Estimation of photoparoxysmal response elicited by half-field visual stimulation

We examined photoparoxysmal responses (PPRs) elicited by half-field visual stimulation with deep-red flicker light to determine the neurophysiological features of photosensitive epilepsy (PSE). EEG revealed two types of PPRs. One had the focal spike in the occipital region and the other in the temporo-occipital region at the contralateral hemisphere. The equivalent current dipoles of these types were located at the occipital cortex and the inferior temporal (IT) cortex, respectively. These cortices comprise one of the main pathways in the visual system, and they play important roles in color discrimination. Thus, we propose that the visual system, especially the occipital cortex and the IT cortex, might be involved in the generator mechanism of PSE.     

Sound-induced laryngeal and respiratory reflexes originate from vestibular afferents

To determine whether the auditory or vestibular system causes the sound-induced laryngeal reflex, which has been considered to participate in the auditory feedback control of vocalization, click-induced laryngeal responses were compared before and after sectioning of the cochlear and/or vestibular nerves in cats. The sound-induced reflex modulation of respiratory muscle activity was also investigated, because respiratory movement is important for vocal control. Sectioning of the cochlear nerves had little influence on these responses. In contrast, sectioning of the vestibular nerves abolished these responses. It was concluded that the sound-induced laryngeal and respiratory reflexes are attributed to the vestibular system.     

Morbidity and mortality after 94 extrapleural pneumonectomies for empyema

BACKGROUND: Extrapleural pneumonectomy is still indicated in some patients with empyema. We examined morbidity and mortality after this high-risk operation. METHODS: Between 1979 and 1998, 94 (92 chronic, 2 postsurgical) patients with empyema underwent extrapleural pneumonectomy. There were 79 men and 15 women (mean age, 59 years). Eighty-eight patients had a history of tuberculosis, and 53 had undergone a therapeutic pneumothorax. The right side was operated on in 50 patients and left in 44. RESULTS: Operative mortality was 8.5%. Fifteen major complications (1 esophageal perforation, 9 empyemas, and 5 bronchopleural fistulas) occurred in 13 patients. Eight patients required reexploration for hemorrhage. Reexploration was a risk factor for empyema. Bronchopleural fistulas occurred only on the right side. Eighty-nine percent of the 86 operative survivors were free of empyemas at 5 years. Overall 5-year survival was 83%, and survival was better in patients without than in those with empyema. CONCLUSIONS: Extrapleural pneumonectomy for empyema has acceptable morbidity and mortality. Postoperative empyema affects prognosis. Covering a bronchial stump with muscle is recommended, especially when the operation is performed on the right side.     

CT appearance of implanted esophageal stents

Three different types of esophageal stents, the Z-stent, Ultraflex, and Wall-stent, exhibit different shapes on CT, which may suggest a difference in the radial forces applied by each of the stents. CT is useful for displaying the relationship between an esophageal stent and adjacent structures and complications.     

Evaluation of a method to determine the natural occurrence of aflatoxins in commercial traditional herbal medicines from Malaysia and Indonesia

Traditional herbal medicines, popularly known as ‘jamu’ and ‘makjun’ in Malaysia and Indonesia, are consumed regularly to promote health. In consideration of their frequent and prolonged consumption, the natural occurrence of aflatoxins (AF) in these products was determined using immunoaffinity column clean-up and high-performance liquid chromatography with pre-column derivatization. The evaluated method, which entails dilution of sample extracts with Tween 20–phosphate buffered saline (1:9, v/v) and a chromatographic system using isocratic mobile phase composed of water–methanol–acetonitrile (70:20:10, v/v/v), was effective in separating AFB₁, AFG₁ and AFG₂ from interference at their retention times. Results were confirmed using post-column derivatization with photochemical reactor. For 23 commercial samples analyzed, mean levels (incidence) of AFB₁, AFB₂ and AFG₁ in positive samples were 0.26 (70%), 0.07 (61%) and 0.10 (30%) μg/kg, respectively; one sample was positive for AFG₂ at a level of 0.03 (4%) μg/kg. In contrast to the high levels of AF in crude herbal drugs and medicinal plants reported previously by other researchers, the low contamination levels reported in this study may be attributed to the higher selectivity to AF of the method applied. Based on the AFB₁ levels and the daily consumption of positive samples, a mean probable daily intake of 0.022 ng/kg body weight was calculated.     

