Antifungal susceptibility profile of Candida clinical isolates from 22 hospitals of São Paulo State, Brazil

This study aimed to evaluate the frequency of cryptic Candida species from candidemia cases in 22 public hospitals in São Paulo State, Brazil, and their antifungal susceptibility profiles. During 2017 and 2018, 144 isolates were molecularly identified as 14 species; C. parapsilosis (32.6%), C. albicans (27.7%), C. tropicalis (14.6%), C. glabrata (9.7%), C. krusei (2.8%), C. orthopsilosis (2.8%), C. haemulonii var. vulnera (2.1%), C. haemulonii (1.4%), C. metapsilosis (1.4%), C. dubliniensis (1.4%), C. guilliermondii (1.4%), C. duobushaemulonii (0.7%), C. kefyr (0.7%), and C. pelliculosa (0.7%). Poor susceptibility to fluconazole was identified in 6.4% of C. parapsilosis isolates (0.12 to >64 µg/mL), 50% of C. guilliermondii (64 µg/mL), 66.6% of C. haemulonii var. vulnera (16-32 µg/mL), and C. duobushaemulonii strain (MIC 64 µg/mL). Our results corroborated the emergence of C. glabrata in Brazilian cases of candidemia as previously reported. Importantly, we observed a large proportion of non-wild type C. glabrata isolates to voriconazole (28.6%; <0.015 to 4 µg/mL) all of which were also resistant to fluconazole (28.6%). Of note, C. haemulonii, a multidrug resistant species, has emerged in the Southeast region of Brazil. Our findings suggested a possible epidemiologic change in the region with an increase in fluconazole-resistant species causing candidemia. We stress the relevance of routine accurate identification to properly manage therapy and monitor epidemiologic trends.

2420Effects of a selective small-molecule formyl peptide receptor 2 agonist on post myocardial inflammation and left ventricular structure-function relationships

Background/Introduction

Dysregulated inflammation following myocardial infarction (MI) can lead to maladaptive infarct healing, myocardial damage and heart failure. Formyl peptide receptor 2 (FPR2) plays an important role in the ligand-dependent regulation of inflammation resolution. Stimulation of resolution via FPR2 activation is hypothesized to preserve left ventricular (LV) structure-function relationships thereby preventing pathological cardiac remodeling, and heart failure.

Purpose

We evaluated a selective 4-phenylpyrrolidinone FPR2 agonist in rodent MI models by assessing the impact on LV and infarct scar remodeling and cardiac function.

Methods

The FPR2 agonist was evaluated in phagocytosis, chemotaxis and cytokine response assays. In vivo, following permanent occlusion of the left anterior descending (LAD) artery, C57BL/6 mice or Sprague-Dawley rats were treated with the FPR2 agonist or vehicle; PO gavage, QD. Treatment began 24 hours after occlusion (0.3 and 3 mg/kg) and continued for three days to assess early inflammation or four weeks to evaluate LV and infarct structure and function. Rats subjected to permanent MI were treated 48 hours after occlusion (0.01, 0.1. 1, 10 mg/kg) for six weeks to assess structure-function relationships. A parallel study in rats evaluated compound treatment (0.01, 0.1. 1, 10 mg/kg) following 60 minutes occlusion and reperfusion of the LAD artery.

Results

The FPR2 agonist enhanced cellular phagocytosis and chemotaxis, and stimulated IL-10 and MCP-1 gene expression in isolated human whole blood. In mice, FPR2 agonist treatment improved survival post MI, reduced LV chamber area and infarct size (26% and 55% vs. vehicle, respectively, P<0.05) and preserved infarct wall thickness (59% vs. vehicle, P<0.05). Treatment increased macrophage arginase 1 levels three days post-MI in the infarct border zone and CD206 levels in the whole heart, indicating a shift towards a pro-resolution phenotype. In rats, FPR2 agonist treatment preserved infarct wall thickness (maximal at 10 mg/kg, 96% vs. vehicle, P<0.05) and increased LV ejection fraction at all doses (+9% vs. vehicle, P<0.05). Following occlusion and reperfusion of the LAD artery, treatment preserved viable myocardium across the infarct wall at multiple doses (25–41%, P<0.05) resulting in increased ejection fraction (14% and 19% vs vehicle at 0.01 and 1 mg/kg, respectively, P<0.05).

Conclusion(s)

Improvements in cardiac structure-function versus vehicle treated animals support the concept that agonism of FPR2 improves post-MI wound healing, limiting adverse post-MI LV remodeling, thereby preserving cardiac function. These preclinical results suggest targeting FPR2 may present an innovative approach towards development of effective drug therapies to prevent heart failure post-MI.

