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.

Effects of adenosine 3',5'-cyclic monophosphate, forskolin, and cholera toxin on hormone production in human term placental cells

Trophoblast cells from human term placenta in monolayer culture were used to investigate the role of adenosine 3',5'-cyclic monophosphate in the production of human chorionic gonadotropin and estradiol-17 beta. The intracellular concentration of adenosine 3',5'-cyclic monophosphate was elevated by (1) addition of an adenosine 3',5'-cyclic monophosphate analogue, 8-bromoadenosine 3',5'-cyclic monophosphate, (2) inhibition of the hydrolysis of Gs-GTP complex by cholera toxin, and (3) direct stimulation of adenylate cyclase with forskolin. Addition of 2 mmol/L of 8-bromoadenosine 3',5'-cyclic monophosphate markedly increased the accumulation of human chorionic gonadotropin in the culture medium on days 2, 3, and 4 of treatment. Likewise, addition of cholera toxin (0.2 microgram/ml) or forskolin (50 mumol/L) also enhanced human chorionic gonadotropin production. On the other hand, the production of estradiol-17 beta was significantly inhibited by 8-bromoadenosine 3',5'-cyclic monophosphate, at the same time that human chorionic gonadotropin production was enhanced in the same experiments. These results further support a differential role of adenosine 3',5'-cyclic monophosphate on human chorionic gonadotropin and estradiol-17 beta production in the human term placenta.

Serotonin turnover in raphe neurons transplanted into rat hippocampus

Injections of the neurotoxin, 5,7-dihydroxytryptamine, into rostral raphe nuclei in rats reduced serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in hippocampus to 35-50% of normal levels but only reduced 5-HT synthesis and catabolism by 20-35%. The small reduction in 5-HT metabolism as compared to depletion of 5-HT suggests that 5-HT turnover was increased in nerve terminals that survived the neurotoxin lesion. Transplantation of rat fetal raphe cells into the 5-HT-denervated hippocampus restored 5-HT and 5-HIAA levels and 5-HT synthesis to 125-150% of normal. This demonstrates that transplantation of fetal raphe tissue can restore metabolism to normal levels in the 5-HT denervated hippocampus.