Ultrasound evaluation of portal venous gas and its mimics

Portal venous gas on abdominal ultrasound classically represents an indirect indicator of bowel ischemia, a critical condition which poses a high patient mortality and therefore warrants emergent corrective action. While the classic appearance of portal venous gas on ultrasound is well-described in the literature, the characteristic descriptors are nonspecific and may actually represent other less emergent mimics. Therefore, while radiologists should remain vigilant for the detection of findings corresponding to portal venous gas, they should also be aware of similar-appearing entities in order to provide the most accurate diagnosis. This pictorial essay will open with imaging examples of true portal venous gas attributable to bowel ischemia and describe the classic features which should alert radiologists to this specific diagnosis. Subsequently, this pictorial essay will provide imaging examples of other various other clinical entities which on ultrasound may share similar imaging characteristics. An important objective of this pictorial essay is to highlight distinguishing imaging features along with specific clinical circumstances for each pathological entity which can direct radiologists into identifying the correct diagnosis.

Direct stick embolization of a rectal venous malformation via transanal minimally invasive surgery

Rectal venous malformations (VMs) are rare clinical entities with variable patterns of presentation. Treatment requires unique, targeted strategies based on the symptoms, associated complications, and location, depth, and extent of the lesion. We present a rare case of a large, isolated rectal VM treated by direct stick embolization (DSE) using transanal minimally invasive surgery (TAMIS). A 49-year-old man had presented with a rectal mass incidentally detected on computed tomography urography. Magnetic resonance imaging and endoscopy revealed an isolated rectal VM. Elevated D-dimer levels concerning for localized intravascular coagulopathy warranted the use of prophylactic rivaroxaban. To avoid invasive surgery, DSE using TAMIS was performed successfully without complications. His postoperative recovery was uneventful, aside from a self-limiting and expected course of postembolization syndrome. To the best of our knowledge, this is the first reported case of TAMIS-assisted DSE of a colorectal VM. TAMIS shows promise for more widespread use in the minimally invasive, interventional management of colorectal vascular anomalies.

Creation of an Ex Vivo Renal Perfusion Model to Investigate Microwave Ablation

This study hypothesized that an ex vivo renal perfusion model can create smaller microwave ablation (MWA) measurements during perfused states compared with nonperfused states across multiple device settings. Nine bovine kidneys, a fluoroscopic compatible perfusion model, and a commercially-available clinical MWA system were used to perform 72 ablations (36 perfused and 36 nonperfused) at 9 different device settings. Comparing perfused and nonperfused ablations at each device setting, significant differences in volume existed for 6 of 9 settings (P < .05). Collapsed across time settings, the ablation volumes by power were the following (perfused and nonperfused, P value): 60 W, 2.3 cm³ ± 1.0 and 7.2 cm³ ± 2.7, P < .001; 100 W, 5.4 cm³ ± 2.1 and 11.5 cm³ ± 5.6, P < .01; and 140 W, 11.2 cm³ ± 3.7 and 18.7 cm³ ± 6.3, P < .01. Applied power correlated with ablation volume: perfused, 0.021 cm³/W and R = 0.462, P = .004, and nonperfused, 0.029 cm³/W and R = 0.565, P < .001. These results support that an ex vivo perfused organ system can evaluate MWA systems and demonstrate heat sink perfusion effects of decreased ablation size.

Creation of an ex-vivo bovine kidney flow model for testing embolic agents: work in progress

Objectives

To develop an ex- vivo perfusion flow model using a bovine kidney for future testing of embolic agents in an inexpensive and easy way.

Methods

Six bovine adult kidneys were used for this study. Kidneys were cannulated and perfused via a roller pump. Three embolic agents, coils, Gelfoam, and a glue mixture of Histoacryl + Lipiodol, were deployed by targeting three secondary segmental arteries per kidney via a 5Fr catheter under fluoroscopic guidance. Cannulation time, success rate of segmental artery selection and embolic agent deployment, total operational time, and fluoroscopy dose were recorded.

