[Hair growth with dupilumab in alopecia areata universalis and atopic dermatitis]. / Haarwachstum unter Dupilumab bei Alopecia areata universalis und atopischer Dermatitis.

We report the case of a 46-year-old woman who has suffered from severe atopic dermatitis since early childhood and from alopecia areata totalis since she was 18 years old, which has now developed into alopecia areata universalis. After the introduction of therapy with the monoclonal antibody dupilumab, renewed hair growth of the scalp, face and lower legs was observed. Dupilumab blocks the α­subunit of interleukin (IL)-4 receptor and prevents the signaling cascade of IL­4 and IL-13. This leads to a reduction of Th2 immune response. The severe eczema and itching with difficulties falling and staying asleep decreased after just 14 days. The patient tolerates the drug without significant side effects and has a significantly improved quality of life. Patients with severe atopic dermatitis and alopecia areata could benefit twice from the use of dupilumab in the future.

[Differential diagnosis of left-sided thoracic venous catheters: case report of a persistent left superior vena cava]. / Differenzialdiagnose linksthorakaler Venenkatheter am Beispiel einer persistierenden linken oberen Hohlvene.

The differential diagnosis of left-sided thoracic central venous catheters is discussed in context with the cannulation of a persistent left superior vena cava. In this case the catheter tip was seen lying to the left of the spine on frontal chest X-ray. In addition to the descending aorta, differential diagnoses are a persistent left-sided superior vena cava as well as other smaller veins such as the left internal thoracic vein, the left superior intercostal vein, or the pericardiophrenic vein. The misplacement of a venous catheter in a pericardiophrenic vein may result in a fatal pericardial tamponade.

Passive entry of CO2 and its energy-dependent intracellular conversion to HCO3- in cyanobacteria are driven by a photosystem I-generated deltamuH+.

CO(2) entry into Synechococcus sp. PCC7942 cells was drastically inhibited by the water channel blocker p-chloromercuriphenylsulfonic acid suggesting that CO(2) uptake is, for the most part, passive via aquaporins with subsequent energy-dependent conversion to HCO3(-). Dependence of CO(2) uptake on photosynthetic electron transport via photosystem I (PSI) was confirmed by experiments with electron transport inhibitors, electron donors and acceptors, and a mutant lacking PSI activity. CO(2) uptake was drastically inhibited by the uncouplers carbonyl cyanide m-chlorophenylhydrazone (CCCP) and ammonia but substantially less so by the inhibitors of ATP formation arsenate and N, N,-dicyclohexylcarbodiimide (DCCD). Thus a DeltamuH(+) generated by photosynthetic PSI electron transport apparently serves as the direct source of energy for CO(2) uptake. Under low light intensity, the rate of CO(2) uptake by a high-CO(2)-requiring mutant of Synechococcus sp. PCC7942, at a CO(2) concentration below its threshold for CO(2) fixation, was higher than that of the wild type. At saturating light intensity, net CO(2) uptake was similar in the wild type and in the mutant IL-3 suggesting common limitation by the rate of conversion of CO(2) to HCO3(-). These findings are consistent with a model postulating that electron transport-dependent formation of alkaline domains on the thylakoid membrane energizes intracellular conversion of CO(2) to HCO3(-).

[Persistent chylothorax after fracture of the 12th thoracic vertebrae]. / Persistierender Chylothorax nach Fraktur des 12. Brustwirbelkörpers.

We report on a patient who suffered chylothorax 2 months after she had undergone internal fixation of a fracture of her 12th thoracic vertebral body. The pleural effusion was treated by insertion of a chest tube. The chylothorax was managed conservatively. The patient received protein-rich nutrition supplemented with medium-chain triglycerides. As the volume of chylous fluid drained from the pleura had not decreased after 2 weeks, the patient received total parenteral nutrition without any oral intake of calories. Chest X-rays documented the disappearance of the chylothorax. Reexpansion of the lungs was noted, and the costophrenic sinuses could be clearly visualised.

Sustained net CO2 evolution during photosynthesis by marine microorganisms.

