Ultraviolet photometer observations of the saturnian system.

Several interesting cloud and atmospheric features of the Saturn system have been observed by the long-wavelength channel of the two-channel ultraviolet photometer aboard the Pioneer Saturn spacecraft. Reported are observations of the most obvious features, including a Titan-associated cloud, a ring cloud, and the variation of atmospheric emission across Saturn's disk. The long-wavelength data for Titan suggest that a cloud of atomic hydrogen extends at least 5 Saturn radii along its orbit and about 1.5 Saturn radii vertically. A ring cloud, thought to be atomic hydrogen, has also been observed by the long-wavelength channel of the photometer; it shows significant enhancement in the vicinity of the B ring. Finally, spatially resolved observations of Saturn's disk show significant latitudinal variation. Possible explanations of the variation include aurora or limb brightening.

Bladder repair following iatrogenic cystotomy in irradiated small capacity bladders.

During laparotomy in a previously irradiated and operated pelvis, incidental cystotomies can occur and a tension-free, watertight, two- or three-layer closure of the bladder may be impossible. We herein report two cases of iatrogenic defects of the bladders in post-irradiated pelvises and compare the two different methods of bladder repair employed - an ileal augmentation segment used in the first case and bovine pericardial graft used in the second. Successful closures of the bladder defects were achieved in both cases. Native irradiated bowel and bovine pericardium can be useful substitutes in situations involving bladder defects in a previously irradiated pelvis. The advantages and disadvantages of the two approaches are also herein discussed.

Inhibition of myeloid differentiation by inhibitors of ADP-ribosylation.

Inhibitors of ADP-ribosylation inhibited the myeloid differentiation of murine myelomonocytic leukemia, WEHI-3BD+ cells induced by granulocyte colony-stimulating factor. Benzamide, at 2.0 mM, inhibited 50% of the WEHI-3BD+ cell differentiation but had no significant effect on the proliferation. However, benzylaminododecylguanine hydrochloride and p-methoxylbenzylaminodecamethylene guanidine sulfate at 2.0 and 2.2 microM, respectively, inhibited 50% of proliferation but had no effect at all on differentiation. The differential effects of inhibitors provide a model to study the role of ADP-ribosylation in myeloid differentiation.

Differentiation of cultured promyelocytic leukemia cells (HL-60) induced by endotoxin-treated human lung conditioned medium.

Serum-free conditioned medium prepared from endotoxin-treated human lung tissue contains potent differentiation activity (DA) which induces the differentiation of human promyelocytic leukemia cells (HL-60) to mature functioning granulocytes and macrophages. Upon fractionation, the DA can be separated from colony-stimulating factors (CSFs). The estimated molecular weight of DA is 23,000 d which is similar to CSF-II but is much smaller than CSF-I (50,000 d). The isoelectric point (PI) value obtained from preparative isoelectrofocusing is 5.2, which is higher than CSF-I of 4.1-4.8 but lower than CSF-II of 5.6. Using isopropanol as solvent and trifluoroacetic acid (0.2%) as ion-pair, the DA is eluted at 37% isopropanol from the C-3 column in comparison to 30% for CSF-II and 34% for CSF-I.

Effect of topical ascorbic acid on free radical tissue damage and inflammatory cell influx in the cornea after excimer laser corneal surgery.

OBJECTIVE: To evaluate the effect of topical ascorbic acid on oxygen free radical tissue damage and the inflammatory cell influx in the cornea after excimer laser keratectomy. METHODS: Five New Zealand white rabbits underwent bilateral phototherapeutic keratectomy with the 193-nm argon fluoride excimer laser. Following treatment, the right eye of each rabbit was treated with 10% ascorbic acid every 3 hours for 24 hours. The left eyes served as controls. After 24 hours, all animals were killed and their corneas were trephined and processed. Sections were stained with fast blue B and with hematoxylin-eosin. Oxidative tissue damage in the form of lipid peroxidation was detected by fluorescent peroxidized carbonyl compounds using a confocal laser scanning microscope. The quantity of these compounds was determined using the National Institutes of Health digital image analysis system. Statistical comparisons of lipid peroxidation and polymorphonuclear cell count between the ascorbic acid groups and the controls were performed using the Student t test. RESULTS: Lipid peroxidation and polymorphonuclear cell counts were significantly decreased in the superficial cornea of ascorbic acid-treated eyes compared with control eyes (P <.03 and <.02, respectively). CONCLUSIONS: Topical ascorbic acid application decreased oxygen radical tissue damage following excimer keratectomy; moreover, topical application of ascorbic acid was shown to reduce the acute inflammatory reaction efficiently. This suggests that topical ascorbic acid could be considered a complementary treatment in the pharmacological modulation after excimer laser corneal surgery. CLINICAL RELEVANCE: Corneal opacity may complicate excimer keratectomy. The use of an antioxidant to reduce tissue damage could help minimize postoperative stromal opacification.

