Hydraulic conductivity assessment of falling head percolation tests used for the design of on-site wastewater treatment systems

The suitability of a location for an on-site wastewater treatment process (for areas which lack access to centralised wastewater treatment systems) requires an assessment of the permeability of the soil into which the effluent will be discharged. In many jurisdictions this is determined using some type of in-situ percolation test. Falling head percolation tests, which give a value of percolation time (PT) that is empirically related to the notion of hydraulic conductivity, are widely used as they are relatively simple to carry out, but the test does not have a sound theoretical framework and test methods are not standardised internationally. In comparison, the saturated hydraulic conductivity of a soil obtained from a constant head well permeameter test is independent of test conditions, and so is a more suitable metric for design. A database of over 900 falling head tests carried out across a range of different subsoil types in Ireland has been collated, all with the inherent limitations of the existing regulative framework regarding the percolation test and soil texture assessment. These tests were then modelled using Hydrus 2-D numerical modelling simulations to determine equivalent field saturated hydraulic conductivity (Kfs) values and thereby provide a correlation with PT values across the range of subsoil conditions. In addition, falling head tests have been carried out in parallel to constant head permeameter tests in the field and compared against the relationship derived from the broad dataset of simulated results. This revealed an optimal solution by which to determine Kfs from the field permeameter test (using parameters recommended for most structured soils from clays to loams). The trendline based on Irish data was also compared against more generic formulations of the relationship between PT, and Kfs and shown to match closely, particularly the Reynolds (2016) 'unified' methodology. Finally, the Irish threshold PT limits for on-site wastewater treatment have been converted to Kfs values and compared against other international standards.

COVID-19 Pandemic: The Circus is Over, for the Moment

This critical essay responds to the COVID-19 pandemic and subsequent lockdown in Victoria from the perspective of a retired Aboriginal academic and reflects on personal responsibility, Indigenous history, and resilience.

An evaluation of semidistributed-pipe-network and distributed-finite-difference models to simulate karst systems

Several different approaches have been developed to model the specific characteristics of karst aquifers, taking account of their inherent complex spatial and temporal heterogeneities. This paper sets out the development of a semidistributed modelling approach for applications in an Irish karst context using urban drainage software. The models have proven to be very useful for different studies, with examples given for the ecohydrology of ephemeral karst lakes, extreme groundwater-flood alleviation, karst network investigation, submarine groundwater discharge, and quantification of different recharge and flow components. The limitations of the approach are also highlighted, in particular not being able to simulate diffuse infiltration and flow paths explicitly across the groundwater catchment. Hence, a more distributed, finite-difference modelling approach using MODFLOW Unstructured Grid (USG) with the newly developed Connected Linear Network (CLN) process is then compared against the semidistributed approach on the same karst catchment. Whilst it has proven difficult to achieve the same levels of model performance in simulating the spring flows in the distributed model compared to the semidistributed model, the ability to interrogate the flow paths at any point on the three-dimensional aquifer is demonstrated, which can give new insights into flows (and potential contaminant transport) through such complex systems. The influence of the proximity of highly transmissive conduits on the flow dynamics through the much-lower transmissive matrix cells in which the network is embedded has been particularly investigated.

Pain expectancy, prevalence, severity, and patterns following donor nephrectomy: Findings from the KDOC Study

Postoperative pain is an outcome of importance to potential living kidney donors (LKDs). We prospectively characterized the prevalence, severity, and patterns of acute or chronic postoperative pain in 193 LKDs at six transplant programs. Three pain measurements were obtained from donors on postoperative Day (POD) 1, 3, 7, 14, 21, 28, 35, 41, 49, and 56. The median pain rating total was highest on POD1 and declined from each assessment to the next until reaching a median pain-free score of 0 on POD49. In generalized linear mixed-model analysis, the mean pain score decreased at each pain assessment compared to the POD3 assessment. Pre-donation history of mood disorder (adjusted ratio of means [95% confidence interval (CI)]: 1.40 [0.99, 1.98]), reporting "severe" on any POD1 pain descriptors (adjusted ratio of means [95% CI]: 1.47 [1.12, 1.93]) and open nephrectomy (adjusted ratio of means [95% CI]: 2.61 [1.03, 6.62]) were associated with higher pain scores across time. Of the 179 LKDs who completed the final pain assessment, 74 (41%) met criteria for chronic postsurgical pain (CPSP), that is, any donation-related pain on POD56. Study findings have potential implications for LKD education, surgical consent, postdonation care, and outcome measurements.