Acknowledgement/Funding

Bristol-Myers Squibb Company

High-dose (5000-μg) Intravitreal Ganciclovir Combined with Highly Active Antiretroviral Therapy for Cytomegalovirus Retinitis in HIV-Infected Patients in Venezuela

Purpose

To describe the use of high doses of intravitreal ganciclovir combined with highly active antiretroviral therapy (HAART) for the treatment of cytomegalovirus (CMV) retinitis in human immunodeficiency virus (HIV)-infected patients.

Methods

Thirteen HIV-infected patients (18 eyes) with active CMV retinitis (83.3% in zone 1 and 38.4% resistant) participated in this prospective interventional case series. Patients were treated with high dose intravitreal ganciclovir (5.0 mg/0.1 mL once a week) in combination with HAART therapy. Intravitreal injections were discontinued once CMV retinitis healed if there was a significant increase in CD4+ count (any increase of ≥50 cells/μL to levels over 100 cells/μL sustained for at least 3 months). Mean follow-up was 15.6 months. Main outcome measures included assessment of visual acuity and retinal inflammation (CMV retinitis activity). A matched historical control group of 20 eyes (15 patients) with CMV retinitis treated with systemic ganciclovir (intravenous [induction] and oral [maintenance]) was included.

Results

Complete regression of the retinitis was obtained with high doses of intravitreal ganciclovir in 88.8% of eyes (two patients died during follow-up) at a mean of 4.5 weeks (2 to 8 weeks). Visual acuity improved two or more lines in 61.1% of eyes. No ganciclovir retinal toxicity was identified. Three eyes presented CMV retinitis reactivation at a mean of 25.6 days after their last injection. Complications (33.3%) included retinal detachment (RD; 3 eyes), immune recovery uveitis (IRU; 2 eyes), and endophthalmitis (1 eye). In our control group complete regression of the retinitis was obtained in 100% of eyes at a mean of 4 weeks (3 to 7 weeks). However, 12 eyes (60%) presented with CMV retinitis relapse at a mean of 29 days (21 to 32 days) after initiating oral ganciclovir (maintenance). Complications included RD (7 eyes, 35%) and IRU (3 eyes, 15%). Severe neutropenia occurred in 2 patients (13%).

Conclusions

High doses of intravitreal ganciclovir (5.0 mg) once a week in combination with HAART therapy is effective to control CMV retinitis, and may be discontinued after CMV retinitis has healed if immune reconstitution with a significant increase in CD4+ count has occurred.

The effect of chicken blood and its components on wastewater characteristics and sewage surcharges

Local wastewater treatment authorities levy surcharges from their non-residential customers that are based, in part, on the concentration of various pollutants in the customer's wastewater. Blood has long been recognized as the most potent contributor to pollutant loads in chicken processing plant wastewater. Quantification of the impact of blood on wastewater characteristics and sewage surcharges is hindered by lack of information on specific characteristics of chicken blood, and by the highly variable methods used by local authorities for calculating surcharges. In this study, the most commonly used wastewater characteristics are determined for whole chicken blood as well as its individual components. The characteristics measured include biochemical oxygen demand, chemical oxygen demand, total suspended solids, fats oil and grease, total Kjeldahl nitrogen, ammonia, and total phosphorus. Sewage surcharge calculation methods were collected from 71 local wastewater authorities. The results show all components of the blood to be extremely high-strength pollutants. The impact of blood on sewage surcharges is shown to be highly variable depending on the rates applied by the local authority.

Flocculation of high purity wheat straw soda lignin

In industrial process, acidification causes non-sulfonated lignin insolubility. The flocculants poly(diallyldimethylammonium chloride) (pDADMAC) and bovine blood (BB) also caused lignin insolubility while cationic polyacrylamide, chitosan, and soy protein PF 974 were ineffective. Turbidity determined optimal flocculant, but turbidity magnitude with BB was greater than expected. pDADMAC caused negative lignin Zeta potential to became positive, but BB-lignin Zeta potential was always negative. Insoluble lignin did not gravity sediment, and flocculant-lignin mixtures were centrifuged. Pellet and supernatant dry mass and corrected spectroscopic results were in good agreement for optimal pDADMAC and BB. Spectroscopy showed 87-92% loss of supernatant lignin. Nitrogen analysis showed BB concentrated in the pellet until the pellet became saturated with BB. Subtracting ash and BB mass from pellet and supernatant mass confirmed optimal BB. Low levels of alum caused increased lignin flocculation at lower levels of pDADMAC and BB, but alum did not affect optimal flocculant.