BACKGROUND: Many aquatic photosynthetic microorganisms possess an inorganic-carbon-concentrating mechanism that raises the CO2 concentration at the intracellular carboxylation sites, thus compensating for the relatively low affinity of the carboxylating enzyme for its substrate. In cyanobacteria, the concentrating mechanism involves the energy-dependent influx of inorganic carbon, the accumulation of this carbon--largely in the form of HCO3(-)-in the cytoplasm, and the generation of CO2 at carbonic anhydrase sites in close proximity to the carboxylation sites. RESULTS: During measurements of inorganic carbon fluxes associated with the inorganic-carbon-concentrating mechanism, we observed the surprising fact that several marine photosynthetic microorganisms, including significant contributors to oceanic primary productivity, can serve as a source of CO2 rather than a sink during CO2 fixation. The phycoerythrin-possessing cyanobacterium Synechococcus sp. WH7803 evolved CO2 at a rate that increased with light intensity and attained a value approximately five-fold that for photosynthesis. The external CO2 concentration reached was significantly higher than that predicted for chemical equilibrium between HCO3- and CO2, as confirmed by the rapid decline in the CO2 concentration upon the addition of carbonic anhydrase. Measurements of oxygen exchange between water and CO2, by means of stable isotopes, demonstrated that the evolved CO2 originated from HCO3- taken up and converted intracellularly to CO2 in a light-dependent process. CONCLUSIONS: We report net, sustained CO2 evolution during photosynthesis. The results have implications for energy balance and pH regulation of the cells, for carbon cycling between the cells and the marine environment, and for the observed fractionation of stable carbon isotopes.

Quantitative evaluation of the role of a putative CO2-scavenging entity in the cyanobacterial CO2-concentrating mechanism.

This paper assesses the contribution of a postulated CO2-scavenging system to the efficient operation of the CO2-concentrating mechanism (CCM) in cyanobacteria. A quantitative model for the CCM is presented which incorporates an energy-dependent carbonic anhydrase-like entity located at or near the inner surface of the plasma membrane. This entity, which converts CO2 to HCO3- against the thermodynamic potential, scavenges CO2 leaking outward from the carboxysomes, and, further, converts CO2 entering from the medium to HCO3-, thus maintaining an inward diffusion gradient along which CO2 enters passively. The model resembles our earlier models in postulating that CO2 and HCO3- are not at equilibrium throughout the greater part of the cell, and that CO2 is generated in high concentration at carbonic anhydrase sites within the carboxysomes. The model further takes into account the concentric thylakoid membranes which surround the carboxysomes, and events in the periplasmic space and the unstirred layer surrounding the cell. Implications of the predicted steady state fluxes of CO2 and HCO3-, and of their steady state concentrations in various cellular compartments, are discussed. The plasma membrane carbonic anhydrase-like activity lowers the photosynthetic Km for external Ci, as well as decreasing the inorganic C 'leak', but it may not save on energy expenditure.

Low Activation State of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase in Carboxysome-Defective Synechococcus Mutants.

The high-CO2-requiring mutant of Synechococcus sp. PCC 7942, EK6, was obtained after extension of the C terminus of the small subunit of ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase (Rubisco). The carboxysomes in EK6 were much larger than in the wild type, but the cellular distribution of the large and small sub-units of Rubisco was not affected. The kinetic parameters of in vitro-activated Rubisco were similar in EK6 and in the wild type. On the other hand, Rubisco appeared to be in a low state of activation in situ in EK6 cells pretreated with an air level of CO2. This was deduced from the appearance of a lag phase when carboxylation was followed with time in cells permeabilized by detergent and subsequently supplied with saturating CO2 and RuBP. Pretreatment of the cells with high CO2 virtually abolished the lag. After low-CO2 treatment, the internal RuBP pool was much higher in mutant cells than in the wild-type cells; pretreatment with high CO2 reduced the pool in mutant cells. We suggest that the high-CO2-requiring phenotype in mutants that possess aberrant carboxysomes arises from the inactivated state of Rubisco when the cells are exposed to low CO2.

Evidence for a highly specific k/h antiporter in membrane vesicles from oil-seed rape hypocotyls.

