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.

Molecular dynamics study of the structures and dynamics of the iodine molecules confined in AlPO(4)-11 crystals.

Structural and dynamical properties of iodine molecules incorporated in one-dimensional elliptic channels of AlPO(4)-11 (AEL) crystals were studied by means of molecular dynamics (MD) simulations. It was found that the iodine molecules in the AEL channels are restricted in the (101) planes with only two favorite orientations: lying along the channels and standing along the major axes of the ellipses, which are well consistent with the experimental observations. In addition, the iodine structures are largely dependent on the loading level: with the increase of loading, the iodine specimens change their structures accordingly from isolated molecules as in the gas phase to single molecular chains and molecular ribbon sheets. The molecular ribbon sheets are composed of equally distributed and parallel molecules as in the iodine crystals. The simulation results show that the standing iodine molecules in the AEL channels are well restricted due to both the appropriate size of ellipses and their alternation throughout the channels. They can diffuse along the channels only after overcoming the rotational barriers to become lying molecules, which indicate that the iodine molecules in the ribbon sheets can keep the configurations without rotational and translational motion. The confined iodine molecules with such structures and properties may be used to improve the accuracy of the frequency standards.

Low-density to high-density transition in Ce75Al23Si2 metallic glass.

Using in situ high-pressure x-ray diffraction (XRD), we observed a pressure-induced polyamorphic transition from the low-density amorphous (LDA) state to the high-density amorphous (HDA) state in Ce(75)Al(23)Si(2) metallic glass at about 2 GPa and 300 K. The thermal stabilities of both LDA and HDA metallic glasses were further investigated using in situ high-temperature and high-pressure XRD, which revealed different pressure dependences of the onset crystallization temperature (T(x)) between them with a turning point at about 2 GPa. Compared with Ce(75)Al(25) metallic glass, minor Si doping shifts the onset polyamorphic transition pressure from 1.5 to 2 GPa and obviously stabilizes both LDA and HDA metallic glasses with higher T(x) and changes their slopes dT(x)/dP. The results obtained in this work reveal another polyamorphous metallic glass system by minor alloying (e.g. Si), which could modify the transition pressure and also properties of LDA and HDA metallic glasses. The minor alloying effect reported here is valuable for the development of more polyamorphous metallic glasses, even multicomponent bulk metallic glasses with modified properties, which will trigger more investigations in this field and improve our understanding of polyamorphism and metallic glasses.

Amorphouslike diffraction pattern in solid metallic titanium.

Amorphouslike diffraction patterns of solid elemental titanium have been detected under high pressure and high temperature using in situ energy-dispersive x-ray diffraction and a multianvil press. The onset pressure and the temperature of formation of amorphous titanium is found to be close to the alpha-beta-omega triple point in the P-T phase diagram. Amorphous Ti has been found to be thermally stable up to 1250 degrees C for at least 3 min at some pressures. By analyzing the conditions for producing amorphous elemental Zr and Ti, we observed a multi-phase-point amorphization phenomenon for preparing single-element bulk amorphous metals. The results reported may open a new way to preparing single-element bulk amorphous metals with a high thermal stability.

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.

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.

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.

cAMP attenuates interleukin-1-stimulated macrophage colony-stimulating factor (M-CSF) expression.