Improved prediction of meat and bone meal metabolizable energy content for ducks through in vitro methods

Apparent metabolizable energy (AME) of meat and bone meal (MBM) for poultry is highly variable, but impractical to measure routinely. Previous efforts at developing an in vitro method for predicting AME have had limited success. The present study uses data from a previous publication on the AME of 12 MBM samples, determined using 288 White Pekin ducks, as well as composition data on these samples. Here, we investigate the hypothesis that 2 noncompositional attributes of MBM, particle size and protease resistance, will have utility in improving predictions of AME based on in vitro measurements. Using the same MBM samples as the previous study, 2 measurements of particle size were recorded and protease resistance was determined using a modified pepsin digestibility assay. Analysis of the results using a stepwise construction of multiple linear regression models revealed that the measurements of particle size were useful in building models for AME, but the measure of protease resistance was not. Relatively simple (4-term) and complex (7-term) models for both AME and nitrogen-corrected AME were constructed, with R-squared values ranging from 0.959 to 0.996. The rather minor analytical effort required to conduct the measurements involved is discussed. Although the generality of the results are limited by the number of samples involved and the species used, they suggest that AME for poultry can be accurately predicted through simple and inexpensive in vitro methods.

Proteins and peptides as renewable flocculants

Partially hydrolyzed extracts from blood meal, feather meal, and meat and bone meal, as well as a variety of common surplus agricultural proteins were tested for their ability to promote the flocculation of clay. Partial alkaline or enzymatic hydrolyses of blood meal, feather meal, and meat and bone meal were performed to liberate proteins and peptides from their water-insoluble forms. Some of these extracts promoted flocculation. However, if hydrolysis was extensive, low molecular weight peptides were mainly produced, and these extracts did not promote flocculation. Beef skin gelatins and hydrolyzed fish collagen were found to promote flocculation when pH 5.5 buffer was added. Commercial preparations of peptone enzymatic digest and a mixture of keratin and hydrolyzed keratin did not promote flocculation.

Meat & bone meal extract and gelatin as renewable flocculants

Readily available proteins were tested as renewable flocculants, and their actions were compared to that of anionic PAM, a common, commercial flocculant that requires the coaddition of a calcium ion source. Two soy proteins, a whey fraction, a porcine gelatin, and a meat & bone meal (MBM) extract were used in the flocculation test. It was found that MBM extract and porcine gelatin promoted clay flocculation, and flocculation was complete by 24h with or without the addition of calcium chloride. The other tested proteins did not promote clay flocculation, but all of the proteins were found to be adsorbed to clay. The protein adsorptions were well described by the Langmuir model, and gelatin and MBM extract had higher maximum adsorption capacities than the other proteins. Zwitterionic buffer solutions at pH 5.5, 7.0, and 10.0 were tested in the flocculation experiments. Addition of the pH 5.5 buffer caused the two soy proteins to become clay flocculants and lowered the concentration of gelatin and MBM extract necessary to promote complete flocculation by 24h. Calcium chloride was not required for flocculation. Under optimal testing conditions, the dried weight of gelatin or MBM extract was 2.6 and 17 times higher, respectively, than the weight of anionic PAM required for complete flocculation at 24h.

Factors contributing to the poor bulk behavior of meat and bone meal and methods for improving these behaviors

Meat and bone meal (MBM), a product of the rendering industry, is a potential feedstock for numerous bio-based applications. Design of processing equipment for MBM is difficult due to MBM's bulk behaviors; it flows less easily than many other granular materials, and it tends to foul the surfaces of processing equipment. This study examines the major factors contributing to MBM's poor bulk behavior, including moisture content, fat content, particle size distribution and temperature, and the relative importance of these factors. Potential methods for improving MBM's bulk properties, including use of an anti-caking agent, dehydration, fat extraction, milling and refrigeration are also studied. The effects of these factors were determined by a standard laboratory measurement, the Hausner ratio, as well as by the rate of surface-fouling and dust generation using a pilot-scale aspirator. In contrast to past studies with other granular materials, moisture content was shown to have an insignificant effect on MBM's bulk behavior. The results, however, show that MBM fat content is a major determinant of the bulk behavior of the MBM. Reduction of fat content resulted in major changes in MBM's bulk behavior, by all measures used. Less dramatic changes were achieved through refrigeration to solidify the fat and/or treatment with an anti-caking agent.

A novel mutation in the E-cadherin gene in the first family with hereditary diffuse gastric cancer reported in Spain

AIMS

Mutations of the E-cadherin gene (CDH1) result in dominantly inherited hereditary diffuse gastric cancer (HDGC). We report a study in the first family diagnosed with HDGC in Spain, examining the presence of mutations in the CDH1 gene.

METHODS

The presence of mutations was studied by direct sequencing of all CDH1 exons. Immunohistochemical analysis with specific antibodies was used to detect the expression of E-cadherin in normal and tumour tissue.