We present evidence strongly suggesting that a proton gradient (acid inside) is used to drive an electroneutral, substrate-specific, K(+)/H(+) antiport in both tonoplast and plasma membrane-enriched vesicles obtained from oilseed rape (Brassica napus) hypocotyls. Proton fluxes into and out of the vesicles were monitored both by following the quenching and restoration of quinacrine fluorescence (indicating a transmembrane pH gradient) and of oxonol V fluorescence (indicating membrane potential.) Supply of K(+) (with Cl(-) or SCN(-)) after a pH gradient had been established across the vesicle membrane by provision of ATP to the H(+)-ATPase dissipated the transmembrane pH gradient but did not depolarize the positive membrane potential. Evidence that the K(+)/H(+) exchange thus indicated could not be accounted for by mere electric coupling included the findings that, first, no positive potential was generated when KSCN or KCl was supplied, even in the absence of 100 millimolar Cl(-) and, second, efflux of K(+) from K(+)-loaded vesicles drives intravesicular accumulation of H(+) against the electrochemical potential gradient. Neither was the exchange due to competition between K(+) and quinacrine for membrane sites, nor to inhibition of the H(+)-ATPase. Thus, it is likely that it was effected by a membrane component. The exchanger utilized primarily K(+) (at micromolar concentrations); Na(+)/H(+) antiport was detected only at concentrations two orders of magnitude higher. Rb(+), Li(+), or Cs(+) were ineffective. Dependence of tonoplast K(+)/H(+) antiport on K(+) concentration was complex, showing saturation at 10 millimolar K(+) and inhibition by concentrations higher than 25 millimolar. Antiport activity was associated both with tonoplast-enriched membrane vesicles (where the proton pump was inhibited by more than 80% by 50 millimolar NO(3) (-) and showed no sensitivity to vanadate or oligomycin) and with plasma membrane-enriched fractions prepared by phase separation followed by separation on a sucrose gradient (where the proton pump was vanadate and diethylstilbestrol-sensitive but showed no sensitivity to NO(3) (-) or oligomycin). The possible physiological role of such a K(+)/H(+) exchange mechanism is discussed.

Physiological and molecular aspects of the inorganic carbon-concentrating mechanism in cyanobacteria.

This paper reviews progress made in elucidating the inorganic carbon concentrating mechanism in cyanobacteria at the physiological and molecular levels. Emphasis is placed on the mechanism of inorganic carbon transport, physiological and genetical analysis of high-CO(2)-requiring mutants, the polypeptides induced during adaptation to low CO(2), the functional significance of carboxysomes, and the role of carbonic anhydrase. We also make occasional reference to the green algal inorganic carbon-concentrating mechanism.

Mitochondria Isolated from NaCl-Adapted Tobacco Cell Lines (Nicotiana tabacum/gossii) Maintain Their Phosphorylative Capacity in Highly Saline Media.

The in vivo functioning of mitochondria isolated from two tobacco cell lines in suspension culture (Nicotiana tabacum/gossii), wild type, and NaCl-adapted (A190), has been compared in the face of rising external salinity. The O(2) uptake of both state 3 and state 4 mitochondria was progressively inhibited with increasing external NaCl concentration in the case of both lines. Phosphorylation, however, was maintained at a higher level in the case of A190 mitochondria, as indicated both by stability of ADP:O ratio and rate of incorporation of (32)Pi. The superior phosphorylation performance of A190 mitochondria also emerged when phosphorylation was calculated per reducing equivalent, but not per unit DeltamuH(+) (electrochemical potential gradient for protons). However, the overall DeltamuH(+) was maintained at a higher level in A190 mitochondria due to the fact that the depolarization accompanying increase in external NaCl concentration was compensated for in A190 mitochondria by an increase in the transmembrane pH gradient, but not in wild type mitochondria. Increased proton permeability of the inner membrane is among the probable causes suggested for the loss of phosphorylation ability in wild type mitochondria; in contrast, A190 mitochondria maintain better membrane integrity under saline stress.

Na/H and k/h antiport in root membrane vesicles isolated from the halophyte atriplex and the glycophyte cotton.

Proton fluxes have been followed into and out of membrane vesicles isolated from the roots of the halophyte Atriplex nummularia and the glycophyte Gossypium hirsutum, with the aid of the DeltapH probe [(14)C]methylamine. Evidence is presented for the operation of Na(+)/H(+) and K(+)/H(+) antiporters in the membranes of both plants. Cation supply after a pH gradient has been set up across the vesicle membrane (either as a result of providing ATP to the H(+)-ATPase or by imposing an artificial pH gradient) brings about dissipation of the DeltapH, but does not depolarize the membrane potential as observed in similar experiments, but in the absence of Cl(-), using the DeltaPsi probe SCN(-). Cation/H(+) exchange is thus indicated. This exchange is not due to nonspecific electric coupling, nor to competition for anionic adsorption sites on the membrane, nor to inhibition of the H(+)-ATPase; coupling of the opposed cation and H(+) fluxes by a membrane component is the most likely explanation. Saturation kinetics have been observed for both Na(+)/H(+) and K(+)/H(+) antiport in Atriplex. Moreover, additive effects are obtained when Na(+) is supplied together with saturating concentrations of K(+), and vice versa, suggesting that separate antiporters for Na(+) and for K(+) may be operating. In the case of both Atriplex and Gossypium evidence was obtained suggesting the presence of antiporters in both plasmalemma and tonoplast.

