Vertebral Venous Collaterals with Underlying Agenesis of the Inferior Vena Cava: Implications for Spinal Surgery

BACKGROUND

Congenital agenesis of the inferior vena cava (IVC) can lead to the development of a prominent venous collateral system within and around the spine due to the development of venous collaterals. In such patients, surgery can carry a risk of catastrophic bleeding or decompensation of a delicate venous drainage pattern during spinal manipulation or even epidural exploration.

CASE DESCRIPTION

A 49-year-old man with a congenital agenesis of the IVC presented with signs and symptoms of an L5 radiculopathy. A computed tomography scan of the lumbar spine showed the characteristic finding of fenestrated or "holey" pedicles within the lumbar spine, due to chronic venous engorgement within the pedicles.

CONCLUSIONS

To our knowledge, this is the first report to describe the characteristic sign of "holey" pedicles on radiographic imaging in a patient with an underdeveloped IVC. This finding may be useful for the detection of abnormal spinal venous anatomy. In such patients, spinal surgery may carry greater risks and requires special consideration.

Technical feasibility and safety of an intraoperative head-up display device during spine instrumentation

BACKGROUND

The primary aim of this study was to determine the safety and feasibility of capturing and streaming neuronavigation images onto a head-up display during spine instrumentation.

METHODS

Using a novel device, neuronavigation images were captured and transferred wirelessly via a password-encrypted network to the head-up display. At the end of the procedure, the surgeons completed a survey to gather their opinions of the system.

RESULTS

Forty pedicle screws were placed using the head-up display. The average screw placement time was slightly shorter when the head-up display was used (4.13 min with vs. 4.86 min without). The post-procedure survey demonstrated that 79% of surgeon's responses were positive.

CONCLUSION

A wearable head-up display can benefit current neuronavigation systems, but larger, outcomes-based trials are needed. Higher processing speed would allow streaming of higher resolution images. Along with an enlarged display, these may significantly improve utilization of this technology. Copyright © 2016 John Wiley & Sons, Ltd.

Management of severe traumatic flexion-distraction injuries in a multisystem trauma patient: A case report

STUDY DESIGN

Case report and relevant literature review.

OBJECTIVE

To discuss the management of severe flexion-distraction injury of the subaxial cervical spine in a multisystem trauma patient.

SUMMARY OF BACKGROUND DATA

Traumatic cervical spine injury from flexion-distraction injury can cause significant instability requiring extensive instrumentation complicated by vascular and soft tissue injuries.

METHODS

The medical record of a patient who suffered traumatic flexion-distraction injury was reviewed for relevant clinical and radiology data. A literature review on the management of traumatic cervical injuries was performed using the PubMed database.

RESULTS

We report a case of 21-year-old woman who suffered a C5-C6 flexion-distraction injury. After she underwent anterior cervical discectomy and fusion (ACDF), her care was transferred to the senior author (S.K.) due to the severity of the distraction. The patient returned to the OR the next day and underwent removal of implants at C5 and corpectomy with anterior and posterior instrumentation.

CONCLUSION

There are many ways to manage a flexion-distraction injury of the cervical spine. In a polytrauma patient, the surgical strategy can become complex. We present a surgical option with an acceptable outcome.

Takotsubo cardiomyopathy in the setting of acute hydrocephalus secondary to neurocysticercosis

We report the case of a 45-year-old male who presented with transient neurogenic stunned myocardium, or takotsubo cardiomyopathy, secondary to acute hydrocephalus caused by obstruction of the third ventricle by neurocysticercosis.

Redirecting pedicle screws: a revision spinal fusion strategy using three-dimensional image guidance

BACKGROUND

Pedicle screws are a preferred method for spinal fixation because of their three-column support and rigid posterior stabilization. The purpose of this study was to evaluate the outcome of patients requiring pedicle screw redirection, and to describe a technique using cone-beam computed tomography (cbCT).

METHODS

A retrospective review of 30 patients undergoing revision spinal fusion with redirection of pedicle screws was performed. Fifty pedicle screws were redirected in these patients using cbCT-based 3D image guidance. They were graded pre- and post-operatively using an established grading system.

