[Analysis of spatial clustering of disease]

It is difficult to determine whether there is spatial clustering of disease if the geographical distribution of population is unknown. Permutation test reported in the paper can be used as a method to judge the spatial clustering with unknown distribution of a random sample of cases. Comparison of difference in frequency of small distances between pairs of cases and controls can show whether there is spatial clustering of the disease.

[Research on corneal thickness at multi-points in normal and myopic eyes]

The corneal thickness of the center and other 24 points were measured in 31 normal eyes and 246 myopic eyes. The results show that the mean central corneal thickness of the normal eye is 541 +/- 45.29 microns and that of the myopic eye, 544 +/- 35.01 microns. There are no significant differences in the central corneal thickness in comparisons between the left and right eye, between the male and female, among various age groups, and among various degrees of refractive error. However, with the increase of age and increase of myopic refractive error, the central corneal thickness gradually becomes thinner. There are differences in thickness among various directions, the superior direction being the thickest and the temporal inferior, the thinnest. From the center to the limbus, the thickness of the cornea gradually increases, but the values of the increase of the thickness are various in various directions, that should be paid attention to in radial keratotomy.

Liposome-mediated cytoplasmic delivery of proteins: an effective means of accessing the MHC class I-restricted antigen presentation pathway

Different types of liposomes have been employed to deliver soluble antigen for processing and presentation in the major histocompatibility complex class I-restricted pathway. Anionic pH-sensitive liposomes as well as cationic liposomes efficiently sensitize antigen-presenting cells for recognition by the class I-restricted cytotoxic T lymphocytes (CTL). Cytoplasmic delivery of liposome-entrapped antigen from an endocytic compartment allows the exogenous antigen to gain access to the class I presentation pathway. Cytoplasmic delivery, however, is probably not the only mechanism by which liposomes induce the class I-restricted CTL priming in vivo. Macrophages play a central role in the processing of the liposome-encapsulated antigens. The processed antigen fragments are probably released by the macrophages and taken up by the nearby dendritic cells for antigen presentation. Collaboration between the two types of immune cells with the help of the appropriate costimulatory factors is the central theme for this hypothesis. In this case, the host immune system utilizes the similar mechanism for other membranous, particulate antigens to process and present the liposomal antigens.

The internal ventricular venting loop catheter. A new, simplified, single cannulation approach for a ventricular assist system

The internal ventricular venting loop (IVVL) catheter is a coaxial, two lumen, bidirectional flow cannula introduced peripherally and advanced intraluminally to the pulmonary artery by its flow directed, balloon tipped inner tubing in a right ventricular assist system (RVAS), or to the left ventricle over a guide wire under fluoroscopy in a left ventricular assist system (LVAS). Its use was successfully tested in six acute canine experiments using a small IVVL catheter. Hemodynamic responses to increasing roller pump flow rates, to a maximum of 1 L/min, were initially measured. Then, hemodynamic changes to 600 ml/min, after left anterior descending artery ligation (in IVVL-LVAS) and 300 ml/min after right coronary artery ligation (in IVVL-RVAS) were regularly recorded every 15 min until cardiac arrest. The IVVL-LVAS was able to significantly decrease the pulmonary capillary wedge pressure, while the IVVL-RVAS was able to significantly decrease the central venous pressure. The IVVL system was able to partially unload the ventricles and restore about 33-60% of the cardiac output. However, it could not effectively support the heart during arrest. Thus, the IVVL catheter can facilitate simple and effective single cannulation for either RVAS or LVAS. This approach may enable ordinary cardiac centers to make use of already available blood pumps for temporary, inexpensive, and less invasive application of partially assisted circulation when intra aortic balloon pump assistance fails.

