Phototaxis in the ciliated protozoan Ophryoglena flava: dose-effect curves and action spectrum determination.

The sensitivity of positive phototactic orientation of cells of the ciliated protozoan Ophryoglena flava has been measured for white light, broad-band blue and red light, and narrow-band monochromatic light, using a laboratory-developed computer aided system. The white-light fluence rate-response curve shows that there is no negative phototaxis in the fluence rate range investigated (0-15 W/m2) and no adaptation phenomena; it is very well fitted by a hyperbolic function; the fluence rate curves under broad band blue and red light (full width at half maximum, FWHM= 100 nm) can be fitted by the same model. The saturation level is, within experimental errors, the same for the three curves, indicating that there are no chromaticity effects and that if there is more than one photoreceptor pigment, they act independently of each other. The fluence rate-response curves determined under narrow band monochromatic light (FWHM = 10 nm) can also be fitted by the same model and show, within experimental errors, the same saturation level. An action spectrum for positive phototaxis at 10-nm intervals has been calculated from fluence rate-response curves: it shows three maxima, at 420, 540 and 590 nm. This action spectrum is significantly different from the ones for photomotile responses in Blepharisma japonicum, Stentor coeruleus and Chlamydodon mnemosyne, whereas it resembles the ones of Paramecium bursaria and Fabrea salina.

Immunological and biochemical evidence that blepharismin is not a prosthetic group.

A polyclonal, multispecific antiserum was raised against a whole 3[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate-extract of nonirradiated Blepharisma japonicum cells. It was used to reveal the composition of solutions that were hypothesized to contain the photoreceptor of the ciliate. A Bio-Gel A 1.5 m fine column chromatography of the extract allowed recovery of a single elution peak isolated by recording the 580 nm light absorbance. Fused-rocket immunoelectrophoresis of this material revealed a large number of > 300 kDa coeluted proteins. Blepharismin-rich material with a molecular mass of approximately 50 kDa, consisting of at least nine proteins was obtained when the same extract underwent preparative isoelectric focusing before column chromatography separation. Purification of the pigment obtained from light-exposed cells gave blepharismin-rich material with a molecular weight of approximately 200 kDa. Comparison of the materials obtained under the same conditions, either from the dark-kept or light-irradiated cells, by means of pore-gradient electrophoresis confirmed that proteins present in the two preparations were different. It revealed only a very small amount, if any, of proteins in the chromatography fractions with the highest absorbance at 600 nm. Results are discussed on the basis of the hypothesis that a specific blepharismin-binding protein does not exist in the protozoan.

The uptake, location and fluorescence of hypericin in bovine intact lens.

PURPOSE: To determine the uptake, location and fluorescence of hypericin, the active ingredient in St. John's Wort, in situ in the isolated intact calf lens. METHODS: The absorption and fluorescence spectra of hypericin 10(-5 ) M were measured in DMSO/phosphate buffer, pH 7.4) [PBS] (1/10 in volume) in the presence of alpha-crystallin (0.5 and 1.1 mg/ml). Bovine lenses were incubated in the dark for 24 hours in 10(-4) M hypericin in a DMSO/PBS (1/10 in volume) mixture. Diffused hypericin fluorescence emission was detected with a fluorescence stereomicroscope from the PBS washed lens surface. A lens-holder specially built for front-surface excitation-detection was used to measure fluorescence emission and excitation spectra of intact lenses incubated with hypericin solutions. RESULTS: As increasing concentrations of alpha-crystallin were added, the absorption and fluorescence spectra of hypericin in DMSO/PBS (1/10 in volume) changed, indicating a binding between the chromophore and the lens protein. Fluorescence emission spectra detected from the lens surface (lambda( em) = 601 and 651 nm; lambda(exc) = 550 nm) confirmed that hypericin does bind to the ocular tissues. CONCLUSIONS: The results we obtained in simplified model systems can provide clues to investigate the effects of hypericin on lens properties in physiological conditions. Hypericin could in fact bind to lens protein thus increasing the retention time of hypericin in the eye and possibly altering a-crystallin properties as a chaperone. Should therefore hypericin be taken up by the lens, this can be detected, non-invasively by its fluorescence. Therefore, ophthalmologists may use a slit-lamp or scanning fluorometry to monitor the uptake of hypericin in the eyes of patients using St. John's Wort or receiving high doses of hypericin while undergoing photodynamic therapy.