Results

Average kidney weight was 0.752 +/− 0.094 kg. All six bovine kidneys were successfully cannulated in 21.6 min +/− 3.0 min. Deployment of coils and glue was achieved in every case (12/12); however, Gelfoam injection was not successful in one instance (5/6, 83%). Coil deployment demonstrated no embolic effect while Gelfoam and glue injections demonstrated decreased distal contrast filling post-embolization. Mean dose area product was 12.9 ± 1.8 Gy·cm2, fluoroscopy time was 10 ± 4 min and operational time was 27 ± 8 min.

Conclusions

We describe the creation of an ex vivo bovine kidney flow model for the preclinical evaluation of different embolic materials. The flow model can be modified to provide extensive bench testing and it is a promising tool for hands -on training in basic and advanced embolization techniques .

18F-Fluciclovine Uptake in a Ureterocele

A 60-year-old man with prostate adenocarcinoma status post radical prostatectomy and bilateral pelvic lymph node dissection referred for restaging F-fluciclovine PET/CT due to rising serum prostate-specific antigen levels (1.1 ng/mL at that time of imaging). PET/CT images were obtained from the proximal thighs to the vertex of the skull approximately 3 to 5 minutes after the IV administration of 347.8 MBq (9.4 mCi) of F-fluciclovine. PET/CT imaging demonstrated a focus of abnormally increased F-fluciclovine uptake at the right ureterovesical junction. Subsequent MRI of the pelvis revealed that this focus corresponded to a benign ureterocele.

Correlation of Glottic Gap and Voice Impairment in Presbyphonia

OBJECTIVE/HYPOTHESIS

The objective of this study was to investigate the glottic gap area as a significant marker for the severity of presbyphonia as it relates to patient-reported outcome measures (Voice Handicap Index-10 [VHI-10]) and stroboscopic findings.

STUDY DESIGN

Retrospective case-control study conducted in an academic tertiary voice center.

METHODS

Patients seen at a tertiary voice clinic who were diagnosed with presbyphonia without other organic laryngeal pathology from January 2014 to December 2017 were included. Clinical data and laryngeal videostroboscopy videos were collected. Still images at the point of vocal process approximation during adduction were captured, and the glottic gap area was measured using ImageJ. These were compared to a control cohort. Correlations were made using Wilcoxon rank sum test, Mann-Whitney U test, and Pearson correlation coefficients.

RESULTS

Thirty-three patients were included. Inter-rater reliability of glottic area measurement was strong (intraclass correlation coefficient = 0.73, P < .001). Compared to controls, presbyphonia patients had a larger glottic gap area (P < .001) and greater open-phase quotient on laryngeal videostroboscopy (P < .001). Larger glottic gap area did not correlate with patient-reported vocal function as measured by VHI-10 (P = .79) and did not correlate with presence of secondary muscle tension dysphonia (P = .99). In the presbyphonia cohort, the glottic gap area did not correlate with age (P = .29).

CONCLUSIONS

Glottic gap area at the point of vocal process approximation during phonation can be reliably measured. Patients with presbyphonia have a larger glottic gap area and greater open-phase quotient on stroboscopy, but these do not correlate with patient-reported voice impairment or the presence of secondary muscle tension dysphonia (MTD). These data suggest that dysphonia severity in presbyphonia is not fully explained by a glottic gap or secondary MTD alone.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:1594-1598, 2021.

Uncommon presentations of an uncommon entity: OHVIRA syndrome with hematosalpinx and pyocolpos

Müllerian malformations result from defective fusion of the Müllerian ducts during development of the female reproductive system. The least common form of these malformations is Herlyn-Werner-Wunderlich syndrome characterized by obstructed hemivagina and ipsilateral renal anomaly (OHVIRA). The most common presentation of this syndrome is a mass secondary to hematocolpos, pain, and dysmenorrhea. Clinical diagnosis is very challenging and requires imaging studies in which ultrasound and MRI play an essential role in the diagnosis, classification and treatment plan. We report two cases of this syndrome, featuring two very rare clinical presentations: hematosalpinx and pyocolpos. The clinical course of the pathology is not standard and each patient is treated accordingly.