Evidence for a Na/H Antiporter in Membrane Vesicles Isolated from Roots of the Halophyte Atriplex nummularia.

The ATP-dependent establishment of a positive membrane potential (measured as S(14)CN(-)-accumulation) in membrane vesicles isolated from the roots of Atriplex nummularia Lindl. was not inhibited by NaMes and KMes at concentrations up to 140 millimolar. On the other hand, the formation of DeltapH (measured as (14)C-methylamine accumulation or quenching of quinacrine fluorescence), was depressed by NaMes concentrations as low as 30 millimolar. Supply of NaMes after the DeltapH had been established brought about partial dissipation within 30 seconds. Extent of dissipation of DeltapH increased with NaMes concentration over the range tested (up to 180 millimolar). The H(+)/Na(+) exchange indicated by these results was not due to the creation of a Na(+) diffusion potential. Formation of DeltapH in these vesicles was stable to NO(3) (-) up to 100 millimolar; further, the dissipating effect of Na(+) supply was apparent on a DeltapH formed in the presence of 30 millimolar NO(3) (-). Additional evidence that the origin of the membrane vesicles observed in this investigation was not the tonoplast and was probably the plasmalemma included the vanadate sensitivity of the establishment of the membrane potential.

Generation of a membrane potential by electron transport in plasmalemma-enriched vesicles of cotton and radish.

Plasmalemma-enriched vesicles were isolated from cotton roots (Gossypium hirsutum L. cv Acala San Jose 2) and from germinating radish seeds (Raphanus sativa L. cv Tondo Rosso Quarantino). When 100 millimolar ascorbate was added to the grinding medium, the addition of ferricyanide to either preparation led to an inside positive membrane potential as measured by the accumulation of thiocyanate. It is suggested that electrons from ascorbate were being transported electrogenically across the membrane to ferricyanide, resulting in an accumulation of protons within the vesicle. The redox activity of the vesicles has some similarities to that occurring in intact cells, thus providing a simpler system to study the components and effects of transmembrane electron transport.

Effect of altered sink: source ratio on photosynthetic metabolism of source leaves.

When seven crop species were grown under identical environmental conditions, decreased sink:source ratio led to a decreased photosynthetic rate within 1 to 3 days in Cucumis sativus L., Gossypium hirsutum L., and Raphanus sativus L., but not in Capsicum annuum L., Solanum melongena L., Phaseolus vulgaris L., or Ricinus communis L. The decrease was not associated with stomatal closure. In cotton and cucumber, sink removal led to an increase in starch and sugar content, in glucose 6-phosphate and fructose 6-phosphate pools, and in the proportion of (14)C detected in sugar phosphates and UDPglucose following (14)CO(2) supply. When mannose was supplied to leaf discs to sequester cytoplasmic inorganic phosphate, promotion of starch synthesis, and inhibition of CO(2) fixation, were observed in control discs, but not in discs from treated plants. Phosphate buffer reduced starch synthesis in the latter, but not the former discs. The findings suggest that sink removal led to a decreased ratio inorganic phosphate:phosphorylated compounds. In beans (14)C in sugar phosphates increased following sink removal, but without sucrose accumulation, suggesting tighter feedback control of sugar level. Starch accumulated to higher levels than in the other plants, but CO(2) fixation rate was constant for several days.

Studies on H-Translocating ATPases in Plants of Varying Resistance to Salinity : I. Salinity during Growth Modulates the Proton Pump in the Halophyte Atriplex nummularia.

Membrane vesicles were isolated from the roots of the halophyte Atriplex nummularia Lindl. H(+)-translocating Mg(2+)-ATPase activity was manifested by the establishment of a positive membrane potential (measured as SCN(-) accumulation); and also by the establishment of a transmembrane pH gradient (measured by quinacrine fluorescence quenching). H(+)-translocation was highly specific to ATP and was stable to oligomycin. Growing the plants in the presence of 400 millimolar NaCl doubled the proton-translocating activity per milligram of membrane protein and otherwise modulated it in the following ways. First, the flat pH profile observed in non-salt-grown plants was transformed to one showing a peak at about pH 6.2. Second, the lag effect observed at low ATP concentration in curves relating SCN(-) accumulation to ATP concentration was abolished; the concave curvature shown in the double reciprocal plot was diminished. Third, sensitivity to K-2 (N-morpholino)ethanesulfonic acid stimulation was shown in salt-grown plants (about 40% stimulation) but was absent in non-salt-grown plants. Fourth, the KCl concentration bringing about 50% dissipation of ATP-dependent SCN(-) accumulation was 20 millimolar for salt-grown plants and 50 millimolar for non-salt-grown plants. Vanadate sensitivity was shown in both cases. No clear NO(3) (-) inhibition was observed.