RESULTS

No complications occurred in this study as a result of redirection. No pedicle breach was noted in all of the redirected pedicle screws.

CONCLUSION

Redirection of misplaced pedicle screws using cbCT-based 3D image guidance seems to be safe and accurate in our experience. Further studies are needed to establish its safety, accuracy, fusion rate, and clinical outcome compared with other methods. Copyright © 2016 John Wiley & Sons, Ltd.

A Reappraisal of Anterior Communicating Artery Aneurysms

BACKGROUND:

Wide-necked anterior communicating artery aneurysms represent a subset of lesions with challenging endovascular treatment despite new endoluminal and intrasaccular devices.

OBJECTIVE:

To assess the long-term clinical and angiographic outcomes of stent-assisted embolization for wide-necked anterior communicating artery aneurysms.

METHODS:

Between March 2008 and March 2014, 32 patients with unruptured wide-necked AComm aneurysms were treated using stent-assisted embolization. The Glasgow Outcome Scale was reviewed at the time of discharge and at latest follow-up. Ischemic and hemorrhagic events were also recorded and analyzed. Aneurysm occlusion was evaluated post-intervention and on subsequent follow-up evaluations.

RESULTS:

Successful stent deployment was achieved in all cases, but in 1 patient the coils could not be contained inside the aneurysm, and the procedure was aborted without complications. The distal segment of the stent was positioned in the ipsilateral A2 in 16 patients, in the contralateral A2 in 15 patients, and in the contralateral A1 in 1 patient. There were no periprocedural thromboembolic or hemorrhagic complications. The rate of major complications was 6%. One patient developed intracranial hemorrhage related to antiplatelet therapy and another had ischemic events due to in-stent stenosis. Angiographic follow-up was available for 26 aneurysms and during a mean follow-up of 22 months, 81% of the lesions were completely occluded and 8% had a small residual neck. The retreatment rate for residual aneurysms was 3%.

CONCLUSION:

Our long-term results suggest that stent-assisted embolization for anterior communicating artery aneurysms may be considered an excellent treatment option with an adequate combination of safety profile and effectiveness.

Feasibility and Safety of Pipeline Embolization Device in Patients With Ruptured Carotid Blister Aneurysms

BACKGROUND:

Treatment of internal carotid ruptured blister aneurysms (IC-RBA) presents many challenges to neurosurgeons because of the high propensity for rebleeding during intervention. The role of a Pipeline Embolization Device (PED) in the treatment of this challenging aneurysm subtype remains undefined despite theoretical advantages.

OBJECTIVE:

To present a series of 11 patients treated with a PED and to discuss the management and results of this novel application of flow diverters.

METHODS:

Medical records of patients who presented with IC-RBA from May 2011 to March 2013 were retrospectively reviewed at 6 institutions in the United States. All relevant data were independently compiled.

RESULTS:

A total of 12 IC-RBAs in 11 patients were treated during the study period. Nine (75%) were treated with a single PED; 1 was treated with 2 PEDs; 1 was treated with coils and 1 PED; and 1 was treated with coils and 2 PEDs. Three (27%) had major perioperative complications: middle cerebral artery territory infarction, vision loss, and death. Seven patients demonstrated complete obliteration of the aneurysm in postoperative imaging. Early clinical outcomes were favorable (modified Rankin Scale score, 0–2) in all 10 survivors.

CONCLUSION:

This study demonstrates the feasibility and safety of using the PED to treat IC-RBA with fair initial results. The proper introduction and management of antiplatelet regimen are key for successful results. Bleeding complications related to dual antiplatelet therapy were similar to those in previous studies of stent-assisted coiling for the same population. Larger cohort analysis is needed to define the precise role of flow diverters in the treatment of IC-RBA.