ELDONET--European Light Dosimeter Network. Structure and functions of the ELDONET server.

The European Light Dosimeter Network (ELDONET) project has been designed with the purpose of establishing an efficient system to monitor solar radiation in Europe, in as many as possible locations. This paper describes the structure of the server that collects and processes the data acquired by the different stations belonging to the network, and makes them freely available on the Internet to the scientific community. The server is able to receive data either via FTP from the Internet or via modem and to process them looking for errors or inconsistencies. Moreover, it automatically generates graphs, Web-pages and FTP archives. The server has been active for some years in testing mode and is now fully operative.

Angioedema due to angiotensin-converting enzyme inhibitors.

Angiotensin-converting enzyme (ACE) inhibitor associated angioedema was detected in 39 subjects (17%) of 231 consecutive patients examined in the last 5 years at our out-patient clinic for symptoms of angioedema without urticaria. In these patients, angioedema was most commonly localized to the face. The duration of ACE-inhibitor treatment at the onset of angioedema ranged from 1 day to 8 years with a median of 6 months. The time elapsed between onset of angioedema and withdrawal of ACE-inhibitor ranged from 1 day to 10 years with a median of 10 months. Delayed diagnosis is explained by the unusual characteristics of this adverse reaction: angioedema may start years after beginning the treatment and then it recurs irregularly. In fact, ACE-inhibitors seem to facilitate angioedema in predisposed subjects, rather than causing it with an allergic or idiosyncratic mechanism. Thus, while Cl-inhibitor levels are usually normal in subjects developing ACE-inhibitor-dependent angioedema, we found that ACE-inhibitors caused angioedema in Cl-inhibitor-deficient patients. Because the main inactivator of bradykinin is kininase II, which is identical with ACE, it is believed that bradykinin mediates ACE-inhibitor-dependent angioedema. We had the possibility to examine the plasma bradykinin levels in one ACE-inhibitor-treated patient during an angioedema attack and we found very high levels, but we did not find an increase of break-down products of high-molecular-weight-kininogen as observed during acute attacks in hereditary angioedema. Bradykinin fell to normal levels during remission after withdrawal of the drug. These observations indicate that in ACE-inhibitor-induced angioedema, contrary to hereditary angioedema, the reduction of bradykinin catabolic rate plays a predominant role.

Idiopathic nonhistaminergic angioedema.

PURPOSE: We sought to describe the characteristics of a group of patients with idiopathic nonhistaminergic angioedema and their response to prophylactic treatment with tranexamic acid. METHODS: We identified 25 patients (15 men and 10 women; age at diagnosis 16 to 77 years) who had idiopathic nonurticarial angioedema that was not prevented by histamine-1 (H1) blockers. Known causes of angioedema were excluded by clinical history, physical examination, and diagnostic tests. RESULTS: The median age at the onset of symptoms was 35 years (range 8 to 66). The frequency of attacks was > 12 per year for 16 patients, six to 11 per year for 6 patients, and one to five per year for 3 patients. All patients had cutaneous attacks, 13 (52%) reported swellings of the pharynx or larynx, and 5 (20%) had symptoms consistent with bowel angioedema. Because of the similarities between these patients and patients who are deficient in C1 inhibitor, the 15 patients with severe and frequent attacks were started on prophylactic treatment with the antifibrinolytic agent tranexamic acid, 1 g three times a day orally for 3 months, tapered according to its effectiveness. The symptoms of 11 patients decreased to less than one attack per year, and the remaining 4 patients had partial remissions (less than 4 attacks per year). Fourteen patients are still being treated with tranexamic acid. CONCLUSION: Patients with idiopathic nonhistaminergic angioedema appear to have similar clinical features and response to treatment with tranexamic acid as those who are deficient in C1 inhibitor. This suggests that those two forms of angioedema might have, at least in part, a similar pathogenesis.

Sensory perception and transduction of UV-B radiation by the ciliate Blepharisma japonicum.

A key question to answer studying the biological effects of ultraviolet radiation on planktonic micro-organisms is whether they can perceive UV-B radiation as a sensory signal, likewise they do with visible light. We have faced this problem performing an individual-cell analysis of Blepharisma japonicum photomotile responses to UV-B stimuli. Our results on spectral responsiveness and on the effects of a photoresponse inhibitor indicate that B. japonicum is capable to perceive and transduce UV-B radiation as an environmental sensory stimulus, which it escapes from gathering in shadowed areas. Similar UV-B avoidance motile reactions could serve as a behavioural defence mechanism contributing to avoid harmful overexposure to UV-B.