Macrophage colony-stimulating factor (M-CSF) is a multifunctional cytokine attributed with key biological functions beyond the first discovered role in promoting proliferation of myeloid cell lineage. The human pancreatic cancer cell line MIA PaCa-2, from which the M-CSF gene was originally cloned, was used to study regulation of M-CSF expression. Expression of M-CSF was inducible by interleukin-1alpha (IL-1alpha), lipopolysaccharide (LPS) and PMA as demonstrated by a biological activity assay, Northern-blot analysis and reverse transcriptase (RT) PCR. Treatment of the cells with forskolin or dibutyryl-cAMP attenuated the expression of M-CSF induced by IL-1alpha or LPS, but not by PMA. Electromobility shift assays showed that IL-1alpha predominantly activated nuclear factor kappaB (NF-kappaB), while PMA preferentially activated activator protein-1 (AP-1). The activation of NF-kappaB, but not AP-1, could be attenuated by cAMP elevation. Relative RT-PCR demonstrated that the expression of a 1.6-kb M-CSF mRNA transcript was more effectively induced by IL-1alpha than a 4.0-kb transcript. By and large the induced expression of both mRNA transcripts could be attenuated by cAMP. M-CSF promoter-driven luciferase reporter-gene assays revealed that cAMP elevation attenuated the IL-1-induced transcription activation of the M-CSF promoter, but it had no effect on PMA-induced transcription. Our findings suggest that cAMP regulates M-CSF gene expression at the transcriptional level and that its inhibitory effect involves NF-kappaB signalling pathway.

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 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).

[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.

Seroprevalence of CMV antibodies in a blood donor population and premature neonates in the south-central Taiwan.

Infection of cytomegalovirus (CMV) via contaminated blood may endanger immunocompromised patients that require transfusion therapy. The aim of this study is to determine the prevalence of CMV antibodies in the blood donor population in Southern-central Taiwan. A total of 1800 consecutive sera, obtained from Tainan Blood Center of Chinese Blood Services Foundation (CBSF), were tested for CMV antibodies by two commercial enzyme immunoassays (EIAs). Of the sera tested, 150 (8.3%) were found to be CMV seronegative. The frequency of CMV seropositivity revealed no significant difference between male and female donors. The frequency of CMV seronegativity showed a stepwise decrease with the increase of donor age. In addition, the prevalence of HBsAg, antibodies to hepatitis C virus (anti-HCV), antibodies to human immunodeficiency viruses type 1 and 2 (anti-HIV 1 + 2) and antibodies to human T-cell lymphotropic viruses type I and II (anti-HTLV I/II) were compared between CMV seropositive and seronegative groups. Our results showed that there was no significant difference in seroprevalence of these markers between CMV seropositive and seronegative groups. Our findings also showed that six out of twenty (30.0%) premature neonates were CMV-seropositive. These premature specimens and those EIA discrepancy samples were confirmed by specific nucleic acid amplification using polymerase chain reaction (PCR). Our results suggest that a program which aims to supply CMV seronegative blood or blood components to the patients, should not solely depend on current antibody screening methods in an area where CMV infection is highly endemic. Amendments such as PCR testing, leukocyte reduction by filtration before transfusion may be more practical.

Cloning, sequencing, and characterization of genomic subtracted sequences from Listeria monocytogenes.

Individual sequences of a genomic subtracted, PCR-amplified, mixed-sequence probe (GS probe) were cloned and sequenced. The GS probe differentiated restriction fragment length polymorphism patterns for Listeria monocytogenes but did not hybridize with members of other bacterial genera. Sequence analysis identified several L. monocytogenes sequences already present in the GenBank database; the putative identities of other sequences were inferred from homology data, and still other sequences did not exhibit significant levels of homology with any GenBank sequences.

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.

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.

[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.

Nitric oxide is involved in the formation of learning and memory in rats: studies using passive avoidance response and Morris water maze task.

The study was designed to test whether blockade of endogenous NO production affects learning and memory formation in rats. The rats received an intracerebroventricular (i.c.v.) injection of the inhibitor of nitric oxide synthase, N omega-nitro-L-arginine (NAME), 30 min before each training, and were then tested in the one-trial passive avoidance response and Morris water maze task, respectively. The results showed that: (1) among four concentrations of drug used, only doses higher than 3 mumol of i.c.v. NAME impaired learning and memory formation significantly (p < 0.05) in both test models; (2) in Morris water maze task, the animals treated with highest dose of NAME (5 mumol) failed to learn while those treated with lower doses succeeded; (3) in Morris water maze task, the i.c.v. NAME, even in higher doses, did not affect the capacity of finding a visible platform. It is suggested that NO is involved in learning and memory formation by potentiating or facilitating mainly the acquisition process.

[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.

[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.