Identification of stringent response-related and potential serological proteins released from Bacillus anthracis overexpressing the RelA/SpoT homolog, Rsh Bant

RelA and SpoT synthesize ppGpp, a key effector molecule that facilitates the adaptation of bacteria to nutrient starvation and other stresses, known as the stringent response. To investigate the role of Rsh Bant , a putative RelA/SpoT homolog (encoded by BAS4302) in Bacillus anthracis, we examined the alteration of the secretome profiles after the overexpression of a functional His-Rsh Bant protein in the B. anthracis strain Sterne at the stationary growth phase. In the ppGpp-deficient E. coli mutant strain CF1693, overexpression of Rsh Bant restored a ppGpp-dependent growth defect on minimal glucose media. The secretome profiles obtained using a two-dimensional electrophoresis (2-DE) analysis were altered by overexpression of Rsh Bant in B. anthracis. Among the 66 protein spots differentially expressed >1.5-fold, the 29 proteins were abundant for further identification using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Functional categorization of those proteins implicated their involvement in various biological activities. Taken together, our results imply that overexpression of a functional His-Rsh Bant can lead to the increased levels of intracellular ppGpp in B. anthracis, resulting in the significant changes in its secretome profiling. The stringent response-controlled proteins identified are likely useful as potential targets for serodiagnostic applications.

Guided-mode resonant coherent light absorbers

We present a new class of coherent perfect absorbers based on guided-mode resonance in thin semiconductor films. Using particle-swarm optimization methods, we design a thin-film amorphous silicon grating that maximizes coherent modulation of the absorbance. The optimized device exhibits a maximum scattering power of ∼94% and a power absorption limit approaching 100% at the 1550-nm wavelength.

Comparison between sitagliptin as add-on therapy to insulin and insulin dose-increase therapy in uncontrolled Korean type 2 diabetes: CSI study

AIM

Individuals requiring insulin therapy for type 2 diabetes often require escalation of their regimen to achieve glycaemic control. Optimal management strategies for uncontrolled type 2 diabetes would improve glycaemic control without hypoglycaemia and weight gain. This study compared the efficacy and tolerability of adding sitagliptin, an oral dipeptidyl peptidase-4 inhibitor, and an up to 20% increase in insulin dose in patients with uncontrolled type 2 diabetes on insulin therapy.

METHODS

We conducted a 24-week, randomized, active-competitor, parallel-group study in subjects with uncontrolled type 2 diabetes [haemoglobin A1c (HbA1c) = 7.5-11%] currently using insulin therapy. Subjects were randomly assigned to either the sitagliptin adding (100 mg daily, n = 70) or an insulin-increasing arm (≥ 10% at week 12 and ≥ 10% at week 24, n = 70) while continuing other medications.

RESULTS

Average baseline HbA1c was 9.2% in both groups. HbA1c decreased more at 24 weeks in the sitagliptin adding than the insulin-increasing arm (-0.6 ± 0.1% vs. -0.2 ± 0.1%, p < 0.01). Insulin was increased by 25% at 24 weeks in the insulin-increasing group. Hypoglycaemic events were less common and less severe in sitagliptin adding arm than insulin-increasing arm (7.0 vs. 14.3 events per patient-year, p < 0.05). Weight was stable in the sitagliptin adding subjects (68.6 ± 11.6 vs. 68.1 ± 11.4 kg) but increased in the insulin-increasing subjects (66.2 ± 10.6 vs. 67.4 ± 9.7 kg, p < 0.05). Other adverse events occurred at similar rates in both arms.

CONCLUSIONS

Compared to a 25% increase in insulin dose, adding sitagliptin to an insulin-based regimen was more effective at lowering HbA1c and associated with less hypoglycaemia and weight gain over 24 weeks.

CLINICAL TRIAL NUMBER

NCT01100125.

Repression of flagella motility in enterohemorrhagic Escherichia coli O157:H7 by mucin components

Whole genome-scale transcriptome analysis of enterohemorrhagic Escherichia coli (EHEC) O157:H7 EDL933 was performed to investigate the influence of mucin components on the EHEC gene expression. Here we report that the 732 candidate genes were differentially expressed by the presence of 0.5% porcine stomach mucin, including the 8 flagella-related genes. Quantitative real-time PCR analyses revealed that the transcription expression of the flg genes (encoding the structural components for flagella basal body) was down-regulated by the mucin components. Indeed, bacterial swarming motility was drastically reduced when grown on 0.3% trypton agar plates containing the mucin. These results imply that gastrointestinal (GI) mucin is a possible environmental signal which negatively regulates the flagellation of EHEC O157:H7 in the GI tract.

