茶叶叶绿体的嗜锇颗粒含量和适制茶类的关系

应用电子显微镜技术,从细胞亚显微水平研究了81个茶叶品种(或品系)的叶绿体内嗜锇颗粒的分布情况及其适制茶类的关系。结果表明,适制乌龙茶的茶树品种嗜锇颗粒含量都比较多,而有特殊香气的凌云白毛茶嗜锇颗粒含量高达100—46(平均值58),认为嗜锇颗粒含量与成茶香气有关,研究不同茶树品种的嗜锇颗粒含量可为茶树品种的成茶适制性和育成高香型品种的亲本选择提供参考依据。     

花椒果实分泌囊超微结构的研究

利用电子显微镜对花椒果实分泌囊的超微结构进行研究,表明分泌囊上皮细胞和鞘细胞的最显著特征是具许多含嗜锇物质的质体。这些质体内膜结构不发达,周围分布大量内质网槽库、含油滴的液泡和环状油滴。在此基础上,对质体的功能以及精油合成、贮存和转运的可能场所和途径进行了讨论。     

亚油酸铂靶向脂质体抗肿瘤特性的研究

用超声波制备了内部包裹亚油酸铂,表面有抗人乳腺癌单克隆抗体ＭｃＡｂＧｐ－１Ｄ８的亚油酸铂靶向脂质体和亚油酸铂非靶向脂质体,研究了这些脂质体绎腹部注射到荷瘤裸鼠之后的组织分布和抑瘤效果,实验结果表明,靶向脂质体亚油酸铂在肿瘤组织的含量明显高于游离亚油酸铂组;在肾,肝,肺,脾,心脏等器官中,前者的含量比后者有所降低,分别在接种癌细胞后６天,１２天和２４天,按６ｍｇ／ｋｇ的剂量分别注射ＰＢＳ,游离亚油酸     

ULTRASTRUCTURE OF THE FEEDING APPARATUS AND MYONEMAL SYSTEM OF THE HETEROTROPHIC DINOFLAGELLATE PROTOPERIDINIUM SPINULOSUM1

The feeding veil or pallium of the thecate heterotrophic dinoflagellate Protoperidinium spinulosum Schiller is a highly vesiculate membranous sac containing several arched, sometimes bifurcated microtubular ribbons. It originates from an internal microtubular basket, passes through a sphincter-like osmiophilic ring located inside the posterior flagellar pore, and emerges from the cell at that pore. The osmiophilic ring is part of an interconnected myonemal system (composed of two striated collars and several striated connectives) that is anchored to the pore plate and to two inward protrusions composed of minute sulcal plates. A related species, Protoperidinium punctulatum (Paulsen) Balech, also possesses a microtubular basket/osmiophilic ring complex. Elongate electron-dense bodies within the basket resemble digestive secretory granules found in other protists. Granular, electron-lucent microbodies clustered at the anterior end of the basket may also have a role in prey digestion. Dense membranous whorls observed within a P. spinulosum cell presented as it was preparing to initiate feeding indicate a condensed storage site for pallium membranes. A narrow microtubule-strengthened pseudopodal appendage found in two non-feeding cells constitutes the tow filament that serves as the initial linkage between the dinoflagellate and its food. The structures that constitute the pallium and pallium precursors, described here for the first time, are unlike those of other known protists, although some similarities with the dinoflagellate peduncle are evident. The existence of this unique system of organelles may have important ramifications in the search for evolutionary relationships among protists.     

Effect of Macrophage Elimination Using Liposome-Encapsulated Dichloromethylene Diphosphonate on Tissue Distribution of Liposomes

Abstract

Effect of macrophage elimination using liposomal dichloromethylene diphosphonate (C1₂MDP)1 on tissue distribution of different types of liposomes was examined in mice. Intravenously administration into mice with CI2MDP encapsulated in liposomes composed of phosphatidylcholine, cholesterol and phosphatidylserine exhibits a temporary blockade of liver and spleen function for liposome uptake. At a low dose of 90 (ig/mouse, the liposome uptake by the liver was significantly decreased. Such decrease was accompanied by an increase in liposome accumulation in either spleen or blood depending on liposome composition and size. Direct correlation between the administration dose of liposomal CI2MDP and the liposome circulation time in blood was also obtained even for liposomes with an average diameter of more than 500 nm. These results indicate that temporary elimination of macrophages of the liver and spleen using liposomal CI2MDP may prove to be useful to enhance the drug delivery efficiency of liposomes.     