Characterization and kinetics of MHC class I-restricted presentation of a soluble antigen delivered by liposomes

We describe in this report the characterization and kinetics of MHC class I-restricted presentation of a soluble antigen delivered by liposomes. pH-sensitive liposomes delivered ovalbumin (OVA) to the class I pathway more efficiently than pH-insensitive liposomes; the latter showed competence in the class I-restricted sensitization only when a large antigen loading dose was used. Such sensitization of EL4 cells resulted from substantial delivery of the ingested liposomal OVA to the cytosolic compartment as revealed with immunogold electron microscopy. Most of the ingested liposomal OVA were rapidly catabolized and released into the extracellular medium. The residual processed antigen took about 2 h to egress to the cell surface for recognition by CTL. The liposome-mediated antigen presentation exhibited a transient kinetics which was manipulable with antigen dose. Brefeldin A, an ER-to-Golgi transport inhibitor, strongly inhibited such presentation. The antigens displayed on the cell surface could also be removed by a brief acid wash of the cells and subsequently reappeared on the surface if an intracellular pool of antigen existed at the time of acid wash.

[Analysis of fatty acid composition of spotted fever group rickettsiae isolated in China by gas chromatography]

In present paper, fatty acid composition of seven Chinese isolates of SFG rickettsiae and six prototype strains of SFG rickettsiae were analyzed by GC-MS. Tested prototype strains of SFG rickettsiae were R. sibirica (strains 232 and 246), R. conorii (Simko), R. rickettsi (R), R. akari (Kaplan), R. australis (W58); Chinese isolates were An-84, Se-85, W-88 (human strain), MT-84, FT-84 (D. nuttalli strain), TO-85 (ova of nuttalli) and Chinese reference strain -JH-74 (D. nuttalli). They were propagated in yolk sacs of embryonated hen eggs and purified by centrifugation in a 30%-36%-42% discontinuous renografin density gradient. The fatty acid composition of selected strains of SFG rickettsiae was analyzed by gas chromatography, and then comparison being carried out by single linkage on mini-computer. Identification of the strains was performed based on the results obtained from GC-MS. Results showed that the fatty acid profiles of all the isolates from China were quantitatively similar to that of R. sibirica and quite different from other prototype strains of SFG rickettsiae.

Molecular dynamics study of the proton pump cycle of bacteriorhodopsin

Retinal isomerization reactions, which are functionally important in the proton pump cycle of bacteriorhodopsin, were studied by molecular dynamics simulations performed on the complete protein. Retinal isomerizations were simulated in situ to account for the effects of the retinal-protein interactions. The protein structure employed was that described in Nonella et al. [Nonella, M., Windemuth, A., & Schulten, K. (1991) Photochem. Photobiol. 54, 937-948]. We investigated two mechanisms suggested previously for the proton pump cycle, the 13-cis isomerization model (C-T model) and the 13,14-dicis isomerization model. According to these models, retinal undergoes an all-trans-->13-cis or an all-trans-->13,14-dicis photoisomerization as the primary step of the pump cycle. From the simulations emerged a consistent picture of isomerization reactions and their control through the retinal-protein interactions which favors the 13,14-dicis isomerization model. Electrostatic interactions between the protonated Schiff base and its counterion are found to direct the stereochemistry of retinal in the photocycle: this and other interactions steer retinal toward the 13,14-dicis geometry in the primary photoreaction, toward the 13-cis geometry after its deprotonation, and to the all-trans isomeric form after its reprotonation. We also propose a catalytic mechanism involving hydrogen bonding of the Schiff base to main chain oxygen atoms of Val-49 and Thr-89 for the 13-cis-->all-trans thermal reisomerization of retinal. The all-trans-->13-cis primary photoreaction required by the "C-T" model was found to be inhibited by the Schiff base-counterion interaction, but the possibility of such a reaction can not be excluded. In order to investigate the "C-T" model, we enforced an all-trans-->13-cis photoisomerization in a simulation and monitored the subsequent protein conformational changes. The effects of internal water molecules on retinal isomerization reactions were studied by placing 16 water molecules in the proton conduction channel. The results indicate that water affects the nature of the Schiff base counterion and the nature of the primary photoreaction. Water chains, formed between positively and negatively charged protein groups in the proton conduction channel, are suggested to be involved in the reprotonation and deprotonation of retinal.