Prevalence of genes for enterotoxins, toxic shock syndrome toxin 1 and exfoliative toxin among clinical isolates of Staphylococcus pseudintermedius from canine origin

A total of 74 Staphylococcus pseudintermedius strains were isolated from the 99 clinical cases of canine pyoderma or chronic otitis in our veterinary teaching hospital during May 2006-February 2008. In this study, we examined the genetic distribution of staphylococcal pyogenic toxins such as staphylococcal enterotoxins A (sea), B (seb), C (sec), D (sed), E (see), and toxic shock syndrome toxin 1 (tst) as well as the previously characterized S. intermedius exfoliative toxin (siet) among those isolates. The polymerase chain reaction analyses with the toxin gene-specific primers revealed that 18 (24.3%) of 74 S. pseudintermedius isolates carried the sec genes, but none of the sea, seb, sed, see and tst genes. Further DNA sequencing analysis of the amplified sec genes revealed that they all belonged to the canine type C staphylococcal enterotoxin (SEC(canine) ) whose superantigenic activity has been demonstrated. In addition to the sec(canine) genes, our polymerase chain reaction results showed that all the 74 isolates carried the siet gene. Since both SEC(canine) and SIET toxins are known to be biologically active, it would be interesting to investigate how those toxins are involved in the pathogenesis of the canine diseases by S. pseudintermedius such as pyoderma or chronic otitis.

High prevalence of Fluoroquinolone- and Methicillin-resistant Staphylococcus pseudintermedius isolates from canine pyoderma and otitis externa in veterinary teaching hospital

Recently, a total of 74 Staphylococcus pseudintermedius isolates were collected from clinical cases of canine pyoderma and otitis externa in Korea. In this study, we examined in vitro fluoroquinolone resistance among those isolates using a standard disk diffusion technique. The results demonstrated that approximately 18.9% to 27.0% of the isolates possessed bacterial resistance to both veterinary- and human-licensed fluoroquinolones except one isolate, including moxifloxacin (18.9% resistance), levofloxacin (20.3% resistance), ofloxacin (24.3% resistance), ciprofloxacin (25.7% resistance), and enrofloxacin (27.0% resistance). Most surprisingly, 14 out of 74 (18.9%) isolates were resistant to all the five fluoroquinolones evaluated. Moreover, a PCR detection of the methicillin resistance gene (mecA) among the 74 isolates revealed that 13 out of 25 (52.0%) mecA-positive isolates, but only 7 out of 49 (14.3%) mecA-negative isolates, were resistant to one or more fluoroquinones. Taken together, our results imply that bacterial resistance to both veterinary- and human-use fluoroquinolones becomes prevalent among the S. pseudintermedius isolates from canine pyoderma and otitis externa in Korea as well as that the high prevalence of the mecA-positive S. pseudintermedius isolates carrying multiple fluoroquinolone resistance could be a potential public health problem.

A brief overview of Escherichia coli O157:H7 and its plasmid O157

Enterohemorrhagic Escherichia coli O157:H7 is a major food-borne pathogen causing severe disease in humans worldwide. Healthy cattle are a reservoir of E. coli O157:H7 and bovine food products and fresh produce contaminated with bovine waste are the most common sources for disease outbreaks in the United States. E. coli O157:H7 also survives well in the environment. The ability to cause human disease, colonize the bovine gastrointestinal tract, and survive in the environment, requires that E. coli O157:H7 adapt to a wide variety of conditions. Three major virulence factors of E. coli O157:H7 have been identified including Shiga toxins, a pathogenicity island called the locus of enterocyte effacement, and an F-like plasmid, pO157. Among these virulence factors, the role of the pO157 is least understood. This review provides a board overview of E. coli O157:H7 with an emphasis on the pO157.