Immunophenotyping extracellular vesicles using the CellStream flow cytometer

Extracellular vesicles are membrane derived structures that include exosomes, microvesicles and apoptotic bodies. The importance of extracellular vesicles as key mediators of intercellular communication is not well understood. Exosomes have been shown to transfer molecules between cells, potentially transmitting signals. Exosomes are released under normal physiological conditions; however, they are also believed to serve as mediators in the pathogenesis of neurological, vascular, haematological and autoimmune diseases as well as cancer. Quantifying and characterizing extracellular vesicles in a reproducible and reliable manner is challenging due to their small size (exosomes range from 30 to 100 nm in diameter). Extracellular vesicle analysis can be done using high-magnification microscopy; however, this technique has a very low throughput. Attempts to analyze extracellular vesicles using traditional PMT based flow cytometers has been hampered by the limit of detection of such small particles and their low refractive index. To overcome these limitations, we have employed the Amnis CellStream that has the advantage of high throughput flow cytometry with higher sensitivity to small particles due to the CCD based, time-delay-integration image capturing system. Data will be presented using the CellStream flow cytometer to immunophenotype extracellular vesicles derived from red blood cells and platelets.

Can Early Changes in Vital signs Predict Duration of Antibiotic Therapy in Suspected Neonatal Sepsis?

Aims Suspected sepsis remains a leading causes of Neonatal Intensive Care Unit admission, with infants often receiving 48-72 hours of empirical antibiotic therapy. Early in treatment it is difficult to predict infants who will require prolonged antibiotic therapy. Our aim was to assess if vital sign measurements in the initial period of treatment can predict those neonates requiring prolonged antibiotic therapy in term and late-preterm infants. Methods Data was retrospectively collected over 1 year on neonates admitted to our institute for antibiotics. Infants were classified as standard (<48hours duration) or prolonged (>48hours duration) antibiotic therapy. Results Respiratory rate on admission and 12 hours after initiation of therapy correlated significantly with duration of antibiotic therapy and infants requiring prolonged therapy were more likely to have one or more abnormal vital signs 12 hours after initiation of treatment (p<0.05). Conclusion Respiratory rate shows a weak positive correlation with antibiotic duration. Infants requiring prolonged therapy were more likely to have abnormal vital signs 12 hours after initiating antibiotic therapy. Changes in vital signs maybe useful in detecting infants who will require prolonged antibiotic therapy.

Mood, body image, fear of kidney failure, life satisfaction, and decisional stability following living kidney donation: Findings from the KDOC study

Prior studies demonstrate that most living kidney donors (LKDs) report no adverse psychosocial outcomes; however, changes in psychosocial functioning at the individual donor level have not been routinely captured. We studied psychosocial outcomes predonation and at 1, 6, 12, and 24 months postdonation in 193 LKDs and 20 healthy controls (HCs). There was minimal to no mood disturbance, body image concerns, fear of kidney failure, or life dissatisfaction, indicating no incremental changes in these outcomes over time and no significant differences between LKDs and HCs. The incidence of any new-onset adverse outcomes postdonation was as follows: mood disturbance (16%), fear of kidney failure (21%), body image concerns (13%), and life dissatisfaction (10%). Multivariable analyses demonstrated that LKDs with more mood disturbance symptoms, higher anxiety about future kidney health, low body image, and low life satisfaction prior to surgery were at highest risk of these same outcomes postdonation. It is important to note that some LKDs showed improvement in psychosocial functioning from pre- to postdonation. Findings support the balanced presentation of psychosocial risks to potential donors as well as the development of a donor registry to capture psychosocial outcomes beyond the mandatory 2-year follow-up period in the United States.