Monophosphoryl lipid A enhances specific CTL induction by a soluble protein antigen entrapped in liposomes

Exogenous soluble antigen loaded in membranous vehicles including splenocytes and liposomes can induce a CD8+ cytotoxic T-lymphocyte (CTL) response in mice. Plain liposomes of simple composition, however, are not as effective as cellular vehicles such as splenocytes. In the present study it is shown that incorporation of monophosphoryl lipid A (MPL), a semisynthetic bacterial adjuvant, into liposomes enhanced the ability of liposomal ovalbumin (OVA) to prime for a specific CTL response. With the MPL formulation, the minimal antigen dose required for a detectable CTL induction was reduced about fivefold, and this approximated the required minimal dose of OVA loaded in the splenocytes. Moreover, liposomes containing MPL could induce a considerable level of CTL activity by either an intravenous, intramuscular or subcutaneous immunization protocol, whereas liposomes without MPL could only elicit such a response by an intravenous injection route. Subcutaneous injection of a mixture of liposomes containing MPL and liposomes containing antigen also elicited specific CTL activity. However, simultaneous subcutaneous administration of liposomal MPL and liposomal OVA at two distant sites did not prime the mice for a CTL response. These results indicate that MPL, although not necessarily incorporated in the same liposomes, must be in close proximity to the antigen to exert its adjuvant activity. Based on the results of this model antigen study, it is suggested that an optimal CTL inductive vaccine should include immunomodulatory adjuvant in addition to a class I pathway delivery vehicle such as liposomes.

Thermodynamic integration calculations of binding free energy difference for Gly-169 mutation in subtilisin BPN'

The binding free energy difference for the Gly-169-->Ala-169 (G169A) mutation in subtilism BPN' complexed with a tripeptide substrate analogue is explored using the thermodynamic integration approach. The structure of the mutant enzyme-substrate complex obtained from free energy simulation is in good agreement with experimental X-ray refinement. The near perfect reversibility is obtained in the present work for ensuring the correctness of the free energy calculations. The results of the binding free energy difference are close to similar experimental data.

Prolonged survival of thymoma-bearing mice after vaccination with a soluble protein antigen entrapped in liposomes: a model study

EG7-OVA cells are mouse thymoma EL4 cells stably transfected with the complementary DNA of chicken ovalbumin (OVA) and thus express OVA epitopes as a unique antigen. Cytotoxic T lymphocytes specific to OVA can be elicited by immunization of mice with OVA osmotically loaded into syngeneic splenocytes or entrapped in liposomes. Cytotoxic T lymphocytes thus induced can specifically cytolyse the EG7-OVA cells in vitro in an antigen-specific and major histocompatibility complex-restricted manner. In the present study, we have examined in this model system whether immunization with liposomal OVA can protect mice against tumors induced by EG7-OVA cells. Vaccination with OVA either entrapped in liposomes or osmotically loaded in the syngeneic splenocytes prolonged the survival of mice which had been challenged with EG7-OVA cells, but not those mice challenged with the parent EL4 cells. The antitumor effect was attributed to the induced OVA-specific cytotoxic T lymphocyte activity, since other forms of acquired immunity such as interaction of tumor cells with specific antibody could not be detected. Our results demonstrate that immunization with antigen incorporated in liposomes could be a useful means of inducing a protective antitumor response.

[Purification of the ninth component of human complement (C9)]

A large amount of human C9 was purified from plasma by the following procedures: 1) Polyethylene glycol precipitation; 2) Depletion of plasminogen by passing over an L-lys-sepharose column; 3) DEAE-sephadex A-50 chromatography; and 4) Hydroxylapatite (HA) chromatography. The method of C9 purification was improved by altering the column-elution conditions and by the establishment of a novel method for preparing high-flow-rate HA. As a result, the rate of recovery of C9 was high (28.2%) and no impurities were detected either on gel electrophoretic or immunochemical examination. The hemolytic activity of purified C9 was retained.