Intra-peritoneal leiomyoma of the round ligament in a patient with Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome

BACKGROUND

The occurrence of an extra-uterine leiomyoma, arising from the intra-peritoneal portion of the round ligament in a lady with Müllerian agenesis diagnosed at the age of forty is extremely rare. We report a case of this rare combination in a Middle Eastern woman.

CASE

A 40 years old lady, primarily amenorrheic, presented to our clinic for an infertility consultation. The work- up showed features suggestive of Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome with a leiomyoma arising from the intra-peritoneal part of the round ligament.

Carotid atherosclerotic calcification does not result in high signal intensity in MR imaging of intraplaque hemorrhage

BACKGROUND AND PURPOSE

Calcium can potentially shorten T1, generating high signal intensity in GREs. Because IPH appears as high signal intensity in MRIPH and the surface effects of calcium can potentially shorten T1 of surrounding water protons, the purpose of this study was to evaluate whether the high signal intensity seen on MRIPH could be attributed solely to IPH and not calcification.

MATERIALS AND METHODS

Eleven patients undergoing carotid endarterectomy were imaged by using MRIPH. Calcification was assessed by scanning respective endarterectomy specimens with a tabletop MicroCT. MRIPH/MicroCT correlation used an 8-segment template. Two readers evaluated images from both modalities. Agreement between MRIPH/MicroCT was measured by calculating Cohen κ.

RESULTS

High signal intensity was seen in 58.8% and 68.9% (readers 1 and 2, respectively) of MRIPH segments, whereas calcification was seen in 44.7% and 32.1% (readers 1 and 2, respectively) of MicroCT segments. High signal intensity seen by MRIPH showed very good but inverse agreement to calcification (κ = -0.90; P < .0001, 95% CI, -0.93 to -0.86, reader 1; and κ = -0.74; P < .0001; 95% CI, -0.81 to -0.69, reader 2). Most interesting, high signal intensity demonstrated excellent agreement with lack of calcification on MicroCT (κ = 0.92; P < .0001; 95% CI, 0.89-0.94, reader 1; and κ = 0.97; P < .0001; 95% CI, 0.96-0.99, reader 2). In a very small number of segments, high signal intensity was seen in MRIPH, and calcification was seen on MicroCT; however, these represented a very small proportion of segments with high signal intensity (5.9% and 1.6%, readers 1 and 2, respectively).

CONCLUSIONS

High signal intensity, therefore, reliably identified IPH, known to describe complicated plaque, rather than calcification, which is increasingly recognized as identifying more stable vascular disease.

Antioxidants increase lipopolysaccharide-stimulated TNF alpha release in murine macrophages: role for altered TNF alpha mRNA stability

Through their effects on gene activation, antioxidants have been reported to modulate cellular expression of several proinflammatory cytokines and adhesion molecules, an effect mediated by preventing translocation of the transcription factor nuclear factor-kappa B (NF-kappa B) into the nucleus. In addition, modulation of the intracellular redox state may have profound effects on cell activation and subsequent gene expression distinct from effects on NF-kappa B; these effects may account for the divergent effects of antioxidants on cytokine gene expression in various reports. In the present studies, we evaluated the effect of the antioxidant, pyrrolidine dithiocarbamate (PDTC), on murine and human myeloid cell tumor necrosis factor alpha (TNF alpha) gene and protein expression. PDTC-enhanced LPS-induced TNF alpha secretion in cells derived from a murine macrophage cell line (J774.1), as well as in primary murine peritoneal macrophages by 4-fold. The effect was both stimulus and species dependent, as TNF alpha secretion was attenuated by PDTC in human THP-1 cells and in murine cells stimulated with zymosan. Northern analysis demonstrated that these effects were evident at the level of mRNA expression. Electrophoretic mobility shift assays confirmed the down-regulatory effect of PDTC on human myeloid NF-kappa B activation, whereas in murine cells no such inhibitory effect was evident. Evaluation of TNF alpha mRNA stability in murine cells demonstrated that the potentiating effect of PDTC on TNF alpha mRNA expression was due to an increase in mRNA half-life from 37 to 93 min. Together, these data suggest that the effect of antioxidants on gene expression are both stimulus and species dependent and illustrate a novel mechanism whereby redox manipulation might modulate TNF alpha expression in vivo.