Illuminating T cell – APC interactions using multispectral imaging flow cytometry

Interaction between antigen-specific T cells and antigen presenting cells (APC) cognate ligand involve reorganization of the cytoskeleton and recruitment of adhesive and signaling molecules to the site of intercellular contact. Sustained adhesion of T cells to APCs and formation of the immunological synapse after T cell receptor stimulation are required for the antigen-specific response. One way to measure an immunological synapse is by fluorescently labeling the molecules that have been recruited to the synapse and imaging by fluorescence microscopy. However, immunological synapses are rare and therefore difficult to analyze objectively and statistically by traditional microscopy methods. To overcome these problems, we employed the Amnis brand ImageStream to objectively collect imagery of large numbers of cells. In this study, Raji B cells loaded with Staphylococcal enterotoxin B (SEB) were incubated with human T cells to create T cell-APC conjugates. Cells were stained in various combinations for CD3, CD19, Actin, LFA-1, Lck and NFkB. Using multispectral imaging flow cytometry we demonstrate image-based parameters that were used to assess the frequency of conjugates with an organized immunological synapse, evaluate the specific location of the adhesion and signaling molecules LFA-1 and Lck within the immunological synapse complex and measure the nuclear localization of NFkB in the T cell-APC conjugates.

A novel method to classify subpopulations in murine spleen and blood using multiparametric imaging flow cytometry

Being able to identify the lymphocytes, monocytes, and neutrophils (granuolcytes) subpopulations in murine spleen and peripheral blood is an important step of the analysis of the immune system. Conventionally, this task is accomplished by performing immunofluorescence staining of specific cell surface markers. However, given the distinct morphology of each of these subpopulations as well as the cell imageries obtained using the Image Stream technology, we attempt to identify 3cell types in the spleen and peripheral blood samples of C57BL/6 and BALB/c mice based solely on the Bright Field (BF), Side Scatter (SSC) and nuclear images without using any specific markers for the cell types. We will then compare the results obtained using this novel method with that obtained using immunofluorescence. We hope that the results will serve to both validate our methodology and highlight the value offered by this objective, automated, and quantitative approach towards other murine immune cell analysis, particularly in those situations where immunofluorescence based subpopulation detections are either unfeasible(due to fluorochrome conflicts) or impractical (due to high sample sizes).

Measurement of IL-6 levels in live cells using RNA detection probe with Imaging Flow Cytometer

Acute inflammatory responses to infection and tissue damage are orchestrated by release of cytokines, primarily from macrophages and mast cells, but also by endothelium and tumor cells. A key initiator of the inflammatory response is tumor necrosis factor alpha (TNF-alpha), which binds to its receptor on target cells and activates a pro-inflammatory transcriptional program via the transcription factor NFkB. A critical downstream target of NFkB is the gene encoding interleukin-6, which stimulates an array of anti-infection processes, including synthesis of acute-phase proteins by the liver, proliferation of B cells, neutrophil production in bone marrow, and differentiation of Th17 helper T cells. Although beneficial in the context of attacking infection, dysregulation of IL-6 plays a deleterious role in autoimmune disease and cancer. In this study, we introduce a new method for measuring NFkB translocation by looking at the increase in IL-6 mRNA levels in the THP-1 suspension cell line using SmartFlare™ RNA detection probes. The ability to detect RNA in live cells and to acquire multi-spectral images of large numbers of cells allows for the accurate assessment of IL-6 mRNA levels in THP-1 cells.

Direct and Indirect Costs Following Living Kidney Donation: Findings From the KDOC Study

Some living kidney donors (LKDs) incur costs associated with donation, although these costs are not well characterized in the United States. We collected cost data in the 12 mo following donation from 182 LKDs participating in the multicenter prospective Kidney Donor Outcomes Cohort (KDOC) Study. Most LKDs (n = 167, 92%) had one direct cost or more following donation, including ground transportation (86%), health care (41%), meals (53%), medications (36%), lodging (23%), and air transportation (12%). LKDs missed 33 072 total work hours, 40% of which were unpaid and led to $302 175 in lost wages (mean $1660). Caregivers lost $68 655 in wages (mean $377). Although some donors received financial assistance, 89% had a net financial loss in the 12-mo period, with one-third (33%) reporting a loss exceeding $2500. Financial burden was higher for those with greater travel distance to the transplant center (Spearman's ρ = 0.26, p < 0.001), lower household income (Spearman's ρ = -0.25, p < 0.001), and more unpaid work hours missed (Spearman's ρ = 0.52, p < 0.001). Achieving financial neutrality for LKDs must be an immediate priority for the transplant community, governmental agencies, insurance companies, nonprofit organizations, and society at large.