The nucleotide sequence of Schwanniomyces occidentalis alpha-amylase gene.

The nucleotide sequence of the coding and regulatory regions of the alpha-amylase-encoding gene (AMY) of Schwanniomyces occidentalis has been determined. This sequence contained an open reading frame of 512 codons, from which a protein with Mr of 53,723 could be predicted. A putative signal sequence encoding for 25 amino acids was proposed for the 5' end of the open reading frame. Regulatory sequences, such as TATA box, CCAAT box and a signal sequence for polyadenylation and transcription termination could be found in the flanking regions of AMY gene. The deduced amino acid sequence also contained four common conserved regions characteristic of other alpha-amylase proteins.

Refractive keratotomy after photorefractive keratectomy.

BACKGROUND: The current surgical procedures available for the treatment of residual myopia and/or astigmatism after photorefractive keratectomy (PRK) include refractive keratotomy, laser in situ keratomileusis (LASIK), repeat PRK, or photorefractive astigmatic keratectomy (PARK). In this study, we investigate the safety and efficacy of refractive keratotomy for the correction of residual myopia and/or astigmatism after PRK. METHODS: Ten eyes of 9 patients underwent refractive keratotomy after excimer laser photorefractive keratectomy using the Lindstrom nomogram. PRK procedures were performed using the VISX 20/20 system by one surgeon. RESULTS: All eyes except one obtained an uncorrected visual acuity of 20/40 or better. One eye developed significant haze following PRK with myopic astigmatic regression and underwent refractive keratotomy to correct the residual refractive error. This patient was also the only patient who lost 2 lines of spectacle-corrected visual acuity secondary to corneal haze. CONCLUSION: This study demonstrates that refractive keratotomy can reduce residual astigmatism and myopia that may be present following excimer laser photorefractive keratectomy. Our results suggest there is no need to change the refractive keratotomy nomograms for eyes that have previously undergone PRK.

Opiate antagonists and copulatory behavior of male hamsters.

A possible role of endogenous opioids in male copulatory behavior was examined in six experiments which studied the effects of opiate antagonists on the copulatory behavior of male hamsters (Mesocricetus auratus). In Experiment 1, the acute administration of naloxone hydrochloride (4 mg/kg, SC) ten minutes before testing significantly decreased mount frequency, intromission frequency, and ejaculation latency. In Experiment 2 males were tested weekly for three weeks. Half of the males were injected with naloxone ten minutes before each test and half with physiological saline. Naloxone administration reduced mount frequency, and intromission frequency while increasing the postejaculatory interval and the proportion of males displaying behavioral signs of satiety. In Experiment 3 similar effects were obtained following daily administration of naltrexone hydrochloride (10 mg/kg/day SC). In Experiment 4 males were allowed to mate to satiety. Naloxone treated males were more likely to display behavioral signs of satiety during the first ten minutes of these tests. In Experiment 5 it was demonstrated that naloxone administration did not alter the duration of insertion during either intromissions or ejaculations. In Experiment 6 the administration of naloxone did not facilitate the display of copulatory behavior by sexually inactive males. Overall the results are consistent with the hypothesis that opiate antagonists alter male copulatory behavior by enhancing the impact of stimuli occurring during the sexual interaction.

Genomic subtraction in combination with PCR for enrichment of Listeria monocytogenes-specific sequences.

Genomic DNA from Listeria innocua and Listeria ivanovii was used in subtractive hybridization with DNA from Listeria monocytogenes involving two amplification strategies. Subtraction was accomplished by labelling the subtracting DNA with biotin and removal after liquid hybridization with tester DNA (L. monocytogenes) by reaction with streptavidin and phenol extraction. In one strategy, L. monocytogenes DNA was poly(A)-tailed with terminal transferase and amplified asymmetrically after subtraction. In another procedure, adapters ligated to the target DNA allowed symmetrical amplification after subtraction using an adapter-specific primer; in both amplifications, the amplified products were labelled with biotin-modified dUTP. Southern hybridization of the amplified/subtracted probes with tester- and subtractor-related strains demonstrated numerous L. monocytogenes-specific sequences. The genome-subtracted mixed probe identified 7 RFLP patterns among 13 strains of L. monocytogenes representing 11 L. monocytogenes serovars. Southern blot analysis demonstrated that the subtracted probe cross-hybridized to two bands among L. welshimeri strains but had little or no hybridization with five other species of Listeria including L. innocua, L. ivanovii, L. seeligeri, L. grayi, and L. murrayi. These data demonstrate that genomic subtraction via subtractive hybridization is a powerful method to enrich for specie-specific sequences in L. monocytogenes; the enriched sequences in the subtracted probe may be useful for typing L. monocytogenes strains by specific RFLP patterns or for cloning L. monocytogenes-specific sequences.