RESULTS

A novel 1610delC mutation in exon 11 has been found in a Spanish family diagnosed with HDGC. This mutation generates a premature stop codon at position 1667 giving rise to a truncated protein that lacks the transmembrane and beta-catenin-binding domains. The presence of a 1610delC germline mutation was confirmed in three family members diagnosed with diffuse gastric cancer, and also in six asymptomatic members. Of note, the diffuse gastric cancer coexisted with a gastric lymphoma in the proband. Furthermore, immunohistochemical analyses of tumour tissue showed the complete absence of E-cadherin in the proband, revealing a second genetic hit at the CDH1 locus.

CONCLUSIONS

We have identified a HDGC family in Spain that carries a novel germline truncating mutation in the CDH1 gene.

Simultaneous measurement of 19 components in serum-containing animal cell culture media by fourier transform near-infrared spectroscopy

Animal cell cultures generate maximal amounts of desired products when maintained in a controlled environment with low and constant concentrations of nutrients and wastes. Traditionally this has involved slow addition of glucose and glutamine; however, recent studies have indicated that a number of low concentration amino acids are required to prevent initiation of apoptosis. Therefore, optimal control of animal cell cultures will likely require measurement of a large number of chemical components. We present here the evaluation of a near-infrared spectroscopic (NIRS) monitoring scheme to quantify 19 cellular nutrients and wastes in culture medium with and without serum. The components include glucose, lactate, ammonia, pyruvate, glutamine, and 14 other amino acids. Spectroscopic calibrations were generated for a synthetic version of a standard culture medium (DMEM) in which the concentrations of 17 DMEM components and ammonia and lactate were varied in a random fashion. This randomization provides a stringent evaluation of the measurement scheme. Reasonably accurate measurements of these 19 components could be accomplished in the absence or presence of 10% horse serum by volume with percent errors ranging from 3% to 37%. Analytes with concentrations as low as 0.3 mM could be reliably quantified. The presence of serum, when properly included in the calibration, has little effect on measurement error. These results provide an important step toward application of NIRS for monitoring the large number of varying components of animal cell cultivations.

The neuregulin receptor ErbB-4 interacts with PDZ-containing proteins at neuronal synapses

Neuregulins regulate the expression of ligand- and voltage-gated channels in neurons and skeletal muscle by the activation of their cognate tyrosine kinase receptors, ErbB 1-4. The subcellular distribution and mechanisms that regulate the localization of ErbB receptors are unknown. We have found that ErbB receptors are present in brain subcellular fractions enriched for postsynaptic densities (PSD). The ErbB-4 receptor is unique among the ErbB proteins because its C-terminal tail (T-V-V) conforms to a sequence that binds to a protein motif known as the PDZ domain. Using the yeast two-hybrid system, we found that the C-terminal region of ErbB-4 interacts with the three related membrane-associated guanylate kinases (MAGUKs) PSD-95/SAP90, PSD-93/chapsyn-110, and SAP 102, which harbor three PDZ domains, as well as with beta(2)-syntrophin, which has a single PDZ domain. As with N-methyl-D-aspartate (NMDA) receptors, ErbB4 interacts with the first two PDZ domains of PSD-95. Using coimmunoprecipitation assays, we confirmed the direct interactions between ErbB-4 and PSD-95 in transfected heterologous cells, as well as in vivo, where both proteins are coimmunoprecipitated from brain lysates. Moreover, evidence for colocalization of these proteins was also observed by immunofluorescence in cultured hippocampal neurons. ErbB-4 colocalizes with PSD-95 and NMDA receptors at a subset of excitatory synapses apposed to synaptophysin-positive presynaptic terminals. The capacity of ErbB receptors to interact with PDZ-domain proteins at cell junctions is conserved from invertebrates to mammals. As discussed, the interactions found between receptor tyrosine kinases and MAGUKs at neuronal synapses may have important implications for activity-dependent plasticity.

The effect of lipids on bongkrekic (Bongkrek) acid toxin production by Burkholderia cocovenenans in coconut media

