Association of Phosphatidylinositol 4-Kinase with the Plant Cytoskeleton

In eukaryotic cells, phosphatidylinositol 4-hydroxy kinase and phosphatidylinositol-4-phosphate 5-hydroxy kinase are responsible for the formation of the two second messenger precursors phosphatidylinositol-4-phosphate (Ptdlns(4)P) and phosphatidylinositol-4,5-bisphosphate (Ptdlns(4,5)P2). In plant cells, these kinases have been considered to be exclusively membrane associated, with the majority of activity residing in the inner leaflet of the plasmalemma. By sequentially extracting carrot protoplasts with the detergent Nonidet P-40 then more rigorously with Triton X-100, we were able to remove the activity of three separate plasma membrane marker enzymes and to demonstrate that a significant proportion of cellular Ptdlns 4-kinase is associated with the cytoskeleton. When only endogenous substrates were present, Nonidet P-40-permeabilized protoplasts and Nonidet P-40-extracted cytoskeletons displayed a pattern of lipid phosphorylation similar to that obtained with isolated plant membranes or permeabilized cells, whereas the Triton X-100-extracted cytoskeletons showed little or no activity. In contrast, when exogenous substrates were added, a major proportion of PtdlnsP formed was due to kinase activity associated with the cytoskeleton as well as nuclei. However, by subtracting the activity of isolated nuclei, it could be demonstrated that a significant proportion of the detergent-resistant Ptdlns kinase activity resides with the cytoskeletal fraction. These findings suggest that the pathways of polyphosphoinositide biosynthesis in plant cells should be reevaluated to take account of the cytoskeleton and that Ptdlns(4)P itself may play a unique role in modulation of plant cytoskeletal integrity and cellular signal transduction.

[Lipoprotein (alpha) as a risk factor for myocardial infarction]

Serum lipoprotein (alpha) [Lp(alpha)]was determined in 105 cases of myocardial infarction survivors (MIS). Lp(alpha) level in MIS was much more elevated as compared with that in healthy subjects and in a hypertension group. Lp(alpha) had no relation with apolipoprotein B and AI, cholesterol, triglyceride and high density lipoprotein cholesterol. It may be a significant and independent risk factor for coronary heart disease.

Delayed-focus pulses for magnetic resonance imaging: an evolutionary approach

An evolutionary algorithm has been used to design a family of shaped radiofrequency pulses giving uniform absorption-mode excitation across a predetermined frequency band. By allowing a free precession interval before signal acquisition, time is left for field gradients to be switched and for undesirable transients to decay.

[Synthesis of hexamethyl propylamine oxime and comparative study of its diastereoisomers]

This is a report on the synthesis of hexamethyl-propylene-amine oxime (HM-PAO), a new agent for regional cerebral blood flow (gamma CBF) imaging, the separation of its diastereoisomers (dl- and meso-HM-PAO), and a comparative study of three forms of Tc- 99m labelled HM-PAO (dl-, meso- and mixture-) in chromatography, mice biodistribution and rabbit imaging. The results showed that the Rf value of Tc-99m-dl-HM-PAO (0.8-1.0) on silica G thin layer chromatography with MEK as solvent was different from that of Tc-99m-meso-HM-PAO (0.6-0.8), and that the retention of dl- isomer in the brain was higher and more static than those of meso-and mixture HM-PAO but identical with Ceretec, a dl-HM-PAO kit manufactured by Amersham Inc., England. The primary clinical applications for gamma CBF SPECT imaging demonstrated a satisfactory result.

[Effect of radix Astragalus on the contents of collagen in the aorta and lung of old rats]

The result of experiments shows that the collagen contents in the aorta and lung of old rats are higher than in those of young rats, whereas the contents in the old rats given Radix Astragalus appear lower than those in the control group, close to those in young rats.

[Pharmacological studies on dingchuanning]

Dingchuanning has been found to increase markedly the perfusion of isolated lung of guinea-pig. It may produce a relaxing effect on the smooth muscles of the isolated trachea, bronchus and lung strips of guinea-pigs, as well as a prominent protective effect on the bronchial asthma induced by inhalation of bronchoconstrictors in conscious guinea-pigs. It also has significant expectorant and antianaphylactic effects and helps to inhibit markedly the SRS-A release from lung tissues and to counteract directly the activity of SRS-A.

[Comparative clinical study of herpes simplex encephalitis (HSE) and non-herpes simplex sporadic encephalitis (NHSSE)]

HSV specific antibody IgG was detected in the sera and CSF of 43 patients with sporadic encephalitis by the initial and follow-up tests with ELISA. Twelve cases of HSE were diagnosed, accounting for 27.8% of the cases of sporadic encephalitis, the clinical manifestations of HSE and NHSSE were compared. Differences were observed with regard to the age, general states, mental symptoms, disturbance of consciousness, and fatality rate. The abnormalities in EEG, CSF examination and CT scanning were found to be more severe in the HSE cases. It was concluded that these differences would be of use only as a diagnostic aid where as additional specific tests would be necessary for an accurate diagnosis of herpes simplex encephalitis.

Biaxial Extension Studies Using Inflation of Sheets of Unimodal Model Networks

Measurements of uniaxial extension and compression were made on model poly(dimethylsiloxane) (PDMS) [−Si(CH3)2−O−]x networks to examine the molecular theories of rubber elasticity. The stress-strain isotherms showed that the Flory-Erman theory of rubber elasticity is in good agreement with experimental data from extension to compression (α−1: 0.3–13), while the Mooney-Rivlin relation is useful only in a specific region of extension ratio (α−1: 0.3–0.8). The experimental results strongly support the theory of Flory-Erman, rather than those of phantom and affine networks. It is thus evident that the Flory-Erman theory of rubber elasticity is the more nearly correct.

[An observation of the anticancer activity of mitoxantrone hydrochloride injection]

Experimental results of anticancer activity of DHAQ.HCl are reported in this paper. It was discovered that DHAQ.HCl, mitoxantrone hydrochloride, had an obvious anticancer effect on the experimental tumor strains:Ehrlich ascites cancer, Sarcoma-180, Leukemia P388, etc., and that it was more effective to Leukemia P388 than to other strains. The anticancer activity of DHAQ.HCl was better than DHAQ (P less than 0.05). No side effect was observed on the local sites (s.c.) of tumor planted or drug injected. And also a good anticancer effect was observed on the sites of tumor planted by local injection. It is suggested that this observation can provide some information on the choice of routes of administration of this drug clinically.