Predonation Direct and Indirect Costs Incurred by Adults Who Donated a Kidney: Findings From the KDOC Study

Limited information exists on the predonation costs incurred by eventual living kidney donors (LKDs). Expenses related to completion of the donation evaluation were collected from 194 LKDs participating in the multi-center, prospective Kidney Donor Outcomes Cohort (KDOC) Study. Most LKDs (n = 187, 96%) reported one or more direct costs, including ground transportation (80%), healthcare (24%), lodging (17%) and air transportation (14%), totaling $101 484 (USD; mean = $523 ± 942). Excluding paid vacation or sick leave, donor and companion lost wages totaled $35 918 (mean = $187 ± 556) and $14 378 (mean = $76 ± 311), respectively. One-third of LKDs used paid vacation or sick leave to avoid incurring lost wages. Few LKDs reported receiving financial support from the transplant candidate (6%), transplant candidate's family (3%), a nonprofit organization (3%), the National Living Donor Assistance Center (7%), or transplant center (3%). Higher total costs were significantly associated with longer distance traveled to the transplant center (p < 0.001); however, total costs were not associated with age, sex, race/ethnicity, household income, marital status, insurance status, or transplant center. Moderate predonation direct and indirect costs are common for adults who complete the donation evaluation. Potential LKDs should be advised of these possible costs, and the transplant community should examine additional strategies to reimburse donors for them.

10 Gb/s InP-based Mach-Zehnder modulator for operation at 2 μm wavelengths

We report on the first InP-based Mach-Zehnder modulator (MZM) employing quantum-confined Stark effect (QCSE) for operation around 2000 nm. The polarization sensitive device is based on 15 compressively strained quantum wells and achieves an electro-optic (EO) bandwidth of at least 9 GHz, with a DC extinction ratio of ~9 dB, and a V(π)L ~9.6 V.mm. We demonstrate back-to-back communication with a 10 Gb/s pseudo-random bit sequence (PRBS) of length 2(7)-1 at a wavelength around 2000 nm.

Abstract 3074: Detection and enumeration of circulating tumor cells using imaging flow cytometery

Circulating tumor cells (CTCs), released into the bloodstream from primary and metastatic cancers, are valuable tools for understanding tumor biology. However, since they are rare, their detection is hampered by low efficiency and a lack of standardization in current technologies. To overcome these problems, we used Imaging Flow Cytometery along with fluorescent RNA detection probes to collect imagery from large number of cells to assess the number of CTCs. In this study, we spiked peripheral blood mononucleated cells (PBMCs) with SKBR-3 human breast cancer cells and added probes for relevant RNA targets such as EPCAM and Her-2. Taking advantage of the probes’ ability to detect RNA in live cells, combined with the capacity to acquire multi-spectral images of large numbers of cells, we demonstrate image based parameters that can be used to assess the frequency of CTCs in an objective and statistically significant manner.

Citation Format: Shobana Vaidyanathan, Don Weldon, David Basiji, Philip Morrissey. Detection and enumeration of circulating tumor cells using imaging flow cytometery. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3074. doi:10.1158/1538-7445.AM2014-3074

Cellular image analysis and imaging by flow cytometry

Imaging flow cytometry combines the statistical power and fluorescence sensitivity of standard flow cytometry with the spatial resolution and quantitative morphology of digital microscopy. The technique is a good fit for clinical applications by providing a convenient means for imaging and analyzing cells directly in bodily fluids. Examples are provided of the discrimination of cancerous from normal mammary epithelial cells and the high-throughput quantitation of fluorescence in situ hybridization (FISH) probes in human peripheral blood mononuclear cells. The FISH application will be enhanced further by the integration of extended depth-of-field imaging technology with the current optical system.