Beneficial effect of verapamil added to chronic ACE inhibitor treatment on renal function in hypertensive elderly patients

This study analysed the effect of low doses of verapamil added to chronic treatment with angiotensin-converting enzyme (ACE) inhibitors on blood pressure and serum creatinine levels in eight elderly hypertensive patients who had a steady increase of serum creatinine while on ACE inhibitors. The study was performed in eight elderly hypertensive subjects, five men and three women (mean age 70+/-2 years; systolic blood pressure 173+/-4 mm Hg; diastolic blood pressure 99+/-1 mm Hg) and serum creatinine of 1.60+/-0.27 mg/dl before treatment. During an average of 25 weeks, ACE inhibitors significantly reduced both systolic and diastolic blood pressures, but serum creatinine levels were increased over basal levels (0,68+/-0,20 mg/dl, p < 0.05). During an average of 10 weeks, the addition of verapamil did not decrease blood pressure further, but serum creatinine levels were reduced to baseline. Our study suggests that the addition of verapamil to ACE inhibitors can reverse ACE-induced increase in creatinine levels in elderly hypertensive patients in whom this side effect is observed.

The IL-1 beta-converting enzyme (caspase-1) inhibits apoptosis of inflammatory neutrophils through activation of IL-1 beta

IL-1 beta-converting enzyme (ICE), also known as caspase-1, subserves two dichotomous biologic roles. It processes newly synthesized pro-IL-1 beta to yield the active cytokine and, as the human homologue of the Caenorhabditis elegans gene product, ced-3, it also induces cellular apoptosis through the cleavage of key intracellular structural and regulatory proteins and through the catalytic activation of other caspase family members. We show here that two different proinflammatory stimuli, LPS and granulocyte-macrophage-CSF, up-regulate the expression of both ICE and IL-1 beta in human polymorphonuclear neutrophils, and that the ICE-dependent cleavage of pro-IL-1 beta results in delayed expression of the constitutive cell death program. The apoptotic delay can be blocked by inhibiting tyrosine kinases or NF-kappa B activation and by inhibiting protein synthesis. Since an antisense oligonucleotide for IL-1 beta, a blocking Ab to IL-1 beta, and preincubation with the IL-1R antagonist all prevent the delay in apoptosis, we conclude that IL-1 beta acts in an autocrine manner to inhibit granulocyte programmed cell death. We conclude that caspase-1 (ICE) subserves both pro- and antiapoptotic roles; the latter role is evident during inflammation as an inhibition of spontaneous neutrophil apoptosis through the processing of IL-1 beta. The ICE-dependent activation of IL-1 beta may represent a common autocrine pathway for the divergent stimuli that inhibit the constitutive expression of neutrophil programmed cell death during inflammation.