All blood, no stool: enterohemorrhagic Escherichia coli O157:H7 infection

Enterohemorrhagic Escherichia coli serotype O157:H7 is a pathotype of diarrheagenic E. coli that produces one or more Shiga toxins, forms a characteristic histopathology described as attaching and effacing lesions, and possesses the large virulence plasmid pO157. The bacterium is recognized worldwide, especially in developed countries, as an emerging food-borne bacterial pathogen, which causes disease in humans and in some animals. Healthy cattle are the principal and natural reservoir of E. coli O157:H7, and most disease outbreaks are, therefore, due to consumption of fecally contaminated bovine foods or dairy products. In this review, we provide a general overview of E. coli O157:H7 infection, especially focusing on the bacterial characteristics rather than on the host responses during infection.

Enhanced inhibitory effect of ultra-fine granules of red ginseng on LPS-induced cytokine expression in the monocyte-derived macrophage THP-1 cells

Red ginseng is one of the most popular traditional medicines in Korea because its soluble hot-water extract is known to be very effective on enhancing immunity as well as inhibiting inflammation. Recently, we developed a new technique, called the HAC-gearshift system, which can pulverize red ginseng into the ultra-fine granules ranging from 0.2 to 7.0 μm in size. In this study, the soluble hot-water extract of those ultra-fine granules of red ginseng (URG) was investigated and compared to that of the normal-sized granules of red ginseng (RG). The high pressure liquid chromatographic analyses of the soluble hot-water extracts of both URG and RG revealed that URG had about 2-fold higher amounts of the ginsenosides, the biologically active components in red ginseng, than RG did. Using quantitative RT-PCR, cytokine profiling against the Escherichia coli lipopolysaccharide (LPS) in the monocyte-derived macrophage THP-1 cells demonstrated that the URG-treated cells showed a significant reduction in cytokine expression than the RG-treated ones. Transcription expression of the LPS-induced cytokines such as TNF-α, IL-1β, IL-6, IL-8, IL-10, and TGF-β was significantly inhibited by URG compared to RG. These results suggest that some biologically active and soluble components in red ginseng can be more effectively extracted from URG than RG by standard hot-water extraction.

Spontaneous leukocyte activation and oxygen-free radical generation in end-stage renal disease

Oxidative stress and inflammation are common features and major mediators of atherosclerosis in end-stage renal disease (ESRD). Available evidence for oxidative stress in ESRD is indirect and based on accumulation of byproducts of interactions of reactive oxygen species (ROS) with various molecules. Inflammation is a major cause of oxidative stress. To explore the direct link between oxidative stress and inflammation in ESRD, we studied leukocyte integrin expression and ROS production in 18 ESRD patients and 18 controls. ESRD patients showed elevated plasma malondialdehyde (MDA) and increased superoxide and hydrogen peroxide (H(2)O(2)) production by granulocytes and monocytes before dialysis. Hemodialysis resulted in a further rise in plasma MDA and H(2)O(2) production by granulocytes and monocytes. Surface expression of Mac-1 (CD11b and CD18) on granulocytes and monocytes was significantly increased (denoting cell activation) in ESRD patients. Granularity of granulocytes was significantly reduced before dialysis and declined further after dialysis. The magnitude of ROS production by granulocytes and monocytes was directly related with CD11b expression as well as plasma ferritin and parathyroid hormone levels and was inversely related to protein catabolic rate. Thus, this study provides direct evidence of spontaneous leukocyte activation and increased ROS generation (hence the link between oxidative stress and inflammation) in ESRD patients.

Naphthalenemethyl ester derivative of dihydroxyhydrocinnamic acid, a component of cinnamon, increases glucose disposal by enhancing translocation of glucose transporter 4

AIMS/HYPOTHESIS

Cinnamon extracts have anti-diabetic effects. Phenolic acids, including hydrocinnamic acids, were identified as major components of cinnamon extracts. Against this background we sought to develop a new anti-diabetic compound using derivatives of hydroxycinnamic acids purified from cinnamon.