Hepatic uptake and antihepatotoxic properties of vitamin E and liposomes in the mouse

Intravenous administration of soybean phosphatidylcholine liposomes containing different amounts of tocopherol acetate leads to a dose and time dependent increase of mouse liver tocopherol content, which was not observed when the preparation was given orally. When benzo[a]pyrene pretreated mice intoxicated with 400 mg/kg AAP were pretreated 2 h before with 1 g/kg phosphatidylcholine liposomes containing 4 mg/kg vitamin E acetate, these animals were protected against liver damage. Vitamin E alone or liposomes lacking vitamin E showed no protection. In an inflammatory liver disease model, i.e. fulminant hepatitis induced by intraperitoneal administration of 700 mg/kg galactosamine and 1 microgram/kg lipopolysaccharide phosphatidylcholine liposomes protected at a dose of 1 g/kg i.v. In this case, however, the protection was not due to the presence of vitamin E. These findings demonstrate the usefulness of phosphatidylcholine for liver protection and show that the protective spectrum is improved when they contain vitamin E. The data suggest that phosphatidylcholine is an excellent carrier for delivery of vitamin E to the liver.     

ENHANCEMENT OF NASAL ABSORPTION OF CALCITONIN LOADED IN LIPOSOMES

Intranasal administration of calcitonin-containing liposomes in rabbits was investigated to evaluate the in vivo calcitonin absorption performance. Plasma calcitonin concentrations and calcium levels were measured and pharmacokinetic parameters were calculated. The bioavailability of calcitonin resulted from the intranasal delivery formulations demonstrated an order of calcitonin-containing positively charged liposomes > calcitonin-containing negatively charged liposomes > calcitonin solution. The significant enhancement of bioavailability of calcitonin for positively charged liposomes may be due to the charge interaction of positively charged liposomes with the negatively charged mucosa surface. Marked accumulation of positively charged liposomes was found on the negatively charged nasal mucosa surface. The retention of positively charged liposomes on the nasal mucosa resulted in an increase of residence time with high local concentration of calcitonin for increase of absorption.     

多烯脂肪酸对磷脂胆固醇液晶态结构影响机理

用小角Ｘ 射线散射法、３１Ｐ 核磁共振技术和扫描隧道显微镜技术,对多烯脂肪酸多相脂质体的液晶态结构进行了研究。实验结果表明：胆固醇、多烯脂肪酸、非离子表面活性剂均对ＰＥ 脂质体的液晶态结构有明显的影响。在含有高效分散剂的磷酸缓冲溶液中制成的液晶态油酸多相脂质体和亚油酸多相脂质体均由片层六角相和片层立方相组成, 而蓖麻酸多相脂质体由立方六角相组成。     

Long-living liposomes as potential drug carriers

Neutral, unilamellar liposomes (vesicles) composed of a dialkyl analog of phosphatidylcholine and cholesterol, and containing ¹⁴C-maltose as entrapped marker, were administered intravenously to mice. After one and two days, radioactivity in blood and liver remained 3–4 times higher than after administration of liposomes of egg (diester) phosphatidylcholine and cholesterol. It appears that the vesicles were taken into liver cells by endocytosis, and that phospholipases are involved in the capture as well as in the breakdown of conventional liposomes. Liposomes that are semi-resistant to catabolic enzymes may become useful in the manipulation of drug delivery.     

The use of a liposomally entrapped enzyme in the treatment of an artificial storage condition

A model storage condition has been produced by the intraperitoneal administration of dextran to rats; dextran accumulates in the liver, in all cellular compartments, and remains there for an extended period because of the absence of a dextranase in rats. The intravenous administration of dextranase entrapped in liposomes produces a rapid decrease in the amount of dextran in the liver.     

