The respiratory burst and electrolyte leakage induced by sulfhydryl blockers in egeria densa leaves are associated with H2O2 production and are dependent on Ca2+ influx

In leaves of Egeria densa Planchon, N-ethylmaleimide (NEM) and other sulfhydryl-binding reagents induce a temporary increase in nonmitochondrial respiration (DeltaQO2) that is inhibited by diphenylene iodonium and quinacrine, two known inhibitors of the plasma membrane NADPH oxidase, and are associated with a relevant increase in electrolyte leakage (M. Bellando, S. Sacco, F. Albergoni, P. Rocco, M.T. Marre [1997] Bot Acta 110: 388-394). In this paper we report data indicating further analogies between the oxidative burst induced by sulfhydryl blockers in E. densa and that induced by pathogen-derived elicitors in animal and plant cells: (a) NEM- and Ag+-induced DeltaQO2 was associated with H2O2 production and both effects depended on the presence of external Ca2+; (b) Ca2+ influx was markedly increased by treatment with NEM; (c) the Ca2+ channel blocker LaCl3 inhibited DeltaQO2, electrolyte release, and membrane depolarization induced by the sulfhydryl reagents; and (d) LaCl3 also inhibited electrolyte leakage induced by the direct infiltration of the leaves with H2O2. These results suggest a model in which the interaction of sulfhydryl blockers with sulfhydryl groups of cell components would primarily induce an increase in the Ca2+ cytosolic concentration, followed by membrane depolarization and activation of a plasma membrane NADPH oxidase. This latter effect, producing active oxygen species, might further influence plasma membrane permeability, leading to the massive release of electrolytes from the tissue.

Intestinal cytomegalovirus disease in immunocompromised patients may be ruled out by search for cytomegalovirus DNA in stool samples.

Cytomegalovirus (CMV) PCR from stool specimens was adopted as a diagnostic tool for patients with suspected CMV colitis. After being established, the method was evaluated in 17 AIDS patients and 19 other immunocompromised patients by comparison of PCR results with clinical, histological, and microbiological or virological data. CMV PCR was positive in 4 symptomatic patients with proven CMV colitis and negative in 15 of 16 patients without characteristic histopathology. Neither CMV immunoglobulin G seropositivity nor intestinal symptoms alone were significantly associated with positive PCR results, but severe active systemic CMV infection may lead to a positive PCR. Absence of CMV DNA in stool samples may prove useful in ruling out CMV related colitis.

[Pattern-induced flicker colors. An ophthalmologic examination method]. / Musterinduzierte Flimmerfarben (MIFF). Eine augenärztliche Untersuchungsmethode.

The pattern-induced flicker colours (PIFC), which belong to the subjective colours, are presented here as a method of investigating diseases of the eye and the visual track. Starting with Benham's top, new methods are elaborated for producing PIFC by means of rotating black and white discs and a computer-controlled black and white monitor. The investigations were performed in 40 normal and 111 pathological cases. A differentiation is made concerning the neuronal X-Y system. Different deficiencies result from different diseases. The PIFC are particularly suitable for the differential diagnosis of the neuritis nervi optici.

The pattern ERG in glaucoma: effect of pattern reversal time.

Pattern reversals with a ramp-like temporal course evoke transient pattern electroretinograms (PERG) that are delayed and attenuated in comparison with responses evoked by a step-like course (abrupt pattern reversals). This delay depends on the reversal time and probably represents a measure for temporal characteristics of the activated retinal structures. A pattern reversal stimulator with adjustable reversal periods (matrix of 8 x 14 rectangular red light emitting diodes, element size 2 degrees x 1 degree, stimulus area 16 degrees x 14 degrees) was used to record transient PERGs from 20 glaucomatous eyes with early or moderate visual field damages (measured with computer perimetry). The q-wave (P1) amplitude difference between the glaucoma group and normal subjects with step-like reversal stimulation was not significant (P = 0.23). On the other hand, a highly significant separation (P < 0.0001) between both groups was possible using the P1 latency at ramp-like stimulation or the response latency shift between step and ramp-like stimulation (Pattern reversal time, 30 ms).

Cortical potentials to pattern reversal and luminance onset under ramp stimulation conditions in glaucoma.