Donor-transmitted parvovirus infection in a kidney transplant recipient presenting as pancytopenia and allograft dysfunction

Parvovirus B19 is a nonenveloped single-stranded DNA virus that commonly causes a benign childhood infection typically manifesting as a "slapped-cheek" rash. In immunodeficient hosts, this infection can cause persistent anemia and occasionally pancytopenia. Recently, direct renal involvement has been reported in renal transplant recipients leading to various forms of glomerulopathy and allograft dysfunction. Most cases are primary infections and are donor transmitted through the transplanted organ. Clinical and virological response to intravenous immunoglobulin (Ig) is usually excellent. We describe a case of donor-transmitted parvovirus infection in a 23-year-old male who received his first cadaver renal transplant. The patient had an uncomplicated postoperative course with immediate graft function. Eight weeks after transplantation, he presented with fever, polyarthralgia, pancytopenia, and allograft dysfunction. Serological studies revealed elevated IgM titers against parvovirus B19. A renal biopsy was performed, which showed no evidence of acute rejection but with moderate degree of tubular damage. Parvovirus B19 viral DNA was detected in the renal tissue via polymerase chain reaction (PCR). The patient received a 10-day course of intravenous Ig (400 mg/kg/day) with excellent response. His blood count normalized and the allograft improved to baseline function. The incidence of parvovirus infection in renal transplant patients is probably underestimated, because patients are not routinely screened for it and anemia and/or pancytopenia in these patients are often ascribed to immunosuppressive drugs. Because this infection is treatable, we conclude that parvovirus B19 infection should be actively considered in transplant patients presenting with pancytopenia and allograft dysfunction.

HealthSense: how changes in sensory physiology, sensory psychology and sociocognitive factors influence food choice

HealthSense is a multi-centre shared cost research project in sensory and consumer sciences. This project was initiated in response to changing population demographics, which predict a significant increase in the older age group. The primary objective of HealthSense is to determine accurately the effects of ageing on the perceptual abilities of the sensory systems, and ultimately how age-related change determines sensory preferences and food choice. The project is carried out by 24 participating institutes located in 10 different European countries. The project is funded by the European Commission Quality of Life Fifth Framework Programme (QLKI-CT-1999-00010).

Determination of drug exposure using hair: application to child protective cases

The use of hair as a specimen for the determination of drug use remains controversial. Scientists disagree upon whether environmental drug contamination (e.g. smoke) can be differentiated from actual drug use. Children whose parents use drugs (particularly crack) at home are considered to be at risk. Using the hair of the children to determine exposure gives extra credibility to the child protective services and allows them to remove children from dangerous households. Children are tested when there are credible reasons for suspecting drug exposure. In Blackhawk Country, Iowa, this program was implemented in late 1994, and since then many children have tested positively for drugs, the majority of the hair containing cocaine or methamphetamine. In some cases, cocaethylene and benzoylecgonine were also found in the hair of the children. While the presence of benzoylecgonine can be explained by exposure to crack smoke, the presence of cocaethylene suggests ingestion of cocaine and alcohol. Blackhawk Country Juvenile Court have found the program to be so useful in helping children, that they have extended hair testing from Child Protective allegation investigations to ongoing court cases and even delinquency hearings.

Cephalosporins to carbapenems: 1-oxygenated carbapenems and carbapenams

The photo "Wolff" rearrangement of readily available 2-diazoceph-3-em oxides (1) directly affords carbapen-2-ems, allowing a facile entry into a ring system previously accessible only by total synthesis, lengthly semisynthesis or fermentation. The chirality of the cephalosporin is accurately translated into the corresponding carbapenem. The resulting 1-oxocarbapenems (2) were selectively transformed through reduction into 1-oxygenated carbapenems and carbapenams (3 and 4, respectively). On microbiological screening, a carbapenem (3c) was found to possess a broad spectrum of activity. An interesting antibacterial profile was discovered for a carbapenam (26).