Induction of cytotoxic T lymphocytes in vivo with protein antigen entrapped in membranous vehicles

Intravenous administration of APC such as splenocytes loaded with a soluble protein Ag has been shown to prime for an Ag-specific CTL response. It is thought that the APC directly presents loaded Ag in a MHC-restricted manner. However, it is demonstrated in this study that allogeneic splenocytes, MHC-free RBC, and even synthetic lipid vesicles (liposomes) after loading with OVA can elicit an OVA-specific and MHC-restricted CTL response. Biodistribution studies of these Ag-associated vehicles showed that the liver, spleen, and lung were the major organs responsible to scavenge these carriers, suggesting that the monocyte-macrophage system was involved in the Ag presentation for CTL. Depletion of macrophages by a specific macrophage killer, Cl2MDP, containing liposomes, abolished the CTL induction by immunization with OVA Ag carried by these vehicles except the induction by syngeneic splenocytes. Thus, the syngeneic splenocytes present Ag directly to the T cells, but other membranous vehicles carry the Ag to the host APC including macrophages, which then present it to the T cells. These results indicate that formulation of an Ag in membranous/colloidal vehicles may be a way to prime for a CTL response.

Induction of cytotoxic T lymphocytes in vivo with protein antigen entrapped in membranous vehicles

Intravenous administration of APC such as splenocytes loaded with a soluble protein Ag has been shown to prime for an Ag-specific CTL response. It is thought that the APC directly presents loaded Ag in a MHC-restricted manner. However, it is demonstrated in this study that allogeneic splenocytes, MHC-free RBC, and even synthetic lipid vesicles (liposomes) after loading with OVA can elicit an OVA-specific and MHC-restricted CTL response. Biodistribution studies of these Ag-associated vehicles showed that the liver, spleen, and lung were the major organs responsible to scavenge these carriers, suggesting that the monocyte-macrophage system was involved in the Ag presentation for CTL. Depletion of macrophages by a specific macrophage killer, Cl2MDP, containing liposomes, abolished the CTL induction by immunization with OVA Ag carried by these vehicles except the induction by syngeneic splenocytes. Thus, the syngeneic splenocytes present Ag directly to the T cells, but other membranous vehicles carry the Ag to the host APC including macrophages, which then present it to the T cells. These results indicate that formulation of an Ag in membranous/colloidal vehicles may be a way to prime for a CTL response.

In vivo cytotoxic T lymphocyte induction with soluble proteins administered in liposomes

The in vivo induction of a CTL response usually requires that Ag be endogenously synthesized so that appropriate processing can occur. In most of the few examples where successful CTL induction was reported with proteins and peptides, unacceptable adjuvants or means of Ag formulation were used. In the present report, liposomes were used to incorporate the soluble proteins OVA and beta-galactosidase. This simple and convenient to use approach, which requires minimal amounts of Ag, results in priming for a CD8+ CTL response and the establishment of immunologic memory. The liposome approach may not only prove a convenient means of inducing CTL responses in vivo but may also be useful to study the mechanisms of Ag processing.

In vivo cytotoxic T lymphocyte induction with soluble proteins administered in liposomes

The in vivo induction of a CTL response usually requires that Ag be endogenously synthesized so that appropriate processing can occur. In most of the few examples where successful CTL induction was reported with proteins and peptides, unacceptable adjuvants or means of Ag formulation were used. In the present report, liposomes were used to incorporate the soluble proteins OVA and beta-galactosidase. This simple and convenient to use approach, which requires minimal amounts of Ag, results in priming for a CD8+ CTL response and the establishment of immunologic memory. The liposome approach may not only prove a convenient means of inducing CTL responses in vivo but may also be useful to study the mechanisms of Ag processing.

Soluble proteins delivered to dendritic cells via pH-sensitive liposomes induce primary cytotoxic T lymphocyte responses in vitro

Effective immunity to many infectious agents, particularly viruses, requires a CD8+ cytotoxic T lymphocyte (CTL) response. Understanding how to achieve CTL induction with soluble proteins is important for vaccine development since such antigens are usually not processed appropriately to induce CTL. In the present report, we have demonstrated that a potent primary CTL response against a soluble protein can be achieved by delivering antigen in pH-sensitive liposomes to dendritic cells (DC) either in vivo or in vitro. Since the pH-sensitive liposome delivery system is efficient and easy to use, the approach promises to be valuable both in the study of basic mechanisms in antigen processing, and as a practical means of immunization.