Factors influencing the detection and enumeration of Escherichia coli O157:H7 on alfalfa seeds.

Isolating Escherichia coli O157:H7 from batches of alfalfa seeds used to produce sprouts implicated in human illness has been difficult, perhaps due to nonhomogenous and very low-level contamination and inaccessibility of the pathogen entrapped in protected areas of the seed coat. We evaluated the effectiveness of various treatments in releasing E. coli O157:H7 from seeds. The influence of homogenization (blending or stomaching for 1 or 2 min), rinsing method (shaking for 5 min), soaking time (0. 1, 3, 6, or 15 h), soaking temperature (4 or 21 degrees C), and the addition of surfactants (0.1%, 0.5%, or 1.0% Tween 80 or Span 20) to rinse water was determined. Blending or stomaching for 1 or 2 min, and soaking for 1 h or longer at 4 or 21 degrees C, respectively, resulted in maximum release of E. coli O157:H7 from seeds. Soaking seeds at 37 degrees C for 15 h increased cell populations of E. coli O157:H7 by approximately 3.6 log10 CFU/g, likely due to bacterial growth. The maximum number of cells released from seeds by rinse water containing 1.0% Span 20 was at 21 degrees C, whereas at 37 degrees C, 0.1% or 0.5% Tween 80 was more effective. Detection of E. coli O157:H7 on seeds stored at 37 degrees C for up to 13 weeks and on sprouts derived from these seeds was compared. E. coli O157:H7 inoculated on seeds at 2.0 log10 CFU/g was detected after storage of seeds for up to 8 weeks at 37 degrees C and in sprouts produced from the seeds. The pathogen was not detected on seeds stored for 13 weeks at 37 degrees C and was not isolated from sprouts produced from these seeds. Identifying seed treatment methods that enhance removal of E. coli O157:H7 from alfalfa seeds can aid the isolation and enumeration of the pathogen on seeds. With a combination of optimal conditions for detecting the pathogen, i.e. soaking seeds for 1 h and pummeling seeds for 1 min, an enrichment step in modified tryptic soy broth (TSB), and the use of immunomagnetic beads for separation of E. coli O157:H7 cells, E. coli O157:H7 was detected in alfalfa seeds incubated at 37 degrees C for up to 8 weeks as effectively as in sprouts produced from the seeds.

Chlorine inactivation of Escherichia coli O157:H7 in water.

Six human isolates of Escherichia coli O157:H7 and E. coli (ATCC 11229) were used to determine the concentrations of free chlorine and exposure times required for inactivation. Free chlorine concentrations of 0.25, 0.5, 1.0, and 2.0 ppm at 23 degrees C were evaluated, with sampling times at 0, 0.5, 1.0, and 2.0 min. Results revealed that five of six E. coli O157:H7 isolates and the E. coli control strain were highly susceptible to chlorine, with >7 log10 CFU/ml reduction of each of these strains by 0.25 ppm free chlorine within 1 min. However, comparatively, one of the seven strains was unusually tolerant to chlorine at 23 degrees C for 1 min, with a 4-, 5.5-, 5.8-, and >5.8-log CFU/ml reduction at free chlorine concentrations (ppm) of 0.25, 0.5, 1.0, and 2.0. respectively. Based on these studies most isolates of E. coli O157:H7 have no unusual tolerance to chlorine; however, one strain was exceptional in being recovered after 1-min of exposure of 10(7) CFU/ml to 2.0 ppm of free chlorine. This isolate may be a useful reference strain for future studies on chlorine tolerance of E. coli O157:H7.

Fate of Escherichia coli O157:H7 in coleslaw during storage.