Molecular cloning and characterization of protective outer membrane protein P.69 from Bordetella pertussis

Protein P.69 is localized on the outer membrane of Bordetella pertussis and is one of the virulence factors believed to contribute to the disease state of whooping cough. We demonstrate that protein synthesis of P.69 is under genetic control of the vir locus. Using oligonucleotide probes derived from the protein sequence of a cyanogen bromide fragment, we have cloned the gene for P.69 from B. pertussis CN2992. Analysis of the DNA sequence reveals a G + C-rich gene capable of encoding a protein of 910 amino acids with a Mr of 93,478, suggesting that P.69 is a processed form of a larger precursor. In common with some of the genes in the pertussis toxin operon, the sequence CCTGG was found 5' to the ATG initiation codon. At the 3' end, 29 bases after the TAA stop codon, the sequence GTTTTTCCT was found and may have some function in transcription termination. A full-length clone of the gene for P.69 carried by the cosmid pBPI69 was unable to direct the expression of P.69 protein in an Escherichia coli host. The generation of P.69-fusion products allowed the detection of P.69-specific protein products synthesized in E. coli.

The influence of IL-1 treatment on the reconstitution of the hemopoietic and immune systems after sublethal radiation

The influence of IL-1 administration on the recovery of the hemopoietic and immune systems from sublethal irradiation was assessed. Mice were irradiated (750 R) and injected twice daily with purified recombinant derived IL-1 beta (200 ng/injection). At various times after irradiation, the functional capacity of the hemopoietic and immune systems was determined. It was found that IL-1 therapy resulted in a significantly greater number of granulocyte-macrophage-CSF responsive colony-forming cells in the bone marrow of the irradiated mice on days 5 and 11 postirradiation but not at later times. In addition the radiation induced neutropenia recovered quicker in the IL-1-treated mice with significantly greater numbers of peripheral blood granulocytes being seen on days 15 and 20 after irradiation. The influence of IL-1 therapy on the recovery of the immune system was also assessed. Of note was the observation that mice receiving IL-1 therapy had chronically hypoplastic thymi. Although thymic cellularity increased with time after irradiation in the control mice, there was no such increase in the IL-1-treated mice. Similarly, the number of pre-B cells in the marrow of these mice was also diminished. Thus, in the IL-1-treated mice the regeneration of the peripheral immune function was retarded, characterized by a general lymphopenia and decreased splenic responses to mitogenic stimuli.

The influence of IL-1 treatment on the reconstitution of the hemopoietic and immune systems after sublethal radiation

The influence of IL-1 administration on the recovery of the hemopoietic and immune systems from sublethal irradiation was assessed. Mice were irradiated (750 R) and injected twice daily with purified recombinant derived IL-1 beta (200 ng/injection). At various times after irradiation, the functional capacity of the hemopoietic and immune systems was determined. It was found that IL-1 therapy resulted in a significantly greater number of granulocyte-macrophage-CSF responsive colony-forming cells in the bone marrow of the irradiated mice on days 5 and 11 postirradiation but not at later times. In addition the radiation induced neutropenia recovered quicker in the IL-1-treated mice with significantly greater numbers of peripheral blood granulocytes being seen on days 15 and 20 after irradiation. The influence of IL-1 therapy on the recovery of the immune system was also assessed. Of note was the observation that mice receiving IL-1 therapy had chronically hypoplastic thymi. Although thymic cellularity increased with time after irradiation in the control mice, there was no such increase in the IL-1-treated mice. Similarly, the number of pre-B cells in the marrow of these mice was also diminished. Thus, in the IL-1-treated mice the regeneration of the peripheral immune function was retarded, characterized by a general lymphopenia and decreased splenic responses to mitogenic stimuli.

Cloning and nucleotide sequence of the aroA gene of Bordetella pertussis

The aroA locus of Bordetella pertussis, encoding 5-enolpyruvylshikimate 3-phosphate synthase, has been cloned into Escherichia coli by using a cosmid vector. The gene is expressed in E. coli and complemented an E. coli aroA mutant. The nucleotide sequence of the B. pertussis aroA gene was determined and contains an open reading frame encoding 442 amino acids, with a calculated molecular weight for 5-enolpyruvylshikimate 3-phosphate synthase of 46,688. The amino acid sequence derived from the nucleotide sequence shows homology with the published amino acid sequences of aroA gene products of other microorganisms.