[Biotransformation of zearalenone]

The conversion of Zearalenone by some strains of microorganisms was investigated. When the selective strains of Rhodotorula sp., Arthrobacter sp., Saccharomyces sp., and Candida sp. were incubated by shaking or standing at 28 degrees C for 72 h with an alcoholic solution of Zearalenone as the substrate at a concentration of 2-10 mg/ml ethanol (50-100 micrograms/ml medium), it was readily converted to give Zearalenols, consisting either mainly of the alpha-isomer (e.g. 96% in case of Rhodotorula sp. and 84% in case of Arthrobacter sp. as determined by HPLC) or beta-isomer (e.g. 91% and 92% in Saccharomyces sp. and Candida sp., respectively). The structure of the product was confirmed by 13C-NMR, MS and HPLC.

An improved method of loading pH-sensitive liposomes with soluble proteins for class I restricted antigen presentation

We have recently shown that ovalbumin (OVA) entrapped in pH-sensitive liposomes could sensitize mouse thymoma cells for lysis by MHC class I-restricted cytotoxic T lymphocytes (CTL) (Reddy et al. (1991) J. Immunol. Methods, 141, 157-163). The present studies were designed to optimize the antigen delivery system. A simple freeze-thaw method was developed to load OVA into pH-sensitive liposomes, and the protocol was optimized in terms of the choice of buffer, pH and ionic strength of the medium, lipid composition, lipid and OVA concentrations and the number of freeze-thaw cycles. Under optimized conditions, approximately 25% of OVA could be entrapped in pH-sensitive liposomes at 172 micrograms protein/mg lipid. This compares to only about 5% entrapment (70 micrograms protein/mg lipid) using the previous method. OVA loaded to pH-sensitive liposomes using the improved method led to a sensitive measure of CTL activity. The approach promises to be suitable to measure CTL against less available soluble antigens such as viral proteins.

Chemical Imaging of Surfaces with the Scanning Electrochemical Microscope

Scanning electrochemical microscopy is a scanning probe technique that is based on faradaic current changes as a small electrode is moved across the surface of a sample. The images obtained depend on the sample topography and surface reactivity. The response of the scanning electrochemical microscope is sensitive to the presence of conducting and electroactive species, which makes it useful for imaging heterogeneous surfaces. The principles and instrumentation used to obtain images and surface reaction-kinetic information are discussed, and examples of applications to the study of electrodes, minerals, and biological samples are given.

pH sensitive liposomes provide an efficient means of sensitizing target cells to class I restricted CTL recognition of a soluble protein

Exogenous antigens are normally endocytosed and enter the class II pathway of processing and presentation. It had been shown earlier that soluble antigen could be introduced into the class I pathway of processing and presentation by osmotic loading. In this report, we have demonstrated that OVA containing liposomes that destabilize on exposure to low pH, referred to as pH sensitive liposomes, could sensitize target cells to lysis by class I MHC-restricted OVA-specific CTL. However, OVA-containing pH insensitive liposomes, native OVA, or OVA subjected to the same protocol as was used to make the liposomes, failed to sensitize targets to OVA-specific CTL lysis. The pH sensitive liposomal approach was less toxic and more efficient (about 20-fold) in delivering than the osmotic loading approach. The pH liposome approach may prove valuable to study CTL recognition characteristics of less available proteins such as viral proteins.

1-GHz repetition-rate frequency-modulation mode-locked neodymium lasers at 1.3 microm

We report on high-repetition-rate frequency-modulation mode locking of all-solid-state neodymium lasers operating at a 1.3-microm wavelength. At a repetition rate of 1 GHz, pulses of 12- and 8-ps durations with average powers of 162 and 240 mW have been obtained for 3-W diode-laser-pumped Nd:YAG and Nd:YLF lasers, respectively. Driven relaxation oscillations of a frequency-modulation mode-locked cw laser are also described.