CONTROL OF MITOCHONDRIAL TURNOVER UNDER THE INFLUENCE OF THYROID HORMONE

The effect of thyroid hormone on the turnover of mitochondrial DNA and protein was studied in rat heart and liver. Changes in turnover were observed in both thyroidectomized and normal rats following administration of thyroid hormone. In heart and liver the turnover of mitochondrial DNA and protein was slower in thyroidectomized rats than in normal rats. The turnover of mitochondrial DNA and protein was affected similarly following the administration of thyroid hormone, suggesting that mechanisms which control turnover of mitochondrial constituents may be predicated upon a major part of the mitochondrion. In heart a decreased rate of degradation contributes to the increase in total mitochondrial protein. Mitochondrial DNA, labeled before administration of thyroid hormone, turns over, after the start of thyroid hormone administration, at a different rate from that in newly synthesized DNA. The different turnover rates suggest that in liver the pre-existing population of mitochondria is being replaced by another population synthesized under new physiological conditions.     

Improvement of in vivo stability of phosphodiester oligonucleotide using anionic liposomes in mice

Antisense phosphodiester oligonucleotides (ODN) are unstable in biological fluids due to nuclease-mediated degradation and therefore cannot be used in most antisense therapeutic applications. We describe here an in vitro and in vivo stabilization of a 15 mer phosphodiester sequence using anionic liposomes. Two formulations have been studied: DOPC/OA/CHOL and DOPE/OA/CHOL (pH-sensitive liposomes). Our in vitro findings reveal the same stabilization effect in mouse plasma for both anionic liposomes. In vivo investigation showed a great protective effect for both formulations after intravenous administration to mice. By contrast with in vitro results, a higher protection of ODN was observed with DOPC/OA/CHOL liposomes compared to the DOPE/OA/CHOL formulation. The latter was degraded in blood (75% of the injected dose at 5 min) probably due to interactions with blood components, and the remaining (25% at 5 min) was distributed mostly to the liver and spleen. DOPC liposomes were remarkably stable in blood and were distributed more slowly to all studied organs (liver, spleen, kidneys and lungs). Intact ODN was still observed in some organs (liver, spleen, lungs), but not in blood, 24 hours after DOPC liposome administration. These results suggest that this antisense strategy using carrier systems may be applicable to the treatment of diseases involving the reticuloendothelial system.     

THE FINE STRUCTURE OF THE PURKINJE CELL

This paper describes the fine structure of the Purkinje cell of the rat cerebellum after fixation by perfusion with 1 per cent buffered osmium tetroxide. Structures described include a large Golgi apparatus, abundant Nissl substance, mitochondria, multivesicular bodies, osmiophilic granules, axodendritic and axosomatic synapses, the nucleus, the nucleolus, and the nucleolar body. A new and possibly unique relationship between mitochondria and subsurface cisterns is described. Possible functional correlations are discussed.     

Effect of liposomal antitumor preparation 5-(5',6'-benzocoumarin-3')-methylaminouracil hydrobromide on cytochrome P-450 in the microsomal liver fraction of tumor bearing rats

Cytochrome P-450 thermal inactivation rate, and content of protein sulfhydryl groups and cytochrome P-450 in the microsomal liver fraction of rats at different stages of Huerin's carcinoma growth were investigated. Liposomal form of BCU administration on the background of preliminary (for 2 hours) administration of phosphatidylcholine liposomes suspension was performed. The low level of cytochrome P-450, protein SH-groups in microsomal liver fraction and increase of the rate of transition of microsomal cytochrome P-450 in P-420 was shown in the dynamics of Huerin's carcinoma growth in an organism. Low microsomal cytochrome P-450 distraction was shown in the rat liver under conditions of antitumor liposomal preparation BCU injection on the 21st day after the transplantation of Huerin's carcinoma. At the same time nonliposomal BCU caused the opposite effect. The preliminary administration of phosphatidylcholine liposomes favours the approach of the investigated parameters to the control values on the terminal stages of tumour growth.     

THE EXCHANGE OF PHOSPHATIDYLCHOLINE AND OF PHOSPHATIDYLINOSITOL IN SHEEP BRAIN

—The exchange of phospholipids between liposomes and brain mitochondria has been studied in the presence of pH 5·1 supernatant fluids derived from rat, guinea pig, sheep and ox brains. The exchange phenomenon was similar to that observed in liver and heart, but phosphatidylinositol and not phosphatidylcholine was the most rapidly exchanging phospholipid. The phosphatidylcholine exchange activity was purified 186-fold from sheep brain and the protein fraction contained two major and several minor protein species. The phosphatidylcholine and phosphatidylinositol exchange activities have been shown to have very similar molecular weights and isoelectric points. However, their behaviour in response to changes in liposomal surface charge suggested that separate proteins might be involved in stimulating the exchange of the two phospholipid classes.     