Tempe bongkrek is an Indonesian food made by fermentation of coconut presscake or coconut milk residue Rhizopus oligosporus. Consumption of tempe bongkrek is associated with a food-borne human intoxication and significant numbers of deaths annually. The bacterium Burkholderia cocovenenans, which is the causative organism, produces two toxins, toxoflavin and bongkrekic acid (also commonly referred to as bongkrek acid). The reasons why these poisonings occur only in a very limited number of foods and only in isolated regions of the world are unclear. Our preliminary experiments in defined media and coconut investigated several compositional and environmental factors and suggested that lipid type and/or concentration were important. The effect of lipid concentration and fatty acid type on the production of bongkrekic acid by B. cocovenenans was examined by adding different amounts of coconut fat or individual free fatty acids to defatted and sterilized Rich Coconut Media (dRCM). The dRCM with added lipid was inoculated with B. cocovenenans, incubated at 30 degrees C for 5 days and the amount of bongkrekic acid formed quantified by HPLC. Coconut fat concentrations of 10% (dry basis) or less did not result in detectable amounts of bongkrekic acid even though the B. cocovenenans grew to high levels. Forty and 50% coconut fat resulted in as much as 1.4 mg/g bonkrekic acid (dry weight) at the same level of growth. Of eight saturated fatty acids tested, only lauric (12:0), myristic (14:0), and palmitic (16:0) acids stimulated the production of detectable amounts of toxin. When four 18-carbon free fatty acids with different degrees of saturation were compared, significant amounts of bongkrekic acid (2.62 mg/g dry weight) were produced only with oleic acid (18:1). These data indicate that the concentration and type of lipid in the substrate is critical for bongkrekic acid formation. This may explain why bongkrekic acid intoxication is limited to certain foods. Outbreaks associated with foods containing less than 20% fat may be a result of toxoflavin formation and not bongkrekic acid formation.

Heat and motion stability of polyvalent Crotalidae antivenin, ovine Fab

This study was conducted to test the hypothesis that a Fab-based crotalid antivenin (FabAV) in commercially packaged vials will remain effective under more extreme heat and motion conditions than would be expected in field settings. Vials containing FabAV were subjected to heat or motion. The effect of heat or motion on the ED50 of FabAV was determined using a mouse model of crotalid snake envenomation. The ED50 for the heat stability groups (expressed as a ratio of mg antivenin to mg venom) were as follows: 4 degrees C x 60 days (control) = 26.5, 70 degrees C x 60 days = 66.3, 70 degrees C x 30 days = 52.4, 50 degrees C x 60 days = 25.8, 50 degrees C x 30 days = 34.0. The ED50 for the two motion stability groups were similar: 4 degrees C x 60 days = 40.3 and 70 degrees C x 60 days = 48.3. These results indicate that FabAV is heat stable at 50 degrees C for 60 days, but had less potency when heated to 70 degrees C for 30 days. FabAV appears less potent after agitation, but remains effective in the mouse model. We conclude that FabAV can be safely stored for at least 60 days without refrigeration under most field conditions where snake envenomation may occur.

Properties of biomolecules measured from atomic force microscope images: a review

AFM images can be used to obtain quantitative or qualitative information about the properties of biomaterials. Examples presented here are: (1) Persistence length measurements of moving and stationary DNA molecules. (2) Force mapping to measure properties such as the elasticity of cells and vesicles. (3) Phase mode imaging to detect variations in materials and properties of the sample surface. (4) Imaging of surfaces at different constant forces.

Affinity-purified, mixed monospecific crotalid antivenom ovine Fab for the treatment of crotalid venom poisoning

SUBJECT OBJECTIVE

To test the efficacy and safety of a new antivenom, affinity-purified, mixed monospecific crotalid antivenom ovine Fab, in human subjects with minimal or moderate crotalid envenomation.

METHODS

We conducted a prospective multicenter clinical trial of 11 patients 10 years or older with progressive manifestations after mild to moderate crotalid snakebite. After giving their consent, subjects received four to eight vials of study drug and were then repeatedly examined over 48 hours and at 7 and 14 days after discharge. Each patient's clinical condition was evaluated serially with the use of a validated severity score, as well as on the basis of the investigator's assessment.

RESULTS

In all 11 subjects to the antivenom was judged by the investigator to have had a beneficial response. The severity score for each patient remained the same or decreased over the first 4 hours. However, two subjects demonstrated worsened condition 12 to 15 hours after antivenom administration. In no subject did an allergic reaction develop.

CONCLUSION

In this patient group, affinity-purified, mixed monospecific crotalid antivenom ovine Fab was associated with a halt of progressive crotalid venom poisoning. Initial safety data are promising but must be addressed further in subsequent studies.

Changes in the elastic properties of cholinergic synaptic vesicles as measured by atomic force microscopy

Cholinergic synaptic vesicles from Torpedo californica have been probed with the atomic force microscope in aqueous buffers to map and measure their elastic properties. Elastic properties were mapped with a new atomic force microscope technique known as force mapping. Force mapping of vesicles showed that the centers of the vesicles are harder or stiffer than the peripheral areas in the three buffers that were investigated. These were an isoosmotic buffer, a hypoosmotic buffer, and an isoosmotic buffer with 5 mM CaCl2 added. The hardness of the vesicular centers was quantified by calculation of the elastic modulus. Elastic moduli were in the range of 2-13 x 10(5) Pa. Vesicular centers were hardest in calcium-containing buffer and softest in isoosmotic buffer. Hypotheses are presented for the composition and function of the hard centers.