Thiol-mediated regulation of ICAM-1 expression in endotoxin-induced acute lung injury

The intracellular redox state regulates several aspects of cell function, suggesting that strategies directed toward altering the cellular redox state may modulate cell activation in inflammatory states. As the most abundant intracellular thiol, glutathione plays a critical role as an intracellular redox buffer. Using diethylmaleate (DEM) as a glutathione-depleting agent, we evaluated the effects of GSH depletion in a rodent model of polymorphonuclear neutrophil (PMN)-dependent acute lung injury. Rats received 500 microg of LPS by intratracheal challenge, inducing a 5.5-fold increase in lung permeability and sixfold increase in lung PMN content. Pretreatment with DEM prevented the LPS-induced increase in lung PMN influx and lung permeability. Northern analysis and immunohistochemical studies suggest that this effect may be mediated by preventing up-regulation of lung ICAM-1 mRNA and protein expression. This effect is specific to ICAM-1, because lung cytokine-induced neutrophil chemoattractant and TNF-alpha mRNA levels are unaffected. This finding is not unique to the lung, because a similar effect on PMN influx was recapitulated in a rodent model of chemical peritonitis. Further, in vitro studies demonstrated that pretreatment of HUVEC monolayers with DEM prevented both ICAM-1 up-regulation and PMN transendothelial migration. These data indicate the presence of a thiol-sensitive mechanism for modulating ICAM-1 gene expression and suggest a potential novel therapeutic strategy for diseases characterized by PMN-mediated tissue injury.

Pyrrolidine dithiocarbamate attenuates endotoxin-induced acute lung injury

Lung injury in the acute respiratory distress syndrome (ARDS) is in part due to polymorphonuclear leukocyte (PMN)-mediated oxidative tissue damage. By means of nuclear factor-kappaB (NF-kappaB) activation, oxidants may also induce several genes implicated in the inflammatory response. The dithiocarbamates are antioxidants with potent inhibitory effects on NF-kappaB. We postulated that the pyrrolidine derivative pyrrolidine dithiocarbamate (PDTC) would attenuate lung injury following intratracheal challenge with endotoxin (lipopolysaccharide; LPS) through its effect as an antioxidant and inhibitor of gene activation. Rats were given PDTC (1 mmole/kg) by intraperitoneal injection, followed by intratracheal administration of LPS. The transpulmonary flux of [125I] albumin (permeability index; PI) was used as a measure of lung injury. Northern blot analysis of total lung RNA was performed to assess induction of tumor necrosis factor-alpha (TNF-alpha) and intercellular adhesion molecule-1 (ICAM-1) messenger RNA (mRNA) as markers of NF-kappaB activation. The effect of in vivo treatment with PDTC on LPS-induced NF-kappaB DNA binding activity in macrophage nuclear extracts was evaluated with the electrophoretic mobility shift assay (EMSA). PDTC administration attenuated LPS-induced increases in lung permeability (PI = 0.16 +/- 0.02 for LPS versus 0.06 +/- 0.01 for LPS + PDTC; P < 0.05). TNF-alpha levels and PMN counts in bronchoalveolar lavage fluid (BALF) were unaffected, as were whole-lung TNF-alpha and ICAM-1 mRNA expression. PDTC had no effect on NF-kappaB activation as evaluated with EMSA. PDTC reduced lung lipid peroxidation as assessed by levels of malondialdehyde, without reducing neutrophil oxidant production. We conclude that PDTC attenuates LPS-induced acute lung injury. This effect occurs independently of any effect on NF-kappaB. PDTC reduces oxidant-mediated cellular injury, as demonstrated by a reduction in the accumulation of malondialdehyde. Administration of PDTC may represent a novel approach to limiting neutrophil-mediated oxidant injury.

Glutathione depletion prevents lipopolysaccharide-induced local skin inflammation

BACKGROUND

We have previously shown that the thiol-oxidizing agent diethyl maleate prevents lipopolysaccharide (LPS)-induced up-regulation of endothelial cell intercellular adhesion molecule-1 (ICAM-1) in vitro.

OBJECTIVE

To determine the effect of glutathione depletion on the development of local skin inflammation in vivo, a model known to be dependent on ICAM-1.

DESIGN

Swiss Webster mice were injected with intradermal LPS (30 micrograms) or isotonic saline solution.

INTERVENTION

Mice were pretreated for 1 hour with intraperitoneal diethyl maleate (6 mmol/kg) or corn oil vehicle.