Relevance of lymphoproliferative disorders and of anti-C1 inhibitor autoantibodies in acquired angio-oedema.

We looked for autoantibodies to C1 inhibitor (C1-INH) and evaluated the relationship of their presence to the associated lymphoproliferative diseases and to the cleaved form of C1-INH in 13 patients with acquired C1-INH deficiency (acquired angio-oedema (AAE)). At the time of manifestation of angio-oedema symptoms or within a few years the following diseases were diagnosed: liver angioma (n = 1), M-components (n = 7, one of whom also had echinococcal liver cysts), breast cancer (n = 1), chronic lymphocytic leukaemia (CLL; n = 1); three patients had no associated disease. Anti-C1-INH autoantibodies, measured both as immunoglobulin binding to C1-INH immobilized onto microtitre plates (ELISA) and as plasma inhibitory activity of C1-INH function, were found in 12 patients. Binding of C1-INH to paraproteins, transferred to Immobilon after agarose gel electrophoresis, was detectable in five of seven M-components associated with AAE. Immunoblotting analysis of SDS-PAGE-separated plasma demonstrated that C1-INH circulated in the cleaved 96-kD form in the 12 patients with autoantibodies, but not in the one without. In conclusion, the large majority of our patients have autoantibodies to C1-INH. Circulating autoantibodies are necessary for the generation of cleaved C1-INH. The paraproteins associated with AAE are frequently autoantibodies to C1-INH and thus account for its consumption.

Substance P-like immunoreactivity in the frog dorsal root ganglia.

The distribution of substance P-like immunoreactivity was studied in the thoracic dorsal root ganglia of the frog Rana esculenta by immunohistochemistry. Substance P-like immunoreactivity was contained in approximately 50% of primary sensory neurons. The immunoreactive fibers arising from the cell bodies are collected in small bundles within the ganglia neuropil before entering the central and peripheral roots.

Neuroanatomical identification of the frog habenular connections using peroxidase (HRP).

A study of the habenular nuclei connections by means of horseradish peroxidase (HRP) has never been carried out in amphibia. In the present paper we have investigated the afferent projections of the left and right habenular nuclei of the frog Rana esculenta using this technique. Cells, labelled by HRP, were either in a Golgi-like pattern or in a granular pattern. It appears that the habenular nuclei on the two sides of the epithalamus do not show different connections even though they are morphologically asymmetric. In fact, each habenula is connected bilaterally with the septal area and the bed nucleus of the hippocampal commissure, and ipsilaterally with the hypothalamic areas, the entopeduncular nucleus, the periventricular gray of the third ventricle and the interpeduncular nucleus. However, the habenular commissure has typical commissural fibres which apparently do not involve the medial portion of the left habenula. The habenular connections in the frog are generally similar to those reported in the literature for mammals. In addition, our results show the possibility that HRP is transported both retrograde and anterograde.

Non-ependymal cilia in the habenulae and the interpeduncular nucleus of the frog tadpole.

Cilia of the 9 + 2 pattern are found electron microscopically in nonependymal cells of the habenulae and the interpeduncular nucleus of the tadpole of Rana esculenta at an early stage of development (8 mm length, head to tip of tail). A comparison is made between these and the ependymal and sensory cilia in the same specimens. The cilia project into the neuropil emerging from a perikaryon rich in free ribosomes and displaying a prominent Golgi apparatus. These perikarya contain dense core vesicles. Synapses with vesicles of the clear spherical type have been observed along the ciliary shaft. On a purely morphologic basis the authors hypothesize that these cilia, at least in this early ontogenetic stage, may extend considerably the conducting surface of the cell and represent a sensory structure which could be stimulated by terminal processes belonging to distantly located cells. In addition, they could also be involved in the trophic exchange of material with the adjacent structures.

Does lateral specialization apply to the frog's brain? An electron microscope observation.

The ultrastructure of polymorphic crystal-like inclusions occurring in the cytoplasm of neurons of only the medial portion of the left habenula has been studied in the adult frog Rana esculenta and in the tadpole with the use of three types of fixatives: osmium tetroxide, a mixture of aldehydes and potassium permanganate.