A neural network model of memory under stress

A model that attempts to simulate animal memory under stress is presented. For this purpose a model of selectable multiple associative memories is given. We consider two underlying types of memories: stressed and unstressed, implemented on the same neural network. In our model, learning into one or the other type of memory is done according to the stress of the individual at the time of learning. Memory retrieval is obtained according to a continuous function of the stress of the individual at the time of retrieval, who for low stress retrieves unstressed associations and for high stress retrieves stressed associations. Several biological results supporting this model are presented. A mathematical proof on the behaviour of the basins of attraction of the network as a function of stress is presented. Also a generalization to selectable multiple coexisting memories is given, and engineering and other applications of the model are suggested.

Underwater vehicles equipped with laser beacons and tracked from aircraft

The successful results of a feasibility experiment for tracking underwater vehicles equipped with laser beacons by aircraft equipped with detectors are presented. The system design focuses on tracking limited payload vehicles such as torpedoes in shallow-water (0-200 m) environments during Navy test and evaluation exercises. A compact, battery operated, Q-switched, frequency-doubled, dual-pulse Nd:YAG laser operating at 532 nm was used. The upward-pointing laser with a diffuse 14° output beam was mounted to a stationary buoy at a depth of five attenuation lengths. Aboard an SH3 helicopter at 5000 ft (1524 m), a 14° field-of-view avalanche photodiode detector system detected the first pulse that triggered an image-intensified CCD camera to image the second pulse at the ocean surface. When the results were scaled, we concluded that a coverage diameter of 14,375 m could be achieved at an aircraft elevation of 1 mile (1.6 km) with a signal-to-noise ratio of 10:1 for depths of ten attenuation lengths.

Esophagogastric devascularization and transection for bleeding esophageal varices: first case presentation

We present the first case of esophagogastric devascularization and esophagogastric transection using a stapler through laparoscopic surgery. The procedure was performed in a 71-year-old diabetic woman with alcoholic liver cirrhosis (Child-Pugh B class), portal hypertension, bleeding grade III esophageal varices, and a previous bleeding episode. The surgical technique was carried out without problems, and the patient had an excellent postoperative condition. Esophagogastric devascularization with esophageal transection using a stapler through laparoscopic surgery is a feasible technique that accomplishes the same and all objectives of the open procedure. Operative time in both methods is the same, whereas surgical trauma, inmunologic depletion, amount of transfused blood, pain, use of analgesics, and hospital stay are reduced in the laparoscopic technique.

Sequence-specific recognition of cytosine C5 and adenine N6 DNA methyltransferases requires different deformations of DNA

DNA methyltransferases modify specific cytosines and adenines within 2-6 bp recognition sequences. We used scanning force microscopy and gel shift analysis to show that M.HhaI, a cytosine C-5 DNA methyltransferase, causes only a 2 degree bend upon binding its recognition site. Our results are consistent with prior crystallographic analysis showing that the enzyme stabilizes an extrahelical base while leaving the DNA duplex otherwise unperturbed. In contrast, similar analysis of M.EcoRI, an adenine N6 DNA methyltransferase, shows an average bend angle of approximately 52 degrees. This distortion of DNA conformation by M.EcoRI is shown to be important for sequence-specific binding.

Ovine desipramine antibody fragments reverse desipramine cardiovascular toxicity in the rat

STUDY OBJECTIVE

To develop a model of severe desipramine cardiovascular toxicity and to determine whether partial neutralization of the antigen by desipramine-specific Fab antibody fragments ameliorates its cardiovascular effects.

METHODS

We administered desipramine to rats until the QRS interval tripled in duration and mean arterial pressure (MAP) was less than 100 mm Hg. Animals were then assigned to one of six groups: (1) no treatment, (2) normal saline solution control treatment (.9% NaCl infusion equal to the volume of Fab infusion), (3) nonimmune Fab control treatment (infusion of Fab equal to that in the 9.6% neutralization treatment), (4) 9.6% desipramine Fab (infusion of ovine desipramine Fab equal to 9.6% of an equimolar neutralization), (5) 19.2% desipramine Fab, and (6) 30.0% desipramine Fab.

RESULTS

QRS-interval duration, heart rate, and MAP were recorded for 60 minutes. Animals in groups 1 through 3 demonstrated slow and incomplete improvement. Animals in groups 4 through 6 showed improvement in QRS-interval duration and heart rate within 4 minutes (P<.05) compared with untreated animals. A dose-response relationship was evident; animals given the highest dose of desipramine-specific Fab showed the greatest improvement.

CONCLUSION

Partial neutralization of desipramine by specific Fab fragments produces rapid improvement of QRS-interval duration and heart rate in a rat model of severe desipramine toxicity.