STUDIES OF SPERMATOGENESIS IN THE HEPATICAE V. BLEPHAROPLAST DEVELOPMENT IN MARCHANTIA POLYMORPHA

Coaxial centrioles and a microtubule organizing center (MTOC) constitute each centrosome in spermatid mother cells of Marchantia polymorpha. During cell division the centrosome separates at its midregion and the two centrioles undergo a planar rotation that brings them to lie somewhat staggered and nearly parallel with their proximal ends embedded in osmiophilic granular material similar in appearance to that of the MTOC. Microtubules of the multilayered structure (MLS) arise in this material below the posterior centriole and parallel to its long axis. The rotation of centrioles and the initiation of S₁ tubules below the posterior centriole determine polarity of the incipient blepharoplast. Lower MLS strata are formed under the anterior centriole by the compaction of granular, osmiophilic matrix. Formation and growth of S₂ vertical lamellae occur at the left front edge of the MLS in association with MTOC-like matrix localized near the cell membrane. The MLS enlarges to about 0.4 μm wide by 0.6 μm long and is ovoid in outline except for a short distal projection underlying the posterior centriole. Subsequently the lamellae are transformed into homogenous, osmiophilic matrix that contributes directly to the expansion of all MLS strata including microtubules. The stratum of lamellae is interpreted as a planar MTOC subject to morphogenetic control. Each of the four strata grows proximally while the tapering distal projection lengthens beneath the posterior basal body. Dense matrix above the MLS, apparently elaborated by the S₂ layer, is organized into cartwheel and triplet components of the basal bodies’ proximal extensions. Organization of triplet tubules proceeds from proximal to distal toward preexisting triplets. Osmiophilic matrix contributes to the formation of microtubule keels and osmiophilic crests and may serve as a cementing material that stabilizes the spatial relationships of blepharoplast components. After full expansion of the MLS’ lower strata, the S₂ layer is reorganized into lamellae. Flagellar growth in Marchantia is postulated to involve a process whereby subunits or their precursors are elaborated by the MLS, translocated to the distal end of the flagellum and incorporated into the axonemal tubules. When MLS microtubules elongate to form a long, narrow band, the distal half of the S₂ layer is again in the osmiophilic matrix state.     

LIPOSOMES CONTAINING DOPAMINE ENTRAPPED IN RESPONSE TO TRANSMEMBRANE AMMONIUM SULFATE GRADIENT AS CARRIER SYSTEM FOR DOPAMINE DELIVERY INTO THE BRAIN OF PARKINSONIAN MICE

The active loading of liposomes with dopamine in response to an ammonium sulfate gradient was studied. This method can be regarded as a mean to more efficiently improve the liposomal dopamine/lipids ratio in comparison to conventional methods of liposome preparation. Trapping efficiency of dopamine into liposomes exhibiting a transmembrane ammonium sulfate gradient was shown to be dependent on liposome lipid composition, lipid concentration and temperature. Dopamine-containing liposomes with α-tocopherol in the lipid bilayer were shown to be stable at least for three weeks. It has been found that intraperitoneal (i.p.) administration of conventionally prepared dopamine-containing liposomes as well as liposomes with increased dopamine/lipid ratio may efficiently suppress the expression of parkinsonian symptoms in C57BL/6 mice with experimental parkinsonian syndrome. On the other hand, only through increasing of liposomal dopamine/lipid ratio the complete compensation of dopamine deficiency in the mice brain was achieved. The obtained data may be considered as biochemical evidence in favor of liposomes' ability to act as a carrier system for the delivery of dopamine into the brain.     