MAIN OUTCOME MEASURES

Injection sites were harvested after 12 and 24 hours and evaluated for changes in vascular permeability and histological characteristics. To determine the mechanism underlying our findings, we evaluated skin ICAM-1 immunohistochemistry, levels of ICAM-1 protein and messenger RNA (mRNA), and neutrophil CD11b expression at the 24-hour point.

RESULTS

Diethyl maleate significantly decreased the skin permeability index in a dose-dependent fashion at 24 hours but not at 12 hours. Skin histological examination under light microscopy showed a marked LPS-induced neutrophil infiltration at 24 hours, which was inhibited with diethyl maleate pretreatment. Immunohistochemical examination showed that diethyl maleate reduced ICAM-1 expression. In keeping with the hypothesized mechanism, diethyl maleate attenuated the LPS-induced up-regulation of ICAM-1 mRNA by 44%. Diethyl maleate also slightly but insignificantly reduced CD11b expression in vivo.

CONCLUSIONS

Diethyl maleate markedly attenuates LPS-induced dermal inflammation, primarily through a reduction in ICAM-1 protein and mRNA expression. These data suggest that manipulation of the intracellular redox state may have a beneficial role in neutrophil-mediated inflammation.

Granulocytic differentiation of HL-60 cells results in spontaneous apoptosis mediated by increased caspase expression

HL-60 cells differentiating into neutrophil-like cells die an apoptotic death in vitro. Susceptibility to apoptosis is associated with decreased Bcl-2 protein and mRNA expression; however, the effect of differentiation on the expression of pro-apoptotic caspases is unknown. Spontaneous apoptosis occurred 6 days after retinoic acid treatment. Western blotting showed loss of Bcl-2 by day 7, and new expression of ICE (caspase 1) and CPP32 (caspase 3) protein by day 2. Northern analysis demonstrated loss of Bcl-2 mRNA and increases in ICE mRNA by day 2; CPP32 mRNA was unchanged. Differential Bcl-2 and ICE mRNA expression was also found when granulocytic differentiation was stimulated by DMSO. Differentiated HL-60 cell lysates exhibited functional ICE proteolytic activity. De novo caspase expression was responsible for the development of spontaneous apoptosis, since specific inhibitors of ICE (YVAD-CMK) and CPP32 (DEVD-CHO), inhibited retinoic acid induced spontaneous apoptosis. Functional maturation and susceptibility to apoptosis are both inducible and linked in this granulocyte precursor cell line.

Impaired apoptotic death signaling in inflammatory lung neutrophils is associated with decreased expression of interleukin-1 beta converting enzyme family proteases (caspases)

BACKGROUND

Fas and tumor necrosis factor receptor 1 (TNFR1) are membrane proteins that signal for apoptotic cell death by downstream activation of proteins of the interleukin-1 beta converting enzyme (ICE) family. Spontaneous apoptosis is delayed in neutrophils activated by transmigration into an inflammatory focus. In this study we evaluated the effects of transmigration on Fas and TNFR1-induced apoptosis and apoptotic gene expression.

METHODS

Sprague-Dawley rats were killed 4 hours after intratracheal challenge with 500 micrograms lipopolysaccharide (LPS). Neutrophils isolated from the systemic circulation (circulation) or bronchoalveolar lavage fluid (lung) were incubated with or without an agonistic antibody to Fas (clone CH-11, 100 ng/ml) or TNF (10 ng/ml) for 24 hours. Apoptosis and Fas expression were assessed by flow cytometry. Expression of the antiapoptotic protein Bcl-2 and proapoptotic proteins ICE and CPP32 were measured by Western blots.

RESULTS

Neutrophils transmigrating into the lung in response to LPS showed delayed apoptosis compared with circulating neutrophils and failed to undergo apoptosis in response to anti-Fas antibody or TNF-alpha. Fas expression was unaltered; however, TNFR1 expression was reduced. Bcl-2 was not detected in either group; both the pro- and active forms of ICE and active CPP32 were significantly decreased in lung neutrophils. The specific ICE inhibitor, YVAD-CMK, partially blocked the increased rates of apoptosis resulting from engagement of Fas or TNFR1.

