Risk factors and mortality associated with multi-drug-resistant Gram-negative bacterial infection in adult patients following abdominal surgery.

BACKGROUND: Multi-drug-resistant (MDR) Gram-negative bacterial (GNB) infection remains a significant cause of morbidity and mortality among surgical patients. The objective of this study was to recognize the risk factors for MDR GNB infection in patients following abdominal surgery, and determine the predictors independently associated with death. METHODS: From 2010 to 2017, a retrospective cohort study was conducted among patients with abdominal surgery admitted to the surgical intensive care unit (ICU). Patients with GNB infection were included for analyses. RESULTS: In total, 364 patients experienced GNB infection following abdominal surgery. Of these, 117 (32.1%) were MDR GNB infection. Of 133 MDR GNB isolates, the most common isolate was Escherichia coli (45.1%). Patients with MDR GNB infection had significantly longer ventilator-days and hospital stay, as well as higher 30-day and in-hospital mortality compared with non-MDR GNB patients. Multi-variable analysis showed that longer length of pre-ICU stay, surgical re-exploration, receipt of group 2 carbapenems (e.g. imipenem, meropenem and doripenem) and fluoroquinolones, and higher total bilirubin were independent risk factors for the acquisition of MDR GNB infection. Predictors for 30-day mortality among patients with MDR GNB infection were chronic kidney disease, receipt of group 2 carbapenems and inappropriate empirical antimicrobial therapy. CONCLUSIONS: This study provides important information about the risk factors for MDR GNB infection and 30-day mortality among patients following abdominal surgery.

Electron microscopic radioautographic studies of the carotid body following injections of labeled biogenic amine precursors.

Adult Syrian hamsters were given a subcutaneous injection of reserpine 3 days before an intraperitoneal injection of (3)H-3,4 dihydroxyphenylalanine or (3)H-5, hydroxytryptophan and the carotid bodies were subsequently prepared for electron microscopic radioautography. Other Syrian hamsters were given a subcutaneous injection of reserpine and the carotid bodies were subjected to a sensitive cytochemical test for the detection of unsubstituted amines. These studies were made to determine whether the labeled amine precursors were incorporated into the cells and to see whether the parenchymal cells were affected by reserpine treatment. Material from hamsters treated first with reserpine and subsequently injected with (3)H-3,4 dihydroxyphenylalanine or (3)H-5, hydroxytryptophan exhibited reduced grains of silver over the cells which were associated mainly with the dense cores of the cytoplasmic granules. These studies offer evidence that the granules of the carotid body incorporate catecholamine and indolamine precursors. Material from hamsters incubated for the presence of unsubstituted amines gave a positive reaction (opaque cytoplasmic granules) for catecholamines but not for indolamines. The latter substances may not be present in quantities sufficient to register a positive reaction in the cytochemical test. The opaque granules, indicative of the presence of catecholamines, decreased in density after reserpine treatment. 5 days after one reserpine injection the granules had regained opacity and were comparable to those seen in the control cells.

The effects of reserpine and hypoxia on the amine-storing granules of the hamster carotid body.

The carotid bodies from control, reserpine-treated, and hypoxia-treated hamsters were fixed with phosphate-buffered glutaraldehyde and osmium tetroxide, s-Collidine-buffered osmium tetroxide, or phosphate-buffered glutaraldehyde followed by potassium dichromate incubation. Following glutaraldehyde-osmium tetroxide fixation no differences in density or population of the electron-opaque granules in the glomus cells of either control or experimental animals were observed. With s-Collidine-buffered osmium tetroxide and the glutaraldehyde-dichromate technique a marked decrease in density without an appreciable reduction in number of granules was noted after reserpine treatment, while in hypoxia-treated hamsters the density and population of the granules were not different from those of the controls. The results indicate that reserpine depletes the amines without granule disappearance and that hypoxia does not affect the amine content of the granules. It is suggested that following glutaraldehyde-osmium tetroxide double fixation, persistence of the density of the granules in reserpine-treated animals is due primarily to the nonamine content, and that the amines in the glomus cells are probably not directly involved in the respiratory reflex.

Effects of sinus nerve stimulation on carotid body glomus cells.

The sinus nerve or sympathetic trunk was stimulated unilaterally in one group of adult cats or Syrian hamsters while in another group the sinus nerve or sympathetic trunk was cut unilaterally and the animals were given reserpine. In a third group, atropine was administered prior to sinus nerve stimulation. All tissues were processed for the detection of primary monoamines. The carotid bodies on the operated sides were compared with those on the unoperated sides of the same animal in order to determine if amine depletion occurred following the experimental procedures. After sinus nerve stimulation alone, the density of the granules in the glomus cells was decreased, but changes were not noted in the granules following sympathetic nerve stimulation. Sinus nerve stimulation after atropine administration resulted in no change in granule density. Sinus nerve transection followed by reserpine treatment resulted in a greater decrease in granule density on the unoperated than on the operated side. Transection of the sympathetic components to the carotid body followed by reserpine injections resulted in a decrease in granule density in the glomus cells on both the operated and unoperated sides. These results suggest that the sinus nerve must be intact for reserpine to exert an effect and that the sinus nerve may contain efferent fibers which modulate amine secretion.

