and TNF-sRp55, were seen in clinically asymptomatic HIV-1-positive African women but not in African women with AIDS or in HIV-negative controls. Circulating cytokine antagonists may play a clinical role in modulating cytokine-associated symptoms in the early phases of HIV infection.

PIP: At an outpatient AIDS research clinic in Kinshasa, Zaire, physicians conducted a medical examination and took blood samples from 48 women with AIDS, 51 women with asymptomatic HIV-1 infection, and 11 healthy HIV-1 seronegative women to study the relationship of circulating cytokines and cytokine antagonists to the progression of HIV-1 infection. Asymptomatic HIV-1-infected women had higher levels of the cytokines interleukin-1beta and tumor necrosis factor-alpha (TNF-alpha) than AIDS cases and controls (320 vs. 156 pg/ml, p 0.001, and 210 vs. 78 pg/ml, p 0.001, respectively) and even higher levels of interleukin-1Ra and TNFsRp55 (both natural cytokine antagonists) (4300 vs. 100 pg/ml, p 0.001; and 12,500 vs. 1450 for the AIDS group [p 0.0001] and 950 for controls [p 0.001]). The high levels of the two proinflammatory cytokines in asymptomatic HIV-1 infected women suggests that the high levels of antagonist cytokines blocked the clinical effects of interleukin-1beta and TNF-alpha. 46 AIDS patients had no detectable interleukin-1beta. 42 AIDS patients had no detectable TNF-alpha. The lack of cytokines in most AIDS patients suggests that persons in end-stage HIV-1 disease have a limited capacity to synthesize cytokines, perhaps depleting the remaining cytokine-producing central and peripheral lymphoid tissues. Asymptomatic HIV-1-infected women also had higher levels of interleukin-8 than AIDS cases and controls (750 vs. 40 pg/ml; p 0.001). 11 of the 13 highest values of interferon-gamma (11 pg/ml) belonged to AIDS patients rather than asymptomatic HIV-1-infected cases (p = 0.005). In the last 2 months, AIDS patients with detectable interferon-gamma had fever of longer duration than those with no interferon-gamma (17 vs. 9 days, p = 0.05), indicating that AIDS cases with interferon-gamma were still capable of responding to inflammatory stimuli. These findings suggest that cytokine antagonists may modulate cytokine-associated symptoms in the early phases of HIV-1 infection.