[Gas chromatograms of fatty acids from Rickettsia and their similarities]

Fatty acid compositions of 7 strains of Rickettsia were analyzed by a on-line GC/MS system. These strains were R. prowazekii E, R. conorii Simko, R. rickettsii R, R. sibirica Barbash and 246, R. sinkiangensis Jinghe, and R. heilungkiangensis 54. The samples were purified by means of the concentrated salt-ether method. There were about 50 peaks in the fatty acid profiles, and 16 of these peaks were determined, i.e. C22:0, C19:0, C18:0, C18:1, C18:2, C17:0, C16:0, C16:1, 3-OH-C14:0, C15:0, C14:0, C13:0, 2-OH-C12:0, C12:0, 2-OH-C10:0, and C11:0. The major fatty acids were the saturated straight chain acids (e.g. C16:0, C18:0, C14:0) and the unsaturated straight chain acids (e.g. C18:1, C18:2, C16:1). Similarities of fatty acid profiles of tested strains were discriminated by the improved Kulik-Vincent method. The result showed that the KV's coefficient of strains Jinghe and 246 was 97.0%, and the KV's coefficient of strains 54 and the others was 81.6-94.6%.

Genetic aspects of antibiotic induced deafness: mitochondrial inheritance

Analysis of 36 pedigrees with a positive family history of aminoglycoside antibiotic induced deafness, ascertained in a population of 483,611 in Zhabei District in Shanghai, showed that the susceptibility to antibiotic ototoxicity was transmitted by females exclusively, indicating mitochondrial inheritance. Reanalysis of 18 other published pedigrees confirmed this conclusion.

High molecular weight kininogen inhibits thrombin-induced platelet aggregation and cleavage of aggregin by inhibiting binding of thrombin to platelets

In this study we show that high molecular weight kininogen (HK) inhibited alpha-thrombin-induced aggregation of human platelets in a dose-dependent manner with complete inhibition occurring at plasma concentration (0.67 mumol/L) of HK. HK (0.67 mumol/L) also completely inhibited thrombin-induced cleavage of aggregin (Mr = 100 Kd), a surface membrane protein that mediates adenosine diphosphate (ADP)-induced shape change, aggregation, and fibrinogen binding. The inhibition of HK was specific for alpha- and gamma-thrombin-induced platelet aggregation, because HK did not inhibit platelet aggregation induced by ADP, collagen, calcium ionophore (A23187), phorbol myristate acetate (PMA), PMA + A23187, or 9,11-methano derivative of prostaglandin H2 (U46619). These effects were explained by the ability of HK, at physiologic concentration, to completely inhibit binding of 125I-alpha-thrombin to washed platelets. As a result of this action of HK, this plasma protein also completely inhibited thrombin-induced secretion of adenosine triphosphate, blocked intracellular rise in Ca2+ in platelets exposed to alpha- and gamma-thrombin, inhibited thrombin-induced platelet shape change, and blocked the ability of thrombin to antagonize the increase in intracellular cyclic adenosine monophosphate (cAMP) levels induced by iloprost. Because elevation of cAMP is known to inhibit binding of thrombin to platelets, we established that HK did not increase the intracellular concentration of platelet cAMP. Finally, HK did not inhibit enzymatic activity of thrombin. To study the role of HK in the plasma environment, we used gamma-thrombin to avoid fibrin formation by alpha-thrombin. Platelet aggregation induced by gamma-thrombin was also inhibited by HK in a dose-dependent manner. The EC50 (concentration to produce 50% of the maximum rate of aggregation) of gamma-thrombin for washed platelets was 7 nmol/L and increased to 102 nmol/L when platelets were suspended in normal human plasma. The EC50 for platelet aggregation induced by alpha-thrombin in plasma deficient in total kininogen was 40 nmol/L. When supplemented with HK at plasma concentration (0.67 mumol/L), the EC50 increased to 90 nmol/L, a value similar to that for normal human plasma. These results indicate that (1) HK inhibits thrombin-induced platelet aggregation and cleavage of aggregin by inhibiting binding of thrombin to platelets; (2) HK is a specific inhibitor of platelet aggregation induced by alpha- and gamma-thrombin; and (3) HK plays a role in modulating platelet aggregation stimulated by alpha-thrombin in plasma.