Amitriptyline modulated Ca2+ signaling and induced Ca2+-independent cell viability in human osteosarcoma cells.

Amitriptyline is a widely used tricyclic antidepressant, which acts primarily as a serotonin-norepinephrine reuptake inhibitor. This study examined the effect of amitriptyline on Ca2+ homeostasis and its related mechanism in MG63 human osteosarcoma cells. Amitriptyline evoked cytosolic-free Ca2+ concentrations ([Ca2+]i) rises concentration dependently. Amitriptyline-evoked Ca2+ entry was confirmed by Mn2+-induced quench of fura-2 fluorescence. This entry was inhibited by Ca2+ entry modulators nifedipine, econazole, SKF96365, the protein kinase C (PKC) activator phorbol 12-myristate 13 acetate but was not affected by the PKC inhibitor GF109203X. In Ca2+-free medium, treatment with the endoplasmic reticulum Ca2+ pump inhibitor thapsigargin (TG) inhibited amitriptyline-evoked [Ca2+]i rises by 95%. Conversely, treatment with amitriptyline abolished TG-evoked [Ca2+]i rises. Inhibition of phospholipase C (PLC) with U73122 inhibited amitriptyline-evoked [Ca2+]i rises by 70%. Amitriptyline killed cells at 200-500 µM in a concentration-dependent fashion. Chelating cytosolic Ca2+ with 1,2-bis(2-aminophenoxy)ethane- N, N, N', N'-tetraacetic acid/AM did not reverse amitriptyline-induced cytotoxicity. Collectively, our data suggest that in MG63 cells, amitriptyline induced [Ca2+]i rises by evoking PLC-dependent Ca2+ release from the endoplasmic reticulum and Ca2+ entry via PKC-regulated store-operated Ca2+ entry. Amitriptyline also induced Ca2+-disassociated cell death.

Role of endogenous prostaglandin E2 in erythropoietin production and dome formation by human renal carcinoma cells in culture.

Studies were carried out on the role of endogenous prostaglandin E2 (PGE2) in erythropoietin (Ep) production and dome formation in primary monolayer cultures of a human renal carcinoma from a patient with erythrocytosis that has been serially transplanted into BALB/c athymic nude mice. The metabolism of [14C]arachidonic acid (14C-AA) by cultured renal carcinoma cells, which were plated in 25-cm2 flasks at a density of 2 X 10(4) cells/cm2 and grown for 6, 12 (confluence, 13 X 10(4) cells/cm2), 16, 24, and 30 d in Eagle's minimum essential medium (MEM) supplemented with 10% fetal bovine serum, was examined by using radiometric thin-layer chromatography (TLC). TLC revealed PGE2 to be the major metabolite of 14C-AA produced by the cultured cells throughout the 30 d of cultivation. In addition, the cultured cells at each time period were incubated for 24 h in 5 ml of serum-free Eagle's MEM and the levels of PGE2 and Ep in the incubated media were measured via radioimmunoassay. PGE2 levels in the serum-free media incubated with the cultured cells grown for 6 d were significantly (P less than 0.001) elevated (174 +/- 2.5 pg/ml, n = 5), compared with the unincubated control media (1.5 +/- 0.19 pg/ml, n = 5) and gradually decreased at each time period to 97.6 +/- 4.4 pg/ml (n = 5) at 30 d. On the other hand, the levels of Ep in the incubated media of the cells grown for 6 d were 11.5 +/- 0.52 mU/ml (n = 5) compared with 7.6 +/- 0.62 mU/ml (n = 5) in the control media. However, after the cultured cells became confluent, the levels of Ep in the incubated media showed a marked increase to 222.9 +/- 5.26 mU/ml (n = 5) at 30 d of cultivation. Multicellular hemicysts (domes) developed after the cultured cells reached confluence and their numbers increased with increasing time in confluence in parallel with the increase in Ep. Meclofenamate (MF) (3 X 10(-6)-3 X 10(-5) M), a prostaglandin synthesis inhibitor, produced a significant dose-related decrease in PGE2, Ep, and dome formation without producing a significant effect on cell viability in the 30-d cells. This inhibitory effect of MF on Ep production and dome formation was completely abolished by the addition of 10(-8) M PGE2 to the incubation medium. In conclusion, endogenous PGE2 plays an important role in supporting and/or stimulating Ep production and dome formation in cultured renal carcinoma cells.

