Surgical aspects of pulmonary paragonimiasis

Pulmonary paragonimiasis is caused by the presence of the oriental lung fluke, Paragonimus westermani, within the lung parenchyma. The disease is indigenous to Korea. In a retrospective review of operative cases from 1972 through July 1979 at the National Medical Center in Seoul, Korea, eleven cases were analyzed. The mean age of the patients was 27 years, and all had a history of ingesting raw crustaceans. Diagnosis was based on history, positive skin test, and radiographic findings. The patients were treated with bithionil before undergoing surgery for severe pleural or pleuroparenchymal lung disease. There was one operative death. Long-term follow-up from 6 to 84 months indicated satisfactory results in ten patients. Our experience with this clinical entity forms the basis of this report.     

Stimulus motion propels traveling waves in binocular rivalry

State transitions in the nervous system often take shape as traveling waves, whereby one neural state is replaced by another across space in a wave-like manner. In visual perception, transitions between the two mutually exclusive percepts that alternate when the two eyes view conflicting stimuli (binocular rivalry) may also take shape as traveling waves. The properties of these waves point to a neural substrate of binocular rivalry alternations that have the hallmark signs of lower cortical areas. In a series of experiments, we show a potent interaction between traveling waves in binocular rivalry and stimulus motion. The course of the traveling wave is biased in the motion direction of the suppressed stimulus that gains dominance by means of the wave-like transition. Thus, stimulus motion may propel the traveling wave across the stimulus to the extent that the stimulus motion dictates the traveling wave's direction completely. Using a computational model, we show that a speed-dependent asymmetry in lateral inhibitory connections between retinotopically organized and motion-sensitive neurons can explain our results. We argue that such a change in suppressive connections may play a vital role in the resolution of dynamic occlusion situations.     

Solar Radiation Induces Non-Nuclear Perturbations and a False Start to Regulated Exocytosis in Cryptosporidium parvum

Stratospheric ozone depletion, climate warming and acidification of aquatic ecosystems have resulted in elevated levels of solar radiation reaching many aquatic environments with an increased deleterious impact on a wide range of living organisms. While detrimental effects on living organisms are thought to occur primarily through DNA damage, solar UV can also damage cellular proteins, lipids and signalling pathways. Cryptosporidium, a member of the eukaryotic phylum Apicomplexa, contain numerous vesicular secretory organelles and their discharge via regulated exocytosis is essential for the successful establishment of infection. Using flow cytometric techniques we demonstrate that solar UV rapidly induces sporozoite exocytosis resulting in a significant reduction in the ability of sporozoites to attach and invade host cells. We found that solar UV induced sporozoite membrane depolarization, resulting in reduced cellular ATP and increased cytosolic calcium. These changes were accompanied by a reduction in the internal granularity of sporozoites, indicative of apical organelle discharge, which was confirmed by analysis of sporozoites with an exocytosis-sensitive dye. The precise timing of apical organelle discharge in the presence of a compatible host cell is critical for sporozoite attachment and invasion. Our results demonstrate for the first time how solar UV radiation can interfere with exocytosis, a fundamental cellular process in all eukaryotic cells. We contend that not only may the forecast increases in solar radiation in both aquatic and terrestrial environments significantly affect members of the Apicomplexa, solar UV-induced membrane depolarizations resulting in cytosolic calcium perturbation may affect a wider range of eukaryotic organisms through antagonistic effects on a myriad of calcium dependant cellular functions.     

Effects of ginsenoside on pacemaker potentials of cultured interstitial cells of Cajal clusters from the small intestine of mice

Ginsenoside, one of the active ingredients of Panax ginseng, has a variety of physiological and pharmacological actions in various organs. However, little is known about the effects of ginsenosides on gastrointestinal (GI) motility. We studied the modulation of pacemaker potentials by ginsenoside in the interstitial cells of Cajal (ICCs) using the whole-cell patch clamp technique in the current clamp mode. Among ginsenosides, we investigated the effects of ginsenoside Rb1, Rg3 and Rf. While externally applied Rb1 and Rg3 had no effects on pacemaker potentials, Rf caused membrane depolarization. The application of flufenamic acid or niflumic acid abolished the generation of pacemaker potentials and inhibited the Rf-induced membrane depolarization. Membrane depolarization induced by Rf was not inhibited by intracellular application of guanosine 5′-[β-thio]diphosphate trilithium salt. Pretreatment with a Ca²⁺-free solution, thapsigargin, a Ca²⁺-ATPase inhibitor of the endoplasmic reticulum, U-73122, a phospholipase C inhibitor, or 2-APB, an IP3 receptor inhibitor, abolished the generation of pacemaker potentials and suppressed Rfinduced actions. However, treatment with chelerythrine and calphostin C, protein kinase C inhibitors, did not block Rf-induced effects on pacemaker potentials. These results suggest that ginsenoside Rf modulates the pacemaker activities of ICCs and therby regulates intestinal motility.     

Direct extraction of curvature-based metric shape from stereo by view-modulated receptive fields

Any computation of metric surface structure from horizontal disparities depends on the viewing geometry, and analysing this dependence allows us to narrow down the choice of viable schemes. For example, all depth-based or slant-based schemes (i.e. nearly all existing models) are found to be unrealistically sensitive to natural errors in vergence. Curvature-based schemes avoid these problems and require only moderate, more robust view-dependent corrections to yield local object shape, without any depth coding. This fits the fact that humans are strikingly insensitive to global depth but accurate in discriminating surface curvature. The latter also excludes coding only affine structure. In view of new adaptation results, our goal becomes to directly extract retinotopic fields of metric surface curvatures (i.e. avoiding intermediate disparity curvature).To find a robust neural realisation, we combine new exact analysis with basic neural and psychophysical constraints. Systematic, step-by-step ‘design’ leads to neural operators which employ a novel family of ‘dynamic’ receptive fields (RFs), tuned to specific (bi-)local disparity structure. The required RF family is dictated by the non-Euclidean geometry that we identify as inherent in cyclopean vision. The dynamic RF-subfield patterns are controlled via gain modulation by binocular vergence and version, and parameterised by a cell-specific tuning to slant. Our full characterisation of the neural operators invites a range of new neurophysiological tests. Regarding shape perception, the model inverts widely accepted interpretations: It predicts the various types of errors that have often been mistaken for evidence against metric shape extraction.     

Terpenoid,Benzenoid, and Phenylpropanoid Compounds in the Floral Scent of <Emphasis Type="Italic">Vanda</Emphasis> Mimi Palmer

Vanda Mimi Palmer is the product of a cross between Vanda Tan Chay Yan and Vanda tessellata. The flower of this hybrid produces a sweet-smelling fragrance during day time at the open-flower stage. This study aimed to investigate the floral scent constituents in Vanda Mimi Palmer. Scent emission analysis of this orchid was carried out at different time points in a 24-h cycle and also at different floral developmental stages. A comparison was also made on the volatiles emitted by Vanda Mimi Palmer and both of its parents. Gas chromatography-mass spectrometry (GC-MS) analysis showed that the scent of Vanda Mimi Palmer was dominated by terpenoid, benzenoid, and phenylpropanoid compounds. The identified terpenoids were ocimene, linalool oxide, linalool, and nerolidol; while the benzenoid and phenylpropanoid compounds were methylbenzoate, benzyl acetate, phenylethanol, and phenylethyl acetate. The emission of terpenoid, benzenoid, and phenylpropanoid compounds was developmentally and temporally regulated. Comparison of the volatiles emitted by both of its parents showed that the scent of Vanda Mimi Palmer is dissimilar to that of its fragrant parent, V. tessellata.