Pharmacological studies on pinacidil, a new antihypertensive agent. (3). Studies on the vasodilating effects in isolated monkey arteries and the peripheral hypotensive mechanism in SHR

Vasodilating effects of pinacidil in isolated monkey arteries were compared with those of nifedipine and hydralazine, and the relationship of the central nervous system to hypotensive and positive chronotropic effects of pinacidil in SHR was also studied. In arterial strips contracted with prostaglandin F2 alpha, the relaxant potencies of pinacidil were in the order of mesenteric = femoral greater than basilar = middle cerebral arteries, whereas those of nifedipine were middle cerebral = basilar = coronary greater than femoral arteries, and those of hydralazine were femoral greater than middle cerebral = coronary arteries. In pithed SRH, the hypotensive effect of pinacidil was dose-related, similar to hydralazine. Intravenous administration of 0.1 and 0.3 mg/kg of pinacidil in SHR demonstrated remarkable hypotension, whereas intracerebroventricular administration of the same doses did not show any significant effects. Therefore, the central autonomic nervous systems did not seem to take part in the hypotensive effects of pinacidil. The hypotension by intravenous administration of pinacidil in SHR was followed by an increase in heart rate. The increase in heart rate in conscious SHR was more marked than that in anaesthetized SHR. In pithed SHR, pinacidil did not show positive chronotropic effects even with the larger dose of 3 mg/kg, i.v. Propranolol pretreatment inhibited the increase in heart rate produced by pinacidil. These results show that activation of efferent sympathetic nerves via the baroreceptor. The peripheral hypotensive mechanism of pinacidil was supported by the present results.     

Effects of phospholipases C from bacteria on binding of enkephalin to rat brain membranes

The effects of phospholipases C on the equilibrium constants and maximal binding capacities of tritiated [D-Ala2,-D-Leu5] enkephalin to rat brain membranes were investigated using phosphatidylcholine-hydrolyzing phospholipase C and sphingomyelinase C of Bacillus cereus and, phosphatidylinositol-specific phospholipase C of Bacillus thuringiensis. When 72% of the phosphatidylinositol in the rat brain membranes was hydrolyzed by phosphatidylinositol-specific phospholipase C, the affinity of opiate receptor for [D-Ala2,-D-Leu5] enkephalin was almost doubled and maximal binding of [D-Ala2,-D-Leu5] enkephalin was decreased to 87% of control. Although specific [D-Ala2,-D-Leu5] enkephalin binding was decreased with phosphatidylinositol hydrolysis when measured at higher concentration (30 nM) of [D-Ala2,-D-Leu5] enkephalin, the specific binding was increased with the hydrolysis of phosphatidylinositol when measured at lower concentration (6 nM) of the ligand. On treatment of membranes with phosphatidylcholine-hydrolyzing phospholipase C, specific [D-Ala2,-D-Leu5] enkephalin binding was drastically decreased with the progressive hydrolysis of phosphatidylcholine in the rat brain membranes, and specific binding was completely lost after 81% hydrolysis of phosphatidylcholine. However, the affinity of opiate receptor for [D-Ala2,-D-Leu5] enkephalin was not influenced, and maximal binding was decreased to 32% of the control when 61% of phosphatidylcholine was hydrolyzed. Treatment with sphingomyelinase C did not cause any appreciable reduction of specific [D-Ala2,-D-Leu5] enkephalin binding. From these results, it is concluded that the binding of [D-Ala2,-D-Leu5] enkephalin to opiate receptor is influenced by changes in the phospholipid environment of the rat brain membranes, and that phosphatidylinositol may be a modulator for the function of the receptor.     

Studies on inhibitors of rat mast cell degranulation produced by microorganisms. II. Structure elucidation of eurocidins D and E

The planar structures of new eurocidin related compounds, eurocidins D and E, were elucidated from 1H-1H shift correlated 2D NMR spectra and other NMR data. All protons in the molecules were assigned. Eurocidins D and E have novel pentaenic structures of eurocidin family.