Stimulus quantities with a ramp-like temporal course evoke cortical potentials that are delayed and attenuated in comparison with responses evoked by a step-like course. This delay probably depends on temporal transfer characteristics of the activated precortical visual system. In a pilot study, luminance onset and pattern-reversal stimulation using this technique (light-emitting diode stimulator; transition time, 50 ms) were applied to 18 glaucomatous eyes with early visual field damage. The visual evoked cortical potential latency shifts between ramp and step mode were compared with visual field indices (mean defect, corrected loss variance). The pattern-reversal stimulation in ramp mode yielded a significant difference between the glaucoma group and normal subjects (p less than 0.004). The difference between groups with pattern-reversal stimulation in step mode was not significant (p = 0.15). From the determined visual field indices, only the mean defect showed a significant correlation to the measured visual evoked cortical potential latency shift, with both luminance-onset and pattern-reversal stimulation. In glaucoma with early malfunction, the precortical transmission and processing of lower and middle temporal frequencies, which are predominant in ramp-like temporal stimulus courses, are obviously more affected than the transmission of higher frequencies. The ramp stimulation technique for visual evoked cortical potentials might be of interest as a tool to detect early and specific functional defects in glaucoma.

[The Nagel anomaloscope in the diagnosis of eye diseases]. / Das Nagel-Anomaloskop in der Diagnostik von Augenerkrankungen.

The Nagel anomaloscope can be incorporated in the diagnosis of eye diseases. Three parameters are relevant: 1. The measure of the absolute matching range (scale units) 2. The preferred direction of the widened matching range (to red or to green) 3. The luminance matches with the yellow (decreasing matches indicating a pathologic scotopisation). - Six pathologic anomaloscope findings can be differentiated: 1. Pseudoprotanomaly (retinal diseases; type III acquired blue-yellow defects) 2. Symmetrically widened absolute matching range (reduced hue discrimination without reference to its etiopathology) 3. Absolute matching range asymmetrically widened to red with scotopisation (retinal diseases; type III acquired blue-yellow defects or type I acquired red-green defects) or without scotopisation (retinal diseases or optic nerve diseases; type III acquired blue-yellow defects) 4. Absolute matching range asymmetrically widened to green (mostly optic nerve diseases; type II acquired red-green defects) 5. Acceptance of both end matches ("0" up to "73") with scotopisation (retinal diseases) or without scotopisation (optic nerve diseases) 6. Achromatic matches (selective cone diseases, such as Stargardt's dystrophy or progressive cone dystrophy). Indications for anomaloscope examinations and clinical application of the method are discussed in ten cases. The utility of the Rayleigh-equation consists in diagnosing pathologic scotopisation (differential diagnosis between retinal diseases and optic nerve diseases) and in making a quantitative evaluation of the acquired color vision defect (follow-up examination).

[Measuring contrast sensitivity using visual acuity tests in retinal and optic nerve diseases]. / Messung der Kontrastempfindlichkeit mittels Sehschärfenprüfung bei Retina- und Optikuserkrankungen.

The luminance contrast needed to discern various test types was measured with monochromatic and achromatic light to detect discrete functional deficiencies of the retina and optic nerve in cases of normal visual acuity. Landolt rings corresponding to visual acuity levels from 0.04 to 1.0 were used as test types. A significant increase in the necessary minimum contrast was detectable with blue test light on large Landolt rings in patients with diabetic retinopathy, ocular hypertension and glaucoma and with green or yellow test light on medium-sized and small Landolt rings in patients with central serous chorioidopathy and optic atrophy. The additional contrast needed to reach the maximum visual acuity amounts to 14-100% compared with normal visual acuity, depending on the color of the test light and the diagnosis. The amount of contrast needed is greatest in retinal diseases, and it is therefore possible to a certain extent to distinguish these from diseases of the optic nerve.

[Friedrich August von Ammon (1799-1861) and Dresden ophthalmology in the 1st half of the 19th century]. / Friedrich August von Ammon (1799-1861) und die Dresdner Augenheilkunde in der ersten Hälfte des 19. Jahrhunderts.

Friedrich August von Ammon of Dresden took a considerable part in shaping ophthalmology into a scientifically and clinically independent part of medicine, thus inserting himself into the great development of the specialty during the first half of the 19th century. In particular, he investigated the ontogeny of the human eye as well as its pathological anatomy. He edited journals, published monographs, created a school of his own and gained in this way far-reaching influence. As a practitioner, a teacher and a physician-in-ordinary to the King of Saxony, he maintained the tradition of an earlier ophthalmologist of Dresden: Georg Bartisch.

[Early diagnosis of congenital disorders of color vision with the Velhagen "Pflügerhaken Color Charts for evaluating color perception" in 3,375 preschool children]. / Frühdiagnostik kongenitaler Farbensehstörungen mit den "Pflügerhaken-Tafeln zur Prüfung des Farbensinnes" von Velhagen bei 3375 Vorschulkindern.