Evaluation of wound healing effect on skin-defect nude mice by using human dermis-derived mesenchymal stem cells.

We report that human dermis-derived mesenchymal stem cells (hDMSCs) possess differentiation potential of epidermis facilitating wound healing in skin-defect nude mice in combination with the treatment using gelatin/thermosensitive poly N-isopropylacrylamide (pNIPAAm)/polypropylene (PP). The results showed that the rate of cell growth and wound recovery in the hDMSC and gelatin/pNIPAAm/PP-treated group was significantly greater than those in the gelatin/pNIPAAm/PP-treated only group (P < .01). The reepithelialization marker of human pan-cytokeratin was also significantly increased on days 14 and day 21 in the wound site of hDMSCs and gelatin/pNIPAAm/PP-treated group. Furthermore, the stem cell marker of human CD13 gradually decreased during the period of wound healing. In sum, this novel method provided a transferring system for stem cell therapy, maintaining its temperature-sensitive property of easy peeling by lower temperature treatment.

Satellite videoconferencing for healthcare workers: audience characteristics and the importance of continuing education credits.

To assess the opinions of healthcare workers (HCWs) about a satellite videoconference as a means of earning continuing education credit, a telephone survey was conducted in September 1998, 1 month after a live interactive satellite videoconference on antimicrobial use and resistance. There were 180 registered sites in 45 states surveyed, representing 1,589 viewers: 764 nurses (48.1%), 201 physicians (12.6%), and 624 other HCWs (39.3%). Continuing education credit was requested by 51% of nurses, 31% of physicians, and 27% of all other HCWs. Although preferred learning formats varied, 70% of respondents said it was important to offer continuing education credit. Furthermore, 31% of the respondents stated that the videoconference influenced institutional strategies. We concluded that satellite videoconferences are a method to reach audiences around the world efficiently and effectively, provide the latest information, facilitate interaction, and meet some of the demand for continuing education credit for HCWs.

Induction of calcium release from isolated sarcoplasmic reticulum by triphenyltin.

A direct peripheral myopathy has been found in organotin intoxication and suggested to be a significant factor in the development of muscle weakness following exposure. In this study, by using the isolated sarcoplasmic reticulum membrane vesicles, we have shown that triphenyltin dose-dependently induced Ca2+ release from the actively and passively loaded sarcoplasmic reticulum vesicles. Triphenyltin induced Ca2+ release in ruthenium red-sensitive and insensitive ways with EC50 values of 75 and 270 microM, respectively. The Ca2+-ATPase activity and Ca2+ uptake of sarcoplasmic reticulum were also inhibited by triphenyltin. Triphenyltin exerted dual effects on the apparent [3H]ryanodine binding. Triphenyltin (0.5-10 microM) dose-dependently potentiated the [3H]ryanodine binding; however, the [3H]ryanodine binding decreased as the concentration of triphenyltin increased. The dissociation of bound [3H]ryanodine was facilitated by triphenyltin. The present study suggested that the internal Ca2+ store of skeletal muscle could be depleted by triphenyltin through the inhibition of the Ca2+ uptake and the induction of Ca2+ release by acting on the Ca2+-ATPase and Ca2+ release channel, also known as the ryanodine receptor, of sarcoplasmic reticulum, respectively. These results could partly explain the development of muscle weakness in organotin intoxication; however, their relevance to the development of peripheral myopathy requires further examination.

Synaptic morphology of substance P terminals on catecholamine neurons in the commissural subnucleus of the nucleus tractus solitarii in the rat.

The ultrastructure of substance P-containing nerve terminals synapsing on catecholamine neurons in the rat commissural subnucleus of the nucleus tractus solitarii (NTScom) was studied using a double immunocytochemical labeling technique. Although there were numerous tyrosine hydroxylase-immunoreactive (TH-I) somata present, substance P immunoreactive (SP-I) cell bodies were only occasionally found in the NTScom. At the light microscopic level, many SP-I terminals were seen closely associated with TH-I dendrites and somata. At the electron microscopic level, SP-I terminals synapsing on TH-I structures were also readily encountered. SP-I terminals contained small, clear, and predominantly spherical vesicles (32 +/- 4 nm diameter), as well as large dense-cored vesicles approximately 100 nm in diameter. Postsynaptic TH-I dendritic profiles of various calibers and somata were encountered. These postsynaptic TH-I structures often showed postsynaptic densities. The morphological features of the SP-TH synapses in the present study, that is, the size of synaptic vesicles and the presence of postsynaptic densities, are quite different from those of central carotid sinus afferent synapses reported in our previous study [Chen et al. (1992), J. Neurocytol., 21:137-147]. Therefore, most of the SP terminals of the SP-TH synapses in the NTScom appear not to originate from the carotid sinus afferents. SP-I second-order neurons of the carotid sinus afferent pathway [Chen et al. (1991), J. Auton. Nerv. Syst., 33:97-98] may be one of the possible sources of such terminals.