Studies on H-Translocating ATPases in Plants of Varying Resistance to Salinity : II. K Strongly Promotes Development of Membrane Potential in Vesicles from Cotton Roots.

Mg(2+)-ATP-dependent H(+)-translocation has been studied in membrane vesicles derived from the roots of Gossypium hirsutum L. var. Acala San Jose 2. Establishment of a positive membrane potential was followed by measuring SCN(-) accumulation; establishment of DeltapH across the vesicle membranes by measuring quinacrine fluorescence quenching. High specificity for ATP was shown, and H(+)-translocation was oligomycin stable. The pH profile for H(+)-translocation showed an optimum at 5.5. The relationship between SCN(-) accumulation and ATP concentration was approximately Michaelian; the apparent K(m) was 0.7 millimolar. K-2-(N-morpholino)ethanesulfonic acid strongly promoted ATP-dependent SCN(-) uptake (up to 180% stimulation). The effect was not given by Na-Mes. Carbonyl cyanide p-trifluoromethoxyphenylhydrazone totally inhibited SCN(-) accumulation, both in the presence and absence of K-2(N-morpholino)ethanesulfonic acid. Vanadate at 200 micromolar inhibited SCN(-) uptake by about 10 to 40% in the absence of K(+), but more strongly in its presence (about 60%). NO(3) (-) at 100 millimolar inhibited initial rate of quinacrine quenching by about 25%. The NO(3) (-) insensitive fraction was activated by K(+); and inhibited by 200 micromolar vanadate to about 40%, provided K(+) was present. Saline conditions during the growth of the plants had no appreciable effect on the observed characteristics of H(+)-translocation.

Proton Fluxes as a Response to External Salinity in Wild Type and NaCl-Adapted Nicotiana Cell Lines.

Addition of 100 millimolar KCl, NaCl, or Na(2)SO(4) strongly promoted acidification of the medium by cells of Nicotiana tabacum/gossii in suspension culture. Acidification was greater in the case of NaCl-adapted than in that of wild type cells, and strikingly so in KCl medium when fusicoccin (FC) was present. Back-titration indicated that net proton secretion in KCl medium was increased 4-fold by FC treatment in the case of adapted cells; but was not even doubled in wild type cells. Membrane potential was higher in NaCl-adapted cells. FC treatment hyperpolarized wild, but not NaCl-adapted cells, suggesting a higher degree of coupling between H(+) efflux and K(+) influx in adapted cells; FC enhanced net K(+) uptake in adapted but not in wild cells. Acidification by cells suspended in 10 millimolar KCl was highly sensitive to vanadate, but that after addition of 100 millimolar KCl or NaCl was much less sensitive. Addition of 100 millimolar NaCl to wild type cells already provided with 10 millimolar KCl briefly accelerated, then slowed down the rate of acidification. If the addition was made after acidification had already ceased, alkalization was observed, particularly in the presence of FC. The results are consistent with the operation of a Na(+)-H(+) antiporter.

Effect of translocation-hindering procedures on source leaf photosynthesis in cucumber.

THREE TREATMENTS WHICH ALTERED TRANSLOCATION RATE WERE APPLIED TO CUCUMBER PLANTS: Girdling of source leaf petiole; removal of all aerial sinks; removal of all source leaves except one. Two different effects were observed, one short-term (during the initial 6 hours), and one long-term (detected after several days).The short-term effect was observed exclusively in girdled leaves and involved a reduction in (14)CO(2) fixation rate paralleled by an increase in stomatal resistance. The effects were maximal after 3 hours with subsequent recovery. Stomatal closure apparently resulted from the 5 to 10% water deficit temporarily detected in girdled leaves which probably induced the observed temporary increases in abscisic acid content. Kinetin counteracted the effects of girdling.The long-term effect was detected 3 days after girdling and 3 to 5 days after sink manipulation. An increase or decrease in (14)CO(2) fixation rate was observed when the sink-source ratio was increased or decreased respectively, accompanied by a respective decrease or increase in starch content. Changes in the relative amount of (14)CO(2) incorporated into various photosynthetic products were also observed. Stomatal closure was not involved, and the decrease in CO(2) fixation was not counteracted by kinetin.