An outbreak of Escherichia coli O157:H7 infection associated with the consumption of coleslaw in several units of a restaurant chain prompted a study to determine the fate of the pathogen in two commercial coleslaw preparations (pH 4.3 and 4.5) held at 4, 11, and 21 degrees C for 3 days. At an initial population of 5.3 log10 CFU/g of coleslaw, E. coli O157:H7 did not grow in either coleslaw stored at the three temperatures. Rather, the population of E. coli O157:H7 decreased by 0.1 to 0.5 log10 CFU/g within 3 days. The greatest reduction (0.4 and 0.5 log10 CFU/g) in population occurred at 21 degrees C, whereas only slight decreases (0.1 to 0.2 log10 CFU/g) occurred at 4 and 11 degrees C. A pH of 4.3 to 4.5 of coleslaw had little effect on reducing E. coli O157:H7 populations. Results suggest that the tolerance of E. coli O157:H7 to acid pH, not temperature abuse, is a major factor influencing the pathogen's fate in restaurant-prepared coleslaw.

Fate of Shigella sonnei on parsley and methods of disinfection.

Outbreaks of shigellosis associated with chopped parsley used as a garnish for foods occurred in four states in the United States and in two Canadian provinces in 1998. This prompted a study to determine survival and growth characteristics of Shigella sonnei inoculated onto raw parsley. Two inoculum levels (approximately 10(3) and 10(6) CFU/g) were applied to parsley leaves, portions of which were then chopped. Inoculated whole and chopped parsley leaves were held at 4 degrees C or 21 degrees C for up to 14 days. Initial populations of the organism on chopped parsley receiving high or low levels of inoculum increased by approximately 3 log10 CFU/g, within 1 day at 21 degrees C. Populations of S. sonnei on inoculated chopped or whole parsley leaves held at 4 degrees C decreased by 2.5 to 3.0 log10 CFU/g during a 14-day storage period. The pathogen multiplied, without a lag phase, on inoculated (2.72 log10 CFU/g) chopped parsley held at 21 degrees C, exceeding 6 log10 CFU/g within 24 h. Treatment of inoculated whole parsley leaves with vinegar containing 5.2% (vol/vol) acetic acid or 200 ppm free chlorine for 5 min at 21 degrees C reduced the population of S. sonnei by more than 6 log10 CFU/g, whereas treatment with vinegar containing 7.6% acetic acid or 250 ppm free chlorine reduced initial populations of 7.07 and 7.26 log10 CFU/g, respectively, to undetectable levels (<0.6 log10 CFU/g). These studies revealed that S. sonnei can grow rapidly on chopped parsley held at ambient temperature and remain viable for at least 14 days at 4 degrees C. Treatment of contaminated parsley with vinegar or chlorinated water offers a simple method to reduce markedly or eliminate the pathogen in food-service or home settings.

[Correlation between synaptic protein phosphorylation in hippocampi and shuttle box avoidance behavior].

The present investigation was undertaken to detect whether protein phosphorylation levels of hippocampal synaptosomes in mice trained on shuttle box avoidance task would show some changes. The synaptosomes were prepared at different times after the conclusion of training and labelled with gamma-32P-ATP for in vitro determination. The results are as follows: (1) No significant differences were found in the phosphorylation of synaptosomal proteins in different brain areas in normal mice before training. (2) Immediately after the conclusion of shuttle box avoidance task there appears a correlation between protein phosphorylation levels in hippocampal synaptosomes and the degree of success of training. (3) 24 h after the completion of training the above relationship is more significant, and protein phosphorylation levels of right hippocampus in Good Score Group is markedly higher than that of left one, but in the Inferior Score Group, the left-right difference is reverse. The formation of such asymmetry in protein phosphorylation in hippocampi is unknown. These data indicate that the synaptic protein phosphorylation in hippocampi might be a molecular mechanism of acquisition.

[Regulation of ACTH4-9 analogue on the Ca2+ level of mouse hippocampal synaptosomes].

The effect of ACTH4-9 analogue Org2766 on the [Ca2+]i level of mouse hippocampal synaptosomes was studied. Synaptosomal free calcium concentration ([Ca2+]i) and 45Ca2+ uptake were measured respectively by spex cation measurement system and Beckman LS-9800 liquid scintillation spectrometer. Low dose of Org2766 did not change synaptosomal [Ca2+]i level, but decreased 45Ca2+ uptake. High dose of Org2766 increased [Ca2+]i without affecting 45Ca2+ uptake. Low dose of Org2766 inhibited the anisomysin-induced increase of synaptosomal [Ca2+]i while high dose had no effect. These results suggest that the regulation of Org2766 on hippocampal synaptosomal Ca2+ level may be achieved by inhibiting the Ca2+ influx and increasing the release of synaptosomal calcium pool.

[Correlation between the age-related memory impairment and the level of free Ca(2+) in brain synaptosomes].