CONCLUSIONS

Neutrophil transmigration retards apoptosis through engagement of the death receptors Fas and TNFR1. This refractory state is associated with reduced levels of proapoptotic proteins. Blunted responsiveness to physiologic apoptotic stimuli prolongs neutrophil functional survival during acute inflammation and may contribute to the tissue injury associated with acute respiratory distress syndrome.

VLA-4 integrin cross-linking on human monocytic THP-1 cells induces tissue factor expression by a mechanism involving mitogen-activated protein kinase

Adhesion molecules such as VLA-4 are important not only for monocyte adhesion to extracellular matrix proteins, but also for subsequent cell activation. Monocyte adherence to fibronectin or engagement of VLA-4 has been demonstrated to stimulate production of potent inflammatory mediators such as tumor necrosis factor-alpha, interleukin-1, and the procoagulant tissue factor protein. However, the intracellular signaling cascades leading to gene expression have not been elucidated. Using the human monocytic THP-1 cell line, VLA-4 cross-linking by monoclonal antibodies directed against its alpha4 and beta1 subunits produced a time-dependent increase in tyrosine phosphorylation of a broad range of cellular proteins. Using Western blot analysis directed against the phosphorylated form of the extracellular signal-related kinase (ERK) mitogen-activated protein (MAP) kinase proteins, as well as immunoprecipitation and in vitro kinase assays, we found that VLA-4 cross-linking increased ERK1/ERK2 tyrosine phosphorylation and activity. In conjunction, integrin cross-linking also increased NF-kappaB nuclear translocation and 4-h expression of tissue factor. Inhibition of tyrosine kinase activity with genistein (10 microg/ml) as well as selective MAP kinase inhibition with the MEK-1 inhibitor PD98059 abolished the VLA-4-dependent ERK tyrosine phosphorylation, inhibited NF kappaB nuclear binding, and abrogated tissue factor expression induced by both VLA-4 cross-linking and adhesion to fibronectin in THP-1 cells and human peripheral blood monocytes. These studies point to the involvement of the MAP kinase pathway in the activation of monocytic cells during transmigration to inflammatory sites.

gamma delta T-cell-human glial cell interactions. II. Relationship between heat shock protein expression and susceptibility to cytolysis

gamma delta T-cells have been implicated in the immunopathogenesis of multiple sclerosis (MS), possibly through interaction with heat shock proteins (hsp). We have previously demonstrated that human oligodendrocytes (OGC) express hsp on their surface and induce the proliferation and expansion of gamma delta T-cells. We also showed that gamma delta T-cells are highly cytolytic to OGC in vitro. The current study addresses whether gamma delta T-cell-induced cytotoxicity to OGC involves the recognition of hsp on OGC or some other ligand. We first compared the lytic potential for different human glial cells and found that gamma delta T-cells lysed OGC, microglia and human fetal astrocytes to the same extent, despite the preferential expression of hsp only on OGC. This suggested that either hsp was not involved in cytolytic recognition or that more than one ligand exists. To address this we used cell lines that either shared OGC properties of hsp expression and the ability to stimulate gamma delta T-cells (RPMI 8226, Daudi) or did not (U937) in cold target competition assays with OGC. Results demonstrated that although all the cell lines were effectively killed by gamma delta T-cells, only the RPMI 8226 and Daudi cells were able to effectively compete for lysis with the OGC. These results support the notion that probably more than one ligand for gamma delta T-cell cytotoxic recognition exists but hsp could still be involved in gamma delta T-cell-induced lysis of OGC. Regulating the expression of hsp on OGC might therefore be a way of interfering with potential gamma delta T-cell-induced damage in MS.