Retropharyngeal hematomas

Hyperextension of the cervical spine in the elderly can cause retropharyngeal hematomas. We report this unusual cause of retropharyngeal hematoma in a 77-year-old women. The airway must be thoroughly evaluated in any such patient in whom this lesion is suspected.

Cloning and expression of two Streptococcus mutans glucosyltransferases in Escherichia coli K-12

Chromosomal DNA from Streptococcus mutans strain MFe28 (serotype h) was cloned in the bacteriophage vector lambda L47.1. Two classes of recombinants were found which expressed glucosyltransferase activity in phage plaques: (i) gtfS, which expressed a glucosyltransferase synthesizing a water-soluble, dextranase-sensitive glucan, and (ii) gtfI, which expressed a primer-dependent glucosyltransferase synthesizing an insoluble glucan.

Molecular analysis of the virulence determinants of enterotoxigenic Escherichia coli isolated from domestic animals: applications for vaccine development

Enterotoxigenic strains of Escherichia coli are an important cause of diarrhoeal disease in young farm animals. Several virulence determinants have been shown to play a major role in the pathogenicity of these strains. The molecular structure of some of these determinants including adhesion fimbriae, heat-labile toxins and heat-stable toxins have been elucidated. This knowledge has made possible the development of novel vaccines effective against enterotoxigenic strains. In this short review, the structure of these virulence factors will be described and the implications for the development of future vaccines will be discussed.

Intrinsic laryngeal muscle activity in a spastic dysphonia patient

EMG activity from four intrinsic laryngeal muscles (thyroarytenoid, posterior cricoarytenoid, interarytenoid, and cricothyroid) was obtained from one female spastic dysphonia patient while she performed a variety of speech and nonspeech tasks. These tasks were performed before and during a period of temporary unilateral laryngeal muscle paralysis. In the nonparalyzed condition, adductory muscle activity showed intermittent sudden increases that coincided with momentary voice arrests. These muscle patterns and accompanying voice interruptions were not present either when speech was produced in falsetto register or at anytime during the paralysis condition. The data suggest that individuals with this type of spastic dysphonia have normal morphology of recurrent laryngeal nerves and intrinsic laryngeal muscles, which means that the triggering mechanism(s) for spastic dysphonia symptoms must be located at some point neurologically upstream from the larynx.

Physiologic stages of vocal reaction time

A simple vocal reaction time (RT) task was performed by 10 male subjects while measures from intrinsic laryngeal muscles and subglottal air pressure were obtained simultaneously. Based only on each subject's fastest time among 15 trials, RT values were similar to the latencies previously observed in normal subjects. The mean of the subjects' fastest trials was 185 ms (range: 160-250 ms). Shortest latency values obtained for each measure were interarytenoid muscle, 50 ms; thyroarytenoid muscle, 60 ms; posterior cricoarytenoid muscle, 80 ms; subglottal air pressure rise, 125 ms. From these data estimates were made of 115 ms for the shortest respiratory system latency and 25 ms for the minimal central processing time. These data suggest that fastest vocal RTs are determined principally by the temporal constraints involved in activating pulmonary rather than laryngeal structures.

Selenium-independent glutathione peroxidase activity in rabbit liver

The reduction of linoleic acid hydroperoxide catalyzed by rat liver cytosol was previously shown to be catalyzed by a selenium-dependent glutathione peroxidase. In contrast, the activity in rabbit liver cytosol could also be attributed to a selenium-dependent peroxidase. The selenium-independent peroxidase copurified with glutathione transferase B and was completely inhibited by antitransferase B antiserum and transferase substrates. These results suggest that glutathione transferase B in rabbit liver cytosol is involved in the intracellular decomposition of lipid peroxide and could explain the lower selenium requirement of rabbits in comparison with other species.