In three series of examinations, 3375 male preschool-age children and 93 adult normal trichromates were tested using the Velhagen Pflügerhaken charts. The authors recommend modifying the evaluation of the results slightly by introducing a "doubteful" category for children who make one mistake or who show hesitation and lack of assurance in interpreting the charts. Using this modified form of assessment, diagnoses of "probably achromatopic" and "doubtful" were made in 7.16% and 2.13% respectively of 1689 preschool-age boys. The failure rate during the test and the duration of the examination were age-dependent, and declined with increasing age from 4.15% to 0.45% and from 1.18 min to 0.59 min, respectively. Most mistakes were made with charts nos. 9, 3, and 5. The results of tests with Pflügerhaken charts are fully comparable with those of other internationally used tests for adults. They can be recommended for screening preschool-age children.

Plasmalemma redox activity and h extrusion: I. Activation of the h-pump by ferricyanide-induced potential depolarization and cytoplasm acidification.

Ferricyanide reduction by Elodea densa leaves, in the dark, is associated with: (a) acidification of the medium; (b) decrease (about 0.2-0.3 units) of intracellular pH (measured in cell sap, cytoplasm, and vacuole); (c) depolarization of the transmembrane potential; (d) net efflux of K(+) to the medium. Ferricyanide-induced acid secretion is markedly increased by the presence of fusicoccin (FC), and this effect is severely inhibited by the proton pump inhibitors erythrosine B and vanadate. In the presence of ferricyanide FC-induced H(+) extrusion no longer requires the presence of K(+) in the medium. The (ferricyanide reduced)/(H(+) extruded) ratio varies from about 2, in the absence of FC, to about 1 when the toxin is present, and to more than 4, when ATP-driven H(+) extrusion is inhibited by erythrosine B or by vanadate. Fusicoccin markedly reduces K(+) release to the medium. The ratio (ferricyanide reduced)/(H(+) extruded + K(+) released) approaches unity under all of the three conditions considered. These results indicate that ferricyanide reduction depends on a plasmalemma system transporting only electrons to the extracellular acceptor, with consequent potential depolarization and cytoplasm acidification. Most of the protons released in the cytoplasm would be secondarily extruded by the ATP-driven pump, stimulated by both intracellular acidification and depolarization. K(+) efflux would depend on potential depolarization.

Plasmalemma Redox Chain and H Extrusion: II. Respiratory and Metabolic Changes Associated with Fusicoccin-Induced and with Ferricyanide-Induced H Extrusion.

Ferricyanide reduction by Elodea densa leaves is associated with a release of protons in the cytoplasm, a fraction of the increase in protons being then extruded by the ATP-driven proton pump (20). The data presented here show that ferricyanide induces a marked increase in O(2) uptake, additive to that induced by fusicoccin plus K(+), and here interpreted as depending on the utilization of ATP by the H(+) pump. Glucose 6-phosphate and malate levels are markedly increased by fusicoccin plus K(+). The simultaneous presence of ferricyanide reduces by about 50% the increase of malate, while it completely suppresses that of glucose 6-phosphate. The ferricyanide-induced decrease of malate is interpreted as due to the acidification of the cytosol associated with ferricyanide reduction, while the more marked decrease of glucose 6-phosphate might depend in part on the pH change and in part on a faster oxidation of this substrate. In fact, ferricyanide reduction is accompanied by a marked decrease of the incorporation into RNA ribose of C-1 as compared with C-2 of [(14)C]glucose. This suggests a stimulation of the release of C-1 as CO(2) at the level of the glucose 6-phosphate oxidation pathway, as expected if NADPH was the electron donor for ferricyanide reduction. These results are interpreted as confirming that the H(+) efflux associated with ferricyanide reduction depends on the activation of the ATP-driven plasmalemma H(+) pump. They also suggest that NADPH is used as an electron donor to some initial component of the plasmalemma redox system.

[Color vision in cataract, aphakia and pseudophakia]. / Farbensehen bei Katarakt, Aphakie und Pseudophakie.

Color vision examinations were performed using a clinical test battery and two spectral laboratory methods. With aphakia and iris-clip lenses (ICL) there were slight acquired blue-yellow defects six months to three years after surgery, especially when the more sensitive laboratory methods were used. They were possibly caused by photochemical damage to the retina or by a barrier deprivation syndrome. Color vision with posterior chamber lenses (PCL) was superior to that with ICL, and in aphakic subjects it was quite normal. In the clinical tests no differences could be found between PCLs of clear PMMA material and those with UV absorbing properties. Slight acquired blue-yellow defects in the immediate postoperative phase after implantation of PCLs can be attributed to postoperative irritation and are reversible. Lasting and severe blue-yellow defects indicate inflammation or macular edema.

H-pumping driven by the plasma membrane ATPase in membrane vesicles from radish: stimulation by fusicoccin.