THE ROLE OF LIPIDS IN THE OBSERVED LACK OF PHOSPHATIDYLCHOLINE EXCHANGE IN MYELIN

Abstract— When exchange between liposomal phosphatidylcholine and that in a whole myelin fraction from guinea-pig brain was studied, very little exchange was observed. In order to investigate the reason for this phenomenon, myelin lipids in the Ca²⁺ form were prepared and subjected to sonication under the same conditions usually used to study phosphatidylcholine exchange. Despite the high cholesterol content in these extracts, this treatment produced liposomes of a size (12 nm Stoke's radius) similar to that of pure phosphatidylcholine liposomes. In this form, myelin total lipids were capable of undergoing exchange, and this was only demonstrable in the fraction containing phosphatidylcholine and that containing phosphatidylinositol. Since the level of acidic phospholipids in these total lipid extracts is potentially capable of producing 40% inhibition of phosphatidylcholine exchange (H ellings et al , 1974; B rammer & S heltawy , 1975), control experiments were carried out to ensure that the observed phosphatidylcholine exchange in the myelin lipid extract was not due to the loss of phosphoinositides. This was found to be the case, and it was concluded therefore that total myelin lipids, in the Ca²⁺ form, are capable of phosphatidylcholine exchange and that the observed lack of it in the whole myelin is due either to the effect of myelin proteins or the compact structure of the myelin membrane.
Calculations based on the difference between the rate of phosphatidylcholine exchange in the myelin liposomes and in the sonicated phosphatidylcholine liposomes indicated that the phosphatidylcholine is asymmetrically distributed in the myelin liposomes. Almost all the phosphatidylcholine seems to be present in the outer half of the bilayer.     

CT imaging with iopromide liposomes in a rabbit model

The aim of this study was to evaluate the computed tomography (CT)-imaging potential of iopromide-carrying liposomes (SPC/CH/SPG, 6:3:1) of approximately 200?nm in diameter in healthy rabbits and in rabbits with implanted liver tumors in an intraindividual comparison with iopromide. Normal rabbits and animals with VX2 tumors implanted into the liver received iopromide (600?mg of iodine/kg, bolus injection) and, 1 or 2 days later, iopromide liposomes (300?mg of iodine/kg, bolus injection or 10-minute infusion). CT imaging up to 1 hour after administration was performed, focusing on the aorta, vena cava, kidney, spleen, and liver. Pharmacokinetic parameters for CT enhancement were calculated. Detectability and delineation of liver lesions were assessed on a 4-grade scale, and differences were evaluated statistically. Using half the iodine dose, iopromide liposomes achieved similar blood-pool enhancement as iopromide. Detectability and delineation of liver lesions were easy/good in the arterial phase after iopromide injection, but poor in the venous and equilibration phases. Iopromide liposomes resulted in a long-lasting, good detectability and delineation of liver lesions similar or superior to that observed after iopromide in the arterial phase.     

ULTRASTRUCTURAL DEMONSTRATION OF CYTOCHROME OXIDASE ACTIVITY BY THE NADI REACTION WITH OSMIOPHILIC REAGENTS

A new method for the subcellular and cytochemical demonstration of cytochrome oxidase has been developed with the introduction of N-benzyl-p-phenylenediamine (BPDA) and the discovery that indoanilines are osmiophilic. These indoanilines produced upon oxidation of BPDA in the presence of naphthols are highly colored compounds that yield electron-opaque coordination polymers of osmium (osmium black) that are amorphous, insoluble in water, and in organic solvents. The best methods for preparing rat tissue were in decreasing order: fixation in formaldehyde solution, fresh tissue slices, and frozen sections of fresh or fixed tissue. Ultrathin sections were counterstained by bridging with the thiocarbohydrazide-osmium tetroxide (T-O) procedure for enhancing underlying membranous structures. Cytochrome oxidase activity was noted primarily in mitochondria and occasionally in sarcotubules of heart, in mitochondria and occasionally in infoldings of the plasma membrane of renal tubular cells, and in mitochondria and, to a great extent, in endoplasmic reticulum of hepatic cells. Cytochrome oxidase activity produced deposits in droplet form, whereas dehydrogenase activity resulted in uniform staining of mitochondrial cristae, as recently demonstrated with an osmiophilic tetrazolium salt. Even more recently we have succeeded in demonstrating cytochrome oxidase activity in nondroplet staining on mitochondrial cristae with an osmiophilic benzidine-type reagent that apparently polymerizes upon oxidation (to be published later).