Effects of early protein malnutrition and repeated testing upon locomotor and exploratory behaviors in the elevated plus-maze

An elevated plus-maze was used to investigate the effects of repeated testing on the locomotor and exploratory behaviors of malnourished rats. Pup malnutrition was induced during the lactation period (0 to 21 days of age) by feeding the dams a protein-deficient diet (6% protein) and the animals were allowed to recover from weaning to 70 days of age by eating a commercial lab chow diet. Control animals were suckled by dams receiving a normal protein diet (16% protein) during the lactation period and were fed a commercial lab chow diet after weaning. At 70 days, malnourished and control animals were placed on the central platform of the elevated plus-maze facing an enclosed arm and allowed to explore for 5 min. This procedure was repeated at 24-h intervals for 6 days. The repeated testing in the elevated plus-maze did not change the total number of arm entries and attempts to enter open arms, but decreased the percentage of open arm entries, time spent in open arms, and total time spent on the central platform. These data suggest an increase in anxiety with repeated testing in the elevated plus-maze. In addition, the malnourished animals showed a larger number of both rearings and attempts to enter the open arms, suggesting a high level of exploration and/or high impulsiveness of these animals as compared to control. The elevated plus-maze proved to be a useful animal model to evaluate exploratory behaviors in early protein malnourished animals.

The splanchnic organs, liver and kidney have unique roles in the metabolism of sulfur amino acids and their metabolites in rats

The arterial-venous differences for methionine and cysteine and their metabolites, glutathione, taurine and sulfate, were measured across the splanchnic organs, the liver, the kidney and the hindlimb of fed rats. Methionine and cysteine were released into the blood by the splanchnic organs and removed by the liver. These results indicate that more than half of the sulfur amino acids taken up by the liver were used for synthesis of glutathione for export into the plasma. The kidney removed about half of the glutathione exported by the liver, presumably due to action of gamma-glutamyl transpeptidase and dipeptidase, and released to the circulation a comparable amount of cysteine. Taurine, presumably from deconjugation of bile acids, was released into the plasma by the splanchnic organs; taurine was also released by the liver. The hepatosplanchnic release of taurine into the plasma indicates that the liver is the major site of taurine biosynthesis; taurine was removed by the kidney for excretion in the urine. A small amount of methionine was removed by the kidney, and the hindlimb released a small amount of glutathione and methionine into the plasma. The splanchnic organs seemed to remove substantial sulfate from the plasma in addition to that provided by the diet, and a net release of sulfate from the liver was observed. The relative roles of the various tissues in sulfate production and removal was not clear from these studies, due to the large variability in the arterial-venous differences observed.

Cysteine concentration regulates cysteine metabolism to glutathione, sulfate and taurine in rat hepatocytes

The effect of cysteine concentration and cysteine source [cysteine, methionine or 2-oxo-thiazolidine-4-carboxylate (OTC)] on the metabolism of [35S]cysteine was studied in isolated rat hepatocytes. Production of each of the major metabolites of cysteine (glutathione, sulfate, taurine) increased as cysteine or methionine, but not OTC, concentration in the medium was increased. At equimolar exogenous substrate concentrations, cysteine availability to hepatocytes was greater from exogenous cysteine than from methionine, and that from methionine was greater than from OTC. The partitioning of cysteine, or the percentage of total metabolism resulting in production of each of the major metabolites, was markedly affected by cysteine concentration or availability. Low cysteine availability favored its utilization for glutathione; high cysteine availability favored its catabolism to sulfate and taurine. Under conditions of low cysteine availability (incubations with 0.2 mmol/L OTC), glutathione, sulfate and taurine production accounted for 90, 10 and 1%, respectively, of total metabolism. Under conditions of high cysteine availability (incubations with 1 mmol/L cysteine + bathocuproine disulfonate), glutathione, sulfate and taurine production accounted for 19, 47 and 34%, respectively, of total metabolism. Cysteine supplied as such and cysteine formed intracellularly from methionine were similarly partitioned. These studies demonstrate that methionine is not a superior substrate to cysteine for hepatic glutathione synthesis and that cysteine concentration (presumably intracellular cysteine concentration) has a major effect on the partitioning of cysteine sulfur to taurine in rat hepatocytes.

Measurement of cyst(e)amine in physiological samples by high performance liquid chromatography

Two methods for measurement of cyst(e)amine in physiological samples are described. One method involves reduction of disulfides present in the sample with tributylphosphine, reversed phase chromatography of thiols, and electrochemical detection of cysteamine and other thiols. The other method involves reduction of disulfides with dithiothreitol, derivatization of thiols with 7-diethylamino-3-(4'-maleimidylphenyl)-4-methylcoumarin, separation of these derivatives by reversed phase chromatography, and fluorometric detection of the thiol adducts. The endogenous concentration of cysteamine in rat liver was estimated to be less than 2.5 nmol/g. Cysteamine is produced in tissues postmortem; rapid sampling/freezing of tissues and rapid inactivation of enzymes during tissue preparation are essential for accurate measurement of endogenous cysteamine concentrations.