METHODS

We purified hydroxycinnamic acids from cinnamon, synthesised a series of derivatives, and screened them for glucose transport activity in vitro. We then selected the compound with the highest glucose transport activity in epididymal adipocytes isolated from male Sprague-Dawley rats in vitro, tested it for glucose-lowering activity in vivo, and studied the mechanisms involved.

RESULTS

A naphthalenemethyl ester of 3,4-dihydroxyhydrocinnamic acid (DHH105) showed the highest glucose transport activity in vitro. Treatment of streptozotocin-induced diabetic C57BL/6 mice and spontaneously diabetic ob/ob mice with DHH105 decreased blood glucose levels to near normoglycaemia. Further studies revealed that DHH105 increased the maximum speed of glucose transport and the translocation of glucose transporter 4 (GLUT4, now known as solute carrier family 2 [facilitated glucose transporter], member 4 [SLC2A4]) in adipocytes, resulting in increased glucose uptake. In addition, DHH105 enhanced phosphorylation of the insulin receptor-beta subunit and insulin receptor substrate-1 in adipocytes, both in vitro and in vivo. This resulted in the activation of phosphatidylinositol 3-kinase and Akt/protein kinase B, contributing to the translocation of GLUT4 to the plasma membrane.

CONCLUSIONS/INTERPRETATION

We conclude that DHH105 lowers blood glucose levels through the enhancement of glucose transport, mediated by an increase in insulin-receptor signalling. DHH105 may be a valuable candidate for a new anti-diabetic drug.

Cryopreservation of potato cultivated varieties and wild species: critical factors in droplet vitrification

The applicability of cryopreservation protocols to a broad range of genotypes is a key issue for genebanks. We tried to identify the critical factors causing differences in survival of cryopreserved shoot tips using potato varieties coming from cultivated and wild species. The droplet-vitrification method, a combination of droplet-freezing and solution-based vitrification, was selected from several protocols. High survival after freezing was observed after dehydration with PVS2 for 20 min, cooling shoot tips placed in a droplet of PVS2 solution on aluminum foil strips by immersing the foil strips in liquid nitrogen, warming them by plunging the foil strips into a 0.8 M sucrose solution (at 40 degrees C) for 30 s and unloading in 0.8 M sucrose for 30 min. This optimized protocol was successfully applied to 12 accessions with survival ranging between 64.0 and 94.4%.

Involvement of the Escherichia coli O157:H7(pO157) ecf operon and lipid A myristoyl transferase activity in bacterial survival in the bovine gastrointestinal tract and bacterial persistence in farm water troughs

Escherichia coli O157:H7 is an important food-borne pathogen that causes hemorrhagic colitis and the hemolytic-uremic syndrome in humans. Recently, we reported that the pO157 ecf (E. coli attaching and effacing gene-positive conserved fragments) operon is thermoregulated by an intrinsically curved DNA and contains the genes for bacterial surface-associated proteins, including a second copy of lipid A myristoyl transferase, whose chromosomal copy is the lpxM gene product. E. coli O157:H7 survives and persists well in diverse environments from the human and bovine gastrointestinal tracts (GIT) to nutrient-dilute farm water troughs. Transcriptional regulation of the ecf operon by intrinsic DNA curvature and the genetic redundancy of lpxM that is associated with lipid A modification led us to hypothesize that the pO157 ecf operon and lpxM are associated with bacterial survival and persistence in various in vivo and ex vivo environments by optimizing bacterial membrane structure and/or integrity. To test this hypothesis, three isogenic ecf operon and/or lpxM deletion mutants of E. coli O157:H7 ATCC 43894 were constructed and analyzed in vitro and in vivo. The results showed that a double mutant carrying deletions in the ecf and lpxM genes had an altered lipid A structure and membrane fatty acid composition, did not survive passage through the bovine GIT, did not persist well in farm water troughs, had increased susceptibility to a broad spectrum of antibiotics and detergents, and had impaired motility. Electron microscopic analyses showed gross changes in bacterial membrane structure.