The effect of fusicoccin on Mg:ATP-dependent H(+)-pumping in microsomal vesicles from 24-hour-old radish (Raphanus sativus L.) seedlings was investigated by measuring the initial rate of decrease in the absorbance of the DeltapH probe acridine orange. Fusicoccin stimulated Mg:ATP-dependent H(+)-pumping when the pH of the assay medium was in the range 7.0 to 7.6 while no effect of fusicoccin was detected between pH 6.6 and pH 6.0. Both basal and fusicoccin-stimulated H(+)-pumping were completely inhibited by vanadate and almost unaffected by nitrate. Fusicoccin did not change membrane permeability to protons and fusicoccin-induced stimulation of Mg:ATP-dependent H(+)-pumping was not affected by changes in the buffer capacity of the incubation medium. Deacetylfusicoccin stimulated H(+)-pumping as much as fusicoccin, while the physiologically inactive derivative 8-oxo-9-epideacetylfusicoccin did not. Stimulation of H(+)-pumping was saturated by 100 nanomolar fusicoccin. These data indicate that fusicoccin activates the plasma membrane H(+)-ATPase by acting at the membrane level independently of the involvement of other cell components. The percent stimulation by fusicoccin was the same at all ATP concentrations tested (0.5-5.0 millimolar), thus suggesting that with fusicoccin there is an increase in V(max) of the plasma membrane H(+)-ATPase rather than a decrease in its apparent K(m) for Mg:ATP.

Stimulation of Weak Acid Uptake and Increase in Cell Sap pH as Evidence for Fusicoccin- and K-Induced Cytosol Alkalinization.

In maize root segments fusicoccin induced a consistent increase in cell sap pH (taken as representative of vacuolar pH). This effect was markedly enhanced by the presence of K(+) in the medium, whereas in the absence of fusicoccin K(+) did not significantly influence cell sap pH. Treatment with a weak acid at 2 mm concentration inhibited the uptake of a different ((14)C-labeled) weak acid fed at a lower concentration, thus suggesting that acidification of the cytoplasm inhibits weak acid uptake. Fusicoccin and K(+) increased the rate of uptake of 5,5-dimethyloxazolidine-2,4-dione, butyric acid, or isobutyric acid slightly when fed separately, strongly when fed in combination. The synergism between fusicoccin and K(+) in stimulating weak acid uptake was parallel to that observed for the stimulation of H(+) extrusion. Application of the weak acid distribution method to a condition of ;quasi-equilibrium' indicated that fusicoccin induces a cytosolic pH increase of about 0.14 unit. These results are interpreted as providing circumstantial evidence that fusicoccin- and K(+)- induced stimulation of H(+) extrusion led to an alkalinization of the cytosol, and that other early metabolic responses, such as an increase in malate level, are a consequence of the increase in cytosolic pH.

H extrusion and potassium uptake associated with potential hyperpolarization in maize and wheat root segments treated with permeant weak acids.

The rapid uptake of weak acids permeant in the uncharged form is accompanied in maize and wheat root segments by a hyperpolarization of the transmembrane electrical potential and an increase in K(+) uptake, suggesting a stimulation of the plasmalemma H(+) pump. The evaluation of weak acid-induced H(+) extrusion must take into account the alkalinization of the medium due to the rapid uptake of the uncharged form of the acid, partially masking the proton pump-mediated extrusion of H(+). The data corrected for this interference show that the lipophilic butyric acid and trimethyl acetic acid induce in maize and in wheat root segments a significant increase in ;real' H(+) extrusion, roughly matching the increase in net K(+) uptake. The presence of K(+) significantly increases the rate of uptake of the weak acid, possibly as a consequence of an alkalinization of the cytosol associated with K(+) absorption. In maize root segments, the effects of fusicoccin and those of butyric acid on both K(+) uptake and H(+) extrusion are clearly synergistic, thus suggesting distinct modes of action. These results support the view that the activity of the plasmalemma H(+) pump is regulated by the value of cytosolic pH.

The proton pumps of the plasmalemma and the tonoplast of higher plants.

Studies on intact cells, membrane vesicles, and reconstituted proteoliposomes have demonstrated in higher plants the existence of an ATP-driven electrogenic proton pump operating at the plasmalemma. There is also evidence of a second ATP-driven H+ pump localized at the tonoplast. The characteristics of both these ATP-driven pumps closely correspond to those of the plasmalemma and tonoplast proton pumps of Neurospora and yeasts.

Quantitative evaluation of pallor-disc ratio and colour of the optic disc by a photographic method.

A photographic technique is described, which is based on simultaneous photography of the papilla with green and red filters by means of a stereoscopic fundus camera. Using black and white film, the negatives are photometrically measured and the pallor-disc ratio and colour of the papilla are calculated from the densitometric tracings. The latter parameter is quantitatively expressed by a numerical index. The method is demonstrated in a practical example.