Acceptability of Accelerated-Processed Pork 1

Five market hogs were slaughtered to determine the microbial, organoleptic and appearance differences between accelerated and conventionally processed pork. The left side of each carcass was processed 4 h after slaughter, whereas the right side was fabricated at 24-h postmortem. Microbial sampling was conducted. Appearance and organoleptic characteristics were evaluated. Conventionally processed cuts of pork were rated higher for color and overall appearance than the accelerated-processed cuts until 120 h. Taste panel data revealed no significant difference in tenderness and juiciness between the accelerated and conventionally processed cuts. Differences in microbial load between the two processes after 120 h of storage were negligible; however, the accelerated processed cuts had a higher microbial load than the conventionally processed cuts except at 120 h. No measurable differences were found in the genera of microorganisms among samples from the accelerated and conventional methods. TBA values suggested little difference in rancidity between the two processes. Differences between the accelerated and the conventionally processed samples of pork were not enough to merit the preference of pork from one processing technique over the other method.

Effect of Thaw Conditions on Ground Beef 1

Three sampling periods were selected to acquire ground beef packages from two retail stores. Initially, samples were subjectively evaluated for color and overall appearance. Microbial load and taxonomy were determined and the samples were subsequently frozen. After frozen storage, one-half of the packages were thawed at 5 C for 4, 8, 24, 48 and 72 h, whereas the other samples were thawed at 25 C for the same periods. After thawing, samples were evaluated for the same characteristics as before freezing. Samples from each treatment were also evaluated for flavor, odor and overall acceptability. Appearance traits, taste and microbial load were affected (P < .05) by thaw time and temperature. Major groups of bacteria identified were: micrococci, Pseudomonas , streptococci, staphylococci, Flavobacterium , lactobacilli and coliforms. Salmonella and pathogenic Staphylococcus were not found. Those microorganisms which were identified were considered to be responsible for deterioration of appearance and taste attributes. Increased coliform growth at 25 C, especially after 8 h, suggests a need to thaw ground beef at refrigerated temperature to reduce public health concern. Results suggest that a proper thaw time and temperature to maintain acceptable appearance and taste of ground beef would be 24 h or less at refrigerated temperature.

Appearance and Microbial Quality of Thawed Retail Cuts of Beef, Pork and Lamb 1

Retail cuts of beef, pork and lamb were fabricated, packaged, evaluated for appearance traits, swabbed, and subsequently frozen. After storage for 7 days, one-half of the cuts were thawed at 4 C. The other cuts were thawed at 25 C. At 0, 4, 8, 24 and 48 h, the thawed retail cuts of meat were rated for appearance and swabbed. Taxonomy was conducted before freezing and after each thaw period. Evaluation revealed that differences (P < .05) in appearance for beef and pork existed between those samples thawed for 24 h and 0 h. Beef and pork cuts thawed at 25 C were less (P < .05) desirable in appearance after 24 h than for 8 h. Cuts thawed at 4 C for 48 h were less desirable than for 24 h. A higher thaw temperature increased (P < .05) microbial growth at 24 h on beef; but this trend was not observed among cuts of lamb and pork. Thaw time beyond 24 h increased (P < .05) the microbial load of only lamb and pork. Microorganisms most prevalent among samples were Pseudomonas , micrococci and staphylococci. These data suggest that retail cuts of meat should be thawed at refrigerated temperature, especially if thaw time exceeds 8 h.

Comparison of Bacterial Swab Samples Given Different Storage Treatments 1

Six paired sides of U.S. Good beef were swabbed to obtain microbial samples. Half of the beef sides were stored at an elevated temperature (25 C) for 8 h with subsequent storage for 12 h at 1 C before sampling, whereas the counterpart sides were stored the entire period at 1 C. Samples from adjacent areas were taken so that a comparison could be made of 0.03 M phosphate buffer and 0.1% peptone broth as diluents for swab samples. To evaluate the effect of storage time, swab samples were stored at 5 C for 1, 24, 48, 72, and 120 h before being transferred to Standard Plate Count Agar and subsequently incubated at 25 C. Results revealed that no differences (P>.05) existed between the effectiveness of a phosphate buffer solution and peptone broth as diluents for swab samples. Storage of swab samples at 1 C resulted in recovery of fewer microorganisms at 24, 48, and 72 h.