Thermoregulation of the Escherichia coli O157:H7 pO157 ecf operon and lipid A myristoyl transferase activity involves intrinsically curved DNA

Escherichia coli O157:H7 survives in diverse environments from the ruminant gastrointestinal tract to cool nutrient-dilute water. We hypothesized that the gene regulation required for this flexibility includes intrinsically curved DNA that responds to environmental changes. Three intrinsically curved DNAs were cloned from the E. coli O157:H7 virulence plasmid (pO157), sequenced and designated Bent 1 through Bent 3 (BNT1, BNT2 and BNT3). Compared to BNT1 and BNT3, BNT2 had characteristics typical of intrinsically curved DNA including electrophoretic gel retardation at 4 degrees C, six partially phased adenine:thymine tracts and transcriptional activation. BNT2::lacZ operon fusions showed that BNT2 activated transcription at 24 degrees C compared to 37 degrees C and was partially repressed by a bacterial nucleoid-associated protein H-NS. BNT2 regulated the E. coli attaching and effacing gene-positive conserved fragments 1-4 (ecf1-4) that are conserved in Shiga toxin-producing E. coli associated with human disease. Experimental analyses showed that ecf1-4 formed an operon. ecf1, 2 and 3 encoded putative proteins associated with bacterial surface polysaccharide biosynthesis and invasion and ecf4 complemented a chromosomal deletion of lpxM encoding lipid A myristoyl transferase. Mass spectrometric analysis of lipid A from ecf and lpxM single and double mutants showed that myristoylation was altered at lower temperature.

Acid resistance of Escherichia coli O157:H7 from the gastrointestinal tract of cattle fed hay or grain

There has been strong debate as to whether feeding cattle hay prior to slaughter will reduce the number and/or virulence of Escherichia coli O157:H7 in the bovine gastrointestinal tract (GIT). This study addressed this issue by comparing numbers, persistence, and acid resistance of generic coliforms and E. coli O157:H7 from various gastrointestinal tract sites of cattle fed grain or hay. Mature Angus steers, doubly cannulated into the rumen and duodenum were inoculated with E. coli O157:H7. Aliquots of digesta from the rumen, duodenum, and rectum were cultured directly or acid shocked (pH 2.0) and then cultured to determine acid resistance. The culture technique used was as sensitive as standard immunomagnetic bead separation protocols. E. coli O157:H7 from hay-fed or grain-fed cattle were similarly acid resistant in all GIT locations. In contrast, generic coliforms from the rumen and rectum of hay-fed animals were more sensitive to an acid shock than coliforms from those GIT locations in grain-fed animals. E. coli O157:H7 colonized the most distal region of the GIT and was not consistently cultured from the rumen or the duodenum. Numbers in the upper GIT did not predict numbers or persistence of E. coli O157:H7 in rectal samples. Grain-feeding or hay-feeding did not affect survival of E. coli O157:H7 in the rumen, nor its passage through the abomasum (pH 2.0) to the duodenum. These data show that generic coliforms behave differently in the bovine host than E. coli O157:H7 and that E. coli O157:H7 acid resistance was independent of animal diet.

Role of glutamic acid decarboxylase in the pathogenesis of type 1 diabetes

Glutamic acid decarboxylase (GAD) is considered to be one of the strongest candidate autoantigens involved in triggering beta-cell-specific autoimmunity. The majority of recent onset type 1 diabetes patients and pre-diabetic subjects have anti-GAD antibodies in their sera, as do nonobese diabetic (NOD) mice, one of the best animal models for human type I diabetes. Immunization of young NOD mice with GAD results in the prevention or delay of the disease as a result of tolerizing autoreactive T cells. Autoimmune diabetes can also be prevented by the suppression of GAD expression in antisense GAD transgenic mice backcrossed with NOD mice for seven generations. These results support the hypothesis that GAD plays an important role in the development of T-cell-mediated autoimmune diabetes. However, there is some controversy regarding the role of GAD in the pathogenesis of diabetes. Whether GAD truly plays a key role in the initiation of this disease remains to be determined. The examination of the development of insulitis and diabetes in beta-cell-specific GAD knockout NOD mice will answer this remaining question.