The pretectal complex of the cat: cells of origin of projections to the pulvinar nucleus.

The pretectal projection to the pulvinar nucleus in the cat was examined using the retrograde transport of wheat germ agglutinin-horseradish peroxidase. These data show that both visual and non-visual areas of the pretectal complex contribute to the projection. Specifically, large numbers of labeled neurons are located within the pretectal olivary nucleus with a substantial number of labeled neurons observed within the nucleus of the optic tract. Labeled neurons are also located within the medial, anterior and posterior nuclei, but not to the degree observed in the other pretectal nuclei. Morphometric analysis of labeled and Nissl-stained neurons indicate that the pretectopulvinar pathway is not correlated to any single cell size.

Systemic administration of a water-soluble hexasulfonated C(60) (FC(4)S) reduces cerebral ischemia-induced infarct volume in gerbils.

Buckminsterfullerence and its derivatives have recently been shown to exhibit considerable in vivo biological activities. A water-soluble hexasulfonated C(60) (FC(4)S) has been shown to protect against oxidative stress. Neuroprotective effects of FC(4)S were investigated in the present study. Focal cerebral ischemia was produced by a permanent occlusion of the right middle cerebral artery in gerbils. Infarct volumes were determined by 2,3,5-triphenyltetrazolium chloride transcardiac perfusion 24 h after cerebral ischemia. Chronic pretreatment of FC(4)S (0.5 and 5.0 mg/kg/day, intraperitoneally for 2 weeks) significantly reduced the infarct volume (by 42% and 68%, respectively) when compared to that of the control group. Results revealed that chronic pretreatment of FC(4)S may protect the brain against focal cerebral ischemia.

Mediation of gamma-hexachlorocyclohexane-induced DNA fragmentation in HL-60 cells through intracellular Ca2+ release pathway.

The cytotoxicity of gamma-hexachlorcyclohexane (gamma-HCC) was evaluated in HL-60 cells. Gamma-HCC dose-dependently induced cytotoxicity of HL-60 with an IC50 value of 60+/-5 microM. The gamma-HCC treated cells showed some characteristic changes of apoptosis, including blebbing of the membrane, condensation of the nuclear chromatin, vacuolation of cytoplasm and internucleosomal DNA fragmentation. Gamma-HCC induced DNA fragmentation of HL-60 cells in a dose-, time- and Ca2+-dependent manner. The DNA fragmentation induced was inhibited by intracellular Ca2+ chelator, calmodulin antagonist and Ca2+ sensitive endonuclease inhibitor. Gamma-HCC caused a steady increase in the cytosolic free Ca+ concentration due to release from intracellular stores. Neither the DNA fragmentation nor the increase of intracellular Ca2+ induced by gamma-HCC was inhibited by the removal of extracellular Ca2+. These data suggested that the cytotoxicity of gamma-HCC in HL-60 cells is mediated by the increase of intracellular Ca2+ concentration and the activation of Ca2+-dependent endonuclease, which triggers apoptosis in a Ca2+ and calmodulin-dependent manner.

The cellular localization of vasoactive intestinal peptide (VIP) in the mouse median eminence by immuno-electron microscopy.

The aim of this study was to examine, by use of pre-embedding immunocytochemistry, the ultrastructural localization of vasoactive intestinal peptide (VIP) immunoreactivity in the mouse median eminence. VIP immunoreactivity was observed in axonal profiles. The VIP-immunoreactive axonal profiles were in close proximity to non-immunoreactive axonal profiles that contained dense granular vesicles and clear vesicles and also to processes of tanycytes. VIP-immunoreactive terminals were observed in the proximity of the perivascular space and in the neuropil. Our results suggest that VIP-immunoreactive axon terminals may possibly interact with other non-immunoreactive axon terminals containing peptide and/or other transmitters at the level of the median eminence or may be released to the portal vasculature thereby to effect anterior pituitary cells.

Incidence of hepatitis C infection in a hepatitis C endemic township in southern Taiwan.

To realize the incidence of hepatitis C virus (HCV) infection in an HCV endemic township, Tzukuan, in Taiwan, we conducted a follow-up community-based survey. A total of 173 adults, 82 males and 91 females, with mean age of 55.5 +/- 9.9 years received initial and follow-up anti-HCV tests with one-year interval. One (1.2%, 95% CI: 0%-5.5%) of 84 anti-HCV-positive subjects was negative-seroconversion, and 4 (4.5%, 95% CI: 0.2%-8.8%) of 89 anti-HCV-negative subjects were positive-seroconversion. The results indicated that hepatitis C might be still spreading in the HCV-endemic area now.