Frequency stabilization of a diode-laser-pumped microchip Nd:YAG laser at 1.3 microm

We report the active frequency stabilization of a diode-pumped microchip Nd:YAG laser using a frequency-modulation sideband locking technique. The novel aspect of this scheme is that the piezo-mounted output coupler acts as both the frequency modulator and the frequency-correcting element. When the laser is locked to a reference cavity of 300-MHz free spectral range and 5-MHz linewidth, the laser frequency stability is found to be 88 kHz relative to the cavity.

[Analysis of cellular fatty acids of Enterobacteria species by gas chromatography-mass spectrometry]

Cellular fatty acid compositions of 15 Enterobacteria were analyzed by gas chromatography-mass spectrometry(GC-MS). About 30 fatty acids were detected in chromatograms, and 13 of them were chemically identified, e.i. C11:0, C12:0, C13:0, C14:0, C15:0, 2OH-C14:0, 3OH-C14:0, C16:1, C16:0, aC17:0, delta C17:0, C18:1 and C18:0. The major cellular fatty acids in all fifteen species were C16:0, C18:1, C15:0, C14:0, C16:1, C13:0, 3OH-C14:0 and C18:0. The cellular fatty acids of Enterobacteria species were characterized by normal straight-chain saturated acids and monounsaturated acids, of which the most abundant fatty acid was C16:0. 3OH-C14:0 was found in all strains of Enterobacteria, whereas 2OH-C14:0 was only found in strains of Serratia species. Other unknown compositions also would have been certain characteristics for bacteria. The present paper would provide some of useful reference data for chemotaxonomy and molecular microbiology of Enterobacteria.

Measuring the wavelength dependence of magnetooptical Kerr (or Faraday) rotation and ellipticity: a technique

A technique is proposed that allows accurate determination of the magnetooptic rotation and ellipticity angles. This method requires only a few standard optical elements and is expected to be effective over a relatively wide range of wavelengths.

[Study on the discrimination of bacteria by gas chromatographic profiles of cellular monosaccharides]

A procedure for obtaining gas chromatographic (GC) profiles of bacterial cellular monosaccharides was described. Some of the unknown component peaks in these profiles were identified. And, based on the complete linkage cluster analysis with the Euclidean distance coefficient, the interpretation of the resulting cellular monosaccharides of bacteria were performed by mini-computer. By means of this method, the discrimination of 5 species (24 strains) of aerobic endospore-forming bacteria. The results showed that there were defined differences between the profiles of cellular monosaccharides of B. anthracis and B. cereus. This procedure has provided a useful method for the classification and identification of microorganisms, for their physiological and biochemical studies, and for studies on their subcellular components.

[Relation of Fourier transform infrared spectroscopic characteristics of pilose antler and its traditional quality grade]

The relationship between FTIR characteristics of Pilose Antler and its traditional quality grade was studied and a rule governing its quality value "Z" was found. We have thus advanced a new objective target for preparing Pilose Antler tablets and powder.

Non-classical antiestrogenic actions of dexamethasone in variant MCF-7 human breast cancer cells in culture