In this study, We investigated the changes in the ability of learning-memory of 12-month- and 18-month-old mice, and the intrasynaptosomal Ca(2+) levels of some mouse brain areas (hippocampus, cerebral cortex, corpus quadrigem and cerebellum) on the basis of our last behavior observation and biochemistry detection. Meanwhile, the intrasynaptosomal Ca(2+) levels of the four brain areas were compared between the mice of impaired and good memory. The main results are as follows. With the increase of age, the ability of learning-memory of mice decreased significantly; and the concentration of the intrasynaptosomal free Ca(2+) (i) in mouse brain areas (except for cerebral cortex) increased markedly, especially in the memory-impaired mice. The results suggest that age-related memory impairment may be associated with the overloading of intrasynaptosomal free Ca(2+) (i).

[Correlation between ability of learning-memory and synaptosomal free [Ca2+]i in mice of different age].

In the present investigation, the behavior of learning and memory of 1-month and 6-month-old mice was studied by using Y-maze and one-trial passive avoidance response device. The synaptosomal free [Ca2+]i of four main brain regions (Hippocampus, Cerebral cortex, Cerebellum, Tectum of midbrain) of these mice were measured by fluorescent probe Ca2+ indicator Fura-2 and an AR-CM-MIC cation measurement system. The results showed that, in comparison with 1-month-old mice, the ability of discrimination learning and memory of 6-month-old ones were attenuated, and the synaptosomal free [Ca2+]i of hippocampus was increased.

[Improving effect of NGF by intrahippocampal injection on aging-related memory impairment].

AIM: To study the improving effect of NGF (nerve growth factor) on aging-related memory impairment and its possible mechanism of action. METHODS: After direct intrahippocampal injection of NGF, the spontaneous behavior and the memory retention of aging mice were observed using open field and one-trial passive avoidance test. At the same time, the free [Ca2+] and protein synthesis in hippocampal synaptosomes were measured in vitro by using fluorescence indicator Fura-2/AM and 3H-Leu respectively. RESULTS: Compared with the control, NGF was shown to increase significantly the spontaneous behavior and explorative response in the open field, and improve remarkably the memory consolidation of old mice (P < 0.05). NGF decreased notably the intrasynaptosomal free [Ca2+] in hippocampus. Meanwhile, the incorporation of 3H-Leu into the synaptosomal proteins of hippocampus increased significantly. CONCLUSION: NGF showed an improvement effect against the aging-related memory impairment. A decrease of intrasynaptosomal free [Ca2+] and an increase in protein synthesis may be involved in this effect.

[Regulation of NGF on intra-synaptosomal free [Ca2+]i in mouse brain].

In the present study, the influence of direct intrahippocampal injection of NGF (nerve growth factor) on synaptosomal free [Ca2+]i in 1-month-old and 18-month-old mice was observed. The regulation of NGF on synaptosomal free [Ca2+]i in vitro was also investigated. The synaptosomal free [Ca2+]i in the main brain regions (cerebral cortex, hippocampus, cerebellum, diencephalon) of these mice was measured by fluorescent probe Fura-2 of Ca2+ indicator and an AR-CM-MIC cation measurement system. The results are as follows: (1) NGF showed no detectable effect on hippocampal intrasynaptosomal free [Ca2+]i in 1-month-old mice, but appropriate dose of NGF was shown to markedly reduce [Ca2+]i in 18-month-old mice. (2) Under the condition of low [Ca2+]i level caused by the drug, NGF was found to increase [Ca2+]i; conversely, was reduced [Ca2+]i when intracellular Ca2+ was overloaded. These results suggest that NGF has dual regulation on Ca2+ level in brain and this might be an important mechanism for its action in improving memory lesion, in aged person.

[Effect of DGAVP and Org2766 on intracellular free Ca2+ concentration in dissociated brain cells].

Intracellular free calcium concentration ([Ca2+]i) was measured with Fura-2 in freshly dissociated brain cells isolated from newborn (1-2 day) mouse pups using AR-CM-MIC cation measurement system, and the effects of DGAVP and Org2766 on the changes in [Ca2+]i induced by the protein synthesis inhibitor anisomycin (ANI) were studied. The results indicate that anisomycin caused dose-dependent increases in [Ca2+]i; and DGAVP itself showed no significant effect on [Ca2+]i, but an appropriate dose of DGAVP antagonized the increases induced by the selective dose-range of ANI, suggesting that the antagonism of ANI-induced inhibition of protein synthesis by DGAVP was likely achieved by preventing ANI from increasing [Ca2+]i, but this mechanism did not apply to the other neuropeptide Org2766. Therefore, we suppose that the mechanism of the two neuropeptides are different in terms of their effect on intracellular free calcium concentration.