Retrovirus-mediated transfer of nuclear factor-kappa B subunit genes modulates I kappa B alpha and interferon beta expression

Nuclear factor (NF)-kappa B proteins regulate the transcription of numerous genes involved in the immune response, transcription control, and viral pathogenesis. To examine the effect of ectopic expression of NF-kappa B proteins on DNA-binding activity and gene expression, individual NF-kappa B subunit genes were introduced into NIH 3T3 cells via retrovirus-mediated gene transfer. Expression of NF-kappa B subunits RelA (p65), NF-kappa B1 (p105), NF-kappa B2 (p100), and c-Rel increased the basal level of nuclear NF-kappa B DNA binding in NIH 3T3 cells, whereas expression of delta RelA (p65 delta) and NF-kappa B2 (p52) subunits did not affect basal level activity. Tumor necrosis factor-alpha treatment of the NF-kappa B-expressing cells stimulated the induced level of DNA-binding activity, reflecting interaction between endogenous murine and transfected human NF-kappa B proteins. Interestingly, expression of RelA (p65), c-Rel, NF-kappa B1 (p105), NF-kappa B2 (p100), and NF-kappa B2 (p52) subunits increased I kappa B alpha protein levels from 3- to 30-fold, indicating that one mechanism to compensate for the increased expression of NF-kappa B proto-oncogenes was to increase the synthesis and/or stability of the regulatory I kappa B alpha protein. In addition, overexpression of RelA (p65), c-Rel, NF-kappa B2 (p100), and NF-kappa B2 (p52) altered the induction kinetics of IFN-beta mRNA after Sendai virus infection, whereas overexpression of NF-kappa B1 (p105) dramatically decreased IFN-beta mRNA induction.

Disruption of I kappa B alpha regulation by antisense RNA expression leads to malignant transformation

NF-kappa B transcription factors regulate the expression of a variety of genes involved in immune regulation and cell growth. In most cell types NF-kappa B proteins are localized in an inactive form in the cytoplasm coupled to the inhibitory I kappa B proteins. Viruses, cytokines, lipopolysaccharides and other stimulating agents promote the dissociation of the cytosolic NF-kappa B/I kappa B complexes, via phosphorylation and degradation of I kappa B, resulting in the translocation of DNA binding, NF-kappa B complexes to the nucleus. To further understand the association of I kappa B with cell growth regulation, the effect of ectopic expression of sense and antisense I kappa B genes was examined in NIH3T3 cells. Overexpression of I kappa B alpha antisense RNA but not I kappa B gamma antisense RNA decreased the steady state levels of I kappa B alpha protein, altered NF-kappa B DNA binding and gene activity and, most importantly, induced malignant transformation as measured by saturation density, growth in soft agar and tumorigenicity in nude mice. In contrast, overexpression of I kappa B alpha resulted in decreased saturation density, a flattened cellular morphology and decreased NF-kappa B dependent reporter gene activity. These results indicate that overexpression of an I kappa B alpha antisense RNA may disrupt the NF-kappa B/I kappa B autoregulatory loop, leading to cellular transformation. Our results raise the interesting possibility that I kappa B alpha represents a potential tumor suppressor activity.

Intestinal perforation in typhoid fever: a historical and state-of-the-art review

The appropriate therapy for intestinal perforation in typhoid fever has been controversial since the late 1880s. Around the turn of the century, surgery became the established mode of therapy, with a mortality of 69% based on 166 patients in the English-language medical literature, and continued to be the preferred treatment until the advent of chloramphenicol in 1948. At this time the surgical mortality was approximately 50%. Following the recovery of a few patients with perforation treated only with antimicrobial agents (six initially, then eventually 22), nonsurgical therapy became the accepted mode of treatment. This change was never justified and this review demonstrates this. Appropriate therapy is virtually always surgical, usually consisting of simple closure and irrigation. Chloramphenicol alone is inadequate antimicrobial therapy in a patient with perforation and must be supplemented by other antimicrobials directed against enteric aerobic gram-negative bacilli and enteric anaerobes.