The aim of this work was to determine whether dexamethasone (Dex), a synthetic glucocorticoid, counteracts the stimulatory effects of estradiol (E2) on MCF-7 cells. We have shown that Dex inhibits in a dose-dependent fashion the estradiol-stimulated cell proliferation. This inhibition (ID50 congruent to 5-10 nM), which is complete at 100 nM Dex, is prevented by the antiglucocorticoid RU 486 and is clearly different from that found with trans-4-OH-tamoxifen because the inhibition due to a fixed concentration of Dex is not abolished by a high concentration of estradiol. This inhibitory effect displays some degree of specificity. Progesterone and the progestins R 5020 and ORG 2058 are without effect and Dex does not alter the triiodo-L-thyronine-stimulated cell growth. To characterize further the antiestrogenic action of Dex, the effects of this drug on specific responses to estradiol were studied. (1) Among the positive responses to estradiol two are prevented by Dex (the increase of concentration of progestin receptors and that of immunoreactive insulin-like growth factor I, IR-IGF-I, in conditioned medium) and two are insensitive to Dex (the enhancement of the secretion of 52,000 and 160,000 Mr proteins). (2) A negative response to estradiol (the down-regulation of estrogen receptor) is not prevented but rather accentuated by Dex. Thus, Dex counteracts the stimulatory effects of estradiol on the proliferation of MCF-7 cell variants characterized by progestin insensitivity. This non-classical antiestrogenic effect could be due in part to the attenuation of the E2-induced IR-IGF-I secretion and, less probably, to the accentuation of the down-regulation of E2 receptors. It could account for certain therapeutic and/or side effects of glucocorticoids on estrogen target cells.

Characterization of plasma-stabilized liposomes composed of dioleoylphosphatidylethanolamine and oleic acid [published errtum appears in Biochem Biophys Res Commun 1989 Sep 29;163(3):1539]

We have previously reported that small unilamellar liposomes (d less than or equal to 200 nm) composed of dioleoylphosphatidylethanolamine and oleic acid can be stabilized by incubating with normal human plasma (Liu and Huang, Biochemistry 1989, in press). The stabilized liposomes were very stable even under relatively harsh conditions such as extreme pH, high salt and trypsin treatment. Fluorescence depolarization of diphenylhexatriene showed that the stabilized liposome had a high microviscosity in the lipid core, which did not decrease even after the majority of proteins were removed by trypsin. These data suggest that plasma proteins inserted into the lipid bilayer are probably responsible for the stabilization activity. After i.v. injection into mouse, stabilized liposomes showed a relatively low affinity to liver and spleen as compared to a conventional liposome composition.

Prevalence and genetic aspects of deaf mutism in Shanghai

Two hundred and eighty-five cases of congenital deaf mutism were ascertained in a population of 483,611 in Zhabei District in Shanghai. The prevalence was 0.059% (1:1697). Inherited cases accounted for 84.83% of all cases. The mode of inheritance was autosomal recessive with complete penetrance and heterogeneity (consisting of at least five different loci). The fitness was 77.63%, the coefficient of selection was 0.2237, the mutation rate was 1.119 x 10(-4) mutation/gamete, and no heterozygote advantage was proven.

Direct evidence for the interaction of the nucleotide affinity analog 5'-p-fluorosulfonylbenzoyl adenosine with a platelet ADP receptor

Previous reports have indicated that the nucleotide affinity analog 5'-p-fluorosulfonylbenzoyl adenosine (FSBA) at concentrations between 40 and 100 mumol/L and at times greater than 20 minutes covalently modifies a single protein component on the external platelet membrane surface and that adenosine diphosphate (ADP) protects against this reaction. That this protein is an ADP receptor linked to platelet activation is shown by FSBA inhibition of ADP-mediated platelet shape change, aggregation, and fibrinogen receptor exposure. In this report, further evidence for the interaction of FSBA with the ADP receptor on platelets is provided by the observation that FSBA at high concentrations (100 to 500 mumol/L) behaves as a weak agonist to produce platelet shape change within one minute as detected by spectroscopic assay and scanning electron microscopy with concomitant phosphorylation of the light chain of platelet myosin. The specificity of FSBA as an agonist is demonstrated by inhibition of FSBA-induced shape change by ATP and the covalent incorporation of SBA as well as the failure of 5'-fluorosulfonylbenozoyl guanosine (FSBG) to cause shape change. In contrast, incubation of platelets with low concentrations of [3H]-FSBA (40 mol/L) is not associated with stimulation of platelet shape change or myosin light chain phosphorylation.